Novel antitumor agent and screening method for novel antitumor agent

摘要

Provided are: a novel anti-tumor agent; a method for screening for a novel anti-tumor agent; and a novel method for treating a malignant tumor. The novel anti-tumor agent comprises a substance capable of inhibiting isocitrate dehydrogenase 3 (IDH3) as an active ingredient. The method for screening for a novel anti-tumor agent employs the inhibition of the activity of IDH3 as a measure. The novel method for treating a malignant tumor comprises inhibiting at least one of IDH3-constituting subunits as a target factor. Attention is focused on a fact that the resistance to a cancer therapy is increased through the activation of hypoxia-inducible factor 1 (HIF-1), which is a factor occurring normally in a solid tumor, under low-oxygen environments, and a substance capable of controlling the activation of HIF-1 is searched for. As a result, it is newly found that IDH3 is involved in the activation of HIF-1. This finding leads to the accomplishment of the present invention.