Genome-wide transcriptomic analysis of MRTF-active subpopulations in naïve human basal cell carcinoma
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ABSTRACT: Tumor heterogeneity and lack of knowledge about resistant cell states remain a significant barrier to effective targeted cancer therapies. Basal cell carcinomas (BCCs) uniformly depend on Hedgehog (Hh)/Gli signaling for cell growth. We previously identified a nuclear myocardin-related transcription factor (nMRTF) resistance pathway that amplifies Gli1 activity, but nMRTF cell state and key factors driving its accumulation remain unknown. Here, we use three surface markers (LYPD3, TACSTD2, and LY6D) to isolate the nMRTF subpopulation and analyze transcriptomic profiles.
Project description:Tumor heterogeneity and lack of knowledge about resistant cell states remain a significant barrier to effective targeted cancer therapies. Basal cell carcinomas (BCCs) uniformly depend on Hedgehog (Hh)/Gli signaling for cell growth. We previously identified a nuclear myocardin-related transcription factor (nMRTF) resistance pathway that amplifies Gli1 activity, but nMRTF cell state and key factors driving its accumulation remain unknown. Here, we use three surface markers (LYPD3, TACSTD2, and LY6D) to isolate the nMRTF subpopulation and analyze chromatin accessibility profiles.
Project description:Tumor heterogeneity and lack of knowledge about resistant cell states remain a significant barrier to effective targeted cancer therapies. Basal cell carcinomas (BCCs) uniformly depend on Hedgehog (Hh)/Gli signaling for cell growth. We previously identified a nuclear myocardin-related transcription factor (nMRTF) resistance pathway that amplifies Gli1 activity, but nMRTF cell state and key factors driving its accumulation remain unknown. We have determined that AP-1 transcription factor activity is essential to maintain MRTF activation. Here, we treat a murine BCC cell line with small molecule AP-1 inhibitor and analyze chromatin accessibility profiles.
Project description:Tumor heterogeneity and lack of knowledge about resistant cell states remain a significant barrier to effective targeted cancer therapies. Basal cell carcinomas (BCCs) uniformly depend on Hedgehog (Hh)/Gli signaling for cell growth. We previously identified a nuclear myocardin-related transcription factor (nMRTF) resistance pathway that amplifies Gli1 activity, but nMRTF cell state and key factors driving its accumulation remain unknown. Epigenetic analysis of isolated nMRTF human tumor subpopulations demonstrates that cooperative AP-1 and TGFß signaling drive nMRTF activation. In this study, we find that AP-1 signaling drives changes in chromatin accessibility leading to differential Smad3 DNA binding and a transcriptional program of upstream activators of Rho, including RhoGEFs, that facilitate nMRTF activity.
Project description:Tumor heterogeneity and lack of knowledge about resistant cell states remain a significant barrier to effective targeted cancer therapies. Basal cell carcinomas (BCCs) uniformly depend on Hedgehog (Hh)/Gli signaling for cell growth. We previously identified a nuclear myocardin-related transcription factor (nMRTF) resistance pathway that amplifies Gli1 activity, but nMRTF cell state and key factors driving its accumulation remain unknown. We have determined that AP-1 and TGFb transcription factor activity is essential to maintain MRTF activation. Here, we treat a murine BCC cell line with small molecule AP-1 and ALK5 inhibitors and analyze transcriptomic profiles.
Project description:High levels of GLI (GLI1 and GLI2) mRNA and GLI luciferase reporter activity were detected in the androgen independent prostate cancer cell lines DU145 and PC-3 compared to the androgen-dependent LNCaP prostate cancer cell line. Subsequently, we observed that ectopic GLI1 promoted hormone independence in LNCaP cells (LNCaP-GLI1). We compared the gene expression profile of LNCaP-pBP (empty vector), LNCaP-GLI1, DU145, and PC-3 cells globally as well as to identify GLI1-regulated genes that may contribute to hormone independence. RNA was harvested and analysed from LNCap-pBP (control/reference sample), LNCaP-GLI1, DU145 and PC-3 cells
Project description:In the vertebrate neural tube, regional Sonic hedgehog (Shh) signaling invokes a time- and concentration-dependent induction of six different cell populations mediated through Gli transcriptional regulators. Elsewhere in the embryo, Shh/Gli responses invoke different tissue appropriate regulatory programs. To elucidate Shh/Gli regulation of neural fate sepcification, we performed Gli1 ChIP-Seq analysis. We further analyzed two transcription factors whose motifs were enriched in Gli1 ChIP data (Sox2 and Foxa2). Two active histone marks (H3K4me2 and H3K27ac) were additionally analyzed to study activity status of Shh-responsive cis-elements. Active enhancer histone marks and transcription factor binding patterns were obtained from neuralized emrbyoid bodies. Biological replicates were performed for Gli1 and mock FLAG chips. Histone profiling for enhancer marks were taken from time course experiment performed in parallel.
