Neoplastic spindle cells in nasopharyngeal carcinoma show features of epithelial-mesenchymal transition

Intestinal epithelial SNAI1 promotes the occurrence of colorectal cancer by enhancing EMT and Wnt/β-catenin signaling

Colorectal cancer (CRC) is a prevalent cause of cancer and mortality on a global scale. SNAI1, a member of the zinc finger transcription superfamily, is a significant contributor to embryonic development and carcinogenesis through the process of epithelial-mesenchymal transition (EMT). While prior research utilizing CRC cells and clinical data has demonstrated that SNAI1 facilitates CRC progression through diverse mechanisms, the precise manner in which epithelial SNAI1 regulates CRC development in vivo remains unclear. In this study, colitis and colitis-associated CRC were induced through the use of intestinal epithelium-specific Snai1 knockout (Snai1 cKO) mice. Our findings indicate that Snai1 cKO mice exhibit a reduced susceptibility to acute colitis and colitis-associated CRC compared to control mice. Western-blot analysis of colon tissues revealed that Snai1 cKO mice exhibited a higher overall apoptosis level during tumor formation than control mice. No significant differences were observed in the activation of the classical p53 signaling pathway. However, Snai1 cKO mice exhibited weakened EMT and Wnt/β-catenin pathway activation. In summary, our study has provided evidence in vivo that the intestinal epithelial SNAI1 protein suppresses apoptosis, amplifies the EMT, and activates the Wnt/β-catenin signaling pathways in both early and late phases of CRC formation, thus promoting the development and progression of colitis-associated CRC.

Long Non-Coding RNA Small Nucleolar RNA Host Gene 4 Induced by Transcription Factor SP1 Promoted the Progression of Nasopharyngeal Carcinoma Through Modulating microRNA-510-5p/Centromere Protein F Axis

Long non-coding RNAs (LncRNAs) are implicated with tumorigenesis and the development of nasopharyngeal carcinoma (NPC). Previous studies suggested that long non-coding RNA small nucleolar RNA host gene 4 (SNHG4) exerted oncogenic roles in various cancers. However, the function and molecular mechanism of SNHG4 in NPC have not been investigated. In our study, it was confirmed that the SNHG4 level was enriched in NPC tissues and cells. Functional assays indicated that SNHG4 depletion inhibited the proliferation and metastasis but promoted apoptosis of NPC cells. Furthermore, we identified miR-510-5p as a downstream gene of SNHG4 in NPC cells and SNHG4 upregulated CENPF expression by binding to miR-510-5p. Moreover, there was a positive (or negative) association between CENPF and SNHG4 (or miR-510-5p) expression in NPC. In addition, rescue experiments verified that CENPF overexpression or miR-510-5p silencing abrogated inhibitory effects on NPC tumorigenesis caused by SNHG4 deficiency. The study demonstrated that SNHG4 promoted NPC progression via miR-510-5p/CENPF axis, providing a novel potential therapeutic target for NPC treatments.

Recurrence risk stratification based on Epstein–Barr virus DNA to identify enlarged retropharyngeal lymph nodes of nasopharyngeal carcinoma: A model-histopathologic correlation study

Background

Accurate assessment of the nature of enlarged retropharyngeal lymph nodes (RLN) of nasopharyngeal carcinoma (NPC) patients after radiotherapy is related to selecting appropriate treatments and avoiding unnecessary therapy. This study aimed to develop a non-invasive and effective model for predicting the recurrence of RLN (RRLN) in NPC.

Materials and methods

The data of post-radiotherapy NPC patients (N = 76) with abnormal enlargement of RLN who underwent endonasopharyngeal ultrasound-guided fine-needle aspirations (EPUS-FNA) were examined. They were randomly divided into a discovery (n = 53) and validation (n = 23) cohort. Univariate logistic regression was used to assess the association between variables (magnetic resonance imaging characteristics, EBV DNA) and RRLN. Multiple logistic regression was used to construct a prediction model. The accuracy of the model was assessed by discrimination and calibration, and decision curves were used to assess the clinical reliability of the model for the identification of high risk RLNs for possible recurrence.

Results

Abnormal enhancement, minimum axis diameter (MAD) and EBV-DNA were identified as independent risk factors for RRLN and could stratify NPC patients into three risk groups. The probability of RRLN in the low-, medium-, and high-risk groups were 37.5, 82.4, and 100%, respectively. The AUC of the final predictive model was 0.882 (95% CI: 0.782–0.982) in the discovery cohort and 0.926 (95% CI, 0.827–1.000) in the validation cohort, demonstrating good clinical accuracy for predicting the RRLN of NPC patients. The favorable performance of the model was confirmed by the calibration plot and decision curve analysis.

Conclusion

The nomogram model constructed in the study could be reliable in predicting the risk of RRLN after radiotherapy for NPC patients.

Engrailed homeobox 1 transcriptional regulation of COL22A1 inhibits nasopharyngeal carcinoma cell senescence through the G1/S phase arrest

EN1 is well known as a transcription factor in other tumours, but its role in NPC is unclear. In this study, we first used bioinformatics to analyse GEO data to obtain the differentially expressed gene EN1, and subsequently verified that EN1 was highly expressed in nasopharyngeal carcinoma cells by tissue microarrays as well as cell lines. Further, we down‐regulated the expression of EN1 in cells for RNA sequencing. The analysis of sequencing results using KEGG and GO revealed significant changes in cell proliferation and cycle function after downregulation of EN1. Meanwhile, we found that cells underwent senescence after inhibition of EN1 under electron microscopy and the SA‐β‐gal assays. Based on the sequencing results, we verified that EN1 can promote the proliferation and cycle of NPC cells in cell function experiments and animal experiments. To investigate how EN1 affects cell senescence, we found that EN1 transcriptional regulation of COL22A1 regulated cell proliferation and cycle via CDK4/6‐cyclin D1‐Rb signalling pathway by dual luciferase reporter, Immunoblotting and rescue experiment. Accordingly, we uncovered that EN1 could serve as a target for the regulation of senescence in NPC.

Prognostic significance of AKR1C4 and the advantage of combining EBV DNA to stratify patients at high risk of locoregional recurrence of nasopharyngeal carcinoma

Background

Distinguishing patients at a greater risk of recurrence is essential for treating locoregional advanced nasopharyngeal carcinoma (NPC). This study aimed to explore the potential of aldo–keto reductase 1C4 (AKR1C4) in stratifying patients at high risk of locoregional relapse.

Methods

A total of 179 patients with locoregionally advanced NPC were grouped by different strategies; they were: (a) divided into two groups according to AKR1C4 expression level, and (b) classified into three clusters by integrating AKR1C4 and Epstein-Barr virus (EBV) DNA. The Kaplan–Meier method was used to calculate locoregional relapse-free survival (LRFS), overall survival (OS), progression-free survival (PFS), and distant metastasis-free survival (DMFS). The Cox proportional hazards model was used to determine potential prognostic factors, and a nomogram was generated to predict 3-year and 5-year LRFS.

Results

A significant difference in the 5-year LRFS was observed between the high and low AKR1C4 expression groups (83.3% vs. 92.7%, respectively; p = 0.009). After integrating AKR1C4 expression and EBV DNA, the LRFS (84.7%, 84.5%, 96.9%, p = 0.014) of high-, intermediate-, and low- AKR1C4 and EBV DNA was also significant. Multivariate analysis indicated that AKR1C4 expression (p = 0.006) was an independent prognostic factor for LRFS. The prognostic factors incorporated into the nomogram were AKR1C4 expression, T stage, and EBV DNA, and the concordance index of the nomogram for locoregional relapse was 0.718.

