The efficacy of HRAS and CDK4/6 inhibitors in anaplastic thyroid cancer cell lines

Anaplastic thyroid cancer: Genetic roles, targeted therapy, and immunotherapy

Anaplastic thyroid cancer (ATC) stands as the most formidable form of thyroid malignancy, presenting a persistent challenge in clinical management. Recent years have witnessed a gradual unveiling of the intricate genetic underpinnings governing ATC through next-generation sequencing. The emergence of this genetic landscape has paved the way for the exploration of targeted therapies and immunotherapies in clinical trials. Despite these strides, the precise mechanisms governing ATC pathogenesis and the identification of efficacious treatments demand further investigation. Our comprehensive review stems from an extensive literature search focusing on the genetic implications, notably the pivotal MAPK and PI3K-AKT-mTOR signaling pathways, along with targeted therapies and immunotherapies in ATC. Moreover, we screen and summarize the advances and challenges in the current diagnostic approaches for ATC, including the invasive tissue sampling represented by fine needle aspiration and core needle biopsy, immunohistochemistry, and 18F-fluorodeoxyglucose positron emission tomography/computed tomography. We also investigate enormous studies on the prognosis of ATC and outline independent prognostic factors for future clinical assessment and therapy for ATC. By synthesizing this literature, we aim to encapsulate the evolving landscape of ATC oncology, potentially shedding light on novel pathogenic mechanisms and avenues for therapeutic exploration.

The Revolution of Targeted Therapies in Thyroid Cancer Treatment: Present and Future Promising Anti-Cancer Drugs

Thyroid cancer prevalence has increased in the last few decades. Whereas the majority of well-differentiated histotypes have effective therapeutic options, the most advanced cases lacked successful treatment until recent years. Genomic alterations have emerged as targets for new anti-cancer drugs. This molecular knowledge is gradually being translated into sophisticated approaches for the stratification, management, and therapies of patients with thyroid carcinomas. The genomic characterisation of tumours in clinical assistance serves as a tool for enhancing the prognostic assessment of patients with thyroid cancer and predicting their responses to the agents. The MAPK pathway is the most predominantly activated molecular route in this cancer. Several drugs have been developed to inhibit this pathway at different levels. However, the acquired resistance that emerges is the main problem in their use. Other strategies targeting not only driver mutations but also those that confer aggressive behaviour on tumours can be potential targetable options. Due to the new therapies, patients with the most aggressive histotypes have improved survival rates. Adverse events, although manageable, have a high prevalence among the current therapies. Selective inhibitors, immunotherapies, and the combination of both will play a pivotal role in the treatment and the improvements in overall survival in thyroid cancer patients.

The Genomic, Transcriptomic, and Immunologic Landscape of HRAS Mutations in Solid Tumors

Tipifarnib is the only targeted therapy breakthrough for HRAS-mutant (HRASmt) recurrent or metastatic head and neck squamous cell carcinoma (HNSCC). The molecular profiles of HRASmt cancers are difficult to explore given the low frequency of HRASmt. This study aims to understand the molecular co-alterations, immune profiles, and clinical outcomes of 524 HRASmt solid tumors including urothelial carcinoma (UC), breast cancer (BC), non-small-cell lung cancer (NSCLC), melanoma, and HNSCC. HRASmt was most common in UC (3.0%), followed by HNSCC (2.82%), melanoma (1.05%), BC (0.45%), and NSCLC (0.44%). HRASmt was absent in Her2+ BC regardless of hormone receptor status. HRASmt was more frequently associated with squamous compared to non-squamous NSCLC (60% vs. 40% in HRASwt, p = 0.002). The tumor microenvironment (TME) of HRASmt demonstrated increased M1 macrophages in triple-negative BC (TNBC), HNSCC, squamous NSCLC, and UC; increased M2 macrophages in TNBC; and increased CD8+ T-cells in HNSCC (all p < 0.05). Finally, HRASmt was associated with shorter overall survival in HNSCC (HR: 1.564, CI: 1.16-2.11, p = 0.003) but not in the other cancer types examined. In conclusion, this study provides new insights into the unique molecular profiles of HRASmt tumors that may help to identify new targets and guide future clinical trial design.

