Salivary Adenoid Cystic Carcinoma Research Articles

Identification of pivotal microRNAs involved in the development and progression of salivary adenoid cystic carcinoma.

miRNAs and mRNAs have been significantly implicated in tumorigenesis and served as promising prognostic biomarkers for human cancer. Hence, this study was aimed to develop the pivotal miRNA biomarkers-based prognostic signature for salivary adenoid cystic carcinoma. The miRNA and mRNA expression data were integrated from the gene expression omnibus database to study their involvement in salivary adenoid cystic carcinoma development and progression. Gene ontology and kyoto encyclopedia of genes and genomes were conducted to analyze the biological pathways. Reverse transcription-quantitative PCR was used to verify the expression of selected miRNAs in salivary adenoid cystic carcinoma and corresponding normal tissues. There were 386 differentially expressed genes: 158 upregulated and 228 downregulated genes and 102 differentially expressed miRNAs: 78 upregulated and 24 downregulated miRNAs in the salivary adenoid cystic carcinoma samples. A miRNA-mRNA network containing 11miRNAs and 199 genes was subsequently constructed. Gene ontology and Kyoto encyclopedia of genes and genomes enrichment analysis revealed that the genes targeted by the 11miRNAs were mostly involved in tumor-related pathways and processes, such as miRNAs in cancer, focal adhesion, neurotrophin signaling pathway, and the PI3K-Akt signaling pathway. Among them, 4miRNAs (miR-375, miR-494, miR-34c-5p, and miR-331-3p) were selected to verify by reverse transcription-quantitative PCR in 36 pairs of collected salivary adenoid cystic carcinoma and adjacent nontumor samples. Overall survival analysis revealed that the higher expression of miR-331-3p was significantly associated with a worst overall survival and multivariate Cox regression analysis suggested that hsa-miR-331-3p could be an independent prognostic factor for salivary adenoid cystic carcinoma. Our results revealed that 4-miRNAs signature was a powerful prognostic biomarker for salivary adenoid cystic carcinoma, which provide a basis for exploring deeper mechanisms regarding the progression of salivary adenoid cystic carcinoma, and leading to the development of potential therapeutic strategies.

Sphk1 promotes salivary adenoid cystic carcinoma progression via PI3K/Akt signaling

The progression of salivary adenoid cystic carcinoma (SACC) is closely related to abnormal gene expression. Herein, the role of Sphk1 in SACC was explored. Sphk1 was overexpressed in SACC tissues. In SACC cell lines, Sphk1 induced cell proliferation, inhibited apoptosis, and promoted cell migration. Moreover, Sphk1 overexpression induced up-regulation of the PI3K protein level and AKT phosphorylation level. Rescue assays further showed that activation of the Sphk1 /PI3K/Akt pathway affected various biological functions of SACC cells. Together, these findings suggested that Sphk1 promotes salivary tumorigenesis by activating the PI3K/ Akt pathway, which may provide novel intervention targets for SACC treatment.

Protein kinase D1 induced epithelial–mesenchymal transition and invasion in salivary adenoid cystic carcinoma via E‐cadherin/Snail regulation

Salivary adenoid cystic carcinoma (SACC) is a malignant tumor, which is characterized by a higher incidence of distant metastasis. The aim of this study was to investigate the role and mechanism of protein kinase D1 (PKD1) in regulating the epithelial-mesenchymal transition (EMT) and promotes the metastasis in SACC. We analyzed the expression of PKD1 in 40 SACC patients and different metastatic potential cell lines. Then, we investigated whether the migration and growth of SACC were regulated by PKD1 using shRNA interference or inhibition of kinase active in vitro cell. Moreover, the mechanism by which PKD1 regulates the stability of Snail protein was determined. Finally, nude mice were used to testify the function of PKD1 via tail vein injection. PKD1 was correlated with metastasis and poor prognosis of SACC patients. PKD1 inhibition attenuated proliferation, migration, invasion, and EMT of SACC cells. Conversely, kinase active PKD1 could induce EMT and promoted cell migration in human HSG cell. Furthermore, downregulation of PKD1 regulated Snail via phosphorylation at Ser-11 on Snail protein and promotion of proteasome-mediated degradation, and reduced lung metastasis in vivo. Our results suggest that PKD1 induces the EMT and promotes the metastasis, which illustrate that PKD1 may be a potential prognostic biomarker and serve as a potential therapeutic target for SACC patients.