Conclusions

In conclusion, high AKR1C4 expression was associated with a high possibility of relapse in NPC patients, and integrating EBV DNA and AKR1C4 can stratify high-risk patients with locoregional recurrence.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09924-3.

RNF38 suppress growth and metastasis via ubiquitination of ACTN4 in nasopharyngeal carcinoma

Background

Accumulated evidence suggests that RING finger proteins (RNFs) are involved in the carcinogenesis of cancers. However, RNF38, a member of the RNF protein family, has not been studied in nasopharyngeal carcinoma (NPC).

Methods

RNF38 expression was analyzed by RT-PCR, Western blotting and Immunohistochemistry. Biological functions of RNF38 were evaluated by cell growth, colony formation, apoptosis, migration and invasion assays in vitro. Xenograft growth and lung metastasis models were conducted to investigate the effect of RNF38 in vivo. Liquid chromatography coupled with tandem mass spectrometry, co-immunoprecipitation, and CHX assay were implemented to detect the interaction among RNF38 and ACTN4.

Results

RNF38 was significantly downregulated in NPC cells and tissues. Immunohistochemistry implied that loss of RNF38 was an independent prognostic factor for poor outcomes of NPC patients. Gain- and loss-of-function experiments showed that RNF38 inhibited proliferation and metastasis in NPC in vitro and in vivo. Upregulation of RNF38 promoted apoptosis of NPC cells to etoposide but not cisplatin. ACTN4 was upregulated in NPC and negatively correlated with RNF38. Mechanistic investigations suggested that RNF38 inactivates the NF-𝛋B and ERK1/2 signaling pathways by inducing ubiquitination and degradation of ACTN4. RNF38 suppress the development of NPC by interacting with ACTN4.

Conclusions

RNF38 plays a potential cancer suppressor gene role in NPC tumorigenesis and is a prognostic biomarker in NPC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09641-x.

Nasopharyngeal Carcinoma and Its Microenvironment: Past, Current, and Future Perspectives

Nasopharyngeal carcinoma (NPC) is an epithelial malignancy that raises public health concerns in endemic countries. Despite breakthroughs in therapeutic strategies, late diagnosis and drug resistance often lead to unsatisfactory clinical outcomes in NPC patients. The tumor microenvironment (TME) is a complex niche consisting of tumor-associated cells, such as fibroblasts, endothelial cells, leukocytes, that influences tumor initiation, progression, invasion, and metastasis. Cells in the TME communicate through various mechanisms, of note, exosomes, ligand-receptor interactions, cytokines and chemokines are active players in the construction of TME, characterized by an abundance of immune infiltrates with suppressed immune activities. The NPC microenvironment serves as a target-rich niche for the discovery of potential promising predictive or diagnostic biomarkers and the development of therapeutic strategies. Thus, huge efforts have been made to exploit the role of the NPC microenvironment. The whole picture of the NPC microenvironment remains to be portrayed to understand the mechanisms underlying tumor biology and implement research into clinical practice. The current review discusses the recent insights into the role of TME in the development and progression of NPC which results in different clinical outcomes of patients. Clinical interventions with the use of TME components as potential biomarkers or therapeutic targets, their challenges, and future perspectives will be introduced. This review anticipates to provide insights to the researchers for future preclinical, translational and clinical research on the NPC microenvironment.

Identification of DTL as Related Biomarker and Immune Infiltration Characteristics of Nasopharyngeal Carcinoma via Comprehensive Strategies

Purpose

Although considerable progress has been made in basic and clinical research on nasopharyngeal carcinoma (NPC), the biomarkers of the progression of NPC have not been fully studied and described. This study was designed to identify potential novel biomarkers for NPC using integrated analyses and explore the immune cell infiltration in this pathological process.

Methods

Five GEO data sets were downloaded from gene expression omnibus database (GEO) and analysed to identify differentially expressed genes (DEGs), followed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. The four algorithms were adopted for screening of novel and key biomarkers for NPC, including random forest (RF) machine learning algorithm, least absolute shrinkage and selection operator (LASSO) logistic regression, support vector machine-recursive feature elimination (SVM-RFE), and weighted gene co-expression network analysis (WGCNA). Lastly, CIBERSORT was used to assess the infiltration of immune cells in NPC, and the correlation between diagnostic markers and infiltrating immune cells was analyzed.

Results

Herein, we identified 46 DEGs, and enrichment analysis results showed that DEGs and several kinds of signaling pathways might be closely associated with the occurrence and progression of NPC. DTL was recognized as NPC-related biomarker. DTL, also known as retinoic acid-regulated nuclear matrix-associated protein (RAMP), or DNA replication factor 2 (CDT2), is reported to be correlated with the cell proliferation, cell cycle arrest and cell invasion in hepatocellular carcinoma, breast cancer and gastric cancer. Immune infiltration analysis demonstrated that macrophages M0, macrophages M1 and T cells CD4 memory activated were linked to pathogenesis of NPC.

Conclusion

In summary, we adopted a comprehensive strategy to screen DTL as biomarkers related to NPC and explore the critical role of immune cell infiltration in NPC.

Circular RNA SET domain protein 3 promotes nasopharyngeal carcinoma proliferation, cisplatin resistance, and protein kinase B / mammalian target of rapamycin pathway activation by modulating microRNA-147a expression

Circular RNA (circRNA) plays a crucial role in the establishment and progression of nasopharyngeal carcinoma (NPC). Understanding the role of circRNA in NPC is helpful to find new therapeutic targets for NPC. The purpose of this study was to explore the effects of circRNA SET domain protein 3 (circSETD3) on protein kinase B (Akt)/ mammalian target of rapamycin (mTOR) signaling pathway and cisplatin (DDP) resistance to NPC and explore its downstream mechanism. The results showed that circSETD3 was upregulated in NPC tissues and was related to DDP resistance to NPC. Functional experiments revealed that circSETD3 knockdown inhibited NPC proliferation and increased DDP sensitivity and apoptosis rate. The promotion effect of circSETD3 overexpression on NPC proliferation and DDP resistance and inhibition effect on apoptosis was reversed by elevated miR-147a. CircSETD3 knockdown or miR-147a overexpression prevented Akt/mTOR pathway's activation. In terms of the mechanism, circSETD3 acted as a sponge for miR-147a. Xenotransplantation experiments showed that knockdown circSETD3 or DDP treatment could restrain tumor growth, and the effect of DDP was enhanced by knockdown of circSETD3. In conclusion, the results of this study confirm that circSETD3 promotes NPC proliferation and DDP resistance by regulating miR-147a, and circSETD3/miR-147a axis may serve as a potential therapeutic target for NPC in the future.

