Huaiyu Liu

Co-delivery of doxorubicin and paclitaxel by PEG-polypeptide nanovehicle for the treatment of non-small cell lung cancer

Despite progress, combination therapy of different functional drugs to increase the efficiency of anticancer treatment still remains challenges. An amphiphilic methoxy poly(ethylene glycol)-b-poly(l-glutamic acid)-b-poly(l-lysine) triblock copolymer decorated with deoxycholate (mPEsG-b-PLG-b-PLL/DOCA) was synthesized and developed as a nanovehicle for the co-delivery of anticancer drugs: doxorubicin (DOX) and paclitaxel (PTX). The amphiphilic copolymer spontaneously self-assembled into micellar-type nanoparticles in aqueous solutions and the blank nanoparticles possessed excellent stability. Three different domains of the copolymer performed distinct functions: PEG outer corona provided prolonged circulation, middle biodegradable and hydrophilic PLG shell was designed for DOX loading through electrostatic interactions, and hydrophobic deoxycholate modified PLL served as the container for PTX. In vitro cytotoxicity assays against A549 human lung adenocarcinoma cell line demonstrated that the DOX + PTX co-delivered nanoparticles (Co-NPs) exhibited synergistic effect in inducing cancer cell apoptosis. Ex vivo DOX fluorescence imaging revealed that Co-NPs had highly efficient targeting and accumulation at the implanted site of A549 xenograft tumor in vivo. Co-NPs exhibited significantly higher antitumor efficiency in reducing tumor size compared to free drug combination or single drug-loaded nanoparticles, while no obvious side effects were observed during the treatment, indicating this co-delivery system with different functional antitumor drugs provides the clinical potential in cancer therapy.

Doxorubicin-loaded amphiphilic polypeptide-based nanoparticles as an efficient drug delivery system for cancer therapy.

An amphiphilic anionic copolymer, methoxy poly(ethylene glycol)-b-poly(l-glutamic acid-co-l-phenylalanine) (mPEG-b-P(Glu-co-Phe)), with three functionalized domains, was synthesized and used as a nanovehicle for cationic anticancer drug doxorubicin hydrochloride (DOX·HCl) delivery via electrostatic interactions for cancer treatment. The three domains displayed distinct functions: PEG block chain for prolonged circulation; poly(phenylalanine) domain for stabilizing the nanoparticle construct through hydrophobic/aromatic interactions; and the poly(glutamic acid) domain for providing electrostatic interactions with the cationic drug to be loaded. The copolymer could self-assemble into micellar-type nanoparticles, and DOX was successfully loaded into the interior of nanoparticles by simple mixing of DOX·HCl and the copolymer in the aqueous phase. DOX-loaded mPEG-b-P(Glu-co-Phe) nanoparticles (DOX-NP) had a superior drug-loading content (DLC) (21.7%), a high loading efficiency (almost 98%) and a pH-triggered release of DOX. The size of DOX-NP was ∼140 nm, as determined by dynamic light scattering measurements and transmission electron microscopy. In vitro assays showed that DOX-NP exhibited higher cell proliferation inhibition and higher cell uptake in A549 cell lines compared with free DOX·HCl. Maximum tolerated dose (MTD) studies showed that DOX-NP demonstrated an excellent safety profile with a significantly higher MTD (15 mg DOX kg(-1)) than that of free DOX·HCl (5 mg DOX kg(-1)). The in vivo studies on the subcutaneous non-small cell lung cancer (A549) xenograft nude mice model confirmed that DOX-NP showed significant antitumor activity and reduced side effects, and then enhanced tumor accumulation as a result of the prolonged circulation in blood and the enhanced permeation and retention effect, compared with free DOX, indicating its great potential for cancer therapy.

