The MTT assay yields a relatively lower result of growth inhibition than the ATP assay depending on the chemotherapeutic drugs tested.
Accurate assessment of the anti-growth effects of chemotherapeutics is immensely importance in cancer research with regard to drug discovery and toxicological safety. A number of in vitro cytotoxicity assays are used for these purposes. However, there is the possibility for different results in the assessments because the way they measure the viability of cancer cells is specific to each assay. In the present study, the performance of two common assays (MTT and ATP) in the assessment of anti-growth effects of chemotherapeutics on a lung cancer cell line (A549) was compared. The cells were treated with paclitaxel, docetaxel, gemcitabine, 5-fluorouracil (5-FU), etoposide, doxorubicin, epirubicin, cisplatin, 4-hydroperoxycyclophosphamide (4-HC) and carboplatin in six different concentrations. When taking all the drugs and inhibitions into account, a moderate correlation (r=0.670; p=0.01) between the assays was found. However, IC 50 values by the MTT assay were higher in 90% of the drugs than those found by the ATP assay. In addition to this, there was a statistically significant difference between the dose response curves of the assays, which was dependent on the drugs of choice. We recommend caution in comparing these assays to evaluate the anti-growth effects of chemotherapeutics because the MTT assay seem to give rise to relatively lower inhibition (higher viability) levels than the ATP assay, depending on the drugs of choice.
Ulukaya
Engin
E
Biochemistry and Clinical Chemistry Department, Medical School of Uludag University, 16059 Gorukle, Bursa, Turkey. eulukaya@uludag.edu.tr
Ozdikicioglu
Ferda
F
Oral
Arzu Yilmaztepe
AY
Demirci
Meral
M
D000255:Adenosine Triphosphate / Q000378:metabolism; D000970:Antineoplastic Agents / Q000008:administration & dosage / Q000494:pharmacology*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004354:Drug Screening Assays, Antitumor / Q000379:methods*; D006801:Humans; D066298:In Vitro Techniques; D020128:Inhibitory Concentration 50; D008175:Lung Neoplasms / Q000188:drug therapy*; D015203:Reproducibility of Results; D013778:Tetrazolium Salts / Q000378:metabolism; D013844:Thiazoles / Q000378:metabolism
D000970:Antineoplastic Agents; D013778:Tetrazolium Salts; D013844:Thiazoles; D000255:Adenosine Triphosphate; C022616:thiazolyl blue