Cetuximab chemotherapy resistance: Insight into the homeostatic evolution of head and neck cancer (Review)

The complex evolution of genetic alterations in cancer that occurs in vivo is a selective process involving numerous factors and mechanisms. Chemotherapeutic agents that prevent the growth and spread of cancer cells induce selective pressure, leading to rapid artificial selection of resistant subclones. This rapid evolution is possible because antineoplastic drugs promote alterations in tumor‑cell metabolism, thus creating a bottleneck event. The few resistant cells that survive in this new environment obtain differential reproductive success that enables them to pass down the newly selected resistant gene pool. The present review aims to summarize key findings of tumor evolution, epithelial‑mesenchymal transition and resistance to cetuximab therapy in head and neck squamous cell carcinoma.

Role of STAT3 in cancer cell epithelial‑mesenchymal transition (Review)

Since its discovery, the role of the transcription factor, signal transducer and activator of transcription 3 (STAT3), in both normal physiology and the pathology of numerous diseases, including cancer, has been extensively studied. STAT3 is aberrantly activated in different types of cancer, fulfilling a critical role in cancer progression. The biological process, epithelial‑mesenchymal transition (EMT), is indispensable for embryonic morphogenesis. During the development of cancer, EMT is hijacked to confer motility, tumor cell stemness, drug resistance and adaptation to changes in the microenvironment. The aim of the present review was to outline recent advances in knowledge of the role of STAT3 in EMT, which may contribute to the understanding of the function of STAT3 in EMT in various types of cancer. Delineating the underlying mechanisms associated with the STAT3‑EMT signaling axis may generate novel diagnostic and therapeutic options for cancer treatment.

Aberrant trophoblastic differentiation in human cancer: An emerging novel therapeutic target (Review)

Various types of human cancer may develop aberrant trophoblastic differentiation, including histological changes and altered expression of β‑human chorionic gonadotropin (β‑hCG). Aberrant trophoblastic differentiation in epithelial cancer is usually associated with poor differentiation, tumor metastasis, unfavorable prognosis and treatment resistance. Since β‑hCG‑targeting vaccines have failed in an early phase II trial, it is crucial to obtain a better understanding of the molecular pathogenesis of trophoblastic differentiation in human cancer. The present review summarizes the clinical and translational research on this topic with the aim of accelerating the development of an effective targeted therapy. Ectopic expression of β‑hCG promotes proliferation, migration, invasion, vasculogenesis and epithelial‑mesenchymal transition (EMT) in vitro, and enhances metastatic and tumorigenic capabilities in vivo. Signaling cascades modulated by β‑hCG include the TGF‑β receptor pathway, EMT‑related pathways, the c‑MET receptor tyrosine kinase and mitogen‑activated protein kinase/ERK pathways, and the SMAD2/4 pathway. Taken together, these findings indicated that TGF‑β receptors, c‑MET and ERK1/2 are potential therapeutic targets. Nevertheless, further investigation on the molecular basis of aberrant trophoblastic differentiation is mandatory to improve the design of precision therapy for this aggressive type of human cancer.

[Retracted] Upregulation of miR‑183‑5p is responsible for the promotion of apoptosis and inhibition of the epithelial‑mesenchymal transition, proliferation, invasion and migration of human endometrial cancer cells by downregulating Ezrin

Following the publication of this article, a concerned reader drew to the Editor's attention that, in Fig. 9C on p. 2478 showing the results of Transwell invasion assay experiments, unexpected areas of similarity were identified in terms of the cellular patterns revealed both within the data panels for the six different experiments portrayed in this figure, and comparing among them. After having conducted an internal investigation, the Editor of International Journal of Molecular Medicine has reached the conclusion that the overlapping sections of data shown in this figure were unlikely to have arisen by coincidence. Therefore, on the grounds of a lack of confidence in the integrity of these data, the Editor has decided that the article should be retracted from the publication. The authors were asked for an explanation to account for these concerns, but the Editorial Office did not receive a reply. The Editor apologizes to the readership for any inconvenience caused, and thanks the interested reader for drawing this matter to our attention. [International Journal of Molecular Medicine 42: 2469‑2480, 2018; DOI: 10.3892/ijmm.2018.3853].

[Retracted] Rotenone restrains colon cancer cell viability, motility and epithelial‑mesenchymal transition and tumorigenesis in nude mice via the PI3K/AKT pathway

Following the publication of this paper, it was drawn to the Editor's attention by a concerned reader that the immunofluorescence staining data shown in Fig. 3C, and the migration and invasion assay data shown in Figs. 4C and 4D were strikingly similar to data appearing in different form in other research articles written by different authors at different research institutes that had either already been published, or were submitted for publication at around the same time, one of which has been retracted. In addition, the western blotting data shown for the E‑cadherin and AKT protein bands in Fig. 5 were strikingly similar, albeit the bands had been flipped vertically. Owing to the fact that contentious data in the above article had already been submitted for publication elsewhere prior to its submission to International Journal of Molecular Medicine, the Editor has decided that this paper should be retracted from the Journal. The authors were asked for an explanation to account for these concerns, but the Editorial Office did not receive a reply. The Editor apologizes to the readership for any inconvenience caused. [International Journal of Molecular Medicine 44: 700‑708, 2020; DOI: 10.3892/ijmm.2020.4637].

Upregulated enhancer of rudimentary homolog promotes epithelial‑mesenchymal transition and cancer cell migration in lung adenocarcinoma

Lung adenocarcinoma (LUAD) is one of the deadliest cancers regarding both mortality rate and number of deaths and warrants greater effort in the development of potential therapeutic targets. The enhancer of rudimentary homolog (ERH) has been implicated in the promotion and progression of certain types of cancer. In the present study, ERH was assessed for its expression pattern and survival association with LUAD in public transcriptomic and proteomic databases. Bioinformatic methods and data from websites, including University of Alabama at Birmingham CANcer data analysis Portal and The Cancer Genome Atlas, were utilized to demonstrate the functional behaviors and corresponding pathways of ERH in LUAD. Human A549 and CL1‑0 cell lines were used to validate the findings via functional assays. It was demonstrated that the expression of ERH, at both the transcriptomic and proteomic levels, was higher in LUAD compared with in adjacent non‑tumor lung tissue and was associated with worse survival prognosis. Moreover, high ERH expression was correlated with more aggressive functional states, such as cell cycle and invasion in LUAD, and the positive ERH‑correlated gene set was associated with worse survival and an immunosuppressive tumor microenvironment. Small nuclear ribonucleoprotein polypeptide G was identified as a molecule that potentially interacted with ERH. Lastly, it was demonstrated that ERH promoted epithelial‑mesenchymal transition and cell migration in vitro, but not proliferation. In conclusion, higher expression of ERH in LUAD may facilitate cancer progression and confer worse outcomes. Further deep investigation into the role of ERH in LUAD is needed.

[Corrigendum] Roles of the H19/microRNA‑675 axis in the proliferation and epithelial‑mesenchymal transition of human cutaneous squamous cell carcinoma cells

Following the publication of the above paper, a concerned reader drew to the authors' attention that, in Fig. 4C on p. 8, the 'Invasion, miR‑675‑inhibitor' data panel appeared to contain an overlapping section with the 'Invasion, mi‑R675‑inhibitor + pcDNA3.1‑H19' data panel for the SCL1 cell line, such that the data were likely to have been derived from the same original source, even though they were intended to show the results from differently performed experiments. After having examined the original data, the authors also realized that the 'Inhibitor‑NC' and 'miR‑675‑inhibitor' data panels showing the migration assay experiments for the A431 cell line in the same figure part had also inadvertently been derived from the same original source. After having been granted permission from the Editor of Oncology Reports to repeat the experiments shown in Fig. 4C, the revised version of Fig. 4, incorporating the new data for Fig. 4C, is shown on the next page. Note that these errors did not affect the overall conclusions reported in the study, and the repeated experiment yielded similar results to those obtained originally. The authors are grateful to the Editor for allowing them the opportunity to publish this corrigendum, and all the authors agree with the publication of this; furthermore, they apologize for any inconvenience caused to the readership of the Journal. [Oncology Reports 45: 39, 2021; DOI: 10.3892/or.2021.7990].

miR‑151a‑5p promotes the proliferation and metastasis of colorectal carcinoma cells by targeting AGMAT

Colorectal carcinoma (CRC) is one of the most common types of digestive cancer. It has been reported that the ectopic expression of microRNAs (miRs) plays a critical role in the occurrence and progression of CRC. In addition, it has also been suggested that miR‑151a‑5p may serve as a useful biomarker for the early detection and treatment of different types of cancer and particularly CRC. However, the specific effects and underlying mechanisms of miR‑151a‑5p in CRC remain elusive. The results of the current study demonstrated that miR‑151a‑5p was upregulated in CRC cell lines and clinical tissues derived from patients with CRC. Functionally, the results showed that miR‑151a‑5p significantly promoted CRC cell proliferation, migration and invasion. Additionally, dual luciferase reporter assays verified that agmatinase (AGMAT) was a direct target of miR‑151a‑5p and it was positively associated with miR‑151a‑5p expression. Mechanistically, miR‑151a‑5p could enhance the epithelial‑mesenchymal transition of CRC cells. Taken together, the results of the current study revealed a novel molecular mechanism indicating that the miR‑151a‑5p/AGMAT axis could serve a crucial role in the regulation of CRC and could therefore be considered as a potential therapeutic strategy for CRC.

