Dataset Information

STIM1 Mediates Calcium-dependent Epigenetic Reprogramming in Pancreatic Cancer [ChIPseq_siSTIM1_Thap]

ABSTRACT: We characterized Gemcitabine resistant pancreatic cancer tumors and show that the co-amplification of RRM1 and STIM1 confers novel and independent properties to gemcitabine resistant cells. The upregulation of RRM1 drives gemcitabine resistance, while the amplification of STIM1 leads to increased cytosolic calcium upon stress, eliciting ER stress resistance and NFAT activation.

ORGANISM(S): Homo sapiens

PROVIDER: GSE152120 | GEO | 2021/01/14

REPOSITORIES: GEO

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Project description:Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive malignancy characterized by a poor prognosis, and resistance to gemcitabine, a frontline chemotherapeutic agent, poses a significant challenge to effective treatment. Unraveling the molecular underpinnings of gemcitabine resistance is essential for devising novel therapeutic strategies. Here we derived gemcitabine-resistant and parental pancreatic cancer cell lines from KPC mouse models of PDAC. Employing a multi-omics approach, we integrated RNA-seq, ATAC-seq, and ChIP-seq analyses to characterize the genome-wide alterations in gene transcription, chromatin accessibility, histone modifications, and transcription factor (TF) binding in resistant cells. High-throughput chromatin conformation capture (Hi-C) was used to explore 3D chromatin remodeling. Our analyses identified differentially expressed genes (DEGs) critical for gemcitabine metabolism and resistance, notably Rrm1 and Cdadc1. We observed the upregulation of NF-kB, p53, and MAPK pathways, and the downregulation of mTORC1, MYC targets, and reactive oxygen species pathways. Differentially accessible regions (DARs) showed a significant positive correlation with the expression patterns of DEGs and histone mark H3K27 acetylation. Motif enrichment analyses revealed that TFs from the AP-1, Fox, and Hox families were significantly enriched at DARs, underscoring Foxa1 as a pivotal regulator of resistance-associated genes. We discovered that 3D chromatin reorganization, particularly the enhancement of enhancer-promoter interactions involving super-enhancer (SE) reprogramming mediated by Foxa1 and Ctcf/Smc3, drives the expression of critical resistance genes. Targeting Foxa1 or disrupting SE-associated transcription using JQ1, a bromodomain inhibitor, effectively inhibited resistant cell proliferation and enhanced gemcitabine sensitivity. In summary, this study elucidates the role of TF-mediated chromatin remodeling in gemcitabine resistance and suggests that targeting super-enhancers could be a promising therapeutic strategy to overcome resistance in PDAC, potentially revolutionizing drug therapy for this disease.