A polymer-(tandem drugs) conjugate for enhanced cancer treatment

Dual-responsive supramolecular photodynamic nanomedicine with activatable immunomodulation for enhanced antitumor therapy

A major challenge facing photodynamic therapy (PDT) is that the activity of the immune-induced infiltrating CD8+ T cells is subject to the regulatory T lymphocytes (Tregs), leaving the tumor at risk of recurrence and metastasis after the initial ablation. To augment the antitumor response and reprogram the immunosuppressive tumor microenvironment (TME), a supramolecular photodynamic nanoparticle (DACss) is constructed by the host-guest interaction between demethylcantharidin-conjugated β-cyclodextrin (DMC-CD) and amantadine-terminated disulfide-conjugated FFVLGGGC peptide with chlorin e6 decoration (Ad-ss-pep-Ce6) to achieve intelligent delivery of photosensitizer and immunomodulator for breast cancer treatment. The acid-labile β-carboxamide bond of DMC-CD is hydrolyzed in response to the acidic TME, resulting in the localized release of DMC and subsequent inhibition of Tregs. The guest molecule Ad-ss-pep-Ce6 can be cleaved by a high level of intracellular GSH, reducing photosensitizer toxicity and increasing photosensitizer retention in the tumor. With a significant increase in the CTL/Treg ratio, the combination of Ce6-based PDT and DMC-mediated immunomodulation adequately achieved spatiotemporal regulation and remodeling of the TME, as well as improved primary tumor and in situ lung metastasis suppression with the aid of PD-1 antibody.

Reactive oxygen species-responsive polyprodrug micelles deliver cell cycle regulators for chemosensitization

Combination chemotherapy is a common strategy to enhance treatment efficacy and avoid multidrug resistance (MDR) in clinical practice. However, it is difficult to ensure the co-enrichment and reasonable ratio of synergistic drugs in the lesion site after intravenous administration. Integrating synergistic drugs into a nanocarrier can improve drug stability, targeting, drug loading, and importantly, ensure that synergistic drugs work at one destination. This study uses 10-hydroxycamptothecin (HCPT) to construct a polymeric prodrug micelle, and the demethylcantharidin (DMC) is proportionally encapsulated within the micelle. Triggered by reactive oxygen species (ROS), HCPT and DMC were released simultaneously from the co-delivery platform in tumor cells. DMC promotes abnormal cell division by inhibiting the synthesis of the cell cycle checkpoint kinase Protein phosphatase 2A (PP2A), leading to increased cell vulnerability to DNA damage, disordered replication, and death. The co-delivery platform exhibited satisfactory biosafety and antitumor efficacy in vivo. The proposed co-delivery platform may provide a valuable reference for the translation of clinical combination chemotherapy regimens into nano-drug delivery systems.

Recent Advances of Platinum-Based Anticancer Complexes in Combinational Multimodal Therapy

Platinum drugs with manifest therapeutic effects are widely used, but their systemic toxicity and the drug resistance acquired by cancer cells limit their clinical applications. Thus, the exploration on appropriate methods and strategies to overcome the limitations of traditional platinum drugs becomes extremely necessary. Combination therapy of platinum drugs can inhibit tumor growth and metastasis in an additive or synergistic manner, and can potentially reduce the systemic toxicity of platinum drugs and overcome platinum-resistance. This review summarizes the various modalities and current progress in platinum-based combination therapy. The synthetic strategies and therapeutic effects of some platinum-based anticancer complexes in the combination of platinum drugs with gene editing, ROS-based therapy, thermal therapy, immunotherapy, biological modelling, photoactivation, supramolecular self-assembly and imaging modality are briefly described. Their potential challenges and prospects are also discussed. It is hoped that this review will inspire researchers to have more ideas for the future development of highly effective platinum-based anti-cancer complexes.

