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Background The SETD2 tumor suppressor gene encodes a histone methyltransferase that safeguards transcription fidelity and genomic integrity via trimethylation of histone H3 lysine 36 (H3K36Me3). SETD2 loss of function has been observed in solid and hematologic malignancies. We have recently reported that most patients with advanced systemic mastocytosis (AdvSM) and some with indolent or smoldering SM display H3K36Me3 deficiency as a result of a reversible loss of SETD2 due to reduced protein stability. Methods Experiments were conducted in SETD2-proficient (ROSAKIT D816V) and -deficient (HMC-1.2) cell lines and in primary cells from patients with various SM subtypes. A short interfering RNA approach was used to silence SETD2 (in ROSAKIT D816V cells), MDM2 and AURKA (in HMC-1.2 cells). Protein expression and post-translational modifications were assessed by WB and immunoblotting. Protein interactions were tested by using co-immunoprecipitation. Apoptotic cell death was evaluated by flow cytometry after annexin V and propidium iodide staining, respectively. Drug cytotoxicity in in vitro experiments was evaluated by clonogenic assays. Results Here, we show that the proteasome inhibitors suppress cell growth and induce apoptosis in neoplastic mast cells by promoting SETD2/H3K36Me3 re-expression. Moreover, we found that Aurora kinase A and MDM2 are implicated in SETD2 loss of function in AdvSM. In line with this observation, direct or indirect targeting of Aurora kinase A with alisertib or volasertib induced reduction of clonogenic potential and apoptosis in human mast cell lines and primary neoplastic cells from patients with AdvSM. Efficacy of Aurora A or proteasome inhibitors was comparable to that of the KIT inhibitor avapritinib. Moreover, combination of alisertib (Aurora A inhibitor) or bortezomib (proteasome inhibitor) with avapritinib allowed to use lower doses of each drug to achieve comparable cytotoxic effects. Conclusions Our mechanistic insights into SETD2 non-genomic loss of function in AdvSM highlight the potential value of novel therapeutic targets and agents for the treatment of patients who fail or do not tolerate midostaurin or avapritinib.

High-grade (HG) gastroenteropancreatic (GEP) neuroendocrine neoplasms (NEN) are rare but have a very poor prognosis and represent a severely understudied class of tumours. Molecular data for HG GEP-NEN are limited, and treatment strategies for the carcinoma subgroup (HG GEP-NEC) are extrapolated from small-cell lung cancer (SCLC). After pathological re-evaluation, we analysed DNA from tumours and matched blood samples from 181 HG GEP-NEN patients; 152 neuroendocrine carcinomas (NEC) and 29 neuroendocrine tumours (NET G3). Based on the sequencing of 360 cancer-related genes, we assessed mutations and copy number alterations (CNA). For NEC, frequently mutated genes were TP53 (64%), APC (28%), KRAS (22%) and BRAF (20%). RB1 was only mutated in 14%, but CNAs affecting RB1 were seen in 34%. Other frequent copy number losses were ARID1A (35%), ESR1 (25%) and ATM (31%). Frequent amplifications/gains were found in MYC (51%) and KDM5A (45%). While these molecular features had limited similarities with SCLC, we found potentially targetable alterations in 66% of the NEC samples. Mutations and CNA varied according to primary tumour site with BRAF mutations mainly seen in colon (49%), and FBXW7 mutations mainly seen in rectal cancers (25%). Eight out of 152 (5.3%) NEC were microsatellite instable (MSI). NET G3 had frequent mutations in MEN1 (21%), ATRX (17%), DAXX, SETD2 and TP53 (each 14%). We show molecular differences in HG GEP-NEN, related to morphological differentiation and site of origin. Limited similarities to SCLC and a high fraction of targetable alterations indicate a high potential for better-personalized treatments.

Precise quantification of copy‐number alterations (CNAs) in a tumor genome is difficult. We have applied a comprehensive copy‐number analysis method, digital multiplex ligation‐dependent probe amplification (digitalMLPA), for targeted gene copy‐number analysis in clear cell renal cell carcinoma (ccRCC). Copy‐number status of all chromosomal arms and 11 genes was determined in 60 ccRCC samples. Chromosome 3p loss and 5q gain, known as early changes in ccRCC development, as well as losses at 9p and 14q were detected in 56/60 (93.3%), 31/60 (51.7%), 11/60 (18.3%), and 33/60 (55%), respectively. Through gene expression analysis, a significant positive correlation was detected in terms of 14q loss determined using digitalMLPA and downregulation of mRNA expression ratios with HIF1A and L2HGDH (P = .0253 and .0117, respectively). Patients with early metastasis (, Our digitalMLPA approach of measuring copy‐number alterations for all chromosomal arms can distinguish patients with early metastasis from metastasis‐free patients, and will facilitate the selection of patients who may develop metastasis.

Human SETD2 is the unique histone methyltransferase that generates H3K36 trimethylation (H3K36me3), an epigenetic mark that plays a key role in normal hematopoiesis. Interestingly, recurrent inactivating mutations of SETD2 and aberrant H3K36me3 are increasingly reported to be involved in hematopoietic malignancies. Benzene (BZ) is a ubiquitous environmental pollutant and carcinogen that causes leukemia. The leukemogenic properties of BZ depend on its biotransformation in the bone marrow into oxidative metabolites, in particular 1,4-benzoquinone (BQ). This hematotoxic metabolite can form DNA and protein adducts that result in the damage and the alteration of cellular processes. Recent studies suggest that BZ-dependent leukemogenesis could depend on epigenetic perturbations, notably aberrant histone methylation. We investigated whether H3K36 trimethylation by SETD2 could be impacted by BZ and its hematotoxic metabolites. Herein, we show that BQ, the major leukemogenic metabolite of BZ, inhibits irreversibly the human histone methyltransferase SETD2, resulting in decreased H3K36me3. Our mechanistic studies further indicate that the BQ-dependent inactivation of SETD2 is due to covalent binding of BQ to reactive Zn-finger cysteines within the catalytic domain of the enzyme. The formation of these quinoprotein adducts results in loss of enzyme activity and protein crosslinks/oligomers. Experiments conducted in hematopoietic cells confirm that exposure to BQ results in the formation of SETD2 crosslinks/oligomers and concomitant loss of H3K36me3 in cells. Taken together, our data indicate that BQ, a major hematotoxic metabolite of BZ, could contribute to BZ-dependent leukemogenesis by perturbing the functions of SETD2, a histone lysine methyltransferase of hematopoietic relevance. SIGNIFICANCE STATEMENT: Benzoquinone is a major leukemogenic metabolite of benzene. Dysregulation of histone methyltransferase is involved in hematopoietic malignancies. This study found that benzoquinone irreversibly impairs SET domain containing 2, a histone H3K36 methyltransferase that plays a key role in hematopoiesis. Benzoquinone forms covalent adducts on Zn-finger cysteines within the catalytic site, leading to loss of activity, protein crosslinks/oligomers, and concomitant decrease of H3K36me3 histone mark. These data provide evidence that a leukemogenic metabolite of benzene can impair a key epigenetic enzyme.

Alterations in global histone methylation regulate gene expression and participate in cancer onset and progression. The profile of histone methylation marks in pediatric astrocytomas is currently understudied with limited data on their distribution among grades. The global expression patterns of repressive histone marks H3K9me3, H3K27me3, and H4K20me3 and active H3K4me3 and H3K36me3 along with their writers SUV39H1, SETDB1, EZH2, MLL2, and SETD2 were investigated in 46 pediatric astrocytomas and normal brain tissues. Associations between histone marks and modifying enzymes with clinicopathological characteristics and disease-specific survival were studied along with their functional impact in proliferation and migration of pediatric astrocytoma cell lines using selective inhibitors in vitro. Upregulation of histone methyltransferase gene expression and deregulation of histone code were detected in astrocytomas compared to normal brain tissues, with higher levels of SUV39H1, SETDB1, and SETD2 as well as H4K20me3 and H3K4me3 histone marks. Pilocytic astrocytomas exhibited lower MLL2 levels compared to diffusely infiltrating tumors indicating a differential pattern of epigenetic regulator expression between the two types of astrocytic neoplasms. Moreover, higher H3K9me3, H3K36me3, and SETDB1 expression was detected in grade IIΙ/IV compared to grade II astrocytomas. In univariate analysis, elevated H3K9me3 and MLL2 and diminished SUV39H1 expression adversely affected survival. Upon multivariate survival analysis, only SUV39H1 expression was revealed as an independent prognostic factor of adverse significance. Treatment of pediatric astrocytoma cell lines with SUV39H1 inhibitor reduced proliferation and cell migration. Our data implicate H3K9me3 and SUV39H1 in the pathobiology of pediatric astrocytomas, with SUV39H1 yielding prognostic information independent of other clinicopathologic variables. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13311-021-01090-x.

