Yifei Lu

Development of chitosan nanoparticles as drug delivery system for a prototype capsid inhibitor

Oral delivery of biopharmaceutics drug disposition classification system (BDDCS) Class II or IV drugs with poor aqueous solubility and poor enzymatic and/or metabolic stability is very challenging. Bay41-4109, a member of the heteroaryldihydropyrimidine (HAP) family, inhibits HBV replication by destabilizing capsid assembly. It pertains to class II of the BDDCS which has a practically insoluble solubility which is 38 μg/mL (LYSA) and the oral delivery resulted in low bioavailability. The purpose of the current research work was to develop and evaluate Bay41-4109 loaded chitosan nanoparticles to increase the solubility and bioavailability for treatment of HBV. The Bay41-4109 nanoparticles were prepared by gelation of chitosan with tripolyphosphate (TPP) through ionic cross-linking. A three-factor three-level central composite design (CCD) was introduced to perform the experiments. A quadratic polynomial model was generated to predict and evaluate the independent variables with respect to the dependent variables. Bay41-4109 was encapsulated in the chitosan nanoparticles were demonstrated by PLM, FTIR, DSC, XRD and TEM etc. The in vivo results suggest that Bay41-4109 nanoparticles have better bioavailability and would be a promising approach for oral delivery of Bay41-4109 for the treatment of HBV.

ROS-Switchable Polymeric Nanoplatform with Stimuli-Responsive Release for Active Targeted Drug Delivery to Breast Cancer

Tumor microenvironment plays a vital role in the process of tumor development, proliferation, invasion, and metastasis. It is well acknowledged that reduction in pH, reactive oxygen species (ROS), and increased level of glucose transporter 1 (GLUT1) have become featured intracellular and extracellular biochemical markers of cancer owing to oncogenic transformation and abnormal metabolism. To establish a distinctive drug delivery system directed against the tumor microenvironment features, we develop a newly engineered polymeric nanoplatform for efficient doxorubicin (DOX) delivery with reduced systemic toxicity and high antitumor efficiency. A thioketal cross-linker is used to improve the formulations stability during circulation and to foster quick intracellular drug release in response to tumors ROS potential. Furthermore, the low drug loading efficiency of conventional micelles is ameliorated in this polymeric nanoplatform via a drug-conjugation strategy with an acid-labile chemical bond. The optimized formulation, MPLs-sB-DOX micelles, possesses a high drug-loading efficiency (31%) within nanosize diameter (37.8 nm). In addition, this formulation shows significant improvement in the pharmacokinetics and biodistribution profiles with a 2.69-fold increase of tumor accumulation, while with largely reduced systemic toxicity in comparison with free DOX. With advantages of efficient cellular uptake, preferential tumor accumulation, and controlled release behaviors, MPLs-sB-DOX micelles demonstrate good tumor-targeting ability with reduced systemic toxicity, proving to be a promising formulation for breast cancer therapy.

Macrophage-Membrane-Coated Nanoparticles for Tumor-Targeted Chemotherapy

Various delivery vectors have been integrated within biologically derived membrane systems to extend their residential time and reduce their reticuloendothelial system (RES) clearance during systemic circulation. However, rational design is still needed to further improve the in situ penetration efficiency of chemo-drug-loaded membrane delivery-system formulations and their release profiles at the tumor site. Here, a macrophage-membrane-coated nanoparticle is developed for tumor-targeted chemotherapy delivery with a controlled release profile in response to tumor microenvironment stimuli. Upon fulfilling its mission of tumor homing and RES evasion, the macrophage-membrane coating can be shed via morphological changes driven by extracellular microenvironment stimuli. The nanoparticles discharged from the outer membrane coating show penetration efficiency enhanced by their size advantage and surface modifications. After internalization by the tumor cells, the loaded drug is quickly released from the nanoparticles in response to the endosome pH. The designed macrophage-membrane-coated nanoparticle (cskc-PPiP/PTX@Ma) exhibits an enhanced therapeutic effect inherited from both membrane-derived tumor homing and step-by-step controlled drug release. Thus, the combination of a biomimetic cell membrane and a cascade-responsive polymeric nanoparticle embodies an effective drug delivery system tailored to the tumor microenvironment.

Dual Functional Peptide-Driven Nanoparticles for Highly Efficient Glioma-Targeting and Drug Codelivery.

Compared with peripheral tumors, glioma is very difficult to treat, not only because it has general features of tumor but also because the therapy has been restricted by the brain-blood barrier (BBB). The two main features of tumor growth are angiogenesis and proliferation of tumor cells. RNA interference (RNAi) can downregulate VEGF overexpression to inhibit tumor neovascularization. Meanwhile, doxorubicin (DOX) has been used for cytotoxic chemotherapy to kill tumor cells. Thus, combining RNAi and chemotherapy has been regarded as a potential strategy for cancer treatment. However, the BBB limits the shVEGF-DOX codelivery system to direct into glioma. Here, a smart drug delivery system modified with a dual functional peptide was established, which could target to transferrin receptor (TfR) overexpressing on both the BBB and glioma. It showed that the dual-targeting delivery system had high tumor targeting efficiency in vitro and in vivo.

