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Sample records for bcl-2 independent pathways

  1. Bcl2 at the endoplasmic reticulum protects against a Bax/Bak-independent paraptosis-like cell death pathway initiated via p20Bap31.

    PubMed

    Heath-Engel, Hannah M; Wang, Bing; Shore, Gordon C

    2012-02-01

    Bap31 is an integral ER membrane protein which functions as an escort factor in the sorting of newly synthesized membrane proteins within the endoplasmic reticulum (ER). During apoptosis signaling, Bap31 is subject to early cleavage by initiator caspase-8. The resulting p20Bap31 (p20) fragment has been shown to initiate proapoptotic ER-mitochondria Ca2+ transmission, and to exert dominant negative (DN) effects on ER protein trafficking. We now report that ectopic expression of p20 in E1A/DNp53-transformed baby mouse kidney epithelial cells initiates a non-apoptotic form of cell death with paraptosis-like morphology. This pathway was characterized by an early rise in ER Ca2+ stores and massive dilation of the ER/nuclear envelope, dependent on intact ER Ca2+ stores. Ablation of the Bax/Bak genes had no effect on these ER/nuclear envelope transformations, and delayed but did not prevent cell death. ER-restricted expression of Bcl2 in the absence of Bax/Bak, however, delayed both ER/nuclear envelope dilation and cell death. This prosurvival role of Bcl2 at the ER thus extended beyond inhibition of Bax/Bak, and correlated with its ability to lower ER Ca2+ stores. Furthermore, these results indicate that ER restricted Bcl2 is capable of antagonizing not only apoptosis, but also a non-apoptotic, Bax/Bak independent, paraptosis-like form of cell death.

  2. HAMLET triggers apoptosis but tumor cell death is independent of caspases, Bcl-2 and p53.

    PubMed

    Hallgren, O; Gustafsson, L; Irjala, H; Selivanova, G; Orrenius, S; Svanborg, C

    2006-02-01

    HAMLET (Human alpha-lactalbumin Made Lethal to Tumor cells) triggers selective tumor cell death in vitro and limits tumor progression in vivo. Dying cells show features of apoptosis but it is not clear if the apoptotic response explains tumor cell death. This study examined the contribution of apoptosis to cell death in response to HAMLET. Apoptotic changes like caspase activation, phosphatidyl serine externalization, chromatin condensation were detected in HAMLET-treated tumor cells, but caspase inhibition or Bcl-2 over-expression did not prolong cell survival and the caspase response was Bcl-2 independent. HAMLET translocates to the nuclei and binds directly to chromatin, but the death response was unrelated to the p53 status of the tumor cells. p53 deletions or gain of function mutations did not influence the HAMLET sensitivity of tumor cells. Chromatin condensation was partly caspase dependent, but apoptosis-like marginalization of chromatin was also observed. The results show that tumor cell death in response to HAMLET is independent of caspases, p53 and Bcl-2 even though HAMLET activates an apoptotic response. The use of other cell death pathways allows HAMLET to successfully circumvent fundamental anti-apoptotic strategies that are present in many tumor cells.

  3. Bcl-2/Bax protein ratio predicts 5-fluorouracil sensitivity independently of p53 status

    PubMed Central

    Mirjolet, J-F; Barberi-Heyob, M; Didelot, C; Peyrat, J-P; Abecassis, J; Millon, R; Merlin, J-L

    2000-01-01

    p53 tumour-suppressor gene is involved in cell growth control, arrest and apoptosis. Nevertheless cell cycle arrest and apoptosis induction can be observed in p53-defective cells after exposure to DNA-damaging agents such as 5-fluorouracil (5-FU) suggesting the importance of alternative pathways via p53-independent mechanisms. In order to establish relationship between p53 status, cell cycle arrest, Bcl-2/Bax regulation and 5-FU sensitivity, we examined p53 mRNA and protein expression and p53 protein functionality in wild-type (wt) and mutant (mt) p53 cell lines. p53 mRNA and p53 protein expression were determined before and after exposure to equitoxic 5-FU concentration in six human carcinoma cell lines differing in p53 status and displaying marked differences in 5-FU sensitivity, with IC 50 values ranging from 0.2–22.6 mM. 5-FU induced a rise in p53 mRNA expression in mt p53 cell lines and in human papilloma virus positive wt p53 cell line, whereas significant decrease in p53 mRNA expression was found in wt p53 cell line. Whatever p53 status, 5-FU altered p53 transcriptional and translational regulation leading to up-regulation of p53 protein. In relation with p53 functionality, but independently of p53 mutational status, after exposure to 5-FU equitoxic concentration, all cell lines were able to arrest in G1. No relationship was evidenced between G1 accumulation ability and 5-FU sensitivity. Moreover, after 5-FU exposure, Bax and Bcl-2 proteins regulation was under p53 protein control and a statistically significant relationship (r= 0.880,P= 0.0097) was observed between Bcl-2/Bax ratio and 5-FU sensitivity. In conclusion, whatever p53 status, Bcl-2 or Bax induction and Bcl-2/Bax protein ratio were correlated to 5-FU sensitivity. © 2000 Cancer Research Campaign PMID:11044365

  4. Hypoxia-induced Bcl-2 expression in endothelial cells via p38 MAPK pathway

    SciTech Connect

    Zhang, Cui-Li; Song, Fei; Zhang, Jing; Song, Q.H.

    2010-04-16

    Angiogenesis and apoptosis are reciprocal processes in endothelial cells. Bcl-2, an anti-apoptotic protein, has been found to have angiogenic activities. The purpose of this study was to determine the role of Bcl-2 in hypoxia-induced angiogenesis in endothelial cells and to investigate the underlying mechanisms. Human aortic endothelial cells (HAECs) were exposed to hypoxia followed by reoxygenation. Myocardial ischemia and reperfusion mouse model was used and Bcl-2 expression was assessed. Bcl-2 expression increased in a time-dependent manner in response to hypoxia from 2 to 72 h. Peak expression occurred at 12 h (3- to 4-fold, p < 0.05). p38 inhibitor (SB203580) blocked hypoxia-induced Bcl-2 expression, whereas PKC, ERK1/2 and PI3K inhibitors did not. Knockdown of Bcl-2 resulted in decreased HAECs' proliferation and migration. Over-expression of Bcl-2 increased HAECs' tubule formation, whereas knockdown of Bcl-2 inhibited this process. In this model of myocardial ischemia and reperfusion, Bcl-2 expression was increased and was associated with increased p38 MAPK activation. Our results showed that hypoxia induces Bcl-2 expression in HAECs via p38 MAPK pathway.

  5. Bisdemethoxycurcumin enhances X-ray-induced apoptosis possibly through p53/Bcl-2 pathway.

    PubMed

    Enomoto, Atsushi; Yamada, Junko; Morita, Akinori; Miyagawa, Kiyoshi

    2017-03-01

    Bisdemethoxycurcumin (BDMC), which is isolated from the rhizomes of Curcuma longa, has anti-inflammatory and anti-carcinogenic activities. Here we found that BDMC enhanced X-ray-induced apoptosis in human T-cell leukemia MOLT-4 cells. Knockdown of p53 significantly attenuated the radiosensitizing effect of BDMC. However, BDMC did not enhance X-ray-mediated activation of the p53 signaling pathway via p53's transactivation or mitochondrial translocation. On the other hand, BDMC promoted the X-ray-induced dephosphorylation at Ser 70 in Bcl-2's flexible loop regulatory domain and Bcl-2 binding to p53. Overexpressing Bcl-2 completely blocked the BDMC's radiosensitization effect. Our results indicate that BDMC stimulates the dephosphorylation and p53-binding activity of Bcl-2 and suggest that BDMC may induce a neutralization of Bcl-2's anti-apoptotic function, thereby enhancing X-ray-induced apoptosis.

  6. Two Independent Positive Feedbacks and Bistability in the Bcl-2 Apoptotic Switch

    PubMed Central

    Lu, Haizhu; Sun, Tingzhe; Shen, Pingping

    2008-01-01

    Background The complex interplay between B-cell lymphoma 2 (Bcl-2) family proteins constitutes a crucial checkpoint in apoptosis. Its detailed molecular mechanism remains controversial. Our former modeling studies have selected the ‘Direct Activation Model’ as a better explanation for experimental observations. In this paper, we continue to extend this model by adding interactions according to updating experimental findings. Methodology/Principal Findings Through mathematical simulation we found bistability, a kind of switch, can arise from a positive (double negative) feedback in the Bcl-2 interaction network established by anti-apoptotic group of Bcl-2 family proteins. Moreover, Bax/Bak auto-activation as an independent positive feedback can enforce the bistability, and make it more robust to parameter variations. By ensemble stochastic modeling, we also elucidated how intrinsic noise can change ultrasensitive switches into gradual responses. Our modeling result agrees well with recent experimental data where bimodal Bax activation distributions in cell population were found. Conclusions/Significance Along with the growing experimental evidences, our studies successfully elucidate the switch mechanism embedded in the Bcl-2 interaction network and provide insights into pharmacological manipulation of Bcl-2 apoptotic switch as further cancer therapies. PMID:18213378

  7. MCL-1-independent mechanisms of synergy between dual PI3K/mTOR and BCL-2 inhibition in diffuse large B cell lymphoma

    PubMed Central

    Lee, J. Scott; Tang, Sarah S.; Ortiz, Veronica; Vo, Thanh-Trang; Fruman, David A.

    2015-01-01

    The PI3K/AKT/mTOR axis promotes survival and is a frequently mutated pathway in cancer. Yet, inhibitors targeting this pathway are insufficient to induce cancer cell death as single agents in some contexts, including diffuse large B cell lymphoma (DLBCL). In these situations, combinations with inhibitors targeting BCL-2 survival proteins (ABT-199 and ABT-263) may hold potential. Indeed, studies have demonstrated marked synergy in contexts where PI3K/mTOR inhibitors suppress expression of the pro-survival protein, MCL-1. In this study, we use BH3 profiling to confirm that BCL-2 and BCL-XL support survival following PI3K pathway inhibition, and that the dual PI3K/mTOR inhibitor BEZ235 strongly synergizes with BCL-2 antagonists in DLBCL. However, we identify an alternative mechanism of synergy between PI3K/mTOR and BCL-2 inhibitors, independent of MCL-1 down-regulation. Instead, we show that suppression of AKT activation by BEZ235 can induce the mitochondrial accumulation of pro-apoptotic BAD and BIM, and that expression of a constitutively active form of AKT prevents sensitization to BCL-2 antagonism. Thus, our work identifies an additional mechanism of synergy between PI3K pathway inhibitors and BCL-2 antagonists that strengthens the rationale for testing this combination in DLBCL. PMID:26460954

  8. Autophagy blockade sensitizes the anticancer activity of CA-4 via JNK-Bcl-2 pathway

    SciTech Connect

    Li, Yangling; Luo, Peihua; Wang, Jincheng; Dai, Jiabin; Yang, Xiaochun; Wu, Honghai; Yang, Bo He, Qiaojun

    2014-01-15

    Combretastatin A-4 (CA-4) has already entered clinical trials of solid tumors over ten years. However, the limited anticancer activity and dose-dependent toxicity restrict its clinical application. Here, we offered convincing evidence that CA-4 induced autophagy in various cancer cells, which was demonstrated by acridine orange staining of intracellular acidic vesicles, the degradation of p62, the conversion of LC3-I to LC3-II and GFP-LC3 punctate fluorescence. Interestingly, CA-4-mediated apoptotic cell death was further potentiated by pretreatment with autophagy inhibitors (3-methyladenine and bafilomycin A1) or small interfering RNAs against the autophagic genes (Atg5 and Beclin 1). The enhanced anticancer activity of CA-4 and 3-MA was further confirmed in the SGC-7901 xenograft tumor model. These findings suggested that CA-4-elicited autophagic response played a protective role that impeded the eventual cell death while autophagy inhibition was expected to improve chemotherapeutic efficacy of CA-4. Meanwhile, CA-4 treatment led to phosphorylation/activation of JNK and JNK-dependent phosphorylation of Bcl-2. Importantly, JNK inhibitor or JNK siRNA inhibited autophagy but promoted CA-4-induced apoptosis, indicating a key requirement of JNK-Bcl-2 pathway in the activation of autophagy by CA-4. We also identified that pretreatment of Bcl-2 inhibitor (ABT-737) could significantly enhance anticancer activity of CA-4 due to inhibition of autophagy. Taken together, our data suggested that the JNK-Bcl-2 pathway was considered as the critical regulator of CA-4-induced protective autophagy and a potential drug target for chemotherapeutic combination. - Highlights: • Autophagy inhibition could be a potential for combretastatin A-4 antitumor efficacy. • The JNK-Bcl-2 pathway plays a critical role in CA-4-induced autophagy. • ABT-737 enhances CA-4 anticancer activity due to inhibition of autophagy.

  9. Downregulation of autophagy by Bcl-2 promotes MCF7 breast cancer cell growth independent of its inhibition of apoptosis.

    PubMed

    Oh, S; Xiaofei, E; Ni, D; Pirooz, S D; Lee, J-Y; Lee, D; Zhao, Z; Lee, S; Lee, H; Ku, B; Kowalik, T; Martin, S E; Oh, B-H; Jung, J U; Liang, C

    2011-03-01

    The anti-apoptotic Bcl-2 protein, which confers oncogenic transformation and drug resistance in most human cancers, including breast cancer, has recently been shown to effectively counteract autophagy by directly targeting Beclin1, an essential autophagy mediator and tumor suppressor. However, it remains unknown whether autophagy inhibition contributes to Bcl-2-mediated oncogenesis. Here, by using a loss-of-function mutagenesis study, we show that Bcl-2-mediated antagonism of autophagy has a critical role in enhancing the tumorigenic properties of MCF7 breast cancer cells independent of its anti-apoptosis activity. A Bcl-2 mutant defective in apoptosis inhibition but competent for autophagy suppression promotes MCF7 breast cancer cell growth in vitro and in vivo as efficiently as wild-type Bcl-2. The growth-promoting activity of this Bcl-2 mutant is strongly correlated with its suppression of Beclin1-dependent autophagy, leading to sustained p62 expression and increased DNA damage in xenograft tumors, which may directly contribute to tumorigenesis. Thus, the anti-autophagic property of Bcl-2 is a key feature of Bcl-2-mediated oncogenesis and may in some contexts, serve as an attractive target for breast and other cancer therapies.

  10. BCL2 in breast cancer: a favourable prognostic marker across molecular subtypes and independent of adjuvant therapy received

    PubMed Central

    Dawson, S-J; Makretsov, N; Blows, F M; Driver, K E; Provenzano, E; Le Quesne, J; Baglietto, L; Severi, G; Giles, G G; McLean, C A; Callagy, G; Green, A R; Ellis, I; Gelmon, K; Turashvili, G; Leung, S; Aparicio, S; Huntsman, D; Caldas, C; Pharoah, P

    2010-01-01

    Background: Breast cancer is heterogeneous and the existing prognostic classifiers are limited in accuracy, leading to unnecessary treatment of numerous women. B-cell lymphoma 2 (BCL2), an antiapoptotic protein, has been proposed as a prognostic marker, but this effect is considered to relate to oestrogen receptor (ER) status. This study aimed to test the clinical validity of BCL2 as an independent prognostic marker. Methods: Five studies of 11 212 women with early-stage breast cancer were analysed. Individual patient data included tumour size, grade, lymph node status, endocrine therapy, chemotherapy and mortality. BCL2, ER, progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2) levels were determined in all tumours. A Cox model incorporating the time-dependent effects of each variable was used to explore the prognostic significance of BCL2. Results: In univariate analysis, ER, PR and BCL2 positivity was associated with improved survival and HER2 positivity with inferior survival. For ER and PR this effect was time dependent, whereas for BCL2 and HER2 the effect persisted over time. In multivariate analysis, BCL2 positivity retained independent prognostic significance (hazard ratio (HR) 0.76, 95% confidence interval (CI) 0.66–0.88, P<0.001). BCL2 was a powerful prognostic marker in ER− (HR 0.63, 95% CI 0.54–0.74, P<0.001) and ER+ disease (HR 0.56, 95% CI 0.48–0.65, P<0.001), and in HER2− (HR 0.55, 95% CI 0.49–0.61, P<0.001) and HER2+ disease (HR 0.70, 95% CI 0.57–0.85, P<0.001), irrespective of the type of adjuvant therapy received. Addition of BCL2 to the Adjuvant! Online prognostic model, for a subset of cases with a 10-year follow-up, improved the survival prediction (P=0.0039). Conclusions: BCL2 is an independent indicator of favourable prognosis for all types of early-stage breast cancer. This study establishes the rationale for introduction of BCL2 immunohistochemistry to improve prognostic stratification. Further work

  11. Contribution of apoptosis-associated signaling pathways to epileptogenesis: lessons from Bcl-2 family knockouts.

    PubMed

    Henshall, David C; Engel, Tobias

    2013-01-01

    Neuronal cell death is a pathophysiological consequence of many brain insults that trigger epilepsy and has been implicated as a causal factor in epileptogenesis. Seizure-induced neuronal death features excitotoxic necrosis and apoptosis-associated signaling pathways, including activation of multiple members of the Bcl-2 gene family. The availability of mice in which individual Bcl-2 family members have been deleted has provided the means to determine whether they have causal roles in neuronal death and epileptogenesis in vivo. Studies show that multiple members of the Bcl-2 family are activated following status epilepticus and the seizure and damage phenotypes of eight different knockouts of the Bcl-2 family have now been characterized. Loss of certain pro-apoptotic members, including Puma, protected against seizure-induced neuronal death whereas loss of anti-apoptotic Mcl-1 and Bcl-w enhanced hippocampal damage. Notably, loss of two putatively pro-apoptotic members, Bak and Bmf, resulted in more seizure-damage while deletion of Bid had no effect, indicating the role of certain Bcl-2 family proteins in epileptic brain injury is distinct from their contributions following other stressors or in non-CNS tissue. Notably, Puma-deficient mice develop fewer spontaneous seizures after status epilepticus suggesting neuroprotection may preserve functional inhibition, either directly by preserving neuronal networks or indirectly, for example by limiting reactive gliosis and pro-inflammatory responses to neuronal death. Together, these studies support apoptosis-associated molecular mechanisms controlling neuronal death as a component of epileptogenesis which might be targetable to protect against seizure-damage, cognitive deficits and mitigate the severity of syndrome following epilepsy-precipitating injuries to the brain.

  12. BCL-2 Antagonism to Target the Intrinsic Mitochondrial Pathway of Apoptosis.

    PubMed

    Gibson, Christopher J; Davids, Matthew S

    2015-11-15

    Despite significant improvements in treatment, cure rates for many cancers remain suboptimal. The rise of cytotoxic chemotherapy has led to curative therapy for a subset of cancers, though intrinsic treatment resistance is difficult to predict for individual patients. The recent wave of molecularly targeted therapies has focused on druggable-activating mutations, and is thus limited to specific subsets of patients. The lessons learned from these two disparate approaches suggest the need for therapies that borrow aspects of both, targeting biologic properties of cancer that are at once distinct from normal cells and yet common enough to make the drugs widely applicable across a range of cancer subtypes. The intrinsic mitochondrial pathway of apoptosis represents one such promising target for new therapies, and successfully targeting this pathway has the potential to alter the therapeutic landscape of therapy for a variety of cancers. Here, we discuss the biology of the intrinsic pathway of apoptosis, an assay known as BH3 profiling that can interrogate this pathway, early attempts to target BCL-2 clinically, and the recent promising results with the BCL-2 antagonist venetoclax (ABT-199) in clinical trials in hematologic malignancies. See all articles in this CCR Focus section, "Cell Death and Cancer Therapy."

  13. Natural pyrethrins induces apoptosis in human hepatocyte cells via Bax- and Bcl-2-mediated mitochondrial pathway.

    PubMed

    Yang, Yun; Zong, Mimi; Xu, Wenping; Zhang, Yang; Wang, Bo; Yang, Mingjun; Tao, Liming

    2017-01-25

    Natural pyrethrins have been widely used for pest control in organic farming and for residential indoor pest managements. Although the specific mechanisms underlying their activity are incompletely understood, natural pesticides are considered the safest based on their target specificity and rapid degradation in the environment. Here, we used in vitro bioassays to characterize the cytotoxic effects of natural pyrethrins and attempted to delineate the cellular and molecular mechanisms of their cytotoxicity against human hepatocytes. The results demonstrate that natural pyrethrins reduce cell viability and enhance apoptosis in HepG2 cells. In addition, the current data indicate that natural pyrethrins cause a reduction in the mitochondrial membrane potential (Δψm), increase reactive oxygen species production, and up-regulate the Bax/Bcl-2 expression, leading to the release of cytochrome-c into the cytosol, activation of caspase-9 and caspase-3 and cleavage of poly (ADP-ribose) polymerase (PARP). Taken together, the results indicate that natural pyrethrins has potentially exert adverse effects on human health by inducing caspase-dependent apoptosis in hepatocytes through Bax- and Bcl-2-mediated mitochondrial pathway.

  14. Co-targeting of Bcl-2 and mTOR pathway triggers synergistic apoptosis in BH3 mimetics resistant acute lymphoblastic leukemia

    PubMed Central

    Allegretti, Matteo; Mirabilii, Simone; Licchetta, Roberto; Bergamo, Paola; Rinaldo, Cinzia; Zeuner, Ann; Foà, Robin; Milella, Michele; McCubrey, James A.; Martelli, Alberto M.; Tafuri, Agostino

    2015-01-01

    Several chemo-resistance mechanisms including the Bcl-2 protein family overexpression and constitutive activation of the PI3K/Akt/mTOR signaling have been documented in acute lymphoblastic leukemia (ALL), encouraging targeted approaches to circumvent this clinical problem. Here we analyzed the activity of the BH3 mimetic ABT-737 in ALL, exploring the synergistic effects with the mTOR inhibitor CCI-779 on ABT-737 resistant cells. We showed that a low Mcl-1/Bcl-2 plus Bcl-xL protein ratio determined ABT-737 responsiveness. ABT-737 exposure further decreased Mcl-1, inducing apoptosis on sensitive models and primary samples, while not affecting resistant cells. Co-inhibition of Bcl-2 and the mTOR pathway resulted cytotoxic on ABT-737 resistant models, by downregulating mTORC1 activity and Mcl-1 in a proteasome-independent manner. Although Mcl-1 seemed to be critical, ectopic modulation did not correlate with apoptosis changes. Importantly, dual targeting proved effective on ABT-737 resistant samples, showing additive/synergistic effects. Together, our results show the efficacy of BH3 mimetics as single agent in the majority of the ALL samples and demonstrate that resistance to ABT-737 mostly correlated with Mcl-1 overexpression. Co-targeting of the Bcl-2 protein family and mTOR pathway enhanced drug-induced cytotoxicity by suppressing Mcl-1, providing a novel therapeutic approach to overcome BH3 mimetics resistance in ALL. PMID:26392332

  15. Involvement of Bcl-2 Signal Pathway in the Protective Effects of Apigenin on Anoxia/Reoxygenation-induced Myocardium Injury.

    PubMed

    Chen, Chuanjun; He, Huan; Luo, Yong; Zhou, Min; Yin, Dong; He, Ming

    2016-02-01

    Apigenin is a type of flavonoids, which has been demonstrated to protect myocardium against ischemia/reperfusion (I/R) injury. However, the mechanism is still unclear. We hypothesized that the mechanism of cardioprotective action of apigenin on the I/R-induced injury might be caused via B-cell lymphoma (Bcl) signaling pathway. In this study, an in vitro I/R model was replicated on Langendorff-perfused heart and H9c2 cardiomyocytes by anoxia/reoxygenation (A/R) treatment. The recovery of cardiac contractile function, infarct size, lactate dehydrogenase (LDH) and creatine kinase (CK) in the perfusate, the expression and activity of Bcl-2 and caspase-3, and cardiomyocyte apoptosis were measured in the Langendorff heart undergoing A/R injury. In addition, the cell viability, LDH release, intracellular reactive oxygen species (ROS), mitochondrial membrane potential (Δψm), expression of cytochrome c in the cytosol, and cell apoptosis were examined in the culture of H9c2 cardiomyocytes after the A/R. The results showed that apigenin significantly improved rat heart contractile function, reduced LDH release, infarct size and apoptotic rate, upregulated the expression of Bcl-2 and caspase-3, and downregulated the expression of cleaved caspase-3 after the A/R. Moreover, apigenin increased the cell viability and decreased the release of LDH, production of reactive oxygen species, release of mitochondrial cytochrome c into the cytosol, and cell apoptosis in the culture of H9c2 cardiomyocytes after the A/R. In addition, inhibition of Bcl-2 activity by ABT-737 markedly attenuated the protective effect of apigenin on the A/R-induced myocardium injury. Taken together, we firstly demonstrated that the effect of apigenin against A/R injury in cardiomyocytes involves Bcl-2 signal pathway and at least partly depends on its effect of upregulating the expression of Bcl-2.

  16. The BCL2 selective inhibitor venetoclax induces rapid onset apoptosis of CLL cells in patients via a TP53-independent mechanism.

    PubMed

    Anderson, Mary Ann; Deng, Jing; Seymour, John F; Tam, Constantine; Kim, Su Young; Fein, Joshua; Yu, Lijian; Brown, Jennifer R; Westerman, David; Si, Eric G; Majewski, Ian J; Segal, David; Heitner Enschede, Sari L; Huang, David C S; Davids, Matthew S; Letai, Anthony; Roberts, Andrew W

    2016-06-23

    BCL2 blunts activation of the mitochondrial pathway to apoptosis, and high-level expression is required for chronic lymphocytic leukemia (CLL) survival. Venetoclax (ABT-199) is a small-molecule selective inhibitor of BCL2 currently in clinical trials for CLL and other malignancies. In conjunction with the phase 1 first-in-human clinical trial of venetoclax in patients with relapsed or refractory CLL (M12-175), we investigated the mechanism of action of venetoclax in vivo, explored whether in vitro sensitivity assays or BH3 profiling correlated with in vivo responses in patients, and determined whether loss of TP53 function affected responses in vitro and in vivo. In all samples tested, venetoclax induced death of CLL cells in vitro at concentrations achievable in vivo, with cell death evident within 4 hours. Apoptotic CLL cells were detected in vivo 6 or 24 hours after a single 20-mg or 50-mg dose in some patients. The extent of mitochondrial depolarization by a BIM BH3 peptide in vitro was correlated with percentage reduction of CLL in the blood and bone marrow in vivo, whereas the half lethal concentration derived from standard cytotoxicity assays was not. CLL cell death in vitro and the depth of clinical responses were independent of deletion of chromosome 17p, TP53 mutation, and TP53 function. These data provide direct evidence that venetoclax kills CLL cells in a TP53-independent fashion by inhibition of BCL2 in patients and support further assessment of BH3 profiling as a predictive biomarker for this drug.

  17. The BCL2 selective inhibitor venetoclax induces rapid onset apoptosis of CLL cells in patients via a TP53-independent mechanism

    PubMed Central

    Anderson, Mary Ann; Deng, Jing; Seymour, John F.; Tam, Constantine; Kim, Su Young; Fein, Joshua; Yu, Lijian; Brown, Jennifer R.; Westerman, David; Si, Eric G.; Majewski, Ian J.; Segal, David; Heitner Enschede, Sari L.; Huang, David C. S.; Davids, Matthew S.; Letai, Anthony

    2016-01-01

    BCL2 blunts activation of the mitochondrial pathway to apoptosis, and high-level expression is required for chronic lymphocytic leukemia (CLL) survival. Venetoclax (ABT-199) is a small-molecule selective inhibitor of BCL2 currently in clinical trials for CLL and other malignancies. In conjunction with the phase 1 first-in-human clinical trial of venetoclax in patients with relapsed or refractory CLL (M12-175), we investigated the mechanism of action of venetoclax in vivo, explored whether in vitro sensitivity assays or BH3 profiling correlated with in vivo responses in patients, and determined whether loss of TP53 function affected responses in vitro and in vivo. In all samples tested, venetoclax induced death of CLL cells in vitro at concentrations achievable in vivo, with cell death evident within 4 hours. Apoptotic CLL cells were detected in vivo 6 or 24 hours after a single 20-mg or 50-mg dose in some patients. The extent of mitochondrial depolarization by a BIM BH3 peptide in vitro was correlated with percentage reduction of CLL in the blood and bone marrow in vivo, whereas the half lethal concentration derived from standard cytotoxicity assays was not. CLL cell death in vitro and the depth of clinical responses were independent of deletion of chromosome 17p, TP53 mutation, and TP53 function. These data provide direct evidence that venetoclax kills CLL cells in a TP53-independent fashion by inhibition of BCL2 in patients and support further assessment of BH3 profiling as a predictive biomarker for this drug. PMID:27069256

  18. (-)-Epigallocatechingallate induces apoptosis in B lymphoma cells via caspase-dependent pathway and Bcl-2 family protein modulation.

    PubMed

    Wang, Jiangyan; Xie, Yu'an; Feng, Yan; Zhang, Litu; Huang, Xinping; Shen, Xiaoyun; Luo, Xiaoling

    2015-04-01

    (-)-Epigallocatechingallate (EGCG) as a representative polyphenol has attracted increasing attention due to its diversified effects, especially its potential as an agent for the prevention or treatment of certain cancers. However, the molecular mechanisms of EGCG-induced apoptosis in B lymphoma cells are unclear. The aim of this study was to investigate the effect of EGCG on proliferation and apoptosis in the B lymphoma cell lines Jeko-1 and Raji, and determine the underlying mechanisms. Cell proliferation and cytotoxicity were determined by the cell counting kit (CCK-8) assay; apoptosis was assessed by flow cytometry using the Annexin V-PE/7AAD double staining; Fas, Bcl-2 and Bax mRNA expression levels were determined by real-time PCR; caspase activity was measured by the caspase activity assay kit; the expression levels of apoptosis-associated proteins were determined by western blot analysis. We demonstrated that EGCG induced growth inhibition and apoptosis in a dose- and time-dependent manner. In agreement, EGCG upregulated the mRNA expression of Fas and Bax while downregulating Bcl-2. Protein expression levels of Bax, activated caspase-3, -7, -8, and -9, and PARP were increased, while Bcl-2 protein levels were reduced by EGCG treatment. Taken together, EGCG induces B lymphoma cell apoptosis by triggering caspase-dependent intrinsic (mitochondrial) and extrinsic (death receptor) pathways. These findings suggest that EGCG may be a potential agent for the treatment of B lymphoma.

  19. Triggering of Bcl-2-related pathway is associated with apoptosis of photoreceptors in Rpe65-/- mouse model of Leber's congenital amaurosis.

    PubMed

    Cottet, Sandra; Schorderet, Daniel F

    2008-03-01

    Mutations in RPE65 protein is characterized by the loss of photoreceptors, although the molecular pathways triggering retinal cell death remain largely unresolved. The role of the Bcl-2 family of proteins in retinal degeneration is still controversial. However, alteration in Bcl-2-related proteins has been observed in several models of retinal injury. In particular, Bax has been suggested to play a crucial role in apoptotic pathways in murine glaucoma model as well as in retinal detachment-associated cell death. We demonstrated that Bcl-2-related signaling pathway is involved in Rpe65-dependent apoptosis of photoreceptors during development of the disease. Pro-apoptotic Bax alpha and beta isoforms were upregulated in diseased retina. This was associated with a progressive reduction of anti-apoptotic Bcl-2, reflecting imbalanced Bcl-2/Bax ratio as the disease progresses. Moreover, specific translocation of Bax beta from cytosol to mitochondria was observed in Rpe65-deficient retina. This correlated with the initiation of photoreceptor cell loss at 4 months of age, and further increased during disease development. Altogether, these data suggest that Bcl-2-apoptotic pathway plays a crucial role in Leber's congenital amaurosis disease. They further highlight a new regulatory mechanism of Bax-dependent apoptosis based on regulated expression and activation of specific isoforms of this protein.

  20. Moclobemide upregulated Bcl-2 expression and induced neural stem cell differentiation into serotoninergic neuron via extracellular-regulated kinase pathway

    PubMed Central

    Chiou, Shih-Hwa; Ku, Hung-Hai; Tsai, Tung-Hu; Lin, Heng-Liang; Chen, Li-Hsin; Chien, Chan-Shiu; Ho, Larry L -T; Lee, Chen-Hsen; Chang, Yuh-Lih

    2006-01-01

    Moclobemide (MB) is an antidepressant drug that selectively and reversibly inhibits monoamine oxidase-A. Recent studies have revealed that antidepressant drugs possess the characters of potent growth-promoting factors for the development of neurogenesis and improve the survival rate of serotonin (5-hydroxytrytamine; 5-HT) neurons. However, whether MB comprises neuroprotection effects or modulates the proliferation of neural stem cells (NSCs) needs to be elucidated. In this study, firstly, we used the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay to demonstrate that 50 μM MB can increase the cell viability of NSCs. The result of real-time reverse transcription–polymerase chain reaction (RT–PCR) showed that the induction of MB can upregulate the gene expressions of Bcl-2 and Bcl-xL. By using caspases 8 and 3, ELISA and terminal dUTP nick-end labeling (TUNEL) assay, our data further confirmed that 50 μM MB-treated NSCs can prevent FasL-induced apoptosis. The morphological findings also supported the evidence that MB can facilitate the dendritic development and increase the neurite expansion of NSCs. Moreover, we found that MB treatment increased the expression of Bcl-2 in NSCs through activating the extracellular-regulated kinase (ERK) phosphorylation. By using the triple-staining immunofluorescent study, the percentages of serotonin- and MAP-2-positive cells in the day 7 culture of MB-treated NSCs were significantly increased (P<0.01). Furthermore, our data supported that MB treatment increased functional production of serotonin in NSCs via the modulation of ERK1/2. In sum, the study results support that MB can upregulate Bcl-2 expression and induce the differentiation of NSCs into serotoninergic neuron via ERK pathway. PMID:16702990

  1. Insulin involved Akt/ERK and Bcl-2/Bax pathways against oxidative damages in C6 glial cells.

    PubMed

    Ramalingam, Mahesh; Kim, Sung-Jin

    2016-01-01

    Insulin, a hypoglycemic hormone, has multiple functions in the brain. The aim of this study to identify the mechanisms of insulin in hydrogen peroxide (H(2)O(2)-induced toxicity in the C6 glial cells. Cytotoxicity, lactate dehydrogenase, nitric oxide, reactive oxygen species and calcium ion, lipid peroxidation, protein oxidation and glutathione levels were determined. Signaling pathway molecules were assessed by western blotting and RT-PCR. The results showed that treatment with insulin reduced the cell death and cell membrane damages against H(2)O(2)-induced toxicity. Furthermore, insulin interfered H(2)O(2)-induced intracellular generation of reactive oxygen species and calcium-ion transport, apoptosis, including lipid and protein oxidation products. Cells treated with insulin reverted H(2)O(2)-induced suppression of reduced glutathione levels by blocking oxidized glutathione. Moreover, insulin treatment activates Akt, restores ERK1/2 and Bcl-2 by preventing Bax and Bax/Bcl-2 ratio. Our results suggest that treatment of insulin exerts potential role against 24 h of H(2)O(2)-induced toxicity in C6 cells.

  2. Arsenite induces apoptosis in human mesenchymal stem cells by altering Bcl-2 family proteins and by activating intrinsic pathway

    SciTech Connect

    Yadav, Santosh; Shi Yongli; Wang Feng; Wang He

    2010-05-01

    Purpose: Environmental exposure to arsenic is an important public health issue. The effects of arsenic on different tissues and organs have been intensively studied. However, the effects of arsenic on bone marrow mesenchymal stem cells (MSCs) have not been reported. This study is designed to investigate the cell death process caused by arsenite and its related underlying mechanisms on MSCs. The rationale is that absorbed arsenic in the blood circulation can reach to the bone marrow and may affect the cell survival of MSCs. Methods: MSCs of passage 1 were purchased from Tulane University, grown till 70% confluency level and plated according to the experimental requirements followed by treatment with arsenite at various concentrations and time points. Arsenite (iAs{sup III}) induced cytotoxic effects were confirmed by cell viability and cell cycle analysis. For the presence of canonic apoptosis markers; DNA damage, exposure of intramembrane phosphotidylserine, protein and m-RNA expression levels were analyzed. Results: iAs{sup III} induced growth inhibition, G2-M arrest and apoptotic cell death in MSCs, the apoptosis induced by iAs{sup III} in the cultured MSCs was, via altering Bcl-2 family proteins and by involving intrinsic pathway. Conclusion: iAs{sup III} can induce apoptosis in bone marrow-derived MSCs via Bcl-2 family proteins, regulating intrinsic apoptotic pathway. Due to the multipotency of MSC, acting as progenitor cells for a variety of connective tissues including bone, adipose, cartilage and muscle, these effects of arsenic may be important in assessing the health risk of the arsenic compounds and understanding the mechanisms of arsenic-induced harmful effects.

  3. Methylmercury, an environmental electrophile capable of activation and disruption of the Akt/CREB/Bcl-2 signal transduction pathway in SH-SY5Y cells

    PubMed Central

    Unoki, Takamitsu; Abiko, Yumi; Toyama, Takashi; Uehara, Takashi; Tsuboi, Koji; Nishida, Motohiro; Kaji, Toshiyuki; Kumagai, Yoshito

    2016-01-01

    Methylmercury (MeHg) modifies cellular proteins via their thiol groups in a process referred to as “S-mercuration”, potentially resulting in modulation of the cellular signal transduction pathway. We examined whether low-dose MeHg could affect Akt signaling involved in cell survival. Exposure of human neuroblastoma SH-SY5Y cells of up to 2 μM MeHg phosphorylated Akt and its downstream signal molecule CREB, presumably due to inactivation of PTEN through S-mercuration. As a result, the anti-apoptotic protein Bcl-2 was up-regulated by MeHg. The activation of Akt/CREB/Bcl-2 signaling mediated by MeHg was, at least in part, linked to cellular defence because either pretreatment with wortmannin to block PI3K/Akt signaling or knockdown of Bcl-2 enhanced MeHg-mediated cytotoxicity. In contrast, increasing concentrations of MeHg disrupted Akt/CREB/Bcl-2 signaling. This phenomenon was attributed to S-mercuration of CREB through Cys286 rather than Akt. These results suggest that although MeHg is an apoptosis-inducing toxicant, this environmental electrophile is able to activate the cell survival signal transduction pathway at lower concentrations prior to apoptotic cell death. PMID:27357941

  4. Training in Support of Research Project Entitled "Genetic Regulation of the Bcl-2/Bax Cell Death Pathway".

    DTIC Science & Technology

    1998-07-01

    programmed cell death in mammals, Bcl-2 family proteins can also induce or prevent cell death in the unicellular yeast; overexpression of Bax causes lethality...in both S. cerevisiae and S. pombe, and co-expression of either Bcl-2 or Bcl-XL can protect yeast against Bax-caused cell death . On the basis of these...observations, we have developed a functional screen and have identified two human genes, BI-1 and BI-2, which inhibit Bax-induced cell death in yeast

  5. IL-15 regulates Bcl-2 family members Bim and Mcl-1 through JAK/STAT and PI3K/AKT pathways in T cells.

    PubMed

    Shenoy, Aparna R; Kirschnek, Susanne; Häcker, Georg

    2014-08-01

    Maintenance of T cells is determined by their survival capacity, which is regulated by Bcl-2 proteins. Cytokines signalling through the common gamma chains such as IL-2, IL-7 and IL-15 are important for T-cell survival but how these cytokines determine the expression of Bcl-2-family proteins is not clear. We report signalling events of cytokines that regulate expression of two key Bcl-2 proteins, pro-apoptotic Bim and anti-apoptotic Mcl-1, in resting C57BL/6 mouse T cells. IL-2, IL-7 and IL-15 inhibited apoptosis but paradoxically induced the expression of Bim, countered by concomitant induction of Mcl-1. Bim induction by IL-15 was found at the mRNA and protein levels and depended on both JAK/STAT and PI3K signals. A new STAT5-binding site was identified in the Bim promoter, which was occupied by STAT5 upon IL-15 stimulation. Although it also depended on JAK/STAT- and PI3K signalling, Mcl-1 regulation was independent of Mcl-1 mRNA levels and of regulation of protein stability, suggesting translational regulation. Concurrent CD3 signals inhibited some of the IL-7 effect but not the IL-15 effect on Bcl-2 proteins. The data suggest that cytokines induce Bim and prime T cells for apoptosis, but also inhibit apoptosis by stabilising Mcl-1. Later downregulation of short-lived Mcl-1 may induce efficient, Bim-dependent apoptosis.

  6. RLIP76-dependent suppression of PI3K/AKT/Bcl-2 pathway by miR-101 induces apoptosis in prostate cancer

    SciTech Connect

    Yang, Jing; Song, Qi; Cai, Yi; Wang, Peng; Wang, Min; Zhang, Dong

    2015-08-07

    MicroRNA-101 (miR-101) participates in carcinogenesis and tumor progression in various cancers. However, its biological functions in prostate cancer are still unclear. Here, we demonstrate that miR-101 represents a critical role in regulating cell apoptosis in prostate cancer cells. We first demonstrated that miR-101 treatment promoted apoptosis in DU145 and PC3 cells by using flow cytometric analysis and transmission electron microscopy (TEM). To verify the mechanisms, we identified a novel miR-101 target, Ral binding protein 1 (RLIP76). We found miR-101 transfection significantly suppresses RLIP76 expression, which can transactivate phosphorylation of PI3K-Akt signaling, and resulted in an amplification of Bcl2-induced apoptosis. Furthermore, we demonstrated that RLIP76 overexpression could reverse the anti-tumor effects of miR-101 in DU145 and PC3 cells by using flow cytometry assay and MTT assay. Taken together, our results revealed that the effect of miR-101 on prostate cancer cell apoptosis was due to RLIP76 regulation of the PI3K/Akt/Bcl-2 signaling pathway. - Highlights: • miR-101 inhibited prostate cancer cell proliferation and enhanced apoptosis. • miR-101 directly targeted and regulated RLIP76 expression. • miR-101 suppressed PI3K/Akt/Bcl-2 signaling pathway by targeting RLIP76.

  7. Neuroprotective Effects of β-Asarone Against 6-Hydroxy Dopamine-Induced Parkinsonism via JNK/Bcl-2/Beclin-1 Pathway.

    PubMed

    Zhang, Sheng; Gui, Xue-Hong; Huang, Li-Ping; Deng, Min-Zhen; Fang, Ruo-Ming; Ke, Xue-Hong; He, Yu-Ping; Li, Ling; Fang, Yong-Qi

    2016-01-01

    β-asarone, a major component of Acorus tatarinowii Schott, has positive effects in neurodegeneration disease, however, its effect on the Parkinson's disease (PD) remains unclear. In this study, the effects of β-asarone on behavioral tests, neurotransmitters, tyrosine hydroxylase (TH), and α-synuclein (α-syn) were investigated in 6-hydroxydopamine (6-OHDA) induced rats. Furthermore, the JNK/Bcl-2/Beclin-1 autophagy pathway was also studied. The results showed that β-asarone improved the behavioral symptoms of rats in the open field, rotarod test, initiation time, and stepping time. And it increased the HVA, Dopacl, and 5-HIAA levels in striatum but not the DA and 5-HT levels. After administration of β-asarone, the TH level was elevated but the α-syn was declined in rats. It inhibited the expressions of LC3-II, but increased the p62 expression in SN4741 cells. Moreover, it affected the expressions of Beclin-1, Bcl-2, JNK, and p-JNK in vivo. We deduced that β-asarone may firstly downregulate expressions of JNK and p-JNK, and then indirectly increase the expression of Bcl-2. And the function of Beclin-1 could be inhibited, which could inhibit autophagy activation. Collectively, all data indicated that β-asarone may be explored as a potential therapeutic agent in PD therapy.

  8. BCL2DB: database of BCL-2 family members and BH3-only proteins

    PubMed Central

    Rech de Laval, Valentine; Deléage, Gilbert; Aouacheria, Abdel; Combet, Christophe

    2014-01-01

    BCL2DB (http://bcl2db.ibcp.fr) is a database designed to integrate data on BCL-2 family members and BH3-only proteins. These proteins control the mitochondrial apoptotic pathway and probably many other cellular processes as well. This large protein group is formed by a family of pro-apoptotic and anti-apoptotic homologs that have phylogenetic relationships with BCL-2, and by a collection of evolutionarily and structurally unrelated proteins characterized by the presence of a region of local sequence similarity with BCL-2, termed the BH3 motif. BCL2DB is monthly built, thanks to an automated procedure relying on a set of homemade profile HMMs computed from seed reference sequences representative of the various BCL-2 homologs and BH3-only proteins. The BCL2DB entries integrate data from the Ensembl, Ensembl Genomes, European Nucleotide Archive and Protein Data Bank databases and are enriched with specific information like protein classification into orthology groups and distribution of BH motifs along the sequences. The Web interface allows for easy browsing of the site and fast access to data, as well as sequence analysis with generic and specific tools. BCL2DB provides a helpful and powerful tool to both ‘BCL-2-ologists’ and researchers working in the various fields of physiopathology. Database URL: http://bcl2db.ibcp.fr PMID:24608034

  9. The C. elegans protein CEH-30 protects male-specific neurons from apoptosis independently of the Bcl-2 homolog CED-9.

    PubMed

    Schwartz, Hillel T; Horvitz, H Robert

    2007-12-01

    The developmental control of apoptosis is fundamental and important. We report that the Caenorhabditis elegans Bar homeodomain transcription factor CEH-30 is required for the sexually dimorphic survival of the male-specific CEM (cephalic male) sensory neurons; the homologous cells of hermaphrodites undergo programmed cell death. We propose that the cell-type-specific anti-apoptotic gene ceh-30 is transcriptionally repressed by the TRA-1 transcription factor, the terminal regulator of sexual identity in C. elegans, to cause hermaphrodite-specific CEM death. The established mechanism for the regulation of specific programmed cell deaths in C. elegans is the transcriptional control of the BH3-only gene egl-1, which inhibits the Bcl-2 homolog ced-9; similarly, most regulation of vertebrate apoptosis involves the Bcl-2 superfamily. In contrast, ceh-30 acts within the CEM neurons to promote their survival independently of both egl-1 and ced-9. Mammalian ceh-30 homologs can substitute for ceh-30 in C. elegans. Mice lacking the ceh-30 homolog Barhl1 show a progressive loss of sensory neurons and increased sensory-neuron cell death. Based on these observations, we suggest that the function of Bar homeodomain proteins as cell-type-specific inhibitors of apoptosis is evolutionarily conserved.

  10. IPS-1 differentially induces TRAIL, BCL2, BIRC3 and PRKCE in type I interferons-dependent and -independent anticancer activity.

    PubMed

    Kumar, S; Ingle, H; Mishra, S; Mahla, R S; Kumar, A; Kawai, T; Akira, S; Takaoka, A; Raut, A A; Kumar, H

    2015-05-07

    RIG-I-like receptors are the key cytosolic sensors for RNA viruses and induce the production of type I interferons (IFN) and pro-inflammatory cytokines through a sole adaptor IFN-β promoter stimulator-1 (IPS-1) (also known as Cardif, MAVS and VISA) in antiviral innate immunity. These sensors also have a pivotal role in anticancer activity through induction of apoptosis. However, the mechanism for their anticancer activity is poorly understood. Here, we show that anticancer vaccine adjuvant, PolyIC (primarily sensed by MDA5) and the oncolytic virus, Newcastle disease virus (NDV) (sensed by RIG-I), induce anticancer activity. The ectopic expression of IPS-1 into type I IFN-responsive and non-responsive cancer cells induces anticancer activity. PolyIC transfection and NDV infection upregulate pro-apoptotic gene TRAIL and downregulate the anti-apoptotic genes BCL2, BIRC3 and PRKCE. Furthermore, stable knockdown of IPS-1, IRF3 or IRF7 in IFN-non-responsive cancer cells show reduced anticancer activity by suppressing apoptosis via TRAIL and anti-apoptotic genes. Collectively, our study shows that IPS-1 induces anticancer activity through upregulation of pro-apoptotic gene TRAIL and downregulation of the anti-apoptotic genes BCL2, BIRC3 and PRKCE via IRF3 and IRF7 in type I IFN-dependent and -independent manners.

  11. Anti-apoptotic BCL-2 family proteins in acute neural injury

    PubMed Central

    Anilkumar, Ujval; Prehn, Jochen H. M.

    2014-01-01

    Cells under stress activate cell survival and cell death signaling pathways. Cell death signaling frequently converges on mitochondria, a process that is controlled by the activities of pro- and anti-apoptotic B-cell lymphoma 2 (BCL-2) proteins. In this review, we summarize current knowledge on the control of neuronal survival, development and injury by anti-apoptotic BCL-2 family proteins. We discuss overlapping and differential effects of the individual family members BCL-2, BCL-extra long (BCL-XL), myeloid cell leukemia 1 (MCL-1), and BCL2-like 2 (BCL-W) in the control of survival during development and pathophysiological processes such as trophic factor withdrawal, ischemic injury, excitotoxicity, oxidative stress and energy stress. Finally we discuss recent evidence that several anti-apoptotic BCL-2 proteins influence mitochondrial bioenergetics and control neuronal Ca2+ homeostasis independent of their classical role in cell death signaling. PMID:25324720

  12. The MUC1 oncomucin regulates pancreatic cancer cell biological properties and chemoresistance. Implication of p42–44 MAPK, Akt, Bcl-2 and MMP13 pathways

    SciTech Connect

    Tréhoux, Solange; Duchêne, Bélinda; Jonckheere, Nicolas; Van Seuningen, Isabelle

    2015-01-16

    Highlights: • Loss of MUC1 decreases proliferation and tumor growth via β-catenin and p42–44 MAPK. • Inhibition of MUC1 decreases cell migration and invasion through MMP13. • Loss of MUC1 decreases survival and increases apoptosis via Akt and Bcl-2 pathways. • Loss of MUC1 sensitizes cells to gemcitabine and 5-Fluorouracil chemotherapeutic drugs. - Abstract: MUC1 is an oncogenic mucin overexpressed in several epithelial cancers, including pancreatic ductal adenocarcinoma, and is considered as a potent target for cancer therapy. To this aim, we undertook to study MUC1 biological effects on pancreatic cancer cells and identify pathways mediating these effects. Our in vitro experiments indicate that inhibiting MUC1 expression decreases cell proliferation, cell migration and invasion, cell survival and increases cell apoptosis. Moreover, lack of MUC1 in these cells profoundly altered their sensitivity to gemcitabine and 5-Fluorouracil chemotherapeutic drugs. In vivo MUC1-KD cell xenografts in SCID mice grew slower. Altogether, we show that MUC1 oncogenic mucin alters proliferation, migration, and invasion properties of pancreatic cancer cells and that these effects are mediated by p42–44 MAPK, Akt, Bcl-2 and MMP13 pathways.

  13. JNK-Bcl-2/Bcl-xL-Bax/Bak Pathway Mediates the Crosstalk between Matrine-Induced Autophagy and Apoptosis via Interplay with Beclin 1

    PubMed Central

    Yang, Jiong; Yao, Shukun

    2015-01-01

    Autophagy is associated with drug resistance which has been a threat in chemotherapy of hepatocellular carcinoma (HCC). The interconnected molecular regulators between autophagy and apoptosis serve as switching points critical to the ultimate outcome of the cell. Our study was performed to investigate the crosstalk between autophagy and apoptosis in HCC after the treatment of matrine. Flow cytometry and TUNEL (terminal dexynucleotidyl transferase (TdT)-mediated dUTP nick end labeling) assay were used to detect apoptosis in vitro and in vivo, respectively. Bax oligomerization and Cytochrome c release assay were performed. Immunoprecipitation and siRNA transfection were used to detect the interplay between Bcl-2/Bcl-xL,Bax, and Beclin 1. Our results showed that: (1) matrine not only activated caspase and PARP (poly ADP-ribose polymerase) cleavage, but also triggered autophagy as shown by the increased levels of LC3II, Beclin 1, and PI3KC3, and the decreased level of p62; (2) matrine treatment promoted the JNK-Bcl-2/Bcl-xL-Bax/Bak pathway; (3) Bax was oligomerized, the mitochondrial membrane potential altered, and Cytochrome c was released subsequently; (4) Bax interacts with Beclin 1 and inhibits autophagy, which may be a new crosstalk point; and (5) finally, we showed that matrine suppressed the growth of a MHCC97L xenograft in vivo for the first time. In conclusion, the JNK-Bcl-2/Bcl-xL-Bax/Bak pathway mediates the crosstalk between matrine-induced autophagy and apoptosis via interplay with Beclin 1. PMID:26516844

  14. Alantolactone induces apoptosis of human cervical cancer cells via reactive oxygen species generation, glutathione depletion and inhibition of the Bcl-2/Bax signaling pathway

    PubMed Central

    JIANG, YAN; XU, HANJIE; WANG, JIAFEI

    2016-01-01

    Alantolactone is the active ingredient in frankincense, and is extracted from the dry root of elecampane. It has a wide variety of uses, including as an insect repellent, antibacterial, antidiuretic, analgesic and anticancer agent. In addition, alantolactone induces apoptosis of human cervical cancer cells, however, its mechanism of action remains to be elucidated. Therefore, the present study investigated whether alantolactone was able to induce apoptosis of human cervical cancer cells, and its potential mechanisms of action were analyzed. Treatment of HeLa cells with alantolactone (0, 10, 20, 30, 40, 50 and 60 µM) for 12 h significantly inhibited growth in a dose-dependent manner. Cells treated with 30 µM of alantolactone for 0, 3, 6 and 12 h demonstrated marked induction of apoptosis in a time-dependent manner. Treatment of HeLa cells with 30 µM of alantolactone for 0, 3, 6 and 12 h significantly induced the generation of reactive oxygen species (ROS) and inhibited glutathione (GSH) production in HeLa cells in a dose-dependent manner. Alantolactone additionally markedly inhibited the Bcl-2/Bax signaling pathway in HeLa cells. Therefore, administration of alantolactone induced apoptosis of human cervical cancer cells via ROS generation, GSH depletion and inhibition of the Bcl-2/Bax signaling pathway. PMID:27313767

  15. Acetylated Chitosan Oligosaccharides Act as Antagonists against Glutamate-Induced PC12 Cell Death via Bcl-2/Bax Signal Pathway

    PubMed Central

    Hao, Cui; Gao, Lixia; Zhang, Yiran; Wang, Wei; Yu, Guangli; Guan, Huashi; Zhang, Lijuan; Li, Chunxia

    2015-01-01

    Chitosan oligosaccharides (COSs), depolymerized products of chitosan composed of β-(1→4) d-glucosamine units, have broad range of biological activities such as antitumour, antifungal, and antioxidant activities. In this study, peracetylated chitosan oligosaccharides (PACOs) and N-acetylated chitosan oligosaccharides (NACOs) were prepared from the COSs by chemcal modification. The structures of these monomers were identified using NMR and ESI-MS spectra. Their antagonist effects against glutamate-induced PC12 cell death were investigated. The results showed that pretreatment of PC12 cells with the PACOs markedly inhibited glutamate-induced cell death in a concentration-dependent manner. The PACOs were better glutamate antagonists compared to the COSs and the NACOs, suggesting the peracetylation is essential for the neuroprotective effects of chitosan oligosaccharides. In addition, the PACOs pretreatment significantly reduced lactate dehydrogenase release and reactive oxygen species production. It also attenuated the loss of mitochondrial membrane potential. Further studies indicated that the PACOs inhibited glutamate-induced cell death by preventing apoptosis through depressing the elevation of Bax/Bcl-2 ratio and caspase-3 activation. These results suggest that PACOs might be promising antagonists against glutamate-induced neural cell death. PMID:25775423

  16. Bilberry extract (Antho 50) selectively induces redox-sensitive caspase 3-related apoptosis in chronic lymphocytic leukemia cells by targeting the Bcl-2/Bad pathway

    PubMed Central

    Alhosin, Mahmoud; León-González, Antonio J.; Dandache, Israa; Lelay, Agnès; Rashid, Sherzad K.; Kevers, Claire; Pincemail, Joël; Fornecker, Luc-Matthieu; Mauvieux, Laurent; Herbrecht, Raoul; Schini-Kerth, Valérie B.

    2015-01-01

    Defect in apoptosis has been implicated as a major cause of resistance to chemotherapy observed in B cell chronic lymphocytic leukaemia (B CLL). This study evaluated the pro-apoptotic effect of an anthocyanin-rich dietary bilberry extract (Antho 50) on B CLL cells from 30 patients and on peripheral blood mononuclear cells (PBMCs) from healthy subjects, and determined the underlying mechanism. Antho 50 induced concentration- and time-dependent pro-apoptotic effects in B CLL cells but little or no effect in PBMCs. Among the main phenolic compounds of the bilberry extract, delphinidin-3-O-glucoside and delphinidin-3-O-rutinoside induced a pro-apoptotic effect. Antho 50-induced apoptosis is associated with activation of caspase 3, down-regulation of UHRF1, a rapid dephosphorylation of Akt and Bad, and down-regulation of Bcl-2. Antho 50 significantly induced PEG-catalase-sensitive formation of reactive oxygen species in B CLL cells. PEG-catalase prevented the Antho 50-induced induction of apoptosis and related signaling. The present findings indicate that Antho 50 exhibits strong pro-apoptotic activity through redox-sensitive caspase 3 activation-related mechanism in B CLL cells involving dysregulation of the Bad/Bcl-2 pathway. This activity of Antho 50 involves the glucoside and rutinoside derivatives of delphinidin. They further suggest that Antho 50 has chemotherapeutic potential by targeting selectively B CLL cells. PMID:25757575

  17. Interleukin 7 signaling prevents apoptosis by regulating bcl-2 and bax via the p53 pathway in human non-small cell lung cancer cells.

    PubMed

    Liu, Zi-Hui; Wang, Ming-Hui; Ren, Hong-Jiu; Qu, Wei; Sun, Li-Mei; Zhang, Qing-Fu; Qiu, Xue-Shan; Wang, En-Hua

    2014-01-01

    Interleukin 7/Interleukin 7 receptor (IL-7/IL-7R) signaling induces the upregulation of cyclin D1 to promote cell proliferation in lung cancer, but its role in preventing the apoptosis of non-small cell lung cancer (NSCLC) cell lines remains unknown. To study the role of IL-7 in lung cancer cell apoptosis, normal HBE cells as well as A549 and H1299 NSCLC cells were examined using flow cytometry. The results showed that the activation of IL-7R by its specific ligand, exogenous interleukin-7, was associated with a significant decline in apoptotic cells. Western blot and real-time PCR assays indicated that the activation of IL-7/IL-7R significantly upregulated anti-apoptotic bcl-2 and downregulated pro-apoptotic bax and p53 at both protein and mRNA levels. The knockdown of IL-7R through small interfering RNAs significantly attenuated these effects of exogenous IL-7. However, there was no significant anti-apoptotic effect in H1299 (p53-) cells. Furthermore, the inhibition of p53 significantly abolished the effects of IL-7/IL-7R on lung cancer cell apoptosis. These results strongly suggest that IL-7/IL-7R prevents apoptosis by upregulating the expression of bcl-2 and by downregulating the expression of bax, potentially via the p53 pathway in A549 and HBE cells.

  18. Levofloxacin increases the effect of serum deprivation on anoikis of rat nucleus pulposus cells via Bax/Bcl-2/caspase-3 pathway.

    PubMed

    Yang, Si-Dong; Bai, Zhi-Long; Zhang, Feng; Ma, Lei; Yang, Da-Long; Ding, Wen-Yuan

    2014-12-01

    Levofloxacin, a fluoroquinolone, is a widely-used and effective antibiotic. However, various adverse side effects are associated with levofloxacin. The purpose of this study was to further explore the effects of levofloxacin on rat nucleus pulposus cells (NPCs). Inverted phase-contrast microscopy, flow cytometry and caspase-3 activity assays were used and revealed that serum deprivation induced apoptosis, which was markedly increased by levofloxacin in a dose-dependent manner. Simultaneously, levofloxacin decreased cell binding to type II collagen (COL2). Thus, levofloxacin-induced apoptosis exhibits characteristics of anoikis, the process by which cell death is triggered by separation from the extracellular matrix, which contains COL2. Furthermore, real-time quantitative RT-PCR was used to further confirm that levofloxacin downregulates COL2 expression in a dose-dependent manner. At last, western blot was used to find that levofloxacin increased the ratio of Bax/Bcl-2 and active caspase-3 in a dose-dependent manner. Levofloxacin therefore increases the effects of serum deprivation on anoikis by downregulating COL2 in rat NPCs in vitro via Bax/Bcl-2/caspase-3 pathway. This research provides a novel insight into the mechanisms of levofloxacin-induced toxicity and may potentially lead to a better understanding of the clinical effects of levofloxacin, especially in terms of intervertebral disc degeneration.

  19. Perfluorocarbon reduces cell damage from blast injury by inhibiting signal paths of NF-κB, MAPK and Bcl-2/Bax signaling pathway in A549 cells

    PubMed Central

    Li, Huaidong; Li, Chunsun; Yang, Zhen; Li, Yanqin; She, Danyang; Cao, Lu; Wang, Wenjie; Liu, Changlin; Chen, Liangan

    2017-01-01

    Background and objective Blast lung injury is a common type of blast injury and has very high mortality. Therefore, research to identify medical therapies for blast injury is important. Perfluorocarbon (PFC) is used to improve gas exchange in diseased lungs and has anti-inflammatory functions in vitro and in vivo. The aim of this study was to determine whether PFC reduces damage to A549 cells caused by blast injury and to elucidate its possible mechanisms of action. Study design and methods A549 alveolar epithelial cells exposed to blast waves were treated with and without PFC. Morphological changes and apoptosis of A549 cells were recorded. PCR and enzyme-linked immunosorbent assay (ELISA) were used to measure the mRNA or protein levels of IL-1β, IL-6 and TNF-α. Malondialdehyde (MDA) levels and superoxide dismutase (SOD) activity levels were detected. Western blot was used to quantify the expression of NF-κB, Bax, Bcl-2, cleaved caspase-3 and MAPK cell signaling proteins. Results A549 cells exposed to blast wave shrank, with less cell-cell contact. The morphological change of A549 cells exposed to blast waves were alleviated by PFC. PFC significantly inhibited the apoptosis of A549 cells exposed to blast waves. IL-1β, IL-6 and TNF-α cytokine and mRNA expression levels were significantly inhibited by PFC. PFC significantly increased MDA levels and decreased SOD activity levels. Further studies indicated that NF-κB, Bax, caspase-3, phospho-p38, phosphor-ERK and phosphor-JNK proteins were also suppressed by PFC. The quantity of Bcl-2 protein was increased by PFC. Conclusion Our research showed that PFC reduced A549 cell damage caused by blast injury. The potential mechanism may be associated with the following signaling pathways: 1) the signaling pathways of NF-κB and MAPK, which inhibit inflammation and reactive oxygen species (ROS); and 2) the signaling pathways of Bcl-2/Bax and caspase-3, which inhibit apoptosis. PMID:28323898

  20. Antiapoptotic and Antioxidant Properties of Orthosiphon stamineus Benth (Cat's Whiskers): Intervention in the Bcl-2-Mediated Apoptotic Pathway

    PubMed Central

    Abdelwahab, Siddig Ibrahim; Mohan, Syam; Mohamed Elhassan, Manal; Al-Mekhlafi, Nabil; Mariod, Abdelbasit Adam; Abdul, Ahmad Bustamam; Abdulla, Mahmood Ameen; Alkharfy, Khalid M.

    2011-01-01

    Antiapoptotic and antioxidant activities of aqueous-methanolic extract (CAME) of Orthosiphonstamineus Benth(OS), and its hexane (HF), chloroform (CF), n-butanol (NBF), ethyl acetate (EAF) and water (WF) fractions were investigated. Antioxidant properties were evaluated using the assays of Folin-Ciocalteu, aluminiumtrichloride, β-carotene bleaching and DPPH. The role of OS against hydrogen peroxide induced apoptosis on MDA-M231 epithelial cells was examined using MTT assay, phase contrast microscope, colorimetric assay of caspase-3, western blot and quantitative real-time PCR. Results showed that EAF showed the highest total phenolic content followed by CAME, NBF, WF, CF and HF, respectively. Flavonoid content was in the order of the CF > EAF > HF > CAME > NBF > WF. The IC50 values on DPPH assay for different extract/fractions were 126.2 ± 23, 31.25 ± 1.2, 15.25 ± 2.3, 13.56 ± 1.9, 23.0 ± 3.2, and 16.66 ± 1.5 μg/ml for HF, CF, EAF, NBF, WF and CAME, respectively. OSreduced the oxidation of β-carotene by hydroperoxides. Cell death was dose-dependently inhibited by pretreatment with OS. Caspase-3 and distinct morphological features suggest the anti-apoptotic activities of OS. This plant not only increased the expression of Bcl-2, but also decreased Bax expression, and ultimately reduced H2O2-induced apoptosis. The current results showed that phenolics may provide health and nutritional benefits. PMID:21234328

  1. Bcl-rambo, a novel Bcl-2 homologue that induces apoptosis via its unique C-terminal extension.

    PubMed

    Kataoka, T; Holler, N; Micheau, O; Martinon, F; Tinel, A; Hofmann, K; Tschopp, J

    2001-06-01

    The Bcl-2 family of proteins plays a central regulatory role in apoptosis. We have identified a novel, widely expressed Bcl-2 member which we have named Bcl-rambo. Bcl-rambo shows overall structural homology to the anti-apoptotic Bcl-2 members containing conserved Bcl-2 homology (BH) motifs 1, 2, 3, and 4. Unlike Bcl-2, however, the C-terminal membrane anchor region is preceded by a unique 250 amino acid insertion containing two tandem repeats. No interaction of Bcl-rambo with either anti-apoptotic (Bcl-2, Bcl-x(L), Bcl-w, A1, MCL-1, E1B-19K, and BHRF1) or pro-apoptotic (Bax, Bak, Bik, Bid, Bim, and Bad) members of the Bcl-2 family was observed. In mammalian cells, Bcl-rambo was localized to mitochondria, and its overexpression induces apoptosis that is specifically blocked by the caspase inhibitors, IAPs, whereas inhibitors controlling upstream events of either the 'death receptor' (FLIP, FADD-DN) or the 'mitochondrial' pro-apoptotic pathway (Bcl-x(L)) had no effect. Surprisingly, the Bcl-rambo cell death activity was induced by its membrane-anchored C-terminal domain and not by the Bcl-2 homology region. Thus, Bcl-rambo constitutes a novel type of pro-apoptotic Bcl-2 member that triggers cell death independently of its BH motifs.

  2. Exosomes derived from human platelet-rich plasma prevent apoptosis induced by glucocorticoid-associated endoplasmic reticulum stress in rat osteonecrosis of the femoral head via the Akt/Bad/Bcl-2 signal pathway

    PubMed Central

    Tao, Shi-Cong; Yuan, Ting; Rui, Bi-Yu; Zhu, Zhen-Zhong; Guo, Shang-Chun; Zhang, Chang-Qing

    2017-01-01

    An excess of glucocorticoids (GCs) is reported to be one of the most common causes of osteonecrosis of the femoral head (ONFH). In addition, GCs can induce bone cell apoptosis through modulating endoplasmic reticulum (ER) stress. Among the three main signal pathways in ER stress, the PERK (protein kinase RNA-like ER kinase)/CHOP (CCAAT-enhancer-binding protein homologous protein) pathway has been considered to be closely associated with apoptosis. Platelet-rich plasma (PRP) has been referred to as a concentration of growth factors and the exosomes derived from PRP (PRP-Exos) have a similar effect to their parent material. The enriched growth factors can be encapsulated into PRP-Exos and activate Akt and Erk pathways to promote angiogenesis. Activation of the Akt pathway may promote the expression of anti-apoptotic proteins like Bcl-2, while CHOP can inhibit B-cell lymphoma 2 (Bcl-2) expression to increase the level of cleaved caspase-3 and lead to cell death. Consequently, we hypothesized that PRP-Exos prevent apoptosis induced by glucocorticoid-associated ER stress in rat ONFH via the Akt/Bad/Bcl-2 signal pathway. To verify this hypothesis, a dexamethasone (DEX)-treated in vitro cell model and methylprednisolone (MPS)-treated in vivo rat model were adopted. Characterization of PRP-Exos, and effects of PRP-Exos on proliferation, apoptosis, angiogenesis, and osteogenesis of cells treated with GCs in vitro and in vivo were examined. Furthermore, the mechanism by which PRP-Exos rescue the GC-induced apoptosis through the Akt/Bad/Bcl-2 pathway was also investigated. The results indicate that PRP-Exos have the capability to prevent GC-induced apoptosis in a rat model of ONFH by promoting Bcl-2 expression via the Akt/Bad/Bcl-2 signal pathway under ER stress. PMID:28255363

  3. Granzyme H induces cell death primarily via a Bcl-2-sensitive mitochondrial cell death pathway that does not require direct Bid activation.

    PubMed

    Ewen, Catherine L; Kane, Kevin P; Bleackley, R Chris

    2013-07-01

    Natural killer and T cell-mediated cytotoxicity is important for the elimination of viruses and transformed cells. The granule lytic pathway utilizes perforin and granzymes to induce cell death, while receptor-mediated lytic pathways rely on molecules such as FasL. Pro-apoptotic activities of Granzyme B (GrB) and Fas are well-established, and many of their cellular targets have been identified. However, humans express additional related granzymes - GrA, GrM, GrK, and GrH. Neither the cytotoxic potential of GrH, nor the mechanism by which GrH may induce target cell death is currently understood. We proposed that GrH would have pro-apoptotic activity that would be distinct from that of GrB and FasL, which could be relevant when Fas/FasL or GrB activity or death pathways were impaired. Our results, using a purified recombinant form of GrH, revealed that GrH induced cell death via a Bcl-2-sensitive mitochondrial pathway without direct processing of Bid. Additionally, neither the apoptosome nor caspase-3 was essential to the induction of GrH-mediated cell death. However, GrH did directly process DFF45, potentially leading to DNA damage. Our findings support the idea that multiple, non-redundant death pathways may be initiated by cytotoxic cells to counteract various immune evasion strategies.

  4. Interferon-alpha and bortezomib overcome Bcl-2 and Mcl-1 over-expression in melanoma cells by stimulating the extrinsic pathway of apoptosis

    PubMed Central

    Lesinski, Gregory B.; Raig, Ene T.; Guenterberg, Kristan; Brown, Lloyd; Go, Michael R.; Shah, Nisha N.; Lewis, Adrian; Quimper, Megan; Hade, Erinn; Young, Gregory; Chaudhury, Abhik Ray; Ladner, Katherine J.; Guttridge, Denis C.; Bouchard, Page

    2008-01-01

    We hypothesized that interferon-alpha (IFN-α) would enhance the apoptotic activity of bortezomib on melanoma cells. Combined treatment with bortezomib and IFN-α induced synergistic apoptosis in melanoma and other solid tumor cell lines. Apoptosis was associated with processing of procaspases-3, -7, -8, -9, and with cleavage of Bid and PARP. Bortezomib plus IFN-α was effective at inducing apoptosis in melanoma cells that over-expressed Bcl-2 or Mcl-1, suggesting that this treatment combination can overcome mitochondrial pathways of cell survival and resistance to apoptosis. The pro-apoptotic effects of this treatment combination were abrogated by a caspase-8 inhibitor, led to increased association of Fas and FADD prior to the onset of cell death, and were significantly reduced in cells transfected with a dominant-negative FADD construct or siRNA targeting Fas. These data suggest that bortezomib and IFN-α act through the extrinsic pathway of apoptosis via FADD-induced caspase-8 activation to initiate cell death. Finally, bortezomib and IFN-α displayed statistically significant anti-tumor activity as compared to either agent alone in both the B16 murine model of melanoma and in athymic mice bearing human A375 xenografts. These data support the future clinical development of bortezomib and IFN-α for malignant melanoma. PMID:18922907

  5. Variola virus F1L is a Bcl-2-like protein that unlike its vaccinia virus counterpart inhibits apoptosis independent of Bim.

    PubMed

    Marshall, B; Puthalakath, H; Caria, S; Chugh, S; Doerflinger, M; Colman, P M; Kvansakul, M

    2015-03-12

    Subversion of host cell apoptosis is an important survival strategy for viruses to ensure their own proliferation and survival. Certain viruses express proteins homologous in sequence, structure and function to mammalian pro-survival B-cell lymphoma 2 (Bcl-2) proteins, which prevent rapid clearance of infected host cells. In vaccinia virus (VV), the virulence factor F1L was shown to be a potent inhibitor of apoptosis that functions primarily be engaging pro-apoptotic Bim. Variola virus (VAR), the causative agent of smallpox, harbors a homolog of F1L of unknown function. We show that VAR F1L is a potent inhibitor of apoptosis, and unlike all other characterized anti-apoptotic Bcl-2 family members lacks affinity for the Bim Bcl-2 homology 3 (BH3) domain. Instead, VAR F1L engages Bid BH3 as well as Bak and Bax BH3 domains. Unlike its VV homolog, variola F1L only protects against Bax-mediated apoptosis in cellular assays. Crystal structures of variola F1L bound to Bid and Bak BH3 domains reveal that variola F1L forms a domain-swapped Bcl-2 fold, which accommodates Bid and Bak BH3 in the canonical Bcl-2-binding groove, in a manner similar to VV F1L. Despite the observed conservation of structure and sequence, variola F1L inhibits apoptosis using a startlingly different mechanism compared with its VV counterpart. Our results suggest that unlike during VV infection, Bim neutralization may not be required during VAR infection. As molecular determinants for the human-specific tropism of VAR remain essentially unknown, identification of a different mechanism of action and utilization of host factors used by a VAR virulence factor compared with its VV homolog suggest that studying VAR directly may be essential to understand its unique tropism.

  6. Chemosensitization of Prostate Cancer by Modulating Bcl-2 Family Proteins

    PubMed Central

    Karnak, David; Xu, Liang

    2010-01-01

    A major challenge in oncology is the development of chemoresistance. This often occurs as cancer progresses and malignant cells acquire mechanisms to resist insults that would normally induce apoptosis. The onset of androgen independence in advanced prostate cancer is a prime example of this phenomenon. Overexpression of the pro-survival/anti-apoptotic proteins Bcl-2, Bcl-xL, and Mcl-1 are hallmarks of this transition. Here we outline the evolution of therapeutics designed to either limit the source or disrupt the interactions of these pro-survival proteins. By either lessening the stoichiometric abundance of Bcl-2/xL/Mcl-1 in reference to their pro-apoptotic foils or freeing these pro-apoptotic proteins from their grip, these treatments aim to sensitize cells to chemotherapy by priming cells for death. DNA anti-sense and RNA interference have been effectively employed to decrease Bcl-2 family mRNA and protein levels in cell culture models of advanced prostate cancer. However, clinical studies are lagging due to in vivo delivery challenges. The burgeoning field of nanoparticle delivery holds great promise in helping to overcome the challenge of administering highly labile nucleic acid based therapeutics. On another front, small molecule inhibitors that block the hetero-dimerization of pro-survival with pro-apoptotic proteins have significant clinical advantages and have advanced farther in clinical trials with promising early results. Most recently, a peptide has been discovered that can convert Bcl-2 from a pro-survival to a pro-apoptotic protein. The future may lie in targeting multiple steps of the apoptotic pathway, including Bcl-2/xL/Mcl-1, to debilitate the survival capacity of cancer cells and make chemotherapy induced death their only option. PMID:20298153

  7. Effect of ginsenoside Rh-2 via activation of caspase-3 and Bcl-2-insensitive pathway in ovarian cancer cells.

    PubMed

    Kim, Jin Hee; Choi, Jae-Sun

    2016-12-13

    Ginsenoside has been reported to have therapeutic effects for some types of cancer, but its effect on ovarian cancer cells has not been evaluated. In this study, we monitored the effects of ginsenoside-Rh2 (Rh2) on the inhibition of cell proliferation and the apoptotic process in the ovarian cancer cell line SKOV3 using an MTT assay and TUNEL assay. We found that Rh2 inhibited cell proliferation and significantly induced apoptosis. We confirmed the apoptotic effects of Rh2 using western blot analysis of apoptosis-related proteins. Specifically, the levels of cleaved poly ADP ribose polymerase (PARP) and cleaved caspase-3 significantly increased in SKOV3 cells treated with Rh2. Therefore, Rh2 clearly suppressed the growth of SKOV3 cells in vitro, which was associated with induction of the apoptosis pathway. Moreover, the migration assay showed that Rh2 inhibited the invasive ability of SKOV3 cells. Taken together, our results suggest that Rh2 has anticancer effects in SKOV3 cells through inhibition of cell proliferation and induction of apoptosis. Considering the therapeutic potential of Rh2, more studies should be carried out to facilitate the future application of this natural product as a potential anti-cancer agent.

  8. Molecular and Computational Studies on Apoptotic Pathway Regulator, Bcl-2 Gene from Breast Cancer Cell Line MCF-7.

    PubMed

    Tiwari, Pragya; Khan, M J

    2016-01-01

    Cancer is a dreadful disease constituting abnormal growth and proliferation of malignant cells in the body. Next to lung cancer, breast cancer is the most common form of cancer affecting women. The apoptotic pathway regulators, B cell lymphoma family of protein, play a key role in various malignancies defining cancer and their constitutive expression plays an integral role in breast cancer chemotherapy. The research work discusses the identification and molecular cloning of a B cell lymphoma like gene from human breast cancer cell line. The open reading frame of the gene consisted of 965 nucleotides, encoding a protein of 380 amino acids with a predicted molecular weight of 42.5 kilodalton. The predicted physiochemical properties of the gene were as follows: Isoelectric point - 9.49, molecular formula - C1893H3004N534O548S16, total number of negatively charged residues, (Aspartate+Glutamate) - 26, total number of positively charged residues, (Arginine+Lysine)-39, instability index-42.08 (unstable protein) and grand average of hydropathicity is -0.202. Additionally, phobius prediction suggested non-cytoplasmic localization of the putative protein. The presence of secondary structure in the protein was determined by Memsat program. A 3 dimensional protein homology model was generated using threading based method of protein modeling for structural and functional annotation of the putative protein. Future prospects accounts for the biochemical characterization of the enzyme including in vitro assays on breast cancer cell line would establish the functional characteristics of the protein and its physiological mechanisms in breast cancer development and its therapeutic-target role in future.

  9. MicroRNA-497 Induces Apoptosis and Suppresses Proliferation via the Bcl-2/Bax-Caspase9-Caspase3 Pathway and Cyclin D2 Protein in HUVECs

    PubMed Central

    Wang, Mian; Xu, Xiangdong; Yao, Chen; Wang, Shenming

    2016-01-01

    Introduction MicroRNAs play crucial roles in various types of diseases. However, to date, no information about the role of miR-497 in the development of atherosclerosis has been reported. This study investigated the possible role of miR-497 in vascular endothelial cell injury during the early stage of atherosclerosis. Materials and Methods The expression level of miR-497 in human umbilical vein endothelial cells (HUVECs) exposed to ox-LDL was detected using qRT-PCR. To perform gain of function and loss of function analyses, miR-497 mimics were transfected into HUVECs, and miR-497 inhibitors were transfected into HUVECs stimulated with ox-LDL. Flow cytometry was used to analyze cell cycle progression and apoptosis. EdU and CCK-8 assays were employed to detect DNA synthesis and cell proliferation, respectively. After bioinformatics prediction, a dual Luciferase Reporter assay was used to analyze the direct target genes of miR-497. The mRNA and protein levels of the target genes were detected using qRT-PCR and western blot analyses, respectively. Caspase-9/3 activity was analyzed to determine the mechanism of endothelial dysfunction. Results We showed that miR-497 was significantly upregulated in HUVECs stimulated with ox-LDL. Ectopic expression of miR-497 suppressed cell proliferation, induced apoptosis and increased the activity of caspase-9/3. After verification, Bcl2 and CCND2 were shown to be direct target genes of miR-497 in HUVECs. MiR-497 significantly suppressed cell proliferation by arresting the cell cycle through the CCND2 protein and induced apoptosis through the Bcl2/Bax-caspase9-caspase3 pathway. Conclusion Overall, our study shows that miR-497 might play a role in the development of atherosclerosis by inducing apoptosis and suppressing the proliferation of vascular endothelial cells. Therefore, miR-497 could be a potential therapeutic target for the treatment of atherosclerosis. PMID:27918592

  10. Bcl-2 promotes malignant progression in a PDGF-B-dependent murine model of oligodendroglioma

    PubMed Central

    Doucette, Tiffany; Fuller, Gregory N.; Yang, Yuhui; Suki, Dima; Zhang, Wei; Fults, Daniel W.

