Application of a Best Practice Approach Using Resonant Mass Measurement for Biotherapeutic Product Characterization.

Characterizing and quantifying subvisible particles in protein drug products is critical to ensuring product quality. A variety of analytical methods are used to detect and make meaningful measurements of subvisible particles. Resonant mass measurement (RMM) is a novel technology that characterizes the subvisible particle content of samples on a particle-by-particle basis.

Impact of Sterilization Method on Protein Aggregation and Particle Formation in Polymer-Based Syringes.

The effects of sterilization methods on the storage stability of erythropoietin (EPO) in polymer-based syringes were assessed by quantifying protein oxidation, aggregation, and particle formation. Micro-particle counting and size exclusion chromatography coupled with a multi-angle light scattering detector demonstrated much lower levels of protein particles and aggregates for EPO stored for 12 weeks in steam-sterilized than in radiation (Rad)-sterilized syringes. Intermediate levels of damage were observed for EPO stored in ethylene oxide-sterilized syringes.

Characterization of Factors Affecting Nanoparticle Tracking Analysis Results With Synthetic and Protein Nanoparticles.

In many manufacturing and research areas, the ability to accurately monitor and characterize nanoparticles is becoming increasingly important. Nanoparticle tracking analysis is rapidly becoming a standard method for this characterization, yet several key factors in data acquisition and analysis may affect results. Nanoparticle tracking analysis is prone to user input and bias on account of a high number of parameters available, contains a limited analysis volume, and individual sample characteristics such as polydispersity or complex protein solutions may affect analysis results.

Characterization of Nanoparticle Tracking Analysis for Quantification and Sizing of Submicron Particles of Therapeutic Proteins.

Submicron particles may play important roles in therapeutic protein product quality, stability, and adverse effects in patients. However, quantitation of these particles has been challenging. Nanoparticle tracking analysis (NTA) is capable of both sizing and counting submicron particles.

Small Molecule, NSC95397, Inhibits the CtBP1-Protein Partner Interaction and CtBP1-Mediated Transcriptional Repression.

Carboxyl-terminal binding protein (CtBP) is a transcriptional corepressor that suppresses multiple proapoptotic and epithelial genes. CtBP is overexpressed in many human cancers, and its overexpression increases stem cell-like features, epithelial-mesenchymal transition, and cancer cell survival. Knockdown of CtBP also increases apoptosis independent of p53 in cell culture.

Allosteric inhibitors of the Eya2 phosphatase are selective and inhibit Eya2-mediated cell migration.

Eya proteins are essential co-activators of the Six family of transcription factors and contain a unique tyrosine phosphatase domain belonging to the haloacid dehalogenase family of phosphatases. The phosphatase activity of Eya is important for the transcription of a subset of Six1-target genes, and also directs cells to the repair rather than apoptosis pathway upon DNA damage. Furthermore, Eya phosphatase activity has been shown to mediate transformation, invasion, migration, and metastasis of breast cancer cells, making it a potential new drug target for breast cancer.

Identification of a selective small-molecule inhibitor series targeting the eyes absent 2 (Eya2) phosphatase activity.

Eya proteins are essential coactivators of the Six family of homeobox transcription factors and also contain a unique protein tyrosine phosphatase activity, belonging to the haloacid dehalogenase family of phosphatases. The phosphatase activity of Eya is important for a subset of Six1-mediated transcription, making this a unique type of transcriptional control. It is also responsible for directing cells to the repair instead of apoptosis pathway upon DNA damage.

Matrix metalloproteinase-assisted triggered release of liposomal contents.

We offer a novel methodology for formulating liposomes by incorporating sequence-specific collagen-mimetic peptides such that they are specifically "uncorked" by a matrix metalloproteinase, MMP-9. By encapsulating carboxyfluorescein (as a self-quenching fluorescent dye), we demonstrate that the time-dependent release of the dye from liposomes is due to the specific enzymatic cleavage of the surface-exposed collagen-mimetic peptides. The specificity of such cleavage is attested by the fact that the liposomal "uncorking" and their content release occur only by MMP-9 and not by a general proteolytic enzyme, trypsin, despite the fact that the collagen mimetic peptides contain the trypsin cleavage site.

"Uncorking" of liposomes by matrix metalloproteinase-9.

A triggered release methodology of liposomal contents via the enzyme MMP-9 is described.