Increased levels of the calcium‐binding protein neuronal calcium sensor 1 (NCS1) predict an unfavorable patient outcome in several aggressive cancers, including breast and liver tumors. Previous studies suggest that NCS1 overexpression facilitates metastatic spread of these cancers. To investigate this hypothesis, we explored the effects of NCS1 overexpression on cell proliferation, survival, and migration patterns in vitro in 2‐ and 3‐dimensional (2/3‐D). Furthermore, we translated our results into an in vivo mouse xenograft model. Cell‐based proliferation assays were used to demonstrate the effects of overexpression of NCS1 on growth rates. In vitro colony formation and wound healing experiments were performed and 3‐D migration dynamics were studied using collagen gels. Nude mice were injected with breast cancer cells to monitor NCS1‐dependent metastasis formation over time. We observed that increased NCS1 levels do not change cellular growth rates, but do significantly increase 2‐ and 3‐D migration dynamics in vitro. Likewise, NCS1‐overexpressing cells have an increased capacity to form distant metastases and demonstrate better survival and less necrosis in vivo. We found that NCS1 preferentially localizes to the leading edge of cells and overexpression increases the motility of cancer cells. Furthermore, this phenotype is correlated with an increased number of metastases in a xenograft model. These results lay the foundation for exploring the relevance of an NCS1‐mediated pathway as a metastatic biomarker and as a target for pharmacologic interventions.—Apasu, J. E., Schuette, D., LaRanger, R., Steinle, J. A., Nguyen, L. D., Grosshans, H. K., Zhang, M., Cai, W. L., Yan, Q., Robert, M. E., Mak, M., Ehrlich, B. E. Neuronal calcium sensor 1 (NCS1) promotes motility and metastatic spread of breast cancer cells in vitro and in vivo. FASEB J. 33, 4802–4813 (2019). http://www.fasebj.org

Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related death worldwide. There is an urgent demand for prognostic biomarkers that facilitate early tumor detection, as the incidence of HCC has tripled in the United States in the last three decades. Biomarkers to identify populations at risk would have significant impact on survival. We recently found that expression of Neuronal Calcium Sensor 1 (NCS1), a Ca2-dependent signaling molecule, predicted disease outcome in breast cancer, but its predictive value in other cancer types is unknown. This protein is potentially useful because increased NCS1 regulates Ca2 signaling and increased Ca2 signaling is a hallmark of metastatic cancers, conferring cellular motility and an increasingly aggressive phenotype to tumors. We explored the relationship between NCS1 expression levels and patient survival in two publicly available liver cancer cohorts and a tumor microarray using data mining strategies. High NCS1 expression levels are significantly associated with worse disease outcome in Asian patients within these cohorts. In addition, a variety of Ca2-dependent and tumor growth-promoting genes are transcriptionally coregulated with NCS1 and many of them are involved in cytoskeleton organization, suggesting that NCS1 induced dysregulated Ca2 signaling facilitates cellular motility and metastasis. We found NCS1 to be a novel biomarker in HCC. Furthermore, our study identified a pharmacologically targetable signaling complex that can influence tumor progression in HCC. These results lay the foundation for using NCS1 as a prognostic biomarker in prospective cohorts of HCC patients and for further functional assessment of the characterized signaling axis. .