Thyroid Cancer Cell Proliferation Research Articles

Apatinib weakens proliferation, migration, invasion, and angiogenesis of thyroid cancer cells through downregulating pyruvate kinase M2

Thyroid cancer (TC) is the most frequent malignancy of the endocrine system. Apatinib, as an anti-angiogenic agent, has been applied in the therapy of several cancers. However, the function and mechanism of Apatinib in TC have not been clearly elucidated. After processing with Apatinib alone or combined PKM2 overexpression plasmids, cell proliferation, migration, and invasion were analyzed by EdU staining, CCK-8, wound healing, and Transwell. Meanwhile. HUVECs were incubated with the conditioned medium prepared from cell culture medium, and tube formation and VEGFR2 expression in HUVECs were examined using tube formation and immunofluorescence (IF) assays. Besides, we established a nude mouse xenograft model by lentivirus-mediated PKM2 shRNAs, and tested the growth of tumors; the pathological structure was analyzed with H&E staining. And the expressions of N-cadherin, Vimentin, E-cadherin, PKM2, VEGFA, VEGFR2, and Ki67 were determined by immunohistochemistry or Western blot. Apatinib could prominently suppress proliferation, migration, invasion, and HUVEC tube formation in SW579 and TPC-1 cells. Besides, we discovered that Apatinib had a significant inhibitory role on the expression of pyruvate kinase M2 (PKM2) in TC cells. And PKM2 overexpression also could notably reverse Apatinib-mediated inhibition of TC progression. Moreover, PKM2 shRNAs were applied to TC xenografts, resulting in significant reduction in tumor volume and suppression of angiogenesis-related protein expression. In summary, Apatinib has a regulatory role in TC progression, and Apatinib can block cancer cell angiogenesis by downregulating PKM2. This will provide a theoretical basis for therapy of TC.

Asiaticoside Down-Regulates HIF-1α to Inhibit Proliferation, Migration, and Angiogenesis in Thyroid Cancer Cells

Thyroid cancer (TC), the most prevalent endocrine malignancy, has been subjected to various treatment methods. However, the efficacy of asiaticoside (AC) for treating TC remains uncertain. To explore the impact of AC on TC and determine its potential mechanisms of action. In vitro and in vivo cell line study. We evaluated the effects of AC on human TC cell lines, namely TPC-1 and FTC-133. Both in vitro and in vivo experimental validations were conducted. AC significantly diminished the viability and proliferation of TC cells based on the CCK-8 assay and Edu staining findings. Migration and invasion assays revealed that AC effectively curtailed the migration and invasiveness of TC cells. The tube formation assay demonstrated that AC substantially impeded TC cell-induced angiogenesis. Western blot assay revealed that AC significantly reduced the expression levels of TRAF6, HIF-1α, and VEGFA, indicating that AC could potentially exert its anticancer effect by inhibiting the TRAF6/HIF1α pathway. Our in vivo experiments, which involved administering AC to BALB/c nude mice injected with TPC-1 cells, demonstrated significant inhibition of tumor growth and reduction in the expression of Ki-67, TRAF6, HIF-1α, and VEGFA. Our study highlights the significant inhibitory effect of AC on TC, offering fresh insights and potential drug candidates for TC treatment.

MiRNA-363-3p Hinders Proliferation, Migration, Invasion and Autophagy of Thyroid Cancer Cells by Controlling SYT1 Transcription to affect NF-κB.

Thyroid cancer (TC) is a frequent endocrine malignant tumor with various pathologic types. miRNA-363-3p plays a pivotal part in the occurrence, development, prognosis, and treatment of cancer. To explore the mechanism of miRNA-363-3p in TC and provide a new idea for targeted therapy of TC. Differential miRNAs and downstream target mRNAs in TC tissues were predicted with bioinformatics analysis. Expression levels of miRNA-363-3p and Synaptotagmin I (SYT1) in TC cells were ascertained by qRT-PCR. Cell migration, invasion, and proliferation were detected by wound healing assay, transwell assay, colony formation assay, CCK-8, and BrdU fluorescence experiment, respectively. Flow cytometry was utilized to detect the levels of apoptosis and necrosis. Immunofluorescence assay was used for detecting autophagosome formation in cells, and the expression levels of autophagy-related proteins, as well as NF-κB related proteins, were measured by western blot. Dual-luciferase reporter gene assay was applied for detecting the interaction between miRNA-363-3p and SYT1. miRNA-363-3p was prominently down-regulated in TC cells. miRNA-363-3p overexpression suppressed migration, invasion, and proliferation, promoting apoptosis and necrosis of TC cells. As the downstream target of miRNA-363-3p, SYT1 was up-regulated in TC cells. SYT1 overexpression reversed the inhibition of TC cell proliferation, invasion, migration, and autophagy mediated by miRNA-363-3p overexpression. In addition, miRNA-363-3p overexpression inhibited the activation of the NF-κB pathway in cells, while further overexpression of SYT1 weakened the inhibition of miRNA-363-3p overexpression on the NF-κB pathway. miRNA-363-3p affected the NF-κB signaling pathway by down-regulating SYT1 expression to inhibit the malignant progression of TC cells, providing theoretical support for the treatment of TC.

