Resveratrol suppresses growth of human ovarian cancer cells in culture and in a murine xenograft model: eukaryotic elongation factor 1A2 as a potential target.

The eukaryotic elongation factor 1A2 (eEF1A2) is known to retain oncogenic potential and is recognized as a novel target for cancer prevention and therapy. Resveratrol (trans-3,4',5-trihydroxystilbene), a phytoalexin present in grapes, has been reported to possess chemopreventive and chemotherapeutic activities. In the present study, we examined the growth-inhibitory effects of resveratrol in human ovarian cancer PA-1 cells, considering eEF1A2 as a potential molecular target. Pretreatment with resveratrol attenuated proliferation of serum-starved PA-1 cells stimulated with insulin or serum. Resveratrol also activated caspase-9, -7, and -3 and induced apoptosis in PA-1 cells in the presence of insulin or serum. Insulin or serum stimulation of PA-1 cells resulted in the marked induction of eEF1A2, which was suppressed by pretreatment with resveratrol. Moreover, resveratrol inhibited insulin- or serum-induced soft-agar colony formation in eEF1A2-transfected NIH3T3 cells. An antibody array directed to assess the phosphorylation of protein kinases revealed that treatment with insulin or serum induced the phosphorylation of Akt in PA-1 cells. Pharmacologic inhibition of Akt with LY294002 abrogated insulin- or serum-induced eEF1A2 expression and increased the caspase-3 activity. In another experiment, i.p. administration of resveratrol retarded the growth of PA-1 cell xenograft and the expression of eEF1A2 in athymic nude mice in association with decreased bromodeoxyuridine positivity, reduced expression of proliferating cell nuclear antigen, increased the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling and caspase-3 staining, and diminished CD31 positivity. Taken together, eEF1A2 may be considered as a potential molecular target for the antiproliferative effects of resveratrol in PA-1 ovarian cancer cells.