Project description:The p53 transcription factor is a critical barrier to pancreatic cancer progression. To unravel mechanisms of p53-mediated tumor suppression, we analyzed pancreatic cancer predisposition in mice expressing p53 transactivation domain (TAD) mutants. Surprisingly, we observed that p53 TAD2 mutant behaves as a “super-tumor suppressor”, with an enhanced capacity to suppress pancreatic cancer and to activate a subset of novel p53 target genes. One such gene, Ptpn14, is a direct p53-inducible gene encoding a negative regulator of the Yap oncoprotein. To determine the effects of p53 deficiency on Yap target gene expression in pre-malignant mouse pancreatic intraepithelial neoplasia (PanIN) lesions, we sorted the CD133-positive ductal epithelial cells that make up the PanINs and used these cells for RNA-sequencing analysis. This analysis revealed that a Yap signature is induced upon p53 deficiency, suggesting that p53 loss promotes the induction of a Yap transcriptional program.
Project description:The occurrence of TP53 mutations in late-stage PanINs has led to the idea that p53 acts to suppress malignant transformation of PanINs to PDAC. However, the cellular basis for p53 action during PDAC development has not been explored in detail. Here, we leverage a hyperactive p53 variant – p5353,54 – which we previously showed is a more robust PDAC suppressor than wild-type p53, to elucidate how p53 acts at the cellular level to dampen PDAC development. We find that p5353,54 both limits ADM accumulation and suppresses PanIN cell proliferation and does so more effectively than wild-type p53. We find further that p53 enhances chromatin accessibility at sites controlled by acinar cell identity transcription factors. These findings reveal that p53 acts at multiple stages to suppress PDAC, both by limiting metaplastic transformation of acini and by dampening KRAS signaling in PanINs, thus providing key new understanding of p53 function in PDAC.
Project description:The tumor suppressor p53 is mutated in the majority of human cancers, including pancreatic ductal adenocarcinoma (PDAC)1,2. Wild-type p53 accumulates in response to cellular stress and acts to regulate the expression of genes that influence cell fate and constrain tumorigenesis2. p53 also can modulate cellular metabolism3, though it remains unclear how the metabolic effects of p53 influence tumor suppression or whether the metabolic consequences of p53 loss play a role in disease maintenance. Here, we show that restoring endogenous p53 function in cancer cells derived from a mouse model of PDAC driven by oncogenic Kras and a regulatable p53 short hairpin RNA (shRNA) rewires glucose and glutamine metabolism to support the accumulation of the metabolite alpha-ketoglutarate, an obligate substrate for several enzymes that regulate chromatin methylation. p53 restoration induces transcriptional programs characteristic of pre-neoplastic differentiation, an effect that can be partially recapitulated by addition of cell permeable alpha-ketoglutarate. Consequently, enforcing alpha-ketoglutarate accumulation in p53 deficient cells by inhibiting expression of oxoglutarate dehydrogenase (Ogdh), the enzyme that consumes alpha-ketoglutarate in the tricarboxylic acid cycle, reduces tumor-initiating capacity and promotes tumor differentiation in vivo. In both mouse and human pancreatic cancer, decreasing levels of the alpha-ketoglutarate-dependent chromatin modification 5-hydroxymethylcytosine (5hmC) marks progression from prenoplastic to de-differentiated malignant lesions. p53 restoration or Ogdh suppression promotes accumulation of 5hmC specifically in differentiated tumor cells in vivo. Together, these results nominate alpha-ketoglutarate as an effector of p53-mediated tumor suppression that promotes pre-neoplastic differentiation and suppresses malignant progression.
