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

The observation that follicular dendritic cells (FDC) reduce apoptosis in B cells prompted the hypothesis that FDC might enhance tumor cell survival by protecting malignant B cells from apoptotic death. To test this notion, apoptosis was induced in B cell lymphomas by anti-Fas or various antineoplastic agents in the presence and absence of FDC. Apoptosis was detected and quantified by TUNEL analysis. Induction of apoptosis with anti-Fas, etoposide, cyclophosphamide, and busulfan was markedly antagonized by FDC at FDC to B cell ratios of >/=1:16. For example, treatment with 10 ng/ml anti-Fas caused 60-90% of A20 cells to undergo apoptosis in 6 h, whereas addition of FDC reduced apoptosis to background levels (3-15%). Similarly, treatment with busulfan induced apoptosis in 55-80% of A20 cells, whereas addition of FDC reduced B cell death to </=15%; moreover, depletion of FDC abrogated the protective actions. In contrast, the apoptosis-inducing effect of Adriamycin was not reversed by FDC. The ability to block apoptosis induced by anti-Fas or busulfan was not limited to A20 but was observed in four other malignant pre-B cell or B cell lines. The mechanism by which FDC spare malignant B cells from apoptosis did not involve alterations in levels of Bcl-2, Bcl-XL, or Bax. Collectively, these data raise the possibility that FDC may enhance tumor cell survival by protecting malignant B cells against apoptosis induced by anti-Fas and some but not all chemotherapeutic agents.
 ...
PMID:Follicular dendritic cells protect malignant B cells from apoptosis induced by anti-Fas and antineoplastic agents. 1058 34

The second most prevalent urological malignancy in middle aged and elderly men is bladder cancer, with 90% of the cases being transitional cell carcinomas. The success of current systemic and intravesical therapeutic agents, such as cisplatin, thiotepa, Adriamycin, mitomycin C, and bacillus Calmette-Guerin, is limited with recurrence rates reduced to 17-44%. In addition, most of these agents require instrumentation of the urinary tract and are delivered at a significant cost and potential morbidity to the patient. Fluroquinolone antibiotics such as ciprofloxacin, which can be administered p.o., may have a profound effect in bladder cancer management. This is primarily based on limited in vitro studies on tumor cells derived from transitional cell carcinoma of the bladder that revealed a dose- and time-dependent inhibition of cell growth by ciprofloxacin at concentrations that are easily attainable in the urine of patients. However, the mechanism(s) by which ciprofloxacin elicits its biological effects on bladder cancer cells is not well documented. Our experimental data confirm previous studies showing the in vitro cell growth inhibition of the transitional cell carcinoma of the bladder cell line HTB9 and further showed the induction of cell cycle arrest at the S/G2-M checkpoints. In addition, we found down-regulation of cyclin B, cyclin E, and dephosphorylation of cdk2 in ciprofloxacin-treated bladder tumor cells. There was also an up-regulation of Bax, which altered the Bax:Bcl-2 ratio, which may be responsible for mitochondrial depolarization reported to be involved prior to the induction of apoptosis. The cyclin-dependent kinase inhibitor p21WAF1 level was found to be decreased within 12 h of ciprofloxacin treatment and disappeared completely when HTB9 cells were treated with 200 microg/ml ciprofloxacin for 24 h. The down-regulation of p21WAF1 closely correlated with poly(ADP-ribose) polymerase cleavage and CPP32 activation. Recent studies revealed that p21WAF1 protects cells from apoptosis by arresting them in G1 and further binds to pro-caspase-3, preventing its activation and thus, inhibiting the apoptotic cascade. Hence, the down-regulation of p21WAF1, together with the alterations in Bax and cdk2 as observed in our studies, may define a novel mechanism by which ciprofloxacin inhibits tumor cell growth and induces apoptotic cell death. The results of our current studies provide strong experimental evidence for the use of ciprofloxacin as a potential preventive and/or therapeutic agent for the management of transitional cell carcinoma of the bladder.
 ...
PMID:Ciprofloxacin mediated cell growth inhibition, S/G2-M cell cycle arrest, and apoptosis in a human transitional cell carcinoma of the bladder cell line. 1074 13