Sequentially Triggered Nanoparticles with Tumor Penetration and Intelligent Drug Release for Pancreatic Cancer Therapy

Abstract Pancreatic ductal adenocarcinoma (PDAC) is the most aggressive malignancy with a five year survival rate of <5%. The aberrant expression of extracellular matrix (ECM) in the tumor stroma forms a compact physical barrier, which that leads to insufficient extravasation and penetration of nanosized therapies. To overcome the severe resistance of PDAC to conventional therapies, a sequentially triggered nanoparticle (aptamer/cell‐penetrating peptide‐camptothecin prodrug, i.e., Apt/CPP‐CPTD NPs) with tumor penetration and intelligent drug release profile is designed. An ECM component (tenescin‐C) targeting aptamer (GBI‐10) is modified onto stroma‐permeable cell‐penetrating peptide (CPP) for the in vivo CPP camouflage and PDAC‐homing. In PDAC stroma, tenascin‐C can detach GBI‐10 from CPP and exposed CPP can facilitate further PDAC penetration and tumor cell endocytosis. After being endocytosed into PDAC cells, intracellular high redox potential can further trigger controlled chemodrug release. Apt/CPP‐CPTD NPs show both deep penetration in vitro 3D PDAC spheroids and in vivo tumor sections. The relatively mild in vitro cytotoxicity and excellent in vivo antitumor efficacy proves the improved PDAC targeting drug delivery and decreased systemic toxicity. The design of ECM‐redox sequentially triggered stroma permeable NPs may provide a practical approach for deep penetration of PDAC and enhanced drug delivery efficacy.

Reactive Oxygen Species-Biodegradable Gene Carrier for the Targeting Therapy of Breast Cancer

An ideal gene-carrying vector is supposed to exhibit outstanding gene-condensing capability with positively charged macromolecules to protect the carried gene during in vivo circulation and a rapid dissociation upon microenvironmental stimuli at the aimed sites to release the escorted gene. Currently, it still remains a challenge to develop an ideal gene carrier with efficient transfection ability and low toxicity for clinical applications. Herein, we have innovatively introduced a reactive oxygen species (ROS)-biodegradable boric acid ester linkage in elaborating the design of a gene carrier. In virtue of the featured intracellular characteristics such as the high level of ROS in tumor cells, an ROS-biodegradable electropositive polymer derived from branched polyethylenimine (BPEI) with a low molecular weight (1.2k) through a cross-linking reaction by the boric acid ester bond was developed in this study to achieve condensation and escorting of carried genes. Furthermore, the polymer was modified with substance P (SP) peptide as the targeting ligand through polyethylene glycol. The final fabricated SP-cross-linked BPEI/plasmid DNA nanoparticles exhibit favorable biocompatibility, ROS-cleavability, and fine targeting ability as well as high transfection efficiency compared with parental BPEI1.2k both in vitro and in vivo. SP-cross-linked BPEI/small interfering RNA (pololike kinase 1) polyplex possesses favorable gene-silencing effects in vitro and satisfactory antitumor ability in vivo. Hopefully, this novel cross-linked electropositive polymer may serve well as a safe and efficient gene-delivery vehicle in the clinic.

Substance P-modified human serum albumin nanoparticles loaded with paclitaxel for targeted therapy of glioma

The blood–brain barrier (BBB) and the poor ability of many drugs to cross that barrier greatly limits the efficacy of chemotherapies for glioblastoma multiforme (GBM). The present study exploits albumin as drug delivery vehicle to promote the chemotherapeutic efficacy of paclitaxel (PTX) by improving the stability and targeting efficiency of PTX/albumin nanoparticles (NPs). Here we characterize PTX-loaded human serum albumin (HSA) NPs stabilized with intramolecular disulfide bonds and modified with substance P (SP) peptide as the targeting ligand. The fabricated SP-HSA-PTX NPs exhibited satisfactory drug-loading content (7.89%) and entrapment efficiency (85.7%) with a spherical structure (about 150 nm) and zeta potential of −12.0 mV. The in vitro drug release from SP-HSA-PTX NPs occurred in a redox-responsive manner. Due to the targeting effect of the SP peptide, cellular uptake of SP-HSA-PTX NPs into brain capillary endothelial cells (BCECs) and U87 cells was greatly improved. The low IC50, prolonged survival period and the obvious pro-apoptotic effect shown by TUNEL analysis all demonstrated that the fabricated SP-HSA-PTX NPs showed a satisfactory anti-tumor effect and could serve as a novel strategy for GBM treatment.

