Laight, B. J. | Search bioRxiv

bioRxiv2024

Fes-deficient macrophages enhance CD8+ T cell priming and tumour control through increased proinflammatory cytokine production and presentation

Homeostatic immunoregulatory mechanisms that prevent adverse effects of immune overaction can serve as barriers to successful anti-cancer immunity, representing attractive targets to improve cancer immunotherapy. Here, we demonstrate a novel role of the Fes tyrosine kinase, abundantly expressed in immune cells, as an innate intracellular immune checkpoint. Host Fes-deficiency delays tumour onset in a gene dose-dependent manner and improves murine triple negative breast cancer and melanoma tumour control, survival, doxorubicin efficacy, and anti-PD-1 therapy sensitization. These effects were associated with a shift to an anti-tumourigenic tumour immune microenvironment. In vitro, we observed increased Toll-like receptor signaling, and proinflammatory cytokine production and presentation from antigen presenting cells, leading to increased T cell activation, cancer cell killing and tumour control. This study highlights Fes as a novel innate immune checkpoint with potential as a predictive biomarker for effective immune checkpoint blockade treatment, and a potential therapeutic target to improve anti-cancer immunotherapy.

immunology↗

bioRxiv2022

PTEN and BRCA1 tumor suppressor loss associated tumor immune microenvironment exhibits differential response to therapeutic STING pathway activation in a murine model of ovarian cancer

BackgroundHigh grade serous ovarian carcinoma (HGSC) is the most lethal gynecologic malignancy characterized by chemoresistance and high rates of recurrence. HGSC tumors display a high prevalence of tumor suppressor gene loss. Loss of BRCA1 and PTEN function due to mutations or epigenetic influence have been widely associated with variable clinical outcomes, where tumors with BRCA1 mutations exhibit increased chemosensitivity and those with PTEN mutations have been reported to exhibit chemoresistance. Given the established type 1 interferon regulatory function of BRCA1 and PTEN genes and associated contrasting T cell infiltrated and non-infiltrated tumor immune microenvironment (TIME) states, in this study we investigated the potential of Stimulator of Interferon Genes (STING) pathway activation in improving overall survival via enhancing chemotherapy response, specifically in tumors with PTEN deficiency. MethodsExpression of PTEN protein was evaluated in tissue microarrays generated using pre-treatment tumors collected from a cohort of 110 patients with HGSC. Multiplex immunofluorescence staining was performed to determine spatial profiles and density of selected lymphoid and myeloid cells. In vivo studies using the syngeneic murine HGSC cell lines, ID8-Trp53-/-; Pten-/-and ID8-Trp53-/-; Brca1-/-, were conducted to characterize the TIME and response to carboplatin chemotherapy in combination with exogenous STING activation therapy. ResultsTumors with absence of PTEN protein exhibited a significantly decreased disease specific survival and intra-epithelial CD68+ macrophage infiltration as compared to intact PTEN expression. In vivo studies demonstrated that Pten deficient ovarian cancer cells establish an immunosuppressed TIME characterized by increased proportions of M2-like macrophages, GR1+ MDSCs in the ascites, and reduced effector CD8+ cytotoxic T cell function compared to Brca1 deficient cells; further, tumors from mice injected with Pten deficient ID8 cells exhibited an aggressive behavior due to suppressive macrophage dominance in the malignant ascites. In combination with chemotherapy, exogenous STING activation resulted in longer overall survival in mice injected with Pten deficient ID8 cells, reprogrammed intraperitoneal M2-like macrophages derived from Pten deficient ascites to a M1-like phenotype and rescued CD8+ cytotoxic T cell activation. ConclusionsThis study reveals the importance of considering the influence of cancer cell intrinsic genetic alterations on the TIME for therapeutic selection. We establish the rationale for the optimal incorporation of interferon activating therapies as a novel combination strategy in PTEN deficient HGSC.

immunology↗