The survival effect of prolactin on PC3 prostate cancer cells.
OBJECTIVE
Recent studies suggest a paracrine/autocrine loop involving prolactin (PRL) within the human prostate. The aims of this study were to determine the effects of PRL on the growth and survival of prostate cancer cells and the intracellular signalling mechanisms underlying such effects.


METHODS
The effect of PRL on proliferation of LNCaP, PC3 and DU145 was assessed by Coulter counting. The effect of PRL on TRAIL-, staurosporine- and flavopiridol-induced apoptosis was assessed by Timelapse microscopy and Annexin V binding. The status of the PRL receptor (PRL-R) and Akt/PKB (protein kinase B) activity were assessed by Western blotting.


RESULTS
All three cell lines expressed both the short and long forms of the PRL receptor. Although, no significant effect of PRL on the proliferation of these cells was found, PRL partially inhibited TRAIL-induced apoptosis in PC3 cells. PRL also enhanced the phosphorylation of Akt/PKB in these cells.


CONCLUSIONS
PRL had no significant effect on the proliferation of PC3, DU145 and LNCaP, but inhibited TRAIL-induced apoptosis in PC3 cells, possibly via enhanced Akt/PKB phosphorylation in PC3 cells. Further investigations are underway to determine the survival effect of PRL on the other two prostate cancer cell line.
Ruffion
Alain
A
Department of Urology, Hopital Jules Courmont, Chemin du Grand Revoyet, 69495 Pierre Bénite Cedex, France. alain.ruffion@wanadoo.fr
Al-Sakkaf
Kaltoom A
KA
Brown
Barry L
BL
Eaton
Colby L
CL
Hamdy
Freddie C
FC
Dobson
Pauline R M
PR
D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D006801:Humans; D008297:Male; D011388:Prolactin / Q000494:pharmacology*; D011471:Prostatic Neoplasms / Q000378:metabolism* / Q000473:pathology*; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins / Q000187:drug effects; D051057:Proto-Oncogene Proteins c-akt; D011981:Receptors, Prolactin / Q000187:drug effects; D015398:Signal Transduction / Q000187:drug effects*; D014407:Tumor Cells, Cultured / Q000187:drug effects
D011518:Proto-Oncogene Proteins; D011981:Receptors, Prolactin; D011388:Prolactin; C494918:AKT1 protein, human; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt