Thyroid Cancer Cell Proliferation Research Articles

Effects of CDK6 regulated by miR-298 on proliferation and apoptosis of thyroid cancer cells.

Effects of CDK6 regulated by miR-298 on proliferation and apoptosis of thyroid cancer cells were explored. Seventy-five cases of thyroid carcinoma and adjacent tissues were collected. The expression levels of miR-298 and CDK6 mRNA in tissues and cells were detected by RT-PCR. In addition, thyroid cancer cells and human normal thyroid cells Nthy-ori3-1 were purchased, with the former transfected with miR-298-mimics, miR-298-inhibitor, miR-NC, si-CDK6, si-NC, Sh-CDK6, Sh-NC to build cell models. Then the expression levels of miR-298 and CDK6 in thyroid cancer tissues and cells were detected by qRT-PCR, and the expression of CDK6, Bax, Bcl-2 and caspase-3 by WB. CCK-8 and flow cytometry were employed to detect cell proliferation and apoptosis, and dual luciferase report was adopted to determine the relationship between miR-298 and CDK6. miR-298 was underexpressed in thyroid cancer, and CDK6 was highly expressed in thyroid cancer. Cell experiments revealed that overexpression of miR-298 or inhibition of CDK6 expression could suppress cell proliferation, promote apoptosis, and significantly increase the expression levels of Bax and caspase-3 proteins, decrease Bcl-2 protein expression, which was contrary to the biological phenotype of cells after inhibition of miR-298 or further overexpression of CDK6. Dual luciferase report confirmed that miR-298 was a targeting site of CDK6. miR-298 can inhibit the proliferation of thyroid cells and promote apoptosis of thyroid cancer cells by regulating the expression of CDK6, which is expected to be a potential target for clinical application.

Hsa_circ_0011385 accelerates the progression of thyroid cancer by targeting miR-361-3p

BackgroundThyroid cancer is an endocrine malignancy that is growing in incidence worldwide. Despite progress in diagnostics and treatment of thyroid cancer, prognosis remains poor. Emerging research has shown that circular RNAs (circRNAs) have crucial regulatory roles in cancers. However, the possible functions and mechanisms of hsa_circ_0011385 remain undetermined.Materials and methodsExpression levels of hsa_circ_0011385 and miR-361-3p were evaluated by qRT-PCR assay. The interaction between hsa_circ_0011385 and miR-361-3p was verified by dual-luciferase reporter assay. Effects of hsa_circ_0011385 or miR-361-3p on cell viability, proliferation, cell cycle, apoptosis, migration and invasion were confirmed by cell counting kit-8 (CCK-8), carboxyfluoresceinsuccinimidyl ester (CFSE), flow cytometry, and Transwell assays in vitro. The effect of hsa_circ_0011385 on thyroid cancer progression was also determined by in vivo tumor formation assay. Target genes of miR-361-3p were predicted by gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, and the expression of apoptosis- and metastasis-related proteins were assessed by Western blot assay.ResultsHsa_circ_0011385 upregulated in thyroid cancer; hsa_circ_0011385 knockdown inhibited thyroid cancer cell proliferation, migration and invasion, and promoted cell cycle arrest and apoptosis. In addition, hsa_circ_0011385 could negatively regulate miR-361-3p by functioning as a sponge. Hsa_circ_0011385 promoted thyroid cancer cell proliferation, migration and invasion and suppressed cell cycle arrest and apoptosis by targeting miR-361-3p in vitro. We also found that hsa_circ_0011385 knockdown dramatically inhibited thyroid cancer growth in vivo. Furthermore, hsa_circ_0011385 regulated expression of apoptosis and metastasis-related proteins in thyroid cancer.ConclusionsHsa_circ_0011385facilitated thyroid cancer cell proliferation, invasion and migration, and inhibited thyroid cancer cell cycle arrest and apoptosis by targeting miR-361-3p, suggesting that the hsa_circ_0011385/miR-361-3p axis might be a promising therapeutic target for thyroid cancer.

