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Sample records for bcl-2 regulated apoptosis

  1. Structural studies of Bcl-2-family regulators of apoptosis

    SciTech Connect

    Stevens, P.W. |; Cai, X.; Schiffer, M.

    1996-06-01

    The Bcl-2 family of proteins includes about a dozen different proteins which share two small regions of amino acid homology but otherwise exhibit rather modest sequence similarities. The members of this family function as molecular regulators of apoptosis, some as accelerators of cell death and others as inhibitors of apoptosis. The authors analyzed the predicted secondary structures of Bcl-2-family proteins and found that a series of four amphipathic helices, three short {beta}-strands, and a carboxyl-terminal transmembrane helix were conserved throughout the family. Since the Bcl-2-family proteins do not have homology with any proteins of known three-dimensional structure, it seems likely that the tertiary structure assumed by these conserved Bcl-2-family structural elements will represent a completely new protein fold. The authors have prepared recombinant versions of particular proteins of the Bcl-2-family so that the can analyze their molecular structures experimentally. In addition, since some of the Bcl-2-family members homodimerize, they are using small-zone size-exclusion chromatography to analyze the homodimerization of individual, purified Bcl-2-family proteins in order to determine the association and rate constants for these dimerization reactions using computer-simulation methods previously developed in the group. Since certain of these proteins also interest with each other to form heterodimers, the authors also hope to extend the analyses to similarly analyze the heterodimerization of pairs of purified Bcl-2-family proteins.

  2. 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

  3. 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.

  4. 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.

  5. 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.

  6. Telmisartan induces apoptosis and regulates Bcl-2 in human renal cancer cells

    PubMed Central

    Leitão Oliveira, Ana Luiza CS; de Melo Silveira, Raniere Fagundes; de Oliveira Rocha, Hugo Alexandre; de França Cavalcanti, Pedro; de Araújo, Aurigena Antunes

    2015-01-01

    It has been well-characterized that the renin-angiotensin system (RAS) physiologically regulates systemic arterial pressure. However, RAS signaling has also been shown to increase cell proliferation during malignancy, and angiotensin receptor blockers (ARBs) are able to decrease pro-survival signaling by inhibiting anti-apoptotic molecules and suppressing caspase activity. In this study, the apoptotic effects of telmisartan, a type of ARB, was evaluated using a non-cancerous human renal cell line (HEK) and a human renal cell carcinoma (RCC) cell line (786). Both types of cells were treated with telmisartan for 4 h, 24 h, and 48 h, and then were assayed for levels of apoptosis, caspase-3, and Bcl-2 using MTT assays, flow cytometry, and immunostaining studies. Analysis of variance was used to identify significant differences between these data (P < 0.05). Following the treatment of 786 cells with 100 µM and 200 µM telmisartan, a marked inhibition of cell proliferation was observed. 50 µM cisplatin also caused high inhibition of these cells. Moreover, these inhibitions were both concentration- and time-dependent (P < 0.05). Various apoptotic effects were also observed compared with control cells at the 24 h and 48 h timepoints assayed (P < 0.001). Furthermore, positive caspase-3 staining and down-regulation of Bcl-2 were detected, consistent with induction of cell death. In contrast, treatment of HEK cells with telmisartan did not produce an apoptotic effect compared with control cells at the 24 h timepoint (P > 0.05). Treatment with cisplatin promoted in HEK cells high index of apoptosis (P < 0.001). Taken together, these results suggest that telmisartan induces apoptosis via down-regulation of Bcl-2 and involvement of caspase-3 in human RCC cells. PMID:25125501

  7. 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.

  8. Telmisartan induces apoptosis and regulates Bcl-2 in human renal cancer cells.

    PubMed

    de Araújo Júnior, Raimundo Fernandes; Leitão Oliveira, Ana Luiza C S; de Melo Silveira, Raniere Fagundes; de Oliveira Rocha, Hugo Alexandre; de França Cavalcanti, Pedro; de Araújo, Aurigena Antunes

    2015-01-01

    It has been well-characterized that the renin-angiotensin system (RAS) physiologically regulates systemic arterial pressure. However, RAS signaling has also been shown to increase cell proliferation during malignancy, and angiotensin receptor blockers (ARBs) are able to decrease pro-survival signaling by inhibiting anti-apoptotic molecules and suppressing caspase activity. In this study, the apoptotic effects of telmisartan, a type of ARB, was evaluated using a non-cancerous human renal cell line (HEK) and a human renal cell carcinoma (RCC) cell line (786). Both types of cells were treated with telmisartan for 4 h, 24 h, and 48 h, and then were assayed for levels of apoptosis, caspase-3, and Bcl-2 using MTT assays, flow cytometry, and immunostaining studies. Analysis of variance was used to identify significant differences between these data (P < 0.05). Following the treatment of 786 cells with 100 µM and 200 µM telmisartan, a marked inhibition of cell proliferation was observed. 50 µM cisplatin also caused high inhibition of these cells. Moreover, these inhibitions were both concentration- and time-dependent (P < 0.05). Various apoptotic effects were also observed compared with control cells at the 24 h and 48 h timepoints assayed (P < 0.001). Furthermore, positive caspase-3 staining and down-regulation of Bcl-2 were detected, consistent with induction of cell death. In contrast, treatment of HEK cells with telmisartan did not produce an apoptotic effect compared with control cells at the 24 h timepoint (P > 0.05). Treatment with cisplatin promoted in HEK cells high index of apoptosis (P < 0.001). Taken together, these results suggest that telmisartan induces apoptosis via down-regulation of Bcl-2 and involvement of caspase-3 in human RCC cells. © 2014 by the Society for Experimental Biology and Medicine.

  9. Combination of erlotinib and EGCG induces apoptosis of head and neck cancers through posttranscriptional regulation of Bim and Bcl-2.

    PubMed

    Haque, Abedul; Rahman, Mohammad Aminur; Chen, Zhuo Georgia; Saba, Nabil F; Khuri, Fadlo R; Shin, Dong M; Ruhul Amin, A R M

    2015-07-01

    Combinatorial approaches using two or more compounds are gaining increasing attention for cancer therapy. We have previously reported that the combination of the EGFR-TKI erlotinib and epigallocatechin-3-gallate (EGCG) exhibited synergistic chemopreventive effects in head and neck cancers by inducing the expression of Bim, p21, p27, and by inhibiting the phosphorylation of ERK and AKT and expression of Bcl-2. In the current study, we further investigated the mechanism of regulation of Bim, Bcl-2, p21 and p27, and their role in apoptosis. shRNA-mediated silencing of Bim significantly inhibited apoptosis induced by the combination of erlotinib and EGCG (p = 0.005). On the other hand, overexpression of Bcl-2 markedly protected cells from apoptosis (p = 0.003), whereas overexpression of constitutively active AKT only minimally protected cells from apoptosis induced by the combination of the two compounds. Analysis of mRNA expression by RT-PCR revealed that erlotinib, EGCG and their combination had no significant effects on the mRNA expression of Bim, p21, p27 or Bcl-2 suggesting the post-transcriptional regulation of these molecules. Furthermore, we found that erlotinib or the combination of EGCG and erlotinib inhibited the phosphorylation of Bim and stabilized Bim after inhibition of protein translation by cycloheximide. Taken together, our results strongly suggest that the combination of erlotinib and EGCG induces apoptosis of SCCHN cells by regulating Bim and Bcl-2 at the posttranscriptional level.

  10. Simultaneous Detection of Tumor Cell Apoptosis Regulators Bcl-2 and Bax through a Dual-Signal-Marked Electrochemical Immunosensor.

    PubMed

    Zhou, Shiwei; Wang, Yingying; Zhu, Jun-Jie

    2016-03-01

    B-cell lymphoma 2 (Bcl-2) and Bcl-2-associated X protein (Bax) are often used to monitor the apoptosis of tumor cells and evaluate cancer drug effect. In this work, a novel sandwich-type dual-signal-marked electrochemical biosensor was fabricated for simultaneous detection of Bcl-2 and Bax proteins. Reduced graphene oxide (RGO) layers were used as substrate to immobilize Bcl-2 and Bax antibodies for further capturing target antigens. CdSeTe@CdS quantum dots (QDs) and Ag nanoclusters (NCs) with antibody modification and mesoporous silica amplification were used as signal probes, which were proportional to the amount of Bcl-2 and Bax antigens. Mesoporous SiO2 can provide a larger surface area, more effectively charged by ethylene imine polymer or poly(diallyldimethylammonium chloride) to adsorb more probes. The Bcl-2 and Bax proteins were determined indirectly by the detection of oxidation peak currents of Cd and Ag using anodic stripping voltammetry, showing a good linear relationship in the protein concentration range from 1 ng/mL to 250 ng/mL. The detection limit of trace protein level was ∼0.5 fmol. The biosensor was further introduced to investigate Bcl-2 and Bax expressions from nilotinib-treated chronic myeloid leukemia K562 cells. With the increase of drug dosage and incubation time, the up-regulation for Bax and down-regulation for Bcl-2 were observed, which indicated that the apoptosis level of K562 cells could be regulated by Bcl-2 family. The ratio of Bax/Bcl-2 was further calculated for evaluation of its drug effect and apoptosis level. The limited cell amount for detection reached less than 1 × 10(3) cells, much lower than traditional methods. Furthermore, completely independent detection step and stable acid solutions containing Ag(+) and Cd(2+) for long-time storage contribute to reducing the error from the sample differences and avoiding the potential errors from the photodegradation of fluorescent probes, enzymolysis of DNA, or inactivation of

  11. 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.

  12. Bcl-2:Beclin 1 complex: multiple, mechanisms regulating autophagy/apoptosis toggle switch.

    PubMed

    Marquez, Rebecca T; Xu, Liang

    2012-01-01

    Cancer cells have developed novel mechanisms for evading chemotherapy-induced apoptosis and autophagy-associated cell death pathways. Upon the discovery that chemotherapeutics could target these cell death pathways in a manner that was not mutually exclusive, new discoveries about the interrelationship between these two pathways are emerging. Key proteins originally thought to be "autophagy-related proteins" are now found to be involved in either inducing or inhibiting apoptosis. Similarly, apoptosis inhibiting proteins can also block autophagy-associated cell death. One example is the complex formed by the autophagy protein, Beclin 1, and anti-apoptotic protein Bcl-2, which leads to inhibition of autophagy-associated cell death. Researchers have been investigating additional mechanisms that form/disrupt this complex in order to better design chemotherapeutics. This review will highlight the role Bcl-2 and Beclin 1 play in cancer development and drug resistance, as well as the role the Bcl-2:Beclin 1 complex in the switch between autophagy and apoptosis.

  13. Up regulation of Bax and down regulation of Bcl2 during 3-NC mediated apoptosis in human cancer cells.

    PubMed

    Naseri, Mohammad Hassan; Mahdavi, Majid; Davoodi, Jamshid; Tackallou, Saeed Hesami; Goudarzvand, Mahdi; Neishabouri, Shima Hallaj

    2015-01-01

    Recently, we have reported the induction of apoptosis by 2-amino-4-(3-nitrophenyl)-3-cyano-7-(dimethylamino)-4H-chromene (3-NC) in HepG2, T47D and HCT116 cells with low nano molar IC50 values. In this study, anti-proliferative effects of modified 4-aryle-4H-chromenes derivatives; 2-amino-4-(3-bromophenyl)-3-cyano-7-(dimethylamino)-4H-chromene (3-BC), 2-amino-4-(3-trifluoromethylphenyl)-3-cyano-7-(dimethylamino)-4H-chromene (3-TFC) and 2-amino-4-(4,5-methylenedioxyphenyl)-3-cyano-7-(dimethylamino)-4H-chromene (4, 5-MC) were investigated in three human cancer cell lines. Compared to 3-NC none of the compounds displayed better anti-proliferative effect, although 3-BC appeared somewhat similar. Therefore 3-NC was selected for further studies. Treatment of HepG2, T47D and HCT116 cells with this compound induced apoptosis as visualized by fluorescence microscopic study of Hoechst 33258 stained cells. Induction of apoptosis was quantified by Annexin V/PI staining using flow cytometry. Western blot analysis also revealed that 3-NC down-regulated the expression of anti-apoptotic protein Bcl2 and up-regulated pro-apoptotic protein Bax, in all of the cell lines. Nonetheless, HepG2 cell line was the most responsive to 3-NC as Bax and Bcl2 showed the most dramatic up and down regulation. Our previous finding that 3-NC down regulates Inhibitor of Apoptosis Proteins (IAPs) and the present observation that Bax is upregulated and Bcl2 is down regulated upon 3-NC treatment, this chromene derivative has the potential to overcome chemotherapy resistance caused by up regulation of these proteins.

  14. Quercetin inhibits human breast cancer cell proliferation and induces apoptosis via Bcl-2 and Bax regulation.

    PubMed

    Duo, Jian; Ying, Guo-Guang; Wang, Guo-Wen; Zhang, Li

    2012-06-01

    Breast cancer is a disease in which cancer cells form in the tissues of the breast. The present study aimed to explore the effect of the flavonoid compound quercetin on the growth and apoptosis of human breast cancer cells. Varying concentrations (12.5, 25, 50, 100, 200 µM) of quercetin were applied to cultured MCF-7 human breast cancer cells for defined lengths of time. At 50 to 200 µM doses, quercetin significantly inhibited the proliferation of MCF-7 cells assessed by MTT colorimetry, in both dose- and time-dependent manners (P<0.05). The compound also increased apoptosis after 48 h of exposure (P<0.05). Furthermore, following quercetin treatment Bcl-2 expression decreased significantly while Bax expression increased significantly (P<0.05). In brief, quercetin inhibits cell growth and induces apoptosis in MCF-7 human breast cancer cells. The mechanisms behind these effects may stem from the downregulation of Bcl-2 protein expression and upregulation of Bax expression.

  15. 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.

  16. 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.

  17. Quercetin induces apoptosis by activating caspase-3 and regulating Bcl-2 and cyclooxygenase-2 pathways in human HL-60 cells.

    PubMed

    Niu, Guomin; Yin, Songmei; Xie, Shuangfeng; Li, Yiqing; Nie, Danian; Ma, Liping; Wang, Xiuju; Wu, Yudan

    2011-01-01

    Quercetin is one of the naturally occurring dietary flavonol compounds. It is present abundantly in plants and has chemopreventive and anticancer effects. To investigate its anticancer mechanism, we examined the activity of quercetin against acute leukemia cell line, HL-60. Our results showed that quercetin inhibited cell proliferation and induced apoptosis in a time- and dose-dependent manner. Furthermore, quercetin down-regulated the expression of anti-apoptosis protein Bcl-2 and up-regulated the expression of pro-apoptosis protein Bax. Caspase-3 was also activated by quercetin, which started a caspase-3-depended mitochodrial pathway to induce apoptosis. It was also found that quercetin inhibited the expression of the cycloocygenase-2 (Cox-2) mRNA and Cox-2 protein. Taken together, these findings suggested that quercetin induces apoptosis in a caspase-3-dependent pathway by inhibiting Cox-2 expression and regulates the expression of downstream apoptotic components, including Bcl-2 and Bax. Quercetin can be a potent and promising medicine which might be safely used in leukemia therapy.

  18. 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.

  19. 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

  20. Transformer 2β and miR-204 regulate apoptosis through competitive binding to 3' UTR of BCL2 mRNA.

    PubMed

    Kuwano, Y; Nishida, K; Kajita, K; Satake, Y; Akaike, Y; Fujita, K; Kano, S; Masuda, K; Rokutan, K

    2015-05-01

    RNA-binding proteins and microRNAs are potent post-transcriptional regulators of gene expression. Human transformer 2β (Tra2β) is a serine/arginine-rich-like protein splicing factor and is now implicated to have wide-ranging roles in gene expression as an RNA-binding protein. RNA immunoprecipitation (RIP) with an anti-Tra2β antibody and microarray analysis identified a subset of Tra2β-associated mRNAs in HCT116 human colon cancer cells, many of which encoded cell death-related proteins including Bcl-2 (B-cell CLL/lymphoma 2). Tra2β knockdown in HCT116 cells decreased Bcl-2 expression and induced apoptosis. Tra2β knockdown accelerated the decay of BCL2α mRNA that encodes Bcl-2 and full-length 3' UTR, while it did not affect the stability of BCL2β mRNA having a short, alternatively spliced 3' UTR different from BCL2α 3' UTR. RIP assays with anti-Tra2β and anti-Argonaute 2 antibodies, respectively, showed that Tra2β bound to BCL2α 3' UTR, and that Tra2β knockdown facilitated association of miR-204 with BCL2α 3' UTR. The consensus sequence (GAA) for Tra2β-binding lies within the miR-204-binding site of BCL2 3' UTR. Mutation of the consensus sequence canceled the binding of Tra2β to BCL2 3' UTR without disrupting miR-204-binding to BCL2 3' UTR. Transfection of an anti-miR-204 or introduction of three-point mutations into the miR-204-binding site increased BCL2 mRNA and Bcl-2 protein levels. Inversely, transfection of precursor miR-204 reduced their levels. Experiments with Tra2β-silenced or overexpressed cells revealed that Tra2β antagonized the effects of miR-204 and upregulated Bcl-2 expression. Furthermore, TRA2β mRNA expression was significantly upregulated in 22 colon cancer tissues compared with paired normal tissues and positively correlated with BCL2 mRNA expression. Tra2β knockdown in human lung adenocarcinoma cells (A549) increased their sensitivity to anticancer drugs. Taken together, our findings suggest that Tra2β regulates apoptosis by

  1. Transformer 2β and miR-204 regulate apoptosis through competitive binding to 3′ UTR of BCL2 mRNA

    PubMed Central

    Kuwano, Y; Nishida, K; Kajita, K; Satake, Y; Akaike, Y; Fujita, K; Kano, S; Masuda, K; Rokutan, K

    2015-01-01

    RNA-binding proteins and microRNAs are potent post-transcriptional regulators of gene expression. Human transformer 2β (Tra2β) is a serine/arginine-rich-like protein splicing factor and is now implicated to have wide-ranging roles in gene expression as an RNA-binding protein. RNA immunoprecipitation (RIP) with an anti-Tra2β antibody and microarray analysis identified a subset of Tra2β-associated mRNAs in HCT116 human colon cancer cells, many of which encoded cell death-related proteins including Bcl-2 (B-cell CLL/lymphoma 2). Tra2β knockdown in HCT116 cells decreased Bcl-2 expression and induced apoptosis. Tra2β knockdown accelerated the decay of BCL2α mRNA that encodes Bcl-2 and full-length 3′ UTR, while it did not affect the stability of BCL2β mRNA having a short, alternatively spliced 3′ UTR different from BCL2α 3′ UTR. RIP assays with anti-Tra2β and anti-Argonaute 2 antibodies, respectively, showed that Tra2β bound to BCL2α 3′ UTR, and that Tra2β knockdown facilitated association of miR-204 with BCL2α 3′ UTR. The consensus sequence (GAA) for Tra2β-binding lies within the miR-204-binding site of BCL2 3′ UTR. Mutation of the consensus sequence canceled the binding of Tra2β to BCL2 3′ UTR without disrupting miR-204-binding to BCL2 3′ UTR. Transfection of an anti-miR-204 or introduction of three-point mutations into the miR-204-binding site increased BCL2 mRNA and Bcl-2 protein levels. Inversely, transfection of precursor miR-204 reduced their levels. Experiments with Tra2β-silenced or overexpressed cells revealed that Tra2β antagonized the effects of miR-204 and upregulated Bcl-2 expression. Furthermore, TRA2β mRNA expression was significantly upregulated in 22 colon cancer tissues compared with paired normal tissues and positively correlated with BCL2 mRNA expression. Tra2β knockdown in human lung adenocarcinoma cells (A549) increased their sensitivity to anticancer drugs. Taken together, our findings suggest that Tra2

  2. Pyrroloquinoline Quinone Induces Cancer Cell Apoptosis via Mitochondrial-Dependent Pathway and Down-Regulating Cellular Bcl-2 Protein Expression

    PubMed Central

    Min, Zhihui; Wang, Lingyan; Jin, Jianjun; Wang, Xiangdong; Zhu, Bijun; Chen, Hao; Cheng, Yunfeng

    2014-01-01

    Pyrroloquinoline quinone (PQQ) has been reported as a promising agent that might contribute to tumor cell apoptosis and death, yet little is known on its mechanisms. In current study, the effect of PQQ on cell proliferation and mitochondrial-dependent apoptosis were examined in 3 solid tumor cell lines (A549, Neuro-2A and HCC-LM3). PQQ treatment at low to medium dosage exhibited potent anti-tumor activity on A549 and Neuro-2A cells, while had comparably minimal impact on the viabilities of 2 human normal cell lines (HRPTEpiC and HUVEC). The apoptosis of the 3 tumor cell lines induced by PQQ were increased in a concentration-dependent manner, which might be attributed to the accumulation of intracellular reactive oxygen species (ROS), decline in ATP levels and dissipation of mitochondrial membrane potential (MMP), in conjunction with down-regulation of Bcl-2 protein expression, up-regulation of activated caspase-3, and disturbed phosphorylated MAPK protein levels. PQQ induced tumor cells apoptosis was significantly alleviated by pan-caspase inhibitor Z-VAD-FMK. The present work highlights the potential capability of PQQ as an anti-tumor agent with low toxicity towards normal cells through activating mitochondrial-dependent apoptosis pathways, and warrants its development for cancer therapy. PMID:25161699

  3. Expression of Apoptosis-regulating Proteins Bcl-2 and Bax in Lymph Node Aspirates from Dogs with Lymphoma.

    PubMed

    Meichner, K; Fogle, J E; English, L; Suter, S E

    2016-05-01

    Dysregulated apoptosis is a hallmark of tumorigenesis, and is also involved in resistance to cytotoxic treatment, and might be relevant in lymphoma in dogs. That Bcl-2/Bax expression patterns differ between lymphoma immunophenotypes, and that Bcl-2/Bax ratio is correlated with prognosis. Fifty-five client-owned dogs with multicentric lymphoma and 5 healthy dogs. Prospective, case-control study. We compared 3 methods (flow cytometry, qRT-PCR, Western blot) for Bcl-2 and Bax quantification in a subset of dogs. The effect of time on Bcl-2/Bax ratios measured by flow cytometry was assessed in lymphoma cell lines. Immunophenotype and Bcl-2/Bax expression by flow cytometry were determined in LN aspirates from all dogs with multicentric lymphoma compared to healthy dogs. Progression-free survival (PFS) was retrospectively evaluated in a group of dogs all receiving similar treatment. Bcl-2/Bax ratios remain consistent for at least 5 days after sample collection. Bcl-2/Bax ratio was higher in dogs with T-cell lymphoma (TCL; median 0.97, range 0.37-1.36) compared to B-cell lymphoma (BCL; median 0.36, range 0.07-1.45) (P < .0001) and normal dogs (median 0.36, range 0.21-0.48) (P = .0006), respectively. Dogs with Bcl-2/Bax ratios higher than the median of the group experienced a median PFS of 101 days and dogs with ratios equal and lower than the median had PFS of 130 days (P = .19). Higher intrinsic resistance to apoptosis following cytotoxic treatment might contribute to the less favorable prognosis associated with multicentric TCL in dogs. Whether Bcl-2/Bax will be helpful to identify canine BCL and TCL with more aggressive and more indolent behavior, respectively, should be evaluated in larger prospective clinical studies. Copyright © 2016 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.

  4. Sanguinarine-induced apoptosis: generation of ROS, down-regulation of Bcl-2, c-FLIP, and synergy with TRAIL.

    PubMed

    Kim, Shin; Lee, Tae-Jin; Leem, Jaechan; Choi, Kyeong Sook; Park, Jong-Wook; Kwon, Taeg Kyu

    2008-06-01

    Sanguinarine is a benzophenanthridine alkaloid derived from the root of Sanguinaria canadensis and other poppy-fumaria species, possessing potent antibacterial, antifungal, and anti-inflammatory activities. In this study, we investigated the underling mechanisms by which sanguinarine induce apoptosis in human breast cancer MDA-231 cells. Treatment of MDA-231 cells with sanguinarine induced remarkable apoptosis accompanying the generation of ROS. Consistently, sanguinarine-induced apoptosis was mediated by the increased reproductive cell death. Pretreatment with NAC or GSH attenuated sanguinarine-induced apoptosis, suggesting the involvement of ROS in this cell death. During sanguinarin-induced apoptosis, protein levels of pro-caspase-3, Bcl-2, cIAP2, XIAP, and c-FLIPs were reduced. Sanguinarine-mediated apoptosis was substantially blocked by ectopic expression of Bcl-2 and cFLIPs. Additionally, we found that sub-lethal doses of sanguinarine remarkably sensitized breast cancer cells to TRAIL-mediated apoptosis, but the cell death induced by sanguinarine and TRAIL in combination was not blocked by overexpression of Bcl-2 or Akt. Therefore, combinatory treatment of sanguinarine and TRAIL may overcome the resistance of breast cancer cells due to overexpression of Akt or Bcl-2.

  5. 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.

  6. Apoptosis through Bcl-2/Bax and Cleaved Caspase Up-Regulation in Melanoma Treated by Boron Neutron Capture Therapy

    PubMed Central

    Faião-Flores, Fernanda; Coelho, Paulo Rogério Pinto; Toledo Arruda-Neto, João Dias; Maria-Engler, Silvya Stuchi; Tiago, Manoela; Capelozzi, Vera Luiza; Giorgi, Ricardo Rodrigues; Maria, Durvanei Augusto

    2013-01-01

    Boron neutron capture therapy (BNCT) is a binary treatment involving selective accumulation of boron carriers in a tumor followed by irradiation with a thermal or epithermal neutron beam. The neutron capture reaction with a boron-10 nucleus yields high linear energy transfer (LET) particles, alpha and 7Li, with a range of 5 to 9 µm. These particles can only travel very short distances and release their damaging energy directly into the cells containing the boron compound. We aimed to evaluate proliferation, apoptosis and extracellular matrix (ECM) modifications of B16F10 melanoma and normal human melanocytes after BNCT. The amounts of soluble collagen and Hsp47, indicating collagen synthesis in the ECM, as well as the cellular markers of apoptosis, were investigated. BNCT decreased proliferation, altered the ECM by decreasing collagen synthesis and induced apoptosis by regulating Bcl-2/Bax in melanoma. Additionally, BNCT also increased the levels of TNF receptor and the cleaved caspases 3, 7, 8 and 9 in melanoma. These results suggest that multiple pathways related to cell death and cell cycle arrest are involved in the treatment of melanoma by BNCT. PMID:23527236

  7. Defective cell death signalling along the Bcl-2 regulated apoptosis pathway compromises Treg cell development and limits their functionality in mice.

    PubMed

    Tischner, Denise; Gaggl, Irene; Peschel, Ines; Kaufmann, Manuel; Tuzlak, Selma; Drach, Mathias; Thuille, Nikolaus; Villunger, Andreas; Jan Wiegers, G

    2012-02-01

    The Bcl-2 regulated apoptosis pathway is critical for the elimination of autoreactive lymphocytes, thereby precluding autoimmunity. T cells escaping this process can be kept in check by regulatory T (Treg) cells expressing the transcription and lineage commitment factor Foxp3. Despite the well-established role of Bcl-2 family proteins in shaping the immune system and their frequent deregulation in autoimmune pathologies, it is poorly understood how these proteins affect Treg cell development and function. Here we compared the relative expression of a panel of 40 apoptosis-associated genes in Treg vs. conventional CD4(+) T cells. Physiological significance of key-changes was validated using gene-modified mice lacking or overexpressing pro- or anti-apoptotic Bcl-2 family members. We define a key role for the Bim/Bcl-2 axis in Treg cell development, homeostasis and function but exclude a role for apoptosis induction in responder T cells as relevant suppression mechanism. Notably, only lack of the pro-apoptotic BH3-only protein Bim or Bcl-2 overexpression led to accumulation of Treg cells while loss of pro-apoptotic Bad, Bmf, Puma or Noxa had no effect. Remarkably, apoptosis resistant Treg cells showed reduced suppressive capacity in a model of T cell-driven colitis, posing a caveat for the use of such long-lived cells in possible therapeutic settings. Copyright © 2011 Elsevier Ltd. All rights reserved.

  8. Regulation of Calcium Fluxes and Apoptosis by BCL-2 Family Proteins in Prostate Cancer Cells

    DTIC Science & Technology

    2006-02-01

    cultured to 60% confluency in 10-cm dishes and treated with various concentrations of bortezomib or roscovitine for 24 hours. Cells were then harvested...not cdk inhibition was sufficient to promote TRAIL sensitization, we examined the effects of the broad-spectrum cdk inhibitor, roscovitine , on TRAIL...induced apoptosis. Roscovitine had no effect on apoptosis at the concentration and time point studied in the 253J B-V cells but did induce DNA

  9. Ferric nitrilotriacetate (Fe-NTA)-induced reactive oxidative species protects human hepatic stellate cells from apoptosis by regulating Bcl-2 family proteins and mitochondrial membrane potential

    PubMed Central

    Liu, Mei; Li, Shu-Jie; Xin, Yong-Ning; Ji, Shu-Sheng; Xie, Rui-Jin; Xuan, Shi-Ying

    2015-01-01

    Reactive oxidative species (ROS)-induced apoptosis of human hepatic stellate (HSC) is one of the treatments for liver fibrosis. However, how ROS (reactive oxygen species) affect HSC apoptosis and liver fibrosis is still unknown. In our study, ROS in human HSC cell line LX-2 was induced by ferric nitrilotriacetate (Fe-NTA) and assessed by superoxide dismutase (SOD) activity and methane dicarboxylic aldehyde (MDA) level. We found that in LX2 cells Fe-NTA induced notable ROS, which played a protective role in HSCs cells apoptosis by inhibiting Caspase-3 activation. Fe-NTA-induced ROS increased mRNA and protein level of anti-apoptosis Bcl-2 and decreased mRNA protein level of pro-apoptosis gene Bax, As a result, maintaining mitochondrial membrane potential of HSCs. Fe-NTA-induced ROS play a protective role in human HSCs by regulating Bcl-2 family proteins and mitochondrial membrane potential. PMID:26770403

  10. Acidosis Promotes Bcl-2 Family-mediated Evasion of Apoptosis

    PubMed Central

    Ryder, Christopher; McColl, Karen; Zhong, Fei; Distelhorst, Clark W.

    2012-01-01

    Acidosis arises in solid and lymphoid malignancies secondary to altered nutrient supply and utilization. Tumor acidosis correlates with therapeutic resistance, although the mechanism behind this effect is not fully understood. Here we show that incubation of lymphoma cell lines in acidic conditions (pH 6.5) blocks apoptosis induced by multiple cytotoxic metabolic stresses, including deprivation of glucose or glutamine and treatment with dexamethasone. We sought to examine the role of the Bcl-2 family of apoptosis regulators in this process. Interestingly, we found that acidic culture causes elevation of both Bcl-2 and Bcl-xL, while also attenuating glutamine starvation-induced elevation of p53-up-regulated modulator of apoptosis (PUMA) and Bim. We confirmed with knockdown studies that these shifts direct survival decisions during starvation and acidosis. Importantly, the promotion of a high anti- to pro-apoptotic Bcl-2 family member ratio by acidosis renders cells exquisitely sensitive to the Bcl-2/Bcl-xL antagonist ABT-737, suggesting that acidosis causes Bcl-2 family dependence. This dependence appears to be mediated, in part, by the acid-sensing G protein-coupled receptor, GPR65, via a MEK/ERK pathway. PMID:22685289

  11. Oleanolic acid from Prunella Vulgaris L. induces SPC-A-1 cell line apoptosis via regulation of Bax, Bad and Bcl-2 expression.

    PubMed

    Feng, Liang; Au-Yeung, Wai; Xu, You-Hua; Wang, Shan-Shan; Zhu, Quan; Xiang, Ping

    2011-01-01

    Prunella vulgaris L. (PV) has been used as a herb for chemoprevention of lung cancer. In this study, the main active compound, oleanolic acid (OA) was isolated from an ethanol extract and its chemical structure was identified according to the results of high performance liquid chromatography (HPLC), high performance thin layer chromatography (HPTLC) and liquid chromatography-mass spectrography (LC-MS). Results for cell viability indictated no notable differences between OA and ethanol extract of PV in lung adenocarcinoma SPC-A-1 cells measured by MTT assay. Consistent concentration-response curves. Fluorescence detection with acridine orange-ethidium bromide was used to evaluate apoptosis of SPC-A-1 cells. OA at 16 and 8 microM group increased significantly the apoptosis rate compared with normal and 1% DMSO groups (p<0.05). In addition, immunocytochemistry assays showed increase in Bax and Bad protein expression while Bcl-2 decreased. Moreover, the ratio of Bax/Bcl-2 was heightened by OA treatment. The results suggest OA induced apoptosis of lung adenocarcinoma cells through down-regulating Bcl-2 expression, and up-regulating Bax and Bad expression.

  12. 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

  13. Histone demethylase Jmjd3 regulates osteoblast apoptosis through targeting anti-apoptotic protein Bcl-2 and pro-apoptotic protein Bim.

    PubMed

    Yang, Di; Okamura, Hirohiko; Teramachi, Jumpei; Haneji, Tatsuji

    2016-04-01

    Posttranslational modifications including histone methylation regulate gene transcription through directly affecting the structure of chromatin. Trimethylation of histone H3K27 (H3K27me3) contributes to gene silencing and the histone demethylase Jumonji domain-containing 3 (Jmjd3) specifically removes the methylation of H3K27me3, followed by the activation of gene expression. In the present study, we explored the roles of Jmjd3 in regulating osteoblast apoptosis. Knockdown of Jmjd3 promoted osteoblast apoptosis induced by serum deprivation with decreased mitochondrial membrane potential and increased levels of caspase-3 activation, PARP cleavage, and DNA fragmentation. B cell lymphoma-2 (Bcl-2), an anti-apoptotic protein, was down-regulated by knockdown of Jmjd3 through retaining H3K27me3 on its promoter region. Knockdown of Jmjd3 increased the pro-apoptotic activity of Bim through inhibiting ERK-dependent phosphorylation of Bim. Protein kinase D1 (PKD1), which stimulates ERK phosphorylation, decreased in the Jmjd3-knockdown cells and introduction of PKD1 relieved osteoblast apoptosis in the Jmjd3-knockdown cells through increasing ERK-regulated Bim phosphorylation. These results suggest that Jmjd3 regulates osteoblast apoptosis through targeting Bcl-2 expression and Bim phosphorylation.

  14. Roscovitine-induced apoptosis in neutrophils and neutrophil progenitors is regulated by the Bcl-2-family members Bim, Puma, Noxa and Mcl-1.

    PubMed

    Gautam, Sanjivan; Kirschnek, Susanne; Wiesmeier, Michael; Vier, Juliane; Häcker, Georg

    2013-01-01

    Neutrophil granulocyte (neutrophil) apoptosis plays a key role in determining inflammation in infectious and non-infectious settings. Recent work has shown that inhibitors of cyclin-dependent kinases (cdk) such as roscovitine can potently induce neutrophil apoptosis and reduce inflammation. Using a conditional Hoxb8-expression system we tested the participation of Bcl-2-family proteins to roscovitine-induced apoptosis in mouse neutrophils and in neutrophil progenitor cells. Bcl-2 strongly protected against roscovitine-induced apoptosis in neutrophils. The isolated loss of either Bim or noxa provided significant, partial protection while protection through combined loss of Bim and noxa or Bim and Puma was only slightly greater than this individual loss. The only substantial change in protein levels observed was the loss of Mcl-1, which was not transcriptional and was inhibited by proteasome blockade. In progenitor cells there was no protection by the loss of Bim alone but substantial protection by the loss of both Bim and Puma; surprisingly, strongest protection was seen by the isolated loss of noxa. The pattern of protein expression and Mcl-1-regulation in progenitor cells was very similar to the one observed in differentiated neutrophils. In addition, roscovitine strongly inhibited proliferation in progenitor cells, associated with an accumulation of cells in G2/M-phase.

  15. Roscovitine-induced Apoptosis in Neutrophils and Neutrophil Progenitors Is Regulated by the Bcl-2-Family Members Bim, Puma, Noxa and Mcl-1

    PubMed Central

    Gautam, Sanjivan; Kirschnek, Susanne; Wiesmeier, Michael; Vier, Juliane; Häcker, Georg

    2013-01-01

    Neutrophil granulocyte (neutrophil) apoptosis plays a key role in determining inflammation in infectious and non-infectious settings. Recent work has shown that inhibitors of cyclin-dependent kinases (cdk) such as roscovitine can potently induce neutrophil apoptosis and reduce inflammation. Using a conditional Hoxb8-expression system we tested the participation of Bcl-2-family proteins to roscovitine-induced apoptosis in mouse neutrophils and in neutrophil progenitor cells. Bcl-2 strongly protected against roscovitine-induced apoptosis in neutrophils. The isolated loss of either Bim or noxa provided significant, partial protection while protection through combined loss of Bim and noxa or Bim and Puma was only slightly greater than this individual loss. The only substantial change in protein levels observed was the loss of Mcl-1, which was not transcriptional and was inhibited by proteasome blockade. In progenitor cells there was no protection by the loss of Bim alone but substantial protection by the loss of both Bim and Puma; surprisingly, strongest protection was seen by the isolated loss of noxa. The pattern of protein expression and Mcl-1-regulation in progenitor cells was very similar to the one observed in differentiated neutrophils. In addition, roscovitine strongly inhibited proliferation in progenitor cells, associated with an accumulation of cells in G2/M-phase. PMID:24223929

  16. Paeoniflorin inhibits nucleus pulposus cell apoptosis by regulating the expression of Bcl-2 family proteins and caspase-9 in a rabbit model of intervertebral disc degeneration

    PubMed Central

    SHI, LIJUN; TENG, HONGLIN; ZHU, MINYU; LI, CHI; HUANG, KELUN; CHEN, BI; DAI, YUSEN; WANG, JING

    2015-01-01

    Apoptosis plays a key role in the pathogenesis of internal disc disruption (IDD); therefore, the inhibition of apoptosis may offer a novel approach for treating IDD diseases. The aim of the present study was to investigate the effects and the underlying mechanisms of paeoniflorin through the detection of relevant indicators in a rabbit model of IDD. In total, 144 rabbits were used in the study and divided into four groups (n=36 per group). Rabbits successfully modeled with IDD received an intragastric injection of 120 mg/kg·day paeoniflorin (high-dose group), 30 mg/kg·day paeoniflorin (low-dose group) or saline (model saline group), while rabbits without IDD were used as a normal control group. The apoptosis rate of disc nucleus pulposus cells was detected using flow cytometry. In addition, the expression levels of Bcl-2, Bax and caspase-9 in the disc tissues were detected using immunohistochemistry and western blot analysis prior to and following the treatment. The results indicated that the expression levels of Bax in the low- and high-dose paeoniflorin groups were significantly reduced, while the Bcl-2 expression levels were significantly increased when compared with the model saline group (P<0.01). In addition, the expression levels of cleaved caspase-3 and cleaved caspase-9 were reduced in the low- and high-dose paeoniflorin groups, as compared with the model saline group (P<0.05). Furthermore, the average apoptotic index of the high- and low-dose paeoniflorin groups was decreased when compared with the model saline group (P<0.05). In conclusion, paeoniflorin was demonstrated to inhibit the apoptosis of nucleus pulposus cells and the activation of caspase-3 and caspase-9 through the regulation of Bcl-2 family protein expression. These results provide an experimental basis for the future treatment of IDD with paeoniflorin. PMID:26170945

  17. 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.

  18. Amygdalin induces apoptosis through regulation of Bax and Bcl-2 expressions in human DU145 and LNCaP prostate cancer cells.

    PubMed

    Chang, Hyun-Kyung; Shin, Mal-Soon; Yang, Hye-Young; Lee, Jin-Woo; Kim, Young-Sick; Lee, Myoung-Hwa; Kim, Jullia; Kim, Khae-Hawn; Kim, Chang-Ju

    2006-08-01

    Prostate cancer is one of the most common non-skin cancers in men. Amygdalin is one of the nitrilosides, natural cyanide-containing substances abundant in the seeds of plants of the prunasin family that have been used to treat cancers and relieve pain. In particular, D-amygdalin (D-mandelonitrile-beta-D-gentiobioside) is known to exhibit selective killing effect on cancer cells. Apoptosis, programmed cell death, is an important mechanism in cancer treatment. In the present study, we prepared the aqueous extract of the amygdalin from Armeniacae semen and investigated whether this extract induces apoptotic cell death in human DU145 and LNCaP prostate cancer cells. In the present results, DU145 and LNCaP cells treated with amygdalin exhibited several morphological characteristics of apoptosis. Treatment with amygdalin increased expression of Bax, a pro-apoptotic protein, decreased expression of Bcl-2, an anti-apoptotic protein, and increased caspase-3 enzyme activity in DU145 and LNCaP prostate cancer cells. Here, we have shown that amygdalin induces apoptotic cell death in human DU145 and LNCaP prostate cancer cells by caspase-3 activation through down-regulation of Bcl-2 and up-regulation of Bax. The present study reveals that amygdalin may offer a valuable option for the treatment of prostate cancers.

  19. [The effect of reactive oxygen species regulation of expression of Bcl-2 and Bax in apoptosis of human umbilical vein endothelial cell induced by heat stress].

    PubMed

    Li, Li; Gu, Zhengtao; Liu, Zhifeng; Su, Lei

    2014-07-01

    To observe the effect of heat stress-induced reactive oxygen species (ROS) burst on the regulation of expression of Bcl-2 and Bax in human umbilical vein endothelial cell (HUVEC) apoptosis induced by heat stress, and explore the pathogenesis of vascular endothelial damage caused by severe heat stroke. HUVEC heat stress model was reproduced. Cells of heat stress group were incubated at either 39, 41, or 43 centigrade for 2 hours, then all the cells were further incubated at 37 centigrade and 5% CO2 for 24 hours. Before heat stress, cells of 43 centigrade heat stress group were pretreated with 10 μmol/L MnTMPyP, which was a specific scavenger of ROS, for 1 hour. Cells of control group were incubated at 37 centigrade and 5% CO2. The amount of ROS was assayed with 2', 7'-dichlorofluorescin diacetate (DCFH-DA) and dihydroethidium (DHE) staining. Apoptosis was determined by using staining with Hoechst33258. The mRNA expressions of Bcl-2 and Bax were determined by reverse transcription-polymerase chain reaction (RT-PCR). The protein levels of Bcl-2, Bax, caspase-3 were analyzed by Western Blot. In addition, the effect of MnTMPyP on heat stress-induced apoptosis was also studied. Compared with control group, there was no obvious change in cells after 39 centigrade heat stress. With the increase in heat stress temperature up to 41 centigrade and 43 centigrade, viability of cells showed a lowering trend, with a burst of ROS, and an increase of mRNA and protein of Bax, and the protein of caspase-3 was significantly increased, the mRNA and protein of Bcl-2 were significantly decreased in a temperature-dependent manner. These changes were marked in 43 centigrade heat stress group as compared with those of the control group [cell viability: (46.00±4.00)% vs. (96.33±1.53)%, t=20.164, P=0.001; ROS (fluorescence relative value): 400.67±12.10 vs. 99.33±4.04, t=32.909, P=0.001; Bax mRNA (A value): 3.03±0.15 vs. 1.00±0.00, t=23.056, P=0.001; Bax protein (gray value): 3.97±0

  20. Sesamin suppresses STZ induced INS-1 cell apoptosis through inhibition of NF-κB activation and regulation of Bcl-2 family protein expression.

    PubMed

    Zheng, Shuguo; Zhao, Mengqiu; Ren, Younan; Wu, Yuanjie; Yang, Jieren

    2015-03-05

    Diverse risk factors for diabetes can induce oxidative stress, leading to pancreatic beta cell damage and insulin secretion dysfunction. In the present study, we evaluated the effect of sesamin on streptozotocin (STZ) induced apoptosis in INS-1 cells and the possible mechanisms implicated. After preincubation with indicated concentrations of sesamin (0.1, 1.0 and 10.0μmol/l) for 24h, INS-1 cells were exposed to STZ (3mmol/l) for 12h. Sesamin effectively improved STZ induced cell damage as determined by MTT [3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide] assay and insulin secretion capacity, and suppressed STZ induced cell apoptosis as evaluated by flow cytometry using annexin V and propidium iodide double staining. Western blot analysis demonstrated that sesamin markedly suppressed STZ induced nuclear factor kappa B (NF-κB) activation, with Bax protein down-regulated and Bcl-2 protein up-regulated significantly. Preincubation with sesamin resulted in an evident enhancement of total antioxidant capacity in INS-1 cells, accompanied by a significant reduction of intracellular reactive oxygen species and malondialdehyde, an end product of lipid peroxidation. Taken together, these findings suggested that sesamin was capable of suppressing STZ induced INS-1 cell apoptosis, which might be ascribed, at least partly, to the inhibition of NF-κB activation and subsequent regulation of Bcl-2 family protein expression. This study would provide a potential target for treatment of diabetes with sesamin as well as other antioxidants.

  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. RTKN2 Induces NF-KappaB Dependent Resistance to Intrinsic Apoptosis in HEK Cells and Regulates BCL-2 Genes in Human CD4+ Lymphocytes

    PubMed Central

    Collier, Fiona M; Loving, Andrea; Baker, Adele J; McLeod, Janet; Walder, Ken; Kirkland, Mark A

    2009-01-01

    The gene for Rhotekin 2 (RTKN2) was originally identified in a promyelocytic cell line resistant to oxysterol-induced apoptosis. It is differentially expressed in freshly isolated CD4+ T-cells compared with other hematopoietic cells and is down-regulated following activation of the T-cell receptor. However, very little is known about the function of RTKN2 other than its homology to Rho-GTPase effector, rhotekin, and the possibility that they may have similar roles. Here we show that stable expression of RTKN2 in HEK cells enhanced survival in response to intrinsic apoptotic agents; 25-hydroxy cholesterol and camptothecin, but not the extrinsic agent, TNFα. Inhibitors of NF-KappaB, but not MAPK, reversed the resistance and mitochondrial pro-apoptotic genes, Bax and Bim, were down regulated. In these cells, there was no evidence of RTKN2 binding to the GTPases, RhoA or Rac2. Consistent with the role of RTKN2 in HEK over-expressing cells, suppression of RTKN2 in primary human CD4+ T-cells reduced viability and increased sensitivity to 25-OHC. The expression of the pro-apoptotic genes, Bax and Bim were increased while BCL-2 was decreased. In both cell models RTKN2 played a role in the process of intrinsic apoptosis and this was dependent on either NF-KappaB signaling or expression of downstream BCL-2 genes. As RTKN2 is a highly expressed in CD4+ T-cells it may play a role as a key signaling switch for regulation of genes involved in T-cell survival. PMID:26124677

  3. Salvianolic acid B inhibits intermittent high glucose-induced INS-1 cell apoptosis through regulation of Bcl-2 proteins and mitochondrial membrane potential.

    PubMed

    Tao, Shanjun; Ren, Younan; Zheng, Haowen; Zhao, Mengqiu; Zhang, Xu; Zhu, Yuanmei; Yang, Jieren; Zheng, Shuguo

    2017-08-08

    Blood glucose fluctuations, also referred to as intermittent high glucose, have been validated to be more harmful than sustained high glucose in exacerbating pancreatic dysfunction by inducing β cell apoptosis. Salvianolic acid B (Sal B), an aqueous component of Salvia miltiorrhiza, has been proved beneficial to pancreatic islet function in diabetes, but the underlying mechanisms remain to be elucidated. The present study investigated the protective effect of Sal B on INS-1 cells exposed to intermittent high glucose and the possible mechanisms implicated. The results indicated that Sal B was able to restore cell viability and suppress INS-1 cell apoptosis induced by intermittent high glucose. Preincubation with Sal B led to a significant decrease of caspase-9 and caspase-3 activity and poly ADP-ribose polymerase (PARP) cleavage. Exposure to intermittent high glucose induced significant up-regulation of proapoptotic proteins, down-regulation of antiapoptotic protein and depolarization of mitochondrial membrane potential (MMP) in INS-1 cells, while these changes were reversed effectively in Sal B treated groups. In addition, Sal B markedly attenuated intermittent high glucose-induced oxidative stress as manifested by notably decreased levels of intracellular reactive oxygen species and malondialdehyde (MDA). Taken together, these results indicate that Sal B is able to suppress intermittent high glucose-induced INS-1 cell apoptosis, which might be ascribed to regulation of Bcl-2 family protein expression and preservation of mitochondrial membrane potential. Copyright © 2017. Published by Elsevier B.V.

  4. 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

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

    PubMed

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

    2004-05-01

    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.

  6. Mechanism of apoptosis induction by inhibition of the anti-apoptotic BCL-2 proteins.

    PubMed

    Chipuk, Jerry E; Fisher, John C; Dillon, Christopher P; Kriwacki, Richard W; Kuwana, Tomomi; Green, Douglas R

    2008-12-23

    Normal cellular lifespan is contingent upon preserving outer mitochondrial membrane (OMM) integrity, as permeabilization promotes apoptosis. BCL-2 family proteins control mitochondrial outer membrane permeabilization (MOMP) by regulating the activation of the pro-apoptotic BCL-2 effector molecules, BAX and BAK. Sustainable cellular stress induces proteins (e.g., BID, BIM, and cytosolic p53) capable of directly activating BAX and/or BAK, but these direct activators are sequestered by the anti-apoptotic BCL-2 proteins (e.g., BCL-2, BCL-xL, and MCL-1). In the event of accumulated or marked cellular stress, a coordinated effort between previously sequestered and nascent BH3-only proteins inhibits the anti-apoptotic BCL-2 repertoire to promote direct activator protein-mediated MOMP. We examined the effect of ABT-737, a BCL-2 antagonist, and PUMA, a BH3-only protein that inhibits the entire anti-apoptotic BCL-2 repertoire, with cells and mitochondria that sequestered direct activator proteins. ABT-737 and PUMA cooperated with sequestered direct activator proteins to promote MOMP and apoptosis, which in the absence of ABT-737 or PUMA did not influence OMM integrity or cellular survival. Our data show that the induction of apoptosis by inhibition of the anti-apoptotic BCL-2 repertoire requires "covert" levels of direct activators of BAX and BAK at the OMM.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

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

    PubMed Central

    Schoneich, 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 cell 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. PMID:24129924

  12. 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

  13. 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.

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. Sodium phenylacetate induces growth inhibition and Bcl-2 down-regulation and apoptosis in MCF7ras cells in vitro and in nude mice.