Emerging platinum(IV) prodrug nanotherapeutics: A new epoch for platinum-based cancer therapy

Owing to the unique DNA damaging cytotoxicity, platinum (Pt)-based chemotherapy has long been the first-line choice for clinical oncology. Unfortunately, Pt drugs are restricted by the severe dose-dependent toxicity and drug resistance. Correspondingly, Pt(IV) prodrugs are developed with the aim to improve the antitumor performance of Pt drugs. However, as "free" molecules, Pt(IV) prodrugs are still subject to unsatisfactory in vivo destiny and antitumor efficacy. Recently, Pt(IV) prodrug nanotherapeutics, inheriting both the merits of Pt(IV) prodrugs and nanotherapeutics, have emerged and demonstrated the promise to address the underexploited dilemma of Pt-based cancer therapy. Herein, we summarize the latest fronts of emerging Pt(IV) prodrug nanotherapeutics. First, the basic outlines of Pt(IV) prodrug nanotherapeutics are overviewed. Afterwards, how versatile Pt(IV) prodrug nanotherapeutics overcome the multiple biological barriers of antitumor drug delivery is introduced in detail. Moreover, advanced combination therapies based on multimodal Pt(IV) prodrug nanotherapeutics are discussed with special emphasis on the synergistic mechanisms. Finally, prospects and challenges of Pt(IV) prodrug nanotherapeutics for future clinical translation are spotlighted.

Verteporfin-loaded supramolecular micelles for enhanced cisplatin-based chemotherapy via autophagy inhibition

Cisplatin (CDDP) is one of the most successful chemotherapeutic agents for cancer therapy. However, CDDP can activate pro-survival autophagy, which inhibits the therapeutic efficacy of CDDP. Herein, autophagy inhibitor verteporfin (VTPF) is integrated into CDDP-conjugated micelles to address this issue. The CDDP-conjugated micelles are prepared by host-guest interaction of zwitterionic poly(2-(methacryloyloxy)ethyl phosphorylcholine)-co-poly(2-(methacryloyloxy)ethyl adamantane-1-carboxylate) (P(MPC-co-MAd)) and CDDP conjugated β-cyclodextrin (CD-CDDP). VTPF is then physically encapsulated into the supramolecular micelles by hydrophobic interaction. Due to the zwitterionic corona of the supramolecular micelles, the micelles are stable in different media. CDDP and VTPF could be released in a reductive environment. CDDP-activated autophagy could be inhibited by VTPF, which is fully characterized by western blot, fluorescence imaging, and transmission electron microscopy (TEM). Moreover, the outstanding therapeutic efficacy of CDDP and VTPF co-loaded micelles is validated both in vitro and in vivo. This research not only provides a new strategy to fabricate CDDP delivery systems by supramolecular self-assembly, but also presents an innovative way to enhance cisplatin-based chemotherapy via autophagy inhibition.

Organic/Inorganic Self-Assembled Hybrid Nano-Architectures for Cancer Therapy Applications

Since the conceptualization of nanomedicine, numerous nanostructure-mediated drug formulations have progressed into clinical trials for treating cancer. However, recent clinical trial results indicate such kind of drug formulations has a limited improvement on the antitumor efficacy. This is due to the biological barriers associated with those formulations, for example, circulation stability, extravasation efficiency in tumor, tumor penetration ability, and developed multi-drug resistance. When employing for nanomedicine formulations, pristine organic-based and inorganic-based nanostructures have their own limitations. Accordingly, organic/inorganic (O/I) hybrids have been developed to integrate the merits of both, and to minimize their intrinsic drawbacks. In this context, the recent development in O/I hybrids resulting from a self-assembly strategy will be introduced. Through such a strategy, organic and inorganic building blocks can be self-assembled via either chemical covalent bonds or physical interactions. Based on the self-assemble procedure, the hybridization of four organic building blocks including liposomes, micelles, dendrimers, and polymeric nanocapsules with five functional inorganic nanoparticles comprising gold nanostructures, magnetic nanoparticles, carbon-based materials, quantum dots, and silica nanoparticles will be highlighted. The recent progress of these O/I hybrids in advanced modalities for combating cancer, such as, therapeutic agent delivery, photothermal therapy, photodynamic therapy, and immunotherapy will be systematically reviewed.

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.

