Enzyme/pH dual stimuli-responsive nanoplatform co-deliver disulfiram and doxorubicin for effective treatment of breast cancer lung metastasis.

OBJECTIVES: Metastasis is still one of the main obstacles in the treatment of breast cancer. This study aimed to develop disulfiram (DSF) and doxorubicin (DOX) co-loaded nanoparticles (DSF-DOX NPs) with enzyme/pH dual stimuli-responsive characteristics to inhibit breast cancer metastasis. METHODS: DSF-DOX NPs were prepared using the amphiphilic poly(ε-caprolactone)-b-poly(L-glutamic acid)-g-methoxy poly(ethylene glycol) (PCL-b-PGlu-g-mPEG) copolymer by a classical dialysis method. In vitro release tests, in vitro cytotoxicity assay, and anti-metastasis studies were conducted to evaluate pH/enzyme sensitivity and therapeutic effect of DSF-DOX NPs. RESULTS: The specific pH and enzyme stimuli-responsiveness of DSF-DO NPs can be attributed to the transformation of secondary structure and the degradation of amide bonds in the PGlu segment, respectively. This accelerated drug release significantly increased the cytotoxicity to 4T1 cells. Compared with the control group, the DSF-DOX NPs showed a strong inhibition of in vitro metastasis with a wound healing rate of 36.50% and a migration rate of 18.39%. Impressively, in vivo anti-metastasis results indicated that the metastasis of 4T1 cells was almost completely suppressed by DSF-DOX NPs. CONCLUSION: DSF-DOX NPs with controllable tumor site delivery of DOX and DSF were a prospectively potential strategy for metastatic breast cancer treatment.

The Synergistic Mechanism of Photosynthesis and Antioxidant Metabolism between the Green and White Tissues of Ananas comosus var. bracteatus Chimeric Leaves.

Ananas comosus var. bracteatus (Ac. bracteatus) is a typical leaf-chimeric ornamental plant. The chimeric leaves are composed of central green photosynthetic tissue (GT) and marginal albino tissue (AT). The mosaic existence of GT and AT makes the chimeric leaves an ideal material for the study of the synergistic mechanism of photosynthesis and antioxidant metabolism. The daily changes in net photosynthetic rate (NPR) and stomatal conductance (SCT) of the leaves indicated the typical crassulacean acid metabolism (CAM) characteristic of Ac. bracteatus. Both the GT and AT of chimeric leaves fixed CO2 during the night and released CO2 from malic acid for photosynthesis during the daytime. The malic acid content and NADPH-ME activity of the AT during the night was significantly higher than that of GT, which suggests that the AT may work as a CO2 pool to store CO2 during the night and supply CO2 for photosynthesis in the GT during the daytime. Furthermore, the soluble sugar content (SSC) in the AT was significantly lower than that of GT, while the starch content (SC) of the AT was apparently higher than that of GT, indicating that AT was inefficient in photosynthesis but may function as a photosynthate sink to help the GT maintain high photosynthesis activity. Additionally, the AT maintained peroxide balance by enhancing the non-enzymatic antioxidant system and antioxidant enzyme system to avoid antioxidant damage. The enzyme activities of reductive ascorbic acid (AsA) and the glutathione (GSH) cycle (except DHAR) and superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) were enhanced, apparently to make the AT grow normally. This study indicates that, although the AT of the chimeric leaves was inefficient at photosynthesis because of the lack of chlorophyll, it can cooperate with the GT by working as a CO2 supplier and photosynthate store to enhance the photosynthetic ability of GT to help chimeric plants grow well. Additionally, the AT can avoid peroxide damage caused by the lack of chlorophyll by enhancing the activity of the antioxidant system. The AT plays an active role in the normal growth of the chimeric leaves.

Entrapping of Nanoparticles in Yeast Cell Wall Microparticles for Macrophage-Targeted Oral Delivery of Cabazitaxel.

In this work, a nano-in-micro carrier was constructed by loading polymer-lipid hybrid nanoparticles (NPs) into porous and hollow yeast cell wall microparticles (YPs) for macrophage-targeted oral delivery of cabazitaxel (CTX). The YPs, primarily composed of natural ß-1,3-d-glucan, can be recognized by the apical membrane receptor, dectin-1, which has a high expression on macrophages and intestinal M cells. By combining electrostatic force-driven self-deposition with solvent hydration/lyophilization methods, the positively charged NPs loaded with CTX or fluorescence probes were efficiently packaged into YPs, as verified by scanning electron microscope (SEM), atomic force mircoscope (AFM), and confocal laser scanning microscopy (CLSM) images. NP-loaded YPs (NYPs) showed a slower in vitro drug release and higher drug stability compared with NPs in a simulated gastrointestinal environment. Biodistribution experiments confirmed a widespread distribution and extended retention time of NYPs in the intestinal tract after oral administration. Importantly, a large amount of NYPs were primarily accumulated and transported in the intestinal Peyer's patches as visualized in distribution and absorption site studies, implying that NYPs were mainly absorbed through the lymphatic pathway. In vitro cell evaluation further demonstrated that NYPs were rapidly and efficiently taken up by macrophages via receptor dectin-1-mediated endocytosis using a mouse macrophage RAW 264.7 cell line. As expected, in the study of in vivo pharmacokinetics, the oral bioavailability of CTX was improved to 32.1% when loaded in NYPs, which is approximately 5.7 times higher than that of the CTX solution, indicating the NYPs are efficient for oral targeted delivery. Hence, this nano-in-micro carrier is believed to become a hopeful alternative strategy for increasing the oral absorption of small molecule drugs.

