Objectives: Improving response rates in colorectal cancer (CRC) is an urgent clinical need. This study aimed to explore the synergistic action of Lebanese rosemary essential oil (REO) and 5-fluorouracil (5-FU) in HCT116 CRC cells.
Methods: We tested the cell viability of monotherapy and combination therapy. The combination index was calculated using CompuSyn software to evaluate drug-drug interactions and the level of synergistic cytotoxicity. We also evaluated cell migration and cytopathology. Furthermore, cell apoptosis-related proteins (i.e. Bax and Bcl-2) were measured by Western blot analysis.
Key findings: The REO/5-FU combination synergistically reduced cell viability, effectively decreased cell migration, and increased the Bax/Bcl-2 ratio in HCT116 cells. This triggered a proapoptotic morphology and initiated an apoptotic cascade in HCT116 cells, as indicated by a higher Bax/Bcl-2 ratio.
Conclusions: Our results provide evidence of the REO/5-FU combination as a better approach to improve 5-FU anticancer efficacy and allow the use of lower 5-FU doses due to the adjuvant effect of REO.
Keywords: 5-fluorouracil; HCT116 colorectal cancer cells; apoptosis; cell migration; rosemary essential oil; survival.
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