13‑cis‑retinoic acid inhibits the self‑renewal, migration, invasion and adhesion of cholangiocarcinoma cells

13‑cis‑retinoic acid (13CRA), a Food and Drug Administration‑approved drug for severe acne, is currently being investigated for its potential use in skin cancer prevention. 13CRA has been reported to exhibit antitumor effects against various types of cancer cells, both in vitro and in vivo. However, to the best of our knowledge, no information is yet available regarding the effects of 13CRA on cholangiocarcinoma (CCA), a malignancy of the bile duct epithelia. Currently, there are no reliably effective therapeutic options for metastatic CCA. The present study thus aimed to evaluate the effects of 13CRA on the self‑renewal, migration, invasion and adhesion of CCA cells, and also investigated the underlying mechanisms. The results revealed that 13CRA suppressed cell proliferation via the inhibition of the self‑renewal ability of CCA cells. 13CRA induced cell cycle arrest at the G₂/M phase in KKU‑100 and KKU‑213B CCA cells through the regulation of cell cycle‑regulatory genes and proteins. 13CRA reduced the cell migratory ability of both cell lines via the modulation of the genes and proteins associated with epithelial‑mesenchymal transition. 13CRA also inhibited the invasive and adhesive abilities of CCA cells via the suppression of genes and proteins associated with the invasion and adhesion of CCA cells. On the whole, these results suggested that 13CRA exerts suppressive effects on CCA cell proliferation, migration, adhesion and invasion.

Role of SUMOylation of STAT1 in tubular epithelial‑mesenchymal transition induced by high glucose

Tubulointerstitial fibrosis (TIF) is an important pathological change that occurs during the development of diabetic kidney disease. The epithelial‑mesenchymal transition (EMT) of renal tubular epithelial cells is a manifestation of TIF. STAT1, a member of the STAT family of transcription factors, can be modified by the small ubiquitin‑related modifier (SUMO), thus affecting the activity of STAT1. The present study investigated the role of STAT1 SUMOylation in high glucose‑induced tubular EMT by western blotting, immunocytochemistry, immunofluorescence, co‑immunoprecipitation and dual luciferase reporter analysis. The results indicated that in the process of high glucose‑induced EMT, STAT1 activation protected the cells from EMT. However, high glucose also increased the SUMOylation of STAT1, which prevented STAT1 from exerting an effective protective role by inhibiting its activity.

ENO2 affects the EMT process of renal cell carcinoma and participates in the regulation of the immune microenvironment

Clear cell renal cell carcinoma (ccRCC) is a frequent malignant tumor of the kidney which has a dismal prognosis. At present, targeted therapies and immunotherapy have achieved significant results; however, the overall survival rate of patients with ccRCC remains unacceptably poor. It is therefore necessary to find novel therapeutic and diagnostic targets for ccRCC. It has been reported that enolase 2 (ENO2) is an oncogene, although its function in the immune microenvironment and in the growth of ccRCC has yet to be fully elucidated. The present study analyzed the data of patients with ccRCC both from the Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) databases, and from clinical samples obtained from Third Affiliated Hospital of the Second Military Medical University to investigate the role of ENO2 in the progression of ccRCC and the correlation between ENO2 and certain clinical features. It was found that the expression of ENO2 was elevated both in patients with ccRCC retrieved from the GEO and TCGA databases and in clinical ccRCC samples obtained from Third Affiliated Hospital of the Second Military Medical University. In addition, the prognosis of patients was poorer when ENO2 was highly expressed. Gene Ontology (GO) analysis and Gene Set Enrichment Analysis (GSEA) confirmed that ENO2 participated in the regulation of various pathways in ccRCC. In vitro experiments including Cell Counting Kit‑8 cell proliferation assay, Transwell and Matrigel assays confirmed that ENO2 could promote the proliferation and migration of ccRCC cells. Furthermore, a number of immunosuppressive indicators were identified that positively correlated with ENO2 expression. In conclusion, the present study revealed that ENO2 expression promotes the proliferation, invasion and migration of ccRCC cells, and may serve as a novel predictor to evaluate prognosis and the efficacy of immune checkpoint blockade treatment for patients with ccRCC.

High expression of Sam68 contributes to metastasis by regulating vimentin expression and a motile phenotype in oral squamous cell carcinoma

The present study aimed to investigate the clinical and biological significance of Src-associated in mitosis 68 kDa (Sam68) in oral squamous cell carcinoma (OSCC). Immunohistochemical analysis was performed on tissue samples obtained from 77 patients with OSCC. Univariate analysis revealed that the high expression of Sam68 was significantly correlated with advanced pathological T stage (P=0.01), positive lymphovascular invasion (P=0.01), and pathological cervical lymph node metastasis (P<0.01). Moreover, multivariate analysis demonstrated that the high expression of Sam68 was an independent predictive factor for cervical lymph node metastasis (odds ratio, 4.39; 95% confidence interval, 1.49-14.23; P<0.01). These results indicated that high Sam68 expression contributed to tumor progression, especially cervical lymph node metastasis, in OSCC. mRNA sequencing was also performed to assess the changes in the transcriptome between OSCC cells with Sam68 knockdown and control cells with the aim of elucidating the biological roles of Sam68. Gene Ontology enrichment analysis revealed that downregulated differentially expressed genes (DEGs) were concentrated in some biological processes related to epithelial-mesenchymal transition. Among these DEGs, it was established that vimentin was particularly downregulated in these cells. It was also confirmed that Sam68 knockdown reduced the motility of OSCC cells. Furthermore, the immunohistochemical study of vimentin identified the association between vimentin expression and Sam68 expression as well as cervical lymph node metastasis. In conclusion, the present study suggested that the high expression of Sam68 may contribute to metastasis by regulating vimentin expression and a motile mesenchymal phenotype in OSCC.

UBE2T regulates FANCI monoubiquitination to promote NSCLC progression by activating EMT

Fanconi anemia complementation group I (FANCI) is a critical protein for maintaining DNA stability. However, the exact role of FANCI in tumors remains to be elucidated. The present study aimed to explore the role and potential mechanism of action of FANCI in non-small cell lung cancer (NSCLC). To quantify the expression levels of FANCI and ubiquitin-conjugating enzyme E2T (UBE2T) in NSCLC tissues, reverse-transcription quantitative PCR and western blotting were employed. Cell Counting Kit-8, wound healing and Transwell assays along with flow cytometry analysis and tumor xenograft were used to investigate the biological effects of FANCI in NSCLC in vitro and in vivo. The binding of FANCI with UBE2T was confirmed using a co-immunoprecipitation assay. Epithelial-to-mesenchymal transition (EMT) protein markers were quantified via western blotting. The results showed that FANCI expression level was higher in NSCLC tumor tissues, compared with adjacent tissues. In A549 and H1299 cells, knockdown of FANCI inhibited cell proliferation, migration, invasion, cell cycle and EMT in vitro. Tumor growth was repressed in vitro, upon downregulation of FANCI expression. UBE2T was observed to directly bind to FANCI and regulate its monoubiquitination. Overexpression of UBE2T reversed the effects induced by FANCI knockdown in NSCLC cells. Furthermore, it was noted that FANCI interacted with WD repeat domain 48 (WDR48). Overexpression of WDR48 reversed the effects of FANCI on cell proliferation, migration and EMT. In conclusion, FANCI was identified to be a putative oncogene in NSCLC, wherein FANCI was monouniubiquitinated by UBE2T to regulate cell growth, migration and EMT through WDR48. The findings suggested that FANCI could be used as a prognostic biomarker and therapeutic target for NSCLC.

Overexpression of ERCC6L correlates with poor prognosis and confers malignant phenotypes of lung adenocarcinoma

Excision repair cross‑complementation group 6 like (ERCC6L) has been reported to be upregulated in a variety of malignant tumors and plays a critical oncogenic role. However, the role and molecular mechanism of ERCC6L in lung adenocarcinoma (LUAD) remain unclear, and were therefore investigated in the present study. Clinical data of patients with LUAD were obtained and bioinformatics analysis was performed to investigate the expression characteristics, prognostic value, and biological function of ERCC6L. In addition, cell function experiments were performed to detect the effect of ERCC6L silencing on the biological behavior of LUAD cells. The results revealed that ERCC6L expression was significantly higher in LUAD tissues vs. normal lung tissues and closely associated with nodal invasion, advanced clinical stage and survival in LUAD. Overexpression of ERCC6L was an independent prognostic biomarker of overall survival, progression‑free interval, and disease‑specific survival in patients with LUAD. DNA amplification and low methylation levels of ERCC6L suggested regulation at both the genetic and epigenetic levels. The most significant positive genes co‑expressed with ERCC6L were mainly enriched in the cell cycle signaling pathway. The major functions of ERCC6L in LUAD cells were positively correlated with the cell cycle, DNA damage, DNA repair, proliferation, invasion and epithelial‑mesenchymal transition (EMT). Knockdown of ERCC6L inhibited the proliferative, migratory and invasive abilities of A549 and PC9 cells. It also promoted cell apoptosis, and led to cell cycle arrest in the S phase. ERCC6L may regulate the EMT process through the Wnt/β‑catenin and Wnt/Notch 3 signaling pathways, thus regulating the tumorigenesis and progression of LUAD. The overexpression of ERCC6L may be a biological indicator for the diagnosis and prognosis of LUAD. ERCC6L may be a novel molecular target for the treatment of lung cancer.

