Secretion of a soluble T cell promoting factor by the human prostate adenocarcinoma cell line DU-145.
BACKGROUND
A variety of cancers suppress host immune defenses by secretion of soluble factors. Conditioned media (CM) from numerous cancer cell lines possess the ability to suppress proliferation of activated T cells. The effects of CM from the prostate cancer cell line DU-145 on T cell activation was investigated.


METHODS
Human PBMC, purified T cells and Jurkat T cells were treated with DU-145 CM. Proliferation, cell cycle, apoptosis, Fas expression/and cytokine secretion were assessed by thymidine incorporation, flow cytometry and ELISA.


RESULTS
DU-145 CM increased proliferation of concanavalin-A (ConA) activated peripheral blood mononuclear cells (PBMC) increasing the percentage of cells in the S/G2 phase of cell cycle. Treatment of the Jurkat T cell line with DU-145 CM induced a potent proliferative response. ConA-induced proliferation of purified T cells from human PBMC and murine splenocytes was augmented in a dose-dependent manner by addition of DU- 145 CM. DU- 145 CM treatment of ConA-activated T cells induced an increase in interleukin-2 (IL-2) production. The soluble factor(s) responsible for promoting T cell proliferation was dependent on protein synthesis by the DU- 145 cells and possessed a molecular weight greater than 10 kDa.


CONCLUSIONS
DU- 145 cells secrete a soluble factor(s) > 10 kDa, whose production is dependent on protein synthesis and which acts as a promoter of T cell activation.
Zhong
Z
Z
Department of Surgery, Division of Urology, University of Western Ontario, London Ontario, Canada.
Onita
T
T
Kusznieruk
K P
KP
Ren
L
L
Chin
J
J
D000230:Adenocarcinoma / Q000276:immunology* / Q000378:metabolism; D017209:Apoptosis; D002455:Cell Division; D017077:Culture Media, Conditioned; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism; D007376:Interleukin-2 / Q000378:metabolism; D019169:Jurkat Cells; D008213:Lymphocyte Activation; D008297:Male; D011471:Prostatic Neoplasms / Q000276:immunology* / Q000378:metabolism; D014176:Protein Biosynthesis; D012995:Solubility; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism*; D014407:Tumor Cells, Cultured; D019014:fas Receptor / Q000378:metabolism
D017077:Culture Media, Conditioned; D007376:Interleukin-2; D019014:fas Receptor; D007371:Interferon-gamma