Fig. 9

NPs-mediated upregulation of circPDE5A and PDE5A-500aa inhibits ESCC cell proliferation and metastasis in vitro. A Schematic illustration of the reduction-responsive circRNA nanoplatforms made with the cationic lipid-like compound G0-C14 and amphiphilic copolymer Meo-PEG-S–S-PLGA. B–C Transmission electron microscope image (B) and size distribution (C) of NPs (circPDE5A) in aqueous solution. Bar in (B) represents 200 μm. D RT-qPCR analysis of the relative level of circPDE5A after treatment of ESCC cells with different doses of NPs (circPDE5A). E Confocal fluorescence microscopy to detect the uptake of Cy5-circRNA by ESCC cells in response to different treatment groups. Bar represents 5 μm. F Flow cytometric analysis of Cy5-circRNA uptake by ESCC cells in response to different treatment groups. G Fluorescence imaging of the ESCC subcutaneous tumor model in nude mice after tail vein injection of naked Cy5-circPDE5A plasmid and NPs (Cy5-circPDE5A). H Fluorescence imaging of isolated major organs and tumors in nude mice after tail vein injection of naked Cy5-circPDE5A plasmid and NPs (Cy5-circPDE5A). I The proliferative capacity of ESCC cells was detected by plate cloning assay after treatment with NPs (vector), naked circPDE5A plasmid, NPs (circPDE5A), NPs (circPDE5A-Mut), and NPs (PDE5A-500aa). J Migration and invasion ability of ESCC cells determined by transwell assay after treatment with NPs (vector), naked circPDE5A plasmid, NPs (circPDE5A), NPs (circPDE5A-Mut), and NPs (PDE5A-500aa). Bar represents 1,000 μm. ***P < 0.005. ns, not significant