Background Heterogeneity of leukemia-initiating cells (LICs) is a major obstacle in acute myeloid leukemia (AML) therapy. Accumulated evidence indicates that the coexistence of multiple types of LICs with different pathogenicity in the same individual is a common feature in AML. However, the functional heterogeneity including the drug response of coexistent LICs remains unclear. Therefore, this study aimed to clarify the intra-heterogeneity in LICs that can help predict leukemia behavior and develop more effective treatments. Methods Spleen cells from the primary Setd2-/- -AML mouse were transplanted into C57BL/6 recipient mice to generate a transplantable model. Flow cytometry was used to analyze the immunophenotype of the leukemic mice. Whole-genome sequencing was conducted to detect secondary hits responsible for leukemia transformation. A serial transplantation assay was used to determine the self-renewal potential of Setd2-/- -AML cells. A limiting-dilution assay was performed to identify the LIC frequency in different subsets of leukemia cells. Bulk and single-cell RNA sequencing were performed to analyze the transcriptional heterogeneity of LICs. Small molecular inhibitor screening and in vivo drug treatment were employed to clarify the difference in drug response between the different subsets of LICs. Results In this study, we observed an aged Setd2-/- mouse developing AML with co-mutation of NrasG12S and BrafK520E . Further investigation identified two types of LICs residing in the c-Kit+ B220+ Mac-1- and c-Kit+ B220+ Mac-1+ subsets, respectively. In vivo transplantation assay disclosed the heterogeneity in differentiation between the coexistent LICs. Besides, an intrinsic doxorubicin-resistant transcriptional signature was uncovered in c-Kit+ B220+ Mac-1+ cells. Indeed, doxorubicin plus cytarabine (DA), the standard chemotherapeutic regimen used in AML treatment, could specifically kill c-Kit+ B220+ Mac-1- cells, but it hardly affected c-Kit+ B220+ Mac-1+ cells. Transcriptome analysis unveiled a higher activation of RAS downstream signaling pathways in c-Kit+ B220+ Mac-1+ cells than in c-Kit+ B220+ Mac-1- cells. Combined treatment with DA and RAS pathway inhibitors killed both c-Kit+ B220+ Mac-1- and c-Kit+ B220+ Mac-1+ cells and attenuated disease progression. Conclusions This study identified two cell subsets enriched for LICs in murine Setd2-/- -AML and disclosed the transcriptional and functional heterogeneity of LICs, revealing that the coexistence of different types of LICs in this model brings about diverse drug response.

Gene discovery efforts in autism spectrum disorder have identified heterozygous defects in chromatin remodeller genes, the ‘readers, writers and erasers’ of methyl marks on chromatin, as major contributors to this disease. Despite this advance, a convergent aetiology between these defects and aberrant chromatin architecture or gene expression has remained elusive. Recently, data have begun to emerge that chromatin remodellers also function directly on the cytoskeleton. Strongly associated with autism spectrum disorder, the SETD2 histone methyltransferase for example, has now been shown to directly methylate microtubules of the mitotic spindle. However, whether microtubule methylation occurs in post-mitotic cells, for example on the neuronal cytoskeleton, is not known. We found the SETD2 α-tubulin lysine 40 trimethyl mark occurs on microtubules in the brain and in primary neurons in culture, and that the SETD2 C-terminal SRI domain is required for binding and methylation of α-tubulin. A CRISPR knock-in of a pathogenic SRI domain mutation (Setd2SRI) that disables microtubule methylation revealed at least one wild-type allele was required in mice for survival, and while viable, heterozygous Setd2SRI/wtmice exhibited an anxiety-like phenotype. Finally, whereas RNA-sequencing (RNA-seq) and chromatin immunoprecipitation-sequencing (ChIP-seq) showed no concomitant changes in chromatin methylation or gene expression in Setd2SRI/wtmice, primary neurons exhibited structural deficits in axon length and dendritic arborization. These data provide the first demonstration that microtubules of neurons are methylated, and reveals a heterozygous chromatin remodeller defect that specifically disables microtubule methylation is sufficient to drive an autism-associated phenotype.

Patients with polycystic kidney disease (PKD) are at a high risk of developing renal cell carcinoma (RCC). However, little is known about genetic alterations or changes in signaling pathways during the transition from PKD to RCC. SET domain–containing 2 (SETD2) is a histone methyltransferase, which catalyzes tri-methylation of H3K36 (H3K36me3) and has been identified as a tumor suppressor in clear cell renal cell carcinoma (ccRCC), but the underlying mechanism remains largely unexplored. Here we report that knockout of SETD2 in a c-MYC–driven PKD mouse model drove the transition to ccRCC. SETD2 inhibited β-catenin activity at transcriptional and posttranscriptional levels by competing with β-catenin for binding promoters of target genes and maintaining transcript levels of members of the β-catenin destruction complex. Thus, SETD2 deficiency enhanced the epithelial-to-mesenchymal transition and tumorigenesis through the hyperactivation of Wnt/β-catenin signaling. Our findings reveal previously unrecognized roles of SETD2-mediated competitive DNA binding and H3K36me3 modification in regulating Wnt/β-catenin signaling during the transition from PKD to ccRCC. The novel autochthonous mouse models of PKD and ccRCC will be useful for preclinical research into disease progression. Significance: These findings characterize multiple mechanisms by which SETD2 inhibits β-catenin activity during the transition of polycystic kidney disease to renal cell carcinoma, providing a potential therapeutic strategy for high-risk patients.

Purpose SETD2 is one of the key epigenetic regulatory genes involved in histone modifications. Its alterations were potentially oncogenic and commonly found in cancers. Interestingly, SETD2 is one of the most frequent mutated genes found exclusively in phyllodes tumor of the breast (PT). However, little has been done to further characterize SETD2 alterations in PT. Methods In this study, we examined the alterations of SETD2 gene and protein expression in a large cohort of PTs. Their correlations with SETD2 downstream target, H3K36me3 expression, and clinicopathologic features in PT were also assessed. Results SETD2 mutation was found in 15.9% of our cases and was mostly predicted to be damaging mutations. Interestingly, SETD2 mutations were associated with lower H3K36me3 expression, particularly those with damaging mutations (p = .041). Neither SETD2 mutations nor H3K36me3 expression was associated with PT grading and other clinicopathological features. By contrast, the SETD2 protein expression cannot reflect its mutation status and showed a different trend of clinicopathological correlations from H3K36me3. Conclusions Our findings may suggest a potential involvement of epigenetic regulation via SETD2 alterations and downstream H3K36me3 on PT development. SETD2 mutations may occur early in the pathogenic process of PTs and its loss per se may not be sufficient for progression to malignancy. Exclusive alterations of SETD2 in PT can be used as markers for the diagnosis of fibroepithelial lesions. The association of H3K36me3 with SETD2 mutations may also indicate the value of evaluation of H3K36me3 expression in the diagnosis of fibroepithelial lesions.

Pulmonary arterial hypertension (PAH) is a fatal disease whose molecular mechanism is unknown. The trimethylation of lysine 36 on histone 3 (H3K36me3) catalyzed by SETD2 and the modification of N6-methyladenine (m6A) mRNA mediated by METTL14 play important roles in a variety of normal and pathological biological processes. However, the role of these epigenetic controls in the pathogenesis of PAH remains unclear. In this study, the expression of SETD2 and METTL14 was elevated in pulmonary artery smooth muscle cells (PASMCs) of hypoxia-induced PAH mice. We further constructed a mouse model with SETD2 specific knockout in smooth muscle cells (SETD2SM22α Cre). Our results suggest that the lack of SETD2 in SMCs protected mice from hypoxia-induced PAH and significantly reduced right ventricular systolic pressure (RVSP), right ventricular/left ventricular plus septum [RV/(LV+S)] weight ratio, and pulmonary median width. In addition, the absence of SETD2 in SMCs alleviates the level of METTL14 expression and the m6A RNA methylation level in PAH SMCs. These results obtained from mice suggest that strategies that target the inhibition of SETD2/METTL14 activity may be a viable treatment for PAH in a clinical setting.

Purpose: In contrast to recurrence after initial diagnosis of stage I–III breast cancer [recurrent metastatic breast cancer (rMBC)], de novo metastatic breast cancer (dnMBC) represents a unique setting to elucidate metastatic drivers in the absence of treatment selection. We present the genomic landscape of dnMBC and association with overall survival (OS). Experimental Design: Targeted DNA sequencing (OncoPanel) was prospectively performed on either primary or metastatic tumors from 926 patients (212 dnMBC and 714 rMBC). Single-nucleotide variants, copy-number variations, and tumor mutational burden (TMB) in treatment-naïve dnMBC primary tumors were compared with primary tumors in patients who ultimately developed rMBC, and correlated with OS across all dnMBC. Results: When comparing primary tumors by subtype, MYB amplification was enriched in triple-negative dnMBC versus rMBC (21.1% vs. 0%, P = 0.0005, q = 0.111). Mutations in KMTD2, SETD2, and PIK3CA were more prevalent, and TP53 and BRCA1 less prevalent, in primary HR+/HER2− tumors of dnMBC versus rMBC, though not significant after multiple comparison adjustment. Alterations associated with shorter OS in dnMBC included TP53 (wild-type: 79.7 months; altered: 44.2 months; P = 0.008, q = 0.107), MYC (79.7 vs. 23.3 months; P = 0.0003, q = 0.011), and cell-cycle (122.7 vs. 54.9 months; P = 0.034, q = 0.245) pathway genes. High TMB correlated with better OS in triple-negative dnMBC (P = 0.041). Conclusions: Genomic differences between treatment-naïve dnMBC and primary tumors of patients who developed rMBC may provide insight into mechanisms underlying metastatic potential and differential therapeutic sensitivity in dnMBC. Alterations associated with poor OS in dnMBC highlight the need for novel approaches to overcome potential intrinsic resistance to current treatments.

