Age-related alterations in T-lymphocytes modulate key pathways in prostate tumorigenesis.

Background: The primary risk for prostate cancer is aging, often associated with inflammation. Evidence implicates progressive age-related immune dysfunction with increased prostate cancer incidence and mortality. The aged T-cell response is characterized by increased production of pro-inflammatory cytokines, which could significantly contribute to prostate tumorigenesis through induction of key inflammation-mediated pro-survival factors.

Methods: T-cell function of the young (<6 month-old) glycerol-3-phosphate acyltransferase-1 (GPAT-1) knock-out mouse mimics many of the hallmarks observed in an aged (>22-month-old) mouse. Serum and splenic T-lymphocytes from young GPAT-1(-/-) (6 months) and aged wild type (22 months) mice were collected for in vitro studies, including a cytokine immunoarray for serum cytokine levels, luciferase assays for NF-κB activation and Western blot analyses for protein expression.

Results: The T-cell cytokine profile of the GPAT-1(-/-) mice mirrored that observed in aged wild type mice, including higher expression levels of IL-17. Serum- and T-cell-derived factors induced NF-κB activity in normal, non-transformed and prostate cancer epithelial cells, correlating with re-localization of NF-κB and increased protein expression of downstream targets of NF-κB.

Conclusion: The aging and aging-mimic mice produced circulating factors that induce pro-inflammatory pathways in prostate cells, most notably NF-κB. These findings provide evidence that an aged T-cell may directly contribute to the increased risk for prostate cancer in the elderly and establish that the GPAT-1(-/-) model, which mimics many of the characteristics of an aged immune system, is a viable tool for investigating this novel area of cancer risk.