Most of antieancer agents can not be used for treatment of brain glioma due to the existence of the blood brain barrier （BBB）. The over-expression of glucose transporters （GLUTs） on the BBB and brain glioma cells enables the possibility that the GLUTs ligand modified drug carrier transports across the BBB, and targets to the brain glioma cells. The objectives of the present study were to synthesize a new glucose conjugate material, TPGS1000-Glu, develop a kind of TPGSI00o-Glu modified epirubicin liposomes, and evaluate their efficacy. The studies were performed on the BBB co-culture model and brain glioma cells in vitro. TPGS 1000-Glu was synthesized by conjugating TPGSlo00_COOH with 4-aminophenyl-[3-D-glucopyranoside （Glu）, and confirmed by MALDI-TOF-MS spectrum. TPGS^0oo-GIu modified epirubicin liposomes were prepared with a high drug encapsulation efficiency （〉97%）, a nanosize （approximately 90 nm）, and a minimal drug leakage in fetal bovine serum （FBS）-containing buffer system. The BBB co-culture model was established, and after applying TPGSl0oo-Glu modified epirubicin liposomes to the model, transport of liposomal drug across the BBB was evidenced. Besides, TPGS1000-Glu modified epirubicin liposomes showed the strongest cellular drug uptake and anti-glioma efficacy after transport across the BBB in vitro. The synthesized TPGS1000-Glu material could offer a new targeting ligand for the BBB, while the developed TPGS1000-Glu modified epirubicin liposomes might provide a potential anticancer formulation for treatment of brain glioma.
Considering the results of our previous research that conjugated linoleic acid mixture-paclitaxel （CLA-mixture-PTX） possesses anti-tumor activity against melanoma and brain glioma, the purpose of this study was to investigate the potential anti-tumor efficacy of cis-9, trans- 1 1-conjugated linoleic acid-paclitaxel （c9, tl 1-CLA-PTX） and trans- 1 O, cis- 12-conjugated linoleic acid-paclitaxel （tl0, c12-CLA-PTX） on MCF-7 breast cancer cell line in vitro and in vivo. The in vitro cytotoxicity, apoptosis induction effect and cell cycle arresting effect of c9, t1 1-CLA-PTX and t10, c12-CLA-PTX were investigated. The in vitro cellular uptake of c9, tl 1-CLA-PTX and tl0, cl2-CLA-PTX in MCF-7 cells were also analyzed. Besides, the anti-tumor activity of c9, tl 1-CLA-PTX and tl0, cl2-CLA-PTX was evaluated in MCF-7 tumor bearing nude mice in vivo. The in vitro cytotoxicity results showed that the value of ICs0 of the tl 0, c l2-CLA-PTX is （0.17±0.02） μM, compared with that of （1.08±0.15） μM in CLA-mixture-PTX and （6.50±1.20） μM in c9, tl 1-CLA-PTX treatment group （P〈0.01）. Both tl0, cl2-CLA-PTX and c9, t l 1-CLA-PTX increased the percentage of total apoptotic cells compared with that of control （P〈0.01）. And the rank of apoptosis induction efficacy was t 10, c 12-CLA-PTX〉CLA-mixture-PTX〉c9, t 11-CLA-PTX （P〈0.01）. Compared with untreated cells, the tl0, c12-CLA-PTX and c9, tl 1-CLA-PTX arrested cell cycle progression at the S and G2-M phase. The amount of cellular uptake of t 10, c 12-CLA-PTX was significantly higher than that of CLA-mixture-PTX （P〈0.01）, which was significantly higher than that of c9, t1 1-CLA-PTX （P〈0.01）. The rank of in vivo anti-tumor activity was tl0, c12-CLA-PTX〉CLA-mixture-PTX〉 c9, t1 1-CLA-PTX （P〈0.01）. In conclusion, our study demonstrated that both tl0, cl2-CLA-PTX and c9, tl 1-CLA-PTX has significant anti-tumor activity in MCF-7 cell line. And while c9, tl 1-CLA-PTX showed weaker inhibitory effect than CLA-mixture-PTX, str
Somatostatin receptors （SSTRs） were widely expressed in many tumor cells. As a somatostatin analogue, vapreotide （VAP） can be exploited as a modifier for targeting tumor therapy based on its high affinity to SSTR. In this study, we conjugated α-NH2 of exocyclic n-phenylalanine （D-Phe） of vapreotide to N-hydroxysuccinimidyl-PEG2000-DSPE （NHS-PEG-DSPE）, and the resulted DSPE-PEG-VAP was used as a targeting component to construct the targeted micelles for delivering paclitaxel （VAP-M-PTX） through a thin-film hydration method. Similar particle size, zeta potential, drug encapsulation efficiencies, drug release behaviors and hemolysis effects were observed between the targeted micelles （VAP-M-PTX） and the non-targeted micelles （M-PTX）. In MCF-7 cells, significantly higher intracellular fluorescence intensity （1.5-fold） was determined by flow cytometry after incubation of coumarin-6 loaded targeted micelles （VAP-M-Cou） for 3 h compared with non-targeted mieelles （M-Cou）, and similar finding was observed confocal microscopy. Furthermore, in comparison with non-targeted formulations, higher antitumor efficacy and higher drug accumulation were found in MCF-7 tumors in nude mice after intravenous injection of the targeted micelles. In conclusion, we believed that the vapreotide-modified nanomicelles could be a promising targeted nanocarrier for delivering anticancer drugs to the tumors with overexpression of somatostatin receptors.