This scientific commentary refers to ‘Neuronal SETD2 activity links microtubule methylation to an anxiety-like phenotype in mice’, by Koenning et al. (doi:10.1093/brain/awab200).

The histone H3 lysine 36 methyltransferase SET-domain-containing 2 (SETD2) has been reported to be frequently mutated or deleted in many types of human cancer. However, the role of SETD2 in lung adenocarcinoma (LUAD) has not been well documented. In the present study, we found that SETD2 was significantly down-regulated both in LUAD tissues and cell lines. Functionally, the increased expression of SETD2 significantly attenuated the proliferation of cancer cells by affecting the cell cycle, whereas SETD2 deficiency dramatically improved these proliferative abilities of cancer cells. Through conjoint analysis of RNA-seq and ChIP data, we identified a functional target gene of SETD2, CXCL1, and its expression was negatively correlated with that of SETD2. Moreover, SETD2 deletion stimulated cell cycle-related proteins to promote LUAD. Further mechanistic studies demonstrated that histone H3 lysine 36 trimethylation (H3K36me3) catalyzed by SETD2 interacted with the promoter of CXCL1 to regulate its transcription and downstream signaling pathways, contributing to tumorigenesis in vitro and in vivo. Our findings suggested that SETD2 inhibited tumor growth via suppressing CXCL1-mediated activation of cell cycle, indicating that the regulation of H3K36me3 level by targeting SETD2 and/or the administration of downstream CXCL1 might represent a potential therapeutic way for new treatment in LUAD.

Objectives While aberrations in the VHL gene and chromosome 3p resulting in clear cell renal cell carcinoma (CCRCC) are well established, we know that additional mutations in chromatin remodeling genes PBRM1, SETD2, and BRCA1-associated protein 1 (BAP1) contribute to pathogenesis in some cases. Given the known aggressive clinical behavior of BAP1-mutated CCRCC, we sought to define the pathologic phenotype of BAP1-mutated CCRCC. Methods We identified 14 cases of molecularly proven BAP1-mutated CCRCC and investigated their clinicopathologic features. Results BAP1-mutated CCRCC frequently showed papillary, tubulopapillary, or expanded nested architecture; demonstrated granular to diffusely eosinophilic cytoplasm with prominent eosinophilic globules; and contained high-grade nuclei. This morphology demonstrates significant overlap with Xp11 translocation renal cell carcinoma (RCC). Immunohistochemistry notably demonstrates loss of BAP1 expression in almost all tumors, in addition to strong p504S expression. A conventional CCRCC component was frequently present adjacent to the characteristic BAP1 areas and showed retained BAP1 expression and only patchy p504S. Approximately two-thirds of BAP1-mutated CCRCCs were stage pT3, renal vein invasion was common, and 50% developed metastases. Conclusions Herein, we describe the histologic and immunohistochemical findings in BAP1-mutated CCRCC, which has important implications for utilization of molecular testing, prognosis, future therapeutics, and distinction from other RCC subtypes such as Xp11 translocation RCC.

De novo DNA methylation (DNAme) in mammalian germ cells is dependent on DNMT3A and DNMT3L. However, oocytes and spermatozoa show distinct patterns of DNAme. In mouse oocytes, de novo DNAme requires the lysine methyltransferase (KMTase) SETD2, which deposits H3K36me3. We show here that SETD2 is dispensable for de novo DNAme in the male germline. Instead, the lysine methyltransferase NSD1, which broadly deposits H3K36me2 in euchromatic regions, plays a critical role in de novo DNAme in prospermatogonia, including at imprinted genes. However, males deficient in germline NSD1 show a more severe defect in spermatogenesis than Dnmt3l-/- males. Notably, unlike DNMT3L, NSD1 safeguards a subset of genes against H3K27me3-associated transcriptional silencing. In contrast, H3K36me2 in oocytes is predominantly dependent on SETD2 and coincides with H3K36me3. Furthermore, females with NSD1-deficient oocytes are fertile. Thus, the sexually dimorphic pattern of DNAme in mature mouse gametes is orchestrated by distinct profiles of H3K36 methylation.

Background Brain metastases are a significant cause of mortality and morbidity for patients with melanoma. We hypothesize that the development of brain metastases may be explained by molecular heterogeneity between primary cutaneous melanoma (PCM) or extracranial (ECM) and brain (MBM) melanoma metastases. Materials and methods We compared next-generation sequencing, tumor mutational burden (TMB), and immunohistochemical staining for PD-L1 expression, among 132 MBM, 745 PCM, and 1190 ECM. Results The most common genetic alterations among MBM included: BRAF (52.4%), NRAS (26.6%), CDKN2A (23.3%), NF1 (18.9%), TP53 (18%), ARID2 (13.8%), SETD2 (11.9%), and PBRM1 (7.5%). Four genes were found with higher frequency among MBM compared to PCM or ECM: BRAF (52.4% v 40.4% v 40.9%), SETD2 (11.9% v 1.9% v 3.9%), PBRM1 (7.5% v 1.6% v 2.6%), and DICER1 (4.4% v 0.6% v 0.4%). MBM showed higher TMB (p = .04) and higher PD-L1 expression (p = .002), compared to PCM. PD-L1 expression was slightly higher among MBM compared to ECM (p = .042), but there was no difference between TMB (p = .21). Conclusions Our findings suggest a unique molecular profile for MBM, including higher rates of BRAF mutations, higher TMB and higher PD-L1 expression, and also implicate chromatin remodeling in the pathogenesis of MBM.

Cell size varies between cell types but is tightly regulated by cell intrinsic and extrinsic mechanisms. Cell size control is important for cell function, and changes in cell size are frequently observed in cancer. Here, we uncover a role for SETD2 in regulating cell size. SETD2 is a lysine methyltransferase and a tumor suppressor protein involved in transcription, RNA processing and DNA repair. At the molecular level, SETD2 is best known for associating with RNA polymerase II through its Set2-Rbp1 interacting (SRI) domain and methylating histone H3 on lysine 36 (H3K36) during transcription. Using multiple independent perturbation strategies, we identify SETD2 as a negative regulator of global protein synthesis rates and cell size. We provide evidence that overexpression of the H3K36 demethylase KDM4A or the oncohistone H3.3K36M also increase cell size. In addition, ectopic overexpression of a decoy SRI domain increased cell size, suggesting that the relevant substrate is engaged by SETD2 via its SRI domain. These data add a central role of SETD2 in regulating cellular physiology and warrant further studies on separating the different functions of SETD2 in cancer development., Journal of Cell Science, 135 (19), ISSN:1477-9137, ISSN:0021-9533

Histone modification is an important form of epigenetic regulation. Thereinto, histone methylation is a critical determination of chromatin states, participating in multiple cellular processes. As a conserved histone methylation mark, histone 3 lysine 36 trimethylation (H3K36me3) can mediate multiple transcriptional-related events, such as the regulation of transcriptional activity, transcription elongation, pre-mRNA alternative splicing, and RNA m6A methylation. Additionally, H3K36me3 also contributes to DNA damage repair. Given the crucial function of H3K36me3 in genome regulation, the roles of H3K36me3 and its sole methyltransferase SETD2 in pathogenesis, especially malignancies, have been emphasized in many studies, and it is conceivable that disruption of histone methylation regulatory network composed of “writer”, “eraser”, “reader”, and the mutation of H3K36me3 codes have the capacity of powerfully modulating cancer initiation and development. Here we review H3K36me3-mediated biological processes and summarize the latest findings regarding its role in cancers. We highlight the significance of epigenetic combination therapies in cancers.

Histone methyltransferase SETD2 plays a critical role in maintaining genomic integrity and stability. Here, we investigated the characteristics of SETD2 somatic mutation in the cancer genome atlas pan-cancer cohort. Our data revealed that, compared with SETD2 nonmutant patients, SETD2 mutant patients had higher tumor mutation burden and microsatellite instability. In addition, the transcriptions of most genes related to immune activities were upregulated in patients with SETD2 mutant tumors. Further examination of cancer patients treated with immune checkpoint inhibitors suggested SETD2 mutation was associated with favorable clinical outcomes. These results have implication for the personalization of cancer immunotherapy.

