Synergistic effect of a combination of nanoparticulate Fe3O4 and gambogic acid on phosphatidylinositol 3-kinase/Akt/Bad pathway of LOVO cells
Lianghua Fang,1,3 Baoan Chen,2 Shenlin Liu,3 Ruiping Wang,3 Shouyou Hu,3 Guohua Xia,2 Yongli Tian,3 Xiaohui Cai2
1No 1 Clinical Medical College of Nanjing University of Chinese Medicine, 2Department of Hematology, Zhongda Hospital, Medical School, Southeast University, 3Department of Oncology, Jiangsu Province Hospital of Traditional Chinese Medicine, Nanjing, People's Republic of China
Background: The present study evaluated whether magnetic nanoparticles containing Fe3O4 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 Fe3O4. The typical morphological features of apoptosis in LOVO cells were observed after treatment comprising gambogic acid with and without magnetic nanoparticles containing Fe3O4. Transcription of cytochrome c, caspase 9, and caspase 3 genes was higher in the group treated with magnetic nanoparticles containing Fe3O4 and gambogic acid than in the groups that received gambogic acid or magnetic nanoparticles containing Fe3O4, 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 Fe3O4 was higher than in the groups receiving magnetic nanoparticles containing Fe3O4 or gambogic acid, while expression of p-PI3K, p-Akt, p-Bad, pro-caspase 9, and pro-caspase 3 degraded.
Conclusion: Magnetic nanoparticles containing Fe3O4 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.
Keywords: Fe3O4, magnetic nanoparticles, gambogic acid, LOVO cells, apoptosis, PI3K, Akt, Bad, pathway