Norepinephrine activates P44 and P42 MAPK in human prostate stromal and smooth muscle cells but not in epithelial cells.
BACKGROUND
In vascular smooth muscle cells, alpha1-adrenergic stimulation increases DNA synthesis and cell proliferation via activation of p44/42 (ERK1/2) MAPK. We examined whether norepinephrine (NE) activates MAPK and stimulates the proliferation of prostatic epithelial and non-epithelial cells.


METHODS
Human prostatic epithelial cells, stromal cells, and smooth muscle cells were purchased from BioWhittaker (Walkersville, MD). After reaching a semi-confluent condition, the cells were cultured in RPMI-1640 without serum for 1 day. At 10 min after adding NE (10(-6) or 10(-7) M) to the medium, the cells were collected. Cell lysate was analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) followed by Western blot using anti-phospho-p44/42 and anti-p44/42 antibodies. The activation of p44/42 was estimated by the ratio of phospho-p44/42 to total p44/42. Cell proliferation was evaluated by (3)H-thymidine uptake assay. After reaching a semi-confluent condition, the cells were cultured in RPMI-1640 containing 0.5% FCS with or without NE (10(-6) or 10(-7) M) for 16 hr followed by a (3)H-thymidine uptake period (24 hr).


RESULTS
P44/42 MAPK was significantly activated by NE in non-epithelial cells (stromal cells and smooth muscle cells) while not in epithelial cells. The uptake of (3)H-thymidine was significantly increased by NE in both non-epithelial cells, which was inhibited by alpha1-adrenoceptor antagonists.


CONCLUSIONS
These results suggest that NE may stimulate the proliferation of non-epithelial prostatic cells, which may be involved in the pathogenesis of BPH.
Kanagawa
Kenji
K
Department of Urology, Osaka City University Medical School, Osaka, Japan.
Sugimura
Kazunobu
K
Kuratsukuri
Katsuyuki
K
Ikemoto
Shin-Ichi
S
Kishimoto
Taketoshi
T
Nakatani
Tatsuya
T
D015153:Blotting, Western; D018929:Cell Culture Techniques; D002455:Cell Division / Q000502:physiology*; D004847:Epithelial Cells / Q000502:physiology; D006801:Humans; D008297:Male; D019950:Mitogen-Activated Protein Kinase 1 / Q000096:biosynthesis*; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000096:biosynthesis*; D032389:Myocytes, Smooth Muscle / Q000502:physiology; D009638:Norepinephrine / Q000494:pharmacology*; D011467:Prostate / Q000166:cytology* / Q000502:physiology*; D017154:Stromal Cells / Q000502:physiology; D013936:Thymidine
D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D013936:Thymidine; D009638:Norepinephrine