Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P10415 (Bcl-2)
 33,771 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Expression of the apoptosis-associated proteins Bcl-2 and Bax was quantitated by flow cytometry (FCM) in chemosensitive testicular germ-cell tumor NT2 cells, and the results were compared with those obtained by Western blotting. NT2 cells were incubated with cisplatin (3.1 microM for 2 h at 37 degrees C), and 24, 48, and 72 h later were analyzed for induction of apoptosis, and for modulation of the expression of cell death suppressing protein Bcl-2, as well as cell death promoting protein Bax. Apoptosis was quantitated by binding of annexin V conjugated with fluorescein isothiocyanate (FITC) to the cell membrane. Cisplatin-treatment induced apoptosis in NT2 cells. The apoptotic cell population increased in time, and at t = 72 h after drug incubation, about 90% of cells that were present in the cell culture were apoptotic. Subsequently, we determined the expression of the Bcl-2 and Bax proteins by FCM and Western blotting before and after drug treatment. NT2 cells had low constitutive expression levels of Bcl-2 and elevated constitutive expression levels of Bax protein, as determined by both methods. At t = 24 h and 48 h after drug treatment, no changes were observed in the expression of the Bcl-2 protein, as quantitated by FCM and Western blotting. Also, the expression of the Bax protein had not changed, based on Western blotting. However, FCM revealed that in a specific subpopulation of drug-treated NT2 cells, Bax expression was increased. On the basis of forward and perpendicular light-scatter this subpopulation, which consisted of large, early apoptotic, swollen cells with increased internal complexity, was sorted, and showed abundant Bax protein by FCM and Western blotting. Our results demonstrate that the chemosensitivity of NT2 cells is probably due to a low intrinsic threshold for drug-induced apoptosis that is accompanied by overexpression of the death-promoting Bax protein during the early stages of the apoptotic process. We conclude that FCM is superior to Western blotting for the detection of heterogeneous expression of Bax in a given cell population.
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PMID:Bax upregulation is an early event in cisplatin-induced apoptosis in human testicular germ-cell tumor cell line NT2, as quantitated by flow cytometry. 904 Nov 17

Cisplatin exposure induces apoptosis in HeLa cells. Since the interaction of this drug with DNA produces reactive oxygen species, we performed an analysis of the oxidative stress-responsive factors AP-1 and NF-kappa B. Although AP-1 levels were not modified during cisplatin exposure, electrophoretic mobility shift assays demonstrated an increase in NF-kappa B DNA binding activity that correlated with a decrease of the inhibitory protein I kappa B alpha and a specific relocalization of c-Rel, as assessed by immunoblotting and immunofluorescence. No changes in the levels or localization of p65 were found. Interestingly, I kappa B alpha relocalized to the nucleus, probably in order to regulate the binding of specific complexes. This process was accompanied by a decrease of the antiapoptotic protein Bcl-2, and a relocalization of p53 protein to the nucleus. Since HeLa cells lost most of their p53 protein due to a specific E6-dependent degradation, cisplatin could be inhibiting this degradation, since the p53 total levels were not increased during the exposure to the drug.
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PMID:Modulation of NF-kappa B, and Bcl-2 in apoptosis induced by cisplatin in HeLa cells. 940 32

Cisplatin and VP-16 were used to study the induction of apoptosis in Panc-1 cells. Cisplatin and VP-16 inhibited the growth of Panc-1 cells. After 2 hours exposure to cisplatin or VP-16, attached and detached cells were subjected to TUNEL staining to calculate the ratio of apoptosis. In detached cells TUNEL positive ratios increased in a time- and dose-dependent manner. In Western blotting, Bax expression was obviously up-regulated, but Bcl-2 remained almost constant. The results suggested that in Panc-1 cells cisplatin and VP-16 induced apoptotic cell death which was mediated through the interaction of Bax expression in the presence of mutated p53.
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PMID:Mechanism of apoptosis induced by cisplatin and VP-16 in PANC-1 cells. 941 85

This study was designed to assess the efficacy of a new antimelanoma therapeutic strategy that relies on the use of a c-myc antisense 15-mer phosphorothioate oligodeoxynucleotide ([S]ODN), in combination with cisplatin (cis-diamminedichloroplatinum; DDP), which is currently used in the clinical management of melanoma patients. Proliferation and colony formation of melanoma cells were both inhibited by the DDP/c-myc antisense [S]ODN combination to a greater extent than that observed with either agent alone. Inhibition was most effective when DDP was followed by c-myc antisense [S]ODNs. Cell cycle flow cytometric analysis of cells exposed to the two agents either alone or in combination demonstrated that (a) c-myc antisense [S]ODNs induced an accumulation of cells in S phase and apoptosis in a fraction of the cells, detectable at day 5 after the beginning of treatment; (b) DDP induced a block in G2-M phase detectable at day 1, which was partially recovered, and apoptosis similar in extent to that induced by c-myc antisense [S]ODNs; and (c) DDP and c-myc antisense [S]ODNs together induced arrest in G2-M phase, which was maximum at day 3, i.e., delayed as compared to the block induced by DDP. The combination induced a higher percentage of apoptosis, evident at day 3 from the start of treatment, that correlated with a marked reduction in Bcl-2 expression. Mice bearing human melanoma xenografts and treated sequentially with DDP and c-myc antisense [S]ODNs showed a higher inhibition of tumor growth, reduction in the number of lung metastases, and increase in life span compared with those treated with either agent alone. Together, these data lend support to the development of anticancer therapies involving oncogene-targeted antisense ODNs and conventional antineoplastic drugs.
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PMID:c-myc antisense oligodeoxynucleotides enhance the efficacy of cisplatin in melanoma chemotherapy in vitro and in nude mice. 944 6

