Radiotherapy sensitization by tumor-specific TRAIL gene targeting improves survival of mice bearing human non-small cell lung cancer.
OBJECTIVE
To sensitize non-small cell lung cancer (NSCLC) to radiotherapy by tumor-specific delivery of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) gene.


METHODS
The TRAIL was delivered to human NSCLC cell lines and normal human bronchial epithelial cells by the replication-defective adenoviral vector Ad/TRAIL-F/RGD using a tumor-specific human telomerase reverse transcriptase promoter. Cancer growth was studied using 2,3-bis[2-methoxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxanilide inner salt and clonogenic assays. Activation of the apoptosis pathway was analyzed in a Western blot and sub-G(1) DNA accumulation. A xenograft mouse lung cancer model was treated by intratumoral injections of Ad/TRAIL-F/RGD and local radiotherapy; the other groups received one of these treatments alone or a control agent. Apoptosis and TRAIL expression in tumors were also analyzed.


RESULTS
Ad/TRAIL-F/RGD specifically targets human NSCLC cells without significant effect in normal human bronchial epithelial cells. The combination of Ad/TRAIL-F/RGD and radiotherapy significantly improved cell-killing effect in all NSCLC cell lines tested (P < 0.05). Expression of TRAIL showed a dose-dependent relationship with Ad/TRAIL-F/RGD, and radiation seemed to increase TRAIL expression. Activation of the apoptosis by TRAIL and radiation was shown by activation of caspase-9, caspase-8, caspase-3, and poly(ADP-ribose) polymerase and increased DNA sub-G(1) accumulation. The combination of TRAIL and radiotherapy significantly increased apoptosis in vivo, inhibited tumor growth, and prolonged mean survival in mice bearing human NSCLC to 43.7 days compared with 23.7 days (TRAIL only) and 16.5 days (radiotherapy only; P < 0.05).


CONCLUSIONS
The combination of Ad/TRAIL-F/RGD and radiotherapy significantly improved therapeutic efficacy in suppressing NSCLC tumor growth and prolonging survival. Ad/TRAIL-F/RGD may improve the therapeutic ratio of radiotherapy in NSCLC.
Zhang
Xiaochun
X
Department of Experimental Radiation Oncology, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA.
Cheung
Rex Min
RM
Komaki
Ritsuko
R
Fang
Bingliang
B
Chang
Joe Y
JY
D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D017209:Apoptosis / Q000235:genetics / Q000528:radiation effects; D051017:Apoptosis Regulatory Proteins; D015153:Blotting, Western; D002289:Carcinoma, Non-Small-Cell Lung / Q000473:pathology / Q000532:radiotherapy* / Q000628:therapy; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000235:genetics / Q000528:radiation effects; D003131:Combined Modality Therapy; D005260:Female; D015316:Genetic Therapy / Q000379:methods; D005822:Genetic Vectors / Q000008:administration & dosage / Q000235:genetics; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008175:Lung Neoplasms / Q000473:pathology / Q000532:radiotherapy* / Q000628:therapy; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008819:Mice, Nude; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D016019:Survival Analysis; D053221:TNF-Related Apoptosis-Inducing Ligand; D013997:Time Factors; D016896:Treatment Outcome; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000378:metabolism*; D023041:Xenograft Model Antitumor Assays / Q000379:methods*; D018631:ras Proteins / Q000235:genetics
D051017:Apoptosis Regulatory Proteins; D008562:Membrane Glycoproteins; D011993:Recombinant Fusion Proteins; D053221:TNF-Related Apoptosis-Inducing Ligand; C505653:TNFSF10 protein, human; C505654:Tnfsf10 protein, mouse; D014409:Tumor Necrosis Factor-alpha; D049452:Green Fluorescent Proteins; D018631:ras Proteins