    PubMed

    Adam, L; Crépin, M; Savin, C; Israël, L

    1995-11-15

    Using a highly tumorigenic human breast cancer model (Ha-ras-transfected MCF7 cell line) we analyzed the efficacy of the differentiation-inducing agent sodium phenylacetate (NaPA), both in vitro and in vivo. NaPA-treated MCF7ras cells showed dose-dependent growth inhibition from 2.5 to 15 mM without apparent toxicity. Western blot analysis showed a Bcl-2 down-regulation after 48 h treatment with 5 mM NaPA, together with apparition of apoptotic nuclei by DAPI staining. Mice bearing MCF7ras xenografts (n = 40) were treated for 2 weeks through s.c.-delivering osmotic pumps, followed by 6 weeks of daily i.p. NaPA administration. After 3 weeks, the treated tumors showed growth arrest without regression for the whole observation time, e.g., 12 weeks. Immunohistochemical analysis showed Bcl-2 down-regulation and differentiation patterns: decrease of Ki-67 and increase of steroid receptors (estrogen and progesterone receptors) compared to controls. Cells cultured from treated tumors (II.b) displayed pseudotrabecular disposition as MCF7ras cells treated in vitro. They also showed a higher NaPA sensitivity, together with 70% Bcl-2 down-regulation as compared to the derived cells of untreated tumors (II.a). When reinjected into nude mice, II.b cells induced only one poorly vascularized, noninvasive tumor (8%) with lower proliferation index, 100% progesterone receptor positive cells, and 35% terminal deoxynucleotidyltransferase-mediated dUTP-X nick end labeling (+) nuclei, as compared to 100% induction of highly vascularized and invasive tumors with 3% terminal deoxynucleotidyltransferase-mediated dUTP-X nick end labeling (+) nuclei induced by II.a cells.

  19. Proliferative activity, apoptosis and expression of oestrogen receptor and Bcl-2 oncoprotein in canine mammary gland tumours.

    PubMed

    Yang, W-Y; Liu, C-H; Chang, C-J; Lee, C-C; Chang, K-J; Lin, C-T

    2006-01-01

    Samples of 39 canine mammary gland tumours (MGTs) were examined immunohistochemically for oestrogen receptor (ER-alpha), Bcl-2 protein and Ki67 antigen, and by TUNEL assay for apoptosis. ER-alpha was expressed by 80% (31/39) of the tumours, including all of the 15 benign tumours and 67% (16/42) of the malignant tumours. ER-alpha expression was greater in the benign than in the malignant tumours (P<0.01). Bcl-2 protein was detected in 62% (24/39) of the MGTs, of which 67% (10/15) were benign and 58% (14/24) malignant. No significant difference in Bcl-2 expression between benign and malignant tumours was detected. The Ki67 and TUNEL indices were greater in malignant than in benign tumours (P<0.01). Correlation analysis suggested that ER-alpha and Bcl-2 expression were related, but this observation lacked statistical significance. The levels of cell proliferation and apoptosis did not appear to be significantly correlated with the expression of Bcl-2. A positive relationship was apparent between cell proliferation and apoptosis, whilst a negative correlation between ER-alpha and cell proliferation was demonstrated. In conclusion, the suggestion of a positive correlation between ER-alpha and Bcl-2 in canine MGTs indicates that ER may be the regulator of Bcl-2 protein, as in human breast cancer. In contrast to cell proliferation and apoptosis, ER-alpha and Bcl-2 expression were greater in benign MGTs than in their malignant counterparts.

  20. 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.

  1. The CXCR4 inhibitor BL-8040 induces the apoptosis of AML blasts by down-regulating ERK BCL-2, MCL-1 and cyclin-D1 via altered miR-15a/16-1 expression.

    PubMed

    Abraham, M; Klein, S; Bulvik, B; Wald, H; Weiss, I D; Olam, D; Weiss, L; Beider, K; Eizenberg, O; Wald, O; Galun, E; Avigdor, A; Benjamini, O; Nagler, A; Pereg, Y; Tavor, S; Peled, A

    2017-03-10

    CXCR4 is a key player in the retention and survival of human acute myeloid leukemia (AML) blasts in the bone marrow (BM) microenvironment. We studied the effects of the CXCR4 antagonist BL-8040 on the survival of AML blasts and investigated the molecular mechanisms by which CXCR4 signaling inhibition leads to leukemic cell death. Treatment with BL-8040 induced the robust mobilization of AML blasts from the BM. In addition, AML cells exposed to BL-8040 underwent differentiation. Furthermore, BL-8040 induced the apoptosis of AML cells in vitro and in vivo. This apoptosis was mediated by the up-regulation of miR-15a/miR-16-1, resulting in down-regulation of the target genes BCL-2, MCL-1 and cyclin-D1. Overexpression of miR-15a/miR-16-1 directly induced leukemic cell death. BL-8040-induced apoptosis was also mediated by the inhibition of survival signals via the AKT/ERK pathways. Importantly, treatment with a BCL-2 inhibitor induced apoptosis and act together with BL-8040 to enhance cell death. BL-8040 also synergized with FLT3 inhibitors to induce AML cell death. Importantly, this combined treatment prolonged the survival of tumor-bearing mice and reduced minimal residual disease in vivo. Our results provide a rationale to test combination therapies employing BL-8040 and BCL2 or FLT3 inhibitors to achieve increased efficacy of these agents.Leukemia accepted article preview online, 10 March 2017. doi:10.1038/leu.2017.82.

  2. 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

  3. Lycopene Extracts from Different Tomato-Based Food Products Induce Apoptosis in Cultured Human Primary Prostate Cancer Cells and Regulate TP53, Bax and Bcl-2 Transcript Expression

    PubMed

    Soares, Nathalia da Costa Pereira; Machado, Clara Lima; Trindade, Bruno Boquimpani; Lima, Ingridy Celestino do Canto; Gimba, Etel Rodrigues Pereira; Teodoro, Anderson Junger; Takiya, Christina; Borojevic, Radovan

    2017-02-01

    Carotenoids are the main tomato components, especially lycopene. Lycopene is more bioavailable in tomato processed products than in raw tomatos, since formation of lycopene cis-isomers during food processing and storage may increase its biological activity. In the current study, we evaluated the influence of lycopene extracts (5 mg / mL) from different tomato-based food products (paste, sauce, extract and ketchup) on cell viability and apoptosis on primary human prostate cancer cells (PCa cels) for 96h. Using MTT assay, we observed a significant decrease on primary PCa cell viability upon treatment with lycopene extracted from either 4 tomato-based food products. Flow cytometeric analysis revealed that lycopene from tomato extract and tomato sauce promoted up to fifty-fold increase on the proportion of apoptotic cells, when compared to the control group. Using real time PCR assay, we found that lycopene promoted an upregulation of TP53 and Bax transcript expression and also downregulation of Bcl-2 expression in PCa cells. In conclusion, our data demostrate that cis-lycopene promoted a significant inhibition on primary PCa cell viability, as well as an increase on their apoptotic rates, evidencing that cis-lycopene contained in tomato sauce and extract cain mainly modulate of primary human prostate cancer cell survival.

  4. Lycopene Extracts from Different Tomato-Based Food Products Induce Apoptosis in Cultured Human Primary Prostate Cancer Cells and Regulate TP53, Bax and Bcl-2 Transcript Expression

    PubMed Central

    Soares, Nathalia da Costa Pereira; Machado, Clara Lima; Trindade, Bruno Boquimpani; Lima, Ingridy Celestino do Canto; Gimba, Etel Rodrigues Pereira; Teodoro, Anderson Junger; Takiya, Christina; Borojevic, Radovan

    2017-01-01

    Carotenoids are the main tomato components, especially lycopene. Lycopene is more bioavailable in tomato processed products than in raw tomatos, since formation of lycopene cis-isomers during food processing and storage may increase its biological activity. In the current study, we evaluated the influence of lycopene extracts (5 mg / mL) from different tomato-based food products (paste, sauce, extract and ketchup) on cell viability and apoptosis on primary human prostate cancer cells (PCa cels) for 96h. Using MTT assay, we observed a significant decrease on primary PCa cell viability upon treatment with lycopene extracted from either 4 tomato-based food products. Flow cytometeric analysis revealed that lycopene from tomato extract and tomato sauce promoted up to fifty-fold increase on the proportion of apoptotic cells, when compared to the control group. Using real time PCR assay, we found that lycopene promoted an upregulation of TP53 and Bax transcript expression and also downregulation of Bcl-2 expression in PCa cells. In conclusion, our data demostrate that cis-lycopene promoted a significant inhibition on primary PCa cell viability, as well as an increase on their apoptotic rates, evidencing that cis-lycopene contained in tomato sauce and extract cain mainly modulate of primary human prostate cancer cell survival. PMID:28345329

  5. 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.

  6. 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

  7. Silver nanoparticles biosynthesized using Achillea biebersteinii flower extract: apoptosis induction in MCF-7 cells via caspase activation and regulation of Bax and Bcl-2 gene expression.

    PubMed

    Baharara, Javad; Namvar, Farideh; Ramezani, Tayebe; Mousavi, Marzieh; Mohamad, Rosfarizan

    2015-02-05

    Silver nanoparticles (Ag-NPs), the most popular nanoparticles, possess unique properties. Achillea biebersteinii is a plant of the Asteraceae family rich in active antitumor components. The aim of this research was the characterization and investigation of the cytotoxic properties of Ag-NPs synthesized using A. biebersteinii flower extract, on a human breast cancer cell line. The Ag-NPs were synthesized after approximately 180 min of reaction at 40 °C, then they were characterized by UV-visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and dynamic light scattering (DLS). The anti-apoptosis effect of Ag-NPs on the MCF-7 cell line was investigated by MTT assay, DAPI and acridine orange staining and caspase activity. The transcriptional expression of bax, bcl-2, caspase-3, -8 and -9 were also evaluated by RT-PCR. The TEM images revealed that the Ag-NPs morphology had a different shape. The DLS indicated that the average hydrodynamic diameter of the biosynthesized Ag-NPs was around 12 nm. By UV-visible spectroscopy the strongest absorbance peak was observed at 460 nm. The FTIR results also showed interaction between the plant extract and Ag-NPs due to the similarity in the peak patterns. The EDS results showed that Ag-NPs display an absorption peak at 3 keV, indicating the presence of the element silver. The Ag-NPs caused a dose-dependent decrease in cell viability, fragmentation in nucleic acid, inhibited the proliferation and induction of apoptosis on MCF-7 by suppressing specific cell cycle genes, and simulation programmed cell dead genes. Further investigation is required to establish the potential of this novel and promising approach in cancer therapy.

  8. Copper Induces Apoptosis of Neuroblastoma Cells Via Post-translational Regulation of the Expression of Bcl-2-family Proteins and the tx Mouse is a Better Model of Hepatic than Brain Cu Toxicity.

    PubMed

    Chan, Hsien W; Liu, Tianbing; Verdile, Giuseppe; Bishop, Glenda; Haasl, Ryan J; Smith, Mark A; Perry, George; Martins, Ralph N; Atwood, Craig S

    2008-01-01

    The basic mechanism(s) by which altered Cu homeostasis is toxic to hepatocytes and neurons, the two major cell types affected in copper storage diseases such as Wilson's disease (WD), remain unclear. Using human M17 neuroblastoma cells as a model to examine Cu toxicity, we found that there was a time- and concentration-dependent induction of neuronal death, such that at 24 h there was a approximately 50 % reduction in viability with 25 muM Cu-glycine(2). Cu-glycine(2) (25:50 muM) treatment for 24 h significantly altered the expression of 296 genes, including 8 genes involved with apoptosis (BCL2-associated athanogene 3, BCL2/adenovirus E1B 19kDa interacting protein caspase 5, regulator of Fas-induced apoptosis, V-jun sarcoma virus 17 oncogene homolog, claudin 5, prostaglandin E receptor 3 and protein tyrosine phosphatase, non-receptor type 6). Surprisingly, changes in the expression of more 'traditional' apoptotic genes (Bcl-2, Bax, Bak and Bad) did not vary more than 20 %. To test whether the induction of apoptosis in neuroblastoma cells was via post-translational mechanisms, we measured the protein expression of these apoptotic markers in M17 neuroblastoma cells treated with Cu-glycine(2) (0-100 muM) for 24-48 h. Compared with glycine treated cells, Cu-glycine(2) reduced Bcl-2 expression by 50 %, but increased Bax and Bak expression by 130% and 400 %, respectively. To assess whether Cu also induced apoptotic cell death in a mouse model of WD, we measured the expression of these apoptotic markers in the liver and brain of mice expressing an ATP7b gene mutation (tx(J) mice) at 10 months of age (near the end of their lives when overt liver pathology is displayed). Changes in the liver expression of these apoptotic markers in tx(J) mice compared to background mice mirrored those of Cu treated neuroblastoma cells. In contrast, few changes in apoptotic protein expression were detected in the brain between tx(J) and background mice, indicating the tx(J) mouse is a good

  9. Copper Induces Apoptosis of Neuroblastoma Cells Via Post-translational Regulation of the Expression of Bcl-2-family Proteins and the txJ Mouse is a Better Model of Hepatic than Brain Cu Toxicity

    PubMed Central

    Chan, Hsien W.; Liu, Tianbing; Verdile, Giuseppe; Bishop, Glenda; Haasl, Ryan J.; Smith, Mark A.; Perry, George; Martins, Ralph N.; Atwood, Craig S.

    2008-01-01

    The basic mechanism(s) by which altered Cu homeostasis is toxic to hepatocytes and neurons, the two major cell types affected in copper storage diseases such as Wilson's disease (WD), remain unclear. Using human M17 neuroblastoma cells as a model to examine Cu toxicity, we found that there was a time- and concentration-dependent induction of neuronal death, such that at 24 h there was a ∼50 % reduction in viability with 25 μM Cu-glycine2. Cu-glycine2 (25:50 μM) treatment for 24 h significantly altered the expression of 296 genes, including 8 genes involved with apoptosis (BCL2-associated athanogene 3, BCL2/adenovirus E1B 19kDa interacting protein caspase 5, regulator of Fas-induced apoptosis, V-jun sarcoma virus 17 oncogene homolog, claudin 5, prostaglandin E receptor 3 and protein tyrosine phosphatase, non-receptor type 6). Surprisingly, changes in the expression of more ‘traditional’ apoptotic genes (Bcl-2, Bax, Bak and Bad) did not vary more than 20 %. To test whether the induction of apoptosis in neuroblastoma cells was via post-translational mechanisms, we measured the protein expression of these apoptotic markers in M17 neuroblastoma cells treated with Cu-glycine2 (0-100 μM) for 24-48 h. Compared with glycine treated cells, Cu-glycine2 reduced Bcl-2 expression by 50 %, but increased Bax and Bak expression by 130% and 400 %, respectively. To assess whether Cu also induced apoptotic cell death in a mouse model of WD, we measured the expression of these apoptotic markers in the liver and brain of mice expressing an ATP7b gene mutation (txJ mice) at 10 months of age (near the end of their lives when overt liver pathology is displayed). Changes in the liver expression of these apoptotic markers in txJ mice compared to background mice mirrored those of Cu treated neuroblastoma cells. In contrast, few changes in apoptotic protein expression were detected in the brain between txJ and background mice, indicating the txJ mouse is a good model of hepatic, but

  10. 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

  11. VIP Down-regulates the Inflammatory Potential and Promotes Survival of Dying (Neural Crest-derived) Corneal Endothelial Cells ex vivo: Necrosis to Apoptosis Switch and Up-regulation of Bcl-2 and N-cadherin

    PubMed Central

    Koh, Shay-Whey M.; Cheng, Jason; Dodson, Rebecca M.; Ku, Chao-Yar T; Abbondandolo, Cara J.

    2009-01-01

    The neuropeptide VIP is anti-inflammatory and protective in the immune and nervous systems, respectively. The present study demonstrated in corneal endothelial (CE) cells injured by severe oxidative stress (1.4mM H2O2) in bovine corneal organ cultures that VIP pre-treatment (0, 10−10, 10−8, and 10−6 M; 15 min), in a VIP concentration-dependent manner, switched the inflammation-causing necrosis to inflammation neutral apoptosis (showing annexin V-binding, chromatin condensation, and DNA fragmentation) and upheld ATP levels in a VIP antagonist (SN)VIPhyb-sensitive manner, while up-regulated mRNA levels of the anti-apoptotic Bcl-2 and the differentiation marker N-cadherin in a kinase A inhibitor-sensitive manner. As a result, VIP, in a concentration-dependent and VIP antagonist-sensitive manners, promoted long-term CE cell survival. ATP levels, a determining factor in the choice of apoptosis vs necrosis, measured after VIP pre-treatment and 0.5 min post- H2O2 were 39.6±3.3, 50.8±6.2, 60.1±4.8, and 53.6±5.3 pmoles/μg protein (mean±sem), respectively (p<0.05, ANOVA). VIP treatment alone concentration-dependently increased levels of N-cadherin (Koh et al., 2008), the phosphorylated cAMP-responsive-element binding protein and Bcl-2, while10−8 M VIP, in a VIP antagonist (SN)VIPhyb-sensitive manner, increased ATP level by 38% (p< 0.02) and decreased glycogen level by 32% (p< 0.02). VPAC1 (not VPAC2) receptor was expressed in CE cells. Thus, CE cell VIP/VPAC1 signaling is both anti-inflammatory and protective in the corneal endothelium. PMID:19250342

  12. Failure of stress-induced downregulation of Bcl-2 contributes to apoptosis resistance in senescent human diploid fibroblasts.

    PubMed

    Ryu, S J; Oh, Y S; Park, S C

    2007-05-01

    We previously reported that senescent human diploid fibroblasts (HDFs) are resistant to apoptosis induced by H(2)O(2) and staurosporine. We report here that senescent HDFs are resistant to thapsigargin-induced apoptosis as well. These agonists caused the reductions in mitochondrial membrane potential (MMP) and in the apoptosis inhibitory protein (B-cell lymphoma) only in young HDFs but not in senescent HDFs. In addition, downregulation of Bcl-2 increased the sensitivity of senescent HDFs to apoptosis induction, suggesting the significant role of Bcl-2 in apoptosis resistance of the senescent HDFs. We further found that P-cAMP response element-binding protein (CREB), a positive regulator of Bcl-2, decreased in stress-induced apoptosis of young HDFs but not in senescent HDFs, and that Bcl-2 was markedly reduced in CREB small interfering RNA (siRNA), transfected senescent HDFs. In addition, activity of protein phosphatase 2A (PP2A), which dephosphorylates p-CREB, significantly increased in young HDFs but not in senescent HDFs treated with H(2)O(2), staurosporine or thapsigargin. Taken together, these results suggest that failure of stress-induced downregulation of Bcl-2 underlies resistance of senescent HDFs to apoptosis.

  13. 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.

  14. Upregulation of Bax and Bcl-2 following prenatal cocaine exposure induces apoptosis in fetal rat brain.

    PubMed

    Xiao, DaLiao; Zhang, Lubo

    2008-01-01

    Cocaine abuse during pregnancy has been associated with numerous adverse perinatal outcomes. The present study was to determine whether prenatal cocaine exposure induced apoptosis and the possible role of Bcl-2 family genes in the programming cell death in fetal rat brain. Pregnant rats were treated with cocaine subcutaneously (30 & 60 mg/kg/day) from day 15 to 21 of gestation. Then the fetal and maternal brains were isolated. Cocaine produced a dose-dependent decrease in fetal brain weight and brain/body weight ratio (P<0.05). Apoptotic nuclei in fetal brain were increased from 2.6 +/- 0.1 (control) to 8.1+/- 0.6 (low dose) and 10.4 +/- 0.2% (high dose) (P<0.05). In accordance, cocaine dose dependently increased activities of caspase-3, caspase-8, and caspase-9 (% of control) in the fetal brain by 177%, 155%, 174%, respectively, at 30 mg/kg/day, and by 191%, 176%, 274%, respectively, at 60 mg/kg/day. In contrast, cocaine showed no effect on caspase activities in the maternal brain. Cocaine produced a dose-dependent increase in both Bcl-2 and Bax protein expression in the fetal brain, and increased the ratio of Bax/Bcl-2 at dose of 30 mg/kg/day (P<0.05). Our study has demonstrated that prenatal cocaine exposure induces apoptosis in the fetal brain, and suggested that up-regulating Bax/Bcl-2 gene expression may be involved in cocaine-induced apoptosis. The increased apoptosis of neuronal cells in the fetal brain is likely to play a key role in cocaine-induced neuronal defects during fetal development.

  15. 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.

  16. 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.

  17. Carnosic acid sensitized TRAIL-mediated apoptosis through down-regulation of c-FLIP and Bcl-2 expression at the post translational levels and CHOP-dependent up-regulation of DR5, Bim, and PUMA expression in human carcinoma caki cells

    PubMed Central

    Bae, Jae Hoon; Kwon, Taeg Kyu

    2015-01-01

    Carnosic acid is a phenolic diterpene from rosmarinus officinalis, and has multiple functions, such as anti-inflammatory, anti-viral, and anti-tumor activity. In this study, we examined whether carnosic acid could sensitize TRAIL-mediated apoptosis in human renal carcinoma Caki cells. We found that carnosic acid markedly induced TRAIL-mediated apoptosis in human renal carcinoma (Caki, ACHN, and A498), and human hepatocellular carcinoma (SK-HEP-1), and human breast carcinoma (MDA-MB-231) cells, but not normal cells (TMCK-1 and HSF). Carnosic acid induced down-regulation of c-FLIP and Bcl-2 expression at the post-translational levels, and the over-expression of c-FLIP and Bcl-2 markedly blocked carnosic acid-induced TRAIL sensitization. Furthermore, carnosic acid induced death receptor (DR)5, Bcl-2 interacting mediator of cell death (Bim), and p53 up-regulated modulator of apoptosis (PUMA) expression at the transcriptional levels via CCAAT/enhancer-binding protein-homologous protein (CHOP). Down-regulation of CHOP expression by siRNA inhibited DR5, Bim, and PUMA expression, and attenuated carnosic acid plus TRAIL-induced apoptosis. Taken together, our study demonstrates that carnosic acid enhances sensitization against TRAIL-mediated apoptosis through the down-regulation of c-FLIP and Bcl-2 expression, and up-regulation of ER stress-mediated DR5, Bim, and PUMA expression at the transcriptional levels. PMID:25596735

  18. Tumor growth inhibition, apoptosis, and Bcl-2 down-regulation of MCF-7ras tumors by sodium phenylacetate and tamoxifen combination.

    PubMed

    Adam, L; Crépin, M; Isräel, L

    1997-03-15

    We demonstrated previously the antitumoral and antiproliferative effects of sodium phenylacetate (NaPA) on malignant breast epithelial MCF-7ras cells and its lack of toxicity. The present in vivo protocols were as follows: (1) a control group; (2) a NaPA-receiving group (450 mg/kg) through s.c. osmotic pumps (ALZA Corp.) for 2 weeks, followed by 2 weeks with no treatment; and (3) a tamoxifen (TAM)-receiving group (20 mg/kg two times per week). The second group was further divided as follows: (a) a group receiving same doses of NaPA; (b) a TAM-receiving group; and (c) a group receiving both NaPA and TAM. Although tumors treated by TAM alone (group 3) showed progressive regrowth after 6 weeks, indicating an escape from antiestrogen inhibition, the TAM-administered group, following 2 weeks of NaPA pretreatment (group 2b), showed significant tumor regression of about 40% after 8 weeks. This effect was amplified to over 60% (P < 0.001) by simultaneous administration of the two drugs (group 2c). The last group displayed about 30% apoptotic-like nuclei, together with lower proliferation index, and less tumor vascularization, as compared to less than 5% terminal deoxytransferase-mediated dUTP-X nick end labeling-positive nuclei, highly vascularized tumors, in the TAM-treated group. Furthermore, in vitro administration of 4-OH-tamoxifen induced a Bcl-2 up-regulation in MCF-7ras cells, which was completely abolished by NaPA pretreatment. The combination of NaPA and OHT induced significant cell differentiation with cell cycle accumulation in the G0-G1 phase.

  19. Developmental regulation of the Bcl-2 protein and susceptibility to cell death in B lymphocytes.

    PubMed Central

    Merino, R; Ding, L; Veis, D J; Korsmeyer, S J; Nuñez, G

    1994-01-01

    Cell death is a prominent feature of B cell development. For example, a large population of B cells dies at the pre-B cell stage presumably due to the failure to express a functional immunoglobulin receptor. In addition, developing B cells expressing antigen receptors for self are selectively eliminated at the immature B cell stage. The molecular signals that control B cell survival are largely unknown. The product of the bcl-2 proto-oncogene may be involved as its overexpression inhibits apoptotic cell death in a variety of biological systems. However, the physiological role of the endogenous Bcl-2 protein during B cell development is undetermined. Here we show a striking developmental regulation of the Bcl-2 protein in B lymphocytes. Bcl-2 is highly expressed in CD43+ B cell precursors (pro-B cells) and mature B cells but downregulated at the pre-B and immature B cell stages of development. We found that Bcl-2 expressed by B cells is a long-lived protein with a half-life of approximately 10 h. Importantly, susceptibility to apoptosis mediated by the glucocorticoid hormone dexamethasone is stage-dependent in developing B cells and correlates with the levels of Bcl-2 protein. Furthermore, expression of a bcl-2 transgene rescued pre-B and immature B cells from dexamethasone-induced cell death, indicating that Bcl-2 can inhibit the apoptotic cell death of progenitors and early B cells. Taken together, these findings argue that Bcl-2 is a physiological signal controlling cell death during B cell development. Images PMID:8313913

  20. CXCR4 Chemokine Receptor Signaling Induces Apoptosis in Acute Myeloid Leukemia Cells via Regulation of the Bcl-2 Family Members Bcl-XL, Noxa, and Bak*

    PubMed Central

    Kremer, Kimberly N.; Peterson, Kevin L.; Schneider, Paula A.; Meng, X. Wei; Dai, Haiming; Hess, Allan D.; Smith, B. Douglas; Rodriguez-Ramirez, Christie; Karp, Judith E.; Kaufmann, Scott H.; Hedin, Karen E.

    2013-01-01

    The CXCR4 chemokine receptor promotes survival of many different cell types. Here, we describe a previously unsuspected role for CXCR4 as a potent inducer of apoptosis in acute myeloid leukemia (AML) cell lines and a subset of clinical AML samples. We show that SDF-1, the sole ligand for CXCR4, induces the expected migration and ERK activation in the KG1a AML cell line transiently overexpressing CXCR4, but ERK activation did not lead to survival. Instead, SDF-1 treatment led via a CXCR4-dependent mechanism to apoptosis, as evidenced by increased annexin V staining, condensation of chromatin, and cleavage of both procaspase-3 and PARP. This SDF-1-induced death pathway was partially inhibited by hypoxia, which is often found in the bone marrow of AML patients. SDF-1-induced apoptosis was inhibited by dominant negative procaspase-9 but not by inhibition of caspase-8 activation, implicating the intrinsic apoptotic pathway. Further analysis showed that this pathway was activated by multiple mechanisms, including up-regulation of Bak at the level of mRNA and protein, stabilization of the Bak activator Noxa, and down-regulation of antiapoptotic Bcl-XL. Furthermore, adjusting expression levels of Bak, Bcl-XL, or Noxa individually altered the level of apoptosis in AML cells, suggesting that the combined modulation of these family members by SDF-1 coordinates their interplay to produce apoptosis. Thus, rather than mediating survival, SDF-1 may be a means to induce apoptosis of CXCR4-expressing AML cells directly in the SDF-1-rich bone marrow microenvironment if the survival cues of the bone marrow are disrupted. PMID:23798675

  1. 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.

  2. [Role of BCL-2, caspase-3 and NF-κB in astragaloside inducing apoptosis of human NB4 cells].

    PubMed

    Ni, Jing; Xie, Xi; Xie, Jing; Hu, Xue-Ying; Huang, Zhen-Qi; Xia, Rui-Xiang

    2014-06-01

    This study was purposed to investigate the apoptosis-inducing effect of astragalosides on acute promyelocytic leukemia(APL) cell line NB4 and its mechanism. NB4 cells were treated with different concentrations (200, 300, 400 µg /ml) of astragalosides for 48 h. The cell proliferation was assayed by using CCK-8 method; the cell apoptosis was analyzed by flow cytometry with Annexin V-FITE/PI double staining. The mRNA expression of BCL-2 and the relative activity of BCL-2, NF-κB and caspase-3 were detected by RT-PCR and Western blot, respectively. The results showed that after treated with astragalosides for 48 h, astragalosides inhibited NB4 cell proliferation in concentration-dependent way, the apoptosis rate of NB4 cells gradually elevated from 4.69% to 40.85% with the increasing of astragalosides concentration. Simultaneously, the mRNA expression of BCL-2 was down-regulated, Western blot analysis showed that the protein expression levels of BCL-2 and NF-κB decreased after astragalosides treatment, while caspase-3 protein expression level increased. It is concluded that the molecular mechanism of the astragalosides-induced apoptosis in NB4 cells may be associated with down-regulation of the expression of BCL-2 and NF-κB, finally the relative activity of caspase-3 activated.

  3. 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.

  4. Induction of bcl-2 expression by phosphorylated CREB proteins during B-cell activation and rescue from apoptosis.

    PubMed Central

    Wilson, B E; Mochon, E; Boxer, L M

    1996-01-01

    Engagement of surface immunoglobulin on mature B cells leads to rescue from apoptosis and to proliferation. Levels of bcl-2 mRNA and protein increase with cross-linking of surface immunoglobulin. We have located the major positive regulatory region for control of bcl-2 expression in B cells in the 5'-flanking region. The positive region can be divided into an upstream and a downstream regulatory region. The downstream regulatory region contains a cyclic AMP-responsive element (CRE). We show by antibody supershift experiments and UV cross-linking followed by denaturing polyacrylamide gel electrophoresis that both CREB and ATF family members bind to this region in vitro. Mutations of the CRE site that result in loss of CREB binding also lead to loss of functional activity of the bcl-2 promoter in transient-transfection assays. The presence of an active CRE site in the bcl-2 promoter implies that the regulation of bcl-2 expression is linked to a signal transduction pathway in B cells. Treatment of the mature B-cell line BAL-17 with either anti-immunoglobulin M or phorbol 12-myristate 13-acetate leads to an increase in bcl-2 expression that is mediated by the CRE site. Treatment of the more immature B-cell line, Ramos, with phorbol esters rescues the cells from calcium-dependent apoptosis. bcl-2 expression is increased following phorbol ester treatment, and the increased expression is dependent on the CRE site. These stimuli result in phosphorylation of CREB at serine 133. The phosphorylation of CREB that results in activation is mediated by protein kinase C rather than by protein kinase A. Although the CRE site is necessary, optimal induction of bcl-2 expression requires participation of the upstream regulatory element, suggesting that phosphorylation of CREB alters its interaction with the upstream regulatory element. The CRE site in the bcl-2 promoter appears to play a major role in the induction of bcl-2 expression during the activation of mature B cells and during

  5. 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.

  6. 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.

  7. Sulforaphene promotes Bax/Bcl2, MAPK-dependent human gastric cancer AGS cells apoptosis and inhibits migration via EGFR, p-ERK1/2 down-regulation.

    PubMed

    Mondal, Arindam; Biswas, Raktim; Rhee, Yun-Hee; Kim, Jongkee; Ahn, Jin-Chul

    2016-01-01

    Gastric cancer migration and invasion considered as main causes of this cancer-related death around the world. Sulforaphene (4-isothiocyanato-4R-(methylsulfinyl)-1-butene), a structural analog of sulforaphane, has been found to exhibit anticancer potential against different cancers. Our aim was to investigate whether dietary isothiocyanate sulforaphene (SFE) can promote human gastric cancer (AGS) cells apoptosis and inhibit migration. Cells were treated with various concentrations of SFE and cell viability, morphology, intracellular ROS, migration and different signaling protein expressions were investigated. The results indicate that SFE decreases AGS cell viability and induces apoptosis in a dose-dependent manner. Intracellular ROS generation, dose- and time-dependent Bax/Bcl2 alteration and signaling proteins like cytochrome c, Casp-3, Casp-8 and PARP-1 higher expression demonstrated the SFE-induced apoptotic pathway in AGS cells. Again, SFE induced apoptosis also accompanied by the phosphorylation of mitogen-activated protein kinases (MAPKs) like JNK and P-38. Moreover, dose-dependent EGFR, p-ERK1/2 down-regulation and cell migration inhibition at non-toxic concentration confirms SFE activity in AGS cell migration inhibition. Thus, this study demonstrated effective chemotherapeutic potential of SFE by inducing apoptisis as well as inhibiting migration and their preliminary mechanism for human gastric cancer management.

  8. Interleukin-2 receptor common gamma-chain signaling cytokines regulate activated T cell apoptosis in response to growth factor withdrawal: selective induction of anti-apoptotic (bcl-2, bcl-xL) but not pro-apoptotic (bax, bcl-xS) gene expression.

    PubMed

    Akbar, A N; Borthwick, N J; Wickremasinghe, R G; Panayoitidis, P; Pilling, D; Bofill, M; Krajewski, S; Reed, J C; Salmon, M

    1996-02-01

    Cytokine deprivation from activated T cells leads to apoptosis associated with down-regulation of the bcl-2 gene product. It is not clear, however, how cytokines other than interleukin-2 (IL-2) may affect this process and regulate the involvement of other apoptosis-modulating genes. We show that a group of cytokines including IL-2 (IL-2R gamma), prevent the apoptosis of IL-2-deprived activated T cells. This rescue involves the induction of the anti-apoptosis genes bcl-2 and bcl-xL), but causes little change in expression of bax and bcl-xS, which promote apoptosis. Furthermore, the prevention of apoptosis and induction of proliferation by the common gamma chain cytokines can be dissociated. Thus, when proliferation is blocked, the common gamma chain cytokines still induce up-regulation of bcl-2 relative to bax and retard apoptosis. These cytokines can thus regulate the persistence or removal of effector T cells by coordinating the balance between genes which promote and those which inhibit apoptosis, events which are probably mediated at least in part by signals through the common gamma chain. These data also implicate inappropriate T cell apoptosis resulting from a dysfunctional common gamma-chain as part of the pathophysiological defect in patients with X-linked severe-combined immunodeficiency (SCID).

  9. 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.

  10. Allicin induces apoptosis in EL-4 cells in vitro by activation of expression of caspase-3 and -12 and up-regulation of the ratio of Bax/Bcl-2.

    PubMed

    Wang, Ziren; Liu, Zhonghu; Cao, Zhiheng; Li, Lan

    2012-01-01

    Garlic (Allium sativum L.; Liliaceae) has been widely demonstrated in the role of cancer prevention, but the specific compound in garlic corresponding to this effect and its mechanisms are not clearly known. Allicin is one of the organic sulphur compounds derived from garlic. In the present study we investigated the anti-proliferative and pro-apoptotic activities of allicin in murine T-lymphocytes (EL-4) and the mechanism of inducing apoptosis in vitro. The results showed that allicin was effective in inhibiting the proliferation of EL-4 cells in vitro in a concentration-dependent manner. Further, allicin could induce the formation of apoptotic bodies, nuclear condensation, DNA spallation, and even activated the expression of caspase-3, -12 and cytochrome C (cyt C). Finally, allicin up-regulated the ratio of Bax/Bcl-2 and induced a mitochondrion membrane potential (MMP) decrease. Allicin induced apoptosis in EL-4 cells in a time- and concentration-dependent manner, in which the mitochondrial pathway might play a central role.

  11. Methioninase gene therapy with selenomethionine induces apoptosis in bcl-2-overproducing lung cancer cells.

    PubMed

    Yamamoto, Norio; Gupta, Anshu; Xu, Mingxu; Miki, Kenji; Tsujimoto, Yoshihide; Tsuchiya, Hiroyuki; Tomita, Katsuro; Moossa, A R; Hoffman, R M

    2003-06-01

    We have previously shown that the toxic pro-oxidant methylselenol is released from selenomethionine (SeMET) by cancer cells transformed with the adenoviral methionine alpha,gamma-lyase (methioninase, MET) gene cloned from Pseudomonas putida. Methylselenol damaged the mitochondria via oxidative stress, and caused cytochrome c release into the cytosol thereby activating caspase enzymes and thereby apoptosis. However, gene therapy strategies are less effective if tumor cells overexpress the antiapoptotic mitochondrial protein bcl-2. In this study, we investigated whether rAdMET/SeMET was effective against bcl-2-overproducing A549 lung cancer cells. We established two clones of the human lung cancer A549 cell line that show moderate and high expression levels of bcl-2, respectively, compared to the parent cell line, which has very low bcl-2 expression. Staurosporine-induced apoptosis was inhibited in the bcl-2-overproducing clones as well as in the parental cell line. In contrast to staurosporine, apoptosis was induced in the bcl-2-overproducing clones as well as the parental cell line by AdMET/SeMET. Apoptosis in the rAdMET-SeMET-treated cells was determined by fragmentation of nuclei, and release of cytochrome c from mitochondria to the cytosol. A strong bystander effect of AdMET/SeMET was observed on A549 cells as well as the bcl-2-overproducing clones. rAdMET/SeMET prodrug gene therapy is therefore a promising novel strategy effective against bcl-2 overexpression, which has blocked other gene therapy strategies.

  12. Differential sensitivity of skeletal and fusimotor neurons to Bcl-2-mediated apoptosis during neuromuscular development.

    PubMed

    Hui, K; Kucera, J; Henderson, J T

    2008-04-01

    Proper development of the nervous system requires that a carefully controlled balance be maintained between both proliferation and neuronal survival. The process of programmed cell death is believed to play a key role in regulating levels of neuronal survival, in large part through the action of antiapoptotic proteins, such as Bcl-2. Consistent with this, Bcl-2 has been shown to be a key regulator of apoptotic signaling in post-mitotic neurons. However, we still know remarkably little regarding the role that Bcl-2 plays in regulating the survival of specific motor neuron populations. In the present study, we have examined somatic motor neurons of the lumbar spinal cord, and branchiomotor neurons of the facial nucleus in bcl-2-null mice to determine the differential dependence among motor neuron populations with respect to Bcl-2-mediated survival. Examination of neuronal and axon number, axonal area, and the distribution of axonal loss in bcl-2-null mice demonstrates that, in contrast to the great majority of alpha motor neurons, gamma motor neurons exhibit a unique dependence upon bcl-2 for survival. These results demonstrate, for the first time, the connection between Bcl-2 expression, motor neuron survival, and the establishment of different motor populations.

  13. [Effects of blueberry on apoptosis and expression of Bcl-2 and Bax in HSC-T6].

    PubMed

    Lu, Shuang; Cheng, Mingliang; Yang, Demeng; Liu, Yang; Guan, Li; Wu, Jun

    2015-08-18

    To investigate the effects of blueberry on the apoptosis, expression of Bcl-2 and Bax in rat hepatic stellate cell (HSC-T6). 10% blueberry serum at low, middle and high dose, 10% Fu-Fang-Bie-Jia-Ruan-Gan tablet serum and 10% saline serum were prepared by method of serum pharmacology. Subcultured HSC-T6 was divided into saline serum control group, blueberry serum at low, middle, high dose and Fu-Fang-Bie-Jia-Ruan-Gan tablet serum group, and then was respectively incubated at different dose of 10% blueberry serum, 10% Fu-Fang-Bie-Jia-Ruan-Gan tablet serum and 10% saline serum for 72 hours.Apoptosis of HSC-T6 was detected using flow cytometry with annexin V FITC/PI double staining. The expression of Bcl-2 and Bax in HSC-T6 were examined using immunocytochemistry and Western blotting, respectively. There was no significant difference for HSC-T6 Bax protein expression in the low, middle and high dose blueberry serum groups, compared with saline serum control group, respectively.In the high-dose blueberry serum group HSC-T6 early and total apoptosis rate increased significantly compared with the saline serum control group (5.55% ± 0.98% vs 2.53% ± 0.46%, 7.01% ± 1.05% vs 2.96% ± 0.81%, both P<0.05); Bcl-2 protein expression was significantly decreased (A value, 82 ± 35 vs 51 ± 13, P<0.05); Bcl-2/Bax ratio was significantly decreased (0.26 ± 0.02 vs 0.46 ± 0.03, P<0.05); HSC-T6 early and total apoptosis rate, Bcl-2 expression and Bcl-2/Bax ratio in the low and the middle dose blueberry serum group showed no significant difference with the saline serum control group. Blueberry can induce HSC-T6 apoptosis by down-regulating Bcl-2 expression and decreasing the ratio of Bcl-2/Bax in HSC-T6 cells, so it may have potential interference effects on hepatic fibrosis.

  14. 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

  15. Zerumbone induced apoptosis in liver cancer cells via modulation of Bax/Bcl-2 ratio

    PubMed Central

    Sharifah Sakinah, SA; Tri Handayani, S; Azimahtol Hawariah, LP

    2007-01-01

    Background Zerumbone is a cytotoxic component isolated from Zingiber zerumbet Smith, a herbal plant which is also known as lempoyang. This new anticancer bioactive compound from Z. zerumbet was investigated for its activity and mechanism in human liver cancer cell lines. Results Zerumbone significantly showed an antiproliferative activity upon HepG2 cells with an IC50 of 3.45 ± 0.026 μg/ml. Zerumbone was also found to inhibit the proliferation of non-malignant Chang Liver and MDBK cell lines. However the IC50 obtained was higher compared to the IC50 for HepG2 cells (> 10 μg/ml). The extent of DNA fragmentation was evaluated by the Tdt-mediated dUTP nick end labelling assay which showed that, zerumbone significantly increased apoptosis in HepG2 cells in a time-course manner. In detail, the apoptotic process triggered by zerumbone involved the up-regulation of pro-apoptotic Bax protein and the suppression of anti-apoptotic Bcl-2 protein expression. The changes that occurred in the levels of this antagonistic proteins Bax/Bcl-2, was independent of p53 since zerumbone did not affect the levels of p53 although this protein exists in a functional form. Western blotting analysis for Bax protein was further confirmed qualitatively with an immunoassay that showed the distribution of Bax protein in zerumbone-treated cells. Conclusion Therefore, zerumbone was found to induce the apoptotic process in HepG2 cells through the up and down regulation of Bax/Bcl-2 protein independently of functional p53 activity. PMID:17407577

  16. 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

  17. Conjugated linoleic acid induces apoptosis of murine mammary tumor cells via Bcl-2 loss

    PubMed Central

    Ou, Lihui; Ip, Clement; Lisafeld, Barbara; Ip, Margot M.

    2007-01-01

    Conjugated linoleic acid (CLA) is a powerful anticancer agent in a number of tumor model systems; however, its precise mechanism of action remains elusive. Here, we report that t10,c12 CLA, a component of synthetic CLA supplements, induced apoptosis and G1 arrest of p53 mutant TM4t murine mammary tumor cells. Furthermore, t10,c12-CLA induced a time- and concentration-dependent cleavage of caspases-3 and -9, and release of cytochrome c from mitochondria to cytosol. Levels of Bcl-2 protein were decreased both in total cellular lysates and in mitochondria after t10,c12-CLA treatment; however, there was no significant change in Bax or Bak. Overexpression of Bcl-2 attenuated apoptosis in response to t10,c12-CLA treatment. These results demonstrate that t10,c12-CLA triggers apoptosis of p53 mutant murine mammary tumor cells through the mitochondrial pathway by targeting Bcl-2. PMID:17400188

  18. Cytokine-mediated protection of human dendritic cells from prostate cancer-induced apoptosis is regulated by the Bcl-2 family of proteins.

    PubMed

    Pirtskhalaishvili, G; Shurin, G V; Esche, C; Cai, Q; Salup, R R; Bykovskaia, S N; Lotze, M T; Shurin, M R

    2000-08-01

    Prostate cancer is the most common cancer in men in the United States, and second in cancer-induced mortality. It is likely that tumour-induced immunosuppression is one of the reasons for low treatment efficacy in patients with advanced prostate cancer. It has been recently demonstrated that prostate cancer tissue is almost devoid of dendritic cells (DC), the major antigen-presenting cells responsible for the induction of specific antitumour immune responses. In this study, we have tested the hypothesis that prostate cancer induces progressive suppression of the DC system. We found that co-incubation of human DC with three prostate cancer cell lines led to the high levels of premature apoptosis of DC, which were significantly higher than in DC cultures co-incubated with normal prostate cells or blood leucocytes. Stimulation of DC for 24 hours with CD40 ligand (CD154), IL-12 or IL-15 prior to their co-incubation with prostate cancer cells resulted in a significant increase in DC survival in the tumour microenvironment. Furthermore, activation of DC with these cytokines was also accompanied by increased expression of the anti-apoptotic protein Bcl-x(L) in DC, suggesting a possible mechanism involved in DC protection from apoptotic death. In summary, our data demonstrate that prostate cancer induces active elimination of DC in the tumour microenvironment. Stimulation of DC by CD154, IL-12 or IL-15 leads to an increased expression of the anti-apoptotic protein Bcl-x(L) and increased resistance of DC to prostate cancer-induced apoptosis. These results suggest a new mechanism of tumour escape from immune recognition and demonstrate the cytokine-based approaches which might significantly increase the efficacy of DC-based therapies for cancer.

  19. Sigma-1 Receptors Regulate Bcl-2 Expression by Reactive Oxygen Species-Dependent Transcriptional Regulation of Nuclear Factor κB

    PubMed Central

    Meunier, Johann

    2010-01-01

    The expression of Bcl-2, the major antiapoptotic member of the Bcl-2 family, is under complex controls of several factors, including reactive oxygen species (ROS). The σ-1 receptor (Sig-1R), which was recently identified as a novel molecular chaperone at the mitochondria-associated endoplasmic reticulum membrane (MAM), has been shown to exert robust cellular protective actions. However, mechanisms underlying the antiapoptotic action of the Sig-1R remain to be clarified. Here, we found that the Sig-1R promotes cellular survival by regulating the Bcl-2 expression in Chinese hamster ovary cells. Although both Sig-1Rs and Bcl-2 are highly enriched at the MAM, Sig-1Rs neither associate physically with Bcl-2 nor regulate stability of Bcl-2 proteins. However, Sig-1Rs tonically regulate the expression of Bcl-2 proteins. Knockdown of Sig-1Rs down-regulates whereas overexpression of Sig-1Rs up-regulates bcl-2 mRNA, indicating that the Sig-1R transcriptionally regulates the expression of Bcl-2. The effect of Sig-1R small interfering RNA down-regulating Bcl-2 was blocked by ROS scavengers and by the inhibitor of the ROS-inducible transcription factor nuclear factor κB (NF-κB). Knockdown of Sig-1Rs up-regulates p105, the precursor of NF-κB, while concomitantly decreasing inhibitor of nuclear factor-κBα. Sig-1R knockdown also accelerates the conversion of p105 to the active form p50. Lastly, we showed that knockdown of Sig-1Rs potentiates H2O2-induced apoptosis; the action is blocked by either the NF-κB inhibitor oridonin or overexpression of Bcl-2. Thus, these findings suggest that Sig-1Rs promote cell survival, at least in part, by transcriptionally regulating Bcl-2 expression via the ROS/NF-κB pathway. PMID:19855099

  20. [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.

  1. 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

  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. Curcumin Significantly Enhances Dual PI3K/Akt and mTOR Inhibitor NVP-BEZ235-Induced Apoptosis in Human Renal Carcinoma Caki Cells through Down-Regulation of p53-Dependent Bcl-2 Expression and Inhibition of Mcl-1 Protein Stability

    PubMed Central

    Cho, Il Je; Kim, Sang Chan; Kwon, Taeg Kyu

    2014-01-01

    The PI3K/Akt and mTOR signaling pathways are important for cell survival and growth, and they are highly activated in cancer cells compared with normal cells. Therefore, these signaling pathways are targets for inducing cancer cell death. The dual PI3K/Akt and mTOR inhibitor NVP-BEZ235 completely inhibited both signaling pathways. However, NVP-BEZ235 had no effect on cell death in human renal carcinoma Caki cells. We tested whether combined treatment with natural compounds and NVP-BEZ235 could induce cell death. Among several chemopreventive agents, curcumin, a natural biologically active compound that is extracted from the rhizomes of Curcuma species, markedly induced apoptosis in NVP-BEZ235-treated cells. Co-treatment with curcumin and NVP-BEZ235 led to the down-regulation of Mcl-1 protein expression but not mRNA expression. Ectopic expression of Mcl-1 completely inhibited curcumin plus NVP-NEZ235-induced apoptosis. Furthermore, the down-regulation of Bcl-2 was involved in curcumin plus NVP-BEZ235-induced apoptosis. Curcumin or NVP-BEZ235 alone did not change Bcl-2 mRNA or protein expression, but co-treatment reduced Bcl-2 mRNA and protein expression. Combined treatment with NVP-BEZ235 and curcumin reduced Bcl-2 expression in wild-type p53 HCT116 human colon carcinoma cells but not p53-null HCT116 cells. Moreover, Bcl-2 expression was completely reversed by treatment with pifithrin-α, a p53-specific inhibitor. Ectopic expression of Bcl-2 also inhibited apoptosis in NVP-BE235 plus curcumin-treated cells. In contrast, NVP-BEZ235 combined with curcumin did not have a synergistic effect on normal human skin fibroblasts and normal human mesangial cells. Taken together, combined treatment with NVP-BEZ235 and curcumin induces apoptosis through p53-dependent Bcl-2 mRNA down-regulation at the transcriptional level and Mcl-1 protein down-regulation at the post-transcriptional level. PMID:24743574

  4. Bryostatin induces protein kinase C modulation, Mcl-1 up-regulation and phosphorylation of Bcl-2 resulting in cellular differentiation and resistance to drug-induced apoptosis in B-cell chronic lymphocytic leukemia cells.

    PubMed

    Thomas, Alun; Pepper, Chris; Hoy, Terry; Bentley, Paul

    2004-05-01

    Bryostatin, a macrocyclic lactone and protein kinase C (PKC) modulator, has been shown to have differentiation and anti-tumor activity against several leukemia cell lines in vitro. In this study, we demonstrated Bryostatin-induced differentiation in B-cell chronic lymphocytic leukemia (B-CLL) cells, characterized by an increase in cell size and a marked up-regulation of CD11c expression. The specific inhibitors of the extracellular signal-regulated kinase (ERK) and protein kinase C pathways, PD98059 and GF 109203X respectively, each completely blocked Bryostatin-induced differentiation of B-CLL cells, suggesting that activation of the ERK pathway plays a direct role in this process in a PKC-dependent manner. Furthermore, Bryostatin reduced both spontaneous and drug-induced apoptosis with chlorambucil, fludarabine and 2-chloro-2'-deoxyadenosine (2-Cda) in B-CLL cells. This resistance was associated with an early up-regulation of the anti-apoptotic protein Mcl-1 and post-translational phosphorylation of Bcl-2 at serine 70. The anti-apoptotic effects of Bryostatin were abrogated by GF 109203X, and to a lesser extent by the phosphatidylinositol 3-kinase (PI3-kinase) inhibitor, LY294002. Interestingly, the ERK inhibitor, PD98059 inhibited Mcl-1 expression but had little effect on Bryostatin-induced survival suggesting that the ERK pathway predominantly affects differentiation. Taken together these results present an explanation for Bryostatin-induced B-CLL cell survival in which modulation of the PKC pathway couples differentiation with an increase in antiapoptotic protein expression and calls into question the rationale for its use in the treatment of B-CLL.