We investigated the roles of p53 and Bcl-2 homologues in the induction of apoptosis by cisplatin and paclitaxel in wild-type p53-expressing human ovarian carcinoma cells and cisplatin-resistant derivatives that have lost p53 function. Cisplatin induced apoptosis in parental A2780 but not in cisplatin-resistant A2780/cp70 cells, whereas paclitaxel induced apoptosis in both cell lines. Immunoprecipitation of p53 using antibodies specific for p53 conformation (pAb 1620 and pAb 240) showed that there were no relative changes in p53 conformation before and after cisplatin treatment in either cell line. A2780/cp70 cells have lost p53 function, yet they have wild-type p53 gene sequence. However, A2780/cp70 cells constitutively express more p53 in a form detected by pAb 240, an antibody that also detects mutant conformations of p53 that are transcriptionally inactive. There were no changes in levels of Bcl-2, Bcl-XL, or 24-kDa Bax over 72 hr after exposure to cisplatin or paclitaxel, but each agent led to up-regulation of Bak and 21-kDa Bax in A2780 cells. Paclitaxel, but not cisplatin, increased Bak and 21-kDa Bax levels in A2780/cp70 cells. These data suggest that apoptosis in A2780 and A2780/cp70 is associated with an increased level of Bak and 21 kDa Bax after drug-induced damage and that functional p53 may be required for this effect after cisplatin but not after paclitaxel.
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PMID:Cisplatin- and paclitaxel-induced apoptosis of ovarian carcinoma cells and the relationship between bax and bak up-regulation and the functional status of p53. 958 7

Cisplatin exerts its cytotoxicity by inducing apoptosis. Similarly, all-trans retinoic acid (ATRA) causes apoptosis in certain cells. We studied the interaction of cisplatin and ATRA in human ovarian adenocarcinoma cells 2008, in human head and neck squamous carcinoma cells UMSCC10b, and in their respective cisplatin-resistant sub-lines. ATRA enhanced the cytotoxicity of cisplatin. The interaction of the drugs was synergistic in combination index-isobologram analyses (combination index >0.5 at 50% cell survival) in all of the cell lines tested. ATRA inhibited the cellular accumulation of the cisplatin analogue [3H] cis-dichloroethylenediamineplatinum(II) by 22-33% in three of four cell lines tested but did not alter the cellular content of reduced glutathione. The expression of Bcl-2 relative to Bax decreased more after combined treatment with cisplatin and ATRA than after either drug alone. The apoptotic mechanism of cell death was confirmed by demonstrating cleavage of poly(ADP-ribose)polymerase and by morphological analysis. The combined treatment with ATRA and cisplatin induced apoptosis in significantly more cells than either drug alone. We conclude that ATRA enhances the cytotoxicity of cisplatin by facilitating apoptosis in ovarian and head and neck carcinoma cells.
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PMID:all-trans retinoic acid enhances cisplatin-induced apoptosis in human ovarian adenocarcinoma and in squamous head and neck cancer cells. 981 94

Expression of Bcl-2, Bax, p53 and induction of apoptosis were studied in cisplatin or Taxol treated monolayer and spheroid cultures of ovarian cancer cell lines (SKOV-3, UL-1, UL-3C). While cisplatin (15-75 microg/ml) induced apoptosis in monolayer and spheroid cultures, Taxol (100-800 nM) induced fragmentation in monolayers only. Cisplatin induced up to 5-fold DNA fragmentation in monolayers, while 3-fold (UL-3C, SKOV-3), and 1.5-fold (UL-1) in spheroids. Taxol treatment of monolayers resulted in the characteristic phosphorylation of Bcl-2, which was not demonstrated in spheroid cultures. Bax expression was reduced in spheroids following cisplatin or Taxol treatment, while p53 levels remained unchanged.
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PMID:Taxol-induced bcl-2 phosphorylation in ovarian cancer cell monolayer and spheroids. 1002 85

