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Increased efficacy of VX-809 in different cellular systems results from an early stabilization effect of F508del-CFTR.

Farinha CM, Sousa M, Canato S, Schmidt A, Uliyakina I, Amaral MD - Pharmacol Res Perspect (2015)

Bottom Line: Nevertheless, biochemical data show that VX-809 significantly stabilizes F508del-CFTR immature form, an effect that is not observed for C3 nor C4.VX-809 and C3 also significantly increase accumulation of immature CFTR.Our data suggest that VX-809 increases the stability of F508del-CFTR immature form at an early phase of its biogenesis, thus explaining its increased efficacy when inducing its rescue.

View Article: PubMed Central - PubMed

Affiliation: University of Lisboa, Faculty of Sciences, BioISI - Biosystems & Integrative Sciences Institute Campo Grande-C8, 1749-016, Lisboa, Portugal.

ABSTRACT
Cystic fibrosis (CF), the most common recessive autosomal disease among Caucasians, is caused by mutations in the gene encoding the CF transmembrane conductance regulator (CFTR) protein. The most common mutation, F508del, leads to CFTR impaired plasma membrane trafficking. Therapies modulating CFTR basic defect are emerging, such as VX-809, a corrector of F508del-CFTR traffic which just succeeded in a Phase III clinical trial. We recently showed that VX-809 is additive to two other correctors (VRT-325 and compound 4a). Here, we aimed to determine whether the differential rescuing by these compounds results from cell-specific factors or rather from distinct effects at the early biogenesis and/or processing. The rescuing efficiencies of the above three correctors were first compared in different cellular models (primary respiratory cells, cystic fibrosis bronchial epithelial and baby hamster kidney [BHK] cell lines) by functional approaches: micro-Ussing chamber and iodide efflux. Next, biochemical methods (metabolic labeling, pulse-chase and immunoprecipitation) were used to determine their impact on CFTR biogenesis / processing. Functional analyses revealed that VX-809 has the greatest rescuing efficacy and that the relative efficiencies of the three compounds are essentially maintained in all three cellular models tested. Nevertheless, biochemical data show that VX-809 significantly stabilizes F508del-CFTR immature form, an effect that is not observed for C3 nor C4. VX-809 and C3 also significantly increase accumulation of immature CFTR. Our data suggest that VX-809 increases the stability of F508del-CFTR immature form at an early phase of its biogenesis, thus explaining its increased efficacy when inducing its rescue.

No MeSH data available.


Related in: MedlinePlus

F508del-CFTR accumulation under treatment with VX-809, C3, and C4 correctors. BHK cells expressing F508del-CFTR (A) were incubated with radioactive methionine for the indicated periods of time at 37°C. (B) Rate of accumulation was measured by the increase in labeling relatively to the first time point (10 min). Data are mean ± SEM at each point (n = 4). *P < 0.05 relative to DMSO.
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fig05: F508del-CFTR accumulation under treatment with VX-809, C3, and C4 correctors. BHK cells expressing F508del-CFTR (A) were incubated with radioactive methionine for the indicated periods of time at 37°C. (B) Rate of accumulation was measured by the increase in labeling relatively to the first time point (10 min). Data are mean ± SEM at each point (n = 4). *P < 0.05 relative to DMSO.

Mentions: Statistical analysis was made using two-tailed Student’s t-tests for simple (paired) comparisons (Fig. 6) and one-way Analysis of variance (ANOVA) followed by post hoc Tukey’s test for multiple comparisons (Figs.5). Statistical significance was considered for P < 0.05. The GraphPad Prism (La Jolla, CA, USA) version 5.0f software was used for statistical analysis.


Increased efficacy of VX-809 in different cellular systems results from an early stabilization effect of F508del-CFTR.

Farinha CM, Sousa M, Canato S, Schmidt A, Uliyakina I, Amaral MD - Pharmacol Res Perspect (2015)

F508del-CFTR accumulation under treatment with VX-809, C3, and C4 correctors. BHK cells expressing F508del-CFTR (A) were incubated with radioactive methionine for the indicated periods of time at 37°C. (B) Rate of accumulation was measured by the increase in labeling relatively to the first time point (10 min). Data are mean ± SEM at each point (n = 4). *P < 0.05 relative to DMSO.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4492728&req=5

fig05: F508del-CFTR accumulation under treatment with VX-809, C3, and C4 correctors. BHK cells expressing F508del-CFTR (A) were incubated with radioactive methionine for the indicated periods of time at 37°C. (B) Rate of accumulation was measured by the increase in labeling relatively to the first time point (10 min). Data are mean ± SEM at each point (n = 4). *P < 0.05 relative to DMSO.
Mentions: Statistical analysis was made using two-tailed Student’s t-tests for simple (paired) comparisons (Fig. 6) and one-way Analysis of variance (ANOVA) followed by post hoc Tukey’s test for multiple comparisons (Figs.5). Statistical significance was considered for P < 0.05. The GraphPad Prism (La Jolla, CA, USA) version 5.0f software was used for statistical analysis.

Bottom Line: Nevertheless, biochemical data show that VX-809 significantly stabilizes F508del-CFTR immature form, an effect that is not observed for C3 nor C4.VX-809 and C3 also significantly increase accumulation of immature CFTR.Our data suggest that VX-809 increases the stability of F508del-CFTR immature form at an early phase of its biogenesis, thus explaining its increased efficacy when inducing its rescue.

View Article: PubMed Central - PubMed

Affiliation: University of Lisboa, Faculty of Sciences, BioISI - Biosystems & Integrative Sciences Institute Campo Grande-C8, 1749-016, Lisboa, Portugal.

ABSTRACT
Cystic fibrosis (CF), the most common recessive autosomal disease among Caucasians, is caused by mutations in the gene encoding the CF transmembrane conductance regulator (CFTR) protein. The most common mutation, F508del, leads to CFTR impaired plasma membrane trafficking. Therapies modulating CFTR basic defect are emerging, such as VX-809, a corrector of F508del-CFTR traffic which just succeeded in a Phase III clinical trial. We recently showed that VX-809 is additive to two other correctors (VRT-325 and compound 4a). Here, we aimed to determine whether the differential rescuing by these compounds results from cell-specific factors or rather from distinct effects at the early biogenesis and/or processing. The rescuing efficiencies of the above three correctors were first compared in different cellular models (primary respiratory cells, cystic fibrosis bronchial epithelial and baby hamster kidney [BHK] cell lines) by functional approaches: micro-Ussing chamber and iodide efflux. Next, biochemical methods (metabolic labeling, pulse-chase and immunoprecipitation) were used to determine their impact on CFTR biogenesis / processing. Functional analyses revealed that VX-809 has the greatest rescuing efficacy and that the relative efficiencies of the three compounds are essentially maintained in all three cellular models tested. Nevertheless, biochemical data show that VX-809 significantly stabilizes F508del-CFTR immature form, an effect that is not observed for C3 nor C4. VX-809 and C3 also significantly increase accumulation of immature CFTR. Our data suggest that VX-809 increases the stability of F508del-CFTR immature form at an early phase of its biogenesis, thus explaining its increased efficacy when inducing its rescue.

No MeSH data available.


Related in: MedlinePlus