Metadherin regulation of vascular endothelial growth factor expression is dependent upon the PI3K/Akt pathway in squamous cell carcinoma of the head and neck.

Our previous study indicated overexpression of metadherin (MTDH) is an adverse prognostic factor in squamous cell carcinoma of the head and neck (SCCHN) and promotes SCCHN cell proliferation and invasion. However, its mechanism remains unclear. Recent studies have indicated that MTDH is a cancer-metastasis-associated molecule that participates in the process of angiogenesis. Therefore, the study is aimed to investigate that whether vascular endothelial growth factor (VEGF), as one of the most potent proangiogenic cytokines, is regulated by MTDH and the role of the phosphatidylinositide 3-kinases/Protein Kinase B (PI3K/Akt) pathway in this process of regulation and the clinical significance of both MTDH and VEGF in SCCHN.Immunohistochemistry was used to assay the expression of MTDH and VEGF in a cohort of 189 SCCHN patients with intact follow-up information. The expression of MTDH was then upregulated or inhibited by lentivirus-mediated MTDH Complementary deoxyribonucleic acid or MTDH short hairpin ribonucleic acid (shRNA) to observe the resulting alterations in VEGF expression and the PI3K/Akt signaling pathway in SCCHN cell lines. In addition, the PI3K/Akt pathway was modulated to observe the resulting changes in the MTDH-mediated expression of VEGF.The immunohistochemistry data showed that MTDH expression is positively correlated with VEGF expression in SCCHN tissues. Moreover, the overexpression of MTDH in SCCHN Tu686 and 5-8F cells led to increases in the expression of VEGF, and this effect was accompanied by activation of the PI3K/Akt pathway. Conversely, shRNA-mediated knockdown of MTDH led to decreased VEGF expression. In addition, inhibition of the Akt signaling pathway reversed the upregulation of VEGF resulting from MTDH overexpression. Moreover, the survival analysis revealed that VEGF is an independent prognostic factor, and a combined survival analysis based on both MTDH and VEGF showed synergistic effects in the prognosis evaluation of SCCHN patients.The findings of the present study demonstrate that MTDH regulates the expression of VEGF via the PI3K/Akt signaling pathway, indicating the potential role of the MTDH-mediated activation of VEGF signaling pathway in SCCHN angiogenesis and metastasis.

[EphA2 mediated vascular endothelial growth factor expression via the p38 MAPK signaling pathway in squamous cell carcinoma of the head and neck].

OBJECTIVE: To investigate the regulatory effect of erythropoietin-producing hepatocellular receptor (EphA2) on the expression of VEGF protein, a pro-angiogenic factor, via p38 mitogen-activated protein kinase (p38 MAPK) signaling pathway in squamous cell carcinoma of the head and neck(SCCHN) in vitro. METHODS: SCCHN Tu686 cells were transfected with EphA2 overexpression vector pEGFP-N1-EphA2. Western blot was used to detect the expression of p38 MAPK and enzyme-linked immunosorbent assay (ELISA) was applied to assay of VEGF. SB203580 as a inhibitor of p38 MAPK signaling pathway was used. RESULTS: The expression of VEGF protein was significantly up-regulated in Tu686 cells transfected with EphA2 overexpression vector (535.31 ± 45.71) pg/ml, when compared with Tu686 cells transfected with empty vector (400.99 ± 33.50) pg/ml and Tu686 cells with no transfection (385.30 ± 33.50) pg/ml (F = 17.091, P < 0.01). The expression of phosphorylated p38 MAPK was obviously increased in Tu686 cells with EphA2 overexpression. SB203580 inhibited the expressions of VEGF and phosphorylated p38 MAPK proteins in Tu686 cells with EphA2 overexpression. CONCLUSION: EphA2 can regulate the expression of VEGF protein and stimulate p38 MAPK signaling pathway.

[Expression of astrocyte elevated gene-1 protein and its clinical significance in laryngeal squamous cell carcinoma].