Knowledge mapping of anaplastic thyroid cancer treatments: a bibliometric analysis (2000-2023)

Context

Anaplastic thyroid cancer (ATC) is a relatively rare and extensively malignant kind of thyroid carcinoma. The poor prognosis and high mortality rate of ATC can be attributed to its invasive features and undifferentiated phenotype. At present, there is a lack of efficacious therapeutic options. In light of the elevated fatality rate, it is vital to possess a comprehensive comprehension of the scientific terrain pertaining to ATC. To gather the perspectives of different researchers about the topic of ATC treatment, we did a bibliometric network analysis, which offers a comprehensive view of the scholarly literature.

Methodology

A systematic search was conducted on the WoSCC database to identify publications pertaining to ATC treatment between the years 2000 and 2023. In this bibliometric investigation, the tools VOSviewers, CiteSpace, and the R package "bibliometrix" were employed to investigate the general attributes, developmental framework, and academic frontiers of the subject matter.

Results

1223 publications in total, written by 6937 scholars from 53 areas and 1402 institutions and published in 358 scholarly journals, were analyzed. There has been a gradual increase in the quantity of publications pertaining to ATC treatment. The United States and China emerged as the most prominent nations. The University of Texas MD Anderson Cancer Center and Memorial Sloan Kettering Cancer Counseling Center are prominent research institutions in highly productive countries. The journal Thyroid holds a prominent position within its discipline, being widely recognized as both the most popular and highly co-cited publication. According to the available data, Maria Cabanillas has authored the highest number of published articles, while RC Smallridge has received the highest number of co-citations. It turned out that the prevailing keywords encompassed expression, therapy, apoptosis, survival, activation, proliferation, metastasis, and other related terms. Immunotherapy, targeted therapy, and prognostic factors are the emerging research hotspots and trends.

Conclusions

This paper presents a complete overview of research trends and advancements in the treatment of ATC using bibliometric analysis. The acquisition of information will offer vital insights for funding and potential creative strategies in researching the treatment of ATC, which indicates the research frontiers as well as prevalent directions in recent years.

Genomic alterations in thyroid cancer: biological and clinical insights

Tumours can arise from thyroid follicular cells if they acquire driver mutations that constitutively activate the MAPK signalling pathway. In addition, a limited set of additional mutations in key genes drive tumour progression towards more aggressive and less differentiated disease. Unprecedented insights into thyroid tumour biology have come from the breadth of thyroid tumour sequencing data from patients and the wide range of mutation-specific mechanisms identified in experimental models, in combination with the genomic simplicity of thyroid cancers. This knowledge is gradually being translated into refined strategies to stratify, manage and treat patients with thyroid cancer. This Review summarizes the biological underpinnings of the genetic alterations involved in thyroid cancer initiation and progression. We also provide a rationale for and discuss specific examples of how to implement genomic information to inform both recommended and investigational approaches to improve thyroid cancer prognosis, redifferentiation strategies and targeted therapies.

Extracellular vesicle-carried GTF2I from mesenchymal stem cells promotes the expression of tumor-suppressive FAT1 and inhibits stemness maintenance in thyroid carcinoma

Through bioinformatics predictions, we identified that GTF2I and FAT1 were downregulated in thyroid carcinoma (TC). Further, Pearson's correlation coefficient revealed a positive correlation between GTF2I expression and FAT1 expression. Therefore, we selected them for this present study, where the effects of bone marrow mesenchymal stem cell-derived EVs (BMSDs-EVs) enriched with GTF2I were evaluated on the epithelial-to-mesenchymal transition (EMT) and stemness maintenance in TC. The under-expression of GTF2I and FAT1 was validated in TC cell lines. Ectopically expressed GTF2I and FAT1 were found to augment malignant phenotypes of TC cells, EMT, and stemness maintenance. Mechanistic studies revealed that GTF2I bound to the promoter region of FAT1 and consequently upregulated its expression. MSC-EVs could shuttle GTF2I into TPC-1 cells, where GTF2I inhibited TC malignant phenotypes, EMT, and stemness maintenance by increasing the expression of FAT1 and facilitating the FAT1-mediated CDK4/FOXM1 downregulation. In vivo experiments confirmed that silencing of GTF2I accelerated tumor growth in nude mice. Taken together, our work suggests that GTF2I transferred by MSC-EVs confer antioncogenic effects through the FAT1/CDK4/FOXM1 axis and may be used as a promising biomarker for TC treatment.