We investigated the capacity of 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] and all-trans-retinoic acid (ATRA) to sensitize three breast cancer cell lines to the cell killing effects of paclitaxel (Taxol) and Adriamycin, two chemotherapeutic agents commonly used in the treatment of breast cancer. In tissue culture colony assays, 1,25(OH)2D3 and ATRA were synergistic in inhibiting the clonogenicity of MCF-7 and T-47D cells that expressed estrogen receptor; vitamin D receptor; retinoic acid receptors (RARs) alpha, beta, and gamma; and retinoid X receptors alpha, beta, and gamma but were not additive in MDA-MB-231 cells that lacked expression of estrogen receptor, RARalpha, and RARbeta. The hormones used individually or in combination induced up to 40-50% cell death by a trypan blue exclusion assay in a dose-dependent manner up to concentrations of 10(-7) M in MCF-7 and T-47D cells, more modestly in MDA-MB-231 cells, and not at all in MCF-10 and MCF-12 nontransformed mammary epithelial cells. Pretreating the cancer cell lines with 1,25(OH)2D3 and ATRA individually or in combination for 3 days prior to a 1-h incubation with paclitaxel or Adriamycin decreased the ED50 for inhibition of colony formation or for cell death by trypan blue by up to 2 logs for paclitaxel and up to 1 log for Adriamycin in all three cell lines but had no effect on chemotherapy-induced MCF-12 cell death. The effects of the hormones were synergistic with those of the chemotherapy agents in all of the breast cancer cell lines, generally at the higher concentrations. Cell death took place by apoptosis. To determine one potential reason for the greater potentiation of the effects of paclitaxel than those of Adriamycin, we determined the effects of preincubation of MCF-7 cells on paclitaxel-induced phosphorylation of Bcl-2. Pretreatment of MCF-7 cells with either 1,25(OH)2D3 or ATRA increased the phosphorylation of Bcl-2 by variable concentrations of paclitaxel. These data suggest that pretreatment of breast cancer with 1,25(OH)2D3 or ATRA lowers the threshold for cell killing by chemotherapy agents and may provide a novel treatment option for this disease.
 ...
PMID:1,25-Dihydroxyvitamin D3 and all-trans-retinoic acid sensitize breast cancer cells to chemotherapy-induced cell death. 1076 96

We have previously shown that Bcl-2 expression was negative prognostic factor in transitional cell cancer (TCC), and that TCC cell lines expressing high levels of Bcl-2 are resistant to Adriamycin triggered apoptosis. Here we examined antisense oligonucleotide-mediated downregulation of Bcl-2 expression and its effect on sensitivity to Adriamycin (ADM) treatment in T24 cells. Treatment of T24 cells with 20 microM of bcl-2 antisense phosphorothioate oligodeoxynucleotide (PODN) reduced the Bcl-2 protein level. Combined administration with Adriamycin resulted in synergistic cytotoxicity, accompanied with a 2.4-fold increase in DEVD-specific caspase activity. The finding provides evidence that Bcl-2 expression may be critical for maintaining the drug resistance of TCC. bcl-2 antisense PODN might be useful means for overcoming drug resistance in highly malignant TCC.
 ...
PMID:Caspase involved synergistic cytotoxicity of bcl-2 antisense oligonucleotides and adriamycin on transitional cell cancer cells. 1082 35