USP44 inactivation accelerates the progression of thyroid cancer by inducing ubiquitylation and degradation of p21.

Ubiquitin-specific peptidase 44 (USP44) belongs to the ubiquitin-specific protease family and is pivotal in the development and progression of tumors across various human cancers. However, its biological function and the underlying mechanisms in thyroid cancer remain poorly understood. In this study, we observed that USP44 was frequently downregulated by promoter hypermethylation in thyroid cancers and found that its decreased expression was closely associated with poor patient survival. Subsequent in vitro and in vivo functional studies revealed that USP44 substantially suppressed the proliferation of thyroid cancer cells by impeding the G1/S transition in cell cycle. Mechanistically, USP44 directly interacted with p21 and eliminated its K-48-linked polyubiquitination chain, thereby stabilizing p21 proteins in a cell cycle-independent manner. In addition, the rescue of p21 partially alleviated cell cycle advancement and cell proliferation induced by the depletion of USP44. Our findings, taken together, indicate that USP44 is frequently repressed in thyroid cancer due to promoter hypermethylation and functions as a tumor suppressor by stabilizing p21 via deubiquitination.

COL4A2 enhances thyroid cancer cell proliferation through the AKT pathway.

Thyroid cancer (THCA) is the most common malignant tumor in endocrine system and the incidence has been increasing worldwide. And the number of patients dying from THCA has also gradually risen because the incidence continues to increase, so the mechanisms related to effective targets is necessary to improve the survival. This study was to preliminarily investigate the effects of the COL4A2 gene on the regulation of thyroid cancer (THCA) cell proliferation and the associated pathways. Bioinformatics analysis revealed that COL4A2 was closely associated with cancer development. COL4A2 expression in THCA tissues was analyzed using immunohistochemistry, and survival information was determined via Kaplan‒Meier curves. The expression of COL4A2 and AKT pathway-related genes were analyzed using qPCR and western blot analyses. Colony formation as well as CCK-8 assays exhibited the cell proliferation level and cell activity, respectively. Downstream of COL4A2 was identified by Gene set enrichment analysis (GSEA). The effects of the COL4A2 and AKT pathways on THCA tumor growth in vivo were determined using a mouse model. Bioinformatics analysis exhibited that COL4A2 plays a significant role in cancer and that the AKT pathway is downstream of COL4A2. THCA patients with high COL4A2 expression had shorter recurrence-free survival. Upregulation of COL4A2 gene expression in 2 THCA cell lines promoted tumor cell growth and activity. The use of AKT pathway blockers also restrained the growth and activity of the 2 THCA cell lines. The use of AKT pathway blockers reduced tumor volume and mass and prolonged mouse survival. COL4A2 can promote the growth as well as development of THCA through the AKT pathway and COL4A2 could be used as a target for THCA.

GLP-1 receptor agonist liraglutide inhibits the proliferation and migration of thyroid cancer cells.