    2011-01-01

    A significant subset of gliomas arises after activation of the pro-proliferative platelet-derived growth factor (PDGF) pathway. The progression of low-grade gliomas to more malignant tumors may be due to oncogenic cellular programs combining with those suppressing apoptosis. Anti-apoptotic genes are overexpressed in a variety of cancers and the anti-apoptotic gene, BCL2, is associated with treatment resistance and tumor recurrence in gliomas. However, the impact of anti-apoptotic gene expression to tumor formation and progression is unclear. We overexpressed Bcl-2 in a PDGFB-dependent mouse model of oligodendroglioma, a common glioma subtype, to assess its effect in vivo. We hypothesized that the anti-apoptotic effect would complement the pro-proliferative effect of PDGFB to promote tumor formation and progression to anaplastic oligodendroglioma (AO). Here, we show that co-expression of PDGFB and Bcl-2 results in a higher overall tumor formation rate compared to PDGFB alone. Co-expression of PDGFB and Bcl-2 promotes progression to AO with prominent foci of necrosis, a feature of high-grade gliomas. Median tumor latency was shorter in mice injected with PDGFB and Bcl-2 compared to those injected with PDGFB alone. Although independent expression of Bcl-2 was insufficient to induce tumors, suppression of apoptosis (detected by cleaved caspase-3 expression) was more pronounced in AOs induced by PDGFB and Bcl-2 compared to those induced by PDGFB alone. Tumor cell proliferation (detected by phosphohistone H3 activity) was also more robust in high-grade tumors induced by PDGFB and Bcl-2. Our results indicate that suppressed apoptosis enhances oligodendroglioma formation and engenders a more malignant phenotype. PMID:21171016

  11. Bcl-2 delays cell cycle through mitochondrial ATP and ROS.

    PubMed

    Du, Xing; Fu, Xufeng; Yao, Kun; Lan, Zhenwei; Xu, Hui; Cui, Qinghua; Yang, Elizabeth

    2017-02-22

    Bcl-2 inhibits cell proliferation by delaying G0/G1 to S phase entry. We tested the hypothesis that Bcl-2 regulates S phase entry through mitochondrial pathways. Existing evidence indicates mitochondrial adenosine tri-phosphate (ATP) and reactive oxygen species (ROS) are important signals in cell survival and cell death, however, the molecular details of how these 2 processes are linked remain unknown. In this study, 2 cell lines stably expressing Bcl-2, 3T3Bcl-2 and C3HBcl-2, and vector-alone PB controls were arrested in G0/G1 phase by serum starvation and contact inhibition, and ATP and ROS were measured during re-stimulation of cell cycle entry. Both ATP and ROS levels were decreased in G0/G1 arrested cells compared with normal growing cells. In addition, ROS levels were significant lower in synchronized Bcl-2 cells than those in PB controls. After re-stimulation, ATP levels increased with time, reaching peak value 1-3 hours ahead of S phase entry for both Bcl-2 cells and PB controls. Consistent with 2 hours of S phase delay, Bcl-2 cells reached ATP peaks 2 hours later than PB control, which suggests a rise in ATP levels is required for S phase entry. To examine the role of ATP and ROS in cell cycle regulation, ATP and ROS level were changed. We observed that elevation of ATP accelerated cell cycle progression in both PB and Bcl-2 cells, and decrease of ATP and ROS to the level equivalent to Bcl-2 cells delayed S phase entry in PB cells. Our results support the hypothesis that Bcl-2 protein regulates mitochondrial metabolism to produce less ATP and ROS, which contributes to S phase entry delay in Bcl-2 cells. These findings reveal a novel mechanistic basis for understanding the link between mitochondrial metabolism and tumor-suppressive function of Bcl-2.

  12. DNA Hypermethylation of CREB3L1 and Bcl-2 Associated with the Mitochondrial-Mediated Apoptosis via PI3K/Akt Pathway in Human BEAS-2B Cells Exposure to Silica Nanoparticles

    PubMed Central

    Zou, Yang; Li, Qiuling; Jiang, Lizhen; Guo, Caixia; Li, Yanbo; Yu, Yang; Li, Yang; Duan, Junchao; Sun, Zhiwei

    2016-01-01

    The toxic effects of silica nanoparticles (SiNPs) are raising concerns due to its widely applications in biomedicine. However, current information about the epigenetic toxicity of SiNPs is insufficient. In this study, the epigenetic regulation of low-dose exposure to SiNPs was evaluated in human bronchial epithelial BEAS-2B cells over 30 passages. Cell viability was decreased in a dose- and passage-dependent manner. The apoptotic rate, the expression of caspase-9 and caspase-3, were significantly increased induced by SiNPs. HumanMethylation450 BeadChip analysis identified that the PI3K/Akt as the primary apoptosis-related pathway among the 25 significant altered processes. The differentially methylated sites of PI3K/Akt pathway involved 32 differential genes promoters, in which the CREB3L1 and Bcl-2 were significant hypermethylated. The methyltransferase inhibitor, 5-aza, further verified that the DNA hypermethylation status of CREB3L1 and Bcl-2 were associated with downregulation of their mRNA levels. In addition, mitochondrial-mediated apoptosis was triggered by SiNPs via the downregulation of PI3K/Akt/CREB/Bcl-2 signaling pathway. Our findings suggest that long-term low-dose exposure to SiNPs could lead to epigenetic alterations. PMID:27362941

  13. Posttranslational regulation of BCL2 levels in cerebellar granule cells: A mechanism of neuronal survival.

    PubMed

    Lossi, Laura; Gambino, Graziana; Ferrini, Francesco; Alasia, Silvia; Merighi, Adalberto

    2009-11-01

    Apoptosis can be modulated by K(+) and Ca(2+) inside the cell and/or in the extracellular milieu. In murine organotypic cultures, membrane potential-regulated Ca(2+) signaling through calcineurin phosphatase has a pivotal role in development and maturation of cerebellar granule cells (CGCs). P8 cultures were used to analyze the levels of expression of B cell lymphoma 2 (BCL2) protein, and, after particle-mediated gene transfer in CGCs, to study the posttranslational modifications of BCL2 fused to a fluorescent tag in response to a perturbation of K(+)/Ca(2+) homeostasis. There are no changes in Bcl2 mRNA after real time PCR, whereas the levels of the fusion protein (monitored by calculating the density of transfected CGCs under the fluorescence microscope) and of BCL2 (inWestern blotting) are increased. After using a series of agonists/antagonists for ion channels at the cell membrane or the endoplasmic reticulum (ER), and drugs affecting protein synthesis/degradation, accumulation of BCL2 was related to a reduction in posttranslational cleavage by macroautophagy. The ER functionally links the [K(+)](e) and [Ca(2+)](i) to the BCL2 content in CGCs along two different pathways. The first, triggered by elevated [K(+)](e) under conditions of immaturity, is independent of extracellular Ca(2+) and operates via IP3 channels. The second leads to influx of extracellular Ca(2+) following activation of ryanodine channels in the presence of physiological [K(+)](e), when CGCs are maintained in mature status. This study identifies novel mechanisms of neuroprotection in immature and mature CGCs involving the posttranslational regulation of BCL2.

  14. The miR-573/apoM/Bcl2A1-dependent signal transduction pathway is essential for hepatocyte apoptosis and hepatocarcinogenesis.

    PubMed

    Hu, Yan-Wei; Chen, Zhi-Ping; Hu, Xiu-Mei; Zhao, Jia-Yi; Huang, Jin-Lan; Ma, Xin; Li, Shu-Fen; Qiu, Yu-Rong; Wu, Xiao-Juan; Sha, Yan-Hua; Gao, Ji-Juan; Wang, Yan-Chao; Zheng, Lei; Wang, Qian

    2015-10-01

    Hepatocellular carcinoma (HCC) is one of the most common malignant tumors with an increasing incidence worldwide. Apolipoprotein M (apoM) is a novel apolipoprotein that is mainly expressed in liver and kidney tissues. However, the anti-tumor properties of apoM remain largely unknown. We evaluated the anti-tumor activities and mechanisms of apoM in HCC both in vivo and in vitro. Bioinformatic analysis and luciferase reporter assay results showed that apoM was a potential target of hsa-miR-573 and was downregulated after transfection with hsa-miR-573 mimics. Overexpression of apoM suppressed migration, invasion, and proliferation of hepatoma cells in vitro. Overexpression of hsa-miR-573 in hepatoma cells reduced apoM expression, leading to promotion of the invasion, migration, and proliferation of hepatoma cells in vitro. In addition, hsa-miR-573 markedly promoted growth of xenograft tumors in nude mice with an accompanying reduction in cell apoptosis. ApoM markedly inhibited growth of xenograft tumors in nude mice and promoted cell apoptosis. Moreover, Bcl2A1 mRNA and protein levels were inhibited by apoM overexpression and an increase in apoptosis rate by apoM was markedly compensated by Bcl2A1 overexpression in HepG2 cells. These results provide evidence that hsa-miR-573 promoted tumor growth by inhibition of hepatocyte apoptosis and this pro-tumor effect might be mediated through Bcl2A1 in an apoM-dependent manner. Therefore, our findings may be useful to improve understanding of the critical effects of hsa-miR-573 and apoM in HCC pathogenesis.

  15. Targeting the Bcl-2 Family for Cancer Therapy

    PubMed Central

    Thomas, Shibu; Quinn, Bridget A.; Das, Swadesh K.; Dash, Rupesh; Emdad, Luni; Dasgupta, Santanu; Wang, Xiang-Yang; Dent, Paul; Reed, John C.; Pellecchia, Maurizio; Sarkar, Devanand; Fisher, Paul B.

    2014-01-01

    Introduction Programmed cell death is well-orchestrated process regulated by multiple pro-apoptotic and anti-apoptotic genes, particularly those of the Bcl-2 gene family. These genes are well documented in cancer with aberrant expression being strongly associated with resistance to chemotherapy and radiation. Areas covered This review focuses on the resistance induced by the Bcl-2 family of anti-apoptotic proteins and current therapeutic interventions currently in preclinical or clinical trials that target this pathway. Major resistance mechanisms that are regulated by Bcl-2 family proteins and potential strategies to circumvent resistance are also examined. Although antisense and gene therapy strategies are used to nullify Bcl-2 family proteins, recent approaches use small molecule inhibitors and peptides. Structural similarity of the Bcl-2 family of proteins greatly favors development of inhibitors that target the BH3 domain, called BH3 mimetics. Expert opinion Strategies to specifically identify and inhibit critical determinants that promote therapy-resistance and tumor progression represent viable approaches for developing effective cancer therapies. From a clinical perspective, pretreatment with novel, potent Bcl-2 inhibitors either alone or in combination with conventional therapies hold significant promise for providing beneficial clinical outcomes. Identifying small molecule inhibitors with broader and higher affinities for inhibiting all of the Bcl-2 pro-survival proteins will facilitate development of superior cancer therapies. PMID:23173842

  16. Hepatitis C Virus Nonstructural 5A Protein (HCV-NS5A) Inhibits Hepatocyte Apoptosis through the NF-κb/miR-503/bcl-2 Pathway

    PubMed Central

    Xie, Zhengyuan; Xiao, Zhihua; Wang, Fenfen

    2017-01-01

    The nonstructural protein 5A (NS5A) encoded by the human hepatitis C virus (HCV) RNA genome is a multifunctional phosphoprotein. To analyse the influence of NS5A on apoptosis, we established an Hep-NS5A cell line (HepG2 cells that stably express NS5A) and induced apoptosis using tumour necrosis factor (TNF)-α. We utilised the MTT assay to detect cell viability, real-time quantitative polymerase chain reaction and Western blot to analyse gene and protein expression, and a luciferase reporter gene experiment to investigate the targeted regulatory relationship. Chromatin immunoprecipitation was used to identify the combination of NF-κB and miR-503. We found that overexpression of NS5A inhibited TNF-αinduced hepatocellular apoptosis via regulating miR-503 expression. The cell viability of the TNF-α induced Hep-mock cells was significantly less than the viability of the TNF-α induced Hep-NS5A cells, which demonstrates that NS5A inhibited TNF-α-induced HepG2 cell apoptosis. Under TNF-α treatment, miR-503 expression was decreased and cell viability and B-cell lymphoma 2 (bcl-2) expression were increased in the Hep-NS5A cells. Moreover, the luciferase reporter gene experiment verified that bcl-2 was a direct target of miR-503, NS5A inhibited TNF-α-induced NF-κB activation and NF-κB regulated miR-503 transcription by combining with the miR-503 promoter. After the Hep-NS5A cells were transfected with miR-503 mimics, the data indicated that the mimics could reverse TNF-α-induced cell apoptosis and blc-2 expression. Collectively, our findings suggest a possible molecular mechanism that may contribute to HCV treatment in which NS5A inhibits NF-κB activation to decrease miR-503 expression and increase bcl-2 expression, which leads to a decrease in hepatocellular apoptosis. PMID:28343379

  17. BET Inhibition Induces Apoptosis in Aggressive B-Cell Lymphoma via Epigenetic Regulation of BCL-2 Family Members.

    PubMed

    Hogg, Simon J; Newbold, Andrea; Vervoort, Stephin J; Cluse, Leonie A; Martin, Benjamin P; Gregory, Gareth P; Lefebure, Marcus; Vidacs, Eva; Tothill, Richard W; Bradner, James E; Shortt, Jake; Johnstone, Ricky W

    2016-09-01

    Targeting BET bromodomain proteins using small molecules is an emerging anticancer strategy with clinical evaluation of at least six inhibitors now underway. Although MYC downregulation was initially proposed as a key mechanistic property of BET inhibitors, recent evidence suggests that additional antitumor activities are important. Using the Eμ-Myc model of B-cell lymphoma, we demonstrate that BET inhibition with JQ1 is a potent inducer of p53-independent apoptosis that occurs in the absence of effects on Myc gene expression. JQ1 skews the expression of proapoptotic (Bim) and antiapoptotic (BCL-2/BCL-xL) BCL-2 family members to directly engage the mitochondrial apoptotic pathway. Consistent with this, Bim knockout or Bcl-2 overexpression inhibited apoptosis induction by JQ1. We identified lymphomas that were either intrinsically resistant to JQ1-mediated death or acquired resistance following in vivo exposure. Strikingly, in both instances BCL-2 was strongly upregulated and was concomitant with activation of RAS pathways. Eμ-Myc lymphomas engineered to express activated Nras upregulated BCL-2 and acquired a JQ1 resistance phenotype. These studies provide important information on mechanisms of apoptosis induction and resistance to BET-inhibition, while providing further rationale for the translation of BET inhibitors in aggressive B-cell lymphomas. Mol Cancer Ther; 15(9); 2030-41. ©2016 AACR.

  18. miR-204 targets Bcl-2 expression and enhances responsiveness of gastric cancer

    PubMed Central

    Sacconi, A; Biagioni, F; Canu, V; Mori, F; Di Benedetto, A; Lorenzon, L; Ercolani, C; Di Agostino, S; Cambria, A M; Germoni, S; Grasso, G; Blandino, R; Panebianco, V; Ziparo, V; Federici, O; Muti, P; Strano, S; Carboni, F; Mottolese, M; Diodoro, M; Pescarmona, E; Garofalo, A; Blandino, G

    2012-01-01

    Micro RNAs (miRs) are small non-coding RNAs aberrantly expressed in human tumors. Here, we aim to identify miRs whose deregulated expression leads to the activation of oncogenic pathways in human gastric cancers (GCs). Thirty nine out of 123 tumoral and matched uninvolved peritumoral gastric specimens from three independent European subsets of patients were analyzed for the expression of 851 human miRs using Agilent Platform. The remaining 84 samples were used to validate miRs differentially expressed between tumoral and matched peritumoral specimens by qPCR. miR-204 falls into a group of eight miRs differentially expressed between tumoral and peritumoral samples. Downregulation of miR-204 has prognostic value and correlates with increased staining of Bcl-2 protein in tumoral specimens. Ectopic expression of miR-204 inhibited colony forming ability, migration and tumor engraftment of GC cells. miR-204 targeted Bcl-2 messenger RNA and increased responsiveness of GC cells to 5-fluorouracil and oxaliplatin treatment. Ectopic expression of Bcl-2 protein counteracted miR-204 pro-apoptotic activity in response to 5-fluorouracil. Altogether, these findings suggest that modulation of aberrant expression of miR-204, which in turn releases oncogenic Bcl-2 protein activity might hold promise for preventive and therapeutic strategies of GC. PMID:23152059

  19. BRCA1 involved in regulation of Bcl-2 expression and apoptosis susceptibility to ionizing radiation

    NASA Astrophysics Data System (ADS)

    Wang, YanLing; Wang, Bing; Zhang, Hong; Li, Ning; Tanaka, Kaoru; Zhou, Xin; Chen, RuPing; Zhang, Xin

    2011-05-01

    BRCA1 has been proposed to be tightly linked to the resistance of tumor cells to ionizing radiation. The pathway leading to this phenomenon is not yet clear. In this work, we investigated the role of BRCA1 in the apoptosis regulation in response to carbon ion irradiation. We utilized three different cancer cell lines with various states for BRCA1 and p53 to identify the relationship between endogenous BRCA1 and the apoptosis-related genes, and determine whether p53 function would affect the role of BRCA1 in apoptosis regulation. By Western blot analysis, we found that Bax expressions were not significantly changed after irradiation in all of three cell lines. However, Bcl-2 expression showed an up-regulation by endogenous BRCA1 regardless of p53 status. Moreover, the changes in Bcl-2 protein were due to the increase in the transcriptional levels of Bcl-2 mRNA, based on real-time PCR assay. At the same time, BRCA1-deficient cells showed a greater apoptosis susceptibility to irradiation when compared with BRCA1-proficient cells. The results suggest that BRCA1 might exert p53-independent regulative activities for Bcl-2, which seems account for the low apoptosis susceptibility in BRCA1-proficient carcinomas.

  20. NHE9 induces chemoradiotherapy resistance in esophageal squamous cell carcinoma by upregulating the Src/Akt/β-catenin pathway and Bcl-2 expression

    PubMed Central

    Chen, Junying; Yang, Hong; Wen, Jing; Luo, Kongjia; Liu, Qianwen; Huang, Yijie; Zheng, Yuzhen; Tan, Zihui; Qingyuan Huang, Qinyuan; Fu, Jianhua

    2015-01-01

    Recently, we found that NHE9 mRNA was upregulated in chemoradiotherapy (CRT)-resistant esophageal squamous cell carcinoma (ESCC); however, the underlying mechanisms were unclear. Here, we aimed to clarify the functional contribution of NHE9 to CRT resistance, understand the molecular basis of NHE9-dependent resistance in ESCC, and identify potential therapeutic targets. Our results showed that NHE9 prevented CRT-induced apoptosis. Importantly, we found that RACK1 is a novel binding partner of NHE9 and that NHE9-dependent induction of CRT resistance requires the activation of RACK1-associated Src/Akt/β-catenin signaling. Moreover, upregulated Bcl-2 protein was also observed in cells exhibiting NHE9-induced CRT resistance. A higher NHE9 level was associated with a poor response to CRT and less decrease in T and N stage in ESCC patients. Furthermore, combining either Dasatinib or ABT-737 with CRT significantly reduced tumor volume, and the response to CRT was restored when these inhibitors were used together with CRT in a xenograft nude mouse model with NHE9 overexpression. Taken together, our findings demonstrate that NHE9 can be an effective predictor of CRT response and may be useful in the development of targeted therapies for CRT-resistant ESCC. PMID:25915159

  1. Sphallerocarpus gracilis polysaccharide protects pancreatic β-cells via regulation of the bax/bcl-2, caspase-3, pdx-1 and insulin signalling pathways.

    PubMed

    Guo, Jie; Wang, Junlong; Song, Shen; Liu, Qin; Huang, Yulong; Xu, Yunfei; Wei, YanXia; Zhang, Ji

    2016-12-01

    In this study, the structural characterization of Sphallerocarpus gracilis polysaccharide (SGP) and its hypoglycaemic activities are reported for the first time. SGP, which has a weight average molar mass (Mw) of 7.413×10(5), was isolated from Sphallerocarpus gracilis and purified by ion-exchange chromatography. The polysaccharide is composed of rhamnose, arabinose, mannose, glucose and galactose, with the molar ratio of 4.12: 8.99: 5.45: 65.94: 15.50. The mechanism underlying the hypoglycaemic effect of SGP was evaluated. Experimental results showed that SGP protected pancreatic β-cells from alloxan damage by several possible mechanisms, including: (1) repairing free radical damage; (2) reducing the apoptosis of pancreatic β-cells by inhibiting the activities of caspase-3 and bax, and enhancing the activity of bcl-2; (3) stimulating insulin secretion and upregulating the pancreatic and duodenal homeobox 1 gene and the insulin gene and the pancreatic in pancreatic β-cells. The results obtained in this study suggest that SGP may be a promising therapeutic agent in the treatment of diabetes mellitus.

  2. Bcl-2 is a critical mediator of intestinal transformation

    PubMed Central

    van der Heijden, Maartje; Zimberlin, Cheryl D.; Nicholson, Anna M.; Colak, Selcuk; Kemp, Richard; Meijer, Sybren L.; Medema, Jan Paul; Greten, Florian R.; Jansen, Marnix; Winton, Douglas J.; Vermeulen, Louis

    2016-01-01

    Intestinal tumour formation is generally thought to occur following mutational events in the stem cell pool. However, active NF-κB signalling additionally facilitates malignant transformation of differentiated cells. We hypothesized that genes shared between NF-κB and intestinal stem cell (ISCs) signatures might identify common pathways that are required for malignant growth. Here, we find that the NF-κB target Bcl-2, an anti-apoptotic gene, is specifically expressed in ISCs in both mice and humans. Bcl-2 is dispensable in homeostasis and, although involved in protecting ISCs from radiation-induced damage, it is non-essential in tissue regeneration. Bcl-2 is upregulated in adenomas, and its loss or inhibition impairs outgrowth of oncogenic clones, because Bcl-2 alleviates apoptotic priming in epithelial cells following Apc loss. Furthermore, Bcl-2 expression in differentiated epithelial cells renders these cells amenable to clonogenic outgrowth. Collectively, our results indicate that Bcl-2 is required for efficient intestinal transformation following Apc-loss and constitutes a potential chemoprevention target. PMID:26956214

  3. Intranasal Administration of Interferon Beta Attenuates Neuronal Apoptosis via the JAK1/STAT3/BCL-2 Pathway in a Rat Model of Neonatal Hypoxic-Ischemic Encephalopathy

    PubMed Central

    Dixon, Brandon J.; Chen, Di; Zhang, Yang; Flores, Jerry; Malaguit, Jay; Nowrangi, Derek; Zhang, John H.

    2016-01-01

    Neonatal hypoxic-ischemic encephalopathy (HIE) is an injury that often leads to detrimental neurological deficits. Currently, there are no established therapies for HIE and it is critical to develop treatments that provide protection after HIE. The objective of this study was to investigate the ability of interferon beta (IFNβ) to provide neuroprotection and reduce apoptosis after HIE. Postnatal Day 10 rat pups were subjected to unilateral carotid artery ligation followed by 2.5 hr of exposure to hypoxia (8% O2). Intranasal administration of human recombinant IFNβ occurred 2 hr after HIE and infarct volume, body weight, neurobehavioral tests, histology, immunohistochemistry, brain water content, blood–brain barrier permeability, enzyme-linked immunosorbent assay, and Western blot were all used to evaluate various parameters. The results showed that both IFNβ and the Type 1 interferon receptor expression decreases after HIE. Intranasal administration of human recombinant IFNβ was able to be detected in the central nervous system and was able to reduce brain infarction volumes and improve neurological behavior tests 24 hr after HIE. Western blot analysis also revealed that human recombinant IFNβ treatment stimulated Stat3 and Bcl-2 expression leading to a decrease in cleaved caspase-3 expression after HIE. Positive Fluoro-Jade C staining also demonstrated that IFNβ treatment was able to decrease neuronal apoptosis. Furthermore, the beneficial effects of IFNβ treatment were reversed when a Stat3 inhibitor was applied. Also an intraperitoneal administration of human recombinant IFNβ into the systemic compartment was unable to confer the same protective effects as intranasal IFNβ treatment. PMID:27683877

  4. Bcl-2–Mediated Drug Resistance

    PubMed Central

    Srivastava, Rakesh K.; Sasaki, Carl Y.; Hardwick, J. Marie; Longo, Dan L.

    1999-01-01

    Bcl-2 inhibits apoptosis induced by a variety of stimuli, including chemotherapy drugs and glucocorticoids. It is generally accepted that Bcl-2 exerts its antiapoptotic effects mainly by dimerizing with proapoptotic members of the Bcl-2 family such as Bax and Bad. However, the mechanism of the antiapoptotic effects is unclear. Paclitaxel and other drugs that disturb microtubule dynamics kill cells in a Fas/Fas ligand (FasL)-dependent manner; antibody to FasL inhibits paclitaxel-induced apoptosis. We have found that Bcl-2 overexpression leads to the prevention of chemotherapy (paclitaxel)-induced expression of FasL and blocks paclitaxel-induced apoptosis. The mechanism of this effect is that Bcl-2 prevents the nuclear translocation of NFAT (nuclear factor of activated T lymphocytes, a transcription factor activated by microtubule damage) by binding and sequestering calcineurin, a calcium-dependent phosphatase that must dephosphorylate NFAT to move to the nucleus. Without NFAT nuclear translocation, the FasL gene is not transcribed. Thus, it appears that paclitaxel and other drugs that disturb microtubule function kill cells at least in part through the induction of FasL. Furthermore, Bcl-2 antagonizes drug-induced apoptosis by inhibiting calcineurin activation, blocking NFAT nuclear translocation, and preventing FasL expression. The effects of Bcl-2 can be overcome, at least partially, through phosphorylation of Bcl-2. Phosphorylated Bcl-2 cannot bind calcineurin, and NFAT activation, FasL expression, and apoptosis can occur after Bcl-2 phosphorylation. PMID:10432288

  5. Bcl-2 expression is a poor predictor for hepatocellular carcinoma prognosis of andropause-age patients

    PubMed Central

    Zhang, Xiao-Fei; Yang, Xin; Jia, Hu-Liang; Zhu, Wen-Wei; Lu, Lu; Shi, Wei; Zhang, Hao; Chen, Jin-Hong; Tao, Yi-Feng; Wang, Zheng-Xin; Yang, Jun; Wang, Lian-Xin; Lu, Ming; Zheng, Yan; Zhao, Jing; Dong, Qiong-Zhu; Qin, Lun-Xiu

    2016-01-01

    Objective: The expression of B-cell lymphoma 2 (Bcl-2) seems to be influenced by the endocrine environment. Numerous reports demonstrate the diverse expression of Bcl-2 family members under sex steroid regulation. With the exception of estrogen-related tumors, androgen-related tumors have shown their characteristics in Bcl-2 expression. In this study, the status of Bcl-2 expression in male hepatocellular carcinoma (HCC) patients was examined to verify the high incidence of HCC in males. Methods: Tumor tissue microarray was used to examine Bcl-2 expression levels in 374 HCC cases including 306 males and 68 females. Kaplan-Meier method, log-rank test, and Cox proportional hazards model were applied to investigate the predictive value of Bcl-2 in HCC patients. Results: Immunohistochemistry analysis showed that male patients with higher Bcl-2 levels had significantly longer median survival time and recurrence time than those with lower levels. However, no significant differences in outcomes were found between different Bcl-2 levels in female patients. When the male patients were stratified into several age points, the level of Bcl-2 expression showed poorer predictive efficiency in the 45–49 and 55–60 age groups in andropause-age patients compared with other age groups. Bcl-2 was an independent prognostic factor for both overall survival (P < 0.0001) and recurrence time (P = 0.0001) in male patients. After excluding male patients in the 45–60 age group, the predictive efficiency was enhanced (n = 147, OS, P = 0.0002, TTR, P < 0.0001). Conclusions: Bcl-2 expression is an independent predictor of survival and recurrence in male HCC. Bcl-2 levels may also be regulated by androgens or androgen receptors in male HCC patients. Bcl-2 levels change and exhibit poor predictive efficiency when androgen levels vary dramatically (andropause age). PMID:28154777

  6. Bcl-2 expression in synovial fibroblasts is essential for maintaining mitochondrial homeostasis and cell viability.

    PubMed

    Perlman, H; Georganas, C; Pagliari, L J; Koch, A E; Haines, K; Pope, R M

    2000-05-15

    The regulation of proliferation and cell death is vital for homeostasis, but the mechanism that coordinately balances these events in rheumatoid arthritis (RA) remains largely unknown. In RA, the synovial lining thickens in part through increased proliferation and/or decreased synovial fibroblast cell death. Here we demonstrate that the anti-apoptotic protein, Bcl-2, is highly expressed in RA compared with osteoarthritis synovial tissues, particularly in the CD68-negative, fibroblast-like synoviocyte population. To determine the importance of endogenous Bcl-2, an adenoviral vector expressing a hammerhead ribozyme to Bcl-2 (Ad-Rbz-Bcl-2) mRNA was employed. Ad-Rbz-Bcl-2 infection resulted in reduced Bcl-2 expression and cell viability in synovial fibroblasts isolated from RA and osteoarthritis synovial tissues. In addition, Ad-Rbz-Bcl-2-induced mitochondrial permeability transition, cytochrome c release, activation of caspases 9 and 3, and DNA fragmentation. The general caspase inhibitor zVAD.fmk blocked caspase activation, poly(ADP-ribose) polymerase cleavage, and DNA fragmentation, but not loss of transmembrane potential or viability, indicating that cell death was independent of caspase activation. Ectopically expressed Bcl-xL inhibited Ad-Rbz-Bcl-2-induced mitochondrial permeability transition and apoptosis in Ad-Rbz-Bcl-2-transduced cells. Thus, forced down-regulation of Bcl-2 does not induce a compensatory mechanism to prevent loss of mitochondrial integrity and cell death in human fibroblasts.

  7. 17-DMAG Diminishes Hemorrhage-Induced Small Intestine Injury by Elevating Bcl-2 Protein and Inhibiting iNOS Pathway, TNF-alpha Increase, and Caspase-3 Activation

    DTIC Science & Technology

    2011-06-03

    Hemorrhagic shock has been shown to cause systemic inflammation response syndrome (SIRS), multiple organ dysfunction syndrome (MODS), and multiple organ...available to tissues and results in an accumulation of carbon dioxide and metabolic waste , leading to activation of signal transduction pathways and...for each specimen was graded using a six-tiered scale [3]. Western blots. Jejunal tissue was minced in 100 µl Hanks’ balanced salt solution

  8. Bcl-2 inhibitors potentiate the cytotoxic effects of radiation in Bcl-2 overexpressing radioresistant tumor cells

    SciTech Connect

    Hara, Takamitsu; Omura-Minamisawa, Motoko . E-mail: momuram@med.yokohama-cu.ac.jp; Chao Cheng; Nakagami, Yoshihiro; Ito, Megumi; Inoue, Tomio

    2005-02-01

    Purpose: Bcl-2, an inhibitor of apoptosis frequently shows elevated expression in human tumors, thus resulting in resistance to radiation therapy. Therefore, inhibiting Bcl-2 function may enhance the radiosensitivity of tumor cells. Tetrocarcin A (TC-A) and bcl-2 antisense oligonucleotides exhibit antitumor activity by inhibiting Bcl-2 function and transcription, respectively. We investigated whether these antitumor agents would enhance the cytotoxic effects of radiation in tumor cells overexpressing Bcl-2. Methods and materials: We used HeLa/bcl-2 cells, a stable Bcl-2-expressing cell line derived from wild-type HeLa (HeLa/wt) cells. Cells were incubated with TC-A and bcl-2 antisense oligonucleotides for 24 h after irradiation, and cell viability was then determined. Apoptotic cells were quantified by flow cytometric assay. Results: The HeLa/bcl-2 cells were more resistant to radiation than HeLa/wt cells. At concentrations that are not inherently cytotoxic, both TC-A and bcl-2 antisense oligonucleotides increased the cytotoxic effects of radiation in HeLa/bcl-2 cells, but not in HeLa/wt cells. However, in HeLa/bcl-2 cells, additional treatment with TC-A in combination with radiation did not significantly increase apoptosis. Conclusions: The present results suggest that TC-A and bcl-2 antisense oligonucleotides reduce radioresistance of tumor cells overexpressing Bcl-2. Therefore, a combination of radiotherapy and Bcl-2 inhibitors may prove to be a useful therapeutic approach for treating tumors that overexpress Bcl-2.

  9. Influence of p53 and bcl-2 on chemosensitivity in benign and malignant prostatic cell lines.

    PubMed

    Serafin, Antonio M; Bohm, Lothar

    2005-01-01

    The administration of cancer chemotherapeutic agents results in an increase in the apoptotic cells in the tumor: therefore, it has been assumed that anticancer drugs exhibit their cytotoxic effects via apoptotic signaling pathways. Characteristics that confer sensitivity to drug-induced apoptosis are, a functional p53 protein and expression of the apoptosis-promoting protein, bax. The role of p53 and bax/bcl-2 in drug-induced apoptosis was assessed in six prostate cell lines, 1532T, 1535T, 1542T, 1542N, BPH-1 and LNCaP using TD(50) concentrations of etoposide, vinblastine and estramustine. Cell death was monitored morphologically by fluorescent microscopy, and by flow cytometry (Annexin-V assay). Apoptotic morphology was rather low and ranged from 0.1% to 12.1%, 3.0% to 6.0% and 0.1% to 8.5% for etoposide, estramustine and vinblastine, respectively. Annexin-V binding and flow cytometry indicated apoptotic propensities of 0% to 4%, 0% to 3% and 0% to 5%, respectively. The percentage of cells responding to drug-induced apoptosis was, on average, higher in the tumor cell lines than in the normal cell lines, but showed no correlation with p53 status. The percentage of cells showing necrosis, assessed by Annexin binding and Propidium Iodide permeability in aqueous medium, tended to be much higher, and was found to be at the level of 5% to 30%. Immunoblotting demonstrated that bax and bcl-2 proteins were expressed at a basal level in all cell lines, but did not increase after exposure to TD(50) doses of the three drugs. The ratio of bax and bcl-2, measured by laser scanning densitometry, was not altered by the drug-induced DNA damage. The results suggest that apoptosis is not a major mechanism of drug-induced cell death in prostate cell lines and appears to be independent of p53 status and bax/bcl-2 expression.

  10. Bcl-2 apoptosis proteins, mitochondrial membrane curvature, and cancer

    NASA Astrophysics Data System (ADS)

    Hwee Lai, Ghee; Schmidt, Nathan; Sanders, Lori; Mishra, Abhijit; Wong, Gerard; Ivashyna, Olena; Christenson, Eric; Schlesinger, Paul; Akabori, Kiyotaka; Santangelo, Christian

    2012-02-01

    Critical interactions between Bcl-2 family proteins permeabilize the outer mitochondrial membrane, a common decision point early in the intrinsic apoptotic pathway that irreversibly commits the cell to death. However, a unified picture integrating the essential non-passive role of lipid membranes with the contested dynamics of Bcl-2 regulation remains unresolved. Correlating results between synchrotron x-ray diffraction and microscopy in cell-free assays, we report activation of pro-apoptotic Bax induces strong pure negative Gaussian membrane curvature topologically necessary for pore formation and membrane remodeling events. Strikingly, Bcl-xL suppresses not only Bax-induced pore formation, but also membrane remodeling by disparate systems including cell penetrating, antimicrobial or viral fusion peptides, and bacterial toxin, none of which have BH3 allosteric domains to mediate direct binding. We propose a parallel mode of Bcl-2 pore regulation in which Bax and Bcl-xL induce antagonistic and mutually interacting Gaussian membrane curvatures. The universal nature of curvature-mediated interactions allows synergy with direct binding mechanisms, and potentially accounts for the Bcl-2 family modulation of mitochondrial fission/fusion dynamics.

  11. New insights in the role of Bcl-2 Bcl-2 and the endoplasmic reticulum.

    PubMed

    Rudner, J; Jendrossek, V; Belka, C

    2002-10-01

    The oncogenic protein Bcl-2 which is expressed in membranes of different subcellular organelles protects cells from apoptosis induced by endogenic stimuli. Most of the results published so far emphasise the importance of Bcl-2 at the mitochondria. Several recent observations suggest a role of Bcl-2 at the endoplasmic reticulum (ER). Bcl-2 located at the ER was shown to interfere with apoptosis induction by Bax, ceramides, ionising radiation, serum withdrawal and c-myc expression. Although the detailed functions of Bcl-2 at the ER remain elusive, several speculative mechanisms may be supposed. For instance, Bcl-2 at the ER may regulate calcium fluxes between the ER and the mitochondria. In addition, Bcl-2 is able to interact with the endoplasmic protein Bap31 thus avoiding caspase activation at the ER. Bcl-2 may also abrogate the function of ER located pro-apoptotic Bcl-2 like proteins by heterodimerization. Current data on the function of Bcl-2 at the ER, its role for the modulation of calcium fluxes and its influence on caspase activation at the ER are reviewed.

  12. Antisense bcl-2 treatment increases programmed cell death in non-small cell lung cancer cell lines.

    PubMed

    Koty, P P; Zhang, H; Levitt, M L

    1999-02-01

    Programmed cell death (PCD) is a genetically regulated pathway that is altered in many cancers. This process is, in part, regulated by the ratio of PCD inducers (Bax) or inhibitors (Bcl-2). An abnormally high ratio of Bcl-2 to Bax prevents PCD, thus contributing to resistance to chemotherapeutic agents, many of which are capable of inducing PCD. Non-small cell lung cancer (NSCLC) cells demonstrate resistance to these PCD-inducing agents. If Bcl-2 prevents NSCLC cells from entering the PCD pathway, then reducing the amount of endogenous Bcl-2 product may allow these cells to spontaneously enter the PCD pathway. Our purpose was to determine the effects of bcl-2 antisense treatment on the levels of programmed cell death in NSCLC cells. First, we determined whether bcl-2 and bax mRNA were expressed in three morphologically distinct NSCLC cell lines: NCI-H226 (squamous), NCI-H358 (adenocarcinoma), and NCI-H596 (adenosquamous). Cells were then exposed to synthetic antisense bcl-2 oligonucleotide treatment, after which programmed cell death was determined, as evidenced by DNA fragmentation. Bcl-2 protein expression was detected immunohistochemically. All three NSCLC cell lines expressed both bcl-2 and bax mRNA and had functional PCD pathways. Synthetic antisense bcl-2 oligonucleotide treatment resulted in decreased Bcl-2 levels, reduced cell proliferation, decreased cell viability, and increased levels of spontaneous PCD. This represents the first evidence that decreasing Bcl-2 in three morphologically distinct NSCLC cell lines allows the cells to spontaneously enter a PCD pathway. It also indicates the potential therapeutic use of antisense bcl-2 in the treatment of NSCLC.

  13. Yeast as a tool for studying proteins of the Bcl-2 family.

    PubMed

    Polčic, Peter; Jaká, Petra; Mentel, Marek

    2015-03-02

    Permeabilization of the outer mitochondrial membrane that leads to the release of cytochrome c and several other apoptogenic proteins from mitochondria into cytosol represents a commitment point of apoptotic pathway in mammalian cells. This crucial event is governed by proteins of the Bcl-2 family. Molecular mechanisms, by which Bcl-2 family proteins permeabilize mitochondrial membrane, remain under dispute. Although yeast does not have apparent homologues of these proteins, when mammalian members of Bcl-2 family are expressed in yeast, they retain their activity, making yeast an attractive model system, in which to study their action. This review focuses on using yeast expressing mammalian proteins of the Bcl-2 family as a tool to investigate mechanisms, by which these proteins permeabilize mitochondrial membranes, mechanisms, by which pro- and antiapoptotic members of this family interact, and involvement of other cellular components in the regulation of programmed cell death by Bcl-2 family proteins.

  14. Yeast as a tool for studying proteins of the Bcl-2 family

    PubMed Central

    Polčic, Peter; Jaká, Petra; Mentel, Marek

    2015-01-01

    Permeabilization of the outer mitochondrial membrane that leads to the release of cytochrome c and several other apoptogenic proteins from mitochondria into cytosol represents a commitment point of apoptotic pathway in mammalian cells. This crucial event is governed by proteins of the Bcl-2 family. Molecular mechanisms, by which Bcl-2 family proteins permeabilize mitochondrial membrane, remain under dispute. Although yeast does not have apparent homologues of these proteins, when mammalian members of Bcl-2 family are expressed in yeast, they retain their activity, making yeast an attractive model system, in which to study their action. This review focuses on using yeast expressing mammalian proteins of the Bcl-2 family as a tool to investigate mechanisms, by which these proteins permeabilize mitochondrial membranes, mechanisms, by which pro- and antiapoptotic members of this family interact, and involvement of other cellular components in the regulation of programmed cell death by Bcl-2 family proteins. PMID:28357280

  15. Structural biology of the Bcl-2 family and its mimicry by viral proteins

    PubMed Central

    Kvansakul, M; Hinds, M G

    2013-01-01

    lead to differences in behavior, and together with the intrinsic structural plasticity in the Bcl-2 fold enable exquisite control over critical cellular signaling pathways. PMID:24201808

  16. Curcumin induces p53-independent necrosis in H1299 cells via a mitochondria-associated pathway.

    PubMed

    Li, Feie; Chen, Xi; Xu, Bing; Zhou, Hua

    2015-11-01

    Curcumin has been shown to have various therapeutic and/or adjuvant therapeutic effects on human cancers, as it inhibits cancer cell proliferation and induces apoptosis through p53-dependent molecular pathways. However, numerous cancer cell types bear a mutant p53 gene, and whether curcumin has any therapeutic effects on p53-deficient/mutant cancer cells has remained elusive. The present study sought to determine whether curcumin exerts any anti-proliferative and cytotoxic effects on the p53-deficient H1299 human lung cancer cell line via a p53-independent mechanism. An MTT assay and flow cytometric analysis indicated that curcumin significantly decreased cell proliferation and induced necrotic cell death. Western blot analysis of the cytosolic and mitochondrial fractions of H1299 cells as well as a fluorometric caspase assay indicated that curcumin-induced necrosis was mitochondria- and caspase-dependent, and resulted in cytochrome c release. Of note, this necrotic cell death was reduced following inhibition of B-cell lymphoma‑2 (Bcl-2)‑associated X protein (Bax) or Bcl‑2 homologous antagonist killer (Bak) as well as overexpression of Bcl-2. In conclusion, the present study suggested that curcumin-induced necrotic cell death was mediated via a p53-independent molecular pathway, which was associated with Bax and Bak translocation, caspase activation and cytochrome c release.

  17. Prognostic value of bcl-2 expression among women with breast cancer in Libya.

    PubMed

    Ermiah, Eramah; Buhmeida, Abdelbaset; Khaled, Ben Romdhane; Abdalla, Fathi; Salem, Nada; Pyrhönen, Seppo; Collan, Yrjö

    2013-06-01

    We studied the association of the immunohistochemical bcl-2 expression in Libyan breast cancer with clinicopathological variables and patient outcome. Histological samples from 170 previously untreated primary Libyan breast carcinoma patients were examined. In immunohistochemistry, the NCL-L-bcl-2-486 monoclonal antibody was used. Positive expression of bcl-2 was found in 106 patients (62.4 %). The bcl-2 expression was significantly associated with estrogen receptor (p<0.0001) and progesterone receptor positive tumors (p=0.002), small tumor size (p<0.0001), low tumor grade (p<0.0001), negative axillary lymph nodes (p<0.0001), early stages (p=0.001), and low risk of metastasis (p<0.0001). Positive expression was also associated with older patients (>50 years; p=0.04). Histological subtypes and family history of breast cancer did not have significant relationship with bcl-2. Patients with positive expression of bcl-2 had lower recurrence rate than bcl-2-negative patients and better survival after median follow-up of 47 months. Patients with high bcl-2 staining were associated with the best survival. The role of bcl-2 as an independent predictor of disease-specific survival was assessed in a multivariate survival (Cox) analysis, including age, hormonal status, recurrence, histological grade, and clinical stage variables. Bcl-2 (p<0.0001) and clinical stage (p=0.016) were independent predicators of disease-specific survival. For analysis of disease-free survival, the same variables were entered to the model and only bcl-2 proved to be an independent predictor (p=0.002). Patients with positive expression of bcl-2 were associated with low grade of malignancy, with lower recurrence rate, with lower rate of death, and with longer survival time. Bcl-2 is an independent predictor of breast cancer outcome, and it provides useful prognostic information in Libyan breast cancer. Thus, it could be used with classical clinicopathological factors to improve patient selection for

  18. Expression of Bcl-2 in canine osteosarcoma

    PubMed Central

    Piro, F.; Leonardi, L.

    2015-01-01

    Osteosarcoma (OS) is the most common primary malignancy of bone. It is responsible for 80-85% of the primary bone tumors affecting dogs and it is characterized by aggressive and invasive behavior, with a high metastatic potential. Several studies on cancer and related tumorigenesis, show an involvement of the mechanisms of programmed cell death and cell survival. Many signals seem to be involved in the related mechanism of autophagy and in particular, our interest is focused on the expression of a family of Bcl-2 that seems to be involved either in the control of biomolecular mechanisms like autophagy and apoptosis. In this study we investigated the expression of Bcl-2 in different cases of spontaneous canine osteosarcoma and the related preliminary results are described. We found Bcl-2 activity was increased in OS tissue compared to normal bone tissue. These results suggested that Bcl-2 activity may play an important role in the formation of OS and as a diagnostic for neoplastic activity. However, further research is needed to confirm the role of Bcl-2 activity in OS in canines. PMID:26623359

  19. Involvement of PI3K and MAPK Signaling in bcl-2-induced Vascular Endothelial Growth Factor Expression in Melanoma Cells

    PubMed Central

    Trisciuoglio, Daniela; Iervolino, Angela; Zupi, Gabriella; Del Bufalo, Donatella

    2005-01-01

    We have previously demonstrated that bcl-2 overexpression in tumor cells exposed to hypoxia increases the expression of vascular endothelial growth factor (VEGF) gene through the hypoxia-inducible factor-1 (HIF-1). In this article, we demonstrate that exposure of bcl-2 overexpressing melanoma cells to hypoxia induced phosphorylation of AKT and extracellular signal-regulated kinase (ERK)1/2 proteins. On the contrary, no modulation of these pathways by bcl-2 was observed under normoxic conditions. When HIF-1α expression was reduced by RNA interference, AKT and ERK1/2 phosphorylation were still induced by bcl-2. Pharmacological inhibition of mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3-kinase (PI3K) signaling pathways reduced the induction of VEGF and HIF-1 in response to bcl-2 overexpression in hypoxia. No differences were observed between control and bcl-2-overexpressing cells in normoxia, in terms of VEGF protein secretion and in response to PI3K and MAPK inhibitors. We also demonstrated that RNA interference-mediated down-regulation of bcl-2 expression resulted in a decrease in the ERK1/2 phosphorylation and VEGF secretion only in bcl-2-overexpressing cell exposed to hypoxia but not in control cells. In conclusion, our results indicate, for the first time, that bcl-2 synergizes with hypoxia to promote expression of angiogenesis factors in melanoma cells through both PI3K- and MAPK-dependent pathways. PMID:15987743

  20. Is Bax/Bcl-2 Ratio Considered as a Prognostic Marker with Age and Tumor Location in Colorectal Cancer?

    PubMed Central

    Khodapasand, Ehsan; Jafarzadeh, Narges; Farrokhi, Farid; Kamalidehghan, Behnam; Houshmand, Massoud

    2015-01-01

    Background: Bax and Bcl-2 are the major members of Bcl-2 family whose play a key role in tumor progression or inhibition of intrinsic apoptotic pathway triggered by mitochondrial dysfunction. Therefore, the balance between pro- and anti-apoptotic members of this family can determine the cellular fate. Methods: In this study, the relative level of mRNA expression of Bax and Bcl-2 genes was determined using RNA extraction, cDNA synthesis and RT-qPCR technique from 22 tumoral tissues and adjacent non-tumoral tissues from adenocarcinoma colorectal cancer. Results: The potential prognostic and predictive significance of Bax and Bcl-2 gene expression and Bax/Bcl-2 ratio were demonstrated in colorectal cancer. The significant correlation between qPCR data and different clinicopathologic parameters of colorectal carcinoma, including age, gender, tumor size, tumor stage, tumor location, and tumor differentiation was also examined. Interestingly, no significant correlation was seen between Bax and Bcl-2 expressions and clinicopathological parameters of colorectal cancer. However, Bax/Bcl-2 ratio was statistically correlated with age and tumor location. Patients with age above 50 showed decreased levels of Bax/Bcl-2 ratio. Moreover, the Bax/Bcl-2 ratio was significantly lower in tumors resected from colon compared to sigmoid colon, rectosigmoid and rectum tumors. Conclusion: This study indicates a significant correlation between age and tumor location with Bax/Bcl-2 expression ratio, suggesting predictive value as a potential molecular marker of colorectal cancer. PMID:25864810

  1. Bcl-2△21 and Ac-DEVD-CHO Inhibit Death of Wheat Microspores

    PubMed Central

    Sinha, Rakesh K.; Pospíšil, Pavel; Maheshwari, Priti; Eudes, François

    2016-01-01

    Microspore cell death and low green plant production efficiency are an integral obstacle in the development of doubled haploid production in wheat. The aim of the current study was to determine the effect of anti-apoptotic recombinant human B-cell lymphoma-2 (Bcl-2△21) and caspase-3-inhibitor (Ac-DEVD-CHO) in microspore cell death in bread wheat cultivars AC Fielder and AC Andrew. Induction medium containing Bcl-2△21 and Ac-DEVD-CHO yielded a significantly higher number of viable microspores, embryo-like structures and total green plants in wheat cultivars AC Fielder and AC Andrew. Total peroxidase activity was lower in Bcl-2△21 treated microspore cultures at 96 h of treatment compared to control and Ac-DEVD-CHO. Electron paramagnetic resonance study of total microspore protein showed a different scavenging activity for Bcl-2△21 and Ac-DEVD-CHO. Bcl-2△21 scavenged approximately 50% hydroxyl radical (HO•) formed, whereas Ac-DEVD-CHO scavenged approximately 20% of HO•. Conversely, reduced caspase-3-like activities were detected in the presence of Bcl-2△21 and Ac-DEVD-CHO, supporting the involvement of Bcl-2△21 and Ac-DEVD-CHO in increasing microspore viability by reducing oxidative stress and caspase-3-like activity. Our results indicate that Bcl-2△21 and Ac-DEVD-CHO protects cells from cell death following different pathways. Bcl-2△21 prevents cell damage by detoxifying HO• and suppressing caspase-3-like activity, while Ac-DEVD-CHO inhibits the cell death pathways by modulating caspase-like activity. PMID:28082995

  2. Bcl-2△21 and Ac-DEVD-CHO Inhibit Death of Wheat Microspores.

    PubMed

    Sinha, Rakesh K; Pospíšil, Pavel; Maheshwari, Priti; Eudes, François

    2016-01-01

    Microspore cell death and low green plant production efficiency are an integral obstacle in the development of doubled haploid production in wheat. The aim of the current study was to determine the effect of anti-apoptotic recombinant human B-cell lymphoma-2 (Bcl-2△21) and caspase-3-inhibitor (Ac-DEVD-CHO) in microspore cell death in bread wheat cultivars AC Fielder and AC Andrew. Induction medium containing Bcl-2△21 and Ac-DEVD-CHO yielded a significantly higher number of viable microspores, embryo-like structures and total green plants in wheat cultivars AC Fielder and AC Andrew. Total peroxidase activity was lower in Bcl-2△21 treated microspore cultures at 96 h of treatment compared to control and Ac-DEVD-CHO. Electron paramagnetic resonance study of total microspore protein showed a different scavenging activity for Bcl-2△21 and Ac-DEVD-CHO. Bcl-2△21 scavenged approximately 50% hydroxyl radical (HO(•)) formed, whereas Ac-DEVD-CHO scavenged approximately 20% of HO(•). Conversely, reduced caspase-3-like activities were detected in the presence of Bcl-2△21 and Ac-DEVD-CHO, supporting the involvement of Bcl-2△21 and Ac-DEVD-CHO in increasing microspore viability by reducing oxidative stress and caspase-3-like activity. Our results indicate that Bcl-2△21 and Ac-DEVD-CHO protects cells from cell death following different pathways. Bcl-2△21 prevents cell damage by detoxifying HO(•) and suppressing caspase-3-like activity, while Ac-DEVD-CHO inhibits the cell death pathways by modulating caspase-like activity.

  3. Involvement of Bcl-2 and Bax in photodynamic therapy-mediated apoptosis. Antisense Bcl-2 oligonucleotide sensitizes RIF 1 cells to photodynamic therapy apoptosis.

    PubMed

    Srivastava, M; Ahmad, N; Gupta, S; Mukhtar, H

    2001-05-04

    Photodynamic therapy (PDT), a promising treatment modality, is an oxidative stress that induces apoptosis in many cancer cells in vitro and tumors in vivo. Understanding the mechanism(s) involved in PDT-mediated apoptosis may improve its therapeutic efficacy. Although studies suggest the involvement of multiple pathways, the triggering event(s) responsible for PDT-mediated apoptotic response is(are) not clear. To investigate the role of Bcl-2 in PDT-mediated apoptosis, we employed Bcl-2-antisense and -overexpression approaches in two cell types differing in their responses toward PDT apoptosis. In the first approach, we treated radiation-induced fibrosarcoma (RIF 1) cells, which are resistant to silicon phthalocyanine (Pc 4)-PDT apoptosis, with Bcl-2-antisense oligonucleotide. This treatment resulted in sensitization of RIF 1 cells to PDT-mediated apoptosis as demonstrated by i) cleavage of poly(ADP-ribose) polymerase, ii) DNA ladder formation, iii) terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL)-positive cells, and iv) DEVDase activity. This treatment also resulted in oligonucleotide concentration-dependent decrease in cell viability and down-regulation of Bcl-2 protein with a concomitant increase in apoptosis. However, the level of Bax, a pro-apoptotic member of Bcl-2 family, remained unaltered. In the second approach, an overexpression of Bcl-2 in PDT apoptosis-sensitive human epidermoid carcinoma (A431) cells resulted in enhanced apoptosis and up-regulation of Bax following PDT. In both the approaches, the increased Bax/Bcl-2 ratio was associated with an increased apoptotic response of PDT. Our data also demonstrated that PDT results in modulation of other Bcl-2 family members in a way that the overall ratio of pro-apoptotic and anti-apoptotic member proteins favors apoptosis.

  4. Locating herpesvirus Bcl-2 homologs in the specificity landscape of anti-apoptotic Bcl-2 proteins

    PubMed Central

    Foight, Glenna Wink; Keating, Amy E.

    2015-01-01

    Viral homologs of the anti-apoptotic Bcl-2 proteins are highly diverged from their mammalian counterparts, yet they perform overlapping functions by binding and inhibiting BH3 motif-containing proteins. We investigated the BH3 binding properties of the herpesvirus Bcl-2 homologs KSBcl-2, BHRF1, and M11, as they relate to those of the human Bcl-2 homologs Mcl-1, Bfl-1, Bcl-w, Bcl-xL, and Bcl-2. Analysis of the sequence and structure of the BH3 binding grooves showed that, despite low sequence identity, M11 has structural similarities to Bcl-xL, Bcl-2, and Bcl-w. BHRF1 and KSBcl-2 are more structurally similar to Mcl-1 than to the other human proteins. Binding to human BH3-like peptides showed that KSBcl-2 has similar specificity to Mcl-1, and BHRF1 has a restricted binding profile; M11 binding preferences are distinct from those of Bcl-xL, Bcl-2 and Bcl-w. Because KSBcl-2 and BHRF1 are from human herpesviruses associated with malignancies, we screened computationally designed BH3 peptide libraries using bacterial surface display to identify selective binders of KSBcl-2 or BHRF1. The resulting peptides bound to KSBcl-2 and BHRF1 in preference to Bfl-1, Bcl-w, Bcl-xL, and Bcl-2, but showed only modest specificity over Mcl-1. Rational mutagenesis increased specificity against Mcl-1, resulting in a peptide with a dissociation constant of 2.9 nM for binding to KSBcl-2 and >1000-fold specificity over human Bcl-2 proteins, and a peptide with >70-fold specificity for BHRF1. In addition to providing new insights into viral Bcl-2 binding specificity, this study will inform future work analyzing the interaction properties of homologous binding domains and designing specific protein interaction partners. PMID:26009469

  5. Diminishing Apoptosis by Deletion of Bax or Overexpression of Bcl-2 Does Not Protect against Infectious Prion Toxicity In Vivo

    PubMed Central

    Steele, Andrew D.; King, Oliver D.; Jackson, Walker S.; Hetz, Claudio A.; Borkowski, Andrew W.; Thielen, Peter; Wollmann, Robert; Lindquist, Susan

    2008-01-01

    B-cell lymphoma protein 2 (Bcl-2) and Bcl-2-associated X protein (Bax), key antiapoptotic and proapoptotic proteins, respectively, have important roles in acute and chronic models of neurologic disease. Several studies have implicated Bax and Bcl-2 in mediating neurotoxicity in prion diseases. To determine whether diminishing apoptotic cell death is protective in an infectious prion disease model we inoculated mice that either were null for proapoptotic Bax or overexpressed antiapoptotic Bcl-2. Interestingly, genetic manipulation of apoptosis did not lessen the clinical severity of disease. Moreover, some disease parameters, such as behavioral alterations and death, occurred slightly earlier in mice that are null for Bax or overexpress Bcl-2. These results suggest that Bax and Bcl-2 mediated apoptotic pathways are not the major contributing factor to the clinical or pathological features of infectious prion disease. PMID:18032675

  6. Clathrin-Independent Pathways of Endocytosis

    PubMed Central

    Mayor, Satyajit; Parton, Robert G.; Donaldson, Julie G.

    2014-01-01

    There are many pathways of endocytosis at the cell surface that apparently operate at the same time. With the advent of new molecular genetic and imaging tools, an understanding of the different ways by which a cell may endocytose cargo is increasing by leaps and bounds. In this review we explore pathways of endocytosis that occur in the absence of clathrin. These are referred to as clathrin-independent endocytosis (CIE). Here we primarily focus on those pathways that function at the small scale in which some have distinct coats (caveolae) and others function in the absence of specific coated intermediates. We follow the trafficking itineraries of the material endocytosed by these pathways and finally discuss the functional roles that these pathways play in cell and tissue physiology. It is likely that these pathways will play key roles in the regulation of plasma membrane area and tension and also control the availability of membrane during cell migration. PMID:24890511

  7. Bcl-2-family proteins and hematologic malignancies: history and future prospects.

    PubMed

    Reed, John C

    2008-04-01

    BCL-2 was the first antideath gene discovered, a milestone that effectively launched a new era in cell death research. Since its discovery more than 2 decades ago, multiple members of the human Bcl-2 family of apoptosis-regulating proteins have been identified, including 6 antiapoptotic proteins, 3 structurally similar proapoptotic proteins, and several structurally diverse proapoptotic interacting proteins that operate as upstream agonists or antagonists. Bcl-2-family proteins regulate all major types of cell death, including apoptosis, necrosis, and autophagy. As such, they operate as nodal points at the convergence of multiple pathways with broad relevance to biology and medicine. Bcl-2 derives its name from its original discovery in the context of B-cell lymphomas, where chromosomal translocations commonly activate the BCL-2 protooncogene, endowing B cells with a selective survival advantage that promotes their neoplastic expansion. The concept that defective programmed cell death contributes to malignancy was established by studies of Bcl-2, representing a major step forward in current understanding of tumorigenesis. Experimental therapies targeting Bcl-2 family mRNAs or proteins are currently in clinical testing, raising hopes that a new class of anticancer drugs may be near.

  8. Depletion of Bcl-2 by an antisense oligonucleotide induces apoptosis accompanied by oxidation and externalization of phosphatidylserine in NCI-H226 lung carcinoma cells.

    PubMed

    Koty, Patrick P; Tyurina, Yulia Y; Tyurin, Vladimir A; Li, Shang-Xi; Kagan, Valerian E

    2002-01-01

    Oxidant-induced apoptosis involves oxidation of many different and essential molecules including phospholipids. As a result of this non-specific oxidation, any signaling role of a particular phospholipid-class of molecules is difficult to elucidate. To determine whether preferential oxidation of phosphatidylserine (PS) is an early event in apoptotic signaling related to PS externalization and is independent of direct oxidant exposure, we chose a genetic-based induction of apoptosis. Apoptosis was induced in the lung cancer cell line NCI-H226 by decreasing the amount of Bcl-2 protein expression by preventing the translation of bcl-2 mRNA using an antisense bcl-2 oligonucleotide. Peroxidation of phospholipids was assayed using a fluorescent technique based on metabolic integration of an oxidation-sensitive and fluorescent fatty acid, cis-parinaric acid (PnA), into cellular phospholipids and subsequent HPLC separation of cis-PnA-labeled phospholipids. We found a decrease in Bcl-2 was associated with a selective oxidation of PS in a sub-population of the cells with externalized PS. No significant difference in oxidation of cis-PnA-labeled phospholipids was observed in cells treated with medium alone or a nonsense oligonucleotide. Treatment with either nonsensc or antisense bcl-2 oligonucleotides was not associated with changes in the pattern of individual phospholipid classes as determined by HPTLC. These metabolic and topographical changes in PS arrangement in plasma membrane appear to be early responses to antisense bcl-2 exposure that trigger a PS-dependent apoptotic signaling pathway. This observed externalization of PS may facilitate the 'labeling' of apoptotic cells for recognition by macrophage scavenger receptors and subsequent phagocytic clearance.

  9. BCL-2 and BCL-XL restrict lineage choice during hematopoietic differentiation.

    PubMed

    Haughn, Loralee; Hawley, Robert G; Morrison, Deborah K; von Boehmer, Harald; Hockenbery, David M

    2003-07-04

    Differentiation of hematopoietic cells from multipotential progenitors is regulated by multiple growth factors and cytokines. A prominent feature of these soluble factors is promotion of cell survival, in part mediated by expression of either of the anti-apoptotic proteins, BCL-2 and BCL-XL. The complex expression pattern of these frequently redundant survival factors during hematopoiesis may indicate a role in lineage determination. To investigate the latter possibility, we analyzed factor-dependent cell-Patersen (FDCP)-Mix multipotent progenitor cells in which we stably expressed BCL-2 or BCL-XL. Each factor maintained complete survival of interleukin-3 (IL-3)-deprived FDCP-Mix cells but, unexpectedly, directed FDCP-Mix cells along restricted and divergent differentiation pathways. Thus, IL-3-deprived FDCP-Mix BCL-2 cells differentiated exclusively to granulocytes and monocytes/macrophages, whereas FDCP-Mix BCL-XL cells became erythroid. FDCP-Mix BCL-2 cells grown in IL-3 were distinguished from FDCP-Mix and FDCP-Mix BCL-XL cells by a striking reduction in cellular levels of Raf-1 protein. Replacement of the BCL-2 BH4 domain with the related BCL-XL BH4 sequence resulted in a switch of FDCP-Mix BCL-2 cells to erythroid fate accompanied by persistence of Raf-1 protein expression. Moreover, enforced expression of Raf-1 redirected FDCP-Mix BCL-2 cells to an erythroid fate, and prohibited generation of myeloid cells. These results identify novel roles for BCL-2 and BCL-XL in cell fate decisions beyond cell survival. These effects are associated with differential regulation of Raf-1 expression, perhaps involving the previously identified interaction between BCL-2-BH4 and the catalytic domain of Raf-1.

  10. Expression of Bcl-2 and Bcl-2-Ig fusion transcripts in normal and neoplastic cells.

    PubMed Central

    Graninger, W B; Seto, M; Boutain, B; Goldman, P; Korsmeyer, S J

    1987-01-01

    We examined the expression of the Bcl-2 gene at chromosome segment 18q21, that is translocated into the Ig heavy chain gene locus in t(14;18) bearing lymphomas. Bcl-2, while B cell associated, is expressed in a variety of hematopoietic lineages including T cells. Bcl-2 mRNA levels are high during pre-B cell development, the time at which the t(14;18) translocation occurs, but are down regulated with maturation. Like certain other oncogenes, Bcl-2 is quiescent in resting B cells but up-regulated with B cell activation. Mature B cell lymphomas with a t(14;18) have log-folds more mRNA than matched counterparts without the translocation. A sensitive S1 protection assay revealed that all transcripts in t(14;18) B cells were Bcl-2-Ig fusion mRNAs and originated from the translocated allele. Thus, there is a marked deregulation of Bcl-2 when it is introduced into the Ig locus in t(14;18) lymphomas. Images PMID:3500184

  11. Cross talk between cell death and cell cycle progression: BCL-2 regulates NFAT-mediated activation.

    PubMed Central

    Linette, G P; Li, Y; Roth, K; Korsmeyer, S J

    1996-01-01

    BCL-2-deficient T cells demonstrate accelerated cell cycle progression and increased apoptosis following activation. Increasing the levels of BCL-2 retarded the G0-->S transition, sustained the levels of cyclin-dependent kinase inhibitor p27Kip1, and repressed postactivation death. Proximal signal transduction events and immediate early gene transcription were unaffected. However, the transcription and synthesis of interleukin 2 and other delayed early cytokines were markedly attenuated by BCL-2. In contrast, a cysteine protease inhibitor that also blocks apoptosis had no substantial affect upon cytokine production. InterleUkin 2 expression requires several transcription factors of which nuclear translocation of NFAT (nuclear factor of activated T cells) and NFAT-mediated transactivation were impaired by BCL-2. Thus, select genetic aberrations in the apoptotic pathway reveal a cell autonomous coregulation of activation. Images Fig. 3 Fig. 4 Fig. 7 PMID:8790367

  12. FBXO10 deficiency and BTK activation upregulate BCL2 expression in mantle cell lymphoma

    PubMed Central

    Li, Y; Bouchlaka, MN; Wolff, J; Grindle, KM; Lu, L; Qian, S; Zhong, X; Pflum, N; Jobin, P; Kahl, BS; Eickhoff, JC; Wuerzberger-Davis, SM; Miyamoto, S; Thomas, CJ; Yang, DT; Capitini, CM; Rui, L

    2016-01-01

    Targeting Bruton tyrosine kinase (BTK) by ibrutinib is an effective treatment for patients with relapsed/refractory mantle cell lymphoma (MCL). However, both primary and acquired resistance to ibrutinib have developed in a significant number of these patients. A combinatory strategy targeting multiple oncogenic pathways is critical to enhance the efficacy of ibrutinib. Here, we focus on the BCL2 anti-apoptotic pathway. In a tissue microarray of 62 MCL samples, BCL2 expression positively correlated with BTK expression. Increased levels of BCL2 were shown to be due to a defect in protein degradation because of no or little expression of the E3 ubiquitin ligase FBXO10, as well as transcriptional upregulation through BTK-mediated canonical nuclear factor-κB activation. RNA-seq analysis confirmed that a set of anti-apoptotic genes (for example, BCL2, BCL-XL and DAD1) was downregulated by BTK short hairpin RNA. The downregulated genes also included those that are critical for B-cell growth and proliferation, such as BCL6, MYC, PIK3CA and BAFF-R. Targeting BCL2 by the specific inhibitor ABT-199 synergized with ibrutinib in inhibiting growth of both ibrutinib-sensitive and -resistant cancer cells in vitro and in vivo. These results suggest co-targeting of BTK and BCL2 as a new therapeutic strategy in MCL, especially for patients with primary resistance to ibrutinib. PMID:27157620

  13. The Anti-apoptotic Protein BCL2L1/Bcl-xL Is Neutralized by Pro-apoptotic PMAIP1/Noxa in Neuroblastoma, Thereby Determining Bortezomib Sensitivity Independent of Prosurvival MCL1 Expression*

    PubMed Central

    Hagenbuchner, Judith; Ausserlechner, Michael J.; Porto, Verena; David, Reinhard; Meister, Bernhard; Bodner, Martin; Villunger, Andreas; Geiger, Kathrin; Obexer, Petra

    2010-01-01

    Neuroblastoma is the most frequent extracranial solid tumor in children. Here, we report that the proteasome inhibitor bortezomib (PS-341, Velcade) activated the pro-apoptotic BH3-only proteins PMAIP1/Noxa and BBC3/Puma and induced accumulation of anti-apoptotic MCL1 as well as repression of anti-apoptotic BCL2L1/Bcl-xL. Retroviral expression of Bcl-xL, but not of MCL1, prevented apoptosis by bortezomib. Gene knockdown of Noxa by shRNA technology significantly reduced apoptosis, whereas Puma knockdown did not affect cell death kinetics. Immunoprecipitation revealed that endogenous Noxa associated with both, Bcl-xL and MCL1, suggesting that in neuronal cells Noxa can neutralize Bcl-xL, explaining the pronounced protective effect of Bcl-xL. Tetracycline-regulated Noxa expression did not trigger cell death per se but sensitized to bortezomib treatment in a dose-dependent manner. This implies that the induction of Noxa is necessary but not sufficient for bortezomib-induced apoptosis. We conclude that MCL1 steady-state expression levels do not affect sensitivity to proteasome-inhibitor treatment in neuronal tumor cells, and that both the repression of Bcl-xL and the activation of Noxa are necessary for bortezomib-induced cell death. PMID:20051518

  14. Bcl2 is a critical regulator of bile acid homeostasis by dictating Shp and lncRNA H19 function

    PubMed Central

    Zhang, Yuxia; Liu, Chune; Barbier, Olivier; Smalling, Rana; Tsuchiya, Hiroyuki; Lee, Sangmin; Delker, Don; Zou, An; Hagedorn, Curt H.; Wang, Li

    2016-01-01

    Bile acid (BA) metabolism is tightly controlled by nuclear receptor signaling to coordinate regulation of BA synthetic enzymes and transporters. Here we reveal a molecular cascade consisting of the antiapoptotic protein BCL2, nuclear receptor Shp, and long non-coding RNA (lncRNA) H19 to maintain BA homeostasis. Bcl2 was overexpressed in liver of C57BL/6J mice using adenovirus mediated gene delivery for two weeks. Hepatic overexpression of Bcl2 caused drastic accumulation of serum BA and bilirubin levels and dysregulated BA synthetic enzymes and transporters. Bcl2 reactivation triggered severe liver injury, fibrosis and inflammation, which were accompanied by a significant induction of H19. Bcl2 induced rapid SHP protein degradation via the activation of caspase-8 pathway. The induction of H19 in Bcl2 overexpressed mice was contributed by a direct loss of Shp transcriptional repression. H19 knockdown or Shp re-expression largely rescued Bcl2-induced liver injury. Strikingly different than Shp, the expression of Bcl2 and H19 was hardly detectable in adult liver but was markedly increased in fibrotic/cirrhotic human and mouse liver. We demonstrated for the first time a detrimental effect of Bcl2 and H19 associated with cholestatic liver fibrosis and an indispensable role of Shp to maintain normal liver function. PMID:26838806

  15. Diosmetin triggers cell apoptosis by activation of the p53/Bcl-2 pathway and inactivation of the Notch3/NF-κB pathway in HepG2 cells

    PubMed Central

    Qiao, Jie; Liu, Jie; Jia, Kaiqiao; Li, Ning; Liu, Bin; Zhang, Qingyu; Zhu, Runzhi

    2016-01-01

    Diosmetin (DIOS), a flavonoid compound, is abundant in Citrus limon. Emerging studies have shown that DIOS is an effective compound implicated in multiple types of cancer. However, whether DIOS serves a role in hepatocellular carcinoma (HCC) is still obscure. HepG2 cells were used in the present study, and it was observed that DIOS exhibited antitumor activity against liver cancer cells. Western blotting was performed to evaluate cell apoptosis and survival-associated proteins, and the results demonstrated that DIOS treatment resulted in the activation of the p53-dependent apoptosis pathway. Our results revealed that DIOS caused inhibition of the nuclear factor (NF)-κB signaling pathway and downregulation of Notch3 receptor. Furthermore, by using small hairpin RNA-Notch3, it was confirmed that DIOS inhibited the NF-κB signaling pathway by inactivation of Notch3. In conclusion, the present results demonstrated that DIOS triggered cell apoptosis by activation of the p53 signaling pathway and inhibited the NF-κB cell survival pathway by downregulation of Notch3 receptor expression. DIOS is a potential agent for prevention of HCC. PMID:28101238

  16. Algae: America’s Pathway to Independence

    DTIC Science & Technology

    2007-03-30

    Bioenergy, Biofuel, Energy Policy CLASSIFICATION: Unclassified The United States is dependent on foreign oil to meet 63% of its petroleum demand...source of bioenergy. ALGAE: AMERICA’S PATHWAY TO INDEPENDENCE Ensuring a secure supply of energy is a strategic challenge for...150 years,6 the U.S. will be competing with other nations to procure the 2 finite commodity. The Department of Energy (DOE) estimates that by the

  17. Bcl-2high mantle cell lymphoma cells are sensitized to acadesine with ABT-199

    PubMed Central

    Montraveta, Arnau; Xargay-Torrent, Sílvia; Rosich, Laia; López-Guerra, Mònica; Roldán, Jocabed; Rodríguez, Vanina; Lee-Vergés, Eriong; de Frías, Mercè; Campàs, Clara; Campo, Elias; Roué, Gaël; Colomer, Dolors

    2015-01-01

    Acadesine is a nucleoside analogue with known activity against B-cell malignancies. Herein, we showed that in mantle cell lymphoma (MCL) cells acadesine induced caspase-dependent apoptosis through turning on the mitochondrial apoptotic machinery. At the molecular level, the compound triggered the activation of the AMPK pathway, consequently modulating known downstream targets, such as mTOR and the cell motility-related vasodilator-stimulated phosphoprotein (VASP). VASP phosphorylation by acadesine was concomitant with a blockade of CXCL12-induced migration. The inhibition of the mTOR cascade by acadesine, committed MCL cells to enter in apoptosis by a translational downregulation of the antiapoptotic Mcl-1 protein. In contrast, Bcl-2 protein levels were unaffected by acadesine and MCL samples expressing high levels of Bcl-2 tended to have a reduced response to the drug. Targeting Bcl-2 with the selective BH3-mimetic agent ABT-199 sensitized Bcl-2 high MCL cells to acadesine. This effect was validated in vivo, where the combination of both agents displayed a more marked inhibition of tumor outgrowth than each drug alone. These findings support the notions that antiapoptotic proteins of the Bcl-2 family regulate MCL cell sensitivity to acadesine and that the combination of this agent with Bcl-2 inhibitors might be an interesting therapeutic option to treat MCL patients. PMID:26110568

  18. Quantification of protein copy number in single mitochondria: The Bcl-2 family proteins.

    PubMed

    Chen, Chaoxiang; Zhang, Xiang; Zhang, Shuyue; Zhu, Shaobin; Xu, Jingyi; Zheng, Yan; Han, Jinyan; Zeng, Jin-Zhang; Yan, Xiaomei

    2015-12-15

    Bcl-2 family proteins, represented by antiapoptotic protein Bcl-2 and proapoptotic protein Bax, are key regulators of mitochondria-mediated apoptosis pathway. To build a quantitative model of how Bcl-2 family protein interactions control mitochondrial outer membrane permeabilization and subsequent cytochrome c release, it is essential to know the number of proteins in individual mitochondria. Here, we report an effective method to quantify the copy number and distribution of proteins in single mitochondria via immunofluorescent labeling and sensitive detection by a laboratory-built high sensitivity flow cytometer (HSFCM). Mitochondria isolated from HeLa cells were stained with Alexa Fluor 488 (AF488)-labeled monoclonal antibodies specifically targeting Bcl-2 or Bax and with nucleic acid dye. A series of fluorescent nanospheres with fluorescence intensity calibrated in the unit of molecules of equivalent soluble fluorochrome (MESF)-AF488 were used to construct a calibration curve for converting the immunofluorescence of a single mitochondrion to the number of antibodies bound to it and then to the number of proteins per mitochondrion. Under the normal condition, the measured mean copy numbers were 1300 and 220 per mitochondrion for Bcl-2 and Bax, respectively. A significant variation in protein copy number was identified, which ranged from 130 to 6000 (2.5-97.5%) for Bcl-2 and from 65 to 700 (2.5-97.5%) for Bax, respectively. We observed an approximately 4.4 fold increase of Bax copy number per mitochondrion upon 9h of apoptosis stimulation while the abundance of Bcl-2 remained almost unchanged. To the best of our knowledge, this is the first report of Bcl-2 family protein copy number and variance in single mitochondria. Collectively, we demonstrate that the HSFCM-based immunoassay provides a rapid and sensitive method for determining protein copy number distribution in single mitochondria.

  19. Predictive Bcl-2 Family Binding Models Rooted in Experiment or Structure

    PubMed Central

    DeBartolo, Joe; Dutta, Sanjib; Reich, Lothar; Keating, Amy E.

    2013-01-01

    Proteins of the Bcl-2 family either enhance or suppress programmed cell death and are centrally involved in cancer development and resistance to chemotherapy. BH3 (Bcl-2 homology 3)-only Bcl-2 proteins promote cell death by docking an α-helix into a hydrophobic groove on the surface of one or more of five pro-survival Bcl-2 receptor proteins. There is high structural homology within the pro-death and pro-survival families, yet a high degree of interaction specificity is nevertheless encoded, posing an interesting and important molecular recognition problem. Understanding protein features that dictate Bcl-2 interaction specificity is critical for designing peptide-based cancer therapeutics and diagnostics. In this study, we present peptide SPOT arrays and deep sequencing data from yeast display screening experiments that significantly expand the BH3 sequence space that has been experimentally tested for interaction with five human anti-apoptotic receptors. These data provide rich information about the determinants of Bcl-2 family specificity. To interpret and use the information, we constructed two simple data-based models that can predict affinity and specificity when evaluated on independent data sets within a limited sequence space. We also constructed a novel structure-based statistical potential, called STATIUM, which is remarkably good at predicting Bcl-2 affinity and specificity, especially considering it is not trained on experimental data. We compare the performance of our three models to each other and to alternative structure-based methods and discuss how such tools can guide prediction and design of new Bcl-2 family complexes. PMID:22617328

  20. A component of green tea (-)-epigallocatechin-3-gallate, promotes apoptosis in T24 human bladder cancer cells via modulation of the PI3K/Akt pathway and Bcl-2 family proteins

    SciTech Connect

    Qin Jie; Xie Liping . E-mail: xielp@zjuem.zju.edu.cn; Zheng Xiangyi; Wang Yunbin; Bai Yu; Shen Huafeng; Li Longcheng; Dahiya, Rajvir

    2007-03-23

    Bladder cancer is the fourth most common cancer in men and ninth most common in women. It has a protracted course of progression and is thus an ideal candidate for chemoprevention strategies and trials. This study was conducted to evaluate the chemopreventive/antiproliferative potential of (-)-epigallocatechin gallate (EGCG, the major phytochemical in green tea) against bladder cancer and its mechanism of action. Using the T24 human bladder cancer cell line, we found that EGCG treatment caused dose- and time-dependent inhibition of cellular proliferation and cell viability, and induced apoptosis. Mechanistically, EGCG inhibits phosphatidylinositol 3'-kinase/Akt activation that, in turn, results in modulation of Bcl-2 family proteins, leading to enhanced apoptosis of T24 cells. These findings suggest that EGCG may be an important chemoprevention agent for the management of bladder cancer.

  1. BCL-2 is dispensable for thrombopoiesis and platelet survival

    PubMed Central

    Debrincat, M A; Pleines, I; Lebois, M; Lane, R M; Holmes, M L; Corbin, J; Vandenberg, C J; Alexander, W S; Ng, A P; Strasser, A; Bouillet, P; Sola-Visner, M; Kile, B T; Josefsson, E C

    2015-01-01

    Navitoclax (ABT-263), an inhibitor of the pro-survival BCL-2 family proteins BCL-2, BCL-XL and BCL-W, has shown clinical efficacy in certain BCL-2-dependent haematological cancers, but causes dose-limiting thrombocytopaenia. The latter effect is caused by Navitoclax directly inducing the apoptotic death of platelets, which are dependent on BCL-XL for survival. Recently, ABT-199, a selective BCL-2 antagonist, was developed. It has shown promising anti-leukaemia activity in patients whilst sparing platelets, suggesting that the megakaryocyte lineage does not require BCL-2. In order to elucidate the role of BCL-2 in megakaryocyte and platelet survival, we generated mice with a lineage-specific deletion of Bcl2, alone or in combination with loss of Mcl1 or Bclx. Platelet production and platelet survival were analysed. Additionally, we made use of BH3 mimetics that selectively inhibit BCL-2 or BCL-XL. We show that the deletion of BCL-2, on its own or in concert with MCL-1, does not affect platelet production or platelet lifespan. Thrombocytopaenia in Bclx-deficient mice was not affected by additional genetic loss or pharmacological inhibition of BCL-2. Thus, BCL-2 is dispensable for thrombopoiesis and platelet survival in mice. PMID:25880088

  2. BCL-2 is dispensable for thrombopoiesis and platelet survival.

    PubMed

    Debrincat, M A; Pleines, I; Lebois, M; Lane, R M; Holmes, M L; Corbin, J; Vandenberg, C J; Alexander, W S; Ng, A P; Strasser, A; Bouillet, P; Sola-Visner, M; Kile, B T; Josefsson, E C

    2015-04-16

    Navitoclax (ABT-263), an inhibitor of the pro-survival BCL-2 family proteins BCL-2, BCL-XL and BCL-W, has shown clinical efficacy in certain BCL-2-dependent haematological cancers, but causes dose-limiting thrombocytopaenia. The latter effect is caused by Navitoclax directly inducing the apoptotic death of platelets, which are dependent on BCL-XL for survival. Recently, ABT-199, a selective BCL-2 antagonist, was developed. It has shown promising anti-leukaemia activity in patients whilst sparing platelets, suggesting that the megakaryocyte lineage does not require BCL-2. In order to elucidate the role of BCL-2 in megakaryocyte and platelet survival, we generated mice with a lineage-specific deletion of Bcl2, alone or in combination with loss of Mcl1 or Bclx. Platelet production and platelet survival were analysed. Additionally, we made use of BH3 mimetics that selectively inhibit BCL-2 or BCL-XL. We show that the deletion of BCL-2, on its own or in concert with MCL-1, does not affect platelet production or platelet lifespan. Thrombocytopaenia in Bclx-deficient mice was not affected by additional genetic loss or pharmacological inhibition of BCL-2. Thus, BCL-2 is dispensable for thrombopoiesis and platelet survival in mice.

