Papillary Thyroid Carcinoma Cell Research Articles

METTL3-mediated m6A Modification of hsa_circ_0131922 Attenuates the Progression of Papillary Thyroid Cancer by Regulating the p53 Pathway.

This study aimed to confirm the regulatory role and mechanism of circular RNA (circRNA) hsa_circ_0131922 in Papillary Thyroid Carcinoma (PTC) progression. Accumulating evidence suggests that N6-methyladenosine (m6A)-modified circular RNAs (circRNAs) perform pivotal functions in various malignancies. However, the specific role of the m6A modification of circRNA mediated by METTL3 in Papillary Thyroid Carcinoma (PTC) remains undocumented. In this work, we aimed to examine the molecular mechanisms of a novel m6Amodified circRNA, hsa_circ_0131922, in PTC progression. Potential circRNA was identified from GEO datasets. The RNA or protein levels of hsa_circ_0131922, METTL3, p53, and p21 were evaluated by qRT-PCR or western blot assays. The various cellular functions were checked by CCK8, wound healing, transwell, and xenograft tumor assays. MeRIP-qPCR was performed to observe the METTL3-mediated m6A modification of hsa_circ_0131922. Furthermore, the interactions between hsa_circ_0131922 and METTL3 in PTC were analyzed by bioinformatics analysis and various rescue experiments. The levels of hsa_circ_0131922 were markedly downregulated in PTC tissues and cell lines. In addition, the lower hsa_circ_0131922 levels correlated with poor prognosis in PTC patients. The hsa_circ_0131922 overexpression reduced the malignant phenotypes of PTC cells and activated the p53/p21 pathway. Bioinformatic analysis showed the m6A-modified sites of hsa_circ_0131922, and a positive correlation between hsa_circ_0131922 and METTL3. Moreover, overexpression of METTL3 increased the levels of m6A modification of hsa_circ_0131922. Mechanistically, the anti-tumor effects of hsa_circ_0131922 overexpression have been found to be partially reversed by silencing METTL3 in vivo and in vitro. The results have demonstrated m6A-modified hsa_circ_0131922 by METTL3 to attenuate the progression of PTC by regulating the p53 pathway. Therefore, hsa_circ_0131922 could be a predictive prognostic biomarker and therapeutic target for PTC.

Elevated Cancer-Associated Hyaluronan Correlates With Diagnosis and Lymph Node Metastasis of Papillary Thyroid Cancer

The glycosaminoglycan hyaluronan (HA) plays an important role in tumor progression. However, its biological and clinical significance in papillary thyroid cancer (PTC) remains unknown. Immunohistochemistry was performed to examine HA expression in tissues from PTC patients. Two PTC cell lines were treated with HA synthesized inhibitor against HA production to assess its function. Serum HA levels from 107 PTC patients, 30 Hashimoto thyroiditis patients, and 45 normal controls (NC) were measured by chemiluminescence immunoassay. HA levels in fine needle aspiration (FNA) washouts obtained from thyroid nodules and lymph nodes (LNs) were measured by chemiluminescence immunoassay. Area under the curve (AUC) was computed to evaluate HA’s clinical value. HA was highly expressed in PTC. Reducing HA production significantly inhibited PTC cell proliferation and invasion. Importantly, serum HA levels in PTC were significantly higher than those in NCs and Hashimoto thyroiditis and allowed distinguishing of thyroid cancers from NCs with high accuracy (AUC = 0.782). Moreover, elevated serum HA levels in PTC correlate with LN metastasis. HA levels in FNA washouts from PTC patients were significantly higher than those in benign controls, with a high AUC value (0.8644) for distinguishing PTC from benign controls. Furthermore, HA levels in FNA washouts from metastatic LN were significantly higher than those in nonmetastatic LN, with a high AUC value (0.8007) for distinguishing metastatic LNs from nonmetastatic LNs. HA levels in serum and FNA washout exhibited a potential significance for PTC diagnosis and an indicator for LN metastasis in patients with PTC.

