Curcumin sensitized the antitumour effects of irradiation in promoting apoptosis of oesophageal squamous-cell carcinoma through NF-κB signalling pathway

ObjectivesTo investigate the potential synergistic effect of curcumin with irradiation (IR) in oesophageal squamous-cell carcinoma (ESCC) and elucidate the underlying molecular mechanisms. MethodsThe ESCC cell lines were established from clinical samples. Cell apoptosis post-treatment was stained by Annexin V/PI staining and analysed by flow cytometry. Cells survived IR was evaluated with clonogenic assay. Xenograft tumour model was established by subcutaneous inoculation, and tumour progression was monitored. The NF-B pathway was characterized by immunoblotting. Key findingsCurcumin enhanced the pro-apoptotic effect of IR in ESCC cells. Pretreatment with curcumin significantly sensitized ESCC cells to IR in a dose-dependent manner. Coadministration with curcumin remarkably extended the median survival time of ESCC xenograft mice while exposed to IR therapy. The xenograft tumour progression was significantly suppressed as well. Mechanistically, curcumin treatment was demonstrated to efficiently inhibited NF-B signalling. ConclusionsWe have well-recapitulated the pathological properties and therapeutic response of ESCC with established cell lines derived from clinical samples. We further demonstrated the significantly synergistic effect of curcumin on IR-elicited cell apoptosis in ESCC both in vitro and in vivo. Our data suggested the potential therapeutic values of curcumin for future clinical investigations.