CDK4 phosphorylation status and rational use for combining CDK4/6 and BRAF/MEK inhibition in advanced thyroid carcinomas

Background

CDK4/6 inhibitors (CDK4/6i) have been established as standard treatment against advanced Estrogen Receptor-positive breast cancers. These drugs are being tested against several cancers, including in combinations with other therapies. We identified the T172-phosphorylation of CDK4 as the step determining its activity, retinoblastoma protein (RB) inactivation, cell cycle commitment and sensitivity to CDK4/6i. Poorly differentiated (PDTC) and anaplastic (ATC) thyroid carcinomas, the latter considered one of the most lethal human malignancies, represent major clinical challenges. Several molecular evidence suggest that CDK4/6i could be considered for treating these advanced thyroid cancers.

Methods

We analyzed by two-dimensional gel electrophoresis the CDK4 modification profile and the presence of T172-phosphorylated CDK4 in a collection of 98 fresh-frozen tissues and in 21 cell lines. A sub-cohort of samples was characterized by RNA sequencing and immunohistochemistry. Sensitivity to CDK4/6i (palbociclib and abemaciclib) was assessed by BrdU incorporation/viability assays. Treatment of cell lines with CDK4/6i and combination with BRAF/MEK inhibitors (dabrafenib/trametinib) was comprehensively evaluated by western blot, characterization of immunoprecipitated CDK4 and CDK2 complexes and clonogenic assays.

Results

CDK4 phosphorylation was detected in all well-differentiated thyroid carcinomas (n=29), 19/20 PDTC, 16/23 ATC and 18/21 thyroid cancer cell lines, including 11 ATC-derived ones. Tumors and cell lines without phosphorylated CDK4 presented very high p16CDKN2A levels, which were associated with proliferative activity. Absence of CDK4 phosphorylation in cell lines was associated with CDK4/6i insensitivity. RB1 defects (the primary cause of intrinsic CDK4/6i resistance) were not found in 5/7 tumors without detectable phosphorylated CDK4. A previously developed 11-gene expression signature identified the likely unresponsive tumors, lacking CDK4 phosphorylation. In cell lines, palbociclib synergized with dabrafenib/trametinib by completely and permanently arresting proliferation. These combinations prevented resistance mechanisms induced by palbociclib, most notably Cyclin E1-CDK2 activation and a paradoxical stabilization of phosphorylated CDK4 complexes.

Conclusion

Our study supports further clinical evaluation of CDK4/6i and their combination with anti-BRAF/MEK therapies as a novel effective treatment against advanced thyroid tumors. Moreover, the complementary use of our 11 genes predictor with p16/KI67 evaluation could represent a prompt tool for recognizing the intrinsically CDK4/6i insensitive patients, who are potentially better candidates to immediate chemotherapy.

SPRY4 as a Potential Mediator of the Anti-Tumoral Role of Macrophages in Anaplastic Thyroid Cancer Cells

Anaplastic thyroid carcinoma (ATC) is the most lethal subtype of thyroid cancer, with high invasive and metastatic potential, not responding to conventional treatments. Its aggressiveness may be influenced by macrophages, which are abundant cells in the tumor microenvironment. To investigate the role of macrophages in ATC aggressiveness, indirect co-cultures were established between ATC cell lines and THP-1-derived macrophages. Macrophages significantly increased both the migration and invasion of T235 cells (p < 0.01; p < 0.01), contrasting with a decrease in C3948 (p < 0.001; p < 0.05), with mild effects in T238 migration (p < 0.01) and C643 invasion (p < 0.05). Flow cytometry showed upregulation of CD80 (pro-inflammatory, anti-tumoral) and downregulation of CD163 (anti-inflammatory, pro-tumoral) in macrophages from co-culture with T235 (p < 0.05) and C3948 (p < 0.05), respectively. Accordingly, we found an upregulation of secreted pro-inflammatory mediators (e.g., GM-CSF, IL-1α; p < 0.05) in C3948-macrophage co-cultures. Proteomic analysis showed the upregulation of SPRY4, an inhibitor of the MAPK pathway, in C3948 cells from co-culture. SPRY4 silencing promoted cancer cell invasion, reverting the reduced invasion of C3948 caused by macrophages. Our findings support that macrophages play a role in ATC cell aggressiveness. SPRY4 is a possible modulator of macrophage-ATC cell communication, with a tumor suppressor role relevant for therapeutic purposes.