This research was done to find out how liraglutide affected the growth and movement of two human thyroid cancer cell lines overexpressing GLP-1 receptor (migration of medullary thyroid cancer TT/GLP-1R and papillary thyroid carcinoma TCP-1/GLP-1R). Flow cytometer and cAMP assays were used to identify the expression and activation of GLP-1R in two stable cell lines. Counting Kit-8 for Cells was applied to examine the proliferative ability of cells in two stable cell lines after treatment with different concentrations of liraglutide at indicated time points. To track the capacity for cell migration, the Transwell test was utilized. We found that liralutide-activated GLP-1R could significantly reduce the growth and metastasis of two kinds of thyroid tumor cells, and the inhibitory effect was dose- and time- dependent. The phosphorylatios of Akt, S6K1, and 70SK declined after receiving liraglutide therapy In our previous studies, we found that the GLP-1 receptor agonist Liraglutide inhibited the proliferation and migration of thyroid cancer cells through the PI3K/Akt/mTOR pathway. This finding provides a theoretical basis for the treatment of diabetes mellitus complicated with medullary thyroid cancer, and is relatively safe.

Abstract C012: Exploring thrombospondin-1 variant and splicing factors as potential diagnostic biomarkers and therapeutic targets in thyroid cancer

Abstract Thyroid cancer is the most common type of cancer affecting the thyroid gland, accounting for 11.8% of all cancer cases in Korea as of 2020. The majority of thyroid cancer cases belong to the papillary thyroid cancer (PTC) subtype. Diagnostic methods for thyroid cancer include blood tests, ultrasound examinations, fine needle aspiration cytology (FNAC), PET/CT scans, and others. However, distinguishing between different subtypes of thyroid cancer, such as follicular variant of papillary thyroid carcinoma (FVPTC), follicular adenoma (FA), and follicular thyroid carcinoma (FTC), remains challenging, often leading to unnecessary surgeries for patients. In this study, antibody arrays were used to analyze tumor and adjacent normal tissues from thyroid cancer patients. Thrombospondin 1 (TSP1), was found to be more highly expressed in tumor tissue compared to normal tissue. TSP1 is a glycoprotein with diverse biological functions that can either inhibit or promote tumorigenesis depending on the context. The researchers discovered a transcriptional variant of TSP1 (TSP1V) generated by intron retention (IR), which was more highly expressed in normal tissue compared to tumor tissue. Overexpression of TSP1V in thyroid cancer cells resulted in the secretion of the protein into the medium or its deposition in the extracellular matrix (ECM). TSP1V exhibited anti-cancer properties, inhibiting proliferation, migration, invasion, colony formation, and spheroid formation of thyroid cancer cells in vitro. It also suppressed tumor growth in a mouse experiment. The researchers explored the TGF-β pathway, a well-known signaling pathway associated with TSP1, and found that TSP1V inhibited the phosphorylation of Smad2 and FAK, unlike TSP1 wild-type (TSP1W). To investigate the mechanism behind TSP1V's generation through IR, we examined splicing factors. RBM5 overexpression inhibited IR induced by anti-cancer compounds, while RBM5 knockdown increased IR. Sulindac sulfide, one of the compounds tested, increased IR by inhibiting the phosphorylation of RBM5. Additionally, trans-chalcone was found to increase IR by demethylating DNA. Trans-chalcone also reduced the expression of TSP1W, DNMT3b, and MeCP2 in a time-dependent manner. The study concluded by analyzing tumor and adjacent normal tissues from patients with follicular neoplasm (FN), including benign thyroid nodule (BTN) and differentiated thyroid carcinoma (DTC). We also observed significant differences in the ratio of TSP1V to TSP1W. These findings provide evidence that secreted proteins like TSP1 have the potential to serve as diagnostic biomarkers and therapeutic targets for thyroid cancer. Moreover, the study enhances our understanding of the molecular mechanisms underlying the anti-cancer activities of these proteins. Citation Format: Yukyung Hong, Ilju Kim, Hyunjin Moon, Jaehak Lee, Pattawika Lertpatipanpong, Chang Hwan Ryu, Junsun Ryu, Seung Joon Baek. Exploring thrombospondin-1 variant and splicing factors as potential diagnostic biomarkers and therapeutic targets in thyroid cancer [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr C012.

Methylation-Mediated Silencing of ATF3 Promotes Thyroid Cancer Progression by Regulating Prognostic Genes in the MAPK and PI3K/AKT Pathways.

