Role of peroxiredoxin I in rectal cancer and related to p53 status.
BACKGROUND
Neoadjuvant chemoradiotherapy is widely accepted for the treatment of localized rectal cancer. Although peroxiredoxin I (PrxI) and p53 have been implicated in carcinogenesis and cancer treatment, the role of PrxI and its interaction with p53 in the prognosis and treatment response of rectal cancer remain relatively unstudied.


METHODS
In the present study, we examined the levels of PrxI and p53 in rectal cancer patients using membrane arrays and compared them with normal population samples. To demonstrate the biologic changes after manipulation of PrxI expression, we established stable transfectants of HCT-116 (wild-type p53) and HT-29 (mutant p53) cells with a PrxI silencing vector. The predictive capacities of PrxI and p53 were also assessed by relating the immunohistochemical staining of a retrospective series of rectal cancer cases to the clinical outcome.


RESULTS
The membrane array and immunochemical staining data showed that PrxI, but not p53, was significantly associated with the tumor burden. Our immunochemistry findings further indicated that PrxI positivity was linked to a poor response to neoadjuvant therapy and worse survival. In cellular and animal experiments, the inhibition of PrxI significantly decreased tumor growth and sensitized the tumor to irradiation, as indicated by a lower capacity to scavenge reactive oxygen species and more extensive DNA damage. The p53 status might have contributed to the difference between HCT-116 and HT-29 after knockdown of PrxI.


CONCLUSIONS
According to our data, the level of PrxI combined with the p53 status is relevant to the prognosis and the treatment response. We suggested that PrxI might be a new biomarker for rectal cancer.
Chen
Miao-Fen
MF
Chang Gung University College of Medicine and Chang Gung Institute of Technology, Kwei-Shan,Taoyuan, Taiwan.
Lee
Kuan-Der
KD
Yeh
Chung-Hung
CH
Chen
Wen-Cheng
WC
Huang
Wen-Shih
WS
Chin
Chih-Chien
CC
Lin
Paul-Yang
PY
Wang
Jeng-Yi
JY
D000818:Animals; D014408:Biomarkers, Tumor / Q000032:analysis* / Q000037:antagonists & inhibitors / Q000235:genetics; D016022:Case-Control Studies; D019008:Drug Resistance, Neoplasm; D020868:Gene Silencing; D045325:HCT116 Cells; D019073:HT29 Cells; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D051379:Mice; D008819:Mice, Nude; D020360:Neoadjuvant Therapy / Q000379:methods; D009363:Neoplasm Proteins / Q000032:analysis* / Q000037:antagonists & inhibitors / Q000235:genetics; D009360:Neoplastic Cells, Circulating / Q000737:chemistry / Q000473:pathology; D054464:Peroxiredoxins / Q000032:analysis* / Q000037:antagonists & inhibitors / Q000235:genetics; D011379:Prognosis; D040081:Protein Array Analysis / Q000379:methods; D016315:Proto-Oncogene Proteins c-abl / Q000032:analysis; D012372:ROC Curve; D011836:Radiation Tolerance; D017382:Reactive Oxygen Species / Q000378:metabolism; D012004:Rectal Neoplasms / Q000737:chemistry* / Q000188:drug therapy / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy; D012189:Retrospective Studies; D016019:Survival Analysis; D014183:Transplantation, Heterologous; D016896:Treatment Outcome; D047368:Tumor Burden; D016159:Tumor Suppressor Protein p53 / Q000032:analysis* / Q000037:antagonists & inhibitors / Q000235:genetics
D014408:Biomarkers, Tumor; D009363:Neoplasm Proteins; D017382:Reactive Oxygen Species; D016159:Tumor Suppressor Protein p53; D054464:Peroxiredoxins; D016315:Proto-Oncogene Proteins c-abl