Pyrimidine containing epidermal growth factor receptor kinase inhibitors: Synthesis and biological evaluation

Abstract

Structure-based design and synthesis of pyrimidine containing reversible epidermal growth factor receptor (EGFR) inhibitors 1a-d are reported. The compounds (1a-d) inhibited the EGFR kinase activity in vitro with IC range 740 nm to 3 μm. mRNA expression of EGFR downstream target genes, that is twist, c-fos and aurora were found to be altered upon treatment with compounds 1a-d. The compounds 1a-d exhibited excellent anticancer activity at low micromolar level (3.2-9 μm) in lung, colon and breast cancer cell lines. Furthermore, compounds induced the alteration in mitochondrial membrane potential and reactive oxygen species level and. Selected compound 1b was found to increase sub-G1 population indicative of cell death, the mode of cell death was apoptotic as evident from Annexin V verses propidium iodide assay. Molecular modelling further helped to investigate the binding recognition pattern of the compounds in ATP binding EGFR domain similar to erlotinib and dissimilar to WZ4002.

Anticancer activity of dihydropyrazolo[1,5‐c]quinazolines against rat C6 glioma cells via inhibition of topoisomerase II

“…The assay is based on the principle that annexin‐V binds to the apoptotic populations (detects the release of phosphatidylserine) under normal conditions whereas propidium iodide does not stain live or early/late apoptotic cells. In late apoptotic and necrotic cells, the integrity of the plasma and nuclear membranes declines allowing propidium iodide to pass through the membranes which further intercalate with nucleic acids and display red fluorescence . Compounds 1b and 1h induced early apoptosis at 5 μM and the mode of cell death was late apoptosis at 25 μM (Figure ).…”

“…The anticancer molecules tend to alter the intracellular ROS upon treatment . In order to know exact pattern of alteration in ROS levels, rat C‐6 glial cells were treated with the representative compounds 1a , 1b , 1d , and 1h for 48 h and measurements were done using DCFDA fluorescence assay.…”

“…The inhibition of specific target by the anticancer compounds tend to cause cell death and halt the cell cycle progression by arresting cell cycle . To investigate the specific phase of cell cycle arrested by our investigational compounds ( 1b , 1h ), rat C6 glioma cells were utilized and treatment was given at two concentrations, 5 and 25 μM for 24 h. The results showed significant changes in G1 pattern (33.59% in control, 87.06% in 1b , 82.21% in 1h ) treated at 5 μM concentration.…”

“…The compounds at 25 μM induced increase in sub‐G1 population several folds (82.21–87.06%) indicative of cell death. This peculiar feature may be attributed to the fact that compounds may be toxic to the glioma cells independent of the status of cell cycle or cells might be having mitotic catastrophy at the higher drug concentration (Figure ).…”

“…Submicromolar inhibitory values of available TopoII inhibitory drugs have rendered many opportunities to explore this research area . Through our previous experiences in the field of anticancer drug discovery and development, we thought of designing dihydropyrazolo[1,5‐ c ]quinazolines ( 1 ) as TopoII catalytic inhibitors after considering the interaction models of phosphoraminophosphonic acid–adenylate ester (ANP), an ATP analog, as well as N ‐acetyl pyrazoline ( 2 ), previously reported TopoII inhibitor (Figure ) at the catalytic domain of hTopoII enzyme (PDB entry: 1ZXM) . The rationale behind the design of 1 includes that (a) two aryl groups be flanked by a central heteroaromatic ring and one of the rings should be able to coordinate with Mg 2+ center of TopoII; (b) N ‐COCH 3 of 2 may be isosterically replaced with cyclized N‐C‐N‐Ar rigid framework in order to increase stability and avoid acid mediated cleavage that can occur with acetamido group of 2 in tumor microenvironment; and (c) extra phenyl ring may not only impart necessary lipophilicity to 1 to cross the blood brain barrier in GBM but may also get into the hydrophobic cavity of ATP domain in hTopoII.…”