Aim: Steroid sulfotransferase (SULT) plays physiological roles but its role in clear cell-renal cell carcinoma (ccRCC) remains unclear. We therefore investigated genetic alteration of steroid SULT genes in ccRCC. Results: Overexpression of any of SULT genes occurred in ~8% of ccRCC patients. Overexpression of steroid SULT genes was associated with worsened prognosis. Steroid SULT gene-upregulated ccRCC cases showed mutual exclusivity with mutations of VHL, SETD2 and PBRM1, and with focal deletions of 3p and 9p, respectively. Expressions of SULT genes were negatively correlated with that of VHL, SETD2 and PBRM1, respectively. While no cancer-intrinsic pathway was enriched, immune signatures were significantly enriched in SULT gene-overexpressed cases, resulting in significantly fewer infiltration of lymphocytes. Targeting SULT1B1 significantly inhibited growth of ccRCC cells. Conclusion: Steroid SULT genes were associated with worsened prognosis and with immune exclusion in ccRCC. Methods: In silico reproduction of TGGA and GTEx datasets was performed. Data were processed comprehensively using the platforms of cBioPotal, GEPIA, Human Protein Atlas, TIMER, respectively. Functional annotation was analyzed using platforms of NET-GE and GSEA, respectively. In vitro assays were performed for validation.

Background Over the past two decades, the importance of genetic factors in the development of FSGS has become increasingly clear. However, despite many known monogenic causes of FSGS, single gene defects explain only 30% of cases. Methods To investigate mutations underlying FSGS, we sequenced 662 whole exomes from individuals with sporadic or familial FSGS. After quality control, we analyzed the exome data from 363 unrelated family units with sporadic or familial FSGS and compared this to data from 363 ancestry-matched controls. We used rare variant burden tests to evaluate known disease-associated genes and potential new genes. Results We validated several FSGS-associated genes that show a marked enrichment of deleterious rare variants among the cases. However, for some genes previously reported as FSGS related, we identified rare variants at similar or higher frequencies in controls. After excluding such genes, 122 of 363 cases (33.6%) had rare variants in known disease-associated genes, but 30 of 363 controls (8.3%) also harbored rare variants that would be classified as "causal" if detected in cases; applying American College of Medical Genetics filtering guidelines (to reduce the rate of false-positive claims that a variant is disease related) yielded rates of 24.2% in cases and 5.5% in controls. Highly ranked new genes include SCAF1, SETD2, and LY9. Network analysis showed that top-ranked new genes were located closer than a random set of genes to known FSGS genes. Conclusions Although our analysis validated many known FSGS-causing genes, we detected a nontrivial number of purported "disease-causing" variants in controls, implying that filtering is inadequate to allow clinical diagnosis and decision making. Genetic diagnosis in patients with FSGS is complicated by the nontrivial rate of variants in known FSGS genes among people without kidney disease.

Background Renal papillary cell carcinoma (KIRP) is a relatively rare renal malignancy. Although KIRP subtyping about clinical relevance has been defined, there have been scarce number of studies on the molecular characteristics of KIRP subtypes. Method In this study, a independent samples t-test was used to identify differentially expressed (DE) miRNAs between tumor and normal samples of KIRP. Meanwhile, we performed unsupervised clustering using DE miRNA expression data to analyze molecular characteristics of KIRP. The Partitioning Around Medoids clustering approach was used to identify molecular subtypes. The cumulative distribution function (CDF), proportion of ambiguously clustered pairs (PAC), principal component analysis (PCA) and consensus heatmaps were used to assess the optimal subtypes. In the differential molecular subtypes, we performed an integrated analysis of survival, DE genes, biological function and somatic mutations on the cohort of KIRP patients from The Cancer Genome Atlas. Results From solutions with 2, 3, 4, 5, 6 and 7 clusters we selected three KIRP molecular subtypes after assessing PCA, PAC, CDF and consensus heatmaps. We found that the three subtypes are associated with different overall survival and molecular characteristics. Compared with subtype1 and subtype3, subtype2 had a better prognosis in KIRP patients. After exploring their signaling pathways and biological characteristics, we identified the significantly enriched KEGG pathways and Gene Ontology terms for the three subtypes. The distribution of PARD6B, SETD2, STAG2, CUL3, TNRC18, LRBA, IGSF9B and DUNC1H1 mutations differed between the subtypes. Conclusion We performed unsupervised clustering using differentially expressed miRNA expression data and described the three KIRP molecular subtypes. The three subtypes differed in overall survival, molecular characteristics and gene mutation frequency.

Well-differentiated papillary mesothelioma is an uncommon mesothelial neoplasm that most frequently arises in the peritoneal cavity of women of reproductive age. Whereas malignant mesothelioma is an aggressive tumor associated with poor outcome, well-differentiated papillary mesothelioma typically exhibits indolent behavior. However, histologically differentiating between these two entities can be challenging, necessitating the development of distinguishing biomarkers. While the genetic alterations that drive malignant mesothelioma have recently been determined, the molecular pathogenesis of well-differentiated papillary mesothelioma is unknown. Here we performed genomic profiling on a cohort of ten well-differentiated papillary mesothelioma of the peritoneum. We identified that all tumors harbored somatic missense mutations in either the TRAF7 or CDC42 genes, and lacked alterations involving BAP1, NF2, CDKN2A, DDX3X, SETD2, and ALK that are frequent in malignant mesothelioma. We recently identified that another mesothelial neoplasm, adenomatoid tumor of the genital tract, is genetically defined by somatic missense mutations in the TRAF7 gene, indicating a shared molecular pathogenesis between well-differentiated papillary mesothelioma and adenomatoid tumors. To the best of our knowledge, well-differentiated papillary mesothelioma is the first human tumor type found to harbor recurrent mutations in the CDC42 gene, which encodes a Rho family GTPase. Immunohistochemistry demonstrated intact BAP1 expression in all cases of well-differentiated papillary mesothelioma, indicating that this is a reliable marker for distinguishing well-differentiated papillary mesothelioma from malignant mesotheliomas that frequently display loss of expression. Additionally, all well-differentiated papillary mesothelioma demonstrated robust expression of L1 cell adhesion molecule (L1CAM), a marker of NF-kB pathway activation, similar to that observed in adenomatoid tumors. In contrast, we have previously shown that L1CAM staining is not observed in normal mesothelial cells and malignant mesotheliomas of the peritoneum. Together, these studies demonstrate that well-differentiated papillary mesothelioma is genetically defined by mutually exclusive mutations in TRAF7 and CDC42 that molecularly distinguish this entity from malignant mesothelioma.

Introduction Small renal masses (SRMs) with evidence of clear cell renal cell carcinoma (ccRCC) are understudied. Current algorithms for the management of SRMs include surgical resection, ablation, and active surveillance. We sought to identify genomic biomarkers that could potentially refine the management of ccRCC in SRMs, especially in patients being evaluated for active surveillance. Methods We identified patients who had SRMs (4 cm or less) at time of surgery, had sequencing performed on their primary tumor and had a diagnosis of ccRCC. Patients were selected from 3 publicly available cohorts, The Cancer Genome Atlas ( n = 110), University of Tokyo ( n = 37), The International Cancer Genome Consortium ( n = 31), and from our own institutional prospective database ( n = 25). Among this cohort we analyzed mutations present in at least 5% of tumors, assessing for the enrichment of mutations and progression-free survival using the composite endpoint of recurrence or death of disease. Analysis was adjusted for multiple testing. A Cox regression model was used to assess clinical variables with significant mutations. Results In total, 203 patients were available for analysis. Median follow-up was 43.1 months among survivors. Mutations in VHL, PBRM1, SETD2, BAP1, KDM5C , and MTOR were present in more than 5% of tumors. Twenty-three patients (11.3%) had recurrence or died of their disease. Mutations in KDM5C were associated with inferior survival from either recurrence or death from disease, adjusted P 0.033. Conclusions We identified mutations in SRMs in ccRCC that are associated with recurrence and lethality. The strongest association was seen in those with KDM5C mutations. Use of these genomic biomarkers may improve stratification of patients with SRMs and for those who may be appropriate for active surveillance. Prospective evaluation of these markers is needed.

Aims Mucoepidermoid carcinomas (MEC) are the most common malignant neoplasms of salivary glands, but are uncommon in other sites. Salivary gland MEC are most frequently associated with CRTC1-MAML2 translocations. Exceedingly rare MEC of the breast demonstrate a basal-like and often triple (oestrogen and progesterone receptor, HER2)-negative immunophenotype, with a single case previously reported to show MAML2 rearrangement, although the fusion partner was not known. Comprehensive genomic studies of breast MEC are lacking. In this study, we analysed the immunophenotype and molecular landscape of two breast MEC to elucidate the pathogenesis of these rare tumours. Methods and results Two breast MEC were subjected to capture-based next-generation DNA sequencing of 479 cancer-related genes. The presence of the CRTC1-MAML2 fusion transcript was interrogated by reverse transcriptase-polymerase chain reaction. In addition, the immunoprofiles of breast MEC were compared to salivary gland MEC. Both breast MEC harboured CRTC1-MAML2 fusions. In contrast to most triple-negative breast carcinomas of no special type, the mutational burden of MEC was very low, with one case demonstrating only an inactivating SETD2 mutation, and the other harbouring no somatic variants in genes on the panel. No copy number alterations were identified. The immunoprofiles of breast and salivary gland MEC were overlapping, but not identical. Conclusions The findings highlight MEC as a breast cancer subtype more closely related to its salivary gland counterpart than to basal-like/triple-negative breast cancers of no special type.

