Impact of extracellular matrix on breast cancer progression: a biomechanical and shotgun proteomic analysis . ver LC-MSMS

It has become increasingly evident that the local microenvironment of breast cancer (BC) plays an important role in its development and progression. A major component of this microenvironment is the extracellular matrix (ECM) that impact tumor progression. We recently identified an ECM gene expression pattern (ECM3) in ~40 % of BCs significantly associated with high risk of relapse only in patients with grade III tumors. To unravel the characteristic of this BC subgroup, in this study we investigated the biomechemical characteristics of ECM3 matrix in human BC samples with different grade. A collagen-reach matrix with several dense areas and a significantly higher value of stiffness distinguished ECM3 grade III tumors from the other breast carcinomas. Proteins recovered from decellularized BC matrices were analyzed by a shotgun label free proteomic approach. Principal Component Analysis on the total matrix proteome showed a significantly different protein repertoire in ECM3 grade III tumors, reflecting a deranged program of matrix biosynthesis in these tumors. A bioinformatic analysis in terms of pathways and GO enrichment focusing on the proteins more expressed or only expressed in ECM3 grade III BCs showed the significant enrichment of molecules involved in the focal adhesion and integrin pathway, ECM-receptor interaction, Tricarboxylic acid (TCA) cycle, ribosome and RNA transport. Obtained results indicate a marked interaction between ECM3 and undifferentiated BC cells that justifies an increased ribosome biogenesis needed at sites where local translation is required as focal adhesions. Moreover, the enrichment in decellularized matrices of molecules implicated in TCA cycle is indicative of a metabolic shift of these carcinomas toward energy production that gives them a selective advantage.

越来越多的研究表明，乳腺癌（BC）的局部微环境在其发生与进展过程中发挥着关键作用。该微环境的核心组成成分是影响肿瘤进展的细胞外基质（ECM）。我们近期在约40%的乳腺癌样本中鉴定出一种ECM基因表达谱（ECM3），该表达谱仅在III级肿瘤患者中与较高的复发风险显著相关。
为阐明该乳腺癌亚群的特征，本研究针对不同分级的人类乳腺癌样本中ECM3基质的生物化学特征展开了系统探究。相较于其他乳腺癌，ECM3阳性III级肿瘤具有富含胶原蛋白、存在多个致密区域以及显著更高的基质硬度等典型特征。
通过鸟枪式无标记蛋白质组学方法，研究人员对从脱细胞乳腺癌基质中回收的蛋白质进行了分析。对总基质蛋白质组开展的主成分分析显示，ECM3阳性III级肿瘤的蛋白质组成存在显著差异，反映出此类肿瘤中基质生物合成程序的紊乱状态。
针对ECM3阳性III级乳腺癌中高表达或特异性表达的蛋白质进行通路与基因本体（GO）富集分析的生物信息学研究结果显示，参与黏着斑与整合素通路、细胞外基质-受体相互作用、三羧酸（TCA）循环、核糖体合成以及RNA转运的分子呈现显著富集。
本研究结果表明，ECM3与未分化乳腺癌细胞之间存在显著的相互作用，这合理解释了在黏着斑这类需要局部翻译的位点所需的核糖体生物发生增加的现象。此外，脱细胞基质中富集的参与TCA循环的分子，提示此类肿瘤的代谢重编程朝向能量产生方向转变，从而使其获得了选择性生长优势。