2-Guanidino-quinazoline promotes the readthrough of nonsense mutations underlying human genetic diseases

Pharmaceuticals Promoting Premature Termination Codon Readthrough: Progress in Development

Around 11% of all known gene lesions causing human genetic diseases are nonsense mutations that introduce a premature stop codon (PTC) into the protein-coding gene sequence. Drug-induced PTC readthrough is a promising therapeutic strategy for treating hereditary diseases caused by nonsense mutations. To date, it has been found that more than 50 small-molecular compounds can promote PTC readthrough, known as translational readthrough-inducing drugs (TRIDs), and can be divided into two major categories: aminoglycosides and non-aminoglycosides. This review summarizes the pharmacodynamics and clinical application potential of the main TRIDs discovered so far, especially some newly discovered TRIDs in the past decade. The discovery of these TRIDs brings hope for treating nonsense mutations in various genetic diseases. Further research is still needed to deeply understand the mechanism of eukaryotic cell termination and drug-induced PTC readthrough so that patients can achieve the greatest benefit from the various TRID treatments.

Emerging Personalized Opportunities for Enhancing Translational Readthrough in Rare Genetic Diseases and Beyond

Nonsense mutations trigger premature translation termination and often give rise to prevalent and rare genetic diseases. Consequently, the pharmacological suppression of an unscheduled stop codon represents an attractive treatment option and is of high clinical relevance. At the molecular level, the ability of the ribosome to continue translation past a stop codon is designated stop codon readthrough (SCR). SCR of disease-causing premature termination codons (PTCs) is minimal but small molecule interventions, such as treatment with aminoglycoside antibiotics, can enhance its frequency. In this review, we summarize the current understanding of translation termination (both at PTCs and at cognate stop codons) and highlight recently discovered pathways that influence its fidelity. We describe the mechanisms involved in the recognition and readthrough of PTCs and report on SCR-inducing compounds currently explored in preclinical research and clinical trials. We conclude by reviewing the ongoing attempts of personalized nonsense suppression therapy in different disease contexts, including the genetic skin condition epidermolysis bullosa.

A High-Throughput Assay for In Vitro Determination of Release Factor-Dependent Peptide Release from a Pretermination Complex by Fluorescence Anisotropy-Application to Nonsense Suppressor Screening and Mechanistic Studies

Premature termination codons (PTCs) account for ~12% of all human disease mutations. Translation readthrough-inducing drugs (TRIDs) are prominent among the several therapeutic approaches being used to overcome PTCs. Ataluren is the only TRID that has been approved for treating patients suffering from a PTC disease, Duchenne muscular dystrophy, but it gives variable readthrough results in cells isolated from patients suffering from other PTC diseases. We recently elucidated ataluren's mechanism of action as a competitive inhibitor of release factor complex (RFC) catalysis of premature termination and identified ataluren's binding sites on the ribosome responsible for such an inhibition. These results suggest the possibility of discovering new TRIDs, which would retain ataluren's low toxicity while displaying greater potency and generality in stimulating readthrough via the inhibition of termination. Here we present a detailed description of a new in vitro plate reader assay that we are using both to screen small compound libraries for the inhibition of RFC-dependent peptide release and to better understand the influence of termination codon identity and sequence context on RFC activity.

Guanidino Quinazolines and Pyrimidines Promote Readthrough of Premature Termination Codons in Cells with Native Nonsense Mutations

Using small molecules to induce readthrough of premature termination codons is a promising therapeutic approach to treating genetic diseases and cancers caused by nonsense mutations, as evidenced by the widespread use of ataluren to treat nonsense mutation Duchene muscular dystrophy. Herein we describe a series of novel guanidino quinazoline and pyrimidine scaffolds that induce readthrough in both HDQ-P1 mammary carcinoma cells and mdx myotubes. Linkage of basic, tertiary amines with aliphatic, hydrophobic substituents to the terminal guanidine nitrogen of these scaffolds led to significant potency increases. Further potency gains were achieved by flanking the pyrimidine ring with hydrophobic substituents, inducing readthrough at concentrations as low as 120 nM and demonstrating the potential of these compounds to be used either in combination with ataluren or as stand-alone therapeutics.