Research

Hyperthermic treatment of DMBA-induced rat mammary cancer using magnetic nanoparticles

Jun Motoyama^1,2, Noriyuki Yamashita¹, Tomio Morino¹, Masashi Tanaka³, Takeshi Kobayashi³ and Hiroyuki Honda²

¹  Nanotherapy Co., Ltd, 19-11, Kikui 2-chome, Nishi-ku, Nagoya 451-0044, Japan

²  Department of Biotechnology, School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan

³  Department of Biological Chemistry, School of Bioscience and Biotechnology, Chubu University, 1200 Matsumoto-cho, Kasugai, Aichi 487-8501, Japan

BioMagnetic Research and Technology 2008, 6:2doi:10.1186/1477-044X-6-2

Published:	25 February 2008

Abstract

Background

We have developed magnetite cationic liposomes (MCLs) and applied them as a mediator of local hyperthermia. MCLs can generate heat under an alternating magnetic field (AMF). In this study, the in vivo effect of hyperthermia mediated by MCLs was examined using 7,12-dimethylbenz(a)anthracene (DMBA)-induced rat mammary cancer as a spontaneous cancer model.

Method

MCLs were injected into the mammary cancer and then subjected to an AMF.

Results

Four rats in 20 developed mammary tumors at more than 1 site in the body. The first-developed tumor in each of these 4 rats was selected and heated to over 43°C following administration of MCLs by an infusion pump. After a series of 3 hyperthermia treatments, treated tumors in 3 of the 4 rats were well controlled over a 30-day observation period. One of the 4 rats exhibited regrowth after 2 weeks. In this rat, there were 3 sites of tumor regrowth. Two of these regrowths were reduced in volume and regressed completely after 31 days, although the remaining one grew rapidly. These results indicated hyperthermia-induced immunological antitumor activity mediated by the MCLs.

Conclusion

Our results suggest that hyperthermic treatment using MCLs is effective in a spontaneous cancer model.