PIM2 promotes hepatocellular carcinoma tumorigenesis and progression through activating NF-κB signaling pathway

Inflammatory factors and activation of oncogenes both played critical roles in the development and progression of human hepatocellular carcinoma (HCC). However, the interplay between these two has not been well studied. In this study, we found that regulated by TNFα, Pim-2 proto-oncogene, serine/threonine kinase (PIM2) was highly expressed in HCC and correlated with poor prognosis (P = 0.007) as well as tumor recurrence (P = 0.014). Functional studies showed that PIM2 could enhance abilities of cell proliferation, cell motility, angiogenesis, chemo-resistance, and in vivo tumorigenicity and HCC metastasis. Mechanistic studies revealed that PIM2 could activate NF-κB signaling pathway through upregulating phosphorylation level of RIPK2. Interestingly, TNFα treatment could induce the expression of PIM2, and overexpression of PIM2 could in turn upregulate the expression of TNFα in HCC cells. More importantly, we found the expression level of PIM2 increased with the progression of liver cirrhosis, and PIM kinase inhibitor AZD1208 treatment could effectively attenuate HCC cells' tumorigenic ability both in vitro and in vivo. Collectively, our study revealed the interaction between an inflammatory factor and a proto-oncogene that contributed to tumorigenesis and progression of HCC, and PIM kinase inhibition may serve as a therapeutic target in the treatment of HCC.