Inhibitory effect of Epigallocatechin gallate on ovarian cancer cell proliferation associated with aquaporin 5 expression.

OBJECTIVE: Abnormal expression of aquaporin 5 (AQP5) is associated with ovarian cancer infiltration, metastasis and angiogenesis. AQP 5 expression and apoptosis have been shown to be closely related to nuclear transcription factor NF-κB. In this study, we investigated the inhibition of cell proliferation and the induction of apoptosis by Epigallocatechin gallate (EGCG), a potential anti-cancer drug, in the ovarian cancer cell line SKOV3 as well as the effect of EGCG on AQP5 expression and its possible mechanisms.
METHODS: SKOV3 cells were treated with different concentrations of EGCG and the NF-κB-specific inhibitor pyrrolidine dithiocarbamate (PDTC) for different times. Cell proliferation was determined using the MTT assay, cell apoptosis was evaluated using the DNA ladder assay, the expression of AQP5, NF-κB p65 and IκBα was detected by immunohistochemistry, western blot analysis and RT-PCR, and the correlation of these protein expression was analyzed.
RESULTS: With increasing concentrations of EGCG and prolonged treatment times, the growth inhibition rate of SKOV3 cells gradually increased in a dose- and time-dependent manner. The expression of AQP5 and nuclear p65 and IκBα was significantly decreased (P < 0.01). The cytoplasmic expression of IκBα gradually increased (P < 0.05), and the apoptosis of SKOV3 cells was induced as evidenced by typical fragmentation pattern in a DNA ladder assay. With increasing concentrations of PDTC and prolonged treatment times, the protein and mRNA levels of AQP5 in SKOV3 cells decreased (P < 0.01). In addition, the growth inhibition rate of SKOV3 cells significantly increased in a dose- and time-dependent manner.
CONCLUSIONS: EGCG inhibited the proliferation and induced the apoptosis of ovarian cancer SKOV3 cells. EGCG also down-regulated expression of AQP5, which may inhibit tumor growth and be associated with nuclear transcription factor NF-κB.