Lipid-based nanosystems: the next generation of cancer immune therapy.

Immunotherapy has become an important part of the oncotherapy arsenal. Its applicability in various cancer types is impressive, as well as its use of endogenous mechanisms to achieve desired ends. However, off-target or on-target-off-tumor toxicity, limited activity, lack of control in combination treatments and, especially for solid tumors, low local accumulation, have collectively limited clinical use thereof.

Erratum: Acute cellular and vascular responses to photodynamic therapy using EGFR-targeted nanobody-photosensitizer conjugates studied with intravital optical imaging and magnetic resonance imaging: Erratum.

[This corrects the article DOI: 10.7150/thno.37949.

An In Vivo Model to Study Cell Migration in XYZ-T Dimension Followed by Whole-Mount Re-evaluation.

Cell migration is a very dynamic process involving several chemical as well as biological interactions with other cells and the environment. Several models exist to study cell migration ranging from simple 2D in vitro cultures to more demanding 3D multicellular assays, to complex evaluation in animals. High-resolution 4D (XYZ, spatial + T, time dimension) intravital imaging using transgenic animals with a fluorescent label in cells of interest is a powerful tool to study cell migration in the correct environment.

Liposomal Drug Delivery Systems for Cancer Therapy: The Rotterdam Experience.

At the Nanomedicine Innovation Center (NICE) at the Erasmus MC in Rotterdam, we have approached the treatment of cancer by starting with a vision of first establishing a platform that enables us to overcome the low levels of drugs delivered to tumors and the issue of dose-limiting toxicity. Showing that a reduction of the volume of distribution, and a lowering of toxicity and side-effects, accompanied by augmented intratumoral drug delivery, could change outcomes in patients, paved the way to target, not only localized disease, but also systemic and metastasized cancers. In particular, the detailed studies with intravital microscopy we performed at NICE provided us with the necessary insights and affected to a large extent our program on liposome-based cancer therapy.

Assessment of the In Vivo Response to Nanobody-Targeted PDT Through Intravital Microscopy.

Methods that allow real-time, longitudinal, intravital detection of the fluorescence distribution and the cellular and vascular responses within tumor and normal tissue are important tools to obtain valuable information when investigating new photosensitizers and photodynamic therapy (PDT) responses. Intravital confocal microscopy using the dorsal skinfold chamber model gives the opportunity to visualize and determine the distribution of photosensitizers within tumor and normal tissue. Next to that, it also allows the visualization of the effect of treatment with respect to changes in vascular diameter and blood flow, vascular leakage, and tissue necrosis, in the first days post-illumination.

Preclinical Studies in Small Animals for Advanced Drug Delivery Using Hyperthermia and Intravital Microscopy.

This paper presents three devices suitable for the preclinical application of hyperthermia via the simultaneous high-resolution imaging of intratumoral events. (Pre)clinical studies have confirmed that the tumor micro-environment is sensitive to the application of local mild hyperthermia. Therefore, heating is a promising adjuvant to aid the efficacy of radiotherapy or chemotherapy.

An adapted dorsal skinfold model used for 4D intravital followed by whole-mount imaging to reveal endothelial cell-pericyte association.

Endothelial cells and pericytes are highly dynamic vascular cells and several subtypes, based on their spatiotemporal dynamics or molecular expression, are believed to exist. The interaction between endothelial cells and pericytes is of importance in many aspects ranging from basic development to diseases like cancer. Identification of spatiotemporal dynamics is particularly interesting and methods to studies these are in demand.

Drug transport kinetics of intravascular triggered drug delivery systems.

Intravascular triggered drug delivery systems (IV-DDS) for local drug delivery include various stimuli-responsive nanoparticles that release the associated agent in response to internal (e.g., pH, enzymes) or external stimuli (e.

Externally triggered smart drug delivery system encapsulating idarubicin shows superior kinetics and enhances tumoral drug uptake and response.

