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Sample records for acquired erlotinib resistance

  1. Niclosamide overcomes acquired resistance to erlotinib through suppression of STAT3 in non-small cell lung cancer

    PubMed Central

    Li, Rui; Hu, Zhongliang; Sun, Shi-Yong; Chen, Zhuo G.; Owonikoko, Taofeek K.; Sica, Gabriel L.; Ramalingam, Suresh S.; Curran, Walter J.; Khuri, Fadlo R.; Deng, Xingming

    2013-01-01

    The emergence of resistance to epidermal growth factor receptor (EGFR) inhibitor therapy is a major clinical problem for patients with non-small cell lung cancer (NSCLC). The mechanisms underlying tumor resistance to inhibitors of the kinase activity of EGFR are not fully understood. Here we found that inhibition of EGFR by erlotinib induces STAT3 phosphorylation at Tyr705 in association with increased Bcl2/Bcl-XL at both mRNA and protein levels in various human lung cancer cells. PTPMeg2 is a physiologic STAT3 phosphatase that can directly dephosphorylate STAT3 at the Tyr705 site. Intriguingly, treatment of cells with erlotinib results in downregulation of PTPMeg2 without activation of STAT3 kinases (i.e. JAK2 or c-Src), suggesting that erlotinib enhanced phosphorylation of STAT3 may occur, at least in part, from suppression of PTPMeg2 expression. Since elevated levels of phosphorylated STAT3 (pSTAT3), Bcl2 and Bcl-XL were observed in erlotinib-resistant lung cancer (HCC827/ER) cells as compared to erlotinib-sensitive parental HCC827 cells, we postulate that erlotinib-activated STAT3/Bcl2/Bcl-XL survival pathway may contribute to acquired resistance to erlotinib. Both blockage of Tyr705 phosphorylation of STAT3 by niclosamide and depletion of STAT3 by RNA interference in HCC827/ER cells reverses erlotinib resistance. Niclosamide in combination with erlotinib potently represses erlotinib-resistant lung cancer xenografts in association with increased apoptosis in tumor tissues, suggesting that niclosamide can restore sensitivity to erlotinib. These findings uncover a novel mechanism of erlotinib resistance and provide a novel approach to overcome resistance by blocking the STAT3/Bcl2/Bcl-XL survival signaling pathway in human lung cancer. PMID:23894143

  2. Axl mediates acquired resistance of head and neck cancer cells to the epidermal growth factor receptor inhibitor erlotinib.

    PubMed

    Giles, Keith M; Kalinowski, Felicity C; Candy, Patrick A; Epis, Michael R; Zhang, Priscilla M; Redfern, Andrew D; Stuart, Lisa M; Goodall, Gregory J; Leedman, Peter J

    2013-11-01

    Elevated expression and activity of the epidermal growth factor receptor (EGFR) is associated with development and progression of head and neck cancer (HNC) and a poor prognosis. Clinical trials with EGFR tyrosine kinase inhibitors (e.g., erlotinib) have been disappointing in HNC. To investigate the mechanisms mediating resistance to these agents, we developed an HNC cell line (HN5-ER) with acquired erlotinib resistance. In contrast to parental HN5 HNC cells, HN5-ER cells exhibited an epithelial-mesenchymal (EMT) phenotype with increased migratory potential, reduced E-cadherin and epithelial-associated microRNAs (miRNA), and elevated vimentin expression. Phosphorylated receptor tyrosine kinase profiling identified Axl activation in HN5-ER cells. Growth and migration of HN5-ER cells were blocked with a specific Axl inhibitor, R428, and R428 resensitized HN5-ER cells to erlotinib. Microarray analysis of HN5-ER cells confirmed the EMT phenotype associated with acquired erlotinib resistance, and identified activation of gene expression associated with cell migration and inflammation pathways. Moreover, increased expression and secretion of interleukin (IL)-6 and IL-8 in HN5-ER cells suggested a role for inflammatory cytokine signaling in EMT and erlotinib resistance. Expression of the tumor suppressor miR-34a was reduced in HN5-ER cells and increasing its expression abrogated Axl expression and reversed erlotinib resistance. Finally, analysis of 302 HNC patients revealed that high tumor Axl mRNA expression was associated with poorer survival (HR = 1.66, P = 0.007). In summary, our results identify Axl as a key mediator of acquired erlotinib resistance in HNC and suggest that therapeutic inhibition of Axl by small molecule drugs or specific miRNAs might overcome anti-EGFR therapy resistance. PMID:24026012

  3. The insulin-like growth factor 1 receptor causes acquired resistance to erlotinib in lung cancer cells with the wild-type epidermal growth factor receptor.

    PubMed

    Suda, Kenichi; Mizuuchi, Hiroshi; Sato, Katsuaki; Takemoto, Toshiki; Iwasaki, Takuya; Mitsudomi, Tetsuya

    2014-08-15

    Epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor (TKI) therapy often provides a dramatic response in lung cancer patients with EGFR mutations. In addition, moderate clinical efficacy of the EGFR-TKI, erlotinib, has been shown in lung cancer patients with the wild-type EGFR. Numerous molecular mechanisms that cause acquired resistance to EGFR-TKIs have been identified in lung cancers with the EGFR mutations; however, few have been reported in lung cancers with the wild-type EGFR. We used H358 lung adenocarcinoma cells lacking EGFR mutations that showed modest sensitivity to erlotinib. The H358 cells acquired resistance to erlotinib via chronic exposure to the drug. The H358 erlotinib-resistant (ER) cells do not have a secondary EGFR mutation, neither MET gene amplification nor PTEN downregulation; these have been identified in lung cancers with the EGFR mutations. From comprehensive screening of receptor tyrosine kinase phosphorylation, we observed increased phosphorylation of insulin-like growth factor 1 receptor (IGF1R) in H358ER cells compared with parental H358 cells. H358ER cells responded to combined therapy with erlotinib and NVP-AEW541, an IGF1R-TKI. Our results indicate that IGF1R activation is a molecular mechanism that confers acquired resistance to erlotinib in lung cancers with the wild-type EGFR.

  4. Chemotherapy With Erlotinib or Chemotherapy Alone in Advanced Non-Small Cell Lung Cancer With Acquired Resistance to EGFR Tyrosine Kinase Inhibitors

    PubMed Central

    Oxnard, Geoffrey R.; Digumarthy, Subba; Muzikansky, Alona; Jackman, David M.; Lennes, Inga T.; Sequist, Lecia V.

    2013-01-01

    Purpose. Epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer has an oncogene-addicted biology that confers sensitivity to EGFR tyrosine kinase inhibitors (TKIs). Published data suggest that EGFR addiction persists after development of TKI acquired resistance, leading many clinicians to continue TKI with subsequent chemotherapy; however, this strategy has not been formally evaluated. Methods. We retrospectively reviewed an institutional database to identify patients with advanced EGFR mutation with acquired resistance who subsequently received chemotherapy. Patients were classified as receiving chemotherapy with continued erlotinib or chemotherapy alone. We assessed differences in outcomes between the two strategies. Results. Seventy-eight patients were included, 34 treated with chemotherapy and erlotinib and 44 treated with chemotherapy alone. Objective response rate was evaluable in 57 patients and was 41% for those treated with chemotherapy and erlotinib and 18% for those treated with chemotherapy alone. After adjusting for chemotherapy regimen and length of initial TKI course, the odds ratio for the response rate was 0.20 (95% confidence interval: 0.05–0.78; p = .02) favoring treatment with chemotherapy and erlotinib. The median progression-free survival was 4.4 months on chemotherapy and erlotinib and 4.2 months on chemotherapy alone (adjusted hazard ratio = 0.79; 95% confidence interval: 0.48–1.29; p = .34). There was no difference in overall survival. Conclusion. This is the first study, to our knowledge, to demonstrate that continuation of EGFR TKI with chemotherapy in patients with acquired resistance improves outcomes compared with chemotherapy alone. We observed an improved response rate but no difference in progression-free survival or overall survival. A larger prospective clinical trial is needed to evaluate this promising strategy further. PMID:24072220

  5. Valproic acid, an inhibitor of class I histone deacetylases, reverses acquired Erlotinib-resistance of lung adenocarcinoma cells: a Connectivity Mapping analysis and an experimental study.

    PubMed

    Zhuo, Wenlei; Zhang, Liang; Zhu, Yi; Xie, Qichao; Zhu, Bo; Chen, Zhengtang

    2015-01-01

    Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKI) have been used as a powerful targeting therapeutic agent for treatment of lung adenocarcinoma for years. Nevertheless, the efficacy of TKI was hampered by the appearance of acquired TKI-resistance. In the present study, we aimed to search, predict, and screen the agents that can overcome the acquired TKI-resistance of lung adenocarcinoma by using the expression profiles of differentially expressed genes (DEGs) and Connectivity map (CMAP). The profiles of DEGs were obtained by searching GEO microarray database, and then, they were submitted to CMAP for analysis in order to predict and screen the agent that might reverse the TKI-resistance of lung cancer cells. Next, the effects of the selected agent on TKI-resistant cancer cells were tested and the possible signaling pathways were also evaluated. As a result, valproic acid (VPA) was selected. Then, we used a low-concentration of VPA that has little effect on the cell growth for analysis. Interestingly, the results showed that treatment with a combination of VPA and Erlotinib significantly led to a decrease in cell viability and an increase in cell apoptosis for TKI-resistant HCC827-ER cells, relative to those treated with VPA or Erlotinib alone. Further experiments confirmed that inhibition of MAPK and AKT might be involved in this process. Analyzing the DEGs through the CMAP is a good strategy for exploitation of anti-tumor agents. VPA might markedly increase the sensitivity of TKI-resistant lung adenocarcinoma cells to Erlotinib, thus reversing the acquired TKI-resistance of cancer cells and raising VPA as a potential agent for TKI-resistant lung cancer therapy.

  6. Valproic acid, an inhibitor of class I histone deacetylases, reverses acquired Erlotinib-resistance of lung adenocarcinoma cells: a Connectivity Mapping analysis and an experimental study

    PubMed Central

    Zhuo, Wenlei; Zhang, Liang; Zhu, Yi; Xie, Qichao; Zhu, Bo; Chen, Zhengtang

    2015-01-01

    Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKI) have been used as a powerful targeting therapeutic agent for treatment of lung adenocarcinoma for years. Nevertheless, the efficacy of TKI was hampered by the appearance of acquired TKI-resistance. In the present study, we aimed to search, predict, and screen the agents that can overcome the acquired TKI-resistance of lung adenocarcinoma by using the expression profiles of differentially expressed genes (DEGs) and Connectivity map (CMAP). The profiles of DEGs were obtained by searching GEO microarray database, and then, they were submitted to CMAP for analysis in order to predict and screen the agent that might reverse the TKI-resistance of lung cancer cells. Next, the effects of the selected agent on TKI-resistant cancer cells were tested and the possible signaling pathways were also evaluated. As a result, valproic acid (VPA) was selected. Then, we used a low-concentration of VPA that has little effect on the cell growth for analysis. Interestingly, the results showed that treatment with a combination of VPA and Erlotinib significantly led to a decrease in cell viability and an increase in cell apoptosis for TKI-resistant HCC827-ER cells, relative to those treated with VPA or Erlotinib alone. Further experiments confirmed that inhibition of MAPK and AKT might be involved in this process. Analyzing the DEGs through the CMAP is a good strategy for exploitation of anti-tumor agents. VPA might markedly increase the sensitivity of TKI-resistant lung adenocarcinoma cells to Erlotinib, thus reversing the acquired TKI-resistance of cancer cells and raising VPA as a potential agent for TKI-resistant lung cancer therapy. PMID:26328250

  7. Valproic acid, an inhibitor of class I histone deacetylases, reverses acquired Erlotinib-resistance of lung adenocarcinoma cells: a Connectivity Mapping analysis and an experimental study.

    PubMed

    Zhuo, Wenlei; Zhang, Liang; Zhu, Yi; Xie, Qichao; Zhu, Bo; Chen, Zhengtang

    2015-01-01

    Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKI) have been used as a powerful targeting therapeutic agent for treatment of lung adenocarcinoma for years. Nevertheless, the efficacy of TKI was hampered by the appearance of acquired TKI-resistance. In the present study, we aimed to search, predict, and screen the agents that can overcome the acquired TKI-resistance of lung adenocarcinoma by using the expression profiles of differentially expressed genes (DEGs) and Connectivity map (CMAP). The profiles of DEGs were obtained by searching GEO microarray database, and then, they were submitted to CMAP for analysis in order to predict and screen the agent that might reverse the TKI-resistance of lung cancer cells. Next, the effects of the selected agent on TKI-resistant cancer cells were tested and the possible signaling pathways were also evaluated. As a result, valproic acid (VPA) was selected. Then, we used a low-concentration of VPA that has little effect on the cell growth for analysis. Interestingly, the results showed that treatment with a combination of VPA and Erlotinib significantly led to a decrease in cell viability and an increase in cell apoptosis for TKI-resistant HCC827-ER cells, relative to those treated with VPA or Erlotinib alone. Further experiments confirmed that inhibition of MAPK and AKT might be involved in this process. Analyzing the DEGs through the CMAP is a good strategy for exploitation of anti-tumor agents. VPA might markedly increase the sensitivity of TKI-resistant lung adenocarcinoma cells to Erlotinib, thus reversing the acquired TKI-resistance of cancer cells and raising VPA as a potential agent for TKI-resistant lung cancer therapy. PMID:26328250

  8. Integrated genomic approaches identify upregulation of SCRN1 as a novel mechanism associated with acquired resistance to erlotinib in PC9 cells harboring oncogenic EGFR mutation

    PubMed Central

    Kim, Nayoung; Cho, Ahye; Watanabe, Hideo; Choi, Yoon-La; Aziz, Meraj; Kassner, Michelle; Joung, Je-Gun; Park, Angela KJ; Francis, Joshua M.; Bae, Joon Seol; Ahn, Soo-min; Kim, Kyoung-Mee; Park, Joon Oh; Park, Woong-Yang; Ahn, Myung-Ju; Park, Keunchil; Koo, Jaehyung; Yin, Hongwei Holly; Cho, Jeonghee

    2016-01-01

    Therapies targeting the tyrosine kinase activity of Epidermal Growth Factor Receptor (EGFR) have been proven to be effective in treating a subset of non-small cell lung cancer (NSCLC) patients harboring activating EGFR mutations. Inevitably these patients develop resistance to the EGFR-targeted tyrosine kinase inhibitors (TKIs). Here, we performed integrated genomic analyses using an in vitro system to uncover alternative genomic mechanisms responsible for acquired resistance to EGFR-TKIs. Specifically, we identified 80 genes whose expression is significantly increased in the erlotinib-resistant clones. RNAi-based systematic synthetic lethal screening of these candidate genes revealed that suppression of one upregulated transcript, SCRN1, a secernin family member, restores sensitivity to erlotinib by enhancing inhibition of PI3K/AKT signaling pathway. Furthermore, immunohistochemical analysis revealed increased levels of SCRN1 in 5 of 11 lung tumor specimens from EGFR-TKIs resistant patients. Taken together, we propose that upregulation of SCRN1 is an additional mechanism associated with acquired resistance to EGFR-TKIs and that its suppression serves as a novel therapeutic strategy to overcome drug resistance in these patients. PMID:26883194

  9. Decreased glutathione biosynthesis contributes to EGFR T790M-driven erlotinib resistance in non-small cell lung cancer

    PubMed Central

    Li, Hongde; Stokes, William; Chater, Emily; Roy, Rajat; de Bruin, Elza; Hu, Yili; Liu, Zhigang; Smit, Egbert F; Heynen, Guus JJE; Downward, Julian; Seckl, Michael J; Wang, Yulan; Tang, Huiru; Pardo, Olivier E

    2016-01-01

    Epidermal growth factor receptor (EGFR) inhibitors such as erlotinib are novel effective agents in the treatment of EGFR-driven lung cancer, but their clinical impact is often impaired by acquired drug resistance through the secondary T790M EGFR mutation. To overcome this problem, we analysed the metabonomic differences between two independent pairs of erlotinib-sensitive/resistant cells and discovered that glutathione (GSH) levels were significantly reduced in T790M EGFR cells. We also found that increasing GSH levels in erlotinib-resistant cells re-sensitised them, whereas reducing GSH levels in erlotinib-sensitive cells made them resistant. Decreased transcription of the GSH-synthesising enzymes (GCLC and GSS) due to the inhibition of NRF2 was responsible for low GSH levels in resistant cells that was directly linked to the T790M mutation. T790M EGFR clinical samples also showed decreased expression of these key enzymes; increasing intra-tumoural GSH levels with a small-molecule GST inhibitor re-sensitised resistant tumours to erlotinib in mice. Thus, we identified a new resistance pathway controlled by EGFR T790M and a therapeutic strategy to tackle this problem in the clinic. PMID:27721983

  10. Adaptive and Acquired Resistance to EGFR Inhibitors Converge on the MAPK Pathway

    PubMed Central

    Ma, Pengfei; Fu, Yujie; Chen, Minjiang; Jing, Ying; Wu, Jie; Li, Ke; Shen, Ying; Gao, Jian-Xin; Wang, Mengzhao; Zhao, Xiaojing; Zhuang, Guanglei

    2016-01-01

    Both adaptive and acquired resistance significantly limits the efficacy of the epidermal growth factor receptor (EGFR) kinase inhibitors. However, the distinct or common mechanisms of adaptive and acquired resistance have not been fully characterized. Here, through systematic modeling of erlotinib resistance in lung cancer, we found that feedback reactivation of MAPK signaling following erlotinib treatment, which was dependent on the MET receptor, contributed to the adaptive resistance of EGFR inhibitors. Interestingly, acquired resistance to erlotinib was also associated with the MAPK pathway activation as a result of CRAF or NRAS amplification. Consequently, combined inhibition of EGFR and MAPK impeded the development of both adaptive and acquired resistance. These observations demonstrate that adaptive and acquired resistance to EGFR inhibitors can converge on the same pathway and credential cotargeting EGFR and MAPK as a promising therapeutic approach in EGFR mutant tumors. PMID:27279914

  11. Systemic Acquired Resistance

    PubMed Central

    2006-01-01

    Upon infection with necrotizing pathogens many plants develop an enhanced resistance to further pathogen attack also in the uninoculated organs. This type of enhanced resistance is referred to as systemic acquired resistance (SAR). In the SAR state, plants are primed (sensitized) to more quickly and more effectively activate defense responses the second time they encounter pathogen attack. Since SAR depends on the ability to access past experience, acquired disease resistance is a paradigm for the existence of a form of “plant memory”. Although the phenomenon has been known since the beginning of the 20th century, major progress in the understanding of SAR was made over the past sixteen years. This review covers the current knowledge of molecular, biochemical and physiological mechanisms that are associated with SAR. PMID:19521483

  12. Erlotinib resistance in mouse models of epidermal growth factor receptor-induced lung adenocarcinoma

    PubMed Central

    Politi, Katerina; Fan, Pang-Dian; Shen, Ronglai; Zakowski, Maureen; Varmus, Harold

    2010-01-01

    SUMMARY Seventy-five percent of lung adenocarcinomas with epidermal growth factor receptor (EGFR) mutations respond to treatment with the tyrosine kinase inhibitors (TKIs) gefitinib and erlotinib; however, drug-resistant tumors eventually emerge. In 60% of cases, resistant tumors carry a secondary mutation in EGFR (T790M), amplification of MET, or both. Here, we describe the establishment of erlotinib resistance in lung tumors, which were induced by mutant EGFR, in transgenic mice after multiple cycles of drug treatment; we detect the T790M mutation in five out of 24 tumors or Met amplification in one out of 11 tumors in these mice. This preclinical mouse model, therefore, recapitulates the molecular changes responsible for resistance to TKIs in human tumors and holds promise for the discovery of additional mechanisms of drug resistance in lung cancer. PMID:20007486

  13. Erlotinib resistance in mouse models of epidermal growth factor receptor-induced lung adenocarcinoma.

    PubMed

    Politi, Katerina; Fan, Pang-Dian; Shen, Ronglai; Zakowski, Maureen; Varmus, Harold

    2010-01-01

    Seventy-five percent of lung adenocarcinomas with epidermal growth factor receptor (EGFR) mutations respond to treatment with the tyrosine kinase inhibitors (TKIs) gefitinib and erlotinib; however, drug-resistant tumors eventually emerge. In 60% of cases, resistant tumors carry a secondary mutation in EGFR (T790M), amplification of MET, or both. Here, we describe the establishment of erlotinib resistance in lung tumors, which were induced by mutant EGFR, in transgenic mice after multiple cycles of drug treatment; we detect the T790M mutation in five out of 24 tumors or Met amplification in one out of 11 tumors in these mice. This preclinical mouse model, therefore, recapitulates the molecular changes responsible for resistance to TKIs in human tumors and holds promise for the discovery of additional mechanisms of drug resistance in lung cancer.

  14. JAK2 inhibitor TG101348 overcomes erlotinib-resistance in non-small cell lung carcinoma cells with mutated EGF receptor.

    PubMed

    Zhang, Fu-quan; Yang, Wen-tao; Duan, Shan-zhou; Xia, Ying-chen; Zhu, Rong-ying; Chen, Yong-bing

    2015-06-10

    Non-small cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) mutations are responsive to EGFR-tyrosine kinase inhibitor (EGFR-TKI). However, NSCLC patients with secondary somatic EGFR mutations are resistant to EGFR-TKI treatment. In this study, we investigated the effect of TG101348 (a JAK2 inhibitor) on the tumor growth of erlotinib-resistant NSCLC cells. Cell proliferation, apoptosis, gene expression and tumor growth were evaluated by diphenyltetrazolium bromide (MTT) assay, flow cytometry, terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling (TUNEL) staining, Western Blot and a xenograft mouse model, respectively. Results showed that erlotinib had a stronger impact on the induction of apoptosis in erlotinib-sensitive PC-9 cells but had a weaker effect on erlotinib-resistant H1975 and H1650 cells than TG101348. TG101348 significantly enhanced the cytotoxicity of erlotinib to erlotinib-resistant NSCLC cells, stimulated erlotinib-induced apoptosis and downregulated the expressions of EGFR, p-EGFR, p-STAT3, Bcl-xL and survivin in erlotinib-resistant NSCLC cells. Moreover, the combined treatment of TG101348 and erlotinib induced apoptosis, inhibited the activation of p-EGFR and p-STAT3, and inhibited tumor growth of erlotinib-resistant NSCLC cells in vivo. Our results indicate that TG101348 is a potential adjuvant for NSCLC patients during erlotinib treatment.

  15. EPHA2 Blockade Overcomes Acquired Resistance to EGFR Kinase Inhibitors in Lung Cancer.

    PubMed

    Amato, Katherine R; Wang, Shan; Tan, Li; Hastings, Andrew K; Song, Wenqiang; Lovly, Christine M; Meador, Catherine B; Ye, Fei; Lu, Pengcheng; Balko, Justin M; Colvin, Daniel C; Cates, Justin M; Pao, William; Gray, Nathanael S; Chen, Jin

    2016-01-15

    Despite the success of treating EGFR-mutant lung cancer patients with EGFR tyrosine kinase inhibitors (TKI), all patients eventually acquire resistance to these therapies. Although various resistance mechanisms have been described, there are currently no FDA-approved therapies that target alternative mechanisms to treat lung tumors with acquired resistance to first-line EGFR TKI agents. Here we found that EPHA2 is overexpressed in EGFR TKI-resistant tumor cells. Loss of EPHA2 reduced the viability of erlotinib-resistant tumor cells harboring EGFR(T790M) mutations in vitro and inhibited tumor growth and progression in an inducible EGFR(L858R+T790M)-mutant lung cancer model in vivo. Targeting EPHA2 in erlotinib-resistant cells decreased S6K1-mediated phosphorylation of cell death agonist BAD, resulting in reduced tumor cell proliferation and increased apoptosis. Furthermore, pharmacologic inhibition of EPHA2 by the small-molecule inhibitor ALW-II-41-27 decreased both survival and proliferation of erlotinib-resistant tumor cells and inhibited tumor growth in vivo. ALW-II-41-27 was also effective in decreasing viability of cells with acquired resistance to the third-generation EGFR TKI AZD9291. Collectively, these data define a role for EPHA2 in the maintenance of cell survival of TKI-resistant, EGFR-mutant lung cancer and indicate that EPHA2 may serve as a useful therapeutic target in TKI-resistant tumors.

  16. EPHA2 Blockade Overcomes Acquired Resistance to EGFR Kinase Inhibitors in Lung Cancer.

    PubMed

    Amato, Katherine R; Wang, Shan; Tan, Li; Hastings, Andrew K; Song, Wenqiang; Lovly, Christine M; Meador, Catherine B; Ye, Fei; Lu, Pengcheng; Balko, Justin M; Colvin, Daniel C; Cates, Justin M; Pao, William; Gray, Nathanael S; Chen, Jin

    2016-01-15

    Despite the success of treating EGFR-mutant lung cancer patients with EGFR tyrosine kinase inhibitors (TKI), all patients eventually acquire resistance to these therapies. Although various resistance mechanisms have been described, there are currently no FDA-approved therapies that target alternative mechanisms to treat lung tumors with acquired resistance to first-line EGFR TKI agents. Here we found that EPHA2 is overexpressed in EGFR TKI-resistant tumor cells. Loss of EPHA2 reduced the viability of erlotinib-resistant tumor cells harboring EGFR(T790M) mutations in vitro and inhibited tumor growth and progression in an inducible EGFR(L858R+T790M)-mutant lung cancer model in vivo. Targeting EPHA2 in erlotinib-resistant cells decreased S6K1-mediated phosphorylation of cell death agonist BAD, resulting in reduced tumor cell proliferation and increased apoptosis. Furthermore, pharmacologic inhibition of EPHA2 by the small-molecule inhibitor ALW-II-41-27 decreased both survival and proliferation of erlotinib-resistant tumor cells and inhibited tumor growth in vivo. ALW-II-41-27 was also effective in decreasing viability of cells with acquired resistance to the third-generation EGFR TKI AZD9291. Collectively, these data define a role for EPHA2 in the maintenance of cell survival of TKI-resistant, EGFR-mutant lung cancer and indicate that EPHA2 may serve as a useful therapeutic target in TKI-resistant tumors. PMID:26744526

  17. Silibinin suppresses EMT-driven erlotinib resistance by reversing the high miR-21/low miR-200c signature in vivo

    PubMed Central

    Cufí, Sílvia; Bonavia, Rosa; Vazquez-Martin, Alejandro; Oliveras-Ferraros, Cristina; Corominas-Faja, Bruna; Cuyàs, Elisabet; Martin-Castillo, Begoña; Barrajón-Catalán, Enrique; Visa, Joana; Segura-Carretero, Antonio; Joven, Jorge; Bosch-Barrera, Joaquim; Micol, Vicente; Menendez, Javier A.

    2013-01-01

    The flavolignan silibinin was studied for its ability to restore drug sensitivity to EGFR-mutant NSCLC xenografts with epithelial-to-mesenchymal transition (EMT)-driven resistance to erlotinib. As a single agent, silibinin significantly decreased the tumor volumes of erlotinib-refractory NSCLC xenografts by approximately 50%. Furthermore, the complete abrogation of tumor growth was observed with the co-treatment of erlotinib and silibinin. Silibinin fully reversed the EMT-related high miR-21/low miR-200c microRNA signature and repressed the mesenchymal markers SNAIL, ZEB, and N-cadherin observed in erlotinib-refractory tumors. Silibinin was sufficient to fully activate a reciprocal mesenchymal-to-epithelial transition (MET) in erlotinib-refractory cells and prevent the highly migratogenic phenotype of erlotinib-resistant NSCLC cells. Given that the various mechanisms of resistance to erlotinib result from EMT, regardless of the EGFR mutation status, a water-soluble, silibinin-rich milk thistle extract might be a suitable candidate therapy for upcoming clinical trials aimed at preventing or reversing NSCLC progression following erlotinib treatment. PMID:23963283

  18. The autophagy inhibitor chloroquine overcomes the innate resistance to erlotinib of non-small cell lung cancer cells with wild-type EGFR

    PubMed Central

    Zou, Yiyu; Ling, Yi-He; Sironi, Juan; Schwartz, Edward L.; Perez-Soler, Roman; Piperdi, Bilal

    2013-01-01

    Introduction The EGFR inhibitor erlotinib is much less effective in NSCLC tumors with wild-type EGFR than in tumors with activating EGFR mutations. Autophagy is a tightly regulated lysosomal self-digestion process that may alternatively promote cell survival or type II cell death. This study assessed the role of autophagy in erlotinib-mediated cytotoxicity. Methods We used wild-type EGFR erlotinib-sensitive and -resistant NSCLC cell lines to determine if inhibiting autophagy by a therapeutic agent potentiated the antitumor activity of erlotinib in vitro and in vivo. Results Erlotinib at a clinically relevant concentration (2 μM) induced autophagy in NSCLC cells with wild type EGFR, and the degree of induction was greater in resistant than in sensitive cells, suggesting that autophagy is cytoprotective. This was confirmed by knockdown of the autophagy-related gene Atg-5 and by using the autophagy inhibitor chloroquine (CQ), both of which increased the cytotoxicity of erlotinib. The synergistic activity of CQ was not due to the potentiation of erlotinib’s effects on autophagy, cell cycle arrest, inhibition of EGF receptor, or the inhibition of signaling downstream of the EGFR. Rather CQ markedly activated apoptosis in the cells. The ability of CQ to potentiate the antitumor activity of erlotinib was also seen in mice bearing NSCLC tumor xenografts. Conclusions The ability to adapt to anti-EGFR therapy by triggering autophagy may be a key determinant of resistance to erlotinib in wild-type EGFR NSCLC. Inhibition of autophagy by CQ represents a novel strategy to broaden the spectrum of erlotinib efficacy in wild-type EGFR NSCLC tumors. PMID:23575415

  19. Acquired resistance of non-small cell lung cancer to epidermal growth factor receptor tyrosine kinase inhibitors.

    PubMed

    Nurwidya, Fariz; Takahashi, Fumiyuki; Murakami, Akiko; Kobayashi, Isao; Kato, Motoyasu; Shukuya, Takehito; Tajima, Ken; Shimada, Naoko; Takahashi, Kazuhisa

    2014-03-01

    Activation of epidermal growth factor receptor (EGFR) triggers anti-apoptotic signaling, proliferation, angiogenesis, invasion, metastasis, and drug resistance, which leads to development and progression of human epithelial cancers, including non-small cell lung cancer (NSCLC). Inhibition of EGFR by tyrosine kinase inhibitors such as gefitinib and erlotinib has provided a new hope for the cure of NSCLC patients. However, acquired resistance to gefitinib and erlotinib via EGFR-mutant NSCLC has occurred through various molecular mechanisms such as T790M secondary mutation, MET amplification, hepatocyte growth factor (HGF) overexpression, PTEN downregulation, epithelial-mesenchymal transition (EMT), and other mechanisms. This review will discuss the biology of receptor tyrosine kinase inhibition and focus on the molecular mechanisms of acquired resistance to tyrosine kinase inhibitors of EGFR-mutant NSCLC.

  20. Acquired Resistance to EGFR Kinase Inhibitors Associated with a Novel T854A Mutation in a Patient with EGFR-Mutant Lung Adenocarcinoma

    PubMed Central

    Bean, James; Riely, Gregory J.; Balak, Marissa; Marks, Jenifer L.; Ladanyi, Marc; Miller, Vincent A.; Pao, William

    2008-01-01

    Purpose Somatic mutations in the tyrosine kinase domain of EGFR are associated with sensitivity of lung adenocarcinomas to the EGFR tyrosine kinase inhibitors (TKIs), gefitinib and erlotinib. Acquired drug resistance is frequently associated with a secondary somatic mutation that leads to substitution of methionine for threonine at position 790 (T790M). We aimed to identify additional second-site alterations associated with acquired resistance. Experimental Design Tumor samples were obtained from 48 patients with acquired resistance. Tumor cell DNA was analyzed for EGFR kinase domain mutations. Molecular analyses were then performed to characterize biological properties of a novel mutant EGFR allele. Results A previously unreported mutation in exon 21 of EGFR, which leads to substitution of alanine for threonine at position 854 (T854A), was identified in one patient with a drug-sensitive EGFR L858R-mutant lung adenocarcinoma after long-term treatment with TKIs. The T854A mutation was not detected in a pretreatment tumor sample. Crystal structure analyses of EGFR suggest that the T854 side chain is within contact distance of gefitinib and erlotinib. Surrogate kinase assays demonstrate that the EGFR T854A mutation abrogates inhibition of tyrosine phosphorylation by erlotinib. Such resistance appears to be overcome by a new irreversible dual EGFR/HER2 inhibitor, BIBW 2992. Conclusions The T854A mutation is the second reported second-site acquired resistance mutation that is within contact distance of gefitinib and erlotinib. These data suggest that acquired resistance to ATP-mimetic EGFR kinase inhibitors may often be associated with amino acid substitutions that alter drug contact residues in the EGFR ATP-binding pocket. PMID:19010870

  1. Acquired Antibiotic Resistance Genes: An Overview

    PubMed Central

    van Hoek, Angela H. A. M.; Mevius, Dik; Guerra, Beatriz; Mullany, Peter; Roberts, Adam Paul; Aarts, Henk J. M.

    2011-01-01

    In this review an overview is given on antibiotic resistance (AR) mechanisms with special attentions to the AR genes described so far preceded by a short introduction on the discovery and mode of action of the different classes of antibiotics. As this review is only dealing with acquired resistance, attention is also paid to mobile genetic elements such as plasmids, transposons, and integrons, which are associated with AR genes, and involved in the dispersal of antimicrobial determinants between different bacteria. PMID:22046172

  2. Signal regulators of systemic acquired resistance

    PubMed Central

    Gao, Qing-Ming; Zhu, Shifeng; Kachroo, Pradeep; Kachroo, Aardra

    2015-01-01

    Salicylic acid (SA) is an important phytohormone that plays a vital role in a number of physiological responses, including plant defense. The last two decades have witnessed a number of breakthroughs related to biosynthesis, transport, perception and signaling mediated by SA. These findings demonstrate that SA plays a crictical role in both local and systemic defense responses. Systemic acquired resistance (SAR) is one such SA-dependent response. SAR is a long distance signaling mechanism that provides broad spectrum and long-lasting resistance to secondary infections throughout the plant. This unique feature makes SAR a highly desirable trait in crop production. This review summarizes the recent advances in the role of SA in SAR and discusses its relationship to other SAR inducers. PMID:25918514

  3. MECHANISMS OF ACQUIRED RESISTANCE IN MOUSE TYPHOID

    PubMed Central

    Blanden, R. V.; Mackaness, G. B.; Collins, F. M.

    1966-01-01

    Experiments in vitro comparing normal mouse peritoneal macrophages with cells from Salmonella typhimurium-infected mice have shown that the "immune" macrophages have conspicuously enhanced microbicidal properties. Whereas normal macrophages could inactivate only 50 to 60% of intracellular S. typhimurium pretreated with immune serum, cells from infected animals killed virtually all ingested organisms and did so at an accelerated rate. Macrophages from Listeria monocytogenes-infected mice were shown to possess similarly enhanced microbicidal activity against S. typhimurium. Furthermore, the growth of S. typhimurium in the liver and spleen was more effectively restricted in Listeria-infected mice than in animals vaccinated with heat-killed S. typhimurium, even though the Listeria-infected animals possessed no demonstrable cross-reacting antibody to S. typhimurium. The lack of resistance in the mice vaccinated with heat-killed organisms could not be attributed to any deficiency of humoral factors, since the serum from these animals was as effective at promoting phagocytosis and killing by macrophages as serum from actively infected (and demonstrably resistant) mice. Conversely, Salmonella-infected mice were totally resistant to intravenous challenge with L. monocytogenes. The level of resistance in individual animals was related to the numbers of residual Salmonellae remaining in the tissues; mice with heavier residual infections being the more resistant. Specific antiserum from mice vaccinated with heat-killed S. typhimurium was found to be significantly protective only when the intraperitoneal route of challenge was employed. The foregoing studies have been interpreted to mean that enhancement of the microbicidal ability of macrophages is the mechanism of major importance in acquired resistance to S. typhimurium infection in mice. PMID:4958757

  4. Mechanisms of polymyxin resistance: acquired and intrinsic resistance in bacteria

    PubMed Central

    Olaitan, Abiola O.; Morand, Serge; Rolain, Jean-Marc

    2014-01-01

    Polymyxins are polycationic antimicrobial peptides that are currently the last-resort antibiotics for the treatment of multidrug-resistant, Gram-negative bacterial infections. The reintroduction of polymyxins for antimicrobial therapy has been followed by an increase in reports of resistance among Gram-negative bacteria. Some bacteria, such as Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii, develop resistance to polymyxins in a process referred to as acquired resistance, whereas other bacteria, such as Proteus spp., Serratia spp., and Burkholderia spp., are naturally resistant to these drugs. Reports of polymyxin resistance in clinical isolates have recently increased, including acquired and intrinsically resistant pathogens. This increase is considered a serious issue, prompting concern due to the low number of currently available effective antibiotics. This review summarizes current knowledge concerning the different strategies bacteria employ to resist the activities of polymyxins. Gram-negative bacteria employ several strategies to protect themselves from polymyxin antibiotics (polymyxin B and colistin), including a variety of lipopolysaccharide (LPS) modifications, such as modifications of lipid A with phosphoethanolamine and 4-amino-4-deoxy-L-arabinose, in addition to the use of efflux pumps, the formation of capsules and overexpression of the outer membrane protein OprH, which are all effectively regulated at the molecular level. The increased understanding of these mechanisms is extremely vital and timely to facilitate studies of antimicrobial peptides and find new potential drugs targeting clinically relevant Gram-negative bacteria. PMID:25505462

  5. Mechanisms of polymyxin resistance: acquired and intrinsic resistance in bacteria.

    PubMed

    Olaitan, Abiola O; Morand, Serge; Rolain, Jean-Marc

    2014-01-01

    Polymyxins are polycationic antimicrobial peptides that are currently the last-resort antibiotics for the treatment of multidrug-resistant, Gram-negative bacterial infections. The reintroduction of polymyxins for antimicrobial therapy has been followed by an increase in reports of resistance among Gram-negative bacteria. Some bacteria, such as Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii, develop resistance to polymyxins in a process referred to as acquired resistance, whereas other bacteria, such as Proteus spp., Serratia spp., and Burkholderia spp., are naturally resistant to these drugs. Reports of polymyxin resistance in clinical isolates have recently increased, including acquired and intrinsically resistant pathogens. This increase is considered a serious issue, prompting concern due to the low number of currently available effective antibiotics. This review summarizes current knowledge concerning the different strategies bacteria employ to resist the activities of polymyxins. Gram-negative bacteria employ several strategies to protect themselves from polymyxin antibiotics (polymyxin B and colistin), including a variety of lipopolysaccharide (LPS) modifications, such as modifications of lipid A with phosphoethanolamine and 4-amino-4-deoxy-L-arabinose, in addition to the use of efflux pumps, the formation of capsules and overexpression of the outer membrane protein OprH, which are all effectively regulated at the molecular level. The increased understanding of these mechanisms is extremely vital and timely to facilitate studies of antimicrobial peptides and find new potential drugs targeting clinically relevant Gram-negative bacteria.

  6. Phase II trial of everolimus and erlotinib in patients with platinum-resistant recurrent and/or metastatic head and neck squamous cell carcinoma

    PubMed Central

    Massarelli, E.; Lin, H.; Ginsberg, L. E.; Tran, H. T.; Lee, J. J.; Canales, J. R.; Williams, M. D.; Blumenschein, G. R.; Lu, C.; Heymach, J. V.; Kies, M. S.; Papadimitrakopoulou, V.

    2015-01-01

    Background Enhanced phosphoinositide 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway is one of the key adaptive changes accounting for epidermal growth factor receptor (EGFR) inhibitor-resistant growth in head and neck squamous cell carcinoma (HNSCC). We designed a phase II clinical trial of EGFR tyrosine kinase inhibitor (TKI), erlotinib, in association with the mTOR inhibitor, everolimus, based on the hypothesis that the downstream effects of Akt through inhibition of mTOR may enhance the effectiveness of the EGFR-TKI in patients with recurrent/metastatic HNSCC. Patients and methods Patients with histologically or cytologically confirmed platinum-resistant HNSCC received everolimus 5 mg and erlotinib 150 mg daily orally until disease progression, intolerable toxicity, investigator or patient decision. Cytokines and angiogenic factors profile, limited mutation analysis and p16 immunohistochemistry status were included in the biomarker analysis. Results Of the 35 assessable patients, 3 (8%) achieved partial response at 4 weeks, 1 confirmed at 12 weeks; overall response rate at 12 weeks was 2.8%. Twenty-seven (77%) patients achieved disease stabilization at 4 weeks, 11 (31%) confirmed at 12 weeks. Twelve-week progression-free survival (PFS) was 49%, median PFS 11.9 weeks and median overall survival (OS) 10.25 months. High neutrophil gelatinase lipocalin (P = 0.01) and vascular endothelial growth factor (VEGF) (P = 0.04) plasma levels were significantly associated with worse OS. Conclusions The combination of erlotinib and everolimus did not show significant benefit in unselected patients with platinum-resistant metastatic HNSCC despite a manageable toxicity profile. Markers of tumor invasion and hypoxia identify a group of patients with particularly poor prognosis. Clinical trial number NCT00942734. PMID:26025965

  7. Acquired resistance of pancreatic cancer cells to treatment with gemcitabine and HER-inhibitors is accompanied by increased sensitivity to STAT3 inhibition

    PubMed Central

    IOANNOU, NIKOLAOS; SEDDON, ALAN M.; DALGLEISH, ANGUS; MACKINTOSH, DAVID; SOLCA, FLAVIO; MODJTAHEDI, HELMOUT

    2016-01-01

    Drug-resistance is a major contributing factor for the poor prognosis in patients with pancreatic cancer. We have shown previously that the irreversible ErbB family blocker afatinib, is more effective than the reversible EGFR tyrosine kinase inhibitor erlotinib in inhibiting the growth of human pancreatic cancer cells. The aim of this study was to develop human pancreatic cancer cell (BxPc3) variants with acquired resistance to treatment with gemcitabine, afatinib, or erlotinib, and to investigate the molecular changes that accompany the acquisition of a drug-resistant phenotype. We also investigated the therapeutic potential of various agents in the treatment of such drug-resistant variants. Three variant forms of BxPc3 cells with acquired resistance to gemcitabine (BxPc3GEM), afatinib (BxPc3AFR) or erlotinib (BxPc3OSIR) were developed following treatment with increasing doses of such drugs. The expression level, mutational and phosphorylation status of various growth factor receptors and downstream cell signaling molecules were determined by FACS, human phopsho-RTK array, and western blot analysis while the sulforhodamine B assay was used for determining the effect of various agents on the growth of such tumours. We found that all three BxPc3 variants with acquired resistance to gemcitabine (BxPc3GEM), afatinib (BxPc3AFR) or erlotinib (BxPc3OSIR) also become less sensitive to treatment with the two other agents. Acquisition of resistance to these agents was accompanied by upregulation of p-c-MET, p-STAT3, CD44, increased autocrine production of EGFR ligand amphiregulin and differential activation status of EGFR tyrosine residues as well as downregulation of total and p-SRC. Of all therapeutic interventions examined, including the addition of an anti-EGFR antibody ICR62, an anti-CD44 monoclonal antibody, and of STAT3 or c-MET inhibitors, only treatment with the STAT3 inhibitor Stattic produced a higher growth inhibitory effect in all three drug-resistant variants

  8. The molecular mechanisms of acquired proteasome inhibitor resistance

    PubMed Central

    Kale, Andrew J.; Moore, Bradley S.

    2012-01-01

    The development of proteasome inhibitors (PIs) has transformed the treatment of multiple myeloma and mantle cell lymphoma. To date, two PIs have been FDA approved, the boronate peptide bortezomib and, most recently, the epoxyketone peptide carfilzomib. However, intrinsic and acquired resistance to PIs, for which the underlying mechanisms are poorly understood, may limit their efficacy. In this perspective, we discuss recent advances in the molecular understanding of PI resistance through acquired bortezomib resistance in human cell lines to evolved saliniosporamide A (marizomib) resistance in nature. Resistance mechanisms discussed include the upregulation of proteasome subunits and mutations of the catalytic β-subunits. Additionally, we explore potential strategies to overcome PI resistance. PMID:22978849

  9. Acquired Drug Resistance in Mycobacterium tuberculosis and Poor Outcomes among Patients with Multidrug-Resistant Tuberculosis

    PubMed Central

    Kipiani, Maia; Mirtskhulava, Veriko; Tukvadze, Nestani; Magee, Matthew J.; Blumberg, Henry M.

    2015-01-01

    Rates and risk factors for acquired drug resistance and association with outcomes among patients with multidrug-resistant tuberculosis (MDR TB) are not well defined. In an MDR TB cohort from the country of Georgia, drug susceptibility testing for second-line drugs (SLDs) was performed at baseline and every third month. Acquired resistance was defined as any SLD whose status changed from susceptible at baseline to resistant at follow-up. Among 141 patients, acquired resistance in Mycobacterium tuberculosis was observed in 19 (14%); prevalence was 9.1% for ofloxacin and 9.8% for capreomycin or kanamycin. Baseline cavitary disease and resistance to >6 drugs were associated with acquired resistance. Patients with M. tuberculosis that had acquired resistance were at significantly increased risk for poor treatment outcome compared with patients without these isolates (89% vs. 36%; p<0.01). Acquired resistance occurs commonly among patients with MDR TB and impedes successful treatment outcomes. PMID:25993036

  10. Detecting mechanisms of acquired BRAF inhibitor resistance in melanoma.

    PubMed

    Lo, Roger S; Shi, Hubing

    2014-01-01

    (V600)BRAF mutation was identified as an ideal target for clinical therapy due to its indispensable roles in supporting melanoma initiation and progression. Despite the fact that BRAF inhibitors (BRAFi) can elicit anti-tumor responses in the majority of treated patients and confer overall survival benefits, acquired drug resistance is a formidable obstacle to long-term management of the disease. Several aberrant events including RTK upregulation, NRAS mutation, mutant BRAF amplification or alternative splicing, and MEK mutation have been reported as acquired BRAFi resistance mechanisms. Clinially, detection of these resistance mechanisms help understand drug response patterns and help guide combinatorial therapeutic strategies. Therefore, quick and accurate diagnosis of the resistant mechanisms in tumor biopsies has become an important starting point for personalized therapy. In this chapter, we review the major acquired BRAFi resistance mechanisms, highlight their therapeutic implications, and provide the diagnostic methods from clinical samples.

  11. A Research-Inspired Laboratory Sequence Investigating Acquired Drug Resistance

    ERIC Educational Resources Information Center

    Taylor, Elizabeth Vogel; Fortune, Jennifer A.; Drennan, Catherine L.

    2010-01-01

    Here, we present a six-session laboratory exercise designed to introduce students to standard biochemical techniques in the context of investigating a high impact research topic, acquired resistance to the cancer drug Gleevec. Students express a Gleevec-resistant mutant of the Abelson tyrosine kinase domain, the active domain of an oncogenic…

  12. Acquired inducible antimicrobial resistance in Gram-positive bacteria

    PubMed Central

    Chancey, Scott T; Zähner, Dorothea; Stephens, David S

    2012-01-01

    A major contributor to the emergence of antibiotic resistance in Gram-positive bacterial pathogens is the expansion of acquired, inducible genetic elements. Although acquired, inducible antibiotic resistance is not new, the interest in its molecular basis has been accelerated by the widening distribution and often ‘silent’ spread of the elements responsible, the diagnostic challenges of such resistance and the mounting limitations of available agents to treat Gram-positive infections. Acquired, inducible antibiotic resistance elements belong to the accessory genome of a species and are horizontally acquired by transformation/recombination or through the transfer of mobile DNA elements. The two key, but mechanistically very different, induction mechanisms are: ribosome-sensed induction, characteristic of the macrolide–lincosamide–streptogramin B antibiotics and tetracycline resistance, leading to ribosomal modifications or efflux pump activation; and resistance by cell surface-associated sensing of β-lactams (e.g., oxacillin), glycopeptides (e.g., vancomycin) and the polypeptide bacitracin, leading to drug inactivation or resistance due to cell wall alterations. PMID:22913355

  13. Targets for Combating the Evolution of Acquired Antibiotic Resistance.

    PubMed

    Culyba, Matthew J; Mo, Charlie Y; Kohli, Rahul M

    2015-06-16

    Bacteria possess a remarkable ability to rapidly adapt and evolve in response to antibiotics. Acquired antibiotic resistance can arise by multiple mechanisms but commonly involves altering the target site of the drug, enzymatically inactivating the drug, or preventing the drug from accessing its target. These mechanisms involve new genetic changes in the pathogen leading to heritable resistance. This recognition underscores the importance of understanding how such genetic changes can arise. Here, we review recent advances in our understanding of the processes that contribute to the evolution of antibiotic resistance, with a particular focus on hypermutation mediated by the SOS pathway and horizontal gene transfer. We explore the molecular mechanisms involved in acquired resistance and discuss their viability as potential targets. We propose that additional studies into these adaptive mechanisms not only can provide insights into evolution but also can offer a strategy for potentiating our current antibiotic arsenal.

  14. Targets for Combating the Evolution of Acquired Antibiotic Resistance

    PubMed Central

    2015-01-01

    Bacteria possess a remarkable ability to rapidly adapt and evolve in response to antibiotics. Acquired antibiotic resistance can arise by multiple mechanisms but commonly involves altering the target site of the drug, enzymatically inactivating the drug, or preventing the drug from accessing its target. These mechanisms involve new genetic changes in the pathogen leading to heritable resistance. This recognition underscores the importance of understanding how such genetic changes can arise. Here, we review recent advances in our understanding of the processes that contribute to the evolution of antibiotic resistance, with a particular focus on hypermutation mediated by the SOS pathway and horizontal gene transfer. We explore the molecular mechanisms involved in acquired resistance and discuss their viability as potential targets. We propose that additional studies into these adaptive mechanisms not only can provide insights into evolution but also can offer a strategy for potentiating our current antibiotic arsenal. PMID:26016604

  15. Ganoderma lucidum Combined with the EGFR Tyrosine Kinase Inhibitor, Erlotinib Synergize to Reduce Inflammatory Breast Cancer Progression.

    PubMed

    Suárez-Arroyo, Ivette J; Rios-Fuller, Tiffany J; Feliz-Mosquea, Yismeilin R; Lacourt-Ventura, Mercedes; Leal-Alviarez, Daniel J; Maldonado-Martinez, Gerónimo; Cubano, Luis A; Martínez-Montemayor, Michelle M

    2016-01-01

    The high incidence of resistance to Tyrosine Kinase Inhibitors (TKIs) targeted against EGFR and downstream pathways has increased the necessity to identify agents that may be combined with these therapies to provide a sustained response for breast cancer patients. Here, we investigate the therapeutic potential of Ganoderma lucidum extract (GLE) in breast cancer, focusing on the regulation of the EGFR signaling cascade when treated with the EGFR TKI, Erlotinib. SUM-149, or intrinsic Erlotinib resistant MDA-MB-231 cells, and a successfully developed Erlotinib resistant cell line, rSUM-149 were treated with increasing concentrations of Erlotinib, GLE, or their combination (Erlotinib/GLE) for 72h. Treatment effects were tested on cell viability, cell proliferation, cell migration and invasion. To determine tumor progression, severe combined immunodeficient mice were injected with SUM-149 cells and then treated with Erlotinib/GLE or Erlotinib for 13 weeks. We assessed the protein expression of ERK1/2 and AKT in in vitro and in vivo models. Our results show that GLE synergizes with Erlotinib to sensitize SUM-149 cells to drug treatment, and overcomes intrinsic and developed Erlotinib resistance. Also, Erlotinib/GLE decreases SUM-149 cell viability, proliferation, migration and invasion. GLE increases Erlotinib sensitivity by inactivating AKT and ERK signaling pathways in our models. We conclude that a combinatorial therapeutic approach may be the best way to increase prognosis in breast cancer patients with EGFR overexpressing tumors. PMID:26958085

  16. Ganoderma lucidum Combined with the EGFR Tyrosine Kinase Inhibitor, Erlotinib Synergize to Reduce Inflammatory Breast Cancer Progression

    PubMed Central

    Suárez-Arroyo, Ivette J.; Rios-Fuller, Tiffany J.; Feliz-Mosquea, Yismeilin R.; Lacourt-Ventura, Mercedes; Leal-Alviarez, Daniel J.; Maldonado-Martinez, Gerónimo; Cubano, Luis A.; Martínez-Montemayor, Michelle M.

    2016-01-01

    The high incidence of resistance to Tyrosine Kinase Inhibitors (TKIs) targeted against EGFR and downstream pathways has increased the necessity to identify agents that may be combined with these therapies to provide a sustained response for breast cancer patients. Here, we investigate the therapeutic potential of Ganoderma lucidum extract (GLE) in breast cancer, focusing on the regulation of the EGFR signaling cascade when treated with the EGFR TKI, Erlotinib. SUM-149, or intrinsic Erlotinib resistant MDA-MB-231 cells, and a successfully developed Erlotinib resistant cell line, rSUM-149 were treated with increasing concentrations of Erlotinib, GLE, or their combination (Erlotinib/GLE) for 72h. Treatment effects were tested on cell viability, cell proliferation, cell migration and invasion. To determine tumor progression, severe combined immunodeficient mice were injected with SUM-149 cells and then treated with Erlotinib/GLE or Erlotinib for 13 weeks. We assessed the protein expression of ERK1/2 and AKT in in vitro and in vivo models. Our results show that GLE synergizes with Erlotinib to sensitize SUM-149 cells to drug treatment, and overcomes intrinsic and developed Erlotinib resistance. Also, Erlotinib/GLE decreases SUM-149 cell viability, proliferation, migration and invasion. GLE increases Erlotinib sensitivity by inactivating AKT and ERK signaling pathways in our models. We conclude that a combinatorial therapeutic approach may be the best way to increase prognosis in breast cancer patients with EGFR overexpressing tumors. PMID:26958085

  17. Ganoderma lucidum Combined with the EGFR Tyrosine Kinase Inhibitor, Erlotinib Synergize to Reduce Inflammatory Breast Cancer Progression.

    PubMed

    Suárez-Arroyo, Ivette J; Rios-Fuller, Tiffany J; Feliz-Mosquea, Yismeilin R; Lacourt-Ventura, Mercedes; Leal-Alviarez, Daniel J; Maldonado-Martinez, Gerónimo; Cubano, Luis A; Martínez-Montemayor, Michelle M

    2016-01-01

    The high incidence of resistance to Tyrosine Kinase Inhibitors (TKIs) targeted against EGFR and downstream pathways has increased the necessity to identify agents that may be combined with these therapies to provide a sustained response for breast cancer patients. Here, we investigate the therapeutic potential of Ganoderma lucidum extract (GLE) in breast cancer, focusing on the regulation of the EGFR signaling cascade when treated with the EGFR TKI, Erlotinib. SUM-149, or intrinsic Erlotinib resistant MDA-MB-231 cells, and a successfully developed Erlotinib resistant cell line, rSUM-149 were treated with increasing concentrations of Erlotinib, GLE, or their combination (Erlotinib/GLE) for 72h. Treatment effects were tested on cell viability, cell proliferation, cell migration and invasion. To determine tumor progression, severe combined immunodeficient mice were injected with SUM-149 cells and then treated with Erlotinib/GLE or Erlotinib for 13 weeks. We assessed the protein expression of ERK1/2 and AKT in in vitro and in vivo models. Our results show that GLE synergizes with Erlotinib to sensitize SUM-149 cells to drug treatment, and overcomes intrinsic and developed Erlotinib resistance. Also, Erlotinib/GLE decreases SUM-149 cell viability, proliferation, migration and invasion. GLE increases Erlotinib sensitivity by inactivating AKT and ERK signaling pathways in our models. We conclude that a combinatorial therapeutic approach may be the best way to increase prognosis in breast cancer patients with EGFR overexpressing tumors.

  18. Acquired resistance to gemcitabine and cross-resistance in human pancreatic cancer clones.

    PubMed

    Yoneyama, Hiroshi; Takizawa-Hashimoto, Asako; Takeuchi, Osamu; Watanabe, Yukiko; Atsuda, Koichiro; Asanuma, Fumiki; Yamada, Yoshinori; Suzuki, Yukio

    2015-01-01

    The efficacy of gemcitabine (GEM), a standard treatment agent for pancreatic cancer, is insufficient because of primary or acquired resistance to this drug. Patients with tumors intrinsically sensitive to GEM gradually acquire resistance and require a shift to second agents, which are associated with the risk of cross-resistance. However, whether cross-resistance is actually present has long been disputed. Using six GEM-resistant and four highly GEM-resistant clones derived from the pancreatic cancer cell line BxPC-3, we determined the resistance of each clone and parent cell line to GEM and four anticancer agents (5-FU, CDDP, CPT-11, and DTX). The GEM-resistant clones had different resistances to GEM and other agents, and did not develop a specific pattern of cross-resistance. This result shows that tumor cells are heterogeneous. However, all highly GEM-resistant clones presented overexpression of ribonucleotide reductase subunit M1 (RRM1), a target enzyme for metabolized GEM, and showed cross-resistance with 5-FU. The expression level of RRM1 was high; therefore, resistance to GEM was high. We showed that a tumor cell acquired resistance to GEM, and cross-resistance developed in one clone. These results suggest that only cells with certain mechanisms for high-level resistance to GEM survive against selective pressure applied by highly concentrated GEM. RRM1 may be one of the few factors that can induce high resistance to GEM and a suitable therapeutic target for GEM-resistant pancreatic cancer.

  19. Inducible and Acquired Clarithromycin Resistance in the Mycobacterium abscessus Complex

    PubMed Central

    Rubio, Marc; March, Francesca; Garrigó, Montserrat; Moreno, Carmen; Español, Montserrat; Coll, Pere

    2015-01-01

    Purpose Clarithromycin was considered the cornerstone for the treatment of Mycobacterium abscessus complex infections. Genetic resistance mechanisms have been described and many experts propose amikacin as an alternative. Nevertheless, clarithromycin has several advantages; therefore, it is necessary to identify the non-functional erm(41) allele to determine the most suitable treatment. The aims of this study were to characterize the molecular mechanisms of clarithromycin resistance in a collection of Mycobacterium abscessus complex isolates and to verify the relationship between these mechanisms and the antibiogram. Materials and Methods Clinical isolates of M. abscessus complex (n = 22) from 16 patients were identified using four housekeeping genes (rpoB, secA1, sodA and hsp65), and their genetic resistance was characterized by studying erm(41) and rrl genes. Nine strains were recovered from the clinical isolates and subjected to E-test and microdilution clarithromycin susceptibility tests, with readings at 3, 7 and 14 days. Results We classified 11/16 (68.8%) M. abscessus subsp. abscessus, 4/16 (25.0%) M. abscessus subsp. bolletii, and 1/16 (6.3%) M. abscessus subsp. massiliense. T28 erm(41) allele was observed in 8 Mycobacterium abscessus subps. abscessus and 3 Mycobacterium abscessus subsp. bolletii. One strain of M. abscessus subsp. bolletii had an erm(41) gene truncated and was susceptible to clarithromycin. No mutations were observed in rrl gene first isolates. In three patients, follow-up of initial rrl wild-type strains showed acquired resistance. Conclusions Most clinical isolates of M. abscessus complex had inducible resistance to clarithromycin and total absence of constitutive resistance. Our findings showed that the acquisition of resistance mutations in rrl gene was associated with functional and non-functional erm(41) gene. Caution is needed when using erm(41) sequencing alone to identify M. abscessus subspecies. This study reports an acquired

  20. Transcriptional plasticity promotes primary and acquired resistance to BET inhibition

    PubMed Central

    Neumann, Tobias; Muerdter, Felix; Roe, Jae-Seok; Muhar, Matthias; Deswal, Sumit; Cerny-Reiterer, Sabine; Peter, Barbara; Jude, Julian; Hoffmann, Thomas; Boryń, Łukasz M.; Axelsson, Elin; Schweifer, Norbert; Tontsch-Grunt, Ulrike; Dow, Lukas E.; Gianni, Davide; Pearson, Mark; Valent, Peter; Stark, Alexander; Kraut, Norbert; Vakoc, Christopher R.; Zuber, Johannes

    2016-01-01

    Summary Following the discovery of BRD4 as a non-oncogene addiction target in acute myeloid leukemia (AML)1,2, BET inhibitors are being explored as promising therapeutic avenue in numerous cancers3–5. While clinical trials have reported single-agent activity in advanced hematologic malignancies6, mechanisms determining the response to BET inhibition remain poorly understood. To identify factors involved in primary and acquired BET resistance in leukemia, we performed a chromatin-focused RNAi screen in a sensitive MLL/AF9; NrasG12D -driven AML model, and investigated dynamic transcriptional profiles in sensitive and resistant murine and human leukemias. Our screen reveals that suppression of the PRC2 complex, contrary to effects in other contexts, promotes BET inhibitor resistance in AML. PRC2 suppression does not directly affect the regulation of Brd4-dependent transcripts, but facilitates the remodeling of regulatory pathways that restore the transcription of key targets such as Myc. Similarly, while BET inhibition triggers acute MYC repression in human leukemias regardless of their sensitivity, resistant leukemias are uniformly characterized by their ability to rapidly restore MYC transcription. This process involves the activation and recruitment of WNT signaling components, which compensate for the loss of BRD4 and drive resistance in various cancer models. Dynamic ChIP- and STARR-seq enhancer profiles reveal that BET-resistant states are characterized by remodeled regulatory landscapes, involving the activation of a focal MYC enhancer that recruits WNT machinery in response to BET inhibition. Together, our results identify and validate WNT signaling as a driver and candidate biomarker of primary and acquired BET resistance in leukemia, and implicate the rewiring of transcriptional programs as an important mechanism promoting resistance to BET inhibitors and, potentially, other chromatin-targeted therapies. PMID:26367798

  1. Erlotinib Pretreatment Improves Photodynamic Therapy of Non-Small Cell Lung Carcinoma Xenografts via Multiple Mechanisms.

    PubMed

    Gallagher-Colombo, Shannon M; Miller, Joann; Cengel, Keith A; Putt, Mary E; Vinogradov, Sergei A; Busch, Theresa M

    2015-08-01

    Aberrant expression of the epidermal growth factor receptor (EGFR) is a common characteristic of many cancers, including non-small cell lung carcinoma (NSCLC), head and neck squamous cell carcinoma, and ovarian cancer. Although EGFR is currently a favorite molecular target for the treatment of these cancers, inhibition of the receptor with small-molecule inhibitors (i.e., erlotinib) or monoclonal antibodies (i.e., cetuximab) does not provide long-term therapeutic benefit as standalone treatment. Interestingly, we have found that addition of erlotinib to photodynamic therapy (PDT) can improve treatment response in typically erlotinib-resistant NSCLC tumor xenografts. Ninety-day complete response rates of 63% are achieved when erlotinib is administered in three doses before PDT of H460 human tumor xenografts, compared with 16% after PDT-alone. Similar benefit is found when erlotinib is added to PDT of A549 NCSLC xenografts. Improved response is accompanied by increased vascular shutdown, and erlotinib increases the in vitro cytotoxicity of PDT to endothelial cells. Tumor uptake of the photosensitizer (benzoporphyrin derivative monoacid ring A; BPD) is increased by the in vivo administration of erlotinib; nevertheless, this elevation of BPD levels only partially accounts for the benefit of erlotinib to PDT. Thus, pretreatment with erlotinib augments multiple mechanisms of PDT effect that collectively lead to large improvements in therapeutic efficacy. These data demonstrate that short-duration administration of erlotinib before PDT can greatly improve the responsiveness of even erlotinib-resistant tumors to treatment. Results will inform clinical investigation of EGFR-targeting therapeutics in conjunction with PDT.

  2. Combined Vascular Endothelial Growth Factor Receptor and Epidermal Growth Factor Receptor (EGFR) Blockade Inhibits Tumor Growth in Xenograft Models of EGFR Inhibitor Resistance

    PubMed Central

    Naumov, George N.; Nilsson, Monique B.; Cascone, Tina; Briggs, Alexandra; Straume, Oddbjorn; Akslen, Lars A.; Lifshits, Eugene; Byers, Lauren Averett; Xu, Li; Wu, Hua-kang; Jänne, Pasi; Kobayashi, Susumu; Halmos, Balazs; Tenen, Daniel; Tang, Xi M.; Engelman, Jeffrey; Yeap, Beow; Folkman, Judah; Johnson, Bruce E.; Heymach, John V.

    2010-01-01

    Purpose The epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKI) gefitinib and erlotinib benefit some non–small cell lung cancer (NSCLC) patients, but most do not respond (primary resistance) and those who initially respond eventually progress (acquired resistance). EGFR TKI resistance is not completely understood and has been associated with certain EGFR and K-RAS mutations and MET amplification. Experimental Design We hypothesized that dual inhibition of the vascular endothelial growth factor (VEGF) and EGFR pathways may overcome primary and acquired resistance. We investigated the VEGF receptor/EGFR TKI vandetanib, and the combination of bevacizumab and erlotinib in vivo using xenograft models of EGFR TKI sensitivity, primary resistance, and three models of acquired resistance, including models with mutated K-RAS and secondary EGFR T790M mutation. Results Vandetanib, gefitinib, and erlotinib had similar profiles of in vitro activity and caused sustained tumor regressions in vivo in the sensitive HCC827 model. In all four resistant models, vandetanib and bevacizumab/erlotinib were significantly more effective than erlotinib or gefitinib alone. Erlotinib resistance was associated with a rise in both host and tumor-derived VEGF but not EGFR secondary mutations in the KRAS mutant-bearing A549 xenografts. Dual inhibition reduced tumor endothelial proliferation compared with VEGF or EGFR blockade alone, suggesting that the enhanced activity of dual inhibition is due at least in part to antiendothelial effects. Conclusion These studies suggest that erlotinib resistance may be associated with a rise in both tumor cell and host stromal VEGF and that combined blockade of the VEGFR and EGFR pathways can abrogate primary or acquired resistance to EGFR TKIs. This approach merits further evaluation in NSCLC patients. PMID:19447865

  3. Recent advances in systemic acquired resistance research--a review.

    PubMed

    Hunt, M D; Neuenschwander, U H; Delaney, T P; Weymann, K B; Friedrich, L B; Lawton, K A; Steiner, H Y; Ryals, J A

    1996-11-01

    Little is known about the signal transduction events that lead to the establishment of the broad-spectrum, inducible plant immunity called systemic acquired resistance (SAR). Salicylic acid (SA) accumulation has been shown to be essential for the expression of SAR and plays a key role in SAR signaling. Hydrogen peroxide has been proposed to serve as a second messenger of SA. However, our results do not support such a role in the establishment of SAR. Further elucidation of SAR signal transduction has been facilitated by the identification and characterization of mutants. The lesions simulating disease (lsd). resistance response mutant class exhibits spontaneous lesions similar to those that occur during the hypersensitive response. Interestingly, some lsd mutants lose their lesioned phenotype when SA accumulation is prevented by expression of the nahG gene (encoding salicylate hydroxylase), thereby providing evidence for a feedback loop in SAR signal transduction. Characterization of a mutant non-responsive to SAR activator treatments has provided additional evidence for common signaling components between SAR and gene-for-gene resistance.

  4. Community-Acquired Methicillin-Resistant Pyogenic Liver Abscess

    PubMed Central

    Cherian, Joel; Singh, Rahul; Varma, Muralidhar; Vidyasagar, Sudha; Mukhopadhyay, Chiranjay

    2016-01-01

    Pyogenic liver abscesses are rare with an incidence of 0.5% to 0.8% and are mostly due to hepatobiliary causes (40% to 60%). Most are polymicrobial with less than 10% being caused by Staphylococcus aureus. Of these, few are caused by methicillin-resistant Staphylococcus aureus (MRSA) and fewer still by a community-acquired strain. Here we present a case study of a patient with a community-acquired MRSA liver abscess. The patient presented with fever since 1 month and tender hepatomegaly. Blood tests revealed elevated levels of alkaline phosphatase, C-reactive protein, erythrocyte sedimentation rate, and neutrophilic leukocytosis. Blood cultures were sterile. Ultrasound of the abdomen showed multiple abscesses, from which pus was drained and MRSA isolated. Computed tomography of the abdomen did not show any source of infection, and an amebic serology was negative. The patient was started on vancomycin for 2 weeks, following which he became afebrile and was discharged on oral linezolid for 4 more weeks. Normally a liver abscess is treated empirically with ceftriaxone for pyogenic liver abscess and metronidazole for amebic liver abscess. However, if the patient has risk factors for a Staphylococcal infection, it is imperative that antibiotics covering gram-positive organisms be added while waiting for culture reports. PMID:27540556

  5. Cellular Memory of Acquired Stress Resistance in Saccharomyces cerevisiae

    PubMed Central

    Guan, Qiaoning; Haroon, Suraiya; Bravo, Diego González; Will, Jessica L.; Gasch, Audrey P.

    2012-01-01

    Cellular memory of past experiences has been observed in several organisms and across a variety of experiences, including bacteria “remembering” prior nutritional status and amoeba “learning” to anticipate future environmental conditions. Here, we show that Saccharomyces cerevisiae maintains a multifaceted memory of prior stress exposure. We previously demonstrated that yeast cells exposed to a mild dose of salt acquire subsequent tolerance to severe doses of H2O2. We set out to characterize the retention of acquired tolerance and in the process uncovered two distinct aspects of cellular memory. First, we found that H2O2 resistance persisted for four to five generations after cells were removed from the prior salt treatment and was transmitted to daughter cells that never directly experienced the pretreatment. Maintenance of this memory did not require nascent protein synthesis after the initial salt pretreatment, but rather required long-lived cytosolic catalase Ctt1p that was synthesized during salt exposure and then distributed to daughter cells during subsequent cell divisions. In addition to and separable from the memory of H2O2 resistance, these cells also displayed a faster gene-expression response to subsequent stress at >1000 genes, representing transcriptional memory. The faster gene-expression response requires the nuclear pore component Nup42p and serves an important function by facilitating faster reacquisition of H2O2 tolerance after a second cycle of salt exposure. Memory of prior stress exposure likely provides a significant advantage to microbial populations living in ever-changing environments. PMID:22851651

  6. Cellular memory of acquired stress resistance in Saccharomyces cerevisiae.

    PubMed

    Guan, Qiaoning; Haroon, Suraiya; Bravo, Diego González; Will, Jessica L; Gasch, Audrey P

    2012-10-01

    Cellular memory of past experiences has been observed in several organisms and across a variety of experiences, including bacteria "remembering" prior nutritional status and amoeba "learning" to anticipate future environmental conditions. Here, we show that Saccharomyces cerevisiae maintains a multifaceted memory of prior stress exposure. We previously demonstrated that yeast cells exposed to a mild dose of salt acquire subsequent tolerance to severe doses of H(2)O(2). We set out to characterize the retention of acquired tolerance and in the process uncovered two distinct aspects of cellular memory. First, we found that H(2)O(2) resistance persisted for four to five generations after cells were removed from the prior salt treatment and was transmitted to daughter cells that never directly experienced the pretreatment. Maintenance of this memory did not require nascent protein synthesis after the initial salt pretreatment, but rather required long-lived cytosolic catalase Ctt1p that was synthesized during salt exposure and then distributed to daughter cells during subsequent cell divisions. In addition to and separable from the memory of H(2)O(2) resistance, these cells also displayed a faster gene-expression response to subsequent stress at >1000 genes, representing transcriptional memory. The faster gene-expression response requires the nuclear pore component Nup42p and serves an important function by facilitating faster reacquisition of H(2)O(2) tolerance after a second cycle of salt exposure. Memory of prior stress exposure likely provides a significant advantage to microbial populations living in ever-changing environments. PMID:22851651

  7. Silencing kinase-interacting stathmin gene enhances erlotinib sensitivity by inhibiting Ser¹⁰ p27 phosphorylation in epidermal growth factor receptor-expressing breast cancer.

    PubMed

    Zhang, Dongwei; Tari, Ana M; Akar, Ugur; Arun, Banu K; LaFortune, Tiffany A; Nieves-Alicea, Rene; Hortobagyi, Gabriel N; Ueno, Naoto T

    2010-11-01

    The epidermal growth factor receptor (EGFR) signaling pathway has emerged as a promising target for cancer therapy. EGFR tyrosine kinase inhibitors (TKI) such as erlotinib have been approved for cancer treatment but have shown very limited activity in breast cancer patients. Clarifying the molecular mechanism underlying resistance to EGFR TKIs could lead to more effective treatment against breast cancer. We previously reported that the sensitivity of breast cancer cells to erlotinib is partially dependent on p27 and that cytoplasmic localization of p27 is associated with erlotinib resistance. In the present study, we found that erlotinib induces p27 phosphorylation at Ser¹⁰ (S10), and S10 p27 phosphorylation leads to erlotinib resistance in EGFR-expressing breast cancer. Inhibiting S10 phosphorylation of p27 by knocking down human kinase-interacting stathmin (KIS), a nuclear protein that can phosphorylate p27 at S10, led to p27 accumulation in the nucleus and enhanced erlotinib-mediated cytotoxicity. Further, in vivo KIS gene silencing enhanced the antitumor activity of erlotinib in an orthotopic breast cancer xenograft model. KIS depletion also enhanced erlotinib sensitivity in erlotinib-resistant EGFR-expressing triple-negative breast cancer cells. Our study provides a rationale for the development of combinations of erlotinib with KIS inhibition to overcome EGFR TKI resistance in EGFR-expressing breast cancer.

  8. Genomic Correlate of Exceptional Erlotinib Response in Head and Neck Squamous Cell Carcinoma

    PubMed Central

    Van Allen, Eliezer M.; Lui, Vivian W. Y.; Egloff, Ann Marie; Goetz, Eva M.; Li, Hua; Johnson, Jonas T.; Duvvuri, Umamaheswar; Bauman, Julie E.; Stransky, Nicolas; Zeng, Yan; Gilbert, Breean R.; Pendleton, Kelsey P.; Wang, Lin; Chiosea, Simion; Sougnez, Carrie; Wagle, Nikhil; Zhang, Fan; Du, Yu; Close, David; Johnston, Paul A.; McKenna, Aaron; Carter, Scott L.; Golub, Todd R.; Getz, Gad; Mills, Gordon B.; Garraway, Levi A.; Grandis, Jennifer R.

    2015-01-01

    IMPORTANCE Randomized clinical trials demonstrate no benefit for epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors in unselected patients with head and neck squamous cell carcinoma (HNSCC). However, a patient with stage IVA HNSCC received 13 days of neoadjuvant erlotinib and experienced a near-complete histologic response. OBJECTIVE To determine a mechanism of exceptional response to erlotinib therapy in HNSCC. DESIGN, SETTING, AND PARTICIPANTS Single patient with locally advanced HNSCC who received erlotinib monotherapy in a window-of-opportunity clinical trial (patients scheduled to undergo primary cancer surgery are treated briefly with an investigational agent). Whole-exome sequencing of pretreatment tumor and germline patient samples was performed at a quaternary care academic medical center, and a candidate somatic variant was experimentally investigated for mediating erlotinib response. INTERVENTION A brief course of erlotinib monotherapy followed by surgical resection. MAIN OUTCOMES AND MEASURES Identification of pretreatment tumor somatic alterations that may contribute to the exceptional response to erlotinib. Hypotheses were formulated regarding enhanced erlotinib response in preclinical models harboring the patient tumor somatic variant MAPK1 E322K following the identification of tumor somatic variants. RESULTS No EGFR alterations were observed in the pretreatment tumor DNA. Paradoxically, the tumor harbored an activating MAPK1 E322K mutation (allelic fraction 0.13), which predicts ERK activation and erlotinib resistance in EGFR-mutant lung cancer. The HNSCC cells with MAPK1 E322K exhibited enhanced EGFR phosphorylation and erlotinib sensitivity compared with wild-type MAPK1 cells. CONCLUSIONS AND RELEVANCE Selective erlotinib use in HNSCC may be informed by precision oncology approaches. PMID:26181029

  9. Erlotinib-related bilateral anterior uveitis

    PubMed Central

    Ali, Kashif; Kumar, Indu; Usman-Saeed, Muniba; Usman Saeed, Muhammad

    2011-01-01

    The authors report the case of a 68-year-old woman with secondary adenocarcinoma of the lungs from an unknown primary. Erlotinib was started which produced symptoms suggestive of uveitis. Erlotinib was stopped and restarted a month later at a lower dose, which resulted in severe bilateral anterior uveitis. The uveitis settled after stopping erlotinib and treatment with topical steroids and cycloplegics. To the best of the authors’ knowledge, this is the first case of erlotinib-related anterior uveitis. PMID:22694887

  10. Erlotinib Versus Radiation Therapy for Brain Metastases in Patients With EGFR-Mutant Lung Adenocarcinoma

    SciTech Connect

    Gerber, Naamit K.; Yamada, Yoshiya; Rimner, Andreas; Shi, Weiji; Riely, Gregory J.; Beal, Kathryn; Yu, Helena A.; Chan, Timothy A.; Zhang, Zhigang; Wu, Abraham J.

    2014-06-01

    Purpose/Objectives: Radiation therapy (RT) is the principal modality in the treatment of patients with brain metastases (BM). However, given the activity of EGFR tyrosine kinase inhibitors in the central nervous system, it is uncertain whether upfront brain RT is necessary for patients with EGFR-mutant lung adenocarcinoma with BM. Methods and Materials: Patients with EGFR-mutant lung adenocarcinoma and newly diagnosed BM were identified. Results: 222 patients were identified. Exclusion criteria included prior erlotinib use, presence of a de novo erlotinib resistance mutation, or incomplete data. Of the remaining 110 patients, 63 were treated with erlotinib, 32 with whole brain RT (WBRT), and 15 with stereotactic radiosurgery (SRS). The median overall survival (OS) for the whole cohort was 33 months. There was no significant difference in OS between the WBRT and erlotinib groups (median, 35 vs 26 months; P=.62), whereas patients treated with SRS had a longer OS than did those in the erlotinib group (median, 64 months; P=.004). The median time to intracranial progression was 17 months. There was a longer time to intracranial progression in patients who received WBRT than in those who received erlotinib upfront (median, 24 vs 16 months, P=.04). Patients in the erlotinib or SRS group were more likely to experience intracranial failure as a component of first failure, whereas WBRT patients were more likely to experience failure outside the brain (P=.004). Conclusions: The survival of patients with EGFR-mutant adenocarcinoma with BM is notably long, whether they receive upfront erlotinib or brain RT. We observed longer intracranial control with WBRT, even though the WBRT patients had a higher burden of intracranial disease. Despite the equivalent survival between the WBRT and erlotinib group, this study underscores the role of WBRT in producing durable intracranial control in comparison with a targeted biologic agent with known central nervous system activity.

  11. Socioeconomic and behavioral factors leading to acquired bacterial resistance to antibiotics in developing countries.

    PubMed Central

    Okeke, I. N.; Lamikanra, A.; Edelman, R.

    1999-01-01

    In developing countries, acquired bacterial resistance to antimicrobial agents is common in isolates from healthy persons and from persons with community-acquired infections. Complex socioeconomic and behavioral factors associated with antibiotic resistance, particularly regarding diarrheal and respiratory pathogens, in developing tropical countries, include misuse of antibiotics by health professionals, unskilled practitioners, and laypersons; poor drug quality; unhygienic conditions accounting for spread of resistant bacteria; and inadequate surveillance. PMID:10081668

  12. Community-acquired Methicillin-resistant Staphylococcus aureus, Uruguay

    PubMed Central

    Ma, Xiao Xue; Galiana, Antonio; Pedreira, Walter; Mowszowicz, Martin; Christophersen, Inés; Machiavello, Silvia; Lope, Liliana; Benaderet, Sara; Buela, Fernanda; Vicentino, Walter; Albini, María; Bertaux, Olivier; Constenla, Irene; Bagnulo, Homero; Llosa, Luis; Ito, Teruyo

    2005-01-01

    A novel, methicillin-resistant Staphylococcus aureus clone (Uruguay clone) with a non–multidrug-resistant phenotype caused a large outbreak, including 7 deaths, in Montevideo, Uruguay. The clone was distinct from the highly virulent community clone represented by strain MW2, although both clones carried Panton-Valentine leukocidin gene and cna gene. PMID:15963301

  13. [A case of non-acquired immunodeficiency syndrome-defining lung adenocarcinoma in a multidrug-resistant human immunodeficiency virus-positive patient].

    PubMed

    Mori, Naoyoshi; Maeda, Hikaru; Fujiwara, Kentarou; Taniguchi, Haruki

    2013-10-01

    We report a case of non-acquired immunodeficiency syndrome-defining lung adenocarcinoma in a multidrug-resistant human immunodeficiency virus (HIV)-positive patient. The patient was a 47-year-old Japanese woman who received salvage combination anti-retroviral therapy with darunavir plus ritonavir plus raltegravir plus tenofovir/emtricitabine in May 2009. She was diagnosed with lung adenocarcinoma (T3N3M1, stage IV) in November 2010 and was not found to possess any activating mutations in the epidermal growth factor receptor gene. Therefore, 6 courses of carboplatin plus pemetrexed and 3 courses of gemcitabine followed by erlotinib were administrated, and therapy was changed to home medical care. The only drug-related adverse event was grade 1 neutropenia, and drug interaction between the simultaneously administered anti-retroviral and chemotherapeutic agents was not confirmed. The patient battled lung adenocarcinoma for 1 year after the diagnosis and died of cancer progression in October 2011. Her performance status was stable and the CD4 (+) lymphocyte count and HIV load were well controlled throughout the course of treatment. In conclusion, the agents used for this patient show high tolerability and can be used as an effective treatment strategy for lung cancer occurring in HIV-positive patients.

  14. Systemic acquired resistance delays race shifts to major resistance genes in bell pepper.

    PubMed

    Romero, A M; Ritchie, D F

    2004-12-01

    ABSTRACT The lack of durability of host plant disease resistance is a major problem in disease control. Genotype-specific resistance that involves major resistance (R) genes is especially prone to failure. The compatible (i.e., disease) host-pathogen interaction with systemic acquired resistance (SAR) has been studied extensively, but the incompatible (i.e., resistant) interaction less so. Using the pepper-bacterial spot (causal agent, Xanthomonas axonopodis pv. vesicatoria) pathosystem, we examined the effect of SAR in reducing the occurrence of race-change mutants that defeat R genes in laboratory, greenhouse, and field experiments. Pepper plants carrying one or more R genes were sprayed with the plant defense activator acibenzolar-S-methyl (ASM) and challenged with incompatible strains of the pathogen. In the greenhouse, disease lesions first were observed 3 weeks after inoculation. ASM-treated plants carrying a major R gene had significantly fewer lesions caused by both the incompatible (i.e., hypersensitive) and compatible (i.e., disease) responses than occurred on nonsprayed plants. Bacteria isolated from the disease lesions were confirmed to be race-change mutants. In field experiments, there was a delay in the detection of race-change mutants and a reduction in disease severity. Decreased disease severity was associated with a reduction in the number of race-change mutants and the suppression of disease caused by the race-change mutants. This suggests a possible mechanism related to a decrease in the pathogen population size, which subsequently reduces the number of race-change mutants for the selection pressure of R genes. Thus, inducers of SAR are potentially useful for increasing the durability of genotype-specific resistance conferred by major R genes.

  15. Overcoming acquired resistance to kinase inhibition: the cases of EGFR, ALK and BRAF.

    PubMed

    Giroux, Simon

    2013-01-15

    In the past decade, several kinase inhibitors have been approved based on their clinical benefit for cancer patients. Unfortunately, in many cases, patients develop resistance to these agents via secondary mutations and alternative mechanisms. This review will focus on the cases of acquired resistance to EGFR and ALK inhibitors for non-small cell lung cancer patients and BRAF inhibitors for melanoma patients. I will overview the main causes of acquired resistance, and explore the chemical scaffolds as well as combination of drugs, used to tackle these major causes of resistance. PMID:23245516

  16. Community-acquired methicillin-resistant Staphylococcus aureus: community transmission, pathogenesis, and drug resistance.

    PubMed

    Yamamoto, Tatsuo; Nishiyama, Akihito; Takano, Tomomi; Yabe, Shizuka; Higuchi, Wataru; Razvina, Olga; Shi, Da

    2010-08-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is able to persist not only in hospitals (with a high level of antimicrobial agent use) but also in the community (with a low level of antimicrobial agent use). The former is called hospital-acquired MRSA (HA-MRSA) and the latter community-acquired MRSA (CA-MRSA). It is believed MRSA clones are generated from S. aureus through insertion of the staphylococcal cassette chromosome mec (SCCmec), and outbreaks occur as they spread. Several worldwide and regional clones have been identified, and their epidemiological, clinical, and genetic characteristics have been described. CA-MRSA is likely able to survive in the community because of suitable SCCmec types (type IV or V), a clone-specific colonization/infection nature, toxin profiles (including Pantone-Valentine leucocidin, PVL), and narrow drug resistance patterns. CA-MRSA infections are generally seen in healthy children or young athletes, with unexpected cases of diseases, and also in elderly inpatients, occasionally surprising clinicians used to HA-MRSA infections. CA-MRSA spreads within families and close-contact groups or even through public transport, demonstrating transmission cores. Re-infection (including multifocal infection) frequently occurs, if the cores are not sought out and properly eradicated. Recently, attention has been given to CA-MRSA (USA300), which originated in the US, and is growing as HA-MRSA and also as a worldwide clone. CA-MRSA infection in influenza season has increasingly been noted as well. MRSA is also found in farm and companion animals, and has occasionally transferred to humans. As such, the epidemiological, clinical, and genetic behavior of CA-MRSA, a growing threat, is focused on in this study. PMID:20336341

  17. Follow-up of erlotinib related uveitis

    PubMed Central

    Kumar, Indu; Ali, Kashif; Usman-Saeed, Muniba; Saeed, Muhammad Usman

    2012-01-01

    The authors report the follow-up of a 68-year-old lady with bilateral anterior uveitis secondary to erlotinib. Erlotinib was started and stopped after symptoms and signs suggestive of severe bilateral anterior uveitis were noted. The patient developed signs of a non-ST elevation myocardial infarction, 12 days after stopping the erlotinib, and recovered without major problems. The patient also reported intermittent low-grade fever since starting erlotinib which resolved after stopping this drug. No further symptoms of uveitis were noted up to 6 month follow-up. The patient reported improved well being, resolution of ocular symptoms and intermittent low-grade fever at last follow-up (6 months after stopping erlotinib). PMID:22892235

  18. Community-Acquired Methicillin-Resistant "Staphylococcus aureus": Considerations for School Nurses

    ERIC Educational Resources Information Center

    Alex, Aniltta; Letizia, MariJo

    2007-01-01

    Methicillin-resistant "Staphylococcus aureus" (MRSA) is a disease-causing organism that has been present in hospital settings since the 1960s. However, a genetically distinct strain of MRSA, called community-acquired methicillin-resistant "Staphylococcus aureus" (CA-MRSA), has emerged in recent years in community settings among healthy…

  19. Overexpression of Specific CD44 Isoforms Is Associated with Aggressive Cell Features in Acquired Endocrine Resistance

    PubMed Central

    Bellerby, Rebecca; Smith, Chris; Kyme, Sue; Gee, Julia; Günthert, Ursula; Green, Andy; Rakha, Emad; Barrett-Lee, Peter; Hiscox, Stephen

    2016-01-01

    While endocrine therapy is the mainstay of ER+ breast cancer, the clinical effectiveness of these agents is limited by the phenomenon of acquired resistance that is associated with disease relapse and poor prognosis. Our previous studies revealed that acquired resistance is accompanied by a gain in cellular invasion and migration and also that CD44 family proteins are overexpressed in the resistant phenotype. Given the association of CD44 with tumor progression, we hypothesized that its overexpression may act to promote the aggressive behavior of endocrine-resistant breast cancers. Here, we have investigated further the role of two specific CD44 isoforms, CD44v3 and CD44v6, in the endocrine-resistant phenotype. Our data revealed that overexpression of CD44v6, but not CD44v3, in endocrine-sensitive MCF-7 cells resulted in a gain in EGFR signaling, enhanced their endogenous invasive capacity, and attenuated their response to endocrine treatment. Suppression of CD44v6 in endocrine-resistant cell models was associated with a reduction in their invasive capacity. Our data suggest that upregulation of CD44v6 in acquired resistant breast cancer may contribute to a gain in the aggressive phenotype of these cells and loss of endocrine response through transactivation of the EGFR pathway. Future therapeutic targeting of CD44v6 may prove to be an effective strategy alongside EGFR-targeted agents in delaying/preventing acquired resistance in breast cancer. PMID:27379207

  20. The kinetics and quality of acquired resistance in self-healing and metastatic leishmaniasis.

    PubMed Central

    Poulter, L W

    1979-01-01

    Quantitative methods for enumerating viable L. enriettii in tissues have been used to determine the course of cutaneous leishmaniasis in guinea-pigs. The development and kinetics of acquired resistance have been evaluated in self-healing and chronic metastatic forms of the disease. It is revealed that 3 weeks after a primary local infection, a standard challenge infection is totally eliminated within 7 days. This resistance is as strong in animals with a current infection as it is in those that have fully recovered from such an infection. Animals developing metastatic disease also develop resistance to the standard challenge. This is initially as strong as in animals with only localized disease, but wanes with the progression of the infection. Although the quality of resistance becomes poorer in animals with metastatic infection, it is not lost completely. The relationship between acquired resistance and the resolution of the primary infection is discussed. PMID:380855

  1. Non-genomic and Immune Evolution of Melanoma Acquiring MAPKi Resistance.

    PubMed

    Hugo, Willy; Shi, Hubing; Sun, Lu; Piva, Marco; Song, Chunying; Kong, Xiangju; Moriceau, Gatien; Hong, Aayoung; Dahlman, Kimberly B; Johnson, Douglas B; Sosman, Jeffrey A; Ribas, Antoni; Lo, Roger S

    2015-09-10

    Clinically acquired resistance to MAPK inhibitor (MAPKi) therapies for melanoma cannot be fully explained by genomic mechanisms and may be accompanied by co-evolution of intra-tumoral immunity. We sought to discover non-genomic mechanisms of acquired resistance and dynamic immune compositions by a comparative, transcriptomic-methylomic analysis of patient-matched melanoma tumors biopsied before therapy and during disease progression. Transcriptomic alterations across resistant tumors were highly recurrent, in contrast to mutations, and were frequently correlated with differential methylation of tumor cell-intrinsic CpG sites. We identified in the tumor cell compartment supra-physiologic c-MET up-expression, infra-physiologic LEF1 down-expression and YAP1 signature enrichment as drivers of acquired resistance. Importantly, high intra-tumoral cytolytic T cell inflammation prior to MAPKi therapy preceded CD8 T cell deficiency/exhaustion and loss of antigen presentation in half of disease-progressive melanomas, suggesting cross-resistance to salvage anti-PD-1/PD-L1 immunotherapy. Thus, melanoma acquires MAPKi resistance with highly dynamic and recurrent non-genomic alterations and co-evolving intra-tumoral immunity.

