RFX5 promotes the progression of hepatocellular carcinoma through transcriptional activation of KDM4A.

Regulatory factor X-5 (RFX5) represents a key transcription regulator of MHCII gene expression in the immune system. This study aims to explore the molecular mechanisms and biological significance of RFX5. Firstly, by analyzing ENCODE chromatin immunoprecipitation (ChIP)-seq in HepG2 and TCGA RNA-seq data, we discovered lysine-specific demethylase 4A (KDM4A), also named JMJD2A, to be a major downstream target gene of RFX5. Moreover, RFX5 was verified to bind directly to the KDM4A's promoter region and sequentially promoted its transcription determined by the ChIP-PCR assay and luciferase assay. In addition, RFX5-dependent regulation of KDM4A was demonstrated in HCC. Compared with adjacent non-tumor tissues, the expression levels of KDM4A were significantly raised in HCC tumor tissues. Notably, elevated levels of KDM4A were strongly correlated with HCC patient prognosis. Functionally, KDM4A overexpression largely rescued the growth inhibitory effects of RFX5 deletion, highlighting KDM4A as a downstream effector of RFX5. Mechanistically, the RFX5-KDM4A pathway promoted the progression of the cell cycle from G0/G1 to S phase and was protective against cell apoptosis through regulation of p53 and its downstream genes in HCC. In conclusion, RFX5 could promote HCC progression via transcriptionally activating KDM4A expression.

Genome-scale CRISPR activation screening identifies a role of ELAVL2-CDKN1A axis in paclitaxel resistance in esophageal squamous cell carcinoma.

Neoadjuvant chemotherapy (NAC) may provide survival benefits for patients with advanced esophageal squamous cell carcinoma. However, tumor cells can display primary or secondary resistance to paclitaxel (PTX), a primary component of induction chemotherapy regimen. To identify genes capable of conveying PTX resistance, we performed a genome-wide CRISPR transcriptional activation library in human KYSE-180 cells. High throughput next generation sequencing was further applied to establish the phenotype-to-genotype relationship. Our highest-ranking hits are CDKN1A, TSPAN4, ELAVL2, JUNB and PAAF1. We generated evidence that esophageal tumors with high CDKN1A, ELAVL2 and TSPAN4 levels, quantified using qRT-PCR and Western blot assays, showed poorer chemotherapy response. Higher expression levels of TSPAN4 and ELAVL2 protein are independent risk factors for poor chemotherapy response in ESCC patients. We then found that overexpression of CDKN1A, ELAVL2 or TSPAN4 in ESCC cell lines significantly promoted the resistance to PTX by inhibiting cell apoptosis. Interestingly, ESCC cells overexpressed CDKN1A, ELAVL2 or TSPAN4 also acquired resistance to cisplatin (DDP). This phenomenon may be explained by cross-resistance of chemotherapy. We additionally found an association between ELAVL2 and CDKN1A, which may be regarded as the upstream and downstream factors that synergistically involved in the regulation of chemo-resistance in ESCC. Therefore, our study demonstrated that the genome-wide CRISPR activation library is a powerful strategy for the discovery of chemo-resistant genes critical for ESCC and we reported the first evidence that the ELAVL2-CDKN1A axis may be an important mechanism involved in chemo-resistance in ESCC.

Regulatory factor X5 promotes hepatocellular carcinoma progression by transactivating tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein theta and suppressing apoptosis.

