Proliferation Of Thyroid Carcinoma Cells Research Articles

Long non-coding RNA DUXAP8 promotes the cell proliferation, migration, and invasion of papillary thyroid carcinoma via miR-223-3p mediated regulation of CXCR4

ABSTRACT Papillary thyroid carcinoma (PTC) is a differentiated type of thyroid malignancy with a high incidence. Long non-coding RNA (lncRNA) DUXAP8 has been reported to participate in the proliferation, migration, and invasion of several cancer types. However, its association with PTC has not yet been reported. The current study aimed to investigate the role of DUXAP8 in PTC and revealed the underlying mechanisms. The expression of DUXAP8 was knocked down in two PTC cell lines and the effects of DUXAP8 on the PTC biological behavior were examined by cell counting kit-8 (CCK-8), wound healing, and transwell invasion assays. Luciferase reporter assay was used to detect the binding activity between miR-223-3p and DUXAP8. We found that knockdown of DUXAP8 inhibited the proliferation, migration, and invasion of PTC cells. DUXAP8 could sponge miR-223-3p through the specific binding site. CXCR4 was a target of miR-223-3p. The malignant phenotypes of the PTC cells were suppressed by the over-expression of miR-223-3p. Moreover, miR-223-3p inhibition or CXCR4 over-expression partly restored the proliferation, migration, and invasion activities of DUXAP8-downregulated PTC cells. The results evidenced that DUXAP8 acted as an oncogene in PTC, these effects seemed to partly dependent on the miR-223-3p/CXCR4 axis.

Suppression of long noncoding RNA LINC00324 restricts cell proliferation and invasion of papillary thyroid carcinoma through downregulation of TRIM29 via upregulating microRNA-195-5p.

Long noncoding RNAs (lncRNAs) are identified as novel regulators of carcinogenesis. To date, the precise functions of lncRNAs in papillary thyroid carcinoma (PTC) remains poorly understood. The purposes of this work were to explore the potential relevance of lncRNA 00324 (LINC00324) in PTC. Levels of LINC00324 were markedly up-regulated in PTC. Silencing of LINC00324 significantly repressed the proliferation and invasion of PTC cells. LINC00324 was documented as a sponge of microRNA-195-5p (miR-195-5p). Decreased levels of miR-195-5p were detected in PTC. The up-regulation of miR-195-5p suppressed PTC cellular proliferation and invasion. Suppression of miR-195-5p partially reversed the LINC00324-knockdown-mediated effects in PTC cells. We identified tripartite motif-containing 29 (TRIM29) as a target gene of miR-195-5p. TRIM29 overexpression partially reversed the LINC00324-knockdown- or miR-195-5p-overexpression-mediated effects in PTC cells. In short, this work demonstrates that LINC00324 knockdown inhibits the proliferation and invasion of PTC cells by decreasing TRIM29 expression via up-regulating miR-195-5p expression.

M2-like tumor-associated macrophages-secreted Wnt1 and Wnt3a promotes dedifferentiation and metastasis via activating β-catenin pathway in thyroid cancer.

Thyroid carcinoma (TC) has been a global issue for its rapid increasing incidence worldwide. Although most TC was not so aggressive with a good prognosis, treatment against anaplastic TC was relatively limited and the mechanisms are not well elucidated yet. TC cell lines (IHH4 and TPC-1) were used. Flow cytometry was used to identify the surface marker of M2-like tumor-associated macrophages (TAMs) from cell culture. Quantitative real-time polymerase chain reaction, western blot analysis, immunostaining, and immunohistochemistry were used to detect the expression of Wnt1, Wnt3a, components of Wnt/β-catenin pathway, and proliferation/epithelial-mesenchymal transition (EMT)-related proteins. Alkaline phosphatase activity assay, colony formation assay, and transwell assay were used to examine the roles of Wnt1, Wnt3a, and β-catenin pathway in cell dedifferentiation, proliferation, migration, and invasion of TC cells, respectively. Subcutaneous tumor growth was monitored in nude mice. Coculture with M2-like TAMs facilitated dedifferentiation, proliferation, migration, and invasion in TC cells. EMT and proliferation-related proteins were also promoted in cocultured TC cells. The level of Wnt1 and Wnt3a was increased in the coculture system. Block of Wnt1 or Wnt3a suppressed malignant behaviors in cocultured tumor cells. Furthermore, Wnt1 or Wnt3a knockdown inhibited Wnt/β-catenin signaling pathway, and suppressed EMT and proliferation-related signals in cocultured tumor cells. Knockdown of Wnt1 or Wnt3a inhibited tumor growth in xenograft model. M2-like TAMs promoted dedifferentiation, proliferation, and metastasis of TC by Wnt1 and Wnt3a secretion and ensuing β-catenin activation.

