Rac1 and Rac3 isoform activation is involved in the invasive and metastatic phenotype of human breast cancer cells.
Rac1 and Rac3 isoform activation is involved in the invasive and metastatic phenotype of human breast cancer cells.
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DOI：
10.1186/bcr1329
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发表时间：
2005
期刊：
影响因子：
--
通讯作者：
Dharmawardhane SF
中科院分区：
文献类型：
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作者：
Baugher PJ;Krishnamoorthy L;Price JE;Dharmawardhane SF
癌症的转移进展是许多细胞信号传导途径失调的直接结果，包括与粘附、迁移和侵袭相关的那些。已知小GTP酶的Rac家族的成员作为肌动蛋白细胞骨架结构的调节剂，并且强烈影响整联蛋白介导的粘附和迁移的细胞过程。尽管超活化的Rac蛋白已被证明影响转移过程，但这些蛋白从未与转移进展直接相关。为了研究Rac和Cdc 42在转移性乳腺癌细胞侵袭和迁移中的作用，使用p21结合结构域-PAK下拉测定法在MDA-MB-435转移性人乳腺癌细胞系的一组转移性变体中测定相对内源性Rac或Cdc 42活性。为了研究Rac亚型在人乳腺癌中的迁移和侵袭潜力，即Rac 1和随后克隆的Rac 3，我们将显性活性Rac 1或显性活性Rac 3稳定表达到转移性最小的细胞变体中。显性负性Rac 1或显性负性Rac 3在转移性最强的细胞变异体中稳定表达。使用体外粘附、迁移和侵袭测定分析表达突变体Rac 1或Rac 3的细胞系。我们发现，Rac蛋白的活化增加与来自单一转移性乳腺癌细胞系（MDA-MB-435）的一组细胞变体中转移潜能的增加直接相关。同样的相关性不能被发现与激活Cdc 42。显性活性Rac 1或显性活性Rac 3的表达导致更具侵袭性和运动性的表型。此外，显性阴性Rac 1或显性阴性Rac 3表达到最具转移性的细胞变体中导致侵袭性和运动性降低。本研究将内源性Rac活性与高转移潜能相关联，并暗示Rac在转移性乳腺癌细胞中调节细胞迁移和侵袭。总之，这些结果表明Rac 1和Rac 3 GTP酶在人类乳腺癌进展中的作用。
The metastatic progression of cancer is a direct result of the disregulation of numerous cellular signaling pathways, including those associated with adhesion, migration, and invasion. Members of the Rac family of small GTPases are known to act as regulators of actin cytoskeletal structures and strongly influence the cellular processes of integrin-mediated adhesion and migration. Even though hyperactivated Rac proteins have been shown to influence metastatic processes, these proteins have never been directly linked to metastatic progression. To investigate a role for Rac and Cdc42 in metastatic breast cancer cell invasion and migration, relative endogenous Rac or Cdc42 activity was determined in a panel of metastatic variants of the MDA-MB-435 metastatic human breast cancer cell line using a p21-binding domain-PAK pull down assay. To investigate the migratory and invasive potential of the Rac isoforms in human breast cancer, namely Rac1 and the subsequently cloned Rac3, we stably expressed either dominant active Rac1 or dominant active Rac3 into the least metastatic cell variant. Dominant negative Rac1 or dominant negative Rac3 were stably expressed in the most metastatic cell variant. Cell lines expressing mutant Rac1 or Rac3 were analyzed using in vitro adhesion, migration and invasion assays. We show that increased activation of Rac proteins directly correlates with increasing metastatic potential in a panel of cell variants derived from a single metastatic breast cancer cell line (MDA-MB-435). The same correlation could not be found with activated Cdc42. Expression of a dominant active Rac1 or a dominant active Rac3 resulted in a more invasive and motile phenotype. Moreover, expression of either dominant negative Rac1 or dominant negative Rac3 into the most metastatic cell variant resulted in decreased invasive and motile properties. This study correlates endogenous Rac activity with high metastatic potential and implicates Rac in the regulation of cell migration and invasion in metastatic breast cancer cells. Taken together, these results suggest a role for both the Rac1 and Rac3 GTPases in human breast cancer progression.