Mechanism of curcumin analog MHMD-induced cell death in A549 lung cancer cells

To investigate the anticancer properties of a chemosynthetic curcumin analog, (1E,6E)-4-((furan-2-yl)methylene)-1,7-bis(4-hydroxy-3-methoxyphenyl)hepta-1,6-diene-3,5-dione (C26H22O7, abbreviated MHMD) in A549 cells.

Inverted microscope was used to observe the alteration on cytomorphology. MTT assay was used to detect cell viability. Acridine-orange staining was used to measure autophagy, and AnnexinV/PI staining and Hoechst/PI staining to measure apoptosis and necrosis.

MTT assays showed that at 12 h, 24 h, 48 h, MHMD reduced cell viability with an IC50 of 27.46 µM, 18.86 µM, and 11.23 µM, respectively. Typical characteristics were observed in concert with cell death, including treated-cells getting brighter, rounder, and becoming non-adherent gradually. Additionally, acridine-orange staining suggested that autophagy didn't involve in MHMD-induced cell death. However, apoptosis and necrosis played important roles in MHMD-induced cell death by Hoechst33342/PI staining. It showed apoptosis was the main cause at low concentrations (≤ 4 µM), while with the concentrations rising, necrosis was the leading role. AnnexinV/PI staining again indicated the occurrence of apoptosis at 4 µM. Furthermore, the caspases inhibitor z-VAD-fmk could prevent MHMD-induced cell death, which showed much higher cell viability than those only treated with MHMD (4 µM). Moreover, MTT assay also demonstrated that MHMD did possess a greater anti-proliferative ability than curcumin.

The curcumin analog MHMD is able to induce A549 cell death in a time and dose-dependent manner via apoptosis and necrosis. And MHMD could be a more effective drug than curcumin.