Upregulation of vascular endothelial growth factor by hydrogen peroxide in human colon cancer.
OBJECTIVE
To evaluate the effect of reactive oxygen species such as hydrogen peroxide on the progression of human colon cancer.


METHODS
Human colon carcinoma cell lines, LS174T and HCT8, were treated respectively with 10(-5), 10(-7) or 10(-9) mol x L(-1) hydrogen peroxide for 24h,and co-cultured with human endothelial cell line ECV-304. The migration of ECV-304 induced by cancer cells was calculated and the expression level of vascular endothelial growth factor in cancer cells was determined by RT-PCR analysis and ELISA. Dactinomycin of 1.5mg x L(-1) which could block transcription of cancer cells was applied to observing the effects of H(2)O(2) on transcriptional activity and the relative half-life of VEGF mRNA. Finally,to evaluate the effect of H2O2 on NF-kappaB activity in colon cancer cells, NF-kappaB in cytoplasm and nucleus of the cells were detected with FITC-tagged antibody and its presence in the nucleus(Fn) vs cytoplasm(Fc) was monitored by measuring the green fluorescence integrated over the nucleus by laser scanning cytometry(LSC).


RESULTS
Exogenouse hydrogen peroxide of low concentration increased the migration of endothelial cell induced by colon cancer cells. When cancer cells were treated with 10(-5) mol x L(-1) H2O2, the migration number of endothelial cells induced by LS174T cells was 203+/-70 and the number induced by HCT8 cells was 145+/-65. The two values were significantly higher than those treated with other concentrations of H2O2 (P<0.01). The expression of vascular endothelial growth factor in cancer cells, which could be blocked by dactinomycin, were increased to a certain degree, while the relative half-life of VEGF mRNA was not prolonged after treatment with hydrogen peroxide. The activity of NF-kappaB in colon cells rose after the cells were exposed to hydrogen peroxide for 24h. The Fn values in HCT8 cells were 91+/-13 (0 mol x L(-1) H2O2) and 149+/-40(10(-5) mol x L(-1) H2O2)(P<0.05), in LS174T cells were 127+/-35(0 mol x L(-1) H2O2) and 192+/-11(10(-5)mol x L(-1) H2O2) (P<0.05). It is similar to the case of VEGF expression in cancer cells.


CONCLUSIONS
Hydrogen peroxide increases vascular endothelial growth factor expression in colon cancer cells, and it is likely that reactive oxygen species such as hydrogen peroxide facilitates the development of colon cancer.
Zhu
Jian-Wei
JW
Shanghai Institute of Digestive Sugery,Ruijin Hospital,Shanghai Second Medical University,Shanghai 200025,China. tozhujw@263.net
Yu
Bao-Ming
BM
Ji
Yu-Bao
YB
Zheng
Ming-Hua
MH
Li
Dong-Hua
DH
D000975:Antioxidants / Q000494:pharmacology*; D002455:Cell Division; D002465:Cell Movement / Q000187:drug effects; D003110:Colonic Neoplasms; D016228:Endothelial Growth Factors / Q000235:genetics*; D004730:Endothelium, Vascular / Q000166:cytology; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D008222:Lymphokines / Q000235:genetics*; D016328:NF-kappa B / Q000378:metabolism; D018384:Oxidative Stress; D012333:RNA, Messenger / Q000032:analysis; D017382:Reactive Oxygen Species / Q000378:metabolism; D014407:Tumor Cells, Cultured / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D014471:Umbilical Veins / Q000166:cytology; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
D000975:Antioxidants; D016228:Endothelial Growth Factors; D008222:Lymphokines; D016328:NF-kappa B; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D006861:Hydrogen Peroxide