Expression of EMMPRIN in adenoid cystic carcinoma of salivary glands: correlation with tumor progression and patients' prognosis

The Role of BTBD7 in Normal Development and Tumor Progression

BTB/POZ domain-containing protein 7 (BTBD7) has a relative molecular weight of 126KD and contains two conserved BTB/POZ protein sequences. BTBD7 has been shown to play an essential role in normal human development, precancerous lesions, heat-stress response, and tumor progression. BTBD7 promotes branching morphogenesis during development and participates in the salivary gland, lung, and tooth formation. Furthermore, many studies have shown that aberrant expression of BTBD7 promotes heat stress response and the progression of precancerous lesions. BTBD7 has also been found to play an important role in cancer. High expression of BTBD7 affects tumor progression by regulating multiple pathways. Therefore, a complete understanding of BTBD7 is crucial for exploring human development and tumor progression. This paper reviews the research progress of BTBD7, which lays a foundation for the application of BTBD7 in regenerative medicine and as a biomarker for tumor prediction or potential therapeutic target.

The Impact of Angiogenesis in the Most Common Salivary Gland Malignant Tumors

Salivary gland carcinomas (SGCs) represent a group of rare tumors, with complete surgical resection being the main treatment option. Therapeutic armory for cases of locally aggressive, recurrent, and/or metastatic SGCs, though, remains poor since they exhibit high rates of resistance to systematic therapy. Angiogenesis is considered one of the contemporary hallmarks of cancer and anti-angiogenic factors have already been approved for the treatment of several cancer types. This review aims to summarize, in a histotype-specific manner, the most current available data on the angiogenic factors implicated in SGC angiogenesis, in order to highlight the differences between the most common SGC histotypes and the factors that may have a potential role as therapeutic targets.

CCL2/CCR2 Axis Promotes the Progression of Salivary Adenoid Cystic Carcinoma via Recruiting and Reprogramming the Tumor-Associated Macrophages

Objective: The present study investigated the roles and underlying mechanism of CCL2/CCR2 axis in the interactions between tumor cells and tumor-associated macrophages (TAMs) during the progression of salivary adenoid cystic carcinoma (SACC). Methods: Immunohistochemical staining and survival analysis were performed to study the correlation and clinical value of CD68, CD163, CCL2, and CCR2 expression in SACC cases. CCL2 silencing by RNA interference and CCR2 blocking by CCR2 specific antagonist (RS504393) were performed. ELISA, qRT-PCR, western blot, immunofluorescence, flow cytometry, CCK8, scratch wound healing, and transwell assays were used to explore the functional roles and possible mechanism of CCL2/CCR2 axis in the interactions between SACC cells and TAMs. The effects of targeting TAMs by blocking the CCL2/CCR2 axis were investigated in a xenograft mice model with SACC cells. Results: The high infiltration of TAMs marked by CD68 and high infiltration of M2 TAMs marked by CD163 were significantly correlated with the expression of CCL2 and CCR2 in SACC tissues. Notably, the high infiltration of TAMs and the overexpression of CCL2 were obviously associated with the clinical progression and poor prognosis of SACC. SACC cells derived CCL2 could activate its receptor CCR2 expression in TAMs in vitro. The in vitro results further indicated that the SACC cells derived CCL2 was involved in the recruitment, M2 polarization, and GDNF expression of TAMs through the CCL2/CCR2 axis. Meanwhile, TAMs derived GDNF promoted the proliferation, migration, and invasion of SACC cells through the GDNF/p-RET pathway. Treating immunodeficient mice with the CCR2 antagonist (RS504393) greatly inhibited the infiltration of TAMs and the tumorigenicity of SACC cells. Conclusion: These new findings indicated that the CCL2/CCR2 axis promoted the progression of SACC cells via recruiting and reprogramming TAMs. Targeting TAMs by blocking the CCL2/CCR2 axis might be a prospective strategy for SACC therapy.

Overexpression Cathepsin D Contributes to Perineural Invasion of Salivary Adenoid Cystic Carcinoma

Objective: Cathepsin D (CTSD) is a pivotal orchestrator in the occurrence and development of tumors. Recently, CTSD was detected in salivary adenoid cystic carcinoma (SACC). However, its functional role in perineural invasion (PNI) of SACC remained elusive. We conducted the present study to detect the expression of CTSD in SACC, analyze the correlation between CTSD expression and prognosis of SACC patients and elucidate the role of CTSD in occurrence of PNI in SACC to lay the foundation for further studies.

Methods: Immunohistochemical analysis was conducted to assess CTSD and Ki67 expression in 158 SACC samples and 20 normal salivary gland samples adjacent to carcinoma. Meanwhile, the correlation between CTSD and PNI of SACC specimens was analyzed using Wilcoxon test. QRT-PCR, immunofluorescence and western blot analysis were used to examine the levels of CTSD mRNA and protein in SACC-LM cell line. SiRNA-mediated CTSD silence was performed. Scratch wound healing assay, transwell invasion assay and DRG co-culture assay of PNI was used to detect the ability of migration, invasion and PNI. FITC-phalloidin was used to detect cytoskeletal organization.

Results: Our data demonstrated that the positive expression of CTSD was observed in 74.1% (117/158) of SACC cases, and the expression of CTSD was significantly correlated with the PNI (p < 0.05). The ability of migration, invasion, and PNI could be inhibited significantly by siRNA-mediated CTSD silence (p < 0.01). Furthermore, siRNA-mediated CTSD silence inhibited cytoskeletal organization and pseudo foot formation in SACC-LM cells.

