Magnetic Hydrogel with Optimally Adaptive Functions for Breast Cancer Recurrence Prevention.

Engineering biocompatible hydrogels using functional nanoparticles has attracted considerable attention because of their uniquely appealing cooperative effects that can enable multimodality imaging and treatment with improved efficacy against serious diseases. However, the effects of high-content nanoparticle dopants on the rheological properties of hydrogels frequently lead to an unsatisfactory therapeutic result, which is particularly notable in the design of magnetic hydrogel formulations for cancer therapy. Herein is reported a novel magnetic hydrogel functionalized by ferromagnetic vortex-domain iron oxide (FVIOs) with optimally adaptive functions for prevention of breast cancer recurrence. The FVIOs can perfectly incorporate into the dynamic hydrogel networks with an extremely low concentration (0.6 mg mL-1 ), 17 times lower than that of conventional superparamagnetic iron oxide nanoparticles with sufficient heating capacity. Such magnetic hydrogels exhibit high inductive heating and remarkable rheological properties simultaneously. Moreover, the self-healing, self-conformal ability, controlled release of loaded doxorubicin, biodegradation, and pH-responsiveness of the magnetic hydrogel project their efficient sustainable therapeutic ability. In vivo postoperative treatment has further demonstrated the high efficacy of FVIO-based magnetic hydrogels, as evidenced by the significant suppression of the local tumor recurrences compared to chemotherapy or hyperthermia alone. This unique magnetic hydrogel formulation with optimally adaptive functions shows strong potential in preventing relapses of various cancers.

Nanomedicine strategies for sustained, controlled and targeted treatment of cancer stem cells.

Cancer stem cells (CSCs) are original cancer cells that are of characteristics associated with normal stem cells. CSCs are toughest against various treatments and thus responsible for cancer metastasis and recurrence. Therefore, development of specific and effective treatment of CSCs plays a key role in improving survival and life quality of cancer patients, especially those in the metastatic stage. Nanomedicine strategies, which include prodrugs, micelles, liposomes and nanoparticles of biodegradable polymers, could substantially improve the therapeutic index of conventional therapeutics due to its manner of sustained, controlled and targeted delivery of high transportation efficiency across the cell membrane and low elimination by intracellular autophagy, and thus provide a practical solution to solve the problem encountered in CSCs treatment. This review gives briefly the latest information to summarize the concept, strategies, mechanisms and current status as well as future promises of nanomedicine strategies for treatment of CSCs.

Cationic liposomes induce cell necrosis through lysosomal dysfunction and late-stage autophagic flux inhibition.

AIM: The application of cationic liposomes (CLs) as nonviral vectors is hampered by their cellular toxicity. Thus we aim to investigate the mechanisms underlying the cellular toxicity of CLs. MATERIALS & METHODS: The effect of CLs on the autophagic flux, autophagosome-lysosome fusion, lysosome membrane permeabilization and cell necrosis of liver cells was investigated. RESULTS & CONCLUSION: Our results reveal a novel mechanism of CL-induced cell necrosis involving the induction of lysosome membrane permeabilization and late-stage autophagic flux inhibition that resulted in cytoplasmic release of cathepsin B, mitochondrial dysfunction and reactive oxygen species production, which are the key mediators of cell necrosis. Our study is important for revealing the cellular toxicity of CLs and designing safer gene delivery systems.

CD20 Antibody-Conjugated Immunoliposomes for Targeted Chemotherapy of Melanoma Cancer Initiating Cells.

Cancer initiating cells (CIC) are tumorigenic cancer cells that have properties similar to normal stem cells. CD20 is a phenotype of melanoma CIC that is responsible for melanoma drug resistance. Vincristine (VCR) is commonly used in melanoma therapy; however, it has been found ineffective against CIC. To target CD20+ melanoma CIC, we prepared VCR-containing immunoliposomes that were conjugated to CD20 antibodies (VCR-Lip-CD20). The drug release profile and the antibody-mediated targeting of the immunoliposomes were optimized to target CD20+ melanoma CIC. The immunoliposomes had desirable particle size (163 nm), drug encapsulation efficiency (91.8%), and drug release profile. We demonstrated that these immunoliposomes could successfully target more than 55% of CD20+ Chinese Hamster Ovary cells (CHO-CD20) even when the CHO-CD20 cells accounted for only 0.1% of a mixed population of CHO-CD20 and CHO cells. After treating WM266-4 melanoma mammospheres for 96 h, the ICo values of the drug delivered in VCR-Lip-CD20, VCR-Lip (VCR liposomes), and VCR were found to be 53.42, 98.99, and 99.09 µg/mL, respectively, suggesting that VCR-Lip-CD20 was 1.85 times more effective than VCR-Lip and VCR. VCR-Lip-CD20 could almost completely remove the tumorigenic ability of WM266-4 mammospheres in vivo, and showed the best therapeutic effect in WM266-4 melanoma xenograft mice. Significantly, VCR-Lip-CD20 could selectively kill CD20+ melanoma CIC in populations of WM266-4 cells both in vitro and in vivo. We demonstrated that VCR-Lip-CD20 has the potential to efficiently target and kill CD20+ melanoma CIC.

