Remdesivir alleviates skin fibrosis by suppressing TGF-ß1 signaling pathway.

Fibrotic skin diseases, such as keloids, are pathological results of aberrant tissue healing and are characterized by overgrowth of dermal fibroblasts. Remdesivir (RD), an antiviral drug, has been reported to have pharmacological activities in a wide range of fibrotic diseases. However, whether RD function on skin fibrosis remains unclear. Therefore, in our study, we explored the potential effect and mechanisms of RD on skin fibrosis both in vivo and in vitro. As expected, the results demonstrated that RD alleviated BLM-induced skin fibrosis and attenuates the gross weight of keloid tissues in vivo. Further studies suggested that RD suppressed fibroblast activation and autophagy both in vivo and in vitro. In addition, mechanistic research showed that RD attenuated fibroblasts activation by the TGF-ß1/Smad signaling pathway and inhibited fibroblasts autophagy by the PI3K/Akt/mTOR signaling pathway. In summary, our results demonstrate therapeutic potential of RD for skin fibrosis in the future.

Inhalation Lenalidomide-Loaded Liposome for Bleomycin-Induced Pulmonary Fibrosis Improvement.

Idiopathic pulmonary fibrosis (IPF) is a progressive, fibrotic interstitial lung disease with unclear etiology and increasing prevalence. Pulmonary administration can make the drug directly reach the lung lesion location and reduce systemic toxic and side effects. The effectiveness of lenalidomide (Len) liposomal lung delivery in idiopathic pulmonary fibrosis was investigated. Len liposomes (Len-Lip) were prepared from soybean lecithin, cholesterol (Chol), and medicine in different weight ratios by thin film hydration method. The Len-Lip were spherical in shape with an average size of 226.7 ± 1.389 nm. The liposomes with a higher negative zeta potential of around - 34 mV, which was conducive to improving stability by repelling each other. The drug loading and encapsulation rate were 2.42 ± 0.07% and 85.47 ± 2.42%. Len-Lip had little toxicity at the cellular level and were well taken up by cells. At bleomycin-induced pulmonary fibrosis model mice, inhalation Len-Lip could improve lung function and decrease lung hydroxyproline contents, and alleviate pulmonary fibrosis state. Inhalation Len-Lip provided a reference for the treatment of idiopathic pulmonary fibrosis.

Integrated room temperature single-photon source for quantum key distribution.

High-purity single-photon sources (SPS) that can operate at room temperature are highly desirable for a myriad of applications, including quantum photonics and quantum key distribution. In this work, we realize an ultra-bright solid-state SPS based on an atomic defect in hexagonal boron nitride (hBN) integrated with a solid immersion lens (SIL). The SIL increases the source efficiency by a factor of six, and the integrated system is capable of producing over ten million single photons per second at room temperature. Our results are promising for practical applications of SPS in quantum communication protocols.

Integrated room temperature single-photon source for quantum key distribution: publisher's note.

This publisher's note contains a correction to Opt. Lett.47, 1673 (2022)10.1364/OL.454450.

Preparation and Anti-tumor Study of Dextran 70,000-Selenium Nanoparticles and Poloxamer 188-Selenium Nanoparticles.

The anti-tumor effect of selenium nanoparticles (SeNPs) has received more and more attention. However, the clinical application of SeNPs is not optimistic due to the poor stability. To improve the stability of SeNPs, many polymers are used to modify the SeNPs. However, most of the polymers are not approved by FDA. It is significant to develop a SeNPs product with good stability for clinic application. Dextran 70,000 (T70) and poloxamer 188 (P188) are FDA-approved pharmaceutical injection excipients. In this study, we decorate SeNPs with T70 and P188 and assess the physicochemical characterization, storage stability, and anti-tumor activities of T70-SeNPs and P188-SeNPs. Transmission electron microscopy (TEM) shows that T70-SeNPs and P188-SeNPs are spherical particles with particle sizes of 110 nm and 60 nm respectively. Fourier-Transform Infrared Spectra (FT-IR) show that T70 or P188 can interact with SeNPs through hydrogen bonding. Stability study shows that P188-SeNPs freeze-dried powder and T70-SeNPs freeze-dried powder remain stable at 4℃ for 6 months. T70-SeNPs and P188-SeNPs can aggregate in cell matrix and play an anti-tumor role to HepG2 by promoting apoptosis, increasing reactive oxygen species (ROS) content and reducing mitochondrial membrane potential (MMP). This study can provide reference for industrial production of SeNPs products.