Antizyme inhibitor 2 (AZIN2) associates with better prognosis of head and neck minor salivary gland adenoid cystic carcinoma.

The key regulator of the polyamine biosynthetic pathway is ornithine decarboxylase (ODC). ODC is activated by antizyme inhibitor 1 (AZIN1) and 2 (AZIN2). AZIN1 and recently AZIN2 have been related to cancer; however, their functions in adenoid cystic carcinoma (ACC) have not been studied. We performed immunohistochemical study on minor salivary and mucous gland ACC tissue samples of patients treated at the Helsinki University Hospital (Helsinki, Finland) during 1974-2012. We scored AZIN1 and 2 immunoexpression in 42 and 45 tumor tissue samples, respectively, and correlated them with clinicopathological factors and survival. Enhanced AZIN2 expression was associated with better survival. In addition, both AZINs were seen more commonly in cribriform and tubular than in solid growth patterns. AZIN1 expression did not correlate with the studied clinicopathological factors. It seems that AZIN2 expression is higher in cancer tissue with secretory functions. In ACC tissue, high AZIN2 expression could be related to well-differentiated histological type which still has a functioning vesicle transportation system. Thus, AZIN2 could be a prognostic factor for better survival of ACC patients.

CXCL12/CXCR4 facilitates perineural invasion via induction of the Twist/S100A4 axis in salivary adenoid cystic carcinoma.

The activation of CXCL12/CXCR4 axis participated in the progression of multiple cancers, but potential effect in terms of perineural invasion (PNI) in SACC remained ambiguous. In this study, we identified that CXCL12 substantially expressed in nerve cells. CXCR4 strikingly expressed in tumour cells, and CXCR4 expression was closely associated with the level of EMT‐associated proteins and Schwann cell hallmarks at nerve invasion frontier in SACC. Activation of CXCL12/CXCR4 axis could promote PNI and up‐regulate relative genes of EMT and Schwann cell hallmarks both in vitro and in vivo, which could be inhibited by Twist silence. After overexpressing S100A4, the impaired PNI ability of SACC cells induced by Twist knockdown was significantly reversed, and pseudo foot was visualized frequently. Collectively, the results indicated that CXCL12/CXCR4 might promote PNI by provoking the tumour cell to differentiate towards Schwann‐like cell through Twist/S100A4 axis in SACC.

CALCB rs3829222 T/T Genotype and Low Expression of CALCB Are High-Risk Factors for Adenoid Cystic Carcinoma of Salivary Gland.

Objectives To investigate the relationship between polymorphisms of calcitonin-related peptide gene II (beta-calcitonin gene-related peptide (βCGRP), CALCB) and serum CGRP levels in salivary adenoid cystic carcinoma. Materials and Methods Using the polymerase chain reaction (PCR) technique, the full-length amplification and genotype analysis of CALCB genes were performed in 39 patients with adenoid cystic carcinoma of salivary gland and 158 normal controls. The gene frequencies of major genotype of CALCB in adenoid cystic carcinoma of salivary gland and normal control group were analyzed. Enzyme-linked immunosorbent assay (ELISA) was used to evaluate serum calcitonin gene-related peptide (CGRP) and its concentration of alpha and beta subtypes. Results Univariate logistic regression analysis showed that the CALCB rs2839222 T/T genotype was closely related to the occurrence of salivary adenoid cystic carcinoma, with a correlation coefficient of 3.89. Conclusions The serum CGRP concentration in the salivary adenoid cystic carcinoma group was 1.56 times that of the normal control group. The αCGRP subtype was significant, which was 3.02 times that of the normal control. The polymorphism of βCGRP gene is associated with genetic susceptibility to salivary adenoid cystic carcinoma, and serum CGRP and βCGRP can be used as novel markers of salivary adenoid cystic carcinoma.

CXCR5 induces perineural invasion of salivary adenoid cystic carcinoma by inhibiting microRNA-187.