Conclusion: Our results suggested that an association between PNI and expression of CTSD existed. CTSD may promote PNI of SACC accompanied by cytoskeletal organization and pseudo foot formation.

Functions of chemokines in the perineural invasion of tumors (Review)

The perineural invasion (PNI) of malignant tumors is a form of tumor progression in which cancer cells encroach along nerves. PNI hinders curative resection. Residual tumor cells in or around nerves can bring about local recurrence, infiltration and metastasis. This behavior is usually associated with a poor clinical prognosis. Therefore, it is necessary to investigate novel ligand-receptor crosstalk between nerves and tumor cells that promote the process of PNI. Chemokines are regarded as one of pivotal factors involved in the process of PNI. The present review collates information provided by previous studies with regard to the role of chemokines in PNI. The study presents a definition of PNI in cancer, generalizes the biological characteristics and the expression of chemokines and their receptors in cancer types associated with PNI, and discusses the underlying molecular mechanisms of chemokines, the reciprocal interactions between chemokines and other factors in PNI, and the interconnectivity of the microenvironment and chemokines. The aim of the review is to thoroughly illustrate the molecular cues of chemokines in cancer with PNI and to identify novel antitumor targets.

Expression of PIM-1 in salivary gland adenoid cystic carcinoma: Association with tumor progression and patients' prognosis

Pim-1 proto-oncogene, serine/threonine kinase (PIM-1) phosphorylates a series of substrates to exert its oncogenic function in numerous malignancies. The present study investigated the clinical significance of the PIM-1 protein, apoptosis status and apoptosis-associated proteins, including forkhead box O3a (FOXO3a), B cell lymphoma-2 (BCL-2) and BCL-2-associted agonist of cell death (BAD), were investigated in salivary gland adenoid cystic carcinoma (ACC) tissues. PIM-1 expression levels in 4 pairs of ACC tissues and corresponding normal salivary gland tissues were determined by western blot analysis. PIM-1, FOXO3a, BAD and BCL-2 expression levels in 60 ACC tissues were evaluated by immunohistochemistry (IHC). A terminal deoxynucleotidyl-transferase-mediated dUTP nick end labeling assay was performed to detect the apoptosis status of ACC tissues. PIM-1 was revealed to be highly expressed in ACC tissues compared with adjacent normal tissues. IHC staining results demonstrated high expression ratios of PIM-1, FOXO3a, BCL-2 and BAD [33.33% (20/60), 51.67% (31/60), 51.67% (31/60) and 55% (33/60)], respectively, and significant correlations between the expression of PIM-1 and FOXO3a and BCL-2 (P<0.05). Apoptotic rates were significantly associated with PIM-1, FOXO3a, BCL-2 and BAD expression levels (P<0.05). PIM-1 expression levels were significantly associated with tumor size, lymph node involvement, nerve invasion, distant metastasis and weakly associated with tumor node metastasis stage. Kaplan-Meier survival curves revealed that PIM-1 expression level was significantly associated with disease-free survival of patients with ACC (P=0.009). Cox regression multivariate analysis results revealed that histotype, distant metastasis and apoptotic rate were independent prognosis factors for ACC. Assessment of PIM-1 may be useful in investigating the malignant behaviors of ACC and predicting the outcome of patients with ACC.

The clinicopathological significance and prognostic value of EMMPRIN overexpression in cancers: evidence from 39 cohort studies

Extracellular matrix metalloproteinase inducer (EMMPRIN) has been reported to be associated with tumor formation and invasion in many studies. However, the clinicopathological significance and prognosis of EMMPRIN in cancer patients remains inconclusive. Therefore, we conducted a meta-analysis to assess the predictive potential of EMMPRIN in various cancers. By searching Pubmed, Cochrane library database and web of science comprehensively, 39studies with 5739 cases were included in our meta-analysis. The results indicated that EMMPRIN overexpression was significantly associated with poor outcome of cancers (HR=2.46, 95% CI: 2.21-2.75, P<0.0001). In addition, a significant relation was found between EMMPRIN overexpression and clinicopathological features, such as tumor stage (T3+T4/ T1+T2, OR=1.87, 95% CI:1.64-2.12, P<0.0001), tumor differentiation (poor/ well+ moderate, OR=1.09, 95% CI:1.60-2.23, P<0.0001), clinical stage (III+IV /I +II, OR=1.96, 95% CI:1.69-2.27, P<0.0001) and nodal metastasis (positive/negative, OR=2.37, 95% CI:1.93-2.90, P<0.0001). However, the expression of EMMRIN was not significantly associated with tumor stage in cervical cancer (OR=1.35, 95%CI: 0.73-2.48, P=0.33). In conclusion, EMMPRIN overxepression is significantly associated with clinicopathological characteristics and prognosis of cancers. Thus, EMMPRIN may be regarded as a promising bio-marker in predicting the clinical outcome of patients in cancers and could be used as the therapeutic target during clinical practices.

CD147/EMMPRIN overexpression and prognosis in cancer: A systematic review and meta-analysis

CD147/EMMPRIN (extracellular matrix metalloproteinase inducer) plays an important role in tumor progression and a number of studies have suggested that it is an indicator of tumor prognosis. This current meta-analysis systematically reevaluated the predictive potential of CD147/EMMPRIN in various cancers. We searched PubMed and Embase databases to screen the literature. Fixed-effect and random-effect meta-analytical techniques were used to correlate CD147 expression with outcome measures. A total of 53 studies that included 68 datasets were eligible for inclusion in the final analysis. We found a significant association between CD147/EMMPRIN overexpression and adverse tumor outcomes, such as overall survival, disease-specific survival, progression-free survival, metastasis-free survival or recurrence-free survival, irrespective of the model analysis. In addition, CD147/EMMPRIN overexpression predicted a high risk for chemotherapy drugs resistance. CD147/EMMPRIN is a central player in tumor progression and predicts a poor prognosis, including in patients who have received chemo-radiotherapy. Our results provide the evidence that CD147/EMMPRIN could be a potential therapeutic target for cancers.

