MicroRNA Expression Signature in Human Glioblastoma Multiforme Brain Tumor
Expression of 180 human miRNAs was examined using recently developed stem loop primers for reverse transcription (RT) followed by real-time PCR. MicroRNAs can be quantified from as few as single cells or as little as 25 pg total RNA. The CT values correlated to the copy number over up to seven orders of magnitude. TheTaqMan® miRNA assays discriminated between two miRNAs that differed by as little as a single nucleotide, and between mature miRNAs and their precursors.
This method allows accurate and sensitive miRNA expression profiling and uncovers precise changes of miRNA expression. Comparing to normal human brain, the glioblastoma multiforme (GBM) tumors have a distinct expression signature of miRNAs. Nearly half of miRNAs showed the reduced expression by > 2-folds. In contrast, only 13% miRNAs had increased expression (>2-folds) in GBM. Expression of miR-10a and miR-10b etc. located within class I HOX and miR-129, miR-139,and miR-153 etc. within class II HOX gene clusters is either elevated or reduced (>10-fold), suggesting that these miRNAs may be involved in brain cancers.