Project description:To further investigate the functional associations between PRMT1 and SMARCA4 and explore the biological significance of these interactions, we conducted expression profiling on the Agilent SurePrint G3 Human Gene Expression v3 (8*60K,Design ID:072363) using knockdown of PRMT1 or SMARCA4’s RNA in HCT116 cells.
Project description:To further investigate the functional associations between PRMT1 and SMARCA4 and explore the biological significance of these interactions, we conducted expression profiling on the Agilent SurePrint G3 Human Gene Expression v3 (8*60K,Design ID:072363) using knockdown of PRMT1 or SMARCA4’s RNA in HCT116 cells.
Project description:BackgroundAberrant changes in epigenetic mechanisms such as histone modifications play an important role in cancer progression. PRMT1 which triggers asymmetric dimethylation of histone H4 on arginine 3 (H4R3me2a) is upregulated in human colorectal cancer (CRC) and is essential for cell proliferation. However, how this dysregulated modification might contribute to malignant transitions of CRC remains poorly understood.MethodsIn this study, we integrated biochemical assays including protein interaction studies and chromatin immunoprecipitation (ChIP), cellular analysis including cell viability, proliferation, colony formation, and migration assays, clinical sample analysis, microarray experiments, and ChIP-Seq data to investigate the potential genomic recognition pattern of H4R3me2s in CRC cells and its effect on CRC progression.ResultsWe show that PRMT1 and SMARCA4, an ATPase subunit of the SWI/SNF chromatin remodeling complex, act cooperatively to promote colorectal cancer (CRC) progression. We find that SMARCA4 is a novel effector molecule of PRMT1-mediated H4R3me2a. Mechanistically, we show that H4R3me2a directly recruited SMARCA4 to promote the proliferative, colony-formative, and migratory abilities of CRC cells by enhancing EGFR signaling. We found that EGFR and TNS4 were major direct downstream transcriptional targets of PRMT1 and SMARCA4 in colon cells, and acted in a PRMT1 methyltransferase activity-dependent manner to promote CRC cell proliferation. In vivo, knockdown or inhibition of PRMT1 profoundly attenuated the growth of CRC cells in the C57BL/6 J-ApcMin/+ CRC mice model. Importantly, elevated expression of PRMT1 or SMARCA4 in CRC patients were positively correlated with expression of EGFR and TNS4, and CRC patients had shorter overall survival. These findings reveal a critical interplay between epigenetic and transcriptional control during CRC progression, suggesting that SMARCA4 is a novel key epigenetic modulator of CRC. Our findings thus highlight PRMT1/SMARCA4 inhibition as a potential therapeutic intervention strategy for CRC.ConclusionPRMT1-mediated H4R3me2a recruits SMARCA4, which promotes colorectal cancer progression by enhancing EGFR signaling.
Project description:Colorectal cancer (CRC) arises from multi-step accumulation of genetic and epigenetic mutations that deregulate intestinal homeostasis leading to neoplastic transformation and metastases. Constitutive activation of WNT signaling is considered the initial driver oncogenic event to which CRCs remain addicted, also in their most aggressive metastatic forms. WNT activation provokes an aberrant signaling that converges into the nucleus where transcription and chromatin-remodeling factors cooperate to regulate cell identity. This leads to deregulated proliferation, block of differentiation and evasion from cell death pathways. We found that the protein arginine methyltransferase 1 (PRMT1) is synthetic lethal with WNT oncogenic activation in both genetically-defined mouse models and patient-derived metastatic CRC organoids. WNT activation regulates the subcellular localization of PRMT1, inducing its complete nuclear translocation. This makes CRCs specifically dependent on PRMT1 enzymatic activity to sustain WNT-dependent proliferation regardless of the mutational landscape carried by distinct patients. Together these data uncover a new molecular crosstalk between WNT activation and PRMT1 activity and place PRMT1 inhibition as a potential strategy to counteract CRC addiction to WNT oncogenic activation.
