MAPK- and AKT-activated thyroid cancers are sensitive to group I PAK inhibition

TERT promoter mutations contribute to adverse clinical outcomes and poor prognosis in radioiodine refractory differentiated thyroid cancer

Telomerase reverse transcriptase promoter (TERTp) mutations are associated with non-radioiodine avidity. However, the role of these mutations in the clinical outcomes of patients with radioiodine-refractory differentiated thyroid cancer (RAIR-DTC) remains unknown. Herein, we aim to analyze gene mutations and clinical manifestations to verify TERTp's role in driving disease progression to RAIR-DTC and clinical outcomes. Next-generation sequencing data and clinical data were obtained from 243 patients with DTC. Of the 25 patients with TERTp mutations, 80% (20/25) had RAIR-DTC. RAIR-DTC was significantly less prevalent in patients with BRAFV600E (9/143, 6.3%) than those with both BRAFV600E and TERTp mutations (14/17, 82.4%). Patients with RAIR-DTC harboring both BRAFV600E and TERTp mutations were more likely to have > 3 distant metastatic sites (85.7%, 12/14) than those with BRAFV600E alone (33.3%, 3/9). Only one patient with both BRAFV600E and TERTp mutations had non-RAIR-DTC. The time from initial radioactive iodine therapy to RAIR-DTC diagnosis was significantly shorter in patients with TERTp mutations than in those without. Patients with BRAFV600E and TERTp mutations progressed faster to RAIR-DTC than those with BRAFV600E alone (p < 0.01). Our findings suggest that molecular testing for TERTp and other mutations like BRAFV600E may inform early diagnosis, prognosis, and treatment strategies before progression to RAIR-DTC.

Study on chemical profiling of bailing capsule and its potential mechanism against thyroiditis based on network pharmacology with molecular docking strategy

Bailing capsule (BLC), a drug that is clinically administered to modulate the autoimmune system, exhibits promising therapeutic potential in the treatment of thyroiditis. This study elucidates the chemical profile of BLC and its potential therapeutic mechanism in thyroiditis, leveraging network pharmacology and molecular docking techniques. Utilizing ultra-high-performance liquid chromatography coupled with linear trap-Orbitrap mass spectrometry (UHPLC-LTQ-Orbitrap MS), 58 compounds were identified, the majority of which were nucleosides and amino acids. Utilizing the ultra-high-performance liquid chromatography coupled with triple quadrupole tandem mass spectrometry (UHPLC QqQ MS/MS) strategy, 16 representative active components from six batches of BLCs were simultaneously determined. Network pharmacology analysis further revealed that the active components included 5'-adenylate, guanosine, adenosine, cordycepin, inosine, 5'-guanylic acid, and l-lysine. Targets with higher connectivity included AKT1, MAPK3, RAC1, and PIK3CA. The signaling pathways primarily focused on thyroid hormone regulation and the Ras, PI3K/AKT, and MAPK pathways, all of which were intricately linked to inflammatory immunity and hormonal regulation. Molecular docking analysis corroborated the findings from network pharmacology, revealing that adenosine, guanosine, and cordycepin exhibited strong affinity toward AKT1, MAPK3, PIK3CA, and RAC1. Overall, this study successfully elucidated the material basis and preliminary mechanism underlying BLC's intervention in thyroiditis, thus laying a solid basis for further exploration of its in-depth mechanisms.

Hypermethylation of microRNA-497-3p contributes to progression of thyroid cancer through activation of PAK1/β-catenin

MicroRNA-497 (miR-497) has been reported to be a tumor-suppressive miRNA in thyroid cancer (TC), yet the mechanism is not clearly defined. In this study, we aim to determine the mechanism by which miR-497-3p affects the progression of TC. After characterization of low miR-497-3p expression pattern in TC and normal tissues, we assessed the correlation between miR-497-3p expression and clinicopathological features of TC patients. Its low expression shared associations with advanced tumor stage and lymph node metastasis. ChIP and methylation-specific PCR provided data showing that downregulation of miR-497-3p in TC tissues was induced by DNA methyltransferase-mediated hypermethylation. By performing dual-luciferase reporter assay, we identified that miR-497-3p targeted PAK1 while PAK1 could inhibit β-catenin expression. Through this mechanism, miR-497-3p exerted the anti-proliferative, anti-invasive, pro-apoptotic, and anti-tumorigenic effects on TC cells on the strength of the results from gain-of-function and rescue experiments. This study suggested that hypermethylation of miR-497-3p resulted in upregulation of β-catenin dependent on PAK1 and contributed to cancer progression in TC, which highlighted one of miR-mediated tumorigenic mechanism.

