Cassini expression in MEFs in response to DMSO, nilotinib, or 8093 resistance to nilotinib. (A) Viability of 8093 ALL cells over the course of a 9-day drug treatment with 16 nM nilotinib. MEFs were physically separated from the ALL cells by a Transwell. At day 9 (arrow), RNA was isolated from MEFs for gene expression profiling. Viability is expressed as total number of viable cells/total cell number. (B) Schematic indicating treatment of MEFs isolated for gene expression profiling. Left, irradiated MEFs were treated with DMSO or 16 nM nilotinib for 9 days. Right, irradiated MEFs were separated from 8093 ALL cells by a Transwell membrane. The co-cultures were treated with DMSO or 16 nM nilotinib for 9 days. (C) Confirmation of cassini expression using real-time RT/PCR on RNA isolated from MEFs. M, MEFs; D, DMSO; n, nilotinib (n = 3). Individual values for biological triplicates of samples M + D, M + n and M + ALL + n are indicated. Values are represented as mean ± SD of duplicate real-time RT/PCR. *p < 0.05 nil + ALL versus DMSO + ALL. (D) Cassini expression in MEFs treated with DMSO or 16 nM nilotinib, alone, or separated from overlying ALL cells by a Transwell membrane on the indicated days of drug treatment with 16 nM nilotinib or with DMSO (n = 1). *p < 0.05 d6 and d10 MEFs exposed to ALL/DMSO compared to MEFs exposed to ALL/nilotinib.