A 584 bp deletion in CTRB2 inhibits chymotrypsin B2 activity and secretion and confers risk of pancreatic cancer

Ashley Jermusyk, Jun Zhong, Katelyn E Connelly, Naomi Gordon, Sumeth Perera, Ehssan Abdolalizadeh, Tongwu Zhang, Aidan O'Brien, Jason W Hoskins, Irene Collins, Daina Eiser, Chen Yuan, Harvey A Risch, Eric J Jacobs, Donghui Li, Mengmeng Du, Rachael Z Stolzenberg-Solomon, Alison P Klein, Jill P Smith, Brian M WolpinStephen J Chanock, Jianxin Shi, Gloria M Petersen, Christopher J Westlake, Laufey T Amundadottir, PanScan Consortium

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)

Abstract

Genome-wide association studies (GWASs) have discovered 20 risk loci in the human genome where germline variants associate with risk of pancreatic ductal adenocarcinoma (PDAC) in populations of European ancestry. Here, we fine-mapped one such locus on chr16q23.1 (rs72802365, p = 2.51 × 10-17, OR = 1.36, 95% CI = 1.31-1.40) and identified colocalization (PP = 0.87) with aberrant exon 5-7 CTRB2 splicing in pancreatic tissues (pGTEx = 1.40 × 10-69, βGTEx = 1.99; pLTG = 1.02 × 10-30, βLTG = 1.99). Imputation of a 584 bp structural variant overlapping exon 6 of CTRB2 into the GWAS datasets resulted in a highly significant association with pancreatic cancer risk (p = 2.83 × 10-16, OR = 1.36, 95% CI = 1.31-1.42), indicating that it may underlie this signal. Exon skipping attributable to the deletion (risk) allele introduces a premature stop codon in exon 7 of CTRB2, yielding a truncated chymotrypsinogen B2 protein that lacks chymotrypsin activity, is poorly secreted, and accumulates intracellularly in the endoplasmic reticulum (ER). We propose that intracellular accumulation of a nonfunctional chymotrypsinogen B2 protein leads to ER stress and pancreatic inflammation, which may explain the increased pancreatic cancer risk in carriers of CTRB2 exon 6 deletion alleles.

Original languageEnglish
Pages (from-to)1852-1865
Number of pages14
JournalAmerican Journal of Human Genetics
Volume108
Issue number10
Early online date23 Sept 2021
DOIs
Publication statusPublished - 07 Oct 2021
Externally publishedYes

Bibliographical note

Published by Elsevier Inc.

Keywords

  • Case-Control Studies
  • Chymotrypsin/antagonists & inhibitors
  • Genome-Wide Association Study
  • Genotype
  • Humans
  • Pancreatic Neoplasms/etiology
  • Polymorphism, Single Nucleotide
  • Quantitative Trait Loci
  • Sequence Deletion

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