Anti-Fas monoclonal antibody (mAb) kills Fas-expressing cells by apoptosis. Several anticancer agents also mediate apoptosis and may share common intracellular pathways leading to apoptosis with Fas. Thus, we reasoned that combination treatment of drug-resistant cells with anti-Fas mAb and drugs might overcome their resistance. We investigated whether anticancer agents enhance Fas-mediated apoptosis and cytotoxicity against renal cell carcinoma (RCC) cells. Treatment of ACHN RCC cells with anti-Fas mAb in combination with 5-fluorouracil, vinblastine, IFN-alpha, or IFN-gamma did not overcome resistance to these agents. However, combination treatment with anti-Fas mAb and Adriamycin (ADR) resulted in a synergistic cytotoxic effect. Furthermore, synergy was also obtained even when the exposure time was shortened from 24 h to 8 or 2 h. Synergy was also achieved in four other RCC cell lines and five freshly derived human RCC cells. Treatment with anti-Fas mAb in combination with epirubicin or pirarubicin also resulted in a synergistic cytotoxic effect on ACHN cells. Similar results were achieved with a combination of humanized anti-Fas mAb and ADR. Incubation of ACHN cells with ADR augmented the expression of Fas and p53, but not Bcl-2, Bax, or caspase-3. However, the activity of caspase-3 itself was apparently enhanced after treatment with ADR alone or combined treatment with anti-Fas mAb. The synergy obtained in cytotoxicity with anti-Fas mAb and ADR was also achieved in apoptosis. Exposure of ACHN cells and freshly derived RCC cells to ADR enhanced their susceptibility to lysis by peripheral blood lymphocytes and tumor-infiltrating lymphocytes. This study demonstrates that combination treatment of RCC cells with anti-Fas mAb and ADR might overcome their resistance. The sensitization required a low concentration of ADR and a short exposure time, thus supporting the potential in vivo application of a combination of ADR and anti-Fas mAb or immunotherapy in the treatment of ADR- and/or immunotherapy-resistant RCC.
 ...
PMID:Enhancement of Fas-mediated apoptosis in renal cell carcinoma cells by adriamycin. 1085 Apr 37

There is growing evidence which suggests that dysregulation of apoptosis may lead to several disease states including cancer. To investigate the mechanism controlling the induction of cell death, apoptosis defective/resistant (Apt-) mutants were isolated and characterized in this study. FDC-P1, a mouse myeloid cell line that depends upon IL-3 for survival and growth but undergoes apoptosis when deprived of growth factor, was mutagenized by treatment with ethyl methane sulfonate. We selected cells that survived the growth factor deprivation but did not grow without the factor. Surviving cells were cloned by limiting dilution and four clones that showed the least morphological characteristics and biochemical changes of apoptosis were chosen. Unlike the parent FDC-P1, these mutants were cross resistant to apoptosis induced by a variety of antitumor drugs such as Adriamycin, Dexamethasone, VP-16, as well as reactive oxygen species (ROS) generated by xanthine/xanthine oxidase (X/XO). We used one of these Apt- mutant to test candidate death genes. Our findings suggest that the preferential increase in Bax/Bcl-2 ratio, p53, c-Myc, Caspase-3 and decrease in AP-1 on treatment with various anticancer drugs may contribute to the preferential apoptotic response in FDC-P1 cells but to varying degrees. Whereas, the higher constitutive level of antioxidant enzymes superoxide dismutase and catalase in the Apt- mutant may contribute at least in part to its resistance.
 ...
PMID:Differential sensitivity of murine myeloid FDC-P1 cells and apoptosis resistant mutant(s) to anticancer drugs. 1123 67

