Cationic Galactose-Conjugated Copolymers for Epidermal Growth Factor (EGFR) Knockdown in Cervical Adenocarcinoma

Targeted downregulation of MYC mediated by a highly efficient lactobionic acid-based glycoplex to enhance chemosensitivity in human hepatocellular carcinoma cells

The chemosensitization of tumor cells by gene therapy represents a promising strategy for hepatocellular carcinoma (HCC) treatment. In this regard, HCC-specific and highly efficient gene delivery nanocarriers are urgently needed. For this purpose, novel lactobionic acid-based gene delivery nanosystems were developed to downregulate c-MYC expression and sensitize tumor cells to low concentration of sorafenib (SF). A library of tailor-made cationic glycopolymers, based on poly(2-aminoethyl methacrylate hydrochloride) (PAMA) and poly(2-lactobionamidoethyl methacrylate) (PLAMA) were synthesized by a straightforward activators regenerated by electron transfer atom transfer radical polymerization. The nanocarriers prepared with PAMA₁₁₄-co-PLAMA₂₀ glycopolymer were the most efficient for gene delivery. These glycoplexes specifically bound to the asialoglycoprotein receptor and were internalized through the clathrin-coated pit endocytic pathway. c-MYC expression was significantly downregulated by MYC short-hairpin RNA (MYC shRNA), resulting in efficient inhibition of tumor cells proliferation and a high levels apoptosis in 2D and 3D HCC-tumor models. Moreover, c-MYC silencing increased the sensitivity of HCC cells to SF (IC₅₀ for MYC shRNA+ SF 1.9 μM compared to 6.9 μM for control shRNA + SF). Overall, the data obtained demonstrated the great potential of PAMA₁₁₄-co-PLAMA₂₀/MYC shRNA nanosystems combined with low doses of SF for the treatment of HCC.

Glycopolymers Mediate Suicide Gene Therapy in ASGPR-Expressing Hepatocellular Carcinoma Cells in Tandem with Docetaxel

Cationic glycopolymers stand out as gene delivery nanosystems due to their inherent biocompatibility and high binding affinity to the asialoglycoprotein receptor (ASGPR), a target receptor overexpressed in hepatocellular carcinoma (HCC) cells. However, their synthesis procedure remains laborious and complex, with problems of solubilization and the need for protection/deprotection steps. Here, a mini-library of well-defined poly(2-aminoethyl methacrylate hydrochloride-co-poly(2-lactobionamidoethyl methacrylate) (PAMA-co-PLAMA) glycopolymers was synthesized by activators regenerated by electron transfer (ARGET) ATRP to develop an efficient gene delivery nanosystem. The glycoplexes generated had suitable physicochemical properties and showed high ASGPR specificity and high transfection efficiency. Moreover, the HSV-TK/GCV suicide gene therapy strategy, mediated by PAMA₁₄₄-co-PLAMA₁₉-based nanocarriers, resulted in high antitumor activity in 2D and 3D culture models of HCC, which was significantly enhanced by the combination with small amounts of docetaxel. Overall, our results demonstrated the potential of primary-amine polymethacrylate-containing-glycopolymers as HCC-targeted suicide gene delivery nanosystems and highlight the importance of combined strategies for HCC treatment.

Glycopolymer-Cell-Penetrating Peptide (CPP) Conjugates for Efficient Epidermal Growth Factor Receptor (EGFR) Silencing

