STAT1-dependent and STAT1-independent gene expression in murine immune cells following stimulation with interferon-alpha.
OBJECTIVE
The precise molecular targets of interferon-alpha (IFN-alpha) therapy of melanoma are unknown but likely involve signal transducer and activator of transcription 1 (STAT1) signal transduction within host immune effector cells. We hypothesized that microarray analysis could be utilized to identify candidate molecular targets important for mediating the anti-tumor effect of exogenously administered IFN-alpha.


METHODS
To identify the STAT1-dependent genes regulated by IFN-alpha, the gene expression profile of splenocytes from wild type (WT) and STAT1(-/-) mice was characterized.


RESULTS
This analysis identified 30 genes that required STAT1 signal transduction for optimal expression in response to IFN-alpha (p < 0.001). These genes include granzyme b (Gzmb), interferon regulatory factor 7 (Irf7), Fas death domain-associated protein (Daxx), and lymphocyte antigen 6 complex, locus C (Ly6c). The expression of 20 genes was found to be suppressed in the presence of STAT1 including chemokine ligand 2 (Ccl2), Ccl5, and Ccl7. Nineteen genes were significantly upregulated in murine splenocytes following treatment with IFN-alpha regardless of the presence of STAT1 including CD86, lymphocyte antigen 6 complex, locus A (Ly6a), and Tap binding protein (Tapbp). The expression of representative IFN-responsive genes was confirmed at the transcriptional level by Real Time PCR.


CONCLUSIONS
This report is the first to demonstrate that STAT1-mediated signal transduction plays a major role in the transcriptional response of murine immune cells to IFNalpha.
Zimmerer
Jason M
JM
Integrated Biological Sciences Graduate Program, The Ohio State University Comprehensive Cancer Center, Columbus, OH 43210, USA.
Lesinski
Gregory B
GB
Radmacher
Michael D
MD
Ruppert
Amy
A
Carson
William E
WE
D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D005786:Gene Expression Regulation; D016898:Interferon-alpha / Q000494:pharmacology*; D051379:Mice; D008810:Mice, Inbred C57BL; D046228:Microarray Analysis; D050794:STAT1 Transcription Factor / Q000235:genetics* / Q000378:metabolism*; D015398:Signal Transduction / Q000276:immunology; D013154:Spleen / Q000166:cytology* / Q000187:drug effects* / Q000276:immunology; D015854:Up-Regulation
D000970:Antineoplastic Agents; D016898:Interferon-alpha; D050794:STAT1 Transcription Factor