Potent therapeutic effect of hormonal cytostatic cortifen on intracranial brain tumors in rats was demonstrated. The effect was seen after single cortifen course in glioblastoma expressing glucocorticoid receptors and after two courses in glucocorticoid receptor-negative anaplastic astrocytoma. These findings confirmed the concept that selectivity of antitumor drugs can be improved when hormones are used as the carries of cytotoxic groups.
Key Words: cortifen; brain tumors; glucocorticoid receptors; antitumor effectCortifen (11-dehydroxy-17(z-hydroxy-21-[n-di-2(chlorethyl)aminophenyl acetate] corticosterone), a chlorophenacyl derivative of the natural mineralocorticoid 11-dehydroxy-17o~-hydroxycorticosterone, is now studied in phase II clinical trials. The drug acts via a dual mechanism: hormonal and alkylating. Cortifen specifically (Kd=]0 -9 M) binds to cytoplasmic glucocorticoid receptors (GR) in some cortifen-sensitive tumors in experimental animals and in breast, lung, kidney, and stomach cancers in humans [4]. Experimental studies demonstrated long-term antiproliferative effect of cortiten against a variety of cultured, induced, and spontaneous tumors of various histological origin in rats and mice. The prolonged antitumor effect can be explained by its penetration from the cytoplasm into nucleus in the term of a hormone-receptor complex and specific binding with high-affinity DNA sites resulting in DNA cross-linking in the target organs and tumors [2].The majority of human malignant brain tumors express GR. On the other hand, glucocorticoids are widely used tbr reducing brain edema. These two facts prompted us to study the effect of the new hormonal cytostatic cortifen on malignant brain tumors with different expression of GR in rats.