Downregulation of microRNA‑423‑5p suppresses TGF‑β1‑induced EMT by targeting FOXP4 in airway fibrosis

Airway fibrosis (AF) is a common disease that can severely affect patient prognosis. Epithelial-mesenchymal transition (EMT) participates in the pathophysiological development of AF and several studies have demonstrated that some microRNAs (miRNAs) contribute to the development of EMT. The aim of this study was to investigate the function of miR-423-5p in the EMT process and its possible underlying mechanism in BEAS-2B cells. The present study utilized the BEAS-2B cell line to model EMT in AF. Online tools, fluorescence in situ hybridization analysis and an RNA pull-down assay were used to identify potential target genes of miR-423-5p. In addition, immunohistochemistry, wound healing assays, Transwell migration assays, flow cytometry, enzyme-linked immunosorbent assay, reverse transcription-quantitative PCR, western blot analysis and immunofluorescence staining were used to determine the function of miR-423-5p and its target gene in the EMT process in AF. The results indicated that the miR-423-5p expression in AF tissues and BEAS-2B cells stimulated with 10 ng/ml TGF-β1 for 24 h was significantly increased compared with that in the control group. Overexpression of miR-423-5p facilitated TGF-β1-induced EMT in BEAS-2B cells; by contrast, downregulation of miR-423-5p suppressed TGF-β1-induced EMT in BEAS-2B cells. Furthermore, forkhead box p4 (FOXP4) was identified as a potential target gene of miR-423-5p and changes in the miR-423-5p and FOXP4 expression were shown to significantly affect the expression of PI3K/AKT/mTOR pathway members. In summary, overexpression of miR-423-5P promoted the EMT process in AF by downregulating FOXP4 expression and the underlying mechanism may partly involve activation of the PI3K/AKT/mTOR pathway.

EGFR inhibition reverses epithelial‑mesenchymal transition, and decreases tamoxifen resistance via Snail and Twist downregulation in breast cancer cells

Tamoxifen resistance remains a major obstacle in the treatment of estrogen receptor (ER)‑positive breast cancer. In recent years, the crucial role of the epithelial‑mesenchymal transition (EMT) process in the development of drug resistance in breast cancer has been underlined. However, the central molecules inducing the EMT process during the development of tamoxifen resistance remain to be elucidated. In the present study, it was demonstrated that tamoxifen‑resistant breast cancer cells underwent EMT and exhibited an enhanced cell motility and invasive behavior. The inhibition of snail family transcriptional repressor 1 (Snail) and twist family BHLH transcription factor 1 (Twist) reversed the EMT phenotype and decreased the tamoxifen resistance, migration and invasion of tamoxifen‑resistant breast cancer cells. In addition, it was observed that the inhibition of epidermal growth factor receptor (EGFR) reversed the EMT phenotype in tamoxifen‑resistant MCF7 (MCF‑7/TR) cells via the downregulation of Snail and Twist. Notably, the EGFR inhibitor, gefitinib, decreased tamoxifen resistance, migration and invasion through the inhibition of Snail and Twist. On the whole, the results of the present study suggest that EGFR may be a promising therapeutic target for tamoxifen‑resistant breast cancer. Moreover, it was suggested that gefitinib may serve as a potent novel therapeutic strategy for breast cancer patients, who have developed tamoxifen resistance.

Copy number alterations and epithelial‑mesenchymal transition genes in diffuse and intestinal gastric cancers in Mexican patients

Gastric cancer (GC) is a common malignancy with the highest mortality rate among diseases of the digestive system, worldwide. The present study of GC alterations is crucial to the understanding of tumor biology and the establishment of important aspects of cancer prognosis and treatment response. In the present study, DNA from Mexican patients with diffuse GC (DGC), intestinal GC (IGC) or non‑atrophic gastritis (NAG; control) was purified and whole‑genome analysis was performed with high‑density arrays. Shared and unique copy number alterations (CNA) were identified between the different tissues involving key genes and signaling pathways associated with cancer. This led to the molecular distinction and identification of the most relevant molecular functions to be identified. A more detailed bioinformatics analysis of epithelial‑mesenchymal transition (EMT) genes revealed that the altered network associated with chromosomal alterations included 11 genes that were shared between DGC, IGC and NAG, as well as 19 DGC‑ and 7 IGC‑exclusive genes. Furthermore, the main molecular functions included adhesion, angiogenesis, migration, metastasis, morphogenesis, proliferation and survival. The present study provided the first whole‑genome high‑density array analysis in Mexican patients with GC and revealed shared and exclusive CNA‑associated genes in DGC and IGC. In addition, a bioinformatics‑predicted network was generated, focusing on CNA‑altered genes associated with EMT and the hallmarks of cancer, as well as precancerous alterations that may lead to GC. Molecular signatures of diffuse and intestinal GC, predicted bioinformatically, involve common and distinct CNA‑EMT genes related to the hallmarks of cancer that are potential candidates for screening biomarkers of GC, including early stages.

Methylation‑associated inactivation of JPH3 and its effect on prognosis and cell biological function in HCC

In recent years, researchers have found that epigenetics plays an important role in the occurrence and development of hepatocellular carcinoma (HCC). DNA methylation is involved in the proliferation and metastasis of HCC. However, the junctophilin 3 (JPH3) level and the potential regulatory mechanism of its DNA methylation in HCC remain uncertain. In the present study, 73 HCC samples were enrolled to analyze the expression of JPH3. Reverse‑transcription quantitative PCR, western blotting and immunohistochemistry were used to detect the expression of JPH3 in HCC. Kaplan‑Meier method and Cox regression analysis were applied to evaluate the prognostic impact of JPH3 on HCC patients. DNA methylation‑specific PCR and bisulfite Sanger sequencing were used to detect the degree of DNA methylation of JPH3 in HCC. The demethylation drug 5‑Aza‑2'‑deoxycytidine (5‑Aza) was used to reduce the DNA methylation of JPH3. The role of JPH3 in the malignant biological behavior of HCC by promoting epithelial‑mesenchymal transition (EMT) was confirmed by functional cell experiments. The results showed that JPH3 exhibited low levels in HCC tissues and cell lines. HCC patients with low expression of JPH3 had poor survival outcomes. JPH3 had higher DNA methylation levels in HCC tissues and cell lines. When the demethylation drug 5‑Aza was used to reduce the degree of methylation of JPH3, its protein expression level was significantly increased and it significantly inhibited the malignant biological behavior of HCC cells. Additionally, effective increase in the expression of JPH3 through gene regulation technology also inhibited the proliferation, invasion and migration of HCC cells. After altering the DNA methylation level of JPH3, the EMT of HCC cells was also affected. Therefore, our study demonstrated the inactivation of JPH3 by promoter methylation and its function as a tumor suppressor in HCC. JPH3 may serve as a biomarker for early diagnosis and as a potential therapeutic target for HCC.

RASSF10 exhibits tumor‑suppressing potential involving tumor proliferation, metastasis and epithelial‑mesenchymal transition in esophageal squamous cell carcinoma

Growing evidence indicates that Ras-association domain family 10 (RASSF10) is a novel tumor-suppressor gene that is involved in the inhibition of tumor progression and metastasis; however, the biological functions and molecular mechanisms of RASSF10 in esophageal squamous cell carcinoma (ESCC) have not yet been thoroughly elucidated. The expression of RASSF10 in ESCC tissues and adjacent non-tumor tissues was investigated employing quantitative polymerase chain reaction (qPCR) and immunohistochemistry (IHC) assays of tissue microarrays. The function of RASSF10 in ESCC cell growth, migration and invasion was determined by CCK-8, colony formation, scratch wound healing and Transwell invasion assays, respectively. The correlation between RASSF10 and markers related to epithelial-mesenchymal transition (EMT) was evaluated by tissue microarray (TMA)-IHC, western blotting and immunofluorescence staining. RASSF10 was found to be highly downregulated in ESCC tissues compared with that noted in the adjacent non-tumor tissues, and closely correlated with tumor progression and patient prognosis. Moreover, functional studies demonstrated that RASSF10 overexpression not only resulted in reduced cell growth and colony formation but also inhibited migration and invasion of the ESCC cells. Tumor RASSF10 expression was positively correlated with E-cadherin expression and negatively correlated with vimentin. In addition, it was demonstrated that the antineoplastic functions of RASSF10 mediate inactivation of the Wnt/β-catenin pathway in ESCC. Our findings revealed that RASSF10 may constitute a prognostic factor for ESCC patients and a crucial candidate for targeted therapy against ESCC.

[Corrigendum] lncRNA‑CASC15 promotes osteosarcoma proliferation and metastasis by regulating epithelial‑mesenchymal transition via the Wnt/β‑catenin signaling pathway

Following the publication of this article, the authors have re-examined their raw data and realized that the data of each group in Fig. 5B were inadvertently mixed up when the statistical analysis was performed, resulting in inconsistencies comparing between the presented results and the corrresponding results in Fig. 5A. Furthermore, the authors also realized that the expression levels of some of the genes had not been standardized. A corrected version of Fig. 5, showing more representative data for the vimentin and cyclin D blots in Fig. 5A and the corrected statistical analysis for Fig. 5B, is shown below. The authors sincerely apologize for the errors that went unnoticed before their paper was published, and thank the Editor for allowing them the opportunity to publish a Corrigendum. They also regret any inconvenience that these mistakes may have caused. [the original article was published on Oncology Reports 45: Article no. 76, 2021; DOI: 10.3892/or.2021.8027].

Atractylenolide III inhibits epithelial‑mesenchymal transition in small intestine epithelial cells by activating the AMPK signaling pathway

Compared with the available drugs for the treatment of fibrosis in other organs, the development of intestinal anti-fibrosis drugs is limited. Therefore, it is of practical significance to examine novel drugs to delay or block the development of intestinal fibrosis. The present study aimed to investigate the effect of atractylenolide III (ATL-III) on intestinal fibrosis. An MTT assay was used to detect the effect of ATL-III on the activity of IEC-6 cells. The migration and invasion of fibrotic cells stimulated with TGF-β were determined via wound healing and Transwell assays. An immunofluorescence assay and western blotting were conducted to assess the expression levels of protein associated with epithelial-mesenchymal transition (EMT). The role of the AMP-activated protein kinase (AMPK) pathway was verified using compound C (an AMPK inhibitor) treatment. The results of the present study indicated that ATL-III had no effect on the cells at a dose of 1–20 µmol/l. Moreover, ATL-III can inhibit the invasion and migration of cells induced by TGF-β1, as well as block the EMT process. It was found that ATL-III could also activate the AMPK pathway. Furthermore, compound C reduced the inhibitory effect of ATL-III on stimulated cells, which indicated that the AMPK pathway plays a role in the inhibition process. In conclusion, ATL-III may inhibit the EMT of IEC-6 cells stimulated with TGF-β1 by activating the AMPK signaling pathway.

