Oncostatin M: From Intracellular Signaling to Therapeutic Targets in Liver Cancer

Simple Summary Pro-inflammatory cytokines play a key role in innate- and adaptive-immunity-mediated liver carcinogenesis. Among these, oncostatin M (OSM) critically contributes to physiological and pathological processes, including extracellular matrix remodeling, hematopoiesis, differentiation, inflammatory response, proliferation, acquisition of cancer stem cell markers, drug resistance, and metastatic phenotype. Here, we review the current knowledge on the role of OSM in liver cancers, focusing on recent progress in the understanding of the molecular mechanisms of IL-6-type cytokine signaling cascades. Primary liver cancers represent the third-most-common cause of cancer-related mortality worldwide, with an incidence of 80-90% for hepatocellular carcinoma (HCC) and 10-15% for cholangiocarcinoma (CCA), and an increasing morbidity and mortality rate. Although HCC and CCA originate from independent cell populations (hepatocytes and biliary epithelial cells, respectively), they develop in chronically inflamed livers. Evidence obtained in the last decade has revealed a role for cytokines of the IL-6 family in the development of primary liver cancers. These cytokines operate through the receptor subunit gp130 and the downstream Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling pathways. Oncostatin M (OSM), a member of the IL-6 family, plays a significant role in inflammation, autoimmunity, and cancer, including liver tumors. Although, in recent years, therapeutic approaches for the treatment of HCC and CCA have been implemented, limited treatment options with marginal clinical benefits are available. We discuss how OSM-related pathways can be selectively inhibited and therapeutically exploited for the treatment of liver malignancies.