CircRNA circBACH1 facilitates hepatitis B virus replication and hepatoma development by regulating the miR-200a-3p/MAP3K2 axis.

BACKGROUND: Hepatitis B virus (HBV) is a top contributor to hepatoma. Circular RNAs (circRNAs) have been elucidated to have a close connection with HBV-induced hepatoma. This study aimed to explore the role of circRNA BTB domain and CNC homolog 1 (circBACH1) in HBV replication and hepatoma progression, as well as the potential mechanistic pathway. METHODS: Quantitative real-time polymerase chain reaction (qRT-PCR) assay was performed to assess the expression of circBACH1, microRNA (miR)-200a-3p, and mitogen-activated protein kinase kinase kinase 2 (MAP3K2). HBV replication was determined by enzyme-linked immunosorbent assay (ELISA) and qRT-PCR assay. Cell viability and clonogenicity were detected via Cell Counting Kit-8 (CCK-8) assay and colony formation assay, respectively. Cell metastasis was examined by Transwell assay and wound healing assay. Annexing-V/PI staining was employed to monitor cell apoptosis using flow cytometry. Levels of MAP3K2, proliferation- and apoptosis-related proteins were analyzed by Western blotting. Target interaction between miR-200a-3p and circBACH1 or MAP3K2 was confirmed by dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay. The role of circBACH1 in vivo was investigated by xenograft model assay. RESULTS: Expression of circBACH1 and MAP3K2 was increased, while miR-200a-3p expression was decreased in HCC tissues and HBV-transfected hepatoma cells. Depletion of circBACH1 or miR-200a-3p overexpression impeded HBV replication, proliferation, and metastasis in HBV-transfected hepatoma cells. CircBACH1 was able to regulate MAP3K2 expression by sponging miR-200a-3p. CircBACH1 regulated HBV replication and hepatoma progression through the miR-200a-3p/MAP3K2 pathway. Moreover, circBACH1 deficiency hampered tumor growth in vivo. CONCLUSION: CircBACH1 knockdown had inhibitory effects on HBV replication and hepatoma progression, at least partly by modulating the miR-200a-3p/MAP3K2 axis.

PDCD1 polymorphism amplifies the predisposing effect conferred by CTLA4 polymorphism in chronic hepatitis B virus infection.

Programmed cell death 1 (PDCD-1) and cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) both negatively regulate the T-cell response in chronic hepatitis B virus (HBV) infection. This study determined genotypes of PDCD1 -606 G/A and +8669 G/A and CTLA4 -318 C/T and +49 A/G polymorphisms in 172 chronic HBV patients and 145 healthy controls and analyzed the interaction between these polymorphisms of the 2 genes. The results indicated that carriage of the PDCD1 +8669 A allele was increased in HBV patients carrying the CTLA4 -318 CC genotype and carrying the CTLA4 +49 AA genotype compared with controls carrying the CTLA4 -318 CC genotype (80.2% vs 64.8%, p = 0.002, odds ratio [OR] = 2.202, 95% confidence interval [95% CI] = 1.326-3.656) and carrying the CTLA4 +49 AA genotype (18.6% vs 9.7%, p = 0.024, OR = 2.139, 95% CI = 1.093-4.187), respectively. More obviously, carriage of the PDCD1 +8669 AA genotype was significantly increased in HBV patients carrying the CTLA4 +49 AA genotype compared with controls carrying the same CTLA4 +49 genotype (14.0% vs 3.4%, p = 0.001, OR = 4.541, 95% CI = 1.686-12.230). These results suggest that the PDCD1 +8669 A allele and AA genotype may amplify the predisposing effect conferred by the CTLA4 polymorphism through PDCD1 and CTLA4 gene interaction in chronic HBV infection.

Associations between cytotoxic T lymphocyte-associated antigen-4 polymorphisms and serum tumor necrosis factor-α and interferon-γ levels in patients with chronic hepatitis B virus infection.

