title: Complete elimination of colorectal tumor xenograft by combined manganese superoxide dismutase with tumor necrosis factor-related apoptosis-inducing ligand gene virotherapy.
abstract: Manganese superoxide dismutase (MnSOD) is a latent tumor suppressor gene. To investigate the therapeutic effect of MnSOD and its mechanisms, a replication-competent recombinant adenovirus with E1B 55-kDa gene deletion (ZD55) was constructed, and human MnSOD and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) genes were inserted to form ZD55-MnSOD and ZD55-TRAIL. ZD55-MnSOD exhibited an inhibition in tumor cell growth approximately 1,000-fold greater than Ad-MnSOD. ZD55-TRAIL was shown to induce the MnSOD expression in SW620 cells. Accordingly, by the combined use of ZD55-MnSOD with ZD55-TRAIL (i.e., "dual gene virotherapy"), all established colorectal tumor xenografts were completely eliminated in nude mice. The evidence exists that the MnSOD overexpression led to a slower tumor cell growth both in vitro and in vivo as a result of apoptosis caused by MnSOD and TRAIL overexpression after adenoviral transduction. Our results showed that the production of hydrogen peroxide derived from MnSOD dismutation activated caspase-8, which might down-regulate Bcl-2 expression and induce Bax translocation to mitochondria. Subsequently, Bax translocation enhanced the release of apoptosis-initiating factor and cytochrome c. Cytochrome c finally triggered apoptosis by activating caspase-9 and caspase-3 in apoptotic cascade. Bax-mediated apoptosis seems to be dependent on caspase-8 activation because the inhibition of caspase-8 prevented Bid processing and Bax translocation. In conclusion, our dual gene virotherapy completely eliminated colorectal tumor xenografts via enhanced apoptosis, and this novel strategy points toward a new direction of cancer treatment.
authors.affiliation: Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, China.
authors.forename: Yanhong
authors.initials: Y
authors.lastname: Zhang
authors.forename: Jinfa
authors.initials: J
authors.lastname: Gu
authors.forename: Lili
authors.initials: L
authors.lastname: Zhao
authors.forename: Lingfeng
authors.initials: L
authors.lastname: He
authors.forename: Wenbin
authors.initials: W
authors.lastname: Qian
authors.forename: Jinhui
authors.initials: J
authors.lastname: Wang
authors.forename: Yigang
authors.initials: Y
authors.lastname: Wang
authors.forename: Qijun
authors.initials: Q
authors.lastname: Qian
authors.forename: Cheng
authors.initials: C
authors.lastname: Qian
authors.forename: Jian
authors.initials: J
authors.lastname: Wu
authors.forename: Xin Yuan
authors.initials: XY
authors.lastname: Liu
mesh_terms: D000256:Adenoviridae / Q000201:enzymology / Q000235:genetics / Q000502:physiology*; D017501:Adenovirus E1B Proteins / Q000172:deficiency / Q000235:genetics; D000818:Animals; D017209:Apoptosis / Q000502:physiology; D051017:Apoptosis Regulatory Proteins / Q000096:biosynthesis / Q000235:genetics*; D053181:Caspase 8; D020169:Caspases / Q000378:metabolism; D015179:Colorectal Neoplasms / Q000201:enzymology / Q000235:genetics / Q000628:therapy* / Q000821:virology; D003131:Combined Modality Therapy; D003588:Cytopathogenic Effect, Viral; D004790:Enzyme Induction; D015316:Genetic Therapy / Q000379:methods*; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D008297:Male; D008562:Membrane Glycoproteins / Q000096:biosynthesis / Q000235:genetics*; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D050130:Oncolytic Virotherapy / Q000379:methods*; D013482:Superoxide Dismutase / Q000096:biosynthesis / Q000235:genetics*; D053221:TNF-Related Apoptosis-Inducing Ligand; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis / Q000235:genetics*; D014779:Virus Replication; D023041:Xenograft Model Antitumor Assays; D051028:bcl-2-Associated X Protein / Q000378:metabolism
chemical_list: D017501:Adenovirus E1B Proteins; D051017:Apoptosis Regulatory Proteins; D008562:Membrane Glycoproteins; D053221:TNF-Related Apoptosis-Inducing Ligand; C505653:TNFSF10 protein, human; C505654:Tnfsf10 protein, mouse; D014409:Tumor Necrosis Factor-alpha; D051028:bcl-2-Associated X Protein; D006861:Hydrogen Peroxide; D013482:Superoxide Dismutase; C505530:CASP8 protein, human; C505526:Casp8 protein, mouse; D053181:Caspase 8; D020169:Caspases