  3. MicroRNA-181c targets Bcl-2 and regulates mitochondrial morphology in myocardial cells

    PubMed Central

    Wang, Hongjiang; Li, Jing; Chi, Hongjie; Zhang, Fan; Zhu, Xiaoming; Cai, Jun; Yang, Xinchun

    2015-01-01

    Apoptosis is an important mechanism for the development of heart failure. Mitochondria are central to the execution of apoptosis in the intrinsic pathway. The main regulator of mitochondrial pathway of apoptosis is Bcl-2 family which includes pro- and anti-apoptotic proteins. MicroRNAs are small noncoding RNA molecules that regulate gene expression by inhibiting mRNA translation and/or inducing mRNA degradation. It has been proposed that microRNAs play critical roles in the cardiovascular physiology and pathogenesis of cardiovascular diseases. Our previous study has found that microRNA-181c, a miRNA expressed in the myocardial cells, plays an important role in the development of heart failure. With bioinformatics analysis, we predicted that miR-181c could target the 3′ untranslated region of Bcl-2, one of the anti-apoptotic members of the Bcl-2 family. Thus, we have suggested that miR-181c was involved in regulation of Bcl-2. In this study, we investigated this hypothesis using the Dual-Luciferase Reporter Assay System. Cultured myocardial cells were transfected with the mimic or inhibitor of miR-181c. We found that the level of miR-181c was inversely correlated with the Bcl-2 protein level and that transfection of myocardial cells with the mimic or inhibitor of miR-181c resulted in significant changes in the levels of caspases, Bcl-2 and cytochrome C in these cells. The increased level of Bcl-2 caused by the decrease in miR-181c protected mitochondrial morphology from the tumour necrosis factor alpha-induced apoptosis. PMID:25898913

  4. 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyride neurotoxicity is attenuated in mice overexpressing Bcl-2.

    PubMed

    Yang, L; Matthews, R T; Schulz, J B; Klockgether, T; Liao, A W; Martinou, J C; Penney, J B; Hyman, B T; Beal, M F

    1998-10-15

    The proto-oncogene Bcl-2 rescues cells from a wide variety of insults. Recent evidence suggests that Bcl-2 protects against free radicals and that it increases mitochondrial calcium-buffering capacity. The neurotoxicity of 1-methyl-4-phenyl-1,2,3, 6-tetrahydropyride (MPTP) is thought to involve both mitochondrial dysfunction and free radical generation. We therefore investigated MPTP neurotoxicity in both Bcl-2 overexpressing mice and littermate controls. MPTP-induced depletion of dopamine and loss of [3H]mazindol binding were significantly attenuated in Bcl-2 overexpressing mice. Protection was more profound with an acute dosing regimen than with daily MPTP administration over 5 d. 1-Methyl-4-phenylpyridinium (MPP+) levels after MPTP administration were similar in Bcl-2 overexpressing mice and littermates. Bcl-2 blocked MPP+-induced activation of caspases. MPTP-induced increases in free 3-nitrotyrosine levels were blocked in Bcl-2 overexpressing mice. These results indicate that Bcl-2 overexpression protects against MPTP neurotoxicity by mechanisms that may involve both antioxidant activity and inhibition of apoptotic pathways.

  5. Molecular Basis for Bcl-2 Homology 3 Domain Recognition in the Bcl-2 Protein Family

    PubMed Central

    Moroy, Gautier; Martin, Elyette; Dejaegere, Annick; Stote, Roland H.

    2009-01-01

    The proteins of the Bcl-2 family are important regulators of apoptosis, or programmed cell death. These proteins regulate this fundamental biological process via the formation of heterodimers involving both pro- and anti-apoptotic family members. Disruption of the balance between anti- and pro-apoptotic Bcl-2 proteins is the cause of numerous pathologies. Bcl-xl, an anti-apoptotic protein of this family, is known to form heterodimers with multiple pro-apoptotic proteins, such as Bad, Bim, Bak, and Bid. To elucidate the molecular basis of this recognition process, we used molecular dynamics simulations coupled with the Molecular Mechanics/Poisson-Boltzmann Surface Area approach to identify the amino acids that make significant energetic contributions to the binding free energy of four complexes formed between Bcl-xl and pro-apoptotic Bcl-2 homology 3 peptides. A fifth protein-peptide complex composed of another anti-apoptotic protein, Bcl-w, in complex with the peptide from Bim was also studied. The results identified amino acids of both the anti-apoptotic proteins as well as the Bcl-2 homology 3 (BH3) domains of the pro-apoptotic proteins that make strong, recurrent interactions in the protein complexes. The calculations show that the two anti-apoptotic proteins, Bcl-xl and Bcl-w, share a similar recognition mechanism. Our results provide insight into the molecular basis for the promiscuous nature of this molecular recognition process by members of the Bcl-2 protein family. These amino acids could be targeted in the design of new mimetics that serve as scaffolds for new antitumoral molecules. PMID:19293158

  6. Persea declinata (Bl.) Kosterm Bark Crude Extract Induces Apoptosis in MCF-7 Cells via G0/G1 Cell Cycle Arrest, Bcl-2/Bax/Bcl-xl Signaling Pathways, and ROS Generation.

    PubMed

    Narrima, Putri; Paydar, Mohammadjavad; Looi, Chung Yeng; Wong, Yi Li; Taha, Hairin; Wong, Won Fen; Ali Mohd, Mustafa; Hadi, A Hamid A

    2014-01-01

    Persea declinata (Bl.) Kosterm is a member of the Lauraceae family, widely distributed in Southeast Asia. It is from the same genus with avocado (Persea americana Mill), which is widely consumed as food and for medicinal purposes. In the present study, we examined the anticancer properties of Persea declinata (Bl.) Kosterm bark methanolic crude extract (PDM). PDM exhibited a potent antiproliferative effect in MCF-7 human breast cancer cells, with an IC50 value of 16.68 µg/mL after 48 h of treatment. We observed that PDM caused cell cycle arrest and subsequent apoptosis in MCF-7 cells, as exhibited by increased population at G0/G1 phase, higher lactate dehydrogenase (LDH) release, and DNA fragmentation. Mechanistic studies showed that PDM caused significant elevation in ROS production, leading to perturbation of mitochondrial membrane potential, cell permeability, and activation of caspases-3/7. On the other hand, real-time PCR and Western blot analysis showed that PDM treatment increased the expression of the proapoptotic molecule, Bax, but decreased the expression of prosurvival proteins, Bcl-2 and Bcl-xL, in a dose-dependent manner. These findings imply that PDM could inhibit proliferation in MCF-7 cells via cell cycle arrest and apoptosis induction, indicating its potential as a therapeutic agent worthy of further development.

  7. BCL2L12 Is a Novel Biomarker for the Prediction of Short-Term Relapse in Nasopharyngeal Carcinoma

    PubMed Central

    Fendri, Ali; Kontos, Christos K; Khabir, Abdelmajid; Mokdad-Gargouri, Raja; Scorilas, Andreas

    2011-01-01

    BCL2-like 12 (BCL2L12 ) is a new member of the apoptosis-related BCL2 gene family, members of which are implicated in various malignancies. Nasopharyngeal carcinoma is a highly metastatic, malignant epithelial tumor, with a high prevalence in Southeast Asia and North Africa. The purpose of the current study was to quantify and investigate the expression levels of the BCL2L12 gene in nasopharyngeal carcinoma biopsies and to assess its prognostic value. Total RNA was isolated from 89 malignant and hyperplastic nasopharyngeal biopsies from Tunisian patients. After testing the quality of the extracted RNA, cDNA was prepared by reverse transcription. A highly sensitive real-time polymerase chain reaction (PCR) method for BCL2L12 mRNA quantification was developed using SYBR® Green chemistry. GAPDH served as a reference gene. Relative quantification analysis was performed using the comparative CT (2−ΔΔCT) method. Higher BCL2L12 mRNA levels were detected in undifferentiated carcinomas of the nasopharynx, rather than in nonkeratinizing nasopharyngeal tumors (P = 0.045). BCL2L12 expression status was also found to be positively associated with the presence of distant metastases (P = 0.014). Kaplan-Meier survival analysis demonstrated that patients with BCL2L12-positive nasopharyngeal tumors have significantly shorter disease-free survival (P = 0.020). Cox regression analysis showed BCL2L12 expression to be an unfavorable and independent prognostic indicator of short-term relapse in nasopharyngeal carcinoma (P = 0.042). Our results suggest that mRNA expression of BCL2L12 may constitute a novel biomarker for the prediction of short-term relapse in nasopharyngeal carcinoma. PMID:21152697

  8. The Bcl-2 family: roles in cell survival and oncogenesis.

    PubMed

    Cory, Suzanne; Huang, David C S; Adams, Jerry M

    2003-11-24

    Apoptosis, the cell-suicide programme executed by caspases, is critical for maintaining tissue homeostasis, and impaired apoptosis is now recognized to be a key step in tumorigenesis. Whether a cell should live or die is largely determined by the Bcl-2 family of anti- and proapoptotic regulators. These proteins respond to cues from various forms of intracellular stress, such as DNA damage or cytokine deprivation, and interact with opposing family members to determine whether or not the caspase proteolytic cascade should be unleashed. This review summarizes current views of how these proteins sense stress, interact with their relatives, perturb organelles such as the mitochondrion and endoplasmic reticulum and govern pathways to caspase activation. It briefly explores how family members influence cell-cycle entry and outlines the evidence for their involvement in tumour development, both as oncoproteins and tumour suppressors. Finally, it discusses the promise of novel anticancer therapeutics that target these vital regulators.

  9. Protect and serve: Bcl-2 proteins as guardians and rulers of cancer cell survival

    PubMed Central

    Braun, Frédérique; de Carné Trécesson, Sophie; Bertin-Ciftci, Joséphine; Juin, Philippe

    2013-01-01

    It is widely accepted that anti-apoptotic Bcl-2 family members promote cancer cell survival by binding to their pro-apoptotic counterparts, thereby preventing mitochondrial outer membrane permeabilization (MOMP) and cytotoxic caspase activation. Yet, these proteins do not only function as guardians of mitochondrial permeability, preserving it, and maintaining cell survival in the face of acute or chronic stress, they also regulate non-apoptotic functions of caspases and biological processes beyond MOMP from diverse subcellular localizations and in complex with numerous binding partners outside of the Bcl-2 family. In particular, some of the non-canonical effects and functions of Bcl-2 homologs lead to an interplay with E2F-1, NFκB, and Myc transcriptional pathways, which themselves influence cancer cell growth and survival. We thus propose that, by feedback loops that we currently have only hints of, Bcl-2 proteins may act as rulers of survival signaling, predetermining the apoptotic threshold that they also directly scaffold. This underscores the robustness of the control exerted by Bcl-2 homologs over cancer cell survival, and implies that small molecules compounds currently used in the clinic to inhibit their mitochondrial activity may be not always be fully efficient to override this control. PMID:23974114

  10. Bcl-2 family proteins in breast development and cancer: could Mcl-1 targeting overcome therapeutic resistance?

    PubMed Central

    Williams, Michelle M.; Cook, Rebecca S.

    2015-01-01

    Apoptosis, cell death executed by caspases, is essential to normal breast development and homeostasis. Pro-apoptotic and anti-apoptotic signals are tightly regulated in normal breast epithelial cells. Dysregulation of this balance is required for breast tumorigenesis and increases acquired resistance to treatments, including molecularly targeted therapies, radiation and chemotherapies. The pro-apoptotic or anti-apoptotic Bcl-2 family members interact with each other to maintain mitochondrial integrity and regulate cellular commitment to apoptosis. Among the anti-apoptotic Bcl-2 family members, Mcl-1 is uniquely regulated by numerous oncogenic signaling pathways. This review will focus on the role of Bcl-2 family proteins in normal breast development, breast tumorigenesis and acquired resistance to breast cancer treatment strategies, while highlighting Mcl-1 as a promising target to improve breast cancer tumor cell killing. PMID:25784482

  11. Phage display screen for peptides that bind Bcl-2 protein.

    PubMed

    Park, Hye-Yeon; Kim, Joungmok; Cho, June-Haeng; Moon, Ji Young; Lee, Su-Jae; Yoon, Moon-Young

    2011-01-01

    Bcl-2 family proteins are key regulators of apoptosis associated with human disease, including cancer. Bcl-2 protein has been found to be overexpressed in many cancer cells. Therefore, Bcl-2 protein is a potential diagnostic target for cancer detection. In the present study, the authors have identified several Bcl-2 binding peptides with high affinity (picomolar range) from a 5-round M13 phage display library screening. These peptides can be used to develop novel diagnostic probes or potent inhibitors with diverse polyvalencies.

  12. Regulation of mitochondrial nutrient and energy metabolism by BCL-2 family proteins

    PubMed Central

    Giménez-Cassina, Alfredo; Danial, Nika N.

    2015-01-01

    Cells have evolved a highly integrated network of mechanisms to coordinate cellular survival/death, proliferation, differentiation, and repair with metabolic states. It is, therefore, not surprising that proteins with canonical roles in cell death/survival also modulate nutrient and energy metabolism and vice versa. The finding that many BCL-2 (B cell lymphoma 2) proteins reside at mitochondria or can translocate to this organelle has long motivated investigation into their involvement in normal mitochondrial physiology and metabolism. These endeavors have led to the discovery of homeostatic roles for BCL-2 proteins beyond apoptosis. Here, we predominantly focus on recent findings that link select BCL-2 proteins to carbon substrate utilization at the level of mitochondrial fuel choice, electron transport, and metabolite import independent of their cell death regulatory function. PMID:25748272

  13. BCL-2 family member BOK promotes apoptosis in response to endoplasmic reticulum stress

    PubMed Central

    Carpio, Marcos A.; Michaud, Michael; Zhou, Wenping; Fisher, Jill K.; Walensky, Loren D.; Katz, Samuel G.

    2015-01-01

    B-cell lymphoma 2 (BCL-2) ovarian killer (BOK) is a BCL-2 family protein with high homology to the multidomain proapoptotic proteins BAX and BAK, yet Bok−/− and even Bax−/−Bok−/− and Bak−/−Bok−/− mice were reported to have no overt phenotype or apoptotic defects in response to a host of classical stress stimuli. These surprising findings were interpreted to reflect functional compensation among the BAX, BAK, and BOK proteins. However, BOK cannot compensate for the severe apoptotic defects of Bax−/−Bak−/− mice despite its widespread expression. Here, we independently developed Bok−/− mice and found that Bok−/− cells are selectively defective in their response to endoplasmic reticulum (ER) stress stimuli, consistent with the predominant subcellular localization of BOK at the ER. Whereas Bok−/− mouse embryonic fibroblasts exposed to thapsigargin, A23187, brefeldin A, DTT, geldanamycin, or bortezomib manifested reduced activation of the mitochondrial apoptotic pathway, the death response to other stimuli such as etoposide, staurosporine, or UV remained fully intact. Multiple organs in Bok−/− mice exhibited resistance to thapsigargin-induced apoptosis in vivo. Although the ER stress agents activated the unfolded protein response, both ATF4 and CHOP activation were diminished in Bok−/− cells and mice. Importantly, BAX and BAK were unable to compensate for the defective apoptotic response to ER stress observed in SV40-transformed and primary Bok−/− cells, and in vivo. These findings support a selective and distinguishing role for BOK in regulating the apoptotic response to ER stress, revealing—to our knowledge—the first bona fide apoptotic defect linked to Bok deletion. PMID:26015568

  14. The targeted inhibition of mitochondrial Hsp90 overcomes the apoptosis resistance conferred by Bcl-2 in Hep3B cells via necroptosis

    SciTech Connect

    Yan, Chunlan; Oh, Joon Seok; Yoo, Seung Hee; Lee, Jee Suk; Yoon, Young Geol; Oh, Yoo Jin; Jang, Min Seok; Lee, Sang Yeob; Yang, Jun; Lee, Sang Hwa; Kim, Hye Young; Yoo, Young Hyun

    2013-01-01

    Previous studies have reported that a Gamitrinib variant containing triphenylphosphonium (G-TPP) binds to mitochondrial Hsp90 and rapidly inhibits its activity, thus inducing the apoptotic pathway in the cells. Accordingly, G-TPP shows a potential as a promising drug for the treatment of cancer. A cell can die from different types of cell death such as apoptosis, necrosis, necroptosis, and autophagic cell death. In this study, we further investigated the mechanisms and modes of cell death in the G-TPP-treated Hep3B and U937 cell lines. We discovered that G-TPP kills the U937 cells through the apoptotic pathway and the overexpression of Bcl-2 significantly inhibits U937 cell death to G-TPP. We further discovered that G-TPP kills the Hep3B cells by activating necroptosis in combination with the partial activation of caspase-dependent apoptosis. Importantly, G-TPP overcomes the apoptosis resistance conferred by Bcl-2 in Hep3B cells via necroptosis. We also observed that G-TPP induces compensatory autophagy in the Hep3B cell line. We further found that whereas there is a Bcl-2-Beclin 1 interaction in response to G-TPP, silencing the beclin 1 gene failed to block LC3-II accumulation in the Hep3B cells, indicating that G-TPP triggers Beclin 1-independent protective autophagy in Hep3B cells. Taken together, these data reveal that G-TPP induces cell death through a combination of death pathways, including necroptosis and apoptosis, and overcomes the apoptosis resistance conferred by Bcl-2 in Hep3B cells via necroptosis. These findings are important for the therapeutic exploitation of necroptosis as an alternative cell death program to bypass the resistance to apoptosis. Highlights: ► G-TPP binds to mitochondrial Hsp90. ► G-TPP induces apoptosis in U937 human leukemia cancer cells. ► G-TPP induces combination of death pathways in Hep3B cell. ► G-TPP overcomes the resistance conferred by Bcl-2 in Hep3B cells via necroptosis. ► G-TPP triggers Beclin 1-independent

  15. Clinical significance of Cox-2, Survivin and Bcl-2 expression in hepatocellular carcinoma (HCC).

    PubMed

    Yang, Yu; Zhu, Jiang; Gou, Hongfeng; Cao, Dan; Jiang, Ming; Hou, Mei

    2011-09-01

    Cox-2, Survivin and Bcl-2 are frequently overexpressed in numerous types of cancers. They are known to be the important regulators of apoptosis. This study was designed to investigate the correlation between the clinical characteristics and the expression of Cox-2, Survivin and Bcl-2 in hepatocellular carcinoma. A total of 63 postoperative hepatocellular carcinoma (HCC) samples, 10 adjacent non-tumor samples and 10 normal liver samples were immunochemically detected for the expression of Cox-2, Survivin and Bcl-2. A median follow-up of 4 years for the 63 HCC patients was conducted. Univariate tests and multivariate Cox regression were performed for statistical analysis. The Kaplan-Meier method was used to analyze the survival. Positive expression of Cox-2 (84.3%) and Survivin (77.8%) was detected significantly more frequently in the HCC samples than in the normal liver tissues (30% and 0, respectively). Bcl-2 was highly expressed in the adjacent non-tumor tissue. Cox-2 was positively correlative to Survivin. Survivin and Bcl-2 were significantly associated with the pathological grade of HCC (P<0.05). Expression of both Cox-2 and Survivin was significantly associated with the poor overall survival (OS) (P=0.0141, P=0.0039). Furthermore, multivariate analysis confirmed the independent prognostic value of Survivin expression, along with tumor size and hepatic function. Cox-2 and Survivin were highly expressed in the HCC tissue. Survivin and Bcl-2 were significantly associated with the pathological grade of HCC. The expression of Survivin was an independent prognostic factor for HCC after a hepatectomy. Treatment that inhibits Survivin may be a promising targeted approach in HCC.

  16. The Bcl-2-associated death promoter (BAD) lowers the threshold at which the Bcl-2-interacting domain death agonist (BID) triggers mitochondria disintegration.

    PubMed

    Howells, Christopher C; Baumann, William T; Samuels, David C; Finkielstein, Carla V

    2011-02-21

    The Bcl-2-associated death promoter (BAD) protein, like many other BH3-only proteins, is known to promote apoptosis through the intrinsic mitochondrial pathway. Unlike the BH3-interacting domain death agonist (BID) protein, BAD cannot directly trigger apoptosis but, instead, lowers the threshold at which apoptosis is induced. In many mathematical models of apoptosis, BAD is neglected or abstracted. The work presented here considers the incorporation of BAD and its various modifications in a model of the tBID-induction of BAK (Bcl-2 homologous antagonist killer) or the tBID-induction of BAX (Bcl-2-associated X protein). Steady state equations are used to develop an explicit formula describing the total concentration level of tBID, guaranteed to trigger apoptosis, as a bilinear function of the total BAD concentration level and the total anti-apoptotic protein concentration level (usually Bcl-2 or Bcl-xL). In particular, the formula explains how the pro-apoptotic protein BAD lowers the threshold at which tBID induces BAK/BAX activation-reducing the level of total Bcl-2/Bcl-xL available to inhibit tBID signaling in the mitochondria. Attention is then turned to the experimental data surrounding BAD phosphorylation, a process known to inhibit the pro-apoptotic effects of BAD. To address this data, the phosphorylation process is modeled following two separate kinetics in which either free unbound BAD is the assumed substrate or Bcl-xL/Bcl-2-bound BAD is the assumed substrate. Bifurcation analysis and further analysis of the bilinear equation validate experiments, which suggest that BAD phosphorylation prevents irreversible BAK/BAX-mediated apoptosis, even when phosphorylation-induced dissociation of Bcl-xL/Bcl-2-bound BAD is blocked. It is also shown that a cooperative, even synergistic, removal of mitochondrial BAD is seen when both types of phosphorylation are assumed possible. The presented work, however, reveals that the balance between BAD phosphorylation and

  17. The contribution of c-Jun N-terminal kinase activation and subsequent Bcl-2 phosphorylation to apoptosis induction in human B-cells is dependent on the mode of action of specific stresses

    SciTech Connect

    Muscarella, Donna E. Bloom, Stephen E.

    2008-04-01

    The c-Jun N-terminal kinase (JNK) pathway can play paradoxical roles as either a pro-survival or a pro-cell death pathway depending on type of stress and cell type. The goal of the present study was to determine the role of JNK pathway signaling for regulating B-cell apoptosis in two important but contrasting situations-global proteotoxic damage, induced by arsenite and hyperthermia, versus specific microtubule inhibition, induced by the anti-cancer drug vincristine, using the EW36 B-cell line. This cell line over-expresses the Bcl-2 protein and is a useful model to identify treatments that can overcome multi-drug resistance in lymphoid cells. Exposure of EW36 B-cells to arsenite or lethal hyperthermia resulted in activation of the JNK pathway and induction of apoptosis. However, pharmacological inhibition of the JNK pathway did not inhibit apoptosis, indicating that JNK pathway activation is not required for apoptosis induction by these treatments. In contrast, vincristine treatment of EW36 B-cells resulted in JNK activation and apoptosis that was suppressed by JNK inhibition. A critical difference between the two types of stress treatments was that only vincristine-induced JNK activation resulted in phosphorylation of Bcl-2 at threonine-56, a modification that can block its anti-apoptotic function. Importantly, Bcl-2 phosphorylation was attenuated by JNK inhibition implicating JNK as the upstream kinase. Furthermore, arsenite and hyperthermia treatments activated a p53/p21 pathway associated with apoptosis induction, whereas vincristine did not activate this pathway. These results reveal two stress-activated pathways, one JNK-dependent and another JNK-independent, either of which can bypass Bcl-2 mediated resistance, resulting in cell death.

  18. Bcl-2 Antagonists: A Proof of Concept for CLL Therapy

    PubMed Central

    Balakrishnan, Kumudha; Gandhi, Varsha

    2014-01-01

    Defective apoptosis is a fundamental hallmark feature of CLL biology and is a major target of cancer therapy development. High levels of Bcl-2 family anti-apoptotic proteins are considered primarily responsible for inhibiting apoptosis in CLL cells. While several approaches were considered to selectively inhibit Bcl-2 family anti-apoptotic proteins, the discovery that gossypol binds and antagonizes anti-apoptotic effect of Bcl-2 family proteins was a major breakthrough in identifying specific Bcl-2 antagonists. The concept of mimicking BH3 domain emphasized the importance of Bcl-2 family-targeted therapy that can modulate the function of anti-apoptotic proteins. Although parent compound gossypol did not sustain in the clinic, its structural modifications led to the development of additional analogues that demonstrated improved efficacy and reduced toxicity in preclinical and clinical investigations. Proof of concept of this hypothesis was demonstrated by structure based BH3 mimetic ABT-737 that has shown greater cytotoxicity towards CLL cells both in pre-clinical models and clinical trials. Its oral compound ABT-263 has demonstrated the substantial susceptibility of chronic lymphocytic leukemia cells through Bcl-2 inhibition. Collectively, results of a Phase I Study of Navitoclax (ABT-263) in patients with relapsed or refractory disease warrants Bcl-2 as a valid therapeutic target in CLL. Importantly, molecules that mimic pro-apoptotic BH3 domains represent a direct approach to overcoming the protective effects of anti-apoptotic proteins such as Mcl-1, Bcl-2 and Bcl-XL. PMID:23907405

  19. Initiation of premature senescence by Bcl-2 in hypoxic condition.

    PubMed

    Wang, Wei; Wang, Desheng; Li, Hong

    2014-01-01

    Senescence, a state of cell cycle arrest, has been regarded as an intrinsic barrier to malignance. Although being repressed in most immortal tumors, the genetic program of senescence can be reactivated by critical regulators, including the apoptosis regulator Bcl-2. We showed here that hypoxic condition resulted in an irreversible senescence-like phenotype with increased expression of Bcl-2 in mouse melanoma B16 cells. In CoCl2-simulating hypoxic condition, characteristic morphological alterations and increased activity of senescence-associated β-galactosidase (SA-β-gal) can be detected with high level of Bcl-2, which was confirmed by western blot and co-staining of SA-β-gal and Bcl-2 by immunocytochemistry. Accordingly, Bcl-2 silence by specific siRNA ahead of hypoxia treatment interrupted the senescent development. Moreover Bcl-2 overexpression led to early onset of senescence. We propose that Bcl-2 is required to initiate and maintain the senescent phenotype. In addition, p53 and p16 were not involved in hypoxia-induced senescence according to the expression levels during senescent process. These results suggest that when encountering harmful stress (hypoxia), melanoma cells overexpress Bcl-2 and turn to senescence, a permanent cell-cycle arrest, for prolonged survival.

  20. Expression of the bcl-2 gene product in follicular lymphoma.

    PubMed Central

    Gaulard, P.; d'Agay, M. F.; Peuchmaur, M.; Brousse, N.; Gisselbrecht, C.; Solal-Celigny, P.; Diebold, J.; Mason, D. Y.

    1992-01-01

    Expression of bcl-2 protein was analyzed in 140 cases of follicular lymphoma by immunohistologic staining of paraffin-embedded tissue; 85% of cases were positive, the frequency being related to histologic grade (100% for the small-cleaved cell type, 86% for the mixed cell type, and 76% for the large cell group). There was striking heterogeneity of bcl-2 content in a number of cases and the smaller neoplastic cells (i.e., centrocytes) were usually the most strongly labeled. In most cases, bcl-2 protein staining was much weaker in normal lymphoid cells than in the neoplastic cells. In several cases, staining for bcl-2 revealed patterns of neoplastic cell spread into adjacent tissue (e.g., normal follicles, lymphoid sinuses), and bcl-2 protein expression tended to be highest in these migratory cells. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 PMID:1374590

  1. Reconstitution of the anti-apoptotic Bcl-2 protein into lipid membranes and biophysical evidence for its detergent-driven association with the pro-apoptotic Bax protein.

    PubMed

    Wallgren, Marcus; Lidman, Martin; Pedersen, Anders; Brännström, Kristoffer; Karlsson, B Göran; Gröbner, Gerhard

    2013-01-01

    The anti-apoptotic B-cell CLL/lymphoma-2 (Bcl-2) protein and its counterpart, the pro-apoptotic Bcl-2-associated X protein (Bax), are key players in the regulation of the mitochondrial pathway of apoptosis. However, how they interact at the mitochondrial outer membrane (MOM) and there determine whether the cell will live or be sentenced to death remains unknown. Competing models have been presented that describe how Bcl-2 inhibits the cell-killing activity of Bax, which is common in treatment-resistant tumors where Bcl-2 is overexpressed. Some studies suggest that Bcl-2 binds directly to and sequesters Bax, while others suggest an indirect process whereby Bcl-2 blocks BH3-only proteins and prevents them from activating Bax. Here we present the results of a biophysical study in which we investigated the putative interaction of solubilized full-length human Bcl-2 with Bax and the scope for incorporating the former into a native-like lipid environment. Far-UV circular dichroism (CD) spectroscopy was used to detect direct Bcl-2-Bax-interactions in the presence of polyoxyethylene-(23)-lauryl-ether (Brij-35) detergent at a level below its critical micelle concentration (CMC). Additional surface plasmon resonance (SPR) measurements confirmed this observation and revealed a high affinity between the Bax and Bcl-2 proteins. Upon formation of this protein-protein complex, Bax also prevented the binding of antimycin A2 (a known inhibitory ligand of Bcl-2) to the Bcl-2 protein, as fluorescence spectroscopy experiments showed. In addition, Bcl-2 was able to form mixed micelles with Triton X-100 solubilized neutral phospholipids in the presence of high concentrations of Brij-35 (above its CMC). Following detergent removal, the integral membrane protein was found to have been fully reconstituted into a native-like membrane environment, as confirmed by ultracentrifugation and subsequent SDS-PAGE experiments.

  2. The intracellular distribution and pattern of expression of Mcl-1 overlap with, but are not identical to, those of Bcl-2

    PubMed Central

    1995-01-01

    A family of genes related to the bcl-2 protooncogene has recently emerged. One member of this family, mcl-1, was cloned from a human myeloblastic leukemia cell line (ML-1) undergoing differentiation. The intracellular localization of mcl-1, as well as the kinetics of its expression during differentiation, have now been studied. These studies show that the intracellular distribution of mcl-1 overlaps with, but is not identical to, that of bcl-2: mcl-1 is similar to bcl-2 in that the mcl-1 protein has a prominent mitochondrial localization, and in that it associates with membranes through its carboxyl hydrophobic tail. mcl- 1 differs from bcl-2, however, in its relative distribution among other (nonmitochondrial/heavy membrane) compartments, mcl-1 also being abundant in the light membrane fraction of immature ML-1 cells while bcl-2 is abundant in the nuclear fraction. Similarly, in differentiating ML-1 cells, the timing of expression of mcl-1 overlaps with, but is not identical to, that of bcl-2: the mcl-1 protein increases rapidly as cells initiate differentiation, and mcl-1 is a labile protein. In contrast, bcl-2 decreases gradually as cells complete differentiation. Overall, the mcl-1 and bcl-2 proteins have some properties in common and others tht are distinct. A burst of expression of mcl-1, prominently associated with mitochondria, complements the continued expression of bcl-2 in ML-1 cells differentiating along the monocyte/macrophage pathway. PMID:7896880

  3. Role of the Bcl-2 gene family in prostate cancer progression and its implications for therapeutic intervention.

    PubMed Central

    Chaudhary, K S; Abel, P D; Lalani, E N

    1999-01-01

    Prostate cancer (PC) is an escalating health burden in the western world. A large number of patients still present with extraprostatic (i.e., T3/T4, N0, M0/M1 or any T category and M1 disease or involved lymph nodes) and therefore incurable disease. Since the work of Huggins in 1940, there have been no major therapeutic advances and androgen ablation remains the best treatment option for extraprostatic androgen-responsive PC. Eighty to ninety percent of PC patients respond well to this form of treatment initially. After a median time of approximately 2 years, however, relapse to an androgen-independent (AI) state occurs, followed by death after a further median 6 months. Androgen ablation is rarely curative. The major molecular defect in extraprostatic and AI PC is the inability of PC cells to initiate apoptosis in response to a variety of stimuli, including different forms of androgen ablation and cytotoxic agents. The balance between cellular proliferation and cell death is regulated by multiple genes or families of genes through the cell cycle. The exact mechanisms governing this intricate and complex process are as yet not fully understood. One family of genes involved in cell survival/death control is the Bcl-2 gene family, which consists of homologous proteins that function to regulate distal and crucial commitment steps of the apoptotic pathway. The Bcl-2 family constitutes both agonists and antagonists of apoptosis that function at least in part through protein-protein interactions between various members of the family. The final outcome depends on the relative ratio of death agonists and antagonists. Bcl-2 expression has been closely associated with the AI phenotype of PC. Cytotoxic chemotherapy may be used as palliative therapy in AI PC but has not been found effective. Most chemotherapeutic cytotoxic agents induce apoptosis in cancer cells by direct and indirect action on the cell cycle. In vitro and in vivo studies have established that Bcl-2 expression

  4. Bcl-2 inhibits the mitochondrial release of an apoptogenic protease

    PubMed Central

    1996-01-01

    Bcl-2 belongs to a family of apoptosis-regulatory proteins which incorporate into the outer mitochondrial as well as nuclear membranes. The mechanism by which the proto-oncogene product Bcl-2 inhibits apoptosis is thus far elusive. We and others have shown previously that the first biochemical alteration detectable in cells undergoing apoptosis, well before nuclear changes become manifest, is a collapse of the mitochondrial inner membrane potential (delta psi m), suggesting the involvement of mitochondrial products in the apoptotic cascade. Here we show that mitochondria contain a pre-formed approximately 50-kD protein which is released upon delta psi m disruption and which, in a cell-free in vitro system, causes isolated nuclei to undergo apoptotic changes such as chromatin condensation and internucleosomal DNA fragmentation. This apoptosis-inducing factor (AIF) is blocked by N- benzyloxycarbonyl-Val-Ala-Asp.fluoromethylketone (Z-VAD.fmk), an antagonist of interleukin-1 beta-converting enzyme (ICE)-like proteases that is also an efficient inhibitor of apoptosis in cells. We have tested the effect of Bcl-2 on the formation, release, and action of AIF. When preventing mitochondrial permeability transition (which accounts for the pre-apoptotic delta psi m disruption in cells), Bcl-2 hyperexpressed in the outer mitochondrial membrane also impedes the release of AIF from isolated mitochondria in vitro. In contrast, Bcl-2 does not affect the formation of AIF, which is contained in comparable quantities in control mitochondria and in mitochondria from Bcl-2- hyperexpressing cells. Furthermore, the presence of Bcl-2 in the nuclear membrane does not interfere with the action of AIF on the nucleus, nor does Bcl-2 hyperexpression protect cells against AIF. It thus appears that Bcl-2 prevents apoptosis by favoring the retention of an apoptogenic protease in mitochondria. PMID:8879205

  5. Bcl-2 engineered MSCs inhibited apoptosis and improved heart function.

    PubMed

    Li, Wenzhong; Ma, Nan; Ong, Lee-Lee; Nesselmann, Catharina; Klopsch, Christian; Ladilov, Yury; Furlani, Dario; Piechaczek, Christoph; Moebius, Jeannette M; Lützow, Karola; Lendlein, Andreas; Stamm, Christof; Li, Ren-Ke; Steinhoff, Gustav

    2007-08-01

    Engraftment of mesenchymal stem cells (MSCs) derived from adult bone marrow has been proposed as a potential therapeutic approach for postinfarction left ventricular dysfunction. However, limited cell viability after transplantation into the myocardium has restricted its regenerative capacity. In this study, we genetically modified MSCs with an antiapoptotic Bcl-2 gene and evaluated cell survival, engraftment, revascularization, and functional improvement in a rat left anterior descending ligation model via intracardiac injection. Rat MSCs were manipulated to overexpress the Bcl-2 gene. In vitro, the antiapoptotic and paracrine effects were assessed under hypoxic conditions. In vivo, the Bcl-2 gene-modified MSCs (Bcl-2-MSCs) were injected after myocardial infarction. The surviving cells were tracked after transplantation. Capillary density was quantified after 3 weeks. The left ventricular function was evaluated by pressure-volume loops. The Bcl-2 gene protected MSCs against apoptosis. In vitro, Bcl-2 overexpression reduced MSC apoptosis by 32% and enhanced vascular endothelial growth factor secretion by more than 60% under hypoxic conditions. Transplantation with Bcl-2-MSCs increased 2.2-fold, 1.9-fold, and 1.2-fold of the cellular survival at 4 days, 3 weeks, and 6 weeks, respectively, compared with the vector-MSC group. Capillary density in the infarct border zone was 15% higher in Bcl-2-MSC transplanted animals than in vector-MSC treated animals. Furthermore, Bcl-2-MSC transplanted animals had 17% smaller infarct size than vector-MSC treated animals and exhibited functional recovery remarkably. Our current findings support the premise that transplantation of antiapoptotic gene-modified MSCs may have values for mediating substantial functional recovery after acute myocardial infarction.

  6. ABT-199 (venetoclax) and BCL-2 inhibitors in clinical development.

    PubMed

    Cang, Shundong; Iragavarapu, Chaitanya; Savooji, John; Song, Yongping; Liu, Delong

    2015-11-20

    With the advent of new agents targeting CD20, Bruton's tyrosine kinase, and phosphoinositol-3 kinase for chronic lymphoid leukemia (CLL), more treatment options exist than ever before. B-cell lymphoma-2 (BCL-2) plays a major role in cellular apoptosis and is a druggable target. Small molecule inhibitors of BCL-2 are in active clinical studies. ABT-199 (venetoclax, RG7601, GDC-0199) has been granted breakthrough designation by FDA for relapsed or refractory CLL with 17p deletion. In this review, we summarized the latest clinical development of ABT-199/venetoclax and other novel agents targeting the BCL-2 proteins.

  7. Increased expression of Bcl-2 during mucous cell metaplasia induced by endotoxin and ozone

    SciTech Connect

    Tesfaigzi, J.; Ray, L.M.; Hotchkiss, J.A.

    1995-12-01

    Apoptosis or programmed cell death is accompanied by characteristic morphological changes that distinguish apoptosis from other forms of cell death. These changes include DNA fragmentation, chromatin condensation, cell shrinkage, cell surface pseudopodia, and finally the cellular collapse into membrane-enclosed apoptotic bodies which are rapidly engulfed by macrophages or neighboring cells. Although the morphological features of apoptotic cells are well studied, the biochemical events that control apoptosis are not understood. Programmed cell death is triggered by a variety of pathways that are initiated by different stimuli including noxious agents, DNA damage, the activation of TNF receptors, or the withdrawl of growth factors. The central process of programmed cell death involves a cascade of biochemical events that begins with the initiation of a family of cysteine proteases, including the interleukin-1-{Beta}-converting enzyme, CPP-32, and Apopain. The ratio of Bax, a death-inducer gene, to Bcl-2, an apoptosis suppressor gene, determines whether or not the main apoptotic pathyway is blocked. Apoptosis is suppressed if the ratio of Bcl-2/Bax is > 1, and cells undergo apoptosis if the ratio is < 1. The overexpression of Bcl-2 has been shown to block the apoptotic program triggered by a variety of agents. Therefore, Bcl-2 must be involved in blocking the central pathway of the cell death program. In conclusion, this study showed that high levels of Bcl-2 were detected in some mucous cells at specific time points during mucous cell metaplasia, and this expression was reduced at later time points or was absent after remodeling of this epithelium.

  8. The Bcl-2 homology domain 3 (BH3)-only proteins Bim and bid are functionally active and restrained by anti-apoptotic Bcl-2 family proteins in healthy liver.

    PubMed

    Kodama, Takahiro; Hikita, Hayato; Kawaguchi, Tsukasa; Saito, Yoshinobu; Tanaka, Satoshi; Shigekawa, Minoru; Shimizu, Satoshi; Li, Wei; Miyagi, Takuya; Kanto, Tatsuya; Hiramatsu, Naoki; Tatsumi, Tomohide; Takehara, Tetsuo

    2013-10-18

    An intrinsic pathway of apoptosis is regulated by the B-cell lymphoma-2 (Bcl-2) family proteins. We previously reported that a fine rheostatic balance between the anti- and pro-apoptotic multidomain Bcl-2 family proteins controls hepatocyte apoptosis in the healthy liver. The Bcl-2 homology domain 3 (BH3)-only proteins set this rheostatic balance toward apoptosis upon activation in the diseased liver. However, their involvement in healthy Bcl-2 rheostasis remains unknown. In the present study, we focused on two BH3-only proteins, Bim and Bid, and we clarified the Bcl-2 network that governs hepatocyte life and death in the healthy liver. We generated hepatocyte-specific Bcl-xL- or Mcl-1-knock-out mice, with or without disrupting Bim and/or Bid, and we examined hepatocyte apoptosis under physiological conditions. We also examined the effect of both Bid and Bim disruption on the hepatocyte apoptosis caused by the inhibition of Bcl-xL and Mcl-1. Spontaneous hepatocyte apoptosis in Bcl-xL- or Mcl-1-knock-out mice was significantly ameliorated by Bim deletion. The disruption of both Bim and Bid completely prevented hepatocyte apoptosis in Bcl-xL-knock-out mice and weakened massive hepatocyte apoptosis via the additional in vivo knockdown of mcl-1 in these mice. Finally, the hepatocyte apoptosis caused by ABT-737, which is a Bcl-xL/Bcl-2/Bcl-w inhibitor, was completely prevented in Bim/Bid double knock-out mice. The BH3-only proteins Bim and Bid are functionally active but are restrained by the anti-apoptotic Bcl-2 family proteins under physiological conditions. Hepatocyte integrity is maintained by the dynamic and well orchestrated Bcl-2 network in the healthy liver.

  9. In vivo expression of p53 and Bcl-2 and their role in programmed cell death in premalignant and malignant lung lesions.

    PubMed

    Koty, Patrick P; Zhang, Haifan; Franklin, Wilbur A; Yousem, Samuel A; Landreneau, Rodney; Levitt, Mark L

    2002-02-01

    Forty-four specimens of non-malignant and malignant human lung tissue, taken from patients with non-small cell lung cancer (NSCLC), were examined for the expression of wild-type p53, mutant p53, and bcl-2 and the occurrence of programmed cell death (apoptosis). Wild-type p53 expression peaked in peritumoral and metaplastic samples, whereas mutant p53, bcl-2 and apoptosis were first detected in metaplasia and increased with progression to carcinoma. Bcl-2 positive samples had lower levels of apoptosis than bcl-2 negative samples and was independent of wild-type or mutant p53 expression. These results suggest that the over-expression of wild-type p53 may be an early cellular response to an alteration in normal cellular homeostasis. The ensuing increase in apoptosis appears to be relatively independent of mutant or wild-type p53 expression, but does not occur in cells expressing bcl-2.

  10. Bruton's tyrosine kinase inhibition increases BCL-2 dependence and enhances sensitivity to venetoclax in chronic lymphocytic leukemia.

    PubMed

    Deng, J; Isik, E; Fernandes, S M; Brown, J R; Letai, A; Davids, M S

    2017-02-14

    Although the BTK inhibitor ibrutinib has transformed the management of patients with chronic lymphocytic leukemia (CLL), it does not induce substantial apoptosis in vitro, and as such the mechanisms underlying its ability to kill CLL cells are not well understood. Acalabrutinib, a more specific BTK inhibitor now in development, also appears to be highly effective in CLL, but the connection of its mechanism with CLL cell death is also unclear. Using dynamic BH3 profiling, we analyzed alterations in the function of the mitochondrial apoptotic pathway induced by ibrutinib and acalabrutinib. We studied CLL patient samples treated ex vivo with both drugs, as well as primary samples from CLL patients on clinical trials of both drugs. We found that BTK inhibition enhances mitochondrial BCL-2 dependence without significantly altering overall mitochondrial priming. Enhancement of BCL-2 dependence was accompanied by an increase in the pro-apoptotic protein BIM. In contrast, treatment with the selective BCL-2 inhibitor venetoclax enhanced overall mitochondrial priming without increasing BCL-2 dependence. Pre-treatment of CLL cells with either BTK inhibitor, whether ex vivo or in vivo in patients, enhanced killing by venetoclax. Our data suggest that BTK inhibition enhances mitochondrial BCL-2 dependence, supporting the ongoing development of clinical trials combining BTK and BCL-2 inhibition.Leukemia advance online publication, 14 February 2017; doi:10.1038/leu.2017.32.

  11. Bad, a heterodimeric partner for Bcl-XL and Bcl-2, displaces Bax and promotes cell death.

    PubMed

    Yang, E; Zha, J; Jockel, J; Boise, L H; Thompson, C B; Korsmeyer, S J

    1995-01-27

    To extend the mammalian cell death pathway, we screened for further Bcl-2 interacting proteins. Both yeast two-hybrid screening and lambda expression cloning identified a novel interacting protein, Bad, whose homology to Bcl-2 is limited to the BH1 and BH2 domains. Bad selectively dimerized with Bcl-xL as well as Bcl-2, but not with Bax, Bcl-xs, Mcl-1, A1, or itself. Bad binds more strongly to Bcl-xL than Bcl-2 in mammalian cells, and it reversed the death repressor activity of Bcl-xL, but not that of Bcl-2. When Bad dimerized with Bcl-xL, Bax was displaced and apoptosis was restored. When approximately half of Bax was heterodimerized, death was inhibited. The susceptibility of a cell to a death signal is determined by these competing dimerizations in which levels of Bad influence the effectiveness of Bcl-2 versus Bcl-xL in repressing death.

  12. Bcl-2-related protein family gene expression during oligodendroglial differentiation.

    PubMed

    Itoh, Takayuki; Itoh, Aki; Pleasure, David

    2003-06-01

    Oligodendroglial lineage cells (OLC) vary in susceptibility to both necrosis and apoptosis depending on their developmental stages, which might be regulated by differential expression of Bcl-2-related genes. As an initial step to test this hypothesis, we examined the expression of 19 Bcl-2-related genes in purified cultures of rat oligodendroglial progenitors, immature and mature oligodendrocytes. All 'multidomain' anti-apoptotic members (Bcl-x, Bcl-2, Mcl-1, Bcl-w and Bcl2l10/Diva/Boo) except Bcl2a1/A1 are expressed in OLC. Semiquantitative and real-time RT-PCR revealed that Bcl-xL and Mcl-1 mRNAs are the dominant anti-apoptotic members and increase four- and twofold, respectively, with maturation. Bcl-2 mRNA is less abundant than Bcl-xL mRNA in progenitors and falls an additional 10-fold during differentiation. Bcl-w mRNA also increases, with significant changes in its splicing pattern, as OLC mature. Transfection studies demonstrated that Bcl-xL overexpression protects against kainate-induced excitotoxicity, whereas Bcl-2 overexpression does not. As for 'multidomain' pro-apoptotic members (Bax, Bad and Bok/Mtd), Bax and Bak are highly expressed throughout differentiation. Among 'BH3 domain-only' members examined (Bim, Biklk, DP5/Hrk, Bad, Bid, Noxa, Puma/Bbc3, Bmf, BNip3 and BNip3L), BNip3 and Bmf mRNAs increase markedly during differentiation. These results provide basic information to guide further studies on the roles for Bcl-2-related family proteins in OLC death.

  13. Non-apoptotic functions of BCL-2 family proteins.

    PubMed

    Gross, Atan; Katz, Samuel G

    2017-02-24

    The BCL-2 family proteins are major regulators of the apoptosis process, but the mechanisms by which they regulate this process are only partially understood. It is now well documented that these proteins play additional non-apoptotic roles that are likely to be related to their apoptotic roles and to provide important clues to cracking their mechanisms of action. It seems that these non-apoptotic roles are largely related to the activation of cellular survival pathways designated to maintain or regain cellular survival, but, if unsuccessful, will switch over into a pro-apoptotic mode. These non-apoptotic roles span a wide range of processes that include the regulation of mitochondrial physiology (metabolism, electron transport chain, morphology, permeability transition), endoplasmic reticulum physiology (calcium homeostasis, unfolded protein response (UPR)), nuclear processes (cell cycle, DNA damage response (DDR)), whole-cell metabolism (glucose and lipid), and autophagy. Here we review all these different non-apoptotic roles, make an attempt to link them to the apoptotic roles, and present many open questions for future research directions in this fascinating field.Cell Death and Differentiation advance online publication, 24 February 2017; doi:10.1038/cdd.2017.22.

  14. Bcl-2 and caspase-3 are major regulators in Agaricus blazei-induced human leukemic U937 cell apoptosis through dephoshorylation of Akt.

    PubMed

    Jin, Cheng-Yun; Moon, Dong-Oh; Choi, Yung Hyun; Lee, Jae-Dong; Kim, Gi-Young

    2007-08-01

    Agaricus blazei is a medicinal mushroom that possesses antimetastatic, antitumor, antimutagenic, and immunostimulating effects. However, the molecular mechanisms involved in A. blazei-mediated apoptosis remain unclear. In the present study, to elucidate the role of the Bcl-2 in A. blazei-mediated apoptosis, U937 cells were transfected with either empty vector (U937/vec) or vector containing cDNA encoding full-length Bcl-2 (U937/Bcl-2). As compared with U937/vec, U937/Bcl-2 cells exhibited a 4-fold greater expression of Bcl-2. Treatment of U937/vec with 1.0-4.0 mg/ml of A. blazei extract (ABE) for 24 h resulted in a significant induction of morphologic features indicative of apoptosis. In contrast, U937/Bcl-2 exposed to the same ABE treatment only exhibited a slight induction of apoptotic features. ABE-induced apoptosis was accompanied by downregulation of antiapoptotic proteins such as X-linked inhibitor of apoptosis protein (XIAP), inhibitor of apoptosis protein (cIAP)-2 and Bcl-2, activation of caspase-3, and cleavage of poly(ADP-ribose)polymerase (PARP). Ectopic expression of Bcl-2 was associated with significantly induced expression of antiapoptotic proteins, such as cIAP-2 and Bcl-2, but not XIAP. Ectopic expression of Bcl-2 also reduced caspase-3 activation and PARP cleavage in ABE treated U937 cells. Furthermore, treatment with the caspase-3 inhibitor z-DEVD-fmk was sufficient to restore cell viability following ABE treatment. This increase in viability was ascribed to downregulation of caspase-3 and blockage of PARP and PLC-gamma cleavage. ABE also triggered the downregulation of Akt, and combined treatment with LY294002 (an inhibitor of Akt) significantly decreased cell viability. The results indicated that major regulators of ABE-induced apoptosis in human leukemic U937 cells are Bcl-2 and caspase-3, which are associated with dephosphorylation of the Akt signal pathway.

  15. Quercetin induces apoptosis via caspase activation, regulation of Bcl-2, and inhibition of PI-3-kinase/Akt and ERK pathways in a human hepatoma cell line (HepG2).

    PubMed

    Granado-Serrano, Ana Belén; Martín, María Angeles; Bravo, Laura; Goya, Luis; Ramos, Sonia

    2006-11-01

    Dietary polyphenols have been associated with the reduced risk of chronic diseases such as cancer, but the precise underlying mechanism of protection remains unclear. The aim of this study was to investigate the effect of quercetin on the activation of the apoptotic pathway in a human hepatoma cell line (HepG2). Treatment of cells for 18 h with quercetin induced cell death in a dose-dependent manner; however, a shorter treatment (4 h) had no effect on cell viability. Incubation of HepG2 cells with quercetin for 18 h induced apoptosis by the activation of caspase-3 and -9, but not caspase-8. Moreover, this flavonoid decreased the Bcl-xL:Bcl-xS ratio and increased translocation of Bax to the mitochondrial membrane. A sustained inhibition of the major survival signals, Akt and extracellular regulated kinase (ERK), also occurred in quercetin-treated cells. These data suggest that quercetin may induce apoptosis by direct activation of caspase cascade (mitochondrial pathway) and by inhibiting survival signaling in HepG2.

  16. Bcl-2 expression during T-cell development: early loss and late return occur at specific stages of commitment to differentiation and survival.

    PubMed Central

    Gratiot-Deans, J; Merino, R; Nuñez, G; Turka, L A

    1994-01-01

    During T-cell development CD3-CD4-CD8- (double-negative) thymocytes proliferative and produce an enormous number of CD3loCD4+CD8+ (double-positive) thymocytes which are destined to die intrathymically unless rescued by positive selection. Those which survive become mature CD3hiCD4/8+ (single-positive) cells and are the precursor of peripheral blood lymphocytes. The product of the bcl-2 protooncogene has been implicated in preventing programmed cell death and is required for prolonged lymphocyte survival following maturation. Previously we and others have reported that Bcl-2 protein expression is biphasic, being high in proliferating double-negative stem cells, low in all double-positive thymocytes except for 1-5% of these cells, and restored in mature, single-positive thymocytes. However, it remained unclear which signaling and selection events regulate Bcl-2 during T-cell maturation. Now we have utilized four-color flow cytometry in normal and genetically altered mice for a detailed analysis of Bcl-2 expression as it relates to T-cell receptor (TCR) expression and positive selection. These studies show that (i) expression of a transgenic TCR in double-negative thymocytes does not lead to premature loss of Bcl-2; thus, Bcl-2 downregulation is not solely due to TCR expression; (ii) Bcl-2 expression is lost at the early transitional CD3-/loCD4-CD8+ stage, prior to expression of CD4; (iii) the Bcl-2+ double-positive thymocytes are those which have undergone positive selection; and (iv) upregulation of Bcl-2 during positive selection requires participation of the CD4 or CD8 co-receptor. These results demonstrate that Bcl-2 and TCR expression are regulated independently during T-cell development, and suggest a role for the CD4 or CD8 co-receptor in Bcl-2 induction during positive selection. Images PMID:7938012

  17. Inhibition of Mcl-1 with the pan-Bcl-2 family inhibitor (-)BI97D6 overcomes ABT-737 resistance in acute myeloid leukemia.

    PubMed

    Pan, Rongqing; Ruvolo, Vivian R; Wei, Jun; Konopleva, Marina; Reed, John C; Pellecchia, Maurizio; Andreeff, Michael; Ruvolo, Peter P

    2015-07-16

    Overexpression of antiapoptotic Bcl-2 proteins such as Bcl-2, Bcl-xL, and Mcl-1 is widely associated with tumor initiation, progression, and chemoresistance. Furthermore, it has been demonstrated that Mcl-1 upregulation renders several types of cancers resistant to the Bcl-2/Bcl-xL inhibitors ABT-737 and ABT-263. The emerging importance of Mcl-1 in pathogenesis and drug resistance makes it a high-priority therapeutic target. In this study, we showed that inhibition of Mcl-1 with a novel pan-Bcl-2 inhibitor (-)BI97D6 potently induced apoptosis in acute myeloid leukemia (AML) cells. (-)BI97D6 induced hallmarks of mitochondrial apoptosis, disrupted Mcl-1/Bim and Bcl-2/Bax interactions, and stimulated cell death via the Bak/Bax-dependent mitochondrial apoptosis pathway, suggesting on-target mechanisms. As a single agent, this pan-Bcl-2 inhibitor effectively overcame AML cell apoptosis resistance mediated by Mcl-1 or by interactions with bone marrow mesenchymal stromal cells. (-)BI97D6 was also potent in killing refractory primary AML cells. Importantly, (-)BI97D6 killed AML leukemia stem/progenitor cells while largely sparing normal hematopoietic stem/progenitor cells. These findings demonstrate that pan-Bcl-2 inhibition by an Mcl-1-targeting inhibitor not only overcomes intrinsic drug resistance ensuing from functional redundancy of Bcl-2 proteins, but also abrogates extrinsic resistance caused by the protective tumor microenvironment.

  18. Hormone-independent pathways of sexual differentiation.

    PubMed

    Renfree, Marilyn B; Chew, Keng Yih; Shaw, Geoffrey

    2014-01-01

    New observations over the last 25 years of hormone-independent sexual dimorphisms have gradually and unequivocally overturned the dogma, arising from Jost's elegant experiments in the mid-1900s, that all somatic sex dimorphisms in vertebrates arise from the action of gonadal hormones. Although we know that Sry, a Y-linked gene, is the primary gonadal sex determinant in mammals, more recent analysis in marsupials, mice, and finches has highlighted numerous sexual dimorphisms that are evident well before the differentiation of the testis and which cannot be explained by a sexually dimorphic hormonal environment. In marsupials, scrotal bulges and mammary primordia are visible before the testis has differentiated due to the expression of a gene(s) on the X chromosome. ZZ and ZW gynandromorph finches have brains that develop in a sexually dimorphic way dependent on their sex chromosome content. In genetically manipulated mice, it is the X chromosomes, not the gonads, that determine many characters including rate of early development, adiposity, and neural circuits. Even spotted hyenas have sexual dimorphisms that cannot be simply explained by hormonal exposure. This review discusses the recent findings that confirm that there are hormone-independent sexual dimorphisms well before the gonads begin to produce their hormones.

  19. Photoreactive stapled peptides to identify and characterize BCL-2 family interaction sites by mass spectrometry.

    PubMed

    Lee, Susan; Braun, Craig R; Bird, Gregory H; Walensky, Loren D

    2014-01-01

    Protein interactions dictate a myriad of cellular activities that maintain health or cause disease. Dissecting these binding partnerships, and especially their sites of interaction, fuels the discovery of signaling pathways, disease mechanisms, and next-generation therapeutics. We previously applied all-hydrocarbon peptide stapling to chemically restore α-helical shape to bioactive motifs that become unfolded when taken out of context from native signaling proteins. For example, we developed stabilized alpha-helices of BCL-2 domains (SAHBs) to dissect and target protein interactions of the BCL-2 family, a critical network that regulates the apoptotic pathway. SAHBs are α-helical surrogates that bind both stable and transient physiologic interactors and have effectively uncovered novel sites of BCL-2 family protein interaction. To leverage stapled peptides for proteomic discovery, we describe our conversion of SAHBs into photoreactive agents that irreversibly capture their protein targets and facilitate rapid identification of the peptide helix binding sites. We envision that the development of photoreactive stapled peptides will accelerate the discovery of novel and unanticipated protein interactions and how they impact health and disease.

  20. Autophagy regulates the post-translational cleavage of BCL-2 and promotes neuronal survival.

    PubMed

    Lossi, Laura; Gambino, Graziana; Salio, Chiara; Merighi, Adalberto

    2010-05-18

    B-cell lymphoma 2 protein (BCL-2) is one of the more widely investigated anti-apoptotic protein in mammals, and its levels are critical for protecting from programmed cell death. We report here that the cellular content of BCL-2 is regulated at post-translational level along the autophagy/lysosome pathways in organotypic cultures of post-natal mouse cerebellar cortex. Specifically this mechanism appears to be effective in the cerebellar granule cells (CGCs) that are known to undergo massive programmed cell death (apoptosis) during post-natal maturation. By the use of specific agonists/antagonist of calcium channels at the endoplasmic reticulum it was possible to understand the pivotal role of calcium release from intracellular stores in CGC neuroprotection. The more general significance of these findings is supported by a very recent study Niemann-Pick transgenic mice.

  1. BCL-2 family proteins as regulators of mitochondria metabolism.

    PubMed

    Gross, Atan

    2016-08-01

    The BCL-2 family proteins are major regulators of apoptosis, and one of their major sites of action are the mitochondria. Mitochondria are the cellular hubs for metabolism and indeed selected BCL-2 family proteins also possess roles related to mitochondria metabolism and dynamics. Here we discuss the link between mitochondrial metabolism/dynamics and the fate of stem cells, with an emphasis on the role of the BID-MTCH2 pair in regulating this link. We also discuss the possibility that BCL-2 family proteins act as metabolic sensors/messengers coming on and off of mitochondria to "sample" the cytosol and provide the mitochondria with up-to-date metabolic information. This article is part of a Special Issue entitled 'EBEC 2016: 19th European Bioenergetics Conference, Riva del Garda, Italy, July 2-6, 2016', edited by Prof. Paolo Bernardi.

  2. BH3-only proteins and BH3 mimetics induce autophagy by competitively disrupting the interaction between Beclin 1 and Bcl-2/Bcl-X(L).

    PubMed

    Maiuri, Maria Chiara; Criollo, Alfredo; Tasdemir, Ezgi; Vicencio, José Miguel; Tajeddine, Nicolas; Hickman, John A; Geneste, Olivier; Kroemer, Guido

    2007-01-01

    Beclin 1 has recently been identified as novel BH3-only protein, meaning that it carries one Bcl-2-homology-3 (BH3) domain. As other BH3-only proteins, Beclin 1 interacts with anti-apoptotic multidomain proteins of the Bcl-2 family (in particular Bcl-2 and its homologue Bcl-X(L)) by virtue of its BH3 domain, an amphipathic alpha-helix that binds to the hydrophobic cleft of Bcl-2/Bcl-X(L). The BH3 domains of other BH3-only proteins such as Bad, as well as BH3-mimetic compounds such as ABT737, competitively disrupt the inhibitory interaction between Beclin 1 and Bcl-2/Bcl-X(L). This causes autophagy of mitochondria (mitophagy) but not of the endoplasmic reticulum (reticulophagy). Only ER-targeted (not mitochondrion-targeted) Bcl-2/Bcl-X(L) can inhibit autophagy induced by Beclin 1, and only Beclin 1-Bcl-2/Bcl-X(L) complexes present in the ER (but not those present on heavy membrane fractions enriched in mitochondria) are disrupted by ABT737. These findings suggest that the Beclin 1-Bcl-2/Bcl-X(L) complexes that normally inhibit autophagy are specifically located in the ER and point to an organelle-specific regulation of autophagy. Furthermore, these data suggest a spatial organization of autophagy and apoptosis control in which BH3-only proteins exert two independent functions. On the one hand, they can induce apoptosis, by (directly or indirectly) activating the mitochondrion-permeabilizing function of pro-apoptotic multidomain proteins from the Bcl-2 family. On the other hand, they can activate autophagy by liberating Beclin 1 from its inhibition by Bcl-2/Bcl-X(L) at the level of the endoplasmic reticulum.

  3. Low incidence of MYC/BCL2 double-hit in Burkitt lymphoma.

    PubMed

    Yoshida, Maki; Ichikawa, Ayako; Miyoshi, Hiroaki; Kiyasu, Junichi; Kimura, Yoshizo; Niino, Daisuke; Ohshima, Koichi

    2015-09-01

    Translocations involving MYC are highly characteristic for Burkitt lymphoma (BL). BCL2 expression has also been found previously in about 10 to 20% of BL cases, and BCL2 translocation is a major mechanism for the deregulation of BCL2 expression in non-Hodgkin lymphomas. However, we know little about the incidence of MYC/BCL2 double-hit (DH) in BL. We examined BL cases to determine how frequently they contained BCL2 translocations in combination with MYC translocations using fluorescence in situ hybridization. We also determined the effect of BCL2 expression on clinical outcomes of BL. BCL2 translocations were detected in 3.5% (2/57 cases) of the cases, and BCL2 expression was detected in 33%. Two cases with BCL2 translocation also showed BCL2 expression. The incidence of BCL2 expression was significantly higher in patients 16 years of age and older (46%) than in patients under 16 years of age (6%). Among patients 16 years of age and older, we did not detect significant differences in overall survival with respect to BCL2 expression status. In conclusion, BCL2 translocation is a rare cytogenetic abnormality in BL, and BL probably accounts for only a small fraction of MYC/BCL2 DH lymphomas. BCL2 expression in BL is probably not associated with BCL2 translocations.

  4. BIM (BCL-2 interacting mediator of cell death) SAHB (stabilized α helix of BCL2) not always convinces BAX (BCL-2-associated X protein) for apoptosis.

    PubMed

    Verma, Sharad; Goyal, Sukriti; Tyagi, Chetna; Jamal, Salma; Singh, Aditi; Grover, Abhinav

    2016-06-01

    The interaction of BAX (BCL-2-associated X protein) with BIM (BCL-2 interacting mediator of cell death) SAHB (stabilized α helix of BCL2) directly initiates BAX-mediated mitochondrial apoptosis. This molecular dynamics study reveals that BIM SAHB forms a stable complex with BAX but it remains in a non-functional conformation. N terminal of BAX folds towards the core which has been reported exposed in the functional monomer. The α1-α2 loop, which has been reported in open conformation in functional BAX, acquires a closed conformation during the simulation. BH3/α2 remains less exposed as compared to initial structure. The hydrophobic residues of BIM accommodates in the rear pocket of BAX during the simulation. A steep decrease in radius of gyration and solvent accessible surface area (SASA) indicates the complex folding to acquire a more stable but inactive conformation. Further the covariance matrix reveals that the backbone atoms' motions favour the inactive conformation of the complex. This is the first report on the non-functional BAX-BIM SAHB complex by molecular dynamics simulation in the best of our knowledge.

  5. Discovery of a small-molecule pBcl-2 inhibitor that overcomes pBcl-2-mediated resistance to apoptosis.

    PubMed

    Song, Ting; Yu, Xiaoyan; Liu, Yubo; Li, Xiangqian; Chai, Gaobo; Zhang, Zhichao

    2015-03-23

    Although the role of Bcl-2 phosphorylation is still under debate, it has been identified in a resistance mechanism to BH3 mimetics, for example ABT-737 and S1. We identified an S1 analogue, S1-16, as a small-molecule inhibitor of pBcl-2. S1-16 efficiently kills EEE-Bcl-2 (a T69E, S70E, and S87E mutant mimicking phosphorylation)-expressing HL-60 cells and high endogenously expressing pBcl-2 cells, by disrupting EEE-Bcl-2 or native pBcl-2 interactions with Bax and Bak, followed by apoptosis. In vitro binding assays showed that S1-16 binds to the BH3 binding groove of EEE-Bcl-2 (Kd =0.38 μM by ITC; IC50 =0.16 μM by ELISA), as well as nonphosphorylated Bcl-2 (npBcl-2; Kd =0.38 μM; IC50 =0.12 μM). However, ABT-737 and S1 had much weaker affinities to EEE-Bcl-2 (IC50 =1.43 and >10 μM, respectively), compared with npBcl-2 (IC50 =0.011 and 0.74 μM, respectively). The allosteric effect on BH3 binding groove by Bcl-2 phosphorylation in the loop region was illustrated for the first time.

  6. Expression of the Bcl-2 family genes and complexes involved in the mitochondrial transport in prostate cancer cells.

    PubMed

    Asmarinah, Asmarinah; Paradowska-Dogan, Agnieszka; Kodariah, Ria; Tanuhardja, Budiana; Waliszewski, Przemyslaw; Mochtar, Chaidir Arif; Weidner, Wolfgang; Hinsch, Elvira

    2014-10-01

    Alteration of molecular pathways triggering apoptosis gives raise to various pathological tissue processes, such as tumorigenesis. The mitochondrial pathway is regulated by both the genes of the Bcl-2 family and the genes encoding mitochondrial transport molecules. Those proteins allow a release of cyctochrome c through the outer mitochondrial membrane. This release activates the caspase cascade resulting in death of cells. There are at least two main transport systems associated with the family of Bcl-2 proteins that are involved in transport of molecules through the outer mitochondrial membrane, i.e., the voltage dependent anion channels (VDACs) and translocases of the outer mitochondrial membrane proteins (TOMs). We investigated the expression of genes of the Bcl-2 family, i.e., pro-apoptotic Bak and Bid, and anti-apoptotic Bcl-2; VDAC gene, i.e., VDAC1, VDAC2 and VDAC3; and TOMM genes, i.e., TOMM20, TOMM22 and TOMM40. This study was performed at the mRNA and the protein level. Fourteen paraffin embedded prostate cancer tissues and five normal prostate tissues were analyzed by the quantitative PCR array and immunohistochemistry. We found a significant increase in both mRNA expression of the anti-apoptotic Bcl-2 gene and VDAC1 gene in prostate cancer tissue in comparison with their normal counterparts. Translation of the anti-apoptotic Bcl-2 and VDAC1 genes in prostate cancer tissue was slightly increased. We observed no significant differences in the mRNA expression of the pro-apoptotic Bak and Bid genes, VDAC2 or VDAC3 genes or the three TOMM genes in these tissues. The pro-apoptotic Bax protein was downtranslated significantly in secretory cells of prostate cancer as compared to normal prostate. We suggest that this protein is a good candidate as biomarker for prostate cancer.

  7. Concurrent Expression of MYC and BCL2 in Diffuse Large B-Cell Lymphoma Treated With Rituximab Plus Cyclophosphamide, Doxorubicin, Vincristine, and Prednisone

    PubMed Central

    Johnson, Nathalie A.; Slack, Graham W.; Savage, Kerry J.; Connors, Joseph M.; Ben-Neriah, Susana; Rogic, Sanja; Scott, David W.; Tan, King L.; Steidl, Christian; Sehn, Laurie H.; Chan, Wing C.; Iqbal, Javeed; Meyer, Paul N.; Lenz, Georg; Wright, George; Rimsza, Lisa M.; Valentino, Carlo; Brunhoeber, Patrick; Grogan, Thomas M.; Braziel, Rita M.; Cook, James R.; Tubbs, Raymond R.; Weisenburger, Dennis D.; Campo, Elias; Rosenwald, Andreas; Ott, German; Delabie, Jan; Holcroft, Christina; Jaffe, Elaine S.; Staudt, Louis M.; Gascoyne, Randy D.

    2012-01-01

    Purpose Diffuse large B-cell lymphoma (DLBCL) is curable in 60% of patients treated with rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP). MYC translocations, with or without BCL2 translocations, have been associated with inferior survival in DLBCL. We investigated whether expression of MYC protein, with or without BCL2 protein expression, could risk-stratify patients at diagnosis. Patients and Methods We determined the correlation between presence of MYC and BCL2 proteins by immunohistochemistry (IHC) with survival in two independent cohorts of patients with DLBCL treated with R-CHOP. We further determined if MYC protein expression correlated with high MYC mRNA and/or presence of MYC translocation. Results In the training cohort (n = 167), MYC and BCL2 proteins were detected in 29% and 44% of patients, respectively. Concurrent expression (MYC positive/BCL2 positive) was present in 21% of patients. MYC protein correlated with presence of high MYC mRNA and MYC translocation (both P < .001), but the latter was less frequent (both 11%). MYC protein expression was only associated with inferior overall and progression-free survival when BCL2 protein was coexpressed (P < .001). Importantly, the poor prognostic effect of MYC positive/BCL2 positive was validated in an independent cohort of 140 patients with DLBCL and remained significant (P < .05) after adjusting for presence of high-risk features in a multivariable model that included elevated international prognostic index score, activated B-cell molecular subtype, and presence of concurrent MYC and BCL2 translocations. Conclusion Assessment of MYC and BCL2 expression by IHC represents a robust, rapid, and inexpensive approach to risk-stratify patients with DLBCL at diagnosis. PMID:22851565

  8. Boolean network-based model of the Bcl-2 family mediated MOMP regulation

    PubMed Central

    2013-01-01

    Background Mitochondrial outer membrane permeabilization (MOMP) is one of the most important points in the majority of apoptotic signaling cascades and it is controlled by a network of interactions between the members of the Bcl-2 family. Methods To understand the role of individual members of this family within the MOMP regulation, we have constructed a Boolean network-based model of interactions between the Bcl-2 proteins. Results Computational simulations have revealed the existence of trapping states which, independently from the incoming stimuli, block the occurrence of MOMP. Our results emphasize the role of the antiapoptotic protein Mcl-1 in the majority of these configurations. We demonstrate here the importance of the Bid and Bim for activation of effectors Bax and Bak, and the irreversibility of this activation. The model further points to the antiapoptotic protein Bcl-w as a key factor preventing Bax activation. Conclusions In spite of relative simplicity, the Boolean network-based model provides useful insight into main functioning logic of the Bcl-2 switch, consistent with experimental findings. PMID:23767791

  9. Down-Regulation of MicroRNA-133b Suppresses Apoptosis of Lens Epithelial Cell by Up-Regulating BCL2L2 in Age-Related Cataracts

    PubMed Central

    Zhang, Feng; Meng, Weizhe; Tong, Bin

    2016-01-01

    Background MicroRNA-133b (miR-133b) has been reported to be involved in many diseases, including ovarian cancer and osteosarcoma. Accumulating evidence suggests that miR-133b plays important roles in human disease. In this study, we aimed to investigate the molecular mechanism, including the potential regulator and signaling pathways, of BCL2L2. Material/Methods We first searched the online miRNA database (www.mirdb.org) using the “seed sequence” located within the 3′-UTR of the target gene, and then performed luciferase assay to test the regulatory relationship between miR-133b and BCL2L2. Western blot and real-time PCR were used to determine the expression of BCL2L2 in human samples or cells treated with miRNA mimics or inhibitors. Flow cytometry was conducted to evaluate the apoptosis status of the cells. Results We validated BCL2L2 to be the direct gene using a luciferase reporter assay. We also conducted real-time PCR and Western blot analyses to study the mRNA and protein expression level of BCL2L2 among different groups (control: n=29, cataract: n=33) or cells treated with scramble control, miR-133b mimics, BCL2L2 siRNA, and miR-133b inhibitors, and identified the negative regulatory relationship between miR-133b and BCL2L2. We also conducted experiments to investigate the influence of miR-133b and BCL2L2 on the viability and apoptosis of cells. The results showed that miR-133b positively interfered with the viability of cells, while BCL2L2 negatively interfered with the viability of cells, and that miR-133b inhibited apoptosis while BCL2L2 accelerated apoptosis. Conclusions BCL2L2 was the virtual target of miR-133b, and we found a negative regulatory relationship between miR-133b and BCL2L2. MiR-133b and BCL2L2 interfered with the viability and apoptosis of cells. PMID:27802259

  10. Response of yeast to the regulated expression of proteins in the Bcl-2 family.

    PubMed Central

    Polcic, Peter; Forte, Michael

    2003-01-01

    The mechanisms by which pro-apoptotic members of the Bcl-2 family of proteins promote the release of mitochondrial factors like cytochrome c, subsequently activating the apoptotic cascade, or by which anti-apoptotic family members block this release, are still not understood. When expressed in yeast, Bcl-2 family members act directly upon conserved mitochondrial components that correspond to their apoptotic substrates in mammalian cells. Here we describe a system in which the levels of representative pro- and anti-apoptotic members of the Bcl-2 family can be regulated independently in yeast. Using this system, we have focused on the action of the anti-apoptotic family member Bcl-x(L), and have defined the quantitative relationships that underlie the antagonistic action of this protein on the lethal consequences of expression of the pro-apoptotic family member Bax. This system has also allowed us to demonstrate biochemically that Bcl-x(L) has two actions at the level of the mitochondrion. Bcl-x(L) is able to inhibit the stable integration of Bax into mitochondrial membranes, as well as hinder the action of Bax that does become stably integrated into these membranes. Taken together, our results suggest that both the functional and biochemical actions of Bcl-x(L) may be based on the ability of this molecule to disrupt the interaction of Bax with a resident mitochondrial target that is required for Bax action. Finally, we confirm that VDAC (voltage-dependent anion channel) is not required for the functional responses observed following the expression of either pro- or anti-apoptotic members of the Bcl-2 family. PMID:12780347

  11. SS-A/Ro52 promotes apoptosis by regulating Bcl-2 production

    SciTech Connect

    Jauharoh, Siti Nur Aisyah; Saegusa, Jun; Sugimoto, Takeshi; Ardianto, Bambang; Kasagi, Shimpei; Sugiyama, Daisuke; Kurimoto, Chiyo; Tokuno, Osamu; Nakamachi, Yuji; Kumagai, Shunichi; Kawano, Seiji

    2012-01-06

    Highlights: Black-Right-Pointing-Pointer Ro52{sup low} HeLa cells are resistant to apoptosis upon various stimulations. Black-Right-Pointing-Pointer Ro52 is upregulated by IFN-{alpha}, etoposide, or IFN-{gamma} and anti-Fas Ab. Black-Right-Pointing-Pointer Ro52-mediated apoptosis is independent of p53. Black-Right-Pointing-Pointer Ro52 selectively regulates Bcl-2 expression. -- Abstract: SS-A/Ro52 (Ro52), an autoantigen in systemic autoimmune diseases such as systemic lupus erythematosus and Sjoegren's syndrome, has E3 ligase activity to ubiquitinate proteins that protect against viral infection. To investigate Ro52's role during stress, we transiently knocked it down in HeLa cells by siRo52 transfection. We found that Ro52{sup low} HeLa cells were significantly more resistant to apoptosis than wild-type HeLa cells when stimulated by H{sub 2}O{sub 2}- or diamide-induced oxidative stress, IFN-{alpha}, IFN-{gamma} and anti-Fas antibody, etoposide, or {gamma}-irradiation. Furthermore, Ro52-mediated apoptosis was not influenced by p53 protein level in HeLa cells. Depleting Ro52 in HeLa cells caused Bcl-2, but not other Bcl-2 family molecules, to be upregulated. Taken together, our data showed that Ro52 is a universal proapoptotic molecule, and that its proapoptotic effect does not depend on p53, but is exerted through negative regulation of the anti-apoptotic protein Bcl-2. These findings shed light on a new physiological role for Ro52 that is important to intracellular immunity.

  12. The alpha1-adrenoceptor antagonist terazosin induces prostate cancer cell death through a p53 and Rb independent pathway.

    PubMed

    Xu, Kexin; Wang, Xianghong; Ling, Patrick M T; Tsao, S W; Wong, Y C

    2003-01-01

    Prostate cancer is the second leading cause of cancer-related death in men. Treatment failure in prostate cancer is usually due to the development of androgen independence and resistance to chemotherapeutic drugs at an advanced stage. Recently, it was reported that the alpha1-adrenoceptor antagonist terazosin was able to inhibit prostate cancer cell growth and indicated that it may have an implication in the treatment of prostate cancer. The aim of the present study was to investigate the mechanisms involved in terazosin-induced prostate cancer cell death using two androgen-independent cell lines, PC-3 and DU145. Our results showed that terazosin inhibited not only prostate cancer cell growth but also colony forming ability, which is the main target of chemotherapy. We also found that the sensitivity of these cells to terazosin was not affected by the presence of either functional p53 or Rb, suggesting that the terazosin-induced cell death was independent of p53 and Rb. However, the terazosin-induced cell death was associated with G1 phase cell cycle arrest and up-regulation of p27KIP1. In addition, up-regulation of Bax and down-regulation of Bcl-2 was also observed indicating that these two apoptotic regulators may play important roles in terazosin-mediated cell death pathway. Our results provide evidence for the first time that terazosin may have a therapeutic potential in the treatment of advanced prostate cancer.

  13. Caspase Induction and BCL2 Inhibition in Human Adipose Tissue

    PubMed Central

    Tinahones, Francisco José; Coín Aragüez, Leticia; Murri, Mora; Oliva Olivera, Wilfredo; Mayas Torres, María Dolores; Barbarroja, Nuria; Gomez Huelgas, Ricardo; Malagón, Maria M.; El Bekay, Rajaa

    2013-01-01

    OBJECTIVE Cell death determines the onset of obesity and associated insulin resistance. Here, we analyze the relationship among obesity, adipose tissue apoptosis, and insulin signaling. RESEARCH DESIGN AND METHODS The expression levels of initiator (CASP8/9) and effector (CASP3/7) caspases as well as antiapoptotic B-cell lymphoma (BCL)2 and inflammatory markers were assessed in visceral (VAT) and subcutaneous (SAT) adipose tissue from patients with different degrees of obesity and without insulin resistance or diabetes. Adipose tissue explants from lean subjects were cultured with TNF-α or IL-6, and the expression of apoptotic and insulin signaling components was analyzed and compared with basal expression levels in morbidly obese subjects. RESULTS SAT and VAT exhibited increased CASP3/7 and CASP8/9 expression levels and decreased BCL2 expression with BMI increase. These changes were accompanied by increased inflammatory cytokine mRNA levels and macrophage infiltration markers. In obese subjects, CASP3/7 activation and BCL2 downregulation correlated with the IRS-1/2–expression levels. Expression levels of caspases, BCL2, p21, p53, IRS-1/2, GLUT4, protein tyrosine phosphatase 1B, and leukocyte antigen-related phosphatase in TNF-α– or IL-6–treated explants from lean subjects were comparable with those found in adipose tissue samples from morbidly obese subjects. These insulin component expression levels were reverted with CASP3/7 inhibition in these TNF-α– or IL-6–treated explants. CONCLUSIONS Body fat mass increase is associated with CASP3/7 and BCL2 expression in adipose tissue. Moreover, this proapoptotic state correlated with insulin signaling, suggesting its potential contribution to the development of insulin resistance. PMID:23193206

  14. Differential effects of Bcl-2 and caspases on mitochondrial permeabilization during endogenous or exogenous reactive oxygen species-induced cell death: a comparative study of H₂O₂, paraquat, t-BHP, etoposide and TNF-α-induced cell death.

