Simulated Tumor Microenvironment Research Articles

Changes of Mutations and Copy-Number and Enhanced Cell Migration during Breast Tumorigenesis.

Although cancer stem cells (CSCs) play a major role in tumorigenesis and metastasis, the role of genetic alterations in invasiveness of CSCs is still unclear. Tumor microenvironment signals, such as extracellular matrix (ECM) composition, significantly influence cell behaviors. Unfortunately, these signals are often lost in in vitro cell culture. This study determines putative CSC populations, examines genetic changes during tumorigenesis of human breast epithelial stem cells, and investigates single-cell migration properties on ECM-mimetic platforms. Whole exome sequencing data indicate that tumorigenic cells have a higher somatic mutation burden than non-tumorigenic cells, and that mutations exclusive to tumorigenic cells exhibit higher predictive deleterious scores. Tumorigenic cells exhibit distinct somatic copy number variations (CNVs) including gain of duplications in chromosomes 5 and 8. ECM-mimetic topography selectively enhances migration speed of tumorigenic cells, but not of non-tumorigenic cells, and results in a wide distribution of tumorigenic single-cell migration speeds, suggesting heterogeneity in cellular sensing of contact guidance cues. This study identifies mutations and CNVs acquired during breast tumorigenesis, which can be associated with enhanced migration of breast tumorigenic cells, and demonstrates that a nanotopographically-defined platform can be applied to recapitulate an ECM structure for investigating cellular migration in the simulated tumor microenvironment.

Enzyme-responsive nano-drug delivery system for combined antitumor therapy

Efficient drug loading, tumor targeting, intratumoral penetration, and cellular uptake are the main factors affecting the effectiveness of drug delivery systems in oncotherapy. Based on the tumor microenvironment, we proposed to develop Curcumin (Cur)-loaded matrix metalloproteinase (MMP)-responsive nanoparticles (Cur-P-NPs) by static electricity, to enhance tumor targeting, cellular uptake, and drug loading efficiency. These nanoparticles combine the properties of both PEG-peptides (cleaved peptide + penetrating peptide) and star-shaped polyester (DPE-PCL) nanoparticles. Cur-P-NPs displayed good entrapment efficiency, drug loading and biocompatibility. Additionally, they showed an enhanced release rate, cellular uptake, and anti-proliferative activity by activating peptides under the simulated tumor microenvironment. Furthermore, intraperitoneal injection of losartan (LST) successfully enhanced intratumoral drug penetration by collagen I degradation. In vivo studies based on the systematic administration of the synergistic LST + Cur-P-NPs combination to mice confirmed that combined antitumor therapy with LST and Cur-P-NPs could further improve intratumor distribution, enhance anticancer efficacy, and reduce the toxicity and side effects. Therefore, LST + Cur-P-NPs represent a new and efficient system for clinical oncotherapy.

Redox-responsive self-assembled polymeric nanoprodrug for delivery of gemcitabine in B-cell lymphoma therapy

Gemcitabine, as a standard and classic strategy for B-cell lymphoma in the clinic, is limited by its poor pharmacodynamics. Although stimuli-responsive polymeric nanodelivery systems have been widely investigated in the past decade, issues such as complicated procedures, low loading capacity, and uncontrollable release kinetics still hinder their clinical translation. In view of the above considerations, we attempt to construct hyperbranched polyprodrug micelles with considerable drug loading via simple procedures and make use of the particularity of the tumor microenvironment to ensure that the micelles are “inactivated” in normal tissues and “activated” in the tumor microenvironment. Hence, in this work, a redox-responsive polymeric gemcitabine-prodrug (GEM-S-S-PEG) was one-pot synthesized via facile esterification and acylation. The self-assembled subsize (< 100 nm) GEM-S-S-PEG (GSP NPs) with considerable loading capacity (≈ 24.6%) exhibited on-demand and accurate control of gemcitabine release under a simulated tumor microenvironment and thus significantly induced the apoptosis of B-cell lymphoma in vitro. Moreover, in the A20 tumor xenograft murine model, GSP NPs efficiently decreased the expansion of tumor tissues with minimal systemic toxicity. In summary, these redox-responsive and self-assembling GSP NPs with a facile one-pot synthesis procedure may hold great potency in clinical translation for enhanced chemotherapy of B-cell lymphoma. Statement of significanceA redox-responsive polymeric gemcitabine-prodrug (GEM-S-S-PEG) was one-pot synthesized via facile esterification and acylation.The self-assembled subsize (< 100 nm) GEM-S-S-PEG (GSP NPs) exhibited significant tumor therapeutic effects in vitro and in vivo.The polyprodrug GEM-S-S-PEG prepared in this study shows the great potential of redox-responsive nanodrugs for antitumor activity, which provides a reference value for the optimization of the design of functional polyprodrugs.