Background: Aberrant expression of oncogenes and/or tumor suppressor genes (TSGs) drives the tumorigenesis and development of thyroid cancer. We investigated the expression and function of a member of the activating transcription factor (ATF)/cAMP-responsive element-binding protein (CREB) transcription factor (TF) family, ATF3, in thyroid cancer. Methods: Data from 80 patients with papillary thyroid cancer (PTC) in the First Affiliated Hospital of Sun Yat-sen University and 510 PTC samples in The Cancer Genome Atlas thyroid cancer database were utilized for gene expression and prognosis analyses. The survival data were analyzed by Kaplan-Meier curves and Cox regression with adjustment for age, sex, multilocality, extrathyroidal extension, lymph metastases, and history of neoadjuvant treatment. DNA methylation was analyzed by methylation-specific polymerase chain reaction (PCR) and bisulfite sequencing PCR. TFs binding to ATF3 promoter were identified by DNA pull-down combined with mass spectrum assay, and confirmed by quantitative PCR (qPCR), luciferase reporter assay, and chromatin immunoprecipitation (ChIP)-qPCR. We conducted functional assays in vitro and in a xenograft mouse model to evaluate the function of ATF3 in thyroid cancer. Integrated analyses based on RNA sequencing, ChIP-seq, and CUT&Tag assays were performed to explore the mechanisms underlying the function of ATF3. Results: ATF3 was significantly downregulated in PTC and patients with low ATF3 expression had reduced progression-free survival (adjusted hazard ratio = 0.50 [CI 0.26-0.98], p = 0.043). DNA hypermethylation in ATF3 promoter disrupted the binding of SP1 and MYC-MAX, leading to inactivation of the gene. ATF3 functioned as a TSG by inhibiting the proliferation and mobility of thyroid cancer cells. And ATF3 regulated the expression of a number of genes by binding to the regulatory elements of them, particularly for genes in MAPK and PI3K/AKT pathways. Among these target genes, filamin C was positively regulated by ATF3 and associated with a more favorable thyroid cancer prognosis, while dual specificity phosphatase 10, fibronectin-1, tenascin C, and CREB5 were negatively regulated by ATF3 and associated with a poorer prognosis. Conclusions: We observed that the promoter DNA hypermethylation decreased the expression of ATF3, which in turn promoted the progression of thyroid cancer, at least partially, by directly regulating prognosis-related genes in the MAPK and PI3K/AKT pathways.

Knockdown of long non-coding RNA SNHG3 inhibits proliferation, migration and invasion of human thyroid cancer via miR-339-5p/GPR62 axis

Previous studies have implicated SNHG3, a long non-coding RNA, in various human cancers, suggesting its oncogenic role. However, its specific involvement in thyroid cancer and the underlying molecular mechanisms remain unclear. Therefore, this study aims to elucidate the role of SNHG3 in human thyroid cancer and its interaction with the miR-339-5p/GPR62 axis. Understanding these mechanisms could provide insights into potential therapeutic targets for managing thyroid cancer. Results revealed significant upregulation of SNHG3 in human thyroid cancer tissues and cell lines. Knockdown of SNHG3 significantly suppressed proliferation, migration and invasion of CUTC5 and IHH-4 thyroid cancer cells. Knockdown of SNHG3 induces apoptosis in CUTC5 and IHH-4 cells and also inhibits the growth of xenografted tumors in vivo. Different in vitro assays revealed the interaction of SNHG3 with microRNA-339-5p (miR-339-5p) in thyroid cancer cells. Expression of miR-339-5p was significantly downregulated in thyroid cancer tissues and cell lines. However, the knockdown of SNHG3 caused significant upregulation of miR-339-5p. Interestingly, overexpression of miR-339-5p exerted tumor-suppressive effects in CUTC5 and IHH-4 cells via post-transcriptional suppression of GPR62. Knockdown of GPR62 significantly inhibited the proliferation, migration and invasion of CUTC5 and IHH-4 cells. Nonetheless, inhibition of miR-339-5p or overexpression of GPR62 avoids the growth inhibitory effects of SNHG3 knockdown in CUTC5 and IHH-4 cells. Results indicated that SNHG3 exerts oncogenic molecular function in thyroid cancer via miR-339-5p/GPR62 axis and may act as a therapeutic target for its management.

Construction and validation of a PANoptosis-related lncRNA signature for predicting prognosis and targeted drug response in thyroid cancer.

