LIMK2 promotes the metastatic progression of triple-negative breast cancer by activating SRPK1
LIMK2 promotes the metastatic progression of triple-negative breast cancer by activating SRPK1
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DOI：
10.1038/s41389-020-00263-1
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发表时间：
2020-08-28
期刊：
影响因子：
6.2
通讯作者：
Wajapeyee, Narendra
中科院分区：
文献类型：
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作者：
Malvi, Parmanand;Janostiak, Radoslav;Wajapeyee, Narendra
三阴性乳腺癌（TNBC）是一种高度转移的乳腺癌亚型，由于缺乏激素受体和HER2表达，TNBC的治疗选择有限，化疗是全身治疗的主要选择。LIM结构域激酶2 （LIMK2）是一种丝氨酸/苏氨酸激酶，在肌动蛋白丝动力学调节中起重要作用。在这里，我们发现LIM结构域激酶2 （LIMK2）在TNBC中过表达，短发卡RNA （shRNA）介导的LIMK2敲低或其药理抑制抑制了TNBC细胞的转移属性。为了确定LIMK2促进TNBC转移进展的机制，我们在细胞培养（SILAC）中进行了基于无偏大规模磷蛋白质组学分析的氨基酸稳定同位素标记。该分析确定了258个蛋白，其磷酸化因LIMK2抑制而显着降低。在这些蛋白中，我们鉴定出SRSF蛋白激酶1 (SRPK1)，它编码SR（丝氨酸/精氨酸富结构域）剪接因子家族特有的丝氨酸/精氨酸蛋白激酶。我们发现LIMK2抑制阻断了SRPK1的磷酸化及其活性。此外，与LIMK2类似，shRNAs对SRPK1的遗传抑制或其药理抑制可阻断TNBC细胞的转移特性。此外，LIMK2的药理抑制阻断了小鼠转移进展，而不影响原发肿瘤的生长。总之，这些结果确定了LIMK2作为TNBC远端转移的促进剂和阻止TNBC转移进展的潜在靶点。
Triple-negative breast cancer (TNBC) is a highly metastatic breast cancer subtype and due to the lack of hormone receptors and HER2 expression, TNBC has limited therapeutic options with chemotherapy being the primary choice for systemic therapy. LIM Domain Kinase 2 (LIMK2) is a serine/threonine kinase that plays an important role in the regulation of actin filament dynamics. Here, we show that LIM domain kinase 2 (LIMK2) is overexpressed in TNBC, and short-hairpin RNA (shRNA)-mediated LIMK2 knockdown or its pharmacological inhibition blocks metastatic attributes of TNBC cells. To determine the mechanism by which LIMK2 promotes TNBC metastatic progression, we performed stable isotope labeling by amino acids in cell culture (SILAC) based unbiased large-scale phosphoproteomics analysis. This analysis identified 258 proteins whose phosphorylation was significantly reduced due to LIMK2 inhibition. Among these proteins, we identified SRSF protein kinase 1 (SRPK1), which encodes for a serine/arginine protein kinase specific for the SR (serine/arginine-rich domain) family of splicing factors. We show that LIMK2 inhibition blocked SRPK1 phosphorylation and consequentially its activity. Furthermore, similar to LIMK2, genetic inhibition of SRPK1 by shRNAs or its pharmacological inhibition blocked the metastatic attributes of TNBC cells. Moreover, the pharmacological inhibition of LIMK2 blocked metastatic progression in mice without affecting primary tumor growth. In sum, these results identified LIMK2 as a facilitator of distal TNBC metastasis and a potential target for preventing TNBC metastatic progression.