Paclitaxel/hydroxypropyl-ß-cyclodextrin complex-loaded liposomes for overcoming multidrug resistance in cancer chemotherapy.

Multidrug resistance (MDR) is the largest obstacle to the success of chemotherapy. The development of innovative strategies and safe sensitizers is required to overcome MDR. Paclitaxel (PTX) is a widely used chemotherapeutic drug, the application of which has been learn to understand MDR. However, the application and use are severely restricted because of this MDR. Cyclodextrins (CDs) of many carriers, additionally have shown anti-cancer capability in MDR cancer cells. In this study, novel paclitaxel/hydroxypropyl-ß-cyclodextrin complex-loaded liposomes (PTXCDL) have been developed in an attempt to overcome MDR in a PTX-resistant human lung adenocarcinoma (A549/T) cell line. The in vitro application of PTXCDL exhibited pH-sensitive PTX release, potent cytotoxicity, and enhanced intracellular accumulation. In comparison to in vivo, PTXCDL also show a stronger inhibition of tumor growth. In comparison, these findings suggest that the PTXCDL provide a novel strategy for effective therapy of resistant cancers by overcoming the drug resistance.

Combinational protective therapy for spinal cord injury medicated by sialic acid-driven and polyethylene glycol based micelles.

Spinal cord injury (SCI) leads to immediate disruption of neuronal membranes and loss of neurons, followed by extensive secondary injury process. Treatment of SCI still remains a tremendous challenge clinically. Minocycline could target comprehensive secondary injury via anti-inflammatory, anti-oxidant and anti-apoptotic mechanisms. Polyethylene glycol (PEG), a known sealing agent, is able to seal the damaged cell membranes and reduce calcium influx, thereby exerting neuroprotective capacity. Here, an E-selectin-targeting sialic acid - polyethylene glycol - poly (lactic-co-glycolic acid) (SAPP) copolymer was designed for delivering hydrophobic minocycline to achieve combinational therapy of SCI. The obtained SAPP copolymer could self-assemble into micelles with critical micelle concentration being of 13.40 µg/mL, and effectively encapsulate hydrophobic minocycline. The prepared drug-loaded micelles (SAPPM) displayed sustained drug release over 72 h, which could stop microglia activation and exhibited excellent neuroprotective capacity in vitro. The SAPP micelles were efficiently accumulated in the lesion site of SCI rats via the specific binding between sialic acid and E-selectin. Due to the targeting distribution and combinational effect between PEG and minocycline, SAPPM could obviously reduce the area of lesion cavity, and realize more survival of axons and myelin sheaths from the injury, thus distinctly improving hindlimb functional recovery of SCI rats and conferring superior therapeutic effect in coparison with other groups. Our work presented an effective and safe strategy for SCI targeting therapy. Besides, neuroprotective capacity of PEG deserves further investigation on other central nervous system diseases.

Polycaprolactone/polysialic acid hybrid, multifunctional nanofiber scaffolds for treatment of spinal cord injury.

Scaffold-based tissue engineering is widely used for spinal cord injury (SCI) treatment by creating supporting and guiding neuronal tissue regeneration. However, how to enhance the axonal regeneration capacity following SCI still remains a challenge. Polysialic acid (PSA), a natural, biodegradable polysaccharide, has been increasingly explored for controlling central nervous system (CNS) development by regulating cell adhesive properties and promoting axonal growth. Here, a polycaprolactone (PCL)/PSA hybrid nanofiber scaffold encapsulating glucocorticoid methylprednisolone (MP) is developed for SCI treatment. Rat models with spinal cord transection is established and the PCL/PSA/MP scaffold is transplanted into lesion area. PCL/PSA/MP scaffold decreases tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) release by inhibiting ionized calcium-binding adapter molecule 1 (Iba1) positive microglia/macrophage activation and reduces apoptosis-associated Caspase-3 protein expression. In addition, the PCL/PSA/MP scaffold inhibits axonal demyelination and glial fibrillary acidic protein (GFAP) expression, increases neurofilament 200 (NF-200) expression and improves functional outcome by Basso, Beattie and Bresnahan (BBB) test. These results demonstrate the therapeutic potential of PSA hybrid nanofiber scaffold in promoting axonal growth and enhancing the functional recovery following SCI. STATEMENT OF SIGNIFICANCE: Scaffold-based tissue engineering is widely used for spinal cord injury (SCI) treatment by creating supporting and guiding neuronal tissue regeneration. And how to enhance the axonal regeneration capacity following SCI still remains a challenge. Polysialic acid (PSA), a natural, biodegradable polysaccharide, has been increasingly explored for controlling central nervous system (CNS) development by regulating cell adhesive properties and promoting axonal growth. However, in vivo therapeutic effect of PSA scaffolds towards SCI is still lack of evidence and needs to be further explored. In this study, a novel electrospun polycaprolactone/PSA scaffold loaded with methylprednisolone (MP) was developed to achieve efficient therapeutic effects towards SCI. And we believe that it broadens the application of PSA for SCI treatment.

