Selective and sensitive detection of chronic myeloid leukemia using fluorogenic DNAzyme probes

One of the major challenges facing the early diagnosis of chronic myelogenous leukemia (CML) patients today is enhancing the simplicity, rapidness, sensitivity and specificity of detection assay for easy clinical implementation. RNA-cleaving fluorogenic DNAzymes (RFDs) are single-stranded DNA molecules with catalytic activity and can produce fluorescent signals when combined with specific targets. As K562 cells were the first established human immortalized myelogenous leukemia line, we try to screen several RFDs using the crude extracellular mixture of K562 cells through the SELEX process. We obtained an RFD probe A1-3 that is able to distinguish K562 cells from other tumor cell lines. 10 nM of A1-3 can induce an increase of detectable fluorescence signal. Moreover, the RFD assay system can work well for target detection in complex serum matrix. The optimized RFD assay system with low cost also has a desirable ability to exactly distinguish K562 cells after truncation of 20 bases in the 5'end of A1-3. This study is the first report to investigate the RFD system for detection of K562 cells using cell culture supernatants as the complex target. This RFD assay system could potentially be applied for the diagnosis of CML.