BACKGROUND: Our previous studies have shown that regulatory factor X5 (RFX5), a classical transcription regulator of MHCII genes, was obviously overexpressed in hepatocellular carcinoma (HCC) tumors. However, the role of RFX5 in the carcinogenesis and progress of HCC remains unknown. This study aimed to reveal its biological significance and the underlying mechanism in HCC. METHODS: RFX5 mRNA expression level and copy number variation in HCC tumors and cell lines were determined by analyzing deposited data sets in the Cancer Genome Atlas and Gene Expression Omnibus database. The biological significance of RFX5 in HCC was investigated by monitoring the colony formation and subcutaneous tumor growth capacity when RFX5 was silenced with lentiviral short hairpin RNA and CRISPR/Cas9 system in HCC cell lines. The downstream gene transcriptionally activated by RFX5 in HCC cells was determined by chromatin immunoprecipitation and luciferase reporter assay. The involvement of tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein theta (YWHAQ) in HCC development was further determined by performing colony formation rescue assay and subcutaneous tumor growth rescue experiment. The association of YWHAQ with recurrence-free survival of patients with HCC was assessed by Kaplan-Meier analysis. Moreover, apoptosis level and the protein level of p53 pathway were determined to reveal the mechanism of RFX5 in driving HCC development. RESULTS: RFX5 was amplified and highly overexpressed in HCC tumor tissues compared with the corresponding non-tumor tissues. The mRNA expression level of RFX5 was significantly correlated with its DNA copy number (r = 0.4, P < 0.001). Functional study demonstrated that RFX5 was required for both clonogenic forming in vitro and subcutaneous tumor growth in vivo of HCC cells. Further study identified YWHAQ, namely 14-3-3 tau, as a key downstream transcriptional target gene of RFX5, which was tightly regulated by RFX5 in HCC. Moreover, overexpression of YWHAQ largely rescued the clonogenic growth of HCC cells that was suppressed by RFX5 knockdown. In addition, overexpression of YWHAQ in primary tumor was linked to poor prognosis of patients with HCC. These results demonstrated that YWHAQ was a downstream effector of RFX5 in HCC. Notably, RFX5-YWHAQ pathway could protect cells from apoptosis by suppressing the p53 and Bax in HCC. CONCLUSION: RFX5 is a putative HCC driver gene that plays an important role in the development and progression of HCC by transactivating YWHAQ and suppressing apoptosis.

Effect of Upregulated DNA Replication and Sister Chromatid Cohesion 1 Expression on Proliferation and Prognosis in Hepatocellular Carcinoma.

BACKGROUND: DNA replication and sister chromatid cohesion 1 (DSCC1) (also called DCC1) is a component of an alternative replication factor C complex that loads proliferating cell nuclear antigen onto DNA during S phase of the cell cycle. It is located at 8q24 and frequently amplified in hepatocellular carcinoma (HCC). However, the role of DSCC1 in the carcinogenesis and progress of HCC has not been fully investigated. Here, we aimed to assert the importance of DSCC1 in the HCC. METHODS: In this study, copy number variation data and RNA sequencing data were used to calculate the DNA copy number and mRNA expression of DSCC1 in HCC. Quantitative polymerase chain reaction, Western blotting, and immunohistochemistry analysis were used to determine the mRNA and protein level of DSCC1 in HCC. The Kaplan-Meier analysis and univariate and multivariate Cox regression analysis were used to assess the association of DSCC1 with the overall survival (OS) of HCC patients. Moreover, lentiviral shRNA was used to knockdown DSCC1, and then, colony-forming assay, cell cycle assay, and cell proliferation assay were performed to evaluate the impact of DSCC1 silencing on HCC cell lines. RESULTS: We found that DSCC1 was amplified and highly expressed in HCC tumor tissues than in nontumor tissues. We then found that the overexpression of both mRNA and protein of DSCC1 was linked to the bad prognosis of HCC patients. Astonishingly, the protein level of DSCC1 was an independent prognostic factor for OS (hazard ratio, 1.79; 95% confidence interval, 1.17-2.74; P = 0.007). Furthermore, the clonogenic capacity of DSCC1-amplified HCC cell lines (MHCC-97H, MHCC-97L, and Hep3B) was significantly inhibited by transduction of a lentiviral shRNA that targets DSCC1. We also showed that knockdown of DSCC1 induced G0-G1 cell cycle arrest (increased from 60% to more than 80%) and greatly inhibited the proliferation of HCC cell lines. CONCLUSION: These results suggest that DSCC1 is a putative HCC driver gene that promotes proliferation and is associated with poor prognosis in HCC.

Direct-acting Antiviral Agents Resistance-associated Polymorphisms in Chinese Treatment-naïve Patients Infected with Genotype 1b Hepatitis C Virus.

