Abstract 1040: Blocking hypoxia-induced carbonic anhydrases 9 enhances sensibility to cisplatin of head and neck squamous carcinoma

Abstract

Abstract The head and neck squamous carcinomas (HNSSCs) are the sixth most common cancer worldwide. Given the heterogeneous nature of HNSCC, this carcinoma results in higher resistance to chemoradiotherapy. Recent evidence highlight the importance of the hypoxic microenvironment in contributing to cisplatin resistance. Therefore, the aim of this study was to investigate the role played by hypoxia-induced protein carbonic anhydrase 9 (CA9) in supporting HNSCC cisplatin resistance. Furthermore, we purpose to investigate the ability of CA9 inhibitor, SLC-0111, a small molecule already used in Phase I clinical trial, to sensitize HNSSC cells to chemotherapy in vitro and in vivo. We analyzed the expression of CA9 in a public data set of 103 HNSCC samples and 22 oral cavity normal tissues and in two HNSSC cell lines (FaDu; SCC-011). HNSCC cells grown in 2D and 3D models under hypoxic conditions (1% O2) showed increased levels of CA9 and greater resistance to cisplatin than cells grown under normoxic conditions. The addition of CA9 inhibitor SLC-0111 to cisplatin sensitized cells to the chemotherapeutic agent and caused a reduction of colony number, spheroid formation, tumor cell, and spheroid migration and invasiveness. Furthermore, the combination therapy hampered activation of STAT3, AKT, ERK, and EMT program whereas it induced apoptosis. Notably, the combined treatment caused inhibition of tumor growth and induction of apoptosis in HNSCC subcutaneous xenografts, as assessed by high-frequency ultrasonography and fluorescent molecular tomography (FMT) with NIR-Annexin V, respectively, at a higher extent than single agents. In addition, FMT with NIR-Prosense revealed a stronger reduction of lymph nodes metastases when mice bearing orthotopic xenografts were treated with cisplatin plus SLC-0111 with respect to a single treatment. Our findings taken together demonstrate the crucial role played by CA9 in promoting cisplatin resistance in HNSCC and the efficacy of SLC-0111 to sensitize tumor cells and xenografts to chemotherapy. Citation Format: Annachiara Sarnella, Ylenia Ferrara, Luigi Auletta, Sandra Albanese, Vincenzo Alterio, Jean-Yves Winum, Claudiu T Supuran, Laura Cerchia, Giuseppina De Simone, Antonella Zannetti. Blocking hypoxia-induced carbonic anhydrases 9 enhances sensibility to cisplatin of head and neck squamous carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1040.