Fig. 3.

IR-B expression is enhanced in a non-transformed human intestinal epithelial cell line (HIECs) and Caco-2 cells with the capacity to spontaneously differentiate versus tumorigenic colorectal cancer (CRC) cell lines. RT-PCR using primers spanning exon 11 evaluated ratio of IR-B∶IR-A mRNA expression in subconfluent, actively dividing non-transformed HIEC, Caco-2 CRC cells capable of spontaneous differentiation, and HT-29, HCT116, and SW480 CRC lines. Note the low expression of IR-B in HT-29, HCT116, and SW480 in representative blot and after quantification of band intensity. Histogram represents mean ± s.e.m. (n≧2).