Thyroid cancer (TC) is the most prevalent malignancy of the endocrine system. PANoptosis, a newly discovered cell death pathway, is of interest in tumor research. However, the relationship between PANoptosis-related lncRNAs (PRlncRNAs) and TC remains unclear. The study aimed to develop a prognostic model based on PRlncRNAs in TC. Gene expression data of PANoptosis-associated genes and clinical information on TC from The Cancer Genome Atlas (TCGA) database were analyzed by Pearson correlation analysis, univariate/multivariate Cox analysis, and Lasso Cox regression analysis. A PRlncRNA signature was constructed and used to develop a nomogram to predict overall survival (OS). We further explored the correlation between the risk score and tumor immune microenvironment, immune checkpoints, and drug sensitivity. Moreover, we verified the expression and biological function of lncRNAs in TC cell lines. Finally, seven PRlncRNAs were used to construct a prognostic model for predicting the OS of TC patients. We found that the risk score was associated with the tumor microenvironment (TME) and the expression of critical immune checkpoints. In addition, we screened for drugs that high- or low-risk TC groups might be sensitive to. Quantitative real-time polymerase chain reaction (qRT-PCR) results showed differential expression of four PRlncRNAs (GAPLINC, IDI2-AS1, LINC02154, and RBPMS-AS1) between tumor and normal tissues. Besides, a GEO database (GSE33630) was used to verify the expression differences of PRLncRNAs in THCA tissues and normal tissues. Finally, RBPMS-AS1 was found to inhibit the proliferation and migration of TC cells. In conclusion, we developed a PANoptosis-related lncRNA prognostic risk model that offers a comprehensive understanding of TME status in patients with TC and establishes a foundation for the choice of sensitive medications and immunotherapy.

Proliferation and migration of ML1 follicular thyroid cancer cells are inhibited by IU1 targeting USP14: role of proteasome and autophagy flux.

USP14 is a deubiquitinating enzyme involved in protein degradation by interacting with the proteasome and removal of poly-ubiquitin chains on target proteins. USP14 can influence cellular processes such as cell survival, DNA repair, ER stress, endocytosis, and the inflammatory response. USP14 further plays a role in tumor growth, and the inhibition of USP14 by compounds such as IU1 may affect cancer cell migration and invasion. Here we have studied the mechanisms for the action of IU1 in ML1 follicular thyroid cancer cells, comparing them with control, primary thyroid cells. Treatment with IU1 reduced proliferation of ML1 cells in a concentration-dependent manner, and more prominently than in control cells. IU1 decreased basal migration of ML1 cells, and after stimulation of cells with the bioactive compound, sphingosine-1-phosphate. The sphingosine-1-phosphate receptor 3 was increased in ML1 cells as compared with control thyroid cells, but this was not influenced by IU1. Further studies on the mechanism, revealed that IU1 enhanced the proteasome activity as well as LC3B-dependent autophagy flux in ML1 cells with an opposite effect on control thyroid cells. This indicates that IU1 elicits a cell-type dependent autophagy response, increasing it in ML1 cancer cells. The IU1-mediated stimulation of autophagy and proteasomes can likely contribute to the reduced cell proliferation and migration observed in ML1 cells. The precise set of proteins affected by IU1 in ML1 thyroid and other cancer cells warrant further investigations.

Deltex E3 ubiquitin ligase 4 promotes thyroid cancer progression through stearoyl-CoA desaturase 1.

In this study, we aimed to explore the molecular role of Deltex E3 ubiquitin ligase 4 (DTX4) in thyroid cancer (TC) both in vitro and in vivo. The expression level of DTX4 in TC tissues was compared using The Cancer Genome Atlas (TCGA) database. We subsequently evaluated cell proliferation and migration in DTX4 knock down or DTX4 overexpression TC cell lines (TPC-1 and K1) by CCK-8, cell colony formation, and transwell assays. RNA sequencing and KEGG analysis were employed to identify potential genes that interact with DTX4. Our results showed that DTX4 was expressed at higher levels in both TC tissues and cells compared to normal controls. Knock down of DTX4 expression significantly inhibited TC cell progression in vitro. Furthermore, knockdown of endogenous DTX4 by shDTX4 markedly abrogated tumor growth, with significantly smaller tumor size and lower tumor weight in the shDTX4 group compared to the shCtrl group. Conversely, overexpression of DTX4 enhanced TC cell proliferation and migration. Through RNA sequencing, we identified 590 Differentially Expressed Genes (DEGs), with stearoyl-CoA desaturase 1 (SCD) ranking as the top gene. A positive correlation between DTX4 and SCD was observed in TC samples. Additionally, treatment with an SCD inhibitor, A939572, significantly rescued the enhanced growth effect induced by DTX4 overexpression. In conclusion, this study demonstrated that DTX4 promotes TC progression through SCD, indicating that the DTX4/SCD axis could be a promising target for TC therapy.