SET domain-containing protein 2 (SETD2), a histone methyltransferase, has been identified as a target of interest in certain hematological malignancies, including multiple myeloma. This account details the discovery of EPZ-719, a novel and potent SETD2 inhibitor with a high selectivity over other histone methyltransferases. A screening campaign of the Epizyme proprietary histone methyltransferase-biased library identified potential leads based on a 2-amidoindole core. Structure-based drug design (SBDD) and drug metabolism/pharmacokinetics (DMPK) optimization resulted in EPZ-719, an attractive tool compound for the interrogation of SETD2 biology that enables in vivo target validation studies.

Objectives Cutaneous wound healing is one of the major medical problems worldwide. Epigenetic modifiers have been identified as important players in skin development, homeostasis and wound repair. SET domain–containing 2 (SETD2) is the only known histone H3K36 tri‐methylase; however, its role in skin wound healing remains unclear. Materials and Methods To elucidate the biological role of SETD2 in wound healing, conditional gene targeting was used to generate epidermis‐specific Setd2‐deficient mice. Wound‐healing experiments were performed on the backs of mice, and injured skin tissues were collected and analysed by haematoxylin and eosin (H&E) and immunohistochemical staining. In vitro, CCK8 and scratch wound‐healing assays were performed on Setd2‐knockdown and Setd2‐overexpression human immortalized keratinocyte cell line (HaCaT). In addition, RNA‐seq and H3K36me3 ChIP‐seq analyses were performed to identify the dysregulated genes modulated by SETD2. Finally, the results were validated in functional rescue experiments using AKT and mTOR inhibitors (MK2206 and rapamycin). Results Epidermis‐specific Setd2‐deficient mice were successfully established, and SETD2 deficiency resulted in accelerated re‐epithelialization during cutaneous wound healing by promoting keratinocyte proliferation and migration. Furthermore, the loss of SETD2 enhanced the scratch closure and proliferation of keratinocytes in vitro. Mechanistically, the deletion of Setd2 resulted in the activation of AKT/mTOR signalling pathway, while the pharmacological inhibition of AKT and mTOR with MK2206 and rapamycin, respectively, delayed wound closure. Conclusions Our results showed that SETD2 loss promoted cutaneous wound healing via the activation of AKT/mTOR signalling., The epidermis‐specific Setd2‐deficient mice showed accelerated re‐epithelialization during cutaneous wound healing by promoting keratinocytes proliferation and migration. Mechanistically, deletion of Setd2 resulted in the activation the AKT/mTOR signalling pathway and pharmacological inhibitions of AKT and mTOR with MK2206 and rapamycin delayed wound closure, respectively.

Background:Nuclear protein in testis (NUT) midline carcinoma (NMC) is a rare and highly aggressive tumor with the bromodomain containing 4 (BRD4)-NUT (NUTM1) gene fusion. BRD4 is a member of the bromodomain and extra-terminal domain (BET) family of proteins, and BET inhibitors have been investigated in NMC clinical trials. However, few targeted therapies are available for NMC, and novel therapeutic targets remain to be determined. We determined the role of two epigenetic regulators as possible therapeutic targets for NMC. Methods:We performed next-generation sequencing (NGS) in NMC cell lines (HCC2429 and Ty82). H3K36me3 expression was studied using western blotting. The efficacy of AZD1775, a WEE1 inhibitor, was evaluated using the MTS and γH2AX assays. We established an NMC cell line that was resistant to BET inhibitors. The sensitivity of the cells resistant to AZD1775 was analyzed using the MTS assay. RNA sequencing was performed to determine miRNA expression levels. TaqMan miRNA assays were used to analyze miR-21 expression. The efficacy of the miR-21 inhibitor was evaluated using the MTS assay. We established a digital PCR (dPCR) assay to detect NUT gene rearrangements to identify patients with NMC. Using NGS, a patient with NMC was identified with the SETD2 mutation.Results:SETD2 mutation (p.Ser2382fs) was determined in NMC cells, in which H3K36me3 expression was depleted, indicating SETD2 loss. NMC cells were sensitive to the WEE1 inhibitor, AZD1775 in cancer cells with SETD2 deficiency. γH2AX expression was increased in NMC cells treated with AZD1775. The efficacy of the combination of AZD1775 and JQ-1 was additive. We established NMC cells that were resistant to BET inhibitors. The resistant cells were also sensitive to AZD1775. miRNA analysis revealed increased miR-21 expression in BET-inhibitor-resistant NMC cells. MiR-21 regulated the growth of NMCs. The miR-21 inhibitor suppressed the growth of BET-inhibitor-resistant cells. Thirty-two clinical samples were analyzed and NMC was identified using digital PCR assays. Tumors with the SETD2 mutation were analyzed using NGS.Conclusions:We report for the first time SET domain-containing protein 2 (SETD2) deficiency and miR-21 as novel therapeutic targets for NMC. SETD2 loss and miR-21 may be therapeutic targets for NMC.Trial registrationIn this study, we analyzed the gene alterations in human tumor samples. This study was registered in the UMIN clinical trial registered system (UMIN000043147, January 27, 2021).

Context: Genetic/genomic instability is a hallmark of CML. SETD2, a histone methyltransferase that trimethylates histone H3 on K36 (H3K36me3), has recently demonstrated a crucial role in preserving genomic integrity by modulating DNA Mismatch Repair (MMR) and Homologous Recombination (HR) repair. By Western blotting (WB), we previously observed SETD2 and H3K36me3 loss (resulting from aberrant SETD2 turnover) in 85% of blast crisis (BC) CML patients but not in newly diagnosed chronic phase (CP) patients who will achieve optimal responses. Objectives: 1. To investigate whether SETD2 is involved in the maintenance of genetic/genomic stability in CML. 2. To assess whether SETD2 loss precedes or follows progression from CP to blast crisis BC. Materials: SETD2-proficient (LAMA84) and -deficient (KCL22) CML cell lines and primary patient samples (n=86) were studied. Results: To investigate whether SETD2/H3K36me3 loss impinges on the activation and proficiency of HR, we used UV rays to induce DNA damage in SETD2 siRNA-depleted LAMA 84 (SETD2-proficient) cells. Compared to control cells, cells silenced for SETD2 displayed a marked increase in γH2AX (a marker of DNA damage) and fewer RAD51 foci (markers of ongoing HR). Assessment of MMR proficiency is ongoing. To further confirm the role of SETD2 as a tumor suppressor implicated in maintaining genomic stability in CML, we transfected KCL22 (SETD2-deficient) cells with an ectopic SETD2 plasmid. Preliminary results showed that SETD2 re-expression induced a reduction in cell doubling time, an accumulation of cells at G1/S checkpoint and a significant reduction in clonogenic potential. Studies are ongoing to assess the effects on DNA damage repair pathways. We next wondered when during disease history SETD2/H3K36me3 loss occurs. WB analysis ofpaired (diagnosis/progression) samples from four CML patients suggested that patients who will progress still have intact and functional SETD2 at diagnosis. Additional analyses are ongoing to assess whether SETD2/H3K36me3 loss precedes, hence allows to predict, progression to BC. Conclusion: Loss of SETD2/H3K36me3 is a novel, BCR-ABL1-independent mechanism of genetic instability in CML. Further investigations are needed to establish to what extent SETD2/H3K36me3 loss contributes to (and may be predictive of) disease progression. Supported by AIRC project 23001.