Prognostic Indications of Elevated MCT4 and CD147 across Cancer Types: A Meta-Analysis

Background. Metabolism in the tumor microenvironment can play a critical role in tumorigenesis and tumor aggression. Metabolic coupling may occur between tumor compartments; this phenomenon can be prognostically significant and may be conserved across tumor types. Monocarboxylate transporters (MCTs) play an integral role in cellular metabolism via lactate transport and have been implicated in metabolic synergy in tumors. The transporters MCT1 and MCT4 are regulated via expression of their chaperone, CD147. Methods. We conducted a meta-analysis of existing publications on the relationship between MCT1, MCT4, and CD147 expression and overall survival and disease-free survival in cancer, using hazard ratios derived via multivariate Cox regression analyses. Results. Increased MCT4 expressions in the tumor microenvironment, cancer cells, or stromal cells were all associated with decreased overall survival and decreased disease-free survival (p < 0.001 for all analyses). Increased CD147 expression in cancer cells was associated with decreased overall survival and disease-free survival (p < 0.0001 for both analyses). Few studies were available on MCT1 expression; MCT1 expression was not clearly associated with overall or disease-free survival. Conclusion. MCT4 and CD147 expression correlate with worse prognosis across many cancer types. These results warrant further investigation of these associations.

Slug silencing inhibited perineural invasion through regulation of EMMPRIN expression in human salivary adenoid cystic carcinoma

Salivary adenoid cystic carcinoma (SACC) is the most frequent salivary gland malignancy with a unique characteristic that has been named perineural invasion (PNI). EMMPRIN is a transmembrane glycoprotein that has been demonstrated to promote PNI in SACC. Slug, one of the most effective promoters of the epithelial-to-mesenchymal transition (EMT), has been found to be associated with PNI in SACC. The aim of the present study was to investigate the roles and relationships of Slug, EMMPRIN, and E-cadherin in the PNI process of SACC. The expression levels of Slug, EMMPRIN, and E-cadherin in 115 primary SACC cases were statistically analyzed by immunohistochemistry. Simultaneously, the SACC cell line SACC-83 was transfected with recombinant plasmids of silencing Slug (si-Slug) and/or silencing EMMPRIN (si-EMMPRIN). The functions of Slug and EMMPRIN in the EMT and PNI process were assessed by reverse transcription PCR (RT-PCR), western blotting, morphological observation, scratch test, migration assay, and in vitro perineural invasion assay. The immunohistochemical statistics revealed that the high expression of Slug and EMMPRIN and the low expression of E-cadherin were significantly associated with the PNI of SACC (P < 0.05). Slug expression was significantly associated with EMMPRIN expression (P < 0.05), and Slug expression and EMMPRIN expression were both significantly negatively associated with E-cadherin expression (P < 0.05). Slug and EMMPRIN silencing both significantly inhibited EMMPRIN expression but promoted E-cadherin expression in SACC-83 cells (P < 0.01). The series of in vitro assays revealed that silencing of Slug, EMMPRIN, or both induced cell morphology changes and inhibited tumor cell motility and PNI ability in SACC-83 cells (P < 0.01). These results suggested that Slug silencing could inhibit the EMT process by downregulating EMMPRIN and then upregulating E-cadherin in the PNI process of SACC. The present study indicated that Slug and EMMPRIN are potential biomarkers and therapeutic targets for the diagnosis and treatment of PNI in human SACC.

PRL-3 promotes migration and invasion and is associated with poor prognosis in salivary adenoid cystic carcinoma

BACKGROUND

PRL-3 had been found to be involved in tumorigenesis in various malignancies. In this study, we investigated the role of PRL-3 in the development, migration, and invasion of salivary adenoid cystic carcinoma (SACC).

METHODS

Immunohistochemistry (IHC) was used to analyze the role of PRL-3 in the development and prognosis of SACC. Then, we overexpressed or inhibited the expression of PRL-3 in paired SACC cells to analyze the role of PRL-3 in the migration and invasion of SACC. In vitro migration and invasion assays were used. Western blotting was used to detect metastasis-related protein levels.

RESULTS

IHC results confirmed that the deregulation of PRL-3 was a frequent event in SACC; the upregulation of PRL-3 was related to clinical stages, vital status, and distant metastasis, which was associated with reduced overall survival and disease-free survival. SACC-LM cells with higher migratory and invasive abilities had more robust PRL-3 protein expression than SACC-83 cells with lower migratory and invasive abilities. PRL-3 overexpression promoted cell migration, invasion, and proliferation, led to simultaneous upregulation of phosphorylated PRL-3, pERK1/2, Slug, vimentin, and downregulation of E-cadherin in SACC-83 cells. However, the inhibition of PRL-3 by PRL-3 inhibitor or PRL-3 siRNA in SACC-LM cells inhibited cell migration, invasion, and proliferation, resulted in simultaneous downregulation of phosphorylated PRL-3, pERK1/2, Slug, vimentin, and upregulation of E-cadherin.

CONCLUSIONS

Our results confirm that PRL-3 plays an important role in the development of SACC and contributes to the migratory and invasive abilities of SACC.

