Volakis Leonithas I, Li Ruth, Ackerman William E, Mihai Cosmin, Bechel Meagan, Summerfield Taryn L, Ahn Christopher S, Powell Heather M, Zielinski Rachel, Rosol Thomas J, Ghadiali Samir N, Kniss Douglas A
Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio, United States of America.
Department of Obstetrics & Gynecology (Division of Maternal-Fetal Medicine and Laboratory of Perinatal Research), The Ohio State University, Columbus, Ohio, United States of America.
PLoS One. 2014 Feb 26;9(2):e86110. doi: 10.1371/journal.pone.0086110. eCollection 2014.
Cell migration plays a central role in the invasion and metastasis of tumors. As cells leave the primary tumor, they undergo an epithelial to mesenchymal transition (EMT) and migrate as single cells. Epithelial tumor cells may also migrate in a highly directional manner as a collective group in some settings. We previously discovered that myoferlin (MYOF) is overexpressed in breast cancer cells and depletion of MYOF results in a mesenchymal to epithelial transition (MET) and reduced invasion through extracellular matrix (ECM). However, the biomechanical mechanisms governing cell motility during MYOF depletion are poorly understood. We first demonstrated that lentivirus-driven shRNA-induced MYOF loss in MDA-MB-231 breast cancer cells (MDA-231(MYOF-KD)) leads to an epithelial morphology compared to the mesenchymal morphology observed in control (MDA-231(LTVC)) and wild-type cells. Knockdown of MYOF led to significant reductions in cell migration velocity and MDA-231(MYOF-KD) cells migrated directionally and collectively, while MDA-231(LTVC) cells exhibited single cell migration. Decreased migration velocity and collective migration were accompanied by significant changes in cell mechanics. MDA-231(MYOF-KD) cells exhibited a 2-fold decrease in cell stiffness, a 2-fold increase in cell-substrate adhesion and a 1.5-fold decrease in traction force generation. In vivo studies demonstrated that when immunocompromised mice were implanted with MDA-231(MYOF-KD) cells, tumors were smaller and demonstrated lower tumor burden. Moreover, MDA-231(MYOF-KD) tumors were highly circularized and did not invade locally into the adventia in contrast to MDA-231(LTVC)-injected animals. Thus MYOF loss is associated with a change in tumor formation in xenografts and leads to smaller, less invasive tumors. These data indicate that MYOF, a previously unrecognized protein in cancer, is involved in MDA-MB-231 cell migration and contributes to biomechanical alterations. Our results indicate that changes in biomechanical properties following loss of this protein may be an effective way to alter the invasive capacity of cancer cells.
细胞迁移在肿瘤的侵袭和转移中起着核心作用。当细胞离开原发性肿瘤时，它们会经历上皮-间质转化（EMT）并以单细胞形式迁移。在某些情况下，上皮肿瘤细胞也可能作为一个集体以高度定向的方式迁移。我们之前发现，肌铁蛋白（MYOF）在乳腺癌细胞中过表达，MYOF的缺失会导致间质-上皮转化（MET）并减少通过细胞外基质（ECM）的侵袭。然而，在MYOF缺失期间控制细胞运动的生物力学机制仍知之甚少。我们首先证明，与对照（MDA-231（LTVC））和野生型细胞中观察到的间质形态相比，慢病毒驱动的shRNA诱导MDA-MB-231乳腺癌细胞（MDA-231（MYOF-KD））中MYOF缺失会导致上皮形态。敲低MYOF导致细胞迁移速度显著降低，MDA-231（MYOF-KD）细胞定向且集体迁移，而MDA-231（LTVC）细胞表现出单细胞迁移。迁移速度降低和集体迁移伴随着细胞力学的显著变化。MDA-231（MYOF-KD）细胞的细胞硬度降低了2倍，细胞与底物的粘附增加了2倍，产生的牵引力降低了1.5倍。体内研究表明，当将免疫缺陷小鼠植入MDA-231（MYOF-KD）细胞时，肿瘤较小且肿瘤负荷较低。此外，与注射MDA-231（LTVC）的动物相比，MDA-231（MYOF-KD）肿瘤高度呈圆形，并且不会局部侵入外膜。因此，MYOF缺失与异种移植中肿瘤形成的变化相关，并导致更小、侵袭性更低的肿瘤。这些数据表明，MYOF是一种先前在癌症中未被识别的蛋白质，参与MDA-MB-231细胞迁移并导致生物力学改变。我们的结果表明，这种蛋白质缺失后生物力学特性的变化可能是改变癌细胞侵袭能力的有效方法。