Mechanistic Insights of Thyroid Cancer Progression

Differentiated thyroid cancers (DTCs) are primarily initiated by mutations that activate the MAPK signaling cascade, typically at BRAF or RAS oncoproteins. DTCs can evolve to more aggressive forms, specifically, poorly differentiated (PDTC) and anaplastic thyroid cancers (ATC), by acquiring additional genetic alterations which deregulate key pathways. In this review, we focused on bona fide mutations involved in thyroid cancer progression for which consistent mechanistic data exist. Here we summarized the relevant literature, spanning approximately 2 decades, highlighting genetic alterations that are unquestionably enriched in PDTC/ATC. We describe the relevant functional data obtained in multiple in vitro and in vivo thyroid cancer models employed to study genetic alterations in the following genes and functional groups: TP53, effectors of the PI3K/AKT pathway, TERT promoter, members of the SWI/SNF chromatin remodeling complex, NF2, and EIF1AX. In addition, we briefly discuss other genetic alterations that are selected in aggressive thyroid tumors but for which mechanistic data is still either limited or nonexistent. Overall, we argue for the importance conveyed by preclinical studies for the clinical translation of genomic knowledge of thyroid cancers.

The effects of Abemaciclib on cell cycle and apoptosis regulation in anaplastic thyroid cancer cells

BACKGROUND

Anaplastic thyroid cancer (ATC) is an aggressive subtype of thyroid cancer, accounting for 1 to 2% of all cases. Deregulations of cell cycle regulatory genes including cyclins, cyclin-dependent kinases (CDKs), and endogenous inhibitors of CDKs (CKIs) are hallmarks of cancer cells and hence, studies indicate the inhibition of CDK4/6 kinases and cell cycle progression as potent therapeutic strategies. In this study, we investigated the anti-tumor activity of Abemaciclib, a CDK4 and CDK6 inhibitor, in ATC cell lines.

METHODS AND RESULTS

The ATC cell lines C643 and SW1736 were selected to study the antiproliferative effects of Abemaciclib using a cell proliferation assay and crystal violet staining assay. Annexin V/PI staining and cell cycle analysis by flow cytometry were also performed to examine the effects on apoptosis induction and cell cycle arrest. Wound healing assay and zymography analysis examined the effects of the drug on invasive abilities of ATC cells and Western blot analyses were applied to further study the anti-tumor mechanism of Abemaciclib, in addition to combination treatment with alpelisib. Our data demonstrated that Abemaciclib significantly inhibited cell proliferation and increased cellular apoptosis and cell cycle arrest in ATC cell lines, while considerably reducing cell migration and colony formation. The mechanism seemed to involve the PI3K pathway.

CONCLUSION

Our preclinical data highlight CDK4/6 as interesting therapeutic targets in ATC and suggest CDK4/6-blockade therapies as promising strategies in this malignancy.

A case of osteoclastic variant of anaplastic thyroid carcinoma: Diagnostic and prognostic marker studies by cytology

Anaplastic thyroid carcinoma is an infrequent, but aggressive fatal subtype of thyroid cancer. The osteoclastic variant of anaplastic carcinoma is a rare subtype of anaplastic carcinoma with rare cases reported in the literature. Molecular targeted therapies have emerged for the anaplastic carcinoma, necessitating accurate pathologic diagnosis with additional ancillary testing for directing clinical management. We present here the cytological diagnosis of an anaplastic thyroid carcinoma-osteoclastic variant on fine-needle aspiration (FNA), with emphasis on the novelty of utilizing the least invasive procedure (aspiration cytology) for rendering pathological diagnosis as well as identifying potential prognostic markers for targeted immunotherapy.

Cancer stem cell-like cells-derived exosomal CDKN2B-AS1 stabilizes CDKN2B to promote the growth and metastasis of thyroid cancer via TGF-β1/Smad2/3 signaling

