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Objective To investigate the effects of exosome-derived miR-1246 on metastasis and autophagy of esophageal squamous cell carcinoma(ESCC).Methods The exosomes of ESCC cells were extracted by exosome extraction kit,the morphology was observed under electron microscope,the particle size was detected by nano-particle size analyzer,and the expression of exosome markers TSG101 and Calnexin was detected by Western blot.The RNA of exosomes of ESCC cells and normal esophageal epithelial cells were sequenced to analyze the differentially expressed miRNAs,which were analyzed by KEGG Pathway enrichment.The expression of miR-1246 in tumor tissues and paracancer tissues of 155 patients with ESCC was evaluated by transcriptome sequencing.The effect of miR-1246 on the migration ability of ESCC cells was detected by Transwell assay and the effect on autophagy was detected by Western blot.Results The exosomes derived from ESCC cells were intact in shape and similar to spherical vesicle-like structure with the particle size of 50～80 nm.The exosome marker TSG101 protein was positive and Calnexin protein was negative.There were 59 common differentially expressed miRNAs between exosomes of ESCC cells and normal esophageal epithelial cells.Exosome miR-1246 was highly expressed in ESCC cells,and the differentially expressed miRNAs were mainly enriched in autophagy metabolic pathway.Exosome miR-1246 was highly expressed in cancer tissues of patients with ESCC.Overexpression of miR-1246 significantly promoted the migration and autophagy of ESCC cells(t=4.119 and 48.150,P <0.05 and <0.001,respectively).Inhibition of miR-1246 expression inhibited the migration and autophagy of ESCC cells(t=9.067 and 51.270,P <0.01 and <0.001,respectively).Conclusion miR-1246 derived from exosomes can significantly affect the metastasis and autophagy of ESCC cells.

7.Construction and self-activation detection of yeast two-hybrid bait plasmid of human programmed cell death ligand 1 immunoglobulin variable region domain gene

LIU Peng

Chinese Journal of Biologicals 2024;37(1):8-16

Objective To construct a yeast two-hybrid recombinant bait plasmid of human programmed cell death ligand 1(PD-L1)immunoglobulin variable region(IgV)domain gene,detect its expression in yeast and detect the cytotoxicity and self-activation of PD-L1 IgV protein as well as the interaction between PD-L1 IgV and human thioredoxin(hTrx).Methods Human PD-L1 was analyzed by bioinformatics method,and primers were designed to amplify PD-L1 IgV domain based on the coding region of PD-L1 gene registered in NCBI GenBank database. PCR amplification was carried out with pENTERPD-L1 plasmid as template,and then cloned into yeast two-hybrid bait vector pGBKT7. The recombinant bait plasmid and pGBKT7 empty vector were transformed into Y2HGold yeast cells respectively,and the PD-L1 IgV gene and its expression were detected by PCR and Western blot;Meanwhile,the protein toxicity and self-activation of PD-L1 IgV were detected,and the interaction between PD-L1 IgV and hTrx was detected by drip plate method.Results The bioinformatics analysis results of PD-L1 were consistent with related reports. The recombinant bait plasmid pGBKT7-PD-L1 IgV was correctly constructed,and Y2HGold positive clone was obtained,in which PD-L1 IgV was stably expressed. The empty vector pGBKT7 and recombinant bait plasmid pGBKT7-PD-L1 IgV grew well on SD/-Trp and SD/-Trp/X-α-Gal plates with the same colony size and number and white colony,but they did not grow on SD/-Trp/X-α-Gal/AbA plates,which indicated that PD-L1 IgV protein had no toxicity and no self-activation effect on yeast. The results of drip plates test showed that all experimental groups grew well on SD/-Trp/-Leu plate,while only positive control group grew on SD/-Trp/-Leu/X-α-Gal/AbA plate and showed blue color,which indicated that bait protein PD-L1 IgV and hTrx did not self-activate,and there was no interaction between them.Conclusion Recombinant human PD-L1 IgV bait plasmid was successfully constructed. PD-L1 IgV protein showed no toxicity and self-activation effect on yeast cells,and there was no interaction between PD-L1 IgV and hTrx. Subsequently,hTrx can be used to construct a peptide aptamer library,from which peptide aptamers that specifically bind to PD-L1 IgV can be screened.