CircNDST1 promotes papillary thyroid cancer progression via its interaction with CSNK2A1 to activate the PI3K-Akt pathway and epithelial-mesenchymal transition

BACKGROUND

Multiple studies have established a strong relationship between circRNA and cancer progression. Cervical lymph node metastasis is a key factor influencing the surgical approach and distant metastasis of papillary thyroid cancer (PTC). However, the role of circNDST1 in PTC has not been investigated. Our research focused on revealing the function and mechanism of action of circNDST1 in PTC.

METHODS

High-throughput sequencing and qPCR were used to assess the expression of circRNA in PTC tissues with extensive cervical lymph node metastasis and circNDST1 in cell lines, respectively. The proliferative effects of circNDST1 in vitro and in vivo were analyzed using CCK8, clone formation assay, EdU, and nude mouse tumorigenesis assay. The transwell scratch assay was employed in the scrutiny of the effect of circNDST1 on the migration and invasion abilities of thyroid cancer cells, while circNDST1's influence on the PI3K-Akt pathway and the Epithelial-Mesenchymal Transition (EMT) key protein expression was evaluated utilizing RNA sequencing and western blot. RNA pull-down and RIP were used to examine the binding of circNDST1 to CSNK2A1.

RESULTS

CircNDST1 was highly expressed in PTC cell lines, but knocking it down inhibited the proliferation, migration, and invasive abilities of TPC1 and KTC1 cell lines. CircNDST1 bonded with CSNK2A1 and promoted the interaction between CSNK2A1 and Akt, leading to the activation of the PI3K-Akt pathway and EMT.

CONCLUSION

CircNDST1's high expression boosted thyroid cancer progression through the activation of the PI3K-Akt pathway and EMT in a CSNK2A1-dependent manner.

Hyperactivation of p21-Activated Kinases in Human Cancer and Therapeutic Sensitivity

Over the last three decades, p21-activated kinases (PAKs) have emerged as prominent intracellular nodular signaling molecules in cancer cells with a spectrum of cancer-promoting functions ranging from cell survival to anchorage-independent growth to cellular invasiveness. As PAK family members are widely overexpressed and/or hyperactivated in a variety of human tumors, over the years PAKs have also emerged as therapeutic targets, resulting in the development of clinically relevant PAK inhibitors. Over the last two decades, this has been a promising area of active investigation for several academic and pharmaceutical groups. Similar to other kinases, blocking the activity of one PAK family member leads to compensatory activity on the part of other family members. Because PAKs are also activated by stress-causing anticancer drugs, PAKs are components in the rewiring of survival pathways in the action of several therapeutic agents; in turn, they contribute to the development of therapeutic resistance. This, in turn, creates an opportunity to co-target the PAKs to achieve a superior anticancer cellular effect. Here we discuss the role of PAKs and their effector pathways in the modulation of cellular susceptibility to cancer therapeutic agents and therapeutic resistance.

Development and Utility of a PAK1-Selective Degrader

Overexpression of PAK1, a druggable kinase, is common in several malignancies, and inhibition of PAK1 by small molecules has been shown to impede the growth and survival of such cells. Potent inhibitors of PAKs 1-3 have been described, but clinical development has been hindered by recent findings that PAK2 function is required for normal cardiovascular function in adult mice. A unique allosteric PAK1-selective inhibitor, NVS-PAK1-1, provides a potential path forward, but has modest potency. Here, we report the development of BJG-05-039, a PAK1-selective degrader consisting of NVS-PAK1-1 conjugated to lenalidomide, a recruiter of the E3 ubiquitin ligase substrate adaptor Cereblon. BJG-05-039 induced selective degradation of PAK1 and displayed enhanced anti-proliferative effects relative to its parent compound in PAK1-dependent, but not PAK2-dependent, cell lines. Our findings suggest that selective PAK1 degradation may confer more potent pharmacological effects compared with catalytic inhibition and highlight the potential advantages of PAK1-targeted degradation.