OBJECTIVE: To assess the protein expression of astrocyte elevated gene-1 (AEG-1) in tissue specimens of laryngeal squamous cell carcinoma (LSCC), and to correlate its expression with clinicopathological parameters and prognosis in patients with LSCC. METHODS: RT-PCR was used to assay the expression of AEG-1 mRNA in 13 pairs of LSCC tissues and their corresponding noncarcinoma epithelia. Immunohistochemistry was performed on paraffin-embedded tissue specimens to investigate the protein expression of AEG-1 in 88 cases of LSCC specimens and 15 cases of adjacent epithelial samples. RESULTS: The expression of AEG-1 mRNA was significantly increased in LSCC tissues compared to adjacent noncarcinoma epithelial tissues (0.81 ± 0.17 vs. 0.23 ± 0.10;t = 10.337, P < 0.001). Meantime, the positive rate of AEG-1 protein in 88 cases of LSCC was 87.5% (77/88). However, 15 cases of adjacent noncarcinoma epithelial merely demonstrated negative or mild expression of AEG-1 protein. AEG-1 overexpression was closely correlated with T stage (χ(2) = 6.289, P = 0.018), clinical stage (χ(2) = 11.049, P < 0.01), metastasis (χ(2) = 20.859, P < 0.01) and recurrence(χ(2) = 13.459, P < 0.01). The overall survival rates of patients with AEG-1 overexpression and low expression were 35.9% and 86.4%, respectively (χ(2) = 23.409, P < 0.01). Multivariate Cox regression analysis revealed that AEG-1 expression was an independent prognostic factor (P = 0.016). CONCLUSION: AEG-1 protein may play a critical role in the initiation and progression of LSCC, implicating its predictive value in prognosis.

[EGCG regulates TGF-ß1-induced epithelial mesenchymal transition in squamous cell carcinoma of head and neck].

OBJECTIVE: To study the effect and molecular mechanism of epigallocatechin-3-gallate (EGCG) on epithelial-mesenchymal transition (EMT) in vitro induced by human recombinant TGF-ß1 protein in squamous cell carcinoma of the head and neck. METHODS: EMT morphological changes of Tu686 cells were observed after sequential treatment of 5 ng/ml TGF-ß1 and 20 µmol/L EGCG. Tu686 cells were collected after the treatment of 5 ng/ml TGF-ß1 for 24 h and EGCG with different concentrations (0, 10, 20, 30 µmol/L) for another 24 h or 20 µmol/L EGCG treatment for different time phase (6, 12, 24 h). Then RT-PCR and Western-blot were applied to detect mRNA and protein expression level of epithelial cell marker E-cadherin, mesenchymal cell marker Vimentin and Smad7, an inhibit molecule of TGF-ß1 mediated pathway in Tu686 cells. RESULTS: TGF-ß1 successfully induced characterized EMT morphological and molecular changes in Tu686 cells, in which expression of E-cadherin decreased, Vimentin increased and Smad7 declined. However, EGCG could reverse the TGF-ß1 mediated process of EMT by downregulating the expression of Vimentin and upregulating the expression of E-cadherin and Smad7. CONCLUSION: EGCG significantly inhibits TGF-ß1-mediated EMT inTu686 cell lines of SCCHN, which maybe associated with the upregulated-expression of Smad7, an inhibitor in TGF-ß1 signaling pathway.

[Expression of HMGB1 protein in laryngeal squamous cell carcinoma and its clinical significance].

