FIGURE 1 from Targeting the Clear Cell Sarcoma Oncogenic Driver Fusion Gene EWSR1::ATF1 by HDAC Inhibition

Vorinostat treatment inhibits CCS cell growth in vitro and in vivo. A, MP-CCS-SY, SU-CCS1, Hewga-CCS, KAS, and NHDF cells were incubated with 0–30 μmol/L vorinostat for 48 hours, and the viable number of cells were estimated via a WST-8 assay (n = 3). The calculated IC50 values are shown in Table 1. B, Four CCS cell lines were treated with 0.3 and 3 μmol/L vorinostat or vehicle for 48 hours, stained with PI, and analyzed for cell-cycle stage using flow cytometry. C, Four CCS cell lines were treated with 0.3 to 10 μmol/L vorinostat or vehicle for 24 hours, and the protein expression levels of the apoptosis markers cleaved caspase-3 was detected using Western blotting. D and E, SU-CCS1 and Hewga-CCS cells were engrafted in nude mice, which were treated with 50 mg/kg vorinostat or vehicle via intraperitoneal administration (5 mice/group). Volume (D) and weight (E) of SU-CCS1 and Hewga-CCS tumors during treatment are shown (n = 5). Data in A, D, and E are means ± SDs. *, P < 0.05; **, P < 0.01 (Student t test).