Combination chemotherapy using paclitaxel with a platinum-based regimen is currently the standard first-line therapy for ovarian cancer after surgical cytoreduction. Whereas cisplatin-paclitaxel combination chemotherapy has shown significant efficacy over previous drug combinations in ovarian cancer, 20-30% of patients fail to respond to this combination. These patients are deemed cisplatin-paclitaxel resistant, although it is unclear whether the tumors are resistant to one or both drugs. Because the options available to ovarian cancer patients for second-line therapy are limited, and knowing that mechanistic differences exist between cisplatin and paclitaxel, we assessed the efficacy of combination drug therapy on cisplatin-resistant (cisplatinR) ovarian cancer cells. We found that paclitaxel induced apoptosis in cisplatinR cells as well as in the cisplatin-sensitive parental cell lines. In cisplatinR C-13 cells, the concomitant addition of cisplatin blocked paclitaxel-induced apoptosis as determined by DNA fragmentation assays, fluorescence microscopy, and flow cytometry. Paclitaxel-induced multimininucleation was also inhibited when the cells were exposed sequentially to paclitaxel and then cisplatin. Cisplatin did not block paclitaxel-induced stabilization of microtubules or prevent paclitaxel-induced loss of Bcl-2 expression in cisplatinR cells. Conversely, paclitaxel did not inhibit p53 protein accumulation by cisplatin. These results suggest that cisplatin blocks paclitaxel-induced apoptosis at a point downstream of Bcl-2 degradation and independent of microtubule stabilization. Our research shows that cisplatin can inhibit the effectiveness of paclitaxel in cispatinR cell lines. Therefore, the establishment of a clinical protocol to evaluate the efficacy of paclitaxel alone versus another second-line regimen in patients with cisplatin-paclitaxel-resistant ovarian cancer is warranted.
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PMID:Cisplatin inhibits paclitaxel-induced apoptosis in cisplatin-resistant ovarian cancer cell lines: possible explanation for failure of combination therapy. 1034 53

Cisplatin (cis-diamminedichloroplatinum(II), CDDP) is one of the most important chemotherapeutic agents; however, the mechanisms of resistance to this drug are still unknown. Recent reports have demonstrated that chemotherapy can induce apoptosis in some cancer cells, indicating that apoptosis may play a very important role in cancer therapy. Therefore, we used a CDDP-resistant cell line from the human epidermoid carcinoma cell line A431 to investigate whether the modulation of apoptosis influences CDDP resistance. In the CDDP-resistant cell, the cell cycle was not perturbed after CDDP treatment. DNA gel electrophoresis and ELISA of the CDDP-resistant cell showed reduced apoptosis when compared with A431 cells treated with CDDP. We determined the p53, Bcl-2, Bax and CPP32 protein levels by Western blotting. This analysis demonstrated a marked increase in Bcl-2 protein levels and a reduction in CPP32 protein levels in CDDP-resistant cells. Our results indicate that the reduction of apoptosis was one of the CDDP-resistant mechanisms, and that reduced apoptosis in CDDP-resistant cells was influenced by Bcl-2 and CPP32 proteins.
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PMID:Regulation of apoptosis reduction in the cisplatin-resistant A431 cell line by Bcl-2 and CPP32. 1060

In this study, we describe the effects produced by the retroviral transduction of human type I consensus IFN (CIFN) coding sequence into the 8863 and 1B6 human melanoma cell lines, derived from a metastatic and a primary human melanoma, respectively. Melanoma cell lines producing approximately 103 IU/ml of IFN were obtained. Interestingly, cisplatin treatment of IFN-producing 8863 and 1B6 melanoma cells resulted in a three- to four-fold increase in the percentage of apoptotic cells with respect to similarly treated parental or control-transduced cell cultures. A similar effect, although less intense, was caused by cultivation of parental melanoma cells in the presence of exogenous CIFN. The increased susceptibility of the IFN-producing melanoma cell lines to cisplatin-induced apoptosis was associated with an IFN-dependent accumulation of p53, which also correlated with a decrease in Bcl-2 expression. Addition of exogenous CIFN to parental melanoma cells resulted in similar although weaker modulations of p53 and Bcl-2 expression. Cisplatin administration to nude mice bearing 3-day-old IFN-producing 8863 tumors resulted in complete tumor regression, while only a partial tumor inhibition was observed upon cisplatin treatment of mice bearing parental or control-transduced 8863 tumors. Starting the cisplatin treatment 7 days after tumor cell injection still resulted in a stronger inhibition of tumor growth in the mice bearing IFN-producing 8863 tumors as compared with parental tumor-bearing mice. A comparable therapeutic effect was obtained after repeated peritumoral administration of 103 IU of exogenous CIFN and cisplatin treatment. Interestingly, a spontaneous tumor regression was observed in nude mice injected with IFN-producing 1B6 cells, in contrast to the progressive tumor growth occurring in mice receiving a similar inoculum of the parental or control-transduced 1B6 melanoma cells. Repeated peritumoral administration of 103 IU of exogenous CIFN to mice bearing parental 1B6 tumors caused only a transient inhibition of tumor growth. These results indicate that type I IFN gene transfer is an effective approach for suppressing the tumorigenic phenotype of human melanoma cells and for increasing the efficacy of anticancer drugs. These observations, together with our previous findings showing the importance of IFN-alpha-T cell interactions in the generation of an antitumor response in mouse models, underline the interest of using type I IFN in gene therapy strategies for the treatment of human melanoma.
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PMID:Type I consensus interferon (CIFN) gene transfer into human melanoma cells up-regulates p53 and enhances cisplatin-induced apoptosis: implications for new therapeutic strategies with IFN-alpha. 1067 21


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