rHDL Nanoparticles Research Articles

Reconstituted HDL ameliorated renal injury of diabetic kidney disease in mice.

Diabetic kidney disease (DKD) is a devastating kidney disease and lacks effective therapeutic interventions. The present study was aimed to determine whether reconstituted high-density lipoprotein (rHDL) ameliorated renal injury in eNOS-/- dbdb mice, a mouse model of DKD. Three groups of mice, wild type C57BLKS/J (non-diabetes), eNOS-/- dbdb (diabetes), and eNOS-/- dbdb treated with rHDL (diabetes+rHDL) with both males and females were used. The rHDL nanoparticles were administered to eNOS-/- dbdb mice at Week 16 at 5 μg/g body weight in ~100 μL of saline solution twice per week for 4 weeks via retroorbital injection. We found that rHDL treatment significantly blunted progression of albuminuria and GFR decline observed in DKD mice. Histological examinations showed that the rHDLs significantly alleviated glomerular injury and renal fibrosis, and inhibited podocyte loss. Western blots and immunohistochemical examinations showed that increased protein abundances of fibronectin and collagen IV in the renal cortex of eNOS-/- dbdb mice were significantly reduced by the rHDLs. Taken together, the present study suggests a renoprotective effect of rHDLs on DKD.

Photophysical Characterization and In Vitro Evaluation of α-Mangostin-Loaded HDL Mimetic Nano-Complex in LN-229 Glioblastoma Spheroid Model.

Cytotoxic activity has been reported for the xanthone α-mangostin (AMN) against Glioblastoma multiforme (GBM), an aggressive malignant brain cancer with a poor prognosis. Recognizing that AMN's high degree of hydrophobicity is likely to limit its systemic administration, we formulated AMN using reconstituted high-density lipoprotein (rHDL) nanoparticles. The photophysical characteristics of the formulation, including fluorescence lifetime and steady-state anisotropy, indicated that AMN was successfully incorporated into the rHDL nanoparticles. To our knowledge, this is the first report on the fluorescent characteristics of AMN with an HDL-based drug carrier. Cytotoxicity studies in a 2D culture and 3D spheroid model of LN-229 GBM cells and normal human astrocytes showed an enhanced therapeutic index with the rHDL-AMN formulation compared to the unincorporated AMN and Temozolomide, a standard GBM chemotherapy agent. Furthermore, treatment with the rHDL-AMN facilitated a dose-dependent upregulation of autophagy and reactive oxygen species generation to a greater extent in LN-229 cells compared to astrocytes, indicating the reduced off-target toxicity of this novel formulation. These studies indicate the potential therapeutic benefits to GBM patients via selective targeting using the rHDL-AMN formulation.

Engineered rHDL Nanoparticles as a Suitable Platform for Theranostic Applications.

Reconstituted high-density lipoproteins (rHDLs) can transport and specifically release drugs and imaging agents, mediated by the Scavenger Receptor Type B1 (SR-B1) present in a wide variety of tumor cells, providing convenient platforms for developing theranostic systems. Usually, phospholipids or Apo-A1 lipoproteins on the particle surfaces are the motifs used to conjugate molecules for the multifunctional purposes of the rHDL nanoparticles. Cholesterol has been less addressed as a region to bind molecules or functional groups to the rHDL surface. To maximize the efficacy and improve the radiolabeling of rHDL theranostic systems, we synthesized compounds with bifunctional agents covalently linked to cholesterol. This strategy means that the radionuclide was bound to the surface, while the therapeutic agent was encapsulated in the lipophilic core. In this research, HYNIC-S-(CH2)3-S-Cholesterol and DOTA-benzene-p-SC-NH-(CH2)2-NH-Cholesterol derivatives were synthesized to prepare nanoparticles (NPs) of HYNIC-rHDL and DOTA-rHDL, which can subsequently be linked to radionuclides for SPECT/PET imaging or targeted radiotherapy. HYNIC is used to complexing 99mTc and DOTA for labeling molecules with 111, 113mIn, 67, 68Ga, 177Lu, 161Tb, 225Ac, and 64Cu, among others. In vitro studies showed that the NPs of HYNIC-rHDL and DOTA-rHDL maintain specific recognition by SR-B1 and the ability to internalize and release, in the cytosol of cancer cells, the molecules carried in their core. The biodistribution in mice showed a similar behavior between rHDL (without surface modification) and HYNIC-rHDL, while DOTA-rHDL exhibited a different biodistribution pattern due to the significant reduction in the lipophilicity of the modified cholesterol molecule. Both systems demonstrated characteristics for the development of suitable theranostic platforms for personalized cancer treatment.

