Nanodrugs based on co-delivery strategies to combat cisplatin resistance

Cisplatin (CDDP), as a broad-spectrum anticancer drug, is able to bind to DNA and inhibit cell division. Despite the widespread use of cisplatin since its discovery, cisplatin resistance developed during prolonged chemotherapy, similar to other small molecule chemotherapeutic agents, severely limits its clinical application. Cisplatin resistance in cancer cells is mainly caused by three reasons: DNA repair, decreased cisplatin uptake/increased efflux, and cisplatin inactivation. In earlier combination therapies, the emergence of multidrug resistance (MDR) in cancer cells prevented the achievement of the desired therapeutic effect even with the accurate combination of two chemotherapeutic drugs. Therefore, combination therapy using nanocarriers for co-delivery of drugs is considered to be ideal for alleviating cisplatin resistance and reducing cisplatin-related toxicity in cancer cells. This article provides an overview of the design of cisplatin nano-drugs used to combat cancer cell resistance, elucidates the mechanisms of action of cisplatin and the pathways through which cancer cells develop resistance, and finally discusses the design of drugs and related carriers that can synergistically reduce cancer resistance when combined with cisplatin.

Co-delivery of Cisplatin(IV) and Capecitabine as an Effective and Non-toxic Cancer Treatment

A strategy for preparing composite micelles (CM) containing both cisplatin(IV) [CisPt(IV)] prodrug and capecitabine using a co-assembly method is described in this study. The CM are capable of an effective release of the anticancer drug cisplatin(II) [CisPt(II)] and capecitabine via acid hydrolysis once they are internalized by cancer cells. Moreover, the CM display a synergistic effect in vitro and the combination therapy in the micellar dosage form leads to reduced systemic toxicity and enhanced antitumor efficacy in vivo.

Stimuli-Responsive Therapeutic Metallodrugs

The success of platinum-based anticancer agents has motivated the exploration of novel metal-based drugs for several decades, whereas problems such as drug-resistance and systemic toxicity hampered their clinical applications and efficacy. Stimuli-responsiveness of some metal complexes offers a good opportunity for designing site-specific prodrugs to maximize the therapeutic efficacy and minimize the side effect of metallodrugs. This review presents a comprehensive and up-to-date overview on the therapeutic stimuli-responsive metallodrugs that have appeared in the past two decades, where stimuli such as redox, pH, enzyme, light, temperature, and so forth were involved. The compounds are classified into three major categories based on the nature of stimuli, that is, endo-stimuli-responsive metallodrugs, exo-stimuli-responsive metallodrugs, and dual-stimuli-responsive metallodrugs. Representative examples of each type are discussed in terms of structure, response mechanism, and potential medical applications. In the end, future opportunities and challenges in this field are tentatively proposed. With diverse metal complexes being introduced, the foci of this review are pointed to platinum and ruthenium complexes.

A conveniently synthesized Pt (IV) conjugated alginate nanoparticle with ligand self-shielded property for targeting treatment of hepatic carcinoma

The clinical translation remains a major challenge for platinum drug loaded nanoparticle due to the complexity of composition and preparation. Here we employed only three ingredients to prepare Pt (IV) prodrug-loaded ligand-induced self-assembled nanoparticles (GA-ALG@Pt NPs) via facile one-pot route for liver tumor treatment. GA-ALG@Pt NPs were found equipped with intelligently ligand self-shielded property in which the internal GA could be induced to expose by initial cellular recognition, resulting in strengthened cellular uptake (20%-30%) and prolonged blood circulation time (3.43 times). Appreciable tumor targeting ability (2 times) and especially tumor selectivity (2.5 times) were obtained. Glutathione-triggered release of therapeutic agent generated satisfactory antitumor effect. Bio-safety is also a distinguishing feature of GA-ALG@Pt NPs that greatly relief the nephrotoxicity and systematic toxicity of cisplatin. This conveniently synthesized nanoparticle processes superior targeting capacity and biosecurity, supplying an effective approach to translational cancer therapy in the future.

