Numerous findings have demonstrated that long noncoding RNA (lncRNA) dysregulation plays a key role in many human neoplasms, including tongue squamous cell carcinoma (TSCC), yet the potential mechanisms of lncRNAs in chemo-resistance remain elusive. Our research showed that the lncRNA KCNQ1OT1 was upregulated in chemo-insensitive TSCC tissues compared with chemo-sensitive TSCC specimens. Meanwhile, high KCNQ1OT1 expression was closely correlated with poor prognosis. Furthermore, KCNQ1OT1 promoted TSCC proliferation and conferred TSCC resistance to cisplatin-induced apoptosis in vitro and in vivo. Using online database analysis, we predicted that the lncRNA KCNQ1OT1 facilitates tumor growth and chemo-resistance by acting as a competing endogenous RNA (ceRNA) to modulate the expression of miR-211-5p. And miR-211-5p upregulation significantly impaired TSCC proliferation and resumed TSCC chemo-sensitivity, which is contrary to the function of lncRNA KCNQ1OT1. Luciferase experiments confirmed that miR-211-5p harbor binding sites for the 3′-UTRof Ezrin mRNA, and Ezrin/Fak/Src signaling was activated in cisplatin-resistant TSCC cells. Finally, miR-211-5p inhibition in sh-KCNQ1OT1-expressing TSCC cells rescued the suppressed cell proliferation and cisplatin resistance induced by KCNQ1OT1 knockdown. In summary, our study has elucidated the role of the oncogenic lncRNA KCNQ1OT1 in TSCC growth and chemo-resistance, which may serve as a new target for TSCC therapy.

Oral squamous cell carcinoma (OSCC) has a high incidence of cervical micrometastases and sometimes metastasizes contralaterally because of the rich lymphatic intercommunications relative to submucosal plexus of oral cavity that freely communicate across the midline, and it can facilitate the spread of neoplastic cells to any area of the neck consequently. Clinical and histopathologic factors continue to provide predictive information to contralateral neck metastases (CLNM) in OSCC, which determine prophylactic and adjuvant treatments for an individual patient. This review describes the predictive value of clinical-histopathologic factors, which relate to primary tumor and cervical lymph nodes, and surgical dissection and adjuvant treatments. In addition, the indications for elective contralateral neck dissection and adjuvant radiotherapy (aRT) and strategies for follow-up are offered, which is strongly focused by clinicians to prevent later CLNM and poor prognosis subsequently.

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BackgroundSalivary Adenoid cystic carcinoma (SACC) patients with local invasion and lung metastasis are often resistant to conventional therapy such as operation, chemotherapy and radiotherapy. To explore the underling mechanisms, we studied the roles of miRNA in regulating invasiveness of SACC cells.MethodsMicroRNA profiling was done in SACC cells with microarray. MiRNA mimics or antisense oligonucleotide was transfected and invasiveness of SACC cells was evaluated by adhesion assay and transwell assay. The target gene of miRNA was identified by luciferase reporter assay and “rescue” experiment. Tumor metastasis was evaluated by BALB/c-nu mice xenografts. MiRNA and its target gene expression were identified by in-situ hybridization and immunohistochemistry respectively, in 302 patients from affiliated hospitals of Sun Yat-sen University and in 148 patients from affiliated hospitals of Central South University, and correlated to the clinicopathological status of the patients.ResultsMiR-320a was down-regulated in high lung metastatic ACCM and SACC-LM cells compared with the corresponding low metastatic ACC2 and SACC-83 cells, and inhibited adhesion, invasion and migration of SACC cells by targeting integrin beta 3 (ITGB3). In vivo, enforced miR-320a expression suppressed metastasis of SACC xenografts. In the two independent sets, miR-320a was downregulated in primary SACCs with metastasis compared to those without metastasis, and low expression of this miRNA predicts poor patient survival and rapid metastasis. Multivariate analysis showed that miR-320a expression was an independent indicator of lung metastasis.ConclusionsMiR-320a inhibits metastasis in SACCs by targeting ITGB3 and may serve as a therapeutic target and prognostic marker in salivary cancers.Electronic supplementary materialThe online version of this article (doi:10.1186/s12943-015-0344-y) contains supplementary material, which is available to authorized users.

Epithelial-to-mesenchymal transition (EMT) is implicated in embryonic development and various pathological events. Transforming growth factor beta (TGFβ) has been reported to induce EMT in tumor cells, which is a critical step in the process of metastasis leading to cancer spreading and treatment failure. However, the involvement of microRNA during the EMT process in tongue squamous cell carcinoma (TSCC) remains to be determined. To address this question, TSCC cell lines SCC9 and CAL27 were treated with human recombinant TGFβ1 for 48 h. miRNA microarray illustrated that miR-639 was significantly downregulated in TGFβ-treated SCC9 cells. Ectopic expression of miR-639 with miRNA mimics effectively blocked TGFβ-induced EMT in SCC9 and CAL27 cells, but inhibition of miR-639 in SCC9 and CAL27 cells with antisense oligonucleotides induced EMT. Computational microRNA target predictions detected a conserved sequence matching to the seed region of miR-639 in the 3′-UTR of FOXC1 mRNA. Luciferase reporter assays revealed that miR-639 targets FOXC1. Ectopic expression of FOXC1 induces EMT in TSCC cells. Silencing FOXC1 expression blocked TGFβ-induced EMT in SCC9 cells. Clinically, reduced miR-639 expression was associated with metastasis in TSCC and poor patient survival. The data from the present study suggest that reduced expression of miR-639 underscores the mechanism of TGFβ-induced EMT in TSCC by targeting FOXC1 and may serve as therapeutic targets in the process of metastasis.

These results suggest that CAFs induce EMT marker expression and functional changes in TSCCs.

Cisplatin has been widely employed as a cornerstone chemotherapy treatment for a wide spectrum of solid neoplasms; increasing tumor responsiveness to cisplatin has been a topic of interest for the past 30 years. Strong evidence has indicated that mitochondrial fission participates in the regulation of apoptosis in many diseases; however, whether mitochondrial fission regulates cisplatin sensitivity remains poorly understood. Here, we show that MFF mediated mitochondrial fission and apoptosis in tongue squamous cell carcinoma (TSCC) cells after cisplatin treatment and that miR-593-5p was downregulated in this process. miR-593-5p attenuated mitochondrial fission and cisplatin sensitivity by targeting the 3′ untranslated region sequence of MFF and inhibiting its translation. In exploring the underlying mechanism of miR-593-5p downregulation, we observed that BRCA1 transactivated miR-593-5p expression and attenuated cisplatin sensitivity in vitro. The BRCA1-miR-593-5p-MFF axis also affected cisplatin sensitivity in vivo. Importantly, in a retrospective analysis of multiple centers, we further found that the BRCA1-miR-593-5p-MFF axis was significantly associated with cisplatin sensitivity and the survival of patients with TSCC. Together, our data reveal a model for mitochondrial fission regulation at the transcriptional and post-transcriptional levels; we also reveal a new pathway for BRCA1 in determining cisplatin sensitivity through the mitochondrial fission program.

miR-582-5p could suppress effect on the process of invasion and migration in SACC cell lines, and this could occur through its target gene FOXC1.