Molecular liver cancer prevention in cirrhosis by organ transcriptome analysis and lysophosphatidic acid pathway inhibition

Cirrhosis is a milieu that develops hepatocellular carcinoma (HCC), the second most lethal cancer worldwide. HCC prediction and prevention in cirrhosis are key unmet medical needs. Here we have established an HCC risk gene signature applicable to all major HCC etiologies: hepatitis B/C, alcohol, and non-alcoholic steatohepatitis. A transcriptome meta-analysis of >500 human cirrhotics revealed global regulatory gene modules driving HCC risk and the lysophosphatidic acid pathway as a central chemoprevention target. Pharmacological inhibition of the pathway in vivo reduced tumors and reversed the gene signature, which was verified in organotypic ex vivo culture of patient-derived fibrotic liver tissues. These results demonstrate the utility of clinical organ transcriptome to enable a strategy, namely, reverse-engineering precision cancer prevention

Genetic variation in FCER1A predicts peginterferon alfa-2a-induced hepatitis B surface antigen clearance in East Asian patients with chronic hepatitis B

In a multicenter, genome-wide association study to identify host genetic factors associated with treatment response in adult chronic hepatitis B patients, genotype data were obtained by microarray analysis from 1669 patients who received peginterferon alfa-2a for 6524 weeks with/without a nucleos(t)ide analog. Treatment response was assessed at least 24 weeks post-treatment, using serological and/or virological endpoints. Thirty-six single-marker analyses and a gene-by-gene analysis were conducted. No single nucleotide polymorphisms (SNPs) achieved genome-wide significance (P<5 7 10-8 ) in single-marker analyses, but suggestive associations (P<1 7 10-5 ) were identified for 116 SNPs. In gene-by-gene analyses, one gene, FCER1A (rs7549785), reached genome-wide significance (P=2.65 7 10-8 ) in East Asian patients for hepatitis B surface antigen (HBsAg) clearance, with a moderate effect size (odds ratio = 4.74). Eleven of 44 carriers (25%) of the A allele at rs7549785 achieved HBsAg clearance compared with 69/1051 (7%) noncarriers. FCER1A encodes the alpha subunit of the immunoglobulin E receptor. In a post hoc analysis of a homogenous patient subset, the strongest intra-genic association was for rs7712322 (POLR3G, P=7.21 7 10-7 ). POLR3G encodes the G subunit of the Polymerase (RNA) III enzyme, involved in sensing and limiting infection by intracellular bacteria and DNA viruses, and as a DNA sensor in innate immune responses. FCER1A (rs7549785), and possibly POLR3G (rs7712322), are shown to be associated with peginterferon alfa-2a response in adult patients with chronic hepatitis B. Independent confirmation of these findings is warranted (clinicaltrials.gov number NCT01855997). This article is protected by copyright. All rights reserved

Strand-resolved mutagenicity of DNA damage and repair.

DNA base damage is a major source of oncogenic mutations1. Such damage can produce strand-phased mutation patterns and multiallelic variation through the process of lesion segregation2. Here we exploited these properties to reveal how strand-asymmetric processes, such as replication and transcription, shape DNA damage and repair. Despite distinct mechanisms of leading and lagging strand replication3,4, we observe identical fidelity and damage tolerance for both strands. For small alkylation adducts of DNA, our results support a model in which the same translesion polymerase is recruited on-the-fly to both replication strands, starkly contrasting the strand asymmetric tolerance of bulky UV-induced adducts5. The accumulation of multiple distinct mutations at the site of persistent lesions provides the means to quantify the relative efficiency of repair processes genome wide and at single-base resolution. At multiple scales, we show DNA damage-induced mutations are largely shaped by the influence of DNA accessibility on repair efficiency, rather than gradients of DNA damage. Finally, we reveal specific genomic conditions that can actively drive oncogenic mutagenesis by corrupting the fidelity of nucleotide excision repair. These results provide insight into how strand-asymmetric mechanisms underlie the formation, tolerance and repair of DNA damage, thereby shaping cancer genome evolution

Identification of seven novel loci associated with amino acid levels using single-variant and gene-based tests in 8545 Finnish men from the METSIM study.