Computer-Aided Pathologic Diagnosis of Nasopharyngeal Carcinoma Based on Deep Learning

The pathologic diagnosis of nasopharyngeal carcinoma (NPC) by different pathologists is often inefficient and inconsistent. We have therefore introduced a deep learning algorithm into this process and compared the performance of the model with that of three pathologists with different levels of experience to demonstrate its clinical value. In this retrospective study, a total of 1970 whole slide images of 731 cases were collected and divided into training, validation, and testing sets. Inception-v3, which is a state-of-the-art convolutional neural network, was trained to classify images into three categories: chronic nasopharyngeal inflammation, lymphoid hyperplasia, and NPC. The mean area under the curve (AUC) of the deep learning model is 0.936 based on the testing set, and its AUCs for the three image categories are 0.905, 0.972, and 0.930, respectively. In the comparison with the three pathologists, the model outperforms the junior and intermediate pathologists, and has only a slightly lower performance than the senior pathologist when considered in terms of accuracy, specificity, sensitivity, AUC, and consistency. To our knowledge, this is the first study about the application of deep learning to NPC pathologic diagnosis. In clinical practice, the deep learning model can potentially assist pathologists by providing a second opinion on their NPC diagnoses.

Matrix metalloproteinase 2 contributes to aggressive phenotype, epithelial-mesenchymal transition and poor outcome in nasopharyngeal carcinoma

Background

Though matrix metalloproteinase 2 (MMP-2) involvement in tumor aggressiveness and invasion is well-known, its prognostic impacts still remain largely controversial. Furthermore, the correlations between MMP-2 and epithelial-mesenchymal transition (EMT) have not been directly established in nasopharyngeal carcinoma (NPC).

Materials and methods

The purpose of this study was to investigate MMP-2 expression in NPC. Tissue microarrays from 144 patients with NPC and 45 non-cancerous pharynx tissues were analyzed for MMP-2 expression by immunohistochemistry. MMP-2 expression in relation to clinicopathological characteristics and EMT were assessed in NPC. Tumor-invasive potential affected by exogenous expression of MMP-2 in NPC cells was also detected in vitro.

Results

Compared to normal nasopharyngeal epithelium, high expression of tumoral MMP-2 was detected in 47.9% of NPC samples. Significant association was found between MMP-2 expression and various aggressive features including T classification, M classification and tumor stage (P<0.05). Of note, high expression of MMP-2 was prominently observed at tumor invasive front, neoplastic spindle cells migrating into the stroma and vessel invasion. Importantly, high MMP-2 expression predicted worse survival in patients with stage III-IV (P=0.039). Overexpression of MMP-2 could decrease cell-cell adhesion, promote tumor invasion and EMT including downregulation of E-cadherin and upregulation of N-cadherin, Fibronectin and Slug of NPC cells.

Conclusion

Our findings demonstrate that MMP-2 expression contributes to tumor aggressiveness and poor prognosis, and induces the occurrence of EMT in NPC.

The effects of miR-429 on cell migration and invasion by targeting Slug in esophageal squamous cell carcinoma

Increasing evidence indicates that microRNAs may play important roles in tumor development and may take part in different processes in different cancers. miR-429 is known as a cancer suppressor or oncogene that is dysregulated in different malignancies, including esophageal squamous cell carcinoma (ESCC). However, the effect of miR-429 in ESCC has not been fully explored. The purpose of this study was to investigate the functions of miR-429 in ESCC. qRT-PCR assays were performed to detect miR-429 expression in ESCC tissues and cell lines. To assess the effects of miR-429 on ESCC cells, wound healing and transwell assays were used. Luciferase reporter and western blot assays were employed to determine whether Slug is a major target of miR-429.Our results showed that the expression levels of miR-429 in ESCC tissues and cells were lower than in normal esophageal epithelial tissues and cells. Furthermore, overexpression of endogenous miR-429 inhibited the migration and invasion of ESCC cell lines. In addition, Luciferase reporter and western blot assays provided evidence that miR-429 can bind to the 3' untranslated regions of Slug to regulate its expression and that of downstream epithelial-to-mesenchymal transition (EMT) markers. We found that Slug serves as a major target of miR-429. miR-429 plays a vital role in ESCC progression and represents a new therapeutic target for ESCC.

Investigation of specific binding of designed oligodeoxynucleotide decoys to transcription factors in HT29 cell line undergoing epithelial-mesenchymal transition (EMT)

Expression of master transcriptional regulators of stem cells (Oct4 and Sox2) is associated with mediating tumor proliferation and tumor differentiation. The main goal of this study is the investigation of specific binding of designed Oct4-Sox2 transcription factors decoy oligodeoxynucleotides (ODNs) sequence to their nucleus-extracted proteins in HT29-ShE cells containing enriched cancer stem-like cells (SCLCs). First, gene expression of Oct4, Sox2, and E-cadherin revealed the overexpression of Oct4 and Sox2 and downregulation of E-cadherin in HT29-ShE cells compared with HT29 wild-type and HT29-ShC cells. Next, Oct4-Sox2 complex decoy ODNs were designed according to their elements in the promoter region of Sox2 gene. Then, the interactions of Oct4 and Sox2 proteins to designed ODNs were evaluated in silico. Finally, DNA-protein interactions of decoy ODNs and their corresponding proteins were examined by electrophoretic mobility shift assay (EMSA). Analysis of gel shift retardation assay admitted the specific binding of designed ODNs sequence to the nuclear extracted Oct4 and Sox2 proteins. The results will be a promising approach to target cancer stem cells for potential use in differentiation therapy before chemotherapy and radiotherapy of cancers.

Fibronectin 1 promotes melanoma proliferation and metastasis by inhibiting apoptosis and regulating EMT

Background and aims: The complex process of cancer metastasis remains the least understood. Tumor cells alter their protein expression profile to survive from the tumor metastasis. Fibronectin 1 (FN1 gene coding protein) is a member of the glycoprotein family that has been shown to play an important role in cancer metastasis. However, its effects on melanoma metastasis are still unclear. Methods: We detected the FN1 expression between metastatic cells and primary cells by using Western blot and RT-qPCR assays. And, we analyzed the expressed feature of FN1 in different tissues and examined the clinical relevance of upregulated FN1 in melanoma progression by bioinformatic analysis. Furthermore, we downregulated the expression of FN1 by small interfering RNA technique to reveal the effect of FN1 on melanoma phenotype and expression of related genes. Finally, we used bioinformatics to reveal the possible mechanism of FN1 regulating melanoma progression. Results: We reported that the expression of FN1 was changed during melanoma metastasis. In this study, we established two metastatic cell lines of melanoma through mouse model, and found that metastatic cells exhibited stronger mesenchyme phenotype and possessed higher FN1 expression level compared to primary cells. Besides, we examined the clinical relevance of upregulated FN1 in tumor progression. Small interfering RNA (siRNA)-mediated downregulation of FN1 suppressed the migration, invasion, adhesion, proliferation capabilities and induced apoptosis of melanoma cells. We detected a diminished EMT-related gene signature including increased expression of E-cadherin and decreased expression of N-cadherin and Vimentin. Downregulation of FN1 also increased Bax/Bcl-2 ratio which might result in apoptosis of melanoma cells. Bioinformatics analysis revealed that FN1 most likely involved in focal adhesion and PI3K-Akt signaling pathway to regulate EMT process and apoptosis. Conclusions: Taken together, these findings demonstrated a role of FN1 in promoting melanoma metastasis by inhibiting apoptosis and regulating EMT.

Snail-mediated cancer stem cell-like phenotype in human CNE2 nasopharyngeal carcinoma cell

BACKGROUND

Cancer stem cell (CSC)-like phenotype, which has been proven to play a critical role in invasion and metastasis of many kinds of cancers, has also been reported to be associated with epithelial-mesenchymal transition. Snail, a potent repressor of E-cadherin expression, was found to have a function to regulate the aforementioned processes.