OBJECTIVE: To evaluate the expression of HMGB1 protein in tissue specimens of laryngeal squamous cell carcinoma (LSCC) and adjacent normal mucosa, and explore the correlation of HMGB1 protein expression with clinicopathologic features and prognosis in LSCC. METHODS: Ninty-three cases of LSCC and 5 cases of adjcent mucosal tissue samples were included in this study. Immunohistochemical staining was performed on paraffin-embedded tissue specimens to examine the HMGB1 protein expression. The data were futher correlated with the clinicopathological features and prognosis of the LSCC patients. RESULTS: The positive rates of HMGB1 expression in LSCC specimens was 87.1%, significantly higher than that in the adjcent normal mucosa samples (46.7%, P = 0.001), and its overexpresion was closely correlated with T stage (Chi2 = 10.878, P = 0.004), clinical stage (Chi2 = 21.115, P < 0.01), metastasis (Chi2 = 28.298, P < 0.01) and recurrence (Chi2 = 14. 923, P = 0.001) in patients with LSCC. Patients with HMGB1 overexpression had both poorer disease-free survival and poorer overall survival compared with that in patients with low HMGB1 expression (Chi2 = 13.815, Chi2 = 11.912; Both P < 0.01). Univariate and multivariate Cox regression analyses revealed that HMGBI expression is an independent prognostic factor for patients with LSCC. CONCLUSIONS: The results of this study demonstrate that HMGB1 protein expression is significantly increased in LSCC tissues, and HMGB1 protein overexpression is associated with a poorer prognosis in patients with LSCC. These results suggest that HMGB1 may play a critical role in the initiation and progression of LSCC, implicating HMGB1 may become a valuable marker for the prediction of prognosis in patients with LSCC.

[EphA2 promotes angiogenesis and metastasis of head and neck squamous cell carcinoma in vivo].

OBJECTIVE: To investigate the effects of EphA2 on the angiogenesis and cervical lymph node metastasis of squamous cell carcinoma of the head and neck (SCCHN) in vivo. METHODS: EphA2 short hairpin (shRNA) lentiviral particles were used to knockdown the expression of EphA2 in SCCHN cell line M2 with high lymph nodes metastasis rate. Stable clones, obtained by puromycin screening, were assayed by RT-PCR and Western blot to validate the gene silencing efficiency and were used to establish SCCHN metastatic xenograft mouse model. Hematoxylin-eosin staining was applied to identify cervical lymph node metastasis of SCCHN in xenografted tumors. Immunohistochemistry was used to observe microvessel density. Western blot was used to investigate the protein expressions of EphA2 and vascular endothelial, growth factor (VEGF). RESULTS: EphA2 shRNA lentiviral particles efficiently decreased the mRNA and protein expressions of EphA2 in SCCHN cell line M2, which were further successfully utilized to establish SCCHN metastatic xenograft mouse model. Compared with xenografted tumors in control group, xenografted tumors in M2EphA2RNAi(+) group decreased significantly tumor volume [(430.7 ± 190.0) mm(3) (x(-) ± s) vs (1179.0 ± 289.4) mm(3)] and weight [(0.26 ± 0.10) g vs (0.54 ± 0.12) g] (both P < 0.05). More importantly, bilateral cervical lymph node metastasis rate in M2EphA2RNAi(+) was also greatly declined (Mann-Whitney U = 10.0, P < 0.05). Decreased protein expressions of EphA2 and VEGF and microvessel density were observed in M2EphA2RNAi(+) group (t = 26.751, P < 0.01). CONCLUSIONS: Knockdown of EphA2 expression led to the inhibition of tumor growth and metastasis in SCCHN nude mouse model. More importantly, SCCHN angiogenesis was also impeded, which might be associated with the decreased expression of VEGF.

Analysis of transcriptional factors and regulation networks in laryngeal squamous cell carcinoma patients with lymph node metastasis.

The present study was to identify and quantitate differentially expressed proteins in laryngeal squamous cell carcinoma (LSCC) tissues with or without lymph node metastasis and to explore transcriptional factors and regulation networks associated with the process. Tissue specimens were taken from 20 patients with LSCC, including 10 cases of LSCC without metastasis LSCC (N0) and 10 cases of LSCC with metastasis LSCC (Nx). Among the 643 unique proteins identified by using iTRAQ labeling and quantitative proteomic technology, 389 proteins showed an abundance change in LSCC (Nx) as compared to LSCC (N0). Cytoskeleton remodeling, cell adhesion, and immune response activation were found to be the main processes in LSCC metastasis. The construction of transcription regulation networks identified key transcription regulators for lymph node metastasis of LSCC, including Sp1, c-myc, and p53, which may affect LSCC metastasis through the epithelial-mesenchymal transition. Furthermore, our results suggest that ubiquitination may be a critical factor in the networks. The present study provides insights into transcriptional factors and regulation networks involved in LSCC metastasis, which may lead to new strategies for treatment of LSCC metastasis.

