Targeting Type I arginine methyltransferase PRMT1 promotes the T cell mediated antitumor immune response
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE162676 | GEO | 2022/03/01
REPOSITORIES: GEO
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Project description:Protein arginine methyltransferases (PRMTs) are required for the regulation of RNA processing factors. Type I PRMT enzymes catalyze mono- and asymmetric dimethylation; Type II enzymes catalyze mono- and symmetric dimethylation. To understand the specific mechanisms of PRMT activity in splicing regulation, we inhibited Type I and II PRMTs and probed their transcriptomic consequences. Using the newly developed Splicing Kinetics and Transcript Elongation Rates by Sequencing (SKaTER-seq) method, analysis of co-transcriptional splicing demonstrated that PRMT inhibition resulted in altered splicing rates. Surprisingly, co-transcriptional splicing kinetics did not correlate with final changes in splicing of polyadenylated RNA. This was particularly true for retained introns (RI). By using actinomycin D to inhibit ongoing transcription, we determined that PRMTs post-transcriptionally regulate RI. Subsequent proteomic analysis of both PRMT-inhibited chromatin and chromatin-associated polyadenylated RNA identified altered binding of many proteins, including the Type I substrate, CHTOP, and the Type II substrate, SmB. Targeted mutagenesis of all methylarginine sites in SmD3, SmB, and SmD1 recapitulated splicing changes seen with Type II PRMT inhibition, without disrupting snRNP assembly. Similarly, mutagenesis of all methylarginine sites in CHTOP recapitulated the splicing changes seen with Type I PRMT inhibition. Examination of subcellular fractions further revealed that RI were enriched in the nucleoplasm and chromatin. Together, these data demonstrate that, through Sm and CHTOP arginine methylation, PRMTs regulate the post-transcriptional processing of nuclear, detained introns.
2022-01-08 | GSE163421 | GEO
Project description:Aberrant protein arginine methylation has been observed in multiple cancer types, making it an attractive drug target. Proteins can undergo asymmetric arginine methylation by type I protein arginine methyltransferases (PRMTs), predominately by PRMT1 and to a lesser extent PRMT4, or symmetric arginine methylation by type II PRMTs, predominately PRMT5. Here, we performed targeted proteomics following inhibition of PRMT1, PRMT4, and PRMT5 across cancer cell lines. We found that inhibition of both type I and type II PRMTs suppressed levels of total and phosphorylated ATR protein in cancer cell lines, and down-regulated expression of the ATR gene. Loss of ATR from PRMT inhibition resulted in defective DNA replication stress response activation in following exogenous replication stress. Since PARP inhibitors are known to induce replication stress, we next combined PRMT inhibition with PARP inhibition and found inhibition of PRMT1 or PRMT5 greatly exacerbated PARP inhibitor induced DNA damage. Based on this observation, we assessed the combination of PARP and PRMT inhibition in a panel of cell lines. While inhibition of both type I and type II PRMTs were synergistic with PARP inhibition in both cells with intact and deficient homologous recombination, type I PRMT inhibition resulted in higher toxicity in non-malignant cells. Therefore, we validated the synergy of combined PARP/PRMT5 inhibition in primary patient-derived organoids. Finally, we demonstrate that the combination of PARP and PRMT5 inhibition improves overall survival in both BRCA-mutant and wild-type patient-derived xenograft models without any detectable hematological toxicities typically associated with PARPi combination therapies. Taken together, these results demonstrate that PRMT5 inhibition may be a well-tolerated approach to improve tumor sensitivity to PARP inhibition. .
2023-10-26 | GSE246325 | GEO
Project description:Type I Protein Arginine Methyltransferases (PRMTs) catalyze asymmetric dimethylation of arginine (ADMA) residues on numerous protein substrates to modulate their activity. Type I PRMTs and many of their substrates have been implicated in human cancers, suggesting that inhibiting Type I PRMT activity offers a tractable approach for therapeutic intervention. The current report describes GSK3368715 (EPZ019997), a potent, reversible Type I PRMT inhibitor with anti-tumor activity against human cancer cells both in vitro and in vivo. GSK3368715 reduces ADMA on numerous substrates and concomitantly increases monomethyl (MMA) and symmetric dimethyl arginine (SDMA) levels. Inhibition of PRMT5, the major type II PRMT, attenuates this induction and produces synergistic antiproliferative effects in combination with GSK3368715 in cancer cells. PRMT5 activity is inhibited by 2-methylthioadenosine (MTA), a naturally occurring metabolite that accumulates in tumor cells deficient for the enzyme Methylthioadenosine Phosphorylase (MTAP). MTAP deletion in cancer cell lines correlates with sensitivity to GSK3368715, indicating a sufficient degree of PRMT5 inhibition from MTA accumulation to achieve a tumor cell-intrinsic combination. These data provide the rationale to explore MTAP status as a biomarker strategy for patient selection to maximize the anti-tumor activity of GSK3368715.