CSN5 Promotes Carcinogenesis of Thyroid Carcinoma Cells Through ANGPTL2.

COP9 signalosome subunit 5 (CSN5) plays a key role in carcinogenesis of multiple cancers and contributes to the stabilization of target proteins through deubiquitylation. However, the underlying role of CSN5 in thyroid carcinoma has not been reported. In this research, our data showed that CSN5 was overexpressed in thyroid carcinoma tissues compared with paracancerous tissues. Furthermore, a series of gain/loss functional assays were performed to demonstrate the role of CSN5 in facilitating thyroid carcinoma cell proliferation and metastasis. Additionally, we found there was a positive correlation between CSN5 and angiopoietin-like protein 2 (ANGPTL2) protein levels in thyroid carcinoma tissues and that CSN5 promoted thyroid carcinoma cell proliferation and metastasis through ANGPTL2. We also identified the underlying mechanism that CSN5 elevated ANGPTL2 protein level by directly binding it, decreasing its ubiquitination and degradation. Overall, our results highlight the significance of CSN5 in promoting thyroid carcinoma carcinogenesis and implicate CSN5 as a promising candidate for thyroid carcinoma treatment.

Downregulation of lncRNA ZFAS1 inhibits the hallmarks of thyroid carcinoma via the regulation of miR‑302‑3p on cyclin D1.

At present, treatment options for thyroid carcinoma remain limited. The present study aimed to investigate the role of ZFAS1 in various major hallmarks of cancer and the underlying mechanisms in thyroid carcinoma cells. The interactions between long non-coding RNAs (lncRNAs), microRNAs (miRs) and target genes were predicted by bioinformatics and confirmed by performing dual-luciferase assays. The mRNA and protein expressions were determined by reverse transcription-quantitative PCR and western blotting. Cell invasion, migration, and viability were evaluated via Transwell, wound-healing and Cell Counting Kit-8 assays, respectively. The results demonstrated that lncRNA ZFAS1 expression was upregulated in thyroid carcinoma tissues, TT and SW579 cells, and was associated with the proliferation of these two cell lines. Notably, downregulation ZFAS1 reduced migration and invasion, and reversed the promotive effects of miR-302a-3p inhibitor on the proliferation, migration and invasion of TT and SW579 cells. Moreover, cyclin D1 (CCND1) is targeted by miR-302a-3p, and was regulated by ZFAS1. In addition, the downregulation of ZFAS1 not only reversed the promotive effects of miR-302a-3p inhibitor on CCND1 expression and the epithelial-mesenchymal transition (EMT) of TT and SW579 cells, but also targeted and increased the expression of miR-302a-3p, and further reduced the expression of CCND1, resulting in suppression of the proliferation, migration, invasion and EMT of thyroid carcinoma cells.

Long Non-Coding RNA LUCAT1 Promotes Progression of Thyroid Carcinoma by Reinforcing ADAM10 Expression Through Sequestering microRNA-493.

