递送siRNA的EGFR靶向免疫脂质体的制备及其体内外活性研究
详细信息    本馆镜像全文|  推荐本文 |  |   获取CNKI官网全文
摘要
基因治疗是目前治疗遗传性疾病或后天获得性疾病比较理想的治疗手段,尤其是恶性肿瘤的治疗。RNAi(RNA interfering, RNA干扰)作为一种高效的序列特异性基因沉默技术在恶性肿瘤基因治疗领域发展掀起了一股研究热潮,其中,siRNA(small interfering RNA,小干扰RNA)是RNAi路径中的效应分子,它是一种21~23 bp的短片段双链RNA,能够特异性降解同源序列的mRNA,抑制特异肿瘤相关基因的表达,从而达到抑制肿瘤生长、侵袭和转移的目的。然而,如果没有载体的帮助,siRNA无法进入肿瘤细胞内,载体是制约siRNA基因治疗的首要问题,所以,siRNA的递送载体研究是目前肿瘤基因治疗研究的热点问题。阳离子脂质体是目前应用较为广泛的递送siRNA的一种非病毒载体,它具有无毒、可自然降解、无免疫原性、可以大量合成并放大生产等优点,近年来备受研究者的重视。
     本课题组前期一直致力于递送siRNA的阳离子脂质体的制备和活性研究,前期研究发现,通过对阳离子脂质体进行PEG(聚乙二醇)化、HER2抗体修饰以及冷冻干燥等处理后制备得到一种PEG化免疫冻干脂质体(Lyophilized PEGylated Immunoliposomes, LPIL),这种脂质体在PEG含量为2.5 mol%时,能有效的将siRNA特异性递送至高表达HER2乳腺癌细胞内并沉默相关基因的表达。PEG能显著提高脂质体在血浆中的稳定性,延长药物体内半衰期,当PEG含量大于8 mol%时,粒径为100 nm左右的脂质体表面呈刷状,这种刷状构象能完全覆盖脂质体表面,为脂质体免于网状内皮系统的吞噬提供更全面的保护。然而LPIL的PEG含量较低,体内应用受到限制。并且,LPIL无法引入较高含量的PEG,因为较高含量的PEG会破坏LPIL的物理稳定性,而且会大大降低siRNA的包封率。所以我们亟待发展一种高PEG含量、高siRNA包封率以及靶向性较好的阳离子脂质体。
     LPD(liposome-polycation-DNA,脂质体-多聚阳离子-DNA复合物)是一种新型递送siRNA的阳离子脂质体,它的结构是PEG(聚乙二醇)化的包裹鱼精蛋白、siRNA/DNA复合物的阳离子脂质体,与传统阳离子脂质体不同的是,DNA在鱼精蛋白的作用下将siRNA压缩,三者形成一个紧密的带负电的核,与阳离子脂质体混合后通过自组装过程形成稳定的LPD,尤为重要的是,LPD采用后插入PEG的方法在其表面修饰了高含量的PEG,不但保证了siRNA的高包封率,而且有效地增加了脂质体的稳定性,在体内被证明能有效地递送siRNA至肿瘤细胞中。然而,抗体修饰的LPD尚无人系统探讨过其各种纳米表征和体内外活性。本研究正是在前期PEG化免疫阳离子脂质体和LPD的基础之上,通过一系列的处方筛选,首次优化出一种高PEG含量的EGFR靶向免疫脂质体TLPD-FCC,并对其各种纳米表征及其体内外活性进行了较为深入的研究和探讨。
     首先,我们将DOTAP/Chol阳离子脂质体与鱼精蛋白、小牛胸腺DNA、siRNA混合得到Naked LPD(非PEG化脂质体),然后通过PEG化和引入抗体(Anti-EGFR mAb或Fab’),制备得到EGFR靶向免疫脂质体TLPD,针对抗体对脂质体粒径大小以及zeta电位的影响,对抗体类型、连接方式和投入量进行优化,结果发现抗体类型为Anti-EGFR Fab’,且采用传统连接方式连接的抗体时制备得到的脂质体TLPD-FC,平均粒径在150 nm~160 nm之间,zeta电位在10 mV左右,为后续实验研究奠定了基础。
     然后,通过SDS-PAGE实验证实抗体确实已经连接到脂质体,同时考察了Naked-LPD、NTLPD(PEG化非靶向脂质体)、TLPD-FC对siRNA结合能力、siRNA的包封率以及体外基因沉默效率。凝胶阻滞实验结果表明Naked-LPD、NTLPD、TLPD-FC对siRNA均具有较强的结合能力,通过超滤离心的方法证实了siRNA包封率高达90%,以上实验证实上述样品对siRNA很强的包裹能力,并且PEG化或者抗体修饰对siRNA包封率影响较小。体外基因沉默效率考查了抗体投入量不同时TLPD-FC(包括TLPD-FCA、TLPD-FCB、TLPD-FCC、TLPD-FCD)在MDA-MB-231细胞中的基因沉默效率,结果表明TLPD-FCC具有最高的基因沉默效率。
