Self-Reinforced PTLG Copolymer with Shish Kebab Structures and a Bionic Surface as Bioimplant Materials for Tissue Engineering Applications.

Green and biodegradable materials with great mechanical properties and biocompatibility will offer new opportunities for next-generation high-performance biological materials. Herein, the novel oriented shish kebab crystals of a novel poly(trimethylene carbonate-lactide-glycolide) (PTLG) vascular stent are first reported to be successfully fabricated through a feasible solid-state drawing process to simultaneously enhance the mechanical performance and biocompatibility. The crystal structure of this self-reinforced vascular stent was transformed from spherulites to a shish kebab crystal, which indicates the mechanical interlocking effect and prevents the lamellae from slipping with a significant improvement of mechanical strength to 333 MPa. Meanwhile, it is different from typical biomedical polymers with smooth surface structures, and the as-obtained PTLG vascular stent exhibits a bionic surface morphology with a parallel micro groove and ridge structure. These ridges and grooves were attributed to the reorganization of cytoskeleton fiber bundles following the direction of blood flow shear stress. The structure and parameters of these morphologies were highly similar to the inner surface of blood vessels of the human, which facilitates cell adhesion growth to improve its proliferation, differentiation, and activity on the surface of PTLG.

GE11 peptide-decorated acidity-responsive micelles for improved drug delivery and enhanced combination therapy of metastatic breast cancer.

Nanotechnology-mediated drug delivery systems suffer from insufficient retention in tumor tissues and unreliable drug release at specific target sites. Herein, we developed an epidermal growth factor receptor-targeted multifunctional micellar nanoplatform (GE11-DOX+CEL-M) by encapsulating celecoxib into polymeric micelles based on the conjugate of GE11-poly(ethylene glycol)-b-poly(trimethylene carbonate) with doxorubicin to suppress tumor growth and metastasis. The polymeric micelles maintained stable nanostructures under physiological conditions but quickly disintegrated in a weakly acidic environment, which is conducive to controlled drug release. Importantly, GE11-DOX+CEL-M micelles effectively delivered the drug combination to tumor sites and enhanced tumor cell uptake through GE11-mediated active tumor targeting. Subsequently, GE11-DOX+CEL-M micelles dissociated in response to intracellular slightly acidic microenvironmental stimuli, resulting in rapid release of celecoxib and doxorubicin to synergistically inhibit the proliferation and migration of tumor cells. Systemic administration of GE11-DOX+CEL-M micelles into mice bearing subcutaneous 4T1 tumor models resulted in higher tumor growth suppression and decreased lung metastasis of tumor cells compared with micelles without GE11 decoration or delivering only doxorubicin. Furthermore, the micelles effectively reduced the systemic toxicity of the chemotherapy drugs. This nanotherapeutic system provides a promising strategy for safe and effective cancer therapy.

Hierarchical responsive micelle facilitates intratumoral penetration by acid-activated positive charge surface and size contraction.

Integrating these features of acid-activated positively charged surface and size contraction into single nanoparticle would be an effective strategy for enhancing cellular uptake, intratumoral penetration and accumulation. Here, hierarchical responsive micelle (HVDMs) was developed via RAFT reaction as multifunctional polymer-drug conjugate for maximizing penetration and therapeutic effect against MCF-7 tumor by combining positively charged surface with size contraction: surface zeta-potential reversal (-2 to +12 mV) by protonation of PHEME and size contraction (~81-~41 nm) by simultaneous hydrophobic/hydrophilic conversion (pH ≈ 6.7); the disintegration of hydrazone bond between hydrophobic PVB and DOX triggered drug release (pH ≈ 5.0). The in vitro structural stabilization, cellular uptake and anti-proliferative efficiency were significantly higher than other control groups (CVDMs and HSDMs) at pH 6.7. The markedly increased penetration depth, cellular internalization and anti-tumor efficiency were confirmed in 3D MCSs spheroids at pH 6.7, and the ex vivo DOX fluorescence images further verified obvious penetration and accumulation in internal region of solid tumor. The antitumor effect in vivo demonstrated that HVDMs accelerated tumor atrophy, induced intratumoral cells apoptosis and alleviated system toxicity.

Anti-platelet aggregation of Panax notoginseng triol saponins by regulating GP1BA for ischemic stroke therapy.

