An in situ depot for the sustained release of a TLR7/8 agonist in combination with a TGFβ inhibitor promotes anti-tumor immune responses.

Cancer curing immune responses against heterogeneous solid cancers require that a coordinated immune activation is initiated in the antigen avid but immunosuppressive tumor microenvironment (TME). The plastic TME, and the poor systemic tolerability of immune activating drugs are, however, fundamental barriers to generating curative anticancer immune responses. Here, we introduce the CarboCell technology to overcome these barriers by forming an intratumoral sustained drug release depot that provides high payloads of immune stimulatory drugs selectively within the TME.

HER2-targeted, enzyme-activated liposomes show superior in vivo efficacy in an ovarian cancer model.

Liposomes carrying chemotherapeutic drugs can accumulate passively in solid tumors at high levels. However, additional targeting of the liposomes towards e.g.

Active Transport and Ocular Distribution of Intravitreally Injected Liposomes.

Purpose: Drug delivery to the retina remains a challenge due to ocular barriers and fast clearing mechanisms. Nanocarrier drug delivery systems (NDDSs) hold the promise of prolonging intraocular retention times and increasing drug concentrations in the retina.

Methods: Anionic and cationic PEGylated liposomes, loaded with oxaliplatin (OxPt) to be used as trace element, were prepared from dry lipid powders.

Photothermal Therapy as Adjuvant to Surgery in an Orthotopic Mouse Model of Human Fibrosarcoma.

Surgery is still the first-line treatment for multiple solid cancers. However, recurrence is a common issue, especially when dealing with aggressive tumors or tumors that are difficult to completely remove due to their location. Getting clear surgical margins can be challenging, but treatment strategies combining surgery with other anti-cancer therapies can potentially improve the outcome.

Effective Intratumoral Retention of [ Pd]AuPd Alloy Nanoparticles Embedded in Gel-Forming Liquids Paves the Way for New Nanobrachytherapy.

Local application of radioactive sources as brachytherapy is well established in oncology. This treatment is highly invasive however, due to the insertion of millimeter sized metal seeds. The authors report the development of a new concept for brachytherapy, based on gold-palladium (AuPd) alloy nanoparticles, intrinsically radiolabeled with Pd.

Elucidating the anomalous membrane permeability of Ag(I), Cu(II), Zn(II) and Au(III) towards new nanoreactor strategies for synthesizing metal nanoparticles.

The main structural element defining the cell is the lipid membrane, which is an integral part of regulating the fluxes of ion and nutrition molecules in and out of the cell. Surprisingly, copper ions were found to have anomalous membrane permeability. This led us to consider a broader spectrum of cations and further a new approach for using liposomes as nanoreactors for synthesis of metal and metal alloy nanoparticles.

Preclinical evaluation of cationic DOTA-triarginine-lipid conjugates for theranostic liquid brachytherapy.

Liquid brachytherapy is an emerging technology for internal radiation therapy where liquids containing radionuclides are administered directly into solid tumors. These technologies are less invasive than conventional brachytherapy, and can potentially improve the dose coverage and homogeneity of the radioactivity distribution within the tumor. For this purpose, we have developed a novel cationic micelle system for delivery of a range of radionuclides.

Monitoring cell endocytosis of liposomes by real-time electrical impedance spectroscopy.

Evaluation and understanding the effect of drug delivery in in vitro systems is fundamental in drug discovery. We present an assay based on real-time electrical impedance spectroscopy (EIS) measurements that can be used to follow the internalisation and cytotoxic effect of a matrix metalloproteinase (MMP)-sensitive liposome formulation loaded with oxaliplatin (OxPt) on colorectal cancer cells. The EIS response identified two different cellular processes: (i) a negative peak in the cell index (CI) within the first 5 h, due to onset of liposome endocytosis, followed by (ii) a subsequent CI increase, due to the reattachment of cells until the onset of cytotoxicity with a decrease in CI.

Modulating the antibody density changes the uptake and transport at the blood-brain barrier of both transferrin receptor-targeted gold nanoparticles and liposomal cargo.

Transport of the majority of therapeutic molecules to the brain is precluded by the presence of the blood-brain barrier (BBB) rendering efficient treatment of many neurological disorders impossible. This BBB, nonetheless, may be circumvented by targeting receptors and transport proteins expressed on the luminal surface of the brain capillary endothelial cells (BCECs). The transferrin receptor (TfR) has remained a popular target since its original description for this purpose, although clinical progression of TfR-targeted drug constructs or nanomedicines remains unsuccessful.

Theranostic Imaging May Vaccinate against the Therapeutic Benefit of Long Circulating PEGylated Liposomes and Change Cargo Pharmacokinetics.

