Chitosan-based nanoconjugate for safe and effective delivery of docetaxel to cancer cells: An explorative study

Docetaxel-tethered di-Carboxylic Acid Derivatised Fullerenes: A Promising Drug Delivery Approach for Breast Cancer

Docetaxel (DTX) has become widely accepted as a first-line treatment for metastatic breast cancer; however, the frequent development of resistance provides challenges in treating the disease.C60 fullerene introduces a unique molecular form of carbon, exhibiting attractive chemical and physical properties. Our study aimed to develop dicarboxylic acid-derivatized C60 fullerenes as a novel DTX delivery carrier. This study investigated the potential of water-soluble fullerenes to deliver the anti-cancer drug DTX through a hydrophilic linker. The synthesis was carried out using the Prato reaction. The spectroscopic analysis confirmed the successful conjugation of DTX molecules over fullerenes. The particle size of nanoconjugate was reported to be 122.13 ± 1.63 nm with a conjugation efficiency of 76.7 ± 0.14%. The designed conjugate offers pH-dependent release with significantly less plasma pH, ensuring maximum release at the target site. In-vitro cell viability studies demonstrated the enhanced cytotoxic nature of the developed nanoconjugate compared to DTX. These synthesized nanoscaffolds were highly compatible with erythrocytes, indicating the safer intravenous route administration. Pharmacokinetic studies confirmed the higher bioavailability (~ 6 times) and decreased drug clearance from the system vis-à-vis plain drug. The histological studies reveal that nanoconjugate-treated tumour cells exhibit similar morphology to normal cells. Therefore, it was concluded that this developed formulation would be a valuable option for clinical use.

A Small Sugar Molecule with Huge Potential in Targeted Cancer Therapy

The number of cancer-related diseases is still growing. Despite the availability of a large number of anticancer drugs, the ideal drug is still being sought that would be effective, selective, and overcome the effect of multidrug resistance. Therefore, researchers are still looking for ways to improve the properties of already-used chemotherapeutics. One of the possibilities is the development of targeted therapies. The use of prodrugs that release the bioactive substance only under the influence of factors characteristic of the tumor microenvironment makes it possible to deliver the drug precisely to the cancer cells. Obtaining such compounds is possible by coupling a therapeutic agent with a ligand targeting receptors, to which the attached ligand shows affinity and is overexpressed in cancer cells. Another way is to encapsulate the drug in a carrier that is stable in physiological conditions and sensitive to conditions of the tumor microenvironment. Such a carrier can be directed by attaching to it a ligand recognized by receptors typical of tumor cells. Sugars seem to be ideal ligands for obtaining prodrugs targeted at receptors overexpressed in cancer cells. They can also be ligands modifying polymers' drug carriers. Furthermore, polysaccharides can act as selective nanocarriers for numerous chemotherapeutics. The proof of this thesis is the huge number of papers devoted to their use for modification or targeted transport of anticancer compounds. In this work, selected examples of broad-defined sugars application for improving the properties of both already-used drugs and substances exhibiting anticancer activity are presented.

Improvement of Biocatalytic Properties and Cytotoxic Activity of L-Asparaginase from Rhodospirillum rubrum by Conjugation with Chitosan-Based Cationic Polyelectrolytes

L-asparaginases (L-ASNases, EC 3.5.1.1) are a family of enzymes that are widely used for the treatment of lymphoblastic leukemias. L-ASNase from Rhodospirillum rubrum (RrA) has a low molecular weight, low glutaminase activity, and low immunogenicity, making it a promising enzyme for antitumor drug development. In our work, the complex formation and covalent conjugation of the enzyme with synthetic or natural polycationic polymers was studied. Among non-covalent polyelectrolyte complexes (PEC), polyethyleneimine (PEI) yielded the highest effect on RrA, increasing its activity by 30%. The RrA-PEI complex had increased stability to trypsinolysis, with an inactivation constant decrease up to 10-fold compared to that of the native enzyme. The covalent conjugation of RrA with chitosan-PEI, chitosan-polyethylene glycol (chitosan-PEG), and chitosan-glycol resulted in an increase in the specific activity of L-asparagine (up to 30%). RrA-chitosan-PEG demonstrated dramatically (by 60%) increased cytotoxic activity for human chronic myeloma leukemia K562 cells in comparison to the native enzyme. The antiproliferative activity of RrA and its conjugates was significantly higher (up to 50%) than for that of the commercially available EcA at the same concentration. The results of this study demonstrated that RrA conjugates with polycations can become a promising strategy for antitumor drug development.