BACKGROUND: It has been reported that several baseline polymorphisms of direct-acting antivirals (DAAs) agents resistance-associated variants (RAVs) would affect the treatment outcomes of patients chronically infected with hepatitis C virus (CHC). The aim of this study is to investigate the prevalence of DAAs RAVs in treatment-naÏve GT1b CHC patients. METHODS: Direct sequencing and ultra-deep sequencing of the HCV NS3, NS5A, and NS5B gene were performed in baseline serum samples of treatment-naÏve patients infected with genotype 1b hepatitis C virus (HCVs). RESULTS: One hundred and sixty CHC patients were studied. Complete sequence information was obtained for 145 patients (NS3), 148 patients (NS5A), and 137 patients (NS5B). Treatment-failure associated variants of DAAs were detected: 56.6% (82/145) of the patients presented S122G for simeprevir (NS3 protease inhibitor); 10.1% (14/148) of the patients presented Y93H for daclatasvir and ledipasvir (NS5A protein inhibitors); 94.2% (129/137) of the patients presented C316N for sofosbuvir (NS5B polymerase inhibitor). Nearly, all of the DAAs RAVs detected by ultra-deep sequencing could be detected by direct sequencing. CONCLUSIONS: The majority of genotype 1b CHC patients in China present a virus population carrying HCV DAAs RAVs. Pretreatment sequencing of HCV genome might need to be performed when patients infected with GT1b HCV receiving DAAs-containing regimens in China. Population sequencing would be quite quantified for the work.

2',3'-cyclic nucleotide 3'-phosphodiesterases inhibit hepatitis B virus replication.

2',3'-cyclic nucleotide 3'-phosphodiesterase (CNP) is a member of the interferon-stimulated genes, which includes isoforms CNP1 and CNP2. CNP1 is locally expressed in the myelin sheath but CNP2 is additionally expressed at low levels outside the nervous system. CNPs regulate multiple cellular functions and suppress protein production by association with polyadenylation of mRNA. Polyadenylation of Hepatitis B virus (HBV) RNAs is crucial for HBV replication. Whether CNPs interact with polyadenylation signal of HBV RNAs and interfere HBV replication is unknown. In this study, we evaluated expressions of CNP isoforms in hepatoma cell lines and their effects on HBV replication. We found that CNP2 is moderately expressed and gently responded to interferon treatment in HepG2, but not in Huh7 cells. The CNP1 and CNP2 potently inhibited HBV production by blocking viral proteins synthesis and reducing viral RNAs, respectively. In chronic hepatitis B patients, CNP was expressed in most of HBV-infected hepatocytes of liver specimens. Knockdown of CNP expression moderately improved viral production in the HepG2.2.15 cells treated with IFN-α. In conclusion, CNP might be a mediator of interferon-induced response against HBV.

[Correlation between interleukin-28B genetic polymorphisms and primary hepatocellular carcinoma].