Extracellular vesicles from hypoxia-preconditioned microglia promote angiogenesis and repress apoptosis in stroke mice via the TGF-ß/Smad2/3 pathway.

Systemic transplantation of oxygen-glucose deprivation (OGD)-preconditioned primary microglia enhances neurological recovery in rodent stroke models, albeit the underlying mechanisms have not been sufficiently addressed. Herein, we analyzed whether or not extracellular vesicles (EVs) derived from such microglia are the biological mediators of these observations and which signaling pathways are involved in the process. Exposing bEnd.3 endothelial cells (ECs) and primary cortical neurons to OGD, the impact of EVs from OGD-preconditioned microglia on angiogenesis and neuronal apoptosis by the tube formation assay and TUNEL staining was assessed. Under these conditions, EV treatment stimulated both angiogenesis and tube formation in ECs and repressed neuronal cell injury. Characterizing microglia EVs by means of Western blot analysis and other techniques revealed these EVs to be rich in TGF-ß1. The latter turned out to be a key compound for the therapeutic potential of microglia EVs, affecting the Smad2/3 pathway in both ECs and neurons. EV infusion in stroke mice confirmed the aforementioned in vitro results, demonstrating an activation of the TGF-ß/Smad2/3 signaling pathway within the ischemic brain. Furthermore, enriched TGF-ß1 in EVs secreted from OGD-preconditioned microglia stimulated M2 polarization of residing microglia within the ischemic cerebral environment, which may contribute to a regulation of an early inflammatory response in postischemic hemispheres. These observations are not only interesting from the mechanistic point of view but have an immediate therapeutic implication as well, since stroke mice treated with such EVs displayed a better functional recovery in the behavioral test analyses. Hence, the present findings suggest a new way of action of EVs derived from OGD-preconditioned microglia by regulating the TGF-ß/Smad2/3 pathway in order to promote tissue regeneration and neurological recovery in stroke mice.

Inhibition of Fatty Acid Synthesis Aggravates Brain Injury, Reduces Blood-Brain Barrier Integrity and Impairs Neurological Recovery in a Murine Stroke Model.

Inhibition of fatty acid synthesis (FAS) stimulates tumor cell death and reduces angiogenesis. When SH-SY5Y cells or primary neurons are exposed to hypoxia only, inhibition of FAS yields significantly enhanced cell injury. The pathophysiology of stroke, however, is not only restricted to hypoxia but also includes reoxygenation injury. Hence, an oxygen-glucose-deprivation (OGD) model with subsequent reoxygenation in both SH-SY5Y cells and primary neurons as well as a murine stroke model were used herein in order to study the role of FAS inhibition and its underlying mechanisms. SH-SY5Y cells and cortical neurons exposed to 10 h of OGD and 24 h of reoxygenation displayed prominent cell death when treated with the Acetyl-CoA carboxylase inhibitor TOFA or the fatty acid synthase inhibitor cerulenin. Such FAS inhibition reduced the reduction potential of these cells, as indicated by increased NADH2 +/NAD+ ratios under both in vitro and in vivo stroke conditions. As observed in the OGD model, FAS inhibition also resulted in increased cell death in the stroke model. Stroke mice treated with cerulenin did not only display increased brain injury but also showed reduced neurological recovery during the observation period of 4 weeks. Interestingly, cerulenin treatment enhanced endothelial cell leakage, reduced transcellular electrical resistance (TER) of the endothelium and contributed to poststroke blood-brain barrier (BBB) breakdown. The latter was a consequence of the activated NF-κB pathway, stimulating MMP-9 and ABCB1 transporter activity on the luminal side of the endothelium. In conclusion, FAS inhibition aggravated poststroke brain injury as consequence of BBB breakdown and NF-κB-dependent inflammation.

