Pten null prostate epithelium promotes localized myeloid-derived suppressor cell expansion and immune suppression during tumor initiation and progression [microdissected tissue]

ABSTRACT: Chronic inflammation is known to associate with prostate cancer development, but how epithelium-associated cancer initiating events cross-talk to inflammatory cells during prostate cancer initiation and progression is largely unknown. Using the Pten null murine prostate cancer model, we show an expansion of Gr-1+CD11b+ myeloid-derived suppressor cells (MDSCs) occurring intra-prostatically immediately following epithelium-specific Pten deletion without expansion in hematopoietic tissues. This MDSC expansion is accompanied by sustained immune suppression. Prostatic Gr-1+CD11b+ cells, but not those isolated from the spleen of the same tumor bearing mice, suppress T cell proliferation and express high levels of Arginase 1 and iNOS. Mechanistically, loss of PTEN in the epithelium leads to a significant upregulation of genes within the inflammatory response and cytokine-cytokine receptor interaction pathways, including Csf-1 and IL-1β, two genes known to induce MDSC expansion and immunosuppressive activities. Treating Pten null mice with the selective CSF-1 receptor inhibitor GW2580 decreases MDSC infiltration and relieves the associated immunosuppressive phenotype. Our study indicates that epithelium-associated tumor initiating events trigger the secretion of inflammatory cytokines and promote localized MDSC expansion and immune suppression, thereby promoting tumor progression. Laser-capture microdissection was used to extract epithelial cells from murine benign and Pten null prostate tumors. Their transcript levels were measured by the custom Agilent 4x44K whole mouse genome expression oligonucleotide microarrays. Each cohort had three biological replicates.

ORGANISM(S): Mus musculus

SUBMITTER: Linh Tran 

PROVIDER: E-GEOD-56469 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress