Department of Biochemistry, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.
BMC Cancer. 2011 Jul 18;11:301. doi: 10.1186/1471-2407-11-301.
Multiple myeloma is an incurable disease requiring the development of effective therapies which can be used clinically. We have elucidated the potential for manipulating the cAMP signaling pathway as a target for inhibiting the growth of multiple myeloma cells.
As a model system, we primarily used the murine multiple myeloma cell line MOPC315 which can be grown both in vivo and in vitro. Human multiple myeloma cell lines U266, INA-6 and the B-cell precursor acute lymphoblastic leukemia cell line Reh were used only for in vitro studies. Cell death was assessed by flow cytometry and western blot analysis after treatment with cAMP elevating agents (forskolin, prostaglandin E2 and rolipram) and cAMP analogs. We followed tumor growth in vivo after forskolin treatment by imaging DsRed-labelled MOPC315 cells transplanted subcutaneously in BALB/c nude mice.
In contrast to the effect on Reh cells, 50 μM forskolin more than tripled the death of MOPC315 cells after 24 h in vitro. Forskolin induced cell death to a similar extent in the human myeloma cell lines U266 and INA-6. cAMP-mediated cell death had all the typical hallmarks of apoptosis, including changes in the mitochondrial membrane potential and cleavage of caspase 3, caspase 9 and PARP. Forskolin also inhibited the growth of multiple myeloma cells in a mouse model in vivo.
Elevation of intracellular levels of cAMP kills multiple myeloma cells in vitro and inhibits development of multiple myeloma in vivo. This strongly suggests that compounds activating the cAMP signaling pathway may be useful in the field of multiple myeloma.
多发性骨髓瘤是一种不可治愈的疾病，需要开发能够在临床上使用的有效疗法。我们已经阐明了操纵 cAMP 信号通路作为抑制多发性骨髓瘤细胞生长的靶点的潜力。
作为模型系统，我们主要使用了能够在体内和体外生长的鼠多发性骨髓瘤细胞系 MOPC315。人多发性骨髓瘤细胞系 U266、INA-6 和 B 细胞前体急性淋巴细胞白血病细胞系 Reh 仅用于体外研究。在用 cAMP 升高剂（forskolin、前列腺素 E2 和 rolipram）和 cAMP 类似物处理后，通过流式细胞术和 Western blot 分析评估细胞死亡。在用 forskolin 治疗后，我们通过对皮下移植 DsRed 标记的 MOPC315 细胞的 BALB/c 裸鼠进行成像来跟踪体内肿瘤生长。
与对 Reh 细胞的作用相反，50μM 的 forskolin在体外 24 小时后使 MOPC315 细胞的死亡增加了两倍多。forskolin 在人骨髓瘤细胞系 U266 和 INA-6 中诱导细胞死亡的程度相似。cAMP 介导的细胞死亡具有凋亡的所有典型特征，包括线粒体膜电位的变化和 caspase 3、caspase 9 和 PARP 的切割。forskolin 还抑制了体内多发性骨髓瘤细胞在小鼠模型中的生长。
细胞内 cAMP 水平的升高可在体外杀死多发性骨髓瘤细胞，并抑制体内多发性骨髓瘤的发展。这强烈表明激活 cAMP 信号通路的化合物可能在多发性骨髓瘤领域有用。
