Abstract

Background: MiR-196a is particularly noticeable in the development of liver cancer. However, the rapid degradation by ribonuclease (RNase) imposes a limit on the miRNA gene therapy applications.
Aims: To design a novel gene-targeting nano system for liver cancer treatment.
Study Design: Cell culture study and animal experimentation
Methods: Deacetylated (DEAC)-poly-N-acetylglucosamine (PNAG)-folic acid (FA) was prepared via ethyl (dimethylaminopropyl) carbodiimide/N-hydroxysuccinimide reaction, and miR-196a inhibitor (miR-196a I)/DEAC-PNAG-FA was prepared through self-assembly. The characterization and nucleic acid protection of the self-assembly system were also determined. The biological function and related mechanism of the prepared system were studied at cellular and molecular levels. Mice were established as a xenotransplantation model to evaluate the anticancer capacity of miR-196a I/DEAC-PNAG-FA in vivo.
Results: The morphology of miR-196a I/DEAC-PNAG-FA was uniform, and its particle size was approximately 70–100 nm. A nanocarrier with an N/P ratio of 200:1 can maximize the nucleic acid carrying capacity of the self-assembly system. The nanosystem can protect miRNA from RNase degradation and could be internalized rapidly within 4 h. The self-assembly system significantly enhanced the apoptosis-inducing effect of miR-196a I on HepG2 cells (P = 0.003). Molecular biological analyses confirmed that the apoptosis-inducing effect of the nanosystem was due to the inhibition of miR-196a gene expression in HepG2 cells, which upregulate the expression of pro-apoptotic proteins FOXO1 (P < 0.001), Bax (P < 0.001), Ki67 (P < 0.001), and proliferating cell nuclear antigen (P < 0.001), and inhibit the expression of apoptosis inhibitory protein Bcl-2 (P < 0.001). Moreover, compared with free miR-196a inhibitor or miR-196a I/DEAC-PNAG, miR-196a I/DEAC-PNAG-FA can more effectively inhibit tumor growth in vivo (P = 0.026).
Conclusion: The newly prepared self-assembly targeting system can effectively induce apoptosis and abrogate tumor growth, which may open a new approach for liver cancer treatment.