Abstract #475: Human RIF1 encodes an anti-apoptotic factor required for DNA repair

Human RIF1 (Rap1 interacting protein 1) is involved in cellular responses to DNA damage by forming nuclear foci and playing a role in the S-phase checkpoint. We here showed that inhibition of RIF1 expression by siRNA led to a defective repair of DNA double strand breaks by homologous recombination, and sensitized cancer cells to camptothecin or staurosporine treatment. RIF1 underwent caspase-dependent cleavage upon apoptosis. We further found that RIF1 was highly expressed in human breast tumors, and its expression status was positively correlated with differentiation degrees of invasive ductal carcinoma of the breast. Our results suggest that RIF1 encodes an anti-apoptotic factor required for DNA repair and is a potential target for cancer treatment.

Citation Information: In: Proc Am Assoc Cancer Res; 2009 Apr 18-22; Denver, CO. Philadelphia (PA): AACR; 2009. Abstract nr 475.