Inhibition of PRAME expression causes cell cycle arrest and apoptosis in leukemic cells

The preferentially expressed antigen of melanoma (PRAME) is known as a tumor-associated antigen, but its function in leukemia remains unclear. We investigated the function with small interfering RNA (siRNA)-induced knockdown of PRAME in a K562 cell line. After PRAME siRNA transfection, proliferation was suppressed and cell cycle analysis showed G(0)/G(1) arrest, followed by apoptosis. PRAME siRNA-treated cells also showed changes in the genes affecting erythroid differentiation. We examined the PRAME expression levels and the S phase population of 32 acute leukemia patients at the time of diagnosis and relapse. An increase of the S phase population was accompanied by an increase of PRAME expression at relapse. Our results suggest that PRAME plays an important role in disease progression in acute leukemia. (C) 2011 Elsevier Ltd. All rights reserved.