Human platelet lysate as validated replacement for animal serum to assess chemosensitivity.

Experiments with cultured mammalian cells represent an in vitro alternative to animal experiments. Fetal calf serum (FCS) is the most commonly used medium supplement worldwide. FCS contains a variable mixture of growth factors and cytokines that support cell proliferation. This undefined nature of FCS is a source of experimental variation, undesired immune responses, possible contaminations and, because of the way it is obtained, an ethical concern. Thus, alternative, defined, valid, and reliable medium supplements should be characterized in a large number of experiments. Human platelet lysate (hPL) is increasingly appreciated as an alternative to FCS. Since it is unclear whether cells respond differentially to clinically relevant chemotherapeutics inducing replicative stress and DNA damage (hydroxyurea, irinotecan), induction of reactive oxygen species (ROS), the tyrosine kinase inhibitor (TKi) imatinib, and novel epigenetic modifiers belonging to the group of histone deacetylase inhibitors (HDACi), we investigated these issues. Here we show that cancer cells derived from leukemia and colon cancer grow very similarly in culture media supplemented with FCS or outdated hPL. Notably, cells have practically identical proteomes under both culture conditions. Moreover, cells grown with FCS or hPL responded equally to all types of drugs and stress conditions that we tested. In addition, the transfection of blood cells by electroporation can be achieved under both conditions. Furthermore, we reveal that class I HDACs, but not HDAC6, are required for the expression of the pan-leukemic marker WT1 under various culture conditions. Hence, hPL is a moderately priced substitute for FCS in various experimental settings.