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Prostate. 2001 Mar 1;46(4):319-26.

Long-term exposure of tumor necrosis factor alpha causes hypersensitivity to androgen and anti-androgen withdrawal phenomenon in LNCaP prostate cancer cells.

Author information

1
Department of Urology, University of Occupational & Environmental Health, Kitakyushu, Japan.

Abstract

BACKGROUND:

One of the mechanisms through which prostate cancers relapse during anti-androgen therapy may involve adaptation to low concentrations of androgen induced by anti-androgen therapies. Recent studies from our laboratory have reported that tumor necrosis factor-alpha (TNFalpha) is secreted from prostate cancer epithelial cells and LNCaP cells. We hypothesized that TNFalpha changes androgen-sensitivity in LNCaP cells.

METHODS:

We cultured LNCaP cells for more than 3 months in the presence of 50 ng/ml TNFalpha and established TNFalpha-resistant LNCaP cells (LN-TR2). Sensitivity to androgen was examined by the cell proliferation assay. We also transfected LNCaP and LN-TR2 cells with a luciferase reporter plasmid driven by prostate-specific antigen (PSA) promoter and compared PSA promoter activity. Nuclear localization of AR protein that binds to target genes was also examined by Western blotting.

RESULTS:

LN-TR2 cells had increased sensitivity to dihydrotestosterone (DHT) (i.e., proliferation and PSA promoter activation) than LNCaP cells. Total AR mRNA and AR protein levels were decreased in LN-TR2 cells. However, LN-TR2 cells demonstrated increased levels of nuclear AR compared to LNCaP cells. At 1 nM DHT, the anti-androgen bicalutamide stimulated LN-TR2 and inhibited LNCaP proliferation.

CONCLUSIONS:

Long-term exposure of TNFalpha causes hypersensitivity to DHT in LNCaP and this was associated with increased nuclear AR protein. Furthermore, hypersensitivity to androgen caused anti-androgen withdrawal phenomenon in the presence of DHT although bicalutamide itself did not stimulate LNCaP proliferation without androgen. This result may be one possible mechanism for the anti-androgen withdrawal phenomenon.

PMID:
11241555
[Indexed for MEDLINE]

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