YY1 induced hypoxic breast cancer-derived exosomal circ_000543 promotes proliferation and invasion of breast cancer cells / 中华内分泌外科杂志

ABSTRACT

Objective:To investigate the effects of circ_000543 derived from hypoxic exosomes on proliferation and invasion of breast cancer (BC) cells.Methods:Bioinformatic website was used to predict the abnormal expression of circ_000543 in BC tissue and the transcription factor that might regulate circ_000543. Double luciferase report experiment and ChIP assay were used to confirm the regulation relationship between YY1 and circ_000543. Exosomes were separated from normal BC cells and BC cells under hypoxic condition, and qRT-PCR was adopted to detect the expression of circ_000543 in exosomes. The expression of circ_000543 and YY1 in exosomes was intervened and the exosomes were cocultured with BC cells under normoxia. CCK8 and Transwell assay was used to detect the proliferation and invasive ability individually.Results:qRT-PCR experiment found that, compared with MCF-10A cells (1±0.11) and exosomes isolated from normoxic cells (1±0.10), circ_000543 expression was up-regulated in BC cells (1.59±0.13) and exosomes derived from cells under hypoxic condition (1.63±0.12) ( t=6.001, P=0.004; t=6.986, P=0.002). Exosomes derived from cells under hypoxic condition promoted proliferation and invasion of BC cells under normoxia. Inhibition of circ_000543 partially offset the effects of exosomes. YY1 induced the expression of circ_000543 in BC cells as a transcription factor. The expression of circ_000543 was inhibited when YY1 expression was down-regulated; at the same time, down-regulation of YY1 inhibited the effects of exosomes on proliferation and invasion of BC cells. Conclusion:The transcription factor YY1 promoted proliferation and invasion of BC cells by inducing hypoxic breast cancer-derived exosomal circ_000543.