Non-genomic activation of the AKT-mTOR pathway by the mitochondrial stress response in thyroid cancer

Cancer progression is associated with metabolic reprogramming and causes significant intracellular stress; however, the mechanisms that link cellular stress and growth signalling are not fully understood. Here, we identified a mechanism that couples the mitochondrial stress response (MSR) with tumour progression. We demonstrated that the MSR is activated in a significant proportion of human thyroid cancers via the upregulation of heat shock protein D family members and the mitokine, growth differentiation factor 15. Our study also revealed that MSR triggered AKT/S6K signalling by activating mTORC2 via activating transcription factor 4/sestrin 2 activation whilst promoting leucine transporter and nutrient-induced mTORC1 activation. Importantly, we found that an increase in ^mtDNA played an essential role in MSR-induced mTOR activation and that crosstalk between MYC and MSR potentiated mTOR activation. Together, these findings suggest that the MSR could be a predictive marker for aggressive human thyroid cancer as well as a useful therapeutic target.

Roles of Cadherin2 in Thyroid Cancer

Background

The majority of drug-resistant cells in Thyroid cancer (THCA) tend to exhibit an Epithelial mesenchymal transition (EMT) phenotype, and abnormal expression of the cell adhesion molecule Cadherin2 (CDH2) is a hallmark of EMT. However, the roles of CDH2 in THCA and its underlying mechanisms are unknown.

Methods

We analyzed the CDH2 expression in The Cancer Genome Atlas (TCGA) database and screened for genes positively associated with CDH2. Small interfering RNA and cell transfection were used for knocking down CDH2 in THCA cells, cell counting kit-8 (CCK-8) assay and immunofluorescence to detect cell proliferation. Binding miRNAs of CDH2 and CDH2-associated genes were predicted using the Encyclopedia of RNA Interactomes (ENCORI) database. The expression of genes in clinical THCA tissues was investigated from the Human Protein Atlas (HPA) database and validated by qRT-PCR. We conducted the cell functions pathways of CDH2 and CDH2-associated gene FRMD3 by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. We also showed the correlation between CDH2 and FRMD3 expression and tumor immune infiltration.

Results

The expression of CDH2 was significantly higher in THCA tumor tissues compared to normal tissues. Moreover, there were strongly associations of CDH2 expression with the stages T and N. Cellular function assays showed that CDH2 exerted its growth-promoting activity of THCA. To better understand how CDH2 was regulated in THCA, we sought genes associated with CDH2. Correlation analysis revealed that there were negative correlations between genes (CDH2, FRMD3) and miRNAs (hsa-miR-410-3p, hsa-miR-411-5p, hsa-miR-299-5p). Moreover, CDH2 and FRMD3 expression were significantly higher in tumor tissues than in normal tissues, while hsa-miR-410-3p, hsa-miR-411-5p and hsa-miR-299-5p were significantly decreased in tumor tissues compared with normal tissues in THCA. GO and KEEG results showed that CDH2 and FRMD3 were strongly associated with immune-related functions. High expression of CDH2 and FRMD3 was linked to the suppression of immune cells. There were strong negativity correlations between CDH2, FRMD3 and T-cell exhaustion factors.

Conclusion

Our data indicated that CDH2 and CDH2-related gene FRMD3 might have the critical effects on altering tumors becoming ‘cold tumors’ eventually leading to immune checkpoint inhibitor resistance.

