Synergistic effect of a combination of nanoparticulate Fe(3)O(4) and gambogic acid on phosphatidylinositol 3-kinase/Akt/Bad pathway of LOVO cells

BACKGROUND: The present study evaluated whether magnetic nanoparticles containing Fe(3)O(4) could enhance the activity of gambogic acid in human colon cancer cells, and explored the potential mechanisms involved. METHODS: Cytotoxicity was evaluated by MTT assay. The percentage of cells undergoing apoptosis was analyzed by flow cytometry, and cell morphology was observed under both an optical microscope and a fluorescence microscope. Reverse transcriptase polymerase chain reaction and Western blot assay were performed to determine the transcription of genes and expression of proteins, respectively. RESULTS: Gambogic acid could inhibit proliferation of LOVO cells in a dose-dependent and time-dependent manner and induce apoptosis, which was dramatically enhanced by magnetic nanoparticles containing Fe(3)O(4). The typical morphological features of apoptosis in LOVO cells were observed after treatment comprising gambogic acid with and without magnetic nanoparticles containing Fe(3)O(4). Transcription of cytochrome c, caspase 9, and caspase 3 genes was higher in the group treated with magnetic nanoparticles containing Fe(3)O(4) and gambogic acid than in the groups that received gambogic acid or magnetic nanoparticles containing Fe(3)O(4), but transcription of phosphatidylinositol 3-kinase, Akt, and Bad genes decreased. Notably, expression of cytochrome c, caspase 9, and caspase 3 proteins in the group treated with gambogic acid and magnetic nanoparticles containing Fe(3)O(4) was higher than in the groups receiving magnetic nanoparticles containing Fe(3)O(4) or gambogic acid, while expression of p-PI3K, p-Akt, p-Bad, pro-caspase 9, and pro-caspase 3 degraded. CONCLUSION: Magnetic nanoparticles containing Fe(3)O(4) can enhance apoptosis induced by gambogic acid which may be closely related to regulation of the PI3K/Akt/Bad pathway in the treatment of human colon cancer.