RNA binding and thiolytic stability of a quinoline-containing helix-threading peptide

Trading places: Peptide and small molecule alternatives to oligonucleotide-based modulation of microRNA expression

It is well established that microRNA (miRNA) dysregulation is involved in the development and progression of various diseases, especially cancer. Emerging evidence suggests that small molecule and peptide agents can interfere with miRNA disease pathways. Despite this, very little is known about structural features that drive drug-miRNA interactions and subsequent inhibition. In this review, we highlight the advances made in the development of small molecule and peptide inhibitors of miRNA processing. Specifically, we attempt to draw attention to peptide features that may be critical for interaction with the miRNA secondary structure to regulate miRNA expression. We hope that this review will help to establish peptides as exciting miRNA expression modulators and will contribute towards the development of the first miRNA-targeting peptide therapy.

An aza-Diels–Alder route to quinoline-based unnatural amino acids and polypeptide surrogates

The synthesis of quinoline-based unnatural amino acids and the subsequent preparation of polypeptide surrogates from these building blocks on solid support.

Amino acid or peptide conjugates of acridine/acridone and quinoline/quinolone-containing drugs. A critical examination of their clinical effectiveness within a twenty-year timeframe in antitumor chemotherapy and treatment of infectious diseases

Acridines/acridones, quinolines/quinolones (chromophores) and their derivatives constitute extremely important family of compounds in current medicine. Great significance of the compounds is connected with antimicrobial and antitumor activities. Combining these features together in one drug seems to be long-term benefit, especially in oncology therapy. The attractiveness of the chromophore drugs is still enhanced by elimination their toxicity and improvement not only selectivity, specificity but also bioavailability. The best results are reached by conjugation to natural peptides. This paper highlights significant advance in the study of amino acid or peptide chromophore conjugates that provide highly encouraging data for novel drug development. The structures and clinical significance of amino acid or peptide chromophore conjugates are widely discussed.

Screening helix-threading peptides for RNA binding using a thiazole orange displacement assay

The fluorescent intercalator displacement assay using thiazole orange has been adapted to the study of RNA-binding helix-threading peptides (HTPs). This assay is highly sensitive with HTP-binding RNAs and provides binding affinity data in good agreement with quantitative ribonuclease footprinting without the need for radiolabeling or gel electrophoresis. The FID assay was used to define structure activity relationships for a small library of helix-threading peptides. Results of these studies indicate their RNA binding is dependent on peptide sequence, alpha-amino acid stereochemistry, and cyclization (vs linear peptides), but independent of macrocyclic ring size for the penta-, tetra- and tri-peptides analyzed.

Acridine-based agents with topoisomerase II activity inhibit pancreatic cancer cell proliferation and induce apoptosis

A series of substituted 9-aminoacridines is evaluated for antiproliferative activity toward pancreatic cancer cells. The results indicate that the compounds inhibit cell proliferation by inducing a G1-S phase arrest. A model is also developed that explains the molecular basis to inhibition through a DNA "threading" mechanism. We conclude that the drug-DNA complex formed blocks topoisomerase II binding and activity leading to catalytic inhibition of the enzyme and the induction of apoptosis and programmed cell death.