Hyperthermia Induced by Magnetic Nanoparticles Improves the Effectiveness of the Anticancer Drug cis-Diamminedichloroplatinum

The cytotoxic enhancement of cisplatin by magnetic fluid hyperthermia (MFH) was investigated in human colon adenocarcinoma cells (Caco-2). A nanoparticle platform based on iron oxide functionalized with carboxymethyl dextran was employed to produce heat at the nanoscale. To assess the synergistic effect of hyperthermia and the anticancer drug cis-Diamminedichloroplatinum, commonly known as cisplatin (CIS), cell viability was measured 24, 48, and 72 hours after three different combined hyperthermia and CIS exposure sequences. These included CIS incubation prior to hyperthermia or magnetic fluid hyperthermia, CIS exposure only during hyperthermia or MFH, and additional CIS incubation following hyperthermia or MFH. Additional incubation of CIS after hyperthermia treatment appears to be more effective than prior CIS incubation for both hyperthermia treatments. Viability data also indicated that MFH combined with CIS is significantly more effective than hot water hyperthermia at the same temperature. A CIS concentration an order of magnitude lower than the calculated IC50 was found to be very effective in reducing cell viability. Such dramatic differences suggest that MFH may enhance the passive transport of CIS.