MYC represses PRDM1 in cHL. (A-B) cHL cell lines were treated with the small molecular weight MYC inhibitor 10058-F4 for 24 hours. Control cells were treated with equal volumes of DMSO. PRDM1 expression was determined by (A) Q-RT-PCR and (B) immunoblot. (C-F) L428 cells were transiently transfected with control siRNA (con) or siRNA against MYC. (C) Knockdown of MYC was confirmed 48 hours after transfection. (D) PRDM1 expression levels were measured by Q-RT-PCR 24 hours after transfection with siRNA. The experiment was repeated 3 times. The data are shown as mean ±SD. P value was determined using Student t test. (E) L428 cells were counted at indicated time points after transfection with con or MYC siRNA. Two independent experiments were performed. n.s., not statistically significant; P value was determined using Student t test. (F) The effect of MYC knockdown on cell-cycle distribution was measured by propidium iodide staining 48 hours after transfection with control (con) or MYC siRNA. Two independent experiments with 3 technical replicates each were performed. Data are presented as mean ±SD. P value was determined using Student t test. (G) Negative correlation between expression levels of MYC and PRDM1 in microdissected HRS cells from 29 cases. Data were mined from http://www.ncbi.nlm.nih.gov/geo/; GSE39133. ; p, 1-tailed Student t test; r, Pearson correlation coefficient.