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)

Thirty-one cases of small cell lung carcinomas (SCLC) were investigated by immunohistochemistry for the expression of bcl-2, p53 and the wild-type (wt) p53- induced proteins mdm2 and p21/waf1. Bcl-2 protein was detected in 24/31 cases of SCLC(77%) and p53 protein in 13/31 cases (42%). No correlation was found between histological subtype of SCLC and bcl-2 or p53 expression. Comparison between bcl-2 and p53 expression showed that 14/31 cases (45%) were only bcl-2 positive, 3/31 (11%) were only p53 positive, 10/31 (32%) were positive for both proteins and 4/31 (13%) were negative for both proteins. Mdm2 protein was detected in 2/32 SCLC which were also p53 positive. P21 protein was detected in 6/32 SCLC. Four of the p21 positive SCLC were negative for both p53 and mdm2, and two were positive for both p53 and mdm2 proteins. The significant expression of bcl-2 protein in SCLC suggests that bcl-2 may be involved in the pathogenesis of most SCLC by inhibiting apoptosis during neoplastic transformation. The expression of p53 protein in SCLC is likely to be related to underlying p53 gene mutations since these genetic alterations are very frequent in SCLC. This can be supported by our findings that 11/13 p53 positive SCLC were mdm2 and p21 negative. The two cases with p53+/mdm2+/p21+ phenotype may represent tumours with wt p53 gene and p53 protein immunoexpression due to binding to mdm2 protein. The four cases with p53-/mdm2-/p21+ phenotype may represent tumours with p53-independent p21 protein expression. Coexpression of p53 and bcl-2 proteins in a proportion of SCLC suggests that in these tumours p53 doses not maintain its suppressive effect on bcl-2 expression as it has been reported in vitro. Further studies at DNA and RNA level are required to clarify the involvement of bcl-2, p53, mdm2 and waf1 genes in SCLC pathogenesis.
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PMID:Immunohistochemical detection of bcl2, p53, mdm2 and p21/waf1 proteins in small-cell lung carcinomas. 961 83

Thirty-one cases of small cell lung carcinomas (SCLC) were investigated by immunohistochemistry for the expression of bcl-2. P53 and the wild-type (wt) p53-induced proteins mdm2 and p21/waf1. Bcl-2 protein was detected in 24/31 cases of SCLC(77%) and p53 protein in 13/31 cases (42%). No correlation was found between histological subtype of SCLC and bcl-2 or p53 expression. Comparison between bcl-2 and p53 expression showed that 14/31 cases (45%) were only bcl-2 positive, 3/31 (11%) were only p53 positive, 10/31 (32%) were positive for both proteins and 4/31 (13%) were negative for both proteins. Mdm2 protein was detected in 2/32 SCLC which were also p53 positive. P21 protein was detected in 6/32 SCLC. Four of the p21 positive SCLC were negative for both p53 and mdm2, and two were positive for both p53 and mdm2 proteins. The significant expression of bcl-2 protein in SCLC suggests that bcl-2 may be involved in the pathogenesis of most SCLC by inhibiting apoptosis during neoplastic transformation. The expression of p53 protein in SCLC is likely to be related to underlying p53 gene mutations since these genetic alterations are very frequent in SCLC. This can be supported by our findings that 11/13 p53 positive SCLC were mdm2 and p21 negative. The two cases with p53+/mdm2+/p21+ phenotype may represent tumours with wt p53 gene and p53 protein immunoexpression due to binding to mdm2 protein. The four cases with p53-/mdm2-/p21+ phenotype may represent tumours with p53-independent p21 protein expression. Coexpression of p53 and bcl-2 proteins in a proportion of SCLC suggests that in these tumours p53 does not maintain its suppressive effect on bcl-2 expression as has been reported in vitro. Further studies at the DNA and RNA level are required to clarify the involvement of bcl-2, p53, mdm2 and wafl genes in SCLC pathogenesis.
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PMID:Immunohistochemical detection of bcl2, p53, mdm2 and p21/waf1 proteins in small-cell lung carcinomas. 967 91

