Project description:Pancreatic ductal adenocarcinoma (PDAC) remains a highly lethal cancer with a 5-year survival rate of 13%. Despite recent molecular stratification of tumors into distinct classical and basal-like cell states, most tumors are heterogeneous contain of both subtypes. Therefore, therapeutic approaches targeting one subtype may not be suitable for PDAC therapy. Here, we integrated chromatin accessibility (ATAC-seq), genome-wide occupancy (ChIP-seq) for epigenetic status (H3K27ac) and H3K4me3-anchored chromatin topology (HiChIP) to uncover subtype-independent highly interactive enhancers that interact with essential genes in PDAC. Motif analysis revealed these common enhancers were bound by KLF5 with subsequent depletion leading to decreased cell viability via induction of apoptosis. To elucidate the transcriptional and epigenetic mechanisms by which KLF5 functions in PDAC, we employed rapid depletion of KLF5 with dTAG technology and profiled the effects on the open and active chromatin landscape and transcription with nascent RNA and mRNA-seq over time. Enhancer inactivation via KRAB domain Zim3-dCas9 fusion protein confirmed KLF5-bound enhancers regulate target genes, including the anti-apoptotic gene BCL2L1. Multiplex immunofluorescence confirmed co-staining of KLF5 and Bcl-xL in patient samples and overexpression of Bcl-xL rescued the induction of apoptosis after KLF5 depletion. Taken together, this study provides new insights into common mechanisms to target highly heterogeneous PDAC tumors.
Project description:Pancreatic ductal adenocarcinoma (PDAC) remains a highly lethal cancer with a 5-year survival rate of 13%. Despite recent molecular stratification of tumors into distinct classical and basal-like cell states, most tumors are heterogeneous contain of both subtypes. Therefore, therapeutic approaches targeting one subtype may not be suitable for PDAC therapy. Here, we integrated chromatin accessibility (ATAC-seq), genome-wide occupancy (ChIP-seq) for epigenetic status (H3K27ac) and H3K4me3-anchored chromatin topology (HiChIP) to uncover subtype-independent highly interactive enhancers that interact with essential genes in PDAC. Motif analysis revealed these common enhancers were bound by KLF5 with subsequent depletion leading to decreased cell viability via induction of apoptosis. To elucidate the transcriptional and epigenetic mechanisms by which KLF5 functions in PDAC, we employed rapid depletion of KLF5 with dTAG technology and profiled the effects on the open and active chromatin landscape and transcription with nascent RNA and mRNA-seq over time. Enhancer inactivation via KRAB domain Zim3-dCas9 fusion protein confirmed KLF5-bound enhancers regulate target genes, including the anti-apoptotic gene BCL2L1. Multiplex immunofluorescence confirmed co-staining of KLF5 and Bcl-xL in patient samples and overexpression of Bcl-xL rescued the induction of apoptosis after KLF5 depletion. Taken together, this study provides new insights into common mechanisms to target highly heterogeneous PDAC tumors.
Project description:Pancreatic ductal adenocarcinoma (PDAC) remains a highly lethal cancer with a 5-year survival rate of 13%. Despite recent molecular stratification of tumors into distinct classical and basal-like cell states, most tumors are heterogeneous contain of both subtypes. Therefore, therapeutic approaches targeting one subtype may not be suitable for PDAC therapy. Here, we integrated chromatin accessibility (ATAC-seq), genome-wide occupancy (ChIP-seq) for epigenetic status (H3K27ac) and H3K4me3-anchored chromatin topology (HiChIP) to uncover subtype-independent highly interactive enhancers that interact with essential genes in PDAC. Motif analysis revealed these common enhancers were bound by KLF5 with subsequent depletion leading to decreased cell viability via induction of apoptosis. To elucidate the transcriptional and epigenetic mechanisms by which KLF5 functions in PDAC, we employed rapid depletion of KLF5 with dTAG technology and profiled the effects on the open and active chromatin landscape and transcription with nascent RNA and mRNA-seq over time. Enhancer inactivation via KRAB domain Zim3-dCas9 fusion protein confirmed KLF5-bound enhancers regulate target genes, including the anti-apoptotic gene BCL2L1. Multiplex immunofluorescence confirmed co-staining of KLF5 and Bcl-xL in patient samples and overexpression of Bcl-xL rescued the induction of apoptosis after KLF5 depletion. Taken together, this study provides new insights into common mechanisms to target highly heterogeneous PDAC tumors.