Comprehensive metabolite profiling captures many highly heritable traits, including amino acid levels, which are potentially sensitive biomarkers for disease pathogenesis. To better understand the contribution of genetic variation to amino acid levels, we performed single variant and gene-based tests of association between nine serum amino acids (alanine, glutamine, glycine, histidine, isoleucine, leucine, phenylalanine, tyrosine, and valine) and 16.6 million genotyped and imputed variants in 8545 non-diabetic Finnish men from the METabolic Syndrome In Men (METSIM) study with replication in Northern Finland Birth Cohort (NFBC1966). We identified five novel loci associated with amino acid levels (P = < 5×10-8): LOC157273/PPP1R3B with glycine (rs9987289, P = 2.3×10-26); ZFHX3 (chr16:73326579, minor allele frequency (MAF) = 0.42%, P = 3.6×10-9), LIPC (rs10468017, P = 1.5×10-8), and WWOX (rs9937914, P = 3.8×10-8) with alanine; and TRIB1 with tyrosine (rs28601761, P = 8×10-9). Gene-based tests identified two novel genes harboring missense variants of MAF <1% that show aggregate association with amino acid levels: PYCR1 with glycine (Pgene = 1.5×10-6) and BCAT2 with valine (Pgene = 7.4×10-7); neither gene was implicated by single variant association tests. These findings are among the first applications of gene-based tests to identify new loci for amino acid levels. In addition to the seven novel gene associations, we identified five independent signals at established amino acid loci, including two rare variant signals at GLDC (rs138640017, MAF=0.95%, Pconditional = 5.8×10-40) with glycine levels and HAL (rs141635447, MAF = 0.46%, Pconditional = 9.4×10-11) with histidine levels. Examination of all single variant association results in our data revealed a strong inverse relationship between effect size and MAF (Ptrend<0.001). These novel signals provide further insight into the molecular mechanisms of amino acid metabolism and potentially, their perturbations in disease

Identification of seven novel loci associated with amino acid levels using single-variant and gene-based tests in 8545 Finnish men from the METSIM study

Abstract Comprehensive metabolite profiling captures many highly heritable traits, including amino acid levels, which are potentially sensitive biomarkers for disease pathogenesis. To better understand the contribution of genetic variation to amino acid levels, we performed single variant and gene-based tests of association between nine serum amino acids (alanine, glutamine, glycine, histidine, isoleucine, leucine, phenylalanine, tyrosine, and valine) and 16.6 million genotyped and imputed variants in 8545 non-diabetic Finnish men from the METabolic Syndrome In Men (METSIM) study with replication in Northern Finland Birth Cohort (NFBC1966). We identified five novel loci associated with amino acid levels (P = &lt; 5×10−8): LOC157273/PPP1R3B with glycine (rs9987289, P = 2.3×10−26); ZFHX3 (chr16:73326579, minor allele frequency (MAF) = 0.42%, P = 3.6×10−9), LIPC (rs10468017, P = 1.5×10−8), and WWOX (rs9937914, P = 3.8×10−8) with alanine; and TRIB1 with tyrosine (rs28601761, P = 8×10−9). Gene-based tests identified two novel genes harboring missense variants of MAF &lt; 1% that show aggregate association with amino acid levels: PYCR1 with glycine (Pgene = 1.5×10−6) and BCAT2 with valine (Pgene = 7.4×10−7); neither gene was implicated by single variant association tests. These findings are among the first applications of gene-based tests to identify new loci for amino acid levels. In addition to the seven novel gene associations, we identified five independent signals at established amino acid loci, including two rare variant signals at GLDC (rs138640017, MAF=0.95%, Pconditional = 5.8×10−40) with glycine levels and HAL (rs141635447, MAF = 0.46%, Pconditional = 9.4×10−11) with histidine levels. Examination of all single variant association results in our data revealed a strong inverse relationship between effect size and MAF (Ptrend&lt;0.001). These novel signals provide further insight into the molecular mechanisms of amino acid metabolism and potentially, their perturbations in disease