We treated primary epithelial cells from human normal prostate (NEPC) and prostate cancer (CEPC) with all-trans-retinoic acid (RA) to study whether it regulates the activity of tissue transglutaminase (tTGase), an enzyme that accumulates in cells undergoing apoptosis. tTGase activity was assessed by [14C]spermidine incorporation; tTGase, P53, Bcl-2, and p21 protein levels were evaluated by Western blotting; and RA receptors (RAR alpha, -beta, and -gamma), tTGase, retinol-binding protein (RBP), and cellular RBP type I transcripts were determined by semiquantitative RT-PCR. After 72-96 h of 10(-6) mol/L RA treatment, cell growth inhibition and apoptosis were associated with increased tTGase activity in both NEPC and CEPC, and with increased tTGase protein and messenger ribonucleic acid levels only in NEPC. Moreover, RA down-regulated RAR alpha and -beta and increased RBP messenger ribonucleic acid levels in NEPC, whereas it increased RAR beta gene expression and decreased Bcl-2 protein levels in CEPC. Our results suggest that RA induces tTGase gene expression and enzyme activity in normal prostate cells, and that RA-regulated pathways are impaired in cancer cells. Moreover, down-regulation of Bcl-2 protein and up-regulation of RAR beta suggest that retinoid may act on the genetic defect responsible for prostate cancer progression.
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PMID:Changes in tissue transglutaminase activity and expression during retinoic acid-induced growth arrest and apoptosis in primary cultures of human epithelial prostate cells. 1019 96

As tumours are known to acidify their microenvironment and fluctuations in lumenal pH have been reported in a number of colonic disease conditions, we investigated whether loss of p53 function, commonly associated with the adenoma to carcinoma transition in human colorectal epithelium, was implicated in the cellular response to changes in extracellular pH. Human colonic adenoma and carcinoma derived cell lines were incubated at an initial pH range of 5.5-8.0 and the attached cell yield and apoptotic cell yield determined after 4 days. Exposure of all cell lines to an acidic growth environment was associated with a G1 arrest, down regulation of the retinoblastoma protein (pRb) protein and switch to the hypophosphorylated form of the protein, and increased expression of the p21 protein. However, induction of apoptosis, associated with increased p53 protein expression but not with changes in Bcl-2 expression, was only detected in the adenoma derived BH/C1 and AA/C1 cell lines which express wild type p53 activity. Furthermore, this induction of apoptosis was inhibited in the transfected cell line AA/273p53/B, in which the wild type p53 function has been abrogated. These results suggest that acidification of the microenvironment would provide a selective growth advantage for cells that have lost wild type p53 function, leading to clonal expansion of aberrant cell populations.
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PMID:An acidic environment leads to p53 dependent induction of apoptosis in human adenoma and carcinoma cell lines: implications for clonal selection during colorectal carcinogenesis. 1035 25

In order to define the roles of p53 in acquisition of drug resistance in ATL cell lines, we prepared several ATL cell lines which differed in sensitivity to adriamycin (ADM), and examined their functional p53 statuses, expressions of p53, p21, Bcl-2, Bax, and cell cycles. Our findings demonstrated: (1) Regardless of sensitivity to ADM, most of the cell lines, including ADM-resistant cell lines, carried wild-type p53. (2) Only one cell line, ED-S, which was the most sensitive to ADM carried non-functional mutated-type p53. (3) In the ATL cells carrying wild-type p53, regardless of sensitivity to ADM, ADM-treatment led to an elevation of p53 protein level with concomitant elevations of p21 and Bax protein levels. (4) In the cell line expressing mutated-type p53, ADM-treatment at the concentration of IC50 induced elevations of p53, and Bax protein levels but did not p21 protein level. (5) Expression of Bcl-2 protein did not change in any of the cell lines by treatment with ADM at their respective IC50 levels, but increased in the ADM-resistant cell line when it was treated with ADM at IC50 of its parent cell line. (6) In the cell cycle analysis, ADM-treatment induced G1- and G2-arrest and then apoptosis in the cell lines with wild-type p53, whereas it induced only G2-arrest and then apoptosis in the cell line with mutated-type p53 at the same time course as in those with wild-type p53. These findings suggest that p53 does not play a leading part either in the apoptosis induced by ADM, or in the acquisition of resistance to ADM in ATL cells, and that ADM-induced apoptosis is mediated by multiple pathways leading to the activation of effector molecules.
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PMID:[Roles of p53 in adriamycin-induced cell death and in acquisition of adriamycin resistance in adult T-cell leukemia (ATL) cells]. 1042 67

