DIRECT TUMORIGENIC CONVERSION OF HUMAN GALLBLADDER CARCINOMA-CELLS BYV-SRC BUT NOT BY ACTIVATED C-H-RAS ONCOGENE

The roles of activated ras and src oncogene products in the acquisitio n of fully neoplastic phenotype by human gallbladder adenocarcinoma ce lls were investigated by co-transfecting nontumorigenic HAG-I human ga llbladder carcinoma cells with the pSV2neo plasmid and a plasmid carry ing either activated c-H-ras or v-src oncogene. G418-resistant clones were isolated and assessed for the acquisition of anchorage-independen t growth potential. Neither the 10 established clones transfected with pSV2neo alone nor the 17 clones transfected with activated c-H-ras, i ncluding 4 clones expressing the mutated p21(H-ras) protein, could for m colonies in soft: agar. By contrast, out of 10 clones transfected wi th v-src, 2 formed colonies in soft agar and produced tumors in athymi c nude mice, the resulting progressive neoplasms being poorly differen tiated adenocarcinomas. These tumorigenic clones were shown to have v- src DNA and mRNA levels with p60(v-src) protein, But there were no sig nificant chromosomal alterations following tumorigenic conversion. Mor eover, herbimycin A, a selective src-kinase inhibitor, markedly reduce d clonogenic growth of these cells in soft agar rather than monolayer growth, suggesting that anchorage-independent growth of the v-src-tran sformed HAG-I cells might be driven directly by p60(v-src) kinase acti vity. Taken together, our data suggest that the fully neoplastic conve rsion of NAG-I cells depends on src-related tyrosine-kinase activity, but not solely on the function mediated by activated ras, thus providi ng evidence of an src-related signaling pathway for the acquisition of tumorigenic potential by human gallbladder adenocarcinoma cells. (C) 1995 Wiley-Liss, Inc.