Premium
Relationship between chemically induced ha‐ ras mutation and transformation of BALB/c 3T3 cells: Evidence for chemical‐specific activation and cell type—specific recruitment of oncogene in transformation
Author(s) -
Nakazawa Hisayoshi,
Aguelon AnneMarie,
Yamasaki Hiroshi
Publication year - 1990
Publication title -
molecular carcinogenesis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.254
H-Index - 97
eISSN - 1098-2744
pISSN - 0899-1987
DOI - 10.1002/mc.2940030407
Subject(s) - dmba , biology , carcinogenesis , mutation , mutation frequency , microbiology and biotechnology , 3t3 cells , transformation (genetics) , carcinogen , cell , oncogene , cell culture , cancer research , cell cycle , transfection , genetics , gene
BALB/c 3T3 cells were exposed to 7, 12‐dimethylbenz[ a ]anthracene (DMBA) and resultant transformed foci were analyzed for the presence of A 182 → T mutation at codon 61 of Ha‐ ras (a mutation found in many DMBA‐induced animal tumors). None of the 30 independently cloned transformed cell lines contained such a mutation. In order to see whether DMBA is able to induce this mutation in BALB/c 3T3 cells, we developed a method sensitive enough to detect this specific mutation at the frequency of 10 –6 . Employing this assay, we found time‐and dose‐dependent induction by DMBA of Ha‐ ras A 182 → T mutation in BALB/c 3Tc cells; for example, 2 wk after exposure to 100 μg/mL DMBA, 1.4 in 1 × 10 4 cells contained this specific mutation. On the other hand, other agents that also induce BALB/c 3T3 cell transformation, such as 3‐methylcholanthrene (MCA), 12‐ O ‐tetradecanoylphorbol‐13‐acetate (TPA), N ‐methyl‐ N '‐nitro‐ N ‐nitrosoguanidine (MNNG), or ultraviolet light, did not induce the mutation at detectable frequency (< 10 –6 ). These results suggest that DMBA efficiently induces Ha‐ ras mutation in BALB/c 3T3 cells but that this mutation is not recruited in the process of cell transformation. A hypothesis of carcinogen‐specific mutation of Ha‐ ras gene and its tissue (cell type)‐specific recruitment in carcinogenesis is proposed.