    PubMed

    Rincheval, Vincent; Bergeaud, Marie; Mathieu, Lise; Leroy, Jacqueline; Guillaume, Arnaud; Mignotte, Bernard; Le Floch, Nathalie; Vayssière, Jean-Luc

    2012-08-01

    In this study, we have compared several features of cell death triggered by classical inducers of apoptotic pathways (etoposide and tumour necrosis factor (TNF)-α) versus exogenous reactive oxygen species (ROS; hydrogen peroxide (H₂O₂), tert-butyl hydroperoxide (t-BHP)) or a ROS generator (paraquat). Our aim was to characterize relationships that exist between ROS, mitochondrial perturbations, Bcl-2 and caspases, depending on source and identity of ROS. First, we have found that these five inducers trigger oxidative stress, mitochondrial membrane permeabilization (MMP), cytochrome c (cyt c) release from mitochondria and cell death. In each case, cell death could be inhibited by several antioxidants, showing that it is primarily ROS dependent. Second, we have highlighted that during etoposide or TNF-α treatments, intracellular ROS level, MMP and cell death are all regulated by caspases and Bcl-2, with caspases acting early in the process. Third, we have demonstrated that H₂O₂-induced cell death shares many of these characteristics with etoposide and TNF-α, whereas t-BHP induces both caspase-dependent and caspase-independent cell death. Surprisingly, paraquat-induced cell death, which harbours some characteristics of apoptosis such as cyt c release and caspase-3 activation, is not modulated by Bcl-2 and caspase inhibitors, suggesting that paraquat also triggers non-apoptotic cell death signals. On the one hand, these results show that endogenous or exogenous ROS can trigger multiple cell death pathways with Bcl-2 and caspases acting differentially. On the other hand, they suggest that H₂O₂ could be an important mediator of etoposide and TNF-α-dependent cell death since these inducers trigger similar phenotypes.

  15. Prognostic significance of bcl-2 protein expression in aggressive non-Hodgkin's lymphoma. Groupe d'Etude des Lymphomes de l'Adulte (GELA).

    PubMed

    Hermine, O; Haioun, C; Lepage, E; d'Agay, M F; Briere, J; Lavignac, C; Fillet, G; Salles, G; Marolleau, J P; Diebold, J; Reyas, F; Gaulard, P

    1996-01-01

    Little is known about the expression of bcl-2 protein in intermediate and high grade non-Hodgkin's lymphoma (NHL) and its clinical and prognostic significance. We performed immunohistochemical analysis of bcl-2 expression in tumoral tissue sections of 348 patients with high or intermediate grade NHL. These patients were uniformly treated with adriamycin, cyclophosphamide, vindesine, bleomycin, and prednisone (ACVBP) in the induction phase of the LNH87 protocol. Fifty eight cases were excluded due to inadequate staining. Of the 290 remaining patients, 131 (45%) disclosed homogeneous positivity (high bcl-2 expression) in virtually all tumor cells, whereas 65 (23%) were negative and 94 (32%) exhibited intermediate staining. High bcl-2 expression was more frequent in B-cell NHL (109 of 214, 51%) than in T-cell NHL (6 of 35, 17%) (P = .0004), and was heterogeneously distributed among the different histological subtypes. Further analysis was performed on the 151 patients with diffuse large B-cell lymphoma (centroblastic and immunoblastic) to assess the clinical significance and potential prognostic value of bcl-2 expression in the most frequent and homogeneous immunohistological subgroup. High bcl-2 expression, found in 44% of these patients (67 of 151), was more frequently associated with III-IV stage disease (P = .002). Reduced disease-free survival (DFS) (P < .01) and overall survival (P < .05) were demonstrated in the patients with high bcl-2 expression. Indeed, the 3-year estimates of DFS and overall survival were 60% and 61%, respectively (high bcl-2 expression) versus 82% and 78%, respectively (negative/intermediate bcl-2 expression). A multivariate regression analysis confirmed the independent effect of bcl-2 protein expression on DFS. Thus bcl-2 protein expression, as demonstrated in routinely paraffin-embedded tissue, appears to be predictive of poor DFS, in agreement with the role of bcl-2 in chemotherapy-induced apoptosis. It might be considered as a new

  16. Relationship between reduced BCL-2 expression in circulating mononuclear cells and early nephropathy in type 1 diabetes.

    PubMed

    Cipollone, F; Chiarelli, F; Iezzi, A; Fazia, M L; Cuccurullo, C; Pini, B; De Cesare, D; Torello, M; Tumini, S; Cuccurullo, F; Mezzetti, A

    2005-01-01

    Microalbuminuria is the earliest clinical evidence of diabetic nephropathy, but the mechanisms linking hyperglycemia and kidney complications are not clear. The aim of this study was to evaluate whether enhanced oxidative stress in patients with microalbuminuria can contribute to diabetic nephropathy development through downregulation of the antiapoptotic gene Bcl-2 that promotes in turn a pro-inflammatory status. We studied 30 patients with type 1 diabetes (15 with and 15 without microalbuminuria) compared to 15 matched healthy controls. Plasma oxidant status, and expression of Bcl-2, activated NF-kB, inducible Nitric Oxide synthase (iNOS), and monocyte chemoattractant protein (MCP)-1 in circulating monocytes were evaluated at baseline and after 8-week oral vitamin E treatment (600 mg b.i.d.). Bcl-2 expression was significantly reduced in microalbuminuric diabetic patients as a consequence of increased oxidant burden secondary to persistent hyperglycemia. Bcl-2 down-regulation was associated with enhanced expression of NF-kB, iNOS and MCP-1, and showed a strong correlation with the albumin excretion rate. Low Bcl-2 expression and high inflammatory status were normalized by vitamin E both in vivo and in vitro. Our study showed that Bcl-2 down-regulation in diabetic patients with poor glycemic control results in the activation of the NF-kB pathway leading to the development of nephropathy. Vitamin E might provide a novel form of therapy for prevention of nephropathy in diabetic patients in which an acceptable glycemic control is difficult to achieve despite insulin therapy.

  17. Reflection: The Early Career Surgeon-Scientist's Pathway to Independence.

    PubMed

    Smith, Stephanie Shintani

    2016-01-01

    The surgeon-scientist offers a unique perspective as one who can arguably best comprehend clinical needs, identify areas ripe for research, and translate discoveries from bench to bedside. However, the long transition from postdoc to independent investigator can prove to be quite challenging. Surgeons have long been described as having results-oriented personalities, and so the long road to independence can be fraught with frustration at times. It requires humility in seeking scientific direction and mentorship, institutional support, and ultimately extramural funding. This reflection piece examines some hallmark steps along the pathway to independence for one otolaryngology-head and neck surgeon-scientist in her early academic career.

  18. Bcl-2 Conformational Change as an Indicator of Chemotherapy Response

    DTIC Science & Technology

    2005-09-01

    conformational Control change in MCF-7 breast cancer cells. Immunostaining of apoptotic Bcl-2. H460 - cells were treated with or Paclitaxel without...NuBCPs target mitochondria. GFP-NuBCP and mitochondria-targeted Red Fluorescent Protein (RFP-mito) were transfected into H460 cells for 16 h. Confocal...microscopy analysis showed that in H460 cells GFP-NuBCP colocalized extensively with that of RFP-Mito, a red fluorescence protein (RFP) fused with a

  19. Patients with diffuse large B-cell lymphoma of germinal center origin with BCL2 translocations have poor outcome, irrespective of MYC status: a report from an International DLBCL rituximab-CHOP Consortium Program Study.

    PubMed

    Visco, Carlo; Tzankov, Alexander; Xu-Monette, Zijun Y; Miranda, Roberto N; Tai, Yu Chuan; Li, Yan; Liu, Wei-min; d'Amore, Emanuele S G; Li, Yong; Montes-Moreno, Santiago; Dybkær, Karen; Chiu, April; Orazi, Attilio; Zu, Youli; Bhagat, Govind; Wang, Huan-You; Dunphy, Cherie H; His, Eric D; Zhao, X Frank; Choi, William W L; Zhao, Xiaoying; van Krieken, J Han; Huang, Qin; Ai, Weiyun; O'Neill, Stacey; Ponzoni, Maurilio; Ferreri, Andres J M; Kahl, Brad S; Winter, Jane N; Go, Ronald S; Dirnhofer, Stephan; Piris, Miguel A; Møller, Michael B; Wu, Lin; Medeiros, L Jeffrey; Young, Ken H

    2013-02-01

    Diffuse large B-cell lymphoma can be classified by gene expression profiling into germinal center and activated B-cell subtypes with different prognoses after rituximab-CHOP. The importance of previously recognized prognostic markers, such as Bcl-2 protein expression and BCL2 gene abnormalities, has been questioned in the new therapeutic era. We analyzed Bcl-2 protein expression, and BCL2 and MYC gene abnormalities by interphase fluorescence in situ hybridization in 327 patients with de novo disease treated with rituximab-CHOP. Isolated BCL2 and MYC rearrangements were not predictive of outcome in our patients as a whole, but only in those with the germinal center subtype of lymphoma. The prognostic relevance of isolated MYC rearrangements was weaker than that of BCL2 isolated translocations, but was probably limited by the rarity of the rearrangements. Seven of eight patients with double hit lymphoma had the germinal center subtype with poor outcome. The germinal center subtype patients with isolated BCL2 translocations had significantly worse outcome than the patients without BCL2 rearrangements (P=0.0002), and their outcome was similar to that of patients with the activated B-cell subtype (P=0.30), but not as bad as the outcome of patients with double hit lymphoma (P<0.0001). Bcl-2 protein overexpression was associated with inferior outcome in patients with germinal center subtype lymphoma, but multivariate analysis showed that this was dependent on BCL2 translocations. The gene expression profiling of patients with BCL2 rearrangements was unique, showing activation of pathways that were silent in the negative counterpart. BCL2 translocated germinal center subtype patients have worse prognosis after rituximab-CHOP, irrespective of MYC status, but the presence of combined gene breaks significantly overcomes the prognostic relevance of isolated lesions.

  20. Mesothelin regulates growth and apoptosis in pancreatic cancer cells through p53-dependent and -independent signal pathway.

    PubMed

    Zheng, Chunning; Jia, Wei; Tang, Yong; Zhao, HuiLiang; Jiang, Yingsheng; Sun, Shaochuan

    2012-10-03

    Mesothelin, a secreted protein, is overexpressed in some cancers, including pancreatic cancer. Rescent studies have shown that overexpression of mesothelin significantly increased tumor cell proliferation, and downregulation of mesothelin inhibited cell proliferation in pancreatic cancer cells, but its exact function and mechanism remains unclear. The aim of the present study was to evaluate the effects of mesothelin on proliferation and apoptosis in pancreatic cancer cells with different p53 status and to explore its signal pathway. Mesothelin levels were detected by western blot and RT-PCR assay in human pancreatic cancer AsPC-1, HPAC and Capan-2, Capan-1 and MIA PaCa-2 cell lines. Mesothelin was slienced by shRNA in AsPC-1, Capan-2 and Capan-1 cells with rich mesothelin level, and mesothelin was overexpressed in the HPAC and Capan-2 cells with less mesothelin level. We observed that in the AsPC-1 and Capan-1cells with mt-p53, and Capan-2 cells with wt-p53, shRNA mediated sliencing of the mesothelin significantly increased PUMA and Bax expression and caspase-3 activity, and decreased bcl-2 expression, followed by the reduced proliferation and colony forming capability and increased cell apoptosis. When PUMA was slienced by siRNA in the stable mesothelin shRNA transfected cells, proliferative capability was significantly increased, and apoptosis was decreased. However, in the Capan-2 cells with wt-p53, suppression of the mesothelin significantly increased wt-p53 levels. When p53 was blocked by siRNA in the stable mesothelin shRNA transfected Capan-2 cells, PUMA was inhibited, followed by increased proliferative capability and decreased cell apoptosis. In the HPAC and Capan-2 cells with wt-p53 and in the MIA PaCa-2 cells with mt-p53, overexpression of the mesothelin significantly decreased bax levels and increased bcl-2 levels, followed by increased proliferative and colony forming capability. Furthermore, mesothelin-shRNA-transfected cells exhibited a reduced rate

  1. Statins, Bcl-2, and apoptosis: cell death or cell protection?

    PubMed

    Wood, W Gibson; Igbavboa, Urule; Muller, Walter E; Eckert, Gunter P

    2013-10-01

    Statins have proven their effectiveness in the treatment of cardiovascular disease. This class of drugs has also attracted attention as a potential treatment for dissimilar diseases such as certain types of cancers and neurodegenerative diseases. What appears to be a contradiction is that, in the case of cancer, it has been suggested that statins increase apoptosis and alter levels of Bcl-2 family members (e.g., reduce Bcl-2 and increase Bax), whereas studies mainly using noncancerous cells report opposite effects. This review examined studies reporting on the effects of statins on Bcl-2 family members, apoptosis, cell death, and cell protection. Much, but not all, of the evidence supporting the pro-apoptotic effects of statins is based on data in cancer cell lines and the use of relatively high drug concentrations. Studies indicating an anti-apoptotic effect of statins are fewer in number and generally used much lower drug concentrations and normal cells. Those conclusions are not definitive, and certainly, there is a need for additional research to determine if statin repositioning is justified for noncardiovascular diseases.

  2. Overexpression of MYC and BCL2 Predicts Poor Prognosis in Patients with Extranodal NK/T-cell Lymphoma, Nasal Type

    PubMed Central

    Wang, Jing-hua; Bi, Xi-wen; Li, Peng-fei; Xia, Zhong-jun; Huang, Hui-qiang; Jiang, Wen-qi; Zhang, Yu-jing; Wang, Liang

    2017-01-01

    Background: Recently double-hit lymphoma or double protein expressor lymphoma has been identified as a distinct group of diffuse large B cell lymphoma with poor prognosis. However, the expression status, clinical and prognostic effect of combined overexpression of MYC and BCL2 in extranodal NK/T-cell lymphoma, nasal type (ENKTL) are not known. Materials and methods: Paraffin-embedded lymphoma samples from 53 patients with newly diagnosed ENKTL were studied using immunohistochemistry for MYC and BCL2, and fluorescent in situ hybridization (FISH) for MYC and BCL2 were done on 5 tissue sections with highest percentages of both MYC and BCL2 positive lymphoma cells. Results: The median percentage of MYC-positive lymphoma cells and BCL2-positive lymphoma cells were 20% (range, 5%-45%) and 70% (10%-95%), respectively. Using median scores as cutoffs, we assigned each patient an IHC double-hit score (DHS) that ranged from 0 to 2. Using this DHS, 15 patients (28.3%) had a DHS of 0, 24 patients (45.3%) had a DHS of 1, and the remaining 14 patients (26.4%) had a DHS of 2. FISH analysis was performed on 5 tissue sections with DHS of 2, and none of them had MYC or BCL2 rearrangement. The DHS was not associated with patients' age, gender, disease stage, LDH level, B symptoms, performance status, or local tumor invasiveness. However, patients with tumor localized in extranasal sites seemed to have higher expression of BCL2 and higher DHS than nasal lesions (p=0.014 and 0.042, respectively). In univariate survival analysis, either high expression of MYC or BCL2 was significantly correlated with inferior PFS and OS (p<0.05). According to the DHS, patients with ENKTL could be divided into three significantly different risk groups for PFS and OS (3-year PFS rate for DHS of 0, 1, and 2 was 60%, 41%, and 21%, respectively, p=0.008; 3-year OS rate for DHS of 0, 1, and 2 was 79%, 49%, and 33%, respectively, p=0.015). In multivariate survival analysis, it was found that DHS was an

  3. Caspase-Dependent and Caspase-Independent Pathways Are Involved in Cadmium-Induced Apoptosis in Primary Rat Proximal Tubular Cell Culture

    PubMed Central

    Long, Mengfei; Bian, Jianchun; Liu, Xuezhong; Gu, Jianhong; Yuan, Yan; Song, Ruilong; Wang, Yi; Zhu, Jiaqiao; Liu, Zongping

    2016-01-01

    We designed this study to investigate whether cadmium induces caspase-independent apoptosis and to investigate the relationship between the caspase-dependent and caspase-independent apoptotic pathways. Cadmium (1.25–2.5 μM) induced oxidative stress in rat proximal tubular (rPT) cells, as seen in the reactive oxygen species levels; N-acetylcysteine prevented this. Cyclosporin A (CsA) prevented mitochondrial permeability transition pore opening and apoptosis; there was mitochondrial ultrastructural disruption, mitochondrial cytochrome c (cyt c) translocation to the cytoplasm, and subsequent caspase-9 and caspase-3 activation. Z-VAD-FMK prevented caspase-3 activation and apoptosis and decreased BNIP-3 (Bcl-2/adenovirus E1B 19-kDa interacting protein 3) expression levels and apoptosis-inducing factor/endonuclease G (AIF/Endo G) translocation. Simultaneously, cadmium induced prominent BNIP-3 expression in the mitochondria and cytoplasmic AIF/Endo G translocation to the nucleus. BNIP-3 silencing significantly prevented AIF and Endo G translocation and decreased the apoptosis rate, cyt c release, and caspase-9 and caspase-3 activation. These results suggest that BNIP-3 is involved in the caspase-independent apoptotic pathway and is located upstream of AIF/Endo G; both the caspase-dependent and caspase-independent pathways are involved in cadmium-induced rPT cell apoptosis and act synergistically. PMID:27861627

  4. Viral Bcl-2 Encoded by the Kaposi's Sarcoma-Associated Herpesvirus Is Vital for Virus Reactivation

    PubMed Central

    Gelgor, Anastasia; Kalt, Inna; Bergson, Shir; Brulois, Kevin F.; Jung, Jae U.

    2015-01-01

    ABSTRACT The Kaposi's sarcoma-associated herpesvirus (KSHV) open reading frame 16 (orf16) encodes a viral Bcl-2 (vBcl-2) protein which shares sequence and functional homology with the Bcl-2 family. Like its cellular homologs, vBcl-2 protects various cell types from apoptosis and can also negatively regulate autophagy. vBcl-2 is transcribed during lytic infection; however, its exact function has not been determined to date. By using bacterial artificial chromosome 16 (BAC16) clone carrying the full-length KSHV genome, we have generated recombinant KSHV mutants that fail to express vBcl-2 or express mCherry-tagged vBcl-2. We show that the vBcl-2 protein is expressed at relatively low levels during lytic induction and that a lack of vBcl-2 largely reduces the efficiency of KSHV reactivation in terms of lytic gene expression, viral DNA replication, and production of infectious particles. In contrast, the establishment of latency was not affected by the absence of vBcl-2. Our findings suggest an important role for vBcl-2 during initial phases of lytic reactivation and/or during subsequent viral propagation. Given the known functions of vBcl-2 in regulating apoptosis and autophagy, which involve its direct interaction with cellular proteins and thus require high levels of protein expression, it appears that vBcl-2 may have additional regulatory functions that do not depend on high levels of protein expression. IMPORTANCE The present study shows for the first time the expression of endogenous vBcl-2 protein in KSHV-infected cell lines and demonstrates the importance of vBcl-2 during the initial phases of lytic reactivation and/or during its subsequent propagation. It is suggested that vBcl-2 has additional regulatory functions beyond apoptosis and autophagy repression that do not depend on high levels of protein expression. PMID:25740992

  5. PK11195 inhibits mitophagy targeting the F1Fo-ATPsynthase in Bcl-2 knock-down cells.

    PubMed

    Seneviratne, M S D; Faccenda, D; De Biase, V; Campanella, M

    2012-05-01

    The pharmacological agent 1-(2-Chlorophenyl-N-methylpropyl)-3-isoquinolinecarboxamide (PK11195) is the prototypical ligand of the 18-kDa Translocator Protein (TSPO) but at μM concentrations deactivates the oncoprotein Bcl-2 increasing the efficiency of chemotherapeutic agents and promoting the Ca2+-dependent macro-autophagy (or autophagy). In this paper, we report that PK11195, in HeLa cells, modifies the mitochondria-targeted type of autophagy--hereafter referred to as mitophagy--and the associated resizing of the mitochondrial network but does so exclusively in absence of the oncoprotein Bcl-2 (Bcl-2 Kd cells). This is consequence of a "side" targeting of the mitochondrial F1Fo-ATPsynthase enzyme, since identical outcome is mimicked by the antibiotic Oligomycin, of which PK11195 matches the effect on: i) mitochondrial membrane potential (ΔΨm), ii) ATP homeostasis and iii) Reactive Oxygen Species (ROS) generation. Taken together, these data highlight a novel TSPO-independent biological effect for PK11195 and provide evidences for a hitherto uncovered Bcl-2-dependent role of the F1Fo-ATPsynthase in mitochondrial quality control.

  6. Regulation of mitochondrial ceramide distribution by members of the BCL-2 family[S

    PubMed Central

    Zhang, Tejia; Barclay, Lauren; Walensky, Loren D.; Saghatelian, Alan

    2015-01-01

    Apoptosis is an intricately regulated cellular process that proceeds through different cell type- and signal-dependent pathways. In the mitochondrial apoptotic program, mitochondrial outer membrane permeabilization by BCL-2 proteins leads to the release of apoptogenic factors, caspase activation, and cell death. In addition to protein components of the mitochondrial apoptotic machinery, an interesting role for lipids and lipid metabolism in BCL-2 family-regulated apoptosis is also emerging. We used a comparative lipidomics approach to uncover alterations in lipid profile in the absence of the proapoptotic proteins BAX and BAK in mouse embryonic fibroblasts (MEFs). We detected over 1,000 ions in these experiments and found changes in an ion with an m/z of 534.49. Structural elucidation of this ion through tandem mass spectrometry revealed that this molecule is a ceramide with a 16-carbon N-acyl chain and sphingadiene backbone (d18:2/16:0 ceramide). Targeted LC/MS analysis revealed elevated levels of additional sphingadiene-containing ceramides (d18:2-Cers) in BAX, BAK-double knockout MEFs. Elevated d18:2-Cers are also found in immortalized baby mouse kidney epithelial cells lacking BAX and BAK. These results support the existence of a distinct biochemical pathway for regulating ceramides with different backbone structures and suggest that sphingadiene-containing ceramides may have functions that are distinct from the more common sphingosine-containing species. PMID:26059977

  7. Chemical parsing: Dissecting cell dependencies with a toolkit of selective BCL-2 family inhibitors.

    PubMed

    Leverson, Joel D

    2016-01-01

    The BCL-2/BCL-XL inhibitor navitoclax has shown promise for the treatment of cancer but on-target toxicities have limited its utility. Recently, the generation of selective BCL-2 family inhibitors has enabled a careful dissection of BCL-2 biology, and early work indicates that these molecules have improved therapeutic profiles for the treatment of cancer.

  8. Combining CAR T cells and the Bcl-2 family apoptosis inhibitor ABT-737 for treating B-cell malignancy.

    PubMed

    Karlsson, H; Karlsson, S C H; Lindqvist, A C; Fransson, M; Paul-Wetterberg, G; Nilsson, B; Essand, M; Nilsson, K; Frisk, P; Jernberg-Wiklund, H; Loskog, A; Loskog, S I A

    2013-07-01

    B-cell malignancies upregulate the B-cell lymphoma 2 (Bcl-2) family inhibitors of the intrinsic apoptosis pathway, making them therapy resistant. However, small-molecule inhibitors of Bcl-2 family members such as ABT-737 restore a functional apoptosis pathway in cancer cells, and its oral analog ABT-263 (Navitoclax) has entered clinical trials. Gene engineered chimeric antigen receptor (CAR) T cells also show promise in B-cell malignancy, and as they induce apoptosis via the extrinsic pathway, we hypothesized that small-molecule inhibitors of the Bcl-2 family may potentiate the efficacy of CAR T cells by engaging both apoptosis pathways. CAR T cells targeting CD19 were generated from healthy donors as well as from pre-B-ALL (precursor-B acute lymphoblastic leukemia) patients and tested together with ABT-737 to evaluate apoptosis induction in five B-cell tumor cell lines. The CAR T cells were effective even if the cell lines exhibited different apoptosis resistance profiles, as shown by analyzing the expression of apoptosis inhibitors by PCR and western blot. When combining T-cell and ABT-737 therapy simultaneously, or with ABT-737 as a presensitizer, tumor cell apoptosis was significantly increased. In conclusion, the apoptosis inducer ABT-737 enhanced the efficacy of CAR T cells and could be an interesting drug candidate to potentiate T-cell therapy.

  9. Telomerase activity, estrogen receptors (α, β), Bcl-2 expression in human breast cancer and treatment response

    PubMed Central

    Murillo-Ortiz, Blanca; Astudillo-De la Vega, Horacio; Castillo-Medina, Sebastian; Malacara, JM; Benitez-Bribiesca, Luis

    2006-01-01

    Background The mechanism for maintaining telomere integrity is controlled by telomerase, a ribonucleoprotein enzyme that specifically restores telomere sequences, lost during replication by means of an intrinsic RNA component as a template for polymerization. Among the telomerase subunits, hTERT (human telomerase reverse transcriptase) is expressed concomitantly with the activation of telomerase. The role of estrogens and their receptors in the transcriptional regulation of hTERT has been demonstrated. The current study determines the possible association between telomerase activity, the expression of both molecular forms of estrogen receptor (ERα and ERβ) and the protein bcl-2, and their relative associations with clinical parameters. Methods Tissue samples from 44 patients with breast cancer were used to assess telomerase activity using the TRAP method and the expression of ERα, ERβ and bcl-2 by means of immunocytochemical techniques. Results Telomerase activity was detected in 59% of the 44 breast tumors examined. Telomerase activity ranged from 0 to 49.93 units of total product generated (TPG). A correlation was found between telomerase activity and differentiation grade (p = 0.03). The only significant independent marker of response to treatment was clinical stage. We found differences between the frequency of expression of ERα (88%) and ERβ (36%) (p = 0.007); bcl-2 was expressed in 79.5% of invasive breast carcinomas. We also found a significant correlation between low levels of telomerase activity and a lack of ERβ expression (p = 0.03). Conclusion Lower telomerase activity was found among tumors that did not express estrogen receptor beta. This is the first published study demonstrating that the absence of expression of ERβ is associated with low levels of telomerase activity. PMID:16911782

  10. Leishmania donovani-Induced Increase in Macrophage Bcl-2 Favors Parasite Survival

    PubMed Central

    Pandey, Rajeev Kumar; Mehrotra, Sanjana; Sharma, Smriti; Gudde, Ramachandra Subbaraya; Sundar, Shyam; Shaha, Chandrima

    2016-01-01

    Members of the Bcl-2 family are major regulators of apoptosis in mammalian cells, and hence infection-induced perturbations in their expression could result into elimination of the parasites or creation of a niche favoring survival. In this investigation, we uncover a novel role of host Bcl-2 in sustaining Leishmania donovani infection. A rapid twofold increase in Bcl-2 expression occurred in response to parasite challenge. Downregulation of post infection Bcl-2 increase using siRNA or functional inhibition using Bcl-2 small molecule inhibitors interfered with intracellular parasite survival confirming the necessity of elevated Bcl-2 during infection. An increased nitric oxide (NO) response and reduced parasitic burden was observed upon Bcl-2 inhibition, where restitution of the NO response accounted for parasite mortality. Mechanistic insights revealed a major role of elevated Th2 cytokine IL-13 in parasite-induced Bcl-2 expression via the transcription factor STAT-3, where blocking at the level of IL-13 receptor or downstream kinase JAK-2 dampened Bcl-2 induction. Increase in Bcl-2 was orchestrated through Toll like receptor (TLR)-2-MEK-ERK signaling, and changes in TLR-2 levels affected parasite uptake. In a mouse model of visceral leishmaniasis (VL), Bcl-2 inhibitors partially restored the antimicrobial NO response by at least a twofold increase that resulted in significantly reduced parasite burden. Interestingly, monocytes derived from the peripheral blood of six out of nine human VL subjects demonstrated Bcl-2 expression at significantly higher levels, and sera from these patients showed only marginally quantifiable nitrites. Collectively, our study for the first time reveals a pro-parasitic role of host Bcl-2 and the capacity of host-derived IL-13 to modulate NO levels during infection via Bcl-2. Here, we propose Bcl-2 inhibition as a possible therapeutic intervention for VL. PMID:27826299

  11. MicroRNA-744 inhibited cervical cancer growth and progression through apoptosis induction by regulating Bcl-2.

    PubMed

    Chen, Xiao-Fang; Liu, Yun

    2016-07-01

    Growing evidence suggests that microRNA plays an essential role in the development and metastasis of many tumor progressions, including cervical cancer. Aberrant miR-744 expression has been indicated in many growth of tumor, the mechanism of miR-744 inhibits both the proliferation and metastatic ability for cervical cancer remains unclear. Accumulating evidences reported that Bcl-2 signal pathway plays an important role in the cellular process, such as apoptosis, cell growth and proliferation. The goal of this study was to identify miR-744 that could inhibit the growth, migration, invasion, proliferation and metastasis of gastric cancer through targeting Bcl-2 expression. Real-time PCR (RT-qPCR) was used to quantify miR-744 expression in vitro and vivo experiments. The biological functions of miR-744 were determined via cell proliferation. Our study indicated that miR-744 targeted on Bcl-2, which leads to the inactivation of apoptosis signaling and the cell proliferation of cervical cancer cells, ameliorating cervical cancer growth and progression. In addition, both up-regulation of miR-744 and down-regulation of Bcl-2 could stimulate Caspase-3 expression, promoting apoptosis of cervical cancer cells. Therefore, our research revealed the mechanistic links between miR-744 and Bcl-2 in the pathogenesis of cervical cancer through modulation of Caspase-3, leading to the inhibition of cervical cancer cell growth. And targeting miR-744 could be served as a novel strategy for future cervical cancer therapy clinically.

  12. The involvement of Bcl-2 family proteins in AKT-regulated cell survival in cisplatin resistant epithelial ovarian cancer

    PubMed Central

    Dai, Yan; Jin, Shiguang; Li, Xueping; Wang, Daxin

    2017-01-01

    Many studies involving patients with cisplatin-resistant ovarian cancer have shown that AKT activation leads to inhibition of apoptosis. The aim of this study was to examine the potential involvement of the Bcl-2 family proteins in AKT-regulated cell survival in response to cisplatin treatment. Cisplatin-sensitive (PEO1) and cisplatin-resistant (PEO4) cells were taken from ascites of patients with ovarian cancer before cisplatin treatment and after development of chemoresistance. It was found that cisplatin treatment activated the AKT signaling pathway and promoted cell proliferation in cisplatin-resistant EOC cells. When AKT was transfected into nucleus of cisplatin-resistant ovarian cancer cells, DNA-PK was phosphorylated at S473. The activated AKT (pAKT-S473) in these cells inhibited the death signal induced by cisplatin thereby inhibiting cisplatin-mediated apoptosis. Results from this study showed that the combination of cisplatin, DNA-PK inhibitor NU7441, and AKT inhibitor TCN can overcome drug resistance, increase apoptosis, and re-sensitize PEO4 cells to cisplatin treatment. A decrease in apoptotic activity was seen in PEO4 cells when Bad was downregulated by siRNA, which indicated that Bad promotes apoptosis in PEO4 cells. Use of the Bcl-2 inhibitor ABT-737 showed that ABT-737 binds to Bcl-2 but not Mcl-1 and releases Bax/Bak which leads to cell apoptosis. The combination of ABT-737 and cisplatin leads to a significant increase in the death of PEO1 and PEO4 cells. All together, these results indicate that Bcl-2 family proteins are regulators of drug resistance. The combination of cisplatin and Bcl-2 family protein inhibitor could be a strategy for the treatment of cisplatin-resistant ovarian cancer. PMID:27935869

  13. ATP promotes cell survival via regulation of cytosolic [Ca2+] and Bcl-2/Bax ratio in lung cancer cells.

    PubMed

    Song, Shanshan; Jacobson, Krista N; McDermott, Kimberly M; Reddy, Sekhar P; Cress, Anne E; Tang, Haiyang; Dudek, Steven M; Black, Stephen M; Garcia, Joe G N; Makino, Ayako; Yuan, Jason X-J

    2016-01-15

    Adenosine triphosphate (ATP) is a ubiquitous extracellular messenger elevated in the tumor microenvironment. ATP regulates cell functions by acting on purinergic receptors (P2X and P2Y) and activating a series of intracellular signaling pathways. We examined ATP-induced Ca(2+) signaling and its effects on antiapoptotic (Bcl-2) and proapoptotic (Bax) proteins in normal human airway epithelial cells and lung cancer cells. Lung cancer cells exhibited two phases (transient and plateau phases) of increase in cytosolic [Ca(2+)] ([Ca(2+)]cyt) caused by ATP, while only the transient phase was observed in normal cells. Removal of extracellular Ca(2+) eliminated the plateau phase increase of [Ca(2+)]cyt in lung cancer cells, indicating that the plateau phase of [Ca(2+)]cyt increase is due to Ca(2+) influx. The distribution of P2X (P2X1-7) and P2Y (P2Y1, P2Y2, P2Y4, P2Y6, P2Y11) receptors was different between lung cancer cells and normal cells. Proapoptotic P2X7 was nearly undetectable in lung cancer cells, which may explain why lung cancer cells showed decreased cytotoxicity when treated with high concentration of ATP. The Bcl-2/Bax ratio was increased in lung cancer cells following treatment with ATP; however, the antiapoptotic protein Bcl-2 demonstrated more sensitivity to ATP than proapoptotic protein Bax. Decreasing extracellular Ca(2+) or chelating intracellular Ca(2+) with BAPTA-AM significantly inhibited ATP-induced increase in Bcl-2/Bax ratio, indicating that a rise in [Ca(2+)]cyt through Ca(2+) influx is the critical mediator for ATP-mediated increase in Bcl-2/Bax ratio. Therefore, despite high ATP levels in the tumor microenvironment, which would induce cell apoptosis in normal cells, the decreased P2X7 and elevated Bcl-2/Bax ratio in lung cancer cells may enable tumor cells to survive. Increasing the Bcl-2/Bax ratio by exposure to high extracellular ATP may, therefore, be an important selective pressure promoting transformation and cancer progression.

  14. Expression Profile of BCL-2, BCL-XL, and MCL-1 Predicts Pharmacological Response to the BCL-2 Selective Antagonist Venetoclax in Multiple Myeloma Models.

    PubMed

    Punnoose, Elizabeth A; Leverson, Joel D; Peale, Franklin; Boghaert, Erwin R; Belmont, Lisa D; Tan, Nguyen; Young, Amy; Mitten, Michael; Ingalla, Ellen; Darbonne, Walter C; Oleksijew, Anatol; Tapang, Paul; Yue, Peng; Oeh, Jason; Lee, Leslie; Maiga, Sophie; Fairbrother, Wayne J; Amiot, Martine; Souers, Andrew J; Sampath, Deepak

    2016-05-01

    BCL-2 family proteins dictate survival of human multiple myeloma cells, making them attractive drug targets. Indeed, multiple myeloma cells are sensitive to antagonists that selectively target prosurvival proteins such as BCL-2/BCL-XL (ABT-737 and ABT-263/navitoclax) or BCL-2 only (ABT-199/GDC-0199/venetoclax). Resistance to these three drugs is mediated by expression of MCL-1. However, given the selectivity profile of venetoclax it is unclear whether coexpression of BCL-XL also affects antitumor responses to venetoclax in multiple myeloma. In multiple myeloma cell lines (n = 21), BCL-2 is expressed but sensitivity to venetoclax correlated with high BCL-2 and low BCL-XL or MCL-1 expression. Multiple myeloma cells that coexpress BCL-2 and BCL-XL were resistant to venetoclax but sensitive to a BCL-XL-selective inhibitor (A-1155463). Multiple myeloma xenograft models that coexpressed BCL-XL or MCL-1 with BCL-2 were also resistant to venetoclax. Resistance to venetoclax was mitigated by cotreatment with bortezomib in xenografts that coexpressed BCL-2 and MCL-1 due to upregulation of NOXA, a proapoptotic factor that neutralizes MCL-1. In contrast, xenografts that expressed BCL-XL, MCL-1, and BCL-2 were more sensitive to the combination of bortezomib with a BCL-XL selective inhibitor (A-1331852) but not with venetoclax cotreatment when compared with monotherapies. IHC of multiple myeloma patient bone marrow biopsies and aspirates (n = 95) revealed high levels of BCL-2 and BCL-XL in 62% and 43% of evaluable samples, respectively, while 34% were characterized as BCL-2(High)/BCL-XL (Low) In addition to MCL-1, our data suggest that BCL-XL may also be a potential resistance factor to venetoclax monotherapy and in combination with bortezomib. Mol Cancer Ther; 15(5); 1132-44. ©2016 AACR.

  15. Platelet production proceeds independently of the intrinsic and extrinsic apoptosis pathways.

    PubMed

    Josefsson, Emma C; Burnett, Deborah L; Lebois, Marion; Debrincat, Marlyse A; White, Michael J; Henley, Katya J; Lane, Rachael M; Moujalled, Diane; Preston, Simon P; O'Reilly, Lorraine A; Pellegrini, Marc; Metcalf, Donald; Strasser, Andreas; Kile, Benjamin T

    2014-03-17

    BH3 mimetic drugs that target BCL-2 family pro-survival proteins to induce tumour cell apoptosis represent a new era in cancer therapy. Clinical trials of navitoclax (ABT-263, which targets BCL-2, BCL-XL and BCL-W) have shown great promise, but encountered dose-limiting thrombocytopenia. Recent work has demonstrated that this is due to the inhibition of BCL-XL, which is essential for platelet survival. These findings raise new questions about the established model of platelet shedding by megakaryocytes, which is thought to be an apoptotic process. Here we generate mice with megakaryocyte-specific deletions of the essential mediators of extrinsic (Caspase-8) and intrinsic (BAK/BAX) apoptosis. We show that megakaryocytes possess a Fas ligand-inducible extrinsic apoptosis pathway. However, Fas activation does not stimulate platelet production, rather, it triggers Caspase-8-mediated killing. Combined loss of Caspase-8/BAK/BAX does not impair thrombopoiesis, but can protect megakaryocytes from death in mice infected with lymphocytic choriomeningitis virus. Thus, apoptosis is dispensable for platelet biogenesis.

  16. Impact of dual expression of MYC and BCL2 by immunohistochemistry on the risk of CNS relapse in DLBCL.

    PubMed

    Savage, Kerry J; Slack, Graham W; Mottok, Anja; Sehn, Laurie H; Villa, Diego; Kansara, Roopesh; Kridel, Robert; Steidl, Christian; Ennishi, Daisuke; Tan, King L; Ben-Neriah, Susana; Johnson, Nathalie A; Connors, Joseph M; Farinha, Pedro; Scott, David W; Gascoyne, Randy D

    2016-05-05

    Dual expression of MYC and BCL2 by immunohistochemistry (IHC) is associated with poor outcome in diffuse large B-cell lymphoma (DLBCL). Dual translocation of MYC and BCL2, so-called "double-hit lymphoma," has been associated with a high risk of central nervous system (CNS) relapse; however, the impact of dual expression of MYC and BCL2 (dual expressers) on the risk of CNS relapse remains unknown. Pretreatment formalin-fixed paraffin-embedded DLBCL biopsies derived from patients subsequently treated with rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) were assembled on tissue microarrays from 2 studies and were evaluated for expression of MYC and BCL2 by IHC. In addition, cell of origin was determined by IHC and the Lymph2Cx gene expression assay in a subset of patients. We identified 428 patients who met the inclusion criteria. By the recently described CNS risk score (CNS-International Prognostic Index [CNS-IPI]), 34% were low risk (0 to 1), 45% were intermediate risk (2 to 3), and 21% were high risk (4 or greater). With a median follow-up of 6.8 years, the risk of CNS relapse was higher in dual expressers compared with non-dual expressers (2-year risk, 9.7% vs 2.2%; P = .001). Patients with activated B-cell or non-germinal center B-cell type DLBCL also had an increased risk of CNS relapse. However, in multivariate analysis, only dual expresser status and CNS-IPI were associated with CNS relapse. Dual expresser MYC(+) BCL2(+) DLBCL defines a group at high risk of CNS relapse, independent of CNS-IPI score and cell of origin. Dual expresser status may help to identify a high-risk group who should undergo CNS-directed evaluation and consideration of prophylactic strategies.

  17. The selective Bcl-2 inhibitor venetoclax, a BH3 mimetic, does not dysregulate intracellular Ca(2+) signaling.

    PubMed

    Vervloessem, Tamara; Ivanova, Hristina; Luyten, Tomas; Parys, Jan B; Bultynck, Geert

    2016-11-30

    Anti-apoptotic B cell-lymphoma-2 (Bcl-2) proteins are emerging as therapeutic targets in a variety of cancers for precision medicines, like the BH3-mimetic drug venetoclax (ABT-199), which antagonizes the hydrophobic cleft of Bcl-2. However, the impact of venetoclax on intracellular Ca(2+) homeostasis and dynamics in cell systems has not been characterized in detail. Here, we show that venetoclax did not affect Ca(2+)-transport systems from the endoplasmic reticulum (ER) in permeabilized cell systems. Venetoclax (1μM) did neither trigger Ca(2+) release by itself nor affect agonist-induced Ca(2+) release in a variety of intact cell models. Among the different cell types, we also studied two Bcl-2-dependent cancer cell models with a varying sensitivity towards venetoclax, namely SU-DHL-4 and OCI-LY-1, both diffuse large B-cell lymphoma cell lines. Acute application of venetoclax did also not dysregulate Ca(2+) signaling in these Bcl-2-dependent cancer cells. Moreover, venetoclax-induced cell death was independent of intracellular Ca(2+) overload, since Ca(2+) buffering using BAPTA-AM did not suppress venetoclax-induced cell death. This study therefore shows that venetoclax does not dysregulate the intracellular Ca(2+) homeostasis in a variety of cell types, which may underlie its limited toxicity in human patients. Furthermore, venetoclax-induced cell death in Bcl-2-dependent cancer cells is not mediated by intracellular Ca(2+) overload. This article is part of a Special Issue entitled: ECS Meeting edited by Claus Heizmann, Joachim Krebs and Jacques Haiech.

  18. p53 and bcl-2 expression in high-grade B-cell lymphomas: correlation with survival time.

    PubMed Central

    Piris, M. A.; Pezzella, F.; Martinez-Montero, J. C.; Orradre, J. L.; Villuendas, R.; Sanchez-Beato, M.; Cuena, R.; Cruz, M. A.; Martinez, B.; Pezella F [corrected to Pezzella, F. ].

    1994-01-01

    B-cell high-grade lymphomas are heterogeneous in terms of histology, clinical presentation, treatment response and prognosis. As bcl-2 and p53 gene deregulations are frequently involved in several types of lymphoid malignancies, we aimed our investigation at the study of the relation between bcl-2 and p53 expression and survival probability in a group of 119 patients with B-cell high-grade lymphoma. These were obtained from the Virgen de la Salud Hospital, Toledo, Spain (73 cases), John Radcliffe Hospital, Oxford, UK (31 cases), and the Istituto Nazionale dei Tumori, Milan, Italy (15 cases). The relation between bcl-2 protein expression and survival was small, depending on the primary localisation of the tumour (in lymph node of mucosae), and lacked a significant correlation with overall survival. In contrast with this, p53 expression was related to survival probability in our series, this relation being both significant and independent of histological diagnosis. p53-positive patients showed a sudden decrease in life expectancy in the first months after diagnosis. Multivariant regression analysis confirmed that the only parameters significantly related with survival were extranodal origin, which is associated with a better prognosis, and p53 expression, which indicates a poor prognosis. Simultaneous expression of bcl-2 and p53 was associated with a poorer prognosis than p53 alone. This is particularly significant for large B-cell lymphomas presenting in lymph nodes. The cumulative poor effect of both p53 and bcl-2 in large B-cell lymphomas, which is more significant in nodal tumours, could confirm the existence of a multistep genetic deregulation in non-Hodgkin's lymphoma. This indicates that the genetic mechanisms controlling apoptosis and their disregulation are critical steps in the progression of lymphomas. PMID:8297731

  19. Identification of a novel regulatory domain in Bcl-X(L) and Bcl-2.

    PubMed Central

    Chang, B S; Minn, A J; Muchmore, S W; Fesik, S W; Thompson, C B

    1997-01-01

    Bcl-X(L), a member of the Bcl-2 family, can inhibit many forms of programed cell death. The three-dimensional structure of Bcl-X(L) identified a 60 amino acid loop lacking defined structure. Although amino acid sequence within this region is not conserved among Bcl-2 family members, structural modeling suggested that Bcl-2 also contains a large unstructured region. Compared with the full-length protein, loop deletion mutants of Bcl-X(L) and Bcl-2 displayed an enhanced ability to inhibit apoptosis. Despite enhanced function, the deletion mutants did not have significant alterations in the ability to bind pro-apoptotic proteins such as Bax. The loop deletion mutant of Bcl-2 also displayed a qualitative difference in its ability to inhibit apoptosis. Full-length Bcl-2 was unable to prevent anti-IgM-induced cell death of the immature B cell line WEHI-231. In contrast, the Bcl-2 deletion mutant protected WEHI-231 cells from death. Substantial differences were observed in the ability of WEHI-231 cells to phosphorylate the deletion mutant of Bcl-2 compared with full-length Bcl-2. Bcl-2 phosphorylation was found to be dependent on the presence of an intact loop domain. These results suggest that the loop domain in Bcl-X(L) and Bcl-2 can suppress the anti-apoptotic function of these genes and may be a target for regulatory post-translational modifications. PMID:9118958

  20. MicroRNAs affect BCL-2 family proteins in the setting of cerebral ischemia.

    PubMed

    Ouyang, Yi-Bing; Giffard, Rona G

    2014-11-01

    The BCL-2 family is centrally involved in the mechanism of cell death after cerebral ischemia. It is well known that the proteins of the BCL-2 family are key regulators of apoptosis through controlling mitochondrial outer membrane permeabilization. Recent findings suggest that many BCL-2 family members are also directly involved in controlling transmission of Ca(2+) from the endoplasmic reticulum (ER) to mitochondria through a specialization called the mitochondria-associated ER membrane (MAM). Increasing evidence supports the involvement of microRNAs (miRNAs), some of them targeting BCL-2 family proteins, in the regulation of cerebral ischemia. In this mini-review, after highlighting current knowledge about the multiple functions of BCL-2 family proteins and summarizing their relationship to outcome from cerebral ischemia, we focus on the regulation of BCL-2 family proteins by miRNAs, especially miR-29 which targets multiple BCL-2 family proteins.

  1. Bax transmembrane domain interacts with prosurvival Bcl-2 proteins in biological membranes

    PubMed Central

    Andreu-Fernández, Vicente; Sancho, Mónica; Genovés, Ainhoa; Lucendo, Estefanía; Todt, Franziska; Lauterwasser, Joachim; Funk, Kathrin; Jahreis, Günther; Pérez-Payá, Enrique; Mingarro, Ismael; Edlich, Frank; Orzáez, Mar

    2017-01-01

    The Bcl-2 (B-cell lymphoma 2) protein Bax (Bcl-2 associated X, apoptosis regulator) can commit cells to apoptosis via outer mitochondrial membrane permeabilization. Bax activity is controlled in healthy cells by prosurvival Bcl-2 proteins. C-terminal Bax transmembrane domain interactions were implicated recently in Bax pore formation. Here, we show that the isolated transmembrane domains of Bax, Bcl-xL (B-cell lymphoma-extra large), and Bcl-2 can mediate interactions between Bax and prosurvival proteins inside the membrane in the absence of apoptotic stimuli. Bcl-2 protein transmembrane domains specifically homooligomerize and heterooligomerize in bacterial and mitochondrial membranes. Their interactions participate in the regulation of Bcl-2 proteins, thus modulating apoptotic activity. Our results suggest that interactions between the transmembrane domains of Bax and antiapoptotic Bcl-2 proteins represent a previously unappreciated level of apoptosis regulation. PMID:28028215

  2. TIC10/ONC201 synergizes with Bcl-2/Bcl-xL inhibition in glioblastoma by suppression of Mcl-1 and its binding partners in vitro and in vivo.

    PubMed

    Karpel-Massler, Georg; Bâ, Maïmouna; Shu, Chang; Halatsch, Marc-Eric; Westhoff, Mike-Andrew; Bruce, Jeffrey N; Canoll, Peter; Siegelin, Markus D

    2015-11-03

    Glioblastoma is the most frequent primary brain tumor in adults. Current therapeutic options are sparse and the prognosis of patients suffering from this disease is grim. Abundance in intratumoral heterogeneity among different deregulated signaling pathways is a hallmark of glioblastoma and likely accounts for its recurrence and resistance to treatment. Glioblastomas harbor a plethora of deregulated pathways driving tumor formation and growth. In this study, we show that TIC10/ONC201, a promising compound that is currently in planned clinical development, along with Bcl-2/Bcl-xL inhibition by ABT263 yields a strong synergistic antiproliferative effect on pediatric, adult, proneural glioblastoma and glioma stem-like cells. On the molecular level, treatment with TIC10/ONC201 results in a posttranslational decrease of the anti-apoptotic Bcl-2 family member, myeloid cell leukemia 1 (Mcl-1), through modulation of the chaperone Bag3 and the deubiquitinase Usp9X. Consistently, the combination treatment of TIC10/ONC201 and ABT263 required the presence of functional BAX and BAK to drive intrinsic apoptosis, but is surprisingly independent of the extrinsic apoptotic pathway. Moreover, the expression of Noxa protein was required for efficient apoptosis induction by TIC10/ONC201 and ABT263. Importantly, the drug combination of TIC10/ONC201 and the BH3-mimetic, ABT263, led to a regression of tumors in vivo, without any notable toxicity and side effects. Overall, TIC10/ONC201 along with Bcl-2/Bcl-xL inhibition holds significant promise as a novel potential approach for the treatment of recalcitrant tumors such as glioblastoma.

  3. Mitochondrial PKM2 regulates oxidative stress-induced apoptosis by stabilizing Bcl2

    PubMed Central

    Liang, Ji; Cao, Ruixiu; Wang, Xiongjun; Zhang, Yajuan; Wang, Pan; Gao, Hong; Li, Chen; Yang, Fan; Zeng, Rong; Wei, Ping; Li, Dawei; Li, Wenfeng; Yang, Weiwei

    2017-01-01

    Pyruvate kinase M2 isoform (PKM2) catalyzes the last step of glycolysis and plays an important role in tumor cell proliferation. Recent studies have reported that PKM2 also regulates apoptosis. However, the mechanisms underlying such a role of PKM2 remain elusive. Here we show that PKM2 translocates to mitochondria under oxidative stress. In the mitochondria, PKM2 interacts with and phosphorylates Bcl2 at threonine (T) 69. This phosphorylation prevents the binding of Cul3-based E3 ligase to Bcl2 and subsequent degradation of Bcl2. A chaperone protein, HSP90α1, is required for this function of PKM2. HSP90α1's ATPase activity launches a conformational change of PKM2 and facilitates interaction between PKM2 and Bcl2. Replacement of wild-type Bcl2 with phosphorylation-deficient Bcl2 T69A mutant sensitizes glioma cells to oxidative stress-induced apoptosis and impairs brain tumor formation in an orthotopic xenograft model. Notably, a peptide that is composed of the amino acid residues from 389 to 405 of PKM2, through which PKM2 binds to Bcl2, disrupts PKM2-Bcl2 interaction, promotes Bcl2 degradation and impairs brain tumor growth. In addition, levels of Bcl2 T69 phosphorylation, conformation-altered PKM2 and Bcl2 protein correlate with one another in specimens of human glioblastoma patients. Moreover, levels of Bcl2 T69 phosphorylation and conformation-altered PKM2 correlate with both grades and prognosis of glioma malignancy. Our findings uncover a novel mechanism through which mitochondrial PKM2 phosphorylates Bcl2 and inhibits apoptosis directly, highlight the essential role of PKM2 in ROS adaptation of cancer cells, and implicate HSP90-PKM2-Bcl2 axis as a potential target for therapeutic intervention in glioblastoma. PMID:28035139

  4. Bcl-2 silencing attenuates hypoxia-induced apoptosis resistance in pulmonary microvascular endothelial cells.

    PubMed

    Cao, Yongmei; Jiang, Zhen; Zeng, Zhen; Liu, Yujing; Gu, Yuchun; Ji, Yingying; Zhao, Yupeng; Li, Yingchuan

    2016-01-01

    Pulmonary arterial hypertension (PAH) is a life-threatening disorder that ultimately causes heart failure. While the underlying causes of this condition are not well understood, previous studies suggest that the anti-apoptotic nature of pulmonary microvascular endothelial cells (PMVECs) in hypoxic environments contributes to PAH pathogenesis. In this study, we focus on the contribution of Bcl-2 and hypoxia response element (HRE) to apoptosis-resistant endothelial cells and investigate the mechanism. PMVECs obtained from either normal rats or apoptosis-resistant PMVECs obtained from PAH rats were transduced with recombinant lentiviral vectors carrying either Bcl-2-shRNA or HRE combined Bcl-2-shRNA, and then cultured these cells for 24 h under hypoxic (5% O2) or normoxic (21% O2) conditions. In normal PMVECs, Bcl-2-shRNA or HRE combined with Bcl-2-shRNA transduction successfully decreased Bcl-2 expression, while increasing apoptosis as well as caspase-3 and P53 expression in a normoxic environment. In a hypoxic environment, the effects of Bcl-2-shRNA treatment on cell apoptosis, and on Bcl-2, caspase-3, P53 expression were significantly suppressed. Conversely, HRE activation combined with Bcl-2-shRNA transduction markedly enhanced cell apoptosis and upregulated caspase-3 and P53 expression, while decreasing Bcl-2 expression. Furthermore, in apoptosis-resistant PMVECs, HRE-mediated Bcl-2 silencing effectively enhanced cell apoptosis and caspase-3 activity. The apoptosis rate was significantly depressed when Lv-HRE-Bcl-2-shRNA was combined with Lv-P53-shRNA or Lv-caspase3-shRNA transduction in a hypoxic environment. These results suggest that HRE-mediated Bcl-2 inhibition can effectively attenuate hypoxia-induced apoptosis resistance in PMVECs by downregulating Bcl-2 expression and upregulating caspase-3 and P53 expression. This study therefore reveals critical insight into potential therapeutic targets for treating PAH.

  5. Oxygen diffusion pathways in a cofactor-independent dioxygenase

    PubMed Central

    Di Russo, Natali V.; Condurso, Heather L.; Li, Kunhua; Bruner, Steven D.; Roitberg, Adrian E.

    2015-01-01

    Molecular oxygen plays an important role in a wide variety of enzymatic reactions. Through recent research efforts combining computational and experimental methods a new view of O2 diffusion is emerging, where specific channels guide O2 to the active site. The focus of this work is DpgC, a cofactor-independent oxygenase. Molecular dynamics simulations, together with mutagenesis experiments and xenon-binding data, reveal that O2 reaches the active site of this enzyme using three main pathways and four different access points. These pathways connect a series of dynamic hydrophobic pockets, concentrating O2 at a specific face of the enzyme substrate. Extensive molecular dynamics simulations provide information about which pathways are more frequently used. This data is consistent with the results of kinetic measurements on mutants and is difficult to obtain using computational cavity-location methods. Taken together, our results reveal that although DpgC is rare in its ability of activating O2 in the absence of cofactors or metals, the way O2 reaches the active site is similar to that reported for other O2-using proteins: multiple access channels are available, and the architecture of the pathway network can provide regio- and stereoselectivity. Our results point to the existence of common themes in O2 access that are conserved among very different types of proteins. PMID:26508997

  6. Both the Caspase CSP-1 and a Caspase-Independent Pathway Promote Programmed Cell Death in Parallel to the Canonical Pathway for Apoptosis in Caenorhabditis elegans

    PubMed Central

    Denning, Daniel P.; Hatch, Victoria; Horvitz, H. Robert

    2013-01-01

    Caspases are cysteine proteases that can drive apoptosis in metazoans and have critical functions in the elimination of cells during development, the maintenance of tissue homeostasis, and responses to cellular damage. Although a growing body of research suggests that programmed cell death can occur in the absence of caspases, mammalian studies of caspase-independent apoptosis are confounded by the existence of at least seven caspase homologs that can function redundantly to promote cell death. Caspase-independent programmed cell death is also thought to occur in the invertebrate nematode Caenorhabditis elegans. The C. elegans genome contains four caspase genes (ced-3, csp-1, csp-2, and csp-3), of which only ced-3 has been demonstrated to promote apoptosis. Here, we show that CSP-1 is a pro-apoptotic caspase that promotes programmed cell death in a subset of cells fated to die during C. elegans embryogenesis. csp-1 is expressed robustly in late pachytene nuclei of the germline and is required maternally for its role in embryonic programmed cell deaths. Unlike CED-3, CSP-1 is not regulated by the APAF-1 homolog CED-4 or the BCL-2 homolog CED-9, revealing that csp-1 functions independently of the canonical genetic pathway for apoptosis. Previously we demonstrated that embryos lacking all four caspases can eliminate cells through an extrusion mechanism and that these cells are apoptotic. Extruded cells differ from cells that normally undergo programmed cell death not only by being extruded but also by not being engulfed by neighboring cells. In this study, we identify in csp-3; csp-1; csp-2 ced-3 quadruple mutants apoptotic cell corpses that fully resemble wild-type cell corpses: these caspase-deficient cell corpses are morphologically apoptotic, are not extruded, and are internalized by engulfing cells. We conclude that both caspase-dependent and caspase-independent pathways promote apoptotic programmed cell death and the phagocytosis of cell corpses in parallel to

  7. Proposal for a modified grading system based on mitotic index and Bcl2 provides objective determination of clinical outcome for patients with breast cancer.

    PubMed

    Abdel-Fatah, Tarek M A; Powe, Desmond G; Ball, Graham; Lopez-Garcia, Maria A; Habashy, Hany O; Green, Andrew R; Reis-Filho, Jorge S; Ellis, Ian O

    2010-12-01

    We hypothesized that the interaction between mitotic index (M) and Bcl2 could accurately discriminate between low- and high-grade breast cancer (BC) and provide a more objective measure of clinical outcome than histological grade, especially for patients with intermediate histological grade (G2), small size or oestrogen receptor (ER)-negative cancers. A well-characterized series of 1650 BCs with long-term follow-up was subjected to immunohistochemical analysis for Bcl2. Mitotic index (M) was assessed according to Nottingham Grading System (NGS) guidelines: M1: < 10 mitoses; M2: 10-18 mitoses; M3: > 18 mitoses. Results were validated in an independent series of patients (n = 245) uniformly treated with adjuvant anthracycline-based chemotherapy. Subsequently, BCs were classified according to the combined M/Bcl2 profile and compared with NGS. Multivariate Cox regression models using validated prognostic factors demonstrated that the subgroups defined by M/Bcl2 profile remained significantly associated with patients' outcome but also performed better than lymph node status and tumour size. Incorporation of the M/Bcl2 profile into the Nottingham Prognostic Index (NPI) reclassified twice as many patients into the excellent prognosis group, potentially improving decision-making and sparing patients unneeded systemic adjuvant therapy. Patients with M2-3/Bcl2- and M3/Bcl2+ (high risk) had a two- to three-fold increased risk of recurrence when treated with either adjuvant hormone therapy or anthracycline-based chemotherapy compared with those with M1/Bcl2 ± and M2/Bcl2+ (low risk) [HR = 3.4 (2.8-5.6); p < 0.0001 and HR = 2.3 (1.2-4.3); p = 0.0009]. In conclusion, a grading system defined by mitotic counting and Bcl2 expression accurately reclassified patients with NGS-G2, small tumour size or ER-negative cancers into two groups: low risk (NGS-G1-like) versus high risk (NGS-G3-like) of BC mortality and recurrence, improving prognosis and therapeutic planning.

  8. Attenuation of both apoptotic and necrotic actions of cadmium by Bcl-2.

    PubMed Central

    Ishido, Masami; Ohtsubo, Rieko; Adachi, Tatsumi; Kunimoto, Manabu

    2002-01-01

    We examined the effects of cadmium on the bcl-2 family of proteins--bcl-2, bax, bad, and bcl-xS/L--in cadmium-induced cytotoxicity. Addition of 10 microM cadmium to cultured porcine kidney LLC-PK(1) cells caused apoptosis. Western blot analyses revealed that cadmium markedly increased endogenous bcl-2 protein (to 3-4 times the level in wild-type cells) earlier than metallothionein induction, but that the metal did not enhance the induction of bax, bad, or bcl-xS proteins. Cadmium also induced the transcript of bcl-2, with the amount of bcl-2 reaching a maximum at 1-2 hr of exposure; this increase occurred earlier than cadmium-induced increase in the protooncogene such as c-myc. A cadmium-induced increase in endogenous bcl-2 protein was also seen in rat primary thymocytes. Overexpression of the bcl-2 protein by gene transfection prevented cadmium-induced apoptosis. Following the detection of apoptosis, lactate dehydrogenase release in the culture medium (a marker of necrosis) was observed, and this release was also inhibited by overexpression of bcl-2. Electron microscopic observations also supported the fact that cadmium induced apoptotic chromatin condensation at an early stage of exposure, followed by necrotic features of the cells, both of which were also inhibited by overexpression of bcl-2 proteins. Thus, our data demonstrated that both apoptotic and necrotic actions of cadmium were attenuated by bcl-2. PMID:11781163

  9. Bim/Bcl-2 balance is critical for maintaining naive and memory T cell homeostasis

    PubMed Central

    Wojciechowski, Sara; Tripathi, Pulak; Bourdeau, Tristan; Acero, Luis; Grimes, H. Leighton; Katz, Jonathan D.; Finkelman, Fred D.; Hildeman, David A.

    2007-01-01

    We examined the role of the antiapoptotic molecule Bcl-2 in combating the proapoptotic molecule Bim in control of naive and memory T cell homeostasis using Bcl-2−/− mice that were additionally deficient in one or both alleles of Bim. Naive T cells were significantly decreased in Bim+/−Bcl-2−/− mice, but were largely restored in Bim−/−Bcl-2−/− mice. Similarly, a synthetic Bcl-2 inhibitor killed wild-type, but not Bim−/−, T cells. Further, T cells from Bim+/−Bcl-2−/− mice died rapidly ex vivo and were refractory to cytokine-driven survival in vitro. In vivo, naive CD8+ T cells required Bcl-2 to combat Bim to maintain peripheral survival, whereas naive CD4+ T cells did not. In contrast, Bim+/−Bcl-2−/− mice generated relatively normal numbers of memory T cells after lymphocytic choriomeningitis virus infection. Accumulation of memory T cells in Bim+/−Bcl-2−/− mice was likely caused by their increased proliferative renewal because of the lymphopenic environment of the mice. Collectively, these data demonstrate a critical role for a balance between Bim and Bcl-2 in controlling homeostasis of naive and memory T cells. PMID:17591857

  10. Bcl2L13 is a ceramide synthase inhibitor in glioblastoma

    PubMed Central

    Jensen, Samuel A.; Calvert, Andrea E.; Volpert, Giora; Kouri, Fotini M.; Hurley, Lisa A.; Luciano, Janina P.; Wu, Yongfei; Chalastanis, Alexandra; Futerman, Anthony H.; Stegh, Alexander H.

    2014-01-01

    Therapy resistance is a major limitation to the successful treatment of cancer. Here, we identify Bcl2-like 13 (Bcl2L13), an atypical member of the Bcl-2 family, as a therapy susceptibility gene with elevated expression in solid and blood cancers, including glioblastoma (GBM). We demonstrate that mitochondria-associated Bcl2L13 inhibits apoptosis induced by a wide spectrum of chemo- and targeted therapies upstream of Bcl2-associated X protein activation and mitochondrial outer membrane permeabilization in vitro and promotes GBM tumor growth in vivo. Mechanistically, Bcl2L13 binds to proapoptotic ceramide synthases 2 (CerS2) and 6 (CerS6) via a unique C-terminal 250-aa sequence located between its Bcl-2 homology and membrane anchor domains and blocks homo- and heteromeric CerS2/6 complex formation and activity. Correspondingly, CerS2/6 activity and Bcl2L13 abundance are inversely correlated in GBM tumors. Thus, our genetic and functional studies identify Bcl2L13 as a regulator of therapy susceptibility and point to the Bcl2L13–CerS axis as a promising target to enhance responses of therapy-refractory cancers toward conventional and targeted regimens currently in clinical use. PMID:24706805

  11. Bcl2L13 is a ceramide synthase inhibitor in glioblastoma.

    PubMed

    Jensen, Samuel A; Calvert, Andrea E; Volpert, Giora; Kouri, Fotini M; Hurley, Lisa A; Luciano, Janina P; Wu, Yongfei; Chalastanis, Alexandra; Futerman, Anthony H; Stegh, Alexander H

    2014-04-15

    Therapy resistance is a major limitation to the successful treatment of cancer. Here, we identify Bcl2-like 13 (Bcl2L13), an atypical member of the Bcl-2 family, as a therapy susceptibility gene with elevated expression in solid and blood cancers, including glioblastoma (GBM). We demonstrate that mitochondria-associated Bcl2L13 inhibits apoptosis induced by a wide spectrum of chemo- and targeted therapies upstream of Bcl2-associated X protein activation and mitochondrial outer membrane permeabilization in vitro and promotes GBM tumor growth in vivo. Mechanistically, Bcl2L13 binds to proapoptotic ceramide synthases 2 (CerS2) and 6 (CerS6) via a unique C-terminal 250-aa sequence located between its Bcl-2 homology and membrane anchor domains and blocks homo- and heteromeric CerS2/6 complex formation and activity. Correspondingly, CerS2/6 activity and Bcl2L13 abundance are inversely correlated in GBM tumors. Thus, our genetic and functional studies identify Bcl2L13 as a regulator of therapy susceptibility and point to the Bcl2L13-CerS axis as a promising target to enhance responses of therapy-refractory cancers toward conventional and targeted regimens currently in clinical use.

  12. Topographic distribution of bcl-2 protein in feline tissues in health and neoplasia.

    PubMed

    Madewell, B R; Gandour-Edwards, R; Edwards, B F; Walls, J E; Griffey, S M

    1999-11-01

    The bcl-2 family of genes encodes proteins that influence apoptosis. In the present immunohistochemical study, the topographic distribution of bcl-2 protein was examined in healthy feline fetal, neonatal, and adult tissues, a feline renal cell line, and feline tumors obtained from a veterinary hospital. The topographic distribution of bcl-2 in healthy tissues was similar to that described in human tissues. In lymphoid tissues, follicular mantle cells strongly expressed bcl-2. In complex and differentiating epithelium, bcl-2 expression was detected in stem cell and proliferation zones. Bcl-2 expression was also detected in lower crypts of the intestine and in skin basal layers. The feline Crandell kidney cells expressed bcl-2 diffusely throughout the cytoplasm. Of 180 tumors examined, bcl-2 was expressed almost uniformly in cutaneous basal cell tumors, thyroid adenomas, and mammary carcinomas and in 50% of the lymphomas examined. Bcl-2 may play a role in blocking apoptotic cell death in a broad range of normal feline tissues, whereas dysregulated bcl-2 may extend the life of certain tumors or render certain tumors resistant to therapy because most chemotherapeutic and radiotherapeutic agents eliminate tumor cells by triggering apoptosis.

  13. Bim/Bcl-2 balance is critical for maintaining naive and memory T cell homeostasis.

    PubMed

    Wojciechowski, Sara; Tripathi, Pulak; Bourdeau, Tristan; Acero, Luis; Grimes, H Leighton; Katz, Jonathan D; Finkelman, Fred D; Hildeman, David A

    2007-07-09

    We examined the role of the antiapoptotic molecule Bcl-2 in combating the proapoptotic molecule Bim in control of naive and memory T cell homeostasis using Bcl-2(-/-) mice that were additionally deficient in one or both alleles of Bim. Naive T cells were significantly decreased in Bim(+/-)Bcl-2(-/-) mice, but were largely restored in Bim(-/-)Bcl-2(-/-) mice. Similarly, a synthetic Bcl-2 inhibitor killed wild-type, but not Bim(-/-), T cells. Further, T cells from Bim(+/-)Bcl-2(-/-) mice died rapidly ex vivo and were refractory to cytokine-driven survival in vitro. In vivo, naive CD8(+) T cells required Bcl-2 to combat Bim to maintain peripheral survival, whereas naive CD4(+) T cells did not. In contrast, Bim(+/-)Bcl-2(-/-) mice generated relatively normal numbers of memory T cells after lymphocytic choriomeningitis virus infection. Accumulation of memory T cells in Bim(+/-)Bcl-2(-/-) mice was likely caused by their increased proliferative renewal because of the lymphopenic environment of the mice. Collectively, these data demonstrate a critical role for a balance between Bim and Bcl-2 in controlling homeostasis of naive and memory T cells.

  14. Bcl-2 associated with positive symptoms of schizophrenic patients in an acute phase.

    PubMed

    Tsai, Meng-Chang; Liou, Chia-Wei; Lin, Tsu-Kung; Lin, I-Mei; Huang, Tiao-Lai

    2013-12-30

    B cell lymphoma protein-2 (Bcl-2) may contribute to the pathophysiology of schizophrenia in the brain. The aim of this study was to investigate the serum levels of Bcl-2 in schizophrenic patients in an acute phase, and evaluate Bcl-2 level changes after antipsychotic treatment. We consecutively enrolled 41 schizophrenia patients in an acute phase; 28 were followed up with a 4-week antipsychotic treatment. Serum Bcl-2 levels were measured with assay kits. All patients were evaluated by examining the correlation between Bcl-2 levels and Positive and Negative Syndrome Scale (PANSS) scores, using Pearson correlation coefficients. In schizophrenic patients in an acute phase, positive PANSS subscores were significantly negatively correlated with Bcl-2 levels. In addition, we found Bcl-2 levels had a significantly negative correlation with PANSS total scores and positive subscores in male patients in an acute phase. Using the paired t-test, we found no significant changes in Bcl-2 levels in schizophrenia patients who had received the 4-week treatment with antipsychotic drugs (n=28). In conclusion, our results suggest that Bcl-2 might be an indicator of schizophrenia severity in the acute phase. In addition, Bcl-2 levels might be associated with positive symptoms in male patients with schizophrenia.

  15. Borax-induced apoptosis in HepG2 cells involves p53, Bcl-2, and Bax.

    PubMed

    Wei, Y; Yuan, F J; Zhou, W B; Wu, L; Chen, L; Wang, J J; Zhang, Y S

    2016-06-21

    Borax, a boron compound and a salt of boric acid, is known to inhibit the growth of tumor cells. HepG2 cells have been shown to be clearly susceptible to the anti-proliferative effects of borax. However, the specific mechanisms regulating this effect are poorly understood. This study aimed to investigate the pathways underlying the growth inhibition induced by borax in HepG2 cells. The effects of borax on HepG2 cell viability were characterized using MTT. Apoptosis was also verified by annexin V/propidium iodide staining. JC-1 dye and western blotting techniques were used to measure mitochondrial membrane potential and p53, Bax, and Bcl-2 protein expression, respectively. Relevant mRNA levels were measured by qRT-PCR. Borax inhibited the proliferation of HepG2 cells in a time- and dose-dependent manner in vitro. The apoptotic process triggered by borax involved the upregulation of p53 and Bax and the downregulation of Bcl-2, which was confirmed by a change in the mitochondrial membrane potential. These results elucidate a borax-induced apoptotic pathway in HepG2 cells that involves the upregulation of p53 and Bax and the downregulation of Bcl-2.

  16. A Surface Groove Essential for Viral Bcl-2 Function During Chronic Infection In Vivo

    PubMed Central

    Petros, Andrew M; Nettesheim, David; van Dyk, Linda F.; Labrada, Lucia; Speck, Samuel H; Levine, Beth

    2005-01-01

    Antiapoptotic Bcl-2 family proteins inhibit apoptosis in cultured cells by binding BH3 domains of proapoptotic Bcl-2 family members via a hydrophobic BH3 binding groove on the protein surface. We investigated the physiological importance of the BH3 binding groove of an antiapoptotic Bcl-2 protein in mammals in vivo by analyzing a viral Bcl-2 family protein. We show that the γ-herpesvirus 68 (γHV68) Bcl-2 family protein (γHV68 v-Bcl-2), which is known to inhibit apoptosis in cultured cells, inhibits both apoptosis in primary lymphocytes and Bax toxicity in yeast. Nuclear magnetic resonance determination of the γHV68 v-Bcl-2 structure revealed a BH3 binding groove that binds BH3 domain peptides from proapoptotic Bcl-2 family members Bax and Bak via a molecular mechanism shared with host Bcl-2 family proteins, involving a conserved arginine in the BH3 peptide binding groove. Mutations of this conserved arginine and two adjacent amino acids to alanine (SGR to AAA) within the BH3 binding groove resulted in a properly folded protein that lacked the capacity of the wild-type γHV68 v-Bcl-2 to bind Bax BH3 peptide and to block Bax toxicity in yeast. We tested the physiological importance of this v-Bcl-2 domain during viral infection by engineering viral mutants encoding a v-Bcl-2 containing the SGR to AAA mutation. This mutation resulted in a virus defective for both efficient reactivation of γHV68 from latency and efficient persistent γHV68 replication. These studies demonstrate an essential functional role for amino acids in the BH3 peptide binding groove of a viral Bcl-2 family member during chronic infection. PMID:16201011

  17. BCL2L2 — EDRN Public Portal

    Cancer.gov

    From NCBI Gene: This gene encodes a member of the BCL-2 protein family. The proteins of this family form hetero- or homodimers and act as anti- and pro-apoptotic regulators. Expression of this gene in cells has been shown to contribute to reduced cell apoptosis under cytotoxic conditions. Studies of the related gene in mice indicated a role in the survival of NGF- and BDNF-dependent neurons. Mutation and knockout studies of the mouse gene demonstrated an essential role in adult spermatogenesis. Alternative splicing results in multiple transcript variants. Read-through transcription also exists between this gene and the neighboring downstream PABPN1 (poly(A) binding protein, nuclear 1) gene. [provided by RefSeq, Dec 2010

  18. Artesunate induces apoptosis through caspase-dependent and -independent mitochondrial pathways in human myelodysplastic syndrome SKM-1 cells.

    PubMed

    Wang, Ying; Yang, Jingci; Chen, Li; Wang, Jiamin; Wang, Yaqian; Luo, Jianmin; Pan, Ling; Zhang, Xuejun

    2014-08-05

    Artesunate (ART) is a semi-synthetic derivative of artemisinin extracted from Artemisia annua (sweet wormwood) that is conventionally used in anti-malarial drugs and more recently in medications that induce tumor cell apoptosis. Here, we investigated the effects and mechanistic pathways of ART in human myelodysplastic syndrome (MDS), a condition that commonly progresses to acute myeloid leukemia (AML). Human MDS SKM-1 cells, primary bone marrow (PBM) mononuclear cells from patients with refractory anemia with excess blasts (RAEB) or MDS-AML (MDS cell group), and PBM stromal cells from three patients without hematological diseases (non-MDS cell group) were cultured for 24, 48, or 72 h with or without various ART concentrations. CCK-8, western blot, JC-1 fluorescence, and Annexin-V/Propidium iodide (PI) labeling were used to assess cell proliferation, protein levels, mitochondrial membrane potentials (MMPs) and apoptosis, respectively. ART administration dose- and time-dependently inhibited SKM-1 proliferation. At 24, 48, and 72 h, ART IC₅₀ values were 89.92, 4.24, and 1.28 μmol/L, respectively. ART only significantly inhibited proliferation in the MDS cell group, but it has little impact on proliferation of non-MDS cells. ART decreased MMPs, and dose-dependently induced SKM-1 cell apoptosis, peaking at 82.9% when treated with 200 μmol/L ART for 24h. Caspase-3 and -9 activation, poly(ADP-ribose) polymerase cleavage, decreased Bcl-2/Bax ratio and apoptosis inducing factor nuclear localization were implicated in apoptosis. Our results indicate that ART effectively induces apoptosis in SKM-1 cells through both caspase-dependent and -independent mitochondrial pathways.

  19. Bcl-2 upregulation by HIV-1 Tat during infection of primary human macrophages in culture.

    PubMed

    Zhang, Mingjie; Li, Xingxiang; Pang, Xiaowu; Ding, Lina; Wood, Owen; Clouse, Kathleen A; Hewlett, Indira; Dayton, Andrew I

    2002-01-01

    The ability of cells of the human monocyte/macrophage lineage to host HIV-1 replication while resisting cell death is believed to significantly contribute to their ability to serve as a reservoir for viral replication in the host. Although macrophages are generally resistant to apoptosis, interruption of anti-apoptotic pathways can render them susceptible to apoptosis. Here we report that HIV-1(BAL )infection of primary human monocyte-derived macrophages (MDM) upregulates the mRNA and protein levels of the anti-apoptic gene, Bcl-2. Furthermore, this upregulation can be quantitatively mimicked by treating MDM with soluble HIV-1 Tat-86 protein. These results suggest that in infecting cells of the monocyte/macrophage lineage, HIV-1 may be benefiting from additional protection against apoptosis caused by specific upregulation of cellular anti-apoptotic genes.

  20. Mito-priming as a method to engineer Bcl-2 addiction.

    PubMed

    Lopez, Jonathan; Bessou, Margaux; Riley, Joel S; Giampazolias, Evangelos; Todt, Franziska; Rochegüe, Tony; Oberst, Andrew; Green, Douglas R; Edlich, Frank; Ichim, Gabriel; Tait, Stephen W G

    2016-02-02

    Most apoptotic stimuli require mitochondrial outer membrane permeabilization (MOMP) in order to execute cell death. As such, MOMP is subject to tight control by Bcl-2 family proteins. We have developed a powerful new technique to investigate Bcl-2-mediated regulation of MOMP. This method, called mito-priming, uses co-expression of pro- and anti-apoptotic Bcl-2 proteins to engineer Bcl-2 addiction. On addition of Bcl-2 targeting BH3 mimetics, mito-primed cells undergo apoptosis in a rapid and synchronous manner. Using this method we have comprehensively surveyed the efficacy of BH3 mimetic compounds, identifying potent and specific MCL-1 inhibitors. Furthermore, by combining different pro- and anti-apoptotic Bcl-2 pairings together with CRISPR/Cas9-based genome editing, we find that tBID and PUMA can preferentially kill in a BAK-dependent manner. In summary, mito-priming represents a facile and robust means to trigger mitochondrial apoptosis.

  1. miR-15 and miR-16 induce apoptosis by targeting BCL2.

    PubMed

    Cimmino, Amelia; Calin, George Adrian; Fabbri, Muller; Iorio, Marilena V; Ferracin, Manuela; Shimizu, Masayoshi; Wojcik, Sylwia E; Aqeilan, Rami I; Zupo, Simona; Dono, Mariella; Rassenti, Laura; Alder, Hansjuerg; Volinia, Stefano; Liu, Chang-Gong; Kipps, Thomas J; Negrini, Massimo; Croce, Carlo M

    2005-09-27

    Chronic lymphocytic leukemia (CLL) is the most common human leukemia and is characterized by predominantly nondividing malignant B cells overexpressing the antiapoptotic B cell lymphoma 2 (Bcl2) protein. miR-15a and miR-16-1 are deleted or down-regulated in the majority of CLLs. Here, we demonstrate that miR-15a and miR-16-1 expression is inversely correlated to Bcl2 expression in CLL and that both microRNAs negatively regulate Bcl2 at a posttranscriptional level. BCL2 repression by these microRNAs induces apoptopsis in a leukemic cell line model. Therefore, miR-15 and miR-16 are natural antisense Bcl2 interactors that could be used for therapy of Bcl2-overexpressing tumors.

  2. bcl-2 Overexpression Reduces Apoptotic Photoreceptor Cell Death in Three Different Retinal Degenerations

    NASA Astrophysics Data System (ADS)

    Chen, Jeannie; Flannery, John G.; Lavail, Matthew M.; Steinberg, Roy H.; Xu, Jun; Simon, Melvin I.

    1996-07-01

    Apoptosis of photoreceptors occurs infrequently in adult retina but can be triggered in inherited and environmentally induced retinal degenerations. The protooncogene bcl-2 is known to be a potent regulator of cell survival in neurons. We created lines of transgenic mice overexpressing bcl-2 to test for its ability to increase photoreceptor survival. Bcl-2 increased photoreceptor survival in mice with retinal degeneration caused by a defective opsin or cGMP phosphodiesterase. Overexpression of Bcl-2 in normal photoreceptors also decreased the damaging effects of constant light exposure. Apoptosis was induced in normal photoreceptors by very high levels of bcl-2. We conclude that bcl-2 is an important regulator of photoreceptor cell death in retinal degenerations.

