Anticancer effect and feasibility study of hyperthermia treatment of pancreatic cancer using magnetic nanoparticles

We investigated the effect and feasibility of hyperthermia treatment on subcutaneous pancreatic cancer in female Kunming mice, using a murine pancreatic cancer cell line (MPC-83) established by us and found in this study to originate from epithelial pancreatic acinus. Magnetic fluid (MF) with ferromagnetic particles of about 20 nm in size was used as a heating mediator. MF was injected into the subcutaneous nodules with subaxillary regions of mice 10 days after tumor transplantation; homogeneous distribution of magnetic nanoparticles in nodules was easily detected by X-ray 24 h later. Mice were allocated to four groups as follows: no treatment (control); MF injection alone; alternating magnetic field (AMF) irradiation alone; and MF injection and hyperthermia generated by applying AMF (300 kHz, 110 Gs). The two hyperthermia-treated subgroup tumors reached central temperatures of 47 and 51˚C, respectively, for 30 min; while rectal temperature in both subgroups remained below 36˚C. Tumor growth was inhibited and survival significantly prolonged in the hyperthermia group compared with other groups (P<0.05). Tumor cells near the MF in the hyperthermia group apoptosed or necrosed immediately after hyperthermia. By day 14, there were no subcutaneous nodules; and residual magnetic nanoparticles were ingested by phagocytes. Nuclear proliferating cell nuclear antigen (PCNA) decreased in hyperthermia group tumor cells compared to the other groups; cytoplasmic heat shock protein 70 (HSP 70) was conspicuously higher immediately after hyperthermia (P<0.05). This technique had therapeutic potential and provided a new idea in the treatment of pancreatic cancer.