  2. Non-genomic and Immune Evolution of Melanoma Acquiring MAPKi Resistance

    PubMed Central

    Hugo, Willy; Shi, Hubing; Sun, Lu; Piva, Marco; Song, ChunYing; Kong, Xiangju; Moriceau, Gatien; Hong, Aayoung; Dahlman, Kimberly B.; Johnson, Douglas B.; Sosman, Jeffrey A.; Ribas, Antoni; Lo, Roger S.

    2015-01-01

    SUMMARY Clinically acquired resistance to MAPK inhibitor (MAPKi) therapies for melanoma cannot be fully explained by genomic mechanisms and may be accompanied by co-evolution of intra-tumoral immunity. We sought to discover non-genomic mechanisms of acquired resistance and dynamic immune compositions by a comparative, transcriptomic-methylomic analysis of patient-matched melanoma tumors biopsied before therapy and during disease progression. Transcriptomic alterations across resistant tumors were highly recurrent, in contrast to mutations, and were frequently correlated with differential methylation of tumor cell-intrinsic CpG sites. We identified in the tumor cell compartment supra-physiologic c-MET up-expression, infra-physiologic LEF1 down-expression, and YAP1 signature enrichment as drivers of acquired resistance. Importantly, high intra-tumoral cytolytic T-cell inflammation prior to MAPKi therapy preceded CD8 T-cell deficiency/exhaustion and loss of antigen-presentation in half of disease-progressive melanomas, suggesting cross-resistance to salvage anti-PD-1/PD-L1 immunotherapy. Thus, melanoma acquires MAPKi-resistance with highly dynamic and recurrent non-genomic alterations and co-evolving intra-tumoral immunity. PMID:26359985

  3. Imaging the urokinase plasminongen activator receptor in preclinical breast cancer models of acquired drug resistance.

    PubMed

    LeBeau, Aaron M; Sevillano, Natalia; King, Mandy L; Duriseti, Sai; Murphy, Stephanie T; Craik, Charles S; Murphy, Laura L; VanBrocklin, Henry F

    2014-01-01

    Subtype-targeted therapies can have a dramatic impact on improving the quality and quantity of life for women suffering from breast cancer. Despite an initial therapeutic response, cancer recurrence and acquired drug-resistance are commonplace. Non-invasive imaging probes that identify drug-resistant lesions are urgently needed to aid in the development of novel drugs and the effective utilization of established therapies for breast cancer. The protease receptor urokinase plasminogen activator receptor (uPAR) is a target that can be exploited for non-invasive imaging. The expression of uPAR has been associated with phenotypically aggressive breast cancer and acquired drug-resistance. Acquired drug-resistance was modeled in cell lines from two different breast cancer subtypes, the uPAR negative luminal A subtype and the uPAR positive triple negative subtype cell line MDA-MB-231. MCF-7 cells, cultured to be resistant to tamoxifen (MCF-7 TamR), were found to significantly over-express uPAR compared to the parental cell line. uPAR expression was maintained when resistance was modeled in triple-negative breast cancer by generating doxorubicin and paclitaxel resistant MDA-MB-231 cells (MDA-MB-231 DoxR and MDA-MB-231 TaxR). Using the antagonistic uPAR antibody 2G10, uPAR was imaged in vivo by near-infrared (NIR) optical imaging and (111)In-single photon emission computed tomography (SPECT). Tumor uptake of the (111)In-SPECT probe was high in the three drug-resistant xenografts (> 46 %ID/g) and minimal in uPAR negative xenografts at 72 hours post-injection. This preclinical study demonstrates that uPAR can be targeted for imaging breast cancer models of acquired resistance leading to potential clinical applications. PMID:24505235

  4. Acquired antibiotic resistance among wild animals: the case of Iberian Lynx (Lynx pardinus).

    PubMed

    Sousa, Margarida; Gonçalves, Alexandre; Silva, Nuno; Serra, Rodrigo; Alcaide, Eva; Zorrilla, Irene; Torres, Carmen; Caniça, Manuela; Igrejas, Gilberto; Poeta, Patrícia

    2014-01-01

    The selective pressure generated by the clinical misuse of antibiotics has been the major driving force leading to the emergence of antibiotic resistance among bacteria. Antibiotics or even resistant bacteria are released into the environment and contaminate the surrounding areas. Human and animal populations in contact with these sources are able to become reservoirs of these resistant organisms. Then, due to the convergence between habitats, the contact of wild animals with other animals, humans, or human sources is now more common and this leads to an increase in the exchange of resistance determinants between their microbiota. Indeed, it seems that wildlife populations living in closer proximity to humans have higher levels of antibiotic resistance. Now, the Iberian Lynx (Lynx pardinus) is a part of this issue, being suggested as natural reservoir of acquired resistant bacteria. The emerging public health concern regarding microbial resistance to antibiotics is becoming true: the bacteria are evolving and are now affecting unintentional hosts.

  5. Overcoming EMT-associated resistance to anti-cancer drugs via Src/FAK pathway inhibition.

    PubMed

    Wilson, Catherine; Nicholes, Katrina; Bustos, Daisy; Lin, Eva; Song, Qinghua; Stephan, Jean-Philippe; Kirkpatrick, Donald S; Settleman, Jeff

    2014-09-15

    Epithelial to mesenchymal transition (EMT) is a key process in embryonic development and has been associated with cancer metastasis and drug resistance. For example, in EGFR mutated non-small cell lung cancers (NSCLC), EMT has been associated with acquired resistance to the EGFR inhibitor erlotinib. Moreover, "EGFR-addicted" cancer cell lines induced to undergo EMT become erlotinib-resistant in vitro. To identify potential therapeutic vulnerabilities specifically within these mesenchymal, erlotinib-resistant cells, we performed a small molecule screen of ~200 established anti-cancer agents using the EGFR mutant NSCLC HCC827 cell line and a corresponding mesenchymal derivative line. The mesenchymal cells were more resistant to most tested agents; however, a small number of agents showed selective growth inhibitory activity against the mesenchymal cells, with the most potent being the Abl/Src inhibitor, dasatinib. Analysis of the tyrosine phospho-proteome revealed several Src/FAK pathway kinases that were differentially phosphorylated in the mesenchymal cells, and RNAi depletion of the core Src/FAK pathway components in these mesenchymal cells caused apoptosis. These findings reveal a novel role for Src/FAK pathway kinases in drug resistance and identify dasatinib as a potential therapeutic for treatment of erlotinib resistance associated with EMT. PMID:25193862

  6. First report of infection with community-acquired methicillin-resistant Staphylococcus aureus in South America.

    PubMed

    Ribeiro, Apoena; Dias, Cícero; Silva-Carvalho, Maria Cícera; Berquó, Laura; Ferreira, Fabienne Antunes; Santos, Raquel Neves Soares; Ferreira-Carvalho, Bernadete Teixeira; Figueiredo, Agnes Marie

    2005-04-01

    Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) has recently emerged in the southwestern Pacific, North America, and Europe. These S. aureus isolates frequently shared some genetic characteristics, including the SCCmec type IV and lukS-lukF genes. In this paper we show that typical CA-MRSA isolates have spread to South America (Brazil).

  7. Acquired antimicrobial resistance in the intestinal microbiota of diverse cat populations.

    PubMed

    Moyaert, H; De Graef, E M; Haesebrouck, F; Decostere, A

    2006-08-01

    The aim of this study was to investigate the prevalence of acquired antimicrobial resistance in the resident intestinal microbiota of cats and to identify significant differences between various cat populations. Escherichia coli, Enterococcus faecalis, E. faecium and Streptococcus canis were isolated as faecal indicator bacteria from rectal swabs of 47 individually owned cats, 47 cattery cats and 18 hospitalised cats, and submitted through antimicrobial sensitivity tests. The results revealed that bacteria isolated from hospitalised and/or cattery cats were more frequently resistant than those from individually owned cats. E. coli isolates from hospitalised cats were particularly resistant to ampicillin, tetracycline and sulfonamide. Both enterococci and streptococci showed high resistance to tetracycline and in somewhat lesser extent to erythromycin and tylosin. Most E. faecium isolates were resistant to lincomycin and penicillin. One E. faecalis as well as one E. faecium isolate from hospitalised cats showed 'high-level resistance' (MIC > 500 microg/ml) against gentamicin, a commonly used antimicrobial agent in case of human enterococcal infections. The results of this research demonstrate that the extent of acquired antimicrobial resistance in the intestinal microbiota of cats depends on the social environment of the investigated population. It is obvious that the flora of healthy cats may act as a reservoir of resistance genes. PMID:16330058

  8. Genomic Insights into Intrinsic and Acquired Drug Resistance Mechanisms in Achromobacter xylosoxidans

    PubMed Central

    Hu, Yongfei; Zhu, Yuying; Ma, Yanan; Liu, Fei; Lu, Na; Yang, Xi; Luan, Chunguang; Yi, Yong

    2014-01-01

    Achromobacter xylosoxidans is an opportunistic pathogen known to be resistant to a wide range of antibiotics; however, the knowledge about the drug resistance mechanisms is limited. We used a high-throughput sequencing approach to sequence the genomes of the A. xylosoxidans type strain ATCC 27061 and a clinical isolate, A. xylosoxidans X02736, and then we used different bioinformatics tools to analyze the drug resistance genes in these bacteria. We obtained the complete genome sequence for A. xylosoxidans ATCC 27061 and the draft sequence for X02736. We predicted a total of 50 drug resistance-associated genes in the type strain, including 5 genes for β-lactamases and 17 genes for efflux pump systems; these genes are also conserved among other A. xylosoxidans genomes. In the clinical isolate, except for the conserved resistance genes, we also identified several acquired resistance genes carried by a new transposon embedded in a novel integrative and conjugative element. Our study provides new insights into the intrinsic and acquired drug resistance mechanisms in A. xylosoxidans, which will be helpful for better understanding the physiology of A. xylosoxidans and the evolution of antibiotic resistance in this bacterium. PMID:25487802

  9. Community-acquired methicillin-resistant Staphylococcus aureus in Central Australia.

    PubMed

    Stevens, Claire L; Ralph, Anna; McLeod, James E T; McDonald, Malcolm I

    2006-01-01

    To date, there has been scant information about the burden of methicillin-resistant Staphylococcus aureus infections in Central Australia. Our aims were to determine the proportion of Staphylococcus aureus infections due to methicillin-resistant strains in Central Australia, to characterise resistance to non-beta lactam antibiotics and to correlate findings with available demographic information. We retrospectively reviewed S. aureus isolates identified by the Microbiology Laboratory of the Pathology Department, Alice Springs Hospital between September 2005 and February 2006. Multi-resistance was defined as resistance to three or more non-beta lactam antibiotics. We identified the recovery site and extended antibiotic resistance profile of each isolate. Demographic data included place of residence, discharge diagnosis and ethnicity. There were 524 S. aureus isolates: 417 (79.6%) methicillin-sensitive S. aureus, 104 (19.7%) non-multi-resistant MRSA (nmrMRSA) and 3 (0.7%) multi-resistant MRSA (mrMRSA). MRSA accounted for 7/22 (32%) invasive infections and 91/474 (19.2%) cases of staphylococcal skin infections. Aboriginal people comprised 89 per cent (93/104) of patients with nmrMRSA; 57 per cent lived in remote communities, 21 per cent in suburban Alice Springs, and 18 per cent in Alice Springs Town Camps. Six per cent (6/104) of nmrMRSA were hospital-acquired. Of the nmrMRSA isolates, 57 per cent (59/104) were resistant to erythromycin and 7 per cent (7/104) to fusidic acid. All MRSA isolates were susceptible to co-trimoxazole. In conclusion, Central Australia has high rates of community-acquired nmrMRSA and low rates of multi-resistant MRSA. Erythromycin resistance in S. aureus is also common. These findings should prompt the review of antimicrobial prescribing guidelines for the region, especially for treatment of skin and soft tissue infections.

  10. CIPROFLOXACIN RESISTANCE PATTERN AMONG BACTERIA ISOLATED FROM PATIENTS WITH COMMUNITY-ACQUIRED URINARY TRACT INFECTION

    PubMed Central

    REIS, Ana Carolina Costa; SANTOS, Susana Regia da Silva; de SOUZA, Siane Campos; SALDANHA, Milena Góes; PITANGA, Thassila Nogueira; OLIVEIRA, Ricardo Riccio

    2016-01-01

    SUMMARY Objective: To identify the main bacterial species associated with community-acquired urinary tract infection (UTI) and to assess the pattern of ciprofloxacin susceptibility among bacteria isolated from urine cultures. Methods: We conducted a retrospective study in all the patients with community-acquired UTI seen in Santa Helena Laboratory, Camaçari, Bahia, Brazil during five years (2010-2014). All individuals who had a positive urine culture result were included in this study. Results: A total of 1,641 individuals met the inclusion criteria. Despite the fact that participants were female, we observed a higher rate of resistance to ciprofloxacin in males. The most frequent pathogens identified in urine samples were Escherichia coli, Klebsiella pneumoniae and Staphylococcus saprophyticus. Antimicrobial resistance has been observed mainly for ampicillin, sulfamethoxazole + trimethoprim and ciprofloxacin. Moreover, E. coli has shown the highest rate of ciprofloxacin resistance, reaching 36% of ciprofloxacin resistant strains in 2014. Conclusion: The rate of bacterial resistance to ciprofloxacin observed in the studied population is much higher than expected, prompting the need for rational use of this antibiotic, especially in infections caused by E. coli. Prevention of bacterial resistance can be performed through control measures to limit the spread of resistant microorganisms and a rational use of antimicrobial policy. PMID:27410913

  11. Benzothiadiazole, a novel class of inducers of systemic acquired resistance, activates gene expression and disease resistance in wheat.

    PubMed Central

    Görlach, J; Volrath, S; Knauf-Beiter, G; Hengy, G; Beckhove, U; Kogel, K H; Oostendorp, M; Staub, T; Ward, E; Kessmann, H; Ryals, J

    1996-01-01

    Systemic acquired resistance is an important component of the disease resistance repertoire of plants. In this study, a novel synthetic chemical, benzo(1,2,3)thiadiazole-7-carbothioic acid S-methyl ester (BTH), was shown to induce acquired resistance in wheat. BTH protected wheat systemically against powdery mildew infection by affecting multiple steps in the life cycle of the pathogen. The onset of resistance was accompanied by the induction of a number of newly described wheat chemically induced (WCI) genes, including genes encoding a lipoxygenase and a sulfur-rich protein. With respect to both timing and effectiveness, a tight correlation existed between the onset of resistance and the induction of the WCI genes. Compared with other plant activators, such as 2,6-dichloroisonicotinic acid and salicylic acid, BTH was the most potent inducer of both resistance and gene induction. BTH is being developed commercially as a novel type of plant protection compound that works by inducing the plant's inherent disease resistance mechanisms. PMID:8624439

  12. Amphibians acquire resistance to live and dead fungus overcoming fungal immunosuppression.

    PubMed

    McMahon, Taegan A; Sears, Brittany F; Venesky, Matthew D; Bessler, Scott M; Brown, Jenise M; Deutsch, Kaitlin; Halstead, Neal T; Lentz, Garrett; Tenouri, Nadia; Young, Suzanne; Civitello, David J; Ortega, Nicole; Fites, J Scott; Reinert, Laura K; Rollins-Smith, Louise A; Raffel, Thomas R; Rohr, Jason R

    2014-07-10

    Emerging fungal pathogens pose a greater threat to biodiversity than any other parasitic group, causing declines of many taxa, including bats, corals, bees, snakes and amphibians. Currently, there is little evidence that wild animals can acquire resistance to these pathogens. Batrachochytrium dendrobatidis is a pathogenic fungus implicated in the recent global decline of amphibians. Here we demonstrate that three species of amphibians can acquire behavioural or immunological resistance to B. dendrobatidis. Frogs learned to avoid the fungus after just one B. dendrobatidis exposure and temperature-induced clearance. In subsequent experiments in which B. dendrobatidis avoidance was prevented, the number of previous exposures was a negative predictor of B. dendrobatidis burden on frogs and B. dendrobatidis-induced mortality, and was a positive predictor of lymphocyte abundance and proliferation. These results suggest that amphibians can acquire immunity to B. dendrobatidis that overcomes pathogen-induced immunosuppression and increases their survival. Importantly, exposure to dead fungus induced a similar magnitude of acquired resistance as exposure to live fungus. Exposure of frogs to B. dendrobatidis antigens might offer a practical way to protect pathogen-naive amphibians and facilitate the reintroduction of amphibians to locations in the wild where B. dendrobatidis persists. Moreover, given the conserved nature of vertebrate immune responses to fungi and the fact that many animals are capable of learning to avoid natural enemies, these results offer hope that other wild animal taxa threatened by invasive fungi might be rescued by management approaches based on herd immunity.

  13. Erlotinib

    MedlinePlus

    ... XR); clarithromycin (Biaxin); HIV protease inhibitors such as atazanavir (Reyataz), indinavir (Crixivan), nelfinavir (Viracept), ritonavir (Norvir), and ... it at room temperature and away from excess heat and moisture (not in the bathroom).Unneeded medications ...

  14. A case of cavernous sinus thrombosis with meningitis caused by community acquired methicillin resistant Staphylococcus aureus.

    PubMed

    Dinaker, Manjunath; Sharabu, Chandrahasa; Kattula, Sri Rama Surya Tez; Kommalapati, Varun

    2014-05-01

    Septic cavernous sinus thrombosis is a rare clinical condition. Although Staphylococcus aureus is the most common pathogen causing septic cavernous sinus thrombosis [CST], it is an uncommon cause of meningitis. We report the first case of CST with meningitis in Hyderabad, Andhra Pradesh, caused by community acquired epidemic strain of Methicillin resistant staphylococcus aureus [MRSA], in a previously healthy individual with no risk factors. The patient recovered completely following treatment with Vancomycin. We consecutively reviewed all cases of community acquired staphylococcus aureus [CA-MRSA] with central nervous system involvement available in literature. PMID:25508014

  15. A case of cavernous sinus thrombosis with meningitis caused by community acquired methicillin resistant Staphylococcus aureus.

    PubMed

    Dinaker, Manjunath; Sharabu, Chandrahasa; Kattula, Sri Rama Surya Tez; Kommalapati, Varun

    2014-05-01

    Septic cavernous sinus thrombosis is a rare clinical condition. Although Staphylococcus aureus is the most common pathogen causing septic cavernous sinus thrombosis [CST], it is an uncommon cause of meningitis. We report the first case of CST with meningitis in Hyderabad, Andhra Pradesh, caused by community acquired epidemic strain of Methicillin resistant staphylococcus aureus [MRSA], in a previously healthy individual with no risk factors. The patient recovered completely following treatment with Vancomycin. We consecutively reviewed all cases of community acquired staphylococcus aureus [CA-MRSA] with central nervous system involvement available in literature. PMID:25438497

  16. Characterization of in vivo-acquired resistance to macrolides of Mycoplasma gallisepticum strains isolated from poultry.

    PubMed

    Gerchman, Irena; Levisohn, Sharon; Mikula, Inna; Manso-Silván, Lucía; Lysnyansky, Inna

    2011-01-01

    The macrolide class of antibiotics, including tylosin and tilmicosin, is widely used in the veterinary field for prophylaxis and treatment of mycoplasmosis. In vitro susceptibility testing of 50 strains of M. gallisepticum isolated in Israel during the period 1997-2010 revealed that acquired resistance to tylosin as well as to tilmicosin was present in 50% of them. Moreover, 72% (13/18) of the strains isolated from clinical samples since 2006 showed acquired resistance to enrofloxacin, tylosin and tilmicosin. Molecular typing of the field isolates, performed by gene-target sequencing (GTS), detected 13 molecular types (I-XIII). Type II was the predominant type prior to 2006 whereas type X, first detected in 2008, is currently prevalent. All ten type X strains were resistant to both fluoroquinolones and macrolides, suggesting selective pressure leading to clonal dissemination of resistance. However, this was not a unique event since resistant strains with other GTS molecular types were also found. Concurrently, the molecular basis for macrolide resistance in M. gallisepticum was identified. Our results revealed a clear-cut correlation between single point mutations A2058G or A2059G in domain V of the gene encoding 23S rRNA (rrnA, MGA_01) and acquired macrolide resistance in M. gallisepticum. Indeed, all isolates with MIC ≥ 0.63 μg/mL to tylosin and with MIC ≥ 1.25 μg/mL to tilmicosin possess one of these mutations, suggesting an essential role in decreased susceptibility of M. gallisepticum to 16-membered macrolides. PMID:21810258

  17. Characterization of in vivo-acquired resistance to macrolides of Mycoplasma gallisepticum strains isolated from poultry

    PubMed Central

    2011-01-01

    The macrolide class of antibiotics, including tylosin and tilmicosin, is widely used in the veterinary field for prophylaxis and treatment of mycoplasmosis. In vitro susceptibility testing of 50 strains of M. gallisepticum isolated in Israel during the period 1997-2010 revealed that acquired resistance to tylosin as well as to tilmicosin was present in 50% of them. Moreover, 72% (13/18) of the strains isolated from clinical samples since 2006 showed acquired resistance to enrofloxacin, tylosin and tilmicosin. Molecular typing of the field isolates, performed by gene-target sequencing (GTS), detected 13 molecular types (I-XIII). Type II was the predominant type prior to 2006 whereas type X, first detected in 2008, is currently prevalent. All ten type X strains were resistant to both fluoroquinolones and macrolides, suggesting selective pressure leading to clonal dissemination of resistance. However, this was not a unique event since resistant strains with other GTS molecular types were also found. Concurrently, the molecular basis for macrolide resistance in M. gallisepticum was identified. Our results revealed a clear-cut correlation between single point mutations A2058G or A2059G in domain V of the gene encoding 23S rRNA (rrnA, MGA_01) and acquired macrolide resistance in M. gallisepticum. Indeed, all isolates with MIC ≥ 0.63 μg/mL to tylosin and with MIC ≥ 1.25 μg/mL to tilmicosin possess one of these mutations, suggesting an essential role in decreased susceptibility of M. gallisepticum to 16-membered macrolides. PMID:21810258

  18. Transcriptome Analysis Reveals Mechanisms by Which Lactococcus lactis Acquires Nisin Resistance

    PubMed Central

    Kramer, Naomi E.; van Hijum, Sacha A. F. T.; Knol, Jan; Kok, Jan; Kuipers, Oscar P.

    2006-01-01

    Nisin, a posttranslationally modified antimicrobial peptide produced by Lactococcus lactis, is widely used as a food preservative. Yet, the mechanisms leading to the development of nisin resistance in bacteria are poorly understood. We used whole-genome DNA microarrays of L. lactis IL1403 to identify the factors underlying acquired nisin resistance mechanisms. The transcriptomes of L. lactis IL1403 and L. lactis IL1403 Nisr, which reached a 75-fold higher nisin resistance level, were compared. Differential expression was observed in genes encoding proteins that are involved in cell wall biosynthesis, energy metabolism, fatty acid and phospholipid metabolism, regulatory functions, and metal and/or peptide transport and binding. These results were further substantiated by showing that several knockout and overexpression mutants of these genes had strongly altered nisin resistance levels and that some knockout strains could no longer become resistant to the same level of nisin as that of the wild-type strain. The acquired nisin resistance mechanism in L. lactis is complex, involving various different mechanisms. The four major mechanisms are (i) preventing nisin from reaching the cytoplasmic membrane, (ii) reducing the acidity of the extracellular medium, thereby stimulating the binding of nisin to the cell wall, (iii) preventing the insertion of nisin into the membrane, and (iv) possibly transporting nisin across the membrane or extruding nisin out of the membrane. PMID:16641446

  19. Overcoming acquired BRAF inhibitor resistance in melanoma via targeted inhibition of Hsp90 with ganetespib.

    PubMed

    Acquaviva, Jaime; Smith, Donald L; Jimenez, John-Paul; Zhang, Chaohua; Sequeira, Manuel; He, Suqin; Sang, Jim; Bates, Richard C; Proia, David A

    2014-02-01

    Activating BRAF kinase mutations serve as oncogenic drivers in over half of all melanomas, a feature that has been exploited in the development of new molecularly targeted approaches to treat this disease. Selective BRAF(V600E) inhibitors, such as vemurafenib, typically induce initial, profound tumor regressions within this group of patients; however, durable responses have been hampered by the emergence of drug resistance. Here, we examined the activity of ganetespib, a small-molecule inhibitor of Hsp90, in melanoma lines harboring the BRAF(V600E) mutation. Ganetespib exposure resulted in the loss of mutant BRAF expression and depletion of mitogen-activated protein kinase and AKT signaling, resulting in greater in vitro potency and antitumor efficacy compared with targeted BRAF and MAP-ERK kinase (MEK) inhibitors. Dual targeting of Hsp90 and BRAF(V600E) provided combinatorial benefit in vemurafenib-sensitive melanoma cells in vitro and in vivo. Importantly, ganetespib overcame mechanisms of intrinsic and acquired resistance to vemurafenib, the latter of which was characterized by reactivation of extracellular signal-regulated kinase (ERK) signaling. Continued suppression of BRAF(V600E) by vemurafenib potentiated sensitivity to MEK inhibitors after acquired resistance had been established. Ganetespib treatment reduced, but not abolished, elevations in steady-state ERK activity. Profiling studies revealed that the addition of a MEK inhibitor could completely abrogate ERK reactivation in the resistant phenotype, with ganetespib displaying superior combinatorial activity over vemurafenib. Moreover, ganetespib plus the MEK inhibitor TAK-733 induced tumor regressions in vemurafenib-resistant xenografts. Overall these data highlight the potential of ganetespib as a single-agent or combination treatment in BRAF(V600E)-driven melanoma, particularly as a strategy to overcome acquired resistance to selective BRAF inhibitors. PMID:24398428

  20. [A mathematical model for the chemical control of Aedes aegypti (Diptera: Culicidae) having acquired chemical resistance].

    PubMed

    Restrepo-Alape, Leonardo D; Toro-Zapata, Hernán D; Muñoz-Loaiza, Aníbal

    2010-12-01

    Dengue fever is a common vector-borne disease in tropical and subtropical areas. It is transmitted to humans by the bite of an infected female Aedes mosquito. Since no vaccines are currently available which can protect against infection, disease control relies on controlling the mosquito population. This work was aimed at modelling such mosquito's population dynamics regarding chemical control of the adult population and its acquired resistance to chemicals. The model was analysed by using classical dynamic system theory techniques and mosquito growth threshold was determined as this establishes when a particular population may prosper in the environment or when it is likely to disappear. A suitable chemical control strategy was developed from such threshold. Simulations were made in control and non-control scenarios; this determined the degree of control application effectiveness against different levels of acquired resistance.

  1. [A mathematical model for the chemical control of Aedes aegypti (Diptera: Culicidae) having acquired chemical resistance].

    PubMed

    Restrepo-Alape, Leonardo D; Toro-Zapata, Hernán D; Muñoz-Loaiza, Aníbal

    2010-12-01

    Dengue fever is a common vector-borne disease in tropical and subtropical areas. It is transmitted to humans by the bite of an infected female Aedes mosquito. Since no vaccines are currently available which can protect against infection, disease control relies on controlling the mosquito population. This work was aimed at modelling such mosquito's population dynamics regarding chemical control of the adult population and its acquired resistance to chemicals. The model was analysed by using classical dynamic system theory techniques and mosquito growth threshold was determined as this establishes when a particular population may prosper in the environment or when it is likely to disappear. A suitable chemical control strategy was developed from such threshold. Simulations were made in control and non-control scenarios; this determined the degree of control application effectiveness against different levels of acquired resistance. PMID:22030690

  2. Community-acquired methicillin-resistant Staphylococcus aureus in a group home setting.

    PubMed

    Collins, Rebeccah J

    2007-09-01

    Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) is an infection involving methicillin-resistant Staphylococcus aureus (MRSA) with onset in the community in an individual lacking established health care-associated MRSA risk factors. A 74-year-old group home resident with a history of hypertension and mental retardation presents with a spider bite-like lesion that rapidly progresses to multiple areas of her body. Culture results reveal MRSA. The patient's advanced age and the severity and rapidity of progression of the condition warranted treatment, and options are discussed. Pharmacists should assist in selecting antibiotics for patients with resistant infections and provide strategies for preventing the spread of resistant organisms. Current and complete medical records are critical in the group home setting. The role of the caregiver and the consultant pharmacist in this setting is discussed.

  3. Naturally occurring dominant drug resistance mutations occur infrequently in the setting of recently acquired hepatitis C

    PubMed Central

    Applegate, Tanya L; Gaudieri, Silvana; Plauzolles, Anne; Chopra, Abha; Grebely, Jason; Lucas, Michaela; Hellard, Margaret; Luciani, Fabio; Dore, Gregory J; Matthews, Gail V

    2014-01-01

    Background Directly Acting Antivirals (DAAs) are predicted to transform hepatitis C (HCV) therapy, yet little is known about the prevalence of naturally occurring resistance mutations in recently acquired HCV. This study aimed to determine the prevalence and frequency of drug resistance mutations in the viral quasispecies among HIV positive and negative individuals with recent HCV. Methods The NS3 protease, NS5A and NS5B polymerase genes were amplified from fifty genotype 1a participants of the Australian Trial in Acute Hepatitis C. Amino acid variations at sites known to be associated with possible drug resistance were analysed by ultra-deep pyrosequencing. Results Twelve percent of individuals harboured dominant resistance mutations, while 36% demonstrated non dominant resistant variants below that detectable by bulk sequencing (ie < 20%) but above a threshold of 1%. Resistance variants (< 1%) were observed at most sites associated with DAA resistance from all classes, with the exception of sofosbuvir. Conclusions Dominant resistant mutations were uncommonly observed in the setting of recent HCV. However, low level mutations to all DAA classes were observed by deep sequencing at the majority of sites, and in most individuals. The significance of these variants and impact on future treatment options remains to be determined. PMID:25105742

  4. Disseminated cryptococcosis and fluconazole resistant oral candidiasis in a patient with acquired immunodeficiency syndrome (AIDS).

    PubMed

    Kothavade, Rajendra J; Oberai, Chetan M; Valand, Arvind G; Panthaki, Mehroo H

    2010-10-28

    Disseminated cryptococcosis and recurrent oral candidiasis was presented in a-heterosexual AIDS patient. Candida tropicalis (C.tropicalis) was isolated from the oral pseudomembranous plaques and Cryptococcus neoformans (C. neoformans) was isolated from maculopapular lesions on body parts (face, hands and chest) and body fluids (urine, expectorated sputum, and cerebrospinal fluid). In vitro drug susceptibility testing on the yeast isolates demonstrated resistance to fluconazole acquired by C. tropicalis which was a suggestive possible root cause of recurrent oral candidiasis in this patient.

  5. Community-acquired methicillin resistant Staphylococcus aureus in a women's collegiate basketball team.

    PubMed

    Stevens, Michael P; Bearman, Gonzalo; Rosato, Adriana; Edmond, Michael

    2008-10-01

    Community-acquired methicillin resistant Staphylococcus aureus (CA-MRSA) infections are becoming increasingly frequent, and cutaneous disease with this organism is often seen in otherwise healthy organized sports participants. A case of CA-MRSA skin and soft tissue infection in a female collegiate basketball player is presented, and screening and management of her team is discussed. Interestingly, multiple MRSA strains were discovered on testing of the team, raising concern that the prevalence of colonization in this population may be high.

  6. Successful treatment of non-small-cell lung cancer with afatinib and a glucocorticoid following gefitinib- and erlotinib-induced interstitial lung disease: A case report

    PubMed Central

    Tani, Tetsuo; Naoki, Katsuhiko; Asakura, Takanori; Hirano, Toshiyuki; Suzuki, Shoji; Masuzawa, Keita; Hasegawa, Hanako; Kuroda, Aoi; Yasuda, Hiroyuki; Ishii, Makoto; Soejima, Kenzo; Betsuyaku, Tomoko

    2016-01-01

    Epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI)-induced interstitial lung disease (ILD) may be a life-threatening condition that may develop during treatment of lung cancer patients harboring EGFR mutations. We herein present the case of a 41-year-old female patient diagnosed with lung adenocarcinoma with an EGFR mutation (exon 19 deletion). The patient was treated with gefitinib followed by erlotinib and developed ILD induced by both EGFR-TKIs; furthermore, the patient acquired resistance to EGFR-TKI treatment. A repeat biopsy revealed a T790M mutation, which is associated with resistance to first-generation EGFR-TKIs, along with an exon 19 deletion identified by cytology of the pleural fluid. Treatment with afatinib and prednisolone resulted in tumor shrinkage, without worsening of the ILD. The present case demonstrated that combination treatment with afatinib and a glucocorticoid may be effective for the treatment of lung cancer patients who develop EGFR-TKI-induced ILD.

  7. Multidrug-resistant, extensively drug-resistant and pandrug-resistant bacteria: an international expert proposal for interim standard definitions for acquired resistance.

    PubMed

    Magiorakos, A-P; Srinivasan, A; Carey, R B; Carmeli, Y; Falagas, M E; Giske, C G; Harbarth, S; Hindler, J F; Kahlmeter, G; Olsson-Liljequist, B; Paterson, D L; Rice, L B; Stelling, J; Struelens, M J; Vatopoulos, A; Weber, J T; Monnet, D L

    2012-03-01

    Many different definitions for multidrug-resistant (MDR), extensively drug-resistant (XDR) and pandrug-resistant (PDR) bacteria are being used in the medical literature to characterize the different patterns of resistance found in healthcare-associated, antimicrobial-resistant bacteria. A group of international experts came together through a joint initiative by the European Centre for Disease Prevention and Control (ECDC) and the Centers for Disease Control and Prevention (CDC), to create a standardized international terminology with which to describe acquired resistance profiles in Staphylococcus aureus, Enterococcus spp., Enterobacteriaceae (other than Salmonella and Shigella), Pseudomonas aeruginosa and Acinetobacter spp., all bacteria often responsible for healthcare-associated infections and prone to multidrug resistance. Epidemiologically significant antimicrobial categories were constructed for each bacterium. Lists of antimicrobial categories proposed for antimicrobial susceptibility testing were created using documents and breakpoints from the Clinical Laboratory Standards Institute (CLSI), the European Committee on Antimicrobial Susceptibility Testing (EUCAST) and the United States Food and Drug Administration (FDA). MDR was defined as acquired non-susceptibility to at least one agent in three or more antimicrobial categories, XDR was defined as non-susceptibility to at least one agent in all but two or fewer antimicrobial categories (i.e. bacterial isolates remain susceptible to only one or two categories) and PDR was defined as non-susceptibility to all agents in all antimicrobial categories. To ensure correct application of these definitions, bacterial isolates should be tested against all or nearly all of the antimicrobial agents within the antimicrobial categories and selective reporting and suppression of results should be avoided.

  8. Acquired platinum resistance involves epithelial to mesenchymal transition through ubiquitin ligase FBXO32 dysregulation

    PubMed Central

    Tanaka, Nobuyuki; Miyazaki, Yasumasa; Mikami, Shuji; Niwa, Naoya; Otsuka, Yutaro; Mizuno, Ryuichi; Kikuchi, Eiji; Miyajima, Akira; Sabe, Hisataka; Okada, Yasunori; Suematsu, Makoto; Oya, Mototsugu

    2016-01-01

    To identify the molecules involved in epithelial to mesenchymal transition (EMT) in urothelial carcinoma (UC) after acquisition of platinum resistance, here we examined the changes in global gene expression before and after platinum treatment. Four invasive UC cell lines, T24, 5637, and their corresponding sublines T24PR and 5637PR with acquired platinum resistance, were assessed by microarray, and the ubiquitin E3 ligase FBXO32 was newly identified as a negative regulator of EMT in UC tumors after acquisition of platinum resistance. In vitro and in vivo studies showed an intimate relationship between FBXO32 expression and EMT, demonstrating that FBXO32 dysregulation in T24PR cells results in elevated expression of the mesenchymal molecules SNAIL and vimentin and decreased expression of the epithelial molecule E-cadherin. The association between FBXO32 expression and EMT was further validated using clinical samples. Knockdown of MyoD expression, a specific target of FBXO32 polyubiquitination, revealed upregulation of E-cadherin expression and downregulation of SNAIL and vimentin expression in T24PR cells. Comparative genomic hybridization array analysis demonstrated loss of heterozygosity at 8q24.13 in T24PR cells, which harbors FBXO32. Our findings suggest the importance of the association between EMT and ubiquitin-proteasome regulation when tumors develop acquired platinum resistance. PMID:27812537

  9. Bacteraemia and antibiotic-resistant pathogens in community acquired pneumonia: risk and prognosis.

    PubMed

    Torres, Antoni; Cillóniz, Catia; Ferrer, Miquel; Gabarrús, Albert; Polverino, Eva; Villegas, Santiago; Marco, Francesc; Mensa, Josep; Menéndez, Rosario; Niederman, Michael

    2015-05-01

    The sensitivity of blood cultures in the diagnosis of bacteraemia for community-acquired pneumonia is low. Recommendations, by guidelines, to perform blood cultures are discordant. We aimed to determine the incidence, microbial aetiology, risk factors and outcomes of bacteraemic patients with community-acquired pneumonia, including cases with antibiotic-resistant pathogens (ARP). A prospective, observational study was undertaken on consecutive adult patients admitted to the Hospital Clinic of Barcelona (Barcelona, Spain) with community-acquired pneumonia and blood cultures were obtained. Of the 2892 patients included, bacteraemia was present in 297 (10%) patients; 30 (10%) of whom had ARP (multidrug-resistant Streptococcus pneumoniae, methicillin-resistant Staphylococcus aureus, Pseudomonas aeruginosa, and an extended spectrum of beta-lactamase producing Enterobacteriaceae). In multivariate analyses, pleuritic pain, C-reactive protein ≥21.6 mg·dL(-1) and intensive care unit admissions were independently associated with bacteraemia, while prior antibiotic treatment and pneumococcal vaccine were protective factors. The risk factors for ARP bacteraemia were previous antibiotics and C-reactive protein <22.2 mg·dL(-1), while pleuritic pain was the only protective factor in the multivariate analysis. Bacteraemia (excluding ARP), appropriate empiric treatment, neurological disease, arterial oxygen tension/inspiratory oxygen fraction <250, pneumonia severity index risk classes IV and V, and intensive care unit admission were independently associated with a 30-day hospital mortality in the multivariate analysis. Inappropriate therapy was more frequent in ARP bacteraemia, compared with other bacteraemias (27% versus 3%, respectively, p<0.001). Antibiotic therapy protected against bacteraemia, but increased specifically the risk of bacteraemia from ARP due to the inappropriate coverage of these pathogens. Identifying patients at risk of ARP bacteraemia would help in

  10. Amphibians acquire resistance to live and dead fungus overcoming fungal immunosuppression

    PubMed Central

    McMahon, Taegan A.; Sears, Brittany F.; Venesky, Matthew D.; Bessler, Scott M.; Brown, Jenise M.; Deutsch, Kaitlin; Halstead, Neal T.; Lentz, Garrett; Tenouri, Nadia; Young, Suzanne; Civitello, David J.; Ortega, Nicole; Fites, J. Scott; Reinert, Laura K.; Rollins-Smith, Louise A.; Raffel, Thomas R.; Rohr, Jason R.

    2015-01-01

    Emerging fungal pathogens pose a greater threat to biodiversity than any other parasitic group1, causing declines of many taxa, including bats, corals, bees, snakes and amphibians1–4. Currently, there is little evidence that wild animals can acquire resistance to these pathogens5. Batrachochytrium dendrobatidis is a pathogenic fungus implicated in the recent global decline of amphibians6. Here we demonstrate that three species of amphibians can acquire behavioural or immunological resistance to B. dendrobatidis. Frogs learned to avoid the fungus after just one B. dendrobatidis exposure and temperature-induced clearance. In subsequent experiments in which B. dendrobatidis avoidance was prevented, the number of previous exposures was a negative predictor of B. dendrobatidis burden on frogs and B. dendrobatidis-induced mortality, and was a positive predictor of lymphocyte abundance and proliferation. These results suggest that amphibians can acquire immunity to B. dendrobatidis that overcomes pathogen-induced immunosuppression7–9 and increases their survival. Importantly, exposure to dead fungus induced a similar magnitude of acquired resistance as exposure to live fungus. Exposure of frogs to B. dendrobatidis antigens might offer a practical way to protect pathogen-naive amphibians and facilitate the reintroduction of amphibians to locations in the wild where B. dendrobatidis persists. Moreover, given the conserved nature of vertebrate immune responses to fungi5 and the fact that many animals are capable of learning to avoid natural enemies10, these results offer hope that other wild animal taxa threatened by invasive fungi might be rescued by management approaches based on herd immunity. PMID:25008531

  11. IGF-1R/epithelial-to-mesenchymal transition (EMT) crosstalk suppresses the erlotinib-sensitizing effect of EGFR exon 19 deletion mutations

    PubMed Central

    Vazquez-Martin, Alejandro; Cufí, Sílvia; Oliveras-Ferraros, Cristina; Torres-Garcia, Violeta Zenobia; Corominas-Faja, Bruna; Cuyàs, Elisabet; Bonavia, Rosa; Visa, Joana; Martin-Castillo, Begoña; Barrajón-Catalán, Enrique; Micol, Vicente; Bosch-Barrera, Joaquim; Menendez, Javier A.

    2013-01-01

    Using non-small cell lung carcinoma (NSCLC) cells harboring the erlotinib-sensitizing Epidermal Growth Factor Receptor (EGFR) exon 19 mutation delE746-A750, we developed erlotinib-refractory derivatives in which hyperactive Insulin-like Growth Factor-1 Receptor (IGF-1R) signaling associated with enrichment in epithelial-to-mesenchymal transition (EMT)-related morphological and transcriptional features. We then explored whether an IGF-1R/EMT crosstalk was sufficient to promote erlotinib refractoriness in the absence of second-site EGFR mutations, MET and AXL hyperactivation. Transforming Growth Factor-beta1 (TGFβ1)-induced mesenchymal trans-differentiation was sufficient to impede erlotinib functioning in the presence of drug-sensitive delE746-A750 EGFR mutation. Pharmacological blockade of IGF-1R fully prevented the TGFβ1's ability to activate an EMT protein signature [E-cadherin low/vimentin high]. The sole presence of erlotinib was capable of rapidly activate an IGF-1R-dependent, vimentin-enriched mesenchymal-like phenotype in delE746-A750-mutated epithelial cells. Even if transient, NSCLC cells' intrinsic plasticity to undergo crosstalk between IGF-1R and EMT signaling pathways can sufficiently eliminate the erlotinib-sensitizing effect of highly prevalent EGFR mutations and suggests the urgent need for dual IGF-1R/EMT-targeting strategies to circumvent erlotinib resistance. PMID:23994953

  12. Sentinel cases of community-acquired methicillin-resistant Staphylococcus aureus onboard a naval ship.

    PubMed

    LaMar, James E; Carr, Russell B; Zinderman, Craig; McDonald, Kimberly

    2003-02-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is emerging as a community-acquired organism. A number of recent reports have documented its involvement in a variety of infections in which no risk factors for nosocomial transmission are present. This report presents the initial cases of a MRSA outbreak on a U.S. Navy ship. Each patient failed traditional antibiotic therapy and one required hospitalization. Their presentations evolved simultaneously and proved to be sentinel cases of an outbreak of cutaneous MRSA infections. The events of this outbreak emphasize the growing need to consider the prevalence of resistant organisms in outpatient settings, as well as the impact that infections from resistant organisms might have on the combat readiness of a military unit. Recommendations addressing infection-control guidelines for MRSA within close-quarter environments of healthy adults, such as military units, need to be developed and existing infection-control measures need to be regularly emphasized.

  13. Antimicrobial Resistance in Hospital-Acquired Gram-Negative Bacterial Infections

    PubMed Central

    Mehrad, Borna; Clark, Nina M.; Zhanel, George G.

    2015-01-01

    Aerobic gram-negative bacilli, including the family of Enterobacteriaceae and non-lactose fermenting bacteria such as Pseudomonas and Acinetobacter species, are major causes of hospital-acquired infections. The rate of antibiotic resistance among these pathogens has accelerated dramatically in recent years and has reached pandemic scale. It is no longer uncommon to encounter gram-negative infections that are untreatable using conventional antibiotics in hospitalized patients. In this review, we provide a summary of the major classes of gram-negative bacilli and their key mechanisms of antimicrobial resistance, discuss approaches to the treatment of these difficult infections, and outline methods to slow the further spread of resistance mechanisms. PMID:25940252

  14. ACE2 overexpression inhibits acquired platinum resistance-induced tumor angiogenesis in NSCLC.

    PubMed

    Cheng, Qijian; Zhou, Ling; Zhou, Jianping; Wan, Huanying; Li, Qingyun; Feng, Yun

    2016-09-01

    Angiotensin II (AngII) is a multifunctional bioactive peptide in the renin-angiotensin system (RAS). Angiotensin-converting enzyme 2 (ACE2) is a newly identified component of RAS. We previously reported that ACE2 overexpression may inhibit cell growth and vascular endothelial growth factor (VEGF) production in vitro and in vivo. In the present study, we investigated the effect of ACE2 on tumor-associated angiogen-esis after the development of acquired platinum resistance in non-small cell lung cancer (NSCLC). Four NSCLC cell lines, A549, LLC, A549-DDP and LLC-DDP, were used in vitro, while A549 and A549-DDP cells were used in vivo. A549-DDP and LLC-DDP cells were newly established at our institution as acquired platinum-resistant sublines by culturing the former parent cells in cisplatin (CDDP)-containing conditioned medium for 6 months. These platinum-resistant cells showed significantly higher angiotensin II type 1 receptor (AT1R), ACE and VEGF production and lower ACE2 expression than their corresponding parent cells. We showed that ACE2 overexpression inhibited the production of VEGF in vitro and in vivo compared to their corresponding parent cells. We also found that ACE2 overexpression reduced the expression of AT1R and ACE. Additionally, we confirmed that ACE2 overexpres-sion inhibited cell growth and VEGF production while simultaneously suppressing ACE and AT1R expression in human lung cancer xenografts. Our findings indicate that ACE2 overexpression may potentially suppress angiogenesis in NSCLC after the development of acquired platinum resistance. PMID:27460845

  15. Multidrug efflux pumps as main players in intrinsic and acquired resistance to antimicrobials.

    PubMed

    Hernando-Amado, Sara; Blanco, Paula; Alcalde-Rico, Manuel; Corona, Fernando; Reales-Calderón, Jose A; Sánchez, María B; Martínez, José L

    2016-09-01

    Multidrug efflux pumps constitute a group of transporters that are ubiquitously found in any organism. In addition to other functions with relevance for the cell physiology, efflux pumps contribute to the resistance to compounds used for treating different diseases, including resistance to anticancer drugs, antibiotics or antifungal compounds. In the case of antimicrobials, efflux pumps are major players in both intrinsic and acquired resistance to drugs currently in use for the treatment of infectious diseases. One important aspect not fully explored of efflux pumps consists on the identification of effectors able to induce their expression. Indeed, whereas the analysis of clinical isolates have shown that mutants overexpressing these resistance elements are frequently found, less is known on the conditions that may trigger expression of efflux pumps, hence leading to transient induction of resistance in vivo, a situation that is barely detectable using classical susceptibility tests. In the current article we review the structure and mechanisms of regulation of the expression of bacterial and fungal efflux pumps, with a particular focus in those for which a role in clinically relevant resistance has been reported. PMID:27620952

  16. The changing face of community-acquired methicillin-resistant Staphylococcus aureus.

    PubMed

    Kale, P; Dhawan, B

    2016-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is an important cause of infection, both in hospitalised patients with significant healthcare exposure and in patients without healthcare risk factors. Community-acquired methicillin-resistant S. aureus (CA-MRSA) are known for their rapid community transmission and propensity to cause aggressive skin and soft tissue infections and community-acquired pneumonia. The distinction between the healthcare-associated (HA)-MRSA and CA-MRSA is gradually fading owing to the acquisition of multiple virulence factors and genetic elements. The movement of CA-MRSA strains into the nosocomial setting limits the utility of using clinical risk factors alone to designate community or HA status. Identification of unique genetic characteristics and genotyping are valuable tools for MRSA epidemiological studies. Although the optimum pharmacotherapy for CA-MRSA infections has not been determined, many CA-MRSA strains remain broadly susceptible to several non-β-lactam antibacterial agents. This review aimed at illuminating the characteristic features of CA-MRSA, virulence factors, changing clinical settings and molecular epidemiology, insurgence into the hospital settings and therapy with drug resistance. PMID:27514947

  17. The changing face of community-acquired methicillin-resistant Staphylococcus aureus.

    PubMed

    Kale, P; Dhawan, B

    2016-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is an important cause of infection, both in hospitalised patients with significant healthcare exposure and in patients without healthcare risk factors. Community-acquired methicillin-resistant S. aureus (CA-MRSA) are known for their rapid community transmission and propensity to cause aggressive skin and soft tissue infections and community-acquired pneumonia. The distinction between the healthcare-associated (HA)-MRSA and CA-MRSA is gradually fading owing to the acquisition of multiple virulence factors and genetic elements. The movement of CA-MRSA strains into the nosocomial setting limits the utility of using clinical risk factors alone to designate community or HA status. Identification of unique genetic characteristics and genotyping are valuable tools for MRSA epidemiological studies. Although the optimum pharmacotherapy for CA-MRSA infections has not been determined, many CA-MRSA strains remain broadly susceptible to several non-β-lactam antibacterial agents. This review aimed at illuminating the characteristic features of CA-MRSA, virulence factors, changing clinical settings and molecular epidemiology, insurgence into the hospital settings and therapy with drug resistance.

  18. Mutational and acquired carbapenem resistance mechanisms in multidrug resistant Pseudomonas aeruginosa clinical isolates from Recife, Brazil.

    PubMed

    Cavalcanti, Felipe Lira de Sá; Mirones, Cristina Rodríguez; Paucar, Elena Román; Montes, Laura Álvarez; Leal-Balbino, Tereza Cristina; Morais, Marcia Maria Camargo de; Martínez-Martínez, Luis; Ocampo-Sosa, Alain Antonio

    2015-12-01

    An investigation was carried out into the genetic mechanisms responsible for multidrug resistance in nine carbapenem-resistant Pseudomonas aeruginosa isolates from different hospitals in Recife, Brazil. Susceptibility to antimicrobial agents was determined by broth microdilution. Polymerase chain reaction (PCR) was employed to detect the presence of genes encoding β-lactamases, aminoglycoside-modifying enzymes (AMEs), 16S rRNA methylases, integron-related genes and OprD. Expression of genes coding for efflux pumps and AmpC cephalosporinase were assessed by quantitative PCR. The outer membrane proteins were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The blaSPM-1, blaKPC-2 and blaGES-1 genes were detected in P. aeruginosa isolates in addition to different AME genes. The loss of OprD in nine isolates was mainly due to frameshift mutations, premature stop codons and point mutations. An association of loss of OprD with the overexpression of MexAB-OprM and MexXY-OprM was observed in most isolates. Hyper-production of AmpC was also observed in three isolates. Clonal relationship of the isolates was determined by repetitive element palindromic-PCR and multilocus sequence typing. Our results show that the loss of OprD along with overexpression of efflux pumps and β-lactamase production were responsible for the multidrug resistance in the isolates analysed.

  19. Mutational and acquired carbapenem resistance mechanisms in multidrug resistant Pseudomonas aeruginosa clinical isolates from Recife, Brazil

    PubMed Central

    Cavalcanti, Felipe Lira de Sá; Mirones, Cristina Rodríguez; Paucar, Elena Román; Montes, Laura Álvarez; Leal-Balbino, Tereza Cristina; de Morais, Marcia Maria Camargo; Martínez-Martínez, Luis; Ocampo-Sosa, Alain Antonio

    2015-01-01

    An investigation was carried out into the genetic mechanisms responsible for multidrug resistance in nine carbapenem-resistant Pseudomonas aeruginosaisolates from different hospitals in Recife, Brazil. Susceptibility to antimicrobial agents was determined by broth microdilution. Polymerase chain reaction (PCR) was employed to detect the presence of genes encoding β-lactamases, aminoglycoside-modifying enzymes (AMEs), 16S rRNA methylases, integron-related genes and OprD. Expression of genes coding for efflux pumps and AmpC cephalosporinase were assessed by quantitative PCR. The outer membrane proteins were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The blaSPM-1, blaKPC-2 and blaGES-1 genes were detected in P. aeruginosaisolates in addition to different AME genes. The loss of OprD in nine isolates was mainly due to frameshift mutations, premature stop codons and point mutations. An association of loss of OprD with the overexpression of MexAB-OprM and MexXY-OprM was observed in most isolates. Hyper-production of AmpC was also observed in three isolates. Clonal relationship of the isolates was determined by repetitive element palindromic-PCR and multilocus sequence typing. Our results show that the loss of OprD along with overexpression of efflux pumps and β-lactamase production were responsible for the multidrug resistance in the isolates analysed. PMID:26676375

  20. Systemic acquired resistance (50 years after discovery): moving from the lab to the field.

    PubMed

    Gozzo, Franco; Faoro, Franco

    2013-12-26

    Induction of plant defense(s) against pathogen challenge(s) has been the object of progressively more intense research in the past two decades. Insights on mechanisms of systemic acquired resistance (SAR) and similar, alternative processes, as well as on problems encountered on moving to their practical application in open field, have been carefully pursued and, as far as possible, defined. In reviewing the number of research works published in metabolomic, genetic, biochemical, and crop protection correlated disciplines, the following outline has been adopted: 1, introduction to the processes currently considered as models of the innate immunity; 2, primary signals, such as salicylic acid (SA), jasmonic acid (JA), and abscisic acid (ABA), involved with different roles in the above-mentioned processes; 3, long-distance signals, identified from petiole exudates as mobile signaling metabolites during expressed resistance; 4, exogenous inducers, including the most significant chemicals known to stimulate the plant resistance induction and originated from both synthetic and natural sources; 5, fungicides shown to act as stimulators of SAR in addition to their biocidal action; 6, elusive mechanism of priming, reporting on the most recent working hypotheses on the pretranscriptional ways through which treated plants may express resistance upon pathogen attack and how this resistance can be transmitted to the next generation; 7, fitness costs and benefits of SAR so far reported from field application of induced resistance; 8, factors affecting efficacy of induced resistance in the open field, indicating that forces, unrevealed under controlled conditions, may be operative in the field; 9, concluding remarks address the efforts required to apply the strategy of crop resistance induction according to the rules of integrated pest management.

  1. Activation of the Met kinase confers acquired drug resistance in FGFR-targeted lung cancer therapy.

    PubMed

    Kim, S-M; Kim, H; Yun, M R; Kang, H N; Pyo, K-H; Park, H J; Lee, J M; Choi, H M; Ellinghaus, P; Ocker, M; Paik, S; Kim, H R; Cho, B C

    2016-01-01

    Aberrant fibroblast growth factor receptor (FGFR) activation/expression is a common feature in lung cancer (LC). In this study, we evaluated the antitumor activity of and the mechanisms underlying acquired resistance to two potent selective FGFR inhibitors, AZD4547 and BAY116387, in LC cell lines. The antitumor activity of AZD4547 and BAY1163877 was screened in 24 LC cell lines, including 5 with FGFR1 amplification. Two cell lines containing FGFR1 amplifications, H1581 and DMS114, were sensitive to FGFR inhibitors (IC50<250 nm). Clones of FGFR1-amplified H1581 cells resistant to AZD4547 or BAY116387 (H1581AR and H1581BR cells, respectively) were established. Receptor tyrosine kinase (RTK) array and immunoblotting analyses showed strong overexpression and activation of Met in H1581AR/BR cells, compared with that in the parental cells. Gene set enrichment analysis against the Kyoto Encyclopedia of Genes and Genomes (KEGG) database showed that cytokine-cytokine receptor interaction pathways were significantly enriched in H1581AR/BR cells, with Met contributing significantly to the core enrichment. Genomic DNA quantitative PCR and fluorescent in situ hybridization analyses showed MET amplification in H1581AR, but not in H1581BR, cells. Met amplification drives acquired resistance to AZD4547 in H1581AR cells by activating ErbB3. Combination treatment with FGFR inhibitors and an anaplastic lymphoma kinase (ALK)/Met inhibitor, crizotinib, or Met-specific short interfering RNA (siRNA) synergistically inhibited cell proliferation in both H1581AR and H1581BR cells. Conversely, ectopic expression of Met in H1581 cells conferred resistance to AZD4547 and BAY1163877. Acquired resistance to FGFR inhibitors not only altered cellular morphology, but also promoted migration and invasion of resistant clones, in part by inducing epithelial-to-mesenchymal transition. Taken together, our data suggest that Met activation is sufficient to bypass dependency on FGFR signaling. Concurrent

  2. Surveillance for Travel and Domestically Acquired Multidrug-Resistant Human Shigella Infections-Pennsylvania, 2006-2014.

    PubMed

    Li, Yu Lung; Tewari, Deepanker; Yealy, Courtney C; Fardig, David; M'ikanatha, Nkuchia M

    2016-01-01

    Shigellosis is a leading cause of enteric infections in the United States. We compared antimicrobial resistance in Shigella infections related to overseas travel (travel-associated) and in those acquired domestically by analyzing antimicrobial resistance patterns, geographic distributions, and pulsed-field gel electrophoresis (PFGE) patterns. We tested samples (n = 204) from a collection of isolates recovered from patients in Pennsylvania between 2006 and 2014. Isolates were grouped into travel- and non-travel-associated categories. Eighty-one (79.4%) of the Shigella isolates acquired during international travel were resistant to multiple antibiotics compared to 53 (52.1%) of the infections transmitted in domestic settings. A majority (79.4%) of isolates associated with international travel demonstrated resistance to aminoglycosides and tetracyclines, whereas 47 (46.1%) of the infections acquired domestically were resistant to tetracycline. Almost all isolates (92.2%) transmitted in domestic settings were resistant to aminoglycosides, and 5 isolates from adult male patients were resistant to azithromycin, a drug often used for empiric treatment of severe shigellosis. Twenty (19.6%) isolates associated with illnesses acquired during overseas travel in 4 countries were resistant to quinolones. One S. sonnei PFGE pattern was traced to a multidrug-resistant isolate acquired overseas that had caused a multistate outbreak of shigellosis, suggesting global dissemination of a drug-resistant species. Resistance to certain drugs-for example, tetracycline-increased in both overseas- and domestic-acquired infections during the study period. The prevalence of resistance to macrolides (azithromycin) and third-generation cephalosporins (ceftriaxone) was less than 1%; however, efforts to better monitor changes in drug resistance over time combined with increased antimicrobial stewardship are essential at the local, national, and global levels. PMID:27314654

  3. Hospital-acquired infections due to multidrug-resistant organisms in Hungary, 2005-2010.

    PubMed

    Caini, S; Hajdu, A; Kurcz, A; Borocz, K

    2013-01-10

    Healthcare-associated infections caused by multidrug-resistant organisms are associated with prolonged medical care, worse outcome and costly therapies. In Hungary, hospital-acquired infections (HAIs) due to epidemiologically important multidrug-resistant organisms are notifiable by law since 2004. Overall, 6,845 case-patients (59.8% men; median age: 65 years) were notified in Hungary from 2005 to 2010. One third of case-patients died in hospital. The overall incidence of infections increased from 5.4 in 2005 to 14.7 per 100,000 patient-days in 2010. Meticillin-resistant Staphylococcus aureus (MRSA) was the most frequently reported pathogen (52.2%), but while its incidence seemed to stabilise after 2007, notifications of multidrug-resistant Gram-negative organisms have significantly increased from 2005 to 2010. Surgical wound and bloodstream were the most frequently reported sites of infection. Although MRSA incidence has seemingly reached a plateau in recent years, actions aiming at reducing the burden of HAIs with special focus on Gram-negative multidrug-resistant organisms are needed in Hungary. Continuing promotion of antimicrobial stewardship, infection control methodologies, reinforced HAI surveillance among healthcare and infection control practitioners, and engagement of stakeholders, hospital managers and public health authorities to facilitate the implementation of existing guidelines and protocols are essential.

  4. Fibrocyte-like cells mediate acquired resistance to anti-angiogenic therapy with bevacizumab

    PubMed Central

    Mitsuhashi, Atsushi; Goto, Hisatsugu; Saijo, Atsuro; Trung, Van The; Aono, Yoshinori; Ogino, Hirokazu; Kuramoto, Takuya; Tabata, Sho; Uehara, Hisanori; Izumi, Keisuke; Yoshida, Mitsuteru; Kobayashi, Hiroaki; Takahashi, Hidefusa; Gotoh, Masashi; Kakiuchi, Soji; Hanibuchi, Masaki; Yano, Seiji; Yokomise, Hiroyasu; Sakiyama, Shoji; Nishioka, Yasuhiko

    2015-01-01

    Bevacizumab exerts anti-angiogenic effects in cancer patients by inhibiting vascular endothelial growth factor (VEGF). However, its use is still limited due to the development of resistance to the treatment. Such resistance can be regulated by various factors, although the underlying mechanisms remain incompletely understood. Here we show that bone marrow-derived fibrocyte-like cells, defined as alpha-1 type I collagen-positive and CXCR4-positive cells, contribute to the acquired resistance to bevacizumab. In mouse models of malignant pleural mesothelioma and lung cancer, fibrocyte-like cells mediate the resistance to bevacizumab as the main producer of fibroblast growth factor 2. In clinical specimens of lung cancer, the number of fibrocyte-like cells is significantly increased in bevacizumab-treated tumours, and correlates with the number of treatment cycles, as well as CD31-positive vessels. Our results identify fibrocyte-like cells as a promising cell biomarker and a potential therapeutic target to overcome resistance to anti-VEGF therapy. PMID:26635184

  5. Radiation-resistant acquired immunity of vaccinated mice to Schistosoma mansoni

    SciTech Connect

    Aitken, R.; Coulson, P.S.; Dixon, B.; Wilson, R.A.

    1987-11-01

    Vaccination of mice with attenuated cercariae of Schistosoma mansoni induces specific acquired resistance to challenge infection. This resistance is immunologically-mediated, possibly via a delayed-type hypersensitivity. Studies of parasite migration have shown that the protective mechanism operates most effectively in the lungs of vaccinated mice. We have probed the mechanism by exposing mice to 500 rads of gamma radiation before challenge infection. Our results show that the effector mechanism operative against challenge larvae is resistant to radiation. In contrast, classical immune responses are markedly suppressed by the same treatment. While leukocyte populations in the blood fall dramatically after irradiation, numbers of cells recoverable by bronchoalveolar lavage are unaffected. We suggest that vaccination with attenuated cercariae establishes populations of sensitized cells in the lungs which trigger the mechanism of resistance when challenge schistosomula migrate through pulmonary capillary beds. Although the cells may be partially disabled by irradiation, they remain responsive to worm antigens and thereby capable of initiating the elimination mechanism. This hypothesis would explain the radiation resistance of vaccine-induced immunity to S. mansoni.

  6. Risk Factors for Acquired Rifamycin and Isoniazid Resistance: A Systematic Review and Meta-Analysis

    PubMed Central

    Rockwood, Neesha; Abdullahi, Leila H.; Wilkinson, Robert J.; Meintjes, Graeme

    2015-01-01

    Background Studies looking at acquired drug resistance (ADR) are diverse with respect to geographical distribution, HIV co-infection rates, retreatment status and programmatic factors such as regimens administered and directly observed therapy. Our objective was to examine and consolidate evidence from clinical studies of the multifactorial aetiology of acquired rifamycin and/or isoniazid resistance within the scope of a single systematic review. This is important to inform policy and identify key areas for further studies. Methods Case-control and cohort studies and randomised controlled trials that reported ADR as an outcome during antitubercular treatment regimens including a rifamycin and examined the association of at least 1 risk factor were included. Post hoc, we carried out random effects Mantel-Haenszel weighted meta-analyses of the impact of 2 key risk factors 1) HIV and 2) baseline drug resistance on the binary outcome of ADR. Heterogeneity was assessed used I2 statistic. As a secondary outcome, we calculated median cumulative incidence of ADR, weighted by the sample size of the studies. Results Meta-analysis of 15 studies showed increased risk of ADR with baseline mono- or polyresistance (RR 4.85 95% CI 3.26 to 7.23, heterogeneity I2 58%, 95% CI 26 to 76%). Meta-analysis of 8 studies showed that HIV co-infection was associated with increased risk of ADR (RR 3.02, 95% CI 1.28 to 7.11); there was considerable heterogeneity amongst these studies (I2 81%, 95% CI 64 to 90%). Non-adherence, extrapulmonary/disseminated disease and advanced immunosuppression in HIV co-infection were other risk factors noted. The weighted median cumulative incidence of acquired multi drug resistance calculated in 24 studies (assuming whole cohort as denominator, regardless of follow up DST) was 0.1% (5th to 95th percentile 0.07 to 3.2%). Conclusion Baseline drug resistance and HIV co-infection were significant risk factors for ADR. There was a trend of positive association with

  7. Arabidopsis TTR1 causes LRR-dependent lethal systemic necrosis, rather than systemic acquired resistance, to Tobacco ringspot virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Most Arabidopsis ecotypes display tolerance to the Tobacco ringspot virus (TRSV), but a subset of Arabidopsis ecotypes, including Estland (Est), develop lethal systemic necrosis (LSN), which differs from the localized hypersensitive responses (HRs) or systemic acquired resistance (SAR) characteristi...

  8. Long-term persistence of acquired resistance to 5-fluorouracil in the colon cancer cell line SW620

    SciTech Connect

    Tentes, I.K.; Schmidt, W.M.; Krupitza, G.; Steger, G.G.; Mikulits, W.; Kortsaris, A.; Mader, R.M.

    2010-11-15

    Treatment resistance to antineoplastic drugs represents a major clinical problem. Here, we investigated the long-term stability of acquired resistance to 5-fluorouracil (FU) in an in vitro colon cancer model, using four sub-clones characterised by increasing FU-resistance derived from the cell line SW620. The resistance phenotype was preserved after FU withdrawal for 15 weeks ({approx} 100 cell divisions) independent of the established level of drug resistance and of epigenetic silencing. Remarkably, resistant clones tolerated serum deprivation, adopted a CD133{sup +} CD44{sup -} phenotype, and further exhibited loss of membrane-bound E-cadherin together with predominant nuclear {beta}-catenin localisation. Thus, we provide evidence for a long-term memory of acquired drug resistance, driven by multiple cellular strategies (epithelial-mesenchymal transition and selective propagation of CD133{sup +} cells). These resistance phenomena, in turn, accentuate the malignant phenotype.

  9. NF-κB drives acquired resistance to a novel mutant-selective EGFR inhibitor.

    PubMed

    Galvani, Elena; Sun, Jing; Leon, Leticia G; Sciarrillo, Rocco; Narayan, Ravi S; Sjin, Robert Tjin Tham; Lee, Kwangho; Ohashi, Kadoaki; Heideman, Daniëlle A M; Alfieri, Roberta R; Heynen, Guus J; Bernards, René; Smit, Egbert F; Pao, William; Peters, Godefridus J; Giovannetti, Elisa

    2015-12-15

    The clinical efficacy of EGFR tyrosine kinase inhibitors (TKIs) in non-small cell lung cancer (NSCLC) harbouring activating EGFR mutations is limited by the emergence of acquired resistance, mostly ascribed to the secondary EGFR-T790M mutation. Selective EGFR-T790M inhibitors have been proposed as a new, extremely relevant therapeutic approach. Here, we demonstrate that the novel irreversible EGFR-TKI CNX-2006, a structural analog of CO-1686, currently tested in a phase-1/2 trial, is active against in vitro and in vivo NSCLC models expressing mutant EGFR, with minimal effect on the wild-type receptor. By integration of genetic and functional analyses in isogenic cell pairs we provide evidence of the crucial role played by NF-κB1 in driving CNX-2006 acquired resistance and show that NF-κB activation may replace the oncogenic EGFR signaling in NSCLC when effective and persistent inhibition of the target is achieved in the presence of the T790M mutation. In this context, we demonstrate that the sole, either genetic or pharmacologic, inhibition of NF-κB is sufficient to reduce the viability of cells that adapted to EGFR-TKIs. Overall, our findings support the rational inhibition of members of the NF-κB pathway as a promising therapeutic option for patients who progress after treatment with novel mutant-selective EGFR-TKIs.

  10. NF-κB drives acquired resistance to a novel mutant-selective EGFR inhibitor

    PubMed Central

    Galvani, Elena; Sun, Jing; Leon, Leticia G.; Sciarrillo, Rocco; Narayan, Ravi S.; Tjin Tham Sjin, Robert; Lee, Kwangho; Ohashi, Kadoaki; Heideman, Daniëlle A.M.; Alfieri, Roberta R.; Heynen, Guus J.; Bernards, René; Smit, Egbert F.; Pao, William; Peters, Godefridus J.; Giovannetti, Elisa

    2015-01-01

    The clinical efficacy of EGFR tyrosine kinase inhibitors (TKIs) in non-small cell lung cancer (NSCLC) harbouring activating EGFR mutations is limited by the emergence of acquired resistance, mostly ascribed to the secondary EGFR-T790M mutation. Selective EGFR-T790M inhibitors have been proposed as a new, extremely relevant therapeutic approach. Here, we demonstrate that the novel irreversible EGFR-TKI CNX-2006, a structural analog of CO-1686, currently tested in a phase-1/2 trial, is active against in vitro and in vivo NSCLC models expressing mutant EGFR, with minimal effect on the wild-type receptor. By integration of genetic and functional analyses in isogenic cell pairs we provide evidence of the crucial role played by NF-κB1 in driving CNX-2006 acquired resistance and show that NF-κB activation may replace the oncogenic EGFR signaling in NSCLC when effective and persistent inhibition of the target is achieved in the presence of the T790M mutation. In this context, we demonstrate that the sole, either genetic or pharmacologic, inhibition of NF-κB is sufficient to reduce the viability of cells that adapted to EGFR-TKIs. Overall, our findings support the rational inhibition of members of the NF-κB pathway as a promising therapeutic option for patients who progress after treatment with novel mutant-selective EGFR-TKIs. PMID:26015408

  11. Potential attenuation of p38 signaling by DDB2 as a factor in acquired TNF resistance.

    PubMed

    Sun, Chun-Ling; Chao, Chuck C-K

    2005-06-20

    Our previous study demonstrated that DDB2, a DNA repair protein, attenuates cell surface membrane-associated death signal induced by UV or FasAb; DDB2 is overexpressed in cisplatin-selected cells. However, the molecular mechanism underlying the protective role of DDB2 along the apoptotic pathway remains unknown. Our study identified the cross-resistance of the cisplatin-selected cells to tumor necrosis factor-alpha (TNF-alpha). Since knock-down of the DDB2 level rendered cells (HR18) sensitive to the treatment, the cell sensitivity to TNF-alpha appears inversely proportional to the cellular level of DDB2. Treatment of HeLa cells with TNF-alpha transiently induced activation of p38MAPK signal, but this induction was significantly reduced in the resistant cells. Overexpression of DDB2 attenuated the activation of p38 in cells. TNF-alpha-induced apoptotic signals, represented by caspase-8 and downstream substrate cleavage, were reduced in resistant cells compared to their sensitive counterparts. Inhibition of p38 signal by SB202190 clearly attenuated TNF-alpha-induced apoptotic signals. Moreover, overexpression of DDB2 in HR18 cells also attenuated TNF-alpha induced caspase activation. These results suggest that p38MAPK activation may be a key upstream signal of TNF-alpha-induced apoptosis and that attenuation of p38 signal by DDB2 overexpression may be responsible for acquired TNF-alpha resistance. PMID:15700318

  12. Effects of Sorafenib Dose on Acquired Reversible Resistance and Toxicity in Hepatocellular Carcinoma.

    PubMed

    Kuczynski, Elizabeth A; Lee, Christina R; Man, Shan; Chen, Eric; Kerbel, Robert S

    2015-06-15

    Acquired evasive resistance is a major limitation of hepatocellular carcinoma (HCC) treatment with the tyrosine kinase inhibitor (TKI) sorafenib. Recent findings suggest that resistance to sorafenib may have a reversible phenotype. In addition, loss of responsiveness has been proposed to be due to a gradual decrease in sorafenib plasma levels in patients. Here, the possible mechanisms underlying reversible sorafenib resistance were investigated using a Hep3B-hCG orthotopic human xenograft model of locally advanced HCC. Tissue and plasma sorafenib and metabolite levels, downstream antitumor targets, and toxicity were assessed during standard and dose-escalated sorafenib treatment. Drug levels were found to decline significantly over time in mice treated with 30 mg/kg sorafenib, coinciding with the onset of resistance but a greater magnitude of change was observed in tissues compared with plasma. Skin rash also correlated with drug levels and tended to decrease in severity over time. Drug level changes appeared to be partially tumor dependent involving induction of tumoral CYP3A4 metabolism, with host pretreatment alone unable to generate resistance. Escalation from 30 to 60 mg/kg sorafenib improved antitumor efficacy but worsened survival due to excessive body weight loss. Microvessel density was inhibited by sorafenib treatment but remained suppressed over time and dose increase. In conclusion, tumor CYP3A4 induction by sorafenib is a novel mechanism to account for variability in systemic drug levels; however, declining systemic sorafenib levels may only be a minor resistance mechanism. Escalating the dose may be an effective treatment strategy, provided toxicity can be controlled. PMID:25908587

  13. Combined treatment with silibinin and epidermal growth factor receptor tyrosine kinase inhibitors overcomes drug resistance caused by T790M mutation.

    PubMed

    Rho, Jin Kyung; Choi, Yun Jung; Jeon, Byung-Suk; Choi, Su Jin; Cheon, Gi Jeong; Woo, Sang-Keun; Kim, Hye-Ryoun; Kim, Cheol Hyeon; Choi, Chang-Min; Lee, Jae Cheol

    2010-12-01

    Although epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKI) produce an initially dramatic response in lung cancer patients harboring a mutation in the EGFR gene, development of acquired resistance is almost inevitable. A secondary mutation of threonine 790 (T790M) is associated with approximately half of the cases of acquired resistance. This study investigated whether the addition of silibinin to therapy with gefitinib or erlotinib could overcome T790M-mediated drug resistance considering that silibinin has various antitumor effects, including EGFR modulation. Silibinin selectively reduced the activity of the EGFR family (EGFR, ErbB2, and ErbB3) through the inhibition of receptor dimerization in lung cancer cells with EGFR mutations, but not in those harboring the wild type. In primary and acquired resistant cells with T790M, addition of silibinin enhanced the ability of EGFR-TKIs to downregulate EGFR signals and to inhibit cell growth. Similarly, the combination of silibinin and erlotinib effectively suppressed tumor growth in erlotinib resistance-bearing PC-9 xenografts. The results indicate that the addition of silibinin to EGFR-TKIs is a promising strategy to overcome T790M-mediated drug resistance.

  14. Antibiotic Resistance, Virulence, and Genetic Background of Community-Acquired Uropathogenic Escherichia coli from Algeria.

    PubMed

    Yahiaoui, Merzouk; Robin, Frédéric; Bakour, Rabah; Hamidi, Moufida; Bonnet, Richard; Messai, Yamina

    2015-10-01

    The aim of the study was to investigate antibiotic resistance mechanisms, virulence traits, and genetic background of 150 nonrepetitive community-acquired uropathogenic Escherichia coli (CA-UPEC) from Algeria. A rate of 46.7% of isolates was multidrug resistant. bla genes detected were blaTEM (96.8% of amoxicillin-resistant isolates), blaCTX-M-15 (4%), overexpressed blaAmpC (4%), blaSHV-2a, blaTEM-4, blaTEM-31, and blaTEM-35 (0.7%). All tetracycline-resistant isolates (51.3%) had tetA and/or tetB genes. Sulfonamides and trimethoprim resistance genes were sul2 (60.8%), sul1 (45.9%), sul3 (6.7%), dfrA14 (25.4%), dfrA1 (18.2%), dfrA12 (16.3%), and dfrA25 (5.4%). High-level fluoroquinolone resistance (22.7%) was mediated by mutations in gyrA (S83L-D87N) and parC (S80I-E84G/V or S80I) genes. qnrB5, qnrS1, and aac(6')-Ib-cr were rare (5.3%). Class 1 and/or class 2 integrons were detected (40.7%). Isolates belonged to phylogroups B2+D (50%), A+B1 (36%), and F+C+Clade I (13%). Most of D (72.2%) and 38.6% of B2 isolates were multidrug resistant; they belong to 14 different sequence types, including international successful ST131, ST73, and ST69, reported for the first time in the community in Algeria and new ST4494 and ST4529 described in this study. Besides multidrug resistance, B2 and D isolates possessed virulence factors of colonization, invasion, and long-term persistence. The study highlighted multidrug-resistant CA-UPEC with high virulence traits and an epidemic genetic background.

  15. Macrolide-resistant Mycoplasma pneumoniae in adolescents with community-acquired pneumonia

    PubMed Central

    2012-01-01

    Background Although the prevalence of macrolide-resistant Mycoplasma pneumoniae isolates in Japanese pediatric patients has increased rapidly, there have been no reports concerning macrolide-resistant M. pneumoniae infection in adolescents aged 16 to 19 years old. The purpose of this study was to clarify the prevalence and clinical characteristics of macrolide-resistant M. pneumoniae in adolescent patients with community-acquired pneumonia. Methods A total of 99 cases with M. pneumoniae pneumonia confirmed by polymerase chain reaction (PCR) and culture were analyzed. Forty-five cases were pediatric patients less than 16 years old, 26 cases were 16 to 19-year-old adolescent patients and 28 cases were adult patients. Primers for domain V of 23S rRNA were used and DNA sequences of the PCR products were compared with the sequence of an M. pneumoniae reference strain. Results Thirty of 45 pediatric patients (66%), 12 of 26 adolescent patients (46%) and seven of 28 adult patients (25%) with M. pneumoniae pneumonia were found to be infected with macrolide-resistant M. pneumoniae (MR patients). Although the prevalence of resistant strains was similar in pediatric patients between 2008 and 2011, an increase in the prevalence of resistant strains was observed in adolescent patients. Among 30 pediatric MR patients, 26 had an A-to-G transition at position 2063 (A2063G) and four had an A-to-G transition at position 2064 (A2064G). In 12 adolescent MR patients, 10 showed an A2063G transition and two showed an A2064G transition, and in seven adult MR patients, six showed an A2063G transition and one showed an A2064G transition. Conclusions The prevalence of macrolide-resistant M. pneumoniae is high among adolescent patients as well as pediatric patients less than 16-years old. To prevent outbreaks of M. pneumoniae infection, especially macrolide-resistant M. pneumoniae, in closed populations including among families, in schools and in university students, physicians should pay

  16. Acquired resistance to the 16-membered macrolides tylosin and tilmicosin by Mycoplasma bovis.

    PubMed

    Lerner, Uri; Amram, Eytan; Ayling, Roger D; Mikula, Inna; Gerchman, Irena; Harrus, Shimon; Teff, Dina; Yogev, David; Lysnyansky, Inna

    2014-01-31

    The molecular mechanism of acquired resistance to the 16-membered macrolides tylosin (Ty) and tilmicosin (Tm) was investigated in Mycoplasma bovis field isolates. Sequence analysis of domains II and V of the two 23S rRNA alleles and ribosomal proteins L4 and L22 was performed on 54 M. bovis isolates showing different minimal inhibitory concentrations (MIC). The presence of any one of the point mutations G748A, C752T, A2058G, A2059G or A2059C (Escherichia coli numbering) in one or both alleles of the 23S rRNAs was correlated with decreased susceptibility to Ty (8-1024 μg/ml) and to Tm (32 to >256 μg/ml) in 27/27 and 27/31 M. bovis isolates, respectively. Although a single mutation in domain II or V could be sufficient to cause decreased susceptibility to Ty, our data imply that a combination of mutations in two domains is necessary to achieve higher MICs (≥ 128 μg/ml). The influence of a combination of mutations in two domains II and V on enhancement of resistance to Tm was less clear. In addition, the amino acid (aa) substitution L22-Q90H was found in 24/32 representative M. bovis isolates with different MICs, but no correlation with decreased susceptibility to Ty or Tm was identified. Multiple aa substitutions were also identified in the L4 protein, including at positions 185-186 (positions 64 and 65 in E. coli) which are adjacent to the macrolide-binding site. This is the first description of the molecular mechanism of acquired resistance to the 16-membered macrolides in M. bovis. PMID:24393633

  17. Acquired resistance to the 16-membered macrolides tylosin and tilmicosin by Mycoplasma bovis.

    PubMed

    Lerner, Uri; Amram, Eytan; Ayling, Roger D; Mikula, Inna; Gerchman, Irena; Harrus, Shimon; Teff, Dina; Yogev, David; Lysnyansky, Inna

    2014-01-31

    The molecular mechanism of acquired resistance to the 16-membered macrolides tylosin (Ty) and tilmicosin (Tm) was investigated in Mycoplasma bovis field isolates. Sequence analysis of domains II and V of the two 23S rRNA alleles and ribosomal proteins L4 and L22 was performed on 54 M. bovis isolates showing different minimal inhibitory concentrations (MIC). The presence of any one of the point mutations G748A, C752T, A2058G, A2059G or A2059C (Escherichia coli numbering) in one or both alleles of the 23S rRNAs was correlated with decreased susceptibility to Ty (8-1024 μg/ml) and to Tm (32 to >256 μg/ml) in 27/27 and 27/31 M. bovis isolates, respectively. Although a single mutation in domain II or V could be sufficient to cause decreased susceptibility to Ty, our data imply that a combination of mutations in two domains is necessary to achieve higher MICs (≥ 128 μg/ml). The influence of a combination of mutations in two domains II and V on enhancement of resistance to Tm was less clear. In addition, the amino acid (aa) substitution L22-Q90H was found in 24/32 representative M. bovis isolates with different MICs, but no correlation with decreased susceptibility to Ty or Tm was identified. Multiple aa substitutions were also identified in the L4 protein, including at positions 185-186 (positions 64 and 65 in E. coli) which are adjacent to the macrolide-binding site. This is the first description of the molecular mechanism of acquired resistance to the 16-membered macrolides in M. bovis.

  18. Interconnection between flowering time control and activation of systemic acquired resistance

    PubMed Central

    Banday, Zeeshan Z.; Nandi, Ashis K.

    2015-01-01

    The ability to avoid or neutralize pathogens is inherent to all higher organisms including plants. Plants recognize pathogens through receptors, and mount resistance against the intruders, with the help of well-elaborated defense arsenal. In response to some localinfections, plants develop systemic acquired resistance (SAR), which provides heightened resistance during subsequent infections. Infected tissues generate mobile signaling molecules that travel to the systemic tissues, where they epigenetically modify expression o a set of genes to initiate the manifestation of SAR in distant tissues. Immune responses are largely regulated at transcriptional level. Flowering is a developmental transition that occurs as a result of the coordinated action of large numbers of transcription factors that respond to intrinsic signals and environmental conditions. The plant hormone salicylic acid (SA) which is required for SAR activation positively regulates flowering. Certain components of chromatin remodeling complexes that are recruited for suppression of precocious flowering are also involved in suppression of SAR in healthy plants. FLOWERING LOCUS D, a putative histone demethylase positively regulates SAR manifestation and flowering transition in Arabidopsis. Similarly, incorporation of histone variant H2A.Z in nucleosomes mediated by PHOTOPERIOD-INDEPENDENT EARLY FLOWERING 1, an ortholog of yeast chromatin remodeling complex SWR1, concomitantly influences SAR and flowering time. SUMO conjugation and deconjugation mechanisms also similarly affect SAR and flowering in an SA-dependent manner. The evidences suggest a common underlying regulatory mechanism for activation of SAR and flowering in plants. PMID:25852723

  19. Interconnection between flowering time control and activation of systemic acquired resistance.

    PubMed

    Banday, Zeeshan Z; Nandi, Ashis K

    2015-01-01

    The ability to avoid or neutralize pathogens is inherent to all higher organisms including plants. Plants recognize pathogens through receptors, and mount resistance against the intruders, with the help of well-elaborated defense arsenal. In response to some localinfections, plants develop systemic acquired resistance (SAR), which provides heightened resistance during subsequent infections. Infected tissues generate mobile signaling molecules that travel to the systemic tissues, where they epigenetically modify expression o a set of genes to initiate the manifestation of SAR in distant tissues. Immune responses are largely regulated at transcriptional level. Flowering is a developmental transition that occurs as a result of the coordinated action of large numbers of transcription factors that respond to intrinsic signals and environmental conditions. The plant hormone salicylic acid (SA) which is required for SAR activation positively regulates flowering. Certain components of chromatin remodeling complexes that are recruited for suppression of precocious flowering are also involved in suppression of SAR in healthy plants. FLOWERING LOCUS D, a putative histone demethylase positively regulates SAR manifestation and flowering transition in Arabidopsis. Similarly, incorporation of histone variant H2A.Z in nucleosomes mediated by PHOTOPERIOD-INDEPENDENT EARLY FLOWERING 1, an ortholog of yeast chromatin remodeling complex SWR1, concomitantly influences SAR and flowering time. SUMO conjugation and deconjugation mechanisms also similarly affect SAR and flowering in an SA-dependent manner. The evidences suggest a common underlying regulatory mechanism for activation of SAR and flowering in plants.

