Abstract

Ronghai Zou¹,

Zhenggang Chen^2,3,†,

Bing Fan¹,

Zhaoyan Wang⁴,

Ying Wang⁵,

Xiaonan Yin³,

Dong Zhang^6,7,

Lei Tong³,

Fang Yang³,

Weina Jiang⁸,

Wensheng Fu⁹,

Jiwei Zheng^10,11,†,

Martin O. Bergo¹²,

Martin Dalin¹²,

Jiawei Zheng^2,*,

Shulan Chen³ and

Jianhua Zhou³

²Department of Oral and Maxillofacial Surgery, Ninth People’s Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, China

³Department of Stomatology, Qingdao Municipal Hospital, Qingdao University, Qingdao 266071, China

⁴Department of Clinical Laboratory, Qingdao Municipal Hospital, Qingdao University, Qingdao 266071, China

⁵Department of Pediatrics, Qingdao Municipal Hospital, Qingdao University, Qingdao 266071, China

⁶Department of Oral Maxillofacial Surgery, Qilu Hospital, Shandong University, Jinan 250012, China

⁷Department of Cancer, Stomatology Research Center, Shandong University, Jinan 250012, China

⁸Department of Pathology, Qingdao Municipal Hospital, Qingdao University, Qingdao 266071, China

⁹Department of Oncology, Qingdao Hiser Medical Group, Qingdao 266033, China

¹⁰School of Stomatology, Xuzhou Medical College, Jiangsu 221004, China

¹¹Department of Stomatology, Affiliated Hospital of Xuzhou Medical College, Jiangsu 221004, China

¹²Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Cancer Center, Gothenburg University, Gothenburg S-413 90, Sweden

^† These authors contributed equally to this work.

Abstract  Ras homolog gene family member A (RhoA) has been identified as a critical regulator of tumor aggressive behavior. In this study, we assessed the role of RhoA in the mechanisms underlying growth, migration, and invasion of squamous cell carcinoma of tongue (TSCC). Stable RhoA knockdown of TSCC cell lines SCC-4 and CAL27 were achieved using Lentiviral transfection. The effects of RhoA depletion on cell migration, invasion, and cell proliferation were determined. The possible underlying mechanism of RhoA depletion on TSCC cell line was also evaluated by determining the expression of Galectin-3 (Gal-3), β-catenin, and matrix metalloproteinase-9 (MMP-9) in vivo. Meanwhile, the underlying mechanism of TSCC growth was studied by analysis of cyclin D1/2, p21CIP1/WAF1, and p27Kip1 protein levels. Immunohistochemical assessments were performed to further prove the alteration of Gal-3 and β-catenin expression. We found that, in mice injected with human TSCC cells in the tongue, RhoA levels were higher in primary tumors and metastasized lymph nodes compared with those in the normal tissues. Silencing of RhoA significantly reduced the tumor growth, decreased the levels of Gal-3, β-catenin, MMP-9, and cyclin D1/2, and increased the levels of p21CIP1/WAF1 and p27Kip1. In vitro, RhoA knockdown also led to inhibition of cell migration, invasion, and proliferation. Our data suggest that RhoA plays a significant role in TSCC progression by regulating cell migration and invasion through Wnt/β-catenin signaling pathway and cell proliferation through cell cycle regulation, respectively. RhoA might be a novel therapeutic target of TSCC.

Keywords   RhoA; tumor invasion; metastasis; tumor growth; Wnt/β-catenin signaling pathway

Received   2014-1-6　　

Accepted  2014-4-18

Funding  This work was supported by the grants from the National Natural Science Foundation of China (81372908), Doctoral Science Grant of China (2013M541530), Qingdao Municipal Science & Technology Commission (2012-1-3-1-(16)-nsh), and Jiangsu College Natural Sci

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