Total RNAs from each sample were extracted using TRIzol® reagent (Vigorous Biotechnology), and then reverse transcribed using a cDNA Synthesis kit (Takara Biotechnology Co., Ltd.) at 37°C for 15 min and 85°C for 5 sec. A qPCR assay was then used to validate the expression levels of miR-574-5p, miR-468-3p, miR-32-3p and miR-672-5p and YAF2, which was performed on the ABI 7500 Fast Real-Time PCR system (Applied Biosystems; Thermo Fisher Scientific, Inc.). The RT-qPCR reaction was conducted in 20 µl reaction volumes containing cDNA, primers and SYBR Green Real-time PCR Master mix (Shanghai Yeasen Biotechnology Co., Ltd.). The following thermocycling conditions were used: Initial denaturation at 95°C for 5 min; followed by 40 cycles at 95°C for 10 sec, 60°C for 30 sec and 72°C for 30 sec. The 2−ΔΔCq method was used to access the relative RNA expression levels (21 (link),22 (link)). GAPDH and U6 were used as internal references, respectively. The primer sequences are listed in Table I.