  20. Acquired resistance and clonal evolution in melanoma during BRAF inhibitor therapy

    PubMed Central

    Kong, Xiangju; Hong, Aayoung; Koya, Richard C.; Moriceau, Gatien; Chodon, Thinle; Guo, Rongqing; Johnson, Douglas B.; Dahlman, Kimberly B.; Kelley, Mark C.; Kefford, Richard F.; Chmielowski, Bartosz; Glaspy, John A.; Sosman, Jeffrey A.; van Baren, Nicolas; Long, Georgina V.; Ribas, Antoni; Lo, Roger S.

    2013-01-01

    BRAF inhibitors elicit rapid anti-tumor responses in the majority of patients with V600BRAF mutant melanoma, but acquired drug resistance is almost universal. We sought to identify the core resistance pathways and the extent of tumor heterogeneity during disease progression. We show that MAPK reactivation mechanisms were detected among 70% of disease-progressive tissues, with RAS mutations, mutant BRAF amplification and alternative splicing being most common. We also detected PI3K-PTEN-AKT-upregulating genetic alterations among 22% of progressive melanomas. Distinct molecular lesions, in both core drug escape pathways, were commonly detected concurrently in the same tumor or among multiple tumors from the same patient. Beyond harboring extensively heterogeneous resistance mechanisms, melanoma re-growth emerging from BRAF inhibitor selection displayed branched evolution marked by altered mutational spectra/signatures and increased fitness. Thus, melanoma genomic heterogeneity contributes significantly to BRAF inhibitor treatment failure, implying upfront, co-targeting of two core pathways as an essential strategy for durable responses. PMID:24265155

  1. The mechanism of acquired resistance to irreversible EGFR tyrosine kinase inhibitor-afatinib in lung adenocarcinoma patients

    PubMed Central

    Wu, Shang-Gin; Liu, Yi-Nan; Tsai, Meng-Feng; Chang, Yih-Leong; Yu, Chong-Jen; Yang, Pan-Chyr; Yang, James Chih-Hsin; Wen, Yueh-Feng; Shih, Jin-Yuan

    2016-01-01

    Introduction Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) are associated with favorable response in EGFR mutant lung cancer. Acquired resistance to reversible EGFR TKIs remains a significant barrier, and acquired EGFR T790M-mutation is the major mechanism. Second-generation irreversible EGFR TKI, afatinib, had also been approved for treating EGFR mutant lung cancer patients, but the mechanism of acquired resistance to afatinib has not been well studied. Results Forty-two patients had tissue specimens taken after acquiring resistance to afatinib. The sensitizing EGFR mutation were all consistent between pre- and post-afatinib tissues. Twenty patients (47.6%) had acquired T790M mutation. T790M rate was not different between first-generation EGFR TKI-naïve patients (50%) and first-generation EGFR TKI-treated patients (46.4%) (p = 0.827). No clinical characteristics or EGFR mutation types were associated with the development of acquired T790M. No other second-site EGFR mutations were detected. There were no small cell or squamous cell lung cancer transformation. Other genetic mutations were not identified in PIK3CA, BRAF, HER2, KRAS, NRAS, MEK1, AKT2, LKB1 and JAK2. Methods Afatinib-prescription record of our department of pharmacy from January 2007 and December 2014 was retrieved. We investigated patients with tissue specimens available after acquiring resistance to afatinib. Enrolled patients should have partial response or durable stable disease of treatment response to afatinib. Various mechanisms of acquired resistance to first-generation EGFR TKIs were evaluated. Histology and cytology were reviewed. EGFR, PIK3CA, BRAF, HER2, KRAS, NRAS, MEK1, AKT2, LKB1 and JAK2 genetic alterations were evaluated by sequencing. Statistical analysis was performed using Chi-square test and Kaplan-Meier method. Conclusions T790M was detected in half of the lung adenocarcinoma after acquiring resistance to afatinib. T790M is still the major acquired

  2. Acquisition of cancer stem cell-like properties in non-small cell lung cancer with acquired resistance to afatinib

    PubMed Central

    Hashida, Shinsuke; Yamamoto, Hiromasa; Shien, Kazuhiko; Miyoshi, Yuichiro; Ohtsuka, Tomoaki; Suzawa, Ken; Watanabe, Mototsugu; Maki, Yuho; Soh, Junichi; Asano, Hiroaki; Tsukuda, Kazunori; Miyoshi, Shinichiro; Toyooka, Shinichi

    2015-01-01

    Afatinib is an irreversible epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor (TKI) that is known to be effective against the EGFR T790M variant, which accounts for half of the mechanisms of acquired resistance to reversible EGFR-TKIs. However, acquired resistance to afatinib was also observed in clinical use. Thus, elucidating and overcoming the mechanisms of resistance are important issues in the treatment of non-small cell lung cancer. In this study, we established various afatinib-resistant cell lines and investigated the resistance mechanisms. EGFR T790M mutations were not detected using direct sequencing in established resistant cells. Several afatinib-resistant cell lines displayed MET amplification, and these cells were sensitive to the combination of afatinib plus crizotinib. As a further investigation, a cell line that acquired resistance to afatinib plus crizotinib, HCC827-ACR, was established from one of the MET amplified-cell lines. Several afatinib-resistant cell lines including HCC827-ACR displayed epithelial-to-mesenchymal transition (EMT) features and epigenetic silencing of miR-200c, which is a suppresser of EMT. In addition, these cell lines also exhibited overexpression of ALDH1A1 and ABCB1, which are putative stem cell markers, and resistance to docetaxel. In conclusion, we established afatinib-resistant cells and found that MET amplification, EMT, and stem cell-like features are observed in cells with acquired resistance to EGFR-TKIs. This finding may provide clues to overcoming resistance to EGFR-TKIs. PMID:26202045

  3. Impaired acquired resistance of mice to Klebsiella pneumoniae infection induced by acute NO/sub 2/ exposure

    SciTech Connect

    Bouley, G.; Azoulay-Dupuis, E.; Gaudebout, C.

    1985-12-01

    The natural resistance of nonimmunized C57B1/6 mice to an intraperitoneal Klebsiella pneumoniae challenge was not significantly affected by prior continuous exposure to 20 ppm NO/sub 2/ for 4 days. In contrast, the acquired resistance of mice immunized just before and infected just after NO/sub 2/ exposure was seriously impaired. This could not be explained by the loss of appetite (about 30%) observed in NO/sub 2/ treated mice, for neither the natural nor acquired resistance of control air exposure mice given approximately 70% ad libitum food and water were significantly modified.

  4. Effectiveness of various hospital-based solutions against community- acquired methicillin-resistant Staphylococcus aureus.

    PubMed

    Perona, Paul J; Johnson, Aaron J; Perona, John P; Issa, Kimona; Kapadia, Bhaveen H; Bonutti, Peter M; Mont, Michael A

    2013-01-01

    Periprosthetic infections with methicillin-resistant Staphylococcus aureus (MRSA) can be particularly burdensome and difficult to eradicate. One of the measures that infection control officers have emphasized in our hospitals has been the use of various hand sanitizers throughout the hospital. Our objective was to determine the level of growth inhibition of common hand sanitizers and surgical scrub solutions that are used to prevent the spread of community-acquired strains of MRSA. Various hospital and surgical agents (n = 13) were applied to community-acquired MRSA bacteria that had been cultured on agar plates. These different commercially available solutions were incubated for 48 h, and the plates were assessed to determine the level of growth inhibition (0, 25, 75, or 100%). The negative control was a test in which no agent was added to the MRSA culture, while a positive control tested 100% alcohol. Eight of the solutions tested had 100% growth inhibition, four solutions had partial growth inhibition effects, and one solution did not inhibit MRSA. Of the solutions with alcohol, the 62% solution did not kill MRSA, while the 80% solution only inhibited MRSA. Both the 95 and 100% alcohol solutions had 100% growth inhibition. Of the two surgical scrub solutions, only the one with iodine had 100% growth inhibition, whereas the solution with chloroxylenol (PCMX 3%) had only partial growth inhibition. This study suggests that the solutions with high levels of alcohol, chlorhexidine, or iodine appear to better kill MRSA and might best be used to prevent the spread of community-acquired MRSA in both the hospital and the surgical environment. PMID:24266441

  5. Discovery of functional genes for systemic acquired resistance in Arabidopsis thaliana through integrated data mining.

    PubMed

    Pan, Youlian; Pylatuik, Jeffrey D; Ouyang, Junjun; Famili, A Fazel; Fobert, Pierre R

    2004-12-01

    Various data mining techniques combined with sequence motif information in the promoter region of genes were applied to discover functional genes that are involved in the defense mechanism of systemic acquired resistance (SAR) in Arabidopsis thaliana. A series of K-Means clustering with difference-in-shape as distance measure was initially applied. A stability measure was used to validate this clustering process. A decision tree algorithm with the discover-and-mask technique was used to identify a group of most informative genes. Appearance and abundance of various transcription factor binding sites in the promoter region of the genes were studied. Through the combination of these techniques, we were able to identify 24 candidate genes involved in the SAR defense mechanism. The candidate genes fell into 2 highly resolved categories, each category showing significantly unique profiles of regulatory elements in their promoter regions. This study demonstrates the strength of such integration methods and suggests a broader application of this approach.

  6. A possible mechanism of acquired acid resistance of human dental enamel by laser irradiation.

    PubMed

    Oho, T; Morioka, T

    1990-01-01

    A possible mechanism of acquired acid resistance of lased enamel was proposed on the basis of the investigations of optical properties, compositional and structural changes and permeability of lased and unlased human dental enamel. Lased enamel showed a high positive birefringence, suggesting the formation of 'microspaces' in enamel. No new products were found, though a decrease of lattice strain and a slight a-axis contraction were recognized in lased enamel compared with unlased enamel. The contents of water, carbonate and organic substances were reduced in lased enamel. Gradual changes of birefringence were observed in lased enamel during treatment with acid solutions, and this change was attributed to mineralization of the microspaces. The ions released by an acid decalcification would be trapped in the microspaces in lased enamel, whereas such ions diffuse to the surrounding solution in unlased enamel.

  7. Effect of chemical systemic acquired resistance elicitors on avenanthramide biosynthesis in oat (Avena sativa).

    PubMed

    Wise, Mitchell L

    2011-07-13

    Oats produce a group of phenolic antioxidants termed avenanthramides. These metabolites are, among food crops, unique to oats and have shown, in experimental systems, certain desirable nutritional characteristics such as inhibiting atherosclerotic plaque formation and reducing inflammation. Avenanthramides occur in both the leaves and grain of oat. In the leaves they are expressed as phytoalexins in response to crown rust (Puccina coronata) infection. The experiments reported here demonstrate that avenanthramide levels in vegetative tissue can be enhanced by treatment with benzothiadiazole (BTH), an agrochemical formulated to elicit systemic acquired resistance (SAR). The response to BTH was dramatically stronger than those produced with salicylic acid treatment. The roots of BTH treated plants also showed a smaller but distinct increase in avenanthramides. The dynamics of the root avenanthramide increase was substantially slower than that observed in the leaves, suggesting that avenanthramides might be transported from the leaves.

  8. Cardiac tamponade complicating purulent pericarditis due to community acquired methicilin resistant Staphylococcus aureus (CA-MRSA).

    PubMed

    Bagavathy, Kavitha; Raju, Shine K; Joseph, Ranjit; Kumar, Anupam

    2014-03-01

    Community acquired methicillin resistant Staphylococcus aureus(CA-MRSA) is a global pathogen capable of causing life-threatening infections with increasing prevalence since the 1990s. Purulentpericarditis, characterized by accumulation of purulent fluid in the pericardial space was historically a disease of the pediatric and early adult population, but through the years the median age of diagnosis has increased from 21 to 49. Mortality rates are as high as 40% even in the treated population. We report a case of purulent pericarditis due to CA-MRSA that was complicated by cardiac tamponade. Early diagnosis and intervention proved to be life-saving. A brief review of the literature and current management options are discussed.

  9. Fulminant necrotising fasciitis by community-acquired methicillin-resistant Staphylococcus aureus.

    PubMed

    Non, Lemuel; Kosmin, Aaron

    2015-03-30

    Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) is a rare cause of necrotising fasciitis (NF), and is usually not fulminant as in group A Streptococcus (GAS), the archetypal aetiology. We report an unusually fulminant case of NF by CA-MRSA in an immunocompetent patient. A 52-year-old man presented to the emergency department with 1 week of progressive left thigh pain and swelling. The patient had ecchymoses, bullae and hypoesthesia of the involved skin, and CT scan revealed extensive fascial oedema. He was immediately started on broad spectrum antibiotics. Within 12 h of presentation, he underwent surgical debridement. Despite aggressive supportive care, the patient died less than 24 h after presentation. MRSA, with an antibiogram suggestive of a community-acquired strain, was recovered from intraoperative specimens and admission blood cultures. This case underscores that CA-MRSA, while rarely reported, can cause a fulminant presentation of NF similar to GAS in immunocompetent patients.

  10. Community-Acquired Methicillin-Resistant Pyogenic Liver Abscess: A Case Report.

    PubMed

    Cherian, Joel; Singh, Rahul; Varma, Muralidhar; Vidyasagar, Sudha; Mukhopadhyay, Chiranjay

    2016-01-01

    Pyogenic liver abscesses are rare with an incidence of 0.5% to 0.8% and are mostly due to hepatobiliary causes (40% to 60%). Most are polymicrobial with less than 10% being caused by Staphylococcus aureus. Of these, few are caused by methicillin-resistant Staphylococcus aureus (MRSA) and fewer still by a community-acquired strain. Here we present a case study of a patient with a community-acquired MRSA liver abscess. The patient presented with fever since 1 month and tender hepatomegaly. Blood tests revealed elevated levels of alkaline phosphatase, C-reactive protein, erythrocyte sedimentation rate, and neutrophilic leukocytosis. Blood cultures were sterile. Ultrasound of the abdomen showed multiple abscesses, from which pus was drained and MRSA isolated. Computed tomography of the abdomen did not show any source of infection, and an amebic serology was negative. The patient was started on vancomycin for 2 weeks, following which he became afebrile and was discharged on oral linezolid for 4 more weeks. Normally a liver abscess is treated empirically with ceftriaxone for pyogenic liver abscess and metronidazole for amebic liver abscess. However, if the patient has risk factors for a Staphylococcal infection, it is imperative that antibiotics covering gram-positive organisms be added while waiting for culture reports. PMID:27540556

  11. Caterpillar saliva interferes with induced Arabidopsis thaliana defence responses via the systemic acquired resistance pathway

    PubMed Central

    Weech, Marie-Hélène; Chapleau, Mélanie; Pan, Li; Ide, Christine; Bede, Jacqueline C.

    2008-01-01

    Arabidopsis thaliana (L.) Heynh. genotypes limited in their ability to mount either octadecanoid-dependent induced resistance (IR–) or systemic acquired resistance (SAR–) were used to characterize the roles of these pathways in plant–herbivore interactions. Molecular and biochemical markers of IR were analysed in plants subject to herbivory by caterpillars of the beet armyworm, Spodoptera exigua Hübner, which had either intact or impaired salivary secretions since salivary enzymes, such as glucose oxidase, have been implicated in the ability of caterpillars to circumvent induced plant defences. Transcript expression of genes encoding laccase-like multicopper oxidase [AtLMCO4 (polyphenol oxidase)] and defensin (AtPDF1.2) showed salivary-specific patterns which were disrupted in the SAR– mutant plants. The activity of octadecanoid-associated anti-nutritive proteins, such as LMCO and trypsin inhibitor, showed similar patterns. Gene and protein changes parallel plant hormone levels where elevated jasmonic acid was observed in wild-type plants fed upon by caterpillars with impaired salivary secretions compared with plants subject to herbivory by normal caterpillars. This salivary-specific difference in jasmonic acid levels was alleviated in SAR– mutants. These results support the model that caterpillar saliva interferes with jasmonate-dependent plant defences by activating the SAR pathway. PMID:18487634

  12. Acquired Resistance to Clinical Cancer Therapy: A Twist in Physiological Signaling.

    PubMed

    Wicki, Andreas; Mandalà, Mario; Massi, Daniela; Taverna, Daniela; Tang, Huifang; Hemmings, Brian A; Xue, Gongda

    2016-07-01

    Although modern therapeutic strategies have brought significant progress to cancer care in the last 30 years, drug resistance to targeted monotherapies has emerged as a major challenge. Aberrant regulation of multiple physiological signaling pathways indispensable for developmental and metabolic homeostasis, such as hyperactivation of pro-survival signaling axes, loss of suppressive regulations, and impaired functionalities of the immune system, have been extensively investigated aiming to understand the diversity of molecular mechanisms that underlie cancer development and progression. In this review, we intend to discuss the molecular mechanisms of how conventional physiological signal transduction confers to acquired drug resistance in cancer patients. We will particularly focus on protooncogenic receptor kinase inhibition-elicited tumor cell adaptation through two major core downstream signaling cascades, the PI3K/Akt and MAPK pathways. These pathways are crucial for cell growth and differentiation and are frequently hyperactivated during tumorigenesis. In addition, we also emphasize the emerging roles of the deregulated host immune system that may actively promote cancer progression and attenuate immunosurveillance in cancer therapies. Understanding these mechanisms may help to develop more effective therapeutic strategies that are able to keep the tumor in check and even possibly turn cancer into a chronic disease.

  13. Persistence and Fitness of Multidrug-Resistant Human Immunodeficiency Virus Type 1 Acquired in Primary Infection

    PubMed Central

    Brenner, Bluma G.; Routy, Jean-Pierre; Petrella, Marco; Moisi, Daniela; Oliveira, Maureen; Detorio, Mervi; Spira, Bonnie; Essabag, Vidal; Conway, Brian; Lalonde, Richard; Sekaly, Rafick-Pierre; Wainberg, Mark A.

    2002-01-01

    This study examines the persistence and fitness of multidrug-resistant (MDR) viruses acquired during primary human immunodeficiency virus infection (PHI). In four individuals, MDR infections persisted over the entire study period, ranging from 36 weeks to 5 years, in the absence of antiretroviral therapy. In stark contrast, identified source partners in two cases showed expected outgrowth of wild-type (WT) virus within 12 weeks of treatment interruption. In the first PHI case, triple-class MDR resulted in low plasma viremia (1.6 to 3 log copies/ml) over time compared with mean values obtained for an untreated PHI group harboring WT infections (4.1 to 4.3 log copies/ml). Increasing viremia in PHI patient 1 at week 52 was associated with the de novo emergence of a protease inhibitor-resistant variant through a recombination event involving the original MDR virus. MDR infections in two other untreated PHI patients yielded viremia levels typical of the untreated WT group. A fourth patient's MDR infection yielded low viremia (<50 to 500 copies/ml) for 5 years despite his having phenotypic resistance to all antiretroviral drugs in his treatment regimen. In two of these PHI cases, a rebound to higher levels of plasma viremia only occurred when the M184V mutation in reverse transcriptase could no longer be detected and, in a third case, nondetection of M184V was associated with an inability to isolate virus. To further evaluate the fitness of MDR variants acquired in PHI, MDR and corresponding WT viruses were isolated from index and source partners, respectively. Although MDR viral infectivity (50% tissue culture infective dose) was comparable to that observed for WT viruses, MDR infections in each case demonstrated 2-fold and 13- to 23-fold reductions in p24 antigen and reverse transcriptase enzymatic activity, respectively. In dual-infection competition assays, MDR viruses consistently demonstrated a marked replicative disadvantage compared with WT virus. These results

  14. Nasal colonization in children with community acquired methicillin-resistant Staphylococcus aureus

    PubMed Central

    Davoodabadi, Fazlollah; Mobasherizadeh, Sina; Mostafavizadeh, Kamyar; Shojaei, Hasan; Havaei, Seyed Asghar; Koushki, Ali Mehrabi; Moghadasizadeh, Zahra; Meidani, Mohsen; Shirani, Kiana

    2016-01-01

    Background: Methicillin-resistant Staphylococcus aureus (MRSA) is a frequent cause of infections. The changing epidemiology of MRSA became evident in the 1990s when CA-MRSA cases were first reported. Nasal carriage of CA-MRSA is associated with an increased risk for development of infections in various populations. Materials and Methods: Anterior nares culture for the presence of methicillin-susceptible Staphylococcus aureus (MSSA) and MRSA was taken from 345 children attending kindergartens, who didn’t have any known risk factor for MRSA colonization. Also, children demographic variables were recorded. Identification of SA and community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) with standard microbiological test was performed. Finally, the susceptibility of isolated to various antibiotics determined. The data were analyzed with Whonet 5.6 software. Results: Of 345 children, 20 children (5.8%) were colonized with CA-MRSA, 86 children (24.9%) with MSSA and 239 cases (69.3%) didn’t have SA colonization. The highest rate of MSSA and MRSA colonization was obtained at the age of 6 years. The frequency distribution of SA (MSSA and MRSA) colonization prevalence didn’t have any significant differences based on age, gender and the admission time (P > 0.05); but it was significantly different in the urban areas (P < 0.001). The lowest resistance rate of CA-MRSA isolates, with a frequency of 10%, was detected with gentamicin, rifampin, and trimethoprim-sulfamethoxazole. Conclusions: In summary, CA-MRSA colonization was observed in child care centers remarkably. Therefore, by facing various infections due to SA especially in areas of low socio-economic status, it must be considered. Based on antibiogram test, empirical treatment with rifampin, gentamicin and ciprofloxacin is recommended during CA-MRSA infections. PMID:27274501

  15. Systemic Acquired Resistance in Moss: Further Evidence for Conserved Defense Mechanisms in Plants

    PubMed Central

    Winter, Peter S.; Bowman, Collin E.; Villani, Philip J.; Dolan, Thomas E.; Hauck, Nathanael R.

    2014-01-01

    Vascular plants possess multiple mechanisms for defending themselves against pathogens. One well-characterized defense mechanism is systemic acquired resistance (SAR). In SAR, a plant detects the presence of a pathogen and transmits a signal throughout the plant, inducing changes in the expression of various pathogenesis-related (PR) genes. Once SAR is established, the plant is capable of mounting rapid responses to subsequent pathogen attacks. SAR has been characterized in numerous angiosperm and gymnosperm species; however, despite several pieces of evidence suggesting SAR may also exist in non-vascular plants6–8, its presence in non-vascular plants has not been conclusively demonstrated, in part due to the lack of an appropriate culture system. Here, we describe and use a novel culture system to demonstrate that the moss species Amblystegium serpens does initiate a SAR-like reaction upon inoculation with Pythium irregulare, a common soil-borne oomycete. Infection of A. serpens gametophores by P. irregulare is characterized by localized cytoplasmic shrinkage within 34 h and chlorosis and necrosis within 7 d of inoculation. Within 24 h of a primary inoculation (induction), moss gametophores grown in culture became highly resistant to infection following subsequent inoculation (challenge) by the same pathogen. This increased resistance was a response to the pathogen itself and not to physical wounding. Treatment with β-1,3 glucan, a structural component of oomycete cell walls, was equally effective at triggering SAR. Our results demonstrate, for the first time, that this important defense mechanism exists in a non-vascular plant, and, together with previous studies, suggest that SAR arose prior to the divergence of vascular and non-vascular plants. In addition, this novel moss – pathogen culture system will be valuable for future characterization of the mechanism of SAR in moss, which is necessary for a better understanding of the evolutionary history of SAR

  16. Comparative Proteomics Analysis of Phloem Exudates Collected during the Induction of Systemic Acquired Resistance1[OPEN

    PubMed Central

    Wilson, Daniel C.; Dey, Sanjukta; Hauck, Stefanie M.; Vlot, A. Corina; Cameron, Robin K.

    2016-01-01

    Systemic acquired resistance (SAR) is a plant defense response that provides long-lasting, broad-spectrum pathogen resistance to uninfected systemic leaves following an initial localized infection. In Arabidopsis (Arabidopsis thaliana), local infection with virulent or avirulent strains of Pseudomonas syringae pv tomato generates long-distance SAR signals that travel from locally infected to distant leaves through the phloem to establish SAR. In this study, a proteomics approach was used to identify proteins that accumulate in phloem exudates in response to the induction of SAR. To accomplish this, phloem exudates collected from mock-inoculated or SAR-induced leaves of wild-type Columbia-0 plants were subjected to label-free quantitative liquid chromatography-tandem mass spectrometry proteomics. Comparing mock- and SAR-induced phloem exudate proteomes, 16 proteins were enriched in phloem exudates collected from SAR-induced plants, while 46 proteins were suppressed. SAR-related proteins THIOREDOXIN h3, ACYL-COENZYME A-BINDING PROTEIN6, and PATHOGENESIS-RELATED1 were enriched in phloem exudates of SAR-induced plants, demonstrating the strength of this approach and suggesting a role for these proteins in the phloem during SAR. To identify novel components of SAR, transfer DNA mutants of differentially abundant phloem proteins were assayed for SAR competence. This analysis identified a number of new proteins (m-type thioredoxins, major latex protein-like protein, ULTRAVIOLET-B RESISTANCE8 photoreceptor) that contribute to the SAR response. The Arabidopsis SAR phloem proteome is a valuable resource for understanding SAR long-distance signaling and the dynamic nature of the phloem during plant-pathogen interactions. PMID:27208255

  17. Origin and Evolution of European Community-Acquired Methicillin-Resistant Staphylococcus aureus

    PubMed Central

    Wirth, Thierry; Andersen, Paal S.; Skov, Robert L.; De Grassi, Anna; Simões, Patricia Martins; Tristan, Anne; Petersen, Andreas; Aziz, Maliha; Kiil, Kristoffer; Cirković, Ivana; Udo, Edet E.; del Campo, Rosa; Vuopio-Varkila, Jaana; Ahmad, Norazah; Tokajian, Sima; Peters, Georg; Schaumburg, Frieder; Olsson-Liljequist, Barbro; Givskov, Michael; Driebe, Elizabeth E.; Vigh, Henrik E.; Shittu, Adebayo; Ramdani-Bougessa, Nadjia; Rasigade, Jean-Philippe; Price, Lance B.; Vandenesch, Francois; Larsen, Anders R.; Laurent, Frederic

    2014-01-01

    ABSTRACT Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) was recognized in Europe and worldwide in the late 1990s. Within a decade, several genetically and geographically distinct CA-MRSA lineages carrying the small SCCmec type IV and V genetic elements and the Panton-Valentine leukocidin (PVL) emerged around the world. In Europe, the predominant CA-MRSA strain belongs to clonal complex 80 (CC80) and is resistant to kanamycin/amikacin and fusidic acid. CC80 was first reported in 1993 but was relatively rare until the late 1990s. It has since been identified throughout North Africa, the Middle East, and Europe, with recent sporadic reports in sub-Saharan Africa. While strongly associated with skin and soft tissue infections, it is rarely found among asymptomatic carriers. Methicillin-sensitive S. aureus (MSSA) CC80 strains are extremely rare except in sub-Saharan Africa. In the current study, we applied whole-genome sequencing to a global collection of both MSSA and MRSA CC80 isolates. Phylogenetic analyses strongly suggest that the European epidemic CA-MRSA lineage is derived from a PVL-positive MSSA ancestor from sub-Saharan Africa. Moreover, the tree topology suggests a single acquisition of both the SCCmec element and a plasmid encoding the fusidic acid resistance determinant. Four canonical SNPs distinguish the derived CA-MRSA lineage and include a nonsynonymous mutation in accessory gene regulator C (agrC). These changes were associated with a star-like expansion into Europe, the Middle East, and North Africa in the early 1990s, including multiple cases of cross-continent imports likely driven by human migrations. PMID:25161186

  18. Disulfiram targets cancer stem-like cells and reverses resistance and cross-resistance in acquired paclitaxel-resistant triple-negative breast cancer cells

    PubMed Central

    Liu, P; Kumar, I S; Brown, S; Kannappan, V; Tawari, P E; Tang, J Z; Jiang, W; Armesilla, A L; Darling, J L; Wang, W

    2013-01-01

    Background: Triple-negative breast cancer (TNBC) has significantly worse prognosis. Acquired chemoresistance remains the major cause of therapeutic failure of TNBC. In clinic, the relapsed TNBC is commonly pan-resistant to various drugs with completely different resistant mechanisms. Investigation of the mechanisms and development of new drugs to target pan-chemoresistance will potentially improve the therapeutic outcomes of TNBC patients. Methods: In this study, 1-(4,5-Dimethylthiazol-2-yl)-3,5-diphenylformazan (MTT), combination index (CI)–isobologram, western blot, ALDEFLUOR analysis, clonogenic assay and immunocytochemistry were used. Results: The chemoresistant MDA-MB-231PAC10 cells are highly cross-resistant to paclitaxel (PAC), cisplatin (CDDP), docetaxel and doxorubicin. The MDA-MB-231PAC10 cells are quiescent with significantly longer doubling time (64.9 vs 31.7 h). This may be caused by high expression of p21Waf1. The MDA-MB-231PAC10 cells express high aldehyde dehydrogenase (ALDH) activity and a panel of embryonic stem cell-related proteins, for example, Oct4, Sox2, Nanog and nuclealisation of HIF2α and NF-κBp65. We have previously reported that disulfiram (DS), an antialcoholism drug, targets cancer stem cells (CSCs) and enhances cytotoxicity of anticancer drugs. Disulfiram abolished CSC characters and completely reversed PAC and CDDP resistance in MDA-MB-231PAC10 cells. Conclusion: Cancer stem cells may be responsible for acquired pan-chemoresistance. As a drug used in clinic, DS may be repurposed as a CSC inhibitor to reverse the acquired pan-chemoresistance. PMID:24008666

  19. Evidence for the role of microRNA 374b in acquired cisplatin resistance in pancreatic cancer cells

    PubMed Central

    Schreiber, R; Mezencev, R; Matyunina, L V; McDonald, J F

    2016-01-01

    Recent evidence has implicated microRNAs (miRNAs) as potentially significant players in the acquisition of cancer-drug resistance in pancreatic and other cancers. To evaluate the potential contribution of miRNAs in acquired resistance to cisplatin in pancreatic cancer, we compared levels of more than 2000 human miRNAs in a cisplatin-resistant cell line (BxPC3-R) derived from parental (BxPC3) cells by step-wise exposure to increasing concentrations of the drug over more than 20 passages. The acquired drug resistance was accompanied by significant changes in the expression of 57 miRNAs, of which 23 were downregulated and 34 were upregulated. Employing a hidden Markov model (HMM) algorithm, we identified downregulation of miR-374b as likely being directly involved in acquisition of the drug-resistant phenotype. Consistent with this prediction, ectopic overexpression of miR-374b in the resistant BxPC3-R cells restored cisplatin sensitivity to levels approaching those displayed by the BxPC3 parental cells. The results are consistent with a growing body of evidence implicating miRNAs in acquired cancer-drug resistance and with the potential therapeutic value of these small regulatory RNAs in blocking and/or reversing the process. PMID:27229158

  20. Increased interleukin-6 expression is associated with poor prognosis and acquired cisplatin resistance in head and neck squamous cell carcinoma

    PubMed Central

    GAO, JIAN; ZHAO, SEN; HALSTENSEN, TROND S.

    2016-01-01

    Increased expression of interleukin 6 (IL-6) is associated with poor prognosis and chemoresistance in many different carcinomas, but its role in head and neck squamous cell carcinoma (HNSCC) is still unsettled. Analyzing tumorous mRNA expression data from 399 HNSCC patients revealed that high IL-6 expression predicted poor prognosis. Similar tendency was observed in platinum treated patients, suggesting an IL-6 associated cisplatin resistance. IL-6 increase was also found in two in-house acquired cisplatin-resistant HNSCC cell lines (both basaloid and conventional squamous cell carcinoma) by using microarray analysis. However, although the in-house acquired cisplatin-resistant cell lines had higher basal and markedly increased cisplatin-induced IL-6 expression, IL-6 did not mediate the cisplatin resistance as neither exogenous IL-6 nor IL-6R/gp130 inhibitors affected cisplatin sensitivity. Moreover, the IL-6/STAT3 pathway was impaired in the resistant cell lines, partly due to decreased IL-6R expression. Thus, high IL-6 expression correlated to poor prognosis and acquired cisplatin resistance, but it did not mediate cisplatin resistance in the HNSCC cell lines. PMID:27108527

  1. Evidence for the role of microRNA 374b in acquired cisplatin resistance in pancreatic cancer cells.

    PubMed

    Schreiber, R; Mezencev, R; Matyunina, L V; McDonald, J F

    2016-08-01

    Recent evidence has implicated microRNAs (miRNAs) as potentially significant players in the acquisition of cancer-drug resistance in pancreatic and other cancers. To evaluate the potential contribution of miRNAs in acquired resistance to cisplatin in pancreatic cancer, we compared levels of more than 2000 human miRNAs in a cisplatin-resistant cell line (BxPC3-R) derived from parental (BxPC3) cells by step-wise exposure to increasing concentrations of the drug over more than 20 passages. The acquired drug resistance was accompanied by significant changes in the expression of 57 miRNAs, of which 23 were downregulated and 34 were upregulated. Employing a hidden Markov model (HMM) algorithm, we identified downregulation of miR-374b as likely being directly involved in acquisition of the drug-resistant phenotype. Consistent with this prediction, ectopic overexpression of miR-374b in the resistant BxPC3-R cells restored cisplatin sensitivity to levels approaching those displayed by the BxPC3 parental cells. The results are consistent with a growing body of evidence implicating miRNAs in acquired cancer-drug resistance and with the potential therapeutic value of these small regulatory RNAs in blocking and/or reversing the process. PMID:27229158

  2. Carbapenem-resistant Acinetobacter baumannii acquired before liver transplantation: Impact on recipient outcomes.

    PubMed

    Freire, Maristela Pinheiro; Pierrotti, Ligia Câmera; Oshiro, Isabel Cristina Villela Soares; Bonazzi, Patrícia Rodrigues; Oliveira, Larissa Marques de; Machado, Anna Silva; Van Der Heijden, Inneke Marie; Rossi, Flavia; Costa, Silvia Figueiredo; D'Albuquerque, Luiz Augusto Carneiro; Abdala, Edson

    2016-05-01

    Infection with carbapenem-resistant Acinetobacter baumannii (CRAB) after liver transplantation (LT) is associated with high mortality. This study aimed to identify risk factors for post-LT CRAB infection, as well as to evaluate the impact of pre-LT CRAB acquisition on the incidence of post-LT CRAB infection. This was a prospective cohort study of all patients undergoing LT at our facility between October 2009 and October 2011. Surveillance cultures (SCs) were collected immediately before LT and weekly thereafter, until discharge. We analyzed 196 patients who were submitted to 222 LTs. CRAB was identified in 105 (53.6%); 24 (22.9%) of these patients were found to have acquired CRAB before LT, and 85 (81.0%) tested positive on SCs. Post-LT CRAB infection occurred in 56 (28.6%), the most common site being the surgical wound. Multivariate analysis showed that the risk factors for developing CRAB infection were prolonged cold ischemia, post-LT dialysis, LT due to fulminant hepatitis, and pre-LT CRAB acquisition with pre-LT CRAB acquisition showing a considerable trend toward significance (P = 0.06). Among the recipients with CRAB infection, 60-day mortality was 46.4%, significantly higher than among those without (P < 0.001). Mortality risk factors were post-LT infection with multidrug-resistant bacteria, LT performed because of fulminant hepatitis, retransplantation, prolonged cold ischemia, longer LT surgical time, and pre-LT CRAB acquisition, the last showing a trend toward significance (P = 0.08). In conclusion, pre-LT CRAB acquisition appears to increase the risk of post-LT CRAB infection, which has a negative impact on recipient survival. Liver Transplantation 22 615-626 2016 AASLD.

  3. Biomarkers of erlotinib response in non-small cell lung cancer tumors that do not harbor the more common epidermal growth factor receptor mutations

    PubMed Central

    López-Ayllón, Blanca D; de Castro-Carpeño, Javier; Rodriguez, Carlos; Pernía, Olga; de Cáceres, Inmaculada Ibañez; Belda-Iniesta, Cristobal; Perona, Rosario; Sastre, Leandro

    2015-01-01

    Non-small cell lung cancer (NSCLC) represents approximately 85% of all lung cancers, which are the leading cause of cancer-related deaths in the world. Tyrosine kinase inhibitors such as erlotinib represent one therapeutic options presently recommended for tumors produced by activating mutations in the gene coding of epidermal growth factor receptor (EGFR). The aim of this study is the identification of possible biomarkers for tumor sensitivity to erlotinib in the absence of the main EGFR mutations. The erlotinib sensitivity of cells isolated from 41 untreated NSCLC patients was determined and compared with the presence of the more frequent EGFR mutations. Several patients had tumor cells highly sensitive to erlitinib in the absence of the EGFR mutations analyzed. The gene expression profile of 3 erlotinib-sensitive tumors was compared with that of 4 resistant tumors by DNA microarray hybridization. Sixteen genes were expressed at significantly higher levels in the resistant tumors than in the sensitive tumors. The possible correlation between erlotinib sensitivity and the expression of these genes was further analyzed using the data for the NSCLC, breast cancer and colon cancer cell lines of the NCI60 collection. The expression of these genes was correlated with the overall survival of 5 patients treated with erlotinib, according to The Cancer Genome Atlas (TCGA) database. Overlapping groups of 7, 5 and 3 genes, including UGT1A6, TRIB3, MET, MMP7, COL17A1, LCN2 and PTPRZ1, whose expression correlated with erlotinib activity was identified. In particular, low MET expression levels showed the strongest correlation. PMID:26045797

  4. Studies on chicken acquired resistance to Argas (persicargas) persicus Latereille (Acari: Argasidae) due to repeated infestation.

    PubMed

    Habeeb, S M; Sayed, M A; El-Kammah, K M

    2001-08-01

    Spring chickens were used for feeding Argas persicus (females) daily over one week during both winter and summer seasons. Acquired resistance to ticks was monitored by: 1) failure of ticks to replenish a blood meal from chickens bitten repeatedly by the infesting ticks during winter and summer seasons; 2) measurements of anti-tick activity in the chicken sera; 3) detection of changes in their serum proteins. Chickens were bled after the 4th feeding, during the 1st, 2nd, 3rd and 4th weeks post-feeding. The titre of anti-tick antibody was determined in the chicken sera by an enzyme-linked immunosorbent assay (ELISA) technique. The change in sera protein bands after Argas persicus female repeated feeding was studied by the use of 10% SDS polyacrylamide gel electrophoresis. The results showed that the nonfeeding percentage in A. persicus was significant in both winter and summer seasons. The highest concentration of antibodies against A. persicus was detected after the fourth feeding and the lowest titre was reported in sera collected after the fourth week in both seasons. Infested chicken serum proteins electrophoresis showed different patterns of separation from the non-infested chickens. The protein bands of the noninfested chicken sera had 5 and 10 bands in the winter and summer seasons, but in infested chicken sera, it ranged between 12-17 and 14-18 bands in winter and summer seasons respectively.

  5. Length of stay an important mediator of hospital-acquired methicillin-resistant Staphylococcus aureus.

    PubMed

    Wong, J G; Chen, M I; Win, M K; Ng, P Y; Chow, A

    2016-04-01

    Hospital-acquired methicillin-resistant Staphylococcus aureus (HA-MRSA) is becoming increasingly established in Asian hospitals. The primary aim of this study was to decompose the risk factors for HA-MRSA based on conceptual clinical pathways. The secondary aim was to show the amount of effect attributable to antibiotic exposure and total length of stay before outcome (LBO) so that institutions can manage at-risk patients accordingly. A case-control study consisting of 1200 inpatients was conducted in a large tertiary hospital in Singapore between January and December 2006. Results from the generalized structural equation model (GSEM) show that LBO [adjusted odds ratio (aOR) 14·9, 95% confidence interval (CI) 8·7-25·5], prior hospitalization (aOR 6·2, 95% CI 3·3-11·5), and cumulative antibiotic exposure (aOR 3·5, 95% CI 2·3-5·3), directly affected HA-MRSA acquisition. LBO accounted for the majority of the effects due to age (100%), immunosuppression (67%), and surgery (96%), and to a lesser extent for male gender (22%). Our model enabled us to account and quantify effects of intermediaries. LBO was found to be an important mediator of age, immunosuppression and surgery on MRSA infection. Traditional regression approaches will not only give different conclusions but also underestimate the effects. Hospitals should minimize the hospital stay when possible to reduce the risk of MRSA.

  6. Surveillance of Antibiotic Resistance among Hospital- and Community-Acquired Toxigenic Clostridium difficile Isolates over 5-Year Period in Kuwait

    PubMed Central

    Jamal, Wafaa Y.; Rotimi, Vincent O.

    2016-01-01

    Clostridium difficile infection (CDI) is a leading and an important cause of diarrhea in a healthcare setting especially in industrialized countries. Community-associated CDI appears to add to the burden on healthcare setting problems. The aim of the study was to investigate the antimicrobial resistance of healthcare-associated and community-acquired C. difficile infection over 5 years (2008–2012) in Kuwait. A total of 111 hospital-acquired (HA-CD) and 35 community-acquired Clostridium difficile (CA-CD) clinical isolates from stool of patients with diarrhoea were studied. Antimicrobial susceptibility testing of 15 antimicrobial agents against these pathogens was performed using E test method. There was no evidence of resistance to amoxicillin-clavulanic acid, daptomycin, linezolid, piperacillin-tazobactam, teicoplanin and vancomycin by both HA-CD and CA-CD isolates. Metronidazole had excellent activity against CA-CD but there was a 2.9% resistance rate against HA-CD isolates. Ampicillin, clindamycin, levofloxacin and imipenem resistance rates among the HC-CD vs. CA-CD isolates were 100 vs. 47.4%; 43 vs. 47.4%; 100 vs. 100% and 100 vs. 89%, respectively. An unexpected high rifampicin resistance rate of 15.7% emerged amongst the HA-CD isolates. In conclusion, vancomycin resistance amongst the HA-CD and CA-CD isolates was not encountered in this series but few metronidazole resistant hospital isolates were isolated. High resistance rates of ampicillin, clindamycin, levofloxacin, and imipenem resistance were evident among both CA-CD and HA-CD isolates. Rifampicin resistance is emerging among the HA-CD isolates. PMID:27536994

  7. Community-acquired methicillin-resistant Staphylococcus aureus infections in two scuba divers returning from the Philippines.

    PubMed

    Bochet, Mélanie; Francois, Patrice; Longtin, Yves; Gaide, Olivier; Renzi, Gesuele; Harbarth, Stephan

    2008-01-01

    We describe two patients who had skin infection due to identical strains of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) after returning from the Philippines. Both patients did not share risk factors for CA-MRSA acquisition besides scuba diving. Scuba diving equipment may represent a possible new mode of acquisition of CA-MRSA.

  8. Saccharin-induced systemic acquired resistance against rust (Phakopsora pachyrhizi) infection in soybean: Effects on growth and development

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We examined the effect of saccharin on the systemic acquired resistance (SAR) response of soybean to the fungus Phakopsora pachyrhizi, the causal agent of soybean rust. Plants were grown hydroponically in half-strength Hoagland’s solution and were challenged with the pathogen 1, 5, 10 and 15 days af...

  9. New Real-Time PCR Assays for Detection of Inducible and Acquired Clarithromycin Resistance in the Mycobacterium abscessus Group

    PubMed Central

    Shallom, Shamira J.; Moura, Natalia S.; Olivier, Kenneth N.; Sampaio, Elizabeth P.; Holland, Steven M.

    2015-01-01

    Members of the Mycobacterium abscessus group (MAG) cause lung, soft tissue, and disseminated infections. The oral macrolides clarithromycin and azithromycin are commonly used for treatment. MAG can display clarithromycin resistance through the inducible erm(41) gene or via acquired mutations in the rrl (23S rRNA) gene. Strains harboring a truncation or a T28C substitution in erm(41) lose the inducible resistance trait. Phenotypic detection of clarithromycin resistance requires extended incubation (14 days), highlighting the need for faster methods to detect resistance. Two real-time PCR-based assays were developed to assess inducible and acquired clarithromycin resistance and tested on a total of 90 clinical and reference strains. A SYBR green assay was designed to distinguish between a full-length and truncated erm(41) gene by temperature shift in melting curve analysis. Single nucleotide polymorphism (SNP) allele discrimination assays were developed to distinguish T or C at position 28 of erm(41) and 23S rRNA rrl gene mutations at position 2058 and/or 2059. Truncated and full-size erm(41) genes were detected in 21/90 and 69/90 strains, respectively, with 64/69 displaying T at nucleotide position 28 and 5/69 containing C at that position. Fifteen isolates showed rrl mutations conferring clarithromycin resistance, including A2058G (11 isolates), A2058C (3 isolates), and A2059G (1 isolate). Targeted sequencing and phenotypic assessment of resistance concurred with molecular assay results. Interestingly, we also noted cooccurring strains harboring an active erm(41), inactive erm(41), and/or acquired mutational resistance, as well as slowly growing MAG strains and also strains displaying an inducible resistance phenotype within 5 days, long before the recommended 14-day extended incubation. PMID:26269619

  10. Co-option of Liver Vessels and Not Sprouting Angiogenesis Drives Acquired Sorafenib Resistance in Hepatocellular Carcinoma

    PubMed Central

    Kuczynski, Elizabeth A.; Yin, Melissa; Bar-Zion, Avinoam; Lee, Christina R.; Butz, Henriett; Man, Shan; Daley, Frances; Vermeulen, Peter B.; Yousef, George M.; Foster, F. Stuart

    2016-01-01

    Background: The anti-angiogenic Sorafenib is the only approved systemic therapy for advanced hepatocellular carcinoma (HCC). However, acquired resistance limits its efficacy. An emerging theory to explain intrinsic resistance to other anti-angiogenic drugs is ‘vessel co-option,’ ie, the ability of tumors to hijack the existing vasculature in organs such as the lungs or liver, thus limiting the need for sprouting angiogenesis. Vessel co-option has not been evaluated as a potential mechanism for acquired resistance to anti-angiogenic agents. Methods: To study sorafenib resistance mechanisms, we used an orthotopic human HCC model (n = 4-11 per group), where tumor cells are tagged with a secreted protein biomarker to monitor disease burden and response to therapy. Histopathology, vessel perfusion assessed by contrast-enhanced ultrasound, and miRNA sequencing and quantitative real-time polymerase chain reaction were used to monitor changes in tumor biology. Results: While sorafenib initially inhibited angiogenesis and stabilized tumor growth, no angiogenic ‘rebound’ effect was observed during development of resistance unless therapy was stopped. Instead, resistant tumors became more locally infiltrative, which facilitated extensive incorporation of liver parenchyma and the co-option of liver-associated vessels. Up to 75% (±10.9%) of total vessels were provided by vessel co-option in resistant tumors relative to 23.3% (±10.3%) in untreated controls. miRNA sequencing implicated pro-invasive signaling and epithelial-to-mesenchymal-like transition during resistance development while functional imaging further supported a shift from angiogenesis to vessel co-option. Conclusions: This is the first documentation of vessel co-option as a mechanism of acquired resistance to anti-angiogenic therapy and could have important implications including the potential therapeutic benefits of targeting vessel co-option in conjunction with vascular endothelial growth factor

  11. Bufalin reverses intrinsic and acquired drug resistance to cisplatin through the AKT signaling pathway in gastric cancer cells.

    PubMed

    Zhao, Hongyan; Zhao, Dali; Jin, Huilin; Li, Hongwei; Yang, Xiaoying; Zhuang, Liwei; Liu, Tiefu

    2016-08-01

    Cisplatin is the most common chemotherapeutic agent for gastric cancer (GC), however it activates AKT, which contributes to intrinsic and acquired resistance. Bufalin, a traditional Chinese medicine, shows significant anticancer activity by inhibiting the AKT pathway. It was therefore hypothesized that bufalin could counteract cisplatin resistance in GC cells. SGC7901, MKN‑45 and BGC823 human GC cells were cultured under normoxic and hypoxic conditions. Effects of cisplatin and bufalin on GC cells were measured by a cell counting kit, apoptosis was analyzed by flow cytometry, and immunoblotting was used to detect proteins associated with the AKT signaling pathway. It was demonstrated that bufalin synergized with cisplatin to inhibit proliferation and promote apoptosis of GC cells by diminishing the activation of cisplatin-induced AKT under normoxic and hypoxic conditions. Bufalin also inhibits cisplatin-activated molecules downstream of AKT that affect proliferation and apoptosis, including glycogen synthase kinase, mammalian target of rapamycin, ribosomal protein S6 Kinase and eukaryotic translation initiation factor-4E-binding protein-1. To investigate acquired cisplatin resistance, a cisplatin‑resistant cell line SGC7901‑CR was used. It was demonstrated that bufalin reversed acquired cisplatin resistance and significantly induced apoptosis through the AKT pathway. These results imply that bufalin could extend the therapeutic effect of cisplatin on GC cells when administered in combination. PMID:27357249

  12. Comparative efficacy of systemic acquired resistance-inducing compounds against rust infection in sunflower plants.

    PubMed

    Amzalek, Esther; Cohen, Yigal

    2007-02-01

    ABSTRACT Four inducers of systemic acquired resistance (SAR) were examined for their efficacy in controlling rust infection caused by Puccinia helianthi in sunflower plants. Of the four compounds, DL-3-amino-n-butanoic acid (DL-beta-aminobutyric acid [BABA]) was the most effective and sodium salicylate (NaSA) was the least effective in protecting against rust. In leaf disk assays, full protection was obtained with BABA at 25 mug/ml, benzodiathiazol-S-methyl ester (BTH) at 100 mug/ml, 2,6-di-chloroisonicotinic acid (INA) at 100 mug/ml, and NaSA at >200 mug/ml. L-2-amino-n-butanoic acid (AABA) was partially effective, whereas N-methyl-BABA and 4-aminobutnoic acid (GABA) were ineffective. The R-enantiomer of BABA, but not the S-enantiomer, was more effective than the racemic mixture. In intact plants, BABA applied as a foliar spray or a root dip, before or after (up to 48 h) inoculation, provided significant protection for 8 days. BTH, INA, and NaSA were less protective and more phytotoxic compared with BABA. BABA did not affect urediospore germination, germ tube growth, appressorial formation, or initial ingress of P. helianthi, but strongly suppressed mycelial colonization in the mesophyll and, consequently, pustule and urediospore formation. No accumulation of defense compounds (phenolics, lignin, or callose) was detected in BABA-treated inoculated or noninoculated plants. This is the first report on the activity of BABA against an obligate Basidomycete pathogen in planta.

  13. Proteomic analysis of acquired tamoxifen resistance in MCF-7 cells reveals expression signatures associated with enhanced migration

    PubMed Central

    2012-01-01

    Introduction Acquired tamoxifen resistance involves complex signaling events that are not yet fully understood. Successful therapeutic intervention to delay the onset of hormone resistance depends critically on mechanistic elucidation of viable molecular targets associated with hormone resistance. This study was undertaken to investigate the global proteomic alterations in a tamoxifen resistant MCF-7 breast cancer cell line obtained by long term treatment of the wild type MCF-7 cell line with 4-hydroxytamoxifen (4-OH Tam). Methods We cultured MCF-7 cells with 4-OH Tam over a period of 12 months to obtain the resistant cell line. A gel-free, quantitative proteomic method was used to identify and quantify the proteome of the resistant cell line. Nano-flow high-performance liquid chromatography coupled to high resolution Fourier transform mass spectrometry was used to analyze fractionated peptide mixtures that were isobarically labeled from the resistant and control cell lysates. Real time quantitative PCR and Western blots were used to verify selected proteomic changes. Lentiviral vector transduction was used to generate MCF-7 cells stably expressing S100P. Online pathway analysis was performed to assess proteomic signatures in tamoxifen resistance. Survival analysis was done to evaluate clinical relevance of altered proteomic expressions. Results Quantitative proteomic analysis revealed a wide breadth of signaling events during transition to acquired tamoxifen resistance. A total of 629 proteins were found significantly changed with 364 up-regulated and 265 down-regulated. Collectively, these changes demonstrated the suppressed state of estrogen receptor (ER) and ER-regulated genes, activated survival signaling and increased migratory capacity of the resistant cell line. The protein S100P was found to play a critical role in conferring tamoxifen resistance and enhanced cell motility. Conclusions Our data demonstrate that the adaptive changes in the proteome of

  14. Acquired resistance to daunorubicin in a patient with acute myelogenous leukaemia.

    PubMed Central

    Smith, B. J.; Kundu, D.

    1976-01-01

    Measurement of in vitro and in vivo resistance to daunorubicin in AML patients suggests that there is no simple correlation between the two. In a patient who became clinically resistant and whose cells showed a parallel increased resistance in vitro we found the acquisition of multiple drug resistance. The increased in vitro resistance to daunorubicin could to some extent be overcome by conjugating daunorubicin to DNA. PMID:1066148

  15. Acquisition of a single EZH2 D1 domain mutation confers acquired resistance to EZH2-targeted inhibitors

    PubMed Central

    Baker, Theresa; Nerle, Sujata; Pritchard, Justin; Zhao, Boyang; Rivera, Victor M.

    2015-01-01

    Although targeted therapies have revolutionized cancer treatment, overcoming acquired resistance remains a major clinical challenge. EZH2 inhibitors (EZH2i), EPZ-6438 and GSK126, are currently in the early stages of clinical evaluation and the first encouraging signs of efficacy have recently emerged in the clinic. To anticipate mechanisms of resistance to EZH2i, we used a forward genetic platform combining a mutagenesis screen with next generation sequencing technology and identified a hotspot of secondary mutations in the EZH2 D1 domain (Y111 and I109). Y111D mutation within the WT or A677G EZH2 allele conferred robust resistance to both EPZ-6438 and GSK126, but it only drove a partial resistance within the Y641F allele. EZH2 mutants required histone methyltransferase (HMT) catalytic activity and the polycomb repressive complex 2 (PRC2) components, SUZ12 and EED, to drive drug resistance. Furthermore, D1 domain mutations not only blocked the ability of EZH2i to bind to WT and A677G mutant, but also abrogated drug binding to the Y641F mutant. These data provide the first cellular validation of the mechanistic model underpinning the oncogenic function of WT and mutant EZH2. Importantly, our findings suggest that acquired-resistance to EZH2i may arise in WT and mutant EZH2 patients through a single mutation that remains targetable by second generation EZH2i. PMID:26360609

  16. Benznidazole-Resistance in Trypanosoma cruzi Is a Readily Acquired Trait That Can Arise Independently in a Single Population

    PubMed Central

    Mejia, Ana Maria; Hall, Belinda S.; Taylor, Martin C.; Gómez-Palacio, Andrés; Wilkinson, Shane R.; Triana-Chávez, Omar; Kelly, John M.

    2012-01-01

    Benznidazole is the frontline drug used against Trypanosoma cruzi, the causative agent of Chagas disease. However, treatment failures are often reported. Here, we demonstrate that independently acquired mutations in the gene encoding a mitochondrial nitroreductase (TcNTR) can give rise to distinct drug-resistant clones within a single population. Following selection of benznidazole-resistant parasites, all clones examined had lost one of the chromosomes containing the TcNTR gene. Sequence analysis of the remaining TcNTR allele revealed 3 distinct mutant genes in different resistant clones. Expression studies showed that these mutant proteins were unable to activate benznidazole. This correlated with loss of flavin mononucleotide binding. The drug-resistant phenotype could be reversed by transfection with wild-type TcNTR. These results identify TcNTR as a central player in acquired resistance to benznidazole. They also demonstrate that T. cruzi has a propensity to undergo genetic changes that can lead to drug resistance, a finding that has implications for future therapeutic strategies. PMID:22551809

  17. A Nexus Consisting of Beta-Catenin and Stat3 Attenuates BRAF Inhibitor Efficacy and Mediates Acquired Resistance to Vemurafenib.

    PubMed

    Sinnberg, Tobias; Makino, Elena; Krueger, Marcel A; Velic, Ana; Macek, Boris; Rothbauer, Ulrich; Groll, Nicola; Pötz, Oliver; Czemmel, Stefan; Niessner, Heike; Meier, Friedegund; Ikenberg, Kristian; Garbe, Claus; Schittek, Birgit

    2016-06-01

    Acquired resistance to second generation BRAF inhibitors (BRAFis), like vemurafenib is limiting the benefits of long term targeted therapy for patients with malignant melanomas that harbor BRAF V600 mutations. Since many resistance mechanisms have been described, most of them causing a hyperactivation of the MAPK- or PI3K/AKT signaling pathways, one potential strategy to overcome BRAFi resistance in melanoma cells would be to target important common signaling nodes. Known factors that cause secondary resistance include the overexpression of receptor tyrosine kinases (RTKs), alternative splicing of BRAF or the occurrence of novel mutations in MEK1 or NRAS. In this study we show that β-catenin is stabilized and translocated to the nucleus in approximately half of the melanomas that were analyzed and which developed secondary resistance towards BRAFi. We further demonstrate that β-catenin is involved in the mediation of resistance towards vemurafenib in vitro and in vivo. Unexpectedly, β-catenin acts mainly independent of the TCF/LEF dependent canonical Wnt-signaling pathway in resistance development, which partly explains previous contradictory results about the role of β-catenin in melanoma progression and therapy resistance. We further demonstrate that β-catenin interacts with Stat3 after chronic vemurafenib treatment and both together cooperate in the acquisition and maintenance of resistance towards BRAFi. PMID:27428425

  18. An Autopsy Case of Two Distinct, Acquired Drug Resistance Mechanisms in Epidermal Growth Factor Receptor-mutant Lung Adenocarcinoma: Small Cell Carcinoma Transformation and Epidermal Growth Factor Receptor T790M Mutation.

    PubMed

    Furugen, Makoto; Uechi, Kayoko; Hirai, Jun; Aoyama, Hajime; Saio, Masanao; Yoshimi, Naoki; Kinjo, Takeshi; Miyagi, Kazuya; Haranaga, Shusaku; Higa, Futoshi; Tateyama, Masao; Fujita, Jiro

    2015-01-01

    We herein describe the case of a 63-year-old man who died from relapsed epidermal growth factor receptor gene (EGFR) exon 19 deletion lung adenocarcinoma treated with erlotinib. According to the autopsy results, he was confirmed to have small cell carcinoma without the EGFR T790M mutation in his pancreas and left kidney metastatic specimens, while the adenocarcinoma metastatic lesion in his right kidney had the EGFR T790M mutation; both retained the somatic EGFR exon 19 deletion. We herein report an autopsy case of resistance to an EGFR tyrosine kinase inhibitor via small cell carcinoma transformation and the EGFRT790M mutation in separate metastatic organs. PMID:26424310

  19. Erlotinib-related keratopathy in a patient underwent laser in situ keratomileusis.

    PubMed

    Kau, Hui-Chuan; Tsai, Chieh-Chih

    2016-09-01

    Erlotinib is a tyrosine kinase inhibitor of the epidermal growth factor receptor. Since there is a wide expression of the epidermal growth factor receptors in the epithelial tissues of ocular surface and adnexa, ocular adverse reactions may happen during systemic administration of erlotinib. Previously reported ocular adverse reactions of erlotinib include trichomegaly, periorbital rash, ectropion, blepharitis, persistent corneal epithelial defect, corneal ulcer and perforation. We report the first case of erlotinib-related keratopathy in a patient who had received laser in situ keratomileusis. The patient presented a special picture of flap striae related to erlotinib. Improvement of keratopathy after cessation of erlotinib was demonstrated. PMID:26340340

  20. D538G mutation in estrogen receptor-α: A novel mechanism for acquired endocrine resistance in breast cancer.

    PubMed

    Merenbakh-Lamin, Keren; Ben-Baruch, Noa; Yeheskel, Adva; Dvir, Addie; Soussan-Gutman, Lior; Jeselsohn, Rinath; Yelensky, Roman; Brown, Myles; Miller, Vincent A; Sarid, David; Rizel, Shulamith; Klein, Baruch; Rubinek, Tami; Wolf, Ido

    2013-12-01

    Resistance to endocrine therapy occurs in virtually all patients with estrogen receptor α (ERα)-positive metastatic breast cancer, and is attributed to various mechanisms including loss of ERα expression, altered activity of coregulators, and cross-talk between the ERα and growth factor signaling pathways. To our knowledge, acquired mutations of the ERα have not been described as mediating endocrine resistance. Samples of 13 patients with metastatic breast cancer were analyzed for mutations in cancer-related genes. In five patients who developed resistance to hormonal therapy, a mutation of A to G at position 1,613 of ERα, resulting in a substitution of aspartic acid at position 538 to glycine (D538G), was identified in liver metastases. Importantly, the mutation was not detected in the primary tumors obtained prior to endocrine treatment. Structural modeling indicated that D538G substitution leads to a conformational change in the ligand-binding domain, which mimics the conformation of activated ligand-bound receptor and alters binding of tamoxifen. Indeed, experiments in breast cancer cells indicated constitutive, ligand-independent transcriptional activity of the D538G receptor, and overexpression of it enhanced proliferation and conferred resistance to tamoxifen. These data indicate a novel mechanism of acquired endocrine resistance in breast cancer. Further studies are needed to assess the frequency of D538G-ERα among patients with breast cancer and explore ways to inhibit its activity and restore endocrine sensitivity.

  1. Acquired resistance to the second-generation androgen receptor antagonist enzalutamide in castration-resistant prostate cancer

    PubMed Central

    Kregel, Steven; Chen, James L.; Tom, Westin; Krishnan, Venkatesh; Kach, Jacob; Brechka, Hannah; Fessenden, Tim B.; Isikbay, Masis; Paner, Gladell P.

    2016-01-01

    Enzalutamide (MDV3100) is a second generation Androgen Receptor (AR) antagonist with proven efficacy in the treatment of castration resistant prostate cancer (CRPC). The majority of treated patients, however, develop resistance and disease progression and there is a critical need to identify novel targetable pathways mediating resistance. The purpose of this study was to develop and extensively characterize a series of enzalutamide-resistant prostate cancer cell lines. Four genetically distinct AR-positive and AR-pathway dependent prostate cancer cell lines (CWR-R1, LAPC-4, LNCaP, VCaP) were made resistant to enzalutamide by long-term culture (> 6 months) in enzalutamide. Extensive characterization of these lines documented divergent in vitro growth characteristics and AR pathway modulation. Enzalutamide-resistant LNCaP and CWR-R1 cells, but not LAPC-4 and VCAP cells, demonstrated increased castration-resistant and metastatic growth in vivo. Global gene expression analyses between short-term enzalutamide treated vs. enzalutamide-resistant cells identified both AR pathway and non-AR pathway associated changes that were restored upon acquisition of enzalutamide resistance. Further analyses revealed very few common gene expression changes between the four resistant cell lines. Thus, while AR-mediated pathways contribute in part to enzalutamide resistance, an unbiased approach across several cell lines demonstrates a greater contribution toward resistance via pleiotropic, non-AR mediated mechanisms. PMID:27036029

  2. Telomerase activity and telomere length in human tumor cells with acquired resistance to anticancer agents.

    PubMed

    Smith, V; Dai, F; Spitz, M; Peters, G J; Fiebig, H H; Hussain, A; Burger, A M

    2009-11-01

    Telomeres and telomerase are targets for anticancer drug development and specific inhibitors are currently under clinical investigation. However, it has been reported that standard cytotoxic agents can affect telomere length and telomerase activity suggesting that they also have of a role in drug resistance. in this study, telomere lengths and telomerase activity as well as drug efflux pump expression, glutathione (GSH) levels and polyadenosine-ribose polymerase (PARP) cleavage were assessed in a panel of human tumor cell lines made resistant to vindesine, gemcitabine and cisplatin. these included two lung cancer cell lines resistant to vindesine (LXFL 529L/Vind, LXFA 526L/Vind), a renal cancer cell line (RXF944L/Gem) and an ovarian cancer cell line (AG6000) resistant to gemcitabine, and one resistant to cisplatin (ADDP). The resistant clones were compared to their parental lines and evaluated for cross resistance to other cytotoxic agents. Several drug specific resistance patterns were found, and various complex patterns of cross resistance emerged from some cell lines, but these mechanisms of resistance could not be related to drug efflux pump expression, GSH levels or pARp cleavage. However, all displayed changes in telomerase activity and/or telomere length. Our studies present evidence that telomere maintenance should be taken into consideration in efforts not only to overcome drug resistance, but also to optimize the use of telomere-based therapeutics.

  3. Acquired multi-azole resistance in Candida tropicalis during persistent urinary tract infection in a dog.

    PubMed

    Álvarez-Pérez, Sergio; García, Marta E; Cutuli, María Teresa; Fermín, María Luisa; Daza, María Ángeles; Peláez, Teresa; Blanco, José L

    2016-03-01

    Multi-azole resistance acquisition by Candida tropicalis after prolonged antifungal therapy in a dog with urinary candidiasis is reported. Pre- and post-azole treatment isolates were clonally related and had identical silent mutations in the ERG11 gene, but the latter displayed increased azole minimum inhibitory concentrations. A novel frameshift mutation in ERG3 was found in some isolates recovered after resistance development, so it appears unlikely that this mutation is responsible for multi-azole resistance.

  4. Proteomic Signatures of Acquired Letrozole Resistance in Breast Cancer: Suppressed Estrogen Signaling and Increased Cell Motility and Invasiveness*

    PubMed Central

    Tilghman, Syreeta L.; Townley, Ian; Zhong, Qiu; Carriere, Patrick P.; Zou, Jin; Llopis, Shawn D.; Preyan, Lynez C.; Williams, Christopher C.; Skripnikova, Elena; Bratton, Melyssa R.; Zhang, Qiang; Wang, Guangdi

    2013-01-01

    Aromatase inhibitors, such as letrozole, have become the first-line treatment for postmenopausal women with estrogen-dependent breast cancer. However, acquired resistance remains a major clinical obstacle. Previous studies demonstrated constitutive activation of the MAPK signaling, overexpression of HER2, and down-regulation of aromatase and ERα in letrozole-resistant breast cancer cells. Given the complex signaling network involved in letrozole-refractory breast cancer and the lack of effective treatment for hormone resistance, further investigation of aromatase inhibitor resistance by a novel systems biology approach may reveal previously unconsidered molecular changes that could be utilized as therapeutic targets. This study was undertaken to characterize for the first time global proteomic alterations occurring in a letrozole-resistant cell line. A quantitative proteomic analysis of the whole cell lysates of LTLT-Ca (resistant) versus AC-1 cells (sensitive) was performed to identify significant protein expression changes. A total of 1743 proteins were identified and quantified, of which 411 were significantly up-regulated and 452 significantly down-regulated (p < 0.05, fold change > 1.20). Bioinformatics analysis revealed that acquired letrozole resistance is associated with a hormone-independent, more aggressive phenotype. LTLT-Ca cells exhibited 84% and 138% increase in migration and invasion compared with the control cells. The ROCK inhibitor partially abrogated the enhanced migration and invasion of the letrozole-resistant cells. Flow cytometric analyses also demonstrated an increase in vimentin and twist expression in letrozole-resistance cells, suggesting an onset of epithelial to mesenchymal transition (EMT). Moreover, targeted gene expression arrays confirmed a 28-fold and sixfold up-regulation of EGFR and HER2, respectively, whereas ERα and pS2 were dramatically reduced by 28-fold and 1100-fold, respectively. Taken together, our study revealed global

  5. Multiple transport systems mediate virus-induced acquired resistance to oxidative stress

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this paper, we report the phenomenon of acquired cross-tolerance to oxidative (UV-C and H2O2) stress in Nicotiana benthamiana plants infected with Potato virus X (PVX) and investigate the functional expression of transport systems in mediating this phenomenon. By combining multiple approaches, we...

  6. JNK Pathway Activation Modulates Acquired Resistance to EGFR/HER2-Targeted Therapies.

    PubMed

    Manole, Simin; Richards, Edward J; Meyer, Aaron S

    2016-09-15

    Resistance limits the effectiveness of receptor tyrosine kinase (RTK)-targeted therapies. Combination therapies targeting resistance mechanisms can considerably improve response, but will require an improved understanding of when particular combinations will be effective. One common form of resistance is bypass signaling, wherein RTKs not targeted by an inhibitor can direct reactivation of pathways essential for survival. Although this mechanism of resistance is well appreciated, it is unclear which downstream signaling events are responsible. Here, we apply a combined experimental- and statistical modeling-based approach to identify a set of pathway reactivation essential for RTK-mediated bypass resistance. Differences in the downstream pathway activation provided by particular RTKs lead to qualitative differences in the capacity of each receptor to drive therapeutic resistance. We identify and validate that the JNK pathway is activated during and strongly modulates bypass resistance. These results identify effective therapeutic combinations that block bypass-mediated resistance and provide a basic understanding of this network-level change in kinase dependence that will inform the design of prognostic assays for identifying effective therapeutic combinations in individual patients. Cancer Res; 76(18); 5219-28. ©2016 AACR. PMID:27450453

  7. Recall of acquired cellular resistance in mice by antigens from killed Brucella.

    PubMed

    Halliburton, B L; Hinsdill, R D

    1972-01-01

    Mice infected with Brucella abortus 19 were challenged intravenously with Listeria monocytogenes. Spleen assays to determine the number of viable Listeria cells present revealed that these mice were highly resistant to Listeria when challenged on day 17 of the Brucella infection. Resistance was absent in mice challenged on the 5th day and was declining in mice challenged on the 33rd day. Resistance could not be detected by day 49 of the Brucella infection but could be recalled by the injection of antigens from smooth B. abortus 2308. Thus, extracted antigens appeared to be as effective in recall as the live cells used in earlier studies. Similar injections of extracts from rough B. abortus 45/20, or from B. ovis REO 198, were also effective in recalling resistance; this suggests that the smooth surface agglutinogen may be relatively unimportant in recall. PMID:4632467

  8. Update on the prevention and control of community-acquired meticillin-resistant Staphylococcus aureus (CA-MRSA).

    PubMed

    Skov, Robert; Christiansen, Keryn; Dancer, Stephanie J; Daum, Robert S; Dryden, Matthew; Huang, Yhu-Chering; Lowy, Franklin D

    2012-03-01

    The rapid dissemination of community-acquired meticillin-resistant Staphylococcus aureus (CA-MRSA) since the early 2000s and the appearance of new successful lineages is a matter of concern. The burden of these infections varies widely between different groups of individuals and in different regions of the world. Estimating the total burden of disease is therefore problematic. Skin and soft-tissue infections, often in otherwise healthy young individuals, are the most common clinical manifestation of these infections. The antibiotic susceptibilities of these strains also vary, although they are often more susceptible to 'traditional' antibiotics than related hospital-acquired strains. Preventing the dissemination of these organisms throughout the general population requires a multifaceted approach, including screening and decolonisation, general hygiene and cleaning measures, antibiotic stewardship programmes and, in the future, vaccination. The current evidence on the prevention and control of CA-MRSA is appraised and summarised in this review.

  9. Blockade of EGFR and MEK intercepts heterogeneous mechanisms of acquired resistance to anti-EGFR therapies in colorectal cancer.

    PubMed

    Misale, Sandra; Arena, Sabrina; Lamba, Simona; Siravegna, Giulia; Lallo, Alice; Hobor, Sebastijan; Russo, Mariangela; Buscarino, Michela; Lazzari, Luca; Sartore-Bianchi, Andrea; Bencardino, Katia; Amatu, Alessio; Lauricella, Calogero; Valtorta, Emanuele; Siena, Salvatore; Di Nicolantonio, Federica; Bardelli, Alberto

    2014-02-19

    Colorectal cancers (CRCs) that are sensitive to the anti-epidermal growth factor receptor (EGFR) antibodies cetuximab or panitumumab almost always develop resistance within several months of initiating therapy. We report the emergence of polyclonal KRAS, NRAS, and BRAF mutations in CRC cells with acquired resistance to EGFR blockade. Regardless of the genetic alterations, resistant cells consistently displayed mitogen-activated protein kinase kinase (MEK) and extracellular signal-regulated kinase (ERK) activation, which persisted after EGFR blockade. Inhibition of MEK1/2 alone failed to impair the growth of resistant cells in vitro and in vivo. An RNA interference screen demonstrated that suppression of EGFR, together with silencing of MEK1/2, was required to hamper the proliferation of resistant cells. Indeed, concomitant pharmacological blockade of MEK and EGFR induced prolonged ERK inhibition and severely impaired the growth of resistant tumor cells. Heterogeneous and concomitant mutations in KRAS and NRAS were also detected in plasma samples from patients who developed resistance to anti-EGFR antibodies. A mouse xenotransplant from a CRC patient who responded and subsequently relapsed upon EGFR therapy showed exquisite sensitivity to combinatorial treatment with MEK and EGFR inhibitors. Collectively, these results identify genetically distinct mechanisms that mediate secondary resistance to anti-EGFR therapies, all of which reactivate ERK signaling. These observations provide a rational strategy to overcome the multifaceted clonal heterogeneity that emerges when tumors are treated with targeted agents. We propose that MEK inhibitors, in combination with cetuximab or panitumumab, should be tested in CRC patients who become refractory to anti-EGFR therapies.

  10. MicroRNA-138 promotes acquired alkylator resistance in glioblastoma by targeting the Bcl-2-interacting mediator BIM

    PubMed Central

    Stojcheva, Nina; Schechtmann, Gennadi; Sass, Steffen; Roth, Patrick; Florea, Ana-Maria; Stefanski, Anja; Stühler, Kai; Wolter, Marietta; Müller, Nikola S.; Theis, Fabian J.; Weller, Michael; Reifenberger, Guido; Happold, Caroline

    2016-01-01

    Glioblastoma is the most aggressive brain tumor in adults with a median survival below 12 months in population-based studies. The main reason for tumor recurrence and progression is constitutive or acquired resistance to the standard of care of surgical resection followed by radiotherapy with concomitant and adjuvant temozolomide (TMZ/RT→TMZ). Here, we investigated the role of microRNA (miRNA) alterations as mediators of alkylator resistance in glioblastoma cells. Using microarray-based miRNA expression profiling of parental and TMZ-resistant cultures of three human glioma cell lines, we identified a set of differentially expressed miRNA candidates. From these, we selected miR-138 for further functional analyses as this miRNA was not only upregulated in TMZ-resistant versus parental cells, but also showed increased expression in vivo in recurrent glioblastoma tissue samples after TMZ/RT→TMZ treatment. Transient transfection of miR-138 mimics in glioma cells with low basal miR-138 expression increased glioma cell proliferation. Moreover, miR-138 overexpression increased TMZ resistance in long-term glioblastoma cell lines and glioma initiating cell cultures. The apoptosis regulator BIM was identified as a direct target of miR-138, and its silencing mediated the induced TMZ resistance phenotype. Altered sensitivity to apoptosis played only a minor role in this resistance mechanism. Instead, we identified the induction of autophagy to be regulated downstream of the miR-138/BIM axis and to promote cell survival following TMZ exposure. Our data thus define miR-138 as a glioblastoma cell survival-promoting miRNA associated with resistance to TMZ therapy in vitro and with tumor progression in vivo. PMID:26887050

  11. A window of opportunity study of potential tumor and soluble biomarkers of response to preoperative erlotinib in early stage non-small cell lung cancer

    PubMed Central

    Sacher, Adrian G.; Le, Lisa W.; Lara-Guerra, Humberto; Waddell, Thomas K.; Sakashita, Shingo; Chen, Zhuo; Kim, Lucia; Zhang, Tong; Kamel-Reid, Suzanne; Salvarrey, Alexandra; Darling, Gail; Yasufuku, Kazuhiro; Keshavjee, Shaf; de Perrot, Marc; Shepherd, Frances A.; Liu, Geoffrey; Tsao, Ming Sound; Leighl, Natasha B.

    2016-01-01

    Background: Erlotinib is highly active in EGFR mutant NSCLC, but may benefit some with wild-type tumors. We examined pre-operative erlotinib in early stage NSCLC to assess response and correlation with potential biomarkers. Results: Twenty-five patients were enrolled; 22 received erlotinib treatment and were evaluable (median follow-up 4.4 years). Histology was predominantly adenocarcinoma although 31% had squamous carcinoma. PET response was observed in 2 patients (9%), both with squamous carcinoma. Most (20/22) had stable disease (RECIST), with frequent minor radiographic regression and histologic findings of fibrosis/necrosis including in squamous histology. Only two had EGFR mutations identified, one with minor radiographic response and the other stable disease after 4 weeks of EGFR TKI. High pre-treatment serum levels of TGF-α correlated with primary resistance to erlotinib (p = 0.02), whereas high post-treatment soluble EGFR levels correlated with response (p = 0.03). EGFR, PTEN, cMET and AXL expression did not correlate with tumor response. Methods: Clinical stage IA–IIB NSCLC patients received erlotinib 150 mg daily for 4 weeks followed by resection. Tumor response was assessed using CT, PET and pathological response. Tumor genotype was established using Sequenom Mass ARRAY; EGFR, PTEN, cMET and AXL expression was assessed by immunohistochemistry, circulating markers of EGFR activation (TGF-α, amphiregulin, epiregulin, EGFR ECD) by ELISA and EGFR, MET copy number by FISH. Conclusions: Erlotinib appears to demonstrate activity in EGFR wild-type tumors including squamous carcinoma. Further research is needed to characterize those wild-type patients that may benefit from EGFR TKI and predictive biomarkers including TGF-α, EGFR copy and others. PMID:27028852

  12. Emergence of Multidrug-Resistant Campylobacter Species Isolates with a Horizontally Acquired rRNA Methylase

    PubMed Central

    Wang, Yang; Zhang, Maojun; Deng, Fengru; Shen, Zhangqi; Wu, Congming; Zhang, Jianzhong

    2014-01-01

    Antibiotic-resistant Campylobacter constitutes a serious threat to public health, and resistance to macrolides is of particular concern, as this class of antibiotics is the drug of choice for clinical therapy of campylobacteriosis. Very recently, a horizontally transferrable macrolide resistance mediated by the rRNA methylase gene erm(B) was reported in a Campylobacter coli isolate, but little is known about the dissemination of erm(B) among Campylobacter isolates and the association of erm(B)-carrying isolates with clinical disease. To address this question and facilitate the control of antibiotic-resistant Campylobacter, we determined the distribution of erm(B) in 1,554 C. coli and Campylobacter jejuni isolates derived from food-producing animals and clinically confirmed human diarrheal cases. The results revealed that 58 of the examined isolates harbored erm(B) and exhibited high-level resistance to macrolides, and most were recent isolates, derived in 2011-2012. In addition, the erm(B)-positive isolates were all resistant to fluoroquinolones, another clinically important antibiotic used for treating campylobacteriosis. The erm(B) gene is found to be associated with chromosomal multidrug resistance genomic islands (MDRGIs) of Gram-positive origin or with plasmids of various sizes. All MDRGIs were transferrable to macrolide-susceptible C. jejuni by natural transformation under laboratory conditions. Molecular typing of the erm(B)-carrying isolates by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) identified diverse genotypes and outbreak-associated diarrheal isolates. Molecular typing also suggested zoonotic transmission of erm(B)-positive Campylobacter. These findings reveal an emerging and alarming trend of dissemination of erm(B) and MDRGIs in Campylobacter and underscore the need for heightened efforts to control their further spread. PMID:24982085

  13. Mechanisms of acquired resistance to insulin-like growth factor 1 receptor inhibitor in MCF-7 breast cancer cell line.

    PubMed

    Ekyalongo, Roudy Chiminch; Mukohara, Toru; Kataoka, Yu; Funakoshi, Yohei; Tomioka, Hideo; Kiyota, Naomi; Fujiwara, Yutaka; Minami, Hironobu

    2013-04-01

    The purpose of this study was to clarify the mechanism of acquired resistance to the insulin-like growth factor-1 receptor (IGF-1R) tyrosine kinase inhibitor NVP-AEW541. We developed an acquired resistant model by continuously exposing MCF-7 breast cancer cells to NVP-AEW541 (MCF-7-NR). MCF-7 and MCF-7-NR were comparatively analyzed for cell signaling and cell growth. While phosphorylation of Akt was completely inhibited by 3 μM NVP-AEW541 in both MCF-7 and MCF-7-NR, phosphorylation of S6K remained high only in MCF-7-NR, suggesting a disconnection between Akt and S6K in MCF-7-NR. Consistently, the mTOR inhibitor everolimus inhibited phosphorylation of S6K and cell growth equally in both lines. Screening of both lines for phosphorylation of 42 receptor tyrosine kinases with and without NVP-AEW541 showed that Tyro3 phosphorylation remained high only in MCF-7-NR. Protein expression of Tyro3 was found to be higher in MCF-7-NR than in MCF-7. Gene silencing of Tyro3 using siRNA resulted in reduced cell growth and cyclin D1 expression in both lines. While Tyro3 expression was inhibited by NVP-AEW541 and everolimus in MCF-7, it was reduced only by everolimus in MCF-7-NR. These findings suggested that cyclin D1 expression was regulated in a S6K/Tyro3-dependent manner in both MCF-7 and MCF-7-NR, and that the disconnection between IGF-1R/Akt and S6K may enable MCF-7-NR to keep cyclin D1 high in the presence of NVP-AEW541. In summary, acquired resistance to NVP-AEW541 appears to result from IGF-1R/Akt-independent activation of S6K and expression of Tyro3 and cyclin D1.

  14. Bacterial Etiology and Antibiotic Resistance Profile of Community-Acquired Urinary Tract Infections in a Cameroonian City.

    PubMed

    Nzalie, Rolf Nyah-Tuku; Gonsu, Hortense Kamga; Koulla-Shiro, Sinata

    2016-01-01

    Introduction. Community-acquired urinary tract infections (CAUTIs) are usually treated empirically. Geographical variations in etiologic agents and their antibiotic sensitivity patterns are common. Knowledge of antibiotic resistance trends is important for improving evidence-based recommendations for empirical treatment of UTIs. Our aim was to determine the major bacterial etiologies of CAUTIs and their antibiotic resistance patterns in a cosmopolitan area of Cameroon for comparison with prescription practices of local physicians. Methods. We performed a cross-sectional descriptive study at two main hospitals in Yaoundé, collecting a clean-catch mid-stream urine sample from 92 patients having a clinical diagnosis of UTI. The empirical antibiotherapy was noted, and identification of bacterial species was done on CLED agar; antibiotic susceptibility testing was performed using the Kirby-Bauer disc diffusion method. Results. A total of 55 patients had samples positive for a UTI. Ciprofloxacin and amoxicillin/clavulanic acid were the most empirically prescribed antibiotics (30.9% and 23.6%, resp.); bacterial isolates showed high prevalence of resistance to both compounds. Escherichia coli (50.9%) was the most common pathogen, followed by Klebsiella pneumoniae (16.4%). Prevalence of resistance for ciprofloxacin was higher compared to newer quinolones. Conclusions. E. coli and K. pneumoniae were the predominant bacterial etiologies; the prevalence of resistance to commonly prescribed antibiotics was high. PMID:27667998

  15. Bacterial Etiology and Antibiotic Resistance Profile of Community-Acquired Urinary Tract Infections in a Cameroonian City

    PubMed Central

    Gonsu, Hortense Kamga; Koulla-Shiro, Sinata

    2016-01-01

    Introduction. Community-acquired urinary tract infections (CAUTIs) are usually treated empirically. Geographical variations in etiologic agents and their antibiotic sensitivity patterns are common. Knowledge of antibiotic resistance trends is important for improving evidence-based recommendations for empirical treatment of UTIs. Our aim was to determine the major bacterial etiologies of CAUTIs and their antibiotic resistance patterns in a cosmopolitan area of Cameroon for comparison with prescription practices of local physicians. Methods. We performed a cross-sectional descriptive study at two main hospitals in Yaoundé, collecting a clean-catch mid-stream urine sample from 92 patients having a clinical diagnosis of UTI. The empirical antibiotherapy was noted, and identification of bacterial species was done on CLED agar; antibiotic susceptibility testing was performed using the Kirby-Bauer disc diffusion method. Results. A total of 55 patients had samples positive for a UTI. Ciprofloxacin and amoxicillin/clavulanic acid were the most empirically prescribed antibiotics (30.9% and 23.6%, resp.); bacterial isolates showed high prevalence of resistance to both compounds. Escherichia coli (50.9%) was the most common pathogen, followed by Klebsiella pneumoniae (16.4%). Prevalence of resistance for ciprofloxacin was higher compared to newer quinolones. Conclusions. E. coli and K. pneumoniae were the predominant bacterial etiologies; the prevalence of resistance to commonly prescribed antibiotics was high.

  16. Bacterial Etiology and Antibiotic Resistance Profile of Community-Acquired Urinary Tract Infections in a Cameroonian City

    PubMed Central

    Gonsu, Hortense Kamga; Koulla-Shiro, Sinata

    2016-01-01

    Introduction. Community-acquired urinary tract infections (CAUTIs) are usually treated empirically. Geographical variations in etiologic agents and their antibiotic sensitivity patterns are common. Knowledge of antibiotic resistance trends is important for improving evidence-based recommendations for empirical treatment of UTIs. Our aim was to determine the major bacterial etiologies of CAUTIs and their antibiotic resistance patterns in a cosmopolitan area of Cameroon for comparison with prescription practices of local physicians. Methods. We performed a cross-sectional descriptive study at two main hospitals in Yaoundé, collecting a clean-catch mid-stream urine sample from 92 patients having a clinical diagnosis of UTI. The empirical antibiotherapy was noted, and identification of bacterial species was done on CLED agar; antibiotic susceptibility testing was performed using the Kirby-Bauer disc diffusion method. Results. A total of 55 patients had samples positive for a UTI. Ciprofloxacin and amoxicillin/clavulanic acid were the most empirically prescribed antibiotics (30.9% and 23.6%, resp.); bacterial isolates showed high prevalence of resistance to both compounds. Escherichia coli (50.9%) was the most common pathogen, followed by Klebsiella pneumoniae (16.4%). Prevalence of resistance for ciprofloxacin was higher compared to newer quinolones. Conclusions. E. coli and K. pneumoniae were the predominant bacterial etiologies; the prevalence of resistance to commonly prescribed antibiotics was high. PMID:27667998

  17. Bacterial Etiology and Antibiotic Resistance Profile of Community-Acquired Urinary Tract Infections in a Cameroonian City.

    PubMed

    Nzalie, Rolf Nyah-Tuku; Gonsu, Hortense Kamga; Koulla-Shiro, Sinata

    2016-01-01

    Introduction. Community-acquired urinary tract infections (CAUTIs) are usually treated empirically. Geographical variations in etiologic agents and their antibiotic sensitivity patterns are common. Knowledge of antibiotic resistance trends is important for improving evidence-based recommendations for empirical treatment of UTIs. Our aim was to determine the major bacterial etiologies of CAUTIs and their antibiotic resistance patterns in a cosmopolitan area of Cameroon for comparison with prescription practices of local physicians. Methods. We performed a cross-sectional descriptive study at two main hospitals in Yaoundé, collecting a clean-catch mid-stream urine sample from 92 patients having a clinical diagnosis of UTI. The empirical antibiotherapy was noted, and identification of bacterial species was done on CLED agar; antibiotic susceptibility testing was performed using the Kirby-Bauer disc diffusion method. Results. A total of 55 patients had samples positive for a UTI. Ciprofloxacin and amoxicillin/clavulanic acid were the most empirically prescribed antibiotics (30.9% and 23.6%, resp.); bacterial isolates showed high prevalence of resistance to both compounds. Escherichia coli (50.9%) was the most common pathogen, followed by Klebsiella pneumoniae (16.4%). Prevalence of resistance for ciprofloxacin was higher compared to newer quinolones. Conclusions. E. coli and K. pneumoniae were the predominant bacterial etiologies; the prevalence of resistance to commonly prescribed antibiotics was high.