Osteogenic and anti-tumor Cu and Mn-doped borosilicate nanoparticles for syncretic bone repair and chemodynamic therapy in bone tumor treatment

Critical bone defects caused by extensive excision of malignant bone tumor and the probability of tumor recurrence due to residual tumor cells make malignant bone tumor treatment a major clinical challenge. The present therapeutic strategy concentrates on implanting bone substitutes for defect filling but suffers from failures in both enhancing bone regeneration and inhibiting the growth of tumor cells. Herein, Cu and Mn-doped borosilicate nanoparticles (BSNs) were developed for syncretic bone repairing and anti-tumor treatment, which can enhance bone regeneration through the osteogenic effects of Cu2+ and Mn3+ ions and meanwhile induce tumor cells apoptosis through the hydroxyl radicals produced by the Fenton-like reactions of Cu2+ and Mn3+ ions. In vitro study showed that both osteogenic differentiation of BMSCs and angiogenesis of endothelial cells were promoted by BSNs, and consistently the critical bone defects of rats were efficiently repaired by BSNs through in vivo evaluation. Meanwhile, BSNs could generate hydroxyl radicals through Fenton-like reactions in the simulated tumor microenvironment, promote the generation of intracellular reactive oxygen species, and eventually induce tumor cell apoptosis. Besides, subcutaneous tumors of mice were effectively inhibited by BSNs without causing toxic side effects to normal tissues and organs. Altogether, Cu and Mn-doped BSNs developed in this work performed dual functions of enhancing osteogenesis and angiogenesis for bone regeneration, and inhibiting tumor growth for chemodynamic therapy, thus holding a great potential for syncretic bone repairing and anti-tumor therapy.

Study on preparation and in vitro anti-tumor activity of chitosan-modified mesoporous silica hybrids by GPTMS cross-linking agent

Using (3–glycidoxypropyl) trimethoxysilane (GPTMS) as the cross-linking agent, a novel pH-responsive nanocarrier based on chitosan/mesoporous silica hybrids (MSNs/CS) was successfully fabricated. The optimal technological conditions for the synthesis of MSNs or MSNs/CS were investigated, and the composites were characterized using field emission electron microscopy (FE-SEM), Fourier transform infrared (FT-IR) spectra, X-Ray diffraction (XRD), thermogravimetric analysis (TGA), and nitrogen adsorption/desorption isotherms, among other techniques. Haemolysis and MTT assays showed that MSNs and MSNs/CS had good biocompatibility, when the concentration of MSNs/CS was as high as 2 mg/mL, the hemolysis rate was still lower than 5%, and the cell viability of the carrier material was still greater than 80% when the concentration of MSNs/CS reached 250 μg/mL. Doxorubicin hydrochloride (DOX•HCl), as the model therapeutic agent, was released faster in simulated tumor microenvironment, and the drug loading and encapsulation efficiency of MSNs/CS were 32.47 ± 0.478% and 96.164 ± 0.0643%, respectively. Moreover, the in vitro drug release curve of MSNs/CS is highly fitted to the Higuchi equation, which indicates that the MSNs/CS-DOX•HCl system has pH response and sustained-release characteristics. Intracellular drug uptake and release experiments as well as the in-vitro anti-tumor efficacy, both demonstrated that loading DOX•HCl on the MSNs/CS improved the drug's tumor-targeted therapeutic effect. MSNs/CS synthesized by GPTMS was shown to be a novel idea for the research and development of targeted sustained and controlled-release preparations.

