ABSTRACT
BACKGROUND: MicroRNAs (miRNAs) have demonstrated their potential as biomarkers for lung cancer diagnosis. In recent years, miRNAs have been found in body fluids such as serum, plasma, urine and saliva. Circulating miRNAs are highly stable and resistant to RNase activity along with, extreme pH and temperatures in serum and plasma. In this study, we investigated serum miRNA profiles that can be used as a diagnostic biomarker of non-small cell lung cancer (NSCLC). METHODS: We compared the expression profile of miRNAs in the plasma of patients diagnosed with lung cancer using an miRNA microarray. The data from this assay were validated by quantitative real-time PCR (qRT-PCR). RESULTS: Six miRNAs were overexpressed and three miRNAs were underexpressed in both tissue and serum from squamous cell carcinoma (SCC) patients. Sixteen miRNAs were overexpressed and twenty two miRNAs were underexpressed in both tissue and serum from adenocarcinoma (AC) patients. Of the four miRNAs chosen for qRT-PCR analysis, the expression of miR-23a was consistent with microarray results from AC patients. Receiver operating characteristic (ROC) curve analyses were done and revealed that the level of serum miR-23a was a potential marker for discriminating AC patients from chronic obstructive pulmonary disease (COPD) patients. CONCLUSION: Although a small number of patients were examined, the results from our study suggest that serum miR-23a can be used in the diagnosis of AC.
Subject(s)
Humans , Adenocarcinoma , Biomarkers , Body Fluids , Carcinoma, Non-Small-Cell Lung , Carcinoma, Squamous Cell , Gene Expression Profiling , Hydrogen-Ion Concentration , Lung , Lung Neoplasms , MicroRNAs , Plasma , Pulmonary Disease, Chronic Obstructive , Real-Time Polymerase Chain Reaction , Ribonucleases , ROC Curve , SalivaABSTRACT
Lysophosphatidic acid (LPA) is a bioactive phospholipids and involves in various cellular events, including tumor cell migration. In the present study, we investigated LPA receptor and its transactivation to EGFR for cyclooxygenase-2 (COX-2) expression and cell migration in CAOV-3 ovarian cancer cells. LPA induced COX-2 expression in a dose-dependent manner, and pretreatment of the cells with pharmacological inhibitors of Gi (pertussis toxin), Src (PP2), EGF receptor (EGFR) (AG1478), ERK (PD98059) significantly inhibited LPA- induced COX-2 expression. Consistent to these results, transfection of the cells with selective Src siRNA attenuated COX-2 expression by LPA. LPA stimulated CAOV-3 cell migration that was abrogated by pharmacological inhibitors and antibody of EP2. Higher expression of LPA2 mRNA was observed in CAOV-3 cells, and transfection of the cells with a selective LPA2 siRNA significantly inhibited LPA-induced activation of EGFR and ERK, as well as COX-2 expression. Importantly, LPA2 siRNA also blocked LPA-induced ovarian cancer cell migration. Collectively, our results clearly show the significance of LPA2 and Gi/Src pathway for LPA-induced COX-2 expression and cell migration that could be a promising drug target for ovarian cancer cell metastasis.
Subject(s)
Female , Humans , Butadienes/pharmacology , Cell Line, Tumor , Cell Movement/drug effects , Cyclooxygenase 2/biosynthesis , Extracellular Signal-Regulated MAP Kinases/antagonists & inhibitors , Flavonoids/pharmacology , GTP-Binding Protein alpha Subunits, Gi-Go/antagonists & inhibitors , Lysophospholipids/pharmacology , Nitriles/pharmacology , Ovarian Neoplasms/metabolism , Pertussis Toxin/pharmacology , Protein-Tyrosine Kinases/antagonists & inhibitors , Proto-Oncogene Proteins/antagonists & inhibitors , Pyrimidines/pharmacology , ErbB Receptors/antagonists & inhibitors , Receptors, Lysophosphatidic Acid/metabolism , Receptors, Prostaglandin E/metabolism , Signal Transduction , Transcriptional Activation , Tyrphostins/pharmacologyABSTRACT
Various cell types in higher multicellular organisms are genetically homogenous, but are functionally and morphologically heterogeneous due to the differential expression of genes during development, which appears to be controlled by epigenetic mechanisms. However, the exact molecular mechanisms that govern the tissue-specific gene expression are poorly understood. Here, we show that dynamic changes in histone modifications and DNA methylation in the upstream coding region of a gene containing the transcription initiation site determine the tissue-specific gene expression pattern. The tissue-specific expression of the transgene correlated with DNA demethylation at specific CpG sites as well as significant changes in histone modifications from a low ratio of methylated H3- lysine 4 or acetylated H3-lysine 9, 14 to acetylated H4 to higher ratios. Based on the programmed status of transgene silenced in cloned mammalian ear-derived fibroblasts, the transgene could be reprogrammed by change of histone modification and DNA methylation by inhibiting both histone deacetylase and DNA methylation, resulting in high expression of the transgene. These findings indicate that dynamic change of histone modification and DNA methylation is potentially important in the establishment and maintenance of tissue-specific gene expression.