Targeting MUCL1 protein inhibits cell proliferation and EMT by deregulating β‑catenin and increases irinotecan sensitivity in colorectal cancer

With >1.85 million cases and 850,000 deaths annually, colorectal cancer (CRC) is the third most common cancer detected globally. CRC is an aggressive malignancy with metastasis and, in spite of advances in improved treatment regimen, distant disease failure rates remain disappointingly high. Mucin-like 1 (MUCL1) is a small glycoprotein highly expressed mainly in breast cancer. The involvement of the MUCL1 protein in CRC progression and the underlying mechanism have been largely unknown. The aim of the present study was to investigate the MUCL1 expression profile and its functional significance in CRC. The Cancer Genome Atlas dataset revealed that MUCL1 expression was higher in colorectal tumor compared with normal tissues. MUCL1 was also revealed to be expressed in human CRC cell lines. The results demonstrated that MUCL1 promoted cell proliferation and colony formation, confirming its oncogenic potential. Silencing MUCL1 with short interfering RNA inhibited the protein expression of Bcl2 family proteins, such as Bcl2 and BclxL. Targeting MUCL1 resulted in significant inhibition in cell invasive and migratory behavior of HT-29 and SW620 cells. In addition, the expression of E-cadherin increased whereas the expression of vimentin decreased in MUCL1-silenced cells, confirming inhibition of epithelial-mesenchymal transition (EMT) process. Thus, it was revealed that MUCL1 plays a notable role in cell invasion and migration by inhibiting EMT in CRC. Mechanistically, MUCL1 drives β-catenin activation by Ser-552 phosphorylation, nuclear accumulation and transcriptional activation. Targeting MUCL1 increases the drug sensitivity of CRC cells towards irinotecan. These findings thus demonstrated that MUCL1 acts as a modifier of other pathways that play an important role in CRC progression and MUCL1 was identified as a potential target for CRC therapeutics.

Hypoxia induces radioresistance, epithelial‑mesenchymal transition, cancer stem cell‑like phenotype and changes in genes possessing multiple biological functions in head and neck squamous cell carcinoma

Hypoxia has been linked with increased resistance to treatment in various solid tumors, including head and neck squamous cell carcinoma (HNSCC). The aim of the present study was to identify genes involved in hypoxia‑mediated responses to radiotherapy in HNSCC. A total of three HNSCC cell lines with an epithelial phenotype were selected for this study and cultured under normoxic (21% O₂) or hypoxic (1% O₂) conditions. The sensitivity of the HNSCC cells to radiotherapy was assessed by a crystal violet assay. Western blotting (for protein expression), cDNA microarrays and reverse transcription‑quantitative PCR (for gene expression) were also applied. Small interfering RNA silencing was used to knock down target genes. The results revealed that hypoxia negatively affected the response of HNSCC cells to radiotherapy. Of note, increased levels of N‑cadherin, vimentin and fibronectin, as well as stem cell‑associated transcription factors, were observed under hypoxia. The microarray analysis revealed a number of hypoxia‑regulated genes that were involved in multiple biological functions. However, downregulation of hypoxia‑regulated genes did not affect sensitivity to radiotherapy of the investigated cell lines. Taken together, the present findings indicated several important pathways and genes that were involved in hypoxia and radiotherapy resistance. It is hypothesized that panels of reported hypoxia‑regulated genes may be useful for the prediction of radiotherapy responses in patients with HNSCC.

B7‑H3 promotes the epithelial‑mesenchymal transition of NSCLC by targeting SIRT1 through the PI3K/AKT pathway

Epithelial-mesenchymal transition (EMT) is a key step in cancer metastasis. B7-H3, a co-signaling molecule associated with poor prognosis of non-small cell lung cancer (NSCLC), promotes the metastasis of NSCLC by activating the EMT process. However, its underlying mechanism remains poorly understood. In the present study, it was shown that CRISPR/Cas9-mediated B7-H3 deletion downregulated the expression of the class III histone deacetylase, sirtuin-1 (SIRT1), in NSCLC A549 cells. Accordingly, SIRT1 silencing resulted in markedly decreased migration and invasion of A549 cells. Both B7-H3 gene-edited and SIRT1-silenced cells were typically characterized by an increased expression of the epithelial marker E-cadherin, and downregulation of the mesenchymal markers N-cadherin and vimentin, as compared with mock-edited and scrambled negative small interfering RNA control, respectively. It was further demonstrated that B7-H3 ablation significantly downregulated phosphorylated AKT/protein kinase B expression, and SIRT1 expression was substantially suppressed by the PI3K-specific inhibitor, LY294002. Taken together, the findings of the present study revealed that B7-H3-induced signaling upregulates SIRT1 expression via the PI3K/AKT pathway to promote EMT activation that is associated with metastasis in NSCLC.

Inhibition of GP130/STAT3 and EMT by combined bazedoxifene and paclitaxel treatment in ovarian cancer

The interleukin 6 (IL-6)/glycoprotein 130 (GP130)/signal transducer and activator of transcription 3 (STAT3) signalling pathway, with GP130 as an intermediate membrane receptor, is involved in the survival, metastasis, and resistance of ovarian cancer. Bazedoxifene, an FDA-approved drug, is an inhibitor of GP130 and a selective estrogen modulator (SERM). We studied the mechanism of the combination therapy of bazedoxifene and paclitaxel in inhibiting the IL-6-mediated GP130/STAT3 signaling pathway in ovarian cancer. Surface plasmon resonance (SPR) was used to assess the binding of bazedoxifene to GP130. Migration, invasion, and apoptosis of ovarian cancer cells were assessed using bazedoxifene and paclitaxel. In addition, we determined the effects of bazedoxifene and paclitaxel alone or in combination on the GP130/STAT3 pathway and epithelial-mesenchymal transition (EMT). The results revealed that the combination of bazedoxifene and paclitaxel suppressed cell viability, migration, and invasion in the ovarian cancer cells. In addition, the combination treatment increased apoptosis. Furthermore, bazedoxifene combined with paclitaxel inhibited the growth of ovarian cancer cells in a xenograft tumour model. This combination reduced STAT3 phosphorylation and suppressed gene expression and EMT. In conclusion, inhibition of GP130/STAT3 signalling and EMT via a combination of bazedoxifene and paclitaxel could be used as a therapeutic strategy by which to overcome ovarian cancer.

AIM2 inhibits the proliferation, invasion and migration, and promotes the apoptosis of osteosarcoma cells by inactivating the PI3K/AKT/mTOR signaling pathway

Osteosarcoma is a primary bone tumor that mainly occurs in children and adolescents. Absent in melanoma 2 (AIM2) has been demonstrated to be involved in regulating the occurrence and development of cancer, exerting oncogenic and pro-cancer effects; however, its role in osteosarcoma is poorly understood. The present study aimed to explore the function and molecular mechanism of AIM2 in the progression of osteosarcoma. In the present study, AIM2 expression was predicted using the Cancer Cell Line Encyclopedia database and examined in several osteosarcoma cell lines using reverse transcription-quantitative PCR and western blotting. Following AIM2 overexpression, cell proliferation and apoptosis were examined using Cell Counting Kit-8, colony formation and TUNEL staining assays. The expression levels of proteins related to apoptosis, epithelial-mesenchymal transition (EMT) and the PI3K/AKT/mTOR signaling pathway were determined by western blotting. Additionally, cell invasion and migration were assessed using Transwell and wound healing assays. After addition of the PI3K/AKT/mTOR signaling pathway inhibitor LY294002 or activator 740Y-P, cell function analysis was performed. The results demonstrated that AIM2 was expressed at low levels in osteosarcoma cell lines. AIM2 overexpression inhibited proliferation, invasion, migration and EMT, and promoted apoptosis in osteosarcoma cells. Furthermore, the levels of phosphorylated (p)-PI3K, p-AKT and p-mTOR were markedly downregulated following AIM2 overexpression. Furthermore, LY294002 treatment had the same effects as AIM2 upregulation on osteosarcoma cell proliferation, apoptosis, invasion, migration and EMT. By contrast, 740Y-P reversed the effects of AIM2 overexpression on the behavior of osteosarcoma cells. Overall, the findings of the present study demonstrated that AIM2 may inhibit the progression of osteosarcoma by inactivating the PI3K/AKT/mTOR signaling pathway, and suggested that AIM2 may be a promising marker for the treatment of osteosarcoma.

