Gene Expression Changes Associated with Sustained p16 Expression in Hepatocellular Carcinoma Cells

ABSTRACT

BACKGROUND: The normal functions of the cell cycle inhibitor p16INK4a are frequently inactivated in many human cancers. Over 80% of hepatocellular carcinoma (HCC) cases lack a functional p16/Rb pathway. p16/Rb pathway, as well as p53 pathway, is considered as one of key components of tumor suppression. METHODS: To study the roles of p16INK4a in HCC, a stable cell line expressing exogenous p16 was generated from SNU-449 hepatocellular carcinoma cells lacking endogenous p16, and suppression subtractive hybridization (SSH) was performed in parallel with the control cells. RESULTS: 1) SSH identifies fibronectin (FN1), crystallin alphaB (CRYAB), Rac1, WASP, RhoGEF, and CCT3 as differentially-expressed genes. 2) Among the selected genes, the up- regulation of FN1 and CRYAB was confirmed by Northern blot, RT-PCR and by proteomic methods. CONCLUSION: These genes are likely to be associated with the induction of stress fiber and stabilization of cytoskeleton. Further studies are required to clarify the possible role of p16 in the signal transduction pathway.