Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027960 (mole)
 21,279 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To identify molecules involved in the progression of human melanoma to metastatic disease, autologous primary and metastatic melanoma cells were compared by differential mRNA display. One cDNA, expressed in primary but not in autologous metastatic cells in three different patients, was cloned and characterized, and shown to be the human homologue of the inducible, immediate early TDAG51/PHLDA1 (pleckstrin-homology-like domain family A, member1) gene. Monoclonal antibodies produced against the PHLDA1 protein revealed homogeneous strong expression by benign melanocytic nevi, and progressively reduced expression in primary and metastatic melanomas in vivo. Analysis of stable cDNA transfectants in two different cell lines revealed that constitutive PHLDA1 expression is associated with reduced cell growth, cloning efficiency, and colony formation but not with alterations in cell cycle parameters. However, PHLDA1 expression was associated with increased basal apoptosis as assessed by live cell annexin V binding, terminal deoxynucleotidyltransferase-dependent nucleotide incorporation, and with increased cleavage of poly(ADP-ribose) polymerase and caspase-9. Constitutive PHLDA1 expression greatly enhances the sensitivity of human melanoma cells to the chemotherapeutic agents doxorubicin and camptothecin. These results suggest that PHLDA1 is constitutively expressed by melanocytic nevi where it may contribute to their benign phenotype. The progressive loss of PHLDA1 expression in melanomas may play a role in deregulated cell growth and apoptosis resistance in these tumors.
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PMID:Identification of the human PHLDA1/TDAG51 gene: down-regulation in metastatic melanoma contributes to apoptosis resistance and growth deregulation. 1238 58

APAF-1 plays a pivotal role in mitochondria-dependent apoptosis, binding to cytochrome c and favoring activation of caspase-9. It has been shown that epigenetic silencing of the APAF-1 gene is a common event in several metastatic melanoma cells in vitro. We determined, by Western blot, variation in the level of expression of APAF-1 in several human melanoma cell lines and, by immunohistochemistry, in a group of 106 histological samples including benign and malignant melanocytic lesions. We observed APAF-1 down-regulation or loss of expression in two metastatic melanoma cell lines, compared to primary melanoma cell lines. The immunohistochemical analysis revealed a significant difference in APAF-1 staining between nevi and melanomas. In addition, we found a significant negative correlation between APAF-1 expression level and tumor thickness and between primary melanomas and metastases. We conclude that loss of APAF-1 expression can be considered as an indicator of malignant transformation in melanoma.
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PMID:Analysis of APAF-1 expression in human cutaneous melanoma progression. 1500 2

Defects in apoptotic system may contribute in the pathogenesis and resistance of malignant melanoma cells to chemotherapy. Apoptotic protease-activating factor-1 (Apaf-1) is a cell death effector that acts with cytochrome c and caspase-9 to mediate apoptosis. Recently it was shown that metastatic melanomas often lose Apaf-1 and are concomitantly resistant to apoptosis. It is not known, however, whether Apaf-1 protein is lost during melanoma progression from localized to metastatic tumor. To this end, we evaluated Apaf-1 protein expression by immunohistochemistry in 10 cases of human nevi, 11 melanomas in situ, 26 primary melanomas and 15 metastases. Significant decreases in Apaf-1 expression was observed when comparing nevi and melanomas (chi-square = 33.719; P < 0.0001). Moreover, primary melanomas with greater tumor thickness showed lesser expression of Apaf-1 (chi-square = 16.182; P < 0.003). Intriguingly, we were unable to detect Apaf-1 expression in lesions of metastatic melanomas. These data demonstrated that there is an inverse correlation between Apaf-1 expression and pathologic stage of melanoma. This suggests that the decreased expression of Apaf-1 seen in correlation with melanoma progression renders melanoma more resistant to chemotherapy.
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PMID:Decreased expression of Apaf-1 with progression of melanoma. 1564 54