Single minded 2-s (SIM2-s) gene is expressed in human GBM cells and involved in GBM invasion.

The human single-minded 2 (SIM2) gene is mapped within the Down syndrome critical region (DSCR) of chromosome 21 and its short splice variant SIM2-s is suggested to be a molecular target for cancer therapy. It has been shown that SIM2-s is expressed in colon, pancreatic and prostate tumors but not in their corresponding normal tissues. In present study, we found that SIM2-s was expressed in glioma tissues as well as in glioblastoma (GBM) cell lines but not in other brain tumors or normal cortex. The invasive potential of GBM cells was significantly decreased by RNA interference targeting SIM2-s, while the proliferation was not affected. Further investigation showed that the mRNA and protein levels of matrix metalloproteinase 2 (MMP-2) were downregulated in cells treated with SIM2-s siRNA, concomitance with the upregulation of tissue inhibitor of matrix metalloproteinase 2 (TIMP-2). Moreover, the enzymatic activity of MMP-2 was clearly decreased. Our results collectively suggested that SIM2-s expressed in gliomas selectively and played a role in GBM cells invasion, which may be partly associated with the expression of MMP-2 and TIMP-2.