IL-12 pretreatments enhance IFN-alpha-induced Janus kinase-STAT signaling and potentiate the antitumor effects of IFN-alpha in a murine model of malignant melanoma.
IFN-alpha 2b (IFN-alpha) has been used to treat patients with metastatic malignant melanoma and patients rendered disease-free via surgery but at high risk for recurrence. We hypothesized that IL-12 pretreatments would result in endogenous IFN-gamma production, and that this, in turn, would up-regulate levels of Janus kinase-STAT signaling intermediates and lead to increased expression of genes regulated by IFN-alpha. Treatment of PBMCs with IL-12 stimulated a significant and dose-dependent production of IFN-gamma. Pretreatment of PBMCs and tumor cells with IFN-gamma-containing supernatants from IL-12-stimulated PBMCs led to up-regulation of STAT1, STAT2, and IFN regulatory factor 9 (IRF9) and potentiated IFN-alpha-induced STAT signaling within PBMCs and tumor cells. These effects were abrogated by neutralization of IFN-gamma in the PBMC supernatants with an anti-IFN-gamma Ab. Pretreatment of HT144 melanoma cells and PBMCs with IFN-gamma or IFN-gamma-containing supernatants enhanced the actions of IFN-alpha at the transcriptional level, as measured by real-time RT PCR analysis of the IFN-stimulated gene 15. Experiments in wild-type C57BL/6 and IFN-gamma receptor knockout (B6.129S7-Ifngr(tm1Agt)) mice demonstrated that a regimen of IL-12 pretreatment, followed by IFN-alpha, could cure mice of i.p. B16F1 melanoma tumors (p < 0.007), whereas mice treated with either agent alone or PBS succumbed to fatal tumor burden. However, this treatment regimen did not significantly prolong the survival of IFN-gamma-deficient (B6.129S7-Ifng(tm1Ts)) mice compared with mice treated with IFN-alpha alone. These results suggest that the response to IFN-alpha immunotherapy can be significantly enhanced by IL-12 pretreatment, and this effect is dependent upon endogenous IFN-gamma production and its actions on melanoma cells.
Lesinski
Gregory B
GB
Department of Human Cancer Genetics, Ohio State University, Columbus, OH 43210, USA.
Badgwell
Brian
B
Zimmerer
Jason
J
Crespin
Tim
T
Hu
Yan
Y
Abood
Gerard
G
Carson
William E
WE
D000818:Animals; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology*; D045744:Cell Line, Tumor; D004268:DNA-Binding Proteins; D004357:Drug Synergism; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D016898:Interferon-alpha / Q000096:biosynthesis / Q000494:pharmacology*; D018664:Interleukin-12 / Q000494:pharmacology*; D053613:Janus Kinase 1; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000276:immunology; D008546:Melanoma, Experimental / Q000188:drug therapy*; D051379:Mice; D011505:Protein-Tyrosine Kinases; D050794:STAT1 Transcription Factor; D015398:Signal Transduction; D015534:Trans-Activators
D004268:DNA-Binding Proteins; D016898:Interferon-alpha; D050794:STAT1 Transcription Factor; C494079:STAT1 protein, human; C494080:Stat1 protein, mouse; D015534:Trans-Activators; D018664:Interleukin-12; D011505:Protein-Tyrosine Kinases; C507904:JAK1 protein, human; C507905:Jak1 protein, mouse; D053613:Janus Kinase 1