Research advances on antitumor mechanism of NK cells and its application in cancer targeted therapy / 药学学报

Natural killer (NK) cells, as an essential part of innate immunity, can directly identify and kill tumor cells after being activated by the synergistic action of surface inhibitory receptors and activated receptors. It can secrete cytokines to recruit dendritic cells (DCs), induce DCs maturation and enhance adaptive immune response. It can target cancer stem cells (CSCs) and circulating tumor cells (CTCs) to inhibit cancer metastasis. NK cells have a unique inflammatory tendency, which can respond to cytokines and chemokines released from tumor sites and migrate to tumor sites, making them occupy an important advantage in cancer targeted therapy. The research on cancer targeted therapy of NK cells as drug delivery carriers, NK cell membrane-coated biomimetic nanoparticles, and NK cell extracellular vesicles (NKEVs) has attracted more and more attention. The article will focus on the mechanism of NK cells inhibiting cancer, and summarize the research progress of cancer targeted therapy of NK cells.

Inhibition of chemotherapy-related breast tumor EMT by application of redox-sensitive siRNA delivery system CSO-ss-SA/siRNA along with doxorubicin treatment / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Metastasis is one of the main reasons causing death in cancer patients. It was reported that chemotherapy might induce metastasis. In order to uncover the mechanism of chemotherapy-induced metastasis and find solutions to inhibit treatment-induced metastasis, the relationship between epithelial-mesenchymal transition (EMT) and doxorubicin (DOX) treatment was investigated and a redox-sensitive small interfering RNA (siRNA) delivery system was designed. DOX-related reactive oxygen species (ROS) were found to be responsible for the invasiveness of tumor cells in vitro, causing enhanced EMT and cytoskeleton reconstruction regulated by Ras-related C3 botulinum toxin substrate 1 (RAC1). In order to decrease RAC1, a redox-sensitive glycolipid drug delivery system (chitosan-ss-stearylamine conjugate (CSO-ss-SA)) was designed to carry siRNA, forming a gene delivery system (CSO-ss-SA/siRNA) downregulating RAC1. CSO-ss-SA/siRNA exhibited an enhanced redox sensitivity compared to nonresponsive complexes in 10 mmol/L glutathione (GSH) and showed a significant safety. CSO-ss-SA/siRNA could effectively transmit siRNA into tumor cells, reducing the expression of RAC1 protein by 38.2% and decreasing the number of tumor-induced invasion cells by 42.5%. When combined with DOX, CSO-ss-SA/siRNA remarkably inhibited the chemotherapy-induced EMT in vivo and enhanced therapeutic efficiency. The present study indicates that RAC1 protein is a key regulator of chemotherapy-induced EMT and CSO-ss-SA/siRNA silencing RAC1 could efficiently decrease the tumor metastasis risk after chemotherapy.

Solid lipid nanoparticles loading adefovir dipivoxil for antiviral therapy / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Herein, solid lipid nanoparticles (SLN) were proposed as a new drug delivery system for adefovir dipivoxil (ADV). The octadecylamine-fluorescein isothiocynate (ODA-FITC) was synthesized and used as a fluorescence maker to be incorporated into SLN to investigate the time-dependent cellular uptake of SLN by HepG2.2.15. The SLN of monostearin with ODA-FITC or ADV were prepared by solvent diffusion method in an aqueous system. About 15 wt% drug entrapment efficiency (EE) and 3 wt% drug loading (DL) could be reached in SLN loading ADV. Comparing with free ADV, the inhibitory effects of ADV loaded in SLN on hepatitis B surface antigen (HBsAg), hepatitis B e antigen (HBeAg) and hepatitis B virus (HBV) DNA levels in vitro were significantly enhanced.

Preparation and quality control of low molecular weight chitosan / 中国中药杂志

<p><b>OBJECTIVE</b>To prepare the low molecular weight chitosan (LMWC) and establish the method for quality control.</p><p><b>METHOD</b>Use enzymatic degradation to prepare LMWC with chitosan, and separate by ultrafiltration; the molecular weight and purity were determined by gel permeation chromatography (GPC) and colorimetry respectively.</p><p><b>RESULT</b>LMWC was prepared by control the hours of enzymatic degradation and ultrafiltered through filter with cutoff molecular of 10K Dalton and 50 K dalton; the average molecular weight was 20 K dalton and the purity was (96.60 +/- 1.56)%.</p><p><b>CONCLUSION</b>The condition of enzymatic degradation is geniality and easy to control, LMWCs with different molecular weight can separate by ultrafiltration efficiently; the quality of LMWC can control with gel permeation chromatography (GPC) and colorimetry.</p>

