Connective tissue growth factor as an unfavorable prognostic marker promotes the proliferation, migration, and invasion of gliomas.

Abstract

BackgroundIn consideration of the difficulty in diagnosing high heterogeneous glioma, valuable prognostic markers are urgent to be investigated. This study aimed to verify that connective tissue growth factor (CTGF) is associated with the clinical prognosis of glioma, also to analyze the effect of CTGF on the biological function.MethodsIn this study, glioma and non-tumor tissue samples were obtained in 2012 to 2014 from the Department of Neurosurgery of Nanfang Hospital of Southern Medical University, Guangzhou, China. Based on messenger RNA (mRNA) data from the Cancer Genome Atlas (TCGA) and CCGA dataset, combined with related clinical information, we detected the expression of CTGF mRNA in glioma and assessed its effect on the prognosis of glioma patients. High expression of CTGF mRNA and protein in glioma were verified by reverse transcription-polymerase chain reaction, immunohistochemistry, and Western blotting. The role of CTGF in the proliferation, migration, and invasion of gliomas were respectively identified by methylthiazoletetrazolium assay, Transwell and Boyden assay in vitro. The effect on glioma cell circle was assessed by flow cytometry. For higher expression of CTGF in glioblastoma (GBM), the biological function of CTGF in GBM was investigated by gene ontology (GO) analysis.ResultsIn depth analysis of TCGA data revealed that CTGF mRNA was highly expressed in glioma (GBM, n = 163; lowly proliferative glioma [LGG], n = 518; non-tumor brain tissue, n = 207; LGG, t = 2.410, GBM, t = 2.364, P < 0.05). CTGF mRNA and protein expression in glioma (86%) was significantly higher than that in non-tumor tissues (18%) verified by collected samples. Glioma patients with higher expression of CTGF showed an obviously poorer overall survival (35.4 and 27.0 months compared to 63.3 and 55.1 months in TCGA and Chinese Glioma Genome Atlas (CGGA) databases separately, CGGA: χ2 = 7.596, P = 0.0059; TCGA: χ2 = 10.46, P = 0.0012). Inhibiting CTGF expression could significantly suppress the proliferation, migration, and invasion of gliomas. CTGF higher expression had been observed in GBM, and GO analysis demonstrated that the function of CTGF in GBM was mainly associated with metabolism and energy pathways (P < 0.001).ConclusionsCTGF is highly expressed in glioma, especially GBM, as an unfavorable and independent prognostic marker for glioma patients and facilitates the progress of glioma.