  5. The Bcl-2 homology domain 3 (BH3) mimetic ABT-737 reveals the dynamic regulation of bad, a proapoptotic protein of the Bcl-2 family, by Bcl-xL.

    PubMed

    Ezzoukhry, Zakaria; Louandre, Christophe; François, Catherine; Saidak, Zuzana; Godin, Corinne; Mazière, Jean-Claude; Galmiche, Antoine

    2011-06-01

    The proteins of the B-cell lymphoma 2 (Bcl-2) family are important regulators of apoptosis under normal and pathological conditions. Chemical compounds that block the antiapoptotic proteins of this family have been introduced, such as 4-[4-[(4'-Chloro[1,1'-biphenyl]-2-yl)methyl]-1-piperazinyl]-N-[[4-[[(1R)-3-(dimethylamino)-1-[(phenylthio)methyl]propyl]amino]-3-nitrophenyl]sulfonyl]benzamide (ABT-737), a BH3-mimetic that neutralizes Bcl-2 and Bcl-xL. In this study, we used ABT-737 to explore the dynamic regulation of Bcl-2 proteins in living cells of different origins. Using ABT-737 as well as RNA interference or the application of growth factors, we examined the impact of the functional availability of the antiapoptotic proteins Bcl-2 and Bcl-2-extra large (Bcl-xL) on the Bcl-2 network. We report that ABT-737 increases the expression of Bcl-2-associated death promoter (Bad), a proapoptotic partner of the proteins Bcl-2 and Bcl-xL. Our observations indicate that Bad overexpression induced by ABT-737 results from the control of its normally rapid protein turnover, leading to the stabilization of this protein. We demonstrate the relevance of Bad post-translational regulation by Bcl-xL to the physiological setting using RNA interference against Bcl-xL as well as the application of epidermal growth factor, a growth factor that promotes the dissociation of Bad from Bcl-xL. Our results highlight a new facet of the mode of action of the antiapoptotic proteins Bcl-2 and Bcl-xL consisting of the regulation of the stability of the protein Bad. Finally, our results shed light on the mode of action of ABT-737, currently the best characterized inhibitor of the antiapoptotic proteins of the Bcl-2 family, and bear important implications regarding its use as an anticancer drug.

  6. IMPORTANCE OF APOPTOSIS MARKERS (MDM2, BCL-2 AND Bax) IN BENIGN PROSTATIC HYPERPLASIA AND PROSTATE CANCER.

    PubMed

    Saker, Z; Tsintsadze, O; Jiqia, I; Managadze, L; Chkhotua, A

    2015-12-01

    MDM2, Bcl-2 and Bax are well recognized markers of apoptosis. The goal of the current study was evaluation of the activity of these markers in different cells of BPH, PCa and hormonally treated prostate cancer (CRPCa) tissues. Activity of the markers has been evaluated in: 39 BPH, 28 prostate cancer (PCa) and 10 castration resistant PCa (CRPCa) tissues. Possible association of intensity of the expression with the disease clinical parameters has been assessed. Activity of MDM2 was higher in PCa and CRPCa as compared with BPH. This difference has been detected in epithelial and vascular prostatic cells. Epithelial activity of Bcl-2 was significantly lower in BPH as compared with PCa and CRPCa. Conversely, intensity of pro-apoptotic protein Bax was significantly higher in PBH than in PCa and CRPCa. The Bax activity in acinar and ductal cells of BPH was positively correlated with age. Intensity of Bcl-2 was significantly increasing, while activity of Bax was decreasing with increasing prostate volume. Significant correlation has been detected with the markers' activity and residual urine. In particular, MDM2 activity was increasing while epithelial activity of Bax was decreasing with increasing residual urine. Serum PSA level was positively correlated with MDM2 and negatively correlated with Bax activity. p27(Kip1) cell cycle inhibitor was positively correlated with Bax but negatively correlated with Bcl-2 activities. Proliferation marker Ki67 was positively correlated with MDM2 and Bcl-2. With increasing Ki67, Bax activity was significantly decreasing. Cyclin D3 was positively correlated with Bax. This pilot study has shown importance of apoptosis markers in BPH and PCa. It is the first study showing complex interrelation between apoptosis and cell cycle regulating proteins in BPH and PCa.

  7. 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.

  8. 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.

  9. Aspirin-induced Bcl-2 translocation and its phosphorylation in the nucleus trigger apoptosis in breast cancer cells.

    PubMed

    Choi, Bo-Hwa; Chakraborty, Goutam; Baek, Kwanghee; Yoon, Ho Sup

    2013-10-11

    Here, we report that B-cell lymphoma 2 (Bcl-2) is a novel target molecule of aspirin in breast cancer cells. Aspirin influenced the formation of a complex by Bcl-2 and FKBP38 and induced the nuclear translocation of Bcl-2 and its phosphorylation. These events inhibited cancer cell proliferation and subsequently enhanced MCF-7 breast cancer cell apoptosis. Bcl-2 knockdown using small interfering RNA (siRNA) delayed apoptotic cell death, which correlated with increased proliferation following aspirin exposure. In contrast, Bcl-2 overexpression enhanced the onset of aspirin-induced apoptosis, which was also associated with a significant increase in Bcl-2 phosphorylation in the nucleus. Therefore, this study may provide novel insight into the molecular mechanism of aspirin, particularly its anticancer effects in Bcl-2- and estrogen receptor-positive breast cancer cells.

  10. Aspirin-induced Bcl-2 translocation and its phosphorylation in the nucleus trigger apoptosis in breast cancer cells

    PubMed Central

    Choi, Bo-Hwa; Chakraborty, Goutam; Baek, Kwanghee; Yoon, Ho Sup

    2013-01-01

    Here, we report that B-cell lymphoma 2 (Bcl-2) is a novel target molecule of aspirin in breast cancer cells. Aspirin influenced the formation of a complex by Bcl-2 and FKBP38 and induced the nuclear translocation of Bcl-2 and its phosphorylation. These events inhibited cancer cell proliferation and subsequently enhanced MCF-7 breast cancer cell apoptosis. Bcl-2 knockdown using small interfering RNA (siRNA) delayed apoptotic cell death, which correlated with increased proliferation following aspirin exposure. In contrast, Bcl-2 overexpression enhanced the onset of aspirin-induced apoptosis, which was also associated with a significant increase in Bcl-2 phosphorylation in the nucleus. Therefore, this study may provide novel insight into the molecular mechanism of aspirin, particularly its anticancer effects in Bcl-2- and estrogen receptor-positive breast cancer cells. PMID:24113271

  11. Thymoquinone induces apoptosis through downregulation of c-FLIP and Bcl-2 in renal carcinoma Caki cells.

    PubMed

    Park, Eun Jung; Chauhan, Anil Kumar; Min, Kyoung-Jin; Park, Dong Cheol; Kwon, Taeg Kyu

    2016-10-01

    Renal carcinoma is a common and frequently fatal carcinoma occurring worldwide and death rates due to this carcinoma are increasing with time. In the present study, we investigated the potential of thymoquinone a natural compound to induce apoptosis in renal carcinoma Caki cells. Thymoquinone efficiently enhanced the apoptotic population of Caki cells in a dose-dependent manner. Moreover, thymoquinone-mediated apoptosis caused downregulation of c-FLIP and Bcl-2, the master regulators of the anti-apoptotic mechanism. However, we did not find any changes in mRNA expression level of c-FLIP, therefore; this regulation of c-FLIP was a result of post-translation modification by thymoquinone. In contrast, expression of the Bcl-2 protein was observed at both transcriptional and translational level. However, we also observed that thymoquinone enhanced the level of intracellular reactive oxygen species (ROS) in Caki cells, which resulted in reduction of mitochondrial membrane potential (MMP) and cytochrome c release into cytoplasm. Our results postulate that thymoquinone induces apoptosis through downregulating c-FLIP and Bcl-2 which can be utilized as a chemotherapeutic agent to treat renal carcinoma.

  12. The potent peptide antagonist to angiogenesis, C16Y, and cisplatin act synergistically in the down-regulation of the Bcl-2/Bax ratio and the induction of apoptosis in human ovarian cancer cells.

    PubMed

    Shinagawa, Akiko; Yoshida, Yoshio; Kurokawa, Tetsuji; Horiuchi, Yuko; Tsuyoshi, Hideaki; Orisaka, Makoto; Sawamura, Yoko; Kleinman, Hynda K; Kotsuji, Fumikazu

    2011-12-01

    Cisplatin is one of the most potent antitumor agents for ovarian cancer, but has also been implicated in normal tissue cytotoxicity. We examined the effect of cisplatin alone and in combination with C16Y, a newly-identified anti-angiogenic peptide from the NH2-terminal domains of the γ-chain of laminin-1, on the modulation of Bcl-2/Bax expression and induction of apoptosis in ovarian cancer cells (OVACAR3). C16Y did not elicit cell death of human umbilical vein endothelial cells (HUVECs). Cisplatin exerted a lethal effect with an EC50 of 10 µM in OVACAR3s. In the presence of 25 or 50 µg/ml of C16Y (a range which has no effect against HUVECs), the EC50 for cisplatin in OVACAR3s decreased to 3.5 and 2.0 µM, respectively. Using fluorescence-activated cell sorting (FACS) analysis of DNA stained OVACAR3s and terminal deoxynucleotide tranferase-mediated dUTP nick end-labeling (TUNEL), we found that even at concentrations of 1 and 3 µM cisplatin, C16Y at 10 and 25 µg/ml increased the incidence of apoptosis in OVACAR3s by 3-5-fold. Each drug had some measurable effect on Bax protein expression. Furthermore, Bcl-2 protein expression levels were markedly reduced by C16Y alone and cisplatin alone in a dose-dependent manner. The combination of C16Y and cisplatin resulted in a further dramatic reduction in Bcl-2, underscoring the pronounced synergy produced by cisplatin and C16Y together. On the other hand, C16Y did not activate any other signal transduction pathways that usually culminate in the activation of apoptosis, such as the p53, p21waf1, p73, ERK1/2 or PI3-AKT pathways. These observations suggest that the suppression of the Bcl-2/Bax ratio may play an important role in mediating the synergistic effect of cisplatin and C16Y on the induction of apoptosis in OVACAR3 cells.

  13. Germ cell apoptosis and expression of Bcl-2 and Bax in porcine testis under normal and heat stress conditions.

    PubMed

    Fan, Xiaorui; Xi, Huaming; Zhang, Zhen; Liang, Yajun; Li, Qinghong; He, Junping

    2017-04-01

    increased and a redistribution of Bax from a cytoplasmic to a perinuclear or nuclear localization. This indicates that Bcl-2 and Bax may be involved in regulation of germ cell apoptosis induced by heat stress in boars. Copyright © 2016. Published by Elsevier GmbH.

  14. Apoptosis and expression of Bcl-2 and Bax in eutopic endometrium from women with endometriosis.

    PubMed

    Meresman, G F; Vighi, S; Buquet, R A; Contreras-Ortiz, O; Tesone, M; Rumi, L S

    2000-10-01

    To evaluate and compare spontaneous apoptosis and Bcl-2 and Bax expression in eutopic endometrium from women with and without endometriosis. Apoptosis and Bcl-2 and Bax expression were examined in eutopic endometrium from women with and without endometriosis. Instituto de Biología y Medicina Experimental-CONICET, Department of Gynecology and Department of Gynecological Pathology, Clínicas University Hospital, Buenos Aires, Argentina. Women with untreated endometriosis (n = 14) and controls (n = 16). Collection of endometrial samples during diagnostic or therapeutic laparoscopy. Apoptotic cells were detected with use of the dUTP nick-end labeling (TUNEL) assay; Bcl-2 and Bax expressions were assessed with use of immunohistochemical techniques. Spontaneous apoptosis was significantly lower in eutopic endometrium from patients with endometriosis, compared with healthy controls (2.26 +/- 0.53 and 9.37 +/- 1.69 apoptotic cells/field, respectively) and was independent of cycle phase. An increased expression of Bcl-2 protein was found in proliferative eutopic endometrium from patients with endometriosis. Bax expression was absent in proliferative endometrium, whereas there was an increase in its expression in secretory endometrium from both patients and controls. Women with endometriosis show decreased number of apoptotic cells in eutopic endometrium. The abnormal survival of endometrial cells may result in their continuing growth into ectopic locations.

  15. Vitis vinifera peel and seed gold nanoparticles exhibit chemopreventive potential, antioxidant activity and induce apoptosis through mutant p53, Bcl-2 and pan cytokeratin down-regulation in experimental animals.

    PubMed

    Nirmala, J Grace; Narendhirakannan, R T

    2017-05-01

    Several studies suggest surface modifications of gold nanoparticles (AuNPs) by capping agents or surface coatings could play an important role in biological systems, and site directed delivery. The present study was carried out to assess the antioxidant and apoptotic activities of the Vitis vinifera peel and seed gold nanoparticles in experimentally induced cancer in Swiss albino mice. 12-dimethylbenz [a] anthracene (DMBA) (single application) and 12-O-tetradecanoylphorbol 13-acetate (TPA) (thrice a week) were applied on the dorsal area of the skin to induce skin papillomagenesis in Swiss albino mice for 16 weeks. Gold nanoparticles were synthesized using Vitis vinifera peel and seed aqueous extracts and characterized by Transmission electron microscopic (TEM) analyses. On topical application, peel and seed gold nanoparticles demonstrated chemopreventive potential by significantly (p<0.05) reducing the cumulative number of tumors while increasing the antioxidant enzyme activities in the gold nanoparticles treated mice. The down-regulated expression of mutant p53, Bcl-2 and the levels of pan-cytokeratins might have facilitated the process of apoptosis in the chemical carcinogenesis process. The results were supported by the histopathological evaluation which exhibited mild dysplasia and acanthosis in the skin tissues of Vitis vinifera peel and seed AuNPs treated mice. Based on the present study, the chemopreventive action of Vitis vinifera peel and seed AuNPs is probably due to its ability to stimulate the antioxidant enzymes within the cells and suppressed abnormal skin cell proliferation that occurred during DMBA-induced skin papillomagenesis. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  16. Induction of B cell apoptosis by co-cross-linking CD23 and sIg involves aberrant regulation of c-myc and is inhibited by bcl-2.

    PubMed

    Campbell, K A; Studer, E J; Kilmon, M A; Lees, A; Finkelman, F; Conrad, D H

    1997-08-01

    A novel system to study the effects of co-cross-linking CD23/FceRII and sIg on murine B lymphocytes utilizes a highly multivalent form of anti-Ig prepared by covalently linking anti-Ig antibodies to a DNP-dextran backbone. CD23-sIg co-cross-linking is accomplished by the addition of DNP-specific monoclonal IgE. Previous studies demonstrated that co-cross-linking CD23 and sIg significantly inhibited mouse B cell proliferation, especially at high doses of the multivalent anti-Ig. Interestingly, examination of early activation signals reveals no difference in B cells subjected to co-cross-linking conditions as compared to B cells activated with anti-Ig alone. Total cellular protein tyrosine phosphorylation levels are unchanged by co-cross-linking. Analysis of B cell mRNA reveals that co-cross-linking the receptors does not alter the expression levels of ornithine decarboxylase 8 h after stimulation as compared to the controls. In contrast, levels of the proto-oncogene c-myc were significantly elevated 1 h after inducing B cell activation under co-cross-linking conditions. However, it remains unclear whether this aberrant c-myc regulation plays any role in inducing apoptosis. In addition, on day 3 after stimulation, the co-cross-linking of CD23 and sIg resulted in the formation of apoptotic B cells, determined by both photomicroscopy of the B cell cultures and FACS analysis of B cell nuclei. B cells obtained from bcl-2 transgenic mice proliferated as well as controls, and failed to undergo apoptosis when CD23 and sIg were co-cross-linked on their surface. These studies indicate that co-cross-linking of CD23 with B cell sIg inhibits B cell proliferation by a mechanism that is distinct from that seen by co-cross-linking of the Fc gamma RII and sIg. In addition, these results suggest a means by which antigen-specific IgE can down-regulate additional B cell activation and IgE synthesis.

  17. 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

  18. Virosecurinine induces apoptosis by affecting Bcl-2 and Bax expression in human colon cancer SW480 cells.

    PubMed

    Chen, Chuan-Rong; Xia, Yong-Hui; Yao, Shu-Yan; Zhang, Qing; Wang, Ying; Ji, Zhao-Ning

    2012-04-01

    Virosecurinine, the major alkaloid isolated from Securinega suffruticosa Pall Rehd was found to exhibit growth inhibition and cytotoxicity against huaman colon cancer SW480 cells via the microculture tetrazolium (MTT) assay. Due to its greater cytotoxic potency and selectivity towards SW480 cells, flow cytometry was used to analyze the cell cycle distribution of control and treated SW480 cells whereas Annexin V-FITC/PI flow cytometry analysis was carried out to confirm apoptosis induced by virosecurinine in SW480 cells. Apoptotic regulatory genes were determined by RT-PCR analysis. Virosecurinine was found to induce G1/S cell cycle arrest which led to predominantly apoptotic mode of cell death. Mechanistically, virosecurinine was found to up-regulated the Bax gene expression and down-regulated the Bcl-2 expression in SW480, The ratio of Bcl-2 to Bax was significantly decreased. Hence, we suggest that virosecurinine induced apoptosis in SW480 cells by affecting the expression of bcl-2 and bax.

  19. Jacarelhyperol A induced apoptosis in leukaemia cancer cell through inhibition the activity of Bcl-2 proteins.

    PubMed

    Zhang, Shoude; Yin, Jun; Li, Xia; Zhang, Jigang; Yue, Rongcai; Diao, Yanyan; Li, Honglin; Wang, Hui; Shan, Lei; Zhang, Weidong

    2014-09-22

    Hypericum japonicum Thunb. ex Murray is widely used as an herbal medicine for the treatment of hepatitis and tumours in China. However, the molecular mechanisms of its effects are unclear. Our previous research showed that extracts of H. japonicum can induce apoptosis in leukaemia cells. We also previously systematically analysed and isolated the chemical composition of H. japonicum. The fluorescence polarisation experiment was used to screen for inhibitors of Bcl-2 proteins which are proved as key proteins in apoptosis. The binding mode was modelled by molecular docking. We investigated the proliferation attenuating and apoptosis inducing effects of active compound on cancer cells by MTT assay and flow cytometry analysis. Activation of caspases were tested by Western blot. A broad-spectrum caspase inhibitor Z-VAD-FMK was used to investigate the caspases-dependence. In addition, co-immunoprecipitation was performed to analyse the inhibition of heterodimerization between anti-apoptotic Bcl-2 proteins with pro-apoptotic proteins. Moreover, in vivo activity was tested in a mouse xenograph tumour model. Jacarelhyperol A (Jac-A), a characteristic constituent of H. japonicum, was identified as a potential Bcl-2 inhibitor. Jac-A showed binding affinities to Bcl-xL, Bcl-2, and Mcl-1 with Ki values of 0.46 μM, 0.43 μM, and 1.69 μM, respectively. This is consistent with computational modelling results, which show that Jac-A presents a favorable binding mode with Bcl-xL in the BH3-binding pocket. In addition, Jac-A showed potential growth inhibitory activity in leukaemia cells with IC50 values from 1.52 to 6.92 μM and significantly induced apoptosis of K562 cells by promoting release of cytochrome c and activating the caspases. Jac-A also been proved that its effect is partly caspases-dependent and can disrupt the heterodimerization between anti-apoptotic Bcl-2 proteins with pro-apoptotic proteins. Moreover, Jac-A dose-dependently inhibited human K562 cell growth in a

  20. 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

  1. 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

  2. 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.

  3. 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.

  4. Activation of Bcl-2-Caspase-9 Apoptosis Pathway in the Testis of Asthmatic Mice

    PubMed Central

    Li, Junjuan; Ding, Zhaolei; Sheng, Jianhui; Li, Juan; Tan, Wei

    2016-01-01

    Background Apoptosis plays a critical role in controlling the proliferation and differentiation of germ cells during spermatogenesis. Dysregulation of the fine-tuned balance may lead to the onset of testicular diseases. In this study, we investigated the activation status of apoptosis pathways in the testicular tissues under the background of an asthmatic mouse model. Methods Ten BALB/c mice were divided into two groups: the acute asthma group and the control group. In the acute asthma group, ovalbumin (OVA)-sensitized mice were challenged with aerosolized OVA for 7 days, while the control group was treated with physiological saline. After that, both epididymis and testis were collected to determine the sperm count and motility. Apoptosis in the testis was evaluated by DNA ladder, immunochemistry and further by PCR array of apoptosis-related genes. Finally, the cleavage of caspase-3 and poly ADP-ribose polymerase (PARP) was determined by western blot and the enzymatic activities of caspase-9 and 3/7 were assessed using Caspase-Glo kits. Results Compared with control mice, significant decreases in the body weight, testis weight, sperm count and motility were seen in the experimental group. DNA ladder and immunochemistry showed significant increase in apoptotic index of the asthmatic testis, whereas a decrease in mRNA expression of Bcl-2 and increases in Bax, BNIP3, caspase-9, and AIF were observed in the asthma group. Furthermore, protein levels of AIF were significantly upregulated, while the translational expression of Bcl-2 was downregulated markedly. Consistently, caspase-9 activity in the testis of asthma mice was significantly higher than that of the control group. Conclusion Collectively, these results showed that Bcl-2-caspase-9 apoptosis pathway was clearly activated in the testis of asthmatic mice with the increased expression of apoptosis-related genes and proteins. To our knowledge, this is the first report demonstrating that asthma could lead to the

  5. Activation of Bcl-2-Caspase-9 Apoptosis Pathway in the Testis of Asthmatic Mice.

    PubMed

    Xu, Wenyuan; Guo, Guifang; Li, Junjuan; Ding, Zhaolei; Sheng, Jianhui; Li, Juan; Tan, Wei

    2016-01-01

    Apoptosis plays a critical role in controlling the proliferation and differentiation of germ cells during spermatogenesis. Dysregulation of the fine-tuned balance may lead to the onset of testicular diseases. In this study, we investigated the activation status of apoptosis pathways in the testicular tissues under the background of an asthmatic mouse model. Ten BALB/c mice were divided into two groups: the acute asthma group and the control group. In the acute asthma group, ovalbumin (OVA)-sensitized mice were challenged with aerosolized OVA for 7 days, while the control group was treated with physiological saline. After that, both epididymis and testis were collected to determine the sperm count and motility. Apoptosis in the testis was evaluated by DNA ladder, immunochemistry and further by PCR array of apoptosis-related genes. Finally, the cleavage of caspase-3 and poly ADP-ribose polymerase (PARP) was determined by western blot and the enzymatic activities of caspase-9 and 3/7 were assessed using Caspase-Glo kits. Compared with control mice, significant decreases in the body weight, testis weight, sperm count and motility were seen in the experimental group. DNA ladder and immunochemistry showed significant increase in apoptotic index of the asthmatic testis, whereas a decrease in mRNA expression of Bcl-2 and increases in Bax, BNIP3, caspase-9, and AIF were observed in the asthma group. Furthermore, protein levels of AIF were significantly upregulated, while the translational expression of Bcl-2 was downregulated markedly. Consistently, caspase-9 activity in the testis of asthma mice was significantly higher than that of the control group. Collectively, these results showed that Bcl-2-caspase-9 apoptosis pathway was clearly activated in the testis of asthmatic mice with the increased expression of apoptosis-related genes and proteins. To our knowledge, this is the first report demonstrating that asthma could lead to the activation of the mitochondrial apoptosis

  6. 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.

  7. 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

  8. 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

  9. 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

  10. 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

  11. 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.

  12. Oestrogen-mediated suppression of tumour necrosis factor alpha-induced apoptosis in MCF-7 cells: subversion of Bcl-2 by anti-oestrogens.

    PubMed

    Burow, M E; Weldon, C B; Tang, Y; McLachlan, J A; Beckman, B S

    2001-11-01

    In oestrogen receptor (ER)-positive breast carcinoma cells, 17beta-oestradiol suppresses a dose-dependent induction of cell death by tumour necrosis factor alpha (TNF). The ability of oestrogens to promote cell survival in ER-positive breast carcinoma cells is linked to a coordinate increase in Bcl-2 expression, an effect that is blocked with the pure anti-oestrogen ICI 182,780. The role of Bcl-2 in MCF-7 cell survival was confirmed by stable overexpression of Bcl-2 which resulted in suppression of apoptosis induced by doxorubicin (DOX), paclitaxel (TAX) and TNF as compared to vector-control cells. The pure anti-oestrogen ICI 182,780 in combination with TNF, DOX or TAX potentiated apoptosis in vector-transfected cells. Interestingly, pre-treatment with ICI 182,780 markedly enhanced chemotherapeutic drug- or TNF-induced apoptosis in Bcl-2 expressing cells, an effect that was correlated with ICI 182,780 induced activation of c-Jun N-terminal kinase. Our results suggest that the effects of oestrogens/anti-oestrogens on the regulation of apoptosis may involve coordinate activation of signalling events and Bcl-2 expression.

  13. 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.

  14. 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

  15. 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.

  16. Activation of the Proapoptotic Bcl-2 Protein Bax by a Small Molecule Induces Tumor Cell Apoptosis

    PubMed Central

    Zhao, Guoping; Zhu, Yanglong; Eno, Colins O.; Liu, Yanlong; DeLeeuw, Lynn; Burlison, Joseph A.; Chaires, Jonathan B.; Trent, John O.

    2014-01-01

    The proapoptotic Bcl-2 protein Bax by itself is sufficient to initiate apoptosis in almost all apoptotic paradigms. Thus, compounds that can facilitate disruptive Bax insertion into mitochondrial membranes have potential as cancer therapeutics. In our study, we have identified small-molecule compounds predicted to associate with the Bax hydrophobic groove by a virtual-screen approach. Among these, one lead compound (compound 106) promotes Bax-dependent but not Bak-dependent apoptosis. Importantly, this compound alters Bax protein stability in vitro and promotes the insertion of Bax into mitochondria, leading to Bax-dependent permeabilization of the mitochondrial outer membrane. Furthermore, as a single agent, compound 106 inhibits the growth of transplanted tumors, probably by inducing apoptosis in tumors. Our study has revealed a compound that activates Bax and induces Bax-dependent apoptosis, which may lead to the development of new therapeutic agents for cancer. PMID:24421393

  17. 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.

  18. 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.

  19. Iridovirus Bcl-2 protein inhibits apoptosis in the early stage of viral infection.

    PubMed

    Lin, Pei-Wen; Huang, Yi-Jen; John, Joseph Abraham Christopher; Chang, Ya-Nan; Yuan, Chung-Hsiang; Chen, Wen-Ya; Yeh, Chiao-Hwa; Shen, San-Tai; Lin, Fu-Pang; Tsui, Wen-Huei; Chang, Chi-Yao

    2008-01-01

    The grouper iridovirus (GIV) belongs to the family Iridoviridae, whose genome contains an antiapoptotic B-cell lymphoma (Bcl)-2-like gene. This study was carried-out to understand whether GIV blocks apoptosis in its host. UV-irradiated grouper kidney (GK) cells underwent apoptosis. However, a DNA fragmentation assay of UV-exposed GK cells after GIV infection revealed an inhibition of apoptosis. The UV- or heat-inactivated GIV failed to inhibit apoptosis, implying that a gene or protein of the viral particle might contribute to an apoptosis inhibitory function. The DNA ladder assay for GIV-infected GK cells after UV irradiation confirmed that apoptosis inhibition was an early process which occurred as early as 5 min post-infection. A GIV-Bcl sequence comparison showed distant sequence similarities to that of human and four viruses; however, all possessed the putative Bcl-2 homology (BH) domains of BH1, BH2, BH3, and BH4, as well as a transmembrane domain. Northern blot hybridization showed that GIV-Bcl transcription began at 2 h post-infection, and the mRNA level significantly increased in the presence of cycloheximide or aphidicolin, indicating that this GIV-Bcl is an immediate-early gene. This was consistent with the Western blot results, which also revealed that the virion carries the Bcl protein. We observed the localization of GIV-Bcl on the mitochondrial membrane and other defined intracellular areas. By immunostaining, it was proven that GIV-Bcl-expressing cells effectively inhibited apoptosis. Taken together, these results demonstrate that GIV inhibits the promotion of apoptosis by GK cells, which is mediated by the immediate early expressed viral Bcl gene.

  20. [Aitongxiao recipe regulated survivin and Bcl- 2 in rats' transplanted hepatoma carcinoma cell].

    PubMed

    Wang, Shu-jie; Wei, Ai-ling; Zhang, Yong-qin

    2012-12-01

    To study the main mechanisms of Aitongxiao Recipe (ATXR) for anti-tumor at the molecular level, and to clarify different efficient drugs' roles in anti-tumor, thus in-depth explaining the objectivity and substance of "cancer toxic" theory. Walker-256 tumor strain was used for Wistar rat transplanted liver cancer modeling. After successful modeling rats were randomly divided into 5 groups, i. e., the ATXP group, the qi regulating and blood circulating group (as the assembled I group), the heat clearing and detoxification group (as the assembled II group), the body resistance strengthening and cultivating group (as the assembled III group), and the model group, 10 in each group. Corresponding medication was given to rats in each group for 14 successive days. Finally rats were sacrificed and the tumor mass was taken out. The apoptosis rate and the cell cycle of tumor cells were detected by flow cytometry Annexin V/PI. The protein and mRNA expressions of Bcl-2 and survivin were detected using immunohistochemistry and real-time fluorescent quantitative PCR. (1) The apoptosis of hepatoma carcinoma cells could be obviously promoted in the ATXP group. The cell cycle could also be affected, making major cells arrest at G0/G1 phase. The proliferation of hepatoma carcinoma cells was effectively prevented. The efficacy in the assembled II group was in line with that in the ATXP group with no statistical difference (P>0.05). It was also effective in the assembled III group, but its efficacy was not as good as that in the former two groups, showing statistical difference (P<0.01). (2) ATXP could obviously down-regulate the protein and mRNA expressions of Bcl-2 and survivin in hepatoma carcinoma cells. Drugs for heat clearing and detoxification showed significant effects on down-regulating the protein and mRNA expressions of Bcl-2 and survivin in hepatoma carcinoma cells. Their effects were similar to that of ATXP (P>0.05). The effects of drugs for body resistance strengthening

  1. 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).

  2. 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.

  3. Combined treatment with ABT-737 and VX-680 induces apoptosis in Bcl-2- and c-FLIP-overexpressing breast carcinoma cells.

    PubMed

    Choi, Jung Eun; Woo, Seon Min; Min, Kyoung-Jin; Kang, Su Hwan; Lee, Soo Jung; Kwon, Taeg Kyu

    2015-03-01

    ABT-737, a BH3-mimetic small-molecule inhibitor, binds with very high affinity to Bcl-2, Bcl-xL and Bcl-w, and inhibits their activity. Aurora kinase is one of the serine/threonine kinase family members and is a vital and critical regulator of mitosis and meiosis. In the present study, we investigated the effects and mechanisms of a combined treatment of ABT-737 and VX-680 (Aurora kinase inhibitor) in human breast cancer MDA-MB‑435S cells. ABT-737 plus VX-680 induced caspase-dependent apoptosis in the human breast cancer cells. Combined treatment with ABT-737 and VX-680 led to the downregulation of Bcl-2 expression at the transcriptional level and the downregulation of c-FLIP and Mcl-1 expression at the post-transcriptional level. Overexpression of Bcl-2 or c-FLIP could not block the induction of apoptosis caused by the combined treatment with ABT-737 and VX-680. However, overexpression of Mcl-1 partially inhibited the induction of apoptosis. In contrast, the combined treatment with ABT-737 and VX680 had no effect on the apoptosis in normal cells. Taken together, our study demonstrated that combined treatment with ABT-737 and VX-680 induced apoptosis in anti‑apoptotic protein (Bcl-2 or c-FLIP)-overexpressing cells.

  4. Enforced expression of the apoptosis inhibitor Bcl-2 ablates tolerance induction in DNA-reactive B cells through a novel mechanism

    PubMed Central

    Wang, Ying-Hua; Yan, Yi; Rice, Jeffrey S.; Volpe, Bruce T.; Diamond, Betty

    2011-01-01

    How self tolerance is maintained during B cell development in the bone marrow has been a focal area of study in immunology. Receptor editing, anergy and clonal deletion all play important roles in the regulation of autoimmunity in the immature population. The mechanisms of tolerance induction in the periphery, however, are less well characterized. Overexpression of the apoptosis inhibitor Bcl-2 rescues autoreactive B cells from deletion and can contribute to the development of autoimmune disease in certain genetic backgrounds. Using a peptide induced autoimmunity model, we recently identified a peripheral tolerance checkpoint in antigen-activated B cells that have undergone class switching and somatic hypermutation. At this checkpoint, receptor editing, induced by antigen engagement, dampened the autoantibody response. In this study, we show that receptor editing fails to be induced in antigen activated DNA-reactive B cells that overexpress Bcl-2 (Bcl-2 Tg). The failure to induce RAG and receptor editing is likely due, at least partially, to the lack of self antigen. First, the levels of circulating DNA and of apoptotic bodies in the spleen of Bcl-2 Tg mice are significantly lower than in control mice. Second, in Bcl-2 Tg mice, RAG can be induced in a population of antigen-activated B cells by providing exogenous soluble antigen. These data suggest that, in addition to its anti-apoptotic activity, Bcl-2 may indirectly inhibit tolerance induction in B cells acquiring anti-nuclear antigen reactivity after peripheral activation by limiting the availability of self antigen. PMID:21458954

  5. Rottlerin stimulates apoptosis in pancreatic cancer cells through interactions with proteins of the Bcl-2 family

    PubMed Central

    Ohno, Izumi; Eibl, Guido; Odinokova, Irina; Edderkaoui, Mouad; Damoiseaux, Robert D.; Yazbec, Moussa; Abrol, Ravinder; Goddard, William A.; Yokosuka, Osamu; Pandol, Stephen J.

    2010-01-01

    Rottlerin is a polyphenolic compound derived from Mallotus philipinensis. In the present study, we show that rottlerin decreased tumor size and stimulated apoptosis in an orthotopic model of pancreatic cancer with no effect on normal tissues in vivo. Rottlerin also induced apoptosis in pancreatic cancer (PaCa) cell lines by interacting with mitochondria and stimulating cytochrome c release. Immunoprecipitation results indicated that rottlerin disrupts complexes of prosurvival Bcl-xL with Bim and Puma. Furthermore, siRNA knockdown showed that Bim and Puma are necessary for rottlerin to stimulate apoptosis. We also showed that rottlerin and Bcl-2 and Bcl-xL inhibitor BH3I-2′ stimulate apoptosis through a common mechanism. They both directly interact with mitochondria, causing increased cytochrome c release and mitochondrial depolarization, and both decrease sequestration of BH3-only proteins by Bcl-xL. However, the effects of rottlerin and BH3I-2′ on the complex formation between Bcl-xL and BH3-only proteins are different. BH3I-2′ disrupts complexes of Bcl-xL with Bad but not with Bim or Puma, whereas rottlerin had no effect on the Bcl-xL interaction with Bad. Also BH3I-2′, but not rottlerin, required Bad to stimulate apoptosis. In conclusion, our results demonstrate that rottlerin has a potent proapoptotic and antitumor activity in pancreatic cancer, which is mediated by disrupting the interaction between prosurvival Bcl-2 proteins and proapoptotic BH3-only proteins. Thus rottlerin represents a promising novel agent for pancreatic cancer treatment. PMID:19762431

  6. 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."

  7. Expression of apoptosis regulatory proteins p53, bcl-2 and bax in recurrent aphthous ulceration.

    PubMed

    Pinto Rodrigues, J F N; Fujiyama Oshima, C T; Ribeiro Paiotti, A P; Franco, M; Miki Ihara, S S; Ribeiro, D A

    2012-10-01

    Recurrent aphthous ulceration (RAU) is considered to be an acute inflammatory disease of unknown pathogenesis. Apoptosis may represent an important event in the control of inflammation. The aim of this study was to investigate apoptosis process in RAU using immunohistochemistry. We studied the expression and location of p53, bcl-2 and bax in ulcerated lesions clinically diagnosed as RAU (n = 12) and compared it with that of oral clinically normal mucosa (n = 6) and of other inflammatory chronic disease such as oral fibrous inflammatory hyperplasia (FIH; n = 18). Significant statistically differences (n < 0.05) in p53 expression were noticed in RAU when compared with normal mucosa. No significant statistically differences (P > 0.05) were noticed between FIH and RAU. Bcl-2 and bax did not show remarkable differences between groups. Taken together, the data suggest that RAU induces p53 immunoexpression. Therefore, the protein might be related to the aetiopathogenesis of the ulcerated oral lesions. © 2011 The Authors. Journal of the European Academy of Dermatology and Venereology © 2011 European Academy of Dermatology and Venereology.

  8. 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.

  9. 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.

  10. A brewing understanding of the regulation of Bax function by Bcl-xL and Bcl-2.

    PubMed

    Renault, Thibaud T; Dejean, Laurent M; Manon, Stéphen

    2017-01-01

    Bcl-2 family members form a network of protein-protein interactions that regulate apoptosis through permeabilization of the mitochondrial outer membrane. Deciphering this intricate network requires streamlined experimental models, including the heterologous expression in yeast. This approach had previously enabled researchers to identify domains and residues that underlie the conformational changes driving the translocation, the insertion and the oligomerization of the pro-apoptotic protein Bax at the level of the mitochondrial outer membrane. Recent studies that combine experiments in yeast and in mammalian cells have shown the unexpected effect of the anti-apoptotic protein Bcl-xL on the priming of Bax. As demonstrated with the BH3-mimetic molecule ABT-737, this property of Bcl-xL, and of Bcl-2, is crucial to elaborate about how apoptosis could be reactivated in tumoral cells.

  11. t-Darpp promotes cancer cell survival by up-regulation of Bcl2 through Akt-dependent mechanism.

    PubMed

    Belkhiri, Abbes; Dar, Altaf A; Zaika, Alexander; Kelley, Mark; El-Rifai, Wael

    2008-01-15

    t-Darpp is a cancer-related truncated isoform of Darpp-32 (dopamine and cyclic-AMP-regulated phosphoprotein of M(r) 32,000). We detected overexpression of t-Darpp mRNA in two thirds of gastric cancers compared with normal samples (P = 0.004). Using 20 micromol/L ceramide treatment as a model for induction of apoptosis in AGS cancer cells, we found that expression of t-Darpp led to an increase in Bcl2 protein levels and blocked the activation of caspase-3 and caspase-9. The MitoCapture mitochondrial apoptosis and cytochrome c release assays indicated that t-Darpp expression enforces the mitochondrial transmembrane potential and protects against ceramide-induced apoptosis. Interestingly, the expression of t-Darpp in AGS cells led to >or=2-fold increase in Akt kinase activity with an increase in protein levels of p-Ser(473) Akt and p-Ser(9) GSK3 beta. These findings were further confirmed using tetracycline-inducible AGS cells stably expressing t-Darpp. We also showed transcriptional up-regulation of Bcl2 using the luciferase assay with Bcl2 reporter containing P1 full promoter, quantitative reverse transcription-PCR, and t-Darpp small interfering RNA. The Bcl2 promoter contains binding sites for cyclic AMP-responsive element binding protein CREB/ATF1 transcription factors and using the electrophoretic mobility shift assay with a CREB response element, we detected a stronger binding in t-Darpp-expressing cells. The t-Darpp expression led to an increase in expression and phosphorylation of CREB and ATF-1 transcription factors that were required for up-regulating Bcl2 levels. Indeed, knockdown of Akt, CREB, or ATF1 in t-Darpp-expressing cells reduced Bcl2 protein levels. In conclusion, the t-Darpp/Akt axis underscores a novel oncogenic potential of t-Darpp in gastric carcinogenesis and resistance to drug-induced apoptosis.

  12. 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.

  13. SATB1 Mediates Long-Range Chromatin Interactions: A Dual Regulator of Anti-Apoptotic BCL2 and Pro-Apoptotic NOXA Genes

    PubMed Central

    Yang, Yin; Wang, Zongdan; Sun, Luan; Shao, Lipei; Yang, Nan; Yu, Dawei; Zhang, Xin; Han, Xiao; Sun, Yujie

    2015-01-01

    Aberrant expression of special AT-rich binding protein 1 (SATB1), a global genomic organizer, has been associated with various cancers, which raises the question of how higher-order chromatin structure contributes to carcinogenesis. Disruption of apoptosis is one of the hallmarks of cancer. We previously demonstrated that SATB1 mediated specific long-range chromosomal interactions between the mbr enhancer located within 3’-UTR of the BCL2 gene and the promoter to regulate BCL2 expression during early apoptosis. In the present study, we used chromosome conformation capture (3C) assays and molecular analyses to further investigate the function of the SATB1-mediated higher-order chromatin structure in co-regulation of the anti-apoptotic BCL2 gene and the pro-apoptotic NOXA gene located 3.4Mb downstream on Chromosome 18. We demonstrated that the mbr enhancer spatially juxtaposed the promoters of BCL2 and NOXA genes through SATB1-mediated chromatin-loop in Jurkat cells. Decreased SATB1 levels switched the mbr-BCL2 loop to mbr-NOXA loop, and thus changed expression of these two genes. The SATB1-mediated dynamic switch of the chromatin loop structures was essential for the cooperative expression of the BCL2 and NOXA genes in apoptosis. Notably, the role of SATB1 was specific, since inhibition of SATB1 degradation by caspase-6 inhibitor or caspase-6-resistant SATB1 mutant reversed expression of BCL-2 and NOXA in response to apoptotic stimulation. This study reveals the critical role of SATB1-organized higher-order chromatin structure in regulating the dynamic equilibrium of apoptosis-controlling genes with antagonistic functions and suggests that aberrant SATB1 expression might contribute to cancer development by disrupting the co-regulated genes in apoptosis pathways. PMID:26422397

  14. 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.

  15. Oral cancer-associated fibroblasts inhibit heat-induced apoptosis in Tca8113 cells through upregulated expression of Bcl-2 through the Mig/CXCR3 axis.

    PubMed

    Bian, Li; Sun, Xin; Jin, Kewei; He, Yongwen

    2012-12-01

    The aim of this study was to detect oral cancer-associated fibroblast-secreted cytokines and their regulation of heat-induced apoptosis in the human tongue squamous cell carcinoma cell line Tca8113. We isolated cancer-associated fibroblasts (CAFs) from human tongue squamous cell carcinoma and normal fibroblasts (NFs) from normal oral mucosa. The expression profiles of cytokines secreted by CAFs and those secreted by NFs were detected using the RayBio® human cytokine antibody microarray. The conditioned medium was prepared by mixing the CAF or NF supernatant cell culture medium with fresh complete medium. The expression levels of Bax, Bcl-2 and CXCR3 in Tca8113 cells were detected by western blot analysis. The heat-induced apoptosis ratio of the Tca8113 cells was detected by propidium iodide staining combined with flow cytometry. The quantity of the Mig factor, one of the chemokines secreted by CAFs, was clearly increased 19-fold when compared with the level in NFs. The conditioned medium of NFs had no obvious effect on the expression levels of Bax/Bcl-2 and the heat-induced apoptosis ratio in the Tca8113 cells. However, the expression levels of Bcl-2 were significantly upregulated and heat-induced Tca8113 cell apoptosis was inhibited in the CAF-conditioned medium. After adding neutralizing antibodies against Mig or its receptor CXCR3, the enhanced expression of the Bcl-2 protein and the inhibited heat-induced apoptosis of Tca8113 cells in the CAF-conditioned medium were significantly attenuated. CAFs may increase the expression levels of Bcl-2 through the paracrine secretion of Mig and reduce the thermosensitivity of Tca8113 cells.

  16. Bcl-2 family proteins as regulators of cancer cell invasion and metastasis: a review focusing on mitochondrial respiration and reactive oxygen species.

    PubMed

    Um, Hong-Duck

    2016-02-02

    Although Bcl-2 family proteins were originally identified as key regulators of apoptosis, an impressive body of evidence has shown that pro-survival members of the Bcl-2 family, including Bcl-2, Bcl-XL, and Bcl-w, can also promote cell migration, invasion, and cancer metastasis. Interestingly, cell invasion was recently found to be suppressed by multidomain pro-apoptotic members of the Bcl-2 family, such as Bax and Bak. While the mechanisms underlying these new functions of Bcl-2 proteins are just beginning to be studied, reactive oxygen species (ROS) have emerged as inducers of cell invasion and the production of ROS from mitochondrial respiration is known to be promoted and suppressed by the pro-survival and multidomain pro-apoptotic Bcl-2 family members, respectively. Here, I review the evidence supporting the ability of Bcl-2 proteins to regulate cancer cell invasion and metastasis, and discuss our current understanding of their underlying mechanisms, with a particular focus on mitochondrial respiration and ROS, which could have implications for the development of strategies to overcome tumor progression.

  17. 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

  18. 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.

  19. [The alterations of apoptosis factor Bcl-2/Bax in the early Parkinson's disease rats and the protective effect of scorpion venom derived activity peptide].

    PubMed

    Xu, Hong; An, Dong; Yin, Sheng-ming; Chen, Wei; Zhao, Dan; Meng, Xu; Yu, De-qin; Sun, Yi-ping; Zhao, Jie; Zhang, Wan-qin

    2015-05-01

    To explore the alterations of apoptosis factor Bcl-2/Bax in the early Parkinson's disease (PD) rats and the protective effect of scorpion venom derived bioactive peptide. Healthy male SD rats (180-220 g) were randomly divided into 4 groups (n = 10): early PD model group, sham operation group, scorpion venom derived bioactive peptide control group, scorpion venom derived bioactive peptide therapy group. 6-hydroxydopamine (6-OHDA) was used to prepare the early PD rat model. The immunohistochemistry was used to detect the expression of Bax and Bcl-2 and further explore the mechanism of anti-apoptosis regarding the neuroprotective effect of scorpion venom derived bioactive peptide. The results indicated that compared with the control rats, the immunostaining of Bax in the brain increased significantly while that of Bcl-2 decreased significantly in the lesion side of 6-OHDA treated rats. Interestingly, scorpion venom derived bioactive peptide could attenuate the above abnormal changes. Up-regulation of Bax and down-regulation of Bcl-2 could participate in the early stage of PD and the anti-apoptotic mechanism could be involved in the neuroprotective effect exerted by scorpion venom derived activity peptide regarding the dopaminergic neuron in the early stage.

  20. Effects of Recombinant Overexpression of Bcl2 on the Proliferation, Apoptosis, and Osteogenic/Odontogenic Differentiation Potential of Dental Pulp Stem Cells.

    PubMed

    Heng, Boon Chin; Ye, Xin; Liu, Yuan; Dissanayaka, Waruna Lakmal; Cheung, Gary Shun Pan; Zhang, Chengfei

    2016-04-01

    The therapeutic usefulness of dental pulp stem cells (DPSCs) is severely limited by low survivability upon transplantation in situ because of the presence of various proapoptotic factors within damaged/diseased tissues (ie, hypoxia and inflammation). One strategy to enhance the survivability of grafted DPSCs could be recombinant overexpression of antiapoptotic genes, such as the B-cell lymphoma 2 gene (Bcl2). DPSCs were transfected with the Bcl2 and/or GFP gene. Cell density and mitotic activity of transfected DPSCs within in vitro culture were evaluated with the water soluble tetrazolium salt-8 (WST-8) and bromodeoxyuridine assay, respectively, whereas apoptosis was evaluated through the detection of cytoplasmic histone-associated DNA fragments. The osteogenic/odontogenic differentiation potential of these cells was evaluated with quantitative real-time polymerase chain reaction, alkaline phosphatase, and alizarin red staining. Bcl2-transfected DPSCs exhibited consistently higher cell densities than the GFP-transfected control within in vitro culture, and this was not because of the higher mitotic rate but was instead attributed to enhanced cell survivability because of the inhibition of apoptosis by Bcl2. Recombinant overexpression of Bcl2 inhibited the osteogenic/odontogenic potential of DPSCs, as indicated by lower levels of alkaline phosphatase activity and mineralized calcium deposition, together with the down-regulated expression of several key osteogenic/odontogenic gene markers including collagen I, osteocalcin, dentin matrix protein-1, bone sialoprotein, and alkaline phosphatase. The results place a "caveat" or limitation on the use of recombinant Bcl2 overexpression as a therapeutic strategy for improving the survivability of grafted DPSCs in that the osteogenic/odontogenic potential of these cells may be compromised despite enhanced survival within the host. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights

  1. Safflor yellow B suppresses angiotensin II-mediated human umbilical vein cell injury via regulation of Bcl-2/p22{sup phox} expression

    SciTech Connect

    Wang, Chaoyun; He, Yanhao; Yang, Ming; Sun, Hongliu; Zhang, Shuping; Wang, Chunhua

    2013-11-15

    Intracellular reactive oxygen species (ROS) are derived from nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. Angiotensin II (Ang II) can cause endothelial dysfunction by promoting intracellular ROS generation. Safflor yellow B (SYB) effectively inhibits ROS generation by upregulating Bcl-2 expression. In this study, we examined the effects of SYB on Ang II-induced injury to human umbilical vein endothelial cells (HUVECs), and elucidated the roles of NADPH oxidase and Bcl-2. We treated cultured HUVECs with Ang II, SYB, and Bcl-2 siRNA, and determined NADPH oxidase activity and ROS levels. Furthermore, cellular and mitochondrial physiological states were evaluated, and the expression levels of target proteins were analyzed. Ang II significantly enhanced intracellular ROS levels, caused mitochondrial membrane dysfunction, and decreased cell viability, leading to apoptosis. This was associated with increased expression of AT1R and p22{sup phox}, increased NADPH oxidase activity, and an increased ratio of Bax/Bcl-2, leading to decreases in antioxidant enzyme activities, which were further strengthened after blocking Bcl-2. Compared to Ang II treatment alone, co-treatment with SYB significantly reversed HUVEC injury. Taken together, these results demonstrate that SYB could significantly protect endothelial cells from Ang II-induced cell damage, and that it does so by upregulating Bcl-2 expression and inhibiting ROS generation. - Highlights: • Angiotensin II depresses mitochondria physiological function. • Angiotensin II activates NADPH oxidase via up-regulating expresion of p22{sup phox}. • Bcl-2 plays a pivotal role in improving mitochondria function and regulates ROS level. • Inhibitor of Bcl-2 promotes angiotensin II mediated HUVEC injury. • SYB attenuates angiotensin II mediated HUVEC injury via up regulating Bcl-2 expression.

  2. 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.

  3. Millimeter wave radiation induces apoptosis via affecting the ratio of Bax/Bcl-2 in SW1353 human chondrosarcoma cells.

