Project description:Loss of Pten in the KrasG12D;Amhr2-Cre mutant mice leads to the transformation of ovarian surface epithelial (OSE) cells and rapid development of low-grade, invasive serous adenocarcinomas. Tumors occur with 100% penetrance and express elevated expression of wild type tumor repressor protein 53 (TRP53). To test the functions of TRP53 in the Pten;Kras (Trp53+) mice, we disrupted the Trp53 gene yielding Pten;Kras(Trp53-) mice. By comparing morphology and gene expression profiles in the Trp53+ and Trp53- OSE cells, we document that wild-type TRP53 acts as a major promoter of OSE cell survival and differentiation: cells lacking Trp53 are transformed yet are less adherent, migratory and invasive and exhibit a gene expression profile more like normal OSE cells. These results provide a new paradigm: wild type TRP53 does not preferentially induce apoptotic or senescent related genes in the Pten;Kras(Trp53+) cancer cells but rather increases genes regulating DNA repair, cell cycle progression and proliferation and decreases putative tumor suppressor genes. However, if TRP53 activity is forced higher by exposure to nutlin-3a (an MDM2 antagonist), TRP53 suppresses DNA repair genes and induces the expression of genes that control cell cycle arrest and apoptosis. Thus, in the Pten;Kras(Trp53+) mutant mouse OSE cells and likely in human TP53+ low grade ovarian cancer cells, wild type TRP53 controls global molecular changes that are dependent on its activation status. These results suggest that activation of TP53 may provide a promising new therapy for managing type I ovarian cancer and other cancers in humans where wild-type TP53 is expressed. A direct comparison of ovarian surface epithelia cells from three different genotype mice
Project description:Loss of Pten in the KrasG12D;Amhr2-Cre mutant mice leads to the transformation of ovarian surface epithelial (OSE) cells and rapid development of low-grade, invasive serous adenocarcinomas. Tumors occur with 100% penetrance and express elevated expression of wild type tumor repressor protein 53 (TRP53). To test the functions of TRP53 in the Pten;Kras (Trp53+) mice, we disrupted the Trp53 gene yielding Pten;Kras(Trp53-) mice. By comparing morphology and gene expression profiles in the Trp53+ and Trp53- OSE cells, we document that wild-type TRP53 acts as a major promoter of OSE cell survival and differentiation: cells lacking Trp53 are transformed yet are less adherent, migratory and invasive and exhibit a gene expression profile more like normal OSE cells. These results provide a new paradigm: wild type TRP53 does not preferentially induce apoptotic or senescent related genes in the Pten;Kras(Trp53+) cancer cells but rather increases genes regulating DNA repair, cell cycle progression and proliferation and decreases putative tumor suppressor genes. However, if TRP53 activity is forced higher by exposure to nutlin-3a (an MDM2 antagonist), TRP53 suppresses DNA repair genes and induces the expression of genes that control cell cycle arrest and apoptosis. Thus, in the Pten;Kras(Trp53+) mutant mouse OSE cells and likely in human TP53+ low grade ovarian cancer cells, wild type TRP53 controls global molecular changes that are dependent on its activation status. These results suggest that activation of TP53 may provide a promising new therapy for managing type I ovarian cancer and other cancers in humans where wild-type TP53 is expressed.