Synergistic breast tumor cell killing achieved by intracellular co-delivery of doxorubicin and disulfiram via core-shell-corona nanoparticles.

Combination therapy with different functional chemotherapeutic agents based on nano-drug delivery systems is an effective strategy for the treatment of breast cancer. However, co-delivery of drug molecules with different physicochemical properties still remains a challenge. In this study, an amphiphilic poly (ε-caprolactone)-b-poly (l-glutamic acid)-g-methoxy poly (ethylene glycol) (PCL-b-PGlu-g-mPEG) copolymer was designed and synthesized to develop a nanocarrier for the co-delivery of hydrophilic doxorubicin (DOX) and hydrophobic disulfiram (DSF). The amphiphilic copolymer self-assembled into core-shell-corona structured nanoparticles with the hydrophobic PCL core for DSF loading (hydrophobic interaction) and anionic poly (glutamic acid) shell for DOX loading (electrostatic interaction). DSF and DOX co-loaded nanoparticles (Co-NPs) resulted in high drug loading and precisely controlled DSF/DOX ratio via formulation optimization. Compared with free drug solutions, DSF and DOX delivered by the Co-NPs were found to have improved intracellular accumulation. Results of cytotoxicity assays showed that DSF/DOX delivered at the weight ratio of 0.5 and 1 could achieve a synergistic cytotoxic effect on breast cancer cell lines (MCF-7 and MDA-MB-231). In vivo imaging confirmed that the core-shell-corona nanoparticles could efficiently accumulate in tumors. In vivo anti-tumor effect results indicated that Co-NPs showed an improved drug synergistic effect on antitumor activity compared with the free drug combination. Therefore, it can be concluded that core-shell-corona nanoparticles prepared by PCL-b-PGlu-g-mPEG could be a promising co-delivery system for drug combination therapy in the treatment of breast cancer.

Enhanced oral absorption and anticancer efficacy of cabazitaxel by overcoming intestinal mucus and epithelium barriers using surface polyethylene oxide (PEO) decorated positively charged polymer-lipid hybrid nanoparticles.

Polymer-lipid hybrid nanoparticles, PMONPs, were developed to improve the oral absorption of cabazitaxel (CTX), a semi-synthetic taxane derivative, by overcoming multiple gastrointestinal barriers. The nano-carrier is comprised of a poly(ε-caprolactone) (PCL) and chain triglyceride (MCT) hybrid core for drug loading, and a positively charged surface while slightly concealed with a polyethylene oxide (PEO) shell by insertion of poloxamer 188, with the aim of improving the intestinal mucus permeation and epithelial cell uptake. The CTX-loaded PMONPs (CTX-PMONPs) were optimized with 10% MCT content in the core, and characterization showed they were on the nanoscale with a size of 170.2±5.7nm, zeta potential of +40.90±3.05mV, drug loading of 11.5%, and sustained release property. Enhanced mucus permeation of PMONPs were confirmed in a bulk permeation test, in situ SPIP and intestinal distribution study, and is likely attributed to the combined effect of positive charge and hydrophilic PEO layer on the surface. Meanwhile, promoted cellular uptake was found in mucus-secreting cells evaluation, in which potential adsorptive transcytosis, caused by positively charged surface, played a key role. Furthermore, lymphatic transport was positively demonstrated, contributing to the high oral absorption of CTX-PMONPs. The oral bioavailability of CTX was elevated from 7.7% (CTX solution (CTX-Sol)) to 56.6% after oral administration of CTX-PMONPs, approximately 7.3 times higher than that of CTX-Sol. An in vivo anticancer efficiency study showed that CTX-PMONPs orally exhibited a good tumor inhibition effect, and reduced the CTX-caused systemic toxicity compared with intravenous CTX-Sol. In conclusion, PMONPs are able to efficiently orally deliver the anticancer drug, CTX, into systemic circulation, and can achieve the desired oral anticancer effect. This surface modified polymer-lipid hybrid nanoparticle is likely to be a promising carrier for oral delivery of small molecule anticancer drugs.

Preparation and evaluation of nicotinic acid sustained-release pellets combined with immediate release simvastatin.

This study was performed to prepare high-dose nicotinic acid (NA) loaded sustained-release pellets coated with double polymer and simvastatin (SIM). The uncoated pellets were prepared by extrusion-spheronization and the double ethylcellucose (EC) films were coated in a bottom-spray fluidized bed coater. SIM was milled by wet grinding and then the milled suspension was layered on the coated pellets. Results showed that coated with 1.5% subcoating and 1% outer coating composed of EC and polyvinyl pyrrolidone K30 (PVP(K30)) in ratios of 5:1 and 2:1, NA release behavior was very similar to the reference (NER/S; SIMCOR, Abbott) in different media. And SIM was delivered more rapidly than that of the reference, while the SIM layer had no influence on NA release. During 6-month storage at 40°C/75% RH, the two drugs exhibited stable dissolution behavior. It was observed that the content uniformity of SIM was provided by the present preparation and SIM was stable if adding light magnesium oxide in the grinding procedure. Results indicated it was possible to prepare high-dose sustained-release NA pellets combined with little-dose immediate release SIM by spraying double EC polymer and SIM milled suspension on NA pellets in a bottom-spray fluidized bed coater, respectively.