Triplex DNA-based aggregation-induced emission probe: A new platform for hybridization chain reaction-based fluorescence sensing assay.

The hybridization chain reaction (HCR), as one of the nucleic acid amplification technologies, is combined with fluorescence signal output with excellent sensitivity, simplicity, and stability. However, current HCR-based fluorescence sensing methods still have some defects such as the blocking effect of the HCR combination with fluorophores and the aggregation-caused quenching (ACQ) phenomenon of traditional fluorophores. Herein, a triplex DNA-based aggregation-induced emission probe (AIE-P) was designed as the fluorescent signal transduction, which is able to provide a new platform for HCR-based sensing assay. The AIE-P was synthesized by attaching the AIE fluorophores to terminus of the oligonucleotide through amido bond, and captured the products of HCR to form triplex DNA. In this case, the AIE fluorophores were located in close proximity to generate fluorescence. This assay provided turn-on fluorescence efficiency with a high signal-to-noise ratio and excellent amplification capability to solve the shortcoming of HCR-based fluorescence sensing methods. It enabled sensitive detection of Vibrio parahaemolyticus in the range of 102-106 CFU mL-1, and with a low limit of detection down to 39 CFU mL-1. In addition, this assay expressed good specificity and practicability. The triplex DNA-based AIE probe forms a universal molecular tool for developing HCR-based fluorescence sensing methods.

Overexpression of Bmi­1 promotes epithelial­mesenchymal transition in CD133+Hep G2 cells.

Cancer stem cells (CSCs) and epithelial­mesenchymal transition (EMT) are critical factors contributing to tumor metastasis and recurrence. The BMI1 proto­oncogene (Bmi­1) promotes the development and progression of hematologic malignancies and of several types of solid tumors. The aim of the present study was to explore the mechanism by which Bmi­1 may promote invasion and migration of hepatocellular carcinoma Hep G2 cells. CD133 antigen is a transmembrane glycoprotein and regarded as a cancer stem cells marker in hepatocellular carcinoma. CD133+Hep G2 cells were enriched by magnetic­activated cell sorting and exhibited greater viability compared with CD133­Hep G2 cells, as measured by Cell Counting kit­8 assay. Then, Bmi­1 was overexpressed in CD133+Hep G2 cells by transfection with the Bmi­1/pcDNA3.1(+) expression plasmid, and overexpression was confirmed by reverse­transcription­polymerase chain reaction and western blotting. Overexpression of Bmi­1in CD133+Hep G2 cells resulted in the downregulation of E­cadherin and upregulation of Vimentin at the protein level. The invasion and migration abilities of CD133+Hep G2 cells were increased in the Bmi­1/pcDNA3.1(+)­transfected group, as measured by Transwell invasion and wound healing assays, respectively. In conclusion, Bmi­1 promoted invasion and migration of CD133+Hep G2 cells most likely through inducing EMT. The present findings may offer a potential novel target for the development of hepatocellular carcinoma therapies.