KDM2B overexpression correlates with poor prognosis and regulates glioma cell growth

Abstract

Background: Gliomas are one of the most lethal cancers in the human central nervous system. Despite clinical treatment advancements, the prognosis of patients with glioma remains poor. KDM2B is a histone lysine demethylase, which has been observed in multiple tumors. But the concrete role of KDM2B in gliomas remains to be further illustrated.

Methods: The KDM2B expression in gliomas was detected with immunohistochemistry and Western blot assay. Furthermore, knockdown of KDM2B in U87 and U251 glioma cell lines, the proliferation capacity was evaluated by cell viability assay, colon formation assay and flow cytometry in vitro. Western blot assay was used to analyze the p21, EZH2 and cyclinD1 changes followed by knockdown of KDM2B.

Results: KDM2B was upregulated in tissues of glioma patients, and the expression was correlated to cancer progression. Downregulation of KDM2B in U87 and U251 glioma cell lines inhibited cell proliferation and arrested cell cycle in G0/G1 phase. In addition, silencing KDM2B promoted the upregulation of p21 while reduced the expression of EZH2 and cyclinD1.

Conclusion: Taken together, our results revealed that KDM2B might influence gliomas growth and act as a novel therapeutic target for glioma patients.

Keywords: EZH2; KDM2B; P21; glioma.

Figure 1

KDM2B expression in glioma tissues and normal brain tissues. Notes: (A) KDM2B expression was detected by immunohistochemistry, and KDM2B was stained in the nucleus and cytoplasm of the glioma cells. (B) KDM2B protein levels were determined by Western blot analysis. Each lane represents different samples. (C) The KDM2B protein data are presented in a scatter diagram. *P<0.05, **P<0.01. Abbreviation: WHO, World Health Organization.

Figure 2

Kaplan–Meier survival analysis of glioma patients. Note: There was a significant difference between the survival times of patients with high KDM2B expression and those with low KDM2B expression (P<0.05).

Figure 3

KDM2B knockdown in the GBM cell lines reduced cellular proliferation and induced G1/G0 cell cycle arrest. Notes: (A) The protein expression of KDM2B was detected after shKDM2B transfection. (B) Following shKDM2B stable transfection in the U87 and U251 cell lines, the viability of the cells was examined using an MTT assay. Knockdown of KDM2B reduced the viability of the U87 and U251 cells; **P<0.01. (C) The colony-forming assay showed that KDM2B knockdown inhibited cell growth in the U87 and U251 cells; **P<0.01. (D) KDM2B knockdown induced cell cycle arrest in the G0/G1 phase; *P<0.05. (E) Western blot assay evaluated the expression of the cyclin D1 proteins in U87 and U251 cell lines. (F) The protein levels of EZH2 and P21 were measured by Western blot analysis. Abbreviations: GBM, glioblastoma; OD, optical density.

Figure 3

KDM2B knockdown in the GBM cell lines reduced cellular proliferation and induced G1/G0 cell cycle arrest. Notes: (A) The protein expression of KDM2B was detected after shKDM2B transfection. (B) Following shKDM2B stable transfection in the U87 and U251 cell lines, the viability of the cells was examined using an MTT assay. Knockdown of KDM2B reduced the viability of the U87 and U251 cells; **P<0.01. (C) The colony-forming assay showed that KDM2B knockdown inhibited cell growth in the U87 and U251 cells; **P<0.01. (D) KDM2B knockdown induced cell cycle arrest in the G0/G1 phase; *P<0.05. (E) Western blot assay evaluated the expression of the cyclin D1 proteins in U87 and U251 cell lines. (F) The protein levels of EZH2 and P21 were measured by Western blot analysis. Abbreviations: GBM, glioblastoma; OD, optical density.