SOCS5 is a member of the suppressor of cytokine signaling (SOCS) protein family with important yet incompletely understood biological functions in cancer. In hepatocellular carcinoma (HCC), controversial tumor-promoting and tumor-suppressive roles of SOCS5 have been reported. Our study aims to unravel novel functions of SOCS5 in HCC, especially that affecting metastasis. We examined the expression levels of SOCS5 in HCC using publicly available datasets, and in our patient cohort, using quantitative real-time PCR, western blotting, and immunohistochemistry. The association of SOCS5 expression with clinical pathological data of HCC patients was examined and that with the mTOR pathway was predicted. We further studied the effects of SOCS5 on PI3K/Akt/mTOR activity; HCC cell autophagy, migration, and invasion; and HCC cell metastasis in vitro and in vivo. We observed that SOCS5 was significantly overexpressed in HCC tissues, compared to adjacent non-tumor liver tissues, in both the public datasets and in our patient cohort. SOCS5 overexpression was significantly and inversely correlated with HCC patient prognosis. Moreover, SOCS5 overexpression promoted HCC cell migration and invasion in vitro by inactivating PI3K/Akt/mTOR-mediated autophagy. Conversely, SOCS5 inhibition suppressed HCC cell migration and invasion in vitro by activating PI3K/Akt/mTOR-mediated autophagy. Dual inhibition of SOCS5 and mTOR further enhanced autophagy and the subsequent anti-metastatic effects on HCC cells. In vivo, stable knockdown of SOCS5 reduced HCC cell metastasis. Overall, our study revealed a novel metastasis-promoting function of SOCS5 in HCC, acting via the PI3K/Akt/mTOR-mediated autophagy pathway. Combined inhibition of SOCS5 and mTOR may be a potential therapeutic approach to inhibit HCC metastasis and prolong patient survival.

AIM: To confirm the anti-invasion and anti-migration effects of down-regulation of Notch1 combined with interleukin (IL)-24 in hepatocellular carcinoma (HCC) cells. METHODS: γ-secretase inhibitors (GSIs) were used to down-regulate Notch1. HepG2 and SMMC7721 cells were seeded in 96-well plates and treated with GSI-I or/and IL-24 for 48 h. Cell viability was measured by MTT assay. The cellular and nuclear morphology was observed under a fluorescence microscope. To further verify the apoptotic phenotype, cell cultures were also analyzed by flow cytometry with Annexin V-FITC/propidium iodide staining. The expression of Notch1, SNAIL1, SNAIL2, E-cadherin, IL-24, XIAP and VEGF was detected by Western blot. The invasion and migration capacities of HCC cells were detected by wound healing assays. Notch1 and Snail were down-regulated by RNA interference, and the target proteins were analyzed by Western blot. To investigate the mechanism of apoptosis, we analyzed HepG2 cells treated with siNotch1 or siCON plus IL-24 or not for 48 h by caspase-3/7 activity luminescent assay. RESULTS: GSI-I at a dose of 2.5 μmol/L for 24 h caused a reduction in cell viability of about 38% in HepG2 cells. The addition of 50 ng/mL IL-24 in combination with 1 or 2.5 μmol/L GSI-I reduced cell viability of about 30% and 15%, respectively. Treatment with IL-24 alone did not induce any cytotoxic effect. In SMMC7721 cells with the addition of IL-24 to GSI-I (2.5 μmol/L), the reduction of cell viability was only about 25%. Following GSI-I/IL-24 combined treatment for 6 h, the apoptotic rate of HepG2 cells was 47.2%, while no significant effect was observed in cells treated with the compounds employed separately. Decreased expression of Notch1 and its associated proteins SNAIL1 and SNAIL2 was detected in HepG2 cells. Increased E-cadherin protein expression was noted in the presence of IL-24 and GSI-I. Furthermore, the increased GSI-I and IL-24 in HepG2 cell was associated with downregulation of MMP-2, XIAP and VEGF. In the absence of treatment, HepG2 cells could migrate into the scratched space in 24 h. With IL-24 or GSI-I treatment, the wound was still open after 24 h. And the distance of the wound closure strongly correlated with the concentrations of IL-24 and GSI-I. Treatment of Notch-1 silenced HepG2 cells with 50 ng/mL IL-24 alone for 48 h induced cytotoxic effects very similar to those observed in non-silenced cells treated with GSI-I/IL-24 combination. Caspase-3/7 activity was increased in the presence of siNotch1 plus IL-24 treatment. CONCLUSION: Down-regulation of Notch1 by GSI-I or siRNA combined with IL-24 can sensitize apoptosis and decrease the invasion and migration capabilities of HepG2 cells.

