Acid Degradable Cationic Galactose-Based Hyperbranched Polymers as Nanotherapeutic Vehicles for Epidermal Growth Factor Receptor (EGFR) Knockdown in Cervical Carcinoma

Abstract

Strong signaling cascades derived from upregulation and overexpression of growth factors such as the EGF-family (epidermal growth factors) have been crucially related to cancer pathogenesis. Gene silencing techniques to modulate the expression of oncogenes and tumor suppresor genes are a strategy that shows great promise for cancer management but still faces some limitations in the design of biocompatible and effective vectors. In this study, we synthesized, by reversible addition-fragmentation chain transfer (RAFT) polymerization, several acid degradable galactose-based hyperbranched cationic polymers with varying molecular weights (10 to 20 kDa) and compositions with 2-lactobioamidoethyl methacrylamide [LAEMA] and 2-aminoethyl methacrylamide hydrochloride [AEMA] at different ratios (2.0, 1.0, and 0.5). These polymers were then evaluated for their ability to enhance Epidermal Growth Factor Receptor (EGFR) knockdown in cervical carcinoma. All the polymer constructs have enhanced capabilities to condensate siRNA (small interfering RNA), showing low toxicity at higher LAEMA:AEMA ratios (1.0 and 2.0). Western blot assays were conducted to quantify the EGFR expression of each treatment group demonstrating superior gene knockdown efficiency for the polymers having a LAEMA:AEMA ratio of 2.0 than the lower ratio counterparts; while maintaining low toxicity levels. Gene silencing of EGFR of up to 60% was achieved with acid degradable polymers having 10 kDa molecular weight and a LAEMA:AEMA ratio of 2.0. The superior stability of the polyplexes under physiological conditions and the low cytotoxicity observed in the 48 h post-transfection demonstrated the high potential of these acid degradable galactose-based hyperbranched cationic polymers for EGFR silencing treatment applications at the clinical level.

Tumor Microenvironment-Regulated Redox Responsive Cationic Galactose-Based Hyperbranched Polymers for siRNA Delivery

“…Cationic glycopolymers have a superior capability to be used as gene carriers as the protection of siRNA in the physiological environment can be achieved by forming stable polyplexes via electrostatic interactions, and the cytotoxicity of the polymer system can be reduced by sugar residues. , The serum stability of these polyplexes has also been enhanced , as the glyco-unit has a stealth property, which extends the lifetime of polyplexes by preventing aggregation. Furthermore, the target gene silencing efficiency can be increased by designing branched polymer structures as the latter is known to have better transfection efficiencies in comparison to their linear analogs …”

“…Another advantage of having a hyperbranched structure is towards the facile preparation of “smart” and responsive siRNA delivery systems. Biocompatible and efficient in vitro siRNA carriers were easily prepared by utilizing an acid cleavable cross-linker. , Redox-responsive carriers had been prepared for gene therapy; thus, in this study, we optimized, modulated, and prepared a redox-responsive galactose-based system and investigated its potency in siRNA delivery.…”

“…From our previous study, 60% EGFR silencing in HeLa cells was achieved safely in vitro by using 10 kDa acid-degradable cationic galactose-based hyperbranched polymer . Based on those promising results, we decided to study and improve further our hyperbranched glycopolymer for siRNA delivery.…”

Glycomacromolecules: Addressing challenges in drug delivery and therapeutic development

“…The effects of monomer distribution on cytotoxicity were explored, with polyplexes constructed using diblock copolymers displaying higher levels of cellular toxicity than the analogous statistical copolymers. In a subsequent study, 104 hyperbranched polymers constructed using these monomer units, combined with an acid-sensitive crosslinker, were demonstrated to enable enhanced silencing of the EFGR gene whilst maintaining ~80-100% levels of cell viability 48 h after transfection. In related work by the same group, 105 poly(glycidyl methacrylate) scaffolds were decorated with ethanolamine and a lactobionic acid derived aminosaccharide in differing ratios.…”

Synthesis and functionalization of hyperbranched polymers for targeted drug delivery

“…These units can be chosen to be responsive to one or multiple stimuli (e.g. pH, [19][20][21][22][23] temperature, [24][25][26][27] redox, [28][29][30] light, [31][32][33][34][35] enzyme [36,37]) to induce a change in conformation of the polymer chain or its degradation to trigger drug release. [38] Their globular three-dimensional structures lead to the formation of internal cavities that can be used to encapsulate small-molecule drugs (less than 900 g mol -1 ), e.g.…”