Induction of apoptosis in glioma cells by molecules released from activated macrophages.
Macrophages play an important role in the regulation of malignant tumors. Although glioma contains abundance of macrophages, their role in apoptosis of glioma is not known. We stimulated macrophages with lipopolysaccharide and culture supernatants of activated macrophages were collected to treat glioma cells. The results showed that molecules released from activated macrophages significantly increased apoptosis of glioma via Fas/FasL and caspase-3 pathways. The level of soluble Fas did not appear to be involved in the mechanism responsible for apoptosis seen in this study, as its level was barely detected in both experimental and control groups. Two cytokines, TNFalpha and IFNgamma, were significantly elevated in the supernatant obtained from the activated macrophages. Considering an important role of these two molecules in the induction of apoptosis mediated by the Fas/FasL system, the present data suggested that TNFalpha and IFNgamma were the main molecules to trigger the cascade of apoptotic reactions in glioma cells. In conclusion, the present study indicates that molecules released from the activated macrophages provide significant signals to stimulate the expression of Fas/FasL and caspase-3, which function to induce apoptosis in glioma cells.
Department of Surgery, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin. gchen@cuhk.edu.hk
George G
GG
Chen
Ying S
YS
Chu
Ernest C W
EC
Chak
Billy C S
BC
Leung
Wai S
WS
Poon
D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D001932:Brain Neoplasms; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002450:Cell Communication / Q000276:immunology; D053222:Fas Ligand Protein; D005910:Glioma; D007371:Interferon-gamma / Q000378:metabolism; D008264:Macrophages / Q000378:metabolism*; D008562:Membrane Glycoproteins / Q000096:biosynthesis; D051381:Rats; D011916:Rats, Inbred F344; D014407:Tumor Cells, Cultured / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D019014:fas Receptor / Q000096:biosynthesis
D053222:Fas Ligand Protein; C505662:Faslg protein, rat; D008562:Membrane Glycoproteins; D014409:Tumor Necrosis Factor-alpha; D019014:fas Receptor; D007371:Interferon-gamma; C505410:Casp3 protein, rat; D053148:Caspase 3; D020169:Caspases