RP4010 inhibited cell proliferation in cultured human ESCC cell lines. (A) Cell viability with or without RP4010 treatment after 72 h were calculated by MTT assay in ESCC cells, i.e. KYSE-30, KYSE-70, KYSE-150 and KYSE-790. The relative cell numbers were normalized with samples with vehicle control. Cell viability after 24 h, 48 h and 72 h in KYSE-30 (B) and KYSE-150 (C) are examined. Data were collected from two independent experiments and triplicates each time, Mean ± SD.