METHODS

In the current study, expression of putative CSCs biomarkers and the ratio of CSC-like CNE2 (cancer cell line) in total CNE2 were measured, and CSC-like characteristics were analyzed with tumor-sphere self-renewal and colony-forming assays. Migration and invasion properties were determined by using transwell and wound healing assays. Xenograft tumor assays in vivo were done to evaluate the function of Snail and radiation in the tumor forming ability.

RESULTS

In human nasopharyngeal carcinoma (NPC) cells, overexpression of Snail mediates a CSC-like phenotype, which enhances the initiation, invasion, and migration ability of cancer cells.

CONCLUSION

Thus, Snail is a potential therapeutic target in NPC.

Hippo pathway contributes to cisplatin resistant-induced EMT in nasopharyngeal carcinoma cells

Nasopharyngeal carcinoma (NPC) is a kind of head-neck malignant tumor derived from the nasopharyngeal epithelium and is mainly prevalent in Southern China and Southeast Asia countries. Cisplatin (DDP) provides the first-line therapeutic administration in NPC patients. However, chemoresistance has been a main barrier and caused bad treatment outcome in NPC therapy. To understand the molecular mechanism of acquired resistance to DDP, multiple methods were performed to examine the morphocytology and molecular changes in DDP-resistant NPC cells. We found that drug resistance cells displayed epithelial-mesenchymal transition (EMT) characteristics. DDP-resistant NPC cells exhibited enhanced migration and invasion potential. Moreover, overexpression of TAZ, one key gene in Hippo pathway, is closely associated with the DDP resistance of NPC cells and its EMT properties. Depletion of TAZ in DDP-resistant cells reversed EMT phenotypes to MET characteristics and restored chemosensitivity of DDP-resistant cells to DDP treatment. These results suggest that inactivation of TAZ could be a promising approach for the treatment of NPC patients.

Elevation of MiR-9-3p suppresses the epithelial-mesenchymal transition of nasopharyngeal carcinoma cells via down-regulating FN1, ITGB1 and ITGAV

MicroRNAs had been proved to be pivotal regulators in nasopharyngeal carcinoma (NPC) by regulating a large amount of genes' expression. In our research, we aim to explore the functions of miR-9-3p on the metastases of NPC and figure out the potential mechanisms. First, we revealed downregulation of miR-9-3p and upregulation of fibronectin 1 (FN1), β1 integrin (ITGB1) and α5 integrin (ITGAV) expression in NPC tissues and cells compared with the normal using RNA-seq analysis, RT-qPCR, western blot and immunohistochemistry. By transfection of miR-9-3p mimics in CNE-1, CNE-2 and HONE-1 cells, we confirmed tumor-suppressing roles of miR-9-3p via suppressing EMT process by MTT, wound scratch, transwell assay and western blot. After constructing luciferase reporting plasmids and transient transfection in HEK 293T cells, we proved that FN1, ITGB1 and ITGAV were all targets of miR-9-3p. Then we manipulated the expression of miR-9-3p, FN1, ITGB1 and ITGAV in HONE-1 cells, verifying the tumor-promoting effect of FN1, ITGB1 and ITGAV on cell proliferation and metastases via facilitating EMT process of cells. Additionally, these functions of FN1, ITGB1 and ITGAV could be efficiently abrogated by overexpression of miR-9-3p. Taken together, we demonstrated that elevation of miR-9-3p suppresses the proliferation and metastases of NPC via downregulating FN1, ITGB1, ITGAV and inhibiting the EMT process, which provided a series of therapeutic targets for the treatment of NPC.

High FMNL3 expression promotes nasopharyngeal carcinoma cell metastasis: role in TGF-β1-induced epithelia-to-mesenchymal transition

Formin-like 3 (FMNL3) plays a crucial role in cytoskeletal mediation and is potentially a biomarker for cell migration; however, its role in cancer metastasis remains unknown. In this study, we found elevated FMNL3 protein expression in clinical nasopharyngeal carcinoma (NPC) tissues. FMNL3 expression positively correlated to the clinical stage, T (tumour), N (lymph node metastasis) and M (distant metastasis) classification of NPC patients. Moreover, FMNL3 positively correlated to Vimentin expression and negatively correlated to E-cadherin expression in clinical NPC samples. In vitro experiments showed that FMNL3 expression was inversely related to NPC cell differentiation status. Overexpression of FMNL3 led to epithelial-to-mesenchymal transition (EMT) in well differentiated CNE1 cells. TGF-β1-treated poorly differentiated CNE2 cells showed changes in EMT accompanied by enhanced FMNL3 expression and cell migration. On the contrary, knockdown of FMNL3 partially attenuated the TGF-β1-promoted CNE2 cell migration, together with associated changes in EMT markers. Finally, knockdown of FMNL3 also weakened EMT in tumours in xenographs. Our study indicates for the first time that TGF-β1/FMNL3 signalling may be a novel mechanism mediating EMT in NPC, which is closely associated with NPC metastasis.

P300 promotes migration, invasion and epithelial-mesenchymal transition in a nasopharyngeal carcinoma cell line

A previous study demonstrated that p300 is overexpressed in nasopharyngeal carcinoma (NPC), and that its expression is an independent prognostic factor. The aim of the present study is to investigate the role of p300 in human NPC development. A small hairpin (sh) RNA lentiviral expression vector targeting the p300 gene was constructed to suppress the expression of p300 in NPC cells. Knockdown of p300 was verified by reverse transcription-quantitative polymerase chain reaction and western blotting. Wound-healing, invasion, immunofluorescence and immunoprecipitation assays were performed to assess the influence of p300 on nasopharyngeal tumorigenesis and metastasis in vitro. The expression of p300 was upregulated in NPC cell lines. After knockdown of p300, the migration and invasion ability of shp300 cells were significantly inhibited (P<0.05). Furthermore, the depletion of p300 expression in NPC cell lines resulted in the upregulation of epithelial phenotype marker E-cadherin and α-catenin, and downregulation of mesenchymal phenotype markers N-cadherin and vimentin. p300 promotes epithelial-mesenchymal transition (EMT) through the acetylation of Smad2 and Smad3 in the tumor growth factor-β signaling pathway. In conclusion, p300 may be involved in the invasion and metastasis of NPC through the induction of EMT.

Roles of Signaling Pathways in the Epithelial-Mesenchymal Transition in Cancer

The epithelial-mesenchymal transition (EMT) is a cellular process though which an epithelial phenotype can be converted into a phenotype of mesenchymal cells. Under physiological conditions EMT is important for embryogenesis, organ development, wound repair and tissue remodeling. However, EMT may also be activated under pathologic conditions, especially in carcinogenesis and metastatic progression. Major signaling pathways involved in EMT include transforming growth factor β(TGF-β), Wnt, Notch, Hedgehog and other signaling pathways. These pathways are related to several transcription factors, including Twist, Smads and zinc finger proteins snail and slug. These interact with each other to provide crosstalk between the relevant signaling pathways. This review lays emphasis on studying the relationship between EMT and signaling pathways in carcinogenesis and metastatic progression.