Project description:Despite significant progress in therapy, melanoma is still the most lethal form of skin cancer, with a rising incidence worldwide. Little is known about the impact of deregulated Hedgehog-GLI (HH-GLI) signalling pathway in the progression of this disease. Based on previous research, we hypothesized that in melanoma activation of HH-GLI signaling pathway is non- canonical due to its crosstalk with MAPK signaling pathway, which is the most deregulated pathway in melanoma. In order to investigate the link between the two pathways and to find novel GLI transcriptional targets that could be considered for potential combination therapy, we performed RNA sequencing on three melanoma cell lines with overexpressed GLI1, GLI2 and GLI3 and combined them with results of ChIP sequencing on endogenous GLI1, GLI2 and GLI3 proteins on the same cell lines. RNA-seq revealed a total of 808 DEGs for GLI1, 941 DEGs for GLI2 and 58 DEGs for GLI3. ChIP-seq identified 527 genes that contained GLI1 binding sites in their promoters, 1103 for GLI2 and 553 for GLI3. After combining these results, 21 targets were selected for validation by qPCR. Fifteen of these targets were validated in the tested cell lines, 6 of which were detected by both RNA-seq and ChIP-seq.
Project description:High levels of GLI (GLI1 and GLI2) mRNA and GLI luciferase reporter activity were detected in the androgen independent prostate cancer cell lines DU145 and PC-3 compared to the androgen-dependent LNCaP prostate cancer cell line. Subsequently, we observed that ectopic GLI1 promoted hormone independence in LNCaP cells (LNCaP-GLI1). We compared the gene expression profile of LNCaP-pBP (empty vector), LNCaP-GLI1, DU145, and PC-3 cells globally as well as to identify GLI1-regulated genes that may contribute to hormone independence.
Project description:We describe a relationship between CD24 and the Hedgehog (Hh) ligand Sonic Hedgehog (SHH), and reveal a role for this relationship in the induction of a malignant phenotype in breast cancer. Anchorage-dependent proliferation, anchorage-independent proliferation, invasiveness, and tumorigenicity in breast cancer cells (BCCs) transfected with siRNA and plasmid targeting Hh signaling, CD24, and STAT1 were investigated. CD24 siRNA-transfected BCCs demonstrated higher expression of SHH and GLI1, increased anchorage-independent proliferation, enhanced invasiveness and superior tumorigenicity compared with control. Conversely, CD24 forced-expressing BCCs possessed decreased SHH and GLI1 expression, anchorage-independent proliferation, and invasiveness. Suppression of SHH decreased invasiveness through inhibition of matrix metalloproteinase (MMP)-2 expression, GLI1 expression, anchorage-independent proliferation, tumorigenicity, and tumor volume in vivo in CD24 siRNA-transfected BCCs. DNA microarray analysis identified STAT1 as a connection between CD24 and SHH. CD24 siRNA-transfected BCCs with concurrent STAT1 inhibition exhibited decreased SHH expression, invasiveness, anchorage-independent proliferation, tumorigenicity, and tumor volume in vivo. Consistently, STAT1 over-expression induced elevated SHH expression, invasiveness, and anchorage-independent proliferation in BCCs. These results suggest that CD24 suppresses development of a malignant phenotype by down-regulating SHH transcription through STAT1 inhibition.
Project description:We describe a relationship between CD24 and the Hedgehog (Hh) ligand Sonic Hedgehog (SHH), and reveal a role for this relationship in the induction of a malignant phenotype in breast cancer. Anchorage-dependent proliferation, anchorage-independent proliferation, invasiveness, and tumorigenicity in breast cancer cells (BCCs) transfected with siRNA and plasmid targeting Hh signaling, CD24, and STAT1 were investigated. CD24 siRNA-transfected BCCs demonstrated higher expression of SHH and GLI1, increased anchorage-independent proliferation, enhanced invasiveness and superior tumorigenicity compared with control. Conversely, CD24 forced-expressing BCCs possessed decreased SHH and GLI1 expression, anchorage-independent proliferation, and invasiveness. Suppression of SHH decreased invasiveness through inhibition of matrix metalloproteinase (MMP)-2 expression, GLI1 expression, anchorage-independent proliferation, tumorigenicity, and tumor volume in vivo in CD24 siRNA-transfected BCCs. DNA microarray analysis identified STAT1 as a connection between CD24 and SHH. CD24 siRNA-transfected BCCs with concurrent STAT1 inhibition exhibited decreased SHH expression, invasiveness, anchorage-independent proliferation, tumorigenicity, and tumor volume in vivo. Consistently, STAT1 over-expression induced elevated SHH expression, invasiveness, and anchorage-independent proliferation in BCCs. These results suggest that CD24 suppresses development of a malignant phenotype by down-regulating SHH transcription through STAT1 inhibition.