The enhanced permeability and retention (EPR) effect increases tumor accumulation of liposomal chemotherapy and should, in theory, increase anticancer effects and lower toxicity. Unfortunately, liposomal chemotherapy has generally not met the expected potential, perhaps because the EPR effect is not ubiquitous. PET imaging using radiolabeled liposomes can identify cancers positive for the EPR effect.

Multifarious Biologic Loaded Liposomes that Stimulate the Mammalian Target of Rapamycin Signaling Pathway Show Retina Neuroprotection after Retina Damage.

A common event in optic neuropathies is the loss of axons and death of retinal ganglion cells (RGCs) resulting in irreversible blindness. Mammalian target of rapamycin (mTOR) signaling pathway agonists have been shown to foster axon regeneration and RGC survival in animal models of optic nerve damage. However, many challenges remain in developing therapies that exploit cell growth and tissue remodeling including (i) activating/inhibiting cell pathways synergistically, (ii) avoiding tumorigenesis, and (iii) ensuring appropriate physiological tissue function.

Antibody affinity and valency impact brain uptake of transferrin receptor-targeted gold nanoparticles.

The ability to treat invalidating neurological diseases is impeded by the presence of the blood-brain barrier (BBB), which inhibits the transport of most blood-borne substances into the brain parenchyma. Targeting the transferrin receptor (TfR) on the surface of brain capillaries has been a popular strategy to give a preferential accumulation of drugs or nanomedicines, but several aspects of this targeting strategy remain elusive. Here we report that TfR-targeted gold nanoparticles (AuNPs) can accumulate in brain capillaries and further transport across the BBB to enter the brain parenchyma.

Endothelial Protein C-Targeting Liposomes Show Enhanced Uptake and Improved Therapeutic Efficacy in Human Retinal Endothelial Cells.

Purpose: To determine whether human retinal endothelial cells (HRECs) express the endothelial cell protein C receptor (EPCR) and to realize its potential as a targeting moiety by developing novel single and dual corticosteroid-loaded functionalized liposomes that exhibit both enhanced uptake by HRECs and superior biologic activity compared to nontargeting liposomes and free drug.

Methods: EPCR expression of HRECs was investigated through flow cytometry and Western blot assays. EPCR-targeting liposomes were developed by functionalizing EPCR-specific antibodies onto liposomes, and the uptake of liposomes was assessed with flow cytometry and confocal laser scanning microscopy.

Targeting transferrin receptors at the blood-brain barrier improves the uptake of immunoliposomes and subsequent cargo transport into the brain parenchyma.

Drug delivery to the brain is hampered by the presence of the blood-brain barrier, which excludes most molecules from freely diffusing into the brain, and tightly regulates the active transport mechanisms that ensure sufficient delivery of nutrients to the brain parenchyma. Harnessing the possibility of delivering neuroactive drugs by way of receptors already present on the brain endothelium has been of interest for many years. The transferrin receptor is of special interest since its expression is limited to the endothelium of the brain as opposed to peripheral endothelium.

Revisiting the use of sPLA-sensitive liposomes in cancer therapy.

The first developed secretory phospholipase A (sPLA) sensitive liposomal cisplatin formulation (LiPlaCis®) is currently undergoing clinical evaluation. In the present study we revisit and evaluate critical preclinical parameters important for the therapeutic potential and safety of platinum drugs, here oxaliplatin (L-OHP), formulated in sPLA sensitive liposomes. We show the mole percentage of negatively charged phospholipid needed to obtain enzyme-sensitivity for saturated systems is ≥25% for 16-carbon chain lipid membranes, and >40% for 18-chain lipid membranes, which was surprising as 25% is used clinically in LiPlaCis®.

18F-FDG PET/CT-based early treatment response evaluation of nanoparticle-assisted photothermal cancer therapy.

Within the field of nanoparticle-assisted photothermal cancer therapy, focus has mostly been on developing novel heat-generating nanoparticles with the right optical and dimensional properties. Comparison and evaluation of their performance in tumor-bearing animals are commonly assessed by changes in tumor volume; however, this is usually a late-occurring event. This study implements 2-deoxy-2-[F-18]fluoro-D-glucose positron emission tomography imaging to perform early evaluation of the treatment outcome of photothermal therapy.

Multiplexed Dosing Assays by Digitally Definable Hydrogel Volumes.

