The IL-6/sIL-6R treatment of a malignant melanoma cell line enhances susceptibility to TNF-alpha-induced apoptosis.
Melanoma is an intractable tumor that has shown very impressive and promising response to local administration of high dose recombinant TNF-alpha in combination with IFN-gamma in clinical studies. In this study, we investigated the effect of IL-6/sIL-6R on TNF-alpha-resistant B16/F10.9 melanoma cells. A low dose of TNF-alpha or IL-6/sIL-6R had minimal affect on the cell growth. However, the highly active fusion protein of sIL-6R and IL-6 (IL6RIL6), covalently linked by a flexible peptide, sensitized TNF-alpha-resistant F10.9 melanoma cells to TNF-alpha-induced apoptosis. Stimulation of the cells with IL6RIL6 plus TNF-alpha resulted in both the activation of caspase-3 and the reduction of bcl-2 expression. Flow cytometry analysis showed that IL6RIL6-upregulated TNF-R55 and TNF-R75 expression, suggesting an increase in TNF-alpha responsiveness by IL6RIL6 resulting from the induction of TNF receptors. Moreover, exposure of F10.9 cells to neutralizing antibody to TNF-R55 significantly inhibited IL6RIL6/TNF-alpha-induced cytotoxicity. These results suggest that the IL6/sIL6R/gp130 system, which sensitizes TNF-alpha-resistant melanoma cells to TNF-alpha-induced apoptosis, may provide a new target for immunotherapy.
Wagley
Yadav
Y
Department of Anatomy, College of Medicine, Chosun University, 375 Seosuk-Dong, Dong-Gu, Gwangju, Republic of Korea.
Yoo
Yung-Choon
YC
Seo
Han Geuk
HG
Rhee
Man Hee
MH
Kim
Tae-Hyoung
TH
Kang
Keon Wook
KW
Nah
Seung-Yeol
SY
Oh
Jae-Wook
JW
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D050822:Cytokine Receptor gp130 / Q000502:physiology; D004357:Drug Synergism; D015850:Interleukin-6 / Q000627:therapeutic use*; D008545:Melanoma / Q000188:drug therapy*; D051379:Mice; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis; D019947:Receptors, Interleukin-6 / Q000627:therapeutic use*; D047889:Receptors, Tumor Necrosis Factor, Type II / Q000096:biosynthesis / Q000276:immunology; D011993:Recombinant Fusion Proteins / Q000627:therapeutic use*; D012995:Solubility; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D015854:Up-Regulation
D015850:Interleukin-6; D019253:Proto-Oncogene Proteins c-bcl-2; D019947:Receptors, Interleukin-6; D047889:Receptors, Tumor Necrosis Factor, Type II; D011993:Recombinant Fusion Proteins; D014409:Tumor Necrosis Factor-alpha; C104543:interleukin 6-interleukin 6 receptor fusion protein, recombinant; D050822:Cytokine Receptor gp130