Liposomal Delivery System Research Articles

Protective effect of antigen delivery using monoolein-based liposomes in experimental hematogenously disseminated candidiasis

We evaluated the potential of a liposomal antigen delivery system (ADS) containing Candida albicans cell wall surface proteins (CWSP) in mediating protection against systemic candidiasis. Treatment of bone-marrow-derived dendritic cells with CWSP-loaded dioctadecyldimethylammonium bromide:monoolein (DODAB:MO) liposomes enhanced and prolonged their activation comparatively to free antigen, indicating that liposome-entrapped CWSP were released more sustainable. Therefore, we immunized mice with CWSP either in a free form or loaded into two different DODAB:MO liposome formulations, respectively designated as ADS1 and ADS2, prior to intravenous C. albicans infection. Immunization with ADS1, but not with ADS2, conferred significant protection to infected mice, comparatively to immunization with CWSP or empty liposomes as control. ADS1-immunized mice presented significantly higher serum levels of C. albicans-specific antibodies that enhanced phagocytosis of this fungus. In these mice, a mixed cytokine production profile was observed encompassing IFN-γ, IL-4, IL-17A and IL-10. Nevertheless, only production of IL-4, IL-17 and IL-10 was higher than in controls. In this study we demonstrated that DODAB:MO liposomes enhance the immunogenicity of C. albicans antigens and host protection in a murine model of systemic candidiasis. Therefore, this liposomal adjuvant could be a promising candidate to assess in vaccination against this pathogenic fungus. Statement of SignificanceThis work describes the immunomodulation capacity of the previously validated antigen delivery system (ADS) composed by dioctadecyldimethylammonium bromide (DODAB) and monoolein (MO) lipids incorporating the cell wall surface proteins (CWSP) from C. albicans. Here, we not only present the ability of this system in facilitating antigen uptake by DCs in vitro, but also that this system induces higher levels of pro-inflammatory cytokines and opsonizing specific IgG antibodies in serum of mice immunized subcutaneously. We show that the ADS are efficient nanocarrier and modulate the immune response against intravenous C. albicans infection favoring mouse protection. In sum, we show that the incorporation of C. albicans antigens in DODAB:MO nanocarries are a promising vaccine strategy against C. albicans fungal infection.

Photothermally Triggered Lipid Bilayer Phase Transition and Drug Release from Gold Nanorod and Indocyanine Green Encapsulated Liposomes.

In light-activated liposomal drug delivery systems (DDSs), the light sensitivity can be obtained by a photothermal agent that converts light energy into heat. Excess heat increases the drug permeability of the lipid bilayer, and drug is released as a result. In this work, two near-IR responsive photothermal agents in a model drug delivery system are studied: either gold nanorods (GNRs) encapsulated inside the liposomes or indocyanine green (ICG) embedded into the lipid bilayer. The liposome system is exposed to light, and the heating effect is studied with fluorescent thermometers: laurdan and CdSe quantum dots (QDs). Both photothermal agents are shown to convert light into heat in an extent to cause a phase transition in the surrounding lipid bilayer. This phase transition is also proven with laurdan generalized polarization (GP). In addition to the heating results, we show that the model drug (calcein) is released from the liposomal cavity with both photothermal agents when the light power is sufficient to cause a phase transition in the lipid bilayer.

Neuroprotection against cerebral ischemia/reperfusion injury by intravenous administration of liposomal fasudil

Fasudil, a Rho-kinase inhibitor, is a promising neuroprotectant against ischemic stroke; however, its low bioavailability is an obstacle to be overcome. Our previous study revealed that the liposomal drug delivery system is a hopeful strategy to increase the therapeutic efficacy of neuroprotectants. In the present study, the usefulness of intravenously administered liposomal fasudil for cerebral ischemia/reperfusion (I/R) injury treatment was examined in transient middle cerebral artery occlusion (t-MCAO) rats. The results showed that PEGylated liposomes of approximately 100nm in diameter accumulated more extensively in the I/R region compared with those of over 200nm. Confocal images showed that fluorescence-labeled liposomal fasudil was widely distributed in the I/R region, and was not noticeably taken up by microglia, which are well-known resident macrophages in the brain, and neuronal cells. These data indicated that liposomal fasudil mainly exerted its pharmacological activity by releasing fasudil from the liposomes in the I/R region. Moreover, liposomal fasudil effectively suppressed neutrophil invasion and brain cell damage in the t-MCAO rats, resulting in amelioration of their motor function deficits. These findings demonstrated both the importance of particle size for neuroprotectant delivery and the effectiveness of liposomal fasudil for the treatment of cerebral I/R injury.

