Chan Wha Kim

Cationic solid lipid nanoparticles for co-delivery of paclitaxel and siRNA

In this study, we formulated cationic solid lipid nanoparticles (cSLN) for co-delivery of paclitaxel (PTX) and siRNA. 1,2-Dioleoyl-sn-glycero-3-ethylphosphocholine-based cSLN were prepared by emulsification solidification methods. PTX-loaded cSLN (PcSLN) were characterized by zeta potential and gel retardation of complexes with small interfering RNA (siRNA). The sizes of PcSLN did not significantly differ from those of empty cSLN without PTX (EcSLN). The use of cSLN increased the cellular uptake of fluorescent dsRNA in human epithelial carcinoma KB cells, with PcSLN complexed to fluorescence-labeled dsRNA promoting the greatest uptake. For co-delivery of therapeutic siRNA, human MCL1-specific siRNA (siMCL1) was complexed with PcSLN; luciferase-specific siRNA (siGL2) complexed to EcSLN or PcSLN was used as a control. MCL1 mRNA levels were significantly reduced in KB cells treated with siMCL1 complexed to PcSLN, but not in groups treated with siMCL alone or siGL2 complexed to PcSLN. siMCL1 complexed to PcSLN exerted the greatest in vitro anticancer effects in KB cells, followed by siMCL1 complexed to EcSLN, siGL2 complexed to PcSLN, PTX alone, and siMCL1 alone. In KB cell-xenografted mice, intratumoral injection of PcSLN complexed to siMCL1 significantly reduced the growth of tumors. Taken together, our results demonstrate the potential of cSLN for the development of co-delivery systems of various lipophilic anticancer drugs and therapeutic siRNAs.

Trilysinoyl oleylamide-based cationic liposomes for systemic co-delivery of siRNA and an anticancer drug.

Oligolysine-based cationic lipid derivatives were synthesized for delivery of siRNA, and formulated into cationic liposomes. Among various oligolysine-based lipid derivatives differing in lysine residue number and lipid moiety, trilysinoyl oleylamide (TLO)-based liposomes (TLOL) showed the highest delivery efficiency combined with minimal cytotoxicity. Delivery of siRNA using TLOL silenced target genes both in vitro and in vivo. In green fluorescent protein (GFP)-expressing tumor tissue, a significant reduction of fluorescence was observed after intratumoral administration of siGFP using TLOL compared with control siGL2. Intravenous administration of siMcl1 employing pegylated TLOL (pTLOL) reduced the expression of human Mcl1 protein in KB-xenografted tumor tissue. Despite the reduction in target protein Mcl1 expression following such systemic delivery, tumor growth was only slightly reduced compared to a siGL2-treated control group. To potentiate the anticancer activity of siMcl1, the anticancer drug suberoylanilide hydroxamic acid (SAHA) was additionally encapsulated in pTLOL. After intravenous administration of siMcl1 using SAHA-loaded pTLOL (pSTLOL), a significant reduction in tumor growth was observed compared to that seen in animals treated with free SAHA or siGL2 complexed with pSTLOL. The results indicate that pTLOL could be further developed as a systemic delivery system for synergistic anticancer siRNA and a drug.

Cationic drug-derived nanoparticles for multifunctional delivery of anticancer siRNA