2019-08-15 | GSE126651 | GEO
Project description:Since many proteins involved in splicing regulation were identified as PRMT substrates, we examined the impact of PRMT inhibition on alternative RNA splicing. We achieved effective gene silence with shRNAs in six different PRMTs and examined their effect on splicing using RNA-seq.
2022-06-30 | GSE153143 | GEO
Project description:Type I Protein Arginine Methyltransferases (PRMTs) catalyze asymmetric dimethylation of arginine residues on numerous proteins. Type I PRMTs and their substrates have been implicated in human cancers, suggesting that inhibiting Type I PRMT activity offers a tractable approach for therapeutic intervention. This dataset contains results from immunoproteomic studies enriching for monomethylated, asymmetrically, and symmetrically dimethylated arginines in cancer cell lines treated with the Type I PRMT inhibitor, GSK3368712.
2019-09-10 | PXD012747 | Pride
Project description:We functionally characterized the five predicted PRMTs in Leishmania braziliensis by gene knockout and endogenous protein HA tagging using CRISPR/Cas9 gene editing. We report that R-methylation profiles vary among Leishmania species and across L. braziliensis lifecycle stages, with the peak PRMT expression occurring in promastigotes. A list of PRMT-interacting proteins was obtained in a single coimmunoprecipitation assay using HA-tagged PRMTs, suggesting a network of putative targets of PRMTs and cooperation between the R-methylation writers. Knockout of each L. braziliensis PRMT led to significant changes in global arginine methylation patterns without affecting cell viability. Deletion of either PRMT1 or PRMT3 disrupted most type I PRMT activity, resulting in a global increase in monomethyl arginine levels. Using anti-MMA antibodies, we performed an IP experiment to identify MMA proteins in the parental line, single PRMT1 knockout, PRMT1/PRMT7 double knockout and PRMT1-Addback parasites. The results indicate that R-methylation is modulated across lifecycle stages in L. braziliensis and show possible functional overlap and cooperation among the different PRMTs in targeting proteins. Overall, our data suggest important regulatory roles of these proteins throughout the L. braziliensis life cycle, showing that arginine methylation is important for parasite-host cell interactions. Linked publication: https://doi.org/10.1101/2021.09.22.461376.
2022-03-03 | PXD031057 | Pride
Project description:Cancer-associated mutations in RNA splicing factors commonly occur in myeloid and lymphoid leukemias as well as a variety of solid tumors and confer dependence on wild-type (WT) splicing. These observations have led to clinical efforts to directly inhibit the spliceosome in patients with refractory leukemias. Here we identify that inhibiting symmetric (SDMA) or asymmetric dimethyl arginine methylation (ADMA), mediated by PRMT5 and type I protein arginine methyltransferases (PRMTs) respectively, reduces splicing fidelity and results in strong preferential killing of spliceosomal mutant leukemias over WT counterparts. Consistent with this, proteomic analyses identified RNA binding proteins and splicing factors as the most enriched PRMT5 and/or PRMT Type I substrates in leukemia. Accordingly, combined PRMT5/type I PRMT inhibition resulted in synergistic cell killing and pronounced effects on splicing compared with inhibiting either enzymatic activity alone. These data identify genetic subsets of cancer most likely to respond to PRMT inhibition and a mechanistic basis for the therapeutic efficacy of PRMT inhibition in cancer.
