Cytotoxic effects of Cyclooxygenase enzyme inhibitor drugs (COX1, COX2) on KB cell line: An in-vitro study Dr. Hashemipour M.,1 Mehrabizadeh-Honarmand H.,1 Falsafi F.,2 Rajabalian S.,3 Hosseini R. 4 1 Assistant Professor, Department of Oral Medicine, School of Dentistry, Kerman University of Medical Sciences. Kerman, Iran. 2 Dental student. 3 Cellular and Molecular Biologist, Member of Kerman Neuroscience Research Center. Kerman, Iran. 4 Microbiologist. (Received 7 Oct, 2008 Accepted 20 August, 2009) Abstract Background and Aim: Cyclooxygenase enzyme inhibitors have been recently investigated regarding their inhibitory effect on cancer. The aim of the present study was to investigate the cytotoxic effects of cyclooxygenase enzyme inhibitor drugs on KB cell line (squamous cell carcinoma) in vitro. Materials and Methods: This experimental study used the powder of Ibuprophen, Indomethacin, Acetaminophen, Naproxen, Celecoxib, Mefenamic acid, Diclofenac Na, Aspirin and Piroxicam. These drugs were dissolved in proper solvents according to specified company instructions (SIGMA Company). The KB cell lines were proliferated through MTT Assay method. The concentration of drugs that causes 50% decrease in cell growth was computed (IC50). Post-hoc test was used to compare the effect of various concentrations of drugs on vitality of cells and variance test was applied to compare the mean of IC50 between various drugs by using SPSS version 13.5 statistical software. Results: This study showed that Celecoxibt, Mefenamic Acid and Diclofenac Na drugs have cytotoxicity effects on KB cell line with the IC50 values of 1.5, 4.5 and 15.4 µg/ml, respectively. Also, it was found that the Naproxen, Indomethacin and Aspirin drugs with the IC50 mean of 50µg/ml can inhibit cell growth. Conclusion: Celecoxib and Diclofenac Na drugs have cytotoxicity effects. Therefore, at the experimental stage, these medicines have the potential to be used as oral anticancer drugs. Key words: Carcinoma, Squamous Cell- KB Cells - Cyclooxygenase Inhibitors. Corresponding Author: Dr. Hashemipour M., Assistant Professor, Department of Oral Medicine, School of Dentistry, Kerman, University of Medical Sciences. Kerman, Iran. e.mail: m_s_hashemipour @ yahoo.com | 