Adipose-derived mesenchymal stem cells reduce autophagy in stroke mice by extracellular vesicle transfer of miR-25.

Grafted mesenchymal stem cells (MSCs) yield neuroprotection in preclinical stroke models by secreting extracellular vesicles (EVs). The neuroprotective cargo of EVs, however, has not yet been identified. To investigate such cargo and its underlying mechanism, primary neurons were exposed to oxygen-glucose-deprivation (OGD) and cocultured with adipose-derived MSCs (ADMSCs) or ADMSC-secreted EVs. Under such conditions, both ADMSCs and ADMSC-secreted EVs significantly reduced neuronal death. Screening for signalling cascades being involved in the interaction between ADMSCs and neurons revealed a decreased autophagic flux as well as a declined p53-BNIP3 activity in neurons receiving either treatment paradigm. However, the aforementioned effects were reversed when ADMSCs were pretreated with the inhibitor of exosomal secretion GW4869 or when Hrs was knocked down. In light of miR-25-3p being the most highly expressed miRNA in ADMSC-EVs interacting with the p53 pathway, further in vitro work focused on this pathway. Indeed, a miR-25-3p oligonucleotide mimic reduced cell death, whereas the anti-oligonucleotide increased autophagic flux and cell death by modulating p53-BNIP3 signalling in primary neurons exposed to OGD. Likewise, native ADMSC-EVs but not EVs obtained from ADMSCs pretreated with the anti-miR-25-3p oligonucleotide (ADMSC-EVsanti-miR-25-3p) confirmed the aforementioned in vitro observations in C57BL/6 mice exposed to cerebral ischemia. The infarct size was reduced, and neurological recovery was increased in mice treated with native ADMSC-EVs when compared to ADMSC-EVsanti-miR-25-3p. ADMSCs induce neuroprotection by improved autophagic flux through secreted EVs containing miR-25-3p. Hence, our work uncovers a novel key factor in naturally secreted ADMSC-EVs for the regulation of autophagy and induction of neuroprotection in a preclinical stroke model.

USP5 promotes epithelial-mesenchymal transition by stabilizing SLUG in hepatocellular carcinoma.

Rationale: The role of SLUG in epithelial-mesenchymal transition during tumor progression has been thoroughly studied, but its precise regulation remains poorly explored. Methods: The affinity purification, mass spectrometry and CO-IP were performed to identify the interaction between SLUG and ubiquitin-specific protease 5 (USP5). Cycloheximide chase assays and deubiquitination assays confirmed that the effect of USP5 on the deubiquitin of SLUG. The dual-luciferase reporter and chromatin immunoprecipitation assays were employed to observe the direct transcriptional regulation of E-cadherin by SLUG effected by USP5. EMT related markers was detected by western blotting and immunofluorescence. Molecular docking, SPR sensor (biacore) and co-location were detected to prove Formononetin targets USP5. Bioinformatics analysis was used to study the relation of USP5 and SLUG to malignancy degree of HCC. Cell migration, invasion in HCC cells and xenografts model in nude mouse were conducted to detect the promotion of USP5 and the inhibition of Formononetin on EMT. Results: USP5 interacts with and stabilizes SLUG to regulate its abundance through USP5 deubiquitination activities in epithelial-mesenchymal transition (EMT) of hepatocellular carcinoma (HCC). USP5 is highly expressed and positively correlated with SLUG expression in HCC with high malignancy. Knockdown of USP5 inhibits SLUG deubiquitination and inhibits HCC cells proliferation, metastasis, and invasion, while overexpression of USP5 promotes SLUG stability and EMT in vitro and in vivo. Through virtual screening, we found that Formononetin exhibits excellent binding to USP5. Moreover, Formononetin inhibits deubiquitinating activities of USP5 to SLUG and consequently impedes the EMT and malignant progression of HCC. Conclusion: Our findings reveal that USP5 serve as a potential target for tumor intervention and provide a preliminary antitumor therapy for inhibit EMT by targeting USP5 or its interaction with SLUG in HCC.