  18. Quinolone resistant Aeromonas spp. as carriers and potential tracers of acquired antibiotic resistance in hospital and municipal wastewater.

    PubMed

    Varela, Ana Rita; Nunes, Olga C; Manaia, Célia M

    2016-01-15

    Members of the genus Aeromonas are recognized carriers of antibiotic resistance in aquatic environments. However, their importance on the spread of resistance from hospital effluents to the environment is poorly understood. Quinolone resistant Aeromonas spp. (n = 112) isolated from hospital effluent (HE) and from raw (RWW) and treated wastewater (TWW) of the receiving urban wastewater treatment plant (UWTP) were characterized. Species identification and genetic intraspecies diversity were assessed based on the 16S rRNA, cpn60 and gyrB genes sequence analysis. The antibiotic resistance phenotypes and genotypes (qnrA, qnrB, qnrC, qnrD, qnrS, qnrVC; qepA; oqxAB; aac(6′)-Ib-cr; blaOXA; incU) were analyzed in function of the origin and taxonomic group. Most isolates belonged to the species Aeromonas caviae and Aeromonas hydrophila (50% and 41%, respectively). The quinolone and the beta-lactamase resistance genes aac(6′)-Ib-cr and blaOXA, including gene blaOXA-101, identified for the first time in Aeromonas spp., were detected in 58% and 56% of the isolates, respectively, with identical prevalence in HE and UWTP wastewater. In contrast, the gene qnrS2 was observed mainly in isolates from the UWTP (51%) and rarely in HE isolates (3%), suggesting that its origin is not the clinical setting. Bacterial groups and genes that allow the identification of major routes of antibiotic resistance dissemination are valuable tools to control this problem. In this study, it was concluded that members of the genus Aeromonas harboring the genes aac(6′)-Ib-cr and blaOXA are relevant tracers of antibiotic resistance dissemination in wastewater habitats, while those yielding the gene qnrS2 allow the traceability from non-clinical sources.

  19. The tumor microenvironment underlies acquired resistance to CSF-1R inhibition in gliomas.

    PubMed

    Quail, Daniela F; Bowman, Robert L; Akkari, Leila; Quick, Marsha L; Schuhmacher, Alberto J; Huse, Jason T; Holland, Eric C; Sutton, James C; Joyce, Johanna A

    2016-05-20

    Macrophages accumulate with glioblastoma multiforme (GBM) progression and can be targeted via inhibition of colony-stimulating factor-1 receptor (CSF-1R) to regress high-grade tumors in animal models of this cancer. However, whether and how resistance emerges in response to sustained CSF-1R blockade is unknown. We show that although overall survival is significantly prolonged, tumors recur in >50% of mice. Gliomas reestablish sensitivity to CSF-1R inhibition upon transplantation, indicating that resistance is tumor microenvironment-driven. Phosphatidylinositol 3-kinase (PI3K) pathway activity was elevated in recurrent GBM, driven by macrophage-derived insulin-like growth factor-1 (IGF-1) and tumor cell IGF-1 receptor (IGF-1R). Combining IGF-1R or PI3K blockade with CSF-1R inhibition in recurrent tumors significantly prolonged overall survival. Our findings thus reveal a potential therapeutic approach for treating resistance to CSF-1R inhibitors. PMID:27199435

  20. Acquired resistance mechanisms to tyrosine kinase inhibitors in lung cancer with activating epidermal growth factor receptor mutation--diversity, ductility, and destiny.

    PubMed

    Suda, Kenichi; Mizuuchi, Hiroshi; Maehara, Yoshihiko; Mitsudomi, Tetsuya

    2012-12-01

    Lung cancers that harbor somatic activating mutations in the gene for the epidermal growth factor receptor (EGFR) depend on mutant EGFR for their proliferation and survival; therefore, lung cancer patients with EGFR mutations often dramatically respond to orally available EGFR tyrosine kinase inhibitors (TKIs). However, emergence of acquired resistance is virtually inevitable, thus limiting improvement in patient outcomes. To elucidate and overcome this acquired resistance, multidisciplinary basic and clinical investigational approaches have been applied, using in vitro cell line models or samples obtained from lung cancer patients treated with EGFR-TKIs. These efforts have revealed several acquired resistance mechanisms and candidates, including EGFR secondary mutations (T790M and other rare mutations), MET amplification, PTEN downregulation, CRKL amplification, high-level HGF expression, FAS-NFκB pathway activation, epithelial-mesenchymal transition, and conversion to small cell lung cancer. Interestingly, cancer cells harbor potential destiny and ductility together in acquiring resistance to EGFR-TKIs, as shown in in vitro acquired resistance models. Molecular mechanisms of "reversible EGFR-TKI tolerance" that occur in early phase EGFR-TKI exposure have been identified in cell line models. Furthermore, others have reported molecular markers that can predict response to EGFR-TKIs in clinical settings. Deeper understanding of acquired resistance mechanisms to EGFR-TKIs, followed by the development of molecular target drugs that can overcome the resistance, might turn this fatal disease into a chronic disorder.

  1. Protein arginine methyltransferase 1 may be involved in pregnane x receptor-activated overexpression of multidrug resistance 1 gene during acquired multidrug resistant

    PubMed Central

    Li, Tingting; Kong, Ah-Ng Tony; Ma, Zhiqiang; Liu, Haiyan; Liu, Pinghua; Xiao, Yu; Jiang, Xuehua; Wang, Ling

    2016-01-01

    Purpose Pregnane x receptor (PXR) - activated overexpression of the multidrug resistance 1 (MDR1) gene is an important way for tumor cells to acquire drug resistance. However, the detailed mechanism still remains unclear. In the present study, we aimed to investigate whether protein arginine methyl transferase 1(PRMT1) is involved in PXR - activated overexpression of MDR1 during acquired multidrug resistant. Experimental Design Arginine methyltransferase inhibitor 1 (AMI-1) was used to pharmacologically block PRMT1 in resistant breast cancer cells (MCF7/adr). The mRNA and protein levels of MDR1 were detected by real-time PCR and western blotting analysis. Immunofluorescence microscopy and co-immunoprecipitation were used to investigate the physical interaction between PXR and PRMT1. Then, 136 candidate compounds were screened for PRMT1 inhibitors. Lastly, luciferase reporter gene and nude mice bearing resistant breast cancer xenografts were adopted to investigate the anti-tumor effect of PRMT1 inhibitors when combined with adriamycin. Results AMI-1 significantly suppressed the expression of MDR1 in MCF7/adr cells and increased cells sensitivity of MCF7/adr to adriamycin. Physical interaction between PRMT1 and PXR exists in MCF7/adr cells, which could be disrupted by AMI-1. Those results suggest that PRMT1 may be involved in PXR-activated overexpression of MDR1 in resistant breast cancer cells, and AMI-1 may suppress MDR1 by disrupting the interaction between PRMT1 and PXR. Then, five compounds including rutin, isoquercitrin, salvianolic acid A, naproxen, and felodipline were identified to be PRMT1 inhibitors. Finally, those PRMT1 inhibitors were observed to significantly decrease MDR1 promoter activity in vitro and enhance the antitumor effect of adriamycin in nude mice that bearing resistant breast cancer xenografts. Conclusions PRMT1 may be an important co-activator of PXR in activating MDR1 gene during acquired resistance, and PRMT1 inhibitor combined with

  2. Ductus arteriosus aneurysm with community-acquired methicillin-resistant Staphylococcus aureus infection and spontaneous rupture: a potentially fatal quandary.

    PubMed

    Stewart, Audra; Dyamenahalli, Umesh; Greenberg, S Bruce; Drummond-Webb, Jonathan

    2006-06-01

    We present the case of a 6-month-old previously healthy girl who presented with high fever, labored breathing, and an enlarged cardiac silhouette on her chest radiograph. Comprehensive evaluation discovered a ductus arteriosus aneurysm and pericardial effusion with methicillin-resistant Staphylococcus aureus bacteremia. Despite pericardiocentesis and appropriate intravenous antibiotics, there was rapid enlargement of the aneurysm and accumulation of echogenic material within the ductus arteriosus aneurysm. Infected aneurysm rupture was identified during emergency surgery. This infant also had vocal cord paresis, a likely complication of the surgery. The clinical course, diagnosis, and treatment of this patient are discussed. Infection of a ductus arteriosus or an infected ductal arteriosus aneurysm is a rare and potentially fatal clinical entity. In the era of increasing community-acquired methicillin-resistant S aureus infections, this is a diagnosis that requires a high index of suspicion.

  3. ABCG2 gene amplification and expression in esophageal cancer cells with acquired adriamycin resistance.

    PubMed

    Liu, Liang; Zuo, Lian Fu; Guo, Jian Wen

    2014-04-01

    Resistance to chemotherapeutic agents is the main reason for treatment failure in patients with cancer. The primary mechanism of multidrug resistance (MDR) is the overexpression of drug efflux transporters, including ATP‑binding cassette transporter G2 (ABCG2). To the best of our knowledge, the MDR mechanisms of esophageal cancer have not been described. An adriamycin (ADM)-resistant subline, Eca109/ADM, was generated from the Eca109 esophageal cancer cell line by a stepwise selection in ADM from 0.002 to 0.02 ng/µl. The resulting subline, designated Eca109/ADM, revealed a 3.29-fold resistance against ADM compared with the Eca109 cell line. The ABCG2 gene expression in the Eca109/ADM cells was increased compared with that of the Eca109 cells. The cellular properties of the Eca109/ADM cells were detected by reverse transcription polymerase chain reaction (RT-PCR), flow cytometry and western blotting. The ABCG2 expression levels were detected by RT-PCR and flow cytometry, and the drug efflux effect was detected by flow cytometry. The present study detected the correlation between ABCG2 and the multidrug resistance of esophageal cancer. ABCG2 gene expression and the drug efflux effect of the Eca109/ADM cells were increased compared with those of the Eca109 cells. Collectively, the results of this study indicated that the overexpression of ABCG2 in the Eca109/ADM cells resulted in drug efflux, which may be responsible for the development of esophageal cancer MDR.

  4. Pharmacogenomic approach for the identification of novel determinants of acquired resistance to oxaliplatin in colorectal cancer.

    PubMed

    Martinez-Cardús, Anna; Martinez-Balibrea, Eva; Bandrés, Eva; Malumbres, Raquel; Ginés, Alba; Manzano, José Luís; Taron, Miquel; Garcia-Foncillas, Jesús; Abad, Albert

    2009-01-01

    Oxaliplatin is a third-generation platinum agent used in colorectal cancer treatment. Oxaliplatin resistance acquisition is a complex process mainly based on alteration of genes and pathways involved in its mechanism of action. Therefore, our purpose was to perform a gene expression screening in an in vitro model to identify genes that could play a role in oxaliplatin resistance acquisition processes. Four colorectal cancer cell lines and their oxaliplatin-resistant derived sublines were compared. Microarray analysis was done using Human 19K Oligo Array Slides. RNA from cells were hybridized with a commercial RNA reference sample and labeled with both fluorochromes Cy3 and Cy5. Data were analyzed by hierarchical clustering method. Subsequently, quantitative real-time PCR (qRT-PCR) was used to corroborate microarray data, considering as positively validated those genes that showed significant differences in expression levels between groups and a correlation between microarray and qRT-PCR data. By microarray analysis, 32 candidate genes were identified. After validation process by qRT-PCR, the genes AKT1, CDK5, TRIP, GARP, RGS11, and UGCGL1 were positively validated. The 3 first genes proved to be involved in regulation of nuclear factor-kappabeta antiapoptotic transcription factor previously related to drug resistance, and the other 3 genes are novel finds. We have identified 6 genes related to oxaliplatin resistance acquisition. These findings are of paramount importance to understand these processes better and open new lines of study to elucidate the relevance of this pharmacogenomic approach into the clinic.

  5. A novel acquired ALK F1245C mutation confers resistance to crizotinib in ALK-positive NSCLC but is sensitive to ceritinib.

    PubMed

    Kodityal, Sandeep; Elvin, Julia A; Squillace, Rachel; Agarwal, Nikita; Miller, Vincent A; Ali, Siraj M; Klempner, Samuel J; Ou, Sai-Hong Ignatius

    2016-02-01

    The emergence of acquired anaplastic lymphoma kinase (ALK) resistant mutations is a common molecular mechanism underpinning disease progression during crizotinib treatment of ALK-positive (ALK+) non-small cell lung cancer (NSCLC) patients. Identifying acquired resistance mutations in ALK is paramount for tailoring future therapy with second generation ALK inhibitors and beyond. Comprehensive genomic profiling using hybrid-capture next generation sequencing has been successful in identifying acquired ALK resistance mutations. Here we described the emergence of an ALK F1245C mutation in an advanced ALK+ NSCLC patient (EML4-ALK variant 3a/b) who developed slow disease progression after a durable response to crizotinib. The patient was eventually switched to ceritinib with on-going clinical response. This is the first patient report that ALK F1245C is an acquired resistance mutation to crizotinib that can be overcome by ceritinib. PMID:26775591

  6. Acquired Activated Protein C Resistance, Thrombophilia and Adverse Pregnancy Outcomes: A Study Performed in an Irish Cohort of Pregnant Women

    PubMed Central

    Sedano-Balbás, Sara; Lyons, Mark; Cleary, Brendan; Murray, Margaret; Gaffney, Geraldine; Maher, Majella

    2011-01-01

    The combination of thrombophilia and pregnancy increases the risk of thrombosis and the potential for adverse outcomes during pregnancy. The most significant common inherited risk factor for thrombophilia is activated protein C resistance (APCR), a poor anticoagulant response of APC in haemostasis, which is mainly caused by an inherited single-nucleotide polymorphism (SNP), factor V G1691A (FV Leiden) (FVL), referred as inherited APCR. Changes in the levels of coagulation factors: FV, FVIII, and FIX, and anticoagulant factors: protein S (PS) and protein C (PC) can alter APC function causing acquired APCR. Prothrombin G20210A and methylenetetrahydrofolate reductase (MTHFR) C677T are prothrombotic SNPs which in association with APCR can also increase the risk of thrombosis amongst Caucasians. In this study, a correlation between an acquired APCR phenotype and increased levels of factors V, VIII, and IX was demonstrated. Thrombophilic mutations amongst our acquired APCR pregnant women cohort are relatively common but do not appear to exert a severe undue adverse effect on pregnancy. PMID:21869933

  7. In Vitro Activity of ASP2397 against Aspergillus Isolates with or without Acquired Azole Resistance Mechanisms

    PubMed Central

    Jensen, Rasmus Hare; Cuenca-Estrella, Manuel

    2015-01-01

    ASP2397 is a new compound with a novel and as-yet-unknown target different from that of licensed antifungal agents. It has activity against Aspergillus and Candida glabrata. We compared its in vitro activity against wild-type and azole-resistant A. fumigatus and A. terreus isolates with that of amphotericin B, itraconazole, posaconazole, and voriconazole. Thirty-four isolates, including 4 wild-type A. fumigatus isolates, 24 A. fumigatus isolates with alterations in CYP51A TR/L98H (5 isolates), M220 (9 isolates), G54 (9 isolates), and HapE (1 isolate), and A. terreus isolates (2 wild-type isolates and 1 isolate with an M217I CYP51A alteration), were analyzed. EUCAST E.Def 9.2 and CLSI M38-A2 MIC susceptibility testing was performed. ASP2397 MIC50 values (in milligrams per liter, with MIC ranges in parentheses) determined by EUCAST and CLSI were 0.5 (0.25 to 1) and 0.25 (0.06 to 0.25) against A. fumigatus CYP51A wild-type isolates and were similarly 0.5 (0.125 to >4) and 0.125 (0.06 to >4) against azole-resistant A. fumigatus isolates, respectively. These values were comparable to those for amphotericin B, which were 0.25 (0.125 to 0.5) and 0.25 (0.125 to 0.25) against wild-type isolates and 0.25 (0.125 to 1) and 0.25 (0.125 to 1) against isolates with azole resistance mechanisms, respectively. In contrast, MICs for the azole compounds were elevated and highest for itraconazole: >4 (1 to >4) and 4 (0.5 to >4) against isolates with azole resistance mechanisms compared to 0.125 (0.125 to 0.25) and 0.125 (0.06 to 0.25) against wild-type isolates, respectively. ASP2397 was active against A. terreus CYP51A wild-type isolates (MIC 0.5 to 1), whereas MICs of both azole and ASP2397 were elevated for the mutant isolate. ASP2397 displayed in vitro activity against A. fumigatus and A. terreus isolates which was independent of the presence or absence of azole target gene resistance mutations in A. fumigatus. The findings are promising at a time when azole-resistant A. fumigatus

  8. In Vitro Activity of ASP2397 against Aspergillus Isolates with or without Acquired Azole Resistance Mechanisms.

    PubMed

    Arendrup, Maiken Cavling; Jensen, Rasmus Hare; Cuenca-Estrella, Manuel

    2016-01-01

    ASP2397 is a new compound with a novel and as-yet-unknown target different from that of licensed antifungal agents. It has activity against Aspergillus and Candida glabrata. We compared its in vitro activity against wild-type and azole-resistant A. fumigatus and A. terreus isolates with that of amphotericin B, itraconazole, posaconazole, and voriconazole. Thirty-four isolates, including 4 wild-type A. fumigatus isolates, 24 A. fumigatus isolates with alterations in CYP51A TR/L98H (5 isolates), M220 (9 isolates), G54 (9 isolates), and HapE (1 isolate), and A. terreus isolates (2 wild-type isolates and 1 isolate with an M217I CYP51A alteration), were analyzed. EUCAST E.Def 9.2 and CLSI M38-A2 MIC susceptibility testing was performed. ASP2397 MIC50 values (in milligrams per liter, with MIC ranges in parentheses) determined by EUCAST and CLSI were 0.5 (0.25 to 1) and 0.25 (0.06 to 0.25) against A. fumigatus CYP51A wild-type isolates and were similarly 0.5 (0.125 to >4) and 0.125 (0.06 to >4) against azole-resistant A. fumigatus isolates, respectively. These values were comparable to those for amphotericin B, which were 0.25 (0.125 to 0.5) and 0.25 (0.125 to 0.25) against wild-type isolates and 0.25 (0.125 to 1) and 0.25 (0.125 to 1) against isolates with azole resistance mechanisms, respectively. In contrast, MICs for the azole compounds were elevated and highest for itraconazole: >4 (1 to >4) and 4 (0.5 to >4) against isolates with azole resistance mechanisms compared to 0.125 (0.125 to 0.25) and 0.125 (0.06 to 0.25) against wild-type isolates, respectively. ASP2397 was active against A. terreus CYP51A wild-type isolates (MIC 0.5 to 1), whereas MICs of both azole and ASP2397 were elevated for the mutant isolate. ASP2397 displayed in vitro activity against A. fumigatus and A. terreus isolates which was independent of the presence or absence of azole target gene resistance mutations in A. fumigatus. The findings are promising at a time when azole-resistant A. fumigatus

  9. In Vitro Activity of ASP2397 against Aspergillus Isolates with or without Acquired Azole Resistance Mechanisms.

    PubMed

    Arendrup, Maiken Cavling; Jensen, Rasmus Hare; Cuenca-Estrella, Manuel

    2015-11-09

    ASP2397 is a new compound with a novel and as-yet-unknown target different from that of licensed antifungal agents. It has activity against Aspergillus and Candida glabrata. We compared its in vitro activity against wild-type and azole-resistant A. fumigatus and A. terreus isolates with that of amphotericin B, itraconazole, posaconazole, and voriconazole. Thirty-four isolates, including 4 wild-type A. fumigatus isolates, 24 A. fumigatus isolates with alterations in CYP51A TR/L98H (5 isolates), M220 (9 isolates), G54 (9 isolates), and HapE (1 isolate), and A. terreus isolates (2 wild-type isolates and 1 isolate with an M217I CYP51A alteration), were analyzed. EUCAST E.Def 9.2 and CLSI M38-A2 MIC susceptibility testing was performed. ASP2397 MIC50 values (in milligrams per liter, with MIC ranges in parentheses) determined by EUCAST and CLSI were 0.5 (0.25 to 1) and 0.25 (0.06 to 0.25) against A. fumigatus CYP51A wild-type isolates and were similarly 0.5 (0.125 to >4) and 0.125 (0.06 to >4) against azole-resistant A. fumigatus isolates, respectively. These values were comparable to those for amphotericin B, which were 0.25 (0.125 to 0.5) and 0.25 (0.125 to 0.25) against wild-type isolates and 0.25 (0.125 to 1) and 0.25 (0.125 to 1) against isolates with azole resistance mechanisms, respectively. In contrast, MICs for the azole compounds were elevated and highest for itraconazole: >4 (1 to >4) and 4 (0.5 to >4) against isolates with azole resistance mechanisms compared to 0.125 (0.125 to 0.25) and 0.125 (0.06 to 0.25) against wild-type isolates, respectively. ASP2397 was active against A. terreus CYP51A wild-type isolates (MIC 0.5 to 1), whereas MICs of both azole and ASP2397 were elevated for the mutant isolate. ASP2397 displayed in vitro activity against A. fumigatus and A. terreus isolates which was independent of the presence or absence of azole target gene resistance mutations in A. fumigatus. The findings are promising at a time when azole-resistant A. fumigatus

  10. Erlotinib promotes endoplasmic reticulum stress-mediated injury in the intestinal epithelium

    SciTech Connect

    Fan, Lu; Hu, Lingna; Yang, Baofang; Fang, Xianying; Gao, Zhe; Li, Wanshuai; Sun, Yang; Shen, Yan; Wu, Xuefeng; Shu, Yongqian; Gu, Yanhong; Wu, Xudong; Xu, Qiang

    2014-07-01

    Erlotinib, a popular drug for treating non-small cell lung cancer (NSCLC), causes diarrhea in approximately 55% of patients receiving this drug. In the present study, we found that erlotinib induced barrier dysfunction in rat small intestine epithelial cells (IEC-6) by increasing epithelial permeability and down-regulating E-cadherin. The mRNA levels of various pro-inflammatory cytokines (Il-6, Il-25 and Il-17f) were increased after erlotinib treatment in IEC-6 cells. Erlotinib concentration- and time-dependently induced apoptosis and endoplasmic reticulum (ER) stress in both IEC-6 and human colon epithelial cells (CCD 841 CoN). Intestinal epithelial injury was also observed in male C57BL/6J mice administrated with erlotinib. Knockdown of C/EBP homologous protein (CHOP) with small interference RNA partially reversed erlotinib-induced apoptosis, production of IL-6 and down-regulation of E-cadherin in cultured intestinal epithelial cells. In conclusion, erlotinib caused ER stress-mediated injury in the intestinal epithelium, contributing to its side effects of diarrhea in patients. - Highlights: • Erlotinib destroyed barrier integrity both in vitro and in vivo. • Erlotinib induced inflammation both in vitro and in vivo. • Erlotinib induced apoptosis both in vitro and in vivo. • ER stress contributed to erlotinib-induced barrier dysfunction.

  11. Fluoroquinolone susceptibility testing of Salmonella enterica: detection of acquired resistance and selection of zone diameter breakpoints for levofloxacin and ofloxacin.

    PubMed

    Sjölund-Karlsson, Maria; Howie, Rebecca L; Crump, John A; Whichard, Jean M

    2014-03-01

    Fluoroquinolones (e.g., ciprofloxacin) have become a mainstay for treating severe Salmonella infections in adults. Fluoroquinolone resistance in Salmonella is mostly due to mutations in the topoisomerase genes, but plasmid-mediated quinolone resistance (PMQR) mechanisms have also been described. In 2012, the Clinical and Laboratory Standards Institute (CLSI) revised the ciprofloxacin interpretive criteria (breakpoints) for disk diffusion and MIC test methods for Salmonella. In 2013, the CLSI published MIC breakpoints for Salmonella to levofloxacin and ofloxacin, but breakpoints for assigning disk diffusion results to susceptible (S), intermediate (I), and resistant (R) categories are still needed. In this study, the MICs and inhibition zone diameters for nalidixic acid, ciprofloxacin, levofloxacin, and ofloxacin were determined for 100 clinical isolates of nontyphi Salmonella with or without resistance mechanisms. We confirmed that the new levofloxacin MIC breakpoints resulted in the highest category agreement (94%) when plotted against the ciprofloxacin MICs and that the new ofloxacin MIC breakpoints resulted in 92% category agreement between ofloxacin and ciprofloxacin. By applying the new MIC breakpoints in the MIC zone scattergrams for levofloxacin and ofloxacin, the following disk diffusion breakpoints generated the least number of errors: ≥28 mm (S), 19 to 27 mm (I), and ≤18 mm (R) for levofloxacin and ≥25 mm (S), 16 to 24 mm (I), and ≤15 mm (R) for ofloxacin. Neither the levofloxacin nor the ofloxacin disk yielded good separation of isolates with and without resistance mechanisms. Further studies will be needed to develop a disk diffusion assay that efficiently detects all isolates with acquired resistance to fluoroquinolones.

  12. Case Report: Metabolic Profiling Identifies Lung Tumor Responsiveness to Erlotinib

    PubMed Central

    Fan, Teresa W-M; Lane, Andrew N; Higashi, Richard M; Bousamra, Michael; Kloecker, Goetz; Miller, Donald M.

    2009-01-01

    A subtype of non-small cell lung cancer, bronchioalveolar adenocarcinoma (BAC), is more prevalent in Asian female non-smokers, and is more likely to respond to treatment with tyrosine kinase inhibitors such as erlotinib and gefitinib. Nuclear magnetic resonance and mass spectrometry-based metabolomic analysis of extracts from two different lung lesions and surrounding non-cancerous tissues of a BAC patient showed novel protein and phospholipid-associated metabolic differences that correlated with tumor development as well as PET and erlotinib sensitivity. PMID:19409891

  13. Metabolic profiling identifies lung tumor responsiveness to erlotinib.

    PubMed

    Fan, Teresa W-M; Lane, Andrew N; Higashi, Richard M; Bousamra, Michael; Kloecker, Goetz; Miller, Donald M

    2009-08-01

    A subtype of non-small cell lung cancer, bronchioalveolar adenocarcinoma (BAC), is more prevalent in Asian female non-smokers, and is more likely to respond to treatment with tyrosine kinase inhibitors such as erlotinib and gefitinib. Nuclear magnetic resonance and mass spectrometry-based metabolomic analysis of extracts from two different lung lesions and surrounding non-cancerous tissues of a BAC patient showed novel protein and phospholipid-associated metabolic differences that correlated with tumor development as well as PET and erlotinib sensitivity.

  14. The phenomenon of acquired resistance to metformin in breast cancer cells: The interaction of growth pathways and estrogen receptor signaling.

    PubMed

    Scherbakov, Alexander M; Sorokin, Danila V; Tatarskiy, Victor V; Prokhorov, Nikolay S; Semina, Svetlana E; Berstein, Lev M; Krasil'nikov, Mikhail A

    2016-04-01

    Metformin, a biguanide antidiabetic drug, is used to decrease hyperglycemia in patients with type 2 diabetes. Recently, the epidemiological studies revealed the potential of metformin as an anti-tumor drug for several types of cancer, including breast cancer. Anti-tumor metformin action was found to be mediated, at least in part, via activation of adenosine monophosphate-activated protein kinase (AMPK)-intracellular energy sensor, which inhibits the mammalian target of rapamycin (mTOR) and some other signaling pathways. Nevertheless, some patients can be non-sensitive or resistant to metformin action. Here we analyzed the mechanism of the formation of metformin-resistant phenotype in breast cancer cells and its role in estrogen receptor (ER) regulation. The experiments were performed on the ER-positive MCF-7 breast cancer cells and metformin-resistant MCF-7 subline (MCF-7/M) developed due to long-term metformin treatment. The transcriptional activity of NF-κB and ER was measured by the luciferase reporter gene analysis. The protein expression was determined by immunoblotting (Snail1, (phospho)AMPK, (phospho)IκBα, (phospho)mTOR, cyclin D1, (phospho)Akt and ERα) and immunohistochemical analysis (E-cadherin). We have found that: 1) metformin treatment of MCF-7 cells is accompanied with the stimulation of AMPK and inhibition of growth-related proteins including IκBα, NF-κB, cyclin D1 and ERα; 2) long-term metformin treatment lead to the appearance and progression of cross-resistance to metformin and tamoxifen; the resistant cells are characterized with the unaffected AMPK activity, but the irreversible ER suppression and constitutive activation of Akt/Snail1 signaling; 3) Akt/Snail1 signaling is involved into progression of metformin resistance. The results presented may be considered as the first evidence of the progression of cross-resistance to metformin and tamoxifen in breast cancer cells. Importantly, the acquired resistance to both drugs is based on the

  15. Estimating Trends in the Proportion of Transmitted and Acquired HIV Drug Resistance in a Long Term Observational Cohort in Germany

    PubMed Central

    Schmidt, Daniel; Kollan, Christian; Fätkenheuer, Gerd; Schülter, Eugen; Stellbrink, Hans-Jürgen; Noah, Christian; Jensen, Björn-Erik Ole; Stoll, Matthias; Bogner, Johannes R.; Eberle, Josef; Meixenberger, Karolin; Kücherer, Claudia; Hamouda, Osamah; Bartmeyer, Barbara

    2014-01-01

    Objective We assessed trends in the proportion of transmitted (TDR) and acquired (ADR) HIV drug resistance and associated mutations between 2001 and 2011 in the German ClinSurv-HIV Drug Resistance Study. Method The German ClinSurv-HIV Drug Resistance Study is a subset of the German ClinSurv-HIV Cohort. For the ClinSurv-HIV Drug Resistance Study all available sequences isolated from patients in five study centres of the long term observational ClinSurv-HIV Cohort were included. TDR was estimated using the first viral sequence of antiretroviral treatment (ART) naïve patients. One HIV sequence/patient/year of ART experienced patients was considered to estimate the proportion of ADR. Trends in the proportion of HIV drug resistance were calculated by logistic regression. Results 9,528 patients were included into the analysis. HIV-sequences of antiretroviral naïve and treatment experienced patients were available from 34% (3,267/9,528) of patients. The proportion of TDR over time was stable at 10.4% (95% CI 9.1–11.8; p for trend = 0.6; 2001–2011). The proportion of ADR among all treated patients was 16%, whereas it was high among those with available HIV genotypic resistance test (64%; 1,310/2,049 sequences; 95% CI 62–66) but declined significantly over time (OR 0.8; 95% CI 0.77–0.83; p for trend<0.001; 2001–2011). Viral load monitoring subsequent to resistance testing was performed in the majority of treated patients (96%) and most of them (67%) were treated successfully. Conclusions The proportion of TDR was stable in this study population. ADR declined significantly over time. This decline might have been influenced by broader resistance testing, resistance test guided therapy and the availability of more therapeutic options and not by a decline in the proportion of TDR within the study population. PMID:25148412

  16. The phenomenon of acquired resistance to metformin in breast cancer cells: The interaction of growth pathways and estrogen receptor signaling.

    PubMed

    Scherbakov, Alexander M; Sorokin, Danila V; Tatarskiy, Victor V; Prokhorov, Nikolay S; Semina, Svetlana E; Berstein, Lev M; Krasil'nikov, Mikhail A

    2016-04-01

    Metformin, a biguanide antidiabetic drug, is used to decrease hyperglycemia in patients with type 2 diabetes. Recently, the epidemiological studies revealed the potential of metformin as an anti-tumor drug for several types of cancer, including breast cancer. Anti-tumor metformin action was found to be mediated, at least in part, via activation of adenosine monophosphate-activated protein kinase (AMPK)-intracellular energy sensor, which inhibits the mammalian target of rapamycin (mTOR) and some other signaling pathways. Nevertheless, some patients can be non-sensitive or resistant to metformin action. Here we analyzed the mechanism of the formation of metformin-resistant phenotype in breast cancer cells and its role in estrogen receptor (ER) regulation. The experiments were performed on the ER-positive MCF-7 breast cancer cells and metformin-resistant MCF-7 subline (MCF-7/M) developed due to long-term metformin treatment. The transcriptional activity of NF-κB and ER was measured by the luciferase reporter gene analysis. The protein expression was determined by immunoblotting (Snail1, (phospho)AMPK, (phospho)IκBα, (phospho)mTOR, cyclin D1, (phospho)Akt and ERα) and immunohistochemical analysis (E-cadherin). We have found that: 1) metformin treatment of MCF-7 cells is accompanied with the stimulation of AMPK and inhibition of growth-related proteins including IκBα, NF-κB, cyclin D1 and ERα; 2) long-term metformin treatment lead to the appearance and progression of cross-resistance to metformin and tamoxifen; the resistant cells are characterized with the unaffected AMPK activity, but the irreversible ER suppression and constitutive activation of Akt/Snail1 signaling; 3) Akt/Snail1 signaling is involved into progression of metformin resistance. The results presented may be considered as the first evidence of the progression of cross-resistance to metformin and tamoxifen in breast cancer cells. Importantly, the acquired resistance to both drugs is based on the

  17. Azithromycin Dose To Maximize Efficacy and Suppress Acquired Drug Resistance in Pulmonary Mycobacterium avium Disease

    PubMed Central

    Deshpande, Devyani; Pasipanodya, Jotam G.

    2016-01-01

    Mycobacterium avium complex is now the leading mycobacterial cause of chronic pneumonia in the United States. Macrolides and ethambutol form the backbone of the regimen used in the treatment of pulmonary disease. However, therapy outcomes remain poor, with microbial cure rates of 4% in cavitary disease. The treatment dose of azithromycin has mostly been borrowed from that used to treat other bacterial pneumonias; there are no formal dose-response studies in pulmonary M. avium disease and the optimal dose is unclear. We utilized population pharmacokinetics and pharmacokinetics/pharmacodynamics-derived azithromycin exposures associated with optimal microbial kill or resistance suppression to perform 10,000 patient Monte Carlo simulations of dose effect studies for daily azithromycin doses of 0.5 to 10 g. The currently recommended dose of 500 mg per day achieved the target exposures in 0% of patients. Exposures associated with optimal kill and resistance suppression were achieved in 87 and 54% of patients, respectively, only by the very high dose of 8 g per day. The azithromycin susceptibility breakpoint above which patients failed therapy on the very high doses of 8 g per day was an MIC of 16 mg/liter, suggesting a critical concentration of 32 mg/liter, which is 8-fold lower than the currently used susceptibility breakpoint of 256 mg/liter. If the standard dose of 500 mg a day were used, then the critical concentration would fall to 2 mg/liter, 128-fold lower than 256 mg/liter. The misclassification of resistant isolates as susceptible could explain the high failure rates of current doses. PMID:26810646

  18. Role of major histocompatibility complex class II in resistance of mice to naturally acquired infection with Syphacia obvelata

    NASA Technical Reports Server (NTRS)

    Stewart, Patricia W.; Chapes, Stephen K.

    2003-01-01

    Genetics plays a substantial role in host resistance in many host-parasite interactions. We examined the prevalence of naturally acquired infection with Syphacia obvelata in a number of mouse strains housed in a non-barrier facility. These mice, which included cross-bred and congenic, inbred strains on various genetic backgrounds, differ in the loci for the immune function genes--major histocompatibility complex class II (MHCII), toll-like receptor 4 (Tlr4), and solute carrier family 11, member 1 (Slc11a1)--which allowed comparisons of the impact of these genes on resistance to pinworm infection. Male and female mice of various ages were sampled over an 18-month period; infection was determined by use of the cellophane tape test. Results indicated that mice that were MHCII+/+ had a significantly lower prevalence of infection than did mice that were MHCII-/-. Differences were not seen between male and female mice. Although MHCII+/+ mice had an age-associated decrease in infection prevalence, such decrease was not seen in MHCII-/- mice. In contrast, infection prevalence in mice with the normal Tlr4 gene (Tlr4(LPS-n/LPS-n)) gene did not differ significantly compared with that in mice that were homozygous for either the point mutation (Tlr4(LPS-d/LPS-d)) or deletion (Tlr4(LPS-del/LPS-del)) of that gene. Likewise, the presence (Sle11a1r/r) or absence (Slc11a1s/s) of functional alleles for Slc11a1 had no effect on the prevalence of infection with S. obvelata. In conclusion, presence of MHCII, but not Tlr4 or Slc11a1 significantly influences prevalence of naturally acquired infection with S. obvelata. These data justify further comprehensive analyses of the immune components that are involved in pinworm resistance.

  19. Acquired resistance to innate immune clearance promotes Klebsiella pneumoniae ST258 pulmonary infection

    PubMed Central

    Ahn, Danielle; Peñaloza, Hernán; Wang, Zheng; Wickersham, Matthew; Parker, Dane; Patel, Purvi; Koller, Antonius; Chen, Emily I.; Bueno, Susan M.; Uhlemann, Anne-Catrin; Prince, Alice

    2016-01-01

    Adaptive changes in the genome of a locally predominant clinical isolate of the multidrug-resistant Klebsiella pneumoniae ST258 (KP35) were identified and help to explain the selection of this strain as a successful pulmonary pathogen. The acquisition of 4 new ortholog groups, including an arginine transporter, enabled KP35 to outcompete related ST258 strains lacking these genes. KP35 infection elicited a monocytic response, dominated by Ly6Chi monocytic myeloid-derived suppressor cells that lacked phagocytic capabilities, expressed IL-10, arginase, and antiinflammatory surface markers. In comparison with other K. pneumoniae strains, KP35 induced global changes in the phagocytic response identified with proteomics, including evasion of Ca2+ and calpain activation necessary for phagocytic killing, confirmed in functional studies with neutrophils. This comprehensive analysis of an ST258 K. pneumoniae isolate reveals ongoing genetic adaptation to host microenvironments and innate immune clearance mechanisms that complements its repertoire of antimicrobial resistance genes and facilitates persistence in the lung. PMID:27777978

  20. Electric stimulations mediated beta lactam resistance reversal and correlation with growth dynamics of community acquired methicillin resistant Staphylococcus aureus.

    PubMed

    Kainthola, Anup; Uniyal, Akshat; Srivastava, Nidhi; Bhatt, Ajay B

    2015-08-01

    The community associated methicillin resistant Staphylococcus aureus (CA-MRSA) is a serious issue of public health. Here, we conducted an experimental approach to determine: (i) the optimal significant stimulation range of electrical current for effective checking of CA-MRSA growth; (ii) the effect of electrical stimulations on methicillin susceptibility and possible beta lactam resistance reversal; and (iii) the variation in the level of ATP as function of exposure to electric current. An 8 chambered electrical system was developed for DC flow in control and test sets, with and without drug (oxacillin 4 mg/ml). Measurement of growth by CFU/ml and spectrometry, susceptibility and ATP levels were calculated and interpreted. Linear pattern in reduction of ATP was observed with respect to the intensity of electric current (EC) and an enhanced inhibitory effect was explicit with 1000 microampere (μA) with 30 min exposure. At 4000 μA exposure to DC at 180 min and in combination of drug (μA+D), the growth of CA-MRSA was substantially checked to 0.23 absorbance in comparison to current without drug and the effect of DC electrical current to the culture showed that 10 μA, 100 μA and 4000 μA current exposure in combination of oxacillin (μA+D), markedly reduced the CFU to an average of 256.4. ATP level was linearly reduced with exposure to EC.

  1. Genomic and Molecular Characterization of Miltefosine Resistance in Leishmania infantum Strains with Either Natural or Acquired Resistance through Experimental Selection of Intracellular Amastigotes

    PubMed Central

    Hendrickx, Sarah; Eberhardt, Eline; Garcia-Hernandez, Raquel; Lachaud, Laurence; Cotton, James; Sanders, Mandy; Cuypers, Bart; Imamura, Hideo; Dujardin, Jean-Claude; Delputte, Peter; Cos, Paul; Caljon, Guy; Gamarro, Francisco; Castanys, Santiago

    2016-01-01

    During the last decade miltefosine (MIL) has been used as first-line treatment for visceral leishmaniasis in endemic areas with antimonial resistance, but a decline in clinical effectiveness is now being reported. While only two MIL-resistant Leishmania infantum strains from HIV co-infected patients have been documented, phenotypic MIL-resistance for L. donovani has not yet been identified in the laboratory. Hence, a better understanding of the factors contributing to increased MIL-treatment failure is necessary. Given the paucity of defined MIL-resistant L. donovani clinical isolates, this study used an experimental amastigote-selected MIL-resistant L. infantum isolate (LEM3323). In-depth exploration of the MIL-resistant phenotype was performed by coupling genomic with phenotypic data to gain insight into gene function and the mutant phenotype. A naturally MIL-resistant L. infantum clinical isolate (LEM5159) was included to compare both datasets. Phenotypically, resistance was evaluated by determining intracellular amastigote susceptibility in vitro and actual MIL-uptake. Genomic analysis provided supportive evidence that the resistance selection model on intracellular amastigotes can be a good proxy for the in vivo field situation since both resistant strains showed mutations in the same inward transporter system responsible for the acquired MIL-resistant phenotype. In line with previous literature findings in promastigotes, our data confirm a defective import machinery through inactivation of the LiMT/LiRos3 protein complex as the main mechanism for MIL-resistance also in intracellular amastigotes. Whole genome sequencing analysis of LEM3323 revealed a 2 base pair deletion in the LiMT gene that led to the formation an early stop codon and a truncation of the LiMT protein. Interestingly, LEM5159 revealed mutations in both the LiMT and LiRos3 genes, resulting in an aberrant expression of the LiMT protein. To verify that these mutations were indeed accountable for

  2. Genomic and Molecular Characterization of Miltefosine Resistance in Leishmania infantum Strains with Either Natural or Acquired Resistance through Experimental Selection of Intracellular Amastigotes.

    PubMed

    Mondelaers, Annelies; Sanchez-Cañete, Maria P; Hendrickx, Sarah; Eberhardt, Eline; Garcia-Hernandez, Raquel; Lachaud, Laurence; Cotton, James; Sanders, Mandy; Cuypers, Bart; Imamura, Hideo; Dujardin, Jean-Claude; Delputte, Peter; Cos, Paul; Caljon, Guy; Gamarro, Francisco; Castanys, Santiago; Maes, Louis

    2016-01-01

    During the last decade miltefosine (MIL) has been used as first-line treatment for visceral leishmaniasis in endemic areas with antimonial resistance, but a decline in clinical effectiveness is now being reported. While only two MIL-resistant Leishmania infantum strains from HIV co-infected patients have been documented, phenotypic MIL-resistance for L. donovani has not yet been identified in the laboratory. Hence, a better understanding of the factors contributing to increased MIL-treatment failure is necessary. Given the paucity of defined MIL-resistant L. donovani clinical isolates, this study used an experimental amastigote-selected MIL-resistant L. infantum isolate (LEM3323). In-depth exploration of the MIL-resistant phenotype was performed by coupling genomic with phenotypic data to gain insight into gene function and the mutant phenotype. A naturally MIL-resistant L. infantum clinical isolate (LEM5159) was included to compare both datasets. Phenotypically, resistance was evaluated by determining intracellular amastigote susceptibility in vitro and actual MIL-uptake. Genomic analysis provided supportive evidence that the resistance selection model on intracellular amastigotes can be a good proxy for the in vivo field situation since both resistant strains showed mutations in the same inward transporter system responsible for the acquired MIL-resistant phenotype. In line with previous literature findings in promastigotes, our data confirm a defective import machinery through inactivation of the LiMT/LiRos3 protein complex as the main mechanism for MIL-resistance also in intracellular amastigotes. Whole genome sequencing analysis of LEM3323 revealed a 2 base pair deletion in the LiMT gene that led to the formation an early stop codon and a truncation of the LiMT protein. Interestingly, LEM5159 revealed mutations in both the LiMT and LiRos3 genes, resulting in an aberrant expression of the LiMT protein. To verify that these mutations were indeed accountable for

  3. Acquiring transgenic tobacco plants with insect resistance and glyphosate tolerance by fusion gene transformation.

    PubMed

    Sun, He; Lang, Zhihong; Zhu, Li; Huang, Dafang

    2012-10-01

    The advantages of gene 'stacking' or 'pyramiding' are obvious in genetically modified (GM) crops, and several different multi-transgene-stacking methods are available. Using linker peptides for multiple gene transformation is considered to be a good method to meet a variety of needs. In our experiment, the Bt cry1Ah gene, which encodes the insect-resistance protein, and the mG ( 2 ) -epsps gene, which encodes the glyphosate-tolerance protein, were connected by a 2A or LP4/2A linker. Linker 2A is a peptide from the foot-and-mouth disease virus (FMDV) that has self-cleavage activity. LP4 is a peptide from Raphanus sativus seeds that has a recognition site and is cleaved by a protease. LP4/2A is a hybrid peptide that contains the first 9 amino acids of LP4 and 20 amino acids from 2A. We used the linker peptide to construct four coordinated expression vectors: pHAG, pHLAG, pGAH and pGLAH. Two single gene expression vectors, pSAh and pSmG(2), were used as controls. The six expression vectors and the pCAMBIA2301 vector were transferred into tobacco by Agrobacterium tumefaciens-mediated transformation, and 529 transformants were obtained. Molecular detection and bioassay detection data demonstrated that the transgenic tobaccos possessed good pest resistance and glyphosate tolerance. The two genes in the fusion vector were expressed simultaneously. The plants with the genes linked by the LP4/2A peptide showed better pest resistance and glyphosate tolerance than the plants with the genes linked by 2A. The expression level of the two genes linked by LP4/2A was not significantly different from the single gene vector. Key message The expression level of the two genes linked by LP4/2A was higher than those linked by 2A and was not significantly different from the single gene vector.

  4. Multiple myeloma acquires resistance to EGFR inhibitor via induction of pentose phosphate pathway.

    PubMed

    Chen, Yan; Huang, Ruibin; Ding, Jianghua; Ji, Dexiang; Song, Bing; Yuan, Liya; Chang, Hong; Chen, Guoan

    2015-04-20

    Multiple myeloma (MM) was characterized by frequent mutations in KRAS/NRAS/BRAF within the EGFR pathway that could induce resistance to EGFR inhibitors. We here report that EGFR inhibition solely exhibited moderate inhibition in KRAS/NRAS/BRAF wildtype (triple-WT) MM cells, whilst had no effect in myeloma cells with any of the mutated genes. The moderate inhibitory effect was conferred by induction of pentose phosphate pathway (PPP) when cells were treated with Gefitinib, the EGFR inhibitor. Combination of Gefitinib with PPP inhibitor 6AN effected synergistically in triple-WT cells. The inhibition could be restored by addition of NADPH. Dual EGFR/ERBB2 inhibitor Afatinib also exhibited similar effects. Further genetic silencing of EGFR, ERBB2 and mTOR indicated that major effect conferred by ERBB2 was via convergence to EGFR pathway in MM. Our results contributed to the individualized targeted therapy with EGFR inhibitors in MM.

  5. Molecular Characterization of Acquired Enrofloxacin Resistance in Mycoplasma synoviae Field Isolates

    PubMed Central

    Gerchman, I.; Mikula, I.; Gobbo, F.; Catania, S.; Levisohn, S.

    2013-01-01

    The in vitro activity of enrofloxacin against 73 Mycoplasma synoviae field strains isolated in Israel and Europe was determined by broth microdilution. Decreased susceptibility to enrofloxacin was identified in 59% of strains, with the MICs ranging from 1 to >16 μg/ml. The estimated MIC50 and MIC90 values for enrofloxacin were 2 and 8 μg/ml, respectively. Moreover, this study showed that 92% of recent Israeli field isolates (2009 to 2011) of M. synoviae have MICs of ≥2 μg/ml to enrofloxacin. Comparison of the quinolone resistance-determining regions (QRDRs) in M. synoviae isolates revealed a clear correlation between the presence of one of the amino acid substitutions Asp79-Asn, Thr80-Ala/Ile, Ser81-Pro, and Asp84-Asn/Tyr/His of the ParC QRDR and decreased susceptibility to enrofloxacin (MIC, ≥1 μg/ml). Amino acid substitutions at positions GyrA 87, GyrB 401/402, and ParE 420/454 were also identified, but there was no clear-cut correlation with susceptibility to enrofloxacin. Comparison of vlhA molecular profiles revealed the presence of 9 different genotypes in the Israeli M. synoviae field isolates and 10 genotypes in the European isolates; only one vlhA genotype (type 4) was identified in both cohorts. Based on results of vlhA molecular typing, several mechanisms for emergence and dissemination of Israeli enrofloxacin-resistant M. synoviae isolates are suggested. PMID:23612192

  6. Erlotinib: CP 358774, NSC 718781, OSI 774, R 1415.

    PubMed

    2003-01-01

    Erlotinib [Tarceva, R 1415, CP 358774, OSI 774, NSC 718781] is a small molecular, once-a-day, orally active inhibitor of the epidermal growth factor receptor tyrosine kinase. This profile has been selected from R&D Insight, a pharmaceutical intelligence database produced by Adis International Ltd. It is one of a class of anticancer drugs that target the underlying molecular mechanism involving oncogenes and tumour suppressor genes, which play critical roles in the conversion of normal cells into a cancerous state. Erlotinib is undergoing clinical development as an oral tablet by an alliance between OSI Pharmaceuticals, Genentech and Roche. OSI Pharmaceuticals, Genentech and Roche have entered an agreement for the global development and commercialisation of erlotinib. Under the terms of the agreement, Genentech and OSI will share costs and profit-taking for commercialising the product in the US. The overall costs of the development programme will be shared equally between the three companies. OSI will keep certain co-promotion rights in the US and Genentech will be responsible for commercialising the drug in the US should the FDA approve it. Roche will take the responsibility for obtaining regulatory approval and commercialisation in territories outside the US and pay royalties to OSI on net sales of the product in these markets. Initially, the alliance partners intend to pursue development of erlotinib in all the major tumour markets, particularly for non-small cell lung cancer (NSCLC) in which the group will focus on front-line combination approaches. Pfizer and OSI Pharmaceuticals in the US were developing erlotinib as a treatment for solid tumours. However, in June 2000, Pfizer merged with Warner-Lambert. The resulting company retained the Pfizer name, but in order to meet Federal Trade Commission requirements for the merger Pfizer granted all developmental and marketing rights for erlotinib to OSI Pharmaceuticals. This divestiture of the erlotinib portfolio, in

  7. Erlotinib: CP 358774, NSC 718781, OSI 774, R 1415.

    PubMed

    2003-01-01

    Erlotinib [Tarceva, R 1415, CP 358774, OSI 774, NSC 718781] is a small molecular, once-a-day, orally active inhibitor of the epidermal growth factor receptor tyrosine kinase. This profile has been selected from R&D Insight, a pharmaceutical intelligence database produced by Adis International Ltd. It is one of a class of anticancer drugs that target the underlying molecular mechanism involving oncogenes and tumour suppressor genes, which play critical roles in the conversion of normal cells into a cancerous state. Erlotinib is undergoing clinical development as an oral tablet by an alliance between OSI Pharmaceuticals, Genentech and Roche. OSI Pharmaceuticals, Genentech and Roche have entered an agreement for the global development and commercialisation of erlotinib. Under the terms of the agreement, Genentech and OSI will share costs and profit-taking for commercialising the product in the US. The overall costs of the development programme will be shared equally between the three companies. OSI will keep certain co-promotion rights in the US and Genentech will be responsible for commercialising the drug in the US should the FDA approve it. Roche will take the responsibility for obtaining regulatory approval and commercialisation in territories outside the US and pay royalties to OSI on net sales of the product in these markets. Initially, the alliance partners intend to pursue development of erlotinib in all the major tumour markets, particularly for non-small cell lung cancer (NSCLC) in which the group will focus on front-line combination approaches. Pfizer and OSI Pharmaceuticals in the US were developing erlotinib as a treatment for solid tumours. However, in June 2000, Pfizer merged with Warner-Lambert. The resulting company retained the Pfizer name, but in order to meet Federal Trade Commission requirements for the merger Pfizer granted all developmental and marketing rights for erlotinib to OSI Pharmaceuticals. This divestiture of the erlotinib portfolio, in

  8. Erlotinib-induced Rosacea-like Dermatitis.

    PubMed

    Rezaković, Saida; Paštar, Zrinjka; Bukvić Mokos, Zrinka; Pavliša, Gordana; Kovačević, Suzana

    2016-04-01

    Skin and skin adnexa toxicities are the most common side effects associated with epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) and occur in most patients receiving this therapy. The majority of these cutaneous side effects are transient, reversible, and dose dependent. Although these symptoms are in general not severe, they significantly affect quality of life and can have a serious effect on treatment compliance as well as the treatment regimen. The most common early symptoms present as papulopustules on an erythematous base, usually localized in seborrheic areas. This clinical presentation is commonly described as "acneiform", although these adverse reactions have clinical presentations, such as rosacea-like and seborrheic-like dermatitis. In this context, we report a case of a 77-year-old man with a medical history of planocellular lung cancer with ipsilateral pulmonary metastasis and mediastinum infiltration who received erlotinib as a third-line therapy, presenting with centrofacial rosaceiform rash as a side effect associated with the use of EGFR-TKIs. The patient had a negative previous history of rosacea. Therefore, symptoms probably occurred as an adverse reaction due to the oncological therapy. Current terminology of early cutaneous adverse reactions caused by EGFR-TKIs refers to "acneiform" or "papulopustular" lesions, excluding less common side effects such as rosacea-like dermatitis so these symptoms might be overlooked and misdiagnosed. Thus, we would like to emphasize the importance of developing a more accurate classification of terms in order to provide early detection of all possible cutaneous side effects, including less common ones, providing specific and timely treatment, and allowing continuation of drug therapy. PMID:27149133

  9. Acquired resistance to combination treatment through loss of synergy with MEK and PI3K inhibitors in colorectal cancer

    PubMed Central

    Bhattacharya, Bhaskar; Low, Sarah Hong Hui; Chong, Mei Ling; Chia, Dilys; Koh, King Xin; Sapari, Nur Sabrina; Kaye, Stanley; Hung, Huynh; Benoukraf, Touati; Soong, Richie

    2016-01-01

    Historically, understanding of acquired resistance (AQR) to combination treatment has been based on knowledge of resistance to its component agents. To test whether an altered drug interaction could be an additional factor in AQR to combination treatment, models of AQR to combination and single agent MEK and PI3K inhibitor treatment were generated. Combination indices indicated combination treatment of PI3K and MEK inhibitors remained synergistic in cells with AQR to single agent but not combination AQR cells. Differences were also observed between the models in cellular phenotypes, pathway signaling and drug cross-resistance. Genomics implicated TGFB2-EDN1 overexpression as candidate determinants in models of AQR to combination treatment. Supplementation of endothelin in parental cells converted synergism to antagonism. Silencing of TGFB2 or EDN1 in cells with AQR conferred synergy between PI3K and MEK inhibitor. These results highlight that AQR to combination treatment may develop through alternative mechanisms to those of single agent treatment, including a change in drug interaction. PMID:27081080

  10. CYP3A5 mediates basal and acquired therapy resistance in different subtypes of pancreatic ductal adenocarcinoma

    PubMed Central

    Noll, Elisa M.; Eisen, Christian; Stenzinger, Albrecht; Espinet, Elisa; Muckenhuber, Alexander; Klein, Corinna; Vogel, Vanessa; Klaus, Bernd; Nadler, Wiebke; Rösli, Christoph; Lutz, Christian; Kulke, Michael; Engelhardt, Jan; Zickgraf, Franziska M.; Espinosa, Octavio; Schlesner, Matthias; Jiang, Xiaoqi; Kopp-Schneider, Annette; Neuhaus, Peter; Bahra, Marcus; Sinn, Bruno V.; Eils, Roland; Giese, Nathalia A.; Hackert, Thilo; Strobel, Oliver; Werner, Jens; Büchler, Markus W.; Weichert, Wilko; Trumpp, Andreas; Sprick, Martin R.

    2016-01-01

    Although subtypes of pancreatic ductal adenocarcinoma (PDAC) were described, this malignancy is clinically still treated as a single disease. Here, we present patient-derived models representing the full spectrum of previously identified quasi-mesenchymal (QM-PDA), classical and exocrine-like PDAC subtypes, and identify two markers—HNF1A and KRT81—that enable stratification of tumors into different subtypes by immunohistochemistry. Individuals bearing tumors of these subtypes show significant differences in overall survival and their tumors differ in drug sensitivity, with the exocrine-like subtype being resistant to tyrosine kinase inhibitors and paclitaxel. Cytochrome P450 3A5 (CYP3A5) metabolizes these compounds in tumors of the exocrine-like subtype, and pharmacological or shRNA-mediated CYP3A5 inhibition sensitizes tumor cells to these drugs. Whereas hepatocyte nuclear factor 4 alpha (HNF4A) controls basal expression of CYP3A5, drug-induced CYP3A5 upregulation is mediated by the nuclear receptor NR1I2. CYP3A5 also contributes to acquired drug resistance in QM-PDA and classical PDAC, and is highly expressed in several additional malignancies. These findings designate CYP3A5 as predictor of therapy response and as a tumor cell-autonomous detoxification mechanism that must be overcome to prevent drug resistance. PMID:26855150

  11. Hospital-Acquired Methicillin-resistant Staphylococcus aureus Bacteremia Related to Medicare Antibiotic Prescriptions: A State-Level Analysis

    PubMed Central

    Sumida, Wesley K; Taira, Deborah A; Davis, James W; Seto, Todd B

    2016-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) results in almost half of all deaths caused by antibiotic resistant organisms. Current evidence suggests that MRSA infections are associated with antibiotic use. This study examined state-level data to determine whether outpatient antibiotic use was associated with hospital-acquired MRSA (HA-MRSA) infections. The 2013 Centers for Disease Control and Prevention (CDC) Healthcare-Associated Infections Progress Report was used to obtain HA-MRSA infection rates. Data on the number of antibiotic prescriptions with activity towards methicillin-sensitive Staphylococcus aureus (MSSA) at the state level were obtained from the 2013 Medicare Provider Utilization and Payment Data: Part D Prescriber Public Use File. Pearson's correlation coefficient was used to analyze the relationship between the number of antibiotic prescriptions and HA-MRSA infection rates. The average number of HA-MRSA infections was 0.026 per 1000 persons with the highest rates concentrated in Southeastern and Northeastern states. The average number of outpatient prescriptions per capita was 0.74 with the highest rates in Southeastern states. A significant correlation (ρ = 0.64, P <.001) between infections and prescriptions was observed, even after adjusting for non-reporting hospitals. This association provides evidence of the importance of appropriate antibiotic prescribing. Prescriber and heat map data may be useful for targeting antimicrobial stewardship programs in an effort to manage appropriate antibiotic use to help stop antibiotic resistance. PMID:27738564

  12. CYP3A5 mediates basal and acquired therapy resistance in different subtypes of pancreatic ductal adenocarcinoma.

    PubMed

    Noll, Elisa M; Eisen, Christian; Stenzinger, Albrecht; Espinet, Elisa; Muckenhuber, Alexander; Klein, Corinna; Vogel, Vanessa; Klaus, Bernd; Nadler, Wiebke; Rösli, Christoph; Lutz, Christian; Kulke, Michael; Engelhardt, Jan; Zickgraf, Franziska M; Espinosa, Octavio; Schlesner, Matthias; Jiang, Xiaoqi; Kopp-Schneider, Annette; Neuhaus, Peter; Bahra, Marcus; Sinn, Bruno V; Eils, Roland; Giese, Nathalia A; Hackert, Thilo; Strobel, Oliver; Werner, Jens; Büchler, Markus W; Weichert, Wilko; Trumpp, Andreas; Sprick, Martin R

    2016-03-01

    Although subtypes of pancreatic ductal adenocarcinoma (PDAC) have been described, this malignancy is clinically still treated as a single disease. Here we present patient-derived models representing the full spectrum of previously identified quasi-mesenchymal (QM-PDA), classical and exocrine-like PDAC subtypes, and identify two markers--HNF1A and KRT81--that enable stratification of tumors into different subtypes by using immunohistochemistry. Individuals with tumors of these subtypes showed substantial differences in overall survival, and their tumors differed in drug sensitivity, with the exocrine-like subtype being resistant to tyrosine kinase inhibitors and paclitaxel. Cytochrome P450 3A5 (CYP3A5) metabolizes these compounds in tumors of the exocrine-like subtype, and pharmacological or short hairpin RNA (shRNA)-mediated CYP3A5 inhibition sensitizes tumor cells to these drugs. Whereas hepatocyte nuclear factor 4, alpha (HNF4A) controls basal expression of CYP3A5, drug-induced CYP3A5 upregulation is mediated by the nuclear receptor NR1I2. CYP3A5 also contributes to acquired drug resistance in QM-PDA and classical PDAC, and it is highly expressed in several additional malignancies. These findings designate CYP3A5 as a predictor of therapy response and as a tumor cell-autonomous detoxification mechanism that must be overcome to prevent drug resistance. PMID:26855150

  13. Draft Genome Sequence of a Pathogenic O86:H25 Sequence Type 57 Escherichia coli Strain Isolated from Poultry and Carrying 12 Acquired Antibiotic Resistance Genes.

    PubMed

    Jones-Dias, Daniela; Manageiro, Vera; Sampaio, Daniel Ataíde; Vieira, Luís; Caniça, Manuela

    2015-01-01

    Escherichia coli is a commensal bacterium that is frequently associated with multidrug-resistant zoonotic and foodborne infections. Here, we report the 5.6-Mbp draft genome sequence of an E. coli recovered from poultry, which encodes multiple acquired antibiotic resistance determinants, virulence factors, pathogenicity determinants, and mobile genetic elements. PMID:26404585

  14. Draft Genome Sequence of Extremely Drug-Resistant Pseudomonas aeruginosa (ST357) Strain CMC_VB_PA_B22862 Isolated from a Community-Acquired Bloodstream Infection

    PubMed Central

    Pragasam, Agila Kumari; Yesurajan, Francis; Doss C, George Priya; George, Biju; Devanga Ragupathi, Naveen Kumar; Walia, Kamini

    2016-01-01

    Extremely drug-resistant Pseudomonas aeruginosa strains causing severe infections have become a serious concern across the world. Here, we report draft genome sequence of P. aeruginosa with an extremely drug-resistant profile isolated from a patient with community-acquired bloodstream infection in India. PMID:27795257

  15. Apparent Acquired Resistance by a Weevil to Its Parasitoid Is Influenced by Host Plant

    PubMed Central

    Goldson, Stephen L.; Tomasetto, Federico

    2016-01-01

    Field parasitism rates of the Argentine stem weevil Listronotus bonariensis (Kuschel; Coleoptera: Curculionidae) by Microctonus hyperodae Loan (Hymenoptera: Braconidae) are known to vary according to different host Lolium species that also differ in ploidy. To further investigate this, a laboratory study was conducted to examine parasitism rates on tetraploid Italian Lolium multiflorum, diploid Lolium perenne and diploid hybrid L. perenne ×L. multiflorum; none of which were infected by Epichloë endophyte. At the same time, the opportunity was taken to compare the results of this study with observations made during extensive laboratory-based research and parasitoid-rearing in the 1990s using the same host plant species. This made it possible to determine whether there has been any change in weevil susceptibility to the parasitoid over a 20 year period when in the presence of the tetraploid Italian, diploid perennial and hybrid host grasses that were commonly in use in the 1990’s. The incidence of parasitism in cages, in the presence of these three grasses mirrored what has recently been observed in the field. When caged, weevil parasitism rates in the presence of a tetraploid Italian ryegrass host were significantly higher (75%) than rates that occurred in the presence of either the diploid perennial (46%) or the diploid hybrid (52%) grass, which were not significantly different from each other. This is very different to laboratory parasitism rates in the 1990s when in the presence of both of the latter grasses high rates of parasitism (c. 75%) were recorded. These high rates are typical of those still found in weevils in the presence of both field and caged tetraploid Italian grasses. In contrast, the abrupt decline in weevil parasitism rates points to the possibility of evolved resistance by the weevil to the parasitoid in the diploid and hybrid grasses, but not so in the tetraploid. The orientation of plants in the laboratory cages had no significant effect

  16. Apparent Acquired Resistance by a Weevil to Its Parasitoid Is Influenced by Host Plant.

    PubMed

    Goldson, Stephen L; Tomasetto, Federico

    2016-01-01

    Field parasitism rates of the Argentine stem weevil Listronotus bonariensis (Kuschel; Coleoptera: Curculionidae) by Microctonus hyperodae Loan (Hymenoptera: Braconidae) are known to vary according to different host Lolium species that also differ in ploidy. To further investigate this, a laboratory study was conducted to examine parasitism rates on tetraploid Italian Lolium multiflorum, diploid Lolium perenne and diploid hybrid L. perenne ×L. multiflorum; none of which were infected by Epichloë endophyte. At the same time, the opportunity was taken to compare the results of this study with observations made during extensive laboratory-based research and parasitoid-rearing in the 1990s using the same host plant species. This made it possible to determine whether there has been any change in weevil susceptibility to the parasitoid over a 20 year period when in the presence of the tetraploid Italian, diploid perennial and hybrid host grasses that were commonly in use in the 1990's. The incidence of parasitism in cages, in the presence of these three grasses mirrored what has recently been observed in the field. When caged, weevil parasitism rates in the presence of a tetraploid Italian ryegrass host were significantly higher (75%) than rates that occurred in the presence of either the diploid perennial (46%) or the diploid hybrid (52%) grass, which were not significantly different from each other. This is very different to laboratory parasitism rates in the 1990s when in the presence of both of the latter grasses high rates of parasitism (c. 75%) were recorded. These high rates are typical of those still found in weevils in the presence of both field and caged tetraploid Italian grasses. In contrast, the abrupt decline in weevil parasitism rates points to the possibility of evolved resistance by the weevil to the parasitoid in the diploid and hybrid grasses, but not so in the tetraploid. The orientation of plants in the laboratory cages had no significant effect on

  17. Apparent Acquired Resistance by a Weevil to Its Parasitoid Is Influenced by Host Plant

    PubMed Central

    Goldson, Stephen L.; Tomasetto, Federico

    2016-01-01

    Field parasitism rates of the Argentine stem weevil Listronotus bonariensis (Kuschel; Coleoptera: Curculionidae) by Microctonus hyperodae Loan (Hymenoptera: Braconidae) are known to vary according to different host Lolium species that also differ in ploidy. To further investigate this, a laboratory study was conducted to examine parasitism rates on tetraploid Italian Lolium multiflorum, diploid Lolium perenne and diploid hybrid L. perenne ×L. multiflorum; none of which were infected by Epichloë endophyte. At the same time, the opportunity was taken to compare the results of this study with observations made during extensive laboratory-based research and parasitoid-rearing in the 1990s using the same host plant species. This made it possible to determine whether there has been any change in weevil susceptibility to the parasitoid over a 20 year period when in the presence of the tetraploid Italian, diploid perennial and hybrid host grasses that were commonly in use in the 1990’s. The incidence of parasitism in cages, in the presence of these three grasses mirrored what has recently been observed in the field. When caged, weevil parasitism rates in the presence of a tetraploid Italian ryegrass host were significantly higher (75%) than rates that occurred in the presence of either the diploid perennial (46%) or the diploid hybrid (52%) grass, which were not significantly different from each other. This is very different to laboratory parasitism rates in the 1990s when in the presence of both of the latter grasses high rates of parasitism (c. 75%) were recorded. These high rates are typical of those still found in weevils in the presence of both field and caged tetraploid Italian grasses. In contrast, the abrupt decline in weevil parasitism rates points to the possibility of evolved resistance by the weevil to the parasitoid in the diploid and hybrid grasses, but not so in the tetraploid. The orientation of plants in the laboratory cages had no significant effect

  18. Surveillance of hospital-acquired methicillin-resistant Staphylococcus aureus in South Australia.

    PubMed

    Cooper, Celia; Ochota, Meredith A

    2003-01-01

    In September 2001, the South Australian state-wide methicillin-resistant Staphylococcus aureus (MRSA) surveillance system was expanded to include three surveillance indicators namely: estimated MRSA burden, MRSA morbidity and estimated MRSA acquisition. The last two indicator rates have been stratified into intensive care unit (ICU) versus non-ICU. Between September 2001 and March 2002, state-wide MRSA burden rates (prevalence) ranged from 27.5 to 39.8 per 10,000 occupied bed days (OBDs). Acquisition rates ranged from 28.2 to 69.0 per 10,000 OBDs (ICU) and 6.3 to 10.1 per 10,000 OBDs (non-ICU). Morbidity rates ranged from 12.9 to 43.1 per 10,000 OBDs (ICU) and 3.0 to 5.0 per 10,000 OBDs (non-ICU). In association with the changes to surveillance indicators, a new monthly surveillance report was developed. Assuring confidentiality to individual contributing hospitals has been a major consideration in the development of the data collection system. Individual contributors have access only to their own indicator rates and pooled state-wide indicator rates. Contributing institutions are urged to use great caution if wishing to compare their own rates with state-wide rates. In particular, contributors are asked to take inter-institutional differences in MRSA burden and casemix complexity into account when making such comparisons.

  19. A novel elicitor protein from Phytophthora parasitica induces plant basal immunity and systemic acquired resistance.

    PubMed

    Chang, Yi-Hsuan; Yan, Hao-Zhi; Liou, Ruey-Fen

    2015-02-01

    The interaction between Phytophthora pathogens and host plants involves the exchange of complex molecular signals from both sides. Recent studies of Phytophthora have led to the identification of various apoplastic elicitors known to trigger plant immunity. Here, we provide evidence that the protein encoded by OPEL of Phytophthora parasitica is a novel elicitor. Homologues of OPEL were identified only in oomycetes, but not in fungi and other organisms. Quantitative reverse transcription-polymerase chain reaction (RT-PCR) revealed that OPEL is expressed throughout the development of P. parasitica and is especially highly induced after plant infection. Infiltration of OPEL recombinant protein from Escherichia coli into leaves of Nicotiana tabacum (cv. Samsun NN) resulted in cell death, callose deposition, the production of reactive oxygen species and induced expression of pathogen-associated molecular pattern (PAMP)-triggered immunity markers and salicylic acid-responsive defence genes. Moreover, the infiltration conferred systemic resistance against a broad spectrum of pathogens, including Tobacco mosaic virus, the bacteria wilt pathogen Ralstonia solanacearum and P. parasitica. In addition to the signal peptide, OPEL contains three conserved domains: a thaumatin-like domain, a glycine-rich protein domain and a glycosyl hydrolase (GH) domain. Intriguingly, mutation of a putative laminarinase active site motif in the predicted GH domain abolished its elicitor activity, which suggests enzymatic activity of OPEL in triggering the defence response.

  20. Convergence of Acquired Mutations and Alternative Splicing of CD19 Enables Resistance to CART-19 Immunotherapy

    PubMed Central

    Sotillo, Elena; Barrett, David M.; Black, Kathryn L; Bagashev, Asen; Oldridge, Derek; Wu, Glendon; Sussman, Robyn; Lanauze, Claudia; Ruella, Marco; Gazzara, Matthew R.; Martinez, Nicole M.; Harrington, Colleen T.; Chung, Elaine Y.; Perazzelli, Jessica; Hofmann, Ted J.; Maude, Shannon L.; Raman, Pichai; Barrera, Alejandro; Gill, Saar; Lacey, Simon F.; Melenhorst, Jan J.; Allman, David; Jacoby, Elad; Fry, Terry; Mackall, Crystal; Barash, Yoseph; Lynch, Kristen W.; Maris, John M.; Grupp, Stephan A.; Thomas-Tikhonenko, Andrei

    2015-01-01

    The CD19 antigen, expressed on most B-cell acute lymphoblastic leukemias (B-ALL), can be targeted with chimeric antigen receptor–armed T cells (CART-19), but relapses with epitope loss occur in 10% to 20% of pediatric responders. We detected hemizygous deletions spanning the CD19 locus and de novo frameshift and missense mutations in exon 2 of CD19 in some relapse samples. However, we also discovered alternatively spliced CD19 mRNA species, including one lacking exon 2. Pull-down/siRNA experiments identified SRSF3 as a splicing factor involved in exon 2 retention, and its levels were lower in relapsed B-ALL. Using genome editing, we demonstrated that exon 2 skipping bypasses exon 2 mutations in B-ALL cells and allows expression of the N-terminally truncated CD19 variant, which fails to trigger killing by CART-19 but partly rescues defects associated with CD19 loss. Thus, this mechanism of resistance is based on a combination of deleterious mutations and ensuing selection for alternatively spliced RNA isoforms. Significance CART-19 yield 70% response rates in patients with B-ALL, but also produce escape variants. We discovered that the underlying mechanism is the selection for preexisting alternatively spliced CD19 isoforms with the compromised CART-19 epitope. This mechanism suggests a possibility of targeting alternative CD19 ectodomains, which could improve survival of patients with B-cell neoplasms. PMID:26516065

  1. Staphylococcal enterotoxin B toxic shock syndrome induced by community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA).

    PubMed

    Kashiwada, Takeru; Kikuchi, Ken; Abe, Shinji; Kato, Hidehito; Hayashi, Hiroki; Morimoto, Taisuke; Kamio, Koichiro; Usuki, Jiro; Takeda, Shinhiro; Tanaka, Keiji; Imanishi, Ken'ichi; Yagi, Junji; Azuma, Arata; Gemma, Akihiko

    2012-01-01

    We herein report a case of toxic shock syndrome (TSS) associated with the 2009 pandemic H1N1 (pH1N1) influenza virus and a community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infection in a 16-year-old Vietnamese girl. Staphylococcal enterotoxin B (SEB) was detected in the patient's serum, and the level of anti-SEB antibodies was found to be elevated. A flow cytometric analysis showed evidence of activated SEB-reactive Vβ3+ and Vβ12+ T cells. These data suggest that the CA-MRSA-induced activation of SEB-reactive T cells may cause TSS in patients with pH1N1 virus infection. Moreover, this is the first report describing immunological confirmation of SEB contributing directly to TSS in a patient fulfilling the diagnostic criteria of TSS.

  2. Reactivation of hepatitis B virus after withdrawal of erlotinib

    PubMed Central

    Bui, N.; Wong-Sefidan, I.

    2015-01-01

    Reactivation of hepatitis B virus (hbv) is a reported complication for patients undergoing chemotherapy, particularly immunochemotherapy with anti-CD20 agents such as rituximab. However, as the use of molecularly targeted agents increases, the risk of viral reactivation is less clearly defined. Here, we present the case of a 62-year-old woman with newly diagnosed EGFR mutation–positive metastatic non-small-cell lung cancer (nsclc). Per interview, our patient had a remote history of hbv infection. She was started on erlotinib and developed profound diarrhea leading to renal failure that required hospital admission and temporary discontinuation of erlotinib. At 8 days after erlotinib cessation, she had a marked spike in her liver function tests, with viral serologies that were consistent with hbv reactivation. Although erlotinib and other tyrosine kinase inhibitors (tkis) are not classically associated with hbv reactivation, hbv reactivation can occur even in the setting of tki withdrawal. Before tki initiation, careful patient screening in those at risk for hbv should be performed to attenuate preventable hepatotoxicity and to differentiate between other causes of hepatotoxicity (for example, drug-induced toxicity). PMID:26715877

  3. Metabolomic analysis reveals the relationship between AZI1 and sugar signaling in systemic acquired resistance of Arabidopsis.

    PubMed

    Wang, Xiao-Yan; Li, Dian-Zhen; Li, Qi; Ma, Yan-Qin; Yao, Jing-Wen; Huang, Xuan; Xu, Zi-Qin

    2016-10-01

    The function of AZI1 in systemic acquired resistance of Arabidopsis was confirmed by investigation of the phenotypic features of wild-type Col-0, AZI1 T-DNA knockout and AZI1 overexpressing plants after infection with virulent and avirulent Pseudomonas syringae. Real-time quantitative PCR and Northern blotting analyses showed that the transcript abundances of PR genes increased significantly in local and systemic leaves of wild-type Col-0 and AZI1 overexpressing plants challenged with avirulent P. syringae, whereas the mRNA accumulation of PR genes was obviously attenuated in local and systemic leaves of AZI1 T-DNA knockout plants after localized infiltration with avirulent Psm avrRpm1. The changes of metabolomic profiles in distal leaves of three types of materials infected with avirulent P. syringae were determined by (1)H NMR spectrometry and data mining showed that the soluble carbonhydrates might function as signal substances in the systemic immunity of Arabidopsis. At the same time, the expression of the sugar signaling genes in local and distal leaves after infection of avirulent P. syringae was compared. As a result, it was found that the transcript abundances of sugar signaling genes, including SUS1, SUS2, SUS3, SUS6, SUT1, HXK1, HXK2, SNRK1.2, ERD6, TPS1, TOR, SNRK1.1, SNRK1.3 and bZIP11, were obviously changed in distal leaves of different materials with the modulated AZI1 activities, indicating sugar-related genes are involved in regulation of the systemic immunity mediated by AZI1. These results also illustrated that the immune system associated with sugar molecules probably was an important part of the systemic acquired resistance in Arabidopsis.

  4. Increased thymidylate synthase in L1210 cells possessing acquired resistance to N10-propargyl-5,8-dideazafolic acid (CB3717): development, characterization, and cross-resistance studies

    SciTech Connect

    Jackman, A.L.; Alison, D.L.; Calvert, A.H.; Harrap, K.R.

    1986-06-01

    The properties are described of a mutant L1210 cell line (L1210:C15) with acquired resistance (greater than 200-fold) to the thymidylate synthase (TS) inhibitor N10-propargyl-5,8-dideazafolic acid. TS was overproduced 45-fold and was accompanied by a small increase in the activity of dihydrofolate reductase (2.6-fold). Both the level of resistance and enzyme activities were maintained in drug-free medium (greater than 300 generations). Failure of N10-propargyl-5,8-dideazafolic acid to suppress the (/sup 3/H)-2'-deoxyuridine incorporation into the acid-precipitable material of the resistant line supported the evidence that TS overproduction was the mechanism of resistance; consequently the L1210:C15 cells were largely cross-resistant to another (but weaker) TS inhibitor, 5,8-dideazafolic acid. Minimal cross-resistance was observed to the dihydrofolate reductase inhibitors methotrexate and 5-methyl-5,8-dideazaaminopterin (5- and 2-fold, respectively). L1210 and L1210:C15 cells were, however, equally sensitive to 5-fluorodeoxyuridine (FdUrd), an unexpected finding since a metabolite, 5-fluorodeoxyuridine monophosphate, is a potent TS inhibitor; however, this cytotoxicity against the L1210:C15 cells was antagonized by coincubation with 5 microM folinic acid although folinic acid potentiated the cytotoxicity of FdUrd to the N10-propargyl-5,8-dideazafolic acid-sensitive L1210 line. Thymidine was much less effective as a FdUrd protecting agent in the L1210:C15 when compared with the L1210 cells; however, a combination of thymidine plus hypoxanthine was without any additional effect (compared with thymidine alone) against the sensitive line but effectively protected L1210:C15 cells.

  5. Diverse drug-resistance mechanisms can emerge from drug-tolerant cancer persister cells

    PubMed Central

    Ramirez, Michael; Rajaram, Satwik; Steininger, Robert J.; Osipchuk, Daria; Roth, Maike A.; Morinishi, Leanna S.; Evans, Louise; Ji, Weiyue; Hsu, Chien-Hsiang; Thurley, Kevin; Wei, Shuguang; Zhou, Anwu; Koduru, Prasad R.; Posner, Bruce A.; Wu, Lani F.; Altschuler, Steven J.

    2016-01-01

    Cancer therapy has traditionally focused on eliminating fast-growing populations of cells. Yet, an increasing body of evidence suggests that small subpopulations of cancer cells can evade strong selective drug pressure by entering a ‘persister' state of negligible growth. This drug-tolerant state has been hypothesized to be part of an initial strategy towards eventual acquisition of bona fide drug-resistance mechanisms. However, the diversity of drug-resistance mechanisms that can expand from a persister bottleneck is unknown. Here we compare persister-derived, erlotinib-resistant colonies that arose from a single, EGFR-addicted lung cancer cell. We find, using a combination of large-scale drug screening and whole-exome sequencing, that our erlotinib-resistant colonies acquired diverse resistance mechanisms, including the most commonly observed clinical resistance mechanisms. Thus, the drug-tolerant persister state does not limit—and may even provide a latent reservoir of cells for—the emergence of heterogeneous drug-resistance mechanisms. PMID:26891683

  6. Acute haematogenous community-acquired methicillin-resistant Staphylococcus aureus osteomyelitis in an adult: Case report and review of literature

    PubMed Central

    2012-01-01

    Background Methicillin-resistant Staphylococcus aureus (MRSA) has of late emerged as a cause of community-acquired infections among immunocompetent adults without risk factors. Skin and soft tissue infections represent the majority of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) clinical presentations, whilst invasive and life-threatening illness like necrotizing pneumonia, necrotizing fasciitis, pyomyositis, osteomyelitis and sepsis syndrome are less common. Although more widely described in the pediatric age group, the occurrence of CA-MRSA osteomyelitis in adults is an uncommonly reported entity. Case presentation We describe an invasive CA-MRSA infection in a 28 year-old previously healthy male, manifesting with bacteraemia, osteomyelitis of femur, pyomyositis and septic arthritis of the knee. Initially a preliminary diagnosis of osteosarcoma was suggested by imaging studies and patient underwent a bone biopsy. MRSA was subsequently isolated from blood cultures taken on day of admission, bone, tissue and pus cultures. Incision and drainage of abscess was performed and patient was treated with vancomycin, with fusidic acid added later. It took 6 months for the inflammatory markers to normalize, warranting 6-months of anti-MRSA therapy. Patient was a fervent deer hunter and we speculate that he acquired this infection from extensive direct contact with deer. Molecular characterization of this isolate showed that it belonged to multilocus sequence type (MLST) ST30 and exhibited the staphylococcal chromosome cassette mec (SCCmec) type IV, staphylococcus protein A (spa) type t019, accessory gene regulator (agr) type III and dru type dt10m. This strain harbored Panton-Valentine leukocidin (pvl) genes together with 3 other virulent genes; sei (enterotoxin), hlg (hemolysin) and fnbA (fibronectin binding protein). Conclusion This case study alerts physicians that beyond the most commonly encountered skin and soft tissue infections, pvl

  7. Lack of acquired resistance in dogs to successive infestations of Rhipicephalus sanguineus ticks from Brazil and Argentina.

    PubMed

    Évora, Patricia Martinez; Sanches, Gustavo Seron; Jusi, Márcia Mariza Gomes; Alves, Lucas Bocchini Rodrigues; Machado, Rosangela Zacarias; Bechara, Gervásio Henrique

    2015-09-01

    Comparative studies between brown dog tick Rhipicephalus sanguineus populations from Brazil (Jaboticabal, São Paulo) and Argentina (Rafaela, Santa Fé) showed significant biological, morphological and genetic differences between them. This work aimed to study, in a comparative way, the acquisition of resistance in domestic dogs to R. sanguineus from Jaboticabal and Rafaela, after successive and controlled infestations. Ticks were kept in a BOD incubator under controlled conditions (27 °C, 80 % relative humidity, 12-h photoperiod). Ten dogs, Dachshund breed, males and females, 6 months old, short- or long-haired, without prior contact with ticks, were used as hosts. They were distributed into two experimental groups composed of five animals each: G1 infested with ten adult couples of R. sanguineus (Jaboticabal) per animal, and G2 infested with ten adult couples of R. sanguineus (Rafaela) per animal. Ticks' biological parameters and titration of antibodies from the dogs' sera by ELISA test were used for comparison between the strains. Results of the biological parameters showed that the dogs did not acquire immunity to either of the R. sanguineus strains after repeated infestations. The ELISA test showed low antibody titers in sera of dogs from G2, in successive infestations, and higher antibody responses post second and third infestations in G1. It also demonstrated cross-reactivity between sera of dogs infested with R. sanguineus (Jaboticabal) and antigens from R. sanguineus (Rafaela) and vice versa. We conclude that Dachshund dogs did not develop resistance against neither Jaboticabal nor Rafaela strains of R. sanguineus.

  8. CXCR4-targeted lipid-coated PLGA nanoparticles deliver sorafenib and overcome acquired drug resistance in liver cancer.

    PubMed

    Gao, Dong-Yu; Lin, Ts-Ting; Sung, Yun-Chieh; Liu, Ya Chi; Chiang, Wen-Hsuan; Chang, Chih-Chun; Liu, Jia-Yu; Chen, Yunching

    2015-10-01

    Sorafenib, a multikinase inhibitor, has been used as an anti-angiogenic agent against highly vascular hepatocellular carcinoma (HCC) - yet associated with only moderate therapeutic effect and the high incidence of HCC recurrence. We have shown intratumoral hypoxia induced by sorafenib activated C-X-C receptor type 4 (CXCR4)/stromal-derived factor 1α (SDF1α) axis, resulting in polarization toward a tumor-promoting microenvironment and resistance to anti-angiogenic therapy in HCC. Herein, we formulated sorafenib in CXCR4-targeted lipid-coated poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) modified with a CXCR4 antagonist, AMD3100 to systemically deliver sorafenib into HCC and sensitize HCC to sorafenib treatment. We demonstrated that CXCR4-targeted NPs efficiently delivered sorafenib into HCCs and human umbilical vein endothelial cells (HUVECs) to achieve cytotoxicity and anti-angiogenic effect in vitro and in vivo. Despite the increased expression of SDF1α upon the persistent hypoxia induced by sorafenib-loaded CXCR4-targeted NPs, AMD3100 attached to the NPs can block CXCR4/SDF1α, leading to the reduced infiltration of tumor-associated macrophages, enhanced anti-angiogenic effect, a delay in tumor progression and increased overall survival in the orthotopic HCC model compared with other control groups. In conclusion, our results highlight the clinical potential of CXCR4-targeted NPs for delivering sorafenib and overcoming acquired drug resistance in liver cancer.

  9. Potential therapeutic drug target identification in Community Acquired-Methicillin Resistant Staphylococcus aureus (CA-MRSA) using computational analysis.

    PubMed

    Yadav, Pramod Kumar; Singh, Gurmit; Singh, Satendra; Gautam, Budhayash; Saad, Esmaiel If

    2012-01-01

    The emergence of multidrug-resistant strain of community-acquired methicillin resistant Staphylococcus aureus (CA-MRSA) strain has highlighted the urgent need for the alternative and effective therapeutic approach to combat the menace of this nosocomial pathogen. In the present work novel potential therapeutic drug targets have been identified through the metabolic pathways analysis. All the gene products involved in different metabolic pathways of CA-MRSA in KEGG database were searched against the proteome of Homo sapiens using the BLASTp program and the threshold of E-value was set to as 0.001. After database searching, 152 putative targets were identified. Among all 152 putative targets, 39 genes encoding for putative targets were identified as the essential genes from the DEG database which are indispensable for the survival of CA-MRSA. After extensive literature review, 7 targets were identified as potential therapeutic drug target. These targets are Fructose-bisphosphate aldolase, Phosphoglyceromutase, Purine nucleoside phosphorylase, Uridylate kinase, Tryptophan synthase subunit beta, Acetate kinase and UDP-N-acetylglucosamine 1-carboxyvinyltransferase. Except Uridylate kinase all the identified targets were involved in more than one metabolic pathways of CA-MRSA which underlines the importance of drug targets. These potential therapeutic drug targets can be exploited for the discovery of novel inhibitors for CA-MRSA using the structure based drug design (SBDD) strategy.

  10. Tunable-combinatorial mechanisms of acquired resistance limit the efficacy of BRAF/MEK cotargeting but result in melanoma drug addiction.