  3. Loss of Bak enhances lymphocytosis but does not ameliorate thrombocytopaenia in BCL-2 transgenic mice.

    PubMed

    Vandenberg, C J; Josefsson, E C; Campbell, K J; James, C; Lawlor, K E; Kile, B T; Cory, S

    2014-05-01

    Bax and Bak are critical effectors of apoptosis. Although both are widely expressed and usually functionally redundant, recent studies suggest that Bak has particular importance in certain cell types. Genetic and biochemical studies indicate that Bak activation is prevented primarily by Mcl-1 and Bcl-xL, whereas Bax is held in check by all pro-survival Bcl-2 homologues, including Bcl-2 itself. In this study, we have investigated whether loss of Bak or elevated Mcl-1 modulates haemopoietic abnormalities provoked by overexpression of Bcl-2. The Mcl-1 transgene had little impact, probably because the expression level was insufficient to effectively reduce Bak activation. However, loss of Bak enhanced lymphocytosis in vavP-BCL-2 transgenic mice and increased resistance of their thymocytes to some cytotoxic agents, implying that Bak-specific signals can be triggered in certain lymphoid populations. Nevertheless, lack of Bak had no significant impact on thymic abnormalities in vavP-BCL-2tg mice, which kinetic analysis suggested was due to accumulation of self-reactive thymocytes that resist deletion. Intriguingly, although Bak(-/-) mice have elevated platelet counts, Bak(-/-)vavP-BCL-2 mice, like vavP-BCL-2 littermates, were thrombocytopaenic. To clarify why, the vavP-BCL-2 platelet phenotype was scrutinised more closely. Platelet life span was found to be elevated in vavP-BCL-2 mice, which should have provoked thrombocytosis, as in Bak(-/-) mice. Analysis of bone marrow chimaeric mice suggested the low platelet phenotype was due principally to extrinsic factors. Following splenectomy, blood platelets remained lower in vavP-BCL-2 than wild-type mice. However, in Rag1(-/-) BCL-2tg mice, platelet levels were normal, implying that elevated lymphocytes are primarily responsible for BCL-2tg-induced thrombocytopaenia.

  4. Loss of Bak enhances lymphocytosis but does not ameliorate thrombocytopaenia in BCL-2 transgenic mice

    PubMed Central

    Vandenberg, C J; Josefsson, E C; Campbell, K J; James, C; Lawlor, K E; Kile, B T; Cory, S

    2014-01-01

    Bax and Bak are critical effectors of apoptosis. Although both are widely expressed and usually functionally redundant, recent studies suggest that Bak has particular importance in certain cell types. Genetic and biochemical studies indicate that Bak activation is prevented primarily by Mcl-1 and Bcl-xL, whereas Bax is held in check by all pro-survival Bcl-2 homologues, including Bcl-2 itself. In this study, we have investigated whether loss of Bak or elevated Mcl-1 modulates haemopoietic abnormalities provoked by overexpression of Bcl-2. The Mcl-1 transgene had little impact, probably because the expression level was insufficient to effectively reduce Bak activation. However, loss of Bak enhanced lymphocytosis in vavP-BCL-2 transgenic mice and increased resistance of their thymocytes to some cytotoxic agents, implying that Bak-specific signals can be triggered in certain lymphoid populations. Nevertheless, lack of Bak had no significant impact on thymic abnormalities in vavP-BCL-2tg mice, which kinetic analysis suggested was due to accumulation of self-reactive thymocytes that resist deletion. Intriguingly, although Bak−/− mice have elevated platelet counts, Bak−/−vavP-BCL-2 mice, like vavP-BCL-2 littermates, were thrombocytopaenic. To clarify why, the vavP-BCL-2 platelet phenotype was scrutinised more closely. Platelet life span was found to be elevated in vavP-BCL-2 mice, which should have provoked thrombocytosis, as in Bak−/− mice. Analysis of bone marrow chimaeric mice suggested the low platelet phenotype was due principally to extrinsic factors. Following splenectomy, blood platelets remained lower in vavP-BCL-2 than wild-type mice. However, in Rag1−/− BCL-2tg mice, platelet levels were normal, implying that elevated lymphocytes are primarily responsible for BCL-2tg-induced thrombocytopaenia. PMID:24464220

  5. Prognostic value of mitotic index and Bcl2 expression in male breast cancer.

    PubMed

    Lacle, Miangela M; van der Pol, Carmen; Witkamp, Arjen; van der Wall, Elsken; van Diest, Paul J

    2013-01-01

    The incidence of male breast cancer (MBC) is rising. Current treatment regimens for MBC are extrapolated from female breast cancer (FBC), based on the assumption that FBC prognostic features and therapeutic targets can be extrapolated to MBC. However, there is yet little evidence that prognostic features that have been developed and established in FBC are applicable to MBC as well. In a recent study on FBC, a combination of mitotic index and Bcl2 expression proved to be of strong prognostic value. Previous papers on Bcl2 expression in MBC were equivocal, and the prognostic value of Bcl2 combined with mitotic index has not been studied in MBC. The aim of the present study was therefore to investigate the prognostic value of Bcl2 in combination with mitotic index in MBC. Immunohistochemical staining for Bcl2 was performed on tissue microarrays of a total of 151 male breast cancer cases. Mitotic index was scored. The prognostic value of Bcl2 expression and Bcl2/mitotic index combinations was evaluated studying their correlations with clinicopathologic features and their prediction of survival. The vast majority of MBC (94%) showed Bcl2 expression, more frequently than previously described for FBC. Bcl2 expression had no significant associations with clinicopathologic features such as tumor size, mitotic count and grade. In univariate survival analysis, Bcl2 had no prognostic value, and showed no additional prognostic value to tumor size and histological grade in Cox regression. In addition, the Bcl2/mitotic index combination as opposed to FBC did not predict survival in MBC. In conclusion, Bcl2 expression is common in MBC, but is not associated with major clinicopathologic features and, in contrast to FBC, does not seem to have prognostic value, also when combined with mitotic index.

  6. A novel role for Bcl-2 in regulation of cellular calcium extrusion.

    PubMed

    Ferdek, Pawel E; Gerasimenko, Julia V; Peng, Shuang; Tepikin, Alexei V; Petersen, Ole H; Gerasimenko, Oleg V

    2012-07-10

    The antiapoptotic protein Bcl-2 plays important roles in Ca(2+) signaling by influencing inositol triphosphate receptors and regulating Ca(2+)-induced Ca(2+) release. Here we investigated whether Bcl-2 affects Ca(2+) extrusion in pancreatic acinar cells. We specifically blocked the Ca(2+) pumps in the endoplasmic reticulum and assessed the rate at which the cells reduced an elevated cytosolic Ca(2+) concentration after a period of enhanced Ca(2+) entry. Because external Ca(2+) was removed and endoplasmic reticulum Ca(2+) pumps were blocked, Ca(2+) extrusion was the only process responsible for recovery. Cells lacking Bcl-2 restored the basal cytosolic Ca(2+) level much faster than control cells. The enhanced Ca(2+) extrusion in cells from Bcl-2 knockout (Bcl-2 KO) mice was not due to increased Na(+)/Ca(2+) exchange activity, because removal of external Na(+) did not influence the Ca(2+) extrusion rate. Overexpression of Bcl-2 in the pancreatic acinar cell line AR42J decreased Ca(2+) extrusion, whereas silencing Bcl-2 expression (siRNA) had the opposite effect. Loss of Bcl-2, while increasing Ca(2+) extrusion, dramatically decreased necrosis and promoted apoptosis induced by oxidative stress, whereas specific inhibition of Ca(2+) pumps in the plasma membrane (PMCA) with caloxin 3A1 reduced Ca(2+) extrusion and increased necrosis. Bcl-2 regulates PMCA function in pancreatic acinar cells and thereby influences cell fate.

  7. Antiapoptotic Bcl-2 protein as a potential target for cancer therapy: A mini review.

    PubMed

    Jagani, Hitesh; Kasinathan, Narayanan; Meka, Sreenivasa Reddy; Josyula, Venkata Rao

    2016-08-01

    Bcl-2, an antiapoptotic protein, is considered as a potential target in cancer treatment since its oncogenic potential has been proven and is well documented. Antisense technology and RNA interference (RNAi) have been used to reduce the expression of the Bcl-2 gene in many types of cancer cells and are effective as adjuvant therapy along with the chemotherapeutic agents. The lack of appropriate delivery systems is considered to be the main hurdle associated with the RNAi. In this review, we discuss the antiapoptotic Bcl-2 protein, its oncogenic potential, and various approaches utilized to target Bcl-2 including suitable delivery systems employed for successful delivery of siRNA.

  8. Bcl2-low-expressing MCF7 cells undergo necrosis rather than apoptosis upon staurosporine treatment.

    PubMed Central

    Poliseno, Laura; Bianchi, Laura; Citti, Lorenzo; Liberatori, Sabrina; Mariani, Laura; Salvetti, Alessandra; Evangelista, Monica; Bini, Luca; Pallini, Vitaliano; Rainaldi, Giuseppe

    2004-01-01

    We present a ribozyme-based strategy for studying the effects of Bcl2 down-regulation. The anti-bcl2 hammerhead ribozyme Rz-bcl2 was stably transfected into MCF7 cancer cells and the cleavage of Bcl2 mRNA was demonstrated using a new assay for cleavage product detection, while Western blot analysis showed a concomitant depletion of Bcl2 protein. Rz-bcl2-expressing cells were more sensitive to staurosporine than control cells. Moreover, both molecular and cellular read-outs indicated that staurosporine-induced cell death was necrosis rather than apoptosis in these cells. The study of the effects of Bcl2 down-regulation was extended to the global MCF7 protein expression profile, exploiting a proteomic approach. Two reference electro-pherograms of Rz-bcl2-transfected cells, one with the ribozyme in a catalytically active form and the other with the ribozyme in a catalytically inactive form, were obtained. When comparing the two-dimensional maps, 53 differentially expressed spots were found, four of which were identified by MALDI-TOF (matrix-assisted laser-desorption ionization-time-of-flight) MS as calreticulin, nucleophosmin, phosphoglycerate kinase and pyruvate kinase. How the up-regulation of these proteins might help to explain the modification of Bcl2 activity is discussed. PMID:14748742

  9. Protection against Fatal Sindbis Virus Encephalitis by Beclin, a Novel Bcl-2-Interacting Protein

    PubMed Central

    Liang, Xiao Huan; Kleeman, Linda K.; Jiang, Hui Hui; Gordon, Gerald; Goldman, James E.; Berry, Gail; Herman, Brian; Levine, Beth

    1998-01-01

    bcl-2, the prototypic cellular antiapoptotic gene, decreases Sindbis virus replication and Sindbis virus-induced apoptosis in mouse brains, resulting in protection against lethal encephalitis. To investigate potential mechanisms by which Bcl-2 protects against central nervous system Sindbis virus infection, we performed a yeast two-hybrid screen to identify Bcl-2-interacting gene products in an adult mouse brain library. We identified a novel 60-kDa coiled-coil protein, Beclin, which we confirmed interacts with Bcl-2 in mammalian cells, using fluorescence resonance energy transfer microscopy. To examine the role of Beclin in Sindbis virus pathogenesis, we constructed recombinant Sindbis virus chimeras that express full-length human Beclin (SIN/beclin), Beclin lacking the putative Bcl-2-binding domain (SIN/beclinΔBcl-2BD), or Beclin containing a premature stop codon near the 5′ terminus (SIN/beclinstop). The survival of mice infected with SIN/beclin was significantly higher (71%) than the survival of mice infected with SIN/beclinΔBcl-2BD (9%) or SIN/beclinstop (7%) (P < 0.001). The brains of mice infected with SIN/beclin had fewer Sindbis virus RNA-positive cells, fewer apoptotic cells, and lower viral titers than the brains of mice infected with SIN/beclinΔBcl-2BD or SIN/beclinstop. These findings demonstrate that Beclin is a novel Bcl-2-interacting cellular protein that may play a role in antiviral host defense. PMID:9765397

  10. Bax protein expression is increased in Alzheimer's brain: correlations with DNA damage, Bcl-2 expression, and brain pathology.

    PubMed

    Su, J H; Deng, G; Cotman, C W

    1997-01-01

    We have shown that many neurons in Alzheimer's disease (AD) exhibit terminal deoxynucleotidyl transferase (TdT) labeling for DNA strand breaks, and upregulation of Bcl-2 is associated with neurons exhibiting nuclear DNA fragmentation, while downregulation of Bcl-2 is associated with tangle-bearing neurons in AD brains. Consequently, we examined the expression of bcl-associated X (Bax) protein in AD brain. Immunoreactivity for Bax was seen in neurons and microglia of the hippocampal formation, and was elevated in the majority of AD cases as compared to control cases. Interestingly, 3 transitional cases, which had mild degeneration changes, exhibited relatively high levels of Bax immunoreactivity. Most Bax-positive neurons showed either TdT-labeled nuclei or Bcl-2 immunoreactivity. Although Bax immunoreactivity was detected within most early tangle-bearing neurons, many Bax-positive neurons did not colocalize with later-stage tangle-bearing neurons. In regions containing relatively few tangles in mild AD brains, many TdT-labeled neurons were immunolabeled with Bax antibody and most of them lacked evidence of neurofibrillary changes. These findings suggest that Bax may contribute to neuronal cell death in AD. Furthermore, DNA damage and the upregulation of Bax appear to precede tangle formation or may represent an alternative pathway of cell death in AD.

  11. Nicotine mediates oxidative stress and apoptosis through cross talk between NOX1 and Bcl-2 in lung epithelial cells.

    PubMed

    Zanetti, Filippo; Giacomello, Marta; Donati, Yves; Carnesecchi, Stephanie; Frieden, Maud; Barazzone-Argiroffo, Constance

    2014-11-01

    Nicotine contributes to the onset and progression of several pulmonary diseases. Among the various pathophysiological mechanisms triggered by nicotine, oxidative stress and cell death are reported in several cell types. We found that chronic exposure to nicotine (48h) induced NOX1-dependent oxidative stress and apoptosis in primary pulmonary cells. In murine (MLE-12) and human (BEAS-2B) lung epithelial cell lines, nicotine acted as a sensitizer to cell death and synergistically enhanced apoptosis when cells were concomitantly exposed to hyperoxia. The precise signaling pathway was investigated in MLE-12 cells in which NOX1 was abrogated by a specific inhibitor or stably silenced by shRNA. In the early phase of exposure (1h), nicotine mediated intracellular Ca(2+) fluxes and activation of protein kinase C, which in its turn activated NOX1, leading to cellular and mitochondrial oxidative stress. The latter triggered the intrinsic apoptotic machinery by modulating the expression of Bcl-2 and Bax. Overexpression of Bcl-2 completely prevented nicotine's detrimental effects, suggesting Bcl-2as a downstream key regulator in nicotine/NOX1-induced cell damage. These results suggest that NOX1 is a major contributor to the generation of intracellular oxidative stress induced by nicotine and might be an important molecule to target in nicotine-related lung pathologies.

  12. 4-Nonylphenol induces disruption of spermatogenesis associated with oxidative stress-related apoptosis by targeting p53-Bcl-2/Bax-Fas/FasL signaling.

    PubMed

    Duan, Peng; Hu, Chunhui; Butler, Holly J; Quan, Chao; Chen, Wei; Huang, Wenting; Tang, Sha; Zhou, Wei; Yuan, Meng; Shi, Yuqin; Martin, Francis L; Yang, Kedi

    2017-03-01

    4-Nonylphenol (NP) is a ubiquitous environmental chemical with estrogenic activity. Our aim was to test the hypothesis that pubertal exposure to NP leads to testicular dysfunction. Herein, 24 7-week-old rats were randomly divided into four groups and treated with NP (0, 25, 50, or 100 mg/kg body weight every 2 days for 20 consecutive days) by intraperitoneal injection. Compared to untreated controls, the parameters of sperm activation rate, curvilinear velocity, average path velocity, and swimming velocity were significantly lower at doses of 100 mg/kg, while sperm morphological abnormalities were higher, indicating functional disruption and reduced fertilization potential. High exposure to NP (100 mg/kg) resulted in disordered arrangement of spermatoblasts and reduction of spermatocytes in seminiferous tubules, while tissues exhibited a marked decline in testicular fructose content and serum FSH, LH, and testosterone levels. Oxidative stress was induced by NP (50 or 100 mg/kg) as evidenced by elevated MDA, decreased SOD and GSH-Px, and inhibited antioxidant gene expression (CAT, GPx, SOD1, and CYP1B1). In addition, NP treatment decreased proportions of Ki-67-positive cells and increased apoptosis in a dose-dependent manner. Rats treated with 100 mg/kg NP exhibited significantly increased mRNA expression of caspase-1, -2, -9, and -11, decreased caspase-8 and PCNA1 mRNA expression, downregulation of Bcl-2/Bax ratios and upregulation of Fas, FasL, and p53 at the protein and mRNA levels. Taken together, NP-induced apoptosis, hormonal deficiencies, and depletion of fructose potentially impairs spermatogenesis and sperm function. p53-independent Fas/FasL-Bax/Bcl-2 pathways may be involved in NP-induced oxidative stress-related apoptosis. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 739-753, 2017.

  13. Red photon treatment inhibits apoptosis via regulation of bcl-2 proteins and ROS levels, alleviating hypoxic-ischemic brain damage.

    PubMed

    Jiang, W; Chen, L; Zhang, X J; Chen, J; Li, X C; Hou, W S; Xiao, N

    2014-05-30

    Therapeutic options for hypoxic-ischemic brain damage (HIBD) are scarce and inefficient. Recently, many studies have demonstrated that red photon plays an important role in anti-inflammatory processes as well as apoptosis, the main trait of HIBD. In this study, we investigated whether red photon can protect from HIBD in SD rats and oxygen-glucose deprivation (OGD) in PC12 cells. Apoptosis, mitochondrial transmembrane potential (MMP), and reactive oxygen species (ROS) rates were assessed in PC12 cells. We found that 6-h irradiation resulted in decreased MMP, ROS and apoptosis rates, although these changes were reversible with prolonged irradiation. Importantly, these effects were sustained for 2-8h upon quenching of the red photon. Similar trends were observed for protein and mRNA expression of bax and bcl-2, with short-term irradiation (6h) inhibiting apoptosis in PC12 Cells. However, long-term (>6h) irradiation caused cell damage. In vivo experiments, bax mRNA and protein levels were reduced after 7days in HIBD model rats treated with red photon, in contrast to bcl-2. Furthermore, we found that bax and bcl-2 were mainly expressed in pyramidal cells of the hippocampus CA1 and CA3. Importantly, Morris Water Maze test results revealed an improvement in learning ability and spatial memory in rats after irradiation. Overall, our data showed that short-term irradiation with red photon in the acute phase inhibits the mitochondrial apoptotic pathway via regulation of bcl-2-related proteins and reduction of ROS levels, thereby decreasing apoptosis in nerve cells and improving the neurological prognosis of HIBD.

  14. Synthetic Antibodies Inhibit Bcl-2-associated X Protein (BAX) through Blockade of the N-terminal Activation Site*

    PubMed Central

    Uchime, Onyinyechukwu; Dai, Zhou; Biris, Nikolaos; Lee, David; Sidhu, Sachdev S.; Li, Sheng; Lai, Jonathan R.; Gavathiotis, Evripidis

    2016-01-01

    The BCL-2 protein family plays a critical role in regulating cellular commitment to mitochondrial apoptosis. Pro-apoptotic Bcl-2-associated X protein (BAX) is an executioner protein of the BCL-2 family that represents the gateway to mitochondrial apoptosis. Following cellular stresses that induce apoptosis, cytosolic BAX is activated and translocates to the mitochondria, where it inserts into the mitochondrial outer membrane to form a toxic pore. How the BAX activation pathway proceeds and how this may be inhibited is not yet completely understood. Here we describe synthetic antibody fragments (Fabs) as structural and biochemical probes to investigate the potential mechanisms of BAX regulation. These synthetic Fabs bind with high affinity to BAX and inhibit its activation by the BH3-only protein tBID (truncated Bcl2 interacting protein) in assays using liposomal membranes. Inhibition of BAX by a representative Fab, 3G11, prevented mitochondrial translocation of BAX and BAX-mediated cytochrome c release. Using NMR and hydrogen-deuterium exchange mass spectrometry, we showed that 3G11 forms a stoichiometric and stable complex without inducing a significant conformational change on monomeric and inactive BAX. We identified that the Fab-binding site on BAX involves residues of helices α1/α6 and the α1-α2 loop. Therefore, the inhibitory binding surface of 3G11 overlaps with the N-terminal activation site of BAX, suggesting a novel mechanism of BAX inhibition through direct binding to the BAX N-terminal activation site. The synthetic Fabs reported here reveal, as probes, novel mechanistic insights into BAX inhibition and provide a blueprint for developing inhibitors of BAX activation. PMID:26565029

  15. Reactive oxygen species mediate heat stress-induced apoptosis via ERK dephosphorylation and Bcl-2 ubiquitination in human umbilical vein endothelial cells.

    PubMed

    Li, Li; Tan, Hongping; Yang, Hong; Li, Feng; He, Xuan; Gu, Zhengtao; Zhao, Ming; Su, Lei

    2016-12-25

    Heat stress can induce the mitochondrial apoptotic pathway in HUVEC cells, indicating that apoptosis may be a prominent pathological feature of heat stroke, however, little is known about the precise mechani sms involved in it. In this study, we describe the apoptotic effect of intense heat stress on HUVEC cells and our investigation of its underlying mechanisms. Treatment of cells with intense heat stress induced production of reactive oxygen species (ROS) and a concomitant increase in activation of the mitochondrial apoptotic pathway. Furthermore, by over-expression of MnSOD and GPx in cells, we show that ROS, and especially superoxide, is the primary oxidative species induced by intense heat stress and responsible for cell death. In addition, we explored the mechanism by which superoxide regulates the apoptotic effect of intense heat stress, and found that it involved Bcl-2 down-regulation through ubiquitin - proteasomal degradation. Superoxide production also led to Bcl-2 dephosphorylation through inactivation of MAP kinase ERK1/2, which promoted Bcl-2 ubiquitination. Taken together, these findings describe a novel pathway downstream of heat stress-induced apoptosis in HUVEC cells, and provide new insight into the process of redox-mediated down-regulation of Bcl-2 and apoptosis induction. These results could be important in the understanding of pathogenesis of heat stroke and for the development of preventive and treatment measures, both of which are currently lacking.

  16. MYBL2 guides autophagy suppressor VDAC2 in the developing ovary to inhibit autophagy through a complex of VDAC2-BECN1-BCL2L1 in mammals.

    PubMed

    Yuan, Jia; Zhang, Ying; Sheng, Yue; Fu, Xiazhou; Cheng, Hanhua; Zhou, Rongjia

    2015-01-01

    Oogenesis is essential for female gamete production in mammals. The total number of ovarian follicles is determined early in life and production of ovarian oocytes is thought to stop during the lifetime. However, the molecular mechanisms underling oogenesis, particularly autophagy regulation in the ovary, remain largely unknown. Here, we reveal an important MYBL2-VDAC2-BECN1-BCL2L1 pathway linking autophagy suppression in the developing ovary. The transcription factors GATA1 and MYBL2 can bind to and activate the Vdac2 promoter. MYBL2 regulates the spatiotemporal expression of VDAC2 in the developing ovary. Strikingly, in the VDAC2 transgenic pigs (Sus scrofa/Ss), VDAC2 exerts its function by inhibiting autophagy in the ovary. In contrast, Vdac2 knockout promotes autophagy. Moreover, VDAC2-mediated autophagy suppression is dependent on its interactions with both BECN1 and BCL2L1 to stabilize the BECN1 and BCL2L1 complex, suggesting VDAC2 as an autophagy suppressor in the pathway. Our findings provide a functional connection among the VDAC2, MYBL2, the BECN1-BCL2L1 pathway and autophagy suppression in the developing ovary, which is implicated in improving female fecundity.

  17. Cooperation of bcl-2 and myc in the neoplastic transformation of normal rat liver epithelial cells is related to the down-regulation of gap junction-mediated intercellular communication.

    PubMed

    DeoCampo, N D; Wilson, M R; Trosko, J E

    2000-08-01

    The objectives of this study were to isolate several rat liver epithelial cell clones containing the human bcl-2 and myc/bcl-2 genes in order to study their potential cooperative effect on neoplastic transformation and gap junction-mediated intercellular communication (GJIC) and to test the hypothesis that the loss of GJIC leads to tumorigenesis. Using anchorage-independent growth as a surrogate marker for neoplastic transformation, we transfected both normal rat liver epithelial cells, WB-F344, and a WB-F344 cell line overexpressing v-myc with human bcl-2 cDNA. Those cell lines that only expressed v-myc or human bcl-2 were unable to form colonies in soft agar. However, those cell lines that overexpressed both v-myc and human bcl-2 showed varying ability to form colonies in soft agar, which did not correlate with their human bcl-2 expression level. In order to test if there was a correlation between cell line growth in soft agar and the ability to communicate through gap junctions, we performed scrape load dye transfer and fluorescence recovery after photobleaching assays. Our results show that v-myc and human bcl-2 can cooperate in the transformation of normal cells, but the degree to which the cells are transformed is dependent on the cells' ability to communicate through gap junctions.

  18. Metabolic reprogramming in cancer cells: glycolysis, glutaminolysis, and Bcl-2 proteins as novel therapeutic targets for cancer.

    PubMed

    Li, Chunxia; Zhang, Guifeng; Zhao, Lei; Ma, Zhijun; Chen, Hongbing

    2016-01-20

    Nearly a century ago, Otto Warburg made the ground-breaking observation that cancer cells, unlike normal cells, prefer a seemingly inefficient mechanism of glucose metabolism: aerobic glycolysis, a phenomenon now referred to as the Warburg effect. The finding that rapidly proliferating cancer cells favors incomplete metabolism of glucose, producing large amounts of lactate as opposed to synthesizing ATP to sustain cell growth, has confounded scientists for years. Further investigation into the metabolic phenotype of cancer has expanded our understanding of this puzzling conundrum, and has opened new avenues for the development of anti-cancer therapies. Enhanced glycolytic flux is now known to allow for increased synthesis of intermediates for sustaining anabolic pathways critical for cancer cell growth. Alongside the increase in glycolysis, cancer cells transform their mitochondria into synthesis machines supported by augmented glutaminolysis, supplying lipid production, amino acid synthesis, and the pentose phosphate pathways. Inhibition of several of the key enzymes involved in these pathways has been demonstrated to effectively obstruct cancer cell growth and multiplication, sensitizing them to apoptosis. The modulation of various regulatory proteins involved in metabolic processes is central to cancerous reprogramming of metabolism. The finding that members of one of the major protein families involved in cell death regulation also aberrantly regulated in cancers, the Bcl-2 family of proteins, are also critical mediators of metabolic pathways, provides strong evidence for the importance of the metabolic shift to cancer cell survival. Targeting the anti-apoptotic members of the Bcl-2 family of proteins is proving to be a successful way to selectively target cancer cells and induce apoptosis. Further understanding of how cancer cells modify metabolic regulation to increase channeling of substrates into biosynthesis will allow for the discovery of novel drug

  19. Bax/bcl-2: cellular modulator of apoptosis in feline skin and basal cell tumours.

    PubMed

    Madewell, B R; Gandour-Edwards, R; Edwards, B F; Matthews, K R; Griffey, S M

    2001-01-01

    Bcl-2 and bax are two members of the BCL-2 gene family that play a prominent role in the regulation of apoptosis. Bax and bcl-2 expression were examined immunohistochemically in normal (healthy) feline skin and in 24 benign feline cutaneous basal cell tumours. The tumours were also examined for cellular proliferation by measurement of reactivity for the proliferation marker Ki-67, and for apoptosis by in-situ labelling for fragmented DNA. Bcl-2 was detected in normal basal epithelium and in 23 of 24 basal cell tumours. Bax was detected in both basal and suprabasal epithelium, but in only seven of 24 tumours. For tumours that expressed both bax and bcl-2, the bax:bcl-2 ratio was low. Neither bax nor bcl-2 expression was detected in 14 feline cutaneous squamous cell carcinomas. Basal cell tumours showed modest cellular proliferation (median, 17.5% Ki-67- reactive cells), but few (less than 1%) apoptotic cells. The slow, indolent growth of feline cutaneous basal cells in these benign skin tumours may be a response, at least in part, to opposing regulatory expressions of bcl-2 and bax.

  20. ATMIN defines an NBS1-independent pathway of ATM signalling

    PubMed Central

    Kanu, Nnennaya; Behrens, Axel

    2007-01-01

    The checkpoint kinase ATM (ataxia telangiectasia mutated) transduces genomic stress signals to halt cell cycle progression and promote DNA repair in response to DNA damage. Here, we report the characterisation of an essential cofactor for ATM, ATMIN (ATM INteracting protein). ATMIN interacts with ATM through a C-terminal motif, which is also present in Nijmegen breakage syndrome (NBS)1. ATMIN and ATM colocalised in response to ATM activation by chloroquine and hypotonic stress, but not after induction of double-strand breaks by ionising radiation (IR). ATM/ATMIN complex disruption by IR was attenuated in cells with impaired NBS1 function, suggesting competition of NBS1 and ATMIN for ATM binding. ATMIN protein levels were reduced in ataxia telangiectasia cells and ATM protein levels were low in primary murine fibroblasts lacking ATMIN, indicating reciprocal stabilisation. Whereas phosphorylation of Smc1, Chk2 and p53 was normal after IR in ATMIN-deficient cells, basal ATM activity and ATM activation by hypotonic stress and inhibition of DNA replication was impaired. Thus, ATMIN defines a novel NBS1-independent pathway of ATM signalling. PMID:17525732

  1. Computationally designed high specificity inhibitors delineate the roles of BCL2 family proteins in cancer

    PubMed Central

    Berger, Stephanie; Procko, Erik; Margineantu, Daciana; Lee, Erinna F; Shen, Betty W; Zelter, Alex; Silva, Daniel-Adriano; Chawla, Kusum; Herold, Marco J; Garnier, Jean-Marc; Johnson, Richard; MacCoss, Michael J; Lessene, Guillaume; Davis, Trisha N; Stayton, Patrick S; Stoddard, Barry L; Fairlie, W Douglas; Hockenbery, David M; Baker, David

    2016-01-01

    Many cancers overexpress one or more of the six human pro-survival BCL2 family proteins to evade apoptosis. To determine which BCL2 protein or proteins block apoptosis in different cancers, we computationally designed three-helix bundle protein inhibitors specific for each BCL2 pro-survival protein. Following in vitro optimization, each inhibitor binds its target with high picomolar to low nanomolar affinity and at least 300-fold specificity. Expression of the designed inhibitors in human cancer cell lines revealed unique dependencies on BCL2 proteins for survival which could not be inferred from other BCL2 profiling methods. Our results show that designed inhibitors can be generated for each member of a closely-knit protein family to probe the importance of specific protein-protein interactions in complex biological processes. DOI: http://dx.doi.org/10.7554/eLife.20352.001 PMID:27805565

  2. Computationally designed high specificity inhibitors delineate the roles of BCL2 family proteins in cancer.

    PubMed

    Berger, Stephanie; Procko, Erik; Margineantu, Daciana; Lee, Erinna F; Shen, Betty W; Zelter, Alex; Silva, Daniel-Adriano; Chawla, Kusum; Herold, Marco J; Garnier, Jean-Marc; Johnson, Richard; MacCoss, Michael J; Lessene, Guillaume; Davis, Trisha N; Stayton, Patrick S; Stoddard, Barry L; Fairlie, W Douglas; Hockenbery, David M; Baker, David

    2016-11-02

    Many cancers overexpress one or more of the six human pro-survival BCL2 family proteins to evade apoptosis. To determine which BCL2 protein or proteins block apoptosis in different cancers, we computationally designed three-helix bundle protein inhibitors specific for each BCL2 pro-survival protein. Following in vitro optimization, each inhibitor binds its target with high picomolar to low nanomolar affinity and at least 300-fold specificity. Expression of the designed inhibitors in human cancer cell lines revealed unique dependencies on BCL2 proteins for survival which could not be inferred from other BCL2 profiling methods. Our results show that designed inhibitors can be generated for each member of a closely-knit protein family to probe the importance of specific protein-protein interactions in complex biological processes.

  3. A poxvirus Bcl-2-like gene family involved in regulation of host immune response: sequence similarity and evolutionary history

    PubMed Central

    2010-01-01

    Background Poxviruses evade the immune system of the host through the action of viral encoded inhibitors that block various signalling pathways. The exact number of viral inhibitors is not yet known. Several members of the vaccinia virus A46 and N1 families, with a Bcl-2-like structure, are involved in the regulation of the host innate immune response where they act non-redundantly at different levels of the Toll-like receptor signalling pathway. N1 also maintains an anti-apoptotic effect by acting similarly to cellular Bcl-2 proteins. Whether there are related families that could have similar functions is the main subject of this investigation. Results We describe the sequence similarity existing among poxvirus A46, N1, N2 and C1 protein families, which share a common domain of approximately 110-140 amino acids at their C-termini that spans the entire N1 sequence. Secondary structure and fold recognition predictions suggest that this domain presents an all-alpha-helical fold compatible with the Bcl-2-like structures of vaccinia virus proteins N1, A52, B15 and K7. We propose that these protein families should be merged into a single one. We describe the phylogenetic distribution of this family and reconstruct its evolutionary history, which indicates an extensive gene gain in ancestral viruses and a further stabilization of its gene content. Conclusions Based on the sequence/structure similarity, we propose that other members with unknown function, like vaccinia virus N2, C1, C6 and C16/B22, might have a similar role in the suppression of host immune response as A46, A52, B15 and K7, by antagonizing at different levels with the TLR signalling pathways. PMID:20230632

  4. Thymoquinone decreases F-actin polymerization and the proliferation of human multiple myeloma cells by suppressing STAT3 phosphorylation and Bcl2/Bcl-XL expression

    PubMed Central

    2011-01-01

    Background Thymoquinone (TQ), the major active component of the medicinal herb Nigella sativa Linn., has been described as a chemopreventive and chemotherapeutic compound. Methods In this study, we investigated the effect of TQ on survival, actin cytoskeletal reorganization, proliferation and signal transduction in multiple myeloma (MM) cells. Results We found that TQ induces growth arrest in both MDN and XG2 cells in a dose- and time-dependent manner. TQ also inhibited CXC ligand-12 (CXCL-12)-mediated actin polymerization and cellular proliferation, as shown by flow cytometry. The signal transducer and activator of transcription (STAT) and B-cell lymphoma-2 (Bcl-2) signaling pathways may play important roles in the malignant transformation of a number of human malignancies. The constitutive activation of the STAT3 and Bcl-2 pathways is frequently observed in several cancer cell lines, including MM cells. Using flow cytometry, we found that TQ markedly decreased STAT3 phosphorylation and Bcl-2 and Bcl-XL expression without modulating STAT5 phosphorylation in MM cells. Using western blotting, we confirmed the inhibitory effect of TQ on STAT3 phosphorylation and Bcl-2 and Bcl-XL expression. Conclusions Taken together, our data suggests that TQ could potentially be applied toward the treatment of MM and other malignancies. PMID:22177381

  5. The inhibition of PI3K and NFκB promoted curcumin-induced cell cycle arrest at G2/M via altering polyamine metabolism in Bcl-2 overexpressing MCF-7 breast cancer cells.

    PubMed

    Berrak, Özge; Akkoç, Yunus; Arısan, Elif Damla; Çoker-Gürkan, Ajda; Obakan-Yerlikaya, Pınar; Palavan-Ünsal, Narçin

    2016-02-01

    Bcl-2 protein has been contributed with number of genes which are involved in oncogenesis. Among the many targets of Bcl-2, NFκB have potential role in induction of cell cycle arrest. Curcumin has potential therapeutic effects against breast cancer through multiple signaling pathways. In this study, we investigated the role of curcumin in induction of cell cycle arrest via regulating of NFκB and polyamine biosynthesis in wt and Bcl-2+ MCF-7 cells. To examine the effect of curcumin on cell cycle regulatory proteins, PI3K/Akt, NFκB pathways and polyamine catabolism, we performed immunoblotting assay. In addition, cell cycle analysis was performed by flow cytometry. The results indicated that curcumin induced cell cycle arrest at G2/M phase by downregulation of cyclin B1 and Cdc2 and inhibited colony formation in MCF-7wt cells. However, Bcl-2 overexpression prevented the inhibition of cell cycle associated proteins after curcumin treatment. The combination of LY294002, PI3K inhibitor, and curcumin induced cell cycle arrest by decreasing CDK4, CDK2 and cyclin E2 in Bcl-2+ MCF-7 cells. Moreover, LY294002 further inhibited the phosphorylation of Akt in Bcl-2+ MCF-7 cells. Curcumin could suppress the nuclear transport of NFκB through decreasing the interaction of P-IκB-NFκB. The combination of wedelolactone, NFκB inhibitor, and curcumin acted different on SSAT expression in wt MCF-7 and Bcl-2+ MCF-7 cells. NFκB inhibition increased the SSAT after curcumin treatment in Bcl-2 overexpressed MCF-7 cells. Inhibition of NFκB activity as well as suppression of ROS generation with NAC resulted in the partial relief of cells from G2/M checkpoint after curcumin treatment in wt MCF-7 cells. In conclusion, the potential role of curcumin in induction of cell cycle arrest is related with NFκB-regulated polyamine biosynthesis.

  6. Effects of BCL-2 over-expression on B cells in transgenic rats and rat hybridomas.

    PubMed

    Iscache, Anne-Laure; Ménoret, Séverine; Tesson, Laurent; Rémy, Séverine; Usal, Claire; Pedros, Christophe; Saoudi, Abdelhadi; Buelow, Roland; Anegon, Ignacio

    2011-10-01

    The rat is an important biomedical experimental model that benefited from the recent development of new transgenic and knockout techniques. With the goal to optimize rat mAb production and to analyze the impact of Bcl-2 on B-cell development, we generated bcl-2 transgenic rats. Transgenic rats showed Bcl-2 over-expression in B cells, increased B cell numbers in lymphoid organs, elevated production of immunoglobulins (Igs) and prolonged B-cell survival in vitro. Transgenic rats remained healthy, reproduced normally and did not develop autoimmunity. Fusions with bcl-2 transgenic splenocytes did not result in increased hybridoma generation. A comparison of on- and off-rates of 39 mAbs generated with bcl-2 transgenic and wild-type animals revealed no significant differences. Over-expression of Bcl-2 in hybridomas did not change cell proliferation but resulted in increased Ig production. Bcl-2 transgenic rats will be a useful tool for the generation of rat mAbs, the analysis of B cells in different pathophysiological models, such as autoimmunity, cancer or organ transplantation, and the study of rat B-cell biology.

  7. Cell cycle progression dictates the requirement for BCL2 in natural killer cell survival.

    PubMed

    Viant, Charlotte; Guia, Sophie; Hennessy, Robert J; Rautela, Jai; Pham, Kim; Bernat, Claire; Goh, Wilford; Jiao, Yuhao; Delconte, Rebecca; Roger, Michael; Simon, Vanina; Souza-Fonseca-Guimaraes, Fernando; Grabow, Stephanie; Belz, Gabrielle T; Kile, Benjamin T; Strasser, Andreas; Gray, Daniel; Hodgkin, Phillip D; Beutler, Bruce; Vivier, Eric; Ugolini, Sophie; Huntington, Nicholas D

    2017-02-01

    Natural killer (NK) cells are innate lymphoid cells with antitumor functions. Using an N-ethyl-N-nitrosourea (ENU)-induced mutagenesis screen in mice, we identified a strain with an NK cell deficiency caused by a hypomorphic mutation in the Bcl2 (B cell lymphoma 2) gene. Analysis of these mice and the conditional deletion of Bcl2 in NK cells revealed a nonredundant intrinsic requirement for BCL2 in NK cell survival. In these mice, NK cells in cycle were protected against apoptosis, and NK cell counts were restored in inflammatory conditions, suggesting a redundant role for BCL2 in proliferating NK cells. Consistent with this, cycling NK cells expressed higher MCL1 (myeloid cell leukemia 1) levels in both control and BCL2-null mice. Finally, we showed that deletion of BIM restored survival in BCL2-deficient but not MCL1-deficient NK cells. Overall, these data demonstrate an essential role for the binding of BCL2 to BIM in the survival of noncycling NK cells. They also favor a model in which MCL1 is the dominant survival protein in proliferating NK cells.

  8. Restrained Terminal Differentiation and Sustained Stemness in Neonatal Skin by Ha-Ras and Bcl-2.

    PubMed

    Lee, Sangjun; Rodriguez-Villanueva, Julio; McDonnell, Timothy

    2017-03-01

    Nonmelanoma skin cancer is the most frequently diagnosed cancer in the United States. Deregulation of bcl-2 and ras family members is commonly observed in nonmelanoma skin cancer. It has been previously demonstrated that simultaneous bcl-2 and Ha-ras gene expression in keratinocytes results in resistance to cell death induced by ultraviolet radiation and enhanced multistep skin carcinogenesis. In this study, we aimed to elucidate the central roles of Ha-Ras and Bcl-2 in maintaining epidermal homeostasis. To assess the effect of deregulated Ha-Ras and Bcl-2 on skin differentiation, we have generated skin-specific transgenic mouse model constitutively expressing both oncogenic Ha-Ras and Bcl-2. Ectopic expression of Ha-Ras and Bcl-2 in newborn double transgenic epidermal keratinocytes induced abnormal epidermal differentiation accompanied by increased cell proliferation and suppressed apoptotic cell death, which resulted in thickened and wrinkled skin morphology in neonate skins. Expression of epidermal differentiation marker cytokeratin 1 was decreased. Expression of other differentiation markers loricrin and filaggrin was also decreased and delayed to be detected only in the upper stratum granulosum, whereas the proliferative markers cytokeratin 14 and cytokeratin 6, which are expressed in constitutively proliferative basal layer and stem cell niches such as hair follicles or neoplastic lesions, respectively, were highly expressed. The abnormal expression of epidermal cytokeratins suggests that Ha-Ras and Bcl-2 suppress the terminal differentiation and sustain the stem cell-like features in epidermal keratinocytes.

  9. Targeting BCL-2 to enhance vulnerability to therapy in estrogen receptor-positive breast cancer.

    PubMed

    Merino, D; Lok, S W; Visvader, J E; Lindeman, G J

    2016-04-14

    The last three decades have seen significant progress in our understanding of the role of the pro-survival protein BCL-2 and its family members in apoptosis and cancer. BCL-2 and other pro-survival family members including Mcl-1 and BCL-XL have been shown to have a key role in keeping pro-apoptotic 'effector' proteins BAK and BAX in check. They also neutralize a group of 'sensor' proteins (such as BIM), which are triggered by cytotoxic stimuli such as chemotherapy. BCL-2 proteins therefore have a central role as guardians against apoptosis, helping cancer cells to evade cell death. More recently, an increasing number of BH3 mimetics, which bind and neutralize BCL-2 and/or its pro-survival relatives, have been developed. The utility of targeting BCL-2 in hematological malignancies has become evident in early-phase studies, with remarkable clinical responses seen in heavily pretreated patients. As BCL-2 is overexpressed in ~75% of breast cancer, there has been growing interest in determining whether this new class of drug could show similar promise in breast cancer. This review summarizes our current understanding of the role of BCL-2 and its family members in mammary gland development and breast cancer, recent progress in the development of new BH3 mimetics as well as their potential for targeting estrogen receptor-positive breast cancer.

  10. S-Nitrosylation of Bcl-2 Negatively Affects Autophagy in Lung Epithelial Cells

    PubMed Central

    Wright, Clayton; Iyer, Anand Krishnan V.; Kulkarni, Yogesh; Azad, Neelam

    2015-01-01

    Autophagy is a catabolic cellular mechanism involving lysosomal degradation of unwanted cellular components. Interaction between Beclin-1 and Bcl-2 proteins is known to play a critical role in the initiation of autophagy. We report that malignantly transformed lung epithelial cells are resistant to autophagy and express lower basal levels of autophagic proteins, Beclin-1 and LC3-II as compared to non-tumorigenic cells. Additionally, increased levels of nitric oxide (NO) and Bcl-2 were observed in transformed cells. Nitric oxide was found to negatively regulate autophagy initiation and autophagic flux by nitrosylating Bcl-2 and stabilizing its interaction with Beclin-1, resulting in inhibition of Beclin-1 activity. An increase in the apoptotic initiator caspase-9 and the apoptosis and autophagy-associated kinase p38/MAPK in both cell types indicated possible autophagy–apoptosis crosstalk. Pre-treatments with ABT-737 (Bcl-2 inhibitor) and aminoguanidine (NO inhibitor), and transfection with a non-nitrosylable Bcl-2 cysteine double-mutant plasmid resulted in increased autophagic flux (LC3-II/p62 upregulation) corresponding with decreased S-nitrocysteine expression, thus corroborating the regulatory role of Bcl-2 S-nitrosylation in autophagy. In conclusion, our study reveals a novel mechanism of autophagy resistance via post-translational modification of Bcl-2 protein by NO, which may be critical in driving cellular tumorigenesis. PMID:26241894

  11. Multiple Bcl-2 family immunomodulators from vaccinia virus regulate MAPK/AP-1 activation.

    PubMed

    Torres, Alice A; Albarnaz, Jonas D; Bonjardim, Cláudio A; Smith, Geoffrey L

    2016-09-01

    Vaccinia virus (VACV) is a poxvirus and encodes many proteins that modify the host cell metabolism or inhibit the host response to infection. For instance, it is known that VACV infection can activate the mitogen-activated protein kinase (MAPK)/activator protein 1 (AP-1) pathway and inhibit activation of the pro-inflammatory transcription factor NF-κB. Since NF-κB and MAPK/AP-1 share common upstream activators we investigated whether six different VACV Bcl-2-like NF-κB inhibitors can also influence MAPK/AP-1 activation. Data presented show that proteins A52, B14 and K7 each contribute to AP-1 activation during VACV infection, and when expressed individually outwith infection. B14 induced the greatest stimulation of AP-1 and further investigation showed B14 activated mainly the MAPKs ERK (extracellular signal-regulated kinase) and JNK (Jun N-terminal kinase), and their substrate c-Jun (a component of AP-1). These data indicate that the same viral protein can have different effects on distinct signalling pathways, in blocking NF-κB activation whilst leading to MAPK/AP-1 activation.

  12. Oligomerization process of Bcl-2 associated X protein revealed from intermediate structures in solution.

    PubMed

    Shih, Orion; Yeh, Yi-Qi; Liao, Kuei-Fen; Sung, Tai-Ching; Chiang, Yun-Wei; Jeng, U-Ser

    2017-03-15

    Upon apoptotic stress, Bcl-2 associated X (BAX) protein undergoes conformational changes and oligomerizes, leading to the mitochondrial membrane permeabilization and cell death. While structures of the resultant oligomer have been extensively studied, little is known about the intermediates that describe the reaction pathway from the inactive monomers to activated oligomers. Here we characterize the intermediate structures of BAX using combined small-angle X-ray scattering (SAXS) with on-line gel-filtration and electron spin resonance (ESR). The intermediates, including monomers, dimers, and tetramers, are reconstructed via integrating the SAXS-envelopes and ESR-determined skeleton structures. The hence revealed structures suggest a linear oligomerization of BAX utilizing the extended dimers with the two flexible α6 chains protruded out as ditopic ligands. The results of molecular dynamics simulation also support the ditopic dimer conformation with mobile α6. The ditopic dimers could further wind into a helical rod structure with three dimers in one helical turn. Our results not only reveal the on-pathway intermediates, but also suggest a ditopic oligomerization mechanism that may bridge the observed intermediate structures in solution to the large BAX assemblies lately observed on mitochondria.

  13. Prognostic significance of the bcl-2 apoptotic family of proteins in primary and recurrent cervical cancer.

    PubMed Central

    Crawford, R. A.; Caldwell, C.; Iles, R. K.; Lowe, D.; Shepherd, J. H.; Chard, T.

    1998-01-01

    bcl-2 is one of a family of genes that control the apoptotic threshold of a cell. bcl-2 protein and its anti-apoptotic homologue, mcl-1, with the pro-apoptotic protein, bax, are thought to function by forming homo- and heterotypic dimers that then control the progression to apoptosis. p53 is also involved as a down-regulator of bcl-2 and a promoter of bax. To determine the effect of these apoptotic mechanisms, we used immunohistochemistry to determine the prognostic significance of the expression of bcl-2, mcl-1, bax and p53 in primary and recurrent cervical cancer. Tissues from 46 patients with primary cervical cancer and 28 women with recurrent carcinoma were stained for bcl-2, mcl-1, bax and p53. Kaplan-Meier survival analysis was performed using the log-rank test for differences between groups. In the primary disease group, positive staining for bcl-2 was associated with a better 5-year survival (bcl-2 +ve, 84% vs bcl-2 -ve, 53%, P = 0.03). Positive staining for p53 was associated with a survival disadvantage (p53 +ve, 4-year survival 38% vs p53 -ve, 4-year survival 78%, P = 0.02). mcl-1 and bax staining were not useful as prognostic indicators in primary disease. No marker was prognostic in recurrent disease. Positive bcl-2 staining defines a group of patients with primary disease with a good prognosis. p53, an activator of the bax promoter, identifies a group with a worse outcome. In recurrent disease, none of the markers reflected prognosis. PMID:9683295

  14. Immunohistochemical analysis of Mcl-1 and Bcl-2 proteins in normal and neoplastic lymph nodes.

    PubMed Central

    Krajewski, S.; Bodrug, S.; Gascoyne, R.; Berean, K.; Krajewska, M.; Reed, J. C.

    1994-01-01

    The Bcl-2 protein blocks programmed cell death and becomes overproduced in many follicular non-Hodgkin's lymphomas as the result of t(14; 18) translocations involving the Bcl-2 gene. Mcl-1 is a recently discovered gene whose encoded protein has significant homology with Bcl-2 but whose function remains unknown. In this study, we compared the in vivo patterns of Bcl-2 and Mcl-1 protein production in normal and neoplastic lymph node biopsies by immunohistochemical means using specific polyclonal antisera. Intracellular Mcl-1 immunoreactivity was located primarily in the cytosol in a punctate pattern and was also seen in association with the nuclear envelope in many cases, similar to the results obtained for Bcl-2, which resides in the outer mitochondrial membrane, nuclear envelope, and endoplasmic reticulum. In 4 of 4 reactive tonsils and 28 of 28 nodes with reactive follicular hyperplasia, reciprocal patterns of Bcl-2 and Mcl-1 protein expression were observed. Bcl-2 immunostaining was highest in mantle zone lymphocytes and absent from most germinal center cells, whereas Mcl-1 immunoreactivity was highest in germinal center lymphocytes and absent from mantle zone lymphocytes. Mcl-1 was also expressed in some interfollicular lymphocytes, particularly those that had the appearance of activated lymphocytes. Similar to the patterns of Bcl-2 and mcl-1 expression seen in reactive nodes, Mcl-1 protein was largely absent from the malignant cells in 2 of 2 mantle cell lymphomas, whereas strong Bcl-2 immunostaining was found in these cells. In contrast to normal nodes, however, the neoplastic follicles of t(14;18) containing follicular non-Hodgkin's lymphomas immunostained positively for both Bcl-2 and Mcl-1 in 24 of 27 cases. Intense immunostaining for Mcl-1 was also observed in Reed-Sternberg cells in 2 of 2 cases of Hodgkin's disease but Bcl-2 immunoreactivity was present at much lower levels. These findings demonstrate that the levels of Mcl-1 and Bcl-2 proteins are

  15. Metabolism of cysteine by cyteinesulfinate-independent pathway(s) in rat hepatocytes

    SciTech Connect

    Stipanuk, M.H.; De La Rosa, J.; Drake, M.R.

    1986-05-01

    The metabolism of cysteine (CYS) and that of cysteinesulfinate (CSA) were studied in freshly isolated hepatocytes from fed rats. In incubations of rat hepatocytes with either 1 or 25 mM CSA, over 90% of the /sup 14/CO/sub 2/ formed from (1-/sup 14/C)CSA could be accounted for by production of hypotaurine plus taurine. In similar incubations with 1 or 25 mM CYS, only 4% of /sup 14/CO/sub 2/ evolution from (1-/sup 14/C)CYS could be accounted for by production of hypotaurine plus taurine. Addition of unlabeled CSA inhibited recovery of label from (1-/sup 14/C)CYS as /sup 14/CO/sub 2/ by 33%. Metabolism of CYS and of CSA were affected differently by addition of ..cap alpha..-ketoglutarate, a cosubstrate for transamination, or of propargylglycine, an inhibitor of cystathionase activity. These data suggest that a substantial proportion of CYS is catabolized by CSA-independent pathways in the rat hepatocyte. Although addition of ..cap alpha..-ketoglutarate to incubations of hepatocytes with CSA resulted in a marked increase in CSA catabolism via the transamination pathway, addition of keto acids to incubation systems had little or no effect on production of any metabolite from CYS. Thus, CYS transamination does not appear to be a major pathway of CYS metabolism in the hepatocyte. Inhibition of cystathionase with propargylglycine reduced both /sup 14/CO/sub 2/ production from (1-/sup 14/C)CYS and ammonia plus urea nitrogen production from CYS by about 50%; CSA catabolism was not affected. Thus, cleavage of cyst(e)ine by cystathionase may be an important physiological pathway for CYS catabolism in the liver.

  16. High efficacy of the BCL-2 inhibitor ABT199 (venetoclax) in BCL-2 high-expressing neuroblastoma cell lines and xenografts and rational for combination with MCL-1 inhibition.

    PubMed

    Bate-Eya, Laurel T; den Hartog, Ilona J M; van der Ploeg, Ida; Schild, Linda; Koster, Jan; Santo, Evan E; Westerhout, Ellen M; Versteeg, Rogier; Caron, Huib N; Molenaar, Jan J; Dolman, M Emmy M

    2016-05-10

    The anti-apoptotic protein B cell lymphoma/leukaemia 2 (BCL-2) is highly expressed in neuroblastoma and plays an important role in oncogenesis. In this study, the selective BCL-2 inhibitor ABT199 was tested in a panel of neuroblastoma cell lines with diverse expression levels of BCL-2 and other BCL-2 family proteins. ABT199 caused apoptosis more potently in neuroblastoma cell lines expressing high BCL-2 and BIM/BCL-2 complex levels than low expressing cell lines. Effects on cell viability correlated with effects on BIM displacement from BCL-2 and cytochrome c release from the mitochondria. ABT199 treatment of mice with neuroblastoma tumors expressing high BCL-2 levels only resulted in growth inhibition, despite maximum BIM displacement from BCL-2 and the induction of a strong apoptotic response. We showed that neuroblastoma cells might survive ABT199 treatment due to its acute upregulation of the anti-apoptotic BCL-2 family protein myeloid cell leukaemia sequence 1 (MCL-1) and BIM sequestration by MCL-1. In vitro inhibition of MCL-1 sensitized neuroblastoma cell lines to ABT199, confirming the pivotal role of MCL-1 in ABT199 resistance. Our findings suggest that neuroblastoma patients with high BCL-2 and BIM/BCL-2 complex levels might benefit from combination treatment with ABT199 and compounds that inhibit MCL-1 expression.

  17. High efficacy of the BCL-2 inhibitor ABT199 (venetoclax) in BCL-2 high-expressing neuroblastoma cell lines and xenografts and rational for combination with MCL-1 inhibition

    PubMed Central

    Bate-Eya, Laurel T.; den Hartog, Ilona J.M.; van der Ploeg, Ida; Schild, Linda; Koster, Jan; Santo, Evan E.; Westerhout, Ellen M.; Versteeg, Rogier; Caron, Huib N.; Molenaar, Jan J.; Dolman, M. Emmy M.

    2016-01-01

    The anti-apoptotic protein B cell lymphoma/leukaemia 2 (BCL-2) is highly expressed in neuroblastoma and plays an important role in oncogenesis. In this study, the selective BCL-2 inhibitor ABT199 was tested in a panel of neuroblastoma cell lines with diverse expression levels of BCL-2 and other BCL-2 family proteins. ABT199 caused apoptosis more potently in neuroblastoma cell lines expressing high BCL-2 and BIM/BCL-2 complex levels than low expressing cell lines. Effects on cell viability correlated with effects on BIM displacement from BCL-2 and cytochrome c release from the mitochondria. ABT199 treatment of mice with neuroblastoma tumors expressing high BCL-2 levels only resulted in growth inhibition, despite maximum BIM displacement from BCL-2 and the induction of a strong apoptotic response. We showed that neuroblastoma cells might survive ABT199 treatment due to its acute upregulation of the anti-apoptotic BCL-2 family protein myeloid cell leukaemia sequence 1 (MCL-1) and BIM sequestration by MCL-1. In vitro inhibition of MCL-1 sensitized neuroblastoma cell lines to ABT199, confirming the pivotal role of MCL-1 in ABT199 resistance. Our findings suggest that neuroblastoma patients with high BCL-2 and BIM/BCL-2 complex levels might benefit from combination treatment with ABT199 and compounds that inhibit MCL-1 expression. PMID:27056887

  18. Regulation of Bcl-2 and Bcl-xL anti-apoptotic protein expression by nuclear receptor PXR in primary cultures of human and rat hepatocytes.

    PubMed

    Zucchini, Nathalie; de Sousa, Georges; Bailly-Maitre, Béatrice; Gugenheim, Jean; Bars, Rémi; Lemaire, Géraldine; Rahmani, Roger

    2005-08-15

    The pregnane X receptor (PXR) plays a major role in the protection of the body by regulating the genes involved in the metabolism and elimination of potentially toxic xeno- and endobiotics. We previously described that PXR activator dexamethasone protects hepatocytes from spontaneous apoptosis. We hypothesise a PXR-dependent co-regulation process between detoxication and programmed cell death. Using primary cultured human and rat hepatocytes, we investigated to determine if PXR is implicated in the regulation of Bcl-2 and Bcl-xL, two crucial apoptosis inhibitors. In the present study we demonstrated that the treatment of primary cultured hepatocytes with PXR agonists increased hepatocyte viability and protects them from staurosporine-induced apoptosis. The anti-apoptotic capacity of PXR activation was correlated with Bcl-2 and Bcl-xL induction at both the transcriptional and protein levels in man and rats, respectively. The inhibition of PXR expression by antisense oligonucleotide abolished PXR activators Bcl-xL induction. Accordingly, PXR overexpression in HepG2 cells led to bcl-2 induction upon clotrimazole treatment and protects cells against Fas-induced apoptosis. Our results demonstrate that PXR expression is required for Bcl-2 and Bcl-xL up-regulation upon PXR activators treatment in human and rat hepatocytes. They also suggest that PXR may protect the liver against chemicals by simultaneously regulating detoxication and the apoptotic pathway.

  19. Prognostic value of Bcl-2 and Bax tumor cell expression in patients with non muscle-invasive bladder cancer receiving bacillus Calmette-Guerin immunotherapy.

    PubMed

    Ajili, Faouzia; Kaabi, Belhassen; Darouiche, Amine; Tounsi, Haifa; Kourda, Nadia; Chebil, Mohamed; Manai, Mohamed; Boubaker, Samir

    2012-02-01

    Apoptosis is the distinctive form of programmed cell death that complements cell proliferation in maintaining normal tissue homeostasis. The significance of constitutive apoptosis in the recurrence of Non Muscle Invasive Bladder Cancer has yet to be investigated. The aim of this study is to investigate the prognostic significance of Bax and Bcl-2 in terms of recurrence after BCG immunotherapy. Immunohistochemical analysis was performed on frozen biopsies to evaluate bcl-2 and Bax proteins expression in 28 cases of NMIBC. All patients with confirmed NMIBC were treated with intravesical BCG-immunotherapy. The follow up was performed for 26 months. The correlation between clinicopathological, immunohistochemical data and the response to BCG therapy was performed. Univariate analysis showed that, PT1 stage, High grade and Bax expression increased significantly the risk of recurrence (P = 0.015, P = 0.015 and P= 0.034 respectively). In addition, multivariate analysis selected the model involving stage, age, Bax and Bcl-2 expression as the best independent variables of recurrence. In conclusion, the expression of Bcl-2 and Bax in NMIBC could have a prognostic value in assessing the risk of recurrence after BCG immunotherapy. These findings require further investigations on larger cohort in order to ascertain new molecular markers of the response to BCG immunotherapy.

  20. Enforced BCL2 expression in B-lymphoid cells prolongs antibody responses and elicits autoimmune disease.

    PubMed Central

    Strasser, A; Whittingham, S; Vaux, D L; Bath, M L; Adams, J M; Cory, S; Harris, A W

    1991-01-01

    The biological functions of the BCL2 gene were investigated in transgenic mice harboring human BCL2 cDNA under the control of an immunoglobulin heavy chain enhancer (E mu). Mice of a representative transgenic strain, E mu-bcl-2-22, had a great excess of B lymphocytes, immunoglobulin-secreting cells, and serum immunoglobulins, attributable to increased longevity of B-lineage cells. Pre-B and plasma cells as well as B cells exhibited prolonged survival in culture. Immunized animals produced an amplified and protracted antibody response. Within the first year of life, most mice spontaneously produced antibodies to nuclear antigens, and 60% developed kidney disease, diagnosed as immune complex glomerulonephritis. Thus E mu-bcl-2-22 mice constitute a transgenic model for a systemic autoimmune disease resembling the human disorder systemic lupus erythematosus. Images PMID:1924327

  1. Bcl2 is not required for the development and maintenance of leukemia stem cells in mice

    PubMed Central

    González-Herrero, Inés; Vicente-Dueñas, Carolina; Orfao, Alberto; Flores, Teresa; Jiménez, Rafael; Cobaleda, César; Sánchez-García, Isidro

    2010-01-01

    The existence of leukemia stem cells (LSCs) responsible for tumor maintenance has been firmly established. Therefore, therapeutic targeting of these LSCs may have a profound impact on cancer eradication. The anti-apoptotic protein Bcl2 has been proposed as a therapeutic target, but its role in LSC biology has not been investigated. In order to understand the role of Bcl2 in LSC generation and maintenance, we have taken advantage of our Sca1-BCRABLp210 mouse model of human chronic myeloid leukemia and bcl2 gene-targeted mice. This study provides genetic evidence that the inhibition of Bcl2 is not critical for the generation, selection or maintenance of the tumor initiating and maintaining cells in mice. PMID:20299524

  2. Bcl-2 gene therapy prevents aminoglycoside-induced degeneration of auditory and vestibular hair cells.

    PubMed

    Pfannenstiel, Susanna C; Praetorius, Mark; Plinkert, Peter K; Brough, Douglas E; Staecker, Hinrich

    2009-01-01

    To evaluate the protective effects of bcl-2, we have developed an in vivo model of gentamicin ototoxicity in C57BL/6 mice using intratympanic delivery of gentamicin. Hair cell survival was evaluated using myosin VIIa immunohistochemistry, cytocochleogram and auditory brainstem response (ABR) testing. At 10 days after gentamicin application, a consistent loss of outer hair cells was seen. Mice were pretreated with an adenovector expressing human bcl-2 (Ad.11D.bcl-2) or a control vector (Ad.11D). Seventy-two hours after vector delivery mice were treated with intratympanic gentamicin and evaluated at 10 days after ototoxin delivery. Pretreatment with Ad.11D.bcl-2 resulted in morphologic protection of hair cells and preservation of hearing thresholds measured by ABR.

  3. A Potent and Highly Efficacious Bcl-2/Bcl-xL Inhibitor

    PubMed Central

    McEachern, Donna; Yang, Chao-Yie; Meagher, Jennifer; Stuckey, Jeanne; Wang, Shaomeng

    2013-01-01

    Our previously reported Bcl-2/Bcl-xL inhibitor, 4, effectively inhibited tumor growth but failed to achieve complete regression in vivo. We have now performed extensive modifications on its pyrrole core structure, which has culminated in the discovery of 32 (BM-1074). Compound 32 binds to Bcl-2 and Bcl-xL proteins with Ki values of < 1 nM and inhibits cancer cell growth with IC50 values of 1-2 nM in four small-cell lung cancer cell lines sensitive to potent and specific Bcl-2/Bcl-xL inhibitors. Compound 32 is capable of achieving rapid, complete and durable tumor regression in vivo at a well-tolerated dose-schedule. Compound 32 is the most potent and efficacious Bcl-2/Bcl-xL inhibitor reported to date. PMID:23448298

  4. Expression of Bcl-2 and Bax protein in normal pineal gland in children and young adult.

    PubMed

    Marcol, Wiesław; Kotulska, Katarzyna; Larysz-Brysz, Magdalena; Malinowska-Kołodziej, Izabela; Mandera, Marek; Lewin-Kowalik, Joanna

    2006-01-01

    The Bcl family contains both pro and antiapoptotic proteins participating in the regulation of neuronal cell death in several pathological conditions. However, very little is known about physiological profiles of Bcl-2/Bax expression in normal brain. In this study, we examined expression profile of Bcl-2 and Bax proteins in normal pineal gland in children. The material for analysis was obtained by biopsy of pineal parenchyma during surgery of pineal cysts. All specimens were labeled immunohistochemically and analyzed by means of confocal laser scanning microscope. We found only few Bcl-2 expressing (0.7%) and no Bax-immunopositive (0.0%) pinealocytes. Bcl-2-positive cells were mature neurons, neither young ones nor glia.

  5. Regulatory effect of Bcl-2 in ultraviolet radiation-induced apoptosis of the mouse crystalline lens

    PubMed Central

    DONG, YUCHEN; ZHENG, YAJUAN; XIAO, JUN; ZHU, CHAO; ZHAO, MEISHENG

    2016-01-01

    The aim of the present study was to analyze the role of Bcl-2 during the process of apoptosis in the mouse crystalline lens. In total, 12 normal mice served as the control group and 12 Bcl-2 knockout (K.O) mice served as the experimental group. The mouse crystalline lens was sampled for the detection of Bcl-2 and caspase-3 expression following exposure to ultraviolet (UV) radiation. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to determine Bcl-2 expression in the groups of normal mice receiving UV radiation or not receiving UV radiation. Samples of the murine crystalline lens were microscopically harvested and analyzed using western blotting. Apoptosis was detected using terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay. Furthermore, caspase 3 activity was examined using enzyme-linked immunosorbent assay kits, and RT-qPCR was used to analyze caspase-3 expression levels. The results of the present study demonstrated that there was no statistically significant difference in the level of Bcl-2 gene transcription between the two groups. In addition, UV radiation did not change the macrostructure of the crystalline lens in the group of normal mice or the group of Bcl-2 K.O mice. The results of the TUNEL assay indicated that the normal-UV group exhibited a more significant apoptosis level compared with the Bcl-2 K.O-UV group. Furthermore, the mRNA expression level of caspase-3 in the normal-UV group was significantly higher compared with the normal-nonUV group (P<0.05), while the levels in the Bcl-2 K.O-UV group were significantly higher compared with the Bcl-2 K.O and normal-nonUV groups (P<0.05). In addition, the mRNA expression level of caspase-3 was significantly higher in the normal-UV, as compared with the Bcl-2 K.O-UV group (P<0.05), and the variation trends in caspase-3 activity were consistent. In conclusion, the results of the present study demonstrated that Bcl-2 may have an important role in the

  6. Prognostic Influence of BCL2 on Molecular Subtypes of Breast Cancer

    PubMed Central

    Han, Wonshik; Kim, Jongjin; Moon, Hyeong-Gon; Oh, Sohee; Song, Yun Seon; Kim, Young A; Chang, Mee Soo; Noh, Dong-Young

    2017-01-01

    Purpose We aimed to reveal the prognostic influence of B-cell CLL/lymphoma 2 (BCL2) on molecular subtypes of breast cancer. Methods We analyzed 9,468 patients with primary breast cancer. We classified molecular subtypes according to the National Comprehensive Cancer Network (NCCN) and St. Gallen guidelines, mainly on the basis of the expression of hormonal receptor (HR), human epidermal growth factor receptor 2 (HER2), and Ki-67. Results Regarding NCCN classification, BCL2 was a strong favorable prognostic factor in the HR(+)/HER2(–) subtype (p<0.001) and a marginally significant favorable prognosticator in the HR(+)/HER2(+) subtype (p=0.046). BCL2 had no prognostic impact on HR(–)/HER2(+) and HR(–)/HER2(–) subtypes. In relation to St. Gallen classification, BCL2 was a strong favorable prognosticator in luminal A and luminal B/HER2(–) subtypes (both p<0.001). BCL2 was a marginally significant prognosticator in the luminal B/HER2(+) subtype (p=0.046), and it was not a significant prognosticator in HER2 or triple negative (TN) subtypes. The prognostic effect of BCL2 was proportional to the stage of breast cancer in HR(+)/HER2(–), HR(+)/HER2(+), and HR(–)/HER2(–) subtypes, but not in HR(–)/HER2(+) subtype. BCL2 was not a prognostic factor in TN breast cancer regardless of epidermal growth factor receptor expression. Conclusion The prognostic influence of BCL2 was different across molecular subtypes of breast cancer, and it was largely dependent on HR, HER2, Ki-67, and the stage of cancer. BCL2 had a strong favorable prognostic impact only in HR(+)/HER2(–) or luminal A and luminal B/HER2(–) subtypes, particularly in advanced stages. Further investigations are needed to verify the prognostic influence of BCL2 on molecular subtypes of breast cancer and to develop clinical applications for prognostication using BCL2. PMID:28382095

  7. Synergistic killing of human small cell lung cancer cells by the Bcl-2-inositol 1,4,5-trisphosphate receptor disruptor BIRD-2 and the BH3-mimetic ABT-263

    PubMed Central

    Greenberg, E F; McColl, K S; Zhong, F; Wildey, G; Dowlati, A; Distelhorst, C W

    2015-01-01

    Small cell lung cancer (SCLC) has an annual mortality approaching that of breast and prostate cancer. Although sensitive to initial chemotherapy, SCLC rapidly develops resistance, leading to less effective second-line therapies. SCLC cells often overexpress Bcl-2, which protects cells from apoptosis both by sequestering pro-apoptotic family members and by modulating inositol 1,4,5-trisphosphate receptor (IP3R)-mediated calcium signaling. BH3-mimetic agents such as ABT-263 disrupt the former activity but have limited activity in SCLC patients. Here we report for the first time that Bcl-2-IP3 receptor disruptor-2 (BIRD-2), a decoy peptide that binds to the BH4 domain of Bcl-2 and prevents Bcl-2 interaction with IP3Rs, induces cell death in a wide range of SCLC lines, including ABT-263-resistant lines. BIRD-2-induced death of SCLC cells appears to be a form of caspase-independent apoptosis mediated by calpain activation. By targeting different regions of the Bcl-2 protein and different mechanisms of action, BIRD-2 and ABT-263 induce cell death synergistically. Based on these findings, we propose that targeting the Bcl-2–IP3R interaction be pursued as a novel therapeutic strategy for SCLC, either by developing BIRD-2 itself as a therapeutic agent or by developing small-molecule inhibitors that mimic BIRD-2. PMID:26720343

  8. Expression of COX-2 and Bcl-2 in primary fallopian tube carcinoma: correlations with clinicopathologic features.

    PubMed

    Wang, Fang; Sun, Guo-Ping; Zou, Yan-Feng; Wu, Qiang; Wu, Hong-Yang; Wu, Ji-Feng; Zhou, Jia-De; Chen, Ke; Zhang, Xiu-Shan

    2011-01-01

    The aim of this study was to evaluate the expression of COX-2 and Bcl-2 in primary fallopian tube carcinoma (PFTC), as well as their correlations with clinicopathologic features. We studied a cohort of 33 patients with a pathological diagnosis of PFTC. Thirty normal tubal tissues used for controls were obtained from patients diagnosed with uterine myomas. Expression analysis for COX-2 and Bcl-2 was performed using the immunohistochemical technique. The rate of preoperative diagnosis was 18.2%. With a median survival of 61.0 months (95% CI: 43.2 to 78.8 months), the estimated five-year overall survival rate in the 33 patients was 39.0%. Increased expression of COX-2 and Bcl-2 was observed in tumor specimens compared to normal controls (p = 0.026; p = 0.003). The expression rate of COX-2 in node-positive tumors was significantly higher than that of node-negative tumors (p = 0.024). Moreover, the expression rate of COX-2 was statistically significantly higher in patients with infiltration through the serosa (p = 0.019). Positive significant associations were observed between Bcl-2 staining index and FIGO stage (p = 0.015), and between Bcl-2 staining and lymph node metastasis (p = 0.010). There was a significant correlation between COX-2 expression and Bcl-2 staining index (r = 0.517, p = 0.002). We conclude that COX-2 and Bcl-2 may potentially be useful prognostic markers for PFTC. The exact molecular mechanism for correlations between COX-2 and Bcl-2 remains to be elucidated.

  9. Cantharidin inhibits cell proliferation and promotes apoptosis in tongue squamous cell carcinoma through suppression of miR-214 and regulation of p53 and Bcl-2/Bax.

    PubMed

    Tian, Xiaoguang; Zeng, Guang; Li, Xi; Wu, Zizhong; Wang, Lei

    2015-06-01

    Cantharidin, a type of terpenoid, is a chemical compount secreted by the blister beetle or Mylabris phelarata pallas of the Meloidae family. Cantharidin is known to have good antitumor activity. The present study aimed to investigate the anticancer effect of cantharidin and its possible underlying mechanism using tongue squamous cell carcinoma (TSCC) TCA8113 cells. TCA8113 cells were treated with various concentrations of cantharidin, and the cell viability and cytotoxicity were assessed using MTT and LDH assays, respectively. Flow cytometry was conducted to examine cell apoptosis and colorimetric protease assay was performed to analyze caspase-9/3 activities in TCA8113 cells. qPCR and western blot analysis were used to investigate microRNA-214 (miR-214) expression, as well as the expression of p53, Bcl-2 and Bax proteins in TCA8113 cells. miR-214 and anti-miR-214 were transfected with mimics to examine whether miR-214 expression regulated the anticancer effect of cantharidin on TCA8113 cells and p53, Bcl-2 and Bax protein expression. The anticancer effect of cantharidin significantly inhibited cell proliferation and increased cytotoxicity of TSCC Tca8113 cells in a dose- and time-dependent manner. In addition, cantharidin induced cell apoptosis and activated caspase-9/3 activities of TSCC Tca8113 cells. Cantharidin markedly weakened miR-214 expression level, activated p53 protein expression, and suppressed the Bcl-2/Bax signaling pathway in Tca8113 cells. Downregulation of miR-214 increased p53 protein expression and decreased the Bcl-2/Bax signaling pathway of TSCC Tca8113 cells. However, the overexpression of miR-214 reduced the anticancer effect of cantharidin on the proliferation and apoptosis of TSCC Tca8113 cells, inhibited p53 protein expression, and increased the Bcl-2/Bax signaling pathway. The results suggested that cantharidin is a potential anticancer drug that can be used to regulate the proliferation and apoptosis of human TSCC Tca8113 cells

  10. IRBIT controls apoptosis by interacting with the Bcl-2 homolog, Bcl2l10, and by promoting ER-mitochondria contact

    PubMed Central

    Bonneau, Benjamin; Ando, Hideaki; Kawaai, Katsuhiro; Hirose, Matsumi; Takahashi-Iwanaga, Hiromi; Mikoshiba, Katsuhiko

    2016-01-01

    IRBIT is a molecule that interacts with the inositol 1,4,5-trisphosphate (IP3)-binding pocket of the IP3 receptor (IP3R), whereas the antiapoptotic protein, Bcl2l10, binds to another part of the IP3-binding domain. Here we show that Bcl2l10 and IRBIT interact and exert an additive inhibition of IP3R in the physiological state. Moreover, we found that these proteins associate in a complex in mitochondria-associated membranes (MAMs) and that their interplay is involved in apoptosis regulation. MAMs are a hotspot for Ca2+ transfer between endoplasmic reticulum (ER) and mitochondria, and massive Ca2+ release through IP3R in mitochondria induces cell death. We found that upon apoptotic stress, IRBIT is dephosphorylated, becoming an inhibitor of Bcl2l10. Moreover, IRBIT promotes ER mitochondria contact. Our results suggest that by inhibiting Bcl2l10 activity and promoting contact between ER and mitochondria, IRBIT facilitates massive Ca2+ transfer to mitochondria and promotes apoptosis. This work then describes IRBIT as a new regulator of cell death. DOI: http://dx.doi.org/10.7554/eLife.19896.001 PMID:27995898

  11. Methylation of CpG sites in BCL2 major breakpoint region and the increase of BCL2/JH translocation with aging.

    PubMed

    Martin-Guerrero, Idoia; de Prado, Elena; Ardanaz, Maite; Martin-Arruti, Maialen; Garcia-Orad, Cristina; Guerra, Isabel; Ruiz, Irune; Zabalza, Iñaki; Garcia-Orad, Africa

    2015-10-01

    The BCL2 breakage mechanism has been shown to be highly dependent on DNA methylation at the major breakpoint region (MBR) CpG sites. We recently described an increased frequency of BCL2/ JH translocation with aging. It is known that methylation levels change with aging. The present study aimed to determine whether methylation alterations at CpG sites of BCL2 MBR were the cause of increased breakages with aging. We analyzed the methylation levels of three CpG sites on the region by pyrosequencing and studied if methylation levels and/or polymorphisms affecting CpG sites were associated with an increase of translocations. We observed that although the methylation levels of MBR CpG sites were higher in individuals with BCL2/JH translocation, in contrast to our expectations, these levels decreased with the age. Moreover, we show that polymorphisms at those CpG sites leading to absence of methylation seem to be a protective factor for the apparition of translocations.

  12. Oestrogen signalling inhibits invasive phenotype by repressing RelB and its target BCL2.

    PubMed

    Wang, Xiaobo; Belguise, Karine; Kersual, Nathalie; Kirsch, Kathrin H; Mineva, Nora D; Galtier, Florence; Chalbos, Dany; Sonenshein, Gail E

    2007-04-01

    Aberrant constitutive expression of c-Rel, p65 and p50 NF-kappaB subunits has been reported in over 90% of breast cancers. Recently, we characterized a de novo RelB NF-kappaB subunit synthesis pathway, induced by the cytomegalovirus (CMV) IE1 protein, in which binding of p50-p65 NF-kappaB and c-Jun-Fra-2 AP-1 complexes to the RELB promoter work in synergy to potently activate transcription. Although RelB complexes were observed in mouse mammary tumours induced by either ectopic c-Rel expression or carcinogen exposure, little is known about RelB in human breast disease. Here, we demonstrate constitutive de novo RelB synthesis is selectively active in invasive oestrogen receptor alpha (ERalpha)-negative breast cancer cells. ERalpha signalling reduced levels of functional NF-kappaB and Fra-2 AP-1 and inhibited de novo RelB synthesis, leading to an inverse correlation between RELB and ERalpha gene expression in human breast cancer tissues and cell lines. Induction of Bcl-2 by RelB promoted the more invasive phenotype of ERalpha-negative cancer cells. Thus, inhibition of de novo RelB synthesis represents a new mechanism whereby ERalpha controls epithelial to mesenchymal transition (EMT).

  13. Oestrogen signalling inhibits invasive phenotype by repressing RelB and its target BCL2

    PubMed Central

    Wang, Xiaobo; Belguise, Karine; Kersual, Nathalie; Kirsch, Kathrin H.; Mineva, Nora D.; Galtier, Florence; Chalbos, Dany; Sonenshein, Gail E.

    2007-01-01

    Aberrant constitutive expression of c-Rel, p65 and p50 NF-κB subunits has been reported in over 90% of breast cancers1,2. Recently, we characterized a de novo RelB NF-κB subunit synthesis pathway, induced by the cytomegalovirus (CMV) IE1 protein, in which binding of p50/p65 NF-κB and c-Jun/Fra-2 AP-1 complexes to the RELB promoter work in synergy to potently activate transcription3. While RelB complexes were observed in mouse mammary tumors induced by either ectopic c-Rel expression4 or carcinogen exposure5, little is known about RelB in human breast disease. Here, we demonstrate constitutive de novo RelB synthesis is selectively active in invasive estrogen receptor (ER)α negative breast cancer cells. ERα signaling reduced levels of functional NF-κB and Fra-2 AP-1 and inhibited de novo RelB synthesis, leading to an inverse correlation between RELB and ERα gene expression in human breast cancer tissues and cell lines. Induction of Bcl-2 by RelB promoted the more invasive phenotype of ERα negative cancer cells. Thus, inhibition of de novo RelB synthesis represents a new mechanism whereby ERα controls epithelial to mesenchymal transition (EMT). PMID:17369819

  14. Oxidative stress-mediated down-regulation of bcl-2 promoter in hippocampal neurons.

    PubMed

    Pugazhenthi, Subbiah; Nesterova, Albina; Jambal, Purevsuren; Audesirk, Gerald; Kern, Marcey; Cabell, Leigh; Eves, Eva; Rosner, Marsha R; Boxer, Linda M; Reusch, Jane E-B

    2003-03-01

    Generation of oxidative stress/reactive oxygen species (ROS) is one of the causes of neuronal apoptosis. We have examined the effects of ROS at the transcriptional level in an immortalized hippocampal neuronal cell line (H19-7) and in rat primary hippocampal neurons. Treatment of H19-7 cells with hydrogen peroxide (150 micro m) resulted in a 40% decrease in Bcl-2 protein and a parallel decrease in bcl-2 mRNA levels. H19-7 cells overexpressing bcl-2 were found to be resistant to ROS-induced apoptosis. We had previously shown that bcl-2 promoter activity is positively regulated by the transcription factor cyclic AMP response element binding protein (CREB) in neurons. In the present study, we demonstrate that ROS decreases the activity of luciferase reporter gene driven by a cyclic AMP response element site containing bcl-2 promoter. Exposure of neurons to ROS for 6 h resulted in basal and fibroblast growth factor-2-stimulated phosphorylation/activation of CREB. Chronic 24 h treatment with ROS led to a significant (p < 0.01) decrease in CREB protein and CREB mRNA levels. Adenoviral overexpression of wild type CREB in H19-7 cells resulted in significant (p < 0.01) protection against ROS-induced apoptosis through up-regulation of Bcl-2 expression whereas dominant negative CREB exaggerated the injury. These findings demonstrate that loss of CREB function contributes to oxidative stress-induced neuronal dysfunction.

