title: Molecular characterization of severin from Clonorchis sinensis excretory/secretory products and its potential anti-apoptotic role in hepatocarcinoma PLC cells.
abstract: BACKGROUND
  Clonorchiasis, caused by the infection of Clonorchis sinensis (C. sinensis), is a kind of neglected tropical disease, but it is highly related to cholangiocarcinoma and hepatocellular carcinoma (HCC). It has been well known that the excretory/secretory products of C. sinensis (CsESPs) play key roles in clonorchiasis associated carcinoma. From genome and transcriptome of C. sinensis, we identified one component of CsESPs, severin (Csseverin), which had three putative gelsolin domains. Its homologues are supposed to play a vital role in apoptosis resistance of tumour cell.
  
  
  RESULTS
  There was significant similarity in tertiary structures between human gelsolin and Csseverin by bioinformatics analysis. We identified that Csseverin expressed at life stage of adult worm, metacercaria and egg by the method of quantitative real-time PCR and western blotting. Csseverin distributed in vitellarium and intrauterine eggs of adult worm and tegument of metacercaria by immunofluorence assay. We obtained recombinant Csseverin (rCsseverin) and confirmed that rCsseverin could bind with calciumion in circular dichroism spectrum analysis. It was demonstrated that rCsseverin was of the capability of actin binding by gel overlay assay and immunocytochemistry. Both Annexin V/PI assay and mitochondrial membrane potential assay of human hepatocarcinoma cell line PLC showed apoptosis resistance after incubation with different concentrations of rCsseverin. Morphological analysis, apoptosis-associated changes of mitochondrial membrane potential and Annexin V/PI apoptosis assay showed that co-incubation of PLC cells with rCsseverin in vitro led to an inhibition of apoptosis induced by serum-starved for 24 h.
  
  
  CONCLUSIONS
  Collectively, the molecular properties of Csseverin, a molecule of CsESPs, were characterized in our study. rCsseverin could cause obvious apoptotic inhibition in human HCC cell line. Csseverin might exacerbate the process of HCC patients combined with C. sinensis infection.
authors.affiliation: Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, People's Republic of China ; Key Laboratory of Tropical Diseases Control at Sun Yat-sen University, Ministry of Education, Guangzhou, People's Republic of China.
authors.forename: Xueqing
authors.initials: X
authors.lastname: Chen
authors.affiliation: Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, People's Republic of China ; Key Laboratory of Tropical Diseases Control at Sun Yat-sen University, Ministry of Education, Guangzhou, People's Republic of China.
authors.forename: Shan
authors.initials: S
authors.lastname: Li
authors.affiliation: Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, People's Republic of China ; Key Laboratory of Tropical Diseases Control at Sun Yat-sen University, Ministry of Education, Guangzhou, People's Republic of China.
authors.forename: Lei
authors.initials: L
authors.lastname: He
authors.affiliation: Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, People's Republic of China ; Key Laboratory of Tropical Diseases Control at Sun Yat-sen University, Ministry of Education, Guangzhou, People's Republic of China.
authors.forename: Xiaoyun
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, People's Republic of China ; Key Laboratory of Tropical Diseases Control at Sun Yat-sen University, Ministry of Education, Guangzhou, People's Republic of China.
authors.forename: Pei
authors.initials: P
authors.lastname: Liang
authors.affiliation: Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, People's Republic of China ; Key Laboratory of Tropical Diseases Control at Sun Yat-sen University, Ministry of Education, Guangzhou, People's Republic of China.
authors.forename: Wenjun
authors.initials: W
authors.lastname: Chen
authors.affiliation: Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, People's Republic of China ; Key Laboratory of Tropical Diseases Control at Sun Yat-sen University, Ministry of Education, Guangzhou, People's Republic of China.
authors.forename: Meng
authors.initials: M
authors.lastname: Bian
authors.affiliation: Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, People's Republic of China ; Key Laboratory of Tropical Diseases Control at Sun Yat-sen University, Ministry of Education, Guangzhou, People's Republic of China.
authors.forename: Mengyu
authors.initials: M
authors.lastname: Ren
authors.affiliation: Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, People's Republic of China ; Key Laboratory of Tropical Diseases Control at Sun Yat-sen University, Ministry of Education, Guangzhou, People's Republic of China.
authors.forename: Jinsi
authors.initials: J
authors.lastname: Lin
authors.affiliation: Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, People's Republic of China ; Key Laboratory of Tropical Diseases Control at Sun Yat-sen University, Ministry of Education, Guangzhou, People's Republic of China.
authors.forename: Chi
authors.initials: C
authors.lastname: Liang
authors.affiliation: Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, People's Republic of China ; Key Laboratory of Tropical Diseases Control at Sun Yat-sen University, Ministry of Education, Guangzhou, People's Republic of China.
authors.forename: Jin
authors.initials: J
authors.lastname: Xu
authors.affiliation: Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, People's Republic of China ; Key Laboratory of Tropical Diseases Control at Sun Yat-sen University, Ministry of Education, Guangzhou, People's Republic of China.
authors.forename: Zhongdao
authors.initials: Z
authors.lastname: Wu
authors.affiliation: Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, People's Republic of China ; Key Laboratory of Tropical Diseases Control at Sun Yat-sen University, Ministry of Education, Guangzhou, People's Republic of China.
authors.forename: Xuerong
authors.initials: X
authors.lastname: Li
authors.affiliation: Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, People's Republic of China ; Key Laboratory of Tropical Diseases Control at Sun Yat-sen University, Ministry of Education, Guangzhou, People's Republic of China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Huang
authors.affiliation: Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, People's Republic of China ; Key Laboratory of Tropical Diseases Control at Sun Yat-sen University, Ministry of Education, Guangzhou, People's Republic of China.
authors.forename: Xinbing
authors.initials: X
authors.lastname: Yu
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D051017:Apoptosis Regulatory Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D045744:Cell Line, Tumor; D003004:Clonorchis sinensis / Q000235:genetics*; D020869:Gene Expression Profiling; D015801:Helminth Proteins / Q000737:chemistry* / Q000378:metabolism; D022781:Hepatocytes / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D011485:Protein Binding; D011487:Protein Conformation; D017386:Sequence Homology, Amino Acid; D014018:Tissue Distribution
chemical_list: D000199:Actins; D051017:Apoptosis Regulatory Proteins; D015801:Helminth Proteins; D002118:Calcium