Xanthan Gum Coated Mucoadhesive Liposomes for Efficient Nose to Brain Delivery of Curcumin

Background: The objective of this study was to develop liposomal mucoadhesive drug delivery system for the delivery of curcumin via nasal route, to avoid hepatic first pass metabolism, to increase residence time and to investigate its nose to brain delivery potential. Methodology: The liposomes were prepared by solvent dispersion method using soya lecithin and cholesterol as a lipid phase and xanthan gum as a mucoadhesive polymer. The liposomes were evaluated for particle size, entrapment efficiency, mucoadhesion, DSC, ex vivo permeation, histopathological study, in vitro drug release, and in vivo study for the estimation of drug in brain after intranasal administration. Results and Discussion: The particle size was in the range of 100.2-150 nm with good stability and controlled release characteristics without any deleterious effect on nasal mucosa of rat. When administered via intranasal route the liposomes showed higher drug distribution in brain (1240 ng) compared to drug solution (65 ng). Conclusion: The results of the in vivo study suggests that the xanthan gum coated curcumin liposomes is a promising drug delivery system to deliver drug to the brain through nasal route. Keywords: Curcumin, liposomes, mucoadhesion, nose to brain delivery, solvent dispersion method, xanthan gum.

Hyaluronan-conjugated liposomes encapsulating gemcitabine for breast cancer stem cells.

Investigation of potential therapeutics for targeting breast cancer stem cells (BCSCs) is important because these cells are regarded as culprit of breast cancer relapse. Accomplishing this kind of strategy requires a specific drug-delivery system using the distinct features of liposomes. Studies on targeted liposomal delivery systems have indicated the conjugation of hyaluronan (HA), a primary ligand for CD44 surface markers, as an appropriate method for targeting BCSCs. For this study, enriched BCSCs were obtained by culturing MCF-7 breast cancer cells in nonadherent conditions. The enriched BCSCs were challenged with HA-conjugated liposomes encapsulating gemcitabine (2, 2-difluoro-2-deoxycytidine, GEM). In vitro study showed that the HA-conjugated liposomes significantly enhanced the cytotoxicity, anti-migration, and anti-colony formation abilities of GEM through targeting of CD44 expressed on BCSCs. In pharmacokinetic study, area under the drug concentration vs time curve (AUC) of the immunoliposomal GEM was 3.5 times higher than that of free GEM, indicating that the HA-conjugated liposomes enhanced the stability of GEM in the bloodstream and therefore prolonged its half-life time. The antitumor effect of the immunoliposomal GEM was 3.3 times higher than that of free GEM in a xenograft mouse model, probably reflecting the unique targeting of the CD44 receptor by HA and the increased cytotoxicity and stability through the liposomal formulation. Furthermore, marginal change in body weight demonstrated that the use of liposomes considerably reduced the systemic toxicity of GEM on normal healthy cells. Taken together, this study demonstrates that HA-conjugated liposomes encapsulating GEM show promise for the therapy of breast cancer in vitro and in a xenograft model by targeting the BCSCs.

Liposome intracellular delivery of Salvia miltiorrhiza Bge. deprivative DS-201 improves its BKCa channel-activating and vasorelaxing effects