Fabrication of pH/Reduction Sensitive Polyethylene Glycol-Based Micelles for Enhanced Intracellular Drug Release

At present, the drug is still difficult to release completely and quickly only with single stimulation. In order to promote the rapid release of polymeric micelles at tumor site, pH/reduction sensitive polymers (PCT) containing disulfide bonds and orthoester groups were synthesized. The PCT polymers can self-assemble in water and entrap doxorubicin to form drug-loaded micelles (DOX/PCT). In an in vitro drug release experiment, the cumulative release of DOX/PCT micelles in the simulated tumor microenvironment (pH 5.0 with GSH) reached (89.7 ± 11.7)% at 72 h, while it was only (16.7 ± 6.1)% in the normal physiological environment (pH 7.4 without GSH). In addition, pH sensitive DOX loaded micellar system (DOX/PAT) was prepared as a control. Furthermore, compared with DOX/PAT micelles, DOX/PCT micelles showed the stronger cytotoxicity against tumor cells to achieve an effective antitumor effect. After being internalized by clathrin/caveolin-mediated endocytosis and macropinocytosis, DOX/PCT micelles were depolymerized in intercellular acidic and a reductive environment to release DOX rapidly to kill tumor cells. Additionally, DOX/PCT micelles had a better inhibitory effect on tumor growth than DOX/PAT micelles in in vivo antitumor activity studies. Therefore, pH/reduction dual sensitive PCT polymers have great potential to be used as repaid release nanocarriers for intercellular delivery of antitumor drugs.

Angiopep-2-Modified Carboxymethyl Chitosan-Based pH/Reduction Dual-Stimuli-Responsive Nanogels for Enhanced Targeting Glioblastoma.

Glioblastoma (GBM) is a fatal brain tumor with poor prognosis. Blood-brain barrier (BBB) prevents the effective delivery of chemotherapeutic agents to GBM. Herein, we developed a pH/reduction-sensitive carboxymethyl chitosan nanogel (CMCSN) modified by targeting peptide angiopep-2 (ANG) and loaded with doxorubicin (DOX). The multifunctional nanogel (DOX-ANG-CMCSN) exhibited good pH and reduction sensitivity, ideal stability, and biocompatibility. Its hydrodynamic diameter was 190 nm, drug loading was 12.7%, and the cumulative release rate of 24 h was 82.3% under the simulated tumor microenvironment. More importantly, the modification of ANG significantly enhanced BBB penetration and tumor targeting ability both in vivo and in vitro. DOX-ANG-CMCSN achieved 2-3-fold higher uptake and an enhanced antitumor activity compared with nontargeted DOX-CMCSN. Therefore, the targeted nanogels with the pH/reduction dual-stimuli response may provide a promising platform for GBM-targeted chemotherapy.

Harnessing Microfluidic Single Cell (MF-SC) and 3D “Organ-on-Chip” Assay Technologies for the Investigation of Immunotherapy and Study of Tumor Microenvironment (TME) in Antibody-Resistant Non-Hodgkin Lymphoma (NHL)

