Human umbilical cord blood-derived mesenchymal stem cells inhibit C6 glioma via downregulation of cyclin D1.

AIMS AND BACKGROUND Glioma is difficult to treat and despite advances, outcomes remain poor and new treatment modalities are required. We studied the inhibitive effects of human umbilical cord blood-derived mesenchymal stem cells (UCB-MSCs) on glioma growth. MATERIAL AND METHODS UCB-MSCs were identified in mice by flow cytometric analysis, and neurogenic differentiation by immunohistochemistry. C6 cells were injected subcutaneously into the posterior right flank of each mouse. Dil-labeled UCB-MSCs were administrated by intravenous (IV) or intratumoral (IT) injection. Tumor blood vessel density was detected by counting the number of CD34-positive cells with endothelial morphology. Cyclin D1 protein expression was detected by immunohistochemistry and Western blot analysis. RESULTS A 26% reduction in overall tumor volume was observed after IV UCB-MSCs treatment, 36% in animals who received IT UCB-MSCs. UCB-MSC administration was associated with reduced neovascularization. We identified a 48% and 27% reduction in the number of cyclin D1-positive cells in mouse glioma tissues treated with UCB-MSCs IV and IT, respectively. CONCLUSION We demonstrated that UCB-MSCs potently inhibit glioma growth, reduce neovascularization, and decrease cyclin D1 protein expression in vivo. IV or IT UCB-MSC administration significantly inhibits glioma growth, and may represent a promising new therapy.