A multi-stimuli responsive gold nanocage–hyaluronic platform for targeted photothermal and chemotherapy

Noninvasive and pinpointed intracellular drug release that responds to multiple stimulus is still a formidable challenge for cancer therapy. Herein, we reported a multi-stimuli responsive platform based on drug loaded gold nanocages @ hyaluronic acid (AuNCs-HA) for pinpointed intracellular drug release. These well-prepared nanohybrids could specifically recognize cancer cells via HA-CD44 interactions and be efficiently endocytosed by receptor-mediated process. Subsequently, the coated HA molecules could be degraded in lysosomes, resulting in the release of encapsulated drug. In addition, by taking advantage of the excellent photothermal properties, the AuNCs could accelerate the release of encapsulated drug and induce a higher therapeutic efficacy upon near-infrared (NIR) irradiation. In vitro results confirmed that the encapsulated drug could only be pinpointedly released in intracellular environments, which permitted high therapeutic efficacy against cancer cells and minimized the side effects. Importantly, as compared to that of the two therapies independently, a complete inhibition of tumor growth treated with the combination of chemotherapy and photothermal therapy was observed in vivo. Taken together, our present study provides new insights into developing pinpointed, multi-stimuli responsive intracellular drug release systems for synergistic cancer therapy.     

Preparation and identification of multifunctional mesoporous silica nanoparticles for in vitro and in vivo dual-mode imaging,theranostics, and targeted tracking

Mesoporous silica nanoparticles (MSNs) can provide a structural foundation for a new generation of nanocarriers with a broad range of functionalities. Multifunctional MSNs can serve as all-in-one diagnostic and therapeutic tools that can be used to simultaneously visualize and treat various diseases, such as cancer. This research study is the first time that two lanthanide-based imaging systems have been combined to incorporate controlled drug release and targeted tracing into a single MSN-based nano-platform for a novel theranostic drug delivery system. Doping lanthanide ions, i.e., europium (Eu) and gadolinium (Gd) ions, into an MSN structure (EuGd-MSNs) imparts fluorescence and magnetism to the nanostructure that can be used to develop magnetic resonance imaging (MRI) and biological fluorescence tools. Current cancer research has revealed that most human cancer cells express a large number of folate receptors on their surface. Grafting folic acid (FA) onto the EuGd-MSN surface (EuGd-FA-MSNs) imparts a targeting function to the MSN because of the specificity of the binding of FA to cell surface receptors. Furthermore, grafting anticancer drugs, such as camptothecin (CPT), onto the surface of these MSNs by forming disulfide bonds (EuGd-SS-CPT-FA-MSNs) enables intracellular controlled drug release. A high concentration of intracellular glutathione cleaves the disulfide bond to release the drug and treat the disease. The results of in vitro and in vivo studies show that the functionalized MSNs can be successfully used as a platform to integrate dual-imaging, targeting, and therapeutic treatment in multifunctional diagnosis drug delivery systems.     

Dual-function nanosystem for synergetic cancer chemo-/radiotherapy through ROS-mediated signaling pathways

Radioresistance and limitation of irradiative dosage usually lead to failure in depletion of hypoxic tumors. Herein we developed multifunctional mesoporous silica nanoparticles (MSNs) as a carrier of a novel anticancer selenoamino acid (selenocystine, SeC), to achieve synergistic chemo-/radiotherapy. This multifunctional nanosystem effectively sensitizes cancer cells to X-ray radiotherapy. Conjugation of TAT cell penetrating peptide and transferrin to the surface of MSNs significantly enhances its internalization in cancer cells through receptor-mediated endocytosis. SeC@MSNs-Tf/TAT significantly enhanced X-ray-induced growth inhibition in cervical cancer cells by induction of apoptosis, mainly through death receptor-mediated extrinsic apoptotic pathway. Upon radiation, SeC@MSNs-Tf/TAT promoted intracellular ROS overproduction, which induced apoptotic cell death by affecting p53, AKT and MAPKs pathways. Furthermore, SeC@MSNs-Tf/TAT also significantly inhibited HeLa tumor growth in nude mice model through suppression of cell proliferation and induction of apoptosis. In vivo toxicity of the SeC@MSNs-Tf/TAT nanoparticles was investigated using the mouse model. The results of histological analysis revealed that, the nanoparticles did not show any obvious damage to these major organs under the experimental conditions, including heart, liver, spleen, lung and kidney. Taken together, this study demonstrates an effective and safe strategy for cancer-targeted chemo-/radiotherapy of human cancers.     