The common pathogenesis of nodular goiter in both sexes: An exploration into gene expression and signaling pathways

The past few years have witnessed an increasing incidence of nodular goiter (NG), with a well-documented higher prevalence in females than males. This gender disparity has led research to focus primarily on female subjects, potentially overlooking common pathogenic mechanisms in both sexes. In this study, we investigated the shared pathogenesis of NG in males and females. Utilizing a rat model and RNA sequencing, we identified differentially expressed genes associated with the disease. We further validated these findings in normal human thyroid cells and human papillary thyroid cancer cells. A randomized experiment was conducted with equal numbers of male and female rats divided into control and NG model groups. The NG model was established using propylthiouracil and various assessments such as thyroid ultrasonography, thyroid index, thyroid function, and thyroid histology were performed. Transcriptome analysis revealed numerous upregulated and downregulated genes in both male and female model groups. Key genes like KDR, FLT1, PDGFB, and CAV1, and pathways including PI3K-Akt, MAPK, Ras, fluid shear stress and atherosclerosis, calcium signaling, and Rap1 signaling pathways were linked with the disease. Western blot and immunofluorescence analysis confirmed these findings, which were further supported by cell-based experiments. In conclusion, our findings suggest that abnormal expression of specific genes and pathways leading to irregular cell growth, blood vessel formation, and inflammation may be common factors in the pathogenesis of NG in both males and females.

A Specificity Protein 1 assists the progression of the papillary thyroid cell line by initiating NECTIN4.

Papillary thyroid cancer (PTC) is one of the subtypes of thyroid cancer with increasing incidence worldwide, but the molecular mechanism is still unclear. Papillary thyroid cancer (PTC) is one of the subtypes of thyroid cancer with increasing incidence worldwide, but the molecular mechanism is still unclear. Studies have indicated that nectin cell adhesion molecule 4 (NECTIN4) was an oncogene and played an important role in the development and progression of PTC. Meanwhile, specificity protein 1 (SP1) expresses many important oncogenes and tumor suppressor genes. However, the relationship between NECTIN4 and SP1 in regulating PTC growth is unclear. In the present study, reverse transcription PCR was utilized to detect the mRNA expression of NECTIN4 and SP1 in thyroid cancer cell lines and normal thyroid cell lines. Chromatin immunoprecipitation assays and luciferase reporter assays were used to study whether SP1 could bind to the promoter region of NECTIN4 and activate its transcription. The biological functions of SP1 correlated with NECTIN4 were also performed in TPC-1 and KTC1 cell lines. The study revealed that the mRNA expression level of SP1 and NECTIN-4 showed a positive correlation and were upregulated in PTC cell lines. Moreover, the results of ChIP and luciferase reporter assays showed that SP1 could bind to the NECTIN4 promoter regions and activate the transcriptional level of NECTIN4. The experiments in vitro showed that SP1 could promote cell proliferation, colony formation, migration, and invasion by regulating NECTIN4 in PTC cells. In conclusion, our study, for the first time, demonstrated that SP1 could control the transcriptional regulation of NECTIN4 and accelerate the growth of PTC, which may provide a new potential therapeutic target for PTC patients.

Hsa_circ_0101050 regulated by ZC3H13 enhances tumorigenesis in papillary thyroid cancer via m6A modification

While the regulatory roles of circular RNAs (circRNAs) and zinc finger CCCH-type containing 13 (ZC3H13) were previously reported in various human cancers, the mechanisms underlying their interaction in papillary thyroid cancer (PTC) remain unclear. We aimed to determine the role of hsa_circ_0101050 and its regulatory relationship with ZC3H13 in PTC. The expression levels of hsa_circ_0101050 and ZC3H13 were determined in tumor samples and adjacent normal tissues from 46 patients with PTC and in two PTC cell lines (IHH-4 and PTC-1) using quantitative reverse transcription–polymerase chain reaction. The roles of hsa_circ_0101050 and ZC3H13 in cell viability, wound healing, and migration were determined using knockdown and overexpression approaches in PTC cell lines, and a xenograft model in nude mice was used to determine their role in vivo. Methylated RNA immunoprecipitation assay was used to analyze N6-methyladenosine (m6A) modification of hsa_circ_0101050 by ZC3H13. We found hsa_circ_0101050 overexpression and ZC3H13 downregulation in PTC samples and PTC cell lines. In PTC cell lines, silencing hsa_circ_0101050 reduced cell viability and migration whereas its overexpression promoted an aggressive PTC phenotype. ZC3H13 increased the m6A modification of hsa_circ_0101050 and repressed its expression. ZC3H13 overexpression inhibited PTC cell viability, migration, and invasion, which were reversed in cells overexpressing hsa_circ_0101050. Taken together, these results suggested that the downregulation of hsa_circ_0101050 mediated by ZC3H13 through m6A modification contributed to its oncogenic effect in PTC development, revealing the ZC3H13–m6A–hsa_circ_0101050 as a potential therapeutic target in PTC.