The effects of 24-hr exposures to 5-fluorouracil (FUra) and paclitaxel in various sequences were studied in MCF-7 breast cancer cells to determine an optimal schedule for possible clinical use. In clonogenic assays, pre-exposure to FUra followed by paclitaxel resulted in marked antagonism, while sequential paclitaxel followed by FUra was optimal. Concurrent or pre-exposure to paclitaxel did not affect [3H]FUra metabolism, [3H]FUra-RNA incorporation, or the extent of FUra-mediated thymidylate synthase inhibition. Paclitaxel led to G2/M phase accumulation that persisted for up to 24 hr after drug exposure, while a 24-hr FUra exposure produced S-phase accumulation. FUra pre-exposure diminished paclitaxel-associated G2/M phase block, whereas subsequent exposure to FUra after paclitaxel did not. FUra exposure resulted in transient induction of p53 and p21, which returned to basal levels 24 hr after drug removal. p53 and p21 protein content also increased markedly during paclitaxel exposure, accompanied by phosphorylation of Bcl-2. Double-stranded DNA fragmentation (approximately 50 kb) was seen at 48 hr when cells were exposed to paclitaxel for an initial 24-hr period. Paclitaxel-associated DNA fragmentation was not prevented by concurrent or subsequent exposure to FUra. Thus, paclitaxel-mediated G2/M phase arrest appeared to be a crucial step in induction of DNA fragmentation. Since an initial 24-hr paclitaxel exposure did not interfere with subsequent FUra metabolism or thymidylate synthase inhibition, and delayed exposure to FUra did not impede either paclitaxel-mediated induction of mitotic blockade or DNA fragmentation, the sequence of paclitaxel followed by FUra is recommended for clinical trials.
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PMID:Sequence-dependent antagonism between fluorouracil and paclitaxel in human breast cancer cells. 1042 68

Growth of human breast adenocarcinoma MCF-7 cells as a tumor on nude mice is dependent on estrogen. It has been shown that estrogen withdrawal (EW) induces a partial regression of the tumor via an inhibition of cell proliferation and an induction of apoptosis. We investigated in this in vivo model the underlying molecular mechanisms of the hormone-dependent regulation of cell cycle machinery and apoptosis. We found that, 2 days after EW, the tumor protein levels of p21 rose, whereas those of Rb proteins decreased in parallel with the decrease in the proportion of tumor cells in S phase and the increase of the tumor apoptotic index. Between 3 and 7 days after EW, apoptosis was inhibited and tumor proliferation returned to the control value. There was a concomitant decline in p21 and an elevation of Rb tumor protein content. Slight variations of cyclin D protein level were observed in MCF-7 tumors over the time course following EW treatment. Bcl-2 overexpression not only inhibited apoptosis induced by EW but also modulated hormone-dependent cell cycle regulation. First, the analysis of phosphorylation status of Rb protein and the measurement of the proportion of tumor cells in S phase indicated that Bcl-2 overexpression results in a decrease of DNA synthesis induced by estradiol. Furthermore, after EW, Bcl-2-induced inhibition of hormone-dependent apoptosis was associated with an inhibition of Rb protein downregulation, a sustained level of p21 protein, and a prolonged inhibition of cell cycle progression. These results suggest that, in human hormone-dependent breast cancers, cross-talk exists between the signaling pathways which lead to regulation of cell cycle progression and apoptosis.
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PMID:Interconnections between E2-dependent regulation of cell cycle progression and apoptosis in MCF-7 tumors growing on nude mice. 1064 Apr 22

