UC San Diego

Resistance to chemotherapy is the primary cause of treatment failure in over 90% of cancer patients in the clinic. Research in nanotechnology-based therapeutic alternatives has helped provide innovative and promising strategies to overcome multidrug resistance (MDR). By targeting CD44-overexpressing MDR cancer cells, we have developed in a single-step a self-assembled, self-targetable, therapeutic semiconducting single-walled carbon nanotube (sSWCNT) drug delivery system that can deliver chemotherapeutic agents to both drug-sensitive OVCAR8 and resistant OVCAR8/ADR cancer cells. The novel nanoformula with a cholanic acid-derivatized hyaluronic acid (CAHA) biopolymer wrapped around a sSWCNT and loaded with doxorubicin (DOX), CAHA-sSWCNT-DOX, is much more effective in killing drug-resistant cancer cells compared to the free DOX and phospholipid PEG (PL-PEG)-modified sSWCNT formula, PEG-sSWCNT-DOX. The CAHA-sSWCNT-DOX affects the viscoelastic property more than free DOX and PL-PEG-sSWCNT-DOX, which in turn allows more drug molecules to be internalized. Intravenous injection of CAHA-sSWCNT-DOX (12 mg/kg DOX equivalent) followed by 808 nm laser irradiation (1 W/cm(2), 90 s) led to complete tumor eradication in a subcutaneous OVCAR8/ADR drug-resistant xenograft model, while free DOX alone failed to delay tumor growth. Our newly developed CAHA-sSWCNT-DOX nanoformula, which delivers therapeutics and acts as a sensitizer to influence drug uptake and induce apoptosis with minimal resistance factor, provides a novel effective means of counteracting the phenomenon of multidrug resistance.