Correlation of overexpression of nestin with expression of epithelial-mesenchymal transition-related proteins in gastric adenocarcinoma

BACKGROUND

Nestin is associated with neoplastic transformation. However, the mechanisms by which nestin contributes regarding invasion and malignancy of gastric adenocarcinoma (GAC) remain unknown. Recent studies have shown that the epithelial-mesenchymal transition (EMT) is important in invasion and migration of cancer cells. In the present study, we aimed to investigate the expression of nestin and its correlation with EMT-related proteins in GAC.

MATERIALS AND METHODS

The expression of nestin and EMT-related proteins was examined in GAC specimens and cell lines by immunohistochemistry and Western blotting. Clinicopathological features and survival outcomes were retrospectively analyzed.

RESULTS

Positive nestin immunostaining was most obviously detected in the cytoplasm, nucleus or both cytoplasm and nucleus of tumor cells in 19.2% (24/125) of GAC tissues, which was significantly higher than that in normal gastric mucosa tissues (1.7%, 1/60) (p=0.001). Nestin expression was closely related to several clinicopathological factors and EMT-related proteins (E-cadherin, vimentin and Snail) and displayed a poor prognosis. Interestingly, simultaneous cytoplasmic and nuclear nestin expression correlated with EMT-related proteins (E-cadherin, vimentin and Snail) (p<0.05) and lymph node metastasis (p=0.041) and a shorter survival time (p<0.05), but this was not the case with cytoplasmic or nuclear nestin expression.

CONCLUSIONS

Nestin, particularly expression in both cytoplasm and nucleus, might be involved in regulating EMT and malignant progression in GAC, with potential as an unfavorable indicator in tumor diagnosis and a target for clinical therapy.

Hes1 triggers epithelial-mesenchymal transition (EMT)-like cellular marker alterations and promotes invasion and metastasis of nasopharyngeal carcinoma by activating the PTEN/AKT pathway

Overexpression of the transcriptional factor Hes1 (hairy and enhancer of split-1) has been observed in numerous cancers, but the precise roles of Hes1 in epithelial-mesenchymal transition (EMT), cancer invasion and metastasis remain unknown. Our current study firstly revealed that Hes1 upregulation in a cohort of human nasopharyngeal carcinoma (NPC) biopsies is significantly associated with the EMT, invasive and metastatic phenotypes of cancer. In the present study, we found that Hes1 overexpression triggered EMT-like cellular marker alterations of NPC cells, whereas knockdown of Hes1 through shRNA reversed the EMT-like phenotypes, as strongly supported by Hes1-mediated EMT in NPC clinical specimens described above. Gain-of-function and loss-of-function experiments demonstrated that Hes1 promoted the migration and invasion of NPC cells in vitro. In addition, exogenous expression of Hes1 significantly enhanced the metastatic ability of NPC cells in vivo. Chromatin immunoprecipitation (ChIP) assays showed that Hes1 inhibited PTEN expression in NPC cells through binding to PTEN promoter region. Increased Hes1 expression and decreased PTEN expression were also observed in a cohort of NPC biopsies. Additional studies demonstrated that Hes1-induced EMT-like molecular changes and increased motility and invasion of NPC cells were mediated by PTEN. Taken together, our results suggest, for what we believe is the first time, that Hes1 plays an important role in the invasion and metastasis of NPC through inhibiting PTEN expression to trigger EMT-like phenotypes.

Hes1 triggers epithelial-mesenchymal transition (EMT)-like cellular marker alterations and promotes invasion and metastasis of nasopharyngeal carcinoma by activating the PTEN/AKT pathway

Overexpression of the transcriptional factor Hes1 (hairy and enhancer of split-1) has been observed in numerous cancers, but the precise roles of Hes1 in epithelial-mesenchymal transition (EMT), cancer invasion and metastasis remain unknown. Our current study firstly revealed that Hes1 upregulation in a cohort of human nasopharyngeal carcinoma (NPC) biopsies is significantly associated with the EMT, invasive and metastatic phenotypes of cancer. In the present study, we found that Hes1 overexpression triggered EMT-like cellular marker alterations of NPC cells, whereas knockdown of Hes1 through shRNA reversed the EMT-like phenotypes, as strongly supported by Hes1-mediated EMT in NPC clinical specimens described above. Gain-of-function and loss-of-function experiments demonstrated that Hes1 promoted the migration and invasion of NPC cells in vitro. In addition, exogenous expression of Hes1 significantly enhanced the metastatic ability of NPC cells in vivo. Chromatin immunoprecipitation (ChIP) assays showed that Hes1 inhibited PTEN expression in NPC cells through binding to PTEN promoter region. Increased Hes1 expression and decreased PTEN expression were also observed in a cohort of NPC biopsies. Additional studies demonstrated that Hes1-induced EMT-like molecular changes and increased motility and invasion of NPC cells were mediated by PTEN. Taken together, our results suggest, for what we believe is the first time, that Hes1 plays an important role in the invasion and metastasis of NPC through inhibiting PTEN expression to trigger EMT-like phenotypes.

Hes1 triggers epithelial-mesenchymal transition (EMT)-like cellular marker alterations and promotes invasion and metastasis of nasopharyngeal carcinoma by activating the PTEN/AKT pathway

Overexpression of the transcriptional factor Hes1 (hairy and enhancer of split-1) has been observed in numerous cancers, but the precise roles of Hes1 in epithelial-mesenchymal transition (EMT), cancer invasion and metastasis remain unknown. Our current study firstly revealed that Hes1 upregulation in a cohort of human nasopharyngeal carcinoma (NPC) biopsies is significantly associated with the EMT, invasive and metastatic phenotypes of cancer. In the present study, we found that Hes1 overexpression triggered EMT-like cellular marker alterations of NPC cells, whereas knockdown of Hes1 through shRNA reversed the EMT-like phenotypes, as strongly supported by Hes1-mediated EMT in NPC clinical specimens described above. Gain-of-function and loss-of-function experiments demonstrated that Hes1 promoted the migration and invasion of NPC cells in vitro. In addition, exogenous expression of Hes1 significantly enhanced the metastatic ability of NPC cells in vivo. Chromatin immunoprecipitation (ChIP) assays showed that Hes1 inhibited PTEN expression in NPC cells through binding to PTEN promoter region. Increased Hes1 expression and decreased PTEN expression were also observed in a cohort of NPC biopsies. Additional studies demonstrated that Hes1-induced EMT-like molecular changes and increased motility and invasion of NPC cells were mediated by PTEN. Taken together, our results suggest, for what we believe is the first time, that Hes1 plays an important role in the invasion and metastasis of NPC through inhibiting PTEN expression to trigger EMT-like phenotypes.

Neoplastic spindle cells are an independent prognostic factor in pancreatic cancer

OBJECTIVE

Several reports showed that neoplastic spindle cells (NSCs) may be strongly involved in the invasion, metastasis, and poor prognosis, as well as in epithelial-mesenchymal transition (EMT). It has not yet been investigated that NSCs relate to the recurrence and prognosis in various cancers. Furthermore, NSCs participate in EMT in pancreatic cancer (PC) too. We clinicopathologically investigated the association between NSCs and the recurrence, prognosis, and EMT in PC.

METHODS

We studied 68 PC patients. Cancer cells with a spindle or oval shape that do not exhibit luminal structures were defined as NSCs. We graded NSCs regarding to an area of NSCs at hematoxylin and eosin stain (NSC grade) and examined the participation in NSCs and EMT by immunohistostaining of snail antibody and E-cadherin antibody.