225Ac-rHDL Nanoparticles: A Potential Agent for Targeted Alpha-Particle Therapy of Tumors Overexpressing SR-BI Proteins.

Actinium-225 and other alpha-particle-emitting radionuclides have shown high potential for cancer treatment. Reconstituted high-density lipoproteins (rHDL) specifically recognize the scavenger receptor B type I (SR-BI) overexpressed in several types of cancer cells. Furthermore, after rHDL-SR-BI recognition, the rHDL content is injected into the cell cytoplasm. This research aimed to prepare a targeted 225Ac-delivering nanosystem by encapsulating the radionuclide into rHDL nanoparticles. The synthesis of rHDL was performed in two steps using the microfluidic synthesis method for the subsequent encapsulation of 225Ac, previously complexed to a lipophilic molecule (225Ac-DOTA-benzene-p-SCN, CLog P = 3.42). The nanosystem (13 nm particle size) showed a radiochemical purity higher than 99% and stability in human serum. In vitro studies in HEP-G2 and PC-3 cancer cells (SR-BI positive) demonstrated that 225Ac was successfully internalized into the cytoplasm of cells, delivering high radiation doses to cell nuclei (107 Gy to PC-3 and 161 Gy to HEP-G2 nuclei at 24 h), resulting in a significant decrease in cell viability down to 3.22 ± 0.72% for the PC-3 and to 1.79 ± 0.23% for HEP-G2 at 192 h after 225Ac-rHDL treatment. After intratumoral 225Ac-rHDL administration in mice bearing HEP-G2 tumors, the biokinetic profile showed significant retention of radioactivity in the tumor masses (90.16 ± 2.52% of the injected activity), which generated ablative radiation doses (649 Gy/MBq). The results demonstrated adequate properties of rHDL as a stable carrier for selective deposition of 225Ac within cancer cells overexpressing SR-BI. The results obtained in this research justify further preclinical studies, designed to evaluate the therapeutic efficacy of the 225Ac-rHDL system for targeted alpha-particle therapy of tumors that overexpress the SR-BI receptor.

Targeted photodynamic therapy using reconstituted high-density lipoproteins as rhodamine transporters

Reconstituted high-density lipoprotein (rHDL) nanoparticles are excellent transporters of molecules and very useful for targeted therapy as they specifically recognize the scavenger receptor, class B1 (SR-B1) that is present on the surface of a wide range of tumor cells. However, they have rarely been employed to transport photosensitizers (PS) for photodynamic therapy (PDT). Rhodamine (R) compounds have been dismissed as useful PSs for PDT due to their low 1O2 production, excitation wavelengths with little tissue penetration, and poor selectivity for tumor cells. It was recently demonstrated that when irradiating at 532 nm or with Cerenkov radiation (CR) from a β-emitting radionuclide, R123, R6G, and RB undergo electron transfer reactions (type I reaction) with folic acid. R6G also produces type I reactions with O2. In this work, the photodynamic effects of the rHDL-R system were evaluated in vitro. rHDL nanoparticles loaded with R123, R6G, and RB were synthesized, and the PS was internalized into T47D tumor cells. When cells were irradiated with a 532-nm laser in the presence of an rHDL-R systems, a cytotoxic photodynamic effect was obtained in the order R6G > R123 > RB. In the presence of CR from a 177Lu source, cytotoxicity showed the order R6G > RB > R123. The higher cytotoxicity induced by R6G in both cases corresponds to higher cellular internalization and larger production of type I and II reactions. Thus, in this work, it is proposed that rHDL-R/177Lu system can be applied in theragnostics as a multimodal radiotherapy-PDT-imaging system (imaging by SPECT or Cerenkov) and in hypoxic solid tumors in which external radiation is not effective and 177Lu-CR acts as light source.

Abstract 300: An improved strategy for delivering the mesoionic compound MIH 2.4Bl utilizing reconstituted high density nanoparticles (rHDL) in treating breast cancer

