多发性骨髓瘤来源的外泌体富含 Amphiregulin（AREG），并在骨微环境中激活表皮生长因子途径，导致破骨细胞生成。
Multiple myeloma-derived exosomes are enriched of amphiregulin (AREG) and activate the epidermal growth factor pathway in the bone microenvironment leading to osteoclastogenesis.
机构信息
Department of Biopathology and Medical Biotechnologies (Di.Bi.Med.), University of Palermo, Palermo, Italy.
Department of Medicine and Surgery, University of Parma, Parma, Italy.
出版信息
J Hematol Oncol. 2019 Jan 8;12(1):2. doi: 10.1186/s13045-018-0689-y.
BACKGROUND
Multiple myeloma (MM) is a clonal plasma cell malignancy associated with osteolytic bone disease. Recently, the role of MM-derived exosomes in the osteoclastogenesis has been demonstrated although the underlying mechanism is still unknown. Since exosomes-derived epidermal growth factor receptor ligands (EGFR) are involved in tumor-associated osteolysis, we hypothesize that the EGFR ligand amphiregulin (AREG) can be delivered by MM-derived exosomes and participate in MM-induced osteoclastogenesis.
METHODS
Exosomes were isolated from the conditioned medium of MM1.S cell line and from bone marrow (BM) plasma samples of MM patients. The murine cell line RAW264.7 and primary human CD14 cells were used as osteoclast (OC) sources.
RESULTS
We found that AREG was specifically enriched in exosomes from MM samples and that exosomes-derived AREG led to the activation of EGFR in pre-OC, as showed by the increase of mRNA expression of its downstream SNAIL in both RAW264.7 and CD14 cells. The presence of neutralizing anti-AREG monoclonal antibody (mAb) reverted this effect. Consequently, we showed that the effect of MM-derived exosomes on osteoclast differentiation was inhibited by the pre-treatment of exosomes with anti-AREG mAb. In addition, we demonstrated the ability of MM-derived AREG-enriched exosomes to be internalized into human mesenchymal stromal cells (MSCs) blocking osteoblast (OB) differentiation, increasing MM cell adhesion and the release of the pro-osteoclastogenic cytokine interleukin-8 (IL8). Accordingly, anti-AREG mAb inhibited the release of IL8 by MSCs suggesting that both direct and indirect effects are responsible for AREG-enriched exosomes involvement on MM-induced osteoclastogenesis.
CONCLUSIONS
In conclusion, our data indicate that AREG is packed into MM-derived exosomes and implicated in OC differentiation through an indirect mechanism mediated by OBs.
背景
多发性骨髓瘤（MM）是一种与溶骨性骨病相关的克隆性浆细胞恶性肿瘤。最近，虽然其潜在机制尚不清楚，但已证明 MM 衍生的外泌体在破骨细胞生成中起作用。由于外泌体衍生的表皮生长因子受体配体（EGFR）参与肿瘤相关性骨溶解，我们假设 EGFR 配体 Amphiregulin（AREG）可由 MM 衍生的外泌体递送至，并参与 MM 诱导的破骨细胞生成。
方法
从 MM1.S 细胞系的条件培养基和 MM 患者的骨髓（BM）血浆样本中分离出外泌体。将鼠源细胞系 RAW264.7 和原代人 CD14 细胞用作破骨细胞（OC）来源。
结果
我们发现 AREG 特异性富集于 MM 样本的外泌体中，并且外泌体衍生的 AREG 导致前 OC 中 EGFR 的激活，这表现为 RAW264.7 和 CD14 细胞中其下游 SNAIL 的 mRNA 表达增加。使用中和抗 AREG 单克隆抗体（mAb）可逆转此作用。因此，我们表明 MM 衍生的外泌体对破骨细胞分化的作用可通过用抗 AREG mAb 预处理外泌体而被抑制。此外，我们证明了富含 MM 衍生的 AREG 的外泌体能够被内化进入人间充质基质细胞（MSCs），从而阻断成骨细胞（OB）分化，增加 MM 细胞黏附和促破骨细胞生成细胞因子白细胞介素 8（IL8）的释放。相应地，抗 AREG mAb 抑制 MSCs 释放 IL8，表明 AREG 富含外泌体参与 MM 诱导的破骨细胞生成既存在直接作用，也存在间接作用。
结论
总之，我们的数据表明 AREG 被包装到 MM 衍生的外泌体中，并通过 OB 介导的间接机制参与 OC 分化。
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