Inhibition of metastatic outgrowth from single dormant tumor cells by targeting the cytoskeleton.
Inhibition of metastatic outgrowth from single dormant tumor cells by targeting the cytoskeleton.
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DOI：
10.1158/0008-5472.can-07-6849
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发表时间：
2008-08-01
期刊：
影响因子：
11.2
通讯作者：
Green JE
中科院分区：
文献类型：
--
作者：
Barkan D;Kleinman H;Simmons JL;Asmussen H;Kamaraju AK;Hoenorhoff MJ;Liu ZY;Costes SV;Cho EH;Lockett S;Khanna C;Chambers AF;Green JE
转移性乳腺癌可能出现在潜伏的肿瘤细胞中，这些肿瘤细胞在播散部位保持休眠多年。由于缺乏肿瘤细胞休眠的实验模型，识别调节从休眠到增殖转移生长的转换的机制一直是难以捉摸的。我们表征了在体内表现出休眠（D2 OR、MCF 7、K7 M2-AS.46）或增殖（D2.A1、MDA-MB-231、K7 M2）转移行为的细胞的体外生长特征。虽然这些细胞在2D培养中容易增殖，但我们证明，当在3D基质中生长时，细胞的不同生长特性与其在体内转移部位的休眠或增殖行为相关。在3D培养中，具有体内休眠行为的细胞保持细胞周期停滞，并且核中p16和p27表达升高。D2 A1细胞从静止到增殖的转变依赖于纤连蛋白的产生和通过整合素β1的信号传导，导致细胞骨架重组和f-肌动蛋白应力纤维的形成。我们证明，肌球蛋白轻链的磷酸化的MLC激酶（MLCK）通过整合素1所需的肌动蛋白应力纤维的形成和增殖生长。在体外，抑制整合素β1或MLCK可防止从静止状态向增殖状态的转变。抑制MLCK可显著减少体内转移性生长。这些研究表明，从休眠到转移性生长的转换可能部分地通过来自微环境的表观遗传信号传导来调节，从而导致休眠细胞的细胞骨架结构的变化。靶向这一过程可以提供抑制休眠到增殖转移开关的治疗策略。
Metastatic breast cancer may emerge from latent tumor cells that remain dormant at disseminated sites for many years. Identifying mechanisms regulating the switch from dormancy to proliferative metastatic growth has been elusive due to the lack of experimental models of tumor cell dormancy. We characterized the in vitro growth characteristics of cells that exhibit either dormant (D2OR, MCF7, K7M2-AS.46) or proliferative (D2.A1, MDA-MB-231, K7M2) metastatic behavior in vivo. Although these cells proliferate readily in 2D culture, we demonstrate that when grown in 3D matrix, distinct growth properties of the cells were revealed that correlate to their dormant or proliferative behavior at metastatic sites in vivo. In 3D culture, cells with dormant behavior in vivo remained cell cycle arrested with elevated nuclear expression of p16 and p27. The transition from quiescence to proliferation of D2A1 cells was dependent upon fibronectin production and signaling through integrin β1, leading to cytoskeletal reorganization with f-actin stress fiber formation. We demonstrate that phosphorylation of myosin light chain by MLC kinase (MLCK) through integrin 1 is required for actin stress fiber formation and proliferative growth. Inhibition of integrin β1 or MLCK prevents transition from a quiescent to proliferative state in vitro. Iinhibition of MLCK significantly reduces metastatic outgrowth in vivo. These studies demonstrate that the switch from dormancy to metastatic growth may be regulated, in part, through epigenetic signaling from the microenvironment leading to changes in the cytoskeletal architecture of dormant cells. Targeting this process may provide therapeutic strategies for inhibition of the dormant-to-proliferative metastatic switch.