Apigenin inhibits colonic inflammation and tumorigenesis by suppressing STAT3-NF-κB signaling.

Apigenin is a naturally occurring compound with anti-inflammatory, antioxidant, and anticancer properties. Here, we investigated the effects of apigeninin inflammatory bowel disease (IBD) and colitis-associated cancer (CAC). Apigenin effectively inhibited ulcerative colitis, a type of IBD, and CAC. Apigenin decreased myeloperoxidase (MPO), inflammatory cytokine and COX-2 levels, and it attenuated inflammatory cell infiltration in treated colon tissues as compared to untreated model colon tissues. Apigenin also reduced NF-κB and STAT3 activity in vitro and in vivo, thereby inhibiting inflammation and inflammation-induced carcinogenesis. Thus apigenin appears to inhibit inflammation and inflammation-induced carcinogenesisin IBD and CAC by suppressing STAT3-NF-κB signaling.

Sesquiterpene binding Gly-Leu-Ser/Lys-"co-adaptation pocket" to inhibit lung cancer cell epithelial-mesenchymal transition.

Sesquiterpene lactones (SL) have a wide range of applications in anti-tumor and anti-inflammatory therapy. However, the pharmacological mechanism of such substances is not clear. In this study, parthenolide (PTL) was used as an example to explore the anti-tumor effect of natural molecules and their common mechanism. We showed that PTL inhibited the proliferation and migration by reverse EMT via the ERK2/NF-κB/Snail pathway in vivo and in vitro. Interestingly, Multiple potential targets of PTL contain a Gly-Leu-Ser/Lys-"co-adaptation pocket". This inspiring us analogies of PTL may also bind to these target proteins and play a similar function. Significantly, the Concept of co-adaptation pocket may help to increase the selectivity of drug research and development.

Sub-Minimum Inhibitory Concentrations of Rhubarb Water Extracts Inhibit Streptococcus suis Biofilm Formation.

Streptococcus suis is one of the most important swine pathogens, which can cause persistent infection by forming biofilms. In this study, sub-minimum inhibitory concentration (sub-MIC) of rhubarb water extracts were found to inhibit biofilm formation. Two-component signal transduction systems (TCSs), transcriptional regulators, and DNA binding proteins were compared under two conditions: (1) cells treated with sub-MIC rhubarb water extracts and (2) untreated cells. Using an isobaric tags for relative and absolute quantitation (iTRAQ) strategy, we found that TCSs constituent proteins of histidine kinase and response regulator were significantly down-regulated. This down-regulation can affect the transfer of information during biofilm formation. The transcriptional regulators and DNA binding proteins that can interact with TCSs and interrupt gene transcription were also significantly altered. For these reasons, the levels of protein expressions varied in different parts of the treated vs. untreated cells. In summary, rhubarb water extracts might serve as potential inhibitor for the control of S. suis biofilm formation. The change in TCSs, transcriptional regulators, and DNA binding proteins may be important factors in S. suis biofilm inhibition.

Phenytoin silver: a new nanocompound for promoting dermal wound healing via comprehensive pharmacological action.

Phenytoin, an antiepileptic drug, has been widely used for wound healing. Inspired by previous studies, phenytoin silver (PnAg), a sparingly soluble silver nanocompound, was synthesized which exhibited good therapeutic efficacy in tissue repair with low toxicity (LD50 >5 g/kg). In vivo studies showed that PnAg could accelerate dermal wound healing and strong inflammation control in Sprague-Dawley rats (SD rat) and Bama minipigs. Due to its low solubility, PnAg led to low toxicity and blood enrichment in animals. Furthermore, PnAg could upregulate the promoter activity of Jak, Stat3, and Stat3 downstream proteins. Therefore, PnAg may serve as an effective therapeutic compound for wound healing through regulating the gp130/Jak/Stat3 signaling pathway.