Methoxypoly(ethylene glycol)-block-Poly(L-glutamic acid)-Loaded Cisplatin and a Combination With iRGD for the Treatment of Non-Small-Cell Lung Cancers

CDDP is loaded into methoxypoly(ethylene glycol)-block-poly(L-glutamic acid) (mPEG-b-PLG), and a combination with iRGD is applied for NSCLC chemotherapy. The CDDP-loaded micelles show sustained cisplatin release in PBS, dose- and time-dependent inhibition to HeLa and A549 cell proliferation, and no apparent hemolysis activities. In in vivo studies using subcutaneous NSCLC xenograft models (A549), both free CDDP and CDDP-loaded micelles show an evident anti-tumor effect. However, the toxicity of CDDP is significantly reduced in the cases of CDDP-loaded micelles and co-administration with iRGD, and the survival time is prolonged by over 30%. Therefore, mPEG-b-PLG-loaded cisplatin and the combination with iRGD provides a promising new therapy for NSCLC.

Polypeptide-based combination of paclitaxel and cisplatin for enhanced chemotherapy efficacy and reduced side-effects.

A novel methoxy poly(ethylene glycol)-b-poly(l-glutamic acid)-b-poly(l-phenylalanine) (mPEG-b-P(Glu)-b-P(Phe)) triblock copolymer was prepared and explored as a micelle carrier for the co-delivery of paclitaxel (PTX) and cisplatin (cis-diamminedichlo-platinum, CDDP). PTX and CDDP were loaded inside the hydrophobic P(Phe) inner core and chelated to the middle P(Glu) shell, respectively, while mPEG provided the outer corona for prolonged circulation. An in vitro release profile of the PTX+CDDP-loaded micelles showed that the CDDP chelation cross-link prevented an initial burst release of PTX. The PTX+CDDP-loaded micelles exhibited a high synergism effect in the inhibition of A549 human lung cancer cell line proliferation over 72 h incubation. For the in vivo treatment of xenograft human lung tumor, the PTX+CDDP-loaded micelles displayed an obvious tumor inhibiting effect with a 83.1% tumor suppression rate (TSR%), which was significantly higher than that of a free drug combination or micelles with a single drug. In addition, more importantly, the enhanced anti-tumor efficacy of the PTX+CDDP-loaded micelles came with reduced side-effects. No obvious body weight loss occurred during the treatment of A549 tumor-bearing mice with the PTX+CDDP-loaded micelles. Thus, the polypeptide-based combination of PTX and CDDP may provide useful guidance for effective and safe cancer chemotherapy.

Polypeptide/Doxorubicin Hydrochloride Polymersomes Prepared Through Organic Solvent-free Technique as a Smart Drug Delivery Platform

Rapid and efficient side-chain functionalization of polypeptide with neighboring carboxylgroups is achieved via the combination of ring-opening polymerization and subsequent thiol-yne click chemistry. The spontaneous formation of polymersomes with uniform size is found to occur in aqueous medium via electrostatic interaction between the anionic polypeptide and cationic doxorubicin hydrochloride (DOX·HCl). The polymersomes are taken up by A549 cells via endocytosis, with a slightly lower cytotoxicity compared with free DOX ·HCl. Moreover, the drug-loaded polymersomes exhibit the enhanced therapeutic efficacy, increase apoptosis in tumor tissues, and reduce systemic toxicity in nude mice bearing A549 lung cancer xenograft, in comparison with free DOX ·HCl.

Poly(ester amide) blend microspheres for oral insulin delivery

This study developed a novel oral insulin formulation centered on microspheres consisting of a blend of biodegradable poly(ester amide) (PEA). In the formulation, L-lysine-/L-leucine-based PEA with pendant COOH groups (PEA-COOH) was used as a pH-responsive material for the protection of insulin from the harsh environmental conditions of the stomach. Arginine-based PEA (Arg-PEA) was introduced to improve the intestinal absorption of the drug. The influence of both the hydrophobicity of PEA-COOH and the content of Arg-PEA was investigated in detail on microsphere surface morphology, drug loading, and the in vitro release profile of insulin. The PEA-COOH/Arg-PEA blend microspheres protected the loaded insulin in simulated gastric fluid and released insulin in a fast and sustained manner in simulated intestinal fluid. The in vivo test demonstrated that the oral administration of insulin-loaded PEA blend microspheres could effectively suppress the blood glucose level in diabetic rats for 10h, and the oral bioavailability was improved to 5.89+1.84% in healthy rats. These results indicate that the PEA blend microspheres are promising vehicles for the oral delivery of insulin.