Papillary Thyroid Cancer, Small Cell Lung Cancer, and Parathyroid Adenoma Synchronously Visualized on 99m Tc-MIBI SPECT/CT in a Patient With Hyperparathyroidism : Comparison With 18 F-FDG PET/CT.

99m Tc-MIBI scintigraphy is a nuclear medicine imaging modality commonly used for the preoperative localization of parathyroid adenomas in patients with hyperparathyroidism. In addition, 99m Tc-MIBI can also be used for imaging various tumors due to its unique mechanism of intracellular accumulation. Here, we introduced a case of a single 99m Tc-MIBI SPECT/CT simultaneously visualized two different malignant tumors, such as papillary thyroid cancer and small cell lung cancer, along with a parathyroid adenoma in a patient with hyperparathyroidism. The clinical usefulness of 99m Tc-MIBI SPECT/CT was also explored by comparing it with 18 F-FDG PET/CT among the three tumors.

Occupational papillary thyroid carcinoma and basal cell carcinoma coexistence: a case report

Occupational cancers are cancers that result from exposure to carcinogens at work. Diagnosing occupational cancer expresses great importance in terms of public health. Because all occupational cancers are preventable as other occupational diseases. A detailed occupational history and careful questioning of exposure factors enable early diagnosis and prevention of occupational cancer. It is known that thyroid and skin cancers may occur due to occupational exposures. In this report, the coexistence of occupational thyroid cancer and occupational basal cell skin carcinoma is presented.

HYPOXIA induces lncRNA HOTAIR for recruiting RELA in papillary thyroid cancer cells to upregulate miR-181a and promote angiogenesis.

Papillary thyroid carcinoma (PTC) is one of the most common subtypes of thyroid carcinoma. Exosomal miR-181a plays an important role in the development of PTC. This study examined the regulatory mechanism of miR-181a under conditions of hypoxia and its impact on angiogenesis. A ribonucleoprotein immunoprecipitation (RIP) experiment was conducted to verify the interaction between HOTAIR and RELA. The relationship between RELA and the miR-181a promoter was detected by ChIP-qPCR. Short hairpin (sh) RNA was designed to knock down HOTAIR in TPC cells. The underlying mechanism of miR-181a was verified by use of dual-luciferase assays and rescue experiments. The regulatory effect of GATA6 on angiogenesis was studied using CCK8, EdU, Transwell, and western blot assays. A RIP assay showed that HOTAIR could bind to RELA under hypoxic conditions. ChIP-qPCR and dual luciferase assays showed RELA could interact with the miR181a promoter and upregulate miR-181a. Knockdown of HOTAIR downregulated miR-181a in TPC-1 cells, and the downregulation could be rescued by RELA overexpression. MiR-181a downregulated GATA6 in HUVEC cells. Overexpression of GATA6 inhibited HUVEC proliferation, migration, tube formation, and EGFR expression. Exosomal miR-181a promoted angiogenesis by downregulating GATA6 expression. HOTAIR activated RELA to upregulate miR-181a during hypoxia. Exosomal miR-181a promotes tumor angiogenesis by downregulating GATA6.

Papillary Thyroid Cancer Remodels the Genetic Information Processing Pathways.