Overexpression of epidermal growth factor receptor (EGFR) is observed in multiple cancers such as colorectal, lung, and cervical solid tumors. Regulating the EGFR expression is an efficient strategy to manage these malignancies, and it can be achieved by using short interfering RNA (siRNA). Cell-penetrating peptides (CPPs) demonstrated an excellent capability to enhance the cellular uptake of siRNA, but high knockdown efficiencies have not been achieved due to endosomal entrapment. In this work, Schiff's base reaction was used to modify a block {P[LAEMA(2-lactobionamidoethyl methacrylamide)₃₇]-b-P[FPMA(4-formyl phenyl methacrylate)₂-st-DMA(N,N-dimethylacrylamide)₂], P2} and two statistical [P(LAEMA₂₃-st-FPMA₃) (P3) and P(LAEMA₂₅-st-FPMA₂-st-DMA₂) (P4)] aldehyde-based and galactose-based polymers, prepared via reversible addition-fragmentation chain-transfer (RAFT) polymerization. An arginine-rich peptide (ARP, KRRKRRRRRK) was used as a cell-penetrating peptide (CPP) and conjugated to the polymers via a Schiff base reaction. The resulting glycopolymer-peptide conjugates were utilized to condense the siRNA to prepare polyplexes with multivalent CPPs (MCPPs, a nanoparticle with multiple copies of the CPP) to enhance the endosomal escape. The polyplexes have different surface properties as determined by the architecture of polymers and the insertion of dimethyl amide moieties. The enhancement of cellular internalization of ARP was observed by labeling the polyplexes with fluorescein isothiocyanate (FITC)-siRNA showing a localization of polyplexes in the cytoplasm of a HeLa (cervical cancer) cell line. In the in vitro EFGR silencing study, the statistical glycopolymer-peptide (P3-P) polyplexes had superior EGFR silencing efficiency in comparison with the other polymers that were studied. Furthermore, P3-P polyplexes led to less off-targeting silencing than lipofectamine 3000. These encouraging results confirmed the potency of decorating galactose-based polymers with CPP, like ARP for their application in siRNA delivery and management of cervical carcinomas.

Tailor-made Glycopolymers via Reversible Deactivation Radical Polymerization: Design, Properties and Applications

Investigating the underlying mechanism of biological interactions using glycopolymer is becoming increasingly important owing to their unique recognition properties. The multivalent interactions between lectin and glycopolymer are significantly influenced by...

Glycomacromolecules: Addressing challenges in drug delivery and therapeutic development

Carbohydrate-based materials offer exciting opportunities for drug delivery. They present readily available, biocompatible components for the construction of macromolecular systems which can be loaded with cargo, and can enable targeting of a payload to particular cell types through carbohydrate recognition events established in biological systems. These systems can additionally be engineered to respond to environmental stimuli, enabling triggered release of payload, to encompass multiple modes of therapeutic action, or to simultaneously fulfil a secondary function such as enabling imaging of target tissue. Here, we will explore the use of glycomacromolecules to deliver therapeutic benefits to address key health challenges, and suggest future directions for development of next-generation systems.

Dual-luciferase assay and siRNA silencing for nodD1 to study the competitiveness of Bradyrhizobium diazoefficiens USDA110 in soybean nodulation

The symbiosis of soybean with Bradyrhizobium diazoefficiens USDA110, which always competes with other rhizobia in the field, is of great agronomic and environmental importance. Herein, a dual-luciferase reporter assay was utilized to monitor the dynamics of two dominant bradyrhizobia infecting roots of soybean. More explicitly, luciferase-tagged B. diazoefficiens USDA110 (USDA110-FLuc) and Bradyrhizobium elkanii USDA 94 (USDA94-RLuc) were designed, co-inoculated into soybean seeds, and observed for their colonization in root nodules by bioluminescence imaging. The results showed that USDA110-FLuc initiated infection earlier than USDA94-RLuc, but its occupancy in the nodules decreased as the plant grew. A nodulation test showed that nodD1 mutant USDA110 strains, including CRISPR engineered mutants, were less competitive than wild type. I constructed siRNAs to knockdown nodD1 at different target sites and transformed them into the bacteria. Surprisingly, although siRNAs - with 3' end target sites - were able to repress up to 65% of nodD1 expression, the profiling of total RNAs with a bioanalyzer revealed that 23S/16S-rRNA ratios of siRNA-transformed and wild type USDA110 strains were similar, but lower than that of nodD1 mutant. In short, the current work - while reporting the competitiveness of B. diazoefficiens USDA110 in early occupancy of soybean nodules and the gene nodD1 as a key determinant of this infection - gives an insight on siRNA silencing in microbes, and demonstrates a highly efficient imaging approach that could entail many new avenues for many biological research fields.

Carbohydrates: Potential Sweet Tools Against Cancer

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Cancer, one of the most devastating degenerative diseases nowadays, is one of the main targets in Medicinal Chemistry and Pharmaceutical industry. Due to the significant increase in the incidence of cancer within world population, together with the complexity of such disease, featured with a multifactorial nature, access to new drugs targeting different biological targets connected to cancer is highly necessary.

