Curcumin sensitizes human gastric cancer cells to 5-fluorouracil through inhibition of the NFκB survival-signaling pathway

Fluorouracil (5-FU) is the most commonly used chemotherapeutic agent for gastric cancer (GC). However, the occurrence of resistance to 5-FU treatment poses a major problem for its clinical efficacy. In this study, we found that the NFκB-signaling pathway can mediate 5-FU resistance in GC cells. We developed a 5-FU-resistant GC cell line named SGCR/5-FU and found that the 5-FU-induced resistance increased cytosolic IκBα degradation and promoted NFκB nuclear translocation in GC cells. These findings were further confirmed by the activation of the NFκB survival-signaling pathway in clinical specimens. Curcumin, a natural compound, can reverse 5-FU resistance and inhibits proliferation in GC cells by downregulating the NFκB-signaling pathway. Moreover, it can also decrease the expression level of TNFα messenger RNA. Flow cytometry and Western blot analysis results showed that the combination of curcumin and 5-FU caused synergistic inhibition of growth and induction of potent apoptosis in the resistant cancer cell lines in vitro. In conclusion, our results demonstrate that the combination of 5-FU and curcumin could be further developed as a potential therapy for human GC.