Ether à go-go potassium channel expression in soft tissue sarcoma patients.
BACKGROUND
The expression of the human Eag1 potassium channel (Kv10.1) is normally restricted to the adult brain, but it has been detected in both tumour cell lines and primary tumours. Our purpose was to determine the frequency of expression of Eag1 in soft tissue sarcoma and its potential clinical implications.


RESULTS
We used specific monoclonal antibodies to determine the expression levels of Eag1 in soft tissue sarcomas from 210 patients by immunohistochemistry. Eag1 was expressed in 71% of all tumours, with frequencies ranging from 56% (liposarcoma) to 82% (rhabdomyosarcoma). We detected differences in expression levels depending on the histological type, but no association was seen between expression of this protein and sex, age, grade or tumour size. Four cell lines derived from relevant sarcoma histological types (fibrosarcoma and rhabdomyosarcoma) were tested for Eag1 expression by real-time RT-PCR. We found all four lines to be positive for Eag1. In these cell lines, blockage of Eag1 by RNA interference led to a decrease in proliferation.


CONCLUSIONS
Eag1 is aberrantly expressed in over 70% sarcomas. In sarcoma cell lines, inhibition of Eag1 expression and/or function leads to reduced proliferation. The high frequency of expression of Eag1 in primary tumours and the restriction of normal expression of the channel to the brain, suggests the application of this protein for diagnostic or therapeutic purposes.
Mello de Queiroz
Fernanda
F
Divisão de Farmacologia, Coordenação de Pesquisa, Instituto Nacional do Câncer, Rio de Janeiro, Brazil. queiroz@em.mpg.de
Suarez-Kurtz
Guilherme
G
Stühmer
Walter
W
Pardo
Luis A
LA
D000293:Adolescent; D000328:Adult; D000368:Aged; D000818:Animals; D014408:Biomarkers, Tumor / Q000378:metabolism; D016466:CHO Cells; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D006224:Cricetinae; D051638:Ether-A-Go-Go Potassium Channels / Q000037:antagonists & inhibitors / Q000378:metabolism*; D005260:Female; D015870:Gene Expression; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008080:Liposarcoma / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D034622:RNA Interference; D012208:Rhabdomyosarcoma / Q000378:metabolism; D012509:Sarcoma / Q000378:metabolism*; D012983:Soft Tissue Neoplasms / Q000378:metabolism; D013048:Specimen Handling; D014162:Transfection
D014408:Biomarkers, Tumor; D051638:Ether-A-Go-Go Potassium Channels; C496884:KCNH1 protein, human