Interleukin 1beta mediates the modulatory effects of monocytes on LNCaP human prostate cancer cells.
Proliferative and secretory responses in androgen-sensitive prostate cancer LNCaP cells are regulated by steroid and peptide hormones and by differentiation-promoting substances. In the present study, we evaluated whether peripheral blood monocytes that exhibit anti-tumour activity in haematopoietic and solid tumours influence growth and secretion in the LNCaP cell line. For this purpose, LNCaP cells were incubated with monocyte-conditioned medium (MCM), and proliferation as well as expression of androgen receptor (AR) and secretion of prostate-specific antigen (PSA) were assessed. Conditioned medium from monocytes reduced proliferation in a dose-dependent manner. Incubation with 40% MCM caused a 50% reduction in cell proliferation. AR protein decreased by 70% and PSA levels in supernatants from LNCaP cells were reduced by approximately 80% following treatment with MCM. We focused on the contribution of two major products of activated monocytes, prostaglandin E2 and interleukin 1beta (IL-1beta), to the MCM modulatory action. LNCaP cells treated with prostaglandin E2 showed neither a reduction in proliferation nor a down-regulation of AR and PSA levels. The effects of MCM on cellular proliferation, AR protein and PSA secretion were abolished by pretreatment of MCM with a neutralizing anti-IL-1beta antibody. In addition, recombinant IL-1beta was able to replace MCM for the inhibition of proliferation and down-regulation of AR and PSA proteins. LNCaP cells were shown to express the IL-1beta receptor type 1, which transduces IL-1beta signal. Our findings reveal that monocyte-derived IL-1beta inhibits the proliferation of androgen-responsive prostate tumour cells and reduces AR and PSA levels.
Culig
Z
Z
Department of Urology, University of Innsbruck, Austria.
Hobisch
A
A
Herold
M
M
Hittmair
A
A
Thurnher
M
M
Eder
I E
IE
Cronauer
M V
MV
Rieser
C
C
Ramoner
R
R
Bartsch
G
G
Klocker
H
H
Konwalinka
G
G
D002455:Cell Division; D048429:Cell Size; D017077:Culture Media, Conditioned; D015232:Dinoprostone / Q000502:physiology; D006801:Humans; D007375:Interleukin-1 / Q000502:physiology*; D008297:Male; D009000:Monocytes / Q000276:immunology*; D017430:Prostate-Specific Antigen / Q000378:metabolism*; D011471:Prostatic Neoplasms / Q000276:immunology*; D011944:Receptors, Androgen / Q000378:metabolism; D014407:Tumor Cells, Cultured
D017077:Culture Media, Conditioned; D007375:Interleukin-1; D011944:Receptors, Androgen; D017430:Prostate-Specific Antigen; D015232:Dinoprostone