Context: Constitutively active KIT tyrosine kinase harboring the D816V mutation is the major driver of systemic mastocytosis (SM) pathogenesis. We have previously reported that the loss of function of SETD2 histone methyltransferase due to reduced protein stability is a common cooperating event in advanced SM (advSM). Objective: To dissect the mechanisms of action of midostaurin in advSM and to explore the potential of SETD2 as a marker of response to therapy. Materials: The mast cell (MC) leukemia cell line HMC-1 (negative for SETD2) and primary neoplastic MCs from 10 advSM patients, collected at regular time points during midostaurin treatment. Results: This study started from our preliminary observations indicating that aurora kinase A (AKA) is overexpressed and hyperactivated in advSM and is implicated in SETD2 proteasomal degradation. The new gold standard of therapy in advSM is midostaurin, which targets KIT andseveral other kinases, including AKA. We, thus, investigated whether midostaurin treatment may result in efficient AKA inhibition and subsequent SETD2 rescue. To this purpose, the HMC-1 cell line was treated with 5 µM midostaurin for 24 h, and phospho-AKA (T288), SETD2, and H3K36me3 (surrogate marker of SETD2 activity) were evaluated by WB. Midostaurin reduced AKA phosphorylation by 60%, partially restoring SETD2 expression and activity. We next wondered whether the same happens in patients treated with midostaurin. We, thus, collected and performed WB analysis on neoplastic mast cells from advSM patients before and during midostaurin treatment. We found that midostaurin may target AKA and rescue SETD2 expression and function in vivo and that SETD2/H3K36me3 rescue correlates with the clinical response to midostaurin and the reduction of KIT D816V allele burden, as assessed by digital PCR at 3, 6, and 12 months. In 8 patients who responded to midostaurin, SETD2/H3K36me3 rescue was detected by WB as early as 3 months after treatment onset, whereas 2 refractory patients did not show any increase in SETD2/H3K36me3 and maintained an unaltered KIT allele burden. Conclusions: Midostaurin treatment induces AKA partial dephosphorylation and consequent rescue of SETD2 expression and function in vitro and in vivo SETD2/H3K36me3 may serve as a biomarker of response to midostaurin. Supported by AIRC project 23001

Background The study of the genomic landscape of Chinese clear cell renal cell carcinoma (ccRCC) entered its nascence in recent years, and the clinical relevance of individual genes in Chinese ccRCC has not yet been researched. The study aimed to explore the relationships between somatic mutations and clinical behaviors in Chinese ccRCC. Methods Tumor tissue samples were obtained from 105 Chinese patients with ccRCC and deep sequencing targeting 556 cancer genes was performed. Correlation analysis, receiver operator characteristic (ROC) analysis and survival analysis were carried out using SPSS software. Results A total of 41 genes were used to investigate the relationship between genes and clinical behaviors. We found that different clinical indices were mutually correlated, and there were 12 genes associated with clinical indices. The Kaplan-Meier curves showed that high Fuhrman grade and metastatic disease at diagnosis were significantly associated with poor prognosis. Mutations in BAP1, PTEN, ERBB2, TP53, CDK8, TSC1, SETD2, or SPEN were significantly associated with poor prognosis, consistent with the results of The Cancer Genome Atlas (TCGA) cohort. Mutation of BTG1 occurred much more frequently in Chinese ccRCC (10.5%) than in the TCGA cohort (0.60%), and it was associated with a better prognosis. Conclusions A total of 8 genes (BAP1, PTEN, ERBB2, TP53, CDK8, TSC1, SETD2, and SPEN) were found to be associated with poor prognosis of ccRCC, and a new gene (BTG1) was possibly associated with the good prognosis of Chinese ccRCC.

Patients with idiopathic pulmonary fibrosis (IPF) are at higher risk of developing lung cancers including squamous cell lung carcinoma (SCC), which typically carries a poor prognosis. Although the molecular basis of cancer development subsequent to IPF has not been fully investigated, we recently reported two epigenetic phenotypes characterized by frequent and infrequent DNA hypermethylation in SCC, and an association of the infrequent hypermethylation phenotype with IPF-associated SCCs. Here, we conducted targeted exon sequencing in SCCs with and without IPF using the Human Lung Cancer Panel to investigate the genetic basis of IPF-associated SCC. SCCs with and without IPF displayed comparable numbers of total mutations (137 ± 22 vs 131 ± 27, P = .5), nonsynonymous mutations (72 ± 14 vs 69 ± 16, P = .5), indels (3.0 ± 3.5 vs 3.0 ± 3.9, P = 1) and synonymous mutations (62 ± 9.1 vs 60 ± 12, P = .5). Signature 1 was the predominant signature in SCCs with and without IPF. SETD2 and NFE2L2 mutations were significantly associated with IPF (44% vs 13%, P = .03 for SETD2; 38% vs 10%, P = .04 for NFE2L2). MYC amplification, assessed by copy number variant analysis, was also significantly associated with IPF (18.8% vs 0%, P = .04). Mutations in TP53 and CDKN2A were observed relatively frequently in SCCs with frequent hypermethylation (P = .02 for TP53 and P = .06 for CDKN2A). Survival analysis revealed that the SETD2 mutation was significantly associated with worse prognosis (P = .04). Collectively, we found frequent involvement of SETD2 and NFE2L2 mutations and MYC amplification in SCCs with IPF, and an association of a SETD2 mutation with poorer prognosis.

Kidney cancer is one of the most lethal cancer types worldwide. The most common subtype of kidney cancer is clear cell renal cell carcinoma (ccRCC), and the somatic mutations of ccRCC have been identified through the development of large databases. The present study aimed to validate the status of the associated gene mutations in a Taiwanese cohort. Targeted sequencing was used to validate the mutation status of genes related to ccRCC in Taiwanese patients who had nephrectomy for kidney cancer. The top eight mutated genes in the Catalogue Of Somatic Mutations In Cancer (COSMIC) were selected. These genes were VHL, protein polybromo-1 (PBRM1), histone-lysine N-methyltransferase SETD2, BRCA1-associated protein-1 (BAP1), lysine-specific demethylase 5C (KDM5C), TP53, MTOR and PTEN. The association between the gene mutation status of VHL, PBRM1, SETD2 and BAP1 was validated with clinicopathological parameters as well as overall survival time. Tumor cells from 96 patients with ccRCC were target sequenced. The order of mutation rate of the eight aforementioned genes was similar to that reported within COSMIC. The present Taiwanese cohort exhibited lower PBRM1 and BAP1 mutation rates compared with average, with increased mutation rates for SETD2 and KDM5C. BAP1 mutation was associated with the tumor and cancerous stage. None of these four genes were positively associated with the overall survival of patients. The PBRM1 and SETD2 mutations were mutually exclusive to BAP1 mutation. Overall, the present study provided data confirming gene alteration in Taiwanese patients with ccRCC and showed some differences when compared with Western countries. Further comprehensive genomic and epigenomic studies, as well as downstream validation, are necessary to evaluate the impact of these differences.

Background Recent studies have identified that glioblastoma IDH-wildtype (GBM IDH-WT) might be comprised of molecular subgroups with distinct prognoses. Therefore, we investigated the correlation between genetic alterations and survival in 282 GBM IDH-WT patients, to identify subgroups with distinct outcomes. Methods We reviewed characteristics of GBM IDH-WT (2009–2019) patients analyzed by next-generation sequencing interrogating 205 genes and 26 rearrangements. Progression-free survival (PFS) and overall survival (OS) were evaluated with the log-rank test and Cox regression models. We validated our results utilizing data from cBioPortal (MSK-IMPACT dataset). Results Multivariable analysis of GBM IDH-WT revealed that treatment with chemoradiation and RB1-mutant status correlated with improved PFS (hazard ratio [HR] 0.25, P < .001 and HR 0.47, P = .002) and OS (HR 0.24, P < .001 and HR 0.49, P = .016). In addition, younger age ( Conclusions RB1-mutant GBM IDH-WT is a molecular subgroup with improved PFS and OS. Meanwhile, 4q12 amplification (KDR/PDGFRA/KIT) denoted patients with worse OS. Identifying subgroups of GBM IDH-WT with distinct survival is important for optimal clinical trial design, incorporation of targeted therapies, and personalized neuro-oncological care.

This thesis was submitted for the degree of Master of Philosophy and awarded by Brunel University London Acute myeloid leukaemia (AML) is a blood disorder characterised by the proliferative behaviour and blocked myeloid differentiation. Despite years of intensive research, AML still has poor prognosis and have little therapeutic improvements. Aberrant epigenetic mechanism is a cornerstone of AML pathogenesis, and therapeutic agents that correct this dysregulation are intensively investigated for AML treatment. One of this is azacytidine, a DNA demethylating agent that is used for maintenance therapy or as alternative to abrasive chemotherapy. MAT2A has been previously characterised as a vulnerability gene in AML, and its inhibition resulted in poor maintenance and survival in AML cells. This study implicated, at the molecular level, the global reduction in DNA methylation, decrease in the SETD2-catalysed H3K36me3 and upregulation in the genes associated with the unfolded protein response (UPR), with the poor survival of AML cells. I therefore asked whether the effectiveness of DNA demethylation agent azacytidine can be extended in eliminating AML cells by combining it with SETD2 impairment and UPR activation. This has naturally led to two aims: (1) to downregulate the SETD2 expression using RNAi-mediated shRNA knockdown and (2) to combine azacytidine with the inhibitor of p97 (p97i), an important component of the endoplasmic reticulum-associated degradation (ERAD) and study their effects in AML cells. qPCR validation of the SETD2 shRNA knockdown failed to show downregulation of SETD2 in HEK293T cells and K562 cells, suggesting that further experimental troubleshooting should be carried out to obtain a valid SETD2 knockdown. On the other hand, treatment of AML cells with p97i impaired cell proliferation, increased the apoptosis and dysregulated the cell cycle regulation in the AML cell line MOLM-13. qRT-PCR analysis of p97i-treated AML cells exhibited an upregulation in the UPR chaperones DNAJB9, DNAJB11, DNAJC3 and CALR implying the induction of ER stress in these cells. Furthermore, the treatment of MOLM-13 cells with the combinations of a p97i named CB5083 and azacytidine exhibited more efficient termination of AML survival and propagation, both in conventional cell culture system and methylcellulose semi-solid media (CFC assay), than single treatment of azacytidine. This suggests that combinatorial targeting could be more favourable in terms of therapeutic option against AML. Collectively, these findings may have the potential to direct AML therapeutic options towards combinatorial targeting of the epigenetic modifications and anti-proliferative pathways for a more effective treatment against AML.

