NUSAP1, a novel stemness-related protein, promotes early recurrence of hepatocellular carcinoma.

Early recurrence (within 2 years after resection) is the primary cause of poor outcomes among hepatocellular carcinoma (HCC) patients, and liver cancer stem cells are the main contributors to postsurgical HCC recurrence. Nucleolar and spindle-associated protein 1 (NUSAP1) has been reported to be involved in tumor progression. We investigated the function and clinical value of NUSAP1 in early recurrence of HCC. Data from public datasets and our cohort were used to assess the association between NUSAP1 expression and early HCC recurrence. Gain- and loss-of-function experiments were carried out in vivo and in vitro. The predictive effect of NUSAP1 on early HCC recurrence was further evaluated by a validation cohort. We found that elevated NUSAP1 expression in HCC specimens was correlated with poor outcome, especially in cases with postoperative early recurrence. Functional studies indicated that NUSAP1 significantly promotes HCC progression. A postsurgical recurrence murine model further revealed that upregulated NUSAP1 dramatically increased the likelihood of HCC early recurrence. RNA sequencing data revealed that the gene sets of cancer stemness and the signal transducer and activator of transcription 3 (STAT3) pathway were enriched by NUSAP1 overexpression. Mechanistically, NUSAP1 enhanced cancer stemness through stimulating STAT3 nuclear translocation and activation through receptor of activated protein C kinase 1 (RACK1). In a validation cohort with 112 HCC patients, NUSAP1 effectively predicted HCC early recurrence. Our results indicated that NUSAP1 promotes early recurrence of HCC by sustaining cancer stemness and could serve as a valuable predictive indicator for postsurgical intervention in HCC patients.

Inflammatory microenvironment of fibrotic liver promotes hepatocellular carcinoma growth, metastasis and sorafenib resistance through STAT3 activation.

The pro-inflammatory and pro-fibrotic liver microenvironment facilitates hepatocarcinogenesis. However, the effects and mechanisms by which the hepatic fibroinflammatory microenvironment modulates intrahepatic hepatocellular carcinoma (HCC) progression and its response to systematic therapy remain largely unexplored. We established a syngeneic orthotopic HCC mouse model with a series of persistent liver injury induced by CCl4 gavage, which mimic the dynamic effect of hepatic pathology microenvironment on intrahepatic HCC growth and metastasis. Non-invasive bioluminescence imaging was applied to follow tumour progression over time. The effect of the liver microenvironment modulated by hepatic injury on sorafenib resistance was investigated in vivo and in vitro. We found that the persistent liver injury facilitated HCC growth and metastasis, which was positively correlated with the degree of liver inflammation rather than the extent of liver fibrosis. The inflammatory cytokines in liver tissue were clearly increased after liver injury. The two indicated cytokines, tumour necrosis factor-α (TNF-α) and interleukin-6 (IL-6), both promoted intrahepatic HCC progression via STAT3 activation. In addition, the hepatic inflammatory microenvironment contributed to sorafenib resistance through the anti-apoptotic protein mediated by STAT3, and STAT3 inhibitor S3I-201 significantly improved sorafenib efficacy impaired by liver inflammation. Clinically, the increased inflammation of liver tissues was accompanied with the up-regulated STAT3 activation in HCC. Above all, we concluded that the hepatic inflammatory microenvironment promotes intrahepatic HCC growth, metastasis and sorafenib resistance through activation of STAT3.

RCE1 deficiency enhances invasion via the promotion of epithelial-mesenchymal transition and predicts poor prognosis in hepatocellular carcinoma.

Ras converting CAAX endopeptidase 1 (RCE1) is an integral membrane protease involved in cell proliferation, differentiation, and carcinogenesis. RCE1 plays opposite roles in different tumor types; however, the actual biological function of RCE1 in hepatocellular carcinoma (HCC) is unknown. Here, we aim to investigate the prognostic value and molecular function of RCE1 in HCC. We performed immunohistochemistry in 20 normal human liver, 216 HCC, and 216 adjacent non-tumorous tissues and analyzed the expression change and clinical value of RCE1. Additionally, in vitro and in vivo studies were performed to investigate the role of RCE1 in regulating HCC proliferation, invasion, and metastasis. We found decreased RCE1 expression in HCC tissues. Moreover, the RCE1 expression level was negatively correlated with pathological parameters characteristic of early recurrence (P < 0.044) and the serum alpha-fetoprotein (AFP) level (P < 0.018). Survival analysis indicated that reduced RCE1 expression was a predictor of poor outcomes in patients with HCC. Functional studies showed that the knockdown of RCE1 promoted proliferation, migration, and invasion of HCC cells, while RCE1 overexpression suppressed these effects. In vivo studies further confirmed that the stable knockdown of RCE1 resulted in more rapid tumor growth and an increased number of lung metastatic nodules. Mechanistically, we found that RCE1 deficiency induced epithelial-mesenchymal transition (EMT) via activation of the P38 signaling pathway. Collectively, these results indicate that RCE1 deficiency enhances invasion via promoting epithelial-mesenchymal transition. The downregulation of RCE1 in HCC tissues predicts an unsatisfactory prognosis for patients with HCC.