The genetic causes of the differentiated, highly treatable, and mostly non-fatal papillary thyroid cancer (PTC) are not yet fully understood. The mostly accepted PTC etiology blames the altered sequence or/and expression level of certain biomarker genes. However, tumor heterogeneity and the patient's unique set of favoring factors question the fit-for-all gene biomarkers. Publicly accessible gene expression profiles of the cancer nodule and the surrounding normal tissue from a surgically removed PTC tumor were re-analyzed to determine the cancer-induced alterations of the genomic fabrics responsible for major functional pathways. Tumor data were compared with those of standard papillary and anaplastic thyroid cancer cell lines. We found that PTC regulated numerous genes associated with DNA replication, repair, and transcription. Results further indicated that changes of the gene networking in functional pathways and the homeostatic control of transcript abundances also had major contributions to the PTC phenotype occurrence. The purpose to proliferate and invade the entire gland may explain the substantial transcriptomic differences we detected between the cells of the cancer nodule and those spread in homo-cellular cultures (where they need only to survive). In conclusion, the PTC etiology should include the complex molecular mechanisms involved in the remodeling of the genetic information processing pathways.

Columnar Cell Thyroid Carcinoma: A Heterogeneous Entity Demonstrating Overlap Between Papillary Thyroid Carcinoma and Follicular Neoplasms.

Columnar cell papillary thyroid carcinoma (CC-PTC) is a morphologic subtype of papillary thyroid carcinoma with a variable prognosis. It is characterized by neoplastic thyroid follicular-derived cells with pseudostratified columnar morphology arranged in papillary or follicular structures with supranuclear or subnuclear vacuoles. The molecular profile of this subtype has only recently come under scrutiny, with mixed results. The aim of this study is to further explore the morphologic, immunohistochemical, and genetic profile of CC-PTC, as well as to correlate these features with clinical outcomes. CC-PTC cases were identified from 3 institutions. Immunohistochemistry (ER, CDX2) and molecular testing (DNA and RNA sequencing) were performed. Clinicopathologic parameters and patient outcomes were recorded. Twelve cases (2006-2023) were identified, all in adults (age 45-91). Two presented with disease outside the thyroid gland (neck and mediastinum) and two presented with distant metastasis. Four were high-grade differentiated thyroid carcinomas (necrosis or mitoses), one of which died of disease. Four were noninvasive or minimally invasive, one of which locally recurred. Three patients had lymph node metastases. ER and CDX2 were positive in 73% and 50%, respectively. Pathogenic mutations were found in TERT promoter (n = 3), RAS (n = 2), ATM, NOTCH1, APC, and ESR1, along with cases bearing AGK::BRAF fusion (n = 1), BRAF VE1 expression (n = 1), and NF2 loss (n = 1). This study represents the largest molecularly defined cohort of non-oncocytic thyroid carcinomas with columnar cell morphology. These tumors represent a genetically and behaviorally heterogeneous group of neoplasms, some of which have RAS-like or follicular neoplasm-like genetics, some of which have BRAF-p.V600E-like or classic papillary thyroid carcinoma-like genetics, and some of which remain unclear. Noninvasive or minimally invasive tumors showed an indolent course compared to those with angioinvasion, gross extrathyroidal growth, or high-grade morphology. Consideration could be given to reclassification of this neoplasm outside of the subtyping of papillary thyroid carcinoma in light of its genetic diversity, distinct morphology, and clinical behavior more closely aligned with follicular thyroid neoplasms.

CLIP170 inhibits the metastasis and EMT of papillary thyroid cancer through the TGF-β pathway.