    PubMed

    Moriceau, Gatien; Hugo, Willy; Hong, Aayoung; Shi, Hubing; Kong, Xiangju; Yu, Clarissa C; Koya, Richard C; Samatar, Ahmed A; Khanlou, Negar; Braun, Jonathan; Ruchalski, Kathleen; Seifert, Heike; Larkin, James; Dahlman, Kimberly B; Johnson, Douglas B; Algazi, Alain; Sosman, Jeffrey A; Ribas, Antoni; Lo, Roger S

    2015-02-01

    Combined BRAF- and MEK-targeted therapy improves upon BRAF inhibitor (BRAFi) therapy but is still beset by acquired resistance. We show that melanomas acquire resistance to combined BRAF and MEK inhibition by augmenting or combining mechanisms of single-agent BRAFi resistance. These double-drug resistance-associated genetic configurations significantly altered molecular interactions underlying MAPK pathway reactivation. (V600E)BRAF, expressed at supraphysiological levels because of (V600E)BRAF ultra-amplification, dimerized with and activated CRAF. In addition, MEK mutants enhanced interaction with overexpressed (V600E)BRAF via a regulatory interface at R662 of (V600E)BRAF. Importantly, melanoma cell lines selected for resistance to BRAFi+MEKi, but not those to BRAFi alone, displayed robust drug addiction, providing a potentially exploitable therapeutic opportunity.

  11. Tunable-combinatorial Mechanisms of Acquired Resistance Limit the Efficacy of BRAF/MEK Co-targeting but Result in Melanoma Drug Addiction

    PubMed Central

    Moriceau, Gatien; Hugo, Willy; Hong, Aayoung; Shi, Hubing; Kong, Xiangju; Yu, Clarissa C.; Koya, Richard C.; Samatar, Ahmed A.; Khanlou, Negar; Braun, Jonathan; Ruchalski, Kathleen; Seifert, Heike; Larkin, James; Dahlman, Kimberly B.; Johnson, Douglas B.; Algazi, Alain; Sosman, Jeffrey A.; Ribas, Antoni; Lo, Roger S.

    2014-01-01

    SUMMARY Combined BRAF and MEK targeted therapy improves upon BRAF inhibitor (BRAFi) therapy but is still beset by acquired resistance. We show that melanomas acquire resistance to combined BRAF and MEK inhibition by augmenting or combining mechanisms of single-agent BRAFi resistance. These double-drug resistance-associated genetic configurations significantly altered molecular interactions underlying MAPK pathway reactivation. V600EBRAF, expressed at supra-physiological levels because of V600EBRAF ultra-amplification, dimerized with and activated CRAF. In addition, MEK mutants enhanced interaction with over-expressed V600EBRAF via a regulatory interface at R662 of V600EBRAF. Importantly, melanoma cell lines selected for resistance to BRAFi+MEKi, but not those to BRAFi alone, displayed robust drug addiction, providing a potentially exploitable therapeutic opportunity. PMID:25600339

  12. Arabidopsis ENHANCED DISEASE SUSCEPTIBILITY1 promotes systemic acquired resistance via azelaic acid and its precursor 9-oxo nonanoic acid.

    PubMed

    Wittek, Finni; Hoffmann, Thomas; Kanawati, Basem; Bichlmeier, Marlies; Knappe, Claudia; Wenig, Marion; Schmitt-Kopplin, Philippe; Parker, Jane E; Schwab, Wilfried; Vlot, A Corina

    2014-11-01

    Systemic acquired resistance (SAR) is a form of inducible disease resistance that depends on salicylic acid and its upstream regulator ENHANCED DISEASE SUSCEPTIBILITY1 (EDS1). Although local Arabidopsis thaliana defence responses activated by the Pseudomonas syringae effector protein AvrRpm1 are intact in eds1 mutant plants, SAR signal generation is abolished. Here, the SAR-specific phenotype of the eds1 mutant is utilized to identify metabolites that contribute to SAR. To this end, SAR bioassay-assisted fractionation of extracts from the wild type compared with eds1 mutant plants that conditionally express AvrRpm1 was performed. Using high-performance liquid chromatography followed by mass spectrometry, systemic immunity was associated with the accumulation of 60 metabolites, including the putative SAR signal azelaic acid (AzA) and its precursors 9-hydroperoxy octadecadienoic acid (9-HPOD) and 9-oxo nonanoic acid (ONA). Exogenous ONA induced SAR in systemic untreated leaves when applied at a 4-fold lower concentration than AzA. The data suggest that in planta oxidation of ONA to AzA might be partially responsible for this response and provide further evidence that AzA mobilizes Arabidopsis immunity in a concentration-dependent manner. The AzA fragmentation product pimelic acid did not induce SAR. The results link the C9 lipid peroxidation products ONA and AzA with systemic rather than local resistance and suggest that EDS1 directly or indirectly promotes the accumulation of ONA, AzA, or one or more of their common precursors possibly by activating one or more pathways that either result in the release of these compounds from galactolipids or promote lipid peroxidation.

  13. Acute myocardial infarction following erlotinib treatment for NSCLC: A case report

    PubMed Central

    DING, SHANSHAN; LONG, FEI; JIANG, SHUJUAN

    2016-01-01

    Erlotinib, an epidermal growth factor receptor tyrosine kinase inhibitor, is an oral targeted anticancer drug that is used to treat non-small cell lung cancer (NSCLC). Previous studies have confirmed that erlotinib is safe and is well-tolerated by patients. The most common adverse reactions observed following erlotinib treatment include a rash and mild diarrhea. In the current study, the first case of acute myocardial infarction following one month of treatment with erlotinib in a 63-year-old male NSCLC patient is presented. The present study highlights the importance of clinicians remaining cautious following erlotinib administration. In elderly NSCLC patients and those with a history of coronary heart disease, cardiac function must be carefully monitored following erlotinib treatment so that serious adverse reactions, such as myocardial infarction, may be identified early and treated quickly. PMID:27313772

  14. Targeting glucosylceramide synthase induction of cell surface globotriaosylceramide (Gb3) in acquired cisplatin-resistance of lung cancer and malignant pleural mesothelioma cells

    SciTech Connect

    Tyler, Andreas; Johansson, Anders; Karlsson, Terese; Gudey, Shyam Kumar; Brännström, Thomas; Grankvist, Kjell; Behnam-Motlagh, Parviz

    2015-08-01

    Background: Acquired resistance to cisplatin treatment is a caveat when treating patients with non-small cell lung cancer (NSCLC) and malignant pleural mesothelioma (MPM). Ceramide increases in response to chemotherapy, leading to proliferation arrest and apoptosis. However, a tumour stress activation of glucosylceramide synthase (GCS) follows to eliminate ceramide by formation of glycosphingolipids (GSLs) such as globotriaosylceramide (Gb3), the functional receptor of verotoxin-1. Ceramide elimination enhances cell proliferation and apoptosis blockade, thus stimulating tumor progression. GSLs transactivate multidrug resistance 1/P-glycoprotein (MDR1) and multidrug resistance-associated protein 1 (MRP1) expression which further prevents ceramide accumulation and stimulates drug efflux. We investigated the expression of Gb3, MDR1 and MRP1 in NSCLC and MPM cells with acquired cisplatin resistance, and if GCS activity or MDR1 pump inhibitors would reduce their expression and reverse cisplatin-resistance. Methods: Cell surface expression of Gb3, MDR1 and MRP1 and intracellular expression of MDR1 and MRP1 was analyzed by flow cytometry and confocal microscopy on P31 MPM and H1299 NSCLC cells and subline cells with acquired cisplatin resistance. The effect of GCS inhibitor PPMP and MDR1 pump inhibitor cyclosporin A for 72 h on expression and cisplatin cytotoxicity was tested. Results: The cisplatin-resistant cells expressed increased cell surface Gb3. Cell surface Gb3 expression of resistant cells was annihilated by PPMP whereas cyclosporin A decreased Gb3 and MDR1 expression in H1299 cells. No decrease of MDR1 by PPMP was noted in using flow cytometry, whereas a decrease of MDR1 in H1299 and H1299res was indicated with confocal microscopy. No certain co-localization of Gb3 and MDR1 was noted. PPMP, but not cyclosporin A, potentiated cisplatin cytotoxicity in all cells. Conclusions: Cell surface Gb3 expression is a likely tumour biomarker for acquired cisplatin

  15. A Typical Hospital-Acquired Methicillin-Resistant Staphylococcus aureus Clone Is Widespread in the Community in the Gaza Strip

    PubMed Central

    Biber, Asaf; Abuelaish, Izeldeen; Rahav, Galia; Raz, Meir; Cohen, Liran; Valinsky, Lea; Taran, Dianna; Goral, Aviva; Elhamdany, Abedalla; Regev-Yochay, Gili

    2012-01-01

    Epidemiological data on community acquired methicillin-resistant-Staphylococcus aureus (CA-MRSA) carriage and infection in the Middle-East region is scarce with only few reports in the Israeli and Palestinian populations. As part of a Palestinian-Israeli collaborative research, we have conducted a cross-sectional survey of nasal S. aureus carriage in healthy children and their parents throughout the Gaza strip. Isolates were characterized for antibiotic susceptibility, mec gene presence, PFGE, spa type, SCCmec-type, presence of PVL genes and multi-locus-sequence-type (MLST). S. aureus was carried by 28.4% of the 379 screened children-parents pairs. MRSA was detected in 45% of S. aureus isolates, that is, in 12% of the study population. A single ST22-MRSA-IVa, spa t223, PVL-gene negative strain was detected in 64% of MRSA isolates. This strain is typically susceptible to all non-β-lactam antibiotics tested. The only predictor for MRSA carriage in children was having an MRSA carrier-parent (OR = 25.5, P = 0.0004). Carriage of the Gaza strain was not associated with prior hospitalization. The Gaza strain was closely related genetically to a local MSSA spa t223 strain and less so to EMRSA15, one of the pandemic hospital-acquired-MRSA clones, scarcely reported in the community. The rapid spread in the community may be due to population determinants or due to yet unknown advantageous features of this particular strain. PMID:22916171

  16. Community-acquired necrotizing pneumonia caused by methicillin-resistant Staphylococcus aureus ST30-SCCmecIVc-spat019-PVL positive in San Antonio de Areco, Argentina.

    PubMed

    Fernandez, Silvina; Murzicato, Sofía; Sandoval, Orlando; Fernández-Canigia, Liliana; Mollerach, Marta

    2015-01-01

    Community-acquired methicillin-resistant Staphylococcus aureus is the first cause of skin and soft tissue infections, but can also produce severe diseases such as bacteremia, osteomyelitis and necrotizing pneumonia. Some S. aureus lineages have been described in cases of necrotizing pneumonia worldwide, usually in young, previously healthy patients. In this work, we describe a fatal case of necrotizing pneumonia due to community-acquired methicillin-resistant S. aureus clone ST30-SCCmecIVc-spat019-PVL positive in an immunocompetent adult patient. PMID:25681265

  17. Community-acquired necrotizing pneumonia caused by methicillin-resistant Staphylococcus aureus ST30-SCCmecIVc-spat019-PVL positive in San Antonio de Areco, Argentina.

    PubMed

    Fernandez, Silvina; Murzicato, Sofía; Sandoval, Orlando; Fernández-Canigia, Liliana; Mollerach, Marta

    2015-01-01

    Community-acquired methicillin-resistant Staphylococcus aureus is the first cause of skin and soft tissue infections, but can also produce severe diseases such as bacteremia, osteomyelitis and necrotizing pneumonia. Some S. aureus lineages have been described in cases of necrotizing pneumonia worldwide, usually in young, previously healthy patients. In this work, we describe a fatal case of necrotizing pneumonia due to community-acquired methicillin-resistant S. aureus clone ST30-SCCmecIVc-spat019-PVL positive in an immunocompetent adult patient.

  18. Erlotinib and gefitinib treatments of the lung cancer in an elderly patient result in gastrointestinal bleeding

    PubMed Central

    Bai, Hongmei; Liu, Qing; Shi, Maowei; Zhang, Jing

    2013-01-01

    Lung cancer is currently one of the leading causes of the cancer-related deaths in the world. Erlotinib and Gefitinib are inhibitors of human epidermal growth factor receptor-1 and the epidermal growth factor receptor tyrosine kinase. The most common adverse events for erlotinib and gefitinib were mild to moderate skin toxicity (rash, itching, and dry skin), gastrointestinal reactions (diarrhea and nausea), and fatigue. Erlotinib induced gastrointestinal bleeding is rare, and dose-related. We are reporting a lung cancer patient who received erlotinib and gefitinib. The patient was sensitive to drug and tumor growth was inhibited. However, adverse reactions appeared as drug treatment continued, including gastrointestinal bleeding. PMID:24353736

  19. Acquired EGFR C797S mutation mediates resistance to AZD9291 in non-small cell lung cancer harboring EGFR T790M.

    PubMed

    Thress, Kenneth S; Paweletz, Cloud P; Felip, Enriqueta; Cho, Byoung Chul; Stetson, Daniel; Dougherty, Brian; Lai, Zhongwu; Markovets, Aleksandra; Vivancos, Ana; Kuang, Yanan; Ercan, Dalia; Matthews, Sarah E; Cantarini, Mireille; Barrett, J Carl; Jänne, Pasi A; Oxnard, Geoffrey R

    2015-06-01

    Here we studied cell-free plasma DNA (cfDNA) collected from subjects with advanced lung cancer whose tumors had developed resistance to the epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) AZD9291. We first performed next-generation sequencing of cfDNA from seven subjects and detected an acquired EGFR C797S mutation in one; expression of this mutant EGFR construct in a cell line rendered it resistant to AZD9291. We then performed droplet digital PCR on serial cfDNA specimens collected from 15 AZD9291-treated subjects. All were positive for the T790M mutation before treatment, but upon developing AZD9291 resistance three molecular subtypes emerged: six cases acquired the C797S mutation, five cases maintained the T790M mutation but did not acquire the C797S mutation and four cases lost the T790M mutation despite the presence of the underlying EGFR activating mutation. Our findings provide insight into the diversity of mechanisms through which tumors acquire resistance to AZD9291 and highlight the need for therapies that are able to overcome resistance mediated by the EGFR C797S mutation.

  20. Healthcare-associated, community-acquired and hospital-acquired bacteraemic urinary tract infections in hospitalized patients: a prospective multicentre cohort study in the era of antimicrobial resistance.

    PubMed

    Horcajada, J P; Shaw, E; Padilla, B; Pintado, V; Calbo, E; Benito, N; Gamallo, R; Gozalo, M; Rodríguez-Baño, J

    2013-10-01

    The clinical and microbiological characteristics of community-onset healthcare-associated (HCA) bacteraemia of urinary source are not well defined. We conducted a prospective cohort study at eight tertiary-care hospitals in Spain, from October 2010 to June 2011. All consecutive adult patients hospitalized with bacteraemic urinary tract infection (BUTI) were included. HCA-BUTI episodes were compared with community-acquired (CA) and hospital-acquired (HA) BUTI. A logistic regression analysis was performed to identify 30-day mortality risk factors. We included 667 episodes of BUTI (246 HCA, 279 CA and 142 HA). Differences between HCA-BUTI and CA-BUTI were female gender (40% vs 69%, p <0.001), McCabe score II-III (48% vs 14%, p <0.001), Pitt score ≥2 (40% vs 31%, p 0.03), isolation of extended spectrum β-lactamase-producing Enterobacteriaciae (13% vs 5%, p <0.001), median hospital stay (9 vs 7 days, p 0.03), inappropriate empirical antimicrobial therapy (21% vs 13%, p 0.02) and mortality (11.4% vs 3.9%, p 0.001). Pseudomonas aeruginosa was more frequently isolated in HA-BUTI (16%) than in HCA-BUTI (4%, p <0.001). Independent factors for mortality were age (OR 1.04; 95% CI 1.01-1.07), McCabe score II-III (OR 3.2; 95% CI 1.8-5.5), Pitt score ≥2 (OR 3.2 (1.8-5.5) and HA-BUTI OR 3.4 (1.2-9.0)). Patients with HCA-BUTI are a specific group with significant clinical and microbiological differences from patients with CA-BUTI, and some similarities with patients with HA-BUTI. Mortality was associated with patient condition, the severity of infection and hospital acquisition.

  1. Clinical features and molecular characteristics of invasive community-acquired methicillin-resistant Staphylococcus aureus infections in Taiwanese children.

    PubMed

    Chen, Chih-Jung; Su, Lin-Hui; Chiu, Cheng-Hsun; Lin, Tzou-Yien; Wong, Kin-Sun; Chen, Yi-Ywan M; Huang, Yhu-Chering

    2007-11-01

    Highly virulent community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) has been associated with morbidity and mortality in various countries of the world. We characterized the clinical and molecular features of pediatric invasive CA-MRSA infections in Taiwan. Between July 2000 and June 2005, 31 previously healthy children with invasive CA-MRSA infections were identified from 423 children with community-onset methicillin-resistant S. aureus infections. The medical records were reviewed. The clinical isolates, if available, were collected for molecular characterization. Sixteen (51.6%) patients were male, and the mean age was 5.7 years. Adolescents accounted for 9 (29%) cases. Eighteen children had bone and/or joint infections, 14 had deep-seated soft tissue infections, 11 had pneumonia, and 2 had central nervous system infections. Multiorgan involvement was identified in 8 of 20 bacteremic cases. Twenty-two patients (71%) required surgical interventions. The mean hospital stay was 27.4 days. All of the 15 available isolates were classified as sequence type (ST) 59 or its single locus variant and belonged to 2 previously reported community-associated clones containing staphylococcal cassette chromosome mec (SCCmec) type IV or type V(T) in Taiwan. Most of the isolates were multiresistant to clindamycin (94%) and erythromycin (97%). Eleven (73.3%) isolates carried pvl genes, and the strains harboring pvl genes were significantly associated with lung involvement. In conclusion, invasive CA-MRSA infections in pediatric population were not limited to young children. Surgical interventions were often required, and a prolonged course of antibiotic therapy was needed. A multiresistant CA-MRSA clone characterized as ST59 was identified from these children in Taiwan. PMID:17662565

  2. Risk factors for infection with multidrug-resistant bacteria in non-ventilated patients with hospital-acquired pneumonia*,**

    PubMed Central

    Seligman, Renato; Ramos-Lima, Luis Francisco; Oliveira, Vivian do Amaral; Sanvicente, Carina; Sartori, Juliana; Pacheco, Elyara Fiorin

    2013-01-01

    OBJECTIVE: To identify risk factors for the development of hospital-acquired pneumonia (HAP) caused by multidrug-resistant (MDR) bacteria in non-ventilated patients. METHODS: This was a retrospective observational cohort study conducted over a three-year period at a tertiary-care teaching hospital. We included only non-ventilated patients diagnosed with HAP and presenting with positive bacterial cultures. Categorical variables were compared with chi-square test. Logistic regression analysis was used to determine risk factors for HAP caused by MDR bacteria. RESULTS: Of the 140 patients diagnosed with HAP, 59 (42.1%) were infected with MDR strains. Among the patients infected with methicillin-resistant Staphylococcus aureus and those infected with methicillin-susceptible S. aureus, mortality was 45.9% and 50.0%, respectively (p = 0.763). Among the patients infected with MDR and those infected with non-MDR gram-negative bacilli, mortality was 45.8% and 38.3%, respectively (p = 0.527). Univariate analysis identified the following risk factors for infection with MDR bacteria: COPD; congestive heart failure; chronic renal failure; dialysis; urinary catheterization; extrapulmonary infection; and use of antimicrobial therapy within the last 10 days before the diagnosis of HAP. Multivariate analysis showed that the use of antibiotics within the last 10 days before the diagnosis of HAP was the only independent predictor of infection with MDR bacteria (OR = 3.45; 95% CI: 1.56-7.61; p = 0.002). CONCLUSIONS: In this single-center study, the use of broad-spectrum antibiotics within the last 10 days before the diagnosis of HAP was the only independent predictor of infection with MDR bacteria in non-ventilated patients with HAP. PMID:23857697

  3. Demography and Intercontinental Spread of the USA300 Community-Acquired Methicillin-Resistant Staphylococcus aureus Lineage

    PubMed Central

    Glaser, Philippe; Martins-Simões, Patrícia; Villain, Adrien; Barbier, Maxime; Tristan, Anne; Bouchier, Christiane; Ma, Laurence; Bes, Michele; Laurent, Frederic; Guillemot, Didier; Wirth, Thierry

    2016-01-01

    ABSTRACT Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) was recognized worldwide during the 1990s; in less than a decade, several genetically distinct CA-MRSA lineages carrying Panton-Valentine leukocidin genes have emerged on every continent. Most notably, in the United States, the sequence type 18-IV (ST8-IV) clone known as USA300 has become highly prevalent, outcompeting methicillin-susceptible S. aureus (MSSA) and other MRSA strains in both community and hospital settings. CA-MRSA bacteria are much less prevalent in Europe, where the European ST80-IV European CA-MRSA clone, USA300 CA-MRSA strains, and other lineages, such as ST22-IV, coexist. The question that arises is whether the USA300 CA-MRSA present in Europe (i) was imported once or on very few occasions, followed by a broad geographic spread, anticipating an increased prevalence in the future, or (ii) derived from multiple importations with limited spreading success. In the present study, we applied whole-genome sequencing to a collection of French USA300 CA-MRSA strains responsible for sporadic cases and micro-outbreaks over the past decade and United States ST8 MSSA and MRSA isolates. Genome-wide phylogenetic analysis demonstrated that the population structure of the French isolates is the product of multiple introductions dating back to the onset of the USA300 CA-MRSA clone in North America. Coalescent-based demography of the USA300 lineage shows that a strong expansion occurred during the 1990s concomitant with the acquisition of the arginine catabolic mobile element and antibiotic resistance, followed by a sharp decline initiated around 2008, reminiscent of the rise-and-fall pattern previously observed in the ST80 lineage. A future expansion of the USA300 lineage in Europe is therefore very unlikely. PMID:26884428

  4. Salicylic acid and systemic acquired resistance play a role in attenuating crown gall disease caused by Agrobacterium tumefaciens.

    PubMed

    Anand, Ajith; Uppalapati, Srinivasa Rao; Ryu, Choong-Min; Allen, Stacy N; Kang, Li; Tang, Yuhong; Mysore, Kirankumar S

    2008-02-01

    We investigated the effects of salicylic acid (SA) and systemic acquired resistance (SAR) on crown gall disease caused by Agrobacterium tumefaciens. Nicotiana benthamiana plants treated with SA showed decreased susceptibility to Agrobacterium infection. Exogenous application of SA to Agrobacterium cultures decreased its growth, virulence, and attachment to plant cells. Using Agrobacterium whole-genome microarrays, we characterized the direct effects of SA on bacterial gene expression and showed that SA inhibits induction of virulence (vir) genes and the repABC operon, and differentially regulates the expression of many other sets of genes. Using virus-induced gene silencing, we further demonstrate that plant genes involved in SA biosynthesis and signaling are important determinants for Agrobacterium infectivity on plants. Silencing of ICS (isochorismate synthase), NPR1 (nonexpresser of pathogenesis-related gene 1), and SABP2 (SA-binding protein 2) in N. benthamiana enhanced Agrobacterium infection. Moreover, plants treated with benzo-(1,2,3)-thiadiazole-7-carbothioic acid, a potent inducer of SAR, showed reduced disease symptoms. Our data suggest that SA and SAR both play a major role in retarding Agrobacterium infectivity. PMID:18156296

  5. Systemic Induction of the Small Antibacterial Compound in the Leaf Exudate During Benzothiadiazole-elicited Systemic Acquired Resistance in Pepper.

    PubMed

    Lee, Boyoung; Park, Yong-Soon; Yi, Hwe-Su; Ryu, Choong-Min

    2013-09-01

    Plants protect themselves from diverse potential pathogens by induction of the immune systems such as systemic acquired resistance (SAR). Most bacterial plant pathogens thrive in the intercellular space (apoplast) of plant tissues and cause symptoms. The apoplastic leaf exudate (LE) is believed to contain nutrients to provide food resource for phytopathogenic bacteria to survive and to bring harmful phytocompounds to protect plants against bacterial pathogens. In this study, we employed the pepper-Xanthomonas axonopodis system to assess whether apoplastic fluid from LE in pepper affects the fitness of X. axonopodis during the induction of SAR. The LE was extracted from pepper leaves 7 days after soil drench-application of a chemical trigger, benzothiadiazole (BTH). Elicitation of plant immunity was confirmed by significant up-regulation of four genes, CaPR1, CaPR4, CaPR9, and CaCHI2, by BTH treatment. Bacterial fitness was evaluated by measuring growth rate during cultivation with LE from BTH- or water-treated leaves. LE from BTH-treatment significantly inhibited bacterial growth when compared to that from the water-treated control. The antibacterial activity of LE from BTH-treated samples was not affected by heating at 100°C for 30 min. Although the antibacterial molecules were not precisely identified, the data suggest that small (less than 5 kDa), heat-stable compound(s) that are present in BTH-induced LE directly attenuate bacterial growth during the elicitation of plant immunity. PMID:25288963

  6. [Multicenter study in southern South America of the in vitro activity of telithromycin in strains with defined resistance phenotypes isolated from community-acquired respiratory infections].

    PubMed

    Casellas, J M; Visser, M; Mac Dougall, N; Coco, B; Tomé, G; Gliosca, L

    2001-09-01

    Telithromycin was the first ketolide to be approved in Europe and is in the approval process in the United States. It is structurally related to the macrolides; it has a keto group in the C3 position rather than cladinose. A carbamate group is also present at C11-C12. As a result, it has a reduced induction of the MLSB resistance mechanism (erm gene), it is not affected by the flux mechanism (mef gene), it has higher stability at low pH and has increased intrinsic activity compared with clarithromycin and azithromycin. Phase III studies have shown telithromycin to be effective in the treatment of community-acquired upper and lower respiratory tract infections. Its long half-life allows for oral once-daily dosing. From a pharmacokinetic point of view, its activity has been shown to be AUC(24h)/MIC dependent. It is active against bacteria involved in atypical pneumonia. The aim of our study was to determine the activity of telithromycin in isolates with defined resistance phenotypes obtained from community-acquired respiratory tract infections. Twelve centers in Argentina, Chile, Paraguay and Uruguay participated in the study. Each center collected three strains of the following species and resistance patterns: S. pyogenes, S. pneumoniae with resistance or intermediate resistance to oxacillin, erythromycin-resistant S. pneumoniae, clindamycin-resistant S. pneumoniae, oxacillin-susceptible S. aureus, erythromycin-resistant S. aureus, ampicillin-susceptible and -resistant M. catarrhalis and H. influenzae. Agar diffusion susceptibility tests with NeoSensitabs tablets (Rosco, Denmark) were carried out at each center. Isolates were sent to the coordinating center, where MICs were determined using agar microdilution and the Seppala test was used to determine the resistance mechanism to macrolides. The 327 isolates received were susceptible to telithromycin. Eighty percent of the erythromycin-resistant S. pneumoniae isolates were likely resistant due to a flux mechanism

  7. Combined use of anti-ErbB monoclonal antibodies and erlotinib enhances antibody-dependent cellular cytotoxicity of wild-type erlotinib-sensitive NSCLC cell lines

    PubMed Central

    2012-01-01

    Background The epidermal growth factor receptor (EGFR) is an established target for anti-cancer treatment in different tumour types. Two different strategies have been explored to inhibit this pivotal molecule in epithelial cancer development: small molecules TKIs and monoclonal antibodies. ErbB/HER-targeting by monoclonal antibodies such as cetuximab and trastuzumab or tyrosine-kinase inhibitors as gefitinib or erlotinib has been proven effective in the treatment of advanced NSCLC. Results In this study we explored the potential of combining either erlotinib with cetuximab or trastuzumab to improve the efficacy of EGFR targeted therapy in EGFR wild-type NSCLC cell lines. Erlotinib treatment was observed to increase EGFR and/or HER2 expression at the plasma membrane level only in NSCLC cell lines sensitive to the drug inducing protein stabilization. The combined treatment had marginal effect on cell proliferation but markedly increased antibody-dependent, NK mediated, cytotoxicity in vitro. Moreover, in the Calu-3 xenograft model, the combination significantly inhibited tumour growth when compared with erlotinib and cetuximab alone. Conclusion Our results indicate that erlotinib increases surface expression of EGFR and/or HER2 only in EGFR-TKI sensitive NSCLC cell lines and, in turns, leads to increased susceptibility to ADCC both in vitro and in a xenograft models. The combination of erlotinib with monoclonal antibodies represents a potential strategy to improve the treatment of wild-type EGFR NSCLC patients sensitive to erlotinib. PMID:23234355

  8. Erlotinib Inhibits Growth of a Patient-Derived Chordoma Xenograft

    PubMed Central

    Siu, I-Mei; Ruzevick, Jacob; Zhao, Qi; Connis, Nick; Jiao, Yuchen; Bettegowda, Chetan; Xia, Xuewei; Burger, Peter C.; Hann, Christine L.; Gallia, Gary L.

    2013-01-01

    Chordomas are rare primary bone tumors that occur along the neuraxis. Primary treatment is surgery, often followed by radiotherapy. Treatment options for patients with recurrence are limited and, notably, there are no FDA approved therapeutic agents. Development of therapeutic options has been limited by the paucity of preclinical model systems. We have established and previously reported the initial characterization of the first patient-derived chordoma xenograft model. In this study, we further characterize this model and demonstrate that it continues to resemble the original patient tumor histologically and immunohistochemically, maintains nuclear expression of brachyury, and is highly concordant with the original patient tumor by whole genome genotyping. Pathway analysis of this xenograft demonstrates activation of epidermal growth factor receptor (EGFR). In vitro studies demonstrate that two small molecule inhibitors of EGFR, erlotinib and gefitinib, inhibit proliferation of the chordoma cell line U-CH 1. We further demonstrate that erlotinib significantly inhibits chordoma growth in vivo. Evaluation of tumors post-treatment reveals that erlotinib reduces phosphorylation of EGFR. This is the first demonstration of antitumor activity in a patient-derived chordoma xenograft model and these findings support further evaluation of EGFR inhibitors in this disease. PMID:24260133

  9. Erlotinib inhibits growth of a patient-derived chordoma xenograft.

    PubMed

    Siu, I-Mei; Ruzevick, Jacob; Zhao, Qi; Connis, Nick; Jiao, Yuchen; Bettegowda, Chetan; Xia, Xuewei; Burger, Peter C; Hann, Christine L; Gallia, Gary L

    2013-01-01

    Chordomas are rare primary bone tumors that occur along the neuraxis. Primary treatment is surgery, often followed by radiotherapy. Treatment options for patients with recurrence are limited and, notably, there are no FDA approved therapeutic agents. Development of therapeutic options has been limited by the paucity of preclinical model systems. We have established and previously reported the initial characterization of the first patient-derived chordoma xenograft model. In this study, we further characterize this model and demonstrate that it continues to resemble the original patient tumor histologically and immunohistochemically, maintains nuclear expression of brachyury, and is highly concordant with the original patient tumor by whole genome genotyping. Pathway analysis of this xenograft demonstrates activation of epidermal growth factor receptor (EGFR). In vitro studies demonstrate that two small molecule inhibitors of EGFR, erlotinib and gefitinib, inhibit proliferation of the chordoma cell line U-CH 1. We further demonstrate that erlotinib significantly inhibits chordoma growth in vivo. Evaluation of tumors post-treatment reveals that erlotinib reduces phosphorylation of EGFR. This is the first demonstration of antitumor activity in a patient-derived chordoma xenograft model and these findings support further evaluation of EGFR inhibitors in this disease.

  10. Multifocal pelvic abscesses and osteomyelitis from community-acquired methicillin-resistant Staphylococcus aureus in a 17-year-old basketball player.

    PubMed

    Okubo, Takeshi; Yabe, Shizuka; Otsuka, Taketo; Takizawa, Yoko; Takano, Tomomi; Dohmae, Soshi; Higuchi, Wataru; Tsukada, Hiroki; Gejyo, Fumitake; Uchiyama, Makoto; Yamamoto, Tatsuo

    2008-03-01

    A 17-year-old female basketball player suffered from cutaneous abscesses, which complicated into a systemic progression to osteomyelitis and simultaneous iliopsoas and piriformis abscesses, adjacent to the sacroiliac joint. The causative agent was community-acquired methicillin-resistant Staphylococcus aureus with multilocus sequence type 30, spa19, and SCCmecIVc. The clinical importance of this genotype is discussed.

  11. Small cell lung cancer transformation and T790M mutation: complimentary roles in acquired resistance to kinase inhibitors in lung cancer.

    PubMed

    Suda, Kenichi; Murakami, Isao; Sakai, Kazuko; Mizuuchi, Hiroshi; Shimizu, Shigeki; Sato, Katsuaki; Tomizawa, Kenji; Tomida, Shuta; Yatabe, Yasushi; Nishio, Kazuto; Mitsudomi, Tetsuya

    2015-09-24

    Lung cancers often harbour a mutation in the epidermal growth factor receptor (EGFR) gene. Because proliferation and survival of lung cancers with EGFR mutation solely depend on aberrant signalling from the mutated EGFR, these tumours often show dramatic responses to EGFR tyrosine kinase inhibitors (TKIs). However, acquiring resistance to these drugs is almost inevitable, thus a better understanding of the underlying resistance mechanisms is critical. Small cell lung cancer (SCLC) transformation is a relatively rare acquired resistance mechanism that has lately attracted considerable attention. In the present study, through an in-depth analysis of multiple EGFR-TKI refractory lesions obtained from an autopsy case, we observed a complementary relationship between SCLC transformation and EGFR T790M secondary mutation (resistance mutation). We also identified analogies and differences in genetic aberration between a TKI-refractory lesion with SCLC transformation and one with EGFR T790M mutation. In particular, target sequencing revealed a TP53 P151S mutation in all pre- and post-treatment lesions. PTEN M264I mutation was identified only in a TKI-refractory lesion with SCLC transformation, while PIK3CA and RB1 mutations were identified only in pre-treatment primary tumour samples. These results provide the groundwork for understanding acquired resistance to EGFR-TKIs via SCLC transformation.

  12. The battle against multi-resistant strains: Renaissance of antimicrobial essential oils as a promising force to fight hospital-acquired infections.

    PubMed

    Warnke, Patrick H; Becker, Stephan T; Podschun, Rainer; Sivananthan, Sureshan; Springer, Ingo N; Russo, Paul A J; Wiltfang, Joerg; Fickenscher, Helmut; Sherry, Eugene

    2009-10-01

    Hospital-acquired infections and antibiotic-resistant bacteria continue to be major health concerns worldwide. Particularly problematic is methicillin-resistant Staphylococcus aureus (MRSA) and its ability to cause severe soft tissue, bone or implant infections. First used by the Australian Aborigines, Tea tree oil and Eucalyptus oil (and several other essential oils) have each demonstrated promising efficacy against several bacteria and have been used clinically against multi-resistant strains. Several common and hospital-acquired bacterial and yeast isolates (6 Staphylococcus strains including MRSA, 4 Streptococcus strains and 3 Candida strains including Candida krusei) were tested for their susceptibility for Eucalyptus, Tea tree, Thyme white, Lavender, Lemon, Lemongrass, Cinnamon, Grapefruit, Clove Bud, Sandalwood, Peppermint, Kunzea and Sage oil with the agar diffusion test. Olive oil, Paraffin oil, Ethanol (70%), Povidone iodine, Chlorhexidine and hydrogen peroxide (H(2)O(2)) served as controls. Large prevailing effective zones of inhibition were observed for Thyme white, Lemon, Lemongrass and Cinnamon oil. The other oils also showed considerable efficacy. Remarkably, almost all tested oils demonstrated efficacy against hospital-acquired isolates and reference strains, whereas Olive and Paraffin oil from the control group produced no inhibition. As proven in vitro, essential oils represent a cheap and effective antiseptic topical treatment option even for antibiotic-resistant strains as MRSA and antimycotic-resistant Candida species. PMID:19473851

  13. Transformation of sweet orange [Citrus sinensis (L.) Osbeck] with pthA-nls for acquiring resistance to citrus canker disease.

    PubMed

    Yang, Li; Hu, Chunhua; Li, Na; Zhang, Jiayin; Yan, Jiawen; Deng, Ziniu

    2011-01-01

    The COOH terminal of pthA encoding three nuclear localizing signals (NLS) was amplified by polymerase chain reaction (PCR) from the plasmid of Xanthomonas axonopodis pv. citri, the pathogen of citrus canker disease. Then the sense and antisense strands of the nls were cloned into pBI121 vector. pthA-nls driven by the CaMV35 s promoter was transferred into sweet orange via Agrobacterium -mediated transformation. Successful integration was confirmed by PCR and Southern blotting, and 12 sense-nls (nls (+)) and 9 antisense-nls (nls (-)) transgenic clones were obtained. The expression of nls fragment was analyzed by RT-PCR, Real time q-PCR and Western blotting, in which the specific NLS protein was detected only in nls (+) transgenic clones. In an in vitro assay, when pin-puncture inoculation was performed with 2.5 × 10(7) cfu/ml of bacterial solution, the nls (+) transgenic clones showed no typical lesion development, while typical symptoms were observed in the wild types and the nls (-) transgenic clones. In vivo assay results indicated that the nls (+) transgenic clones showed less disease incidence, in comparison with the wild types and the nls (-) transgenic clones, when pin-puncture inoculation was performed with 10(4)-10(5) cfu/ml. The minimum disease incidence was 23.3% for 'Sucarri' sweet orange and 33.3% for 'Bingtang' sweet orange. When 10(4)-10(7) cfu/ml of pathogen was spray inoculated, the nls (+) transgenic clones did not show any symptom, and even the concentration raised to 10(9) cfu/ml, the disease incidence was 20-80%, while the wild types and the nls (-) transgenic clones had 100% disease development with whatever concentration of inoculum. Two transgenic clones were confirmed to be resistant to citrus canker disease in the repeated inoculation. The results suggested that the transformation of nls sense strands may offer an effective way to acquire resistance to citrus canker disease.

  14. Arabidopsis TTR1 causes LRR-dependent lethal systemic necrosis, rather than systemic acquired resistance, to Tobacco ringspot virus.

    PubMed

    Nam, Moon; Koh, Serry; Kim, Sung Uk; Domier, Leslie L; Jeon, Jae Heung; Kim, Hong Gi; Lee, Su-Heon; Bent, Andrew F; Moon, Jae Sun

    2011-11-01

    Most Arabidopsis ecotypes display tolerance to the Tobacco ringspot virus (TRSV), but a subset of Arabidopsis ecotypes, including Estland (Est), develop lethal systemic necrosis (LSN), which differs from the localized hypersensitive responses (HRs) or systemic acquired resistance (SAR) characteristic of incompatible reactions. Neither viral replication nor the systemic movement of TRSV was restricted in tolerant or sensitive Arabidopsis ecotypes; therefore, the LSN phenotype shown in the sensitive ecotypes might not be due to viral accumulation. In the present study, we identified the Est TTR1 gene (tolerance to Tobacco ringspot virus 1) encoding a TIR-NBS-LRR protein that controls the ecotype-dependent tolerant/sensitive phenotypes by a map-based cloning method. The tolerant Col-0 ecotype Arabidopsis transformed with the sensitive Est TTR1 allele developed an LSN phenotype upon TRSV infection, suggesting that the Est TTR1 allele is dominant over the tolerant ttr1 allele of Col-0. Multiple sequence alignments of 10 tolerant ecotypes from those of eight sensitive ecotypes showed that 10 LRR amino acid polymorphisms were consistently distributed across the TTR1/ttr1 alleles. Site-directed mutagenesis of these amino acids in the LRR region revealed that two sites, L956S and K1124Q, completely abolished the LSN phenotype. VIGS study revealed that TTR1 is dependent on SGT1, rather than EDS1. The LSN phenotype by TTR1 was shown to be transferred to Nicotiana benthamiana, demonstrating functional conservation of TTR1 across plant families, which are involved in SGT-dependent defense responses, rather than EDS1-dependent signaling pathways.

  15. Arabidopsis TTR1 causes LRR-dependent lethal systemic necrosis, rather than systemic acquired resistance, to Tobacco ringspot virus.

    PubMed

    Nam, Moon; Koh, Serry; Kim, Sung Uk; Domier, Leslie L; Jeon, Jae Heung; Kim, Hong Gi; Lee, Su-Heon; Bent, Andrew F; Moon, Jae Sun

    2011-11-01

    Most Arabidopsis ecotypes display tolerance to the Tobacco ringspot virus (TRSV), but a subset of Arabidopsis ecotypes, including Estland (Est), develop lethal systemic necrosis (LSN), which differs from the localized hypersensitive responses (HRs) or systemic acquired resistance (SAR) characteristic of incompatible reactions. Neither viral replication nor the systemic movement of TRSV was restricted in tolerant or sensitive Arabidopsis ecotypes; therefore, the LSN phenotype shown in the sensitive ecotypes might not be due to viral accumulation. In the present study, we identified the Est TTR1 gene (tolerance to Tobacco ringspot virus 1) encoding a TIR-NBS-LRR protein that controls the ecotype-dependent tolerant/sensitive phenotypes by a map-based cloning method. The tolerant Col-0 ecotype Arabidopsis transformed with the sensitive Est TTR1 allele developed an LSN phenotype upon TRSV infection, suggesting that the Est TTR1 allele is dominant over the tolerant ttr1 allele of Col-0. Multiple sequence alignments of 10 tolerant ecotypes from those of eight sensitive ecotypes showed that 10 LRR amino acid polymorphisms were consistently distributed across the TTR1/ttr1 alleles. Site-directed mutagenesis of these amino acids in the LRR region revealed that two sites, L956S and K1124Q, completely abolished the LSN phenotype. VIGS study revealed that TTR1 is dependent on SGT1, rather than EDS1. The LSN phenotype by TTR1 was shown to be transferred to Nicotiana benthamiana, demonstrating functional conservation of TTR1 across plant families, which are involved in SGT-dependent defense responses, rather than EDS1-dependent signaling pathways. PMID:22057987

  16. Arabidopsis TTR1 Causes LRR-Dependent Lethal Systemic Necrosis, rather than Systemic Acquired Resistance, to Tobacco Ringspot Virus

    PubMed Central

    Nam, Moon; Koh, Serry; Kim, Sung Uk; Domier, Leslie L.; Jeon, Jae Heung; Kim, Hong Gi; Lee, Su-Heon; Bent, Andrew F.; Moon, Jae Sun

    2011-01-01

    Most Arabidopsis ecotypes display tolerance to the Tobacco ringspot virus (TRSV), but a subset of Arabidopsis ecotypes, including Estland (Est), develop lethal systemic necrosis (LSN), which differs from the localized hypersensitive responses (HRs) or systemic acquired resistance (SAR) characteristic of incompatible reactions. Neither viral replication nor the systemic movement of TRSV was restricted in tolerant or sensitive Arabidopsis ecotypes; therefore, the LSN phenotype shown in the sensitive ecotypes might not be due to viral accumulation. In the present study, we identified the Est TTR1 gene (tolerance to Tobacco ringspot virus 1) encoding a TIR-NBS-LRR protein that controls the ecotype-dependent tolerant/sensitive phenotypes by a map-based cloning method. The tolerant Col-0 ecotype Arabidopsis transformed with the sensitive Est TTR1 allele developed an LSN phenotype upon TRSV infection, suggesting that the Est TTR1 allele is dominant over the tolerant ttr1 allele of Col-0. Multiple sequence alignments of 10 tolerant ecotypes from those of eight sensitive ecotypes showed that 10 LRR amino acid polymorphisms were consistently distributed across the TTR1/ttr1 alleles. Site-directed mutagenesis of these amino acids in the LRR region revealed that two sites, L956S and K1124Q, completely abolished the LSN phenotype. VIGS study revealed that TTR1 is dependent on SGT1, rather than EDS1. The LSN phenotype by TTR1 was shown to be transferred to Nicotiana benthamiana, demonstrating functional conservation of TTR1 across plant families, which are involved in SGT-dependent defense responses, rather than EDS1-dependent signaling pathways. PMID:22057987

  17. Induction of the Staphylococcal Proteolytic Cascade by Antimicrobial Fatty Acids in Community Acquired Methicillin Resistant Staphylococcus aureus

    PubMed Central

    Arsic, Benjamin; Zhu, Yue; Heinrichs, David E.; McGavin, Martin J.

    2012-01-01

    Community acquired methicillin resistant Staphylococcus aureus (CA-MRSA), and the USA300 strain of CA-MRSA in particular, are known for their rapid community transmission, and propensity to cause aggressive skin and soft tissue infections. To assess factors that contribute to these hallmark traits of CA-MRSA, we evaluated how growth of USA300 and production of secreted virulence factors was influenced on exposure to physiologic levels of unsaturated free fatty acids that would be encountered on the skin or anterior nares, which represent the first sites of contact with healthy human hosts. There was a sharp threshold between sub-inhibitory and inhibitory concentrations, such that 100 µM sapienic acid (C16∶1) and linoleic acid (C18∶1) were sufficient to prevent growth after 24 h incubation, while 25 µM allowed unrestricted growth, and 50 µM caused an approximate 10–12 h lag, followed by unimpeded exponential growth. Conversely, saturated palmitic or stearic acids did not affect growth at 100 µM. Although growth was not affected by 25 µM sapienic or linoleic acid, these and other unsaturated C16 and C18 fatty acids, but not their saturated counterparts, promoted robust production of secreted proteases comprising the Staphylococcal proteolytic cascade. This trait was also manifested to varying degrees in other CA-MRSA, and in genetically diverse methicillin susceptible S. aureus strains. Therefore, induction of the Staphylococcal proteolytic cascade by unsaturated fatty acids is another feature that should now be evaluated as a potential contributing factor in the aggressive nature of skin and soft tissue infections caused by USA300, and as a general virulence mechanism of S. aureus. PMID:23029337

  18. Intercalated chemotherapy and erlotinib for non-small cell lung cancer (NSCLC) with activating epidermal growth factor receptor (EGFR) mutations

    PubMed Central

    Zwitter, Matjaz; Rajer, Mirjana; Stanic, Karmen; Vrankar, Martina; Doma, Andrej; Cuderman, Anka; Grmek, Marko; Kern, Izidor; Kovac, Viljem

    2016-01-01

    ABSTRACT Among attempts to delay development of resistance to tyrosine kinase inhibitors (TKIs) in patients with advanced non-small cell lung cancer (NSCLC) with activating mutations of epidermal growth factor receptor (EGFR), intercalated therapy has not been properly evaluated. In a phase II trial, 38 patients with EGFR mutated NSCLC in advanced stage were treated with 4 to 6 3-weekly cycles of intercalated schedule with gemcitabine (1250 mg/m2, days 1 and 4), cisplatin (75 mg/m2, day 2) and erlotinib (150 mg, days 5 – 15), followed by continuous erlotinib as maintenance. In addition to standard radiologic evaluation according to RECIST, PET/CT was done prior to treatment and at 6 months, using PERCIST as a method for assessment of response. The primary endpoint was progression-free survival (PFS). In general, tolerance to treatment was good, even among 8 patients with performance status 2–3 and 13 patients with brain metastases; grade 4 toxicity included 2 cases of neutropenia and 4 thrombo-embolic events. Complete response (CR) or partial response (PR) were seen in 15 (39.5%) and 17 (44.7%) cases, respectively. All cases of CR were confirmed also by PET/CT. Median PFS was 23.4 months and median overall survival (OS) was 38.3  months. After a median follow-up of 35 months, 8 patients are still in CR and on maintenance erlotinib. In conclusion, intercalated treatment for treatment-naive patients with EGFR activating mutations leads to excellent response rate and prolonged PFS and survival. Comparison of the intercalated schedule to monotherapy with TKIs in a randomized trial is warranted. PMID:27261103

  19. Overcoming acquired drug resistance in colorectal cancer cells by targeted delivery of 5-FU with EGF grafted hollow mesoporous silica nanoparticles

    NASA Astrophysics Data System (ADS)

    Chen, Lijue; She, Xiaodong; Wang, Tao; He, Li; Shigdar, Sarah; Duan, Wei; Kong, Lingxue

    2015-08-01

    Acquired drug resistance (ADR) can be developed in colorectal cancer cells after 5-fluorouracil (5-FU) treatment and diminish the effectiveness of chemotherapy. In this work, acquired 5-FU resistance in the colorectal cancer cell line SW480 was obtained with the up-regulation of dihydropyrimidine dehydrogenase (DPYD) gene expression which can convert 5-FU to its inactive metabolite. To overcome ADR in colorectal cancer, hollow mesoporous silica nanoparticles (HMSNs) grafted with epidermal growth factor (EGF) were used as nanocarriers to deliver 5-FU to colorectal cancer cells with acquired drug resistance. The effect and mechanism of 5-FU loaded EGF grafted HMSNs (EGF-HMSNs-5-FU) in overcoming acquired drug resistance in SW480/ADR cells were studied. The EGF-HMSNs were demonstrated to be specifically internalized in EGFR overexpressed SW480/ADR cells via a receptor-mediated endocytosis and can escape from endo-lysosomes. The EGF-HMSNs-5-FU exhibited much higher cytotoxicity on SW480/ADR cells than HMSNs-5-FU and free 5-FU while the plain HMSNs did not show significant cytotoxicity. The mechanism of EGF-HMSNs-5-FU in overcoming drug resistance in SW480/ADR cells could be attributed to the specific internalization of EGF-HMSNs-5-FU in EGFR overexpressed cells which can lead to high intracellular drug accumulation and cause cell death through S phase arrest.Acquired drug resistance (ADR) can be developed in colorectal cancer cells after 5-fluorouracil (5-FU) treatment and diminish the effectiveness of chemotherapy. In this work, acquired 5-FU resistance in the colorectal cancer cell line SW480 was obtained with the up-regulation of dihydropyrimidine dehydrogenase (DPYD) gene expression which can convert 5-FU to its inactive metabolite. To overcome ADR in colorectal cancer, hollow mesoporous silica nanoparticles (HMSNs) grafted with epidermal growth factor (EGF) were used as nanocarriers to deliver 5-FU to colorectal cancer cells with acquired drug resistance. The

  20. Insulin-like growth factor-I receptor signalling and acquired resistance to gefitinib (ZD1839; Iressa) in human breast and prostate cancer cells.

    PubMed

    Jones, H E; Goddard, L; Gee, J M W; Hiscox, S; Rubini, M; Barrow, D; Knowlden, J M; Williams, S; Wakeling, A E; Nicholson, R I

    2004-12-01

    De novo and acquired resistance to the anti-tumour drug gefitinib (ZD1839; Iressa), a specific epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) has been reported. We have determined whether signalling through the IGF-I receptor (IGF-1R) pathway plays a role in the gefitinib-acquired resistance phenotype. Continuous exposure of EGFR-positive MCF-7-derived tamoxifen resistant breast cancer cells (TAM-R) to 1 microM gefitinib resulted in a sustained growth inhibition (90%) for 4 months before the surviving cells resumed proliferation. A stable gefitinib-resistant subline (TAM/TKI-R) was established after a further 2 months and this showed no detectable basal phosphorylated EGFR activity. Compared with the parental TAM-R cells, the TAM/ TKI-R cells demonstrated (a) elevated levels of activated IGF-1R, AKT and protein kinase C (PKC)delta, (b) an increased sensitivity to growth inhibition by the IGF-1R TKI AG1024 and (c) an increased migratory capacity that was reduced by AG1024 treatment. Similarly, the EGFR-positive androgen-independent human prostate cancer cell line DU145 was also continuously challenged with 1 microM gefitinib and, although substantial growth inhibition (60%) was seen initially, a gefitinib-resistant variant (DU145/TKI-R) developed after 3 months. Like their breast cancer counterparts, the DU145/TKI-R cells showed increases in the levels of components of the IGF-1R signalling pathway and an elevated sensitivity to growth inhibition by AG1024 compared with the parent DU145 cell line. Additionally, DU145/TKI-R cell migration was also decreased by this inhibitor. We have therefore concluded that in breast and prostate cancer cells acquired resistance to gefitinib is associated with increased signalling via the IGF-1R pathway, which also plays a role in the invasive capacity of the gefitinib-resistant phenotype.

  1. Curcumin mediates oxaliplatin-acquired resistance reversion in colorectal cancer cell lines through modulation of CXC-Chemokine/NF-κB signalling pathway

    PubMed Central

    Ruiz de Porras, Vicenç; Bystrup, Sara; Martínez-Cardús, Anna; Pluvinet, Raquel; Sumoy, Lauro; Howells, Lynne; James, Mark I.; Iwuji, Chinenye; Manzano, José Luis; Layos, Laura; Bugés, Cristina; Abad, Albert; Martínez-Balibrea, Eva

    2016-01-01

    Resistance to oxaliplatin (OXA) is a complex process affecting the outcomes of metastatic colorectal cancer (CRC) patients treated with this drug. De-regulation of the NF-κB signalling pathway has been proposed as an important mechanism involved in this phenomenon. Here, we show that NF-κB was hyperactivated in in vitro models of OXA-acquired resistance but was attenuated by the addition of Curcumin, a non-toxic NF-κB inhibitor. The concomitant combination of Curcumin + OXA was more effective and synergistic in cell lines with acquired resistance to OXA, leading to the reversion of their resistant phenotype, through the inhibition of the NF-κB signalling cascade. Transcriptomic profiling revealed the up-regulation of three NF-κB-regulated CXC-chemokines, CXCL8, CXCL1 and CXCL2, in the resistant cells that were more efficiently down-regulated after OXA + Curcumin treatment as compared to the sensitive cells. Moreover, CXCL8 and CXCL1 gene silencing made resistant cells more sensitive to OXA through the inhibition of the Akt/NF-κB pathway. High expression of CXCL1 in FFPE samples from explant cultures of CRC patients-derived liver metastases was associated with response to OXA + Curcumin. In conclusion, we suggest that combination of OXA + Curcumin could be an effective treatment, for which CXCL1 could be used as a predictive marker, in CRC patients. PMID:27091625

  2. Molecular characterization of anastrozole resistance in breast cancer: pivotal role of the Akt/mTOR pathway in the emergence of de novo or acquired resistance and importance of combining the allosteric Akt inhibitor MK-2206 with an aromatase inhibitor.

    PubMed

    Vilquin, Paul; Villedieu, Marie; Grisard, Evelyne; Ben Larbi, Sabrina; Ghayad, Sandra E; Heudel, Pierre-Etienne; Bachelot, Thomas; Corbo, Laura; Treilleux, Isabelle; Vendrell, Julie A; Cohen, Pascale A

    2013-10-01

    Acquisition of resistance to aromatase inhibitors (AIs) remains a major drawback in the treatment of estrogen receptor alpha (ERα)-positive breast cancers. The Res-Ana cells, a new model of acquired resistance to anastrozole, were established by long-term exposure of aromatase-overexpressing MCF-7 cells to this drug. These resistant cells developed ER-independent mechanisms of resistance and decreased sensitivity to the AI letrozole or to ERα antagonists. They also displayed a constitutive activation of the PI3K/Akt/mTOR pathway and a deregulated expression of several ErbB receptors. An observed increase in the phospho-Akt/Akt ratio between primary and matched recurrent breast tumors of patients who relapsed under anastrozole adjuvant therapy also argued for a pivotal role of the Akt pathway in acquired resistance to anastrozole. Ectopic overexpression of constitutively active Akt1 in control cells was sufficient to induce de novo resistance to anastrozole. Strikingly, combining anastrozole with the highly selective and allosteric Akt inhibitor MK-2206 or with the mTOR inhibitor rapamycin increased sensitivity to this AI in the control cells and was sufficient to overcome resistance and restore sensitivity to endocrine therapy in the resistant cells. Our findings lead to us proposing a model of anastrozole-acquired resistance based on the selection of cancer-initiating-like cells possessing self-renewing properties, intrinsic resistance to anastrozole and sensitivity to MK-2206. Altogether, our work demonstrated that the Akt/mTOR pathway plays a key role in resistance to anastrozole and that combining anastrozole with Akt/mTOR pathway inhibitors represents a promising strategy in the clinical management of hormone-dependent breast cancer patients.

  3. The Role of PIK3CA Mutations among Lung Adenocarcinoma Patients with Primary and Acquired Resistance to EGFR Tyrosine Kinase Inhibition

    PubMed Central

    Wu, Shang-Gin; Chang, Yih-Leong; Yu, Chong-Jen; Yang, Pan-Chyr; Shih, Jin-Yuan

    2016-01-01

    To understand the impact of PIK3CA mutations on clinical characteristics and treatment response to epidermal growth factor tyrosine kinase inhibitors (EGFR TKIs) of lung adenocarcinoma, we examined PIK3CA and EGFR mutations in lung adenocarcinoma patients, and analyzed their clinical outcomes. Surgically excised tumor, bronchoscopy biopsy/brushing specimens and pleural effusions were prospectively collected from 1029 patients. PIK3CA and EGFR mutations were analyzed by RT-PCR and direct sequencing. In EGFR TKI-nave specimens, PIK3CA mutation rate was 1.8% (14/760). Twelve patients had coexisting PIK3CA and EGFR mutations. Among the 344 EGFR TKI-treated EGFR mutant patients, there was no significant difference in treatment response (p = 0.476) and progression-free survival (p = 0.401) of EGFR TKI between PIK3CA mutation-positive and negative patients. The PIK3CA mutation rate in lung adenocarcinoma with acquired resistance to EGFR TKI is not higher than that in EGFR TKI-naïve tissue specimens (2.9% (6/207) vs. 1.8%; p = 0.344). Of the 74 patients with paired specimens (TKI-naïve and acquired resistance to TKIs) only one patient (1.4%) developed acquired PIK3CA (E545K) mutation, and he also had acquired EGFR (T790M) mutation. In conclusion, PIK3CA mutation may not be associated with primary resistance to EGFR TKI among lung adenocarcinoma patients. Acquired PIK3CA mutation related to EGFR TKI treatment is rare. PMID:27734950

  4. Hypermorphic mutation of phospholipase C, γ2 acquired in ibrutinib-resistant CLL confers BTK independency upon B-cell receptor activation

    PubMed Central

    Liu, Ta-Ming; Woyach, Jennifer A.; Zhong, Yiming; Lozanski, Arletta; Lozanski, Gerard; Dong, Shuai; Strattan, Ethan; Lehman, Amy; Zhang, Xiaoli; Jones, Jeffrey A.; Flynn, Joseph; Andritsos, Leslie A.; Maddocks, Kami; Jaglowski, Samantha M.; Blum, Kristie A.; Byrd, John C.; Dubovsky, Jason A.

    2015-01-01

    Ibrutinib has significantly improved the outcome of patients with relapsed chronic lymphocytic leukemia (CLL). Recent reports attribute ibrutinib resistance to acquired mutations in Bruton agammaglobulinemia tyrosine kinase (BTK), the target of ibrutinib, as well as the immediate downstream effector phospholipase C, γ2 (PLCG2). Although the C481S mutation found in BTK has been shown to disable ibrutinib’s capacity to irreversibly bind this primary target, the detailed mechanisms of mutations in PLCG2 have yet to be established. Herein, we characterize the enhanced signaling competence, BTK independence, and surface immunoglobulin dependence of the PLCG2 mutation at R665W, which has been documented in ibrutinib-resistant CLL. Our data demonstrate that this missense alteration elicits BTK-independent activation after B-cell receptor engagement, implying the formation of a novel BTK-bypass pathway. Consistent with previous results, PLCG2R665W confers hypermorphic induction of downstream signaling events. Our studies reveal that proximal kinases SYK and LYN are critical for the activation of mutant PLCG2 and that therapeutics targeting SYK and LYN can combat molecular resistance in cell line models and primary CLL cells from ibrutinib-resistant patients. Altogether, our results engender a molecular understanding of the identified aberration at PLCG2 and explore its functional dependency on BTK, SYK, and LYN, suggesting alternative strategies to combat acquired ibrutinib resistance. PMID:25972157

  5. Multiplicity of acquired cross-resistance in paclitaxel-resistant cancer cells is associated with feedback control of TUBB3 via FOXO3a-mediated ABCB1 regulation

    PubMed Central

    Aldonza, Mark Borris D.; Hong, Ji-Young; Alinsug, Malona V.; Song, Jayoung; Lee, Sang Kook

    2016-01-01

    Acquired drug resistance is a primary obstacle for effective cancer therapy. The correlation of point mutations in class III β-tubulin (TUBB3) and the prominent overexpression of ATP-binding cassette P-glycoprotein (ABCB1), a multidrug resistance gene, have been protruding mechanisms of resistance to microtubule disruptors such as paclitaxel (PTX) for many cancers. However, the precise underlying mechanism of the rapid onset of cross-resistance to an array of structurally and functionally unrelated drugs in PTX-resistant cancers has been poorly understood. We determined that our established PTX-resistant cancer cells display ABCB1/ABCC1-associated cross-resistance to chemically different drugs such as 5-fluorouracil, docetaxel, and cisplatin. We found that feedback activation of TUBB3 can be triggered through the FOXO3a-dependent regulation of ABCB1, which resulted in the accentuation of induced PTX resistance and encouraged multiplicity in acquired cross-resistance. FOXO3a-directed regulation of P-glycoprotein (P-gp) function suggests that control of ABCB1 involves methylation-dependent activation. Consistently, transcriptional overexpression or downregulation of FOXO3a directs inhibitor-controlled protease-degradation of TUBB3. The functional PI3K/Akt signaling is tightly responsive to FOXO3a activation alongside doxorubicin treatment, which directs FOXO3a arginine hypermethylation. In addition, we found that secretome factors from PTX-resistant cancer cells with acquired cross-resistance support a P-gp-dependent association in multidrug resistance (MDR) development, which assisted the FOXO3a-mediated control of TUBB3 feedback. The direct silencing of TUBB3 reverses induced multiple cross-resistance, reduces drug-resistant tumor mass, and suppresses the impaired microtubule stability status of PTX-resistant cells with transient cross-resistance. These findings highlight the control of the TUBB3 response to ABCB1 genetic suppressors as a mechanism to reverse the

  6. Multidrug-resistant North American pulsotype 2 Clostridium difficile was the predominant toxigenic hospital-acquired strain in the province of Manitoba, Canada, in 2006-2007.

    PubMed

    Karlowsky, James A; Zhanel, George G; Hammond, Greg W; Rubinstein, Ethan; Wylie, John; Du, Tim; Mulvey, Michael R; Alfa, Michelle J

    2012-05-01

    The objective of the current study was to determine whether the antimicrobial susceptibility profile or genotype of hospital-acquired isolates of Clostridium difficile differed from isolates causing community-acquired disease. Five hundred diarrhoeal stool samples (one >2 ml sample per patient) from patients across Manitoba, Canada, in 2006-2007 that were reported as C. difficile toxin positive were cultured, resulting in 432 isolates of toxin-positive C. difficile for analysis. Of these 432 isolates, acquisition status could be determined for 235 (54.4%); 182 (77.4%) isolates were hospital acquired and 53 (22.6%) were community acquired. North American pulsotype (NAP) designations based on SmaI PFGE could be defined for 52.3% of the 432 isolates, with NAP2 (n=122) being the most common. Ninety-one per cent (71/78) of NAP2 isolates were recovered from patients with hospital-acquired C. difficile disease. Other NAP types and isolates with non-NAP-type PFGE patterns were less frequently associated with hospital-acquired disease. Community-acquired disease (35.3% of isolates) was associated with a wide variety of NAP types. NAP2 isolates were homogeneous (85.5% had SmaI PFGE pattern 0003) and demonstrated low susceptibility to moxifloxacin (6.6%) and clindamycin (1.6%) compared with non-NAP2 isolates (64.1-93.2% moxifloxacin susceptible; 14.1-28.2% clindamycin susceptible). All isolates of C. difficile in Manitoba were susceptible to metronidazole, piperacillin-tazobactam, amoxicillin-clavulanate and meropenem. NAP2 isolates of toxigenic C. difficile were approximately three times more common than NAP1 isolates (28.2 vs 9.1%) in Manitoba in 2006-2007, and these isolates demonstrated high levels of clonality and multidrug resistance, and were associated with hospital acquisition. PMID:22301615

  7. Erlotinib exhibits antineoplastic off-target effects in AML and MDS: a preclinical study.

    PubMed

    Boehrer, Simone; Adès, Lionel; Braun, Thorsten; Galluzzi, Lorenzo; Grosjean, Jennifer; Fabre, Claire; Le Roux, Génèviève; Gardin, Claude; Martin, Antoine; de Botton, Stéphane; Fenaux, Pierre; Kroemer, Guido

    2008-02-15

    Erlotinib, an inhibitor of the epidermal growth factor receptor (EGFR), induces differentiation, cell-cycle arrest, and apoptosis of EGFR-negative myeloblasts of patients with myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML), as well as in EGFR-negative cell lines representing these diseases (P39, KG-1, and HL 60). This off-target effect can be explained by inhibitory effects on JAK2. Apoptosis induction coupled to mitochondrial membrane permeabilization occurred independently from phenotypic differentiation. In apoptosis-sensitive AML cells, erlotinib caused a rapid (within less than 1 hour) nucleocytoplasmic translocation of nucleophosmin-1 (NPM-1) and p14(ARF). Apoptosis-insensitive myeloblasts failed to manifest this translocation yet became sensitive to apoptosis induction by erlotinib when NPM-1 was depleted by RNA interference. Moreover, erlotinib reduced the growth of xenografted human AML cells in vivo. Erlotinib also killed CD34(+) bone marrow blasts from MDS and AML patients while sparing normal CD34(+) progenitors. This ex vivo therapeutic effect was once more associated with the nucleocytoplasmic translocation of NPM-1 and p14(ARF). One patient afflicted with both MDS and non-small cell lung cancer manifested hematologic improvement in response to erlotinib. In summary, we here provide novel evidence in vitro, ex vivo, and in vivo for the potential therapeutic efficacy of erlotinib in the treatment of high-risk MDS and AML.

  8. Inhibition of STAT3 by Niclosamide Synergizes with Erlotinib against Head and Neck Cancer

    PubMed Central

    Li, Rui; You, Shuo; Hu, Zhongliang; Chen, Zhuo G.; Sica, Gabriel L.; Khuri, Fadlo R.; Curran, Walter J.; Shin, Dong M.; Deng, Xingming

    2013-01-01

    Epidermal growth factor receptor (EGFR) is extensively expressed in head and neck cancer. However, EGFR-targeted therapy has only modest efficacy in head and neck cancer, through mechanisms that are not fully understood. Here, we found that inhibition of EGFR by erlotinib stimulated phosphorylation and activation of STAT3 leading to increased Bcl2/Bcl-XL expression in head and neck cancer cells, which may dampen the therapeutic efficacy of erlotinib against head and neck cancer. Erlotinib-enhanced STAT3 phosphorylation results, at least in part, from suppression of its physiological phosphatase, PTPMeg2. Specific knockdown of STAT3 by RNA interference significantly sensitized head and neck cancer cells to erlotinib treatment. Pharmacological inhibition of STAT3 by niclosamide not only blocked erlotinib-stimulated STAT3 phosphorylation but also synergistically repressed head and neck cancer growth in vitro and in vivo. Combined inhibition of EGFR and STAT3 by erlotinib and niclosamide more effectively induced apoptosis in tumor tissues without toxicity for normal tissues. Based on our findings, treatment with erlotinib combined with niclosamide may offer an effective therapeutic approach to improve the prognosis of head and neck cancer. PMID:24019973

  9. Upregulation of Mucin4 in ER-positive/HER2-Overexpressing Breast Cancer Xenografts with Acquired Resistance to Endocrine and HER2-Targeted Therapies

    PubMed Central

    Chen, Albert C.; Migliaccio, Ilenia; Rimawi, Mothaffar; Lopez-Tarruella, Sara; Creighton, Chad J.; Massarweh, Suleiman; Huang, Catherine; Wang, Yen-Chao; Batra, Surinder K.; Gutierrez, M. Carolina; Osborne, C. Kent; Schiff, Rachel

    2012-01-01

    Background We studied resistance to endocrine and HER2-targeted therapies using a xenograft model of estrogen receptor positive (ER)/HER2-overexpressing breast cancer. Here, we report a novel phenotype of drug resistance in this model. Methods MCF7/HER2-18 xenografts were treated with endocrine therapy alone or in combination with lapatinib and trastuzumab (LT) to inhibit HER2. Archival tumor tissues were stained with hematoxylin & eosin and mucicarmine. RNA extracted from tumors at early time points and late after acquired resistance were analyzed for mucin4 (MUC4) expression by microarray and quantitative reverse transcriptase-PCR. Protein expression of the MUC4, ER and HER2 signaling pathways was measured by immunohistochemistry and Western blotting. Results The combination of the potent anti-HER2 regimen LT with either tamoxifen (Tam+LT) or estrogen deprivation (ED+LT) can cause complete eradication of ER-positive/HER2-overexpressing tumors in mice. Tumors developing resistance to this combination, as well as those acquiring resistance to endocrine therapy alone, exhibited a distinct histological and molecular phenotype—a striking increase in mucin-filled vacuoles and upregulation of several mucins including MUC4. At the onset of resistance, MUC4 mRNA and protein were increased. These tumors also showed upregulation and reactivation of HER2 signaling, while losing ER protein and the estrogen-regulated gene, progesterone receptor. Conclusions Mucins are upregulated in a preclinical model of ER-positive/HER2-overexpressing breast cancer as resistance develops to the combination of endocrine and anti-HER2 therapy. These mucin-rich tumors reactivate the HER2 pathway and shift their molecular phenotype to become more ER-negative/HER2-positive. PMID:22644656

  10. The BIM deletion polymorphism: A paradigm of a permissive interaction between germline and acquired TKI resistance factors in chronic myeloid leukemia.

    PubMed

    Ko, Tun Kiat; Chin, Hui San; Chuah, Charles T H; Huang, John W J; Ng, King-Pan; Khaw, Seong Lin; Huang, David C S; Ong, S Tiong

    2016-01-19

    Both germline polymorphisms and tumor-specific genetic alterations can determine the response of a cancer to a given therapy. We previously reported a germline deletion polymorphism in the BIM gene that was sufficient to mediate intrinsic resistance to tyrosine kinase inhibitors (TKI) in chronic myeloid leukemia (CML), as well as other cancers [1]. The deletion polymorphism favored the generation of BIM splice forms lacking the pro-apoptotic BH3 domain, conferring a relative resistance to the TKI imatinib (IM). However, CML patients with the BIM deletion polymorphism developed both partial and complete IM resistance. To understand the mechanisms underlying the latter, we grew CML cells either with or without the BIM deletion polymorphism in increasing IM concentrations. Under these conditions, the BIM deletion polymorphism enhanced the emergence of populations with complete IM resistance, mimicking the situation in patients. Importantly, the combined use of TKIs with the BH3 mimetic ABT-737 overcame the BCR-ABL1-dependent and -independent resistance mechanisms found in these cells. Our results illustrate the interplay between germline and acquired genetic factors in confering TKI resistance, and suggest a therapeutic strategy for patients with complete TKI resistance associated with the BIM deletion polymorphism.

  11. Conclusions of the expert panel: importance of erlotinib as a second-line therapeutic option

    PubMed Central

    Castagnari, Aldo

    2008-01-01

    During the Experts Meeting on Lung Cancer, participants emphasized the usefulness of erlotinib as second-line therapy for lung cancer. They noted that, although there are no comparative studies, erlotinib could be as effective as docetaxel and pemetrexed in second-line therapy. Regarding the toxicity profile of each of these drugs – one of the key issues considered in the meeting – specialists pointed out how important it is to clearly identify existing differences in this issue. Each drug has different degrees of toxicity, and this information is crucial at the time of choosing the therapeutic regimen. Erlotinib treatment could be an effective option for second-line therapy. PMID:18831720

  12. Metformin and erlotinib synergize to inhibit basal breast cancer.

    PubMed

    Lau, Ying-Ka Ingar; Du, Xing; Rayannavar, Vinayak; Hopkins, Benjamin; Shaw, Jacquelyn; Bessler, Eliana; Thomas, Tiffany; Pires, Maira M; Keniry, Megan; Parsons, Ramon E; Cremers, Serge; Szabolcs, Matthias; Maurer, Matthew A

    2014-11-15

    Basal-like breast cancers (BBCs) are enriched for increased EGFR expression and decreased expression of PTEN. We found that treatment with metformin and erlotinib synergistically induced apoptosis in a subset of BBC cell lines. The drug combination led to enhanced reduction of EGFR, AKT, S6 and 4EBP1 phosphorylation, as well as prevented colony formation and inhibited mammosphere outgrowth. Our data with other compounds suggested that biguanides combined with EGFR inhibitors have the potential to outperform other targeted drug combinations and could be employed in other breast cancer subtypes, as well as other tumor types, with activated EGFR and PI3K signaling. Analysis of BBC cell line alterations led to the hypothesis that loss of PTEN sensitized cells to the drug combination which was confirmed using isogenic cell line models with and without PTEN expression. Combined metformin and erlotinib led to partial regression of PTEN-null and EGFR-amplified xenografted MDA-MB-468 BBC tumors with evidence of significant apoptosis, reduction of EGFR and AKT signaling, and lack of altered plasma insulin levels. Combined treatment also inhibited xenografted PTEN null HCC-70 BBC cells. Measurement of trough plasma drug levels in xenografted mice and a separately performed pharmacokinetics modeling study support possible clinical translation. PMID:25361177

  13. Evolution of amoxicillin/clavulanate in the treatment of adults with acute bacterial rhinosinusitis and community-acquired pneumonia in response to antimicrobial-resistance patterns.

    PubMed

    File, Thomas M; Benninger, Michael S; Jacobs, Michael R

    2004-06-01

    Current treatment guidelines for community-acquired respiratory tract infections no longer depend solely on the characteristics of the patient and the clinical syndrome, but on those of the offending pathogen, including presence and level of antimicrobial resistance. The most common respiratory tract pathogens known to cause acute bacterial rhinosinusitis (ABRS) and community-acquired pneumonia (CAP) include Streptococcus pneumoniae and Haemophilus influenzae. The prevalence of antimicrobial resistance, especially b-lactum and macrolide resistance, among S pneumoniae and H influenzae has increased dramatically during the past 2 decades, diminishing the activity of many older antimicrobials against resistant organisms. A pharmacokinetically enhanced formulation of amoxicillin/clavulanate has been developed to fulfill the need for an oral b-lactam antimicrobial that achieves a greater time that the serum drug concentration exceeds the minimum inhibitory concentration (T > MIC) of antimicrobials against pathogens than conventional formulations to improve activity against S pneumoniae with reduced susceptibility to penicillin. The b-lactamase inhibitor clavulanate allows for coverage of b-lactamase-producing pathogens, such as H influenzae and M catarrhalis. This article reviews the rationale for, and evolution of, oral amoxicillin clavulanate for ABRS and CAP

  14. Low Incidence of HIV-1C Acquired Drug Resistance 10 Years after Roll-Out of Antiretroviral Therapy in Ethiopia: A Prospective Cohort Study.

    PubMed

    Mulu, Andargachew; Maier, Melanie; Liebert, Uwe Gerd

    2015-01-01

    The emergence of HIV-1 drug resistance mutations has mainly been linked to the duration and composition of antiretroviral treatment (ART), as well as the level of adherence. This study reports the incidence and pattern of acquired antiretroviral drug resistance mutations and long-term outcomes of ART in a prospective cohort from Northwest Ethiopia. Two hundred and twenty HIV-1C infected treatment naïve patients were enrolled and 127 were followed-up for up to 38 months on ART. ART initiation and patients' monitoring was based on the WHO clinical and immunological parameters. HIV viral RNA measurement and drug resistance genotyping were done at baseline (N = 160) and after a median time of 30 (IQR, 27-38) months on ART (N = 127). Viral suppression rate (HIV RNA levels ≤ 400 copies/ml) after a median time of 30 months on ART was found to be 88.2% (112/127), which is in the range for HIV drug resistance prevention suggested by WHO. Of those 15 patients with viral load >400 copies/ml, six harboured one or more drug resistant associated mutations in the reverse transcriptase (RT) region. Observed NRTIs resistance associated mutations were the lamivudine-induced mutation M184V (n = 4) and tenofovir associated mutation K65R (n = 1). The NNRTIs resistance associated mutations were K103N (n = 2), V106M, Y181S, Y188L, V90I, K101E and G190A (n = 1 each). Thymidine analogue mutations and major drug resistance mutations in the protease (PR) region were not detected. Most of the patients (13/15) with virologic failure and accumulated drug resistance mutations had not met the WHO clinical and/or immunological failure criteria and continued the failing regimen. The incidence and pattern of acquired antiretroviral drug resistance mutations is lower and less complex than previous reports from sub Saharan Africa countries. Nevertheless, the data suggest the need for virological monitoring and resistance testing for early detection of failure. Moreover, adherence reinforcement will

  15. FDG-PET is a good biomarker of both early response and acquired resistance in BRAFV600 mutant melanomas treated with vemurafenib and the MEK inhibitor GDC-0973

    PubMed Central

    2012-01-01

    Background The BRAF inhibitor, vemurafenib, has recently been approved for the treatment of metastatic melanoma in patients harboring BRAFV600 mutations. Currently, dual BRAF and MEK inhibition are ongoing in clinical trials with the goal of overcoming the acquired resistance that has unfortunately developed in some vemurafenib patients. FDG-PET measures of metabolic activity are increasingly employed as a pharmacodynamic biomarker for guiding single-agent or combination therapies by gauging initial drug response and monitoring disease progression. However, since tumors are inherently heterogeneous, investigating the effects of BRAF and MEK inhibition on FDG uptake in a panel of different melanomas could help interpret imaging outcomes. Methods 18 F-FDG uptake was measured in vitro in cells with wild-type and mutant (V600) BRAF, and in melanoma cells with an acquired resistance to vemurafenib. We treated the cells with vemurafenib alone or in combination with MEK inhibitor GDC-0973. PET imaging was used in mice to measure FDG uptake in A375 melanoma xenografts and in A375 R1, a vemurafenib-resistant derivative. Histological and biochemical studies of glucose transporters, the MAPK and glycolytic pathways were also undertaken. Results We demonstrate that vemurafenib is equally effective at reducing FDG uptake in cell lines harboring either heterozygous or homozygous BRAFV600 but ineffective in cells with acquired resistance or having WT BRAF status. However, combination with GDC-0973 results in a highly significant increase of efficacy and inhibition of FDG uptake across all twenty lines. Drug-induced changes in FDG uptake were associated with altered levels of membrane GLUT-1, and cell lines harboring RAS mutations displayed enhanced FDG uptake upon exposure to vemurafenib. Interestingly, we found that vemurafenib treatment in mice bearing drug-resistant A375 xenografts also induced increased FDG tumor uptake, accompanied by increases in Hif-1α, Sp1 and Ksr

  16. New findings on primary and acquired resistance to anti-EGFR therapy in metastatic colorectal cancer: do all roads lead to RAS?

    PubMed

    Bronte, Giuseppe; Silvestris, Nicola; Castiglia, Marta; Galvano, Antonio; Passiglia, Francesco; Sortino, Giovanni; Cicero, Giuseppe; Rolfo, Christian; Peeters, Marc; Bazan, Viviana; Fanale, Daniele; Giordano, Antonio; Russo, Antonio

    2015-09-22

    Anti-epidermal growth factor receptor therapy with the monoclonal antibodies cetuximab and panitumumab is the main targeted treatment to combine with standard chemotherapy for metastatic colorectal cancer. Many clinical studies have shown the benefit of the addition of these agents for patients without mutations in the EGFR pathway. Many biomarkers, including KRAS and NRAS mutations, BRAF mutations, PIK3CA mutations, PTEN loss, AREG and EREG expression, and HER-2 amplification have already been identified to select responders to anti-EGFR agents. Among these alterations KRAS and NRAS mutations are currently recognized as the best predictive factors for primary resistance. Liquid biopsy, which helps to isolate circulating tumor DNA, is an innovative method to study both primary and acquired resistance to anti-EGFR monoclonal antibodies. However, high-sensitivity techniques should be used to enable the identification of a wide set of gene mutations related to resistance.

  17. New findings on primary and acquired resistance to anti-EGFR therapy in metastatic colorectal cancer: do all roads lead to RAS?

    PubMed Central

    Castiglia, Marta; Galvano, Antonio; Passiglia, Francesco; Sortino, Giovanni; Cicero, Giuseppe; Rolfo, Christian; Peeters, Marc; Bazan, Viviana; Fanale, Daniele; Giordano, Antonio; Russo, Antonio

    2015-01-01

    Anti-epidermal growth factor receptor therapy with the monoclonal antibodies cetuximab and panitumumab is the main targeted treatment to combine with standard chemotherapy for metastatic colorectal cancer. Many clinical studies have shown the benefit of the addition of these agents for patients without mutations in the EGFR pathway. Many biomarkers, including KRAS and NRAS mutations, BRAF mutations, PIK3CA mutations, PTEN loss, AREG and EREG expression, and HER-2 amplification have already been identified to select responders to anti-EGFR agents. Among these alterations KRAS and NRAS mutations are currently recognized as the best predictive factors for primary resistance. Liquid biopsy, which helps to isolate circulating tumor DNA, is an innovative method to study both primary and acquired resistance to anti-EGFR monoclonal antibodies. However, high-sensitivity techniques should be used to enable the identification of a wide set of gene mutations related to resistance. PMID:26318427

  18. Knockout analysis of Arabidopsis transcription factors TGA2, TGA5, and TGA6 reveals their redundant and essential roles in systemic acquired resistance.

    PubMed

    Zhang, Yuelin; Tessaro, Mark J; Lassner, Michael; Li, Xin

    2003-11-01

    Arabidopsis nonexpresser of pathogenesis-related (PR) genes (NPR1) is the sole positive regulator that has been shown to be essential for the induction of systemic acquired resistance. In npr1 mutant plants, salicylic acid (SA)-mediated PR gene expression and pathogen resistance are abolished completely. NPR1 has been shown to interact with three closely related TGA transcription factors-TGA2, TGA5, and TGA6-in yeast two-hybrid assays. To elucidate the biological functions of these three TGA transcription factors, we analyzed single and combined deletion knockout mutants of TGA2, TGA5, and TGA6 for SA-induced PR gene expression and pathogen resistance. Induction of PR gene expression and pathogen resistance by the SA analog 2,6-dichloroisonicotinic acid (INA) was blocked in tga6-1 tga2-1 tga5-1 but not in tga6-1 or tga2-1 tga5-1 plants. Loss of INA-induced resistance to Peronospora parasitica Noco2 cosegregated with the tga6-1 mutation in progeny of multiple lines that were heterozygous for tga6-1 and homozygous for tga2-1 tga5-1 and could be complemented by genomic clones of wild-type TGA2 or TGA5, indicating that TGA2, TGA5, and TGA6 encode redundant and essential functions in the positive regulation of systemic acquired resistance. In addition, tga6-1 tga2-1 tga5-1 plants had reduced tolerance to high levels of SA and accumulated higher basal levels of PR-1 under noninducing conditions, suggesting that these TGA factors also are important for SA tolerance and the negative regulation of the basal expression of PR-1. PMID:14576289

  19. National and Regional Assessment of Antimicrobial Resistance among Community-Acquired Respiratory Tract Pathogens Identified in a 2005-2006 U.S. Faropenem Surveillance Study▿

    PubMed Central

    Critchley, Ian A.; Brown, Steven D.; Traczewski, Maria M.; Tillotson, Glenn S.; Janjic, Nebojsa

    2007-01-01

    Surveillance studies conducted in the United States over the last decade have revealed increasing resistance among community-acquired respiratory pathogens, especially Streptococcus pneumoniae, that may limit future options for empirical therapy. The objective of this study was to assess the scope and magnitude of the problem at the national and regional levels during the 2005-2006 respiratory season (the season when community-acquired respiratory pathogens are prevalent) in the United States. Also, since faropenem is an oral penem being developed for the treatment of community-acquired respiratory tract infections, another study objective was to provide baseline data to benchmark changes in the susceptibility of U.S. respiratory pathogens to the drug in the future. The in vitro activities of faropenem and other agents were determined against 1,543 S. pneumoniae isolates, 978 Haemophilus influenzae isolates, and 489 Moraxella catarrhalis isolates collected from 104 U.S. laboratories across six geographic regions during the 2005-2006 respiratory season. Among S. pneumoniae isolates, the rates of resistance to penicillin, amoxicillin-clavulanate, and cefdinir were 16, 6.4, and 19.2%, respectively. The least effective agents were trimethoprim-sulfamethoxazole (SXT) and azithromycin, with resistance rates of 23.5 and 34%, respectively. Penicillin resistance rates for S. pneumoniae varied by region (from 8.7 to 22.5%), as did multidrug resistance rates for S. pneumoniae (from 8.8 to 24.9%). Resistance to β-lactams, azithromycin, and SXT was higher among S. pneumoniae isolates from children than those from adults. β-Lactamase production rates among H. influenzae and M. catarrhalis isolates were 27.4 and 91.6%, respectively. Faropenem MICs at which 90% of isolates are inhibited were 0.5 μg/ml for S. pneumoniae, 1 μg/ml for H. influenzae, and 0.5 μg/ml for M. catarrhalis, suggesting that faropenem shows promise as a treatment option for respiratory infections caused

  20. National and regional assessment of antimicrobial resistance among community-acquired respiratory tract pathogens identified in a 2005-2006 U.S. Faropenem surveillance study.

    PubMed

    Critchley, Ian A; Brown, Steven D; Traczewski, Maria M; Tillotson, Glenn S; Janjic, Nebojsa

    2007-12-01

    Surveillance studies conducted in the United States over the last decade have revealed increasing resistance among community-acquired respiratory pathogens, especially Streptococcus pneumoniae, that may limit future options for empirical therapy. The objective of this study was to assess the scope and magnitude of the problem at the national and regional levels during the 2005-2006 respiratory season (the season when community-acquired respiratory pathogens are prevalent) in the United States. Also, since faropenem is an oral penem being developed for the treatment of community-acquired respiratory tract infections, another study objective was to provide baseline data to benchmark changes in the susceptibility of U.S. respiratory pathogens to the drug in the future. The in vitro activities of faropenem and other agents were determined against 1,543 S. pneumoniae isolates, 978 Haemophilus influenzae isolates, and 489 Moraxella catarrhalis isolates collected from 104 U.S. laboratories across six geographic regions during the 2005-2006 respiratory season. Among S. pneumoniae isolates, the rates of resistance to penicillin, amoxicillin-clavulanate, and cefdinir were 16, 6.4, and 19.2%, respectively. The least effective agents were trimethoprim-sulfamethoxazole (SXT) and azithromycin, with resistance rates of 23.5 and 34%, respectively. Penicillin resistance rates for S. pneumoniae varied by region (from 8.7 to 22.5%), as did multidrug resistance rates for S. pneumoniae (from 8.8 to 24.9%). Resistance to beta-lactams, azithromycin, and SXT was higher among S. pneumoniae isolates from children than those from adults. beta-Lactamase production rates among H. influenzae and M. catarrhalis isolates were 27.4 and 91.6%, respectively. Faropenem MICs at which 90% of isolates are inhibited were 0.5 mug/ml for S. pneumoniae, 1 mug/ml for H. influenzae, and 0.5 mug/ml for M. catarrhalis, suggesting that faropenem shows promise as a treatment option for respiratory infections

  1. Diffuse alveolar hemorrhage after erlotinib combined with concurrent chemoradiotherapy in a patient with esophageal carcinoma.

    PubMed

    Zhao, Chuan-Hua; Liu, Rong-Rui; Lin, Li; Liu, Jian-Zhi; Ge, Fei-Jiao; Li, Shan-Shan; Ye, Chen-Yang; Chen, Yu-Ling; Wang, Yan; Xu, Jian-Ming

    2014-01-01

    Diffuse alveolar hemorrhage (DAH) is a life-threatening clinical pathologic syndrome caused by a variety of diseases. We report a case of DAH related to combination therapy of chemoradiotherapy and erlotinib. As to know, DAH following chemoradiotherapy was only reported among hematopoietic stem cell transplant recipients with hematologic malignancies till now. DAH associated with chemoradiotherapy for oesophageal carcinoma has not been reported. This is the first DAH report on erlotinib-combined chemoradiotherapy for esophageal cancer. The authors believe epidermal growth factor receptor tyrosine kinase inhibitor erlotinib increased the lung injury. Molecular targeted drugs are gradually applied to be combined with chemoradiation, whether this combination will cause the increase of serious adverse reactions need further study. This case can provide certain reference for erlotinib in the treatment. Meanwhile, after long term hormone therapy for DAH, the patient was diagnosed with pneumocystis carinii pneumonia. It reminds us to attach importance to the immunosuppressive diseases after long-term hormone treatment.