     最后,对TLPD-FCC的相关性质和体内外活性进行了深入的研究和探讨。通过透射电镜观察TLPD-FCC和NTLPD的形态大小发现,两者在形态和大小分布上没有明显区别,表明了抗体连接对脂质体的结构几乎没有影响。琼脂糖凝胶电泳实验证实了siRNA在TLPD-FCC或NTLPD的保护下血清稳定性良好。脂质体的血清稳定性通过动态光散射实验得到结论:与Naked LPD相比,NTLPD或TLPD-FCC在PEG的保护下不易与BSA相互作用,稳定性好。体外基因转染效率和基因沉默效率结果表明与NTLPD相比,TLPD-FCC具有较高的特异性的转染效率和基因沉默活性。随后,通过MDA-MB-231乳腺癌肿瘤模型的建立,免疫荧光标记实验证实了体内肿瘤细胞的EGFR表达水平,体内分布实验也验证了TLPD-FCC通过受体介导内吞机制,随着时间的变化在肿瘤部位高度聚集,达到峰值,且激光共聚焦结果显示,TLPD-FCC显示出比NTLPD更高的肿瘤细胞靶向特异性和结合能力及内吞效率。最终,体内基因沉默效率的考察结果表明TLPD-FCC具有比NTLPD更高的基因沉默效率,具有特异性的基因沉默活性。
     本研究制备得到的TLPD-FCC能有效地递送siRNA至高表达EGFR的乳腺癌细胞,并具有良好的体内外基因沉默效率,有可能作为一种治疗高表达EGFR乳腺癌的基因载体用于临床。
Gene therapy is recently considered as an effective way in treating both inherited and acquired diseases, especially malignant tumors. RNA interfering (RNAi), an efficient sequence specific gene silencing technology, has sparked an explosion of research in tumor gene therapy field. siRNA (small interfering RNA) is the effective molecule in the RNAi pathways, which is 21~23 bp nucleotide, double-stranded. It can specifically degrade complementary mRNA, thus inhibiting tumor associated gene expression, tumor progression, invasion and metastasis.
     However, siRNA cannot enter the tumor cells without the help of carriers and carrier is the main problem that hampers the development of gene therapy. So the investigation of the siRNA carrier is the hottest focus of tumor gene therapy. Cationic liposomes have been widely used as the non-viral carriers for siRNA delivery. They are non-toxic, naturally degradable, low-immunogenic and easy-to-produce generously. Recently, they attracted the serious attention of researcher.
