Hep G2 간암세포주에서 Retinoic Acid 가 p53 단백 , Ki - 67 및 PCNA / Cyclin 발현에 미치는 효과

Ol4ctlves: Retinoic acid(RA), known to have antiproliferative and differentiation-inducing effects on cancer cells, was examined to evaluate its potential as a chemotherapeutic agent for hepatocellular carcinoma. Methods: We examined the level of expressions of the p53 protein, the Ki-67 antigen, and the proliferation cell nuclear antigen(PCNA) in cultured Hep G2 hepatocelluar carcinoma cells before and after RA treatment. The mutant p53 is thought to be involved in development of human cancers, and the expressions of the Ki-67 and the PCNA are used to evaluate tumor cell kinetics. Results: The expression of p53 protein was significantly inhibited in Hep G2 cells by treatment with 10-5 M RA, from 61.1±1.3 to 53.3±0.8% in G0/G1 phase fraction(p=0.001), as detected by immunocytochemical staining using the monoclonal antibody PAb 1801 which recognizes both the wild type and the mutant p53 protein. The significant decrement of expression was also demonstrated using the monoclonal antibody PAb 240 which binds only the mutant p53 protein, from 55.6±0.4% to 50.8±1.2% in G0/G1 phase fraction(p=0.019) and 18.2±0.6% to 8.9±1.3%(p=0.0003) in S phase fraction Also RA treatment increased Go unstained fraction from 0.6±0.1% to 5.9±0.7% and decreased Ki-67 antigen expression significantly from 4.0±1.4% to 10.2±1.5% in S phase, PCNA expression was also dropped by RA treatment in every cell cycle fraction, from 57.0±0.7% to 47.3±1.9% in G0/G1 from 15.2±0.7 % to 10.6±0.6% in S, from 20.5±0.85% to 13.6±0.7% in G2/M phase. Conclusion: RA appeared to have anticancer effect through the inhibition of p53 protein expression, Ki-67 and PCNA expression in Hep G2 cells in similar but not coincident proliferating mode. In addition cell cycle anaysis suggested that RA induced an arrest of G0 progression to G1 and S phase.