Tumor-Targeting Micelles Based on Linear–Dendritic PEG–PTX8 Conjugate for Triple Negative Breast Cancer Therapy

Most small molecular chemotherapeutics have poor water solubility and unexpected pharmacokinetics and toxicity to normal tissues. A series of nano drug delivery systems have been developed to solve the problems, among which a micelle based on linear-dendritic polymer-drug conjugates (LDPDCs) is a promising strategy to deliver hydrophobic chemotherapeutics due to its small size, fine stability in blood circulation, and high drug loading capacity. In this work we synthesized a novel amphiphilic linear-dendritic PEG-PTX8 conjugate which can also encapsulate extra free PTX and self-assemble into uniform ultrasmall micelles with a hydrated diameter of 25.50 ± 0.27 nm. To realize efficient drug delivery to tumor sites, a cyclic tumor homing and penetrating peptide iNGR was linked to the PEG-PTX8 conjugate. The biological evaluation was performed on a human triple negative breast cancer model. PTX accumulation in tumor at 24 h of the TNBC-bearing mice treated with iNGR-PEG-PTX8/PTX micelles was significantly enhanced (P < 0.001, two-way ANOVA) compared to that of Taxol and untargeted MeO-PEG-PTX8/PTX micelles. Furthermore, iNGR-PEG-PTX8/PTX micelles showed an obvious strong antitumor effect, and the median survival time of TNBC bearing mice treated with iNGR-modified micelles was significantly extended compared to Taxol. Therefore, this smart micelle system may be a favorable platform for effective TNBC therapy.

Enhanced bioreduction-responsive diselenide-based dimeric prodrug nanoparticles for triple negative breast cancer therapy

Efficient drug accumulation in tumor is essential for chemotherapy. We developed redox-responsive diselenide-based high-loading prodrug nanoparticles (NPs) for targeted triple negative breast cancer (TNBC) treatment. Method: Redox-responsive diselenide bond (Se-Se) containing dimeric prodrug (PTXD-Se) was synthesized and co-precipitated with TNBC-targeting amphiphilic copolymers to form ultra-stable NPs (uPA-PTXD NPs). The drug loading capacity and redox-responsive drug release behavior were studied. TNBC targeting effect and anti-tumor effect were also evaluated in vitro and in vivo. Results: On-demand designed paclitaxel dimeric prodrug could co-precipitate with amphiphilic copolymers to form ultra-stable uPA-PTXD NPs with high drug loading capacity. Diselenide bond (Se-Se) in uPA-PTXD NPs could be selectively cleaved by abnormally high reduced potential in tumor microenvironment, releasing prototype drug, thus contributing to improved anti-cancer efficacy. Endowed with TNBC-targeting ligand uPA peptide, uPA-PTXD NPs exhibited reduced systemic toxicity and enhanced drug accumulation in TNBC lesions, thus showed significant anti-tumor efficacy both in vitro and in vivo. Conclusion: The comprehensive advantage of high drug loading, redox-controlled drug release and targeted tumor accumulation suggests uPA-PTXD NPs as a highly promising strategy for effective TNBC treatment.

Platinum-Based Nanovectors Engineered with Immuno-Modulating Adjuvant for Inhibiting Tumor growth and Promoting Immunity

Although there is ample evidence that the chemotherapeutic drugs trigger an immune response, the efficient tumor rejection or regression is not guaranteed probably due to the massive immunosuppression within the tumor microenvironment. Thus, a rational delivery platform that overcomes immunosuppression is needed to maximally achieve both cytotoxic and immune-modulatory functions of chemotherapeutics. Accumulating evidence suggests that platinum-based drugs might be suitable for this application. Methods: The dendrigraft polylysine (DGL) with its uniform size and multifunctional groups was employed as the polymeric core and conjugated with platinum-based compounds as therapeutics and WKYMVm peptide (Wpep) as a targeting ligand to construct the novel delivery platform Wpep-DGL/Pt. A series of in vitro and in vivo analyses, including physical and chemical characterizations, targeting property, biosafety, and antitumor efficacy of Wpep-DGL/Pt were systematically carried out. Results: Wpep-DGL/Pt showed potent antitumor efficacy in MDA-MB-231 cells tumor-bearing nude mice with a deficient immune system, demonstrating targeted delivery of chemotherapeutics and the resultant cytotoxicity. Furthermore, in immunocompetent mice bearing 4T1 cells tumors, Wpep-DGL/Pt activated immune cells and induced cell death proving their dual function of chemotherapeutic and immunomodulatory efficacy. Conclusion: This work represents a novel approach for cancer immunotherapy by integrating nanotechnology and platinum-based therapeutics which not only efficiently exerts the chemotherapeutic cytotoxic effect on tumor cell but also restores immune response of immunological cells within the tumor microenvironment.