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Self-organized environment-sensitive inulin–doxorubicin conjugate with a selective cytotoxic effect towards cancer cells

An inulin-based random copolymer bearing high dose doxorubicin (18.45% on a weight basis), INU-EDA-P,C-DOXO, was prepared by coupling doxorubicin with inulin though a citraconylamide bridge used as a pH sensitive spacer. A further conjugation with pentynoic acid via an amidic bond led to the hydrophobization of the copolymer which allows the acquisition of a self-assembling ability at low concentration (0.33 mg mL−1) combining both Π–Π stacking and London interactions. Drug release studies were carried out at different pH demonstrating a remarkable pH dependency, where the maximum release rate was observed at pH mimicking cancer tissue and lysosomal environments. Besides, by measuring ζ-potential variations as a function of the pH, INU-EDA-P,C-DOXO proved capable of undergoing charge reversal at acidic pH, changing its physicochemical and biological behavior. In vitro tests with cancer (MDA-MB 231) and normal (HB-2) breast cells were carried out to verify the conjugate aptitude to follow different routes to enter cells depending on the microenvironment. This finding was supported by quantitative up-take studies, which revealed that INU-EDA-P,C-DOXO released doxorubicin before entering cancer cells, as the entire copolymer diffused across normal cell membranes without relevant modifications.

Multi-Functional Nanogels for Tumor Targeting and Redox-Sensitive Drug and siRNA Delivery

(1) Background: A new family of nanosystems able to discern between normal and tumor cells and to release a therapeutic agent in controlled way were synthetized by e-beam irradiation. This technique permits to obtain biocompatible, sterile, carboxyl-functionalized polyvinylpyrrolidone (PVP-co-acrylic acid) nanogels (NGs); (2) Methods: Here, we performed a targeting strategy based on the recognition of over-expressed proteins on tumor cells, like the folate receptor. The selective targeting was demonstrated by co-culture studies and flow cytometry analysis, using folate conjugated NGs. Moreover, nanoparticles were conjugated to a chemotherapeutic drug or to a pro-apoptotic siRNA through a glutathione sensitive spacer, in order to obtain a controlled release mechanism, specific for cancer cells. The drug efficiency was tested on tumor and healthy cells by flow cytometric analysis, confocal and epifluorescence microscopy and cytotoxicity assay; the siRNA effect was investigated by RNAi experiment; (3) Results: The data obtained showed that the use of NGs permits a faster cargo release in cancer cells, in response to high cytosolic glutathione level, also improving their efficacy; (4) Conclusion: The possibility of releasing biological molecules in a controlled way and to recognize a specific tumor target allows overcoming the typical limits of the classic cancer therapy.

Polyaminoacid–doxorubicin prodrug micelles as highly selective therapeutics for targeted cancer therapy

An amphiphilic copolymer carrying high-dose doxorubicin (21% on a weight basis), PHEA–EDA–P,C–Doxo, was prepared by coupling doxorubicin with a biocompatible polyaminoacid through a pH-sensitive spacer. Additional derivatization with 4-pentynoic acid endows it with self-assembling properties by means of π–π stacking. These micelles can be triggered to promptly release drug in lysosomes (∼40% in 12 h) through pH-dependent micelle hydrolysis after uptake. In vitro tests on co-cultures of cancer (MDA-MB 231) and normal (HB-2) breast cells proved that the conjugate was selectively internalized into the former rather than normal cells, exploiting the caveolae-dependent endocytosis pathway, explaining the selective cytotoxic effect toward cancer cells. Intracellular trafficking study of MDA-MB 231 showed that the delivery of the endocytosed drug occurs through the direct fusion of caveosomes with late lysosomes, triggering a massive release in the cytoplasm, bringing about cell death. Dose-effectiveness and mechanistic data indicate that PHEA–EDA–P,C–Doxo is endowed with a distinctive combination of selectivity and pharmacological potency (EC50 13 μM, Emax = 77% and EC50 > 25 μM, Emax = 21% for cancer and healthy cells respectively) that makes it an excellent candidate for future preclinical studies.

Tissue Dissociation and Primary Cells Isolation Using Recombinant Collagenases Class I and II

Collagenases class I (Col G) and class II (Col H) currently available for tissue dissociation are produced from Clostridium histolyticum (human pathogen) strains. In the processes of extraction of the cells from the tissue, combined activity of both classes of enzymes is required. CI and CII are complementary in degrading collagen. ABIEL recently produced the collagenase class I and II using the recombinant DNA technologies (PCT WO 2011/073925 A9). The enzymes were produced in E. coli and purified by affinity chromatography. The method of production adopted allows absolute control of the final composition of these enzymes, as well as their stability, purity, activity, absence of toxicity and higher reproducibility of batches of collagenase. The two collagenases produced separately have been used in conjunction according to precise proportions to dissociate calvaria and liver of the BALB/c mouse and bovine hoof. The analysis carried out on all isolated cell populations suggest that the cells maintain the structural and functional integrity of specific tissues/organs originating. Recombinant Col G and Col H enzymes represent a promising tool for tissue dissociation.

Functionalization of nanoparticles in specific targeting and mechanism release

The development of various nanotechnologies have provided a new field of research, which allows the manipulation of molecular components of matter and covers a vast array of nanodevices. The “smart” multifunctional nanostructures should work as customizable, targeted drug-delivery vehicles capable of carrying large doses of therapeutic agents into malignant cells. Some nanomedical approaches are based on the use of functionalized nanoparticles (NPs), not only to reduce toxicity and side effects of drugs but, also in potential the biological barriers crossing on, such as: the blood–brain barrier, different cellular compartments, including the nucleus. Currently, many materials are used for nanoparticle preparation, several of biological derivation, such as albumin, gelatin, phospholipids, etc.; others of chemical nature, such as various polymers, hydrogels, solid metals. Covalent and noncovalent chemical linking using different molecules have been reported for NPs surface functionalization, confer them specific properties, such as targeting ability. Based on the strategy chosen to control release (pH or redox or temperature sensitive NPs), different drugs are linked to NPs by adsorption, incorporation, or chemical binding. Use of smart nanocarriers can be a successful approach to overcome the limits of drug delivery.

A novel enzyme blend for efficient tissue dissociation and primary cells isolation

Tissue dissociation/primary cell isolation and cell harvesting are principal appli- cations for enzymes in tissue culture research and cell biology studies. The goal of a cell isolation procedure is to maximize the yield of functionally viable dissoci- ated cells. Among the parameters which affect the outcome of any particular dissociating procedure there are enzyme(s) used and related impurities presents in crude enzyme preparation. ABIEL srl recently produced the recombinant collagenase class I (Col G) and II (Col H) from Clostridium histolyticum (PCT WO 2011/073925 A9). The enzymes were produced in Escherichia coli and purified by affinity chromatography. The method of production adopted allows absolute control of the final composition of these enzymes, as well as their stability, purity, activity, absence of toxicity and higher reproducibility of batches. The two collagenases produced separately have been used in conjunction according to precise proportions to dissociate calvaria, liver, pancreas, retina of the BALB/c mouse; and bovine hoof. The analyses carried out on all isolated cell populations suggest that the cells maintain the structural and functional integrity of specific tissues/organs originating. Recombinant Col G and Col H enzymes produced by ABIEL are promising in the context of the tissue/cells dissociation, with the aim to make innovation in the fields of tissue engineering and transplantation medicine.