E-selectin-targeted Sialic Acid-PEG-dexamethasone Micelles for Enhanced Anti-Inflammatory Efficacy for Acute Kidney Injury.

The effective treatment for acute kidney injury (AKI) is currently limited, and care is primarily supportive. Sialic acid (SA) is main component of Sialyl Lewisx antigen on the mammalian cell surface, which participates in E-selectin binding. Therefore, dexamethasone(DXM)-loaded E-selectin-targeting sialic acid-polyethylene glycol-dexamethasone (SA-PEG-DXM/DXM) conjugate micelles are designed for ameliorating AKI. The conjugates are synthesized via the esterification reaction between PEG and SA or DXM, and can spontaneously form micelles in an aqueous solution with a 65.6 µg/mL critical micelle concentration. Free DXM is incorporated into the micelles with 6.28 ± 0.21% drug loading content. In vitro DXM release from SA-PEG-DXM/DXM micelles can be prolonged to 48h. Much more SA-PEG-DXM micelles can be internalized by lipopolysaccharide (LPS)-activated human umbilical vein endothelial cells (HUVECs) in comparison to PEG-DXM micelles due to specific interaction between SA and E-selectin expressed on HUVECs, and consequently more SA-PEG-DXM micelles are accumulated in the kidney of AKI murine model. Furthermore, SA in SA-PEG-DXM conjugates can significantly ameliorate LPS-induced production of pro-inflammatory cytokines via suppressing LPS-activated Beclin-1/Atg5-Atg12-mediated autophagy to attenuate toxicity. Compared with free DXM and PEG-DXM/DXM micelles, SA-PEG-DXM/DXM micelles show better therapeutical effects, as reflected by the improved renal function, histopathological changes, pro-inflammatory cytokines, oxidative stress and expression of apoptotic related proteins.

Mild microwave activated, chemo-thermal combinational tumor therapy based on a targeted, thermal-sensitive and magnetic micelle.

The development of combinational anti-tumor therapy is of great value. Here, the thermal-sensitive and hepatic tumor cell targeting peptide-A54 modified polymer, A54-poly(ethylene glycol)-g-poly(acrylamide-co-acrylonitrile) (A54-PEG-g-p(AAm-co-AN)) can self-assemble into an 80 nm-sized micelle, which shows a thermal-sensitive behavior with an upper critical solution temperature (UCST) of 43 °C. This self-assembled and targeted A54-PEG-g-p(AAm-co-AN) micelle can co-encapsulate anti-tumor drug doxorubicin (DOX) and magnetic nanoparticles (MNPs) taking advantage of the hydrophobic core of the core-shell micellar structure, when the temperature is lower than 43 °C. A much higher accumulation of the MNPs@A54-PEG-g-p(AAm-co-AN) to the tumor navigated by the A54 targeting peptide is achieved. Due to the thermal-agent effect of the accumulated MNPs in tumor, the mild microwave (8 W) applied afterwards specifically elevates the local tumor temperature by 13 °C, compared to 6 °C without MNPs accumulation in 30 min. The greater temperature rise resulted from the thermal-agent effect of MNPs doesn't only activate the drug release inside tumor cells, but also achieve an augmented hyperthermia. A mild microwave activated, chemo-thermal combinational tumor therapy is thus developed.

Sialic acid-modified solid lipid nanoparticles as vascular endothelium-targeting carriers for ischemia-reperfusion-induced acute renal injury.