Abstract Based on data from the World Health Organization, breast cancer is the most common type of cancer among women, accounting for about 15% of all cancer-related deaths. Thus, new treatment options are urgently needed to decrease this mortality rate. In recent years, mesoionic compounds have shown promising potential as anti-cancer agents due to their unique structure and reaction properties. We recently reported that a 1,3-thiazolium-5-thiolate mesoionic compound (MIH 2.4Bl) inhibited oxidative phosphorylation in the MCF-7 breast cancer cell line compared to normal human mammary epithelial cells. Furthermore, MIH 2.4Bl induced cytotoxicity by activating autography-related proteins (Beclin-1 and ATG5) and cell cycle arrest at the G2/M phase. Based on our previous findings, MIH 2.4BI is a promising candidate for treating breast cancer. However, a major challenge facing cancer therapeutics is tumor delivery in vivo for the selective destruction of malignant cells while sparing normal cells to preserve tissue integrity. The development and use of drug delivery systems is a recognized approach to improve the efficacy of chemotherapy agents. Nonetheless, drug delivery systems have been largely unexplored in the context of mesoionic compounds. Lipoproteins are ideal for carrying transporting lipophilic anti-cancer drugs and imaging agents as they circulate in the bloodstream for an extended period. In addition, the hydrophobic core of lipoprotein particles allows the incorporation of lipophilic components (including a number of anti-cancer agents). Reconstituted high-density lipoprotein (rHDL) mimics the structure and function of endogenous (i.e., human plasma) HDL and thus presents a potentially markedly improved therapeutic strategy for cancer drug delivery. Previous studies from our group have shown that a stable reconstituted synthetic rHDL-drug complex could be prepared by combining paclitaxel and other chemotherapy drugs using the natural lipid and protein components of circulating HDL via a novel procedure. In this preliminary work, we present an improved strategy of using a newly developed formulation of MIH 2.4BI compound with rHDL nanoparticles as the delivery agent. Also, physico-chemical characterization of the nanoparticles and cytotoxicity analyses using a panel of breast cancer cell lines were performed. These studies support the potential therapeutic use of MIH 2.4Bl in treating breast cancer. (D. Debnath and R.M. Petty contributed equally to this work) Citation Format: Dipti Debnath, R. Max Petty, Nirupama Sabnis, Jinmin Zhang, Andras G. Lacko, Helivaldo Diógenes Souza, Petrônio Filgueiras Filho, J. Michael Mathis, Rafal Fudala. An improved strategy for delivering the mesoionic compound MIH 2.4Bl utilizing reconstituted high density nanoparticles (rHDL) in treating breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 300.

Reconstituted high density lipoprotein (rHDL), a versatile drug delivery nanoplatform for tumor targeted therapy.

rHDL is a synthesized drug delivery nanoplatform exhibiting excellent biocompatibility, which possesses most of the advantages of HDL. rHDL shows almost no toxicity and can be degraded to non-toxic substances in vivo. The severe limitation of the application of various antitumor agents is mainly due to their low bioavailability, high toxicity, poor stability, etc. Favorably, antitumor drug-loaded rHDL nanoparticles (NPs), which are known as an important drug delivery system (DDS), help to change the situation a lot. This DDS shows an outstanding active-targeting ability towards tumor cells and improves the therapeutic effect during antitumor treatment while overcoming the shortcomings mentioned above. In the following text, we will mainly focus on the various applications of rHDL in tumor targeted therapy by describing the properties, preparation, receptor active-targeting ability and antitumor effects of antineoplastic drug-loaded rHDL NPs.

Roles of Reconstituted High-Density Lipoprotein Nanoparticles in Cardiovascular Disease: A New Paradigm for Drug Discovery.

Epidemiological results revealed that there is an inverse correlation between high-density lipoprotein (HDL) cholesterol levels and risks of atherosclerotic cardiovascular disease (ASCVD). Mounting evidence supports that HDLs are atheroprotective, therefore, many therapeutic approaches have been developed to increase HDL cholesterol (HDL-C) levels. Nevertheless, HDL-raising therapies, such as cholesteryl ester transfer protein (CETP) inhibitors, failed to ameliorate cardiovascular outcomes in clinical trials, thereby casting doubt on the treatment of cardiovascular disease (CVD) by increasing HDL-C levels. Therefore, HDL-targeted interventional studies were shifted to increasing the number of HDL particles capable of promoting ATP-binding cassette transporter A1 (ABCA1)-mediated cholesterol efflux. One such approach was the development of reconstituted HDL (rHDL) particles that promote ABCA1-mediated cholesterol efflux from lipid-enriched macrophages. Here, we explore the manipulation of rHDL nanoparticles as a strategy for the treatment of CVD. In addition, we discuss technological capabilities and the challenge of relating preclinical in vivo mice research to clinical studies. Finally, by drawing lessons from developing rHDL nanoparticles, we also incorporate the viabilities and advantages of the development of a molecular imaging probe with HDL nanoparticles when applied to ASCVD, as well as gaps in technology and knowledge required for putting the HDL-targeted therapeutics into full gear.

Artificial High Density Lipoprotein Nanoparticles in Cardiovascular Research.