Circular RNA hsa_circ_0004396 acts as a sponge of miR-615-5p to promote non-small cell lung cancer progression and radioresistance through the upregulation of P21-Activated Kinase 1

BACKGROUNDS

CircRNA hsa_circ_0004396 has been confirmed to be upregulated in human non-small cell lung cancer (NSCLC). The aim of his study was to evaluate its mechanism in the radioresistance and progression of NSCLC.

METHODS

Hsa_circ_0004396, miR-615-5p, and P21-Activated Kinase 1 (PAK1) were measured by reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR). The binding between miR-615-5p and hsa_circ_0004396 or PAK1 was predicted by circinteractome or Targetscan, as verified by dual-luciferase reporter assay and RIP assay. Proliferation, clonogenicity capacity, cell cycle progression, apoptosis, migration, and invasion were assessed by CCK-8, colony formation, flow cytometry, and Transwell assay. Bcl-2, Bcl-2 associated protein X (Bax), MMP-2, and PAK1 protein levels were detected using western blot assay. In addition, in vivo function of hsa_circ_0004396 was evaluated by tumor xenograft assay.

RESULTS

Hsa_circ_0004396 and PAK1 levels were upregulated, while miR-615-5p was declined in NSCLC. Hsa_circ_0004396 silencing inhibited NSCLC cell malignant behavior and induced radiosensitivity. Hsa_circ_0004396 functions as a molecular sponge of miR-615-5p to regulate PAK1 expression. Moreover, hsa_circ_0004396 knockdown inhibited NSCLC tumor growth in vivo.

CONCLUSION

Our findings demonstrated that hsa_circ_0004396 promoted NSCLC development and radioresistance through the miR-615-5p/PAK1 axis, which might provide a new therapeutic target for NSCLC treatment.

Long non-coding ROR promotes the progression of papillary thyroid carcinoma through regulation of the TESC/ALDH1A1/TUBB3/PTEN axis

Papillary thyroidal carcinoma (PTC) is a common endocrine cancer that plagues people across the world. The potential roles of long non-coding RNAs (lncRNAs) in PTC have gained increasing attention. In this study, we aimed to explore whether lncRNA ROR affects the progression of PTC, with the involvement of tescalcin (TESC)/aldehyde dehydrogenase isoform 1A1 (ALDH1A1)/βIII-tubulin (TUBB3)/tensin homolog (PTEN) axis. PTC tumor and adjacent tissues were obtained, followed by measurement of lncRNA ROR and TESC, ALDH1A1, and TUBB3 expression. Interactions among lncRNA ROR, TESC, ALDH1A1, TUBB3, and PTEN were evaluated by ChIP assay, RT-qPCR, or western blot analysis. After ectopic expression and depletion experiments in PTC cells, MTT and colony formation assay, Transwell assay, and flow cytometry were performed to detect cell viability and colony formation, cell migration and invasion, and apoptosis, respectively. In addition, xenograft in nude mice was performed to test the effects of lncRNA ROR and PTEN on tumor growth in PTC in vivo. LncRNA ROR, TESC, ALDH1A1, and TUBB3 were highly expressed in PTC tissues and cells. Overexpression of lncRNA ROR activated TESC by inhibiting the G9a recruitment on the promoter of TESC and histone H3-lysine 9me methylation. Moreover, TESC upregulated ALDH1A1 expression to increase TUBB3 expression, which then reduced PTEN expression. Overexpression of lncRNA ROR, TESC, ALDH1A1 or TUBB3 and silencing of PTEN promoted PTC cell viability, colony formation, migration, and invasion while suppressing apoptosis. Moreover, overexpression of lncRNA ROR increased tumor growth by inhibiting PTEN in vivo. Taken together, the current study demonstrated that lncRNA ROR mediated TESC/ALDH1A1/TUBB3/PTEN axis, thereby facilitating the development of PTC.