Combined treatment of anticancer drugs and small interfering RNAs (siRNAs) have emerged as a new modality of anticancer therapy. Here, we describe a co-delivery system of anticancer drugs and siRNA in which anticancer drug-derived lipids form cationic nanoparticles for siRNA complexation. The anticancer drug mitoxantrone (MTO) was conjugated to palmitoleic acid, generating two types of palmitoleyl MTO (Pal-MTO) lipids: monopalmitoleyl MTO (mono-Pal-MTO) and dipalmitoleyl MTO (di-Pal-MTO). Among various lipid compositions of MTO, nanoparticles containing mono-Pal-MTO and di-Pal-MTO at a molar ratio of 1:1 (md11-Pal-MTO nanoparticles) showed the most efficient cellular delivery of siRNA, higher than that of Lipofectamine 2000. Delivery of red fluorescence protein-specific siRNA into B16F10-RFP cells using md11-Pal-MTO nanoparticles reduced the expression of RFP at both mRNA and protein levels, demonstrating silencing of the siRNA target gene. Moreover, delivery of Mcl-1-specific anticancer siRNA (siMcl-1) using md11-Pal-MTO enhanced antitumor activity in vitro, reducing tumor cell viability by 81% compared to a reduction of 68% following Lipofectamine 2000-mediated transfection of siMcl-1. Intratumoral administration of siMcl-1 using md11-Pal-MTO nanoparticles significantly inhibited tumor growth, reducing tumor size by 83% compared to untreated controls. Our results suggest the potential of md11-Pal-MTO multifunctional nanoparticles for co-delivery of anticancer siRNAs for effective combination therapy.

Cationic Liposomal Co-delivery of Small Interfering RNA and a MEK Inhibitor for Enhanced Anticancer Efficacy

PurposeTo test whether co-delivery of anticancer small interfering RNA (siRNA) and a chemical MEK inhibitor using cationic liposomes enhances anticancer activity in vitro and in vivo.MethodMEK inhibitor PD0325901 was encapsulated in lipid layers of N,N-dioleylglutamide-based cationic liposomes (DGL). Mcl1-specific siRNA (siMcl1) was complexed to DGL or PD0325901-loaded liposomes (PDGL). Efficiency of cellular siRNA delivery was tested using fluorescent double-stranded RNA. Silencing of target proteins was evaluated using Western blotting and real-time quantitative polymerase chain reactions. In vivo anticancer activity was tested using xenografted mice.ResultsSize and zeta potential of PDGL were similar to DGL. PDGL could deliver double-stranded RNA into cells with efficiencies comparable to DGL. Cellular co-delivery of siMcl1 and PD0325901 reduced expression of Mcl1 and pERK1/2 proteins and more effectively reduced tumor cell survival than other treatments. In mice, siMcl1 and PD0325901 co-delivered by PDGL inhibited growth of tumors 79%. Substantial apoptosis of tumor cells was observed following PDGL-mediated co-delivery of siMcl1, but not in other groups.ConclusionsPDGL-mediated co-delivery of siMcl1 and MEK inhibitor, PD0325901, could serve as a potential strategy for combination chemogene anticancer therapy.

Tocopheryl oligochitosan-based self assembling oligomersomes for siRNA delivery

Amphiphilic α-tocopherol oligochitosan conjugates were constructed by conjugating α-tocopherol succinate to water soluble oligochitosans with various molecular weights. In aqueous medium, the tocopherol oligochitosan conjugates self-assembled to single layered oligomersomes. The sizes of α-tocopherol-oligochitosan-based oligomersomes (TCOsomes) could be controlled by chain lengths of oligochitosans. The mean sizes of TCOsomes were 220 and 377 nm as the sizes of oligochitosans were 4000 and 12,500, respectively. For all TCOsomes formed in this study, polydispersity indexes were in the ranges of 0.111-0.256. Cryo-TEM images showed clear thickening in the unilamellar layer of TCOsomes upon complexation with siRNAs. Zeta potentials decreased as the ratios of siRNA/TCOsomes increased. TCOsomes self-assembled from tocopherol-oligochitosan 4K (TCOsome(4K)) significantly enhanced the cellular uptake of siRNAs (>98%), and reduced the expression of target proteins more effectively than did Lipofectamine 2000. In tumor xenografted mice, the intratumoral administration of siMcl-1 using TCOsomes substantially silenced the expression of Mcl-1 and prevented the growth of tumor. The hematoxylin-eosin staining showed the apoptosis of cells in the tissues of the mice treated with siMcl-1/TCOsome(4K) complexes, but not with siGL2/TCOsome(4K) complexes. The self-assembling and size-controllable oligomersomes might be suitable for effective in vivo delivery of siRNAs.

