Endothelin-1 is an autocrine/paracrine growth factor for human cancer cell lines.
We studied whether a novel vasoconstrictor peptide, endothelin-1 (ET-1), is synthesized by and released from human carcinoma cell lines, and whether ET-1 stimulates proliferation of these tumor cells. ET-1-like immunoreactivity was released from both HeLa and HEp-2 cells as a function of time. Reverse-phase HPLC of the conditioned media from HeLa cells revealed a major peak coeluting with standard ET-1. Northern blot analysis demonstrated the expression of mRNA for ET-1 precursor in both tumor cell lines. Both cell lines contained a single class of specific binding sites for ET-1. ET-1 dose-dependently induced increases in cytosolic free Ca2+ concentration in fura-2-loaded tumor cells, whose effect was completely abolished by chelating extracellular Ca2+ or by Ca(2+)-channel blocker. ET-1 stimulated proliferation of the quiescent cell lines in a dose-dependent manner, whose effect was inhibited by Ca(2+)-channel blocker. Polyclonal antibody for ET-1 inhibited proliferation of these cell lines, whereas nonimmune serum had no effect. These results demonstrate that ET-1 is synthesized by and released from human epithelial carcinoma cell lines, and that exogenous and endogenous ET-1 stimulates proliferation of the cells possibly through Ca2+ influx, suggesting its role as an autocrine/paracrine growth factor for certain tumor cells.
Shichiri
M
M
Department of Medicine, Tokyo Medical and Dental University, Japan.
Hirata
Y
Y
Nakajima
T
T
Ando
K
K
Imai
T
T
Yanagisawa
M
M
Masaki
T
T
Marumo
F
F
D002118:Calcium / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D016232:Endothelins / Q000032:analysis / Q000235:genetics / Q000494:pharmacology*; D006133:Growth Substances / Q000494:pharmacology*; D006367:HeLa Cells; D006801:Humans; D014407:Tumor Cells, Cultured
D016232:Endothelins; D006133:Growth Substances; D002118:Calcium