CMTM5 inhibits the development of prostate cancer via the EGFR/PI3K/AKT signaling pathway

Prostate cancer (PCa) endangers the life and health of older men. Most PCa cases develop into castration-resistant PCa (CRPC) within 2 years. At present, the molecular mechanisms of the occurrence and development of PCa and its transformation to CRPC remain unknown. The present study aimed to investigate the role of CKLF-like Marvel transmembrane domain containing family member 5 (CMTM5) in PCa and its molecular mechanism in vitro. PCa tissues and paired adjacent normal prostate tissues from 70 patients were collected to examine the expression levels of CMTM5 and EGFR via immunohistochemistry, reverse transcription-quantitative PCR and western blotting. Then, CMTM5-overexpressing DU145 cells were constructed, and CMTM5 expression in these transfected cells and vector control cells was examined via western blotting. Cell Counting Kit-8 and plate clone formation assays were used to evaluate the proliferation and colony number of CMTM5-overexpressing cells and vector control cells. Then, cell migration and invasion were assessed using wound healing assay, Transwell assay and immunofluorescence analysis with DAPI staining. The effect of CMTM5 on apoptosis and its underlying molecular mechanism were examined using western blotting and flow cytometry. The results demonstrated that CMTM5 expression in PCa tissues and cell lines was significantly downregulated, while EFGR expression was significantly upregulated. The proportion of high CMTM5 expression in PCa tissues was significantly lower compared with that in normal prostate tissues. By contrast, the proportion of high EGFR expression in PCa tissues was significantly increased compared with that in normal prostate tissues. Moreover, CMTM5 overexpression significantly inhibited cell proliferation, migration and invasion, and promoted cell apoptosis compared with vector control cells in vitro. Furthermore, the regulation of PCa by CMTM5 was associated with the downregulation of PI3K/AKT and its downstream Bcl-2 expression, as well as the upregulation of Bax expression. In conclusion, CMTM5 may be an effective tumor suppressor gene for PCa, especially for castration-resistant PCa, by downregulating EGFR and PI3K/AKT signaling pathway components.

Contrasting functions of the epithelial‑stromal interaction 1 gene, in human oral and lung squamous cell cancers

The epithelial‑stromal interaction 1 gene (EPSTI1) is known to play multiple roles in the malignant progression of breast cancer and also in some aspects of the immune responses to the tumor. However, the relevance of the gene in the onset/progression of oral squamous cell carcinoma (OSCC) and lung squamous cell carcinoma (LSCC) is not yet known. The present study was aimed at revealing the roles of EPSTI1 in conferring malignant characteristics to OSCC and LSCC, and the underlying mechanisms. Quantitative real‑time polymerase chain reaction (PCR) and western blot analyses demonstrated significant upregulation of EPSTI1 in all four OSCC cell lines (HSC2, HSC3, HSC3‑M3 and HSC4), and significant downregulation of EPST11 in all three LSCC cell lines (LK‑2, EBC‑1 and H226) used in the present study, as compared to the expression levels in the corresponding control cell lines. Both knockdown of EPST11 in OSCC and overexpression of the gene in LSCC suppressed cell proliferation, and induced cell‑cycle arrest in the G1 phase, with upregulation of p21 and downregulation of CDK2 and cyclin D1. Furthermore, these alterations of EPST11 gene expression in the OSCC and LSCC cell lines suppressed the cell migration ability and reversed the EMT phenotype of the tumor cells. Collectively, while EPSTI1 appears to have oncogenic roles in OSCC, it appears to exert tumor‑suppressive roles in LSCC. PCR array analyses revealed some genes whose expression levels were altered along with the modified EPSTI1 expression in both the OSCC and LSCC cell lines. These findings suggest that EPSTI1 may be a therapeutic target for both OSCC and LSCC.

FOXP4 promotes laryngeal squamous cell carcinoma progression through directly targeting LEF‑1

Forkhead box (FOX) proteins are multifaceted transcription factors that have been shown to be involved in cell cycle progression, proliferation and metastasis. FOXP4, a member of the FOX family, has been implicated in diverse biological processes in tumor initiation and progression. However, the molecular mechanisms of FOXP4 in laryngeal squamous cell carcinoma (LSCC) remain unknown. In the present study, differentially expressed transcripts in transforming growth factor‑β‑treated TU177 cells were screened using microarrays and it was found that FOXP4 was significantly upregulated. The high expression of FOXP4 was detected in LSCC tissues and cells, and predicted poor prognosis. The role of FOXP4 in laryngeal cancer cell proliferation, migration and invasion was determined by gain‑ and loss‑of‑function assays. Besides, FOXP4 was demonstrated to participate in the epithelial‑mesenchymal transition process at the mRNA and protein levels. Mechanically, FOXP4 directly bound to the promoter of lymphoid enhancer‑binding factor 1 and activated Wnt signaling pathway, which was confirmed via chromatin immunoprecipitation and luciferase reporter assays. Consequently, these findings provided novel mechanisms of FOXP4 in LSCC progression, which may be considered as potential therapeutic and prognostic targets for LSCC.

RHBDD1 promotes proliferation, migration, invasion and EMT in renal cell carcinoma via the EGFR/AKT signaling pathway

Renal cell carcinoma (RCC) is a common malignant tumor of the urinary system with a poor prognosis and high mortality rate. The increasing incidence of RCC poses a serious threat to human health. It is well-documented that rhomboid domain-containing protein 1 (RHBDD1) plays a vital role in cancer progression. The present study was designed to identify the biological functions of RHBDD1 in RCC and investigate the underlying regulatory mechanism, aiming to explore the novel molecular therapeutic targets for RCC. The protein and mRNA expression levels of RHBDD1 in normal renal tubule epithelium and human RCC cell lines were analyzed using western blotting and reverse transcription-quantitative PCR. Cell proliferation was determined using Cell Counting Kit-8 assays. Wound healing and Transwell assays were performed to determine cell migration and invasion, respectively. In addition, key proteins related to migration, invasion and epithelial-mesenchymal transition (EMT), such as matrix metalloproteinase (MMP)2, MMP9, MMP13, E-cadherin, N-cadherin, vimentin and Slug, were analyzed using western blotting. In addition, the EGFR/AKT signaling pathway was further studied using western blotting to determine the potential molecular mechanism. The results of the present study revealed that RHBDD1 expression levels were significantly upregulated in RCC cell lines. The knockdown of RHBDD1 inhibited cell proliferation, migration, invasion and EMT, while the overexpression of RHBDD1 promoted cell proliferation, migration, invasion and EMT in RCC. In addition, the knockdown of RHBDD1 suppressed the activation of the EGFR/AKT signaling pathway, while the overexpression of RHBDD1 activated the EGFR/AKT signaling pathway. Moreover, these stimulatory effects of RHBDD1 overexpression on RCC progression and the EGFR/AKT signaling pathway were partly reversed by gefitinib, an EGFR inhibitor. In conclusion, the findings of the present study suggested that RHBDD1 may be a crucial regulator of RCC by modulating the EGFR/AKT signaling pathway. The present study may provide a theoretical basis and potential targets for RCC treatment.

PPM1A as a key target of the application of Jiawei‑Maxing‑Shigan decoction for the attenuation of radiation‑induced epithelial‑mesenchymal transition in type II alveolar epithelial cells

Radiation‑induced lung tissue injury is an important reason for the limited application of radiotherapy on thoracic malignancies. Previously, we reported that administration of Jiawei‑Maxing‑Shigan decoction (JMSD) attenuated the radiation‑induced epithelial‑mesenchymal transition (EMT) in alveolar epithelial cells (AECs) via TGF‑β/Smad signaling. The present study aimed to examine the role of protein phosphatase Mg²⁺/Mn²⁺‑dependent 1A (PPM1A) in the anti‑EMT activity of JMSD on AECs. The components in the aqueous extract of JMSD were identified by high‑performance liquid chromatography coupled with electrospray mass spectrometry. Primary rat type II AECs were treated with radiation (60Co γ‑ray at 8 Gy) and JMSD‑medicated serum. PPM1A was overexpressed and knocked down in the AECs via lentivirus transduction and the effects of JMSD administration on the key proteins related to TGF‑β1/Smad signaling were measured by western blotting. It was found that radiation decreased the PPM1A expression in the AECs and JMSD‑medicated serum upregulated the PPM1A expressions in the radiation‑induced AECs. PPM1A overexpression increased the E‑cadherin level but decreased the phosphorylated (p‑)Smad2/3, vimentin and α‑smooth muscle actin (α‑SMA) levels in the AECs. By contrast, the PPM1A knockdown decreased the E‑cadherin level and increased the p‑Smad2/3, vimentin and α‑SMA levels in the AECs and these effects could be blocked by SB431542 (TGF‑β1/Smad signaling inhibitor). JMSD administration increased the E‑cadherin level and decreased the p‑Smad2/3, vimentin and α‑SMA levels in the AECs; however, these effects could be blocked by siPPM1A‑2. In conclusion, PPM1A is a key target of JMSD administration for the attenuation of the radiation‑induced EMT in primary type II AECs via the TGF‑β1/Smad pathway.

Silencing circ‑BIRC6 inhibits the proliferation, invasion, migration and epithelial‑mesenchymal transition of bladder cancer cells by targeting the miR‑495‑3p/XBP1 signaling axis

Circular RNAs (circRNAs) regulate gene expression by acting as a 'sponge' for microRNAs (miRs) and play crucial roles in tumorigenesis, including in bladder cancer (BC). circRNA‑baculoviral IAP repeat‑containing 6 (circ‑BIRC6) has been reported to participate in the pathogenesis of several cancer types. The present study aimed to elucidate the roles and potential mechanisms of circ‑BIRC6 in the progression of BC. circ‑BIRC6 expression levels in BC cell lines were determined using reverse transcription‑quantitative PCR. Following circ‑BIRC6 knockdown, cell proliferation, invasion and migration were detected using Cell Counting Kit‑8, colony formation, Transwell and wound healing assays, respectively. Western blotting was also conducted to evaluate the expression levels of X‑box binding protein 1 (XBP1) and epithelial‑mesenchymal transition (EMT)‑associated proteins. In addition, rescue experiments were performed using by transfecting a miR‑495‑3p inhibitor into T24 cells following circ‑BIRC6 knockdown. The interactions between circ‑BIRC6, miR‑495‑3p and XBP1 was verified using dual luciferase reporter assays. Moreover, T24 cells with circ‑BIRC6 knockdown and miR‑495‑3p inhibitor transfection were used for the tumor‑bearing experiment. Tumor growth was observed and Ki‑67 expression was determined using immunohistochemistry. The results demonstrated that circ‑BIRC6 expression was upregulated in BC cell lines. Moreover, circ‑BIRC6 knockdown notably attenuated the proliferation, invasion, migration and EMT of BC cells, which was blocked by the miR‑495‑3p inhibitor. It was also identified that circ‑BIRC6 sponged miR‑495‑3p to regulate XBP1 expression. In addition, results from the xenograft experiments indicated that the knockdown of circ‑BIRC6 and miR‑495‑3p expression significantly inhibited tumor growth. It was also found that the expression levels of XBP1, Ki‑67 and EMT‑associated proteins in tumor tissues of the co‑transfection group were markedly restored compared with the circ‑BIRC6 knockdown group. In conclusion, these findings demonstrated that circ‑BIRC6 knockdown suppressed BC tumorigenesis and progression via regulation of the miR‑495‑3p/XBP1 signaling axis, offering a promising therapeutic target for the treatment of BC.