Hyaluronic acid-chitosan nanoparticles for co-delivery of MiR-34a and doxorubicin in therapy against triple negative breast cancer

Metastatic relapse, development of drug resistance in cancer cells and adverse side effects of chemotherapeutic agents are the major obstacles for effective chemotherapy against triple-negative breast cancer. To address these problems, miR-34a, a potent endogenous tumor suppressive molecule in breast cancer, was co-encapsulated with doxorubicin (DOX) into hyaluronic acid (HA)-chitosan (CS) nanoparticles (NPs) and simultaneously delivered into breast cancer cells for improved therapeutic effects of drug. DOX-miR-34a co-loaded HA-CS NPs were successfully prepared through ionotropic gelation method in water. In vitro and in vivo experiments showed that miR-34a and DOX can be efficiently encapsulated into HA-CS NPs and delivered into tumor cells or tumor tissues and enhance anti-tumor effects of DOX by suppressing the expression of non-pump resistance and anti-apoptosis proto-oncogene Bcl-2. In addition, intracellular restoration of miR-34a inhibited breast cancer cell migration via targeting Notch-1 signaling. The obtained data suggest that co-delivery of DOX and miR-34a could achieve synergistic effects on tumor suppression and nanosystem-based co-delivery of tumor suppressive miRNAs and chemotherapeutic agents may be a promising combined therapeutic strategy for enhanced anti-tumor therapy.     

Surfactant-assisted controlled release of hydrophobic drugs using anionic surfactant templated mesoporous silica nanoparticles

A series of mesoporous silica nanoparticles (MSNs) were synthesized using the co-structure directing method. A non-cytotoxic anionic surfactant, undec-1-en-11-yltetra(ethylene glycol) phosphate monoester surfactant (PMES), was used as a structure directing agent (SDA) together with aminopropyltrimethoxysilane that functioned as a co-structure directing agent (CSDA). The morphology and mesoporous structure of these materials were tuned by changing the molar ratio of CSDA and SDA. These mesoporous nanomaterials containing PMES inside the pores showed excellent biocompatibility in vitro. The cellular internalization and endosome escape of PMES-MSNs in cervical cancer cells (HeLa) was demonstrated by flow cytometry and confocal microscopy, respectively. The PMES-MSNs were used as drug delivery carriers for resveratrol, a low water solubility drug, by taking advantage of the hydrophobic environment created by the PMES micelle inside the pores. This surfactant-assisted delivery strategy was tested under physiological conditions showing an increase of the drug loading compared to the material without surfactant and steady release of resveratrol. Finally, the therapeutic properties of resveratrol-loaded PMES-MSNs were evaluated in vitro using HeLa and Chinese hamster ovarian cells. We envision that this surfactant-assisted drug delivery method using MSNs as nanovehicles would lead to a new generation of carrier materials for intracellular delivery of a variety of hydrophobic therapeutic agents.     

Increasing the cytotoxicity of doxorubicin in breast cancer MCF-7 cells with multidrug resistance using a mesoporous silica nanoparticle drug delivery system

Resistance to cytotoxic chemotherapy is the main cause of therapeutic failure and death in women with breast cancer. Overexpression of various members of the superfamily of adenosine triphosphate binding cassette (ABC)-transporters has been shown to be associated with multidrug resistance (MDR) phenotype in breast cancer cells. MDR1 protein promotes the intracellular efflux of drugs. A novel approach to address cancer drug resistance is to take advantage of the ability of nanocarriers to sidestep drug resistance mechanisms by endosomal delivery of chemotherapeutic agents. Doxorubicin (DOX) is an anthracycline antibiotic commonly used in breast cancer chemotherapy and a substrate for ABC-mediated drug efflux. In the present study, we developed breast cancer MCF-7 cells with overexpression of MDR1 and designed mesoporous silica nanoparticles (MSNs) which were used as a drug delivery system. We tested the efficacy of DOX in the breast cancer cell line MCF-7/MDR1 and in a MCF-7/MDR1 xenograft nude mouse model using the MSNs drug delivery system. Our data show that drug resistance in the human breast cancer cell line MCF-7/MDR1 can be overcome by treatment with DOX encapsulated within mesoporous silica nanoparticles.     

