[en] Dysregulation of cell proliferation and death is considered the foundation of the malignant biological characteristics of cancer. In this study, we conducted a comprehensive analysis of a massively parallel whole transcriptome resequencing of paired papillary thyroid cancer and normal thyroid tissues from 19 patients. In addition, we found that LRP4, a member of the low-density lipoprotein receptor-related protein family, is significantly overexpressed in thyroid carcinoma. We demonstrated through quantitative real-time polymerase chain reaction (qRT-PCR) that LRP4 is upregulated in papillary thyroid cancer (PTC) tissues. This observation was also consistent with data analyzed from The Cancer Genome Atlas (TCGA) cohort. Thus, the biological role of LRP4 in the thyroid cancer in the present study was investigated using the PTC cell lines TPC1, BCPAP and KTC-1. In these cell lines, the mRNA level of LRP4 was higher than normal thyroid cancer cell named HTORI3. In vitro experiments demonstrated that LRP4 downregulation significantly inhibited the colony formation, proliferation, migration, and invasion of the three PTC cell lines. Knockdown of LRP4 by small interfering RNA (siRNA) in those cell lines decreased the protein expression of N-cadherin, Enhancer of zeste homolog 2 (EZH2), and Zinc finger E-box-binding home-box 1 (ZEB1). Furthermore, LRP4 knockdown significantly reduced the levels of phosphorylated PI3K in the PTC cell lines. In conclusion, the present study indicated that LRP4 is a gene associated with PTC and might become a potential therapeutic target.

[en] In decades, a lot of long non-coding RNAs (LncRNAs) have been proven to exert influences on tumorigenesis in vitro and in vivo. Many lncRNAs have been reported as effective therapeutic targets and biomarkers in various cancers. However, whether LncRNAs are associated with the progression of PTC remains largely unknown. In this study, we measured the expression of CCND2-AS1 in PTC cell lines by quantitative real-time polymerase chain reaction (qRT-PCR).We found that CCND2-AS1 expression was significantly over-expressed in PTC cell lines compared to normal thyroid epithelial cells. Gain-and loss-of-function experiments were performed to investigate the role of CCND2-AS1 in PTC cells. In vitro experiments, we proved that CCND2-AS1 knockdown in TPC1 significantly suppressed cell proliferation, migration, and invasion, while CCND2-AS1 overexpression in BCPAP had the opposite effects. Meanwhile, we also found that CCND2-AS1 could regulate N-cadherin and Vimentin expression, which may influence invasion and migration. Our findings indicate that the lncRNA CCND2-AS1 is a gene associated with PTC and might become a potential therapeutic target.