Combined treatment of curcumin and small molecule inhibitors suppresses proliferation of A549 and H1299 human non-small-cell lung cancer cells.

Curcumin (diferuloylmethane) is a phenolic compound present in turmeric and is ingested daily in many parts of the world. Curcumin has been reported to cause inhibition on proliferation and induction of apoptosis in many human cancer cell lines, including non-small cell lung cancer cells (NSCLC). However, the clinical application of curcumin is restricted by its low bioavailability. In this report, it was observed that combined treatment of a low dosage of curcumin (5-10 µM) with a low concentration (0.1-2.5 µM) of small molecule inhibitors, including AG1478, AG1024, PD173074, LY294002 and caffeic acid phenethyl ester (CAPE) increased the growth inhibition in two human NSCLC cell lines: A549 and H1299 cells. The observation suggested that combined treatment of a low dosage of curcumin with inhibitors against epidermal growth factor receptor (EGFR), insulin-like growth factor 1 (IGF-1R), fibroblast growth factors receptor (FGFR), phosphatidylinositol 3-kinases (PI3K) or NF-κB signaling pathway may be a potential adjuvant therapy beneficial to NSCLC patients.