Abstract 6766: Tetraarsenic hexoxide augments the anticancer effects of Artemisia annua polyphenols on both naive and oxaliplatin-resistant HCT116 colorectal cancer cells by downregulating CD44, EGFR and cyclinD1, and increasing DNA damages and intra

Abstract We previously demonstrated that polyphenols extracted from Korean Artemisia annua L. (pKAL) exerted stronger anticancer activity on oxaliplatin-resistant HCT116 colorectal cancer cells (Oxp-R-HCT 116 cells) than parental HCT116 cells (p-HCT 116 cells). We also demonstrated tetraarsenic hexoxide exerts anticancer activity of pKAL on several cancer cell lines by suppressing NF-κB activity. In this study, we found that tetraarsenic hexoxide significantly enhanced the anticancer activity of pKAL on both Oxp-R-HCT 116 cells and p-HCT 116 cells. The aim of this study is to elucidate how tetraarsenic hexoxide enhance the anticancer effects of pKAL on Oxp-R-HCT 116 cells. CCK-8 assay, phase-contrast microscopy analysis, and morphological analysis with hematoxylin stain revealed that the anticancer effect of pKAL is more enhanced by tetraarsenic hexoxide on Oxp-R-HCT 116 cells even though anticancer effect of tetraarsenic hexoxide alone was not prominent on Oxp-R-HCT 116 cells. This phenomenon was not associated with suppression of some of oxaliplatin resistance-related upregulated proteins (Oxp-RR-Proteins) (β-catenin, neuclephosmin, and SOD), but was associated downregulation of cell survival- and stemness-related proteins (NF-κB, cyclin D1, EGFR, and CD44) that were not up-regulated in Oxp-R-HCT 116 cells. In addition, tetraarsenic hexoxide and pKAL combination treatment enhanced anticancer effect by induction of DNA damage and intracytoplasmic vesicles suggesting autophagic cell death.The detailed western blot analysis for anti-cancer effects of tetraarsenic hexoxide alone did not strongly suppress the expression of β-catenin(one of oxaliplatin resistance-related upregulated proteins) in p-HCT 116 cells as well as Oxp-R-HCT 116 cells while pKAL alone strongly suppressed it. In addition, tetraarsenic hexoxide and pKAL combination treatment enhanced LC3B and P62 while pKAL alone did not enhance them. N-acetylcysteine (NAC) strongly suppressed anticancer effect of induction of DNA damage and intracytoplasmic vesicles that suggested autophagic cell death on Oxp-R-HCT 116 cells. In conclusion, this study suggests that tetraarsenic hexoxide enhanced the anti-cancer effects pKAL by suppressing CD44, EGFR, and cyclin D1, and increasing DNA damages and intracellular vesicles that suggested autophagic cell death. In addition, the anticancer effects of tetraarsenic hexoxide on OXP-R-Hct 116 cells might be associated with cell survival related and ROS pathway, but not associated with downregulating Oxp-RR-Proteins of Oxp-R-HCT 116 cells. Citation Format: Won Sup Lee, Eun Joo Jung, Hye Jung Kim, Sung Chul Shin, Gon Sup Kim, Jin-Myung Jung. Tetraarsenic hexoxide augments the anticancer effects of Artemisia annua polyphenols on both naive and oxaliplatin-resistant HCT116 colorectal cancer cells by downregulating CD44, EGFR and cyclinD1, and increasing DNA damages and intracellular vesicles [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 6766.