     Previously our group is always going in for the research of preparation and characteristic of cationic liposome for siRNA delivery. We developed Lyophilized PEGylated Immunoliposomes (LPIL), according to PEGlyation, HER2 antibody modification and lyophilization. LPIL containing 2.5% PEG (2.5% PEG LPIL) can specifically delivering siRNA to HER2-overexpressing cancers and slience specific gene expression. As is reported, PEG can significantly enhance the stability of liposomes in plasma and prolong the in vivo half-life period. PEG is arranged in the brush mode with >8 mol% PEGylation for a 100 nm liposomal particle. The brush mode is the ideal configurations that ensures complete coverage of the surfaces of the nanoparticles providing full protection and have an excellent performance in vivo. However, the PEG content of LPIL was low, thus its in vivo application was hindered. Besides, LPIL cannot bear hight content of PEG owing to protect the physical stability of liposomes, and high content of PEG can not only destroy the stability of LPIL and also decrease the siRNA encapsulation efficiency. As a result, we should develop the novel cationic liposomes which possess hight content of PEG, siRNA encapsulation efficiency and good targeting. LPD (liposome-polycation-DNA) is a novel cationic liposomes for siRNA delivery. They composed of nucleic acids, a polycationic peptide and cationic liposome, and were prepared in a self-assembling process. This structure is different from the common liquid phase structure of liposomes, and is a negative core consisting of polycation, siRNA and DNA. More importantly, a post-insertion PEGlyation method was adopted, which provides a high siRNA encapsulation efficiency, liposome stability and was demonstrated to efficiently delivery siRNA to tumor cells. However, nobody investigate the characteristic and in vitro and in vivo activity of antibody-modified LPD. In this study, we finally obtained a final product TLPD-FCC which possesses high potent of PEG and antibody targeting, and investigated the siRNA encapsulation and in vitro and in vivo activity.
     Firstly, we prepared DOTAP/Chol (1:1 M ratio) cationic liposome, then mixed with protamine, calf thymus DNA, and siRNA in a self-assembling process to form naked LPD. NTLPD or TLPD was finally obtained from naked LPD by PEGlation, antibody modification, respectively. We investigated the effect of antibody type, conjugation strategy and amount on the essential physicochemical properties (such as size, charge, et al.) of liposomes. As a result, TLPD-FC (TLPD conjugated anti-EGFR Fab’with convetional strategy) which had a particle size between 150 and 160 nm, and the average zeta potential was near 10 mV, was used in the subsequent experiments.
     Secondly, we evaluated the presentation and integrity of Anti-EGFR Fab’on the surface of TLPD-FC by SDS-PAGE. Meanwhile, the siRNA binding af?nity of liposomes, siRNA encapsulation efficiency (EE) and the in vitro gene silencing were examined. Gel retardation assay result showed that naked LPD, NTLPD and TLPD-FC all had powerful binding af?nity to siRNA. The siRNA EE of liposomes was precisely calculated by subtracting unencapsulated siRNA from total siRNA. Consistent with results obtained in the gel retardation assay, the siRNA EE of all liposomes was very high(> 90%), indicating that naked LPD, NTLPD and TLPD-FC have potent encapsulation capacity to siRNA, and PEGylation and antibody conjugation have little adverse impact on siRNA EE for NTLPD and TLPD-FC. Accompanying with increased amount of conjugated antibody, the luciferase gene silencing activity of TLPD-FC in MDA-MB-231 cells gradually increased, TLPD-FCC possessed the best gene silencing activity among TLPD-FC (TLPD-FCA, TLPD-FCB, TLPD-FCC and TLPD-FCD) and was used in the subsequent experiments.
     Finally, we investigated the characteristic and in vitro and in vivo activity of TLPD-FCC. The size and morphology of liposomes were observed by TEM, which showed that there is no difference between NTLPD and TLPD-FCC in shape and size distribution, suggesting that antibody conjugation have little impact on the structure of liposomes. siRNA serum stability was detected by agarose gel electrophoresis, the result showed that siRNA in TLPD-FC and NTLPD was protected well in aqueous solution of 50% serum. The dynamic light scattering (DLS) showed the strong interaction exsited between naked LPD and bovine serum albumin (BSA), while NTLPD or TLPD-FC had little interaction with BSA and thus had a good stability. In vitro experiment, transfection efficiency and gene silencing were studied. TLPD-FCC possessed signi?cantly increased transfection ef?ciency and gene silencing activity compared with NTLPD. Subsequently, we successfully established EGFR-overexpressing tumor xenograft model, Immunofluorescence staining had been taken to show the high EGFR expression in MDA-MB-231 tumor tissues. In the IVIS imaging system, TLPD-FCC showed a much better accumulation and distribution in the tumor compared with NTLPD. Furthermore, in vivo uptake study showed that TLPD-FCC accumulated profusely throughout the tumors tissues in a pattern consistent with receptor-mediated endocytosis. However, NTLPD showed only minimal binding or uptake. Consistent with the in vitro gene silencing assay, TLPD-FCC showed significantly higher gene silencing activity in vivo than NTLPD.
