MBC and ECBL libraries: outstanding tools for drug discovery

Druggable cavities and allosteric modulators of the cell division cycle 7 (CDC7) kinase

Cell division cycle 7 kinase (CDC7) has been found overexpressed in many cancer cell lines being also one of the kinases involved in the nuclear protein TDP-43 phosphorylation in vivo. Thus, inhibitors of CDC7 are emerging drug candidates for the treatment of oncological and neurodegenerative unmet diseases. All the known CDC7 inhibitors are ATP-competitives, lacking of selectivity enough for success in clinical trials. As allosteric sites are less conserved among kinase proteins, discovery of allosteric modulators of CDC7 is a great challenge and opportunity in this field.Using different computational approaches, we have here identified new druggable cavities on the human CDC7 structure and subsequently selective CDC7 inhibitors with allosteric modulation mainly targeting the pockets where the interaction between this kinase and its activator DBF4 takes place.

Discovery of Thiophene Derivatives as Potent, Orally Bioavailable, and Blood-Brain Barrier-Permeable Ebola Virus Entry Inhibitors

The endemic nature of the Ebola virus disease in Africa underscores the need for prophylactic and therapeutic drugs that are affordable and easy to administer. Through a phenotypic screening employing viral pseudotypes and our in-house chemical library, we identified a promising hit featuring a thiophene scaffold, exhibiting antiviral activity in the micromolar range. Following up on this thiophene hit, a new series of compounds that retain the five-membered heterocyclic scaffold while modifying several substituents was synthesized. Initial screening using a pseudotype viral system and validation assays employing authentic Ebola virus demonstrated the potential of this new chemical class as viral entry inhibitors. Subsequent investigations elucidated the mechanism of action through site-directed mutagenesis. Furthermore, we conducted studies to assess the pharmacokinetic profile of selected compounds to confirm its pharmacological and therapeutic potential.

Small molecule inhibitors of human LRRK2 enhance in vitro embryogenesis and microcallus formation for plant regeneration of crop and model species

In vitro plant embryogenesis and microcallus formation are systems which are required for plant regeneration, a process during which cell reprogramming and proliferation are critical. These systems offer many advantages in breeding programmes, such as doubled-haploid production, clonal propagation of selected genotypes, and recovery of successfully gene-edited or transformed plants. However, the low proportion of reprogrammed cells in many plant species makes these processes highly inefficient. Here we report a new strategy to improve in vitro plant cell reprogramming using small molecule inhibitors of mammalian leucine rich repeat kinase 2 (LRRK2), which are used in pharmaceutical applications for cell reprogramming, but never used in plants before. LRRK2 inhibitors increased in vitro embryo production in three different systems and species, microspore embryogenesis of oilseed rape and barley, and somatic embryogenesis in cork oak. These inhibitors also promoted plant cell reprogramming and proliferation in Arabidopsis protoplast cultures. The benzothiazole derivative JZ1.24, a representative compound of the tested molecules, modified the expression of the brassinosteroid (BR)-related genes BIN2, CPD, and BAS1, correlating with an activation of BR signaling. Additionally, the LRRK2 inhibitor JZ1.24 induced the expression of the embryogenesis marker gene SERK1-like. The results suggest that the use of small molecules from the pharmaceutical field could be extended to promote in vitro reprogramming of plant cells towards embryogenesis or microcallus formation in a wider range of plant species and in vitro systems. This technological innovation would help to develop new strategies to improve the efficiency of in vitro plant regeneration, a major bottleneck in plant breeding.

Discovery of new antimicrobial thiophene derivatives with activity against drug-resistant Gram negative-bacteria

Our aim is to identify new small molecules with antimicrobial potential, especially against colistin-resistant (Col-R) Acinetobacter baumannii and Escherichia coli. After initial hits identification by fingerprint similarity, MIC of 24 heterocyclic derivatives for A. baumannii and E. coli reference strains, and bactericidal activity of selected thiophenes against Col-R strains were determined. We analyzed changes in bacterial membrane permeability and the OMPs profile. Additionally, we determined bacterial adherence to host cells and performed molecular docking studies to assess their binding to bacterial targets. The compounds' MICs ranged from 4 to >64 mg/L. Thiophene derivatives 4, 5 and 8 exhibited MIC50 values between 16 and 32 mg/L for Col-R A. baumannii and 8 and 32 mg/L for Col-R E. coli. The time-kill curve assay demonstrated that thiophenes 4 and 8 had bactericidal effects against Col-R A. baumannii and E. coli. Furthermore, treatment with them resulted in increased membrane permeabilization and reduced adherence of these isolates to host cells. Finally, the docking studies showed a stronger binding affinity to CarO1 and Omp33 of A. baumannii and OmpW and OmpC of E. coli. These findings indicate that thiophene derivatives possess antibacterial activity against Col-R A. baumannii and E. coli, suggesting that they may enhance the repertoire of drug treatments against bacteria.