Metastasis poses a significant challenge in combating tumors. Even in papillary thyroid cancer (PTC), which typically exhibits a favorable prognosis, high recurrence rates are attributed to metastasis. Cytoplasmic linker protein 170 (CLIP170) functions as a classical microtubule plus-end tracking protein (+TIP) and has shown close association with cell migration. Nevertheless, the specific impact of CLIP170 on PTC cells remains to be elucidated. Our analysis of the GEO and TCGA databases unveiled an association between CLIP170 and the progression of PTC. To explore the impact of CLIP170 on PTC cells, we conducted various assays. We evaluated its effects through CCK-8, wound healing assay, and transwell assay after knocking down CLIP170. Additionally, the influence of CLIP170 on the cellular actin structure was examined via immunofluorescence; we further investigated the molecular expressions of epithelial-mesenchymal transition (EMT) and the transforming growth factor-β (TGF-β) signaling pathways through Western blotting and RT-qPCR. These findings were substantiated through an in vivo nude mouse model of lung metastasis. We observed a decreased expression of CLIP170 in PTC in contrast to normal thyroid tissue. Functionally, the knockdown of CLIP170 (CLIP170KD) notably enhanced the metastatic potential and EMT of PTC cells, both in vitro and in vivo. Mechanistically, CLIP170KD triggered the activation of the TGF-β pathway, subsequently promoting tumor cell migration, invasion, and EMT. Remarkably, the TGF-β inhibitor LY2157299 effectively countered TGF-β activity and significantly reversed tumor metastasis and EMT induced by CLIP170 knockdown. In summary, these findings collectively propose CLIP170 as a promising therapeutic target to mitigate metastatic tendencies in PTC.

Network Pharmacological Analysis and Experimental Validation of the Effects of Silybin on Proliferation, Migration, and Immunotherapy of Papillary Thyroid Cancer.

The study aimed to use network pharmacology research and in vitro experiments to investigate the material basis and molecular mechanisms of silybin in the treatment of papillary thyroid carcinoma. Papillary thyroid cancer (PTC) has a decent prognosis; however, recurrence and metastasis are the leading causes of death in patients with PTC. A key research focus in thyroid cancer treatment is the inhibition of PTC proliferation, invasion, and migration. Silybin, the major active element in the traditional Chinese herb silymarin, has been used to treat a range of diseases, including cancer, but no study has been undertaken to determine whether it can help prevent PTC. In this study, we attempted to determine through network pharmacology and in vitro experiments if silybin inhibits the development of papillary thyroid cancer by inhibiting cell cycle and invasive migration. To predict the probable targets and underlying mechanisms of silybin against PTC, a network pharmacology research was performed. In vitro experiments were conducted to further evaluate silybin's anti-cancer properties and priority targets against PTC. The datasets revealed a total of 489 silybin targets acting on PTC, and functional enrichment analysis suggested that the target genes were enriched in functions and pathways related to PTC development, invasion, migration, and immunotherapy. By constructing these target PPI networks, the seven hub genes, fibronectin 1 (FN1), tissue inhibitor of metalloproteinases 1 (TIMP1), N-cadherin (CDH2), collagen type III alpha 1 chain (COL3A1), cyclin D1 (CCND1), AP-1 transcription factor subunit (JUN), and hepatocyte growth factor receptor (MET) were found. These hub genes were determined to be highly linked to a worse clinicopathological form, a higher risk of metastatic recurrence, and a worse prognosis of PTC. The common immunological checkpoint gene expression levels were positively correlated with the expression levels of the hub genes. Silybin decreased the proliferative and metastatic capacity of PTC cells, according to in vitro investigations. When PTC was treated with silybin, the FN1/AKT signaling pathway was blocked, CCND1 expression was reduced, and CDH2, Vimentin, Snail, Slug and PD-L1 expressions were dramatically reduced, while E-cadherin expression was significantly elevated. These findings provide preliminary evidence that silybin inhibits PTC cell proliferation, metastasis, and invasion by altering the FN1/AKT signaling pathway and inhibiting the EMT process. Silybin can reverse immunosuppression in papillary thyroid cancer by affecting immunological checkpoint gene expression levels. These studies provide a theoretical and experimental scientific basis for the potential anticancer effects of silybin on PTC.