Ginsenoside Rh2 inhibits thyroid cancer cell migration and proliferation via activation of miR-524-5p.

IntroductionThyroid cancer is an important disease that threatens the health of humans. Ginsenoside Rh2 is known as an anticancer molecule; however, its function in thyroid cancer cells has not been reported. In the present study, we identified that Rh2 treatment of the thyroid cancer cell line K1 inhibited cell migration and proliferation.Material and methodsWe determined the Rh2 function in thyroid cancer cell lines. By RT-PCR, expression of miR-524-5p and related genes were determined. The cell phenotype including cell migration and proliferation were detected after serials treatment. The relevant protein level were checked by Western blot.ResultsInterestingly, we observed that miR-524-5p, a type of miRNA, had lower expression in the thyroid cancer cell lines TPC-1, K1, and NPA than in the normal thyroid cell line Nthyri3-1. Additionally, Rh2 treatment induced miR-524-5p expression. Further examination using overexpression of miR-524-5p identified that the miR-524-5p mimic inhibited cell migration and proliferation of the K1 line. Similar to Rh2-treated cells, the miR-524-5p mimic-expressing cells had increased E-cadherin and reduced vimentin levels compared to the control cells. Next, we examined the relationship between Rh2 and miR-524-5p with respect to thyroid cell migration and proliferation. Treatment with Rh2 and miR-524-5p inhibitor suppressed Rh2 action on K1 thyroid cell migration and proliferation, and the rates were similar to those in control cells, suggesting that Rh2 might induce miR-524-5p expression to inhibit thyroid cancer cell migration and proliferation.ConclusionsOur analyses identified Rh2 and miR-524-5p action on thyroid cancer cell migration and proliferation as well as the linkage between Rh2 and miR-524-5p in thyroid cancer cell development.

Propofol upregulates miR-320a and reduces HMGB1 by downregulating ANRIL to inhibit PTC cell malignant behaviors

BackgroundOur previous study states that propofol suppresses proliferation and migration of papillary thyroid cancer (PTC) cells by downregulation of lncRNA ANRIL. This study intended to probe the downstream mechanism of ANRIL in PTC with potential microRNAs (miR) and genes. MethodsANRIL expression was detected in normal thyroid epithelial cells (Nthy-ori 3-1) and PTC cells (TPC-1, FTC-133, K1 and BCPAP). ANRIL expression was inhibited in TPC-1 and BCPAP cells to explore the effects of si-ANRIL in PTC malignant behaviors. The gain-and loss-of functions of ANRIL/miR-320a were performed to measure their roles in PTC. Levels of ANRIL, miR-320a, HMGB1, apoptosis- and Wnt/β-catenin and NF-κB pathways-related proteins were measured. Dual-luciferase reporter gene assay and RNA pull-down assay were applied to verify ANRIL/miR-320a/HMGB1 relation. si-ANRIL was transplanted into xenograft tumors in nude mice. ResultsANRIL was upregulated in TPC-1 and BCPAP cells. miR-320a targeted HMGB1, and ANRIL bound to miR-320a. In TPC-1 and BCPAP cells, si-ANRIL prevented PTC cell malignant behaviors, and inactivated the Wnt/β-catenin and NF-κB pathways; while si-ANRIL + miR-320a inhibition showed opposite trends. Overexpressing miR-320a promoted malignant behaviors of TPC-1 cells. In 6 μg/mL propofol-treated TPC-1 cells, miR-320a inhibition weakened propofol’s inhibitory effects on PTC cell growth. After ANRIL inhibition, the volume and weight of xenograft tumors were decreased. ConclusionPropofol upregulated miR-320a and reduced HMGB1 by downregulating ANRIL and inactivating the Wnt/β-catenin and NF-κB pathways, thus preventing PTC cell malignant behaviors. This study may offer new insights in PTC prevention and treatment.