BACKGROUND: Panax notoginseng triol saponins (PTS) has been used clinically for ischemic stroke therapy (IST) in China for more than 17 years due to its anti-platelet aggregation and neuro-protective effects, but its mechanism of action is not fully understand. In this study, anti-platelet aggregation-related protein analysis and computer simulations of drug-protein binding interactions were performed to explore the mechanism of the effects of PTS against ischemic stroke in an ischemia reperfusion model. METHODS: Three oral doses of PTS were administered in a model of middle cerebral artery occlusion (MCAO) in rats. Panax notoginseng total saponins (PNS) and a combination of PTS and aspirin were chosen for comparison. To evaluate therapeutic effects and explore possible mechanisms of anti-platelet aggregation, we measured cerebral infarct size and water content in brain tissue, histomorphological changes, expression of related factors (such as arachidonic acid metabolites) and platelet receptors in serum, as well as the binding affinity of PTS for platelet adhesion receptors. RESULTS: Compared with PNS, PTS showed a stronger and more potent anti-platelet aggregation effect in MCAO model rats. The combination of PTS and aspirin could reduce adverse gastrointestinal effects by regulating the TXA2/PGI2 ratio. We demonstrated for the first time that PTS was able to regulate Glycoprotein Ib-α (GP1BA) in a model animal. The binding of ginsenoside Rg1 and GP1BA could form a stable structure. Moreover, PTS could reduce von Willebrand factor (VWF)-mediated platelet adhesion to damaged vascular endothelium, and thus enhance the probability of anti-platelet aggregation and anti-thrombosis under pathological conditions. CONCLUSIONS: Our results showed that GP1BA was closely related to the anti-platelet aggregation action of PTS, which provided new scientific and molecular evidence for its clinical application.

Reversing P-Glycoprotein-Associated Multidrug Resistance of Breast Cancer by Targeted Acid-Cleavable Polysaccharide Nanoparticles with Lapatinib Sensitization.

For reversing the treatment failure in P-glycoprotein (P-gp)-associated MDR (multidrug resistance) of breast cancer, a high dose of Lapatinib (Lap), a substrate of breast cancer-resistant protein, was encapsulated into safe and effective acid-cleavable polysaccharide-doxorubicin (Dox) conjugates to form targeted HPP-Dox/Lap nanoparticles with an optimal drug ratio and appropriate nanosize decorated with oligomeric hyaluronic acid (HA) for specially targeting overexpressed CD44 receptors of MCF-7/ADR. The markedly increased cellular uptake and the strongest synergetic cytotoxicity revealed the enhanced reversal efficiency of HPP-Dox/Lap nanoparticles with reversal multiples at 29.83. This was also verified by the enhanced penetrating capacity in multicellular tumor spheroids. The reinforced Dox retention and substantial down-regulation of P-gp expression implied the possible mechanism of MDR reversal. Furthermore, the efficient ex vivo accumulation and distribution of nanoparticles in the tumor site and the high tumor growth inhibition (93%) even at a lower dosage (1 mg/kg) as well as lung metastasis inhibition in vivo with negligible side effects revealed the overwhelming advantages of targeted polysaccharide nanoparticles and Lap-sensitizing effect against drug-resistant tumor. The development of an efficient and nontoxic-targeted polysaccharide delivery system for reversing MDR by synergistic therapy might provide a potential clinical application value.

Lapatinib-loaded acidity-triggered charge switchable polycarbonate-doxorubicin conjugate micelles for synergistic breast cancer chemotherapy.

Stimulus-responsive nanosystem is a powerful method to improve the bioavailability and reduce the side effects of anticancer agents. In the present study, a customized dual pH-responsive micellar nanoplatform (DOX+LAP-M) based on polycarbonate-doxorubicin conjugate micelles was prepared to co-deliver the chemotherapeutic agent lapatinib for inhibiting tumor growth and metastasis. DOX+LAP-M micelles with spherical morphology had a size of ~112 nm and had an initial negative surface charge, which are favorable characteristics for long-term circulation in the blood. Once the micelles accumulated in tumor tissues, the intrinsic tumor extracellular acidity triggered the charge switch of DOX+LAP-M micelles from -1 to 9 mV, thereby facilitating cell internalization and tumor penetration. Subsequently, the pH-sensitive micellar core accelerated the release of doxorubicin and lapatinib in the acidic intracellular environment. DOX+LAP-M micelles effectively inhibited the proliferation, migration, and invasion of 4T1 cells in vitro; furthermore, the administration of DOX+LAP-M micelles in 4T1 xenograft-bearing mice suppressed solid tumor growth with an inhibitory rate of 90.2% and significantly decreased pulmonary metastatic nodules, without significant systemic toxicity. This multifunctional micellar system has high potential for clinical cancer therapy.

pH-Responsive charge switchable PEGylated ε-poly-l-lysine polymeric nanoparticles-assisted combination therapy for improving breast cancer treatment.

