Abstract 2957: Nasopharyngeal cancer

Abstract

Abstract Background: Nasopharyngeal cancer (NPC) is associated with a poor survival rate. The ability of cancer cells to evade apoptosis and exhibit limitless replication potential allows for the progression of cancer. The aim of this study was to investigate in vitro the effect of the isoflavone phenoxodiol on human NPC cell line and T cells, which has previously been shown to inhibit cell proliferation and promote apoptosis in a range of cancer cell lines and in anti-CD3/anti-CD28-activated murine splenocytes. Methods: Four NPC cancer cell lines-C666, C17, and paired NPC43 EBV-positive and its respective EBV-negative cell lines were cultured in vitro, and then treated with phenoxodiol for 72h or 5 days. The migration and proliferation was investigated by transwell and XTT, respectively. Conditioned medium of treated NPC cell lines were collected and incubated with human PBMC for 5 days. CD4 and CD8 surface staining were analyzed by flow cytometry. Result: We demonstrated that phenoxodiol inhibited NPC migration and cell proliferation (IC50 4µM). Among all the NPC cell lines, the proliferation effect on EBV-negative cell line (NPC43-ve) is least responsive to phenoxodiol. A dose-dependent of apoptosis in NPC cell lines by phenoxodiol [early apoptotic cells (Annexin V+/PI- at 1µM); late apoptotic cells (Annexin V+/PI+ at 2µM), and necrotic cells (Annexin V-/PI+, at 4µM) were distinguished. Interestingly, phenoxodiol reduced frequency of CD4 T cells while promoting the number of CD8 T cells. Conclusions: Phenoxodiol demonstrates an ability in NPC cancer cells to induce its apoptosis while inhibit its migration and proliferation. Moreover, the ability of phenoxodiol to modulate T cells population indicates that phenoxodiol would be effective as a potential future treatment for NPC. Note: This abstract was not presented at the meeting. Citation Format: Ngar Woon Kam, See Wing Chan, George Sai-Wah Tsao, Xin-Yuan Guan, Dora Lai Wan Kwong. Nasopharyngeal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2957.