Paclitaxel(PTX) is one of the most effective anticancer drugs for the treatment of various solid tumors, but its clinical use is limited by its poor solubility, low bioavailability, and severe systemic toxicity. Encapsulation of PTX in polymeric nanoparticles is used to overcome these problems but these micelles still need improvements in stability, pharmacokinetics, therapeutic efficacy, and safety profiles. In this study, we demonstrate a facile fabrication of a stable PTX-binding micelle made from poly(ethylene glycol)-block-dendritic polylysine, whose primary amines were reacted with phenethyl isothiocyanate(PEITC), a hydrophobic anticancer agent under clinical study. The amphiphilic conjugate(PEG-Gx-PEITC; Gx, the generation of the polylysine dendron) formed well-defined micelles whose core was composed of phenyl groups and thiourea groups binding PTX via π-π stacking and hydrogen bonding. Compared with the PTX-loaded poly(ethylene glycol)-block-poly(D,L-lactide)(PEGPDLLA/PTX) micelles in clinical use, PTX-loaded PEG-Gx-PEITC third-generation(PEG-G3-PEITC/PTX) micelles showed slowed blood clearance, enhanced tumor accumulation, and thus much improved in vivo therapeutic efficacy in both subcutaneous and orthotopic human breast cancer xenografts. Therefore, PEG-G3-PEITC is a promising drug delivery system for PTX in the treatment of breast cancer.
Brain delivery of macromolecular therapeutics (e.g., proteins) remains an unsolved problem because of the formidable blood brain bather (BBB). Although a direct pathway of nose-to-brain transfer provides an answer to circumventing the BBB and has already been intensively investigated for brain delivery of small drugs, new challenges arise for intranasal delivery of proteins because of their larger size and hydrophilicity. h order to overcome the bathers and take advantage of available pathways (e.g., epithelial tight junctions, uptake by olfactory neurons, transport into brain tissues, and intra-brain diffusion), a low molecular weight protamine (LMWP) cell-penetrating peptide was utilized to facilitate nose-to-brain transport. Cell-penetrating peptides (CPP) have been widely used to mediate macromolecular delivery through many kinds of biobarriers. Our results show that conjugates of LMWP proteinsare able to effectively penetrate into the brain after intranasal administration. The CPP-based intranasal method highlights a promising solution for protein therapy of brain diseases. (C) 2016 Chinese Pharmaceutical Association and Institute of Materia Medica, Chinese Academy of Medical Sciences. Production and hosting by Elsevier B.V.
Local hypoxia in solid tumors often results in resistance to radiotherapy （RT）, in which oxygen is an essential element for enhancing DNA damage caused by ionizing radiation. Herein, we developed gold@manganese dioxide （Au@MnO2） core-shell nanoparticles with a polyethylene glycol （PEG） coating as a novel radiosensitizing agent to improve RT efficacy during cancer treatment. In this Au@MnO2 nanostructure, while the gold core is a well-known RT sensitizer that interacts with X-rays to produce charged particles for improved cancer killing under RT, the MnO2 shell may trigger the decomposition of endogenous H2O2 in the tumor microenvironment to generate oxygen and overcome hypoxiaassociated RT resistance. As demonstrated by both in vitro and in vivo experiments, Au@MnO2-PEG nanoparticles acted as effective radiosensitizers to remarkably enhance cancer treatment efficacy during RT. Moreover, no obvious side effects of Au@MnO2-PEG were observed in mice. Therefore, our work presents a new type of radiosensitizer with potential for enhanced RT treatment of hypoxic tumors.
Xuan YiLei ChenXiaoyan ZhongRoulin GaoYitao QianFan WuGuosheng SongZhifang ChaiZhuang LiuKai Yang
The stability and size of polymeric nanoparticles are two of the most important parameters determining their pharmacokinetics and tumor/drug accumulation efficiency in cancer-drug delivery. Herein, we report a facile one-pot synthesis of crosslinked nanoparticles(CNPs) with tunable sizes and polyethylene glycol(PEG) shells via click reactions. Simply by adjusting the contents of the macromonomer(PEG monoacrylate) in its reaction with ethylene diacrylate and a crosslinker containing hexa-thiols groups, the sizes of the resulting PEGylated crosslinked nanoparticles could be easily tuned from 10 to 90 nm. These nanoparticle cores could encapsulate hydrophobic drugs such as doxorubicin(DOX), and the unreacted thiol and acrylate groups could be used for drug conjugation or labeling. Thus, the nanoparticles provide a multifunctional platform for drug delivery. In vivo studies showed that the larger nanoparticles(about 83.7 nm) had a much longer blood-circulation time and better tumor-targeting efficiency. One of our most important findings was that the drug encapsulated in the crosslinked nanoparticles, even though little was released at pH 7.4 under in vitro conditions, had much faster blood clearance than the nanoparticles' carrier, suggesting that drug release in the bloodstream was significant.
CAO MingLIU XiangRuiTANG JianBinSUI MeiHuaSHEN YouQing
It remains a great challenge to explore the facile way to fabricate multi-component nanoparticles in theranostic nanomedicine. Herein, an albumin nanoreactor templated synthesis of theranostic Gd203/CuS hybrid nanodots （NDs） has been developed for multimodal imaging guided photothermal tumor ablation. Gd2O3/CuS NDs are found to possess particle size of 4.4 ± 1.1nm, enhanced longitudinal relaxivity, effective photothermal conversion of 45.5%, as well as remarkable near-infrared fluorescence （NIRF） from Cy7.5-conjugated on albumin corona. The Gd203/CuS NDs further exhibited good photostability, en- hanced cellular uptake, and preferable tumor accumulation. Thus, the Gd203/CuS NDs generate remarkable NIRF imag- ing and Tl-weighted magnetic resonance （MR） imaging, and simultaneously result in effective photothermal tumor ab- lation upon irradiation. The albumin nanoreactor provides a facile and general strategy to synthesize multifunctional nanoparticles for cancer theranostics.