    PubMed

    Li, Xihai; Ye, Hongzhi; Cai, Liangliang; Yu, Fangrong; Chen, Wenlie; Lin, Ruhui; Zheng, Chunsong; Xu, Huifeng; Ye, Jinxia; Wu, Guangwen; Liu, Xianxiang

    2012-03-01

    The efficacy and safety of millimeter wave radiation has been proven for various types of malignant tumors. However, the mechanisms underlying effects of millimeter wave radiation on apoptosis are still unclear. The present study was undertaken to examine the effects of millimeter wave radiation on cell apoptosis and mitochondrial membrane potential, and to determine the molecular mechanism of millimeter wave radiation-induced apoptosis by investigating the expression of Bcl-2 family proteins (Bcl-2, Bax), caspase-9 and caspase-3 in SW1353 cells. We found that millimeter wave radiation suppressed the viability of SW1353 cells, demonstrating that millimeter wave radiation induced cell apoptosis and reduced cell viability in a time-dependent manner. Furthermore, we observed that treatment of cells with millimeter wave radiation significantly induced loss of mitochondrial membrane potential, upregulated proapoptotic Bax, caspase-9 and caspase-3, but did not significantly change levels of antiapoptotic Bcl-2. These data suggested that millimeter wave radiation may induce apoptosis via affecting the ratio of Bax/Bcl-2 in SW1353 cells.

  4. 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. Copyright

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

    PubMed Central

    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

    2015-01-01

    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 Ca2+ 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 [Ca2+] ([Ca2+]cyt) caused by ATP, while only the transient phase was observed in normal cells. Removal of extracellular Ca2+ eliminated the plateau phase increase of [Ca2+]cyt in lung cancer cells, indicating that the plateau phase of [Ca2+]cyt increase is due to Ca2+ 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 Ca2+ or chelating intracellular Ca2+ with BAPTA-AM significantly inhibited ATP-induced increase in Bcl-2/Bax ratio, indicating that a rise in [Ca2+]cyt through Ca2+ 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. PMID:26491047

  6. Bcl-2 proteins and autophagy regulate mitochondrial dynamics during programmed cell death in the Drosophila ovary

    PubMed Central

    Tanner, Elizabeth A.; Blute, Todd A.; Brachmann, Carrie Baker; McCall, Kimberly

    2011-01-01

    The Bcl-2 family has been shown to regulate mitochondrial dynamics during cell death in mammals and C. elegans, but evidence for this in Drosophila has been elusive. Here, we investigate the regulation of mitochondrial dynamics during germline cell death in the Drosophila melanogaster ovary. We find that mitochondria undergo a series of events during the progression of cell death, with remodeling, cluster formation and uptake of clusters by somatic follicle cells. These mitochondrial dynamics are dependent on caspases, the Bcl-2 family, the mitochondrial fission and fusion machinery, and the autophagy machinery. Furthermore, Bcl-2 family mutants show a striking defect in cell death in the ovary. These data indicate that a mitochondrial pathway is a major mechanism for activation of cell death in Drosophila oogenesis. PMID:21177345

  7. 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

  8. 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.

  9. 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.

  10. Cif (Cytochrome c Efflux-Inducing Factor) Activity Is Regulated by Bcl-2 and Caspases and Correlates with the Activation of Bid

    PubMed Central

    Han, Zhiyong; Bhalla, Kapil; Pantazis, Panayotis; Hendrickson, Eric A.; Wyche, James H.

    1999-01-01

    The cytosolic factor Cif (cytochrome c-efflux inducing factor) was activated by the apoptosis inducers staurosporine and anti-Fas antibodies and rapidly induced the efflux of cytochrome c from purified human mitochondria. HL-60 cells that stably overexpressed a bcl-2 cDNA transgene (Bcl-2:HL-60 cells) contained mitochondria and a cytosol that were resistant to exogenous Cif and that lacked detectable endogenous Cif activity, respectively. Therefore, Bcl-2 overexpression negated Cif activity and suggested that the requirement for Cif resides upstream of Bcl-2 on the apoptotic signal transduction pathway. The addition of purified caspase 3, caspase 7, or caspase 8 to the cytosolic extract from Bcl-2:HL-60 cells, however, restored Cif activity, demonstrating that the inhibition of Cif by Bcl-2 overexpression could be overcome by activated caspases. Moreover, the addition of purified caspases to cytosolic extracts prepared from parental HL-60 cells was also sufficient to cause Cif activation, suggesting that caspases might be required for Cif activation. Consistent with these observations, Fas-induced apoptosis in Jurkat cells resulted in caspase 8 activation and subsequently in activation of Cif. Finally, we demonstrate that the activation of Cif correlated with the activation of the Bcl-2 family member Bid by caspases and that Cif activity was selectively neutralized by anti-Bid antibodies. Taken together, these results indicate that Cif is identical to Bid and that it can be inhibited by Bcl-2 and activated by caspases. Thus, Cif (Bid) is an important biological regulator for the transduction of apoptotic signals. PMID:9891071

  11. Cif (Cytochrome c efflux-inducing factor) activity is regulated by Bcl-2 and caspases and correlates with the activation of Bid.

    PubMed

    Han, Z; Bhalla, K; Pantazis, P; Hendrickson, E A; Wyche, J H

    1999-02-01

    The cytosolic factor Cif (cytochrome c-efflux inducing factor) was activated by the apoptosis inducers staurosporine and anti-Fas antibodies and rapidly induced the efflux of cytochrome c from purified human mitochondria. HL-60 cells that stably overexpressed a bcl-2 cDNA transgene (Bcl-2:HL-60 cells) contained mitochondria and a cytosol that were resistant to exogenous Cif and that lacked detectable endogenous Cif activity, respectively. Therefore, Bcl-2 overexpression negated Cif activity and suggested that the requirement for Cif resides upstream of Bcl-2 on the apoptotic signal transduction pathway. The addition of purified caspase 3, caspase 7, or caspase 8 to the cytosolic extract from Bcl-2:HL-60 cells, however, restored Cif activity, demonstrating that the inhibition of Cif by Bcl-2 overexpression could be overcome by activated caspases. Moreover, the addition of purified caspases to cytosolic extracts prepared from parental HL-60 cells was also sufficient to cause Cif activation, suggesting that caspases might be required for Cif activation. Consistent with these observations, Fas-induced apoptosis in Jurkat cells resulted in caspase 8 activation and subsequently in activation of Cif. Finally, we demonstrate that the activation of Cif correlated with the activation of the Bcl-2 family member Bid by caspases and that Cif activity was selectively neutralized by anti-Bid antibodies. Taken together, these results indicate that Cif is identical to Bid and that it can be inhibited by Bcl-2 and activated by caspases. Thus, Cif (Bid) is an important biological regulator for the transduction of apoptotic signals.

  12. 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.

  13. Berberine alleviates preeclampsia possibly by regulating the expression of interleukin-2/interleukin-10 and Bcl-2/Bax.

    PubMed

    Wang, Ailan; Liu, Qingcui; Zhang, Jin; Zheng, Rui

    2015-01-01

    The present study is to investigate the effect of berberine on the expression of inflammatory factors interleukin (IL)-2 and IL-10, and the expression of apoptosis proteins Bcl-2 and Bax. A total of 70 SD rats were randomly divided into 7 equal groups, including normal non-pregnant group, normal pregnant group, preeclampsia group, preeclampsia + berberine (50, 100, and 200 mg/kg/day) groups, and preeclampsia + nifedipine (20 mg/kg/day) group. Blood pressure was measured before pregnancy, and on day 15 and 21 of pregnancy. Urines before pregnancy and on day 15 and 21 of pregnancy were collected for the determination of urine protein levels. Peripheral blood was collected from all rats on day 21 of pregnancy to measure the levels of blood urea nitrogen and creatinine. On day 21 of pregnancy, the weight of fetuses and placentas, and the number of normal fetuses were determined. Enzyme-linked immunosorbent assay was performed to determine the levels of IL-2 and IL-10 in plasma. Western blotting was used to measure the expression of Bcl-2 and Bax proteins in placenta of rats with preeclampsia. Treatment with berberine for seven days reduced blood pressure, urine proteins levels, and kidney function in rats with preeclampsia. Berberine improved the number of normal fetuses and the weight of fetuses and placentas from rats with preeclampsia. Berberine up-regulated IL-10 and down-regulated IL-2 in the peripheral blood of SD rats with preeclampsia. Berberine up-regulated Bcl-2 and down-regulated Bax in the placenta of SD rats with preeclampsia. Berberine increases the number and weight of normal fetuses in rats with preeclampsia, possibly by regulating the balance of IL-2 and IL-10, and inhibiting apoptosis.

  14. (-)-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.

  15. Regulation of anti-apoptotic Bcl-2 family protein Mcl-1 by S6 kinase 2

    PubMed Central

    Sridharan, Savitha

    2017-01-01

    The anti-apoptotic Bcl-2 family protein myeloid cell leukemia-1 (Mcl-1) plays an important role in breast cancer cell survival and chemoresistance. We have previously shown that knockdown of the 40S ribosomal protein S6 kinase-2 (S6K2), which acts downstream of the mechanistic target of rapamycin complex 1 (mTORC1), enhanced breast cancer cell death by apoptotic stimuli. The increase in cell death by S6K2 depletion was partly due to inactivation of Akt. In the present study, we investigated if S6K2 regulates Mcl-1, which acts downstream of Akt. Silencing of S6K2 but not S6K1 in T47D cells decreased Mcl-1 level, and potentiated apoptosis induced by TRAIL and doxorubicin. Knockdown of S6K2 also decreased the level of anti-apoptotic Bcl-xl. Depletion of the tumor suppressor protein PDCD4 (programmed cell death 4), which regulates translation of several anti-apoptotic proteins, reversed downregulation of Bcl-xl but not Mcl-1 and failed to reverse the effect of S6K2 knockdown on potentiation of doxorubicin-induced apoptosis. Downregulation of Mcl-1 by S6K2 knockdown was partly restored by the proteasome inhibitor MG132. Overexpression of catalytically-active Akt or knockdown of glycogen synthase kinase-3 (GSK3)-β, a substrate for Akt, had little effect on Mcl-1 downregulation caused by S6K2 deficiency. Silencing of S6K2 increased the level of c-Jun N-terminal kinase (JNK) and knockdown of JNK1 increased basal Mcl-1 level and partly reversed the effect of S6K2 knockdown on Mcl-1 downregulation. JNK1 knockdown also had a modest effect in attenuating the increase in doxorubicin-induced apoptosis caused by S6K2 deficiency. These results suggest that S6K2 regulates apoptosis via multiple mechanisms, and involves both Akt and JNK. PMID:28301598

  16. Distinct regions of the interleukin-7 receptor regulate different Bcl2 family members.

    PubMed

    Jiang, Qiong; Li, Wen Qing; Hofmeister, Robert R; Young, Howard A; Hodge, David R; Keller, Jonathan R; Khaled, Annette R; Durum, Scott K

    2004-07-01

    The antiapoptotic function of the interleukin-7 (IL-7) receptor is related to regulation of three members of the Bcl2 family: synthesis of Bcl2, phosphorylation of Bad, and cytosolic retention of Bax. Here we show that, in an IL-7-dependent murine T-cell line, different regions of the IL-7 receptor initiate the signal transduction pathways that regulate these proteins. Both Box1 and Y449 are required to signal Bcl2 synthesis and Bax cytosolic retention. This suggests a sequential model in which Jak1, which binds to Box1, is first activated and then phosphorylates Y449, leading to Bcl2 and Bax regulation, accounting for approximately 90% of the survival function. Phosphorylation of Bad required Box1 but not Y449, suggesting that Jak1 also initiates an additional signaling cascade that accounts for approximately 10% of the survival function. Stat5 was activated from the Y449 site but only partially accounted for the survival signal. Proliferation required both Y449 and Box1. Thymocyte development in vivo showed that deletion of Y449 eliminated 90% of alphabeta T-cell development and completely eliminated gammadelta T-cell development, whereas deleting Box 1 completely eliminated both alphabeta and gammadelta T-cell development. Thus the IL-7 receptor controls at least two distinct pathways, in addition to Stat5, that are required for cell survival.

  17. The Relationship between the Bcl-2/Bax Proteins and the Mitochondria-Mediated Apoptosis Pathway in the Differentiation of Adipose-Derived Stromal Cells into Neurons

    PubMed Central

    Wang, Quanquan; Zhang, Lili; Yuan, Xiaodong; Ou, Ya; Zhu, Xuhong; Cheng, Zanzan; Zhang, Pingshu; Wu, Xiaoying; Meng, Yan; Zhang, Liping

    2016-01-01

    Our objective is to study the relationship between the regulatory proteins Bcl-2/Bax and mitochondria-mediated apoptosis during the differentiation of adipose-derived stromal cells (ADSCs) into neurons. Immunocytochemistry and western blotting showed that the cells weakly expressed neuron-specific enolase (NSE) in the non-induced group and expressed NSE more strongly in the groups induced for 1 h, 3 h, 5 h and 8 h. NSE expression peaked at 5 h (P < 0.05), although there was no significant difference between 5 and 8 h (P > 0.05). Bcl-2 expression gradually decreased over time in the non-induced group (P < 0.05). However, Bax, caspase-9, Cyt-c and caspase-3 expression gradually increased and peaked at 8 h (P < 0.05). Transmission electron microscopy revealed karyopyknosis, chromatin edge setting, mitochondria swelling and cavitation in cells at 5 h, and the mitochondrial membrane potential decreased over time, as demonstrated by laser scanning confocal microscopy. After a 5 h induction, cells differentiated into typical neurons and expressed Bcl-2, which inhibited apoptosis. Bax showed a strong apoptosis-promoting capacity, leading to changes in the mitochondrial membrane potential and structure, and then triggered the caspase-independent apoptotic response through the mitochondrial pathway. At the same time, Cyt-c was directly or indirectly released from the mitochondria to the cytoplasm to trigger the caspase-dependent apoptotic response through the mitochondrial pathway. Therefore, Bcl-2/Bax play an important role in regulating caspase-dependent and caspase-independent apoptosis mediated by the mitochondrial pathway during the differentiation of ADSCs into neurons. PMID:27706181

  18. Involvement of proapoptotic Bcl-2 family members in terbinafine-induced mitochondrial dysfunction and apoptosis in HL60 cells.

    PubMed

    Yang, Kuo-Ching; Wu, Chi-Chen; Wu, Chih-Hsiung; Chen, Jur-Hao; Chu, Chien-Hwa; Chen, Chien-Ho; Chou, Yean-Hwei; Wang, Ying-Jan; Lee, Wen-Sen; Tseng, How; Lin, Shyr-Yi; Lee, Chia-Hwa; Ho, Yuan-Soon

    2006-02-01

    Terbinafine (TB, lamisil), a promising world widely used oral-anti-fungal agent, has been used in the treatment of superficial mycosis. In this study, we found that apoptosis but not cell growth arrest was induced by TB (1 microM, for 24 h) in human promyelocytic leukemia (HL60) cells. The apoptotic effect induced by TB in the HL60 cell was not through the general differentiation mechanisms evidenced by evaluation of three recognized markers, including CD11b, CD33, and morphological features. In addition, our results also revealed that TB-induced apoptosis was not through the cellular surface CD 95 receptor-mediated signaling pathway. We found that the mitochondria membrane in the TB-treated HL60 cells was dissipated by decreasing of the electrochemical gradient (DeltaPsi(m)) led to leakage of cytochrome c from mitochondria into cytosol. Such effects were completely blocked by in vitro transfection of the HL60 cells with Bcl-2 overexpression plasmid (HL60/Bcl-2). However, our data found that TB-mediated apoptosis could not be completely prevented in the Bcl-2 over expressed (HL60/Bcl-2) cells. Such results implied that additional mediators (such as caspase-9) other than mitochondria membrane permeability might contribute to the TB-induced cellular apoptosis signaling. This hypothesis was supported by the evidence that administration of caspases-9 specific inhibitor (z-LEHD-fmk) blocked the TB-induced apoptosis. Our studies highlight the molecular mechanisms of TB-induced apoptosis in human promyelocytic leukemia (HL60) cells.

  19. 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.

  20. 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.

  1. CacyBP/SIP enhances multidrug resistance of pancreatic cancer cells by regulation of P-gp and Bcl-2.

    PubMed

    Chen, Xiong; Zheng, Peichan; Xue, Zengfu; Li, Jie; Wang, Wenwu; Chen, Xi; Xie, Fangwei; Yu, Zongyang; Ouyang, Xuenong

    2013-07-01

    Our former report indicates that calcyclin-binding protein or Siah-1-interacting protein (CacyBP/SIP) is over-expressed in the SGC7901/ADR cell line. However, the potential role of CacyBP/SIP in the development of multidrug resistance (MDR) of pancreatic cancer is still uncertain. In this paper, we investigated the role of CacyBP/SIP in MDR of pancreatic cancer cells and its possible underlying mechanisms, and found that CacyBP/SIP was over-expressed in the Gemcitabine induced MDR pancreatic cancer cell PC-3/Gem compared with its parental cell PC-3. Up-regulation of CacyBP/SIP expression could enhance resistance of chemotherapy drugs on PC-3 cells and inhibit Adriamycin-induced apoptosis accompanied by decreased accumulation of intracellular Adriamycin. Furthermore, CacyBP/SIP could significantly up-regulate the expression of P-gp, Bcl-2, and the transcription of the MDR1 gene. In addition, the decrease of CacyBP/SIP expression using RNA interference or P-gp inhibitor could partially reverse CacyBP/SIP-mediated MDR. In brief, our study demonstrated that CacyBP/SIP could enhance the MDR phenotype of pancreatic cancer cells by increasing the expression of P-gp and Bcl-2, thus inhibiting apoptosis of pancreatic cancer cell.

  2. The BCL2 gene is regulated by a special AT-rich sequence binding protein 1-mediated long range chromosomal interaction between the promoter and the distal element located within the 3′-UTR

    PubMed Central

    Gong, Feiran; Sun, Luan; Wang, Zongdan; Shi, Junfeng; Li, Wei; Wang, Sumeng; Han, Xiao; Sun, Yujie

    2011-01-01

    The 279-bp major breakpoint region (mbr) within the 3′-untranslated region (3′-UTR) of the BCL2 gene is a binding site of special AT-rich sequence binding protein 1 (SATB1) that is well known to participate in the long-range regulation of gene transcription. Our previous studies have revealed that the mbr could regulate BCL2 transcription over a 200-kb distance and this regulatory function was closely related to SATB1. This study is to explore the underlying mechanism and its relevance to cellular apoptosis. With chromosome conformation capture (3C) and chromatin immunoprecipitation (ChIP) assays we demonstrated that the mbr could physically interact with BCL2 promoter through SATB1-mediated chromatin looping, which was required for epigenetic modifications of the promoter, CREB accessibility and high expression of the BCL2 gene. During early apoptosis, SATB1 was a key regulator of BCL2 expression. Inhibition of SATB1 cleavage by treatment of cells with a caspase-6 inhibitor or overexpression of mutant SATB1 that was resistant to caspase-6, inhibited disassembly of the SATB1-mediated chromatin loop and restored the BCL2 mRNA level in Jurkat cells. These data revealed a novel mechanism of BCL2 regulation and mechanistically link SATB1-mediated long-range interaction with the regulation of a gene controlling apoptosis pathway for the first time. PMID:21310710

  3. Inotodiol inhabits proliferation and induces apoptosis through modulating expression of cyclinE, p27, bcl-2, and bax in human cervical cancer HeLa cells.

    PubMed

    Zhao, Li-Wei; Zhong, Xiu-Hong; Yang, Shu-Yan; Zhang, Yi-Zhong; Yang, Ning-Jiang

    2014-01-01

    Inonotus obliquus is a medicinal mushroom that has been used as an effective agent to treat various diseases such as diabetes, tuberculosis and cancer. Inotodiol, an included triterpenoid shows significant anti-tumor effect. However, the mechanisms have not been well documented. In this study, we aimed to explore the effect of inotodiol on proliferation and apoptosis in human cervical cancer HeLa cells and investigated the underlying molecular mechanisms. HeLa cells were treated with different concentrations of inotodiol. The MTT assay was used to evaluate cell proliferating ability, flow cytometry (FCM) was employed for cell cycle analysis and cell apoptosis, while expression of cyclinE, p27, bcl-2 and bax was detected by immunocytochemistry. Proliferation of HeLa cells was inhibited by inotodiolin a dose-dependent manner at 24h (r=0.9999, p<0.01). A sub-G1 peak (apoptotic cells) of HeLa cells was detected after treatment and the apoptosis rate with the concentration and longer incubation time (r=1.0, p<0.01), while the percentage of cells in S phase and G2/M phase decreased significantly. Immunocytochemistry assay showed that the expression of cyclin E and bcl-2 in the treated cells significantly decreased, while the expression of p27 and bax obviously increased, compared with the control group (p<0.05). The results of our research indicate that inotodiol isolated from Inonotus obliquus inhibited the proliferation of HeLa cells and induced apoptosis in vitro. The mechanisms may be related to promoting apoptosis through increasing the expression of bax and cutting bcl-2 and affecting the cell cycle by down-regulation the expression of cyclin E and up-regulation of p27. The results further indicate the potential value of inotodiol for treatment of human cervical cancer.

  4. Recombinant human erythropoietin suppresses endothelial cell apoptosis and reduces the ratio of Bax to Bcl-2 proteins in the aortas of apolipoprotein E-deficient mice

    PubMed Central

    Warren, Jeffrey S.; Zhao, Ying; Yung, Raymond; Desai, Anjali

    2013-01-01

    Recent clinical trials have raised concern that therapy with recombinant human erythropoietin (EPO) may increase cardiovascular disease risk, event rate, and mortality. Endothelial cell (EC) apoptosis has been implicated in both atherogenesis as well as in the destabilization and rupture of atheromatous plaques. In the current study we observed that EPO and the EPO-mimetic peptide EMP-1 markedly suppressed lipopolysaccharide-induced apoptosis in EC monolayers. Therapeutic concentrations of EPO upregulated Bcl-2 expression while concurrently diminishing expression of Bax, resulting in a net decrease in the ratio of Bax to Bcl-2 protein concentrations. In vivo studies demonstrated that erythropoietin receptor (EPOR) is abundantly expressed in murine aorta and that EPO treatment for 10 weeks markedly decreased the ratio of Bax to Bcl-2 protein in the aortas of apolipoprotein E-deficient (APO E-KO) mice fed a high-fat diet. To our knowledge these data are the first to reveal a modulation of regulators of the apoptotic pathway in murine aorta by chronic EPO treatment. These observations imply that long-term administration of EPO may have the potential to affect plaque stability. PMID:21242808

  5. 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.

  6. The flavonoid morin from Moraceae induces apoptosis by modulation of Bcl-2 family members and Fas receptor in HCT 116 cells.

    PubMed

    Hyun, Hwang-Bo; Lee, Won Sup; Go, Se-Il; Nagappan, Arulkumar; Park, Cheol; Han, Min Ho; Hong, Su Hyun; Kim, Gonsup; Kim, Gi Young; Cheong, Jaehun; Ryu, Chung Ho; Shin, Sung Chul; Choi, Yung Hyun

    2015-01-01

    It is evident based on literature that flavonoids from fruit can safely modulate cancer cell biology and induce apoptosis. Therefore, we investigated the anticancer activity of morin, a flavonoid which is plentiful in twigs of mulberry focusing on apoptosis, and its mechanisms. Morin upregulated the Fas receptor, and activates caspase-8, -9 and -3 in HCT-116 cells. Morin also activates Bid, and induced the loss of mitochondrial membrane potential (MMP, ∆Ψm) with Bax protein activation and cytochrome c release. In addition, morin induced ROS generation which was not blocked by N-acetylcysteine. Morin also suppressed Bcl-2 and cIAP-1, anti-apoptotic proteins, which may contribute to augmentation of morin-triggered apoptosis. As an upstream signaling pathway, suppressed Akt activity by morin was associated to apoptosis. This study suggests that morin induces caspase-dependent apoptosis through extrinsic pathway by upregulating Fas receptor as well as through the intrinsic pathway by modulating Bcl-2 and IAP family members, and ROS generation, and that Akt is the critical upstream signaling that regulates the apoptotic effect of morin in human colon cancer HCT-116 cells.

  7. AS1411-Induced Growth Inhibition of Glioma Cells by Up-Regulation of p53 and Down-Regulation of Bcl-2 and Akt1 via Nucleolin

    PubMed Central

    Cheng, Ye; Zhao, Gang; Zhang, Siwen; Nigim, Fares; Zhou, Guangtong; Yu, Zhiyun; Song, Yang; Chen, Yong; Li, Yunqian

    2016-01-01

    AS1411 binds nucleolin (NCL) and is the first oligodeoxynucleotide aptamer to reach phase I and II clinical trials for the treatment of several cancers. However, the mechanisms by which AS1411 targets and kills glioma cells and tissues remain unclear. Here we report that AS1411 induces cell apoptosis and cycle arrest, and inhibits cell viability by up-regulation of p53 and down-regulation of Bcl-2 and Akt1 in human glioma cells. NCL was overexpressed in both nucleus and cytoplasm in human glioma U87, U251 and SHG44 cells compared to normal human astrocytes (NHA). AS1411 bound NCL and inhibited the proliferation of glioma cells but not NHA, which was accompanied with up-regulation of p53 and down-regulation of Bcl-2 and Akt1. Moreover, AS1411 treatment resulted in the G2/M cell cycle arrest in glioma cells, which was however abolished by overexpression of NCL. Further, AS1411 induced cell apoptosis, which was prevented by silencing of p53 and overexpression of Bcl-2. In addition, AS1411 inhibited the migration and invasion of glioma cells in an Akt1-dependent manner. Importantly, AS1411 inhibited the growth of glioma xenograft and prolonged the survival time of glioma tumor-bearing mice. These results revealed a promising treatment of glioma by oligodeoxynucleotide aptamer. PMID:27907160

  8. AS1411-Induced Growth Inhibition of Glioma Cells by Up-Regulation of p53 and Down-Regulation of Bcl-2 and Akt1 via Nucleolin.

    PubMed

    Cheng, Ye; Zhao, Gang; Zhang, Siwen; Nigim, Fares; Zhou, Guangtong; Yu, Zhiyun; Song, Yang; Chen, Yong; Li, Yunqian

    2016-01-01

    AS1411 binds nucleolin (NCL) and is the first oligodeoxynucleotide aptamer to reach phase I and II clinical trials for the treatment of several cancers. However, the mechanisms by which AS1411 targets and kills glioma cells and tissues remain unclear. Here we report that AS1411 induces cell apoptosis and cycle arrest, and inhibits cell viability by up-regulation of p53 and down-regulation of Bcl-2 and Akt1 in human glioma cells. NCL was overexpressed in both nucleus and cytoplasm in human glioma U87, U251 and SHG44 cells compared to normal human astrocytes (NHA). AS1411 bound NCL and inhibited the proliferation of glioma cells but not NHA, which was accompanied with up-regulation of p53 and down-regulation of Bcl-2 and Akt1. Moreover, AS1411 treatment resulted in the G2/M cell cycle arrest in glioma cells, which was however abolished by overexpression of NCL. Further, AS1411 induced cell apoptosis, which was prevented by silencing of p53 and overexpression of Bcl-2. In addition, AS1411 inhibited the migration and invasion of glioma cells in an Akt1-dependent manner. Importantly, AS1411 inhibited the growth of glioma xenograft and prolonged the survival time of glioma tumor-bearing mice. These results revealed a promising treatment of glioma by oligodeoxynucleotide aptamer.

  9. 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

  10. Repeated unpredictable stress and antidepressants differentially regulate expression of the bcl-2 family of apoptotic genes in rat cortical, hippocampal, and limbic brain structures.

    PubMed

    Kosten, Therese A; Galloway, Matthew P; Duman, Ronald S; Russell, David S; D'Sa, Carrol

    2008-06-01

    Apoptosis has been proposed as a contributing cellular mechanism to the structural alterations that have been observed in stress-related mood disorders. Antidepressants, on the other hand, are hypothesized to exert trophic and/or neuroprotective actions. The present study examined the regulation of the major antiapoptotic (Bcl-2, Bcl-xl) and proapoptotic (Bax) genes by repeated unpredictable stress (an animal model of depression) and antidepressant treatments (ADT). In adult rats, exposure to unpredictable stress reduced Bcl-2 mRNA levels in the central nucleus of the amygdala (CeA), cingulate (Cg), and frontal (Fr) cortices. Bcl-xl mRNA was significantly decreased in hippocampal subfields. In contrast, chronic administration of clinically effective antidepressants from four different classes, ie fluoxetine, reboxetine, tranylcypromine, and electroconvulsive seizures (ECS) upregulated Bcl-2 mRNA expression in the Cg, Fr, and CeA. Reboxetine, tranylcypromine, and ECS selectively increased Bcl-xl, but not Bcl-2 mRNA expression in the hippocampus. Chemical ADT but not ECS, robustly enhanced Bcl-2 expression in the medial amygdaloid nucleus and ventromedial hypothalamus. Fluoxetine did not influence Bcl-xl expression in the hippocampus, but it was the only ADT that decreased Bax expression in this region. In the CeA, again in direct contrast to the stress effects, exposure to all classes of ADTs significantly increased Bcl-2 mRNA. The selective regulation of Bcl-xl and Bax in hippocampal subfields and of Bcl-2 in the Cg cortex, amygdala, and hypothalamus suggests that these cellular adaptations contribute to the long-term neural plastic adaptations to stress and ADTs in cortical, hypothalamic, and limbic brain structures.

  11. Pinocembrin prevents glutamate-induced apoptosis in SH-SY5Y neuronal cells via decrease of bax/bcl-2 ratio.

    PubMed

    Gao, Mei; Zhang, Wen-Cui; Liu, Qing-Shan; Hu, Juan-Juan; Liu, Geng-Tao; Du, Guan-Hua

    2008-09-04

    Pinocembrin is the most abundant flavonoids in propolis, and has been proven to have antioxidant, antibacterial and anti-inflammatory property. To assess the protective effects of pinocembrin on neurons, SH-SY5Y neuronal cells were pretreated with pinocembrin for 2 h followed by co-treatment with glutamate (2 mM) for 12 h. Cell viability was determined by(3,4,5-dimethylthiazol-2-yl)-2,5-diphenylte-trazolium bromide assay, and apoptosis was confirmed by cell morphology, capillary zone electrophoresis and flow cytometry assay. Cell morphology was evaluated with Hoechst33258/PI dye. Treatment with pinocembrin (10(-5), 10(-6), 10(-7) mol/l) increased cell viability dose-dependently, inhibited LDH release and attenuated apoptosis. Intracellular free [Ca(2+)] was increased after glutamate exposure, and this increase was attenuated in cells treated with pinocembrin. bax mRNA expression increased remarkably following glutamate exposure and pinocembrin treatment manifested a reduction effect. bcl-2 mRNA expression changes were not detected in groups with or without pinocembrin. Western blotting results indicated that pinocembrin treatment reduced the expression of Bax and had no effect on Bcl-2, thus decreased the Bax-Bcl-2 ratio, which is in consistent with the gene expression result. Pinocembrin could also down-regulate the expression of p53 protein, and inhibit the release of cytochrome c from mitochondria to cytosol. Thus we conclude that pinocembrin exerts its neuroprotective effects in glutamate injury model partly by inhibiting p53 expression, thus Bax-Bcl-2 ratio, and the release of cytochrome c.

  12. 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.

  13. 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.

  14. Electromagnetic radiation at 900 MHz induces sperm apoptosis through bcl-2, bax and caspase-3 signaling pathways in rats.

    PubMed

    Liu, Qi; Si, Tianlei; Xu, Xiaoyun; Liang, Fuqiang; Wang, Lufeng; Pan, Siyi

    2015-08-04

    The decreased reproductive capacity of men is an important factor contributing to infertility. Accumulating evidence has shown that Electromagnetic radiation potentially has negative effects on human health. However, whether radio frequency electromagnetic radiation (RF-EMR) affects the human reproductive system still requires further investigation. Therefore, The present study investigates whether RF-EMR at a frequency of 900 MHz can trigger sperm cell apoptosis and affect semen morphology, concentration, and microstructure. Twenty four rats were exposed to 900 MHz electromagnetic radiation with a special absorption rate of 0.66 ± 0.01 W/kg for 2 h/d. After 50d, the sperm count, morphology, apoptosis, reactive oxygen species (ROS), and total antioxidant capacity (TAC), representing the sum of enzymatic and nonenzymatic antioxidants, were investigated. Western blotting and reverse transcriptase PCR were used to determine the expression levels of apoptosis-related proteins and genes, including bcl-2, bax, cytochrome c, and capase-3. In the present study, the percentage of apoptotic sperm cells in the exposure group was significantly increased by 91.42% compared with the control group. Moreover, the ROS concentration in exposure group was increased by 46.21%, while the TAC was decreased by 28.01%. Radiation also dramatically decreased the protein and mRNA expression of bcl-2 and increased that of bax, cytochrome c, and capase-3. RF-EMR increases the ROS level and decreases TAC in rat sperm. Excessive oxidative stress alters the expression levels of apoptosis-related genes and triggers sperm apoptosis through bcl-2, bax, cytochrome c and caspase-3 signaling pathways.

  15. BAD induces apoptosis in cells over-expressing Bcl-2 or Bcl-xL without loss of mitochondrial membrane potential.

    PubMed

    Schimmer, A D; Hedley, D W; Pham, N A; Chow, S; Minden, M D

    2001-07-01

    Inhibitors of Bcl-2 may be useful therapeutic agents for the treatment of a wide variety of malignancies including leukemia. A potential prototype of such a compound is the endogenous Bcl-2 and Bcl-xL binding protein BAD. Previous reports indicate that BAD can overcome the anti-apoptotic effect of Bcl-xL but not Bcl-2. If BAD cannot induce apoptosis in cells over-expressing Bcl-2, it would limit the application of molecules like BAD as novel anti-tumor agents. We report that transient transfection of BAD induced cell death in cells with and without over-expression of Bcl-2 or Bcl-xL. Forty-eight hours after transfection, BAD increased cell death in COS, COS Bcl-2, and COS Bcl-xL cells as demonstrated by decreased GFP expression, and an increase in the number of number of floating cells. In addition, BAD induced cell death in leukemic cell lines over-expressing Bcl-2 and Bcl-xL as determined by changes in luciferase activity. BAD-induced apoptosis was not accompanied by loss of mitochondrial membrane potential. Therefore, we conclude that transient transfection of BAD directly induces apoptosis in cells over-expressing Bcl-2 or Bcl-xL and validates the pursuit of molecules like BAD as novel therapeutic agents.

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

    PubMed

    Yang, Jiong; Yao, Shukun

    2015-10-27

    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.

  17. 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

  18. 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

  19. 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

  20. Characterization of apoptosis and autophagy through Bcl-2 and Beclin-1 immunoexpression in gestational trophoblastic disease.

    PubMed

    Wargasetia, Teresa Liliana; Shahib, Nurhalim; Martaadisoebrata, Djamhoer; Dhianawaty, Diah; Hernowo, Bethy

    2015-07-01

    The pathogenesis of Gestational Trophoblastic Disease (GTD) is not clearly known. 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. Bcl-2 and Beclin-1 immunoexpression were studied on complete hydatidiform mole, partial hydatidiform mole, invasive mole, choriocarcinoma and normal placenta slides. 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. 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.

  1. 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

  2. Oxindole alkaloids from Uncaria tomentosa induce apoptosis in proliferating, G0/G1-arrested and bcl-2-expressing acute lymphoblastic leukaemia cells.

    PubMed

    Bacher, Nicole; Tiefenthaler, Martin; Sturm, Sonja; Stuppner, Hermann; Ausserlechner, Michael J; Kofler, Reinhard; Konwalinka, Günther

    2006-03-01

    Natural products are still an untapped source of promising lead compounds for the generation of antineoplastic drugs. Here, we investigated for the first time the antiproliferative and apoptotic effects of highly purified oxindole alkaloids, namely isopteropodine (A1), pteropodine (A2), isomitraphylline (A3), uncarine F (A4) and mitraphylline (A5) obtained from Uncaria tomentosa, a South American Rubiaceae, on human lymphoblastic leukaemia T cells (CCRF-CEM-C7H2). Four of the five tested alkaloids inhibited proliferation of acute lymphoblastic leukaemia cells. Furthermore, the antiproliferative effect of the most potent alkaloids pteropodine (A2) and uncarine F (A4) correlated with induction of apoptosis. After 48 h, 100 micromol/l A2 or A4 increased apoptotic cells by 57%. CEM-C7H2 sublines with tetracycline-regulated expression of bcl-2, p16ink4A or constitutively expressing the cowpox virus protein crm-A were used for further studies of the apoptosis-inducing properties of these alkaloids. Neither overexpression of bcl-2 or crm-A nor cell-cycle arrest in G0/G1 phase by tetracycline-regulated expression of p16INK4A could prevent alkaloid-induced apoptosis. Our results show the strong apoptotic effects of pteropodine and uncarine F on acute leukaemic lymphoblasts and recommend the alkaloids for further studies in xenograft models.

  3. 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

    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

    2015-03-11

    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.

  4. 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

  5. Propofol-induced rno-miR-665 targets BCL2L1 and influences apoptosis in rodent developing hippocampal astrocytes.

    PubMed

    Sun, Wen-Chong; Liang, Zuo-Di; Pei, Ling

    2015-12-01

    Propofol exerts neurotoxic effects on the developing mammalian brains, but the underlying molecular mechanism remains unclear. MicroRNAs (miRNAs) are a class of small noncoding RNAs that modulate gene expression at the post-transcriptional level. However, in specific types of neurocytes, the detailed functions of miRNAs were not entirely understood. We investigated the potential role of miRNAs in astrocyte pathogenesis caused by propofol. We performed genome-wide microRNA expression profiling in immature cultured hippocampal astrocytes by microarray analysis and predicted their targets and functions using bioinformatics tools. The functional effects of one differentially expressed miRNA were examined experimentally in relation to astrocyte viability. The results showed that 13 miRNAs were significantly differentially expressed after both short-term exposure to high-concentration propofol (10 μg/ml for 1h) and long-term exposure to low-concentration propofol (0.9 μg/ml for 48 h), including rno-miR-665, differing significantly between the 2. Bioinformatics predicted putative binding sites for rno-miR-665 existing in the 3'-untranslated region of Bcl-2-like protein 1 BCL2L1 (Bcl-xl) mRNA. Moreover, such relationship was assessed by luciferase reporter assay, qRT-PCR and western blot. Rno-miR-665 which was significantly up-regulated by propofol can suppress BCL2L1 and elevate cleaved caspase-3 expression in immature astrocytes in vitro. Apoptosis of developing hippocampal astrocytes was thus significantly influenced by propofol or rno-miR-665, or both. Taken together, rno-miR-665 is involved in the neurotoxicity induced by propofol via a caspase-3 mediated mechanism by negatively regulating BCL2L1. It might act as an alternative therapeutic target for treatment of neurological disorders in peadiatric prolonged anesthesia or sedation with propofol clinically.

  6. 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

  7. Cytotoxic T lymphocytes promote cytarabine-induced acute myeloid leukemia cell apoptosis via inhibiting Bcl-2 expression

    PubMed Central

    Deng, Rui; Fan, Fang-Yi; Yi, Hai; Fu, Li; Zeng, Yan; Wang, Yi; Miao, Xiao-Juan; Shuai, Yan-Rong; He, Guang-Cui; Su, Yi

    2017-01-01

    Acute myeloid leukemia (AML) remains difficult to cure due to its drug tolerance and refractoriness. Immunotherapy is a growing area of cancer research, which has been applied for the treatment of numerous types of cancer, including leukemia. The present study generated AML cell-specific cytotoxic T lymphocytes (CTLs) in vitro and investigated the effect of combining CTL treatment with one of the most commonly used drugs for the treatment of hematological malignancies, cytarabine, on AML cell apoptosis. Firstly, it was observed that monocyte-depleted peripheral blood lymphocytes from healthy donors could be used to generate large numbers of CD3+CD8+ CTLs through immune stimulation. These CD3+CD8+ CTLs could effectively recognize and induce the apoptosis of human Kasumi-3 AML cells. In addition, cytarabine-induced AML cell apoptosis was enhanced by CTL treatment. Western blotting revealed that Bcl-2 expression was downregulated in AML cells following cytarabine and CTL treatment, indicating that the synergistic effect of this treatment on AML cell apoptosis is due to the downregulation of Bcl-2. These results highlight the potential application of CTL immunotherapy for the treatment of AML. Further studies optimizing the specificity and potency of CTLs, and identifying favorable combinations with other chemotherapeutic drug are required. PMID:28810561

  8. Cytotoxic T lymphocytes promote cytarabine-induced acute myeloid leukemia cell apoptosis via inhibiting Bcl-2 expression.

    PubMed

    Deng, Rui; Fan, Fang-Yi; Yi, Hai; Fu, Li; Zeng, Yan; Wang, Yi; Miao, Xiao-Juan; Shuai, Yan-Rong; He, Guang-Cui; Su, Yi

    2017-08-01

    Acute myeloid leukemia (AML) remains difficult to cure due to its drug tolerance and refractoriness. Immunotherapy is a growing area of cancer research, which has been applied for the treatment of numerous types of cancer, including leukemia. The present study generated AML cell-specific cytotoxic T lymphocytes (CTLs) in vitro and investigated the effect of combining CTL treatment with one of the most commonly used drugs for the treatment of hematological malignancies, cytarabine, on AML cell apoptosis. Firstly, it was observed that monocyte-depleted peripheral blood lymphocytes from healthy donors could be used to generate large numbers of CD3(+)CD8(+) CTLs through immune stimulation. These CD3(+)CD8(+) CTLs could effectively recognize and induce the apoptosis of human Kasumi-3 AML cells. In addition, cytarabine-induced AML cell apoptosis was enhanced by CTL treatment. Western blotting revealed that Bcl-2 expression was downregulated in AML cells following cytarabine and CTL treatment, indicating that the synergistic effect of this treatment on AML cell apoptosis is due to the downregulation of Bcl-2. These results highlight the potential application of CTL immunotherapy for the treatment of AML. Further studies optimizing the specificity and potency of CTLs, and identifying favorable combinations with other chemotherapeutic drug are required.

  9. Role of vitamins in determining apoptosis and extent of suppression by bcl-2 during hybridoma cell culture.

    PubMed

    Ishaque, A; Al-Rubeai, M

    2002-06-01

    The identification of cell culture media components that may instigate apoptosis in cell lines used for the production of commercial antibodies and recombinant proteins, is crucial to aid the development of improved media for reduced cell death and to understand the role of nutrient components in cell survival and maintenance. Here we determine the impact of depriving all or individual B-group media vitamins either, D-CaPantothenate (DCaP), choline chloride (CC), riboflavin (Rb), i-inositol, nicotinamide (NAM), pyridoxal hydrochloride (PyrHCl), folic acid (FA), or thiamine hydrochloride (ThHCl) on hybridoma cell growth and viability using fluorescence microscopy techniques. Cultivation in media deprived of all these vitamins prevented cell proliferation from reaching maximum capacity while increasing cell death rate, predominantly via apoptosis. Deletion of either DCaP, CC, or Rb showed that these components were most likely responsible for the development of apoptosis. Exclusion of either i-inositol, NAM or PyrHCl failed to inhibit cell growth and viability, while marginal improvements in viability were noted by ThHCl deprivation and more so by FA exclusion. Over-expression of the anti-apoptotic gene bcl-2 suppressed cell death initiated by all or single vitamin (either DCaP, CC or Rb) deprivation. The involvement of bcl-2 activity, established a close association between small vitamin molecules particularly DCaP, CC or Rb and the biochemical activation of apoptosis.

  10. MicroRNA-190b confers radio-sensitivity through negative regulation of Bcl-2 in gastric cancer cells.

    PubMed

    Wang, Changzheng; Qiao, Chuanhu

    2017-04-01

    To determine the role of miR-190b in radio-sensitivity of gastric cancer (GC). In radio-resistant GC cells, down-regulation of miR-190b and up-regulation of Bcl-2 were observed. The protein expression of Bcl-2 was negatively regulated by miR-190b. Overexpression of miR-190b significantly decreased cell viability and enhanced radio-sensitivity of GC cells. Of note, these effects of miR-190b on GC cells radio-sensitivity were abolished by Bcl-2. miR-190b confers radio-sensitivity of GC cells, possibly via negative regulation of Bcl-2.

  11. Differential Expression of Bcl-2 Family Proteins Determines the Sensitivity of Human Follicular Lymphoma Cells to Dexamethasone-mediated and Anti-BCR-mediated Apoptosis.

    PubMed

    Adem, Jemal; Ropponen, Antti; Eeva, Jonna; Eray, Mine; Nuutinen, Ulla; Pelkonen, Jukka

    2016-01-01

    Bcl-2 family comprises proapoptotic and antiapoptotic proteins. The balance between these proteins is critical for the survival of the cells. Overexpression of the antiapoptotic protein, Bcl-2, is the hallmark of follicular lymphoma (FL). High expression of Bcl-2 provides survival advantage and may facilitate chemotherapeutic resistance in FL. In the present study, we examined expression profile of Bcl-2 family proteins such as Bcl-2, Bcl-xL, and Bim in human FL cell lines, HF1A3 and HF28. We assessed the correlation between the expression levels of these proteins and cells' sensitivity to dexamethasone (Dex)-mediated and B-cell receptor (BCR)-mediated apoptosis. Here, we show that Dex and anti-BCR-induced synergistic apoptosis which correlated with significant downregulation of Bcl-xL, inhibition of ERK1/2 phosphorylation and accumulation of nonphosphorylated Bim. However, HF28 cells were less sensitive than HF1A3 cells to Dex-induced and anti-BCR-induced apoptosis due to high Bcl-2 protein level. It is interesting to note that, a Bcl-2-specific inhibitor, ABT-199, sensitized HF28 cells to Dex-induced or anti-BCR-induced apoptosis. In addition, overexpression of Bcl-xL prevented Dex-mediated, anti-BCR-mediated, and ABT-199-mediated apoptosis, indicating that mitochondria were involved. In conclusion, these data show that the expression levels of Bcl-2 family proteins may serve to predict tumor response to BH3 mimetics and the sensitivity of FL cells to Dex-induced and anti-BCR-induced apoptosis. Moreover, our results show that BCR-targeted apoptosis might have therapeutic benefit against FL and B-cell lymphomas.

  12. Effect of arsenic trioxide (ATO) on human lung carcinoma PG cell line: ATO induced apoptosis of PG cells and decreased expression of Bcl-2, Pgp.

    PubMed

    Han, Bo; Zhou, Gengyin; Zhang, Qinghui; Zhang, Jing; Wang, Xiaojuan; Tang, Weihua; Kakudo, Kennichi

    2004-12-01

    Arsenic trioxide (ATO) has been established to be an effective agent for treating newly diagnosed and relapsed acute promyelocytic leukemia (APL) patients. Laboratory data suggest that ATO induces apoptosis of hematopoietic or several solid tumor cells. However, to date, its effect on lung carcinoma has not been fully explored. In the present study, we investigated the effect of ATO on human lung carcinoma PG cells in vitro. We found ATO significantly inhibited the proliferation of PG cells in a dose- and time-dependent manner. ATO-induced apoptosis of PG cells was confirmed by the observance of typical morphological changes and detected by the analysis of flow cytometry (FCM). ATO significantly inhibited Bcl-2 and Pgp expression of PG cells by SABC immunohistochemistry and FCM analysis. In conclusion, our findings indicated that ATO induced apoptosis of PG cells and down-regulation of Bcl-2 and Pgp expressions, and these data might provide some theoretical basis for its clinical use in treating lung carcinoma.

  13. Placental apoptosis in preeclampsia, intrauterine growth retardation, and HELLP syndrome: an immunohistochemical study with caspase-3 and bcl-2.

    PubMed

    Cali, U; Cavkaytar, S; Sirvan, L; Danisman, N

    2013-01-01

    To examine the placental expression of caspase-3 and bcl-2 in pregnancies complicated by preeclampsia, IUGR, and HELLP syndrome. A prospective case-control study was conducted on 50 pregnant women between December 2006 and August 2007 at Dr. Zekai Tahir Burak Women Health Research and Education Hospital, Ankara, Turkey. Placental tissue samples were obtained from 15 pregnancies complicated by preeclampsia, 15 pregnancies with normotensive IUGR, five pregnancies with HELLP syndrome, and 15 gestational age-matched normotensive pregnancies without intrauterine infection as a control group. The placental expression of caspase-3 and bcl-2 has been investigated by immunohistochemical staining. Caspase-3 immunostaining score was significantly higher in each group when compared with the control group (p = 0.002). However there was no statistically signifant difference with bcl-2 immunostaining in each group when compared with the control group. Apoptotic marker caspase-3 is significantly increased in the villous trophoblasts of patients with preeclampsia, HELLP syndrome, and IUGR indicating increased placental apoptosis.

  14. Inhibition of oxygen-glucose deprivation-induced apoptosis of human adipose-derived stem cells by genetic modification with antiapoptotic protein bcl-2.

    PubMed

    Cui, Ziwei; Shen, Liangyun; Lin, Yue; Wang, Shuqin; Zheng, Dongfeng; Tan, Qian

    2014-08-01

    Adipose-derived stem cells (ADSCs) have become a promising tool for a wide range of cell-based therapies. However, transplanted ADSCs do not survive well under ischemic conditions. In this study we aimed to inhibit oxygen-glucose deprivation (OGD)-induced apoptosis of human ADSCs by genetic modification with antiapoptotic protein Bcl-2. After isolation and culture, the phenotypes of human ADSCs at passage 3 were analyzed by flow cytometry. Then, genetic modification of ADSCs with Bcl-2 was carried out. Bcl-2 gene transfection was verified by Western blot analysis and multipotent differentiation properties were evaluated in Bcl-2-modified ADSCs (Bcl-2-ADSCs). Apoptosis was evaluated by a TUNEL assay under ischemic conditions induced by OGD. Apoptotic nuclei were also assessed and quantified by Hoechst staining. The cultured ADSCs expressed stem cell-associated markers CD29, CD34, CD44, and CD90, but not fibroblast marker HLA-DR or hematopoietic stem cell marker CD133. The Bcl-2 gene was transferred into ADSCs efficiently, and Bcl-2-ADSCs differentiated into adipocytes, chondrocytes, and osteoblasts. In addition, Bcl-2 overexpression reduced the percentage of apoptotic Bcl-2-ADSCs by 38 % under OGD. Our results indicate that Bcl-2 overexpression through gene transfection inhibits apoptosis of ADSCs under ischemic conditions. This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

  15. Enhanced stability of Mcl1, a prosurvival Bcl2 relative, blunts stress-induced apoptosis, causes male sterility, and promotes tumorigenesis

    PubMed Central

    Okamoto, Toru; Coultas, Leigh; Metcalf, Donald; van Delft, Mark F.; Glaser, Stefan P.; Takiguchi, Megumi; Strasser, Andreas; Bouillet, Philippe; Adams, Jerry M.; Huang, David C. S.