2019-07-30 | PXD012007 | Pride
Project description:Arginine methylation is essential for both cellular viability and development and is also dysregulated in cancer. PRMTs catalyze the post translational monomethylation (Rme1/MMA, catalyzed by Type I-III), asymmetric (Rme2a/ADMA, Type I enzymes)-, or symmetric (Rme2s/SDMA, Type II enzymes) dimethylation of arginine. Despite many studies, a thorough integration of PRMT enzyme substrate determination and proteomic and transcriptomic consequences of inhibiting Type I and II PRMTs is lacking. To characterize cellular substrates for Type I (Rme2a) and Type II (Rme2s) PRMTs, human A549 lung adenocarcinoma cells were treated with either Type I (MS023) or Type II (GSK591) inhibitors. Using total proteome hydrolysis, we developed a new mass spectrometry approach to analyze total arginine and lysine content. We showed that Rme1 was a minor population (~0.1% of total arginine), Rme2a was highly abundant (~1.1%), and Rme2s was intermediate (~0.4%). While Rme2s was mostly eliminated by GSK591 treatment, total Rme1 and Rme2a were more resistant to perturbation. To quantitatively characterize substrate preferences of the major enzymes PRMT1, PRMT4(CARM1), and PRMT5, we used oriented peptide array libraries (OPAL) in methyltransferase assays. We demonstrated that while PRMT5 tolerates aspartic acid residues in the substrate, PRMT1 does not. Importantly, PRMT4 methylated previously uncharacterized hydrophobic motifs. To integrate our studies, we performed PTMScan on PRMT-inhibited A549 cells and enriched for methylated arginine containing tryptic peptides. For detection of highly charged peptides, a method to analyze the samples using electron transfer dissociation was developed. Proteomic analysis revealed distinct methylated species enriched in nuclear function, RNA-binding, intrinsically disordered domains, and liquid-liquid phase separation. Parallel studies with proteomics and RNA-Seq revealed distinct, but ontologically overlapping, consequences to PRMT inhibition. Overall, we demonstrate a wider PRMT substrate diversity and methylarginine functional consequence than previously shown.
2021-08-01 | GSE158625 | GEO
Project description:Protein arginine methylation, catalyzed by the protein arginine methyltransferase (PRMT) family, is recognized as a widespread post-translational modification (PTM) with implications in a plethora of biological processes in eukaryotes. PRMT proteins were classified into three types, type I, II and III, according to the final methyl-arginine products generated. Despite that thousands of substrates have been identified for Type I and II PRMTs, a full scope of arginine methylation catalyzed by the only type III PRMT, PRMT7, as well as its connection with that of type I and II PRMTs remain unknown, limiting our understanding of the network of arginine methylation and its functions in cells. In this study, global profiling of PRMT4 (type I), PRMT5 (type II) and PRMT7 (type III) substrates (also referred as methylome) revealed that PRMT7 methylated a GAR (glycine and arginine) motif similar as PRMT5, while PRMT4 uniquely methylated a motif in which proline was highly enriched. PRMT4, 5 and 7-methylome were all enriched with proteins functioning in mRNA splicing, and knockdown of PRMT4, 5 or 7 led to a global change of alternative splicing events, among which a cohort with implications in cancer development was co-regulated by all three PRMTs. PRMT4, 5 and 7-mediated arginine methylation on splicing factors such as hnRNPA1, though at different status, were shown to enhance RNA binding in general and participate in the regulation of PRMT4, 5 and 7 co-regulated alternative splicing events.The clinical significance of PRMT4, 5 and 7-mediated arginine methylation was underscored by the fact that these three PRMTs as well as hnRNPA1 arginine methylation were over-represented in multiple types of cancers, which were associated with aberrant gene alternative splicing. Consistently, silencing or pharmacological inhibition of PRMT4, 5 and 7 altered gene alternative splicing and suppressed cancer cell growth, and co-treatment exhibited synergistic effects. Taken together, our study provided an integrative view of substrates for the three types of PRMTs, revealing the important function of arginine methylation in RNA splicing and cancer.
2021-01-23 | GSE150040 | GEO
Project description:Immunotherapies have produced dramatic responses in reducing tumor growth and prolonging overall survival to unprecedented rates in melanoma, lung cancer, renal cancer and mismatch repair deficient colon cancer patients. Despite approvals for immune checkpoint inhibitors in a wide range of cancers, the majority of patients’ relapse following initial response to immunotherapy or fail to respond altogether. These failures can be attributed to an insufficient immune response against tumors and/or mechanisms co-opted by tumor cells to produce a suppressive tumor microenvironment. Therefore, identification of combination strategies to enhance the response rates of immunotherapies to a broader patient population are the current subject of intensive basic and clinical research. Type I PRMTs have been described as regulators of immune response pathways in several cell types by direct arginine methylation on specific substrates, as well as through indirect mechanisms. Recent work has suggested that arginine methylation may have a role in tumor immunity, yet these roles remain poorly understood. Using the skin cutaneous melanoma (SKCM) TCGA dataset, we show that increased expression of Type I PRMTs is associated with poor clinical response and decreased immune infiltration in melanoma patients. Through a series of preclinical tumor models, we demonstrate that inhibition of Type I PRMTs can increase hallmarks of an inflamed tumor microenvironment and sensitivity to inhibition of the PD-(L)1 signaling axis. Accordingly, Type I PRMT inhibition synergizes with immune checkpoint blockade to induce durable and effective antitumor responses in an array of immunocompetent tumor models. These data provide a rationale to combine Type I PRMT inhibitors with checkpoint blockade to maximize clinical benefit in cancer patients.
2022-11-01 | GSE161908 | GEO