BackgroundLong non-coding RNA (lncRNA) LUCAT1 has recently been recognized as an oncogene in several malignancies. This study was launched to probe its role in thyroid carcinoma (TC) development and the implicated molecules.MethodsLUCAT1 expression in TC cell lines and in normal thyroid follicular epithelial cell line Nthy-ori3-1 was determined by RT-qPCR. Binding relationships between LUCAT1 and microRNA (miR)-493, and between miR-493 and a disintegrin and metalloproteinase-10 (ADAM10) were predicted on a bioinformatics system and then validated through luciferase reporter gene assays. Expression of miR-493 and ADAM10 in TC cells was determined. Gain- and loss-of functions of LUCAT1, miR-493 and ADAM10 were performed to explore their influences on the behaviors of TC cells. Xenograft tumors were induced in nude mice for in vivo studies.ResultsLUCAT1 and ADAM10 were highly expressed, while miR-493 was poorly expressed in TC cell lines. LUCAT1 served as a miR-493 sponge to upregulate ADAM10 expression. Silencing of LUCAT1 discouraged proliferation, invasion, and migration but triggered apoptosis of TC cells. By contrast, these changes were abrogated by further miR-493 inhibition or ADAM10 upregulation. The in vitro experiment results were reproduced in vivo. In addition, miR-493 inhibition or ADAM10 overexpression was found to increase the phosphorylation of STAT3 in cells.ConclusionThis study evidenced that LUCAT1 increases ADAM10 expression through sequestering miR-493, leading to JAK-STAT activation and TC cell growth and metastasis. LUCAT1 and ADAM10 may serve as therapeutic targets for TC treatment.

USP7 promotes proliferation of papillary thyroid carcinoma cells through TBX3-mediated p57KIP2 repression

Ubiquitin-specific protease 7 (USP7/HAUSP) is known to regulate multiple cellular phenomena, including cell cycle progression and proliferation, and is involved in binding and stabilizing specific target proteins through deubiquitylation. However, the detailed role of USP7 in papillary thyroid carcinoma (PTC) remains to be investigated. In this study, our results showed that USP7 was upregulated in PTC tissues compared with adjacent nontumour tissues. Consistently, a series of gain/loss functional assays in vivo and in vitro demonstrated the role of USP7 in promoting PTC cell proliferation. Furthermore, we showed that there was a negative correlation between USP7 and the CDK inhibitor p57KIP2 expression in PTC tissues and that USP7 facilitated PTC cell proliferation by inhibiting p57KIP2. Mechanistically, USP7 inhibited p57KIP2 expression by modulating TBX3, directly binding to TBX3, and decreasing its ubiquitination and degradation. Our findings demonstrated that USP7 played a critical oncogenic role in PTC tumorigenesis, suggesting that USP7 might act as a prognostic and therapeutic target for PTC progression.

Circ_0000144 facilitates the progression of thyroid cancer via the miR‐217/AKT3 pathway

Thyroid carcinoma (TC) is the most common malignancy of the endocrine system. Circular RNA (circRNA) is vital in the regulation of tumor progression. Circ_0000144 serves as a novel oncogenic circRNA, and miR-217 is reported to inhibit the malignant phenotypes of cancer cells by targeting AKT3 in TC. The present study aimed to explore the regulatory mechanism of circ_0000144 and miR-217 in the progression of TC. Circ_0000144 expression in 32 pairs of TC tissues and different TC cell lines (including BCPAP, K1, H7H83, and TPC-1) was detected by employing a quantitative real-time polymerase chain reaction (qRT-PCR). Circ_0000144 small interfering RNA was used to establish loss-of-function models. Cell counting kit-8 (CCK-8), BrdU (5-bromo-2'-deoxyuridine) and transwell assays were utilized to verify the effects of circ_0000144 on TC cell proliferation, migration and invasion, respectively. Bioinformatics, western blotting, a luciferase reporter experiment and qRT-PCR were employed to confirm the relationships among circ_0000144, miR-217 and AKT3. Circ_0000144 expression was remarkably elevated in TC tissues (p<0.001) and TC cell lines. The elevation of circ_0000144 expression was markedly linked to tumor size (p=0.015), TNM stage (p=0.025) and lymph node metastasis (p=0.017) of the patients. Functional studies showed that knocking down circ_0000144 repressed the malignancy of TC cells. Furthermore, miR-217 was identified as a downstream target of circ_0000144; inhibition of miR-217 could reverse the effects induced by circ_0000144 knockdown. Moreover, circ_0000144 could regulate AKT3 expression by suppressing miR-217 expression. Circ_0000144 exerts a cancer-promoting effect on TC cells via the miR-217/AKT3 pathway.

Mesenchymal stem cells-originated exosomal microRNA-152 impairs proliferation, invasion and migration of thyroid carcinoma cells by interacting with DPP4.

