ABSTRACT
TMZ resistance remains one of the main reasons why treatment of glioblastoma (GBM) fails. In order to investigate the underlying proteins and pathways associated with TMZ resistance, we conducted a cytoplasmic proteome research of U87 cells treated with TMZ for 1 week, followed by differentially expressed proteins (DEPs) screening, KEGG pathway analysis, protein-protein interaction (PPI) network construction, and validation of key candidate proteins in TCGA dataset. A total of 161 DEPs including 65 upregulated proteins and 96 downregulated proteins were identified. Upregulated DEPs were mainly related to regulation in actin cytoskeleton, focal adhesion, and phagosome and PI3K-AKT signaling pathways which were consistent with our previous studies. Further, the most significant module consisted of 28 downregulated proteins that were filtered from the PPI network, and 9 proteins (DHX9, HNRNPR, RPL3, HNRNPA3, SF1, DDX5, EIF5B, BTF3, and RPL8) among them were identified as the key candidate proteins, which were significantly associated with prognosis of GBM patients and mainly involved in ribosome and spliceosome pathway. Taking the above into consideration, we firstly identified candidate proteins and pathways associated with TMZ resistance in GBM using proteomics and bioinformatic analysis, and these proteins could be potential biomarkers for prevention or prediction of TMZ resistance in the future.
Subject(s)
Brain Neoplasms/drug therapy , Brain Neoplasms/metabolism , Dacarbazine/analogs & derivatives , Drug Resistance, Neoplasm/drug effects , Glioblastoma/drug therapy , Glioblastoma/metabolism , Neoplasm Proteins/metabolism , Biomarkers, Tumor/metabolism , Cell Line, Tumor , Computational Biology/methods , Dacarbazine/pharmacology , Down-Regulation/drug effects , Gene Expression Regulation, Neoplastic/drug effects , Humans , Proteomics/methods , Ribosomal Protein L3 , Signal Transduction/drug effects , Temozolomide , Up-Regulation/drug effectsABSTRACT
So far, the prognostic value of matrix metalloproteinase 2 (MMP-2) and tissue inhibitor of matrix metalloproteinase 2 (TIMP-2) expressions in patients with gliomas has been widely reported, especially in China. But, the results were inconsistent. Thus, we conducted a meta-analysis to determine the correlation of MMP-2 and TIMP-2 expressions with the prognosis of patients with gliomas. Identical search strategies were used to search relevant literature in electronic databases updated to May 1, 2015, and odds ratios (ORs) with 95 % confidence intervals (95 % CIs) were estimated. Funnel plots and Egger's tests were conducted for the evaluation of publication bias, and heterogeneity and sensitivity were also analyzed. Finally, a total of 25 studies involving 1572 patients were included in the meta-analysis. Coincidentally, all these studies were conducted in Chinese population. It was found that MMP-2 expression was significantly associated with high-WHO grade gliomas (n = 24, OR = 6.54, CI = 4.98-8.60; I 2 = 0 %, P = 0.911) and poor overall survival (OS), while it did not correlate to age (n = 2, OR = 0.78, CI = 0.35-1.74; I 2 = 0 %, P = 0.621) and gender (n = 2, OR = 1.15, CI = 0.51-2.62; I 2 = 0 %, P = 0.995). Moreover, the results of the pooled analysis indicated that there was no association between TIMP-2 expression and the WHO grade of gliomas (n = 7, OR = 1.02, 95 % CI = 0.68-1.54; I 2 = 71.4 %, P = 0.002), but the ratio of MMP-2 and TIMP-2 (MMP-2/TIMP-2) rose with the increase of the WHO grade of gliomas. In conclusion, there was no correlation between TIMP-2 expression and the WHO grade of gliomas, while MMP-2 expression was potently associated with high-WHO grade of gliomas.
