Zhao-yu Lin

MiR-21 Indicates Poor Prognosis in Tongue Squamous Cell Carcinomas as an Apoptosis Inhibitor

Purpose: We aim to examine miR-21 expression in tongue squamous cell carcinomas (TSCC) and correlate it with patient clinical status, and to investigate its contribution to TSCC cell growth, apoptosis, and tumorigenesis. Experimental Design: MicroRNA profiling was done in 10 cases of TSCC with microarray. MiR-21 overexpression was quantitated with quantitative reverse transcription-PCR in 103 patients, and correlated to the pathoclinical status of the patients. Immunohistochemistry was used to examine the expression of TPM1 and PTEN, and terminal deoxynucleotidyl transferase–mediated dUTP labeling to evaluate apoptosis. Moreover, miR-21 antisense oligonucleotide (ASO) was transfected in SCC-15 and CAL27 cell lines, and tumor cell growth was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, adherent colony formation, and soft agar assay, whereas apoptosis was determined by Annexin V assay, cytochrome c release, and caspase 3 assay. Tumorigenesis was evaluated by xenografting SCC-15 cells in nude mice. Results: MiR-21 is overexpressed in TSCC relative to adjacent normal tissues. The level of miR-21 is reversely correlated with TPM1 and PTEN expression and apoptosis of cancer cells. Multivariate analysis showed that miR-21 expression is an independent prognostic factor indicating poor survival. Inhibiting miR-21 with ASO in TSCC cell lines reduces survival and anchorage-independent growth, and induces apoptosis in TSCC cell lines. Simultaneous silencing of TPM1 with siRNA only partially recapitulates the effect of miR-21 ASO. Furthermore, repeated injection of miR-21 ASO suppresses tumor formation in nude mice by reducing cell proliferation and inducing apoptosis. Conclusions: miR-21 is an independent prognostic indicator for TSCC, and may play a role in TSCC development by inhibiting cancer cell apoptosis partly via TPM1 silencing.

MiR-200b and miR-15b regulate chemotherapy-induced epithelial-mesenchymal transition in human tongue cancer cells by targeting BMI1

Chemotherapy has been reported to induce epithelial-mesenchymal transition (EMT) in tumor cells, which is a critical step in the process of metastasis leading to cancer spreading and treatment failure. However, the underlying mechanisms of chemotherapy-induced EMT remain unclear, and the involvement of microRNAs (miRNA) in this process is poorly understood. To address these questions, we established stable chemotherapy-resistant tongue squamous cell carcinoma (TSCC) cell lines CAL27-res and SCC25-res by exposing the parental CAL27 and SCC25 lines to escalating concentrations of cisplatin for 6 months. CAL27-res and SCC25-res cells displayed mesenchymal features with enhanced invasiveness and motility. MiRNA microarray illustrated that miR-200b and miR-15b were the most significantly downregulated microRNAs in CAL27-res cells. Ectopic expression of miR-200b and miR-15b with miRNA mimics effectively reversed the phenotype of EMT in CAL27-res and SCC25-res cells, and sensitized them to chemotherapy, but inhibition of miR-200b and miR-15b in the sensitive lines with anti-sense oligonucleotides induced EMT and conferred chemoresistance. Retrieving the expression of B lymphoma Mo-MLV insertion region 1 homolog (BMI1), a target for miR-200b and miR-15b, in the presence of the miRNA mimics by transfecting CAL27-res cells with pcDNA3.1–BMI1-carrying mutated seed sequences of miR-200b or miR-15b at its 3′-UTR recapitulated chemotherapy-induced EMT. In vivo, enforced miR-200b or miR-15b expression suppressed metastasis of TSCC xenografts established by CAL27-res cells. Clinically, reduced miR-200b or miR-15b expression was associated with chemotherapeutic resistance in TSCCs and poor patient survival. Our data suggest that reduced expression of miR-200b and miR-15b underscores the mechanisms of chemotherapy-induced EMT in TSCC, and may serve as therapeutic targets to reverse chemotherapy resistance in tongue cancers.

miR‐639 regulates transforming growth factor beta‐induced epithelial–mesenchymal transition in human tongue cancer cells by targeting FOXC1

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.

