ABSTRACT. Cytochalasin B (CB) is known to inhibit a number of cancer types, but its effects on gliomas are unknown. We examined the in vitro effects of CB on the proliferation of human glioma U251 cells, as well as determined its mechanism of action. Cell proliferation was determined using CCK-8. The effect of CB on U251 cell morphology was observed under a transmission electron microscope. Cell cycle distribution was assessed using propidium iodine and Giemsa staining, and cell apoptosis was determined by annexin V-fluorescein isothiocyanate/propidium iodide. Cell cycle-related proteins were determined by Western blot. CB effectively inhibited U251 cell proliferation in a dose-and time-dependent manner. The 24, 48, 72, and 96 h IC 50 values were 6.41 x 10 -2 , 9.76 x 10 -4 , 2.57 x 10 -5 , and 2.08 x 10 -5 M, respectively. CB increased the proportion of cells in the G2/M phase in a dose-dependent manner, thus increasing the mitotic index and decreasing cdc2 and cyclin B1 protein levels. CB M CB induced apoptosis in 23.4 ± 0.5% of U251 cells (P < 0.05 vs control group). Caspase-3, -8, and -9 activities were increased after CB treatment. CB inhibited U251 glioma cell proliferation by damaging the microfilament structure. CB also induced glioma cell apoptosis, suggesting that it may be an effective therapeutic agent against gliomas.

Objective:Craniopharyngiomas are rare, histologically benign but clinically challenging neoplasms. Here, we aimed to interrogate the effect and significance of Phosphatidylinositol-3-kinase (PI3K) signaling pathway on papillary craniopharyngioma (PCP) cell growth and survival.Methods: We used Western blotting (WB) experiments to evaluate the expression of the PI3K/protein kinase B (AKT) in Craniopharyngiomas tissues, relative to health tissues. Primary tumor cells were obtained from fresh PCP samples by cell culture and then determined by cell morphology, immunofluorescence staining and expression of specific cell markers. In this study, PCP cell lines, isolated from fresh PCP samples, were treated with different concentrations of LY294002, a PI3K/AKT signaling inhibitor, to evaluate their proliferation, migration and invasion. We determined the cell proliferation using Cell Counting Kit-8 and colony formation. We then used flow cytometry to evaluate cell apoptosis and cell cycle. In addition, cell migration and invasion levels were determined by wound healing and Transwell assays, respectively.Results: Our data demonstrated that the expression of phosphorylated-PI3K/AKT was upregulated in human craniopharyngioma tissues compared to the normal control tissues. Immunofluorescence assays showed the presence of cytokeratin (pan CK) and vimentin protein (VIM) in the PCP primary cells. Furthermore, inhibition of PI3K/AKT signaling blocks the proliferation, migration and invasion of the PCP primary cells.Conclusions:Taken together, our data robustly demonstrates that the PI3K/AKT signaling pathway mediates the proliferation, migration and invasion of the PCP cells.