Intrahepatic cholangiocarcinoma induced M2-polarized tumor-associated macrophages facilitate tumor growth and invasiveness.

BACKGROUND: M2-polarized tumor-associated macrophages (M2-TAMs) have been shown to correlate with the progression of various cancers, including intrahepatic cholangiocarcinoma (ICC). However, the interactions and mechanism between M2 macrophages and ICC are not completely clear. We aimed to clarify whether M2 macrophages promote the malignancy of ICC and its mechanism. METHODS: Two progressive murine models of ICC were used to evaluate the alterations in different macrophage populations and phenotypes. Furthermore, we assessed M2 macrophage infiltration in 48 human ICC and 15 normal liver samples. The protumor functions and the underlying molecular mechanisms of M2 macrophages in ICC were investigated in an in vitro coculture system. RESULTS: We found that the number of M2 macrophages was significantly higher in ICC tissues than in normal bile ducts in the two murine models. M2 macrophage infiltration was highly increased in peritumoral compared with intratumoral regions and normal liver (p < 0.01). ICC cells induced macrophages to differentiate into the M2-TAM phenotype, and coculture with these M2 macrophages promoted ICC cell proliferation, invasion and epithelial-mesenchymal transition (EMT) in vitro. Mechanistically, M2-TAM-derived IL-10 promoted the malignant properties of ICC cells through STAT3 signaling. Furthermore, blockade of IL-10/STAT3 signaling partly rescued the effects of M2 macrophages on ICC. CONCLUSION: Our results indicated that M2-polarized macrophages induced by ICC promote tumor growth and invasiveness through IL-10/STAT3-induced EMT and might be a potential therapeutic target for ICC.

EFTUD2 maintains the survival of tumor cells and promotes hepatocellular carcinoma progression via the activation of STAT3.

Elongation factor Tu GTP binding domain containing 2 (EFTUD2), a spliceosomal GTPase, plays a pivotal role in multiple organ development and innate immune. It has been reported that EFTUD2 is a new host factor with activity against HCV infection. However, the role of EFTUD2 in solid tumors, including hepatocellular carcinoma (HCC), remains unexplored. In this study, we investigated the molecular function of EFTUD2 in HCC. Data from The Cancer Genome Atlas (TCGA) indicated an upregulation of EFTUD2 in HCC tissues compared to that in nontumor liver tissues. Immunohistochemical analysis performed on two independent HCC cohorts confirmed the upregulation of EFTUD2 in HCC tissues and further suggested that a high level of EFTUD2 expression predicted shorter overall and recurrence-free survival in HCC patients. Functional studies suggested that siRNA interference with EFTUD2 expression significantly suppressed cell viability, blocked cell cycle progression, facilitated tumor cell apoptosis, and inhibited metastasis, while the enhancement of EFTUD2 expression promoted the proliferation and migration of HCC cells both in vitro and in vivo. Surprisingly, we also found that the stable knockdown of EFTUD2 expression via lentivirus infection was lethal for HCC cells. This finding suggested that EFTUD2 was essential for maintaining the survival of HCC cells. Mechanistically, RNA sequencing and gene set enrichment analysis (GSEA) suggested that the gene sets of epithelial-mesenchymal transition (EMT) and the JAK/STAT3 pathway were enriched in EFTUD2-overexpressing cells. Further verification indicated that EFTUD2-overexpressing cells exhibited an EMT-like phenotype and had enhanced STAT3 activation, while the STAT3 inhibitor S3I-201 partially blocked these pro-malignant effects of EFTUD2 overexpression. In summary, we report EFTUD2 as a novel oncogene that helps to maintain the survival of HCC cells and promotes HCC progression through the activation of STAT3. The high level of expression of EFTUD2 in HCC tissues indicates shorter overall and recurrence-free survival in HCC patients.

Pyruvate Kinase M2 Tetramerization Protects against Hepatic Stellate Cell Activation and Liver Fibrosis.