A novel mixed polymeric micelle for co-delivery of paclitaxel and retinoic acid and overcoming multidrug resistance: synthesis, characterization, cytotoxicity, and pharmacokinetic evaluation

In the current study, retinoic acid (RA) was conjugated to Pluronic F127 (PF127) through an esterification process. Mixed micelles were formed with tocopheryl polyethylene glycol 1000 (TPGS) for co-delivery of paclitaxel (PTX) and RA to the cancer cells. Mixed micelles of RA-PF127 and TPGS in different weight ratios (10:0, 7:3, 5:5, 3:7, 0:10 w/w) were prepared and physicochemical properties including, particle size, zeta potential, critical micelle concentration (CMC), drug loading content, entrapment efficiency, drug release, cellular uptake and in vitro cytotoxicity, were investigated in details. Furthermore, the pharmacokinetics of PTX-loaded optimized mixed micelles were evaluated in Sprague-Dawley rats and compared with Stragen^® (PTX in Cremophor EL^®). Particle sizes and zeta potentials of the drug-loaded micelles were in the range of 102.6-223.5 nm and -5.3 to -9.6 mV, respectively. The 7:3 and 5:5 micellar combinations had lower CMC values (0.034-0.042 mg/mL) than 0:10 (0.124 mg/mL). The entrapment efficiencies of 10:0, 7:3, and 5:5 were 53.4 ± 9.3%, 61.3 ± 0.5%, and 78.7 ± 1.66%, respectively. The release rates of PTX from 7:3 and 5:5 mixed micelles were significantly slower than other formulations. Cytotoxicity assay demonstrated increased cytotoxic activity of PTX-loaded mixed micelles compared to free PTX. The V_d and t_1/2ß of PTX-loaded RA-PF127/TPGS (7:3) were increased by 2.61- and 1.27-fold, respectively, while the plasma area under the curve (AUC) of the micelles was 2.03-fold lower than those of Stragen^®. Therefore, these novel mixed micelles could be effectively used for delivery of PTX and RA to the cancer cells. Moreover, TPGS as part of micelle composition could enhance the therapeutic effect of PTX and reduce side effects.

Retinol initiated poly(lactide)s: stability upon polymerization and nanoparticle preparation

The synthesis of retinol initiated polylactide (PLA) by ring opening polymerization (ROP) of l-lactide via in situ calcium alkoxide formation with all-trans-retinol and Ca[N(SiMe₃)₂]₂(THF)₂ is described.

Nanoprodrug of retinoic acid-modified paclitaxel

A nanoprodrug with high content (75%) and increased water solubility of paclitaxel was prepared from retinoic acid-modified paclitaxel.

Metal-containing and related polymers for biomedical applications

A survey of the most recent progress in the biomedical applications of metal-containing polymers is given. Due to the unique optical, electrochemical, and magnetic properties, at least 30 different metal elements, most of them transition metals, are introduced into polymeric frameworks for interactions with biology-relevant substrates via various means. Inspired by the advance of metal-containing small molecular drugs and promoted by the great progress in polymer chemistry, metal-containing polymers have gained momentum during recent decades. According to their different applications, this review summarizes the following biomedical applications: (1) metal-containing polymers as drug delivery vehicles; (2) metal-containing polymeric drugs and biocides, including antimicrobial and antiviral agents, anticancer drugs, photodynamic therapy agents, radiotherapy agents and biocides; (3) metal-containing polymers as biosensors, and (4) metal-containing polymers in bioimaging.

VP, Dasgupta S, Bose K JC, Mukherjee S, Linert W, Moi SC. Benzimidazole based Pt(ii) complexes with better normal cell viability than cisplatin: synthesis, substitution behavior, cytotoxicity, DNA binding and DFT study

Water soluble Pt(ii) complexes with higher viability towards normal cells and comparable cytotoxicity to cancer cells as compared to cisplatin.

Incorporation of cisplatin into the metal–organic frameworks UiO66-NH2 and UiO66 – encapsulation vs. conjugation

This work demonstrates synthetic strategies for the incorporation of an anticancer drug, cisplatin, and a Pt(iv) cisplatin prodrug into two zirconium-based metal–organic-frameworks (MOFs): UiO66 and UiO66-NH₂.

Biodegradable polymer–platinum drug conjugates to overcome platinum drug resistance

Biodegradable polymers with pendent pair-wised carboxylic acids but lacking sulfur were used to chelate oxaliplatin prodrug which self-assembled into micelles in water for drug delivery.

Noncovalent interaction-assisted polymeric micelles for controlled drug delivery

Various individual or synergistic noncovalent interactions were employed to mediate polymeric micelles for controlled drug delivery.