Project description:Genome-wide studies characterizing mutational landscape of bladder cancer revealed the exceptionally high rate of chromatin modifier genes in bladder cancer. Thus, epigenetic deregulation is a critical theme which needs further investigation for bladder cancer research. One of the highly mutated genes in bladder cancer is KDM6A, functioning as H3K27 demethylase and part of MLL3/4 complexes. To decipher the role of KDM6A in normal vs tumor setting, we identified the genomic localization profiles of KDM6A in normal, immortalized and cancer bladder cells. Our results showed differential occupancy of KDM6A at the genes involved in cell differentiation, chromatin organization and Notch signaling depending on the cell type and the mutation status of KDM6A. Transcription factor motif analysis revealed an enrichment for HES1 for the KDM6A peaks identified for T24 bladder cancer cell line, which has a truncating mutation in KDM6A and lacking demethylase domain and also for the other clusters showing KDM6A localization. For the first time, using co-immunoprecipitation experiments, we show that KDM6A is in complex with TLE co-repressors and HES1, and illustrate the potential interaction of KDM6A with TLE co-repressors, HES1, RUNX, HHEX transcription factors by computational structural biology models. Our work makes important contributions to the understanding of KDM6A malfunction in bladder cancer and provides models for the functioning of KDM6A independent of its demethylase activity.
2023-03-03 | GSE216625 | GEO
Project description:KDM6A mutation in mouse model of bladder cancer
Project description:Purpose: The goals of this study are to compare 1. The transcription profile in KDM6A wildtype and KDM6A mutated urothelial bladder carcinoma. 2. The transcriptional changes in KDM6A mutated urothelial bladder carcinoma upon EZH2 inhibitor treatment.
Project description:RXRA regulates transcription as part of a heterodimer with 14 other nuclear receptors, including the peroxisome proliferator-activated receptors (PPARs). Analysis from the TCGA raised the possibility that hyperactive PPAR signaling, either due to PPAR gamma gene amplification or RXRA hot-spot mutation (S427F/Y) drives 20-25% of bladder cancers. Here we characterize mutant RXRA, demonstrating it induces enhancer/promoter activity in the context of RXRA/PPAR heterodimers. Structure-function studies indicate the RXRA substitution allosterically regulates the PPAR AF2 domain via an aromatic interaction with the terminal tyrosine found in PPARs. In urothelium, we find PPAR agonism is sufficient to drive growth factor independent growth, but only after deletion of the tumor suppressors Kdm6a and Trp53. Similarly, mutant RXRA stimulates growth factor independent growth, in a manner reversible by PPAR inhibition. These studies reveal a pro-tumorigenic interaction between loss of tumor suppressors and PPAR activation and implicate PPARs as targetable drivers of bladder cancer.
Project description:Acute Promyelocytic Leukemia (APL) is characterized by the t(15;17)(q22;q11.2) translocation, which creates a PML-RARA fusion gene that can initiate APL in mice. To discover cooperating mutations in this model, we sequenced a mouse APL genome to 15.6x haploid coverage, and discovered three somatic, non-synonymous mutations, of which one (Jak1 V657F) was recurrent. This mutation is identical to the JAK1 V658F mutation previously found in human APL and ALL samples. JAK1 V658F cooperates in vivo with PML-RARA, causing a rapidly fatal leukemia. We also discovered a somatic 150kb deletion involving the Kdm6a/Utx gene in the mouse APL genome; 3/14 additional mouse APL samples had similar deletions involving Kdm6a/Utx. Kdm6A/Utx, a histone H3K27 demethylase, was also deleted in 1/150 human AML samples tested. Whole genome sequencing of mouse cancer genomes provides an unbiased approach for discovering functionally relevant mutations that are also present in human leukemias. Spleens from Bl/6 Taconic mice were harvested and total RNA was extracted. A total of 15 specimens were analyzed using the Affymetrix Mouse Exon 1.0 ST platform.
Project description:Acute Promyelocytic Leukemia (APL) is characterized by the t(15;17)(q22;q11.2) translocation, which creates a PML-RARA fusion gene that can initiate APL in mice. To discover cooperating mutations in this model, we sequenced a mouse APL genome to 15.6x haploid coverage, and discovered three somatic, non-synonymous mutations, of which one (Jak1 V657F) was recurrent. This mutation is identical to the JAK1 V658F mutation previously found in human APL and ALL samples. JAK1 V658F cooperates in vivo with PML-RARA, causing a rapidly fatal leukemia. We also discovered a somatic 150kb deletion involving the Kdm6a/Utx gene in the mouse APL genome; 3/14 additional mouse APL samples had similar deletions involving Kdm6a/Utx. Kdm6A/Utx, a histone H3K27 demethylase, was also deleted in 1/150 human AML samples tested. Whole genome sequencing of mouse cancer genomes provides an unbiased approach for discovering functionally relevant mutations that are also present in human leukemias.
