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Although chemotherapy is the most common method in clinical therapeutics with a straightforward mechanism, conventional anti-tumor drugs are still almost incapable of preventing the occurrence of tumor metastasis. In this study, we developed a multi-functional drug delivery system EINP@DOX consisting of a tea-derived polyphenol EGCG, iron ions and DOX. The system integrated the functions of tumor inhibition, diagnosis and metastasis prevention to achieve a systematic tumor treatment. The nanoscale size of EINP@DOX facilitated its accumulation in tumor tissues by means of the enhanced permeability and retention (EPR) effect, and it was then transferred to endosomes. The weakly acidic microenvironment in the endosomes of the tumor cells could destroy the coordination structure of EINP@DOX to realize the release of DOX for tumor therapy. Furthermore, the dissociative EGCG played the role of an adjuvant to restrain EMT and down-regulate the MMP levels, which could prevent the occurrence of tumor metastasis. Meanwhile, iron ions as superior magnetic resonance imaging (MRI) contrast agents provided visual evidence for the accurate location of EINP@DOX. In vitro and in vivo studies demonstrated that EINP@DOX showed a remarkable performance in tumor diagnosis and excellent therapeutic efficacy, inhibiting the metastasis of tumor cells effectively at the same time.

In recent decades, drug self-delivery systems (DSDSs) have appeared with extraordinary superiority for cancer therapy while realizing intracellular delivery without supererogatory drug carriers. Here, we have designed and programmed a novel self-delivery system to realize tumor targeting therapy. The amphiphilic proapoptotic peptide KLAKLAKKLAKLAKGCK(Fmoc) 2 (KLA) was used to form a self-assembled structure (KD) by encapsulating the hydrophobic anticarcinogen doxorubicin (DOX). Then, tumor recognizing hyaluronic acid (HA) was coated on the surface of KD to obtain a tumor targeting self-delivery system (KDH). The protective layer of HA could protect the therapeutic agents from being inactivated during blood circulation, and further specifically recognize tumor cells by the CD44 receptor after KDH had located the tumor regions. Additionally, hyaluronidase (HAase) overexpressed in the endosome of tumor cells could degrade the protective layer of HA and accelerate the liberation of KLA and DOX. The proapoptotic peptide KLA had the ability to locate mitochondria and induce mitochondrial dysfunction; meanwhile the anticarcinogen DOX diffused to the nuclei to inhibit the growth of tumor cells. Both in vitro and in vivo studies identified that our self-delivery system KDH possessed precise tumor targeting, and exhibited fantastic antitumor efficacy as well as negligible side effects.

In recent decades, diverse drug delivery systems (DDS) constructed by self-assembly of dendritic peptides have shown advantages and improvable potential for cancer treatment. Here, an arginine-enriched dendritic amphiphilic chimeric peptide CRRK(RRCG(Fmoc)) 2 containing multiple thiol groups is programmed to form drug-loaded nano-micelles by self-assembly. With a rational design, the branched hydrophobic groups (Fmoc) of the peptides provide a strong hydrophobic force to prevent the drug from premature release, and the reduction-sensitive disulfide linkages formed between contiguous peptides can control drug release under reducing stimulation. As expected, specific to multidrug resistance (MDR) tumor cells, the arginine-enriched peptide/drug (PD) nano-micelles show accurate nuclear localization ability to prevent the drug being pumped by P-glycoprotein (P-gp) in vitro, as well as exhibiting satisfactory efficacy for MDR tumor treatment in vivo. This design successfully realizes stimuli-responsive drug release aimed at MDR tumor cells via an ingenious sequence arrangement., (© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The polycarbonate copolymer poly(trimethylene carbonate-co-5,5-dimethyl trimethylene carbonate) (P(TMC-co-DTC)) was synthesized by the polymerization of trimethylene carbonate (TMC) and 5,5-dimethyl trimethylene carbonate (DTC) using tin (II) 2-ethylhexanoate [Sn(Oct)(2)] as a catalyst. In vitro degradation tests indicated this polycarbonate copolymer degraded slowly in phosphate buffer saline solution (PBS, 0.1 mol/L, at 37°C). Magnetic polymer microspheres (MMC-PC-M) generated from the P(TMC-co-DTC) copolymer and containing Fe(3)O(4) magnetic ultrafine powders and an anticancer drug, mitomycin C (MMC) were prepared by a solvent evaporation technique. These anticancer magnetic polycarbonate microspheres showed strong magnetic responsiveness and high MMC loading capacity. In vitro drug release studies indicated that these microspheres sustained steady release rates of MMC in PBS. In vitro cytotoxicity assays demonstrated the microspheres were strongly inhibitory to human hepatic carcinoma (Bel-7204) cells. In vivo site-specific therapy in nude mice with human hepatic carcinoma indicated that the microspheres possessed markedly high antitumor activity against human hepatic carcinoma (Bel-7204)., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Objective: The specific expression of transferrin receptor can represent a diagnostic tool or therapeutic target in solid tumors expressing this antigen. Herein, the human transferrin receptor monoclonal antibody (T9) was investigated as a tumor-targeting group for active targeted-drug delivery systems. Materials and methods: A tumor-targeted conjugate T9-TNF was synthesized by the attachment of both human transferrin receptor monoclonal antibody (T9) as a tumor-targeting group and human tumor necrosis factor-α (TNF) as an anti-cancer drug to two terminated hydroxyl groups of poly(ethylene glycol). Subsequently, a solvent evaporation technique was adopted to produce anti-cancer magnetic polymer microspheres T9-TNF-PC-M containing T9-TNF and Fe3O4 magnetic ultrafine powders (M) using poly(trimethylene carbonate-co-5,5-dimethyl trimethylene carbonate) (PC, P(TMC-co-DTC)) as a polymeric carrier. Results and discussion: These magnetic polycarbonate microspheres possessed a steady TNF release rate in phosphate buffer saline solution, strong magnetic responsiveness and high T9-TNF loading capacity. In vitro cytotoxicity assays demonstrated the microspheres T9-TNF-PC-M and conjugate T9-TNF were strongly inhibitory to the human hepatic carcinoma (Bel-7204) cells. In vivo site-specific therapy in nude mice with human hepatic carcinoma indicated that the microspheres T9-TNF-PC-M and conjugate T9-TNF possessed markedly higher anti-tumor activity against Bel-7204 in mice than that of TNF. Conclusions: These results indicated that the magnetic polycarbonate microspheres were suitable as the potential-targeted treatment for hepatic carcinoma therapeutics. [ABSTRACT FROM AUTHOR]