Stimuli-responsive nanotechnology-mediated drug co-delivery system is a notable strategy to improve access of the systemically administered chemotherapeutics to the tumors. Herein, a tailor-made 2,3-dimethylmaleic-anhydride-poly(ethylene glycol)-ε-poly-l-lysine-doxorubicin /lapatinib polymeric nanoplatform (DMMA-P-DOX/LAP) for synergistically eliminating breast cancer is developed by encapsulating lapatinib into dual-pH responsive charge switchable biopolymer-doxorubicin conjugate nanoparticles. The physicochemical properties of polymeric nanoparticles are conducive to their stable circulation in the physiological condition, but reverse the surface charge from negative to positive ultrasensitively in slightly acidic tumor microenvironment, facilitating cell internalization and deep tumor penetration. Subsequently, DOX and LAP are synchronously released into the cytoplasm in response to the significantly increased acidity of intracellular environment. As a result, the combination therapy by DMMA-P-DOX/LAP nanoparticles compels the solid tumors to contract significantly or even vanish completely in the MCF-7 tumor model, moreover, the structural composition with amino acid and bioinert PEG ensures the favorable biosecurity of the co-delivery system in vivo. This dual-pH responsive nanotechnology-mediated drug co-delivery system provides great potentials for safe and effective cancer therapy.

Acid-labile polysaccharide prodrug via lapatinib-sensitizing effect substantially prevented metastasis and postoperative recurrence of triple-negative breast cancer.

Surgical resection and chemotherapy are routinely performed for triple-negative breast cancer (TNBC) because it is insensitive to endocrine therapy and molecular targeted therapy. Here, the optimal surface charge (-28 mV) and particle size (51 nm) enabled the acid-labile hyaluronic acid pullulan prodrug (HPP)-doxorubicin (Dox)/lapatinib (Lap) conjugate to circulate in the blood for a lengthy period of time and enhance the electron paramagnetic resonance effect, while the targeted molecule hyaluronic acid accelerated CD44 receptor-mediated 4T1 cell internalization. The inefficient anti-proliferation capability of Lap increased more than 10-fold after sensitization of Dox to metastatic 4T1 cells, while cellular uptake significantly increased, and cell viability dramatically decreased to nearly 20% of the free Dox group. Furthermore, HPP-Dox/Lap more effectively inhibited lateral mobility, vertical migration, and invasion ability of 4T1 cells. The ex vivo biodistribution of representative Dox indicated that Lap obviously facilitated the intratumoral infiltration and accumulation. The in vivo research revealed that there were overwhelming advantages in using HPP-Dox/Lap to inhibit tumor growth, progression, and lung metastasis even at a low dosage (1 mg kg-1), and it decreased postoperative recurrence and pulmonary metastatic nodules. Because of the excellent biosafety and visible therapeutic effect on the 4T1 metastasis and recurrence model, there is great potential value for HPP-Dox/Lap to be used to treat metastatic TNBC.

Reductive responsive micelle overcoming multidrug resistance of breast cancer by co-delivery of DOX and specific antibiotic.

The residual tumor cells after chemotherapy, even in very small numbers, are generally drug-resistant and invasive, which might result in the progress of tumor metastasis and recurrence. In this research, a new combination chemotherapy strategy of salinomycin (SL) that could selectively inhibit multidrug-resistant tumor cells and a traditional broad-spectrum antitumor drug, doxorubicin (DOX), based on redox-degradable nano-micelles was developed to overcome drug resistance in vitro. The results in vitro indicated that DOX + SL co-loaded nano-micelles could not only escape from the drug efflux of adriamycin-resistant MCF-7 cells (A/MCF-7) but also penetrated and infiltrated into 3D-cultured MCF-7 and 4T1 tumor spheres in vitro more effectively, resulting in a strong antiproliferative effect. In the allogeneic metastatic 4T1 tumor model, the combination chemotherapy of DOX + SL encapsulated in nano-micelles effectively suppressed tumor growth with no splenomegaly and no other major tissue damage, and reversed the EMT progress, and inhibited tumor recurrence and metastasis more effectively after drug withdrawal.

Injectable self-crosslinking HA-SH/Col I blend hydrogels for in vitro construction of engineered cartilage.

