High ACTN1 Is Associated with Poor Prognosis, and ACTN1 Silencing Suppresses Cell Proliferation and Metastasis in Oral Squamous Cell Carcinoma.

PURPOSE: Oral squamous cell carcinoma (OSCC) is a common malignancy of the oral cavity. As the survival rate of OSCC patients is low, it is crucial to explore new markers and therapeutic targets for early diagnosis of the disease. A high level of actinin alpha 1 (ACTN1) in patients could serve as an independent prognostic factor of acute myeloid leukemia. However, the role of ACTN1 in OSCC remains unclear. In the present study, we aimed to investigate the role of ACTN1 in OSCC. METHODS: ACTN1 protein levels in tissues were determined by immunohistochemical (IHC) staining. The correlation of ACTN1 expression with clinicopathological features and prognosis was analyzed. Univariate and multivariate analyses were performed. The effect of ACTN1 knockdown on cell proliferation, migration, invasion, apoptosis, epithelial-mesenchymal transition (EMT), and the cell cycle was evaluated using Western blotting, Cell Counting Kit­8 (CCK8) assays, flow cytometry analysis, transwell assays, wound-healing assays, and nude mouse models of subcutaneous xenograft and pulmonary metastasis. RESULTS: Based on the total score of ACTN1 IHC staining analysis, ACTN1 expression was found to be low in 10 normal mucosal tissues, 48 normal mucosal tissues adjacent to OSCC, and 19 OSCC tissues, but high in 29 OSCC tissues. ACTN1 protein levels were significantly associated with the clinical stage and node metastasis, and a high ACTN1 protein level indicated poor prognosis. Moreover, ACTN1 expression was an independent predictor of poor prognosis of OSCC. Using in vitro assays, we found that ACTN1 knockdown could induce cell cycle arrest, promote apoptosis, and inhibit EMT and cell proliferation, migration, and invasion in the OSCC cell lines, SCC-15 and HSC-3. Moreover, ACTN1 knockdown inhibited subcutaneous tumor growth and pulmonary metastasis in vivo. CONCLUSION: ACTN1 levels were significantly associated with the clinical stage and node metastasis, and a high ACTN1 protein level indicated poor prognosis. Moreover, ACTN1 knockdown could suppress cell proliferation and metastasis of OSCC. Our results suggested that ACTN1 may serve as a diagnostic and prognostic marker of OSCC.

Mesenchymal stem cell-derived CCN2 promotes the proliferation, migration and invasion of human tongue squamous cell carcinoma cells.

Recent studies have demonstrated that mesenchymal stem cells (MSC) exhibit a tropism to tumors and form the tumor stroma. In addition, we found that MSC can secrete different types of factors. However, the involvement of MSC-derived factors in human tongue squamous cell carcinoma (TSCC) growth has not been clearly addressed. The CCN family includes multifunctional signaling molecules that affect the initiation and development events of various tumors. In our study, we report that CCN2/connective tissue growth factor (CTGF) was the most highly induced among the CCN family members in MSC that were co-cultured with TSCC cells. To evaluate the relationship between CCN2 and TSCC growth, we downregulated MSC-derived CCN2 expression with shRNA targeting CCN2 and found that MSC-secreted CCN2 promotes TSCC cell proliferation, migration and invasion. We also confirmed that MSC-derived CCN2 partially accelerated tumor growth in vitro. Taken together, these results suggest that MSC-derived CCN2 contributes to the promotion of proliferation, migration and invasion of TSCC cells and may be a possible therapy target in the future.

Overexpression of HMGA2 promotes tongue cancer metastasis through EMT pathway.

BACKGROUND: Metastasis to long distance organs is the main reason leading to morality of tongue squamous cell carcinoma (TSCC); however, the molecular mechanisms are still unknown. High mobility group AT-hook 2 (HMGA2) is highly expressed in multiple metastatic carcinomas, in which it contributes to cancer progression, metastasis and poor prognosis by upregulating Snail expression and inducing epithelial mesenchymal transition (EMT). This study focuses on investigating the role and mechanism of regulation of HMGA2 in the metastasis of TSCC. METHODS: HMGA2 mRNA and protein expression were examined in TSCC specimens by quantitative real-time polymerase chain reaction, western blotting and immunohistochemistry (IHC). Western blotting, IHC and immunofluorescence were also used to measure the expression and localization of EMT marker E-Cadherin and Vimentin both in TSCC cells and tissues. Knockdown assay was performed in vitro in TSCC cell lines using small interfering RNAs and the functional assay was carried out to determine the role of HMGA2 in TSCC cell migration and invasion. RESULTS: TSCC mRNA and protein expression were significantly up-regulated in tumor tissues when compared to adjacent non-tumor tissues, and the overexpression of HMGA2 was closely correlated with lymph nodes metastasis. Clinicopathological analysis indicated that HMGA2 expression was associated with clinical stage (P = 0.001), lymph node metastasis (P = 0.000), histological differentiation (P = 0.002) and survival (P = 0.000). Silencing the HMGA2 expression in Cal27 and UM1 resulted in the inhibition of cell migration and invasion, meanwhile down-regulation of HMGA2 impaired the phenotype of EMT in TSCC cell lines and tissues. The Multivariate survival analysis indicates that HMGA2 can be an independent prognosis biomarker in TSCC. CONCLUSION: Our findings demonstrate that HMGA2 promotes TSCC invasion and metastasis; additionally, HMGA2 is an independent prognostic factor which implied that HMGA2 can be a biomarker both for prognosis and therapeutic target of TSCC.