Association between thyroid stimulating hormone levels and papillary thyroid cancer risk: A meta-analysis.

High thyroid stimulating hormone (TSH) levels may stimulate papillary thyroid cancer (PTC) cell proliferation; however, the relationship between TSH levels and PTC risk remains controversial. We aim to ascertain the association through a meta-analysis. Literature searches were conducted in PubMed, Embase, and Web of Science databases. After literature screening, the methodological quality was assessed using the Newcastle-Ottawa Scale and Agency for Healthcare Research and Quality methods. Cochran's Q and I 2 tests were used to evaluate heterogeneity in the meta-analysis. Egger's test was applied to assess publication bias. A total of 12 eligible studies were included in this meta-analysis; all were of moderate and high methodological quality. The pooled results suggested that increased TSH levels were significantly associated with PTC risk; however, the included studies were significantly heterogeneous. Stratification analysis indicated that the heterogeneity might be from the area or type of control. Although significant publication bias existed among the studies, the trim-and-fill method and sensitivity analysis revealed that the combined results were stable and robust. TSH levels are significantly associated with the PTC risk; however, more high-quality studies in large sample sizes are recommended to verify the extrapolation of these findings.

MEX3A induces the development of thyroid cancer via targeting CREB1.

Thyroid cancer is a prevalent form of endocrine cancer, and its global incidence has been steadily increasing. MEX3A is a protein that is known to be highly expressed in various human malignant tumors, including thyroid cancer, and it has been linked to patient prognosis. However, the molecular mechanisms underlying MEX3A's tumorigenic capabilities in thyroid cancer are not fully understood. In this study, we aimed to investigate the role of MEX3A in thyroid cancer. We confirmed that MEX3A was overexpressed in both thyroid cancer tissues and cell lines. Additionally, we found a positive correlation between high levels of MEX3A and the AJCC stage. To further understand the functional significance of MEX3A in thyroid cancer, we depleted MEX3A expression in B-CPAP and TPC-1 cells. Interestingly, we observed a significant reduction in thyroid cancer cell proliferation and migration, as well as ameliorated cell apoptosis and arrested tumor growth upon MEX3A depletion. These findings strongly suggested that MEX3A played a critical role in the development of thyroid cancer. Furthermore, our study uncovered an important interaction between MEX3A and CREB1 (cAMP response element-binding protein 1). The interaction between MEX3A and CREB1 appeared to contribute to the tumor-promoting effects of MEX3A in thyroid cancer by directly targeting CREB1. Silencing CREB1 was observed to alleviate the malignant phenotypes promoted by MEX3A in thyroid cancer cells. Together, this study highlighted the importance of the MEX3A-CREB1 interaction in thyroid cancer development and suggested the therapeutic potential of targeting MEX3A for the treatment of this disease.

Jagged 1 Regulates The Proliferation and Metastasis of Human MDA-T68 Thyroid Cancer Cells.

The current study evaluated the expression profile and explored the therapeutic implications of Jagged 1 in human thyroid cancer. This experimental study was conducted in 60 paired specimens of papillary thyroid and adjacent normal tissues. Gene expression was determined by quantitative real time polymerase chain reaction (qRT-PCR) and western blotting. Transfection of cancer cells was performed by using Lipofectamine 2000. The cell proliferation of PTC cells was estimated by MTT assay. Clonogenic assay was performed for analysis of colony forming potential of cancer cells. The apoptosis of PTC cells was studied by using AO/EB and Annexin V-FITC/PI staining methods. Flow cytometry was done to analyze the cell cycle phase distribution of cancer cells. Migration and invasion PTC cells were determined respectively with the wound-healing and transwell assays. The impact of Jagged 1 silencing was investigated in vivo in a xenografted mice model followed by Immunohistochemistry (IHC) analysis. We found significant (P<0.05) upregulation of Jagged 1 in human thyroid cancer. Silencing of Jagged 1 caused significant (P<0.05) reduction in proliferation and colony formation of MDA-T68 cells. The inhibitory effects of Jagged 1 silencing were found to be due to the induction of apoptosis. We also found enhancement of Bax and repression of Bcl-2 protein levels in MDA-T68 cells. Wound healing assay indicated significant (P<0.05) inhibition of cell migration of MDA-T68 thyroid cancer cells. Additionally, we found that invasion of the thyroid cancer cells was reduced by 55% upon silencing of Jagged 1. Moreover, Jagged 1 silencing was found to cause inhibition of the Notch intracellular domain (NICD) and Notch target gene, Hes-1 expression. Finally, Jagged 1 silencing inhibited the xenografted tumors in vivo. The findings suggest that Jagged 1 regulates the development of thyroid cancer that may act as a therapeutic target for managing thyroid cancer.