Porphine functionalized nanoparticles of star-shaped poly(ε-caprolactone)-b-D-α-tocopheryl polyethylene glycol 1000 succinate biodegradable copolymer for chemophotodynamic therapy on cervical cancer.

We developed a system of biodegradable nanoparticles (NPs) of 5,10,15,20-tetrakis(4-aminophenyl)-21H,23H-porphine (TAPP) centered, 4 arm star-shaped copolymers based on poly(ε-caprolactone) (PCL) and D-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) for combinatory chemophotodynamic therapy by using docetaxel (DTX) as a model anticancer drug and TAPP as photodynamic sensitizer. TPGS component in the copolymer plays an important role in enhancing the drug encapsulation efficiency, drug release kinetics and cellular uptake of the NPs, as well as in overcoming the multidrug resistance due to inhibition of P-glycoproteins (P-gp) of the cancer cells. We demonstrated in vitro by using the MCF7/ADR breast cancer cells of P-gp overexpression and the HeLa cervical cancer cells that the proposed chemophotodynamic therapy by the DTX-loaded TAPP-PCL-b-TPGS NPs could have much higher therapeutic effect than the original drug Taxotere®. IC50 data showed that the DTX-loaded TAPP-PCL-b-TPGS NPs chemophotodynamic therapy could be 9.36 and 56.5-fold efficient after 24 and 48h treatment, respectively in comparison with the Taxotere® chemotherapy. The in vivo investigation by employing a cervical cancer xenograft model further confirmed the advantages of the proposed chemophotodynamic therapy by the DTX-loaded TAPP-PCL-b-TPGS NPs versus the Taxotere® chemotherapy.

Nanocarriers for delivery of siRNA and co-delivery of siRNA and other therapeutic agents.

A major problem in cancer treatment is the multidrug resistance. siRNA inhibitors have great advantages to solve the problem, if the bottleneck of their delivery could be well addressed by the various nanocarriers. Moreover, co-delivery of siRNA together with the various anticancer agents in one nanocarrier may maximize their additive or synergistic effect. This review provides a comprehensive summary on the state-of-the-art of the nanocarriers, which may include prodrugs, micelles, liposomes, dendrimers, nanohydrogels, solid lipid nanoparticles, nanoparticles of biodegradable polymers and nucleic acid nanocarriers for delivery of siRNA and co-delivery of siRNA together with anticancer agents with focus on synthesis of the nanocarrier materials, design and characterization, in vitro and in vivo evaluation, and prospect and challenges of nanocarriers.

In vivo and ex vivo proofs of concept that cetuximab conjugated vitamin E TPGS micelles increases efficacy of delivered docetaxel against triple negative breast cancer.

In this study we examined the efficacy of our micellar system in xenograft models of triple negative breast cancers and explored the effect of the micelles on post-treatment tumours in order to elucidate the mechanism underlying the nanomedicine treatment in oncology. Here, we developed docetaxel-loaded vitamin E D-α-tocopheryl polyethylene glycol succinate (TPGS) micelles, of which the surface modified with cetuximab ligands for targeting epidermal growth factor receptors (EGFR) that are overexpressed in MDA-MB-231 breast cancer cells. The targeting micelles accumulated in the tumours immediately after the intravenous injection and retained for at least 24 h. The successful delivery of docetaxel into the tumours by the targeting micelles was shown by the greater degree of tumour growth inhibition than that for Taxotere(®) after the 15-day treatment. Furthermore, the explanted tumour culture study involving gene analysis and immunohistochemistry staining indicated that the in vivo micelle treatment induced cell cycle arrest and attenuated cell proliferation. In addition, the targeting and non-targeting micellar formulations brought about anti-angiogenesis and anti-migration effects. Overall, both the in vivo and ex vivo data increased the confidence that our micellar formulations effectively targeted and inhibited EGFR-overexpressing MDA-MB-231 tumours.

Co-delivery of doxorubicin and PEGylated C16-ceramide by nanoliposomes for enhanced therapy against multidrug resistance.