  2. Modulation of cell metabolic pathways and oxidative stress signaling contribute to acquired melphalan resistance in multiple myeloma cells.

    PubMed

    Zub, Kamila Anna; Sousa, Mirta Mittelstedt Leal de; Sarno, Antonio; Sharma, Animesh; Demirovic, Aida; Rao, Shalini; Young, Clifford; Aas, Per Arne; Ericsson, Ida; Sundan, Anders; Jensen, Ole Nørregaard; Slupphaug, Geir

    2015-01-01

    Alkylating agents are widely used chemotherapeutics in the treatment of many cancers, including leukemia, lymphoma, multiple myeloma, sarcoma, lung, breast and ovarian cancer. Melphalan is the most commonly used chemotherapeutic agent against multiple myeloma. However, despite a 70-80% initial response rate, virtually all patients eventually relapse due to the emergence of drug-resistant tumour cells. By using global proteomic and transcriptomic profiling on melphalan sensitive and resistant RPMI8226 cell lines followed by functional assays, we discovered changes in cellular processes and pathways not previously associated with melphalan resistance in multiple myeloma cells, including a metabolic switch conforming to the Warburg effect (aerobic glycolysis), and an elevated oxidative stress response mediated by VEGF/IL8-signaling. In addition, up-regulated aldo-keto reductase levels of the AKR1C family involved in prostaglandin synthesis contribute to the resistant phenotype. Finally, selected metabolic and oxidative stress response enzymes were targeted by inhibitors, several of which displayed a selective cytotoxicity against the melphalan-resistant cells and should be further explored to elucidate their potential to overcome melphalan resistance.

  3. Acquired resistance of Listeria monocytogenes in and escaped from liver parenchymal cells to gentamicin is caused by being coated with their plasma membrane.

    PubMed

    Kaneko, Masakazu; Emoto, Yoshiko; Emoto, Masashi

    2014-03-01

    After systemic infection, a majority of Listeria monocytogenes invade liver parenchymal cells (LPC), replicate therein and spread to neighboring cells, suggesting that 3 different types of L. monocytogenes exist in the liver: L. monocytogenes being unable to invade LPC, residing in LPC, and escaped from infected LPC. Although listeriolysin O (LLO) participates in escape of L. monocytogenes from macrophages and L. monocytogenes is susceptible to gentamicin (Gm), it remains elusive whether LLO participates in invasion/escape of L. monocytogenes into/from LPC, and whether L. monocytogenes in/escaped from LPC are susceptible to Gm. In the present study, we examined whether LLO is involved in invasion/escape of L. monocytogenes into/from LPC and whether L. monocytogenes in/escaped from LPC are susceptible to Gm. Invasion/escape of L. monocytogenes were found in LPC lines regardless of LLO expression, and L. monocytogenes in/escaped from LPC lines showed resistance to Gm. L. monocytogenes escaped from LPC lines were coated with their plasma membrane and the acquired resistance to Gm was abrogated by saponin. Our results indicate that invasion/escape of L. monocytogenes into/from LPC occur independently of LLO, and suggest that the acquired resistance of L. monocytogenes in/escaped from LPC to Gm is caused by being coated with their plasma membrane.

  4. Reciprocal positive regulation between Cx26 and PI3K/Akt pathway confers acquired gefitinib resistance in NSCLC cells via GJIC-independent induction of EMT

    PubMed Central

    Yang, J; Qin, G; Luo, M; Chen, J; Zhang, Q; Li, L; Pan, L; Qin, S

    2015-01-01

    Gefitinib efficiency in non-small-cell lung cancer (NSCLC) therapy is limited due to development of drug resistance. The molecular mechanisms of gefitinib resistance remain still unclear. In this study, we first found that connexin 26 (Cx26) is the predominant Cx isoform expressed in various NSCLC cell lines. Then, two gefitinib-resistant (GR) NSCLC cell lines, HCC827 GR and PC9 GR, from their parental cells were established. In these GR cells, the results showed that gefitinib resistance correlated with changes in cellular EMT phenotypes and upregulation of Cx26. Cx26 was detected to be accumulated in the cytoplasm and failed to establish functional gap-junctional intercellular communication (GJIC) either in GR cells or their parental cells. Ectopic expression of GJIC-deficient chimeric Cx26 was sufficient to induce EMT and gefitinib insensitivity in HCC827 and PC9 cells, while knockdown of Cx26 reversed EMT and gefitinib resistance in their GR cells both in vitro and in vivo. Furthermore, Cx26 overexpression could activate PI3K/Akt signaling in these cells. Cx26-mediated EMT and gefitinib resistance were significantly blocked by inhibition of PI3K/Akt pathway. Specifically, inhibition of the constitutive activation of PI3K/Akt pathway substantially suppressed Cx26 expression, and Cx26 was confirmed to functionally interplay with PI3K/Akt signaling to promote EMT and gefitinib resistance in NSCLC cells. In conclusion, the reciprocal positive regulation between Cx26 and PI3K/Akt signaling contributes to acquired gefitinib resistance in NSCLC cells by promoting EMT via a GJIC-independent manner. PMID:26203858

  5. The Systemic Acquired Resistance Regulator OsNPR1 Attenuates Growth by Repressing Auxin Signaling through Promoting IAA-Amido Synthase Expression.

    PubMed

    Li, Xiaozun; Yang, Dong-Lei; Sun, Li; Li, Qun; Mao, Bizeng; He, Zuhua

    2016-09-01

    Systemic acquired resistance is a long-lasting and broad-spectrum disease resistance to pathogens. Our previous study demonstrated that overexpression of NONEXPRESSOR OF PATHOGENESIS-RELATED GENES1 (OsNPR1), a master gene for systemic acquired resistance in rice (Oryza sativa), greatly enhanced resistance to bacterial blight caused by Xanthomonas oryzae pv oryzae However, the growth and development of the OsNPR1 overexpression (OsNPR1-OX) plants were restrained, and the mechanism remained elusive. In this study, we dissected the OsNPR1-induced growth inhibition. We found that the OsNPR1-OX lines displayed phenotypes mimicking auxin-defective mutants, with decreases in root system, seed number and weight, internode elongation, and tiller number. Whole-genome expression analysis revealed that genes related to the auxin metabolism and signaling pathway were differentially expressed between the OsNPR1-OX and wild-type plants. Consistently, the indole-3-acetic acid (IAA) content was decreased and the auxin distribution pattern was altered in OsNPR1-OX plants. Importantly, we found that some GH3 family members, in particular OsGH3.8 coding IAA-amido synthetase, were constitutively up-regulated in OsNPR1-OX plants. Decreased OsGH3.8 expression by RNA interference could partially restore IAA level and largely rescue the restrained growth and development phenotypes but did not affect the disease resistance of OsNPR1-OX plants. Taken together, we revealed that OsNPR1 affects rice growth and development by disrupting the auxin pathway at least partially through indirectly up-regulating OsGH3.8 expression. PMID:27378815

  6. The Systemic Acquired Resistance Regulator OsNPR1 Attenuates Growth by Repressing Auxin Signaling through Promoting IAA-Amido Synthase Expression1[OPEN

    PubMed Central

    2016-01-01

    Systemic acquired resistance is a long-lasting and broad-spectrum disease resistance to pathogens. Our previous study demonstrated that overexpression of NONEXPRESSOR OF PATHOGENESIS-RELATED GENES1 (OsNPR1), a master gene for systemic acquired resistance in rice (Oryza sativa), greatly enhanced resistance to bacterial blight caused by Xanthomonas oryzae pv oryzae. However, the growth and development of the OsNPR1 overexpression (OsNPR1-OX) plants were restrained, and the mechanism remained elusive. In this study, we dissected the OsNPR1-induced growth inhibition. We found that the OsNPR1-OX lines displayed phenotypes mimicking auxin-defective mutants, with decreases in root system, seed number and weight, internode elongation, and tiller number. Whole-genome expression analysis revealed that genes related to the auxin metabolism and signaling pathway were differentially expressed between the OsNPR1-OX and wild-type plants. Consistently, the indole-3-acetic acid (IAA) content was decreased and the auxin distribution pattern was altered in OsNPR1-OX plants. Importantly, we found that some GH3 family members, in particular OsGH3.8 coding IAA-amido synthetase, were constitutively up-regulated in OsNPR1-OX plants. Decreased OsGH3.8 expression by RNA interference could partially restore IAA level and largely rescue the restrained growth and development phenotypes but did not affect the disease resistance of OsNPR1-OX plants. Taken together, we revealed that OsNPR1 affects rice growth and development by disrupting the auxin pathway at least partially through indirectly up-regulating OsGH3.8 expression. PMID:27378815

  7. Spread of community-acquired meticillin-resistant Staphylococcus aureus skin and soft-tissue infection within a family: implications for antibiotic therapy and prevention.

    PubMed

    Amir, N H; Rossney, A S; Veale, J; O'Connor, M; Fitzpatrick, F; Humphreys, H

    2010-04-01

    Outbreaks or clusters of community-acquired meticillin-resistant Staphylococcus aureus (CA-MRSA) within families have been reported. We describe a family cluster of CA-MRSA skin and soft-tissue infection where CA-MRSA was suspected because of recurrent infections which failed to respond to flucloxacillin. While the prevalence of CA-MRSA is low worldwide, CA-MRSA should be considered in certain circumstances depending on clinical presentation and risk assessment. Surveillance cultures of family contacts of patients with MRSA should be considered to help establish the prevalence of CA-MRSA and to inform the optimal choice of empiric antibiotic treatment.

  8. Heterologous Expression and Functional Characterization of the Exogenously Acquired Aminoglycoside Resistance Methyltransferases RmtD, RmtD2, and RmtG

    PubMed Central

    Corrêa, Laís L.; Witek, Marta A.; Zelinskaya, Natalia; Picão, Renata C.

    2015-01-01

    The exogenously acquired 16S rRNA methyltransferases RmtD, RmtD2, and RmtG were cloned and heterologously expressed in Escherichia coli, and the recombinant proteins were purified to near homogeneity. Each methyltransferase conferred an aminoglycoside resistance profile consistent with m7G1405 modification, and this activity was confirmed by in vitro 30S methylation assays. Analyses of protein structure and interaction with S-adenosyl-l-methionine suggest that the molecular mechanisms of substrate recognition and catalysis are conserved across the 16S rRNA (m7G1405) methyltransferase family. PMID:26552988

  9. The concentration of erlotinib in the cerebrospinal fluid of patients with brain metastasis from non-small-cell lung cancer

    PubMed Central

    DENG, YANMING; FENG, WEINENG; WU, JING; CHEN, ZECHENG; TANG, YICONG; ZHANG, HUA; LIANG, JIANMIAO; XIAN, HAIBING; ZHANG, SHUNDA

    2014-01-01

    It has been demonstrated that erlotinib is effective in treating patients with brain metastasis from non-small-cell lung cancer. However, the number of studies determining the erlotinib concentration in these patients is limited. The purpose of this study was to measure the concentration of erlotinib in the cerebrospinal fluid of patients with brain metastasis from non-small-cell lung carcinoma. Six patients were treated with the standard recommended daily dose of erlotinib (150 mg) for 4 weeks. All the patients had previously received chemotherapy, but no brain radiotherapy. At the end of the treatment period, blood plasma and cerebrospinal fluid samples were collected and the erlotinib concentration was determined by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The average erlotinib concentration in the blood plasma and the cerebrospinal fluid was 717.7±459.7 and 23.7±13.4 ng/ml, respectively. The blood-brain barrier permeation rate of erlotinib was found to be 4.4±3.2%. In patients with partial response (PR), stable disease (SD) and progressive disease (PD), the average concentrations of erlotinib in the cerebrospinal fluid were 35.5±19.0, 19.1±8.7 and 16.4±5.9 ng/ml, respectively. In addition, the efficacy rate of erlotinib for metastatic brain lesions was 33.3%, increasing to 50% in patients with EGFR mutations. However, erlotinib appeared to be ineffective in cases with wild-type EGFR. In conclusion, a relatively high concentration of erlotinib was detected in the cerebrospinal fluid of patients with brain metastases from non-small-cell lung cancer. Thus, erlotinib may be considered as a treatment option for this patient population. PMID:24649318

  10. Low expression of Abelson interactor-1 is linked to acquired drug resistance in Bcr-Abl-induced leukemia.

    PubMed

    Chorzalska, A; Salloum, I; Shafqat, H; Khan, S; Marjon, P; Treaba, D; Schorl, C; Morgan, J; Bryke, C R; Falanga, V; Zhao, T C; Reagan, J; Winer, E; Olszewski, A J; Al-Homsi, A S; Kouttab, N; Dubielecka, P M

    2014-11-01

    The basis for persistence of leukemic stem cells in the bone marrow microenvironment remains poorly understood. We present evidence that signaling cross-talk between α4 integrin and Abelson interactor-1 (Abi-1) is involved in the acquisition of an anchorage-dependent phenotype and drug resistance in Bcr-Abl-positive leukemia cells. Comparison of Abi-1 (ABI-1) and α4 integrin (ITGA4) gene expression in relapsing Bcr-Abl-positive CD34+progenitor cells demonstrated a reduction in Abi-1 and an increase in α4 integrin mRNA in the absence of Bcr-Abl mutations. This inverse correlation between Abi-1 and α4 integrin expression, as well as linkage to elevated phospho-Akt and phospho-Erk signaling, was confirmed in imatinib mesylate -resistant leukemic cells. These results indicate that the α4-Abi-1 signaling pathway may mediate acquisition of the drug-resistant phenotype of leukemic cells.

  11. Elevated hepatocyte growth factor expression as an autocrine c-Met activation mechanism in acquired resistance to sorafenib in hepatocellular carcinoma cells.

    PubMed

    Firtina Karagonlar, Zeynep; Koc, Dogukan; Iscan, Evin; Erdal, Esra; Atabey, Neşe

    2016-04-01

    Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer and the third leading cause of cancer-related deaths worldwide. Limitations in HCC treatment result due to poor prognosis and resistance against traditional radiotherapy and chemotherapies. The multikinase inhibitor sorafenib is the only FDA approved drug available for advanced HCC patients, and development of second-line treatment options for patients who cannot tolerate or develop resistance to sorafenib is an urgent medical need. In this study, we established sorafenib-resistant cells from Huh7 and Mahlavu cell lines by long-term sorafenib exposure. Sorafenib-resistant HCC cells acquired spindle-shape morphology, upregulated mesenchymal markers, and showed significant increase in both migration and invasion abilities compared to their parental counterparts. Moreover, after long-term sorafenib treatment, HCC cells showed induction of hepatocyte growth factor (HGF) synthesis and secretion along with increased levels of c-Met kinase and its active phosphorylated form, indicating autocrine activation of HGF/c-Met signaling. Importantly, the combined treatment of the resistant cells with c-Met kinase inhibitor SU11274 and HGF neutralizing antibody significantly reversed the increased invasion ability of the cells. The combined treatment also significantly augmented sorafenib-induced apoptosis, suggesting restoration of sorafenib sensitivity. These results describe, for the first time, compensatory upregulation of HGF synthesis leading to autocrine activation of HGF/c-Met signaling as a novel cellular strategy in the acquisition of sorafenib resistance. Therefore, we suggest that combinatorial therapeutic strategies with HGF and c-Met inhibitors comprise promising candidates for overcoming sorafenib resistance. PMID:26790028

  12. Disruption of an Enterococcus faecium Species-Specific Gene, a Homologue of Acquired Macrolide Resistance Genes of Staphylococci, Is Associated with an Increase in Macrolide Susceptibility

    PubMed Central

    Singh, Kavindra V.; Malathum, Kumthorn; Murray, Barbara E.

    2001-01-01

    The complete sequence (1,479 nucleotides) of msrC, part of which was recently reported by others using a different strain, was determined. This gene was found in 233 of 233 isolates of Enterococcus faecium but in none of 265 other enterococci. Disruption of msrC was associated with a two- to eightfold decrease in MICs of erythromycin azithromycin, tylosin, and quinupristin, suggesting that it may explain in part the apparent greater intrinsic resistance to macrolides of isolates of E. faecium relative to many streptococci. This endogenous, species-specific gene of E. faecium is 53% identical to msr(A), suggesting that it may be a remote progenitor of the acquired macrolide resistance gene found in some isolates of staphylococci. PMID:11120975

  13. Emergence of resistance to fluconazole as a cause of failure during treatment of histoplasmosis in patients with acquired immunodeficiency disease syndrome.

    PubMed

    Wheat, L J; Connolly, P; Smedema, M; Brizendine, E; Hafner, R

    2001-12-01

    In sequential clinical trials of treatment for histoplasmosis in patients with acquired immunodeficiency syndrome, therapy with fluconazole failed in a higher proportion of patients than did therapy with itraconazole. To determine the cause for failure with fluconazole, antifungal susceptibility testing that used modified National Committee on Clinical Laboratory Standards procedures was performed on all baseline and failure isolates. Failure occurred more frequently in patients with baseline isolates with fluconazole minimum inhibitory concentrations (MICs) > or =5 microg/mL versus lower MICs; 29% versus 3%, respectively. There was at least a 4-fold increase in fluconazole MIC in the isolates from 10 (59%) of 17 patients for whom paired pretreatment and failure or relapse isolates were available. Cross-resistance to itraconazole was not seen. In conclusion, fluconazole is less active than itraconazole for Histoplasma capsulatum and induces resistance during therapy, which accounted for treatment failure in some patients.

  14. Acquired resistance to epidermal growth factor receptor tyrosine kinase inhibitors in EGFR-mutant non-small cell lung cancer: a new era begins.

    PubMed

    Remon, J; Morán, T; Majem, M; Reguart, N; Dalmau, E; Márquez-Medina, D; Lianes, P

    2014-02-01

    The discovery of mutated oncogenes has opened up a new era for the development of more effective treatments for non-small cell lung cancer patients (NSCLC) harbouring EGFR mutations. However, patients with EGFR-activating mutation ultimately develop acquired resistance (AR). Several studies have identified some of the mechanisms involved in the development of AR to EGFR tyrosine kinase inhibitors (TKI) that can be potential therapeutic strategies, although in up to 30% of cases, the underlying mechanism of AR are still unexplained. In this review we aim to summarize the main mechanisms of AR to EGFR TKI and some clinical strategies that can be used in the daily clinical practice to overcome this resistance and try to prolong the outcomes in this subgroup of patients.

  15. Gastrointestinal perforations in patients treated with erlotinib: A report of two cases with fatal outcome and literature review.

    PubMed

    Gass-Jégu, Florence; Gschwend, Anthony; Gairard-Dory, Anne-Cécile; Mennecier, Bertrand; Tebacher-Alt, Martine; Gourieux, Bénédicte; Quoix, Élisabeth

    2016-09-01

    Erlotinib has been approved as second-line treatment in patients with non-small cell lung cancer (NSCLC) experiencing relapse after first-line platinum-based chemotherapy. Herein, we report two occurrences of erlotinib-associated gastrointestinal perforation (GIP) in NSCLC patients. Two patients aged 60 and 79 years received erlotinib as third- and second-line NSCLC treatment, respectively. GIP occurred following 3 weeks and 6 months of erlotinib treatment, leading to death a few days later in both patients, neither of whom had any intestinal metastasis. Risk factors related to erlotinib-induced GIP were concomitant oral corticosteroid therapy and ciprofloxacin administration, which may result in erlotinib overexposure. GIP is a severe adverse drug reaction of erlotinib, infrequently described in the literature, compared to other targeted therapies. The lethal risk of erlotinib-associated GIP should be taken into account when evaluating the benefit-risk balance of erlotinib in patients without epidermal growth factor receptor activating mutations. PMID:27565918

  16. Rapid Detection of Acquired and Inducible Clarithromycin Resistance in Mycobacterium abscessus Group by a Simple Real-Time PCR Assay.

    PubMed

    Luo, Robert F; Curry, Cheyenne; Taylor, Nathan; Budvytiene, Indre; Banaei, Niaz

    2015-07-01

    By targeting the erm(41) and rrl genes in the Mycobacterium abscessus group, a multiplex real-time PCR assay for clarithromycin resistance showed 95% (38/40) concordance with nucleic acid testing and 95% (37/39) concordance with phenotypic testing. This assay provides a simple and rapid alternative to extended incubation or erm(41) sequencing. PMID:25903572

  17. Focal Adhesion Kinase Inhibitors in Combination with Erlotinib Demonstrate Enhanced Anti-Tumor Activity in Non-Small Cell Lung Cancer

    PubMed Central

    Howe, Grant A.; Xiao, Bin; Zhao, Huijun; Al-Zahrani, Khalid N.; Hasim, Mohamed S.; Villeneuve, James; Sekhon, Harmanjatinder S.; Goss, Glenwood D.; Sabourin, Luc A.; Dimitroulakos, Jim; Addison, Christina L.

    2016-01-01

    Blockade of epidermal growth factor receptor (EGFR) activity has been a primary therapeutic target for non-small cell lung cancers (NSCLC). As patients with wild-type EGFR have demonstrated only modest benefit from EGFR tyrosine kinase inhibitors (TKIs), there is a need for additional therapeutic approaches in patients with wild-type EGFR. As a key component of downstream integrin signalling and known receptor cross-talk with EGFR, we hypothesized that targeting focal adhesion kinase (FAK) activity, which has also been shown to correlate with aggressive stage in NSCLC, would lead to enhanced activity of EGFR TKIs. As such, EGFR TKI-resistant NSCLC cells (A549, H1299, H1975) were treated with the EGFR TKI erlotinib and FAK inhibitors (PF-573,228 or PF-562,271) both as single agents and in combination. We determined cell viability, apoptosis and 3-dimensional growth in vitro and assessed tumor growth in vivo. Treatment of EGFR TKI-resistant NSCLC cells with FAK inhibitor alone effectively inhibited cell viability in all cell lines tested; however, its use in combination with the EGFR TKI erlotinib was more effective at reducing cell viability than either treatment alone when tested in both 2- and 3-dimensional assays in vitro, with enhanced benefit seen in A549 cells. This increased efficacy may be due in part to the observed inhibition of Akt phosphorylation when the drugs were used in combination, where again A549 cells demonstrated the most inhibition following treatment with the drug combination. Combining erlotinib with FAK inhibitor was also potent in vivo as evidenced by reduced tumor growth in the A549 mouse xenograft model. We further ascertained that the enhanced sensitivity was irrespective of the LKB1 mutational status. In summary, we demonstrate the effectiveness of combining erlotinib and FAK inhibitors for use in known EGFR wild-type, EGFR TKI resistant cells, with the potential that a subset of cell types, which includes A549, could be particularly

  18. Familial clustering of Taenia solium cysticercosis in the rural pigs of Mexico: hints of genetic determinants in innate and acquired resistance to infection.

    PubMed

    Sciutto, E; Martínez, J J; Huerta, M; Avila, R; Fragoso, G; Villalobos, N; de Aluja, A; Larralde, C

    2003-10-20

    In two rural villages of the state of Puebla, Mexico, where Taenia solium pig cysticercosis is highly endemic, 120 pairs of young out-bred piglets were used to assay what proved to be an effective synthetic peptide vaccine against naturally acquired cysticercosis. Because the piglets used were all sired by one of three distinct studs in many different out-bred sows, the prevalence and intensity of infection, as well as degree of protection conferred by the vaccine, could be related to each of the three stud families (A-C). The highest prevalence was found in the C family (25%), whilst the prevalence of B and A families were 21.6 and 4.4%, respectively. Familial clustering of cases was even more conspicuous in vaccinated pigs than in not-vaccinated ones: seven of the nine cysticercosis cases that occurred in the vaccinated group belonged to the C family (7/26) and two to the B family (2/23), whilst the vaccine rendered the A family totally resistant (0/71). Parasite numbers were also higher in the C family in both nai;ve and vaccinated pigs. Familial clustering of cases and of large parasite numbers in naive and vaccinated pigs hint to the relevance of their genetic background in their innate and acquired resistance to cysticercosis.

  19. What hides behind the MASC: clinical response and acquired resistance to entrectinib after ETV6-NTRK3 identification in a mammary analogue secretory carcinoma (MASC)

    PubMed Central

    Drilon, A.; Li, G.; Dogan, S.; Gounder, M.; Shen, R.; Arcila, M.; Wang, L.; Hyman, D. M.; Hechtman, J.; Wei, G.; Cam, N. R.; Christiansen, J.; Luo, D.; Maneval, E. C.; Bauer, T.; Patel, M.; Liu, S. V.; Ou, S. H. I.; Farago, A.; Shaw, A.; Shoemaker, R. F.; Lim, J.; Hornby, Z.; Multani, P.; Ladanyi, M.; Berger, M.; Katabi, N.; Ghossein, R.; Ho, A. L.

    2016-01-01

    Background Mammary analogue secretory carcinoma (MASC) is a recently described pathologic entity. We report the case of a patient with an initial diagnosis of salivary acinic cell carcinoma later reclassified as MASC after next-generation sequencing revealed an ETV6-NTRK3 fusion. Patients and methods This alteration was targeted with the pan-Trk inhibitor entrectinib (Ignyta), which possesses potent in vitro activity against cell lines containing various NTRK1/2/3 fusions. Results A dramatic and durable response was achieved with entrectinib in this patient, followed by acquired resistance that correlated with the appearance of a novel NTRK3 G623R mutation. Structural modeling predicts that this alteration sterically interferes with drug binding, correlating to decreased sensitivity to drug inhibition observed in cell-based assays. Conclusions This first report of clinical activity with TrkC inhibition and the development of acquired resistance in an NTRK3-rearranged cancer emphasize the utility of comprehensive molecular profiling and targeted therapy for rare malignancies (NCT02097810). PMID:26884591

  20. A platinum-based hybrid drug design approach to circumvent acquired resistance to molecular targeted tyrosine kinase inhibitors

    NASA Astrophysics Data System (ADS)

    Wei, Yuming; Poon, Daniel C.; Fei, Rong; Lam, Amy S. M.; Au-Yeung, Steve C. F.; To, Kenneth K. W.

    2016-05-01

    Three molecular targeted tyrosine kinase inhibitors (TKI) were conjugated to classical platinum-based drugs with an aim to circumvent TKI resistance, predominately mediated by the emergence of secondary mutations on oncogenic kinases. The hybrids were found to maintain specificity towards the same oncogenic kinases as the original TKI. Importantly, they are remarkably less affected by TKI resistance, presumably due to their unique structure and the observed dual mechanism of anticancer activity (kinase inhibition and DNA damage). The study is also the first to report the application of a hybrid drug approach to switch TKIs from being efflux transporter substrates into non-substrates. TKIs cannot penetrate into the brain for treating metastases because of efflux transporters at the blood brain barrier. The hybrids were found to escape drug efflux and they accumulate more than the original TKI in the brain in BALB/c mice. Further development of the hybrid compounds is warranted.

  1. A platinum-based hybrid drug design approach to circumvent acquired resistance to molecular targeted tyrosine kinase inhibitors.

    PubMed

    Wei, Yuming; Poon, Daniel C; Fei, Rong; Lam, Amy S M; Au-Yeung, Steve C F; To, Kenneth K W

    2016-05-06

    Three molecular targeted tyrosine kinase inhibitors (TKI) were conjugated to classical platinum-based drugs with an aim to circumvent TKI resistance, predominately mediated by the emergence of secondary mutations on oncogenic kinases. The hybrids were found to maintain specificity towards the same oncogenic kinases as the original TKI. Importantly, they are remarkably less affected by TKI resistance, presumably due to their unique structure and the observed dual mechanism of anticancer activity (kinase inhibition and DNA damage). The study is also the first to report the application of a hybrid drug approach to switch TKIs from being efflux transporter substrates into non-substrates. TKIs cannot penetrate into the brain for treating metastases because of efflux transporters at the blood brain barrier. The hybrids were found to escape drug efflux and they accumulate more than the original TKI in the brain in BALB/c mice. Further development of the hybrid compounds is warranted.

  2. A platinum-based hybrid drug design approach to circumvent acquired resistance to molecular targeted tyrosine kinase inhibitors

    PubMed Central

    Wei, Yuming; Poon, Daniel C.; Fei, Rong; Lam, Amy S. M.; Au-Yeung, Steve C. F.; To, Kenneth K. W.

    2016-01-01

    Three molecular targeted tyrosine kinase inhibitors (TKI) were conjugated to classical platinum-based drugs with an aim to circumvent TKI resistance, predominately mediated by the emergence of secondary mutations on oncogenic kinases. The hybrids were found to maintain specificity towards the same oncogenic kinases as the original TKI. Importantly, they are remarkably less affected by TKI resistance, presumably due to their unique structure and the observed dual mechanism of anticancer activity (kinase inhibition and DNA damage). The study is also the first to report the application of a hybrid drug approach to switch TKIs from being efflux transporter substrates into non-substrates. TKIs cannot penetrate into the brain for treating metastases because of efflux transporters at the blood brain barrier. The hybrids were found to escape drug efflux and they accumulate more than the original TKI in the brain in BALB/c mice. Further development of the hybrid compounds is warranted. PMID:27150583

  3. Localization of DIR1 at the tissue, cellular and subcellular levels during Systemic Acquired Resistance in Arabidopsis using DIR1:GUS and DIR1:EGFP reporters

    PubMed Central

    2011-01-01

    Background Systemic Acquired Resistance (SAR) is an induced resistance response to pathogens, characterized by the translocation of a long-distance signal from induced leaves to distant tissues to prime them for increased resistance to future infection. DEFECTIVE in INDUCED RESISTANCE 1 (DIR1) has been hypothesized to chaperone a small signaling molecule to distant tissues during SAR in Arabidopsis. Results DIR1 promoter:DIR1-GUS/dir1-1 lines were constructed to examine DIR1 expression. DIR1 is expressed in seedlings, flowers and ubiquitously in untreated or mock-inoculated mature leaf cells, including phloem sieve elements and companion cells. Inoculation of leaves with SAR-inducing avirulent or virulent Pseudomonas syringae pv tomato (Pst) resulted in Type III Secretion System-dependent suppression of DIR1 expression in leaf cells. Transient expression of fluorescent fusion proteins in tobacco and intercellular washing fluid experiments indicated that DIR1's ER signal sequence targets it for secretion to the cell wall. However, DIR1 expressed without a signal sequence rescued the dir1-1 SAR defect, suggesting that a cytosolic pool of DIR1 is important for the SAR response. Conclusions Although expression of DIR1 decreases during SAR induction, the protein localizes to all living cell types of the vasculature, including companion cells and sieve elements, and therefore DIR1 is well situated to participate in long-distance signaling during SAR. PMID:21896186

  4. Prostate cancer bone metastases acquire resistance to androgen deprivation via WNT5A-mediated BMP-6 induction

    PubMed Central

    Lee, G T; Kang, D I; Ha, Y-S; Jung, Y S; Chung, J; Min, K; Kim, T H; Moon, K H; Chung, J M; Lee, D H; Kim, W-J; Kim, I Y

    2014-01-01

    Background: Androgen ablation is the first-line therapy for patients with metastatic prostate cancer (CaP). However, castration resistance will eventually emerge. In the present study, we have investigated the role of bone morphogenetic protein-6 (BMP-6) in the development of castration-resistant prostate cancer (CRPC) in the context of bone metastases. Methods: We initially investigated the clinical course of 158 men with advanced CaP who were treated with primary androgen deprivation therapy. To elucidate the underlying mechanism of CRPC in the context of bone metastases, we examined the impact of bone stromal cells on CaP in the absence of androgens using a co-culture model. Results: In the 158 patients, we found that the median time to prostate-specific antigen progression was significantly shorter when bone metastases were present (14 months (95% CI, 10.2–17.8 months) vs 57 months (95% CI, 19.4–94.6 months)). These results suggest that bone–tumour interactions may accelerate castration resistance. Consistent with this hypothesis, in vitro co-cultures demonstrated that CaP cells proliferated under an androgen-depleted condition when incubated with bone stromal cells. Mechanistically, gene expression analysis using quantitative polymerase chain reaction arrays showed a dramatic induction of BMP-6 by CaP cell lines in the presence of bone stromal cells. Further studies revealed that WNT5A derived from bone stromal cells induced the expression of BMP-6 by CaP cells; BMP-6 in turn stimulated cellular proliferation of CaP cells in an androgen-deprived media via a physical interaction between Smad5 and β-catenin. Intracellularly, WNT5A increased BMP-6 expression via protein kinase C/NF-κB pathway in CaP cell lines. Conclusions: These observations suggest that bone–CaP interaction leads to castration resistance via WNT5A/BMP-6 loop. PMID:24518599

  5. Elevated Cellular PD1/PD-L1 Expression Confers Acquired Resistance to Cisplatin in Small Cell Lung Cancer Cells.

    PubMed

    Yan, Fei; Pang, Jiuxia; Peng, Yong; Molina, Julian R; Yang, Ping; Liu, Shujun

    2016-01-01

    Although small cell lung cancer (SCLC) is highly responsive to chemotherapies (e.g., cisplatin-etoposide doublet), virtually almost all responsive SCLC patients experience disease recurrence characterized by drug resistance. The mechanisms underlying cisplatin resistance remain elusive. Here we report that cell-intrinsic expression of PD1 and PD-L1, two immune checkpoints, is required for sustained expansion of SCLC cells under cisplatin selection. Indeed, PD1 and PD-L1 were expressed at a higher level in lung cancer cell lines, tumor tissues, and importantly, in SCLC cells resistant to cisplatin (H69R, H82R), when compared to respective controls. Genetic abrogation of PD1 and PD-L1 in H69R and H82R cells decreased their proliferation rate, and restored their sensitivity to cisplatin. Mechanistically, PD-L1 upregulation in H69R and H82R cells was attributed to the overexpression of DNA methyltransferase 1 (DNMT1) or receptor tyrosine kinase KIT, as knockdown of DNMT1 or KIT in H69R and H82R cells led to PD-L1 downregulation. Consequently, combined knockdown of PD-L1 with KIT or DNMT1 resulted in more pronounced inhibition of H69R and H82R cell growth. Thus, cell intrinsic PD1/PD-L1 signaling may be a predictor for poor efficacy of cisplatin treatment, and targeting the cellular PD1/PD-L1 axis may improve chemosensitization of aggressive SCLC.

  6. Neisseria gonorrhoeae acquire a new principal outer-membrane protein when transformed to resistance to serum bactericidal activity.

    PubMed Central

    Hildebrandt, J F; Mayer, L W; Wang, S P; Buchanan, T M

    1978-01-01

    Resistance to the complement-dependent bactericidal activity of normal human serum is found in nearly all Neisseria gonorrhoeae strains causing disseminated gonococcal infection. Transformation of serum-sensitive gonococcal strain NRL 7189 to serum resistance using deoxyribonucleic acid from three separate disseminated-infection gonococci was accompanied by simultaneous structural and antigenic changes in the principal outer-membrane protein (POMP) of the transformants. In each of 10 separate transformations, there was a reduction in subunit molecular weight of the POMP from that in the recipient (39,000) to that in the deoxyribonucleic acid donors (36,500). Also, in each instance the POMP antigenic type, as measured by enzyme-linked immunosorbent assay, converted from that of the recipient to an antigenic type common to each DGI donor strain. This conversion of POMP antigen was reflected in part by changes in the surface fluorescence of the transformed gonococci to the microimmunofluorescence pattern of the donor strains. These results suggested that serum resistance of gonococci is related to the possession of a POMP of characteristic subunit molecular weight and antigenicity. Images PMID:78895

  7. Fisetin, a dietary bioflavonoid, reverses acquired Cisplatin-resistance of lung adenocarcinoma cells through MAPK/Survivin/Caspase pathway

    PubMed Central

    Zhuo, Wenlei; Zhang, Liang; Zhu, Yi; Zhu, Bo; Chen, Zhengtang

    2015-01-01

    Cisplatin has been a key chemotherapy drug for treatment of non-small cell lung cancer (NSCLC) for decades. However, the efficacy of Cisplatin is usually reduced by the occurrence of drug-resistance of cancer cells. Fisetin is a flavonol naturally found in many fruits and vegetables, which has been reported to suppress cell proliferation and induce apoptosis in various cancers. In this study, we aimed to investigate whether Fisetin was capable of enhancing cytotoxicity of Cisplatin in Cisplatin-resistant NSCLC cells, and explore the possible signaling pathways involved. Cisplatin-resistant NSCLC cells, A549-CR, was established by repeated subculturing of A549 cells with increasing Cisplatin. Proliferation ability was assessed by MTT analysis and apoptosis was detected by flow cytometry. The results showed that Fisetin effectively increased sensitivity of A549-CR cells to Cisplatin, possibly mediated by inhibiting aberrant activation of MAPK signaling pathways. This increases the possibility of Fisetin as a promising agent for lung cancer therapy. PMID:26692948

  8. The Effect of Infection Control Nurses on the Occurrence of Pseudomonas aeruginosa Healthcare-Acquired Infection and Multidrug-Resistant Strains in Critically-Ill Children

    PubMed Central

    Xu, Wei; He, Linxi; Liu, Chunfeng; Rong, Jian; Shi, Yongyan; Song, Wenliang; Zhang, Tao; Wang, Lijie

    2015-01-01

    Background Healthcare-acquired Pseudomonas aeruginosa (P. aeruginosa) infections in the Pediatric Intensive Care Unit (PICU), which have a high incidence, increase treatment costs and mortality, and seriously threaten the safety of critically ill children. It is essential to seek convenient and effective methods to control and prevent healthcare-acquired infections (HAIs). This research was conducted to study the effect of infection control nurses on the occurrence of P. aeruginosa HAIs and multi-drug resistance (MDR) strains in PICU. Methods The clinical data was divided into two groups, with the age ranging from 1 month to 14 years. One group of the critically ill patients(N = 3,722) was admitted to PICU from 2007 to 2010, without the management of infection control nurses. The other group of the critically ill patients (N = 3,943) was admitted to PICU from 2011 to 2013, with the management of infection control nurses. Compare the mortality, morbidity and the incidence of acquired P. aeruginosa infections to evaluate the effect of infection control nurses. Results After implementation of the post of infection control nurses, the patient's overall mortality fell from 4.81% to 3.73%. Among the patients with endotracheal intubation more than 48 hours, the incidence of endotracheal intubation-related pneumonia decreased from 44.6% to 34.32%. The mortality of patients with endotracheal intubation decreased from 16.96% to 10.17%, and the morbidity of HAIs with P. aeruginosa decreased from 1.89% to 1.07%. The mutual different rate (MDR) dropped from 67.95% to 44.23%. There were remarkable differences in these rates between the two groups (p<0.05). Conclusion Implementing the post of infection control nurses is associated with effectively reducing the HAI rate, especially the incidence and morbidity of P. aeruginosa HAIs, reducing PICU mortality, improving P. aeruginosa drug resistance. PMID:26630032

  9. Contrasting Roles of the Apoplastic Aspartyl Protease APOPLASTIC, ENHANCED DISEASE SUSCEPTIBILITY1-DEPENDENT1 and LEGUME LECTIN-LIKE PROTEIN1 in Arabidopsis Systemic Acquired Resistance.

    PubMed

    Breitenbach, Heiko H; Wenig, Marion; Wittek, Finni; Jordá, Lucia; Maldonado-Alconada, Ana M; Sarioglu, Hakan; Colby, Thomas; Knappe, Claudia; Bichlmeier, Marlies; Pabst, Elisabeth; Mackey, David; Parker, Jane E; Vlot, A Corina

    2014-04-22

    Systemic acquired resistance (SAR) is an inducible immune response that depends on ENHANCED DISEASE SUSCEPTIBILITY1 (EDS1). Here, we show that Arabidopsis (Arabidopsis thaliana) EDS1 is required for both SAR signal generation in primary infected leaves and SAR signal perception in systemic uninfected tissues. In contrast to SAR signal generation, local resistance remains intact in eds1 mutant plants in response to Pseudomonas syringae delivering the effector protein AvrRpm1. We utilized the SAR-specific phenotype of the eds1 mutant to identify new SAR regulatory proteins in plants conditionally expressing AvrRpm1. Comparative proteomic analysis of apoplast-enriched extracts from AvrRpm1-expressing wild-type and eds1 mutant plants led to the identification of 12 APOPLASTIC, EDS1-DEPENDENT (AED) proteins. The genes encoding AED1, a predicted aspartyl protease, and another AED, LEGUME LECTIN-LIKE PROTEIN1 (LLP1), were induced locally and systemically during SAR signaling and locally by salicylic acid (SA) or its functional analog, benzo 1,2,3-thiadiazole-7-carbothioic acid S-methyl ester. Because conditional overaccumulation of AED1-hemagglutinin inhibited SA-induced resistance and SAR but not local resistance, the data suggest that AED1 is part of a homeostatic feedback mechanism regulating systemic immunity. In llp1 mutant plants, SAR was compromised, whereas the local resistance that is normally associated with EDS1 and SA as well as responses to exogenous SA appeared largely unaffected. Together, these data indicate that LLP1 promotes systemic rather than local immunity, possibly in parallel with SA. Our analysis reveals new positive and negative components of SAR and reinforces the notion that SAR represents a distinct phase of plant immunity beyond local resistance.

  10. Rapid detection of the epidermal growth factor receptor mutation in non-small-cell lung cancer for analysis of acquired resistance using molecular beacons.

    PubMed

    Oh, Young-Hee; Kim, Youngwook; Kim, Young-Pil; Seo, Soo-Won; Mitsudomi, Tetsuya; Ahn, Myung-Ju; Park, Keunchil; Kim, Hak-Sung

    2010-09-01

    A secondary mutation (T790M) in epidermal growth factor receptor (EGFR) is a hallmark of acquired resistance to EGFR inhibitors used to treat non-small-cell lung cancer (NSCLC). Therefore, identifying the T790M mutation is crucial to guide treatment decisions. Given that DNA sequencing methods are time-consuming and insensitive, we developed and investigated the feasibility of using molecular beacons for the detection of the T790M mutation in EGFR. A molecular beacon complementary to the region of the secondary EGFR mutation (T790M) was designed and used in NSCLC samples bearing drug-sensitive and -resistant EGFR mutations. For a rapid and simple assay, we attempted to use the molecular beacon with real-time PCR and in situ fluorescence imaging. The ability of the designed molecular beacon to specifically detect the T790M mutation of EGFR was tested for samples from two patients with drug resistance and compared with conventional DNA sequencing methods. The molecular beacon successfully detected the T790M mutation in patient samples with drug resistance. The sensitivity of the molecular beacon, which detected as little as 2% of genomic DNA from the drug-resistant cells (H1975), was much higher than direct sequencing. Furthermore, in situ fluorescence imaging with the molecular beacon gave rise to a distinguishable signal for the T790M mutation in drug-resistant cells. The molecular beacon-based approach enabled rapid and sensitive detection of the EGFR mutation (T790M) in NSCLC with in situ fluorescence imaging, which can be directed to determine various treatment options in patients with cancer.

  11. Intrinsic resistance to EGFR tyrosine kinase inhibitors in advanced non-small-cell lung cancer with activating EGFR mutations

    PubMed Central

    Wang, Jun; Wang, Baocheng; Chu, Huili; Yao, Yunfeng

    2016-01-01

    Identifying activating EGFR mutations is a useful predictive strategy that helps select a population of advanced non-small-cell lung cancer (NSCLC) patients for treatment with EGFR tyrosine kinase inhibitors (TKIs). Patients with sensitizing EGFR mutations (predominantly an in-frame deletion in exon 19 and an L858R substitution) are highly responsive to first-generation EGFR TKIs, such as gefitinib and erlotinib, and show improved progression-free survival without serious side effects. However, all patients with activating EGFR mutations who are initially responsive to EGFR TKIs eventually develop acquired resistance after a median progression-free survival of 10–16 months, followed by disease progression. Moreover, ~20%–30% of NSCLC patients have no objective tumor regression on initial EGFR TKI treatment, although they harbor an activating EGFR mutation. These patients represent an NSCLC subgroup that is defined as having intrinsic or primary resistance to EGFR TKIs. Different mechanisms of acquired EGFR TKI resistance have been identified, and several novel compounds have been developed to reverse acquired resistance, but little is known about EGFR TKI intrinsic resistance. In this review, we summarize the latest findings involving mechanisms of intrinsic resistance to EGFR TKIs in advanced NSCLC with activating EGFR mutations and present possible therapeutic strategies to overcome this resistance. PMID:27382309

  12. Elevated Cellular PD1/PD-L1 Expression Confers Acquired Resistance to Cisplatin in Small Cell Lung Cancer Cells

    PubMed Central

    Yan, Fei; Pang, Jiuxia; Peng, Yong; Molina, Julian R.; Yang, Ping; Liu, Shujun

    2016-01-01

    Although small cell lung cancer (SCLC) is highly responsive to chemotherapies (e.g., cisplatin-etoposide doublet), virtually almost all responsive SCLC patients experience disease recurrence characterized by drug resistance. The mechanisms underlying cisplatin resistance remain elusive. Here we report that cell-intrinsic expression of PD1 and PD-L1, two immune checkpoints, is required for sustained expansion of SCLC cells under cisplatin selection. Indeed, PD1 and PD-L1 were expressed at a higher level in lung cancer cell lines, tumor tissues, and importantly, in SCLC cells resistant to cisplatin (H69R, H82R), when compared to respective controls. Genetic abrogation of PD1 and PD-L1 in H69R and H82R cells decreased their proliferation rate, and restored their sensitivity to cisplatin. Mechanistically, PD-L1 upregulation in H69R and H82R cells was attributed to the overexpression of DNA methyltransferase 1 (DNMT1) or receptor tyrosine kinase KIT, as knockdown of DNMT1 or KIT in H69R and H82R cells led to PD-L1 downregulation. Consequently, combined knockdown of PD-L1 with KIT or DNMT1 resulted in more pronounced inhibition of H69R and H82R cell growth. Thus, cell intrinsic PD1/PD-L1 signaling may be a predictor for poor efficacy of cisplatin treatment, and targeting the cellular PD1/PD-L1 axis may improve chemosensitization of aggressive SCLC. PMID:27610620

  13. Trends towards lower antimicrobial susceptibility and characterization of acquired resistance among clinical isolates of Brachyspira hyodysenteriae in Spain.

    PubMed

    Hidalgo, Álvaro; Carvajal, Ana; Vester, Birte; Pringle, Märit; Naharro, Germán; Rubio, Pedro

    2011-07-01

    The antimicrobial susceptibility of clinical isolates of Brachyspira hyodysenteriae in Spain was monitored, and the underlying molecular mechanisms of resistance were investigated. MICs of tylosin, tiamulin, valnemulin, lincomycin, and tylvalosin were determined for 87 B. hyodysenteriae isolates recovered from 2008 to 2009 by broth dilution. Domain V of the 23S rRNA gene and the ribosomal protein L3 gene were sequenced in 20 isolates for which the tiamulin MIC was ≥ 4 μg/ml, presenting decreased susceptibility, and in 18 tiamulin-susceptible isolates (MIC ≤ 0.125 μg/ml), and all isolates were typed by multiple-locus variable-number tandem repeats analysis. A comparison with antimicrobial susceptibility data from 2000 to 2007 showed an increase in pleuromutilin resistance over time, doubling the number of isolates with decreased susceptibility to tiamulin. No alteration in susceptibility was detected for lincomycin, and the MIC of tylosin remained high (MIC(50) > 128 μg/ml). The decreased susceptibility to tylosin and lincomycin can be explained by mutations at position A2058 of the 23S rRNA gene (Escherichia coli numbering). A2058T was the predominant mutation, but A2058G also was found together with a change of the neighboring base pair at positions 2057 to 2611. The role of additional point mutations in the vicinity of the peptidyl transferase center and mutations in the L3 at amino acids 148 and 149 and their possible involvement in antimicrobial susceptibility are considered. An association between G2032A and high levels of tiamulin and lincomycin MICs was found, suggesting an increasing importance of this mutation in antimicrobial resistance of clinical isolates of B. hyodysenteriae. PMID:21555771

  14. Elevated Cellular PD1/PD-L1 Expression Confers Acquired Resistance to Cisplatin in Small Cell Lung Cancer Cells.

    PubMed

    Yan, Fei; Pang, Jiuxia; Peng, Yong; Molina, Julian R; Yang, Ping; Liu, Shujun

    2016-01-01

    Although small cell lung cancer (SCLC) is highly responsive to chemotherapies (e.g., cisplatin-etoposide doublet), virtually almost all responsive SCLC patients experience disease recurrence characterized by drug resistance. The mechanisms underlying cisplatin resistance remain elusive. Here we report that cell-intrinsic expression of PD1 and PD-L1, two immune checkpoints, is required for sustained expansion of SCLC cells under cisplatin selection. Indeed, PD1 and PD-L1 were expressed at a higher level in lung cancer cell lines, tumor tissues, and importantly, in SCLC cells resistant to cisplatin (H69R, H82R), when compared to respective controls. Genetic abrogation of PD1 and PD-L1 in H69R and H82R cells decreased their proliferation rate, and restored their sensitivity to cisplatin. Mechanistically, PD-L1 upregulation in H69R and H82R cells was attributed to the overexpression of DNA methyltransferase 1 (DNMT1) or receptor tyrosine kinase KIT, as knockdown of DNMT1 or KIT in H69R and H82R cells led to PD-L1 downregulation. Consequently, combined knockdown of PD-L1 with KIT or DNMT1 resulted in more pronounced inhibition of H69R and H82R cell growth. Thus, cell intrinsic PD1/PD-L1 signaling may be a predictor for poor efficacy of cisplatin treatment, and targeting the cellular PD1/PD-L1 axis may improve chemosensitization of aggressive SCLC. PMID:27610620

  15. Continuous administration of bevacizumab plus capecitabine, even after acquired resistance to bevacizumab, restored anti-angiogenic and antitumor effect in a human colorectal cancer xenograft model

    PubMed Central

    Iwai, Toshiki; Sugimoto, Masamichi; Harada, Suguru; Yorozu, Keigo; Kurasawa, Mitsue; Yamamoto, Kaname

    2016-01-01

    Vascular endothelial growth factor (VEGF)-neutralizing therapy with bevacizumab has become increasingly important for treating colorectal cancer. It was demonstrated that second-line chemotherapy together with bevacizumab after disease progression (PD) on first-line therapy including bevacizumab showed clinical benefits in metastatic colorectal and breast cancers (ML18147 trial, TANIA trial). One of the rationales for these trials was that the refractoriness to first-line therapy is caused by resistance to not so much bevacizumab as to the chemotherapeutic agents. Nevertheless, resistance to bevacizumab cannot be ruled out because VEGF-independent angiogenesis has been reported to be a mechanism of resistance to anti-VEGF therapy. In this study, we used a xenograft model with the human colon cancer HT-29 cells to investigate the mechanisms underlying the effect of continued administration of bevacizumab plus capecitabine even after resistance to bevacizumab was acquired. The combination of capecitabine plus bevacizumab exhibited significantly stronger antitumor and anti-angiogenic activities than did monotherapy with either agent. Capecitabine treatment significantly increased the intratumoral VEGF level compared with the control group; however, the combination with bevacizumab neutralized the VEGF. Among angiogenic factors other than VEGF, intratumoral galectin-3, which reportedly promotes angiogenesis both dependent on, and independently of VEGF, was significantly decreased in the capecitabine group and the combination group compared with the control group. In an in vitro experiment, 5-fluorouracil (5-FU), an active metabolite of capecitabine, inhibited galectin-3 production by HT-29 cells. These results suggested that capecitabine has a dual mode of action: namely, inhibition of tumor cell growth and inhibition of galectin-3 production by tumor cells. Thus, capecitabine and bevacizumab may work in a mutually complementary manner in tumor angiogenesis inhibition

  16. BRCA1185delAG tumors may acquire therapy resistance through expression of RING-less BRCA1

    PubMed Central

    Drost, Rinske; Dhillon, Kiranjit K.; van der Gulden, Hanneke; van der Heijden, Ingrid; Brandsma, Inger; Cruz, Cristina; Chondronasiou, Dafni; Castroviejo-Bermejo, Marta; van der Burg, Eline; Wientjens, Ellen; Pieterse, Mark; Klijn, Christiaan; Klarenbeek, Sjoerd; Loayza-Puch, Fabricio; Elkon, Ran; van Deemter, Liesbeth; Rottenberg, Sven; van de Ven, Marieke; Dekkers, Dick H.W.; Demmers, Jeroen A.A.; Agami, Reuven; Balmaña, Judith; Taniguchi, Toshiyasu; Bouwman, Peter

    2016-01-01

    Heterozygous germline mutations in breast cancer 1 (BRCA1) strongly predispose women to breast cancer. BRCA1 plays an important role in DNA double-strand break (DSB) repair via homologous recombination (HR), which is important for tumor suppression. Although BRCA1-deficient cells are highly sensitive to treatment with DSB-inducing agents through their HR deficiency (HRD), BRCA1-associated tumors display heterogeneous responses to platinum drugs and poly(ADP-ribose) polymerase (PARP) inhibitors in clinical trials. It is unclear whether all pathogenic BRCA1 mutations have similar effects on the response to therapy. Here, we have investigated mammary tumorigenesis and therapy sensitivity in mice carrying the Brca1185stop and Brca15382stop alleles, which respectively mimic the 2 most common BRCA1 founder mutations, BRCA1185delAG and BRCA15382insC. Both the Brca1185stop and Brca15382stop mutations predisposed animals to mammary tumors, but Brca1185stop tumors responded markedly worse to HRD-targeted therapy than did Brca15382stop tumors. Mice expressing Brca1185stop mutations also developed therapy resistance more rapidly than did mice expressing Brca15382stop. We determined that both murine Brca1185stop tumors and human BRCA1185delAG breast cancer cells expressed a really interesting new gene domain–less (RING-less) BRCA1 protein that mediated resistance to HRD-targeted therapies. Together, these results suggest that expression of RING-less BRCA1 may serve as a marker to predict poor response to DSB-inducing therapy in human cancer patients. PMID:27454287

  17. Arabidopsis Auxin Mutants Are Compromised in Systemic Acquired Resistance and Exhibit Aberrant Accumulation of Various Indolic Compounds1[W][OA

    PubMed Central

    Truman, William M.; Bennett, Mark H.; Turnbull, Colin G.N.; Grant, Murray R.

    2010-01-01

    Systemic acquired resistance is a widespread phenomenon in the plant kingdom that confers heightened and often enduring immunity to a range of diverse pathogens. Systemic immunity develops through activation of plant disease resistance protein signaling networks following local infection with an incompatible pathogen. The accumulation of the phytohormone salicylic acid in systemically responding tissues occurs within days after a local immunizing infection and is essential for systemic resistance. However, our knowledge of the signaling components underpinning signal perception and the establishment of systemic immunity are rudimentary. Previously, we showed that an early and transient increase in jasmonic acid in distal responding tissues was central to effective establishment of systemic immunity. Based upon predicted transcriptional networks induced in naive Arabidopsis (Arabidopsis thaliana) leaves following avirulent Pseudomonas syringae challenge, we show that a variety of auxin mutants compromise the establishment of systemic immunity. Linking together transcriptional and targeted metabolite studies, our data provide compelling evidence for a role of indole-derived compounds, but not auxin itself, in the establishment and maintenance of systemic immunity. PMID:20081042

  18. Control of salicylic acid synthesis and systemic acquired resistance by two members of a plant-specific family of transcription factors

    PubMed Central

    Zhang, Yaxi; Xu, Shaohua; Ding, Pingtao; Wang, Dongmei; Cheng, Yu Ti; He, Jing; Gao, Minghui; Xu, Fang; Li, Yan; Zhu, Zhaohai; Li, Xin; Zhang, Yuelin

    2010-01-01

    Salicylic acid (SA) is a defense hormone required for both local and systemic acquired resistance (SAR) in plants. Pathogen infections induce SA synthesis through up-regulating the expression of Isochorismate Synthase 1 (ICS1), which encodes a key enzyme in SA production. Here we report that both SAR Deficient 1 (SARD1) and CBP60g are key regulators for ICS1 induction and SA synthesis. Whereas knocking out SARD1 compromises basal resistance and SAR, overexpression of SARD1 constitutively activates defense responses. In the sard1-1 cbp60g-1 double mutant, pathogen-induced ICS1 up-regulation and SA synthesis are blocked in both local and systemic leaves, resulting in compromised basal resistance and loss of SAR. Electrophoretic mobility shift assays showed that SARD1 and CBP60g represent a plant-specific family of DNA-binding proteins. Both proteins are recruited to the promoter of ICS1 in response to pathogen infections, suggesting that they control SA synthesis by regulating ICS1 at the transcriptional level. PMID:20921422

  19. Spontaneous Healing of Corneal Perforation after Temporary Discontinuation of Erlotinib Treatment

    PubMed Central

    Morishige, Naoyuki; Hatabe, Nanami; Morita, Yukiko; Yamada, Naoyuki; Kimura, Kazuhiro; Sonoda, Koh-Hei

    2014-01-01

    Purpose To report a case of corneal perforation associated with oral administration of erlotinib and its spontaneous healing after temporary discontinuation of drug treatment. Case Report A 65-year-old man with metastatic lung cancer was treated with erlotinib (150 mg/day), a specific tyrosine kinase inhibitor of the epidermal growth factor receptor. He was referred to our corneal service for the treatment of bilateral corneal disorders, diagnosed with mild aqueous-deficient dry eye, and treated by insertion of punctal plugs. His corneal epithelial disorders initially improved, but subsequently worsened, as manifested by the development of bilateral corneal ulceration with corneal perforation in the right eye. The oral administration of erlotinib was interrupted in preparation for tectonic keratoplasty, but 2 days later the corneal perforation of the right eye and the bilateral epithelial defects had healed spontaneously. Treatment with erlotinib was resumed at half the initial dose, and the cornea of both eyes has remained apparently healthy. Discussion Erlotinib may be secreted into tear fluid and thereby adversely affect the corneal epithelium. The development of corneal epithelial disorders in patients receiving this drug may be reversed by reducing its dose. PMID:24575032

  20. Acquired lymphangiectasis.

    PubMed

    Celis, A V; Gaughf, C N; Sangueza, O P; Gourdin, F W

    1999-01-01

    Acquired lymphangiectasis is a dilatation of lymphatic vessels that can result as a complication of surgical intervention and radiation therapy for malignancy. Acquired lymphangiectasis shares clinical and histologic features with the congenital lesion, lymphangioma circumscriptum. Diagnosis and treatment of these vesiculo-bullous lesions is important because they may be associated with pain, chronic drainage, and cellulitis. We describe two patients who had these lesions after treatment for cancer and review the pertinent literature. Although a number of treatment options are available, we have found CO2 laser ablation particularly effective. PMID:9932832

  1. Invasive Community-Acquired Methicillin-Resistant Staphylococcus aureus in a Japanese Girl with Disseminating Multiple Organ Infection: A Case Report and Review of Japanese Pediatric Cases

    PubMed Central

    Yonezawa, Ryuta; Kuwana, Tsukasa; Kawamura, Kengo; Inamo, Yasuji

    2015-01-01

    Pediatric invasive community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infection is very serious and occasionally fatal. This infectious disease is still a relatively rare and unfamiliar infectious disease in Japan. We report a positive outcome in a 23-month-old Japanese girl with meningitis, osteomyelitis, fasciitis, necrotizing pneumonia, urinary tract infection, and bacteremia due to CA-MRSA treated with linezolid. PCR testing of the CA-MRSA strain was positive for PVL and staphylococcal enterotoxin b and negative for ACME. SCC mec was type IVa. This case underscores the selection of effective combinations of antimicrobial agents for its treatment. We need to be aware of invasive CA-MRSA infection, which rapidly progresses with a serious clinical course, because the incidence of the disease may be increasing in Japan. PMID:26819794

  2. Recurrence of pelvic abscess from Panton-Valentine leukocidin-positive community-acquired ST30 methicillin-resistant Staphylococcus aureus.

    PubMed

    Isobe, Hirokazu; Miyasaka, Dai; Ito, Tomoyuki; Takano, Tomomi; Nishiyama, Akihito; Iwao, Yasuhisa; Khokhlova, Olga E; Okubo, Takeshi; Endo, Naoto; Yamamoto, Tatsuo

    2013-02-01

    A 17-year-old female patient (a basketball player) suffered from recurrent pelvic abscesses from methicillin-resistant Staphylococcus aureus (MRSA). The first episode, from strain NN12, occurred in October 2004. Her cutaneous abscesses complicated into systemic progression to osteomyelitis and multifocal pelvic abscesses, adjacent to the sacroiliac joint. The second episode, abscesses at tissues adjacent to the sacroiliac joint from strain NN31A, occurred late in February 2005. The third episode, from strain NN31B, occurred on July 30, 2005, repeating the second episode. Three MRSA strains were identical in terms of genotypes (belonging to Panton-Valentine leukocidin [PVL]-positive ST30 community-acquired MRSA, CA-MRSA), pulsed-field gel electrophoresis patterns, and peptide cytolysin gene (psmα) expression levels. The three MRSA strains exhibited superior THP-1 cell invasion ability over hospital-acquired MRSA (New York/Japan clone). The data suggest that PVL-positive ST30 CA-MRSA, with high levels of cell invasion and peptide cytolysins, causes recurrence of pelvic abscesses in a healthy adolescent.

  3. Hospital Acquired Pneumonia Due to Achromobacter spp. in a Geriatric Ward in China: Clinical Characteristic, Genome Variability, Biofilm Production, Antibiotic Resistance and Integron in Isolated Strains

    PubMed Central

    Liu, Chao; Pan, Fei; Guo, Jun; Yan, Weifeng; Jin, Yi; Liu, Changting; Qin, Long; Fang, Xiangqun

    2016-01-01

    Background: Hospital-acquired pneumonia (HAP) due to Achromobacter has become a substantial concern in recent years. However, HAP due to Achromobacter in the elderly is rare. Methods: A retrospective analysis was performed on 15 elderly patients with HAP due to Achromobacter spp., in which the sequence types (STs), integrons, biofilm production and antibiotic resistance of the Achromobacter spp. were examined. Results: The mean age of the 15 elderly patients was 88.8 ± 5.4 years. All patients had at least three underlying diseases and catheters. Clinical outcomes improved in 10 of the 15 patients after antibiotic and/or mechanical ventilation treatment, but three patients had chronic infections lasting more than 1 year. The mortality rate was 33.3% (5/15). All strains were resistant to aminoglycosides, aztreonam, nitrofurantoin, and third- and fourth-generation cephalosporins (except ceftazidime and cefoperazone). Six new STs were detected. The most frequent ST was ST306. ST5 was identified in two separate buildings of the hospital. ST313 showed higher MIC in cephalosporins, quinolones and carbapenems, which should be more closely considered in clinical practice. All strains produced biofilm and had integron I and blaOXA-114-like. The main type was blaOXA-114q. The variable region of integron I was different among strains, and the resistance gene of the aminoglycosides was most commonly inserted in integron I. Additionally, blaPSE-1 was first reported in this isolate. Conclusion: Achromobacter spp. infection often occurs in severely ill elders with underlying diseases. The variable region of integrons differs, suggesting that Achromobacter spp. is a reservoir of various resistance genes. PMID:27242678

  4. Acquired resistance of Nocardia brasiliensis to clavulanic acid related to a change in beta-lactamase following therapy with amoxicillin-clavulanic acid.

    PubMed Central

    Steingrube, V A; Wallace, R J; Brown, B A; Pang, Y; Zeluff, B; Steele, L C; Zhang, Y

    1991-01-01

    Previous studies have demonstrated that Nocardia brasiliensis is susceptible to amoxicillin-clavulanic acid and that its beta-lactamases are inhibited in vitro by clavulanic acid. A cardiac transplant patient with disseminated infection caused by N. brasiliensis was treated with this drug combination with good response, but relapsed while still on therapy. The relapse isolate was found to be identical to the initial isolate by using genomic DNA restriction fragment patterns obtained by pulsed field gel electrophoresis, but it was resistant to amoxicillin-clavulanic acid. On isoelectric focusing, the beta-lactamase from the relapse isolate exhibited a shift in the isoelectric point (pI) of its major band from 5.10 to 5.04 compared with the enzyme from the pretreatment isolate. As determined by using values of the amount of beta-lactamase inhibitor necessary to give 50 +/- 5% inhibition of beta-lactamase-mediated hydrolysis of 50 microM nitrocefin, the beta-lactamase of the relapse isolate was also 200-fold more resistant than the enzyme from the pretreatment isolate to clavulanic acid and was more resistant to sulbactam, tazobactam, cloxacillin, and imipenem. The beta-lactamase of the relapse isolate exhibited a 10-fold decrease in hydrolytic activity for cephaloridine and other hydrolyzable cephalosporins compared with that for nitrocefin. Acquired resistance to amoxicillin-clavulanic acid in this isolate of N. brasiliensis appears to have resulted from a mutational change affecting the inhibitor and active site(s) in the beta-lactamase. Images PMID:2039203

  5. Chromosomal integration of a cephalosporinase gene from Acinetobacter baumannii into Oligella urethralis as a source of acquired resistance to beta-lactams.

    PubMed

    Mammeri, Hedi; Poirel, Laurent; Mangeney, Nicole; Nordmann, Patrice

    2003-05-01

    Clinical Oligella urethralis isolate COH-1, which was uncommonly resistant to penicillins and narrow-spectrum cephalosporins, was recovered from a 55-year-old patient with a urinary tract infection. Shotgun cloning into Escherichia coli and expression experiments gave recombinant clones expressing either an AmpC beta-lactamase-type phenotype of resistance or a carbenicillin-hydrolyzing beta-lactamase-type phenotype of resistance. The AmpC beta-lactamase identified (ABA-1), which had a pI value of 8.2, had 98% amino acid identity with a chromosomally encoded cephalosporinase of Acinetobacter baumannii. A 820-bp insertion sequence element, ISOur1, belonging to the IS6 family of insertion sequence elements, was identified immediately upstream of bla(ABA-1), providing a -35 promoter sequence and likely giving rise to a hybrid promoter region. The carbenicillin-hydrolyzing beta-lactamase identified (CARB-8), which had a pI value of 6.4, differed from CARB-5 by two amino acid substitutions. Hybridization of CeuI fragment I-restricted DNA fragments of O. urethralis COH-1 with bla(ABA-1)-, bla(CARB-8)-, and 16S rRNA-specific probes indicated the chromosomal integration of the beta-lactamase genes. PCR and hybridization experiments failed to detect bla(CARB-8)- and bla(ABA-1)-like genes in three O. urethralis reference strains, indicating that the beta-lactamase genes identified were the source of acquired resistance in O. urethralis COH-1. This is one of the few examples of the interspecies transfer and the chromosomal integration of a gene encoding a naturally occurring beta-lactamase.

  6. High prevalence of hospital-acquired infections caused by gram-negative carbapenem resistant strains in Vietnamese pediatric ICUs: A multi-centre point prevalence survey.

    PubMed

    Le, Ngai Kien; Hf, Wertheim; Vu, Phu Dinh; Khu, Dung Thi Khanh; Le, Hai Thanh; Hoang, Bich Thi Ngoc; Vo, Vu Thanh; Lam, Yen Minh; Vu, Dung Tien Viet; Nguyen, Thu Hoai; Thai, Tung Quang; Nilsson, Lennart E; Rydell, Ulf; Nguyen, Kinh Van; Nadjm, Behzad; Clarkson, Louise; Hanberger, Håkan; Larsson, Mattias

    2016-07-01

    There is scarce information regarding hospital-acquired infections (HAIs) among children in resource-constrained settings. This study aims to measure prevalence of HAIs in Vietnamese pediatric hospitals.Monthly point prevalence surveys (PPSs) in 6 pediatric intensive care units (ICUs) in 3 referral hospitals during 1 year.A total of 1363 cases (1143 children) were surveyed, 59.9% male, average age 11 months. Admission sources were: other hospital 49.3%, current hospital 36.5%, and community 15.3%. Reasons for admission were: infectious disease (66%), noninfectious (20.8%), and surgery/trauma (11.3%). Intubation rate was 47.8%, central venous catheter 29.4%, peripheral venous catheter 86.2%, urinary catheter 14.6%, and hemodialysis/filtration 1.7%. HAI was diagnosed in 33.1% of the cases: pneumonia (52.2%), septicemia (26.4%), surgical site infection (2%), and necrotizing enterocolitis (2%). Significant risk factors for HAI included age under 7 months, intubation and infection at admission. Microbiological findings were reported in 212 cases (43%) with 276 isolates: 50 Klebsiella pneumoniae, 46 Pseudomonas aeruginosa, and 39 Acinetobacter baumannii, with carbapenem resistance detected in 55%, 71%, and 65%, respectively. Staphylococcus aureus was cultured in 18 cases, with 81% methicillin-resistant Staphylococcus aureus. Most children (87.6%) received antibiotics, with an average of 1.6 antibiotics per case. Colistin was administered to 96 patients, 93% with HAI and 49% with culture confirmed carbapenem resistance.The high prevalence of HAI with carbapenem resistant gram-negative strains and common treatment with broad-spectrum antibiotics and colistin suggests that interventions are needed to prevent HAI and to optimize antibiotic use. PMID:27399106

  7. Acquired Tumor Cell Radiation Resistance at the Treatment Site Is Mediated Through Radiation-Orchestrated Intercellular Communication

    SciTech Connect

    Aravindan, Natarajan; Aravindan, Sheeja; Pandian, Vijayabaskar; Khan, Faizan H.; Ramraj, Satish Kumar; Natt, Praveen; Natarajan, Mohan

    2014-03-01

    Purpose: Radiation resistance induced in cancer cells that survive after radiation therapy (RT) could be associated with increased radiation protection, limiting the therapeutic benefit of radiation. Herein we investigated the sequential mechanistic molecular orchestration involved in radiation-induced radiation protection in tumor cells. Results: Radiation, both in the low-dose irradiation (LDIR) range (10, 50, or 100 cGy) or at a higher, challenge dose IR (CDIR), 4 Gy, induced dose-dependent and sustained NFκB-DNA binding activity. However, a robust and consistent increase was seen in CDIR-induced NFκB activity, decreased DNA fragmentation, apoptosis, and cytotoxicity and attenuation of CDIR-inhibited clonal expansion when the cells were primed with LDIR prior to challenge dose. Furthermore, NFκB manipulation studies with small interfering RNA (siRNA) silencing or p50/p65 overexpression unveiled the influence of LDIR-activated NFκB in regulating CDIR-induced DNA fragmentation and apoptosis. LDIR significantly increased the transactivation/translation of the radiation-responsive factors tumor necrosis factor-α (TNF-α), interleukin-1α (IL-1α), cMYC, and SOD2. Coculture experiments exhibit LDIR-influenced radiation protection and increases in cellular expression, secretion, and activation of radiation-responsive molecules in bystander cells. Individual gene-silencing approach with siRNAs coupled with coculture studies showed the influence of LDIR-modulated TNF-α, IL-1α, cMYC, and SOD2 in induced radiation protection in bystander cells. NFκB inhibition/overexpression studies coupled with coculture experiments demonstrated that TNF-α, IL-1α, cMYC, and SOD2 are selectively regulated by LDIR-induced NFκB. Conclusions: Together, these data strongly suggest that scattered LDIR-induced NFκB-dependent TNF-α, IL-1α, cMYC, and SOD2 mediate radiation protection to the subsequent challenge dose in tumor cells.

  8. Acquired resistance to metformin in breast cancer cells triggers transcriptome reprogramming toward a degradome-related metastatic stem-like profile

    PubMed Central

    Oliveras-Ferraros, Cristina; Vazquez-Martin, Alejandro; Cuyàs, Elisabet; Corominas-Faja, Bruna; Rodríguez-Gallego, Esther; Fernández-Arroyo, Salvador; Martin-Castillo, Begoña; Joven, Jorge; Menendez, Javier A

    2014-01-01

    Therapeutic interventions based on metabolic inhibitor-based therapies are expected to be less prone to acquired resistance. However, there has not been any study assessing the possibility that the targeting of the tumor cell metabolism may result in unforeseeable resistance. We recently established a pre-clinical model of estrogen-dependent MCF-7 breast cancer cells that were chronically adapted to grow (> 10 months) in the presence of graded, millimolar concentrations of the anti-diabetic biguanide metformin, an AMPK agonist/mTOR inhibitor that has been evaluated in multiple in vitro and in vivo cancer studies and is now being tested in clinical trials. To assess what impact the phenomenon of resistance might have on the metformin-like “dirty” drugs that are able to simultaneously hit several metabolic pathways, we employed the ingenuity pathway analysis (IPA) software to functionally interpret the data from Agilent whole-human genome arrays in the context of biological processes, networks, and pathways. Our findings establish, for the first time, that a “global” targeting of metabolic reprogramming using metformin certainly imposes a great selective pressure for the emergence of new breast cancer cellular states. Intriguingly, acquired resistance to metformin appears to trigger a transcriptome reprogramming toward a metastatic stem-like profile, as many genes encoding the components of the degradome (KLK11, CTSF, FREM1, BACE-2, CASP, TMPRSS4, MMP16, HTRA1), cancer cell migration and invasion factors (TP63, WISP2, GAS3, DKK1, BCAR3, PABPC1, MUC1, SPARCL1, SEMA3B, SEMA6A), stem cell markers (DCLK1, FAK), and key pro-metastatic lipases (MAGL and Cpla2) were included in the signature. Because this convergent activation of pathways underlying tumor microenvironment interactions occurred in low-proliferative cancer cells exhibiting a notable downregulation of the G2/M DNA damage checkpoint regulators that maintain genome stability (CCNB1, CCNB2, CDC20, CDC25C

  9. Acquired resistance to metformin in breast cancer cells triggers transcriptome reprogramming toward a degradome-related metastatic stem-like profile.

    PubMed

    Oliveras-Ferraros, Cristina; Vazquez-Martin, Alejandro; Cuyàs, Elisabet; Corominas-Faja, Bruna; Rodríguez-Gallego, Esther; Fernández-Arroyo, Salvador; Martin-Castillo, Begoña; Joven, Jorge; Menendez, Javier A

    2014-01-01

    Therapeutic interventions based on metabolic inhibitor-based therapies are expected to be less prone to acquired resistance. However, there has not been any study assessing the possibility that the targeting of the tumor cell metabolism may result in unforeseeable resistance. We recently established a pre-clinical model of estrogen-dependent MCF-7 breast cancer cells that were chronically adapted to grow (> 10 months) in the presence of graded, millimolar concentrations of the anti-diabetic biguanide metformin, an AMPK agonist/mTOR inhibitor that has been evaluated in multiple in vitro and in vivo cancer studies and is now being tested in clinical trials. To assess what impact the phenomenon of resistance might have on the metformin-like "dirty" drugs that are able to simultaneously hit several metabolic pathways, we employed the ingenuity pathway analysis (IPA) software to functionally interpret the data from Agilent whole-human genome arrays in the context of biological processes, networks, and pathways. Our findings establish, for the first time, that a "global" targeting of metabolic reprogramming using metformin certainly imposes a great selective pressure for the emergence of new breast cancer cellular states. Intriguingly, acquired resistance to metformin appears to trigger a transcriptome reprogramming toward a metastatic stem-like profile, as many genes encoding the components of the degradome (KLK11, CTSF, FREM1, BACE-2, CASP, TMPRSS4, MMP16, HTRA1), cancer cell migration and invasion factors (TP63, WISP2, GAS3, DKK1, BCAR3, PABPC1, MUC1, SPARCL1, SEMA3B, SEMA6A), stem cell markers (DCLK1, FAK), and key pro-metastatic lipases (MAGL and Cpla2) were included in the signature. Because this convergent activation of pathways underlying tumor microenvironment interactions occurred in low-proliferative cancer cells exhibiting a notable downregulation of the G 2/M DNA damage checkpoint regulators that maintain genome stability (CCNB1, CCNB2, CDC20, CDC25C, AURKA

  10. NOX4 mediates cytoprotective autophagy induced by the EGFR inhibitor erlotinib in head and neck cancer cells

    SciTech Connect

    Sobhakumari, Arya; Schickling, Brandon M.; Love-Homan, Laurie; Raeburn, Ayanna; Fletcher, Elise V.M.; Case, Adam J.; Domann, Frederick E.; Miller, Francis J.; and others

    2013-11-01

    Most head and neck squamous cell carcinomas (HNSCCs) overexpress epidermal growth factor receptor (EGFR) and EGFR inhibitors are routinely used in the treatment of HNSCC. However, many HNSCC tumors do not respond or become refractory to EGFR inhibitors. Autophagy, which is a stress-induced cellular self-degradation process, has been reported to reduce the efficacy of chemotherapy in various disease models. The purpose of this study is to determine if the efficacy of the EGFR inhibitor erlotinib is reduced by activation of autophagy via NOX4-mediated oxidative stress in HNSCC cells. Erlotinib induced the expression of the autophagy marker LC3B-II and autophagosome formation in FaDu and Cal-27 cells. Inhibition of autophagy by chloroquine and knockdown of autophagy pathway genes Beclin-1 and Atg5 sensitized both cell lines to erlotinib-induced cytotoxicity, suggesting that autophagy may serve as a protective mechanism. Treatment with catalase (CAT) and diphenylene iodonium (DPI) in the presence of erlotinib suppressed the increase in LC3B-II expression in FaDu and Cal-27 cells. Erlotinib increased NOX4 mRNA and protein expression by increasing its promoter activity and mRNA stability in FaDu cells. Knockdown of NOX4 using adenoviral siNOX4 partially suppressed erlotinib-induced LC3B-II expression, while overexpression of NOX4 increased expression of LC3B-II. These studies suggest that erlotinib may activate autophagy in HNSCC cells as a pro-survival mechanism, and NOX4 may play a role in mediating this effect. - Highlights: • Erlotinib increased LC3B-II and autophagosome formation in HNSCC cells. • Inhibition of autophagy sensitized HNSCC cells to erlotinib. • Erlotinib increased NOX4 promoter and 3′UTR luciferase activity. • Manipulating NOX4 decreases or increases autophagy.

  11. Determination of Acquired Resistance Profiles of Pseudomonas aeruginosa Isolates and Characterization of an Effective Bacteriocin-Like Inhibitory Substance (BLIS) Against These Isolates

    PubMed Central

    Shokri, Dariush; Rabbani Khorasgani, Mohammad; Zaghian, Saeideh; Fatemi, Seyed Masih; Mohkam, Milad; Ghasemi, Younes; Taheri-Kafrani, Asghar

    2016-01-01

    Background The emergence of pan-drug resistant strains (PDR) of Pseudomonas aeruginosa has led to renewed efforts to identify alternative agents, such as bacteriocins and bacteriocin-like inhibitory substances (BLISs). Objectives The aims of this study were to determine the acquired resistance profiles of multidrug-resistant (MDR), extensively drug-resistant (XDR), and PDR P. aeruginosa isolates based on the revised definitions of the CDC and ECDC and to screen and characterize effective BLISs against these isolates. Patients and Materials In a cross-sectional study, 96 P. aeruginosa strains were isolated during a 12-month period. The resistance profiles of these isolates were determined as MDR, XDR, and PDR, and the data were analyzed using WHONET5.6 software. A BLIS against the P. aeruginosa strains was characterized based on its physicochemical properties, size, growth curves, and production profiles. Results Among the 96 isolates of P. aeruginosa, 2 (2.1%), 94 (97.9%), and 63 (65.6%) were non-MDR, MDR, and XDR, respectively, and 1 (1.1%) was PDR. The most effective antibiotics against these isolates were polymyxins and fosfomycin. A BLIS isolated from the P. aeruginosa DSH22 strain had potent activity against 92 (95.8%) of the 96 isolates. The BLIS was heat stable, (up to 100°C for 10 min), UV stable, and active within a pH range of 3 - 9. The activity of BLIS disappeared when treated with trypsin, proteinase K, and pepsin, indicating its proteinous nature. Based on its size (25 kDa), the BLIS may belong to the large colicin-like bacteriocin family. BLIS production started in the midexponential phase of growth, and the maximum level (2700 AU/mL) occurred in the late-stationary phase after 25 hours of incubation at 30°C. Conclusions This BLIS with broad-spectrum activity may be a potential agent for the treatment or control of drug-resistant strains of P. aeruginosa infection. PMID:27800131

  12. Acquired resistance to acetaminophen hepatotoxicity is associated with induction of multidrug resistance-associated protein 4 (Mrp4) in proliferating hepatocytes.

    PubMed

    Aleksunes, Lauren M; Campion, Sarah N; Goedken, Michael J; Manautou, José E

    2008-08-01

    Treatment with hepatotoxicants such as acetaminophen (APAP) causes resistance to a second, higher dose of the same toxicant (autoprotection). APAP induces hepatic mRNA and protein levels of the multidrug resistance-associated proteins (Mrp) transporters in mice and humans. Basolateral efflux transporters Mrp3 and Mrp4 are the most significantly induced. We hypothesized that upregulation of Mrp3 and Mrp4 is one mechanism by which hepatocytes become resistant to a subsequent higher dose of APAP by limiting accumulation of xeno-, endobiotics, and byproducts of hepatocellular injury. The purpose of this study was to evaluate Mrp3 and Mrp4 expression in proliferating hepatocytes in a mouse model of APAP autoprotection. Plasma and livers were collected from male C57BL/6J mice treated with APAP 400 mg/kg for determination of hepatotoxicity and protein expression. Maximal Mrp3 and Mrp4 induction occurred 48 h after APAP. Mrp4 upregulation occurred selectively in proliferating hepatocytes. Additional groups of APAP-pretreated mice were challenged 48 h later with a second, higher dose of APAP. APAP-pretreated mice had reduced hepatotoxicity after APAP challenge compared to those pretreated with vehicle. A more rapid recovery of glutathione (GSH) in APAP-pretreated mice corresponded with increases in GSH synthetic enzymes. Interestingly, mice pretreated and challenged with APAP had dramatic increases in Mrp4 expression as well as enhanced hepatocyte proliferation. Inhibition of hepatocyte replication with colchicine not only restored sensitivity of APAP-pretreated mice to injury, but also blocked Mrp4 induction. Mrp4 overexpression may be one phenotypic property of proliferating hepatocytes that protects against subsequent hepatotoxicant exposure by mechanisms that are presently unknown. PMID:18468992

  13. Sustained Response of a Clivus Chordoma to Erlotinib after Imatinib Failure

    PubMed Central

    Houessinon, Aline; Boone, Mathieu; Constans, Jean-Marc; Toussaint, Patrick; Chauffert, Bruno

    2015-01-01

    Chordoma is a rare malignant axial tumour that develops from embryonic remnants of the notochord. Surgery and irradiation are the standard initial treatment. However, local recurrence is frequent and cytotoxic chemotherapy is inefficient. Transient activity of imatinib, a platelet-derived growth factor receptor inhibitor, was described in a phase II study. Activity of epidermal growth factor receptor (EGFR) inhibitors (erlotinib, gefitinib) has also been shown in a few recent case reports. We describe a 68-year-old female in whom clivus chordoma recurred after surgery and radiotherapy. The tumour progressed despite imatinib treatment. A partial and sustained response (28+ months) was obtained using erlotinib, an EGFR inhibitor. Erlotinib should be evaluated in a prospective trial investigating new potential therapies against recurrent chordoma. PMID:25762924

  14. The Arabidopsis Mediator Complex Subunit16 Positively Regulates Salicylate-Mediated Systemic Acquired Resistance and Jasmonate/Ethylene-Induced Defense Pathways[W

    PubMed Central

    Zhang, Xudong; Wang, Chenggang; Zhang, Yanping; Sun, Yijun; Mou, Zhonglin

    2012-01-01

    Systemic acquired resistance (SAR) is a long-lasting plant immunity against a broad spectrum of pathogens. Biological induction of SAR requires the signal molecule salicylic acid (SA) and involves profound transcriptional changes that are largely controlled by the transcription coactivator NONEXPRESSOR OF PATHOGENESIS-RELATED GENES1 (NPR1). However, it is unclear how SAR signals are transduced from the NPR1 signaling node to the general transcription machinery. Here, we report that the Arabidopsis thaliana Mediator subunit16 (MED16) is an essential positive regulator of SAR. Mutations in MED16 reduced NPR1 protein levels and completely compromised biological induction of SAR. These mutations also significantly suppressed SA-induced defense responses, altered the transcriptional changes induced by the avirulent bacterial pathogen Pseudomonas syringae pv tomato (Pst) DC3000/avrRpt2, and rendered plants susceptible to both Pst DC3000/avrRpt2 and Pst DC3000. In addition, mutations in MED16 blocked the induction of several jasmonic acid (JA)/ethylene (ET)–responsive genes and compromised resistance to the necrotrophic fungal pathogens Botrytis cinerea and Alternaria brassicicola. The Mediator complex acts as a bridge between specific transcriptional activators and the RNA polymerase II transcription machinery; therefore, our data suggest that MED16 may be a signaling component in the gap between the NPR1 signaling node and the general transcription machinery and may relay signals from both the SA and the JA/ET pathways. PMID:23064320

  15. Increasing antimicrobial resistance in Escherichia coli isolates from community-acquired urinary tract infections during 1998-2003 in Manisa, Turkey.

    PubMed

    Kurutepe, Semra; Surucuoglu, Suheyla; Sezgin, Cenk; Gazi, Horu; Gulay, Mehmet; Ozbakkaloglu, Beril

    2005-06-01

    Urinary tract infections are among the most common infections with an increasing resistance to antimicrobials. The aim of this study was to determine the change in antimicrobial susceptibility of Escherichia coli isolates from patients with community-acquired urinary tract infection (UTI) for the years 1998 through 2003 and to suggest that the current empirical antibiotic therapy used for these patients is inappropriate. During the study period, 7,335 community urine samples of which 1,203 (16.4%) grew bacterial isolates were analyzed. Among the total of 1,203 isolates, 880 (73.2%) were E. coli. The range of resistance of E. coli to ampicillin was 47.8 to 64.6% and that to trimethoprim-sulfamethoxazole was 37.1 to 44.6% during the study period. The susceptibility pattern of E. coli to nitrofurantoin and cefuroxime did not vary significantly over the 6-year period. There was a significant increase in the susceptibility of E. coli to ciprofloxacin (11.3 - 26.7%), amoxicillin-clavulanate (18.4 - 29.2%) and gentamicin (7.0 - 25.6%) (P < 0.05). Empirical initial treatment with ampicillin and trimethoprim-sulfamethoxazole was thus inadequate in approximately half of UTI cases in our region.

  16. Incidence of community-acquired methicillin-resistant Staphylococcus aureus carrying Pantone-Valentine leucocidin gene at a referral hospital in United Arab Emirates.