P18INK4C and BRCA1 inhibit follicular cell proliferation and dedifferentiation in thyroid cancer

ABSTRACT Only 3% of thyroid cancers are medullary thyroid carcinomas (MTCs), the rest are follicular epithelial cell derived non-MTCs (NMTCs). A dysfunctional INK4-CDK4-RB pathway is detected in most of NMTCs. DNA repair defects and genome instability are associated with NMTC dedifferentiation and aggressiveness. Whether inactivation of the INK4-CDK4-RB pathway induces NMTCs and how differentiation of NMTC cells is controlled remain elusive. In this study, we generated p18Ink4c and Brca1 singly and doubly deficient mice as well as p16Ink4a and Brca1 singly and doubly deficient mice. By using these mice and human thyroid carcinoma cell lines, we discovered that loss of p18Ink4c, not p16Ink4a, in mice stimulated follicular cell proliferation and induced NMTCs. Depletion of Brca1 alone or both p16Ink4a and Brca1 did not induce thyroid tumor. Depletion of Brca1 in p18Ink4c null mice results in poorly differentiated and aggressive NMTCs with epithelial-mesenchymal transition (EMT) features and enhanced DNA damage. Knockdown of BRCA1 in thyroid carcinoma cells activated EMT and promoted tumorigenesis whereas overexpression of BRCA1 inhibited EMT. BRCA1 and EMT marker expression were inversely related in human thyroid cancers. Our finding, for the first time, demonstrates that inactivation of INK4-CDK4-RB pathway induces NMTCs and that Brca1 deficiency promotes dedifferentiation of NMTC cells. These results suggest that BRCA1 and p18INK4C collaboratively suppress thyroid tumorigenesis and progression and CDK4 inhibitors will be effective for treatment of INK4-inactivated or cyclin D-overexpressed thyroid carcinomas.

PLS3 promotes papillary thyroid carcinoma progression by activating the Notch signaling pathway.

Thyroid cancer is the most common endocrine malignancy worldwide. Although significant progress has been made in understanding the genetic and molecular alterations that drive thyroid cancer, the mechanisms underlying thyroid tumor progression remain unclear. In this study, we explored the involvement of Plastin-3 (PLS3) in the progression of papillary thyroid cancer and elucidated the underlying molecular mechanisms. We first analyzed clinical samples from papillary thyroid cancer patients and found that PLS3 expression was significantly upregulated in tumor tissues compared to adjacent normal tissues. Moreover, high PLS3 expression was associated with advanced tumor stage and poor prognosis. Further in vitro and in vivo experiments showed that PLS3 could promote the proliferation, migration, and invasive behavior of papillary thyroid cancer cells, while PLS3 knockdown suppressed these processes. Mechanistically, we found that PLS3 promoted papillary thyroid cancer progression by activating the Notch signaling pathway. Specifically, PLS3 upregulated the expression of Notch receptors (Notch1) and downstream target gene (Hes1) in papillary thyroid cancer cells. In summary, our findings collectively indicate that PLS3 plays a pivotal role in driving the progression of papillary thyroid cancer and holds promise as a viable therapeutic target for the treatment of this disease.

Pleckstrin homology and RhoGEF domain containing G4 (PLEKHG4) leads to the activation of RhoGTPases promoting the malignant phenotypes of thyroid cancer.