SYVN1 modulates papillary thyroid carcinoma progression by destabilizing HMGB1

E3 ubiquitin ligase synoviolin (SYVN1) has been reported to participate in many human cancers. This study aimed to investigate SYVN1’s roles and molecular pathways in papillary thyroid cancer (PTC). The functions of SYVN1 in PTC were further analyzed using gain- and loss-of-function methods and numerous investigations in cellular function and molecular biology. The findings demonstrated that the overexpression of SYVN1 markedly suppressed the proliferation, migration, and invasion of PTC cell lines (NPA87 and TPC-1). We found that SYVN1 interacted with HMGB1 and promoted its ubiquitination and degradation. In addition, SYVN1 effectively impairs cell proliferation, migration, invasion, and the formation of tumor xenografts in mice models. However, this effect may be partly reversed by overexpressing HMGB1. Thus, SYVN1 may inhibit the proliferation, migration, and invasion of PTC cells by disrupting HMGB1. Consequently, SYVN1 might be considered a promising therapeutic target for PTC.

Circ-METTL15 stimulates the aggressive behaviors of papillary thyroid cancer cells by coordinating the miR-200c-3p/XIAP axis

Background and objective: Thyroid cancer is the most common malignant tumor in the endocrine system. Papillary thyroid carcinoma (PTC) accounts for the vast majority of cases in this cancer. Recently, the vital role of circular RNA (circRNA) has been acknowledged in various cancers. However, to date, few studies have examined the roles of circRNAs in PTC. Therefore, this research aimed at exploring the function and mechanism of circ-methyltransferase-like 15 (METTL15) in PTC cells.Methods: First, quantitative measurements of circ-METTL15, miR-200c-3p, and X-linked inhibitor of apoptosis protein (XIAP) in PTC cells were completed with reverse transcription-quantitative polymerase chain reaction or Western blot analysis. After the intervention of circ-METTL15, miR-200c-3p, or XIAP expression, cell counting kit-8 and colony formation assays were used to examine cell proliferation, flow cytometry was used to examine apoptosis, and Transwell assays were used to examine migration and invasion. The targeted binding sites between miR-200c-3p and circ-METTL15 or XIAP were predicted by starBase and then verified by dual luciferase reporter assay.Results: circ-METTL15 and XIAP were upregulated in the PTC cells, while miR-200c-3p was downregulated. Downregulating circ-METTL15 or upregulating miR-200c-3p prevented the PTC cells from proliferating, migrating, and invading, and stimulated cell apoptosis. miR-200c-3p was the downstream molecule of circ-METTL15, and XIAP was the direct target of miR-200c-3p. Forcing XIAP expression obstructed circ-METTL15 silencing to inhibit PTC cell activity.Conclusion: Circ-METTL15 stimulates the aggressive behaviors of papillary thyroid cancer cells by coordinating the miR-200c-3p/XIAP axis.

Extra-nuclear TERT counteracts oxidative stress and promotes progression in papillary thyroid carcinoma

The reactivation of TERT is associated with poor outcome in papillary thyroid cancer (PTC). Extra-telomeric functions of TERT were reported, with a protective role against oxidative stress (OS). The aim of the present study was to explore the extra-nuclear TERT localization in PTC and its role in cancer progression.TERT nuclear export under OS were analyzed in K1 PTC cell line. We investigated the role of different TERT localizations using specific TERT constructs that limit its localization to the nucleus or to the mitochondria. The effect of SRC kinase inhibitor PP2, which reduces TERT nuclear export, was investigated as well. Moreover, TERT localization was analyzed in 39 PTC tissues and correlated with the genetic profile and the level of OS, DNA damage and apoptosis in the tumors and with the clinical characteristics of the patients.We demonstrated that TERT is exported from the nucleus in response to OS induced either from H2O2 or the BRAF inhibitor PLX4720. We proved that extra-nuclear TERT reduces mitochondrial OS and induces mitochondrial fragmentation. Moreover, limiting mitochondrial TERT localization reduced proliferation, migration, AKT phosphorylation and glycolysis and increased DNA damage and p21 expression. Finally, in PTC tissues the fraction of mitochondrial/nuclear TERT resulted inversely correlated with OS and p21 expression and associated with tumor persistence.In conclusion, our data indicate that extra-nuclear TERT is involved in reducing the effect of excessive OS, thus promoting cancer cell survival. Extra-nuclear TERT may thus represent a marker of cancer progression and a possible therapeutic target in PTC.

