Targeted CRISPR screening identifies PRMT5 as synthetic lethality combinatorial target with gemcitabine in pancreatic cancer cells

Xiaolong Wei*, Jiekun Yang, Sara J. Adair, Harun Ozturk, Cem Kuscu, Kyung Yong Lee, William J. Kane, Patrick E. O’Hara, Denis Liu, Yusuf Mert Demirlenk, Alaa Hamdi Habieb, Ebru Yilmaz, Anindya Dutta, Todd W. Bauer, Mazhar Adli

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

Pancreatic ductal adenocarcinoma (PDAC) remains one of the most challenging cancers to treat. Due to the asymptomatic nature of the disease and lack of curative treatment modalities, the 5-y survival rate of PDAC patients is one of the lowest of any cancer type. The recurrent genetic alterations in PDAC are yet to be targeted. Therefore, identification of effective drug combinations is desperately needed. Here, we performed an in vivo CRISPR screen in an orthotopic patient-derived xenograft (PDX) model to identify gene targets whose inhibition creates synergistic tumor growth inhibition with gemcitabine (Gem), a first- or second-line chemotherapeutic agent for PDAC treatment. The approach revealed protein arginine methyltransferase gene 5 (PRMT5) as an effective druggable candidate whose inhibition creates synergistic vulnerability of PDAC cells to Gem. Genetic depletion and pharmacological inhibition indicate that loss of PRMT5 activity synergistically enhances Gem cytotoxicity due to the accumulation of excessive DNA damage. At the molecular level, we show that inhibition of PRMT5 results in RPA depletion and impaired homology-directed DNA repair (HDR) activity. The combination (Gem + PRMT5 inhibition) creates conditional lethality and synergistic

reduction of PDAC tumors in vivo. The findings demonstrate that unbiased genetic screenings combined with a clinically relevant model system is a practical approach in identifying synthetic lethal drug combinations for cancer treatment.

Original languageEnglish (US)
Pages (from-to)28068-28079
Number of pages12
JournalProceedings of the National Academy of Sciences of the United States of America
Volume117
Issue number45
DOIs
StatePublished - Nov 10 2020

Keywords

  • CRISPR screening | pancreatic cancer | cancer genomics and epigenomics | synthetic lethality | combinatorial drugs targets

ASJC Scopus subject areas

  • General

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