Chitosan nanoparticles with integrin inhibitors as potential drug delivery system for therapy and diagnostic imaging in cancer

Author(s)

Charlene Priscila Kiill

• Document type: Doctoral Thesis
• Press: Araraquara. 2016-11-23.
• Institution: Universidade Estadual Paulista (Unesp). Faculdade de Ciências Farmacêuticas. Araraquara
• Defense date: 2016-05-24
• Advisor: Maria Palmira Daflon Gremião

Abstract

Glioblastoma multiforme (GBMs) is the most invasive tumor from central nervous system (CNS) and its invasiveness is related to interaction between glycoproteins of extracellular matrix and integrins present in tumor cells. Integrins α5β1, αvβ5, e αvβ3 are overexpressed in GBMs and they could be used as target molecules in the treatment and diagnostic imaging of the tumors from CNS. The disintegrins cRGDfV, cRGDfK and vicrostatin have been studied for the treatment of GBMs because they inhibit the integrins αvβ3, αvβ5, and α5β1, and, therefore, they show potent anti˗tumor properties. However, the administration of therapeutic proteins is limited by their low stability in physiological fluids and low penetration in biological membranes. To overcome these problems, drug delivery systems have been developed and alternative route of administration, such as nasal administration, has been used. Thus, the aim of this study was the development of chitosan nanoparticles, employing factorial design, by the means of ionotropic gelification and the encapsulation of disintegrins cRGDfV e cRGDfK. The chitosan˗based drug delivery system increased the mucoadhesion, which could promote the blood˗brain barrier permeation of disintegrins cRGDfV and cRGDfK. Another strategy aimed in this work was the use of chitosan nanoparticles selected by factorial design to be modified with PEG by supramolecular interactions and also by covalent interactions with methoxy˗polyethylene glycol and maleimide˗polyethylene glycol˗hydroxisuccinimide. The modified nanoparticles by covalent interactions were functionalized through linkage of disintegrin cRGDfK on nanoparticles’ surface in order to improve the targeting of nanoparticles to tumor environment by specific interactions with the integrins overexpressed in the GBMs. Theranostic carboxymethylchitosan nanoparticles containing the contrast agent gadolinium˗diethylenetriamine˗pentaacetate˗meglumine were also developed; these nanoparticles was developed by eletrostatic interactions, and then they were modified by covalent interactions to attach the desintegrin vicrostatin on the surface of these nanoparticles. All formulations obtained were characterized by size distribution, zeta potential, scanning eletron microscopy, atomic force microscopy, nuclear magnetic resonance, differential scanning calorimetry, circular dichroism and Fourier transform infrared spectrocopy. In in vitro cytotoxicity assays using GBMS cells, it was possible to observe the differences in the cell viability when the desintegrins cRGDfV and cRGDfK were encapsuled into nanoparticles and when the desintegrin cRGDfK is on the surface of nanoparticles. The nanoparticles with cRGDfK on the surface presented a significative decrease in cell viability as compared to nanoparticles which the disintegrins are encapsulated. In the uptake and internalization assays by flow citometry and confocal microscopy, the cRGDfK attached to chitosan nanoparticles and vicrostatin attached to the theranostic carboxymethylchitosan nanoparticles showed a specific interaction with the integrins, leading to higher uptake of nanoparticles by GBMs cells, and, thus, promoting an anti˗tumor effect due to integrins inhibition. In the case of theranostic nanoparticles, an increase in uptake of gadolinium could happen and it could facilitate the diagnosis by image. The nanoparticles developed can be exploited as a platform in order to assist in the treatment and diagnosis by image of the GBMs. (AU)

• FAPESP's process: 12/10174-3 - EVALUATION OF CHITOSAN NANOPARTICLES FOR DELIVERY OF POTENTIALLY ACTIVE INTEGRINS INHIBITORS IN GLIOBLASTOMAS
• Grantee: Charlene Priscila Kiill
• Support Opportunities: Scholarships in Brazil - Doctorate