RESULTS

In multivariate analysis, NSC grade was an independent risk factor for disease-free survival and overall survival. This was independent of TNM stage and histological grade. Neoplastic spindle cells were related to EMT pattern in immunohistostaining significantly.

CONCLUSIONS

Neoplastic spindle cell grade significantly related to the recurrence and prognosis of PC. The NSC grade assessment can be not only performed inexpensively and conveniently, but also used to guide future individualized therapeutic approaches. Furthermore, NSCs were found to relate to EMT profoundly.

Blocking PI3K/Akt signaling attenuates metastasis of nasopharyngeal carcinoma cells through induction of mesenchymal-epithelial reverting transition

In the present study, we evaluated the role of phosphatidylinositol-3 OH kinase/protein kinase B (PI3K/Akt) signaling on changes to epithelial-to-mesenchymal reverting transition (EMrT) in nasopharyngeal carcinoma (NPC). Protein expression levels of p-Akt (Ser473), and the epithelial‑to-mesenchymal transition (EMT) markers E-cadherin, vimentin, α smooth muscle actin (α-SMA), were examined in clinical samples from 130 cases of undifferentiated non-keratinizing NPC, and 20 cases of benign nasopharyngitis. The relationship between protein expression levels and the statue of NPC lymph node metastasis was analyzed. The poorly‑differentiated NPC cell line CNE2Z was treated with various concentrations of the PI3K inhibitor, LY294002, and western blotting and quantitative polymerase chain reaction assays were used to analyze the activation of PI3K/Akt signaling and expression of E-cadherin, vimentin and α-SMA. The ability of cellular migration and invasion was assessed using Transwell assays. The in vivo effects of LY294002 on metastasis and expression of EMT markers in CNE2Z cells was evaluated using tumor xenograft experiments. The expression levels of p-Akt (Ser473) in NPC samples were higher than those in nasopharyngitis. There were reduced levels of membrane E-cadherin protein expression, and increased cytosol vimentin and α-SMA expression levels in NPC samples compared with those in nasopharyngitis samples. High expression levels of p-Akt (Ser473), vimentin, and α-SMA, and low expression levels of E-cadherin were positively associated with lymph node metastasis of NPC cells. Treating CNE2Z cells with LY294002 inhibited p-Akt (Ser473), vimentin and α-SMA expression but upregulated E-cadherin expression, leading to significantly attenuated cell invasion and migration. Administration of mice with LY294002 resulted in upregulation of membrane E-cadherin, and downregulation of vimentin and α-SMA in CNE2Z xenografts, with reduced pulmonary metastasis. Our findings suggest that inhibiting the PI3K/Akt pathway using LY294002 attenuated NPC metastasis via induction of EMrT.

MicroRNA-30a promotes invasiveness and metastasis in vitro and in vivo through epithelial-mesenchymal transition and results in poor survival of nasopharyngeal carcinoma patients

Although microRNA-30a (miR-30a) has been shown to regulate cancer metastasis, the molecular mechanism has not yet been clearly elucidated in nasopharyngeal carcinoma (NPC). The present study was to investigate the miR-30a expression pattern and its potential functions and further to identify its target gene and corresponding clinical applications in NPC. MiR-30a was identified to be down-regulated in NPC primary tumors compared with metastatic tumors using quantitative real-time PCR. Furthermore, over-expression of miR-30a transfected with precursor increased the ability of metastasis and invasion of NPC tumor cells in vivo and in vitro. E-cadherin was screened as a putative target gene of miR-30a by computational algorithms. Luciferase reporter assays showed that over-expression of miR-30a directly reduced the activity of a luciferase transcript combined with the 3'-untranslated region (3'-UTR) of E-cadherin. Kaplan-Meier survival analysis and log-rank test were analyzed for 1077 NPC patients for overall survival, indicating that a high expression of E-cadherin was beneficial for NPC prognosis (P = 0.001). Importantly, NPC patients with high expression of E-cadherin had much lower risk of poor prognosis (hazard ratio = 0.757, P = 0.017) using multivariate analysis. In conclusion, miR-30a could play an important role in regulating NPC metastasis and potentially provide useful guidelines for individualized therapy.

Cancer stem cell characteristics, ALDH1 expression in the invasive front of nasopharyngeal carcinoma

The invasive tumor front underlies the biological aggressiveness and epithelial-mesenchymal transition (EMT) in various human malignances. However, the molecular and biological characteristics of invasive tumor front in NPC have rarely been described. Additionally, the features of cancer stem cells (CSCs) in the invasive front of tumors and its correlation with EMT also remain elusive. Our study was to investigate the expression of CSCs marker aldehyde dehydrogenase 1 (ALDH1) in the invasive front of nasopharyngeal carcinoma (NPC) and its clinical significance. Immunohistochemistry was mainly used to detect ALDH1 expression in the invasive front of NPC. The relationship between ALDH1 expression and EMT-associated markers was also examined. ALDH1 expression in the invasive front correlated strongly with lymphatic invasion (p<0.001), T classification (p=0.001), M classification (p<0.001), clinical stage (p<0.001), and local recurrence (p=0.008). ALDH1 overexpression in the invasive front contributed to worse survival of NPC, particularly in patients with early stage (T1-T2 or N0-N1) (p<0.001 and p=0.002, respectively), though it was not an independent prognostic factor (p=0.196). Furthermore, in the invasive front of NPC, ALDH1 expression correlated significantly with EMT-related biomarkers E-cadherin (p=0.026), Vimentin (p<0.001), Periostin (p<0.001), and Snail (p<0.001), but not with β-catenin (p=0.143). Our findings demonstrate first that ALDH1 expression in the invasive front links closely with EMT characteristics and tumor aggressiveness, which might provide a useful prognostic marker for NPC patients.

Fibronectin overexpression is associated with latent membrane protein 1 expression and has independent prognostic value for nasopharyngeal carcinoma

Despite recent improvements in the diagnosis and treatment, the final outcomes in patients with nasopharyngeal carcinomas (NPC) still remain suboptimal. Through data mining from published transcriptomic database with further bioinformatic validation, fibronectin (FN1) was identified as a differentially upregulated gene in NPC tissues, which implicates the transition from epithelial to mesenchymal phenotype (EMT) and promotes metastasis. Given the roles of fibronectin in risk stratification and in the frontline therapeutics of common carcinomas, such as renal cell cancer, we explored fibronectin immunoexpression status and its associations with clinicopathological variables and survival in a well-defined cohort of NPC patients. Fibronectin immunohistochemistry was retrospectively performed and analyzed using H-score for 124 biopsy specimens from NPC patients who received standard treatment without distant metastasis at initial diagnosis. Those cases with H-score higher than the median value were regarded as fibronectin overexpression. The findings were correlated with clinicopathological variables, EBV latent membrane protein 1 (LMP1) expression, disease-specific survival (DSS), distant metastasis-free survival (DMFS), and local recurrence-free survival (LRFS). Fibronectin overexpression was significantly associated with American Joint Committee on Cancer (AJCC) stages III-IV (p = 0.019) and LMP1 expression (p = 0.004), and univariately predictive of adverse outcomes for DSS, DMFS, and LRFS (all p < 0.0001). In the multivariate comparison, fibronectin overexpression still remained prognostically independent to portend worse DSS (p < 0.01, hazard ratio = 5.958), DMFS (p < 0.01, hazard ratio = 5.728), and LRFS (p < 0.01, hazard ratio = 5.411) together with a vanced AJCC stages III-IV. Fibronectin is upregulated in a subset of NPCs, and its increased immunoexpression significantly correlated with advanced features, justifying the potentiality of fibronectin as a theragnostic biomaker of NPC.