CircPHGDH downregulation decreases papillary thyroid cancer progression through miR-122-5p/PKM2 axis

BackgroundAlthough papillary thyroid carcinoma (PTC) has a favorable prognosis, it could affect patient life quality and become a serious threat because of invasion and metastasis. Many investigations have suggested that circular RNAs (circRNAs) are involved in different cancer regulations. Nevertheless, circRNAs role in invasive PTC remains unclear.MethodsIn the present investigation, next-generation sequencing was applied to explore abnormal circRNA expression. The expression of circRNA phosphoglycerate dehydrogenase (circPHGDH) in PTC cell lines and tissues were examined. Then, we investigated regulatory mechanism and circPHGDH downstream targets using bioinformatics analysis and luciferase reporting analysis. Then transwell migration, Cell Counting Kit-8 (CCK8) and 5-ethynyl-2’-deoxyuridine (EdU) assays were used for cells migration and proliferation analysis. In vivo metastasis and tumorigenesis assays were also employed to evaluate the circPHGDH role in PTC.ResultsThe data showcased that circPHGDH expression increased in both PTC cell lines and tissues, which suggested that circPHGDH functions in PTC progression. circPHGDH downregulation suppressed PTC invasion and proliferation in both in vivo and in vitro experiments. Bioinformatics and luciferase reporter results confirmed that both microRNA (miR)-122-5p and pyruvate kinase M2 subtype (PKM2) were downstream targets of circPHGDH. PKM2 overexpression or miR-122-5p suppression reversed PTC cell invasion and proliferation post silencing circPHGDH by restoring aerobic glycolysis.ConclusionTaken together, our research found that circPHGDH downregulation reduced PTC progression via miR-122-5p/PKM2 axis regulation mediated by aerobic glycolysis.

Functional analysis of ESM1 by shRNA-mediated knockdown of its expression in papillary thyroid cancer cells.

Endothelial specific molecule-1 (ESM1) is implicated as an oncogene in multiple human cancers. However, the function of ESM1 in papillary thyroid cancer (PTC) is not well understood. The current study aimed to investigate the effect of ESM1 on the growth, migration, and invasion of PTC to provide a novel perspective for PTC treatment. The expression levels of ESM1 in PTC tissues form 53 tumor tissue samples and 59 matching adjacent normal tissue samples were detected by immunohistochemical analysis. Knockdown of ESM1 expression in TPC-1 and SW579 cell lines was established to investigate its role in PTC. Moreover, cell proliferation, apoptosis, wound healing, and transwell assays were conducted in vitro to assess cell proliferation, migration and invasion. The findings revealed that ESM1 expression was significantly higher in PTC tissues than that found in paraneoplastic tissues (P<0.0001). Knockdown of ESM1 expression inhibited the proliferation, migration, and invasion of TPC-1 and SW579 cells in vitro. Compared with the control group, the mRNA and protein levels of ESM1 in PTC cells were significantly reduced following knockdown of its expression (P<0.01). In addition, ESM1-knockdown cells indicated decreased proliferation and decreased migratory and invasive activities (P<0.01, P<0.01, P<0.001, respectively). ESM1 was identified as a major gene in the occurrence and progression of PTC, which could increase the proliferation, migration, and invasion of PTC cells. It may be a promising diagnostic and therapeutic target gene.

Mcl-1 mediates intrinsic resistance to RAF inhibitors in mutant BRAF papillary thyroid carcinoma

