A microarray study to characterize the molecular mechanism of TIMP-3-mediated tumor rejection

Glial cell invasion is a multistep cellular process that involves a complex system of tightly regulated proteases (matrix metalloproteinases; MMPs) and their endogenous inhibitors (tissue inhibitors of metalloproteinases; TIMPs) to mediate the degradation of the basement membrane and extracellular matrix. Tissue inhibitor of metalloproteinases-3 (TIMP-3) is a matrix-bound inhibitor of MMPs. In the present study, we have overexpressed the TIMP3 gene in human glioma cells with a herpes simplex virus type 1 amplicon-based vector. Oligonucleotide DNA arrays were employed to identify genes that were differentially modulated by the overexpression of TIMP-3. Consistent with the function of TIMP-3, genes associated with angiogenesis, growth factors, cytokines, death receptors, and substrates of the various MMPs were found to be up-regulated. Furthermore, caspases are important in the signaling pathway of cellular apoptosis, and the overexpression of TIMP-3 in glioma cells is tightly associated with the activation of caspases, including caspase-1, at both the mRNA level (P=0.0371) and the protein level. Moreover, the activation of an apoptotic pathway via the overexpression of TIMP-3 induced apoptosis of transduced human glioma cells in vitro and the growth inhibition of human glioma tumor xenografts in immunodeficient mice.