Early-passage human diploid fibroblasts (HDFs) undergo senescence-like growth arrest in response to sublethal concentrations of H(2)O(2) [Chen and Ames (1994) Proc. Natl. Acad. Sci. USA. 95, 4130-4134]. We determine here whether H(2)O(2) can cause apoptosis in HDFs and the molecular changes that differ between apoptosis and senescence-like growth arrest. When exponentially growing early-passage IMR-90 cells were treated for 2 h with 50-200 microM (or 0.25-1 pmol/cell) H(2)O(2), a fraction of cells detached at 16-32 h after the treatment. The cells remaining attached were growth-arrested and developed features of senescence in 1 week. The detached cells showed caspase-3 activation and typical morphological changes associated with apoptosis. Caspase-3 activation was H(2)O(2) dose-dependent and preceded nuclear condensation or plasma membrane leakage. Apoptotic cells were mainly distributed in the S-phase of the cell cycle, while growth-arrested cells exhibited predominantly G1- and G2/M-phase distributions. H(2)O(2) pretreatment induced G1 arrest and prohibited induction of apoptosis by a subsequent H(2)O(2) challenge. The p53 protein showed an average 6.1-fold elevation in apoptotic cells and a 3.5-fold elevation in growth-arrested cells. Reduction of p53 levels with human papillomavirus E6 protein prohibited the activation of caspase-3 and decreased the proportion of apoptotic cells. Growth-arrested cells had elevated p21, while p21 was absent in apoptotic cells. Bcl-2 was elevated in both growth-arrested and apoptotic cells. Finally, although the overall level of bax did not change in growth-arrested or apoptotic cells, the solubility of bax protein increased in apoptotic cells. Our data suggest that in contrast with growth-arrested cells, apoptotic cells show an S-phase cell cycle distribution, a higher degree of p53 elevation, an absence of p21 protein and increased solubility of bax protein.
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PMID:Apoptosis or senescence-like growth arrest: influence of cell-cycle position, p53, p21 and bax in H2O2 response of normal human fibroblasts. 1074 85

Tumour growth is regulated by a balance between proliferation, growth arrest and programmed cell death (apoptosis). Until recently, the majority of the studies dealing with oncogenesis has been focused on the regulation of cell proliferation. There is now growing understanding that control of growth arrest and apoptosis play key roles in the development of human cancer and in cancer treatment. Some of the more heavily studied proteins of importance for the control of growth arrest and apoptosis are p53, p21, bcl-2 and bax. Alterations in the p53 protein may lead to malignant transformation and defect therapy response, most likely as a result of defective p53-dependent apoptosis. In addition, p21 (WAF1/CIP1) is involved in cell-cycle arrest and probably in induction of p53-dependent apoptosis. Proteins belonging to the bcl-2 family are also important for normal apoptosis. Overexpression of bcl-2 protein is thought to reduce the apoptotic capacity, while bax protein seems to be necessary for induction of apoptosis. In this study, we have immunostained tissues from 93 primary colon carcinomas and have examined the expression of p53, p21 (WAF1/CIP1), bcl-2 bax, pRb and cyclin D1 for evaluation of their roles in colon-cancer progression. A highly significant association between p53 accumulation and downregulation of p21 (WAF1/CIP1) was seen. We also found a strong association between reduced/absent p21 and the development of metastases and death due to cancer disease. Cyclin D1, bcl-2 and bax protein failed to have independent prognostic impacts. Bcl-2 and bax protein levels showed an inverse relationship. The results of the present study indicate that reduced p21 protein levels play an important role in progression of colon cancer. We concluded that evaluation of p21 expression in primary colon carcinomas at the time of surgery might be a valuable tool in defining patients with a high risk of developing metastases.
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PMID:Protein expression of p53, p21 (WAF1/CIP1), bcl-2, Bax, cyclin D1 and pRb in human colon carcinomas. 1078 80

The effect of environmental acidity on the induction of apoptosis by heat was investigated. Human colorectal tumour RKO.C cells, carrying wild-type p53 and isogenic RC10.1 cells deficient in p53, were heated at 42.0 degrees C for 1 h in pH 7.5 or pH 6.6 medium and the apoptosis was assessed based on the flow cytometic determination of DNA content, DNA fragmentation, and PARP cleavage. The degree of apoptosis after heating in pH6.6 medium was greater than that in pH 7.5 medium in both RKO.C cells and RC10.1 cells. When heated in the same pH medium, more apoptosis occurred in the RC10.1 cells than in the RKO.C cells. Heating increased the expression of p53 protein and p21 protein markedly in RKO.C cells and slightly in RC10.1 cells. Expression of these proteins was slightly greater in pH 7.5 medium than in pH 6.6 medium. The expressions of Bax protein and Bcl-2 protein, which are known to control apoptosis, were not altered by heating. It was concluded that an acidic environment enhances heat-induced apoptosis. It was also concluded that heat-induced apoptosis is lessened by p53 and that Bcl-2 and Bax are not involved in the induction of apoptosis by hyperthermia.
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PMID:Effect of acidic environment and p53 on apoptosis induction by hyperthermia. 1112 60


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