Characteristics of alpha-adrenoceptors in two human colorectal cancer cell lines.
The DiFi and HT-29 human colorectal cancer cell lines were characterized and compared with respect to binding properties of alpha adrenoceptors present on the cell surface. Both cell lines possessed alpha-1 and alpha-2 adrenoceptors of high affinity; however, DiFi cells were rich in alpha-1 adrenoceptors, whereas HT-29 cells were rich in alpha-2 adrenoceptors. In each cell line, specificity of radioligand binding to alpha-1 or alpha-2 adrenoceptors was proved via competition studies using non-tritiated drugs. We believe this to be the first characterization of alpha-1 adrenoceptors in cell line HT-29 and of alpha-1 and alpha-2 adrenoceptors in DiFi cells. Differences between these cell lines in alpha adrenoceptor expression are discussed in relation to colon carcinogenesis. The high level of alpha-1 adrenoceptors seen in DiFi cells should make this cell line useful in studies of the function and regulation of this adrenoceptor subtype.
Agrawal
D K
DK
Department of Internal Medicine, Creighton University School of Medicine, Omaha, Nebraska 68178.
Wildrick
D M
DM
Boman
B M
BM
D001667:Binding, Competitive; D015179:Colorectal Neoplasms / Q000378:metabolism*; D006801:Humans; D011224:Prazosin / Q000378:metabolism; D011942:Receptors, Adrenergic, alpha / Q000378:metabolism*; D014407:Tumor Cells, Cultured; D015016:Yohimbine / Q000378:metabolism
D011942:Receptors, Adrenergic, alpha; D015016:Yohimbine; D011224:Prazosin