Project description:S100A10 (p11) is a plasminogen receptor that regulatess cellular plasmin generation by cancer cells. In the current study we used the MMTV-PyMT mouse breast cancer model to investigate the role of p11 in oncogenesis. Genetic deletion of p11 resulted in significantly decreased tumor onset, growth rate and spontaneous pulmonary metastatic burden in the PyMT/p11-KO mice. This phenotype was accompanied by substantial reduction in Ki67 positivity, macrophage infiltration and decreased vascular density in the primary tumors, and appearance of invasive carcinoma and pulmonary metastasis. Surprisingly, immunohistochemical analysis of wild-type MMTV-PyMT mice failed to detect p11 expression in the tumors or metastatic tumor cells and loss of p11 did not decrease plasmin generation in the PyMT tumors and cells. Furthermore, tumor cells expressing p11 displayed dramatically reduced lung metastasis when injected into p11-depleted mice, further strengthening the stromal role of p11. Transcriptome analysis of the p11-depleted tumors showed marked reduction in genes involved in breast cancer development, progression, and inflammation such as AREG, MUC1 and S100A8. The PyMT/p11-KO tumors displayed remarkable increase in inflammatory cytokines such as IL-6, IL-10 and IFN-γ. Gene expression profiling and immunohistochemistry primary breast cancer samples showed that p11 mRNA and protein was significantly higher in tumors compared to normal mammary tissue. The mRNA expression was significantly associated with poor patient prognosis and significantly elevated in high grade, triple negative tumors and tumors with high proliferative index. We used microarray to detail the global programme of gene expression underlying reduced growth/establishment of P11-KO PyMT tumours.
