As the subfamily of noncoding RNA, microRNAs (miRNAs) broadly regulate the development of cancers, while their dysregulation and function in human hepatocellular carcinoma (HCC) remains largely unclear. Here, we found the expression level of microRNA-147b (miR-147b) is increased aberrantly in HCC tumor tissues, and its expression positively correlates to the tumor severity. In both MTT and colony formation assay, knockdown of miR-147b dramatically inhibits in vitro proliferation of HCC cell lines. More interestingly, we also performed in vivo tumorigenesis assay and found that miR-147b can regulate in vivo tumorigenesis in nude mice xenograft models. The ubiquitin-conjugating enzyme E2N (UBE2N) was identified directly and functionally targeted by miR-147b. The mRNA level of UBE2N is increased in HCC tumors or cell lines. Restoring UBE2N expression level in tumor cells leads to inhibition of cell proliferation, which mimics the effect upon miR-147b knockdown in the same cells. These data elucidated the oncogenic role of miR-147b in HCC development and progression with therapeutic target potentials.

Transcriptional repressor Pokemon is a critical factor in embryogenesis, development, cell proliferation, differentiation, and oncogenesis, thus behaving as an oncogene. Oncomine database suggests a potential correlation between the expressions of Pokemon and Sprouty1. This study investigated the regulatory role of Pokemon in Sprouty1 expression and the effect on liver cancer cell growth and proliferation, revealing a novel miR-21-mediated regulatory circuit. In normal (HL-7702) and cancer (QGY-7703) liver cell lines, Sprouty1 expression is inversely correlated with Pokemon levels. Targeted expression or siRNA-mediated silencing showed that Pokemon is a repressor of Sprouty1 expression at both mRNA and protein levels, but Pokemon cannot affect the promoter activity of Sprouty1. Sprouty1 is a target of miR-21 and interestingly, we found that miR-21 is up-regulated by Pokemon in liver cancer cells. Luciferase reporter assays showed that Pokemon up-regulated miR-21 transcription in a dose-dependent manner, and ChIP assay exhibited a direct binding of Pokemon to the miR-21 promoter at -747 to -399 bp. Site-directed mutagenesis of the GC boxes at -684 to -679 bp and -652 to -647 bp of miR-21 promoter abolished the regulatory activity by Pokemon. Furthermore, we found that the modulation of Pokemon and miR-21 expression affected the growth and proliferation of liver cancer cells QGY-7703. In summary, our findings demonstrate that Pokemon suppresses Sprouty1 expression through a miR-21-mediated mechanism, affecting the growth and proliferation of liver cancer cells. This study recognized miR-21 and Sprouty1 as novel targets of the Pokemon regulatory network.

A novel approach to synthesize RITA by practical palladium-catalyzed C-C bond-forming Suzuki reactions at room temperature was developed, which was used for deriving a series of substituted tricyclic α-heteroaryl (furan/thiophene) analogues of RITA under mild conditions. These novel analogues showed notable antiproliferative activity against cancer cell lines with wild-type p53 (i.e., HCT116, A549, MCF-7 and K562), but much less activity in HCT116/p53(-/-) cells. In particular, compound 1f demonstrated promising antiproliferative activity compared to RITA, with IC(50) = 28 nM in MCF-7 vs. 54 nM for RITA, and cancer cell selectivity. Compound 1f markedly activated p53 in HCT116 cells at 100 nM, triggering apoptosis. Importantly, we found that both RITA and compound 1f induced G(0)/G(1) cell cycle arrest by up-regulating miR-34a, which in turn down-regulated the expression of cell cycle-related proteins CDK4 and E2F1. In summary, this study reports an effective synthetic approach for RITA and its analogues, and elucidates a novel antiproliferative mechanism of these compounds.

BackgroundTransforming growth factor-beta (TGF-β) signaling is essential in initialization and progression of hepatocellular carcinoma (HCC). Therefore, a treatment targeting TGF-β pathway may be a promising option for HCC control.MethodsFirst, publicly available RNA-seq datasets and clinical characteristics of 374 HCC patients in The Cancer Genome Atlas (TCGA) database were downloaded. Then, Cox regression analysis and LASSO analysis were used to construct a prognostic model for TGF-β family genes. The area under the curve (AUC) of the risk signature was calculated to evaluate the predictive power of the model. Cox regression analysis was applied to predict whether TGF-β1 can be an independent prognosis factor for HCC. Next, hazard ratio and survival analyses were performed to investigate the correlation between TGF-β1 expression and survival time. Furthermore, differential expression level of TGF-β1 in HCC tissues and cells was determined. In addition, Gene Set Enrichment Analysis (GSEA) identified the top significantly activated and inhibited signal pathways related to high expression of TGF-β1. Finally, the CIBERSORT tool was adopted to correlate the tumor-infiltrating immune cells (TICs) with TGF-β1 expression in HCC cohorts.ResultsCox regression analysis and LASSO analysis revealed that seven TGF-β family members (including TGF-β1) could be used as prognostic factors for HCC. Interestingly, TGF-β1 was demonstrated to be an independent prognostic factor of HCC. RT-qPCR and immunofluorescence staining confirmed the high expression of TGF-β1 in HCC cell lines and tissues, which is significantly related to pathological classifications, poor prognosis, and short survival time. Finally, GSEA and CIBERSORT analyses suggested that TGF-β1 may interact with various immune cells and influence the prognosis of HCC patients through Tregs and γδ T cells.ConclusionWe established a novel prognostic prediction method to predict the risk scores of TGF-β genes in HCC prognosis. TGF-β1 is highly expressed in HCC cell lines and tissues, correlates to poor prognosis, and thus can be used as a potential biomarker to predict HCC prognosis. We showed that TGF-β1 may play its roles in HCC prognosis by modulating the immune microenvironment of tumor cells. Our data may shed more light on better understanding the role of TGF-β1 in HCC prognosis.

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