Effective treatment of actinic keratosis on the hands with red light photodynamic therapy using BF-200 ALA.

BACKGROUND: Acral actinic keratosis (AK) lesions are considered difficult to treat, and published data for photodynamic therapy (PDT) on these lesions is limited. Thus, we evaluated sustained efficacy, safety, and satisfaction after PDT for AK on the hands. METHODS: We analysed subgroup data for treatment on the hands from a randomised, double-blind, intra-individual phase III study. All participants previously underwent up to two field-directed red light PDTs with 10% 5-aminolevulinic acid nanoemulsion gel (BF-200 ALA). Assessments included pain during PDT, clearance and recurrence rates, and satisfaction. RESULTS: 24 participants treated on the hands were included; 21 participants were analysed. Complete clearance rates with BF-200 ALA were 90.9% (lesion-based) and 76.2% (per participant's side), both markedly higher than with vehicle. The lesion recurrence rate with BF-200 ALA was 29.0%. Adverse events reflected the mode of action. Mean pain intensities were 4.8 ± 3.8 (BF-200 ALA) and 0.8 ± 2.1 (vehicle) on an 11-point numeric rating scale. Most participants (81.0%) rated their satisfaction with BF-200 ALA as very good or good. CONCLUSION: This subgroup analysis indicates that PDT with BF-200 ALA provides a suitable treatment for AK lesions on the hands.

Constrained Peptides with Fine-Tuned Flexibility Inhibit NF-Y Transcription Factor Assembly.

Protein complex formation depends on the interplay between preorganization and flexibility of the binding epitopes involved. The design of epitope mimetics typically focuses on stabilizing a particular bioactive conformation, often without considering conformational dynamics, which limits the potential of peptidomimetics against challenging targets such as transcription factors. We developed a peptide-derived inhibitor of the NF-Y transcription factor by first constraining the conformation of an epitope through hydrocarbon stapling and then fine-tuning its flexibility. In the initial set of constrained peptides, a single non-interacting α-methyl group was observed to have a detrimental effect on complex stability. Biophysical characterization revealed how this methyl group affects the conformation of the peptide in its bound state. Adaption of the methylation pattern resulted in a peptide that inhibits transcription factor assembly and subsequent recruitment to the target DNA.

Structure-Based Design of Non-natural Macrocyclic Peptides That Inhibit Protein-Protein Interactions.

Macrocyclic peptides can interfere with challenging biomolecular targets including protein-protein interactions. Whereas there are various approaches that facilitate the identification of peptide-derived ligands, their evolution into higher affinity binders remains a major hurdle. We report a virtual screen based on molecular docking that allows the affinity maturation of macrocyclic peptides taking non-natural amino acids into consideration. These macrocycles bear large and flexible substituents that usually complicate the use of docking approaches. A virtual library containing more than 1400 structures was screened against the target focusing on docking poses with the core structure resembling a known bioactive conformation. Based on this screen, a macrocyclic peptide 22 involving two non-natural amino acids was evolved showing increased target affinity and biological activity. Predicted binding modes were verified by X-ray crystallography. The presented workflow allows the screening of large macrocyclic peptides with diverse modifications thereby expanding the accessible chemical space and reducing synthetic efforts.