Metastasis portends a poor prognosis for cancer patients. Primary tumor cells disseminate through the bloodstream before the appearance of detectable metastatic lesions. The analysis of cancer cells in blood-so-called circulating tumor cells (CTCs)-may provide unprecedented opportunities for metastatic risk assessment and investigation. NanoFlares are nanoconstructs that enable livecell detection of intracellular mRNA. NanoFlares, when coupled with flow cytometry, can be used to fluorescently detect genetic markers of CTCs in the context of whole blood. They allow one to detect as few as 100 live cancer cells per mL of blood and subsequently culture those cells. This technique can also be used to detect CTCs in a murine model of metastatic breast cancer. As such, NanoFlares provide, to our knowledge, the first genetic-based approach for detecting, isolating, and characterizing live cancer cells from blood and may provide new opportunities for cancer diagnosis, prognosis, and personalized therapy.cancer metastasis | nanotechnology | diagnostic | mRNA | NanoFlares

Purpose: Basal-like breast tumors are typically (ER/PR/HER2) triple-negative and are associated with a high incidence of brain metastases and poor clinical outcomes. The molecular chaperone aB-crystallin is predominantly expressed in triple-negative breast cancer (TNBC) and contributes to an aggressive tumor phenotype in preclinical models. We investigated the potential role of aB-crystallin in brain metastasis in TNBCs.Experimental Design: aB-crystallin expression in primary breast carcinomas and brain metastases was analyzed by immunohistochemistry among patients with breast cancer with brain metastases. aB-crystallin was overexpressed or silenced in two different TNBC cell lines. The effects on cell adhesion to human brain microvascular endothelial cells (HBMEC) or extracellular matrix proteins, transendothelial migration, and transmigration across a HBMEC/astrocyte coculture blood-brain barrier (BBB) model were examined. In addition, the effects of overexpressing or silencing aB-crystallin on brain metastasis in vivo were investigated using orthotopic TNBC models.Results: In a cohort of women with breast cancer brain metastasis, aB-crystallin expression in primary breast carcinomas was associated with poor overall survival and poor survival after brain metastasis, even among patients with TNBC. Stable overexpression of aB-crystallin in TNBC cells enhanced adhesion to HBMECs, transendothelial migration, and BBB transmigration in vitro, whereas silencing aB-crystallin inhibited these events. aB-crystallin promoted adhesion of TNBC cells to HBMECs, at least in part, through an a3b1 integrin-dependent mechanism. aB-crystallin overexpression promoted brain metastasis, whereas silencing aB-crystallin inhibited brain metastasis in orthotopic TNBC models.Conclusion: aB-crystallin is a novel regulator of brain metastasis in TNBC and represents a potential biomarker and drug target for this aggressive disease. Clin Cancer Res; 1-12. Ó2013 AACR.