Project description:Lung cancer is the leading cause of cancer deaths worldwide. TP53 tumor suppressor gene mutations occur in 50% of lung adenocarcinomas (LUADs) and are linked to poor prognosis, but how p53 suppresses LUAD development remains enigmatic. We show here that p53 suppresses LUAD by governing cell state, by promoting alveolar type 1 (AT1) differentiation. Using mice expressing oncogenic Kras and null, wild-type, or hypermorphic p53 alleles in alveolar type 2 (AT2) cells, we observed graded effects of p53 on LUAD initiation and progression. RNA-sequencing and ATAC-sequencing of LUAD cells uncovered a p53-induced AT1 differentiation program during tumor suppression in vivo through direct DNA binding, chromatin remodeling, and AT1 gene induction. Single-cell transcriptomics analyses revealed that during LUAD evolution, p53 promotes AT1 differentiation through action in a transitional cell state analogous to a transient intermediary seen during AT2-to-AT1 differentiation in alveolar injury repair. Notably, p53 inactivation resulted in the inappropriate persistence of these transitional cancer cells accompanied by upregulated growth signaling and divergence from lung lineage identity, characteristics associated with LUAD progression. Analysis of p53wt and p53-null mice showed that p53 also directs alveolar regeneration after injury, by regulating AT2 self-renewal and promoting transitional cell differentiation into AT1 cells. Collectively, these findings illuminate mechanisms of p53-mediated LUAD suppression, in which p53 governs alveolar differentiation, and suggest that tumor suppression reflects a fundamental role of p53 in orchestrating tissue repair after injury.
Project description:Lung cancer is the leading cause of cancer deaths worldwide. TP53 tumor suppressor gene mutations occur in 50% of lung adenocarcinomas (LUADs) and are linked to poor prognosis, but how p53 suppresses LUAD development remains enigmatic. We show here that p53 suppresses LUAD by governing cell state, by promoting alveolar type 1 (AT1) differentiation. Using mice expressing oncogenic Kras and null, wild-type, or hypermorphic p53 alleles in alveolar type 2 (AT2) cells, we observed graded effects of p53 on LUAD initiation and progression. RNA-sequencing and ATAC-sequencing of LUAD cells uncovered a p53-induced AT1 differentiation program during tumor suppression in vivo through direct DNA binding, chromatin remodeling, and AT1 gene induction. Single-cell transcriptomics analyses revealed that during LUAD evolution, p53 promotes AT1 differentiation through action in a transitional cell state analogous to a transient intermediary seen during AT2-to-AT1 differentiation in alveolar injury repair. Notably, p53 inactivation resulted in the inappropriate persistence of these transitional cancer cells accompanied by upregulated growth signaling and divergence from lung lineage identity, characteristics associated with LUAD progression. Analysis of p53wt and p53-null mice showed that p53 also directs alveolar regeneration after injury, by regulating AT2 self-renewal and promoting transitional cell differentiation into AT1 cells. Collectively, these findings illuminate mechanisms of p53-mediated LUAD suppression, in which p53 governs alveolar differentiation, and suggest that tumor suppression reflects a fundamental role of p53 in orchestrating tissue repair after injury.
Project description:Lung cancer is the leading cause of cancer deaths worldwide. TP53 tumor suppressor gene mutations occur in 50% of lung adenocarcinomas (LUADs) and are linked to poor prognosis, but how p53 suppresses LUAD development remains enigmatic. We show here that p53 suppresses LUAD by governing cell state, by promoting alveolar type 1 (AT1) differentiation. Using mice expressing oncogenic Kras and null, wild-type, or hypermorphic p53 alleles in alveolar type 2 (AT2) cells, we observed graded effects of p53 on LUAD initiation and progression. RNA-sequencing and ATAC-sequencing of LUAD cells uncovered a p53-induced AT1 differentiation program during tumor suppression in vivo through direct DNA binding, chromatin remodeling, and AT1 gene induction. Single-cell transcriptomics analyses revealed that during LUAD evolution, p53 promotes AT1 differentiation through action in a transitional cell state analogous to a transient intermediary seen during AT2-to-AT1 differentiation in alveolar injury repair. Notably, p53 inactivation resulted in the inappropriate persistence of these transitional cancer cells accompanied by upregulated growth signaling and divergence from lung lineage identity, characteristics associated with LUAD progression. Analysis of p53wt and p53-null mice showed that p53 also directs alveolar regeneration after injury, by regulating AT2 self-renewal and promoting transitional cell differentiation into AT1 cells. Collectively, these findings illuminate mechanisms of p53-mediated LUAD suppression, in which p53 governs alveolar differentiation, and suggest that tumor suppression reflects a fundamental role of p53 in orchestrating tissue repair after injury.
