HDAC9 and melanoma: To determine whether GTPs reduce the levels of HDAC proteins in melanoma cells through proteasome-mediated degradation, A375 and Hs294t cells were treated with GTPs (60μg/ml) with and without treatment with MG132 (5, 10 and 20 μM conc.), an inhibitor of proteasomal degradation, for 48 h.