Project description:Esophageal cancer is one of the most common cancers where TP53 is mutated frequently. Esophageal squamous cell carcinoma (ESCC) is the major subtype of esophageal cancer, and is one of the most lethal cancers worldwide. ESCC evolves often to lung metastasis, which is associated with a dismal prognosis. P53R175H (homologous to Trp53R172H in mice) is a common hot spot mutation. How metastasis is regulated by p53R175H in ESCC, or cancers in general, remains to be elucidated. To investigate p53R175H mediated molecular mechanisms, we utilized germline Trp53R172H/- mice, and generated esophageal specific Trp53-/- mice and Trp53+/+ mice treated with the 4-NQO esophageal-specific carcinogen (a common exposure in humans) to model ESCC. In the primary Trp53R172H/- tumor cell lines established from these mouse models, we depleted Trp53R172H (shTrp53) and observed a marked reduction in cell invasion in vitro and lung metastasis burden in a tail-vein injection model in comparing isogenic cells (shCtrl). Furthermore, to understand the molecular basis for mutant p53 driven lung metastasis, we performed bulk RNA-seq to compare gene expression profiles of metastatic and primary shCtrl and shTrp53 cells. We performed Gene Set Enrichment Analysis (GSEA) and identified the YAP-BIRC5 axis as a potential mediator of Trp53R172H mediated metastasis. As a target gene of YAP, BIRC5 encodes an anti-apoptotic protein, namely survivin. We demonstrate that survivin expression increases in the presence of Trp53R172H but not wild-type Trp53. Furthermore, depletion of survivin decreases Trp53R172H driven lung metastasis. Mechanistically, Trp53R172H but not wild-type Trp53, binds with YAP in ESCC cells, suggesting their cooperation to induce survivin expression. Furthermore, survivin high expression level is associated with increased metastasis in several GI cancer, suggesting that survivin may be a key regulator to metastasis. Taken together, this study unravels new insights into how mutant p53 mediates metastasis.
Project description:The TP53 transcription factor is frequently mutated at later stages of epithelial cancers, indicating a possible role in their invasion and metastasis. Importantly, in most cases rather than a simple loss of function p53 mutation, point mutations of p53 accumulate at the protein level and may have dominant negative functions. This study analyses gene expression differences between mice harbouring p53 mutation who do and do not develop metastasis. Samples were collected from Genetically modified mice of the genotypes indicated in the characteristics. The presence or absence of metastasis was scored and gene expression differences between the two groups measured.
Project description:The TP53 transcription factor is frequently mutated at later stages of epithelial cancers, indicating a possible role in their invasion and metastasis. Importantly, in most cases rather than a simple loss of function p53 mutation, point mutations of p53 accumulate at the protein level and may have dominant negative functions. This study analyses gene expression differences between mice harbouring p53 mutation who do and do not develop metastasis.
Project description:Mutant forms of p53 protein often possess pro-tumorigenic function, conferring increased survival and migration to tumor cells via its “gain of function” activity. Whether and how a common polymorphism in TP53 at amino acid 72 (Pro72Arg, hereafter P72 and R72) impacts this gain of function has not been determined. We show that mutant p53 enhances migration and metastasis of tumors through the ability to bind and regulate PGC-1α, and that this regulation is markedly impacted by the codon 72 polymorphism. Tumor cells with the R72 variant of mutant p53 show increased PGC-1α function, along with greatly increased mitochondrial function and metastatic capability. Breast cancers containing mutant p53 and the R72 variant show poorer prognosis compared to P72. The combined results reveal PGC-1α as a novel “gain of function” partner of mutant p53, and indicate that the codon 72 polymorphism influences the impact of mutant p53 on metabolism and metastasis.
Project description:The liver possesses remarkable regenerative capacity in response to injury. Upon partial hepatectomy (PHx), terminally differentiated hepatocytes in the remaining liver enter the cell cycle and restore the liver mass and function within weeks. However, liver regeneration is often impaired in livers with chronic diseases. Survivin, an inhibitor of apoptosis protein (IAP) and member of chromosome passenger complex (CPC), plays versatile roles in cell mitosis and apoptosis. We and others found that the expression of Survivin was highly increased in liver during PHx-induced liver regeneration, which indicated that Survivin played important roles in this process. However, the function of Survivin in liver regeneration remains largely undefined. Here, using mice with genetic deletion of Survivin, we found that during PHx-induced liver regeneration Survivin regulated both hepatocyte G1/S phase transition by inhibiting the expression of p21 and G2/M phase transition by regulating the localization of CPC. Moreover, restoration of Survivin expression in Survivin-deficient hepatocytes inhibited p21 expression and promote both hepatocyte G1/S and G2/M transition during PHx-induced liver regeneration.
Project description:TGFβ ligands act as tumor suppressors in early stage tumors but are paradoxically diverted into potent prometastatic factors in advanced cancers. The molecular nature of this switch remains enigmatic. We now show that TGFβ-dependent cell migration, invasion and metastasis are empowered by mutant-p53. To investigate the specific gene expression program by which mutant-p53 and TGFβ control invasion and metastasis in breast cancer cells, we compared the TGFβ transcriptomic profile of control and mutant-p53 depleted MDA-MB-231 cells. Keywords: expression profiling by array