Untersuchung zur Zellulären Pharmakologie von peptidischen und nichtpeptidischen Wirkstoffmolekülen

Abstract

Untersuchung zur Zellulären Pharmakologie von peptidischen und nichtpeptidischen Wirkstoffmolekülen mittels Fluoreszenzkorrelationsspektroskopie, konfokaler Mikroscopie usw.

For more than 100 years, trials in “systemic” or “clinical” pharmacology have been revealing the behavior of drug-like molecules in organisms. In this context pharmacology is divided in pharmacodynamics and pharmacokinetics. Whereas pharmacodynamics deal with the impact of a drug or a combination of those on organisms, pharmacokinetics in turn describe the impact of an organism and its metabolic systems on the fate of the drug compound. Moreover, in the last decades many biophysical and bioanalytical techniques were developed and established to display the exact binding properties of defined binding partners, an area of activity that is often named “molecular pharmacology”. Especially highthroughput screening approaches play a key role in today's drug discovery. In cell culturebased approaches mostly the impact of a molecule on a single response that can be easily read out is displayed. Between systemic and molecular pharmacology there is still a large gap and the behavior of a molecule in its cellular and subcellular context is misleadingly assumed to be rather simple: the compound penetrates the plasma membrane, binds to its dedicated target structure and thereby executes its mode of action. In reality, the processes are highly complex and there is still an unmet need to untangle the network of a compound's behavior in its physiological context. In future drug discovery many questions that deal with cellular pharmacology will certainly play a crucial role: How does a certain molecule enter the cell? Can this be influenced by combinations of drugs or by formulations? Where is the molecule located intracellularly? What is its binding profile like in its native environment? Does it diffuse freely or is it bound to membranes, proteins or other high-molecular weight structures? What is the unbound concentration in the direct environment of the target structure? How fast is a molecule degraded, exported or transported within or out of the cell? This thesis addresses some of the most relevant questions concerning “cellular pharmacology”. In one chapter the modular assembly of peptides conjugated to a chemically inert polymeric backbone and the impact of a backbone on the activity of the peptides as well as the import efficiency of the conjugates is investigated. These results should support the untangling of signal transduction networks. A second chapter concentrates on the effect of polymer-conjugation on the peptide stability, a third one on the residence time of peptides and conjugates within cells and therefore the time in which these can influence signal transduction networks. A forth chapter focuses on the tertiary structure-based mode of action of a cell-penetrating peptide derived from the human milk protein human lactoferrin and its ability to facilitate the uptake of a cargo. And, finally, one chapter focuses on the intracellular binding profile of small molecule anti-cancer drugs.