Project description:Oncogenic KRAS mutations are a key driver for initiation and progression in non-small-cell lung cancer (NSCLC). However, how post-translational modifications (PTMs) of KRAS, especially methylation, modify KRAS activity remain largely unclear. Here, we show that SET domain containing histone lysine methyltransferase 7 (SETD7) interacts with KRAS and methylates KRAS at lysines 182 and 184. SETD7-mediated methylation of KRAS leads to degradation of KRAS and attenuation of the RAS/MEK/ERK signaling cascade, endowing SETD7 with a potent tumor-suppressive role in NSCLC, both in vitro and in vivo. Mechanistically, RABGEF1, a ubiquitin E3 ligase of KRAS, was recruited and promoted KRAS degradation in a K182/K184 methylation-dependent manner. Notably, SETD7 is inversely correlated with KRAS at the protein level in clinical NSCLC tissues. Low SETD7 or RABGEF1 expression is associated with poor prognosis in lung adenocarcinoma patients. Altogether, our results elucidate a tumor-suppressive function of SETD7 that operates via modulating KRAS methylation and degradation.
Project description:Coordinated epigenome alteration is fundamental for cardiac development. However, the precise mechanisms by which epigenetic modifying enzymes regulate cardiac development are still unclear. Here we identify SET domain containing protein 7 (SETD7) as a key regulator of cardiac differentiation. ChIP-seq reveals that SETD7 has distinct groups of target genes and regulates its stage-specific expression during cardiomyocyte differentiation, which is crucial for lineage commitment. We find SETD7 associates with stage-specific co-factors, such as SWI/SNF chromatin remodeling factors during mesodermal formation and transcription factor NKX2-5 in cardiac progenitor differentiation. Cross-analysis of epigenetic modifications shows that SETD7 recognizes and binds with active histone marker H3K36 methylation on gene-body region of its target genes. We further demonstrate SETD7 is required for functional properties of terminally differentiated cardiomyocytes. Together, our results suggest unidentified roles of SETD7 in cardiac lineage commitment and provide new insights into the crosstalk between epigenetic dynamics and epigenetic modifying enzymes.
Project description:We recently reported that in prostate cancer LSD1 can demethylate the lysine 270 of FOXA1 to stabilize FOXA1 chromatin binding and thus can enhance the activities of AR and other transcription factors that require FOXA1 as a pioneer factor. However, the methyltransferase that can methylate FOXA1 and negatively regulate the LSD1-FOXA1 oncogenic axis remains unknown. SETD7 is initially identified as a transcriptional activator through methylating histone 3 lysine 4 but can also function as a methyltransferase on other non-histone substrates. However, its function in PCa remains poorly understood. In this study, we found that SETD7 confers tumor suppressor activity in PCa cells and that loss of SETD7 expression is significantly associated with PCa progression and tumor aggressiveness. Mechanistically, we found that SETD7 primarily acts as a transcriptional repressor in CRPC cells by functioning as a methyltransferase of FOXA1-K270 to disrupt FOXA1-mediated transcription. Overall, our study provides novel mechanistic insights into the tumor-suppressive and transcriptional repression activities of SETD7 in mediating PCa progression and therapy resistance.
Project description:The differentiation of human pluripotent stem cells into definitive endoderm (DE), a pivotal event in embryonic development, remains incompletely elucidated with respect to its epigenetic control. Here, we identified SETD7, a histone H3K4 monomethyltransferase (H3K4me1), as dynamically upregulated during DE specification, with its expression correlating strongly with the key lineage marker SOX17. Genetic knockdown of SETD7 impaired DE formation, as evidenced by reduced expression of DE markers and disruption of APLNR-mediated PI3K/AKT/mTOR signaling—a phenotypic defect recapitulated by pharmacological inhibition of APLNR. Mechanistically, SETD7 facilitates H3K4me1 deposition at enhancer regions of APLNR, thereby promoting its transcriptional activation. Our findings unveil an epigenetic-regulatory axis wherein SETD7-mediated enhancer priming drives APLNR expression, ultimately activating the PI3K/AKT/mTOR cascade to promote endodermal commitment. Through an integrated approach incorporating doxycycline-inducible SETD7 knockdown in hESCs, pathway-specific pharmacology, ChIP-qPCR, and 3D organoid modeling, we decipher the spatiotemporal regulatory network governed by SETD7 during DE specification. This study highlights the critical crosstalk between histone modification landscapes and signal transduction during cell fate determination and establishes a novel strategy for manipulating differentiation trajectories.
Project description:Global proteomics of Multiple Myeloma cell line MM.1S treated with pomalidomide or cyclic imide dipeptides for 10 h. The samples were labeled with TMT-16pro.
Project description:To determine the transcriptional impact of SETD7,MLL1 silencing in CRPC cells, we performed an RNA-seq analysis in those 22Rv1 stable cell lines (under hormone-depleted conditions)
