title: Bifidobacterial recombinant thymidine kinase-ganciclovir gene therapy system induces FasL and TNFR2 mediated antitumor apoptosis in solid tumors.
abstract: Directly targeting therapeutic suicide gene to a solid tumor is a hopeful approach for cancer gene therapy. Treatment of a solid tumor by an effective vector for a suicide gene remains a challenge. Given the lack of effective treatments, we constructed a bifidobacterial recombinant thymidine kinase (BF-rTK) -ganciclovir (GCV) targeting system (BKV) to meet this requirement and to explore antitumor mechanisms.
  
  
  
  Bifidobacterium (BF) or BF-rTK was injected intratumorally with or without ganciclovir in a human colo320 intestinal xenograft tumor model. The tumor tissues were analyzed using apoptosis antibody arrays, real time PCR and western blot. The colo320 cell was analyzed by the gene silencing method. Autophagy and necroptosis were also detected in colo320 cell. Meanwhile, three human digestive system xenograft tumor models (colorectal cancer colo320, gastric cancer MKN-45 and liver cancer SSMC-7721) and a breast cancer (MDA-MB-231) model were employed to validate the universality of BF-rTK + GCV in solid tumor gene therapy. The survival rate was evaluated in three human cancer models after the BF-rTK + GCV intratumor treatment. The analysis of inflammatory markers (TNF-α) in tumor indicated that BF-rTK + GCV significantly inhibited TNF-α expression.
  
  
  
  The results suggested that BF-rTK + GCV induced tumor apoptosis without autophagy and necroptosis occurrence. The apoptosis was transduced by multiple signaling pathways mediated by FasL and TNFR2 and mainly activated the mitochondrial control of apoptosis via Bid and Bim, which was rescued by silencing Bid or/and Bim. However, BF + GCV only induced apoptosis via Fas/FasL signal pathway accompanied with increased P53 expression. We further found that BF-rTK + GCV inhibited the expression of the inflammatory maker of TNF-α. However, BF-rTK + GCV did not result in necroptosis and autophagy.
  
  
  
  BF-rTK + GCV induced tumor apoptosis mediated by FasL and TNFR2 through the mitochondrial control of apoptosis via Bid and Bim without inducing necroptosis and autophagy. Furthermore, BF-rTK + GCV showed to repress the inflammation of tumor through downregulating TNF-α expression. Survival analysis results of multiple cancer models confirmed that BF-rTK + GCV system has a wide field of application in solid tumor gene therapy.
authors.affiliation: Department of Biochemistry & Molecular Biology, Molecular Medicine & Cancer Research Center, Chongqing Medical University, Yuzhong District, Yi XueYuan Road, No 1, Chongqing, 400016, People's Republic of China.
authors.forename: Changdong
authors.initials: C
authors.lastname: Wang
authors.affiliation: Department of Biochemistry & Molecular Biology, Molecular Medicine & Cancer Research Center, Chongqing Medical University, Yuzhong District, Yi XueYuan Road, No 1, Chongqing, 400016, People's Republic of China. yongpingm@yahoo.com.
authors.forename: Yongping
authors.initials: Y
authors.lastname: Ma
authors.affiliation: Department of Biochemistry & Molecular Biology, Molecular Medicine & Cancer Research Center, Chongqing Medical University, Yuzhong District, Yi XueYuan Road, No 1, Chongqing, 400016, People's Republic of China.
authors.forename: Qiongwen
authors.initials: Q
authors.lastname: Hu
authors.affiliation: Department of Biochemistry & Molecular Biology, Molecular Medicine & Cancer Research Center, Chongqing Medical University, Yuzhong District, Yi XueYuan Road, No 1, Chongqing, 400016, People's Republic of China.
authors.forename: Tingting
authors.initials: T
authors.lastname: Xie
authors.affiliation: Department of Biochemistry & Molecular Biology, Molecular Medicine & Cancer Research Center, Chongqing Medical University, Yuzhong District, Yi XueYuan Road, No 1, Chongqing, 400016, People's Republic of China.
authors.forename: Jiayan
authors.initials: J
authors.lastname: Wu
authors.affiliation: Department of Biochemistry & Molecular Biology, Molecular Medicine & Cancer Research Center, Chongqing Medical University, Yuzhong District, Yi XueYuan Road, No 1, Chongqing, 400016, People's Republic of China.
authors.forename: Fan
authors.initials: F
authors.lastname: Zeng
authors.affiliation: Department of Biochemistry & Molecular Biology, Molecular Medicine & Cancer Research Center, Chongqing Medical University, Yuzhong District, Yi XueYuan Road, No 1, Chongqing, 400016, People's Republic of China.
authors.forename: Fangzhou
authors.initials: F
authors.lastname: Song
mesh_terms: D000818:Animals; D017209:Apoptosis; D001644:Bifidobacterium / Q000502:physiology*; D045744:Cell Line, Tumor; D003131:Combined Modality Therapy; D053222:Fas Ligand Protein / Q000235:genetics* / Q000378:metabolism; D015774:Ganciclovir / Q000008:administration & dosage* / Q000627:therapeutic use; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D041722:Genes, Transgenic, Suicide; D015316:Genetic Therapy; D005822:Genetic Vectors / Q000008:administration & dosage; D006801:Humans; D051379:Mice; D009369:Neoplasms / Q000235:genetics / Q000628:therapy*; D047889:Receptors, Tumor Necrosis Factor, Type II / Q000235:genetics* / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics; D013937:Thymidine Kinase / Q000235:genetics*; D023041:Xenograft Model Antitumor Assays
chemical_list: C505661:FASLG protein, human; D053222:Fas Ligand Protein; D047889:Receptors, Tumor Necrosis Factor, Type II; D011994:Recombinant Proteins; C415902:TNFRSF1B protein, human; D013937:Thymidine Kinase; D015774:Ganciclovir
keywords: Apoptosis; Bifidobacterium; Ganciclovir; Thymidine kinase; Tumor gene therapy