AIM: To develop novel nanoliposomes (Lip-ADR-Cer) codelivering doxorubicin (ADR) and PEGylated C16 ceramide (PEG-ceramide C16) to overcome multidrug resistance. MATERIALS & METHODS: The antitumor activity and mechanism of Lip-ADR-Cer were evaluated. RESULTS & CONCLUSION: The IC50 of Lip-ADR-Cer after 48-h treatment with the MCF-7/ADR and HL-60/ADR cancer cells, both being ADR resistant, was 2.2- and 1.4-fold effective respectively versus the general nanoliposomes with no PEG-ceramide C16 (Lip-ADR). The antitumor assay in mice bearing MCF-7/ADR or HL-60/ADR xenograft tumors confirmed the superior antitumor activity of Lip-ADR-Cer over Lip-ADR. We found that the improved therapeutic effect of Lip-ADR-Cer may be attributed to both of the cytotoxic effect of PEG-ceramide C16 and glucosylceramide synthase overexpression in multidrug resistance cells.

Theranostic vitamin E TPGS micelles of transferrin conjugation for targeted co-delivery of docetaxel and ultra bright gold nanoclusters.

The aim of this work was to develop an advanced theranostic micelles of D-alpha-tocopheryl polyethylene glycol 1000 succinate (TPGS), which are conjugated with transferrin for targeted co-delivery of docetaxel (DTX) as a model drug and ultra bright gold clusters (AuNC) as a model imaging agent for simultaneous cancer imaging and therapy. The theranostic micelles with and without transferrin conjugation were prepared by the solvent casting method and characterized for their particle size, polydispersity, surface chemistry, drug encapsulation efficiency, drug loading and cellular uptake efficiency. Transferrin receptors expressing MDA-MB-231-luc breast cancer cells and NIH-3T3 fibroblast cells (control cells without transferrin receptor expression) were employed as an in vitro model to access cytotoxicity of the formulations. The overexpression of transferrin receptor on the surface of MDA-MB-231-luc cells was confirmed by flow cytometry. The biodistribution study and theranostic efficacy of the micelles were investigated by using the Xenogen IVIS(®) Spectrum imaging system, which includes AuNC based fluorescence imaging and luciferase induced bioluminescence imaging on MDA-MB-231-luc tumor bearing SCID mice. The IC50 values demonstrated that the non-targeted and targeted micelles could be 15.31 and 71.73 folds more effective than Taxotere(®) after 24 h treatment with the MDA-MB-231-luc cells. Transferrin receptor targeted delivery of such micelles was imaged in xenograft model and showed their great advantages for real-time tumor imaging and inhibition of tumor growth.

Cancer nanoimmunotherapy using advanced pharmaceutical nanotechnology.

Immunotherapy is a promising option for cancer treatment that might cure cancer with fewer side effects by primarily activating the host's immune system. However, the effect of traditional immunotherapy is modest, frequently due to tumor escape and resistance of multiple mechanisms. Pharmaceutical nanotechnology, which is also called cancer nanotechnology or nanomedicine, has provided a practical solution to solve the limitations of traditional immunotherapy. This article reviews the latest developments in immunotherapy and nanomedicine, and illustrates how nanocarriers (including micelles, liposomes, polymer-drug conjugates, solid lipid nanoparticles and biodegradable nanoparticles) could be used for the cellular transfer of immune effectors for active and passive nanoimmunotherapy. The fine engineering of nanocarriers based on the unique features of the tumor microenvironment and extra-/intra-cellular conditions of tumor cells can greatly tip the triangle immunobalance among host, tumor and nanoparticulates in favor of antitumor responses, which shows a promising prospect for nanoimmunotherapy.

The chemotherapeutic potential of PEG-b-PLGA copolymer micelles that combine chloroquine as autophagy inhibitor and docetaxel as an anti-cancer drug.

Micelles may be the nanocarrier that is used most often in the area of nanomedicine due to its promising performance and technical simplicity. However, like the original drugs, micellar formulation may arouse intracellular autophagy that deteriorates their advantages for efficient drug delivery. There has been no report in the literature that involves the fate of micelles after successfully internalized into the cancer cells. In this study, we show by using docetaxel-loaded PEG-b-PLGA micelles as a micellar model that the micelles do arouse intracellular autophagy and are thus subject to degradation through the endo-lysosome pathway. Moreover, we show that co-administration of the micellar formulation with autophagy inhibitor such as chloroquine (CQ) could significantly enhance their therapeutic effects. The docetaxel-loaded PEG-b-PLGA micelles are formulated by the membrane dialysis method, which are of 7.1% drug loading and 72.8% drug encapsulation efficiency in a size range of around 40 nm with narrow size distribution. Autophagy degradation and inhibition are investigated by confocal laser scanning microscopy with various biological makers. We show that the IC50 values of the drug formulated in the PEG-b-PLGA micelles after 24 h treatment MCF-7 cancer cells with no autophagy inhibitor or in combination with CQ were 22.30 ± 1.32 and 1.75 ± 0.43 µg/mL respectively, which indicated a 12-fold more efficient treatment with CQ. The in vivo investigation further confirmed the advantages of such a strategy. The findings may provide advanced knowledge for development of nanomedicine for clinical application.

