title: A small interfering RNA targeting the KLF6 splice variant, KLF6-SV1, as gene therapy for gastric cancer.
abstract: BACKGROUND
  Accumulating evidence suggests that the tumor suppressor gene Kruppel-like factor 6 (KLF6) and its dominant-negative splice form KLF6-SV1 play important roles in both the development and progression of cancer. However, the role of KLF6-SV1 in gastric cancer remains largely unknown.
  
  
  METHODS
  KLF6-SV1 expression was detected in various human gastric cancer cell lines and gastric cancer patient samples by reverse transcriptase polymerase chain reaction (RT-PCR) and Western blotting. Small interfering RNA (siRNA) was used to inhibit KLF6-SV1 expression in BGC-823 and SGC-7901 cell lines. The effects of downregulation of KLF6-SV1 by siRNA on cell proliferation, migration, invasion, and tumor growth were examined in vitro and in vivo.
  
  
  RESULTS
  Overexpression of KLF6-SV1 was detected in tumor samples from gastric cancer patients, and in various differentiated gastric cancer cell lines. In vitro downregulation of KLF6-SV1 by siRNA inhibited BGC-823 and SGC-7901 cell proliferation, anchorage-independent growth, migration, and invasion through the altered expression of Ki-67, vascular endothelial growth factor (VEGF), E-cadherin, and matrix metalloproteinase (MMP)-9. Also, KLF6-SV1 silencing promoted caspase-dependent apoptosis of BGC-823 and SGC-7901 cells via the regulation of phosphatidylinositol 3-OH kinase (PI3K)/Akt activity and Bcl-2-related protein expression. In vivo animal studies showed that KLF6-SV1 siRNA significantly inhibited the tumorigenicity of BGC-823 and SGC-7901 cells. Gene therapy with polyethylenimine/si-SV1 intratumoral injection also resulted in the suppression of tumor growth and prolonged animal survival in an established xenograft tumor model.
  
  
  CONCLUSIONS
  These data demonstrate that KLF6-SV1 is an important regulator of the growth, migration, invasion, and survival of gastric cancer cells, and downregulation of KLF6-SV1 by siRNA may offer a new potential gene therapy approach for gastric cancer.
authors.affiliation: Department of General Surgery, Third Affiliated Hospital of Harbin Medical University, Harbin, People's Republic of China.
authors.forename: Hui
authors.initials: H
authors.lastname: Chen
authors.forename: Lili
authors.initials: L
authors.lastname: Chen
authors.forename: Lingyu
authors.initials: L
authors.lastname: Sun
authors.forename: Hongqun
authors.initials: H
authors.lastname: Zhen
authors.forename: Xiaomei
authors.initials: X
authors.lastname: Li
authors.forename: Qifan
authors.initials: Q
authors.lastname: Zhang
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D017209:Apoptosis / Q000235:genetics; D015820:Cadherins / Q000235:genetics; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000235:genetics; D049109:Cell Proliferation; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D015552:Injections, Intralesional; D019394:Ki-67 Antigen / Q000235:genetics; D000075723:Kruppel-Like Factor 6; D051741:Kruppel-Like Transcription Factors / Q000235:genetics*; D008297:Male; D020780:Matrix Metalloproteinase 9 / Q000235:genetics; D051379:Mice; D008819:Mice, Nude; D008875:Middle Aged; D011094:Polyethyleneimine / Q000008:administration & dosage; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D034741:RNA, Small Interfering / Q000008:administration & dosage* / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013274:Stomach Neoplasms / Q000235:genetics* / Q000473:pathology / Q000628:therapy; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics; D023041:Xenograft Model Antitumor Assays
chemical_list: D015820:Cadherins; C105465:KLF6 protein, human; D019394:Ki-67 Antigen; D000075723:Kruppel-Like Factor 6; D051741:Kruppel-Like Transcription Factors; D011518:Proto-Oncogene Proteins; D034741:RNA, Small Interfering; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D011094:Polyethyleneimine; D051057:Proto-Oncogene Proteins c-akt; D020780:Matrix Metalloproteinase 9