Five-Part Pentameric Nanocomplex Shows Improved Efficacy of Doxorubicin in CD44+ Cancer Cells

The CD44 receptor is common among many cancer types where overexpression is synonymous with poor prognosis in prostate, glioma, and breast cancer. More notably CD44 overexpression has been shown in a number of different cancer stem cells (CSC) which are present in many solid tumors and drive growth, recurrence, and resistance to conventional therapies. Triple negative breast cancer CSCs correlate to worse prognosis and early relapse due to higher drug resistance and increased tumor heterogeneity and thus are prime targets for anticancer therapy. To specifically target cells overexpressing CD44 receptors, including CSCs, we synthesized a pentameric nanocomplex (PNC) containing gold nanoparticles, doxorubicin (Dox) conjugated to thiolated hyaluronic acid via an acid-labile hydrazone bond, and thiolated poly­(ethylene glycol) DNA CD44 aptamer. In vitro drug release was highest at 8 h time point at acidic pH (pH 4.7) and in 10 mM glutathione. The PNC is almost an order of magnitude more effective than Dox alone in CD44+ cells versus CD44 low cells. Functionally, the PNC reduced CSC self-renewal. The PNC provides a therapeutic strategy that can improve the efficiency of Dox and decrease nontargeted toxicity thereby prolonging its use to individual patients.