Metabolism-based structure optimization: Discovery of a potent and orally available tyrosine kinase ALK inhibitor bearing the tetracyclic benzo[b]carbazolone core

Pyrrole-containing hybrids as potential anticancer agents: An insight into current developments and structure-activity relationships

Cancer poses a significant threat to human health. Therefore, it is urgent to develop potent anti-cancer drugs with excellent inhibitory activity and no toxic side effects. Pyrrole and its derivatives are privileged heterocyclic compounds with significant diverse pharmacological effects. These compounds can target various aspects of cancer cells and have been applied in clinical settings or are undergoing clinical trials. As a result, pyrrole has emerged as a promising drug scaffold and has been further probed to get novel entities for the treatment of cancer. This article reviews recent research progress on anti-cancer drugs containing pyrrole. It focuses on the mechanism of action, biological activity, and structure-activity relationships of pyrrole derivatives, aiming to assist in designing and synthesizing innovative pyrrole-based anti-cancer compounds.

Current status of carbazole hybrids as anticancer agents

The drug resistance and low specificity of current available chemotherapeutics to cancer cells are the main reasons responsible for the failure of cancer chemotherapy and remain dramatic challenges for cancer therapy, creating an urgent need to develop novel anticancer agents. Carbazole nucleus, widely distributed in nature, is a predominant feature of a vast array of biologically active compounds. Carbazole derivatives exhibited potential antiproliferative activity against different cancer cell lines by diverse mechanisms, inclusive of arrest cell cycle and induce apoptosis, and several anticancer agents are carbazole-based compounds. Thus, carbazole derivatives represent a fertile source for discovery of novel anticancer therapeutic agents. Over the past several years, a variety of carbazole hybrids have been developed as potential anticancer agents. The present review focuses on the recent progress, from 2016 until now, in knowledge on anticancer properties, structure-activity relationships and mechanisms of action of carbazole hybrids to provide a basis for development of relevant therapeutic agents.

Identification of 1H-pyrazolo[3,4-b]pyridine derivatives as potent ALK-L1196M inhibitors

Anaplastic lymphoma kinase (ALK) has been recognised as a promising molecular target of targeted therapy for NSCLC. We performed SAR study of pyrazolo[3,4-b]pyridines to override crizotinib resistance caused by ALK-L1196M mutation and identified a novel and potent L1196M inhibitor, 10g. 10g displayed exceptional enzymatic activities (<0.5 nM of IC₅₀) against ALK-L1196M as well as against ALK-wt. In addition, 10g is an extremely potent inhibitor of ROS1 (<0.5 nM of IC₅₀) and displays excellent selectivity over c-Met. Moreover, 10g strongly suppresses proliferation of ALK-L1196M-Ba/F3 and H2228 cells harbouring EML4-ALK via apoptosis and the ALK signalling blockade. The results of molecular docking studies reveal that, in contrast to crizotinib, 10g engages in a favourable interaction with M1196 in the kinase domain of ALK-L1196M and hydrogen bonding with K1150 and E1210. This SAR study has provided a useful insight into the design of novel and potent inhibitors against ALK gatekeeper mutant.

Latest perspectives of orally bioavailable 2,4-diarylaminopyrimidine analogues (DAAPalogues) as anaplastic lymphoma kinase inhibitors: discovery and clinical developments

The course of anaplastic lymphoma kinase (ALK)-rearranged non-small-cell lung cancer (NSCLC) therapy has improved impressively. The Food and Drug Administration (FDA) has approved crizotinib (Xalkori, Pfizer) as a first-in-class tyrosine kinase inhibitor (TKI) that demonstrated a substantial objective response rate (ORR) and remarkable progression-free survival (PFS). However, acquired resistance to crizotinib is still a major concern especially as the central nervous system (CNS) remains the most common sites of relapse. To combat disease resistance, limited PFS and poor CNS exposure exhibited by crizotinib (Xalkori, Pfizer) led to the discovery of numerous next generation ALK-TKIs and surprisingly most of them are 2,4-Diarylaminopyrimidine Analogues (DAAPalogues). To date, DAAPalogues have been investigated extensively to display their superior potency against numerous kinase targets especially ALK/ROS1. This review describes hit-to-drug evolution strategies, activity spectra, milestones related to medicinal chemistry discovery efforts and scalable synthetic pathways of clinically emerging DAAPalouges which are either progressing as investigational or preclinical candidates. In addition, the significance of DAAPalogues to treat the patients with ALK+-NSCLC in clinical settings has been detailed. This review is beneficial for medicinal chemists and researchers contributing to discovering ALK-TKIs to overcome existing issues related to DAAPalouges in the drug discovery process.