Abstract 1749: The synergic effect of cisplatin and a chemokine receptor antagonist sensitizes drug resistant gastric cancer cells and inhibits tumoroid formation

Abstract

Abstract Introduction: Gastric cancer (GC) is an important cause of death worldwide. Cisplatin (CDDP) is the most used drug in the chemotherapy of advanced GC. However, CDDP resistance reduces GC survival. The CCR5/CCL5 axis has been associated with GC development, but its role in CDDP resistance in GC has not been elucidated. The aim of this study was to determine the effects of CCR5/CCL5 axis blockade by a chemokine receptor antagonist (CRA), alone and in combination with CDDP, on in vitro and 3D tumorid models from AGS R-CDDP cells. Methodology: AGS R-CDDP cells (CDDP-resistant human gastric adenocarcinoma cells) were previously established using a stepwise drug dosing protocol and characterized. CCL5 was selected through transcriptomic analysis and its expression level was validated by qRT-PCR. Cytotoxicity assays were determined by using MTT. Apoptosis and cell cycle assays were evaluated by flow cytometry. Tumoroid formation was performed from AGS R-CDDP cells in low adhesion plates (NunclonTMSpheraTM). After 10 days in culture, tumoroid >150 µm in diameter were scored and pharmacological stimuli were added on days 14, 17 and 20. CRA was used alone and in combination with CDDP in all assays. Results: CRA/CDDP combination triggered a re-sensitized phenotype in AGS R-CDDP cells, decreasing cell viability but not increasing apoptosis compared to independent treatments. AGS R-CDDP cells treated with CRA/CDDP were mainly arrested in S phase. CCL5 showed a decrease in mRNA levels after the CRA/CDDP combination compared to separate treatments. AGS R-CDDP cells showed a higher potential in the ability to form tumoroids compared to AGS WT cells. Finally, CRA/CDDP combination inhibited tumoroid formation compared to independent treatments. Discussion and Conclusion: CCL5 showed a decrease in mRNA levels after the CRA/CDDP combination, possibly correlating with allosteric inhibition of the CCR5 receptor. CRA/CDDP combination has a synergic effect that sensitizes AGS R-CDDP cells and inhibits tumoroid formation. This combination could be used as a potential coadjuvant in GC therapy allowing to reduce the doses of CDDP and therefore to reduce side effects. Citation Format: Bárbara Mora-Lagos, María Elena Reyes, Lorena Lobos-Gonzalez, Matías del Campo, Carmen Gloria Ili, Kurt Buchegger, Yuselin Mora, Louise Zanella, Ismael Riquelme, Priscilla Brebi. The synergic effect of cisplatin and a chemokine receptor antagonist sensitizes drug resistant gastric cancer cells and inhibits tumoroid formation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1749.