Cytogenetic studies of the drug methotrexate (MTX) on the blood lymphocytes of colon cancer patients .

Abstract

The aim of study is to investigate the  cytogenetic parameters in order to define the effect of methotrexate (MTX) on blood lymphocytes, manifested by blast index (BI), mitotic index (MI), replicative index (RI), and sister chromatid exchanges (SCEs). The results showed significant reduction in BI and MI and RI indices with MTX  concentrations (0.0, 0.2 ,0.5 ,1, 2, 4, 8, µg/ml) in comparison with the control. The results of BI showed significant reduction according to increasing of concentration. Of the drug in colon cancer patients, it gave 28.6 %, 18.6 %, 14.5%, 10.4%, 6.8 % , 6.7 %, 3.3% respectively. The results of (MI ) gave 3.6 %, 2.3%, 1.6%, 0.18%, 0.22%, 0.0%, 0.0 % respectively. The values of (RI(, gave 0.72% at zero concentration and 0.44% at concentration of 0.2µg/ml of M% TX and 0.27 % at concentration of 0.5µg/ml. On the other hand the SCE showed increases in the SCEs frequency in colon cancer samples in MTX concentration (0.0, 0.2, 0.5, µg/ml) which gave 8.47, 10.41, 10.49. respectively. The SCEs in the high concentration of drug (1,2,4,8 µg/ml) cannot be detected due to its  toxicity of the drug. The mutation fraction increased in colon cancer patient which gave 9 at 0.2 µg/ml, and 15.72  at 0.5 µg/ml and 4.1 in 1 µg/ml. The conclusion demonstrated decreasing in (MI), (BI) and (RI) and increasing in the SCEs frequencies and mutation fraction in colon cancer patients in comparison  with the control. The presence of mutant cells in lymphocytes of colon cancer that resistant to MTX, gave an idea about amplification in DHFR gene that regulate the activity of DHFR enzyme and also indicated the resistance of cancer cells to drugs.