Introduction: Interactions between tumor and the TME occur through direct cell contacts and secreted factors such as cytokines and growth factors may influence behavior of tumor cells and response to therapy. Development of clinically applicable tumor models for screening therapeutics is desired to enhance our understanding of these mechanisms. We harnessed a novel MF-SC technology and an innovative 3D biomimetic tumor model to improve our understanding of the role of TME with immunotherapy and NHL tumor biology.Methods: Rituximab (R)- and obinutuzumab (O)-resistant (RR & OR) B-NHL cells (SUDHL4, SUDHL10 & Raji) were developed for evaluation of anti-CD20 resistance. Patient derived cell lines were obtained from newly diagnosed DLBCL patients. Functional response of anti-CD20 resistant & susceptible B-NHL cells were determined at SC levels in a customized MF droplet array platform. Single CD16+ NK cells were co-encapsulated with B-NHL cells at 1:1 effector-target (E:T) ratio in picoliter-volume droplets in presence/absence of R & O. Dynamic cellular interaction between E-T was monitored via live-cell time-lapse microscopy over 4-6 hrs to assess interaction profiles (eg, contact duration, frequency, and single vs serial interaction) and functional cytotoxicity. Target cell kill kinetics was assessed by loss of Calcein AM & ethidium homodimer uptake. Further, we used systems biology analyses (ie, Ingenuity Pathway Analysis (IPA) & Gene Set Enrichment Analysis (GSEA)) to identify associated biologic pathways. Additionally, the MF-SC platform was used to develop microscale 3D multicellular constructs to monitor effect of cancer-stroma interaction in a simulated TME. Heterogeneous tumor spheroids were generated using composite alginate hydrogels and varying combinations of NHL cells, fibroblasts & immune cells. Effect of TME (ie, cell composition and biological activity of immune cells) in the presence/absence of lenalidomide was evaluated based on extent of target cell survival/death (differentially labeled using CellTrace cell labeling & tracking dyes).Results: Development of anti-CD20 resistance in B-NHL cells resulted in decreased expression of CD20, loss of R binding, and decreased cytotoxic activity. Using IPA and GSEA systems biology analyses of RR and OR B-NHL cells, we observed conserved down-regulation of IFN-α/γ, TNF-α, inflammatory response, hypoxia and complement response pathways, and upregulation of MYC targets, which predicted overall immune suppression in all CD20 resistant cells. With MF-SC, we determined that NK cells induced variable duration of contacts with SUDHL10 cells irrespective of anti-CD20 resistance. While the single or multiple contacts made between NK & target cells occurred for an average of 45 minutes, addition of R or O resulted in significantly extended contact time (77 & 79 minutes; P <0.001 each) (Fig 1A). These contacts resulted in cell death with NK cells alone in 56% R-sensitive cells, which increased to 75% with addition of R (P <0.01). In RR cells, R increased NK cell-mediated target death from 37% (NK cells alone) to 52% in the presence of rituximab, but with perturbed cell-to-cell contact. The addition of O increased cell death (83%) in RR SUDHL10 cells (P <0.005) (Fig 1B). Primary DLBCL cells were also tested in this platform; there was NK-mediated cytotoxicity/death seen (68% in 80 minutes). We also developed a novel MF 3D lymphoma spheroid model using composite hydrogels optimized to host B-NHL cells (Fig 1C). In the presence of activated immune and stromal components, lenalidomide induced potent 2.5 fold increase in SUDHL10 cell death vs 3D cultures that lacked activated immune or stromal cells, which recapitulated the physiological mechanisms of TME-dependent lenalidomide drug activity.Conclusions: We identified that resistance to R & O occurs through biologically conserved mechanisms. Results in MF-SCs revealed that interactions between NHL tumor and immune cells is a highly dynamic process occurring through multiple cell contacts and that presence of R & O shift these kinetics; this was an important factor in determining cytotoxic immune activity. In addition, experiments based on reconstituted 3D NHL tumor spheroids validated the influence of TME mediating the activity of immunomodulatory drugs. This innovative MF-based 3D NHL spheroid model may be further leveraged for the discovery of immune-based therapeutic applications. [Display omitted] DisclosuresEvens:Celgene: Consultancy; Merck: Consultancy; • Spectrum Pharmaceuticals: Consultancy; Novartis: Consultancy; AbbVie: Consultancy; Seattle Genetics: Consultancy; Pharmacyclics: Consultancy; Kite Pharma: Consultancy; Millennium: Consultancy; Affimed: Consultancy; Amgen: Consultancy.

Artemisinin co-delivery system based on manganese oxide for precise diagnosis and treatment of breast cancer

Tumor microenvironment (TME) responsive intelligent system can realize the specific release and uniform distribution of chemotherapy drugs in tumor tissues, to achieve high-efficiency and low-toxic treatment of tumors. In this paper, drug delivery system TKD@RBCm-Mn2O3-ART with the above characteristics was constructed. We synthesized hollow mesoporous manganese trioxide (Mn2O3) nanoparticles and firstly found that they owned time-dependent size transformation feature in simulated TME. The particle size decreased from 318 nm to 50 nm and 6 nm at 1 h and 4 h in simulated TME, respectively. Then artemisinin (ART) was loaded into Mn2O3 to realize the co-delivery of Mn2+ and ART. The modification of homologous red cell membrane (RBCm) and TKD peptide was aimed at long circulation and tumor targeting in the body. In vitro results demonstrated that in the presence of GSH, the cumulative drug release percentage could achieve 97.5%. Meanwhile, Mn2O3 exhibited a good imaging capability in tumor, with the relaxation rate of 6.3113 mM−1 s−1. After entering into MCF-7 cells, TKD@RBCm-Mn2O3/ART synchronously released Mn2+ and ART to generate large amount of ROS and induce DNA damage. In vivo results proved TKD@RBCm-Mn2O3/ART could arrive the deep area of solid tumors and achieve accurate diagnosis and treatment of breast cancer.

