Project description:Acinar cells have been proposed as a cell-of-origin for pancreatic intraepithelial neoplasia (PanIN) after undergoing a highly regulated acinar to ductal metaplasia (ADM) process. ADM can be triggered by pancreatitis causing acinar cells de-differentiate to a ductal-like state. We identify Fra1 (gene name Fosl1) as the most enriched transcription factor during KrasG12D acute pancreatitis mediated injury. We have elucidated the functional role of Fra1 by generating an acinar-specific Fosl1 knockout mouse expressing KrasG12D (Ptf1aCreERT;KrasG12D;Fosl1fl/fl;YFP) . Using single nuclei ATAC-seq and bulk-RNA seq, we used pseudotime analysis and developed a gene-regulatory network governing de-differentiation to demonstrate that Fosl1 knockout mice are delayed in the onset of ADM and accompanying recovery. Fosl1 depletion prevents the pro-inflammatory effects of G-CSF, an ADM-promoting cytokine, suggesting that the G-CSF/Fra1 signaling axis can modulate ADM. Overall, our studies mark the first time a discrete transcriptional factor has been linked to the temporal regulation of ADM.
Project description:PARP7 inhibitors reduce tumor growth in a cell-autonomous manner and by enhancing immune recognition through restoring nucleic acid (NA)-sensing-dependent innate immune signaling. However, the molecular targets of PARP7-mediated ADP-ribosylation, regulating cell survival and innate immune signaling, remained elusive. Here, we identified PARP7 as a nuclear and cysteine-specific mono-ART that ADP-ribosylates proteins critical for regulating gene expression, such as the AP-1 transcription factor FRA1. Upon PARP7 inhibition the loss of FRA1 ADP-ribosylation increased FRA1 degradation in a PSMC3 and proteasomal-dependent manner. To further investigate how FRA1 promotes cell survival, we investigated transcriptional changes after RBN-2397 treatment and FRA1 knockdown in the PARP7 inhibitor sensitive cell line NCI-H1975 by RNA sequencing.
Project description:Acinar cells have been proposed as a cell-of-origin for pancreatic intraepithelial neoplasia (PanIN) after undergoing a highly regulated acinar to ductal metaplasia (ADM) process. ADM can be triggered by pancreatitis causing acinar cells de-differentiate to a ductal-like state. We identify Fra1 (gene name Fosl1) as the most enriched transcription factor during KrasG12D acute pancreatitis mediated injury. We have elucidated the functional role of Fra1 by generating an acinar-specific Fosl1 knockout mouse expressing KrasG12D (Ptf1aCreERT;KrasG12D;Fosl1fl/fl;YFP) . Using single nuclei ATAC-seq and bulk-RNA seq, we used pseudotime analysis and developed a gene-regulatory network governing de-differentiation to demonstrate that Fosl1 knockout mice are delayed in the onset of ADM and accompanying recovery. Fosl1 depletion prevents the pro-inflammatory effects of G-CSF, an ADM-promoting cytokine, suggesting that the G-CSF/Fra1 signaling axis can modulate ADM. Overall, our studies mark the first time a discrete transcriptional factor has been linked to the temporal regulation of ADM.
Project description:Acinar cells have been proposed as a cell-of-origin for pancreatic intraepithelial neoplasia (PanIN) after undergoing a highly regulated acinar to ductal metaplasia (ADM) process. ADM can be triggered by pancreatitis causing acinar cells de-differentiate to a ductal-like state. We identify Fra1 (gene name Fosl1) as the most enriched transcription factor during KrasG12D acute pancreatitis mediated injury. We have elucidated the functional role of Fra1 by generating an acinar-specific Fosl1 knockout mouse expressing KrasG12D (Ptf1aCreERT;KrasG12D;Fosl1fl/fl;YFP) . Using single nuclei ATAC-seq and bulk-RNA seq, we used pseudotime analysis and developed a gene-regulatory network governing de-differentiation to demonstrate that Fosl1 knockout mice are delayed in the onset of ADM and accompanying recovery. Fosl1 depletion prevents the pro-inflammatory effects of G-CSF, an ADM-promoting cytokine, suggesting that the G-CSF/Fra1 signaling axis can modulate ADM. Overall, our studies mark the first time a discrete transcriptional factor has been linked to the temporal regulation of ADM.
Project description:PARP7 inhibitors suppress tumor growth in a cell autonomous manner and by activating the immune system through restoring immune signaling. Nevertheless, the targets of PARP7-mediated ADP-ribosylation that regulate innate immune signaling and cancer cell survival remain elusive. Here, we identified PARP7 as a nuclear and cysteine-specific mono-ADP-ribosyltransferase that modified proteins critical for regulating transcription, such as the AP-1 transcription factor FRA1. Loss of FRA1 ADP-ribosylation via PARP7 inhibition by RBN-2397 or mutation of the ADP-ribosylation site C97 increased FRA1 degradation by PSMC3 and the proteasome. We found that the reduction in FRA1 protein levels promoted IRF3 and IRF1-dependent innate immune signaling and CASP8-mediated apoptosis. Furthermore, we demonstrated that high PARP7 expression are critical for inducing apoptosis in FRA1-positive cancer cells using the PARP7 inhibitor. Collectively, our findings highlight the connected roles of PARP7 and FRA1 and emphasize the clinical potential of PARP7 inhibitors for FRA1-driven cancers.
Project description:Bladder cancer is mostly present in the form of urothelium carcinoma, causing over 150.000 deaths each year. Its histopathological classification as muscle invasive and non-muscle invasive is the most prominent aspect, affecting the prognosis and progression of this disease. In this study, we defined the active regulatory landscape of MIBC and NMIBC cell lines using H3K27ac-seq and used an integrative data approach to combine our findings with existing data. Our analysis revealed FRA1 and FLI1 as the two critical transcription factors differentially regulating MIBC regulatory landscape. Importantly, we show that FRA1 and FLI1 regulate the genes involved in epithelial cell migration and cell junction organization. Knock-down of FRA1 and FLI1 in MIBC revealed the downregulation of several EMT-related genes such as MAP4K4 and FLOT1. Further, ChIP-SICAP performed for FRA1 and FLI1 enabled us to infer chromatin binding partners of these two transcription factors and link this information with their target genes, providing a comprehensive regulatory circuit for the genes implicated in invasive ability of the bladder cancer cells. Finally, we show that knock-down of FRA1 and FLI1 results in statistically significant less migration of cells using IC-CHIP assays. Our results collectively highlight the role of these two transcription factors in invasive characteristics of bladder cancer in selection and design of targeted options for treatment of MIBC.
Project description:Fra1 expression in LM2 cells (MDA-MB-231 derivatives, clone 4173 obtained from J. Massague) was silenced using two independent lentiviral sh-RNA constructs. Gene expresssion levels were compared to those in control cells transduced with empty vector.