Serum withdrawal induces apoptotic cell death in Ki-ras transformed but not in normal differentiated thyroid cells.
Thyroid cells transformed by the Kirsten-ras oncogene become tumorigenic in syngeneic animals. Their growth is no longer dependent on TSH but becomes dependent on serum. Combining morphological and biochemical evidence, we show that serum withdrawal induces apoptotic cell death in Kirsten and Harvey-ras transformed thyroid cell. On the other hand, neither serum nor TSH withdrawal induce apoptosis in differentiated FRTL-5 cells. The induction of apoptosis by serum withdrawal is rapid and not triggered at a specific phase of the cell cycle. We suggest that induction of apoptosis following growth factor deprivation is an additional important characteristic, besides TSH-independence for growth and dedifferentiation, of the thyroid transformed phenotype.
di Jeso
B
B
Centro di Endocrinologia ed Oncologia Sperimentale del Consiglio Nazionale delle Ricerche, Università Federico II, Medical School, Napoli, Italia.
Ulianich
L
L
Racioppi
L
L
D'Armiento
F
F
Feliciello
A
A
Pacifico
F
F
Consiglio
E
E
Formisano
S
S
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001769:Blood; D002454:Cell Differentiation; D002455:Cell Division / Q000187:drug effects; D002471:Cell Transformation, Neoplastic; D016895:Culture Media, Serum-Free; D004247:DNA / Q000032:analysis; D005434:Flow Cytometry; D011905:Genes, ras; D007700:Kinetics; D007708:Kirsten murine sarcoma virus / Q000235:genetics; D051381:Rats; D013961:Thyroid Gland; D013972:Thyrotropin / Q000494:pharmacology*; D013997:Time Factors
D016895:Culture Media, Serum-Free; D013972:Thyrotropin; D004247:DNA