Abstract 4779: The effects of glutamine deprivation on ovarian cancer initiation and progression
Authors: Ferri-Borgogno Sammy , Lu Kathryn , Gamal Basant T. , Yeung Chi Lam Au , Seeley Erin , Gomez Javier A. , Basi Akshay , Burks Jared K. , Animasahun Olamide , Nagrath Deepak , Mok Samuel C. 
Published: March 2024

Abstract
High-grade serous ovarian cancer (HGSC) is the most common subtype of ovarian cancer. Most patients with HGSC are diagnosed at advanced stage diseases. Despite the high response rate to platinum/taxane-based chemotherapy, most of these patients will develop recurrent chemoresistant disease. Recent studies showed the cancer associated fibroblasts (CAFs) in the tumor microenvironment (TME) play an important role in modulating the malignant phenotypes of HGSC. CAFs are primarily responsible for producing factors such as cytokines and growth factors to modify the TME niche to promote the malignant phenotypes of cancer cells. Recently, we have identified a previously unrecognized mechanism in which metabolism of reactive CAFs is reprogrammed through an upregulated glutamine anabolic pathway in HGSC. This dysfunctional CAF metabolism confers atypical metabolic flexibility and adaptive mechanisms in CAFs, allowing them to harness carbon and nitrogen from noncanonical sources to synthesize glutamine in nutrient-deprived conditions existing in the TME. Our preliminary data show that tumors developed from syngeneic fallopian epithelial cell-derived cancer cells injected IP into C57BL/6 mice, which started to be fed with normal diet two weeks before tumor cells injection had significantly higher tumor burden than those fed with the glutamine-deprived diet. Moreover, tumor-bearing mice treated with glutaminase inhibitor for 3 weeks demonstrated significantly lower tumor burden than those treated with the control vehicle. These findings suggest that the interplay between CAFs and HGSC cells enriches glutamine in the ovarian TME; and glutamine depletion can not only suppress ovarian tumor growth but also prevent the development of advanced progressive diseases. In addition to the direct promoting effect of glutamine on the glutamine addicted HGSC cells, increased CAF-derived glutamine can also affect the activity of other stromal cell types such as immune cells in the TME, which subsequently modulate HGSC cell growth. Imaging mass cytometry (IMC) and Mass Spectrometry Imaging (MSI) were performed on serial tissue sections of tissue microarrays generated from the abovementioned murine samples. Mice fed with a glutamine-deprived diet or treated with the glutaminase inhibitor not only have a significantly lower tumor burden but also induced dramatic changes in the cellular and molecular composition within the TME. In particular, mice fed with a glutamine-deprived diet had greater B-cell-related immune response, reduced stemness, and EMT of ovarian cancer cells, and more activated CAFs, which may result in increased stiffness of the ECM and subsequently enhance the malignant phenotype of HGSC cells. Further studies to delineate the molecular mechanisms by which spatial cellular and metabolic profiles modulate HGSC pathogenesis and progression are warranted.
Citation Format: Sammy Ferri-Borgogno, Kathryn Lu, Basant T. Gamal, Chi Lam Au Yeung, Erin Seeley, Javier A. Gomez, Akshay Basi, Jared K. Burks, Olamide Animasahun, Deepak Nagrath, Samuel C. Mok. The effects of glutamine deprivation on ovarian cancer initiation and progression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4779.