Proteomic analysis uncovers common effects of IFN-γ and IL-27 on the HLA class I antigen presentation machinery in human cancer cells.

Andrea Petretto,Paola Vacca,Elvira Inglese,Luca Longo,Valentina Rigo,Chiara Lavarello,Marina Fabbi,Michela Croce,Grazia Carbotti,Silvano Ferrini,Stefania Martini,Maria Pia Pistillo

doi:10.18632/oncotarget.12235

Abstract

IL-27, a member of the IL-12-family of cytokines, has shown anti-tumor activity in several pre-clinical models due to anti-proliferative, anti-angiogenic and immune-enhancing effects. On the other hand, IL-27 demonstrated immune regulatory activities and inhibition of auto-immunity in mouse models. Also, we reported that IL-27, similar to IFN-γ, induces the expression of IL-18BP, IDO and PD-L1 immune regulatory molecules in human cancer cells. Here, a proteomic analysis reveals that IL-27 and IFN-γ display a broad overlap of functions on human ovarian cancer cells. Indeed, among 990 proteins modulated by either cytokine treatment in SKOV3 cells, 814 showed a concordant modulation by both cytokines, while a smaller number (176) were differentially modulated. The most up-regulated proteins were common to both IFN-γ and IL-27. In addition, functional analysis of IL-27-regulated protein networks highlighted pathways of interferon signaling and regulation, antigen presentation, protection from natural killer cell-mediated cytotoxicity, regulation of protein polyubiquitination and proteasome, aminoacid catabolism and regulation of viral protein levels.Importantly, we found that IL-27 induced HLA class I molecule expression in human cancer cells of different histotypes, including tumor cells showing very low expression. IL-27 failed only in a cancer cell line bearing a homozygous deletion in the B2M gene. Altogether, these data point out to a broad set of activities shared by IL-27 and IFN-γ, which are dependent on the common activation of the STAT1 pathway. These data add further explanation to the anti-tumor activity of IL-27 and also to its dual role in immune regulation.

Highlights

IL-27 is a heterodimeric cytokine, consisting of p28 (IL-27A) and EBV-induced gene 3 (EBI3) chains, which belongs to a cytokine family comprising IL-12, IL-23, IL-30 and IL-35 [1,2,3]
The present data indicate that IL-27 profoundly modifies the protein expression profile of human cancer cells and modulates a broad set of proteins in a similar fashion as IFN-γ
Network analysis showed that IL-27 modulates the expression of proteins involved in IFN signaling and response to IFNs, among which STAT1, IRF-1 and -9, IFIT1, 2 and 3, Guanylate Binding Protein Interferon-Inducible (GBP)-1, -2, -4 and -5

Summary

Introduction

IL-27 is a heterodimeric cytokine, consisting of p28 (IL-27A) and EBV-induced gene 3 (EBI3) chains, which belongs to a cytokine family comprising IL-12, IL-23, IL-30 and IL-35 [1,2,3]. IL-27 binds to a receptor formed by gp130 and WSX1/IL-27RA chains, which signals through the STAT1/3 pathway. It mediates pleiotropic effects on T, B and NK lymphocytes, macrophages, dendritic cells and non-hematopoietic cells, and on different types of normal and neoplastic cells [1,2,3]. IL-27 induces T-bet expression and Th1 cell differentiation [8] and supports the generation of effector CD8+ T cells expressing granzyme B [9]. It has been proposed that IL-27 enhances the survival of anti-tumor CTLs and induces a peculiar stem cell-like Tc1 effector phenotype, characterized by the expression of T-bet, Eomes, Bcl, Sca and IL-10 [10]

Methods

Results

Conclusion