Background: Aberrant expression of microRNAs in neoplastic lesions may serve as potential personalized therapeutic targets. To inhibit oncogenic microRNAs (oncomiRs) expression and restore tumor suppressor proteins, linear miRNA sponges have been developed, leading to several drugs in clinical trials. Despite their efficacy, chemically synthesized miRNA inhibitors face challenges with sustained inhibition and high production costs, hindering widespread clinical adoption. Additionally, single-stranded circular RNAs (circRNAs) act as miRNA sponges, enhancing protein expression and demonstrating stability and therapeutic potential in cancer treatment. Our approach involves the use of synthetic single-stranded circular nucleic acids, including circDNA and circRNA, to selectively target and inhibit a variety of aberrantly overexpressed oncomiRs in tumors. The objective of this strategy is to restore the expression levels of multiple tumor suppressor factors and to suppress the malignant progression of tumors. Methods: Our methodology comprises a two-step process. First, we identified tumor suppressor genes (TSGs) with abnormally low expression in hepatocellular carcinoma (HCC) tumor cells by transcriptomic analysis and targeted the upstream cancer miRNA clusters of these TSGs. Second, we designed and validated a fully complementary circDNA or circRNA construct, ligated by T4 DNA ligase or T4 RNA ligase, respectively, that specifically targets the sponge oncomiRs both in vitro and in vivo to inhibit the malignant progression of HCC. Results: CircNAs demonstrated superior, long-lasting therapeutic efficacy against HCC compared to inhibitors. Furthermore, we compared the immune effects in vivo of three different nucleic acid adsorption carriers, including commercial miRNA inhibitor, circDNA, and circRNA. We found that the miRNA inhibitor activates a more robust inflammatory response compared to circDNA and circRNA. Conclusions: These findings underscore the substantial therapeutic potential of circDNA in tumorigenesis and provide novel insights for the formulation of personalized treatment plans for malignant tumors, such as HCC.

The incidence of type 2 diabetes mellitus (T2DM) induced by obesity is rapidly increasing. Although there are many synthetic drugs for treating T2DM, they have various side effects. Here, we report that miR8175, a plant miRNA from burdock root, has effective antidiabetic activity. After administration of burdock decoction or synthetic miR8175 by gavage, both burdock decoction and miR8175 can significantly improve the impaired glucose metabolism of diabetic mice induced by a high-fat diet (HFD). Our results demonstrate that burdock decoction and miR8175 enhance the insulin sensitivity of the hepatic insulin signaling pathway by targeting Ptprf and Ptp1b, which may be the reason for the improvement in metabolism. This study provides a theoretical basis for the main active component and molecular mechanism of burdock to improve insulin resistance. And the study also suggests that plant miRNA may be an indispensable nutrient for maintaining human health.

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