Fluorescent traceable nanoparticles by co-self-assembly of carbon dot-drug conjugate and biodegradable hyperbranched polymer for diagnosis and therapy

Carbon dots (CDs) have attracted more interest in tumor theranostics, but they suffer from the rapid renal clearance due to small size and high hydrophilicity. To solve such problems, hydrophobic pH-triggered carbon dot-drug conjugate (CDs-Hy-DOX) with high doxorubicin (DOX) content of 48.23% were designed by covalent conjugation of DOX onto the CDs via acid-labile linkage with hydrazine (Hy) as bridge. Then the fluorescent traceable hybrid prodrug nanoparticles were fabricated via co-self-assembly with the CDs-Hy-DOX as pH-sensitive prodrug and a pH/reduction dual-triggered degradable hyperbranched polymer PEG-PO-Cy as polyethylene glycol (PEG)-based surfactant, as well as gatekeeper for pH/reduction dual-triggered DOX release. The hybrid prodrug nanoparticles with hydrodynamic diameter of 220 nm and DOX content of 22.99% were obtained with the optimized co-self-assembling condition. They could release 68.98% of DOX in the simulated tumor microenvironment within 3 days in a sustained release mode, with a premature drug leakage of 7.58%. After the acid-triggered DOX release from the CDs-Hy-DOX, which was accelerated by the pH/reduction dual-triggered degradation of the hyperbranched polymer, the strong fluorescence of CDs-Hy was recovered, demonstrating the promising potential in future tumor nanotheranostics.

Dimeric Her2-specific affibody mediated cisplatin-loaded nanoparticles for tumor enhanced chemo-radiotherapy

BackgroundSolid tumor hypoxic conditions prevent the generation of reactive oxygen species (ROS) and the formation of DNA double-strand breaks (DSBs) induced by ionizing radiation, which ultimately contributes to radiotherapy (RT) resistance. Recently, there have been significant technical advances in nanomedicine to reduce hypoxia by facilitating in situ O2 production, which in turn serves as a “radiosensitizer” to increase the sensitivity of tumor cells to ionizing radiation. However, off-target damage to the tumor-surrounding healthy tissue by high-energy radiation is often unavoidable, and tumor cells that are further away from the focal point of ionizing radiation may avoid damage. Therefore, there is an urgent need to develop an intelligent targeted nanoplatform to enable precise enhanced RT-induced DNA damage and combined therapy.ResultsHuman epidermal growth factor receptor 2 (Her2)-specific dimeric affibody (ZHer2) mediated cisplatin-loaded mesoporous polydopamine/MnO2/polydopamine nanoparticles (Pt@mPDA/MnO2/PDA-ZHer2 NPs) for MRI and enhanced chemo-radiotherapy of Her2-positive ovarian tumors is reported. These NPs are biodegradable under a simulated tumor microenvironment, resulting in accelerated cisplatin release, as well as localized production of O2. ZHer2, produced using the E. coli expression system, endowed NPs with Her2-dependent binding ability in Her2-positive SKOV-3 cells. An in vivo MRI revealed obvious T1 contrast enhancement at the tumor site. Moreover, these NPs achieved efficient tumor homing and penetration via the efficient internalization and penetrability of ZHer2. These NPs exhibited excellent inhibition of tumor growth with X-ray irradiation. An immunofluorescence assay showed that these NPs significantly reduced the expression of HIF-1α and improved ROS levels, resulting in radiosensitization.ConclusionsThe nanocarriers described in the present study integrated Her2 targeting, diagnosis and RT sensitization into a single platform, thus providing a novel approach for translational tumor theranostics.Graphic abstract

Rapid pH-responsive self-disintegrating nanoassemblies balance tumor accumulation and penetration for enhanced anti-breast cancer therapy