Preparation of pingyangmycin PLGA microspheres and related in vitro/in vivo studies

Using a multiple emulsion solvent evaporation method, pingyangmycin was entrapped in poly(lactic-co-glycolic acid) (PLGA) to prepare a long-acting pingyangmycin PLGA microsphere formulation that can be sustainably released with high entrapment efficiency. Meanwhile, the effects of stirring speed during the multiple emulsion solvent evaporation process were also taken into consideration. Investigation of the in vitro release properties showed that the microsphere formulations could sustainably release the drug over nearly 28 d, and, moreover, it could stably control pingyangmycin release over nearly 24 d when intramuscularly injected into dogs. No serious toxic effect was observed in an acute toxicity test in mice. A subcutaneous xenotransplant model of hepatoma H(22) in mice was established for pharmacodynamic studies and the results showed that the process of preparing pingyangmycin PLGA microsphere formulations was feasible and that intramuscular injection of this microsphere formulation resulted in anti-tumor activity in vivo.

Inhibiting Solid Tumor Growth In Vivo by Non-Tumor-Penetrating Nanomedicine

Nanomedicine (NM) cannot penetrate deeply into solid tumors, which is partly attributed to the heterogeneous microenvironment and high interstitial fluid pressure of solid tumors. To improve NM efficacy, there has been tremendous effort developing tumor-penetrating NMs by miniaturizing NM sizes or controlling NM surface properties. But progress along the direction of developing tumor penetrating nanoparticle has been slow and improvement of the overall antitumor efficacy has been limited. Herein, a novel strategy of inhibiting solid tumor with high efficiency by dual-functional, nontumor-penetrating NM is demonstrated. The intended NM contains 5,6-dimethylxanthenone-4-acetic acid (DMXAA), a vascular-disrupting agent, and doxorubicin (DOX), a cytotoxic drug. Upon arriving at the target tumor site, sustained release of DMXAA from NMs results in disruption of tumor vessel functions, greatly inhibiting the interior tumor cells by cutting off nutritional supply. Meanwhile, the released DOX kills the residual cells at the tumor exterior regions. The in vivo studies demonstrate that this dual-functional, nontumor penetrating NM exhibits superior anticancer activity, revealing an alternative strategy of effective tumor growth inhibition.

Preparation of Bleomycin A2–PLGA Microspheres and Related In Vitro and In Vivo Studies

The goals of these studies were to prepare bleomycin (BLM) A(2)-poly(lactic-co-glycolic acid) (PLGA) microspheres and to investigate their in vitro release, pharmacokinetics, pharmacodynamics, and toxicology of this product. Long-acting BLM A(2)-PLGA microspheres were prepared using multiple emulsion solvent evaporation, and the related characteristics of the microspheres were investigated. The prepared microspheres were administered to dogs via intramuscular injection. The plasma concentration of BLM A(2) in dogs was detected using liquid chromatography-mass spectrometry. The pharmacodynamics of BLM A(2)-PLGA microspheres were investigated in a golden hamster model. The acute and chronic toxicities were investigated in a rat model. The inductive effects of BLM microspheres versus a conventional formulation on pulmonary injuries were compared in a mouse model. BLM A(2)-PLGA microspheres were released stably over 20 days and exhibited a significant inhibition of oral squamous carcinoma. The acute toxicity study suggested that doses up to 128 mg/kg were acceptable, and the chronic toxicity study showed no significant chronic toxicity. The study in mice showed less pulmonary toxicity with BLM microsphere formulation compared with the conventional formulation. As a novel microsphere drug formulation, BLM A(2)-PLGA microspheres showed a significant slow-release effect. These data may provide a new clinical medication option for patients with oral cancer.