Dihydroartemisinin attenuates autoimmune thyroiditis by inhibiting the CXCR3/PI3K/AKT/NF-κB signaling pathway.

Dihydroartemisinin (DHA) is the first generation of naturally occurring artemisinin derivatives with antimalarial activity. Recent research showed that this drug also features immunosuppressive and anti-inflammatory properties. Autoimmune thyroiditis (AIT) is a common organ-specific autoimmune disease with no available effective drug treatment. In this study, we investigated effects of DHA on AIT in vitro and in vivo. Results showed that DHA can visibly reduce antithyroglobulin antibody and thyroid peroxidase antibody levels and regulate T helper cells (Th) 1/Th2 imbalance of experimental AIT mice. DHA also dose-dependently suppressed proliferation of lymphocytes induced by lipopolysaccharide and concanavalin A. DHA inhibited binding of C-X-C chemokine ligand 10 (CXCL10) and its receptor (C-X-C motif) receptor 3 (CXCR3), thus inhibiting calcium flow. DHA can also reduce expression levels of PI3-kinase (PI3K), p-PI3K, protein kinase B (AKT), p-AKT, nuclear factor (NF)-κB/p65, and p-NF-κB/p65. In conclusion, DHA may serve as treatment drug for AIT by inhibiting the CXCR3/PI3K/AKT/NF-kB signaling pathway.

Docetaxel prodrug liposomes for tumor therapy: characterization, in vitro and in vivo evaluation.

There is a strong desire to develop docetaxel (DTX) formulation with good therapeutic effectiveness in view of serious adverse reactions of the commercial formulation of DTX (Taxotere®). In this study, a redox-responsive DTX-vitamin E prodrug was successfully formulated into liposomes with the drug loading of 4.14% ± 0.10%. Compared with DTX liposomes, the DTX prodrug liposomes (DPLs) showed good stability for 30-d shelf life and during dilution with different media. In vitro antitumor activity of DPLs on human prostatic carcinoma PC-3 cells and human lung cancer A549 cells was evaluated using cytotoxicity and apoptosis assays. In spite of a decrease in in vitro antitumor activity, the in vivo pharmacokinetic study reveals that DPLs exhibit significantly longer DTX plasma half-life (t1/2, 1.38-fold) and higher bioavailability (AUC0-t, 14.49-fold) compared with DTX liposomes. The antitumor activity of DPLs to the A549 tumor xenograft model showed selective accumulation in tumor tissue, significant inhibition the growth of the tumors and a much lower toxicity as seen in body weight loss, compared with DTX-Solution. Taken together, the results showed that DPLs is a promising strategy for DTX antitumor delivery.

Improved oral absorption of doxorubicin by amphiphilic copolymer of lysine-linked ditocopherol polyethylene glycol 2000 succinate: in vitro characterization and in vivo evaluation.

In the previous study, we have synthesized an amphiphilic copolymer of nanostructure-forming material and P-glycoprotein (P-gp) inhibitor, lysine-linked ditocopherol polyethylene glycol 2000 succinate (PLV2K). The cytotoxicty in vitro and anticancer efficacy in vivo after intravenous administration of DOX-loaded PLV2K micelles (PLV2K-DOX) was found more effective than DOX solution (DOX-Sol). However, its performance and mechanism on oral absorption of doxorubicin are not well understood yet. PLV2K-DOX are spherical micelles with a narrow size distribution of 20.53 ± 2.44 nm. With an in situ intestinal perfusion model, the intestinal absorption potential of PLV2K-DOX was evaluated in comparison with DOX-Sol. PLV2K-DOX was specifically absorbed in duodenum and ileum sites of rats after oral administration. The intestinal absorption rate (Ka) of PLV2K-DOX is 3.19-, 1.61-, and 1.80-fold higher than that of DOX-Sol in duodenum, jejunum, and ileum, respectively. In Caco-2 uptake studies, PLV2K-DOX micelles significantly improve the internalized amount of DOX by P-gp inhibition of free PLV2K copolymer and endocytosis of DOX-loaded nanoparticles. Moreover, PLV2K-DOX micelles improve the membrane permeability of DOX by multiple transcytosis mechanisms, including caveolin-, clathrin-dependent, and caveolin-/clathrin-independent transcytosis in Caco-2 transport studies. However, the transepithelia electrical resistance (TEER) of Caco-2 cellular monolayer is not changed, suggesting no involvement of paracellular transport of PLV2K-DOX. In vivo pharmacokinetics in rats following oral administration demonstrated that PLV2K-DOX demonstrates higher AUC (5.6-fold) and longer t1/2 (1.2-fold) than DOX-Sol. The findings suggest the new PLV2K micelles might provide an effective nanoplatform for oral delivery of anticancer drugs with poor membrane permeability and low oral bioavailability.