Biofunctionalized polymer-lipid supported mesoporous silica nanoparticles for release of chemotherapeutics in multidrug resistant cancer cells

Multidrug resistance (MDR) is a major impediment to the success of cancer chemotherapy. A polymer-lipid supported mesoporous silica nanoparticle (PLS-MSNs) is described here to facilitate intracellular delivery of anticancer drug and enhance the antitumor efficacy against MDR breast cancer cells. By coating MSNs with a synthetic dual-functional polymer-lipid material P123-DOPE, the supported membrane acted as an intact barrier against the escape of encapsulated drugs before reaching the target cells, leading to depolymerization and triggered storm release of loaded irinotecan (CPT-11) in acidic endosomal pH of tumor cells. In addition, P123-DOPE can inhibit breast cancer resistance protein (BCPR) mediated CPT-11 efflux in drug resistant MCF-7/BCRP breast cancer cells, thus acting as a “door blocker”. Compared to free CPT-11, PLS-MSNs resulted in a maximum increase in the intracellular CPT-11 concentration (12.9-fold), had 7.1-fold higher cytotoxicity and processed a stronger cell cycle arrest in MCF-7/BCRP cells. Moreover, CPT-11 loaded PLS-MSNs showed high therapeutic performance and low toxicity in BALB/c nude mice bearing drug resistant breast tumors, with an inhibition rate of 81.2% compared to free CPT-11 treatment group. The reported PLS-MSNs provide promising applicability in future preclinical and clinical MDR cancer treatment.     

Effect of size on the cellular endocytosis and controlled release of mesoporous silica nanoparticles for intracellular delivery

Due to the unique physicochemical properties and membrane-permeable capacity, mesoporous silica nanoparticles (MSNs) are considered as an ideal carrier for intracellular delivery. Herein, we endeavored to address the size effect of MSNs on the cellular uptake, endosomal escape and controlled release, the key steps for the intracellular delivery. The well-ordered MSNs in the range from 55-nm to 440-nm with similar pore texture were prepared by modified base-catalyzed sol–gel method. With MC3T3-E1 model cell line, the in vitro results indicated that after 12 h cultivation, MSNs within 55 ~ 440 nm could all be internalized into the cells, and further escaped out of the endosomal compartment. The efficiency of the cellular uptake and endosomal escape strongly depended on the particle size, with the best efficiencies from 100-nm MSNs. Furthermore, the MTT results indicated that these MSNs materials were all biocompatible. The controlled release experiments with hydrophobic dexamethasone and hydrophilic vitamin C as models showed that for these small-molecular drugs, the loading amount all mainly determined by the surface area of the MSNs, and the subsequent release of the drug dramatically decreased with the increasing of the particle size. By contrast, the release rate of vitamin C was much quicker than that of the dexamethasone. These findings presented here could provide new means to tailor the size of MSNs and thus to guide the design of MSNs-based intracellular delivery system. Due to the good cell biocompatibility, high cellular uptake and endosomal escape, we conjectured that the 100-nm MSNs are more favorable for the intracellular delivery of drugs in live cells.     

Enhanced intracellular translocation and biodistribution of gold nanoparticles functionalized with a cell-penetrating peptide (VG-21) from vesicular stomatitis virus