Some drugs exert curative effects intracellularly, but their hydrophilic property prohibits the membrane-penetrating process and thus limits the curative efficacies, although this property guarantee their solubility in aqueous phase. An example is sodium tanshinone II-A sulfonate (DS-201), a derivative of Chinese medical herb Danshen (Salvia miltiorrhiza) which is a BKCa channel opener and a vasodilator. This study established and optimized a liposome delivery system which could pack and deliver DS-201 into HEK293 cells transfected with BKCa channels, and DS-201 given this way significantly increased the open probability of BKCa channel from baseline 0.013 ± 0.004 to 0.036 ± 0.011 at +40mV membrane potential (P<0.05) in single-channel attached study, and also increased the current density from baseline 23.2 ± 4.4 to 66.0 ± 15.2pA/pF at +40mV membrane potential (P<0.05), compared with the direct extracellular administration of this drug. Moreover, showing a ~60 % inhibition of the PE or PGF2a induced vascular constriction, the DS-201 liposomes did posses significantly enhanced vasorelaxant effect on rat mesenteric artery, compared with ~20 % inhibition of the directly administration of this drug (P<0.05), suggesting that DS-201 delivered by liposomes significantly improved the drug’s vasorelaxing effect. Taken together, the optimized DS-201 liposomes in our study successfully delivered DS-201 into cells and thus significantly activated BKCa channels to reverse the contraction induced by PE and PGF2α, attesting the enhanced bioavailability.

Insights in Diagnostic Biomarkers for Alzheimer’s Disease

Alzheimer’s disease is a chronic brain degenerative condition arising from increasing human aging population stemming high costs in the health system. Since post-mortem brain biopsy is regarded as the definitive diagnosis of AD, developing a non-invasive approach is highly valued. Current cutting-edge medical devices, liposomal and nanoparticle-drug delivery systems as well cerebrospinal fluid biomarkers and structural magnetic resonance imaging biomarkers have limited diagnostic benefits. Emerging genomics and proteomics biomarkers show encouraging results at distinguishing mild cognitive impairment converters to non-converters progressing to AD dementia. Multibiomarkers offer a better alternative by predicting on a short period those asymptomatic subjects who are more susceptible to progress into the prodromal stage. Other applications are currently investigating which medical conditions foster aging dementia. Since cardiovascular diseases have shown to advance the temporal stage of neurodegeneration and the extent of neuroanatomical damage, combining proteins associated with vascular diseases with current cerebrospinal fluid biomarkers enhances the diagnostic accuracy while others proteins can serve as staging biomarkers.

Barriers to Liposomal Gene Delivery: from Application Site to the Target.

Gene therapy is a therapeutic approach to deliver genetic material into cells to alter their function in entire organism. One promising form of gene delivery system (DDS) is liposomes. The success of liposome-mediated gene delivery is a multifactorial issue and well-designed liposomal systems might lead to optimized gene transfection particularly in vivo. Liposomal gene delivery systems face different barriers from their site of application to their target, which is inside the cells. These barriers include presystemic obstacles (epithelial barriers), systemic barriers in blood circulation and cellular barriers. Epithelial barriers differ depending on the route of administration. Systemic barriers include enzymatic degradation, binding and opsonisation. Both of these barriers can act as limiting hurdles that genetic material and their vector should overcome before reaching the cells. Finally liposomes should overcome cellular barriers that include cell entrance, endosomal escape and nuclear uptake. These barriers and their impact on liposomal gene delivery will be discussed in this review.

Rational design of liposomal drug delivery systems, a review: Combined experimental and computational studies of lipid membranes, liposomes and their PEGylation

Combined experimental and computational studies of lipid membranes and liposomes, with the aim to attain mechanistic understanding, result in a synergy that makes possible the rational design of liposomal drug delivery system (LDS) based therapies. The LDS is the leading form of nanoscale drug delivery platform, an avenue in drug research, known as “nanomedicine”, that holds the promise to transcend the current paradigm of drug development that has led to diminishing returns. Unfortunately this field of research has, so far, been far more successful in generating publications than new drug therapies. This partly results from the trial and error based methodologies used. We discuss experimental techniques capable of obtaining mechanistic insight into LDS structure and behavior. Insight obtained purely experimentally is, however, limited; computational modeling using molecular dynamics simulation can provide insight not otherwise available. We review computational research, that makes use of the multiscale modeling paradigm, simulating the phospholipid membrane with all atom resolution and the entire liposome with coarse grained models. We discuss in greater detail the computational modeling of liposome PEGylation. Overall, we wish to convey the power that lies in the combined use of experimental and computational methodologies; we hope to provide a roadmap for the rational design of LDS based therapies. Computational modeling is able to provide mechanistic insight that explains the context of experimental results and can also take the lead and inspire new directions for experimental research into LDS development. This article is part of a Special Issue entitled: Biosimulations edited by Ilpo Vattulainen and Tomasz Róg.

