Background N6-methyladenosine (m6A) methylation, a well-known modification with new epigenetic functions, has been reported to participate in the tumorigenesis of hepatocellular carcinoma (HCC), providing novel insights into the molecular pathogenesis of this disease. However, as the key component of m6A methylation, Wilms tumor 1-associated protein (WTAP) has not been well studied in HCC. Here we investigated the biological role and underlying mechanism of WTAP in liver cancer. Methods We determined the expression of WTAP and its correlation with clinicopathological features using tissue microarrays and the Cancer Genome Atlas (TCGA) dataset. And we clarified the effects of WTAP on HCC cells using cell proliferation assay, colony formation, Edu assay and subcutaneous xenograft experiments. We then applied RNA sequencing combined with gene expression omnibus (GEO) data to screen candidate targets of WTAP. Finally, we investigated the regulatory mechanism of WTAP in HCC by m6A dot blot assay, methylated RNA immunoprecipitation (MeRIP) assay, dual luciferase reporter assay, RNA immunoprecipitation (RIP) assay and Chromatin immunoprecipitation (ChIP) assay. Results We demonstrated that WTAP was highly expressed in HCC which indicated the poor prognosis, and that WTAP expression served as an independent predictor of HCC survival. Functionally, WTAP promoted the proliferation capability and tumor growth of HCC cells in vitro and in vivo. Furthermore, ETS proto-oncogene 1 (ETS1) was identified as the downstream effector of WTAP. The m6A modification regulated by WTAP led to post-transcriptional suppression of ETS1, with the implication of Hu-Antigen R (HuR) as an RNA stabilizer. Then ETS1 was found to inhibit the progression of HCC and could rescue the phenotype induced by WTAP deficiency. Moreover, WTAP modulated the G2/M phase of HCC cells through a p21/p27-dependent pattern mediated by ETS1. Conclusion We have identified that WTAP is significantly up-regulated in HCC and promotes liver cancer development. WTAP-guided m6A modification contributes to the progression of HCC via the HuR-ETS1-p21/p27 axis. Our study is the first to report that WTAP-mediated m6A methylation has a crucial role in HCC oncogenesis, and highlights WTAP as a potential therapeutic target of HCC treatment. Electronic supplementary material The online version of this article (10.1186/s12943-019-1053-8) contains supplementary material, which is available to authorized users.

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Hepatocellular carcinoma (HCC) is a highly heterogeneous, multigene-driven malignant tumor. Long chain acyl-CoA synthetase 4 (ACSL4), an enzyme has pivotal roles in arachidonic acid (AA) metabolism. However, its function and the underlying molecular mechanisms in HCC are still not fully elucidated. Here, we identified ACSL4 as a novel marker for AFP high subtype HCC through transcriptome profiling. ACSL4 was frequently upregulated in HCC samples and associated with poor prognosis. Functionally, ACSL4 knockdown resulted in decreased cell growth, whereas ectopic ACSL4 expression facilitated tumor formation in vitro and in vivo. Mechanistically, ACSL4 stabilized the oncoprotein c-Myc through ubiquitin-proteasome system in an ERK/FBW7-dependent manner. Cell growth ability mediated by ACSL4 elevation was partly attenuated by c-Myc depletion using siRNA or its inhibitor 10058-F4. In contrast, the effects of ACSL4 silencing were partially reversed by c-Myc overexpression via FBW7 knockdown. Clinically, ACSL4 expression was positively correlated with c-Myc in HCC. In conclusion, ACSL4 is a novel marker for AFP high subtype HCC. Our data uncovered a new mechanism by which ACSL4 promotes HCC progression via c-Myc stability mediated by ERK/ FBW7/c-Myc axis and could be a valuable prognostic biomarker and a potential therapeutic target in HCC.

BackgroundHypoxia is a common feature of solid tumors, including HCC. And hypoxia has been reported to play an important role in HCC progression. However, the potential mechanism of miRNAs in hypoxia mediating HCC progression still remains unclear.MethodsThe HCC cells were cultured in the atmosphere of 1 % oxygen to induce hypoxia. The microRNA microarray was employed to search for the hypoxia-inducible miRNAs. RT-PCR, western blot and immunohistochemistry were used to detect the RNA and protein levels. HUVEC were applied to explore the angiogenesis level.ResultsWe found that miR-182 was upregulated in the hypoxia-based microarray. We then revealed that miR-182 was also significantly increased in the HCC tissues compared to the corresponding normal tissues. In vitro capilliary tube formation assays showed that the miR-182 promoted angiogenesis. RASA1 was demonstrated as the direct target of miR-182. In addition, the suppression of RASA1 phenocopied the pro-angiogenesis effects of miR-182. Besides, RASA1 was also decreased in the hypoxia HCC cells while the inhibition of miR-182 partially restored the level of RASA1.ConclusionsOur data showed that hypoxia regulated the expression of miR-182 and RASA1 to promote HCC angiogenesis.Electronic supplementary materialThe online version of this article (doi:10.1186/s13046-015-0182-1) contains supplementary material, which is available to authorized users.