Enhanced Intrapulmonary Delivery of Anticancer siRNA for Lung Cancer Therapy Using Cationic Ethylphosphocholine-based Nanolipoplexes

n n Here, we report a cationic nanolipoplex as a pulmonary cellular delivery system for small-interfering RNA (siRNA). Six nanoliposomes differing in cationic lipids were formulated and screened in vitro and in vivo for cellular delivery functions in lung cells/tissues. Although the six nanoliposomes showed similar siRNA delivery efficiency in vitro, they exhibited significant differences in pulmonary cellular delivery functions in vivo. Among the various nanoliposomes, cationic dioleoyl-sn-glycero-3-ethylphosphocholine and cholesterol (ECL)-based nanoliposomes showed the highest pulmonary cellular delivery in vivo and the lowest cytotoxicity in vitro. The delivery efficiency of fluorescent siRNA in ECL nanoliposomes was 26.2-fold higher than that of naked siRNA in vivo. Treatment with Mcl1 (myeloid cell leukemia sequence 1)-specific siRNA (siMcl1) using ECL nanolipoplexes reduced target expression in B16F10 cell lines, whereas control, luciferase-specific siGL2 in ECL nanolipoplexes did not. In metastatic lung cancer mouse models induced by B16F10 or Lewis lung carcinoma (LLC) cells, intratracheal administration of siMcl1 in ECL nanolipoplexes significantly silenced Mcl1 mRNA and protein levels in lung tissue. Reduced formation of melanoma tumor nodules was observed in the lung. These results demonstrate the utility of ECL nanoliposomes for pulmonary delivery of therapeutic siRNA for the treatment of lung cancers and potentially for other respiratory diseases.n n

Tumor vasculature targeting following co-delivery of heparin-taurocholate conjugate and suberoylanilide hydroxamic acid using cationic nanolipoplex

The chemical conjugate of low molecular weight heparin with taurocholate (LHT7) was previously designed to offer anticancer activity while minimizing the anticoagulant activity. In the present study, we found that the systemic administration of LHT7 in nanolipoplex could substantially enhance tumor vasculature targeting and anticancer effects. Moreover, we found that co-delivery of LHT7 with suberoylanilide hydroxamic acid (SAHA), a histone deacetylase inhibitor, in nanolipoplex could provide synergistic antitumor effect. LHT7/SAHA nanolipoplex was formulated by encapsulating SAHA inside cationic liposomes, followed by complexation of negatively charged LHT7 onto the cationic surfaces of SAHA-loaded liposomes (SAHA-L). LHT7/SAHA nanolipoplex was positively charged with a mean diameter of 117.6 nm, and stable in serum. The nanolipoplex form of LHT7 could alter its pharmacokinetics and biodistribution. Compared to the free form of LHT7, LHT7 in the nanolipoplex showed 1.9-fold higher mean residence time, and higher tumor vasculature accumulation after its intravenous administration. LHT7/SAHA nanolipoplex showed highest antitumor efficacy in SCC-bearing mice, compared to LHT7, SAHA-L and sequential co-administration of LHT7 and SAHA-L. Consistent with the enhanced antitumor effect, the reduction of abnormal vessels in the tumor site was also the highest in the LHT7/SAHA nanolipoplex-treated group. These results suggested the potential of LHT7/SAHA nanolipoplex for enhanced tumor vasculature targeting, and the importance of nanolipoplex-mediated co-delivery with a histone deacetylase inhibitor for maximal anticancer effect.

Tetraiodothyroacetic acid-tagged liposomes for enhanced delivery of anticancer drug to tumor tissue via integrin receptor.