Reduced toxicity and ease of modification make gold nanoparticles (GNPs) suitable for targeted delivery, bioimaging and theranostics by conjugating cell-penetrating peptides (CPPs). This study presents the biodistribution and enhanced intracellular uptake of GNPs functionalized with VG-21, a CPP derived from vesicular stomatitis virus glycoprotein (G). Cell penetrating efficiency of VG-21 was demonstrated using CellPPD web server, conjugated to GNPs and were characterized using, UV-visible and FTIR spectroscopy, transmission electron microscopy, dynamic light scattering and zeta potential. Uptake of VG-21 functionalized GNPs (fGNPs) was tested in eukaryotic cell lines, HEp-2, HeLa, Vero and Cos-7, using flow cytometry, fluorescence and transmission electron microscopy (TEM), and inductively coupled plasmon optical emission spectroscopy (ICP-OES). The effects of nanoparticles on stress and toxicity related genes were studied in HEp-2 cells. Cytokine response to fGNPs was studied in vitro and in vivo. Biodistribution of nanoparticles was studied in BALB/c mice using TEM and ICP-OES. VG-21, GNPs and fGNPs had little to no effect on cell viability. Upon exposure to fGNPs, HEp-2 cells revealed minimal down regulation of stress response genes. fGNPs displayed higher uptake than GNPs in all cell lines with highest internalization by HEp-2, HeLa and Cos-7 cells, in endocytotic vesicles and nuclei. Cytokine ELISA showed that mouse J774 cells exposed to fGNPs produced less IL-6 than did GNP-treated macrophage cells, whereas TNF-α levels were low in both treatment groups. Biodistribution studies in BALB/c mice revealed higher accumulation of fGNPs than GNPs in the liver and spleen. Histopathological analyses showed that fGNP-treated mice accumulated 35 ng/mg tissue and 20 ng/mg tissue gold in spleen and liver respectively, without any adverse effects. Likewise, serum cytokines were low in both GNP- and fGNP-treated mice. Thus, VG-21-conjugated GNPs have enhanced cellular internalization and are suitable for various biomedical applications as nano-conjugates.     

A chitosan-graft-PEI-candesartan conjugate for targeted co-delivery of drug and gene in anti-angiogenesis cancer therapy

A multifunctional copolymer–anticancer conjugate chitosan-graft-polyethyleneimine-candesartan (CPC) containing low molecular weight chitosan (CS) backbone and polyethyleneimine (PEI) arms with candesartan (CD) conjugated via an amide bond was fabricated as a targeted co-delivery nanovector of drug and gene for potential cancer therapy. Here, CD was utilized to specifically bind to overexpressed angiotensin II type 1 receptor (AT₁R) of tumor cells, strengthen endosomal buffering capacity of CPC and suppress tumor angiogenesis. The self-assembled CPC/pDNA complexes exhibited desirable and homogenous particle size, moderate positive charges, superior stability, and efficient release of drug and gene in vitro. Flow cytometry and confocal laser scanning microscopy analyses confirmed that CD-targeted function and CD-enhanced buffering capacity induced high transfection, specific cellular uptake and efficient intracellular delivery of CPC/pDNA complexes in AT₁R-overexpressed PANC-1 cells. In addition, CPC/wt-p53 complexes co-delivering CD and wild type p53 (wt-p53) gene achieved synergistic angiogenesis suppression by more effectively downregulating the expression of vascular endothelial growth factor (VEGF) mRNA and protein via different pathways in vitro, as compared to mono-delivery and mixed-delivery systems. In vivo investigation on nude mice bearing PANC-1 tumor xenografts revealed that CPC/wt-p53 complexes possessed high tumor-targeting capacity and strong anti-tumor activity. Additional analysis of microvessel density (MVD) demonstrated that CPC/wt-p53 complexes significantly inhibited tumor-associated angiogenesis. These findings suggested that CPC could be an ideal tumor-targeting nanovector for simultaneous transfer of drug and gene, and a multifunctional CPC/wt-p53 co-delivery system with tumor-specific targetability, enhanced endosomal buffering capacity and synergistic anti-angiogenesis efficacy might be a new promising strategy for effective tumor therapy.     

Carrier-free functionalized multidrug nanorods for synergistic cancer therapy

We developed carrier-free multidrug nanocrystals (MDNCs) for the combination chemotherapy with synergistic effect, improved tolerance and imaging capability for cancer treatment. Three widely used hydrophobic drugs, methotrexate (MTX), 10-hydroxycamptothecin (HCPT) and paclitaxel (PTX), were prepared into one nanorod, and then conjugated with poly(ethylene glycol) (PEG) to improve their water dispersity and bio-environmental stability. It should be noted that only trace amount of PEG was used for surface modification, which ensures a high drug loading capacity of the resulting PEGylated MDNCs. In vitro studies showed that the MDNCs revealed an obviously higher cytotoxicity than individual drugs in the same dose and suppressed drug resistance against PTX resistant MCF-7/ADR cancer cells, indicating its synergistic effect and improved tolerance. After in vivo intravenous injection, the MDNCs exhibits a synergetic in vivo therapeutic effect and possesses obviously superior antitumor effect compared to free multidrugs treatment group and individual drug treatment groups, and no statistically significant weight loss was observed. The MDNCs can also gain imaging capabilities by encapsulated with an organic dye, which render the multidrug nanorod an all-in-one processing system for cancer diagnosis and treatment.     

