MYH9 has dual functions in tumors. However, its role in inducing tumor stemness in hepatocellular carcinoma (HCC) is not yet determined. Here, we found that MYH9 is an effective promoter of tumor stemness that facilitates hepatocellular carcinoma pathogenesis. Importantly, targeting MYH9 remarkably improved the survival of hepatocellular carcinoma-bearing mice and promoted sorafenib sensitivity of hepatocellular carcinoma cells in vivo. Mechanistic analysis suggested that MYH9 interacted with GSK3β and reduced its protein expression by ubiquitin-mediated degradation, which therefore dysregulated the β-catenin destruction complex and induced the downstream tumor stemness phenotype, epithelial-mesenchymal transition, and c-Jun signaling in HCC. C-Jun transcriptionally stimulated MYH9 expression and formed an MYH9/GSK3β/β-catenin/c-Jun feedback loop. X protein is a hepatitis B virus (HBV)-encoded key oncogenic protein that promotes HCC pathogenesis. Interestingly, we observed that HBV X protein (HBX) interacted with MYH9 and induced its expression by modulating GSK3β/β-catenin/c-Jun signaling. Targeting MYH9 blocked HBX-induced GSK3β ubiquitination to activate the β-catenin destruction complex and suppressed cancer stemness and EMT. Based on TCGA database analysis, MYH9 was found to be elevated and conferred poor prognosis for hepatocellular carcinoma patients. In clinical samples, high MYH9 expression levels predicted poor prognosis of hepatocellular carcinoma patients. These findings identify the suppression of MYH9 as an alternative approach for the effective eradication of CSC properties to inhibit cancer migration, invasion, growth, and sorafenib resistance in HCC patients. Our study demonstrated that MYH9 is a crucial therapeutic target in HCC.

PurposeLiver fibrosis is a worldwide health issue. Development of effective new drugs for treatment of this disease is of great importance. This study investigated the therapeutic effects of ferulic acid on liver fibrosis in vitro and in vivo.Materials and methodsHuman hepatic stellate cell line (HSC) LX-2 was used for in vitro assays. Transforming growth factor β1 (TGF-β1) was used to induce hepatic fibrosis in LX-2 cells. Western blot was used to detect protein levels of collagen I, fibronectin, α-smooth muscle actin (SMA), p-Smad2, p-Smad3, p-p38, and p-JNK. Gene expression was measured by RT-qPCR. Fluorescence staining was used to determine localization of Smad4. CCl4-induced hepatic fibrosis in SD rats was used as an in vivo model. Histological features were detected by hematoxylin and eosin staining. Levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), hexadecenoic acid (HA), and hydroxyproline (Hyp) were measured by ELISA.ResultsTGF-β1 treatment significantly increased levels of collagen I, fibronectin, α-SMA, p-Smad2, p-Smad3, and Smad4 in LX-2 cells. Ferulic acid improved TGF-β1-induced hepatic fibrosis via regulation of the TGF-β1/Smad pathway. Consistent with in vitro data, CCl4 caused severe hepatic fibrosis in SD rats, as determined by ALT, AST, HA, and Hyp upregulation. Protein levels of p-Smad2 and p-Smad3 in liver tissues were significantly increased following treatment with CCl4. All CCL4-induced changes were markedly attenuated by ferulic acid treatment.ConclusionFerulic acid potently improved hepatic fibrosis via inhibition of the TGF-β1/Smad pathway in vitro and in vivo. These findings provided evidence for potential use of ferulic acid to treat or prevent liver fibrosis.

Cancer stem cells (CSCs) are the key factor in determining cancer recurrence, metastasis, chemoresistance and patient prognosis in hepatocellular carcinoma (HCC). The role of miR-5188 in cancer stemness has never been documented. In this study, we investigated the clinical and biological roles of miR-5188 in HCC. Methods: MiRNA expression in HCC was analyzed by bioinformatics analysis and in situ hybridization. The biological effect of miR-5188 was demonstrated in both in vitro and in vivo studies through the ectopic expression of miR-5188. The target gene and molecular pathway of miR-5188 were characterized using bioinformatics tools, dual-luciferase reporter assays, gene knockdown, and rescue experiments. Results: MiR-5188 was shown to be upregulated and confer poor prognosis in HCC patient data from TCGA database. MiR-5188 was subsequently identified as a significant inducer of cancer stemness that promotes HCC pathogenesis. Specifically, the targeting of miR-5188 by its antagomir markedly prolonged the survival time of HCC-bearing mice and improved HCC cell chemosensitivity in vivo. Mechanistic analysis indicated that miR-5188 directly targets FOXO1, which interacts with β-catenin in the cytoplasm to reduce the nuclear translocation of β-catenin and promotes the activation of Wnt signaling and downstream tumor stemness, EMT, and c-Jun. Moreover, c-Jun transcriptionally activates miR-5188 expression, forming a positive feedback loop. Interestingly, the miR-5188-FOXO1/β-catenin-c-Jun feedback loop was induced by hepatitis X protein (HBX) through Wnt signaling and participated in the HBX-induced pathogenesis of HCC. Finally, analyses of transcriptomics data and our clinical data supported the significance of the abnormal expression of the miR-5188 pathway in HCC pathogenesis. Conclusions: These findings present the inhibition of miR-5188 as a novel strategy for the efficient elimination of CSCs to prevent tumor metastasis, recurrence and chemoresistance in patients with hepatocellular carcinoma. Our study highlights the importance of miR-5188 as a tumor stemness inducer that acts as a potential target for HCC treatment.

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