The cellular labeling and pH-sensitive responsive-drug release of celastrol in cancer cells based on Cys-CdTe QDs

As one of the active compounds derived from Traditional Chinese Medicine, Celastrol (CSL) had cytotoxicity for human leukemia cancer cells K562 and its multidrug-resistant cell line K562/A02. Here, we introduced cysteamine-modified CdTe QDs as the labeling and drug carrier into CSL research and found that the self-assembly and conjugation of anticancer molecular CSL with the Cys-CdTe QDs could significantly increase the drug's cytotoxicity for K562 cells. More important, these CSL-Cys-CdTe nanocomposites could overcome the multidrug resistance of K562/A02 cells and efficiently inhibit the cancer cell proliferation by realizing the pH-sensitive responsive release of CSL to cancer cells. The enhanced cytotoxicity was caused by the increase of the G2/M phase arrest for K562/A02 cells as well as for K562 cells. Cys-CdTe QDs can readily bind on the cell plasma membranes and be internalized into cancer cells to trace and detect human leukemia cancer cells in real time. In addition, these Cys-CdTe QDs can facilitate the inhibition of the multidrug resistance of K562/A02 cells and readily induce apoptosis. As a good photosensitizer for the therapy, labeling, and tracing of cancer cells, the combination of CSL with Cys-CdTe QDs can optimize the use of and a new potential therapy method for CSL and yield new tools to explore the mechanisms of active compounds from Traditional Chinese Medicine.