Thyroid carcinoma (THCA) is the most prevalent tumor in the endocrine system with an increasing incidence. Recent studies have underscored the function of microRNAs (miRNAs) in THCA. Nevertheless, knowledge regarding the effects of exosomal miRNAs in THCA is still limited. This report intended to probe the regulatory effects of exosomal miR-152 on THCA and the underlying mechanism. The expression profile of miR-152 was studied in clinical samples as well as B-CPAP and TPC-1 cells. Transwell, CCK-8, and flow cytometric assays were performed to investigate the roles of miR-152 on invasion, migration, proliferation, and apoptosis in B-CPAP and TPC-1 cells. The putative target of miR-152 was predicted using the bioinformatic analysis, and the targeting relationship was confirmed verified subsequently. Afterward, exosomes were isolated from bone marrow mesenchymal stem cells (BM-MSCs) and co-cultured with B-CPAP and TPC-1 cells to explore the function of exosomal miR-152 on THCA cells. miR-152 was reduced in THCA tissues and cells. Restoration of miR-152 inhibited proliferation, invasion and migration of B-CPAP and TPC-1 cells, but promoted cell apoptosis. Dipeptidyl dipeptidase 4 (DPP4), a target of miR-152, was found to promote THCA cell invasion and migration. miR-152 ferried by BM-MSCs-derived exosomes repressed THCA cell invasion and migration, and pcDNA-DPP4 weakened the repression effect. Exosomal miR-152 inhibited proliferation, migration and invasion of THCA cells by binding with DPP4, which may represent a novel target for the treatment of THCA.

Hsa-miR-195-5p inhibits cell proliferation of human thyroid carcinoma cells via modulation of p21/cyclin D1 axis.

BackgroundBased on existing evidence, microRNAs (miRs) are gene regulators that undertake key functions in the oncogenesis and tumor progression of every single human malignant disease, such as thyroid carcinoma (TC). Previous clinical findings showed that expression of miR-195 is down-regulated in TC, which implies that miR-195 may be practically involved in TC pathogenesis. Nevertheless, the function of hsa-miR-195-5p in TC is still largely unclear. Herein, we detected the conceivable involvement of hsa-miR-195-5p in TC cell proliferation.MethodsReal time PCR examination was performed to assess the expression level of hsa-miR-195-5p in TC cell lines TPC-1 and B-CPAP. TPC-1 cells were transfected with either hsa-miR-195-5p mimics or hsa-miR-195-5p inhibitor. After confirmation of transfection efficiency, the effect of hsa-miR-195-5p on proliferation and cell cycle of TPC-1 cells was assessed. The expression of cyclin D1 and p21 was simultaneously detected by western blotting. Moreover, targetScan 6.2 was used to predict hsa-miR-195-5p target genes. Subsequently, luciferase reporter was performed to examine whether there is a possible binding of hsa-miR-195-5p to 3’-UTR of cyclin D1 mRNA. Furthermore, cyclin D1 mRNA and protein levels were measured to check whether hsa-miR-195-5p exerts its function at the post-transcriptional level. In addition, to explore the function of cyclin D1 in TPC-1 cells overexpressing hsa-miR-195-5p, cyclin D1 siRNA was used to silence the expression of cyclin D1 in TPC-1 cells overexpressing hsa-miR-195-5p.ResultsWe quantified the expression of hsa-miR-195-5p in TC cells and normal thyroid cells and found a remarkable decrease in hsa-miR-195-5p expression in TC cells. Over-expression of hsa-miR-195-5p obviously resulted in downgraded proliferation of TC cells. Moreover, hsa-miR-195-5p caused cell arrest at the GO/G1 phase. Further in silico analyses and the dual-luciferase reporter assay confirmed that 3’-UTR of cyclin D1 is a direct target of hsa-miR-195-5p. Western blot analysis uncovered that hsa-miR-195-5p over-expression led to decreased levels of cyclin D1 and p21. In mechanistic analyses, we found that silencing of cyclin D1 reversed the inhibitory effect of hsa-miR-195-5p on the proliferation of TC cells, which indicates that hsa-miR-195-5p suppresses TC cell proliferation by adversely regulating cyclin D1.ConclusionsWe concluded that hsa-miR-195-5p is a candidate tumor-suppressor miRNA in TC and that the hsa-miR-195-5p/p21/cyclin D1 pathway could be a potential therapeutic target for TC.

