In vitro malignant progression of cells derived from Abelson murine leukaemia virus-induced thymic lymphomas.
Cell lines derived from A-MuLV induced thymic lymphomas in BALB/c and C57BL/6 mice were analysed for their in vivo and in vitro potential of growth. Despite their immunogenicity, cell lines of BALB/c origin readily grew in syngeneic recipients. On the contrary, all cell lines of C57BL/6 origin failed to grow in immunocompetent hosts even though they were able to form tumours in immunosuppressed syngeneic mice. Among C57BL/6 lymphoma cells progression toward a more malignant phenotype was observed in TB6-3 cells, and in their derived clones, after several in vitro passages. This event was accompanied by the in vitro loss of requirement for exogenous growth factor(s) when tumorigenic TB6-3 cells were plated at high density. Moreover, culture medium from fully malignant TB-3 cells was mitogenic for mature T-lymphoma cells suggesting the involvement of an autocrine mechanism in the control of cell proliferation. Apparently, the viral oncogene (v-abl) is not directly involved in malignant progression since no differences between nontumorigenic and tumorigenic cells could be detected in A-MuLV integration patterns, v-abl specific mRNA expression, and P160gag-abl production.
Saggioro
D
D
Institute of Oncology, University of Padova, Italy.
Zamarchi
R
R
D'Andrea
E
E
Chieco-Bianchi
L
L
D000011:Abelson murine leukemia virus; D000818:Animals; D002460:Cell Line; D002472:Cell Transformation, Viral; D006183:H-2 Antigens / Q000276:immunology; D007376:Interleukin-2 / Q000096:biosynthesis; D008223:Lymphoma / Q000276:immunology / Q000473:pathology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology; D013953:Thymus Neoplasms / Q000276:immunology / Q000473:pathology*
D006183:H-2 Antigens; D007376:Interleukin-2