Tetrahydropyridine LIMK inhibitors: Structure activity studies and biological characterization

LIM Kinases, LIMK1 and LIMK2, have become promising targets for the development of inhibitors with potential application for the treatment of several major diseases. LIMKs play crucial roles in cytoskeleton remodeling as downstream effectors of small G proteins of the Rho-GTPase family, and as major regulators of cofilin, an actin depolymerizing factor. In this article we describe the conception, synthesis, and biological evaluation of novel tetrahydropyridine pyrrolopyrimidine LIMK inhibitors. Homology models were first constructed to better understand the binding mode of our preliminary compounds and to explain differences in biological activity. A library of over 60 products was generated and in vitro enzymatic activities were measured in the mid to low nanomolar range. The most promising derivatives were then evaluated in cell on cofilin phosphorylation inhibition which led to the identification of 52 which showed excellent selectivity for LIMKs in a kinase selectivity panel. We also demonstrated that 52 affected the cell cytoskeleton by disturbing actin filaments. Cell migration studies with this derivative using three different cell lines displayed a significant effect on cell motility. Finally, the crystal structure of the kinase domain of LIMK2 complexed with 52 was solved, greatly improving our understanding of the interaction between 52 and LIMK2 active site. The reported data represent a basis for the development of more efficient LIMK inhibitors for future in vivo preclinical validation.

The DCMU Herbicide Shapes T-cell Functions By Modulating Micro-RNA Expression Profiles

DCMU [N-(3,4-dichlorophenyl)-N-dimethylurea] or diuron is a widely used herbicide, which can cause adverse effects on human, especially on immune cells, due to their intrinsic properties and wide distribution. These cells are important for fighting not only against virus or bacteria but also against neoplastic cell development. We developed an approach that combines functional studies and miRNA and RNA sequencing data to evaluate the effects of DCMU on the human immune response against cancer, particularly the one carried out by CD8+ T cells. We found that DCMU modulates the expression of miRNA in a dose-dependent manner, leading to a specific pattern of gene expression and consequently to a diminished cytokine and granzyme B secretions. Using mimics or anti-miRs, we identified several miRNA, such as hsa-miR-3135b and hsa-miR-21-5p, that regulate these secretions. All these changes reduce the CD8+ T cells’ cytotoxic activity directed against cancer cells, in vitro and in vivo in a zebrafish model. To conclude, our study suggests that DCMU reduces T-cell abilities, participating thus to the establishment of an environment conducive to cancer development.