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)

Malignant transformation occurs in cells that overexpress c-Myc or that inappropriately activate E2F-1. Transformation occurs after the selection of cells that have acquired resistance to apoptosis that is triggered by these oncogenes, and a key mediator of this cell death process is the p53 tumor suppressor. In IL-3-dependent immortal 32D.3 myeloid cells the ARF/p53 apoptotic pathway is inactivated, as these cells fail to express ARF. Nonetheless, both c-Myc and E2F-1 overexpression accelerated apoptosis when these cells were deprived of IL-3. Here we report that c-Myc or E2F-1 overexpression suppresses Bcl-2 protein and RNA levels, and that restoration of Bcl-2 protein effectively blocks the accelerated apoptosis that occurs when c-Myc- or E2F-1-overexpressing cells are deprived of IL-3. Blocking p53 activity with mutant p53 did not abrogate E2F-1-induced suppression of Bcl-2. Analysis of immortal myeloid cells engineered to overexpress c-Myc and E2F-1 DNA binding mutants revealed that DNA binding activity of these oncoproteins is required to suppress Bcl-2 expression. These results suggest that the targeting of Bcl-2 family members is an important mechanism of oncogene-induced apoptosis, and that this occurs independent of the ARF/p53 pathway.
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PMID:Bcl-2 is an apoptotic target suppressed by both c-Myc and E2F-1. 1170 23

Malignant transformation of endometriosis, an uncommon phenomenon, can occur in gonadal and extragonadal sites and results in a wide histological range of tumors. Published series reporting malignant transformation of endometriosis have largely been confined to clinical and histopathological discussions with no studies reporting oncoprotein expression and genetic alterations. We report three cases of carcinomas arising in ovarian endometriosis: a serous cystadenocarcinoma, an endometrioid carcinoma with squamous differentiation, and a pure squamous cell carcinoma. Each tumor was analyzed immunohistochemically to compare oncoprotein expression (p53, bcl2, cyclin D1, and c-erb B2) between the tumors and the endometriotic tissue as well as with comparative genomic hybridization (CGH) to compare genetic alterations. All three tumors expressed nuclear p53, in contrast to the endometriotic tissue in which no p53 expression was found. Both endometrial and tumor tissue expressed bcl-2. No expression of cyclin D1 or c-erb B2 was detected in endometriotic or tumoral tissues. The CGH analysis revealed one or two chromosomal aberrations in each of the three tumors with gains on chromosomes 1q, 8q, and 13q, and losses on chromosome 10p. The endometriotic tissue, as expected, showed a normal genetic profile. These results suggest that p53 protein abnormalities and chromosomal aberrations may be involved in malignant transformation of endometriosis in the ovary. However, our results are limited by the number of cases examined and a definite conclusion on the pathogenesis of this process should be followed by future studies with a larger number of cases.
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PMID:Ovarian carcinomas in endometriosis: an immunohistochemical and comparative genomic hybridization study. 1235 89

The HTLV-1 transactivator protein Tax is essential for malignant transformation of CD4 T cells, ultimately leading to adult T-cell leukemia/lymphoma (ATL). Malignant transformation may involve development of apoptosis resistance. In this study we investigated the molecular mechanisms by which HTLV-1 Tax confers resistance toward CD95-mediated apoptosis. We show that Tax-expressing T-cell lines derived from HTLV-1-infected patients express elevated levels of c-FLIP(L) and c-FLIP(S). The levels of c-FLIP correlated with resistance toward CD95-mediated apoptosis. Using an inducible system we demonstrated that both resistance toward CD95-mediated apoptosis and induction of c-FLIP are dependent on Tax. In addition, analysis of early cleavage of the BH3-only Bcl-2 family member Bid, a direct caspase-8 substrate, revealed that apoptosis is inhibited at a CD95 death receptor proximal level in Tax-expressing cells. Finally, using siRNA we directly showed that c-FLIP confers Tax-mediated resistance toward CD95-mediated apoptosis. In conclusion, our data suggest an important mechanism by which expression of HTLV-1 Tax may lead to immune escape of infected T cells and, thus, to persistent infection and transformation.
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PMID:HTLV-1 Tax protects against CD95-mediated apoptosis by induction of the cellular FLICE-inhibitory protein (c-FLIP). 1640 15

In order to correlate changes in morphology to changes in molecular attributes, we constructed a tissue microarray of thin and thick melanomas selected to represent progression from dysplasia to early and advanced melanoma. Hematoxylin and eosin (H&E) staining and immunohistology with antibodies to cyclin D1, p16, Ki67, and Bcl-2 were performed. Observations were interpreted using a revised paradigm for the dysplasia-melanoma sequence in which the early steps of melanomatous growth develop in an accretive fashion similar to the growth of the common acquired nevus. The co-expression of cyclin D1 and p16 persisted from dysplasia to early melanomatous vertical growth. Malignant transformation characterized by absence of p16 and presence of increased cyclin D1 and increased Ki67 and confirmed by clinically documented metastasis occurred during the process of evolving melanomatous vertical growth. The interplay of mutated BRAF, cyclin D1, and p16 with anti-apoptosis and failure of senescence may account for the existence of nevi and dysplastic nevi and for their relationship to melanoma, and may indirectly account for the infrequency of nevi in the lentiginous melanomas that lack mutated BRAF. These observations suggest a need for more detailed study of transformation to malignancy in the various subsets of melanoma.
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PMID:Failure of senescence in the dysplasia-melanoma sequence: demonstration using a tissue microarray and a revised paradigm for melanoma. 1808 70