Biomimetic Matrix Stiffness Modulates Hepatocellular Carcinoma Malignant Phenotypes and Macrophage Polarization through Multiple Modes of Mechanical Feedbacks

The extracellular matrix (ECM) stiffening is an important sign of local microenvironment change, which is considered as a hallmark of many diseases including hepatocellular carcinoma (HCC). The fates of both cancer cells and immune cells can be regulated by mechanical feedbacks acquired from ECM, but there is a lack of a precise study of mechanical feedback modes in different cell phenotypes following with the progressively increasing ECM stiffness. Herein, we used a biopolymeric film without further modification of adhesive molecules, as a natural local niche to mimic a gradually stiffening manner from HCC onset in liver cirrhosis to its metastasis in the spinal cord. Three distinct manners of mechanical feedbacks were found: the gradual manner in HCC cell spreading, migration and early apoptosis to oxaliplatin, the stepwise manner in HCC cell adhesion, proliferation, focal adhesion (FA) formation, drug resistance, and macrophage M1 polarization; the specific manner in the stages of the progression of epithelial-mesenchymal transition at different stiffness ranges. Further investigation of molecular mechanisms confirmed those mechanical feedback manners by signaling activation of FA kinase, phosphatidylinositol 3-kinase, and expression of pro-/antiapoptotic and pro-/anti-inflammatory genes. Our results pave a novel avenue to know about mechanical feedbacks from ECM, which could be used for future cancer studies and in vitro drug screening applications.