Nanotheranostics - application and further development of nanomedicine strategies for advanced theranostics.

Nanotheranostics is to apply and further develop nanomedicine strategies for advanced theranostics. This review summarizes the various nanocarriers developed so far in the literature for nanotheranostics, which include polymer conjugations, dendrimers, micelles, liposomes, metal and inorganic nanoparticles, carbon nanotubes, and nanoparticles of biodegradable polymers for sustained, controlled and targeted co-delivery of diagnostic and therapeutic agents for better theranostic effects with fewer side effects. The theranostic nanomedicine can achieve systemic circulation, evade host defenses and deliver the drug and diagnostic agents at the targeted site to diagnose and treat the disease at cellular and molecular level. The therapeutic and diagnostic agents are formulated in nanomedicine as a single theranostic platform, which can then be further conjugated to biological ligand for targeting. Nanotheranostics can also promote stimuli-responsive release, synergetic and combinatory therapy, siRNA co-delivery, multimodality therapies, oral delivery, delivery across the blood-brain barrier as well as escape from intracellular autophagy. The fruition of nanotheranostics will be able to provide personalized therapy with bright prognosis, which makes even the fatal diseases curable or at least treatable at the earliest stage.

Effects of PEG tethering chain length of vitamin E TPGS with a Herceptin-functionalized nanoparticle formulation for targeted delivery of anticancer drugs.

Drug formulation by ligand conjugated nanoparticles of biodegradable polymers has become one of the most important strategies in drug targeting. We have developed in our previous work nanoparticles of a mixture of two vitamin E TPGS based copolymers PLA-TPGS and TPGS-TOOH with the latter for Herceptin conjugation for targeted delivery of anticancer drugs such as docetaxel to the cancer cells of human epidermal growth factor receptor 2 (HER2) overexpression. In this research, we investigated the effects of the PEG chain length in TPGS, which is in fact a PEGylated vitamin E, on the cellular uptake and cytotoxicity of the drug formulated in the Herceptin-conjugated nanoparticles of PLA-TPGS/TPGS-COOH blend (NPs). Such NPs of PEG1000, PEG2000, PEG3350 and PEG5000, i.e. the PEG of molecule weight 1000, 2000, 3350 and 5000, were prepared by the nanoprecipitation method and characterized for their size and size distribution, drug loading, surface morphology, surface charge and surface chemistry as well as in vitro drug release profile, cellular uptake and cytotoxicity. We found among such nanoparticles, those of PEG1000, i.e. of the shortest PEG tethering chain length, could result in the best therapeutic effects, which are 24.1%, 37.3%, 38.1% more efficient in cellular uptake and 68.1%, 90%, 92.6% lower in IC50 (thus higher in cytotoxicity) than the Herceptin-conjugated nanoparticles of PLA-TPGS/TPGS-COOH blend of PEG2000, PEG3350 and PEG5000 respectively in treatment of SK-BR-3 cancer cells which are of high HER2 overexpression. We provided a theoretical explanation from surface mechanics and thermodynamics for endocytosis of nanoparticles.

The reduction of anti-cancer drug antagonism by the spatial protection of drugs with PLA-TPGS nanoparticles.

Docetaxel (DCL) and tamoxifen (TAM) individually are potent drugs in the fight against breast cancer. However when used in combination, they become antagonistic because of differential metabolism of both drugs. We reasoned that by spatially protecting them from metabolizing enzymes with poly (lactide)-D-α-tocopheryl polyethylene glycol succinate (PLA-TPGS) nanoparticles (NPs), we might reduce this drug antagonism. We now report that the drug antagonism between DCL and TAM in MCF7 cell line, was significantly reduced when co-delivered in PLA-TPGS NPs. In addition, this effect of NPs attenuated at high drug concentrations. To investigate the role of NPs in the reduction of drug antagonism, we quantified cellular uptake of the fluorescent model drug coumarin 6 (C6) encapsulated in a rigorous permutation of drugs-nanoparticles ratios. NPs carrying C6 exhibited enhanced cellular uptake over their free C6 counterparts at correspondingly low drug concentrations. This led us to conclude that the reduction of drug antagonism by NPs is correlated to cellular uptake and being in NPs therefore protects both drugs until they are released intracellular for therapeutic anti-cancer effect.