Nanomedicine to target multidrug resistant tumors

Nanomedicine employs nanotechnologies to develop innovative applications, and more specifically nano-objects in the field of human health, through exploitation of the physical, chemical and biological properties of materials at the nanoscale. The use of nanovehicles capable of transporting and releasing the active therapeutic payload into target cells, particularly in the case of cancer or inflammatory diseases, can also enhance diagnosis. Therefore, nanomedicines improve the benefit/risk ratio of drugs by increasing their bioavailability, selectivity, and efficacy in the target tissue, while reducing the necessary doses and hence diminishing untoward toxicity to healthy tissues. Overcoming multidrug resistance (MDR) to antitumor agents is a central goal of cancer research and therapeutics, making it possible to treat these diseases more accurately and effectively. The adaptability of nanomedicines e.g. modulation of their components, surface functionalization, encapsulation of various active therapeutics as well as the possibility of combining several treatments using a single nanoparticle platform, are characteristics which are perfectly poised to address classical chemoresistance, a major obstacle towards curative cancer therapy. In this review, we discuss an assortment of nanomedicines along with those that should be developed in order to surmount cancer MDR; these include exosomes, natural compounds, lipid nanocapsules, prodrug self-assemblies, and gold nanoparticles.

Tailoring the Chemical Modification of Chitosan Hydrogels to Fine-Tune the Release of a Synergistic Combination of Chemotherapeutics

Combination chemotherapy with a defined ratio and sequence of drug release is a clinically established and effective route to treat advanced solid tumors. In this context, a growing body of literature demonstrates the potential of hydrogels constructed with chemically modified polysaccharides as depots for controlled release of chemotherapeutics. Identifying the appropriate modification in terms of physicochemical properties of the functional group and its degree of substitution (χ) to achieve the desired release profile for multiple drugs is, however, a complex multivariate problem. To address this issue, we have developed a computational toolbox that models the migration of a drug pair through a hydrated network of polysaccharide chains modified with hydrophobic moieties. In this study, we chose doxorubicin (DOX) and Gemcitabine (GEM) as model drugs, as their synergistic effect against breast cancer has been thoroughly investigated, and chitosan as the model polymer. Our model describes how the modification of chitosan chains with acetyl, butanoyl, and heptanoyl moieties at different values χ governs both the structure of the hydrogel network and drug migration through it. Our experimental data confirm the in silico predictions for both single- and dual-drug release and, most notably, the counterintuitive inversion of release vs χ that occurs when switching from a single- to a dual-drug system. Consensus between predicted and experimental data indicates that acetyl modifications (χ = 32-42%) and butanoyl modifications (χ = 19-24%) provide synergistic GEM/DOX release molar ratios (i.e., 5-10). Collectively, these results demonstrate the potential of this model in guiding the design of chemotherapeutic hydrogels to combat cancer.

Sandwich-Like Fibers/Sponge Composite Combining Chemotherapy and Hemostasis for Efficient Postoperative Prevention of Tumor Recurrence and Metastasis

Intraoperative bleeding is an essential factor leading to the earliest recurrence and tumor metastasis frequently seen after resection of solid tumors. Local drug delivery implants show the unique advantages on postoperative cancer therapy. Herein, a sandwich-like cisplatin-loaded fibers/sponge composite (CFSC) combining chemotherapy and hemostasis is constructed. The obtained implantable CFSC is able to simultaneously stop bleeding and absorb disseminated tumor cells after tumor resection. More importantly, sustained released cisplatin can kill local residual tumor cells as well as those concentrated in the CFSC, which significantly inhibits local tumor recurrence and distant tumor metastasis on the subcutaneous postoperative recurrence model and metastasis models. This dual functional implant strategy with low toxicity to healthy organs may inspire new aspects for efficient postoperative cancer therapy.