Project description:Pancreatic ductal adenocarcinoma (PDAC) remains a highly lethal cancer with a 5-year survival rate of 13%. Despite recent molecular stratification of tumors into distinct classical and basal-like cell states, most tumors are heterogeneous contain of both subtypes. Therefore, therapeutic approaches targeting one subtype may not be suitable for PDAC therapy. Here, we integrated chromatin accessibility (ATAC-seq), genome-wide occupancy (ChIP-seq) for epigenetic status (H3K27ac) and H3K4me3-anchored chromatin topology (HiChIP) to uncover subtype-independent highly interactive enhancers that interact with essential genes in PDAC. Motif analysis revealed these common enhancers were bound by KLF5 with subsequent depletion leading to decreased cell viability via induction of apoptosis. To elucidate the transcriptional and epigenetic mechanisms by which KLF5 functions in PDAC, we employed rapid depletion of KLF5 with dTAG technology and profiled the effects on the open and active chromatin landscape and transcription with nascent RNA and mRNA-seq over time. Enhancer inactivation via KRAB domain Zim3-dCas9 fusion protein confirmed KLF5-bound enhancers regulate target genes, including the anti-apoptotic gene BCL2L1. Multiplex immunofluorescence confirmed co-staining of KLF5 and Bcl-xL in patient samples and overexpression of Bcl-xL rescued the induction of apoptosis after KLF5 depletion. Taken together, this study provides new insights into common mechanisms to target highly heterogeneous PDAC tumors.
Project description:Three transcription factors KLF5, GATA4 and GATA6 are recurrently amplified in multiple gastric cancer cohorts, representing one type of lineage-survival oncogenes in gastric cancer. ChIP-Seq analysis of these three factors in multiple cell lines revealed that significant number of genomic sites are co-occupied by KLF5 and GATA4 and/or GATA6. Integrative analysis of ChIP-Seq and gene expression identified several targets of the three transcription factors in both cell lines and primary tumors, including HNF4A. These results suggest that KLF5, GATA4 and GATA6 interact and co-operate to regulate HNF4A and other genes to promote tumorigenesis in gastric cancer. Gene expression profiling of KLF5, GATA4 and GATA6 knock down in YCC3/AGS/KATOIII cells
Project description:Three transcription factors KLF5, GATA4 and GATA6 are recurrently amplified in multiple gastric cancer cohorts, representing one type of lineage-survival oncogenes in gastric cancer. ChIP-Seq analysis of these three factors in multiple cell lines revealed that significant number of genomic sites are co-occupied by KLF5 and GATA4 and/or GATA6. Integrative analysis of ChIP-Seq and gene expression identified several targets of the three transcription factors in both cell lines and primary tumors, including HNF4A. These results suggest that KLF5, GATA4 and GATA6 interact and co-operate to regulate HNF4A and other genes to promote tumorigenesis in gastric cancer. ChIP-Seq experiments of KLF5, GATA4 and GATA6 were performed in three gastric cancer cell lines YCC3, AGS and KATOIII
Project description:<p>Non-coding elements in our genomes that play critical roles in complex disease are frequently marked by highly unstable RNA species. Sequencing nascent RNAs attached to an actively transcribing RNA polymerase complex can identify unstable RNAs, including those templated from gene-distal enhancers (eRNAs). However, nascent RNA sequencing techniques remain challenging to apply in some cell lines and especially to intact tissues, limiting broad applications in fields such as cancer genomics and personalized medicine. Here we report the development of chromatin run-on and sequencing (ChRO-seq), a novel run-on technology that maps the location of RNA polymerase using virtually any frozen tissue sample, including samples with degraded RNA that are intractable