Papillary thyroid carcinoma (PTC) is the most frequent form of thyroid cancer. PTC commonly presents with mutations of the serine/threonine kinase BRAF (BRAFV600E), which drive ERK1/2 pathway activation to support growth and suppress apoptosis. PTC patients often undergo surgical resection; however, since the average age of PTC patients is under 50, adverse effects associated with prolonged maintenance therapy following total thyroidectomy are a concern. The development of mutant-selective BRAF inhibitors (BRAFi), like vemurafenib, has been efficacious in patients with metastatic melanoma, but the response rate is low for mutant BRAF PTC patients. Here, we assay the therapeutic response of BRAFi in a panel of human PTC cell lines and freshly biopsied patient samples. We observed heterogeneous responses to BRAFi, and multi-omic comparisons between susceptible and resistant mutant BRAF PTC revealed overrepresented stress response pathways and the absence of compensatory RTK activation – features that may underpin innate resistance. Importantly, resistant cell lines and patient samples had increased hallmarks of failed apoptosis; a cellular state defined by sublethal caspase activation and DNA damage. Further analysis suggests that the failed apoptotic phenotypes may have features of “minority mitochondrial outer membrane permeabilization (MOMP)” – a stress-related response characterized by fragmented and porous mitochondria known to contribute to cancer aggressiveness. We found that cells presenting with minority MOMP-like phenotypes are dependent on the apoptotic regulator, Mcl-1, as treatment with the Mcl-1 inhibitor, AZD5991, potently induced cell death in resistant cells. Furthermore, PI3K/AKT inhibitors sensitized resistant cells to BRAFi; an effect that was at least in part associated with reduced Mcl-1 levels. Together, these data implicate minority MOMP as a mechanism associated with intrinsic drug resistance and underscore the benefits of targeting Mcl-1 in mutant BRAF PTC.

FLNA overexpression promotes papillary thyroid cancer aggression via the FAK/AKT signaling pathway.

Filamin A (FLNA) is a member of the filamin family and has been found to be critical for the progression of several cancers. However, its biological function in papillary thyroid cancer (PTC) remains largely unexplored. Data from The Cancer Genome Atlas (TCGA) databases were utilized to analyze the FLNA expression level and its influence on the clinical implications of patients with PTC. Gene Expression Omnibus (GEO) and qRT-PCR was used to verify the expression levels of FLNA in PTC. Kaplan-Meier survival analysis was conducted to evaluate the prognostic value of FLNA in PTC. Transwell assays and wound healing were performed to examine the biological function of FLNA knockdown in PTC cells. Gene set enrichment analysis (GSEA) and Western blotting were conducted to investigate the potential mechanisms underlying the role of FLNA in PTC progression. In addition, the relationship between FLNA expression and the tumor immune microenvironment (TME) in PTC was explored. FLNA was significantly upregulated in PTC tissues. High expression levels of FLNA was correlated with advanced TNM stage, T stage, and N stage, as well as poor disease-free interval (DFI) and progression-free interval (PFI) time in PTC patients. Moreover, we found that FLNA knockdown inhibited the migration and invasion of PTC cells. Mechanistically, FLNA knockdown inhibited epithelial-mesenchymal transition (EMT) in PTC and affected the activation of the FAK/AKT signaling pathway. In addition, FLNA expression was associated with TME in PTC. FLNA may be regarded as a new therapeutic target for PTC patients.

Tumor‑suppressive effects of Smad‑ubiquitination regulator 2 in papillary thyroid carcinoma.

Smad-ubiquitination regulator 2 (SMURF2) functions as a homolog of E6AP carboxyl terminus-type E3 ubiquitin ligase to regulate cell cycle progression and tumor growth factor expression. SMURF2 has been revealed to function as a tumor suppressor in a number of cancers; however, its function in papillary thyroid carcinoma (PTC) remains largely unknown. Therefore, the aim of the present study was to investigate the function of SMURF2 in PTC. Reverse transcription-quantitative PCR and western blotting were used to detect cellular expression of SMURF2 in vitro. After increasing or inhibiting the expression of SMURF2, MTT was used to detect the effect on tumor cell proliferation and Transwell assays were used to detect the effect on tumor cell migration and invasion. Finally, ELISA was used to detect the effects on glucose and glutamine metabolism in tumor cells and the findings revealed that SMURF2 was downregulated in PTC tissues. Moreover, SMURF2 inhibited the proliferation, invasion and migration of PTC cells, and promoted their apoptosis. Finally, SMURF2 inhibited cell glycolysis and glutaminolysis and affected metabolism in the PTC cell line, TPC-1. Thus, the findings of the present study suggest that SMURF2 may be a potential target in the treatment of PTC.