Project description:The aim of the study is to identify KMT9α target genes in AOM/DSS tumour organoids, APK and APKK organoids, patient derived CRC organoids, AOM/DSS mouse tumours and normal mouse colon
Project description:Novel treatment modalities are imperative for the challenging management of muscle-invasive and metastatic BC to improve patient survival rates. The recently identified lysine methyltransferase (KMT) 9, an obligate heterodimer composed of KMT9α and KMT9β, regulates the growth of various types of tumors such as prostate, lung and colon cancer. While overexpression of KMT9α was previously observed to be associated with aggressive basal-like MIBC in an analysis of patients’ tissue samples, a potential functional role of KMT9 in this type of cancer has not been investigated to date. In this study, we show that KMT9 regulates proliferation and migration of various MIBC cell lines with different genetic mutations. KMT9α depletion results in differential expression of genes involved in the regulation of the cell cycle, cell adhesion and migration. Reduced cell proliferation upon KMT9α depletion is also observed in Pten/Trp53 knockout bladder tumor organoids, which cannot be rescued with an enzymatically inactive KMT9α mutant. In accordance with the idea that the catalytic activity of KMT9 is required for the control of cellular processes in MIBC, a recently developed small molecule inhibitor of KMT9 (KMI169) also impairs cancer cell proliferation. Since KMT9α depletion also restricts the growth of xenografts in mice, our data suggest that KMT9 is an actionable novel therapeutic target for the treatment of MIBC.
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.