A Pt(iv)-mediated polymer architecture for facile and stimuli-responsive intracellular gene silencing with chemotherapy

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.

CD47KO/CRT dual-bioengineered cell membrane-coated nanovaccine combined with anti-PD-L1 antibody for boosting tumor immunotherapy

Tumor vaccines trigger tumor-specific immune responses to prevent or treat tumors by activating the hosts' immune systems, and therefore, these vaccines have potential clinical applications. However, the low immunogenicity of the tumor antigen itself and the low efficiency of the vaccine delivery system hinder the efficacy of tumor vaccines that cannot produce high-efficiency and long-lasting antitumor immune effects. Here, we constructed a nanovaccine by integrating CD47KO/CRT dual-bioengineered B16F10 cancer cell membranes and the unmethylated cytosine-phosphate-guanine (CpG) adjuvant. Hyperbranched PEI25k was used to load unmethylated cytosine-phosphate-guanine (CpG) through electrostatic adsorption to prepare PEI25k/CpG nanoparticles (PEI25k/CpG-NPs). CD47KO/CRT dual-bioengineered cells were obtained by CRISPR-Cas9 gene editing technology, followed by the cell surface translocation of calreticulin (CRT) to induce immunogenic cell death (ICD) in vitro. Finally, the extracted cell membranes were coextruded with PEI25k/CpG-NPs to construct the CD47KO/CRT dual-bioengineered cancer cell membrane-coated nanoparticles (DBE@CCNPs). DBE@CCNPs could promote endocytosis of antigens and adjuvants in murine bone marrow derived dendritic cells (BMDCs) and induce their maturation and antigen cross-presentation. To avoid immune checkpoint molecule-induced T cell dysfunction, the immune checkpoint inhibitor, the anti-PD-L1 antibody, was introduced to boost tumor immunotherapy through a combination with the DBE@CCNPs nanovaccine. This combination therapy strategy can significantly alleviate tumor growth and may open up a potential strategy for clinical tumor immunotherapy.

Phenylboronic acid-based core-shell drug delivery platform clasping 1,3-dicarbonyl compounds by a coordinate interaction

Along with the successful commercialization of chemotherapeutics, such as doxorubicin and paclitaxel, numerous natural compounds have been investigated for clinical applications. Recently, curcumin (CUR), a natural compound with various therapeutic effects, has attracted attention for cancer immunotherapy. Most chemotherapeutics, however, have poor water solubility due to their hydrophobicity, which makes them less suited to biomedical applications; CUR is no exception because of its low bioavailability and extremely high hydrophobicity. In the present study, we developed an easy but effective strategy using the interaction between the 1,3-dicarbonyl groups of drugs and phenylboronic acid (PBA) to solubilize hydrophobic drugs. First, we verified the coordinate interaction between 1,3-dicarbonyl and PBA using 3,5-heptanedione as a model compound, followed by CUR as a model drug. A PBA-grafted hydrophilic polymer was used to form a nanoconstruct by coordination bonding with CUR, which then made direct administration of the nanoparticles possible. The nanoconstruct exhibited remarkable loading capability, uniform size, colloidal stability, and pH-responsive drug release, attributed to the formation of core-shell nanoconstructs by coordinate interaction. The therapeutic nanoconstructs successfully showed both chemotherapeutic and anti-PD-L1 anticancer effects in cellular and animal models. Furthermore, we demonstrated the applicability of this technique to other 1,3-dicarbonyl compounds. Overall, our findings suggest a facile, but expandable strategy by applying the coordinate interaction between 1,3-dicarbonyl and PBA, which enables high drug loading and stimuli-responsive drug release.

Platinum-based chemotherapy via nanocarriers and co-delivery of multiple drugs

Platinum-based anticancer drugs can inhibit the growth of cancer cells by disrupting DNA replication, which makes them widely applicable in clinics for treating tumors and cancers. However, owing to the intrinsic or acquired drug resistance and severe side effects caused in the treatment, their successful clinical applications have been limited. Various strategies have been used to address these challenges. Nanocarriers have been used for platinum drug delivery because they can be effectively deposited in tumor tissues to reduce the damage to normal organs for an enhanced permeability and retention (EPR) effect. Furthermore, for synergizing the function of platinum-based drugs with different mechanisms to decrease the toxicities, multicomponent chemotherapy has become an imperative strategy in clinical cancer treatments. This review aims to introduce the mechanisms of action and limitations of platinum-based drugs in clinics, followed by providing the current advancement of nanocarriers including lipids, polymers, dendrimers, micelles and albumin for platinum drug delivery in cancer treatments. In addition, multicomponent chemotherapy based on platinum drugs is introduced in detail. Finally, the prospects of multicomponent chemotherapy for cancer treatment are discussed as well.

H2O2-responsive nano-prodrug for podophyllotoxin delivery

The tumor microenvironment is different from that of normal tissue; therefore, the development of a prodrug that retains its efficacy in the tumor microenvironment can be useful in enhancing the anticancer properties of podophyllotoxin. An innovative podophyllotoxin prodrug (POD-PEG) was designed by linking podophyllotoxin to poly(ethylene glycol)(n) monomethacrylate with a H2O2-responsive oxalate ester bond. POD-PEG can self-assemble into stable nanoparticles (POD-PEG NPs). In vitro experiments demonstrated that the POD-PEG NPs can be activated by hydrogen peroxide resulting in podophyllotoxin release and are highly toxic against colon carcinoma CT26 cells. In vivo biodistribution studies demonstrate that PEGylated POD-PEG NPs are capable of prolonging blood circulation. Intravenous injection of POD-PEG NPs into CT26 tumor-bearing Balb/c mice resulted in a significantly enhanced therapeutic efficacy against tumors, with no significant systemic toxicity. Therefore, this H2O2-responsive prodrug delivery system exhibits good biosafety and provides a novel strategy for the development of drug delivery systems.

Zinc ion coordination significantly improved the transfection efficiency of low molecular weight polyethylenimine

A zinc ion coordination-contained polycationic gene delivery system.