The multi-kinase inhibitor sorafenib induces alterations in cellular signaling and apoptosis regulators in AT/RT cells in response to conditioned medium. Addition of autologous conditioned medium to briefly serum starved cells provides an avenue to evaluate the potential responses that may occur during autocrine/paracrine growth stimulation. In the presence of sorafenib (S), the conditioned medium induced reduced phosphorylation of Erk1/2 (BT12, KCCF1), Akt1/2 (BT12), c-Raf (BT12), Stat3 (BT12, KCCF1) compared to DMSO (D) control. Under these conditions, an increase in phosphorylation of c-Raf was noted in KCCF1 cells. However, the pro-survival protein Mcl-1 was suppressed by sorafenib in all three cell lines (A). Compared to basal medium (BM), conditioned medium (CM) induced phosphorylation of signaling regulators, such as Erk (B). The data shown are typical of three separate experiments.