Although obesity with associated inflammation is now recognized as a risk factor for breast cancer and distant metastases, the functional basis for these connections remain poorly understood. Here, we show that in breast cancer patients and in animal breast cancer models, obesity is a sufficient cause for increased expression of the bioactive sphingolipid mediator sphingosine-1-phosphate (S1P), which mediates cancer pathogenesis. A high-fat diet was sufficient to upregulate expression of sphingosine kinase 1 (SphK1), the enzyme that produces S1P, along with its receptor S1PR1 in syngeneic and spontaneous breast tumors. Targeting the SphK1/S1P/S1PR1 axis with FTY720/fingolimod attenuated key proinflammatory cytokines, macrophage infiltration, and tumor progression induced by obesity. S1P produced in the lung premetastatic niche by tumor-induced SphK1 increased macrophage recruitment into the lung and induced IL6 and signaling pathways important for lung metastatic colonization. Conversely, FTY720 suppressed IL6, macrophage infiltration, and S1P-mediated signaling pathways in the lung induced by a high-fat diet, and it dramatically reduced formation of metastatic foci. In tumor-bearing mice, FTY720 similarly reduced obesity-related inflammation, S1P signaling, and pulmonary metastasis, thereby prolonging survival. Taken together, our results establish a critical role for circulating S1P produced by tumors and the SphK1/S1P/S1PR1 axis in obesity-related inflammation, formation of lung metastatic niches, and breast cancer metastasis, with potential implications for prevention and treatment. Significance: These findings offer a preclinical proof of concept that signaling by a sphingolipid may be an effective target to prevent obesity-related breast cancer metastasis. Cancer Res; 78(7); 1713–25. ©2018 AACR.

Pancreatic ductal adenocarcinoma (PDAC) is known for its hypovascularity. Bevacizumab, an anti-angiogenic drug, added to standard chemotherapy demonstrated no improvement in outcome for PDAC. Therefore, we hypothesized that increased vascularity may be associated with improved outcomes in PDAC possibly due to better delivery of tumor specific immune cells. To test this hypothesis, PDAC patients were classified into either high or low CD31 expression groups utilizing mRNA expression from RNA-sequence data in The Cancer Genome Atlas (TCGA) pancreatic cancer cohort. High expression of CD31, which indicates presence of more vascular endothelial cells, was associated with significantly better OS (p = 0.002). Multivariate analysis demonstrated that residual tumor (R1, 2; p = 0.026) and CD31 low expression (p = 0.007) were the only independent predictors that negatively impacted OS. Vascular stability as well as immune response related pathways were significantly upregulated in the CD31 high expressing tumors. Furthermore, there were higher proportions of anti-cancer immune cells infiltration, including activated memory CD4+ T cells (p = 0.038), CD8+ T cells (p = 0.027), gamma-delta T cells (p < 0.001) as well as naïve B cells (p = 0.006), whereas lower proportions of regulatory T cell fractions (p = 0.009), which induce an immune tolerant microenvironment, in the CD31 high expressing tumors. These findings imply that stable vessels supply anti-cancer immune cells, which are at least partially responsible for better OS in the CD31 high expressing tumors. In conclusion, CD31 high expressing PDACs have better OS, which may be due to stable vessels that supply anti-cancer immune cells.