     In this study, we obtained TLPD-FCC which could effectively deliver siRNA to EGFR-overexpressing cancer cells. Furthermore, TLPD-FCC showed a significantly enhanced EGFR targeting efficiency and gene silencing activity both in vitro and in vivo, which has the potential possibility to cure breast cancer in clinic.
引文
[1] de Fougerolles A, Vornlocher HP, Maraganore J, Lieberman J. Interfering with disease: a progress report on siRNA-based therapeutics. Nat Rev Drug Discov 2007; 6: 443-53.
    [2] Oh YK, Park TG. siRNA delivery systems for cancer treatment. Adv Drug Deliv Rev 2009; 61: 850-62.
    [3] Tseng YC, Mozumdar S, Huang L. Lipid-based systemic delivery of siRNA. Adv Drug Deliv Rev 2009; 61: 721-31.
    [4] Baker M. RNA interference: Homing in on delivery. Nature 2010; 22(464): 1225-8.
    [5] Morille M, Passirani C, Vonarbourg A, Clavreul A, Benoit JP. Progress in developing cationic vectors for non-viral systemic gene therapy against cancer. Biomaterials 2008; 29: 3477-96.
    [6] Gao J, Sun J, Li H, Liu W, Zhang Y, Li B, et al. Lyophilized HER2-specific PEGylated immμnoliposomes for active siRNA gene silencing. Biomaterials 2010; 31: 2655-64.
    [7] Li SD, Huang L, Stealth nanoparticles: High density but sheddable PEG is a key for tumor targeting. J Control Release 2010; 145(3): 178-81.
    [8] Chen Y, Zhu X, Zhang X, Liu B, Huang L. Nanoparticles modified with tumor-targeting scFv deliver siRNA and miRNA for cancer therapy. Mol Ther 2010; 18: 1650-6.
    [9] Pirollo KF, Rait A, Zhou Q, Hwang SH, Dagata JA, Zon G, et al. Materializing the potential of small interfering RNA via a tumor-targeting nanodelivery system. Cancer Res 2007; 67: 938-43.
    [10] Peer D, Park EJ, Morishita Y, Carman CV, Shimaoka M. Systemic leukocyte-directed siRNA delivery revealing cyclin D1 as an anti-inflammatory target. Science 2008; 319: 627-30.
    [11] Zheng X, Vladau C, Zhang X, Suzuki M, Ichim TE, Zhang ZX, et al. A novel in vivo siRNA delivery system specifically targeting dendritic cells and silencing CD40 genes for immunomodulation. Blood 2009; 113: 2646-54.
    [12] Mao HQ, Roy K, Troung-Le VL, Janes KA, Lin KY, Wang Y, et al. Chitosan-DNA nanoparticles as gene carriers: synthesis, characterization and transfection efficiency. J Control Release 2001; 70(3):399-421.
    [13] Gao J, Kou G, Wang H, Chen H, Li B, Lu Y, et al. PE38KDEL-loaded anti-HER2 nanoparticles inhibit breast tumor progression with reduced toxicity and immunogenicity. Breast Cancer Res Treat 2009; 115: 29-41.
    [14] Li SD, Huang L, Targeted delivery of antisense oligodeoxynucleotide and small interference RNA into lung cancer cells. Mol Pharm 2006; 3(5): 579-588.
    [15] Li SD, Chen YC, Hackett MJ, Huang L, Tumor-targeted delivery of siRNA by self-assembled nanoparticles. Mol Ther 2008; 16: 163.
    [16] Li SD, Chono S, Huang L. Efficient gene silencing in metastatic tumor by siRNA formulated in surface-modified nanoparticles. J Control Release 2008; 126: 77-84.
    [17] Buyens K, Demeester J, De Smedt SS, Sanders NN. Elucidating the encapsulation of short interfering RNA in PEGylated cationic liposomes. Langmuir 2009; 25: 4886-91.
    [18] Buyens K, Lucas B, Raemdonck K, Braeckmans K, Vercammen J, Hendrix J, et al. A fast and sensitive method for measuring the integrity of siRNA-carrier complexes in full human serum. J Control Release 2008; 126: 67-76.
