Phenylamino-pyrimidine (PAP) Privileged Structure: Synthesis and Medicinal Applications

Therapeutic potential of 1,2,3-triazole hybrids for leukemia treatment

Leukemia, a hematological malignancy originating from the bone marrow, is the principal cancer of childhood. In recent decades, improved remission rates and survival of patients with leukemia have been achieved due to significant breakthroughs in the treatment. However, chemoresistance and relapse are common, creating an urgent need for the search for novel pharmaceutical interventions. 1,2,3-Triazole is one of the most fascinating pharmacophores in the discovery of new drugs, and several 1,2,3-triazole derivatives have already been used in clinics or are under clinical evaluation for the treatment of cancers. In particular, 1,2,3-triazole hybrids could suppress tumor proliferation, invasion, and metastasis by inhibiting enzymes, proteins, and receptors in cancer cells, revealing their potential as putative antileukemic agents. This review covers the recent advances regarding the 1,2,3-triazole hybrids with potential antileukemic activity, focusing on the chemical structures, structure-activity relationship, and mechanisms of action, covering articles published from January 2017 to January 2022.

Benzimidazole hybrids as anticancer drugs: An updated review on anticancer properties, structure-activity relationship, and mechanisms of action (2019-2021)

Cancer, characterized by a deregulation of the cell cycle which mainly results in a progressive loss of cellular differentiation and uncontrolled cellular growth, remains a prominent cause of death across the world. Almost all currently available anticancer agents used in clinical practice have developed multidrug resistance, creating an urgent need to develop novel chemotherapeutics. Benzimidazole derivatives could exert anticancer properties through diverse mechanisms, inclusive of the disruption of microtubule polymerization, the induction of apoptosis, cell cycle (G2/M) arrest, antiangiogenesis, and blockage of glucose transport. Moreover, several benzimidazole-based agents have already been approved for the treatment of cancers. Hence, benzimidazole derivatives are useful scaffolds for the development of novel anticancer agents. In particular, benzimidazole hybrids could exert dual or multiple antiproliferative activities and had the potential to overcome drug resistance, demonstrating the potential of benzimidazole hybrids as potential prototypes for clinical deployment in the control and eradication of cancers. The purpose of the present review article is to provide a comprehensive landscape of benzimidazole hybrids as potential anticancer agents, and the structure-activity relationship as well as mechanisms of action are also discussed to facilitate the further rational design of more effective candidates, covering articles published from 2019 to 2021.

Hybrids of Imatinib with Quinoline: Synthesis, Antimyeloproliferative Activity Evaluation, and Molecular Docking

Imatinib (IMT) is the first-in-class BCR-ABL commercial tyrosine kinase inhibitor (TKI). However, the resistance and toxicity associated with the use of IMT highlight the importance of the search for new TKIs. In this context, heterocyclic systems, such as quinoline, which is present as a pharmacophore in the structure of the TKI inhibitor bosutinib (BST), have been widely applied. Thus, this work aimed to obtain new hybrids of imatinib containing quinoline moieties and evaluate them against K562 cells. The compounds were synthesized with a high purity degree. Among the produced molecules, the inhibitor 4-methyl-N3-(4-(pyridin-3-yl)pyrimidin-2-yl)-N1-(quinolin-4-yl)benzene-1,3-diamine (2g) showed a suitable reduction in cell viability, with a CC₅₀ value of 0.9 µM (IMT, CC₅₀ = 0.08 µM). Molecular docking results suggest that the interaction between the most active inhibitor 2g and the BCR-ABL1 enzyme occurs at the bosutinib binding site through a competitive inhibition mechanism. Despite being less potent and selective than IMT, 2g is a suitable prototype for use in the search for new drugs against chronic myeloid leukemia (CML), especially in patients with acquired resistance to IMT.

New Imatinib Derivatives with Antiproliferative Activity against A549 and K562 Cancer Cells

Tyrosine kinase enzymes are among the primary molecular targets for the treatment of some human neoplasms, such as those in lung cancer and chronic myeloid leukemia. Mutations in the enzyme domain can cause resistance and new inhibitors capable of circumventing these mutations are highly desired. The objective of this work was to synthesize and evaluate the antiproliferative ability of ten new analogs that contain isatins and the phenylamino-pyrimidine pyridine (PAPP) skeleton, the main pharmacophore group of imatinib. The 1,2,3-triazole core was used as a spacer in the derivatives through a click chemistry reaction and gave good yields. All the analogs were tested against A549 and K562 cells, lung cancer and chronic myeloid leukemia (CML) cell lines, respectively. In A549 cells, the 3,3-difluorinated compound (3a), the 5-chloro-3,3-difluorinated compound (3c) and the 5-bromo-3,3-difluorinated compound (3d) showed IC₅₀ values of 7.2, 6.4, and 7.3 μM, respectively, and were all more potent than imatinib (IC₅₀ of 65.4 μM). In K562 cells, the 3,3-difluoro-5-methylated compound (3b) decreased cell viability to 57.5% and, at 10 µM, showed an IC₅₀ value of 35.8 μM (imatinib, IC₅₀ = 0.08 μM). The results suggest that 3a, 3c, and 3d can be used as prototypes for the development of more potent and selective derivatives against lung cancer.

Tyrosine kinases in the pathogenesis of tissue fibrosis in systemic sclerosis and potential therapeutic role of their inhibition

Systemic sclerosis (SSc) is an idiopathic autoimmune disease with a heterogeneous clinical phenotype ranging from limited cutaneous involvement to rapidly progressive diffuse SSc. The most severe SSc clinical and pathologic manifestations result from an uncontrolled fibrotic process involving the skin and various internal organs. The molecular mechanisms responsible for the initiation and progression of the SSc fibrotic process have not been fully elucidated. Recently it has been suggested that tyrosine protein kinases play a role. The implicated kinases include receptor-activated tyrosine kinases and nonreceptor tyrosine kinases. The receptor kinases are activated following specific binding of growth factors (platelet-derived growth factor, fibroblast growth factor, or vascular endothelial growth factor). Other receptor kinases are the discoidin domain receptors activated by binding of various collagens, the ephrin receptors that are activated by ephrins and the angiopoetin-Tie-2s receptors. The nonreceptor tyrosine kinases c-Abl, Src, Janus, and STATs have also been shown to participate in SSc-associated tissue fibrosis. Currently, there are no effective disease-modifying therapies for SSc-associated tissue fibrosis. Therefore, extensive investigation has been conducted to examine whether tyrosine kinase inhibitors (TKIs) may exert antifibrotic effects. Here, we review the role of receptor and nonreceptor tyrosine kinases in the pathogenesis of the frequently progressive cutaneous and systemic fibrotic alterations in SSc, and the potential of TKIs as SSc disease-modifying antifibrotic therapeutic agents.