Abstract
Endothelin-1 (ET-1) is a potent vasoconstrictor that has been shown to significantly impact many benign and malignant tissues by signaling through its two cognate receptors: ET(A) and ET(B). As ET-1 has a role in both normal and diseased kidney, we initiated studies to investigate endothelin axis expression and function in renal cell carcinoma (RCC). In this study, relatively high levels of ET-1 were detected in all six human RCC cell lines investigated. RT-PCR and Southern analyses revealed that all six RCC cell lines expressed ET(A) receptor mRNA, while 3/6 cell lines also expressed ET(B) mRNA. High affinity ET-1 binding occurred in all but one RCC cell line and quantitative RT-PCR demonstrated ET(A) mRNA expression in all six cell lines. Methylation of the ET(B) promoter (EDNRB) in 4/6 RCC cell lines was observed, suggesting a mechanism for repressed ET(B) expression. Moreover, methylation occurred in 32/48 of renal tumors and in 27/55 of histologically normal adjacent tissue samples studied, while no methylation was evident in any normal tissue isolated from nephrectomy or at autopsy. Functionally, ET-1 significantly inhibited paclitaxel-induced apoptosis in RCC cells through binding ET(A) with the ET-1 signaling mediated via the PI3-kinase/Akt pathway. Collectively, these data support the therapeutic targeting of the ET(A) receptor as a novel treatment strategy for RCC.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Androstadienes / pharmacology
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Antineoplastic Agents, Phytogenic / pharmacology
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Apoptosis / drug effects
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Carcinoma, Renal Cell / genetics
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Carcinoma, Renal Cell / metabolism
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Carcinoma, Renal Cell / pathology
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Cell Line, Tumor
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Cell Survival / drug effects
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Chromones / pharmacology
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DNA Methylation
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Endothelin A Receptor Antagonists
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Endothelin-1 / metabolism*
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Endothelin-1 / pharmacology
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Endothelin-1 / physiology
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Enzyme-Linked Immunosorbent Assay
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Gene Expression Regulation, Neoplastic*
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Humans
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Immunoblotting
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Kidney Neoplasms / genetics
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Kidney Neoplasms / metabolism
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Kidney Neoplasms / pathology
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Morpholines / pharmacology
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Paclitaxel / pharmacology
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Phosphatidylinositol 3-Kinases / metabolism
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Phosphoinositide-3 Kinase Inhibitors
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Phosphorylation / drug effects
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Promoter Regions, Genetic
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Protein Binding
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Proto-Oncogene Proteins c-akt / metabolism
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RNA, Messenger / genetics
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RNA, Messenger / metabolism
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Receptor, Endothelin A / agonists
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Receptor, Endothelin A / genetics*
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Receptor, Endothelin B / genetics
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Reverse Transcriptase Polymerase Chain Reaction
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Signal Transduction / drug effects
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Wortmannin
Substances
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Androstadienes
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Antineoplastic Agents, Phytogenic
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Chromones
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Endothelin A Receptor Antagonists
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Endothelin-1
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Morpholines
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Phosphoinositide-3 Kinase Inhibitors
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RNA, Messenger
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Receptor, Endothelin A
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Receptor, Endothelin B
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2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one
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Proto-Oncogene Proteins c-akt
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Paclitaxel
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Wortmannin