Differential effects of oncogenic H- and K-ras expression on HT-29 colorectal carcinoma cell line.

The Ras oncogene is mutated in about 30% of the human tumors and its mutations are always point mutations concerning codon 12, 13 and 61. These mutations cause in the proteins a reduced GTPase activity, so that they become constitutively active. In human cells there are three main isoforms of Ras (H, K, N-ras) which can trigger alternative pathways of signal trasduction. In order to investigate the effects of expression of different oncogenic Ras isoforms in colorectal carcinoma cells (HT-29), we obtained stable clones of HT-29 cells transfected with cDNAs codifying H-RasG12V and K-Ras G12V called respectively H12 and K12 and K-RasG13D called K13, under the control of an hormone-inducible p…