Adjuvant
therapy in
colorectal cancer has evolved to become the standard of care, whereas the
tumor capability of activating effective mechanisms of defence against both chemical and physical
cytotoxic agents represents a serious obstacle to the successful therapy of human
tumors. Therefore, the possibility to have an assay useful to measure the drug sensitivity of
tumor cells has a great importance. A number of cytotoxicity assays are currently available, each of them using a specific approach to detect different aspects of cell viability, such as cell integrity, proliferation and metabolic functions. The purpose of this study is to compare, under identical experimental conditions, three common cytotoxicity assays (
ATP-lite, MTT and CCK-8 assays) in the assessment of the anti-proliferative effects of
5-fluorouracil (5-FU) and
oxaliplatin (OHP) on three
colon cancer cell lines (WiDr, SW620 and HT-29). Regarding
5-FU, the three assays were found to be significantly correlated with a moderate or high correlation coefficient, whereas in the case of OHP we found different outcomes among the assays. Our study demonstrates that the
CCK-8 is the most sensitive assay for detecting changes of cell viability, suggesting that the viability measured in cells after drug exposure depends on several parameters like the drug used, the biological characteristics of the target cell and the specific approach employed by the method to detect distinct cell growth and metabolic functions.