Inhibition of the JAK-2/STAT3 signaling pathway impedes the migratory and invasive potential of human glioblastoma cells
The objective of current treatment strategies for glioblastoma (GBM) is cytoreduction. Unfortunately, the deleterious migratory and invasive behavior of glial tumors remains largely unattended. The transcription factor signal transducer and activator of transcription (STAT) 3 is known to be involved in the development and progression of many different tumor types, including malignant gliomas. Beside other biological effects, STAT3 controls cell proliferation and tissue remodeling, processes common to both wound healing and tumor dissemination. Here, we report on impeded migratory and invasive potential of five different glioblastoma cell lines after treatment with AG490, a pharmacological inhibitor of the upstream STAT3 activator Janus kinase (JAK) 2. STAT3 was constitutively activated in all the cell lines tested, and treatment with AG490 eliminated the biologically active, tyrosine705-phosphorylated form of STAT3 in a dose-dependent fashion, as determined by Western blot analysis. Inhibition of activated STAT3 was paralleled by a decrease in transcriptional expression of the STAT3 target genes MMP-2 and MMP-9, and led to reduced proteolytic activity, as determined by zymography. Accordingly, the migratory behavior of all five GBM cell lines was impeded in monolayer wound-healing assays; invasive capacity in matrigel-coated trans-well assays was also hampered by treatment with AG490. The proliferative activity of the cell lines was also significantly reduced after treatment with AG490. The effects elicited by STAT3 inhibition were observed in both PTEN-expressing and PTEN-deficient cells. Because pharmacological inhibition of the JAK-2/STAT3 signaling pathway affects not only tumor cell proliferation but also the characteristic features of malignant gliomas, i.e. migration and invasion pertinent to invariable tumor recurrence and high morbidity, our findings support the idea that STAT3 is a suitable target in the treatment of brain tumors.
KeywordsGlioblastoma Migration Invasion STAT3
Proto-oncogene, small GTPase
Proto-oncogene, non-receptor tyrosine kinase
Sodium dodecyl sulfate
Polyacrylamide gel electrophoresis
Phosphatase and tensin homolog
Bovine serum albumin
The authors would like to thank C. Geist and H. Schweers, for excellent technical assistance, and M. Eberhardt, for assisting with the preparation of the figures. This work was financially supported by the Deutsche Forschungsgemeinschaft (DFG), grant # WE 4358/1-1 to JW and DK.
Conflicts of interest statement
The authors report no conflict of interest concerning the materials or methods used in this study or the findings reported in this paper.
- 1.Stupp R, Mason WP, van den Bent MJ, Weller M, Fisher B, Taphoorn MJ, Belanger K, Brandes AA, Marosi C, Bogdahn U, Curschmann J, Janzer RC, Ludwin SK, Gorlia T, Allgeier A, Lacombe D, Cairncross JG, Eisenhauer E, Mirimanoff RO (2005) Radiotherapy plus concomitant and adjuvant temozolomide for glioblastoma. N Engl J Med 352:987–996CrossRefPubMedGoogle Scholar
- 9.Loeffler S, Fayard B, Weis J, Weissenberger J (2005) Interleukin-6 induces transcriptional activation of vascular endothelial growth factor (VEGF) in astrocytes in vivo and regulates VEGF promoter activity in glioblastoma cells via direct interaction between STAT3 and Sp1. Int J Cancer 115:202–213CrossRefPubMedGoogle Scholar
- 12.Livak KJ, Schmittgen TD (2001) Analysis of relative gene expression data using real-time quantitative PCR and the 2(-Delta Delta C(T)) Method. Methods (San Diego, Calif) 25:402–408Google Scholar
- 13.Ponce ML (2001) In vitro matrigel angiogenesis assays. In: Murray JC (ed) Angiogenesis protocols. Humana Press, Totowa, NJ, pp 205–208Google Scholar
- 26.Carro MS, Lim WK, Alvarez MJ, Bollo RJ, Zhao X, Snyder EY, Sulman EP, Anne SL, Doetsch F, Colman H, Lasorella A, Aldape K, Califano A, Iavarone A (2010) The transcriptional network for mesenchymal transformation of brain tumours. Nature 463:318–325Google Scholar
- 30.Shariftabrizi A, Khorramizadeh MR, Saadat F, Alimoghadam K, Safavifar F, Ebrahimkhani MR (2005) Concomitant reduction of matrix metalloproteinase-2 secretion and intracellular reactive oxygen species following anti-sense inhibition of telomerase activity in PC-3 prostate carcinoma cells. Mol Cell Biochem 273:109–116CrossRefPubMedGoogle Scholar
- 31.Kargiotis O, Chetty C, Gondi CS, Tsung AJ, Dinh DH, Gujrati M, Lakka SS, Kyritsis AP, Rao JS (2008) Adenovirus-mediated transfer of siRNA against MMP-2 mRNA results in impaired invasion and tumor-induced angiogenesis, induces apoptosis in vitro and inhibits tumor growth in vivo in glioblastoma. Oncogene 27:4830–4840CrossRefPubMedGoogle Scholar
- 34.Birner P, Toumangelova-Uzeir K, Natchev S, Guentchev M (2010) STAT3 tyrosine phosphorylation influences survival in glioblastoma. J Neuro Oncol. doi: 10.1007/s11060-010-0195-8