Both SETD2-mediated H3K36me3 and miRNAs play critical epigenetic roles in inflammatory bowel disease (IBD) and involve in the dysfunctional intestinal barrier. However, little is known about cross-talk between these two types of regulators in IBD progression. We performed small RNA sequencing of Setd2 epithelium-specific knockout mice (Setd2Vil-KO) and wild-type controls, both with DSS-induced colitis, and designed a framework for integrative analysis. Firstly, we integrated the downloaded ChIP-seq data with miRNA expression profiles and identified a significant intersection of pre-miRNA expression and H3K36me3 modification. A significant inverse correlation was detected between changes of H3K36me3 modification and expression of the 171 peak-covered miRNAs. We further integrated RNA-seq data with predicted miRNA targets to screen negatively regulated miRNA-mRNA pairs and found the H3K36me3-associated differentially expressed microRNAs significantly enriched in cell-cell junction and signaling pathways. Using network analysis, we identified ten hub miRNAs, among which six are H3K36me3-associated, suggesting therapeutic targets for IBD patients with SETD2-deficiency.

Histone modification stands for a vital genetic information form, which shows tight correlation with the modulation of normal physiological activities by genes. Abnormal regulation of histone methylation due to histone modification enzyme changes and histone mutations plays an important role in the development of cancer. Histone mutations, especially H3K27M and H3K36M, have been identified in various cancers such as pediatric DIPG (diffuse intrinsic pontine glioma) and chondroblastoma respectively. "K to M" mutation results overall downregulation of methylation on these lysine residues. Also, "K to M" mutant histones can inhibit the enzymatic activity of the responsible HMT (histone methyltransferase); for instance, SETD2 indicates H3K36 methylation, and Ezh2 represents H3K27 methylation. In-depth analysis of the mechanism of tumor formation triggered by the K to M mutation results in possible targeted therapies. This chapter is going to briefly introduce the mechanism of histone lysine-to-methionine mutation and review the recently identified targeted therapeutic strategies.

H3G34 mutations occur in both pediatric non-brainstem high-grade gliomas (G34R/V) and giant cell tumors of bone (G34W/L). Glioblastoma patients with G34R/V mutation have a generally adverse prognosis, whereas giant cell tumors of bone are rarely metastatic benign tumors. G34 mutations possibly disrupt the epigenome by altering H3K36 modifications, which may involve attenuating the function of SETD2 at methyltransferase. H3K36 methylation change may further lead to genomic instability, dysregulated gene expression pattern, and more mutations. In this chapter, we summarize the pathological features of each mutation type in its respective cancer, as well as the potential mechanism of their disruption on the epigenome and genomic instability. Understanding each mutation type would provide a thorough background for a thorough understanding of the cancers and would bring new insights for future investigations and the development of new precise therapies.

Primary bone tumors are rare cancers that cause significant morbidity and mortality. The recent identification of recurrent mutations in histone genes H3F3A and H3F3B within specific bone cancers, namely, chondroblastomas and giant cell tumors of bone (GCTB), has provided insights into the cellular and molecular origins of these neoplasms and enhanced understanding of how histone variants control chromatin function. Somatic mutations in H3F3A and H3F3B produce oncohistones, H3.3G34W and H3.3K36M, in more than nine of ten GCTB and chondroblastomas, respectively. Incorporation of the mutant histones into nucleosomes inhibits histone methyltransferases NSD2 and SETD2 to alter the chromatin landscape and change gene expression patterns that control cell proliferation, survival, and differentiation, as well as DNA repair and chromosome stability. The discovery of these histone mutations has facilitated more accurate diagnoses of these diseases and stratification of malignant tumors from benign tumors so that appropriate care can be delivered. The broad-scale epigenomic and transcriptomic changes that arise from incorporation of mutant histones into chromatin provide opportunities to develop new and disease-specific therapies. In this chapter, we review how mutant histones inhibit SETD2 and NSD2 function in bone tumors and discuss how this information could lead to better treatments for these cancers.

Simple Summary Monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL) is a rare primary T-cell lymphoma of the digestive tract that is characterized by an aggressive clinical course. The aim of this study was to analyze the clinicopathological characteristics and genomic profile of Asian MEITL. In this study, nine cases of Japanese MEITL were analyzed by targeted Next Generation Sequencing and immunohistochemistry and were integrated with previously reported whole-genome copy number microarray-based assay data. All cases showed alterations of the tumor suppressor gene SETD2 and mutations in one or more genes of the JAK/STAT pathway. Therefore, we concluded that the combination of epigenetic deregulation and cell signaling activation may represent a major oncogenic event in the pathogenesis of Asian MEITL, similar to Western MEITL. Abstract Monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL) is a rare primary T-cell lymphoma of the digestive tract derived from intraepithelial lymphocytes and characterized by an aggressive clinical course. In this study, nine cases of Japanese MEITL were analyzed by targeted Next Generation Sequencing (NGS) and immunohistochemistry and were integrated with previously reported whole-genome copy number microarray-based assay data. The highlight of our findings is that all cases showed alterations of the tumor suppressor gene SETD2 by mutations and/or loss of the corresponding 3p21 locus. We also demonstrated that all cases showed mutations in one or more genes of JAK/STAT pathway. Therefore, the combination of epigenetic deregulation and cell signaling activation represent major oncogenic events in the pathogenesis of MEITL in Asian MEITL, similar to Western MEITL.

Background The four most commonly-mutated genes in clear cell renal cell carcinoma (ccRCC) tumors are BAP1, PBRM1, SETD2 and VHL. And, there are currently 14 known RCC germline variants that have been reproducibly shown to be associated with RCC risk. However, the association of germline genetics with tumor genetics and clinical aggressiveness are unknown. Methods We analyzed 420 ccRCC patients from The Cancer Genome Atlas. Molecular subtype was determined based on acquired mutations in BAP1, PBRM1, SETD2 and VHL. Aggressive subtype was defined clinically using Mayo SSIGN score and molecularly using the ccA/ccB gene expression subtype. Publically-available Hi-C data were used to link germline risk variants with candidate target genes. Results The 8q24 variant rs35252396 was significantly associated with VHL mutation status (OR = 1.6, p = 0.0037) and SSIGN score (OR = 1.9, p = 0.00094), after adjusting for multiple comparisons. We observed that, while some germline variants have interactions with nearby genes, some variants demonstrate long-range interactions with target genes. Conclusions These data further demonstrate the link between rs35252396, HIF pathway and ccRCC clinical aggressiveness, providing a more comprehensive picture of how germline genetics and tumor genetics interact with respect to tumor development and progression.

Background and aims Trimethylation of Lys36 on histone 3 (H3K36me3) catalyzed by histone methyltransferase SET domain-containing 2 (SETD2) is one of the most conserved epigenetic marks from yeast to mammals. SETD2 is frequently mutated in multiple cancers and acts as a tumor suppressor. Approach and results Here, using a liver-specific Setd2 depletion model, we found that Setd2 deficiency is sufficient to trigger spontaneous HCC. Meanwhile, Setd2 depletion significantly increased tumor and tumor size of a diethylnitrosamine-induced HCC model. The mechanistic study showed that Setd2 suppresses HCC not only through modulating DNA damage response, but also by regulating lipid metabolism in the liver. Setd2 deficiency down-regulated H3K36me3 enrichment and expression of cholesterol efflux genes and caused lipid accumulation. High-fat diet enhanced lipid accumulation and promoted the development of HCC in Setd2-deficient mice. Chromatin immunoprecipitation sequencing analysis further revealed that Setd2 depletion induced c-Jun/activator protein 1 (AP-1) activation in the liver, which was trigged by accumulated lipid. c-Jun acts as an oncogene in HCC and functions through inhibiting p53 in Setd2-deficient cells. Conclusions We revealed the roles of Setd2 in HCC and the underlying mechanisms in regulating cholesterol homeostasis and c-Jun/AP-1 signaling.

An outgrowth of therapy-resistant prostate cancers (PCa) with enhanced metastatic potential may be triggered by inhibitors of androgen receptor (AR) signalling, often via epigenetic rewiring. In this issue of Cancer Cell, Yuan et al. demonstrate how SETD2 integrates EZH2 and AMPK signalling pathways to keep PCa metastasis in check.