Synthesis of nanocarriers with remote magnetic drug release control and enhanced drug delivery for intracellular targeting of cancer cells

Nanotherapeutic strategy is well recognized as the therapeutic approach of the future. Numerous reports have demonstrated the use of nanoparticulate drug carriers for the development of targeted nanotherapeutics by, for instance, incorporation of a moiety that specifically targets certain diseased cells. However, systematic investigation of this aspect has been inadequate, especially with regard to nanosystems with remotely controlled drug delivery. The authors previously designed a magnetic-responsive core-shell drug delivery nanosystem which proved to be technically feasible in vitro. In the present study, this nanosystem is modified for targeted delivery of an anticancer agent (encapsulated camptothecin (CPT)) to cancer cells overexpressing epithelial growth factor receptor (EGFR) with accurate intracellular drug release. The endocytosis of the nanocarriers by cancer cells, the pathway of cellular uptake and the subsequent intracellular controlled drug delivery were systematically investigated. It was found that the modified nanocarriers showed reasonably high drug load efficiency for CPT and a high uptake rate by cancer cells overexpressing EGFR through clathrin-mediated endocytosis. The intracellular release of the CPT molecules via an external magnetic stimulus proved to be technically successful and ensured much higher therapeutic efficacy than that obtained with the free drug. This study employs multiple functions for nanotherapeutic treatment of specific target cells, i.e. cell-specific targeting, controlled cellular endocytosis and magnetic-responsive intracellular drug release.     

pH-sensitive Laponite®/doxorubicin/alginate nanohybrids with improved anticancer efficacy

The efficacy of the anticancer drug doxorubicin (Dox) is limited by an insufficient cellular uptake and drug resistance, which is partially due to ion trapping in acidic environments such as the extracellular environment of solid tumors and the interior of endolysosome vesicles. Herein, we describe the preparation and in vitro evaluation of a new type of nanohybrid for anticancer drug delivery which is capable of carrying a high load of the cationic Dox through the cell membrane. In addition, the nanohybrids use the acidic environment of the endolysosomes to release the drug, simultaneously helping to disrupt the endolysosomes and diminishing endolysosome Dox trapping. Furthermore, as the nanohybrid carriers are capable of sustained drug delivery, those that remain in the cytoplasm and still contain Dox are expected to exert a prolonged anticancer activity. Briefly, Dox is loaded onto biocompatible anionic Laponite® (LP) nanodisks with a high aspect ratio (25 nm in diameter and 0.92 nm in thickness) through strong electrostatic interactions to get Dox-loaded LP disks. Alginate (AG), a biocompatible natural polymer, is then coated onto the Dox-loaded LP disks (LP/Dox/AG nanohybrids) to prevent the burst release of the drug. The results demonstrate that the nanohybrids have a high encapsulation efficiency (80.8 ± 10.6%), are sensitive to pH and display a sustained drug release behavior. Cell culture experiments indicate that the LP/Dox/AG nanohybrids can be effectively internalized by CAL-72 cells (an osteosarcoma cell line), and exhibit a remarkable higher cytotoxicity to cancer cells than the free Dox. The merits of Laponite®/alginate nanohybrids, such as biocompatibility, high loading capacity and stimulus responsive release of cationic chemotherapeutic drugs, render them as excellent platforms for drug delivery.     

