Exosome circ_0044516 promotes prostate cancer cell proliferation and metastasis as a potential biomarker.

Circular RNAs (circRNAs) are important regulators in cancer growth and progression. Exosomes carry various molecules including RNA, protein, and lipid from one cell to another cell. But the role of circRNAs from the exosomes from prostate cancer patients are not elucidated. In this study, circ_0044516 was found upregulated in prostate cancer and the roles and molecular mechanism of Hsa_circ_0044516 (circ_0044516) was investigated. Firstly, the exosomes of prostate cancer patients were collected for human circRNAs microarray to screen the circRNA expression profile. There were 35 significantly expressed circRNAs with more than fivefolds from microarray analysis. Circ_0044516 was verified to be significantly upregulated in the exosomes from prostate cancer patients and the cell lines. Further investigation demonstrated that circ_0044516 downregulation inhibited the proliferation and metastasis of prostate cancer cells. By bioinformatics and luciferase reporter assays, circ_0044516 was verified to downregulate miR-29a-3p expression and negatively related to miR-29a-3p expression levels in prostate cancer. In a summary, the study indicated that circ_0044516 played an important role in prostate cancer cell survival and metastasis, which suggested that an oncogenic role of circ_0044516 in prostate cancer.