SETD2 is the only methyltransferase for H3K36me3, and our previous study has firstly demonstrated that it functioned as one tumor suppressor in hematopoiesis. Consistent with it, SETD2 mutation, which led to its loss of function, was identified in AML. However, the distribution and function of SETD2 mutation in AML remained largely unknown. Herein, we integrated SETD2-mutated AML cases from our center and literature reports, and found that NPM1 mutation was the most common concomitant genetic alteration with SETD2 mutation in AML, with its frequency even higher than MLL rearrangement and AML1-ETO. Though this result indicated the cooperation of SETD2 and NPM1 mutations in leukemogenesis, our functional study showed that SETD2 was required for the proliferation of NPM1-mutated AML cell line OCI-AML3, but not MLL-rearranged AML cell line THP-1, via maintaining its direct target NPM1 expression, which was just opposite to its role of tumor suppressor. Therefore, we speculated that SETD2 possibly had two different faces in distinct subtypes and stages of AML.

The process of autophagy is dysregulated in many cancers including clear cell renal cell carcinoma (ccRCC). Autophagy involves the coordination of numerous autophagy-related (ATG) genes, as well as processes involving the actin cytoskeleton. The histone methyltransferase SETD2, frequently inactivated in ccRCC, has recently been shown to also methylate cytoskeletal proteins, which in the case of actin lysine 68 trimethylation (ActK68me3) regulates actin polymerization dynamics. Here we show that cells lacking SETD2 exhibit autophagy defects, as well as decreased interaction of the actin nucleation promoting factor WHAMM with its target actin, which is required for initiation of autophagy. Interestingly, the WHAMM actin binding deficit could be rescued with pharmacologic induction of actin polymerization in SETD2-null cells using Jasplakinolide. These data indicate that the decreased interaction between WHAMM and its target actin in SETD2-null cells was secondary to altered actin dynamics rather than loss of the SETD2 ActK68me3 mark itself, and underscores the importance of the functional defect in actin polymerization in SETD2-null cells exhibiting autophagy defects.

Pseudomyxoma peritonei(PMP) is a rare disorder with unique pathological and genetic changes. Although several studies have reported the clinical features and mutational changes of PMP that originates from the appendix, few studies on PMP originating from the ovary have been reported due to its extreme rarity. In order to characterize the somatic mutational landscape and to investigate the prognosis predicting factors of ovary-originating PMP, we examined 830 cases of PMP and identified 16 patients with PMP that originated from the ovary. Whole-exome sequencing(WES) was performed on 12 cases using formalin-fixed, paraffin-embedded(FFPE) tissue samples. We found that 25%(3/12) of the patients carried mutations in cancer driver genes, including TP53, ATM and SETD2,and 16.7%(2/12) of the patients carried mutations in cancer driver genes, including ATRX, EP300, FGFR2, KRAS, NOCR1, and RB1. The MUC16(58.33%), BSN(41.67%), PCNT(41.67%), PPP2R5A(41.67%), PRSS36(41.67%), PTPRK(41.67%),and SBF1(41.67%) genes presented the highest mutational frequencies. The PI3K-Akt signaling pathway, human papillomavirus infection pathway, cell skeleton, cell adhesion, and extracellular matrix and membrane proteins were the major pathways or functions that were affected. Patients were followed up to 174 months(median: 48.26 months). The 5-year OS rate for all patients was 71.2% and the median OS was not reached. PTPRK mutations, pre-surgical CA199 level, completeness of cytoreduction(CCR) and peritoneal cancer index(PCI) were identified as potential predictive factors for patient survival. In conclusion, the mutational landscape for ovary-originating PMP was revealed and exhibited unique features distinct from appendix-originating PMP. PTPRK, CA199, CCR and PCI may predict patient survival. This article is protected by copyright. All rights reserved.

SUMMARYHeterogeneous ribonucleoproteins (hnRNPs) are RNA binding molecules that are involved in key processes such as RNA splicing and transcription. One such hnRNP protein, hnRNP L, regulates alternative splicing (AS) by binding to pre-mRNA transcripts. However, it is unclear what factors contribute to hnRNP L-regulated AS events. Using proteomic approaches, we identified several key factors that co-purify with hnRNP L. We demonstrate that one such factor, the histone methyltransferase SETD2, specifically interacts with hnRNP Lin vitroandin vivo. This interaction occurs through a previously uncharacterized domain in SETD2, the SETD2-hnRNP L Interaction (SHI) domain, the deletion of which, leads to a reduced H3K36me3 deposition. Functionally, SETD2 regulates a subset of hnRNP L-targeted AS events. Our findings demonstrate that SETD2 by interacting with Pol II as well as hnRNP L, can mediate the crosstalk between the transcription and the splicing machinery.

Background The histone H3K36me3 mark regulates transcription elongation, pre-mRNA splicing, DNA methylation, and DNA damage repair. However, knowledge of the regulation of the enzyme SETD2, which deposits this functionally important mark, is very limited. Results Here, we show that the poorly characterized N-terminal region of SETD2 plays a determining role in regulating the stability of SETD2. This stretch of 1–1403 amino acids contributes to the robust degradation of SETD2 by the proteasome. Besides, the SETD2 protein is aggregate prone and forms insoluble bodies in nuclei especially upon proteasome inhibition. Removal of the N-terminal segment results in the stabilization of SETD2 and leads to a marked increase in global H3K36me3 which, uncharacteristically, happens in a Pol II-independent manner. Conclusion The functionally uncharacterized N-terminal segment of SETD2 regulates its half-life to maintain the requisite cellular amount of the protein. The absence of SETD2 proteolysis results in a Pol II-independent H3K36me3 deposition and protein aggregation.

Summary Conventional chordoma is a rare slow-growing malignant tumor of notochordal origin primarily arising at the base of the skull and sacrococcygeal bones. Chordoma may arise from its benign counterpart, benign notochordal cell tumors, and can also undergo dedifferentiation progressing into dedifferentiated chordoma. No study has directly compared the genomic alterations among these tumors comprising a morphologic continuum. Our prior study identified frequent chromosome 3p loss of heterozygosity and minimal deleted regions on chromosome 3 encompassing SETD2, encoding a histone methyltransferase involved in histone H3 lysine 36 trimethylation (H3K36me3). In the present study, we expanded our study to include 65 sacral conventional chordoma cases, 3 benign notochordal cell tumor cases, and 2 dedifferentiated chordoma cases using single nucleotide polymorphism (SNP) array, targeted next-generation sequencing analysis, and immunohistochemistry. We performed immunohistochemical analysis of histone, H3K36me3, and investigated whether there is any association between the clinical behavior and recurrent chromosome or aneuploidy or H3K36me3 protein expression. We found that there is increased genomic instability from benign notochordal cell tumor to conventional chordoma to dedifferentiated chordoma. The highly recurrent genomic aberration, chromosome 3p loss of heterozygosity (occurred in 70% of conventional chordomas), is correlated with longer relapse-free survival, but not with overall survival or metastasis-free survival in sacral chordoma. Chordomas demonstrate variable patterns and levels of H3K36me3 expression, and reduced expression of H3K36me3 showed marginally significant correlation with longer relapse-free survival. Copy number alterations in the genes encoding the H3K36me3 methylation transferase complex and demethylase may account for the altered H3K36me3 expression levels.

Cancer genome sequencing has uncovered substantial complexity in the mutational landscape of tumors. Given this complexity, experimental approaches are necessary to establish the impact of combinations of genetic alterations on tumor biology and to uncover genotype-dependent effects on drug sensitivity. In lung adenocarcinoma, EGFR mutations co-occur with many putative tumor suppressor gene alterations, however the extent to which these alterations contribute to tumor growth and their response to therapy in vivo has not been explored experimentally. By integrating a novel mouse model of oncogenic EGFR-driven Trp53-deficient lung adenocarcinoma with multiplexed CRISPR–Cas9-mediated genome editing and tumor barcode sequencing, we quantified the effects of inactivation of ten putative tumor suppressor genes. Inactivation of Apc, Rb1, or Rbm10 most strongly promoted tumor growth. Unexpectedly, inactivation of Lkb1 or Setd2 – which are the strongest drivers of tumor growth in an oncogenic Kras-driven model – reduced EGFR-driven tumor growth. These results are consistent with the relative frequency of these tumor suppressor gene alterations in human EGFR- and KRAS-driven lung adenocarcinomas. Furthermore, Keap1 inactivation reduces the sensitivity of EGFR-driven Trp53-deficient tumors to the EGFR inhibitor osimertinib. Importantly, in human EGFR/TP53 mutant lung adenocarcinomas, mutations in the KEAP1 pathway correlated with decreased time on tyrosine kinase inhibitor treatment. Our study highlights how genetic alterations can have dramatically different biological consequences depending on the oncogenic context and that the fitness landscape can shift upon drug treatment.