Cationic Liposome Formulations Research Articles

IMMU-45. CUSTOMIZED LIPID NANOPARTICLES DELIVER NUCLEIC ACIDS TO IMMUNE CELLS IN BRAIN TUMORS

Abstract BACKGROUND Brain tumors are notoriously difficult to treat in part due to their isolation behind the blood brain barrier and their power to suppress antitumor immune responses. We have previously reported cationic liposome formulations capable of delivering immune modulatory nucleic acids to immune cells in various peripheral organs, but there is currently no reliable method to deliver nucleic acids into brain tumors without direct injection into the tumor site. OBJECTIVE Here, we report the development of a customized lipid nanoparticle to deliver immune modulatory nucleic acids to immune cells in brain tumors. APPROACH Cationic liposomes composed of varying lipid combinations were evaluated for their ability to deliver functional mRNA and siRNA to innate immune cells in vitro and in intracranial tumor models. Nucleic acids were labelled with Cy3 to monitor particle distribution in vivo. RESULTS Lipids composed of DOTAP and cholesterol selectively delivered mRNA and siRNA to intracranial GL261 and KR158b tumors. Interestingly, these particles selectively delivered these nucleic acids to CD45+ white blood cells with minimal delivery to CD45- tumor cells or normal brain tissue. Encapsulation of siRNA blocking programmed death ligand 1 (PDL1) significantly reduced PDL1 expression on innate immune cells in brain tumors, with the greatest effects on tumor-associated macrophages. Co-administration of systemic checkpoint blockade with intravenous administration of these lipid nanoparticles bearing PDL1 siRNA enabled systemic and intratumoral checkpoint blockade, leading to 37% long term survivorship in an otherwise fatal intracranial tumor model. CONCLUSIONS Our customized lipid nanoparticles enable potent intratumoral immune modulation via delivery of nucleic acids to immune cells in brain tumors.

EndoTAG-1 plus gemcitabine versus gemcitabine alone in patients with measurable locally advanced and/or metastatic adenocarcinoma of the pancreas failed on FOLFIRINOX treatment (NCT03126435).

TPS4669 Background: Pancreatic cancer (PC) is the 3rd deadliest cancer in the United State surpassing breast cancer in 2016, with the overall survival rate of - 9% for those newly diagnosed individuals. The notorious disease is set to become the 2nd leading cause of death from cancer by 2020 in US (National Cancer Institute, NIH). FOLFIRINOX regimen is one of the standard 1st-line treatments for PC patients with good performance status; however, there is currently no standard of care in 2nd-line therapy after FOLFIRINOX failure. EndoTAG-1 is a novel formulation of cationic liposomes embedded with Paclitaxel, which specifically displays antivascular and antiangiogenic activities. By binding and internalizing at tumor endothelial cells after intravenous administration, the cytostatic activity of paclitaxel will be targeted to the activated tumor endothelial cells. Methods: Eligible patients with measurable locally advanced and/or metastatic adenocarcinoma of the pancreas failed on FILFIRINOX treatment will be screened and randomized (1:1) into one of the two arms in the study (n=218). The primary endpoint of the study is overall survival (OS), with secondary endpoints include progression-free survival (PFS), objective response rate (ORR), duration of response (DOR) and quality of life (QoL). Arm A: EndoTAG-1 plus Gemcitabine: Patients will receive intravenous injection with EndoTAG-1 (22 mg/m2) twice weekly plus gemcitabine (1,000 mg/m2) once weekly for consecutively 3 weeks followed by 1 week rest. The treatment will be repeated every 4 weeks, with 8 weeks per cycle. The treatment will be kept until any one of the following occurs: progressive disease or unacceptable toxicity or withdrawal of consent. Arm B: Gemcitabine: Patients will receive gemcitabine (1,000 mg/m2) once weekly for consecutive 3 weeks followed by 1 week rest. The treatment will be repeated every 4 weeks, with 8 weeks per cycle. The treatment will be kept until any one of the following occurs: progressive disease or unacceptable toxicity or withdrawal of consent. The phase III trial began enrollment since November 2018. The trial will continue as planned from the last review in January 2020. Clinical trial information: NCT03126435 .

