Platelet-activating factor in human endometrium.
Platelet-activating factor (PAF) is a phospholipid actively produced by human endometrium and deeply involved in the processes of ovoimplantation and labor. We recently found that PAF represents a new autocrine growth factor for a human adenocarcinoma cell line, HEC-1A. Indeed, biologically active PAF is synthesized by HEC-1A cells, under progesterone control. In HEC-1A cells, PAF regulates intracellular calcium concentration ([Ca2+]), DNA synthesis and expression of early oncogenes. All these effects are blocked by the receptor antagonist L659,989. However, while nanomolar concentrations of PAF mobilize [Ca2+], only micromolar concentrations affect cell growth, suggesting heterogeneity of PAF receptors or signaling. Two distinct populations of PAF receptors are present in HEC-1A cells, which bind PAF in nanomolar and micromolar concentrations, respectively. Since HEC-1A cells are producing elevated concentrations of PAF and micromolar concentrations of the PAF antagonist L659,989 inhibit cell proliferation, an autocrine role for PAF is suggested in HEC-1A cells.
Baldi
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Dipartimento di Fisiopatologia Clinica, Università di Firenze, Italy.
Bonaccorsi
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L
Finetti
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G
Luconi
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M
Muratori
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M
Susini
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T
Forti
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G
Serio
M
M
Maggi
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M
D000230:Adenocarcinoma / Q000378:metabolism; D004717:Endometrium / Q000502:physiology*; D005260:Female; D006133:Growth Substances / Q000502:physiology; D006801:Humans; D010972:Platelet Activating Factor / Q000502:physiology*; D014407:Tumor Cells, Cultured; D014594:Uterine Neoplasms / Q000378:metabolism
D006133:Growth Substances; D010972:Platelet Activating Factor