Using modulators with different mechanisms is effective in recovering the CFTR function, as demonstrated by combinations between correctors and Heat Shock Protein 70 (HSP70) inhibitors. The project aims to identify new HSP70 inhibitors that can be associated with correctors to improve the functionality of the CFTR channel.
Based on molecular modelling studies and using a starter point the structure of MKT-077, a commonly used inhibitor of HSP70, new molecules belonging to aminothiazoles were designed, ranked through “in silico” screenings and synthesized.
The first active compound to be identified was Ia, which showed an increased resistance to metabolism in comparison with MKT-077. This compound was used as a prototype to develop new analogue molecules.
About one hundred compounds were developed and evaluated in functional assays on human CF bronchial epithelial cells expressing the mutation F508del on CFTR, in the presence of CFTR correctors. Next, the mechanism of action as HSP70 inhibitors of the most effective derivatives was explored using the human recombinant HSP70 protein expressed in E. coli and measuring its ATPase activity.
Researchers designed libraries of compounds and evaluated their effects on cells in combination with different correctors. The molecules showed an inhibitory effect on the ATPase activity of HSP70. The obtained data allowed researchers to consider those compounds as prototypes able to target the HSP70 protein. Some of them displayed an increase in efflux by iodide efflux assays when administered with Lumacaftor.
The project confirmed the efficacy of HSP70 inhibitors in combination with correctors and allowed the identification of new molecules that can be now optimized.
Analyses on primary bronchial cells are underway to evaluate the best combinations between correctors and HSP70 inhibitors.