ABSTRACT Polycarbonate microspheres TT-PC containing tetanus toxoid vaccine (TT) were prepared by the modified water-in-oil-in-water (W/O/W) solvent evaporation technique, using poly(trimethylene carbonate- co−5,5-dimethyl trimethylene carbonate) (P(TMC- co-DTC), or PC) as a polymeric carrier. TT release studies showed that the microspheres sustained a steady release rate of TT in the phosphate buffer saline solution (0.1 mol L−1, pH 7.4) in vitro for 60 days. In vivo cytotoxicity assays demonstrated that the polycarbonate microspheres had low toxicity and high safety in vivo in guinea pigs. Immunity and inoculation tests indicated that the TT-PC microspheres acted as an immunological adjuvant in vivo in guinea pigs. In guinea pigs attacked with an active tetanus toxoid, an injection of the TT-PC microspheres with a single-dose and booster vaccination induced high levels of antitoxin efficiencies in the blood serum, showing good immunoprotection. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2014, 131, 40048. [ABSTRACT FROM AUTHOR]

Purpose: The aim was to investigate anticancer drug-loaded poly(carbonate-ester) nanospheres as potential drug delivery systems for cancer therapy. Methods: Functional poly(carbonate-ester) copolymers (HPCP-SD) were synthesized by the incorporation of sulfadiazine as the tumor-targeting groups to hydroxyl groups of poly(carbonate-ester) copolymers. Two types of anticancer drug-loaded poly(carbonate-ester) nanospheres I and II were further prepared by dialysis method and high-voltage electrostatic field-assisted atomization, respectively, using HPCP-SD as polymeric carriers. These carriers and anticancer drug-loaded nanospheres were characterized, and their properties in vitro and in vivo were evaluated. Results: These anticancer drug-loaded poly(carbonate-ester) nanospheres had steady drug release rates and good controlled release properties. Moreover, anticancer drug-loaded poly(carbonate-ester) nanospheres II had faster drug release rates than those of anticancer drug-loaded nanospheres I. These anticancer drug-loaded nanospheres possessed lower cytotoxicity to HEK 293 cells and exhibited obviously higher anticancer efficiencies to the HeLa tumor cells than that of 5-fluorouracil. Anticancer drug-loaded nanospheres I possessed lower cytotoxicity to HEK 293 cells and higher anticancer activity to HeLa cells than those of anticancer drug-loaded nanospheres II. Conclusions: These anticancer drug-loaded poly(carbonate-ester) nanospheres showed the potential as drug delivery systems for cancer therapy. [ABSTRACT FROM AUTHOR]

The article discusses a study which examined the synthesis of a series of copolymers through the ring-opening bulk polymerization of ε-caprolactone (CL) and 2-phenyl-5,5-bis(hydroxymethyl) trimethylene carbonate (PTC) containing tin(II) 2-ethyhexanoate. It notes the use of a palladium/carbonate catalyst for the further reduction of copolymers. Results of the study showed that CL and PTC copolymerization was nonideal and that the reactivity ratio of CL was higher than that of PTC.