ABSTRACT
OBJECTIVE: To investigate the effect of elemene on the radiosensitivity of A549 cells and its possible molecular mechanism. METHODS: Apoptosis of A549 cells was detected by flow cytometry and fluorescence microscopy. The effect of double-strand break (DSB) damage repair in A549 cells was evaluated using the neutral comet assay. Protein expression levels were detected using western blotting, and the correlation between protein levels was analyzed. RESULTS: Elemene exhibited a radiosensitizing effect on A549 cells. The level of apoptosis induced by elemene combined with radiation was significantly greater (p<0.01) than that elicited by either radiation or elemene alone. Following radiation and subsequent repair for 24 h, the tail intensity of A549 cells treated with a combination of elemene and radiation was greater than that of cells treated with either elemene or radiation alone (p<0.01). This result indicates that elemene inhibits cellular DSB repair. Both elemene combined with radiation and radiation alone decreased the protein expression of DNA-PKcs and Bcl-2 compared to elemene alone (p<0.01), while p53 protein expression was increased (p<0.01). A negative correlation was observed between DNA-PKcs and p53 expression (r=−0.569, p=0.040), while a positive correlation was found between DNA-PKcs and Bcl-2 expression (r=0.755, p=0.012). CONCLUSIONS: Elemene exhibits a radiosensitizing effect on A549 cells, and its underlying molecular mechanism of action may be related to the downregulation of DNA-PKcs gene expression. .
Subject(s)
Humans , Adenocarcinoma/radiotherapy , Lung Neoplasms/radiotherapy , Radiation Tolerance/radiation effects , Radiation-Sensitizing Agents/pharmacology , Sesquiterpenes/pharmacology , Analysis of Variance , Adenocarcinoma/drug therapy , Adenocarcinoma/genetics , Apoptosis/drug effects , Apoptosis/radiation effects , Blotting, Western , Cell Line, Tumor , Comet Assay , Cell Survival/drug effects , Cell Survival/radiation effects , DNA Repair/drug effects , DNA Repair/radiation effects , DNA-Activated Protein Kinase/metabolism , Flow Cytometry , Gene Expression Regulation/drug effects , Gene Expression Regulation/radiation effects , Lung Neoplasms/drug therapy , Lung Neoplasms/genetics , Microscopy, Fluorescence , Radiation Dosage , Radiation Tolerance/drug effects , /metabolismABSTRACT
An International Study of Asthma and Allergy in Childhood (ISAAC) revealed a wide range of prevalences of childhood asthma in the world. Lao PDR had no such epidemiological data yet. This study aimed to investigate the epidemiology of asthma, rhinitis, and eczema in children in the country. A cross-sectional study was conducted in Vientiane City, the capital of Lao PDR, in 1997 using the ISAAC questionnaire. From three primary schools and one high school, 395 children, age 6-7 years, and 468 children, age 13-14 years, were chosen. The prevalence of asthma for children aged 13-14 years in Lao PDR was 25.6%, which ranks the highest in international asthma prevalence. The prevalence in allergic-rhinoconjunctivitis of children was 24.4% and atopic eczema was 7.1%. Contrary to generally accepted risk factors, there were no associations revealed between asthma prevalence and smoking of family members (especially mothers), intake of fish/meat, and male gender.