Preparation of PGA-PAE-Micelles for Enhanced Antitumor Efficacy of Cisplatin

Poly-γ-l-glutamic acid (PGA) is an outstanding drug carrier candidate owning to its excellent biodegradability and biocompatibility. The PGA carrier may shield toxic drugs from the body and enable the delivery of poorly soluble or unstable drugs and thereby minimize the side effects and improve drug efficacy. However, the limitation of PGA as a drug carrier is low drug loading efficiency (DLE), which is usually below 30%. In this study, we reported a chemical modification method using l-phenylalanine ethyl ester (PAE). PGA-PAE construct was amphiphilic, which could form micelles in aqueous solution. Cisplatin (CDDP), a commonly used chemotherapy drug whose side effect is well-known, was used as a model molecule to test the drug-loading efficiency of PGA-PAE. In this paper, two sizes of CDDP-loaded PGA-PAE micelles (M(Pt)-1 and M(Pt)-2) were prepared, the average diameter of M(Pt)-1 was 106 ± 6 nm and M(Pt)-2 was 210 ± 9 nm. The DLE of M(Pt)-1 and M(Pt)-2 was 52.8 ± 2.2 and 55.8 ± 1.2%, respectively. Both exhibited excellent biocompatibility, stability, and drug-retaining capability in physiological condition. The in vitro accumulative drug-releasing profile, IC₅₀ for different tumor cell lines HeLa, A549, and HCCC9810, and in vivo pharmacokinetics were similar between these two micelles; however, M(Pt)-1 showed higher tumor tissue retention and longer efficient cancer cell internalization time (up to 20 d). Our results suggested PGA-PAE micelle carriers reduced the toxicity of CDDP and its size at around 100 nm was the better for CDDP high-efficacy.

Dual Drug Backboned Shattering Polymeric Theranostic Nanomedicine for Synergistic Eradication of Patient-Derived Lung Cancer

Most of the current nanoparticle-based therapeutics worldwide failing in clinical trials face three major challenges: (i) lack of an optimum drug delivery platform with precise composition, (ii) lack of a method of directly monitoring the fate of a specific drug rather than using any other labelling molecules as a compromise, and (iii) lack of reliable cancer models with high fidelity for drug screen and evaluation. Here, starting from a PP2A inhibitor demethylcantharidin (DMC) and cisplatin, the design of a dual sensitive dual drug backboned shattering polymer (DDBSP) with exact composition at a fixed DMC/Pt ratio for precise nanomedicine is shown. DDBSP self-assembled nanoparticle (DD-NP) can be triggered intracellularly to break down in a chain-shattering manner to release the dual drugs payload. Moreover, DD-NP with extremely high Pt heavy metal content in the polymer chain can directly track the drug itself via Pt-based drug-mediated computer tomography and ICP-MS both in vitro and in vivo. Finally, DD-NP is used to eradicate the tumor burden on a high-fidelity patient-derived lung cancer model for the first time.

Self-assembling prodrugs

Covalent modification of therapeutic compounds is a clinically proven strategy to devise prodrugs with enhanced treatment efficacies. This prodrug strategy relies on the modified drugs that possess advantageous pharmacokinetic properties and administration routes over their parent drug. Self-assembling prodrugs represent an emerging class of therapeutic agents capable of spontaneously associating into well-defined supramolecular nanostructures in aqueous solutions. The self-assembly of prodrugs expands the functional space of conventional prodrug design, affording a possible pathway to more effective therapies as the assembled nanostructure possesses distinct physicochemical properties and interaction potentials that can be tailored to specific administration routes and disease treatment. In this review, we will discuss the various types of self-assembling prodrugs in development, providing an overview of the methods used to control their structure and function and, ultimately, our perspective on their current and future potential.

Mesoporous silica nanoparticles with lactose-mediated targeting effect to deliver platinum(iv) prodrug for liver cancer therapy

A mesoporous silica nanoparticle system with a lactose-mediated targeting effect was demonstrated to deliver a platinum(iv) prodrug for liver cancer therapy.

