Table of Contents
Chemotherapy Research and Practice
Volume 2013 (2013), Article ID 593020, 16 pages
http://dx.doi.org/10.1155/2013/593020
Research Article

Inhibition of NF-κB by Dehydroxymethylepoxyquinomicin Suppresses Invasion and Synergistically Potentiates Temozolomide and γ-Radiation Cytotoxicity in Glioblastoma Cells

1Department of Pediatrics, Faculty of Medicine of Ribeirão Preto, University of São Paulo, Brazil
2Laboratório de Pediatria, Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto (USP), Bloco G, Avenida Bandeirantes, 3900 Bairro Monte Alegre, 14048-900 Ribeirão Preto, SP, Brazil
3Department of Genetics, Faculty of Medicine of Ribeirão Preto, University of São Paulo, Brazil
4Department of Surgery, Faculty of Medicine of Ribeirão Preto, University of São Paulo, Brazil
5Department of Clinics, Faculty of Medicine of Ribeirão Preto, University of São Paulo, Brazil
6Department of Applied Chemistry, Faculty of Science and Techonology, Keio University, Kanagawa 223-8522, Japan

Received 29 August 2012; Revised 16 December 2012; Accepted 2 January 2013

Academic Editor: G. J. Peters

Copyright © 2013 M. S. Brassesco et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Despite advances in neurosurgery and aggressive treatment with temozolomide (TMZ) and radiation, the overall survival of patients with glioblastoma (GBM) remains poor. Vast evidence has indicated that the nuclear factor NF-κB is constitutively activated in cancer cells, playing key roles in growth and survival. Recently, Dehydroxymethylepoxyquinomicin (DHMEQ) has shown to be a selective NF-κB inhibitor with antiproliferative properties in GBM. In the present study, the ability of DHMEQ to surmount tumor's invasive nature and therapy resistance were further explored. Corroborating results showed that DHMEQ impaired cell growth in dose- and time-dependent manners with G2/M arrest when compared with control. Clonogenicity was also significantly diminished with increased apoptosis, though necrotic cell death was also observed at comparable levels. Notably, migration and invasion were inhibited accordingly with lowered expression of invasion-related genes. Moreover, concurrent combination with TMZ synergistically inhibited cell growth in all cell lines, as determined by proliferation and caspase-3 activation assays, though in those that express O6-methylguanine-DNA methyltransferase, the synergistic effects were schedule dependent. Pretreatment with DHMEQ equally sensitized cells to ionizing radiation. Taken together, our results strengthen the potential usefulness of DHMEQ in future therapeutic strategies for tumors that do not respond to conventional approaches.