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Caveolin-1 (Cav), a primary protein component of caveolae, is overexpressed in prostate cancer, thereby promoting growth and metastasis of this tumor. By contrast, pigment epithelium-derived factor (PEDF) has been shown to inhibit tumor growth and metastasis, including that of prostate cancer, via its anti-angiogenic and anti-inflammatory effects. Although it was recently demonstrated that PEDF binds to Cav and blocks its pro-inflammatory actions in endothelial cells, it remains unclear whether PEDF also inhibits the tumor-promoting effects of Cav in cultured prostate cancer cells. The present study examined the effects of PEDF on cell growth, in addition to the gene expression of interleukin-8 (IL-8), which is involved in prostate cancer progression, in the PC-3 human prostate cancer cell line. Exogenous Cav led to a dose-dependent upregulation of the mRNA expression of IL-8 in PC-3 cells, which was blocked by treatment with 1 or 10 nM PEDF, or following the overexpression of small interfering RNAs directed against Cav. Cav (10 nM) increased DNA synthesis in PC-3 cel ls, which was again suppressed by the administration of 10 nM PEDF. The results of the present study indicated that PEDF may inhibit Cav-induced increases in IL-8 gene expression and proliferation of PC-3 cells. Therefore, the suppressive effects of PEDF in prostate cancer may, in part, be ascribed to its inhibitory actions on Cav. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the effects of ethanol on the expression of caveolin-1 (CAV-1) in HepG2 hepatocarcinoma cells. Ethanol-treated HepG2 cells were investigated using the in vitro model to determine whether ethanol can influence the expression of CAV-1. Cell viability was measured using the colorimetric 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and lactate dehydrogenase (LDH) assays. Expression of CAV-1 was detected using western blot analysis. Quantitative PCR (qPCR) was used to determine CAV-1 mRNA levels. The distribution of CAV-1 in HepG2 cells was analyzed using immunofluorescence. The MTT assay results revealed that cell viability was not altered at ethanol concentrations of <1.0%, while ethanol concentrations >1.0% caused cell shedding, but not cell fragmentation. Western blot analysis showed significant differences in the levels of CAV-1 expression between the control group and the 1.0% ethanol-treated group at 6, 12 and 24 h (all P<0.05). qPCR showed significant differences in the expression levels of caveolin-1 mRNA between the control group and the 1.0% ethanol-treated group at 6 h, 12 h and 24 h (all P<0.05). Immunofluorescence demonstrated that CAV-1 was distributed discontinuously at the boundaries of HepG2 cells. The results indicate that ethanol may increase the expression of CAV-1 in HepG2 cells. [ABSTRACT FROM AUTHOR]