Research and Development in Release Systems for Gene Therapy

It constitutes the most recent line of research of the group and started with the main researcher of a Thematic Project, which brought together integrated strategies for the Treatment of Tuberculosis, with the main focus on Vaccination and Gene Therapy. The development of this line is consolidating the group in the area of ​​release systems based on liquid crystals, adding knowledge and working techniques. This line opened a new research area, which is the development of delivery systems and carrier molecules for peptide drugs, aligning the group’s research with future trends for the therapies of the most varied pathologies, which at the moment, have numerous limitations of delivery and administration. The delivery systems developed in this line are also being studied for topical application of peptide drugs for the treatment of cutaneous pathologies and topical administration of active ingredients in cosmetics. More recently, the group has been pioneering research on topical and systemic release systems for carrying and releasing siRNA in silencing gene therapy aimed at treating skin diseases such as psoriasis, vitiligo and skin cancer.

 

Development of liposomal systems for the release of alpha-glucosidase as a proposal for Pompe disease therapy

Pompe’s disease is caused by the deficiency of the lysosomal enzyme α-glycosidase acid (GAA) resulting in the accumulation of glycogen in the cells. The main tissues affected are cardiac, smooth and skeletal muscle and nervous. The clinical spectrum comprises a child form, more severe with high morbidity and mortality, and a late form, with slower progression, which causes muscle weakness and respiratory failure. The currently available therapy consists of enzyme replacement with a recombinant enzyme and represented a significant improvement in the patients’ life expectancy. Despite this, some factors still limit its benefits, such as the low availability and absorption of the free enzyme by the target cells, not interrupting the progression of the disease. Thus, the use of nanotechnology in the development of drug delivery systems appears as an alternative to overcome the difficulties of applying the free enzyme in the bloodstream. Among the available systems, liposomes represent an advanced technology for carrying active molecules. Liposomes are biocompatible and biodegradable lipid vesicular structures that allow delivery of the agent into cells or cellular compartments. The coating of the liposomal surface with hydrophilic components, such as polyethylene glycol (PEG), significantly increases its circulation time. Furthermore, specific ligands, such as antibodies, have been incorporated into the surface of these liposomes, seeking active targeting to a target site. As a result, the use of a long-circulating liposomal carrier functionalized with the antibody to the insulin receptor may result in greater distribution of the GAA enzyme to the target tissues, decreasing the necessary therapeutic dose and overcoming the current barriers for an adequate treatment of the Pompe’s disease.

 

Nanotechnology-based Cancer Therapeutics

This proposal is based on the solid areas of expertise of the Langer group at the MIT, which are also the focus of interest of the researches conducted by the Brazilian collaborators, including: a) the investigation of the mechanism of drug release from nanoparticulate drug delivery systems; b) the development and applications of these systems for the controlled delivery of anti-cancer drugs, gene therapy and antiangiogenesis; c) investigation of magnetically responsive controlled release systems and d) targeted drug delivery and approaches to promote drug delivery across biological barriers. The research involved in this proposal is at the interface of biotechnology and materials science. A major focus is the study and development of polymeric and lipidic nanostructures to deliver drugs, particularly genetically engineered proteins, DNA and RNAi, continuously at controlled rates for prolonged periods of time. Work is in progress in the following areas: -Investigating the mechanism of release from polymeric and lipid delivery systems with concomitant microstructural analysis and mathematical modeling. -Studying applications of these systems including the development of effective long-term delivery systems and also target formulation for, anti-cancer drugs, growth factors, gene therapy agents (especially siRNA) and vaccines.

 

Photodynamic Therapy for skin cancer

This research field started in 1996 with a also innovative approach: the development of delivery systems and vehicles that optimize the release of photosensitizers and their precursors in the skin, a theme that was then considered an important gap for the consolidation of Therapy. The research carried out provided the development of experimental models in vitro and in vivo for the study of formulations for PDT, drug delivery systems (liposomes, liquid crystals and microemulsions), exploration of the proposal of prodrugs (acid derivatives esters) as 5-aminolevulinic for PDT. So far, the research developed in this field through several publications in journals of great impact in the field of Pharmacy and, more importantly, several citations in publications by the most renowned groups from abroad working in the field of Photodynamic Therapy. It can be said that the group has become a reference in the pharmacotechnical development of formulations and drug administration techniques in Photodynamic Therapy and photodiagnosis. The newest activity of the group started in 2004, with the approach of nitric oxide releasing compounds for the Topical Photodynamic Therapy of Skin Cancer, an innovative approach in relation to the topical application of these compounds and, also for the development of delivery systems that optimize the release of these compounds in the skin. Intellectual property was also generated through two patent filings at the National Institute of Intellectual Property (PI n. 0206723-4 and PI n. 0206724-2). This line continues to rise in the group, which sees exciting possibilities for scientific, technological development and clinical application for the therapy of a disease with a high incidence in the world population, skin cancer.

 

Liquid crystalline nanodispersions for topical delivery of siRNA

Recent advances in exploring physiological processes at the molecular level and in the complete characterization of the human genome have brought great hope for the transformation of nucleic acids into new therapeutic agents. The potential use of RNA fragments (small interfering RNA, siRNA) in gene therapy has attracted great attention as a new approach for the treatment of chronic and severe diseases. siRNAs specifically induce post-transcriptional silencing of gene expression, in a process called RNA interference (RNAi). However, obstacles in in vivo administration and delivery compromise the potential for clinical use of siRNAs, making the development of delivery systems a key factor in transforming siRNAs into new therapeutic agents. At the same time, the topical release of siRNAs appears as a promising alternative for the treatment of skin pathologies. In this context, the objective of this project is to develop a delivery system based on Nanotechnology for the release of interfering RNAs (siRNAs) in the skin, aiming to enable gene therapy as a new approach for the treatment of cutaneous pathologies of genetic cause. In the last two decades, liquid-crystalline systems have attracted great attention due to their applications in several areas. The nanodispersion of liquid crystal particles, especially those of non lamellar phase as cubic and hexagonal phase, has shown interesting characteristics for a topical delivery system.

 

Crystalline liquid geleification systems in situ after subcutaneous and intratumoral administration for sustained siRNA release in skin cancer therapy

The RNA interference mechanism is an event of gene repression through the degradation of messenger RNA. This way, it is possible to eliminate the expression of a certain gene, making siRNA a promising therapy for the treatment of several serious diseases, such as cancer. However, for its effective therapeutic application it is necessary to develop delivery systems capable of releasing siRNA in target cells, promoting their cell internalization and preventing its degradation. For the treatment of cancer, where there is high cell proliferation and the effect of siRNA is for a few days, it is interesting to develop systems that promote sustained release of siRNA. A system that has this characteristic are liquid formulations based on lipids or amphilyls that form liquid crystals that are transformed in situ into liquid crystalline gels by self-assembling mechanisms, in the case caused by the absorption of water from the biological environment of the administration site. (subcutaneous or intratumoral). Preliminary results from our research group using formulations based on structural lipids (monolein) and complexing cationic components of siRNA (oleylamine and polyethyleneimine) showed that they are capable of promoting sustained release after gelation, as well as forming complexes with siRNA, being still biocompatible and biodegradable. In this context, the objective of the present project is to develop a delivery system based on precursor liquid formulations for in situ formation of crystalline liquid phase gels after subcutaneous and intratumoral administration, aiming to make gene therapy viable as a new approach for the treatment of severe skin pathologies, where local drug administration is an advantage. The specific objectives of this project include: Standardization of the process for obtaining sterile precursor formulations capable of gelling in situ for parenteral use.