Non-toxic fragment of botulinum neurotoxin type A and monomethyl auristatin E conjugate for targeted therapy for neuroendocrine tumors.

Surgical resection is the only cure for neuroendocrine tumors (NETs). However, widespread metastases have already occured by the time of initial diagnosis in many cases making complete surgical removal impossible. We developed a recombinant heavy-chain receptor binding domain (rHCR) of botulinum neurotoxin type A that can specifically target synaptic vesicle 2 (SV2), a surface receptor abundantly expressed in multiple neuroendocrine tumors. Expression of neuroendocrine differentiation markers chromogranin A (CgA) and achaete-scute complex 1 (ASCL1) were signficantly reduced when treated with rHCR. rHCR conjugated to the antimitotic agent monomethyl auristatin E (MMAE) significantly suppressed proliferation of pancreatic carcinoid (BON) and medullary thyroid cancer cells (MZ) at concentrations of 500 and 300 nM respectively, while no growth suppression was observed in pulmonary fibroblasts and cortical neuron control cell lines. In vivo, rHCR-MMAE significantly reduced tumor volume in mouse xenografts with no observed adverse effects. These data suggest recombinant HCR (rHCR) of BoNT/A preferentially targets neuroendocrine cancer without the neurotoxicity of the full BoNT/A and that SV2 is a specific and promising target for delivering drugs to neuroendocrine tumors.

MicroRNA-575 targets Derlin 1 to regulate proliferation, migration and invasion of human thyroid cancer cells.

This study was undertaken to examine the expression of miR-575 in thyroid cancer tissues and to explore its therapeutic potential. Expression analysis was carried out by qRT-PCR. The MTT assay was used for cell viability. DAPI and annexin V/PI assays were used to detect apoptosis. Wound healing and Transwell assays were used for cell migration and invasion respectively. Western blot analysis was used to determine the expression of proteins. The results showed significant downregulation of miR-575 in thyroid cancer tissues and cell lines. The role of miR-575 was deciphered by overexpression of miR-575 in MDA-T32 and MDA-T68 thyroid cancer cells. The results showed that overexpression of miR-575 caused significant inhibition of the proliferation of the MDA-T32 and MDA-T68 cells via induction of apoptotic cell death. The expression of Bax was also enhanced while that of Bax was decreased upon miR-575 overexpression in MDA-T32 and MDA-T68 cells. Additionally, miR-575 overexpression inhibited the migration and invasion of the MDA-T32 and MDA-T68 thyroid cancer cells. Bioinformatic approaches and the dual luciferase assay indicated Derlin 1 (DERL1) to be the potential target of miR-575 in thyroid cancer. DERL1 was significantly upregulated in thyroid cancer tissues and cell lines and overexpression of miR-575 caused suppression of DERL1 in MDA-T68 cells. Silencing of DERL1 inhibited the proliferation of the MDA-T68 cells while overexpression of DERL1 could abolish the effects of miR-575 overexpression on the proliferation of MDA-T68 thyroid cancer cells. miR-575 may be used as a therapeutic target for thyroid cancer treatment.

The function of SNHG7/miR-449a/ACSL1 axis in thyroid cancer.

Thyroid cancer (TC) has been characterized as the most common malignant malady of the endocrine system. Small nucleolar RNA host gene 7 (SNHG7) has been reported to serve as a key regulator in a large number of human cancer types, but its role in TC and the underlying regulatory mechanism have never been evaluated yet. The present study indicated that the expression of SNHG7 was markedly higher in TC cell lines. Knockdown of SNHG7 led to a suppression of TC cell progression and migration. Acyl-CoA synthetase long-chain family member 1 (ACSL1) has also been demonstrated as an oncogene in many cancers. Herein an inhibition of ACSL1 after SNHG7 knockdown was captured. Further, the suppressing effects of SNHG7 knockdown on TC cell processes were counteracted by ACSL1 overexpression. Data from online bioinformatics analysis, RNA immunoprecipitation, and luciferase reporter assays validated the interaction between microRNA-449a (miR-449a) and SNHG7 or ACSL1. It was also verified that SNHG7 sequestered miR-449a and therefore elevated ACSL1 expression levels. To conclude, the current study indicated that SNHG7 promoted proliferation and migration of TC cells by sponging miR-449a and therefore upregulating ACSL1. The present study may provide more explorations about the molecular regulation mechanism of long noncoding RNAs in TC progression.