Thyroid cancer (TC) is one of the most common endocrine system cancers, and its incidence is elevating. There is an urgent need to develop a deeper understanding of TC pathogenesis and explore new therapeutic target for its treatment. This study aimed to investigate the effects of pleckstrin homology and RhoGEF domain containing G4 (PLEKHG4) on the progression of TC. Herein, 29 pairs of TC and adjacent tissues were used to assess the expression of PLEKHG4. A xenograft model of mouse was established by subcutaneously injected with TC cells. Lung metastasis model was established through left ventricular injection. The results revealed that PLEKHG4 was up-regulated in human TC tissues. PLEKHG4 level was correlated with clinicopathological parameters of TC patients. In vitro assays revealed that PLEKHG4 promoted TC cell proliferation, migration, invasion, and epithelial-mesenchymal transformation. Knockdown of PLEKHG4 led to the opposite effects, and the loss of PLEKHG4 enhanced the apoptosis ability and inhibited the stemness properties of TC cells. These findings were further confirmed by the in vivo growth and lung metastasis of TC tumor. Mechanistically, PLEKHG4 promoted the activation of RhoGTPases RhoA, Cdc42, and Rac1. The inhibitors of these RhoGTPases reversed the PLEKHG4-induced malignant phenotypes. Additionally, ubiquitin-conjugating enzyme E2O (UBE2O), a large E2 ubiquitin-conjugating enzyme acted as an ubiquitin enzyme of PLEKHG4, facilitated its ubiquitination and degradation. In conclusion, PLEKHG4, regulated by UBE2O, promoted the thyroid cancer progression via activating the RhoGTPases pathway. UBE2O/PLEKHG4/RhoGTPases axis is expected to be a novel a therapeutic target for TC treatment.

PLA2R1 Inhibits Differentiated Thyroid Cancer Proliferation and Migration via the FN1-Mediated ITGB1/FAK Axis.

PLA2R1 is a novel gene that is aberrantly expressed in a variety of malignancies. However, the role and mechanism of PLA2R1 in thyroid cancer has not been elucidated. We aimed to uncover the underlying mechanism of PLA2R1 in thyroid cancer. We collected 115 clinical specimens, including 54 tumor tissues and 61 para-cancerous tissues, who underwent surgical treatment at Shanghai Tenth Hospital. Immunohistochemical staining was used to evaluate PLA2R1 expression in differentiated thyroid cancer (DTC) tissues. The thyroid cancer cell lines 8505c and FTC133 transfected with PLA2R1 overexpression or knockdown plasmids were used for CCK8 assays and a wound healing assay. Next, we conducted coimmunoprecipitation (Co-IP) experiments and western blotting to explore the underlying mechanism of PLA2R1 in regulating the growth of thyroid cancer. We discovered that the expression of PLA2R1 was lower in the tumor tissues than in para-cancerous tissues (χ2 = 37.0, p < 0.01). The overexpression of PLA2R1 significantly suppressed thyroid cancer cell proliferation and migration, and both of these effects were partially attenuated by the knockdown of PLA2R1. Furthermore, the in vivo growth of DTC could be alleviated by the knockdown of PLA2R1. The mechanistic study revealed that PLA2R1 competed with FN1 for binding to ITGB1, inhibiting the FAK axis and epithelial-mesenchymal transition (EMT). We speculate that PLA2R1 might be a promising marker and a novel therapeutic target for thyroid cancer.

The Role of MMP-9 and MMP-9 Inhibition in Different Types of Thyroid Carcinoma.

Matrix metalloproteinase-9 (MMP-9), one of the most investigated and studied biomarkers of the MMPs family, is a zinc-dependent proteolytic metalloenzyme whose primary function is degrading the extracellular matrix (ECM). It has been proved that MMP-9 expression elevates in multiple pathological conditions, including thyroid carcinoma. MMP-9 has a detectable higher level in malignant or metastatic thyroid tumor tissues than in normal or benign tissues and acts as an additional marker to distinguish different tumor stages because of its close correlations with clinical features, such as lymph node metastasis, TNM stage, tumor size and so on. Natural and non-natural MMP-9 inhibitors suppress its expression, block the progression of diseases, and play a role in therapy consequently. MMP-9 inhibitory molecules also assist in treating thyroid tumors by suppressing the proliferation, invasion, migration, metastasis, viability, adhesion, motility, epithelial-mesenchymal transition (EMT), and other risk factors of different thyroid cancer cells. In a word, discovering and designing MMP-9 inhibitors provide great therapeutic effects and promising clinical values in various types of thyroid carcinoma.