The cationic liposome CCS/C adjuvant induces immunity to influenza independently of the adaptor protein MyD88

ABSTRACT Traditional non-living vaccines are often least effective in the populations that need them most, such as neonates and elderly adults. Vaccine adjuvants are one approach to boost the immunogenicity of antigens in populations with reduced immunity. Ideally, vaccine adjuvants will increase the seroconversion rates across the population, lead to stronger immune responses, and enable the administration of fewer vaccine doses. We previously demonstrated that a cationic liposomal formulation of the commercial influenza split virus vaccine (CCS/C-HA) enhanced cellular and humoral immunity to the virus, increased seroconversion rates, and improved survival after live virus challenge in a preclinical model, as compared to the commercial vaccine as is (F-HA). We now evaluated vaccine efficacy in different strains and sexes of mice and determined the role of innate immunity in the mechanism of action of the CCS/C adjuvant by testing the response of mice deficient in Toll-like receptors or the TLR/IL-1 adaptor protein MyD88 following immunization with CCS/C-HA vs. F-HA. Although TLR2- and TLR4-deficient mice responded to F-HA immunization, F-HA immunization failed to engender a significant immune response in the absence of MyD88. In contrast, immunization with the CCS/C-HA vaccine overcame the requirement for MyD88 in the response to the commercial vaccine and improved the immune responses and seroconversion rates in all strains of mice tested, including those deficient in TLR2 and TLR4.

Intranasal Delivery and Transfection of mRNA Therapeutics in the Brain Using Cationic Liposomes.

Nucleic acid-based therapeutics, including the use of messenger RNA (mRNA) as a drug molecule, has tremendous potential in the treatment of chronic diseases, such as age-related neurodegenerative diseases. In this study, we have developed a cationic liposomal formulation of mRNA and evaluated the potential of intranasal delivery to the brain in murine model. Preliminary in vitro studies in J774A.1 murine macrophages showed GFP expression up to 24 h and stably expressed GFP protein in the cytosol. Upon intranasal administration of GFP-mRNA/cationic liposomes (3 mg/kg dose) in mice, there was significantly higher GFP-mRNA expression in the brain post 24 h as compared to either naked mRNA or the vehicle-treated group. Luciferase mRNA encapsulated in cationic liposomes was used for quantification of mRNA expression distribution in the brain. The results showed increased luciferase activity in the whole brain in a dose-dependent manner. Specifically, the luciferase-mRNA/cationic liposome group (3 mg/kg dose) showed significantly higher luciferase activity in the cortex, striatum, and midbrain regions as compared with the control groups, with minimal systemic exposure. Overall, the results of this study demonstrate the feasibility of brain-specific, nonviral mRNA delivery for the treatment of various neurological disorders.

Efficacy of three innovative bacterin vaccines against experimental infection with Mycoplasma hyopneumoniae

New vaccine formulations that include novel strains of Mycoplasma hyopneumoniae and innovative adjuvants designed to induce cellular immunity could improve vaccine efficacy against this pathogen. The aim of this experimental study was to assess the efficacy of three experimental bacterin formulations based on M. hyopneumoniae field strain F7.2C which were able to induce cellular immunity. The formulations included a cationic liposome formulation with the Mincle receptor ligand trehalose 6,6-dibehenate (Lipo_DDA:TDB), a squalene-in-water emulsion with Toll-like receptor (TLR) ligands targeting TLR1/2, TLR7/8 and TLR9 (SWE_TLR), and a poly(lactic-co-glycolic acid) micro-particle formulation with the same TLR ligands (PLGA_TLR). Four groups of 12 M. hyopneumoniae-free piglets were primo- (day (D) 0; 39 days of age) and booster vaccinated (D14) intramuscularly with either one of the three experimental bacterin formulations or PBS. The pigs were endotracheally inoculated with a highly and low virulent M. hyopneumoniae strain on D28 and D29, respectively, and euthanized on D56. The main efficacy parameters were: respiratory disease score (RDS; daily), macroscopic lung lesion score (D56) and log copies M. hyopneumoniae DNA determined with qPCR on bronchoalveolar lavage (BAL) fluid (D42, D56). All formulations were able to reduce clinical symptoms, lung lesions and the M. hyopneumoniae DNA load in the lung, with formulation SWE_TLR being the most effective (RDSD28–D56 −61.90%, macroscopic lung lesions −88.38%, M. hyopneumoniae DNA load in BAL fluid (D42) −67.28%). Further experiments raised under field conditions are needed to confirm these results and to assess the effect of the vaccines on performance parameters.