Enhancing Therapeutic Efficacy of Cisplatin by Blocking DNA Damage Repair

Self-repair of nuclear DNA damage is the most known reason that leads to drug resistance of cancer tissue and limited therapeutic efficacy of anticancer drugs. Inhibition of protein phosphatase 2A (PP2A) would block DNA damage-induced defense of cancer cells to suppress DNA repair for enhanced cancer treatment. Here, we combined a PP2A inhibitor LB (4-(3-carboxy-7-oxa-bicyclo[2.2.1]heptane-2-carbonyl) piperazine-1-carboxylic acid tert-butyl ester) and the DNA damage chemotherapeutic drug cisplatin through a simple physical superposition. The two drugs administrated at a ratio of 1:1 exhibited an optional synergistic antitumor efficacy in vitro and in vivo. LB was demonstrated to specifically activate the protein kinase B (Akt) and mitogen-activated protein kinases (MAPK) signaling pathways by PP2A inhibition to overcome cell cycle arrest caused by cisplatin-induced DNA damage.

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.

Simultaneously Photo-Cleavable and Activatable Prodrug-Backboned Block Copolymer Micelles for Precise Anticancer Drug Delivery

A simultaneously photo-cleavable and activatable prodrug-backboned block copolymer (BCP) micelle strategy is demonstrated. Without light treatment, the micelles stay silent and inactivated, being biocompatible to normal tissues. Concurrent chain cleavage of BCP micelles and the activation of Pt(IV) prodrug could be temporally and spatially triggered by UV or even visible light for precise anticancer drug delivery.

Reduction/pH dual-responsive nano-prodrug micelles for controlled drug delivery

We provided a facile strategy to fabricate reduction/pH dual-responsive nano-prodrug micelles for controlled drug delivery.

Multifunctional single-drug loaded nanoparticles for enhanced cancer treatment with low toxicity in vivo

After nanoparticles internalized, active oxaliplatin(ii) and DMC can be released upon UVA and intracellular stimulation, exhibiting enhanced anti-cancer efficacy.

Advances in drug delivery system for platinum agents based combination therapy

Platinum-based anticancer agents are widely used as first-line drugs in cancer chemotherapy for various solid tumors. However, great side effects and occurrence of resistance remain as the major drawbacks for almost all the platinum drugs developed. To conquer these problems, new strategies should be adopted for platinum drug based chemotherapy. Modern nanotechnology has been widely employed in the delivery of various therapeutics and diagnostic. It provides the possibility of targeted delivery of a certain anticancer drug to the tumor site, which could minimize toxicity and optimize the drug efficacy. Here, in this review, we focused on the recent progress in polymer based drug delivery systems for platinum-based combination therapy.

A dextran-platinum(iv) conjugate as a reduction-responsive carrier for triggered drug release

Reduction-responsive nano-carriers have been confirmed to be promising for intracellular drug delivery. To develop multifunctional polymer-based drug delivery system, a novel dextran-Pt(iv) conjugate was synthesized by conjugating Pt(iv) to the side chains of the hydrophilic dextran and used for doxorubicin (DOX) delivery. Pt(iv) conjugation could change the hydrophilicity of dextran, leading to the self-assembly of dextran-Pt(iv) conjugates with different morphologies. Pt(iv) segments served as the key components in assembly formation and as the antitumor prodrug. Under a reductive environment, Pt(iv) was found to be reduced to its active Pt(ii) form and cleaved from dextran, shifting the hydrophilic-hydrophobic balance of the dextran-Pt(iv) conjugate. The collapse of the assembly structure due to the partial or complete recovery of the hydrophilicity of dextran led to triggered release of DOX. The DOX-loaded dextran-Pt(iv) conjugate obtained by combining the released hydrophobic DOX and recovered hydrophilic Pt(ii), was found to be very effective as an antitumor agent as demonstrated in in vitro cytotoxicity evaluations. This DOX-loaded dextran-Pt(iv) conjugate system provided a new strategy to trigger the release of hydrophobic and hydrophilic drugs at the same time via single reduction-responsive control to provide an enhanced anti-tumor effect.