MiR-320a acts as a prognostic factor and Inhibits metastasis of salivary adenoid cystic carcinoma by targeting ITGB3

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.

miR-483-5p determines mitochondrial fission and cisplatin sensitivity in tongue squamous cell carcinoma by targeting FIS1

Mitochondria play an important role in the initiation of apoptosis. However, whether cisplatin can induce apoptosis by initiating a mitochondrial fission pathway and the mechanism underlying this effect remain poorly understood. In this study, we show that the mitochondrial fission protein FIS1 is upregulated upon cisplatin treatment in tongue squamous cell carcinoma (TSCC) cells. FIS1 knockdown can attenuate mitochondrial fission and cisplatin sensitivity. We found that FIS1 is a direct target of miR-483-5p and that miR-483-5p can inhibit mitochondrial fission and cisplatin sensitivity in vitro and in vivo. Furthermore, we found that miR-483-5p and FIS1 are significantly associated with cisplatin sensitivity and with overall survival in patients with TSCC in a retrospective analysis of multiple centers. This study revealed that a novel mitochondrial fission pathway composed of miR-483-5p and FIS1 regulates cisplatin sensitivity. The modulation of miR-483-5p and FIS1 levels may provide a new approach for increasing cisplatin sensitivity.

A role for cancer-associated fibroblasts in inducing the epithelial-to-mesenchymal transition in human tongue squamous cell carcinoma

OBJECTIVES Lymph node metastasis is a prominent clinical feature of tongue squamous cell carcinoma (TSCC) and is associated with a higher mortality rate. Carcinoma-associated fibroblasts (CAFs), a major component of the tumor microenvironment (TME), play an important role in tumor progression, and are associated with a poor prognosis. The aim of this study was to examine the role of CAFs in promoting the invasion of TSCC through the epithelial-to-mesenchymal transition (EMT). MATERIALS AND METHODS A series of matched CAF and normal fibroblast (NF) pairs were assessed for cell morphology and for the expression of alpha smooth muscle actin (α-SMA), stromal cell-derived factor-1 (SDF1), fibroblast-activating protein (FAP), vimentin, and cytokeratin (CK) markers. Transwell assays, Western blot analysis, reverse transcription-PCR, and immunofluorescence staining were used to assess the role of CAFs, as compared to that of NFs, in promoting proliferation, migration, invasion, and EMT in TSCC. RESULTS Both CAF and NF primary cultures expressed vimentin but not CK. CAFs showed significantly higher α-SMA protein levels, SDF1 secretion, and mRNA levels of α-SMA, SDF1, and FAP. We also found that co-culture with CAFs enhanced the proliferation and invasion of SCC9 cells. Moreover, co-culture with CAFs induced upregulation of the EMT markers fibronectin and vimentin, downregulation of E-cadherin, and enhanced invasion in SCC9 cells. CONCLUSION These results suggest that CAFs induce EMT marker expression and functional changes in TSCCs.

Prognostic significance of erythropoietin and erythropoietin receptor in tongue squamous cell carcinoma

Despite its primary hematopoietic function, erythropoietin (Epo) is a pleiotropic cytokine that exerts various biological functions in many different non-hematopoietic cells and cancers, and its stimulatory effects are mediated through activation of its receptor (EpoR). Recent studies have shown that Epo and EpoR may be involved in carcinogenesis, angiogenesis, and invasion. We have investigated the expression of Epo and EpoR in a series of 65 resected squamous cell carcinomas (SCC) of the tongue using immunohistochemical staining. The proportion of Epo and EpoR changes in them was greater than those in normal squamous epithelium (P<0.05). Epo expression was associated with age, density of microvessels, and the stage of the tumour (P<0.05). EpoR expression was associated with microvascular density alone (P<0.05). After adjusting for other clinicopathological factors, Epo and EpoR expression remained independent adverse prognosticators for postoperative survival (P<0.05). Our findings support the hypothesis that the Epo and EpoR systems influence the prognosis of carcinogenesis, angiogenesis, and malignant progression of SCC of the tongue, and confirm that Epo and EpoR are independent prognostic markers.

