Enhancement of the Antitumor Efficacy of Docetaxel Using α_vβ₃ Integrin and CD44 Dual Receptor-Targeted Carbon Dot-Based Nanodelivery in Breast Cancer

Breast cancer is one of the most common forms of cancer, and an alternate treatment strategy for breast cancer is of utmost importance, as conventional therapy brings severe side effects. Here, we have developed a hyaluronic acid (HA) and cyclic arginine-glycine-aspartic acid peptide (cRGD)-conjugated docetaxel (DTX)-loaded nitrogen-doped carbon dot (CDU)-targeted delivery system for breast cancer. The developed dual-ligand-conjugated system (cRGD-HA-CDU@DTX) has exhibited a size below 100 nm, a high ζ potential (-24.3 mV), good biocompatibility, and good hydrophilicity. The cRGD-HA-CDU@DTX system has demonstrated a high drug loading efficiency (77.53%) and shown an acidic pH (pH 5.0)-dependent drug release of 90% after 48 h. According to the <i>in vitro</i> cytotoxicity study in the Michigan Cancer Foundation-7 (MCF-7) cancer cell line, the IC₅₀ value for the cRGD-HA-CDU@DTX system is found to be 3.167 μM, while for DTX, it is found to be 4.068 μM, indicating better cytotoxicity of the dual-ligand-conjugated system. Cellular uptake study exhibited the excellent internalization of the dual-ligand-conjugated system and a higher reactive oxygen species (ROS) production in cRGD-HA-CDU@DTX as compared to native DTX is seen. Flow cytometry analysis in MCF-7 cells demonstrated an almost 3-fold increased apoptotic cell death for the cRGD-HA-CDU@DTX group compared to DTX alone. Additionally, cell cycle analysis revealed 15% G₂/M arrest in the cRGD-HA-CDU@DTX-treated cells, whereas only 3.6% G₂/M arrest was noted for DTX. Further, the cRGD-HA-CDU@DTX system exhibited a significant upregulation and downregulation of proapoptotic and antiapoptotic genes, respectively. Finally, <i>in vivo</i> antitumor study displayed a 64.12% tumor growth reduction in the cRGD-HA-CDU@DTX-treated group, while DTX exhibited only a 39.98% tumor growth reduction. Thus, the overall study demonstrated that the cRGD-HA-CDU@DTX system can serve as a potential targeted nanodrug delivery system to reduce side effects and to improve therapeutic efficacy in breast cancer.