New retinoblastoma (RB) drug delivery approaches: anti-tumor effect of atrial natriuretic peptide (ANP)-conjugated hyaluronic-acid-coated gold nanoparticles for intraocular treatment of chemoresistant RB.

Intraocular drug delivery is a promising approach for treatment of ocular diseases. Chemotherapeutic drugs used in retinoblastoma (RB) treatment often lead to side effects and drug resistances. Therefore, new adjuvant therapies are needed to treat chemoresistant RBs. Biocompatible gold nanoparticles (GNPs) have unique antiangiogenic properties and can inhibit cancer progression. The combination of gold and low-molecular-weight hyaluronan (HA) enhances the stability of GNPs and promotes the distribution across ocular barriers. Attached to HA-GNPs, the atrial natriuretic peptide (ANP), which diminishes neovascularization in the eye, is a promising new therapeutic agent for RB treatment. In the study presented, we established ANP-coupled HA-GNPs and investigated their effect on the tumor formation potential of chemoresistant RB cells in an in ovo chicken chorioallantoic membrane model and an orthotopic in vivo RB rat eye model. Treatment of etoposide-resistant RB cells with ANP-HA-GNPs in ovo resulted in significantly reduced tumor growth and angiogenesis compared with controls. The antitumorigenic effect could be verified in the rat eye model, including a noninvasive application form via eye drops. Our data suggest that ANP-HA-GNPs represent a new minimally invasive, adjuvant treatment option for RB.

Solid lipid nanoparticles as non-viral vector for the treatment of chronic hepatitis C by RNA interference.

RNA interference (RNAi) is a promising strategy to treat the chronic infection by hepatitis C virus (HCV). The objective of this work was to develop a non-viral vector based on solid lipid nanoparticles (SLN) and RNAi to inhibit the internal ribosome entry site (IRES) mechanism of the HCV. The vectors were prepared with SLN, protamine, hylauronic acid (HA) or dextran (DX), and a short-hairpin RNA expression plasmid targeted to the stem loop II of the 5' UTR (shRNA74). The particle size, surface charge, and capacity to bind, release and protect the shRNA74 against nucleases were evaluated. Cell uptake, silencing capacity and cell viability were evaluated in HepG2 cells. All the vectors presented particle size in the range of nanometers and positive surface charge, and they were able to protect the shRNA74 against DNase. An effective and rapid uptake into the cells was observed. Silencing capacity ranged from 3% to 67% depending on the presence of DX or HA in the vector, the shRNA74 to SLN ratio, and the shRNA74 dose. Vectors prepared with HA showed to be twice more effective than those prepared with DX. Differences in the intracellular trafficking may justify the higher efficacy of the HA-prepared vectors.

A novel gene therapy vector based on hyaluronic acid and solid lipid nanoparticles for ocular diseases.

The introduction of therapeutic genes in target tissues is considered as a novel tool for the treatment of several diseases. We have developed nanoparticles consisting on SLNs, protamine (P) and hyaluronic acid (HA) as carrier for gene therapy. Stable complexes positively charged and with a particle size ranging from 240 nm to 340 nm were obtained. Transfection studies in ARPE-19 and HEK-293 cells showed the versatility of vectors to efficiently transfect cells with different division rate, widening the potential applications of SLN-based vectors. In ARPE 19cells, the incorporation of P and HA induced almost a 7-fold increase in the transfection capacity of SLNs. The CD44 inhibition studies suggested the participation of this receptor in the internalization of the vectors in this cell line. The intracellular disposition of DNA showed that the HA is able to modulate the high degree of condensation of DNA due to the protamine inside the cells; an important fact, if the vector is uptaken via non-degradative endocytosis. Besides, the therapeutic plasmid which encodes the protein retinoschisin was employed achieving a positive transfection in ARPE-19 cells, showing a promising application of this new non-viral system for the treatment of X-linked juvenile retinoschisis by gene therapy.