MRI-guided liposomes for targeted tandem chemotherapy and therapeutic response prediction

Liposomes are effective drug delivery systems that can be functionalized with imaging contrast agents, providing both diagnosis and monitoring of disease treatment. Here we describe the design of a theranostic liposomal drug delivery system whose biodistribution can be real time imaged by contrast enhanced MRI and can achieve tandem chemotherapy drug delivery. Because T1 relaxation of MRI depends upon the chemical structure of contrast agent as well as its interaction with neighbor environment, we rationally designed a functional liposome for in vivo T1 enhanced MRI. The liposome shows a 36-fold higher T1 relaxation rate over the commercial MRI contrast agent Omniscan® and a long circulation time up to 300min in vivo. Moreover, the multifunctional liposome carries both hydrophobic and hydrophilic chemotherapeutic drugs, can synergistically enhance therapeutic effects of multiple drugs and selectively deliver them to lung tumors, leading to lower doses, toxicity and sustained release. The nanoparticles, which exhibit favorable biodistributions to tumors, offer new possibilities for the simultaneous delivery of more than one drug and the evaluation of therapeutic response in vivo by T1 enhanced MRI. Statement of SignificanceCancer cells invoke different mechanisms to resist cancer therapies, particularly when delivering a single agent in a given therapy. The combination of two (or more) thermotherapy agents provides a promising way to circumvent such situations of drug resistance, due to a favorable synergistic effect that “tricks” the drug resistance mechanism.However, challenges to the simultaneous delivery of two drugs prevail, especially with regards to the simultaneous delivery of hydrophobic and hydrophobic drugs. Furthermore, non-invasive in vivo imaging of drug distribution enables the real-time monitoring and prediction of therapeutic responses to treatment.In this study, we rationally designed a theranostic liposomal drug delivery system whose biodistribution can be imaged via T1-weighted MRI in real-time and can achieve tandem chemotherapy drug delivery. This original study will be of considerable use to the wider drug delivery community.

Nanoparticle formulations of cisplatin for cancer therapy.

The genotoxic agent cisplatin, used alone or in combination with radiation and/or other chemotherapeutic agents, is an important first-line chemotherapy for a broad range of cancers. The clinical utility of cisplatin is limited both by intrinsic and acquired resistance and dose-limiting normal tissue toxicity. That cisplatin shows little selectivity for tumor versus normal tissue may be a critical factor limiting its value. To overcome the low therapeutic ratio of the free drug, macromolecular, liposomal, and nanoparticle drug delivery systems have been explored toward leveraging the enhanced permeability and retention effect and promoting delivery of cisplatin to tumors. Here, we survey recent advances in nanoparticle formulations of cisplatin, focusing on agents that show promise in preclinical or clinical settings. WIREs Nanomed Nanobiotechnol 2016, 8:776-791. doi: 10.1002/wnan.1390 For further resources related to this article, please visit the WIREs website.

Dual-functionalized liposomal delivery system for solid tumors based on RGD and a pH-responsive antimicrobial peptide.

[D]-H6L9, as a pH-responsive anti-microbial peptide (AMP), has been evidenced by us to be an excellent choice in tumor microenvironment-responsive delivery as it could render liposomes responsive to the acidified tumor microenvironment. However, [D]-H6L9-modified liposomes could not actively target to tumor area. Therefore, integrin αvβ3-targeted peptide RGD was co-modified with [D]-H6L9 onto liposomes [(R + D)-Lip] for improved tumor delivery efficiency. Under pH 6.3, (R + D)-Lip could be taken up by C26 cells and C26 tumor spheroids (integrin αvβ3-positive) with significantly improved efficiency compared with other groups, which was contributed by both RGD and [D]-H6L9, while RGD did not increase the cellular uptake performance on MCF-7 cells (integrin αvβ3-negative). Results showed that RGD could decrease cellular uptake of (R + D)-Lip while [D]-H6L9 could increase it, implying the role of both RGD and [D]-H6L9 in cellular internalization of (R + D)-Lip. On the other hand, (R + D)-Lip could escape the entrapment of lysosomes. PTX-loaded (R + D)-Lip could further increase the cellular toxicity against C26 cells compared with liposomes modified only with RGD and [D]-H6L9 respectively, and achieve remarkable tumor inhibition effect on C26 tumor models.