Increasing the bioavailable drug level in a tumor is the key to enhance efficacy of chemotherapy. Thermosensitive smart drug delivery systems (SDDS) in combination with local hyperthermia facilitate high local drug levels, thus improving uptake in the tumor. However, inability to rapidly and efficiently absorb the locally released drug results in reduced efficacy, as well as undesired redistribution of the drug away from the tumor to the system.

Hyperthermia and Temperature-Sensitive Nanomaterials for Spatiotemporal Drug Delivery to Solid Tumors.

Nanotechnology has great capability in formulation, reduction of side effects, and enhancing pharmacokinetics of chemotherapeutics by designing stable or long circulating nano-carriers. However, effective drug delivery at the cellular level by means of such carriers is still unsatisfactory. One promising approach is using spatiotemporal drug release by means of nanoparticles with the capacity for content release triggered by internal or external stimuli.

Sensitization of drug resistant sarcoma tumors by membrane modulation via short chain sphingolipid-containing nanoparticles.

Nanoparticles such as liposomes are able to overcome cancer treatment challenges such as multidrug resistance by increasing the bioavailability of the encapsulated drug, bypassing drug pumps or through targeting resistant cells. Here, we merge enhanced drug delivery by nanotechnology with tumor cell membrane modulation combined in a single formulation. This is achieved through the incorporation of Short chain sphingolipids (SCSs) in the liposomal composition, which permeabilizes cell membranes to amphiphilic drugs such as Doxorubicin (Dxr).

Hyperthermia and smart drug delivery systems for solid tumor therapy.

Chemotherapy is a cornerstone of cancer therapy. Irrespective of the administered drug, it is crucial that adequate drug amounts reach all cancer cells. To achieve this, drugs first need to be absorbed, then enter the blood circulation, diffuse into the tumor interstitial space and finally reach the tumor cells.

Acute cellular and vascular responses to photodynamic therapy using EGFR-targeted nanobody-photosensitizer conjugates studied with intravital optical imaging and magnetic resonance imaging.

Targeted photodynamic therapy (PDT) has the potential to selectively damage tumor tissue and to increase tumor vessel permeability. Here we characterize the tissue biodistribution of two EGFR-targeted nanobody-photosensitizer conjugates (NB-PS), the monovalent 7D12-PS and the biparatopic 7D12-9G8-PS. In addition, we report on the local and acute phototoxic effects triggered by illumination of these NB-PS which have previously shown to lead to extensive tumor damage.

A microcarrier-based spheroid 3D invasion assay to monitor dynamic cell movement in extracellular matrix.

Background: Cell invasion through extracellular matrix (ECM) is a critical step in tumor metastasis. To study cell invasion in vitro, the internal microenvironment can be simulated via the application of 3D models.

Results: This study presents a method for 3D invasion examination using microcarrier-based spheroids.

CREPT Promotes Melanoma Progression Through Accelerated Proliferation and Enhanced Migration by RhoA-Mediated Actin Filaments and Focal Adhesion Formation.

Melanoma is one of the most aggressive cancers, and patients with distant metastases have dire outcomes. We observed previously that melanoma progression is driven by a high migratory potential of melanoma cells, which survive and proliferate under harsh environmental conditions. In this study, we report that CREPT (cell-cycle related and expression-elevated protein in tumor), an oncoprotein highly expressed in other cancers, is overexpressed in melanoma cells but not melanocytes.

Liposomes targeted to MHC-restricted antigen improve drug delivery and antimelanoma response.

Purpose: Melanoma is the most aggressive form of skin cancer. Chemotherapy at a late stage fails due to low accumulation in tumors, indicating the need for targeted therapy.

Materials And Methods: To increase drug uptake by tumor cells, we have targeted doxorubicin-containing liposomes using a T-cell receptor (TCR)-like antibody (scFv G8 and Hyb3) directed against melanoma antigen A1 (MAGE-A1) presented by human leukocyte antigen A1 (M1/A1).

Spatiotemporal endothelial cell - pericyte association in tumors as shown by high resolution 4D intravital imaging.