In an attempt to improve therapeutic efficacy of dexamethasone (DXM)-loaded solid lipid nanoparticles (NPs) for renal ischemia-reperfusion injury (IRI)-induced acute renal injury (AKI), sialic acid (SA) is used as a ligand to target the inflamed vascular endothelium. DXM-loaded SA-conjugated polyethylene glycol (PEG)ylated NPs (SA-NPs) are prepared via solvent diffusion method and show the good colloidal stability. SA-NPs reduce apoptotic human umbilical vein endothelial cells (HUVECs) via downregulating oxidative stress-induced Bax, upregulating Bcl-xL, and inhibiting Caspase-3 and Caspase-9 activation. Cellular uptake results suggest SA-NPs can be specifically internalized by the inflamed vascular endothelial cells (H2O2-pretreated HUVECs), and the mechanism is associated with the specific binding between SA and E-selectin receptor expressed on the inflamed vascular endothelial cells. Bio-distribution results further demonstrated the enhanced renal accumulation of DXM is achieved in AKI mice treated with SA-NPs, and its content is 2.70- and 5.88-fold higher than those treated with DXM and NPs at 6 h after intravenous administration, respectively. Pharmacodynamic studies demonstrate SA-NPs effectively ameliorate renal functions in AKI mice, as reflected by improved blood biochemical indexes, histopathological changes, oxidative stress levels and pro-inflammatory cytokines. Moreover, SA-NPs cause little negative effects on lymphocyte count and bone mineral density while DXM leads to severe osteoporosis. It is concluded that SA-NPs provide an efficient and targeted delivery of DXM for ischemia-reperfusion-induced injury-induced AKI, with improved therapeutic outcomes and reduced adverse effects.

Multifunctional SPIO/DOX-loaded A54 Homing Peptide Functionalized Dextran-g-PLGA Micelles for Tumor Therapy and MR Imaging.

Specific delivery of chemotherapy drugs and magnetic resonance imaging (MRI) contrast agent into tumor cells is one of the issues to highly efficient tumor targeting therapy and magnetic resonance imaging. Here, A54 peptide-functionalized poly(lactic-co-glycolic acid)-grafted dextran (A54-Dex-PLGA) was synthesized. The synthesized A54-Dex-PLGA could self-assemble to form micelles with a low critical micelle concentration of 22.51 µg. mL-1 and diameter of about 50 nm. The synthetic A54-Dex-PLGA micelles can encapsulate doxorubicin (DOX) as a model anti-tumor drug and superparamagnetic iron oxide (SPIO) as a contrast agent for MRI. The drug-encapsulation efficiency was about 80% and the in vitro DOX release was prolonged to 72 hours. The DOX/SPIO-loaded micelles could specifically target BEL-7402 cell line. In vitro MRI results also proved the specific binding ability of A54-Dex-PLGA/DOX/SPIO micelles to hepatoma cell BEL-7402. The in vivo MR imaging experiments using a BEL-7402 orthotopic implantation model further validated the targeting effect of DOX/SPIO-loaded micelles. In vitro and in vivo anti-tumor activities results showed that A54-Dex-PLGA/DOX/SPIO micelles revealed better therapeutic effects compared with Dex-PLGA/DOX/SPIO micelles and reduced toxicity compared with commercial adriamycin injection.

Endogenous Polysialic Acid Based Micelles for Calmodulin Antagonist Delivery against Vascular Dementia.

Clinical treatment for vascular dementia still remains a challenge mainly due to the blood-brain barrier (BBB). Here, a micelle based on polysialic acid (PSA), which is a hydrophilic and endogenous carbohydrate polymer, was designed to deliver calmodulin antagonist for therapy of vascular dementia. PSA was first chemically conjugated with octadecylamine (ODA), and the obtained PSA-ODA copolymer could self-assemble into micelle in aqueous solution with a 120.0 µg/mL critical micelle concentration. The calmodulin antagonist loaded PSA-ODA micelle, featuring sustained drug release behavior over a period of 72 h with a 3.6% (w/w) drug content and a 107.0 ± 4.0 nm size was then fabricated. The PSA-ODA micelle could cross the BBB mainly via active endocytosis by brain endothelial cells followed by transcytosis. In a water maze test for spatial learning, calmodulin antagonist loaded PSA-ODA micelle significantly reduced the escape latencies of right unilateral common carotid arteries occlusion (rUCCAO) mice with dosage significantly reduced versus free drug. The decrease of hippocampal phospho-CaMKII (Thr286/287) and phospho-synapsin I (Ser603) was partially restored in rUCCAO mice following calmodulin antagonist loaded PSA-ODA micelle treatment. Consistent with the restored CaMKII phosphorylation, the elevation of BrdU/NeuN double-positive cells in the same context was also observed. Overall, the PSA-ODA micelle developed from the endogenous material might promote the development of therapeutic approaches for improving the efficacy of brain-targeted drug delivery and have great potential for vascular dementia treatment.

