Isolation of a Natural Inhibitor of Human Malignant Glial Cell Invasion: Inter α-Trypsin Inhibitor Heavy Chain 2

Abstract

Malignant central nervous system (CNS) tumors, such as glioblastoma multiforme, invade the brain and disrupt normal tissue architecture, making complete surgical removal virtually impossible. Here, we have developed and optimized a purification strategy to isolate and identify natural inhibitors of glioma cell invasion in a three-dimensional collagen type I matrix. Inter A-trypsin inhibitor heavy chain 2 (ITI H2) was identified from the most inhibitory fractions and its presence was confirmed both as a single protein and in a bikunin-bound form. Stable overexpression in U251 glioma cells validated ITI H2's strong inhibition of human glioma cell invasion together with significant inhibition of cell proliferation and promotion of cell-cell adhesion. Analysis of primary human brain tumors showed significantly higher levels of ITI H2 in normal brain and low-grade tumors compared with high-grade gliomas, indicating an inverse correlation with malignancy. The phosphatidylinositol 3-kinase/Akt signaling cascade seemed to be one of the pathways involved in the effect of ITI H2 on U251 cells. These findings suggest that reduction of ITI H2 expression correlates with brain tumor progression and that targeting factors responsible for its loss or restoring the ITI supply exogenously may serve as potential therapeutic strategies for a variety of CNS tumors. (Cancer Res 2006; 66(3): 1464-72)

Serum Inter-α-inhibitor Activates the Yes Tyrosine Kinase and YAP/TEAD Transcriptional Complex in Mouse Embryonic Stem Cells

“…However, a few studies have demonstrated different effects of HC1 and HC2. Tamra et al showed that HC2 acts as a natural inhibitor of brain tumor invasion, and that addition of conditioned medium from cells expressing HC2 or forced expression of HC2 in the glioma cell line inhibits invasion and proliferation in vitro by inhibiting the PI3K/Akt pathway (33). Another study by Sanggaard et al suggests that HC2 is necessary for the TSG-6-mediated transfer to take place, possibly explaining both the inability of HC1 alone to induce TEAD family and the need for higher concentrations of HC2 to induce a robust effect on TEAD activity (45).…”

“…Moreover, the released heavy chains have been shown to induce effects of their own, such as inhibiting the migration properties of a malignant glioma cell line in vitro (33,34). Therefore, purified HC1 and HC2 domains were independently assessed for their ability to activate TEAD family-dependent transcription.…”

Inhibition of medulloblastoma cell invasion by Slit

“…Cell culture C6 (murine astrocytoma) cells were cultured and seeded into spinner culture flasks as previously described Werbowetski-Ogilvie et al, 2006). All culture reagents were obtained from Gibco BRL (Invitrogen, Burlington, ON, Canada) unless otherwise stated.…”

Src Induces Podoplanin Expression to Promote Cell Migration

“…Many of these genes have been implicated in the regulation of tumor cell growth and migration. For example, recent experiments indicate that Epb4.1l3 (erythrocyte protein band 4.1-like 3) (19) and Itih2 (inter-␣-trypsin inhibitor heavy chain) (20) can suppress tumor cell invasion and metastasis. Induction of three of these genes, Vcam1, Sdpr, and Fhl1, has been previously associated with contact normalization (13).…”