Project description:Lung cancer is the leading cause of cancer deaths worldwide. TP53 tumor suppressor gene mutations occur in 50% of lung adenocarcinomas (LUADs) and are linked to poor prognosis, but how p53 suppresses LUAD development remains enigmatic. We show here that p53 suppresses LUAD by governing cell state, by promoting alveolar type 1 (AT1) differentiation. Using mice expressing oncogenic Kras and null, wild-type, or hypermorphic p53 alleles in alveolar type 2 (AT2) cells, we observed graded effects of p53 on LUAD initiation and progression. RNA-sequencing and ATAC-sequencing of LUAD cells uncovered a p53-induced AT1 differentiation program during tumor suppression in vivo through direct DNA binding, chromatin remodeling, and AT1 gene induction. Single-cell transcriptomics analyses revealed that during LUAD evolution, p53 promotes AT1 differentiation through action in a transitional cell state analogous to a transient intermediary seen during AT2-to-AT1 differentiation in alveolar injury repair. Notably, p53 inactivation resulted in the inappropriate persistence of these transitional cancer cells accompanied by upregulated growth signaling and divergence from lung lineage identity, characteristics associated with LUAD progression. Analysis of p53wt and p53-null mice showed that p53 also directs alveolar regeneration after injury, by regulating AT2 self-renewal and promoting transitional cell differentiation into AT1 cells. Collectively, these findings illuminate mechanisms of p53-mediated LUAD suppression, in which p53 governs alveolar differentiation, and suggest that tumor suppression reflects a fundamental role of p53 in orchestrating tissue repair after injury.
Project description:Lung cancer is the leading cause of cancer deaths worldwide. TP53 tumor suppressor gene mutations occur in 50% of lung adenocarcinomas (LUADs) and are linked to poor prognosis, but how p53 suppresses LUAD development remains enigmatic. We show here that p53 suppresses LUAD by governing cell state, by promoting alveolar type 1 (AT1) differentiation. Using mice expressing oncogenic Kras and null, wild-type, or hypermorphic p53 alleles in alveolar type 2 (AT2) cells, we observed graded effects of p53 on LUAD initiation and progression. RNA-sequencing and ATAC-sequencing of LUAD cells uncovered a p53-induced AT1 differentiation program during tumor suppression in vivo through direct DNA binding, chromatin remodeling, and AT1 gene induction. Single-cell transcriptomics analyses revealed that during LUAD evolution, p53 promotes AT1 differentiation through action in a transitional cell state analogous to a transient intermediary seen during AT2-to-AT1 differentiation in alveolar injury repair. Notably, p53 inactivation resulted in the inappropriate persistence of these transitional cancer cells accompanied by upregulated growth signaling and divergence from lung lineage identity, characteristics associated with LUAD progression. Analysis of p53wt and p53-null mice showed that p53 also directs alveolar regeneration after injury, by regulating AT2 self-renewal and promoting transitional cell differentiation into AT1 cells. Collectively, these findings illuminate mechanisms of p53-mediated LUAD suppression, in which p53 governs alveolar differentiation, and suggest that tumor suppression reflects a fundamental role of p53 in orchestrating tissue repair after injury.
Project description:Lung cancer is the leading cause of cancer deaths worldwide. TP53 tumor suppressor gene mutations occur in 50% of lung adenocarcinomas (LUADs) and are linked to poor prognosis, but how p53 suppresses LUAD development remains enigmatic. We show here that p53 suppresses LUAD by governing cell state, by promoting alveolar type 1 (AT1) differentiation. Using mice expressing oncogenic Kras and null, wild-type, or hypermorphic p53 alleles in alveolar type 2 (AT2) cells, we observed graded effects of p53 on LUAD initiation and progression. RNA-sequencing and ATAC-sequencing of LUAD cells uncovered a p53-induced AT1 differentiation program during tumor suppression in vivo through direct DNA binding, chromatin remodeling, and AT1 gene induction. Single-cell transcriptomics analyses revealed that during LUAD evolution, p53 promotes AT1 differentiation through action in a transitional cell state analogous to a transient intermediary seen during AT2-to-AT1 differentiation in alveolar injury repair. Notably, p53 inactivation resulted in the inappropriate persistence of these transitional cancer cells accompanied by upregulated growth signaling and divergence from lung lineage identity, characteristics associated with LUAD progression. Analysis of p53wt and p53-null mice showed that p53 also directs alveolar regeneration after injury, by regulating AT2 self-renewal and promoting transitional cell differentiation into AT1 cells. Collectively, these findings illuminate mechanisms of p53-mediated LUAD suppression, in which p53 governs alveolar differentiation, and suggest that tumor suppression reflects a fundamental role of p53 in orchestrating tissue repair after injury.