Over-expression of the special AT rich sequence binding protein 1 (SATB1) promotes the progression of nasopharyngeal carcinoma: association with EBV LMP-1 expression

BACKGROUND

Special AT rich sequence binding protein 1 (SATB1) plays a crucial role in the biology of various types of human cancer. However, the role of SATB1 in human nasopharyngeal carcinoma (NPC) remains unknown. In the present study, we sought to investigate the contribution of aberrant SATB1 expression in the progression of NPC and its association with the Epstein Barr virus (EBV)-encoded latent membrane protein 1 (LMP-1).

METHODS

Immunohistochemical analysis was performed to detect SATB1 and LMP-1 protein in clinical samples, and the association of SATB1 protein expression with patient clinicopathological characteristics and LMP-1 expression were analyzed. SATB1 expression profiles were evaluated in well-differentiated NPC cell line CNE1, poorly-differentiated CNE2Z, undifferentiated C666-1 and immortalized nasopharyngeal epithelia NP-69 cells using quantitative RT-PCR, western blotting and fluorescent staining. After inhibition the SATB1 expression by using SATB1 specific small interfering RNA in these cell lines, the change of cell proliferation was investigated by western blotting analysis of PCNA (proliferating cell nuclear antigen) expression and CCK-8 assay, and the cell migration was assessed by Transwell migration assay. Finally, the expressions of SATB1 and PCNA were examined in CNE1 cells that forced LMP-1 expression by fluorescent staining and RT-PCR.

RESULTS

Immunohistochemical analysis revealed that SATB1 protein expression was elevated in NPC tissues compared to benign nasopharyngeal tissues (P = 0.005). Moreover, high levels of SATB1 protein expression were positively correlated with clinical stage (P = 0.025), the status of lymph node metastasis (N classification) (P = 0.018), distant metastasis (M classification) (P = 0.041) and LMP-1 expression status (r = 2.35, P < 0.01) in NPC patients. In vitro experiments demonstrated that an inverse relationship between SATB1 expression and NPC differentiation status, with SATB1 weakly expressed in NP-69 cells and CNE1 cells, and significant increasingly expressed in CNE-2Z and C666-1 cells. Targeted knockdown of SATB1 expression obviously attenuated the proliferation and migration of highly SATB1-expressing CNE2Z and C666-1 cells, but not NP-69 and CNE1 cells. Interestingly, forced LMP-1 expression in CNE1 cells led to a surprisingly increasing SATB1 expression and nuclear location, companying with an up-regulated PCNA expression.

CONCLUSIONS

Our results reveal that EBV LMP-1-mediated over-expression of SATB1 is associated with NPC progression, suggesting SATB1 may represent a promising biomarker and therapeutic target for NPC.

Epithelial-to-mesenchymal transition: immunohistochemical investigation of related molecules in canine cutaneous epithelial tumours

BACKGROUND

Epithelial-to-mesenchymal transition (EMT) is a multistep process, important in tumour invasion and metastasis, characterized by loss of epithelial markers, redistribution of β-catenin and gain of mesenchymal markers. HYPOSTHESIS/OBJECTIVES: Our aim was to investigate the immunohistochemical aberrant expression of cytokeratin, vimentin, survivin and heat shock protein 72 (Hsp72) in canine cutaneous epithelial tumours, to understand the association of expression of these molecules with features of malignancy and their role in the EMT phenotype.

METHODS

Ten canine squamous cell carcinomas (SCCs; one with lymph node metastasis), 30 canine hair follicle tumours (six pilomatricomas, eight infundibular keratinizing acanthomas, six trichoepitheliomas and 10 trichoblastomas) and five normal skin samples were investigated by immunohistochemistry using specific anti-vimentin, -cytokeratin, -survivin and -Hsp72 antibodies. A semi-quantitative method was used to analyse the results, as follows: 0 to <5%; ≥ 5 to <10%; ≥ 10 to <25%; and ≥ 25% of positive cells. Immunofluorescence was performed to investigate survivin-vimentin and survivin-Hsp72 colocalization in selected SCCs. Results - In malignant hair follicle tumours and SCCs, a reduced intensity of cytokeratin and increased survivin and Hsp72 expression were observed. In SCCs, loss of cytokeratin expression and vimentin immunolabelling, suggestive of the EMT phenotype, were evident in <5% of neoplastic cells in the front of tumour invasion. In the same areas, strong nuclear survivin and cytoplasmic Hsp72 staining was evident, often colocalizing. Only a few neoplastic cells in the front of tumour invasion showed vimentin-survivin colocalization.

CONCLUSIONS AND CLINICAL IMPORTANCE

A possible simultaneous involvement of survivin and Hsp72 in tumour invasion and the multistep process of EMT of cutaneous epithelial tumours of dogs is suggested.

Aldehyde dehydrogenase 1, a functional marker for identifying cancer stem cells in human nasopharyngeal carcinoma

Aldehyde dehydrogenase 1 (ALDH1) activity has now been employed successfully as a cancer stem cells (CSCs) marker in various tumors. We wanted to investigate whether ALDH1 can be used as a putative CSCs marker and a powerful prognostic factor in nasopharyngeal carcinoma (NPC). Here, we isolated ALDH1-positive cells from human NPC cell lines (5-8F and CNE2) and found that ALDH1-positive cancer cells grew faster and had higher clone formation efficiency (0.435±0.15; 0.431±0.025 vs. 0.131±0.007; 0.121±0.126), differentiation capability and had higher migration (233.00±5.29; 228.60±9.34 vs. 123.20±7.70 vs. 97.20±6.61) than those of ALDH1-negative cancer cells in vitro. In addition, ALDH1- positive cancer cells formed significantly more tumor spheres. Our in vivo experiments showed that only 5×10(3) ALDH1-positive NPC cells were required to induce tumors. Notably, ALDH1-positive cells are enriched in the side-population (SP) cells, and stem cells-like genes OCT4, BMI1, KLF4 and SOX2 are preferentially expressed in ALDH1-positive cells. Immunohistochemical results showed that the expression of ALDH1 correlated significantly with T classification (P=0.011), N classification (P=0.005), M classification (P=0.002) and clinical stage (P=0.001). Interestingly, ALDH1 expression in the tumor correlated significantly with epithelial-mesenchymal transition (EMT) markers including vimentin expression and loss of E-cadherin (P=0.003 and 0.008, respectively). Furthermore, multivariate analyses showed that ALDH1 expression was an independent prognostic indicator (P=0.032). Taken together, for the first time, we demonstrate that ALDH1 could be a novel stem cells marker and a valuable predictor of poor survival NPC.