  15. Inducible functional expression of Bcl-2 in human astrocytes derived from NTera-2 cells.

    PubMed

    Ozdener, Hakan

    2007-01-15

    Astrocytes provide structural support for neurons and may also play important roles in both neuroprotection and neurodegeneration. We, here report that human astrocytes derived from on NTera-2 (NT2) cell line expressing a functional anti-apoptotic protein bcl-2 under the control of a tetracycline responsive promoter using the Tet-On and Tet-Off expression systems. NT2 cells were transfected with the Tet On or Tet Off vectors followed by pTRE carrying human bcl-2. Drug resistant cells were differentiated into astrocytes under retinoic acid exposure. These astrocyte lines were found to express astrocyte specific markers such glial fibrillary acidic protein and chemokine receptors (CCR5, CXCR4) but not CCR3 and CD4. Furthermore, NT2 astrocytes expressing bcl-2 showed rapid response to doxycycline presence in the Tet On and Tet off system. The inducible expression of bcl-2 was found to be tightly regulated by doxycycline concentration in the NT2 astrocytes. We also showed that the induction of bcl-2 expression prevented NT2 astrocytes from camptothecin-induced cellular damage. These results indicate that this system may be useful for the study of specific effects of bcl-2 gene expression on astrocyte function(s) and cellular damage.

  16. BCL2-BH4 antagonist BDA-366 suppresses human myeloma growth

    PubMed Central

    Deng, Jiusheng; Park, Dongkyoo; Wang, Mengchang; Nooka, Ajay; Deng, Qiaoya; Matulis, Shannon; Kaufman, Jonathan; Lonial, Sagar; Boise, Lawrence H.; Galipeau, Jacques; Deng, Xingming

    2016-01-01

    Multiple myeloma (MM) is a heterogeneous plasma cell malignancy and remains incurable. B-cell lymphoma-2 (BCL2) protein correlates with the survival and the drug resistance of myeloma cells. BH3 mimetics have been developed to disrupt the binding between BCL2 and its pro-apoptotic BCL2 family partners for the treatment of MM, but with limited therapeutic efficacy. We recently identified a small molecule BDA-366 as a BCL2 BH4 domain antagonist, converting it from an anti-apoptotic into a pro-apoptotic molecule. In this study, we demonstrated that BDA-366 induces robust apoptosis in MM cell lines and primary MM cells by inducing BCL2 conformational change. Delivery of BDA-366 substantially suppressed the growth of human MM xenografts in NOD-scid/IL2Rγnull mice, without significant cytotoxic effects on normal hematopoietic cells or body weight. Thus, BDA-366 functions as a novel BH4-based BCL2 inhibitor and offers an entirely new tool for MM therapy. PMID:27049723

  17. Bcl-2 Inhibits the Innate Immune Response during Early Pathogenesis of Murine Congenital Muscular Dystrophy

    PubMed Central

    Jeudy, Sheila; Wardrop, Katherine E.; Alessi, Amy; Dominov, Janice A.

    2011-01-01

    Laminin α2 (LAMA2)-deficient congenital muscular dystrophy is a severe, early-onset disease caused by abnormal levels of laminin 211 in the basal lamina leading to muscle weakness, transient inflammation, muscle degeneration and impaired mobility. In a Lama2-deficient mouse model for this disease, animal survival is improved by muscle-specific expression of the apoptosis inhibitor Bcl-2, conferred by a MyoD-hBcl-2 transgene. Here we investigated early disease stages in this model to determine initial pathological events and effects of Bcl-2 on their progression. Using quantitative immunohistological and mRNA analyses we show that inflammation occurs very early in Lama2-deficient muscle, some aspects of which are reduced or delayed by the MyoD-hBcl-2 transgene. mRNAs for innate immune response regulators, including multiple Toll-like receptors (TLRs) and the inflammasome component NLRP3, are elevated in diseased muscle compared with age-matched controls expressing Lama2. MyoD-hBcl-2 inhibits induction of TLR4, TLR6, TLR7, TLR8 and TLR9 in Lama2-deficient muscle compared with non-transgenic controls, and leads to reduced infiltration of eosinophils, which are key death effector cells. This congenital disease model provides a new paradigm for investigating cell death mechanisms during early stages of pathogenesis, demonstrating that interactions exist between Bcl-2, a multifunctional regulator of cell survival, and the innate immune response. PMID:21850221

  18. BCL-2 inhibition with ABT-737 prolongs survival in an NRAS/BCL-2 mouse model of AML by targeting primitive LSK and progenitor cells

    PubMed Central

    Beurlet, Stephanie; Omidvar, Nader; Gorombei, Petra; Krief, Patricia; Le Pogam, Carole; Setterblad, Niclas; de la Grange, Pierre; Leboeuf, Christophe; Janin, Anne; Noguera, Maria-Elena; Hervatin, Florence; Sarda-Mantel, Laure; Konopleva, Marina; Andreeff, Michael; Tu, Andrea W.; Fan, Alice C.; Felsher, Dean W.; Whetton, Anthony; Pla, Marika; West, Robert; Fenaux, Pierre; Chomienne, Christine

    2013-01-01

    Myelodysplastic syndrome (MDS) transforms into an acute myelogenous leukemia (AML) with associated increased bone marrow (BM) blast infiltration. Using a transgenic mouse model, MRP8[NRASD12/hBCL-2], in which the NRAS:BCL-2 complex at the mitochondria induces MDS progressing to AML with dysplastic features, we studied the therapeutic potential of a BCL-2 homology domain 3 mimetic inhibitor, ABT-737. Treatment significantly extended lifespan, increased survival of lethally irradiated secondary recipients transplanted with cells from treated mice compared with cells from untreated mice, with a reduction of BM blasts, Lin-/Sca-1+/c-Kit+, and progenitor populations by increased apoptosis of infiltrating blasts of diseased mice assessed in vivo by technicium-labeled annexin V single photon emission computed tomography and ex vivo by annexin V/7-amino actinomycin D flow cytometry, terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling, caspase 3 cleavage, and re-localization of the NRAS:BCL-2 complex from mitochondria to plasma membrane. Phosphoprotein analysis showed restoration of wild-type (WT) AKT or protein kinase B, extracellular signal-regulated kinase 1/2 and mitogen-activated protein kinase patterns in spleen cells after treatment, which showed reduced mitochondrial membrane potential. Exon specific gene expression profiling corroborates the reduction of leukemic cells, with an increase in expression of genes coding for stem cell development and maintenance, myeloid differentiation, and apoptosis. Myelodysplastic features persist underscoring targeting of BCL-2-mediated effects on MDS–AML transformation and survival of leukemic cells. PMID:23943652

  19. MicroRNAs expression in ox-LDL treated HUVECs: MiR-365 modulates apoptosis and Bcl-2 expression

    SciTech Connect

    Qin, Bing; Xiao, Bo; Liang, Desheng; Xia, Jian; Li, Ye; Yang, Huan

    2011-06-24

    Highlights: {yields} We evaluated the role of miRNAs in ox-LDL induced apoptosis in ECs. {yields} We found 4 up-regulated and 11 down-regulated miRNAs in apoptotic ECs. {yields} Target genes of the dysregulated miRNAs regulate ECs apoptosis and atherosclerosis. {yields} MiR-365 promotes ECs apoptosis via suppressing Bcl-2 expression. {yields} MiR-365 inhibitor alleviates ECs apoptosis induced by ox-LDL. -- Abstract: Endothelial cells (ECs) apoptosis induced by oxidized low-density lipoprotein (ox-LDL) is thought to play a critical role in atherosclerosis. MicroRNAs (miRNAs) are a class of noncoding RNAs that posttranscriptionally regulate the expression of genes involved in diverse cell functions, including differentiation, growth, proliferation, and apoptosis. However, whether miRNAs are associated with ox-LDL induced apoptosis and their effect on ECs is still unknown. Therefore, this study evaluated potential miRNAs and their involvement in ECs apoptosis in response to ox-LDL stimulation. Microarray and qRT-PCR analysis performed on human umbilical vein endothelial cells (HUVECs) exposed to ox-LDL identified 15 differentially expressed (4 up- and 11 down-regulated) miRNAs. Web-based query tools were utilized to predict the target genes of the differentially expressed miRNAs, and the potential target genes were classified into different function categories with the gene ontology (GO) term and KEGG pathway annotation. In particular, bioinformatics analysis suggested that anti-apoptotic protein B-cell CLL/lymphoma 2 (Bcl-2) is a target gene of miR-365, an apoptomir up-regulated by ox-LDL stimulation in HUVECs. We further showed that transfection of miR-365 inhibitor partly restored Bcl-2 expression at both mRNA and protein levels, leading to a reduction of ox-LDL-mediated apoptosis in HUVECs. Taken together, our findings indicate that miRNAs participate in ox-LDL-mediated apoptosis in HUVECs. MiR-365 potentiates ox-LDL-induced ECs apoptosis by regulating the

  20. The Human Bcl-2 Family Member Bcl-rambo Localizes to Mitochondria and Induces Apoptosis and Morphological Aberrations in Drosophila

    PubMed Central

    Matsushita, Yuka; Watanabe, Megumi; Vo, Nicole; Yoshida, Hideki; Yamaguchi, Masamitsu; Kataoka, Takao

    2016-01-01

    Bcl-2 family proteins play a central role in regulating apoptosis. We previously reported that human Bcl-rambo, also termed BCL2L13, localized to mitochondria and induced apoptosis when overexpressed in human embryonic kidney 293T cells. However, the physiological function of Bcl-rambo currently remains unclear. In the present study, human Bcl-rambo was ectopically expressed in Drosophila melanogaster. Bcl-rambo mainly localized to the mitochondria of Drosophila Schneider 2 (S2) cells. The overexpression of Bcl-rambo, but not Bcl-rambo lacking a C-terminal transmembrane domain, induced apoptosis in S2 cells. Moreover, the ectopic expression of Bcl-rambo by a GAL4-UAS system induced aberrant morphological changes characterized by atrophied wing, split thorax, and rough eye phenotypes. Bcl-rambo induced the activation of effector caspases in eye imaginal discs. The rough eye phenotype induced by Bcl-rambo was partly rescued by the co-expression of p35, Diap1, and Diap2. By using this Drosophila model, we showed that human Bcl-rambo interacted genetically with Drosophila homologues of adenine nucleotide translocators and the autophagy-related 8 protein. The results of the present study demonstrated that human Bcl-rambo localized to mitochondria and at least regulated an apoptosis signaling pathway in Drosophila. PMID:27348811

  1. BIM mediates synergistic killing of B-cell acute lymphoblastic leukemia cells by BCL-2 and MEK inhibitors.

    PubMed

    Korfi, K; Smith, M; Swan, J; Somervaille, T C P; Dhomen, N; Marais, R

    2016-04-07

    B-cell acute lymphoblastic leukemia (B-ALL) is an aggressive hematological disease that kills ~50% of adult patients. With the exception of some BCR-ABL1(+) patients who benefit from tyrosine kinase inhibitors, there are no effective targeted therapies for adult B-ALL patients and chemotherapy remains first-line therapy despite adverse side effects and poor efficacy. We show that, although the MEK/ERK pathway is activated in B-ALL cells driven by different oncogenes, MEK inhibition does not suppress B-ALL cell growth. However, MEK inhibition synergized with BCL-2/BCL-XL family inhibitors to suppress proliferation and induce apoptosis in B-ALL cells. We show that this synergism is mediated by the pro-apoptotic factor BIM, which is dephosphorylated as a result of MEK inhibition, allowing it to bind to and neutralize MCL-1, thereby enhancing BCL-2/BCL-XL inhibitor-induced cell death. This cooperative effect is observed in B-ALL cells driven by a range of genetic abnormalities and therefore has significant therapeutic potential.

  2. Skin-Derived Precursors against UVB-Induced Apoptosis via Bcl-2 and Nrf2 Upregulation

    PubMed Central

    Zhong, Jianqiao

    2016-01-01

    Bcl-2 and Nrf2 are critical factors in protecting cells against UVB-induced apoptosis. Hair-follicle-bulge stem cells could resist ionization through Bcl-2 upregulation. Skin-derived precursors (SKPs) dwelling on the bulge may be against UVB irradiation. Initially, SKPs were isolated and identified. Then, SKPs were exposed to UVB and grew in medium for 24 hours. CCK-8 assay, TUNEL, and Ki67 staining evaluated cells apoptosis/proliferation, while SA-βgal staining evaluated cells senescence and pH2AX immunostaining evaluated DNA damage. Meanwhile, Bcl-2, Nrf2, HO-1, Bax, and Bak expressions were assessed by qRT-PCR and western blot. Two weeks later, floating spheres appeared and were identified as SKPs. After UVB radiation, SKPs maintained spherical colonies and outnumbered unirradiated ones, showing high Ki67 expression and low TUNEL, SA-βgal, and pH2AX expression. Fibroblasts (FBs), however, displayed deformation, senescence, and reduction, with increased TUNEL, SA-βgal, and pH2AX expression. Moreover, Bcl-2 and Nrf2 mRNA expression were significantly higher than Bak and Bax in irradiated SKPs. Conversely, Bcl-2 and Nrf2 mRNA levels greatly decreased compared with Bax and Bak in irradiated FBs. Interestingly, SKPs showed higher protein levels of Bcl-2, Nrf2, and HO-1 than FBs. SKPs exert a beneficial effect on resisting UVB-induced apoptosis, which may be associated with Bcl-2 and Nrf2 upregulation. PMID:27635399

  3. Apoptosis in differentiating C2C12 muscle cells selectively targets Bcl-2-deficient myotubes.

    PubMed

    Schöneich, Christian; Dremina, Elena; Galeva, Nadezhda; Sharov, Victor

    2014-01-01

    Muscle cell apoptosis accompanies normal muscle development and regeneration, as well as degenerative diseases and aging. C2C12 murine myoblast cells represent a common model to study muscle differentiation. Though it was already shown that myogenic differentiation of C2C12 cells is accompanied by enhanced apoptosis in a fraction of cells, either the cell population sensitive to apoptosis or regulatory mechanisms for the apoptotic response are unclear so far. In the current study we characterize apoptotic phenotypes of different types of C2C12 cells at all stages of differentiation, and report here that myotubes of differentiated C2C12 cells with low levels of anti-apoptotic Bcl-2 expression are particularly vulnerable to apoptosis even though they are displaying low levels of pro-apoptotic proteins Bax, Bak and Bad. In contrast, reserve cells exhibit higher levels of Bcl-2 and high resistance to apoptosis. The transfection of proliferating myoblasts with Bcl-2 prior to differentiation did not protect against spontaneous apoptosis accompanying differentiation of C2C12 cells but led to Bcl-2 overexpression in myotubes and to significant protection from apoptotic cell loss caused by exposure to hydrogen peroxide. Overall, our data advocate for a Bcl-2-dependent mechanism of apoptosis in differentiated muscle cells. However, downstream processes for spontaneous and hydrogen peroxide induced apoptosis are not completely similar. Apoptosis in differentiating myoblasts and myotubes is regulated not through interaction of Bcl-2 with pro-apoptotic Bcl-2 family proteins such as Bax, Bak, and Bad.

  4. AP-2α-dependent regulation of Bcl-2/Bax expression affects apoptosis in the trophoblast.

    PubMed

    Zhang, Ling; Jia, Liting; Cui, Shihong; Shi, Ying; Chang, Aimin; Wang, Peng; Zhang, Zhan

    2012-12-01

    Enhanced apoptosis of the cytotrophoblast in early pregnancy is associated with a high risk of preeclampsia. We and others have previously reported that the transcriptional factor, activator protein AP-2α, suppressed trophoblast migration and invasion. However, it is not clear whether AP-2α affects apoptosis in trophoblast cells and whether it regulates expression of apoptosis-related factors Bcl-2 and Bax. We analyzed the expression of AP-2α, Bcl-2 and Bax in placental tissues in severe preeclamptic pregnancies and normotensive pregnancies using immunohistochemistry and real time-PCR. Further, apoptosis was assessed by flow cytometric analysis in the human trophoblastic cell line, BeWo cells, in which AP-2α expression was transiently overexpressed or down-regulated by siRNA. There was significantly higher expression of AP-2α and Bax, but lower expression of Bcl-2 in severe preeclampsia placentas as compared to the control placentas. Overexpression of AP-2α in BeWo cells led to an increased rate of apoptosis, whereas apoptosis was decreased when AP-2α expression was reduced. Furthermore, overexpression of AP-2α increased Bax expression and decreased Bcl-2 expression, whereas down-regulation of AP-2α expression resulted in a decrease in Bax expression and an increase in Bcl-2 expression. AP-2α regulates expression of Bcl-2 and Bax and apoptosis in BeWo cells. These results suggest that AP-2α-mediated regulation of Bcl-2 and Bax regulation influences apoptosis which in turn leads to the pathogenesis of preeclampsia.

  5. The novel antisense Bcl-2 inhibitor SPC2996 causes rapid leukemic cell clearance and immune activation in chronic lymphocytic leukemia.

    PubMed

    Dürig, J; Dührsen, U; Klein-Hitpass, L; Worm, J; Hansen, J B Rode; Ørum, H; Wissenbach, M

    2011-04-01

    SPC2996 is a novel locked nucleic acid phosphorothioate antisense molecule targeting the mRNA of the Bcl-2 oncoprotein. We investigated the mechanism of action of SPC2996 and the basis for its clinically observed immunostimulatory effects in chronic lymphocytic leukemia (CLL). Patients with relapsed CLL were treated with a maximum of six doses of SPC2996 (0.2-6 mg/kg) in a multicenter phase I trial. Microarray-based transcriptional profiling of circulating CLL cells was carried out before and after the first infusion of SPC2996 in 18 patients. Statistically significant transcriptomic changes were observed at doses 4 mg/kg and occurred as early as 24 h after the first infusion of the oligonucleotide. SPC2996 induced the upregulation of 466 genes including a large number of immune response and apoptotic regulator molecules, which were enriched for Toll-like receptor response genes. Serum measurements confirmed the release of pro-inflammatory cytokines including chemokine (C-C motif) ligand 3 (macrophage inflammatory protein 1α) and tumor necrosis factor-α, thereby validating the in vivo transcriptomic data at the protein level. SPC2996 caused a 50% reduction of circulating lymphocytes in five of 18 (28%) patients, which was found to be independent of its immunostimulatory and anti-Bcl-2 effects.

  6. A synthetic peptide targeting the BH4 domain of Bcl-2 induces apoptosis in multiple myeloma and follicular lymphoma cells alone or in combination with agents targeting the BH3-binding pocket of Bcl-2.

    PubMed

    Lavik, Andrew R; Zhong, Fei; Chang, Ming-Jin; Greenberg, Edward; Choudhary, Yuvraj; Smith, Mitchell R; McColl, Karen S; Pink, John; Reu, Frederic J; Matsuyama, Shigemi; Distelhorst, Clark W

    2015-09-29

    Bcl-2 inhibits apoptosis by two distinct mechanisms but only one is targeted to treat Bcl-2-positive malignancies. In this mechanism, the BH1-3 domains of Bcl-2 form a hydrophobic pocket, binding and inhibiting pro-apoptotic proteins, including Bim. In the other mechanism, the BH4 domain mediates interaction of Bcl-2 with inositol 1,4, 5-trisphosphate receptors (IP3Rs), inhibiting pro-apoptotic Ca2+ signals. The current anti-Bcl-2 agents, ABT-263 (Navitoclax) and ABT-199 (Venetoclax), induce apoptosis by displacing pro-apoptotic proteins from the hydrophobic pocket, but do not inhibit Bcl-2-IP3R interaction. Therefore, to target this interaction we developed BIRD-2 (Bcl-2 IP3 Receptor Disruptor-2), a decoy peptide that binds to the BH4 domain, blocking Bcl-2-IP3R interaction and thus inducing Ca2+-mediated apoptosis in chronic lymphocytic leukemia, multiple myeloma, and follicular lymphoma cells, including cells resistant to ABT-263, ABT-199, or the Bruton's tyrosine kinase inhibitor Ibrutinib. Moreover, combining BIRD-2 with ABT-263 or ABT-199 enhances apoptosis induction compared to single agent treatment. Overall, these findings provide strong rationale for developing novel therapeutic agents that mimic the action of BIRD-2 in targeting the BH4 domain of Bcl-2 and disrupting Bcl-2-IP3R interaction.

  7. bcl-2 transgene expression can protect neurons against developmental and induced cell death.

    PubMed Central

    Farlie, P G; Dringen, R; Rees, S M; Kannourakis, G; Bernard, O

    1995-01-01

    The bcl-2 protooncogene, which protects various cell types from apoptotic cell death, is expressed in the developing and adult nervous system. To explore its role in regulation of neuronal cell death, we generated transgenic mice expressing Bcl-2 under the control of the neuron-specific enolase promoter, which forced expression uniquely in neurons. Sensory neurons isolated from dorsal root ganglia of newborn mice normally require nerve growth factor for their survival in culture, but those from the bcl-2 transgenic mice showed enhanced survival in its absence. Furthermore, apoptotic death of motor neurons after axotomy of the sciatic nerve was inhibited in these mice. The number of neurons in two neuronal populations from the central and peripheral nervous system was increased by 30%, indicating that Bcl-2 expression can protect neurons from cell death during development. The generation of these transgenic mice suggests that Bcl-2 may play an important role in survival of neurons both during development and throughout adult life. Images Fig. 1 Fig. 2 Fig. 4 PMID:7753817

  8. Bicalutamide-induced hypoxia potentiates RUNX2-mediated Bcl-2 expression resulting in apoptosis resistance

    PubMed Central

    Browne, G; Nesbitt, H; Ming, L; Stein, G S; Lian, J B; McKeown, S R; Worthington, J

    2012-01-01

    Background: We have previously shown that hypoxia selects for more invasive, apoptosis-resistant LNCaP prostate cancer cells, with upregulation of the osteogenic transcription factor RUNX2 and the anti-apoptotic factor Bcl-2 detected in the hypoxia-selected cells. Following this observation, we questioned through what biological mechanism this occurs. Methods: We examined the effect of hypoxia on RUNX2 expression and the role of RUNX2 in the regulation of Bcl-2 and apoptosis resistance in prostate cancer. Results: Hypoxia increased RUNX2 expression in vitro, and bicalutamide-treated LNCaP tumours in mice (previously shown to have increased tumour hypoxia) exhibited increased RUNX2 expression. In addition, RUNX2-overexpressing LNCaP cells showed increased cell viability, following bicalutamide and docetaxel treatment, which was inhibited by RUNX2 siRNA; a range of assays demonstrated that this was due to resistance to apoptosis. RUNX2 expression was associated with increased Bcl-2 levels, and regulation of Bcl-2 by RUNX2 was confirmed through chromatin immunoprecipitation (ChIP) binding and reporter assays. Moreover, a Q-PCR array identified other apoptosis-associated genes upregulated in the RUNX2-overexpressing LNCaP cells. Conclusion: This study establishes a contributing mechanism for progression of prostate cancer cells to a more apoptosis-resistant and thus malignant phenotype, whereby increased expression of RUNX2 modulates the expression of apoptosis-associated factors, specifically Bcl-2. PMID:23073173

  9. HOX gene expression predicts response to BCL-2 inhibition in acute myeloid leukemia.

    PubMed

    Kontro, M; Kumar, A; Majumder, M M; Eldfors, S; Parsons, A; Pemovska, T; Saarela, J; Yadav, B; Malani, D; Fløisand, Y; Höglund, M; Remes, K; Gjertsen, B T; Kallioniemi, O; Wennerberg, K; Heckman, C A; Porkka, K

    2017-02-01

    Inhibitors of B-cell lymphoma-2 (BCL-2) such as venetoclax (ABT-199) and navitoclax (ABT-263) are clinically explored in several cancer types, including acute myeloid leukemia (AML), to selectively induce apoptosis in cancer cells. To identify robust biomarkers for BCL-2 inhibitor sensitivity, we evaluated the ex vivo sensitivity of fresh leukemic cells from 73 diagnosed and relapsed/refractory AML patients, and then comprehensively assessed whether the responses correlated to specific mutations or gene expression signatures. Compared with samples from healthy donor controls (nonsensitive) and chronic lymphocytic leukemia (CLL) patients (highly sensitive), AML samples exhibited variable responses to BCL-2 inhibition. Strongest CLL-like responses were observed in 15% of the AML patient samples, whereas 32% were resistant, and the remaining exhibited intermediate responses to venetoclax. BCL-2 inhibitor sensitivity was associated with genetic aberrations in chromatin modifiers, WT1 and IDH1/IDH2. A striking selective overexpression of specific HOXA and HOXB gene transcripts were detected in highly BCL-2 inhibitor sensitive samples. Ex vivo responses to venetoclax showed significant inverse correlation to β2-microglobulin expression and to a lesser degree to BCL-XL and BAX expression. As new therapy options for AML are urgently needed, the specific HOX gene expression pattern can potentially be used as a biomarker to identify venetoclax-sensitive AML patients for clinical trials.

  10. Removal of the BH4 Domain from Bcl-2 Protein Triggers an Autophagic Process that Impairs Tumor Growth12

    PubMed Central

    Trisciuoglio, Daniela; De Luca, Teresa; Desideri, Marianna; Passeri, Daniela; Gabellini, Chiara; Scarpino, Stefania; Liang, Chengyu; Orlandi, Augusto; Del Bufalo, Donatella

    2013-01-01

    Here, we show that forced expression of a B-cell lymphoma 2 (bcl-2) protein lacking residues 1 to 36 at the N-terminal, including the entire Bcl-2 homology 4 (BH4) domain, determines reduction of in vitro and in vivo human melanoma growth. Noteworthy, melanoma cells in vivo exhibit markedly increased autophagy, as response to expression of bcl-2 protein deleted of its BH4 domain. This observation led to the identification of a novel gain of function for bcl-2 protein lacking the BH4 domain. In particular, upon different autophagic stimuli in vitro, overexpression of bcl-2 protein deleted of BH4 domain induces autophagosome accumulation, conversion of microtubule-associated protein 1 light chain 3B-II, reduced expression of p62/SQSTM1 protein, and thereby enhanced autophagic flux. The relevance of Beclin-1 is evidenced by the fact that 1) the autophagy-promoting and growth-inhibiting properties are partially rescued by Beclin-1 knockdown in cells expressing bcl-2 protein lacking the BH4 domain, 2) Beclin-1 only interacts with wild-type but not with deleted bcl-2, and 3) BH4 domain removal from bcl-2 protein does not influence in vitro and in vivo growth of tumor cells expressing low levels of endogenous Beclin-1. These results provide new insight into molecular mechanism of bcl-2 functions and represent a rationale for the development of agents interfering with the BH4 domain of bcl-2 protein. PMID:23479509

  11. Diffuse large B-cell lymphoma with concurrent high MYC and BCL2 expression shows evidence of active B-cell receptor signaling by quantitative immunofluorescence

    PubMed Central

    Kovach, Alexandra E.; Le, Long P.; Feng, Derek; Baxter, Richard H. G.; Sohani, Aliyah R.

    2017-01-01

    B-cell receptor (BCR)-mediated signaling plays an important role in the pathogenesis of a subset of diffuse large B-cell lymphoma (DLBCL), and novel agents targeting this pathway are now in clinical use. We have previously identified a signature of active BCR signaling on formalin-fixed paraffin-embedded specimens using quantitative immunofluorescence, allowing for identification of patients who might benefit from anti-BCR therapies. We sought to characterize the clinicopathologic significance of active BCR signaling in DLBCL by correlating measures of signaling intensity with clinical features and various tumor cell characteristics. High MYC and concurrent high MYC and BCL2 double-expression was positively correlated with individual markers of active BCR signaling and cases with MYC/BCL2 double-expression showed overall greater BCR activation compared to cases lacking double-expression. Our findings suggest that the BCR signaling pathway may be more active in MYC/BCL2 double-expressor DLBCL and may represent a rational therapeutic target in this aggressive DLBCL subgroup. PMID:28212447

  12. Polydatin promotes apoptosis through upregulation the ratio of Bax/Bcl-2 and inhibits proliferation by attenuating the β-catenin signaling in human osteosarcoma cells

    PubMed Central

    Xu, Ge; Kuang, Ge; Jiang, Wengao; Jiang, Rong; Jiang, Dianming

    2016-01-01

    Osteosarcoma is the most prevalent primary malignant bone tumor mainly endangering young adults. In this study, we explore whether polydatin (PD), a glycoside form of resveratrol, is effective for osteosarcoma. Our results showed that PD dose-dependently inhibited proliferation and promoted apoptosis in 143B and MG63 osteosarcoma cells, examined by MTT assay and Annexin V-FITC apoptosis detection. Further, we found PD increased expression of Bax and attenuated expression of Bcl-2, and consequently augmented caspase-3 activity. Moreover, PD also dose-dependently inhibited β-catenin signaling pathway as indicated by decreased β-catenin expression and activity, while overexpression of β-catenin by adenoviruses system could abrogate the anti-tumor effect of PD. Our finding indicated that PD could inhibit the proliferation by inhibiting the β-catenin signaling and induce apoptosis via upregulation the ratio of Bax/Bcl-2 in human osteosarcoma cells. PMID:27158379

  13. Cisplatin-induced apoptosis in non-small-cell lung cancer cells is dependent on Bax- and Bak-induction pathway and synergistically activated by BH3-mimetic ABT-263 in p53 wild-type and mutant cells.

    PubMed

    Matsumoto, Masaru; Nakajima, Wataru; Seike, Masahiro; Gemma, Akihiko; Tanaka, Nobuyuki

    2016-04-29

    Cisplatin is a highly effective anticancer drug for treatment of various tumors including non-small-cell lung cancer (NSCLC), and is especially useful in cases nonresponsive to molecular-targeted drugs. Accumulating evidence has shown that cisplatin activates the p53-dependent apoptotic pathway, but it also induces apoptosis in p53-mutated cancer cells. Here we demonstrated that DNA-damage inducible proapoptotic BH3 (Bcl-2 homology region 3)-only Bcl-2 family members, Noxa, Puma, Bim and Bid, are not involved in cisplatin-induced apoptosis in human NSCLC cell lines. In contrast, the expression of proapoptotic multidomain Bcl-2-family members, Bak and Bax, was induced by cisplatin in p53-dependent and -independent manners, respectively. Moreover, in wild-type p53-expressing cells, cisplatin mainly used the Bak-dependent apoptotic pathway, but this apoptotic pathway shifted to the Bax-dependent pathway by loss-of-function of p53. Furthermore, both Bak- and Bax-induced apoptosis was enhanced by the antiapoptotic Bcl-2 family member, Bcl-XL knockdown, but not by Mcl-1 knockdown. From this result, we tested the effect of ABT-263 (Navitoclax), the specific inhibitor of Bcl-2 and Bcl-XL, but not Mcl-1, and found that ABT-263 synergistically enhanced cisplatin-induced apoptosis in NSCLC cells in the presence or absence of p53. These results indicate a novel regulatory system in cisplatin-induced NSCLC cell apoptosis, and a candidate efficient combination chemotherapy method against lung cancers.

  14. A comparison of pathway-independent and pathway-dependent methods in the calculation of conformational free enthalpy differences.

    PubMed

    Lin, Zhixiong; van Gunsteren, Wilfred F

    2016-01-01

    The multistep umbrella sampling method, which belongs to pathway-dependent methods to calculate conformational free enthalpy differences, is used to calculate the free enthalpy difference between a right-handed 2.710/12 -helix and a left-handed 314 -helix of a hexa-β-peptide in methanol solution. The same conformational free enthalpy difference was previously investigated using pathway-independent methods such as direct counting and enveloping distribution sampling. Our results show that the pathway-dependent simulations are sensitive to the choice of the pathway and its parameter values. A pathway based on restraining distances of hydrogen-bonding atom pairs shows poor sampling for two different values of the restraining force constant. Another pathway based on restraining backbone dihedral angles did smoothly sample the transition between the two helical conformations, but only with a proper choice of the restraining force constant. The results illustrate that if, and only if, a proper pathway and proper parameters are chosen, the multistep umbrella sampling can be almost 50 times more efficient than the pathway-independent methods in this case. The analysis illustrates the advantages and pitfalls of the much used multistep umbrella sampling methodology.

  15. RML prions act through Mahogunin and Attractin-independent pathways.

    PubMed

    Gunn, Teresa M; Carlson, George A

    2013-01-01

    While the conversion of the normal form of prion protein to a conformationally distinct pathogenic form is recognized to be the primary cause of prion disease, it is not clear how this leads to spongiform change, neuronal dysfunction and death. Mahogunin ring finger-1 (Mgrn1) and Attractin (Atrn) null mutant mice accumulate vacuoles throughout the brain that appear very similar to those associated with prion disease, but they do not accumulate the protease-resistant scrapie form of the prion protein or become sick. A study demonstrating an interaction between cytosolically-exposed prion protein and MGRN1 suggested that disruption of MGRN1 function may contribute to prion disease pathogenesis, but we recently showed that neither loss of MGRN1 nor MGRN1 overexpression influences the onset or progression of prion disease following intracerebral inoculation with Rocky Mountain Laboratory prions. Here, we show that loss of ATRN also has no effect on prion disease onset or progression and discuss possible mechanisms that could cause vacuolation of the central nervous system in Mgrn1 and Atrn null mutant mice and whether the same pathways might contribute to this intriguing phenotype in prion disease.

  16. UV induces VEGF through a TNF-alpha independent pathway.

    PubMed

    Kosmadaki, Maria G; Yaar, Mina; Arble, Bennett L; Gilchrest, Barbara A

    2003-03-01

    Vascular endothelial growth factor (VEGF) is a potent keratinocyte-derived angiogenic factor. Prior reports suggest that following UV irradiation VEGF in keratinocytes is induced primarily by tumor necrosis factor (TNF)- alpha, a cytokine synthesized and secreted by keratinocytes after UV irradiation. We investigated whether blocking TNF-alpha binding to its receptors would inhibit UV-induced VEGF expression and secretion in the keratinocyte-derived line SCC-12F. Irradiation with physiologic UV doses (30 mJ/cm2) substantially induced VEGF mRNA in this cell line, as expected, and mRNA induction was followed by increased VEGF in medium conditioned by UV-irradiated cells. Also as expected, TNF-alpha induced VEGF expression and secretion in a dose-dependent manner. Addition of a hexapeptide (Ac-KWIIVW-NH2), known to block TNF-alpha binding to its receptors, abrogated this TNF-alpha effect on VEGF mRNA induction. However, addition of the peptide to cells immediately after UV irradiation did not substantially affect VEGF mRNA induction or secretion into the medium. Our results suggest that VEGF induction after UV irradiation is mediated by multiple mechanisms and that blocking a single pathway does not affect the response.

  17. MiR-34a-3p alters proliferation and apoptosis of meningioma cells in vitro and is directly targeting SMAD4, FRAT1 and BCL2.

    PubMed

    Werner, Tamara V; Hart, Martin; Nickels, Ruth; Kim, Yoo-Jin; Menger, Michael D; Bohle, Rainer M; Keller, Andreas; Ludwig, Nicole; Meese, Eckart

    2017-03-23

    Micro (mi)RNAs are short, noncoding RNAs and deregulation of miRNAs and their targets are implicated in tumor generation and progression in many cancers. Meningiomas are mostly benign, slow growing tumors of the central nervous system with a small percentage showing a malignant phenotype.Following in silico prediction of potential targets of miR-34a-3p, SMAD4, FRAT1, and BCL2 have been confirmed as targets by dual luciferase assays with co-expression of miR-34a-3p and reporter gene constructs containing the respective 3'UTRs. Disruption of the miR-34a-3p binding sites in the 3'UTRs resulted in loss of responsiveness to miR-34a-3p overexpression. In meningioma cells, overexpression of miR-34a-3p resulted in decreased protein levels of SMAD4, FRAT1 and BCL2, while inhibition of miR-34a-3p led to increased levels of these proteins as confirmed by Western blotting. Furthermore, deregulation of miR-34a-3p altered cell proliferation and apoptosis of meningioma cells in vitro.We show that SMAD4, FRAT1 and BCL2 are direct targets of miR-34a-3p and that deregulation of miR-34a-3p alters proliferation and apoptosis of meningioma cells in vitro. As part of their respective signaling pathways, which are known to play a role in meningioma genesis and progression, deregulation of SMAD4, FRAT1 and BCL2 might contribute to the aberrant activation of these signaling pathways leading to increased proliferation and inhibition of apoptosis in meningiomas.

  18. Embedded Together: The Life and Death Consequences of Interaction of the Bcl-2 Family with Membranes

    PubMed Central

    Leber, Brian; Lin, Jialing; Andrews, David W.

    2010-01-01

    Permeabilization of the outer mitochondrial membrane is the point of no return in most programmed cell deaths. This critical step is mainly regulated by the various protein-protein and protein-membrane interactions of the Bcl-2 family proteins. The two main models for regulation of mitochondrial outer membrane permeabilization, direct activation and displacement do not account for all of the experimental data and both largely neglect the importance of the membrane. We propose the embedding together model to emphasize the critical importance of Bcl-2 family protein interactions with and within membranes. The embedding together model proposes that both pro- and anti-apoptotic Bcl-2 family proteins engage in similar dynamic interactions that are governed by membrane dependent conformational changes and culminate in either aborted or productive membrane permeabilization depending on the final oligomeric state of pro-apoptotic Bax and/or Bak. PMID:17453159

  19. [Study on histology and the expression of Bax and Bcl-2 after cerebral contusion in rats].

    PubMed

    Chen, L

    2000-11-01

    To set up the experimental model of focal cerebral contusions in rats, and to study the histology and the expression of Bax and Bcl-2 after cerebral catusions. It was found that neurons and astrocytes around the wound area were changed morphologically and that polymorphonuclear leucocytes were present at 12-24 h after injury. A lot of foamy cells and astrocytes having a big dark nucleus appeared around the wound area on the 4th day after injury. On the 8-10th day, liquefaction necrosis was seen in areas of contusions. On the 12-14th day, the contusion focus healed up and became cystiform or glial node. Meantime, lots of astrocytes, capillary vessel and hemosiderin were observed. The expression of Bax and Bcl-2 increased after injury. There existed a relationship between increased Bax/Bcl-2 and different intervals after brain injury.

  20. Autonomous proliferation and bcl-2 expression involving haematopoietic cells in patients with myelodysplastic syndrome.

    PubMed Central

    Bincoletto, C.; Saad, S. T.; Soares da Silva, E.; Queiroz, M. L.

    1998-01-01

    In this work, we investigated the autonomous proliferation, bcl-2 expression and number of apoptotic cells in the bone marrow of patients with confirmed diagnosis of myelodysplastic syndromes (MDS). Normal bone marrow cells obtained from donors of the Clinical Hospital of this university were used as a control. The autonomous proliferation, evaluated by clonal culture without exogenous growth factor, and the number of apoptotic cells in bone marrow kept for 10 days in liquid cultures at 37 degrees C and 5% carbon dioxide, were significantly greater in MDS patients than in control subjects (P = 0.001, Wilcoxon). However, bcl-2 expression, measured by immunocytochemistry, was significantly lower in MDS patients than in normal individuals (P = 0.002, Wilcoxon). These results suggest that the high proliferation activity in MDS patients may be counteracted by the high level of medullar cell death, which might be related to the lower bcl-2 expression. PMID:9744502

  1. Blastic Plasmacytoid Dendritic Cell Neoplasm Is Dependent on BCL2 and Sensitive to Venetoclax.

    PubMed

    Montero, Joan; Stephansky, Jason; Cai, Tianyu; Griffin, Gabriel K; Cabal-Hierro, Lucia; Togami, Katsuhiro; Hogdal, Leah J; Galinsky, Ilene; Morgan, Elizabeth A; Aster, Jon C; Davids, Matthew S; LeBoeuf, Nicole R; Stone, Richard M; Konopleva, Marina; Pemmaraju, Naveen; Letai, Anthony; Lane, Andrew A

    2017-02-01

    Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is an aggressive hematologic malignancy with dismal outcomes for which no standard therapy exists. We found that primary BPDCN cells were dependent on the antiapoptotic protein BCL2 and were uniformly sensitive to the BCL2 inhibitor venetoclax, as measured by direct cytotoxicity, apoptosis assays, and dynamic BH3 profiling. Animals bearing BPDCN patient-derived xenografts had disease responses and improved survival after venetoclax treatment in vivo Finally, we report on 2 patients with relapsed/refractory BPDCN who received venetoclax off-label and experienced significant disease responses. We propose that venetoclax or other BCL2 inhibitors undergo expedited clinical evaluation in BPDCN, alone or in combination with other therapies. In addition, these data illustrate an example of precision medicine to predict treatment response using ex vivo functional assessment of primary tumor tissue, without requiring a genetic biomarker.

  2. The Development and Current Use of BCL-2 Inhibitors for the Treatment of Chronic Lymphocytic Leukemia.

    PubMed

    Lampson, Benjamin L; Davids, Matthew S

    2017-01-23

    The BCL-2 family of proteins integrates pro- and anti-apoptotic signals within the cell and is responsible for initiation of caspase-dependent apoptosis. Chronic lymphocytic leukemia (CLL) cells are particularly dependent on the anti-apoptotic protein BCL-2 for their survival, making this an attractive therapeutic target in CLL. Several early efforts to create inhibitors of the anti-apoptotic family members faced significant challenges, but eventually, the BCL-2 specific inhibitor venetoclax moved forward in CLL. Overall and complete response rates to venetoclax monotherapy in relapsed, refractory CLL are approximately 80 and 20%, respectively, even in patients with high-risk 17p deletion. Toxicities have been manageable and include neutropenia, diarrhea, and nausea. The risk of tumor lysis syndrome (TLS), seen in early experience with the drug, has been mitigated by the use of appropriate TLS risk assessment, prophylaxis, and management. Future studies of venetoclax will focus on combination approaches, predictive biomarker discovery, and mechanisms of resistance.

  3. [Effect of clofarabine on proliferation and Bcl-2 expression of NB4 cells].

    PubMed

    Liu, Hai-Bo; Zhang, Mei; Li, Cheng-Liang; He, Peng-Cheng

    2012-06-01

    The aim of this study was to observe the effect of clofarabine on proliferation of NB4 cells and its possible mechanism. MTT method was used to detect proliferation of NB4 cells treated with clofarabine 0.01 - 0.1 µmol/L for 48 h. The treated with clofarabine 0.01 - 0.1 µmol/L for 24 h, apoptosis rate and Bcl-2 expression of NB4 cells were measured by flow cytometry and Western blot respectively. The results showed that clofarabine inhibited proliferation of NB4 cells in a concentration-depended manner (r = 0.78). After treated with clofarabine for 24 h, apoptosis rate of NB4 cells increased and Bcl-2 expression in NB4 cells decreased obviously (P < 0.05). It is concluded that clofarabine inhibits proliferation of NB4 cells, which may be related with the down-regulation of Bcl-2 and induction of apoptosis.

  4. Apoptotic machinery: the Bcl-2 family proteins in the role of inspectors and superintendents.

    PubMed

    Tichý, Ales

    2006-01-01

    Programmed cell death, apoptosis, plays an integral role in a variety of biological events, e.g. morphogenesis, removal of unwanted or harmful cells, tissue homeostasis etc. Members of the Bcl-2 family have been described as the key players in the regulation of the apoptotic process. This family consists of proteins that prevent apoptosis (Bcl-2-like) and two structurally distinct subgroups (Bax-like and BH3-only) that on the contrary promote cell death. Majority of their response is concentrated to the mitochondrial level. In this paper, besides reviewing some new information in this field we focused on how they interact among each other and on the way they sense and influence the death signals from the environment. Here, we compare Bcl-2 family to inspectors and superintendents since they supervise the manufacturing process of cell death and they determine whether the cell will die or it will resist and survive.

  5. Quinacrine induces apoptosis in human leukemia K562 cells via p38 MAPK-elicited BCL2 down-regulation and suppression of ERK/c-Jun-mediated BCL2L1 expression

    SciTech Connect

    Changchien, Jung-Jung; Chen, Ying-Jung; Huang, Chia-Hui; Cheng, Tian-Lu; Lin, Shinne-Ren; Chang, Long-Sen

    2015-04-01

    Although previous studies have revealed the anti-cancer activity of quinacrine, its effect on leukemia is not clearly resolved. We sought to explore the cytotoxic effect and mechanism of quinacrine action in human leukemia K562 cells. Quinacrine induced K562 cell apoptosis accompanied with ROS generation, mitochondrial depolarization, and down-regulation of BCL2L1 and BCL2. Upon exposure to quinacrine, ROS-mediated p38 MAPK activation and ERK inactivation were observed in K562 cells. Quinacrine-induced cell death and mitochondrial depolarization were suppressed by the p38MAPK inhibitor SB202190 and constitutively active MEK1 over-expression. Activation of p38 MAPK was shown to promote BCL2 degradation. Further, ERK inactivation suppressed c-Jun-mediated transcriptional expression of BCL2L1. Over-expression of BCL2L1 and BCL2 attenuated quinacrine-evoked mitochondrial depolarization and rescued the viability of quinacrine-treated cells. Taken together, our data indicate that quinacrine-induced K562 cell apoptosis is mediated through mitochondrial alterations triggered by p38 MAPK-mediated BCL2 down-regulation and suppression of ERK/c-Jun-mediated BCL2L1 expression. - Highlights: • Quinacrine induces K562 cell apoptosis via down-regulation of BCL2 and BCL2L1. • Quinacrine induces p38 MAPK activation and ERK inactivation in K562 cells. • Quinacrine elicits p38 MAPK-mediated BCL2 down-regulation. • Quinacrine suppresses ERK/c-Jun-mediated BCL2L1 expression.

  6. Integrated strategy reveals the protein interface between cancer targets Bcl-2 and NAF-1

    PubMed Central

    Tamir, Sagi; Rotem-Bamberger, Shahar; Katz, Chen; Morcos, Faruck; Hailey, Kendra L.; Zuris, John A.; Wang, Charles; Conlan, Andrea R.; Lipper, Colin H.; Paddock, Mark L.; Mittler, Ron; Onuchic, José N.; Jennings, Patricia A.; Friedler, Assaf; Nechushtai, Rachel

    2014-01-01

    Life requires orchestrated control of cell proliferation, cell maintenance, and cell death. Involved in these decisions are protein complexes that assimilate a variety of inputs that report on the status of the cell and lead to an output response. Among the proteins involved in this response are nutrient-deprivation autophagy factor-1 (NAF-1)- and Bcl-2. NAF-1 is a homodimeric member of the novel Fe-S protein NEET family, which binds two 2Fe-2S clusters. NAF-1 is an important partner for Bcl-2 at the endoplasmic reticulum to functionally antagonize Beclin 1-dependent autophagy [Chang NC, Nguyen M, Germain M, Shore GC (2010) EMBO J 29(3):606–618]. We used an integrated approach involving peptide array, deuterium exchange mass spectrometry (DXMS), and functional studies aided by the power of sufficient constraints from direct coupling analysis (DCA) to determine the dominant docked conformation of the NAF-1–Bcl-2 complex. NAF-1 binds to both the pro- and antiapoptotic regions (BH3 and BH4) of Bcl-2, as demonstrated by a nested protein fragment analysis in a peptide array and DXMS analysis. A combination of the solution studies together with a new application of DCA to the eukaryotic proteins NAF-1 and Bcl-2 provided sufficient constraints at amino acid resolution to predict the interaction surfaces and orientation of the protein–protein interactions involved in the docked structure. The specific integrated approach described in this paper provides the first structural information, to our knowledge, for future targeting of the NAF-1–Bcl-2 complex in the regulation of apoptosis/autophagy in cancer biology. PMID:24706857

  7. CD40 ligand, Bcl-2 and apoptosis in B-chronic lymphocytic leukemia.

    PubMed

    Hussein, Ola A; Omran, Alaa A; Elnaggar, Amina M; Fathy, Ayman

    2009-01-01

    Chronic lymphocytic leukemia (CLL) is a haematopoetic neoplasm caused primarily by defects in apoptosis mechanisms and complicated by progressive marrow failure, immunosupression and increased resistance to chemotherapy. The CD40-CD40 ligand (CD40L) interaction has been shown to significantly increase antigen presentation in normal and malignant B-cells and it is a powerful regulator of cell survival. Bcl-2 expression is common in CLL and is associated with decreased overall survival. Our objective was to asses CD40 ligand (CD154) and Bcl-2 expressions and their correlation with clinical and laboratory features in CLL patients. This study was conducted on 40 subjects, including 10 healthy volunteers as the control group and 30 patients presented with de novo chronic lymphocytic leukemia (CLL), all of them were subjected to thorough history taking, full clinical examinations, routine laboratory investigations and flowcytometric assessment of CD40L and Bcl-2 on lymphocytes. There was a highly significant increase in TLC, absolute lymphocytic count, serum LDH, B2-microglobulin and Bcl-2 expression (P<0.001); there was a significant increase in CD40L expression (P<0.05); whereas there was a highly significant decrease in hemoglobin concentration and platelets count between the study group (P<0.001). There was no significant difference as regard direct Coombs' test between both groups. There was no significant relation between CD154 expression and clinical findings, Rai staging system and other laboratory parameters. CD40L expression is increased with staging of Modified Rai staging system but not reaching the significant level. There was no significant correlation between CD154 expression and some of clinical and laboratory parameters, whereas there was only significantly negative correlation between Bcl-2 expression and both haemoglobin concentration and platelets count (P<0.001). Combination of Bcl-2 antisense oligonucleotide with conventional chemotherapeutic drugs

  8. Biophysical Basis of the Promiscuous Binding of Bcl2 Apoptotic Repressor to BH3 Ligands

    PubMed Central

    Bhat, Vikas; Olenick, Max B.; Schuchardt, Brett J.; Mikles, David C.; McDonald, Caleb B.; Farooq, Amjad

    2013-01-01

    Bcl2 apoptotic repressor carries out its function by virtue of its ability to bind to BH3 domains of various pro-apoptotic regulators in a highly promiscuous manner. Herein, we investigate the biophysical basis of such promiscuity of Bcl2 toward its cognate BH3 ligands. Our data show that while the BH3 ligands harboring the LXXXAD motif bind to Bcl2 with submicromolar affinity, those with the LXXX[G/S]D motif afford weak interactions. This implies that the replacement of alanine at the fourth position (A+4)—relative to the N-terminal leucine (L0) within the LXXXAD motif—to glycine/serine results in the loss of free energy of binding. Consistent with this notion, the A+4 residue within the BH3 ligands harboring the LXXXAD motif engages in key intermolecular van der Waals contacts with A149 lining the ligand binding groove within Bcl2, while A+4G/S substitution results in the disruption of such favorable binding interactions. Of particular interest is the observation that while increasing ionic strength has little or negligible effect on the binding of high-affinity BH3 ligands harboring the LXXXAD motif, the binding of those with the LXXX[G/S]D motif in general experiences a varying degree of enhancement. This salient observation is indicative of the fact that hydrophobic forces not only play a dominant but also a universal role in driving the Bcl2-BH3 interactions. Taken together, our study sheds light on the molecular basis of the factors governing the promiscuous binding of Bcl2 to pro-apoptotic regulators and thus bears important consequences on the development of rational therapeutic approaches. PMID:23996493

  9. Therapeutic potential of a peptide targeting BCL-2 cell guardians in cancer.

    PubMed

    Adams, Jerry M

    2012-06-01

    A promising approach to cancer therapy is to elicit apoptosis with "BH3 mimetic" drugs, which target proteins of the BCL-2 family. As of yet, however, such drugs can target only certain BCL-2 family proteins. Hence, in this issue of the JCI, LaBelle et al. assess instead the therapeutic potential of a "stapled" BH3 peptide from the BIM protein, which inactivates all its prosurvival relatives. The peptide killed cultured hematologic tumor cells and abated growth of a leukemia xenograft, without perturbing the hematopoietic compartment. Hence, such peptides might eventually provide a new way to treat refractory leukemias.

  10. BCL-2: Long and winding path from discovery to therapeutic target.

    PubMed

    Schenk, Robyn L; Strasser, Andreas; Dewson, Grant

    2017-01-15

    In 1988, the BCL-2 protein was found to promote cancer by limiting cell death rather than enhancing proliferation. This discovery set the wheels in motion for an almost 30 year journey involving many international research teams that has recently culminated in the approval for a drug, ABT-199/venetoclax/Venclexta that targets this protein in the treatment of cancer. This review will describe the long and winding path from the discovery of this protein and understanding the fundamental process of apoptosis that BCL-2 and its numerous homologues control, through to its exploitation as a drug target that is set to have significant benefit for cancer patients.

  11. Differential expression of Bcl-2 and Bax during gastric ischemia-reperfusion of rats

    PubMed Central

    Qiao, Wei-Li; Wang, Guang-Ming; Shi, Yue; Wu, Jin-Xia; Qi, You-Jian; Zhang, Jian-Fu; Sun, Hong; Yan, Chang-Dong

    2011-01-01

    AIM: To investigate expression of Bcl-2 and Bax in gastric ischemia-reperfusion (GI-R) and involvement of extracellular signal-regulated kinase (ERK) 1/2 activation. METHODS: The GI-R model was established by ligature of the celiac artery for 30 min and reperfusion in Sprague-Dawley rats. Rats were assigned to groups in accordance with their evaluation period: control, 0, 0.5, 1, 3, 6, 24, 48, and 72 h. Expression and distribution of Bcl-2 and Bax proteins were analyzed by immunohistochemistry and western blotting in gastric tissue samples after sacrifice. RESULTS: Compared with controls, the percentage of positive cells and protein levels of Bcl-2 decreased in the early phases of reperfusion, reached its minimum at 1 h (P < 0.05); it then increased, reaching its peak at 24 h of reperfusion (P < 0.05). The pattern of Bax expression was opposite to that of Bcl-2. Bax expression increased after reperfusion, with its peak at 1 h of reperfusion (P < 0.05), and then it decreased gradually to a minimum at 24 h after reperfusion (P < 0.05). On the other hand, inhibition of activation of ERK1/2 induced by PD98059, a specific upstream MEK inhibitor, had significant effects on Bcl-2 and Bax in GI-R. Compared with GI-R treatment only at 3 h of reperfusion, PD98059 reduced the number of Bcl-2 positive cells (0.58% of R3h group, P < 0.05) and Bcl-2 protein level (74% of R3h group, P < 0.05) but increased the number of Bax-positive cells (1.33-fold vs R3h group, P < 0.05) and Bax protein level (1.35-fold of R3h group, P < 0.05). CONCLUSION: These results indicated that the Bcl-2 and Bax played a pivotal role in the gastric mucosal I-R injury and repair by activation of ERK1/2. PMID:21483632

  12. Oocyte-secreted growth differentiation factor 9 inhibits BCL-2-interacting mediator of cell death-extra long expression in porcine cumulus cell.

    PubMed

    Wang, Xian-Long; Wang, Kun; Zhao, Shuan; Wu, Yi; Gao, Hui; Zeng, Shen-Ming

    2013-09-01

    Oocyte-secreted factors (OSFs) maintain the low incidence of cumulus cell apoptosis. In this report, we described that the presence of oocytes suppressed the expression of proapoptotic protein BCL-2-interacting mediator of cell death-extra long (BIMEL) in porcine cumulus cells. Atretic (terminal deoxynucleotidyl transferase dUTP nick end labeling-positive) cumulus cells strongly expressed BIMEL protein. The healthy cumulus- oocyte complex exhibited a low BIMEL expression in cumulus cell while the removal of oocyte led to an about 2.5-fold (P < 0.5) increased expression in oocytectomized complex (OOX). Coculturing OOXs with denuded oocytes decreased BIMEL expression to the normal level. The similar expression pattern could also be achieved in OOXs treated with exogenous recombinant mouse growth differentiation factor 9 (GDF9), a well-characterized OSF. This inhibitory action of GDF9 was prevented by the addition of a phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002. Luciferase assay further demonstrated that BIM gene expression was forkhead box O3a (FOXO3a)-dependent because mutation of FOXO3a-binding site on the BIM promoter inhibited luciferase activities. Moreover, the activity of BIM promoter encompassing the FOXO3a-binding site could be regulated by GDF9. Additionally, we found that GDF9 elevated the levels of phosphorylated AKT and FOXO3a, and this process was independent of the SMAD signal pathway. Taken together, we concluded that OSFs, particularly GDF9, maintained the low level of BIMEL expression in cumulus cell through activation of the PI3K/FOXO3a pathway.

  13. IRES-mediated translation of the pro-apoptotic Bcl2 family member PUMA.

    PubMed

    Shaltouki, Atossa; Harford, Terri J; Komar, Anton A; Weyman, Crystal M

    2013-01-01

    The proapoptotic Bcl-2 family member PUMA is a critical regulator of apoptosis. We have previously shown that PUMA plays a pivotal role in the apoptosis associated with skeletal myoblast differentiation and that a MyoD-dependent mechanism is responsible for the increased expression of PUMA in these cells. Herein, we report that the increased expression of PUMA under these conditions involves regulation at the level of translation. Specifically, we have found that the increase in PUMA protein levels occurs under conditions of decreased total protein synthesis, eIF2-alpha phosphorylation and hypophosphorylation of eIF4E-BP, suggesting that PUMA translation is proceeding via an alternative initiation mechanism. Polyribosome analysis of PUMA mRNA further corroborated this suggestion. A combination of in vitro and ex vivo (cellular) approaches has provided evidence suggesting that PUMA mRNA 5'UTR harbors an Internal Ribosome Entry Site (IRES) element. Using mono- and bi-cistronic reporter constructs, we have delineated an mRNA fragment that allows for cap-independent translation in vitro and ex vivo (in skeletal myoblasts) in response to culture in differentiation media (DM), or in response to treatment with the DNA-damaging agent, etoposide. This mRNA fragment also supports translation in HeLa and 293T cells. Thus, our data has revealed a novel IRES-mediated regulation of PUMA expression in several cell types and in response to several stimuli. These findings contribute to our understanding and potential manipulation of any developmental or therapeutic scenario involving PUMA.

  14. Expression of Bcl-2 family proteins and associated clinicopathologic factors predict survival outcome in patients with oral squamous cell carcinoma.

    PubMed

    Camisasca, Danielle Resende; Honorato, Júlia; Bernardo, Vagner; da Silva, Licínio Esmeraldo; da Fonseca, Eliene Carvalho; de Faria, Paulo Antônio Silvestre; Dias, Fernando Luiz; Lourenço, Simone de Queiroz Chaves

    2009-03-01

    The aims of this study were to assess the expression levels of three proteins involved in apoptosis--Bcl-2, Bcl-X, and Bax--and evaluate their relationship with clinicopathologic features and survival in oral squamous cell carcinoma (OSCC). Immunohistochemistry was used to evaluate protein expression in 53 primary OSCCs treated by radical surgery with free margins at a single institution in 1999. Histologic specimens were graded and analyzed for perineural invasion, lymphocytic infiltrate, and pattern of invasion. Digital image analysis was performed to quantify immunostaining. Survival was analyzed using the Kaplan-Meier method and Cox's proportional hazard model. Cancer-specific 5-year survival (CSS) was 61% (56% overall survival (OS), and 51% disease-free interval (DFI)). Kaplan-Meier analysis identified pathologic stage (p=0.0007, log-rank test, OS), negative nodes status (pN) (p<0.0001, log-rank test, OS), presence of lymphocytic infiltrate (p=0.0084, log-rank test, OS), and high Bax expression (p=0.025, log-rank test, OS) to each be associated with both better OS and CSS. Tongue tumors (p=0.0179, log-rank test), worst pattern of invasion (p=0.0293, log-rank test), lack of lymphocytic infiltrate (p=0.0328, log-rank test), perineural invasion (p=0.0448, log-rank test), poorly differentiated tumors (p=0.0318, log-rank test), and low Bcl-X expression (p=0.044, log-rank test) were all associated with a low DFI. Cox regression found pN, lymphocytic infiltrate, and Bax expression to be independent prognostic factors for OS and CSS, whereas lymphocytic response and tongue tumors were predictors of DFI. Bcl-2 expression emerged as an independent marker of favorable CSS. Lymphocytic infiltrate was the most meaningful histopathologic parameter in survival analysis, whereas expression of Bcl-2 family members seems to be an important marker of a favorable prognosis in OSCC.

  15. Expression of p63 and Bcl-2 in Malignant Thyroid Tumors and their Correlation with other Diagnostic Immunocytochemical Markers

    PubMed Central

    Jain, Shyama; Khurana, Nita; Kakar, Arun Kumar

    2016-01-01

    Introduction Bcl-2 is a marker recently studied in thyroid tumours and proposed to have prognostic significance. p63 is expressed in a proportion of papillary thyroid carcinoma cases and may have a role in tumour progression. Aim To study expression of Bcl2 and p63 in thyroid tumours and correlation of Bcl-2 with diagnostic markers including Thyroglobulin, Calcitonin and Carcinoembryonic antigen. Materials and Methods Cytology smears of 35 cases of thyroid cancer were studied over a period of 18 months. In 20 cases histopathology was available. Immunocytochemistry for Bcl-2 and p63 was done, and diagnostic markers were applied as and when required. Results p63 showed focal nuclear expression in 46.1% of papillary thyroid carcinoma cases, and was negative in all other tumours. Bcl-2 was positive in 88.9% of follicular carcinomas, 100% of papillary carcinomas and 83.3% of medullary carcinoma cases, and showed focal weak expression in 40% of Anaplastic Carcinoma (ATC) cases, thereby signifying down regulation (p-value = 0.001). There was significant down regulation of Thyroglobulin (Tg) in ATC vs well differentiated follicular derived tumours (p-value ≤ 0.016). Positive correlation was noted between expression of Bcl-2 and Calcitonin (0.93) and Bcl-2 and Carcinoembryonic Antigen (CEA) (0.89), and weak positive correlation (0.65) between Tg and Bcl-2. Conclusion Bcl-2 is downregulated in anaplastic carcinomas as compared to well differentiated thyroid tumours, and shows correlation with differentiation associated tumour antigens. Thus, loss of Bcl-2 was associated with loss of differentiation in thyroid tumours. Anaplastic carcinoma as such is associated with worse prognosis and loss of Bcl-2 may be partly responsible for the same. p63 is specific but less sensitive marker for PTC. Further studies are required to determine the role of Bcl-2 and p63 in thyroid tumours. PMID:27630849

  16. Expanding the Cancer Arsenal with Targeted Therapies: Disarmament of the Antiapoptotic Bcl-2 Proteins by Small Molecules.

    PubMed

    Yap, Jeremy L; Chen, Lijia; Lanning, Maryanna E; Fletcher, Steven

    2017-02-09

    A hallmark of cancer is the evasion of apoptosis, which is often associated with the upregulation of the antiapoptotic members of the Bcl-2 family of proteins. The prosurvival function of the antiapoptotic Bcl-2 proteins is manifested by capturing and neutralizing the proapoptotic Bcl-2 proteins via their BH3 death domains. Accordingly, strategies to antagonize the antiapoptotic Bcl-2 proteins have largely focused on the development of low-molecular-weight, synthetic BH3 mimetics ("magic bullets") to disrupt the protein-protein interactions between anti- and proapoptotic Bcl-2 proteins. In this way, apoptosis has been reactivated in malignant cells. Moreover, several such Bcl-2 family inhibitors are presently being evaluated for a range of cancers in clinical trials and show great promise as new additions to the cancer armamentarium. Indeed, the selective Bcl-2 inhibitor venetoclax (Venclexta) recently received FDA approval for the treatment of a specific subset of patients with chronic lymphocytic leukemia. This review focuses on the major developments in the field of Bcl-2 inhibitors over the past decade, with particular emphasis on binding modes and, thus, the origins of selectivity for specific Bcl-2 family members.

  17. miR-143 Induces the Apoptosis of Prostate Cancer LNCap Cells by Suppressing Bcl-2 Expression

    PubMed Central

    Ma, Zhiwei; Luo, Yizhao; Qiu, Mingxing

    2017-01-01

    Background Prostate cancer has become a serious threat to the life of patients. microRNAs are small non-coding RNA molecules that regulate the growth and apoptosis of cells. We aimed to investigate the regulation and mechanism of microRNA (miR-143) in the proliferation and apoptosis of prostate cancer LNCap cells. Material/Methods miR-143 and control scramble miRNA were synthesized and respectively transfected into LNCap cells. The proliferation and apoptosis were detected by MTT assay, flow cytometry, and caspase-3 activity assay. The intracellular expression of Bcl-2 was determined by Western blot. Further, LNCap cells were transfected with small interfering RNA (siRNA) targeting Bcl-2 (siBcl-2) or plasmid expressing Bcl-2, followed by transfection of miR-143 or control miRNA. Bcl-2 expression was detected by Western blot, and cell apoptosis was measured by caspase-3 activity assay. Results Transfection of miR-143 significantly inhibited the proliferation of LNCap cells (P=0.0073), increased the percentage of externalized phosphatidylserine (P=0.0042), activated the caspase-3 (P=0.0012), and decreased the expression of Bcl-2 (P=0.012) when compared with the control miRNA group. The expression of Bcl-2 was significantly reduced after siBcl-2 transfection. The apoptosis in the siBcl-2+miR-143 group was significantly increased compared with that in the miR-143 group (P=0.036), whereas there was no significant difference in the apoptosis between the siBcl-2+miRNA and miRNA groups. The expression of Bcl-2 was obviously higher after the transfection of Bcl-2-expressing plasmid. The apoptosis in Bcl-2+miR-143 group was significantly reduced compared with the miR-143 group (P=0.031), whereas no significant difference in the apoptosis was detected between the miRNA and Bcl-2+miRNA groups. Conclusions Transfection of miR-143 induces the apoptosis of prostate cancer LNCap cells by down-regulating Bcl-2 expression, suggesting that Bcl-2 might be a potential therapeutic

  18. TDB protects vascular endothelial cells against oxygen-glucose deprivation/reperfusion-induced injury by targeting miR-34a to increase Bcl-2 expression

    PubMed Central

    Liao, Li-Xi; Zhao, Ming-Bo; Dong, Xin; Jiang, Yong; Zeng, Ke-Wu; Tu, Peng-Fei

    2016-01-01

    Prolonged ischemia can result in apoptotic death of vascular endothelial cells and lead to ischemic vascular diseases including vascular dementia, arteriosclerosis and brain oedema. Finding protective strategies to prevent this is therefore an urgent mission. Recent studies have shown that dysregulation of microRNAs (miRNAs) can lead to imbalance of Bcl-2 family proteins and mitochondrial dysfunction, leading to further damage of vascular cells under ischemic conditions. However, whether miRNAs can be used as a drug target for treating vascular diseases is not fully understood. In this study, we observed that the natural product 2,4,5-trihydroxybenzaldehyde (TDB) could effectively inhibit vascular cell apoptosis following oxygen-glucose deprivation/reperfusion (OGD/R) by maintaining mitochondrial membrane potential (MMP) and suppressing activation of the mitochondria-dependent caspase-9/3 apoptosis pathway. Furthermore, we identified miR-34a, a crucial negative regulator of Bcl-2, as a target for the protective effect of TDB on vascular cells. TDB-induced suppression of miR-34a resulted in a significant upregulation of Bcl-2 protein, MMP maintenance, and the survival of vascular cells following OGD/R. Our findings suggest that targeting miR-34a with the natural product TDB may provide a novel strategy for the treatment of ischemic vascular injuries, and demonstrate the therapeutic potential in targeting miRNAs using appropriate small molecules. PMID:27885275

  19. Loss of PUMA (BBC3) does not prevent thrombocytopenia caused by the loss of BCL-XL (BCL2L1).

    PubMed

    Delbridge, Alex R D; Chappaz, Stephane; Ritchie, Matthew E; Kile, Benjamin T; Strasser, Andreas; Grabow, Stephanie

    2016-09-01

    Apoptosis is required to maintain tissue homeostasis in multicellular organisms. Platelets, the anucleate cells that are essential for blood clotting, are a prime example. Their brief life span in the circulation is regulated by the intrinsic apoptosis pathway. Pro-survival BCL-XL (also termed BCL2L1) is essential for platelet viability. It functions to restrain the pro-apoptotic BCL-2 family members BAK (also termed BAK1) and BAX, the essential mediators of intrinsic apoptosis. Genetic deletion or pharmacological inhibition of BCL-XL results in thrombocytopenia. Conversely, deletion of BAK in platelets doubles their circulating life span. However, what triggers platelet apoptosis in vivo remains unclear. The pro-apoptotic BH3-only proteins are essential for initiating apoptosis in nucleated cells, and there is some evidence to suggest they also play a role in platelet biology. We investigated whether PUMA (also termed BBC3), a potent BH3-only protein that can inhibit all pro-survival BCL-2 family members as well as directly activate BAX, regulates the death of platelets. Surprisingly, loss of PUMA had no impact on the loss of platelets caused by loss of BCL-XL. It therefore remains to be established whether other BH3-only proteins play a critical role in induction of apoptosis in platelets or whether their death is controlled solely by the interactions between BCL-XL with BAK and BAX.

  20. Expression levels of the BAK1 and BCL2 genes highlight the role of apoptosis in age-related hearing impairment

    PubMed Central

    Falah, Masoumeh; Najafi, Mohammad; Houshmand, Massoud; Farhadi, Mohammad

    2016-01-01

    Age-related hearing impairment (ARHI) is a progressive and a common sensory disorder in the elderly and will become an increasingly important clinical problem given the growing elderly population. Apoptosis of cochlear cells is an important factor in animal models of ARHI. As these cells cannot regenerate, their loss leads to irreversible hearing impairment. Identification of molecular mechanisms can facilitate disease prevention and effective treatment. In this study, we compared the expression of the genes BAK1 and BCL2 as two arms of the intrinsic apoptosis pathway between patients with ARHI and healthy subjects. ARHI and healthy subjects were selected after an ear nose throat examination, otoscopic investigation, and pure tone audiometry. RNA was extracted from peripheral blood samples, and relative gene expression levels were measured using quantitative real-time polymerase chain reaction. BAK1 and the BAK1/BCL2 ratio were statistically significantly upregulated in the ARHI subjects. The BAK1/BCL2 ratio was positively correlated with the results of the audiometric tests. Our results indicate that BAK-mediated apoptosis may be a core mechanism in the progression of ARHI in humans, similar to finding in animal models. Moreover, the gene expression changes in peripheral blood samples could be used as a rapid and simple biomarker for early detection of ARHI. PMID:27555755

  1. Cobalt chloride induces apoptosis and zinc chloride suppresses cobalt-induced apoptosis by Bcl-2 expression in human submandibular gland HSG cells.

    PubMed

    Akita, Kazumi; Okamura, Hirohiko; Yoshida, Kaya; Morimoto, Hiroyuki; Ogawa-Iyehara, Hiroaki; Haneji, Tatsuji

    2007-10-01

    To determine the effects of cobalt chloride on human submandibular gland cells, HSG cells were exposed to various concentrations of cobalt chloride. Cobalt chloride induced cytotoxicity and cell death in HSG cells as determined by phase-contrast microscopy and WST-1 cell viability assay. By using the Hoechst 33342 staining, marked nuclear condensation and fragmentation of chromatin were observed in cobalt chloride-treated cells. Cobalt chloride induced DNA ladder formation in HSG cells in both dose- and time-dependent manner with maximal effect at a concentration of 0.5 mM and 48 h, respectively. Cobalt chloride inhibited the expression of both Bcl-2 protein and mRNA in dose- and time-dependent manner. Zinc chloride recovered the cobalt-suppressed Bcl-2 expression and protected against cobalt-induced apoptosis in HSG cells. Our results show that the pathway of the apoptosis in HSG cells is regulated by cobalt chloride and zinc chloride. Our results also indicate that cobalt-induced apoptotic steps in HSG cells are related to the production of Bcl-2 protein.

  2. Arctigenin, a dietary phytoestrogen, induces apoptosis of estrogen receptor-negative breast cancer cells through the ROS/p38 MAPK pathway and epigenetic regulation.

    PubMed

    Hsieh, Chia-Jung; Kuo, Po-Lin; Hsu, Ying-Chan; Huang, Ya-Fang; Tsai, Eing-Mei; Hsu, Ya-Ling

    2014-02-01

    This study investigates the anticancer effect of arctigenin (ATG), a natural lignan product of Arctium lappa L., in human breast cancer MDA-MB-231 cells. Results indicate that ATG inhibits MDA-MB-231 cell growth by inducing apoptosis in vitro and in vivo. ATG triggers the mitochondrial caspase-independent pathways, as indicated by changes in Bax/Bcl-2 ratio, resulting in AIF and EndoG nuclear translocation. ATG increased cellular reactive oxygen species (ROS) production by increasing p22(phox)/NADPH oxidase 1 interaction and decreasing glutathione level. ATG clearly increases the activation of p38 MAPK, but not JNK and ERK1/2. Antioxidant EUK-8, a synthetic catalytic superoxide and hydrogen peroxide scavenger, significantly decreases ATG-mediated p38 activation and apoptosis. Blocking p38 with a specific inhibitor suppresses ATG-mediated Bcl-2 downregulation and apoptosis. Moreover, ATG activates ATF-2, a transcription factor activated by p38, and then upregulates histone H3K9 trimethylation in the Bcl-2 gene promoter region, resulting in Bcl-2 downregulation. Taken together, the results demonstrate that ATG induces apoptosis of MDA-MB-231 cells via the ROS/p38 MAPK pathway and epigenetic regulation of Bcl-2 by upregulation of histone H3K9 trimethylation.

  3. The Vaccinia Virus-Encoded Bcl-2 Homologues Do Not Act as Direct Bax Inhibitors

    PubMed Central

    Postigo, Antonio

    2012-01-01

    Many viruses, including members of several poxvirus genera, encode inhibitors that block apoptosis by simultaneously binding the proapoptotic Bcl-2 proteins Bak and Bax. The Orthopoxvirus vaccinia virus encodes the Bcl-2-like F1 protein, which sequesters Bak but not Bax. However, N1, a potent virulence factor, is reported to be antiapoptotic and to interact with Bax. Here we investigated whether vaccinia virus inhibits Bak/Bax-dependent apoptosis via the cooperative action of F1 and N1. We found that Western Reserve (WR) and ΔN1L viruses inhibited drug- and infection-induced apoptosis equally. Meanwhile, infections with ΔF1L or ΔN1L/F1L virus resulted in similar levels of Bax activation and apoptosis. Outside the context of infection, N1 did not block drug- or Bax-induced cell death or interact with Bax. In addition to F1 and N1, vaccinia virus encodes further structural homologs of Bcl-2 proteins that are conserved in orthopoxviruses, including A46, A52, B14, C1, C6, C16/B22, K7, and N2. However, we found that these do not associate with Bax or inhibit drug-induced cell death. Based on our findings that N1 is not an antiapoptotic protein, we propose that the F1 orthologs represent the only orthopoxvirus Bcl-2 homolog to directly inhibit the Bak/Bax checkpoint. PMID:22013032

  4. [Influence of TIEG1 on apoptosis of HL-60 cells and expression of Bcl-2/Bax].

    PubMed

    Yao, Kun; Yang, Ying; Hu, Rong; Miao, Miao; Liao, Ai-Jun; Yang, Wei; Liu, Zhuo-Gang

    2013-06-01

    This study was aimed to investigate the influence of TIEG1 on apoptosis of HL-60 cells and the expression of Bcl-2/Bax. Different concentration of TIEG1 were used to treat HL-60 cells, the cell growth inhibition rate was detected by MTT method. After treating HL-60 cells with 12.03 ng/ml TIEG1, cell apoptosis was detected with flow cytometry. Bcl-2 and Bax was detected with RT-PCR. The results showed that TIEG1 had inhibitory effect on HL-60 cell proliferation, and in time-and dose-dependent manners. The more obvious inhibitory effect was observed in HL-60 cells treated with TIEG1 of 12.03 ng/ml. During the course of cell apoptosis, Bax expression increased, but Bcl-2 expression decreased (P < 0.05). It is concluded that TIEG1 inhibits HL-60 cell proliferation and induces apoptosis in time and dose-dependent manners. During the course of HL-60 cells apoptosis induced by TIEG1, Bcl-2/Bax are associated with HL-60 cell apoptosis induced by TIEG1.

  5. Toxocara-induced hepatic inflammation: immunohistochemical characterization of lymphocyte subpopulations and Bcl-2 expression.

    PubMed

    Othman, Ahmad A; Ashour, Dalia S; Mohamed, Dareen A

    2013-05-01

    Toxocariasis is a soil-transmitted helminthic disease due to infection of humans by larvae of Toxocara canis (T. canis). It is one of the most commonly reported zoonotic infections in the world. The aim of this study was to characterize the key immune cells and activity of Bcl-2 in hepatic inflammation during the course of experimental infection by T. canis. Mice experimentally infected with T. canis were divided into two groups: mice with primary infection by Toxocara, and those infected after sensitization by Toxocara excretory-secretory antigen. CD4+, CD8+, and Bcl-2-expressing T lymphocytes were identified in the liver by immunohistochemistry at different durations post-infection. Recruitment of both CD4+ and CD8+ T lymphocytes within the inflammatory reaction in the liver was observed, with difference in count and localization. These cells were detected within and around Toxocara-induced granulomas as well as in isolated inflammatory foci in the portal tracts or within the hepatic parenchyma. The antiapoptotic protein Bcl-2 showed no significant change at different periods post-infection. On the other hand, immunization of mice with Toxocara excretory-secretory antigen prior to experimental infection caused earlier and more pronounced recruitment of CD4+ and CD8+ T cells to the liver and enhanced expression of Bcl-2. Moreover, CD8+ cells became more diffuse within the inflammatory infiltrate. These results suggest a dynamic change in key immune cells according to the duration of infection as well as the immune status of the host.

  6. Meiotic recombination between yeast artificial chromosomes yields a single clone containing the entire BCL2 protooncogene.

    PubMed Central

    Silverman, G A; Green, E D; Young, R L; Jockel, J I; Domer, P H; Korsmeyer, S J

    1990-01-01

    The common translocation found in human follicular lymphoma, t(14;18)(q32;q21), results in deregulation of the BCL2 protoonocogene. The isolation of the intact gene would provide an essential substrate to analyze the molecular basis of this malignancy. Pulsed-field gel electrophoresis suggested that this three-exon gene was several hundred kilobases (kb) long. Therefore, a library of yeast artificial chromosome (YAC) clones was screened to isolate the intact BCL2 gene. Two clones, yA85B6 (200 kb) and yB206A6 (700 kb), were isolated by using polymerase chain reaction (PCR) assays specific for exon I/II and exon III, respectively. However, neither YAC contained the entire BCL2 locus. Since the two YACs were found to overlap by 60 kb, we sought to take advantage of the high recombination frequency in yeast and induce physical recombination between the two clones. Cells containing each YAC were mated and induced to undergo meiotic division and sporulation. Analysis of the resulting tetrads revealed a spore containing a single recombinant YAC of 800 kb. PCR assays and Southern blotting demonstrated that this recombined YAC contained the entire approximately 230-kb BCL2 gene. Furthermore, probe order was conserved and there was no evidence of overt rearrangements or deletions. These results indicate the feasibility of reconstructing large genomic segments with overlapping YAC clones to study genes spanning hundreds of kilobases. Images PMID:2263642

  7. Cannabinoids Regulate Bcl-2 and Cyclin D2 Expression in Pancreatic β Cells

    PubMed Central

    Kim, Jung Seok; Rho, Jun Gi; Shin, Jung Jae; Song, Woo Keun; Lee, Eun Kyung; Egan, Josephine M.; Kim, Wook

    2016-01-01

    Recent reports have shown that cannabinoid 1 receptors (CB1Rs) are expressed in pancreatic β cells, where they induce cell death and cell cycle arrest by directly inhibiting insulin receptor activation. Here, we report that CB1Rs regulate the expression of the anti-apoptotic protein Bcl-2 and cell cycle regulator cyclin D2 in pancreatic β cells. Treatment of MIN6 and βTC6 cells with a synthetic CB1R agonist, WIN55,212–2, led to a decrease in the expression of Bcl-2 and cyclin D2, in turn inducing cell cycle arrest in G0/G1 phase and caspase-3-dependent apoptosis. Additionally, genetic deletion and pharmacological blockade of CB1Rs after injury in mice led to increased levels of Bcl-2 and cyclin D2 in pancreatic β cells. These findings provide evidence for the involvement of Bcl-2 and cyclin D2 mediated by CB1Rs in the regulation of β-cell survival and growth, and will serve as a basis for developing new therapeutic interventions to enhance β-cell function and growth in diabetes. PMID:26967640

  8. Chemoprevention of intestinal tumorigenesis by nabumetone: induction of apoptosis and Bcl-2 downregulation.

    PubMed

    Roy, H K; Karoski, W J; Ratashak, A; Smyrk, T C

    2001-05-18

    Treatment of MIN mice with the nonsteroidal anti-inflammatory drug, nabumetone, resulted in a dose-dependent suppression of intestinal tumorigenesis. In both the uninvolved MIN mouse colonic epithelium and HT-29 colon cancer cells, nabumetone downregulated the anti-apoptotic protein, Bcl-2, with concomitant induction of apoptosis, suggesting a potential mechanism for colon cancer chemoprevention.

