O226: OTD is cytotoxic to A-375 melanoma cells without compromising fibroblast migratory wound healing function – a potential role in perioperative melanoma surgery

Abstract

Abstract Introduction Melanoma incidence is increasing with 325,000 new cases reported in 2020 worldwide and 57,000 deaths. High recurrence rates are associated with prolonged inflammation and subsequent immunosuppression post-operatively. Surgical adjuvants may play a role in mitigating these adverse immune responses while increasing the cytotoxicity of cancer cells. Our previous research demonstrated anti-inflammatory effects of 1,4,5-oxathiazinane-4,4-dioxide (OTD) on Human Dermal Fibroblasts (HDFs) by the reduction of cytokine production. This study evaluates its cytotoxicity on melanoma cells. Methods OTD treatments of 0.25mM, 0.5mM, 0.75mM, 1mM and 1.25mM were applied to A-375 primary melanoma cells in triplicate for 24h and an MTT assay assessed cell viability. The absorbance was measured at 570nm wavelength. Cell viability was expressed as a percentage of the control. Results were compared using one-way analysis of variance (ANOVA) with GraphPad Prism software. Results Application of OTD treatments demonstrated a cytotoxic effect on melanoma cells at all concentrations. Relative optical density (OD) value was compared for each concentration against the control. A significant difference in cytotoxicity, relative to untreated control, was observed for each concentration; 56.8% at 0.25mM OTD (p*** = 0.001) and 68 to 71.6% at 0.5mM to 1.25mM OTD (p****<0.001). Conclusion OTD induces cytotoxicity in primary melanoma cells at all concentrations. Whereas our previous research demonstrated at 0.75mM it reduced inflammatory cytokine production in HDFs without adversely affecting migration. Therefore, OTD as a surgical adjuvant has the potential to be cytotoxic towards primary melanoma cells, reduce HDF inflammation and preserve migratory wound healing function.