Small GTP-binding protein Rho stimulates the actomyosin system, leading to invasion of tumor cells
Small GTP-binding protein Rho stimulates the actomyosin system, leading to invasion of tumor cells
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DOI：
10.1074/jbc.273.9.5146
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发表时间：
1998-02-27
影响因子：
4.8
通讯作者：
Itoh, K
中科院分区：
文献类型：
--
作者：
Yoshioka, K;Matsumura, F;Itoh, K
我们以前已经表明，Rho在1-油酰溶血磷脂酸（LPA）依赖的大鼠肝癌细胞（MM 1）的侵袭中起着关键作用。在此，我们制备了表达人RhoA的活性和肉毒杆菌外切酶C3（C3）-敏感（瓦尔（14））或活性和C3-不敏感（瓦尔（14）/Ile（41））形式的MM 1的稳定转染子。两种转染子在不存在LPA的情况下在体外以及在体内均显示出极大促进的侵袭能力，以分散的形状粘附于培养皿，MLC激酶特异性抑制剂KT 5926可抑制其侵袭能力和MLC 20的磷酸化水平，W1细胞（MM 1的低侵袭对应物）的稳定活性RhoA转染子也表现出在体外和体内促进的侵袭能力，并增强MLC 20的磷酸化水平。C3处理抑制了瓦尔（14）RhoA转染子的侵袭性，但不抑制瓦尔（14）/Ile（41）RhoA转染子的侵袭性。结果表明：1）Rho信号通路与肌动球蛋白系统在肿瘤细胞的迁移过程中相互作用; 2）表达活性RhoA的LPA通过激活内源性RhoA通路增强肿瘤细胞的侵袭力，提示RhoA的激活存在正反馈机制。
We have shown previously that Rho plays a pivotal role in 1-oleoyl-lysophosphatidic acid (LPA)-dependent invasion of rat hepatoma cells (MM1). Herein we made stable transfectants of MM1 expressing active and Botulinum exoenzyme C3 (C3)-sensitive (Val(14)), or active and C3-insensitive (Val(14)/Ile(41)) forms of human RhoA, Both transfectants showed greatly promoted invasive ability in vitro in the absence of LPA as well as in vivo, adherence to the dish with scattered shape, and enhanced phosphorylation level of 20-kDa myosin light chain (MLC20), A specific MLC kinase inhibitor (KT5926) could inhibit their invasion and the phosphorylation level of MLC20, Stable active RhoA transfectants of W1 cells (low invasive counterpart of MM1) also demonstrated promoted invasive ability in, vitro and in vivo, and enhanced phosphorylation level of MLC20. C3 treatment inhibited the invasiveness of the Val(14) RhoA transfectant but not that of the Val(14)/Ile(41) RhoA transfectant. LPA enhanced the invasiveness of both transfectants, and this enhancement was abolished by the C3 treatment, These results suggested that 1) the Rho signaling pathway and actomyosin system were linked in the transmigration of tumor cells, and 2) expressed active RhoA enhanced LPA-induced tumor cell invasion via the activation of endogenous RhoA pathway, indicating a positive feedback mechanism in the activation of RhoA.