    2014-01-01

    The B-cell CLL/lymphoma 2 (Bcl2) relative Myeloid cell leukemia sequence 1 (Mcl1) is essential for cell survival during development and for tissue homeostasis throughout life. Unlike Bcl2, Mcl1 turns over rapidly, but the physiological significance of its turnover has been unclear. We have gained insight into the roles of Mcl1 turnover in vivo by analyzing mice harboring a modified allele of Mcl1 that serendipitously proved to encode an abnormally stabilized form of Mcl1 due to a 13-aa N-terminal extension. Although the mice developed normally and appeared unremarkable, the homozygous males unexpectedly proved infertile due to defective spermatogenesis, which was evoked by enhanced Mcl1 prosurvival activity. Under unstressed conditions, the modified Mcl1 is present at levels comparable to the native protein, but it is markedly stabilized in cells subjected to stresses, such as protein synthesis inhibition or UV irradiation. Strikingly, the modified Mcl1 allele could genetically complement the loss of Bcl2, because introduction of even a single allele significantly ameliorated the severe polycystic kidney disease and consequent runting caused by Bcl2 loss. Significantly, the development of c-MYC–induced acute myeloid leukemia was also accelerated in mice harboring that Mcl1 allele. Our collective findings reveal that, under certain circumstances, the N terminus of Mcl1 regulates its degradation; that some cell types require degradation of Mcl1 to induce apoptosis; and, most importantly, that rapid turnover of Mcl1 can serve as a tumor-suppressive mechanism. PMID:24363325

  16. A computationally designed inhibitor of an Epstein-Barr viral Bcl-2 protein induces apoptosis in infected cells

    PubMed Central

    Shen, Betty W.; Song, Yifan; Frayo, Shani; Convertine, Anthony J.; Margineantu, Daciana; Booth, Garrett; Correia, Bruno E.; Cheng, Yuanhua; Schief, William R.; Hockenbery, David M.; Press, Oliver W.; Stoddard, Barry L.; Stayton, Patrick S.; Baker, David

    2014-01-01

    SUMMARY Since apoptosis of infected cells can limit virus production and spread, some viruses have co-opted prosurvival genes from the host. This includes the Epstein-Barr virus (EBV) gene BHRF1, a homologue of human Bcl-2 proteins that block apoptosis and are associated with cancer. Computational design and experimental optimization were used to generate a novel protein called BINDI that binds BHRF1 with picomolar affinity. BINDI recognizes the hydrophobic cleft of BHRF1 in a manner similar to other Bcl-2 protein interactions, but makes many additional contacts to achieve exceptional affinity and specificity. BINDI induces apoptosis in EBV-infected cancer lines, and when delivered with an antibody-targeted intracellular delivery carrier, BINDI suppressed tumor growth and extended survival in a xenograft disease model of EBV-positive human lymphoma. High specificity designed proteins that selectively kill target cells may provide an advantage over the toxic compounds used in current generation antibody-drug conjugates. PMID:24949974

  17. Spatiotemporal Expression of Bcl-2/Bax and Neural Cell Apoptosis in the Developing Lumbosacral Spinal Cord of Rat Fetuses with Anorectal Malformations.

    PubMed

    Yang, Zhonghua; Geng, Yuanyuan; Yao, Zhiya; Jia, Huimin; Bai, Yuzuo; Wang, Weilin

    2017-07-15

    Fecal incontinence and constipation still remain the major complications after procedures for anorectal malformations (ARMs). Previous studies have demonstrated a decrease of neural cell in lumbosacral spinal cord of ARMs patients and rat models. However, the underlying mechanism remains elusive. In this study, the neural cell apoptosis and Bcl-2/Bax expression were explored during lumbosacral spinal cord development in normal and ARMs fetuses. ARMs rat fetuses were induced by treating pregnant rats with ethylenethiourea on embryonic day 10. TUNEL staining was performed to identify apoptosis, and the expression of Bcl-2/Bax was confirmed with immunohistochemical staining, RT-qPCR and Western blot analysis on E16, E17, E19 and E21. Apoptosis index (AI) in the ARMs group was significantly higher compared to normal group. Our results showed that TUNEL-positive cells were mainly localized in the ventral horn, which is the location of neural cells controlling defecation. And the expression of Bcl-2 decreased, whereas the level of Bax increased in the ARMs fetuses. In addition, there was a significantly negative correlation between protein expression of Bcl-2/Bax ratio and AI in the ARMs group. Abnormal apoptosis might be a fundamental pathogenesis for the number decrease of neural cells in lumbosacral spinal cord, which leads to complications after procedures for ARMs. The negative correlation between the ratio of Bcl-2/Bax and AI manifested that Bcl-2/Bax pathway might be the mechanism for neural cell apoptosis in ARMs.

  18. 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.

  19. Inhibition of Bcl-2 antiapoptotic members by obatoclax potently enhances sorafenib-induced apoptosis in human myeloid leukemia cells through a Bim-dependent process.

    PubMed

    Rahmani, Mohamed; Aust, Mandy Mayo; Attkisson, Elisa; Williams, David C; Ferreira-Gonzalez, Andrea; Grant, Steven

    2012-06-21

    Interactions between the multikinase inhibitor sorafenib and the BH3-mimetic obatoclax (GX15-070) were examined in human acute myeloid leukemia (AML) cells. Treatment with sorafenib/obatoclax induced pronounced apoptosis in and reduced the clonogenic growth of multiple AML lines and primary AML cells but not normal CD34(+) cells. Sorafenib triggered rapid and pronounced Mcl-1 down-regulation accompanied by enhanced binding of Bim to Bcl-2 and Bcl-xL, effects that were abolished by obatoclax coadministration. Notably, shRNA knockdown of Bim, Bak, or Bax, but not Noxa, significantly attenuated obatoclax/sorafenib lethality, whereas ectopic expression of Mcl-1 exerted a protective effect. Furthermore, exposure of leukemia cells to sorafenib and obatoclax markedly induced autophagy, reflected by rapid and pronounced LC3 processing and LC3-green fluorescent protein (GFP) punctate formation. Multiple autophagy inhibitors or VPS34 knockdown, significantly potentiated sorafenib/obatoclax lethality, indicating a cytoprotective role for autophagy in this setting. Finally, studies in a xenograft mouse model revealed that combined sorafenib/obatoclax treatment markedly reduced tumor growth and significantly prolonged survival in association with Mcl-1 down-regulation and apoptosis induction, whereas agents administered individually had only modest effects. These findings suggest that combining sorafenib with agents that inhibit Mcl-1 and Bcl-2/Bcl-xL such as obatoclax may represent a novel and potentially effective strategy in AML.

  20. Inhibition of Bcl-2 antiapoptotic members by obatoclax potently enhances sorafenib-induced apoptosis in human myeloid leukemia cells through a Bim-dependent process

    PubMed Central

    Aust, Mandy Mayo; Attkisson, Elisa; Williams, David C.; Ferreira-Gonzalez, Andrea

    2012-01-01

    Interactions between the multikinase inhibitor sorafenib and the BH3-mimetic obatoclax (GX15-070) were examined in human acute myeloid leukemia (AML) cells. Treatment with sorafenib/obatoclax induced pronounced apoptosis in and reduced the clonogenic growth of multiple AML lines and primary AML cells but not normal CD34+ cells. Sorafenib triggered rapid and pronounced Mcl-1 down-regulation accompanied by enhanced binding of Bim to Bcl-2 and Bcl-xL, effects that were abolished by obatoclax coadministration. Notably, shRNA knockdown of Bim, Bak, or Bax, but not Noxa, significantly attenuated obatoclax/sorafenib lethality, whereas ectopic expression of Mcl-1 exerted a protective effect. Furthermore, exposure of leukemia cells to sorafenib and obatoclax markedly induced autophagy, reflected by rapid and pronounced LC3 processing and LC3–green fluorescent protein (GFP) punctate formation. Multiple autophagy inhibitors or VPS34 knockdown, significantly potentiated sorafenib/obatoclax lethality, indicating a cytoprotective role for autophagy in this setting. Finally, studies in a xenograft mouse model revealed that combined sorafenib/obatoclax treatment markedly reduced tumor growth and significantly prolonged survival in association with Mcl-1 down-regulation and apoptosis induction, whereas agents administered individually had only modest effects. These findings suggest that combining sorafenib with agents that inhibit Mcl-1 and Bcl-2/Bcl-xL such as obatoclax may represent a novel and potentially effective strategy in AML. PMID:22446485

  1. Bcl-2 inhibitors sensitize tumor necrosis factor-related apoptosis-inducing ligand-induced apoptosis by uncoupling of mitochondrial respiration in human leukemic CEM cells.

    PubMed

    Hao, Ji-Hui; Yu, Ming; Liu, Feng-Ting; Newland, Adrian C; Jia, Li

    2004-05-15

    Previous studies have shown that the lymphoblastic leukemia CEM cell line is resistant to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis because of a low expression of caspase-8. Bcl-2 inhibitors, BH3I-2' and HA14-1, are small cell-permeable nonpeptide compounds, are able to induce apoptosis by mediating cytochrome c release, and also lead to dissipation of the mitochondrial membrane potential (DeltaPsim). This study aimed to use the Bcl-2 inhibitors to sensitize CEM cells to TRAIL-induced apoptosis by switching on the mitochondrial apoptotic pathway. We found that a low dose of BH3I-2' or HA14-1, which did not induce cytochrome c release, greatly sensitized CEM cells to TRAIL-induced apoptosis. In a similar manner to the classical uncoupler carbonyl cyanide m-chlorophenylhydrazone (CCCP), both BH3I-2' and HA14-1 induced a reduction in DeltaPsim, a generation of reactive oxygen species (ROS), an increased mitochondrial respiration, and a decreased ATP synthesis. This uncoupling function of the Bcl-2 inhibitors was responsible for the synergy with TRAIL-induced apoptosis. CCCP per se did not induce apoptosis but again sensitized CEM cells to TRAIL-induced apoptosis by uncoupling mitochondrial respiration. The uncoupling effect facilitated TRAIL-induced Bax conformational change and cytochrome c release from mitochondria. Inhibition of caspases failed to block TRAIL-mediated cell death when mitochondrial respiration was uncoupled. We observed that BH3I-2', HA14-1, or CCCP can overcome resistance to TRAIL-induced apoptosis in TRAIL-resistant cell lines, such as CEM, HL-60, and U937. Our results suggest that the uncoupling of mitochondrial respiration can sensitize leukemic cells to TRAIL-induced apoptosis. However, caspase activation per se does not represent an irreversible point of commitment to TRAIL-induced cell death when mitochondrial respiration is uncoupled.

  2. 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

  3. Hyperoside induces apoptosis and inhibits growth in pancreatic cancer via Bcl-2 family and NF-κB signaling pathway both in vitro and in vivo.

    PubMed

    Li, Yilong; Wang, Yongwei; Li, Le; Kong, Rui; Pan, Shangha; Ji, Liang; Liu, Huan; Chen, Hua; Sun, Bei

    2016-06-01

    Although advanced surgical operation and chemotherapy have been under taken, pancreatic cancer remains one of the most aggressive and fatal human malignancies with a low 5-year survival rate of less than 5 %. Therefore, novel therapeutic strategies for prevention and remedy are urgently needed in pancreatic cancer. This present research aimed to investigate the anti-cancer effects of hyperoside in human pancreatic cancer cells. Our in vitro results showed that hyperoside suppressed the proliferation and promoted apoptosis of two different human pancreatic cancer cell lines, which correlated with up-regulation of the ratios of Bax/Bcl-2 and Bcl-xL and down-regulation of levels of nuclear factor-κB (NF-κB) and NF-κB's downstream gene products. What's more, using an orthotopic model of human pancreatic cancer, we found that hyperoside also inhibited the tumor growth significantly. Mechanically, these outcomes could also be associated with the up-regulation of the ratios of Bax/Bcl-2 and Bcl-xL and down-regulation of levels of NF-κB and NF-κB's downstream gene products. Collectively, our experiments indicate that hyperoside may be a promising candidate agent for the treatment of pancreatic cancer.

  4. [Effect of small interfering RNA targeting multidrug resistance-related protein and bcl-2 on drug resistance and apoptosis of K562 and K562/ADM cells].

    PubMed

    Song, Zhao-yang; Hu, Hai-yan; Deng, Lan; Wu, Bing-yi; Guo, Kun-yuan; Zhang, Mei-xia

    2008-07-01

    To observe the effect of small interfering RNA (siRNA) targeting multidrug resistance-related protein (MRP) and bcl-2 genes in modulating drug resistance and apoptosis of K562 and K562/ADM cells. Two siRNA constructs targeting respectively bcl-2 and MRP genes, were synthesized and transfected either alone or in combination into K562 and K562/ADM cells via lipofectamine2000. MTT assay was used to evaluate the viability of the transfected cells at 24, 48 and 72 h Post-fransfection, and RT-PCR was performed to determine the mRNA levels of bcl-2 and MRP. The effects of MRP siRNA and bcl2 siRNA on the apoptosis and the protein expression of Bcl-2 and MRP were evaluated with flow cytometry. In K562/ADM cells, the IC (50) decreased from 12.81 microg/ml (ADM group) to 3.74 microg/ml (ADM+MRP siRNA group), 6.82 microg/ml (ADM+bcl2 siRNA group) and 2.51 microg/ml (ADM+MRP siRNA+bcl2 siRNA). Similarly, in K562 cells, the IC50 decreased significantly from 6.75 microg/ml (ADM) to 3.22 microg/ml (ADM+MRP siRNA), 3.56 microg/ml (ADM+bcl2 siRNA) and 1.84 microg/ml (ADM+MRP siRNA+bcl2 siRNA) (P<0.05). Flow cytometry demonstrated significantly increased apoptosis of the cells following MRP siRNA and bcl2 siRNA transfection, which also resulted in significantly decreased expressions of MRP and bcl-2 proteins (P<0.05). Treatment with both MRP and bcl-2 siRNAs inhibits the target gene expression, and increases the drug sensitivity and apoptosis of K562 and K562/ADM cells.

  5. Hydroxyl radical mediates cisplatin-induced apoptosis in human hair follicle dermal papilla cells and keratinocytes through Bcl-2-dependent mechanism.

    PubMed

    Luanpitpong, Sudjit; Nimmannit, Ubonthip; Chanvorachote, Pithi; Leonard, Stephen S; Pongrakhananon, Varisa; Wang, Liying; Rojanasakul, Yon

    2011-08-01

    Induction of massive apoptosis of hair follicle cells by chemotherapy has been implicated in the pathogenesis of chemotherapy-induced alopecia (CIA), but the underlying mechanisms of regulation are not well understood. The present study investigated the apoptotic effect of cisplatin in human hair follicle dermal papilla cells and HaCaT keratinocytes, and determined the identity and role of specific reactive oxygen species (ROS) involved in the process. Treatment of the cells with cisplatin induced ROS generation and a parallel increase in caspase activation and apoptotic cell death. Inhibition of ROS generation by antioxidants inhibited the apoptotic effect of cisplatin, indicating the role of ROS in the process. Studies using specific ROS scavengers further showed that hydroxyl radical, but not hydrogen peroxide or superoxide anion, is the primary oxidative species responsible for the apoptotic effect of cisplatin. Electron spin resonance studies confirmed the formation of hydroxyl radicals induced by cisplatin. The mechanism by which hydroxyl radical mediates the apoptotic effect of cisplatin was shown to involve down-regulation of the anti-apoptotic protein Bcl-2 through ubiquitin-proteasomal degradation. Bcl-2 was also shown to have a negative regulatory role on hydroxyl radical. Together, our results indicate an essential role of hydroxyl radical in cisplatin-induced cell death of hair follicle cells through Bcl-2 regulation. Since CIA is a major side effect of cisplatin and many other chemotherapeutic agents with no known effective treatments, the knowledge gained from this study could be useful in the design of preventive treatment strategies for CIA through localized therapy without compromising the chemotherapy efficacy.

  6. 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

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

    PubMed

    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

    2017-01-10

    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.

  8. Canonical Bcl-2 motifs of the Na+/K+ pump revealed by the BH3 mimetic chelerythrine: early signal transducers of apoptosis?

    PubMed

    Lauf, Peter K; Heiny, Judith; Meller, Jarek; Lepera, Michael A; Koikov, Leonid; Alter, Gerald M; Brown, Thomas L; Adragna, Norma C

    2013-01-01

    Chelerythrine [CET], a protein kinase C [PKC] inhibitor, is a prop-apoptotic BH3-mimetic binding to BH1-like motifs of Bcl-2 proteins. CET action was examined on PKC phosphorylation-dependent membrane transporters (Na+/K+ pump/ATPase [NKP, NKA], Na+-K+-2Cl+ [NKCC] and K+-Cl- [KCC] cotransporters, and channel-supported K+ loss) in human lens epithelial cells [LECs]. K+ loss and K+ uptake, using Rb+ as congener, were measured by atomic absorption/emission spectrophotometry with NKP and NKCC inhibitors, and Cl- replacement by NO3ˉ to determine KCC. 3H-Ouabain binding was performed on a pig renal NKA in the presence and absence of CET. Bcl-2 protein and NKA sequences were aligned and motifs identified and mapped using PROSITE in conjunction with BLAST alignments and analysis of conservation and structural similarity based on prediction of secondary and crystal structures. CET inhibited NKP and NKCC by >90% (IC50 values ~35 and ~15 μM, respectively) without significant KCC activity change, and stimulated K+ loss by ~35% at 10-30 μM. Neither ATP levels nor phosphorylation of the NKA α1 subunit changed. 3H-ouabain was displaced from pig renal NKA only at 100 fold higher CET concentrations than the ligand. Sequence alignments of NKA with BH1- and BH3-like motifs containing pro-survival Bcl-2 and BclXl proteins showed more than one BH1-like motif within NKA for interaction with CET or with BH3 motifs. One NKA BH1-like motif (ARAAEILARDGPN) was also found in all P-type ATPases. Also, NKA possessed a second motif similar to that near the BH3 region of Bcl-2. Findings support the hypothesis that CET inhibits NKP by binding to BH1-like motifs and disrupting the α1 subunit catalytic activity through conformational changes. By interacting with Bcl-2 proteins through their complementary BH1- or BH3-like-motifs, NKP proteins may be sensors of normal and pathological cell functions, becoming important yet unrecognized signal transducers in the initial phases of apoptosis. CET

  9. Protooncogene bcl-2 gene transfer abrogates Fas/APO-1 antibody-mediated apoptosis of human malignant glioma cells and confers resistance to chemotherapeutic drugs and therapeutic irradiation.

    PubMed Central

    Weller, M; Malipiero, U; Aguzzi, A; Reed, J C; Fontana, A

    1995-01-01

    The majority of human malignant glioma cells express Fas/APO-1 and are susceptible to Fas/APO-1 antibody-mediated apoptosis in vitro. The sensitivity of Fas/APO-1-positive glioma cell lines to Fas/APO-1 antibody-mediated killing correlates inversely with the constitutive expression of the antiapoptotic protooncogene bcl-2. Here we report that BCL-2 protein expression of human glial tumors in vivo correlates with malignant transformation in that BCL-2 immunoreactive glioma cells were more abundant in WHO grade III/IV gliomas than in grade I/II gliomas. Fas/APO-1 antibody-sensitive human glioma cell lines stably transfected with a murine bcl-2 cDNA acquired resistance to Fas/APO-1 antibody-mediated apoptosis. Forced expression of bcl-2 also attenuated TNF alpha-mediated cytotoxicity of glioma cell lines in the presence of actinomycin D and cycloheximide and conferred partial protection from irradiation and the cancer chemotherapy drugs, cisplatin and BCNU. Preexposure of the glioma cell lines to the cytokines, IFN gamma and TNF alpha, which sensitize for Fas/APO-1-dependent killing, partially overcame bcl-2-mediated rescue from apoptosis, suggesting that multimodality immunotherapy involving cytokines and Fas/APO-1 targeting might eventually provide a promising approach to the treatment of human malignant gliomas. Images PMID:7539458

  10. 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.

  11. Structural Basis for Bcl-2-Regulated Mitochondrion-Dependent Apoptosis

    DTIC Science & Technology

    2004-04-01

    rates are useful for identifying Sresidues that are involved in hydrogen bonding and that are zexposed to water. The amide hydrogens in trans-membrane...34. - helices can have very slow exchange rates due to their strong0 hydrogen bonds in the low dielectric of the lipid bilayer envi-250 200 150 100 50 0...toward the N terminus and into the peptide planes resulted in 16 possible conformations for the lipid-water interface, where it can hydrogen - bond with ei

  12. 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

  13. Bcl-2–dependent oxidation of pyruvate dehydrogenase-E2, a primary biliary cirrhosis autoantigen, during apoptosis

    PubMed Central

    Odin, Joseph A.; Huebert, Robert C.; Casciola-Rosen, Livia; LaRusso, Nicholas F.; Rosen, Antony

    2001-01-01

    The close association between autoantibodies against pyruvate dehydrogenase-E2 (PDC-E2), a ubiquitous mitochondrial protein, and primary biliary cirrhosis (PBC) is unexplained. Many autoantigens are selectively modified during apoptosis, which has focused attention on apoptotic cells as a potential source of “neo-antigens” responsible for activating autoreactive lymphocytes. Since increased apoptosis of bile duct epithelial cells (cholangiocytes) is evident in patients with PBC, we evaluated the effect of apoptosis on PDC-E2. Autoantibody recognition of PDC-E2 by immunofluorescence persisted in apoptotic cholangiocytes and appeared unchanged by immunoblot analysis. PDC-E2 was neither cleaved by caspases nor concentrated into surface blebs in apoptotic cells. In other cell types, autoantibody recognition of PDC-E2, as assessed by immunofluorescence, was abrogated after apoptosis, although expression levels of PDC-E2 appeared unchanged when examined by immunoblot analysis. Both overexpression of Bcl-2 and depletion of glutathione before inducing apoptosis prevented this loss of autoantibody recognition, suggesting that glutathiolation, rather than degradation or loss, of PDC-E2 was responsible for the loss of immunofluorescence signal. We postulate that apoptotic cholangiocytes, unlike other apoptotic cell types, are a potential source of immunogenic PDC-E2 in patients with PBC. PMID:11457875

  14. Overexpression of Endogenous Anti-Oxidants with Selenium Supplementation Protects Trophoblast Cells from Reactive Oxygen Species-Induced Apoptosis in a Bcl-2-Dependent Manner.

    PubMed

    Khera, Alisha; Vanderlelie, Jessica J; Holland, Olivia; Perkins, Anthony V

    2017-06-01

    The human placenta provides life support for the developing foetus, and a healthy placenta is a prerequisite to a healthy start to life. Placental tissue is subject to oxidative stress which can lead to pathological conditions of pregnancy such as preeclampsia, preterm labour and intrauterine growth restriction. Up-regulation of endogenous anti-oxidants may alleviate placental oxidative stress and provide a therapy for these complications of pregnancy. In this study, selenium supplementation, as inorganic sodium selenite (NaSel) or organic selenomethionine (SeMet), was used to increase the protein production and cellular activity of the important redox active proteins glutathione peroxidase (GPx) and thioredoxin reductase (Thx-Red). Placental trophoblast cell lines, BeWo, JEG-3 and Swan-71, were cultured in various concentrations of NaSel or SeMet for 24 h and cell extracts prepared for western blots and enzyme assays. Rotenone and antimycin were used to stimulate mitochondrial reactive oxygen species (ROS) production and induce apoptosis. Trophoblast cells supplemented with 100 nM NaSel and 500 nM SeMet exhibited significantly enhanced expression and activity of both GPx and Thx-Red. Antimycin and rotenone were found to generate ROS when measured by 2',7'-dichlorofluorescein diacetate (DCFDA) assay, and selenium supplementation was shown to reduce ROS production in a dose-dependent manner. Rotenone, 100 μM treatment for 4 h, caused trophoblast cell apoptosis as evidenced by increased Annexin V binding and decreased expression of Bcl-2. In both assays of apoptosis, selenium supplementation was able to prevent apoptosis, preserve Bcl-2 expression and protect trophoblast cells from mitochondrial oxidative stress. This data suggests that selenoproteins such as GPx and Thx-Red have an important role in protecting trophoblast cells from mitochondrial oxidative stress and that selenium supplementation may be important in treating some placental pathologies.

  15. 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

  16. 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

  17. Structural Mechanism for Regulation of Bcl-2 protein Noxa by phosphorylation

    NASA Astrophysics Data System (ADS)

    Karim, Christine B.; Michel Espinoza-Fonseca, L.; James, Zachary M.; Hanse, Eric A.; Gaynes, Jeffrey S.; Thomas, David D.; Kelekar, Ameeta

    2015-09-01

    We showed previously that phosphorylation of Noxa, a 54-residue Bcl-2 protein, at serine 13 (Ser13) inhibited its ability to promote apoptosis through interactions with canonical binding partner, Mcl-1. Using EPR spectroscopy, molecular dynamics (MD) simulations and binding assays, we offer evidence that a structural alteration caused by phosphorylation partially masks Noxa’s BH3 domain, inhibiting the Noxa-Mcl-1 interaction. EPR of unphosphorylated Noxa, with spin-labeled amino acid TOAC incorporated within the BH3 domain, revealed equilibrium between ordered and dynamically disordered states. Mcl-1 further restricted the ordered component for non-phosphorylated Noxa, but left the pSer13 Noxa profile unchanged. Microsecond MD simulations indicated that the BH3 domain of unphosphorylated Noxa is housed within a flexible loop connecting two antiparallel β-sheets, flanked by disordered N- and C-termini and Ser13 phosphorylation creates a network of salt-bridges that facilitate the interaction between the N-terminus and the BH3 domain. EPR showed that a spin label inserted near the N-terminus was weakly immobilized in unphosphorylated Noxa, consistent with a solvent-exposed helix/loop, but strongly constrained in pSer13 Noxa, indicating a more ordered peptide backbone, as predicted by MD simulations. Together these studies reveal a novel mechanism by which phosphorylation of a distal serine inhibits a pro-apoptotic BH3 domain and promotes cell survival.

  18. Apigenin induces apoptosis via tumor necrosis factor receptor- and Bcl-2-mediated pathway and enhances susceptibility of head and neck squamous cell carcinoma to 5-fluorouracil and cisplatin.

    PubMed

    Chan, Leong-Perng; Chou, Tzung-Han; Ding, Hsiou-Yu; Chen, Pin-Ru; Chiang, Feng-Yu; Kuo, Po-Lin; Liang, Chia-Hua

    2012-07-01

    Apigenin, a natural plant flavone, may have chemopreventive and therapeutic potentials for anti-inflammatory, antioxidant, and anti-cancer. Nevertheless, the anti-tumor effect of apigenin on human head and neck squamous cell carcinoma (HNSCC) is not fully understood. The antioxidant capacity and protective effects of apigenin against oxidative stress in murine normal embryonic liver BNLCL2 cells are examined. Cell viability, morphologic change, clonogenic survival, cell cycle distribution, reactive oxygen species (ROS) production, glutathione formation, and death receptors- and Bcl-2-mediated caspase pathways of HNSCC SCC25 cells and A431 cells with apigenin are investigated. Apigenin inhibits the growth of SCC25 and A431 cells and induces cell cycle arrest in the G2/M phase. Apigenin has an antioxidant capacity as well as the ability to inhibit lipid peroxidation. It protects BNLCL2 cells against oxidative damage, and is potentially able to prevent cancer. Apigenin increases intracellular ROS levels and reduces levels of glutathione; it also induces cell apoptosis via tumor necrosis factor receptor (TNF-R)-, TNF-related apoptosis-inducing ligand receptor (TRAIL-R)-, and Bcl-2-mediated caspase-dependent cell death pathways in SCC25 cells. The combination of apigenin with 5-fluorouracil (5-Fu) or cisplatin induces the dramatic death of SCC25 cells. Apigenin induces SCC25 cell apoptosis via the up-regulation of both TNF-R and TRAIL-R signaling pathways, and has a synergistic effect on the inhibition of cell proliferation in combination with 5-Fu or cisplatin. These analytical findings suggest that apigenin may be a good therapeutic agent against HNSCC cells. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. Regulation of cell division cycle progression by bcl-2 expression: a potential mechanism for inhibition of programmed cell death

    PubMed Central

    1996-01-01

    Expression of the bcl-2 gene has been shown to effectively confer resistance to programmed cell death under a variety of circumstances. However, despite a wealth of literature describing this phenomenon, very little is known about the mechanism of resistance. In the experiments described here, we show that bcl-2 gene expression can result in an inhibition of cell division cycle progression. These findings are based upon the analysis of cell cycle distribution, cell cycle kinetics, and relative phosphorylation of the retinoblastoma tumor suppressor protein, using primary tissues in vivo, ex vivo, and in vitro, as well as continuous cell lines. The effects of bcl-2 expression on cell cycle progression appear to be focused at the G1 to S phase transition, which is a critical control point in the decision between continued cell cycle progression or the induction programmed cell death. In all systems tested, bcl-2 expression resulted in a substantial 30-60% increase in the length of G1 phase; such an increase is very substantial in the context of other regulators of cell cycle progression. Based upon our findings, and the related findings of others, we propose a mechanism by which bcl-2 expression might exert its well known inhibition of programmed cell death by regulating the kinetics of cell cycle progression at a critical control point. PMID:8642331

  20. 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

  1. 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.

  2. [Effect of leptin on expression of calpain-1 and Bcl-2 and apoptosis in myocardial tissue of neonatal rats after asphyxia].

    PubMed

    Wu, Dan-Dan; Wu, Xing-Heng; Zhang, Li-Na

    2016-10-01

    To study the effect of leptin on the expression of calcium-activated neutral protease 1 (calpain-1) and B cell lymphoma-2 (Bcl-2) and apoptosis in the myocardial tissue of neonatal rats after asphyxia. A total of 48 neonatal rats were randomly and equally divided into normal control group, asphyxia group, leptin treatment groups, and calpain-1 inhibitor (CAI-1) group. The neonatal rat model of asphyxia under normal atmospheric condition was established in all groups except the control group. For the leptin treatment groups, rats received 20, 80, and 160 μg/kg leptin by intraperitoneal injection immediately after model establishment, respectively. For the CAI-1 group, rats received 10 mg/kg CAI-1 by intraperitoneal injection immediately after model establishment. For all the groups, the myocardial tissue was collected at 2 hours after model establishment. Immunohistochemistry was used to measure the expression of calpain-1 and Bcl-2. The TUNEL method was used to evaluate apoptosis of myocardial cells. The expression of calpain-1 and Bcl-2 and apoptosis index (AI) were significantly higher in the asphyxia group than in the normal control group (P˂0.05). The leptin treatment groups and the CAI-1 group had significantly lower expression of calpain-1, significantly lower AI, and significantly higher expression of Bcl-2 than the asphyxia group (P˂0.05). The CAI-1 group had the largest changes in all the indices compared with the asphyxia group. However, there were no significant differences in all indices between the 160 μg/kg leptin treatment group and the CAI-1 group. After asphyxia, the expression of calpain-1 was positively correlated with AI, while the expression of Bcl-2 was negatively correlated with AI and the expression of calpain-1 (P˂0.05). Leptin reduces apoptosis of myocardial cells in asphyxiated neonatal rats by the inhibition of calpain-1 activation and upregulation of Bcl-2 expression.

  3. The distinct role of guanine nucleotide exchange factor Vav1 in Bcl-2 transcription and apoptosis inhibition in Jurkat leukemia T cells

    PubMed Central

    Yin, Jie; Wan, Ya-juan; Li, Shi-yang; Du, Ming-juan; Zhang, Cui-zhu; Zhou, Xing-long; Cao, You-jia

    2011-01-01

    Aim: To investigate a novel function of proto-oncogene Vav1 in the apoptosis of human leukemia Jurkat cells. Methods: Jurkat cells, Jurkat-derived vav1-null cells (J.Vav1) and Vav1-reconstituted J.WT cells were treated with a Fas agonist antibody, IgM clone CH11. Apoptosis was determined using propidium iodide (PI) staining, Annexin-V staining, DNA fragmentation, cleavage of caspase 3/caspase 8, and poly (ADP-ribose) polymerase (PARP). Mitochondria transmembrane potential (ΔΨm) was measured using DiOC6(3) staining. Transcription and expression of the Bcl-2 family of proteins were evaluated using semi-quantitative RT-PCR and Western blot, respectively. Bcl-2 promoter activity was analyzed using luciferase reporter assays. Results: Cells lacking Vav1 were more sensitive to Fas-mediated apoptosis than Jurkat and J.WT cells. J.Vav1 cells lost mitochondria transmembrane potential (ΔΨm) more rapidly upon Fas induction. These phenotypes could be rescued by re-expression of Vav1 in J.Vav1 cells. The expression of Vav1 increased the transcription of pro-survival Bcl-2. The guanine nucleotide exchange activity of Vav1 was required for enhancing Bcl-2 promoter activity, and the Vav1 downstream substrate, small GTPase Rac2, was likely involved in the control of Bcl-2 expression. Conclusion: Vav1 protects Jurkat cells from Fas-mediated apoptosis by promoting Bcl-2 transcription through its GEF activity. PMID:21151158

  4. BCL-2 Modifying Factor (BMF) Is a Central Regulator of Anoikis in Human Intestinal Epithelial Cells*

    PubMed Central

    Hausmann, Martin; Leucht, Katharina; Ploner, Christian; Kiessling, Stephan; Villunger, Andreas; Becker, Helen; Hofmann, Claudia; Falk, Werner; Krebs, Michaela; Kellermeier, Silvia; Fried, Michael; Schölmerich, Jürgen; Obermeier, Florian; Rogler, Gerhard

    2011-01-01

    BCL-2 modifying factor (BMF) is a sentinel considered to register damage at the cytoskeleton and to convey a death signal to B-cell lymphoma 2. B-cell lymphoma 2 is neutralized by BMF and thereby facilitates cytochrome C release from mitochondria. We investigated the role of BMF for intestinal epithelial cell (IEC) homeostasis. Acute colitis was induced in Bmf-deficient mice (Bmf−/−) with dextran sulfate sodium. Colonic crypt length in Bmf−/− mice was significantly increased as compared with WT mice. Dextran sulfate sodium induced less signs of colitis in Bmf−/− mice, as weight loss was reduced compared with the WT. Primary human IEC exhibited increased BMF in the extrusion zone. Quantitative PCR showed a significant up-regulation of BMF expression after initiation of anoikis in primary human IEC. BMF was found on mitochondria during anoikis, as demonstrated by Western blot analysis. RNAi mediated knockdown of BMF reduced the number of apoptotic cells and led to reduced caspase 3 activity. A significant increase in phospho-AKT was determined after RNAi treatment. BMF knockdown supports survival of IEC. BMF is induced in human IEC by the loss of cell attachment and is likely to play an important role in the regulation of IEC survival. PMID:21673109

  5. Curcumin reduces expression of Bcl-2, leading to apoptosis in daunorubicin-insensitive CD34+ acute myeloid leukemia cell lines and primary sorted CD34+ acute myeloid leukemia cells

    PubMed Central

    2011-01-01

    . More importantly, curcumin suppressed Bcl-2 expression, selectively inhibited proliferation and synergistically enhanced the cytotoxicity of DNR in primary CD34+ AML cells, while showing limited lethality in normal CD34+ hematopoietic progenitors. Conclusion Curcumin down-regulates Bcl-2 and induces apoptosis in DNR-insensitive CD34+ AML cell lines and primary CD34+ AML cells. PMID:21595920

  6. Cold-Inducible Protein RBM3 Protects UV Irradiation-Induced Apoptosis in Neuroblastoma Cells by Affecting p38 and JNK Pathways and Bcl2 Family Proteins.

    PubMed

    Zhuang, Rui-Juan; Ma, Jian; Shi, Xiang; Ju, Fei; Ma, Shuang-Ping; Wang, Lei; Cheng, Bin-Feng; Ma, Yan-Wen; Wang, Mian; Li, Tong; Feng, Zhi-Wei; Yang, Hai-Jie

    2017-08-22

    Induced by hypothermia, cold-inducible protein RBM3 (RNA-binding protein motif 3), has been implicated in neuroprotection against various toxic insults such as hypoxia and ischemia. However, whether mild hypothermia and RBM3 prevent neural cells from UV irradiation-elicited apoptosis is unclear. In the present study, human neuroblastoma cell line SH-SY5Y was used as a cell model for neural cell death, and it was demonstrated that mild hypothermia protects SH-SY5Y cells from UV irradiation-induced apoptosis. However, the protective effect of mild hypothermia was abrogated when RBM3 was silenced. Conversely, the overexpression of RBM3 rescued SH-SY5Y cells from UV-induced apoptosis, as indicated by the decreased levels of cleaved caspase-3 and PARP, and increased cell survival. The analysis on the mechanism underlying RBM3-mediated neuroprotection against UV insult showed that RBM3 could substantially block the activation of p38 and JNK signaling pathways. In addition, the overexpression of RBM3 reduced the expression of pro-apoptotic proteins Bax and Bad, leaving the pro-survival protein Bcl-2 unaffected. In conclusion, RBM3 is the key mediator of mild hypothermia-related protection against UV in neuroblastoma cells, and the neuroprotective effect might be exerted through interfering with pro-apoptotic signaling pathways p38 and JNK and regulating pro-apoptotic proteins Bax and Bad.

  7. 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.

  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. 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.

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

    PubMed Central

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

    2015-01-01

    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. PMID:25766319

  11. Respiration and mitochondrial membrane potential are not required for apoptosis and anti-apoptotic action of Bcl-2 in HeLa cells.

    PubMed

    Shchepina, L A; Popova, E N; Pletjushkina, O Yu; Chernyak, B V

    2002-02-01

    The release of cytochrome c from intermembrane space of mitochondria into cytosol is one of the critical events in apoptotic cell death. The important anti-apoptotic oncoprotein Bcl-2 inhibits this process. In the present study it was shown that apoptosis and release of cytochrome c induced by staurosporine or by tumor necrosis factor-alpha in HeLa cells were not affected by inhibitors of respiration (rotenone, myxothiazol, antimycin A) or by uncouplers (CCCP, DNP) that decrease the membrane potential at the inner mitochondrial membrane. The inhibitors of respiration and the uncouplers did not affect also the anti-apoptotic activity of Bcl-2.

  12. Regulation of osteoblast development by Bcl-2-associated athanogene-1 (BAG-1)

    PubMed Central

    Greenhough, Joanna; Papadakis, Emmanouil S.; Cutress, Ramsey I.; Townsend, Paul A.; Oreffo, Richard O. C.; Tare, Rahul S.

    2016-01-01

    BCL-2-associated athanogene-1 (BAG-1) is expressed by osteoblast-lineage cells; early embryonic lethality in Bag-1 null mice, however, has limited the investigation of BAG-1 function in osteoblast development. In the present study, bone morphogenetic protein-2/BMP-2-directed osteogenic differentiation of bone marrow stromal cells (BMSCs) of Bag-1+/− (heterozygous) female mice was decreased significantly. Genes crucial for osteogenic differentiation, bone matrix formation and mineralisation were expressed at significantly lower levels in cultures of Bag-1+/− BMSCs supplemented with BMP-2, while genes with roles in inhibition of BMP-2-directed osteoblastogenesis were significantly upregulated. 17-β-estradiol (E2) enhanced responsiveness of BMSCs of wild-type and Bag-1+/− mice to BMP-2, and promoted robust BMP-2-stimulated osteogenic differentiation of BMSCs. BAG-1 can modulate cellular responses to E2 by regulating the establishment of functional estrogen receptors (ERs), crucially, via its interaction with heat shock proteins (HSC70/HSP70). Inhibition of BAG-1 binding to HSC70 by the small-molecule chemical inhibitor, Thioflavin-S, and a short peptide derived from the C-terminal BAG domain, which mediates binding with the ATPase domain of HSC70, resulted in significant downregulation of E2/ER-facilitated BMP-2-directed osteogenic differentiation of BMSCs. These studies demonstrate for the first time the significance of BAG-1-mediated protein-protein interactions, specifically, BAG-1-regulated activation of ER by HSC70, in modulation of E2-facilitated BMP-2-directed osteoblast development. PMID:27633857

  13. 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. Copyright © 2013 Elsevier Ltd. All rights reserved.

  14. 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

  15. Expression of apoptosis related proteins: RAIDD, ZIP kinase, Bim/BOD, p21, Bax, Bcl-2 and NF-kappaB in brains of patients with Down syndrome.

    PubMed

    Engidawork, E; Gulesserian, T; Seidl, R; Cairns, N; Lubec, G

    2001-01-01

    Down syndrome (DS) is a genetic disease that exhibits significant neuropathological parallels with Alzheimer's disease (AD). One of the features of DS, neuronal loss, has been hypothesized to occur as a result of apoptosis. An increasing number of proteins are implicated in apoptosis and several of them were shown to be altered in AD, however, the knowledge in DS is far from complete. To further substantiate the hypothesis that apoptosis is the underlying mechanism for neuronal loss and contribute towards the current knowledge of apoptosis in DS, we analyzed the expression of apoptosis related proteins in frontal cortex and cerebellum of DS by western blot and ELISA techniques. Quantitative analysis revealed a significant increase in DS frontal (P < 0.0001) and cerebellar (P < 0.05) Bim/BOD (Bcl-2 interacting mediator of cell death/Bcl-2 related ovarian death gene), cerebellar Bcl-2 (P < 0.01) as well as p21 (P < 0.05) levels compared to controls. No significant change was detected in Bax, RAIDD (receptor interacting protein (RIP)-associated ICH-1/CED-3-homologus protein with death domain), ZIP (Zipper interacting protein) kinase and NF-kappaB p65 levels in both regions, although frontal cortex levels of RAIDD, Bcl-2 and p21 levels tended to increase. In addition, a 45 kDa truncated form of NF-kappaB p65 displayed a significant elevation (P < 0.05) in DS cerebellum. No significant correlation had been obtained between postmortem interval and level of the proteins analyzed. With regard to age, it was only NF-kappaB p65 that showed significant correlation (r = -0.8964, P = 0.0155, n = 9) in frontal cortex of controls. These findings provide further evidence that apoptosis indeed accounts for the neuronal loss in DS but Bax and RAIDD do not appear to take part in this process.

  16. Bovine herpesvirus type 5 infection regulates Bax/BCL-2 ratio.

    PubMed

    Garcia, A F; Novais, J B; Antello, T F; Silva-Frade, C; Ferrarezi, M C; Flores, E F; Cardoso, T C

    2013-09-23

    Bovine herpesvirus 5 (BoHV-5) is an α-herpesvirus that causes neurological disease in young cattle and is also occasionally involved in reproductive disorders. Although there have been many studies of the apoptotic pathways induced by viruses belonging to the family Herpesviridae, there is little information about the intrinsic programmed cell death pathway in host-BoHV-5 interactions. We found that BoHV-5 is able to replicate in both mesenchymal and epithelial cell lines, provoking cytopathology that is characterized by cellular swelling and cell fusion. Viral antigens were detected in infected cells by immunofluorescence assay at 48 to 96 h post-infection (p.i.). At 48 to 72 h p.i., anti-apoptotic BCL-2 antigens were found at higher levels than Bax antigens; the latter is considered a pro-apoptotic protein. Infected cells had increased BCL-2 phenotype cells from 48 to 96 h p.i., based on flow cytometric analysis. At 48 to 96 h p.i., Bax mRNA was not expressed in any of the infected cell monolayers. In contrast, BCL-2 mRNA was found at high levels at all p.i. in both types of cells. BoHV-5 replication apparently modulates BCL-2 expression and gene transcription, enhancing production of virus progeny.

  17. Neurovirulent strains of Alphavirus induce apoptosis in bcl-2-expressing cells: role of a single amino acid change in the E2 glycoprotein.

    PubMed Central

    Ubol, S; Tucker, P C; Griffin, D E; Hardwick, J M

    1994-01-01

    The isolation and sequence comparison of avirulent and neurovirulent strains of polio virus, alpha virus, herpes virus, immunodeficiency virus, and other viruses have identified genetic changes that are required to cause disease in the nervous system. The molecular mechanisms by which these genetic changes result in neurovirulence are unknown. An avirulent laboratory strain of the Alphavirus Sindbis kills most cultured cell lines not by lethal parasitism, but by inducing apoptosis or programmed cell death. Transfection of cultured cells with the human bcl-2 oncogene can block Sindbis virus-induced apoptosis, resulting in a persistent viral infection resembling that observed in brains of immunodeficient mice. We investigated the possibility that neurovirulent strains of Sindbis virus could overcome the protective effects of bcl-2--a potential mechanism to explain the ability of these strains to cause fatal disease. Strains of Sindbis virus that were lethal for 2- to 4-week-old mice induced apoptotic death in cultured cells despite the presence of bcl-2. Using recombinant viruses, we show that a single amino acid change in the E2 glycoprotein of Sindbis virus confers both neurovirulence and the ability to kill cells expressing bcl-2. Images PMID:8197207

  18. Combined inhibition of NF-κB and Bcl-2 triggers synergistic reduction of viability and induces apoptosis in melanoma cells.

    PubMed

    Watanabe, Mariko; Umezawa, Kazuo; Higashihara, Masaaki; Horie, Ryouichi

    2013-01-01

    Constitutive activation of nuclear factor κB (NF-κB) characterizes melanoma cells. To explore the molecular mechanism of melanoma cell survival by constitutive NF-κB activation, we used the NF-κB inhibitor dehydroxymethylepoxyquinomicin (DHMEQ), which directly binds to NF-κB. DHMEQ abrogated constitutive NF-κB activity, which included RelA (p65)/p50 in melanoma cell lines G361 and HMV-II; however, the reduction of the viability was marginal. Expression of c-FLIP was not observed in the melanoma cell lines tested, and DHMEQ could not repress the expression of the Bcl-2 family proteins Bcl-2 and Bcl-xL. Concomitant treatment with DHMEQ and the inhibitor of antiapoptotic Bcl-2 family proteins, GX15-070, triggered synergistic reduction of the viability and induced apoptosis of G361 cells. These results indicate that abrogation of the NF-κB pathway alone is not sufficient to suppress the survival of melanoma cells. The NF-κB and the antiapoptotic Bcl-2 pathways cooperatively support the survival, and the dual targeting triggers synergistic reduction of the viability and induces apoptosis of melanoma cells.

  19. 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

  20. 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.

  1. microRNA-21 promotes cardiac fibrosis and development of heart failure with preserved left ventricular ejection fraction by up-regulating Bcl-2.

    PubMed

    Dong, Shuguang; Ma, Wenhan; Hao, Bohan; Hu, Fen; Yan, Lianhua; Yan, Xiaofei; Wang, Ya; Chen, Zhijian; Wang, Zhaohui

    2014-01-01

    The morbidity and mortality of heart failure with preserved left ventricular ejection fraction (HFpEF) were similar to those of systolic heart failure, but the pathogenesis of HFpEF remains poorly understood. It was demonstrated that, in systolic heart failure, microRNA-21 (miR-21) could inhibit the apoptosis of cardiac fibroblasts, leading to cardiac hypertrophy and myocardial fibrosis, but the role of miR-21 in HFpEF remains unknown. By employing cell culture technique, rat myocardiocytes and cardiac fibroblasts were obtained. The expression of miR-21 in the two cell types under different conditions was compared and we found that the miR-21 expression was significantly higher in cardiac fibroblasts than in myocardiocytes. We established a rat HFpEF model and harvested the tissues of cardiac apex for pathological examination, Northern blotting and so forth. We found that miR-21 expression was significantly higher in model rats than in sham-operated rats, and the model rats developed the cardiac atrophy and cardiac fibrosis. After injection of miR-21 antagonist, the the cardiac atrophy and cardiac fibrosis were conspicuously ameliorated. Both in vivo and in vitro, inhibition of miR-21 expression resulted in reduced Bcl-2 expression while over-expression of miR-21 led to elevation of Bcl-2 expression. Our study suggested that miR-21 promoted the development of HFpEF by up-regulating the expression of anti-apoptotic gene Bcl-2 and thereby suppressing the apoptosis of cardiac fibrosis.

  2. Quercetin induces p53-independent apoptosis in human prostate cancer cells by modulating Bcl-2-related proteins: a possible mediation by IGFBP-3.

    PubMed

    Vijayababu, Marati R; Kanagaraj, P; Arunkumar, A; Ilangovan, R; Dharmarajan, A; Arunakaran, J

    2006-01-01

    Quercetin, a flavonoid found in onion, grapes, green vegetables, etc., has been shown to possess potent antiproliferative effects against various malignant cells. We report insulin-like growth factor-binding protein-3 (IGFBP-3) as an effector of quercetin-induced apoptosis in human prostate cancer cell lines in a p53-independent manner. We evaluated the production of IGFBP-3 in quercetin-treated cells. Apoptosis was studied in quercetin-treated cells to study the IGFBP-3-mediated role with flow cytometry and DNA fragmentation. Protein expressions of Bcl-2, Bcl-x(L), and Bax were studied by Western blot. Increased production of IGFBP-3 was associated with the increased ratio of proapoptotic to antiapoptotic members of the Bcl-2 family. In quercetin-treated PC-3 cells, an increase in Bax protein expression and a decrease in Bcl-x(L) protein and Bcl-2 protein were observed. As PC-3 is a p53-negative cell line, these modulations of proapoptotic proteins and induction of apoptosis were independent of p53. The level of IGFBP-3 on the response of PC-3 cells to quercetin was examined. There was a twofold increase in IGFBP-3 level in conditioned media of 100 microM quercetin-treated cells. Quercetin also brought a peak at sub-G1 in PC-3 cells. Thus, increased level of IGFBP-3 was associated with increased proapoptotic proteins and apoptosis in response to quercetin, suggesting it may be a p53-independent effector of apoptosis in prostate cancer cells via its modulation of the Bax/Bcl-2 protein ratio.

