Brooks, Tayla Rashanaye

Abstract Description Cholangiocarcinoma (CCA) is an aggressive epithelial malignancy of the bile duct, with rising global incidence and poor prognosis. Current treatments achieve only 20-30% response rates in advanced cases, highlighting the need for novel therapeutic approaches. The tumor microenvironment (TME) has emerged as a critical focus for innovative therapies. Sulfatase 2 (SULF2) is a heparan sulfate (HS)-editing enzyme that alters HS chain affinity for growth factors and receptors, modulating heparan sulfate proteoglycans (HSPG) in cell signaling pathways. Specific sulfatases in HSPGs have been implicated as therapeutic targets in CCA. This study investigates the potential of anti-SULF2 antibodies to modulate immune cells within the TME using a C57BL6 syngeneic mouse model. Anti-SULF2-treated mice were compared to untreated controls, with tumors analyzed via CyTOF. Treatment resulted in reduced immunosuppressive cells and increased anti-tumor immune cells, suggesting that SULF2 inhibition shifts the TME toward an anti-tumorigenic state. These findings highlight SULF2 as a promising target for therapeutic intervention. Future studies will explore spatial transcriptomic and proteomics to elucidate the interplay between SULF2 expression in the TME makeup. We will also explore the molecular mechanisms of SULF2 suppression and its influence on cytokine signaling pathways within the TME. Funding Sources Supported by CTSA Grant Number TL1 TR002380 from the National Center for Advancing Translational Science (NCATS). Topic Categories Tumor Immunology: Cellular Responses and Tumor Microevironment (TIME)

Abstract Medical researchers are increasingly prioritizing the inclusion of underserved communities in clinical studies. However, mere inclusion is not enough. People from underserved communities frequently experience chronic stress that may lead to accelerated biological aging and early morbidity and mortality. It is our hope and intent that the medical community come together to engineer improved health outcomes for vulnerable populations. Here, we introduce Health Equity Engineering (HEE), a comprehensive scientific framework to guide research on the development of tools to identify individuals at risk of poor health outcomes due to chronic stress, the integration of these tools within existing healthcare system infrastructures, and a robust assessment of their effectiveness and sustainability. HEE is anchored in the premise that strategic intervention at the individual level, tailored to the needs of the most at-risk people, can pave the way for achieving equitable health standards at a broader population level. HEE provides a scientific framework guiding health equity research to equip the medical community with a robust set of tools to enhance health equity for current and future generations.

Abstract Cholangiocarcinoma (CCA) is an aggressive epithelial malignancy of the bile ducts. Recent reports have suggested a rise in the incidence of CCA globally. Current treatments for CCA have limited effectiveness, with only 20-30% response rates in patients with advanced cancer. Thus, there is a growing need to investigate new therapeutic targets for CCA. The tumor microenvironment (TME) is a potential target for novel therapies. The TME plays an important role in progression and metastasis of cancer through facilitating immune escape. Recent studies have demonstrated potential roles for heparan sulfate proteoglycans (HSPGs) in tumorigenesis. Sulfatase 2 (SULF2) is a heparan sulfate editing sulfatase that removes the 6-O sulfate moiety within the heparan sulfate (HS) chains and alters the affinity of HS chains for growth factors and cytokines and their receptors, thus modulating HSPG function in cell signaling pathways. HSPG specific sulfatases have been recently identified as a potential therapeutic target in CCA. We aimed to assess the effects of anti-Sulfatase-2 antibody on immune cells in the tumor microenvironment of syngeneic CCA xenografts in C57BL6 mice. Mice bearing syngeneic CCA xenografts were treated with an anti-sulf2 antibody, and the tumors compared to untreated control xenografts. After treatment, the tumors were harvested and analyzed by Cytometry by time of flight (Cytof) to identify changes in the types and numbers of immune cells in the tumor xenografts. Treatment with anti-sulf2 antibody resulted in a decrease in immunosuppressive cells such as tumor associated macrophages (TAMs) and myeloid derived suppressor cells (MDSC) compared to the control. There was also an increase in anti-tumor cells such as T-cells and NK cells, suggesting that suppressing sulf-2 in the microenvironment can shift the TME toward an anti-tumorigenic rather than a pro-tumorigenic environment. In summary, our work demonstrates the potential to target Sulfatase 2 as a therapeutic mechanism for immunomodulation of the tumor microenvironment. Future experiments to determine the relationship between specific clinical phenotypes and the number, activities and types of immune cells seen in the TME, and experiments in other hepatobiliary cancers models, such as hepatocellular carcinoma and gallbladder cancer, will be conducted. Citation Format: Tayla R. Brooks, Nellie Campbell, Melanie Keim, Lewis R. Roberts. Modulating the immune response in cholangiocarcinoma: Targeting sulfatase-2 for therapeutic intervention [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 6525.