Vascular endothelial growth factor immunoexpression is increased in malignant salivary gland tumors

Salivary gland tumors (SGTs) consist of a heterogeneous group of lesions accounting for 3% to 10% of all head and neck neoplasms. Little is known about their angiogenic properties, and despite vascular endothelial growth factor (VEGF) has been previously studied in these lesions, further investigations are warranted to better determine its clinical and prognostic significance. In the current study, a total of 132 formalin-fixed, paraffin-embedded SGTs were organized in tissue microarray blocks and submitted to immunohistochemistry against VEGF protein. Slides were scanned and immunoreactions analyzed using Pixelcount V9 algorithm (Aperio Technologies Inc, Vista, CA, USA). Clinical and follow-up data were retrieved from patients' medical charts. Tumors included 50 cases of pleomorphic adenoma, 32 mucoepidermoid carcinomas, 30 adenocarcinomas not otherwise specified, and 20 adenoid cystic carcinomas. A slight male preponderance was found (1.1:1.0), with a mean age of 47.5 years. Parotid gland was the most affected location. Vascular endothelial growth factor expression was found in the cytoplasm of all cases analyzed with variable intensity, proving to be overexpressed in malignant tumors if compared with pleomorphic adenoma. A significant correlation of VEGF reactivity was found only with age, showing no further significant associations. Age and presence of paresthesia were the only features that predicted a lower specific survival rate under univariate and multivariate analyses. Log-rank test evidenced VEGF high expression as a potential determinant of reduced survival, although a statistical significance could not be reached. Hence, considering VEGF overexpression in malignant tumors and its potential association with a lower survival rate, this protein might be associated with SGTs pathogenesis and aggressiveness.

BDNF mediated TrkB activation contributes to the EMT progression and the poor prognosis in human salivary adenoid cystic carcinoma

BACKGROUND

The aim of the present study was to investigate whether the expression of Brain-Derived Neurotrophic Factor (BDNF) and its receptor Tropomyosin-related kinase B (TrkB) is correlated with the clinical progression of salivary adenoid cystic carcinoma (SACC) and whether the BDNF/TrkB axis is associated with the induction of epithelial-mesenchymal transition (EMT) in SACC cells.

METHOD

The expression of BDNF, TrkB, and E-cadherin (an EMT biomarker) in 76 primary SACC specimens and 20 normal salivary gland tissues was analyzed by immunohistochemistry. Additionally, the expression of BDNF, TrkB, and E-cadherin in SACC cell lines (SACC-83 and SACC-LM) was analyzed by RT-PCR and Western blotting. The biological role of the BDNF/TrkB axis in the EMT progression of SACC was evaluated after treatment with increased levels of BDNF and by inhibiting TrkB activity in SACC-83 cell line. The progression of SACC cells through EMT was assessed by RT-PCR, Western blotting, photography, migration and invasion assays.

RESULTS

Elevated expression of TrkB (92.1%) and BDNF (89.5%), and downregulated expression of E-cadherin (47.4%) was found in SACC specimens, which was significantly correlated with the invasion and metastasis in SACC (P<0.05). The high expression of TrkB and the low expression of E-cadherin was significantly correlated with the poor prognosis of SACC patients (P<0.05). The expression of TrkB was inversely correlated with the expression of E-cadherin in both SACC cases and cell lines (P<0.05). Increasing BDNF levels after treatment with exogenous recombinant human BDNF (rhBDNF) at 100 ng/ml significantly promoted the activation of TrKB and the progression of EMT in SACC cells. While obstruction of TrkB by its inhibitor, k252a (100 nM), significantly inhibited the EMT progression of SACC cells.

CONCLUSIONS

These results suggest that BDNF-mediated TrkB activation contributes to the EMT progression and the poor prognosis in SACC. The present study demonstrated that the BDNF/TrkB axis promotes the migration and invasion of SACC cells via EMT in vitro. Targeting the inactivation of the BDNF/TrkB axis may be a potential strategy for the treatment of SACC.

Deregulation of Bmi-1 is associated with enhanced migration, invasion and poor prognosis in salivary adenoid cystic carcinoma

BACKGROUND

Bmi-1 had been found to involve in self renewal of stem cells and tumorigenesis in various malignancies. In this study, we investigated the role of Bmi-1 in the development of salivary adenoid cystic carcinoma (SACC).

METHODS

At first, we confirmed that the deregulation of Bmi-1 was a frequent event in SACC; up-regulation of Bmi-1 was correlated with clinical stages, vital status and distant metastasis and associated with reduced overall survival and disease free survival. SACC-LM cells, higher migration and invasion abilities, elevated the expression of Bmi-1 protein, epithelial-mesenchymal transition (EMT) related proteins (Snail, Slug and Vimentin) and cancer stem cells (CSCs) related proteins (ABCG2, Notch, ALDH-1, Oct-4, Nanog and Epcam) compared to the SACC-83 cells (lower migration and invasion abilities). The migration and invasion abilities were inhibited in SACC-LM cells upon Bmi-1 knockdown. Meanwhile, Bmi-1 knockdown resulted in simultaneous loss of stem cell markers and EMT markers in SACC-LM cells.

CONCLUSION

Our studies confirm that Bmi-1 deregulation plays an important role in the development of SACC and contributes to the migration and the invasion abilities of SACC, which is involved in EMT and CSCs.

GENERAL SIGNIFICANCE

To our knowledge, this is the first study revealing that Bmi-1 deregulation is associated with enhanced migration, invasion and poor prognosis in salivary adenoid cystic carcinoma.

