Comparative study of cytotoxicity, viability and calorimetric in vitro tests for the antineoplastic drugs gemcitabine, oxaliplatin, paclitaxel and topotecan

Aim: The present work reports a comparative study between three different in vitro tests (cytotoxicity, viability, calorimetry) performed to assess the activity of antineoplastic drugs on tumor cells. Its aim is to define the experimental conditions under which these tests can be considered equivalent and interchangeable giving identical IC50 values and similar curves of toxicity. Methods: HT-29 human colorectal adenocarcinoma cell line and MeWo human melanoma cell line were used. The antineoplastic drugs tested were gemcitabine, oxaliplatin, paclitaxel and topotecan. Results: The cytotoxicity test gave the most satisfactory results: it allowed us to determine the IC50 for all drugs at 24 hours, offering the best profile of time-consuming. The viability test implies less operations and is cheaper but it is more time-consuming and prone to be influenced by different factors. Calorimetric measures did not always give reproducible results for low concentration of drugs, nevertheless the calorimetric test has a high sensitivity, is easy to use and offers high margin of safety for the operators. Conclusion: The cytotoxicity test, despite its labor costs allows to get the most satisfactory results. The viability test is safer for the operator but more time consuming. The calorimetric test requires a calibration curve for each tumor cell line and is still rather expensive. However, the use of modern multichannel calorimeters offers interesting developments for both routine analysis and initial toxicity screening of drugs.