JAK/STAT 인산화 및 VEGFR-2/Akt/mTOR 신호전달 억제를 통한 독사조신의 난소암 억제 기전 규명

Abstract

Doxazosin, a commonly prescribed treatment for patients with benign prostatic hyperplasia, serves as an α1-blocker of the adrenergic receptors. In this study, we calculated its effect on the ovarian carcinoma cell system and animal model. Doxazosin induces dose-dependent growth and time-dependent suppression and is additively activated through IFN-α or IFN-γ stimulation. At the same time, they both enhanced G1 phase arrest, as well as the activity of caspase-3 and PARP, and the reduction of cyclin D1 and CDK4 protein levels. Doxazosin growth suppression was abolished either by the Janus family of tyrosine kinase (JAK) or the signal transducer and activator of transcription (STAT) inhibitor treatment. The activity of JAK/STAT was dependent on the level of doxazosin, suggesting a requirement of doxazosin for the activation of JAK/STAT. Furthermore, doxazosin plus IFN-α or doxazosin plus IFN-γ additively suppressed the activation of the JAK/STAT signals through phosphorylation of JAK and STAT, thus affecting the activation of subsequent downstream signaling components PI3K, mTOR, 70S6K and PKCδ. And in vivo study demonstrated that doxazosin significantly suppressed tumor growth in an ovarian xenograft model, inducing apoptotic cell death by up-regulating the expression of p53, whereas c-Myc expression was markedly reduced. Therefore, our data findings indicate that doxazosin can modulate the apoptotic effects of IFN-α and IFN-γ through the JAK/STAT signaling pathways. Collectively, we indicate that this action may be a potent chemotherapeutic property against ovarian carcinoma. Doxazosin also inhibited vascular endothelial growth factor (VEGF)-induced HUVEC migration as well as capillary-like structure tube formation in vitro. It also suppresses the expression of HIF-1α and VEGF in ovarian carcinoma cells. Doxazosin inhibited phosphorylation of vascular endothelial growth factor receptor-2 (VEGFR-2) and transcription of VEGFR-2. Doxazosin inhibited PI3K, Akt, PDK1 and mTOR phosphorylation but had no effect on ERK1/2 phosphorylation by VEGF treatment. Our results provide evidence for the cellular function in endothelial cell system that is relevant to angiogenesis through the inhibition of the Akt/mTOR phosphorylation by interacting with VEGFR-2. Furthermore, doxazosin prohibited VEGFR-2 phosphorylation and suppressed tumor vascularization in a xenograft model of human ovarian cancer. We found the biological function of doxazosin to be a potent anti-ovarian cancer agent by inhibition of JAK/STAT phosphorylation and anti-angiogenic agent by suppression of VEGFR-2 signaling pathway. Therefore, doxazosin combination therapies may be a more useful approach for more advanced ovarian cancers and recurrent patients