The injectable self-crosslinking blend hydrogel by combination of collagen I and thiolated hyaluronic acid could alleviate collagen I contraction in vitro and overcome weak cell adhesive sites of hyaluronic acid. Five groups of injectable hydrogels with different ratios were prepared to investigate their gelation time, injection force, mechanical properties, swelling capacity and disintegration performance. These results indicated that Col7HA-SH3 hydrogel achieved the optimal controlled and injectable effect, the gelation time was just ten seconds with injection force at 3.5 N, and the storage modulus of hydrogel could reach 11 kPa with frequency at 10 Hz. Furthermore, the phenotype maintaining, biocompatibility and chondrocytes proliferation were administrated by CLSM, SEM, histological staining, immuohistochemical staining, MTT test and glycoaminoglycans quantification. Similarly, the Col7HA-SH3 blend hydrogel encapsulated chondrocytes presented most excellent proliferation potential, phenotype maintaining, biocompatibility and convenient operational characteristics. These findings might approach the underlying clinical application of blend hydrogel in cartilage repair.

Synergistic chemotherapeutic effect of sorafenib-loaded pullulan-Dox conjugate nanoparticles against murine breast carcinoma.

pH-Sensitive pullulan-doxorubicin conjugates encapsulating sorafenib (P-Dox/S) nanoparticles were developed as a synergistic combinatorial delivery system against murine breast carcinoma. The nanoparticles can encapsulate Dox and sorafenib with ultra-high loading capacity (65.34 wt%) through chemical conjugation and physical loading, whereas can remain stable under physiological conditions and gradually release Dox and sorafenib with the decreasing pH. These conjugates can be effectively internalized and clearly suppress 4T1 cell growth in vitro. Furthermore, research data of in vivo animal models revealed that the synergistic combinatorial P-Dox/S nanoparticles heavily accumulated in solid tumor tissue sites to maximize therapeutic efficacy; they also significantly inhibited solid tumor growth, even remarkably reduced solid tumor volume in comparison to the initial volume, and obviously diminished adverse effects. The anti-tumor therapeutic effect obviously outperformed the delivery of combinational chemotherapy of free drugs or single drug-loaded P-Dox nanoparticles at the same concentration. These promising results indicate the high-efficiency synergistic chemotherapeutic effects of these nanoparticles. Combinational chemotherapy using P-Dox/S nanoparticles has important potential in the clinical treatment of malignancy for overcoming drug resistance and heterogeneity.

Localized multidrug co-delivery by injectable self-crosslinking hydrogel for synergistic combinational chemotherapy.

Significant progress has been made in the use of injectable hydrogels as drug carrier systems to treat cancers by the peritumoral-localized co-delivery of multiple drugs with different therapeutic mechanisms. In this study, a novel, injectable self-crosslinking HA-SH hydrogel was able to concurrently encapsulate multiple drugs (sorafenib, doxorubicin, and metformin) to enhance chemotherapy efficacy. The hydrogel was relatively stable under physiological conditions and could quickly and directly release the loaded drugs to the tumor site in a reductive tumor microenvironment. The in vitro antitumor activity and cell-apoptosis assay demonstrated that the hydrogel loaded with multiple drugs (Gel + DS or Gel + DSM) showed obvious synergistic effects against breast cancer cells. The combinational chemotherapy enhanced the sensitivities of tumor cells and promoted tumor cell apoptosis after peritumoral administration. Compared with the single drug-loaded hydrogel, the hydrogel co-loaded with multiple drugs (Gel + DSM) showed the best tumor growth inhibition. Moreover, the monitoring of mice weight and ex vivo histological analysis of the main organs indicated that localized treatment with the hydrogel co-loaded with multiple drugs (Gel + DSM) obviously relieved the systemic toxicity and showed promise for inhibiting tumor metastasis, suggesting the superiority and potential application prospects of the injectable, self-crosslinking hydrogel co-loaded with multiple drugs.

Reduction-Degradable Polymeric Micelles Decorated with PArg for Improving Anticancer Drug Delivery Efficacy.