Mechanism of RET gene mediated EGFR signaling pathway on epithelial-mesenchymal transition, proliferation and apoptosis of papillary thyroid carcinoma cells.

To explore the mechanism of RET gene mediated EGFR signaling pathway on the epithelial-mesenchymal transition (EMT), proliferation and apoptosis of papillary thyroid carcinoma (PTC) cells. PTC TPC-1 cells and human normal thyroid follicular epithelial cells Nthy-ori 3-1 were collected to identify the expression of RET in PTC. Seven groups were divided according to different transfection protocols, including blank group, negative control group, si-RET group, oe-RET group, AG-490 group, NSC 228155 group, and si-RET + NSC 228155 group. After transfection, qRT-PCR was used to identify whether the transfection was successful or not. qRT-PCR and Western blot were performed to detect the mRNA and protein expressions of RET, EGFR signaling pathway related genes, and EMT related genes. Cell migration, invasion, proliferation and apoptosis abilities were further detected by CCK8, cell scratch, transwell and flow cytometry assays, respectively. RET gene was highly expressed in PTC cells (p<0.05). Compared with blank group, oe-RET group and NSC 228155 group had activated EGFR signaling pathway manifesting in the increased expression of EGFR, p-Src, p-FAK, accelerated EMT showing in the increased expression of N-cadherin and Vimentin expression, but decreased E-cadherin expression, increased cell migration, invasion and proliferation, while decreased apoptosis (all p<0.05); si-RET group and AG-490 group had inhibited activation of EGFR signaling pathway, suppressed EMT, decreased cell migration, invasion and proliferation, while increased apoptosis (all p<0.05); while no evident difference was found in si-RET + NSC 228155 group (all p>0.05). Meanwhile, compared with si-RET group, si-RET + NSC 228155 group showed activated EGFR signaling pathway, accelerated EMT, increased abilities of cell migration, invasion and proliferation, while decreased apoptosis (all p<0.05). RET gene is highly expressed in PTC acting as an oncogene. Silencing RET gene expression may inhibit the invasion and promote the apoptosis of PTC cells by inhibiting the activation of EGFR signaling pathway and mediating the process of EMT. It suggests that RET may offer the possibility of a promising therapeutic target for the treatment of PTC on the basis of the explored mechanism.

Downregulation of miR-146b-5p via iodine involvement repressed papillary thyroid carcinoma cell proliferation.

miR-146b-5p is overexpressed in papillary thyroid carcinoma (PTC) and is thought to be a related diagnostic marker. Previous studies have indicated the effects of iodine on oncogenic activation. However, the effect of iodine on the proliferation of PTC cells and the associated underlying mechanisms remain unclear. We found that miR-146b-5p was downregulated and smad4 was upregulated in patients exposed to high iodine concentration by in situ hybridisation (ISH) and immunohistochemical (IHC). NaI (10-3 M) treatment downregulated miR-146b-5p and upregulated Smad4 in PTC cell lines. Luciferase assay was used to confirm that Smad4 is a target of miR-146b-5p. Furthermore, MTT assay and cell cycle analysis indicated that 10-3 M NaI suppressed cell proliferation and caused G0/G1 phase arrest. Real-time PCR and Western blotting demonstrated that 10-3 M NaI increased p21, p27, and p57 levels and reduced cyclin D1 levels in PTC cells. Our findings suggest that 10-3 M NaI increases Smad4 levels through repression of miR-146b-5p expression, curbing the proliferation in PTC.

MiR-744–5p mediates lncRNA HOTTIP to regulate the proliferation and apoptosis of papillary thyroid carcinoma cells

Papillary thyroid carcinoma (PTC) is the most common malignancy in thyroid. miR-744–5p plays an efficient role in various cancers, but its role in PTC remains unknown. In this work, we aimed to explore the function of miR-744–5p and the mechanism by which miR-744–5p acted in PTC. We observed that miR-744–5p expression was significantly declined in PTC tissues and cell lines. The high level of miR-744–5p is significantly associated with a better clinical picture of PTC patients. Overexpression of miR-744–5p inhibited the proliferation, arrested the cell cycle, and promoted the apoptosis in PTC cells. Oppositely, down-regulation of miR-744–5p reversed the above tendencies. We also found that miR-744–5p down-regulated its downstream genes c-myc and attenuated cell proliferation induced by c-myc. Long non-coding RNA (lncRNA) HOTTIP was found to be up-regulated and to act as an oncogene in PTC. In this study, miR-744–5p bound to HOTTIP and was negatively regulated by HOTTIP. In conclusion, miR-744-5p acts as a tumor suppressor to inhibit proliferation and promotes the apoptosis of PTC cells via targeting c-myc. Moreover, miR-744-5p expression interferes with lncRNA HOTTIP ability to promote proliferation and downregulate apoptosis in papillary thyroid carcinoma.