CXCR5 played critical roles in tumorigenesis and metastasis. Nevertheless, little was known about the involvement of CXCR5 in perineural invasion (PNI) of salivary adenoid cystic carcinoma (SACC). Here, we confirmed upregulation of CXCR5 in SACC specimens and cells and identified that CXCR5 exhibited a significant positive correlation with PNI. Functionally, knockdown of CXCR5 suppressed SACC cells migration, invasion and PNI ability, whereas CXCR5 overexpression displayed the opposite effects. Moreover, CXCR5 downregulated microRNA (miR)-187, which could competitively sponge S100A4. The PNI-inhibitory effect of CXCR5 knockdown or miR-187 overexpression could be reversed by elevated expression of S100A4. Conjointly, our data revealed that CXCR5 facilitated PNI through downregulating miR-187 to disinhibit S100A4 expression in SACC.

The expression of the GATA6 gene in oral carcinoma cell lines

BackgroundThis study aimed to investigate the expression level of the GATA6 gene in different oral cancer cells.MethodsIn this study, we sub-cultured normal oral epithelial cell lines HOK, human tongue squamous cell carcinoma cell lines CAL-27 and SCC-4, and human salivary gland adenoid cystic carcinoma cell lines SACC-LM and SACC-83. Subsequently, we used reverse transcription-polymerase chain reaction RT-PCR and Western blot methods to detect the mRNA and the protein expressions of GATA6 in normal oral epithelial cells, human tongue squamous cell carcinoma cells, and human salivary gland adenoid cystic carcinoma cells.ResultsThe results of this study showed that the mRNA expression levels of GATA6 in CAL-27, SCC-4, and SACC-LM cells were significantly increased when compared with the HOK cells. However, the mRNA expression level of GATA6 in the SACC-83 cells had no significant difference compared with the HOK cells. The protein expression levels of GATA6 in the SCC-4 and SACC-LM cells were, however, significantly increased whereas the protein expression levels of GATA6 in the CAL-27 and SACC-83 cells had no significant difference when compared with the HOK cells.ConclusionThe GATA6 gene may be related to the occurrence and progression of certain oral cancers.

Inhibition of DEC2 is necessary for exiting cell dormancy in salivary adenoid cystic carcinoma

BackgroundPatients were prone to have poor prognosis once dormant tumor cells being reactivated. However, the molecular mechanism of tumor cell dormancy remains poorly understood. This study aimed to investigate the function of DEC2 in the dormancy of salivary adenoid cystic carcinoma (SACC) in vitro and vivo.MethodsThe function of DEC2 in tumor dormancy of SACC was investigated in nude mice by establishing primary and lung metastasis model. Meanwhile, the interaction between hypoxia and SACC dormancy and the role of DEC2 were demonstrated through CoCl2 induced hypoxia–mimicking microenvironments. Furthermore, the expression of DEC2 was detected by immunohistochemical staining in primary SACC samples with and without recurrence.ResultsIn the primary SACC, DEC2 overexpression inhibited cell proliferation, increased cell population arrested in G0/G1 phase, and participated in dormancy regulation, which limited tumor growth. Intriguingly, in the model of lung metastasis, the level of DEC2 was reduced significantly and resulted in dormancy exit and growth resumption of SACC cells. Then, we found that DEC2 may associate with hypoxia in contributing to tumor dormancy, which might provide a possible cue to explain the different roles of DEC2 in primary and metastasis lesions. And overexpression of DEC2 induced dormancy and promoted migration and invasion through activating EMT program. Finally, DEC2 positive expression was shown to be significantly correlated with recurrence and dormancy of SACC patients.ConclusionsThese findings provide a novel insight into the role of DEC2 gene in tumor dormancy and metastasis.