As CDKN2B-AS1 is demonstrated to exert promotive effects on thyroid cancer (TC), this research aims to investigate the role of cancer stem cell-like cells (CSCs)-derived exosomal CDKN2B-AS1 in TC and the underlying regulatory mechanism. Specifically, CDKN2B expression and the correlation of CDKN2B with CDKN2B-AS1 in TC were determined via bioinformatics analysis and further verified by qRT-PCR. After transfection or co-culture with CSCs-derived exosomes, viability, migration, and invasion of TPC-1 and SW579 cells were evaluated by CCK-8, wound healing, and transwell assays, respectively. The uptake of exosomes by TC cells was detected by PKH67 labeling. In vivo tumor formation and metastasis models were established. Tumor volume and weight were calculated. Metastasis loci in lung tissues were observed by hematoxylin-eosin staining. The expression levels of CDKN2B-AS1, CDKN2B, and epithelial-mesenchymal transition- and TGF-β1/Smad2/3 signaling-related factors were detected by qRT-PCR or Western blot. Concretely, CDKN2B and CDKN2B-AS1 were highly expressed in TC, and there was a positive correlation between the two. In addition, CDKN2B-AS1 promoted the translation and stability of CDKN2B. Furthermore, CDKN2B-AS1 was highly expressed in CSCs and CSCs-derived exosomes which could be absorbed by TC cells. CDKN2B silencing inhibited viability, migration, invasion, protein levels of CDKN2B, N-cadherin and Vimentin, and TGF-β1/Smad2/3 signaling, while promoting E-cadherin expression in TC cells. CSCs-derived exosomal CDKN2B-AS1 did oppositely and reversed the effects of CDKN2B silencing on TC cells. CDKN2B silencing impeded tumor growth and metastasis in TC mice, while TGF-β1 performed inversely and impaired the effects of CDKN2B silencing. Collectively, CSCs-derived exosomal CDKN2B-AS1 stabilizes CDKN2B to promote growth and metastasis of TC via TGF-β1/Smad2/3 signaling.

Cyclin-dependent kinases-based synthetic lethality: Evidence, concept, and strategy

Synthetic lethality is a proven effective antitumor strategy that has attracted great attention. Large-scale screening has revealed many synthetic lethal genetic phenotypes, and relevant small-molecule drugs have also been implemented in clinical practice. Increasing evidence suggests that CDKs, constituting a kinase family predominantly involved in cell cycle control, are synthetic lethal factors when combined with certain oncogenes, such as MYC, TP53, and RAS, which facilitate numerous antitumor treatment options based on CDK-related synthetic lethality. In this review, we focus on the synthetic lethal phenotype and mechanism related to CDKs and summarize the preclinical and clinical discoveries of CDK inhibitors to explore the prospect of CDK inhibitors as antitumor compounds for strategic synthesis lethality in the future.

The Genomic Landscape of Thyroid Cancer Tumourigenesis and Implications for Immunotherapy

Thyroid cancer is the most prevalent endocrine malignancy that comprises mostly indolent differentiated cancers (DTCs) and less frequently aggressive poorly differentiated (PDTC) or anaplastic cancers (ATCs) with high mortality. Utilisation of next-generation sequencing (NGS) and advanced sequencing data analysis can aid in understanding the multi-step progression model in the development of thyroid cancers and their metastatic potential at a molecular level, promoting a targeted approach to further research and development of targeted treatment options including immunotherapy, especially for the aggressive variants. Tumour initiation and progression in thyroid cancer occurs through constitutional activation of the mitogen-activated protein kinase (MAPK) pathway through mutations in BRAF, RAS, mutations in the phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K) pathway and/or receptor tyrosine kinase fusions/translocations, and other genetic aberrations acquired in a stepwise manner. This review provides a summary of the recent genetic aberrations implicated in the development and progression of thyroid cancer and implications for immunotherapy.

Targeting Non-Oncogene Addiction: Focus on Thyroid Cancer

Thyroid carcinoma (TC) is the most common malignancy of endocrine organs with an increasing incidence in industrialized countries. The majority of TC are characterized by a good prognosis, even though cases with aggressive forms not cured by standard therapies are also present. Moreover, target therapies have led to low rates of partial response and prompted the emergence of resistance, indicating that new therapies are needed. In this review, we summarize current literature about the non-oncogene addiction (NOA) concept, which indicates that cancer cells, at variance with normal cells, rely on the activity of genes, usually not mutated or aberrantly expressed, essential for coping with the transformed phenotype. We highlight the potential of non-oncogenes as a point of intervention for cancer therapy in general, and present evidence for new putative non-oncogenes that are essential for TC survival and that may constitute attractive new therapeutic targets.

Establishment and characterization of a new patient-derived anaplastic thyroid cancer cell line (C3948), obtained through fine-needle aspiration cytology

PURPOSE

Anaplastic thyroid cancer (ATC) is among the most aggressive and unresectable tumors, presenting a bad prognosis. A better comprehension of the functional and molecular mechanisms behind the aggressiveness of this cancer, as well as new biomarkers for aggressiveness, prognosis, and response to therapy are required. However, owing to their irresectability, ATC tissue is not always accessible. Here we describe the establishment and characterization of a new patient-derived cell line, obtained from an unresectable ATC through fine-needle aspiration cytology (FNAC).

