Browsing by Author "Lim, Felicia"

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    Development and Characterization of a Luciferase Labeled, Syngeneic Murine Model of Ovarian Cancer.
    (Cancers, 2022-08) Russell, Shonagh; Lim, Felicia; Peters, Pamela N; Wardell, Suzanne E; Whitaker, Regina; Chang, Ching-Yi; Previs, Rebecca A; McDonnell, Donald P
    Despite advances in surgery and targeted therapies, the prognosis for women with high-grade serous ovarian cancer remains poor. Moreover, unlike other cancers, immunotherapy has minimally impacted outcomes in patients with ovarian cancer. Progress in this regard has been hindered by the lack of relevant syngeneic ovarian cancer models to study tumor immunity and evaluate immunotherapies. To address this problem, we developed a luciferase labeled murine model of high-grade serous ovarian cancer, STOSE.M1 luc. We defined its growth characteristics, immune cell repertoire, and response to anti PD-L1 immunotherapy. As with human ovarian cancer, we demonstrated that this model is poorly sensitive to immune checkpoint modulators. By developing the STOSE.M1 luc model, it will be possible to probe the mechanisms underlying resistance to immunotherapies and evaluate new therapeutic approaches to treat ovarian cancer.
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    Inhibition of estrogen signaling in myeloid cells increases tumor immunity in melanoma.
    (The Journal of clinical investigation, 2021-12) Chakraborty, Binita; Byemerwa, Jovita; Shepherd, Jonathan; Haines, Corinne N; Baldi, Robert; Gong, Weida; Liu, Wen; Mukherjee, Debarati; Artham, Sandeep; Lim, Felicia; Bae, Yeeun; Brueckner, Olivia; Tavares, Kendall; Wardell, Suzanne E; Hanks, Brent A; Perou, Charles M; Chang, Ching-Yi; McDonnell, Donald P
    Immune checkpoint blockade (ICB) therapies have significantly prolonged patient survival across multiple tumor types, particularly in melanoma. Interestingly, sex-specific differences in response to ICB have been observed, with males receiving a greater benefit from ICB than females, although the mechanism or mechanisms underlying this difference are unknown. Mining published transcriptomic data sets, we determined that the response to ICBs is influenced by the functionality of intratumoral macrophages. This puts into context our observation that estrogens (E2) working through the estrogen receptor α (ERα) stimulated melanoma growth in murine models by skewing macrophage polarization toward an immune-suppressive state that promoted CD8+ T cell dysfunction and exhaustion and ICB resistance. This activity was not evident in mice harboring macrophage-specific depletion of ERα, confirming a direct role for estrogen signaling within myeloid cells in establishing an immunosuppressed state. Inhibition of ERα using fulvestrant, a selective estrogen receptor downregulator (SERD), decreased tumor growth, stimulated adaptive immunity, and increased the antitumor efficacy of ICBs. Further, a gene signature that determines ER activity in macrophages predicted survival in patients with melanoma treated with ICB. These results highlight the importance of E2/ER signaling as a regulator of intratumoral macrophage polarization, an activity that can be therapeutically targeted to reverse immune suppression and increase ICB efficacy.