The genome-wide clustered regularly interspaced short palindromic repeats (CRISPR) screen is a powerful tool used to identify therapeutic targets that can be harnessed for cancer treatment. This study aimed to assess the efficacy of genome-wide CRISPR screening to identify druggable genes associated with sorafenib-treated hepatocellular carcinoma (HCC). A genome-scale CRISPR knockout (GeCKO v2) library containing 123,411 single guide RNAs (sgRNAs) was used to identify loss-of-function mutations conferring sorafenib resistance upon HCC cells. Resistance gene screens identified SGOL1 as an indicator of prognosis of patients treated with sorafenib. Of the 19,050 genes tested, the knockout screen identified inhibition of SGOL1 expression as the most-effective genetic suppressor of sorafenib activity. Analysis of the survival of 210 patients with HCC after hepatic resection revealed that high SGOL1 expression shortened overall survival (P = 0.021). Further, matched pairs analysis of the TCGA database revealed that SGOL1 is differentially expressed. When we used a lentivirus Cas9 vector to determine the effect of targeting SGOL1 with a specific sgRNA in HCC cells, we found that SGOL1 expression was efficiently inhibited and that loss of SGOL1 was associated with sorafenib resistance. Further, loss of SGOL1 from HCC cell decreased the cytotoxicity of sorafenib in vivo. We conclude that the CRISPR screen is a powerful tool for therapeutic target analysis of sorafenib treatment and that SGOL1 serves as a druggable target for HCC treated with sorafenib and an indicator of prognosis.

It has been reported that long non-coding RNA PANDA was disregulated in varieties types of tumor, but its expression level and biological role in hepatocellular carcinoma (HCC) remains contradictory. We detected PANDA expression in two independent cohorts (48 HCC patients following liver transplantation and 84 HCC patients following liver resection), and found that PANDA was down-regulated in HCC. Thereafter we explored its function in cancer biology by inversing its low expression. Surprisingly, overexpression of PANDA promoted HCC proliferation and carcinogenesis in vitro and in vivo. Mechanistically, PANDA repressed transcriptional activity of senescence associated inflammatory factor IL8, which leaded to inhibition of cellular senescence. Therefore, our research help to better understand the complex role of PANDA in HCC, and suggest more thoughtful strategies should be applied before it can be treated as a potential therapeutic target.

Background Myb-binding protein 1A (Mybbp1a) is a nucleolar protein that can regulate rRNA metabolism, the stress response and carcinogenesis. However, the function of Mybbp1a in the progression of hepatocellular carcinoma (HCC) is unclear. We aimed to determine the role of Mybbp1a in HCC and the underlying mechanism. Methods We investigated the function of Mybbp1a in HCC cell models and the xenograft mouse model. The relationship between Mybbp1a and IGFBP5 was found through expression profile chip. The molecular mechanism of Mybbp1a regulating IGFBP5 was proved through CO-IP, CHIP, Bisulfite Sequencing and Pyrosequencing. Findings In this study, we observed that Mybbp1a was overexpressed in HCC tissues and associated with the poor prognosis of HCC patients. Suppression of Mybbp1a led to a reduction in the proliferation and migration ability of HCC cells through inhibiting the IGF1/AKT signaling pathway. Further study found that Mybbp1a could form a complex with DNMT1 and induce aberrant hyper-methylation of CpG islands of IGFBP5, which inhibits secretion of IGFBP5 and then activates IGF1/AKT signaling pathway. Interpretation These findings extend our understanding of the function of Mybbp1a in the progression of HCC. The newly identified Mybbp1a may provide a novel biomarker for developing potential therapeutic targets of HCC. Fund Science Technology Department of Zhejiang Province (No. 2015C03034), National Health and Family Planning Commission of China (No. 2016138643), Innovative Research Groups of National Natural Science Foundation of China (No. 81721091), Major program of National Natural Science Foundation of China (No. 91542205).

Homeobox B7 (HOXB7) protein is reported to be aberrantly expressed in a variety of cancers and to play an important role in multiple cellular processes. However, the specific mechanism by which HOXB7 promotes the malignant progression of intrahepatic cholangiocarcinoma (ICC) remains unclear. Therefore, we used quantitative real-time polymerase chain reaction (PCR) to detect the expression level of HOXB7 in 38 paired ICC tissue samples. Additionally, to assess correlation between HOXB7 and ICC prognosis, we performed immunohistochemistry (IHC) using 122 ICC tissues to detect HOXB7 expression. Cell Counting Kit-8 (CCK-8) and colony formation assays were employed to assess ICC cell proliferation, and Transwell assays were performed to estimate the invasion and migration abilities of ICC cells. The capillary tube formation assay was applied to explore the angiogenic effects of HOXB7. A xenograft tumor model was established in nude mice to assess the role of HOXB7 in tumor growth and lung metastasis. The results showed higher expression of HOXB7 in ICC tissues than in noncancerous tissues, and this increased expression was significantly associated with a poor prognosis. In addition, HOXB7 overexpression enhanced capillary tube formation, invasion and migration of ICC cells in vitro, whereas HOXB7 knockdown produced the opposite results in vitro. Moreover, the role of HOXB7 in promoting tumor growth and metastasis was verified in vivo. Further investigation revealed that the expression levels of MMP2, MMP9, VEGFa, and IL8 were elevated by HOXB7 and that the ERK pathway was activated. Our results demonstrate the prognostic value of HOXB7 and its role in metastasis and angiogenesis in ICC. HOXB7 upregulated MMP2, MMP9, VEGFa, and IL8 expression via the ERK pathway to accelerate the malignant progression of ICC.