    [19] Enback J, Laakkonen P, Tumor-homing peptides: Tools for targeting, imaging and destruction. Biochem. Soc. Trans.2007; 35: 780.
    [20] Park JW, Hong K, Kirpotin DB,et al. Anti-HER2 immunoliposomes: Enhanced ef?cacy attributable to targeted delivery. Clin Cancer Res. 2002; 8: 1172.
    [21] Wei Q, Kullberg EB, Gedda L, Trastuzumab-conjugated boron-containing liposomes for tumor-cell targeting; development and cellular studies. Int. J. Oncol. 2003; 23: 1159.
    [22] Cardoso AL, Simoes S, de Almeida LP, et al. siRNA delivery by a transferrin-associated lipid-based vector: A non-viral strategy to mediate gene silencing. J. Gene Med 2007; 9: 170.
    [23] Daniels TR, Ng PP, Delgado T, et al. Conjugation of an anti transferrin receptor IgG3-avidin fusion protein with biotinylated saporin results in signi?cant enhancement of its cytotoxicity against malignant hematopoietic cells. Mol. Cancer Ther 2007; 6: 2995.
    [24] Banerjee R, Tyagi P, Li SD, Huang L, Anisamide-targeted stealth liposomes: a potent carrier for targeting doxorubicin to human prostate cancer cells. Int. J. Cancer 2004; 112: 693.
    [25] Cheng J, Teply BA, Sherifi I, et al. Formulation of functionalized PLGA-PEG nanoparticles for in vivo targeted drug delivery. Biomaterials 2007; 28: 869.
    [26] Gao J, Feng SS, Guo Y. Antibody engineering promotes nanomedicine for cancer treatment. Nanomedicine (Lond) 2010; 5: 1141-5.
    [27] Liu Y, Li K, Liu B, Feng SS. A strategy for precision engineering of nanoparticles of biodegradable copolymers for quantitative control of targeted drug delivery. Biomaterials 2010; 31: 9145-55.
    [28] Mamot C, Drummond DC, GreiserΜ, Hong K, Kirpotin DB, Marks JD, et al. Epidermal growth factor receptor (EGFR)-targeted immunoliposomes mediate specific and efficient drug delivery to EGFR- and EGFRvIII-overexpressing tumor cells. Cancer Res 2003; 63: 3154-61.
    [29] Kim IY, Kang YS, Lee DS, Park HJ, Choi EK, Oh YK, et al. Antitumor activity of EGFR targeted pH-sensitive immunoliposomes encapsulating gemcitabine in A549 xenograft nude mice. J Control Release 2009;140: 55-60.
    [30] Arnaud Be duneaua, Patrick Saulnier, Franc-ois Hindre, Anne Clavreul, Jean-Christophe Lerouxc,Jean-Pierre Benoit. Design of targeted lipid nanocapsules by conjugation of whole antibodies and antibody Fab’fragments. Biomaterials 2007; 28: 4978-4990
    [31] Buse J, El-Aneed A. Properties, engineering and applications of lipid-based nanoparticle drug-delivery systems: current research and advances. Nanomedicine (Lond) 2010; 5: 1237-60.
    [32] Peer D, Karp JM, Hong S, Farokhzad OC, Margalit R, Langer R. Nanocarriers as an emerging platform for cancer therapy. Nat Nanotechnol 2007; 2: 751-60.
    [33] Matsumura Y, Maeda H, A new concept for macromolecular therapeutics in cancer chemotherapy: Mechanism of tumoritropic accumulation of proteins and the antitumor agent smancs. Cancer Res. 1986; 46: 6387.
    [34] Li SD, Huang L. Nanoparticles evading the reticuloendothelial system: role of the supported bilayer. Biochim Biophys Acta 2009; 1788: 2259-66.
    [35] Lee J, Cho EC, Cho K. Incorporation and release behavior of hydrophobic drug in functionalized poly( D, L-lactide )-block-poly(ethylene oxide) micelles. J Control Release 2004; 94: 323-35.