The dose-dependent cardiomyopathy and heart failure due to adriamycin have been shown to be due to increased oxidative stress and loss of myocytes. We examined the incidence of myocardial apoptosis as well as changes in the expression of apoptotic regulatory gene products in an established animal model of adriamycin cardiomyopathy. Rats were treated with adriamycin (cumulative dose, 15 mg/kg), and the hearts were examined for apoptosis as well as expression of Bax, caspase 3, and Bcl-2 at 0, 4, 10, 16, and 21 days after the treatment. A significant increase in the incidence of apoptosis was seen at 4 days, followed by a decline at 10 and 16 days of posttreatment. At 21 days, the number of apoptotic cells increased again and included cells of the conducting system. Expression of Bax corresponded to these biphasic changes, whereas the converse was true for the expression of Bcl-2. The latter peaked at 10 days followed by a decline at 16 and 21 days. The Bax/Bcl-2 ratio also correlated with the incidence of apoptosis. Expression of caspase 3 correlated with increased apoptosis, but only at early time points. Probucol (cumulative dose, 120 mg/kg), a known antioxidant as well as promoter of endogenous antioxidants, significantly reduced the incidence of apoptosis as well as expression of Bax. Adriamycin-induced hemodynamic changes were also prevented by probucol. These data suggest that adriamycin-induced apoptosis is mediated by oxidative stress and may play a role in the development of heart failure.
 ...
PMID:Apoptosis in adriamycin cardiomyopathy and its modulation by probucol. 1129 92

Treatment of patients with non-Hodgkin's lymphoma (NHL) is frequently hampered by development of chemoresistance. Rituximab is a chimeric mouse antihuman CD20 antibody that offers an alternative; however, its mechanism of action is not clearly understood. Treatment of lymphoma cell lines with Rituximab sensitizes the cells to the cytotoxic and apoptotic effects of therapeutic drugs, e.g., cisplatin, fludarabine, vinblastine, and Adriamycin. This study investigated the mechanism(s) involved in the reversal of drug resistance by Rituximab therapy. NHL cells synthesize and secrete antiapoptotic cytokines implicated in drug resistance, including interleukin (IL)-6, IL-10, and tumor necrosis factor alpha. We hypothesized, therefore, that sensitization by Rituximab may be due in part to modification of cytokine production. In this study, examination of cytokine secretion by NHL 2F7 tumor cells revealed down-regulation of IL-10 by Rituximab treatment. Moreover, cytotoxicity assays using exogenous IL-10 and IL-10-neutralizing antibodies demonstrated that IL-10 serves as an antiapoptotic/protective factor in these tumor cells against cytotoxic drugs. Furthermore, expression in 2F7 cells of the protective factor, Bcl-2, was shown to be dependent on IL-10 levels and down-regulated by Rituximab. Other gene products such as Bax, Bcl-x, Bad, p53, c-myc, and latent membrane protein-1 (LMP) were not affected by Rituximab treatment. Drug sensitization, as well as down-regulation of both IL-10 and Bcl-2, was corroborated in experiments using the NHL cell line 10C9. The Ramos and Daudi NHL cell lines were not sensitizable, nor did their Bcl-2 or IL-10 levels change. These studies demonstrate that one mechanism by which Rituximab sensitizes NHL to chemotherapeutic drugs is mediated through down-regulation of antiapoptotic IL-10 autocrine/paracrine loops and Bcl-2. The clinical relevance of these findings is discussed.
 ...
PMID:Inhibition of interleukin 10 by rituximab results in down-regulation of bcl-2 and sensitization of B-cell non-Hodgkin's lymphoma to apoptosis. 1129 68

