Application of Dual-Targeting Carbon Dot Nanozymes in Improving Hypoxia and Enhancing Small Interfering RNA-Mediated Gene Silencing for Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a malignant tumor with high morbidity and mortality, and current therapeutic effects remain unsatisfactory. Small interfering RNA (siRNA) therapy has attracted widespread attention owing to its strong specificity and high silencing efficiency. Golgi apparatus (GA) protein 73 (GP73) is overexpressed in HCC and promotes proliferation and invasion of HCC. However, the hypoxic microenvironment of HCC facilitates GP73 synthesis. Based on the bidirectional regulation between GP73 and the hypoxic microenvironment, this study proposes the use of carbon dot nanozyme with dual-targeting properties to deliver GP73-siRNA to the GA of HCC cells, thereby inhibiting GP73 expression and simultaneously alleviating hypoxia for synergistic HCC treatment and improved efficacy. Specifically, GA targeting manganese-doped carbon dot nanozyme (Mn-CDs) was constructed using neutral red (with a large sp2 conjugated structure), L-cysteine (GA targeting agent), and manganese dioxide as raw materials via a one-step solvothermal method. Polyethyleneimine (PEI) and hyaluronic acid (HA) were modified on the surface of Mn-CDs to obtain the dual-targeting Mn-CDs-PEI-HA. Subsequently, Mn-CDs-PEI-HA was used as a carrier to load GP73-siRNA and form the Mn-CDs-PEI-HA/GP73-siRNA complex. Results demonstrated that the complex exhibited excellent catalase-like enzyme activity, which can alleviate tumor hypoxia, and could deliver GP73-siRNA to the GA of HCC cells, thereby silencing GP73 expression and synergistically inhibiting HCC progression. The therapeutic effect under hypoxic conditions was superior to that under normoxic conditions. Additionally, by simultaneously taking advantage of the favorable fluorescence and magnetic properties of Mn-CDs-PEI-HA, fluorescence/magnetic resonance dual-modality imaging of HCC was achieved, providing a new strategy for theranostics of HCC.