  9. Neuroendocrine Differentiation in Breast Cancer: Clinicopathological Significance of Bcl-2 Positive Solid Papillary Carcinoma

    PubMed Central

    Okubo, Takuji; Okubo, Yoshimi; Ishiwatari, Takao

    2016-01-01

    Solid papillary carcinoma (SPC) is considered a rare malignant breast tumor. Maluf and Koerner first reported this disease entity as a special type of ductal carcinoma in situ with several characteristic histopathological features, including low-grade cellular atypia, intracellular or extracellular mucin deposition, and solid papillary growth pattern, as well as neuroendocrine differentiation. The present paper describes a case of SPC with bcl-2 expression, which is known as a marker for malignancy of neuroendocrine tumors. Interestingly, despite bcl-2 expression being a poor prognostic indicator of neuroendocrine tumors, the patient with this tumor has achieved long-term survival (approximately 6 years) at the time of writing this report. Because previous investigators reported that bcl-2 expression might play a role in the inhibition of the development of breast cancer, we suggest that bcl-2 expression might reflect a good prognosis in patients with SPC, rather than being a poor prognostic indicator, as it is in several types of neuroendocrine tumor. However, to confirm this hypothesis, further investigation is required. PMID:28105053

  10. Connexin 36 and Rod Bipolar Cell Independent Rod Pathways Drive Retinal Ganglion Cells and Optokinetic Reflexes

    PubMed Central

    Cowan, Cameron S.; Abd-El-Barr, Muhammad; van der Heijden, Meike; Lo, Eric M.; Paul, David; Bramblett, Debra E.; Lem, Janis; Simons, David L.; Wu, Samuel M.

    2016-01-01

    Rod pathways are a parallel set of synaptic connections which enable night vision by relaying and processing rod photoreceptor light responses. We use dim light stimuli to isolate rod pathway contributions to downstream light responses then characterize these contributions in knockout mice lacking rod transducin-α (Trα), or certain pathway components associated with subsets of rod pathways. These comparisons reveal that rod pathway driven light sensitivity in retinal ganglion cells (RGCs) is entirely dependent on Trα, but partially independent of connexin 36 (Cx36) and rod bipolar cells. Pharmacological experiments show that rod pathway-driven and Cx36-independent RGC ON responses are also metabotropic glutamate receptor 6-dependent. To validate the RGC findings in awake, behaving animals we measured optokinetic reflexes (OKRs), which are sensitive to changes in ON pathways. Scotopic OKR contrast sensitivity was lost in Trα−/− mice, but indistinguishable from controls in Cx36−/− and rod bipolar cell knockout mice. Mesopic OKRs were also altered in mutant mice: Trα−/− mice had decreased spatial acuity, rod BC knockouts had decreased sensitivity, and Cx36−/− mice had increased sensitivity. These results provide compelling evidence against the complete Cx36 or rod BC dependence of night vision's ON component. Further, the findings suggest the parallel nature of rod pathways provides considerable redundancy to scotopic light sensitivity but distinct contributions to mesopic responses through complicated interactions with cone pathways. PMID:26718442

  11. Prognostic significance of COX-2 expression and correlation with Bcl-2 and VEGF expression, microvessel density, and clinical variables in classical Hodgkin lymphoma.

    PubMed

    Koh, Young Wha; Park, Chansik; Yoon, Dok Hyun; Suh, Cheolwon; Huh, Jooryung

    2013-08-01

    Vascular endothelial growth factor (VEGF) and cyclooxygenase-2 (COX-2) play important roles in tumor angiogenesis. Recent reports found that COX-2 expression had prognostic value in classical Hodgkin lymphoma (cHL). The purpose of this study was to measure the expression of COX-2, B-cell lymphoma-2 (Bcl-2), VEGF, and CD31 and assess their prognostic significance and potential correlation with clinical variables in cHL. A total of 167 cHL specimens were evaluated retrospectively by immunohistochemical methods for COX-2, Bcl-2, and VEGF expression and for CD31 to measure the microvessel density (MVD). Correlations between COX-2, Bcl-2, VEGF, MVD, and clinicopathologic factors were assessed, and prognostic significance was determined. COX-2, Bcl-2, and VEGF were expressed in 27.5%, 8.3%, and 33.5% of the specimens, respectively. A positive correlation was found between COX-2 and VEGF expression (P<0.001). The MVD was significantly higher in tumors positive for both COX-2 and VEGF compared with that in tumors negative for both markers (P=0.047). COX-2 expression was associated with a lower overall survival rate (P=0.015). High MVD was associated with a lower event-free survival rate (P=0.014). COX-2 was an independent prognostic factor for overall survival on multivariate analysis (P=0.013). COX-2 and VEGF correlated with angiogenesis and tumor progression in cHL. The findings support targeting COX-2 as a potential new therapeutic approach in cHL.

  12. Genetic dissimilarity between primary colorectal carcinomas and their lymph node metastases: ploidy, p53, bcl-2, and c-myc expression--a pilot study.

    PubMed

    Zalata, Khaled Refaat; Elshal, Mohamed Farouk; Foda, Abd AlRahman Mohammad; Shoma, Ashraf

    2015-08-01

    The current paradigm of metastasis proposes that rare cells within primary tumors acquire metastatic capability via sequential mutations, suggesting that metastases are genetically dissimilar from their primary tumors. This study investigated the changes in the level of expression of a well-defined panel of cell proliferation, differentiation, and apoptosis markers between the primary colorectal cancer (CRC) and the corresponding synchronous lymph node (LN) metastasis from the same patients. DNA flow cytometry and immunostaining of p53, bcl-2, and c-myc were carried out on 36 cases of CRC radical resection specimens with their corresponding LN metastases. There was very low probability that the histological patterns of primary tumors and LN metastases are independent (p < 0.001). Metastatic tumors were significantly more diffusely positive for p53 than the primary tumors (p < 0.001). Conversely, primary tumors were significantly more diffusely positive for c-myc than metastatic tumors (p = 0.011). No significant difference was found between the LNs and the primary tumors in bcl-2 positivity (p = 0.538) and DNA aneuploidy (p = 0.35), with a tendency towards negative bcl-2 and less aneuploidy in LN metastases than primary tumors. In conclusion, LN metastatic colorectal carcinomas have a tendency of being less differentiated, with a higher incidence of diffuse p53 staining, lower incidence of bcl-2 staining, and less aneuploidy in comparison to their primary counterparts suggesting a more aggressive biological behavior, which could indicate the necessity for more aggressive adjuvant therapy.

  13. Bifurcation of the endocytic pathway into Rab5-dependent and -independent transport to the vacuole

    NASA Astrophysics Data System (ADS)

    Toshima, Junko Y.; Nishinoaki, Show; Sato, Yoshifumi; Yamamoto, Wataru; Furukawa, Daiki; Siekhaus, Daria Elisabeth; Sawaguchi, Akira; Toshima, Jiro

    2014-03-01

    The yeast Rab5 homologue, Vps21p, is known to be involved both in the vacuolar protein sorting (VPS) pathway from the trans-Golgi network to the vacuole, and in the endocytic pathway from the plasma membrane to the vacuole. However, the intracellular location at which these two pathways converge remains unclear. In addition, the endocytic pathway is not completely blocked in yeast cells lacking all Rab5 genes, suggesting the existence of an unidentified route that bypasses the Rab5-dependent endocytic pathway. Here we show that convergence of the endocytic and VPS pathways occurs upstream of the requirement for Vps21p in these pathways. We also identify a previously unidentified endocytic pathway mediated by the AP-3 complex. Importantly, the AP-3-mediated pathway appears mostly intact in Rab5-disrupted cells, and thus works as an alternative route to the vacuole/lysosome. We propose that the endocytic traffic branches into two routes to reach the vacuole: a Rab5-dependent VPS pathway and a Rab5-independent AP-3-mediated pathway.

  14. MicroRNA-184 Modulates Doxorubicin Resistance in Osteosarcoma Cells by Targeting BCL2L1

    PubMed Central

    Lin, Bo-chuan; Huang, Dong; Yu, Chao-qun; Mou, Yong; Liu, Yuan-hang; Zhang, Da-wei; Shi, Feng-jun

    2016-01-01

    Background Early metastasis of osteosarcoma (OS) is highly lethal and responds poorly to drug and radiation therapies. MicroRNAs (miRNAs) are a class of small noncoding RNAs that modulate gene expression at the post-transcriptional level. However, the detailed functions of specific miRNAs are not entirely understood. The aim of the present study was to investigate the role of miR-184 as a mediator of drug resistance in human osteosarcoma. Material/Methods qRT-PCR was used to analyze the expression level of miR-184 in OS cell line U-2 OS and MG-63 treated with doxorubicin. MiR-184 agomir or miR-184 antagomir was transferred into cells to regulated miR-184. The target of miR-184 was predicted by TargetScan and confirmed by luciferase reporter assay. Bcl-2-like protein 1 (BCL2L1) expression was detected by Western blot. Cell apoptosis was determined by Annexin V staining and analysis by flow cytometry. Results Doxorubicin induced time-dependent expression of miR-184 in OS cell line U-2 OS and MG-63. Luciferase reporter assay identified BCL2L1 as the direct target gene of miR-184. Furthermore, doxorubicin reduced BCL2L1 expression, which was reversed by miR-184 overexpression and further decreased by miR-184 inhibition in OS cells. In addition, miR-184 agomir reduced doxorubicin-induced cell apoptosis, whereas miR-184 antagomir enhanced apoptosis in OS cells, suggesting that up-regulation of miR-184 contributes to chemoresistance of the OS cell line. Conclusions Our data show that miR-184 was up-regulated in OS patients treated with doxorubicin therapy and leads to poor response to drug therapy by targeting BCL2L1. PMID:27222034

  15. Effect of bcl-2 overexpression in mice on ovotoxicity caused by 4-vinylcyclohexene

    SciTech Connect

    Flaws, Jodi A.; Marion, Samuel L.; Miller, Kimberly P.; Christian, Patricia J.; Babus, Janice K.; Hoyer, Patricia B. . E-mail: hoyer@u.arizona.edu

    2006-08-15

    The occupational chemical 4-vinylcyclohexene (VCH) destroys small preantral ovarian follicles in mice following repeated daily dosing. The cell survival gene bcl-2 is thought to protect against follicular death during embryogenesis because primordial follicle numbers in newborn bcl-2 overexpressing (OE) mice are greater than in wild-type (WT) controls. Thus, this study was designed to determine if overexpression of bcl-2 protects against VCH-induced follicle loss during embryonic development. Pregnant bcl-2 OE or WT mice were dosed (p.o.) daily with VCH (500 mg/kg) or sesame oil (vehicle control) on days 8-18 of pregnancy. Ovaries were collected from moms and female pups on pup postnatal day (PND) 8. Nonpregnant OE and WT females were also treated with VCH (500 mg/kg p.o.) or vehicle and evaluated in the same manner. As previously reported, ovaries from PND8 OE female pups contained 50% more primordial follicles than WT pups (P < 0.05). Unlike WT pups, relative to vehicle controls, in utero exposure to VCH resulted in a reduction in primordial (25% of control), primary (38% of control), and secondary (33% of control) follicles in ovaries of OE pups (P < 0.05). VCH had no significant effect on follicle numbers in OE or WT moms. Conversely, in nonpregnant adults, VCH did not affect WT mice but caused loss of primordial (55% of control), primary (51% of control), and secondary (69% of control) follicles in OE mice (P < 0.05). These results demonstrate that bcl-2 overexpression does not protect against, but instead increases susceptibility to VCH-induced follicle loss in transplacentally exposed or in nonpregnant mice.

  16. Characterization of apoptosis and autophagy through Bcl-2 and Beclin-1 immunoexpression in gestational trophoblastic disease

    PubMed Central

    Wargasetia, Teresa Liliana; Shahib, Nurhalim; Martaadisoebrata, Djamhoer; Dhianawaty, Diah; Hernowo, Bethy

    2015-01-01

    Background: The pathogenesis of Gestational Trophoblastic Disease (GTD) is not clearly known. Objective: In this study, immunoexpression of proteins Bcl-2 and Beclin-1 in trophoblastic lesions and normal trophoblastic tissue was conducted to study the mechanism of apoptotic and autophagic cell death that is expected to complete the study of GTD pathogenesis. Materials and Methods: Bcl-2 and Beclin-1 immunoexpression were studied on complete hydatidiform mole, partial hydatidiform mole, invasive mole, choriocarcinoma and normal placenta slides. Results: The average total scores of Bcl-2 immunoexpression had a decreasing value, starting from partial hydatidiform mole (3.09), complete hydatidiform mole (2.36), invasive mole (1.18) to choriocarcinoma (0) when compared to normal placenta (6). The results showed no significant difference in Beclin-1 immunoexpression total score between complete hydatidiform mole, partial hydatidiform mole and invasive mole, namely that the value of the average total score of Beclin-1 was low (2.27, 2.45 and 2.36), but on the contrary choriocarcinoma showed an increasing strong Beclin-1 expression with the average total score of 4.57. Conclusion: Bcl-2 expression decreases in line with the excessive proliferation of trophoblast cells in hydatidiform mole and leads to malignancy in invasive mole and choriocarcinoma. The decreased expression of Beclin-1 that leads to autophagy defects in complete hydatidiform mole, partial hydatidiform mole and invasive mole shows the role of autophagy as tumor suppressor, whereas strong Beclin-1 expression shows the survival role of autophagy in choriocarcinoma. The change of Bcl-2 activity as antiapoptosis and Beclin-1 as proautophagy plays a role in pathogenesis of GTD. PMID:26494988

  17. Genome-Wide Prediction and Validation of Peptides That Bind Human Prosurvival Bcl-2 Proteins

    PubMed Central

    DeBartolo, Joe; Taipale, Mikko; Keating, Amy E.

    2014-01-01

    Programmed cell death is regulated by interactions between pro-apoptotic and prosurvival members of the Bcl-2 family. Pro-apoptotic family members contain a weakly conserved BH3 motif that can adopt an alpha-helical structure and bind to a groove on prosurvival partners Bcl-xL, Bcl-w, Bcl-2, Mcl-1 and Bfl-1. Peptides corresponding to roughly 13 reported BH3 motifs have been verified to bind in this manner. Due to their short lengths and low sequence conservation, BH3 motifs are not detected using standard sequence-based bioinformatics approaches. Thus, it is possible that many additional proteins harbor BH3-like sequences that can mediate interactions with the Bcl-2 family. In this work, we used structure-based and data-based Bcl-2 interaction models to find new BH3-like peptides in the human proteome. We used peptide SPOT arrays to test candidate peptides for interaction with one or more of the prosurvival proteins Bcl-xL, Bcl-w, Bcl-2, Mcl-1 and Bfl-1. For the 36 most promising array candidates, we quantified binding to all five human receptors using direct and competition binding assays in solution. All 36 peptides showed evidence of interaction with at least one prosurvival protein, and 22 peptides bound at least one prosurvival protein with a dissociation constant between 1 and 500 nM; many peptides had specificity profiles not previously observed. We also screened the full-length parent proteins of a subset of array-tested peptides for binding to Bcl-xL and Mcl-1. Finally, we used the peptide binding data, in conjunction with previously reported interactions, to assess the affinity and specificity prediction performance of different models. PMID:24967846

  18. Biphasic onset of splenic apoptosis following hemorrhagic shock: critical implications for Bax, Bcl-2, and Mcl-1 proteins

    PubMed Central

    Hostmann, Arwed; Jasse, Kerstin; Schulze-Tanzil, Gundula; Robinson, Yohan; Oberholzer, Andreas; Ertel, Wolfgang; Tschoeke, Sven K

    2008-01-01

    Introduction The innate immune response to trauma hemorrhage involves inflammatory mediators, thus promoting cellular dysfunction as well as cell death in diverse tissues. These effects ultimately bear the risk of post-traumatic complications such as organ dysfunction, multiple organ failure, or adult respiratory distress syndrome. In this study, a murine model of resuscitated hemorrhagic shock (HS) was used to determine the apoptosis in spleen as a marker of cellular injury and reduced immune functions. Methods Male C57BL-6 mice were subjected to sham operation or resuscitated HS. At t = 0 hours, t = 24 hours, and t = 72 hours, mice were euthanized and the spleens were removed and evaluated for apoptotic changes via DNA fragmentation, caspase activities, and activation of both extrinsic and intrinsic apoptotic pathways. Spleens from untreated mice were used as control samples. Results HS was associated with distinct lymphocytopenia as early as t = 0 hours after hemorrhage without regaining baseline levels within the consecutive 72 hours when compared with sham and control groups. A rapid activation of splenic apoptosis in HS mice was observed at t = 0 hours and t = 72 hours after hemorrhage and predominantly confirmed by increased DNA fragmentation, elevated caspase-3/7, caspase-8, and caspase-9 activities, and enhanced expression of intrinsic mitochondrial proteins. Accordingly, mitochondrial pro-apoptotic Bax and anti-apoptotic Bcl-2 proteins were inversely expressed within the 72-hour observation period, thereby supporting significant pro-apoptotic changes. Solely at t = 24 hours, expression of the anti-apoptotic Mcl-1 protein shows a significant increase when compared with sham-operated and control animals. Furthermore, expression of extrinsic death receptors were only slightly increased. Conclusion Our data suggest that HS induces apoptotic changes in spleen through a biphasic caspase-dependent mechanism and imply a detrimental imbalance of pro- and anti

  19. Influenza A virus targets a cGAS-independent STING pathway that controls enveloped RNA viruses

    PubMed Central

    Holm, Christian K.; Rahbek, Stine H.; Gad, Hans Henrik; Bak, Rasmus O.; Jakobsen, Martin R.; Jiang, Zhaozaho; Hansen, Anne Louise; Jensen, Simon K.; Sun, Chenglong; Thomsen, Martin K.; Laustsen, Anders; Nielsen, Camilla G.; Severinsen, Kasper; Xiong, Yingluo; Burdette, Dara L.; Hornung, Veit; Lebbink, Robert Jan; Duch, Mogens; Fitzgerald, Katherine A.; Bahrami, Shervin; Mikkelsen, Jakob Giehm; Hartmann, Rune; Paludan, Søren R.

    2016-01-01

    Stimulator of interferon genes (STING) is known be involved in control of DNA viruses but has an unexplored role in control of RNA viruses. During infection with DNA viruses STING is activated downstream of cGAMP synthase (cGAS) to induce type I interferon. Here we identify a STING-dependent, cGAS-independent pathway important for full interferon production and antiviral control of enveloped RNA viruses, including influenza A virus (IAV). Further, IAV interacts with STING through its conserved hemagglutinin fusion peptide (FP). Interestingly, FP antagonizes interferon production induced by membrane fusion or IAV but not by cGAMP or DNA. Similar to the enveloped RNA viruses, membrane fusion stimulates interferon production in a STING-dependent but cGAS-independent manner. Abolishment of this pathway led to reduced interferon production and impaired control of enveloped RNA viruses. Thus, enveloped RNA viruses stimulate a cGAS-independent STING pathway, which is targeted by IAV. PMID:26893169

  20. Influenza A virus targets a cGAS-independent STING pathway that controls enveloped RNA viruses.

    PubMed

    Holm, Christian K; Rahbek, Stine H; Gad, Hans Henrik; Bak, Rasmus O; Jakobsen, Martin R; Jiang, Zhaozaho; Hansen, Anne Louise; Jensen, Simon K; Sun, Chenglong; Thomsen, Martin K; Laustsen, Anders; Nielsen, Camilla G; Severinsen, Kasper; Xiong, Yingluo; Burdette, Dara L; Hornung, Veit; Lebbink, Robert Jan; Duch, Mogens; Fitzgerald, Katherine A; Bahrami, Shervin; Mikkelsen, Jakob Giehm; Hartmann, Rune; Paludan, Søren R

    2016-02-19

    Stimulator of interferon genes (STING) is known be involved in control of DNA viruses but has an unexplored role in control of RNA viruses. During infection with DNA viruses STING is activated downstream of cGAMP synthase (cGAS) to induce type I interferon. Here we identify a STING-dependent, cGAS-independent pathway important for full interferon production and antiviral control of enveloped RNA viruses, including influenza A virus (IAV). Further, IAV interacts with STING through its conserved hemagglutinin fusion peptide (FP). Interestingly, FP antagonizes interferon production induced by membrane fusion or IAV but not by cGAMP or DNA. Similar to the enveloped RNA viruses, membrane fusion stimulates interferon production in a STING-dependent but cGAS-independent manner. Abolishment of this pathway led to reduced interferon production and impaired control of enveloped RNA viruses. Thus, enveloped RNA viruses stimulate a cGAS-independent STING pathway, which is targeted by IAV.

  1. Shikonin protects dopaminergic cell line PC12 against 6-hydroxydopamine-mediated neurotoxicity via both glutathione-dependent and independent pathways and by inhibiting apoptosis.

    PubMed

    Esmaeilzadeh, Emran; Gardaneh, Mossa; Gharib, Ehsan; Sabouni, Farzaneh

    2013-08-01

    We have investigated the mechanism of shikonin function on protection of dopaminergic neurons against 6-OHDA-induced neurotoxicity. Treatment of rat pheochromocytoma cell line PC12 by serial dilutions of shikonin determined 10 μM of the compound as its optimum concentration for protection saving nearly 70 % of the cells against toxicity. Reverse transcription-PCR analysis of shikonin-treated cells showed threefold increase in mRNA levels of glutathione peroxidase-1 (GPX-1) as a representative component of the intracellular anti-oxidant defense system. To elucidate shikonin-GPX1 relationships and maximize protection, we transduced PC12 cells using recombinant lentivirus vectors that harbored GPX-1 coding sequence. This change upregulated GPX-1 expression, increased peroxidase activity and made neuronal cells resistant to 6-OHDA-mediated toxicity. More importantly, addition of shikonin to GPX1-overexpressing PC12 cells augmented GPX-1 protein content by eightfold leading to fivefold increase of enzymatic activity, 91 % cell survival against neurotoxicity and concomitant increases in intracellular glutathione (GSH) levels. Depletion of intracellular GSH rendered all cell groups highly susceptible to toxicity; however, shikonin was capable of partially saving them. Subsequently, GSH-independent superoxide dismutase mRNA was found upregulated by shikonin. As signs of apoptosis inhibition, the compound upregulated Bcl-2, downregulated Bax, and prevented cell nuclei from undergoing morphological changes typical of apoptosis. Also, a co-staining method demonstrated GPX-1 overexpression significantly increases the percent of live cells that is maximized by shikonin treatment. Our data indicate that shikonin as an antioxidant compound protects dopaminergic neurons against 6-OHDA toxicity and enhances their survival via both glutathione-dependent and direct anti-apoptotic pathways.

  2. Rosiglitazone elevates sensitization of drug-resistant oral epidermoid carcinoma cells to vincristine by G2/M-phase arrest, independent of PPAR-γ pathway.

    PubMed

    Wang, Hong-Yuan; Zhang, Ying; Zhou, Yue; Lu, Yu-Yin; Wang, Wen-Fang; Xin, Ming; Guo, Xiu-Li

    2016-10-01

    Rosiglitazone (ROSI), an oral antidiabetic agent, has been reported the anti-cancer properties recent years. In this paper, the potency of ROSI as a synergistic drug for vincristine (VCR) on resistant oral cancer cells was investigated. We found that ROSI potently enhanced the susceptibility of KB cells or KB/V cells to VCR in a dose manner and the synergy in KB/V cells was much more prominent than that in KB cells. The synergistic anti-proliferative effect of ROSI and VCR was associated with inhibition on tubulin polymerization, cell cycle arrest in G2/M phase and cell apoptosis induction, but has no effect on drug efflux-protein P-gp and was independent with PPARγ. The combination treatment of ROSI and VCR could regulate the PTEN/PI3K/AKT survival pathway with an upregulation of PTEN and down-regulation of p-AKT. The effect of G2/M phase arrest was associated with the upregulation of cyclin B1 and downregulation of p-cdc2. The apoptosis induction of ROSI and VCR was partly due to an upregulation of cleaved PARP and downregulation of Bcl-2/Bax ratio. In addition, combination treatment of ROSI and VCR had also shown anti-angiogenic effect by suppressing the migration and blocking the capillary tube formation of HUVECs. More importantly, this combination treatment induced an acceptably weak cytotoxicity in human normal HL-7702 cells, GES-1 cells and HUVECs. Taken together, ROSI may be used as a potential compound for combinatorial therapy or as a complement to VCR for treatment on oral cancer, especially on that have acquired resistance to VCR therapy.

  3. hnRNP L binds to CA repeats in the 3'UTR of bcl-2 mRNA

    SciTech Connect

    Lee, Dong-Hyoung; Lim, Mi-Hyun; Youn, Dong-Ye; Jung, Seung Eun; Ahn, Young Soo; Tsujimoto, Yoshihide; Lee, Jeong-Hwa

    2009-05-08

    We previously reported that the CA-repeat sequence in the 3'-untranslated region (3'UTR) of bcl-2 mRNA is involved in the decay of bcl-2 mRNA. However, the trans-acting factor for the CA element in bcl-2 mRNA remains unidentified. The heterogeneous nuclear ribonucleoprotein L (hnRNP L), an intron splicing factor, has been reported to bind to CA repeats and CA clusters in the 3'UTR of several genes. We reported herein that the CA repeats of bcl-2 mRNA have the potential to form a distinct ribonuclear protein complex in cytoplasmic extracts of MCF-7 cells, as evidenced by RNA electrophoretic mobility shift assays (REMSA). A super-shift assay using the hnRNP L antibody completely shifted the complex. Immunoprecipitation with the hnRNP L antibody and MCF-7 cells followed by RT-PCR revealed that hnRNP L interacts with endogenous bcl-2 mRNA in vivo. Furthermore, the suppression of hnRNP L in MCF-7 cells by the transfection of siRNA for hnRNP L resulted in a delay in the degradation of RNA transcripts including CA repeats of bcl-2 mRNA in vitro, suggesting that the interaction between hnRNPL and CA repeats of bcl-2 mRNA participates in destabilizing bcl-2 mRNA.

  4. Bcl-2 protects against FCCP-induced apoptosis and mitochondrial membrane potential depolarization in PC12 cells.

    PubMed

    Dispersyn, G; Nuydens, R; Connors, R; Borgers, M; Geerts, H

    1999-08-05

    This report addresses the relation between Bcl-2 and mitochondrial membrane potential (DeltaPsi(m)) in apoptotic cell death. Rat pheochromocytoma (PC12) cells are differentiated into neuron-like cells with nerve growth factor (NGF). It is known that Bcl-2 can attenuate apoptosis induced by deprivation of neurotrophic factor. The protective effect of Bcl-2 has been correlated with preservation of DeltaPsi(m). Protonophores, such as carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP), collapse the proton gradient across the mitochondrial inner membrane, resulting in a complete abolition of the mitochondrial membrane potential. Based on the analysis of morphology, of phosphatidylserine exposure and of nuclear fragmentation we conclude that FCCP induces apoptosis in PC12 cells, which can be prevented by overexpression of Bcl-2. To determine whether the cytoprotective effect of Bcl-2 is due to stabilization of DeltaPsi(m), we investigated the effect of Bcl-2 on changes in DeltaPsi(m), induced by FCCP in PC12 cells. We showed that treatment with FCCP induced a reduction in DeltaPsi(m), as assessed with the lipophilic cationic membrane potential-sensitive dye JC-1, and that Bcl-2 protects against FCCP-induced changes in NGF differentiated PC12 cells. Our data indicate that Bcl-2 protects against FCCP-induced cell death by stabilizing DeltaPsi(m).

  5. Bcl-2 overexpression does not promote axonal regeneration of the entorhino-hippocampal connections in vitro after axotomy.

    PubMed

    Solé, Marta; Fontana, Xavier; Gavín, Rosalina; Soriano, Eduardo; del Río, José Antonio

    2004-09-10

    CNS lesions trigger cell death in injured neurons and glia. Genes of the bcl-2 family play crucial roles in the control of apoptosis and cell survival in the CNS. Recently, it has been suggested that overexpression of bcl-2 induces axonal elongation and regeneration in vitro and in vivo. Here, we analyze the regenerative potential of bcl-2 overexpression in the axotomized entorhino-hippocampal connection in organotypic slice cocultures. Our results show that in slice cocultures from bcl-2-overexpressing mice, there is a decrease in the number of dead neurons in the entorhinal cortex. In addition, axonal regeneration is not enhanced after axotomy. Thus, in the entorhino-hippocampal formation in vitro, bcl-2 overexpression rescues neurons from axotomy-induced cell death but fails to enhance the regeneration of the entorhino-hippocampal connection.

  6. Age- and area-dependent distinct effects of ethanol on Bax and Bcl-2 expression in prenatal rat brain.

    PubMed

    Lee, Hae Young; Naha, Nibedita; Kim, Jong Hun; Jo, Mi Ja; Min, Kwan Sik; Seong, Hwan Hoo; Shin, Dong Hoon; Kim, Myeong Ok

    2008-09-01

    Cell proliferation and differentiation are critical processes in a developing fetal rat brain, during which programmed cell death (PCD) also plays an important role. One of the decisive factors for PCD is Bcl-2 family proteins, where Bax induces cell death, whereas Bcl-2 acts as an inhibitor of PCD. As maternal drinking is known to cause fetal alcohol syndrome (FAS) or malformation of the fetal brain during pregnancy, the objective of the present study was to investigate whether maternal ethanol exposure alters the PCD-related Bax and Bcl-2 protein expression during fetal brain development. Pregnant female rats were orally treated with 10% ethanol and the subsequent expressions of the Bax and Bcl-2 proteins examined in the fetal brain, including the forebrain, midbrain, and hindbrain, from gestational day (GD) 15.5 to GD 19.5, using Western blots, in situ hybridization, and immunohistochemistry. With regard to the ratio of Bcl-2 to Bax proteins (Bcl-2/Bax), the Bax protein was dominant in the forebrain and midbrain of the control GD 15.5 fetuses, except for the hindbrain, when compared with the respective ethanol-treated groups. Moreover, Bcl-2 became dominant in the midbrain of the control GD 17.5 fetuses when compared with the ethanoltreated group, representing an alternation of the natural PCD process by ethanol. Furthermore, a differential expression of the Bcl-2 and Bax proteins was found in the differentiating and migrating zones of the cortex, hippocampus, thalamus, and cerebellum. Thus, when taken together, the present results suggest that ethanol affects PCD in the cell differentiation and migration zones of the prenatal rat brain by modulating Bax and Bcl-2 expression in an age- and area-dependent manner. Therefore, this is the first evidence that ethanol may alter FAS-associated embryonic brain development through the alteration of Bax and Bcl-2 expression.

  7. AMBRA1, a Novel BH3-Like Protein: New Insights Into the AMBRA1-BCL2-Family Proteins Relationship.

    PubMed

    Di Rita, A; Strappazzon, F

    2017-01-01

    Cellular homeostasis swings like a pendulum backward and forward between life and death. Two of the main processes, which regulate this equilibrium, are autophagy and apoptosis. While autophagy is a highly conserved self-digestion mechanism that mediates degradation of damaged or surplus components, apoptosis is a programmed cell suicide in which typical death signals induce the elimination of undesired cells. Both these processes are highly regulated by complex molecular machineries, including some common proteins whose "dual role" favors one process or the other. Among these proteins, the well-known antiapoptotic factor BCL2 downregulates autophagy through interactions with the essential autophagic effectors, BECN1/BECLIN 1 and AMBRA1. Recently, we have demonstrated that the proautophagic protein AMBRA1 contains a BH3 domain necessary for AMBRA1 binding with the antiapoptotic factor BCL2. We found that the AMBRA1-BCL2 couple have a "dual role" in autophagy and apoptosis: the mitochondrial pool of BCL2 is able to inhibit AMBRA1-dependent autophagy, whereas in cell death conditions, the cleaved form of AMBRA1 (AMBRA1(CT)), resulting from CASP/CASPASES-cleavage, abrogates the prosurvival activity of BCL2 and promotes a proapoptotic amplification loop. The CASP-cleaved form of AMBRA1 bound other antiapoptotic members of the BCL2 family proteins such as MCL1 and BCL2L1/BCL-X; by contrast, no binding could be detected with the proapoptotic-BCL2 factors such as BAK1/BAK and BAX. These findings underline an intricate interplay between autophagy and cell death in which the proautophagic protein AMBRA1 and the antiapoptotic BCL2 family members are the major players. Here, we give an overview of the AMBRA1-BCL2 family proteins interactome and its involvement in controlling life and cell death. We discuss a putative therapeutic target which offers the novel BH3 motif identified in the C-terminal part of AMBRA1.

  8. Lantana camara Induces Apoptosis by Bcl-2 Family and Caspases Activation.

    PubMed

    Han, Eun Byeol; Chang, Bo Yoon; Jung, Young Suk; Kim, Sung Yeon

    2015-04-01

    Breast cancer is one of the most common cancers worldwide, and the second most fatal cancer in women after lung cancer. Because there are instances of cancer resistance to existing therapies, studies focused on the identification of novel therapeutic drugs are very important. In this study, we identified a natural anticancer agent from Lantana camara, a flowering plant species of the genus Verbena. The extract obtained from the L. camara exhibited cell death properties in the human breast cancer cell line, MCF-7. We found that the apoptosis induced by treatment with the L. camara extract was regulated by the Bcl-2 family. Bid and Bax was increased and Bcl-2 was decreased by L. camara extract. L. camara extract modulated cleavage of caspase-8, and caspase-9, as well as poly (ADP-ribose) polymerase (PARP). Our results support the potential use of the L. camara extract as an anti-breast cancer drug.

  9. Down-regulation of Bcl-2 in rat substantia nigra after focal cerebral ischemia.

    PubMed

    Arango-Dávila, Cesar A; Cardona-Gomez, Gloria P; Gallego-Gomez, Juan C; Garcia-Segura, Luis M; Pimienta, Hernán J

    2004-06-28

    After occlusion of the middle cerebral artery in rats, a robust neuronal loss occurs in the ipsilateral substantia nigra reticulata. In this study we have assessed whether degeneration of the substantia nigra is accompanied by changes in the expression of the anti-apoptotic protein Bcl-2. Neuronal loss was assessed by neuronal nuclei (NeuN) immunoreactivity. A significant decrease of Bcl-2 expression was observed in the substantia nigra 12, 24 and 72 h after middle cerebral artery occlusion. These results suggest that the secondary neuronal loss in the substantia nigra could be related with the modification of proteins regulating programmed cell death. Exo-focal cell death may explain the appearance of neuropsychiatric symptoms that are not correlated with the primary site of lesion.

  10. Multimodal interaction with BCL-2 family proteins underlies the proapoptotic activity of PUMA BH3.

    PubMed

    Edwards, Amanda L; Gavathiotis, Evripidis; LaBelle, James L; Braun, Craig R; Opoku-Nsiah, Kwadwo A; Bird, Gregory H; Walensky, Loren D

    2013-07-25

    PUMA is a proapoptotic BCL-2 family member that drives the apoptotic response to a diversity of cellular insults. Deciphering the spectrum of PUMA interactions that confer its context-dependent proapoptotic properties remains a high priority goal. Here, we report the synthesis of PUMA SAHBs, structurally stabilized PUMA BH3 helices that, in addition to broadly targeting antiapoptotic proteins, directly bind to proapoptotic BAX. NMR, photocrosslinking, and biochemical analyses revealed that PUMA SAHBs engage an α1/α6 trigger site on BAX to initiate its functional activation. We further demonstrated that a cell-permeable PUMA SAHB analog induces apoptosis in neuroblastoma cells and, like expressed PUMA protein, engages BCL-2, MCL-1, and BAX. Thus, we find that PUMA BH3 is a dual antiapoptotic inhibitor and proapoptotic direct activator, and its mimetics may serve as effective pharmacologic triggers of apoptosis in resistant human cancers.

  11. A balanced translocation disrupting BCL2L10 and PNLDC1 segregates with affective psychosis

    PubMed Central

    Bouwkamp, Christian G.; Kievit, Anneke J. A.; Olgiati, Simone; Breedveld, Guido J.; Coesmans, Michiel; Bonifati, Vincenzo

    2016-01-01

    Affective psychoses are a group of severe psychiatric disorders, including schizoaffective disorder and bipolar I disorder, together affecting ∼1% of the population. Despite their high heritability, the molecular genetics and neurobiology of affective psychosis remain largely elusive. Here, we describe the identification of a structural genetic variant segregating with affective psychosis in a family with multiple members suffering from bipolar I disorder or schizoaffective disorder, bipolar type. A balanced translocation involving chromosomes 6 and 15 was detected by karyotyping and fluorescence in‐situ hybridization (FISH). Using whole‐genome sequencing, we rapidly delineated the translocation breakpoints as corresponding intragenic events disrupting BCL2L10 and PNLDC1. These data warrant further consideration for BCL2L10 and PNLDC1 as novel candidates for affective psychosis. © 2016 The Authors. American Journal of Medical Genetics Part B: Neuropsychiatric Genetics Published by Wiley Periodicals, Inc. PMID:27260655

  12. An ATM-independent S-phase checkpoint response involves CHK1 pathway

    NASA Technical Reports Server (NTRS)

    Zhou, Xiang-Yang; Wang, Xiang; Hu, Baocheng; Guan, Jun; Iliakis, George; Wang, Ya

    2002-01-01

    After exposure to genotoxic stress, proliferating cells actively slow down the DNA replication through a S-phase checkpoint to provide time for repair. We report that in addition to the ataxia-telangiectasia mutated (ATM)-dependent pathway that controls the fast response, there is an ATM-independent pathway that controls the slow response to regulate the S-phase checkpoint after ionizing radiation in mammalian cells. The slow response of S-phase checkpoint, which is resistant to wortmannin, sensitive to caffeine and UCN-01, and related to cyclin-dependent kinase phosphorylation, is much stronger in CHK1 overexpressed cells, and it could be abolished by Chk1 antisense oligonucleotides. These results provide evidence that the ATM-independent slow response of S-phase checkpoint involves CHK1 pathway.

  13. PORCN moonlights in a Wnt-independent pathway that regulates cancer cell proliferation.

    PubMed

    Covey, Tracy M; Kaur, Simran; Tan Ong, Tina; Proffitt, Kyle D; Wu, Yonghui; Tan, Patrick; Virshup, David M

    2012-01-01

    Porcupine (PORCN) is a membrane-bound O-acyl transferase that is required for the palmitoylation of Wnt proteins, and that is essential in diverse Wnt pathways for Wnt-Wntless (WLS) binding, Wnt secretion, and Wnt signaling activity. We tested if PORCN was required for the proliferation of transformed cells. Knockdown of PORCN by multiple independent siRNAs results in a cell growth defect in a subset of epithelial cancer cell lines. The growth defect is transformation-dependent in human mammary epithelial (HMEC) cells. Additionally, inducible PORCN knockdown by two independent shRNAs markedly reduces the growth of established MDA-MB-231 cancers in orthotopic xenografts in immunodeficient mice. Unexpectedly, the proliferation defect resulting from loss of PORCN occurs in a Wnt-independent manner, as it is rescued by re-expression of catalytically inactive PORCN, and is not seen after RNAi-mediated knockdown of the Wnt carrier protein WLS, nor after treatment with the PORCN inhibitor IWP. Consistent with a role in a Wnt-independent pathway, knockdown of PORCN regulates a distinct set of genes that are not altered by other inhibitors of Wnt signaling. PORCN protein thus appears to moonlight in a novel signaling pathway that is rate-limiting for cancer cell growth and tumorigenesis independent of its enzymatic function in Wnt biosynthesis and secretion.

  14. Prometaphase arrest-dependent phosphorylation of Bcl-2 and Bim reduces the association of Bcl-2 with Bak or Bim, provoking Bak activation and mitochondrial apoptosis in nocodazole-treated Jurkat T cells.

    PubMed

    Han, Cho Rong; Jun, Do Youn; Lee, Ji Young; Kim, Young Ho

    2014-01-01

    Treatment of Jurkat T cells with the microtubule-depolymerizing agent nocodazole (NOC) caused prometaphase arrest and apoptosis. NOC-induced mitochondrial apoptotic events including Bak activation, Δψm loss, cytochrome c release, and caspase cascade activation were blocked by Bcl-2 overexpression. However, mitotic arrest, Cdc25C activation, upregulation of cyclin B1 levels, Cdk1 activation, Bcl-2 phosphorylation at Thr-56 and Ser-70, and Bim phosphorylation were retained. The treatment of Jurkat T cells concomitantly with NOC and the G1/S-blocking agent hydroxyurea resulted in G1/S arrest and complete abrogation of all apoptotic events. The association of Bcl-2 with Bim or Bak declined after the prometaphase arrest-dependent phosphorylation of Bcl-2 and Bim, whereas the association of Bcl-2 with Bax remained relatively constant. Although Bax was redistributed from the cytosol to the mitochondria, resulting in an increase in the mitochondrial level of Bax following NOC treatment, the subcellular localization of Bcl-2, Bim, Bak and apoptosis-inducing factor was confined to the mitochondrial fraction irrespective of NOC treatment. Experiments using selective caspase inhibitors showed that mitochondria-dependent activation of caspase-9 and -3 was crucial for NOC-induced apoptosis. NOC-induced phosphorylation of Bcl-2 and Bim, Δψm loss, and mitochondria-dependent apoptotic events were significantly suppressed by a Cdk1 inhibitor roscovitine, but not by the JNK inhibitor SP600125 or the p38 MAPK inhibitor SB203580. These results show that the prometaphase arrest-dependent phosphorylation of Bcl-2 and Bim, which was mediated by Cdk1, could reduce the association of Bcl-2 with Bak or Bim to allow Bak activation and mitochondrial apoptotic events in Jurkat T cells exposed to NOC.

  15. MiR-16 modulate temozolomide resistance by regulating BCL-2 in human glioma cells.

    PubMed

    Han, Jing; Chen, Qianxue

    2015-01-01

    Temozolomide (TMZ) with radiotherapy is the current standard of care for newly diagnosed glioma. However, glioma patients who are treated with the drug often develop resistance to it and some other drugs. Recently studies have shown that microRNAs (miRNAs) play an important role in drug resistance. In present study, we first examined the sensitivity to temozolomide in six glioma cell lines, and established a resistant variant, U251MG/TR cells from TMZ-sensitive glioma cell line, U251MG. We then performed a comprehensive analysis of miRNA expressions in U251MG/TR and parental cells using cancer microRNA PCR Array. Among the downregulated microRNAs was miR-16, members of miR-15/16 family, whose expression was further validated by qRT-PCR in U251MG/TR and U251MG cells. The selective microRNA, miR-16 mimics or inhibitor was respectively transfected into U251MG/TR cells and AM38 cell. We found that treatment with the mimics of miR-16 greatly decreased the sensitivity of U251MG/TR cells to temozolomide, while sensitivity to these drugs was increased by treatment with the miR-16 inhibitor. In addition, the downregulation of miR-16 in temozolomide-sensitive AM38 cells was concurrent with the upregulation of Bcl-2 protein. Conversely, overexpression of miR-16 in temozolomide-resistant cells inhibited Bcl-2 expression and decreased temozolomide resistance. In conclusion, MiR-16 mediated temozolomide-resistance in glioma cells by modulation of apoptosis via targeting Bcl-2, which suggesting that miR-16 and Bcl-2 would be potential therapeutic targets for glioma therapy.

  16. Regulation of Calcium Fluxes and Apoptosis by BCL-2 Family Proteins in Prostate Cancer Cells

    DTIC Science & Technology

    2007-02-01

    The biochemistry of apoptosis . Nature 2000;407(6805):770-6. 4. Gross A, McDonnell JM, Korsmeyer SJ. BCL-2 family members and the mitochondria in...25. Nakagawa T, Zhu H, Morishima N, et al. Caspase-12 mediates endoplasmic-reticulum- specific apoptosis and cytotoxicity by amyloid-beta. Nature ...AD_________________ Award Number: W81XWH–04-1-0182 TITLE: Regulation of calcium fluxes and apoptosis

  17. Effect of curcumin on Bcl-2 and Bax expression in nude mice prostate cancer

    PubMed Central

    Yang, Jiayi; Ning, Jianping; Peng, Linlin; He, Dan

    2015-01-01

    Prostate cancer is a common malignant tumor in urinary system. Curcumin has curative effect on many kinds of cancers and can inhibit prostate cancer (PC)-3 cells proliferation. This study aimed to explore the curcumin induced prostate cancer cell apoptosis and apoptosis related proteins Bcl-2 and Bax expression. PC-3 cells were injected subcutaneously to the nude mice to establish the tumor model. The nude mice were randomly divided into group C (normal saline), group B (6% polyethylene glycol and 6% anhydrous ethanol), group H, M, L (100 mg/kg, 50 mg/kg, and 25 mg/kg curcumin). The tumor volume was measured every 6 days to draw the tumor growth curve. The mice were killed at the 30th day after injection to weight the tumor. TUNEL assay was applied to determine cell apoptosis. Immunohistochemistry was used to detect Bcl-2 and Bax expression. The tumor volume and weight in group H, M, L were significantly lower than the control group (C, B) (P<0.05), and the inhibitory rate increased following the curcumin dose increase. Compared with the control group, Bcl-2 expression in group H, M, L gradually decreased, while Bax protein expression increased (P<0.05). The cell apoptosis rate showed no statistical difference between group B and C, while it increased in curcumin group H, M, and L (P<0.05). Curcumin could inhibit PC-3 growth, decrease tumor volume, reduce tumor weight, and induce cell apoptosis under the skin of nude mice by up-regulating Bax and down-regulating Bcl-2. PMID:26464676

  18. Effect of curcumin on Bcl-2 and Bax expression in nude mice prostate cancer.

    PubMed

    Yang, Jiayi; Ning, Jianping; Peng, Linlin; He, Dan

    2015-01-01

    Prostate cancer is a common malignant tumor in urinary system. Curcumin has curative effect on many kinds of cancers and can inhibit prostate cancer (PC)-3 cells proliferation. This study aimed to explore the curcumin induced prostate cancer cell apoptosis and apoptosis related proteins Bcl-2 and Bax expression. PC-3 cells were injected subcutaneously to the nude mice to establish the tumor model. The nude mice were randomly divided into group C (normal saline), group B (6% polyethylene glycol and 6% anhydrous ethanol), group H, M, L (100 mg/kg, 50 mg/kg, and 25 mg/kg curcumin). The tumor volume was measured every 6 days to draw the tumor growth curve. The mice were killed at the 30(th) day after injection to weight the tumor. TUNEL assay was applied to determine cell apoptosis. Immunohistochemistry was used to detect Bcl-2 and Bax expression. The tumor volume and weight in group H, M, L were significantly lower than the control group (C, B) (P<0.05), and the inhibitory rate increased following the curcumin dose increase. Compared with the control group, Bcl-2 expression in group H, M, L gradually decreased, while Bax protein expression increased (P<0.05). The cell apoptosis rate showed no statistical difference between group B and C, while it increased in curcumin group H, M, and L (P<0.05). Curcumin could inhibit PC-3 growth, decrease tumor volume, reduce tumor weight, and induce cell apoptosis under the skin of nude mice by up-regulating Bax and down-regulating Bcl-2.

  19. Axotomized neonatal motoneurons overexpressing the bcl2 proto-oncogene retain functional electrophysiological properties.

    PubMed Central

    Alberi, S; Raggenbass, M; de Bilbao, F; Dubois-Dauphin, M

    1996-01-01

    Bcl2 overexpression prevents axotomy-induced neuronal death of neonatal facial motoneurons, as defined by morphological criteria. However, the functional properties of these surviving lesioned transgenic neurons are unknown. Using transgenic mice overexpressing the protein Bcl2, we have investigated the bioelectrical properties of transgenic facial motoneurons from 7 to 20 days after neonatal unilateral axotomy using brain-stem slices and whole cell patch-clamp recording. Nonaxotomized facial motoneurons from wild-type and transgenic mice had similar properties; they had an input resistance of 38 +/- 6 M omega and fired repetitively after injection of positive current pulses. When cells were voltage-clamped at or near their resting membrane potential, alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), N-methyl-D-aspartic acid (NMDA), or vasopressin generated sustained inward currents. In transgenic axotomized mice, facial motoneurons could be found located ipsilaterally to the lesion; they had an input resistance of 150 +/- 30 M omega, indicating that they were smaller in size, fired repetitively, and were also responsive to AMPA, NMDA, and vasopressin. Morphological measurements achieved 1 week after the lesion have shown that application of brain-derived neurotrophic factor prevented the reduction in size of axotomized transgenic motoneurons. These data indicate that Bcl2 not only prevents morphological apoptotic death of axotomized neonatal transgenic motoneurons but also permits motoneurons to conserve functional electrophysiological properties. Images Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 PMID:8633001

  20. Germinal center reentries of BCL2-overexpressing B cells drive follicular lymphoma progression

    PubMed Central

    Sungalee, Stéphanie; Mamessier, Emilie; Morgado, Ester; Grégoire, Emilie; Brohawn, Philip Z.; Morehouse, Christopher A.; Jouve, Nathalie; Monvoisin, Céline; Menard, Cédric; Debroas, Guilhaume; Faroudi, Mustapha; Mechin, Violaine; Navarro, Jean-Marc; Drevet, Charlotte; Eberle, Franziska C.; Chasson, Lionel; Baudimont, Fannie; Mancini, Stéphane J.; Tellier, Julie; Picquenot, Jean-Michel; Kelly, Rachel; Vineis, Paolo; Ruminy, Philippe; Chetaille, Bruno; Jaffe, Elaine S.; Schiff, Claudine; Hardwigsen, Jean; Tice, David A.; Higgs, Brandon W.; Tarte, Karin; Nadel, Bertrand; Roulland, Sandrine

    2014-01-01

    It has recently been demonstrated that memory B cells can reenter and reengage germinal center (GC) reactions, opening the possibility that multi-hit lymphomagenesis gradually occurs throughout life during successive immunological challenges. Here, we investigated this scenario in follicular lymphoma (FL), an indolent GC-derived malignancy. We developed a mouse model that recapitulates the FL hallmark t(14;18) translocation, which results in constitutive activation of antiapoptotic protein B cell lymphoma 2 (BCL2) in a subset of B cells, and applied a combination of molecular and immunofluorescence approaches to track normal and t(14;18)+ memory B cells in human and BCL2-overexpressing B cells in murine lymphoid tissues. BCL2-overexpressing B cells required multiple GC transits before acquiring FL-associated developmental arrest and presenting as GC B cells with constitutive activation–induced cytidine deaminase (AID) mutator activity. Moreover, multiple reentries into the GC were necessary for the progression to advanced precursor stages of FL. Together, our results demonstrate that protracted subversion of immune dynamics contributes to early dissemination and progression of t(14;18)+ precursors and shapes the systemic presentation of FL patients. PMID:25384217

  1. Dexamethasone treatment promotes Bcl-2 dependence in multiple myeloma resulting in sensitivity to venetoclax.

    PubMed

    Matulis, S M; Gupta, V A; Nooka, A K; Hollen, H V; Kaufman, J L; Lonial, S; Boise, L H

    2016-05-01

    Venetoclax (ABT-199), a specific inhibitor of the anti-apoptotic protein Bcl-2, is currently in phase I clinical trials for multiple myeloma. The results suggest that venetoclax is only active in a small cohort of patients therefore we wanted to determine its efficacy when used in combination. Combining venetoclax with melphalan or carfilzomib produced additive or better cell death in four of the five cell lines tested. The most striking results were seen with dexamethasone (Dex). Co-treatment of human myeloma cell lines and primary patient samples, with Dex and venetoclax, significantly increased cell death over venetoclax alone in four of the five cell lines, and in all patient samples tested. The mechanism by which this occurs is an increase in the expression of both Bcl-2 and Bim upon addition of Dex. This results in alterations in Bim binding to anti-apoptotic proteins. Dex shifts Bim binding towards Bcl-2 resulting in increased sensitivity to venetoclax. These data suggest that knowledge of drug-induced alterations of Bim-binding patterns may help inform better combination drug regimens. Furthermore, the data indicate combining this novel therapeutic with Dex could be an effective therapy for a broader range of patients than would be predicted by single-agent activity.

  2. Bcl-2/MDM2 Dual Inhibitors Based on Universal Pyramid-Like α-Helical Mimetics.

    PubMed

    Wang, Ziqian; Song, Ting; Feng, Yingang; Guo, Zongwei; Fan, Yudan; Xu, Wenjie; Liu, Lu; Wang, Anhui; Zhang, Zhichao

    2016-04-14

    No α-helical mimetic that exhibits Bcl-2/MDM2 dual inhibition has been rationally designed due to the different helicities of the α-helixes at their binding interfaces. Herein, we extracted a one-turn α-helix-mimicking ortho-triarene unit from o-phenylene foldamers. Linking benzamide substrates with a rotatable C-N bond, we constructed a novel semirigid pyramid-like scaffold that could support its two-turn α-helix mimicry without aromatic stacking interactions and could adopt the different dihedral angles of the key residues of p53 and BH3-only peptides. On the basis of this universal scaffold, a series of substituent groups were installed to capture the key residues of both p53TAD and BimBH3 and balance the differences of the bulks between them. Identified by FP, ITC, and NMR spectroscopy, a compound 6e (zq-1) that directly binds to Mcl-1, Bcl-2, and MDM2 with balanced submicromolar affinities was obtained. Cell-based experiments demonstrated its antitumor ability through Bcl-2/MDM2 dual inhibition simultaneously.

  3. Xanthorrhizol induced DNA fragmentation in HepG2 cells involving Bcl-2 family proteins

    SciTech Connect

    Tee, Thiam-Tsui; Cheah, Yew-Hoong; Meenakshii, Nallappan; Mohd Sharom, Mohd Yusof; Azimahtol Hawariah, Lope Pihie

    2012-04-20

    Highlights: Black-Right-Pointing-Pointer We isolated xanthorrhizol, a sesquiterpenoid compound from Curcuma xanthorrhiza. Black-Right-Pointing-Pointer Xanthorrhizol induced apoptosis in HepG2 cells as observed using SEM. Black-Right-Pointing-Pointer Apoptosis in xanthorrhizol-treated HepG2 cells involved Bcl-2 family proteins. Black-Right-Pointing-Pointer DNA fragmentation was observed in xanthorrhizol-treated HepG2 cells. Black-Right-Pointing-Pointer DNA fragmentation maybe due to cleavage of PARP and DFF45/ICAD proteins. -- Abstract: Xanthorrhizol is a plant-derived pharmacologically active sesquiterpenoid compound isolated from Curcuma xanthorrhiza. Previously, we have reported that xanthorrhizol inhibited the proliferation of HepG2 human hepatoma cells by inducing apoptotic cell death via caspase activation. Here, we attempt to further elucidate the mode of action of xanthorrhizol. Apoptosis in xanthorrhizol-treated HepG2 cells as observed by scanning electron microscopy was accompanied by truncation of BID; reduction of both anti-apoptotic Bcl-2 and Bcl-X{sub L} expression; cleavage of PARP and DFF45/ICAD proteins and DNA fragmentation. Taken together, these results suggest xanthorrhizol as a potent antiproliferative agent on HepG2 cells by inducing apoptosis via Bcl-2 family members. Hence we proposed that xanthorrhizol could be used as an anti-liver cancer drug for future studies.

  4. Chlorpromazine inhibits mitochondrial apoptotic pathway via increasing expression of tissue factor.

    PubMed

    Wu, Jing; Li, Aimei; Li, Yujun; Li, Xiaoguang; Zhang, Qingmeng; Song, Wuqi; Wang, Yao; Ogutu, James O; Wang, Jindong; Li, Jianbo; Tang, Renkuan; Zhang, Fengmin

    2016-01-01

    Chlorpromazine (CPZ) is a widely used antipsychotic drug with antagonistic effect on dopamine receptors. Accumulating evidence has shown that CPZ plays a neuroprotective role in various models of toxicity and apoptosis. However, the underlying mechanism contributing to this protective effect remains unclear. Here, we evaluate the effect of CPZ on mitochondrial apoptotic pathway in the neuron system. Higher levels of B-cell lymphoma-2 (Bcl-2) and tissue factor (TF) but lower apoptotic rate were found in hippocampus of CPZ-treated schizophrenic patients compared with non-antipsychotic treated controls. Additionally, both short-term and long-term treatment of CPZ in rats could up-regulate the levels of Bcl-2 and TF with no cytotoxic effects. In the in vitro experiment, expression of Bcl-2 was up-regulated in the C6 glioma cells transfected with pEGFP-N1-TF recombinant plasmid. Furthermore, in another independent rat model of apoptosis, compared with the group administrated with alcohol only, the brains of the CPZ-pretreated rats showed lower expression of cleaved caspase-3, cytochrome c and Bax, but higher expression of Bcl-2 and TF. Our data demonstrate that CPZ exerts its neuronal protective effects through inhibiting the activation of mitochondrial apoptotic pathway by up-regulating TF expression, thus providing new insight into CPZ function and application.

  5. The B-cell lymphoma 2 (BCL2)-inhibitors, ABT-737 and ABT-263, are substrates for P-glycoprotein

    SciTech Connect

    Vogler, Meike; Dickens, David; Dyer, Martin J.S.; Owen, Andrew; Pirmohamed, Munir; Cohen, Gerald M.

    2011-05-06

    Highlights: {yields} The BCL2-inhibitor ABT-263 is a substrate for P-glycoprotein. {yields} Apoptosis is inhibited by P-glycoprotein expression. {yields} Overexpression of P-glycoprotein may contribute to resistance to ABT-263 or ABT-737. -- Abstract: Inhibition of BCL2 proteins is one of the most promising new approaches to targeted cancer therapy resulting in the induction of apoptosis. Amongst the most specific BCL2-inhibitors identified are ABT-737 and ABT-263. However, targeted therapy is often only effective for a limited amount of time because of the occurrence of drug resistance. In this study, the interaction of BCL2-inhibitors with the drug efflux transporter P-glycoprotein was investigated. Using {sup 3}H labelled ABT-263, we found that cells with high P-glycoprotein activity accumulated less drug. In addition, cells with increased P-glycoprotein expression were more resistant to apoptosis induced by either ABT-737 or ABT-263. Addition of tariquidar or verapamil sensitized the cells to BCL2-inhibitor treatment, resulting in higher apoptosis. Our data suggest that the BCL2-inhibitors ABT-737 and ABT-263 are substrates for P-glycoprotein. Over-expression of P-glycoprotein may be, at least partly, responsible for resistance to these BCL2-inhibitors.

  6. Heartwood extract of Acacia catechu induces apoptosis in human breast carcinoma by altering bax/bcl-2 ratio

    PubMed Central

    Ghate, Nikhil Baban; Hazra, Bibhabasu; Sarkar, Rhitajit; Mandal, Nripendranath

    2014-01-01

    Background: The heartwood extract of A. catechu, called pale catechu or “Katha” in Hindi has been widely used in traditional Indian medicinal system. Although various pharmacological properties of this plant had been reported previously, only a few were concerned with the anticancer activity of this plant. Objective: The objective was to assess the in vitro anticancer and apoptosis inducing effect of 70% methanolic extract of “Katha” (ACME) on human breast adenocarcinoma cell line (MCF-7). Materials and Methods: MCF-7 cell line was treated with increasing concentrations of ACME and cell viability was calculated. Flow cytometric methods were used to confirm the apoptosis promoting role of ACME. Morphological changes were then analysed using confocal microscopy. Western blotting was then performed to investigate the expression of apoptogenic proteins and to analyse the activation of caspases. Results: ACME showed significant cytotoxicity to MCF-7 cells with an IC50 value of 288.85 ± 25.79 μg/ml. Flow cytometric analysis and morphological studies confirmed that ACME is able to induce apoptosis in MCF-7 cells. Furthermore, immunoblot results suggested the pathway of apoptosis induction by increasing Bax/Bcl-2 ratio which results in the activation of caspase-cascade and ultimately leads to the cleavage of Poly adeno ribose polymerase (PARP). Conclusion: These results provide the evidence that ACME is able to inhibit the proliferation of MCF-7 cells by inducing apoptosis through intrinsic pathway. PMID:24695415

  7. Maintenance of the HIV reservoir is antagonized by selective BCL2 inhibition.

    PubMed

    Cummins, Nathan W; Sainski-Nguyen, Amy M; Natesampillai, Sekar; Aboulnasr, Fatma; Kaufmann, Scott; Badley, Andrew D

    2017-03-22

    Decay of the HIV reservoir is slowed over time in part by expansion of the pool of HIV infected cells. This expansion reflects homeostatic proliferation of infected cells by IL-7 or antigenic stimulation, as well as new rounds of infection of susceptible target cells. As novel therapies are being developed to accelerate the decay of the latent HIV reservoir, it will be important to identify interventions that prevent expansion and/or repopulation of the latent HIV reservoir. Our previous studies showed that HIV protease cleaves the host protein procaspase 8 to generate Casp8p41, which can bind and activate BAK to induce apoptosis of infected cells. In circumstances where expression of the anti-apoptotic protein BCL2 is high, Casp8p41 instead binds BCL2, and cell death does not occur. This effect can be overcome by treating cells with the clinically approved BCL2 antagonist venetoclax, which prevents Casp8p41 from binding BCL2, thereby allowing Casp8p41 to bind BAK and kill the infected cell. Herein we assess whether the events that maintain the HIV reservoir are also antagonized by venetoclax. Using the J-Lat 10.6 model of persistent infection, we demonstrate that proliferation and HIV expression is countered by venetoclax, which causes preferential killing of the HIV expressing cells. Similarly, during new rounds of infection of primary CD4 T cells, venetoclax causes selective killing of HIV infected cells, resulting in decreased number of HIV DNA containing cells.IMPORTANCE Cure of HIV infection requires an intervention that reduces HIV reservoir size. A variety of approaches are being tested for their ability to impact HIV reservoir size. Even if successful, however, these approaches will need to be combined with additional complementary approaches that prevent replenishment or repopulation of the HIV reservoir. Our previous studies have shown that the FDA approved BCL2 antagonist venetoclax has a beneficial effect on the HIV reservoir size following HIV

  8. Identification of a calcineurin-independent pathway required for sodium ion stress response in Saccharomyces cerevisiae.

    PubMed Central

    Ganster, R W; McCartney, R R; Schmidt, M C

    1998-01-01

    The calcium-dependent protein phosphatase calcineurin plays an essential role in ion homeostasis in yeast. In this study, we identify a parallel ion stress response pathway that is independent of the calcineurin signaling pathway. Cells with null alleles in both STD1 and its homologue, MTH1, manifest numerous phenotypes observed in calcineurin mutants, including sodium, lithium, manganese, and hydroxyl ion sensitivity, as well as alpha factor toxicity. Furthermore, increased gene dosage of STD1 suppresses the ion stress phenotypes in calcineurin mutants and confers halotolerance in wild-type cells. However, Std1p functions in a calcineurin-independent ion stress response pathway, since a std1 mth1 mutant is FK506 sensitive under conditions of ion stress. Mutations in other genes known to regulate gene expression in response to changes in glucose concentration, including SNF3, RGT2, and SNF5, also affect cell growth under ion stress conditions. Gene expression studies indicate that the regulation of HAL1 and PMR2 expression is affected by STD1 gene dosage. Taken together, our data demonstrate that response to ion stress requires the participation of both calcineurin-dependent and -independent pathways. PMID:9725828

  9. Prognostic impact of history of follicular lymphoma, induction regimen and stem cell transplant in patients with MYC/BCL2 double hit lymphoma

    PubMed Central

    Li, Shaoying; Saksena, Annapurna; Desai, Parth; Xu, Jie; Zuo, Zhuang; Lin, Pei; Tang, Guilin; Yin, C. Cameron; Seegmiller, Adam; Jorgensen, Jeffrey L.; Miranda, Roberto N.; Reddy, Nishitha M; Bueso-Ramos, Carlos; Medeiros, L. Jeffrey

    2016-01-01

    MYC/BCL2 double hit lymphoma (DHL) has been the subject of many studies; however, no study has systemically compared the clinicopathologic features and prognostic factors between patients with de novo disease versus those with a history of follicular lymphoma (FL). In addition, the prognostic importance of several other issues remains controversial in these patients. In this retrospective study, we assess 157 patients with MYC/BCL2 DHL including 108 patients with de novo disease and 49 patients with a history of FL or rarely other types of low-grade B-cell lymphoma. Patients received induction chemotherapy regimens including 61 R-CHOP, 31 R-EPOCH, 29 R-Hyper-CVAD, and 23 other regimens. Thirty-nine patients received a stem cell transplant (SCT) including 31 autologous and 8 allogeneic. Sixty-two patients achieved complete remission (CR) after induction chemotherapy. Median overall survival (OS) was 19 months. Clinicopathologic features were similar between patients with de novo tumors versus those with a history of FL (P > 0.05). Using multivariate analysis, achieving CR, undergoing SCT, stage and the International Prognostic Index were independent prognostic factors for OS. Stem cell transplantion was associated with improved OS in patients who failed to achieve CR, but not in patients who achieved CR after induction chemotherapy. In conclusion, patients with MYC/BCL2 DHL who present with de novo disease and patients with a history of FL have a similarly poor prognosis. Achievement of CR, regardless of the induction chemotherapy regimen used, is the most important independent prognostic factor. Patients who do not achieve CR after induction chemotherapy may benefit from SCT. PMID:27203548

  10. Identification of the Essential Role of Viral Bcl-2 for Kaposi's Sarcoma-Associated Herpesvirus Lytic Replication

    PubMed Central

    Liang, Qiming; Chang, Brian; Lee, Patrick; Brulois, Kevin F.; Ge, Jianning; Shi, Mude; Rodgers, Mary A.; Feng, Pinghui; Oh, Byung-Ha; Liang, Chengyu

    2015-01-01

    ABSTRACT Kaposi's sarcoma-associated herpesvirus (KSHV) evades host defenses through tight suppression of autophagy by targeting each step of its signal transduction: by viral Bcl-2 (vBcl-2) in vesicle nucleation, by viral FLIP (vFLIP) in vesicle elongation, and by K7 in vesicle maturation. By exploring the roles of KSHV autophagy-modulating genes, we found, surprisingly, that vBcl-2 is essential for KSHV lytic replication, whereas vFLIP and K7 are dispensable. Knocking out vBcl-2 from the KSHV genome resulted in decreased lytic gene expression at the mRNA and protein levels, a lower viral DNA copy number, and, consequently, a dramatic reduction in the amount of progeny infectious viruses, as also described in the accompanying article (A. Gelgor, I. Kalt, S. Bergson, K. F. Brulois, J. U. Jung, and R. Sarid, J Virol 89:5298–5307, 2015). More importantly, the antiapoptotic and antiautophagic functions of vBcl-2 were not required for KSHV lytic replication. Using a comprehensive mutagenesis analysis, we identified that glutamic acid 14 (E14) of vBcl-2 is critical for KSHV lytic replication. Mutating E14 to alanine totally blocked KSHV lytic replication but showed little or no effect on the antiapoptotic and antiautophagic functions of vBcl-2. Our study indicates that vBcl-2 harbors at least three important and genetically separable functions to modulate both cellular signaling and the virus life cycle. IMPORTANCE The present study shows for the first time that vBcl-2 is essential for KSHV lytic replication. Removal of the vBcl-2 gene results in a lower level of KSHV lytic gene expression, impaired viral DNA replication, and consequently, a dramatic reduction in the level of progeny production. More importantly, the role of vBcl-2 in KSHV lytic replication is genetically separated from its antiapoptotic and antiautophagic functions, suggesting that the KSHV Bcl-2 carries a novel function in viral lytic replication. PMID:25740994

  11. A179L, a viral Bcl-2 homologue, targets the core Bcl-2 apoptotic machinery and its upstream BH3 activators with selective binding restrictions for Bid and Noxa

    PubMed Central

    Galindo, Inmaculada; Hernaez, Bruno; Díaz-Gil, Gema; Escribano, Jose M.; Alonso, Covadonga

    2008-01-01

    Several large DNA viruses encode Bcl-2 protein homologues involved in the regulation of the cellular apoptosis cascade. This regulation often involves the interaction of these viral proteins with diverse cellular Bcl-2 family members. We have identified the specific interactions of A179L, an African swine fever virus (ASFV) Bcl-2 homologue, with the active forms of the porcine BH3-only Bid protein (truncated Bid p13 and p15). Transient expression of ASFV A179L gene in Vero cells prevented apoptosis induced by these active forms of Bid protein. Interestingly, A179L protein was able to interact, also with the main core Bcl-2 proapoptotic proteins Bax and Bak, and with several BH3-only proteins with selective binding restrictions for full length Bid and Noxa. These results suggest a fine regulation for A179L action in the suppression of apoptosis in infected cells which is essential for efficient virus replication. PMID:18329683

  12. Inhibitory heterotrimeric GTP-binding proteins inhibit hydrogen peroxide-induced apoptosis by up-regulation of Bcl-2 via NF-{kappa}B in H1299 human lung cancer cells

    SciTech Connect

    Seo, Mi Ran; Nam, Hyo-Jung; Kim, So-Young; Juhnn, Yong-Sung

    2009-04-03

    Inhibitory heterotrimeric GTP-binding proteins (Gi proteins) mediate a variety of signaling pathways by coupling receptors and effectors to regulate cellular proliferation, differentiation, and apoptosis. However, the role of Gi proteins in the modulation of hydrogen peroxide-induced apoptosis is not clearly understood. Thus, we investigated the effect of Gi proteins on hydrogen peroxide-induced apoptosis and the underlying mechanisms in H1299 human lung cancer cells. The stable expression of constitutively active alpha subunits of Gi1 (G{alpha}i1QL), Gi2, or Gi3 inhibited hydrogen peroxide-induced apoptosis. The expression of G{alpha}i1QL up-regulated Bcl-2 expression, and the knockdown of Bcl-2 with siRNA abolished the anti-apoptotic effect of G{alpha}i1QL. G{alpha}i1 induced the transcription of Bcl-2 by activation of NF-{kappa}B, which resulted from an increase in NF-{kappa}B p50 protein. We conclude that G{alpha}i1 inhibits hydrogen peroxide-induced apoptosis of H1299 lung cancer cells by up-regulating the transcription of Bcl-2 through a p50-mediated NF-{kappa}B activation.

  13. Phenazine-1-carboxamide (PCN) from Pseudomonas sp. strain PUP6 selectively induced apoptosis in lung (A549) and breast (MDA MB-231) cancer cells by inhibition of antiapoptotic Bcl-2 family proteins.

    PubMed

    Kennedy, R Kamaraj; Veena, V; Naik, P Ravindra; Lakshmi, Pragna; Krishna, R; Sudharani, S; Sakthivel, N

    2015-06-01

    Phenazine-1-carboxamide (PCN), a naturally occurring simple phenazine derivative isolated from Pseudomonas sp. strain PUP6, exhibited selective cytotoxic activity against lung (A549) and breast (MDA-MB-231) cancer cell lines in differential and dose-dependent manner compared to normal peripheral blood mononuclear cells. PCN-treated cancer cells showed the induction of apoptosis as evidenced by the release of low level of LDH, morphological characteristics, production of reactive oxygen species, loss of mitochondrial membrane potential (ΔΨm) and induction of caspase-3. At molecular level, PCN instigates apoptosis by mitochondrial intrinsic apoptotic pathway via the overexpression of p53, Bax, cytochrome C release and activation of caspase-3 with the inhibition of oncogenic anti-apoptotic proteins such as PARP and Bcl-2 family proteins (Bcl-2, Bcl-w and Bcl-xL). The in silico docking studies of PCN targeted against the anti-apoptotic members of Bcl-2 family proteins revealed the interaction of PCN with the BH3 domain, which might lead to the induction of apoptosis due to the inhibition of antiapoptotic proteins. Due to its innate inhibition potential of antiapoptotic Bcl-2 family proteins, PCN may be used as potent anticancer agent against both lung and breast cancer.

  14. Inhibitory heterotrimeric GTP-binding proteins inhibit hydrogen peroxide-induced apoptosis by up-regulation of Bcl-2 via NF-kappaB in H1299 human lung cancer cells.

    PubMed

    Seo, Miran; Nam, Hyo-Jung; Kim, So-Young; Juhnn, Yong-Sung

    2009-04-03

    Inhibitory heterotrimeric GTP-binding proteins (Gi proteins) mediate a variety of signaling pathways by coupling receptors and effectors to regulate cellular proliferation, differentiation, and apoptosis. However, the role of Gi proteins in the modulation of hydrogen peroxide-induced apoptosis is not clearly understood. Thus, we investigated the effect of Gi proteins on hydrogen peroxide-induced apoptosis and the underlying mechanisms in H1299 human lung cancer cells. The stable expression of constitutively active alpha subunits of Gi1 (Galphai1QL), Gi2, or Gi3 inhibited hydrogen peroxide-induced apoptosis. The expression of Galphai1QL up-regulated Bcl-2 expression, and the knockdown of Bcl-2 with siRNA abolished the anti-apoptotic effect of Galphai1QL. Galphai1 induced the transcription of Bcl-2 by activation of NF-kappaB, which resulted from an increase in NF-kappaB p50 protein. We conclude that Galphai1 inhibits hydrogen peroxide-induced apoptosis of H1299 lung cancer cells by up-regulating the transcription of Bcl-2 through a p50-mediated NF-kappaB activation.

  15. Quercetin induces protective autophagy and apoptosis through ER stress via the p-STAT3/Bcl-2 axis in ovarian cancer.

    PubMed

    Liu, Y; Gong, W; Yang, Z Y; Zhou, X S; Gong, C; Zhang, T R; Wei, X; Ma, D; Ye, F; Gao, Q L

    2017-04-01

    Quercetin (3,3',4',5,7-pentahydroxyflavone, Qu) is a promising cancer chemo-preventive agent for various cancers because it inhibits disease progression and promotes apoptotic cell death. In our previous study, we demonstrated that Qu could evoke ER stress to enhance drug cytotoxicity in ovarian cancer (OC). However, Qu-induced ER stress in OC is still poorly understood. Here, we demonstrated that Qu evoked ER stress to involve in mitochondria apoptosis pathway via the p-STAT3/Bcl-2 axis in OC cell lines and in primary OC cells. Unexpectedly, inhibition of ER stress did not reverse Qu-induced cell death. Further functional studies revealed that Qu-induced ER stress could activate protective autophagy concomitantly by activating the p-STAT3/Bcl-2 axis in this process. Moreover, the autophagy scavenger 3-MA was shown to enhance Qu's anticancer effects in an ovarian cancer mice xenograft model. These findings revealed a novel role of ER stress as a "double edge sword" participating in Qu-induced apoptosis of OC and might provide a new angle to consider in clinical studies of biological modifiers that may circumvent drug resistance in patients by targeting protective autophagy pathways.

  16. Genetic variants in the apoptosis gene BCL2L1 improve response to interferon-based treatment of hepatitis C virus genotype 3 infection.

    PubMed

    Clausen, Louise Nygaard; Weis, Nina; Ladelund, Steen; Madsen, Lone; Lunding, Suzanne; Tarp, Britta; Christensen, Peer Brehm; Krarup, Henrik Bygum; Møller, Axel; Gerstoft, Jan; Clausen, Mette Rye; Benfield, Thomas

    2015-02-02

    Genetic variation upstream of the apoptosis pathway has been associated with outcome of hepatitis C virus (HCV) infection. We investigated genetic polymorphisms in the intrinsic apoptosis pathway to assess their influence on sustained virological response (SVR) to pegylated interferon-α and ribavirin (pegIFN/RBV) treatment of HCV genotypes 1 and 3 infections. We conducted a candidate gene association study in a prospective cohort of 201 chronic HCV-infected individuals undergoing treatment with pegIFN/RBV. Differences between groups were compared in logistic regression adjusted for age, HCV viral load and interleukin 28B genotypes. Four single nucleotide polymorphisms (SNPs) located in the B-cell lymphoma 2-like 1 (BCL2L1) gene were significantly associated with SVR. SVR rates were significantly higher for carriers of the beneficial rs1484994 CC genotypes. In multivariate logistic regression, the rs1484994 SNP combined CC+TC genotypes were associated with a 3.4 higher odds ratio (OR) in SVR for the HCV genotype 3 (p=0.02). The effect estimate was similar for genotype 1, but the association did not reach statistical significance. In conclusion, anti-apoptotic SNPs in the BCL2L1 gene were predictive of SVR to pegIFN/RBV treatment in HCV genotypes 1 and 3 infected individuals. These SNPs may be used in prediction of SVR, but further studies are needed.

  17. Role of CSL-dependent and independent Notch signaling pathways in cell apoptosis.

    PubMed

    Zeng, Chong; Xing, Rui; Liu, Jing; Xing, Feiyue

    2016-01-01

    Apoptosis is a normally biological phenomenon in various organisms, involving complexly molecular mechanisms with a series of signaling processes. Notch signaling is found evolutionarily conserved in many species, playing a critical role in embryonic development, normal tissue homeostasis, angiogenesis and immunoregulation. The focus of this review is on currently novel advances about roles of CSL-dependent and independent Notch signaling pathways in cell apoptosis. The CSL can bind Notch intracellular domain (NIC) to act as a switch in mediating transcriptional activation or inactivation of the Notch signaling pathway downstream genes in the nucleus. It shows that CSL-dependent signaling regulates the cell apoptosis through Hes-1-PTEN-AKT-mTOR signaling, but rather the CSL-independent signaling mediates the cell apoptosis possibly via NIC-mTORC2-AKT-mTOR signaling, providing a new insight into apoptotic mechanisms.

  18. Phenylalanine ammonia lyase catalyzed synthesis of amino acids by an MIO-cofactor independent pathway.

    PubMed

    Lovelock, Sarah L; Lloyd, Richard C; Turner, Nicholas J

    2014-04-25

    Phenylalanine ammonia lyases (PALs) belong to a family of 4-methylideneimidazole-5-one (MIO) cofactor dependent enzymes which are responsible for the conversion of L-phenylalanine into trans-cinnamic acid in eukaryotic and prokaryotic organisms. Under conditions of high ammonia concentration, this deamination reaction is reversible and hence there is considerable interest in the development of PALs as biocatalysts for the enantioselective synthesis of non-natural amino acids. Herein the discovery of a previously unobserved competing MIO-independent reaction pathway, which proceeds in a non-stereoselective manner and results in the generation of both L- and D-phenylalanine derivatives, is described. The mechanism of the MIO-independent pathway is explored through isotopic-labeling studies and mutagenesis of key active-site residues. The results obtained are consistent with amino acid deamination occurring by a stepwise E1 cB elimination mechanism.

  19. Distinct routes to metastasis: plasticity-dependent and plasticity-independent pathways

    PubMed Central

    Somarelli, J A; Schaeffer, D; Marengo, M S; Bepler, T; Rouse, D; Ware, K E; Hish, A J; Zhao, Y; Buckley, A F; Epstein, J I; Armstrong, A J; Virshup, D M; Garcia-Blanco, M A

    2016-01-01

    The cascade that culminates in macrometastases is thought to be mediated by phenotypic plasticity, including epithelial–mesenchymal and mesenchymal–epithelial transitions (EMT and MET). Although there is substantial support for the role of EMT in driving cancer cell invasion and dissemination, much less is known about the importance of MET in the later steps of metastatic colonization. We created novel reporters, which integrate transcriptional and post-transcriptional regulation, to test whether MET is required for metastasis in multiple in vivo cancer models. In a model of carcinosarcoma, metastasis occurred via an MET-dependent pathway; however, in two prostate carcinoma models, metastatic colonization was MET independent. Our results provide evidence for both MET-dependent and MET-independent metastatic pathways. PMID:26751776

  20. Human memory B cells originate from three distinct germinal center-dependent and -independent maturation pathways.

    PubMed

    Berkowska, Magdalena A; Driessen, Gertjan J A; Bikos, Vasilis; Grosserichter-Wagener, Christina; Stamatopoulos, Kostas; Cerutti, Andrea; He, Bing; Biermann, Katharina; Lange, Johan F; van der Burg, Mirjam; van Dongen, Jacques J M; van Zelm, Menno C

    2011-08-25

    Multiple distinct memory B-cell subsets have been identified in humans, but it remains unclear how their phenotypic diversity corresponds to the type of responses from which they originate. Especially, the contribution of germinal center-independent responses in humans remains controversial. We defined 6 memory B-cell subsets based on their antigen-experienced phenotype and differential expression of CD27 and IgH isotypes. Molecular characterization of their replication history, Ig somatic hypermutation, and class-switch profiles demonstrated their origin from 3 different pathways. CD27⁻IgG⁺ and CD27⁺IgM⁺ B cells are derived from primary germinal center reactions, and CD27⁺IgA⁺ and CD27⁺IgG⁺ B cells are from consecutive germinal center responses (pathway 1). In contrast, natural effector and CD27⁻IgA⁺ memory B cells have limited proliferation and are also present in CD40L-deficient patients, reflecting a germinal center-independent origin. Natural effector cells at least in part originate from systemic responses in the splenic marginal zone (pathway 2). CD27⁻IgA⁺ cells share low replication history and dominant Igλ and IgA2 use with gut lamina propria IgA+ B cells, suggesting their common origin from local germinal center-independent responses (pathway 3). Our findings shed light on human germinal center-dependent and -independent B-cell memory formation and provide new opportunities to study these processes in immunologic diseases.

