Detection of specific extracellular RNAs has been developed for non-invasive cancer diagnosis. However, accurate and efficient identification of RNAs with single-point mutation in cancer cells-derived extracellular vesicles (EVs) is challenging. Researchers from The Ohio State University present a unique overhang molecular beacon with internal dye (Ohi-MB) with a stable hairpin structure, fast hybridization kinetics and single mismatch specificity. Ohi-MBs are encapsulated in cationic lipoplex nanoparticles (CLNs) that are tethered on a gold coated glass slide as a chip, which can capture circulating EVs and detect encapsulated target RNAs in-situ in a single step. The capability of detection of single-point mutation by CLN-Ohi-MB is demonstrated in artificial EVs and cancer cells. This CLN-Ohi-MB biochip could quantify single-point mutations in KRAS mRNA (G12C, G12D, G12V) in pancreatic cancer cell-derived EVs and single-point mutations in EGFR mRNA (L858R and T790M) in lung cancer cell-derived EVs with high specificity, not achievable by conventional molecular probes. The researchers show that CLN-Ohi-MB biochip could selectively and sensitively identify single-point mutations in KRAS mRNA in human serum EVs, distinguishing pancreatic cancer patients with different mutations.
Detection of single-point mutation in extracellular vesicle-associated RNAs with molecular beacons
Hu J, Kwak KJ, Shi J, Yu B, Sheng Y, Lee LJ. (2018) Overhang molecular beacons encapsulated in tethered cationic lipoplex nanoparticles for detection of single-point mutation in extracellular vesicle-associated RNAs. Biomaterials 183:20-29. [abstract]