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PRMT1 Promotes Epigenetic Reprogramming Associated with Acquired Chemoresistance in Pancreatic Cancer

ABSTRACT: Pancreatic Ductal Adenocarcinoma (PDAC) is associated with extremely poor prognosis due to late diagnosis and therapeutic resistance. Here we show that PDAC cells undergo progressive reprogramming of the global epigenetic landscape during the process of acquiring chemoresistance. Through an epigenetic inhibitor screen, we identified Protein Arginine methyltransferase 1 (PRMT1) as a central driver of chemoresistance in PDAC. Genetic or pharmacological inhibition of PRMT1 impaired adaptive epigenetic reprogramming, sensitized PDAC cells to Gemcitabine and other commonly used chemo drugs, and delayed the development of acquired resistance both in vitro and in vivo. Mechanistically, we find that PRMT1, through its enzymatic activity, limits the accumulation of small bZIP transcription factor MAFF in the nucleus, and the assembly of chromatin-bound MAFF/BACH1 hetero-oligomeric complexes following Gemcitabine treatment. Genetic silencing of MAFF heightened the resistance of PDAC cells to Gemcitabine, and to combination of Gemcitabine and PRMT1 inhibitors. Cut&Tag chromatin profiling of H3K27Ac, MAFF and BACH1 suggests a pivotal role for MAFF/BACH1 in orchestrating global epigenetic reprogramming during the course of acquiring Gemcitabine resistance. Supporting the clinical relevance of our findings, predicted PRMT1 and MAFF/BACH1 genes signatures based on our Cut&Tag analysis were able to distinguish Gemcitabine-resistant from Gemcitabine-sensitive PDAC patient-derived xenografts according to expression changes induced by Gemcitabine. Together, our study reveals a novel epigenetic regulatory axis involving PRMT1 and MAFF/BACH1 that modulates Gemcitabine response, which could be potentially exploited for improving therapeutic response in advanced PDAC.

ORGANISM(S): Mus musculus

PROVIDER: GSE227129 | GEO | 2024/04/29

REPOSITORIES: GEO

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Project description:Chemoresistance to gemcitabine limits its clinical implementation for pancreatic ductal adenocarcinoma (PDAC). We previously generated an antibody drug conjugate (ADC) -like agent, EGFR/HER2 dual-targeting ligand-based lidamycin (DTLL), and studied the effect of DTLL combined with gemcitabine and the potential role of SMAD4 in the chemoresistance of PDAC. On the basis of SMAD4 profiles in in vitro and in vivo models, we investigated the antitumor effects of DTLL, gemcitabine and their combination, followed with mechanistic characterization. The results suggested that DTLL combination treatment with gemcitabine significantly repressed tumors with remarkably enhanced efficacy as compared to gemcitabine or DTLL alone given in either SMAD4-deficient/gemcitabine-resistant or SMAD4-sufficient/gemcitabine-sensitive cell line derived xenograft (CDX) and patient derived xenograft (PDX) tumors, respectively. Functional studies indicated that SMAD4 genetic status is responsible for SMAD4 protein level which determines different cellular susceptibility of PDAC. R100T mutation contributes to loss of SMAD4 protein and function with rapid protein degradation, leading to resistance to gemcitabine in PDAC cells. Moreover, DTLL significantly altered the protein half-life time and level of mutant and wild-type SMAD4 by inhibiting protein degradation at different velocities and distinctly changing the interaction of SMAD4 with TRIM33. Mechanism studies implied that DTLL combinational treatment might not only prevent from neoplastic proliferation via blockage of ATK/mTOR signaling and anti-apoptotic proteins (Bcl-2 and MCL1) mediated by impaired NF-B function in SMAD4-sufficient/gemcitabine-sensitive PDAC cells, but also restore the bioactivity of SMAD4 as a tumor suppressor to trigger its downstream NF-B-regulated signaling of cell apoptosis in SMAD4-deficient/gemcitabine-resistant tumors. In conclusion, SMAD4 is the key central mediator of not only the occurrence and development but also susceptibility in PDAC. DTLL sensitized gemcitabine efficacy via distinct action mechanisms based on SMAD4 profiles in SMAD4-sufficient/gemcitabine-sensitive and SMAD4-deficient/-resistant PDAC, respectively. Our findings provide insight into a rational SMAD4-directed precision treatment strategy and reveal a promising DTLL combination therapy to overcome chemoresistance in gemcitabine-resistant PDAC.

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PRMT1 Promotes Epigenetic Reprogramming Associated with Acquired Chemoresistance in Pancreatic Cancer

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