The Role of MRPL23 Antisense RNA 1 (MRPL23-AS1) in the Pre-Metastatic Microenvironment of Malignancy During the Process of Epithelial-Mesenchymal Transition

We aimed to explore MRPL23-AS1’s role in the pre-metastatic microenvironment of malignancy during epithelial-mesenchymal transition (EMT). Identification and verification of lncRNA-interacting proteins in salivary adenoid cystic carcinoma (SACC) cells were conducted via RNA-pulldown, silver staining, and Western blotting. RIP and RIP-seq were sequentially administered to verify the binding partners of lncRNA. CHIRP was performed to detect the promoter DNA in the downstream of lncRNA-protein complex. Ultimately CHIP-qPCR detected the effects of lncRNA on the binding degree of its interacting protein to the promoter DNA in the downstream genes and the methyla-tion level of histones in the promoter region. The exosomes secreted by different SACC cells were extracted from culture supernatant to measure lncRNA expression via qPCR. MRPL23-AS1 interacted with EZH2 protein and promoted EZH2 binding to E-cadherin gene promoter region along with the H3K27 methylation. MRPL23-AS1 could promote EMT of SACC cells and increase pulmonary vascular endothelial cells permeability via exosomes secretion. MRPL23-AS1 up-regulated VEGFA, while down-regulated E-cadherin and VE-cadherin in endothelial cells. Exosomes rich in MRPL23-AS1 could boost lung metastasis in vivo. MRPL23-AS1 inhibits E-cadherin level and promotes EMT of SACC cells, suggesting that it might be a biomarker and therapeutic target for lung cancer.

MiR-5191 acts as a tumor suppressor in salivary adenoid cystic carcinoma by targeting Notch-2.

This study sought to investigate the effect of miR-5191 on proliferation, invasion and metastasis in salivary adenoid cystic carcinoma (SACC). The differential expression level of miR-5191 between 5 primary tumor and adjacent non-neoplastic samples, and in two SACC cell lines was detected by quantitative real-time PCR. Cell proliferation, invasion, and migration were performed, followed by luciferase reporter assay and western analysis. The effect of miR-5191 on cell proliferation and apoptosis was evaluated by cell growth and apoptosis assay. The function of miR-5191 in SACC tumorigenesis and metastasis in vivo was investigated by nude mice experiment. The associations between miR-5191/Notch-2 expression and clinicopathological features were analyzed. miR-5191 was downregulated in primary tumor tissues and SACC-LM cells. By targeting Notch-2, miR-5191 expression level affected the migration, invasion, and proliferation of SACC cells. Overexpression of miR-5191 inhibited the expression levels of Notch-2, followed by the decreased expression of c-Myc, Bcl-2, Hes-1, Hey-1, and Cyclin D1. In vivo, miR-5191 overexpression suppressed the SACC tumorigenesis and pulmonary metastasis in mice. In SACC patients, higher expression of miR-5191 was related to better prognoses and lower possibility of metastasis. miR-5191 acts as a tumor suppressor in SACC by targeting Notch-2.

The immunophenotype of epithelial to mesenchymal transition inducing transcription factors in salivary gland adenoid cystic carcinomas.

Adenoid cystic carcinoma (ACC) is the second most common malignant salivary glands neoplasms with a controversial biological behavior. Even though these tumors grow slowly, they have increased potential for recurrence and distant metastasis. In order to elucidate this behavior, our study aimed to investigate the immunoexpression in such tumors of the most important transcriptional factors [Twist, Snail, Slug, and zinc finger E-box binding homeobox 1 (ZEB1)] involved in the epithelial–mesenchymal transition process. The highest level of expression was recorded for Twist, present in all the investigated cases, followed by the Slug and Snail, while no tumor parenchyma reactivity was noticed for the ZEB1 factor. There were tumor reactivity differences regarding topography, histopathological variant, and nerve and lymph node invasion status. Thus, tumors developed from the intraoral minor salivary glands, with solid pattern, perineural invasion, locally aggressive and with lymph node metastasis were the most reactive. Therefore, these transcription factors could be useful as prognostic biomarkers and efficient therapeutic targets in such salivary malignancies.

Bioinformatics identification of the candidate microRNAs and construction of a competing endogenous RNA regulatory network in lacrimal gland adenoid cystic carcinoma high-grade transformation.

