TMPRSS2-ERG Fusion Promotes Recruitment of Regulatory T cells and Tumor Growth in Prostate Cancer.

BACKGROUND: This study was designed to examine the effect of transmembrane protease serine 2 ETS-related gene (TMPRSS2-ERG) fusion on regulatory T cells and tumor growth in prostate cancer, which may provide a new potential therapeutic direction for PCa. METHODS: The effect of TMPRSS2-ERG fusion on the migration of Treg cells and tumor growth in a mouse model was investigated in vitro and in vivo. TMPRSS2-ERG fusion in biopsy tissues was performed by fluorescence in situ hybridization and the expression of ERG and Forkhead box P3 was detected by gel electrophoresis, real-time quantitative reverse transcription polymerase chain reaction and Western blot. Enzyme-linked immunosorbent assay and flow cytometry were used to analyze transforming growth factor ß levels and the number of regulatory T cells, respectively. Finally, the infiltration of regulatory T cells was analyzed by Forkhead box P3 immunohistochemistry. RESULTS: Fluorescence in situ hybridization analysis showed that the TMPRSS2-ERG fusion gene was positive in prostate cancer and that the messenger RNA and protein expression of ERG were significantly up-regulated in prostate cancer biopsy tissues. Furthermore, the number of regulatory T cells and the levels of Forkhead box P3 and transforming growth factor ß were significantly increased in prostate cancer. TMPRSS2-ERG fusion increased the migration and activation of regulatory T cells in vitro and promoted subcutaneous tumor size and regulatory T cells infiltration in mouse models. CONCLUSIONS: TMPRSS2-ERG fusion can regulate the recruitment and infiltration of regulatory T cells to promote tumor growth in prostate cancer.

Multiplexed single molecule immunoassays.

We have developed a method that enables the multiplexed detection of proteins based on counting single molecules. Paramagnetic beads were labeled with fluorescent dyes to create optically distinct subpopulations of beads, and antibodies to specific proteins were then immobilized to individual subpopulations. Mixtures of subpopulations of beads were then incubated with a sample, and specific proteins were captured on their specific beads; these proteins were then labeled with enzymes via immunocomplex formation. The beads were suspended in enzyme substrate, loaded into arrays of femtoliter wells--or Single Molecule Arrays (Simoa)--that were integrated into a microfluidic device (the Simoa disc). The wells were then sealed with oil, and imaged fluorescently to determine: a) the location and subpopulation identity of individual beads in the femtoliter wells, and b) the presence or absence of a single enzyme associated with each bead. The images were analyzed to determine the average enzyme per bead (AEB) for each bead subpopulation that provide a quantitative parameter for determining the concentration of each protein. We used this approach to simultaneously detect TNF-α, IL-6, IL-1α, and IL-1ß in human plasma with single molecule resolution at subfemtomolar concentrations, i.e., 200- to 1000-fold more sensitive than current multiplexed immunoassays. The simultaneous, specific, and sensitive measurement of several proteins using multiplexed digital ELISA could enable more reliable diagnoses of disease.