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Prostate. 2008 Nov 1;68(15):1647-54. doi: 10.1002/pros.20829.

Oligomeric proanthocyanidin complexes (OPC) exert anti-proliferative and pro-apoptotic effects on prostate cancer cells.

Author information

1
Department of Urology, Innsbruck Medical University, Innsbruck, Austria.

Abstract

BACKGROUND:

Oligomeric proanthocyanidin complexes (OPC) are extracted from grape seeds or maritime pine bark and have been used for enhancement of capillary stability and lymphatic drainage. Since a role for OPC in cancer prevention was postulated, we asked whether they have an effect on prostate cancer cells.

METHODS:

Cell proliferation was determined by (3)H-thymidine assay and cell cycle status was analyzed on a flow cytometer. Expression of regulators of proliferation and apoptosis was determined by Western blot.

RESULTS:

We found that androgen-responsive cells LNCaP are more sensitive to OPC in terms of inhibition of proliferation in comparison to androgen receptor-negative PC3 or DU145 cells. Treatment with OPC resulted in a decrease in the percentage of LNCaP cells in the S phase and an increase in the percentage of cells in sub G1 phase. The anti-proliferative and pro-apoptotic effect of OPC in the LNCaP cell line was associated with down-regulation of expression of the androgen receptor. Interestingly, similar regulatory effects of OPC, such as inhibition of expression of cyclin-dependent kinases and cyclins and stimulation of tumor suppressors p21 and p27, were seen in LNCaP and PC3 cells. Favorable changes in the Bcl-2/Bax ratio were observed in LNCaP and PC3 cells after the treatment with OPC. OPC caused an increase of phosphorylated mitogen-activated protein kinase p44 and p42, thus suggesting induction of cellular differentiation.

CONCLUSIONS:

We conclude that OPC is a candidate that fulfills criteria for chemopreventive strategies in prostate cancer that might be established in following in vivo studies.

PMID:
18663730
DOI:
10.1002/pros.20829
[Indexed for MEDLINE]

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