Up-regulated ANP32E promotes the thyroid carcinoma cell proliferation and migration via activating AKT/mTOR/HK2-mediated glycolysis.

Thyroid cancer (THCA) is one of the most common endocrine tumors and keeps rapidly increasing worldwide. Acidic nuclear phosphoprotein 32 family member E (ANP32E) is a H2A.Z histone chaperone that regulates the expression of various genes. It has been shown that ANP32E promotes breast cancer development, whereas its role in THCA remains unknown. In this study, we found that ANP32E was significantly overexpressed in THCA tissues. Down-regulation of ANP32E inhibited the growth, cell cycle progression, DNA synthesis, glycolysis, migration and increased apoptosis in K1 and TPC-1 cells. Opposite results were observed in ANP32E-overexpressing THCA cells. At the molecular level, ANP32E up-regulated MMP9 and MMP13, and activated AKT/mTOR/HK2 signaling in THCA cells. Positive correlation between ANP32E and HK2 was found in THCA tissues. Importantly, silencing of HK2 repressed glycolysis. Inhibition of AKT/mTOR reduced cell proliferation, cell cycle progression and migration in THCA cells. Our findings suggest that ANP32E promotes THCA cell proliferation and migration via potentiating AKT/mTOR/HK2-mediated glycolysis.

Knockdown of Thymidine Kinase 1 Suppresses Cell Proliferation, Invasion, Migration, and Epithelial-Mesenchymal Transition in Thyroid Carcinoma Cells.

Patients with advanced thyroid carcinoma have poor prognosis with low overall survival. Unfortunately, the underlying mechanisms of thyroid carcinoma progression remain unclear. The elevated expression of thymidine kinase 1 (TK1) has been implicated in the progression of thyroid carcinoma, while the role of TK1 in thyroid carcinoma progression has not been explored. The present study aimed to determine the role TK1 in the progression of thyroid cancer and to explore the underlying molecular mechanisms. In this study, it was found that serum TK1 levels were markedly increased in the patients with thyroid nodules. Further online data mining showed that TK1 expression was upregulated in thyroid carcinoma tissues, and higher expression of TK1 was correlated with shorter disease-free survival of patients with thyroid carcinoma. Silencing of TK1 suppressed cell proliferation, invasion, migration, and epithelial–mesenchymal transition, and also induced cell apoptosis in the thyroid carcinoma cell lines. Animal studies showed that TK1 knockdown inhibited in vivo tumor growth of thyroid carcinoma cells. Importantly, miR-34a-5p was found to be downregulated in the thyroid carcinoma cells. Furthermore, miR-34a-5p targeted the 3′ untranslated region of TK1 and suppressed the expression of TK1 in thyroid carcinoma cell lines. In summary, first, these results demonstrated the upregulation of TK1 in thyroid nodules and thyroid carcinoma tissues; second, TK1 promoted thyroid carcinoma cell proliferation, invasion, and migration; lastly, TK1 was negatively regulated by miR-34a-5p. Our study may provide novel insights into the role of TK1 in regulating thyroid carcinoma progression.