Project description:Bladder cancer prognosis is closely linked to the underlying differentiation state of the tumor, ranging from the less aggressive and most differentiated luminal tumors to the more aggressive and least differentiated basal tumors. Sequencing of bladder cancer has revealed that loss-of-function mutations in chromatin regulators and mutations that activate receptor tyrosine kinase (RTK) signaling frequently occur in bladder cancer. However, little is known as to whether and how these two types of mutations functionally interact or cooperate to regulate tumor growth and differentiation state. Here, we focus on loss of the histone demethylase UTX (also known as KDM6A) and activation of the RTK FGFR3, two events that commonly co-occur in muscle invasive bladder tumors. We show that UTX loss and FGFR3 activation cooperate to disrupt the balance of luminal and basal gene expression in bladder cells. UTX localized to enhancers surrounding many genes that are important for luminal cell fate, and supported the transcription of these genes in a catalytic-independent manner. In contrast to UTX, FGFR3 activation was associated with lower expression of luminal genes in tumors and FGFR inhibition increased transcription of these same genes in cell culture models. This suggests an antagonistic relationship between UTX and FGFR3. In support of this model, UTX loss-of-function potentiated FGFR3-dependent transcriptional effects and the presence of UTX blocked an FGFR3-mediated increase in the colony formation of bladder cells. Taken together, our study reveals how mutations in UTX and FGFR3 converge to disrupt bladder differentiation programs that could serve as a therapeutic target.
Project description:RXRA regulates transcription as part of a heterodimer with 14 other nuclear receptors, including the peroxisome proliferator-activated receptors (PPARs). Analysis from the TCGA raised the possibility that hyperactive PPAR signaling, either due to PPAR gamma gene amplification or RXRA hot-spot mutation (S427F/Y) drives 20-25% of bladder cancers. Here we characterize mutant RXRA, demonstrating it induces enhancer/promoter activity in the context of RXRA/PPAR heterodimers. Structure-function studies indicate the RXRA substitution allosterically regulates the PPAR AF2 domain via an aromatic interaction with the terminal tyrosine found in PPARs. In urothelium, we find PPAR agonism is sufficient to drive growth factor independent growth, but only after deletion of the tumor suppressors Kdm6a and Trp53. Similarly, mutant RXRA stimulates growth factor independent growth, in a manner reversible by PPAR inhibition. These studies reveal a pro-tumorigenic interaction between loss of tumor suppressors and PPAR activation and implicate PPARs as targetable drivers of bladder cancer.
Project description:Acute myeloid leukemia (AML) is an aggressive hematologic neoplasm resulting from the malignant transformation of myeloid progenitors. Despite intensive chemotherapy leading to initial treatment responses, relapse caused by intrinsic or acquired drug resistance represents a major challenge. Here, we report that histone 3 lysine 27 demethylase KDM6A (UTX) is targeted by inactivating mutations and mutation-independent regulation in relapsed AML. Analyses of matched diagnosis and relapse specimens from individuals with KDM6A mutations showed an outgrowth of the KDM6A mutated tumor population at relapse. KDM6A-null myeloid leukemia cells were more resistant to treatment with the chemotherapeutic agents cytarabine (AraC) and daunorubicin. Inducible re-expression of KDM6A in KDM6A-null cell lines suppressed proliferation and sensitized cells again to AraC treatment. RNA expression analysis and functional studies revealed that resistance to AraC was conferred by downregulation of the nucleoside membrane transporter ENT1 (SLC29A1). Our results show that loss of KDM6A provides cells with a selective advantage during chemotherapy, which ultimately leads to the observed outgrowth of clones with KDM6A mutations or reduced KDM6A expression at relapse.
Project description:Acute myeloid leukemia (AML) is an aggressive hematologic neoplasm resulting from the malignant transformation of myeloid progenitors. Despite intensive chemotherapy leading to initial treatment responses, relapse caused by intrinsic or acquired drug resistance represents a major challenge. Here, we report that histone 3 lysine 27 demethylase KDM6A (UTX) is targeted by inactivating mutations and mutation-independent regulation in relapsed AML. Analyses of matched diagnosis and relapse specimens from individuals with KDM6A mutations showed an outgrowth of the KDM6A mutated tumor population at relapse. KDM6A-null myeloid leukemia cells were more resistant to treatment with the chemotherapeutic agents cytarabine (AraC) and daunorubicin. Inducible re-expression of KDM6A in KDM6A-null cell lines suppressed proliferation and sensitized cells again to AraC treatment. RNA expression analysis and functional studies revealed that resistance to AraC was conferred by downregulation of the nucleoside membrane transporter ENT1 (SLC29A1). Our results show that loss of KDM6A provides cells with a selective advantage during chemotherapy, which ultimately leads to the observed outgrowth of clones with KDM6A mutations or reduced KDM6A expression at relapse.