Endothelial cells and pericytes are integral cellular components of the vasculature with distinct interactive functionalities. To study dynamic interactions between these two cells we created two transgenic animal lines. A truncated eNOS (endothelial nitric oxide synthase) construct was used as a GFP tag for endothelial cell evaluation and an inducible Cre-lox recombination, under control of the Pdgfrb (platelet derived growth factor receptor beta) promoter, was created for pericyte assessment.

Intravital Microscopy of Tumor-associated Vasculature Using Advanced Dorsal Skinfold Window Chambers on Transgenic Fluorescent Mice.

Tumor and tumor vessel development, as well as tumor response to therapeutics, are highly dynamic biological processes. Histology provides static information and is often not sufficient for a correct interpretation. Intravital evaluation, in which a process is followed in time, provides extra and often unexpected information.

Using In Vitro Live-cell Imaging to Explore Chemotherapeutics Delivered by Lipid-based Nanoparticles.

Conventional imaging techniques can provide detailed information about cellular processes. However, this information is based on static images in an otherwise dynamic system, and successive phases are easily overlooked or misinterpreted. Live-cell imaging and time-lapse microscopy, in which living cells can be followed for hours or even days in a more or less continuous fashion, are therefore very informative.

High-Resolution Intravital Microscopy of Tumor Angiogenesis.

Real-time evaluation of vascular effects in an animal skinfold window model by intravital microscopy (IVM) provides a powerful tool to improve insight into vascular development and vascular therapy. The potential of IVM to examine processes in tissues (e.g.

Melanomas prevent endothelial cell death under restrictive culture conditions by signaling through AKT and p38 MAPK/ ERK-1/2 cascades.

Although melanoma progression and staging is clinically well characterized, a large variation is observed in pathogenesis, progression, and therapeutic responses. Clearly, intrinsic characteristics of melanoma cells contribute to this variety. An important factor, in both progression of the disease and response to therapy, is the tumor-associated vasculature.

Formulation and optimization of idarubicin thermosensitive liposomes provides ultrafast triggered release at mild hyperthermia and improves tumor response.

Drug delivery through thermosensitive liposomes (TSL) in combination with hyperthermia (HT) has shown great potential. HT can be applied locally forcing TSL to release their content in the heated tumor resulting in high peak concentrations. To perform optimally the drug is ideally released fast (seconds) and taken up rapidly by tumor cells.

Pharmacokinetics, Tissue Distribution and Therapeutic Effect of Cationic Thermosensitive Liposomal Doxorubicin Upon Mild Hyperthermia.

Purpose: To evaluate pharmacokinetic profile, biodistribution and therapeutic effect of cationic thermosensitive liposomes (CTSL) encapsulating doxorubicin (Dox) upon mild hyperthermia (HT).

Methods: Non-targeted thermosensitive liposomes (TSL) and CTSL were developed, loaded with Dox and characterized. Blood kinetics and biodistribution of Dox-TSL and Dox-CTSL were followed in B16BL6 tumor bearing mice upon normothermia (NT) or initial hyperthermia conditions.

Enhanced Specificity and Drug Delivery in Tumors by cRGD-Anchoring Thermosensitive Liposomes.

Purpose: To develop RGD-targeted thermosensitive liposomes with increased tumor retention, improving drug release efficiency upon mild hyperthermia (HT) in both tumor and angiogenic endothelial cells.

Methods: Standard termosensitive liposomes (TSL) and TSL containing a cyclic Arg-Gly-Asp (cRGD) pentapeptide with the sequence Arg-Cys-D-Phe-Asp-Gly (RGDf[N-Met]C) were synthetized, loaded with Dox and characterized. Temperature- and time-dependent drug release profiles were assessed by fluorometry.

Plasma membrane targeting by short chain sphingolipids inserted in liposomes improves anti-tumor activity of mitoxantrone in an orthotopic breast carcinoma xenograft model.

Mitoxantrone (MTO) is clinically used for treatment of various types of cancers providing an alternative for similarly active, but more toxic chemotherapeutic drugs such as anthracyclines. To further decrease its toxicity MTO was encapsulated into liposomes. Although liposomal drugs can accumulate in target tumor tissue, they still face the plasma membrane barrier for effective intracellular delivery.