Hepatitis B virus PreS1 facilitates hepatocellular carcinoma development by promoting appearance and self-renewal of liver cancer stem cells.

Hepatitis B virus (HBV) is a major etiologic agent of hepatocellular carcinoma (HCC). However, the molecular mechanism by which HBV infection contributes to HCC development is not fully understood. Here, we initially showed that HBV stimulates the production of cancer stem cells (CSCs)-related markers (CD133, CD117 and CD90) and CSCs-related genes (Klf4, Sox2, Nanog, c-Myc and Oct4) and facilitates the self-renewal of CSCs in human hepatoma cells. Cellular and clinical studies revealed that HBV facilitates hepatoma cell growth and migration, enhances white blood cell (WBC) production in the sera of patients, stimulates CD133 and CD117 expression in HCC tissues, and promotes the CSCs generation of human hepatoma cells and clinical cancer tissues. Detailed studies revealed that PreS1 protein of HBV is required for HBV-mediated CSCs generation. PreS1 activates CD133, CD117 and CD90 expression in normal hepatocyte derived cell line (L02) and human hepatoma cell line (HepG2 and Huh-7); facilitates L02 cells migration, growth and sphere formation; and finally enhances the abilities of L02 cells and HepG2 cells to induce tumorigeneses in nude mice. Thus, PreS1 acts as a new oncoprotein to play a key role in the appearance and self-renewal of CSCs during HCC development.

Liu Z ，Dai X ，Wang T ，Zhang C ，Zhang W ，Zhang W ，Zhang Q ，Wu K ，Liu F ，Liu Y ，Wu J ... -  《-》

Hepatitis B virus mRNAs functionally sequester let-7a and enhance hepatocellular carcinoma.

Hepatitis B virus (HBV) infection induces hepatocarcinogenesis and malignant progression, yet global effects of the redundant viral mRNAs produced during infection are unexplored. Here, microRNA (miRNA) target prediction and whole genome expression analysis revealed that HBV pre-C/C mRNA leads to upregulation of multiple let-7a targeted genes. A let-7a complementary region from nt 86 to 108 in the HBV genome was then identified in HBV pre-C/C, pre-S, and S mRNAs. The let-7a sequestration effect by HBV mRNAs was observed under transfection and virus infection, which is dependent on the let-7a response sequence. Moreover, we found reduced AGO2 binding, as well as functional mRNA and protein de-repression of let-7a targets (e.g., c-myc, K-RAS, and CCR7), upon viral mRNA expression. Let-7a levels in the liver were significantly decreased in hepatocellular carcinoma (HCC) patients with HBV infection and were negatively correlated with intrahepatic pre-S2 mRNA levels. Finally, both in vitro and in vivo studies demonstrated that let-7a inhibition by HBV mRNAs resulted in enhanced HCC cell colony formation and tumor growth, providing evidence of the oncogenic potential of HBV mRNAs.

Deng M ，Hou J ，Hu J ，Wang S ，Chen M ，Chen L ，Ju Y ，Li C ，Meng S ... -  《-》

HBx drives alpha fetoprotein expression to promote initiation of liver cancer stem cells through activating PI3K/AKT signal pathway.

Hepatitis B virus (HBV)-X protein (HBx) plays critical role in inducing the malignant transformation of liver cells. Alpha fetoprotein (AFP) expression is closely related to hepatocarcinogenesis. We report that Oct4, Klf4, Sox2 and c-myc expression positively associated with AFP(+)/HBV(+) hepatocellular carcinoma(HCC) tissues, and the expression of the stemness markers CD44, CD133 and EpCAM was significantly higher in AFP(+)/HBV(+) HCC tissues compared to normal liver tissues or AFP (-)/HBV(-) HCC tissues. AFP expression turned on prior to expression of Oct4, Klf4, Sox2 and c-myc, and the stemness markers CD44, CD133 and EpCAM in the normal human liver L-02 cell line or CHL cell lines upon transfection with MCV-HBx vectors. Stem-like cells generated more tumour colonies compared to primary cells, and xenografts induced tumourigenesis in nude mice. Expression of reprogramming-related proteins was significantly enhanced in HLE cells while transfected with pcDNA3.1-afp vectors. The specific PI3K inhibitor Ly294002 inhibited the effects of pcDNA3.1-afp vectors. AFP-siRNA vectors were able to inhibit tumour colony formation and reprogramming-related gene expression. Altogether, HBx stimulates AFP expression to induce natural reprogramming of liver cells, and AFP plays a critical role in promoting the initiation of HCC progenitor/stem cells. AFP may be a potential novel biotarget for combating HBV-induced hepatocarcinogenesis.

Zhu M ，Li W ，Lu Y ，Dong X ，Lin B ，Chen Y ，Zhang X ，Guo J ，Li M ... -  《-》

The collagen triple helix repeat containing 1 facilitates hepatitis B virus-associated hepatocellular carcinoma progression by regulating multiple cellular factors and signal cascades.

Hepatitis B virus (HBV) infection is one of the major causes of acute and chronic liver diseases, fulminant hepatitis, cirrhosis, and hepatocellular carcinoma (HCC). HCC accounts for more than 85% of primary liver cancers and is the seventh most common cancer and the third leading cause of cancer-related deaths. However, the mechanism by which HBV induces HCC is largely unknown. Collagen triple helixes repeat containing 1 (CTHRC1) is a secreted protein and has characteristics of a circulating hormone with potentially broad implications for cell metabolism and physiology. CTHRC1 is associated with human cancers, but its effect on HCC is unknown. Here, we revealed that CTHRC1 expression is highly correlated with HCC progression in HBV-infected patients, and demonstrated that HBV stimulates CTHRC1 expression by activating nuclear factor-kappa B (NF-κB) and cAMP response element binding protein (CREB), through extracellular signal-regulated kinase/c-Jun N-terminal kinase (ERK/c-JNK) pathway. In addition, CTHRC1 activates hypoxia-inducible factor 1α (HIF-1α) and vascular endothelial growth factor (VEGF) through regulating phosphoinosmde-3-kinase/protein kinase B/mammalian target of rapamycin (PI-3K/AKT/mTOR) pathway. More interestingly, CTHRC1 enhances colony formation, migration, and invasion of hepatoma cells by regulating p53 and stimulating matrix metalloproteinase-9 (MMP-9) expression. In addition, knock-down of CTHRC1 results in the repression of HBV-associated carcinogenesis in nude mice. Thus, we revealed a novel mechanism by which HBV facilitates HCC development through activating the oncoprotein CTHRC1, which in turn enhances HBV-related HCC progression by stimulates colony formation, migration, and invasion of hepatoma cells through regulating multiple cellular factors and signal cascades.

Zhang R ，Cao Y ，Bai L ，Zhu C ，Li R ，He H ，Liu Y ，Wu K ，Liu F ，Wu J ... -  《-》

Up-regulation of human cervical cancer proto-oncogene contributes to hepatitis B virus-induced malignant transformation of hepatocyte by down-regulating E-cadherin.

Li J ，Dai X ，Zhang H ，Zhang W ，Sun S ，Gao T ，Kou Z ，Yu H ，Guo Y ，Du L ，Jiang S ，Zhang J ，Zhou Y ... -  《Oncotarget》