BACKGROUND: Cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) polymorphism, which may affect host immune response including cytokines production, is thought to be associated with hepatitis B virus (HBV) infection. This study investigated the associations between CTLA4 polymorphism and serum tumor necrosis factor (TNF)-α and interferon (IFN)-γ levels in patients with chronic HBV infection. METHODS: CTLA4 promoter -318C/T and exon 1 +49A/G polymorphisms and serum TNF-α and IFN-γ levels were determined in 172 patients with chronic HBV infection and 145 healthy controls. RESULTS: The genotype of CTLA4 -318C/T polymorphism had no association to TNF-α and IFN-γ levels. Serum levels of TNF-α and IFN-γ in chronic HBV patients with +49GG genotype were lower than those with +49AG genotype (p = 0.030 and p = 0.042, respectively), and haplotypes -318C + 49A and -318C + 49G seemed to have no significant effects on TNF-α and IFN-γ levels. CONCLUSIONS: CTLA4 +49GG genotype was associated to lower TNF-α and IFN-γ levels in patients with chronic HBV infection but this association was diminished by haplotype formation with -318C/T alleles, indicating that the influence of CTLA4 -318C/T and +49A/G polymorphisms on the susceptibility and disease progress of chronic HBV infection may not be effectuated by affecting TNF-α and IFN-γ secretion.

CTLA-4 exon 1 +49 polymorphism alone and in a haplotype with -318 promoter polymorphism may confer susceptibility to chronic HBV infection in Chinese Han patients.

Cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) plays a pivotal role in regulating T cell activation, which is believably critical for the outcome of hepatitis B virus (HBV) infection. The expression and function of CTLA-4 may be affected by gene polymorphisms. This study investigated the influence of CTLA-4 polymorphisms on disease susceptibility in Chinese Han patients with chronic HBV infection. CTLA-4 +49A/G and -318C/T polymorphisms were evaluated by DNA amplification with polymerase chain reaction followed by the restriction fragment length polymorphism analysis. The patients with chronic HBV infection had higher frequencies of genotype AA and allele A of CTLA-4 +49A/G polymorphism. The haplotype +49A-318C was significantly over-represented (P < 0.001) and haplotype +49G-318C under-represented (P = 0.006) in the patients. The +49GG genotype was more frequent (P = 0.009) and +49A allele was less frequent in patients with lower ALT levels (P = 0.012) in HBeAg positive chronic hepatitis B. It is indicated that CTLA-4 +49A/G polymorphism alone and in a haplotype with -318C allele may confer susceptibility to chronic HBV infection in Chinese Han patients.

Association of polymorphisms of programmed cell death-1 gene with chronic hepatitis B virus infection.

Programmed cell death-1 (PD-1) plays a critical role in regulating T-cell function during hepatitis B virus (HBV) infection. The present study investigated the relationships between the polymorphisms of the PD-1 gene and the susceptibility to chronic HBV infection. Single nucleotide polymorphisms (SNPs) in PD-1 gene at positions -606G/A (PD-1.1) and +8669 G/A (PD-1.6) were analyzed by bidirectional PCR amplification of specific alleles (Bi-PASA) in 198 chronic HBV patients and 280 controls. Although the genotype and allele frequencies of PD-1.1 were not different between chronic HBV patients and controls, the genotype and allele frequencies of PD-1.6 were significantly different. PD-1.6 GG genotype and the combination of genotypes with G allele were less frequent in HBV patients than in controls (p = 0.007 and p = 0.031, respectively). The allele G was also less frequent in patients than in controls (p = 0.006). Haplotype PD-1.1G/PD-1.6G was less frequent in patients than in controls (p = 0.001). Cirrhosis patients had a lower frequency of PD-1.6 G allele compared with controls (p = 0.007). Our findings, firstly reporting the association between PD-1 polymorphism and HBV infection, suggest that PD-1 gene may be one of the genes predisposing to chronic HBV infection and disease progression.

Higher pretherapy and significant decrease during the first 12 months of therapy in serum laminin levels may associate with hepatitis B e antigen seroconversion in chronic hepatitis B patients treated with lamivudine.

Laminin participates in regulating immune response in addition to being a biomarker of liver fibrosis. Lamivudine has been shown to be able to restore cytotoxic T-cell response in chronic hepatitis B. In this study, fifty-two patients with HBeAg-positive chronic hepatitis B received lamivudine treatment for more than 12 months. Serum laminin levels were determined at baseline and during treatment and analyzed regarding treatment responses at the end of 12 months of therapy. The results showed that laminin levels at 12 months of treatment in patients who lost HBeAg were significantly lower compared with baseline (P = 0.001). The baseline laminin levels were higher in HBeAg seroconversion group than those without seroconversion (P = 0.037). Compared with baseline, the levels of serum laminin in HBeAg seroconversion group showed significant decrease (P = 0.001). It is concluded that higher pretherapy and significant decrease during the first 12 months of therapy in laminin levels may associate with HBeAg seroconversion in chronic hepatitis B patients treated with lamivudine, indicating the possible novel information of laminin for clinical reference.