    [36] Schiffelers RM, Ansari A, Xu J, Zhou Q, Tang Q, Storm G, et al. Cancer siRNA therapy by tumor selective delivery with ligand-targeted sterically stabilized nanoparticle. Nucleic Acids Res 2004; 32: e149.
    [37] Aggarwal P, Hall JB, McLeland CB, Dobrovolskaia MA, McNeil SE. Nanoparticle interaction with plasma proteins as it relates to particle biodistribution, biocompatibility and therapeutic efficacy. Adv Drug Deliv Rev 2009; 61: 428-37.
    [38] Gao J, Kou G, Chen H, Wang H, Li B, Lu Y, et al. Treatment of hepatocellular carcinoma in mice with PE38KDEL type I mutant-loaded poly(lactic-co-glycolic acid) nanoparticles conjugated with humanized SM5-1 F(ab’) fragments. Mol Cancer Ther 2008; 7: 3399-407.
    [39] Mamot C, Drummond DC, Noble CO, Kallab V, Guo Z, Hong K, et al. Epidermal growth factor receptor-targeted immunoliposomes significantly enhance the efficacy of multiple anticancer drugs in vivo. Cancer Res 2005; 65: 11631-8.
    [40] Kirpotin DB, Drummond DC, Shao Y, Shalaby MR, Hong K, NielsenΜB, et al. Antibody targeting of long-circulating lipidic nanoparticles does not increase tumor localization but does increase internalization in animal models. Cancer Res 2006; 66: 6732-40.
    [41] Dass CR, Choong PF. Selective gene delivery for cancer therapy using cationic liposomes: in vivo proof of applicability. J Control Release 2006; 113: 155-63.
    [42] Hilgenbrink AR, Low PS. Folate receptor-mediated drug targeting: from therapeutics to diagnostics. J Pharm Sci 2005; 94: 2135-46.
    [1] ZHU L, LU Y, MILLER DD, et al. Structural and Formulation Factors In?uencing Pyridinium Lipid-Based Gene Transfer [J]. Bioconjugate Chem, 2008, 19(12): 2499-2512.
    [2] NICULESCU-DUVAZ D, HEYES J, SPRINGER CJ. Structure-Activity Relationship in Cationic Lipid Mediated Gene Transfection [J]. Curr Med Chem, 2003, 10(14): 1233-1261.
    [3] GHOSH YK, VISWESWARIAH SS, BHATTACHARYA S. Nature of linkage between the cationic headgroup and cholesteryl skeleton controls gene transfection efficiency [J]. FEBS Lett, 2000, 473(3): 341-344.
    [4] KIM BK, DOH K-O, NAM JH, et al. Synthesis of novel cholesterol-based cationic lipids for gene delivery [J]. Bioorg Med Chem Lett, 2009, 19(11): 2986-2989.
    [5] LV HT, ZHANG SB, WANG B. Toxicity of cationic lipids and cationic polymers in gene delivery [J]. J Control Release, 2006, 114(1): 100-109.
    [6] LEE Y, KOO H, LIM YB, et al. New cationic lipids for gene transfer with high efficiency and low toxicity: T-shape cholesterol ester derivatives [J]. Bioorg Med Chem Lett, 2004, 14(10): 2637-2641.
    [7] PISARCIK M, POLAKOVICOVA M, Pupak M, et al. Biodegradable gemini surfactants.Correlation of area per surfactant molecule with surfactant structure [J]. J Colloid Interface Sci, 2009, 329(1): 153-159.
    [8] LIU DL, QIAO WH, LI ZS, et al. Carbamate-linked cationic lipids for gene delivery [J]. Bioorg Med Chem, 2008, 16(2): 995-1005.
    [9] LIU DL,QIAO W H, LI ZS, et al. Synthetic Diether-linked Cationic Lipids for Gene Delivery [J]. Chem Biol Drug Des, 2006, 67(3): 248-251.
    [10] LIU DL, HU JJ, QIAO WH, et al. Synthesis and characterization of a series of carbamate-linked cationic lipids for gene delivery[J]. Lipids, 2005, 40 (8): 839-848.
    [11] LIU DL, HU JJ, QIAO WH, et al. Synthesis of carbamate-linked lipids for gene delivery [J]. Bioorg Med Chem Lett, 2005, 15(12): 3147-3150.