The newly discovered member of the tumor necrosis factor superfamily, Apo2L/tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), has been identified as an apoptosis-inducing agent in sensitive tumor cells but not in the majority of normal cells, and hence it is of potential therapeutic application. However, many tumor cells are resistant to Apo2L/TRAIL-mediated apoptosis. Various chemotherapeutic drugs have been shown to sensitize tumor cells to members of the tumor necrosis factor family. However, it is not clear whether sensitization by drugs and sensitivity to drugs are related or distinct events. This study examined whether an Adriamycin-resistant multiple myeloma (MM) cell line (8226/Dox40) can be sensitized by Adriamycin (ADR) to Apo2L/TRAIL-mediated apoptosis. Treatment with the combination of Apo2L/TRAIL and subtoxic concentrations of ADR resulted in synergistic cytotoxicity and apoptosis for both the parental 8226/S and the 8226/Dox40 tumor cells. Adriamycin treatment modestly up-regulated Apo2L/TRAIL-R2 (DR5) and had no effect on the expression of Fas-associated death domain, c-FLIP, Bcl-2, Bcl(xL), Bax, and IAP family members (cIAP-1, cIAP-2, XIAP, and survivin). The protein levels of pro-caspase-8 and pro-caspase-3 were not affected by ADR, whereas pro-caspase-9 and Apaf-1 were up-regulated. Combination treatment with Apo2L/TRAIL and ADR resulted in significant mitochondrial membrane depolarization and activation of caspase-9 and caspase-3 and apoptosis. Because ADR is shown to sensitize ADR-resistant tumor cells to Apo2L/TRAIL, these findings reveal that ADR can still signal ADR-resistant tumor cells, resulting in the modification of the Apo2L/TRAIL-mediated signaling pathway and apoptosis. These in vitro findings suggest the potential application of combination therapy of Apo2L/TRAIL and subtoxic concentrations of sensitizing chemotherapeutic drugs in the clinical treatment of drug-resistant/Apo2L/TRAIL-resistant multiple myeloma.
 ...
PMID:Adriamycin sensitizes the adriamycin-resistant 8226/Dox40 human multiple myeloma cells to Apo2L/tumor necrosis factor-related apoptosis-inducing ligand-mediated (TRAIL) apoptosis. 1175 78

Adriamycin is a potent, broad-spectrum chemotherapeutic agent effective against solid tumors and malignant hematological disease. The major limiting factor for adriamycin is its cardiotoxicity. Thus, the objective of this study was to investigate the role of cardiomyocyte and endothelial cell apoptosis in adriamycin-induced cardiomyopathy, in vivo and in vitro. For in vivo study, intraperitoneal injections of adriamycin were administered to nine adult male Wistar rats and normal saline to six rats as control. Eight of the nine rats in the adriamycin group, but none in the control group, developed marked ascites and DNA ladders in agarose gel electrophoresis of genomic DNA extracted from the rat hearts (P<0.001). The ratio of apoptotic nuclei in the cardiomyocytes was significantly higher for the adriamycin-treated rats (162+/-149/10(6) cells) than for the controls (4.2+/-1.3/10(6) cells; P<0.01) by TUNEL assay. Increased endothelial cell apoptosis was detected in the small coronary vessels of the myocardium of the adriamycin-treated rats. Increased immuno-reactive Caspase-3 expression was also noted for both cardiomyocytes and endothelial cells of adriamycin-treated rats. In vitro adriamycin treatment for cultured neonatal rat cardiomyocytes and human umbilical vein endothelial cells, respectively, showed a dose-related increase in apoptosis as determined by flowcytometry, DNA ladder analysis, TUNEL assay and/or electron-microscope examination. A dose-related increase in the expression of Fas antigen, Bax and Caspase-3, as well as a decrease in the expression of Bcl-2, were determined for the adriamycin-treated cardiomyocytes using Northern blot analysis, reverse transcriptase polymerase chain reaction (RT-PCR) and ribonuclease protection assay. RT-PCR also revealed increased Fas antigen expression, decreased Bcl-2 expression, and no change in Bax expression for the adriamycin-treated human umbilical vein cells. Further, pretreatment with broad caspase inhibitor, but not neutralizing FasL antibody, resulted in inhibition of adriamycin-induced endothelial cell apoptosis. In conclusion, these results indicate that both adriamycin-induced cardiomyocyte and endothelial cell death can occur via apoptosis which is dose-related, and can occur both in vitro and in vivo with changes in the expression of the apoptosis-related genes. Adriamycin-induced endothelial cell apoptosis is mediated by caspase activation but is Fas/FasL signal pathway independent. Our data provides evidence that both cardiomyocyte and endothelial cell apoptosis may play an important role in adriamycin-induced cardiomyopathy.
 ...
PMID:Adriamycin-induced cardiomyocyte and endothelial cell apoptosis: in vitro and in vivo studies. 1250 58


<< Previous 1 2 3 4 5 6 Next >>