Deoxycholate bile acid directed synthesis of branched Au nanostructures for near infrared photothermal ablation

We report an approach for simple, reproducible and high-yield synthesis of branched GNPs directed by deoxycholate bile acid supramolecular aggregates in Au solution. A growth process involving stepwise trapping of the GNP seeds and Au ions in the deoxycholate bile acid solution yields multiple-branched GNPs. Upon NIR laser irradiation strong NIR absorption for branched GNPs induced photothermal-heating to destroy tumor cells. Subsequently, these branched GNPs were biofunctionalized with cRGD cell penetrating-targeting peptides for photothermal cancer treatment applications. Branched GNPs conjugated with cRGD peptides enhanced internalization of the branched GNPs in BxPC3 human pancreatic adenocarcinoma cells and effectively ablated BxPC3 cells when irradiated with a NIR laser (808 nm). Their potential use as photothermal transducing agents was demonstrated in in vivo settings using a pancreatic cancer xenograft model. The tumors were effectively ablated with cRGD-branched GNPs injection and laser exposure without any observation of tumor recurrence. This firstly reported method for deoxycholate bile acid directed synthesis of branched GNPs opens new possibilities for the production of strong NIR absorbing nanostructures for selective nano-photothermolysis of cancer cells and the further design of novel materials with customized spectral and structural properties for broader applications.     

Nano-assemblies of J-aggregates based on a NIR dye as a multifunctional drug carrier for combination cancer therapy

The combination of chemotherapy with photothermal therapy, which may lead to improved therapeutic efficacies and reduced side effects of conventional chemotherapy, would require safe drug delivery systems (DDSs) with strong near-infrared (NIR) absorbance, efficient drug loading, and effective tumor homing ability. Herein, we fabricate nano-assemblies containing J-aggregates of a NIR dye, IR825, for drug delivery and combined photothermal & chemotherapy of cancer. It is found that IR825 could be complexed with a low-molecular-weight cationic polymer polyethylenimine (PEI), forming IR825@PEI J-aggregates with greatly enhanced NIR absorbance red-shifted to 915 nm. Those nano-assemblies of J-aggregates are further modified with polyethylene glycol (PEG), obtaining IR825@PEI-PEG nano-complex which exhibits great dispersity in physiological solutions, excellent photostability, and is able to efficiently load chemotherapeutic drug doxorubicin (DOX) via a unique strategy different from drug loading in conventional amphiphilic polymer-based DDSs. In vivo animal experiments uncover that IR825@PEI-PEG/DOX upon intravenous injection into tumor-bearing mice shows rather high tumor uptake as illustrated by photoacoustic imaging. In vivo combined photothermal & chemotherapy is then carried out, demonstrating great synergistic anti-tumor therapeutic effect remarkably superior to those achieved by the respective mono-therapies. Hence, we present a novel type of nanoscale DDSs based on nano-assemblies of small molecules without involving amphiphilic polymers, promising for imaging-guided combination cancer therapy.     

介孔二氧化硅纳米颗粒经氧化应激所致肾细胞毒性及GSK-3β在其中的作用

研究氧化应激及GSK-3β在介孔二氧化硅纳米颗粒(MSNs)诱导肾细胞毒性中的作用及机制,以及抗氧化剂N-乙酰半胱氨酸(NAC)在此毒性中的保护作用。选用NRK-52E大鼠的肾小管上皮细胞,将其直接或用1 μmol/L NAC预处理,然后暴露于400 μg/mL MSNs中。采用MTT法测定细胞活力,采用JC-1荧光染色法检测线粒体膜电势,采用western blot 法检测GSK-3β等蛋白水平,并测定抗氧化物SOD、GSH和CAT活性。NRK-52E细胞暴露于MSNs内24 h即出现严重的细胞毒性,其IC₅₀为(438.6±7.1) μg/mL。400 μg/mL MSNs作用24 h后,细胞的存活率下降到47.57%±2.03%,胞内SOD、GSH、CAT活性水平分别下降到39.74%±2.23%、51.42%±3.08%、46.05%±3.71%(P<0.001)。400 μg/mL MSNs还可显著活化GSK-3β,崩解线粒体ΔΨ_m,促进线粒体Cyt C漏出,并剪切激活Caspase-3,引起细胞死亡(P<0.001);1 μmol/L NAC干预后可显著缓解400 μg/mL MSNs引起的这些变化(P<0.01)。MSNs通过激活GSK-3β信号通路来诱导肾细胞氧化应激损伤,NAC可以改善线粒体功能,提高细胞抗氧化能力,减轻此损伤。     

