Structure-based design and synthesis of bicyclic fused-pyridines as MEK inhibitors

MEK inhibitors in cancer treatment: structural insights, regulation, recent advances and future perspectives

MEK1/2 are critical components of the RAS-RAF-MEK-ERK or MAPK signalling pathway that regulates a variety of cellular functions including proliferation, survival, and differentiation. In 1997, a lung cancer cell line was first found to have a MEK mutation (encoding MEK2P298L). MEK is involved in various human cancers such as non-small cell lung cancer (NSCLC), spurious melanoma, and pancreatic, colorectal, basal, breast, and liver cancer. To date, 4 MEK inhibitors i.e., trametinib, cobimetinib, selumetinib, and binimetinib have been approved by the FDA and several are under clinical trials. In this review, we have highlighted structural insights into the MEK1/2 proteins, such as the αC-helix, catalytic loop, P-loop, F-helix, hydrophobic pocket, and DFG motif. We have also discussed current issues with all FDA-approved MEK inhibitors or drugs under clinical trials and combination therapies to improve the efficacy of clinical drugs. Finally, this study addressed recent developments on synthetic MEK inhibitors (from their discovery in 1997 to 2022), their unique properties, and their relevance to MEK mutant inhibition.

Design, Synthesis and Biological Activity Evaluation of S-Substituted 1H-5-Mercapto-1,2,4-Triazole Derivatives as Antiproliferative Agents in Colorectal Cancer

Colon cancer is a widespread pathology with complex biochemical etiology based on a significant number of intracellular signaling pathways that play important roles in carcinogenesis, tumor proliferation and metastasis. These pathways function due to the action of key enzymes that can be used as targets for new anticancer drug development. Herein we report the synthesis and biological antiproliferative evaluation of a series of novel S-substituted 1H-3-R-5-mercapto-1,2,4-triazoles, on a colorectal cancer cell line, HT-29. Synthesized compounds were designed by docking based virtual screening (DBVS) of a previous constructed compound library against protein targets, known for their important role in colorectal cancer signaling: MEK1, ERK2, PDK1, VEGFR2. Among all synthesized structures, TZ55.7, which was retained as a possible PDK1 (phospholipid-dependent kinase 1) inhibitor, exhibited the most significant cytotoxic activity against HT-29 tumor cell line. The same compound alongside other two, TZ53.7 and TZ3a.7, led to a significant cell cycle arrest in both sub G0/G1 and G0/G1 phase. This study provides future perspectives for the development of new agents containing the 1,2,4-mercapto triazole scaffold with antiproliferative activities in colorectal cancer.

In silico investigation of new binding pocket for mitogen activated kinase kinase (MEK): Development of new promising inhibitors

It has been previously shown that the inhibition of mitogen activated protein kinase kinase (MEK) contributes to apoptosis and suppression of different cancer cells. Correspondingly, a number of MEK1/2 inhibitors have been designed and evaluated since 2001. However, they did not satisfy essential pharmacokinetic (PK) and pharmacodynamic (PD) properties thus, almost most of them were terminated in pre-clinical or clinical studies. This study aims to design new specific MEK1/2 inhibitors with improved PK/PD profiles to be used as alternative cancer medications. In first part of this study, a comprehensive screening, for the first time, was done on well-known MEK1/2 inhibitors using a number of computational programs such as AutoDock Tools 4.2 (ADT) and AutoDock Vina. Therefore a valuable training dataset as well as a reliable pharmacophore model were provided which were then used to design new inhibitors. According to the results of training dataset, Trametinib was determined as the best inhibitor provided, so far. So, Trametinib was used as the lead structure to design new inhibitors in this study. In second part of this investigation, a set of new allosteric MEK1/2 inhibitors were designed significantly improving the binding energy as well as the ADMET properties, suggesting more specific and stable ligand-receptor complexes. Consequently, the structures 14 and 15 of our inhibitors, as the most potent structures, are great substituents for Trametinib to be used and evaluated in clinical trials as alternative cancer drugs.