Nanomicelles based on X-shaped four-armed peglyated distearylglycerol as long circulating system for doxorubicin delivery.

A novel X-shaped four-armed gemini-like peglyated distearylglycerol (Gemini-PEG2K-GCDS), with two hydrophilic PEG heads and two hydrophobic stearic acid tails, was successfully synthesized and used as a nanomicellar carrier for delivery of doxorubicin. The critical micelle concentration of the amphiphilic copolymer was higher than 10(-6). Mean particle size and zeta potential of DOX-encapsulated Gemini-PEG2K-GCDS nanomicelles (DOX-GNMs) was 20.4nm and+3.91mv, respectively. Encapsulation efficiency of DOX-GNMs was as high as 94.6 and DOX release was pH-dependent from DOX-GNMs, ensuring the stability of nanomicelles in blood circulation and rapid release of DOX in tumor cells. Pharmacokinetic studies in rats following i.v. administration, DOX-GNMs demonstrated longer retention in blood and larger AUC (19.1-fold of t1/2 and 12.9-fold of AUC) compared with DOX solutions (DOX-Sol). Tissue distribution studies indicate that DOX-GNMs had higher tumor accumulation (4.6-fold) and lower heart toxicity in H22 tumor-bearing mice (17.4-fold) at 48h after administration in comparison with DOX-Sol. Moreover, IC50 of DOX-GNMs increased by 3.3-fold, 2.0-fold and 2.3-fold compared with DOX-Sol in P-gp over-expressing MCF-7/Adr cells after 24h, 48h and 72h, internalized via macropinocytosis-mediated and clathrin-mediated endocytosis. This study suggests that Gemini-PEG2K-GCDS nanomicelle is a promising long circulating delivery system for anti-tumor drugs via extended blood circulation and improved tumor distribution.

Stealth CD44-targeted hyaluronic acid supramolecular nanoassemblies for doxorubicin delivery: probing the effect of uncovalent pegylation degree on cellular uptake and blood long circulation.

Stealth active targeting nanoparticles (NPs) usually include two types of ligand sites: ligand anchored on distal ends of the polyethylene glycol (PEG) and ligand buried under pegylated layer. The latter typical case is hyaluronic acid (HA)-based NPs; however, there is little information available for the latter NPs about effect of the optimal density of surface PEG coating on the blood circulation time, cellular uptake and in vivo anticancer activity. Thus, in this study, in order to optimize the anticancer effects of HA-based NPs, we focus on how uncovalent pegylation degree modulates blood circulation time and cellular uptake of HA-based NPs. We firstly designed a new double-hydrophilic copolymer by conjugating HP-ß-cyclodextrin with HA, and this carrier was further pegylated with adamantyl-peg (ADA-PEG) to form inclusion complex HA-HPCD/ADA-PEG, termed as HCPs. The supramolecular nanoassemblies were fabricated by host-guest and polar interactions between HCPs and doxorubicin (Dox), with vitamin E succinate (VES) being a nanobridge. Despite the active recognition between HA and CD44 receptor, the cellular uptake and targeting efficiency of HA-NPs decreased with the increasing peg density, demonstrating HA was partly buried by high density peg coating. However, the high density of peg coating was beneficial to long circulation time, tumor biodistribution and anticancer activity in vivo. NPs with 5% peg coating had the optimal cellular targeting efficiency in vitro and anticancer effects in vivo. The findings suggest that balancing long circulation property and cellular uptake is important to achieve the optimal antitumor efficacy for pegylated HA-based NPs, and that PEG coating densities cannot be extended beyond a certain density for shielding effect without compromising the efficacy of hyaluronic acid targeted delivery.