  3. Nucleophosmin Mutations Induce Chemosensitivity in THP-1 Leukemia Cells by Suppressing NF-κB Activity and Regulating Bax/Bcl-2 Expression

    PubMed Central

    Zhang, Shuaishuai; Qin, Fengxian; Yang, Liyuan; Xian, Jingrong; Zou, Qin; Jin, Hongjun; Wang, Lu; Zhang, Ling

    2016-01-01

    Nucleophosmin (NPM1) - a gene that encodes for a nuclear protein with multiple functions. Mutations in NPM1 are seen in approximately one-third of acute myeloid leukemia (AML) and are generally associated with good response to induction chemotherapy. However, the mechanisms underlying this chemosensitivity are still unknown. Recent studies have established that nuclear factor-κB (NF-κB) activation is a key response of leukemia cell to chemotherapy. In this study, we transfected human monocytic leukemia THP-1 cells with the vector expressing NPM1 mutation variant (NPM1mA), and confirmed overexpression of NPM1mA at mRNA and protein levels by reverse transcription PCR (RT-PCR) and immunohistochemistry, respectively. The effects of NPM1 mutations on chemotherapeutical agents induced apoptosis, NF-κB activity and gene expression were examined using flow cytometry, luciferase reporter assays, quantitative real time PCR (qRT-PCR) and Western blot. We found that overexpression of NPM1mA in THP-1 cells sensitized these cells to apoptosis induced by chemotherapeutical agents such as daunorubicin (DNR) and cytarabine (Ara-C). Moreover, we demonstrated that expression of NPM1 mA reduced the NF-κB transcription activity of THP-1 cells upon drug treatment. In addition, restoration of NF-κB activity via TNF-α stimulation could attenuate the effect of NPM1mA overexpression on DNR-and Ara-C-induced apoptosis. Interestingly, expression of NPM1mA could upregulate Bax and downregulate Bcl-2 at mRNA and protein levels in THP-1 cells when treated with DNR or Ara-C. We also demonstrated that restoration of NF-κB activity via TNF-α pre-treatment reversed the effect of NPM1mA on the Bax/Bcl-2 expression. Furthermore, evaluation of gene expression data from The Cancer Genome Atlas (TCGA) dataset revealed that NPM1-mutated patients showed a higher expression of Bax and a lower expression of Bcl-2. These results suggest that the NPM1 gene mutations could confer increased sensitivity

  4. A Gammaherpesvirus Bcl-2 Ortholog Blocks B Cell Receptor-Mediated Apoptosis and Promotes the Survival of Developing B Cells In Vivo

    PubMed Central

    Coleman, Carrie B.; McGraw, Jennifer E.; Feldman, Emily R.; Roth, Alexa N.; Keyes, Lisa R.; Grau, Katrina R.; Cochran, Stephanie L.; Waldschmidt, Thomas J.; Liang, Chengyu; Forrest, J. Craig; Tibbetts, Scott A.

    2014-01-01

    Gammaherpesviruses such as Epstein-Barr virus (EBV) and Kaposi's sarcoma-associated herpesvirus (KSHV, HHV-8) establish lifelong latency in their hosts and are associated with the development of several types of malignancies, including a subset of B cell lymphomas. These viruses are thought to co-opt the process of B cell differentiation to latently infect a fraction of circulating memory B cells, resulting in the establishment of a stable latency setpoint. However, little is known about how this infected memory B cell compartment is maintained throughout the life of the host. We have previously demonstrated that immature and transitional B cells are long-term latency reservoirs for murine gammaherpesvirus 68 (MHV68), suggesting that infection of developing B cells contributes to the maintenance of lifelong latency. During hematopoiesis, immature and transitional B cells are subject to B cell receptor (BCR)-mediated negative selection, which results in the clonal deletion of autoreactive B cells. Interestingly, numerous gammaherpesviruses encode homologs of the anti-apoptotic protein Bcl-2, suggesting that virus inhibition of apoptosis could subvert clonal deletion. To test this, we quantified latency establishment in mice inoculated with MHV68 vBcl-2 mutants. vBcl-2 mutant viruses displayed a marked decrease in the frequency of immature and transitional B cells harboring viral genome, but this attenuation could be rescued by increased host Bcl-2 expression. Conversely, vBcl-2 mutant virus latency in early B cells and mature B cells, which are not targets of negative selection, was remarkably similar to wild-type virus. Finally, in vivo depletion of developing B cells during chronic infection resulted in decreased mature B cell latency, demonstrating a key role for developing B cells in the maintenance of lifelong latency. Collectively, these findings support a model in which gammaherpesvirus latency in circulating mature B cells is sustained in part through the

  5. Functions of the C-terminal domains of apoptosis-related proteins of the Bcl-2 family.

    PubMed

    Gómez-Fernández, Juan C

    2014-10-01

    Bcl-2 family proteins are involved in cell homeostasis, where they regulate cell death. Some of these proteins are pro-apoptotic and others pro-survival. Moreover, many of them share a similar domain composition with several of the so-called BH domains, although some only have a BH3 domain. A C-terminal domain is present in all the multi-BH domain proteins and in some of the BH3-only ones. This C-terminal domain is hydrophobic or amphipathic, for which reason it was thought when they were discovered that they were membrane anchors. Although this is indeed one of their functions, it has since been observed that they may also serve as regulators of the function of some members of this family, such as Bax. They may also serve to recognize the target membrane of some of these proteins, which only after an apoptotic signal, are incorporated into a membrane. It has been shown that peptides that imitate the sequence of C-terminal domains can form pores and may serve as a model to design cytotoxic molecules.

  6. Inhibition of Cathepsin S Induces Mitochondrial ROS That Sensitizes TRAIL-Mediated Apoptosis Through p53-Mediated Downregulation of Bcl-2 and c-FLIP.

    PubMed

    Seo, Bo Ram; Min, Kyoung-Jin; Woo, Seon Min; Choe, Misun; Choi, Kyeong Sook; Lee, Young-Kyung; Yoon, Gyesoon; Kwon, Taeg Kyu

    2017-08-01

    Cathepsin S is highly expressed in various cancer cells, and it has protumoral effects, including promotion of migration, invasion, and neovascularization. In this study, we show that inhibition of cathepsin S could sensitize cancer cells to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-mediated apoptosis. An inhibitor of cathepsin S (Z-FL-COCHO; ZFL) markedly induced apoptosis in human renal cancer cells treated with TRAIL. In contrast, combined treatment with ZFL and TRAIL had no effect on normal cells. ZFL downregulated Bcl-2 expression at the transcriptional level in a p53-dependent manner, and overexpression of Bcl-2 also markedly blocked apoptosis induced by combined treatment with ZFL and TRAIL. In addition, ZFL induced downregulation of c-FLIP, and overexpression of c-FLIP blocked the apoptosis induced by ZFL plus TRAIL. Moreover, ZFL increased the expression of Cbl, an E3 ligase of c-FLIP, in a p53-dependent manner, and knockdown of Cbl markedly prevented c-FLIP downregulation and the apoptosis induced by ZFL plus TRAIL. Interestingly, ZFL induced p53 expression via production of mitochondrial reactive oxygen species (ROS). We also demonstrated that downregulation of cathepsin S by small interfering RNA sensitized TRAIL-mediated apoptosis in Caki cells. These results reveal the importance of cathepsin S on resistance against TRAIL, and inhibition of cathepsin S activity plays a crucial role in TRAIL-mediated cell death of cancer cells. Our results indicated that inhibition of cathepsin S stimulates TRAIL-induced apoptosis through downregulation of Bcl-2 and Cbl-mediated c-FLIP by ROS-mediated p53 expression. Antioxid. Redox Signal. 27, 215-233.

  7. Cordycepin induces apoptosis by enhancing JNK and p38 kinase activity and increasing the protein expression of Bcl-2 pro-apoptotic molecules*

    PubMed Central

    He, Wei; Zhang, Mei-fang; Ye, Jun; Jiang, Ting-ting; Fang, Xu; Song, Ying

    2010-01-01

    Objective: To explore the molecular mechanism by which cordycepin inhibits cell proliferation and induces apoptosis of human colorectal cancer cells. Methods: Cell counting and MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfopheny)-2H-tetrazolium, inner salt) method were used to monitor the effects of cordycepin on cell proliferation. Flow cytometry (FCM) was used to analyze the effects of cordycepin on the cell cycle progress. Annexin V-fluorescein isothiocyanate (FITC) analysis was used to detect apoptosis at a very early stage. Caspase-Glo was used to determine caspase activity and Western blot was used to measure protein expression levels of c-Jun N-terminal kinase (JNK), p38, and Bcl-2 pro-apoptosis family. Results: The numbers of viable SW480 and SW620 cells and the proliferation of these cells were significantly reduced with increases in cordycepin concentration (P<0.01). The cell cycle progression of SW480 and SW620 was arrested at the G0/G1 phase by the addition of cordycepin, and apoptosis rates of cordycepin treatments were increased compared with the control group. Cordycepin-treated cells showed phosphatidylserine valgus, suggesting the existence of early apoptosis. Caspase-3/7 and -9 activity significantly increased and the protein expression levels of JNK, p38, and Bax, Bid, Bim, and Puma from Bcl-2 pro-apoptosis molecules also increased after the treatment with cordycepin. Conclusions: Cordycepin can inhibit SW480 and SW620 cell proliferation and induce apoptosis. Apoptosis might be induced by enhancing JNK and p38 kinase activity and increasing the protein expression of Bcl-2 pro-apoptotic molecules. PMID:20803769

  8. Cordycepin induces apoptosis by enhancing JNK and p38 kinase activity and increasing the protein expression of Bcl-2 pro-apoptotic molecules.

    PubMed

    He, Wei; Zhang, Mei-fang; Ye, Jun; Jiang, Ting-ting; Fang, Xu; Song, Ying

    2010-09-01

    To explore the molecular mechanism by which cordycepin inhibits cell proliferation and induces apoptosis of human colorectal cancer cells. Cell counting and MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfopheny)-2H-tetrazolium, inner salt) method were used to monitor the effects of cordycepin on cell proliferation. Flow cytometry (FCM) was used to analyze the effects of cordycepin on the cell cycle progress. Annexin V-fluorescein isothiocyanate (FITC) analysis was used to detect apoptosis at a very early stage. Caspase-Glo was used to determine caspase activity and Western blot was used to measure protein expression levels of c-Jun N-terminal kinase (JNK), p38, and Bcl-2 pro-apoptosis family. The numbers of viable SW480 and SW620 cells and the proliferation of these cells were significantly reduced with increases in cordycepin concentration (P<0.01). The cell cycle progression of SW480 and SW620 was arrested at the G0/G1 phase by the addition of cordycepin, and apoptosis rates of cordycepin treatments were increased compared with the control group. Cordycepin-treated cells showed phosphatidylserine valgus, suggesting the existence of early apoptosis. Caspase-3/7 and -9 activity significantly increased and the protein expression levels of JNK, p38, and Bax, Bid, Bim, and Puma from Bcl-2 pro-apoptosis molecules also increased after the treatment with cordycepin. Cordycepin can inhibit SW480 and SW620 cell proliferation and induce apoptosis. Apoptosis might be induced by enhancing JNK and p38 kinase activity and increasing the protein expression of Bcl-2 pro-apoptotic molecules.

  9. 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.

  10. 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

  11. BCL2L10 inhibits growth and metastasis of hepatocellular carcinoma both in vitro and in vivo.

    PubMed

    Bai, Yun; Wang, Jia; Han, Jing; Xie, Xiao-Li; Ji, Cheng-Guang; Yin, Jie; Chen, Lei; Wang, Cun-Kai; Jiang, Xiao-Yu; Qi, Wei; Jiang, Hui-Qing

    2017-03-01

    BCL2L10 is an apoptosis-related member of the BCL-2 protein family. The role of BCL2L10 in the pathogenesis of hepatocellular carcinoma (HCC) is poorly understood. This study was aimed to investigate the function and underlying mechanisms of BCL2L10 in HCC. BCL2L10 expression in human HCC and corresponding adjacent normal tissues was investigated by quantitative real-time PCR and Western blot. The biological functions of BCL2L10 in HCC cell lines were determined by cell viability, colony formation, cell apoptosis, cell cycle, and cell metastasis assays, and in vivo by tumorigenicity and lung metastasis assays in nude mice. Human cancer pathway PCR array was employed to explore the genes regulated by BCL2L10 in HCC. BCL2L10 was down-regulated in human HCC tissues compared to their adjacent non-tumor tissues. Ectopic expression of BCL2L10 in HepG2 and Huh7 cells suppressed cell growth as evidenced by cell viability and colony formation assay, and induced cell apoptosis. HCC cells transfected with BCL2L10 revealed an increased cell proportion arrested at G2/M phase, concomitant with a reduction in the cell proportion in S-phase as compared with control cells. Additional, BCL2L10 repressed cell migration and angiogenesis. Over-expression of BCL2L10 also restrained the tumorigenecity and lung metastasis capacity in nude mice. The activation of JAK-STAT3 signaling was suppressed by BCL2L10 in HCC. BCL2L10 was down-regulated in human HCC tissues compared to adjacent normal tissues. BCL2L10 suppressed HCC progression through inhibiting cell growth and metastasis. Thus, BCL2L10 functions as a tumor-suppressor in HCC. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  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. [Effects of garlic oil combined with resveratrol on inducting of apoptosis and expression of Fas, bcl-2 and bax in human gastric cancer cell line].

    PubMed

    Zheng, Guo-Hua; Li, Hui-Qing

    2008-01-01

    To explore the effects of garlic oil combined with resveratrol on the apoptosis and expression of Fas, bcl-2 and bax in human gastric cancer cell line MGC-803. The experiment included three groups which were the control group, the combined medicine group 1 (including 25 microg/ml oil garlic and 25 microg/ml resveratrol) and the combined medicine group 2 (including 50 microg/ml oil garlic and 50 microg/ml resveratrol). The apoptosis of cell was examined by DNA gel electrophoresis and flow cytometry for annexin v; the expression of Fas was determined by flow cytometry at the 24th hour after the treatment; the mRNA expression of bcl-2 and Bax gene were measured by RT-PCR method at the 24th ang 48th after treatment, respectively. The garlic oil combined with resveratrol induced cell apoptosis markedly at the 24th after the treatment The protein expression of Fas in the combined medicine groups was 10.59% and 14.16% respectively. As compared with the control group (5.27%), the statistical significance was obvious. The mRNA level of Bax was elevated significantly, however the mRNA expression of bcl-2 was decreased at the 24th and 48th after the treatment. The garlic oil combined with the resveratrol might obviously induce the apoptosis of gastric cancer cell line MGC-803 which be involved in increasing the expression of Fas protein and bax gene and decreasing the expression of bcl-2 gene at the same time.

  14. Chronic morphine induces up-regulation of the pro-apoptotic Fas receptor and down-regulation of the anti-apoptotic Bcl-2 oncoprotein in rat brain

    PubMed Central

    Boronat, M Assumpció; García-Fuster, M Julia; García-Sevilla, Jesús A

    2001-01-01

    This study was designed to assess the influence of activation and blockade of the endogenous opioid system in the brain on two key proteins involved in the regulation of programmed cell death: the pro-apoptotic Fas receptor and the anti-apoptotic Bcl-2 oncoprotein. The acute treatment of rats with the μ-opioid receptor agonist morphine (3 – 30 mg kg−1, i.p., 2 h) did not modify the immunodensity of Fas or Bcl-2 proteins in the cerebral cortex. Similarly, the acute treatment with low and high doses of the antagonist naloxone (1 and 100 mg kg−1, i.p., 2 h) did not alter Fas or Bcl-2 protein expression in brain cortex. These results discounted a tonic regulation through opioid receptors on Fas and Bcl-2 proteins in rat brain. Chronic morphine (10 – 100 mg kg−1, 5 days, and 10 mg kg−1, 13 days) induced marked increases (47 – 123%) in the immunodensity of Fas receptor in the cerebral cortex. In contrast, chronic morphine (5 and 13 days) decreased the immunodensity of Bcl-2 protein (15 – 30%) in brain cortex. Chronic naloxone (10 mg kg−1, 13 days) did not alter the immunodensities of Fas and Bcl-2 proteins in the cerebral cortex. The concurrent chronic treatment (13 days) of naloxone (10 mg kg−1) and morphine (10 mg kg−1) completely prevented the morphine-induced increase in Fas receptor and decrease in Bcl-2 protein immunoreactivities in the cerebral cortex. The results indicate that morphine, through the sustained activation of opioid receptors, can promote abnormal programmed cell death by enhancing the expression of pro-apoptotic Fas receptor protein and damping the expression of anti-apoptotic Bcl-2 oncoprotein. PMID:11704646

  15. Testosterone-down-regulated Akt pathway during cardiac ischemia/reperfusion: a mechanism involving BAD, Bcl-2 and FOXO3a.

    PubMed

    Huang, Chunyan; Gu, Hongmei; Zhang, Wenjun; Herrmann, Jeremy L; Wang, Meijing

    2010-11-01

    Lower levels of myocardial Akt activity in males are associated with a higher incidence of heart failure and worsened cardiac function after ischemia/reperfusion (I/R). While Akt activation by estrogen provides cardioprotection in females, no information exists regarding the effect of testosterone on the myocardial Akt pathway following I/R. We hypothesized that following I/R: (1) endogenous testosterone will decrease myocardial Akt activation in male hearts; (2) endogenous testosterone will mediate downstream signals of Akt, including Bad, Bcl-2, and FOXO3a; (3) administration of exogenous testosterone will recapitulate negative effects on the Akt pathway in castrated male hearts. Rat hearts from age-matched adult males, females, castrated males, males with androgen receptor blocker-flutamide, castrated males with chronic 5α-dihydrotestosterone (DHT) implantation, or acute testosterone infusion (ATI) (n = 9/group) were subjected to I/R (Langendorff). Castration or flutamide treatment significantly up-regulated myocardial Akt activation, increased downstream apoptosis-regulatory molecules p-Bad, Bcl-2, p-FOXO3a, but reduced Fas-L, consistent with decreased myocardial injury in male hearts following I/R. ATI administration, but not chronic DHT, reversed these effects on Akt signaling associated with further exacerbated cardiac dysfunction in castrated males. Notably, lower levels of MnSOD were observed in male hearts, and castration or flutamide treatment restored myocardial MnSOD expression to the levels of females in male hearts after I/R. Our study represents the initial evidence of testosterone-induced down-regulation of the Akt pathway in male hearts following I/R, thereby mediating cardiac injury through decreased p-Bad, reduced ratio of Bcl-2/Bax in the cytoplasm, and increased FOXO3a in the nucleus. Copyright © 2010 Elsevier Inc. All rights reserved.

  16. Dietary high fluorine induces apoptosis and alters Bcl-2, Bax, and caspase-3 protein expression in the cecal tonsil lymphocytes of broilers.

    PubMed

    Liu, Juan; Cui, Hengmin; Peng, Xi; Fang, Jing; Zuo, Zhicai; Wang, Hesong; Wu, Bangyuan; Deng, Yuanxin; Wang, Kangping

    2013-04-01

    Long-term excessive fluoride intake is known to be toxic and can lead to fluorosis and bone pathologies. However, the cellular mechanisms underlying sodium fluoride-induced cytotoxicity in the cecal tonsil lymphocytes are not well understood. The aims of this study were to investigate the effects of high dietary fluorine on apoptosis and the expression of the Bcl-2, Bax, and caspase-3 in the cecal tonsil lymphocytes of broilers. The broilers were fed on high-fluorine diets containing 0, 400, 800, and 1,200 mg/kg fluorine. As measured by flow cytometry, the percentage of apoptotic lymphocytes was significantly increased in the high-fluorine groups II and III when compared with those in the control group. Meanwhile, immunohistochemical tests showed that the Bcl-2 protein expression decreased, and the Bax and caspase-3 protein expression increased in the high-fluorine groups II and III. In conclusion, dietary fluorine in the range of 800-1,200 mg/kg increased lymphocyte apoptosis in the cecal tonsil of broilers, suggesting that the lymphocyte apoptosis in the cecal tonsil was mediated by direct effects of fluoride on the expression of Bcl-2, Bax, and caspase-3.

  17. 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

  18. The Study of Pentoxifylline Drug Effects on Renal Apoptosis and BCL-2 Gene Expression Changes Following Ischemic Reperfusion Injury in Rat

    PubMed Central

    Hashemi, Mehrdad

    2014-01-01

    Ischemia Reperfusion injury is the tissue damage caused when blood supply returns to the tissue after a period of ischemia or lack of oxygen. In this study, the effect of pentoxyfylline on BCL-2 gene expression changes and cell injury in kidney of rat following Ischemia Reperfusion were evaluated. In this experimental study, 20 male wistar rats with average weight of 250-300 g were selected and then were accidently divided them on two tenth group of control and treatment groups. In the control group, celiotomy was performed by ventral midline incision. The left kidney was isolated, and then both the renal artery and vein were obstructed. After 60 minutes of warm ischemia, vessel obstruction resolved and the right kidney was removed. 72 hours after reperfusion, tissue samples were taken from left kidney for Tunel assay. We used quantitative real time PCR for detection of BCL-2 gene expression in treated groups and then compared them to control samples. In the treatment group, the cell death changes, showed lower level than the control group. The results also showed the BCL-2 gene expression was declined in ischemia group as campared to PNT drug group. The pentoxyfylline might have a role in control of apoptosis result from Ischemia- reperfusion and quantitative real-time PCR can be used as a direct method for detection BCL-2 gene expression in tested samples and normal samples. PMID:24734070

  19. Inhibitory effects of quercetin on the progression of liver fibrosis through the regulation of NF-кB/IкBα, p38 MAPK, and Bcl-2/Bax signaling.

    PubMed

    Wang, Rong; Zhang, Hai; Wang, Yuanyuan; Song, Fuxing; Yuan, Yongfang

    2017-04-06

    Quercetin, a natural flavonoid, has been used as a nutritional supplement for its anti-inflammatory and antioxidative properties. Quercetin was reported to exhibit a wide range of pharmacological properties, including its effect on anti-hepatic fibrosis. However, the anti-fibrotic mechanisms of quercetin have not been well-characterized to date. This study aimed to investigate the protective effects of quercetin on carbon tetrachloride (CCl4)-induced liver fibrosis in rats and to clarify its anti-hepatofibrotic mechanisms. We demonstrated that quercetin exhibited in-vivo hepatoprotective and anti-fibrogenic effects against CCl4-induced liver injury by improving the pathological manifestations, thereby reducing the activities of serum total bilirubin (TBIL), alanine aminotransferase (ALT), aspartate aminotransferase (AST), and decreasing the serum levels of hyaluronic acid (HA), laminin (LN), type IV collagen (IV-C) and procollagen III peptide (PIIIP). Furthermore, treatment with quercetin 5-15mg/kg inhibited the activation of NF-κB in a dose-dependent manner via inhibition of IкBα degradation and decreased the expression of p38 MAPK by inhibiting its phosphorylation. Additionally, in a dose-dependent manner, quercetin down-regulated Bax, up-regulated Bcl-2, and subsequently inhibited caspase-3 activation. Moreover, quercetin regulated inflammation factors and hepatic stellate cells (HSCs)-activation markers, such as TNF-α, IL-6, IL-1β, Cox-2, TGF-β, α-SMA, Colla1, Colla2, TIMP-1, MMP-1, and desmin. Taken together, quercetin prevented the progression of liver fibrosis in SD rats. The anti-fibrotic mechanisms of quercetin might be associated with its ability to regulate NF-кB/IкBα, p38 MAPK anti-inflammation signaling pathways to inhibit inflammation, and regulate Bcl-2/Bax anti-apoptosis signaling pathway to prevent liver cell apoptosis.

  20. Induction of apoptosis by VB1 in breast cancer cells: the role of reactive oxygen species and Bcl-2 family proteins.

    PubMed

    Liu, Li-Hua; Zhou, Ying-Jun; Ding, Lan; Zhang, Shun-Zhi; Sun, Ji; Cao, Jian-Guo

    2014-02-01

    We have previously reported that the EVn-50 mixture of vitexins (lignan compounds) containing the purified vitexin (neolignan) compound, 6-hydroxy-4(4-hydroxy-3-methoxyphenyl)-3-hydroxymethyl‑7-methoxy-3,4-dihydro-2-naphthaldehyde, termed VB1, exhibits potent anticancer activity through the induction of apoptosis in several types of cancer cells, including MDA-MB‑231 cells. However, the exact molecular mechanisms by which VB1 induces apoptosis in MDA-MB‑231 cells have not yet been fully elucidated. In this study, to our knowledge, we provide for the first time mechanistic evidence that VB1-induced apoptosis in the human breast cancer line, MDA-MB-231, is associated with the generation of reactive oxygen species (ROS), the activation of caspases and the modulation of the expression of myeloid leukemia cell differentiation protein 1 (Mcl‑1), B cell lymphoma‑2 (Bcl-2) and Bcl-2-associated X (Bax) proteins. The silencing of Mcl-1 by RNA interference enhanced VB1-induced apoptosis. In addition, VB1 did not induce ROS generation or apoptosis in the immortalized non‑cancerous breast cell line, MCF-10A. Our findings reveal a novel mechanism underlying VB1-induced apoptosis, and highlight VB1 as a promising candidate for the therapy of human breast cancer.

  1. Small molecule XIAP inhibitors cooperate with TRAIL to induce apoptosis in childhood acute leukemia cells and overcome Bcl-2-mediated resistance.

    PubMed

    Fakler, Melanie; Loeder, Sandra; Vogler, Meike; Schneider, Katja; Jeremias, Irmela; Debatin, Klaus-Michael; Fulda, Simone

    2009-02-19

    Defects in apoptosis contribute to poor outcome in pediatric acute lymphoblastic leukemia (ALL), calling for novel strategies that counter apoptosis resistance. Here, we demonstrate for the first time that small molecule inhibitors of the antiapoptotic protein XIAP cooperate with TRAIL to induce apoptosis in childhood acute leukemia cells. XIAP inhibitors at subtoxic concentrations, but not a structurally related control compound, synergize with TRAIL to trigger apoptosis and to inhibit clonogenic survival of acute leukemia cells, whereas they do not affect viability of normal peripheral blood lymphocytes, suggesting some tumor selectivity. Analysis of signaling pathways reveals that XIAP inhibitors enhance TRAIL-induced activation of caspases, loss of mitochondrial membrane potential, and cytochrome c release in a caspase-dependent manner, indicating that they promote a caspase-dependent feedback mitochondrial amplification loop. Of note, XIAP inhibitors even overcome Bcl-2-mediated resistance to TRAIL by enhancing Bcl-2 cleavage and Bak conformational change. Importantly, XIAP inhibitors kill leukemic blasts from children with ALL ex vivo and cooperate with TRAIL to induce apoptosis. In vivo, they significantly reduce leukemic burden in a mouse model of pediatric ALL engrafted in non-obese diabetic/severe combined immunodeficient (NOD/SCID) mice. Thus, XIAP inhibitors present a promising novel approach for apoptosis-based therapy of childhood ALL.

  2. Resistance to BH3 mimetic S1 in SCLC cells that up-regulate and phosphorylate Bcl-2 through ERK1/2.

    PubMed

    Liu, Yubo; Zhang, Zhichao; Song, Ting; Liang, Furong; Xie, Mingzhou; Sheng, Hongkun

    2013-08-01

    B cell lymphoma 2 (Bcl-2) is a central regulator of cell survival that is overexpressed in the majority of small-cell lung cancers (SCLC) and contributes to both malignant transformation and therapeutic resistance. The purpose of this work was to study the key factors that determine the sensitivity of SCLC cells to Bcl-2 homology domain-3 (BH3) mimetic S1 and the mechanism underlying the resistance of BH3 mimetics. Western blot was used to evaluate the contribution of Bcl-2 family members to the cellular response of SCLC cell lines to S1. Acquired resistant cells were derived from initially sensitive H1688 cells. Quantitative PCR and gene silencing were performed to investigate Bcl-2 up-regulation. A progressive increase in the relative levels of Bcl-2 and phosphorylated Bcl-2 (pBcl-2) characterized the increased de novo and acquired resistance of SCLC cell lines. Furthermore, acute treatment of S1 induced Bcl-2 expression and phosphorylation. We showed that BH3 mimetics, including S1 and ABT-737, induced endoplasmic reticulum (ER) stress and then activated MAPK/ERK pathway. The dual function of MAPK/ERK pathway in defining BH3 mimetics was illustrated; ERK1/2 activation leaded to Bcl-2 transcriptional up-regulation and sustained phosphorylation in naïve and acquired resistant SCLC cells. pBcl-2 played a key role in creating resistance of S1 and ABT-737 not only by sequestrating pro-apoptotic proteins, but also sequestrating a positive feedback to promote ERK1/2 activation. These results provide significant novel insights into the molecular mechanisms for crosstalk between ER stress and endogenously apoptotic pathways in SCLC following BH3 mimetics treatment. © 2013 The British Pharmacological Society.

  3. Resistance to BH3 mimetic S1 in SCLC cells that up-regulate and phosphorylate Bcl-2 through ERK1/2

    PubMed Central

    Liu, Yubo; Zhang, Zhichao; Song, Ting; Liang, Furong; Xie, Mingzhou; Sheng, Hongkun

    2013-01-01

    Background and Purpose B cell lymphoma 2 (Bcl-2) is a central regulator of cell survival that is overexpressed in the majority of small-cell lung cancers (SCLC) and contributes to both malignant transformation and therapeutic resistance. The purpose of this work was to study the key factors that determine the sensitivity of SCLC cells to Bcl-2 homology domain-3 (BH3) mimetic S1 and the mechanism underlying the resistance of BH3 mimetics. Experimental Approaches Western blot was used to evaluate the contribution of Bcl-2 family members to the cellular response of SCLC cell lines to S1. Acquired resistant cells were derived from initially sensitive H1688 cells. Quantitative PCR and gene silencing were performed to investigate Bcl-2 up-regulation. Key Results A progressive increase in the relative levels of Bcl-2 and phosphorylated Bcl-2 (pBcl-2) characterized the increased de novo and acquired resistance of SCLC cell lines. Furthermore, acute treatment of S1 induced Bcl-2 expression and phosphorylation. We showed that BH3 mimetics, including S1 and ABT-737, induced endoplasmic reticulum (ER) stress and then activated MAPK/ERK pathway. The dual function of MAPK/ERK pathway in defining BH3 mimetics was illustrated; ERK1/2 activation leaded to Bcl-2 transcriptional up-regulation and sustained phosphorylation in naïve and acquired resistant SCLC cells. pBcl-2 played a key role in creating resistance of S1 and ABT-737 not only by sequestrating pro-apoptotic proteins, but also sequestrating a positive feedback to promote ERK1/2 activation. Conclusions and Implications These results provide significant novel insights into the molecular mechanisms for crosstalk between ER stress and endogenously apoptotic pathways in SCLC following BH3 mimetics treatment. PMID:23651505

  4. Laser Acupuncture Exerts Neuroprotective Effects via Regulation of Creb, Bdnf, Bcl-2, and Bax Gene Expressions in the Hippocampus

    PubMed Central

    Yun, Yeong-Chan; Yoon, Sun-Bee; Kim, Dohyeong; Choi, Dong-Hee; Lee, Yu-Mi

    2017-01-01

    Acupuncture has a positive effect on cognitive deficits. However, the effects of laser acupuncture (LA) on cognitive function and its mechanisms of action are unclear. The present study aimed to evaluate the effects of LA on middle cerebral artery occlusion- (MCAO-) induced cognitive impairment and its mechanisms of action. Transient focal cerebral ischemia was modeled in adult Sprague-Dawley rats by MCAO. After LA or manual-acupuncture (MA) treatment at the GV20 and HT7 for 2 weeks, hippocampal-dependent memory was evaluated using the Morris water maze (MWM) test. The hippocampus was dissected to analyze choline acetyltransferase (ChAT) immunoreactivity and Creb, Bdnf, Bcl-2, and Bax gene expressions. MWM test demonstrated a significant improvement in hippocampal-dependent memory in the MCAO rats after LA treatment. LA treatment significantly reversed the postischemic decrease in ChAT immunoreactivity in the hippocampal CA1 region. LA treatment significantly normalized gene expression in the hippocampus which had been altered by MCAO, especially upregulating gene expression of Creb, Bdnf, and Bcl-2 and downregulating gene expression of Bax. This study suggests that LA treatment could improve cognitive impairment in MCAO rats to enhance the cholinergic system in the hippocampal CA1 region and to exert a neuroprotective effect by regulating Creb, Bdnf, Bcl-2, and Bax gene expressions. PMID:28408940

  5. Laser Acupuncture Exerts Neuroprotective Effects via Regulation of Creb, Bdnf, Bcl-2, and Bax Gene Expressions in the Hippocampus.

    PubMed

    Yun, Yeong-Chan; Jang, Dongyeop; Yoon, Sun-Bee; Kim, Dohyeong; Choi, Dong-Hee; Kwon, O-Sang; Lee, Yu-Mi; Youn, Daehwan

    2017-01-01

    Acupuncture has a positive effect on cognitive deficits. However, the effects of laser acupuncture (LA) on cognitive function and its mechanisms of action are unclear. The present study aimed to evaluate the effects of LA on middle cerebral artery occlusion- (MCAO-) induced cognitive impairment and its mechanisms of action. Transient focal cerebral ischemia was modeled in adult Sprague-Dawley rats by MCAO. After LA or manual-acupuncture (MA) treatment at the GV20 and HT7 for 2 weeks, hippocampal-dependent memory was evaluated using the Morris water maze (MWM) test. The hippocampus was dissected to analyze choline acetyltransferase (ChAT) immunoreactivity and Creb, Bdnf, Bcl-2, and Bax gene expressions. MWM test demonstrated a significant improvement in hippocampal-dependent memory in the MCAO rats after LA treatment. LA treatment significantly reversed the postischemic decrease in ChAT immunoreactivity in the hippocampal CA1 region. LA treatment significantly normalized gene expression in the hippocampus which had been altered by MCAO, especially upregulating gene expression of Creb, Bdnf, and Bcl-2 and downregulating gene expression of Bax. This study suggests that LA treatment could improve cognitive impairment in MCAO rats to enhance the cholinergic system in the hippocampal CA1 region and to exert a neuroprotective effect by regulating Creb, Bdnf, Bcl-2, and Bax gene expressions.

  6. 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

  7. Cyanide-induced death of dopaminergic cells is mediated by uncoupling protein-2 up-regulation and reduced Bcl-2 expression

    SciTech Connect

    Zhang, X.; Li, L.; Zhang, L.; Borowitz, J.L.; Isom, G.E.

    2009-07-01

    Cyanide is a potent inhibitor of mitochondrial oxidative metabolism and produces mitochondria-mediated death of dopaminergic neurons and sublethal intoxications that are associated with a Parkinson-like syndrome. Cyanide toxicity is enhanced when mitochondrial uncoupling is stimulated following up-regulation of uncoupling protein-2 (UCP-2). In this study, the role of a pro-survival protein, Bcl-2, in cyanide-mediated cell death was determined in a rat dopaminergic immortalized mesencephalic cell line (N27 cells). Following pharmacological up-regulation of UCP-2 by treatment with Wy14,643, cyanide reduced cellular Bcl-2 expression by increasing proteasomal degradation of the protein. The increased turnover of Bcl-2 was mediated by an increase of oxidative stress following UCP-2 up-regulation. The oxidative stress involved depletion of mitochondrial glutathione (mtGSH) and increased H{sub 2}O{sub 2} generation. Repletion of mtGSH by loading cells with glutathione ethyl ester reduced H{sub 2}O{sub 2} generation and in turn blocked the cyanide-induced decrease of Bcl-2. To determine if UCP-2 mediated the response, RNAi knock down was conducted. The RNAi decreased cyanide-induced depletion of mtGSH, reduced H{sub 2}O{sub 2} accumulation, and inhibited down-regulation of Bcl-2, thus blocking cell death. To confirm the role of Bcl-2 down-regulation in the cell death, it was shown that over-expression of Bcl-2 by cDNA transfection attenuated the enhancement of cyanide toxicity after UCP-2 up-regulation. It was concluded that UCP-2 up-regulation sensitizes cells to cyanide by increasing cellular oxidative stress, leading to an increase of Bcl-2 degradation. Then the reduced Bcl-2 levels sensitize the cells to cyanide-mediated cell death.

  8. Cyanide-induced death of dopaminergic cells is mediated by uncoupling protein-2 up-regulation and reduced Bcl-2 expression.

    PubMed

    Zhang, X; Li, L; Zhang, L; Borowitz, J L; Isom, G E

    2009-07-01

    Cyanide is a potent inhibitor of mitochondrial oxidative metabolism and produces mitochondria-mediated death of dopaminergic neurons and sublethal intoxications that are associated with a Parkinson-like syndrome. Cyanide toxicity is enhanced when mitochondrial uncoupling is stimulated following up-regulation of uncoupling protein-2 (UCP-2). In this study, the role of a pro-survival protein, Bcl-2, in cyanide-mediated cell death was determined in a rat dopaminergic immortalized mesencephalic cell line (N27 cells). Following pharmacological up-regulation of UCP-2 by treatment with Wy14,643, cyanide reduced cellular Bcl-2 expression by increasing proteasomal degradation of the protein. The increased turnover of Bcl-2 was mediated by an increase of oxidative stress following UCP-2 up-regulation. The oxidative stress involved depletion of mitochondrial glutathione (mtGSH) and increased H2O2 generation. Repletion of mtGSH by loading cells with glutathione ethyl ester reduced H2O2 generation and in turn blocked the cyanide-induced decrease of Bcl-2. To determine if UCP-2 mediated the response, RNAi knock down was conducted. The RNAi decreased cyanide-induced depletion of mtGSH, reduced H2O2 accumulation, and inhibited down-regulation of Bcl-2, thus blocking cell death. To confirm the role of Bcl-2 down-regulation in the cell death, it was shown that over-expression of Bcl-2 by cDNA transfection attenuated the enhancement of cyanide toxicity after UCP-2 up-regulation. It was concluded that UCP-2 up-regulation sensitizes cells to cyanide by increasing cellular oxidative stress, leading to an increase of Bcl-2 degradation. Then the reduced Bcl-2 levels sensitize the cells to cyanide-mediated cell death.

  9. Cyanide-induced Death of Dopaminergic Cells is Mediated by Uncoupling Protein-2 Up-regulation and Reduced Bcl-2 Expression

    PubMed Central

    Zhang, X.; Li, L.; Zhang, L.; Borowitz, J.L.; Isom, G.E.

    2009-01-01

    Cyanide is a potent inhibitor of mitochondrial oxidative metabolism and produces mitochondria-mediated death of dopaminergic neurons and sublethal intoxications are associated with a Parkinson-like syndrome. Cyanide toxicity is enhanced when mitochondrial uncoupling is stimulated following up-regulation of uncoupling protein-2 (UCP-2). In this study, the role of a pro-survival protein, Bcl-2, in cyanide-mediated cell death was determined in a rat dopaminergic immortalized mesencephalic cell line (N27 cells). Following pharmacological up-regulation of UCP-2 by treatment with Wy14,643, cyanide reduced cellular Bcl-2 expression by increasing proteasomal degradation of the protein. The increased turnover of Bcl-2 was mediated by an increase of oxidative stress following UCP-2 up-regulation. The oxidative stress involved depletion of mitochondrial glutathione (mtGSH) and increased H2O2 generation. Repletion of mtGSH by loading cells with glutathione ethyl ester reduced H2O2 generation and in turn blocked the cyanide-induced decrease of Bcl-2. To determine if UCP-2 mediated the response, RNAi knock down was conducted. The RNAi decreased cyanide-induced depletion of mtGSH, reduced H2O2 accumulation, and inhibited down-regulation of Bcl-2, thus blocking cell death. To confirm the role of Bcl-2 down-regulation in the cell death, it was shown that overexpression of Bcl-2 by cDNA transfection attenuated the enhancement of cyanide toxicity after UCP-2 up-regulation. It was concluded that UCP-2 up-regulation sensitizes cells to cyanide by increasing cellular oxidative stress, leading to an increase of Bcl-2 degradation. Then the reduced Bcl-2 levels sensitize the cells to cyanide-mediated cell death. PMID:19361538

  10. 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.

  11. 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.

  12. miR-497 and miR-302b Regulate Ethanol-induced Neuronal Cell Death through BCL2 Protein and Cyclin D2*

    PubMed Central

    Yadav, Sanjay; Pandey, Ankita; Shukla, Aruna; Talwelkar, Sarang S.; Kumar, Ashutosh; Pant, Aditya B.; Parmar, Devendra

    2011-01-01

    In chronic alcoholism, brain shrinkage and cognitive defects because of neuronal death are well established, although the sequence of molecular events has not been fully explored yet. We explored the role of microRNAs (miRNAs) in ethanol-induced apoptosis of neuronal cells. Ethanol-sensitive miRNAs in SH-SY5Y, a human neuroblastoma cell line, were identified using real-time PCR-based TaqMan low-density arrays. Long-term exposure to ethanol (0.5% v/v for 72 h) produced a maximum increase in expression of miR-497 (474-fold) and miR-302b (322-fold). Similar to SH-SY5Y, long-term exposure to ethanol induced miR-497 and miR-302b in IMR-32, another human neuroblastoma cell line. Using in silico approaches, BCL2 and cyclin D2 (CCND2) were identified as probable target genes of these miRNAs. Cotransfection studies with 3′-UTR of these genes and miRNA mimics have demonstrated that BCL2 is a direct target of miR-497 and that CCND2 is regulated negatively by either miR-302b or miR-497. Overexpression of either miR-497 or miR-302b reduced expression of their identified target genes and increased caspase 3-mediated apoptosis of SH-SY5Y cells. However, overexpression of only miR-497 increased reactive oxygen species formation, disrupted mitochondrial membrane potential, and induced cytochrome c release (mitochondria-related events of apoptosis). Moreover, ethanol induced changes in miRNAs, and their target genes were substantially prevented by pre-exposure to GSK-3B inhibitors. In conclusion, our studies have shown that ethanol-induced neuronal apoptosis follows both the mitochondria-mediated (miR-497- and BCL2-mediated) and non-mitochondria-mediated (miR-302b- and CCND2-mediated) pathway. PMID:21878650

  13. miR-497 and miR-302b regulate ethanol-induced neuronal cell death through BCL2 protein and cyclin D2.

    PubMed

    Yadav, Sanjay; Pandey, Ankita; Shukla, Aruna; Talwelkar, Sarang S; Kumar, Ashutosh; Pant, Aditya B; Parmar, Devendra

    2011-10-28

    In chronic alcoholism, brain shrinkage and cognitive defects because of neuronal death are well established, although the sequence of molecular events has not been fully explored yet. We explored the role of microRNAs (miRNAs) in ethanol-induced apoptosis of neuronal cells. Ethanol-sensitive miRNAs in SH-SY5Y, a human neuroblastoma cell line, were identified using real-time PCR-based TaqMan low-density arrays. Long-term exposure to ethanol (0.5% v/v for 72 h) produced a maximum increase in expression of miR-497 (474-fold) and miR-302b (322-fold). Similar to SH-SY5Y, long-term exposure to ethanol induced miR-497 and miR-302b in IMR-32, another human neuroblastoma cell line. Using in silico approaches, BCL2 and cyclin D2 (CCND2) were identified as probable target genes of these miRNAs. Cotransfection studies with 3'-UTR of these genes and miRNA mimics have demonstrated that BCL2 is a direct target of miR-497 and that CCND2 is regulated negatively by either miR-302b or miR-497. Overexpression of either miR-497 or miR-302b reduced expression of their identified target genes and increased caspase 3-mediated apoptosis of SH-SY5Y cells. However, overexpression of only miR-497 increased reactive oxygen species formation, disrupted mitochondrial membrane potential, and induced cytochrome c release (mitochondria-related events of apoptosis). Moreover, ethanol induced changes in miRNAs, and their target genes were substantially prevented by pre-exposure to GSK-3B inhibitors. In conclusion, our studies have shown that ethanol-induced neuronal apoptosis follows both the mitochondria-mediated (miR-497- and BCL2-mediated) and non-mitochondria-mediated (miR-302b- and CCND2-mediated) pathway.

  14. Evidence that CED-9/Bcl2 and CED-4/Apaf-1 localization is not consistent with the current model for C. elegans apoptosis induction

    PubMed Central

    Pourkarimi, E; Greiss, S; Gartner, A

    2012-01-01

    In C. elegans, the BH3-only domain protein EGL-1, the Apaf-1 homolog CED-4 and the CED-3 caspase are required for apoptosis induction, whereas the Bcl-2 homolog CED-9 prevents apoptosis. Mammalian B-cell lymphoma 2 (Bcl-2) inhibits apoptosis by preventing the release of the Apaf-1 (apoptotic protease-activating factor 1) activator cytochrome c from mitochondria. In contrast, C. elegans CED-9 is thought to inhibit CED-4 by sequestering it at the outer mitochondrial membrane by direct binding. We show that CED-9 associates with the outer mitochondrial membrane within distinct foci that do not overlap with CED-4, which is predominantly perinuclear and does not localize to mitochondria. CED-4 further accumulates in the perinuclear space in response to proapoptotic stimuli such as ionizing radiation. This increased accumulation depends on EGL-1 and is abrogated in ced-9 gain-of-function mutants. CED-4 accumulation is not sufficient to trigger apoptosis execution, even though it may prime cells for apoptosis. Our results suggest that the cell death protection conferred by CED-9 cannot be solely explained by a direct interaction with CED-4. PMID:21886181

  15. [Effects of adipose-derived stem cells transplantation on the neuronal apoptosis and the expression of Bcl-2 and caspase-12 in the brain post focal cerebral ischemia in rats].

    PubMed

    Lin, Xiao-hui; Liu, Nan; Xiao, Ying-chun; Chen, Rong-hua; DU, Hou-wei; Wang, Jie-hua; Zhang, Yi-xian; Liu, De-shan

    2011-01-01

    To investigate the effects of adipose-derived stem cells (ADSCs) transplantation on neuronal apoptosis in the brain after focal cerebral ischemia in rats. 72 male adult Sprague-Dawley rats were randomly divided into 4 groups: Sham-operated group , Middle cerebral artery occlusion (MCAO) group, Vehicle group and ADSC-treated group (n=18). MCAO model was established with the modified Longa's method. One day after right MCAO, 30 μL of cell suspension containing 1×10(6); cells were injected into the lateral ventricle of ADSC-treated group and the same dose of PBS was given to the vehicle group. At 4 d, 7 d and 14 d after MCAO, the apoptosis of neuron was detected by terminal deoxynucleotidyl transferase-mediated DNA nick-end labeling (TUNEL) method and the expression of Bcl-2 and caspase-12 in ischemic region was detected by immunohistochemistry and RT-PCR. TUNEL-positive cells in ischemic region of ADSC-treated group were less than that in MCAO group and Vehicle group at 4 d, 7 d and 14 d post MCAO (P<0.05). Compared with MCAO group and Vehicle group, the expression of Bcl-2 significantly up-regulated while caspase-12 expression significantly decreased in ADSC-treated group at any time point post MCAO (P<0.05). The transplantation of ADSCs can reduce neuronal apoptosis of rats with cerebral ischemic injury partly by promoting the expression of Bcl-2 which participates in apoptotic signals after mitochondrial damage and inhibiting the expression of caspase-12 which mediates endoplasmic reticulum (ER) stress-induced apoptosis.

  16. 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

  17. 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.

  18. 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

  19. Hypoxic human cancer cells are sensitized to BH-3 mimetic–induced apoptosis via downregulation of the Bcl-2 protein Mcl-1

    PubMed Central

    Harrison, Luke R.E.; Micha, Dimitra; Brandenburg, Martin; Simpson, Kathryn L.; Morrow, Christopher J.; Denneny, Olive; Hodgkinson, Cassandra; Yunus, Zaira; Dempsey, Clare; Roberts, Darren; Blackhall, Fiona; Makin, Guy; Dive, Caroline

    2011-01-01

    Solid tumors contain hypoxic regions in which cancer cells are often resistant to chemotherapy-induced apoptotic cell death. Therapeutic strategies that specifically target hypoxic cells and promote apoptosis are particularly appealing, as few normal tissues experience hypoxia. We have found that the compound ABT-737, a Bcl-2 homology domain 3 (BH-3) mimetic, promotes apoptotic cell death in human colorectal carcinoma and small cell lung cancer cell lines exposed to hypoxia. This hypoxic induction of apoptosis was mediated through downregulation of myeloid cell leukemia sequence 1 (Mcl-1), a Bcl-2 family protein that serves as a biomarker for ABT-737 resistance. Downregulation of Mcl-1 in hypoxia was independent of hypoxia-inducible factor 1 (HIF-1) activity and was consistent with decreased global protein translation. In addition, ABT-737 induced apoptosis deep within tumor spheroids, consistent with an optimal hypoxic oxygen tension being necessary to promote ABT-737–induced cell death. Tumor xenografts in ABT-737–treated mice also displayed significantly more apoptotic cells within hypoxic regions relative to normoxic regions. Synergies between ABT-737 and other cytotoxic drugs were maintained in hypoxia, suggesting that this drug may be useful in combination with chemotherapeutic agents. Taken together, these findings suggest that Mcl-1–sparing BH-3 mimetics may induce apoptosis in hypoxic tumor cells that are resistant to other chemotherapeutic agents and may have a role in combinatorial chemotherapeutic regimens for treatment of solid tumors. PMID:21393866

  20. BCL-2 family protein, BAD is down-regulated in breast cancer and inhibits cell invasion

    SciTech Connect

    Cekanova, Maria; Fernando, Romaine I.; Siriwardhana, Nalin; Sukhthankar, Mugdha; Parra, Columba de la; Woraratphoka, Jirayus; Malone, Christine; Ström, Anders; Baek, Seung J.; Wade, Paul A.; Saxton, Arnold M.; Donnell, Robert M.; Pestell, Richard G.; and others

    2015-02-01

    We have previously demonstrated that the anti-apoptotic protein BAD is expressed in normal human breast tissue and shown that BAD inhibits expression of cyclin D1 to delay cell-cycle progression in breast cancer cells. Herein, expression of proteins in breast tissues was studied by immunohistochemistry and results were analyzed statistically to obtain semi-quantitative data. Biochemical and functional changes in BAD-overexpressing MCF7 breast cancer cells were evaluated using PCR, reporter assays, western blotting, ELISA and extracellular matrix invasion assays. Compared to normal tissues, Grade II breast cancers expressed low total/phosphorylated forms of BAD in both cytoplasmic and nuclear compartments. BAD overexpression decreased the expression of β-catenin, Sp1, and phosphorylation of STATs. BAD inhibited Ras/MEK/ERK and JNK signaling pathways, without affecting the p38 signaling pathway. Expression of the metastasis-related proteins, MMP10, VEGF, SNAIL, CXCR4, E-cadherin and TlMP2 was regulated by BAD with concomitant inhibition of extracellular matrix invasion. Inhibition of BAD by siRNA increased invasion and Akt/p-Akt levels. Clinical data and the results herein suggest that in addition to the effect on apoptosis, BAD conveys anti-metastatic effects and is a valuable prognostic marker in breast cancer. - Highlights: • BAD and p-BAD expressions are decreased in breast cancer compared with normal breast tissue. • BAD impedes breast cancer invasion and migration. • BAD inhibits the EMT and transcription factors that promote cancer cell migration. • Invasion and migration functions of BAD are distinct from the BAD's role in apoptosis.

  1. Chemosensitizing Effect of Astragalus Polysaccharides on Nasopharyngeal Carcinoma Cells by Inducing Apoptosis and Modulating Expression of Bax/Bcl-2 Ratio and Caspases.