Project description:PRMT1 is thought to be responsible for the majority of PRMT activity in Toxoplasma gondii, but its exact function is unknown. We generated T. gondii mutants lacking PRMT1 (∆prmt1) by deletion of the PRMT1 gene. ∆prmt1 parasites exhibit morphological defects during cell division and grow slowly, and this phenotype reverses in the complemented strain ∆prmt::PRMT1mRFP. PRMT1 localizes primarily in the cytoplasm with enrichment at the centrosome, and the strain lacking PRMT1 is unable to segregate progeny accurately. Unlike wild-type and complemented parasites, ∆prmt1 parasites have abnormal daughter buds, perturbed centrosome stoichiometry, and loss of synchronous replication. Whole genome expression profiling demonstrated differences in expression of cell cycle regulated genes in ∆prmt1 relative to the complemented ∆prmt1::PRMT1mRFP and parental wild-type strains, but these changes did not correlate with a specific block in cell cycle. Although PRMT1’s primary biological function was previously proposed to be methylation of histones, our genetic studies suggest that the most critical function of PRMT1 is within the centrosome as a regulator of daughter cell counting to assure the proper replication of the parasite. RNA samples were isolated in triplicates from RH-hxgprt parent strain (W), PRMT1 knockout (K) strain and PRMT1 knockout strain complemented with RFP-tagged PRMT1 protein (C). Parasites were grown for 32h at 37C. Samples were hybridized to the Toxoplasma gondii Affymetrix microarray (ToxoGeneChip: http://ancillary.toxodb.org/docs/Array-Tutorial.html). Hybridization data was preprocessed with Robust Multi-array Average (RMA) and normalized using per chip and per gene median polishing and analyzed using the software package GeneSpring GX (Agilent Technologies).
Project description:Genomic studies have demonstrated a high frequency of genetic alterations in components of the SWI/SNF complex including the core subunit SMARCA4. However, the mechanisms of tumorigenesis driven by SMARCA4 mutations, particularly in colorectal cancer (CRC), remain largely unknown. In this study, we identified a specific, hotspot mutation in SMARCA4 (c. 3721C>T) which results in a conversion from arginine to tryptophan at residue 1157 (R1157W) in human CRC tissues associated with higher-grade tumors and controls CRC progression. Mechanistically, we found that the SMARCA4R1157W mutation facilitated its recruitment to PRMT1-mediated H4R3me2a (asymmetric dimethylation of Arg 3 in histone H4) and enhanced the ATPase activity of SWI/SNF complex to remodel chromatin in CRC cells. We further showed that the SMARCA4R1157W mutant reinforced the transcriptional expression of EGFR and TNS4 to promote the proliferation of CRC cells and patient-derived tumor organoids. Importantly, we demonstrated that SMARCA4R1157W CRC cells and mutant cell-derived xenografts were more sensitive to the combined inhibition of PRMT1 and SMARCA4 which act synergistically to suppress cell proliferation. Together, our findings show that SMARCA4-R1157W is a critical activating mutation, which accelerates CRC progression through facilitating chromatin recruitment and remodeling. Our results suggest a potential precision therapeutic strategy for the treatment of CRC patients carrying the SMARCA4R1157W mutation.
Project description:Transcriptional deregulation plays a major role in acute myeloid leukemia, identification of epigenetic modifying enzymes essential for the maintenance of oncogenic transcription programs holds the key to better understanding the biology and designing effective therapeutic strategies for the disease. Here we provide experimental evidence showing the functional involvement and therapeutic potentials of targeting PRMT1 with H4R3 methyltransferase activity in various MLL and non-MLL leukemias. PRMT1 is necessary but not sufficient for leukemic transformation, which requires co-recruitment of KDM4C with H3K9 demethylase activity by chimeric transcription factors to mediate epigenetic reprogramming. Inhibition of KDM4C/PRMT1 suppresses transcription and transformation ability of MLL fusions and MOZ-TIF2, revealing a novel and targetable epigenetic circuitry mediated by PRMT1 and KDM4C in acute leukemia.