A B Supplementary Figure 1 HHMPG HHBIN1 HH12A 5 10 15 20 25 HH cells Small Medium Large No. of CFC per 200 input cells HH MPG BIN1 12A Supplementary Figure 1: BIN1-transduced CTCL cells form smaller colonies. (A) Numbers of colony-forming cells (CFCs) based on the size of the colonies (small (<50), medium (50-500) and large (>500)) are indicated). (B) Representative images of the size and morphology of colonies in BIN1-transduced HH cells are shown. Data shown are mean ± SEM of measurements from at least three independent experiments. Supplementary Figure 1

Supplementary Figure 2 Cell cycle distribution (%) HutMPG HutBIN1 Hut12A 20 30 40 10 Sub-G1 G1 S G2 P= 0.05 P= 0.04 Cell cycle distribution (%) Supplementary Figure 2: Effects of BIN1 isoforms on cell-cycle distribution assessed using flow cytometric analysis. Control and BIN1-transduced Hut78 cells were analyzed using the PI cell-cycle assay. Each cell cycle is composed of G1, S, G2 phases, as well as a sub-G1 phase, which represents apoptotic cells. Cell-cycle distribution is indicated as a percentage, with three independent biological replicates. BIN1-transduced Hut78 cells had a significant increase in the sub-G1 population compared to controls, whereas there were no significant differences in G1, M, or G2 phases. Supplementary Figure 2

P = 0.009 P = 0.002 Supplementary Figure 3: Transcript levels of BIN1 in normal CD4+ T-cells versus primary Sezary cells and Hut78 cells. Transcript levels of BIN1 measured by qRT-PCR, normalized to GAPDH, from RNA samples extracted from normal CD4+ T-cells, primary Sezary cells and Hut78 cells. BIN1 expression was significantly downregulated in both Hut78 and primary Sezary cells compared to normal CD4+ T-cells . Supplementary Figure 3