title: SPAG9 is involved in hepatocarcinoma cell migration and invasion via modulation of ELK1 expression.
abstract: BACKGROUND
  Sperm-associated antigen 9 (SPAG9) is upregulated in several malignancies and its overexpression is positively correlated with cancer cell malignancies. However, the specific biological roles of SPAG9 in hepatocellular carcinoma (HCC) are less understood.
  
  
  METHODS
  We analyzed SPAG9 and ETS-like gene 1, tyrosine kinase (ELK1) expression in 50 paired HCC specimens and adjacent noncancerous liver specimens using immunohistochemistry. SPAG9 small interfering RNA (siRNA) was used to knockdown SPAG9 expression in HCCLM3 and HuH7 cell lines. We used plasmids to upregulate ELK1 expression and siRNA to downregulate ELK1 expression in HuH7 cells. Quantitative real-time polymerase chain reaction and Western blot were used to evaluate the expression of SPAG9 and ELK1 at the mRNA and protein level, respectively. Wound healing, matrigel migration, and invasion analyses were performed to determine the effect of SPAG9 and ELK1 on HCC metastasis.
  
  
  RESULTS
  SPAG9 and ELK1 were overexpressed in HCC tissue specimens and their expressions were higher in HCCLM3 and HuH7 cells compared to the low-metastatic HepG2 cells. Overexpression of SPAG9 was positively associated with tumor-node-metastasis staging (P=0.032), metastasis parameters (P=0.018) of HCC patients, and ELK1 expression (r=0.422, P<0.001) in HCC tissue specimens. In addition, knockdown of SPAG9 in HCCLM3 and HuH7 cells using siRNA significantly suppressed cell migration and invasion. Furthermore, we observed inhibition of ELK1 expression and p38 signaling. However, ELK1 overexpression reversed the inhibitory effects of SPAG9 siRNA on HCC cell metastasis and ELK1 depletion inhibited HuH7 cell migration and invasion.
  
  
  CONCLUSIONS
  SPAG9 overexpression was positively correlated with HCC metastasis and SPAG9-induced migration and invasion were partially dependent on ELK1 expression in HCC cell lines. These results suggest that SPAG9 may be a potential anti-metastasis target effective in HCC therapy.
authors.affiliation: Shaoxing People's Hospital, Shaoxing Hospital Zhejiang University, Shaoxing, Zhejiang, People's Republic of China; The Key Laboratory of Laboratory Medicine, Ministry of Education of China, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, People's Republic of China.
authors.forename: Qiuyue
authors.initials: Q
authors.lastname: Yan
authors.affiliation: State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, People's Republic of China.
authors.forename: Guohua
authors.initials: G
authors.lastname: Lou
authors.affiliation: Shaoxing People's Hospital, Shaoxing Hospital Zhejiang University, Shaoxing, Zhejiang, People's Republic of China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Qian
authors.affiliation: Shaoxing People's Hospital, Shaoxing Hospital Zhejiang University, Shaoxing, Zhejiang, People's Republic of China.
authors.forename: Bo
authors.initials: B
authors.lastname: Qin
authors.affiliation: Shaoxing People's Hospital, Shaoxing Hospital Zhejiang University, Shaoxing, Zhejiang, People's Republic of China; The Key Laboratory of Laboratory Medicine, Ministry of Education of China, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, People's Republic of China.
authors.forename: Xiuping
authors.initials: X
authors.lastname: Xu
authors.affiliation: Shaoxing People's Hospital, Shaoxing Hospital Zhejiang University, Shaoxing, Zhejiang, People's Republic of China; The Key Laboratory of Laboratory Medicine, Ministry of Education of China, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, People's Republic of China.
authors.forename: Yanan
authors.initials: Y
authors.lastname: Wang
authors.affiliation: State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, People's Republic of China.
authors.forename: Yanning
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Shaoxing People's Hospital, Shaoxing Hospital Zhejiang University, Shaoxing, Zhejiang, People's Republic of China.
authors.forename: Xuejun
authors.initials: X
authors.lastname: Dong
keywords: ELK1; SPAG9; hepatocellular carcinoma; metastasis