LMP1+SLAMF1high cells are associated with drug resistance in Epstein-Barr virus-positive Farage cells

We isolated Farage cells expressing the cell surface marker SLAMF1. LMP1 and its target gene CCL22 were highly expressed in SLAMF1high Farage cells. These cells survived longer following treatment with a combination of cyclophosphamide, doxorubicin, vincristine and prednisone (CHOP). Genes associated with interferon-alpha, allograft rejection, NF-kB, STAT3 and 5 were also overexpressed in the surviving Farage cells. The three experimental conditions were designed: 1) Farage cells were sorted according to expression level of SLAMF1 and labeled as SLAM_high or SLAM_low.; 2) Farage cells treated with 1 μg/ml CHOP for 2 days and 3 days compared with untreated Farage cells; 3) Farage cells incubated with 1 μg/ml CHOP plus 50 ng/ml IL4 compared with 50 ng/ml IL4 alone for 2 days. Genome-wide analysis of all cell lines were performed using the Affymetrix HuGene ST 2.0 Array Platform. Genes with differential expression were analyzed using Statistical Analysis of Microarrays (SAM) software, and a signature of genes determined.