834TiP - A randomized controlled, open label, adaptive phase III Trial to evaluate safety and efficacy of endoTAG-1 plus gemcitabine versus gemcitabine alone in patients with measurable locally advanced and/or metastatic adenocarcinoma of the pancreas failed on FOLFIRINOX treatment

BackgroundPancreatic cancer (PC) is the 4th deadliest cancer in Europe, with more than 95% of those affected dying from the disease and is set to be the second greatest cause of death from cancer by 2020.(ECPC, European Cancer Patient Coalition) FOLFIRINOX regimen is the standard 1st-line treatment for PC patients with good performance status; however, there is still no standard of care in 2nd-line therapy for patients failed FOLFIRINOX. EndoTAG-1 is a novel formulation of cationic liposomes embedded with Paclitaxel, which specifically displays antivascular and antiangiogenic activity. By binding and internalizing at tumor endothelial cells after intravenous administration, the cytostatic and cytotoxic activities of paclitaxel are targeted to the activated tumor endothelial cells. Trial design•Patients with measurable locally advanced and/or metastatic adenocarcinoma of the pancreas failed on FOLFIRINOX treatment will be screened and randomized into one of the two arms in the study (n=218). •ArmA: EndoTAG-1 and Gemcitabine Patients will be administrated with EndoTAG-1 (22mg/m²) twice weekly plus gemcitabine (1000mg/m²) once weekly for 1 cycle (8 weeks), which consisting of 3 weeks of treatment and 1 week rest, followed by 3 weeks of treatment and 1 week rest. The treatment will be kept until any one of the following occurs: progressive disease or unacceptable toxicity or withdrawal of consent. •ArmB: Gemcitabine Patients will be administrated with Gemcitabine (1000mg/m²) once weekly for 1 cycle (8 weeks), which consisting of 3 weeks of treatment and 1 week rest, followed by 3 weeks of treatment and 1 week rest. The treatment will be kept until any one of the following occurs: progressive disease or unacceptable toxicity or withdrawal of consent. Clinical trial identificationNCT03126435, other study ID numbers:CT4006. Legal entity responsible for the studySynCore Biotechnology Co., Ltd. FundingSynCore Biotechnology Co., Ltd. DisclosureAll authors have declared no conflicts of interest.

Influence of lipid composition on the ability of liposome loaded voacamine to improve the reversion of doxorubicin resistant osteosarcoma cells.

The plant alkaloid voacamine (VOA) displays many interesting pharmacological activities thus, considering its scarce solubility in water, its encapsulation into liposome formulations for its delivery is an important goal. Different cationic liposome formulations containing a phospholipid, cholesterol and one of two diasteromeric cationic surfactants resulted able to maintain a stable transmembrane difference in ammonium sulfate concentration and/or pH gradient and to accumulate VOA in their internal aqueous bulk. The fluidity of the lipid bilayer affects both the ability to maintain a stable imbalance of protons and/or ammonium ions across the membrane and the entrapment efficiency. It was shown that VOA loaded into liposomes is more efficient than the free alkaloid to revert resistance of osteosarcoma cells resistant to doxorubicin to an extent depending on their composition.

Optimized combination of cationic lipids and neutral helper lipids in cationic liposomes for siRNA delivery into the lung by intravenous injection of siRNA lipoplexes