The Use of Nanomedicine to Target Signaling by the PAK Kinases for Disease Treatment

P21-activated kinases (PAKs) are serine/threonine kinases involved in the regulation of cell survival, proliferation, inhibition of apoptosis, and the regulation of cell morphology. Some members of the PAK family are highly expressed in several types of cancer, and they have also been implicated in several other medical disorders. They are thus considered to be good targets for treatment of cancer and other diseases. Although there are several inhibitors of the PAKs, the utility of some of these inhibitors is reduced for several reasons, including limited metabolic stability. One way to overcome this problem is the use of nanoparticles, which have the potential to increase drug delivery. The overall goals of this review are to describe the roles for PAK kinases in cell signaling and disease, and to describe how the use of nanomedicine is a promising new method for administering PAK inhibitors for the purpose of disease treatment and research. We discuss some of the basic mechanisms behind nanomedicine technology, and we then describe how these techniques are being used to package and deliver PAK inhibitors.

RAC1 Alterations Induce Acquired Dabrafenib Resistance in Association with Anaplastic Transformation in a Papillary Thyroid Cancer Patient

BRAF-activating mutations are the most frequent driver mutations in papillary thyroid cancer (PTC). Targeted inhibitors such as dabrafenib have been used in advanced BRAF-mutated PTC; however, acquired resistance to the drug is common and little is known about other effectors that may play integral roles in this resistance. In addition, the induction of PTC dedifferentiation into highly aggressive KRAS-driven anaplastic thyroid cancer (ATC) has been reported. We detected a novel RAC1 (P34R) mutation acquired during dabrafenib treatment in a progressive metastatic lesion with ATC phenotype. To identify a potential functional link between this novel mutation and tumor dedifferentiation, we developed a cell line derived from the metastatic lesion and compared its behavior to isogenic cell lines and primary tumor samples. Our data demonstrated that RAC1 mutations induce changes in cell morphology, reorganization of F-actin almost exclusively at the cell cortex, and changes in cell adhesion properties. We also established that RAC1 amplification, with or without mutation, is sufficient to drive cell proliferation and resistance to BRAF inhibition. Further, we identified polyploidy of chromosome 7, which harbors RAC1, in both the metastatic lesion and its derived cell line. Copy number amplification and overexpression of other genes located on this chromosome, such as TWIST1, EGFR, and MET were also detected, which might also lead to dabrafenib resistance. Our study suggests that polyploidy leading to increased expression of specific genes, particularly those located on chromosome 7, should be considered when analyzing aggressive thyroid tumor samples and in further treatments.

Fermitin family member 2 promotes melanoma progression by enhancing the binding of p-α-Pix to Rac1 to activate the MAPK pathway

We identified fermitin family member 2 (FERMT2, also known as kindlin-2) as a potential target in A375 cell line by siRNA library screening. Drugs that target mutant BRAF kinase lack durable efficacy in the treatment of melanoma because of acquired resistance, thus the identification of novel therapeutic targets is needed. Immunohistochemistry was used to identify kindlin-2 expression in melanoma samples. The interaction between kindlin-2 and Rac1 or p-Rac/Cdc42 guanine nucleotide exchange factor 6 (α-Pix) was investigated. Finally, the tumor suppressive role of kindlin-2 was validated in vitro and in vivo. Analysis of clinical samples and Oncomine data showed that higher levels of kindlin-2 predicted a more advanced T stage and M stage and facilitated metastasis and recurrence. Kindlin-2 knockdown significantly inhibited melanoma growth and migration, whereas kindlin-2 overexpression had the inverse effects. Further study showed that kindlin-2 could specifically bind to p-α-Pix(S13) and Rac1 to induce a switch from the inactive Rac1-GDP conformation to the active Rac1-GTP conformation and then stimulate the downstream MAPK pathway. Moreover, we revealed that a Rac1 inhibitor suppressed melanoma growth and metastasis and the combination of the Rac1 inhibitor and vemurafenib resulted in a better therapeutic outcome than monotherapy in melanoma with high kindlin-2 expression and BRAF mutation. Our results demonstrated that kindlin-2 promoted melanoma progression, which was attributed to specific binding to p-α-Pix(S13) and Rac1 to stimulate the downstream MAPK pathway. Thus, kindlin-2 could be a potential therapeutic target for treating melanoma.

