C-raf-1 proto-oncogene expression relates to radiosensitivity rather than radioresistance.
The transfection of several oncogenes, particularly c-raf-1, into mammalian in vitro cell lines has been reported to be associated with increased radioresistance. We have thus investigated (by scanning photodensitometry of western blots) the phenotypic expression of the c-raf-1, c-myc and c-ras protein products in 19 human in vitro cell lines, whose intrinsic cellular sensitivity to 4 MeV photon irradiation has also been determined. High levels of c-raf-1 proto-oncogene product expression did not correlate with increased cellular radioresistance, but rather showed a significant correlation with intrinsic cellular radiosensitivity to photon irradiation for alpha (r = 0.664, P = 0.002), and SF2 (r = -0.655, P = 0.002). There was no significant correlation for the ras family, c-myc or actin. These results conflict with those of previous studies in which transfection of the activated forms of the c-raf-1 oncogene were associated with increased radioresistance, and suggest the possibility that the full length proto-oncogene may influence cellular radiosensitivity in a different manner from that of the activated oncogene.
Warenius
H M
HM
Dept of Medicine, University of Liverpool, U.K.
Browning
P G
PG
Britten
R A
RA
Peacock
J A
JA
Rapp
U R
UR
D015153:Blotting, Western; D002470:Cell Survival / Q000528:radiation effects; D015870:Gene Expression; D006801:Humans; D017346:Protein Serine-Threonine Kinases / Q000096:biosynthesis* / Q000235:genetics*; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis*; D016271:Proto-Oncogene Proteins c-myc / Q000096:biosynthesis; D019908:Proto-Oncogene Proteins c-raf; D016283:Proto-Oncogene Proteins p21(ras) / Q000096:biosynthesis; D011836:Radiation Tolerance / Q000235:genetics*; D014407:Tumor Cells, Cultured / Q000378:metabolism / Q000528:radiation effects*
C000715470:MAS1 protein, human; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins; D016271:Proto-Oncogene Proteins c-myc; D017346:Protein Serine-Threonine Kinases; D019908:Proto-Oncogene Proteins c-raf; C501009:HRAS protein, human; D016283:Proto-Oncogene Proteins p21(ras)