Cytotoxic Effect of Caffeic Acid Loaded in Chitosan-Grafted Carbon Nanotubes on MDA-MB-231 Breast Cancer Cell Lines

Breast cancer (BC) is the most common cancer leading to death depending on the stage of cancer. Targeting and drug delivery is an important strategy for cancer therapy such as BC. Destroying cancer cells and minimal damage to normal cells using nanotechnology strategy, especially carbon nanotube (CNT), is a key element in this area. Caffeic acid belongs to the polyphenol compound with anti-tumor activity. In this study, the viability of the MDA-MB-231 cell line was determined after exposing to the caffeic acid (100 µg/ml), oxidant carbon nanotube (OCNT)/caffeic acid (80 µg/ml), and chitosan (CS)/OCNT/caffeic acid (30 µg/ml) at 24 h post-exposure using 2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. The levels of gene and protein expression of Bax and Bcl-2 were investigated using real-time PCR and Western blotting, respectively. The apoptotic effect of caffeic acid, OCNT/caffeic acid, and CS/OCNT/caffeic acid on MDA-MB-231 was examined by flow cytometry using annexin VI. The data obtained represented that CS/OCNT/caffeic acid, OCNT/caffeic acid, and caffeic acid inhibited cell proliferation. Both mRNA and protein expression levels of Bax and Bcl-2 were up- and down-regulated compared with the control cells. However, the most effect belonged to the CS/OCNT/caffeic acid. The flow cytometry data represented that CS/OCNT/caffeic acid is very effective against MDA-MB-231. Based on the results, the CS/OCNT/caffeic acid showed the highest apoptotic effect on the MDA-MB-231 compared with the OCNT/caffeic acid and caffeic acid. The CS/OCNT/caffeic acid, OCNT/caffeic acid, and caffeic acid have toxicity for MDA-MB-231 cells through an apoptotic pathway by up-regulation of Bax expression level and down-regulation of Bcl-2.