Restoration of XAF1 expression induces apoptosis and inhibits tumor growth in gastric cancer.
XAF1 (XIAP-associated factor 1) is a novel XIAP binding protein that can antagonize XIAP and sensitize cells to other cell death triggers. Our previous results have shown that aberrant hypermethylation of the CpG sites in XAF1 promoter is strongly associated with lower expression of XAF1 in gastric cancers. In our study, we investigated the effect of restoration of XAF1 expression on growth of gastric cancers. We found that the restoration of XAF1 expression suppressed anchorage-dependent and -independent growth and increased sensitivity to TRAIL and drug-induced apoptosis. Stable cell clones expressing XAF1 exhibited delayed tumor initiation in nude mice. Restoration of XAF1 expression mediated by adenovirus vector greatly increased apoptosis in gastric cancer cell lines in a time- and dose-dependent manner and sensitized cancer cells to TRAIL and drugs-induced apoptosis. Adeno-XAF1 transduction induced cell cycle G2/M arrest and upregulated the expression of p21 and downregulated the expression of cyclin B1 and cdc2. Notably, adeno-XAF1 treatment significantly inhibited tumor growth, strongly enhanced the antitumor activity of TRAIL in a gastric cancer xenograft model in vivo, and significantly prolonged the survival time of animals bearing tumor xenografts. Complete eradication of established tumors was achieved on combined treatment with adeno-XAF1 and TRAIL. Our results document that the restoration of XAF1 inhibits gastric tumorigenesis and tumor growth and that XAF1 is a promising candidate for cancer gene therapy.
Tu
Shui Ping
SP
Department of Gastroenterology, Rui-jin Hospital, Shanghai Jiao Tong University School of Medicine, People's Republic of China.
Liston
Peter
P
Cui
Jian Tao
JT
Lin
Marie C M
MC
Jiang
Xiao Hua
XH
Yang
Yi
Y
Gu
Qing
Q
Jiang
Shi Hu
SH
Lum
Ching Tung
CT
Kung
Hsiang Fu
HF
Korneluk
Robert G
RG
Wong
Benjamin Chun-Yu
BC
D048868:Adaptor Proteins, Signal Transducing; D000256:Adenoviridae; D000818:Animals; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology*; D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins; D015153:Blotting, Western; D002453:Cell Cycle / Q000235:genetics; D045744:Cell Line, Tumor; D019926:Cyclin B / Q000378:metabolism; D056744:Cyclin B1; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism; D004195:Disease Models, Animal; D018450:Disease Progression; D015536:Down-Regulation; D004357:Drug Synergism; D015972:Gene Expression Regulation, Neoplastic; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors; D006801:Humans; D020287:In Situ Nick-End Labeling; D047908:Intracellular Signaling Peptides and Proteins; D051379:Mice; D008807:Mice, Inbred BALB C; D009363:Neoplasm Proteins / Q000378:metabolism* / Q000494:pharmacology* / Q000627:therapeutic use; D010957:Plasmids; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013274:Stomach Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology / Q000628:therapy*; D053221:TNF-Related Apoptosis-Inducing Ligand / Q000378:metabolism / Q000494:pharmacology; D013997:Time Factors; D014161:Transduction, Genetic; D014162:Transfection; D014183:Transplantation, Heterologous; D015854:Up-Regulation
D048868:Adaptor Proteins, Signal Transducing; D051017:Apoptosis Regulatory Proteins; C534699:CCNB1 protein, human; C534700:Ccnb1 protein, mouse; D019926:Cyclin B; D056744:Cyclin B1; D050759:Cyclin-Dependent Kinase Inhibitor p21; D047908:Intracellular Signaling Peptides and Proteins; D009363:Neoplasm Proteins; D053221:TNF-Related Apoptosis-Inducing Ligand; C417551:XAF1 protein, human