Association between FACT levels and cell growth, sensitivity to curaxins, and tumor phenotype. (A) Colony formation of HT1080 cells transduced with the indicated shRNAs. Inset: Western blots show shRNA effects on target protein levels. Data are mean of three replicates ± SD. **P < 0.01; ***P < 0.001, t tests. (B) Increased cell sensitivity to curaxin, but not cisplatin, after FACT knockdown. Colonies formed by cells plated 72 hours after shRNA transduction and treated with CBLC137 (0.5 μM) or cisplatin (1 μg/ml) for 24 hours. The mean number of colonies relative to untreated cells transduced with the same shRNA is shown. **P < 0.01; ***P < 0.001, t tests. (C) Enrichment of cells with higher levels of SSRP1 during CBLC137 exposure. FACS detection of GFP-tagged SSRP1 expression in transduced HT1080 cells cultured in 0.3 μM CBLC137 for different time. (D) Quantification of data shown in (C). **P < 0.01; ***P < 0.001, t tests. (E) Western analysis of FACT subunit expression in total cell extracts from tissues of an MMTV-neu mouse with palpable tumors. The mouse had visible lung metastases (lane indicated “lung with mts”). (F) Western analysis of FACT subunit expression in different cultured human cell lines. See also fig. S5.