A Mechanism of Antitumor Immunity Induced by Hyperthermia

Abstract

Resent evidence is accumulating for the important role of heat shock proteins (HSPs), initiating immune responses for cancer. On the other hand, because expression of HSPs protects cells from heat-induced apoptosis, HSP expression has been considered to be a complicating factor in hyperthermia. If HSP expression induced by hyperthermia is involved in cancer immunity, novel cancer immunotherapy based on this novel concept can be developed. In such a strategy, a tumor-specific hyperthermia system would be highly advantageous, because, for conventional hyperthermia systems, it is difficult to induce necrotic cell death without damaging normal tissue because of the thermotolerance induced by HSPs. To achieve tumor-specific hyperthermia, an intracellular hyperthermia system using magnetite nanoparticles was developed. This novel hyperthermia system can induce necrotic cell death via HSP expression, which in turn induces antitumor immunity. In the present article, a mechanism of antitumor immunity caused by intracellular hyperthermia using magnetite nanoparticles is reviewed.