Degradation and remodelling of the extracellular matrix has been investigated, 
with the main focus on the balance between matrix metalloproteinases (MMP) and 
tissue inhibitor of metalloproteinases (TIMP). Recent reports disclose the 
presence of a novel MMP-inhibiting cell membrane-anchored glycoprotein 
designated 'reversion-inducing cysteine-rich protein with Kazal motifs' (RECK). 
Our main aim in this study was to elucidate the role of RECK in cell invasion of 
pituitary adenomas and its contribution to signal transduction. The function of 
RECK in cell invasion was investigated by comparing data obtained from 
full-length RECK clone transfection and gene silencing with RECK mRNA-targeting 
siRNA. RECK expression was confirmed using real-time RT-PCR and Western 
blotting. Levels of matrix metalloproteinases (MMP-2 and -9) and TIMP-1 were 
measured by zymography and reverse zymography, respectively. Cell invasion was 
examined with a 3-D invasion assay. The signal cascade was investigated by cDNA 
microarray analysis. As expected, expression of RECK was elevated upon cDNA 
transfection, and diminished using siRNA. We observed elevation of MMP-2 and -9 
expression and consequent 3-D cell invasion in cells under-expressing RECK. 
However, TIMP expression was not affected by RECK. Analysis with cDNA microarray 
revealed that RECK additionally upregulates growth hormone-releasing hormone 
receptor (GHRHR) and latrophilin 2 at the transcriptional level. Our findings 
collectively suggest that RECK regulates the cell signalling pathway, playing a 
critical neuroendocrinological role in the pituitary adenoma cell line.