The Aged Microenvironment Enhances the Tumorigenic Potential of Malignant Prostate Epithelial Cells

The incidence of prostate cancer is directly linked to age, but we still lack an adequate understanding of the prostatic aging-associated changes that facilitate carcinogenesis. In this study, we investigated possible associated factors in the aged prostate microenvironment, using an orthotopic mouse model of prostate cancer. We found that aged mice showed accelerated growth of TRAMP-C2 cells, compared with young mice. Metastatic lesions following intravenous injection were also more numerous in aged mice. TRAMP-C2 tumors from young and aged mice showed no significant differences concerning their proliferation index, apoptosis or angiogenesis. However, analysis of tumor-infiltrating immune cells by immunohistochemistry and RNA-seq gene expression revealed that aged mice present higher numbers of macrophages in normal prostatic tissue and that these are quickly polarized towards an M2 phenotype upon TRAMP-C2 cells engraftment. RNA sequencing of TRAMP-C2 tumors from young and aged mice using the Illumina TruSeq Stranded mRNA LT library kit and sequenced on Illumina HiSeq 2500.