Nanoparticles have demonstrated potential for promoting drug delivery to tumor sites and enhancing uptake. Here, we report tetraiodothyroacetic acid (tetrac) as a promising new targeting moiety for delivery of anticancer drugs to tumor tissues. Tetrac, an antagonist that blocks the binding of thyroid hormone to integrin αvβ3, was covalently linked to the activated end of pegylated lipid and used to formulate tetrac-tagged pegylated liposomes (TPL). After incubating with TPL for 9h, cellular accumulation efficiency into A375 human melanoma cells, which express integrin αvβ3 at high density, was high (98.5%± 0.5% of cells), whereas that in KB cells, which express integrin at a very low density, was much lower (35.1%± 4.5%). Molecular imaging revealed that TPL preferentially distributed to tumor tissues after systemic administration in mice, where as non-targeting pegylated liposomes were distributed to tumors at background levels. Treatment with the alkyl lysophospholipid anticancer drug edelfosine, encapsulated in TPL, significantly reduced the survival of A375 tumor cells compared to cells treated with edelfosine in pegylated liposomes or with lysophosphatidylcholine encapsulated in TPL. Moreover, intravenous administration of edelfosine in TPL significantly reduced the growth of tumors and prolonged the survival of A375-xenografted mice, providing 100% protection for up to 50 days and some protection until 66 days (0% survival endpoint). In contrast, no untreated mice or mice treated with edelfosine-loaded pegylated liposomes survived up to 50 or 48 days, respectively, after tumor inoculation. These results suggest the potential of tetrac as a new ligand moiety for enhancing the delivery of anticancer drug-loaded nanoparticles to tumors and enhancing the therapeutic efficacy of encapsulated anticancer drugs.

Enhanced Transfection Rates of Small-Interfering RNA Using Dioleylglutamide-Based Magnetic Lipoplexes

Magnetic force-guided delivery (magnetofection) has been studied as a new modality for introducing small-interfering RNA (siRNA) into target cells, but its delivery efficiency needs to be improved. Here, we report that magnetofection of N,N-dioleylglutamide (DG)-based magnetic lipoplexes can substantially enhance the cellular delivery rates of siRNA. The siRNA was triply complexed with DG-based cationic liposomes and cationic iron-oxide nanoparticles. The formation of siRNA-containing magnetic lipoplexes was confirmed by gel retardation, sizes, and zeta potential values. Fluorescence microscopy and flow cytometry of fluorescent marker-labeled siRNA revealed that the DG-based magnetic lipoplexes conferred a higher cellular delivery rate of siRNA than DG-based lipoplexes or Lipofectamine 2000. In addition to the enhanced delivery of siRNA, the DG-based magnetic lipoplexes showed lack of cytotoxicity. We then tested the application of these magnetic lipoplexes for the cellular delivery of anticancer siRNA. Cancer cell lines magnetofected with DG-based magnetic lipoplexes containing Mcl1-specific siRNA (siMcl1) showed much lower viability than the groups treated with DG-based lipoplexes or Lipofectamine 2000, indicating that our magnetofection strategy conferred greater siMcl1-induced anticancer activity. These results suggest that DG-based magnetic lipoplexes are promising candidates for enhancing the efficiency of magnetic field-guided siRNA delivery.

Enhanced tumor localization and retention of chlorin e6 in cationic nanolipoplexes potentiate the tumor ablation effects of photodynamic therapy

Here we report the tumor ablation effects of the negatively charged photosensitizer chlorin e6 (Ce6) in nanocomplexes. Ce6 was complexed to cationic 1,2-dioleoyl-sn-glycero-3-ethylphosphocholine-based liposomes, forming cationic nanolipoplexes. The loading efficiency of Ce6 to cationic nanolipoplexes was greater than 90%. The degree of enhancement of cellular uptake of Ce6 by treatment in cationic nanolipoplexes increased with the concentration of Ce6, showing 18.3-fold higher uptake than free Ce6 at 15 µM. Molecular imaging revealed the preferential distribution and retention of Ce6 in SCC7 tumor tissues after intravenous administration of Ce6 in cationic nanolipoplexes. Moreover, localized illumination of mice receiving Ce6 in cationic nanolipoplexes resulted in the formation of thick scabs over tumor regions, and complete ablation of tumors after scab detachment. In contrast, continuous growth of tumors was observed in the group treated with free Ce6. Our results suggest that the cationic nanolipoplexes of Ce6 improve the therapeutic effects of photodynamic cancer therapy as compared to free Ce6.