    PubMed

    Dash, Nihar; Panigrahi, Debadatta; Al Zarouni, Mansour; Yassin, Faten; Al-Shamsi, Moza

    2014-04-01

    Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) is an emerging pathogen in hospitalized patients worldwide. The present study was undertaken to identify CA-MRSA in hospitalized patients in a 350-bed tertiary care hospital in Sharjah, UAE over a 2-year period from January 2011 to December 2012. CA-MRSA was defined based on identification within first 48 h of admission in the hospital. Staphylococcal cassette chromosome (SCC) mec typing of the CA-MRSA isolates was carried out by multiplex polymerase chain reaction (PCR). Detection of PVL and mecA genes was done by PCR using the GenoType(®) MRSA test system (Hain Lifescience). Patient's clinical data and antimicrobial susceptibility pattern of the CA-MRSA isolates were also evaluated. Fifty seven of the 187 MRSA isolates were identified as CA-MRSA. All the CA-MRSA strains in our study belonged to SCCmecIV type and were positive for both PVL and mecA genes. The patients with CA-MRSA infections were young (median age, 32 years) and the majority of infections involved the skin and soft tissue (36%). Antimicrobial susceptibility pattern of the CA-MRSA isolates showed a better susceptibility profile to the non-beta-lactam antimicrobials with the exception of ciprofloxacin having 28% resistance. This study evidently strengthens the recent observation of an increase in CA-MRSA emergence among hospitalized patients in the UAE. PMID:23919760

  17. Brush and Spray: A High-Throughput Systemic Acquired Resistance Assay Suitable for Large-Scale Genetic Screening1[W][OA

    PubMed Central

    Jing, Beibei; Xu, Shaohua; Xu, Mo; Li, Yan; Li, Shuxin; Ding, Jinmei; Zhang, Yuelin

    2011-01-01

    Systemic acquired resistance (SAR) is a defense mechanism induced in the distal parts of plants after primary infection. It confers long-lasting protection against a broad spectrum of microbial pathogens. Lack of high-throughput assays has hampered the forward genetic analysis of SAR. Here, we report the development of an easy and efficient assay for SAR and its application in a forward genetic screen for SAR-deficient mutants in Arabidopsis (Arabidopsis thaliana). Using the new assay for SAR, we identified six flavin-dependent monooxygenase1, four AGD2-like defense response protein1, three salicylic acid induction-deficient2, one phytoalexin deficient4, and one avrPphB-susceptible3 alleles as well as a gain-of-function mutant of CALMODULIN-BINDING TRANSCRIPTION ACTIVATOR3 designated camta3-3D. Like transgenic plants overexpressing CAMTA3, camta3-3D mutant plants exhibit compromised SAR and enhanced susceptibility to virulent pathogens, suggesting that CAMTA3 is a critical regulator of both basal resistance and SAR. PMID:21900483

  18. Estrogen receptor-α36 is involved in development of acquired tamoxifen resistance via regulating the growth status switch in breast cancer cells.

    PubMed

    Li, Guangliang; Zhang, Jing; Jin, Ketao; He, Kuifeng; Zheng, Yi; Xu, Xin; Wang, Haohao; Wang, Haiyong; Li, Zhongqi; Yu, Xiongfei; Teng, Xiaodong; Cao, Jiang; Teng, Lisong

    2013-06-01

    Acquired tamoxifen (TAM) resistance limits the therapeutic benefit of TAM in patients with hormone-dependent breast cancer. The switch from estrogen-dependent to growth factor-dependent growth is a critical step in this process. However, the molecular mechanisms underlying this switch remain poorly understood. In this study, we established a TAM resistant cell sub line (MCF-7/TAM) from estrogen receptor-α (ER-α66) positive breast cancer MCF-7 cells by culturing ER-α66-positive MCF-7 cells in medium plus 1 μM TAM over 6 months. MCF-7/TAM cells were then found to exhibit accelerated proliferation rate together with enhanced in vitro migratory and invasive ability. And the estrogen receptor-α36 (ER-α36), a novel 36-kDa variant of ER-α66, was dramatically overexpressed in this in vitro model, compared to the parental MCF-7 cells. Meanwhile, the expression of epidermal growth factor receptor (EGFR) in MCF-7/TAM cells was significantly up-regulated both in mRNA level and protein level, and the expression of ER-α66 was greatly down-regulated oppositely. In the subsequent studies, we overexpressed ER-α36 in MCF-7 cells by stable transfection and found that ER-α36 transfected MCF-7 cells (MCF-7/ER-α36) similarly exhibited decreased sensitivity to TAM, accelerated proliferative rate and enhanced in vitro migratory and invasive ability, compared to empty vector transfected MCF-7 cells (MCF-7/V). Real-time qPCR and Western blotting analysis revealed that MCF-7/ER-α36 cells possessed increased EGFR expression but decreased ER-α66 expression both in mRNA level and protein level, compared to MCF-7/V cells. This change in MCF-7/ER-α36 cells could be reversed by neutralizing anti-ER-α36 antibody treatment. Furthermore, knock-down of ER-α36 expression in MCF-7/TAM cells resulted in reduced proliferation rate together with decreased in vitro migratory and invasive ability. Decreased EGFR mRNA and protein expression as well as increased ER-α66 mRNA expression were

  19. Acquired hyperpigmentations*

    PubMed Central

    Cestari, Tania Ferreira; Dantas, Lia Pinheiro; Boza, Juliana Catucci

    2014-01-01

    Cutaneous hyperpigmentations are frequent complaints, motivating around 8.5% of all dermatological consultations in our country. They can be congenital, with different patterns of inheritance, or acquired in consequence of skin problems, systemic diseases or secondary to environmental factors. The vast majority of them are linked to alterations on the pigment melanin, induced by different mechanisms. This review will focus on the major acquired hyperpigmentations associated with increased melanin, reviewing their mechanisms of action and possible preventive measures. Particularly prominent aspects of diagnosis and therapy will be emphasized, with focus on melasma, post-inflammatory hyperpigmentation, periorbital pigmentation, dermatosis papulosa nigra, phytophotodermatoses, flagellate dermatosis, erythema dyschromicum perstans, cervical poikiloderma (Poikiloderma of Civatte), acanthosis nigricans, cutaneous amyloidosis and reticulated confluent dermatitis PMID:24626644

  20. Initial use of one or two antibiotics for critically ill patients with community-acquired pneumonia: impact on survival and bacterial resistance

    PubMed Central

    2013-01-01

    Introduction Several guidelines recommend initial empirical treatment with two antibiotics instead of one to decrease mortality in community-acquired pneumonia (CAP) requiring intensive-care-unit (ICU) admission. We compared the impact on 60-day mortality of using one or two antibiotics. We also compared the rates of nosocomial pneumonia and multidrug-resistant bacteria. Methods This is an observational cohort study of 956 immunocompetent patients with CAP admitted to ICUs in France and entered into a prospective database between 1997 and 2010. Patients with chronic obstructive pulmonary disease were excluded. Multivariate analysis adjusted for disease severity, gender, and co-morbidities was used to compare the impact on 60-day mortality of receiving adequate initial antibiotics and of receiving one versus two initial antibiotics. Results Initial adequate antibiotic therapy was significantly associated with better survival (subdistribution hazard ratio (sHR), 0.63; 95% confidence interval (95% CI), 0.42 to 0.94; P = 0.02); this effect was strongest in patients with Streptococcus pneumonia CAP (sHR, 0.05; 95% CI, 0.005 to 0.46; p = 0.001) or septic shock (sHR: 0.62; 95% CI 0.38 to 1.00; p = 0.05). Dual therapy was associated with a higher frequency of initial adequate antibiotic therapy. However, no difference in 60-day mortality was found between monotherapy (β-lactam) and either of the two dual-therapy groups (β-lactam plus macrolide or fluoroquinolone). The rates of nosocomial pneumonia and multidrug-resistant bacteria were not significantly different across these three groups. Conclusions Initial adequate antibiotic therapy markedly decreased 60-day mortality. Dual therapy improved the likelihood of initial adequate therapy but did not predict decreased 60-day mortality. Dual therapy did not increase the risk of nosocomial pneumonia or multidrug-resistant bacteria. PMID:24200097

  1. Molecular modeling, dynamics studies and virtual screening of Fructose 1, 6 biphosphate aldolase-II in community acquired- methicillin resistant Staphylococcus aureus (CA-MRSA).

    PubMed

    Yadav, Pramod Kumar; Singh, Gurmit; Gautam, Budhayash; Singh, Satendra; Yadav, Madhu; Srivastav, Upasana; Singh, Brijendra

    2013-01-01

    Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) has recently emerged as a nosocomial pathogen to the community which commonly causes skin and soft-tissue infections (SSTIs). This strain (MW2) has now become resistant to the most of the beta-lactam antibiotics; therefore it is the urgent need to identify the novel drug targets. Recently fructose 1,6 biphosphate aldolase-II (FBA) has been identified as potential drug target in CA-MRSA. The FBA catalyses the retro-ketolic cleavage of fructose-1,6-bisphosphate (FBP) to yield dihydroxyacetone phosphate (DHAP) and glyceraldehyde-3-phosphate (G3P) in glycolytic pathway. In the present research work the 3D structure of FBA was predicted using the homology modeling method followed by validation. The molecular dynamics simulation (MDS) of the predicted model was carried out using the 2000 ps time scale and 1000000 steps. The MDS results suggest that the modeled structure is stable. The predicted model of FBA was used for virtual screening against the NCI diversity subset-II ligand databases which contain 1364 compounds. Based on the docking energy scores, it was found that top four ligands i.e. ZINC01690699, ZINC13154304, ZINC29590257 and ZINC29590259 were having lower energy scores which reveal higher binding affinity towards the active site of FBA. These ligands might act as potent inhibitors for the FBA so that the menace of antimicrobial resistance in CA-MRSA can be conquered. However, pharmacological studies are required to confirm the inhibitory activity of these ligands against the FBA in CA-MRSA.

  2. Tracking Cefoperazone/Sulbactam Resistance Development In vivo in A. baumannii Isolated from a Patient with Hospital-Acquired Pneumonia by Whole-Genome Sequencing

    PubMed Central

    Liu, Xiaofen; Zheng, Huajun; Zhang, Weipeng; Shen, Zhen; Zhao, Miao; Chen, Yuancheng; Sun, Li; Shi, Jun; Zhang, Jing

    2016-01-01

    Cefoperazone/sulbactam has been shown to be efficacious for the treatment of infections caused by Acinetobacter baumannii; however, the mechanism underlying resistance to this synergistic combination is not well understood. In the present study, two A. baumannii isolates, AB1845 and AB2092, were isolated from a patient with hospital-acquired pneumonia before and after 20 days of cefoperazone/sulbactam therapy (2:1, 3 g every 8 h with a 1-h infusion). The minimum inhibitory concentration (MIC) of cefoperazone/sulbactam for AB1845 and AB2092 was 16/8 and 128/64 mg/L, respectively. Blood samples were collected on day 4 of the treatment to determine the concentration of cefoperazone and sulbactam. The pharmacokinetic/pharmacodynamic (PK/PD) indices (%T>MIC) were calculated to evaluate the dosage regimen and resistance development. The results showed that %T>MIC of cefoperazone and sulbactam was 100% and 34.5% for AB1845, and 0% and 0% for AB2092, respectively. Although there was no available PK/PD target for sulbactam, it was proposed that sulbactam should be administered at higher doses or for prolonged infusion times to achieve better efficacy. To investigate the mechanism of A. baumannii resistance to the cefoperazone/sulbactam combination in vivo, whole-genome sequencing of these two isolates was further performed. The sequencing results showed that 97.6% of the genome sequences were identical and 33 non-synonymous mutations were detected between AB1845 and AB2092. The only difference of these two isolates was showed in sequencing coverage comparison. There was a 6-kb amplified DNA fragment which was three times higher in AB2092, compared with AB1845. The amplified DNA fragment containing the blaOXA-23 gene on transposon Tn2009. Further quantitative real-time PCR results demonstrated that gene expression at the mRNA level of blaOXA-23 was >5 times higher in AB2092 than in AB1845. These results suggested that the blaOXA-23 gene had higher expression level in AB2092

  3. Tracking Cefoperazone/Sulbactam Resistance Development In vivo in A. baumannii Isolated from a Patient with Hospital-Acquired Pneumonia by Whole-Genome Sequencing.

    PubMed

    Liu, Xiaofen; Zheng, Huajun; Zhang, Weipeng; Shen, Zhen; Zhao, Miao; Chen, Yuancheng; Sun, Li; Shi, Jun; Zhang, Jing

    2016-01-01

    Cefoperazone/sulbactam has been shown to be efficacious for the treatment of infections caused by Acinetobacter baumannii; however, the mechanism underlying resistance to this synergistic combination is not well understood. In the present study, two A. baumannii isolates, AB1845 and AB2092, were isolated from a patient with hospital-acquired pneumonia before and after 20 days of cefoperazone/sulbactam therapy (2:1, 3 g every 8 h with a 1-h infusion). The minimum inhibitory concentration (MIC) of cefoperazone/sulbactam for AB1845 and AB2092 was 16/8 and 128/64 mg/L, respectively. Blood samples were collected on day 4 of the treatment to determine the concentration of cefoperazone and sulbactam. The pharmacokinetic/pharmacodynamic (PK/PD) indices (%T>MIC) were calculated to evaluate the dosage regimen and resistance development. The results showed that %T>MIC of cefoperazone and sulbactam was 100% and 34.5% for AB1845, and 0% and 0% for AB2092, respectively. Although there was no available PK/PD target for sulbactam, it was proposed that sulbactam should be administered at higher doses or for prolonged infusion times to achieve better efficacy. To investigate the mechanism of A. baumannii resistance to the cefoperazone/sulbactam combination in vivo, whole-genome sequencing of these two isolates was further performed. The sequencing results showed that 97.6% of the genome sequences were identical and 33 non-synonymous mutations were detected between AB1845 and AB2092. The only difference of these two isolates was showed in sequencing coverage comparison. There was a 6-kb amplified DNA fragment which was three times higher in AB2092, compared with AB1845. The amplified DNA fragment containing the bla OXA-23 gene on transposon Tn2009. Further quantitative real-time PCR results demonstrated that gene expression at the mRNA level of bla OXA-23 was >5 times higher in AB2092 than in AB1845. These results suggested that the bla OXA-23 gene had higher expression level in AB

  4. Tracking Cefoperazone/Sulbactam Resistance Development In vivo in A. baumannii Isolated from a Patient with Hospital-Acquired Pneumonia by Whole-Genome Sequencing

    PubMed Central

    Liu, Xiaofen; Zheng, Huajun; Zhang, Weipeng; Shen, Zhen; Zhao, Miao; Chen, Yuancheng; Sun, Li; Shi, Jun; Zhang, Jing

    2016-01-01

    Cefoperazone/sulbactam has been shown to be efficacious for the treatment of infections caused by Acinetobacter baumannii; however, the mechanism underlying resistance to this synergistic combination is not well understood. In the present study, two A. baumannii isolates, AB1845 and AB2092, were isolated from a patient with hospital-acquired pneumonia before and after 20 days of cefoperazone/sulbactam therapy (2:1, 3 g every 8 h with a 1-h infusion). The minimum inhibitory concentration (MIC) of cefoperazone/sulbactam for AB1845 and AB2092 was 16/8 and 128/64 mg/L, respectively. Blood samples were collected on day 4 of the treatment to determine the concentration of cefoperazone and sulbactam. The pharmacokinetic/pharmacodynamic (PK/PD) indices (%T>MIC) were calculated to evaluate the dosage regimen and resistance development. The results showed that %T>MIC of cefoperazone and sulbactam was 100% and 34.5% for AB1845, and 0% and 0% for AB2092, respectively. Although there was no available PK/PD target for sulbactam, it was proposed that sulbactam should be administered at higher doses or for prolonged infusion times to achieve better efficacy. To investigate the mechanism of A. baumannii resistance to the cefoperazone/sulbactam combination in vivo, whole-genome sequencing of these two isolates was further performed. The sequencing results showed that 97.6% of the genome sequences were identical and 33 non-synonymous mutations were detected between AB1845 and AB2092. The only difference of these two isolates was showed in sequencing coverage comparison. There was a 6-kb amplified DNA fragment which was three times higher in AB2092, compared with AB1845. The amplified DNA fragment containing the blaOXA-23 gene on transposon Tn2009. Further quantitative real-time PCR results demonstrated that gene expression at the mRNA level of blaOXA-23 was >5 times higher in AB2092 than in AB1845. These results suggested that the blaOXA-23 gene had higher expression level in AB2092

  5. Travel to Asia and traveller's diarrhoea with antibiotic treatment are independent risk factors for acquiring ciprofloxacin-resistant and extended spectrum β-lactamase-producing Enterobacteriaceae-a prospective cohort study.

    PubMed

    Reuland, E A; Sonder, G J B; Stolte, I; Al Naiemi, N; Koek, A; Linde, G B; van de Laar, T J W; Vandenbroucke-Grauls, C M J E; van Dam, A P

    2016-08-01

    Travel to (sub)tropical countries is a well-known risk factor for acquiring resistant bacterial strains, which is especially of significance for travellers from countries with low resistance rates. In this study we investigated the rate of and risk factors for travel-related acquisition of extended spectrum β-lactamase-producing Enterobacteriaceae (ESBL-E), ciprofloxacin-resistant Enterobacteriaceae (CIPR-E) and carbapenem-resistant Enterobacteriaceae. Data before and after travel were collected from 445 participants. Swabs were cultured with an enrichment broth and sub-cultured on selective agar plates for ESBL detection, and on plates with a ciprofloxacin disc. ESBL production was confirmed with the double-disc synergy test. Species identification and susceptibility testing were performed with the Vitek-2 system. All isolates were subjected to ertapenem Etest. ESBL and carbapenemase genes were characterized by PCR and sequencing. Twenty-seven out of 445 travellers (6.1%) already had ESBL-producing strains and 45 of 445 (10.1%) travellers had strains resistant to ciprofloxacin before travel. Ninety-eight out of 418 (23.4%) travellers acquired ESBL-E and 130 of 400 (32.5%) travellers acquired a ciprofloxacin-resistant strain. Of the 98 ESBL-E, predominantly Escherichia coli and predominantly blaCTX-M-15, 56% (55/98) were resistant to gentamicin, ciprofloxacin and co-trimoxazole. Multivariate analysis showed that Asia was a high-risk area for ESBL-E as well as CIPR-E acquisition. Travellers with diarrhoea combined with antimicrobial use were significantly at higher risk for acquisition of resistant strains. Only one carbapenemase-producing isolate was acquired, isolated from a participant after visiting Egypt. In conclusion, travelling to Asia and diarrhoea combined with antimicrobial use are important risk factors for acquiring ESBL-E and CIPR-E. PMID:27223840

  6. Integrin β1-mediated acquired gefitinib resistance in non-small cell lung cancer cells occurs via the phosphoinositide 3-kinase-dependent pathway

    PubMed Central

    DENG, QIN-FANG; SU, BO; ZHAO, YIN-MIN; TANG, LIANG; ZHANG, JIE; ZHOU, CAI-CUN

    2016-01-01

    The present study aimed to explore the role of integrin β1 and the relevant signaling pathways in acquired gefitinib resistance in non-small cell lung cancer (NSCLC). The inhibitory effects of gefitinib, with or without LY294002, on cellular proliferation were evaluated by 3-(4,5-dimethylthiazol-2-yl) 2,5-diphenyltetrazolium bromide assay. Cell cycle progression and apoptosis were analyzed by flow cytometry, while western blotting was used to evaluate the expression of EGFR, phosphorylated (phospho)-EGFR, protein kinase B (Akt), phospho-Akt, extracellular signal-regulated kinase (Erk) and phospho-Erk. The gene expression profiles of PC9 and PC9/G cells were determined by DNA microarray. Integrin β1 was knocked down in PC9/G cells by transiently transfected short interfering RNA (siRNA). A scrambled siRNA sequence was used as a control. Apoptosis of transfected cells was determined by Annexin V-phycoerythrin-Cy5/propidium iodide staining. Sequencing products were amplified by nested PCR. The resistant index of PC9/G cells to gefitinib was ~138- to 256-fold higher than that of PC9 cells, and this resistance was accompanied by significant increase in integrin β1 expression in PC9/G cells. Knockdown of integrin β1 with short hairpin RNA in PC9/G cells markedly inhibited proliferation and enhanced apoptosis in response to gefitinib, restoring the sensitivity of PC9/G cells gefitinib. Phosphoinositide 3-kinase (PI3K)/Akt activation was observed in PC9/G cells in the presence of gefitinib and the sensitivity of PC9/G cells to gefitinib was also able to be restored by PI3K/Akt pathway inhibitor LY294002. Finally, knockdown of integrin β1 significantly reduced the levels of phospho-Akt. These findings suggest that integrin β1 signaling via the PI3K/Akt pathway may be a significant mechanism underlying gefitinib resistance, and may potentially present an alternative therapeutic target for the treatment of NSCLC unresponsive to EGFR inhibitors. PMID:26870244

  7. Atypical Cell Populations Associated with Acquired Resistance to Cytostatics and Cancer Stem Cell Features: The Role of Mitochondria in Nuclear Encapsulation

    PubMed Central

    Gustmann, Sebastian; Jastrow, Holger; Acikelli, Ali Haydar; Dammann, Philip; Klein, Jacqueline; Dembinski, Ulrike; Bardenheuer, Walter; Malak, Sascha; Araúzo-Bravo, Marcos J.; Schultheis, Beate; Aldinger, Constanze; Strumberg, Dirk

    2014-01-01

    Until recently, acquired resistance to cytostatics had mostly been attributed to biochemical mechanisms such as decreased intake and/or increased efflux of therapeutics, enhanced DNA repair, and altered activity or deregulation of target proteins. Although these mechanisms have been widely investigated, little is known about membrane barriers responsible for the chemical imperviousness of cell compartments and cellular segregation in cytostatic-treated tumors. In highly heterogeneous cross-resistant and radiorefractory cell populations selected by exposure to anticancer agents, we found a number of atypical recurrent cell types in (1) tumor cell cultures of different embryonic origins, (2) mouse xenografts, and (3) paraffin sections from patient tumors. Alongside morphologic peculiarities, these populations presented cancer stem cell markers, aberrant signaling pathways, and a set of deregulated miRNAs known to confer both stem-cell phenotypes and highly aggressive tumor behavior. The first type, named spiral cells, is marked by a spiral arrangement of nuclei. The second type, monastery cells, is characterized by prominent walls inside which daughter cells can be seen maturing amid a rich mitochondrial environment. The third type, called pregnant cells, is a giant cell with a syncytium-like morphology, a main nucleus, and many endoreplicative functional progeny cells. A rare fourth cell type identified in leukemia was christened shepherd cells, as it was always associated with clusters of smaller cells. Furthermore, a portion of resistant tumor cells displayed nuclear encapsulation via mitochondrial aggregation in the nuclear perimeter in response to cytostatic insults, probably conferring imperviousness to drugs and long periods of dormancy until nuclear eclosion takes place. This phenomenon was correlated with an increase in both intracellular and intercellular mitochondrial traffic as well as with the uptake of free extracellular mitochondria. All these cellular

  8. Dose-Dependent Mutation Rates Determine Optimum Erlotinib Dosing Strategies for EGFR Mutant Non-Small Cell Lung Cancer Patients

    PubMed Central

    Liu, Lin L.; Li, Fei; Pao, William; Michor, Franziska

    2015-01-01

    Background The advent of targeted therapy for cancer treatment has brought about a paradigm shift in the clinical management of human malignancies. Agents such as erlotinib used for EGFR-mutant non-small cell lung cancer or imatinib for chronic myeloid leukemia, for instance, lead to rapid tumor responses. Unfortunately, however, resistance often emerges and renders these agents ineffective after a variable amount of time. The FDA-approved dosing schedules for these drugs were not designed to optimally prevent the emergence of resistance. To this end, we have previously utilized evolutionary mathematical modeling of treatment responses to elucidate the dosing schedules best able to prevent or delay the onset of resistance. Here we expand on our approaches by taking into account dose-dependent mutation rates at which resistant cells emerge. The relationship between the serum drug concentration and the rate at which resistance mutations arise can lead to non-intuitive results about the best dose administration strategies to prevent or delay the emergence of resistance. Methods We used mathematical modeling, available clinical trial data, and different considerations of the relationship between mutation rate and drug concentration to predict the effectiveness of different dosing strategies. Results We designed several distinct measures to interrogate the effects of different treatment dosing strategies and found that a low-dose continuous strategy coupled with high-dose pulses leads to the maximal delay until clinically observable resistance. Furthermore, the response to treatment is robust against different assumptions of the mutation rate as a function of drug concentration. Conclusions For new and existing targeted drugs, our methodology can be employed to compare the effectiveness of different dose administration schedules and investigate the influence of changing mutation rates on outcomes. PMID:26536620

  9. Bilberry extract, its major polyphenolic compounds, and the soy isoflavone genistein antagonize the cytostatic drug erlotinib in human epithelial cells.

    PubMed

    Aichinger, G; Pahlke, G; Nagel, L J; Berger, W; Marko, D

    2016-08-10

    Erlotinib (Tarceva®) is a chemotherapeutic drug approved for the treatment of pancreatic cancer and non-small cell lung cancer. Its primary mode of action is the inhibition of the epidermal growth factor receptor (EGFR), a receptor tyrosine kinase (RTK). Recently, RTK-inhibiting polyphenols have been reported to interact synergistically with erlotinib. Furthermore some anthocyanidins and anthocyanin-rich berry extracts have been reported to inhibit tyrosine kinases, including the EGFR, which raises the question of potential interactions with erlotinib. Polyphenol-rich preparations such as berry- or soy-based products are commercially available as food supplements. In the present study we tested a bilberry extract, its major anthocyanin and potential intestinal degradation products, as well as genistein, with respect to possible interactions with erlotinib. Cell growth inhibition was assessed using the sulforhodamine B assay, while interactions with EGFR phosphorylation were analyzed by SDS-PAGE/western blotting with subsequent immunodetection. Genistein, bilberry extract, delphinidin-3-O-glucoside and delphinidin were found to antagonize erlotinib whereas phloroglucinol aldehyde was found to enhance cytostatic effects of the drug on human epithelial A431 cells. Genistein also antagonized the EGFR inhibitory effects of erlotinib, whereas bilberry anthocyanins showed no significant interactions in this regard. Our data indicate that different polyphenols are potentially able to impair the cytostatic effect of erlotinib in vitro. Genistein interacts via the modulation of erlotinib-mediated EGFR inhibition whereas bilberry anthocyanins modulated the growth-inhibitory effect of erlotinib without affecting EGFR phosphorylation, thus indicating a different mechanism of interference. PMID:27485636

  10. Orthology Analysis and In Vivo Complementation Studies to Elucidate the Role of DIR1 during Systemic Acquired Resistance in Arabidopsis thaliana and Cucumis sativus

    PubMed Central

    Isaacs, Marisa; Carella, Philip; Faubert, Jennifer; Rose, Jocelyn K. C.; Cameron, Robin K.

    2016-01-01

    AtDIR1 (Defective in Induced Resistance1) is an acidic lipid transfer protein essential for systemic acquired resistance (SAR) in Arabidopsis thaliana. Upon SAR induction, DIR1 moves from locally infected to distant uninfected leaves to activate defense priming; however, a molecular function for DIR1 has not been elucidated. Bioinformatic analysis and in silico homology modeling identified putative AtDIR1 orthologs in crop species, revealing conserved protein motifs within and outside of DIR1’s central hydrophobic cavity. In vitro assays to compare the capacity of recombinant AtDIR1 and targeted AtDIR1-variant proteins to bind the lipophilic probe TNS (6,P-toluidinylnaphthalene-2-sulfonate) provided evidence that conserved leucine 43 and aspartic acid 39 contribute to the size of the DIR1 hydrophobic cavity and possibly hydrophobic ligand binding. An Arabidopsis–cucumber SAR model was developed to investigate the conservation of DIR1 function in cucumber (Cucumis sativus), and we demonstrated that phloem exudates from SAR-induced cucumber rescued the SAR defect in the Arabidopsis dir1-1 mutant. Additionally, an AtDIR1 antibody detected a protein of the same size as AtDIR1 in SAR-induced cucumber phloem exudates, providing evidence that DIR1 function during SAR is conserved in Arabidopsis and cucumber. In vitro TNS displacement assays demonstrated that recombinant AtDIR1 did not bind the SAR signals azelaic acid (AzA), glycerol-3-phosphate or pipecolic acid. However, recombinant CsDIR1 and CsDIR2 interacted weakly with AzA and pipecolic acid. Bioinformatic and functional analyses using the Arabidopsis–cucumber SAR model provide evidence that DIR1 orthologs exist in tobacco, tomato, cucumber, and soybean, and that DIR1-mediated SAR signaling is conserved in Arabidopsis and cucumber. PMID:27200039

  11. Orthology Analysis and In Vivo Complementation Studies to Elucidate the Role of DIR1 during Systemic Acquired Resistance in Arabidopsis thaliana and Cucumis sativus.

    PubMed

    Isaacs, Marisa; Carella, Philip; Faubert, Jennifer; Rose, Jocelyn K C; Cameron, Robin K

    2016-01-01

    AtDIR1 (Defective in Induced Resistance1) is an acidic lipid transfer protein essential for systemic acquired resistance (SAR) in Arabidopsis thaliana. Upon SAR induction, DIR1 moves from locally infected to distant uninfected leaves to activate defense priming; however, a molecular function for DIR1 has not been elucidated. Bioinformatic analysis and in silico homology modeling identified putative AtDIR1 orthologs in crop species, revealing conserved protein motifs within and outside of DIR1's central hydrophobic cavity. In vitro assays to compare the capacity of recombinant AtDIR1 and targeted AtDIR1-variant proteins to bind the lipophilic probe TNS (6,P-toluidinylnaphthalene-2-sulfonate) provided evidence that conserved leucine 43 and aspartic acid 39 contribute to the size of the DIR1 hydrophobic cavity and possibly hydrophobic ligand binding. An Arabidopsis-cucumber SAR model was developed to investigate the conservation of DIR1 function in cucumber (Cucumis sativus), and we demonstrated that phloem exudates from SAR-induced cucumber rescued the SAR defect in the Arabidopsis dir1-1 mutant. Additionally, an AtDIR1 antibody detected a protein of the same size as AtDIR1 in SAR-induced cucumber phloem exudates, providing evidence that DIR1 function during SAR is conserved in Arabidopsis and cucumber. In vitro TNS displacement assays demonstrated that recombinant AtDIR1 did not bind the SAR signals azelaic acid (AzA), glycerol-3-phosphate or pipecolic acid. However, recombinant CsDIR1 and CsDIR2 interacted weakly with AzA and pipecolic acid. Bioinformatic and functional analyses using the Arabidopsis-cucumber SAR model provide evidence that DIR1 orthologs exist in tobacco, tomato, cucumber, and soybean, and that DIR1-mediated SAR signaling is conserved in Arabidopsis and cucumber.

  12. Orthology Analysis and In Vivo Complementation Studies to Elucidate the Role of DIR1 during Systemic Acquired Resistance in Arabidopsis thaliana and Cucumis sativus.

    PubMed

    Isaacs, Marisa; Carella, Philip; Faubert, Jennifer; Rose, Jocelyn K C; Cameron, Robin K

    2016-01-01

    AtDIR1 (Defective in Induced Resistance1) is an acidic lipid transfer protein essential for systemic acquired resistance (SAR) in Arabidopsis thaliana. Upon SAR induction, DIR1 moves from locally infected to distant uninfected leaves to activate defense priming; however, a molecular function for DIR1 has not been elucidated. Bioinformatic analysis and in silico homology modeling identified putative AtDIR1 orthologs in crop species, revealing conserved protein motifs within and outside of DIR1's central hydrophobic cavity. In vitro assays to compare the capacity of recombinant AtDIR1 and targeted AtDIR1-variant proteins to bind the lipophilic probe TNS (6,P-toluidinylnaphthalene-2-sulfonate) provided evidence that conserved leucine 43 and aspartic acid 39 contribute to the size of the DIR1 hydrophobic cavity and possibly hydrophobic ligand binding. An Arabidopsis-cucumber SAR model was developed to investigate the conservation of DIR1 function in cucumber (Cucumis sativus), and we demonstrated that phloem exudates from SAR-induced cucumber rescued the SAR defect in the Arabidopsis dir1-1 mutant. Additionally, an AtDIR1 antibody detected a protein of the same size as AtDIR1 in SAR-induced cucumber phloem exudates, providing evidence that DIR1 function during SAR is conserved in Arabidopsis and cucumber. In vitro TNS displacement assays demonstrated that recombinant AtDIR1 did not bind the SAR signals azelaic acid (AzA), glycerol-3-phosphate or pipecolic acid. However, recombinant CsDIR1 and CsDIR2 interacted weakly with AzA and pipecolic acid. Bioinformatic and functional analyses using the Arabidopsis-cucumber SAR model provide evidence that DIR1 orthologs exist in tobacco, tomato, cucumber, and soybean, and that DIR1-mediated SAR signaling is conserved in Arabidopsis and cucumber. PMID:27200039

  13. A comparison of virulence patterns and in vivo fitness between hospital- and community-acquired methicillin-resistant Staphylococcus aureus related to the USA400 clone.

    PubMed

    Guimarães, M A; Ramundo, M S; Américo, M A; de Mattos, M C; Souza, R R; Ramos-Júnior, E S; Coelho, L R; Morrot, A; Melo, P A; Fracalanzza, S E L; Ferreira, F A; Figueiredo, A M S

    2015-03-01

    Methicillin-resistant Staphylococcus aureus (MRSA) isolates genetically related to the CA-MRSA clone MW2/USA400 (ST1-SCCmecIV lineage) from the United States have emerged in hospitals in Rio de Janeiro and are associated with nosocomial bloodstream infections. To understand the virulence mechanisms involved in the adaptability of ST1 isolates as a hospital pathogen in Rio de Janeiro, we compared the virulence traits and fitness properties of the Brazilian isolates with those displayed by the CA-MRSA isolates from the United States. Similar to the USA400 from the United States, all the Brazilian isolates tested carried the genes encoding SEH and LukDE. In contrast, none of the Brazilian isolates carried the lukSF PVL, sea, sec, and sek genes. Competition experiments in mice demonstrated a significant increase in the fitness for the CA-MRSA isolates MW2 and USA400-0051 from the United States compared to other isolates. In the foreign body animal model, 83 % more North-American bacterial cells were recovered compared to the Brazilian ST1 isolates. Differences in gene expression of important virulence factors were detected. Transcription of rnaIII and psmα3 was increased about two-fold in the isolates from the United States, and sasG about two-fold in the Brazilian isolates. Thus, it is possible that the virulence attenuation observed among the Brazilian hospital isolates, associated with the acquisition of multiple resistant determinants, are consequences of microevolutionary events that contributed to the necessary fitness adjustment of this lineage, allowing a typically community-acquired MRSA (MW2/USA400) to emerge as a successful hospital pathogen (Brazilian ST1-SCCmecIV).

  14. Rapid radiosynthesis of [11C] and [14C]azelaic, suberic, and sebacic acids for in vivo mechanistic studies of systemic acquired resistance in plants

    SciTech Connect

    Best M.; Fowler J.; Best, M.; Gifford, A.N.; Kim, S.W.; Babst, B.; Piel, M.; Roesch, F.; Fowler, J.S.

    2011-11-25

    A recent report that the aliphatic dicarboxylic acid, azelaic acid (1,9-nonanedioic acid) but not related acids, suberic acid (1,8-octanedioic acid) or sebacic (1,10-decanedioic acid) acid induces systemic acquired resistance to invading pathogens in plants stimulated the development of a rapid method for labeling these dicarboxylic acids with {sup 11}C and {sup 14}C for in vivo mechanistic studies in whole plants. {sup 11}C-labeling was performed by reaction of ammonium [{sup 11}C]cyanide with the corresponding bromonitrile precursor followed by hydrolysis with aqueous sodium hydroxide solution. Total synthesis time was 60 min. Median decay-corrected radiochemical yield for [{sup 11}C]azelaic acid was 40% relative to trapped [{sup 11}C]cyanide, and specific activity was 15 GBq/{micro}mol. Yields for [{sup 11}C]suberic and sebacic acids were similar. The {sup 14}C-labeled version of azelaic acid was prepared from potassium [{sup 14}C]cyanide in 45% overall radiochemical yield. Radiolabeling procedures were verified using {sup 13}C-labeling coupled with {sup 13}C-NMR and liquid chromatography-mass spectrometry analysis. The {sup 11}C and {sup 14}C-labeled azelaic acid and related dicarboxylic acids are expected to be of value in understanding the mode-of-action, transport, and fate of this putative signaling molecule in plants.

  15. Salicylic Acid and Systemic Acquired Resistance Play a Role in Attenuating Crown Gall Disease Caused by Agrobacterium tumefaciens1[W][OA

    PubMed Central

    Anand, Ajith; Uppalapati, Srinivasa Rao; Ryu, Choong-Min; Allen, Stacy N.; Kang, Li; Tang, Yuhong; Mysore, Kirankumar S.

    2008-01-01

    We investigated the effects of salicylic acid (SA) and systemic acquired resistance (SAR) on crown gall disease caused by Agrobacterium tumefaciens. Nicotiana benthamiana plants treated with SA showed decreased susceptibility to Agrobacterium infection. Exogenous application of SA to Agrobacterium cultures decreased its growth, virulence, and attachment to plant cells. Using Agrobacterium whole-genome microarrays, we characterized the direct effects of SA on bacterial gene expression and showed that SA inhibits induction of virulence (vir) genes and the repABC operon, and differentially regulates the expression of many other sets of genes. Using virus-induced gene silencing, we further demonstrate that plant genes involved in SA biosynthesis and signaling are important determinants for Agrobacterium infectivity on plants. Silencing of ICS (isochorismate synthase), NPR1 (nonexpresser of pathogenesis-related gene 1), and SABP2 (SA-binding protein 2) in N. benthamiana enhanced Agrobacterium infection. Moreover, plants treated with benzo-(1,2,3)-thiadiazole-7-carbothioic acid, a potent inducer of SAR, showed reduced disease symptoms. Our data suggest that SA and SAR both play a major role in retarding Agrobacterium infectivity. PMID:18156296

  16. Combined Targeting of JAK2 and Bcl-2/Bcl-xL to Cure Mutant JAK2-Driven Malignancies and Overcome Acquired Resistance to JAK2 Inhibitors

    PubMed Central

    Waibel, Michaela; Solomon, Vanessa S.; Knight, Deborah A.; Ralli, Rachael A.; Kim, Sang-Kyu; Banks, Kellie-Marie; Vidacs, Eva; Virely, Clemence; Sia, Keith C.S.; Bracken, Lauryn S.; Collins-Underwood, Racquel; Drenberg, Christina; Ramsey, Laura B.; Meyer, Sara C.; Takiguchi, Megumi; Dickins, Ross A.; Levine, Ross; Ghysdael, Jacques; Dawson, Mark A.; Lock, Richard B.; Mullighan, Charles G.; Johnstone, Ricky W.

    2013-01-01

    Summary To design rational therapies for JAK2-driven hematological malignancies, we functionally dissected the key survival pathways downstream of hyperactive JAK2. In tumors driven by mutant JAK2, Stat1, Stat3, Stat5, and the Pi3k and Mek/Erk pathways were constitutively active, and gene expression profiling of TEL-JAK2 T-ALL cells revealed the upregulation of prosurvival Bcl-2 family genes. Combining the Bcl-2/Bcl-xL inhibitor ABT-737 with JAK2 inhibitors mediated prolonged disease regressions and cures in mice bearing primary human and mouse JAK2 mutant tumors. Moreover, combined targeting of JAK2 and Bcl-2/Bcl-xL was able to circumvent and overcome acquired resistance to single-agent JAK2 inhibitor treatment. Thus, inhibiting the oncogenic JAK2 signaling network at two nodal points, at the initiating stage (JAK2) and the effector stage (Bcl-2/Bcl-xL), is highly effective and provides a clearly superior therapeutic benefit than targeting just one node. Therefore, we have defined a potentially curative treatment for hematological malignancies expressing constitutively active JAK2. PMID:24268771

  17. Mutational analysis of the Verticillium dahliae protein elicitor PevD1 identifies distinctive regions responsible for hypersensitive response and systemic acquired resistance in tobacco.

    PubMed

    Liu, Wenxian; Zeng, Hongmei; Liu, Zhipeng; Yang, Xiufen; Guo, Lihua; Qiu, Dewen

    2014-01-01

    In our previous study, PevD1 was characterized as a novel protein elicitor produced by Verticillium dahliae inducing hypersensitive response (HR) and systemic acquired resistance (SAR) in tobacco plants; however, the detailed mechanisms of PevD1's elicitor activity remain unclear. In this study, five mutant fragments of PevD1 were generated by polymerase chain reaction-based mutagenesis and the truncated proteins expressed in Escherichia coli were used to test their elicitor activities. Biological activity analysis showed that the N-terminal and C-terminal of PevD1 had distinct influence on HR and SAR elicitation. Fragment PevD1ΔN98, which spans the C-terminal 57 amino acids of PevD1, was critical for the induction of HR in tobacco plants. In contrast, fragment PevD1ΔC57, the N-terminal of 98 amino acids of PevD1, retained the ability to induce SAR against tobacco mosaic virus (TMV) but not induction of HR, suggesting that the induction of HR is not essential for SAR mediated by PevD1. Our results indicated that fragment PevD1ΔC57 could be a candidate peptide for plant protection against pathogens without causing negative effects.

  18. The first report in Brazil of severe infection caused by community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA).

    PubMed

    Rozenbaum, R; Sampaio, M G; Batista, G S; Garibaldi, A M; Terra, G M F; Souza, M J; Vieira, E N; Silva-Carvalho, M C; Teixeira, L A; Figueiredo, A M S

    2009-08-01

    Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) is an emergent pathogen in Brazil. However, there are no data on the prevalence of CA-MRSA. We report here the first well-characterized case of severe life-threatening CA-MRSA infection in a child living in Rio de Janeiro city. The patient had many complications including hematogenous osteomyelitis and involvement of multiple sites requiring drainage of soft-tissue abscess, and pleural and pericardial empyema. The MRSA isolates recovered were genotyped using PFGE, SCCmec typing and multilocus sequence typing. Disk diffusion tests were performed following Clinical and Laboratory Standards Institute recommendations. In addition, the presence of Panton-Valentine leukocidin (PVL) was assessed by PCR amplification, using specific primers for lukF-pv (encoding for the F subunit of the PVL). The bacterial isolates were related to the ST30-SCCmecIV lineage (Oceania Southwest Pacific clone), a PVL producer CA-MRSA previously detected in Porto Alegre, RS, Brazil. Also, the isolates analyzed were susceptible to all non-beta-lactam antibiotics tested. The present report demonstrates that disseminated CA-MRSA disease is also occurring in Rio de Janeiro. Thus, the empirical treatment of moderate or severe infections suspected of being associated with CA-MRSA needs to be reviewed in order to allow prompt initiation of an effective therapy that also covers these microorganisms.

  19. Activation of the IGF1R pathway potentially mediates acquired resistance to mutant-selective 3rd-generation EGF receptor tyrosine kinase inhibitors in advanced non-small cell lung cancer

    PubMed Central

    Park, Ji Hyun; Choi, Yun Jung; Kim, Seon Ye; Lee, Jung-Eun; Sung, Ki Jung; Park, Sojung; Kim, Woo Sung; Song, Joon Seon; Choi, Chang-Min; Sung, Young Hoon; Rho, Jin Kyung; Lee, Jae Cheol

    2016-01-01

    Mutant-selective, 3rd-generation EGFR-TKIs were recently developed to control lung cancer cells harboring T790M-mediated resistance. However, the development of resistance to these novel drugs seems inevitable. Thus, we investigated the mechanism of acquired resistance to the mutant-selective EGFR-TKI WZ4002. We established five WZ4002-resistant cells, derived from cells harboring both EGFR and T790M mutations by long-term exposure to increasing doses of WZ4002. Compared with the parental cells, all resistant cells showed 10–100-folds higher resistance to WZ4002, as well as cross-resistance to other mutant-selective inhibitors. Among them, three resistant cells (HCC827/WR, PC-9/WR and H1975/WR) showed dependency on EGFR signaling, but two other cells (PC-9/GR/WR and PC-9/ER/WR) were not. Notably, insulin-like growth factor-1 receptor (IGF1R) was aberrantly activated in PC-9/GR/WR cells in phospho-receptor tyrosine kinase array, consistently accompanied by loss of IGF binding protein-3 (IGFBP3). Down-regulation of IGF1R by shRNA, as well as inhibition of IGF1R activity either by AG-1024 (a small molecule IGF1R inhibitor) or BI 836845 (a monoclonal anti-IGF1/2 blocking antibody), restored the sensitivity to WZ4002 both in vitro and xenograft. Taken together, these results suggest that activation of the IGF1R pathway associated with IGFBP3 loss can induce an acquired resistance to the mutant-selective EGFR-TKI, WZ4002. Therefore, a combined therapy of IGF1R inhibitors and mutant-selective EGFR-TKIs might be a viable treatment strategy for overcoming acquired resistance. PMID:26980747

  20. Erlotinib versus carboplatin and paclitaxel in advanced lepidic adenocarcinoma: IFCT-0504.

    PubMed

    Cadranel, Jacques; Gervais, Radj; Merle, Patrick; Moro-Sibilot, Denis; Westeel, Virginie; Bigay-Game, Laurence; Quoix, Elisabeth; Friard, Sylvie; Barlesi, Fabrice; Lethrosne, Claire; Moreau, Lionel; Monnet, Isabelle; Salaun, Mathieu; Oliviero, Gérard; Souquet, Pierre-Jean; Antoine, Martine; Langlais, Alexandra; Morin, Franck; Wislez, Marie; Zalcman, Gérard

    2015-11-01

    The IFCT-0504 phase II trial evaluated the efficacy of erlotinib versus carboplatin-paclitaxel (CP) as first-line treatment in 130 cases of advanced lepidic-predominant adenocarcinoma (ADC).The primary objective of the study was treatment efficacy, evaluated based on an end-point of disease control at 16 weeks.The primary objective was met, with a disease control in 35 (53%) out of 66 patients treated with CP and in 25 (39.1%) out of 64 patients treated with erlotinib. Median progression-free survival (PFS) for the total population was 3.6 months. The disease control rate did not differ between either the therapeutic arms or pathological subtypes, whereas there was a strong interaction between treatment arms and tumour pathological subtypes for PFS (p=0.009). Mucinous tumour patients treated with erlotinib exhibited an increased progression risk (hazard ratio 3.4, 95% CI 1.7-6.5; p≤0.001). The PFS for nonmucinous tumour patients was similar in both arms. Median overall survival was 20.1 months and did not differ between therapeutic arms. These findings were not further elucidated by molecular analyses and the toxicity profiles were as expected.Our study demonstrated the dominant role of CP alongside erlotinib in the management of advanced lepidic ADC. Based on these findings, erlotinib should not be administered in first-line therapy to patients with lepidic ADC in the absence of an epidermal growth factor receptor mutation.

  1. Gene Mutation Analysis in EGFR Wild Type NSCLC Responsive to Erlotinib: Are There Features to Guide Patient Selection?

    PubMed Central

    Ulivi, Paola; Delmonte, Angelo; Chiadini, Elisa; Calistri, Daniele; Papi, Maximilian; Mariotti, Marita; Verlicchi, Alberto; Ragazzini, Angela; Capelli, Laura; Gamboni, Alessandro; Puccetti, Maurizio; Dubini, Alessandra; Burgio, Marco Angelo; Casanova, Claudia; Crinò, Lucio; Amadori, Dino; Dazzi, Claudio

    2014-01-01

    Tyrosine kinase inhibitors (TKIs) are very efficacious in non-small-cell lung cancer (NSCLC) patients harboring activating Epidermal Growth Factor Receptor (EGFR) mutations. However, about 10% of EGFR wild type (wt) patients respond to TKI, with unknown molecular mechanisms of sensitivity. We considered a case series of 34 EGFR wt NSCLC patients responsive to erlotinib after at least one line of therapy. Responsive patients were matched with an equal number of non-responsive EGFR wt patients. A panel of 26 genes, for a total of 214 somatic mutations, was analyzed by MassARRAY® System (Sequenom, San Diego, CA, USA). A 15% KRAS mutation was observed in both groups, with a prevalence of G12C in non-responders (80% vs. 40% in responders). NOTCH1, p53 and EGFR-resistance-related mutations were found more frequently in non-responders, whereas EGFR-sensitizing mutations and alterations in genes involved in proliferation pathways were more frequent in responders. In conclusion, our findings indicate that p53, NOTCH1 and exon 20 EGFR mutations seem to be related to TKI resistance. KRAS mutations do not appear to influence the TKI response, although G12C mutation is more frequent in non-responders. Finally, the use of highly sensitive methodologies could lead to the identification of under-represented EGFR mutations potentially associated with TKI sensitivity. PMID:25561229

  2. Trichomegaly and scalp hair changes following treatment with erlotinib in pulmonary adenocarcinoma patients: A case report and literature review

    PubMed Central

    Zheng, Hua; Zhang, Hongmei; Zhang, Tongmei; Wang, Qunhui; Hu, Fanbin; Li, Baolan

    2016-01-01

    Erlotinib is among the oral EGFR-tyrosine kinase inhibitors used to treat non-small cell lung cancer. The common side effects of erlotinib include acne form rash and diarrhea. Eyelash trichomegaly and alterations of scalp hair are rarely observed symptoms. In the present study, we report changes in eyelash trichomegaly and scalp hair in six cases of pulmonary adenocarcinoma patients that had been administered erlotinib. The symptoms of eyelash trichomegaly include curly, irregular, excessively long and brittle eyelashes, and alterations of scalp hair include curly or straight, brittle, fine or rigid, reduced growth rate and volume. Since these side effects does not substantially impact patient quality of life, no treatments were administered. These changes in eyelashes and scalp hair gradually disappeared after withdrawal of erlotinib. PMID:27588051

  3. In vivo bioluminescence imaging to evaluate systemic and topical antibiotics against community-acquired methicillin-resistant Staphylococcus aureus-infected skin wounds in mice.

    PubMed

    Guo, Yi; Ramos, Romela Irene; Cho, John S; Donegan, Niles P; Cheung, Ambrose L; Miller, Lloyd S

    2013-02-01

    Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) frequently causes skin and soft tissue infections, including impetigo, cellulitis, folliculitis, and infected wounds and ulcers. Uncomplicated CA-MRSA skin infections are typically managed in an outpatient setting with oral and topical antibiotics and/or incision and drainage, whereas complicated skin infections often require hospitalization, intravenous antibiotics, and sometimes surgery. The aim of this study was to develop a mouse model of CA-MRSA wound infection to compare the efficacy of commonly used systemic and topical antibiotics. A bioluminescent USA300 CA-MRSA strain was inoculated into full-thickness scalpel wounds on the backs of mice and digital photography/image analysis and in vivo bioluminescence imaging were used to measure wound healing and the bacterial burden. Subcutaneous vancomycin, daptomycin, and linezolid similarly reduced the lesion sizes and bacterial burden. Oral linezolid, clindamycin, and doxycycline all decreased the lesion sizes and bacterial burden. Oral trimethoprim-sulfamethoxazole decreased the bacterial burden but did not decrease the lesion size. Topical mupirocin and retapamulin ointments both reduced the bacterial burden. However, the petrolatum vehicle ointment for retapamulin, but not the polyethylene glycol vehicle ointment for mupirocin, promoted wound healing and initially increased the bacterial burden. Finally, in type 2 diabetic mice, subcutaneous linezolid and daptomycin had the most rapid therapeutic effect compared with vancomycin. Taken together, this mouse model of CA-MRSA wound infection, which utilizes in vivo bioluminescence imaging to monitor the bacterial burden, represents an alternative method to evaluate the preclinical in vivo efficacy of systemic and topical antimicrobial agents.

  4. In vivo bioluminescence imaging to evaluate systemic and topical antibiotics against community-acquired methicillin-resistant Staphylococcus aureus-infected skin wounds in mice.

    PubMed

    Guo, Yi; Ramos, Romela Irene; Cho, John S; Donegan, Niles P; Cheung, Ambrose L; Miller, Lloyd S

    2013-02-01

    Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) frequently causes skin and soft tissue infections, including impetigo, cellulitis, folliculitis, and infected wounds and ulcers. Uncomplicated CA-MRSA skin infections are typically managed in an outpatient setting with oral and topical antibiotics and/or incision and drainage, whereas complicated skin infections often require hospitalization, intravenous antibiotics, and sometimes surgery. The aim of this study was to develop a mouse model of CA-MRSA wound infection to compare the efficacy of commonly used systemic and topical antibiotics. A bioluminescent USA300 CA-MRSA strain was inoculated into full-thickness scalpel wounds on the backs of mice and digital photography/image analysis and in vivo bioluminescence imaging were used to measure wound healing and the bacterial burden. Subcutaneous vancomycin, daptomycin, and linezolid similarly reduced the lesion sizes and bacterial burden. Oral linezolid, clindamycin, and doxycycline all decreased the lesion sizes and bacterial burden. Oral trimethoprim-sulfamethoxazole decreased the bacterial burden but did not decrease the lesion size. Topical mupirocin and retapamulin ointments both reduced the bacterial burden. However, the petrolatum vehicle ointment for retapamulin, but not the polyethylene glycol vehicle ointment for mupirocin, promoted wound healing and initially increased the bacterial burden. Finally, in type 2 diabetic mice, subcutaneous linezolid and daptomycin had the most rapid therapeutic effect compared with vancomycin. Taken together, this mouse model of CA-MRSA wound infection, which utilizes in vivo bioluminescence imaging to monitor the bacterial burden, represents an alternative method to evaluate the preclinical in vivo efficacy of systemic and topical antimicrobial agents. PMID:23208713

  5. The extent to which methyl salicylate is required for signaling systemic acquired resistance is dependent on exposure to light after infection.

    PubMed

    Liu, Po-Pu; von Dahl, Caroline C; Klessig, Daniel F

    2011-12-01

    Systemic acquired resistance (SAR) is a state of heightened defense to a broad spectrum of pathogens that is activated throughout a plant following local infection. Development of SAR requires the translocation of one or more mobile signals from the site of infection through the vascular system to distal (systemic) tissues. The first such signal identified was methyl salicylate (MeSA) in tobacco (Nicotiana tabacum). Subsequent studies demonstrated that MeSA also serves as a SAR signal in Arabidopsis (Arabidopsis thaliana) and potato (Solanum tuberosum). By contrast, another study suggested that MeSA is not required for SAR in Arabidopsis and raised questions regarding its signaling role in tobacco. Differences in experimental design, including the developmental age of the plants, the light intensity, and/or the strain of bacterial pathogen, were proposed to explain these conflicting results. Here, we demonstrate that the length of light exposure that plants receive after the primary infection determines the extent to which MeSA is required for SAR signaling. When the primary infection occurred late in the day and as a result infected plants received very little light exposure before entering the night/dark period, MeSA and its metabolizing enzymes were essential for SAR development. In contrast, when infection was done in the morning followed by 3.5 h or more of exposure to light, SAR developed in the absence of MeSA. However, MeSA was generally required for optimal SAR development. In addition to resolving the conflicting results concerning MeSA and SAR, this study underscores the importance of environmental factors on the plant's response to infection.

  6. Molecular characteristics of community-acquired methicillin-resistant Staphylococcus aureus strains isolated from outpatients with skin and soft tissue infections in Wuhan, China.

    PubMed

    Liu, Xiaoli; Liang, Jiansheng; Jiang, Yuanshan; Wang, Bin; Yuan, Hong; Zhang, Lihua; Zhou, Yanfei; Xu, Huiqiong; Zhou, Wang

    2016-06-01

    This study aims to investigate the antimicrobial susceptibility, molecular characteristics and virulence genes of community-acquired methicillin-resistant ITALIC! Staphylococcus aureus(CA-MRSA) isolates with skin and soft tissue infections (SSTIs). Outpatients with SSTIs visiting five medical and health institutions were enrolled from 2011 to 2013. Available ITALIC! S. aureus isolates were characterized by antimicrobial susceptibility testing, and detection of PVL genes. For CA-MRSA isolates, we performed typing of staphylococcal cassette chromosome ITALIC! mec(SCC ITALIC! mec), multi locus sequence typing (MLST) and carriage of 27 virulence genes. A total of 203 ITALIC! S. aureusstrains were isolated from 1400 outpatients with SSTIs, and 21 (10.3%) were CA-MRSA isolates. The positive rate of PVL genes among ITALIC! S. aureus, CA-MRSA and methicillin-susceptible ITALIC! S. aureus(MSSA) isolates were 39.4%, 71.4% and 35.7%, respectively. CA-MRSA strains had greater sensitivity to non-β-lactam antimicrobial agents. All CA-MRSA isolates belonged to SCC ITALIC! mecIV and V, accounting for 47.6% and 52.4%, respectively. ST59 was the most common lineage accounting for 76.2%; ST59-SCC ITALIC! mecIVa-PVL-positive clone was found to be the predominant clone, accounting for 38.1%. All CA-MRSA isolates were found to be positive for one or more virulence genes, 28.6% of isolates carried PVL, ITALIC! seb, ITALIC! sek, ITALIC! seq, ITALIC! hla, ITALIC! hlb, ITALIC! hldand ITALIC! hlg-2. CA-MRSA infections were relatively uncommon in outpatients with SSTIs, but they carried many virulence genes, ST59-SCC ITALIC! mecIV a-PVL-positive clone was the predominant clone in Wuhan, China.

  7. Long-Term Treatment with Erlotinib for EGFR Wild-Type Non-Small Cell Lung Cancer: A Case Report.

    PubMed

    Polychronidou, Genovefa; Papakotoulas, Pavlos

    2013-01-01

    The epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) gefitinib and erlotinib are known to have greater efficacy in EGFR mutation-positive non-small cell lung cancer (NSCLC), although erlotinib also has activity in wild-type disease. We report the successful long-term maintenance treatment of a patient with EGFR wild-type NSCLC with gefitinib and later erlotinib. The patient (male; 44 years old; smoker) was diagnosed with EGFR wild-type NSCLC after computer tomography had revealed a mediastinal mass, and histology and mutation testing had identified the tumor as an EGFR wild-type grade 3 adenocarcinoma. The patient received multiple rounds of chemotherapy, followed by gefitinib maintenance (3 years). Later on, he received erlotinib maintenance and developed a persistent rash (grade 1/2) that lasted throughout the treatment. The patient's condition has remained stable on erlotinib for more than 5 years, with no evidence of progression. We describe the patient's disease course and treatment in the context of EGFR TKI therapy and the prognostic factors for long-term clinical outcomes of NSCLC, including the development of erlotinib-induced rash.

  8. Role of erlotinib in first-line and maintenance treatment of advanced non-small-cell lung cancer

    PubMed Central

    Reguart, Noemí; Cardona, Andrés Felipe; Rosell, Rafael

    2010-01-01

    Erlotinib hydrochloride (Tarceva®) is a member of a class of small molecule inhibitors that targets the tyrosine kinase domain of the epidermal growth factor receptor (EGFR), with anti-tumor activity in preclinical models. Erlotinib represents a new-generation of agents known as “targeted therapies” designed to act upon cancer cells by interfering with aberrant specific activated pathways needed for tumor growth, angiogenesis and cell survival. Since its approval in November 2004 for the treatment of locally advanced or metastatic non-small cell lung cancer (NSCLC) after the failure of at least one prior chemotherapy regimen and with a view to improving patients’ outcomes and prevent symptoms, the scientific community has evaluated the potential role of erlotinib in other scenarios such as in maintenance therapy and, in first-line setting for a selected population based on biological markers of response such as mutations of the EGFR. The convenient once-a-day pill administration and the good toxicity profile of erlotinib make it a reasonable candidate for testing in this context. This report provides a review of the role of erlotinib therapy in advanced NSCLC. It summarizes current data and perspectives of erlotinib in upfront treatment and maintenance for advanced NSCLC as well as looking at candidate biomarkers of response to these new targeted-agents. PMID:21188105

  9. Combination of erlotinib and EGCG induces apoptosis of head and neck cancers through posttranscriptional regulation of Bim and Bcl-2.

    PubMed

    Haque, Abedul; Rahman, Mohammad Aminur; Chen, Zhuo Georgia; Saba, Nabil F; Khuri, Fadlo R; Shin, Dong M; Ruhul Amin, A R M

    2015-07-01

    Combinatorial approaches using two or more compounds are gaining increasing attention for cancer therapy. We have previously reported that the combination of the EGFR-TKI erlotinib and epigallocatechin-3-gallate (EGCG) exhibited synergistic chemopreventive effects in head and neck cancers by inducing the expression of Bim, p21, p27, and by inhibiting the phosphorylation of ERK and AKT and expression of Bcl-2. In the current study, we further investigated the mechanism of regulation of Bim, Bcl-2, p21 and p27, and their role in apoptosis. shRNA-mediated silencing of Bim significantly inhibited apoptosis induced by the combination of erlotinib and EGCG (p = 0.005). On the other hand, overexpression of Bcl-2 markedly protected cells from apoptosis (p = 0.003), whereas overexpression of constitutively active AKT only minimally protected cells from apoptosis induced by the combination of the two compounds. Analysis of mRNA expression by RT-PCR revealed that erlotinib, EGCG and their combination had no significant effects on the mRNA expression of Bim, p21, p27 or Bcl-2 suggesting the post-transcriptional regulation of these molecules. Furthermore, we found that erlotinib or the combination of EGCG and erlotinib inhibited the phosphorylation of Bim and stabilized Bim after inhibition of protein translation by cycloheximide. Taken together, our results strongly suggest that the combination of erlotinib and EGCG induces apoptosis of SCCHN cells by regulating Bim and Bcl-2 at the posttranscriptional level.

  10. Effect of Sulindac and Erlotinib vs Placebo on Duodenal Neoplasia in Familial Adenomatous Polyposis

    PubMed Central

    Samadder, N. Jewel; Neklason, Deborah W.; Boucher, Kenneth M.; Byrne, Kathryn R.; Kanth, Priyanka; Samowitz, Wade; Jones, David; Tavtigian, Sean V.; Done, Michelle W.; Berry, Therese; Jasperson, Kory; Pappas, Lisa; Smith, Laurel; Sample, Danielle; Davis, Rian; Topham, Matthew K.; Lynch, Patrick; Strait, Elena; McKinnon, Wendy; Burt, Randall W.; Kuwada, Scott K.

    2016-01-01

    IMPORTANCE Patients with familial adenomatous polyposis (FAP) are at markedly increased risk for duodenal polyps and cancer. Surgical and endoscopic management of duodenal neoplasia is difficult and chemoprevention has not been successful. OBJECTIVE To evaluate the effect of a combination of sulindac and erlotinib on duodenal adenoma regression in patients with FAP. DESIGN, SETTING, AND PARTICIPANTS Double-blind, randomized, placebo-controlled trial, enrolling 92 participants with FAP, conducted from July 2010 through June 2014 at Huntsman Cancer Institute in Salt Lake City, Utah. INTERVENTIONS Participants with FAP were randomized to sulindac (150 mg) twice daily and erlotinib (75 mg) daily (n = 46) vs placebo (n = 46) for 6 months. MAIN OUTCOMES AND MEASURES The total number and diameter of polyps in the proximal duodenum were mapped at baseline and 6 months. The primary outcome was change in total polyp burden at 6 months. Polyp burden was calculated as the sum of the diameters of polyps. The secondary outcomes were change in total duodenal polyp count, change in duodenal polyp burden or count stratified by genotype and initial polyp burden, and percentage of change from baseline in duodenal polyp burden. RESULTS Ninety-two participants (mean age, 41 years [range, 24–55]; women, 56 [61%]) were randomized when the trial was stopped by the external data and safety monitoring board because the second preplanned interim analysis met the prespecified stopping rule for superiority. Grade 1 and 2 adverse events were more common in the sulindac-erlotinib group, with an acne-like rash observed in 87% of participants receiving treatment and 20% of participants receiving placebo (P < .001). Only 2 participants experienced grade 3 adverse events. OutcomeBaseline6-moFollow-upMedianChangeBetween-GroupDifference (95% CI)PValueMedian Duodenal Polyp Burden, mmSulindac-erlotinib29.019.5−8.5−19.0 (−32.0 to −10.9)<.001Placebo23.031.08.0Median Duodenal Polyp Count, No.Sulindac-erlotinib

  11. Crosstalk with cancer-associated fibroblasts induces resistance of non-small cell lung cancer cells to epidermal growth factor receptor tyrosine kinase inhibition

    PubMed Central

    Choe, Chungyoul; Shin, Yong-Sung; Kim, Changhoon; Choi, So-Jung; Lee, Jinseon; Kim, So Young; Cho, Yong Beom; Kim, Jhingook

    2015-01-01

    Although lung cancers with activating mutations in the epidermal growth factor receptor (EGFR) are highly sensitive to selective EGFR tyrosine kinase inhibitors (TKIs), these tumors invariably develop acquired drug resistance. Host stromal cells have been found to have a considerable effect on the sensitivity of cancer cells to EGFR TKIs. Little is known, however, about the signaling mechanisms through which stromal cells contribute to the response to EGFR TKI in non-small cell lung cancer. This work examined the role of hedgehog signaling in cancer-associated fibroblast (CAF)-mediated resistance of lung cancer cells to the EGFR TKI erlotinib. PC9 cells, non-small cell lung cancer cells with EGFR-activating mutations, became resistant to the EGFR TKI erlotinib when cocultured in vitro with CAFs. Polymerase chain reaction and immunocytochemical assays showed that CAFs induced epithelial to mesenchymal transition phenotype in PC9 cells, with an associated change in the expression of epithelial to mesenchymal transition marker proteins including vimentin. Importantly, CAFs induce upregulation of the 7-transmembrane protein smoothened, the central signal transducer of hedgehog, suggesting that the hedgehog signaling pathway is active in CAF-mediated drug resistance. Indeed, downregulation of smoothened activity with the smoothened antagonist cyclopamine induces remodeling of the actin cytoskeleton independently of Gli-mediated transcriptional activity in PC9 cells. These findings indicate that crosstalk with CAFs plays a critical role in resistance of lung cancer to EGFR TKIs through induction of the epithelial to mesenchymal transition and may be an ideal therapeutic target in lung cancer. PMID:26676152

  12. Community-acquired pneumonia.

    PubMed

    Prina, Elena; Ranzani, Otavio T; Torres, Antoni

    2015-09-12

    Community-acquired pneumonia causes great mortality and morbidity and high costs worldwide. Empirical selection of antibiotic treatment is the cornerstone of management of patients with pneumonia. To reduce the misuse of antibiotics, antibiotic resistance, and side-effects, an empirical, effective, and individualised antibiotic treatment is needed. Follow-up after the start of antibiotic treatment is also important, and management should include early shifts to oral antibiotics, stewardship according to the microbiological results, and short-duration antibiotic treatment that accounts for the clinical stability criteria. New approaches for fast clinical (lung ultrasound) and microbiological (molecular biology) diagnoses are promising. Community-acquired pneumonia is associated with early and late mortality and increased rates of cardiovascular events. Studies are needed that focus on the long-term management of pneumonia.

  13. Erlotinib-associated interstitial lung disease in advanced pancreatic carcinoma: a case report and literature review.

    PubMed

    Macerelli, Marianna; Mazzer, Micol; Foltran, Luisa; Cardellino, Giovanni Gerardo; Aprile, Giuseppe

    2015-07-24

    The combination of erlotinib and gemcitabine is a recognized option for patients with metastatic pancreatic cancer whose common adverse events such as skin rash, diarrhea, or fatigue are usually easily manageable. Interstitial lung disease (ILD) is a life-threatening toxicity reported in patients with non-small-cell lung cancers treated with epidermal growth factor receptor-tyrosine kinase inhibitors or gemcitabine. This side effect is extremely rare in patients with pancreatic cancer. We report fatal treatment-related ILD that occurred in a 67-year-old patient with metastatic pancreatic cancer. Risk factors and pathophysiology of ILD need further investigation but caution is highly recommended for patients with an underlying pulmonary disease when using erlotinib in monotherapy or combination therapy.

  14. Radiotherapy and Erlotinib Combined: Review of the Preclinical and Clinical Evidence

    PubMed Central

    Mehta, Vivek K.

    2012-01-01

    Epidermal growth factor receptor (EGFR) is often overexpressed in tumors and has been associated with poor prognosis in some cancer types. The introduction of inhibitors of EGFR, such as erlotinib, represents an important recent advance in the targeted treatment of cancer. Several studies have evaluated inhibitors of EGFR in combination with radiotherapy, and a strong biologic rationale exists for the use of this combination in certain cancer types, including head and neck squamous cell carcinoma, non-small cell lung cancer, glioblastoma, esophageal cancer, and pancreatic cancer. Preclinical and clinical studies are underway to evaluate the combination of erlotinib with radiotherapy. To date, the results suggest that this approach is at least feasible and may result in modest improvement in outcomes compared with either modality alone. PMID:22645717

  15. First report in South America of companion animal colonization by the USA1100 clone of community-acquired meticillin-resistant Staphylococcus aureus (ST30) and by the European clone of methicillin-resistant Staphylococcus pseudintermedius (ST71)

    PubMed Central

    2013-01-01

    Background Methicillin-resistant staphylococci can colonize and cause diseases in companion animals. Unfortunately, few molecular studies have been carried out in Brazil and other countries with the aim of characterizing these isolates. Consequently, little is known about the potential role of companion animals in transmitting these resistant bacteria to humans. In this work we searched for mecA gene among Staphylococcus isolates obtained from nasal microbiota of 130 healthy dogs and cats attended in a veterinary clinic located in the west region of Rio de Janeiro. The isolates recovered were identified to the species level and characterized using molecular tools. Results A community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) isolate related to USA1100 (Southwest Pacific clone) and susceptible to all non-β-lactams was detected in a cat (1.7%, 1/60). Another coagulase-positive isolate harboring mecA was recovered from a dog (1.4%, 1/70) and identified as Staphylococcus pseudintermedius (MRSP) related to the European clone (ST71). The two isolates of Staphylococcus conhii subsp. urealyticus (1.4%, 1/70 dogs and 1.7%, 1/60 cats), similarly to the MRSP isolate, also presented high-level multiresistance. The majority of the methicillin-resistant coagulase-negative staphylococci recovered were Staphylococcus saprophyticus (5.7%, 4/70 dogs and 6.7%, 4/60 cats) and all clustered into the same PFGE type. Conclusions This work demonstrates that mecA-harboring Staphylococcus isolates are common members of the nasal microbiota of the healthy companion animals studied (9.2%, 12/130 animals), including some high-level multiresistant isolates of S. pseudintermedius and S. conhii subsp. urealyticus. The detection, for the first time in South America, of USA1100-related CA-MRSA and of ST71 MRSP (European clone), colonizing companion animals, is of concern. Both S. pseudintermedius and S. aureus are important agents of infections for animals. The USA1100 CA

  16. Peroxisome proliferator-activated receptor γ agonist efatutazone impairs transforming growth factor β2-induced motility of epidermal growth factor receptor tyrosine kinase inhibitor-resistant lung cancer cells.

    PubMed

    Serizawa, Masakuni; Murakami, Haruyasu; Watanabe, Masaru; Takahashi, Toshiaki; Yamamoto, Nobuyuki; Koh, Yasuhiro

    2014-06-01

    Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKI) are effective for non-small cell lung cancers (NSCLC) with EGFR-activating mutations. However, most responders develop resistance. Efatutazone, a novel peroxisome proliferator-activated receptor gamma (PPARγ) agonist, is currently under clinical evaluation; it has antiproliferative effects and induces cellular morphological changes and differentiation. The present study investigated the effects of efatutazone in EGFR-TKI-resistant NSCLC cells, while focusing on cell motility. The PC-9-derived NSCLC cell lines PC-9ER and PC-9ZD, resistant to EGFR-TKI due to v-crk avian sarcoma virus CT10 oncogene homolog-like (CRKL) amplification-induced phosphatidylinositol 3-kinase (PI3K)/v-akt murine thymoma viral oncogene homolog (AKT) activation and an EGFR T790M mutation, respectively, were used. These cells exhibit enhanced cell motility due to transforming growth factor β (TGF-β)/Smad2 family member 2 (Smad2) pathway activation. Efatutazone had no growth-inhibitory effect on the tested cells but inhibited the motility of EGFR-TKI-resistant cells in wound closure and transwell assays. Efatutazone plus erlotinib treatment provided greater inhibition of PC-9ER cell migration than efatutazone or erlotinib alone. Efatutazone suppressed increased TGF-β2 secretion from both cell lines (shown by ELISA) and downregulation of TGF-β2 transcription (observed by quantitative RT-PCR). Immunoblot analysis and luciferase assays revealed that efatutazone suppressed Smad2 phosphorylation and its transcriptional activity. These results suggest that efatutazone inhibits cell motility by antagonizing the TGF-β/Smad2 pathway and effectively prevents metastasis in NSCLC patients with acquired resistance to EGFR-TKI regardless of the resistance mechanism.

  17. Preoperative Radiation Therapy With Concurrent Capecitabine, Bevacizumab, and Erlotinib for Rectal Cancer: A Phase 1 Trial

    SciTech Connect

    Das, Prajnan; Eng, Cathy; Rodriguez-Bigas, Miguel A.; Chang, George J.; Skibber, John M.; You, Y. Nancy; Maru, Dipen M.; Munsell, Mark F.; Clemons, Marilyn V.; Kopetz, Scott E.; Garrett, Christopher R.; Shureiqi, Imad; Delclos, Marc E.; Krishnan, Sunil; Crane, Christopher H.

    2014-02-01

    Purpose: The goal of this phase 1 trial was to determine the maximum tolerated dose (MTD) of concurrent capecitabine, bevacizumab, and erlotinib with preoperative radiation therapy for rectal cancer. Methods and Materials: Patients with clinical stage II to III rectal adenocarcinoma, within 12 cm from the anal verge, were treated in 4 escalating dose levels, using the continual reassessment method. Patients received preoperative radiation therapy with concurrent bevacizumab (5 mg/kg intravenously every 2 weeks), erlotinib, and capecitabine. Capecitabine dose was increased from 650 mg/m{sup 2} to 825 mg/m{sup 2} orally twice daily on the days of radiation therapy; erlotinib dose was increased from 50 mg orally daily in weeks 1 to 3, to 50 mg daily in weeks 1 to 6, to 100 mg daily in weeks 1 to 6. Patients underwent surgery at least 9 weeks after the last dose of bevacizumab. Results: A total of 19 patients were enrolled, and 18 patients were considered evaluable. No patient had grade 4 acute toxicity, and 1 patient had grade 3 acute toxicity (hypertension). The MTD was not reached. All 18 evaluable patients underwent surgery, with low anterior resection in 7 (39%), proctectomy with coloanal anastomosis in 4 patients (22%), posterior pelvic exenteration in 1 (6%), and abdominoperineal resection in 6 (33%). Of the 18 patients, 8 (44%) had pathologic complete response, and 1 had complete response of the primary tumor with positive nodes. Three patients (17%) had grade 3 postoperative complications (ileus, small bowel obstruction, and infection). With a median follow-up of 34 months, 1 patient developed distant metastasis, and no patient had local recurrence or died. The 3-year disease-free survival was 94%. Conclusions: The combination of preoperative radiation therapy with concurrent capecitabine, bevacizumab, and erlotinib was well tolerated. The pathologic complete response rate appears promising and may warrant further investigation.

  18. Phase 2 trial of erlotinib plus sirolimus in adults with recurrent glioblastoma

    PubMed Central

    Reardon, David A.; Desjardins, Annick; Vredenburgh, James J.; Gururangan, Sridharan; Friedman, Allan H.; Herndon, James E.; Marcello, Jennifer; Norfleet, Julie A.; McLendon, Roger E.; Sampson, John H.; Friedman, Henry S.

    2010-01-01

    We evaluated the anti-tumor activity and safety of erlotinib, a receptor tyrosine kinase inhibitor of the epidermal growth factor receptor, plus sirolimus, an inhibitor of the mammalian target of rapamycin, among patients with recurrent glioblastoma (GBM) in a phase 2, open-label, single-arm trial. Thirty-two patients received daily erlotinib and sirolimus. The doses of erlotinib and sirolimus were 150 mg and 5 mg for patients not on concurrent CYP3A-inducing anti-epileptics (EIAEDS), and 450 mg and 10 mg for patients on EIAEDS. Evaluations were performed every two months. The primary endpoint was 6-month progression-free survival and secondary endpoints included safety and overall survival. Archival tumor samples were assessed for EGFR, EGFRvIII, PTEN, pAKT and pS6. Enrolled patients were heavily pre-treated including 53% who had received three or more prior chemotherapy agents and 28% who had received prior bevacizumab therapy. The most common grade ≥2 adverse events were rash (59%), mucositis (34%) and diarrhea (31%). Grade 3 or higher events were rare. Best radiographic response included stable disease in 15 patients (47%); no patients achieved either a CR or PR. The estimated 6-month progression-free survival was 3.1% for all patients. Progression-free survival was better for patients not on EIAEDs (P = 0.03). Tumor markers failed to show an association with PFS except for increased pAKT expression which achieved borderline significance (P = 0.045). Although neither rash nor diarrhea had an association with outcome, hyperlipidemia was associated with longer PFS (P = 0.029). Erlotinib plus sirolimus was well tolerated but had negligible activity among unselected recurrent GBM patients. PMID:19562254

  19. Phase II Trials of Erlotinib or Gefitinib in Patients with Recurrent Meningioma

    PubMed Central

    Norden, Andrew D.; Raizer, Jeffrey J.; Abrey, Lauren E.; Lamborn, Kathleen R.; Lassman, Andrew B.; Chang, Susan M.; Yung, W.K. Alfred; Gilbert, Mark R.; Fine, Howard A.; Mehta, Minesh; DeAngelis, Lisa M.; Cloughesy, Timothy F.; Robins, H. Ian; Aldape, Kenneth; Dancey, Janet; Prados, Michael D.; Lieberman, Frank; Wen, Patrick Y.

    2013-01-01

    There are no established treatments for recurrent meningioma when surgical and radiation options are exhausted. The epidermal growth factor receptor (EGFR) is often over-expressed in meningiomas and may promote tumor growth. In open label, single arm phase II studies of the EGFR inhibitors gefitinib (NABTC 00-01) and erlotinib (NABTC 01-03) for recurrent malignant gliomas, we included exploratory subsets of recurrent meningioma patients. We have pooled the data and report the results here. Patients with recurrent histologically confirmed meningiomas with no more than 2 previous chemotherapy regimens were treated with gefitinib 500 mg/day or erlotinib 150 mg/day until tumor progression or unacceptable toxicity. Twenty-five eligible patients were enrolled with median age 57 years (range 29–81) and median Karnofsky performance status (KPS) score 90 (range 60–100). Sixteen patients (64%) received gefitinib and 9 (36%) erlotinib. Eight patients (32%) had benign tumors, 9 (36%) atypical, and 8 (32%) malignant. For benign tumors, the 6-month progression-free survival (PFS6) was 25%, 12-month PFS (PFS12) 13%, 6-month overall survival (OS6) 63%, and 12-month OS (OS12) 50%. For atypical and malignant tumors, PFS6 was 29%, PFS12 18%, OS6 71%, and OS12 65%. The PFS and OS were not significantly different by histology. There were no objective imaging responses, but 8 patients (32%) maintained stable disease. Although treatment was well-tolerated, neither gefitinib nor erlotinib appear to have significant activity against recurrent meningioma. The role of EGFR inhibitors in meningiomas is unclear. Evaluation of multi-targeted inhibitors and EGFR inhibitors in combination with other targeted molecular agents may be warranted. PMID:19562255

  20. Hepatic metastasis is a poor predictive marker for erlotinib in lung adenocarcinoma.

    PubMed

    He, Yayi; Wang, Yan; Zhang, Shijia; Ren, Shengxiang; Li, Jiayu; Zhou, Caicun

    2016-09-01

    Lung cancer is the leading cause of cancer related death worldwide and most of lung cancer patients have had metastases when they are diagnosed. With respect to chemotherapy, target therapy is a more effective and less toxic treatments. The epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs), such as gefitinib or erlotinib, are one of the representatives of targeted therapy which have been widely used in first line, maintenance and 2nd/3rd line therapy among advanced non-small cell lung cancer (NSCLC). But those with hepatic metastases may insensitive to EGFR-TKIs due to MET activation by hepatocyte growth factor (HGF). In our retrospective analysis, 164 lung adenocarcinoma patients with known epidermal growth factor receptor (EGFR) mutation status who received the treatment of erlotinib as 2nd/3rd line setting were reviewed. The disease control rate (DCR) in patients without hepatic metastases group was higher than that in patients with hepatic metastases (66.1% vs 54.5%, p<0.001). In EGFR mutation-positive patients, median PFS was significantly longer in patients without hepatic metastases than that in those with hepatic metastases (9.9months 95% CI 7.74-12.06months vs. 7.9months 95% CI 5.88-9.92months; p=0.017). Therefore, we assume that hepatic metastasis may be a poor predictive marker for erlotinib in lung adenocarcinoma. PMID:27515192

  1. Antimicrobial susceptibility and serotype distribution of Streptococcus pneumoniae isolated from patients with community-acquired pneumonia and molecular analysis of multidrug-resistant serotype 19F and 23F strains in Japan.

    PubMed

    Qin, L; Watanabe, H; Yoshimine, H; Guio, H; Watanabe, K; Kawakami, K; Iwagaki, A; Nagai, H; Goto, H; Kuriyama, T; Fukuchi, Y; Matsushima, T; Kudoh, S; Shimada, K; Matsumoto, K; Nagatake, T; Mizota, T; Oishi, K

    2006-12-01

    A nationwide study was undertaken to determine the susceptibility to penicillin and serotypes of Streptococcus pneumoniae in Japan. S. pneumoniae was isolated from 114 adult patients with community-acquired pneumonia over 22 months at 20 hospitals and medical centres in different regions in Japan. All but five isolates were from sputum. Forty-eight isolates (42.1%) were susceptible, 40 (35.1%) showed intermediate resistance (MIC, 0.12-1.0 microg/ml) and 26 (22.8%) were resistant (MIC, >or=2.0 microg/ml) to penicillin G. All isolates were susceptible to ceftriaxone (breakpoint 1 microg/ml), imipenem (4 microg/ml) and vancomycin (4 microg/ml). Most were resistant to erythromycin, clarithromycin and azithromycin; only two were resistant to levofloxacin. Differences were found in the distribution of serotypes among isolates showing susceptibility to penicillin (predominant types 3, 6B, and 19F), intermediate resistance (6B, 14, 19F, and 23F) and full resistance (19F and 23F). PFGE typing showed that 14 of the 25 strains of serotype 19F had a single DNA profile, pattern A, a pattern closely similar to that of the Taiwan multidrug-resistant 19F clone. Twelve pattern A strains were not susceptible to penicillin but carried the macrolide resistance gene mef(A). The DNA profiles of the 15 strains of 23F were also heterogeneous but six were highly similar (pattern b) yet distinct from the Spanish multidrug-resistant 23F clone although possibly related to the Taiwan multidrug-resistant 23F clone. The pattern b strains were not susceptible to penicillin and also harboured either mef(A) or erm(B). Our results indicate that multidrug-resistant pneumococci are spreading rapidly in Japan. Efforts to prevent the spread of the pandemic multidrug-resistant serotypes should be intensified. PMID:16650327

  2. JAK2 inhibition sensitizes resistant EGFR-mutant lung adenocarcinoma to tyrosine kinase inhibitors

    PubMed Central

    Gao, Sizhi P.; Chang, Qing; Mao, Ninghui; Daly, Laura A.; Vogel, Robert; Chan, Tyler; Liu, Shu Hui; Bournazou, Eirini; Schori, Erez; Zhang, Haiying; Brewer, Monica Red; Pao, William; Morris, Luc; Ladanyi, Marc; Arcila, Maria; Manova-Todorova, Katia; de Stanchina, Elisa; Norton, Larry; Levine, Ross L.; Altan-Bonnet, Gregoire; Solit, David; Zinda, Michael; Huszar, Dennis; Lyden, David; Bromberg, Jacqueline F.

    2016-01-01

    Lung adenocarcinomas with mutant epidermal growth factor receptor (EGFR) respond to EGFR-targeted tyrosine kinase inhibitors (TKIs), but resistance invariably occurs. We found that the Janus kinase (JAK)/signal transduction and activator of transcription 3 (STAT3) signaling pathway was aberrantly increased in TKI-resistant EGFR-mutant non–small cell lung cancer (NSCLC) cells. JAK2 inhibition restored sensitivity to the EGFR inhibitor erlotinib in TKI-resistant cell lines and xenograft models of EGFR-mutant TKI-resistant lung cancer. JAK2 inhibition uncoupled EGFR from its negative regulator, suppressor of cytokine signaling 5 (SOCS5), consequently increasing EGFR abundance and restoring the tumor cells’ dependence on EGFR signaling. Furthermore, JAK2 inhibition led to heterodimerization of mutant and wild-type EGFR subunits, the activity of which was then blocked by TKIs. Our results reveal a mechanism whereby JAK2 inhibition overcomes acquired resistance to EGFR inhibitors and support the use of combination therapy with JAK and EGFR inhibitors for the treatment of EGFR-dependent NSCLC. PMID:27025877

  3. High Pdr12 levels in spoilage yeast (Saccharomyces cerevisiae) correlate directly with sorbic acid levels in the culture medium but are not sufficient to provide cells with acquired resistance to the food preservative.

    PubMed

    Papadimitriou, Minas N B; Resende, Catarina; Kuchler, Karl; Brul, Stanley

    2007-01-25

    Sorbic acid is a commonly used food preservative against yeast and fungal food spoilage. Understanding its effect on the molecular physiology of yeast cells will allow the food industry to develop knowledge-based strategies to make more optimal use of its preservative action. Here we show that the yeast membrane protein Pdr12, previously shown to be prominently involved in sorbic acid resistance development in laboratory strains, was strongly induced by the presence of sorbic acid in the culture medium in Saccharomyces strains isolated from spoiled foods. Induction of Pdr12 expression was seen both under laboratory conditions and upon growth in a commercial soft drink. Induction was rapid and maintained for the duration of the stress. No Pdr12-like protein induction was seen in Zygosaccharomyces bailii or Zygosaccharomyces lentus, two well-known beverages spoilage organisms. Finally, unexpectedly, our studies showed for the first time that pre-inducing Pdr12p to maximal levels by subjecting cells to a mild sorbic acid stress did not lead to cells with an acquired resistance. Neither more rapid growth in the presence of the acid nor growth at higher sorbic acid concentrations at a given environmental pH was observed. Thus we have shown that while important in resistance development against sorbic acid, by itself induction of the pump is not sufficient to acquire resistance to the preservative.

  4. Myc induced miR-144/451 contributes to the acquired imatinib resistance in chronic myelogenous leukemia cell K562

    SciTech Connect

    Liu, Li; Wang, Sitao; Chen, Renan; Wu, Yanlan; Zhang, Bei; Huang, Siyong; Zhang, Jingyi; Xiao, Fang; Wang, Meng; Liang, Yingmin

    2012-08-24

    Highlights: Black-Right-Pointing-Pointer Increased c-myc expression in imatinib resistant CML cells. Black-Right-Pointing-Pointer c-myc contributes the imatinib resistance in CML cells. Black-Right-Pointing-Pointer c-myc transcriptionally reduces the expression of miR-144/451 in K562R cells. Black-Right-Pointing-Pointer Restoration of miR-144/451 reverses the resistance of K562R cells to imatinib. -- Abstract: Imatinib resistance remains the big hurdle for CML therapy. Previous study reveals that c-myc is important for bcr-abl CML cell proliferation, while its role in imatinib resistance is largely unknown. In this study, we first found that c-myc expression is upregulated in imatinib resistant K562R cells, which in turn enhances the expression of miR-144/451. Knockdown of c-myc or restoration of miR-144/451 in the K562R cells sensitizes K562R cells to imatinib therapy. Our study here reveals an regulatory pathway between myc and miR-144/451 and highlights that targeting either myc or miR-144/451 might be valuable for eliminating the imatinib resistant CML cells.

