Role of extracellular matrix malleability in mediating breast cancer cell invasion and migration

导管癌是乳腺癌中最常见的一种，并进展为浸润性导管癌 (IDC)当癌通过基底膜(BM)侵入间质组织时。入侵是一种 导管癌进展中与转移可能性增加相关的关键一步，即 乳腺癌最致命的方面。在转移过程中，癌细胞还必须在血管内侵入骨髓。 还有渗出物。癌细胞被认为在BM的侵袭过程中利用蛋白酶来降解BM 使用被称为invadoodia的专门结构。已知的非蛋白水解酶侵袭模式和 迁移，包括细胞挤过ECM中的孔，将被纳米孔的性质所抑制 BM。然而，生理性ECM是粘弹性的，表现出一些粘性流体的特征，并且 胞体力可以引起基质的流动和永久变形。换句话说，粘弹性ECM是 可延展性的，细胞产生的力量可能会扩张毛孔，为细胞提供机械地 重塑ECM，并在物理上为迁移扫清一条路径，而不依赖于蛋白酶。而延展性是 与基质粘度有关，它不同于基质弹性。有趣的是，恶性乳腺病变 发现比良性病变表现出更高程度的粘滞性。重要的是，延展性的概念可能 也与依赖于蛋白酶的迁移有关，因为蛋白酶的作用可能是使基质 更具延展性。在此应用程序中要测试的特定假设是延展性是一个关键的物理 介导蛋白依赖和非蛋白水解酶依赖的癌细胞侵袭的BM参数 迁移。这一假说得到了初步研究的支持，研究发现癌细胞可以入侵和迁移。 通过含有具有中等或高延展性的BM配体的纳米孔基质- 以独立的方式，利用侵入式突起发起入侵，但无法入侵和 在延展性较低的矩阵中迁移。这一假设将通过追求以下三个方面来检验 具体目标：(1)制造具有独立可调延展性的3D细胞培养材料 与乳腺上皮BM相关的配体和硬度；(2)决定ECM延展性如何调节 椎弓根突起；和(3)！确定潜在的蛋白酶的分子和生物物理机制- 通过具有不同延展性级别的ECM进行独立迁移。这种方法是创新的，因为 其重点在于了解延展性在调节非依赖和非依赖蛋白水解酶中的作用 侵袭和迁移，因为延展性是ECM的物理特性，与基质粘度有关，但 与弹性或密度不同，这在很大程度上被研究忽视了。拟议的研究是 有重要意义，因为它将揭示ECM延展性在调节蛋白酶依赖和 乳癌细胞非依赖于蛋白酶的侵袭和迁移，可能揭示以前未发现的 所描述的入侵或迁徙方式。

Ductal carcinoma is the most common form of breast cancer and progresses to Invasive Ductal Carcinoma (IDC) when the carcinoma invades through the basement membrane (BM) into the stromal tissue. Invasion is a key step in ductal carcinoma progression that is associated with an increased likelihood for metastasis, the most deadly aspect of breast cancer. During metastasis, cancer cells must also invade BM during intravasation and extravasation. Cancer cells are thought to utilize proteases to degrade the BM during invasion of the BM using specialized structures known as invadopodia. Known modes of protease-independent invasion and migration, involving cells squeezing through pores in the ECM, would be inhibited by the nanoporous nature of the BM. However, physiological ECM is viscoelastic, exhibiting some characteristics of viscous fluids, and cellular forces can induce flow and permanent deformation of the matrix. In other words, viscoelastic ECM is malleable, and cell generated forces may expand pores, providing a mechanism for cells to mechanically remodel the ECM and physically clear a path for migration, independent of proteases. While malleability is related to matrix viscosity, it is distinct from matrix elasticity. Interestingly, malignant breast lesions have been found to exhibit a greater degree of viscosity than benign lesions. Importantly, the concept of malleability might be relevant to protease-dependent migration as well, as the action of proteases may be to make the matrix more malleable. The specific hypothesis to be tested in this application is that malleability is a key physical parameter of the BM that mediates protease-dependent and protease-independent cancer cell invasion and migration. This hypothesis is supported by preliminary studies finding that cancer cells can invade and migrate through nanoporous matrices that contain BM ligands with intermediate or high-malleability in a protease- independent manner, utilizing invadopodial like protrusions to initiate invasion, but are unable to invade and migrate through matrices with low malleability. This hypothesis will be tested by pursuing the following three specific aims: (1) Fabricate materials for 3D cell culture with independently tunable malleability that present ligands and stiffness relevant to the BM of mammary epithelium; (2) Determine how ECM malleability regulates invadopodial protrusions; and (3)! Identify molecular and biophysical mechanisms underlying protease- independent migration through ECMs with different levels of malleability. This approach is innovative because of its focus on understanding the role of malleability in mediating protease-independent and -dependent invasion and migration, as malleability is a physical characteristic of ECM, related to matrix viscosity but distinct from elasticity or density, which has been largely ignored in studies to date. The proposed research is significant because it will reveal the role of ECM malleability in mediating both protease-dependent and protease-independent invasion and migration by breast cancer cells, potentially uncovering previously un- described modes of invasion or migration.