Adenoid cystic carcinoma of the lacrimal gland (LACC) is a major orbital malignancy. The recurrence rate and mortality rate are higher in LACC high-grade transformation (LACC-HGT) compared with in LACC. The present study aimed to identify the candidate microRNAs (miRNAs/miRs) and construct a competing endogenous RNA (ceRNA) regulatory network for LACC-HGT. A miRNA microarray on paraffin-embedded tissues was performed to identify the differentially expressed miRNAs (DEMs) of LACC-HGT. The overlap with the salivary adenoid cystic carcinoma miRNA/RNA sequencing dataset in the Gene Expression Omnibus was used to identify candidate miRNAs. In order to construct a ceRNA regulatory network of LACC-HGT, a microarray of mRNA and circRNA in primary cell lines was performed. The circRNAs and genes with high expression in LACC-HGT were predicted as targeting miRNAs, and the circRNA-miRNA-mRNA regulatory network was constructed. miR-140-3p was identified as part of the ceRNA network and as a candidate miRNA, therefore this was further analyzed using reverse transcription-quantitative (RT-q)PCR. Overall, the Agilent Human microarray analysis identified a total of 16 DEMs from the LACC-HGT paraffin-embedded tissues. A total of 653 DECs and 9,566 DEGs of LACC-HGT primary cell lines were screened via the microarray of mRNA and circRNA. The ceRNA regulatory network was constructed using the cross-binding of circRNA-miRNA, miRNA-mRNA and the downregulated miRNAs in LACC-HGT to clearly demonstrate the circRNA-miRNA-mRNA interaction relationship. RT-qPCR results confirmed that miR-140-3p was downregulated in LACC-HGT tissues and primary cell lines compared with LACC. Target genes CD200 and parathyroid hormone-related protein were significantly upregulated in LACC-HGT primary cell lines. miR-140-3p and its target genes may play an important role in LACC-HGT pathogenesis. In conclusion, the current bioinformatics study constructed a ceRNA network based on a microarray, which may help identify novel miRNA therapeutic targets for LACC-HGT.

Newly Identified Members of FGFR1 Splice Variants Engage in Cross-talk with AXL/AKT Axis in Salivary Adenoid Cystic Carcinoma.

Adenoid cystic carcinoma (ACC) is the second most common malignancy of the salivary gland. Although characterized as an indolent tumor, ACC often leads to incurable metastatic disease. Patients with ACC respond poorly to currently available therapeutic drugs and factors contributing to the limited response remain unknown. Determining the role of molecular alterations frequently occurring in ACC may clarify ACC tumorigenesis and advance the development of effective treatment strategies. Applying Splice Expression Variant Analysis and outlier statistics on RNA sequencing of primary ACC tumors and matched normal salivary gland tissues, we identified multiple alternative splicing events (ASE) of genes specific to ACC. In ACC cells and patient-derived xenografts, FGFR1 was a uniquely expressed ASE. Detailed PCR analysis identified three novel, truncated, intracellular domain-lacking FGFR1 variants (FGFR1v). Cloning and expression analysis suggest that the three FGFR1v are cell surface proteins, that expression of FGFR1v augmented pAKT activity, and that cells became more resistant to pharmacologic FGFR1 inhibitor. FGFR1v-induced AKT activation was associated with AXL function, and inhibition of AXL activity in FGFR1v knockdown cells led to enhanced cytotoxicity in ACC. Moreover, cell killing effect was increased by dual inhibition of AXL and FGFR1 in ACC cells. This study demonstrates that these previously undescribed FGFR1v cooperate with AXL and desensitize cells to FGFR1 inhibitor, which supports further investigation into combined FGFR1 and AXL inhibition as an effective ACC therapy.This study identifies several FGFR1 variants that function through the AXL/AKT signaling pathway independent of FGF/FGFR1, desensitizing cells to FGFR1 inhibitor suggestive of a potential resistance mechanism in ACC. SIGNIFICANCE: This study identifies several FGFR1 variants that function through the AXL/AKT signaling pathway independent of FGF/FGFR1, desensitizing cells to FGFR1 inhibitor, suggestive of a potential resistance mechanism in ACC.

Dll4/Notch1 signalling pathway is required in collective invasion of salivary adenoid cystic carcinoma.

