Assay the Cytotoxicity of Agents Targeting K-RAS Oncogene in Treatment Colorectal Cancer

Background: Cancer is considered as the second leading cause of death and the most popular kind of gastrointestinal cancer is colorectal cancer that resulted from genetic alterations progressed during a lifetime.In human cancer, the most frequently mutated oncogenes but have not produced to therapeutic attack are RAS genes (KRAS, NRAS and HRAS).Methotrexate is a cytotoxic chemotherapeutic agent, as it acts on cell cycle.Aims: This study aims to investigate the cytotoxicity effect MEX2R and MEX2O in human colorectal cells and to compare its action with MTX.MEX2R and MEX2O investigational agents as K-RAS oncogene blocker which inhibits the cell proliferation by targeting the cell cycle.Methods: LST 174 colorectal cell line was grown in RPMI-1640 media supplement with 10% heat inactivated fetal bovine serum and antibiotic 100IUs/ml penicillin with 100 g/ml streptomycin.The cells were incubated with agents and drugs for 24 hours.Cells were inoculated in 96-well microtiter plate (105 cells/well) for 48 hrs.The final concentration of the solvent never exceeded 0.1%.Triplicates were prepared for each individual dose.Color intensity was measured in an ELISA reader.The viability and inhibition % of cancer cell line after the specified time were then detected and the concentration that inhibit 50% of cell viability (IC50) was fitted and calculated.Results: There was no significant increase (P> 0.05) in cell growth inhibition as compared with control group at conc.(0.5,1,5 g/ml) of MEX2R, while there was a highly significant increase (P0.05) in inhibition of growth LST174 cells in conc.(25, 125,625 g/ml).Additionally, the conc.ofdrug that needed to inhibit a biological process or response by 50% (IC50) is about 411 mg/ml .The result showed that MEX2O has significant difference (P0.05) in LST174 cells growth inhibition in all concentrations (0.5,1.5.25,125,625 & 1000 g/ml) when compared with control(untreated) group.While, the concentration of drug that needed to inhibit a biological process or response by 50% (IC50) is about 317.69 mg/ml.Also, the result showed that MTX has significant increase (P0.05) in growth inhibition of LST174 cells in all concentrations (0.5,1,5,25,125,625,1000 g/ml) when compared with control group.While, the results showed that the conc. of drug that needed to inhibit a biological process or response by 50% (IC50) is about 803.8 mg/ml.Conclusion: MEX2R and MEX2O might be have a greater value in the treatment of this type of cancer than MTX as they act on the cell cycle as the tested drugs MEX2R & MEX2O acted on the cell cycle by targeting one of the main troubles that interfere with treatment of colorectal cancer which is K-RAS gene mutation and inhibit the cell proliferation.