Characteristics of sequential targeting of brain glioma for transferrin-modified cisplatin liposome.

Methods on how to improve the sequential targeting of glioma subsequent to passing of drug through the blood-brain barrier (BBB) have been occasionally reported. However, the characteristics involved are poorly understood. In the present study, cisplatin (Cis) liposome (lipo) was modified with transferrin (Tf) to investigate the characteristics of potential sequential targeting to glioma. In bEnd3/C6 co-culture BBB models, higher transport efficiency across the BBB and cytotoxicity in basal C6 cells induced by Cis-lipo(Tf) than Cis-lipo and Cis-solution, suggest its sequential targeting effect. Interestingly, similar liposomal morphology as that of donor compartment was first demonstrated in the receptor solution of BBB models. Meanwhile, a greater acquisition in the lysosome of bEnd3, distributed sequentially into the nucleus of C6 cells were found for the Cis-lipo(Tf). Pre-incubation of chlorpromazine and Tf inhibited this process, indicating that a clathrin-dependent endocytosis is involved in the transport of Cis-lipo(Tf) across the BBB.

Evaluation of pluronic nanosuspensions loading a novel insoluble anticancer drug both in vitro and in vivo.

To improve the solubility, stability and the antitumor activity of a novel anticancer drug, 3-(4-bromopheny l)-2-(ethyl-sulfonyl)-6-methylquinoxaline1,4-dioxide (Q39), a poloxamer nanosuspension was developed by precipitation combined with high pressure homogenization in present study. In vitro characterizations of Q39 nanosuspension (Q39/NS), including particle size, polydispersity index (PI), morphology, crystalline, saturation solubility, stability and releases were evaluated. BABL/c nude mice bearing HepG2 cells were used as in vivo tumor models to evaluate the anti-tumor activity of Q39/NS after intravenous administration. The particle size and PI for Poloxamer188 nanosuspension (P188/NS) were (304±3) nm, and (0.123±0.005) respectively, and it was (307±5) nm and (0.120±0.007) for Poloxamer85 nanosuspension (P85/NS) correspondingly. The morphology of P188/NS was spherical shape while elliptoid shape for P85/NS. The crystalline of Q39/NS did not change as shown by the X-ray diffraction analysis. The stability of Q39/NS improved compared with the solution. The solubility of Q39 in P188/NS was 7.3 times higher than the original solubility, while it was 6 times for P85/NS. Sustained release as shown from the in vitro release test, together with the tumor-targeting as shown from in vivo NS distribution, may contribute to the enhanced in vivo antitumor activity of Q39/NS.

Actively-targeted LTVSPWY peptide-modified magnetic nanoparticles for tumor imaging.

BACKGROUND: Magnetic resonance imaging (MRI) is widely used in modern clinical medicine as a diagnostic tool, and provides noninvasive and three-dimensional visualization of biological phenomena in living organisms with high spatial and temporal resolution. Therefore, considerable attention has been paid to magnetic nanoparticles as MRI contrast agents with efficient targeting ability and cellular internalization ability, which make it possible to offer higher contrast and information-rich images for detection of disease. METHODS: LTVSPWY peptide-modified PEGylated chitosan (LTVSPWY-PEG-CS) was synthesized by chemical reaction, and the chemical structure was confirmed by (1)H-NMR. LTVSPWY-PEG-CS-modified magnetic nanoparticles were prepared successfully using the solvent diffusion method. Their particle size, size distribution, and zeta potential were measured by dynamic light scattering and electrophoretic mobility, and their surface morphology was investigated by transmission electron microscopy. To investigate their selective targeting ability, the cellular uptake of the LTVSPWY-PEG-CS-modified magnetic nanoparticles was observed in a cocultured system of SKOV-3 cells which overexpress HER2 and A549 cells which are HER2-negative. The in vitro cytotoxicity of these nanoparticles in SKOV-3 and A549 cells was measured using the MTT method. The SKOV-3-bearing nude mouse model was used to investigate the tumor targeting ability of the magnetic nanoparticles in vivo. RESULTS: The average diameter and zeta potential of the LTVSPWY-PEG-CS-modified magnetic nanoparticles was 267.3 ± 23.4 nm and 30.5 ± 7.0 mV, respectively, with a narrow size distribution and spherical morphology. In vitro cytotoxicity tests demonstrated that these magnetic nanoparticles were carriers suitable for use in cancer diagnostics with low toxicity. With modification of the LTVSPWY homing peptide, magnetic nanoparticles could be selectively taken up by SKOV-3 cells overexpressing HER2 when cocultured with HER2-negative A549 cells. In vivo biodistribution results suggest that treatment with LTVSPWY-PEG-CS-modified magnetic nanoparticles/DiR enabled tumors to be identified and diagnosed more rapidly and efficiently in vivo. CONCLUSION: LTVSPWY-PEG-CS-modified magnetic nanoparticles are a promising contrast agent for early detection of tumors overexpressing HER2 and further diagnostic application.