Lipoproteins are endogenous nanoparticles which are the major transporter of fats and cholesterol in the human body. They play a key role in the regulatory mechanisms of cardiovascular events. Lipoproteins can be modified and manipulated to act as drug delivery systems or nanocarriers for contrast agents. In particular, high density lipoproteins (HDL), which are the smallest class of lipoproteins, can be synthetically engineered either as nascent HDL nanodiscs or spherical HDL nanoparticles. Reconstituted HDL (rHDL) particles are formed by self-assembly of various lipids and apolipoprotein AI (apo-AI). A variety of substances including drugs, nucleic acids, signal emitting molecules, or dyes can be loaded, making them efficient nanocarriers for therapeutic applications or medical diagnostics. This review provides an overview about synthesis techniques, physicochemical properties of rHDL nanoparticles, and structural determinants for rHDL function. We discuss recent developments utilizing either apo-AI or apo-AI mimetic peptides for the design of pharmaceutical rHDL formulations. Advantages, limitations, challenges, and prospects for clinical translation are evaluated with a special focus on promising strategies for the treatment and diagnosis of atherosclerosis and cardiovascular diseases.

Re‐polarization of tumor‐associated macrophages via reconstituted high‐density lipoprotein nanoparticles

Phenotypic plasticity of macrophages allows them to assume different functional profiles as they are called upon to respond to biological events. For example, the M1 phenotype of macrophage potentiates pro‐inflammatory and anti‐tumoral properties whereas the M2 phenotype is associated with immuno‐regulatory, tissue repair and pro‐tumoral properties. Tumor‐associated macrophages (TAMs) initially present anti‐tumoral behaviors via their “M1” phenotype. Under the stimulation of factors secreted by the malignant tumor, TAMs progressively take on a pro‐tumoral role via polarization to an “M2” phenotype. The M2 phenotype which supports immune‐dampening activities helps sustain tumor proliferation, immune system evasion, angiogenesis, tissue invasion and metastasis. TAMs, thus, make attractive targets for an anti‐cancer immunotherapy strategy. Considering the whole‐body distribution of macrophages, and their critical role in immune response, we propose to pursue the repolarization of M2‐type macrophages in the tumor microenvironment toward an M1 phenotype, utilizing a targeted drug delivery carrier.Lipoproteins are natural transporters of hydrophobic substances in the blood, including lipids, hormones and drugs. Our lab developed a biocompatible reconstituted high‐density lipoprotein (rHDL) nanoparticle with properties highly similar to the native HDL. Dynamic light scattering analysis and transmission electron micrographs have confirmed a sub‐50 nm size for our particles and a spherical shape. In addition to siRNA molecules, hydrophobic drugs such as paclitaxel and valrubicin were successfully encapsulated by the rHDL nanoparticle. Photophysical studies showed that as a carrier, the rHDL holds its cargo at its core. Receptor blocking studies showed that scavenger receptor, class B type 1 (SR‐B1) expressed on the surface of the target cell mediate the intracellular delivery of the nanoparticle's payload by interacting with ApoA1, a major protein component of the nanoparticle. Also, protein expression analysis showed that M2‐type macrophages exhibit higher levels of SR‐B1 compared to M1‐type macrophages. The rHDL nanoparticles can transport hydrophobic small molecule inhibitors or non‐coding RNAs often used in subtype reversal/re‐polarization (M2 to M1) strategies. Most importantly, the SR‐B1 expression profile of M2‐type macrophage indicates that the rHDL is particularly suited for selective targeted delivery of these agents to TAMs.Support or Funding InformationCerenis TherapeuticsThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

99mTc-HYNIC-N-dodecylamide]: a new hydrophobic tracer for labelling reconstituted high-density lipoproteins (rHDL) for radioimaging.

Despite the widespread use of nanotechnology in radio-imaging applications, lipoprotein based delivery systems have received only limited attention so far. These studies involve the synthesis of a novel hydrophobic radio-imaging tracer consisting of a hydrazinonicotinic acid (HYNIC)-N-dodecylamide and 99mTc conjugate that can be encapsulated into rHDL nanoparticles (NPs). These rHDL NPs can selectively target the Scavenger Receptor type B1 (SR-B1) that is overexpressed on most cancer cells due to excess demand for cholesterol for membrane biogenesis and thus can target tumors in vivo. We provide details of the tracer synthesis, characterization of the rHDL/tracer complex, in vitro uptake, stability studies and in vivo application of this new radio-imaging approach.