The TUSC2 Tumour Suppressor Inhibits the Malignant Phenotype of Human Thyroid Cancer Cells via SMAC/DIABLO Protein.

Thyroid carcinoma is the most common endocrine cancer and includes different forms. Among these, anaplastic thyroid carcinoma (ATC) is the rarest but the most lethal subtype, compared to papillary thyroid carcinoma (PTC) which shows an overall good prognosis. We have previously showed that Tumor Suppressor Candidate 2 (TUSC2), a known tumour suppressor gene, is downregulated in human PTC and ATC compared to normal thyroid samples. The aim of this study was to gain insight into the molecular mechanisms induced by TUSC2 in thyroid cancer cells. Here, we stably transfected TUSC2 in papillary (TPC-1) and in anaplastic (8505C) thyroid cancer cell lines and studied its effects on several biological processes, demonstrating that TUSC2 overexpression decreased thyroid cancer cell proliferation, migration and invasion. Through the proteome profiler apoptosis array, we observed that TUSC2 increased sensitivity to apoptosis by increasing the SMAC/DIABLO and CYTOCHROME C proteins. On the other hand, transient silencing of TUSC2, by siRNA, in an immortalized thyroid follicular epithelial cell line (Nthy-ori 3-1) showed the opposite effect. Finally modulation of SMAC/DIABLO partially rescued the biological effects of TUSC2. Thus, our data highlight a tumour suppressor role of TUSC2 in thyroid carcinogenesis, suggesting that it could be a promising target and biomarker for thyroid carcinoma.

RETRACTED: Upregulation of OIP5-AS1 Predicts Poor Prognosis and Contributes to Thyroid Cancer Cell Proliferation and Migration

As a common malignancy, thyroid cancer mainly occurs in the endocrine system. There have been accumulating studies on therapeutic methods of thyroid cancer, but its internal molecular mechanism is still not fully understood. Long noncoding RNA (lncRNA) OIP5-AS1 was confirmed as an oncogene and related to poor prognosis in various cancers. Nevertheless, its role and underlying mechanism remain unclear in thyroid cancer. Here, we observed a significant upregulation of OIP5-AS1 in thyroid cancer tissues and cells, and upregulated OIP5-AS1 was correlated with poor prognosis in thyroid cancer. Moreover, OIP5-AS1 knockdown resulted in the inhibited cell proliferation and migration, while overexpressed OIP5-AS1 exhibited the reverse function in thyroid cancer. Besides, OIP5-AS1 was found to positively regulate Wnt/β-catenin signaling pathway. Through mechanism exploration, OIP5-AS1 was discovered to activate Wnt/β-catenin signaling pathway via FXR1/YY1/CTNNB1 axis. Finally, rescue assays indicated that the inhibitive role of silenced OIP5-AS1 in thyroid cancer cell growth and Wnt/β-catenin signaling pathway could be rescued by overexpression of CTNNB1 or addition of lithium chloride (LiCl). In conclusion, upregulation of OIP5-AS1 predicted unfavorable prognosis and enhanced thyroid cancer cell growth by activating Wnt/β-catenin signaling pathway.

Effect of miR-205 on proliferation and migration of thyroid cancer cells by targeting CCNB2 and the mechanism.

