Small interference RNA-mediated suppression of overexpressed cyclin E protein restores G1/S regulation in NIH-OVCAR-3 ovarian cancer cells.

The development of ovarian cancer, unlike that of most human tumors, is rarely dependent upon the mutually exclusive loss of RB and p16 cell cycle proteins. RB+/p16+ ovarian cancer cell lines are, however, insensitive to the growth-suppressive effects of ectopically expressed p16 protein, which suggests that they harbor as yet unidentified defects that compromise cell cycle regulation in late G1/S. In the current study, we used Western blotting to analyze cyclin E protein expression in a panel of normal and tumor ovarian tissues and ovarian cancer cell lines (including the p16-insensitive RB+/p16+ ovarian cancer cell line, NIH-OVCAR-3).