Effects of a STAT3 inhibitor on the everolimus-induced cell growth inhibition in HaCaT, Caki-1, and HepG2 cells. HaCaT, Caki-1, and HepG2 cells were incubated in medium containing everolimus at the indicated concentrations for 48 h after pretreatment with 10 μM stattic or DMSO (a solvent of stattic) for 20 min. Cell viability was determined by WST-8 colorimetric assay. *p < 0.01 Student’s t test compared with control (DMSO). There was no significant difference in cell toxicity in the DMSO, stattic, and 0 μM everolimus conditions for each cell line.