The need for new, effective drugs based on bioactive substances has increased greatly in recent years. The predictions for the future also reveal strong growth in this segment. This trend was picked up on in the Vascular Biology Unit and a technology platform was created which is able to develop and evaluate peptides both against multi-resistant hospital germs and also against tumor cells. This DNA-based technology allows an appropriate, antibiotically effective peptide to be developed against every relevant hospital germ by means of a high-throughput technique. Some of these antimicrobial peptides have a broad-spectrum effect and could thus be applied against a number of different types of bacteria or also pathogenic fungi (e.g. candida albicans).
During the course of 2012, several sequence libraries were established with partly differing ranges of efficacy, e.g. against human-pathogenic oral germs (cariogenic germs such as streptococcus mutans, streptococcus sobrinus or pathogens associated with paradontitis such as actinobacillus actinomycetemcomitans, porphyromonas gingivalis), germs found in the gastrointestinal tract (heliobacter pylori) and also against germs found in the respiratory tract (haemophilus influenzae).
The use of bioactive substances from plants, insects and amphibians for the treatment of inflammations and also tumor diseases (e.g. the so-called ”frog vaccine”) has been common practice for a number of years, particularly among the indigenous peoples of Central and South America. This is why, together with the Immunotherapy – Oncology Unit, peptides from the skin secretion of tropical frog species (e.g. phyllomedusa bicolor) were cloned in an additional experimental approach and several amino acids from these peptides were mutated at defined positions. Compared with the original peptides, it could be demonstrated in vitro that the cytotoxicity of these peptides, in comparison with tumor cells, could be increased by modifying the amino acid sequence, while control cells showed a comparably high level of resistance. Although the mechanism of action of these peptides was not yet able to be clarified, the assumption suggests that the different composition and net charge of the cell membrane of tumor cells and non-tumor cells play a decisive role here. Moreover, some of these peptides may have an additional, immunomodulatory effect.