The dilemma of tumor accumulation and deep penetration has always been a barrier in antitumor therapy. Stimuli-responsive size changeable drug delivery systems provide possible solutions. Nevertheless, the low size-shrinkage efficiency limited the antitumor effects. In this study, an instant pH-responsive size shrinkable nanoassemblies named self-aggregated DOX@HA-CD (SA-DOX@HA-CD) was formulated using small-sized hyaluronic acid modified carbon dots (HA-CD) as monomers, which could self-aggregate into raspberry-like structure via hydrophobicity force in neutral pH and rapidly disassemble into shotgun-like DOX-loaded CD monomer in simulated tumor microenvironment (pH 6.5), owing to the transformation in electrical charge and hydrophobicity/hydrophilicity of this system. The transmission electron microscopy showed that the clustered SA-DOX@HA-CD had a diameter of ~150 nm, and thoroughly disassembled into ~30 nm nanoparticles in response to acidic environment. The disassemble efficiency was approximately 100%. Attributed to this property, SA-DOX@HA-CD led to enhanced cellular internalization and accumulation in 4T1 cells in simulated tumor microenvironment, as well as deep tumor penetration in 3D tumor spheroid model. Besides, the imine bond between DOX and HA-CD endowed DOX with pH-responsive release profile in the acidic lysosome environment. Furthermore, in the orthotopic 4T1 tumor-bearing mouse model, SA-DOX@HA-CD demonstrated higher tumor accumulation than non-aggregated DOX-HA-CD. Meanwhile, in response to the acid tumor microenvironment, the dissociated DOX-HA achieved deep tumor penetration, which consequently resulted in 2.5-fold higher antitumor efficiency. The formulation of self-aggregated SA-DOX@HA-CD provides a simple and effective alternative to prepare pH-responsive size-shrinkable nanodrug delivery systems. Statement of significanceThe heterogeneity of tumor vasculature and the high tumor interstitial pressure lead to the barriers in tumor accumulation and deep penetration, which calls for opposite properties (e.g. size) of drug delivery systems. To address this dilemma, various size changeable nanoparticles have been developed utilizing special features of tumor microenvironment, such as pH, enzyme and reactive oxygen species. Nevertheless, the current strategies face the problems of incomplete hydrolysis of chemical bonds or insufficient enzyme degradation, which result in only partial size shrinkage, hindering the tumor deep penetration effects. Here we developed a self-assembled nanocluster, which could respond to acidic pH rapidly and thoroughly disassemble into small nanodots due to the alteration of hydrophobicity/hydrophilicity/charge, leading to approximately 100% dissociation. This strategy provides a new concept for design of size changeable drug delivery systems.

Keratin-tannic acid complex nanoparticles as pH/GSH dual responsive drug carriers for doxorubicin

Drug-loaded nanoparticles have been widely used in the field of tumor treatment due to their low side effects and reduced frequency of administration. In this study, pH and glutathione (GSH) dual-responsive keratin-tannic acid (TA) complex nanoparticles were established to trigger drug release under tumor microenvironments. Reductive keratin was first extracted using a reduction method. Then, keratin-TA complex nanoparticles (KNPs) were self-assembled via non-covalent interaction and further stabilized by self-crosslinking of thiols. This method was facile and green without chemicals during the whole procedure. KNPs exhibited pH and GSH dual responsiveness as well as charge reversibility in the simulated tumor microenvironment. The anticancer drug of doxorubicin (DOX) was loaded on KNPs by hydrophobicity and hydrogen bonds. Drug-loaded KNPs accelerated drug release under mimicked tumor microenvironments, performing high toxic against A549 cells while low toxic on normal cells. Besides, drug-loaded nanoparticles could be endocytosed by tumor cells. Based on these results, KNPs may serve as drug carriers for therapeutic delivery.

Rational design of PEGylated magnetite grafted on graphene oxide with effective heating efficiency for magnetic hyperthermia application

The conceived potentials of functionalized Fe3O4 (FeNPs) make it a good candidate for magnetic hyperthermia therapy (MHT), a promising cancer therapeutic. However, decline in its performance (SAR) under alternating current magnetic field remains an intractable problem. Herein, we enhanced and optimized its SAR by rationally loading PEGylated FeNPs onto graphene oxide nanoplatform (GO) to from a superparamagnetic hybrid nanostructure (MHNS). The GO also function as an additive layer which reinforces the surfactants, improve colloidal stability, and provide surface for further derivatization thus, an avenue for multifunctionality. We delineate the effects of concentration, composition, viscosity, magnetic field strength and for the first time pH, heating media and background worming on the MHNS SAR and found that grafting PEGylated FeNPs onto GO at 4:1 loading to form MHNS improved the SAR by 1.7-fold; dispensed 2-fold heat at simulated tumor microenvironment than healthy microenvironment; timely generates high heat for prolong period; and reached 10 °C maximum temperature rise at 15 kA/m and 1.5 mg/mL. These MHNS smart-self-control attributes offer enhanced heating efficiency which is prerequisite for stable MHT performance. These findings pave the way towards developing functional MHNS for drug delivery vehicle and cancer therapy at low concentration and cellular level pH range.