Star-shape redox-responsive PEG-sheddable copolymer of disulfide-linked polyethylene glycol-lysine-di-tocopherol succinate for tumor-triggering intracellular doxorubicin rapid release: head-to-head comparison.

A redox-responsive poly(ethylene glycol) (PEG)-sheddable copolymer of disulfide-linked PEG 5000-lysine-di-tocopherol succinate (P(5k)SSLV) is developed which can self-assemble into nanomicelles in aqueous condition and trigger the rapid release of encapsulated drugs within tumor cells. The reduction-insensitive doxorubicin (DOX)-loaded P(5k)LV (P(5k)LV-DOX) nanomicelles are further prepared. Then head-to-head comparison of P(5k)SSLV-DOX, P(5k)LV-DOX and DOX-Sol is performed concerning in vitro release, cytotoxicity, cellular uptake and apoptosis. Results show that P(5k)SSLV-DOX nanomicelles have a faster DOX release, a higher anti-tumor activity and more DOX concentrating in the nucleus than P(5k)LV-DOX nanomicelles. In conclusion, the redox-responsive P(5k)SSLV nanomicelles might hold a great potential to improve chemotherapy by tumor-triggering intracellular rapid release. The outcomes of this study also address the significance of such head-to-head comparison studies in translational research of nanomedicine.

PEG-stabilized bilayer nanodisks as carriers for doxorubicin delivery.

Spherical nanoparticles as a classic delivery vehicle for anticancer drugs have been extensively investigated, but study on the shape of nanoparticles has received little attention until now. Here, a nonspherical poly(ethylene glycol) (PEG)-stabilized bilayer nanodisk consisting of 1,2-distearyl-sn-glycero-3-phosphocholine (DSPC) and PEG5000-glyceryl distearate (PEG5K-GCDS) was prepared for doxorubicin delivery, called DOX-Disks. The prepared disks were open bilayer structures, with a hydrophobic discoid center built by DSPC and a hydrophilic PEG edge. Mean particle diameter of the disk was 80.14 nm, and the disk height was about 6 nm with aspect ratio about 12. Encapsulation efficiency of DOX-Disks was as high as 96.1%, and DOX release from DOX-Disks was pH-dependent (25.6% of total DOX released at 24 h in pH 7.4). The pharmacokinetic performances showed that DOX-Disks demonstrated long circulation time in blood and larger AUC (11.7-fold of t1/2 and 31.7-fold of AUC) in rats compared with DOX solutions (DOX-Sol). Tissue distribution in H22 tumor bearing mice demonstrated higher tumor accumulation (9.7-fold) and lower heart toxicities (25.7-fold) at 48 h after iv administration, in comparison with DOX-Sol. In addition, DOX-Disks exhibited much effectiveness in inhibiting tumor cell growth, and the IC50 values were 2.03, 0.85, and 0.86 µg/mL for DOX-Sol and 0.23, 0.24, and 0.20 µg/mL for DOX-Disks after treatment for 48, 72, and 96 h against MCF-7/Adr cells, respectively. DOX-Disks were taken up into MCF-7/Adr cells via energy-dependent endocytosis processes, involved in clathrin-mediated, macropinocytosis-mediated, and non-clathrin- and non-caveolae-mediated endocytosis pathways. In summary, such PEG-stabilized bilayer nanodisks could be one of the promising carriers for antitumor drugs via extended blood circulation and improved tumor distribution.