In this study, five kinds of reduction-degradable polyamide amine-g-polyethylene glycol/polyarginine (PAA-g-PEG/PArg) micelles with different proportions of hydrophilic and hydrophobic segments were synthesized as novel drug delivery vehicles. Polyarginine not only acted as a hydrophilic segment but also possessed a cell-penetrating function to carry out a rapid transduction into target cells. Polyamide amine-g-polyethylene glycol (PAA-g-PEG) was prepared for comparison. The characterization and antitumor effect of the DOX-incorporated PAA-g-PEG/PArg cationic polymeric micelles were investigated in vitro and in vivo. The cytotoxicity experiments demonstrated that the PAA-g-PEG/PArg micelles have good biocompatibility. Compared with DOX-incorporated PAA-g-PEG micelles, the DOX-incorporated PAA-g-PEG/PArg micelles were more efficiently internalized into human hepatocellular carcinoma (HepG2) cells and more rapidly released DOX into the cytoplasm to inhibit cell proliferation. In the 4T1-bearing nude mouse tumor models, the DOX-incorporated PAA-g-PEG/PArg micelles could efficiently accumulate in the tumor site and had a longer accumulation time and more significant aggregation concentration than those of PAA-g-PEG micelles. Meanwhile, it excellently inhibited the solid tumor growth and extended the survival period of the tumor-bearing Balb/c mice. These results could be attributed to their appropriate nanosize and the cell-penetrating peculiarity of polyarginine as a surface layer. The PAA-g-PEG/PArg polymeric micelles as a safe and high efficiency drug delivery system were expected to be a promising delivery carrier that targeted hydrophobic chemotherapy drugs to tumors and significantly enhanced antitumor effects.

The self-crosslinking smart hyaluronic acid hydrogels as injectable three-dimensional scaffolds for cells culture.

Although the disulfide bond crosslinked hyaluronic acid hydrogels have been reported by many research groups, the major researches were focused on effectively forming hydrogels. However, few researchers paid attention to the potential significance of controlling the hydrogel formation and degradation, improving biocompatibility, reducing the toxicity of exogenous and providing convenience to the clinical operations later on. In this research, the novel controllable self-crosslinking smart hydrogels with in-situ gelation property was prepared by a single component, the thiolated hyaluronic acid derivative (HA-SH), and applied as a three-dimensional scaffold to mimic native extracellular matrix (ECM) for the culture of fibroblasts cells (L929) and chondrocytes. A series of HA-SH hydrogels were prepared depending on different degrees of thiol substitution (ranging from 10 to 60%) and molecule weights of HA (0.1, 0.3 and 1.0 MDa). The gelation time, swelling property and smart degradation behavior of HA-SH hydrogel were evaluated. The results showed that the gelation and degradation time of hydrogels could be controlled by adjusting the component of HA-SH polymers. The storage modulus of HA-SH hydrogels obtained by dynamic modulus analysis (DMA) could be up to 44.6 kPa. In addition, HA-SH hydrogels were investigated as a three-dimensional scaffold for the culture of fibroblasts cells (L929) and chondrocytes cells in vitro and as an injectable hydrogel for delivering chondrocytes cells in vivo. These results illustrated that HA-SH hydrogels with controllable gelation process, intelligent degradation behavior, excellent biocompatibility and convenient operational characteristics supplied potential clinical application capacity for tissue engineering and regenerative medicine.

Efficient Delivery of DOX to Nuclei of Hepatic Carcinoma Cells in the Subcutaneous Tumor Model Using pH-Sensitive Pullulan-DOX Conjugates.

A series of pullulan-doxorubicin conjugates (Pu-DOXs) were investigated for effectively delivering DOX to nuclei of hepatic carcinoma cells in subcutaneous tumor model. These Pu-DOXs were prepared by conjugating DOX onto pullulan molecule via pH-responsive hydrazone bond using spacers with different alkane chain length. The highest drug loading content of Pu-DOXs went up to nearly 50%, and the diameter of Pu-DOX nanoparticles ranged from 50 to 170 nm, as measured by DLS and TEM. These Pu-DOX nanoparticles could rapidly release DOX in the acidic environment at pH = 5.0 while being kept relatively stable in neural conditions. The in vitro cell coculture experiments revealed that these Pu-DOX nanoparticles were selectively internalized by hepatic carcinoma cells through receptor-mediated endocytosis via asialoglycoprotein receptor on the hepatic carcinoma cell surface. DOX was rapidly released from Pu-DOX nanoparticles in acidic endosome/lysosome, diffused into cell nuclei due to its strong affinity to nucleic acid, inhibited the cell proliferation, and accelerated the cell apoptosis. In the nude mice subcutaneous hepatic carcinoma model, Pu-DOX nanoparticles efficiently accumulated in the tumor site through the enhanced permeation and retention effect. Then DOX was specifically internalized by hepatic carcinoma cells and rapidly diffused into the nuclei of cells. Compared with the control group in in vivo experiments, these Pu-DOX nanoparticles effectively inhibited solid tumor growth, prolonging the lifetime of the experimental animal. These pH sensitive nanoparticles might provide an important clinical implication for targeted hepatic carcinoma therapy with high efficiency and low systematic toxicity.