Project description:Posttranslational modifications of histones such as methylation regulate chromatin structure and gene expression. Methylation of histone lysine residues is generally performed by SET domain methyltransferases. Here, we identify the heterodimeric C21orf127/TRMT112 complex as a specific histone methyltransferase. Assembly of the seven-b-strand protein C21orf127 (also named Hemk2, N6amt1 or PrmC) with TRMT112 is essential to form an active enzyme, hereafter named KMT9 that writes the histone mark H4K12me1 in vitro and in vivo. The H4K12me1 mark is enriched at promoters of KMT9 target genes and co-localises with the active histone mark H4K12ac. By controlling expression of genes involved in energy metabolism, KMT9 regulates oxidative phosphorylation in androgen receptor-dependent and -independent prostate tumour cells. Importantly, KMT9 depletion severely affects proliferation of castration and enzalutamide-resistant prostate cancer cells and xenograft tumours. Together, our data link the writing of the H4K12me1 histone mark by KMT9 with KMT9-dependent gene expression, which in consequence regulates energy metabolism and proliferation. KMT9 executes these functions independently of androgen receptor and androgen signalling thus, providing a promising paradigm for the treatment of castration resistant prostate cancer.
Project description:The PDGF and mTOR pathways are clinically relevant therapeutic targets in clear cell renal cell carcinoma (ccRCC), but the molecular mechanisms that lead to their activation has remained poorly understood. By chromatin and transcriptomic profiling and functional analysis we have identified Kruppel like factor 6 (KLF6), a transcription factor of the zinc-finger family, as a critical regulator of the PDGF-mTOR axis in ccRCC. KLF6 expression is supported by one of the strongest super enhancers in ccRCC cells. Inhibition of KLF6 in several ccRCC cell lines impaired cell proliferation in vitro and in vivo and reduced metastatic lung colonization. KLF6 depletion led to downregulation of lipid homeostasis pathways downstream of SREBF1 and SREBF2, suggesting a role for KLF6 as a regulator of mTOR. We find that KLF6 modulates mTORC1 activity in ccRCC via transcriptionally regulating the expression of PDGFB, an activator of the PIK3-AKT-mTOR signalling pathway. Targeting PDGFB in ccRCC inhibited mTORC1, and supplementing KLF6-depleted cells with recombinant PDGFB rescued mTORC1 activity. Our data suggest that a robust super enhancer that integrates signals from multiple pathways, including the ccRCC-initiating VHL-HIF2A pathway, supports an autocrine PDGFB-dependent signalling loop that promotes mTOR activity in ccRCC. These results suggest the possibility that combining low dose PDGFR and mTOR inhibition could be a viable therapeutic strategy for ccRCC.
Project description:Isoniazid (INH) is the first-line anti-tuberculosis drug used for nearly seventy years. Metabolites of INH showed hepatotoxicity in human and tumorigenicity in rodents. However, mechanism underlying the side effects of INH is elusive. Histone acylation is known to be modulated by intracellular metabolites. Here, we report INH and its metabolites induces a novel post-translational modification (PTM) on histones, the lysine isonicotinylation (Kinic), also called 4-picolinylation, in cells and mice. INH functions as a donor to promote biosynthesis of isonicotinyl-CoA that is used for a co-factor of intracellular isonicotinylation reaction. Twenty-six isonicotinylation sites were identified on histones in HepG2 cells by mass spectrometry. Acetyltransferases CREB-binding protein (CBP) and P300 were found to catalyze histone Kinic, whilst histone deacetylase HDAC3 functions as a deisonicotinylase. MNase sensitivity assay and RNA-seq analysis showed that histone Kinic relaxes chromatin structure and promotes gene transcription. Importantly, INH-mediated histone Kinic upregulates PIK3R1 gene expression and activates PI3K/Akt/mTOR signaling pathway in liver cancer cells, linking INH to the tumorigenicity in liver. Further, Kinic was found increased in liver cancer patients with concomitant raised PIK3R1 protein level. In addition, histone Kinic also affects TNF and GABAergic synapse signaling pathways that are closely related to INH-caused side effects. Taken together, we demonstrated that lysine isonicotinylation represents the first histone acylation mark with the pyridine ring that may arise broad biological effects. Therefore, INH-induced isonicotinylation is likely a mechanism accounting for side effects in patients who taking long-term INH for anti-tuberculosis therapy and this modification may also increase cancer risk in human.
Project description:We identified and characterized a previously undescribed histone mark, lysine benzoylation. This histone mark could be modulated by sodium benzoate (SB), an FDA-approved drug and a widely used chemical food preservative, via generation of benzoyl CoA. By ChIP-seq and RNA-seq analysis, we demonstrate that histone lysine benzoylation marks are involved in regulation of gene expression and associated with diverse biological processes. This study therefore reveals a new type of physiological relevant histone mark and identifies non-conical functions of a widely used chemical food preservative.
Project description:We identified and characterized a previously undescribed histone mark, lysine benzoylation. This histone mark could be modulated by sodium benzoate (SB), an FDA-approved drug and a widely used chemical food preservative, via generation of benzoyl CoA. By ChIP-seq and RNA-seq analysis, we demonstrate that histone lysine benzoylation marks are involved in regulation of gene expression and associated with diverse biological processes. This study therefore reveals a new type of physiological relevant histone mark and identifies non-conical functions of a widely used chemical food preservative.
Project description:This SuperSeries is composed of the SubSeries listed below. Posttranslational modifications of histones such as methylation regulate chromatin structure and gene expression. Methylation of histone lysine residues is generally performed by SET domain methyltransferases. Here, we identify the heterodimeric C21orf127/TRMT112 complex as a histone methyltransferase. Assembly of the seven-b-strand protein C21orf127 (also named Hemk2, N6amt1 or PrmC) with TRMT112 is essential to form an active enzyme, hereafter named KMT9 that writes the histone mark H4K12me1 in vitro and in vivo. We characterized the recognition mode of H4K12 by KMT9 that is formed by the assembly of KMT9a with KMT9b by solving the co-crystal structure. Genome-wide analyses revealed KMT9 and H4K12me1 enrichment at promoters of KMT9 target genes. By controlling expression of genes involved in cell cycle regulation, KMT9 regulates proliferation of androgen receptor-dependent and -independent prostate tumour cells. Importantly, KMT9 depletion severely affects proliferation of castration- and enzalutamide-resistant prostate cancer cells and xenograft tumours. Together, our data link the writing of the H4K12me1 histone mark by KMT9 with KMT9-dependent gene expression, which in consequence regulates cell cycle and proliferation. KMT9 executes these functions independently of androgen receptor and androgen signalling thus, providing a promising paradigm for the treatment of castration resistant prostate cancer.