Downregulating integrin subunit alpha 7 (ITGA7) promotes proliferation, invasion, and migration of papillary thyroid carcinoma cells through regulating epithelial-to-mesenchymal transition

Thyroid cancer is one of the common malignancies of the endocrine system and the number of thyroid cancer cases is increasing constantly. Significant work has focused on the molecular mechanisms of thyroid cancer, but many mechanisms remain undiscovered. In this study, we employed a comprehensive analysis of whole-transcriptome resequencing derived from paired papillary thyroid cancer (PTC) and normal thyroid tissues. We performed a massive parallel whole-transcriptome resequencing of matched PTC and normal thyroid tissues in 19 patients and found that integrin subunit alpha 7 (ITGA7) was downregulated in thyroid tumor tissues, but the function of ITGA7 in this cancer is still unclear. We also discovered that ITGA7 gene in thyroid cancer tissues was downregulated compared to paired adjacent non-tumor tissues by real-time quantitative polymerase chain reaction. After transfection with small interfering RNA to knock down ITGA7, the abilities of colony formation, proliferation, migration, and invasion were enhanced in PTC cell lines (TPC1 and KTC-1). Meanwhile, ITGA7 knockdown decreased apoptotic cell death in thyroid cells but promoted the expressions of N-cadherin and vimentin and decreased E-cadherin expression by epithelial-to-mesenchymal transition, which may induce invasion and migration. In conclusion, these results indicated that ITGA7 is involved in the progress of PTC and might act as a tumor suppressor gene.

Effect of miR‑449a‑mediated Notch signaling pathway on the proliferation, apoptosis and invasion of papillary thyroid carcinoma cells.

The present study aimed to investigate the effect of miR-449a-mediated Notch signaling pathway on the proliferation, apoptosis and invasion of papillary thyroid carcinoma cells. Human papillary thyroid carcinoma cell line TPC-1 was selected, and cells were grouped and transfected: Control group (without any treatment), negative control (NC) group (transfection with NC plasmid), miR-449a mimic group (transfection with miR-449a mimic), miR-449a inhibitor group (transfection with miR-449a inhibitor), DAPT group (addition of γ-secretase inhibitor DAPT to inhibit the Notch signaling pathway), and miR-449a inhibitor + DAPT group (transfection with miR-449a inhibitor and addition of DAPT). The target relationship between miR-449a and Notch1 was detected by dual-luciferase reporter assay. qRT-PCR and western blotting were used to assess the expression of miR-449a, Notch1 and Jagged1 in cells. Cell proliferation was detected using EdU; the cell cycle and apoptosis were detected by flow cytometry; cell invasion ability was detected by Transwell assay. PCNA, MMP-2, MMP-9, Bcl-2 and Bax mRNA and protein expression were assessed by qRT-PCR and western blotting. The results revealed that miR-449a negatively regulated Notch1. Compared with the control group, there was significantly increased miR-449a expression in the miR-449a mimic group, and there was significantly decreased expression of Notch1, Jagged1, PCNA, MMP-2, MMP-9 and Bcl-2, increased Bax, reduced cell proliferation, increased G1-phase cell fraction, decreased S-phase cell fraction, an increased apoptosis rate, and decreased invasion ability in the miR-449a mimic group and DAPT group (all P<0.05). However, the results in the miR-449a inhibitor group were the opposite of those in miR-449a mimic group (all P<0.05). There was no significant difference in cell proliferation, apoptosis and invasion in the NC group and miR-449a inhibitor + DAPT group compared to the control group (all P>0.05). miR-449a overexpression can inhibit Notch signaling pathway, thereby inhibiting the proliferation and invasion of papillary thyroid carcinoma cells and promoting cell apoptosis.

MicroRNA-92b suppresses proliferation of papillary thyroid cancer cells by regulating ilent information regulator 1 gene expression

