Evaluation of antitumoral activity of drugs: comparison of different in vitro tests

To investigate the therapeutic activity of antitumoral drugs and corresponding Drug Delivery Systems it is possible to perform several in vitro tests which exploit different intracellular mechanisms: the aim of this work is to evaluate if these approaches could be considered reproducible, equivalent and/or interchangeable, taking also in account the time consuming and costs of each one. Antitumoral activity has been tested through three different approaches: cytotoxicity test evaluating inhibition of protein synthesis, cellular survavil evaluating a metabolic pathway and calorimetric analysis that measured cell calorimetric output. Oxaliplatin, Topotecan, Gemcitabine and Paclitaxel have been tested on different human tumor cell lines. Number of cells/well and time of drug incubation have been varied to point out an experimental schedule for each in vitro test, useful to evaluate the IC50 of a large number of antitumoral drugs. The results revealed that cytotoxicity test is the most versatile, less time consuming and not expensive if a lab deputed to radioactivity manipulation is working. Cellular survival test and calorimetric analysis are more time consuming and the second one also more expensive if the instrument is not available. Moreover the same experimental schedule, applied to the three approaches, showed different IC50 for most of the tested drugs, therefore the tests are not interchangeable.