OBJECTIVE: To explore the correlation between single nucleotide polymorphisms (SNPs) of interleukin-28B (IL-28B) gene and the susceptibility to primary hepatocellular carcinoma (HCC). METHODS: A total of 300 histologically confirmed HCC cases (from November 2001 to April 2010) and 310 healthy controls with no history of chronic hepatitis B or hepatocellular carcinoma (2009-2010) were selected from a hospital in Guilin and a hospital in Beijing for this case-control study.139 HCC patients in the case group had complete clinical tracking data. All the subjects were Han Chinese, with no age or gender restrictions.2 ml peripheral blood samples were drawn from each subject with informed consent. SNP of rs12972991, rs4803223, rs8099917 and rs12979860 four loci in IL-28B gene were analyzed by matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF). RESULTS: The frequencies of C allele at rs12972991, G allele at rs8099917 and G allele at rs4803223 were 6.7% (40/598), 7.9% (47/598) and 10.0% (59/588) respectively in case group; all higher than the corresponding frequencies in control group, separately 2.9% (18/618), 4.1% (25/616) and 3.6% (21/608). The differences were statistically significant (χ2=9.542, 7.858, 20.736, P values all<0.05). The above alleles could increase the risk of HCC, and the OR (95%CI) values were separately 1.67 (1.13-2.46), 1.49 (1.08-2.06) and 2.91 (1.79-4.72). The genotype frequencies of AC+CC at rs12972991, GT+GG at rs8099917, GA+GG at rs4803223 were 13.0% (39/299), 14.7% (44/299) and 19.0% (56/296) respectively in case group; while the frequencies were lower in control group, separately 5.8% (18/309), 8.1% (25/308) and 6.6% (20/304). The differences were statistically significant (χ2=9.319, 6.557, 20.948, P values all<0.05). These genotypes may increase the risk of HCC, and the adjusted OR (95%CI) values were 2.24 (1.31-3.83), 1.81 (1.14-2.88) and 2.90 (1.78-4.70), respectively. The stratified analysis of the clinical data indicated that the frequency of genotype GA+GG at rs4803223 was 50.0% (13/26) in patients of tumor thrombosis in portal vein (TTPV), higher than the frequency of genotype AA (21.1%, 23/109). The difference was statistically significant (χ2=8.965, P=0.003). CONCLUSION: The results suggested that IL-28B gene polymorphisms was correlated to the susceptibility to HCC in Chinese Han ethnic population. Among them, GA + GG genotype at rs4803223 could increase the risk of TTPV in HCC patients.

In vitro inhibition of HBV replication by a novel compound, GLS4, and its efficacy against adefovir-dipivoxil-resistant HBV mutations.

BACKGROUND: HBV infection continues to be an important worldwide cause of morbidity and mortality. Patients with chronic hepatitis B can be successfully treated using nucleoside/nucleotide analogues. However, drug-resistant HBV mutants frequently arise, leading to treatment failure and progression to liver disease. Here, we report the effects of GLS4, a non-nucleosidic inhibitor that exhibits a novel and highly specific anti-HBV activity. METHODS: The median inhibitory concentrations (IC(50)s) of GLS4 on HBV were measured by Southern blotting. HBV capsid and core protein levels were detected by immunoblotting. To determine the antiviral activity of GLS4 against adefovir dipivoxil (ADV)-resistant HBV mutants, HepG2 cells transiently transfected with PUC-HBV1.2 plasmids that contained one of three major ADV-resistant mutations (rtA181T, rtA181V and rtN236T) were treated with GLS4. Intracellular HBV replicative intermediates were detected by Southern blotting. The effect on the in vitro assembly of HBV capsid protein was examined using dynamic light scattering and electron microscopy. RESULTS: The IC(50) of GLS4 was 0.012 µM, which is significantly lower than that of lamivudine (0.325 µM). Immunoblot analysis of HepG2.2.15 cells and transiently transfected HepG2 cells indicated that GLS4 treatment interfered with the formation of core particles (assembly). The ADV-resistant HBV mutant strains were also sensitive to GLS4. Upon examining the in vitro assembly of HBV core protein 149 by electron microscopy, increased aberrant particles were observed after GLS4 treatment. CONCLUSIONS: GLS4 is a new and unique potential anti-HBV agent that possesses a different mechanism of action than existing therapeutic drugs.

Intestinal immune barrier integrity in rats with nonalcoholic hepatic steatosis and steatohepatitis.

BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) has emerged as the major cause of chronic liver injury. Intestinal barrier plays an important role in the pathogenis of NAFLD. The aim of this article was to assess intestinal immune barrier function during the development of NAFLD. METHODS: Totally 60 male Sprague-Dawley (SD) rats were divided into 2 groups: normal diet (ND) group and high-fat diet (HFD) group. NAFLD rat model was established in the HFD rat group. Portal blood endotoxin level was assessed by limulus test. The percentage of CD4+ cells and CD8+ cells in peripheral blood mononuclear cells (PBMC) and lymphocytes in Peyer's patches (PP) were analysed by flow cytometry. Intestinal secretory immunoglobulin A (SIgA) level was evaluated by enzyme-linked immunosorbent assay. Paired Student's t test was used for the statistic analysis. RESULTS: HFD rats presented with simple steatosis at the 4th and 8th week and progressed to nonalcoholic steatohepatitis at the 12th week. Elevated lipopolysaccharides (LPS) level in HFD rats was observed at the 8th week ((1.54 ± 0.30) times of ND group, P < 0.01). CD4/CD8 ratios in PBMC and PP of HFD rats were increased at the 4th week ((1.50 ± 0.47) and (1.63 ± 0.34) times of ND group, P < 0.05) and decreased at the 8th week ((0.50 ± 0.16) and (0.61 ± 0.26) times of ND group, P < 0.05). At the 12th week, CD4/CD8 ratio ((1.47 ± 0.46) times, P < 0.05) in PP increased to levels observed in the 4th week. Intestinal SIgA expression of HFD rats was remarkably up-regulated at 12th week ((2.70 ± 1.65) times, P < 0.05). CONCLUSION: Liver-gut axis in rats with NAFLD may mediate and improve intestinal immune function by increased CD4/CD8 ratio in PP and increased production of SIgA.

