Tumorigenicity of SEWA murine cells correlates with degree of c-myc amplification.
Previous studies have shown that cells of the SEWA mouse tumor contain amplified copies of the proto-oncogene c-myc in the aberrant chromosomal structures of double minutes (DMs), homogeneously staining regions (HSRs) and C-bandless chromosomes (CMs). DMs, and to a lesser degree CMs, tend to disappear from the cells grown in vitro and again reappear after transfer back in vivo, as if DNA amplification confers a growth advantage upon the tumor cells. We have now isolated five in vitro clones that exhibit different degrees of c-myc amplification. When we inoculated cells of the different clones into compatible hosts, we found that there was a positive correlation between degree of c-myc amplification, level of c-myc RNA, and tumorigenicity. Our results lend further support to the idea that gene amplification contributes to the higher malignant phenotype, and to progression of tumors.
Martinsson
T
T
Department of Genetics, Gothenburg University, Sweden.
Ståhl
F
F
Pollwein
P
P
Wenzel
A
A
Levan
A
A
Schwab
M
M
Levan
G
G
D000818:Animals; D002460:Cell Line; D002471:Cell Transformation, Neoplastic; D002871:Chromosome Banding; D002999:Clone Cells; D005784:Gene Amplification; D008677:Metaphase; D051379:Mice; D008815:Mice, Inbred Strains; D011505:Protein-Tyrosine Kinases / Q000235:genetics; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D016271:Proto-Oncogene Proteins c-myc; D011519:Proto-Oncogenes; D012334:RNA, Neoplasm / Q000235:genetics / Q000302:isolation & purification
D011518:Proto-Oncogene Proteins; D016271:Proto-Oncogene Proteins c-myc; D012334:RNA, Neoplasm; D011505:Protein-Tyrosine Kinases