Human prostate cancer cells lack feedback regulation of low-density lipoprotein receptor and its regulator, SREBP2

Androgen‐mediated cholesterol metabolism in LNCaP and PC‐3 cell lines is regulated through two different isoforms of acyl‐coenzyme A: Cholesterol Acyltransferase (ACAT)

“…Over-production of LDLr is an essential mechanism in cancer cells to obtain more essential fatty acids through LDLr endocytosis, allowing increased synthesis of prostaglandins, which subsequently stimulate cell growth [35]. The higher LDLr expression in PC-3 cells compared to LNCaP cells may contribute to their faster growth rate.…”

Lipoproteins and Cancer

“…Uptake of cholesterol from LDL is primarily through the LDLR, although several scavenger receptors may also contribute. Over-expression of LDLR without feedback regulation by cholesterol has been observed in many types of cancer cells (Chen, Li et al 1988;Hirakawa, Maruyama et al 1991;Chen and Hughes-Fulford 2001;Antalis, Uchida et al 2011). Although the role of SREBPs in feedback regulation of LDLR expression is well understood (Goldstein, DeBose-Boyd et al 2006), there is evidence that cell signaling pathways also contribute to LDLR up-regulation in cancer.…”

“…The n-6 fatty acid arachidonic acid is necessary for synthesis of second messengers such as the prostaglandin PGE2, a tumor promoter (Wang and Dubois 2006). In androgen-independent PrC PC-3 cells, PGE2 production increased >3-fold in response to LDL (Chen and Hughes-Fulford 2001). Thus the fatty acids esterified to cholesterol and other lipids may be important for the effect of LDL on cancer cells.…”

Diurnal Variation in Growth Hormone Receptor Messenger Ribonucleic Acid in Liver and Skeletal Muscle of lit/+ and lit/lit Mice

“…Primer sequences and the expected size of RT-PCR products are as follows: GHR (forward: 5'-GATTTTACCCCCAG TCCCAGTTC-3', reverse: 5'-GACCCTTCAGTCTT CTCATCCACA-3', product 198 bp), IGF-I (forward: 5'-GTGTGGACC GAGGGGCTTTTACTT C-3', reverse: 5'-GCTTCAGTGGGGCACAGTACATCT C-3', product 146 bp), and 18S rRNA (forward: 5'-TCAA GAACGAAAGTCGGAGG-3', reverse: 5'-GGACAT CTAAGGGCATCACA-3', product 489 bp). The primers of 18S rRNA were designed as previously reported [17]. The primer pairs to amplify the GHR coded exclusively for GHR and not for GHBP since they were directed to the intracellular domain of GHR.…”