Recent Advances in Platinum (IV) Complex-Based Delivery Systems to Improve Platinum (II) Anticancer Therapy

Cisplatin and its platinum (Pt) (II) derivatives play a key role in the fight against various human cancers such as testicular, ovarian, head and neck, lung tumors. However, their application in clinic is limited due to dose- dependent toxicities and acquired drug resistances, which have prompted extensive research effort toward the development of more effective Pt (II) delivery strategies. The synthesis of Pt (IV) complex is one such an area of intense research fields, which involves their in vivo conversion into active Pt (II) molecules under the reducing intracellular environment, and has demonstrated encouraging preclinical and clinical outcomes. Compared with Pt (II) complexes, Pt (IV) complexes not only exhibit an increased stability and reduced side effects, but also facilitate the intravenous-to-oral switch in cancer chemotherapy. The overview briefly analyzes statuses of Pt (II) complex that are in clinical use, and then focuses on the development of Pt (IV) complexes. Finally, recent advances in Pt (IV) complexes in combination with nanocarriers are highlighted, addressing the shortcomings of Pt (IV) complexes, such as their instability in blood and irreversibly binding to plasma proteins and nonspecific distribution, and taking advantage of passive and active targeting effect to improve Pt (II) anticancer therapy.

Cisplatin-loaded polymeric nanoparticles: characterization and potential exploitation for the treatment of non-small cell lung carcinoma

Cisplatin-loaded poly(l-glutamic acid)-g-methoxy poly(ethylene glycol 5K) nanoparticles (CDDP-NPs) were characterized and exploited for the treatment of non-small cell lung carcinoma (NSCLC). In vitro metabolism experiments showed that a glutamic acid 5-mPEG ester [CH3O(CH2CH2O)nGlu] was generated when the poly(l-glutamic acid)-g-methoxy poly(ethylene glycol 5K) (PLG-g-mPEG5K) was incubated with HeLa cells. This suggests that the poly(glutamic acid) backbone of the PLG-g-mPEG5K is biodegradable. Furthermore, the size of the CDDP-NPs in an aqueous solution was affected by varying the pH (5.0-8.0) and their degradation rate was dependent on temperature. The CDDP-NPs could also bind to the model nucleotide 2'-deoxyguanosine 5'-monophosphate, indicating a biological activity similar to cisplatin. The CDDP-NPs showed a significantly lower peak renal platinum concentration after a single systemic administration when compared to free cisplatin. In vivo experiments with a Lewis lung carcinoma (LLC) model showed that the CDDP-NPs suppressed the growth of tumors. In addition, LLC tumor-bearing mice treated with the CDDP-NPs (5mg/kg cisplatin eq.) showed much longer survival rates (median survival time: 51days) as compared with mice treated with free cisplatin (median survival time: 18days), due to the acceptable antitumor efficacy and low systemic toxicity of CDDP-NPs. These results suggest that the CDDP-NPs may be successfully applied to the treatment of NSCLC.

Targeting and microenvironment-responsive lipid nanocarrier for the enhancement of tumor cell recognition and therapeutic efficiency

Poor recognition and penetration of chemotherapeutic agents in solid tumors have been recognized as one of the major challenges limiting the efficacy of cancer therapies. Folic acid and tumor microenvironment-sensitive polypeptide (TMSP) co-modified lipid-nanocarrier (F/TMSP-NLC) are successfully formulated in response to the overexpression of folate receptor (FR) and the upregulation of matrix metalloproteinase-2 (MMP-2) in tumor microenvironment. The F/TMSP-NLC accumulates in tumor via the enhanced permeability and retention (EPR) effect, and folate moiety binds selectively to the FR once it reaches the tumor. In addition, cell-penetrating peptide (CPP)-penetrating activity is initiated by MMP-2 protease-oversecretion tumor. The specificity and efficacy of the co-modified nanocarriers to tumor are investigated in KB, HT-1080 and A549 cells in vitro. Multivalent interactions induce the enhancement of cancer cell recognition and internalization, which subsequently result in cancer cell apoptosis or death. The F/TMSP-NLC shows long-circulation effect, high accumulation in tumor, strong tumor inhibition, increased apoptotic indices, and negligible toxicity in vivo. In conclusion, the present nanocarrier modified with both TMSP and folic acid is a potential drug delivery system for tumor cell recognition and therapy, implying that using more than one target from the pool of tumor-stroma interactions is profoundly beneficial to therapeutic approaches.