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Among the vast arsenal of compounds exhibiting antitumor activities, this review will cover the use of carbohydrate derivatives as privileged scaffolds. Their hydrophilic nature, together with their capacity of establishing selective interactions with biological receptors located on cell surface, involved in cell-to-cell communication processes, has allowed the development of an ample number of new templates useful in cancer treatment.

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Their intrinsic water solubility has allowed their use as of pro-drug carriers for accessing more efficiently the pharmaceutical targets. The preparation of glycoconjugates in which the carbohydrate is tethered to a pharmacophore has also allowed a better permeation of the drug through cellular membranes, in which selective interactions with the carbohydrate motifs are involved. In this context, the design of multivalent structures (e.g. gold nanoparticles) has been demonstrated to enhance crucial interactions with biological receptors like lectins, glycoproteins that can be involved in cancer progression.

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Moreover, the modification of the carbohydrate structural motif, by incorporation of metal complexes, or by replacing their endocyclic oxygen, or carbon atoms with heteroatoms has led to new antitumor agents.

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Such diversity of sugar-based templates with relevant antitumor activity will be covered in this review.

Hydroxyl-Rich PGMA-Based Cationic Glycopolymers for Intracellular siRNA Delivery: Biocompatibility and Effect of Sugar Decoration Degree

The ErbB family of proteins, structurally related to the epidermal growth factor receptor (EGFR), is found to be overexpressed in many cancers such as gliomas, a lung and cervical carcinomas. Gene therapy allows to modify the expression of genes like ErbB and has been a promising strategy to target oncogenes and tumor suppressor genes. In the current work, novel hydroxyl-rich poly(glycidyl methacrylate) (PGMA)-based cationic glycopolymers were designed for intracellular small interfering RNA (siRNA) delivery to silence the EGFR gene. The cationic polymers with different sugar decoration degrees (0, 9, and 33%) were synthesized by ring-opening reaction of PGMA with ethanolamine and a lactobionic acid-derived aminosaccharide (Lac-NH₂). Specific EGFR knockdown of the protein tyrosine kinase ErbB-overexpressing HeLa cells was achieved using these hydroxyl-rich polycation/siRNA complexes. Higher sugar content improved the biocompatibility of the polymers, but it also seems to decrease the EGFR knockdown capability, which should mainly be related to the surface charge of polyplexes. An optimum balance was observed with PGEL-1 (9% sugar content) formulation, achieving ∼52% knockdown efficiency as well as high cell viability. Considering the specific recognition between galactose residues and asialoglycoprotein receptor in hepatocytes, our novel PGMA-based cationic glycopolymers exhibited promising future to serve as a safe and targeting gene delivery vector to hepatoma cell line like HepG2.

Synthesis of chitosan-mimicking cationic glycopolymers by Cu(0)-LRP for efficient capture and killing of bacteria

A schematic representation of the preparation of cationic magnetic glyconanoparticles by Cu(0)-LRP to efficiently capture, kill and separate E. coli from water.

Effective and Specific Gene Silencing of Epidermal Growth Factor Receptors Mediated by Conjugated Oxaborole and Galactose-Based Polymers

Oxaborole-based polymers are stimuli-responsive materials that can reversibly interact with diols at pH values higher than their pK_a. The strong binding of the oxaborole with cis-hydroxyl groups allow rapid cross-linking of the polymer chains. In this study, we exploited this phenomenon to develop a novel delivery system for the complexation, protection, and delivery of epidermal growth factor receptors (EGFR) siRNA (small interfering RNA). Galactose and oxaborole polymers were first synthesized by the reversible addition-fragmentation chain transfer (RAFT) process, and they were found to show a robust interaction with each other via the oxaborole-diol effect, which allowed the formation of stable polyplexes with siRNA. Although complexes were successfully formed between the neutral galactose and oxaborole-based polymers, these complexes were insufficient in the protection of the siRNA. Therefore, cationic glycopolymers and oxaborole polymers were investigated showing superior complexation with siRNA and exhibiting effective gene silencing in HeLa (cervical) cancer cells, while showing low toxicity. Gene silencing of up to 60% was achieved with these new complexes in the presence and absence of serum. The excellent stability of the complexes under physiological conditions and the observed low cytotoxicity 48 h post-transfection demonstrated the high potential of this new system for gene silencing therapy application in clinics.