[Specific suppression in regulatory T cells by Foxp3 siRNA contributes to enhance the in vitro anti-tumor immune response in hepatocellular carcinoma patients].

OBJECTIVE: To design the suitable sequence siRNA of Foxp3 to interfere the function of regulatory T cells(Treg), and to evaluate whether the suppression of Treg could enhance the anti-tumor immune response in hepatocellular carcinoma patients or not. METHODS: Foxp3-specific siRNAs by chemical synthesis were delivered into regulatory T cells. The inhibition efficiencies of Foxp3-specific siRNAs were evaluated by real-time PCR and fluorescently stained for intracellular Foxp3 and analyzed using multiparameter FCM. The Foxp3(+) Treg subpopulation was selectively analyzed for surface expression levels of CD127, CTLA-4 and GITR. The suppression of Treg to CD4(+)CD25(-) T cells or anti-tumor specific CD8(+) T-cell responses induced by tumor specific antigen (NY-ESO-1b) was evaluated by CFSE, Elispot and Pentamer analysis. RESULTS: A subpopulation of Tregs with reduced levels of Foxp3 mRNA and protein mediated by siRNA was CD127 up-regulation and CTLA-4 or GITR down-regulation compared with those in Foxp3(high) Tregs. Knockdown of intracellular Foxp3 in Treg reduced suppression of Foxp3+ Treg to proliferative capacity of CD4(+)CD25(-) T cells. IFN-gamma released of NY-ESO-1-specific CD8(+) T cells from the group of Tregs with Foxp3 specific siRNA transfected was increased as compared with the group of Treg with non-specific control siRNA transfected(132+/-55 vs 27+/-11, P<0.05). Frequency of NY-ESO-1b-specific CD8(+) T cells by Pentamer analysis from the group of Tregs with Foxp3 specific siRNA transfected was increased as compared with the group of Treg with non-specific control siRNA transfected (0.21%+/-0.17% vs 0.57%+/-0.39%, P<0.05). CONCLUSION: Knockdown of intracellular Foxp3 in Treg mediated by siRNAs can inhibit the suppression of Foxp3+ Treg and enhance the anti-tumor immune response in hepatocellular carcinoma patients in vitro.

Expression of CIITA-related MHCII molecules in tumors linked to prognosis in hepatocellular carcinoma.

The prognosis of hepatocellular carcinoma (HCC) after surgery is poor due to its high recurrence rate. In order to unfold the mechanism of different recurrent-free survival (RFS) times following resection, expression profiling of tumor tissues from 32 HCC patients with different RFS time were used to identify differential expression of individual genes and signaling pathway components correlated with RFS time. Quantitative RT-PCR, Western blotting, and immunohistochemistry were used to validate the expression of selected genes. Up-regulation of several immune related genes and pathways, especially HLA II-related antigen presenting pathways, significantly correlated with longer RFS time. The expression of MHCII molecules were found to be mainly located in either CD68+ cells or CD45+ cells, and their expression significantly correlated with the expression of CIITA (HLA II genes transactivator) in the tumor. The results suggest that the high expression level of CIITA and MHCII molecules in hepatocellular carcinoma tissue is an effective prognostic marker for longer RFS time in HCC.