Functionalized graphene oxide as a nanocarrier for multiple suppressive miRNAs to inhibit human intrahepatic cholangiocarcinoma

Abstract

AbstractThe restoration of suppressed miRNAs is a promising therapeutic approach for treating tumors; however, efficient delivery remains a challenge. Herein, we aimed to develop a polyethylenimine (PEI) functionalized graphene oxide nanosheets (GO‐PEI) as a suppressive miRNA delivery system to treat human intrahepatic cholangiocarcinoma (ICC). We found that the GO‐PEI complex possessed excellent transfection efficacy and acceptable toxicity. Furthermore, using our miRNA array analysis and The Cancer Genome Atlas (TCGA) dataset, we selected four miRNAs (miR‐194‐5p, miR‐125b‐5p, miR‐122‐5p, and let‐7c‐5p) that are remarkably downregulated in ICC samples compared to that in adjacent tissues. The GO‐PEI complexed with the four miRNAs (GO‐PEI‐4miR) achieved a higher miRNA transfection efficiency than Lipo2000, as verified by quantitative reverse transcription polymerase chain reaction (qRT‐PCR) assays, immunofluorescence, and flow cytometry analyses. In addition, in vitro experiments revealed that GO‐PEI‐4miR remarkably restored the repressed miRNAs, thereby significantly repressing tumor sphere formation, colony formation, drug resistance, and markedly inhibiting the target genes of these miRNAs and cancer stem cell‐related markers. Furthermore, both tumor weights and bioluminescent imaging analysis indicated that the GO‐PEI‐4miR significantly reduced tumor formation in vivo. Taken together, these results demonstrate that GO‐PEI could be a potential delivery system for multiple repressive miRNAs in ICC therapy.