In this study, we examined the effect of neutral helper lipids in cationic liposomes on gene silencing efficacy in the lungs after intravenous injection of cationic liposomes/siRNA complexes (siRNA lipoplexes) into mice. We used 6 kinds of dialkyl or trialkyl cationic lipids as cationic lipids and prepared cationic liposomes composed of each cationic lipid with 1,2-dioleoyl-sn-glycero-3-phosphatidylethanolamine (DOPE), DOPE/cholesterol (Chol), or Chol. Regardless of the type of cationic lipid in the cationic liposomes, the increase in Chol content in the formulation decreased the in vitro gene silencing efficacy, and it increased siRNA accumulation in the lungs after intravenous injection of siRNA lipoplexes. However, gene silencing efficacies in the lungs were not greatly affected by the type of neutral helper lipid in cationic liposomes composed of cationic lipids with saturated dialkyl chains (C16–C18), although they were increased by the inclusion of Chol into formulations of cationic liposomes composed of cationic lipids with unsaturated dialkyl chains (C18). These findings indicated that siRNA biodistribution and in vivo knockdown efficiency after the intravenous injection of siRNA lipoplexes were strongly affected by combination of a cationic lipid and neutral helper lipid in cationic liposomes.

Comparative Analysis of Protein Quantification Methods for the Rapid Determination of Protein Loading in Liposomal Formulations.

Advances in manufacturing processes provide the ability for the high throughput production of liposomes containing a range of moieties, from small molecules to large biologicals (including proteins and nucleic acids for prophylactic and therapeutic applications). Whilst rapid quantification methods for small molecules are generally well established, the ability to rapidly quantify liposomal entrapment of proteins is limited. Indeed, most standard protein quantification techniques (including the BCA assay and Reverse phase-high performance liquid chromatography (RP-HPLC)) measure protein encapsulation indirectly, by measuring the amount of non-incorporated drug, and subtracting from the initial amount of protein added. However, this can give inaccurate and misrepresentative results. To address this, we have developed a range of methods to directly quantify protein entrapment within liposomes. The encapsulation efficiency within neutral, anionic and cationic liposome formulations was determined by three techniques; BCA assay, RP-HPLC and HPLC coupled to an evaporative light scattering detector, (HPLC-ELSD). All three methods are reliable for the quantification of protein, with linear responses and correlation coefficients of 0.99, and LOQ for all three methods being less than 10 µg/mL. Here within, we provide three methods for the rapid and robust quantification of protein loading within liposomal (and other bilayer) vesicle systems.

Effect of molecular crowding on the biological identity of liposomes: an overlooked factor at the bio-nano interface.

Once embedded in a physiological environment, the surface of nanoparticles (NPs) gets covered with a biomolecular corona (BC) that alters their synthetic characteristics and subsequently gives them a peculiar biological identity. Despite recent studies having clarified the role of NP composition, surface chemistry and biological source (e.g., human/animal serum or plasma) in the formation of the BC, little is known about the possible impact of molecular crowding. To fill this gap, we used a cationic liposomal formulation as a model system and studied its biological identity upon incubation with human plasma, at a fixed liposome-to-plasma volume ratio and different concentrations. We carried out dynamic light scattering measurements to quantify the size and zeta potential of the investigated systems and gel electrophoresis to evaluate the composition of the corresponding coronas. Our findings suggest that NP stability may be compromised by molecular crowding, but the corona composition is stable over a wide range of concentrations, which extend over more than two orders of magnitude. As the biological identity of NPs eventually determines their final fate in vivo, we predict that this study could contribute to the development of a safe and effective nanosystem for the targeted delivery of therapeutic agents.

O desafio de novas vias de administração para Anfotericina B

Leishmaniasis represents a group of diseases with a great clinical and epidemiological diversity, it is classified in two main forms: cutaneous and visceral. A prevalence of 12 million cases is estimated worldwide and this number continues to increase, with 1.5 to 2 million new cases per year, especially in tropical and subtropical areas. Amphotericin B (AmB) is a poorly water-soluble drug and poorly absorbed in the gastrointestinal tract. It is used in first-line treatment for invasive fungal infections and is the most potent commercially available leishmaniasis drug. All drug formulations available are administered parenterally, which hampers their viability at remote sites. In addition, the conventional formulation of AmB shows high nephrotoxicity. The lipid formulation have less side effect, but have the same efficacy. Because of this, there is a growing search for new formulations of AmB, with emphasis on intravenous cationic liposomal formulations and lipid nanoformulations, such as oral self-emulsifying delivery systems. Some of these oral formulations are already in clinical trials, being a hope in the treatment of fungal diseases and leshimaniasis.