Project description:The functional status of the tumor repressor protein (TP53 or TRP53) is a defining feature of ovarian cancer. Mutant or null alleles of TP53 are expressed in greater than 90% of all high-grade serous adenocarcinomas. Wild type TP53 is elevated in low-grade serous adenocarcinomas in women and in our Pten/Kras/Amhr2-Cre mutant mouse model. Disruption of the Trp53 gene in this mouse model did not lead to high-grade ovarian cancer but did increase expression of estrogen receptor alpha (ERalpha; ESR1) and markedly enhanced the responsiveness of these cells to estrogen. Specifically, when Trp53 positive and Trp53 null mutant mice were treated with estradiol or vehicle, only the Trp53 null and Esr1 positive tumors respond vigorously to estradiol in vivo and exhibit features characteristic of high-grade type ovarian cancer: invasive growth into the ovarian stroma, rampant metastases to the peritoneal cavity and signs of genomic instability. Estrogen promoted and progesterone suppressed the growth of Trp53 null ovarian tumors and tumor cells injected intraperitoneally (IP), subcutaneously (SC) or when grown in matrigel. Exposure of the Trp53 depleted cells to estrogen also has a profound impact on the tumor microenvironment and immune-related events. These results led to the new paradigm that TRP53 status is related to the susceptibility of transformed ovarian surface epithelial (OSE) cells to estradiol-induced metastases and genomic instability. This novel finding is relevant not only for women during their reproductive years but also for women on hormone (estradiol) replacement therapies. A direct comparison of ovarian surface epithelia cells from two different genotype mice
Project description:The functional status of the tumor repressor protein (TP53 or TRP53) is a defining feature of ovarian cancer. Mutant or null alleles of TP53 are expressed in greater than 90% of all high-grade serous adenocarcinomas. Wild type TP53 is elevated in low-grade serous adenocarcinomas in women and in our Pten/Kras/Amhr2-Cre mutant mouse model. Disruption of the Trp53 gene in this mouse model did not lead to high-grade ovarian cancer but did increase expression of estrogen receptor alpha (ERalpha; ESR1) and markedly enhanced the responsiveness of these cells to estrogen. Specifically, when Trp53 positive and Trp53 null mutant mice were treated with estradiol or vehicle, only the Trp53 null and Esr1 positive tumors respond vigorously to estradiol in vivo and exhibit features characteristic of high-grade type ovarian cancer: invasive growth into the ovarian stroma, rampant metastases to the peritoneal cavity and signs of genomic instability. Estrogen promoted and progesterone suppressed the growth of Trp53 null ovarian tumors and tumor cells injected intraperitoneally (IP), subcutaneously (SC) or when grown in matrigel. Exposure of the Trp53 depleted cells to estrogen also has a profound impact on the tumor microenvironment and immune-related events. These results led to the new paradigm that TRP53 status is related to the susceptibility of transformed ovarian surface epithelial (OSE) cells to estradiol-induced metastases and genomic instability. This novel finding is relevant not only for women during their reproductive years but also for women on hormone (estradiol) replacement therapies.
Project description:Background: BRCA mutations in ovarian cancer (OC) are associated with increased tumor-infiltrating lymphocytes and inflammatory features, yet immunotherapy for OC has failed to meet expectations. This study hypothesizes that BRCA1 or BRCA2 deficiency differently influences the response to cancer vaccine. Methods: We used the syngeneic orthotopic ID8 mouse ovarian tumor models deficient for Trp53, Trp53 and Brca1, or Trp53 and Brca2. Tumor-implanted mice were vaccinated with a dendritic cell-based whole tumor lysate vaccine (termed OCDC) alone or in combination with anti-VEGF therapy, PARP inhibitor, and/or anti-PD-1 immune checkpoint inhibitor. Tumor burden, mice survival and monitoring of T cell responses were evaluated by bioluminescence imaging, flow cytometry and interferon gamma (IFNg)-ELISpot assay. Transcriptomic profiling of tumor cell and immune cell-compartments was performed using NanoString GeoMx digital spatial profiling. Results: Brca1 deficiency—but not Brca2— impairs effectiveness of OCDC vaccine. OCDC vaccine reduced tumor growth rates and improved survival of mice implanted with Trp53-/- and Trp53-/-Brca2-/-ID8 tumors, but was ineffective in mice implanted Trp53-/-Brca1-/- tumor model. Transcriptomic analysis revealed that tumors responsive to OCDC (Brca wild-type or Brca2-/-) underwent metabolic and immunologic reprogramming post-vaccination, unlike Brca1-/- tumors. Inefficacy of the cancer vaccine was driven by a tumor microenvironment that was already inflamed, characterized by a high level of activated yet exhausted T cells, which hinder additional immune activation by vaccination. Combining OCDC with anti-VEGF and PARP inhibitors partially overcame vaccine resistance in Brca1-/- tumors, while adding anti-PD-1 further improved vaccine effectiveness by boosting T cell activity and promoting long-term survival. Conclusion: These findings highlight BRCA1’s role in cancer vaccine sensitivity and support using rational combinations to overcome vaccine inefficacy in BRCA1-mutated OC.
