Expression of cell-cycle mediators in ovarian cancer cells after transfection with p16^INK4a, p21^WAF1/Cip-1, and p53

Objective. The purpose of this study was to determine whether transfection of ovarian cancer cell lines with recombinant adenoviral vectors containing wild-type p16^INK4a, p21^WAF1/Cip-1, and p53 caused growth inhibition and induction of apoptosis. We also measured the expression of the cell-cycle mediators Bax, Bcl-2, pRb, and mdm-2. Methods. We introduced the wild-type p16^INK4a, p21^WAF1/Cip-1, and p53 genes into the ovarian cancer cell lines SK-OV-3 (p16^INK4a and p53 null) and OVCA-420 (p16^INK4a and p53 wild-type) by adenoviral transfection. Cell growth inhibition was measured over a 10-day period. Induction of apoptosis was tested for both cell lines 48 h after cell transfection. Expression of cell-cycle mediators was evaluated by Western blot analysis and densitometry. Results. Growth inhibition was documented after transfection with p16^INK4a, p21^WAF1/Cip-1 and p53 in both SK-OV-3 cells and OVCA-420 cells. Apoptosis was greatest in SKOV-3 cells after transfection with p53. A significant expression of Bax was only seen in the SKOV-3 cells transfected with p53. The bcl-2 protein was poorly expressed in both cell lines. Expression of pRb was suppressed in OVCA-420 cells transfected with p16^INK4a and p21^WAF1/Cip-1. Infection with Adp16^INK4a and Adp53 led to an increase in the level of mdm-2 in the SK-OV-3 cell line only. Conclusions. In the ovarian cancer cell lines studied, cell growth was inhibited after transfection with p16^INK4a, p21^WAF1-Cip-1 and p53. Cell cycle arrest was highest with p53 transfection. The expression of pro-apoptosis proteins was primarily a function of p53 expression.