Comparison of human mammary epithelial cells immortalized by simian virus 40 T-Antigen or by the telomerase catalytic subunit.
We directly compared two methods of immortalizing human mammary epithelial cells (HMECs). Cells were transfected with an expression plasmid either for hTERT, the catalytic subunit of telomerase, or for the simian virus 40 (SV40) early region genes. Under standard culture conditions, HMECs were not immortalized by hTERT unless they had spontaneously ceased expression of the p16(INK4a) tumor suppressor gene. Untransfected HMECs had low levels of telomerase expression, and immortalization by both methods was associated with an increase in telomerase activity and prevention of telomere shortening. SV40-induced immortalization was accompanied by aberrant differentiation, loss of DNA damage response, karyotypic instability and, in some cases, tumorigenicity. hTERT-immortalized cells had fewer karyotypic changes, but had intact DNA damage responses, and features of normal differentiation. Although SV40-immortalized cells are useful for studies of carcinogenesis, hTERT-immortalized cells retain more properties of normal cells.
Toouli
Christian D
CD
Children's Medical Research Institute, 214 Hawkesbury Road, Westmead 2145, Australia.
Huschtscha
Lily I
LI
Neumann
Axel A
AA
Noble
Jane R
JR
Colgin
Lorel M
LM
Hukku
Bharati
B
Reddel
Roger R
RR
D000328:Adult; D000782:Aneuploidy; D000952:Antigens, Polyomavirus Transforming / Q000235:genetics / Q000502:physiology*; D001940:Breast / Q000166:cytology*; D020134:Catalytic Domain; D002454:Cell Differentiation; D002461:Cell Line, Transformed; D002470:Cell Survival; D002471:Cell Transformation, Neoplastic; D002472:Cell Transformation, Viral; D002869:Chromosome Aberrations; D002877:Chromosomes, Human / Q000648:ultrastructure; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000172:deficiency / Q000502:physiology; D004247:DNA / Q000187:drug effects; D004249:DNA Damage; D003609:Dactinomycin / Q000494:pharmacology; D004847:Epithelial Cells / Q000201:enzymology / Q000473:pathology / Q000821:virology; D005260:Female; D019942:Genes, p16; D006801:Humans; D007364:Intercalating Agents / Q000494:pharmacology; D007621:Karyotyping; D021122:Protein Subunits; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000502:physiology; D013539:Simian virus 40 / Q000235:genetics / Q000502:physiology*; D019098:Telomerase / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D016615:Telomere / Q000648:ultrastructure; D014162:Transfection
D000952:Antigens, Polyomavirus Transforming; D019941:Cyclin-Dependent Kinase Inhibitor p16; D007364:Intercalating Agents; D021122:Protein Subunits; D011993:Recombinant Fusion Proteins; D003609:Dactinomycin; D004247:DNA; D019098:Telomerase