EMMPRIN expression in oral squamous cell carcinomas: correlation with tumor proliferation and patient survival

The aim of our study was to explore the clinicopathological and prognostic significance of extracellular matrix metalloproteinase inducer (EMMPRIN) expression in oral squamous cell carcinomas (OSCC), and its relation with the proliferative tumor status of OSCC. We examined EMMPRIN and Ki-67 proteins expression by immunohistochemistry in 74 cases with OSCC. Statistical analysis was conducted to examine their clinicopathological and prognostic significance in OSCC. EMMPRIN membrane expression was observed in all cases, with both membrane and cytoplasmic tumor expression in 61 cases (82.4%). EMMPRIN overexpression was observed in 56 cases (75.7%). Moderately or poorly differentiated tumors showed EMMPRIN overexpression more frequently than well-differentiated tumors (P = 0.002). Overexpression of EMMPRIN was correlated with high Ki-67 expression (P = 0.004). In the multivariate analysis, EMMPRIN overexpression reveals an adverse independent prognostic value for cancer-specific survival (CSS) (P = 0.034). Our results reveal that EMMPRIN protein is overexpressed in more than two-thirds of OSCC cases, especially in high proliferative and less differentiated tumors. The independent value of EMMPRIN overexpression in CSS suggests that this protein could be used as an important biological prognostic marker for patients with OSCC. Moreover, the high expression of EMMPRIN makes it a possible therapeutic target in OSCC patients.

High expression of SOX2 is associated with poor prognosis in patients with salivary gland adenoid cystic carcinoma

Sex determining region Y-BOX2 (SOX2), one of the key members of the SOX family, is a transcription factor that is involved in the maintenance of embryonic stem cell pluripotency and in multiple developmental processes. Recent studies have shown that SOX2 is aberrantly expressed in several types of tumors. The present study aimed to investigate the clinicopathological and prognostic significance of SOX2 in adenoid cystic carcinoma (ACC) of salivary gland. In this study, the expression of SOX2 in ACC tissues and matched adjacent non-cancerous tissues was measured by immunohistochemistry, western blot, and quantitative polymerase chain reaction. High SOX2 expression occurred in approximately 62.6% of primary ACC. In addition, high expression of SOX2 was significantly associated with T classification (p=0.003) and distant metastasis (p=0.002). The 5-year overall survival (OS) and disease-free survival (DFS) in patients with high SOX2 expression is poorer than those with low SOX2 expression. When adjusted by multivariate analysis, high SOX2 expression, together with distant metastasis, was an independent prognostic factor. The findings of the present study provide evidence that SOX2 represents a potential novel prognostic biomarker for ACC patients.

Synergistic effect of nanosecond pulsed electric field combined with low-dose of pingyangmycin on salivary adenoid cystic carcinoma

Adenoid cystic carcinoma (ACC) is one of the most common malignant neoplasms in salivary glands. To evaluate the therapeutic effects of nanosecond pulsed electric field (nsPEF) combined with pingyangmycin (PYM) on salivary gland adenoid cystic carcinoma (SACC), ACC high metastatic cell line (SACC-LM) and low metastatic cell line (SACC‑83) were tested by CCK-8 assay, cell clonogenic assay, flow cytometry and Transwell assay. Extracellular matrix metalloproteinase inducer (EMMPRIN) expression was tested by western blotting to verify the synergistic mechanism of nsPEF and PYM. The results showed that nsPEF inhibited the cell proliferation of both cell lines, and the inhibitory effect was strongly associated with time and electrical field strength. Moreover, PYM combined with nsPEF may enhance the suppression effect significantly, even at a very low dose (0.01 µg/ml). The synergistic effects may contribute to the downregulation of EMMPRIN expression resulting from the application of nsPEF. For SACC, nsPEF combined with chemotherapy agents may be a valuable strategy not only to improve the treatment effect and prognosis, but also to reduce the side-effects of chemotherapy.

Expression of RECK and MMP-2 in salivary adenoid cystic carcinoma: Correlation with tumor progression and patient prognosis

Reversion-inducing cysteine-rich protein with Kazal motifs (RECK), a glycosylphosphatidylinositol-anchored glycoprotein, inhibits the enzymatic activities of certain matrix metalloproteinases (MMPs). RECK has been studied in numerous human tumors, but the expression of RECK in salivary adenoid cystic carcinoma (SACC), and its correlation with patient prognosis, has never been investigated thus far. In the present study, the expression of RECK and MMP-2 was evaluated in two ACC cell lines and in 83 patients with SACC. The results of quantitative polymerase chain reaction and western blot analysis revealed that the ACC-2 and ACC-M cell lines expressed RECK and MMP-2 mRNA and protein. The immunohistochemical staining in the patients demonstrated that positive expression of RECK and MMP-2 was observed in 21/83 (25.3%) and 69/83 (83.1%) cases, respectively, and that RECK expression was significantly associated with the tumor-node-metastasis stage, histological grade and perineural invasion of patients with SACC (P<0.05). Furthermore, there was a significant association between the positive expression of RECK and that of MMP-2 (P<0.0001). Univariate and multivariate analyses confirmed that a lack of RECK expression was an independent and significant factor for the prediction of a poor prognosis. In conclusion, RECK is a promising prognostic marker and potential therapeutic agent in SACC.

Correlation of β-catenin, but not PIN1 and cyclin D1, overexpression with disease-free and overall survival in patients with cancer of the parotid gland

BACKGROUND

Malignant tumors of the salivary glands comprise about 3% to 5% of all head and neck carcinomas. The purpose of our study was to find possible predictive and/or prognostic markers for parotid cancer.

