ARF triggers cell G1 arrest by a P53 independent ERK pathway.

In this study, in order to investigate the p53-independent function of p14ARF, we established p14ARF-inducible clones in the p53-deficient HCT cell line using the doxycycline-inducible expression system. A strong cell growth inhibition and G1/S arrest were observed after doxycycline induction in p53-/-HCT cells, and the cells also exhibited an obvious decrease of DNA synthesis. We further examined if the MEK/ERK pathway is involved in the G1 arrest induced by p14ARF in p53-/-HCT cells. The results indicate that ERK1/2 and p21 were activated upon p14ARF induction. Totally, the functional roles of ERK and p21 for ARF in p53-independent tumor suppression were demonstrated.