Preclinical studies for a cationic liposome formulation containing Il-2 Intended for the treatment of Human Tumors

Preclinical studies for a cationic liposome formulation containing Il-2 Intended for the treatment of Human Tumors

Drug-fortified liposomes as carriers for sustained release of NSAIDs: The concept and its validation in the animal model for the treatment of arthritis

Drug-fortified cationic liposomes of 6‑methoxy‑2‑naphthylacetic acid (6‑MNA) were prepared and characterized by various techniques. The residence time of drug-fortified liposomes in joint cavity was evaluated by intra-articular (IA) administration of the radio-labeled (99mTc) liposomal formulation in the inflamed joints in rats. The cationic liposomal formulation composed of 6‑MNA (3) as an active agent, its double salt (4) with the lipid 1,2‑distearoyl‑sn‑glycero‑3‑phosphoethanolamine (DSPE), and pharmaceutically acceptable excipients such as hydrogenated soyabean phospatidylcholine (HSPC) and 1,2‑dioleyloxy‑3‑trimethylammoniumpropane chloride (DOTAP) were developed using thin film hydration technique. The cryo-TEM analysis confirmed that the prepared optimized liposomal formulation (DFL-2) was a mixture of small unilamellar vesicles (SUVs), large unilamellar vesicles (LUVs) and multilamellar vesicles (MLVs). In addition, the TEM analysis confirmed that the prepared liposomes were of spherical in shape having liposome size in the range of 500–900 nm and zeta potential of about +30 mV. The developed cationic liposomes exhibited sustained release profile of payload of 6‑MNA for over >12 h and about five times higher retention in the inflamed animal joints after 24 h (by scintigraphy of the joints) as compared to the plain 6‑MNA solution when administered by IA route. The anti-inflammatory activity of prepared liposomal composition is evaluated by Freund's adjuvant induced arthritic model in rats. The liposomal formulation was well tolerated by all animals indicating good biocompatibility. Further, the cationic liposomal formulation treated group showed decreased erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) level in comparison to the control and the standard groups in the in vivo study. The improved efficacy of the drug-fortified liposomal formulation was due to the coupled effect of longer retention and sustained release of the active drug 6‑MNA in the joints. From the obtained results it could be concluded that the combined effect of the cationic charge on the drug-fortified liposomes and the inherent affinity of the active agent towards the synovial joint tissues, coupled with slow release of the active drug due to double salt approach at the site of administration could potentially decrease the frequency of IA drug administration. Hence such a formulation could prove to be a therapeutic boon for the management of late stage arthritis.

Brain Targeting by Liposome-Biomolecular Corona Boosts Anticancer Efficacy of Temozolomide in Glioblastoma Cells.

Temozolomide (TMZ) is the current first-line chemotherapy for treatment of glioblastoma multiforme (GBM). However, similar to other brain therapeutic compounds, access of TMZ to brain tumors is impaired by the blood-brain barrier (BBB) leading to poor response for GBM patients. To overcome this major hurdle, we have synthesized a set of TMZ-encapsulating nanomedicines made of four cationic liposome (CL) formulations with systematic changes in lipid composition and physical-chemical properties. The targeting nature of this nanomedicine is provided by the recruitment of proteins, with natural targeting capacity, in the biomolecular corona (BC) layer that forms around CLs after exposure to human plasma (HP). TMZ-loaded CL-BC complexes were thoroughly characterized by dynamic light scattering (DLS), electrophoretic light scattering (ELS), and nanoliquid chromatography tandem mass spectrometry (nano-LC MS/MS). BCs were found to be enriched of typical BC fingerprints (BCFs) (e.g., Apolipoproteins, Vitronectin, and vitamin K-dependent protein), which have a substantial capacity in binding to receptors that are overexpressed at the BBB (e.g., scavenger receptor class B, type I and low-density lipoprotein receptor). We found that the CL formulation exhibiting the highest levels of targeting BCFs had larger uptake in human umbilical vein endothelial cells (HUVECs) that are commonly used as an in vitro model of the BBB. This formulation could also deliver TMZ to the human glioblastoma U-87 MG cell line and thus substantially enhance their antitumor efficacy compared to corona free CLs. Thus, we propose that the BC-based nanomedicines may pave a more effective way for efficient treatment of GBM.

