The alpha1-adrenergic receptor antagonist doxazosin inhibits EGFR and NF-kappaB signalling to induce breast cancer cell apoptosis.

The selective alpha(1)-adrenergic receptor antagonist doxazosin (dox) has been reported to inhibit prostate cancer proliferation. We now demonstrate that dox-treatment inhibits proliferation and induces apoptosis in breast cancer cells in vitro by mechanisms that do not wholly involve the alpha1-adrenergic receptor. Intriguingly, dox-treatment reduced phosphorylated EGFR expression, decreased pERK1/2 levels and decreased NF-kappaB, AP-1, SRE, E2F and CRE-mediated transcriptional activity.

Alpha1-adrenergic receptor antagonists: novel therapy for pituitary adenomas.

Pituitary tumors are common and cause considerable morbidity due to local invasion and altered hormone secretion. Doxazosin (dox), a selective alpha(1)-adrenergic receptor antagonist, used to treat hypertension, also inhibits prostate cancer cell proliferation. We examined the effects of dox on murine and human pituitary tumor cell proliferation in vitro and in vivo.