Belinostat-resistant TCL cells exhibit downregulated IRF1 and STAT1 expression. (A) Transcriptome analysis of HuT-78 and Karpas-299 parental and resistant cell lines reveal significant alterations in antiviral genes, including reductions in STAT1 and IRF1. Gene expression changes were determined by using Affymetrix expression arrays. Virus-related genes with significant induction/repression are illustrated in the heat maps. (B-C) Real-time qPCR analysis of STAT1 and IRF1 levels. STAT1 and IRF1 expression was measured by real-time qPCR in parental and belinostat-resistant TCL cells. Data are shown as mean ± SD (n = 3). *P < .05 indicates a significant difference compared with parental cells. (D) STAT1 and IRF1 protein expression is decreased in belinostat-resistant TCL cells. IRF1, phospho-STAT1, and STAT1 protein expression was determined by immunoblotting. (E) Belinostat-resistant cells show reduced IRF1 and STAT1 promoter site binding. ChIP assays were used to quantify the binding of IRF1 and STAT1 to their respective promoters. Absence of Ig (- Ig) served as a negative control, and normal rabbit IgG was used as an isotype control. Histone H3 (H3) served as a positive control, and chromatin input was used as a loading control. NC represents a negative control for the PCR reaction.