PLAC1 is an independent predictor of poor survival, and promotes cell proliferation and invasion in cervical cancer

Placenta-specific protein 1 (PLAC1) is inversely associated with survival in several types of cancer. However, whether PLAC1 is involved in the progression of cervical cancer (CC) remains to be elucidated. Therefore, the present study aimed to evaluate the prognostic role of PLAC1 in CC by determining the relationship between clinicopathological factors, PLAC1 gene expression and survival prognosis using univariate and multivariate Cox proportional-hazards regression analyses. Similarly, Kaplan-Meier curves were evaluated with the log-rank test. Subsequently, gene set enrichment analysis was performed to compare the high- and low-PLAC1 expression phenotypes. Functional studies were further conducted in PLAC1-overexpressing HeLa cells and PLAC1-silenced MS751 cells, and western blotting was performed to determine whether PLAC1 promoted CC progression via epithelial-mesenchymal transition (EMT). The findings demonstrated that high expression of PLAC1 was associated with American Joint Committee on Cancer metastasis pathological score and suggested a poor overall survival. ‘mTOR complex 1 signaling’, ‘interferon α response’ and ‘hypoxia’ were differentially enriched in the high-PLAC1 phenotype. Furthermore, PLAC1 promoted the invasion of CC cells in vitro. E-cadherin expression was decreased in the PLAC1-overexpressing cells, accompanied by increased expression of the mesenchymal markers, Vimentin, MMP2 and Slug, and the opposite effects were observed in PLAC1-silenced cells. Taken together, the present results indicated that high expression of PLAC1 was associated with poor survival and PLAC1 promoted metastasis via EMT in CC.

Epithelial membrane protein 3 regulates lung cancer stem cells via the TGF‑β signaling pathway

Epithelial membrane protein 3 (EMP3) is a transmembrane glycoprotein that contains a peripheral myelin protein 22 domain. EMP3 first received attention as a tumor suppressor, but accumulating evidence has since suggested that it may exhibit a tumor‑promoting function. Nonetheless, the biological function of EMP3 remains largely unclear with regards to its role in cancer. Herein, it was shown that EMP3 expression is upregulated in non‑small cell lung cancer (NSCLC) cells overexpressing aldehyde dehydrogenase 1 (ALDH1). EMP3 was shown to be involved in cell proliferation, the formation of cancer stem cells (CSCs) and in epithelial‑mesenchymal transition (EMT). The ability to resist irradiation, one of the characteristics of CSCs, decreased when the EMP3 mRNA expression was knocked down using small interfering RNA. In addition, when EMP3 knockdown reduced the migratory ability of cells, a characteristic of EMT. Additionally, it was shown that the TGF‑β/Smad signaling axis was a target of EMP3. EMP3 was found to interact with TGF‑β receptor type 2 (TGFBR2) upon TGF‑β stimulation in lung CSCs (LCSC). As a result, binding of EMP3‑TGFBR2 regulates TGF‑β/Smad signaling activation and consequently affects CSCs and EMT. Kaplan‑Meier analysis results confirmed that patients with high expression of EMP3 had poor survival rates. Taken together, these findings showed that EMP3 may be a potential target for management of LCSCs with high expression of ALDH1, and that EMP3 is involved in TGF‑β/Smad signaling activation where it promotes acquisition of cancerous properties in tumors.

miR‑29a‑3p regulates the epithelial‑mesenchymal transition via the SPARC/ERK signaling pathway in human bronchial epithelial cells

Neutrophilic asthma (NA) is a subtype of asthma that responds poorly to corticosteroid treatment. In certain diseases, microRNA (miR)‑29a‑3p is considered to be a key regulatory molecule for remodeling of the extracellular matrix. However, the effect of miR‑29a‑3p on airway remodeling is unknown. The present study aimed to investigate the role of miR‑29a‑3p in NA. A mouse model of NA was established and these animals were compared to normal controls. Both groups of mice were subjected to lung function tests and histopathological analysis. Human bronchial epithelial cells (16HBE) were grown in culture and incubated with secreted protein acidic rich in cysteine (SPARC) and a miR‑29a‑3p mimic. The expression of miR‑29a‑3p, SPARC and epithelial‑mesenchymal transition (EMT)‑related markers were measured using reverse transcription‑quantitative PCR and western blotting. Luciferase reporter assay was performed to identify the direct regulatory relationship between miR‑29a‑3p and SPARC. miR‑29a‑3p expression was significantly decreased, while SPARC expression was increased in the NA mouse model with a phenotype of EMT. Overexpression of SPARC downregulated the expression of E‑cadherin, while it increased the expression of vimentin in 16HBE cells. miR‑29a‑3p administration reversed the SPARC‑induced effects on E‑cadherin and vimentin expression. Luciferase assays confirmed that SPARC was the target gene for miR‑29a‑3p. Furthermore, SPARC overexpression increased the protein expression of phosphorylated (p)‑ERK, while transfection with miR‑29a‑3p mimics significantly inhibited this increase. The data suggested that EMT in the NA mouse model was associated with decreased levels of miR‑29a‑3p and elevated SPARC. Furthermore, SPARC could induce the formation of EMT in 16HBE cells in vitro and this was directly targeted by miR‑29a‑3p and mediated by p‑ERK, suggesting that miR‑29a‑3p may participate in the airway remodeling of NA.

Silencing the lncRNA NORAD inhibits EMT of head and neck squamous cell carcinoma stem cells via miR‑26a‑5p

Cancer stem cells are closely associated with tumor metastasis or recurrence. According to previous literature reports, microRNA (miR)‑26a has an inhibitory effect on head and neck squamous cell carcinoma (HNSCC), and the long non‑coding RNA (lncRNA) non‑coding RNA activated by DNA damage (NORAD) has been found to interact with miR‑26a‑5p. The present study aimed to investigate the regulation and mechanism of NORAD and miR‑26a‑5p in the epithelial‑mesenchymal transition (EMT) of HNSCC stem cells. An ALDEFLUOR stem cell detection kit, a flow cytometer, a self‑renewal ability test and western blotting were used to sort and identify HNSCC stem cells. The ENCORI website and a dual‑luciferase assay were used to assess the relationship between genes. The mRNA and protein expression levels of NORAD, miR‑26a‑5p and EMT‑related genes were detected via reverse transcription‑quantitative PCR and western blotting. Functional experiments (MTT assay, flow cytometry, wound healing assay and Transwell assay) were conducted to analyze the effects of NORAD and miR‑26a‑5p on HNSCC stem cells. The successfully sorted aldehyde dehydrogenase (ALDH)⁺ cells had a self‑renewal capacity and displayed upregulated expression levels of CD44, Oct‑4 and Nanog. NORAD knockdown, achieved using small interfering (si)RNA, downregulated the expression levels of tumor markers in ALDH⁺ cells. siNORAD inhibited cell vitality, migration and invasion, as well as promoted apoptosis, increased the expression of epithelial cell markers and decreased the expression of interstitial cell markers in HNSCC stem cells. miR‑26a‑5p was a downstream gene of NORAD, and knockdown of miR‑26a‑5p partially offset the regulatory effect of siNORAD on HNSCC stem cells. Collectively, the present study demonstrated that NORAD knockdown attenuated the migration, invasion and EMT of HNSCC stem cells via miR‑26a‑5p.

Ultrasound‑targeted microbubble destruction‑mediated overexpression of Sirtuin 3 inhibits the progression of ovarian cancer

Ultrasound-targeted microbubble destruction (UTMD) has recently been developed as a promising noninvasive tool for organ- and tissue-specific gene or drug delivery. The aim of the present study was to explore the role of UTMD-mediated Sirtuin 3 (SIRT3) overexpression in the malignant behaviors of human ovarian cancer (HOC) cells. Reverse transcription-quantitative PCR was performed to detect SIRT3 mRNA expression levels in normal human ovarian epithelial cells and HOC cell lines; low SIRT3 expression was found in HOC cell lines, and the SKOV3 cell line was used in the following experiments. The SIRT3-microbubble (MB) was prepared, and the effects of ultrasound-treated SIRT3-MB on biological processes of SKOV3 cells were determined. The proliferation, migration, invasion and apoptosis of SKOV3 cells were measured after SIRT3 upregulation by UTMD. Xenograft tumors in nude mice were induced to observe tumor growth in vivo. Upregulation of SIRT3 inhibited the malignant behaviors of SKOV3 cells, whereas UTMD-mediated SIRT3 upregulation further inhibited proliferation, epithelial-mesenchymal transition, invasion and migration, and induced apoptosis of SKOV3 cells, and it also inhibited tumor formation and growth in vivo. Moreover, the present study identified hypoxia inducible factor-1α (HIF-1α) as a target of SIRT3. The present study provided evidence that UTMD-mediated overexpression of SIRT3 may suppress HOC progression through the inhibition of HIF-1α.