This study explored the target of miR-205 and the effect of miR-205 on the proliferation and migration regulating its target in thyroid cancer cells (TC). Twenty-five pairs of TC and adjacent tissues were collected after surgical resection. Real-time fluorescence quantitative PCR (qRT-PCR) was used to detect the expression of miR-205 in TC tissues and cells (SW579, B-CPAP, TPC-1, WRO). SW579 cells were transfected with miR-205 mimic, and SW579 cells with overexpression of miR-205 were constructed. The effects of miR-205 overexpression on the proliferation and migration of SW579 cells were observed by cell counting kit-8 (CCK-8) and Transwell assays, respectively. Luciferase reporter assay was further used to look for the target of miR-205 and to study the mechanism of miR-205 in the proliferation and migration of TC cells. Compared with normal tissues and cells, the expression of miR-205 was significantly reduced in TC tissues (t=3.47, P=0.031) and cells (t=5.41, P=0.016). Overexpression of miR-205 inhibited the proliferation (t=4.12, P=0.035) and migration (t=4.47, P=0.027) of SW579 cells. Luciferase reporter assays found that CCNB2 was a target gene of miR-205 (t=4.63, P=0.024), qRT-PCR and western blot assays confirmed there was negatively correlation between CCNB2 and miR-205 (t=3.55, P=0.029; t=2.86, P=0.043). CCNB2 overexpression reversed the inhibition of miR-205 on the proliferation (t=3.70, P=0.031) and migration (t=4.12, P=0.022) of SW579 cells. In conclusion, miR-205 inhibits the proliferation and migration of TC cells by targeting CCNB2, which may be a potential target of TC therapy.

Nanoparticles carrying fingolimod and methotrexate enables targeted induction of apoptosis and immobilization of invasive thyroid cancer

Metastatic tumors are the main cause of cancer-related death, as the invading cancer cells disrupt normal functions of distant organs and are nearly impossible to eradicate by traditional cancer therapeutics. This is of special concern when the cancer has created multiple metastases and extensive surgery would be too dangerous to execute. Therefore, combination chemotherapy is often the selected treatment form. However, drug cocktails often have severe adverse effects on healthy cells, whereby the development of targeted drug delivery could minimize side-effects of drugs and increase the efficacy of the combination therapy. In this study, we utilized the folate antagonist methotrexate (MTX) as targeting ligand conjugated onto mesoporous silica nanoparticles (MSNs) for selective eradication of folate receptor-expressing invasive thyroid cancer cells. The MSNs was subsequently loaded with the drug fingolimod (FTY720), which has previously been shown to efficiently inhibit proliferation and invasion of aggressive thyroid cancer cells. To assess the efficiency of our carrier system, comprehensive in vitro methods were employed; including flow cytometry, confocal microscopy, viability assays, invasion assay, and label-free imaging techniques. The in vitro results show that MTX-conjugated and FTY720-loaded MSNs potently attenuated both the proliferation and invasion of the cancerous thyroid cells while keeping the off-target effects in normal thyroid cells reasonably low. For a more physiologically relevant in vivo approach we utilized the chick chorioallantoic membrane (CAM) assay, showing decreased invasive behavior of the thyroid derived xenografts and an increased necrotic phenotype compared to tumors that received the free drug cocktail. Thus, the developed multidrug-loaded MSNs effectively induced apoptosis and immobilization of invasive thyroid cancer cells, and could potentially be used as a carrier system for targeted drug delivery for the treatment of diverse forms of aggressive cancers that expresses folate receptors.

MiR-154-3p and miR-487-3p synergistically modulate RHOA signaling in the carcinogenesis of thyroid cancer.