Liver fibrosis is an increasing health problem worldwide, for which no effective antifibrosis drugs are available. Although the involvement of aerobic glycolysis in hepatic stellate cell (HSC) activation has been reported, the role of pyruvate kinase M2 (PKM2) in liver fibrogenesis still remains unknown. We examined PKM2 expression and location in liver tissues and primary hepatic cells. The in vitro and in vivo effects of a PKM2 antagonist (shikonin) and its allosteric agent (TEPP-46) on liver fibrosis were investigated in HSCs and liver fibrosis mouse model. Chromatin immunoprecipitation sequencing and immunoprecipitation were performed to identify the relevant molecular mechanisms. PKM2 expression was significantly up-regulated in both mouse and human fibrotic livers compared with normal livers, and mainly detected in activated, rather than quiescent, HSCs. PKM2 knockdown markedly inhibited the activation and proliferation of HSCs in vitro. Interestingly, the PKM2 dimer, rather than the tetramer, induced HSC activation. PKM2 tetramerization induced by TEPP-46 effectively inhibited HSC activation, reduced aerobic glycolysis, and decreased MYC and CCND1 expression via regulating histone H3K9 acetylation in activated HSCs. TEPP-46 and shikonin dramatically attenuated liver fibrosis in vivo. Our findings demonstrate a nonmetabolic role of PKM2 in liver fibrosis. PKM2 tetramerization or suppression could prevent HSC activation and protects against liver fibrosis.

Tyrosine kinase SYK is a potential therapeutic target for liver fibrosis.

Spleen tyrosine kinase (SYK) plays a critical role in immune cell signaling pathways and has been reported as a biomarker for human hepatocellular carcinoma (HCC). We sought to investigate the mechanism by which SYK promotes liver fibrosis and to evaluate SYK as a therapeutic target for liver fibrosis. We evaluated the cellular localization of SYK and the association between SYK expression and liver fibrogenesis in normal, hepatitis B virus (HBV)-infected, hepatitis C virus (HCV)-infected and non-alcoholic steatohepatitis (NASH) liver tissue (n=36, 127, 22 and 30, respectively). A polymerase chain reaction (PCR) array was used to detect the changes in transcription factor (TF) expression in hepatic stellate cells (HSCs) with SYK knockdown. The effects of SYK antagonism on liver fibrogenesis were studied in LX-2 cells, TWNT-4 cells, primary human HSCs, and three progressive fibrosis/cirrhosis animal models, including a CCL4 mouse model, and diethylnitrosamine (DEN) and bile duct ligation (BDL) rat models. We found that SYK protein in HSCs and hepatocytes correlated positively with liver fibrosis stage in human liver tissue. HBV or HCV infection significantly increased SYK and cytokine expression in hepatocytes. Increasing cytokine production further induced SYK expression and fibrosis-related gene transcription in HSCs. Up-regulated SYK in HSCs promoted HSC activation by increasing the expression of specific TFs related to activation of HSCs. SYK antagonism effectively suppressed liver fibrosis via inhibition of HSC activation, and decreased obstructive jaundice and reduced HCC development in animal models. Conclusion: SYK promotes liver fibrosis via activation of HSCs and is an attractive potential therapeutic target for liver fibrosis and prevention of HCC development. (Hepatology 2018).

MCM6 promotes metastasis of hepatocellular carcinoma via MEK/ERK pathway and serves as a novel serum biomarker for early recurrence.

BACKGROUND: The high incidence of recurrence and metastasis of hepatocellular carcinoma (HCC) necessitate the discovery of new predictive biomarkers of invasion and prognosis. Minichromosome maintenance complex component 6 (MCM6), which has been reported to up-regulate in multiple malignancies, was considered to be a novel diagnoses biomarker in HCC. However, its functional contributions and prognostic value remain unclear. METHODS: The expression of MCM6 was analyzed in 70 HCC tissues and 5 HCC cell lines by immunohistochemistry and real-time RT-PCR. The roles of MCM6 in HCC cell proliferation, migration and invasion were explored by CCK8, Wound healing and Transwell assays, respectively. Western blotting and Immunofluorescence staining were conducted to detect the protein expressions of ERK signaling pathway and EMT-related markers. To verify the above findings in vivo, we established subcutaneous xenograft tumor and orthotopic xenograft tumor models in nude mice. Finally, Enzyme-linked immunosorbent assay was used to evaluate the serum MCM6 level. RESULTS: MCM6 was significantly up-regulated in HCC tissues. Increased MCM6 expression was associated with aggressive clinicopathological features and worse prognosis in HCC patients. These results were consistent with our analyses of The Cancer Genome Atlas database (TCGA). Furthermore, knockdown of MCM6 significantly decreased proliferative and migratory/invasive capability of HCC cells in vitro, as well as decreased tumor volume, weight and the number of pulmonary metastases in vivo. Mechanistic analyses indicated that MCM6 promoted EMT and activated MEK/ERK signaling. More importantly, serum MCM6 levels in HCC patients were significantly higher than those in cirrhosis and healthy controls (P < 0.0001), and allowed distinguishing early recurrence with high accuracy (AUC = 0.773). CONCLUSIONS: Our findings indicate that MCM6 predicts poor prognosis and promotes metastasis in HCC. Postoperative serum MCM6 level could be valuable to detect preclinical early recurrence, indicative of a need for more careful surveillance and aggressive therapeutic intervention.