Tai Yu-Tzu, Podar Klaus, Mitsiades Nicholas, Lin Boris, Mitsiades Constantine, Gupta Deepak, Akiyama Masaharu, Catley Laurence, Hideshima Teru, Munshi Nikhil C, Treon Steven P, Anderson Kenneth C
Jerome Lipper Multiple Myeloma Center, Department of Adult Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA.
Blood. 2003 Apr 1;101(7):2762-9. doi: 10.1182/blood-2002-09-2813. Epub 2002 Nov 14.
Multiple myeloma (MM) is characterized by clonal expansion of malignant plasma cells in the bone marrow and their egress into peripheral blood with progression to plasma cell leukemia. Our previous study defined a functional role of CD40 activation in MM cell homing and migration. In this study, we examine signaling events mediating CD40-induced MM cell migration. We show that cross-linking CD40, using either soluble CD40L (sCD40L) or anti-CD40 monoclonal antibody (mAb), induces phosphatidylinositol 3-kinase (PI3K) activity and activates its downstream effector AKT in MM.1S cells. CD40 activation also activates the MAP kinase (MEK) pathway, evidenced by phosphorylation of extracellular signal-regulated mitogen-activated protein kinase (ERK), but not c-jun amino-terminal kinase (JNK) or p38, in a dose- and time-dependent manner. Using pharmacologic inhibitors of PI3K and MEK, as well as adenoviruses expressing dominant-negative and constitutively expressed AKT, we demonstrate that PI3K and AKT activities are required for CD40-induced MM cell migration. In contrast, inhibition of ERK/MEK phosphorylation only partially (10%-15%) prevents migration, suggesting only a minor role in regulation of CD40-mediated MM migration. We further demonstrate that CD40 induces nuclear factor (NF)-kappa B activation as a downstream target of PI3K/AKT signaling, and that inhibition of NF-kappa B signaling using specific inhibitors PS1145 and SN50 completely abrogates CD40-induced MM migration. Finally, we demonstrate that urokinase plasminogen activator (uPA), an NF-kappa B target gene, is induced by CD40; and conversely, that uPA induction via CD40 is blocked by PI3K and NF-kappa B inhibitors. Our data therefore indicate that CD40-induced MM cell migration is primarily mediated via activation of PI3K/AKT/NF-kappa B signaling, and further suggest that novel therapies targeting this pathway may inhibit MM cell migration associated with progressive MM.
多发性骨髓瘤（MM）的特征是骨髓中恶性浆细胞的克隆性扩增，随着病情进展至浆细胞白血病，这些细胞会进入外周血。我们之前的研究确定了CD40激活在MM细胞归巢和迁移中的功能作用。在本研究中，我们研究介导CD40诱导的MM细胞迁移的信号事件。我们发现，使用可溶性CD40配体（sCD40L）或抗CD40单克隆抗体（mAb）交联CD40，可诱导磷脂酰肌醇3激酶（PI3K）活性并激活其下游效应物AKT在MM.1S细胞中。CD40激活还激活丝裂原活化蛋白激酶（MEK）途径，表现为细胞外信号调节的丝裂原活化蛋白激酶（ERK）磷酸化，但不包括c-jun氨基末端激酶（JNK）或p38，呈剂量和时间依赖性。使用PI3K和MEK的药理抑制剂，以及表达显性负性和组成性表达AKT的腺病毒，我们证明PI3K和AKT活性是CD40诱导的MM细胞迁移所必需的。相比之下，抑制ERK/MEK磷酸化仅部分（10%-15%）阻止迁移，表明其在调节CD40介导的MM迁移中仅起次要作用。我们进一步证明CD40诱导核因子（NF）-κB激活作为PI3K/AKT信号的下游靶点，并且使用特异性抑制剂PS1145和SN50抑制NF-κB信号完全消除CD40诱导的MM迁移。最后，我们证明尿激酶型纤溶酶原激活剂（uPA），一种NF-κB靶基因，由CD40诱导；相反，通过CD40诱导uPA被PI3K和NF-κB抑制剂阻断。因此，我们的数据表明CD40诱导的MM细胞迁移主要通过PI3K/AKT/NF-κB信号激活介导，并且进一步表明靶向该途径的新型疗法可能抑制与进展性MM相关的MM细胞迁移。