Cytotoxic effect of photodynamic liposome gel combined with trastuzumab on drugresistant breast cancer cells in vitro

To evaluate the cytotoxic effect of photodynamic therapy (PDT) combined with targeted therapy using cross-linked liposomes and gels (Ce6-PC-Tmab@A-Gel) loaded with photosensitizer Chlorin (Ce6) and the tumor-targeting drug Trastuzumab (Tmab) in drug-resistant HER2+ breast cancer cells. Ce6-PC-Tmab liposomes were prepared using the thin-film hydration method. The general properties, encapsulation efficiency and near-infrared responsivity of the nanoparticles were evaluated. Ce6-PC-Tmab@A-Gel with a shear response was prepared by freeze drying and stirring crosslinking, and its microstructure was observed with scanning electron microscopy (SEM) and the shear response evaluated using a rheometer. The inhibitory effect of Ce6-PC-Tmab@A-Gel in drug-resistant HER2+ breast cancer SK-BR-3 cells was assessed with cytotoxicity assay (MTT assay) combined with near-infrared light. The particle size of Ce6-PC-Tmab was 239.7±9.7 nm and the potential was -2.03±0.09 mV. The entrapment efficiency of Tmab by Ce6-PC-Tmab liposomes was (40.22± 0.73)%. The prepared Ce6-PC-Tmab@A-Gel had a good shear response with excellent drug release characteristics under nearinfrared light, and increased intensity and duration of near-infrared light exposure enhanced Tmab release from the gel. Ce6-PC-Tmab@A-Gel was stable at room temperature and in a simulated tumor microenvironment (pH 6.25). Cytotoxicity assay (MTT) showed that Ce6-PC-Tmab@A-Gel combined with near-infrared light resulted in a survival rate of (31.37±1.73)% in SKBR-3 cells, much lower than that in the control group and other treatment groups (P < 0.01); the combined treatment also had a high efficiency of ROS production, and ROS release reached (22.36 ± 0.11)% after 2 min of near-infrared light exposure. The prepared Ce6-PC-Tmab@A-Gel has good near-infrared light response release characteristics to ensure effective targeted therapy with Tmab. The injectable gel system potentially allows long-term local drug release in the tumor to improve the treatment efficacy against drug-resistant breast cancer.

Construction, characterization, and bioavailability evaluation of honokiol-loaded porous starch by melting method without any solvent

In the present study, the porous starch (PS) was used as an efficient carrier of honokiol (HK), and the HK-loaded PS (HPS) delivery system was prepared by melting method without using organic solvents. Its physical-chemical properties, solubility and oral bioavailability were also investigated. The obtained results proved that the HK in the HPS was mostly amorphous when it was loaded into the PSs with 87.54 ± 1.52% of encapsulation efficiency (EE) and 12.51 ± 0.22% of drug loading (DL) capacity. The water-solubility of the HPS was increased to 115.27 ± 2.92 μg/mL (pH = 1.2, artificial gastric juice (AGJ)), 161.58 ± 3.42 (pH = 6.8, artificial intestinal juice (AIJ)) and 148.5 ± 1.89 μg/mL (pH = 5.5, simulated tumor microenvironment), being 6.07, 4.38 and 4.87-folds higher than free HK. In vitro dissolution tests showed the HK was significantly higher from HPS than from free HK. Furthermore, compared with free HK, the release rate and the bioavailability was also substantially improved for HK from the HPS. Meanwhile, the HPS generated a higher inhibition to HepG2 cells than free HK.

A dual-targeting Fe3O4@C/ZnO-DOX-FA nanoplatform with pH-responsive drug release and synergetic chemo-photothermal antitumor in vitro and in vivo