Stable and low-cost multiplexed drug sensitivity assays using small volumes of cells or tissue are in demand for personalized medicine, including patient-specific combination chemotherapy. Spatially defined projected light photopolymerization of hydrogels with embedded active compounds is introduced as a flexible and cost-efficient method for producing multiplexed dosing assays. The high spatial resolution of light projector technology defines multiple compound doses by the volume of individual compound-embedded hydrogel segments.

Impedimetric toxicity assay in microfluidics using free and liposome-encapsulated anticancer drugs.

In this work, we have developed a microfluidic cytotoxicity assay for a cell culture and detection platform, which enables both fluid handling and electrochemical/optical detection. The cytotoxic effect of anticancer drugs doxorubicin (DOX), oxaliplatin (OX) as well as OX-loaded liposomes, developed for targeted drug delivery, was evaluated using real-time impedance monitoring. The time-dependent effect of DOX on HeLa cells was monitored and found to have a delayed onset of cytotoxicity in microfluidics compared with static culture conditions based on data obtained in our previous study.

Synthesis of tocopheryl succinate phospholipid conjugates and monitoring of phospholipase A₂ activity.

Tocopheryl succinates (TOSs) are, in contrast to tocopherols, highly cytotoxic against many cancer cells. In this study the enzyme activity of secretory phospholipase A(2) towards various succinate-phospholipid conjugates has been investigated. The synthesis of six novel phospholipids is described, including two TOS phospholipids conjugates.

Mechanistic study of the sPLA2-mediated hydrolysis of a thio-ester pro anticancer ether lipid.

Secretory phospholipase A(2) (sPLA(2)) is an interesting enzyme for triggered liposomal drug delivery to tumor tissue due the overexpression of sPLA(2) in cancerous tissue. A drug delivery system based on the triggered release of therapeutics from sPLA(2)-sensitive liposomes constituted of pro anticancer ether lipids, which become cytotoxic upon sPLA(2)-catalyzed hydrolysis has previously been established. To optimize the hydrolysis rate of the lipids and thereby optimizing the release profile of the drugs from the liposomes, we have synthesized a thio-ester pro anticancer ether lipid.

Synthesis and biophysical characterization of chlorambucil anticancer ether lipid prodrugs.

The synthesis and biophysical characterization of four prodrug ether phospholipid conjugates are described. The lipids are prepared from the anticancer drug chlorambucil and have C16 and C18 ether chains with phosphatidylcholine or phosphatidylglycerol headgroups. All four prodrugs have the ability to form unilamellar liposomes (86-125 nm) and are hydrolyzed by phospholipase A(2), resulting in chlorambucil release.

Phosphorylation of SDT repeats in the MDC1 N terminus triggers retention of NBS1 at the DNA damage-modified chromatin.

DNA double-strand breaks (DSBs) trigger accumulation of the MRE11-RAD50-Nijmegen breakage syndrome 1 (NBS1 [MRN]) complex, whose retention on the DSB-flanking chromatin facilitates survival. Chromatin retention of MRN requires the MDC1 adaptor protein, but the mechanism behind the MRN-MDC1 interaction is unknown. We show that the NBS1 subunit of MRN interacts with the MDC1 N terminus enriched in Ser-Asp-Thr (SDT) repeats.

RNF8 ubiquitylates histones at DNA double-strand breaks and promotes assembly of repair proteins.

Accumulation of repair proteins on damaged chromosomes is required to restore genomic integrity. However, the mechanisms of protein retention at the most destructive chromosomal lesions, the DNA double-strand breaks (DSBs), are poorly understood. We show that RNF8, a RING-finger ubiquitin ligase, rapidly assembles at DSBs via interaction of its FHA domain with the phosphorylated adaptor protein MDC1.

Regulation of the Rab5 GTPase-activating protein RN-tre by the dual specificity phosphatase Cdc14A in human cells.

The Cdc14 family of dual specificity phosphatases regulates key mitotic events in the eukaryotic cell cycle. Although extensively characterized in yeast, little is known about the function of mammalian Cdc14 family members. Here we report a genetic substrate-trapping system designed to identify substrates of the human Cdc14A (hCdc14A) phosphatase.

Spatial organization of the mammalian genome surveillance machinery in response to DNA strand breaks.

We show that DNA double-strand breaks (DSBs) induce complex subcompartmentalization of genome surveillance regulators. Chromatin marked by gamma-H2AX is occupied by ataxia telangiectasia-mutated (ATM) kinase, Mdc1, and 53BP1. In contrast, repair factors (Rad51, Rad52, BRCA2, and FANCD2), ATM and Rad-3-related (ATR) cascade (ATR, ATR interacting protein, and replication protein A), and the DNA clamp (Rad17 and -9) accumulate in subchromatin microcompartments delineated by single-stranded DNA (ssDNA).