Complete regression of experimental prostate cancer in nude mice by repeated hyperthermia using magnetite cationic liposomes and a newly developed solenoid containing a ferrite core

BACKGROUND Magnetite cationic liposomes (MCLs) can be used to induce hyperthermia because they generate heat in an alternating magnetic field (AMF). This study aimed at developing more practical method for MCL hyperthermia examining the effect of MCL‐induced hyperthermia on human prostate cancer in vivo. MATERIALS AND METHODS A newly developed AMF generator incorporating a solenoid with a ferrite core (FC) was used. Human prostate cancer cells (PC‐3 and LNCap) were injected subcutaneously into nude mice. MCLs were injected into tumor nodule and the mice were exposed into AMF three times at 24‐hr intervals (repeated hyperthermia; RH) until complete tumor regression was observed. RESULTS Irradiation with an AMF generated by newly developed device can adequately increase the temperature of tumor tissue. Frequent RH resulted in complete tumor regression in all nude mice. CONCLUSION RH using MCLs may be a promising new therapy for hormone‐refractory human prostate cancer in the future. Prostate © 2006 Wiley‐Liss, Inc.