Abnormal lipid metabolism promotes hepatocellular carcinoma (HCC) progression, which engenders therapeutic difficulties owing to unclear mechanisms of the phenomenon. We precisely described a special steatotic HCC subtype with HBV-related cirrhosis and probed its drivers. Hematoxylin-eosin (HE) staining of 245 HCC samples revealed a special HCC subtype (41 cases) characterized by HBV-related cirrhosis and intratumoral steatosis without fatty liver background, defined as steatotic HCC with HBV-related cirrhosis (SBC-HCC). SBC-HCC exhibits a larger tumor volume and worse prognosis than non-SBC-HCC. Screening for driver genes promoting fatty acid (FA) biosynthesis in the Gao’s HBV-related cirrhosis HCC cases and GSE121248’ HBV-related HCC cases revealed that high expression of SOCS5 predicts increased FA synthesis and that SOCS5 is upregulated in SBC-HCC. Through proteomics, metabolomics, and both in vivo and in vitro experiments, we demonstrated that SOCS5 induces lipid accumulation to promote HCC metastasis. Mechanistically, through co-IP and GST-pulldown experiments, we found that the SOCS5-SH2 domain, especially the amino acids Y413 and D443, act as critical binding sites for the RBMX-RRM domain. SOCS5-RBMX costimulates the promoter of SREBP1, inducing de novo lipogenesis, while mutations in the SH2 domain, Y413, and D443 reverse this effect. These findings precisely identified SBC-HCC as a special steatotic HCC subtype and highlighted a new mechanism by which SOCS5 promotes SBC-HCC metastasis.

Background: In hepatocellular carcinoma (HCC), inflammatory factors play an important role, but their effects on the prognosis of patients with HCC are still not very clear. Methods: Immunohistochemical staining was used to detect the expression of tumor necrosis factor-alpha (TNF-α) and nuclear factor-kappa B (NF-κB) in tumour tissues of Barcelona Clinic Liver Cancer-0-B stage (BCLC-0-B) patients with HCC. The relationship between TNF-α and NF-κB expression and clinicopathological features was analysed by χ2 test. Kaplan-Meier analysis and the log-rank test were used to compare the prognoses of TNF-α and NF-κB high and low-expression groups among HCC patients. The Cox proportional hazard model was used to analyse HCC prognosis by univariate and multivariate analysis. Results: Patients with HCC had significantly longer survival times in the TNF-α/NF-κB high-coexpression group (P<0.05). High expression of TNF-α and NF-κB is an independent prognostic factor predicting postoperative survival and recurrence in patients with HCC (P<0.05). Conclusions: High expression of TNF-α and NF-κB in the HCC microenvironment can predict survival, and patients with high expression have longer survival times and slowing the recurrence time than those in the low-expression group.

Following publication of this article [1], it was realized that an error was made in typesetting which resulted in a change in the ordering of the last two authors. The correct ordering of the authors for the paper is as follows:Mao Zhang, Shihai Liu, Mei-Sze Chua, Haoran Li, Dingan Luo, Sheng Wang, Shun Zhang, Chuandong Sun (*) & Bing Han (*)[(*) indicates corresponding author]An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Purpose: To explore the effect of miR-449a inhibits migration and invasion by targeting Notch1 and regulating epithelial–mesenchymal transition (EMT) in hepatocellular carcinoma (HCC), and further study on the molecular mechanism. Patients and methods: The expression of miR-449a and Notch1 in HCC cells and tissues was detected by qRT-PCR. The HCC cell line HCCLM3 and SMMC-7721 were transfected with miR-449a. The invasion and migration of HCC cell lines were detected by transwell assay and wound healing assay. The Notch pathway and EMT related protein were detected with Western Blotting. The specific binding site of mir-449a on notch1 gene was detected by luciferase assay. Results: We found the expression of miR-449a was related to short-term recurrence of hepatocellular carcinoma after hepatectomy and acted as independent risk factors of DFS and OS. The expression of miR-449a decreased in tumor tissues and HCC cell lines, but the expression of Notch1 increased. The overexpressed miR-449a promoted the invasiveness in vitro by regulating EMT via Notch pathway. Mechanically, miR-449a inhibited the translation of Notch1 protein by binding to 3ʹ UTR of its mRNA directly. Conclusion: miR-449a is short-term recurrence-related miRNA and inhibits the invasion and metastasis ability of HCC cells by regulating EMT via Notch pathway. miR-449a may be a new effective therapeutic target for HCC.