Correlation of N-cadherin expression in high grade gliomas with tissue invasion

Cadherins are Ca2+-dependent cell adhesion molecules that play an important role in tissue construction and morphogenesis in multicellular organisms. Over the last few years, reports have emerged in the literature describing the involvement of cadherins in tumor invasion and metastasis. Cadherins typically demonstrate up and down-regulation according to the biological needs of the tissue. Additionally, up-regulation of N-cadherin is thought to be important for tumor formation in early stages of tumor development. We studied N-cadherin in surgical specimens of patients with primary glioblastoma by microarray analysis and found that N-cadherin mRNA expression is up-regulated compared to normal brain. To study the effects of N-cadherin expression on invasion and metastasis in vitro and in vivo, we overexpressed N-cadherin in the rat C6 glioma cell line which normally has low levels of N-cadherin. We found that up-regulation of N-cadherin resulted in a slight decreased adhesion to type IV collagen, fibronectin, and laminin, but statistically significant decreased adhesion to type I collagen. Furthermore, increased expression of N-cadherin correlated with a dramatic decrease in invasive behavior in extracellular matrix invasion assays. We then proceeded to study these cell lines in vivo in a rat intracranial glioma model, and found that N-cadherin expression inversely correlated with invasion into surrounding tissues, irregular margins, and extracranial invasion. In summary, these data collectively demonstrate that N-cadherin levels are important in the malignant behavior of gliomas, and may serve as a prognostic indicator for patients with high-grade gliomas.