New Horizons: Emerging Therapies and Targets in Thyroid Cancer

The treatment of patients with progressive metastatic follicular cell-derived and medullary thyroid cancers that do not respond to standard therapeutic modalities presents a therapeutic challenge. As a deeper understanding of the molecular drivers for these tumors has occurred and more potent and specific compounds are developed, the number of Food and Drug Administration (FDA)-approved treatments for thyroid cancer has expanded. In addition, with the advent of disease-agnostic target-directed FDA approvals an ever-broadening number of therapeutic options are available for clinicians and patients. However, to date, complete remissions are rare, the average durations of response are relatively modest, and toxicities are common. These factors accentuate the need for further understanding of the mechanisms of resistance that result in treatment failures, the development of biomarkers that can improve patient selection for treatment earlier in the disease process, and the continued need for new therapeutic strategies. In this article, recent approvals relevant to thyroid cancer will be discussed along with selected new potential avenues that might be exploited for future therapies.

AHNAK2 is a novel prognostic marker and correlates with immune infiltration in papillary thyroid cancer: Evidence from integrated analysis

Papillary thyroid cancer (PTC) is the most prevalent endocrine tumor, and its incidence is still increasing. The mechanisms of PTC dedifferentiation and malignant progression remain unclear. In this study, we identified AHNAK2 as a key gene in PTC by differential expression analysis among four GEO datasets and validated its overexpression profile by data from the Oncomine, TCGA, and HPA databases and IHC staining analysis. AHNAK2 upregulation significantly correlated with advanced grades, stages, and lymph node events. Survival analysis suggested that AHNAK2 overexpression was coupled with poor overall survival. The immune infiltration analysis by TIMER and CIBERSORT indicated that AHNAK2 expression tightly correlated with the infiltration of diverse immune cell types, especially T cell subtypes. In addition, AHNAK2 is correlated with the expression of other conventional key genes of TC, such as PIK3CA, MAPK1, CTNNB1, and SLC5A5. AHNAK2 may be a novel prognostic marker for PTC.

p21-Activated Kinases in Thyroid Cancer

The family of p21-activated kinases (PAKs) are oncogenic proteins that regulate critical cellular functions. PAKs play central signaling roles in the integrin/CDC42/Rho, ERK/MAPK, PI3K/AKT, NF-κB, and Wnt/β-catenin pathways, functioning both as kinases and scaffolds to regulate cell motility, mitosis and proliferation, cytoskeletal rearrangement, and other cellular activities. PAKs have been implicated in both the development and progression of a wide range of cancers, including breast cancer, pancreatic melanoma, thyroid cancer, and others. Here we will discuss the current knowledge on the structure and biological functions of both group I and group II PAKs, as well as the roles that PAKs play in oncogenesis and progression, with a focus on thyroid cancer and emerging data regarding BRAF/PAK signaling.

Targeting Rho GTPase Signaling Networks in Cancer

As key regulators of cytoskeletal dynamics, Rho GTPases coordinate a wide range of cellular processes, including cell polarity, cell migration, and cell cycle progression. The adoption of a pro-migratory phenotype enables cancer cells to invade the stroma surrounding the primary tumor and move toward and enter blood or lymphatic vessels. Targeting these early events could reduce the progression to metastatic disease, the leading cause of cancer-related deaths. Rho GTPases play a key role in the formation of dynamic actin-rich membrane protrusions and the turnover of cell-cell and cell-extracellular matrix adhesions required for efficient cancer cell invasion. Here, we discuss the roles of Rho GTPases in cancer, their validation as therapeutic targets and the challenges of developing clinically viable Rho GTPase inhibitors. We review other therapeutic targets in the wider Rho GTPase signaling network and focus on the four best characterized effector families: p21-activated kinases (PAKs), Rho-associated protein kinases (ROCKs), atypical protein kinase Cs (aPKCs), and myotonic dystrophy kinase-related Cdc42-binding kinases (MRCKs).