Tumor necrosis factor α induces myofibroblast differentiation in human tongue cancer and promotes invasiveness and angiogenesis via secretion of stromal cell-derived factor-1.

OBJECTIVES Cancer-associated fibroblasts (CAFs) play an important role in tumor progression and are associated with a poor prognosis. Tumor necrosis factor α (TNFα) has been involved in growth and metastasis associated with epithelial-mesenchymal transition (EMT) in many types of cancers. However, the relationship among the TNFα, activation of CAFs and their tumor-promoting effects on tongue squamous cell carcinoma (TSCC) remain obscure. MATERIALS AND METHODS A series of matched primary CAFs and normal fibroblasts (NFs) pairs were cultured, and additionally two TSCC cell lines SCC9 and CAL27, were treated with TNFα or CAFs derived stromal cell-derived factor-1 (SDF1) respectively to study invasion and EMT in vitro. In addition, NFs were treated with TNFα to detect the expression of myofibroblast markers, invasion, induced collagen gel contraction and enhanced cancer metastasis. Finally, invasion and angiogenesis of human vein endothelial cells (HUVECs) treated with TNFα and CAFs derived SDF1 was measured. RESULTS TNFα and CAFs-derived SDF1 induced TSCC cells metastasis and EMT separately. TNFα facilitated the transformation of NFs to CAFs-like fibroblasts, which was accompanied by acquisition of similar myofibroblast markers expression and malignant function to CAFs. Furthermore, TNFα and CAFs derived SDF1 also promoted invasion and angiogenesis of HUVECs. CONCLUSION These results suggest that TNFα may not only directly but also indirectly enhance cancer metastasis, EMT and angiogenesis formation in tongue cancer through myofibroblast differentiation via SDF1 secretion.

Extracellular matrix metalloproteinase inducer expression in salivary gland tumors: a correlation with microvessel density.

The purpose of this study was to investigate the expression pattern of extracellular matrix metalloproteinase inducer (EMMPRIN) as well as the correlation between EMMPRIN and microvessel density (MVD) in salivary gland tumors. Extracellular matrix metalloproteinase inducer expression and MVD were examined immunohistochemically on paraffin-embedded tissue specimens from 95 patients with salivary gland tumors, who underwent surgical resection from 1998 to 2006. Reverse transcription-polymerase chain reaction was used to monitor EMMPRIN mRNA expression in frozen samples. Extracellular matrix metalloproteinase inducer expression in mucoepidermoid carcinomas and adenoid cystic carcinomas was significantly higher than in normal salivary gland tissues and pleomorphic adenomas(P < 0.05). The MVD of mucoepidermoid carcinomas and adenoid cystic carcinomas was significantly higher compared with pleomorphic adenomas(P < 0.05). The MVD of the EMMPRIN-positive expression group was significantly higher than the MVD of the EMMPRIN-negative expression group(P < 0.05). Extracellular matrix metalloproteinase inducer mRNA expression in malignant salivary gland tumors was higher than that in pleomorphic adenomas(P < 0.05). This study suggests that EMMPRIN expression is an important feature of malignant salivary gland tumors and can be used as a biologic marker to characterize salivary gland tumors. Extracellular matrix metalloproteinase inducer is also a positive angiogenic factor in salivary gland tumors.

Extended vertical lower trapezius island myocutaneous flap versus pectoralis major myocutaneous flap for reconstruction in recurrent oral and oropharyngeal cancer

The purpose of this study was to compare the use of an extended vertical lower trapezius island myocutaneous flap (TIMF) and a pectoralis major myocutaneous flap (PMMF).