Targeting CD40-Induced TRAF6 Signaling in Macrophages Reduces Atherosclerosis

BackgroundDisrupting the costimulatory CD40-CD40L dyad reduces atherosclerosis, but can result in immune suppression. The authors recently identified small molecule inhibitors that block the interaction between CD40 and tumor necrosis factor receptor-associated factor (TRAF) 6 (TRAF-STOPs), while leaving CD40-TRAF2/3/5 interactions intact, thereby preserving CD40-mediated immunity. ObjectivesThis study evaluates the potential of TRAF-STOP treatment in atherosclerosis. MethodsThe effects of TRAF-STOPs on atherosclerosis were investigated in apolipoprotein E deficient (Apoe−/−) mice. Recombinant high-density lipoprotein (rHDL) nanoparticles were used to target TRAF-STOPs to macrophages. ResultsTRAF-STOP treatment of young Apoe−/− mice reduced atherosclerosis by reducing CD40 and integrin expression in classical monocytes, thereby hampering monocyte recruitment. When Apoe−/− mice with established atherosclerosis were treated with TRAF-STOPs, plaque progression was halted, and plaques contained an increase in collagen, developed small necrotic cores, and contained only a few immune cells. TRAF-STOP treatment did not impair “classical” immune pathways of CD40, including T-cell proliferation and costimulation, Ig isotype switching, or germinal center formation, but reduced CD40 and β2-integrin expression in inflammatory monocytes. In vitro testing and transcriptional profiling showed that TRAF-STOPs are effective in reducing macrophage migration and activation, which could be attributed to reduced phosphorylation of signaling intermediates of the canonical NF-κB pathway. To target TRAF-STOPs specifically to macrophages, TRAF-STOP 6877002 was incorporated into rHDL nanoparticles. Six weeks of rHDL-6877002 treatment attenuated the initiation of atherosclerosis in Apoe−/− mice. ConclusionsTRAF-STOPs can overcome the current limitations of long-term CD40 inhibition in atherosclerosis and have the potential to become a future therapeutic for atherosclerosis.

SR-B1-targeted nanodelivery of anti-cancer agents: a promising new approach to treat triple-negative breast cancer.

Patients with triple-negative breast cancer (TNBC) have a considerably less favorable prognosis than those with hormone-positive breast cancers. TNBC patients do not respond to current endocrine treatment and have a 5-year survival prognosis of <30%. The research presented here is intended to fill a void toward the much needed development of improved treatment strategies for metastatic TNBC. The overall goal of this research was to evaluate the effectiveness of reconstituted high-density lipoprotein (rHDL) nanoparticles (NPs) as delivery agents for anti-TNBC drugs. Using lapatinib and valrubicin as components of the rHDL/drug complexes resulted in a significantly better performance of the NP-transported drugs compared with their free (unencapsulated) counterparts. The enhancement of the therapeutic effect and the protection of normal cells (cardiomyocytes) achieved via the rHDL NPs were likely due to the overexpression of the high-density lipoprotein (HDL) (scavenger receptor class B type 1 [SR-B1]) receptor by the TNBC cells.

Abstract 224: TRAF-STOP-RHDL-Nanoparticles Reduce Atherosclerosis

Background: Inhibition of the costimulatory CD40-CD40L receptor/ligand dyad drastically reduces atherosclerosis. However, its long-term blockage can result in immune suppression. We recently identified small molecule inhibitors that block the interaction between CD40 and TNF Receptor Associated Factor (TRAF) 6 (TRAF-STOPs), while leaving CD40-TRAF2/3/5 interactions intact, thereby preserving CD40-mediated immunity. We investigated the potential of the TRAF-STOPs to treat atherosclerosis. Results: Treatment of ApoE-/- mice with either TRAF-STOP 6877002 or 6860766 reduced both initial and established atherosclerosis and induced a stable plaque phenotype with increased collagen and VSMC content, decreased lipid core, and a decrease in macrophage number. There were no signs of immune suppression or toxicity. In vitro experiments showed that the TRAF-STOPs reduced inflammation in macrophages, but not in T- or B cells, endothelial cells or vascular smooth muscle cells. Intravital microscopy demonstrated that the TRAF-STOPs reduced monocyte recruitment to the plaque. The CD36-mediated uptake of ox-LDL by macrophages and foam cell formation was also inhibited by TRAF-STOPs. Transcriptomics analysis and Ingenuity pathway analysis of TRAF-STOP-treated bone marrow-derived macrophages revealed that the top ranking canonical pathways for both TRAF-STOPs involved pro-inflammatory immune responses and cholesterol biosynthesis. 6877002 also affected cell cycle regulation. Surface plasmon resonance experiments and mutation studies demonstrated that 6877002 and 6860766 had a different interaction site within the TRAF6 C-domain, which explained the additional effect of 6877002. To target TRAF-STOPs specifically to macrophages, 6877002 was incorporated into rHDL nanoparticles. Flowcytometry and fluorescent microscopy demonstrated accumulation of rHDL-6877002 in plaque macrophages after a single dosis. Six weeks of rHDL-6877002 treatment reduced atherosclerosis in ApoE-/- mice. Conclusions: TRAF-STOP 6877002 and 6860766 can overcome the current limitations of long-term CD40 and CD40L inhibition and nanoparticle-mediated delivery TRAF-STOP to plaque macrophages may become a future therapy for atherosclerosis.

