Growth factor-induced proliferative responses of human and DMH-induced rat colorectal tumour cell lines

The proliferative response of three human and three 1,2-dimethylhydrazine (DMH)-induced rat colon tumour cell lines to mouse epidermal growth factor (mEGF) and human urogastrone was examined in two in vitro assays (3H-thymidine uptake in liquid microculture and clonogenicity in semi-solid medium). In the 3H-thymidine uptake assay, one of three rat and one of three human colon tumour cell lines, i.e., r237 and LIM1215, were stimulated by mEGF. In the clonogenic assay, mEGF stimulated the one clonogenic rat tumour cell line r113, which did not respond in the 3H-thymidine uptake assay, and the human tumour cell line LIM1215. Urogastrone stimulated LIM1215 in both assay systems. The significance of these in vitro patterns of response to growth stimulatory factors is discussed.