Redox Mechanism Process of Nos2 and COX2 in Stroma tumor interaction

Division Of Basic Sciences - Nci

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Abstract

Angiogenesis and Matrix Remodeling Tumor angiogenesis, growth, and metastasis require matrix degradation and remodeling to facilitate cell migration and neovascularization processes. Three major groups of proteases that regulate angiogenesis are MMPs, cathepsin cysteine proteases, and serine proteases. Among the MMPs; MT1-MMP, MMP-2, and, MMP-9, are considered as important regulators of angiogenesis in many pathologies including cancer. We have shown NO regulation of MMP-9 in murine macrophages, which involved cGMP/pERK mediated suppression of TIMP-1. In addition, higher NO concentrations such as those present in activated macrophages suppress MMP-9 activity, due to nitrosation of the enzyme, and provides a unique mechanism for regulation of this zymogen. Importantly, NO activation of MMP-9 in macrophage conditioned media stimulated vascular cell migration in a muscle explant angiogenesis assay, which was inhibited by silencing of macrophage MMP-9 protein translation prior to NO exposure. It was further shown that exogenous TSP-1 blocked both NO-mediated MMP activation and TIMP-1 suppression. Thus, TSP-1 suppresses NO-mediated angiogenic response in both macrophage and endothelial cell models. We have expanded this model to better understand the role of NO in Alzheimer's disease with Dr. Carol Colton. It was shown that that NO levels reduced TIMP1 as well as modifying inhibiting its MMP inhibitory activity resulting reduction of Abeta plaques in the murine models. In the significant murine model of AD, consisted of APP overexpression to develop plaques and NOS2 depletion recapitulating the full human AD pathology. Thus, in cancer NOS2 has negative impact while in AD NOS2 has a positive effect. Following injury, macrophages are recruited into the wounded tissue bed during the initial stage of inflammation. A previous report has shown that TSP-1 overexpression in human melanoma cells increases ROS production and M1 differentiated macrophage recruitment in tumor xenografts. This observation demonstrates a role of TSP-1 in anti-tumor immunity and therefore suggests selection favoring the loss of TSP-1 during cancer progression. During Th1/Th2 transition of wound response, NO will scavenge ROS as well as suppress TSP-1, which suggests that NO donors could decrease M1 polarization and trigger M2 resolution phase and tissue restoration. This concept is important in chronic inflammation as it's associated with the progression and treatment of cancer and will provide new opportunities in drug development and therapeutic strategy. Immune tumor interaction shapes the the tumor microenvironment that leads to poor outcome. Multiple immunosuppressive mechanisms exist in the tumor microenvironment that drive poor outcomes and decrease treatment efficacy. The co-expression of NOS2 and COX2 is a strong predictor of poor prognosis in ER- breast cancer and other malignancies. Together, they generate pro-oncogenic signals that drive metastasis, drug resistance, cancer stemness, and immune suppression. Using an ER- breast cancer patient cohort, we found that the spatial expression patterns of NOS2 and COX2 with CD3+CD8+PD1- T effector (Teff) cells formed a tumor immune landscape that correlated with poor outcome. NOS2 was primarily associated with the tumor-immune interface, whereas COX2 was associated with immune desert regions of the tumor lacking Teff cells. A higher ratio of NOS2 or COX2 to Teff was highly correlated with poor outcomes. Spatial analysis revealed that regional clustering of NOS2 and COX2 was associated with stromal-restricted Teff, while only COX2 was predominant in immune deserts. Examination of other immunosuppressive elements, such as PDL1/PD1, Treg, B7H4, and IDO1, revealed that PDL1/PD1, Treg and IDO1 were primarily associated with restricted Teff, whereas B7H4 and COX2 were found in tumor immune deserts. Regardless of the survival outcome, other leukocytes, such as CD4 T cells and macrophages, were primarily in stromal lymphoid aggregates. Finally, in a 4T1 model, COX2 inhibition led to a massive cell infiltration, thus validating the hypothesis that COX2 is an essential component of the Teff exclusion process and, thus, tumor evasion. Our study indicates that NOS2/COX2 expression plays a central role in tumor immunosuppression. Our findings indicate that new strategies combining clinically available NOS2/COX2 inhibitors with various forms of immune therapy may open a new avenue for the treatment of aggressive ER-breast cancers.