[Correlation of EphA2 protein expression with clinicopathological characteristics and prognosis in laryngeal squamous cell carcinoma].

OBJECTIVE: To evaluate the expression of EphA2 protein in tissue specimens and cell lines of laryngeal squamous cell carcinoma (LSCC), and to further study the correlation of EphA2 protein expression with clinicopathological characteristics and prognosis in LSCC. METHODS: Western blot was applied to assess the EphA2 protein expression in LSCC cell line Hep-2 cells and the head and neck immortalized epithelial cell line NP-69 cells. Immunohistochemical staining was performed on paraffin sections of 88 cases of LSCC specimens and 16 cases of adjcent normal tissue samples to investigate the EphA2 protein expression, and to futher elucidate its correlation with clinicopathological characteristics. RESULTS: Compared with the NP-69 cells, EphA2 expression in LSCC cell line Hep-2 cells was upregulated. The positive rates of EphA2 expression in LSCC and adjcent normal tissues samples were 80.7% and 43.8%, respectively, with a significant difference between the two groups (P < 0.001). EphA2 overexpresion was closely correlated with clinical stage (I + II/III + IV, P = 0.005), metastasis (P = 0.025) and recurrence (P = 0.021) in LSCC. Furthermore, patients with EphA2 overexpression had poorer tumor-free survival and 5-year overall survival compared with that in patients with low EphA2 expression (33.3% vs. 63.2%, P = 0.003; 46.7% vs. 81.6%, P = 0.002). EphA2 expression combined with clinical stage provided a better predictive value in prognosis. Univariate and multivariate Cox regression analysis revealed that EphA2 expression is an independent prognostic factor for patients with LSCC (P = 0.019). CONCLUSIONS: The results of this study demonstrate that EphA2 protein expression is significantly increased in LSCC tissues and cell lines, and EphA2 protein overexpression is associated with tumor recurrence, metastasis and poorer prognosis in LSCC patients. These results suggest that EphA2 may play a critical role in the initiation and progression of LSCC, implicating EphA2 as a valuable marker for the prediction of recurrence, metastasis and prognosis in LSCC.

Bone morphogenetic protein-4-induced epithelial-mesenchymal transition and invasiveness through Smad1-mediated signal pathway in squamous cell carcinoma of the head and neck.

BACKGROUND AND AIMS: Bone morphogenetic proteins (BMPs) have recently been shown to be involved in the genesis and progression of a wide variety of carcinomas. The present study was undertaken to estimate the effect of BMP-4 on squamous cell carcinoma of the head and neck (SCCHN) in tissue and cell levels. METHODS: In this study, immunohistochemistry, Western blotting and RT-PCR were utilized to detect the expression of BMP-4, Smad1 and phosphorylated Smad1 in SCCHN tissues or SCCHN cell lines. Those three proteins in tissues were further correlated with prognosis of SCCHN by Kaplan-Meier analysis. The epithelial-mesenchymal transition (EMT)-associated changes in SCCHN cells were detected after stimulation by human BMP-4 recombinant protein and knockdown of Smad1 gene. Meanwhile, the effect on invasiveness and migration was evaluated by invasion and scratch assays, respectively. RESULTS: BMP-4 and p-Smad1 protein were overexpressed in SCCHN tissues with cervical lymph node metastasis, which was significantly higher than those without metastasis. The expression of BMP-4 and p-Smad1 protein was negatively correlated with the prognosis of SCCHN. BMP-4 promoted the invasiveness and migration through EMT, which was demonstrated by morphological alterations, loss of E-cadherin, increase of vimentin and activation of the Smad1 signal pathway. Knockdown of Smad1 expression suppressed BMP-4 induced EMT in both cell lines and weakened the invasiveness and migration of Tu686 and Tu212 in vitro. CONCLUSIONS: Our results demonstrate that BMP-4 protein may contribute to the malignant metastasis of SCCHN, which presents as a novel prognostic marker and a potential therapeutic target for patients with SCCHN.