As and As/IFN treatment affect 2 distinct gene networks in HTLV-1⁺cells. Microarray analysis of the gene expression profile of HuT-102 cells in response to treatment with IFN, As, and combined treatment with As/IFN at 12, 24, and 48 hours. The gene expression profile is presented as a matrix in which the rows represent individual array clones and the columns, individual mRNA samples from each of the 12 experiments. The relative level of gene expression is depicted according to the color scale shown. Gray squares indicate missing or excluded data. The results displayed represent the changes in gene expression over time in relation to the 12-hour control. Asterisks denote a sequence verified clone, IM indicates an IMAGE consortium clone identification number, and LC a Lymphochip clone identification number. (A) Selected genes up-regulated by IFN and As/IFN, but not by As alone. (B) Down-regulation of a selected number of NF-κB–dependent genes by As and As/IFN treatment at 12, 24, and 48 hours (details described in “Materials and methods”). (C) Cell cycle arrest by combined treatment with As/IFN. Proliferation signature genes (see “Materials and methods”) exhibit massive down-regulation at 48 hours after combined treatment with As/IFN.