Exploring membrane permeability of Tomatidine to enhance lipid mediated nucleic acid transfections

Intracellular delivery of nucleic acids is one of the critical steps in the transfections. Prior findings demonstrated various strategies including membrane fusion, endosomal escape for the efficient cytoplasmic delivery. In our continuing efforts to improve the nucleic acids transfections, we harnessed cell permeable properties of Tomatidine (T), a steroidal alkaloid abundantly found in green tomatoes for maximizing intracellular delivery of lipoplexes. We doped Tomatidine into liposomes of cationic lipid with amide linker (A) from our lipid library. Six liposomal formulations (AT) of Lipid A (1 mM) with varying concentrations of Tomatidine (0–1 mM) were prepared and evaluated for their transfection efficacies. Owing to its signature characteristic of cell membrane permeability, Tomatidine modulated endocytosis process, enhanced the intracellular delivery of the lipoplexes, and in turn increased the transfection efficacy of cationic liposomes. Our findings provide ‘proof of concept’ for enhancing transfections in gene delivery applications with Tomatidine in cationic liposomal formulations. These findings can be further applied in lipid mediated gene therapy and drug delivery applications.

The role of nanoliposome bilayer composition containing soluble leishmania antigen on maturation and activation of dendritic cells.

Objective(s):Dendritic cells (DCs) play a critical role in activation of T cell responses. Induction of type1 T helper (Th1) immune response is essential to generate protective immunity against cutaneous leishmaniasis. The intrinsic tendency of liposomes to have interaction with antigen-presenting cells is the main rationale to utilize liposomes as antigen carriers. In the present study, the effect of lipid phase transition temperature on DCs maturation and liposome uptake by murine bone marrow derived dendritic cells and human monocyte derived dendritic cells was investigated.Materials and Methods:Two cationic liposomal formulations consisting of DOTAP and DSPC/DOTAP were prepared and contained soluble leishmania antigen. Liposomes were incubated with immature or mature DCs derived from bone marrow (BMDCs) of C57BL/6 (which are resistant to cutaneous leishmaniasis), BALB/c mice (susceptible to cutaneous leishmaniasis) or DCs derived from human monocytes (MoDCs). The expression of DCs co-stimulatory markers and liposomal uptake were evaluated by flow cytometry method.Results:DCs which were encountered to liposomes consisting of DSPC showed significantly more expression of co-stimulatory molecules in cells from both human and C57BL/6 mice but not in cells from BALB/c mice.Conclusion:It is concluded that cationic liposomes consisting of DSPC are an effective adjuvant for antigen delivery in case of MoDCs and BMDCs from C57BL/6 mice. Moreover, DCs from different origins act differently in uptake of liposomes.

Development of a novel cationic liposome: Evaluation of liposome mediated transfection and anti-proliferative effects of miR-101 in acute myeloid leukemia

In this study, a new formulation of miRNA-loaded cationic liposomes (CLs) was prepared for bone marrow cells. CLs and miRNA-loaded cationic liposomes (CL/miR-101) were prepared and their characteristics were assessed using Dynamic light scattering (DLS) technique. MTT assay was used for bone marrow cell lines (KG-1 and HBMF-SPH cell lines) to evaluate cytotoxicity of CLs and CL/miR-101. The results have shown that the size and charge of the prepared CLs with new formulation were 84.5 nm and 20.1 mV and for CL/miR-101 were 126.6 nm and 4.31 mV. MTT assay results have demonstrated that different concentrations of CLs had no obvious cytotoxicity in both KG-1 and HBMF-SPH cells. The cytotoxicity of CL/miR-101 was approximately 12% more than the bare miRNA-101 in KG-1 cells and comparatively less significant amount of cytotoxicity was seen in HBMF-SPH cells. In this study, a new formulation of cationic liposome was successfully designed to deliver miRNA into bone marrow cells effectively. The suitable size and charge of CLs made them capable to form efficient CL/miR-101 complex, which was stable and penetrated significantly into the cells. CL/miR-101 complex proved to be cytotoxic for cancer cells and hence can be considered as a novel gene therapy system.