    PubMed

    Zhou, Zhen; Meng, Minhua; Ni, Haifeng

    2017-01-26

    BACKGROUND Platinum-based chemotherapy is the most effective regimen for nasopharyngeal carcinoma, which presents highly invasive and metastatic activity. However, the dose-related toxicity of chemotherapy agents limits the dose administration. Astragalus polysaccharide (APS) is the major active ingredient extracted from Chinese herb Radix Astragali and is proven to be active against carcinomas. We aimed to assess the chemosensitizing effects of Astragalus polysaccharides on nasopharyngeal carcinoma in vitro and in vivo and to explore the underlying mechanism. MATERIAL AND METHODS We used BALB/c nu/nu mice and human nasopharyngeal carcinoma cell lines CNE-1, CNE-2, and SUNE-1. MTT, Annexin V/PI, Western blot analysis, and TUNEL assay were carried out. RESULTS APS significantly promoted anti-proliferative and apoptotic effects of cisplatin on nasopharyngeal carcinoma cells. APS also enhanced the anti-tumor effects and cisplatin-induced apoptosis in the xenograft model. The level of Bcl-2 decreased, while the levels of Bax, caspase-3, and caspase-9 increased in cisplatin combined with APS treatment compared to cisplatin only treatment. The ratio of Bax to Bcl-2 was significantly enhanced by the APS to cisplatin. CONCLUSIONS APS enhanced the anti-proliferative and apoptotic effect of cisplatin by modulating expression of Bax/Bcl-2 ratio and caspases on nasopharyngeal carcinoma cells and in the xenograft model.

  2. Chemosensitizing Effect of Astragalus Polysaccharides on Nasopharyngeal Carcinoma Cells by Inducing Apoptosis and Modulating Expression of Bax/Bcl-2 Ratio and Caspases

    PubMed Central

    Zhou, Zhen; Meng, Minhua; Ni, Haifeng

    2017-01-01

    Background Platinum-based chemotherapy is the most effective regimen for nasopharyngeal carcinoma, which presents highly invasive and metastatic activity. However, the dose-related toxicity of chemotherapy agents limits the dose administration. Astragalus polysaccharide (APS) is the major active ingredient extracted from Chinese herb Radix Astragali and is proven to be active against carcinomas. We aimed to assess the chemosensitizing effects of Astragalus polysaccharides on nasopharyngeal carcinoma in vitro and in vivo and to explore the underlying mechanism. Material/Methods We used BALB/c nu/nu mice and human nasopharyngeal carcinoma cell lines CNE-1, CNE-2, and SUNE-1. MTT, Annexin V/PI, Western blot analysis, and TUNEL assay were carried out. Results APS significantly promoted anti-proliferative and apoptotic effects of cisplatin on nasopharyngeal carcinoma cells. APS also enhanced the anti-tumor effects and cisplatin-induced apoptosis in the xenograft model. The level of Bcl-2 decreased, while the levels of Bax, caspase-3, and caspase-9 increased in cisplatin combined with APS treatment compared to cisplatin only treatment. The ratio of Bax to Bcl-2 was significantly enhanced by the APS to cisplatin. Conclusions APS enhanced the anti-proliferative and apoptotic effect of cisplatin by modulating expression of Bax/Bcl-2 ratio and caspases on nasopharyngeal carcinoma cells and in the xenograft model. PMID:28124680

  3. Aflatoxin B1 affects apoptosis and expression of Bax, Bcl-2, and Caspase-3 in thymus and bursa of fabricius in broiler chickens.

    PubMed

    Peng, Xi; Chen, Kejie; Chen, Jin; Fang, Jing; Cui, Hengmin; Zuo, Zhicai; Deng, Junliang; Chen, Zhengli; Geng, Yi; Lai, Weimin

    2016-09-01

    Aflatoxin B1 is known as a mycotoxin that develops various health problems of animals, the effects of AFB1 on thymus and bursa of Fabricius in chickens are not clear. The objective of this study was to investigate the apoptosis of thymus and bursa of Fabricius in broilers fed with AFB1 . Two hundred Avian broilers were randomly divided into four groups of 50 each, namely control group and three AFB1 groups fed with 0.15 mg, 0.3 mg, and 0.6 mg AFB1 /kg diet, respectively. In this study, flow cytometer and immunohistochemical approaches were used to determine the percentage of apoptotic cells and the expression of Bax, Bcl-2, and Caspase-3. The results showed that consumption of AFB1 diets results in increased percentage of apoptotic cells and increased expression of Caspase-3 in both thymus and bursa of Fabricius. The expression of Bax was increased and the expression of Bcl-2 was decreased in the thymus, but no significant changes in Bax and Bcl-2 expression were observed in the bursa of Fabricius when broilers fed with AFB1 . These findings suggest that adverse effects of AFB1 on thymus and bursa of Fabricius in broilers were confirmed by increased apoptotic cells and abnormal expression of Caspase-3. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1113-1120, 2016. © 2015 Wiley Periodicals, Inc.

  4. Inositol hexaphosphate induces apoptosis by coordinative modulation of P53, Bcl-2 and sequential activation of caspases in 7,12 dimethylbenz[a]anthracene exposed mouse epidermis.

    PubMed

    Singh, Jaya; Gupta, Krishna P

    2008-01-01

    Inositol hexaphosphate (IP6) is a major constituent of most cereals, legumes, nuts, oil seeds, and soybean. Anticancer effects of IP6 have been demonstrated in different experimental models. Besides reducing cell proliferation, IP6 increases differentiation of malignant cells, often resulting in restoring the normal phenotype. Exogenously administered IP6 is rapidly taken into the cells and dephosphorylated to lower-phosphate, inositol phosphates, which further interfere with signal transduction pathways and cell cycle arrest. Enhanced immunity and antioxidant properties could also contribute to tumor cell destruction. However, the molecular mechanisms underlying this anticancer action are not fully understood. The present study deals with the effect of topical application of IP6 on some of the selective and critical events of apoptosis in DMBA exposed mouse epidermis. IP6 showed an inhibition of DMBA-induced mutant (mt) p53 expression. Similarly, DMBA induced over expression of Bcl-2 was also reversed by topical treatment of IP6. In addition to the modulation of mt p53 and Bcl-2 expressions, IP6 brought the DMBA-inhibited activity of caspases back to the normal or induced it above the normal levels. The effects of IP6 appeared to be the function of its dose and the duration of its exposure. These results suggested that topically applied IP6 directly induces apoptotic machinery by modulating the expression of mt p53, Bcl-2, and caspase activity.

  5. Dieldrin promotes proteolytic cleavage of poly(ADP-ribose) polymerase and apoptosis in dopaminergic cells: protective effect of mitochondrial anti-apoptotic protein Bcl-2.

    PubMed

    Kitazawa, Masashi; Anantharam, Vellareddy; Kanthasamy, Arthi; Kanthasamy, Anumantha G

    2004-06-01

    Previously, we demonstrated that the organochlorine pesticide dieldrin induces mitochondrial depolarization, caspase-3 activation and apoptosis in dopaminergic PC12 cells. We also demonstrated that protein kinase Cdelta (PKCdelta), a member of a novel PKC family of proteins, is proteolytically activated by caspase-3 to mediate apoptotic cell death processes. In the present study, we have further characterized the protective effect of the major mitochondrial anti-apoptotic protein Bcl-2 against dieldrin-induced apoptotic events in dopaminergic cells. Exposure to dieldrin (30-100 microM) produced significant cytotoxicity and caspase-3 activation within 3h in vector-transfected PC12 cells, whereas human Bcl-2-transfected PC12 cells were almost completely resistant to dieldrin-induced cytotoxicity and caspase-3 activation. Also, dieldrin (30-300 microM) treatment induced proteolytic cleavage of poly(ADP-ribose) polymerase (PARP), which was blocked by pretreatment with caspase-3 inhibitors Z-DEVD-FMK and Z-VAD-FMK. Additionally, dieldrin-induced chromatin condensation and DNA fragmentation were completely blocked in Bcl-2-overexpressed PC12 cells as compared to vector control cells. Together, these results clearly indicate that overexpression of mitochondrial anti-apoptotic protein protects against dieldrin-induced apoptotic cell death and further suggest that dieldrin primarily alters mitochondrial function to initiate apoptotic cell death in dopaminergic cells.

  6. 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

  7. BCL-2 family protein, BAD is down-regulated in breast cancer and inhibits cell invasion.

    PubMed

    Cekanova, Maria; Fernando, Romaine I; Siriwardhana, Nalin; Sukhthankar, Mugdha; De la Parra, Columba; Woraratphoka, Jirayus; Malone, Christine; Ström, Anders; Baek, Seung J; Wade, Paul A; Saxton, Arnold M; Donnell, Robert M; Pestell, Richard G; Dharmawardhane, Suranganie; Wimalasena, Jay

    2015-02-01

    We have previously demonstrated that the anti-apoptotic protein BAD is expressed in normal human breast tissue and shown that BAD inhibits expression of cyclin D1 to delay cell-cycle progression in breast cancer cells. Herein, expression of proteins in breast tissues was studied by immunohistochemistry and results were analyzed statistically to obtain semi-quantitative data. Biochemical and functional changes in BAD-overexpressing MCF7 breast cancer cells were evaluated using PCR, reporter assays, western blotting, ELISA and extracellular matrix invasion assays. Compared to normal tissues, Grade II breast cancers expressed low total/phosphorylated forms of BAD in both cytoplasmic and nuclear compartments. BAD overexpression decreased the expression of β-catenin, Sp1, and phosphorylation of STATs. BAD inhibited Ras/MEK/ERK and JNK signaling pathways, without affecting the p38 signaling pathway. Expression of the metastasis-related proteins, MMP10, VEGF, SNAIL, CXCR4, E-cadherin and TlMP2 was regulated by BAD with concomitant inhibition of extracellular matrix invasion. Inhibition of BAD by siRNA increased invasion and Akt/p-Akt levels. Clinical data and the results herein suggest that in addition to the effect on apoptosis, BAD conveys anti-metastatic effects and is a valuable prognostic marker in breast cancer.

  8. Garlic (Allium sativum) Fresh Juice Induces Apoptosis in Human Oral Squamous Cell Carcinoma: The Involvement of Caspase-3, Bax and Bcl-2

    PubMed Central

    Farhadi, Farrokh; Jahanpour, Salar; Hazem, Kameliya; Aghbali, Amirala; Baradran, Behzad; Vahid Pakdel, Seyyed Mahdi

    2015-01-01

    Background and aims. There is no report on the apoptotic impact of Allium sativum L.(Garlic) on the oral squamous cell carcinoma (KB); hence, this study was designed to survey the apoptotic effects of garlic fresh juice (GFJ) on the KB cells. Materials and methods. MTTassay (MicrocultureTetrazolium Assay) was carried out to evaluate the cytotoxicity of GFJ on KB cells. Furthermore, TUNEL(Terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling)and DNA fragmentation tests were performed to determine if GFJ is able to induce apoptosis in KB cells. Also a standard kit was used to assess caspase-3 activity in KB cells. Also western blotting was employed to evaluate the effect of GFJ on Bax:Bcl-2 ratio. Results. Significant cytotoxic effects were observed for the minimum used concentration (1μg/mL) as calculated to be 77.97±2.3% for 24 h and 818±3.1% for 36h of incubation (P < 0.001). Furthermore, TUNEL and DNA fragmentation tests corroborated the apoptosis inducing activity of GFJ. Consistently, after treating KB cells with GFJ(1μg/mL), caspase-3 activity and Bax:Bcl-2 ratio were raised by 7.3±0.6 and (P <0.001) folds, respectively. Conclusion. The results of this study advanced that GFJ induces apoptosis in the KB cells through increasing caspase-3 activity and Bax:Bcl2 ratio which could be attributed to its organo-sulfurcomponents. PMID:26889365

  9. The pan-Bcl-2 blocker obatoclax promotes the expression of Puma, Noxa, and Bim mRNA and induces apoptosis in neoplastic mast cells.

    PubMed

    Peter, Barbara; Cerny-Reiterer, Sabine; Hadzijusufovic, Emir; Schuch, Karina; Stefanzl, Gabriele; Eisenwort, Gregor; Gleixner, Karoline V; Hoermann, Gregor; Mayerhofer, Matthias; Kundi, Michael; Baumgartner, Sigrid; Sperr, Wolfgang R; Pickl, Winfried F; Willmann, Michael; Valent, Peter

    2014-01-01

    Advanced SM is an incurable neoplasm with short survival time. So far, no effective therapy is available for these patients. We and others have shown recently that neoplastic MC in ASM and MCL express antiapoptotic Mcl-1, Bcl-2, and Bcl-xL. In this study, we examined the effects of the pan-Bcl-2 family blocker obatoclax (GX015-070) on primary neoplastic MC, the human MC leukemia cell line HMC-1, and the canine mastocytoma cell line C2. Obatoclax was found to inhibit proliferation in primary human neoplastic MC (IC₅₀: 0.057 μM), in HMC-1.2 cells expressing KIT D816V (IC₅₀: 0.72 μM), and in HMC-1.1 cells lacking KIT D816V (IC₅₀: 0.09 μM), as well as in C2 cells (IC₅₀: 0.74 μM). The growth-inhibitory effects of obatoclax in HMC-1 cells were accompanied by an increase in expression of Puma, Noxa, and Bim mRNA, as well as by apoptosis, as evidenced by microscopy, TUNEL assay, and caspase cleavage. Viral-mediated overexpression of Mcl-1, Bcl-xL, or Bcl-2 in HMC-1 cells was found to introduce partial resistance against apoptosis-inducing effects of obatoclax. We were also able to show that obatoclax synergizes with several other antineoplastic drugs, including dasatinib, midostaurin, and bortezomib, in producing apoptosis and/or growth arrest in neoplastic MC. Together, obatoclax exerts major growth-inhibitory effects on neoplastic MC and potentiates the antineoplastic activity of other targeted drugs. Whether these drug effects can be translated to application in patients with advanced SM remains to be determined.

  10. Chelerythrine down regulates expression of VEGFA, BCL2 and KRAS by arresting G-Quadruplex structures at their promoter regions

    NASA Astrophysics Data System (ADS)

    Jana, Jagannath; Mondal, Soma; Bhattacharjee, Payel; Sengupta, Pallabi; Roychowdhury, Tanaya; Saha, Pranay; Kundu, Pallob; Chatterjee, Subhrangsu

    2017-01-01

    A putative anticancer plant alkaloid, Chelerythrine binds to G-quadruplexes at promoters of VEGFA, BCL2 and KRAS genes and down regulates their expression. The association of Chelerythrine to G-quadruplex at the promoters of these oncogenes were monitored using UV absorption spectroscopy, fluorescence anisotropy, circular dichroism spectroscopy, CD melting, isothermal titration calorimetry, molecular dynamics simulation and quantitative RT-PCR technique. The pronounced hypochromism accompanied by red shifts in UV absorption spectroscopy in conjunction with ethidium bromide displacement assay indicates end stacking mode of interaction of Chelerythrine with the corresponding G-quadruplex structures. An increase in fluorescence anisotropy and CD melting temperature of Chelerythrine-quadruplex complex revealed the formation of stable Chelerythrine-quadruplex complex. Isothermal titration calorimetry data confirmed that Chelerythrine-quadruplex complex formation is thermodynamically favourable. Results of quantative RT-PCR experiment in combination with luciferase assay showed that Chelerythrine treatment to MCF7 breast cancer cells effectively down regulated transcript level of all three genes, suggesting that Chelerythrine efficiently binds to in cellulo quadruplex motifs. MD simulation provides the molecular picture showing interaction between Chelerythrine and G-quadruplex. Binding of Chelerythrine with BCL2, VEGFA and KRAS genes involved in evasion, angiogenesis and self sufficiency of cancer cells provides a new insight for the development of future therapeutics against cancer.

  11. Chelerythrine down regulates expression of VEGFA, BCL2 and KRAS by arresting G-Quadruplex structures at their promoter regions

    PubMed Central

    Jana, Jagannath; Mondal, Soma; Bhattacharjee, Payel; Sengupta, Pallabi; Roychowdhury, Tanaya; Saha, Pranay; Kundu, Pallob; Chatterjee, Subhrangsu

    2017-01-01

    A putative anticancer plant alkaloid, Chelerythrine binds to G-quadruplexes at promoters of VEGFA, BCL2 and KRAS genes and down regulates their expression. The association of Chelerythrine to G-quadruplex at the promoters of these oncogenes were monitored using UV absorption spectroscopy, fluorescence anisotropy, circular dichroism spectroscopy, CD melting, isothermal titration calorimetry, molecular dynamics simulation and quantitative RT-PCR technique. The pronounced hypochromism accompanied by red shifts in UV absorption spectroscopy in conjunction with ethidium bromide displacement assay indicates end stacking mode of interaction of Chelerythrine with the corresponding G-quadruplex structures. An increase in fluorescence anisotropy and CD melting temperature of Chelerythrine-quadruplex complex revealed the formation of stable Chelerythrine-quadruplex complex. Isothermal titration calorimetry data confirmed that Chelerythrine-quadruplex complex formation is thermodynamically favourable. Results of quantative RT-PCR experiment in combination with luciferase assay showed that Chelerythrine treatment to MCF7 breast cancer cells effectively down regulated transcript level of all three genes, suggesting that Chelerythrine efficiently binds to in cellulo quadruplex motifs. MD simulation provides the molecular picture showing interaction between Chelerythrine and G-quadruplex. Binding of Chelerythrine with BCL2, VEGFA and KRAS genes involved in evasion, angiogenesis and self sufficiency of cancer cells provides a new insight for the development of future therapeutics against cancer. PMID:28102286

  12. PAWR-mediated suppression of BCL2 promotes switching of 3-azido withaferin A (3-AWA)-induced autophagy to apoptosis in prostate cancer cells

    PubMed Central

    Rah, Bilal; Rasool, Reyaz ur; Nayak, Debasis; Yousuf, Syed Khalid; Mukherjee, Debaraj; Kumar, Lekha Dinesh; Goswami, Anindya

    2015-01-01

    An active medicinal component of plant origin with an ability to overcome autophagy by inducing apoptosis should be considered a therapeutically active lead pharmacophore to control malignancies. In this report, we studied the effect of concentration-dependent 3-AWA (3-azido withaferin A) sensitization to androgen-independent prostate cancer (CaP) cells which resulted in a distinct switching of 2 interrelated conserved biological processes, i.e. autophagy and apoptosis. We have observed 3 distinct parameters which are hallmarks of autophagy in our studies. First, a subtoxic concentration of 3-AWA resulted in an autophagic phenotype with an elevation of autophagy markers in prostate cancer cells. This led to a massive accumulation of MAP1LC3B and EGFP-LC3B puncta coupled with gradual degradation of SQSTM1. Second, higher toxic concentrations of 3-AWA stimulated ER stress in CaP cells to turn on apoptosis within 12 h by elevating the expression of the proapoptotic protein PAWR, which in turn suppressed the autophagy-related proteins BCL2 and BECN1. This inhibition of BECN1 in CaP cells, leading to the disruption of the BCL2-BECN1 interaction by overexpressed PAWR has not been reported so far. Third, we provide evidence that pawr-KO MEFs exhibited abundant autophagy signs even at toxic concentrations of 3-AWA underscoring the relevance of PAWR in switching of autophagy to apoptosis. Last but not least, overexpression of EGFP-LC3B and DS-Red-BECN1 revealed a delayed apoptosis turnover at a higher concentration of 3-AWA in CaP cells. In summary, this study provides evidence that 3-AWA is a strong anticancer candidate to abrogate protective autophagy. It also enhanced chemosensitivity by sensitizing prostate cancer cells to apoptosis through induction of PAWR endorsing its therapeutic potential. PMID:25803782

  13. Apigenin induces caspase-dependent apoptosis in human lung cancer A549 cells through Bax- and Bcl-2-triggered mitochondrial pathway.

    PubMed

    Lu, Hsu-Feng; Chie, Yu-Jie; Yang, Ming-Sung; Lee, Ching-Sung; Fu, Jene-John; Yang, Jai-Sing; Tan, Tzu-Wei; Wu, Shin-Hwar; Ma, Yi-Shih; Ip, Siu-Wan; Chung, Jing-Gung

    2010-06-01

    The molecular mechanism and possible signaling pathway of apigenin-induced cytotoxicity and apoptosis in human lung cancer cells has not been reported. We investigated the role of ROS, Ca2+, caspases and Bax proteins and mitochondria membrane potential in apigenin-induced apoptosis in A549 cells. Cells were incubated with different concentrations of apigenin then cell morphological changes, DNA damage, cell viability and apoptosis were determined by Comet assay, and flow cytometric analysis. Sub-G1 phase was also examined. Western blot analysis was used to determined the levels of Bax and Bcl-2 and apoptosis associated proteins, and confocal laser microscope for examining the translocation of associated protein after exposed to apigenin. The results indicated that apigenin induced morphological changes, decreased percentage of viable cells and induced apoptosis dose- and time-dependently. DAPI staining and Comet assay also confirmed that apigenin-induced DNA condensation and damage. The levels of caspase-3, -8 and -9 involved in apigenin-induced apoptosis indicating caspase-dependent pathway was induced by apigenin. Western blotting showed that apigenin promoted cytochrome c levels and also induced dysfunction of mitochondria leading to the release of cytochrome c, AIF and Endo G, causing the activation of caspase-9 and -3, then apoptosis in A549 cells.

  14. Protein Kinase RNA-Like Endoplasmic Reticulum Kinase-Mediated Bcl-2 Protein Phosphorylation Contributes to Evodiamine-Induced Apoptosis of Human Renal Cell Carcinoma Cells

    PubMed Central

    Wu, Wen-Shin; Chien, Chih-Chiang; Chen, Yen-Chou; Chiu, Wen-Ta

    2016-01-01

    We investigated the anticancer mechanism of evodiamine (EVO) against the viability of human A498 renal cell carcinoma (RCC) cells in vitro and in vivo. The in vitro study showed that EVO decreased the viability of A498 cells with the occurrence of apoptotic characteristics such as hypodiploid cells, DNA ladders, chromatin-condensed cells, and cleaved caspase (Casp)-3/poly(ADP ribose) polymerase (PARP) proteins. Pharmacological studies using chemical inhibitors of mitogen-activated protein kinase (MAPK) and phosphoinositide 3-kinase (PI3K) indicated that phosphorylation of the c-Jun N-terminal kinase (JNK) protein participated in EVO-induced cell death of A498 cells, and application of the JNK inhibitor, SP600125 (SP), inhibited EVO-induced cleavage of the Casp-3/PARP proteins and chromatin condensation according to Giemsa staining. EVO disruption of the mitochondrial membrane potential (MMP) with increased protein levels of the phosphorylated Bcl-2 protein (p-Bcl-2) was prevented by JNK inhibitors in A498 cells. A structure-activity relationship study showed that a methyl group at position 14 in EVO was important for its apoptotic effects and increased p-Bcl-2 protein in A498 cells. Furthermore, significant increases in the phosphorylated endoplasmic reticular stress protein, protein kinase RNA-like endoplasmic reticulum kinase (p-PERK at Thr980), by EVO were detected in A498 cells, and the PERK inhibitor, GSK2606414, significantly suppressed EVO-induced apoptosis, p-JNK, p-PERK, and cleaved PARP proteins. The in vivo study showed that EVO significantly reduced RCC growth elicited by a subcutaneous injection of A498 cells, and an increased protein level of p-PERK was observed according to an immunohistochemical analysis. Apoptosis by EVO was also demonstrated in other RCC cells such as 786-O, ACHN, and Caki-1 cells. This is the first study to demonstrate the anti-RCC effect of EVO via apoptosis in vitro and in vivo, and activation of JNK and PERK to induce Bcl-2

  15. Involvement of Bcl-2, Src, and ERα in gossypol-mediated growth inhibition and apoptosis in human uterine leiomyoma and myometrial cells

    PubMed Central

    Zhu, Yan; Xie, Shu-wu; Zhang, Jian-feng; Zhang, Ting-ting; Zhou, Jie-yun; Cao, Yang; Cao, Lin

    2010-01-01

    Aim: To investigate the effect of gossypol on the growth of cultured human uterine leiomyoma and myometrial cells, the level of Bcl-2 and the activity of Src and estrogen receptor (ERα). Methods: Human uterine leiomyoma and adjacent normal myometrial cells were cultured in vitro. Both cell types were treated with a graded concentration of gossypol. Cell viability was assayed using CCK-8. Morphological change was observed with optical and electronic microscopy. Apoptosis was evaluated using TUNEL assay. Levels of Bcl-2, ERα and Src were analyzed using Western blotting. Results: Gossypol significantly inhibited growth and promoted apoptosis in cultured human uterine leiomyoma cells with the IC50 value and its corresponding 95% confidence intervals (CI) of 6.5 (4.0–10.5), 9.0 (4.9–16.5), and 7.5 (4.0–14.1) μmol/L at 20, 40, and 60 h, respectively. Gossypol exerted inhibitory effects on the myometrial cells with the IC50 value and its 95% CI of 49.1 (28.3–85.0), 14.5 (7.7–27.4), and 2.6 (1.2–5.6) μmol/L at 20, 40, and 60 h, respectively. Compared with control, gossypol 0.1-3.0 μmol/L markedly decreased the protein expression of Bcl-2 (P<0.05) in both leiomyoma and myometrial cells in a concentration-dependent manner, and significantly suppressed the level of phospho-Tyr416Src (P<0.05) in both cell types at 3.0 μmol/L without obvious alteration of c-Src and phospho-Tyr527Src levels (P>0.05). In addition, gossypol markedly reduced both the expression of ERα (P<0.05) at the low concentration of 0.1 μmol/L in the myometrial cells and the level of phospho-ser167ERα (P<0.05) at the high concentration of 3.0 μmol/L in the leiomyoma cells. Conclusion: Gossypol inhibits proliferation and induces apoptosis in human uterine leiomyoma and myometrial cells. It is likely that the mechanisms of action involve reducing the protein level of Bcl-2 and the activity of Src and ERα. PMID:21102482

  16. MiR-34a, a promising novel biomarker for benzene toxicity, is involved in cell apoptosis triggered by 1,4-benzoquinone through targeting Bcl-2.

    PubMed

    Chen, Yujiao; Sun, Pengling; Guo, Xiaoli; Gao, Ai

    2017-02-01

    Exposure to benzene is inevitable, and concerns regarding the adverse health effects of benzene have been raised. Most investigators found that benzene exposure induced hematotoxicity. In this regard, Our study aimed to explore a novel potential biomarker of adverse health effects following benzene exposure and the toxic mechanisms of benzene metabolites in vitro. This study consisted of 314 benzene-exposed workers and 288 control workers, an air benzene concentration of who were 2.64 ± 1.60 mg/m(3) and 0.05 ± 0.01 mg/m(3), respectively. In this population-based study, miR-34a expression was elevated in benzene-exposed workers. The correlation of miR-34a with the airborne benzene concentration, S-phenylmercapturic acid (S-PMA) and trans, trans-muconic acid (t, t-MA), all of which reflect benzene exposure, was found. Correlation analysis indicated that miR-34a was associated with peripheral blood count, alanine transaminase (ALT) and oxidative stress. Furthermore, multivariate analysis demonstrated that miR-34a expression was strongly associated with white blood cell count (structure loadings = 0.952). In population-based study, miR-34a had the largest contribution to altered peripheral blood counts, which reflect benzene-induced hematotoxicity. The role of miR-34a in benzene toxicity was assessed using lentiviral vector transfection. Results revealed that 1,4-benzoquinone induced abnormal cell apoptosis and simultaneously upregulated miR-34a accompanied with decreased Bcl-2. Finally, inhibition of miR-34a elevated Bcl-2 and decreased 1,4-benzoquinone-induced apoptosis. In conclusion, miR-34a was observed to be involved in benzene-induced hematotoxicity by targeting Bcl-2 and could be regarded as a potential novel biomarker for benzene toxicity.

  17. The Association between Splenocyte Apoptosis and Alterations of Bax, Bcl-2 and Caspase-3 mRNA Expression, and Oxidative Stress Induced by Dietary Nickel Chloride in Broilers

    PubMed Central

    Huang, Jianying; Cui, Hengmin; Peng, Xi; Fang, Jing; Zuo, Zhicai; Deng, Junliang; Wu, Bangyuan

    2013-01-01

    Two hundred and forty avian broilers were equally divided into four groups, and raised with a corn-soybean basal diet or the same diet supplemented with 300, 600, 900 mg/kg NiCl2 for 42 days. Numbers or percentages of apoptotic splenocytes by flow cytometry (FCM) and TUNEL were higher (p < 0.05 or p < 0.01) in the 300, 600 and 900 mg/kg groups than those in the control group. Results measured by qRT-PCR and ELISA showed that mRNA expression and contents were significantly higher (p < 0.05 or p < 0.01) in Bax and Caspase-3, and were significantly lower (p < 0.05 or p < 0.01) in Bcl-2 of the 300, 600 and 900 mg/kg groups. Also, the SOD, CAT and GSH-Px activities, and the ability to inhibit hydroxyl radical, and GSH contents were significantly decreased (p < 0.05 or p < 0.01), and MDA contents were increased (p < 0.05 or p < 0.01) in all groups. In conclusion, dietary NiCl2 in excess of 300 mg/kg caused apoptosis, altered Bax, Bcl-2 and Caspase-3 mRNA expression levels and contents, and induced oxidative stress in the spleen. Also, splenocyte apoptosis was closely related to the alternations of Bax, Bcl-2 and Caspase-3 mRNA expression, and oxidative damage. The splenic immunity and blood filtration functions were impaired in broilers. PMID:24351749

  18. 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

  19. 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.

  20. 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.

  1. Antioxidant tert-butylhydroquinone ameliorates arsenic-induced intracellular damages and apoptosis through induction of Nrf2-dependent antioxidant responses as well as stabilization of anti-apoptotic factor Bcl-2 in human keratinocytes.

    PubMed

    Duan, Xiaoxu; Li, Jinlong; Li, Wei; Xing, Xiaoyue; Zhang, Yang; Li, Wei; Zhao, Lu; Sun, Guifan; Gao, Xing-Hua; Li, Bing

    2016-05-01

    Human skin is a known target site of inorganic arsenic with effects ranging from hyperkeratosis to dermal malignancies. Tert-butylhydroquinone (tBHQ), approved food-grade phenolic antioxidant, is demonstrated to induce remarkable antioxidant activity in a variety of cells and tissues. The present study aimed at the protective effects of tBHQ on arsenic-induced cytotoxicity and apoptosis in human keratinocytes. Our results demonstrated that tBHQ antagonized arsenic-induced decrease of cell viability, generation of reactive oxygen species (ROS) and lipid peroxidation, as well as reduction of antioxidative enzymes superoxide dismutase (SOD) and catalase (CAT) activities. We also found that tBHQ relieved the G2/M phase arrest by arsenic exposure, which was associated with altering the expression of cell cycle regulators cyclin D1 and CDK4. tBHQ treatment further reduced the numbers of arsenic-induced mitochondrial-mediated apoptotic cells, which occurred concomitantly with the effective recovery of mitochondrial membrane potential (ΔΨm) depolarization, the release of cytochrome c releasing from the mitochondrial as well as the survival signal related factor caspase 3 activation. Our experiments then confirmed that tBHQ activated nuclear factor E2-related factor 2 (NRF2) pathway by increasing NRF2 protein in both nucleus and cytoplasm and upregulating NRF2 downstream targets quinine oxidoreductase 1 (NQO1) and heme oxygenase-1 (HO-1). More interestingly, arsenic-induced decrease of anti-apoptotic factor B-cell lymphoma-2 (Bcl-2) and increase of pro-apoptotic factor Bcl-2-associated X protein (Bax) could all be reversed by tBHQ pretreatment. These results suggested together that tBHQ could ameliorate arsenic-induced cytotoxicity and apoptosis, which might be linked with the induction of Nrf2-dependent antioxidant responses as well as stabilization of anti-apoptotic factor Bcl-2 in human keratinocytes. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. 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.

  3. 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.

  4. 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.

  5. 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

  6. Genetic Variants in the Apoptosis Gene BCL2L1 Improve Response to Interferon-Based Treatment of Hepatitis C Virus Genotype 3 Infection

    PubMed Central

    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

    2015-01-01

    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. PMID:25648321

  7. Pentoxifylline and the proteasome inhibitor MG132 induce apoptosis in human leukemia U937 cells through a decrease in the expression of Bcl-2 and Bcl-XL and phosphorylation of p65

    PubMed Central

    2013-01-01

    Background In Oncology, the resistance of the cancerous cells to chemotherapy continues to be the principal limitation. The nuclear factor-kappa B (NF-κB) transcription factor plays an important role in tumor escape and resistance to chemotherapy and this factor regulates several pathways that promote tumor survival including some antiapoptotic proteins such as Bcl-2 and Bcl-XL. In this study, we investigated, in U937 human leukemia cells, the effects of PTX and the MG132 proteasome inhibitor, drugs that can disrupt the NF-κB pathway. For this, we evaluated viability, apoptosis, cell cycle, caspases-3, -8, -9, cytochrome c release, mitochondrial membrane potential loss, p65 phosphorylation, and the modification in the expression of pro- and antiapoptotic genes, and the Bcl-2 and Bcl-XL antiapoptotic proteins. Results The two drugs affect the viability of the leukemia cells in a time-dependent manner. The greatest percentage of apoptosis was obtained with a combination of the drugs; likewise, PTX and MG132 induce G1 phase cell cycle arrest and cleavage of caspases -3,-8, -9 and cytochrome c release and mitochondrial membrane potential loss in U937 human leukemia cells. In these cells, PTX and the MG132 proteasome inhibitor decrease p65 (NF-κB subunit) phosphorylation and the antiapoptotic proteins Bcl-2 and Bcl-XL. We also observed, with a combination of these drugs overexpression of a group of the proapoptotic genes BAX, DIABLO, and FAS while the genes BCL-XL, MCL-1, survivin, IκB, and P65 were downregulated. Conclusions The two drugs used induce apoptosis per se, this cytotoxicity was greater with combination of both drugs. These observations are related with the caspases -9, -3 cleavage and G1 phase cell cycle arrest, and a decrease in p65 phosphorylation and Bcl-2 and Bcl-XL proteins. As well as this combination of drugs promotes the upregulation of the proapoptotic genes and downregulation of antiapoptotic genes. These observations strongly confirm

  8. Cell Cycle Arrest and Apoptosis Induction via Modulation of Mitochondrial Integrity by Bcl-2 Family Members and Caspase Dependence in Dracaena cinnabari-Treated H400 Human Oral Squamous Cell Carcinoma.

    PubMed

    Alabsi, Aied M; Lim, Kai Li; Paterson, Ian C; Ali-Saeed, Rola; Muharram, Bushra A

    2016-01-01

    Dracaena cinnabari Balf.f. is a red resin endemic to Socotra Island, Yemen. Although there have been several reports on its therapeutic properties, information on its cytotoxicity and anticancer effects is very limited. This study utilized a bioassay-guided fractionation approach to determine the cytotoxic and apoptosis-inducing effects of D. cinnabari on human oral squamous cell carcinoma (OSCC). The cytotoxic effects of D. cinnabari crude extract were observed in a panel of OSCC cell lines and were most pronounced in H400. Only fractions DCc and DCd were active on H400 cells; subfractions DCc15 and DCd16 exhibited the greatest cytotoxicity against H400 cells and D. cinnabari inhibited cells proliferation in a time-dependent manner. This was achieved primarily via apoptosis where externalization of phospholipid phosphatidylserine was observed using DAPI/Annexin V fluorescence double staining mechanism studied through mitochondrial membrane potential assay cytochrome c enzyme-linked immunosorbent and caspases activities revealed depolarization of mitochondrial membrane potential (MMP) and significant activation of caspases 9 and 3/7, concomitant with S phase arrest. Apoptotic proteins array suggested that MMP was regulated by Bcl-2 proteins family as results demonstrated an upregulation of Bax, Bad, and Bid as well as downregulation of Bcl-2. Hence, D. cinnabari has the potential to be developed as an anticancer agent.

  9. Cell Cycle Arrest and Apoptosis Induction via Modulation of Mitochondrial Integrity by Bcl-2 Family Members and Caspase Dependence in Dracaena cinnabari-Treated H400 Human Oral Squamous Cell Carcinoma

    PubMed Central

    Alabsi, Aied M.; Lim, Kai Li; Paterson, Ian C.; Ali-Saeed, Rola; Muharram, Bushra A.

    2016-01-01

    Dracaena cinnabari Balf.f. is a red resin endemic to Socotra Island, Yemen. Although there have been several reports on its therapeutic properties, information on its cytotoxicity and anticancer effects is very limited. This study utilized a bioassay-guided fractionation approach to determine the cytotoxic and apoptosis-inducing effects of D. cinnabari on human oral squamous cell carcinoma (OSCC). The cytotoxic effects of D. cinnabari crude extract were observed in a panel of OSCC cell lines and were most pronounced in H400. Only fractions DCc and DCd were active on H400 cells; subfractions DCc15 and DCd16 exhibited the greatest cytotoxicity against H400 cells and D. cinnabari inhibited cells proliferation in a time-dependent manner. This was achieved primarily via apoptosis where externalization of phospholipid phosphatidylserine was observed using DAPI/Annexin V fluorescence double staining mechanism studied through mitochondrial membrane potential assay cytochrome c enzyme-linked immunosorbent and caspases activities revealed depolarization of mitochondrial membrane potential (MMP) and significant activation of caspases 9 and 3/7, concomitant with S phase arrest. Apoptotic proteins array suggested that MMP was regulated by Bcl-2 proteins family as results demonstrated an upregulation of Bax, Bad, and Bid as well as downregulation of Bcl-2. Hence, D. cinnabari has the potential to be developed as an anticancer agent. PMID:27123447

  10. Epstein-Barr virus interactions with the Bcl-2 protein family and apoptosis in human tumor cells*

    PubMed Central

    Fu, Qin; He, Chen; Mao, Zheng-rong

    2013-01-01

    Epstein-Barr virus (EBV), a human gammaherpesvirus carried by more than 90% of the world’s population, is associated with malignant tumors such as Burkitt’s lymphoma (BL), Hodgkin lymphoma, post-transplant lymphoma, extra-nodal natural killer/T cell lymphoma, and nasopharyngeal and gastric carcinomas in immune-compromised patients. In the process of infection, EBV faces challenges: the host cell environment is harsh, and the survival and apoptosis of host cells are precisely regulated. Only when host cells receive sufficient survival signals may they immortalize. To establish efficiently a lytic or long-term latent infection, EBV must escape the host cell immunologic mechanism and resist host cell apoptosis by interfering with multiple signaling pathways. This review details the apoptotic pathway disrupted by EBV in EBV-infected cells and describes the interactions of EBV gene products with host cellular factors as well as the function of these factors, which decide the fate of the host cell. The relationships between other EBV-encoded genes and proteins of the B-cell leukemia/lymphoma (Bcl) family are unknown. Still, EBV seems to contribute to establishing its own latency and the formation of tumors by modifying events that impact cell survival and proliferation as well as the immune response of the infected host. We discuss potential therapeutic drugs to provide a foundation for further studies of tumor pathogenesis aimed at exploiting novel therapeutic strategies for EBV-associated diseases. PMID:23303627

  11. Bcl-2 functionally interacts with inositol 1,4,5-trisphosphate receptors to regulate calcium release from the ER in response to inositol 1,4,5-trisphosphate

    PubMed Central

    Chen, Rui; Valencia, Ignacio; Zhong, Fei; McColl, Karen S.; Roderick, H. Llewelyn; Bootman, Martin D.; Berridge, Michael J.; Conway, Stuart J.; Holmes, Andrew B.; Mignery, Gregory A.; Velez, Patricio; Distelhorst, Clark W.

    2004-01-01

    Inositol 1,4,5-trisphosphate (InsP3) receptors (InsP3Rs) are channels responsible for calcium release from the endoplasmic reticulum (ER). We show that the anti-apoptotic protein Bcl-2 (either wild type or selectively localized to the ER) significantly inhibited InsP3-mediated calcium release and elevation of cytosolic calcium in WEHI7.2 T cells. This inhibition was due to an effect of Bcl-2 at the level of InsP3Rs because responses to both anti-CD3 antibody and a cell-permeant InsP3 ester were decreased. Bcl-2 inhibited the extent of calcium release from the ER of permeabilized WEHI7.2 cells, even at saturating concentrations of InsP3, without decreasing luminal calcium concentration. Furthermore, Bcl-2 reduced the open probability of purified InsP3Rs reconstituted into lipid bilayers. Bcl-2 and InsP3Rs were detected together in macromolecular complexes by coimmunoprecipitation and blue native gel electrophoresis. We suggest that this functional interaction of Bcl-2 with InsP3Rs inhibits InsP3R activation and thereby regulates InsP3-induced calcium release from the ER. PMID:15263017

  12. Cannabinoid receptor type 2 agonist attenuates apoptosis by activation of phosphorylated CREB-Bcl-2 pathway after subarachnoid hemorrhage in rats.

    PubMed

    Fujii, Mutsumi; Sherchan, Prativa; Soejima, Yoshiteru; Hasegawa, Yu; Flores, Jerry; Doycheva, Desislava; Zhang, John H

    2014-11-01

    Early brain injury (EBI) which comprises of vasogenic edema and apoptotic cell death is an important component of subarachnoid hemorrhage (SAH) pathophysiology. This study evaluated whether cannabinoid receptor type 2 (CB2R) agonist, JWH133, attenuates EBI after SAH and whether CB2R stimulation reduces pro-apoptotic caspase-3 via up-regulation of cAMP response element-binding protein (CREB)-Bcl-2 signaling pathway. Male Sprague-Dawley rats (n=123) were subjected to SAH by endovascular perforation. Rats received vehicle or JWH133 at 1h after SAH. Neurological deficits and brain water content were evaluated at 24h after SAH. Western blot was performed to quantify phosphorylated CREB (pCREB), Bcl-2, and cleaved caspase-3 levels. Neuronal cell death was evaluated with terminal deoxynucleotidyl transferase-mediated uridine 5'-triphosphate-biotin nick end-labeling staining. Additionally, CREB siRNA was administered to manipulate the proposed pathway. JWH133 (1.0mg/kg) improved neurological deficits and reduced brain water content in left hemisphere 24h after SAH. JWH133 significantly increased activated CREB (pCREB) and Bcl-2 levels and significantly decreased cleaved caspase-3 levels in left hemisphere 24h after SAH. CREB siRNA reversed the effects of treatment. TUNEL positive neurons in the cortex were reduced with JWH133 treatment. Thus, CB2R stimulation attenuated EBI after SAH possibly through activation of pCREB-Bcl-2 pathway. Copyright © 2014 Elsevier Inc. All rights reserved.

  13. The peroxisomes strike BAK: Regulation of peroxisome integrity by the Bcl-2 family.

    PubMed

    Chipuk, Jerry Edward; Luna-Vargas, Mark P A

    2017-03-06

    Within the mitochondrial pathway of apoptosis, VDAC2 controls both the localization and proapoptotic activity of BAK. In this issue, Hosoi et al. (2017. J. Cell Biol. https://doi.org/10.1083/jcb.201605002) find that loss of VDAC2 diverts BAK into peroxisome membranes, revealing the ability of BAK to control peroxisome membrane integrity and the release of soluble peroxisomal matrix proteins. © 2017 Chipuk and Luna-Vargas.

  14. Zinc down regulates Apaf-1-dependent Bax/Bcl-2 mediated caspases activation during aluminium induced neurotoxicity.

    PubMed

    Singla, Neha; Dhawan, D K

    2015-02-01

    Aluminium (Al), a ubiquitous element in nature is associated with the onset of Alzheimer's disease. On the other hand, zinc (Zn) is an essential trace element that regulates large number of physiological processes in the human body. The present study was conducted to explore the role of zinc, if any, in regulating apoptotic machinery during Al induced neurodegeneration in rat. Male sprague dawley rats weighing 140-160 g were divided into four different groups viz: Normal control, Al treated (100 mg/kg b.wt./day), Zn treated (227 mg/l) and combined Al and Zn treated. All the treatments were carried out for a total duration of 8 weeks. Al treatment resulted in a significant increase in the protein expressions of cytochrome c, Bax, Apaf-1, caspase 9, caspase 3 (p17), caspase 8, caspase 6, caspase 7 but decreased the Bcl-2 in both the cerebrum and cerebellum. However, Zn supplementation to Al treated rats resulted in a reduction in the protein expressions of cytochrome c, Bax, Apaf-1, caspase 9, caspase 3 (p17), caspase 8, caspase 6 and caspase 7 whereas it elevated the Bcl-2 in both the regions. Further, gene expressions of caspase 3 and caspase 9 were also found to be elevated after Al treatment, which however were reduced following Zn co-treatment. The electron-microscopic analysis of brain revealed that Al intoxication resulted in a number of degenerative signs at ultrastructural level, which were appreciably improved upon Zn supplementation. The present study suggests that Zn provides protection against Al induced neurotoxicity by triggering anti-apoptotic machinery.

  15. PI3K and Bcl-2 inhibition primes glioblastoma cells to apoptosis through downregulation of Mcl-1 and Phospho-BAD.

    PubMed

    Pareja, Fresia; Macleod, David; Shu, Chang; Crary, John F; Canoll, Peter D; Ross, Alonzo H; Siegelin, Markus D

    2014-07-01

    Glioblastoma multiforme (GBM) is a highly malignant human brain neoplasm with limited therapeutic options. GBMs display a deregulated apoptotic pathway with high levels of the antiapoptotic Bcl-2 family of proteins and overt activity of the phosphatidylinositol 3-kinase (PI3K) signaling pathway. Therefore, combined interference of the PI3K pathway and the Bcl-2 family of proteins is a reasonable therapeutic strategy. ABT-263 (Navitoclax), an orally available small-molecule Bcl-2 inhibitor, and GDC-0941, a PI3K inhibitor, were used to treat established glioblastoma and glioblastoma neurosphere cells, alone or in combination. Although GDC-0941 alone had a modest effect on cell viability, treatment with ABT-263 displayed a marked reduction of cell viability and induction of apoptotic cell death. Moreover, combinatorial therapy using ABT-263 and GDC-0941 showed an enhanced effect, with a further decrease in cellular viability. Furthermore, combination treatment abrogated the ability of stem cell-like glioma cells to form neurospheres. ABT-263 and GDC-0941, in combination, resulted in a consistent and significant increase of Annexin V positive cells and loss of mitochondrial membrane potential compared with either monotherapy. The combination treatment led to enhanced cleavage of both initiator and effector caspases. Mechanistically, GDC-0941 depleted pAKT (Serine 473) levels and suppressed Mcl-1 protein levels, lowering the threshold for the cytotoxic actions of ABT-263. GDC-0941 decreased Mcl-1 in a posttranslational manner and significantly decreased the half-life of Mcl-1 protein. Ectopic expression of human Mcl-1 mitigated apoptotic cell death induced by the drug combination. Furthermore, GDC-0941 modulated the phosphorylation status of BAD, thereby further enhancing ABT-263-mediated cell death. Combination therapy with ABT-263 and GDC-0941 has novel therapeutic potential by specifically targeting aberrantly active, deregulated pathways in GBM, overcoming

  16. 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

  17. 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.

  18. 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

  19. Cytotoxic activity of Justicia spicigera is inhibited by bcl-2 proto-oncogene and induces apoptosis in a cell cycle dependent fashion.

    PubMed

    Cáceres-Cortés, J R; Cantú-Garza, F A; Mendoza-Mata, M T; Chavez-González, M A; Ramos-Mandujano, G; Zambrano-Ramírez, I R

    2001-12-01

    Identification of organic compounds from plants is of clinical significance because of the effect that they might have in patients with haematopoietic disorders. We studied the effect of the plant extract Justicia spicigera (Acanthaceae) in different haematopoietic cells: human leukaemic cell lines, umbilical cord blood cells, and mouse bone marrow cells. By examining colony formation and performing the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay it was shown that the plant extract of Justicia spicigera contains cytotoxic factors for leukaemic cells and has no proliferative activity on normal haematopoietic progenitor cells. Our results show that this plant extract induces apoptosis in the human leukaemia cell line TF-1, but not in the bcl-2 transfectant cell line TB-1. Similar results were obtained using a haemopoietic cell line 32D and 32DBcl2. The cultures of umbilical cord blood cells and mouse bone marrow that contain granulocyte-macrophage colony-stimulating factor (GM-CSF) do not proliferate or become terminally differentiated in the presence of the infusion of Justicia spicigera. GM-CSF that acts by abrogating programmed cell death is not sufficient to inhibit the apoptotic stimulus in TF-1 and 32D cells. Moreover mouse fibroblasts (3T3) and two cervical carcinoma cell lines CALO and INBL, undergo apoptosis in the presence of different concentrations of an infusion from the plant. Our data show that there is a strong correlation between the cytotoxic effect and cell proliferation. Together, these results indicate that the plant infusion of Justicia spicigera does not contain any haematopoietic activity, induces apoptosis inhibited by bcl-2 and is linked to cell proliferation. Copyright 2001 John Wiley & Sons, Ltd.

  20. 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.

  1. 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.

  2. 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.

  3. Effects of methylglyoxal and glyoxalase I inhibition on breast cancer cells proliferation, invasion, and apoptosis through modulation of MAPKs, MMP9, and Bcl-2.

    PubMed

    Guo, Yi; Zhang, Yuning; Yang, Xunjun; Lu, Panpan; Yan, Xijuan; Xiao, Fanglan; Zhou, Huaibin; Wen, Chaowei; Shi, Mengru; Lu, Jianxin; Meng, Qing H

    2016-01-01

    Emerging evidence indicates that methylglyoxal (MG) can inhibit tumorigenesis. Glyoxalase I (GLOI), a MG degradation enzyme, is implicated in the progression of human malignancies. However, little is known about the roles of MG and GLOI in breast cancer. Our purpose was to investigate the anticancer effects of MG and inhibition of GLOI on breast cancer cells and the underlying mechanisms of these effects. Our findings demonstrate that cell viability, migration, invasion, colony formation, and tubule formation were significantly restrained by addition of MG or inhibition of GLOI, while apoptosis was significantly increased. Furthermore, the expression of p-JNK, p-ERK, and p-p38 was markedly upregulated by addition of MG or inhibition of GLOI, whereas MMP-9 and Bcl-2 expression levels were dramatically decreased. These effects were augmented by combined treatment with MG and inhibition of GLOI. Collectively, these data indicate that MG or inhibition of GLOI induces anticancer effects in breast cancer cells and that these effects are potentiated by combination of the 2. These effects were modulated by activation of the MAPK family and downregulation of Bcl-2 and MMP-9. These findings may provide a new approach for the treatment of breast cancer.

  4. ELF-MF attenuates quercetin-induced apoptosis in K562 cells through modulating the expression of Bcl-2 family proteins.