METHODS

A total of 46 tissue samples of carcinomas of the parotid gland were immunohistochemically stained for ß-catenin, cyclin D1, and PIN1. The factors were analyzed regarding their prognostic value for disease-free and overall survival.

RESULTS

An overexpression of the cytoplasmatic ß-catenin was linked to a statistically significant worse outcome regarding disease-free (p = .0296) and overall survival (p = .0416). The 5-year overall survival was 83.9% in patients without and 0% in patients presenting with overexpression of cytoplasmatic ß-catenin. Additionally, Union Internationale Contre le Cancer (UICC) stage correlated with overall survival (p = .0306) and disease-free survival (DFS; p = .0473).

CONCLUSION

Multivariate analysis showed that overexpression of cytoplasmatic ß-catenin and the UICC stage are 2 independent prognostic markers for survival in patients with parotid cancer.

EMMPRIN co-expressed with matrix metalloproteinases predicts poor prognosis in patients with osteosarcoma

Several studies have focused on the relationships between the expression of extracellular matrix metalloproteinase inducer (EMMPRIN) and the prognosis of patients with malignant tumors. However, few of these have investigated the expression of EMMPRIN in osteosarcoma. We examined expression levels of EMMPRIN immunohistochemically in 53 cases of high-grade osteosarcoma of the extremities and analyzed the correlation of its expression with patient prognosis. The correlation between matrix metalloproteinases (MMPs) and EMMPRIN expression and the prognostic value of co-expression were also analyzed. Staining positivity for EMMPRIN was negative in 7 cases, low in 17, moderate in 19, and strong in 10. The overall and disease-free survivals (OS and DFS) in patients with higher EMMPRIN expression (strong-moderate) were significantly lower than those in the lower (weak-negative) group (0.037 and 0.024, respectively). In multivariate analysis, age (P=0.004), location (P=0.046), and EMMPRIN expression (P=0.038) were significant prognostic factors for overall survival. EMMPRIN expression (P=0.024) was also a significant prognostic factor for disease-free survival. Co-expression analyses of EMMPRIN and MMPs revealed that strong co-expression of EMMPRIN and membrane-type 1 (MT1)-MMP had a poor prognostic value (P=0.056 for DFS, P=0.006 for OS). EMMPRIN expression and co-expression with MMPs well predict the prognosis of patients with extremity osteosarcoma, making EMMPRIN a possible therapeutic target in these patients.

Expression analysis of ovostatin 2 reveals its involvement in proliferation, invasion and angiogenesis of cutaneous malignant melanoma

The relationship of ovostatin 2 (OVOS2) expression with the clinicopathological features of cutaneous malignant melanoma (CMM) was investigated to identify OVOS2 expression in cutaneous melanocytic lesions, and to reveal whether OVOS2 has a function in melanoma progression. Eight specimens of CMM and paracancerous tissue were analyzed using real-time polymerase chain reaction (PCR) and western blot for the mRNA and protein expression of OVOS2, respectively. Immunohistochemical staining was performed on 52 CMM and 62 nevi, followed by clinicopathological significance analysis. The proliferative cells were visualized by staining with Ki-67 antibody. The intensity of angiogenesis was assessed by staining with vascular endothelial growth factor (VEGF). Real-time PCR and western blot analyses showed that OVOS2 was significantly upregulated in cutaneous melanoma than in paired normal skins. Immunohistochemistry showed that 86.5% (45/52) of malignant cases showed OVOS2 cytoplasmic expression compared with 29% (18/62) in benign nevi. OVOS2 expression was significantly higher in invasive and metastatic melanoma than in in situ melanoma (P < 0.01). Furthermore, OVOS2 expression was positively correlated with the known prognostic variables of melanoma including clinical stage, Clark level and Breslow depth. It was also significantly associated with ulcer status, Ki-67 labeling index and VEGF expression in primary melanoma. OVOS2 expression was significantly increased in CMM, which increased incrementally from benign nevi to melanoma and appeared to be involved in the progression of melanoma.

MicroRNA-181a suppresses salivary adenoid cystic carcinoma metastasis by targeting MAPK-Snai2 pathway

BACKGROUND

To date microRNAs and their contribution to the onset and propagation of salivary adenoid cystic carcinoma (SACC) are limited. The objective of this study was to identify miR-181a and its mechanism in the metastasis of SACC.

METHODS

At first microarray and quantitative RT-PCR were used to investigate microRNA profiles and miR-181a in paired SACC cell lines with different metastatic potential. Then the effect of miR-181a on metastatic potential of SACC was investigated. MiR-181a target genes and Snai2 promoter activity were investigated using luciferase reporter gene assays. Western blot was used to detect MAPK-Snai2 pathway-related protein level.

RESULTS

A panel of deregulated microRNAs (including miR-181a) was identified in paired of SACC cell lines. Functional analysis indicated that miR-181a inhibited SACC cell migration, invasion and proliferation in vitro, and it suppressed tumor growth and lung metastasis in vivo. Direct targeting of miR-181a to MAP2K1, MAPK1 and Snai2 was confirmed by luciferase reporter gene assays. MiR-181a mimic inhibited the expression of MAP2K1, MAPK1 and Snai2 in SACC cells. MAP2K1 or MAPK1 siRNA suppressed Snai2 gene promoter activity and reduced Snai2 expression and the metastatic potential of SACC cells.