Precision design of nanomedicines to restore gemcitabine chemosensitivity for personalized pancreatic ductal adenocarcinoma treatment

Low chemosensitivity considerably restricts the therapeutic efficacy of gemcitabine (GEM) in pancreatic cancer treatment. Using immunohistochemical evaluation, we investigated that decreased expression of human equilibrative nucleoside transporter-1 (hENT1, which is the major GEM transporter across cell membranes) and increased expression of ribonucleotide reductase subunit 2 (RRM2, which decreases the cytotoxicity of GEM) was associated with low GEM chemosensitivity. To solve these problems, we employed a nanomedicine-based formulation of cationic liposomes for co-delivery of GEM along with siRNA targeting RRM2. Due to the specific endocytic uptake mechanism of nanocarriers and gene-silencing effect of RRM2 siRNA, this nanomedicine formulation significantly increased GEM chemosensitivity in tumor models of genetically engineered Panc1 cells with low hENT1 or high RRM2 expression. Moreover, in a series of patient-derived cancer cells, we demonstrated that the therapeutic benefits of the nanomedicine formulations were associated with the expression levels of hENT1 and RRM2. In summary, we found that the essential factors of GEM chemosensitivity were the expression levels of hENT1 and RRM2, and synthesized nanoformulations can overcome these problems. This unique design of nanomedicine not only provides a universal platform to enhance chemosensitivity but also contributes to the precision design and personalized treatment in nanomedicine.

RBIO-05. DOWNREGULATION OF H-FERRITIN EXPRESSION USING MULTIVALENT CATIONIC LIPOSOMES RESULTS IN INCREASED RADIATION SENSITIVITY IN PATIENT DERIVED GLIOMA INITIATING CELLS

AbstractGlioblastoma multiforme (GBM) is the most prevalent, lethal, malignant and refractory primary brain tumor with a very dismal survival rate. The glioma initiating cell (GIC) population within GBMs has been associated with treatment resistance and subsequently been implicated in tumor recurrence. Studies from our lab had previously shown that expression of the heavy chain subunit of the iron storage protein ferritin, H-ferritin, is essential for the survival and therapeutic resistance of non-stem glioma cells. Since H-ferritin is overexpressed in GICs, we hypothesized that downregulating its expression in these cells would lead to increased radiosensitivity. We therefore developed a novel strategy to sensitize these recalcitrant GICs to radiation therapy using a multivalent cationic liposome formulation that could efficiently transfect and deliver H-ferritin siRNA to GICs in vitro. Using patient derived T3691 CD133+ GICs we showed that downregulating H-ferritin led to a reduction in cell viability compared to controls upon being radiated at 4Gy and 8Gy dosage. Additionally these cells also showed an increased expression of the DNA damage response protein phospho-ϒH2AX upon radiation over controls. Thus, we have demonstrated that loss of H-ferritin in GICs leads to increased radiation sensitivity. Ongoing studies are focused on delineating the mechanisms through which H-ferritin loss mediates this effect in GICs.

In vitro and In vivo Studies on a Novel Bioadhesive Colloidal System: Cationic Liposomes of Ibuprofen.

The objective of this study was to develop an ocular drug delivery system built on the cationic liposomes, a novel bioadhesive colloidal system, which could enhance the precorneal residence time, ocular permeation, and bioavailability of ibuprofen. The optimal formulation of cationic liposomes prepared by ethanol injection method was ultimately confirmed by an orthogonal L9 (33) test design. In addition, γ-scintigraphic technology and the microdialysis technique were utilized in the assessment of in vivo precorneal retention capability and ocular bioavailability individually. In the end, we acquired the optimal formulation of ibuprofen cationic liposomes (Ibu-CL) by orthogonal test design, and the particle size and entrapment efficiency (EE%) were 121.0±3.5nm and 72.9±3.4%, respectively. In comparison to ibuprofen eye drops (Ibu-ED), Ibu-CL could significantly prolong the T max to 100min and the AUC to 1.53-folds, which indicated that the Ibu-CL could improve the precorneal retention time and bioavailability of ibuprofen. Consequently, these outcomes designated that the ibuprofen cationic liposomes we researched probably are a promising application in ocular drug delivery system.