    PubMed

    Brisdelli, Fabrizia; Bennato, Francesca; Bozzi, Argante; Cinque, Benedetta; Mancini, Fabrizio; Iorio, Roberto

    2014-12-01

    This study investigated the effects of sinusoidal ELF-MF (1 mT; 50 Hz) on the apoptosis induced by four different compounds, namely vinblastine, etoposide, quercetin, and resveratrol, in human K562 chronic myeloid leukemia cells. The exposure to ELF-MF did not affect growth and viability of untreated K562 cells and did not influence the anti-proliferative effects of resveratrol, vinblastine, and etoposide. On the contrary, in quercetin-treated cells, exposure to ELF-MF significantly reduced the percentage of apoptotic cells and the caspase-3 activity and modified the cell cycle profile especially after 48 h of exposure. In addition, the simultaneous treatments for 24 h with quercetin plus ELF-MF increased Bcl-2 protein expression and prevented quercetin-induced downregulation of Mcl-1 and Bcl-xL. Finally, an increase of HSP70 expression was also observed after prolonged ELF-MF treatment. The ELF-MF-dependent modulation of the expression of anti-apoptotic Bcl-2 family and Hsp70 proteins could act as a pro-survival mechanism in K562 cells.

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

    PubMed Central

    Kvansakul, M; Hinds, M G

    2013-01-01

    Intrinsic apoptosis in mammals is regulated by protein–protein interactions among the B-cell lymphoma-2 (Bcl-2) family. The sequences, structures and binding specificity between pro-survival Bcl-2 proteins and their pro-apoptotic Bcl-2 homology 3 motif only (BH3-only) protein antagonists are now well understood. In contrast, our understanding of the mode of action of Bax and Bak, the two necessary proteins for apoptosis is incomplete. Bax and Bak are isostructural with pro-survival Bcl-2 proteins and also interact with BH3-only proteins, albeit weakly. Two sites have been identified; the in-groove interaction analogous to the pro-survival BH3-only interaction and a site on the opposite molecular face. Interaction of Bax or Bak with activator BH3-only proteins and mitochondrial membranes triggers a series of ill-defined conformational changes initiating their oligomerization and mitochondrial outer membrane permeabilization. Many actions of the mammalian pro-survival Bcl-2 family are mimicked by viruses. By expressing proteins mimicking mammalian pro-survival Bcl-2 family proteins, viruses neutralize death-inducing members of the Bcl-2 family and evade host cell apoptosis during replication. Remarkably, structural elements are preserved in viral Bcl-2 proteins even though there is in many cases little discernible sequence conservation with their mammalian counterparts. Some viral Bcl-2 proteins are dimeric, but they have distinct structures to those observed for mammalian Bcl-2 proteins. Furthermore, viral Bcl-2 proteins modulate innate immune responses regulated by NF-κB through an interface separate from the canonical BH3-binding groove. Our increasing structural understanding of the viral Bcl-2 proteins is leading to new insights in the cellular Bcl-2 network by exploring potential alternate functional modes in the cellular context. We compare the cellular and viral Bcl-2 proteins and discuss how alterations in their structure, sequence and binding specificity

  6. Betulinic acid decreases expression of bcl-2 and cyclin D1, inhibits proliferation, migration and induces apoptosis in cancer cells.

    PubMed

    Rzeski, Wojciech; Stepulak, Andrzej; Szymański, Marek; Sifringer, Marco; Kaczor, Józef; Wejksza, Katarzyna; Zdzisińska, Barbara; Kandefer-Szerszeń, Martyna

    2006-10-01

    Betulinic acid (BA) is a pentacyclic triterpene found in many plant species, among others in the bark of white birch Betula alba. BA was reported to display a wide range of biological effects, including antiviral, antiparasitic, antibacterial and anti-inflammatory activities, and in particular to inhibit growth of cancer cells. The aim of the study was further in vitro characterization of BA anticancer activity. In this study, we demonstrated a remarkable antiproliferative effect of BA in all tested tumor cell cultures including neuroblastoma, rabdomyosarcoma-medulloblastoma, glioma, thyroid, breast, lung and colon carcinoma, leukemia and multiple myeloma, as well as in primary cultures isolated from ovarian carcinoma, cervical carcinoma and glioblastoma multiforme. Furthermore, we have shown that BA decreased cancer cell motility and induced apoptotic cell death. We also observed decrease of bcl2 and cyclin D1 genes expression, and increase of bax gene expression after betulinic acid treatment. These findings demonstrate the anticancer potential of betulinic acid and suggest that it may be taken into account as a supportive agent in the treatment of cancers with different tissue origin.

  7. 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

  8. 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

  9. Tumor growth reduction in Walker 256 tumor-bearing rats performing anaerobic exercise: participation of Bcl-2, Bax, apoptosis, and peroxidation.

    PubMed

    de Lima, Carina; Alves, Luciana; Iagher, Fabíola; Machado, Andressa Franzoi; Kryczyk, Marcelo; Yamazaki, Ricardo Key; Brito, Gleisson Alisson Pereira; Nunes, Everson Araújo; Naliwaiko, Katya; Fernandes, Luiz Cláudio

    2011-08-01

    Physical activity has been used in cancer prevention and treatment. In this study, we investigated some of the mechanisms by which anaerobic exercise reduces tumor growth. To do so, rats were trained for 8 weeks. Training consisted of jumping in a swimming pool for ten 30-s sets, with a load that was 50% of body weight attached to the back, 4 times per week. At the sixth week, anaerobic exercise trained rats (EX group) were inoculated with a suspension of Walker 256 tumor cells. Tumor weight, apoptotic tumor cells, tumor Bax and Bcl-2 protein expression, tumor lipid peroxidation, and tumor cell proliferation ex vivo were evaluated. Tumor weight was significantly lower in the EX group (∼30%) than in rats that did not undergo training (sedentary group) (p < 0.05). Apoptosis in the tumor cells of EX rats was 2-fold higher than in the tumor cells of sedentary rats; in addition, Bax expression increased by 10% and Bcl-2 decreased by 13% in EX rats. Lipid peroxidation was 4-fold higher in the tumor cells of EX rats than in those of sedentary rats (p < 0.05). Tumor cell proliferation ex vivo was 29% lower in the EX group than in the sedentary group (p < 0.05). In conclusion, Walker 256 tumor-bearing exercised rats presented more tumor cell apoptosis, a higher tumor content of lipid peroxides, pro-apoptotic protein expression balance, and reduced tumor weight and cell proliferation ex vivo, compared with sedentary rats. These events, together, account for the lower tumor growth we observed in the EX rats.

  10. Estrogen Regulation of Anti-Apoptotic Bcl-2 Family Member Mcl-1 Expression in Breast Cancer Cells

    PubMed Central

    Schacter, Jennifer L.; Henson, Elizabeth S.; Gibson, Spencer B.

    2014-01-01

    Estrogen is implicated as an important factor in stimulating breast cancer cell proliferation, and presence of estrogen receptor (ER) is an indication of a good prognosis in breast cancer patients. Mcl-1 is an anti-apoptotic Bcl-2 family member that is often over expressed in breast tumors, correlating with poor survival. In breast cancer, it was been previously shown that epidermal growth factor receptors up-regulate Mcl-1 but the role of estrogen in increasing Mcl-1 expression was unknown. In ERα positive cell lines MCF-7 and ZR-75, estrogen treatment increased Mcl-1 expression at both the protein and mRNA level. In two ERα negative cell lines, SK-BR-3 and MDA-MB-231, estrogen failed to increase in Mcl-1 protein expression. We found that ERα antagonists decreased estrogen mediated Mcl-1 expression at both the protein and mRNA level. Upon knockdown of ERα, Mcl-1 mRNA expression after estrogen treatment was also decreased. We also found that ERα binds to the Mcl-1 promoter at a region upstream of the translation start site containing a half ERE site. Streptavidin-pull down assay showed that both ERα and transcription factor Sp1 bind to this region. These results suggest that estrogen is involved in regulating Mcl-1 expression specifically through a mechanism involving ERα. PMID:24971890

  11. miR-21 inhibitor suppresses proliferation and migration of nasopharyngeal carcinoma cells through down-regulation of BCL2 expression.

    PubMed

    Li, Yumei; Yan, Limei; Zhang, Wenyu; Wang, Hui; Chen, Wei; Hu, Nan; Ou, Hesheng

    2014-01-01

    This study is to investigate the expression of miR-21 in nasopharyngeal carcinoma (NPC) cells, and the effect of miR-21 in the biological behavior and expression of B-cell lymphoma 2 (BCL2) in NPC cells. Paired NPC and adjacent non-tumor tissues were obtained from 53 patients who underwent primary surgical resection of NPC tissues. Luciferase reporter assay was performed to test whether BCL2 is a direct target of miR-21. Methylthiazolyl blue tetrazolium assay and colony assay were used to evaluate the effect of miR-21 on NPC cell proliferation. Transwell and wound-healing assays were carried out to test the effect of low expression of miR-21 on cancer cell migration and invasion. QRT-PCR and Western blotting were used to measure the levels of mRNA and protein expression, respectively. Tumor tissues showed a positive correlation between the levels of miR-21 and BCL2 protein expression. Cells transfected with miR-21 inhibitor healed slower compared the control (P < 0.05). In addition, cell migration was notably inhibited by the down-regulation of miR-21 in vitro (P < 0.05). The reduction in miR-21 expression showed a remarkable effect on the biological behavior of NPC cell clone formation (P < 0.05). Low expression of miR-21 by transfection with miRNA expression plasmid led to a decrease in BCL2 expression, which was accompanied by reduced migration and proliferation of the cancer cells. Our results demonstrated that miR-21 inhibitor down-regulated BCL2 expression level, suggesting that BCL2 might be a target gene for the initiation and development of NPC cells.

  12. SAHA treatment overcomes the anti-apoptotic effects of Bcl-2 and is associated with the formation of mature PML nuclear bodies in human leukemic U937 cells.

    PubMed

    Lee, Jee Suk; Jeong, Seung Hun; Soung, Young Hwa; Kim, Tae Hyun; Choi, Hong Jo; Park, Bong Soo; Kwon, Taeg Kyu; Yoo, Young Hyun

    2009-09-14

    Bcl-2 protects tumor cells from the apoptotic effects of various antineoplastic agents. Increased expression of Bcl-2 has been associated with poor response to chemotherapy in various malignancies, including leukemia. Therefore, bypassing the resistance conferred by anti-apoptotic factors such as Bcl-2 represents an attractive therapeutic strategy against cancer cells, including leukemic cells. We undertook this study to examine whether SAHA (suberoylanilide hydroxamic acid) overcomes the resistance by Bcl-2 in human leukemic cells, with a specific focus on the involvement of PML-NBs. Experiments were conducted with Bcl-2-overexpressing human leukemic U937 cells. Since we previously demonstrated that overexpression of Bcl-2 attenuates resveratrol-induced apoptosis in human leukemic U937 cells, resveratrol-treated U937 cells were used as a negative control. The present study indicates that SAHA at 1-7 microM, the dose range known to induce apoptosis in various cancer cells, overcomes the anti-apoptotic effects of Bcl-2 in Bcl-2-overexpressing human leukemic U937 cells. Notably, we observed that SAHA-induced formation of mature promyelocytic leukemia (PML) nuclear bodies (NBs) correlates with overcoming the anti-apoptotic effects of Bcl-2 in human leukemic U937 cells. Thus, PML protein and the formation of mature PML-NBs could be considered as therapeutic targets that could help bypass the resistance to apoptosis conferred by Bcl-2. Elucidating exactly how PML regulates Bcl-2 will require further work.

  13. Targeted nano-delivery of novel omega-3 conjugate against hepatocellular carcinoma: Regulating COX-2/bcl-2 expression in an animal model.

    PubMed

    Khan, Azmat Ali; Alanazi, Amer M; Jabeen, Mumtaz; Hassan, Iftekhar; Bhat, Mashooq Ahmad

    2016-07-01

    The present approach enumerates the effectiveness of tuftsin tagged nano-liposome for the cytosolic transport of 2,6-di-isopropylphenol-linolenic acid conjugate against liver cancer in mice. Initially, the conjugate in its free form was examined for anticancer potential on HepG2 liver cancer cells. Induction of apoptosis and suppression of migration and adhesion of HepG2 cells confirmed the effectiveness of conjugate as an anticancer agent. After this, role of the conjugate entrapped in a nano-carrier was evaluated in animal model. The nano-formulation comprising of conjugate bearing tuftsin tagged liposome was firsly characterized and then its therapeutic effect was determined. The nano-formulation had 100-130nm size nanoparticles and showed sustained release of the conjugate in the surrounding milieu. The nano-formulation distinctly reduced the expression of COX-2, an important molecule that is vastly expressed in hepatocellular carcinoma. The utilization of in-house engineered nano-formulation was also successful in significantly up-regulating Bax and down-regulating bcl-2 gene expression eventually helping in better survival of treated mice. Histopathological analysis also revealed positive recovery of the general architecture and the violent death of cancer cells by apoptosis at tumor specific site. The site specific delivery of conjugate entrapped in tuftsin tagged liposomes was highly safe as well as efficaceous. Nano-formulation based approach showed a visible chemotherapeutic effect on liver cancer progression in experimental mice thereby making it a potential candidate for treatment of liver cancer in clinical settings.

  14. 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

  15. Short interfering RNA directed against the GOLPH3 gene enhances the effect of chemotherapy against oral squamous cell carcinoma by regulating Caspase3, Bcl2 and cytochrome-c expression

    PubMed Central

    Cui, Guo-Hui; Li, Wen-Xin; Lin, Zhi-Yong; Zhang, Wei-Qun; Hu, Zhao-Hui; Wang, Li

    2015-01-01

    Growing evidence reported that Golgi phosphoprotein 3 (GOLPH3) was involved in the progression of several human cancers. To determine whether knockout of GOLPH3 enhances the effect of Chemotherapy against cell growth of oral squamous cell carcinoma in vitro. OSCC cells were transfected with Golph3 plasmid, Golph3-RNAi and the relative control plasmids. Transfected Tca-8113 cells treated with cis-Dichlorodiamineplatinum (DDP; 0, 0.05, 0.25, 1.25, 6.25 and 31.25 ug/ml) or Paclitaxe (0, 2, 10, 50, 250 and 1250 nM) or Adriamycin (0, 0.25, 0.5, 1, 2 and 4 ug/ml) for 24 h, respectively, was determined using MTT assay. Apoptosis-related protein expression Cytochrome-C, Caspase3 and Bcl-2 was analyzed by RT-PCR and western blots. Result of MTT showed that Golph3-RNAi transfected Tca-8113 cells enhanced the effect of chemotherapy, and the effect was strengthened with the increasing concentration of drugs, and the Golph3 plasmid transfected Tca-8113 cells showed the opposite effect. RT-PCR and western blots assays revealed that expression of cytochrome-C and caspase3 were up-regulated, while Bcl-2 expression was down-regulated in Golph3-RNAi transfected Tca-8113 cells. Taken together, this study demonstrated that GOLPH3 had potent pro-tumor growth and decreased the effect of Chemotherapy, and its mechanism is primarily via cell anti-apoptosis, down-regulating the expression of cytochrome-C and caspase3, up-regulating Bcl-2 expression. PMID:26550222

  16. Bax expression remains unchanged following antisense treatment directed against BCL-2.

    PubMed

    Rubenstein, Marvin; Hollowell, Courtney M P; Guinan, Patrick

    2011-09-01

    Antisense oligonucleotides (oligos) have been evaluated in both in vivo and in vitro prostate cancer models. Although most contain a single mRNA binding site, our laboratory has also evaluated bispecific types directed toward two proteins. This study evaluates the inhibition of in vitro propagating LNCaP cells employing mono- and bispecific oligos directed against bcl-2 [the second binding site was directed against the epidermal growth factor receptor (EGFR)]. Employing RT-PCR, the expression of two apoptosis regulating proteins, bcl-2 and non-targeted bax, was then evaluated. LNCaP prostate tumor cells were initially incubated for 24 h in the presence of oligos (6.25 μM) directed against bcl-2 and compared to lipofectin containing controls. Comparable and significant growth inhibition was produced by both mono- and bispecific forms. Employing RT-PCR to determine the expression of bcl-2, we found that the greatest amount of mRNA suppression approached 100% for each oligo type: monospecific MR4 (directed only against bcl-2), 100%; and bispecifics MR24 and MR42, 86 and 100%, respectively. We conclude, based upon both inhibition of in vitro growth and bcl-2 expression, that bispecific antisense oligos directed against EGFR and bcl-2 mRNAs are at least as effective as a monospecific directed solely toward bcl-2. In an effort to determine a compensatory response by cells evading apoptosis in the presence of bcl-2 suppression, the levels of mRNA encoding the non-targeted apoptosis activating protein bax were evaluated. Non-targeted protein suppression by these bispecifics has previously been demonstrated against prostate-specific membrane antigen (PSMA). However, in contrast to effects against bcl-2 and PSMA, no significant alteration in bax expression was produced by either oligo type. In LNCaP cells, bcl-2 suppression does not influence bax expression and, at least for this protein, there is no compensatory change in bax expression regulating apoptosis at this level

  17. Apoptosis induced by paclitaxel via Bcl-2, Bax and caspases 3 and 9 activation in NB4 human leukaemia cells is not modulated by ERK inhibition.

    PubMed

    Morales-Cano, Daniel; Calviño, Eva; Rubio, Virginia; Herráez, Angel; Sancho, Pilar; Tejedor, M Cristina; Diez, José C

    2013-11-01

    We have studied the role of pivotal bio-molecules involved in signalling of cytotoxic effects induced by paclitaxel (Ptx) on acute promyelocytic human leukaemia NB4 cells. A time-dependent increase in cell death and DNA cleavage was observed after 30μM Ptx treatment. Cell death induction by Ptx proceeds mainly as programmed cell death as shown by annexin V-FITC, reaching up to 30% of apoptotic cells after 24h. Significant reductions of p53, changes in Bax and Bcl-2 and activation of caspases 3 and 9 were observed as the treatment was applied for long times. Ptx treatments produced NFkB depletion with expression levels abolished at 19h what could be involved in reduction of survival signals. Phosphorylation of intracellular kinases showed that pERK1/2 decreased significantly at 19h of Ptx treatment. When these cells were preincubated for 90min with 20μM PD98059, 2'-amino-3'-methoxyflavone, an inhibitor of ERK phosphorylation, a slight reduction of cell viability was observed in comparison to that produced by Ptx alone. Pretreatment with PD98059 neither activated caspases nor significantly increased the apoptotic effect of Ptx. Taken together, our data reveal that the inhibition of ERK phosphorylation does not seem to be an essential pathway for bursting an increased induction of apoptosis by Ptx. Decrease of p53 and Bcl-2, fragmentation of DNA, increase of Bax and, finally, activation of caspases 3 and 9 in NB4 leukaemia cells make the apoptotic process induced by Ptx irreversible. Application of Ptx in leukaemia cells shows therefore a promising potential with particular effects on different leukaemia cell types.

  18. 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.

  19. Fish oil administration mediates apoptosis of Walker 256 tumor cells by modulation of p53, Bcl-2, caspase-7 and caspase-3 protein expression.

    PubMed

    Borghetti, Gina; Yamaguchi, Adriana Aya; Aikawa, Julia; Yamazaki, Ricardo Key; de Brito, Gleisson Alisson Pereira; Fernandes, Luiz Claudio

    2015-08-25

    Several studies have been shown pro-apoptotic effects of fish oil (FO), rich in n-3 polyunsaturated fatty acids (n-3 PUFA) on cancer cells. Nevertheless, few in vivo experiments have provided data of its ability on apoptosis protein expression in tumor tissue. Thus, in this study we investigate the effect of FO supplementation on apoptosis protein expression in Walker 256 tumor bearing rats. Male Wistar rats were randomly assigned to three groups: fed with regular chow (W); fed regular chow supplemented with FO (WFO) or coconut fat (WCO) (1 g/kg body weight/daily). After thirty days, all animals were inoculated subcutaneously with Walker 256 tumor cells. Protein expression was done by western blotting in Walker 256 tumor tissue samples. FO decreased the Bcl-2/Bax ratio (p < 0.05) and increased the p53 (p < 0.05), cleaved caspase-7 (p < 0.05) and cleaved caspase-3 (p < 0.05) in Walker 256 tumor tissue. Our data suggest that the pro-apoptotic effect of FO in Walker 256 tumor is related with specifics cleaved caspases.

  20. 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

  1. PLCgamma2 regulates Bcl-2 levels and is required for survival rather than differentiation of marginal zone and follicular B cells.

    PubMed

    Bell, Sarah E; Vigorito, Elena; McAdam, Simon; Reynolds, Helen M; Caraux, Anouk; Colucci, Francesco; Turner, Martin

    2004-08-01

    B cells from phospholipase C (PLC)gamma2-deficient mice express reduced levels of the pro-survival protein Bcl-2 and show a defect in the development of transitional T3 and marginal zone (MZ) B cells that reflects reduced B cell survival. Introduction of a bcl-2 transgene restored the numbers of MZ, T3 and follicular B cells in PLCgamma2(-/-) mice. Restricting the B cell repertoire in PLCgamma2-deficient mice by the introduction of a BCR transgene resulted in a striking reduction in the number of IgM-positive B cells and a paucity of IgD-expressing cells in the spleen which was also rescued by the bcl-2 transgene. BCR-stimulated ERK and IkappaBalpha phosphorylation were PLCgamma2 dependent, while calcium flux was reduced, but not abrogated, in the absence of PLCgamma2, suggesting an ancillary role for PLCgamma1. The bcl-2 transgene rescued development of PLCgamma2(-/-) B cells and serum IgM levels but did not restore BCR-mediated signaling, proliferation or serum IgG3 levels. These data suggest that PLCgamma2 performs a critical role in B cell development through regulation of survival rather than differentiation.

  2. 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

  3. 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

  4. 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.

  5. [Effects of different ways in repairing scrotum of pigs with full-thickness burn on apoptosis and bcl-2 protein expression of spermatogenic cells].

    PubMed

    Tang, Xiu-jun; Wei, Zai-rong; Sun, Guang-feng; Huang, Zhao-hui; Zhu, Jing-jing; Deng, Cheng-liang; Wang, Da-li

    2012-04-01

    To observe the effects of different ways in repairing scrotum of pigs with full-thickness burn on spermatogenesis of testis. Twenty male Guizhou miniature pigs were divided into normal control (NC), natural-healing (NH), flap-repairing (FR), and skin-grafting (SG) groups according to the random number table, with 5 pigs in each group. Pigs in NC group were not subjected to any injury. Scrotum of pigs in the latter three groups were inflicted with full-thickness burn. Wounds in NH group healed naturally. Wounds in FR group were repaired with inguinal region flap, and those in SG group with full-thickness skin from lower abdomen. Appearance of scrotum in the latter three groups was observed right after injury, and three months post injury or surgery (PIM or PSM). Specimens of testes of pigs in the latter three groups were obtained in PIM or PSM 3 to detect apoptosis of spermatogenic cells with TUNEL, and bcl-2 protein expression with immunohistochemistry. The same indexes were observed and determined in pigs of NC group. Data were processed with one-way analysis of variance and LSD test. (1) Scrotum of pigs in NC group had skin folds with contraction function. Scrotum of pigs became hard with a leathery appearance right after burn in the other three groups. In PIM or PSM 3, wounds of pigs in NH group healed with scar, and the testes were squeezed into inguinal region. Scrotal skin of pigs in FR group was thick with testes in the scrotum, and that of pigs in SG group was thin with testes in the scrotum. (2) Spermatogenic cells in each level in NC group were arranged regularly, with few apoptotic spermatocytes and spermatoblasts. In NH, FR, and SG groups, seminiferous epithelium was thinner with most of the spermatogenic cells showing apoptosis, and they were mainly spermatogonia and spermatocytes. Apoptotic index of spermatogenic cells in NH, FR, SG, and NC groups was respectively (46.3 ± 3.3)%, (40.9 ± 3.5)%, (20.6 ± 2.3)%, (7.5 ± 1.9)%, and the difference among

  6. PRIMA-1 induces caspase-mediated apoptosis in acute promyelocytic leukemia NB4 cells by inhibition of nuclear factor-κB and downregulation of Bcl-2, XIAP, and c-Myc.

    PubMed

    Farhadi, Elham; Safa, Majid; Sharifi, Ali M; Bashash, Davood

    2017-01-01

    Restoration of p53 function triggers cell death and eliminates tumors in vivo. Identification of p53-reactivating small molecules such as PRIMA-1 holds promise for effective new anticancer therapies. Here, we investigated the effects of small molecule PRIMA-1 on cell viability and expression of p53-regulated genes and proteins in the acute promyelocytic leukemia-derived NB4 cell line. Our results showed that PRIMA-1 had antileukemic properties in acute promyelocytic leukemia-derived NB4 cells. PRIMA-1-triggered apoptosis in a dose-dependent and time-dependent manner as indicated by the MTT assay and annexin-V staining. Apoptosis induction by PRIMA-1 was associated with caspase-9, caspase-7 activation and PARP cleavage. p21 protein expression was increased after PRIMA-1 treatment and real-time PCR analysis of proapoptotic p53 target genes indicated upregulation of Bax and Noxa. Western blot analysis showed that IκBα phosphorylation and its degradation were inhibited by PRIMA-1. Moreover, protein expression of nuclear factor-κB-regulated antiapoptotic (Bcl-2 and XIAP) and proliferative (c-Myc) gene products was decreased. Importantly, PRIMA-1 did not show any significant apoptotic effect in normal human peripheral blood mononuclear cells. These in-vitro studies imply that p53 reactivation by small compounds may become a novel anticancer therapy in acute promyelocytic leukemia.

  7. ECP-treated lymphocytes of chronic graft-versus-host disease patients undergo apoptosis which involves both the Fas/FasL system and the Bcl-2 protein family.

    PubMed

    Di Renzo, M; Rubegni, P; Sbano, P; Cuccia, A; Castagnini, C; Pompella, G; Pasqui, A L; Capecchi, P L; Auteri, A; Laghi Pasini, F; Fimiani, M

    2003-09-01

    Chronic graft-versus-host disease (cGVHD) is a severe and frequent complication of allogenic bone marrow transplantation which is often treated with extracorporeal photochemotherapy (ECP) with a positive clinical outcome in patients resistant to conventional protocols. The mechanism of action of ECP has not been fully elucidated, although several authors have reported that it is able to induce apoptosis. Using samples obtained from ten cGVHD patients, we sought to determine whether lymphocytes treated with ECP underwent apoptosis and, above all, the mechanisms involved. Lymphocytes at four stages were isolated: immediately before ECP, from the last buffy coat collected, after UV irradiation prior to reinfusion, and the day after ECP. When cultured for 48 h, lymphocytes treated with ECP underwent accelerated apoptosis (tested as annexin V binding cells and as intracellular histone-associated DNA fragments) in comparison with lymphocytes from the other samples. This enhanced programmed cell death could not be prevented by IL-2. Immediately after isolation, there was no difference in Bcl-2 or bax expression among the four different samples, or in Fas and FasL mRNA. However, when cultured, lymphocytes treated with ECP showed a rapid downregulation of Bcl-2, an upregulation of bax with an increased bax/Bcl-2 ratio, a decrease in bcl-2 mRNA and an increase in Fas. No changes were detectable in lymphocytes from the other samples. IL-2 and TNF-alpha production was not significantly different among lymphocytes from the four samples. In conclusion, in patients affected by cGVHD, ECP induced apoptosis of lymphocytes with the involvement of both the Fas/FasL system and the Bcl-2 protein family.

  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. Expression of the apoptosis-related genes BCL-2 and BAD in human breast carcinoma and their associated relationship with chemosensitivity.

    PubMed

    Yu, Bing; Sun, Xin; Shen, Hong-yan; Gao, Feng; Fan, Yuan-ming; Sun, Zhi-jun

    2010-08-07

    To evaluate the expression of BCL-2 and BAD genes in tissues of breast carcinoma and investigate the relationship between the expression of BCL-2 and BAD in breast cancer cells with chemosensitivity. Immunohistochemical technique was used to detect the expression of BCL-2, BAD in 10 normal breast tissues, 10 breast fibroadenoma tissues, 40 youth human breast carcinoma tissues, 40 menopause human breast carcinoma tissues. And to detect the expression of ER, PR in 80 human breast carcinoma tissues. 20 Surgical samples of breast cancer, diagnosed by pathology, were obtained from The First Affiliated Hospital of Chongqing Medical University. The cancer sample cells were cultured separately in the incubator at 37 degrees C, 5% CO2 in vitro. The rate of inhibition of cancer cells in 4 kinds of anticancer drugs-- Epirubicin Adriamycin (EADM),5-Fluorouracil (5-Fu), Navelbine(NVB) and Diaminedichloroplatinum (DDP), were assayed by MTT method. The expression of BCL-2, BAD genes in young human breast carcinoma tissues were lower than that in menopause human breast carcinoma tissues (P < 0.05). There was a negative correlation between the positive expression rate of BCL-2 and histologic grade or the lymph node metastasis (P < 0.05). There was a positive correlation between the expression rates of BCL-2 and of ER, PR (P < 0.05). The expression of BAD had no relationship with the expression of ER, PR, histologic grade and the lymph node metastasis(P = NS). Sensitivity rates of 20 breast cancer cells in 0.1 x PPC within 48 h in vitro were 30% EADM,20% 5-Fu,45% NVB and 25% DDP. Respectively, the rate of inhibition of EADM,5- Fu, NVB and DDP were significantly higher in the BCL-2 negative cancer cells than in the BCL-2 positive cancer cells. A negative correlation was found between expression of BCL-2 and chemosensitivity for all the 4 anticancer drugs. The inhibition rates of EADM and NVB were significantly lower in the BAD negative cancer cells than in the BAD positive cancer

  10. Apoptosis is augmented in high-grade serous ovarian cancer by the combined inhibition of Bcl-2/Bcl-xL and PARP

    PubMed Central

    Yokoyama, Takuhei; Kohn, Elise C.; Brill, Ethan; Lee, Jung-Min

    2017-01-01

    The aim of our study was to evaluate possible synergistic cytotoxic effects of the combination treatment with the BH3-mimetic ABT-263 and the PARP inhibitor BMN 673 in high-grade serous ovarian cancer (HGSOC) cells using clinically achievable concentrations of each drug. In vitro cytotoxic effects of ABT-263 and BMN 673 were assessed by XTT assay in three HGSOC cell lines: OVCAR3, OVCAR8, and OV90 cells. Combination index values and synergy/antagonism volumes were used to determine synergy. The drug effects on DNA damage accumulation, cell cycle progression, apoptosis induction, and expression levels of Bcl-2 family proteins were examined to dissect molecular mechanisms. The combination treatment synergistically decreased cell viability in a concentration- and time-dependent manner in all cell lines; combination index values were <0.9 and synergy/antagonism volumes were >100 after 72 h of treatment. Clinically achievable concentrations of ABT-263 2 µM and BMN 673 25 nM were used to investigate mechanisms. No increase in γ-H2AX foci formation was observed with addition of ABT-263 to BMN 673 treatment. The combination treatment increased the sub-G1 and Annexin V-positive cell populations after 48 h compared with the control and each monotherapy. It also induced greater caspase-3/7 activity and PARP cleavage. ABT-263 alone and in combination with BMN 673 induced expression levels of Bim, a pro-apoptotic protein. In conclusion, the ABT-263 and BMN 673 combination resulted in synergistic cytotoxic effects against HGSOC cells through greater induction of apoptosis. This may be a novel therapeutic strategy for HGSOC. PMID:28350129

  11. 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

  12. Bcl-2 regulation of the inositol 1,4,5-trisphosphate receptor and calcium signaling in normal and malignant lymphocytes: potential new target for cancer treatment.

    PubMed

    Greenberg, Edward F; Lavik, Andrew R; Distelhorst, Clark W

    2014-10-01

    The anti-apoptotic protein Bcl-2 is a versatile regulator of cell survival. Its interactions with its own pro-apoptotic family members are widely recognized for their role in promoting the survival of cancer cells. These interactions are thus being targeted for cancer treatment. Less widely recognized is the interaction of Bcl-2 with the inositol 1,4,5-trisphosphate receptor (InsP3R), an InsP3-gated Ca(2+) channel located on the endoplasmic reticulum. The nature of this interaction, the mechanism by which it controls Ca(2+) release from the ER, its role in T-cell development and survival, and the possibility of targeting it as a novel cancer treatment strategy are summarized in this review. This article is part of a Special Issue entitled: Calcium signaling in health and disease. Guest Editors: Geert Bultynck, Jacques Haiech, Claus W. Heizmann, Joachim Krebs, and Marc Moreau.

  13. Expression of pro-apoptotic Bax and anti-apoptotic Bcl-2 proteins in human retinoblastoma.

    PubMed

    Singh, Lata; Pushker, Neelam; Saini, Neeru; Sen, Seema; Sharma, Anjana; Bakhshi, Sameer; Chawla, Bhavna; Kashyap, Seema

    2015-04-01

    Regulation of apoptosis is a complex process that involves a number of genes, including Bcl-2, Bcl-x, Bax and other Bcl-2 family members. The aim of the present study is to assess the expression of Bcl- 2 and Bax in retinoblastoma, and correlate them with clinical and histopathological parameters. The expression of Bcl-2 and Bax proteins were examined using immunohistochemistry, Western blotting and reverse transcriptase-polymerase chain reaction in a series of 60 prospective cases of primary retinoblastoma tissues. Immunohistochemistry showed expression of Bcl-2 in 40/60 (66.6%), whereas Bax expression was found only in 18/60 (30%) cases, and these correlated with mRNA expression. The Western blotting results also correlated well with the immunohistochemical expression of Bcl-2 (25 kDa) and Bax (21 kDa) proteins. Bcl-2 was expressed in 96% (24/25) of invasive tumours and in 45.7% (16/35) of non-invasive tumours. Expression of Bcl-2 significantly correlated with tumour invasiveness (P = 0.0274) and poor differentiation (P = 0.0163), whereas loss of Bax correlated with massive choroidal invasion and Pathological Tumor-Node-Metastasis (pTNM) (P = 0.0341). However, no correlation was found between Bax and Bcl-2 expression. Our findings suggest that these apoptotic regulatory proteins may serve as poor prognostic markers and can be used as a therapeutic target for the treatment of invasive retinoblastoma. Further functional studies are required to explore the role of Bax and Bcl-2 in retinoblastoma. © 2014 Royal Australian and New Zealand College of Ophthalmologists.

  14. 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.

  15. 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.

  16. B cell lymphoma-2 (BCL-2) homology domain 3 (BH3) mimetics demonstrate differential activities dependent upon the functional repertoire of pro- and anti-apoptotic BCL-2 family proteins.

    PubMed

    Renault, Thibaud T; Elkholi, Rana; Bharti, Archana; Chipuk, Jerry E

    2014-09-19

    The B cell lymphoma-2 (BCL-2) family is the key mediator of cellular sensitivity to apoptosis during pharmacological interventions for numerous human pathologies, including cancer. There is tremendous interest to understand how the proapoptotic BCL-2 effector members (e.g. BCL-2-associated X protein, BAX) cooperate with the BCL-2 homology domain only (BH3-only) subclass (e.g. BCL-2 interacting mediator of death, BIM; BCL-2 interacting-domain death agonist, BID) to induce mitochondrial outer membrane permeabilization (MOMP) and apoptosis and whether these mechanisms may be pharmacologically exploited to enhance the killing of cancer cells. Indeed, small molecule inhibitors of the anti-apoptotic BCL-2 family members have been designed rationally. However, the success of these "BH3 mimetics" in the clinic has been limited, likely due to an incomplete understanding of how these drugs function in the presence of multiple BCL-2 family members. To increase our mechanistic understanding of how BH3 mimetics cooperate with multiple BCL-2 family members in vitro, we directly compared the activity of several BH3-mimetic compounds (i.e. ABT-263, ABT-737, GX15-070, HA14.1, TW-37) in biochemically defined large unilamellar vesicle model systems that faithfully recapitulate BAX-dependent mitochondrial outer membrane permeabilization. Our investigations revealed that the presence of BAX, BID, and BIM differentially regulated the ability of BH3 mimetics to derepress proapoptotic molecules from anti-apoptotic proteins. Using mitochondria loaded with fluorescent BH3 peptides and cells treated with inducers of cell death, these differences were supported. Together, these data suggest that although the presence of anti-apoptotic BCL-2 proteins primarily dictates cellular sensitivity to BH3 mimetics, additional specificity is conferred by proapoptotic BCL-2 proteins. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

  17. Association of Genetic Markers in the BCL-2 Family of Apoptosis-Related Genes with Endometrial Cancer Risk in a Chinese Population

    PubMed Central

    Dorjgochoo, Tsogzolmaa; Xiang, Yong-Bing; Long, Jirong; Shi, Jiajun; Deming, Sandra; Xu, Wang-Hong; Cai, Hui; Cheng, Jiarong; Cai, Qiuyin; Zheng, Wei; Shu, Xiao-Ou

    2013-01-01

    Background In vitro studies have demonstrated the role of the BCL-2 family of genes in endometrial carcinogenesis. The role of genetic variants in BCL-2 genes and their interactions with non-genetic factors in the development of endometrial cancer has not been investigated in epidemiological studies. Patients and Methods We examined the relationship between BCL-2 gene family variants and endometrial cancer risk among 1,028 patients and 1,922 age-matched community controls from Shanghai, China. We also investigated possible interactions between genetic variants and established risk factors (demographic, lifestyle and clinical). Individuals were genotyped for 86 tagging single nucleotide polymorphisms (SNPs) in the BCL2, BAX, BAD and BAK1 genes. Results Significant associations with endometrial cancer risk were found for 9 SNPs in the BCL2 gene (P trend<0.05 for all). For SNPs rs17759659 and rs7243091 (minor allele for both: G), the associations were independent. The odds ratio was 1.27 (95% CI: 1.04–1.53) for women with AG genotype for the SNP rs17759659 and 1.82 (95% CI: 1.21–2.73) for women with the GG genotype for the SNP rs7243091. No interaction between these two SNPs and established non-genetic risk factors of endometrial cancer was noticed. Conclusion Genetic polymorphisms in the BCL2 gene may be associated with the risk of endometrial cancer in Chinese women. PMID:23637776

  18. Ru(II)/diphenylphosphine/pyridine-6-thiolate complexes induce S-180 cell apoptosis through intrinsic mitochondrial pathway involving inhibition of Bcl-2 and p53/Bax activation.

    PubMed

    Pires, Wanessa Carvalho; Lima, Benedicto Augusto Vieira; de Castro Pereira, Flávia; Lima, Aliny Pereira; Mello-Andrade, Francyelli; Silva, Hugo Delleon; da Silva, Monize Martins; Colina-Vegas, Legna; Ellena, Javier; Batista, Alzir A; de Paul Silveira-Lacerda, Elisângela

    2017-08-09

    The aim of this work was the synthesis, characterization, and cytotoxicity evaluation of three new Ru(II) complexes with a general formula [Ru(Spy)(bipy)(P-P)]PF6 [Spy = pyridine-6-thiolate; bipy = 2,2'-bipyridine; P-P = 1,2-bis(diphenylphosphine)ethane (1); 1,3-bis(diphenylphosphine) propane (2); and 1,1'-bis(diphenylphosphino)ferrocene] (4). Complex (3) with the 1,4-bis(diphenylphosphine)butane ligand, already known from the literature, was also synthesized, to be better studied here. The cytotoxicities of the complexes toward two kinds of cancerous cells (K562 and S-180 cells) were evaluated and compared to normal cells (L-929 and PBMC) by MTT assay. The complex [Ru(Spy)(bipy)(dppb)]PF6 (3) was selected to study both the cellular and molecular mechanisms underlying its promising anticancer action in S-180 cells. The results obtained from this study indicated that complex (3) induces cell cycle arrest in the G0/G1 phase in S-180 cells associated with a decrease in the number of cells in S phase. After 24 and 48 h of exposure to complex (3), the cell viability decreased when compared to the negative control. Complex (3) does not appear to be involved in the DNA damage, but induced changes in the mitochondrial membrane potential in S-180 cells. Furthermore, there was also an increase in the gene expression of Bax, Caspase 9, and Tp53. According to our results, complex (3) induces cell apoptosis through p53/Bax-dependent intrinsic pathway and suppresses the expression of active antiapoptotic Bcl-2 protein.

  19. Celecoxib aggravates cardiac apoptosis in L-NAME-induced pressure overload model in rats: Immunohistochemical determination of cardiac caspase-3, Mcl-1, Bax and Bcl-2.

    PubMed

    Mosaad, Sarah M; Zaitone, Sawsan A; Ibrahim, Abdelazim; El-Baz, Amani A; Abo-Elmatty, Dina M; Moustafa, Yasser M

    2017-06-25

    The mechanism of celecoxib cardiovascular adverse events was earlier investigated; yet in-depth investigations are needed to assess the involvement of its pro-apoptotic effect throughout this process. An in-vivo chronic rat model of pressure overload employing Nʷ-nitro-l-arginine methyl ester (L-NAME) was tested at different time intervals to ensure the occurrence of persistent myocardial apoptosis along with pressure overload. Seven groups of male Wistar rats were assigned as (i) distilled water; (ii-iv) L-NAME (60 mg/kg) for 6, 12 or 16 weeks; (v-vii) L-NAME [16 weeks] + celecoxib (25, 50 or 100 mg/kg), from week 13 to week 16. Treatment with L-NAME for 6, 12 or 16 weeks increased systolic blood pressure, serum level of creatine kinase-MB and lactate dehydrogenase. Further, it induced cardiac hypertrophy, detected in terms of greater heart weight index and cardiomyocyte cross-sectional area and produced interstitial and perivascular fibrosis. Moreover, administration of L-NAME increased cardiac immunostaining for activated caspase-3 and Bax/Bcl-2 ratio whereas; immunostaining for Mcl-1 was decreased. Administration of celecoxib (25, 50 or 100 mg/kg) aggravated the L-NAME-induced toxicity. The work results shed the light on the putative pro-apoptotic effect of celecoxib at a risk state of pressure overload comparable to the clinical condition of essential hypertension. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. 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

  1. [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.

  2. miR-125b-5p enhances chemotherapy sensitivity to cisplatin by down-regulating Bcl2 in gallbladder cancer

    PubMed Central

    Yang, Dong; Zhan, Ming; Chen, Tao; Chen, Wei; Zhang, Yunhe; Xu, Sunwang; Yan, Jinchun; Huang, Qihong; Wang, Jian

    2017-01-01

    Gallbladder cancer represents the most common malignancy of the biliary tract and is highly lethal with less than 5% overall 5-year survival rate. Chemotherapy remains the major treatment for late-stage patients. However, insensitivity to these chemotherapeutic agents including cisplatin is common. MicroRNAs (miRNAs) have been shown as modulators of drug resistance in many cancer types. We used genome-wide gene expression analysis in clinical samples to identify miR-125b-5p down-regulated in gallbladder cancer. miR-125b-5p up-regulation promoted cell death in gallbladder cancer cells in the presence of cisplatin. In contrast, knockdown of miR-125b-5p reduced cell death in gallbladder cancer cells treated with cisplatin. Up-regulation of miR-125b-5p significantly decreased tumor growth in combination with cisplatin in a mouse model. We identified Bcl2 as a direct target of miR-125b-5p which mediates the function of miR-125b-5p in gallbladder cancer. In clinical samples, miR-125b-5p was down-regulated in gallbladder cancer whereas Bcl2 was up-regulated and their expression was inversely correlated. Moreover, low miR-125b-5p expression or high expression of Bcl2 is correlated with poor prognosis in gallbladder cancer. Taken together, our findings indicate that miR-125b-5p is a potent chemotherapy sensitizer and may function as a new biomarker for the prognosis of gallbladder cancer patients. PMID:28256505

  3. Light induced apoptosis is accelerated in transgenic retina overexpressing human EAT/mcl-1, an anti-apoptotic bcl-2 related gene

    PubMed Central

    Shinoda, K.; Nakamura, Y.; Matsushita, K.; Shimoda, K.; Okita, H.; Fukuma, M.; Yamada, T.; Ohde, H.; Oguchi, Y.; Hata, J.; Umezawa, A.

    2001-01-01

    BACKGROUND/AIM—EAT/mcl-1 (EAT), an immediate early gene, functions in a similar way to bcl-2 in neutralising Bax mediated cytotoxicity, suggesting that EAT is a blocker of cell death. The aim of this study was to determine the effect of overexpression of the human EAT gene on light induced retinal cell apoptosis.
METHODS—EAT transgenic mice incorporating the EF-1α promoter were utilised, and expression of human EAT was detected by RT-PCR. Light damage was induced by raising mice under constant illumination. Two groups of animals, EAT transgenic mice (n=14) and littermates (n=13), were examined by ERG testing and histopathology at regular time points up to 20 weeks of constant light stimulation. Electrophysiological and histopathological findings were evaluated by established systems of arbitrary scoring as scores 0-2 and scores 0-3, respectively.
RESULTS—The mean score (SD) of ERG response was significantly lower in EAT transgenic mice (0.79 (0.89)) than in littermates (1.69 (0.48)) (p<0.01). Although the differences between the two survival curves did not reach statistical significance (p=0.1156), the estimated incidence of electrophysiological retinal damage was higher in EAT mice (0.0495/mouse/week; 95% confidence interval (CI) 0.0347-0.0500) than in littermates (0. 0199/mouse/week; 95% CI 0.0035-0.0364). The mean scores (SD) for histopathological retinal degeneration were 2.31 (0.63) in littermates and 1.43 (1.22) in EAT transgenic mice (p=0.065). However, Kaplan-Meier curves for histopathological failure in two groups of mice showed that retinal photoreceptor cells were preserved significantly against constant light in the littermate compared with transgenic mice (p=0.0241). The estimated incidence of histopathological retinal damage was 0.0042/mouse/week in the littermates (95% CI 0-0.0120) and 0.0419/mouse/week in the EAT mice (95% CI 0.0286-0.0500).
CONCLUSION—Retinal photoreceptor cell apoptosis under constant light stimulation is

  4. A preliminary study of apoptosis induction in glioma cells via alteration of the Bax/Bcl-2-p53 axis by transformed and non-transformed root extracts of Leonurus sibiricus L.

    PubMed

    Sitarek, Przemysław; Skała, Ewa; Toma, Monika; Wielanek, Marzena; Szemraj, Janusz; Nieborowska-Skorska, Malgorzata; Kolasa, Maciej; Skorski, Tomasz; Wysokińska, Halina; Śliwiński, Tomasz

    2016-07-01

    Leonurus sibiricus L. is a traditional medicinal plant which occurs in southern Siberia, China, Korea, Japan, and Vietnam. The plant shows several pharmacological effects, but the most interesting is its anti-cancer activity. The aim of our study was to examine the induction of apoptosis in malignant glioma cells, the most aggressive primary brain tumors of the central nervous system, following treatment with transformed root (TR) or non-transformed root (NR) L. sibiricus extracts. Both the NR and TR extracts were found to have cytotoxic activity in the glioma primary cells. The human glioblastoma cell lines obtained from patients were confirmed to be tumorogenic by the following three markers: D10S1709, D10S1172, and D22S283. HPLC and MS analysis revealed the presence of polyphenolic compounds (chlorogenic acid, ferulic acid, caffeic acid, p-coumaric acid, ellagic acid, and verbascoside) in both sets of root extracts. In summary, our findings demonstrate that treatment of the glioma cells with NR and TR extracts resulted (a) in significant cell growth inhibition, (b) S- and G2/M-phase cell cycle arrest, and (c) apoptosis in a dose-dependent fashion by changing Bax/Bcl-2 ratio (about 4-fold increase) and p53 (5-fold increase) activation. These findings indicate that NR and TR extracts exhibit anti-cancer activity through the regulation of genes involved in apoptosis. This is the first report to demonstrate the cytotoxic effect of polyphenolic extracts from L. sibiricus roots against glioma cells, but further studies are required to understand the complete mechanism of its apoptosic activity.

  5. 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

  6. Ghrelin Administration Increases the Bax/Bcl-2 Gene Expression Ratio in the Heart of Chronic Hypoxic Rats.

    PubMed

    Aliparasti, Mohammad Reza; Alipour, Mohammad Reza; Almasi, Shohreh; Feizi, Hadi

    2015-06-01

    Programmed cell death or apoptosis, is a biochemical procedure that initiates due to some conditions, including hypoxia. Bax and Bcl-2 are among the agents that regulate apoptosis. The amplification of the first one triggers the initiation of apoptosis, and the second one prevents it. Ghrelin is an endogenous peptide that antiapoptosis is its new effect. The aim of this study is to examine the effect of ghrelin on the Bax/Bcl-2 ratio. Twenty four wistar rats were divided randomly in three groups; control, hypoxic + saline and hypoxic + ghrelin. Hypoxic animals lived in O2 11% for 2 weeks and received either saline or ghrelin subcutaneously daily. The bax and Bcl-2 gene expression were measured by Real-Time RT-PCR. Chronic hypoxia increased the Bax gene expression significantly compared with normal animals (P = 0.008), but the Bcl-2 was not affected by hypoxia. The Bax/Bcl-2 ratio also amplified significantly (P=0.005). Ghrelin administration significantly increased the Bax/Bcl-2 ratio in the hypoxic animals compared to the hypoxic + saline and normal groups (p=0.042 and P= 0.001, respectively). In the present study, animals' treatment with ghrelin leads to an increment of Bax/Bcl-2 ratio, which indicates a controversy related to cardioprotection of ghrelin.

  7. Ghrelin Administration Increases the Bax/Bcl-2 Gene Expression Ratio in the Heart of Chronic Hypoxic Rats

    PubMed Central

    Aliparasti, Mohammad Reza; Alipour, Mohammad Reza; Almasi, Shohreh; Feizi, Hadi

    2015-01-01

    Purpose: Programmed cell death or apoptosis, is a biochemical procedure that initiates due to some conditions, including hypoxia. Bax and Bcl-2 are among the agents that regulate apoptosis. The amplification of the first one triggers the initiation of apoptosis, and the second one prevents it. Ghrelin is an endogenous peptide that antiapoptosis is its new effect. The aim of this study is to examine the effect of ghrelin on the Bax/Bcl-2 ratio. Methods: Twenty four wistar rats were divided randomly in three groups; control, hypoxic + saline and hypoxic + ghrelin. Hypoxic animals lived in O2 11% for 2 weeks and received either saline or ghrelin subcutaneously daily. The bax and Bcl-2 gene expression were measured by Real-Time RT-PCR. Results: Chronic hypoxia increased the Bax gene expression significantly compared with normal animals (P = 0.008), but the Bcl-2 was not affected by hypoxia. The Bax/Bcl-2 ratio also amplified significantly (P=0.005). Ghrelin administration significantly increased the Bax/Bcl-2 ratio in the hypoxic animals compared to the hypoxic + saline and normal groups (p=0.042 and P= 0.001, respectively). Conclusion: In the present study, animals’ treatment with ghrelin leads to an increment of Bax/Bcl-2 ratio, which indicates a controversy related to cardioprotection of ghrelin. PMID:26236657

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