Background: miRs family members are often thought to have extensively overlapping targets and synergistically to modulate target gene expression via post-transcriptional repression. The present study was to determine whether miR-154-3p and miR-487-3p synergistically collaborated to regulate RHOA signaling in the carcinogenesis of thyroid cancer. Materials and methods: Candidate miRs were filtrated using miR microarray assays. Gene and protein expression levels were analyzed using RT-qPCR and Western blotting, respectively. Cell growth was evaluated using CCK8 assays and nude-mouse transplanted tumor experiments. Cell apoptosis was detected using Annexin V-FITC double staining. Results: miR-154-3p and miR-487-3p were significantly decreased in 63 thyroid cancer tissues and cell lines compared with those in paired non-tumor tissues and normal thyroid follicular epithelial cells. Low expression levels of miR-154-3p and miR-487-3p significantly correlated with tumor size, TNM stage, histological grade, lymph node metastasis and shorter overall survival in patients with thyroid cancer. Furthermore, the protein expression of RHOA was significantly inversely correlated with miR-154-3p (r = −0.404; P = 0.001) and miR-487-3p (r = −0.456; P < 0.001) expression in thyroid cancer tissues. We experimentally validated that miR-154-3p and miR-487-3p synergistically blocked thyroid cancer cell growth in vitro and in vivo. However, the anti-proliferative and pro-apoptotic activities of miR-154-3p/487-3p were neutralized by RHOA overexpressed vectors. Conclusions: Our present findings expounded a novel signal cascade employing miR-154-3p/487-3p and RHOA to fine-tune thyroid cancer cell proliferation and apoptosis. We corroborated that suppression of RHOA by miR-154-3p/487-3p may be a valuable therapeutic target for impeding thyroid cancer progression.

Long noncoding RNA UCA1 promotes proliferation and metastasis of thyroid cancer cells by sponging miR-497-3p.

Recently, long noncoding RNAs (lncRNAs) have attracted much attention for their roles in tumor progression. The aim of this study was to investigate the exact role of lncRNA UCA1 in the development of thyroid cancer (TC) and to explore the possible underlying mechanism. UCA1 expression in both TC cells and tissues was detected by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). Colony formation assay, cell proliferation, and transwell assay were conducted in vitro. Subsequent luciferase reporter gene assay was applied to investigate the underlying mechanism. Furthermore, the function of UCA1 in vivo was monitored as well. UCA1 expression level in TC samples was significantly higher than that of corresponding normal tissues. After UCA1 was knocked down in vitro and in vivo, the proliferation, migration, and invasion of TC cells were significantly inhibited. Moreover, the expression of miR-497-3p was repressed after the knockdown of UCA1. Furthermore, miR-497-3p was directly targeted by UCA1. Knockdown of UCA1 could inhibit TC cell proliferation and metastasis via sponging miR-497-3p. Our findings might offer a new therapeutic intervention for TC patients.

Overexpression of long noncoding RNA ENST433110 inhibits cell proliferation and migration and enhances cell apoptosis of thyroid cancer cells

Abnormal long noncoding RNAs (lncRNAs) participate in the generation and progression of malignancies. We aimed to determine the expression and clinical importance of lncRNA ENST433110 in thyroid cancer (TC). We thus investigated the role of ENST433110 in TC cell invasion, migration, and proliferation. ENST433110 expression was assessed using RT-PCR, cell migration was evaluated using a Transwell assay, and cell apoptosis was analyzed by flow cytometry. Our findings revealed that ENST433110 expression was dramatically reduced in TC sample tissues and TC cells (B-CPAP and TPC-1). Moreover, we showed that lncRNA ENST433110 overexpression inhibited cell migration and proliferation in TC cells. Furthermore, lncRNA ENST433110 overexpression enhanced cell apoptosis and induced a noticeable reduction in Bcl-2 expression and an increase in BAX expression in both TPC-1 and B-CPAP cells compared with that in control groups. In summary, our results indicate that lncRNA ENST433110 is important in the development of thyroid carcinoma and could thus be a promising target in thyroid carcinoma treatment.