Embryonic stem cells markers SOX2, OCT4 and Nanog expression and their correlations with epithelial-mesenchymal transition in nasopharyngeal carcinoma

Expression of embryonic stem cells (ESCs) markers (SOX2, OCT4, Nanog and Nestin) is crucial for progression of various human malignancies. The purpose of this study was to investigate the expression and prognostic impact of these molecules in nasopharyngeal carcinoma (NPC) patients by immunohistochemistry and immunofluorescence. In the present study, we found that the expression levels of SOX2, OCT4 and Nanog were highly expressed in NPC compared with the non-tumorous tissues. Furthermore, these proteins correlated significantly with several clinicalpathological factors and epithelial-mesenchymal transition (EMT)-associated indicators (E-cadherin/N-cadherin and Snail). In multivariate analyses, high expression of OCT4 (P = 0.013) and Nanog (P = 0.040), but not that of SOX2, was associated with worse survival and had strongly independent prognostic effects. Of note, OCT4 and Nanog were more frequently located at the invasive front of tumors, and correlated significantly with various aggressive behaviors including T classification, N classification, M classification and clinical stage. Furthermore, patients with co-expression of OCT4 and Nanog in the invasive front had significantly worse survival (P = 0.005). Interestingly, at the invasive front, these molecules correlated significantly with Nestin expression in endothelial cells (P<0.001). These findings provide evidence that ESCs biomarkers OCT4 and Nanog serves as independent prognostic factors for NPC. Additionally, cancer cells in the invasive front of NPC acquiring ESCs-like features should be maintained by vascular niches.

Molecular characterization and clinical implications of spindle cells in nasopharyngeal carcinoma: a novel molecule-morphology model of tumor progression proposed

Up to now, the precise molecular and morphological changes underlying the invasive and metastatic properties of nasopharyngeal carcinoma (NPC) remain largely unresolved. We speculate that neoplastic spindle cells, which are prominently found in the invasive tumor front and the surrounding stroma, might be responsible for the aggressive patterns. Expression profiling of various biomarkers relevant to cancer stem cells (CSCs) and epithelial-mesenchymal transition (EMT) was performed by tissue microarray-based immunohistochemistry in NPC samples. The expression of EBER and LMP1 was detected by in situ hybridization and immunohistochemistry, respectively. We found that overexpression of CSCs-related markers (ALDH1, Nanog and ABCG2) and up-regulation of EMT markers (Fibronectin, MMP-2, Periostin, SPARC, Snail and Slug), together with E- to N-cadherin switching, occurred preferentially in tumors containing a large proportion of spindle-shaped malignant cells. Furthermore, CSCs-like properties were highly present in spindle cells compared with non-spindle cells of tumors, and correlated strongly with EMT features. In addition, EBV-related factors EBER and LMP1 were highly expressed and correlated strongly with CSCs and EMT characteristics in neoplastic spindle cells. Importantly, high proportion of spindle cells (≥20%) correlated significantly with various aggressive aspects including lymph node metastasis (P = 0.031) and local recurrence (P = 0.014). Patients with high proportion of spindle cells had poor survival (P = 0.004), though it was not an independent value. In conclusion, we demonstrate that spindle cells could be valuable morphological indicators of tumor progression and unfavorable prognosis of NPC. An integrated molecule-morphology model of NPC firstly constructed may shed significant light on the metastatic cascade and clinical relevance of patients.

Tumour budding and the expression of cancer stem cell marker aldehyde dehydrogenase 1 in nasopharyngeal carcinoma

AIMS

To detect the prognostic significance of tumour budding and its expression of aldehyde dehydrogenase 1 (ALDH1) in nasopharyngeal carcinoma (NPC).

METHODS AND RESULTS

Tumour budding was investigated in 105 patients with NPC by immunohistochemistry for pan-cytokeratin (AE1/AE3). The intensity of budding correlated strongly with T classification (P=0.008), lymphatic invasion (P<0.001), vascular invasion (P=0.029), lymph node metastasis (P < 0.001), and clinical stage (P=0.010). Univariate analysis revealed that patients with high budding grade had poorer survival than those with low grade (P=0.002). Multivariate analysis showed that tumour budding was an independent predictor of survival (P=0.001). Furthermore, budding cells showed high-level expression of the cancer stem cell (CSC) marker ALDH1. Budding cells with high-level ALDH1 expression contributed to several aggressive behaviours and poor survival (P=0.000).

CONCLUSIONS

  We describe, for the first time, the presence of tumour budding and its correlation with aggressive tumour behaviour and poor patient survival in NPC. The degree of tumour budding could be a valuable predictive factor in NPC. In addition, we show, also for the first time, that budding cells in NPC might possess the invasive and metastatic properties of CSCs.

Aberrant expression of nuclear vimentin and related epithelial-mesenchymal transition markers in nasopharyngeal carcinoma

Expression of vimentin and the epithelial to mesenchymal transition (EMT) markers E-cadherin, β-catenin is essential for the progression of various human cancers. Our study aimed to investigate the aberrant localization E-cadherin, β-catenin and vimentin, and their prognostic significance in 122 nasopharyngeal carcinoma (NPC) patients by immunohistochemistry and immunofluorescence. Our results showed that both membranous and cytoplasmic localization of E-cadherin staining were associated with lymph node metastasis (p = 0.000 and 0.005, respectively) and clinical stage (p = 0.000 and 0.007, respectively). High cytoplasmic β-catenin correlated significantly with larger tumor size (p = 0.020), lymph node metastasis (p = 0.000) and advanced clinical stage (p = 0.036). However, no significant difference was observed between membranous β-catenin and clinicopathologic features (p ≥ 0.05). High nuclear vimentin expression correlated significantly with positive lymph node metastasis (p = 0.000) and advanced clinical stage (p = 0.000). Multivariate analysis showed that nuclear vimentin and cytoplasmic E-cadherin were independent prognostic factors (p = 0.016 and 0.001, respectively), as well as M classification (p = 0.001). More importantly, patients with high coexpression of nuclear vimentin and cytoplasmic E-cadherin had shorter survival time (p = 0.000). Furthermore, high coexpression of these two proteins was closely associated with lymph node metastasis (p = 0.000) and advanced clinical stage (p = 0.000). Our studies provide convincing evidence that EMT may play an important role in the biological progression of NPC, and nuclear vimentin and cytoplasmic E-cadherin might have independent prognostic value in NPC patients and serve as novel targets for prognostic therapeutics.

High expression of nuclear Snail, but not cytoplasmic staining, predicts poor survival in nasopharyngeal carcinoma

BACKGROUND

Transcription factor Snail has been shown to promote tumor progression and metastasis in various cancers. However, its clinical significance in nasopharyngeal carcinoma (NPC) is still scanty. We have explored the clinical significance of Snail expression and its association with patient outcome in NPC.

METHODS

Immunohistochemistry was used to examine the expression levels of Snail in 122 patients with NPC.

RESULTS

Cytoplasmic Snail was detected in 37.7 %, and nuclear staining was detected in 49.2 % of primary tumors, respectively. No significant associations were found between cytoplasmic Snail and the clinicopathologic variables except lymph node metastasis (P = 0.042). However, nuclear Snail was significantly associated with tumor stage (P = 0.003), T classification (P = 0.045), lymph node metastasis (P = 0.019), distant metastasis (P = 0.003), and reduced E-cadherin expression (P = 0.021). Patients with high nuclear Snail expression, but not cytoplasmic staining, had significantly shorter survival than those with low expression (P < 0.001). Significantly, nuclear Snail was an independent prognostic predictor for NPC (P < 0.001). Furthermore, the prognostic impact was largely limited to stage III-IV patients.

CONCLUSIONS

We demonstrated first that nuclear Snail, but not cytoplasmic staining, predicts worse outcome. In addition, the prognostic value in stage III-IV suggests that nuclear Snail could be a potential therapeutic target for late stage of NPC patients.