Self-Assembly of Antisense DNA-Camptothecin Amphiphile into Glutathione-Responsive Nanoparticles for Combination Cancer Therapy

Recent years have witnessed the rapid growth of combination therapy for the treatment of cancer. Chemo and antisense DNA therapies are two clinically proven and efficient treatment modalities for cancer. However, direct delivery of both chemo and antisense oligonucleotides into the cancerous cells is challenging and hence there is a high demand for the development of new strategies that permit the direct delivery of chemo and antisense therapeutic agents in a targeted fashion. Herein, we show a supramolecular approach for the direct delivery of hydrophobic chemo drug and cell impermeable antisense oligonucleotide into a cancer cell in a targeted fashion. Synthesis of an amphiphile (DNA1-CPT) consist of hydrophobic camptothecin (CPT) conjugated to an antisense oligonucleotide (DNA1) via glutathione-responsive disulphide linker is reported. Self-assembly of DNA1-CPT results in the formation of GSH-responsive NPs with CPT as the hydrophobic core and DNA1 as the hydrophilic shell. Self-assembled NPs exhibits excellent cellular internalization via endocytosis pathway, and the high concentration of glutathione inside the cancer cells causes the cleavage of disulphide bond of the NPs and trigger the simultaneous release of CPT and DNA1a. Enhanced cytotoxicity is observed for the NPs due to the synergetic combination of chemo and antisense DNA therapies.

Multifunctional siRNA/ferrocene/cyclodextrin nanoparticles for enhanced chemodynamic cancer therapy

The therapeutic outcome of chemodynamic therapy (CDT) is greatly hindered by the presence of oxidative damage repair proteins (MTH1) inside cancer cells. These oxidative damage repair proteins detoxify the action of radicals generated by Fenton or Fenton-like reactions. Hence, it is extremely important to develop a simple strategy for the downregulation of MTH1 protein inside cancer cells along with the delivery of metal ions into cancer cells. A one-pot host-guest supramolecular approach for the codelivery of MTH1 siRNA and metal ions into a cancer cell is reported. Our approach involves the fabrication of an inclusion complex between cationic β-cyclodextrin and a ferrocene prodrug, which spontaneously undergoes amphiphilicity-driven self-assembly to form spherical nanoparticles (NPs) having a positively charged surface. The cationic surface of the NPs was then explored for the loading of MTH1 siRNA through electrostatic interactions. Using HeLa cells as a representative example, efficient uptake of the NPs, delivery of MTH1 siRNA and the enhanced CDT of the nanoformulation are demonstrated. This work highlights the potential of the supramolecular approach as a simple yet efficient method for the delivery of siRNA across the cell membrane for enhanced chemodynamic therapy.