The Calcineurin-NFAT-Angiopoietin 2 signaling axis in lung endothelium is critical for the establishment of lung metastases

The pre-metastatic niche is a pre-determined site of metastases, awaiting the influx of tumor cells. Here we demonstrate that the calcineurin-NFAT pathway is activated specifically in lung endothelium prior to the detection of tumor cells that preferentially metastasize to the lung. We previously showed that DSCR-1 functions in a negative feedback loop to attenuate calcineurin signaling. Upregulation of the calcineurin pathway via loss of Dscr-1 leads to a significant increase in lung metastasis due to the increased expression of a newly identified NFAT target, Angiopoietin (Ang)-2. An increase in VEGF levels specifically in the lung versus other organ microenvironments triggers a threshold of calcineurin-NFAT signaling that transactivates Ang2 in lung endothelium. Further, we demonstrate that overexpression of DSCR-1 or the Ang-2 receptor, soluble Tie2, prevents activation of the lung endothelium inhibiting lung metastases in our mouse models. Our studies provide insights into mechanisms underlying angiogenesis in the pre-metastatic niche and offers novel targets for lung metastases.

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Minami T, Jiang S, Schadler K, Suehiro J, Osawa T, Oike Y, Miura M, Naito M, Kodama T, Ryeom S