Total RNA, including small RNA, was extracted and purified using the miRNeasy Mini Kit (QIAGEN Inc., Valencia, CA, USA) following the manufacturer's instructions. For miRNA analysis, TaqMan MicroRNA Reverse Transcription kit (Applied Biosystems) was first used to generate cDNA with the hairpin primers, which are specific to the mature miRNA and will not bind to the precursors. The expression levels of miR-125a-5p, miR-125b, and miR-205 were then measured by real-time PCR using TaqMan MicroRNA Assays (assay ID: 002198, 000449, 000509, respectively; Applied Biosystems) according to the manufacturer's protocol. RNU6B was used as an internal control to normalize all data using the TaqMan RNU6B Assay (assay ID: 001093; Applied Biosystems). RNU6B levels were unaffected by entinostat treatment. The relative miRNA levels were calculated using the comparative Ct method (ΔΔCt).