Zavrski Ivana, Krebbel Holger, Wildemann Britt, Heider Ulrike, Kaiser Martin, Possinger Kurt, Sezer Orhan
Department of Oncology and Hematology, University Hospital Charité, Berlin, Germany.
Biochem Biophys Res Commun. 2005 Jul 22;333(1):200-5. doi: 10.1016/j.bbrc.2005.05.098.
Cancer-induced bone disease results in bone destruction, pathological fractures, and pain. We hypothesized that the inhibition of the proteasome-ubiquitin system in osteoclasts could abolish the receptor activator of NF-kappaB ligand (RANKL) mediated osteoclast differentiation and function, since RANKL-mediated downstream signaling plays a crucial role in osteoclast life cycle. In this study, we examined the effects of the proteasome inhibitors MG-132 and MG-262 on RANKL-induced osteoclast differentiation and function. Osteoclast precursors from peripheral blood mononuclear cells were cultured in the presence of RANKL and M-CSF. Osteoclasts were identified as multi-nucleated TRAP-positive cells. Osteoclast function was quantified with the extent of dentine resorption and TRAP activity in culture supernatants. For the evaluation of the effects of proteasome inhibitors towards osteoclastogenesis, sub-apoptotic concentrations of MG-132 and MG-262 were used. Effects on NF-kappaB were obtained in treated and untreated osteoclasts. MG-132 and MG-262 inhibit both osteoclast differentiation and osteoclast function. 0.01 microM MG-132 induced a 3.2-fold (P = 0.004) and 0.001 microM MG-262 a 3.3-fold (P = 0.004) reduction of osteoclast differentiation, respectively. The resorption capacity was decreased 2.6- and 11.1-fold (P = 0.003) by treatment with 0.01 and 0.1 microM MG-132, and 14.2- and 16.6-fold (P = 0.003) by 0.001 and 0.01 microM MG-262, respectively. This decrease correlated with the extent of NF-kappaB binding capacity. In conclusion, this study shows for the first time that proteasome inhibitors act on osteoclast development and function at low concentrations and should be considered as potential drugs for the treatment of cancer-induced osteolytic bone disease.
癌症诱导的骨病会导致骨质破坏、病理性骨折和疼痛。我们推测，破骨细胞中蛋白酶体-泛素系统的抑制作用可能会消除核因子κB受体活化因子配体（RANKL）介导的破骨细胞分化和功能，因为RANKL介导的下游信号在破骨细胞生命周期中起着关键作用。在本研究中，我们检测了蛋白酶体抑制剂MG-132和MG-262对RANKL诱导的破骨细胞分化和功能的影响。将外周血单核细胞来源的破骨细胞前体在RANKL和巨噬细胞集落刺激因子（M-CSF）存在的情况下进行培养。破骨细胞被鉴定为多核抗酒石酸酸性磷酸酶（TRAP）阳性细胞。通过牙本质吸收程度和培养上清液中的TRAP活性来量化破骨细胞功能。为了评估蛋白酶体抑制剂对破骨细胞生成的影响，使用了亚凋亡浓度的MG-132和MG-262。在处理过和未处理的破骨细胞中检测对核因子κB的影响。MG-132和MG-262均抑制破骨细胞分化和破骨细胞功能。0.01微摩尔/升的MG-132分别使破骨细胞分化降低3.2倍（P = 0.004），0.001微摩尔/升的MG-262使破骨细胞分化降低3.3倍（P = 0.004）。用0.01和0.1微摩尔/升的MG-132处理后，吸收能力分别降低2.6倍和11.1倍（P = 0.003），用0.001和0.01微摩尔/升的MG-262处理后，吸收能力分别降低14.2倍和16.6倍（P = 0.003）。这种降低与核因子κB结合能力的程度相关。总之，本研究首次表明蛋白酶体抑制剂在低浓度下作用于破骨细胞的发育和功能，应被视为治疗癌症诱导的溶骨性骨病的潜在药物。
