The cellular ecology of progressive neoplastic transformation: A clonal analysis
AUTOR(ES)
Chow, Ming
FONTE
The National Academy of Sciences
RESUMO
A comparison was made of the competence for neoplastic transformation in three different sublines of NIH 3T3 cells and multiple clonal derivatives of each. Over 90% of the neoplastic foci produced by an uncloned transformed (t-SA′) subline on a confluent background of nontransformed cells were of the dense, multilayered type, but about half of the t-SA′ clones produced only light foci in assays without background. This asymmetry apparently arose from the failure of the light focus formers to register on a background of nontransformed cells. Comparison was made of the capacity for confluence-mediated transformation between uncloned parental cultures and their clonal derivatives by using two nontransformed sublines, one of which was highly sensitive and the other relatively refractory to confluence-mediated transformation. Transformation was more frequent in the clones than in the uncloned parental cultures for both sublines. This was dramatically so in the refractory subline, where the uncloned culture showed no overt sign of transformation in serially repeated assays but increasing numbers of its clones exhibited progressive transformation. The reason for the greater susceptibility of the pure clones is apparently the suppression of transformation among the diverse membership that makes up the uncloned parental culture. Progressive selection toward increasing degrees of transformation in confluent cultures plays a major role in the development of dense focus formers, but direct induction by the constraint of confluence may contribute by heritably damaging cells. In view of our finding of increased susceptibility to transformation in clonal versus uncloned populations, expansion of some clones at the expense of others during the aging process would contribute to the marked increase of cancer with age.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=26742Documentos Relacionados
- Irreversibility of cellular aging and neoplastic transformation: a clonal analysis.
- Clonal dynamics of progressive neoplastic transformation
- Evidence for the progressive nature of neoplastic transformation in vitro.
- Chromatin changes in cell transformation: progressive unfolding of the higher-order structure during the evolution of rat hepatocyte nodules. A differential scanning calorimetry study.
- Yeast transformation: a model system for the study of recombination.