Cyr61 expression influences cancer cell proliferation and apoptosis via PI3K pathway in human ovarian carcinoma cells

Abstract

To investigate the relationship between cysteine-rich protein 61 (Cyr61) and phosphatidylinositol 3-kinase (PI3K) signal pathway on cell proliferation and apoptotic in human ovarian carcinoma cells. Recombinant human Cyr61 (rhCyr61) was pretreated with ovarian carcinoma cells. The expression of Cyr61 protein was detected by confocal spectral microscopy. Then treated the ovarian carcinoma cells with PI3K transduction inhibitors (LY294002) for 24 hours. Cell apoptosis was detected by flow cytometry (FCM). Cell viability was determined by methyl thiazolyl tetrazolium (MTT) method. The mRNA expressions of Cyr61, the protein levels of protein kinase B (PKB), phospho-PKB and Cyr61 were assayed by real time-PCR and western blot analysis, respectively. The Cyr61 and phospho-PKB protein expression in two ovarian carcinoma cells (OV2008 and OVCAR-3) were increased in rhCyr61 pretreated group. The decreasing of cell apoptosis [(1.4 ± 0.9)%, (2.1 ± 1.0)%] and increasing of cell proliferation [(124.0 ± 1.8)%, (133.0 ± 2.2)%] was detected in the same time, compared with negative control group, there were significant difference (P < 0.05). After exposed to LY294002 for 24 hours, the apoptosis rate of OV2008 and OVCAR-3 in pretreated with rhCyr61 group exposed to LY294002 were (21.1 ± 1.6)% and (26.4 ± 1.5)%, respectively. Cells viability [(59.0 ± 2.3)%, (51.0 ± 2.0)%] was also significantly decreased in OV2008 and OVCAR-3 pretreated with rhCyr61 cells. Meanwhile, the mRNA expressions of Cyr61 (3.2 ± 0.8, 6.2 ± 1.1) and the protein levels of phospho-PKB and Cyr61 were greatly decreased. Compared with negative control group, there were significant difference in OV2008 and OVCAR-3 cells (all P < 0.01). The activation of PI3K intracellular signaling pathways may lead to up-regulation of Cyr61 expression. Block PI3K signal pathway could significantly inhibit the expression of Cyr61, and may promote the apoptotic effects and inhibit the cell growth of ovarian carcinoma cells.