Targeted Biomimetic Nanoparticles for Synergistic Combination Chemotherapy of Paclitaxel and Doxorubicin.

Codelivery of multiple chemotherapeutics has become a versatile strategy in recent cancer treatment, but the antagonistic behavior of combined drugs limited their application. We developed a recombinant high-density lipoprotein (rHDL) nanoparticle for the precise coencapsulation and codelivery of two established drugs and hypothesized that they could act synergistically to improve anticancer efficacy. The coloaded rHDL was formulated by passively incorporating hydrophobic paclitaxel (PTX), and subsequently remotely loading hydrophilic doxorubicin (Dox) into the same nanoparticles. The resultant rHDL system restored targeted delivery function toward cancer cells via scavenger receptor class B (SR-BI), as confirmed by in vitro confocal imaging and flow cytometry. These coloaded rHDL nanoparticles were remarkably effective in increasing the ratiometric accumulation of drugs in cancer cells and enhancing antitumor response at synergistic drug ratios. In particular, they exhibited more efficacious anticancer effects in an in vitro cytotoxicity evaluation and in a xenograft tumor model of hepatoma compared with free drug cocktail solutions. These results confirm that the coloaded rHDL nanoparticles are promising candidates for the synergistic delivery of drugs with diverse physicochemical properties in cancer treatment integrating efficiency and safety considerations.

Reconstituted high density lipoprotein mediated targeted co-delivery of HZ08 and paclitaxel enhances the efficacy of paclitaxel in multidrug-resistant MCF-7 breast cancer cells

In the past decades, reconstituted high density lipoprotein (rHDL) has been successfully developed as a drug carrier since the enhanced HDL-lipids uptake is demonstrated in several human cancers. In this paper, rHDL, for the first time, was utilized to co-encapsulate two hydrophobic drugs: an anticancer drug, paclitaxel (PTX), and a new reversal agent for P-gp (P-glycoprotein)-mediated multidrug resistance (MDR) of cancer, N-cyano-1-[(3,4-dimethoxyphenyl)methyl]-3,4-dihydro-6,7-dimethoxy-N′-octyl-2(1H)-isoquinoline-carboximidamide (HZ08). We proposed this drug co-delivery strategy to reverse PTX resistance. The study aimed to develop a biomimetic nanovector, reconstituted high density lipoprotein (rHDL), mediating targeted PTX-HZ08 delivery for cancer therapy. Using sodium cholate dialysis method, we successfully formulated dual-agent co-delivering rHDL nanoparticles (PTX-HZ08-rHDL NPs) with a typical spherical morphology, well-distributed size (~100nm), high drug encapsulation efficiency (approximately 90%), sustained drug release properties and exceptional stability even after storage for 1month or incubation in 10% fetal bovine serum (FBS) DMEM for up to 2days. Results demonstrated that PTX-HZ08-rHDL NPs significantly enhanced anticancer efficacy in vitro, including higher cytotoxicity and better ability to induce cell apoptosis against both PTX-sensitive and -resistant MCF-7 human breast cancer cell lines (MCF-7 and MCF-7/PTX cells). Mechanism studies demonstrated that these improvements could be correlated with increased cellular uptake of PTX mediated by scavenger receptor class B type I (SR-BI) as well as prolonged intracellular retention of PTX due to the HZ08 mediated drug-efflux inhibition. In addition, in vivo investigation showed that the PTX-HZ08-rHDL NPs were substantially safer, have higher tumor-targeted capacity and have stronger antitumor activity than the corresponding dosage of paclitaxel injection. These findings suggested that rHDL NPs could be an ideal tumor-targeted nanovector for simultaneous transfer of insoluble anticancer drug and drug resistance reversal agents. The PTX-HZ08-rHDL NPs co-delivery system might be a new promising strategy to overcome tumor drug resistance.

Novel nanoparticulate drug delivery systems.