SREBP1 as a potential biomarker predicts levothyroxine efficacy of differentiated thyroid cancer

BackgroundSREBP1 is a well-known transcript factor regulating lipogenesis. It has been reported to play an important role in tumor progress in recent years. However, the roles of SREBP1 in differentiated thyroid cancer (DTC) are uncertain. Based on this, we aimed to investigate the expression of SREBP1 and the influence of SREBP1 on DTC patients. MethodsqRT-PCR and immunohistochemistry were used to detect the expression of SREBPs in DTC tissues and the adjacent normal tissues. The following methods, including the MTS, colony-forming assay, flow cytometry and Hoechst staining were used to detect the biological function of thyroid cancer cells based on SREBP1 interference or not. Resultsthe expression of SREBP1 was significantly different among DTCs, thyroid nodules and the adjacent normal tissues. Briefly, SREBP1 was upregulated follow with the malignancy, but there was no significant difference of SREBP2 between thyroid nodules and the adjacent normal tissues. Further, the ROC curve showed that SREBP1 has higher diagnostic value than SREBP2. SREBP1 expression was significantly related to the tumor size and lymph node metastasis in DTCs. In vitro, the proliferation of thyroid cancer cells was suppressed obviously after interfered with SREBP1, and the apoptotic cells was increased. Further, SREBP1 expression was also associated with the short-term efficacy of levothyroxine in DTC patients. Conclusionthis is the first time to report that SREBP1 is an oncogene and a pro-proliferation factor in thyroid cancer, indicating that SREBP1 may serve as a potential biomarker and therapeutic target in thyroid cancer.

Sodium Selenite Enhanced the Anti-proliferative Effect of MEK-ERK Inhibitor in Thyroid Cancer Cells.

MEK-ERK pathway plays major roles in the progression of thyroid cancer, while the use of MEK-ERK inhibitors has been limited by its toxicity. We investigated the effect of sodium selenite as an adjunct for MEK-ERK inhibitors to avoid the toxicity of ERK inhibitors. TPC1, 8505C and HTori-3 cells were treated with U0126 (MEK-ERK inhibitor) and cell viability was counted in the Neubauer chamber. The synergistic effects of sodium selenite and U0126 were also measured. The expression of ERK, p-ERK, and p90RSK was determined by western blot. Treatment with U0126 inhibited proliferation of TPC1 and 8505C cells in a dose-dependent manner. When 5 μM sodium selenite was added to 1 μM U0126, relative cell survival further decreased. Decreased expression of p90RSK indicated that sodium selenite down-regulated ERK signaling in thyroid cancer cells. The combination of U0126 and sodium selenite inhibited proliferation of thyroid cancer cells through ERK inhibition.

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

Circular RNA circ_0067934 exhaustion expedites cell apoptosis and represses cell proliferation, migration and invasion in thyroid cancer via sponging miR-1304 and regulating CXCR1 expression.

Distant metastasis or local recurrence is the leading cause of death in some patients with thyroid cancer (TC), a malignant tumor of the endocrine system. Circular RNA circ_0067934 (circ_0067934) has been reported to be connected with the tumorigenesis of multiple tumors. However, there are few reports on the role and regulatory mechanisms of circ_0067934 in TC. The expression levels of circ_0067934, protein kinase C iota (PRKCI), microRNA-1304 (miR-1304), and C-X-C chemokine receptor types 1 (CXCR1) were detected with quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). The proliferation, apoptosis, migration, and invasion of TC cells were evaluated by Cell Counting Kit-8 (CCK8) assay, flow cytometry assay, and transwell assay, respectively. The relationship between circ_0067934 or CXCR1 and miR-1304 was confirmed with Dual-Luciferase reporter assay or RNA immunoprecipitation (RIP) assay. Protein level of CXCR1 was analyzed via Western blot analysis. Xenograft assay was executed to verify the role of circ_0067934 in vivo. Circ_0067934 and CXCR1 were enhanced and miR-1304 decreased in TC tissues and cells. Circ_0067934 downregulation triggered apoptosis and curbed proliferation, migration, and invasion of TC cells in vitro, as well as repressed tumor growth in vivo. Notably, circ_0067934 regulated CXCR1 expression via sponging miR-1304 in TC cells. Both miR-1304 silencing and CXCR1 elevation reversed the facilitation of apoptosis and the retardation of proliferation, migration, and invasion induced by circ_0067934 reduction in TC cells. Circ_0067934 downregulation expedited apoptosis and retarded proliferation, migration, and invasion of TC cells through miR-1304/CXCR1 axis.