Project description:Ovarian cancer is the most lethal gynecological malignancy. Deepening our knowledge of the interactions within the tumor microenvironment (TME) is important for discovering new targeted treatment strategies. Transglutaminase 2 (TG2) is a protein implicated in many biological and pathophysiological processes, including promoting tumor progression in ovarian cancer. Its role in disease progression has been studied in ovarian cancer cells; however, its role in the ovarian TME is less understood. Using the ID8 Trp53-/- Brca1-/- and KPCA.B syngeneic mouse models of ovarian cancer, we defined the contribution of TG2 in the TME to the metastatic process. Lack of TG2 in the TME prolonged survival in the ID8 Trp53-/- Brca1-/- metastatic model. Through extensive analysis of the immune composition in both the primary tumor and metastatic ascites in the ID8 Trp53-/- Brca1-/- model, we discovered that the lack of host TG2 resulted in decreased frequency of immunosuppressive tumor-associated macrophages, and increased frequency of T cells, NK cells, and B cells. RNA sequencing of the primary tumors with or without TG2 present in the TME, revealed an enrichment of pathways related to B cell activation and regulation, highlighting a crucial role for TG2 in modulating B cells to enhance survival in the ID8 Trp53-/- Brca1-/- model. Taken together, our findings highlight the importance of TG2 in the TME for ovarian cancer metastasis, potentially through the activation of humoral immunity.
Project description:To demonstrate the use of a whole-genome oligonucleotide array to perform expression profiling on a series of microdissected late-stage, high-grade papillary serous ovarian adenocarcinomas to establish a prognostic gene signature correlating with survival and to identify novel survival factors in ovarian cancer. Advanced stage papillary serous tumors of the ovary are responsible for the majority of ovarian cancer deaths, yet the molecular determinants modulating patient survival are poorly characterized. We identify and validate a prognostic gene expression signature correlating with survival in a series of microdissected serous ovarian tumors. Experiment Overall Design: We identified 53 advanced stage, high-grade primary tumor specimens and 10 normal ovarian surface epithelium (OSE) brushings.
Project description:Mutation of TP53, a tumor suppressor in cancer, is common and leads to extremely poor prognosis. To identify vulnerabilities in TP53-mutated tumors, we performed genome-wide CRISPR/Cas9 screens using isogenic Trp53 wild-type and knockout mouse acute myeloid leukemia (AML) lines. Here, we show that histone gene regulation governed by the XPO7-NPAT pathway is essential for survival of TP53-mutated AML cells. In TP53 wild-type cells, XPO7 enhances p53 nuclear localization and functions as a tumor suppressor, but in TP53-mutated cells, XPO7 promotes cell proliferation by retaining NPAT, a histone gene activator, in the nucleus. NPAT depletion led to genome-wide histone loss, enhancing vulnerability to genotoxic stress. Human AML cases show predominant expression of XPO7 and NPAT when TP53 is mutated, suggesting a potential therapeutic vulnerability.
Project description:Mutation of TP53, a tumor suppressor in cancer, is common and leads to extremely poor prognosis. To identify vulnerabilities in TP53-mutated tumors, we performed genome-wide CRISPR/Cas9 screens using isogenic Trp53 wild-type and knockout mouse acute myeloid leukemia (AML) lines. Here, we show that histone gene regulation governed by the XPO7-NPAT pathway is essential for survival of TP53-mutated AML cells. In TP53 wild-type cells, XPO7 enhances p53 nuclear localization and functions as a tumor suppressor, but in TP53-mutated cells, XPO7 promotes cell proliferation by retaining NPAT, a histone gene activator, in the nucleus. NPAT depletion led to genome-wide histone loss, enhancing vulnerability to genotoxic stress. Human AML cases show predominant expression of XPO7 and NPAT when TP53 is mutated, suggesting a potential therapeutic vulnerability.