CONCLUSIONS

Our results indicate that miR-181a plays an important role in the metastasis of SACC, and may serve as a novel therapeutic target for SACC. MiR-181a regulates the MAPK-Snai2 pathway both through direct cis-regulatory mechanism and through indirect trans-regulatory mechanism.

GENERAL SIGNIFICANCE

To our knowledge, this is the first study revealing that miR-181a deregulation mediated the metastasis of SACC by regulating MAPK-Snai2 pathway.

Adenoid cystic carcinoma of the buccal mucosa: A case report and review of the literature

Adenoid cystic carcinomas are deceptive malignancies that show slow growth and local invasion with recurrences seen many years after diagnosis. Upto 50% of these tumors occur in the intraoral minor salivary glands usually in the hard palate. Buccal mucosal tumors are relatively rare. We determined the incidence of buccal mucosal adenoid cystic carcinoma by reviewing the number of reported cases in the literature. This is the first article to analyze the occurrence of adenoid cystic carcinomas in the buccal mucosa through a review of 41 articles. Our review revealed 178 buccal mucosal adenoid cystic carcinomas among a total of 2,280 reported cases. We present a case of adenoid cystic carcinoma occurring in the left buccal mucosa of a 45-year-old female.

Suprabasin is hypomethylated and associated with metastasis in salivary adenoid cystic carcinoma

Background

Salivary gland adenoid cystic carcinoma (ACC) is a rare cancer, accounting for only 1% of all head and neck malignancies. ACC is well known for perineural invasion and distant metastasis, but its underlying molecular mechanisms of carcinogenesis are still unclear.

Principal Findings

Here, we show that a novel oncogenic candidate, suprabasin (SBSN), plays important roles in maintaining the anchorage-independent and anchorage-dependent cell proliferation in ACC by using SBSN shRNA stably transfected ACC cell line clones. SBSN is also important in maintaining the invasive/metastatic capability in ACC by Matrigel invasion assay. More interestingly, SBSN transcription is significantly upregulated by DNA demethylation induced by 5-aza-2′-deoxycytidine plus trichostatin A treatment and the DNA methylation levels of the SBSN CpG island located in the second intron were validated to be significantly hypomethylated in primary ACC samples versus normal salivary gland tissues.

Conclusions/Significance

Taken together, these results support SBSN as novel oncogene candidate in ACC, and the methylation changes could be a promising biomarker for ACC.

Expression of ERBB3 binding protein 1 (EBP1) in salivary adenoid cystic carcinoma and its clinicopathological relevance

Background

ERBB3 binding protein 1 (EBP1) gene transfer into human salivary adenoid cystic carcinoma cells has been shown to significantly inhibit cell proliferation and reduce tumor metastasis in mouse models. In the current study, to evaluate if EBP1 is a novel biomarker capable of identifying patients at higher risk of disease progression and recurrence, we examined the EBP1 expression profile in adenoid cystic carcinoma (ACC) patients and analyzed its clinicopathological relevance. To understand the underlying anti-metastatic mechanism, we investigated if EBP1 regulates invasion-related molecules.

Methods

We performed immunohistochemical analysis on 132 primary adenoid cystic carcinoma and adjacent non-cancerous tissues using commercial EBP1, MMP9, E-cadherin and ICAM-1 antibodies. Results were correlated to clinicopathological parameters, long-term survival and invasion-related molecules by statistical analysis. Cell motility and invasiveness of vector or wild-type EBP1-transfected ACC-M cell lines were evaluated using wound healing and Boyden chamber assays. MMP9, E-cadherin and ICAM-1 proteins in these cell lines were detected using western blot assay.

Results

The expression of EBP1 was significantly higher in non-cancerous adjacent tissues compared with corresponding cancer tissues. The intensity and percentage of cells that reacted with EBP1 antibodies were significantly higher in cases with tubular pattern than those with solid pattern (P<0.0001). We also found adenoid cystic carcinoma with local lymphatic metastasis had significantly lower EBP1 expression than ACC with no local lymphatic node metastasis (P<0.0001). Similar findings were observed in ACC with lung metastasis compared with cases with no lung metastasis (P<0.0001), in particular, in cases with perineural invasion compared with cases with no perineural invasion (P<0.0001). Furthermore, a decrease in EBP1 expression was positively associated with a reduction in overall survival of ACC patients. Of note, EBP1 inhibits migration and invasiveness of ACC cells by upregulating E-cadherin but downregulating MMP9. In clinical adenoid cystic carcinoma patients, higher EBP1 expression was positively correlated with E-cadherin levels (P<0.001) but negatively correlated with MMP9 expression (P=0.0002).

Conclusions

EBP1 expression is reduced in adenoid cystic carcinoma, indicating unfavorable prognosis of ACC patients. Its regulation of MMP9 and E-cadherin protein levels suggests a critical therapeutic potential.

Prognostic value of vascular endothelial growth factor in patients with head and neck cancer: A meta-analysis

BACKGROUND

The correlation between vascular endothelial growth factor (VEGF) overexpression and the clinical outcome of head and neck cancer remains inconclusive. This meta-analysis aimed to evaluate the prognostic value of VEGF in patients with head and neck cancer.

METHODS

We searched Ovid MEDLINE, EMBASE and 2 Chinese science databases in order to enroll all eligible articles. Forty-seven studies were included in this meta-analysis. All results were evaluated by the random-effects model.

RESULTS

VEGF overexpression is significantly associated with worse overall survival (OS; hazard ratio [HR], 1.89; 95% confidence interval [CI], 1.61-2.22) and progression-free survival (PFS; HR, 1.68; 95% CI, 1.33-2.12). Subgroup analysis reveals that VEGF overexpression is a significant poor predictor for nasopharyngeal cancer (HR, 1.66; 95% CI, 1.30-2.12) and salivary gland cancer (HR, 3.32; 95% CI, 1.61-6.84).

