Anticancer Drug Screening Methods Based On Electrochemical Signals Of Purine Bases

Objective The electrochemical behavior of the Human breast cancer(MCF-7) cells with and without xanthine oxidase has been studied to establish an enzyme-assistant electrochemical detecting system. The cytotoxicity of cyclophosphamide on MCF-7 cell activity was also evaluated by this system, which paves a new way to the application of enzyme-assistant electrochemical detecting system in screening anti-cancer drugs.Methods In this paper, the Human breast cancer(MCF-7) cells as a model cell, ionic liquids and multi-walled carbon composite modified electrode(MWNTs-IL / GCE) as working electrode, the electrochemical behaviors of purine standards and MCF-7 cells with and without xanthine oxidase have been studied by the linear scanning voltammetry. The standard linear regression curves between concentration and signal intensity have been made, and the attribution of electrochemical signals of MCF-7 cells were tested and verified by high performance liquid chromatography. The enzyme-assistant electrochemical detecting system has been established based on the above results. The cytotoxicity of drugs on MCF-7 cell activity was also evaluated by this system, and compare with the MTT assay, which proves the accuracy and feasibility of enzyme-assistant electrochemical method.Results The fragmented MCF-7 cell suspension exhibited two stronger signals at +0.623 V and +0.953 V, respectively. The signal at +0.623 V was due to G/X, and at +0.953 V was due to A/H in the fragmented MCF-7 cell suspension. The optimal detection conditions: p H 7.4, cells heated in 50 ℃ water bath for 30 min. Xanthine oxidase(XO) can catalyze the oxidation of H or X to uric acid(UA) and hydrogen peroxide(H2O2). The residual signal at +0.623 V was ascribed to G and that at +0.953 V was ascribed to A. The individual concentrations of G, A, X and H intracellular should be obtained based on the standard linear regression curves between concentration and signal intensity. And then, an enzyme-assistant electrochemical detecting system has been established. Finally, the screening experiment of anticancer drug has been finished by this system. During the experiment, the electrochemical signals in drug groups significantly decreased compared with that in the control group. The reliability of the enzymeassistant electrochemical method has been confirmed by the result of the MTT assay.Conclusions Two stronger signals in MCF-7 cell have been tested through electrochemistry method. Take the two peaks as index, an enzyme-assistant electrochemical detecting system has been constructed by introducing XO. The individual concentrations of G, X, A and H in MCF-7 cells can be detected simultaneously by enzyme-assistant electrochemical detecting method. The change of cell active have been studied by this electrochemical method, and the results are consistent with that of MTT assay, which indicated that the enzyme-assistant electrochemical detecting system can be expected to be applied to biochemical detection related to purine metabolism, especially screening anti-cancer drugs.