Designing a proper intelligent platform to target cancer cells accurately and reducing its toxic side effects on normal tissues remain a challenge in medicine application. Herein, a novel dual-targeted and tumor microenvironment-triggered Fe3O4@carbon(C)/ZnO-doxorubicin (DOX) -folic acid (FA) drug delivery system with porous structure was designed and fabricated for the first time. The co-presence of Fe3O4 core and FA molecules functioned successfully could successfully realize the magnetic targeting and cancer cell-specific targeting. In addition, pH-responsive ZnO and porous carbon both derived directly from zinc-2-methylimidazolate complex (Zn-ZIF) could play the roles of "gatekeeper" and photothermal agent, respectively. The former could efficiently block the drug within mesoporous in blood environment for decreasing the damage to the normal tissues and achieving the controlled DOX release in the simulated and real acidic tumor microenvironment. And the latter could exhibit the intrinsic photothermal conversion efficiency upon 638nm laser irradiation. Therefore, the Fe3O4@C/ZnO-DOX-FA nanoplatform integrated dual targeting, controlled chemotherapy with photothermal therapy (PTT) for cancer, displaying a significantly superior synergistic anticancer efficiency both in vitro and in vivo experiments to either monotherapy. Above results suggested the prepared nanoplatforms might be a promising candidate for effectively synergetic therapeutics to cancers.

Preparation and characterization of Keratin-PEG conjugate-based micelles as a tumor microenvironment-responsive drug delivery system

Keratin-based drug carriers have attracted great interest due to their intrinsic biocompatibility and tumor micro-environmental responsiveness. In the study, keratin was first extracted from human hair with reduction method. The reduced keratin was successively conjugated with poly(ethylene glycol) (PEG) via thiol Michael addition reaction and iodoacetic acid (IAA) via substitution reaction to impart both physical stability and acidity responsiveness. Subsequently, the conjugated keratin was fabricated into micelles and loaded with doxorubicin (DOX) by self-assembly. The micelles exhibited pH, glutathione (GSH) and enzyme (trypsin) triple-responsiveness as well as charge reversibility under the simulated tumor microenvironment. These drug-loaded micelles exhibited high toxicity against A549 cells with low side effect on normal cells. Furthermore, anticancer efficacy in vivo revealed DOX-loaded micelles presented higher therapeutic efficiency than free DOX. Moreover, these micelles were stable under physiological conditions, and could be internalized through endocytosis without hemolysis. Based on the results, the drug-loaded micelles were satisfactory candidates for drug carriers.

Amphiphilic polypeptide P23: design, synthesis, self-assembly and its encapsulation effect on doxorubicin

Polypeptides are a new type of drug carrier materials that have attracted extensive attention owing to their favorable properties like good biocompatibility and biodegradability. In this paper, we report the design and synthesis of a tumor-targeting amphiphilic polypeptide P23 (DGRKKKKAAVALLPAVLLALLAP) consisting of a hydrophilic head and hydrophobic tail containing the amino-acid sequences DGRKKKK and AAVALLPAVLLALLAP, respectively, which can self-assemble into nanospheres in an aqueous solution and encase doxorubicin (DOX). The ability for drug release and in-vitro release kinetics of the P23@DOX composite were thoroughly studied in simulated gastric juice, tumor microenvironment, and intestinal fluid models. Cytotoxicity tests demonstrated that the toxicity levels of P23 against cells were low, but P23@DOX was more cytotoxic to 4T1 tumor cells than pristine DOX, indicating that the tumor-targeting performance of P23@DOX was good and it could be used as a drug carrier in tumor-targeting drug delivery systems.

Drug‐Conjugation Induced Self‐Assembly of Feather Keratin‐Based Prodrug for Tumor Intracellular Reduction Triggered Drug Delivery

AbstractAs a kind of natural protein, keratin is widely investigated in the biomedical field. Here, for the first time, a keratin‐based prodrug (PK‐SS‐D) is designed for tumor intracellular reduction triggered drug delivery, by conjugating doxorubicin (DOX) onto poly(ethylene glycol) modified keratin (PEGylated keratin, PK) with a bioreducible disulfide linkage. The protein‐drug conjugate prodrug, with a drug content of 20%, can self‐assemble into micelles with a mean hydrodynamic diameter of 175 nm and a narrow distribution. The in vitro controlled release profiles reveal the reduction triggered thiolated DOX (DOX‐SH) release behavior of the PK‐SS‐D micelles, with a cumulative drug release up to 52% within 10 d in the simulated tumor microenvironment in a sustained releasing mode, and a low drug leakage of 17% in the simulated normal physiological medium. The enhanced tumor growth inhibition of the proposed PK‐SS‐D prodrug micelles is revealed by the methyl tetrazolium (MTT) assays, although the released DOX‐SH prodrug possesses a lower tumor growth inhibition than DOX.