Preliminary screening and analysis of metastasis-related lncRNA and co-expressed papillary thyroid carcinoma mRNA

Long non-coding RNA GHET1 promotes thyroid cancer cell proliferation and invasion

BACKGROUND

We aimed to evaluate the role of long non-coding RNA (LncRNA) gastric carcinoma proliferation-enhancing transcript 1 (GHET1) on thyroid cancer (TC) behavior in vitro.

METHODS

TC tissues and paired adjacent normal tissues were obtained after surgical excision from 43 patients with TC. The expression of LncRNA GHET1 was analyzed by real-time (RT) PCR. Human papillary thyroid cancer cell lines (TPC-1, BCPAP) were used to examine the role of LncRNA GHET1 in vitro. Cell proliferation was determined by CCK8 and cell colony formation assays. Transwell and wound-healing assays were used to detect the invasion and migration of thyroid cancer cells.

RESULTS

Our results showed that LncRNA GHET1 was significantly more upregulated in TC tissues than in adjacent normal tissues. LncRNA GHET1 was also increased in thyroid cancer cell lines compared to normal thyroid cell lines. The upregulation of LncRNA GHET1 was significantly associated with tumor invasion, gender, and lymph node metastasis in patients with thyroid cancer. The in vitro studies showed that silencing LncRNA GHET1 in BCPAP cells inhibited cell proliferation, cell invasion, and migration. Silencing of LncRNA GHETI also promoted the cell apoptotic rate, caused an increase in the cell population at the G0/G1 phase, and decreased the cell population at the S phase. In contrast, the overexpression of LncRNA GHET1 promoted cell proliferation, invasion, and migration, inhibited cell apoptosis, and increased cell population at the S phase in TPC cells.

CONCLUSIONS

LncRNA GHET1 dysregulation might be involved in the carcinogenesis of thyroid cancer. LncRNA GHET1 could be used as a potential molecular marker and molecular target for TC.

The Emerging Landscapes of Long Noncoding RNA in Thyroid Carcinoma: Biological Functions and Clinical Significance

Thyroid carcinoma (TC) is one of the most prevalent primary endocrine tumors, and its incidence is steadily and gradually increasing worldwide. Accumulating evidence has revealed the critical functions of long noncoding RNAs (lncRNAs) in the tumorigenesis and development of TC. Many TC-associated lncRNAs have been documented to be implicated in TC malignant behaviors, including abnormal cell proliferation, enhanced stem cell properties and aggressiveness, and resistance to therapeutics, through interaction with proteins, DNA, or RNA or encoding small peptides. Therefore, further elucidating the lncRNA dysregulation sheds additional insights into TC tumorigenesis and progression and opens new avenues for the early diagnosis and clinical therapy of TC. In this review, we summarize the abnormal expression of lncRNA in TC and the fundamental characteristics in TC tumorigenesis and development. Additionally, we introduce the potential prognostic and therapeutic significance of lncRNAs in TC.

hsa_circ_0001018 promotes papillary thyroid cancer by facilitating cell survival, invasion, G1/S cell cycle progression, and repressing cell apoptosis via crosstalk with miR-338-3p and SOX4

We identified a novel interactome, circ_0001018/miR-338-3p/SOX4, in papillary thyroid cancer (PTC), and we intended to confirm the regulatory relationship between the three and to study the effects of the three in PTC. The bioinformatics method was used to screen out the circular RNA and mRNA of interest. A cellular fractionation assay and fluorescence in situ hybridization (FISH) assay were conducted to prove that circ_0001018 and CCT4 (the host gene of circ_0001018) mRNA primarily localized in the cytoplasm of PTC cell lines. By qRT-PCR analysis, the expression of circ_0001018 and SOX4 mRNA was found upregulated while the expression of miR-338-3p was found downregulated in PTC tissues and cells. circ_0001018 silence significantly inhibited the tumor growth in xenografted nude mice. A series of cytological experiments such as a Cell Counting Kit-8 (CCK-8) assay, a 5-ethynyl-2′-deoxyuridine (EdU) assay, cell cycle profiling, wound healing, a transwell assay, and cell apoptosis were conducted and showed that circ_0001018 and SOX4 promoted cell proliferation, migration, and invasion, inhibited cell apoptosis, and reduced the cell cycle arrest at the G₁ phase in PTC cells. Compared with circ_0001018 and SOX4, miR-338-3p held the opposite function. The regulatory relationship between circ_0001018 and miR-338-3p, and between miR-338-3p and SOX4 mRNA, was validated using a luciferase reporter gene assay and/or RNA immunoprecipitation (RIP assay). Our findings showed that circ_0001018 acted as the tumor promoter via sponging miR-338-3p to elevate SOX4 expression level in PTC. Importantly, this novel circ_0001018/miR-338-3p/SOX4 axis has the potential to be considered as a therapy target for PTC.

IGFBP3 as an indicator of lymph node metastasis and unfavorable prognosis for papillary thyroid carcinoma

Lymph node metastasis (LNM) is a usual event in papillary thyroid carcinoma (PTC) patients, which usually leads to poor prognosis. However, the molecular mechanisms of LNM remain unclear. Thus, we aimed to screen the possible key genes in the progression of LNM in PTC patients and further validate their roles. The study involved two phases: a discovery phase and a validation one. In the former phase, the candidate genes were screened by using bioinformatics methods. In the latter one, the genes were firstly assessed in a cohort from the cancer genome atlas (TCGA) to evaluate the associations of their expressions with clinical features and the prognostic values, and then, they were assessed at protein levels by using an immunohistochemical assay. Consequently, IGHBP3 was selected as the candidate gene, which might be enriched in several metabolism-related pathways and cancer progression-related pathways. High expressions of IGHBP3 have an association with gender, advanced clinical stages, high T stages, and the presence of LNM. Survival analysis indicated that IGHBP3 may affect the prognosis of PTC patients. The use of a tissue chip confirmed the view that IGHBP3 might play a crucial role in the LNM of PTC. In conclusion, IGHBP3 might be involved in the development of LNM in PTC patients. IGHBP3 over-expression might be a novel indicator and a potential target for PTC therapy.

Immune-related key gene CLDN10 correlates with lymph node metastasis but predicts favorable prognosis in papillary thyroid carcinoma

The functions of immune cells in lymph node metastasis (LNM) have attracted considerable attention. This study aimed to screen the key immune-related and LNM-related genes in PTC. In the discovery phase, the immune-related genes in LNM were screened by using bioinformatics methods. In the validation phases, the association of the genes with LNM was first confirmed in a cohort from The Cancer Genome Atlas and a cohort based on a tissue chip. Then, the relationship of the genes with immune cell infiltration was further explored. Consequently, CLDN10 was identified, and its high expression was correlated with the presence of LNM in PTC but predicted a favorable prognosis. High CLDN10 expression was positively correlated with the infiltration of several immune cells, such as B cells, CD8+T cells, and macrophages. High CLDN10 expression may improve the outcomes of patients with PTC by increasing immune cell infiltration, although it might be associated with LNM. In conclusion, although CLDN1 might be correlated with LNM, it may also increase the infiltration of immune cells, including CD8+T cells and macrophages, and improve the clinical outcomes of patients with PTC. The effects of tumor purity and immune cell infiltration need to be considered in prognosis evaluation.