Oncogene expression in murine splenic T cells and in murine T-cell neoplasms.
The differential expression of a series of proto-oncogenes has been examined in a group of cultured murine T-cell lymphomas that were induced following virus inoculation into, or X irradiation of, C57BL/6 mice. Two classes of T lymphoma cell lines were studied: growth factor-dependent (autocrine) cells, and growth factor-independent T lymphoma cells. Cell lines that were established from X-irradiation-induced T lymphomas were growth factor dependent, whereas T lymphoma lines grown from virus-induced tumors were generally growth factor independent. Of 18 cellular proto-oncogenes studied, five (c-myc, c-myb, c-abl, c-rasHa, c-rasKi) were consistently expressed in all cell lines tested. Thirteen other proto-oncogenes (c-mos, c-sis, c-rel, c-yes, c-fes3, c-fes4, c-fos, c-fms, c-src, c-erbA, c-erbB, int-1, Pim-1) were not expressed in any of the T lymphoma cells tested. Concanavalin A-stimulated spleen cells, representative of replicating T cells, expressed c-myc, c-abl, and Pim-1, suggesting that the products of these proto-oncogenes are involved in T-cell proliferation. The results indicate no qualitative differences (albeit some quantitative differences) in proto-oncogene expression between the growth factor-dependent and growth factor-independent cells. This suggests that expression of the five proto-oncogenes is in itself not sufficient to induce the progression of the growth factor-dependent cells to their fully growth factor-independent counterparts. Changes in the regulation of one or more of the five active proto-oncogenes, i.e., from an inducible to a constitutive state, and/or additional changes in the expression of other cellular genes may be required to induce the transformation of neoplastic T cells from growth factor dependence to growth factor independence.
M I
MI
Mally
M
M
Vogt
S E
SE
Swift
M
M
Haas
D000818:Animals; D008213:Lymphocyte Activation; D008223:Lymphoma / Q000235:genetics / Q000382:microbiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D009381:Neoplasms, Radiation-Induced / Q000235:genetics; D009693:Nucleic Acid Hybridization; D011519:Proto-Oncogenes; D012313:RNA / Q000302:isolation & purification; D013045:Species Specificity; D013154:Spleen / Q000276:immunology; D013601:T-Lymphocytes / Q000382:microbiology*; D014158:Transcription, Genetic
D012313:RNA