ABSTRACT
OBJECTIVE: To clarify the function of miRNA-153-3p in gefitinib-sensitive non-small cell lung cancer (NSCLC) and the underlying mechanism. PATIENTS AND METHODS: The expressions of miRNA-153-3p, LC3B and ATG5 in gefitinib-resistant and gefitinib-sensitive NSCLC tissues were determined by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). The correlation between miRNA-153-3p to LC3B or ATG5 was analyzed. We evaluated autophagy level in gefitinib-resistant NSCLC cells by calculating the percentage of PC-9/GR and HCC827/GR cells with positive GFP-LC3, as well as determining autophagy-related gene levels. The potential binding between ATG5 and miRNA-153-3p were verified by Dual-Luciferase reporter gene assay. The regulatory effects of miRNA-153-3p/ATG5 on gefitinib-sensitivity and apoptosis were finally examined by cytotoxicity assay and Annexin V-fluorescein isothiocyanate (FITC)/Propidium Iodide (PI) staining, respectively. RESULTS: MiRNA-153-3p was lowly expressed in gefitinib-resistant NSCLC relative to the gefitinib-sensitive ones. MiRNA-153-3p was negatively correlated with autophagy activity marker LC3B in gefitinib-resistant NSCLC patients. Compared with parental cells, gefitinib-resistant NSCLC cell lines PC-9/GR and HCC827/GR presented a lower level of miRNA-153-3p and a higher level of autophagy. The overexpression of miRNA-153-3p greatly inhibited autophagy level. ATG5 could directly bind to miRNA-153-3p, and ATG5 was highly expressed in gefitinib-resistant NSCLC. The correlation analysis found a negative correlation between ATG5 and miRNA-153-3p and a positive correlation between ATG5 and LC3B in gefitinib-resistant NSCLC. More importantly, ATG5 reversed the regulatory effects of miRNA-153-3p on autophagy, gefitinib-sensitivity and apoptosis of PC-9/GR and HCC827/GR cells. CONCLUSIONS: MiRNA-153-3p is lowly expressed in gefitinib-resistant NSCLC patients. The overexpression of miRNA-153-3p enhances gefitinib-sensitivity in NSCLC by inhibiting autophagy via downregulating ATG5.
Subject(s)
Autophagy-Related Protein 5/genetics , Carcinoma, Non-Small-Cell Lung/genetics , Gefitinib/pharmacology , Lung Neoplasms/genetics , MicroRNAs/genetics , Autophagy/drug effects , Autophagy-Related Protein 5/metabolism , Carcinoma, Non-Small-Cell Lung/metabolism , Cell Line, Tumor , Cell Proliferation , Down-Regulation , Drug Resistance, Neoplasm , Humans , Lung Neoplasms/metabolism , Microtubule-Associated Proteins/metabolismABSTRACT
The synthesized Nd fluoride nanocrystals exhibited different upconversion behaviors as dispersed and aggregated samples due to the different energy transfer mechanisms. When they were dispersed in water, the NaNdF(4) nanocrystals exhibited approximately 400 times stronger upconversion fluorescence than the NdF(3) nanocrystals. Remarkable upconversion behaviors were found when the nanocrystals were aggregated in the films. For the NdF(3) nanocrystals, the energy transfer processes (4)I(13/2)<--(4)F(3/2)-->(4)G(7/2) in the films generated avalanche upconversion emissions with a high slope of approximately 12.0, which could be due to the large avalanche cross relaxation rates and spectral broadening effect. In contrast, the spectral broadening effect in the NaNdF(4) NCs films increased the energy transfer (4)I(15/2)<--(4)F(3/2)-->(4)G(5/2) of the Nd(3+) ions, and induced a new upconversion emission at approximately 680 nm with the slope increased from 1.0 to 3.2.
Subject(s)
Crystallization/methods , Fluorescence Resonance Energy Transfer/methods , Nanostructures/chemistry , Neodymium/chemistry , Energy Transfer , Nanostructures/ultrastructureABSTRACT
Cytotoxin-associated protein (cagA) and the vacuolating cytotoxin (vacA) encoded by cagA and vacA genes are virulence determinants of Helicobacter pylori. In earlier studies among Chinese patients, all H. pylori strains were cagA-positive and vacAs1a/m2 type. Here, we determine the cagA, vacA and allele status of H. pylori strains isolated from patients with upper gastrointestinal symptoms in Changsha, China. Forty strains of H. pylori isolated from patients with peptic ulcer disease between March 1997 and August 1999 were recovered from storage at -80 degrees C and studied by the polymerase chain reaction (PCR) for cagA and vacA genotypes. cagA was positive in 75% of H. pylori isolates. Patients with peptic ulcer demonstrated cagA in 83% (15/18), compared with 68% (15/22) patients with superficial gastritis. vacAs1 allele was carried in 82.5% (33/40) isolates, of which 52.5% (21/40) were subtype vacAs1a/m2 and 17.5% (7/40) were subtype vacAs1b/m2.
