Growth Suppression of Human Ovarian Cancer Cells by the Introduction of the p16 Gene Via a Recombinant Adenovirus In Vitro

Kim, T W; Wolf, Judith K; Shin, J I; Kim, Y W; Kim, J W; Kim, J H; Namkoong, S E; Kim, S J; Kim, S P

Abstract

OBJECTIVE
The cell cycle regulatory p16 protein (the product of the CDKN2A gene also called p16INK4A, CDK4I, and MTS-1) causes cell cycle arrest at the G1 checkpoint by inhibiting activity of cyclin D and CDK4/6 complexes. The purpose of this study is to assess the growth suppressive effect by introduction of the p16 gene into two ovarian cancer cell lines via a recombinant adenoviral vector (Ad5CMV-p16).
METHODS
The cell lines used for this study are: SKOV3 (deletion of the p16 gene) and OVCA 420 (no mutation along the coding region of the p16 gene by SSCP). To assess the transduction efficiency, cells were with an adenovirus containing Escherichia coli -galactosidase gene (Ad5CMV-LacZ) at different multiplicity of infection (MOI) from 0-500; then stained for X-gal. To assess the effects on cell growth, cells were infected with Ad5CMV-p16 then counted every other day up to 7 days. Controls were mock-infected cells and cells infected with Ad5CMV-LacZ. Western blot and cell cycle analysis were done to assess expression of the p16 gene.
RESULTS
The transduction efficiencies were 80% with an MOI of 100 in SKOV3 cells and 75% with an MOI of 250 in OVCA 420 cells. Growth of the Ad5CMV-p16 infected cells was suppressed over 75% by cell count in both cell lines with significant morphological changes of cells. The p16 protein was detected in both cell lines by Western blot analysis 24 hours after introduction of the p16 gene and expressed for at least 6 days. A clear shift to G1 phase was found in Ad5CMV-p16 infected cells of both cell lines by cell cycle analysis.
CONCLUSION
These results suggest that Ad5CMV-p16 may be further studied as a potential therapeutic agent for ovarian cancer since introduction of the p16 gene into two ovarian cancer cell lines attenuates their growth.