Quantitative analysis of cell signaling and drug action via mass spectrometry-based systems level phosphoproteomics.

Protein phosphorylation is a primary form of information transfer in cell signaling pathways and plays a crucial role in regulating biological responses. Aberrant phosphorylation has been implicated in a number of diseases, and kinases and phosphatases, the cellular enzymes that control dynamic phosphorylation events, present attractive therapeutic targets. However, the innate complexity of signaling networks has presented many challenges to therapeutic target selection and successful drug development.

Profiling protein tyrosine phosphorylation: a quantitative 45-plex peptide-based immunoassay.

Cellular homeostasis and responses to stimuli are mediated by complex signaling network events dominated by changes in protein phosphorylation states. Understanding information flow in the network is essential for correlating signaling changes to cell physiology. Tyrosine phosphorylation constitutes only a small portion of all protein phosphorylation, but its importance is manifested by the significant role it plays in diseases such as cancer.

Quantitative measurement of epidermal growth factor receptor-mitogen-activated protein kinase signal transduction using a nine-plex, peptide-based immunoassay.

Aberrant epidermal growth factor receptor (EGFR, ErbB1) signaling is implicated in cell transformation, motility, and invasion in a variety of cell types, and EGFR is the target of several anticancer drugs. However, the kinetics of EGFR signaling and the individual contributions of site-specific phosphorylation events remain largely unknown. A peptide-based, multiplex immunoassay approach was developed to simultaneously measure both total and phosphorylated protein in a single sample.

The challenges of bringing autologous HSP-based vaccines to commercial reality.

Based on genetic diversity in the population, there is an expectation, born out by decades of experience, that a given drug or treatment will not be equally efficacious for all patients. While this fact cannot be avoided, with ever increasing knowledge of the drug's biological mechanism of action and the relationship between efficacy and the patient's genetic profile, more directed treatments, with greater potential for efficacy are becoming possible. For example, Herceptin, Genentech's antibody based treatment for HER2 positive metastatic breast cancer, is prescribed based on the results of a diagnostic test, the outcome of which is able to screen out patients who have no chance of responding to the treatment.