High expression of δ-like ligand 4 (Dll4) is reportedly related to the invasion, metastasis, and clinical prognosis of various malignant tumours. Our previous study revealed that collective cell invasion was a common pattern in salivary adenoid cystic carcinoma (SACC). However, the roles of the Dll4/Notch1 signalling pathway in the collective invasion of SACC remain unclear. The present study revealed that Dll4 expression was higher at the invasive front of SACC, and that this upregulation was associated with solid tumour type, high TNM grade, and high rates of metastasis and recurrence. Furthermore, the expression levels of Notch1 and Dll4 were positively correlated at the invasive front, and a three-dimensional (3D) culture model revealed that leader cells showed high expression of Dll4, while follower cells showed high expression of Notch1. Moreover, silencing of Dll4 expression using small interfering RNA reduced the migration, invasion, and collective invasion of SACC cells, and these abilities were rescued by Notch1 overexpression. Finally, SACC collective invasion was increased via the Dll4/Notch1 signalling pathway in experiments that involved a stiff 3D gel, hypoxia and co-culture with human endothelial cells. These findings indicated that the Dll4/Notch1 signalling pathway may be involved in the collective invasion of SACC, which may help to provide possible targets for the treatment of SACC.

Epithelial salivary gland tumors - a monocentric retrospective studyof South Saxony-Anhalt

The purpose of this research was to analyze all epithelial salivary gland tumors in this region in a comprehensive monocentric, retrospective study. In the period from 1993 to 2017, all patients with the diagnosis of epithelial salivary gland tumors either treated at the Department of Oral and Maxillofacial Plastic Surgery of the Martin Luther University, Halle-Wittenberg (MLU), University hospital and/or processed at the Institute of Pathology of the MLU, University hospital and/or registered between 2000 and 2017 by the "Statistisches Landesamt" Sachsen-Anhalt were analyzed. The following parameters were summarized and statistically analyzed in a database using SPSS 21.5: demographic data, tumor localization, entity, therapy and disease course. 382 patients with the diagnosis of epithelial salivary gland neoplasia were identified. With 71 % the most frequent tumor localization was the glandula parotis [n = 271]. 15 % of the tumors originated from minor salivary glands [n = 57]. Most tumors were benign at over 80 % [n = 307]. In Saxony-Anhalt, 5586 patients with epithelial salivary gland tumors were reported in the mentioned period. To the best of our knowledge this is the first epidemiologic analysis of frequency, valency and therapy of salivary gland tumors in Saxony-Anhalt. The results confirm the predominance of benign epithelial salivary gland tumors, most of all pleomorphic adenoma in the glandula parotis. Concerning the group of malignant epithelial salivary gland tumors adenoid cystic carcinoma located in the minor salivary glands were most common.

Expression profile of circular RNA and construction of circular RNA-Micro RNA network in salivary adenoid cystic carcinoma

BackgroundCircular RNAs (circRNAs) is a newly discovered type of non-coding RNA, the abnormal expression of which has been demonstrated in many types of human tumors. So they have been considered as promising candidates as diagnostic and therapeutic targets in cancer. This research aimed to screen the profile of circRNA expression in salivary adenoid cystic carcinoma (SACC).MethodsUsing the threshold of FDR < 0.05 and fold change > 2 or < 0.5, 5 up-regulated and 26 down-regulated circRNAs were identified. The reliability of sequencing was verified by the expression detection of randomly selected circRNAs via qRT-PCR.ResultsMoreover, the circRNA-miRNA system was established by bioinformatics approaches and successfully identified an interaction between circRNA ABCA13 and a cancer-related miRNA (miR-138-5p), which was also verified by qRT-PCR. Moreover, the predicted molecular interaction proved that circRNA ABCA13 may promote SACC through inhibition of miR-138-5p.ConclusionsCollectively, this study has offered the first report about the circRNA expression profile and circRNA-miRNA network in SACC. All of the above could benefit the exploration of novel therapeutic target in SACC treatment.

CASC9 plays a role in salivary adenoid cystic carcinoma in vitro by upregulation of ACLY.

