ABSTRACT Growing evidence indicates that the biological response to chronic social stress and distress can promote the progression of ovarian precursor lesions and invasive cancer development via prolonged activation of the sympathetic nervous system and sustained norepinephrine release. While chronic social stress/distress is known to cause chronic inflammation, key questions remain about how stress-related signaling pathways alter the tumor immune response, particularly infiltration by immunosuppressive cell types triggered in response to chronic inflammation, and potential means of mitigating the impact of chronic social stress/distress on immune function. Specifically, we propose to evaluate the hypothesis that chronic social stress/distress enhances the early and late progression of ovarian tumors by promoting recruitment and activity of immunosuppressive M2-type tumor- associated macrophages (TAM) and myeloid-derived suppressor cells (MDSC) and that certain medications, including aspirin and other NSAIDs, beta-blockers, and statins, can disrupt immune dysregulation triggered by stress/distress. Aim 1 will use data from four long-term prospective cohorts in diverse populations and a population-based case-control study that have collected self-reported measures of chronic social stress and distress (e.g., widowhood, social isolation, depression, anxiety) and ovarian tumor tissue for tissue microarrays. Aim 1 will measure intratumoral immune markers to assess TAM, including polarization from the M1 to the M2 immunosuppressive phenotype, and MDSC infiltration, using multiplex immunofluorescence. We hypothesize that chronic social stress and distress are positively related to ovarian tumor immune suppression (e.g., increased ratio of M2:M1 TAMs, MDSCs) and that the association of these exposures with ovarian cancer diagnosis and associated tumor immune suppression (exploratory) is attenuated among users of aspirin, non- aspirin NSAIDs, beta-blockers, or statins. Using an orthogonal and interactive approach, Aim 2 will use experimental ovarian cancer mouse models to examine the effects of chronic unpredictable and predictable stress occurring before and after inoculation on MDSCs, monocyte, and TAM populations as well as cytokine networks by polychromatic flow cytometry and multiplex assays. We also will examine if aspirin and one other medication informed by the analyses in humans and existing literature counteracts the effects of chronic stress on TAM, MDSCs, and monocyte infiltration, polarization, and tumor progression. We hypothesize that pre- inoculation chronic stress exacerbates post-inoculation chronic stress-induced ovarian cancer progression in mouse models by up-regulating TAM infiltration, M2 polarization, and MDSC infiltration. In addition, we hypothesize that aspirin will abrogate these effects. This innovative application will inform future work to identify women at increased risk for tumoral immune profiles associated with poor prognosis and to develop novel immunopreventive strategies, pharmacotherapies, and psychosocial interventions to prevent and treat invasive ovarian cancer in women who experience chronic social stress and distress.

PROJECT NARRATIVE This application integrates research using human populations and experimental approaches to elucidate how stress-induced signaling pathways alter ovarian tumor-associated immunity, particularly immunosuppressive cell types, and to assess anti-inflammatory medications that may mitigate these effects. Our synergistic approach will shed light on mechanisms by which chronic stress and distress enhance early and late disease progression, and provide new targets for cancer interception.