RETINOBLASTOMA GENE PRODUCT-ASSOCIATED PROTEINS IN HUMAN COLON-CANCER CELL-LINES

The expression of cellular proteins that associate with the human retinoblastoma (RB1) gene protein was examined in three colorectal carcinoma cell lines (SW480, SW403, DiFi) by immunoprecipitation analysis, using the mouse monoclonal antibody (RB-Mab-1) directed against the RB1 gene product (RB). The potential of RN-Mab-1 to detect RB-associated proteins by immunoprecipitation analysis was confirmed using three control cell lines (WI-38, J82, T24) known to express RB and/or RB-associated proteins. In all colon cancer cell lines tested, multiple RB-associated protein (RAP) bands were found with molecular weights of 30-50 kDa. Because involvement of the RB1 gene in colorectal tumorignesis appears to differ from its role in other cancer types (wherein RB1 is lost or inactivated), it will be important to characterize the role of RAPs in RB growth regulatory mechanism of colonic epithelial cells. © 1993 Academic Press, Inc.