Multifunctional GM1–modified lipoprotein-like nanoparticles for the therapy of Alzheimer’s Disease Evaluation of: Huang M, Hu M, Song Q et al. GM1–modified lipoproteinlike nanoparticle: multifunctional nanoplatform for the combination therapy of Alzheimer’s disease. ACS Nano. 9(11), 10801–10816 (2015). Alzheimer’s disease (AD) is the most common neurodegenerative disorder, affecting about 11% of people aged 65 years and older in the USA alone. According to the estimates, this number may nearly triple by 2050 [1] resulting in an increased health and economic burden, which urgently calls for more effective therapies. The molecular basis for the formation of the extracellular amyloid plaques found in the brain of AD patients involves the strong neurotoxic effects of soluble amyloid-β (Aβ) [2]. In their recent paper, Huang et al. have developed a flexible multifunctional noninvasive drug delivery system for accelerated Aβ clearance, protection of neurons and inhibition of other pathological cascades induced by Aβ accumulation. Reconstituted high-density lipoprotein (rHDL) and monosialotetrahexosylganglioside (GM1)-rHDL nanoparticles were prepared by self-assembly from lipid-free apoE3 and 1,2–dimyristoyl-sn-glycero–3–phosphocholine (DMPC) liposomes or GM1–DMPC liposomes, respectively [3]. Surface plasmon resonance analysis showed a very high affinity of GM1–rHDL to monomeric and oligomeric Aβ 1–42 , comparable with anti-Aβ antibody binding. Following the extensive physicochemical analyses, in vivo experiments demonstrated a high level of GM1–rHDL in the brain after intranasal application in mice, confirming the feasibility of noninvasive administration of these nanoparticles. Subsequent in vitro and in vivo experiments revealed a strong improvement of different Aβ clearing pathways in the presence of GM1– rHDL as compared with rHDL. In primary microglia, GM1–rHDL facilitated the cellular uptake and intracellular degradation of Aβ 1–42 . Increased Aβ degradation and an accelerated Aβ brain-to-blood efflux after injection of I-labeled Aβ 1–42 oligomers into the unilateral hippocampus was also achieved in vivo with intranasally administered GM1–rHDL. Beside increased Aβ levels, AD is characterized by loss of neurons and synapses leading to memory loss, cognitive deficits and ultimately to death. Consequently, a successful therapy should combine strategies for Aβ clearance and neuroprotection. To verify the drugdelivery capacity of GM1–rHDL, the authors selected a neuroprotective octapeptide, NAP, as a model drug for AD. The resulting αNAP-GM1–rHDL particles increased the viability of Aβ 1–42 oligomer-treated primary neurons and reversed neuronal dysfunction by increasing the neurite length and branch point counts. Additionally, αNAP-GM1–rHDL Novel nanoparticulate drug delivery systems

Photophysical characterization of anticancer drug valrubicin in rHDL nanoparticles and its use as an imaging agent

Nanoparticles are target-specific drug delivery agents that are increasingly used in cancer therapy to enhance bioavailability and to reduce off target toxicity of anti-cancer agents. Valrubicin is an anti-cancer drug, currently approved only for vesicular bladder cancer treatment because of its poor water solubility. On the other hand, valrubicin carrying reconstituted high density lipoprotein (rHDL) nanoparticles appear ideally suited for extended applications, including systemic cancer chemotherapy. We determined selected fluorescence properties of the free (unencapsulated) drug vs. valrubicin incorporated into rHDL nanoparticles. We have found that upon encapsulation into rHDL nanoparticles the quantum yield of valrubicin fluorescence increased six fold while its fluorescence lifetime increased about 2 fold. Accordingly, these and potassium iodide (KI) quenching data suggest that upon incorporation, valrubicin is localized deep in the interior of the nanoparticle, inside the lipid matrix. Fluorescence anisotropy of the rHDL valrubicin nanoparticles was also found to be high along with extended rotational correlation time. The fluorescence of valrubicin could also be utilized to assess its distribution upon delivery to prostate cancer (PC3) cells. Overall the fluorescence properties of the rHDL: valrubicin complex reveal valuable novel characteristics of this drug delivery vehicle that may be particularly applicable when used in systemic (intravenous) therapy.

