Production of endothelin-1 and big-endothelin-1 by tumor cells with epithelial-like morphology.
Immunoreactive endothelin (ET) and big-endothelin (big-ET) in conditioned media of endothelial and of non-endothelial cells were studied using sandwich-type enzyme immunoassays. Immunoreactivities of both ETs were detected in the media of all four endothelial cells tested. Among non-endothelial cells, tumor cell lines with epithelial-like morphology also produced immunoreactive ET and/or big-ET, although the total amount of ETs was one or two orders of magnitude less than that produced by PAE (porcine aortic endothelial cells). Immunoreactive ETs produced by HepG-2 (human hepatocellular carcinoma) and some other cells were characterized by gel-filtration HPLC and reverse-phase HPLC. These studies revealed the production of ET-1 and human big-ET-1 by these cells, although the immunoreactive ETs produced by the tumor cells were more heterogeneous than those produced by endothelial cells. The regulatory effects of thrombin and transforming growth factor-beta (TGF-beta) on the production of ETs were investigated. TGF-beta markedly stimulated the production of both ETs in HepG-2 and slightly decreased the big-ET level in A549 (human lung carcinoma). HPLC analysis showed that the major immunoreactive ETs induced by TGF-beta in HepG-2 were identical to ET-1 and human big-ET-1. These results demonstrated that production of ET-1 and big-ET-1 was not restricted to endothelial cells and was induced by TGF-beta in HepG-2 at the same levels as those produced by PAE.
Suzuki
N
N
Tsukuba Research Laboratories, Takeda Chemical Industries, Ltd., Ibaraki.
Matsumoto
H
H
Kitada
C
C
Kimura
S
S
Fujino
M
M
D000911:Antibodies, Monoclonal; D002851:Chromatography, High Pressure Liquid; D016232:Endothelins; D004847:Epithelial Cells; D004848:Epithelium / Q000378:metabolism; D006801:Humans; D007124:Immunoenzyme Techniques; D010452:Peptide Biosynthesis; D011498:Protein Precursors / Q000096:biosynthesis*; D013917:Thrombin / Q000502:physiology; D015291:Transforming Growth Factors / Q000502:physiology; D014407:Tumor Cells, Cultured / Q000378:metabolism*
D000911:Antibodies, Monoclonal; D016232:Endothelins; D011498:Protein Precursors; D015291:Transforming Growth Factors; D013917:Thrombin