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RNA-seq Series of Bladder Carcinoma Tumors

ABSTRACT: Background: Muscle-invasive bladder cancer is a common aggressive disease with unmet clinical needs. Recent work established a set of consensus bladder cancer transcriptomic subtypes that distinguishes the cell identity of bladder cancers for improved diagnosis and treatment. However, how these distinct subtypes are regulated remains unclear. Given the link between super-enhancers and the regulation of cell identity, we hypothesized that epigenetic activation of distinct super-enhancers could drive the transcriptional programs of the various bladder cancer subtypes. Results: Through integrated RNA sequencing and epigenomic profiling of histone marks (H3K27ac, H3K27me3, H3K9me3) in a diverse panel of 15 primary bladder tumours, seven bladder cancer cell lines, and two primary cultures from normal human urothelia, we established the first integrated epigenetic map of bladder cancer and demonstrate the link between bladder cancer subtype and epigenetic control. Through H3K27ac analysis, we identify the repertoire of activated super-enhancers in bladder cancer that distinguish molecular subtypes. Building on these findings, we reveal the super-enhancer-regulated networks of candidate master transcription factors for Luminal and Basal bladder cancer subgroups. We find that FOXA1, a key pioneer factor in Luminal bladder cancers identified in our Luminal transcription factor network, binds subgroup-specific bladder super-enhancers and correlates with their activation. Furthermore, CRISPR-Cas9 inactivating mutation of FOXA1 triggers a shift from Luminal to Basal cell identity. This shift is accompanied by an overexpression of ZBED2, one of the newly identified transcriptional regulators in the Basal-specific transcription factor network. 5Finally, we show that both FOXA1 and ZBED2 play concordant roles in preventing inflammatory response in bladder cancer cells through STAT2 inhibition and promote cancer cell survival. Conclusions: Overall, our study provides new data for understanding epigenetic regulation of muscle- invasive bladder cancer and identifies a coregulated network of super-enhancers and associated transcription factors as new potential targets for the treatment of this aggressive disease

ORGANISM(S): Homo sapiens

PROVIDER: GSE195768 | GEO | 2024/05/23

REPOSITORIES: GEO

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Project description:Background: Muscle-invasive bladder cancer is a common aggressive disease with unmet clinical needs. Recent work established a set of consensus bladder cancer transcriptomic subtypes that distinguishes the cell identity of bladder cancers for improved diagnosis and treatment. However, how these distinct subtypes are regulated remains unclear. Given the link between super-enhancers and the regulation of cell identity, we hypothesized that epigenetic activation of distinct super-enhancers could drive the transcriptional programs of the various bladder cancer subtypes. Results: Through integrated RNA sequencing and epigenomic profiling of histone marks (H3K27ac, H3K27me3, H3K9me3) in a diverse panel of 15 primary bladder tumours, seven bladder cancer cell lines, and two primary cultures from normal human urothelia, we established the first integrated epigenetic map of bladder cancer and demonstrate the link between bladder cancer subtype and epigenetic control. Through H3K27ac analysis, we identify the repertoire of activated super-enhancers in bladder cancer that distinguish molecular subtypes. Building on these findings, we reveal the super-enhancer-regulated networks of candidate master transcription factors for Luminal and Basal bladder cancer subgroups. We find that FOXA1, a key pioneer factor in Luminal bladder cancers identified in our Luminal transcription factor network, binds subgroup-specific bladder super-enhancers and correlates with their activation. Furthermore, CRISPR-Cas9 inactivating mutation of FOXA1 triggers a shift from Luminal to Basal cell identity. This shift is accompanied by an overexpression of ZBED2, one of the newly identified transcriptional regulators in the Basal-specific transcription factor network. 5Finally, we show that both FOXA1 and ZBED2 play concordant roles in preventing inflammatory response in bladder cancer cells through STAT2 inhibition and promote cancer cell survival. Conclusions: Overall, our study provides new data for understanding epigenetic regulation of muscle- invasive bladder cancer and identifies a coregulated network of super-enhancers and associated transcription factors as new potential targets for the treatment of this aggressive disease

Project description:Breast cancer is a heterogeneous disease comprised of at least five major subtypes. Luminal subtype tumors confer a more favourable patient prognosis, which is in part, attributed to the Estrogen Receptor-alpha (ER) positivity and anti-hormone responsiveness of these tumors. Expression of the forkhead box transcription factor, FOXA1, also correlates with the luminal subtype and patient survival, but is present in a subset of ER-negative tumors. Similarly, FOXA1 is consistently expressed in luminal breast cancer cell lines even in the absence of ER. In contrast, basal breast cancer cell lines do not express FOXA1, and loss of FOXA1 in luminal cells increases migration and invasion, characteristics of the basal subtype. To delineate an ER-independent role for FOXA1 in maintaining the luminal phenotype, and hence a more favourable prognosis, we performed cDNA microarray analyses on luminal FOXA1-positive, ER-positive (MCF7, T47D) and FOXA1-positive, ER-negative (MDA-MB-453, SKBR3) cell lines in the presence or absence of transient FOXA1 silencing. This resulted in three FOXA1 transcriptomes: (1) a luminal-signature (consistent across cell lines), (2) an ER-positive signature (restricted to MCF7 and T47D) and (3) an ER-negative signature (restricted to MDA-MB-453 and SKBR3). Use of Gene Set Enrichment Analyses (GSEA) as a phenotyping tool revealed that FOXA1 silencing resulted in a transcriptome shift from luminal to basal gene expression signatures. FOXA1 binds to both luminal and basal genes within luminal breast cancer cells, suggesting that it not only transactivates luminal genes, but also represses basal-associated genes. From these results we conclude that FOXA1 controls plasticity between basal and luminal cells, playing a dominant role in repressing the basal phenotype, and thus tumor aggressiveness, in luminal breast cancer cells. Although it has been proposed that FOXA1-targeting agents may be useful for treating luminal tumors, these data suggest that this approach may promote transitions toward a more aggressive cancer. FOXA1 siRNA treated breast cell lines compared directly to nonspecific siRNA treated cell lines using Agilent 4X44 microarrays.

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RNA-seq Series of Bladder Carcinoma Tumors

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