ABSTRACT
BACKGROUND: Recent studies indicated that some glycolytic enzymes are complicated, multifaceted proteins rather than simple components of the glycolytic pathway. FBP1 plays a vital role in glucose metabolism, but its role in gastric cancer tumorigenesis and metastasis has not been fully understood. METHODS: The prognostic value of FBP1 was first studied in The Cancer Genome Atlas (TCGA) database and validated in in-house database. The effect of FBP1 on cell proliferation and metastasis was examined in vitro. Nonparametric test and Log-rank test were used to evaluate the clinical significance of FBP1 expression. RESULTS: In the TCGA cohort, FBP1 mRNA level were shown to be predictive of overall survival in gastric cancer (P = 0.029). In the validation cohort, FBP1 expression were inversely correlated with advanced N stage (P = 0.021) and lymphovascular invasion (P = 0.011). Multivariate Cox regression analysis demonstrated that FBP1 was an independent predictor for both overall survival (P = 0.004) and disease free survival (P<0.001). Functional studies demonstrated that ectopic FBP1 expression inhibited proliferation and invasion in gastric cancer cells, while silencing FBP1 expression had opposite effects (P<0.05). Mechanically, FBP1 serves as a tumor suppressor by inhibiting epithelial-mesenchymal transition (EMT). CONCLUSIONS: Downregulation of FBP1 promotes gastric cancer metastasis by facilitating EMT and acts as a potential prognostic factor and therapeutic target in gastric cancer.
Subject(s)
DNA Helicases/metabolism , DNA-Binding Proteins/metabolism , Epithelial-Mesenchymal Transition/physiology , Neoplasm Invasiveness/pathology , Stomach Neoplasms/metabolism , Stomach Neoplasms/pathology , Adult , Aged , Aged, 80 and over , Blotting, Western , Cell Line, Tumor , Cell Movement/genetics , Cell Movement/physiology , DNA Helicases/genetics , DNA-Binding Proteins/genetics , Epithelial-Mesenchymal Transition/genetics , Female , Humans , Male , Middle Aged , Neoplasm Invasiveness/genetics , Prognosis , RNA-Binding Proteins , Stomach Neoplasms/geneticsABSTRACT
DNA methylation plays a critical role during the development of acquired chemoresistance. The aim of this study was to identify candidate DNA methylation drivers of cisplatin (DDP) resistance in non-small cell lung cancer (NSCLC). The A549/DDP cell line was established by continuous exposure of A549 cells to increasing concentrations of DDP. Gene expression and methylation profiling were determined by high-throughput microarrays. Relationship of methylation status and DDP response was validated in primary tumor cell culture and the Cancer Genome Atlas (TCGA) samples. Cell proliferation, apoptosis, cell cycle, and response to DDP were determined in vitro and in vivo. A total of 372 genes showed hypermethylation and downregulation in A549/DDP cells, and these genes were involved in most fundamental biological processes. Ten candidate genes (S100P, GDA, WISP2, LOXL1, TIMP4, ICAM1, CLMP, HSP8, GAS1, BMP2) were selected, and exhibited varying degrees of association with DDP resistance. Low dose combination of 5-aza-2'-deoxycytidine (5-Aza-dC) and trichostatin A (TSA) reversed drug resistance of A549/DDP cells in vitro and in vivo, along with demethylation and restoration of expression of candidate genes (GAS1, TIMP4, ICAM1 and WISP2). Forced expression of GAS1 in A549/DDP cells by gene transfection contributed to increased sensitivity to DDP, proliferation inhibition, cell cycle arrest, apoptosis enhancement, and in vivo growth retardation. Together, our study demonstrated that a panel of candidate genes downregulated by DNA methylation induced DDP resistance in NSCLC, and showed that epigenetic therapy resensitized cells to DDP.
Subject(s)
Antineoplastic Agents/pharmacology , Carcinoma, Non-Small-Cell Lung/genetics , Cisplatin/pharmacology , DNA Methylation , Drug Resistance, Neoplasm/drug effects , Lung Neoplasms/genetics , RNA, Messenger/metabolism , Antimetabolites, Antineoplastic/pharmacology , Apoptosis , Azacitidine/analogs & derivatives , Azacitidine/pharmacology , Carcinoma, Non-Small-Cell Lung/pathology , Cell Cycle Checkpoints , Cell Cycle Proteins/metabolism , Cell Line, Tumor , Cell Proliferation , Decitabine , Epigenesis, Genetic , GPI-Linked Proteins/metabolism , Gene Expression Profiling/methods , Histone Deacetylase Inhibitors/pharmacology , Humans , Hydroxamic Acids/pharmacology , Lung Neoplasms/pathologyABSTRACT
AIM: 1) To evaluate the effect of prostaglandin E2 (PGE2) on the regulation of vascular endothelial growth factor (VEGF) expression in gastric MKN28 cells, and 2) to investigate the role of the epidermal growth factor receptor (EGFR) signal transduction pathway in any effect exerted by PGE2 on VEGF expression. METHODS: MKN28 cells were incubated with the vehicle (control) or with PGE2 in the presence or absence of AG1478, a selective inhibitor of EGFR tyrosine kinase, or PD098059, a selective inhibitor of the kinase responsible for ERK2 phosphorylation (mitogen-activated protein (MAP)/extracellular signal-regulated kinase (ERK)). Real-time quantitative polymerase chain reaction and Western blot analysis were used to evaluate VEGF mRNA and protein expression. The activity of EGFR and ERK2 was measured by Western blot analysis. RESULTS: PGE2 significantly up-regulated VEGF mRNA and protein expression and increased the activation of EGFR and ERK2. Incubation of MKN28 cells with AG1478 significantly reduced PGE2-induced EGFR activity, ERK2 activity, and VEGF mRNA and protein expression. Meanwhile, incubation of MKN28 with PD098059 reduced PGE2-induced ERK2 activity and VEGF mRNA and protein expression, but had no effect on EGFR activity. CONCLUSION: Our data suggested that PGE2 up-regulates VEGF expression in gastric cancer cells via transactivation of EGFR-MAPK signaling pathways, which may be mechanisms underlying the contribution of COX-2 to tumor angiogenesis in gastric cancer.