CONCLUSION

Our meta-analysis supports that VEGF overexpression is an available poor predictor for patients with head and neck cancer.

Immunoexpression of α2β1, α3β1, and α5β1 integrins in pleomorphic adenoma and adenoid cystic carcinoma

The aim of the present study was to compare the expression of α2β1, α3β1, and α5β1 integrins between 28 pleomorphic adenomas (PAs) and 10 adenoid cystic carcinomas (ACCs), and investigate differences in the expression of these integrins according to histologic subtypes of ACCs. It was taken into consideration the presence or absence, distribution, and localization of integrin immunoexpression. There was immunoreactivity in the intercellular contacts of the strands, nests, and solid sheets of PAs, as well as in the luminal and nonluminal cells of the duct-like structures, with a predominant immunoexpression in the luminal cells. The immunoexpression in ACCs varied with histologic subtype of the tumor. It was verified for a tendency of absence and/or reduced expression of all integrins in the solid subtype of ACCs. In general, PAs revealed a more diffuse and remarkable immunoexpression of all studied integrins than ACCs. The reduced integrins expression in ACC may be related to a lesser degree of cell differentiation in this neoplasm. Moreover, the absence and/or reduced expression of the studied integrins in solid ACC suggest a possible role in pathogenesis and more aggressive biological behavior of this histologic subtype.

Investigation of myoepithelial cell differentiation into Schwann-like cells in salivary adenoid cystic carcinoma associated with perineural invasion

Perineural invasion (PNI) is common in salivary adenoid cystic carcinoma (SACC). The aim of the present study was to explore the association of the Schwann-like cell differentiation with PNI in SACC. Twenty-eight cases of SACC and 10 cases of acinic cell carcinoma (ACA) were examined for the expression of the Schwann cell markers Leu-7 by immunohistochemical staining. The correlation between Leu-7 expression and PNI was analyzed using κ analysis. Immunofluorescence double-staining and pre-embedding immunogold-silver cytochemistry were used to detect the co-expression and the location of Leu-7 and the myoepithelial cell marker α-smooth muscle actin (α-SMA). PNI was identified in 16 SACCs (57.1%) and 1 ACA (10%) and the overexpression of Leu-7 was detected in 22 SACCs (78.6%) and in none of the ACAs (0%). The differences between PNI and Leu-7 expression in SACC and ACA were significant (P<0.05). A correlation was identified between the expression of Leu-7 and PNI in SACC (κ=0.533, P=0.01). In SACC, Leu-7 and α-SMA were co-expressed in the cytoplasm in the same myoepithelial cells. We suggest that Schwann‑like cell differentiation correlates with PNI in SACC and that the differentiation of myoepithelial into Schwann‑like cells may be one of the mechanisms through which PNI occurs in SACC.

Human tumor cells induce angiogenesis through positive feedback between CD147 and insulin-like growth factor-I

Tumor angiogenesis is a complex process based upon a sequence of interactions between tumor cells and endothelial cells. Previous studies have shown that CD147 was correlated with tumor angiogenesis through increasing tumor cell secretion of vascular endothelial growth factor (VEGF) and matrix metalloproteinases (MMPs). In this study, we made a three-dimensional (3D) tumor angiogenesis model using a co-culture system of human hepatocellular carcinoma cells SMMC-7721 and humanumbilical vein endothelial cells (HUVECs) in vitro. We found that CD147-expressing cancer cells could promote HUVECs to form net-like structures resembling the neo-vasculature, whereas the ability of proliferation, migration and tube formation of HUVECs was significantly decreased in tumor conditioned medium (TCM) of SMMC-7721 cells transfected with specific CD147-siRNA. Furthermore, by assaying the change of pro-angiogenic factors in TCM, we found that the inhibition of CD147 expression led to significant decrease of VEGF and insulin-like growth factor-I (IGF-I) secretion. Interestingly, we also found that IGF-I up-regulated the expression of CD147 in both tumor cells and HUVECs. These findings suggest that there is a positive feedback between CD147 and IGF-I at the tumor-endothelial interface and CD147 initiates the formation of an angiogenesis niche.

EMMPRIN contributes to the in vitro invasion of human salivary adenoid cystic carcinoma cells

Extracellular matrix metalloproteinase inducer (EMMPRIN) is a transmembrane glycoprotein that is involved in tumor invasion by stimulating matrix metalloproteinase (MMP) expression. Our previous immunohistochemical study found that the expression of EMMPRIN in salivary adenoid cystic carcinoma (SACC) was positively correlated with tumor perineural and perivascular invasion. The present study was designed to further investigate the role of EMMPRIN in the invasion of SACC. Western blot results showed that EMMPRIN was upregulated in the highly metastatic SACC cell line SACC-LM, compared to SACC-83, a SACC cell line with low metastatic ability. Blocking of EMMPRIN by its antibody significantly decreased the adhesion, secretion of MMP-2 and MMP-9, and invasion activity of SACC-LM cells in vitro (P<0.01). Co-cultures of SACC-LM cells with fibroblasts significantly produced elevated levels of MMP-2 and MMP-9, and promoted the in vitro invasion activity of SACC-LM cells, compared with cultures of SACC-LM cells alone (P<0.01). These results indicate that EMMPRIN may play an important role in the invasion of SACC by stimulating the expression of MMP-2 and MMP-9 in tumor and stromal cells.