RESUMEN
Loss of p53 function contributes to the development of many cancers. While cell-autonomous consequences of p53 mutation have been studied extensively, the role of p53 in regulating the anti-tumor immune response is still poorly understood. Here, we show that loss of p53 in cancer cells modulates the tumor-immune landscape to circumvent immune destruction. Deletion of p53 promotes the recruitment and instruction of suppressive myeloid CD11b+ cells, in part through increased expression of CXCR3/CCR2-associated chemokines and macrophage colony-stimulating factor (M-CSF), and attenuates the CD4+ T helper 1 (Th1) and CD8+ T cell responses in vivo. p53-null tumors also show an accumulation of suppressive regulatory T (Treg) cells. Finally, we show that two key drivers of tumorigenesis, activation of KRAS and deletion of p53, cooperate to promote immune tolerance.
Asunto(s)
Células Mieloides/metabolismo , Linfocitos T Reguladores/metabolismo , Proteína p53 Supresora de Tumor/metabolismo , Animales , Humanos , RatonesRESUMEN
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RESUMEN
Transplantable murine models of ovarian high grade serous carcinoma (HGSC) remain an important research tool. We previously showed that ID8, a widely-used syngeneic model of ovarian cancer, lacked any of the frequent mutations in HGSC, and used CRISPR/Cas9 gene editing to generate derivatives with deletions in Trp53 and Brca2. Here we have used one ID8 Trp53 -/- clone to generate further mutants, with additional mutations in Brca1, Pten and Nf1, all of which are frequently mutated or deleted in HGSC. We have also generated clones with triple deletions in Trp53, Brca2 and Pten. We show that ID8 Trp53 -/-;Brca1 -/- and Trp53 -/-;Brca2 -/- cells have defective homologous recombination and increased sensitivity to both platinum and PARP inhibitor chemotherapy compared to Trp53 -/-. By contrast, loss of Pten or Nf1 increases growth rate in vivo, and reduces survival following cisplatin chemotherapy in vivo. Finally, we have also targeted Trp53 in cells isolated from a previous transgenic murine fallopian tube carcinoma model, and confirmed that loss of p53 expression in this second model accelerates intraperitoneal growth. Together, these CRISPR-generated models represent a new and simple tool to investigate the biology of HGSC, and the ID8 cell lines are freely available to researchers.
Asunto(s)
Sistemas CRISPR-Cas/genética , Cistadenocarcinoma Seroso/tratamiento farmacológico , Neurofibromina 1/genética , Neoplasias Ováricas/tratamiento farmacológico , Fosfohidrolasa PTEN/genética , Platino (Metal)/uso terapéutico , Proteínas Supresoras de Tumor/genética , Animales , Proteína BRCA1 , Proteína BRCA2/deficiencia , Proteína BRCA2/genética , Línea Celular Tumoral , Supervivencia Celular , Cistadenocarcinoma Seroso/genética , Cistadenocarcinoma Seroso/mortalidad , Cistadenocarcinoma Seroso/patología , Modelos Animales de Enfermedad , Femenino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Clasificación del Tumor , Neoplasias Ováricas/genética , Neoplasias Ováricas/mortalidad , Neoplasias Ováricas/patología , Fosfohidrolasa PTEN/deficiencia , Platino (Metal)/química , Platino (Metal)/farmacología , Inhibidores de Poli(ADP-Ribosa) Polimerasas/uso terapéutico , Tasa de Supervivencia , Proteína p53 Supresora de Tumor/deficiencia , Proteína p53 Supresora de Tumor/genética , Proteínas Supresoras de Tumor/deficienciaRESUMEN
Oncolytic adenoviral mutants infect human malignant cells and replicate selectively within them. This induces direct cytotoxicity that can also trigger profound innate and adaptive immune responses. However, the mechanism by which adenoviruses produce cell death remains uncertain. We previously suggested that type 5 adenoviruses, including the E1A CR2 deletion mutant dl922-947, might induce a novel form of programmed death resembling necroptosis. Here we have investigated the roles of core necrosis proteins RIPK1, RIPK3 and MLKL in the cytotoxicity of dl922-947 and other adenovirus serotypes. By electron microscopy, we show that dl922-947 induces similar necrotic morphology as TSZ treatment (TNF-α, Smac mimetic, zVAD.fmk). However, dl922-947-mediated death is independent of TNF-α signalling, does not require RIPK1 and does not rely upon the presence of MLKL. However, inhibition of caspases, specifically caspase-8, induces necroptosis that is RIPK3 dependent and significantly enhances dl922-947 cytotoxicity. Moreover, using CRISPR/Cas9 gene editing, we demonstrate that the increase in cytotoxicity seen upon caspase inhibition is also MLKL dependent. Even in the absence of caspase inhibition, RIPK3 expression promotes dl922-947 and wild-type adenovirus type 5 efficacy both in vitro and in vivo. Together, these results suggest that adenovirus induces a form of programmed necrosis that differs from classical TSZ necroptosis.
