This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Park, C.-M. Articles by Hong, S.-I. Search for Related Content PubMed PubMed Citation Articles by Park, C.-M. Articles by Hong, S.-I.

Ionizing Radiation Enhances Matrix Metalloproteinase-2 Secretion and Invasion of Glioma Cells through Src/Epidermal Growth Factor Receptor–Mediated p38/Akt and Phosphatidylinositol 3-Kinase/Akt Signaling Pathways

¹ Laboratory of Functional Genomics, ² Department of Neurosurgery, and ³ Laboratory Medicine and Clinical Pathology, Korea Institute of Radiological and Medical Sciences, Seoul, Korea and ⁴ Research Institute and Hospital, National Cancer Center, Goyang, Gyeonggi, Korea

Requests for reprints: Seok-Il Hong, Laboratory of Functional Genomics, Laboratory Medicine and Clinical Pathology, Korea Institute of Radiological and Medical Sciences, 215-4, Gongneung-Dong, Nowon-Ku, Seoul 139-706, Korea. Phone: 82-2-970-1260; Fax: 82-2-978-2005; E-mail: hongsicp{at}kcch.re.kr.

Glioblastoma is a severe type of primary brain tumor, and its highly invasive character is considered to be a major therapeutic obstacle. Several recent studies have reported that ionizing radiation (IR) enhances the invasion of tumor cells, but the mechanisms for this effect are not well understood. In this study, we investigated the possible signaling mechanisms involved in IR-induced invasion of glioma cells. IR increased the matrix metalloproteinase (MMP)-2 promoter activity, mRNA transcription, and protein secretion along with the invasiveness of glioma cells lacking functional PTEN (U87, U251, U373, and C6) but not those harboring wild-type (WT)-PTEN (LN18 and LN428). IR activated phosphatidylinositol 3-kinase (PI3K), Akt, and mammalian target of rapamycin, and blockade of these kinases by specific inhibitors (LY294002, Akt inhibitor IV, and rapamycin, respectively) and transfection of dominant-negative (DN) mutants (DN-p85 and DN-Akt) or WT-PTEN suppressed the IR-induced MMP-2 secretion in U251 and U373 cells. In addition, inhibitors of epidermal growth factor receptor (EGFR; AG490 and AG1478), Src (PP2), and p38 (SB203580), EGFR neutralizing antibody, and transfection of DN-Src and DN-p38 significantly blocked IR-induced Akt phosphorylation and MMP-2 secretion. IR-induced activation of EGFR was suppressed by PP2, whereas LY294002 and SB203580 did not affect the activations of p38 and PI3K, respectively. Finally, these kinase inhibitors significantly reduced the IR-induced invasiveness of these cells on Matrigel. Taken together, our findings suggest that IR induces Src-dependent EGFR activation, which triggers the p38/Akt and PI3K/Akt signaling pathways, leading to increased MMP-2 expression and heightened invasiveness of PTEN mutant glioma cells. (Cancer Res 2006; 66(17): 8511-9)

This article has been cited by other articles:

				Y.-K. I. Lau, L. B. Murray, S. S. Houshmandi, Y. Xu, D. H. Gutmann, and Q. Yu Merlin Is a Potent Inhibitor of Glioma Growth Cancer Res., July 15, 2008; 68(14): 5733 - 5742. [Abstract] [Full Text] [PDF]

				E. R. Smith, D. Zurakowski, A. Saad, R. M. Scott, and M. A. Moses Urinary Biomarkers Predict Brain Tumor Presence and Response to Therapy Clin. Cancer Res., April 15, 2008; 14(8): 2378 - 2386. [Abstract] [Full Text] [PDF]

				A. Yacoub, P. Gupta, M. A. Park, M. Rhamani, H. Hamed, D. Hanna, G. Zhang, D. Sarkar, I. V. Lebedeva, L. Emdad, et al. Regulation of GST-MDA-7 toxicity in human glioblastoma cells by ERBB1, ERK1/2, PI3K, and JNK1-3 pathway signaling Mol. Cancer Ther., February 1, 2008; 7(2): 314 - 329. [Abstract] [Full Text] [PDF]