Ehrlich ascites tumor cells expressing anti-sense glutaminase mRNA lose their capacity to evade the mouse immune system.
Glutaminase (EC 3.5.1.2) is a key enzyme in rapidly proliferating cells. Using anti-sense technology, an Ehrlich ascites tumor cell line (0.28AS-2) with reduced glutaminase activity has been obtained. We investigated the in vivo growth characteristics of the 0.28AS-2 cells. When injected i.p. into normal Swiss albino mice, the 0.28AS-2 cells were unable to grow. On the contrary, when injected into nude mice, they developed into solid tumors. Mice inoculated with 0.28AS-2 cells kept immunologic memory and rejected a second inoculation with parental Ehrlich ascites tumor cells. Expression of both polymorphic epithelial mucin-1 (MUC-1) and the enzyme N-acetyl-alpha-D-galactosaminidase, proteins implicated in host immune system escape, were markedly diminished in 0.28AS-2 cells. Study of the immune system response in mice inoculated with 0.28AS-2 cells revealed an increase in splenic CD18 cells and the presence of a large number of activated F4/80+ macrophages in the ascites cavity. These features, not observed in mice inoculated with parental Ehrlich ascites tumor cells, indicate that a distinctive, strong immune response occurred in animals inoculated with 0.28AS-2 cells. Our results suggest that inhibition of glutaminase expression using anti-sense technology induces phenotypic changes in Ehrlich ascites tumor cells that allow the development of an effective anti-tumor immune response, which makes the cells unable to develop in vivo tumors.
Segura
J A
JA
Departamento de Biología Molecular y Bioquímica, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain. jsegura@uma.es
Ruiz-Bellido
M A
MA
Arenas
M
M
Lobo
C
C
Márquez
J
J
Alonso
F J
FJ
D000818:Animals; D002286:Carcinoma, Ehrlich Tumor / Q000201:enzymology* / Q000276:immunology / Q000473:pathology; D005260:Female; D005972:Glutaminase / Q000037:antagonists & inhibitors / Q000276:immunology / Q000378:metabolism*; D006596:Hexosaminidases / Q000276:immunology / Q000378:metabolism*; D007111:Immunity, Cellular; D007156:Immunologic Memory; D051379:Mice; D008819:Mice, Nude; D018396:Mucin-1 / Q000378:metabolism; D009363:Neoplasm Proteins / Q000276:immunology / Q000378:metabolism*; D016372:RNA, Antisense / Q000378:metabolism*; D016212:Transforming Growth Factor beta / Q000378:metabolism; D014407:Tumor Cells, Cultured; D048809:alpha-N-Acetylgalactosaminidase
D018396:Mucin-1; D009363:Neoplasm Proteins; D016372:RNA, Antisense; D016212:Transforming Growth Factor beta; D006596:Hexosaminidases; D048809:alpha-N-Acetylgalactosaminidase; D005972:Glutaminase