Abstract B54: SR-B1 directed nanoparticles in targeted therapy for the treatment of metastatic triple-negative breast cancer

Abstract This study endeavors to fill a void in the treatment of metastatic triple negative breast cancer (TNBC) with the use of scavenger receptor class B type 1 (SR-B1) targeted reconstituted high-density lipoprotein (rHDL) nanoparticles. Though new therapies are being evaluated in clinical trials, TNBC remains an incurable disease. Accordingly, the 5-year survival rate for women with metastatic TNBC is less than 30%. The overall goal of this study is to evaluate the efficacy of Lapatinib (an EGFR inhibitor) and Valrubicin (a topoisomerase II inhibitor) encapsulated rHDL nanoparticles in the treatment of metastatic TNBC. Selective uptake of anticancer agents delivered by rHDL nanoparticles via the SR-B1 is being evaluated using H3 cholesterol ester labeled rHDL nanoparticles in the presence and absence of a chemical inhibitor of SR-B1. Anti-proliferative effects of Lapatinib and Valrubicin encapsulated nanoparticles were evaluated using CCK-8 kits. The findings from these studies revealed that the rHDL encapsulated forms of Lapatinib and Valrubicin had enhanced efficacy when used in combination than the free drugs. In particular, rHDL encapsulated Lapatinib had a 55% increase in efficacy in MDA-MB-231 cell line over the un-encapsulated form as a single agent. The ultimate goal of these studies is to assess the impact of rHDL encapsulated Lapatinib and Valrubicin, alone or in combination against TNBC. One of the major barriers to successful cancer chemotherapy is the development of multidrug resistance (MDR) by malignant tumors. rHDL nanoparticles provide a cytosolic drug delivery mechanism for malignant cells and will likely help to overcome drug resistance by TNBC tumors. In addition, the tumor selective delivery of the drug payload via the rHDL nanoparticles is anticipated to reduce or eliminate off target toxicity to normal tissues upon clinical application. Citation Format: Rebecca Johnson, Andras Lacko. SR-B1 directed nanoparticles in targeted therapy for the treatment of metastatic triple-negative breast cancer. [abstract]. In: Proceedings of the Seventh AACR Conference on The Science of Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; Nov 9-12, 2014; San Antonio, TX. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2015;24(10 Suppl):Abstract nr B54.

PET Imaging of Tumor-Associated Macrophages with 89Zr-Labeled High-Density Lipoprotein Nanoparticles.

Tumor-associated macrophages (TAMs) are increasingly investigated in cancer immunology and are considered a promising target for better and tailored treatment of malignant growth. Although TAMs also have high diagnostic and prognostic value, TAM imaging still remains largely unexplored. Here, we describe the development of reconstituted high-density lipoprotein (rHDL)-facilitated TAM PET imaging in a breast cancer model. Radiolabeled rHDL nanoparticles incorporating the long-lived positron-emitting nuclide (89)Zr were developed using 2 different approaches. The nanoparticles were composed of phospholipids and apolipoprotein A-I (apoA-I) in a 2.5:1 weight ratio. (89)Zr was complexed with deferoxamine (also known as desferrioxamine B, desferoxamine B), conjugated either to a phospholipid or to apoA-I to generate (89)Zr-PL-HDL and (89)Zr-AI-HDL, respectively. In vivo evaluation was performed in an orthotopic mouse model of breast cancer and included pharmacokinetic analysis, biodistribution studies, and PET imaging. Ex vivo histologic analysis of tumor tissues to assess regional distribution of (89)Zr radioactivity was also performed. Fluorescent analogs of the radiolabeled agents were used to determine cell-targeting specificity using flow cytometry. The phospholipid- and apoA-I-labeled rHDL were produced at 79% ± 13% (n = 6) and 94% ± 6% (n = 6) radiochemical yield, respectively, with excellent radiochemical purity (>99%). Intravenous administration of both probes resulted in high tumor radioactivity accumulation (16.5 ± 2.8 and 8.6 ± 1.3 percentage injected dose per gram for apoA-I- and phospholipid-labeled rHDL, respectively) at 24 h after injection. Histologic analysis showed good colocalization of radioactivity with TAM-rich areas in tumor sections. Flow cytometry revealed high specificity of rHDL for TAMs, which had the highest uptake per cell (6.8-fold higher than tumor cells for both DiO@Zr-PL-HDL and DiO@Zr-AI-HDL) and accounted for 40.7% and 39.5% of the total cellular DiO@Zr-PL-HDL and DiO@Zr-AI-HDL in tumors, respectively. We have developed (89)Zr-labeled TAM imaging agents based on the natural nanoparticle rHDL. In an orthotopic mouse model of breast cancer, we have demonstrated their specificity for macrophages, a result that was corroborated by flow cytometry. Quantitative macrophage PET imaging with our (89)Zr-rHDL imaging agents could be valuable for noninvasive monitoring of TAM immunology and targeted treatment.