METHODS

The morphology, expression of epithelial and thyroid markers, cytogenetic, mutational and gene expression profiles, doubling time, and drug-resistance profile of the new cell line, designated C3948, were investigated using several methodologies: immunostaining, karyotype analysis, comparative genomic hybridization (CGH), fluorescent in situ hybridization (FISH), next-generation sequencing (NGS), Sanger sequencing, gene expression microarrays, cell counting, and IC₅₀ determination.

RESULTS

Results indicate that C3948 cell line has a histological phenotype representative of original ATC cells and a completely aberrant karyotype with many chromosomal losses and gains; harbors mutated TP53, STK11, and DIS3L2 genes; presents a gene expression profile similar to C643 ATC commercial cell line, but with some unique alterations; has a doubling time similar to C643; and the IC₅₀ profile for paclitaxel, doxorubicin, and cisplatin is similar to C643, although higher for cisplatin.

CONCLUSIONS

These observations are consistent with a typical ATC cell profile, supporting C3948 cell line as a novel preclinical model, and FNAC as a useful approach to better study anaplastic thyroid cancer, including testing of new anticancer therapies.

A Systematic Review of Phase II Targeted Therapy Clinical Trials in Anaplastic Thyroid Cancer

Anaplastic thyroid carcinoma (ATC) is a rare, but devastating disease. Despite multimodal approaches combining surgery, chemotherapy and radiation therapy, ATC is associated with a dire prognosis, with a median overall survival of only three to ten months. Novel treatments are thus urgently needed. Recent efforts towards the characterization of the molecular landscape of ATC have led to the identification of pro-oncogenic targetable alterations, lending promise for novel targeted therapeutic approaches. This systematic review summarizes the results of phase II clinical trials of targeted therapy in ATC, providing an overview of efficacy and safety profiles. The majority of trials to date have consisted of small single-arm studies and have presented modest results. However, only a minority of trials have selected or stratified patients by molecular alterations. In the setting of BRAF V600E mutated ATC, dabrafenib/trametinib combination therapy and vemurafenib monotherapy have both demonstrated efficacy. Everolimus has furthermore shown promising results in patients with PI3K/mTOR/AKT pathway alterations. These studies underscore the importance of molecular profiling of tumors for appropriate patient selection and determination of genomic correlates of response. Clinical trials are underway testing additional targeted therapies as monotherapy, or as a part of multimodal treatment, and in combination with immunotherapy.

Activation of CXCL5-CXCR2 axis promotes proliferation and accelerates G1 to S phase transition of papillary thyroid carcinoma cells and activates JNK and p38 pathways

C-X-C motif chemokine ligand 5 (CXCL5) is initially identified to recruit neutrophils by interacting with its receptor, C-X-C motif chemokine receptor 2 (CXCR2). Our prior work demonstrated that the expression levels of CXCL5 and CXCR2 were higher in the papillary thyroid carcinoma (PTC) tumors than that in the non-tumors. This study was performed to further investigate how this axis regulates the growth of PTC cells. B-CPAP cells (BRAF^V600E) and TPC-1 cells (RET/PTC rearrangement) expressing CXCR-2 were used as in vitro cell models. Our results showed that the recombinant human CXCL5 (rhCXCL5) promoted the proliferation of PTC cells. rhCXCL5 accelerated the G1/S transition, upregulated the expression of a group of S (DNA synthesis) or M (mitosis)-promoting cyclins and cyclin-dependent kinases (CDKs), and downregulated CDK inhibitors in PTC cells. The CDS region of homo sapiens CXCL5 gene was inserted into an eukaryotic expression vector to mediate the overexpression of CXCL5 in PTC cells. The phosphorylation of c-Jun N-terminal kinases (JNK) and p38, and the nuclear translocation of c-Jun were enhanced by CXCL5 overexpression, whereas attenuated by CXCR2 antagonist SB225002. Additionally, CXCL5/CXCR2 axis, JNK and p38 pathway inhibitors, SB225002, SP600125 and SB203580, suppressed the growth of PTC cells overexpressing CXCL5 in nude mice, respectively. Collectively, our study demonstrates a growth-promoting effect of CXCL5-CXCR2 axis in PTC cells in vitro and in vivo.