Inhibiting WNT Ligand Production for Improved Immune Recognition in the Ovarian Tumor Microenvironment.

Whitney N Goldsberry,Lyse A Norian,Ashwini A Katre,Troy D Randall,Rebecca C Arend,Angelina I Londoño,Michael J Birrer,Sara J Cooper,Jaclyn A Wall,Nidhi Goel,Selene Meza-Perez,Brandon M Roane,Bryan T Mott

doi:10.3390/cancers12030766

Whitney N Goldsberry, Lyse A Norian + Show 11 more

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https://doi.org/10.3390/cancers12030766

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Abstract

In ovarian cancer, upregulation of the Wnt/β–catenin pathway leads to chemoresistance and correlates with T cell exclusion from the tumor microenvironment (TME). Our objectives were to validate these findings in an independent cohort of ovarian cancer subjects and determine whether inhibiting the Wnt pathway in a syngeneic ovarian cancer murine model could create a more T-cell-inflamed TME, which would lead to decreased tumor growth and improved survival. We preformed RNA sequencing in a cohort of human high grade serous ovarian carcinoma subjects. We used CGX1321, an inhibitor to the porcupine (PORCN) enzyme that is necessary for secretion of WNT ligand, in mice with established ID8 tumors, a murine ovarian cancer cell line. In order to investigate the effect of decreased Wnt/β–catenin pathway activity in the dendritic cells (DCs), we injected ID8 cells in mice that lacked β–catenin specifically in DCs. Furthermore, to understand how much the effects of blocking the Wnt/β–catenin pathway are dependent on CD8+ T cells, we injected ID8 cells into mice with CD8+ T cell depletion. We confirmed a negative correlation between Wnt activity and T cell signature in our cohort. Decreasing WNT ligand production resulted in increases in T cell, macrophage and dendritic cell functions, decreased tumor burden and improved survival. Reduced tumor growth was found in mice that lacked β–catenin specifically in DCs. When CD8+ T cells were depleted, CGX1321 treatment did not have the same magnitude of effect on tumor growth. Our investigation confirmed an increase in Wnt activity correlated with a decreased T-cell-inflamed environment; a relationship that was further supported in our pre-clinical model that suggests inhibiting the Wnt/β–catenin pathway was associated with decreased tumor growth and improved survival via a partial dependence on CD8+ T cells.

Highlights

Ovarian cancer persists as the deadliest gynecologic malignancy in the United States
12, 766 pharmacologically via use of the PORCN inhibitor IWP-L6 [29]. These findings indicate that therapeutic intervention to reduce Wnt/β-catenin signaling may alter the tumor microenvironment (TME) in ovarian cancer, reduce Wnt/β-catenin signaling may alter the TME in ovarian cancer, allowing an increase in tumor-infiltrating lymphocytes (TILs), allowing an increase in TILs, resulting in an inflamed state, which has been shown to correlate with resulting in an inflamed state, which has been shown to correlate with improved outcomes
Cold tumors and tumors with activating Wnt mutations and/or higher Wnt/β-catenin pathway activity have been shown to have a poorer prognosis, we sought to investigate whether the influence of chemotherapy changed either of these and if so, how this correlated with patient outcomes (Figure S1e) [4,7,11]

Summary

Introduction

Ovarian cancer persists as the deadliest gynecologic malignancy in the United States. In order to improve the poor clinical response rates to immunotherapies, there is an urgent need to identify strategies that cause the TME to become “hotter,” by increasing T cell infiltration or decreasing. When tumor-infiltrating lymphocytes (TILs) remain present and activated this creates a hot TME, which has been correlated with improved prognosis and with increased sensitivity to chemotherapeutic treatment in high grade serous ovarian carcinoma (HGSC) [7,8]. Tregs act to inhibit the function of cytotoxic T cells (CTL), and are tumor-promoting and lead to decreased chemotherapy sensitivity [9]. High levels of CD4+ Tregs may lead to the exclusion of CD8+ T cells, and the CD8+ /Treg ratio has been shown to be predictive of overall survival in ovarian cancer [10]. While CD4+ and CD8+ T cells are important factors in the TME, there are many additional immune cells, such as macrophages and dendritic cells (DCs) that are critical in determining the ability of the immune system to control tumor progression

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