Chemopreventive effects of FITOPROT against 5-fluorouracil-induced toxicity in HaCaT cells

Aims This study evaluated the mechanisms involved in the chemopreventive effects of a mucoadhesive formulation (FITOPROT), containing curcuminoids from Curcuma longa L. (Zingiberaceae) and Bidens pilosa L. (Asteraceae) extract, against 5-FU-induced cellular toxicity using an in vitro oral mucositis model. Main methods Effects of FITOPROT on 5-FU-induced cytotoxicity in HaCaT and SSC-4 cells were evaluated by MTT assay. For mechanistic analyses, HaCaT cells were first pretreated with FITOPROT (0.005%) for 24 h followed by treatment with FITOPROT and simultaneously exposed to 5-FU (10 μg/mL) for additional 24 h. Key findings FITOPROT was able to protect HaCaT cells from 5-FU-triggered cell damage. Moreover, the FITOPROT + 5-FU association showed higher cytotoxic effects on SSC-4 cancer cells. Flow cytometry and/or fluorescence microscopy analysis showed FITOPROT was able to significantly reduce ROS generation and prevent mitochondrial changes in HaCaT cells. In addition, it avoided the release of cytochrome c from mitochondria to the cytoplasm in cells exposed to 5-FU, and restored their proliferative activity via Ki-67 expression. Furthermore, FITOPROT regulated 5-FU-induced oxidative stress via Nrf2 involvement. HaCaT cells pretreated/treated with FITOPROT also showed normal expression of TNF-R1 and NF-κB inflammatory proteins and decreased levels of pro-inflammatory cytokines (TNF, IL-1β, IL-6 and IL-8). Moreover, a high-resolution liquid chromatography-mass spectrometry analysis showed the presence of flavonoids rutin, glucoronylated quercetin and dimethylquercetin rutenoside in FITOPROT. Significance It was showed that FITOPROT, an antioxidant phytochemicals-rich mucoadhesive formulation, exerts chemopreventive effects against 5-FU-triggered toxicity through antioxidant and anti-inflammatory mechanisms and restoration of proliferative capacity in HaCaT cells.