The present study aimed to investigate the targeting effect of H7K（R2）2-modified pH -sensitive liposomes on U87-MG cells. Using coumarin-6 as a fluorescence probe, we prepared H7K（R2）2-modified p H-sensitive liposomes（designated as coumarin-6-PSL-H7K（R2）2）. The flow cytometry assay was used to evaluate the effect of H7K（R2）2 proportions on the cellular uptake and endocytosis pathways of coumarin--6--PSL--H7K（R2）2 on U87-MG cells. The circular dichroism（CD） spectroscopy assay was used to investigate the secondary structures of H7K（R2）2 peptide at pH 7.4 and H 6.8, respectively. Our results indicated that the 2.5% proportion of H7K（R2）2 in the coumarin-6--PSL-H7K（R2）2 was superior to those of 1% and 3.5% of H7K（R2）2. The uptake of coumarin--6-PSL--H7K（R2）2 on U87--MG cells was not inhibited by filipin, M-β--CD or chlorpromazine. The secondary structure of H7K（R2）2 at pH 6.8 was mostly presented as β--turn. In conclusion, we suggested that the appropriate proportion of H7K（R2）2 in the H7K（R2）2--modified pH--sensitive liposomes could be set at 2.5%. The cellular uptake pathway for H7K（R2）2-modified pH--sensitive liposomes was via the cell penetrating capacity of H7K（R2）2 which responded to acidic condition. The secondary structure of H7K（R2）2 at pH 6.8, which was presented as the shape of hairpin, might be mainly responsible for its targeting and cell penetrating effect.
Surface modification may have important influences on the penetration behavior of nanoscale drug delivery system. In the present study, we mainly focused on whether cell targeting or cell penetration could affect penetration abilities of nanostructured lipid carriers（NLC）. Real--time penetration of folate--or cell penetrating peptide（CPP）-modified NLC was evaluated using a multicellular tumor spheroid（MTS） established by stacking culture method as an in vitro testing platform. The results suggested that CPP modification had a better penetration behavior both on penetration depth and intensity compared with folate-modified NLC at the early stage of penetration process.
Nanoparticles have been widely applied in diagnosis and therapy due to the high loading of insoluble drug, increased target accumulation and interaction with biological tissues. Recently, severe side effects of nanoparticles have been reported, but the underlying mechanism remains largely unknown. In our study, we aim to understand the safety of paclitaxel （PTX） loaded bovine albumin nanoparticles （BNPs） and active targeted PTX loaded BNPs to normal vital organ or tissue in vivo. The anti-human epidermal growth factor receptor 2 （HER2/neu） peptide mimetic （AHNP） was covalent bound to surface of BNPs （AHNP-BNPs） to exert selected delivery to HER2＋ cells. In HER2＋ tumor xenographs, saline （control）, PTX traditional formula （medium of Cremophor EL-ethanol）, BNPs, and AHNP-BNPs were administrated to evaluate the toxicity. There is no severe neutropenia or anemia with treatment of BNPs and AHNP-BNPs compared with traditional PTX injection. We also evaluated their damage on normal organs, including liver, kidney, spleen, lung and heart to fully estimate the safety of AHNP-BNPs and BNPs delivery systems. We observed similar toxicity in liver and lung in mice treated with BNPs or PTX injection, but decreased liver damage in mice treated with AHNP-BNPs. Further studies are rcouired to confirm our conclusion.
