1. Academic Validation
  2. DMAPT inhibits NF-κB activity and increases sensitivity of prostate cancer cells to X-rays in vitro and in tumor xenografts in vivo

DMAPT inhibits NF-κB activity and increases sensitivity of prostate cancer cells to X-rays in vitro and in tumor xenografts in vivo

  • Free Radic Biol Med. 2017 Nov;112:318-326. doi: 10.1016/j.freeradbiomed.2017.08.001.
Marc S Mendonca 1 William T Turchan 2 Melanie E Alpuche 3 Christopher N Watson 4 Neil C Estabrook 3 Helen Chin-Sinex 3 Jeremy B Shapiro 3 Imade E Imasuen-Williams 3 Gabriel Rangel 3 David P Gilley 5 Nazmul Huda 6 Peter A Crooks 7 Ronald H Shapiro 4
Affiliations

Affiliations

  • 1 Departments of Radiation Oncology, Indiana University School of Medicine, Indianapolis, IN 46202 USA; Medical & Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202 USA. Electronic address: mmendonc@iupui.edu.
  • 2 Departments of Radiation Oncology, Indiana University School of Medicine, Indianapolis, IN 46202 USA; Medical & Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202 USA.
  • 3 Departments of Radiation Oncology, Indiana University School of Medicine, Indianapolis, IN 46202 USA.
  • 4 Departments of Radiation Oncology, Indiana University School of Medicine, Indianapolis, IN 46202 USA; Richard L. Roudebush, VA Medical Center, Indianapolis, IN 46202 USA.
  • 5 Department of Chemistry and Applied Sciences, South Dakota School of Mines and Technology, Rapid City, SD 57701 USA.
  • 6 Medical & Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202 USA.
  • 7 College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
Abstract

Constitutive activation of the pro-survival transcription factor NF-κB has been associated with resistance to both chemotherapy and radiation therapy in many human cancers, including prostate Cancer. Our lab and Others have demonstrated that the natural product parthenolide can inhibit NF-κB activity and sensitize PC-3 prostate cancers cells to X-rays in vitro; however, parthenolide has poor bioavailability in vivo and therefore has little clinical utility in this regard. We show here that treatment of PC-3 and DU145 human prostate Cancer cells with dimethylaminoparthenolide (DMAPT), a parthenolide derivative with increased bioavailability, inhibits constitutive and radiation-induced NF-κB binding activity and slows prostate Cancer cell growth. We also show that DMAPT increases single and fractionated X-ray-induced killing of prostate Cancer cells through inhibition of DNA double strand break repair and also that DMAPT-induced radiosensitization is, at least partially, dependent upon the alteration of intracellular thiol reduction-oxidation chemistry. Finally, we demonstrate that the treatment of PC-3 prostate tumor xenografts with oral DMAPT in addition to radiation therapy significantly decreases tumor growth and results in significantly smaller tumor volumes compared to xenografts treated with either DMAPT or radiation therapy alone, suggesting that DMAPT might have a potential clinical role as a radiosensitizing agent in the treatment of prostate Cancer.

Keywords

Comet assay; DMAPT; DNA double-strand break repair; DU145; NF-κB; PC-3; Split-dose repair; X-rays.

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