Ali Roshia, Mir Hilal Ahmad, Hamid Rabia, Shah Riaz A, Khanday Firdous A, Bhat Sahar Saleem
Department of Biotechnology, University of Kashmir, Hazratbal, Srinagar, J&K, 190006, India.
Department of Biochemistry, University of Kashmir, Srinagar, J&K, 190006, India.
Protein J. 2021 Apr;40(2):234-244. doi: 10.1007/s10930-021-09963-y. Epub 2021 Jan 30.
Alpha-1-syntrophin (SNTA1) is emerging as a novel modulator of the actin cytoskeleton. SNTA1 binds to F-actin and regulates intracellular localization and activity of various actin organizing signaling molecules. Aberration in syntrophin signaling has been closely linked with deregulated growth connected to tumor development/metastasis and its abnormal over expression has been observed in breast cancer. In the present work the effect of jasplakinolide, an actin-binding cyclodepsipeptide, on the SNTA1 protein activity and SNTA1 mediated downstream cellular events was studied in MDA-MB-231 breast cancer cell line.
SNTA1 protein levels and phosphorylation status were determined in MDA-MB-231 cells post jasplakinolide exposure using western blotting and immunoprecipitation techniques respectively. MDA-MB-231 cells were transfected with WT SNTA1 and DM SNTA1 (Y phospho mutant) and simultaneously treated with jasplakinolide. The effect of jasplakinolide and SNTA1 protein on cell migration was determined using the boyden chamber assay.
Jasplakinolide treatment decreases proliferation of MDA-MB-231 cells in both dose and time dependent manner. Results suggest that subtoxic doses of jasplakinolide induce morphological changes in MDA-MB-231 cells from flat spindle shape adherent cells to round weakly adherent forms. Mechanistically, jasplakinolide treatment was found to decrease SNTA1 protein levels and its tyrosine phosphorylation status. Moreover, migratory potential of jasplakinolide treated cells was significantly inhibited in comparison to control cells.
Our results demonstrate that jasplakinolide inhibits cell migration by impairing SNTA1 functioning in breast cancer cells.
α-1-合成肌动蛋白（SNTA1）正逐渐成为一种新型的肌动蛋白细胞骨架调节剂。SNTA1与F-肌动蛋白结合，并调节各种肌动蛋白组织信号分子的细胞内定位和活性。合成肌动蛋白信号转导异常与肿瘤发生/转移相关的生长失调密切相关，并且在乳腺癌中观察到其异常过表达。在本研究中，在MDA-MB-231乳腺癌细胞系中研究了一种肌动蛋白结合环缩肽茉莉酮酸酯对SNTA1蛋白活性和SNTA1介导的下游细胞事件的影响。
分别使用蛋白质免疫印迹和免疫沉淀技术，测定茉莉酮酸酯处理后的MDA-MB-231细胞中SNTA1蛋白水平和磷酸化状态。用野生型SNTA1和DM SNTA1（Y磷酸突变体）转染MDA-MB-231细胞，并同时用茉莉酮酸酯处理。使用博伊登室试验测定茉莉酮酸酯和SNTA1蛋白对细胞迁移的影响。
茉莉酮酸酯处理以剂量和时间依赖性方式降低MDA-MB-231细胞的增殖。结果表明，亚毒性剂量的茉莉酮酸酯诱导MDA-MB-231细胞从扁平纺锤形贴壁细胞转变为圆形弱贴壁形式的形态变化。从机制上讲，发现茉莉酮酸酯处理可降低SNTA1蛋白水平及其酪氨酸磷酸化状态。此外，与对照细胞相比，茉莉酮酸酯处理的细胞的迁移潜力受到显著抑制。
我们的结果表明，茉莉酮酸酯通过损害乳腺癌细胞中的SNTA1功能来抑制细胞迁移。
