Characteristics of an infinite life span diploid human fibroblast cell strain and a near-diploid strain arising from a clone of cells expressing a transfected v-myc oncogene

Exp Cell Res. 1991 Nov;197(1):125-36. doi: 10.1016/0014-4827(91)90489-h.

Abstract

Diploid human fibroblasts were transfected with a plasmid carrying a v-myc oncogene linked to the neo gene or with a vector control carrying a neo gene. Drug-resistant clones were isolated and subcultured as needed. All populations went into crisis and eventually senesced. But while they were senescing, viable-appearing clones were noted among the progeny of a transfected population that expressed the v-myc oncogene. After several months, these cells began replicating more rapidly. Karyotype analysis indicated that they were clonally derived since all of them had 45 chromosomes, including 2 marker chromosomes. This cell strain was designated MSU-1.1. Similar analysis showed that cells from an earlier passage were diploid. These cells were designated MSU-1.0. Both strains have undergone more than 200 population doublings since their siblings senesced, without any change in chromosome complement. Both strains express the v-myc protein and have the same integration site for the transfected v-myc and neo genes. The MSU-1.0 cells cannot grow without exogenously added growth factors. The MSU-1.1 cells grow moderately well under the same conditions and grow to a higher saturation density than MSU-1.0 cells. Since the chance of human cells acquiring an infinite life span in culture is very rare, the data suggest that MSU-1.1 cells are derived from MSU-1.0 cells. The expression of v-myc is probably required for acquisition of an infinite life span, since this phenotype did not develop in populations not expressing this oncogene. However, expression of v-myc is clearly not sufficient, since all of the progeny of the clone that gave rise to the MSU-1.0 cells expressed this oncogene, but the vast majority of them senesced.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Blotting, Southern
  • Cell Death
  • Cell Division
  • Cell Line, Transformed*
  • Chickens
  • Chromosome Banding
  • Clone Cells
  • Culture Media, Serum-Free
  • Diploidy
  • Fibroblasts / cytology*
  • Genes, myc*
  • Growth Substances / pharmacology
  • Humans
  • Karyotyping
  • Male
  • Mice
  • Neoplasm Transplantation
  • Time Factors
  • Transfection

Substances

  • Culture Media, Serum-Free
  • Growth Substances