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Human prostate cancer cells lack feedback regulation of low‐density lipoprotein receptor and its regulator, SREBP2
Author(s) -
Chen Yunfei,
HughesFulford Millie
Publication year - 2000
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/1097-0215(20010101)91:1<41::aid-ijc1009>3.0.co;2-2
Subject(s) - ldl receptor , prostate cancer , cancer cell , biology , sterol regulatory element binding protein , regulator , endocytosis , endocrinology , low density lipoprotein , sterol , medicine , cancer , receptor , cancer research , microbiology and biotechnology , cholesterol , lipoprotein , biochemistry , gene
The low‐density lipoprotein receptor (LDLR) pathway provides cells with essential fatty acids for prostaglandin E 2 (PGE 2 ) synthesis. Regulation of LDLR expression by LDL was compared between the human normal and cancer prostate cells using semi‐quantitative RT‐PCR and LDL uptake assays. LDLR mRNA expression and LDL uptake by LDLR were down‐regulated in the presence of exogenous LDL or whole serum in the normal prostate cells, but not in the prostate cancer cells. Addition of exogenous cholesterol down‐regulated both LDLR and a potent regulator of the ldlr promoter, sterol regulatory element binding protein 2 (SREBP2), in normal cells but not in cancer cells. PGE 2 synthesis in prostate cancer cells was significantly increased in response to LDL. Our study suggests that over‐production of LDLR is an important mechanism in cancer cells for obtaining more essential fatty acids through LDLR endocytosis, allowing increased synthesis of prostaglandins, which subsequently stimulate cell growth. The data also suggest that the sterol regulatory element and SREBP2 play a role in the loss of sterol feedback regulation in cancer cells. Int. J. Cancer 91:41–45, 2001. © 2001 Wiley‐Liss, Inc.