Roxatidine is a novel, specific, competitive H 2 -receptor antagonist that is used to treat gastric and duodenal ulcers, and which is known to suppress the growth of several tumors by reducing vascular endothelial growth factor (VEGF) expression. Nevertheless, it remains unclear whether roxatidine h
Gliotoxin enhances radiotherapy via inhibition of radiation-induced GADD45a, p38, and NFκB activation
✍ Scribed by Jung-Mu Hur; Hye-Jeong Yun; Soo-Hyung Yang; Woo-Yiel Lee; Min-ho Joe; Dongho Kim
- Publisher
- John Wiley and Sons
- Year
- 2008
- Tongue
- English
- Weight
- 273 KB
- Volume
- 104
- Category
- Article
- ISSN
- 0730-2312
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
The purpose of the study was to elucidate the mechanism underlying the enhancement of radiosensitivity to ^60^Co γ‐irradiation in human hepatoma cell line HepG2 pretreated with gliotoxin. Enhancement of radiotherapy by gliotoxin was investigated in vitro with human hepatoma HepG2 cell line. Apoptosis related proteins were evaluated by Western blotting. Annexin V/PI and reactive oxygen species (ROS) were quantified by Flow Cytometric (FACS) analysis. Gliotoxin (200 ng/ml) combined with radiation (4 Gy) treated cells induced apoptosis. Cells treated with gliotoxin (200 ng/ml) prior to irradiation at 4 Gy induced the expression of bax and nitric oxide (NO). The gliotoxin‐irradiated cells also increased caspase‐3 activation and ROS. Gadd45a, p38, and nuclear factor kappa B (NFκB) activated in irradiated cells was inhibited by Gliotoxin. Specific inhibitors of p38 kinase, SB203580, significantly inhibited NFκB activation and increased the cytotoxicity effect in cells exposed to gliotoxin combined with irradiation. However, SB203580 did not suppress the activation of Gadd45a in irradiated cells. Gliotoxin inhibited anti‐apoptotic signal pathway involving the activation of Gadd45a‐p38‐NFκB mediated survival pathway that prevent radiation‐induced cell death. Therefore, gliotoxin, blocking inflammation pathway and enhancing irradiation‐induced apoptosis, is a promising agent to increase the radiotherapy of tumor cells. J. Cell. Biochem. 104: 2174–2184, 2008. © 2008 Wiley‐Liss, Inc.
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