Evaluation of cytotoxicity mechanism of two cyclo-oxygenase-2 inhibitors in leukemia cell line

Leukemia is considered one of the main causes of death، and current chemotherapeutic agents are unable to provide optimal responses due to chemo-resistance. Therefore، there is a constant need for new drugs. Cyclooxygenase- 2 (COX-2) inhibitors can be helpful by reducing the necessary dose of routine chemotherapeutic drugs. Herein، we evaluated the cytotoxicity activity as well as the morphological changes induced by compounds A (3-(4- chlorophenyl) -5- (4-flurophenyl) -4-Phenyl-4،5-dihydro-1،2،4-oxadiazole) and B (3،5-bis(4 chlorophenyl) -4-Phenyl-4،5- dihydro-1،2،4-oxadiazole) as COX-2 inhibitors. In addition، the upstream mechanism was investigated by measuring expression of nuclear factor kappa light-chain-enhancer of activated B cells (NF-κB) and ferritin heavy chain (FHC). K562 leukemia cell line was cultured، treated with the above-mentioned two compounds، and their IC50 values obtained. Compounds A and B-treated cells were analyzed for morphologic changes by fluorescence microscope after 16 h incubation at their IC50 concentrations. The protein fraction of whole cell lysate was prepared to evaluate NF- κB by NF-κB assay kit. FHC expression was also determined using western blotting. Treatment of cells with the compounds A and B resulted in considerable apoptotic morphological changes according to DAPI staining. NF-κB assay demonstrated its significant decrease due to compound B. Our experiment also revealed a significant reduction in FHC expression after treatment with compound B. Compound B can induce cytotoxicity and morphological changes in leukemic cell line probably through NF-κB/FHC pathway.