METHOD: By using the keywords "acute lymphoblastic leukemia", and "microarray", a total of 280 and 275 microarray datasets were found listed in Gene Expression Omnibus database GEO and ArrayExpress database respectively. Further manual inspection found that only three studies (GSE18497, GSE28460, GSE3910) were focused on gene expression profiling of paired diagnosis-relapsed pediatric B-ALL. These three datasets which comprised of a total of 108 matched diagnosis-relapsed pediatric B-ALL samples were then included for this meta-analysis using RankProd approach.
RESULTS: Our analysis identified a total of 1795 upregulated probes which corresponded to 1527 genes (pfp 1), and 1493 downregulated probes which corresponded to 1214 genes (pfp gene (pfp gene ontology biological process annotation, the upregulated genes were most enriched in cell cycle processes (enrichment score = 15.3), whilst the downregulated genes were clustered in transcription regulation (enrichment score = 12.6). Elevated expression of cell cycle regulators (e.g kinesins, AURKA, CDKs) was the key genetic defect implicated in relapsed ALL, and serve as attractive targets for therapeutic intervention.
CONCLUSION: We identified S100A8 as the most overexpressed gene, and the cell cycle pathway as the most promising biomarker and therapeutic target for relapsed childhood B-ALL. The validity of the results warrants further investigation.
AIMS: In this study, we investigated the effects of mitragynine on dopamine (DA) level and dopamine transporter (DAT) expression from the rat's frontal cortex.
METHODS: DA level was recorded in the brain samples of animals treated with acute or repeated exposure for 4 consecutive days with either vehicle or mitragynine (1 and 30 mg/kg) using electrochemical sensor. Animals were then decapitated and the brain regions were removed, snap-frozen in liquid nitrogen and immediately stored at -80 °C. DA level was quantified using Enzyme linked immunosorbent assay (ELISA) kits and DAT gene expression was determined using quantitative real time polymerase chain reaction (RT-qPCR).
RESULTS/OUTCOME: Mitragynine (1 and 30 mg/kg) did not increase DA release following acute treatment, however, after repeated exposure at day 4, mitragynine significantly and dose dependently increased DA release in the frontal cortex. In this study, we also observed a significant increase in DAT mRNA expression at day 4 in group treated with mitragynine (30 mg/kg).
CONCLUSION/INTERPRETATION: Data from this study indicates that mitragynine significantly increased DA release when administered repeatedly, increased in DAT mRNA expression with the highest tested dose (30 mg/kg). Therefore, the rewarding effects observed after mitragynine administration could be due to its ability to increase DA content in certain areas of the brain especially the frontal cortex.