Circular RNA EIF3I promotes papillary thyroid cancer progression by interacting with AUF1 to increase Cyclin D1 production

Circular RNAs (circRNAs) play an important role in regulating the development of human cancers through diverse biological functions. However, the exact molecular mechanisms underlying the role of circRNAs in papillary thyroid cancer (PTC) remain largely unknown. Here, we found that hsa_circ_0011385, designated as circular eukaryotic translation initiation factor 3 subunit I (circEIF3I), preferentially localized in the cytoplasm of PTC cells and was more stable than its linear counterpart, EIF3I. Gain- and loss-of-function studies indicated that circEIF3I promoted PTC progression by facilitating cell proliferation, cell cycle, cell migration, and invasion in vitro, as well as PTC cell proliferation in vivo. Mechanistically, circEIF3I interacted with AU-rich element (ARE) RNA-binding factor 1 (AUF1) in the cytoplasm of PTC cells, thus reducing the degradation of Cyclin D1 mRNA and increasing Cyclin D1 protein production, ultimately resulting in PTC progression. Collectively, our results demonstrate the vital role of circEIF3I in PTC progression, supporting its significance as a potential therapeutic target.

Automated summary

Circular RNAs (circRNAs) play a crucial role in human cancer development, including papillary thyroid cancer (PTC). The circRNA circEIF3I is found to promote PTC progression by enhancing cell proliferation, cycle, migration, invasion, and in vivo cell proliferation. Mechanistically, circEIF3I interacts with AUF1 to stabilize Cyclin D1 mRNA and increase Cyclin D1 protein production. These findings highlight the significance of circEIF3I as a therapeutic target for PTC.