Uptake of monostearin solid lipid nanoparticles by A549 cells / 药学学报

<p><b>AIM</b>To investigate the cellular uptake of monostearin solid lipid nanoparticles (MSLN) and the influence on the cellular uptake by MSLN modified with PEG2000 in human-type II cell alveolar epithelial cell line (A549) and murine macrophages cell line (J774A1).</p><p><b>METHODS</b>MSLN were prepared by a novel solvent diffusion method. The particle size distribution and zeta potential of MSLN, measured by light scattering and electrophoretic mobility, were investigated. The cytotoxicity of MSLN and MTX-loaded MSLN in A549 cells were performed by the MTT method. Rhodamine B was incorporated into solid lipid nanoparticles as fluorescent marker, after PEG2000 integrating monostearin during preparation, the cellular uptake of MSLN by A549 and J774A1 cell lines were determined spectrofluorimetrically.</p><p><b>RESULTS</b>The IC50 of MSLN and MTX-loaded MSLN on A549 cells were 227.56 microg x mL(-1) and 71.37 microg x mL(-1), respectively. The percentage of cellular uptake showed a negative correlation to the concentration of MSLN in incubation medium and the internalization behaved rapidly. Contrary to situation in J774A1 cell line, internalization of solid lipid nanoparticles was promoted with increasing the content of PEG2000 incorporated into MSLN in A549 cell line.</p><p><b>CONCLUSION</b>After modifying MSLN with PEG2000, it represents relative lower phagocytosis by J774A1 cell line and higher uptake in A549 cell line.</p>

Study of the uptake of chitosan oligosaccharide nanoparticles by A549 cells / 药学学报

<p><b>AIM</b>To study the cellular uptake of chitosan oligosaccharide nanoparticles by A549 cells and evaluate the possibility of chitosan oligosaccharide nanoparticles used as a potential drug carrier.</p><p><b>METHODS</b>Chitosan oligosaccharide (CSO) was obtained by ultrafiltration separation after regulation of the condition of chitosanase degradation. The molecular weight of CSO was determined by gel permeation chromatography (GPC). Chitosan oligosaccharide nanoparticles (CSO-NPs) were prepared by a novel solvent diffusion method in an oil system after the carrier material grafted fluorescein isothiocyanate (FITC) and the particle size distribution and zeta potential were determined by light scattering and electrophoretic mobility. The cytotoxicity and uptake of FITC-labeled CSO-NPs in A549 cells following various incubation periods were studied by the MTT method and fluorescence microscopy, flow cytometric analysis, respectively.</p><p><b>RESULTS</b>The molecular weight (MW) of CSO was 18,678 u and the particles sizes of CSO-NPs were 133.3 nm (number average) and 368.2 nm (volume average), respectively. The IC50 of CSO and CSO-NPs were 944.36 and 643.16 mg x L(-1), respectively, and the result showed low cytotoxicity. Cellular uptake of CSO and CSO-NPs were relative to the concentration and the incubation time. Internalization of CSO-NPs increased 0.49 - 13.9 times more than that of the CSO with the same incubation time.</p><p><b>CONCLUSION</b>CSO and CSO-NPs have low cytotoxicity. CSO-NPs can significantly improved the uptake of CSO-NPs by A549 cells compared to the same molecular weight of CSO.</p>

Preparation and characterization of stearic acid-grafted chitosan oligosaccharide polymeric micelles / 药学学报

<p><b>AIM</b>To prepare the micelles of stearic acid-grafted chitosan oligosaccharide and investigate the drug release from micelles.</p><p><b>METHODS</b>Mediated by a 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC), stearic acid (SA) was covalently attached to chitosan oligosaccharide (CSO), and the graft polymer (CSO-SA) was obtained. The critical aggregation concentration (CAC) of the CSO-SA was determined by measuring the fluorescence intensity of pyrene as a fluorescent probe. The effect of various pH dispersed media and concentration of tripolyphosphate sodium (TPP) on the micellar size distribution and zeta-potential measured by light scattering and electrophoretic mobility, was investigated. In buffers of different pH, the release profiles of methotrexate (MTX) from micelles were evaluated.</p><p><b>RESULTS</b>The CAC value of CSO-SA in deionized water was 0.05 g x L(-1). The mean diameter of CSO-SA micelles was 26.7 nm and the zeta potential was (55.9 +/- 0.1) mV. With the increase of TPP concentration, the size and MTX encapsulation of CSO-SA micelles increased, while the zeta-potential decreased. With the decrease of pH value of dispersed media, the size and zeta-potential of CSO-SA micelles increased, and the MTX encapsulation in CSO-SA micelles decreased. While the enhancement of drug release from the micelles was observed.</p><p><b>CONCLUSION</b>The graft polymer of CSO-SA provides polymeric micelles, which possessed a low CAC value in aqueous media. The drug release in vitro from CSO-SA micelles was affected by the pH of delivery media.</p>

Preparation of solid lipid nanoparticles by solvent diffusion method / 药学学报

<p><b>AIM</b>To establish an efficient method for preparation of solid lipid nanoparticles with high recovery.</p><p><b>METHODS</b>Monostearin solid lipid nanoparticles was prepared by solvent diffusion method in aqueous system. The recovery of the method was greatly improved by adjusting the Zeta potential.</p><p><b>RESULTS</b>The drug-loaded solid lipid nanoparticles suspension was quickly produced and easily separated with centrifugation at 4,000 r.min-1 under acidic condition. Compared with the nanoparticles made without adjusting the Zeta potential, the recovery of nanoparticles prepared in this way was significantly increased. The release behavior in vitro showed an initial burst effect in the first 3 hours followed by a slower rate stage of 4 days with nearly 6% drug released in each day.</p><p><b>CONCLUSION</b>The solvent diffusion method in aqueous system might be used as a new method to prepare solid lipid nanoparticles in the future. The loaded drug can be released in a controlled manner.</p>