  1. Drug-induced destabilization of bcl-2 mRNA: a new approach for inducing apoptosis in tumor cells.

    PubMed

    Otake, Yoko; Sengupta, Tapas K; Bandyopadhyay, Sumita; Spicer, Eleanor K; Fernandes, Daniel J

    2004-06-01

    Recent evidence suggests that the 3' untranslated region (3' UTR) of some mRNAs is a molecular hotspot for pathology. The 3' UTR of bcl-2 mRNA contains several AU-rich elements (AREs) that promote mRNA destabilization. Recent studies have demonstrated that the protein, nucleolin, binds to an ARE in bcl-2 mRNA, thereby protecting this mRNA from nuclease degradation. All-trans retinoic acid, taxol and okadiac acid induce downregulation or inactivation of nucleolin, which destabilizes bcl-2 mRNA and triggers apoptosis. The ARE instability elements in bcl-2 mRNA are potential therapeutic targets for inducing apoptosis and overcoming drug resistance in cancer cells.

  2. Isolated Follicles Enriched for Centroblasts and Lacking t(14;18)/BCL2 in Lymphoid Tissue: Diagnostic and Clinical Implications

    PubMed Central

    Gratzinger, Dita; Jones, Carol D.; Zehnder, James L.; Bangs, Charles D.; Cherry, Athena; Warnke, Roger A.; Natkunam, Yasodha

    2016-01-01

    We sought to address the significance of isolated follicles that exhibit atypical morphologic features that may be mistaken for lymphoma in a background of reactive lymphoid tissue. Seven cases that demonstrated centroblast-predominant isolated follicles and absent BCL2 staining in otherwise-normal lymph nodes were studied. Four of seven cases showed clonal B-cell proliferations amid a polyclonal B cell background; all cases lacked the IGH-BCL2 translocation and BCL2 protein expression. Although three patients had invasive breast carcinoma at other sites, none were associated with systemic lymphoma up to 44 months after diagnosis. The immunoarchitectural features of these highly unusual cases raise the question of whether a predominance of centroblasts and/or absence of BCL2 expression could represent a precursor lesion or atypical reactive phenomenon. Differentiating such cases from follicular lymphoma or another mimic is critical, lest patients with indolent proliferations be exposed to unnecessarily aggressive treatment. PMID:26991267

  3. TR4 orphan nuclear receptor functions as an apoptosis modulator via regulation of Bcl-2 gene expression

    SciTech Connect

    Kim, Eungseok; Ma, Wen-Lung; Lin, Din-Lii; Inui, Shigeki; Chen, Yuh-Ling; Chang, Chawnshang . E-mail: chang@urmc.rochester.edu

    2007-09-21

    While Bcl-2 plays an important role in cell apoptosis, its relationship to the orphan nuclear receptors remains unclear. Here we report that mouse embryonic fibroblast (MEF) cells prepared from TR4-deficient (TR4{sup -} {sup /-}) mice are more susceptible to UV-irradiation mediated apoptosis compared to TR4-Wildtype (TR4 {sup +/+}) littermates. Substantial increasing TR4{sup -} {sup /-} MEF apoptosis to UV-irradiation was correlated to the down-regulation of Bcl-2 RNA and protein expression and collaterally increased caspase-3 activity. Furthermore, this TR4-induced Bcl-2 gene expression can be suppressed by co-transfection with TR4 coregulators, such as androgen receptor (AR) and receptor-interacting protein 140 (RIP140) in a dose-dependent manner. Together, our results demonstrate that TR4 might function as an apoptosis modulator through induction of Bcl-2 gene expression.

  4. Key Survival Factor, Mcl-1, Correlates with Sensitivity to Combined Bcl-2/Bcl-xL Blockade.

    PubMed

    Williams, Michelle M; Lee, Linus; Hicks, Donna J; Joly, Meghan M; Elion, David; Rahman, Bushra; McKernan, Courtney; Sanchez, Violeta; Balko, Justin M; Stricker, Thomas; Estrada, Monica Valeria; Cook, Rebecca S

    2017-03-01

    An estimated 40,000 deaths will be attributed to breast cancer in 2016, underscoring the need for improved therapies. Evading cell death is a major hallmark of cancer, driving tumor progression and therapeutic resistance. To evade apoptosis, cancers use antiapoptotic Bcl-2 proteins to bind to and neutralize apoptotic activators, such as Bim. Investigation of antiapoptotic Bcl-2 family members in clinical breast cancer datasets revealed greater expression and more frequent gene amplification of MCL1 as compared with BCL2 or BCL2L1 (Bcl-xL) across three major molecular breast cancer subtypes, Luminal (A and B), HER2-enriched, and Basal-like. While Mcl-1 protein expression was elevated in estrogen receptor α (ERα)-positive and ERα-negative tumors as compared with normal breast, Mcl-1 staining was higher in ERα(+) tumors. Targeted Mcl-1 blockade using RNAi increased caspase-mediated cell death in ERα(+) breast cancer cells, resulting in sustained growth inhibition. In contrast, combined blockade of Bcl-2 and Bcl-xL only transiently induced apoptosis, as cells rapidly acclimated through Mcl-1 upregulation and enhanced Mcl-1 activity, as measured in situ using Mcl-1/Bim proximity ligation assays. Importantly, MCL1 gene expression levels correlated inversely with sensitivity to pharmacologic Bcl-2/Bcl-xL inhibition in luminal breast cancer cells, whereas no relationship was seen between the gene expression of BCL2 or BCL2L1 and sensitivity to Bcl-2/Bcl-xL inhibition. These results demonstrate that breast cancers rapidly deploy Mcl-1 to promote cell survival, particularly when challenged with blockade of other Bcl-2 family members, warranting the continued development of Mcl-1-selective inhibitors for targeted tumor cell killing.Implications: Mcl-1 levels predict breast cancer response to inhibitors targeting other Bcl-2 family members, and demonstrate the key role played by Mcl-1 in resistance to this drug class. Mol Cancer Res; 15(3); 259-68. ©2016 AACR.

  5. Research fellowship programs as a pathway for training independent clinical pharmacy scientists.

    PubMed

    Mueller, Eric W; Bishop, Jeffrey R; Kanaan, Abir O; Kiser, Tyree H; Phan, Hanna; Yang, Katherine Y

    2015-03-01

    The American College of Clinical Pharmacy (ACCP) Research Affairs Committee published a commentary in 2013 on training clinical pharmacy scientists in the context of changes in economic, professional, political, and research environments. The commentary centered on the opportunities for pharmacists in clinical/translational research including strategies for ACCP, colleges of pharmacy, and the profession to increase the number and impact of clinical pharmacy scientists. A postdoctoral fellowship is cited as a current training pathway, capable of producing independent and productive pharmacy researchers. However, a decline in the number of programs, decreased funding availability, and variability in fellowship program activities and research focus have brought into question the relevance of this research training pathway to meet demand and opportunities. In response to these points, this commentary examines the state of research fellowship training including the current ACCP research fellowship review process, the need for standardization of research fellowship programs, and strategies to strengthen and promote research fellowships as relevant researcher training pathways.

  6. Asymmetrically dividing Drosophila neuroblasts utilize two spatially and temporally independent cytokinesis pathways

    PubMed Central

    Roth, Michaela; Roubinet, Chantal; Iffländer, Niklas; Ferrand, Alexia; Cabernard, Clemens

    2015-01-01

    Precise cleavage furrow positioning is required for faithful chromosome segregation and cell fate determinant distribution. In most metazoan cells, contractile ring placement is regulated by the mitotic spindle through the centralspindlin complex, and potentially also the chromosomal passenger complex (CPC). Drosophila neuroblasts, asymmetrically dividing neural stem cells, but also other cells utilize both spindle-dependent and spindle-independent cleavage furrow positioning pathways. However, the relative contribution of each pathway towards cytokinesis is currently unclear. Here we report that in Drosophila neuroblasts, the mitotic spindle, but not polarity cues, controls the localization of the CPC component Survivin. We also show that Survivin and the mitotic spindle are required to stabilize the position of the cleavage furrow in late anaphase and to complete furrow constriction. These results support the model that two spatially and temporally separate pathways control different key aspects during asymmetric cell division, ensuring correct cell fate determinant segregation and neuroblast self-renewal. PMID:25791062

  7. Serum starvation and thymidine double blocking achieved efficient cell cycle synchronization and altered the expression of p27, p53, bcl-2 in canine breast cancer cells.

    PubMed

    Tong, Jinjin; Sun, Dongdong; Yang, Chao; Wang, Yingxue; Sun, Sichao; Li, Qing; Bao, Jun; Liu, Yun

    2016-04-01

    Cell synchronization is an approach to obtain cell populations of the same stage, which is a prerequisite to studying the regulation of cell cycle progression in vivo. Serum starvation and thymidine double blocking (TdR) are two important practices in studying cell cycle synchronization. However, their effects on canine cancer cells as well as the regulatory mechanisms by these two methods are poorly understood. In this study, we determined the optimum conditions of serum starvation and TdR and their effects on cell cycle synchronization. We further explored the involvement of PI3K/Akt signaling pathway in the cell cycle synchronization by investigating the expression of three key genes (p27, p53 and bcl-2). Serum starvation resulted in a reversible cell cycle arrest and synchronously progress through G0/G1. The highest percentage of CHMm cells (87.47%) in G0/G1 stage was obtained after 42 h incubation with 0.5% fetal bovine serum (FBS). TdR double blocking could arrest 98.9% of CHMm cells in G1/S phase (0 h of release), and could arrest 93.74% of CHMm cells in S phase after 4h of release. We also found that the p27, p53, bcl-2 genes were most highly expressed in G0/G1 phase. Our current work revealed that serum starvation and TdR methods could achieve sufficient synchronization of CHMm cells. Moreover, the expression of p27, p53 and bcl-2 genes was related to cyclical movements and apoptosis. Our results will provide a new insight into cell cycle regulation and reprogramming of canine cancer cells induced by serum starvation and TdR blocking.

  8. Blockage of Glyoxalase I Inhibits Colorectal Tumorigenesis and Tumor Growth via Upregulation of STAT1, p53, and Bax and Downregulation of c-Myc and Bcl-2

    PubMed Central

    Chen, Yuan; Fang, Lei; Zhang, Jiali; Li, Gefei; Ma, Mengni; Li, Changxi; Lyu, Jianxin; Meng, Qing H.

    2017-01-01

    GlyoxalaseI (GLOI) is an enzyme that catalyzes methylglyoxal metabolism. Overexpression of GLOI has been documented in numerous tumor tissues, including colorectal cancer (CRC). The antitumor effects of GLOI depletion have been demonstrated in some types of cancer, but its role in CRC and the mechanisms underlying this activity remain largely unknown. Our purpose was to investigate the antitumor effects of depleted GLOI on CRC in vitro and in vivo. RNA interference was used to deplete GLOI activity in four CRC cell lines. The cells’ proliferation, apoptosis, migration, and invasion were assessed by using the Cell Counting Kit-8, plate colony formation assay, flow cytometry, and transwell assays. Protein and mRNA levels were analyzed by western blot and quantitative real-time PCR (qRT-PCR), respectively. The antitumor effect of GLOI depletion in vivo was investigated in a SW620 xenograft tumor model in BALB/c nude mice. Our results show that GLOI is over-expressed in the CRC cell lines. GLOI depletion inhibited the proliferation, colony formation, migration, and invasion and induced apoptosis of all CRC cells compared with the controls. The levels of signal transducer and activator of transcription 1 (STAT1), p53, and Bcl-2 assaciated X protein (Bax) were upregulated by GLOI depletion, while cellular homologue of avian myelocytomatosis virus oncogene (c-Myc) and B cell lymphoma/lewkmia-2 (Bcl-2) were downregulated. Moreover, the growth of SW620-induced CRC tumors in BALB/c nude mice was significantly attenuated by GLOI depletion. The expression levels of STAT1, p53, and Bax were increased and those of c-Myc and Bcl-2 were decreased in the GLOI-depleted tumors. Our findings demonstrate that GLOI depletion has an antitumor effect through the STAT1 or p53 signaling pathways in CRC, suggesting that GLOI is a potential therapeutic target. PMID:28282916

  9. Association of Bax Expression and Bcl2/Bax Ratio with Clinical and Molecular Prognostic Markers in Chronic Lymphocytic Leukemia

    PubMed Central

    Vucicevic, Ksenija; Jakovljevic, Vladimir; Colovic, Natasa; Tosic, Natasa; Kostic, Tatjana; Glumac, Irena; Pavlovic, Sonja; Colovic, Milica

    2016-01-01

    Summary Background In chronic lymphocytic leukemia (CLL), in vivo apoptotic resistance of malignant B lymphocytes results, in part, from the intrinsic defects of their apoptotic machinery. These include genetic alterations and aberrant expression of many apoptosis regulators, among which the Bcl2 family members play a central role. Aim The aim of this study was to investigate the association of pro-apoptotic Bax gene expression and Bcl2/Bax ratio with the clinical features of CLL patients as well as with molecular prognostic markers, namely the mutational status of rearranged immunoglobulin heavy variable (IGHV) genes and lipoprotein lipase (LPL) gene expression. Methods We analyzed the expression of Bax mRNA and Bcl2/Bax mRNA ratio in the peripheral blood mononuclear cells of 58 unselected CLL patients and 10 healthy controls by the quantitative reverse-transcriptase polymerase chain reaction. Results We detected significant Bax gene overexpression in CLL samples compared to non-leukemic samples (p=0.003), as well as an elevated Bcl2/Bax ratio (p=<0.001). Regarding the association with prognostic markers, the Bcl2/Bax ratio showed a negative correlation to lymphocyte doubling time (r=-0.307; p=0.0451), while high-level Bax expression was associated with LPL-positive status (p=0.035). Both the expression of Bax and Bcl2/Bax ratio were higher in patients with unmutated vs. mutated IGHV rearrangements, but this difference did not reach statistical significance. Conclusions Our results suggest that dysregulated expression of Bcl2 and Bax, which leads to a high Bcl2/Bax ratio in leukemic cells, contributes to the pathogenesis and clinical course of CLL. PMID:28356875

  10. Mercury Methylation Independent of the Acetyl-Coenzyme A Pathway in Sulfate-Reducing Bacteria

    PubMed Central

    Ekstrom, Eileen B.; Morel, François M. M.; Benoit, Janina M.

    2003-01-01

    Sulfate-reducing bacteria (SRB) in anoxic waters and sediments are the major producers of methylmercury in aquatic systems. Although a considerable amount of work has addressed the environmental factors that control methylmercury formation and the conditions that control bioavailability of inorganic mercury to SRB, little work has been undertaken analyzing the biochemical mechanism of methylmercury production. The acetyl-coenzyme A (CoA) pathway has been implicated as being key to mercury methylation in one SRB strain, Desulfovibrio desulfuricans LS, but this result has not been extended to other SRB species. To probe whether the acetyl-CoA pathway is the controlling biochemical process for methylmercury production in SRB, five incomplete-oxidizing SRB strains and two Desulfobacter strains that do not use the acetyl-CoA pathway for major carbon metabolism were assayed for methylmercury formation and acetyl-CoA pathway enzyme activities. Three of the SRB strains were also incubated with chloroform to inhibit the acetyl-CoA pathway. So far, all species that have been found to have acetyl-CoA activity are complete oxidizers that require the acetyl-CoA pathway for basic metabolism, as well as methylate mercury. Chloroform inhibits Hg methylation in these species either by blocking the methylating enzyme or by indirect effects on metabolism and growth. However, we have identified four incomplete-oxidizing strains that clearly do not utilize the acetyl-CoA pathway either for metabolism or mercury methylation (as confirmed by the absence of chloroform inhibition). Hg methylation is thus independent of the acetyl-CoA pathway and may not require vitamin B12 in some and perhaps many incomplete-oxidizing SRB strains. PMID:12957930

  11. MRP- and BCL-2-mediated drug resistance in human SCLC: effects of apoptotic sphingolipids in vitro.

    PubMed

    Khodadadian, M; Leroux, M E; Auzenne, E; Ghosh, S C; Farquhar, D; Evans, R; Spohn, W; Zou, Y; Klostergaard, J

    2009-10-01

    Multidrug-resistance-associated protein (MRP) and BCL-2 contribute to drug resistance expressed in SCLC. To establish whether MRP-mediated drug resistance affects sphingolipid (SL)-induced apoptosis in SCLC, we first examined the human SCLC cell line, UMCC-1, and its MRP over-expressing, drug-resistant subline, UMCC-1/VP. Despite significantly decreased sensitivity to doxorubicin (Dox) and to the etoposide, VP-16, the drug-selected line was essentially equally as sensitive to treatment with exogenous ceramide (Cer), sphingosine (Sp) or dimethyl-sphingosine (DMSP) as the parental line. Next, we observed that high BCL-2-expressing human H69 SCLC cells, that were approximately 160-fold more sensitive to Dox than their combined BCL-2 and MRP-over-expressing (H69AR) counterparts, were only approximately 5-fold more resistant to DMSP. Time-lapse fluorescence microscopy of either UMCC cell line treated with DMSP-Coumarin revealed comparable extents and kinetics of SL uptake, further ruling out MRP-mediated effects on drug uptake. DMSP potentiated the cytotoxic activity of VP-16 and Taxol, but not Dox, in drug-resistant UMCC-1/VP cells. However, this sensitization did not appear to involve DMSP-mediated effects on the function of MRP in drug export; nor did DMSP strongly shift the balance of pro-apoptotic Sps and anti-apoptotic Sp-1-Ps in these cells. We conclude that SL-induced apoptosis markedly overcomes or bypasses MRP-mediated drug resistance relevant to SCLC and may suggest a novel therapeutic approach to chemotherapy for these tumors.

  12. Induction of apoptosis in HepG2 cells by solanine and Bcl-2 protein.

    PubMed

    Ji, Y B; Gao, S Y; Ji, C F; Zou, X

    2008-01-17

    The nightshade (Solanum nigrum Linn.) has been widely used in Chinese traditional medicine as a remedy for the treatment of digestive system cancer. The anti-tumor activity of solanine, a steroid alkaloid isolated from the nightshade has been demonstrated. To observe the effect of anti-tumor and mechanism of solanine. The MTT assay was used to evaluate the IC(50) on the three digestive system tumor cell lines. The effect on the morphology was observed with a laser confocal microscopy; the rate of apoptosis and the cell cycle were measured using flow cytometry (FCM); the expression of Bcl-2 protein was measured by Western blot. The results show that the IC(50) for HepG(2), SGC-7901, and LS-174 were 14.47, >50, and >50 microg/ml, respectively; the morphology of cells in the negative control was normal; for the treated groups, typical signs for apoptosis were found. The rate of apoptosis in HepG(2) cells induced by solanine was found to be 6.0, 14.4, 17.3, 18.9, and 32.2%, respectively. Observation of the cell cycle showed that cells in the G(2)/M phases disappeared while the number of cells in the S phase increased significantly for treated groups. Western blot showed that solanine decreased the expression of Bcl-2 protein. Therefore, the target of solanine in inducing apoptosis in HepG(2) cells seems to be mediated by the inhibition in the expression of Bcl-2 protein.

  13. Prevalence of BCL-2/J(H) Translocation in Healthy African Americans.

    PubMed

    Colon-Otero, Gerardo; Van Wier, Scott A; Ahmann, Greg J; Braggio, Esteban; Albertie, Monica L; Weis, Jennifer A; Ailawadhi, Sikander; Cerhan, James R; Vishnu, Prakash; Jorgensen, Matthew S; Foran, James M; Thomas, Colleen S; Fonseca, Rafael

    2017-01-01

    The translocation t(14;18)(q32;q21) (BCL-2/J(H)) is present in over 80 % of all follicular lymphomas and is detectable in peripheral blood lymphocytes (PBL) of healthy individuals. The prevalence of this translocation has not been studied in African Americans (AAs). Given the higher incidence of follicular lymphomas in whites compared to AAs in the United States (USA), we hypothesized that the translocation prevalence in the blood of AAs would be lower. DNA was isolated from PBL from blood samples collected from participants from FL. Polymerase chain reaction was performed on the BCL-2/J(H) major (MBC) and minor breakpoint cluster (mBC) regions. Eight of the 77 (10.4 %) blood samples from AA participants were positive for MBC (95 % CI, 4.6-19.5 %), and three (3.9 %) were positive for mBC (95 % CI, 0.81-10.97 %) of BCL-2/J(H), with a total of 11 (14.3 %) participants with positive samples (95 % CI, 7.35-24.13 %). In 167 white patient samples, 22 (13.2 %; 95 % CI, 8.44-19.26 %) were positive for MBC, and five (3.0 %; 95 % CI, 0.98-6.85 %) were positive for mBC, with a total of 25 (15 %) participants with positive samples (CI, 9.93-21.30 %). The prevalence of t(14;18)(q32;q21) is not significantly different among AAs and whites from the USA. The lower prevalence of follicular lymphomas in AAs compared with whites is likely a result of differences in secondary molecular alterations involved in follicular lymphoma development. This study is the first report of prevalence of t(14;18) in an AA cohort.

  14. Berberine Inhibits Doxorubicin-Triggered Cardiomyocyte Apoptosis via Attenuating Mitochondrial Dysfunction and Increasing Bcl-2 Expression

    PubMed Central

    Lv, Xiuxiu; Yu, Xiaohui; Wang, Yiyang; Wang, Faqiang; Li, Hongmei; Wang, Yanping; Lu, Daxiang; Qi, Renbin; Wang, Huadong

    2012-01-01

    Cardiomyocyte apoptosis is an important event in doxorubicin (DOX)-induced cardiac injury. The aim of the present study was to investigate the protection of berberine (Ber) against DOX- triggered cardiomyocyte apoptosis in neonatal rat cardiomyocytes and rats. In neonatal rat cardiomyocytes, Ber attenuated DOX-induced cellular injury and apoptosis in a dose-dependent manner. However, Ber has no significant effect on viability of MCF-7 breast cancer cells treated with DOX. Ber reduced caspase-3 and caspase-9, but not caspase-8 activity in DOX-treated cardiomyocytes. Furthermore, Ber decreased adenosine monophosphate-activated protein kinase α (AMPKα) and p53 phosphorylation at 2 h, cytosolic cytochrome c and mitochondrial Bax levels and increased Bcl-2 level at 6 h in DOX-stimulated cardiomyocytes. Pretreatment with compound C, an AMPK inhibitor, also suppressed p53 phosphorylation and apoptosis in DOX-treated cardiomyocytes. DOX stimulation for 30 min led to a loss of mitochondrial membrane potential and a rise in the AMP/ATP ratio. Ber markedly reduced DOX-induced mitochondrial membrane potential loss and an increase in the AMP/ATP ratio at 1 h and 2 h post DOX exposure. In in vivo experiments, Ber significantly improved survival, increased stroke volume and attenuated myocardial injury in DOX-challenged rats. TUNEL and Western blot assays showed that Ber not only decreased myocardial apoptosis, caspase-3 activation, AMPKα and p53 phosphorylation, but also increased Bcl-2 expression in myocardium of rats exposed to DOX for 84 h. These findings indicate that Ber attenuates DOX-induced cardiomyocyte apoptosis via protecting mitochondria, inhibiting an increase in the AMP/ATP ratio and AMPKα phosphorylation as well as elevating Bcl-2 expression, which offer a novel mechanism responsible for protection of Ber against DOX-induced cardiomyopathy. PMID:23077597

  15. Disturbance of Bcl-2, Bax, Caspase-3, Ki-67 and C-myc expression in acute and subchronic exposure to benzo(a)pyrene in cervix.

    PubMed

    Gao, Meili; Li, Yongfei; Ji, Xiaoying; Xue, Xiaochang; Chen, Lan; Feng, Guodong; Zhang, Huqin; Wang, Huichun; Shah, Walayat; Hou, Zhanwu; Kong, Yu

    2016-03-01

    Epidemiological studies have demonstrated that cigarette smoking is an important cofactor or an independent risk factor for the development of cervical cancer. Benzo(a)pyrene (BaP) is one of the most potent tobacco smoke carcinogens in tobacco smoke. BaP induced DNA damage and over expression in p53 cervical tissue of mice as demonstrated in our previous study. Here we present the findings of exposure to BaP on the expression of Bcl-2, C-myc, Ki-67, Caspase-3 and Bax genes in mouse cervix. Acute intraperitoneal administration of BaP (12.5, 25, 50, 100mg/kg body weight) to ICR female mice induced a significant increase in Bcl-2, C-myc, Ki-67 mRNA and protein level till 72h except in Bcl-2 at 24h with 12.5, 25, 50mg/kg as well as at 48h with 12.5mg/kg body weight post treatment. A significant increase was also seen in Caspase-3 and Bax mRNA and protein level with peak level at 24h and gradual decrease till 72h, however, the expression of caspase-3 increased while that of Bax decreased with increasing dose of Bap after 24h. In sub chronic intraperitoneal and oral gavage administration of BaP (2.5, 5, 10mg/kg body weight), similar significant increase was observed for all the examined genes as compared to the control and vehicle groups, however the expression of Bax decreased in a dose dependent manner. The findings of this study will help in further understanding the molecular mechanism of BaP induced carcinogenesis of cervical cancer.

  16. Association of BCL2-938C>A genetic polymorphism with glioma risk in Chinese Han population.

    PubMed

    Li, Wei; Qian, Chunfa; Wang, Linxiong; Teng, Hong; Zhang, Li

    2014-03-01

    Glioma is the most common type of primary brain malignancy in adults. The anti-apoptotic protein B-cell lymphoma 2 (BCL2) has been implicated in the pathogenesis of glioma. This study aimed to evaluate the potential association between BCL2-938C>A genetic polymorphism and glioma susceptibility. This case-control study was conducted in Chinese Han populations consisting of 248 glioma cases and 252 cancer-free controls. The BCL2-938C>A genetic polymorphism was detected by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and verified using DNA sequencing methods. Our data suggested that the genotype/allele of BCL2-938C>A polymorphism were statistically associated with the increased risk of glioma where the risk of glioma for genotype AA or allele A is significantly higher than wild genotype CC (odds ratio (OR) = 2.23, 95% confidence interval (CI) 1.21-4.10, p = 0.009) or allele C (OR = 1.39, 95% CI 1.06-1.82, p = 0.016), respectively. In addition, the BCL2-938AA genotype was significantly more common in patients with glioblastoma and in patients with grade IV glioma. Our findings indicate that the BCL2-938C>A polymorphism is associated with the susceptibility to glioma in Chinese Han populations and might be used as molecular markers for evaluating glioma risk.

  17. Synthesis and Characterization of Novel 2-Amino-Chromene-Nitriles that Target Bcl-2 in Acute Myeloid Leukemia Cell Lines

    PubMed Central

    Mohan, Chakrabhavi D.; Madan, Vikas; Kanojia, Deepika; Shobith, Rangappa; Nanjundaswamy, Shivananju; Mason, Daniel J.; Bender, Andreas; Basappa; Rangappa, Kanchugarakoppal S.; Koeffler, H. Phillip

    2014-01-01

    The anti-apoptotic protein Bcl-2 is a well-known and attractive therapeutic target for cancer. In the present study the solution-phase T3P-DMSO mediated efficient synthesis of 2-amino-chromene-3-carbonitriles from alcohols, malanonitrile and phenols is reported. These novel 2-amino-chromene-3-carbonitriles showed cytotoxicity in human acute myeloid leukemia (AML) cell lines. Compound 4g was found to be the most bioactive, decreasing growth and increasing apoptosis of AML cells. Moreover, compound 4g (at a concentration of 5 µM) increased the G2/M and sub-G1 (apoptosis) phases of AML cells. The AML cells treated with compound 4g exhibited decreased levels of Bcl-2 and increased levels of caspase-9. In silico molecular interaction analysis showed that compound 4g shared a similar global binding motif with navitoclax (another small molecule that binds Bcl-2), however compound 4g occupies a smaller volume within the P2 hot spot of Bcl-2. The intermolecular π-stacking interaction, direct electrostatic interactions, and docking energy predicted for 4g in complex with Bcl-2 suggest a strong affinity of the complex, rendering 4g as a promising Bcl-2 inhibitor for evaluation as a new anticancer agent. PMID:25268519

  18. Bacteria- and IMD Pathway-Independent Immune Defenses against Plasmodium falciparum in Anopheles gambiae

    PubMed Central

    Blumberg, Benjamin J.; Trop, Stefanie; Das, Suchismita; Dimopoulos, George

    2013-01-01

    The mosquito Anopheles gambiae uses its innate immune system to control bacterial and Plasmodium infection of its midgut tissue. The activation of potent IMD pathway-mediated anti-Plasmodium falciparum defenses is dependent on the presence of the midgut microbiota, which activate this defense system upon parasite infection through a peptidoglycan recognition protein, PGRPLC. We employed transcriptomic and reverse genetic analyses to compare the P. falciparum infection-responsive transcriptomes of septic and aseptic mosquitoes and to determine whether bacteria-independent anti-Plasmodium defenses exist. Antibiotic treated aseptic mosquitoes mounted molecular immune responses representing a variety of immune functions upon P. falciparum infection. Among other immune factors, our analysis uncovered a serine protease inhibitor (SRPN7) and Clip-domain serine protease (CLIPC2) that were transcriptionally induced in the midgut upon P. falciparum infection, independent of bacteria. We also showed that SRPN7 negatively and CLIPC2 positively regulate the anti-Plasmodium defense, independently of the midgut-associated bacteria. Co-silencing assays suggested that these two genes may function together in a signaling cascade. Neither gene was regulated, nor modulated, by infection with the rodent malaria parasite Plasmodium berghei, suggesting that SRPN7 and CLIPC2 are components of a defense system with preferential activity towards P. falciparum. Further analysis using RNA interference determined that these genes do not regulate the anti-Plasmodium defense mediated by the IMD pathway, and both factors act as agonists of the endogenous midgut microbiota, further demonstrating the lack of functional relatedness between these genes and the bacteria-dependent activation of the IMD pathway. This is the first study confirming the existence of a bacteria-independent, anti-P. falciparum defense. Further exploration of this anti-Plasmodium defense will help clarify determinants of

  19. Upregulation of macrophage-specific functions by oxidized LDL: lysosomal degradation-dependent and -independent pathways.

    PubMed

    Radhika, A; Sudhakaran, P R

    2013-01-01

    Formation of foam cells from macrophages, which are formed by the differentiation of blood-borne monocytes, is a critical early event in atherogenesis. To examine how pre-exposure of monocytes to modified proteins, such as oxLDL, influences their differentiation to macrophages, an in vitro model system using isolated PBMC maintained in culture in the presence of oxLDL was used. Pretreatment of monocytes with oxLDL caused a faster rate of expression of macrophage-specific functions and loss of monocyte-specific functions compared to unmodified LDL. The effect of oxidation of lipid component of LDL by CuSO(4) and its protein component by HOCl, on mo-mϕ differentiation was studied by monitoring the upregulation of macrophage-specific functions, particularly MMP-9. Chloroquine, a lysosomal degradation blocker, significantly reversed the effect mediated by CuSO(4) oxLDL, indicating the involvement of lysosomal degradation products, while no such effect was observed in HOCl oxLDL-treated cells, indicating the existence of a pathway independent of its lysosomal degradation products. Reversal of the effect of oxLDL by NAC and Calphostin C, an inhibitor of PKC, suggested the activation of RO-mediated signaling pathways. Use of inhibitors of signaling pathways showed that CuSO(4) oxLDL upregulated mϕ-specific MMP-9 through p38 MAPK and Akt-dependent pathways, while HOCl oxLDL utilized ERK ½ and Akt. Further analysis showed the activation of PPARγ and AP-1 in CuSO(4) oxLDL, while HOCl-oxLDL-mediated effect involved NFκB and AP-1. These results suggest that lipid oxLDL- and protein oxLDL-mediated upregulation of mo-mϕ-specific functions involve lysosomal degradation-dependent and -independent activation of intracellular signaling pathways.

  20. From molecular PDT damage to cellular PDT responses: attempts at bridging the gap on the role of Bcl-2

    NASA Astrophysics Data System (ADS)

    Usuda, Jitsuo; Xue, Liang-yan; Chiu, Song-mao; Azizuddin, Kashif; Morris, Rachel L.; Mulvihill, John; Oleinick, Nancy L.

    2003-06-01

    Expression of the anti-apoptotic proteins Bcl-2 and/or Bcl-xL is greatly elevated in many advanced cancers, especially those resistant to standard therapies, such as radiation or chemotherapy. It has been suggested that those two proteins would be attractive targets for the development of new cancer treatments. Photodynamic therapy (PDT) with photosensitizers that localize in or target mitochondria, such as the phthalocyanine Pc 4, specifically attack the anti-apoptotic protein Bcl-2, generating a variety of oxidized, complexed, and cleaved photoproducts. The closely related protein Bcl-xL is also a target of Pc 4-PDT. In a recent study employing transient transfection of an expression vector encoding deletion mutants of Bcl-2, we identified the membrane anchorage regions of the protein that are required to form the photosensitive target. In spite of the demonstrated photodamage to Bcl-2 (and Bcl-xL), how the photodamage translates into changes in the sensitivity of cells to PDT-induced apoptosis or other modes of cell death is not clear, and it also remains unclear how elevated amounts of anti-apoptotic proteins in tumors might make them more or less responsive to PDT. In the present study, we have studied the PDT response of MCF7 human breast cancer cells overexpressing wild-type Bcl-2 or certain deletion mutants either in a transient or stable mode. We show that cells expressing modestly elevated amounts (<10-fold increase) of Bcl-2 and in which the pro-apoptotic protein Bax is not upregulated do not differ from the parental cells with respect to PDT-induced cell killing. In contrast, cells expressing higher amounts (>50-fold increase) of Bcl-2 or certain mutants are made significantly more resistant to the induction of apoptosis and the loss of clonogenicity upon exposure to Pc 4-PDT. In the presence of high levels of Bcl-2, extensive photodamage requires higher PDT doses. We conclude that Pc 4-PDT targets Bcl-2 and Bcl-xL, eliminating one mechanism that

  1. Human Cytomegalovirus Promotes Survival of Infected Monocytes via a Distinct Temporal Regulation of Cellular Bcl-2 Family Proteins

    PubMed Central

    Collins-McMillen, Donna; Kim, Jung Heon; Nogalski, Maciej T.; Stevenson, Emily V.; Caskey, Joshua R.; Cieply, Stephen J.

    2015-01-01

    ABSTRACT Monocytes play a key role in the hematogenous dissemination of human cytomegalovirus (HCMV) to target organ systems. To infect monocytes and reprogram them to deliver infectious virus, HCMV must overcome biological obstacles, including the short life span of monocytes and their antiviral proapoptotic response to infection. We have shown that virally induced upregulation of cellular Mcl-1 promotes early survival of HCMV-infected monocytes, allowing cells to overcome an early apoptotic checkpoint at around 48 h postinfection (hpi). Here, we demonstrate an HCMV-dependent shift from Mcl-1 as the primary antiapoptotic player to the related protein, Bcl-2, later during infection. Bcl-2 was upregulated in HCMV-infected monocytes beginning at 48 hpi. Treatment with the Bcl-2 antagonist ABT-199 only reduced the prosurvival effects of HCMV in target monocytes beginning at 48 hpi, suggesting that Mcl-1 controls survival prior to 48 hpi, while Bcl-2 promotes survival after 48 hpi. Although Bcl-2 was upregulated following viral binding/signaling through cellular integrins (compared to Mcl-1, which is upregulated through binding/activation of epidermal growth factor receptor [EGFR]), it functioned similarly to Mcl-1, adopting the early role of Mcl-1 in preventing caspase-3 cleavage/activation. This distinct, HCMV-induced shift from Mcl-1 to Bcl-2 occurs in response to a cellular upregulation of proapoptotic Bax, as small interfering RNA (siRNA)-mediated knockdown of Bax reduced the upregulation of Bcl-2 in infected monocytes and rescued the cells from the apoptotic effects of Bcl-2 inhibition. Our data demonstrate a distinct survival strategy whereby HCMV induces a biphasic regulation of cellular Bcl-2 proteins to promote host cell survival, leading to viral dissemination and the establishment of persistent HCMV infection. IMPORTANCE Hematogenous dissemination of HCMV via infected monocytes is a crucial component of the viral survival strategy and is required for the

  2. TARGETING THE MITOCHONDRIA ACTIVATES TWO INDEPENDENT CELL DEATH PATHWAYS IN THE OVARIAN CANCER STEM CELLS

    PubMed Central

    Alvero, Ayesha B.; Montagna, Michele K.; Holmberg, Jennie C.; Craveiro, Vinicius; Brown, David; Mor, Gil

    2013-01-01

    Cancer stem cells are responsible for tumor initiation and chemo-resistance. In ovarian cancer, the CD44+/MyD88+ ovarian cancer stem cells (OCSCs) are also able to repair the tumor and serve as tumor vascular progenitors. Targeting these cells is therefore necessary to improve treatment outcome and patient survival. The previous demonstration that the OCSCs are resistant to apoptotic cell death induced by conventional chemotherapy agents suggests that other forms of targeted therapy should be explored. We show in this study that targeting mitochondrial bioenergetics is a potent stimulus to induce caspase-independent cell death in a panel of OCSCs. Treatment of these cells with the novel isoflavone derivative, NV-128, significantly depressed mitochondrial function exhibited by decrease in ATP, Cox-I, and Cox-IV levels, and increase in mitochondrial superoxide and hydrogen peroxide. This promotes a state of “cellular starvation” that activates two independent pathways: 1) AMPKα1 pathway leading to mTOR inhibition; and 2) mitochondrial MEK/ERK pathway leading to loss of mitochondrial membrane potential. The demonstration that a compound can specifically target the mitochondria to induce cell death in this otherwise chemo-resistant cell population opens a new venue for treating ovarian cancer patients. PMID:21677151

  3. ARGONAUTE1 acts in Arabidopsis root radial pattern formation independently of the SHR/SCR pathway.

    PubMed

    Miyashima, Shunsuke; Hashimoto, Takashi; Nakajima, Keiji

    2009-03-01

    The formation of radially symmetric tissue patterns is one of the most basic processes in the development of vascular plants. In Arabidopsis thaliana, plant-specific GRAS-type transcription factors, SHORT-ROOT (SHR) and SCARECROW (SCR), are required for asymmetric cell divisions that separate two ground tissue cell layers, the endodermis and cortex, as well as for endodermal cell fate specification. While loss of SHR or SCR results in a single-layered ground tissue, radially symmetric cellular patterns are still maintained, suggesting that unknown regulatory mechanisms act independently of the SHR/SCR-dependent pathway. In this study, we identified a novel root radial pattern mutant and found that it is a new argonaute1 (ago1) allele. Multiple ago1 mutant alleles contained supernumerary ground tissue cell layers lacking a concentric organization, while expression patterns of SHR and SCR were not affected, revealing a previously unreported role for AGO1 in root ground tissue patterning. Analyses of ago1 scr double mutants demonstrated that the simultaneous loss of the two pathways caused a dramatic reduction in cellular organization and ground tissue identity as compared with the single mutants. Based on these results, we propose that highly symmetric root ground tissue patterns are maintained by the actions of two independent pathways, one using post-transcriptional regulation mediated by AGO1 and the other using the SHR/SCR transcriptional regulator.

  4. Functional Identification of Novel Genes Involved in the Glutathione-Independent Gentisate Pathway in Corynebacterium glutamicum

    PubMed Central

    Shen, Xi-Hui; Jiang, Cheng-Ying; Huang, Yan; Liu, Zhi-Pei; Liu, Shuang-Jiang

    2005-01-01

    Corynebacterium glutamicum used gentisate and 3-hydroxybenzoate as its sole carbon and energy source for growth. By genome-wide data mining, a gene cluster designated ncg12918-ncg12923 was proposed to encode putative proteins involved in gentisate/3-hydroxybenzoate pathway. Genes encoding gentisate 1,2-dioxygenase (ncg12920) and fumarylpyruvate hydrolase (ncg12919) were identified by cloning and expression of each gene in Escherichia coli. The gene of ncg12918 encoding a hypothetical protein (Ncg12918) was proved to be essential for gentisate-3-hydroxybenzoate assimilation. Mutant strain RES167Δncg12918 lost the ability to grow on gentisate or 3-hydroxybenzoate, but this ability could be restored in C. glutamicum upon the complementation with pXMJ19-ncg12918. Cloning and expression of this ncg12918 gene in E. coli showed that Ncg12918 is a glutathione-independent maleylpyruvate isomerase. Upstream of ncg12920, the genes ncg12921-ncg12923 were located, which were essential for gentisate and/or 3-hydroxybenzoate catabolism. The Ncg12921 was able to up-regulate gentisate 1,2-dioxygenase, maleylpyruvate isomerase, and fumarylpyruvate hydrolase activities. The genes ncg12922 and ncg12923 were deduced to encode a gentisate transporter protein and a 3-hydroxybenzoate hydroxylase, respectively, and were essential for gentisate or 3-hydroxybenzoate assimilation. Based on the results obtained in this study, a GSH-independent gentisate pathway was proposed, and genes involved in this pathway were identified. PMID:16000747

  5. BCL-2 and Bax Expression in Skin Flaps Treated with Finasteride or Azelaic Acid

    PubMed Central

    Ayatollahi, Seyyed Abdulmajid; Ajami, Marjan; Reyhanfard, Hamed; Asadi, Yasin; Nassiri-Kashani, Mansour; Rashighi Firoozabadi, Mehdi; Davoodi, Sayed Hossein; Habibi, Esmaeil; Pazoki-Toroudi, Hamidreza

    2012-01-01

    Despite all modern surgical techniques, skin flap that is considered as the main method in most reconstructive surgeries puts the skin tissue at danger of necrosis and apoptosis derived from ischemia. Therefore, finding a treatment for decreasing the apoptosis derived from flap ischemia will be useful in clinic. In present study, we evaluated the effect of azelaic acid 20% and finasteride on expression of BCL-2 and bax proteins after the skin flap surgery. For this purpose, 21 rats were entered in three groups including control, azelaic acid 20% and finasteride, all experienced skin flap surgery and then flap tissue was assessed for determining the expression of proteins in 5 slices prepared from each rat that were graded between – to +++ scales. Both azelaic acid and finasteride increased the expression of BCL-2 protein (p < 0.05) and decrease the expression of bax protein (p < 0.05). These results suggested an antiapoptotic role for finasteride and azelaic acid in preserving the flap after the ischemia reperfusion insult. PMID:24250563

  6. Heavy smokers have higher bcl-2 mutation frequency and risk for lymphoma than non-smokers

    SciTech Connect

    Liu, Y.; Cortopassi, G.A.; Bell, D.A.

    1994-09-01

    Early detection of cells carrying somatic mutations at oncogenic loci could prove useful for identifying individuals at high risk for cancer and permit intervention prior to the onset of clinically recognizable disease. We have determined the frequency of rare t(14;18)(q32;q21) translocations at the bcl-2 proto-oncogene locus in the peripheral blood of 85 smokers and 35 nonsmokers using a sensitive nested PCR assay. The identical translocation occurs in 85% of follicular lymphoma tumors, and about 50% of all non-Hodgkin`s Lymphoma. Smokers with the highest exposure had a 3.6-fold higher mutation frequency relative to the nonsmokers. Logistic regression analysis showed that of the variables tested (age, race, sex, current smoking, years of smoking, and pack-years), the cumulative smoking measure (pack-years) was the best predictor of t(14;18) frequency (p=0.004). These observations are consistent with two recent epidemiological studies showing 2.3-fold and 3.8-fold increased risk for Non-Hodgkins lymphoma among heavy smokers. The results support the hypothesis that smokers have an increased burden of lymphocytes bearing bcl-2 mutations which raises their individual risk for future lymphoid tumors. We speculate that the increased frequency of oncogenic translocations in smokers may result either from the mutagenic or antigenic activity of cigarette smoke.

  7. Targeting BCL-2 and ABL/LYN in Philadelphia chromosome-positive acute lymphoblastic leukemia.

    PubMed

    Leonard, Jessica T; Rowley, Joelle S J; Eide, Christopher A; Traer, Elie; Hayes-Lattin, Brandon; Loriaux, Marc; Spurgeon, Stephen E; Druker, Brian J; Tyner, Jeffrey W; Chang, Bill H

    2016-08-31

    Treatment of Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph(+)ALL) remains a challenge. Although the addition of targeted tyrosine kinase inhibitors (TKIs) to standard cytotoxic therapy has greatly improved upfront treatment, treatment-related morbidity and mortality remain high. TKI monotherapy provides only temporary responses and renders patients susceptible to the development of TKI resistance. Thus, identifying agents that could enhance the activity of TKIs is urgently needed. Recently, a selective inhibitor of B cell lymphoma 2 (BCL-2), ABT-199 (venetoclax), has shown impressive activity against hematologic malignancies. We demonstrate that the combination of TKIs with venetoclax is highly synergistic in vitro, decreasing cell viability and inducing apoptosis in Ph(+)ALL. Furthermore, the multikinase inhibitors dasatinib and ponatinib appear to have the added advantage of inducing Lck/Yes novel tyrosine kinase (LYN)-mediated proapoptotic BCL-2-like protein 11 (BIM) expression and inhibiting up-regulation of antiapoptotic myeloid cell leukemia 1 (MCL-1), thereby potentially overcoming the development of venetoclax resistance. Evaluation of the dasatinib-venetoclax combination for the treatment of primary Ph(+)ALL patient samples in xenografted immunodeficient mice confirmed the tolerability of this drug combination and demonstrated its superior antileukemic efficacy compared to either agent alone. These data suggest that the combination of dasatinib and venetoclax has the potential to improve the treatment of Ph(+)ALL and should be further evaluated for patient care.

  8. Crebbp loss cooperates with Bcl2 over-expression to promote lymphoma in mice.

    PubMed

    García-Ramírez, Idoia; Tadros, Saber; González-Herrero, Inés; Martín-Lorenzo, Alberto; Rodríguez-Hernández, Guillermo; Moore, Dalia; Ruiz-Roca, Lucía; Blanco, Oscar; Alonso-López, Diego; De Las Rivas, Javier; Hartert, Keenan; Duval, Romain; Klinkebiel, David; Bast, Martin; Vose, Julie; Lunning, Matthew; Fu, Kai; Greiner, Timothy; Rodrigues-Lima, Fernando; Jiménez, Rafael; García Criado, Francisco Javier; García Cenador, María Begoña; Brindle, Paul; Vicente-Dueñas, Carolina; Alizadeh, Ash; Sánchez-García, Isidro; Green, Michael R

    2017-03-13

    CREBBP is targeted by inactivating mutations in follicular lymphoma (FL) and diffuse large B-cell lymphoma (DLBCL). Here, we provide evidence from transgenic mouse models that Crebbp deletion results in deficits in B-cell development and can cooperate with Bcl2 over-expression to promote B-cell lymphoma. Through transcriptional and epigenetic profiling of these B-cells we found that Crebbp inactivation was associated with broad transcriptional alterations, but no changes in the patterns of histone acetylation at the proximal regulatory regions of these genes. However, B-cells with Crebbp inactivation showed high expression of Myc and patterns of altered histone acetylation that were localized to intragenic regions, enriched for Myc DNA binding motifs, and showed Myc binding. Through the analysis of CREBBP mutations from a large cohort of primary human FL and DLBCL, we show a significant difference in the spectrum of CREBBP mutations in these two diseases, with higher frequencies of nonsense/frameshift mutations in DLBCL compared to FL. Together our data therefore provide important links between Crebbp inactivation and Bcl2 dependence, and show a role for Crebbp inactivation in the induction of Myc expression. We suggest this may parallel the role of CREBBP frameshift/nonsense mutations in DLBCL that result in loss of the protein, but may contrast the role of missense mutations in the lysine acetyltransferase domain that are more frequently observed in FL and yield an inactive protein.

  9. Adenovirus vector-mediated Gli1 siRNA induces growth inhibition and apoptosis in human pancreatic cancer with Smo-dependent or Smo-independent Hh pathway activation in vitro and in vivo.

    PubMed

    Guo, Jiefang; Gao, Jun; Li, Zhaoshen; Gong, Yanfang; Man, Xiaohua; Jin, Jing; Wu, Hongyu

    2013-10-10

    Activation of Hedgehog (Hh) signaling pathway is a core molecular mechanism in pancreatic carcinogenesis. However, the inhibition of upstream Hh signals does not inhibit the growth of a subset of pancreatic cancer (PC). This study was to examine the effect of siRNA targeting Gli1, the downstream component of Hh pathway, on PC cells and to provide some insight into the underlying mechanisms. A Gli1siRNA-expressing adenovirus (Ad-U6-Gli1siRNA) was constructed, and its effect on PC cells was investigated in vitro and in vivo. Gli1 was expressed in 83.3% (20/24) PC tissues, whereas no expression was found in normal pancreatic ductal epithelium. Gli1 was expressed in SW1990 and CFPAC cells in which Smo was completely absent, as well as in PaTu8988, Panc-1 and BxPC-3 cells in which Smo was concomitantly present. Ad-U6-Gli1siRNA induced cell growth inhibition, strong G0/G1 cell cycle arrest and apoptosis in all five human PC cell lines. Meanwhile, Ad-U6-Gli1siRNA significantly suppressed the expression of Gli1, Ptch1 and two target genes, Cyclin D2 and Bcl-2, in all five lines. Furthermore, two tumor xenograft nude mice models were established by subcutaneously injecting Smo-positive Panc-1 cells or Smo-negative SW1990 cells. The in vivo experimental results demonstrated that Ad-U6-Gli1siRNA inhibited the growth of both Panc1-derived and SW1990-derived tumors and induced cell apoptosis. Our study indicates that Gli1-targeting siRNA could induce growth inhibition and apoptosis in PC through knockdown of Gli1 and its target genes; and this method may represent a more effective therapeutic strategy for PC with Smo-dependent or Smo-independent Hh pathway activation.

  10. Involvement of p38 MAPK- and JNK-modulated expression of Bcl-2 and Bax in Naja nigricollis CMS-9-induced apoptosis of human leukemia K562 cells.

    PubMed

    Chen, Ying-Jung; Liu, Wen-Hsin; Kao, Pei-Hsiu; Wang, Jeh-Jeng; Chang, Long-Sen

    2010-06-15

    CMS-9, a phospholipase A(2) (PLA(2)) isolated from Naja nigricollis venom, induced apoptosis of human leukemia K562 cells, characterized by mitochondrial depolarization, modulation of Bcl-2 family members, cytochrome c release and activation of caspases 9 and 3. Moreover, an increase in intracellular Ca2+ concentration and the production of reactive oxygen species (ROS) was noted. Pretreatment with BAPTA-AM (Ca2+ chelator) and N-acetylcysteine (NAC, ROS scavenger) proved that Ca2+ was an upstream event in inducing ROS generation. Upon exposure to CMS-9, activation of p38 MAPK and JNK was observed in K562 cells. BAPTA-AM or NAC abrogated CMS-9-elicited p38 MAPK and JNK activation, and rescued viability of CMS-9-treated K562 cells. SB202190 (p38 MAPK inhibitor) and SP600125 (JNK inhibitor) suppressed CMS-9-induced dissipation of mitochondrial membrane potential, Bcl-2 down-regulation, Bax up-regulation and increased mitochondrial translocation of Bax. Inactivation of PLA(2) activity reduced drastically the cytotoxicity of CMS-9, and a combination of lysophosphatidylcholine and stearic acid mimicked the cytotoxic effects of CMS-9. Taken together, our data suggest that CMS-9-induced apoptosis of K562 cells is catalytic activity-dependent and is mediated through mitochondria-mediated death pathway triggered by Ca2+/ROS-evoked p38 MAPK and JNK activation.

  11. Immature thymocytes become sensitive to calcium-mediated apoptosis with the onset of CD8, CD4, and the T cell receptor expression: a role for bcl-2?

    PubMed Central

    1993-01-01

    During intrathymic negative selection by clonal deletion, crosslinking of the T cell receptor (TCR) induces cell death by delivering an apoptotic signal(s) to the nucleus along a calcium-dependent pathway. We investigated the reactivity of early precursor-containing thymocytes to Ca(2+)-induced signals, and discovered a breakpoint in their sensitivity to calcium-mediated cell death (CMCD). CD25+CD8-4- TCR- (triple negative [TN]) thymocytes stimulated with a calcium ionophore maintain their viability and precursor activity. By contrast, their immediate progeny, CD25-CD8lo4loTCR alpha beta lo (triple low [TL]) cells react to calcium elevation by abrogation of precursor activity and apoptotic cell death. This developmental difference is specific for CMCD, since both CD25+TN and CD25-TL cells are susceptible to steroid- induced apoptosis. The presence of bcl-2 mRNA correlates directly to the resistance to CMCD-CD25+ TN cells express it and CD25-TL cells do not. These experiments show that thymocytes become sensitive to Ca(2+)- induced apoptosis as soon as they begin to express molecules that mediate thymic selection, and suggest that a concomitant downregulation of bcl-2 may mediate this phenomenon. PMID:8228820

  12. Immature thymocytes become sensitive to calcium-mediated apoptosis with the onset of CD8, CD4, and the T cell receptor expression: a role for bcl-2?

    PubMed

    Andjelić, S; Jain, N; Nikolić-Zugić, J

    1993-11-01

    During intrathymic negative selection by clonal deletion, crosslinking of the T cell receptor (TCR) induces cell death by delivering an apoptotic signal(s) to the nucleus along a calcium-dependent pathway. We investigated the reactivity of early precursor-containing thymocytes to Ca(2+)-induced signals, and discovered a breakpoint in their sensitivity to calcium-mediated cell death (CMCD). CD25+CD8-4- TCR- (triple negative [TN]) thymocytes stimulated with a calcium ionophore maintain their viability and precursor activity. By contrast, their immediate progeny, CD25-CD8lo4loTCR alpha beta lo (triple low [TL]) cells react to calcium elevation by abrogation of precursor activity and apoptotic cell death. This developmental difference is specific for CMCD, since both CD25+TN and CD25-TL cells are susceptible to steroid-induced apoptosis. The presence of bcl-2 mRNA correlates directly to the resistance to CMCD-CD25+ TN cells express it and CD25-TL cells do not. These experiments show that thymocytes become sensitive to Ca(2+)-induced apoptosis as soon as they begin to express molecules that mediate thymic selection, and suggest that a concomitant downregulation of bcl-2 may mediate this phenomenon.

  13. Biological rational for sequential targeting of Bruton tyrosine kinase and Bcl-2 to overcome CD40-induced ABT-199 resistance in mantle cell lymphoma

    PubMed Central

    Chiron, David; Touzeau, Cyrille; Maïga, Sophie; Moreau, Philippe; Pellat-Deceunynck, Catherine; Le Gouill, Steven; Amiot, Martine

    2015-01-01

    The aggressive biological behavior of mantle cell lymphoma (MCL) and its short response to current treatment highlight a great need for better rational therapy. Herein, we investigate the ability of ABT-199, the Bcl-2-selective BH3 mimetic, to kill MCL cells. Among MCL cell lines tested (n = 8), only three were sensitive (LD50 < 200 nM). In contrast, all primary MCL samples tested (n = 11) were highly sensitive to ABT-199 (LD50 < 10 nM). Mcl-1 and Bcl-xL both confer resistance to ABT-199-specific killing and BCL2/(BCLXL + MCL1) mRNA ratio is a strong predictor of sensitivity. By mimicking the microenvironment through CD40 stimulation, we show that ABT-199 sensitivity is impaired through activation of NF-kB pathway and Bcl-xL up-regulation. We further demonstrate that resistance is rapidly lost when MCL cells detach from CD40L-expressing fibroblasts. It has been reported that ibrutinib induces lymphocytosis in vivo holding off malignant cells from their protective microenvironment. We show here for two patients undergoing ibrutinib therapy that mobilized MCL cells are highly sensitive to ABT-199. These results provide evidence that in situ ABT-199 resistance can be overcome when MCL cells escape from the lymph nodes. Altogether, our data support the clinical application of ABT-199 therapy both as a single agent and in sequential combination with BTK inhibitors. PMID:25797245

  14. Same difference: A pilot study of cyclin D1, bcl-2, AMACR, and ALDH-1 identifies significant differences in expression between primary colon adenocarcinoma and its metastases.

    PubMed

    Oakley, Gerard J; Denning, Krista L; Graffeo, Vincent; Griswold, Doreen C; Davis, Adam R; Brown, Linda G

    2016-11-01

    Tumor heterogeneity implies the possibility of significantly different expression of key pathways between primary and metastatic clones. Colon adenocarcinoma is one of the few tumors where current practice includes resection of primary and isolated organ metastases simultaneously without neoadjuvant therapy. We performed a pilot study on 28 cases of colon adenocarcinoma resected simultaneously with metastases in patients with no history of neoadjuvant therapy. We assayed matched primary and metastatic tumors from each patient with common diagnostic antibodies to Bcl-2, Cyclin D1, AMACR, and ALDH-1 by immunohistochemistry with semi-quantitative interpretation on archived formalin fixed, paraffin embedded samples. We were powered for large, consistent differences between primary and metastatic expression, and found 21 of 28 had a significant difference in expression of at least one of the four proteins, accounting for multiplicity of testing. Cyclin D1 had significantly more cases with differential metastatic:primary expression than would be expected by chance alone (p-value 0.0043), favoring higher expression in the metastatic sample. Bcl-2 and ALDH-1 had trends in this direction (p-value 0.078 each). Proportionately more cases with significant differences were identified when a liver metastasis was tested. We conclude differences in expression between metastatic and primary colon adenocarcinoma within the same patient exist, and may have therapeutic and biomarker testing consequences.

  15. Hydrogen Sulfide Attenuates the Recruitment of CD11b+Gr-1+ Myeloid Cells and Regulates Bax/Bcl-2 Signaling in Myocardial Ischemia Injury

    PubMed Central

    Zhang, Youen; Li, Hua; Zhao, Gang; Sun, Aijun; Zong, Nobel C.; Li, Zhaofeng; Zhu, Hongming; Zou, Yunzeng; Yang, Xiangdong; Ge, Junbo

    2014-01-01

    Hydrogen sulfide, an endogenous signaling molecule, plays an important role in the physiology and pathophysiology of the cardiovascular system. Using a mouse model of myocardial infarction, we investigated the anti-inflammatory and anti-apoptotic effects of the H2S donor sodium hydrosulfide (NaHS). The results demonstrated that the administration of NaHS improved survival, preserved left ventricular function, limited infarct size, and improved H2S levels in cardiac tissue to attenuate the recruitment of CD11b+Gr-1+ myeloid cells and to regulate the Bax/Bcl-2 pathway. Furthermore, the cardioprotective effects of NaHS were enhanced by inhibiting the migration of CD11b+Gr-1+ myeloid cells from the spleen into the blood and by attenuating post-infarction inflammation. These observations suggest that the novel mechanism underlying the cardioprotective function of H2S is secondary to a combination of attenuation the recruitment of CD11b+Gr-1+ myeloid cells and regulation of the Bax/Bcl-2 apoptotic signaling. PMID:24758901

  16. Hexavalent chromium-induced apoptosis of granulosa cells involves selective sub-cellular translocation of Bcl-2 members, ERK1/2 and p53

    SciTech Connect

    Banu, Sakhila K.; Stanley, Jone A.; Lee, JeHoon; Stephen, Sam D.; Arosh, Joe A.; Hoyer, Patricia B.; Burghardt, Robert C.

    2011-03-15

    Hexavalent chromium (CrVI) has been widely used in industries throughout the world. Increased usage of CrVI and atmospheric emission of CrVI from catalytic converters of automobiles, and its improper disposal causes various health hazards including female infertility. Recently we have reported that lactational exposure to CrVI induced a delay/arrest in follicular development at the secondary follicular stage. In order to investigate the underlying mechanism, primary cultures of rat granulosa cells were treated with 10 {mu}M potassium dichromate (CrVI) for 12 and 24 h, with or without vitamin C pre-treatment for 24 h. The effects of CrVI on intrinsic apoptotic pathway(s) were investigated. Our data indicated that CrVI: (i) induced DNA fragmentation and increased apoptosis, (ii) increased cytochrome c release from the mitochondria to cytosol, (iii) downregulated anti-apoptotic Bcl-2, Bcl-XL, HSP70 and HSP90; upregulated pro-apoptotic BAX and BAD, (iv) altered translocation of Bcl-2, Bcl-XL, BAX, BAD, HSP70 and HSP90 to the mitochondria, (v) upregulated p-ERK and p-JNK, and selectively translocated p-ERK to the mitochondria and nucleus, (vi) activated caspase-3 and PARP, and (vii) increased phosphorylation of p53 at ser-6, ser-9, ser-15, ser-20, ser-37, ser-46 and ser-392, increased p53 transcriptional activation, and downregulated MDM-2. Vitamin C pre-treatment mitigated CrVI effects on apoptosis and related pathways. Our study, for the first time provides a clear insight into the effect of CrVI on multiple pathways that lead to apoptosis of granulosa cells which could be mitigated by vitamin C.

  17. Altered expression of Bcl-2 and Bax in follicles within dehydroepiandrosterone-induced polycystic ovaries in rats.

    PubMed

    Bas, Diana; Abramovich, Dalhia; Hernandez, Fatima; Tesone, Marta

    2011-05-01

    PCOS (polycystic ovary syndrome) is a heterogeneous disease characterized by hyperandrogenaemia, hirsutism, oligo- or amenorrhea, insulin resistance and anovulation. The aim of the present study was to evaluate if the balance between the ovarian expression of Bax (proapoptotic protein) and Bcl-2 (antiapoptotic protein) is altered in a PCOS model developed in rats by DHEA (dehydroepiandrosterone) administration. In addition, the ovarian morphology and the circulating progesterone levels were evaluated. Histological studies confirmed the presence of follicular cysts, atretic follicles and the absence of corpora lutea in the ovaries from the PCOS group and a significant decrease in circulating progesterone levels. Immunohistochemical studies showed that the expression of Bcl-2 and Bax were mainly localized in granulosa cells of AFs (antral follicles) in both groups. Bax expression was greater in preantral and AFs from PCOS ovarian sections than in the controls. In contrast, intense Bcl-2 immunostaining was observed in the control AFs, while Bcl-2 protein was either absent in PFs (preantral follicles) or weakly expressed in AFs from PCOS rats. These results were partially confirmed by Western studies. Data revealed that the ovarian level of Bcl-2 protein was lower in PCOS than in the control and that there were no differences in Bax ovarian levels between groups. However, Bax/Bcl-2 ratio was significantly higher in PCOS group than in the control group. In conclusion, an increase in ovarian apoptosis through an imbalance among the Bcl-2 family members may be involved in the transformation of growing follicles in cystic follicles in the ovaries from DHEA-induced PCOS rats.

  18. In vitro arsenic trioxide induces apoptosis in T cells of asthmatic patients by a Bcl-2 related mechanism.

    PubMed

    Qin, Dong-Yun; Huang, Ren; Wu, Tie

    2008-01-01

    This study examined the effects of arsenic trioxide on apoptosis and interleukin-4 release in T cells of asthmatic patients in vitro and investigated the role of Bcl-2 in the active mechanism. T cells were isolated from asthmatic patients (n = 21) and healthy controls (n = 20), and then treated with arsenic trioxide and dexamethasone. Cell apoptosis was measured using fluorescence microscopy, flow cytometry and a cytochrome c ELISA kit. Interleukin-4 levels in the serum and in supernatants from T cells were quantified by ELISA. Flow cytometric analysis and immunofluorescence studies were performed to determine Bcl-2 expression. T cells of the asthmatic patients (i. e. without treatment) exhibited decelerated spontaneous apoptosis after 24 h incubation in vitro when compared to T cells of the healthy controls. With dexamethasone treatment, an increase in apoptosis of T cells was not significantly different between both groups, irrespective of the method used. Arsenic trioxide treatment, however, significantly increased the apoptosis of T cells of the asthmatic group and showed a slight effect on the control group. In asthmatic patients, elevated levels of interleukin-4 and up-regulated Bcl-2 expression were detected. Moreover, in vitro, T cells of asthmatic patients spontaneously released more interleukin-4 and exhibited more Bcl-2 expression than T cells from the control group. Arsenic trioxide treatment significantly decreased interleukin-4 release and down-regulated Bcl-2 expression in asthmatic patients, while it only slightly affected healthy controls. Dexamethasone treatment decreased interleukin-4 release in both groups examined. It did not significantly influence Bcl-2 expression. These results suggest that arsenic trioxide induces T cell apoptosis and decreases interleukin-4 release in T cells of asthmatic patients in vitro and that down-regulation of Bcl-2 expression may be an important mechanism.

  19. Vaccinia Virus Protein A49 Is an Unexpected Member of the B-cell Lymphoma (Bcl)-2 Protein Family*

    PubMed Central

    Neidel, Sarah; Maluquer de Motes, Carlos; Mansur, Daniel S.; Strnadova, Pavla; Smith, Geoffrey L.; Graham, Stephen C.

    2015-01-01

    Vaccinia virus (VACV) encodes several proteins that inhibit activation of the proinflammatory transcription factor nuclear factor κB (NF-κB). VACV protein A49 prevents translocation of NF-κB to the nucleus by sequestering cellular β-TrCP, a protein required for the degradation of the inhibitor of κB. A49 does not share overall sequence similarity with any protein of known structure or function. We solved the crystal structure of A49 from VACV Western Reserve to 1.8 Å resolution and showed, surprisingly, that A49 has the same three-dimensional fold as Bcl-2 family proteins despite lacking identifiable sequence similarity. Whereas Bcl-2 family members characteristically modulate cellular apoptosis, A49 lacks a surface groove suitable for binding BH3 peptides and does not bind proapoptotic Bcl-2 family proteins Bax or Bak. The N-terminal 17 residues of A49 do not adopt a single well ordered conformation, consistent with their proposed role in binding β-TrCP. Whereas pairs of A49 molecules interact symmetrically via a large hydrophobic surface in crystallo, A49 does not dimerize in solution or in cells, and we propose that this hydrophobic interaction surface may mediate binding to a yet undefined cellular partner. A49 represents the eleventh VACV Bcl-2 family protein and, despite these proteins sharing very low sequence identity, structure-based phylogenetic analysis shows that all poxvirus Bcl-2 proteins are structurally more similar to each other than they are to any cellular or herpesvirus Bcl-2 proteins. This is consistent with duplication and diversification of a single BCL2 family gene acquired by an ancestral poxvirus. PMID:25605733

  20. p28 Bap31, a Bcl-2/Bcl-XL- and procaspase-8-associated protein in the endoplasmic reticulum.

    PubMed

    Ng, F W; Nguyen, M; Kwan, T; Branton, P E; Nicholson, D W; Cromlish, J A; Shore, G C

    1997-10-20

    We have identified a human Bcl-2-interacting protein, p28 Bap31. It is a 28-kD (p28) polytopic integral protein of the endoplasmic reticulum whose COOH-terminal cytosolic region contains overlapping predicted leucine zipper and weak death effector homology domains, flanked on either side by identical caspase recognition sites. In cotransfected 293T cells, p28 is part of a complex that includes Bcl-2/Bcl-XL and procaspase-8 (pro-FLICE). Bax, a pro-apoptotic member of the Bcl-2 family, does not associate with the complex; however, it prevents Bcl-2 from doing so. In the absence (but not presence) of elevated Bcl-2 levels, apoptotic signaling by adenovirus E1A oncoproteins promote cleavage of p28 at the two caspase recognition sites. Purified caspase-8 (FLICE/MACH/Mch5) and caspase-1(ICE), but not caspase-3 (CPP32/apopain/ Yama), efficiently catalyze this reaction in vitro. The resulting NH2-terminal p20 fragment induces apoptosis when expressed ectopically in otherwise normal cells. Taken together, the results suggest that p28 Bap31 is part of a complex in the endoplasmic reticulum that mechanically bridges an apoptosis-initiating caspase, like procaspase-8, with the anti-apoptotic regulator Bcl-2 or Bcl-XL. This raises the possibility that the p28 complex contributes to the regulation of procaspase-8 or a related caspase in response to E1A, dependent on the status of the Bcl-2 setpoint within the complex.

  1. (p)ppGpp-dependent and -independent pathways for salt tolerance in Escherichia coli.

    PubMed

    Tarusawa, Takefusa; Ito, Shion; Goto, Simon; Ushida, Chisato; Muto, Akira; Himeno, Hyouta

    2016-07-01

    Addition of some kinds of translation inhibitors targeting the ribosome such as kasugamycin to the culture medium as well as removal of a ribosome maturation factor or a ribosomal protein provides Escherichia coli cells with tolerance to high salt stress. Here, we found that another kind of translation inhibitor, serine hydroxamate (SHX), which induces amino acid starvation leading to (p)ppGpp production, also has a similar effect, but via a different pathway. Unlike kasugamycin, SHX was not effective in (p)ppGpp-null mutant cells. SHX and depletion of RsgA, a ribosome maturation factor, had an additive effect on salt tolerance, while kasugamycin or depletion of RsgA did not. These results indicate the presence of two distinct pathways, (p)ppGpp-dependent and -independent pathways, for salt tolerance of E. coli cell. Both pathways operate even in the absence of σ(S), an alternative sigma factor involved in the stationary phase or stress response. Hastened activation of the exocytoplasmic stress-specific sigma factor, σ(E), after salt shock was observed in the cells treated with SHX, as has been observed in the cells treated with a translation inhibitor or depleted of a ribosome maturation factor.

  2. Possible role of the aromatase-independent steroid metabolism pathways in hormone responsive primary breast cancers.

    PubMed

    Hanamura, Toru; Niwa, Toshifumi; Gohno, Tatsuyuki; Kurosumi, Masafumi; Takei, Hiroyuki; Yamaguchi, Yuri; Ito, Ken-ichi; Hayashi, Shin-ichi

    2014-01-01

    Aromatase inhibitors (AIs) exert antiproliferative effects by reducing local estrogen production from androgens in postmenopausal women with hormone-responsive breast cancer. Previous reports have shown that androgen metabolites generated by the aromatase-independent enzymes, 5α-androstane-3β, 17β-diol (3β-diol), androst-5-ene-3β, and 17β-diol (A-diol), also activate estrogen receptor (ER) α. Estradiol (E2) can also reportedly be generated from estrone sulfate (E1S) pooled in the plasma. Estrogenic steroid-producing aromatase-independent pathways have thus been proposed as a mechanism of AI resistance. However, it is unclear whether these pathways are functional in clinical breast cancer. To investigate this issue, we assessed the transcriptional activities of ER in 45 ER-positive human breast cancers using the adenovirus estrogen-response element-green fluorescent protein assay and mRNA expression levels of the ER target gene, progesterone receptor, as indicators of ex vivo and in vivo ER activity, respectively. We also determined mRNA expression levels of 5α-reductase type 1 (SRD5A1) and 3β-hydroxysteroid dehydrogenase type 1 (3β-HSD type 1; HSD3B1), which produce 3β-diol from androgens, and of steroid sulfatase (STS) and 17β-hydroxysteroid dehydrogenase type 1 (17β-HSD type 1; HSD17B1), which produce E2 or A-diol from E1S or dehydroepiandrosterone sulfate. SRD5A1 and HSD3B1 expression levels were positively correlated with ex vivo and in vivo ER activities. STS and HSD17B1 expression levels were positively correlated with in vivo ER activity alone. Elevated expression levels of these steroid-metabolizing enzymes in association with high in vivo ER activity were particularly notable in postmenopausal patients. Analysis of the expression levels of steroid-metabolizing enzymes revealed positive correlations between SRD5A1 and HSD3B1, and STS and HSD17B1. These findings suggest that the SRD5A1-HSD3B1 as well as the STS-HSD17B pathways, could contributes

  3. Discovery of new selective cytotoxic agents against Bcl-2 expressing cancer cells using ligand-based modeling.

    PubMed

    Aboalhaija, Nour H; Zihlif, Malek A; Taha, Mutasem O

    2016-04-25

    Bcl-2 is an anti-apoptotic protein involved in cancer resistance to cytotoxic therapies making it an interesting target for inhibitors design. Towards this end, we implemented an elaborated ligand-based computational workflow that combines exhaustive pharmacophore modeling and quantitative structure-activity relationship (QSAR) analysis to explore the structural features required for potent Bcl-2 inhibitors employing 98 known Bcl-2 inhibitors. Genetic function algorithm (GFA) coupled with k nearest neighbor (kNN) or multiple linear regression (MLR) analyses were employed to generate predictive QSAR models based on optimal combinations of pharmacophores and physicochemical descriptors. The optimal QSAR-selected pharmacophore models were validated by receiver operating characteristic (ROC) curve analysis and by comparison with crystallographic structures of known inhibitors co-crystallized within Bcl-2 binding pocket. Optimal QSAR models and their associated pharmacophore hypotheses were validated by identification and experimental evaluation of new selective cytotoxic compounds against Bcl-2 expressing cancer cells. The hits were retrieved from the National Cancer Institute (NCI) structural database. Several potent hits were captured. The most potent hits illustrated IC50 values of 4.2 and 2.60 μM against MDA-MB-231 cancer cell-line.

  4. Neonatal motoneurons overexpressing the bcl-2 protooncogene in transgenic mice are protected from axotomy-induced cell death.

    PubMed Central

    Dubois-Dauphin, M; Frankowski, H; Tsujimoto, Y; Huarte, J; Martinou, J C

    1994-01-01

    In vitro, the overexpression of the bcl-2 protooncogene in cultured neurons has been shown to prevent apoptosis induced by neurotrophic factor deprivation. We have generated transgenic mice overexpressing the Bcl-2 protein in neurons, including motoneurons of the facial nucleus. We have tested whether Bcl-2 could protect these motoneurons from experimentally induced cell death in new born mice. To address this question, we performed unilateral lesion of the facial nerve of wild-type and transgenic 2-day-old mice. In wild-type mice, the lesioned nerve and the corresponding motoneuron cell bodies in the facial nucleus underwent rapid degeneration. In contrast, in transgenic mice, facial motoneurons survived axotomy. Not only their cell bodies but also their axons were protected up to the lesion site. These results demonstrate that in vivo Bcl-2 protects neonatal motoneurons from degeneration after axonal injury. A better understanding of the mechanisms by which Bcl-2 prevents neuronal cell death in vivo could lead to the development of strategies for the treatment of motoneuron degenerative diseases. Images PMID:8159744

  5. Nitrogen mustard up-regulates Bcl-2 and GSH and increases NTP and PCr in HT-29 colon cancer cells.

    PubMed Central

    Boddie, A. W.; Constantinou, A.; Williams, C.; Reed, A.

    1998-01-01

    We hypothesized that unexplained increases in nucleoside triphosphates (NTP) observed by 31P magnetic resonance spectroscopy (MRS) after treatment of tumours by DNA-damaging agents were related to chemotherapy-induced up-regulation of the bcl-2 gene and DNA damage prevention and repair processes. To test this hypothesis, we treated HT-29 cells with 10(-4) M nitrogen mustard (HN2) and performed sequential perchloric acid extractions in replicate over 0-18 h. By reference to an internal standard (methylene diphosphonic acid), absolute changes in 31P-detectable high-energy phosphates in these extracts were determined and correlated with changes in bcl-2 protein levels, cell viability, cell cycle, apoptosis and total cellular glutathione (GSH) (an important defence against DNA damage from alkylating agents). After HN2 administration, bcl-2 protein levels in the HT-29 cell line rose at 2 h. Cell viability declined to 25% within 18 h, but apoptosis measured using fluorescence techniques remained in the 1-4% range. Increased cell division was noted at 4 h. Two high-energy interconvertible phosphates, NTP (P < or = 0.006) and phosphocreatine (PCr) (P < or = 0.0002), increased at 2 h concurrently with increased levels of bcl-2 protein and glutathione. This study demonstrates that bcl-2 and glutathione are up-regulated by HN2 and links this to a previously unexplained 31P MRS phenomenon: increased NTP after chemotherapy. Images Figure 6 PMID:9652754

  6. In situ immunohistochemical study of Bcl-2 and heat shock proteins in human corneal endothelial cells during corneal storage

    PubMed Central

    Gain, P.; Thuret, G.; Chiquet, C.; Dumollard, J. M.; Mosnier, J. F.; Campos, L.

    2001-01-01

    AIM—To investigate the expression of Bcl-2 and heat shock proteins (HSPs), which are known to increase cell survival, in human corneal endothelial cells (HCECs) of corneas stored in organ culture.
METHODS—32 paired corneas were randomly assigned to either a short or a long storage time. The flat mounts of endothelium were examined after immunostaining with monoclonal antibodies to Bcl-2 and HSP 27, 60, 70, and 90.
RESULTS—HCECs expressed generally all the proteins studied. Bcl-2 expression was weaker in the long stored corneas (p=0.035). There was no relation between immunostaining, age, sex, or death to culture time. Frequently some Descemet membranes carried negative cells preferentially located in folds and exhibiting morphological changes consistent with swelling cells corresponding to early stages of apoptosis.
CONCLUSION—Expression of these cytoprotective proteins reflects the high level of HCEC resistance to stresses induced by organ culture. The decreased immunostaining of Bcl-2 in the long storage group could act in cellular loss currently observed with storage time. The negativity of Bcl-2 and HSP labelling in corneal folding may be related to apoptosis.

 PMID:11466261

  7. Expression of the Mir-133 and Bcl-2 could be affected by swimming training in the heart of ovariectomized rats

    PubMed Central

    Habibi, Parisa; Alihemmati, Alireza; NourAzar, Alireza; Yousefi, Hadi; Mortazavi, Safieh; Ahmadiasl, Nasser

    2016-01-01

    Objective(s): The beneficial and more potent role of exercise to prevent heart apoptosis in ovariectomized rats has been known. The aim of this study was to examine the effects of swimming training on cardiac expression of Bcl-2, and Mir-133 levels and glycogen changes in the myocyte. Materials and Methods: Forty animals were separated into four groups as control, sham, ovariectomy (OVX) and ovariectomized group with 8 weeks swimming training (OVX.E). Training effects were evaluated by measuring lipid profiles, Bcl-2 and Mir-133 expression levels in the cardiac tissue. Grafts were analyzed by reverse transcription–polymerase chain reaction for Bcl-2 mRNA and Mir-133 and by Western blot for Bcl-2 protein. Results: Ovariectomy down-regulated Bcl-2 and Mir-133 expression levels in the cardiac tissue, and swimming training up-regulated their expression significantly (P<0.05). Conclusion: Our results showed that regular exercise as a physical replacement therapy could prevent and improve the effects of estrogen deficiency in the cardia. PMID:27279981

  8. Synergistic cytotoxicity of bcl-2 antisense oligodeoxynucleotides and etoposide, doxorubicin and cisplatin on small-cell lung cancer cell lines.

    PubMed Central

    Zangemeister-Wittke, U.; Schenker, T.; Luedke, G. H.; Stahel, R. A.

    1998-01-01

    Expression of Bcl-2 is life-sustaining for small-cell lung cancer cells and associated with drug resistance. In the present study, the interactions between the bcl-2 antisense oligodeoxynucleotide 2009 and the chemotherapeutic agents etoposide, doxorubicin and cisplatin were investigated on small-cell lung cancer cell lines to search for synergistic combinations. The cell lines NCI-H69, SW2 and NCI-H82 express high, intermediate-high and low basal levels of Bcl-2, respectively, which are inversely correlated with the sensitivities of the cell lines to treatment with oligodeoxynucleotide 2009 and the chemotherapeutic agents alone. Moreover, differences were found in the responsiveness of the cell lines to treatment with combinations of oligodeoxynucleotide 2009 and the chemotherapeutic agents. In the cell lines NCI-H69 and SW2, all combinations resulted in synergistic cytotoxicity. In NCI-H69 cells, maximum synergy with a combination index of 0.2 was achieved with the combination of oligodeoxynucleotide 2009 and etoposide. In SW2 cells, the combination of oligodeoxynucleotide 2009 and doxorubicin was the most effective (combination index = 0.5). In the cell line NCI-H82, which expresses a low basal level of Bcl-2, most of the combinations were slightly antagonistic. Our data suggest the use of oligodeoxynucleotide 2009 in combination with chemotherapy for the treatment of small-cell lung cancer that overexpresses Bcl-2. Images Figure 1 PMID:9792147

  9. Bcl-2 proteins bid and bax form a network to permeabilize the mitochondria at the onset of apoptosis

    PubMed Central

    Gahl, Robert F; Dwivedi, Pallavi; Tjandra, Nico

    2016-01-01

    The most critical step in the initiation of apoptosis is the activation of the Bcl-2 family of proteins to oligomerize and permeabilize the outer-mitochondrial membrane (OMM). As this step results in the irreversible release of factors that enhance cellular degradation, it is the point of no return in programmed cell death and would be an ideal therapeutic target. However, the arrangement of the Bcl-2 proteins in the OMM during permeabilization still remains unknown. It is also unclear whether the Bcl-2 protein, Bid, directly participates in the formation of the oligomers in live cells, even though it is cleaved and translocates to the OMM at the initiation of apoptosis. Therefore, we utilized confocal microscopy to measure Förster resonance energy transfer (FRET) efficiencies in live cells to determine the conformation(s) and intermolecular contacts of Bid within these Bcl-2 oligomers. We found that Bid adopts an extended conformation, which appears to be critical for its association with the mitochondrial membrane. This conformation is also important for intermolecular contacts within the Bid oligomer. More importantly for the first time, direct intermolecular contacts between Bid and Bax were observed, thereby, confirming Bid as a key component of these oligomers. Furthermore, the observed FRET efficiencies allowed us to propose an oligomeric arrangement of Bid, Bax, and possibly other members of the Bcl-2 family of proteins that form a self-propagating network that permeabilizes the OMM. PMID:27763642