Hsa_circ_0002473 inhibits GH3 cell proliferation and GH secretion as a competitive endogenous RNA for has-miR-4645-3p.

Growth hormone deficiency (GHD) diagnosis still lacks a gold standard or ideal diagnostic marker. Unlike other epigenetic mechanisms, non-coding RNAs regulate post-transcriptional levels. The information on non-coding RNAs in the field of GHD is limited. Therefore, this study aimed to explore the role of hsa_circ_0002473 as a competitive endogenous RNA for has-miR-4645-3p in attenuating the inhibitory effect of has-miR-4645-3p on SSTR2. In this study, we screened three significantly expressed circular RNAs (circRNAs) in five children with GHD, and selected the highest expressed hsa_circ_0002473 as the study object, and screened has-miR-4645-3p, which is the most likely to bind to hsa_circ_0002473, according to the microRNA (miRNA)-circRNA regulatory network, to study the role and mechanism of has-miR-4645-3p as a competitive endogenous RNA of has-miR-4645-3p on GH3 cells. Somatostatin receptor 2 (SSTR2) inhibits GH3 cell proliferation, and miRNA binding to SSTR2 inhibits the latter expression. Both bioinformatics and dual-luciferase reporter analyses showed targeting relationships between hsa_circ_0002473 and has-miR-4645-3p and between has-miR-4645-3p and SSTR2. We constructed the hsa_circ_0002473/has-miR-4645-3p axis and transfected it into GH3 cells and found that overexpression of hsa_circ_0002473 inhibited the proliferation and growth hormone (GH) secretion of GH3 cells, and that hsa-miR-4645-3p promoted the proliferation and GH secretion of GH3 cells by targeting SSTR2. Co-culture revealed that the inhibitory effect of hsa_circ_0002473 was reversed by has-miR-4645-3p. In conclusion, our findings suggest that hsa_circ_0002473 can act as a competitive endogenous RNA for has-miR-4645-3p to regulate GH3 cell proliferation and secretion by targeting SSTR2.