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)

Normal human melanocytes have been shown to respond to the signal peptide endothelin by increased proliferation and melanin formation. Contradictory findings, however, have been reported about which of the two endothelin receptors (EDNRA or EDNRB) is expressed in normal melanocytes and melanoma cells. Moreover it was not clear whether malignant cells differ from their normal precursors in this respect. Screening a melanocyte cDNA library for genes downregulated in melanomas identified clones specific for EDNRB. Northern blots proved that the corresponding mRNA is generally expressed in cultures of human cutaneous melanocytes and congenital melanocytic nevus cells. In 16 of 17 melanoma cell lines, however, the expression of EDNRB mRNA was strongly downregulated. EDNRA was only weakly expressed and detectable by northern blotting in 12 of 17 cultures of benign melanocytic cells and four of 17 melanoma cell lines. Nested reverse transcriptase-polymerase chain reaction proved several melanoma cell lines to be completely negative for EDNRA expression. Gene deletion as the cause of missing endothelin receptor expression was ruled out by genomic Southern blots. Receptor binding assays confirmed RNA data revealing 1.6 x 105 endothelin-1 binding sites per cell for a melanocyte culture and between 8.7 x 104 and 400 sites per cell for melanoma cell lines. Expression of pigmentation genes coding for tyrosinase, TRP-1 and TRP-2 correlated positively with that of EDNRB but negatively with EDNRA expression. EDNRB but not EDNRA expression is therefore typical for melanocytic cells, and downregulation of EDNRB seems to be an important characteristic of melanoma cells possibly related to malignancy or apoptosis.
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PMID:Downregulation of endothelin B receptor in human melanoma cell lines parallel to differentiation genes. 1038 40

Melanocyte differentiation antigens, such as gp100, tyrosinase, and Melan-A and their corresponding antibodies HMB45, T311, and A103, are major diagnostic tools in surgical pathology. Little is known about tyrosinase-related protein 2 (TRP-2, or dopachrome tautomerase/DCT) another melanocyte differentiation antigen, which is an enzymatic component of melanogenesis. We identified a commercial reagent to TRP-2, monoclonal antibody (mAb) C-9 and undertook a comprehensive analysis to assess its specificity and usefulness for surgical pathology. Subsequently, we analyzed panels of normal tissues and tumors. We show that TRP-2 is regularly expressed in melanocytes of the normal skin. In cutaneous nevi, TRP-2 is present in junctional as well as in dermal nevocytes. In malignant tumors, C-9 reactivity is restricted to melanocytic and related lesions and present in 84% and 58% of primary and metastatic melanomas, respectively. Ten primary melanomas of the anorectal mucosa were all positive. Like the other melanocyte differentiation antigens, TRP-2 was absent in 6 desmoplastic melanomas. Also, only 2 of 9 angiomyolipomas were TRP-2 positive. We conclude that mAb C-9 is a valuable reagent for the analysis of TRP-2 expression in archival surgical pathology material. The expression pattern of TRP-2 in melanocytic and related lesions appears to parallel other melanocyte differentiation antigens, although the overall incidence is lower than other antigens, such as Melan-A or gp100.
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PMID:Protein Expression Analysis of Melanocyte Differentiation Antigen TRP-2. 2689 71