Molecular mechanism study of chemosensitization of doxorubicin-resistant human myelogenous leukemia cells induced by a composite polymer micelle.

The present study was aimed to overcome the multidrug resistance (MDR) of tumor cells which accounts for the failure of clinical chemotherapy. A novel doxorubicin (DOX)-loaded composite micelle consisting of polyethylene glycol (PEG)-polycaprolactone (PCL)/Pluronic P105 has been developed and was proved to inhibit the drug resistance of human myelogenous leukemia (K562/ADR) cells. The modulation mechanism that DOX-loaded the composite micelle inhibited MDR was for the first time investigated at cell levels. Results indicated that the cytotoxicity in K562/ADR cells treated by DOX-loaded PEG-PCL/P105 composite micelle was about 4 times higher than DOX solution at 12 µg/mL of DOX. Confocal images showed that the DOX-loaded composite micelles gradually entered into cytoplasm and nucleus, and stayed in intracellular much longer than DOX solution. All the micelles (PEG-PCL micelle, P105 micelle and PEG-PCL/P105 composite micelle) did not change Pgp expression on the surface of K562/ADR cells. However, further study revealed that micelle containing of P105 (P105 or PEG-PCL/P105 composite micelle) significantly decreased ATP level, and consequently restricted the activity of Pgp by down-regulation of mitochondrial membrane potential. On the other hand, the PEG-PCL micelle had no effect on both mitochondrial membrane potential and ATP level of the K562/ADR cells, but its access to K562/ADR cells through endocytic pathway avoided the recognition of Pgp. The PEG-PCL/P105 composite micelle was designed based on the combination of P105-mediated down regulation of mitochondrial membrane potential the malignant cells and PEG-PCL-mediated internalization effect. Therefore, the novel composite micelle is a promising drug delivery system for anticancer drug to overcome MDR.

PAMAM-triamcinolone acetonide conjugate as a nucleus-targeting gene carrier for enhanced transfer activity.

The excellent transfection efficiency and viability are essential for successful gene therapy. It suggested that when bound to its glucocorticoid receptor, glucocorticoid steroid can dilate the nuclear pore complexes and facilitated the transport of pDNA into the nucleus. In this research, the two different degrees of substitution of PAMAM-triamcinolone acetonide (PAMAM-TA) conjugates were synthesised for efficient translocation of pDNA into the nucleus. The physicochemical properties of the polyplexes were investigated by agarose gel electrophoresis, Zeta-sizer and TEM. They both could form nano-size polyplexes with pDNA. The polyplexes were very stable and showed excellent buffering capacities, facilitating endosomal escape, and no obvious difference was found between them. The TA-conjugated PAMAM-mediated transfection of luciferase and EGFP genes showed better transfer activity than native PAMAM and was comparable to the PEI 25K (polyethylenimine), and lower cytotoxicity in HEK 293 and HepG 2 cells. Even with 10% serum, their transfer activity was still high relatively. In addition, confocal microscopy examination confirmed that the enhancing mechanism for enhanced gene transfer activity of PAMAM-TA conjugate may involve the nuclear translocation of the polyplex. The low substituted degree of TA to 0.22 did not interrupt its nuclear localization potency. These findings demonstrated that the TA-grafted PAMAM dendrimer is a potential candidate as a safe and efficient gene delivery carrier for gene therapy.