RORβ suppresses the stemness of gastric cancer cells by downregulating the activity of the Wnt signaling pathway

Gastric cancer (GC) is the third leading cause of cancer-related mortality and the fifth most common type of cancer worldwide. GC stem cells (GCSCs) have been reported to be responsible for the malignant behavior of GC. However, the key molecular mechanism controlling GCSC function remains unclear. The present study aimed to investigate the function of retinoic acid-related orphan receptor β (RORβ) in GC. The expression levels of RORβ in GC cells and clinical GC tissues were analyzed using western blotting, reverse transcription-quantitative PCR (RT-qPCR) and immunohistochemistry. The association between RORβ expression levels and GCSC markers was analyzed using Gene Set Enrichment Analysis, and GeneChip was performed to identify differentially expressed genes between control and RORβ-overexpressing GC cells. CCK-8 and flow cytometric assays were used to evaluate the effect of RORβ on cell viability and apoptosis, respectively. The effect of RORβ on the self-renewal capacity of GCSCs was measured using a sphere formation assay, the expression levels of induced pluripotent stem (iPS) factors and epithelial-mesenchymal transition (EMT)-related factors were measured by RT-qPCR and western blotting, and the tumorigenic capacity was measured by an in vivo mouse model. Finally, the impact of RORβ on the Wnt signaling pathway was determined using western blotting and a TOP/FOP flash assay. The results revealed that the expression levels of RORβ were downregulated in GC tissues compared with para-carcinoma tissues, and were inversely associated with the expression levels of GCSC markers. The overexpression of RORβ upregulated the expression levels of the pro-apoptotic gene, Bcl-2 like protein 11, which subsequently inhibited the viability and promoted the apoptosis of GC cells. In addition, RORβ decreased the sphere forming ability, and downregulated the expression levels of iPS cell- and EMT-related factors. In vivo, RORβ suppressed the tumorigenic capacity and stemness of GC cells. Mechanistically, RORβ was revealed to decrease the activity of the Wnt/β-catenin signaling pathway in GCSCs. In conclusion, the findings of the present study identified RORβ as a novel suppressor of GCSCs and highlighted the prospect of RORβ as a novel candidate target for stem cell-based GC therapy.

Cancer‑associated fibroblast‑induced M2‑polarized macrophages promote hepatocellular carcinoma progression via the plasminogen activator inhibitor‑1 pathway

Targeting the tumor stroma is an important strategy in cancer treatment. Cancer‑associated fibroblasts (CAFs) and tumor‑associated macrophages (TAMs) are two main components in the tumor microenvironment (TME) in hepatocellular carcinoma (HCC), which can promote tumor progression. Plasminogen activator inhibitor‑1 (PAI‑1) upregulation in HCC is predictive of unfavorable tumor behavior and prognosis. However, the crosstalk between cancer cells, TAMs and CAFs, and the functions of PAI‑1 in HCC remain to be fully investigated. In the present study, macrophage polarization and key paracrine factors were assessed during their interactions with CAFs and cancer cells. Cell proliferation, wound healing and Transwell and Matrigel assays were used to investigate the malignant behavior of HCC cells in vitro. It was found that cancer cells and CAFs induced the M2 polarization of TAMs by upregulating the mRNA expression levels of CD163 and CD206, and downregulating IL‑6 mRNA expression and secretion in the macrophages. Both TAMs derived from cancer cells and CAFs promoted HCC cell proliferation and invasion. Furthermore, PAI‑1 expression was upregulated in TAMs after being stimulated with CAF‑conditioned medium and promoted the malignant behavior of the HCC cells by mediating epithelial‑mesenchymal transition. CAFs were the main producer of C‑X‑C motif chemokine ligand 12 (CXCL12) in the TME and CXCL12 contributed to the induction of PAI‑1 secretion in TAMs. In conclusion, the results of the present study suggested that CAFs promoted the M2 polarization of macrophages and induced PAI‑1 secretion via CXCL12. Furthermore, it was found that PAI‑1 produced by the TAMs enhanced the malignant behavior of the HCC cells. Therefore, these factors may be targets for inhibiting the crosstalk between tumor cells, CAFs and TAMs.

MicroRNA‑198 suppresses tumour growth and metastasis in oral squamous cell carcinoma by targeting CDK4

MicroRNAs (miRNAs/miR) often contribute to the progression of oral squamous cell carcinoma (OSCC) via the regulation of mRNA. The present study aimed to investigate the role of miR‑198 in OSCC pathogenesis and explore the underlying mechanism. Reverse transcription‑quantitative (RT‑q)PCR was performed to determine miR‑198 expression in OSCC tissues and cell lines, and univariate and multivariate analyses were applied to evaluate the survival of patients with OSCC. The effects of miR‑198 on OSCC cell lines were studied in vitro and in vivo. A set of epithelial‑mesenchymal transition (EMT) markers were detected to determine whether miR‑198 was involved in EMT. Lastly, using luciferase assays, a novel target of miR‑198 was identified and the effect of the new target gene of miR‑198 on cell proliferation and invasion was also studied. It was identified that miR‑198 expression was decreased in OSCC tissues and cell lines, and low expression of miR‑198 was associated with poor overall survival and disease‑free survival. Overexpression of miR‑198 appeared to significantly inhibit the proliferation, invasion and EMT of OSCC cells. Moreover, the luciferase assay results showed that miR‑198 interacted with cyclin‑dependent kinase 4 (CDK4) by directly targeting the miRNA‑binding site in the CDK4 sequence, and RT‑qPCR results showed that CDK4 expression was increased in OSCC tissues and cell lines. In addition, transfection of small interfering RNA against CDK4 in OSCC cells showed similar inhibitory effects on cell proliferation, invasion and EMT, whereas CDK4 overexpression in OSCC cells partially reversed the inhibitory effects of the miR‑198 mimic. The present results indicated that miR‑198 suppressed OSCC tumour growth and metastasis by directly targeting CDK4 expression. Thus, miR‑198 may be a potential therapeutic target in the treatment of OSCC.

Tripterygium glycoside suppresses epithelial‑to‑mesenchymal transition of diabetic kidney disease podocytes by targeting autophagy through the mTOR/Twist1 pathway

Tripterygium glycoside (TG) is a traditional Chinese medicine extract with immunosuppressive, anti-inflammatory and anti-renal fibrosis effects. Epithelial-mesenchymal transition (EMT) and cell apoptosis are considered to be the major cause of podocyte injury in diabetic kidney disease (DKD). However, it remains unknown as to whether TG is able to alleviate podocyte injury to prevent DKD progression. Therefore, the present study aimed to clarify the podocyte protective effects of TG on DKD. TG, Twist1 small interfering RNA (siRNA) and Twist1 overexpression vector were added to DKD mouse serum-induced podocytes in vitro. Autophagic and EMT activities were evaluated by immunofluorescence staining and western blot analysis. Apoptotic activity was evaluated by Annexin V-FITC/PI flow cytometric analysis. The results revealed that after treatment with DKD mouse serum, autophagy was decreased, whereas EMT and apoptotic rate were increased, in podocytes. In addition, Twist1 expression was increased in DKD-induced podocytes. Furthermore, following Twist1-small interfering RNA transfection, the DKD-induced podocyte EMT and apoptotic rate were markedly reduced, indicating that Twist1 may be a promising therapeutic target for DKD. The present results also revealed that overexpression of Twist1 increased podocyte apoptosis, although this was decreased after TG treatment, indicating that TG may exhibit a protective effect on podocytes by inhibiting the Twist1 signaling pathway. After the addition of 3-benzyl-5-((2-nitrophenoxy) methyl)-dihydrofuran-2(3H)-one, an activator of mTORC1, the effects of TG on podocyte EMT, apoptosis and the autophagy were reversed. These findings indicated that TG may alleviate EMT and apoptosis by upregulating autophagy through the mTOR/Twist1 signaling pathway in DKD.

SMARCC2 combined with c‑Myc inhibits the migration and invasion of glioma cells via modulation of the Wnt/β‑catenin signaling pathway

Glioma is the most common type of central nervous system tumor. SWItch/sucrose non-fermentable (SWI/SNF) is a tumor suppressor that serves an important role in epithelial-mesenchymal transition (EMT). The present study aimed to identify key molecules involved in the EMT process. SWI/SNF related, matrix associated, actin dependent regulator of chromatin subfamily c member 2 (SMARCC2) is mutated in and its expression is low in multiple types of cancer. SMARCC2 is the core subunit of the chromatin-remodeling complex, SWI/SNF. Relative mRNA SMARCC2 expression levels in human glioma tissue were analyzed via reverse transcription-quantitative PCR, whereas the protein expression levels were determined via immunohistochemistry staining. SMARCC2 expression was knocked down in glioma cells using small interfering RNA (si) and overexpressed by infection with adenovirus vectors carrying SMARCC2 cDNA. Wound healing and Transwell assays were performed to assess cell migration and invasion, respectively. Subsequently, immunofluorescence and western blotting were performed to analyze the expression levels of the oncogene c-Myc, which is associated with SMARCC2. SMARCC2 combines with C-MYC to downregulate its expression. Consistent with the results of the bioinformatics analysis, which revealed that the upregulated expression levels of SMARCC2 were associated with a more favorable prognosis in patients with glioma, the mRNA and protein expression levels of SMARCC2 were significantly upregulated in low-grade glioma tissues compared with high-grade glioma tissues. The results of the wound healing assay demonstrated that cell migration was significantly increased in the siSMARCC2-1/3 groups compared with the negative control (NC) group. By contrast, the migratory ability of cells was significantly reduced following transduction with adenovirus overexpressing SMARCC2, which upregulated the expression of SMARCC2, compared with the lentiviral vector-non-specific control (LVS-NC) group. The Transwell assay results further showed that SMARCC2 overexpression significantly inhibited the migratory and invasive abilities of U87MG and LN229 cells compared with the LVS-NC group. Co-immunoprecipitation assays were subsequently conducted to validate the binding of SMARCC2 and c-Myc; the results demonstrated that the expression of c-Myc was downregulated in adenovirus-transfected cells compared with LVS-NC-transfected cells. The results of the western blotting experiments demonstrated that the expression levels of N-cadherin, vimentin, snail family transcriptional repressor 1 and β-catenin were notably downregulated, whereas the expression levels of T-cadherin were markedly upregulated in cell lines stably overexpressing SMARCC2 compared with the LVS-NC group. In conclusion, the results of the present study suggested that SMARCC2 may inhibit Wnt/β-catenin signaling by regulating c-Myc expression in glioma. SMARCC2 regulates the EMT status of the glioblastoma cell line by mediating the expression of the oncogene C-MYC to inhibit its migration and invasion ability. Thus, SMARCC2 may function as a tumor suppressor or oncogene by regulating associated oncogenes or tumor suppressor genes.