    [12] RAJESH M, SEN J, SRUJAN M, et al. Dramatic Influence of the Orientation of Linker between Hydrophilic and Hydrophobic Lipid Moiety in Liposomal Gene Delivery [J]. J Am Chem Soc, 2007, 129(37): 11408-11420.
    [13] ZHI DF, ZHANG SB, WANG B, et al. Transfection Efficiency of Cationic Lipids with Different Hydrophobic Domains in Gene Delivery [J]. Bioconjugate Chem, 2010(4): 563-577.
    [14] KIM HS, SONG IH, KIM JC, et al. In vitro and in vivo gene-transferring characteristics of novel cationic lipids, DMKD (O,O′-dimyristyl-N-lysylaspartate) and DMKE (O,O′-dimyristyl-N-lysyl glutamate) [J]. J Control Release, 2006, 115(8): 234-241.
    [15] FELGNER JH, KUMAR R, SRIDHAR CN, et al. Enhanced gene delivery and mechanism studies with a novel series of cationic lipid formulations [J]. J Biol Chem, 1994, 269(4): 2550-2561.
    [16] LIU DL, QIAO WH, LI ZS, et al. Structure–Function Relationship Research of Glycerol Backbone-Based Cationic Lipids for Gene Delivery [J]. Chem Biol Drug Des, 2008, 71(4): 336-344.
    [17] KOYNOVA R, TENCHOV B, WANG L, et al. Hydrophobic Moiety of Cationic Lipids Strongly Modulates Their Transfection Activity [J]. Mol Pharm, 2009, 6(3): 951-958.
    [18] YINGYONGNARONGKUL BE, RADCHATAWEDCHAKOON W, KRAJARNG A, et al. High transfection ef?ciency and low toxicity cationic lipids with aminoglycerol–diamine conjugate [J]. Bioorg Med Chem, 2009, 17(1): 176-188.
    [19] PINNADUWAGE P, SCHMITT L, Huang L, Use of a quaternary ammonium detergent in liposome mediated DNA transfection of mouse L-cells [J]. Biochim Biophys Acta, 1989, 985(1): 33-37.
    [20] CAMERON FH, MOGHADDAM MJ, BENDER VJ, et al. A transfection compound series based on a versatile Tris-linkage [J]. Biochim Biophys Acta, 1999, 1417(1): 37-50.
    [21] HEYES JA, NICULESCU-DUVAZ D, COOPER RG, et al. Synthesis of novel cationic lipids: effect of structural modification on the efficiency of gene transfer [J]. J Med Chem, 2002, 45(1): 99-114.
    [22] MAJETI BK, SINGH RS, YADAV SK, et al. Enhanced intravenous transgene expression in mouse lung using cyclic-head cationic lipids. [J]. Chem Biol, 2004, 11(4): 427-37.
    [23] NANTZ MH, DICUS CW, HILLIARD B, et al. The Bene?t of Hydrophobic Domain Asymmetry on the Ef?cacy of Transfection as Measured by in Vivo Imaging [J]. Mol Pharm, 2010,7(3): 786-794.
    [24] LOISEL S, FLOCH V, LE GC, et al. Factors in?uencing the ef?ciency of lipoplexes mediated gene transfer in lungs after intravenous administration [J]. Liposome Res, 2001, 11(2-3): 127-138.
    [25] ZUHORN IS, OBERLE V, VISSER WH, et al. Phase behavior of cationic amphiphiles and their mixtures with helper lipid in?uences lipoplex shape, DNA translocation, and transfection ef?ciency [J]. Biophys J, 2002, 83(4): 2096-2108.
    [26] KIM BK, DOH K-O, NAM JH, et al. Synthesis of novel cholesterol-based cationic lipids for gene delivery [J]. Bioorg Med Chem Lett, 2009, 19(11): 2986-2989.
    [27] ISLAM RU, HEAN J, OTTERLO WALV, et al. Ef?cient nucleic acid transduction with lipoplexes containing novel piperazine-and polyamine-conjugated cholesterol derivatives [J]. Bioorg MedChem Lett, 2009, 19(1): 100-103.
