Karyopherin β1 Regulates Proliferation Of Human Glioma Cells Via Wnt/β-catenin Pathway

Objective: To investigate the function of karyopherin β1(KPNB1) in the progress of glioma, we detected the expression of KPNB1 in 100 glioma specimens. Moreover we employed the glioma cell lines to demonstrate the regulation function of KPNB1 to Wnt/β-Catenin pathway and the influence to the proliferation of glioma.Methods: Applying the western blot Assay and immunohistochemistry, we detected the expression of KPNB1 and Ki-67 in 100 glioma specimens. Comprehension analysis of the clinical-pathological data showed us the relation of glioma WHO grades, proliferation and prognosis. Employing the serum-starve models with glioma cell lines, U251 and U87 MG, we detected the expression of KPNB1, β-Catenin and other cell proliferation makers, such as PCNA(proliferating cell nuclear antigen), p27. Then, we carried out the flow cytometry analysis of cell cycle, cell counting kit(CCK)-8 and colony formation assay to detect the cells treated with shRNAs(short hairpin RNA), to demonstrate the regulation of KPNB1 to cell proliferation. Moreover, we show the influence to the distribution of β-Catenin in cell cytoplasm and nucleus. Finally, with immunoprecipitation we identified the direct interaction between KPNB1 and β-Catenin.Results: In current study, we demonstrated for the first time that the role of KPNB1 in human glioma. KPNB1 was over-expressed as the well-known trend of Ki-67(p<0.01) and tightly closed to poor prognosis, as an independent prognostic factor. In vitro, up-regulation of KPNB1 was accompanied with certain elevated levels of proliferation markers, employing U251 and U87 MG cells as serum-starve models. Silencing KPNB1 in U251 and U87 MG led to G1 phase arrested directly via flow cytometry analysis. The decreasing expression of KPNB1 and β-catenin was detected in the nucleus of KPNB1-depletion cell models respectively, which indicated that KPNB1 functioned via β-catenin signal. And the interaction between KPNB1 and β-catenin was proved clearly by immunoprecipitation. Taken together, it showed that KPNB1 might accelerate human glioma proliferation via Wnt/β-Catenin Pathway.Conclusions: 1.There is great correlation between the over-expression of KPNB1 andthe WHO grades of human glioma. And the over-expression of KPNB1 is equal to poor prognosis of glioma patients.2. The regulation to cell proliferation is relied on the changes of Wnt/β-Catenin pathway because of the over-expression of KPNB1.3. There is direct interaction between KPNB1 and β-Catenin.