Integrative epigenomic and high-throughput functional enhancer profiling reveals determinants of enhancer heterogeneity in gastric cancer

Taotao Sheng, Shamaine Wei Ting Ho, Wen Fong Ooi, Chang Xu, Manjie Xing, Nisha Padmanabhan, Kie Kyon Huang, Lijia Ma, Mohana Ray, Yu Amanda Guo, Ngak Leng Sim, Chukwuemeka George Anene-Nzelu, Mei Mei Chang, Milad Razavi-Mohseni, Michael A. Beer, Roger Sik Yin Foo, Raghav Sundar, Yiong Huak Chan, Angie Lay Keng Tan, Xuewen OngAnders Jacobsen Skanderup, Kevin P. White, Sudhakar Jha, Patrick Tan

Research output: Contribution to journalArticlepeer-review


Background: Enhancers are distal cis-regulatory elements required for cell-specific gene expression and cell fate determination. In cancer, enhancer variation has been proposed as a major cause of inter-patient heterogeneity—however, most predicted enhancer regions remain to be functionally tested. Methods: We analyzed 132 epigenomic histone modification profiles of 18 primary gastric cancer (GC) samples, 18 normal gastric tissues, and 28 GC cell lines using Nano-ChIP-seq technology. We applied Capture-based Self-Transcribing Active Regulatory Region sequencing (CapSTARR-seq) to assess functional enhancer activity. An Activity-by-contact (ABC) model was employed to explore the effects of histone acetylation and CapSTARR-seq levels on enhancer-promoter interactions. Results: We report a comprehensive catalog of 75,730 recurrent predicted enhancers, the majority of which are GC-associated in vivo (> 50,000) and associated with lower somatic mutation rates inferred by whole-genome sequencing. Applying CapSTARR-seq to the enhancer catalog, we observed significant correlations between CapSTARR-seq functional activity and H3K27ac/H3K4me1 levels. Super-enhancer regions exhibited increased CapSTARR-seq signals compared to regular enhancers, even when decoupled from native chromatin contexture. We show that combining histone modification and CapSTARR-seq functional enhancer data improves the prediction of enhancer-promoter interactions and pinpointing of germline single nucleotide polymorphisms (SNPs), somatic copy number alterations (SCNAs), and trans-acting TFs involved in GC expression. We identified cancer-relevant genes (ING1, ARL4C) whose expression between patients is influenced by enhancer differences in genomic copy number and germline SNPs, and HNF4α as a master trans-acting factor associated with GC enhancer heterogeneity. Conclusions: Our results indicate that combining histone modification and functional assay data may provide a more accurate metric to assess enhancer activity than either platform individually, providing insights into the relative contribution of genetic (cis) and regulatory (trans) mechanisms to GC enhancer functional heterogeneity.

Original languageEnglish (US)
Article number158
JournalGenome Medicine
Issue number1
StatePublished - Dec 2021
Externally publishedYes


  • CapSTARR-seq
  • Enhancer heterogeneity
  • Enhancer landscape
  • Enhancer-promoter interactions
  • Gastric cancer

ASJC Scopus subject areas

  • Molecular Medicine
  • Molecular Biology
  • Genetics
  • Genetics(clinical)


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