Activated hepatic stellate cells with senescence-associated secretory phenotype signature in steatohepatitic hepatocellular carcinoma

Abstract

Steatohepatitic hepatocellular carcinoma (HCC), a new histologic variant of HCC has been recently reported in patients with metabolic syndrome or hepatitis C virus？related cirrhosis with associated non-alcoholic fatty liver disease (NAFLD). The incidence of metabolic syndrome has rapidly increased in Asia including Korea, where hepatitis B virus (HBV) is the main etiology of HCC. However, clinicopathological features of steatohepatitic HCC in HBV patients with metabolic syndrome and its molecular pathogenesis remain unclear. Steatohepatitic HCCs (n = 21) and conventional HCCs (n = 34) were selected from non-C viral, non-alcoholic and non-autoimmune hepatitis patients, and the HBV infection was evaluated by serological test of HBsAg or HBV DNA nested PCR using liver tissue. Their difference in clinical, and molecular pathological aspects was analyzed focusing hepatic stellate cell activation and senescence-associated secretory phenotype (SASP). The expression of α-smooth muscle actin (α-SMA), p21Waf1/Cif1, γ-H2AX, IL-6, and Ki-67 were investigated by single or double immunohistochemistry or immunofluorescence. Steatohepatitic HCCs showed significantly older age, higher body mass index, higher incidence of diabetes, central obesity, hypertriglyceridemia and NAFLD compared to conventional HCCs (P <0.05 for all). Metabolic syndrome was more prevalent in steatohepatitic HCCs compared to conventional HCCs (P= 0.029), whereas the incidence of HBV infection showed no significant difference between two groups. Activated hepatic stellate cells expressing p21Waf1/Cif1, IL-6 (P <0.05 for both) and γ-H2AX (P = 0.066) were more frequently found in steatohepatitic HCCs compared to conventional HCCs. Non-tumoral liver of steatohepatitic HCCs also showed higher number of activated stellate cells expressing γ-H2AX and p21Waf1/Cif1 compared to that of conventional HCCs (P <0.05 for both). There was no significant difference of Ki-67 expressing activated hepatic stellate cells between steatohepatitic and conventional HCCs in both of tumoral and non-tumoral lesions.Therefore, steatohepatitic HCC is suggested as a distinctive variant of HCC in metabolic syndrome with or without chronic B viral hepatitis. Activated hepatic stellate cells expressing senescence-associated protein (p21Waf1/Cif1 and γ-H2AX) and SASP factor (IL-6) are considered to be important in the pathogenesis of steatohepatitic HCC.