The study was designed to explore the role of cancer susceptibility candidate 9 (CASC9) in salivary adenoid cystic carcinoma (SACC) (SACC-83 and SACC-LM) cell malignant phenotypes. Colony formation assay was used to measure cell proliferation. Transwell assay was used to detect cell migration and invasion. Flow cytometry analysis was applied to determine cell cycle distribution and apoptosis. FISH assay revealed the subcellular location of CASC9. Downregulation of CASC9 inhibited SACC cell proliferation, migration, and invasion, led to cell arrest at G0/G1 phase, and facilitated cell apoptosis. In mechanism, CASC9 bound with microRNA 146b-5p (miR-146b-5p) and negatively modulated miR-146b-5p expression. MiR-146b-5p directly targeted 3' untranslated region of ATP-Citrate Lyase (ACLY) to degrade ACLY in SACC cells. CASC9 upregulated ACLY expression through competitively binding with miR-146b-5p. Furthermore, rescue assays indicated that ACLY overexpression counteracted the effects triggered by CASC9 knockdown on cell proliferation, migration, invasion, and apoptosis in SACC cells. CASC9 facilitated the malignant phenotypes of SACC cells by the regulation of the miR-146b-5p/ACLY axis. These findings might lay foundation for SACC research.

Prognostic biomarkers for salivary adenoid cystic carcinoma: A systematic review

Background: Salivary Adenoid Cystic Carcinoma (ADCC), also known as “Wolf in Sheep's clothing,” is associated with poor prognosis. Regardless of the vigorous treatment, ADCC has been known to recur and metastasize. Hence, identifying informative prognostic biomarkers for Salivary ADCC is of great importance to better predict tumor behavior and to guide treatment planning. Various immunohistochemical biomarkers along with other factors like the histologic grade of the tumor, site of tumor, and age have been studied to establish their correlation with the prognosis of ADCC. Aim: The aim of the systematic review was to identify various markers that have the potential to predict the prognosis in salivary ADCC. Materials and Methods: A literature search was conducted using PubMed and Scopus as database and Google Scholar as an additional source. Studies that performed immunohistochemical analysis predicting the overall survival of patients with salivary ADCC were included in this review. Studies published from 1977 to August 2018 were included. Case reports, review, letter to editors, and articles in languages other than English were excluded from the review. The following outcomes were examined: overall/disease-free survival, metastasis, and recurrence using immunohistochemistry as a prognostic marker. Results: A number of biomarkers were identified by the evaluation of 68 studies, which predicted overall survival and prognosis in terms of recurrence and metastasis. Out of these biomarkers, four markers most frequently assessed markers were Ki-67, p53, vascular endothelial growth factor (VEGF), and cyclin D1, which showed reproducible results. Many other markers showed significant results, but since only a single study was carried out with these markers, it was difficult to assess their predictability. Conclusion: The review thus identified that Ki-67, p53, VEGF could effectively predict metastasis and recurrence in salivary ADCC. More research work is, however, required to validate the accuracy of these markers for their prognostic significance. Many other markers also showed a significant correlation to prognosis; however, multiple studies are required to establish their prognostic value.

Elevated CREPT Expression Enhances the Progression of Salivary Gland Adenoid Cystic Carcinoma

The elevated expression of Cell cycle-Related and Expression-elevated Protein in Tumor (CREPT) is reported to promote the growth of several tumors by enhancing Wnt/β-catenin signaling and cell cycle. However, the relevance of CREPT to the malignancy of salivary gland adenoid cystic carcinoma (SACC) remains unclear. The samples from 51 SACC patients were exploited in this study. We found that SACC samples exhibited a noticeably robuster CREPT expression than the para-cancerous tissues. Statistical analysis suggested that CREPT expression was significantly correlated with the T classification of SACC. To up- or down-regulating CREPT expression, the specific shRNA or full length of CREPT was delivered into SACC cell lines to examine the cell proliferation, migration, colony formation and implanted xenograft survival. Western blot assay and immunohistochemistry were applied to evaluate the expression of CREPT, cyclin D1, c-Myc and CDK4. Up-regulated CREPT in the low metastatic SACC line significantly promoted proliferation and colony formation, as well as cyclin D1, c-Myc and CDK4 expression. While knocking down of CREPT in the high metastatic SACC line remarkably reduced above effects. Furthermore, the SACC xenograft in mice confirmed that down-regulation of CREPT inhibited the in vivo tumor growth. Our study indicated that the elevated CREPT expression promoted the cell proliferation and tumor size of SACC by enhancing the expression of cyclin D1, c-Myc and CDK4, suggesting that CREPT contributed to SACC progression by stimulating cell proliferation, and might act as a potential target in future SACC therapy.