Annexin A1 (ANXA1) is a phospholipid-linked protein involved in inflammation, immune response, and mast cell reactivity. Recently, we reported that ANXA1 is associated with aggressive features of triple-negative breast cancer (TNBC); however, its clinical relevance remains controversial. We hypothesized that human TNBC with high expression of ANXA1 mRNA is associated with pro-cancerous immune cell infiltration, including mast cells, and with an aggressive phenotype. Clinical and RNA-seq data were obtained from The Cancer Genome Atlas (TCGA, n = 1079) and Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) (n = 1904). TNBC patients had significantly higher levels of ANXA1 expression compared to the other subtypes in both TCGA and METABRIC cohorts (p < 0.001). ANXA1 protein expression was assessed by immunohistochemistry in Japanese TNBC patient cohort (n = 48), where 17 cases (35.4%) had positive ANXA1 staining, and their overall survival was significantly shorter compared with negative staining group (p = 0.008). The CIBERSORT algorithm was used to calculate immune cell infiltrations. ANXA1 high tumors were associated with activated mast cells and M2 macrophages (p > 0.01), but did not show any association with tumor heterogeneity nor cytolytic activity. High expression of ANXA1 group enriched inflammation, epithelial-to-mesenchymal transition (EMT), and angiogenesis-related genes in a gene set enrichment assay in both cohorts. To our knowledge, this is the first study to demonstrate that ANXA1 is associated with infiltration of mast cells and inflammation that is associated with the aggressive phenotype of TNBC, such as EMT and angiogenesis.

Estrogen receptor (ER) positive breast cancer (BC), the most abundant BC subtype, is notorious for poor response to neoadjuvant chemotherapy (NAC). The androgen receptor (AR) was reported to support estradiol-mediated ER activity in an in vitro system. Recently, ER-positive BC with fewer tumor infiltrating lymphocytes (TILs) was shown to have a better prognosis, opposite to the trend seen with ER-negative BC. We hypothesized that ER-positive BC with high expression of AR will have fewer TILs and an inferior response to NAC, but with a better prognosis. In both TCGA and METABRIC cohorts, AR expression was significantly higher in ER-positive BCs compared to ER-negatives (p < 0.001, p < 0.001, respectively) and it correlated with ER expression (R = 0.630, R = 0.509, respectively). In ER-positive tumors, AR high tumors enriched UV response down (NES = 2.01, p < 0.001), and AR low tumors enriched DNA repair (NES = −2.02, p < 0.001). AR high tumors were significantly associated with procancer regulatory T-cells, and AR low tumors were associated with anticancer immune cells, such as CD4, CD8, and Gamma-Delta T-cells and memory B-cells in ER-positive BC (p < 0.01). Further, cytolytic activity was significantly lower in AR high BC in both cohorts. Finally, AR high tumors had a significantly lower rate of attaining pathological complete response to NAC (GSE22358), but better survival. In conclusion, our results demonstrated that high AR has fewer tumor infiltrating lymphocytes as well as cytolytic activity and an inferior response to NAC, but better survival in ER-positive BC.

There are conflicted experimental results on the role of bone morphogenetic proteins (BMPs) in cancer. Some results suggest that BMPs act as tumor suppressors while other findings indicate that BMPs are oncogenic factors. In the present study, we aimed to investigate the association of BMP expression and the survival of breast cancer patients utilizing The Cancer Genome Atlas (TCGA). High expression levels of BMP1 (P<0.001), BMP3 (P=0.002), BMP5 (P=0.002), BMP7 (P<0.001) and BMPR1A (P<0.001) were associated with better overall survival (OS). On the other hand, high expression levels of BMP6 (P<0.001), BMP8A (P=0.031), BMP8B (P<0.001) and BMPR1B (P=0.005) were associated with worse OS. Most of the BMPs demonstrated differential expression levels between normal and tumor tissues. High expression of BMP7 was found to be significantly associated with better prognosis in both estrogen receptor (ER)‑positive (ER+) (P<0.001) and ER‑negative (ER‑) tumors (P<0.001), whereas high expression of BMP6 was associated with better prognosis only in ER+ tumors (P=0.004); it was associated with worse prognosis in ER‑ tumors (P=0.006). In the ER+ tumors, high expression of BMP7 as well as BMP6 were associated with higher infiltration of anticancer immune cells and cytolytic activity. These results suggest that high expression levels of BMP7 as well as BMP6 possess higher anticancer immunity which results in better prognosis in ER+ breast cancer. In conclusion, BMP expression profiles may be useful for prognostication. Intervention in this pathway may serve to improve outcomes, manage metastatic disease and assist in clinical decision making on optimal therapy based on the risk of recurrence or metastasis.