Neutral endopeptidase/CD10 expression during phorbol ester-induced differentiation of choriocarcinoma cells through the protein kinase C- and extracellular signal-regulated kinase-dependent signalling pathway.
Neutral endopeptidase 24.11 (NEP) is identical to CD10, which is a differentiation antigen for early B-lymphoid progenitors in the B-cell differentiation pathway. This ectoenzyme is known to have a key role in the control of growth, differentiation, and signal transduction of many cellular systems by regulating bioactive peptides and cytokines. Recently, we demonstrated that NEP/CD10 is upregulated during forskolin-induced choriocarcinoma cell differentiation, suggesting that NEP/CD10 is a trophoblast differentiation marker. The purpose of this study was to clarify the enhancement of NEP/CD10 expression and its signal transduction pathway during phorbol ester (PMA)-induced differentiation of BeWo choriocarcinoma cells. PMA-induced differentiation of BeWo cells was confirmed by morphological change and human chorionic gonadotropin (hCG) secretion, which was completely blocked by a protein kinase C (PKC) inhibitor, Bisindolylmaleimide I (Bis I). On immunoblot analysis, PMA enhanced NEP/CD10 expression in a dose- and time-dependent manner, which was completely abolished by Bis I and a mitogen-activated protein kinase (MAPK) kinase (MEK) inhibitor, PD98059. PMA also induced phosphorylation of p44/p42 extracellular signal-regulated kinases (ERK) 1 and 2. These observations indicated that activation of PKC by PMA induced differentiation of BeWo cells, and that PMA activated MAPK/ERK, which resulted in the enhancement of NEP/CD10 expression. Furthermore, immunocytochemical analysis showed that NEP/CD10 expression was detected on the membranes of PMA-treated differentiated BeWo cells. In summary, we demonstrated that NEP/CD10 was enhanced during PMA-induced differentiation of BeWo choriocarcinoma cells through a PKC-dependent MEK/ERK signalling pathway. Our findings also suggest that NEP/CD10 may play a functional role in the process of trophoblast differentiation.
Department of Obstetrics and Gynecology, Nagoya University School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
T
T
Suzuki
K
K
Ino
F
F
Kikkawa
C
C
Uehara
H
H
Kajiyama
K
K
Shibata
S
S
Mizutani
D000943:Antigens, Differentiation; D002462:Cell Membrane / Q000201:enzymology; D002471:Cell Transformation, Neoplastic; D002822:Choriocarcinoma / Q000201:enzymology* / Q000473:pathology; D006063:Chorionic Gonadotropin / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D007124:Immunoenzyme Techniques; D007211:Indoles / Q000494:pharmacology; D008301:Maleimides / Q000494:pharmacology; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D015260:Neprilysin / Q000096:biosynthesis*; D010703:Phorbol Esters / Q000494:pharmacology; D010766:Phosphorylation; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D013997:Time Factors; D014407:Tumor Cells, Cultured
D000943:Antigens, Differentiation; D006063:Chorionic Gonadotropin; D004791:Enzyme Inhibitors; D005419:Flavonoids; D007211:Indoles; D008301:Maleimides; D010703:Phorbol Esters; C119222:phorbol-12-myristate; D011493:Protein Kinase C; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D015260:Neprilysin; C070515:bisindolylmaleimide I; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one