LncRNA DARS-AS1 regulates microRNA-129 to promote malignant progression of thyroid cancer.

To investigate the expression of long non-coding RNA (lncRNA) DARS-AS1 in thyroid cancer, and to further investigate whether it can promote the development of thyroid cancer by regulating microRNA-129. Real-time quantitative polymerase chain reaction (qPCR) was used to detect the level of DARS-AS1 in tumor tissues and paracancerous tissues of 34 thyroid carcinomas. It was also used to analyze the relationship between the expression of DARS-AS1 and the clinical indicators of thyroid cancer and the prognosis of patients. qPCR was used to further verify the expression of DARS-AS1 in thyroid cancer cell lines. The DARS-AS1 knockdown model was constructed using lentivirus in thyroid cancer cell lines. Cell counting kit-8 (CCK-8), cell clone formation, and transwell migration assays were performed to evaluate the effects of DARS-AS1 on the biological function of thyroid cancer cells. Finally, the potential mechanism was explored by using recovery experiments and the interplay between DARS-AS1 and microRNA-129 was further studied. qPCR results revealed that the level of DARS-AS1 in tumor tissues of thyroid cancer patients was remarkably higher than that in adjacent tissues, and the difference was statistically significant. Compared with patients with low expression of DARS-AS1, patients with high DARS-AS1 expression had a higher incidence of high tumor stage, distant metastasis, and a lower overall survival rate. Besides, compared with NC group, the proliferation and migration ability of shRNA-AS1 expression knockdown group sh-DARS-AS1 was remarkably decreased. qPCR results indicated that there was a negative correlation between the level of microRNA-129 and DARS-AS1 in thyroid cancer tissues. In addition, cell proliferation and migration ability in the microRNA-129 overexpression group were remarkably decreased. The recovery experiment also found that there was a mutual regulation between DARS-AS1 and microRNA-129, which together affected the malignant progression of thyroid cancer. DARS-AS1 level in tumor tissues of thyroid cancer was remarkably increased and was correlated with the pathological stage, distant metastasis, and poor prognosis of thyroid cancer. Moreover, DARS-AS1 could promote the proliferation and migration capabilities of thyroid cancer cells by modulating microRNA-129.

Expression and function of long non-coding RNA LINC01420 in thyroid cancer.

The Human Genome Project revealed that >90% of the human genome was found to transcribe non-coding RNAs, including micro RNAs and long non-coding RNAs (lncRNAs). lncRNAs have been identified to play a crucial role in cancer progression. Thyroid cancer (TC) is a common type of endocrine cancer; however, the functional roles of lncRNAs in TC have yet to be fully elucidated. The present study investigated whether LINC01420 was upregulated in TC tissues, compared with normal thyroid tissues, and the results suggested that LINC01420 may play a regulatory role in TC. Bioinformatics analysis demonstrated that LINC01420 was associated with translation, rRNA processing, mRNA splicing, regulation of transcription, DNA repair and double-strand break repair. Furthermore, the exact role of LINC01420 in TC was explored by performing a loss-of-function assay, which revealed that the knockdown of LINC01420 inhibited TC cell proliferation and cell cycle progression. The findings of the present study provide a novel insight into the molecular mechanisms underlying TC development. Moreover, they suggest that LINC01420 may serve as a potential therapeutic target for the treatment of TC, and that increased LINC01420 expression levels show potential as a prognostic marker for the disease.