Downregulation of peroxiredoxin I by a novel fully human phage display recombinant antibody induces apoptosis and enhances radiation sensitization in A549 lung carcinoma cells.
BACKGROUND
Antibodies have been proved to be effective in cancer treatment. Peroxiredoxin I (Prx I) is a potential target for cancer radiotherapy. The aim of this article is to investigate the effect of a novel phage display single-chain variable fragment (scFv) antibody targeting Prx I on human lung carcinoma cell line A549 radiosensitivity and the underlying mechanisms.


METHODS
A549 cell radiosensitivity was measured by colony-forming assay; cell cycle, cell apoptosis, and intracellular reactive oxygen species (ROS) level were determined by flow cytometer; RAD51 and γ-H2AX expression was evaluated by Western blot; and caspase 3 expression was determined by immunocytochemistry. A nude mouse bearing A549 tumor was established, and radiation sensitivity was measured to verify the in vitro data.


RESULTS
Prx I scFv incubation significantly increased A549 cell radiosensitivity, and this might be through enhanced intracellular ROS level and caspase 3 expression. In addition, protein expression of radiosensitivity-related proteins, RAD51 and γ-H2AX, was also modulated. The nude mouse xenograft model bearing A549 tumor treated with Prx I scFv also exibited enhanced radiosensitivity compared with the PBS group.


CONCLUSIONS
These results suggested that Prx I scFv could become a new therapy candidate for lung cancer radiotherapy.
Department of Radiology, Basic Medicine College, Chongqing Medical University, Chongqing, P.R. China.
Qishuai
Q
Guo
Xi
X
Huang
Jun
J
Zhang
Yi
Y
Luo
Zhiping
Z
Peng
Shaolin
S
Li
D000818:Animals; D017209:Apoptosis / Q000276:immunology / Q000528:radiation effects; D045744:Cell Line, Tumor; D003131:Combined Modality Therapy; D015536:Down-Regulation; D005260:Female; D006801:Humans; D007128:Immunoglobulin Fragments / Q000276:immunology / Q000494:pharmacology*; D007150:Immunohistochemistry; D008175:Lung Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000532:radiotherapy / Q000628:therapy*; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D019151:Peptide Library; D054464:Peroxiredoxins / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D011838:Radiation-Sensitizing Agents / Q000494:pharmacology*; D023041:Xenograft Model Antitumor Assays
D007128:Immunoglobulin Fragments; D019151:Peptide Library; D011838:Radiation-Sensitizing Agents; D054464:Peroxiredoxins