The performance of thiol-terminated PEG-paclitaxel-conjugated gold nanoparticles

A series of thiol-terminated polyethylene glycol (PEG)-paclitaxel (PTX) derivatives are designed and synthesized to fabricate PTX-conjugated gold nanoparticles (PTX@GNPs) and improve their overall performance. By extending the molecular weight of PEG from 400 to 1000 Da, the optimized water solubility of the conjugate reaches 184 mg/mL, equal to 4.6 × 10⁵ times that of PTX alone (0.4 μg/mL). High drug loading is obtained by eliminating the steric hindrance between PTX molecules on the surface of GNPs. The gold conjugate shows double simultaneous stimulation-induced drug release behavior in the presence of both esterase and high concentrations of glutathione. The synergic release characteristics of this conjugate results in significant performance improvements, including prolonged circulation due to high stability in vivo, targeted release of PTX inside tumor cells, and increased tumor cell killing efficiency. Improving the in vitro properties of the conjugate not only significantly enhances its therapeutic efficacy in a murine liver cancer model, but also allows drug-conjugated gold nanoparticles to be used as a promising nanoprodrug system in the cancer therapeutics.     

赫赛汀对吉非替尼诱导肺癌A549细胞凋亡的影响

目的： 研究吉非替尼与赫赛汀联合应用对人肺腺癌A549 细胞凋亡的影响。方法: 应用MTT法,流式细胞仪Annexin V－PI 双标法、DAPI荧光染色等多项方法,体外研究吉非替尼与赫赛汀联合对A549 细胞的促凋亡作用。结果: 吉非替尼与赫赛汀单独应用及联合应用均可以明显抑制人肺腺癌A549细胞的生长，促进细胞凋亡,并呈浓度及时间依赖性,2者联合作用人肺腺癌A549 细胞24 h、48 h、72 h 的凋亡率显著高于单用吉非替尼或赫赛汀组(P<0.05),2者呈现出相加的抗瘤效果。结论: 吉非替尼与赫赛汀联合应用在体外对人肺腺癌A549 细胞有明显的促凋亡作用。     

Enhancement of cell recognition in vitro by dual-ligand cancer targeting gold nanoparticles

A dual-ligand gold nanoparticle (DLGNP) was designed and synthesized to explore the therapeutic benefits of multivalent interactions between gold nanoparticles (GNPs) and cancer cells. DLGNP was tested on human epidermal cancer cells (KB), which had high expression of folate receptor. The cellular uptake of DLGNP was increased by 3.9 and 12.7 folds compared with GNP-folate or GNP-glucose. The enhanced cell recognition was due to multivalent interactions between both ligands on GNPs and cancer cells as shown by the ligand competition experiments. Furthermore, the multivalent interactions increased contrast between cells with high and low expression of folate receptors. The enhanced cell recognition enabled DLGNP to kill KB cells under X-ray irradiation at a dose that was safe to folate receptor low-expression (such as normal) cells. Thus DLGNP has the potential to be a cancer-specific nano-theranostic agent.     

A nanogel of on-site tunable pH-response for efficient anticancer drug delivery

A smart, soft and small nanoparticulate drug carrier that can efficiently transport therapeutics into tumor cells to control the intracellular drug concentration will enable major advancements in cancer therapy. To facilitate a remote modulation of the intracellular pH-regulated drug release, we have designed a new class of pH-responsive chitosan-based nanogels (<200 nm) by the physical interpenetration of chitosan chains into a nonlinear poly(ethylene glycol) (nonlinear PEG) chain network. The resultant PEG-chitosan nanogels not only respond to the changes in environmental pH over the physiologically important range of 5.0–7.4, but – more importantly – also enable us to remotely modulate the pH response by external cooling/heating. The nanogel, as well as the nanogel loaded with a model anticancer drug 5-fluorouracil (5-FU), is capable of varying its surface charge from nearly neutral to positive around tumor extracellular pH (～6.0–6.2) to facilitate cell internalization. Subsequently, the significantly increased acidity in subcellular compartments (～5.0) can trigger 5-FU release from the endocytosed drug carriers. While this nanogel serving as a drug carrier exhibits a reduced toxicity in combined chemo-thermo treatments, it has shown significantly enhanced therapeutic efficacy in combined chemo-cryo treatments of the model B16F10 melanoma cells, indicating its great potential for cancer therapy.