Abstract 1111: Poor radiation sensitivity and potential radiosensitizers for betel-nuts related head and neck squamous cell carcinoma in Taiwan

Abstract

Abstract Background: Betel nut chewing might contribute to strong invasion & treatment refractoriness in HNSCC from Taiwan. Betel-nuts exposed HNSCC cell line, TW2.6, had high PDL1, defective p53 mutation, p16 loss, & BCL2 overexpression. In our studies, PI3K/AKT/mTOR inhibitors, anti-angiogenesis therapies, CDK4/6 inhibitors, DDR interventions, epigenetic modifications, and immunotherapy-containing regimens will be future combination options. The genomic signature of TW2.6 has been figured out in our study(AACR2020 & 2023), too, mainly with PIK3CA H1047R mutation, high TMB(8.42 muts/Mb)/MSS, VEGF-A amplification, p53/MYC/HRAS/DDR2/PDGFRbeta/EPHB1/ATM mutations, FAT1 loss, amplification of TERT/FGF10/CCND3/SOX9/IL-7R/SDHA/RICTOR/FLCN, CDK12/PTPRD loss of function, CDK8 mutation, & deletions of STK11/ARID1B/MITF/TNFAIP3 and molecularly-guided novel interventions will be designed. Purpose & Methods: Polo-like kinase 1 inhibitor(volasertib), gluconate(blocking citrate transport & glucose metabolism), IAP inhibitor(Debio1143), glutaminase 1 inhibitor(CB839) were tested on TW2.6 to evaluate synergistic effects with radiation. Results: TW2.6 was resistant to volasertib, gluconate, or radiation alone; but sensitive to Debio1143 and CB839. Volasertib significantly enhanced radiation. The flow cytometry revealed volasertib and radiation resulted in a significant G2/M arrest. Western blotting showed volasertib and radiation increased p-histone3, p-CDK1, & cyclin B levels and induced apoptosis. Gluconate, CB839, or Debio1143 each had significant synergistic effects with radiation. The radiosensitization efficacy would be volasertib>gluconate>CB839>Debio1143. Conclusions: In Taiwan, patients with R/M HNSCC progressing within 3 months after CCRT could be rescued by early ICIs. Recently, sequential CCRT followed by ICI or Debio-1143 with CCRT showed potential survival benefits. In our studies, novel agents such as PLK inhibitor, gluconate, and CB839 had even better radiosensitization compared with Debio1143. Sequential CCRT with novel agents followed by ICI will be the future trend, esp. in biology-aggressive betel-nuts related locally advanced HNSCC in Taiwan. Citation Format: Jo-Pai Chen, Jui-Ying Chang, Ruey-Long Hong. Poor radiation sensitivity and potential radiosensitizers for betel-nuts related head and neck squamous cell carcinoma in Taiwan [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 1111.