Targeting XPO1 and PAK4 in 8505C Anaplastic Thyroid Cancer Cells: Putative Implications for Overcoming Lenvatinib Therapy Resistance

Lenvatinib is a multitargeted tyrosine kinase inhibitor (TKI) that shows improved median progression-free survival (PFS) in patients with thyroid carcinomas. However, virtually all patients ultimately progress, indicating the need for a better understanding of the mechanisms of resistance. Here, we examined the molecular profile of anaplastic thyroid cancer cells (8505C) exposed to lenvatinib and found that long-term exposure to lenvatinib caused phenotypic changes. Consistent with change toward mesenchymal morphology, activation of pro-survival signaling, nuclear exporter protein exportin 1 (XPO1) and Rho GTPase effector p21 activated kinases (PAK) was also observed. RNA-seq analysis showed that prolonged lenvatinib treatment caused alterations in numerous cellular pathways and several oncogenes such as CEACAM (carcinoembryonic antigen-related cell adhesion molecule) and NUPR1 (Nuclear protein 1) were also upregulated. Further, we evaluated the impact of XPO1 and PAK4 inhibition in the presence or absence of lenvatinib. Targeted inhibition of XPO1 and PAK4 could sensitize the 8505C cells to lenvatinib. Both XPO1 and PAK4 inhibitors, when combined with lenvatinib, showed superior anti-tumor activity in 8505C sub-cutaneous xenograft. These studies bring forward novel drug combinations to complement lenvatinib for treating anaplastic thyroid cancer. Such combinations may possibly reduce the chances of lenvatinib resistance in thyroid cancer patients.

Expression of ANGPTL2 and its impact on papillary thyroid cancer

Background

Although the most thyroid carcinoma patients have good prognosis, around 20% of papillary thyroid carcinoma (PTC) patients have a high rate of metastasis and recurrence after routine treatment, which causes high lethality with these patients. Tumor proliferation, metastasis, and invasion are important predictors of PTC invasiveness and are key factors in cancer-related death. Angiopoietin-like 2 (ANGPTL2), a secreted protein which belongs to the angiopoietin (ANGPTL) family, was reported to be involved in the regulation of several different type of cancer cell proliferation and metastasis. However, whether ANGPTL2 plays a role in the progression of PTC, particularly in metastasis and recurrence of PTC, remains unclear. Hence, the purpose of this study was to evaluate the level of ANGPTL2 in PTC and normal thyroid, as well as para-cancerous tissue. Furthermore, the impact of ANGPTL2 on PTC cell proliferation, metastasis, recurrence and invasion was assessed to investigate the possibility whether ANGPTL2 may become a novel target for PTC therapy and cancer prognosis.

Materials and methods

The level of ANGPTL2 in PTC and para-cancerous tissue was assessed by immunohistochemistry. The biological effect of ANGPTL2 on thyroid cancer cell proliferation and metastasis was investigated by the Cell Counting Kit-8 (CCK8) assay, cell scratch test, and transwell assay. Correlations of ANGPTL2 expression levels with proliferation, migration, and metastasis of thyroid cancer were assessed with the TCGA data set and analyzed by gene set enrichment analysis. Receiver operating characteristic analysis was used to evaluate the utility of ANGPTL2 as a biomarker for prediction of thyroid cancer. Survival analysis was performed using the thyroid cancer database in K-M Plotter to detect correlations between survival time and ANGPTL2 levels.

Results

Current study revealed that: (1) ANGPTL2 was highly expressed in thyroid cancer in comparison with adjacent normal thyroid tissue; (2) ANGPTL2 expression was increased with thyroid tumor progression; (3) ANGPTL2 increased proliferation of thyroid cancer cells; (4) ANGPTL2 promoted migration and invasion of thyroid cancer cells; (5) high level of ANGPTL2 in thyroid cancer patients were significantly associated with a poor prognosis. The patients showed a higher metastasis and recurrence rate.

Conclusion

ANGPTL2 promoted and enhanced proliferation, metastasis, and invasion of thyroid cancer cells. ANGPTL2 may be considered as a potential biomarker for diagnosis and prognosis of thyroid cancer patients. Further evaluation needs to be done to analyze the possibility of taking ANGPTL2 as a prognostic marker and therapeutic target for papillary thyroid cancer.