Abstract 5416: Purinergic P2Y6 receptor antagonists as potential anti tumor agents
Authors: Ghimeray Khagendra , Sharma Shilpa , Akundi Ravi Shankar 
Published: March 2024

Introduction: Cancer places a tremendous strain on society in both developed and economically less developed nations. It remains the most recurring and deadliest disease despite rapid advances in treatment modalities. The major contributors are the prevalence of known risk factors, urbanization, population growth and ageing. Cancer resurgence depends on the organ in which the tumor first appears, immune response, patient’s characteristics, disease stage and tumor microenvironment (TME). Among the several inflammatory molecules found within the TMEs, the levels of adenosine triphosphate (ATP) has been found to be high. In healthy tissue, the concentration of ATP in the extracellular space (eATP) is negligible and does not accumulate significantly due to the activity of ectonucleotidases. However, tissue injury, cellular stress and chemotherapy mediated cell death can increase the levels of ATP in the TME. The eATP exerts its effect mainly through purinergic P2 receptors expressed by most malignant cells. We have previously shown that eATP promoted migration and invasion of cancer cells in vitro through increased expression of the enzyme cyclooxygenase 2 (COX-2) (Sharma et al., 2021). We showed that eATP mediated COX-2 expression is through P2 receptors (Akter et al., 2021). Accordingly, we hypothesized that blocking the P2 receptors would abolish the COX-2-mediated migration of tumor cells and tested the same in an animal model.

Methodology: Tumors were generated in 8-15-week-old male C57BL/6 mice (20-25 g weight) through subcutaneous injection of syngeneic EL4 lymphoma cells in the left flank of the mice. When tumors were palpable around day 10, saline or P2 receptor, antagonists were directly injected into the center of the tumor and mice were divided into three groups: saline (vehicle control), suramin (broad-spectrum P2 receptor antagonist), and MRS 2578 (P2Y6 receptor-specific antagonist). Drugs were chosen based on prior in vitro research and a vernier caliper was used to assess the growth of the tumor every day. Behavioral tests were performed on day 8 (prior to P2 receptor injections) and days 11, 14 and 17 post-tumor injection. Mice were continuously monitored for their health and were sacrificed on day 18 with deep CO2 anesthesia and cervical dislocation.

Results: We found that suramin-injected tumors had a substantial reduction in tumor volume when compared to saline-injected ones. Intra-tumoral injections of P2 receptor antagonists such as MRS-2578 also resulted in similar outcomes as suramin. In tumors treated with P2 receptor antagonists, the expression of COX-2, cell cycle proteins and epithelial-to-mesenchymal (EMT) markers, which aid in metastasis, were significantly downregulated, indicating a suppressive effect. Therefore, we propose that P2 receptor-dependent anti-inflammatory drugs (PBAIDs) could be considered a potential alternative therapeutic option for preventing cancer recurrence.

Citation Format: Khagendra Ghimeray, Shilpa Sharma, Ravi Shankar Akundi. Purinergic P2Y6 receptor antagonists as potential anti tumor agents [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 5416.