Research of Apoptosis Induction by the Application of Magnetic Nanoparticle of Fe₃O₄ Loaded with Daunorubicin and 5-Bromotetrandrine in K562/A02 Leukemic Cells

Objective: To observe the apoptosis of K562/A02 cells induced by application of Fe₃O₄-Magnetic Nanoparticle (Fe₃O₄-MNPs) loaded with Daunorubicin(DNR) and 5-Bromotetrandrine (BrTet) and to explore its possible molecular mechanism.

Methods: We detected the apoptosis of K562/A02 cells after treatment with Fe₃O₄-MNPs and BrTet with DNR alone or their combination by flow cytometry(FCM),Wright staining and DNA ladder. The expression of Bax and Bcl-2 protein was measured by Western blot.

Results: The result showed apoptotic characteristics after treated with this composite for 48 hours. Flow cytometry assay showed the percentage of apoptotic cells which were treated with Fe₃O₄-MNPs and BrTet with DNR alone or their combination for 48 hours increased from (7.9%±0.35)% to (15.5%±0.87)%, (19.7%±1.04)% and(40.8%±1.74)%, (P<0.05. After treated with this composite, the typical apoptotic morphological features appeared: condensation of cells and nuclear, disintegration of nuclear chromatin, and apoptotic body could be observed under microscope; DNA agarose gel electrophoresis showed ladder bands; the expression level of Bax protein increased (P < 0.01) and Bcl-2 protein decreased markedly (P < 0.01).

Conclusion: Our results suggest that Fe₃O₄-MNPs or BrTet with DNR induces apoptosis in K562/ADM cells, and when used together,they have distinct synergism. The up-regulation of Bax protein and the down-regulation of Bcl-2 protein may play important roles.