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Figure S4 from Genetic Polymorphisms Predisposing the Interleukin 6–Induced APOBEC3B-UNG Imbalance Increase HCC Risk via Promoting the Generation of APOBEC-Signature HBV Mutations

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posted on 2023-03-31, 21:05 authored by Wenbin Liu, Jianfeng Wu, Fan Yang, Longteng Ma, Chong Ni, Xiaomei Hou, Ling Wang, Aijing Xu, Jiahui Song, Yang Deng, Linfeng Xian, Zixiong Li, Shuo Wang, Xi Chen, Jianhua Yin, Xue Han, Chengzhong Li, Jun Zhao, Guangwen Cao

The effect of PMA on the expression of APOBEC3B and UNG as well as the activities of the transcriptional regulatory sequences with different rs2267401 and rs3890995 genotypes

Funding

National Key Basic Research Program of China

National Natural Science Foundation of China

History

ARTICLE ABSTRACT

APOBEC3-UNG imbalance contributes to hepatitis B virus (HBV) inhibition and somatic mutations. We aimed to explore the associations between hepatocellular carcinoma (HCC) risk and genetic polymorphisms predisposing the imbalance.Experimental Design: Genetic polymorphisms at APOBEC3 promoter and UNG enhancer regions were genotyped in 5,621 participants using quantitative PCR. HBV mutations (nt.1600–nt.1945, nt.2848–nt.155) were determined by Sanger sequencing. Dual-luciferase reporter assay was applied to detect the transcriptional activity. Effects of APOBEC3B/UNG SNPs and expression levels on HCC prognosis were evaluated with a cohort of 400 patients with HCC and public databases, respectively. APOBEC3B rs2267401-G allele and UNG rs3890995-C allele significantly increased HCC risk. rs2267401-G allele was significantly associated with the generation of APOBEC-signature HBV mutation whose frequency consecutively increased from asymptomatic HBV carriers to patients with HCC. Multiplicative interaction of rs2267401-G allele with rs3890995-C allele increased HCC risk, with an adjusted OR (95% confidence interval) of 1.90 (1.34–2.81). rs2267401 T-to-G and rs3890995 T-to-C conferred increased activities of APOBEC3B promoter and UNG enhancer, respectively. IL6 significantly increased APOBEC3B promoter activity and inhibited UNG enhancer activity, and these effects were more evident in those carrying rs2267401-G and rs3890995-C, respectively. APOBEC3B rs2267401-GG genotype, higher APOBEC3B expression, and higher APOBEC3B/UNG expression ratio in HCCs indicated poor prognosis. APOBEC-signature somatic mutation predicts poor prognosis in HBV-free HCCs rather than in HBV-positive ones. Polymorphic genotypes predisposing the APOBEC3B-UNG imbalance in IL6-presenting microenvironment promote HCC development, possibly via promoting the generation of high-risk HBV mutations. This can be transformed into specific prophylaxis of HBV-caused HCC.