C-HA-RAS ONCOGENE TRANSFECTION DOES NOT AFFECT NK CELL SENSITIVITY OFHUMAN COLORECTAL-CARCINOMA CELL-LINES

Background, Materials and Methods: To investigate whether a c-Ha-ras o ncogene, pointmutated in codon 12, modulates NK sensitivity of human c olorectal tumor cells, this oncogene was introduced in two colorectal carcinoma cell lines, i.e. CaCo2 and SW480. Results: Although transfec tion with this oncogene increased the levels of c-Hn-ras mRNA (4- to 5 -fold) and induced phenotypic and genotypic changes, respectively, in the CaCo2 and SW480 cell lines, the susceptibility to NK cell lysis wa s only marginally affected. However, CaCo2 and SW480 cell lines transf ected with a plasmic containing the wild type of the c-Ha-ras gene wer e found to be more sensitive to NK cells. Conclusions: The present stu dy suggests that the sensitivity of human colorectal carcinoma cells t o NK cell activity in vitro depends only marginally on the expression of the c-Ha-ras oncogene.