Facile synthesis of magnetic carboxymethylcellulose nanocarriers for pH-responsive delivery of doxorubicin

Multi-functional magnetic carboxymethylcellulose nanocarriers were successfully synthesized via a facile solvothermal method.

A polymer–(multifunctional single-drug) conjugate for combination therapy

A single-drug integrating three different drug functions (platinum, azidyl radical and DMC) and two types of therapies (chemotherapy and radiation therapy) was synthesized and attached onto a carrier to prepare a polymer–(multifunctional single-drug) conjugate.

Synergistic antitumor effects of doxorubicin-loaded carboxymethyl cellulose nanoparticle in combination with endostar for effective treatment of non-small-cell lung cancer

The multi-modal combination therapy is proved powerful and successful to enhance the antitumor efficacy in clinics as compared with single therapy modes. In this study, the potential of combining chemotherapy with antiangiogenic therapy for the treatment of non-small-cell lung cancer is explored. Towards this aim, OEGylated carboxymethyl cellulose-(2-(2-(2-methoxyethoxy)ethoxy)methyl)oxirane (CMC-ME2MO) is prepared by treating CMC with ME2MO in the alkaline aqueous solution, and used to efficiently carry doxorubicin (DOX) with high drug-loading content (16.64%) and encapsulation efficiency (99.78%). As compared to free DOX, the resulting nanoparticles show not only the favorable stability in vitro but also the prolonged blood circulation, improved safety and tolerability, optimized biodistribution, reduced systemic toxicity, and enhanced antitumor efficacy in vivo, indicates a potential utility in cancer chemotherapy. Furthermore, the combination of the DOX-loaded polysaccharide nanoparticles and antiangiogenic drug endostar provides synergistic effects of chemotherapy and antiangiogenic therapy, which shows the highest efficiency in tumor suppression. The combination approach of the DOX-containing nanomedicine and endostar for efficient treatment of non-small-cell lung cancer is first proposed to demonstrate the synergistic therapeutic effect. This synergistic combination proves to be a promising therapeutic regimen in cancer therapy and holds great potential for clinical application.

Micro- and nanotechnologies for intracellular delivery

The majority of drugs and biomolecules need to be delivered into cells to be effective. However, the cell membranes, a biological barrier, strictly resist drugs or biomolecules entering cells, resulting in significantly reduced intracellular delivery efficiency. To overcome this barrier, a variety of intracellular delivery approaches including chemical and physical ways have been developed in recent years. In this review, the focus is on summarizing the nanomaterial routes involved in making use of a collection of receptors for the targeted delivery of drugs and biomolecules and the physical ways of applying micro- and nanotechnologies for high-throughput intracellular delivery.

Overcoming tumor resistance to cisplatin through micelle-mediated combination chemotherapy

The main obstacles to cancer therapy are the inability to target cancer cells and the acquired drug resistance after a period of chemotherapy. Reduced drug uptake and DNA repair are the two main mechanisms involved in cisplatin resistance. In the present investigation, canthaplatin, a Pt(iv) pro-drug of cisplatin and a protein phosphatase 2A (PP2A) inhibitor (4-(3-carboxy-7-oxa-bicyclo[2.2.1]heptane-2-carbonyl)piperazine-1-carboxylic acid tert-butyl ester), was designed and delivered using PEG-b-PLGA micelles for combination chemotherapy. Polymer/canthaplatin micelles facilitated the delivery of the drug into cancer cells through endocytosis and diminished DNA repair by PP2A inhibition, resulting in enhanced anti-tumor efficiency and excellent reversal ability of tumor resistance to cisplatin both in vitro and in vivo. Additionally, the polymer/canthaplatin micelles could prolong drug residence in the blood and decrease the side effects when compared to cisplatin.

Acid-triggered drug release from micelles based on amphiphilic oligo(ethylene glycol)–doxorubicin alternative copolymers

We prepared pH-sensitive amphiphilic oligo(ethylene glycol)–doxorubicin alternative conjugates for the controlled release of doxorubicin.