Synergistic effect of the combination of nanoparticulate Fe3O4 and Au with daunomycin on K562/A02 cells

Abstract

In this study, we have explored the possibility of the combination of the high reactivity of nano Fe3O4 or Au nanoparticles and daunomycin, one of the most important antitumor drugs in the treatment of acute leukemia clinically, to inhibit MDR of K562/A02 cells. Initially, to determine whether the magnetic nanoparticle Fe3O4 and Au can facilitate the anticancer drug to reverse the resistance of cancer cells, we have explored the cytotoxic effect of daunomycin (DNR) with and without the magnetic nano-Fe3O4 or nano-Au on K562 and K562/A02 cells by MTT assay. Besides, the intracellular DNR concentration and apoptosis of the K562/A02 cells was further investigated by flow cytometry and confocal fluorescence microscopic studies. The MDR1 gene expression of the K562/A02 cells was also studied by RT-PCR method. Our results indicate that 5.0 x 10(-7) M nano-Fe3O4 or 2.0 x 10(-8) M nano-Au is biocompatible and can apparently raise the intracellular DNR accumulation of the K562/A02 cells and increase the apoptosis of tumor cells. Moreover, our observations illustrate that although these two kinds of nanoparticles themselves could not lower the MDRI gene expression of the K562/A02 cells, yet they could degrade the MDR1 gene level when combining with anticancer drug DNR. This raises the possibility to combine the nano-Fe3O4 or nano-Au with DNR to reverse the drug resistance of K562/A02 cells, which could offer a new strategy for the promising efficient chemotherapy of the leukemia patients.

Figure 1

Effect of the different concentrations of daunomycin (DNR) on growth inhibitiom rates of K562/A02 cells (A) and K562 cells (B) by MTT assay.

Figure 2

Growth inhibiting rate of daunomycin (DNR) with or without nanoparticle treated-K562/A02 cells (48 h). Notes: P < 0.05, compared to DNR without nanoparticle treated-K562/A02 cells (single factor analysis of variance); ¹P < 0.01, compared with DNR without nanoparticle treated-K562/A02 cells (single factor analysis of variance).

Figure 3

Growth inhibiting rate of daunomycin (DNR) with or without nanoparticle treated-K562 cells (48 h). Notes: P < 0.05, compared with DNR without nanoparticle treated-K562 cells (single factor analysis of variance); ¹P < 0.01, compared with DNR without nanoparticle treated-K562 cells (single factor analysis of variance); ²P > 0.05, compared with DNR without nanoparticle treated-K562 cells (single factor analysis of variance).

Figure 4

The apoptosis of K562/A02 cells under daunomycin (DNR) with and without nanoparticles. K562/A02 cells (A–D) were incubated with Nano-Fe₃O₄ (5.0 × 10⁻⁷ M) (B), Nano-Au (2.0 × 10⁻⁸ M) (C), DNR (10 mg/L) (D) and nothing (A), respectively, and K562/A02 cells (E–F) were incubated with DNR (10 mg/L) in the presence of Nano-Fe₃O₄ (5.0 × 10⁻⁷ M) (E) or Nano-Au (2.0 × 10⁻⁸ M) (F) at 37 °C for 48 h.

Figure 5

Effect of nanoparticle on the intracellular accumulation of daunomycin (DNR) in K562/A02 cells (×1000). K562/A02 (A–C) and K562 (D–F) cells were incubated with DNR (50 mg/L) in the absence (A, D) or the presence of Nano-Fe₃O₄ (5.0×10⁻⁷ M) (B, E) or Nano-Au (2.0 × 10⁻⁸ M) (C, F) at 37 °C for 30 min. The cells were observed and photographed under a confocal fluorescent microscope.

Figure 6

The MDR1 mRNA level of K562/A02 cells with nanoparticles (5.0 × 10⁻⁷ M Nano-Fe₃O₄ or 2.0 × 10⁻⁸ M Nano-Au) in the absence or presence of DNR (10 mg/L) Lane:1, marker; 2, K562 (negative control); 3, K562/A02 (positive control); 4, Nano-Fe₃O₄; 5, Nano-Au; 6, DNR with Nano-Fe₃O₄; 7, DNR with Nano-Au.