http://hdl.handle.net/10397/178 Search the Channel search http://repository.lib.polyu.edu.hk/jspui/simple-search http://hdl.handle.net/10397/5645 Title: Polyethylenimine-based amphiphilic core-shell nanoparticles: study of gene delivery and intracellular trafficking<br/><br/>Authors: Siu, Yuen Shan; Li, Lijun; Leung, Man-fai; Lee, K. L. Daniel; Li, Pei Pauline<br/><br/>Abstract: Amphiphilic core-shell nanoparticle, which is composed of a hydrophobic core and a branched polyethylenimine (PEI) shell, has been designed and synthesized as a novel gene delivery nanocarrier. In our previous study, we demonstrated that the core-shell nanoparticle was not only able to efficiently complex with plasmid DNA (pDNA) and protect it against enzymatic degradation, but also three times less cytotoxic, and threefold more efficient in gene transfection than branched 25 kDa PEI. This paper reports our further studies in the following three aspects: (1) the ability of the PEI-based nanoparticles to deliver gene in various mammalian cell lines; (2) intracellular distributions of the nanoparticles and their pDNA complexes in HeLa cells; and (3) incorporation of nuclear targeting agent into the nanoparticle/pDNA complexes to enhance the nuclear targeting ability. The PEI-based nanoparticles were able to transfect both human and non-human cell lines and their transfection efficiencies were cell-dependent. Within our four tested cell lines (MCF-7, BEL 7404, C6 and CHO-K1), gene transfer using PEI-based core-shell nanoparticles displayed gene expression levels comparable to, or even better than, the commercial Lipofectamine™ 2000. Confocal laser scanning microscopy showed that the nanoparticles and their pDNA complexes were effectively internalized into the HeLa cells. The in vitro time series experiments illustrated that both the nanoparticle/pDNA complexes and PEI-based nanoparticles were distributed in the cytoplasmic region after transfection for 10 and 60 min, respectively. Nuclear localization was also observed in both samples after transfection for 20 and 60 min, respectively. Incorporation of the high mobility group box 1 (HMGB1) protein for nuclear targeting has also been demonstrated with a simple approach: electrostatic complexation between the PEI-based nanoparticles and HMGB1. In the in vitro transfection study in MCF-7 cells, the expression level of the firefly luciferase gene encoded by the pDNA increased remarkably by up to eightfold when the HMGB1 protein was incorporated into the nanoparticle/pDNA complexes. Our results demonstrate that the PEI-based core-shell nanoparticles are promising nanocarriers for gene delivery.<br/><br/>Description: DOI: 10.1007/s13758-011-0016-4 http://hdl.handle.net/10397/5618 Title: Conditional inactivation of Pten with EGFR overexpression in Schwann cells models sporadic MPNST<br/><br/>Authors: Keng, Wee-Keong Vincent; Watson, Adrienne L.; Rahrmann, Eric P.; Li, Hua; Tschida, Barbara R.; Moriarity, Branden S.; Choi, Kwangmin; Rizvi, Tilat A.; Collins, Margaret H.; Wallace, Margaret R.; Ratner, Nancy; Largaespada, David A.<br/><br/>Abstract: The genetic mechanisms involved in the transformation from a benign neurofibroma to a malignant sarcoma in patients with neurofibromatosis-type-1- (NF1-)associated or sporadic malignant peripheral nerve sheath tumors (MPNSTs) remain unclear. It is hypothesized that many genetic changes are involved in transformation. Recently, it has been shown that both phosphatase and tensin homolog (PTEN) and epidermal growth factor receptor (EGFR) play important roles in the initiation of peripheral nerve sheath tumors (PNSTs). In human MPNSTs, PTEN expression is often reduced, while EGFR expression is often induced. We tested if these two genes cooperate in the evolution of PNSTs. Transgenic mice were generated carrying conditional floxed alleles of Pten, and EGFR was expressed under the control of the 2′,3′-cyclic nucleotide 3′phosphodiesterase (Cnp) promoter and a desert hedgehog (Dhh) regulatory element driving Cre recombinase transgenic mice (Dhh-Cre). Complete loss of Pten and EGFR overexpression in Schwann cells led to the development of high-grade PNSTs. In vitro experiments using immortalized human Schwann cells demonstrated that loss of PTEN and overexpression of EGFR cooperate to increase cellular proliferation and anchorage-independent colony formation. This mouse model can rapidly recapitulate PNST onset and progression to high-grade PNSTs, as seen in sporadic MPNST patients.<br/><br/>Description: DOI: 10.1155/2012/620834 http://hdl.handle.net/10397/5579 Title: Panax ginsengRhodiola rosea and schisandra chinensis<br/><br/>Authors: Chan, Shun-wan<br/><br/>Abstract: Panax ginseng (Ginseng), Rhodiola rosea (Hong Jing Tian) and Schisandra chinensis (Wu Wei Zi) are well-known herbs in traditional Chinese medicine (TCM). Recently, there have been a number of studies on these three herbs. This review discusses their active components and major pharmacological effects. For P. ginseng, it has been shown to have an anti-inflammatory activity, affects pulmonary function and erectile dysfunction, improves cognition in patients with Alzheimer's disease and promotes sexual arousal in menopausal women as well as prevents cancer. For R. rosea, its effectiveness in alleviating depression and reducing fatigue is summarized in this review. Additionally, anti-cancer and other clinical effects of S. chinensis are also discussed. These three herbs are considered as adaptogens as they bear multiple functions and their effects were found to be very different in patients depending on the circumstances (age, gender, environment, diet, season, etc.). Thus, in most cases, the art of the TCM practitioner is to prescribe these herbs after a complete evaluation of overall heath status of the patients.<br/><br/>Description: DOI: 10.3109/09637486.2011.627840 http://hdl.handle.net/10397/5295 Title: Discriminating Astragali Radix from its adulterants using HPLC coupled with chemometric clustering techniques<br/><br/>Authors: Dong, Wei-Wei; Au, Dawn; Cao, Xin-Wei; Li, Xiao-Bo; Yang, Dajian<br/><br/>Abstract: A simple high-performance liquid chromatography (HPLC) method coupled with principal component analysis (PCA) and hierarchical cluster analysis (HCA) was developed for distinguishing Astragali Radix from its adulterants. Five species, including A. membranaceus var. mongolicus, A. membranaceus, H. polybotrys, A. chrysopterus and A. ernestii, were analyzed by this method. At the same time, four major bioactive isoflavonoids, namely calycosin-7-O-D-glucopyranoside, ononin, calycosin and formononetin, were simultaneously determined in Astragali Radix. This method was proven to have good precision, repeatability, stability and recovery. It was successfully applied to distinguish Astragali Radix from its adulterants species and can be used for the quality control of Astragali Radix.