Expression of voltage-gated potassium channels in human and mouse colonic carcinoma.
OBJECTIVE
Voltage-gated Kv potassium channels, like ether a go-go (EAG) channels, have been recognized for their oncogenic potential in breast cancer and other malignant tumors.


METHODS
We examined the molecular and functional expression of Kv channels in human colonic cancers and colon of mice treated with the chemical carcinogens dimethylhydrazine and N-methyl-N-nitrosourea. The data were compared with results from control mice and animals with chemically induced DSS colitis.


RESULTS
Electrogenic salt transport by amiloride-sensitive Na+ channels and cyclic AMP-activated cystic fibrosis transmembrane conductance regulator Cl- channels were attenuated during tumor development and colitis, whereas Ca2+-dependent transport remained unchanged. Kv channels, in particular Eag-1, were enhanced during carcinogenesis. Multiplex reverse transcription-PCR showed increased mRNA expression for Kv1.3, Kv1.5, Kv3.1, and members of the Eag channel family, after dimethylhydrazine and N-methyl-N-nitrosourea treatment. Eag-1 protein was detected in the malignant mouse colon and human colonic cancers. Genomic amplification of Eag-1 was found in 3.4% of all human colorectal adenocarcinoma and was an independent marker of adverse prognosis.


CONCLUSIONS
The study predicts an oncogenic role of Kv and Eag channels for the development of colonic cancer. These channels may represent an important target for a novel pharmacotherapy of colonic cancer.
Ousingsawat
Jiraporn
J
Institut für Physiologie, Universität Regensburg, Regensburg, Germany, and Institute for Pathology, University Hospital Basel, Basel, Switzerland.
Spitzner
Melanie
M
Puntheeranurak
Supaporn
S
Terracciano
Luigi
L
Tornillo
Luigi
L
Bubendorf
Lukas
L
Kunzelmann
Karl
K
Schreiber
Rainer
R
D000368:Aged; D000818:Animals; D001943:Breast Neoplasms; D003106:Colon / Q000378:metabolism; D003110:Colonic Neoplasms / Q000378:metabolism* / Q000473:pathology*; D004238:Diverticulitis / Q000378:metabolism; D004847:Epithelial Cells / Q000378:metabolism; D051638:Ether-A-Go-Go Potassium Channels / Q000378:metabolism; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007249:Inflammation; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D024642:Potassium Channels, Voltage-Gated / Q000096:biosynthesis* / Q000737:chemistry
D051638:Ether-A-Go-Go Potassium Channels; D024642:Potassium Channels, Voltage-Gated