NaB, SAHA, and TSA induce cell cycle arrest in G2/M phases in NB cells. A. S-type and N-type NB cell lines were treated with increasing doses of NaB, SAHA or TSA as indicated for 48 h. Cell viability was measured by MTS/PMS cell proliferation assays. Mean values of three independent experiments are shown. MYCN non amplified (n.a.) and MYCN amplified (a.) cells are indicated. B. Cell cycle arrest was detected by the propidium staining method after stimulation for 16 h with 10 mM of NaB, 2.5 μM of SAHA or 1.5 μM of TSA for IMR32 cells, and with 20 mM of NaB, 20 μM of SAHA or 5 μM of TSA in the presence (+) or absence (-) of zVAD-fmk for SH-EP cells. Percentage of cells in G1, S, G2, and sub-G1 phases are indicated.