  5. Phase 2 Study of Erlotinib Combined With Adjuvant Chemoradiation and Chemotherapy in Patients With Resectable Pancreatic Cancer

    SciTech Connect

    Herman, Joseph M.; Fan, Katherine Y.; Wild, Aaron T.; Hacker-Prietz, Amy; Wood, Laura D.; Blackford, Amanda L.; Ellsworth, Susannah; Zheng, Lei; Le, Dung T.; De Jesus-Acosta, Ana; Hidalgo, Manuel; Donehower, Ross C.; Schulick, Richard D.; Edil, Barish H.; Choti, Michael A.; Hruban, Ralph H.; and others

    2013-07-15

    Purpose: Long-term survival rates for patients with resected pancreatic ductal adenocarcinoma (PDAC) have stagnated at 20% for more than a decade, demonstrating the need to develop novel adjuvant therapies. Gemcitabine-erlotinib therapy has demonstrated a survival benefit for patients with metastatic PDAC. Here we report the first phase 2 study of erlotinib in combination with adjuvant chemoradiation and chemotherapy for resected PDAC. Methods and Materials: Forty-eight patients with resected PDAC received adjuvant erlotinib (100 mg daily) and capecitabine (800 mg/m{sup 2} twice daily Monday-Friday) concurrently with intensity modulated radiation therapy (IMRT), 50.4 Gy over 28 fractions followed by 4 cycles of gemcitabine (1000 mg/m{sup 2} on days 1, 8, and 15 every 28 days) and erlotinib (100 mg daily). The primary endpoint was recurrence-free survival (RFS). Results: The median follow-up time was 18.2 months (interquartile range, 13.8-27.1). Lymph nodes were positive in 85% of patients, and margins were positive in 17%. The median RFS was 15.6 months (95% confidence interval [CI], 13.4-17.9), and the median overall survival (OS) was 24.4 months (95% CI, 18.9-29.7). Multivariate analysis with adjustment for known prognostic factors showed that tumor diameter >3 cm was predictive for inferior RFS (hazard ratio, 4.01; P=.001) and OS (HR, 4.98; P=.02), and the development of dermatitis was associated with improved RFS (HR, 0.27; P=.009). During CRT and post-CRT chemotherapy, the rates of grade 3/4 toxicity were 31%/2% and 35%/8%, respectively. Conclusion: Erlotinib can be safely administered with adjuvant IMRT-based CRT and chemotherapy. The efficacy of this regimen appears comparable to that of existing adjuvant regimens. Radiation Therapy Oncology Group 0848 will ultimately determine whether erlotinib produces a survival benefit in patients with resected pancreatic cancer.

  6. Phase II Trial of Erlotinib during and after Radiotherapy in Children with Newly Diagnosed High-Grade Gliomas

    PubMed Central

    Qaddoumi, Ibrahim; Kocak, Mehmet; Pai Panandiker, Atmaram S.; Armstrong, Gregory T.; Wetmore, Cynthia; Crawford, John R.; Lin, Tong; Boyett, James M.; Kun, Larry E.; Boop, Fredrick A.; Merchant, Thomas E.; Ellison, David W.; Gajjar, Amar; Broniscer, Alberto

    2014-01-01

    Background: Epidermal growth factor receptor is overexpressed in most pediatric high-grade gliomas (HGG). Since erlotinib had shown activity in adults with HGG, we conducted a phase II trial of erlotinib and local radiotherapy (RT) in children with newly diagnosed HGG. Methods: Following maximum surgical resection, patients between 3 and 21 years with non-metastatic HGG received local RT at 59.4 Gy (54 Gy for spinal tumors and those with ≥70% brain involvement). Erlotinib started on day 1 of RT (120 mg/m2 per day) and continued for 2 years unless there was tumor progression or intolerable toxicities. The 2-year progression-free survival (PFS) was estimated for patients with intracranial anaplastic astrocytoma (AA) and glioblastoma (GBM). Results: Median age at diagnosis for 41 patients with intracranial tumors (21 with GBM and 20 with AA) was 10.9 years (range, 3.3–19 years). The 2-year PFS for patients with AA and GBM was 15 ± 7 and 19 ± 8%, respectively. Only five patients remained alive without tumor progression. Twenty-six patients had at least one grade 3 or 4 toxicity irrespective of association with erlotinib; only four required dose modifications. The main toxicities were gastrointestinal (n = 11), dermatologic (n = 5), and metabolic (n = 4). One patient with gliomatosis cerebri who required prolonged corticosteroids died of septic shock associated with pancreatitis. Conclusion: Although therapy with erlotinib was mostly well-tolerated, it did not change the poor outcome of our patients. Our results showed that erlotinib is not a promising medication in the treatment of children with intracranial AA and GBM. PMID:24744992

  7. Targeting the PI3K/AKT/mTOR pathway overcomes the stimulating effect of dabrafenib on the invasive behavior of melanoma cells with acquired resistance to the BRAF inhibitor.

    PubMed

    Caporali, Simona; Alvino, Ester; Lacal, Pedro Miguel; Levati, Lauretta; Giurato, Giorgio; Memoli, Domenico; Caprini, Elisabetta; Antonini Cappellini, Gian Carlo; D'Atri, Stefania

    2016-09-01

    BRAF inhibitors (BRAFi) have proven clinical benefits in patients with BRAF-mutant melanoma. However, acquired resistance eventually arises. The effects of BRAFi on melanoma cell proliferation and survival have been extensively studied, and several mechanisms involved in acquired resistance to the growth suppressive activity of these drugs have been identified. Much less is known about the impact of BRAFi, and in particular of dabrafenib, on the invasive potential of melanoma cells. In the present study, the BRAF-mutant human melanoma cell line A375 and its dabrafenib-resistant subline A375R were analyzed for invasive capacity, expression of vascular endothelial growth factor receptor (VEGFR)-2, and secretion of VEGF-A and matrix metalloproteinase (MMP)-9, under basal conditions or in response to dabrafenib. The consequences of inhibiting the PI3K/AKT/mTOR pathway on A375R cell responses to dabrafenib were also evaluated. We found that A375R cells were more invasive and secreted higher levels of VEGF-A and MMP-9 as compared with A375 cells. Dabrafenib reduced invasiveness, VEGFR-2 expression and VEGF-A secretion in A375 cells, whereas it increased invasiveness, VEGF-A and MMP-9 release in A375R cells. In these latter cells, the stimulating effects of dabrafenib on the invasive capacity were markedly impaired by the anti-VEGF‑A antibody bevacizumab, or by AKT1 silencing. A375R cells were not cross-resistant to the PI3K/mTOR inhibitor GSK2126458A. Moreover, this inhibitor given in combination with dabrafenib efficiently counteracted the stimulating effects of the BRAFi on invasiveness and VEGF-A and MMP-9 secretion. Our data demonstrate that melanoma cells with acquired resistance to dabrafenib possess a more invasive phenotype which is further stimulated by exposure to the drug. Substantial evidence indicates that continuing BRAFi therapy beyond progression produces a clinical benefit. Our results suggest that after the development of resistance, a regimen

  8. Phase I Trial of Consolidative Radiotherapy with Concurrent Bevacizumab, Erlotinib and Capecitabine for Unresectable Pancreatic Cancer

    PubMed Central

    Gunther, Jillian R.; Munsell, Mark F.; Das, Prajnan; Minsky, Bruce D.; Delclos, Marc E.; Chatterjee, Deyali; Wang, Huamin; Clemons, Marilyn; George, Geena; Singh, Pankaj K.; Katz, Matthew H.; Fleming, Jason B.; Javle, Milind M.; Wolff, Robert A.; Varadhachary, Gauri R.; Crane, Christopher H.; Krishnan, Sunil

    2016-01-01

    Purpose To determine the safety, tolerability and maximum tolerated dose (MTD) of addition of erlotinib to bevacizumab and capecitabine-based definitive chemoradiation (CRT) in unresectable pancreatic cancer. Methods Seventeen patients with CT-staged, biopsy-proven unresectable pancreatic cancer were enrolled between 3/2008 and 10/2010. Prior chemotherapy was permitted. Two patients each were enrolled at dose levels (DLs) 1–4 and 9 patients at DL 5. All patients received 50.4 Gy (GTV only) in 28 fractions with concurrent capecitabine, bevacizumab and erlotinib. Dose of each drug was escalated in 5 DLs using the continual reassessment method. Bevacizumab was escalated from 5mg/Kg q2weeks (DLs 1–4) to 10mg/Kg q2weeks (DL 5); daily erlotinib from 100mg/day (DLs 1–2) to 150 mg/Kg (DLs 3–5); and capecitabine from 400mg/m2 twice daily on days of radiation (DL 1) to 650mg/m2 (DLs 2–3) to 825 mg/m2 (DLs 4–5). Reassessment for potential resection was performed 6–8 weeks later. Results Sixteen patients received gemcitabine-based chemotherapy prior to CRT. With a median clinical follow-up of 10 months, no grade 3 toxicities were observed in DLs 1–4. Three (33%) patients at DL 5 developed a grade 3 acute toxicity (2 diarrhea, 1 rash). No grade 4 or 5 toxicities were seen. DL 4 was selected as the MTD; therefore, the recommended doses in combination with radiation are: bevacizumab, 5mg/Kg q2weeks; erlotinib, 150 mg/Kg daily; and capecitabine, 825mg/m2 BID. Median survival was 17.4 months. Of the five patients who underwent resection, 4 were originally deemed locally advanced and 1 was borderline resectable. Three patients had excellent pathological response (2 complete response and 20% viable tumor) at surgery, and the 2 patients with complete response are still alive at 61 and 67 months of follow up with no local or distant failures. Conclusions This chemoradiation regimen at the recommended dose levels is safe and tolerable for patients with unresectable

  9. Clinical, Paraclinical, and Antimicrobial Resistance Features of Community-Acquired Acute Bacterial Meningitis at a Large Infectious Diseases Ward in Tehran, Iran.

    PubMed

    Heydari, Behrooz; Khalili, Hossein; Karimzadeh, Iman; Emadi-Kochak, Hamid

    2016-01-01

    In this study demographic, clinical, paraclinical, microbiological, and therapeutic features of patients with community-acquired acute bacterial meningitis admitted to a referral center for infectious diseases in Iran, have been evaluated. Medical records of adult (> 18 years) individuals with confirmed diagnosis of community-acquired bacterial meningitis during a 4-year period were retrospectively reviewed. All required data were obtained from patients' medical charts. Available findings about antimicrobial susceptibility of isolated bacteria from CSF and/or blood were also collected. Kirby-Bauer disc diffusion method was used to determine their antimicrobial susceptibility profile. Details of medical management including antibiotic regimen, duration, patients' outcome, and possible sequelae of meningitis were recorded. The most commonly isolated microorganism from CSF or blood of patients was Streptococcus pneumonia (33.33%) followed by Neisseria meningitidis (27.78%) and Haemophilus influenza (16.67%). The most common antimicrobial regimen was ceftriaxone plus vancomycin (69.44%) followed by ceftriaxone plus vancomycin plus ampicillin (11.11%). Neurological sequelae of meningitis including cranial nerve palsy, deafness, and hemiparesis were identified in 4 (11.11%), 2 (5.56%), and 1 (2.78%) subjects, respectively. Regarding mortality, only 3 (8.33%) patients died from bacterial meningitis and the remaining 33 individuals discharged from the hospital. In conclusion, findings of the current study demonstrated that the mean incidence of acute bacterial meningitis in a referral infectious diseases ward in Iran was 9 episodes per year. The majority cases of community-acquired acute bacterial meningitis admitted to our center had negative CSF culture and classic triad of meningitis was absent in them. PMID:27610176

  10. Clinical, Paraclinical, and Antimicrobial Resistance Features of Community-Acquired Acute Bacterial Meningitis at a Large Infectious Diseases Ward in Tehran, Iran

    PubMed Central

    Heydari, Behrooz; Khalili, Hossein; Karimzadeh, Iman; Emadi-Kochak, Hamid

    2016-01-01

    In this study demographic, clinical, paraclinical, microbiological, and therapeutic features of patients with community-acquired acute bacterial meningitis admitted to a referral center for infectious diseases in Iran, have been evaluated. Medical records of adult (> 18 years) individuals with confirmed diagnosis of community-acquired bacterial meningitis during a 4-year period were retrospectively reviewed. All required data were obtained from patients’ medical charts. Available findings about antimicrobial susceptibility of isolated bacteria from CSF and/or blood were also collected. Kirby-Bauer disc diffusion method was used to determine their antimicrobial susceptibility profile. Details of medical management including antibiotic regimen, duration, patients’ outcome, and possible sequelae of meningitis were recorded. The most commonly isolated microorganism from CSF or blood of patients was Streptococcus pneumonia (33.33%) followed by Neisseria meningitidis (27.78%) and Haemophilus influenza (16.67%). The most common antimicrobial regimen was ceftriaxone plus vancomycin (69.44%) followed by ceftriaxone plus vancomycin plus ampicillin (11.11%). Neurological sequelae of meningitis including cranial nerve palsy, deafness, and hemiparesis were identified in 4 (11.11%), 2 (5.56%), and 1 (2.78%) subjects, respectively. Regarding mortality, only 3 (8.33%) patients died from bacterial meningitis and the remaining 33 individuals discharged from the hospital. In conclusion, findings of the current study demonstrated that the mean incidence of acute bacterial meningitis in a referral infectious diseases ward in Iran was 9 episodes per year. The majority cases of community-acquired acute bacterial meningitis admitted to our center had negative CSF culture and classic triad of meningitis was absent in them. PMID:27610176

  11. Acquired resistance to zoledronic acid and the parallel acquisition of an aggressive phenotype are mediated by p38-MAP kinase activation in prostate cancer cells

    PubMed Central

    Milone, M R; Pucci, B; Bruzzese, F; Carbone, C; Piro, G; Costantini, S; Capone, F; Leone, A; Di Gennaro, E; Caraglia, M; Budillon, A

    2013-01-01

    The nitrogen-containing bisphosphonates (N-BP) zoledronic acid (ZOL) inhibits osteoclast-mediated bone resorption, and it is used to prevent skeletal complications from bone metastases. ZOL has also demonstrated anticancer activities in preclinical models and, recently, in cancer patients, highlighting the interest in determining eventual mechanisms of resistance against this agent. In our study, we selected and characterised a resistant subline of prostate cancer (PCa) cells to better understand the mechanisms, by which tumour cells can escape the antitumour effect of ZOL. DU145R80-resistant cells were selected in about 5 months using stepwise increasing concentrations of ZOL from DU145 parental cells. DU145R80 cells showed a resistance index value of 5.5 and cross-resistance to another N-BP, pamidronate, but not to the non-nitrogen containing BP clodronate. Notably, compared with DU145 parental cells, DU145R80 developed resistance to apoptosis and anoikis, as well as overexpressed the anti-apoptotic protein Bcl-2 and oncoprotein c-Myc. Moreover, DU145R80 cells underwent epithelial to mesenchymal transition (EMT) and showed increased expression of the metalloproteases MMP-2/9, as well as increased invading capability. Interestingly, compared with DU145, DU145R80 cells also increased the gene expression and protein secretion of VEGF and the cytokines Eotaxin-1 and IL-12. At the molecular level, DU145R80 cells showed strong activation of the p38-MAPK-dependent survival pathway compared with parental sensitive cells. Moreover, using the p38-inhibitor SB203580, we completely reversed the resistance to ZOL, as well as EMT marker expression and invasion. Furthermore, SB203580 treatment reduced the expression of VEGF, Eotaxin-1, IL-12, MMP-9, Bcl-2 and c-Myc. Thus, for the first time, we demonstrate that the p38-MAPK pathway can be activated under continuous extensive exposure to ZOL in PCa cells and that the p38-MAPK pathway has a critical role in the induction of

  12. Applying the ResFinder and VirulenceFinder web-services for easy identification of acquired antibiotic resistance and E. coli virulence genes in bacteriophage and prophage nucleotide sequences.

    PubMed

    Kleinheinz, Kortine Annina; Joensen, Katrine Grimstrup; Larsen, Mette Voldby

    2014-01-01

    Extensive research is currently being conducted on the use of bacteriophages for applications in human medicine, agriculture and food manufacturing. However, phages are important vehicles of horisontal gene transfer and play a significant role in bacterial evolution. As a result, concern has been raised that this increased use and dissemination of phages could result in spread of deleterious genes, e.g., antibiotic resistance and virulence genes. Meanwhile, in the wake of the genomic era, several tools have been developed for characterization of bacterial genomes. Here we describe how two of these tools, ResFinder and VirulenceFinder, can be used to identify acquired antibiotic resistance and virulence genes in phage genomes of interest. The general applicability of the tools is demonstrated on data sets of 1,642 phage genomes and 1,442 predicted prophages.

  13. Annexin A1 is involved in the acquisition and maintenance of a stem cell-like/aggressive phenotype in prostate cancer cells with acquired resistance to zoledronic acid.

    PubMed

    Bizzarro, Valentina; Belvedere, Raffaella; Milone, Maria Rita; Pucci, Biagio; Lombardi, Rita; Bruzzese, Francesca; Popolo, Ada; Parente, Luca; Budillon, Alfredo; Petrella, Antonello

    2015-09-22

    In this study, we have characterized the role of annexin A1 (ANXA1) in the acquisition and maintenance of stem-like/aggressive features in prostate cancer (PCa) cells comparing zoledronic acid (ZA)-resistant DU145R80 with their parental DU145 cells. ANXA1 is over-expressed in DU145R80 cells and its down-regulation abolishes their resistance to ZA. Moreover, ANXA1 induces DU145 and DU145R80 invasiveness acting through formyl peptide receptors (FPRs). Also, ANXA1 knockdown is able to inhibit epithelial to mesenchymal transition (EMT) and to reduce focal adhesion kinase (FAK) and metalloproteases (MMP)-2/9 expression in PCa cells. DU145R80 show a cancer stem cell (CSC)-like signature with a high expression of CSC markers including CD44, CD133, NANOG, Snail, Oct4 and ALDH7A1 and CSC-related genes as STAT3. Interestingly, ANXA1 knockdown induces these cells to revert from a putative prostate CSC to a more differentiated phenotype resembling DU145 PCa cell signature. Similar results are obtained concerning some drug resistance-related genes such as ATP Binding Cassette G2 (ABCG2) and Lung Resistant Protein (LRP). Our study provides new insights on the role of ANXA1 protein in PCa onset and progression. PMID:26312765

  14. Development and in vitro evaluation of core-shell type lipid-polymer hybrid nanoparticles for the delivery of erlotinib in non-small cell lung cancer.

    PubMed

    Mandal, Bivash; Mittal, Nivesh K; Balabathula, Pavan; Thoma, Laura A; Wood, George C

    2016-01-01

    Core-shell type lipid-polymer hybrid nanoparticles (CSLPHNPs) have emerged as a multifunctional drug delivery platform. The delivery system combines mechanical advantages of polymeric core and biomimetic advantages of the phospholipid shell into a single platform. We report the development of CSLPHNPs composed of the lipid monolayer shell and the biodegradable polymeric core for the delivery of erlotinib, an anticancer drug, clinically used to treat non-small cell lung cancer (NSCLC). Erlotinib loaded CSLPHNPs were prepared by previously reported single-step sonication method using polycaprolactone (PCL) as the biodegradable polymeric core and phospholipid-shell composed of hydrogenated soy phosphatidylcholine (HSPC) and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)-2000 (DSPE-PEG2000). Erlotinib loaded CSLPHNPs were characterized for physicochemical properties including mean particle size, polydispersity index (PDI), zeta potential, morphology, thermal and infrared spectral analysis, drug loading, in vitro drug release, in vitro serum stability, and storage stability. The effect of critical formulation and process variables on two critical quality attributes (mean particle size and drug entrapment efficiency) of erlotinib loaded CSLPHNPs was studied and optimized. In addition, in vitro cellular uptake, luminescent cell viability assay and colony formation assay were performed to evaluate efficacy of erlotinib loaded CSLPHNPs in A549 cells, a human lung adenocarcinoma cell line. Optimized erlotinib loaded CSLPHNPs were prepared with mean particle size of about 170nm, PDI<0.2, drug entrapment efficiency of about 66% with good serum and storage stability. The evaluation of in vitro cellular efficacy results indicated enhanced uptake and efficacy of erlotinib loaded CSLPHNPs compared to erlotinib solution in A549 cells. Therefore, CSLPHNPs could be a potential delivery system for erlotinib in the therapy of NSCLC.

  15. Celecoxib-erlotinib combination delays growth and inhibits angiogenesis in EGFR-mutated lung cancer

    PubMed Central

    Li, Yi Xiao; Wang, Jia Le; Gao, Meng; Tang, Hao; Gui, Rong; Fu, Yun Feng

    2016-01-01

    Combination treatment for non-small cell lung cancer (NSCLC) is becoming more popular due to the anticipation that it may be more effective than single drug treatment. In addition, there are efforts to genetically screen patients for specific mutations in light of attempting to administer specific anticancer agents that are most effective. In this study, we evaluate the anticancer and anti-angiogenic effects of low dose celecoxib-erlotinib combination in NSCLC in vitro and in vivo. In NSCLC cells harboring epidermal growth factor receptor (EGFR) mutations, combination celecoxib-erlotinib treatment led to synergistic cell death, but there was minimal efficacy in NSCLC cells with wild-type EGFR. In xenograft models, combination treatment also demonstrated greater inhibition of tumor growth compared to individual treatment. The anti-tumor effect observed was secondary to the targeting of angiogenesis, evidenced by decreased vascular endothelial growth factor A (VEGFA) levels and decreased levels of CD31 and microvessel density. Combination treatment targets angiogenesis through the modulation of of the PI3K/AKT and ERK/Raf1-1 pathway in NSCLC with EGFR exon 19 deletions. These findings may have significant clinical implications in patients with tumors harboring EGFR exon 19 deletions as they may be particularly sensitive to this regimen. PMID:27508092

  16. Celecoxib-erlotinib combination delays growth and inhibits angiogenesis in EGFR-mutated lung cancer.

    PubMed

    Li, Yi Xiao; Wang, Jia Le; Gao, Meng; Tang, Hao; Gui, Rong; Fu, Yun Feng

    2016-01-01

    Combination treatment for non-small cell lung cancer (NSCLC) is becoming more popular due to the anticipation that it may be more effective than single drug treatment. In addition, there are efforts to genetically screen patients for specific mutations in light of attempting to administer specific anticancer agents that are most effective. In this study, we evaluate the anticancer and anti-angiogenic effects of low dose celecoxib-erlotinib combination in NSCLC in vitro and in vivo. In NSCLC cells harboring epidermal growth factor receptor (EGFR) mutations, combination celecoxib-erlotinib treatment led to synergistic cell death, but there was minimal efficacy in NSCLC cells with wild-type EGFR. In xenograft models, combination treatment also demonstrated greater inhibition of tumor growth compared to individual treatment. The anti-tumor effect observed was secondary to the targeting of angiogenesis, evidenced by decreased vascular endothelial growth factor A (VEGFA) levels and decreased levels of CD31 and microvessel density. Combination treatment targets angiogenesis through the modulation of of the PI3K/AKT and ERK/Raf1-1 pathway in NSCLC with EGFR exon 19 deletions. These findings may have significant clinical implications in patients with tumors harboring EGFR exon 19 deletions as they may be particularly sensitive to this regimen. PMID:27508092

  17. The SATURN trial: the value of maintenance erlotinib in patients with non-small-cell lung cancer.

    PubMed

    Neal, Joel W

    2010-12-01

    The first-line treatment of advanced non-small-cell lung cancer (NSCLC) generally consists of a maximum of six cycles of platinum-based doublet chemotherapy followed by surveillance for disease progression. Recently, the strategy of starting second-line treatment immediately following the completion of chemotherapy, known as 'maintenance' chemotherapy, has been investigated. The use of maintenance pemetrexed improves both progression-free and overall survival, while the use of maintenance docetaxel did not significantly improve overall survival. The Sequential Tarceva in Unresectable NSCLC (SATURN) study investigated the use of maintenance erlotinib following the completion of first-line chemotherapy. It demonstrated a significant improvement in overall survival from 11.1 months in the placebo group to 12.3 months in patients receiving maintenance erlotinib, with the important caveat that only 21% of patients in the placebo group ever received erlotinib. A subset of patients whose tumors had EGF receptor mutations had a higher magnitude of benefit from maintenance treatment. Therefore, maintenance erlotinib should be considered in the treatment of patients with NSCLC.

  18. A phase I trial of erlotinib in patients with nonprogressive glioblastoma multiforme postradiation therapy, and recurrent malignant gliomas and meningiomas†

    PubMed Central

    Raizer, Jeffrey J.; Abrey, Lauren E.; Lassman, Andrew B.; Chang, Susan M.; Lamborn, Kathleen R.; Kuhn, John G.; Yung, W.K. Alfred; Gilbert, Mark R.; Aldape, Kenneth D.; Wen, Patrick Y.; Fine, Howard A.; Mehta, Minesh; DeAngelis, Lisa M.; Lieberman, Frank; Cloughesy, Timothy F.; Robins, H. Ian; Dancey, Janet; Prados, Michael D.

    2010-01-01

    The objective of this phase I study was to determine the maximal tolerated dose (MTD) of erlotinib in patients with recurrent malignant gliomas (MGs) or recurrent meningiomas on enzyme-inducing antiepileptic drugs (EIAEDs). Dose escalation was by a standard 3 × 3 design. The initial starting dose of erlotinib was 150 mg daily. If no dose-limiting toxicity (DLT) was observed, then dose escalation occurs as follows: 200 mg/day, 275 mg/day, and then increased in 125 mg increments until the MTD was reached. The MTD was defined as the dose where ≤1 of 6 patients experienced a DLT and the dose above had 2 or more DLTs. The MTD was 650 mg/day; the observed DLTs were grade 3 rash in 2 patients at 775 mg/day. Pharmacokinetic analysis showed a significant influence of EIAEDs on the metabolism of erlotinib when compared with our phase II data published separately. Primary toxicities were rash and diarrhea. The MTD of erlotinib in patients receiving EIAEDs is substantially higher than the standard dose of 150 mg. This has important implications for further development of this drug in the treatment of MG as well as the optimal management of patients with other malignancies such as NSCLC who are on enzyme-inducing drugs. PMID:20150371

  19. Inhibition of EGFR Tyrosine Kinase by Erlotinib Prevents Sclerodermatous Graft-Versus-Host Disease in a Mouse Model.

    PubMed

    Morin, Florence; Kavian, Niloufar; Marut, Wioleta; Chéreau, Christiane; Cerles, Olivier; Grange, Philippe; Weill, Bernard; Nicco, Carole; Batteux, Frédéric

    2015-10-01

    Chronic graft-versus-host disease (GVHD) follows allogeneic hematopoietic stem cell transplantation. It results from alloreactive processes induced by minor histocompatibility antigen incompatibilities leading to the activation of CD4 T cells and the development of fibrosis and inflammation of the skin and visceral organs and autoimmunity that resemble systemic sclerosis. EGFR is a ubiquitous cell receptor deeply involved in cell proliferation, differentiation, and motility. EGFR has recently been implicated in autoimmune and fibrotic diseases. Therefore, we tested whether Erlotinib, an EGFR tyrosine kinase inhibitor, can prevent sclerodermatous GVHD (Scl-GVHD). Scl-GVHD was induced in BALB/c mice by B10.D2 bone marrow and spleen cell transplantation. Transplanted mice displayed severe clinical symptoms including alopecia, fibrosis of the skin and visceral organs, vasculitis, and diarrhea. The symptoms were reversed in mice treated with Erlotinib. These beneficial effects were mediated by the decreased production of activated/memory CD4(+) T cells and the reduction in T-cell infiltration of the skin and visceral organs along with a decrease in IFN-γ and IL-13 production and autoimmune B-cell activation. The improvement provided by Erlotinib in the mouse model of Scl-GVHD supplies a rationale for the evaluation of Erlotinib in the management of patients affected by chronic GVHD.

  20. Comparative Prevalence of Antimicrobial Resistance in Community-Acquired Urinary Tract Infection Cases from Representative States of Northern and Southern India

    PubMed Central

    Gupta, Shivani; Padmavathi, DV

    2014-01-01

    Context: Urinary tract infections (UTIs) are amongst the most common infections described in outpatient settings. Increased antimicrobial resistance (AMR) of urinary tract pathogens is a matter of global public health concern. Treatment of UTI depends on both prevalence and antimicrobial resistance (AMR) of causative bacteria at any specific geographical location. Aim: This study was undertaken to compare the prevalence of uropathogens and their AMR profile in two different geographical parts of India. Materials and Methods: Clean-catch mid-stream urine samples were collected from adult patients, bacterial flora isolated from human urine was evaluated for antimicrobial susceptibility profile using Kirby Bauer’s disc diffusion method among patients from Hyderabad (Southern India), Rajasthan and Punjab (Northern India). The data were analysed using Chi-square (χ2) test, confidence interval (CI), odds ratio (OR) analysis and p-value using SPSS 16 software. Results: Escherichia coli (55.1%) were the most prevalent isolates followed by Enterococcus faecalis (15.8%). Amikacin was the most active antimicrobial agents which showed low resistance rate of 14%. The present study revealed the geographical difference in prevalence of uropathogens with Klebsiella pneumoniae being the second most common uropathogen followed by E. faecalis in the states from northern India while no K. pneumoniae was seen in samples from southern India but E. faecalis was the second most prevalent organism. Conclusion: Therefore, development of regional surveillance programs is highly recommended for implementation of national CA-UTI guidelines in Indian settings. PMID:25386432

  1. Nuclear factor-ĸB plays a critical role in both intrinsic and acquired resistance against endocrine therapy in human breast cancer cells.

    PubMed

    Oida, Kumiko; Matsuda, Akira; Jung, Kyungsook; Xia, Yan; Jang, Hyosun; Amagai, Yosuke; Ahn, Ginnae; Nishikawa, Sho; Ishizaka, Saori; Jensen-Jarolim, Erika; Matsuda, Hiroshi; Tanaka, Akane

    2014-01-01

    Since more than 75% of breast cancers overexpress estrogen receptors (ER), endocrine therapy targeting ER has significantly improved the survival rate. Nonetheless, breast cancer still afflicts women worldwide and the major problem behind it is resistance to endocrine therapy. We have previously shown the involvement of nuclear factor-κB (NF-κB) in neoplastic proliferation of human breast cancer cells; however, the association with the transformation of ER-positive cells remains unclear. In the current study, we focused on roles of NF-κB in the hormone dependency of breast cancers by means of ER-positive MCF-7 cells. Blocking of NF-κB signals in ER-negative cells stopped proliferation by downregulation of D-type cyclins. In contrast, the MCF-7 cells were resistant to NF-κB inhibition. Under estrogen-free conditions, the ER levels were reduced when compared with the original MCF-7 cells and the established cell subline exhibited tamoxifen resistance. Additionally, NF-κB participated in cell growth instead of the estrogen-ER axis in the subline and consequently, interfering with the NF-κB signals induced additive anticancer effects with tamoxifen. MMP-9 production responsible for cell migration, as well as the cell expansion in vivo, were suppressed by NF-κB inhibition. Therefore, we suggest that NF-κB is a master switch in both ER-positive and ER-negative breast cancers. PMID:24531845

  2. THE FREQUENCY OF COMMUNITY-ACQUIRED METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS (CA-MRSA) AMONG SAMPLES IN INSTITUTE FOR PUBLIC HEALTH IN CANTON SARAJEVO

    PubMed Central

    Bektas, Sabaheta; Obradovic, Amina; Aljicevic, Mufida; Numanovic, Fatima; Hodzic, Dunja; Sporisevic, Lutvo

    2016-01-01

    Background: The increase in the incidence of methicillin-resistant Staphylococcus aureus (MRSA) infections lacking risk factors for exposure to the health care system has been associated with the recognition of new MRSA clones known as community-associated MRSA (CA-MRSA). These strains have been distinguished from health care-associated MRSA (HA-MRSA) strains by epidemiological, molecular and genetic means as well as by antibiotic susceptibility profile, tissue tropism and virulence traits. Objective: To assess prevalence and antibiotic susceptibility profile of CA-MRSA in Canton Sarajevo, Bosnia and Herzegovina. Results: Out of 1.905 positive Staphylococcus aureus isolates from various samples of outpatients collected during six months, 279 (14,64%) were MRSA isolates. Out of 279 MRSA samples, 133 (47,67%) were found in nasal swabs, from which 48 (36,09%) were in the age group <1 year and 39 (29,32 %) are in the age 1-5 year. Rate of the positive skin swabs was highest among the subject of age group <1 year (46 or 54,12 %) and 1-5 year (18 or 21,18 %). Predominantly antibiotic types among MRSA strains are resistant to penicillin and cefoxitin (36,90 %) and to penicillin, cefoxitin and erythromycin (61,35 %). Conclusion: Continued monitoring of epidemiology and emerging drug resistance data is critical for the effective management of these infections. PMID:27047271

  3. Efficacy of erlotinib in patients with advanced non-small cell lung cancer: a pooled analysis of randomized trials.

    PubMed

    Gao, Hui; Ding, Xin; Wei, Dong; Cheng, Peng; Su, Xiaomei; Liu, Huanyi; Aziz, Fahad; Wang, Daoyuan; Zhang, Tao

    2011-10-01

    Erlotinib is a potent reversible HER1/epidermal growth factor receptor tyrosine kinase inhibitor with single-agent activity in patients with non-small cell lung cancer. The aim of this study was to evaluate the efficacy of erlotinib for treating advanced non-small cell lung cancer by carrying out a pooled analysis of randomized controlled trials that compared erlotinib-based regimens with other agent-based regimens between January 1997 and 2011. Outcomes analyzed were objective response rate (ORR), progression-free survival (PFS), overall survival (OS), and adverse events. Fourteen trials including 7974 patients were identified. As first-line therapy was compared with chemotherapy, there was a similar ORR [OR: 0.33; 95% confidence interval (CI): 0.64-17.36; P=0.15], but decreased PFS [hazard ratio (HR): 1.55; 95% CI: 1.24-1.93; P<0.01] and OS (HR: 1.39; 95% CI: 0.99-1.94; P=0.05). As maintenance therapy was compared with placebo, erlotinib-based regimens significantly increased ORR (OR: 0.47; 95% CI: 0.31-0.70; P<0.01), prolonged PFS (HR: 0.71; 95% CI: 0.60-0.83; P<0.01), but did not improve OS (HR: 0.87; 95% CI: 0.68-1.11; P=0.22). As second/third-line therapy was compared with placebo, erlotinib-based regimens also significantly increased ORR (OR: 0.10; 95% CI: 0.02-0.41; P<0.01), prolonged PFS (HR: 0.61; 95% CI: 0.51-0.73; P<0.01), and improved OS (HR: 0.70; 95% CI: 0.58-0.84; P<0.01). However, as second/third-line therapy was compared with chemotherapy, the outcomes were similar between the two arms. When compared with PF299804, there was a decreased ORR (OR: 3.87; 95% CI: 1.27-11.81; P=0.02), and shortened PFS (HR: 0.58; 95% CI: 0.49-0.95; P=0.02). Meanwhile, erlotinib-based regimens showed no significant difference in adverse events, except for diarrhea, rash, and anemia. Erlotinib-based regimens significantly increased ORR and improved PFS as a first-line maintenance therapy or as a second/third-line therapy when compared with placebo. PMID:21808188

  4. Acquired resistance to tamoxifen is associated with loss of the type I insulin-like growth factor receptor: implications for breast cancer treatment.

    PubMed

    Fagan, Dedra H; Uselman, Ryan R; Sachdev, Deepali; Yee, Douglas

    2012-07-01

    The role of the insulin-like growth factor (IGF) system in breast cancer is well defined, and inhibitors of this pathway are currently in clinical trials. The majority of anti-IGF1R clinical trials are in estrogen receptor-positive patients who have progressed on prior endocrine therapy; early reports show no benefit for addition of IGF1R inhibitors to endocrine therapy in this setting. In this study, we examined the effectiveness of IGF1R inhibitors in vitro by generating tamoxifen-resistant (TamR) cells. We found that TamR cells had diminished levels of IGF1R with unchanged levels of insulin receptor (IR), and failed to respond to IGF-I-induced Akt activation, proliferation, and anchorage-independent growth while retaining responsiveness to both insulin and IGF-II. The IGF1R antibody dalotuzumab inhibited IGF-I-mediated Akt phosphorylation, proliferation, and anchorage-independent growth in parental cells, but had no effect on TamR cells. An IGF1R tyrosine kinase inhibitor, AEW541, with equal potency for the IGF1R and IR, inhibited IGF-I-, IGF-II-, and insulin-stimulated Akt phosphorylation, proliferation, and anchorage-independent growth in parental cells. Interestingly, AEW541 also inhibited insulin- and IGF-II-stimulated effects in TamR cells. Tamoxifen-treated xenografts also had reduced levels of IGF1R, and dalotuzumab did not enhance the effect of tamoxifen. We conclude that cells selected for tamoxifen resistance in vitro have downregulated IGF1R making antibodies directed against this receptor ineffective. Inhibition of IR may be necessary to manage tamoxifen-resistant breast cancer.

  5. Orally active microtubule-targeting agent, MPT0B271, for the treatment of human non-small cell lung cancer, alone and in combination with erlotinib.

    PubMed

    Tsai, A-C; Wang, C-Y; Liou, J-P; Pai, H-C; Hsiao, C-J; Chang, J-Y; Wang, J-C; Teng, C-M; Pan, S-L

    2014-04-10

    Microtubule-binding agents, such as taxanes and vinca alkaloids, are used in the treatment of cancer. The limitations of these treatments, such as resistance to therapy and the need for intravenous administration, have encouraged the development of new agents. MPT0B271 (N-[1-(4-Methoxy-benzenesulfonyl)-2,3-dihydro-1H-indol-7-yl]-1-oxy-isonicotinamide), an orally active microtubule-targeting agent, is a completely synthetic compound that possesses potent anticancer effects in vitro and in vivo. Tubulin polymerization assay and immunofluorescence experiment showed that MPT0B271 caused depolymerization of tubulin at both molecular and cellular levels. MPT0B271 reduced cell growth and viability at nanomolar concentrations in numerous cancer cell lines, including a multidrug-resistant cancer cell line NCI/ADR-RES. Further studies indicated that MPT0B271 is not a substrate of P-glycoprotein (P-gp), as determined by flow cytometric analysis of rhodamine-123 (Rh-123) dye efflux and the calcein acetoxymethyl ester (calcein AM) assay. MPT0B271 also caused G2/M cell-cycle arrest, accompanied by the up-regulation of cyclin B1, p-Thr161 Cdc2/p34, serine/threonine kinases polo-like kinase 1, aurora kinase A and B and the downregulation of Cdc25C and p-Tyr15 Cdc2/p34 protein levels. The appearance of MPM2 and the nuclear translocation of cyclin B1 denoted M phase arrest in MPT0B271-treated cells. Moreover, MPT0B271 induced cell apoptosis in a concentration-dependent manner; it also reduced the expression of Bcl-2, Bcl-xL, and Mcl-1 and increased the cleavage of caspase-3 and -7 and poly (ADP-ribose) polymerase (PARP). Finally, this study demonstrated that MPT0B271 in combination with erlotinib significantly inhibits the growth of the human non-small cell lung cancer A549 cells as compared with erlotinib treatment alone, both in vitro and in vivo. These findings identify MPT0B271 as a promising new tubulin-binding compound for the treatment of various cancers.

  6. Dissemination of multidrug-resistant blaCTX-M-15/IncFIIk plasmids in Klebsiella pneumoniae isolates from hospital- and community-acquired human infections in Tunisia.

    PubMed

    Mansour, Wejdene; Grami, Raoudha; Ben Haj Khalifa, Anis; Dahmen, Safia; Châtre, Pierre; Haenni, Marisa; Aouni, Mahjoub; Madec, Jean-Yves

    2015-11-01

    This study investigated the molecular features of extended-spectrum β-lactamase (ESBL)-producing Klebsiella pneumoniae from hospital- and community-acquired (HA/CA) infections in the region of Mahdia, Tunisia. Among 336 K. pneumoniae isolates recovered from both clinical contexts between July 2009 and December 2011, 49 and 15 were ESBL producers and originated from clinical and community sources, respectively. All isolates produced the CTX-M-15 enzyme. As shown by Southern blot on S1 nuclease treatment followed by pulsed-field gel electrophoresis (PFGE) gels, the blaCTX-M-15 gene was carried on IncFII (n=4), IncFIIk (n=25), IncL/M (n=4), IncK (n=1), or untypeable (n=15) plasmids in HA isolates. In CA isolates, the blaCTX-M-15 gene was carried on IncFIIk (n=6), IncFII (n=1), IncHI1 (n=1), or untypeable (n=7) plasmids. In all, 23 and 11 PFGE types were found among the HA and CA isolates. Multilocus sequence typing on representative isolates shows diverse sequence types (STs), such as ST307, ST101, ST39, ST4, ST140, ST15, and ST307 in HA isolates and ST101, ST664, and ST323 in CA isolates. This study is the first comprehensive report of ESBL plasmids in K. pneumoniae from HA and CA infections in Tunisia.

  7. The role of epithelial to mesenchymal transition in resistance to epidermal growth factor receptor tyrosine kinase inhibitors in non-small cell lung cancer.

    PubMed

    Jakobsen, Kristine Raaby; Demuth, Christina; Sorensen, Boe Sandahl; Nielsen, Anders Lade

    2016-04-01

    Inhibition of the epidermal growth factor receptor (EGFR) is an important strategy when treating non-small cell lung cancer (NSCLC) patients. However, intrinsic resistance or development of resistance during the course of treatment constitutes a major challenge. The knowledge on EGFR-directed tyrosine kinase inhibitors (TKIs) and their biological effect keeps increasing. Within the group of patients with EGFR mutations some benefit to a much higher degree than others, and for patients lacking EGFR mutations a subset experience an effect. Up to 70% of patients with EGFR mutations and 10-20% of patients without EGFR mutations initially respond to the EGFR-TKI erlotinib, but there is a severe absence of good prognostic markers. Despite initial effect, all patients acquire resistance to EGFR-TKIs. Multiple mechanisms have implications in resistance development, but much is still to be explored. Epithelial to mesenchymal transition (EMT) is a transcriptionally regulated phenotypic shift rendering cells more invasive and migratory. Within the EMT process lays a need for external or internal stimuli to give rise to changes in central signaling pathways. Expression of mesenchymal markers correlates to a bad prognosis and an inferior response to EGFR-TKIs in NSCLC due to the contribution to a resistant phenotype. A deeper understanding of the role of EMT in NSCLC and especially in EGFR-TKI resistance-development constitute one opportunity to improve the benefit of TKI treatment for the individual patient. Many scientific studies have linked the EMT process to EGFR-TKI resistance in NSCLC and our aim is to review the role of EMT in both intrinsic and acquired resistance to EGFR-TKIs.

  8. The role of epithelial to mesenchymal transition in resistance to epidermal growth factor receptor tyrosine kinase inhibitors in non-small cell lung cancer

    PubMed Central

    Jakobsen, Kristine Raaby; Demuth, Christina; Sorensen, Boe Sandahl

    2016-01-01

    Inhibition of the epidermal growth factor receptor (EGFR) is an important strategy when treating non-small cell lung cancer (NSCLC) patients. However, intrinsic resistance or development of resistance during the course of treatment constitutes a major challenge. The knowledge on EGFR-directed tyrosine kinase inhibitors (TKIs) and their biological effect keeps increasing. Within the group of patients with EGFR mutations some benefit to a much higher degree than others, and for patients lacking EGFR mutations a subset experience an effect. Up to 70% of patients with EGFR mutations and 10–20% of patients without EGFR mutations initially respond to the EGFR-TKI erlotinib, but there is a severe absence of good prognostic markers. Despite initial effect, all patients acquire resistance to EGFR-TKIs. Multiple mechanisms have implications in resistance development, but much is still to be explored. Epithelial to mesenchymal transition (EMT) is a transcriptionally regulated phenotypic shift rendering cells more invasive and migratory. Within the EMT process lays a need for external or internal stimuli to give rise to changes in central signaling pathways. Expression of mesenchymal markers correlates to a bad prognosis and an inferior response to EGFR-TKIs in NSCLC due to the contribution to a resistant phenotype. A deeper understanding of the role of EMT in NSCLC and especially in EGFR-TKI resistance-development constitute one opportunity to improve the benefit of TKI treatment for the individual patient. Many scientific studies have linked the EMT process to EGFR-TKI resistance in NSCLC and our aim is to review the role of EMT in both intrinsic and acquired resistance to EGFR-TKIs. PMID:27186512

  9. Hospital-acquired infections in a burns unit caused by an imported strain of Staphylococcus aureus with unusual multi-resistance.

    PubMed Central

    Espersen, F.; Nielsen, P. B.; Lund, K.; Sylvest, B.; Jensen, K.

    1982-01-01

    During the past year five patients from countries in the Middle East admitted to a burns unit were found to harbour a strain of Staphylococcus aureus with unusual multi-resistance to antibiotics. The admission of the first patient was followed by an outbreak of infection with this strain involving ten patients in the unit. In addition five staff members were found to be nasal carriers of the strain. As a result of this incident, the following four patients admitted to the unit were isolated on admission and the spread of their strans was thus prevented. It is recommended that patients on admission to burns units, or similar departments with patients very susceptible to infection, are isolated until their bacterial floras have been examined. PMID:7086119

  10. Application of monoclonal antibodies generated against Panton-Valentine Leukocidin (PVL-S) toxin for specific identification of community acquired methicillin resistance Staphylococcus aureus.

    PubMed

    Poojary, Niveditha Sundar; Ramlal, Shylaja; Urs, Radhika Madan; Sripathy, Murali Harishchandra; Batra, Harsh Vardhan

    2014-12-01

    Panton-Valentine Leukocidin (PVL) produced by community acquired methicillin Staphylococcus aureus (CA-MRSA) involved in skin and soft-tissue infections and necrotizing pneumonia comprised of two fractions, namely PVL S and PVL F. In the present study, three monoclonal antibodies designated as MAb1, MAb9 and MAb10 were generated against recombinant PVL-S (35kDa) protein of S. aureus. All the three MAbs specifically reacted to confirm PVL-S positive strains of S. aureus recovered from clinical samples in Western blot analysis. Similarly all the three MAbs did not show any binding to other tested 14 different pathogenic bacteria belonging to other genera and species in Western blot analysis. Furthermore, a simple dot-ELISA method was standardized for the identification of PVL-S toxin containing S. aureus strains. Initially in dot-ELISA, Protein A (Spa) of S. aureus posed background noise problems due to the non-specific binding of antibodies resulting in false positive reactions. With the addition of 10mM diethylpyrocarbonate (DEPC) along with 5% milk in PBS in the blocking step prevented this non-specific binding of Spa to mouse anti-PVL monoclonal antibodies in dot-ELISA. Once standardized, this simple dot-ELISA was evaluated with nine PVL positive strains recovered from food, environmental and clinical samples and the results were compared with PCR assay for the presence of PVL toxin genes and also with Western blot analysis. A 100% correlation was found between dot-ELISA, PCR assay and Western blot analysis. Collectively our results suggest the newly developed simple dot-ELISA system can be of immense help in providing, rapid detection of the PVL toxin containing S. aureus strains at a relatively low cost and will be a valuable tool for the reliable identification of CA-MRSA.

  11. First-line erlotinib and fixed dose-rate gemcitabine for advanced pancreatic cancer

    PubMed Central

    Vaccaro, Vanja; Bria, Emilio; Sperduti, Isabella; Gelibter, Alain; Moscetti, Luca; Mansueto, Giovanni; Ruggeri, Enzo Maria; Gamucci, Teresa; Cognetti, Francesco; Milella, Michele

    2013-01-01

    AIM: To investigate activity, toxicity, and prognostic factors for survival of erlotinib and fixed dose-rate gemcitabine (FDR-Gem) in advanced pancreatic cancer. METHODS: We designed a single-arm prospective, multicentre, open-label phase II study to evaluate the combination of erlotinib (100 mg/d, orally) and weekly FDR-Gem (1000 mg/m2, infused at 10 mg/m2 per minute) in a population of previously untreated patients with locally advanced, inoperable, or metastatic pancreatic cancer. Primary endpoint was the rate of progression-free survival at 6 mo (PFS-6); secondary endpoints were overall response rate (ORR), response duration, tolerability, overall survival (OS), and clinical benefit. Treatment was not considered to be of further interest if the PFS-6 was < 20% (p0 = 20%), while a PFS-6 > 40% would be of considerable interest (p1 = 40%); with a 5% rejection error (α = 5%) and a power of 80%, 35 fully evaluable patients with metastatic disease were required to be enrolled in order to complete the study. Analysis of prognostic factors for survival was also carried out. RESULTS: From May 2007 to September 2009, 46 patients were enrolled (male/female: 25/21; median age: 64 years; median baseline carbohydrate antigen 19-9 (CA 19-9): 897 U/mL; locally advanced/metastatic disease: 5/41). PFS-6 and median PFS were 30.4% and 14 wk (95%CI: 10-19), respectively; 1-year and median OS were 20.2% and 26 wk (95%CI: 8-43). Five patients achieved an objective response (ORR: 10.9%, 95%CI: 1.9-19.9); disease control rate was 56.5% (95%CI: 42.2-70.8); clinical benefit rate was 43.5% (95%CI: 29.1-57.8). CA 19-9 serum levels were decreased by > 25% as compared to baseline in 14/23 evaluable patients (63.6%). Treatment was well-tolerated, with skin rash being the most powerful predictor of both longer PFS (P < 0.0001) and OS (P = 0.01) at multivariate analysis (median OS for patients with or without rash: 42 wk vs 15 wk, respectively, Log-rank P = 0.03). Additional predictors of

  12. MAPK1E322K mutation increases head and neck squamous cell carcinoma sensitivity to erlotinib through enhanced secretion of amphiregulin

    PubMed Central

    Wen, Yihui; Li, Hua; Zeng, Yan; Wen, Weiping; Pendleton, Kelsey P.; Lui, Vivian W.Y.; Egloff, Ann Marie; Grandis, Jennifer R.

    2016-01-01

    Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) have not been effective in unselected head and neck squamous cell carcinoma (HNSCC) populations. We previously reported an exceptional response to a brief course of erlotinib in a patient with advanced HNSCC whose tumor harbored a MAPK1E322K somatic mutation. MAPK1E322Kwas associated with increased p-EGFR, increased EGFR downstream signaling and increased sensitivity to erlotinib. In this study, we investigated the mechanism of MAPK1E322K-mediated EGFR activation in the context of erlotinib sensitivity. We demonstrated increased AREG secretion in HNSCC cell lines harboring endogenous or exogenous MAPK1E322K compared to wild type MAPK1. We found inhibition or knockdown of MAPK1 with siRNA resulted in reduced secretion of AREG and decreased sensitivity to erlotinib in the setting of MAPK1E322K. MAPK1E322K was associated with increased AREG secretion leading to an autocrine feedback loop involving AREG, EGFR and downstream signaling. Knockdown of AREG in HNSCC cells harboring MAPK1E322K abrogated EGFR signaling and decreased sensitivity to erlotinib in vitro and in vivo. These cumulative findings implicate increased AREG secretion and EGFR activation as contributing to increased erlotinib sensitivity in MAPK1E322K HNSCC. PMID:27004400

  13. Evidence of reduced poly-B-hydroxybutyrate biosynthesis in free-living nitrogen-fixing bacteria, Azotobacter chroococcum, following acquired resistance to the fungicide captan.

    PubMed

    Miclaus, N; Vannini, C; Celano, G; Piccolo, A; Simoncini, S

    1992-08-12

    Some biological activities of Azotobacter chroococcum, strain Azcap 1, (spontaneous mutant, captan resistant up to 300 micrograms/ml) were assayed on RM medium with and without the presence of the fungicide. Comparisons were also carried out with Az. chroococcum sensitive strains Azwt, Azcan 10 and 14. The hydrolysis of captan, incorporated in agar plates of RM at 100 micrograms/ml, was rapid, since on 4-day plates, no effect was found on the strain Azwt, while on freshly prepared ones its growth was completely blocked. As for Azcap 1, grown on RM only, the behaviour was similar to that of sensitive strains, whereas when grown on captan the results of experiments showed: (i) a lag of approximately 12 h to reach the maximum nitrogen-fixing activity; (ii) delay of 12-24 h in the full consumption of glucose present in the medium, although the invertase activity did not present differences; (iii) high ATP culture content during the 50 h of the experiment; (iv) approximately 6-10-fold lower production of PHB (poly-B-hydroxybutyrate); (v) lack of typical encystment phase, for the tested 96 h and reduced viability in developing colonies on agar RM medium. In contrast, when captan was added to cultural medium at sublethal concentration, 50 micrograms/ml for sensitive strain Azwt and 200 micrograms/ml for Azcap 1, the amount of glutathione produced (to remove the fungicide toxicity) was several times higher for the former.

  14. Camel Streptococcus agalactiae populations are associated with specific disease complexes and acquired the tetracycline resistance gene tetM via a Tn916-like element

    PubMed Central

    2013-01-01

    Camels are the most valuable livestock species in the Horn of Africa and play a pivotal role in the nutritional sustainability for millions of people. Their health status is therefore of utmost importance for the people living in this region. Streptococcus agalactiae, a Group B Streptococcus (GBS), is an important camel pathogen. Here we present the first epidemiological study based on genetic and phenotypic data from African camel derived GBS. Ninety-two GBS were characterized using multilocus sequence typing (MLST), capsular polysaccharide typing and in vitro antimicrobial susceptibility testing. We analysed the GBS using Bayesian linkage, phylogenetic and minimum spanning tree analyses and compared them with human GBS from East Africa in order to investigate the level of genetic exchange between GBS populations in the region. Camel GBS sequence types (STs) were distinct from other STs reported so far. We mapped specific STs and capsular types to major disease complexes caused by GBS. Widespread resistance (34%) to tetracycline was associated with acquisition of the tetM gene that is carried on a Tn916-like element, and observed primarily among GBS isolated from mastitis. The presence of tetM within different MLST clades suggests acquisition on multiple occasions. Wound infections and mastitis in camels associated with GBS are widespread and should ideally be treated with antimicrobials other than tetracycline in East Africa. PMID:24083845

  15. Camel Streptococcus agalactiae populations are associated with specific disease complexes and acquired the tetracycline resistance gene tetM via a Tn916-like element.

    PubMed

    Fischer, Anne; Liljander, Anne; Kaspar, Heike; Muriuki, Cecilia; Fuxelius, Hans-Henrik; Bongcam-Rudloff, Erik; de Villiers, Etienne P; Huber, Charlotte A; Frey, Joachim; Daubenberger, Claudia; Bishop, Richard; Younan, Mario; Jores, Joerg

    2013-01-01

    Camels are the most valuable livestock species in the Horn of Africa and play a pivotal role in the nutritional sustainability for millions of people. Their health status is therefore of utmost importance for the people living in this region. Streptococcus agalactiae, a Group B Streptococcus (GBS), is an important camel pathogen. Here we present the first epidemiological study based on genetic and phenotypic data from African camel derived GBS. Ninety-two GBS were characterized using multilocus sequence typing (MLST), capsular polysaccharide typing and in vitro antimicrobial susceptibility testing. We analysed the GBS using Bayesian linkage, phylogenetic and minimum spanning tree analyses and compared them with human GBS from East Africa in order to investigate the level of genetic exchange between GBS populations in the region. Camel GBS sequence types (STs) were distinct from other STs reported so far. We mapped specific STs and capsular types to major disease complexes caused by GBS. Widespread resistance (34%) to tetracycline was associated with acquisition of the tetM gene that is carried on a Tn916-like element, and observed primarily among GBS isolated from mastitis. The presence of tetM within different MLST clades suggests acquisition on multiple occasions. Wound infections and mastitis in camels associated with GBS are widespread and should ideally be treated with antimicrobials other than tetracycline in East Africa.

  16. Emergence of Panton-Valentine leucocidin-positive ST8-methicillin-resistant Staphylococcus aureus (USA300 clone) in Korea causing healthcare-associated and hospital-acquired bacteraemia.

    PubMed

    Jung, J; Song, E H; Park, S Y; Lee, S-R; Park, S-J; Sung, H; Kim, M-N; Kim, S-H; Lee, S-O; Choi, S-H; Woo, J H; Kim, Y S; Chong, Y P

    2016-08-01

    Panton-Valentine leucocidin (PVL)-positive sequence type (ST)8-MRSA-SCCmec IVa (USA300) is the epidemic strain of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) in North America. USA300 is extremely rare in South Korea, and PVL-negative ST72 SCCmec type IVc is the predominant CA-MRSA clone. In a multicentre, prospective cohort study of S. aureus bacteraemia, we identified PVL-positive ST8-MRSA isolates by performing multilocus sequence typing and PCR for PVL. We analyzed the clinical characteristics of patients with PVL-positive ST8-MRSA bacteraemia, and performed SCCmec, spa, and agr typing, PCR for arginine catabolic mobile element (ACME), virulence gene profiling, and pulsed-field gel electrophoresis (PFGE). Among a total of 818 MRSA isolates, we identified ten isolates of PVL-positive ST8-MRSA (USA300) (3 from Hospital D, 4 from Hospital G, and 3 from Hospital A), all of which involved exclusively healthcare-associated (5 isolates) and hospital-acquired bacteraemia (5 isolates). This strain accounted for 8~10 % of the hospital-acquired MRSA bacteraemia in Hospitals D and G. Bacteraemia of unknown origin was the most common type of infection followed by pneumonia. All the isolates were SCCmec type IVa, spa type t008, and agr group I. Eight of the isolates harboured ACME. In a PFGE analysis, four isolates were identical to the USA300 control strain, five differed by a single band, and the remaining one differed by two bands. All the isolates were pulsed-field type USA300. This is the first report of healthcare-associated and hospital-acquired bacteraemia caused by USA300 in South Korea. USA300 seems to be an emerging hospital clone in this country. PMID:27209287

  17. Prognostic value of inflammation-based markers in patients with pancreatic cancer administered gemcitabine and erlotinib

    PubMed Central

    Lee, Jae Min; Lee, Hong Sik; Hyun, Jong Jin; Choi, Hyuk Soon; Kim, Eun Sun; Keum, Bora; Seo, Yeon Seok; Jeen, Yoon Tae; Chun, Hoon Jai; Um, Soon Ho; Kim, Chang Duck

    2016-01-01

    AIM: To evaluate the value of systemic inflammation-based markers as prognostic factors for advanced pancreatic cancer (PC). METHODS: Data from 82 patients who underwent combination chemotherapy with gemcitabine and erlotinib for PC from 2011 to 2014 were collected retrospectively. Data that included the neutrophil-to-lymphocyte ratio (NLR), the platelet-to-lymphocyte ratio, and the C-reactive protein (CRP)-to-albumin (CRP/Alb) ratio were analyzed. Kaplan-Meier curves, and univariate and multivariate Cox proportional hazards regression analyses were used to identify the prognostic factors associated with progression-free survival (PFS) and overall survival (OS). RESULTS: The univariate analysis demonstrated the prognostic value of the NLR (P = 0.049) and the CRP/Alb ratio (P = 0.047) in relation to PFS, and a positive relationship between an increase in inflammation-based markers and a poor prognosis in relation to OS. The multivariate analysis determined that an increased NLR (hazard ratio = 2.76, 95%CI: 1.33-5.75, P = 0.007) is an independent prognostic factor for poor OS. There was no association between the PLR and the patients’ prognoses in those who had received chemotherapy that comprised gemcitabine and erlotinib in combination. The Kaplan-Meier method and the log-rank test determined significantly worse outcomes in relation to PFS and OS in patients with an NLR > 5 or a CRP/Alb ratio > 5. CONCLUSION: Systemic inflammation-based markers, including increases in the NLR and the CRP/Alb ratio, may be useful for predicting PC prognoses. PMID:27559435

  18. The dominant Australian community-acquired methicillin-resistant Staphylococcus aureus clone ST93-IV [2B] is highly virulent and genetically distinct.

    PubMed

    Chua, Kyra Y L; Seemann, Torsten; Harrison, Paul F; Monagle, Shaun; Korman, Tony M; Johnson, Paul D R; Coombs, Geoffrey W; Howden, Brian O; Davies, John K; Howden, Benjamin P; Stinear, Timothy P

    2011-01-01

    Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) USA300 has spread rapidly across North America, and CA-MRSA is also increasing in Australia. However, the dominant Australian CA-MRSA strain, ST93-IV [2B] appears distantly related to USA300 despite strikingly similar clinical and epidemiological profiles. Here, we compared the virulence of a recent Australian ST93 isolate (JKD6159) to other MRSA, including USA300, and found that JKD6159 was the most virulent in a mouse skin infection model. We fully sequenced the genome of JKD6159 and confirmed that JKD6159 is a distinct clone with 7616 single nucleotide polymorphisms (SNPs) distinguishing this strain from all other S. aureus genomes. Despite its high virulence there were surprisingly few virulence determinants. However, genes encoding α-hemolysin, Panton-Valentine leukocidin (PVL) and α-type phenol soluble modulins were present. Genome comparisons revealed 32 additional CDS in JKD6159 but none appeared to encode new virulence factors, suggesting that this clone's enhanced pathogenicity could lie within subtler genome changes, such as SNPs within regulatory genes. To investigate the role of accessory genome elements in CA-MRSA epidemiology, we next sequenced three additional Australian non-ST93 CA-MRSA strains and compared them with JKD6159, 19 completed S. aureus genomes and 59 additional S. aureus genomes for which unassembled genome sequence data was publicly available (82 genomes in total). These comparisons showed that despite its distinctive genotype, JKD6159 and other CA-MRSA clones (including USA300) share a conserved repertoire of three notable accessory elements (SSCmecIV, PVL prophage, and pMW2). This study demonstrates that the genetically distinct ST93 CA-MRSA from Australia is highly virulent. Our comparisons of geographically and genetically diverse CA-MRSA genomes suggest that apparent convergent evolution in CA-MRSA may be better explained by the rapid dissemination of a

  19. BIM and mTOR expression levels predict outcome to erlotinib in EGFR-mutant non-small-cell lung cancer

    PubMed Central

    Karachaliou, Niki; Codony-Servat, Jordi; Teixidó, Cristina; Pilotto, Sara; Drozdowskyj, Ana; Codony-Servat, Carles; Giménez-Capitán, Ana; Molina-Vila, Miguel Angel; Bertrán-Alamillo, Jordi; Gervais, Radj; Massuti, Bartomeu; Morán, Teresa; Majem, Margarita; Felip, Enriqueta; Carcereny, Enric; García-Campelo, Rosario; Viteri, Santiago; González-Cao, María; Morales-Espinosa, Daniela; Verlicchi, Alberto; Crisetti, Elisabetta; Chaib, Imane; Santarpia, Mariacarmela; Luis Ramírez, José; Bosch-Barrera, Joaquim; Felipe Cardona, Andrés; de Marinis, Filippo; López-Vivanco, Guillermo; Miguel Sánchez, José; Vergnenegre, Alain; Sánchez Hernández, José Javier; Sperduti, Isabella; Bria, Emilio; Rosell, Rafael

    2015-01-01

    BIM is a proapoptotic protein that initiates apoptosis triggered by EGFR tyrosine kinase inhibitors (TKI). mTOR negatively regulates apoptosis and may influence response to EGFR TKI. We examined mRNA expression of BIM and MTOR in 57 patients with EGFR-mutant NSCLC from the EURTAC trial. Risk of mortality and disease progression was lower in patients with high BIM compared with low/intermediate BIM mRNA levels. Analysis of MTOR further divided patients with high BIM expression into two groups, with those having both high BIM and MTOR experiencing shorter overall and progression-free survival to erlotinib. Validation of our results was performed in an independent cohort of 19 patients with EGFR-mutant NSCLC treated with EGFR TKIs. In EGFR-mutant lung adenocarcinoma cell lines with high BIM expression, concomitant high mTOR expression increased IC50 of gefitinib for cell proliferation. We next sought to analyse the signalling pattern in cell lines with strong activation of mTOR and its substrate P-S6. We showed that mTOR and phosphodiesterase 4D (PDE4D) strongly correlate in resistant EGFR-mutant cancer cell lines. These data suggest that the combination of EGFR TKI with mTOR or PDE4 inhibitors could be adequate therapy for EGFR-mutant NSCLC patients with high pretreatment levels of BIM and mTOR. PMID:26639561

  20. BIM and mTOR expression levels predict outcome to erlotinib in EGFR-mutant non-small-cell lung cancer.

    PubMed

    Karachaliou, Niki; Codony-Servat, Jordi; Teixidó, Cristina; Pilotto, Sara; Drozdowskyj, Ana; Codony-Servat, Carles; Giménez-Capitán, Ana; Molina-Vila, Miguel Angel; Bertrán-Alamillo, Jordi; Gervais, Radj; Massuti, Bartomeu; Morán, Teresa; Majem, Margarita; Felip, Enriqueta; Carcereny, Enric; García-Campelo, Rosario; Viteri, Santiago; González-Cao, María; Morales-Espinosa, Daniela; Verlicchi, Alberto; Crisetti, Elisabetta; Chaib, Imane; Santarpia, Mariacarmela; Luis Ramírez, José; Bosch-Barrera, Joaquim; Felipe Cardona, Andrés; de Marinis, Filippo; López-Vivanco, Guillermo; Miguel Sánchez, José; Vergnenegre, Alain; Sánchez Hernández, José Javier; Sperduti, Isabella; Bria, Emilio; Rosell, Rafael

    2015-12-07

    BIM is a proapoptotic protein that initiates apoptosis triggered by EGFR tyrosine kinase inhibitors (TKI). mTOR negatively regulates apoptosis and may influence response to EGFR TKI. We examined mRNA expression of BIM and MTOR in 57 patients with EGFR-mutant NSCLC from the EURTAC trial. Risk of mortality and disease progression was lower in patients with high BIM compared with low/intermediate BIM mRNA levels. Analysis of MTOR further divided patients with high BIM expression into two groups, with those having both high BIM and MTOR experiencing shorter overall and progression-free survival to erlotinib. Validation of our results was performed in an independent cohort of 19 patients with EGFR-mutant NSCLC treated with EGFR TKIs. In EGFR-mutant lung adenocarcinoma cell lines with high BIM expression, concomitant high mTOR expression increased IC50 of gefitinib for cell proliferation. We next sought to analyse the signalling pattern in cell lines with strong activation of mTOR and its substrate P-S6. We showed that mTOR and phosphodiesterase 4D (PDE4D) strongly correlate in resistant EGFR-mutant cancer cell lines. These data suggest that the combination of EGFR TKI with mTOR or PDE4 inhibitors could be adequate therapy for EGFR-mutant NSCLC patients with high pretreatment levels of BIM and mTOR.

  1. Paeoniflorin Potentiates the Inhibitory Effects of Erlotinib in Pancreatic Cancer Cell Lines by Reducing ErbB3 Phosphorylation.

    PubMed

    Hao, Jian; Yang, Xue; Ding, Xiu-Li; Guo, Lei-Ming; Zhu, Cui-Hong; Ji, Wei; Zhou, Tong; Wu, Xiong-Zhi

    2016-01-01

    Blockade of the epidermal growth factor receptor (EGFR) by EGFR tyrosine kinase inhibitors is insufficient for effective anti-tumor activity because the reactivation of the ErbB3 signaling pathway significantly contributes to activating the consequent phosphoinositide 3-kinase (PI3K)/Akt signaling pathway. Combinatorial therapies including ErbB3 targeting may ameliorate tumor responses to anti-EGFR therapies. In the present study, we found that in BxPC-3 and L3.6pl cells, which highly expressed the ErbB3 receptor, significant reduction in cell viability, induction of apoptosis were observed when treated with a combination of erlotinib and PF compared to either agent alone. Moreover, in ErbB3-expressing BxPC-3, L3.6pl and S2VP10 cell lines, the inhibition of ErbB3/PI3K/Akt phosphorylation were observed when treated with PF. Most strikingly, both EGFR/MAPK/Erk and ErbB3/PI3K/Akt activitions were substantially suppressed when treated with the combination of PF and erlotinib. However, in the ErbB3-deficient cell line MIAPaCa-2, no such effects were observed with similar treatments. Most importantly, these in vitro results were replicated in nude mouse transplanted tumor models. Taken together, our findings show that PF enhances the effect of erlotinib in ErbB3-expressing pancreatic cancer cells by directly suppressing ErbB3 activation, and PF in combination with erlotinib is much more effective as an antitumor agent compared with either agent alone. PMID:27609096

  2. Paeoniflorin Potentiates the Inhibitory Effects of Erlotinib in Pancreatic Cancer Cell Lines by Reducing ErbB3 Phosphorylation

    PubMed Central

    Hao, Jian; Yang, Xue; Ding, Xiu-li; Guo, Lei-ming; Zhu, Cui-hong; Ji, Wei; Zhou, Tong; Wu, Xiong-zhi

    2016-01-01

    Blockade of the epidermal growth factor receptor (EGFR) by EGFR tyrosine kinase inhibitors is insufficient for effective anti-tumor activity because the reactivation of the ErbB3 signaling pathway significantly contributes to activating the consequent phosphoinositide 3-kinase (PI3K)/Akt signaling pathway. Combinatorial therapies including ErbB3 targeting may ameliorate tumor responses to anti-EGFR therapies. In the present study, we found that in BxPC-3 and L3.6pl cells, which highly expressed the ErbB3 receptor, significant reduction in cell viability, induction of apoptosis were observed when treated with a combination of erlotinib and PF compared to either agent alone. Moreover, in ErbB3-expressing BxPC-3, L3.6pl and S2VP10 cell lines, the inhibition of ErbB3/PI3K/Akt phosphorylation were observed when treated with PF. Most strikingly, both EGFR/MAPK/Erk and ErbB3/PI3K/Akt activitions were substantially suppressed when treated with the combination of PF and erlotinib. However, in the ErbB3-deficient cell line MIAPaCa-2, no such effects were observed with similar treatments. Most importantly, these in vitro results were replicated in nude mouse transplanted tumor models. Taken together, our findings show that PF enhances the effect of erlotinib in ErbB3-expressing pancreatic cancer cells by directly suppressing ErbB3 activation, and PF in combination with erlotinib is much more effective as an antitumor agent compared with either agent alone. PMID:27609096

  3. A phase II trial of erlotinib in patients with recurrent malignant gliomas and nonprogressive glioblastoma multiforme postradiation therapy†

    PubMed Central

    Raizer, Jeffrey J.; Abrey, Lauren E.; Lassman, Andrew B.; Chang, Susan M.; Lamborn, Kathleen R.; Kuhn, John G.; Yung, W.K. Alfred; Gilbert, Mark R.; Aldape, Kenneth A.; Wen, Patrick Y.; Fine, Howard A.; Mehta, Minesh; DeAngelis, Lisa M.; Lieberman, Frank; Cloughesy, Timothy F.; Robins, H. Ian; Dancey, Janet; Prados, Michael D.

    2010-01-01

    Patients with (a) recurrent malignant glioma (MG): glioblastoma (GBM) or recurrent anaplastic glioma (AG), and (b) nonprogressive (NP) GBM following radiation therapy (RT) were eligible. Primary objective for recurrent MG was progression-free survival at 6 months (PFS-6) and overall survival at 12 months for NP GBM post-RT. Secondary objectives for recurrent MGs were response, survival, assessment of toxicity, and pharmacokinetics (PKs). Treatment with enzyme-inducing antiepileptic drugs was not allowed. Patients received 150 mg/day erlotinib. Patients requiring surgery were treated 7 days prior to tumor removal for PK analysis and effects of erlotinib on epidermal growth factor receptor (EGFR) and intracellular signaling pathways. Ninety-six patients were evaluable (53 recurrent MG and 43 NP GBM); 5 patients were not evaluable for response. PFS-6 in recurrent GBM was 3% with a median PFS of 2 months; PFS-6 in recurrent AG was 27% with a median PFS of 2 months. Twelve-month survival was 57% in NP GBMs post-RT. Primary toxicity was dermatologic. The tissue-to-plasma ratio normalized to nanograms per gram dry weight for erlotinib and OSI-420 ranged from 25% to 44% and 30% to 59%, respectively, for pretreated surgical patients. No effect on EGFR or intratumoral signaling was seen. Patients with NP GBM post-RT who developed rash in cycle 1 had improved survival (P < .001). Single-agent activity of erlotinib is minimal for recurrent MGs and marginally beneficial following RT for NP GBM patients. Development of rash in cycle 1 correlates with survival in patients with NP GBM after RT. PMID:20150372

  4. Delay of treatment change following objective progression on first-line erlotinib in EGFR-mutant lung cancer

    PubMed Central

    Lo, Peter C.; Dahlberg, Suzanne E.; Nishino, Mizuki; Johnson, Bruce E.; Sequist, Lecia V.; Jackman, David M.; Jänne, Pasi A; Oxnard, Geoffrey R.

    2015-01-01

    Background Erlotinib is a highly active EGFR kinase inhibitor approved for first-line use in lung cancers harboring EGFR mutations. Anecdotal experience suggests this drug may provide continued disease control following objective progression of disease (PD), however this has not been systematically studied. Methods Patients with RECIST-defined PD on three prospective trials of first-line erlotinib in advanced lung cancer were studied retrospectively, comparing progression characteristics of cases with and without EGFR sensitizing mutations. Factors influencing time to treatment change (TTC), defined as the time from PD until start of a new systemic therapy or death, were studied. Rate of tumor progression was assessed by comparing tumor measurements between the PD scan and the preceding scan. Results 92 eligible patients were studied: 42 with an EGFR sensitizing mutation and 50 without. The EGFR-mutant cohort had a slower rate of progression (p = 0.003) and a longer TTC (p < 0.001). Among EGFR-mutant cancers, 28 (66%) continued single-agent erlotinib following PD and 21 (50%) were able to delay change in systemic therapy for >3 months; only 2 received local debulking therapy during that period. Multivariate analysis of EGFR-mutant cases demonstrated that longer time to progression, slower rate of progression, and lack of new extrathoracic metastases were associated with a longer TTC. Conclusions A change in systemic therapy can commonly be delayed in patients with EGFR-mutant lung cancer objectively progressing on first-line erlotinib, particularly in those with a longer time to progression, a slow rate of progression, and lack of new extrathoracic metastases. PMID:25876525

  5. 18F-FDG PET/CT for Monitoring Treatment Responses to the Epidermal Growth Factor Receptor Inhibitor Erlotinib

    PubMed Central

    Walter, Franziska; Garon, Edward B.; Reckamp, Karen L.; Figlin, Robert; Phelps, Michael E.; Weber, Wolfgang A.; Czernin, Johannes; Allen-Auerbach, Martin S.

    2016-01-01

    Response rates of unselected non–small cell lung cancer (NSCLC) patients to the epidermal growth factor receptor inhibitor erlotinib are low and range from 10% to 20%. Early response assessments are needed to avoid costs and side effects of inefficient treatments. Here we determined whether early changes in tumor uptake of 18F-FDG can predict progression-free and overall survival in NSCLC patients who are treated with erlotinib. Methods Twenty-two patients (6 men, 16 women; mean age ± SD, 64 ± 13 y) with stage III or stage IV NSCLC who received erlotinib treatment were enrolled prospectively. 18F-FDG PET/CT was performed before the initiation of treatment (n = 22), after 2 wk (n = 22), and after 78 ± 21 d (n = 11). Tumor maximum standardized uptake values were measured for a maximum of 5 lesions for each patient. Tumor responses were classified using modified PET Response Criteria in Solid Tumors (use of maximum standardized uptake values). Median overall survival by Kaplan–Meier analysis was compared between groups using a log-rank test. Results The overall median time to progression was 52 d (95% confidence interval, 47–57 d). The overall median survival time was 131 d (95% confidence interval, 0–351 d). Patients with progressive metabolic disease on early follow-up PET showed a significantly shorter time to progression (47 vs. 119 d; P < 0.001) and overall survival (87 vs. 828 d; P = 0.01) than patients classified as having stable metabolic disease or partial or complete metabolic response. Conclusion These data suggest that 18F-FDG PET/CT performed early after the start of erlotinib treatment can help to identify patients who benefit from this targeted therapy. PMID:22045706

  6. Addition of erlotinib to fluoropyrimidine-oxaliplatin-based chemotherapy with or without bevacizumab: Two sequential phase I trials.

    PubMed

    Carlomagno, Chiara; Daniele, Gennaro; Bianco, Roberto; Marciano, Roberta; Damiano, Vincenzo; Matano, Elide; Nappi, Lucia; Pepe, Stefano; DE Placido, Sabino; Tortora, Giampaolo

    2011-05-01

    The combination of EGFR inhibitors and anti-angiogenic drugs has a strong pre-clinical rationale, yet its use has produced controversial clinical results. We conducted two sequential phase I trials to evaluate the feasibility and the recommended dose of erlotinib when combined with fluoropyrimidine-oxaliplatin-based chemotherapy with or without bevacizumab. A total of 21 metastatic colorectal cancer (mCRC) patients were treated in two sequential phase I trials. In the first trial, 12 patients were treated with escalating doses of erlotinib plus FOLFOX. In the second, 9 patients were treated with escalating doses of erlotinib combined with oxaliplatin, capecitabine and bevacizumab. No MTD was reached in either of the trials. The only dose-limiting toxicities observed were neutropenia and diarrhea. No unexpected toxicities were noted. Hematological toxicity was the most frequently noted adverse event with infusional 5FU therapy, while gastrointestinal toxicity was the most common adverse event. In the second trial most patients withdrew from treatment due to toxicity, and less than half completed the therapeutic program as per protocol, mostly due to toxicity. In conclusion, the present study confirms the disappointing results of the double combination of EGFR inhibitors and anti-angiogenic drugs in mCRC patients.

  7. Severe and prolonged lymphopenia observed in patients treated with bendamustine and erlotinib for metastatic triple negative breast cancer

    PubMed Central

    Ruppert, Amy S.; Lynn, Melinda; Mrozek, Ewa; Ramaswamy, Bhuvaneswari; Lustberg, Maryam B.; Wesolowski, Robert; Ottman, Susan; Carothers, Sarah; Bingman, Anissa; Reinbolt, Raquel; Kraut, Eric H.; Shapiro, Charles L.

    2013-01-01

    Purpose Triple negative breast cancers (TNBC) frequently have high epidermal growth factor receptor (EGFR) expression and are sensitive to DNA-damaging agents. Improved therapies are needed for this aggressive malignancy. Patients and methods We performed a phase I trial of bendamustine and erlotinib, an EGFR tyrosine kinase inhibitor, in patients with metastatic TNBC, ECOG performance status ≤2, and ≤1 prior chemotherapy for metastatic disease. Each 28-day cycle included intravenous bendamustine on days 1, 2 and oral erlotinib on days 5–21 with dose escalation according to a 3 + 3 phase I study design. Dose-limiting toxicity (DLT) was determined by toxicities related to study therapy observed during cycle 1. Results Eleven patients were treated, 5 on dose level 1 and 6 on dose level 2. One patient had DLT on dose level 2. However, cumulative toxicities were observed, including grade 3/4 lymphopenia in 91 % (95 % CI 0.59–0.998) with progressively decreased CD4 counts and grade ≥3 infections in 36 % (95 % CI 0.11–0.69) of patients. Conclusions Combination therapy with bendamustine and erlotinib causes excessive toxicity with severe, prolonged lymphopenia, depressed CD4 counts, and opportunistic infections and should not be pursued further. Future trials of bendamustine combinations in TNBC patients should account for potential cumulative lymphocyte toxicity necessitating patient monitoring during and after treatment. PMID:23430121

  8. Addition of erlotinib to fluoropyrimidine-oxaliplatin-based chemotherapy with or without bevacizumab: Two sequential phase I trials

    PubMed Central

    CARLOMAGNO, CHIARA; DANIELE, GENNARO; BIANCO, ROBERTO; MARCIANO, ROBERTA; DAMIANO, VINCENZO; MATANO, ELIDE; NAPPI, LUCIA; PEPE, STEFANO; DE PLACIDO, SABINO; TORTORA, GIAMPAOLO

    2011-01-01

    The combination of EGFR inhibitors and anti-angiogenic drugs has a strong pre-clinical rationale, yet its use has produced controversial clinical results. We conducted two sequential phase I trials to evaluate the feasibility and the recommended dose of erlotinib when combined with fluoropyrimidine-oxaliplatin-based chemotherapy with or without bevacizumab. A total of 21 metastatic colorectal cancer (mCRC) patients were treated in two sequential phase I trials. In the first trial, 12 patients were treated with escalating doses of erlotinib plus FOLFOX. In the second, 9 patients were treated with escalating doses of erlotinib combined with oxaliplatin, capecitabine and bevacizumab. No MTD was reached in either of the trials. The only dose-limiting toxicities observed were neutropenia and diarrhea. No unexpected toxicities were noted. Hematological toxicity was the most frequently noted adverse event with infusional 5FU therapy, while gastrointestinal toxicity was the most common adverse event. In the second trial most patients withdrew from treatment due to toxicity, and less than half completed the therapeutic program as per protocol, mostly due to toxicity. In conclusion, the present study confirms the disappointing results of the double combination of EGFR inhibitors and anti-angiogenic drugs in mCRC patients. PMID:22977524

  9. Phase I trial of erlotinib with radiation therapy in patients with glioblastoma multiforme: Results of North Central Cancer Treatment Group protocol N0177

    SciTech Connect

    Krishnan, Sunil . E-mail: skrishnan@mdanderson.org; Brown, Paul D.; Ballman, Karla V.; Fiveash, John B.; Uhm, Joon H.; Giannini, Caterina; Jaeckle, Kurt A.; Geoffroy, Francois J.; Nabors, L. Burt; Buckner, Jan C.

    2006-07-15

    Purpose: To evaluate the toxicity and maximum tolerated dose (MTD) of erlotinib plus radiation therapy (RT) in patients with glioblastoma multiforme (GBM) in a multicenter phase I trial. Methods and Materials: Patients were stratified on the basis of the use of enzyme-inducing anticonvulsants (EIACs). After resection or biopsy, patients were treated with erlotinib for 1 week before concurrent erlotinib and 6 weeks (60 Gy) of RT and maintained on erlotinib until progression. The erlotinib dose was escalated in cohorts of 3 starting at 100 mg/day. Results: Twenty patients were enrolled and 19 were evaluable for the MTD and efficacy endpoints. Of these patients, 14 were males and 5 were females, with a median age of 54 years. Seven had undergone biopsy only, 5 had subtotal resections, and 7 had gross total resections. The highest dose level was 150 mg/day erlotinib for patients not on EIACs (Group 1) and 200 mg/day for patients on EIACs (Group 2). MTD was not reached in either group. In Group 1 at 100 mg (n = 6) and at 150 mg (n = 4), only 1 dose-limiting toxicity (DLT) occurred (stomatitis at 100 mg). No DLTs have occurred in Group 2 at 100 mg (n = 3), 150 mg (n = 3), and 200 mg (n = 3). With a median follow-up of 52 weeks, progression was documented in 16 patients and 13 deaths occurred. Median time to progression was 26 weeks, and median survival was 55 weeks. Conclusion: Toxicity is acceptable at the current doses of erlotinib plus RT. The study was modified to include concurrent and adjuvant temozolomide, and accrual is in progress.

  10. Randomized Phase II Trial of Erlotinib Alone or With Carboplatin and Paclitaxel in Patients Who Were Never or Light Former Smokers With Advanced Lung Adenocarcinoma: CALGB 30406 Trial

    PubMed Central

    Jänne, Pasi A.; Wang, Xiaofei; Socinski, Mark A.; Crawford, Jeffrey; Stinchcombe, Thomas E.; Gu, Lin; Capelletti, Marzia; Edelman, Martin J.; Villalona-Calero, Miguel A.; Kratzke, Robert; Vokes, Everett E.; Miller, Vincent A.

    2012-01-01

    Purpose Erlotinib is clinically effective in patients with non–small-cell lung cancer (NSCLC) who have adenocarcinoma, are never or limited former smokers, or have EGFR mutant tumors. We investigated the efficacy of erlotinib alone or in combination with chemotherapy in patients with these characteristics. Patients and Methods Patients with advanced NSCLC (adenocarcinoma) who were epidermal growth factor receptor tyrosine kinase inhibitor and chemotherapy naive never or light former smokers (smokers of > 100 cigarettes and ≤ 10 pack years and quit ≥ 1 year ago) were randomly assigned to continuous erlotinib or in combination with carboplatin and paclitaxel (ECP) for six cycles followed by erlotinib alone. The primary end point was progression-free survival (PFS). Tissue collection was mandatory. Results PFS was similar (5.0 v 6.6 months; P = .1988) in patients randomly assigned to erlotinib alone (arm A; n = 81) or to ECP (arm B; n = 100). EGFR mutation analysis was possible in 91% (164 of 181) of patients, and EGFR mutations were detected in 40% (51 of 128) of never smokers and in 42% (15 of 36) of light former smokers. In arm A, response rate (70% v 9%), PFS (14.1 v 2.6 months), and overall survival (OS; 31.3 v 18.1 month) favored EGFR-mutant patients. In arm B, response rate (73% v 30%), PFS (17.2 v 4.8 months), and OS (38.1 v 14.4 months) favored EGFR-mutant patients. Incidence of grades 3 to 4 hematologic (2% v 49%; P < .001) and nonhematologic (24% v 52%; P < .001) toxicity was greater in patients treated with ECP. Conclusion Erlotinib and erlotinib plus chemotherapy have similar efficacy in clinically selected populations of patients with advanced NSCLC. EGFR mutations identify patients most likely to benefit. PMID:22547605

  11. The impact of autophagy on cell death modalities in CRL-5876 lung adenocarcinoma cells after their exposure to γ-rays and/or erlotinib.

    PubMed

    Keta, Otilija; Bulat, Tanja; Golić, Igor; Incerti, Sebastien; Korać, Aleksandra; Petrović, Ivan; Ristić-Fira, Aleksandra

    2016-04-01

    In most patients with lung cancer radiation treatment is used either as single agent or in combination with radiosensitizing drugs. However, the mechanisms underlying combined therapy and its impact on different modes of cell death have not yet been fully elucidated. We aimed to examine effects of single and combined treatments with γ-rays and erlotinib on radioresistant CRL-5876 human lung adenocarcinoma cells with particular emphasis on cell death. CRL-5876 cells were treated with γ-rays and/or erlotinib and changes in cell cycle, DNA repair dynamics, ultrastructure, nuclear morphology and protein expression were monitored at different time points. To reveal the relationship between types of cell death that arise after these treatments, autophagy was blocked with chloroquine. We found that higher dose of γ-rays causes G2/M arrest while adding of erlotinib to this treatment decreases the number of cells in S phase. Impact of erlotinib on kinetics of disappearance of irradiation-induced DNA double strand breaks is reflected in the increase of residual γ-H2AX foci after 24 h. γ-rays provoke cytoprotective autophagy which precedes development of senescence. Erlotinib predominantly induces apoptosis and enlarges the number of apoptotic cells in the irradiated CRL-5876 cells. Chloroquine improved cytotoxicity induced by radiation and erlotinib, increased apoptosis and decreased senescence in the CRL-5876 cells. The results obtained on CRL-5876 cells indicate significant radiosensitizing effect of erlotinib and suggest that chloroquine in the combination with the above treatments may have an additional antitumor effect in lung adenocarcinoma.

  12. Initial Results of a Phase I Dose-Escalation Trial of Concurrent and Maintenance Erlotinib and Reirradiation for Recurrent and New Primary Head-and-Neck Cancer

    SciTech Connect

    Rusthoven, Kyle E.; Feigenberg, Steven J.; Raben, David; Kane, Madeleine; Song, John I.; Nicolaou, Nicos; Mehra, Ranee; Burtness, Barbara; Ridge, John; Swing, Robyn; Lango, Miriam; Cohen, Roger; Jimeno, Antonio; Chen Changhu

    2010-11-15

    Purpose: To present the first report of a Phase I trial evaluating concurrent and maintenance erlotinib and reirradiation in patients with recurrent or secondary primary head-and-neck cancer (HNC). Methods and Materials: Patients with recurrent or new primary HNC with an interval of at least 6 months since prior radiation were eligible. Patients were treated in 3 sequential cohorts: Cohort I, 100 mg of erlotinib daily with reirradiation at 61.6 Gy in 28 fractions; Cohort II, 150 mg of erlotinib with 61.6 Gy in 28 fractions; and Cohort III, 150 mg of erlotinib