Lipoplexes for Gene Delivery Characterized by Fluorescence Correlation Spectroscopy

Liposomes composed of cationic lipids have been extensively investigated as drug delivery systems [1] and carrier for gene therapy and regenerative medicine as an alternative to viral approaches [2]. One exemplary regenerative medicine concept is the use of induced pluripotent stem cells (iPS) reprogrammed through the introduction of pluripotency genes such as OCT4, Sox2, KLF4 and c-Myc [3]. In this work, we study the complexation of adequate liposome formulations with these four genes through Fluorescence Cross-Correlation Spectroscopy (FCCS). [4]Liposomes stained with the carbocyanine dye 1,1-Dioctadecyl-3,3,3,3-tetramethylindodicarbocyanine (DiD) and fluorescently labelled plasmids carrying the OCT4, Sox2, KLF4 and c-Myc genes are characterized via single photon FCCS studies with a confocal microscope (LSM780, Zeiss, Oberkochen, Germany). Using CX-rhodamine and fluorescein as fluorescent labelling for the genes, we create two complementary wavelength windows to the far red wavelength window necessary to observe DiD fluorescence. Thereby, we create the possibility to monitor liposome loading with more than one gene.[1] Allen, T. M. & Cullis, P. R. Liposomal drug delivery systems: From concept to clinical applications. Adv. Drug Deliv. Rev. 65, 36-48 (2013).[2] Niidome, T. & Huang, L. Gene Therapy Progress and Prospects: Nonviral vectors. Gene Ther. 9, 1647-1652 (2002).[3] Takahashi, K. & Yamanaka, S. Induction of Pluripotent Stem Cells from Mouse Embryonic and Adult Fibroblast Cultures by Defined Factors. Cell 126, 663-676 (2006).[4] Merkle, D., Lees-Miller, S. P. & Cramb, D. T. Structure and Dynamics of Lipoplex Formation Examined Using Two-Photon Fluorescence Cross-Correlation Spectroscopy. Biochemistry 43, 7263-7272 (2004).

Formulation and advantages of furazolidone in liposomal drug delivery systems

Furazolidone has proven to have antiprotozoal and antibacterial activity. A number of literature supported its use against Helicobacter pylori. This potential application opens new prospects of its use in clinical settings in triple therapy. In order to avoid side effects associated with this drug, liposomal mucoadhesive drug delivery that can work locally in stomach is considered as an appropriate approach. This study is a focus on formulations and in vitro characterization of liposomes containing furazolidone. Therefore, the effects of variable amounts of drug and cholesterol on encapsulation efficacy and in vitro drug release were evaluated for different liposomal formulations. Mucoadhesive behavior of chitosan coated liposomal at two different pHs was also evaluated and increase in pH from 1.3 to 4.5 increased mucoadhesion from 42% to 60% respectively. Increasing the amount of drug from 4mg to 5mg increased encapsulation activity however, increasing the drug any further decreased encapsulation activity. In contrast, by increasing the amount of cholesterol decrease in encapsulation activity was observed. The optimized formulation with 5mg of drug and 53mg of cholesterol in formulation gave 57% drug release at pH 1.3 but release was increased up to 71% by increasing pH to 4.5 for same amount of drug. However, by using 10.6mg of cholesterol and 5mg of drug the overall release was increased at both pH conditions, at pH 1.3 release was 69% as compared to 77% at pH 4.5. This trend of drug release profile and mucoadhesion that favors pH 4.5 is documented as useful in targeting H. pylori as normal pH of stomach is expected to be higher by the influence of this microbe. Hence, the results of this research can be taken further into a future in vivo study.

Preparation of a Cyclic RGD: Modified Liposomal SiRNA Formulation for Use in Active Targeting to Tumor and Tumor Endothelial Cells.

The delivery of SiRNA is not only a challenging strategy for developing new remedies, but is also useful as an analytic tool for an in vivo phenotypic alteration by loss-of-function. Specifically, ligand-mediated SiRNA active targeting can be used to silence any gene in any organ of interest. In this chapter, we describe the preparation of an active targeting system to tumor endothelial cells (TECs) using liposomal SiRNA modified with cyclic RGD peptides. The procedure consists of essentially three steps: (1) the synthesis of a cyclic RGD peptide derivative, (2) SiRNA encapsulation into a liposomal delivery system, and (3) modification of liposomal SiRNA with a cyclic RGD derivative.