Objective To investigate the regulating effects of microRNA (miRNA, miR)-122 on the expression of ilent information regulator 1 (SIRT1), and the proliferation abilities of papillary thyroid cancer cells. Methods Real-time quantitative polymerase chain reaction (Real-time PCR) was used to observe the expression of miR-122 in papillary thyroid carcinoma and adjacent tissues and to analyze its correlation with SIRT1 expression. After transfecting miR-122 mimics into human papillary thyroid carcinoma cell line TPC-1, the dual luciferase reporter gene assay was used to observe the regulation of miR-122 on SIRT1 gene. The effect of miR-122 on the proliferation of thyroid cancer cells was observed by CCK-8 assay. At the same time, the overexpressed SIRT1 plasmid was co-transfected into TPC-1 cells, and then the effect of miR-122 and SIRT1 expression on the proliferation of papillary thyroid carcinoma cells was detected by CCK-8 assay. Analysis was performed using GraphPad Prism 7.0 statistical software. Correlation analysis was performed using Spearman rank correlation analysis. Student’s t test was used to compare the two sample means. Results Compared with adjacent tissues (1.20±0.15), the expression level of miR-122 (3.06±0.26) in papillary thyroid carcinoma was significantly down-regulated, and the difference was statistically significant (t=5.972, P<0.01). Correlation analysis showed that miR-122 was negatively correlated with SIRT1 mRNA expression (r=-0.621, P<0.01). The relative luciferase activity of SIRT1 in miR-122 mimics transfection group was significantly lower than that in the control group, and the difference was statistically significant (t=17.730, P<0.01). The cell proliferation ability of miR-122 mimics group was significantly lower than that of the control group, and the difference was statistically significant (t=3.991, P<0.01). After co-transfection of the SIRT1 overexpression plasmid, the inhibition of the proliferation of thyroid papillary carcinoma cells by miR-122 mimics was reversed. Conclusion miR-122 can inhibit the proliferation of papillary thyroid cancer cells, and its mechanism may be related to the targeted inhibition of SIRT1 expression. Key words: MicroRNA-122; Ilent information regulator 1; Papillary thyroid cancer; Proliferation

Silencing of zinc finger protein 703 inhibits medullary thyroid carcinoma cell proliferation in vitro and in vivo.

Zinc finger protein 703 (ZNF703) is a new member of the zinc finger protein family of transcription factors that plays an important role during embryogenesis in metazoans. The overexpression of ZNF703 contributes to tumorigenesis and progression of a number of malignancies by activating the Akt/mammalian target of rapamycin (mTOR) signaling pathway. This pathway is activated in medullary thyroid cancer (MTC), but its mechanism of action is not yet fully understood. The aim of the present study was to examine the role of ZNF703 and its association with Akt/mTOR activation in MTC. The present study used the phosphorylation of Akt1 protein at serine 473 (pAkt473) as an indicator of signaling activation. Immunohistochemistry (IHC) staining and western blot analyses were performed in order to examine the expression of ZNF703 in 34 cases of MTC and 12 cases of corresponding normal thyroid tissues. ZNF703 expression in MTC was significantly higher compared with the corresponding normal thyroid tissues (P<0.05). Furthermore, expression of ZNF703 was associated with tumor size, lymph node metastasis and advanced stage of disease. IHC also demonstrated that the level of ZNF703 was positively correlated with p-Akt473 in the 34 cases of MTC. The human MTC cell line TT was selected for further investigation as TT cells exhibit Akt/mTOR activation. The biological effects of silencing ZNF703 in TT cells on proliferation and apoptosis, both in vitro and in vivo were investigated in the present study. ZNF703 silencing inhibited the proliferation of TT cells in vitro and inhibited xenograft tumor growth in vivo. These effects were accompanied by the substantial decrease of pAkt473 and the induction of p53 protein. These results demonstrate that ZNF703 may play a relevant role in MTC due to its association with the Akt/mTOR signaling pathway.

Downregulation of microR-147b represses the proliferation and invasion of thyroid carcinoma cells by inhibiting Wnt/β-catenin signaling via targeting SOX15

microRNA-147b (miR-147b) is a newly identified tumor-related miRNA that is dysregulated in multiple cancer types. Yet, the role of miR-147b in thyroid carcinoma remains unknown. Herein, we found that miR-147b expression was upregulated in thyroid carcinoma tissues and cell lines. miR-147b inhibition decreased the proliferation, colony formation, and invasion of thyroid carcinoma cells. The tumor suppressive gene SRY-related high-mobility-group box gene 15 (SOX15) was predicted as a miR-147b target gene. SOX15 expression was markedly decreased in thyroid carcinoma tissues and inversely correlated with the miR-147b expression. SOX15 overexpression repressed the proliferation and invasion of thyroid carcinoma cells associated with downregulation of Wnt/β-catenin signaling. SOX15 knockdown abolished the miR-147b-inhibition-mediated antitumor effect. miR-147b inhibition or SOX15 overexpression retarded the tumor growth of thyroid carcinoma cells in vivo. Overall, our study suggests that miR-147b inhibition restrains the proliferation and invasion of thyroid carcinoma cells through upregulation of SOX15 and inhibition of Wnt/β-catenin signaling.