Development of protein-conjugated spion-based theranostic nanoparticles as small rna gene therapy vehicles in cancer treatment

Theranostic approaches in nanoparticles depending on the design and functional modifications might allow multipurpose usage of these nanoparticles including diagnosis, treatment and follow-up diseases. SPIONs are superparamagnetic iron oxide (Fe3O4) nanoparticles have magnetic properties those can be detected and manipulated under magnetic field. SPION nanoparticles are biocompatible particles and suitable for functional modifications which allow their usage as gene therapy vector. All these advantages potentiate usage of SPIONs as efficient and targeted drug and nucleic acid delivery agent for gene therapy purposes. Recent studies over a decade introduced small RNAs including microRNAs as novel cancer diagnosis and therapy tools. Non-viral gene regulation via miRNAs requires the development of materials that can safely deliver miRNAs into cells. A key challenge in delivery of miRNAs into cells is developing materials that can protect miRNA strands from surrounding RNase. Protein-based approaches address this problem by taking advantage of their RNA binding and stabilizing effects. In this study, we present SPION-based novel and targeted miRNA delivery tool for gene therapy of breast cancer. These delivery agents were composed of a SPION core that was functionalized by the addition of fluorophore-tagged anti-HER2 antibodies as targeting agents. SPION nanoparticles are designed to be internalized by Herceptin receptor overexpressing breast cancer cells via receptor-mediated endocytosis. We also propose for the first-time, the usage of a protein as a microRNA stabilizer and a delivery vehicle. SPION/A/HER2 (SP-AH) nanoparticles can deliver autophagy inhibitory microRNA, MIR376B into HER2-positive breast cancer cell lines (SKBR3 and MDA-MB-453) in vitro and in a xenograft nude mice model of breast cancer in vivo. Autophagic activity is also efficiently inhibited in cells and xenografted tumor model under these conditions. More importantly, combination of MIR376B-loaded SP-AH nanoparticles with chemotherapy agent cisplatin potentiated anti-cancer treatment efficacy both in vitro and in vivo systems. Therefore, we introduce the protein containing theranostic nanoparticles as a powerful miRNA carrier and stabilizer tool to be used in novel microRNA-based targeted gene therapy approaches for cancer