Magnetic nanoparticle-mediated hyperthermia therapy induces tumour growth inhibition by apoptosis and Hsp90/AKT modulation

Abstract

Purpose: We have evaluated the hyperthermia efficacy of oleic acid-functionalised Fe₃O₄ magnetic nanoparticles (MN-OA) under in vivo conditions and elucidated the underlying mechanism of tumour growth inhibition. Materials and methods: The efficacy and mechanism of tumour growth inhibition by MN-OA-mediated magnetic hyperthermia therapy (MHT) was evaluated in a murine fibrosarcoma tumour model (WEHI-164) using techniques such as TUNEL assay, Western blotting (WB), immunofluorescence (IF) staining and histopathological examination. In addition, bio-distribution of MN-OA in tumour/other target organs and its effect on normal organ function were studied by Prussian blue staining and serum biochemical analysis, respectively. Results: MN-OA-induced MHT resulted in significant inhibition of tumour growth as determined by measurement of tumour volume, as well as by in vivo imaging of tumour derived from luciferase-transfected WEHI-164 cells. Histopathology analysis showed presence of severe apoptosis and reduced tumour cells proliferation, which was further confirmed by TUNEL assay, reduced expression of Ki-67 and enhanced level of cleaved caspase-3, in tumours treated with MHT. Moreover, expression of heat stress marker, Hsp90 and its client protein, AKT/PKB was reduced by ∼50 and 80%, respectively, in tumours treated with MHT as studied by WB and IF staining. Serum analysis suggested insignificant toxicity of MN-OA (in terms of liver and kidney function), which was further correlated with minimal accumulation of MN-OA in target organs. Conclusions: These results suggest the involvement of apoptosis and Hsp90/AKT modulation in MN-OA-mediated MHT-induced tumour growth inhibition.

• Apoptotic death
• AKT/HSP90
• in vivo imaging
• magnetic hyperthermia therapy
• magnetic nanoparticles
• tumour growth inhibition

Acknowledgements

The authors acknowledge the help of Manjoor Ali, Radiation Biology & Health Sciences Division, BARC, Mumbai, India for microscopy, Milind Kamble and P. S. Dange for their assistance during biochemical analysis of serum samples, Hansa Yadav for technical support, and Asmita Sakpal, ACTREC, for technical assistance during transfection experiments.

Declaration of interest

This research work was funded by Bhabha Atomic Research Centre, Department of Atomic Energy, Government of India. The authors alone are responsible for the content and writing of the paper.

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