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Interleukin-6 Increases Expression And Secretion Of Cathepsin B By Breast Tumor-Associated Monocytes., Mona M. Mohamed, Dora Cavallo-Medved, Deborah Rudy, Arulselvi Anbalagan, Bonnie F. Sloane, Kamir Moin

Biological Sciences Publications

In the tumor microenvironment, monocytes respond to paracrine stimuli from breast cancer cells by secreting molecules that participate in breast cancer growth, invasion, intravasation and metastasis. Here we examined the effects of media conditioned by MDA-MB-231 human breast carcinoma cells (231-CM) on expression and secretion of proteases and secretion of cytokines by U937 human monocytes. We found that 231-CM increased U937: 1) proliferation; 2) expression, activity and secretion of the cysteine protease cathepsin B (CTSB); 3) secretion of matrix metalloproteinases (MMP)-2 and -9; and 4) secretion of interleukin-6 (IL-6) and insulin-like growth factor binding protein-1 (IGFBP-1). We further demonstrated by …