S100A4 Elevation Empowers Expression of Metastasis Effector Molecules in Human Breast Cancer.

Many human glandular cancers metastasize along nerve tracts, but the mechanisms involved are generally poorly understood. The calcium-binding protein S100A4 is expressed at elevated levels in human cancers, where it has been linked to increased invasion and metastasis. Here we report genetic studies in a Drosophila model to define S100A4 effector functions that mediate metastatic dissemination of mutant Ras-induced tumors in the developing nervous system. In flies overexpressing mutant RasVal12 and S100A4, there was a significant increase in activation of the stress kinase JNK and production of the matrix metalloproteinase MMP1. Genetic or chemical blockades of JNK and MMP1 suppressed metastatic dissemination associated with S100A4 elevation, defining required signaling pathway(s) for S100A4 in this setting. In clinical specimens of human breast cancer, elevated levels of the mammalian paralogs MMP2, MMP9, and MMP13 are associated with a 4- to 9-fold relative decrease in patient survival. In individual tumors, levels of MMP2 and MMP13 correlated more closely with levels of S100A4, whereas MMP9 levels correlated more closely with the S100 family member S100P. Overall, our results suggest the existence of evolutionarily conserved pathways used by S100A4 to promote metastatic dissemination, with potential prognostic and therapeutic implications for metastasis by cancers that preferentially exploit nerve tract migration routes. Cancer Res; 77(3); 780-9. ©2016 AACR.

Significance of the Fanconi anemia FANCD2 protein in sporadic and metastatic human breast cancer.

FANCD2, a pivotal protein in the Fanconi anemia and BRCA pathway/network, is monoubiquitylated in the nucleus in response to DNA damage. This study examines the subcellular location and relationship with prognostic factors and patient survival of FANCD2 in breast cancer. Antibodies to FANCD2 were used to immunocytochemically stain 16 benign and 20 malignant breast specimens as well as 314 primary breast carcinomas to assess its association with subcellular compartment and prognostic factors using Fisher's Exact test or with patient survival over 20 years using Wilcoxon-Gehan statistics. Immunoreactive FANCD2 was found in the nucleus and cytoplasm of all 16 benign tissues, but nuclear staining was lost from a significant 19/20 malignant carcinomas (P < 0.0001). Antibodies to FANCD2 stained the cytoplasm of 196 primary carcinomas, leaving 118 as negatively stained. Negative cytoplasmic staining was significantly associated with positive staining for the metastasis-inducing proteins S100A4, S100P, osteopontin, and AGR2 (P < or = 0.002). Survival of patients with FANCD2-negative carcinomas was significantly worse (P < 0.0001) than those with positively stained carcinomas, and only 4% were alive at the census date. Multivariate regression analysis identified negative staining for cytoplasmic FANCD2 as the most significant indicator of patient death (P = 0.001). Thus FANCD2's cytoplasmic loss in the primary carcinomas may allow the selection of cells overexpressing proteins that can induce metastases before surgery.