    [28] RAO NM.Cationic lipid-mediated nucleic acid delivery: beyond being cationic [J]. Chem Phys Lipids, 2010, 163(3): 245-252.
    [29] HAN S-E, SHIM KH, GA Y, et al. Novel cationic cholesterol derivative-based liposomes for serum-enhanced delivery of siRNA [J]. Int J Pharm, 2008, 353(1-2): 260-269.
    [30] Kim WJ, CHRISTENSEN LV, JO S, et al. Cholesteryl oligoarginine delivering vascular endothelial growth factor siRNA effectively inhibits tumor growth in colon adenocarcinoma [J]. Mol Ther, 2006, 14(3): 343-350.
    [31] REN T, SONG YK, ZHANG G, et al. Structural basis of DOTMA for its high intravenous transfection activity in mouse [J]. Gene Ther, 2000, 7(9): 764-768.
    [32] MCGREGOR C,PERRIN C,MONCK M,et al. Rational approaches to the design of cationic gemini surfactants for gene delivery [J]. J Am Chem Soc, 2001, 123(26): 6215-6220.
    [33] OBATA Y, SAITO S, TAKEDA N, et al. Plasmid DNA-encapsulating liposomes: Effect of a spacer between the cationic head group and hydrophobic moieties of the lipids on gene expression ef?ciency [J]. Biochim Biophys Acta, 2009, 1788(5): 1148-1158.
    [34] DELéPIN P,GUILLAUME EC, FLOCH V, et al. Cationic phosphonolipids as nonviral vectors: In vitro and in vivo applications [J]. J Pharm Sci, 2000, 89(5): 629-638.
    [35] FLOCH V, LOISEL S, GUENIN E, et al.Cation Substitution in Cationic Phosphonolipids: A New Concept To Improve Transfection Activity and Decrease Cellular Toxicity [J]. J Med Chem, 2000, 43(24): 4617-4628.
    [36] BAJAJ A,MISHRA SK, KONDAIAH P,et al.Effect of the headgroup variation on the gene transfer properties of cholesterol based cationic lipids possessing ether linkage [J]. Biochim Biophys Acta, 2008, 1778(5): 1222-1236.
    [37] CHEN YC, SEN J, BATHULA S R,et al.Novel Cationic Lipid That Delivers siRNA and Enhances Therapeutic Effect in Lung Cancer Cells [J]. Mol Pharm, 2009, 6(3): 696-705.
    [38] LI SD, HUANG L. In vivo gene transfer via intravenous administration of cationic lipid–protamine–DNA (LPD) complexes [J]. Gene Ther, 1997, 4(9): 891-900.
    [39] OBATA Y, SUZUKI D, TAKEOKA S, Evaluation of cationic assemblies constructed with amino acid based lipids for plasmid DNA delivery [J]. Bioconjug Chem, 2008, 19(5): 1055-1063.
    [40] MUKTHAVARAMA R, MAREPALLY S, VENKATA MY, et al. Cationic glycolipids with cyclic and open galactose head groups for the selective targeting of genes to mouse liver [J]. Biomaterials, 2009, 30(12): 2369-2384.
    [41] YAGI N, YANO Y, HATANAK K, et al. Synthesis and evaluation of a novel lipid–peptideconjugate for functionalized liposome [J]. Bioorg Med Chem Lett, 2007, 17(9): 2590-2593.
    [42] RUZZA P, BIONDI B, MARCHIANI A, et al.Cell-Penetrating Peptides: A Comparative Study on Lipid Affinity and Cargo Delivery Properties [J]. Pharmaceuticals, 2010, 3(4): 1045-1062.
    [43] RAO NM, GOPAL V, Cell Biological and Biophysical Aspects of Lipid-mediated Gene Delivery [J]. Biosci Rep, 2006, 26(4): 301-324.
    [44] PRATA CAH, ZHANG XX, LUO D, et al. Lipophilic Peptides for Gene Delivery [J]. Bioconjugate Chem, 2008, 19(2): 418-420.

© 2004-2018 中国地质图书馆版权所有 京ICP备05064691号 京公网安备11010802017129号

地址:北京市海淀区学院路29号 邮编:100083

电话:办公室:(+86 10)66554848;文献借阅、咨询服务、科技查新:66554700