to conventional RNA-seq. We used ChRO-seq to develop the first maps of nascent transcription in 23 human glioblastoma (GBM) brain tumors and patient derived xenografts. Remarkably, >90,000 distal enhancers discovered using the signature of eRNA biogenesis within primary GBMs closely resemble those found in the normal human brain, and diverge substantially from GBM cell models. Despite extensive overall similarity, 12% of enhancers in each GBM distinguish normal and malignant brain tissue. These enhancers drive regulatory programs similar to the developing nervous system and are enriched for transcription factor binding sites that specify a stem-like cell fate. These results demonstrate that GBMs largely retain the enhancer landscape associated with their tissue of origin, but selectively adopt regulatory programs that are responsible for driving stem-like cell properties. We also identified enhancers and their associated transcription factors that regulate genes characteristic of each known GBM subtype, and discovered a core group of transcription factors that control the expression of genes associated with clinical outcomes. This study uncovers new insights into the molecular etiology of GBM and introduces ChRO-seq which can now be used to map regulatory programs contributing to a variety of complex diseases.</p>
Project description:Activation of the Ras/Erk pathway upregulates expression of the Kruppel-like Factor 5 (KLF5) transcription factor, and KLF5 is a downstream mediator of Ras oncogenic signaling. Specifically, in bladder and colon cancer cell lines KLF5 upregulates the Ras-pathway target gene cyclin D1, and facilitates entry into the S phase of the cell cycle. Ras mutations are common in lung cancer, but a role for KLF5 in lung tumorigenesis has not been defined. To this end, we manipulated KLF5 expression in four Ras-mutant human lung adenocarcinoma cell lines to find that KLF5 significantly modulates anchorage-independent growth, a mutant Ras phenotype. However, in a mouse model of human lung adenocarcinoma, K-RasG12D does not critically require Klf5 to mediate oncogenesis or induce cyclin D1 expression. Patients with lung tumors expressing high levels of KLF5 have significantly better prognosis than those with low or no KLF5 expression (opposite of mutant Ras prognosis). The latter may be explained by KLF5 transcriptional repression of the ATP-binding cassette, sub-family G (WHITE), member 2 (ABCG2), an anthracycline transporter. In agreement with this, KLF5 knockdown cells display significantly more Hoechst â??side populationâ?? and resistance to doxorubicin. In summary, while KLF5 is not an obligate partner in Ras oncogenic signaling, KLF5 control of ABCG2 expression is significant to patient survival. Experiment Overall Design: Total RNA was extracted from H441 cells transduced with KLF5-specific shRNA (KD), KLF5 over expression (OE) and MSCV empty vertor (NT) respectively. The cRNAs was then hybridized to Human Genome U133 Plus 2.0 Arrays (Affymetrix) according to manufacturerâ??s protocol.
Project description:The transcription factor KLF5 is highly expressed in basal-like breast cancer (BLBC). It promotes cell proliferation, survival, migration and stemness and serves as a potential therapeutic target. In this study, we first identified a super-enhancer (SE) located downstream of the KLF5 gene in BLBC. JQ-1, a BRD4-bromodomain inhibitor, inhibits the expression and activity of KLF5 in the HCC1806 and HCC1937 cell lines in time- and dose-dependent manners. A new BRD4 inhibitor, compound 870, is more potent than JQ-1 in terms of its ability to inhibit KLF5 and BLBC growth by inducing G1 phase cell cycle arrest. Additionally, a CDK7 inhibitor, THZ1, also inhibits KLF5 and BLBC growth. Our findings suggested that SE regulates KLF5 and that SE inhibitors could be an effective therapeutic strategy for treating BLBC.