Induction of membrane-type-1 matrix metalloproteinase by epidermal growth factor-mediated signaling in gliomas.
Increased expression of membrane-type matrix metalloproteinases (MT-MMPs) has previously been reported to correlate with increasing grade of malignancy in gliomas, a relationship shared with alterations in epidermal growth factor receptor (EGFR) signaling. To investigate the possibility of a causative role for EGFR signaling in increasing MT-MMP expression and subsequent peritumoral proteolysis, we characterized glioma cell lines for expression of MT1-MMP, MT2-MMP, MT3-MMP, and MT5-MMP by Western blotting and by quantitative real-time polymerase chain reaction analysis, and for MMP-2 activity following epidermal growth factor (EGF) stimulation. EGF stimulation of glioma cell lines resulted in a 2- to 4-fold increase in MT1-MMP mRNA levels. Although there were slight differences in MT2-, MT3-, and MT5-MMP mRNA expression following EGF stimulation, none of these demonstrated an increase similar to that of MT1-MMP expression. Treatment of high-grade glioma cell lines U251MG and IPSB-18 with EGF for 24 h resulted in a several-fold increase in MT1-MMP protein (2.5- and 5.1-fold, respectively) and in cyclin D1 (2.9-fold), as compared to untreated controls. No significant increase was detected in other MT-MMPs at the protein level. Although there was no detectable increase in proMMP-2 protein, there was an increase in MMP-2 activity. Furthermore, the MT1-MMP induction by EGF was prevented by pretreatment with the EGFR-specific tyrphostin inhibitor AG1478. Similarly, treatment with the phosphatidylinositol 3-kinase inhibitor LY294002 prevented the induction of MT1-MMP protein by EGF stimulation. These compounds additionally inhibited EGF-stimulated invasion in Matrigel Transwell assays. Our results indicate that one mechanism of EGFR-mediated invasiveness in gliomas may involve the induction of MT1-MMP.
Department of Neurosurgery, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, VA 23298, USA.
Timothy E
TE
Van Meter
William C
WC
Broaddus
Harcharan K
HK
Rooprai
Geoffrey J
GJ
Pilkington
Helen L
HL
Fillmore
D045744:Cell Line, Tumor; D004305:Dose-Response Relationship, Drug; D004790:Enzyme Induction / Q000502:physiology; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D066246:ErbB Receptors / Q000096:biosynthesis* / Q000235:genetics; D005910:Glioma / Q000201:enzymology* / Q000235:genetics; D006801:Humans; D053517:Matrix Metalloproteinase 15; D053513:Matrix Metalloproteinase 16; D053504:Matrix Metalloproteinases, Membrane-Associated; D008666:Metalloendopeptidases / Q000096:biosynthesis* / Q000235:genetics; D015398:Signal Transduction / Q000502:physiology*
C507098:MMP15 protein, human; C507102:MMP16 protein, human; D004815:Epidermal Growth Factor; D066246:ErbB Receptors; D053517:Matrix Metalloproteinase 15; D053513:Matrix Metalloproteinase 16; D053504:Matrix Metalloproteinases, Membrane-Associated; D008666:Metalloendopeptidases