Pinosylvin inhibits migration and invasion of nasopharyngeal carcinoma cancer cells via regulation of epithelial‑mesenchymal transition and inhibition of MMP‑2

Nasopharyngeal carcinoma (NPC) is a tumor located in the nasopharynx with highly invasive and metastatic properties. Metastasis is a primary cause of mortality in patients with NPC. The terpenoid polyphenol pinosylvin is a known functional compound of the Pinus species that exhibits anti‑inflammatory effects; however, the effect of pinosylvin on human NPC cell migration and invasion is unclear. The present study aimed to investigate the functional role of pinosylvin in NPC cells (NPC‑039, NPC‑BM and RPMI 2650). Gap closure and Transwell assay indicated that pinosylvin at increasing concentrations inhibited migration and invasion of NPC‑039 and NPC‑BM cells. In addition to inhibiting the enzyme activity of MMP‑2, pinosylvin also decreased the protein expression levels of MMP‑2 and MMP‑9. Pinosylvin decreased the expression of vimentin and N‑cadherin and significantly increased the expression of zonula occludens‑1 and E‑cadherin in NPC cells. Additionally, pinosylvin suppressed the invasion and migration ability of NPC‑039 and NPC‑BM cells by mediating the p38, ERK1/2 and JNK1/2 pathways. The present results revealed that pinosylvin inhibited migration and invasion in NPC cells.

Endoplasmic reticulum stress promotes epithelial‑mesenchymal transition via the PERK signaling pathway in paraquat‑induced pulmonary fibrosis

Pulmonary fibrosis is the primary reason for mortality in patients with paraquat (PQ) poisoning. Our previous study demonstrated that epithelial-mesenchymal transition (EMT) had a role in PQ-induced pulmonary fibrosis. However, the role of endoplasmic reticulum (ER) stress in PQ-induced EMT remains clear. The present study aimed to determine the role of ER stress in EMT in PQ-induced pulmonary fibrosis. A549 and RLE-6TN cells were incubated with LY294002 (a PI3K inhibitor) or transfected with protein kinase RNA-like ER kinase (PERK) small interfering RNA (si) for 24 h prior to being exposed to PQ. Next, the expression levels of ER stress-related proteins, PI3K/AKT/GSK-3β signaling pathway-related proteins and EMT-related markers were analyzed by performing western blotting, reverse transcription-quantitative PCR and immunofluorescence assays. The results of the present study revealed that the protein expression levels of PERK, phosphorylated (p)-PERK, p-eukaryotic initiation factor 2 (eIF2)α were significantly upregulated in the PQ group, whereas p-PI3K, p-AKT and p-GSK-3β were significantly upregulated in the sicontrol + PQ group compared with the sicontrol group. In vitro, following transfection with siPERK or treatment with the PI3K inhibitor, the protein expression levels of E-cadherin (an epithelial marker) were upregulated, whereas the protein expression levels of α-SMA (a mesenchymal marker) were downregulated. Immunofluorescence analysis revealed that the levels of E-cadherin were markedly upregulated, whereas the levels of α-SMA were notably downregulated following transfection with siPERK compared with the sicontrol group. The results of wound healing assay demonstrated that cell migration in the siPERK + PQ group was markedly decreased compared with the sicontrol + PQ group. These indicated that PQ-induced EMT was suppressed after silencing PERK. The expression levels of p-GSK-3β, p-AKT and p-PI3K were also markedly downregulated in the siPERK + PQ group compared with the sicontrol + PQ group. In conclusion, the findings of the present study suggested that ER stress may promote EMT through the PERK signaling pathway in PQ-induced pulmonary fibrosis. Thus, ER stress may represent a potential therapeutic target for PQ-induced pulmonary fibrosis.

Long noncoding RNA network: Novel insight into hepatocellular carcinoma metastasis (Review)

Hepatocellular carcinoma (HCC) is one of the most common, aggressive malignancies with poor prognosis and high mortality. Although great progress has been made in recent decades, overall survival of HCC patients remains unsatisfactory due to high recurrence and metastasis. Accordingly, understanding and clarifying the underlying molecular mechanisms of metastasis has become increasingly important. Recently, accumulated reports have supported that long noncoding RNAs (lncRNAs) are dysregulated in HCC and are involved in various pivotal biological processes, including metastasis. The aim of this review was to investigate the dysregulation of lncRNAs in HCC and their function as oncogenes or tumour suppressors. Furthermore, reciprocal regulatory networks between lncRNAs and various molecules that were identified in HCC metastasis, including regulating epithelial-mesenchymal transition (EMT), controlling metastasis-associated genes, and regulating tumour angiogenesis were examined. Numerous reports and information on lncRNAs may help identify lncRNAs that are potential novel diagnostic markers, prognostic markers and therapeutic targets.

Phenylethanol glycosides from Herba Cistanche improve the hypoxic tumor microenvironment and enhance the effects of oxaliplatin via the HIF‑1α signaling pathway

Liver cancer is one of the most common types of malignant tumor, and is characterized by high malignancy, rapid progression, high morbidity and mortality. Oxaliplatin (OXA) has been reported to have marked efficiency against advanced liver cancer with tolerable toxicity. In solid tumors, the hypoxic microenvironment promotes epithelial‑mesenchymal transition (EMT), which can also induce drug resistance of liver cancer to platinum drugs. Herba Cistanche (Cistanche tubulosa) has been frequently used in traditional Chinese medicine and the phenylethanol glycosides from Herba Cistanche (CPhGs) are the major active components. The present study aimed to investigate the effects of CPhGs on viability, apoptosis, migration and invasion of liver cancer cells. HepG2 liver cancer cells were divided into the control, DMSO, CoCl₂, OXA, OXA + CoCl₂ and CPhGs + OXA + CoCl₂ groups. Subsequently, reverse transcription‑quantitative PCR and western blot analysis were performed to determine the expression levels of hypoxia‑inducible factor 1α (HIF‑1α), lysyl oxidase‑like 2 (LOXL2) and EMT‑related genes and proteins (i.e., E‑cadherin and Twist), in order to investigate the effects of CPhGs on liver cancer. The results demonstrated that CPhGs could enhance the effects of OXA on liver cancer, and inhibit the migration, invasion and apoptotic rate of liver cancer cells. Additionally, CPhGs treatment effectively induced downregulation of HIF‑1α, LOXL2 and Twist, and upregulation of E‑cadherin. The present findings indicated that CPhGs triggered a significant increase in sensitivity to OXA and suppression of hypoxia‑induced EMT in liver cancer by inhibiting the HIF‑1α signaling pathway. Therefore, CPhGs may be considered an effective platinum drug sensitizer, which could improve chemotherapeutic efficacy in patients with liver cancer.

Neutrophil extracellular traps promote gastric cancer metastasis by inducing epithelial‑mesenchymal transition

The risks of tumor recurrence following the successful resection of the primary tumor have been known for decades; however, the precise mechanisms underlying treatment failures remain unknown. The formation of neutrophil extracellular traps (NETs) has increasingly been demonstrated to be associated with thrombi formation in cancer patients, as well as with the development and metastasis of cancer. The present study demonstrated that the level of peripheral blood NETs in patients with gastric cancer (GC) was associated with tumor progression, and patients with stage III/IV disease exhibited significant differences compared with the healthy controls and patients with stage I/II disease, which may be associated with an increased risk of metastasis. In addition, plasma from patients with stage III/IV GC was more prone to stimulate neutrophils to form NETs; thus, it was hypothesized that the formation of NETs may be affected by the tumor microenvironment. A higher deposition of NETs in GC tissues compared with normal resection margins was also identified. In vitro, following treatment with phorbol myristate acetate, which promotes the formation of NETs, or with DNAse-1/GSK-484, which inhibits the formation of NETs, it was found that the tumor migratory ability was altered; however, no significant changes were observed in cell proliferation and cell cycle progression. Epithelial-mesenchymal transition (EMT) is a key event associated with dissemination and metastasis in GC pathogenesis. Finally, the present study demonstrated that NETs promote a more aggressive mesenchymal phenotype and promote the progression of GC in vitro and in vivo. On the whole, to the best of our knowledge, the present study reports a previously unknown role of NETs in the regulation of GC, which is associated with EMT and migration. Therefore, targeting NETs may prove to be therapeutically beneficial.