ABSTRACT
BACKGROUND: Anaplastic thyroid carcinoma (ATC) was a rare and extremely malignant endocrine cancer. Recently, dysregulation of circadian rhythm genes was demonstrated to play an essential role in tumor progression, while its exact role and mechanism in ATC remained poorly clear. METHODS: 4 ATC-related datasets were integrated to screen for differentially expressed circadian rhythm genes (DE-CRGs). Thereafter, Multiscale Embedded Gene Co-expression Network Analysis (MEGENA) and network enrichment analysis were conducted to investigate the dynamic characteristics of circadian rhythm genes. Next, Lasso-logistic model and immunohistochemistry were applied for determining the candidates. Finally, cell biological experiments and gene set enrichment analysis (GSEA) were used to confirm the roles of NPAS2 in ATC. RESULTS: 25 DE-CRGs were firstly identified in ATC. These DE-CRGs mainly regulated mitotic nuclear division, cytokinesis and DNA replication signals. Notably, NPAS2, CSNK1E, NAMPT, TYMS, SERPINE1, TOP2A, JUN, EGR3 and HEBP1 were identified as the dynamic signature in the malignant progression of ATC, which were confirmed by prognostic analysis. Furthermore, NPAS2 was found to be significantly up-regulated in ATC through clinical samples and cell experiments. Silencing NPAS2 effectively inhibited the proliferation, migration and invasion of ATC cells. GSEA showed that high expression of NPAS2 was mainly associated with cell cycle and focal adhesion, and silencing of NPAS2 suppressed these signals in our experiments. CONCLUSIONS: In summary, we found a dynamic 9-DE-CRGs signature in ATC. And the aberrant expression of NPAS2 drove the malignant phenotypes of ATC, which facilitated to deepen our understanding of the roles of circadian rhythm genes in ATC.