Magnetically triggered smart liposomes

Event Abstract Back to Event Magnetically triggered smart liposomes Md Shahriar Hossain1*, Boris Martinac2*, Jung Ho Kim1*, M Azam Ali3*, Mislav Mustapic1*, Yoshitaka Nakayama2* and Joseph Horvat1* 1 Institute for Superconducting and Electronic Materials, University of Wollongong, Science and Engineering, Australia 2 Victor Chang Cardiac Research Institute, Mechano Biology Laboratory, Australia 3 University of Otago, Department of Applied Science, New Zealand Introduction: The magnetic properties of superparamagnetic nanoparticles have been the subject of research for many years. Within the last decade there has been a rapidly growing interest for magnetic nanoparticles motivated by numerous existing and expected applications in biomedicine, like separation of magnetically tagged cells, targeted drug or radionuclide transport into the cells or tissues, contrast improvement in diagnostic MRI and magnetic hyperthermia (local destruction of tumour tissues by inductive heating), amongst many others. The use of magnetic nanoparticles as a drug delivering system is still defined by its biocompatibility and selective targeting to the desired cell or tissue under the guidance of external magnetic field. Advances in current technologies and the development of magnetic nanoparticles as drug delivery systems to deliver drugs to tumor hypoxic zones have fast-tracked in the past decade and led to the development of various magnetic nano-formulations such as liposomes, metallic/nonmetallic, and polymeric nanoparticles. In this study, we have developed superparamagnetic CoFe2O4 nanoparticles for binding to MscL. We show their lack of toxicity on a human cell culture. In addition, we demonstrate the activation of MscL by magnetic field in the presence of the superparamagnetic nanoparticles using patch fluorometry[1]. Materials and Methods: We developed superparamagnetic nanoparticles for activation of the MscL nanovalves by magnetic field. Synthesised CoFe2O4 nanoparticles with the radius less than 10 nm were labelled by SH groups for attachment to MscL. Liposomes made of azolectin (Sigma) were produced using the dehydration/rehydration method as reported previously (Delcour et al. 1989; Häse et al. 1995). Activation of MscL by magnetic field with the nanoparticles attached was examined by the patch clamp technique showing that the number of activated channels under ramp pressure increased upon application of the magnetic field. In addition, we have not observed any cytotoxicity of the nanoparticles in human cultured cells. Nano particles were also characterized by XRD, TEM, FTIR and MPMS. Results and Discussion: By recording the channel activity in patch clamp experiments we found that the number of activated channels increased upon application of the magnetic field in the presence of the nanoparticles, which was not the case in the absence of the magnetic field [Figure 1]. The nanoparticles coated with SH groups on their surface can bind to the cysteine residue of each subunit of the M42C MscL channel mutant by forming a disulphide bond, as previously shown in several EPR and FRET spectroscopic studies. Conclusion: In summary, our study indicates that superparamagnetic nanoparticles of average size of less than 6 nm coated with SH groups are highly suitable as components of a trigger mechanism for opening MscL nanovalves. Due to their very large open pore and property of being modulated by mechanical stimuli MscL channels present an ideal candidate for use as nanovalves in liposomal drug delivery. Consequently, a combination of MscL channels and the magnetic nanoparticles generated for this study holds promise for use in the development of “smart liposomes”, a new generation of liposomal drug delivery system.

リポソームDDSの魅力、疾患診断・治療へのチャレンジ （第8回 日本DDS学会奨励賞によせて）

リポソームDDSの魅力、疾患診断・治療へのチャレンジ （第8回 日本DDS学会奨励賞によせて）

Dual Receptor Recognizing Cell Penetrating Peptide for Selective Targeting, Efficient Intratumoral Diffusion and Synthesized Anti-Glioma Therapy.

