pHLIP Peptides Target Acidity in Activated Macrophages.

Purpose: Acidity can be a useful alternative biomarker for the targeting of metabolically active cells in certain diseased tissues, as in acute inflammation or aggressive tumors. We investigated the targeting of activated macrophages by pH low insertion peptides (pHLIPs), an established technology for targeting cell-surface acidity.

Procedures: The uptake of fluorescent pHLIPs by activated macrophages was studied in cell cultures, in a mouse model of lung inflammation, and in a mouse tumor model.

pHLIP ICG for delineation of tumors and blood flow during fluorescence-guided surgery.

Fluorescence imaging has seen enduring use in blood flow visualization and is now finding a new range of applications in image-guided surgery. In this paper, we report a translational study of a new fluorescent agent for use in surgery, pHLIP ICG, where ICG (indocyanine green) is a surgical fluorescent dye used widely for imaging blood flow. We studied pHLIP ICG interaction with the cell membrane lipid bilayer, the pharmacology and toxicology in vitro and in vivo (mice and dogs), and the biodistribution and clearance of pHLIP ICG in mice.

PARaDIM: A PHITS-Based Monte Carlo Tool for Internal Dosimetry with Tetrahedral Mesh Computational Phantoms.

Mesh-type and voxel-based computational phantoms comprise the current state of the art for internal dose assessment via Monte Carlo simulations but excel in different aspects, with mesh-type phantoms offering advantages over their voxel counterparts in terms of their flexibility and realistic representation of detailed patient- or subject-specific anatomy. We have developed PARaDIM (pronounced "paradigm": Particle and Heavy Ion Transport Code System-Based Application for Radionuclide Dosimetry in Meshes), a freeware application for implementing tetrahedral mesh-type phantoms in absorbed dose calculations. It considers all medically relevant radionuclides, including α, β, γ, positron, and Auger/conversion electron emitters, and handles calculation of mean dose to individual regions, as well as 3-dimensional dose distributions for visualization and analysis in a variety of medical imaging software.

Peptides of pHLIP family for targeted intracellular and extracellular delivery of cargo molecules to tumors.

The pH (low) insertion peptides (pHLIPs) target acidity at the surfaces of cancer cells and show utility in a wide range of applications, including tumor imaging and intracellular delivery of therapeutic agents. Here we report pHLIP constructs that significantly improve the targeted delivery of agents into tumor cells. The investigated constructs include pHLIP bundles (conjugates consisting of two or four pHLIP peptides linked by polyethylene glycol) and Var3 pHLIPs containing either the nonstandard amino acid, γ-carboxyglutamic acid, or a glycine-leucine-leucine motif.

Synthesis and characterization of pHLIP coated gold nanoparticles.

Novel approaches in synthesis of spherical and multispiked gold nanoparticles coated with polyethylene glycol (PEG) and pH Low Insertion Peptide (pHLIP) were introduced. The presence of a tumor-targeting pHLIP peptide in the nanoparticle coating enhances the stability of particles in solution and promotes a pH-dependent cellular uptake. The spherical particles were prepared with sodium citrate as a gold reducing agent to form particles of 7.

Targeted imaging of urothelium carcinoma in human bladders by an ICG pHLIP peptide ex vivo.

Bladder cancer is the fifth most common in incidence and one of the most expensive cancers to treat. Early detection greatly improves the chances of survival and bladder preservation. The pH low insertion peptide (pHLIP) conjugated with a near-infrared fluorescent dye [indocyanine green (ICG)] targets low extracellular pH, allowing visualization of malignant lesions in human bladder carcinoma ex vivo.