Increasing of antitumor effect of decitabine against classical Hodgkin lymphoma (cHL) by targeting decitabine-activated pro-survival pathways

We found that 5-Aza-dC/decitabine induces various prosurvival pathways (JAK-STAT-, NFkB-, MEK/ERK- and PI3K/AKTpathway) in cHL cell lines. Inhibition of these pathways with specific small molecular weight inhibitors potentiates the antitumor effect of 5-Aza-dC. L1236 and L428 cells were treated with 1µM of 5-Aza-dC for 24h and were then washed out. After additional 72 h incubation in normal medium, total RNA was isolated with RNeasy mini kit (QIAGEN). Microarray analyses were performed using 200 ng of total RNA as starting material and 5.5 µg ssDNA per hybridization (GeneChip Fluidics Station 450; Affymetrix, Santa Clara, CA). The total RNAs were amplified and labeled following the Whole Transcript (WT) Sense Target Labeling Assay (http://www.affymetrix.com). Labeled ssDNA was hybridized to Human Gene 1.0 ST Affymetrix GeneChip arrays (Affymetrix, Santa Clara, CA). The chips were scanned with an Affymetrix GeneChip Scanner 3000 and subsequent images analyzed using Affymetrix® Expression Console Software (Affymetrix). Probe level data were obtained using the robust multichip average (RMA) normalization algorithm.