CDCA8 Contributes to the Development and Progression of Thyroid Cancer through Regulating CDK1

Background: This study aims to reveal regulatory role of cell division cycle associated 8 (CDCA8) in thyroid cancer progression and metastasis. Methods: A series of experiments in vivo and in vitro were performed to explore the function of CDCA8 in thyroid cancer. Results: Immunohistochemical analysis showed that CDCA8 expression levels were upregulated in thyroid cancer tissues compared with normal tissues, and were statistically correlated with tumor stage. Results of in vitro loss-of-function assay showed that downregulation of endogenous expression of CDCA8 could significantly inhibit cell proliferation, colony formation, cell migration, and promote apoptosis. Thyroid cancer cells lacking CDCA8 expression also had reduced tumorigenicity in vivo. Further, results of preliminary mechanistic exploration showed that CDK1 may be a potential downstream molecule of CDCA8 in regulating thyroid cancer progression. We subsequently confirmed that CDK1 itself exerted a significant regulatory function in thyroid cancer by loss- and gain-of-function experiments. Moreover, overexpression of CDK1 could weaken the tumor suppressive effect caused by CDCA8 knockdown. Conclusions: CDCA8 functions as an oncogene in thyroid cancer, and CDCA8 knockdown suppresses cancer development in vitro and in vivo. Additionally, CDK1 was further identified as a potential target of CDCA8 in thyroid cancer.