A biosensor based on solid-state nanochannels of anodic aluminum oxide (AAO) membrane for both electrochemical and naked-eye detection of microRNA-31 (MiR-31) is proposed. For this purpose, MoS 2 nanosheets, which possess different adsorption capabilities to single-stranded and double-stranded nucleic acids, are deposited onto the top surface of the AAO membrane. Moreover, multi-functional DNA nanostructure have been designed by linking a G-rich sequence for folding to a G- quadruplex at three vertices and a complementary sequence of MiR-31 at the other one vertex of a DNA tetrahedron. In the absence of MiR-31, the tetrahedron DNAzyme probe formed after the addition of hemin can mediate the deposition of insoluble on MoS 2 /AAO, which not only enables the color change of the membrane but also gates the transport of K 3 [Fe(CN) 6 ] across the nanochannels. Therefore, the detection of MiR-31 is realized by both visual observation of the brown color and measuring the electrochemical redox current of [Fe(CN) 6 ] 3 − . Using this biosensor, a detection limit as low as 0.06 fM is achieved. The dual-mode detection method also exhibits good specificity, reproducibility, and stability, demonstrating potential application in the diagnosis of oral squamous cell carcinoma and other related biological purposes. Graphical
Mu Yanan,Lian Chen,Chen Xinghui,Yang Xueying,Li Dongxia,Zhang Yi
Tumor-derived exosomes that transport MicroRNAs significantly influence cutaneous squamous cell carcinoma(CSCC) progression. However, the molecular mechanisms of exosomal MicroRNA-31 regulation of CSCC are mostly undefined. To determine whether a targeting relationship exists between MicroRNA-31 (miR-31) in CSCC-derived exosomes and the tumor suppressor RhoBTB1, and the regulatory effect of the relationship on tumor cells. Immunoblotting and quantitative PCR were used to measure miR-31 and RhoBTB1 levels in various cells and exosomes. Differential ultracentrifugation was used to isolate exosomes. MTT and Transwell assays were used to assess cell proliferation, migration, and invasion. Dual luciferase reporter assays were used to assess the direct interaction between miR-31 and the tumor suppressor RhoBTB1 in cutaneous squamous cell carcinoma (CSCC)-derived exosomes. Compared with a human skin keratinocyte cell line, in CSCC cell lines RhoBTB1 was downregulated and miR-31 levels were elevated. Exosomal miR-31 from CSCC cell lines directly targeted RhoBTB1 by binding to the 3’ UTR of RhoBTB1. This interaction suppressed expression of RhoBTB1 and enhanced CSCC cell proliferation, migration, and invasion. MicroRNA-31 in CSCC-derived exosomes can enhance CSCC cell proliferation, migration, and invasion by suppressing expression of RhoBTB1. This finding explains, in part, the molecular mechanism of CSCC. Investigative approaches focused on suppressing miR-31 or enhancing RhoBTB1 signaling pathways are promising avenues for developing targeted therapies for CSCC.
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