Data from C-C Chemokine Receptor 5 on Pulmonary Mesenchymal Cells Promotes Experimental Metastasis via the Induction of Erythroid Differentiation Regulator 1

Abstract

<div>Abstract<p>C-C Chemokine receptor 5 knockout (<i>Ccr5</i><sup>−/−</sup>) mice develop fewer experimental pulmonary metastases than wild-type (WT) mice. This phenomenon was explored by applying gene expression profiling to the lungs of mice with these metastases. Consequently, erythroid differentiation regulator 1 (<i>Erdr1</i>) was identified as upregulated in the WT mice. Though commonly associated with bone marrow stroma, <i>Erdr1</i> was differentially expressed in WT pulmonary mesenchymal cells (PMC) and murine embryonic fibroblasts (MEF). Moreover, the Ccr5 ligand Ccl4 increased its expression by 3.36 ± 0.14–fold. Ccr5 signaling was dependent on the mitogen-activated protein kinase kinase (Map2k) but not the phosphoinositide 3-kinase (Pi3k) pathway because treatment with U0126 inhibited upregulation of <i>Erdr1</i>, but treatment with LY294002 increased the expression by 3.44 ± 0.92–fold (<i>P</i> < 0.05). The effect <i>Erdr1</i> on B16-F10 melanoma metastasis was verified by the adoptive transfer of WT MEFs into <i>Ccr5</i><sup>−/−</sup> mice. In this model, MEFs that had been transduced with <i>Erdr1</i> short hairpin RNA (shRNA) lowered metastasis by 33% compared with control transduced MEFs. The relevance of ERDR1 on human disease was assessed by coculturing chronic lymphocytic leukemia (CLL) cells with M2-10B4 stromal cells that had been transfected with shRNA or control plasmids. After 96 hours of coculture, the cell counts were higher with control cell lines than with <i>Erdr1</i> knockdown lines [odds ratio (OR), 1.88 ± 0.27, 2.52 ± 0.66, respectively]. This increase was associated with a decrease in apoptotic cells (OR, 0.69 ± 0.18, 0.58 ± 0.12, respectively).</p><p><b>Implications:</b> Therefore, ERDR1 is a stromal-derived factor that promotes cancer cell survival <i>in vitro</i> and in an experimental metastasis model. <i>Mol Cancer Res; 12(2); 274–82. ©2013 AACR</i>.</p></div>