Abstract
To improve radiation therapy-induced quality of life impairments for prostate cancer patients, the development of radio-protectors is needed. Our previous work has demonstrated that MnTE-2-PyP significantly protects urogenital tissues from radiation-induced damage. So, in order for MnTE-2-PyP to be used clinically as a radio-protector, it is fully necessary to explore the effect of MnTE-2-PyP on human prostate cancer progression. MnTE-2-PyP inhibited prostate cancer growth in the presence and absence of radiation and also inhibited prostate cancer migration and invasion. MnTE-2-PyP altered p300 DNA binding, which resulted in the inhibition of HIF-1β and CREB signaling pathways. Accordingly, we also found that MnTE-2-PyP reduced the expression of three genes regulated by HIF-1β and/or CREB: TGF-β2, FGF-1 and PAI-1. Specifically, MnTE-2-PyP decreased p300 complex binding to a specific HRE motif within the PAI-1 gene promoter region, suppressed H3K9 acetylation, and consequently, repressed PAI-1 expression. Mechanistically, less p300 transcriptional complex binding is not due to the reduction of binding between p300 and HIF-1/CREB transcription factors, but through inhibiting the binding of HIF-1/CREB transcription factors to DNA. Our data provide an in depth mechanism by which MnTE-2-PyP reduces prostate cancer growth and metastasis, which validates the clinical use of MnTE-2-PyP as a radio-protector to enhance treatment outcomes in prostate cancer radiotherapy.