Cell penetrating peptides (CPPs) were widely used for drug delivery to tumor. However, the nonselective in vivo penetration greatly limited the application of CPPs-mediated drug delivery systems. And the treatment of malignant tumors is usually followed by poor prognosis and relapse due to the existence of extravascular core regions of tumor. Thus it is important to endue selective targeting and stronger intratumoral diffusion abilities to CPPs. In this study, an RGD reverse sequence dGR was conjugated to a CPP octa-arginine to form a CendR (R/KXXR/K) motif contained tandem peptide R8-dGR (RRRRRRRRdGR) which could bind to both integrin αvβ3 and neuropilin-1 receptors. The dual receptor recognizing peptide R8-dGR displayed increased cellular uptake and efficient penetration ability into glioma spheroids in vitro. The following in vivo studies indicated the active targeting and intratumoral diffusion capabilities of R8-dGR modified liposomes. When paclitaxel was loaded in the liposomes, PTX-R8-dGR-Lip induced the strongest anti-proliferation effect on both tumor cells and cancer stem cells, and inhibited the formation of vasculogenic mimicry channels in vitro. Finally, the R8-dGR liposomal drug delivery system prolonged the medium survival time of intracranial C6 bearing mice by 2.1-fold compared to the untreated group, and achieved an exhaustive anti-glioma therapy including anti-tumor cells, anti-vasculogenic mimicry and anti-brain cancer stem cells. To sum up, all the results demonstrated that R8-dGR was an ideal dual receptor recognizing CPP with selective glioma targeting and efficient intratumoral diffusion, which could be further used to equip drug delivery system for effective glioma therapy.

Delivery of Plasmid DNA into Tumors by Intravenous Injection of PEGylated Cationic Lipoplexes into Tumor-Bearing Mice

For systemic injection of cationic liposome/plasmid DNA (pDNA) complexes (cationic lipoplexes), polyethylene glycol (PEG)-modification (PEGylation) of lipoplexes can enhance their systemic stability. In this study, we examined whether intravenous injection of PEGylated cationic lipoplexes into tumor-bearing mice could deliver pDNA into tumor tissues and induce transgene expression. PEGylation of cationic liposomes could prevent their agglutination with erythrocytes. However, when PEGylated cationic lipoplexes were injected intravenously into tumor-bearing mice, they accumulated in tumor vascular vessels and did not exhibit transgene expression in tumors with both poor and well-developed vascularization. Furthermore, PEGylated cationic lipoplexes of CpG- free pDNA could not increase transgene expression in tumors after intravenous injection. These results suggested that PEGylation could not extravasate cationic lipoplexes from vascular vessels in tumors and abolished transgene expression although it enhanced the systemic stability of cationic lipoplexes by avoiding interactions with blood components such as erythrocytes. Successful delivery of pDNA to tumors by PEGylated cationic liposomes will require a rational strategy and the design of liposomal delivery systems to overcome the issue associated with the use of PEG.

Development of a novel berberine-mediated mitochondria-targeting nano-platform for drug-resistant cancer therapy.

Recent studies have shown that targeting doxorubicin to mitochondria of tumor cells can bypass the multi-drug resistance problem and inhibit tumor growth. We previously discovered that the C-9th and C-13th position-alkylated berberine derivatives possess improved mitochondria-targeting activity compared to berberine. Therefore, we hypothesize that these alkylated berberine derivatives could be utilized as potential mitochondrial-targeting ligands by inserting the alkyl chain into the liposomal bilayer membrane during the preparation of liposomes. In this research, a berberine derivate (a 16-carbon aliphatic chain was introduced to the C-9th of berberine, 9-C16 berberine) was employed to prepare mitochondria-targeting doxorubicin-loaded folic acid-conjugated polyethylene glycol(PEGylated) liposomes (MT-FOL-PLS). The results of in vitro cytotoxicity and apoptosis-inducing studies revealed that MT-FOL-PLS showed the strongest cytotoxicity and apoptosis-inducing effects in drug resistant MCF-7/adr cells in comparison with free doxorubicin and regular liposomal doxorubicin. MT-FOL-PLS enhanced cellular uptake of doxorubicin up to 15-fold compared to free doxorubicin, and targeted doxorubicin to mitochondria. In vivo and ex vivo drug distribution studies showed that MT-FOL-PLS increased the drug distribution in tumor and the administration of MT-FOL-PLS to resistant MCF-7/adr cell mouse xenografts stopped tumor growth. Our results confirmed that alkylated berberines can be exploited as mitochondrial-targeting ligands to overcome cancer multi-drug resistance, further advancing the research on active targeting of liposome delivery systems in the treatment of resistant cancer.