The topographic features of an implant, which mechanically regulate cell behaviors and functions, are critical for the clinical success in tissue regeneration. How cells sense and respond to the topographical cues, e.g., interfacial roughness, is yet to be fully understood and even debatable. Here, the mechanotransduction and fate determination of human mesenchymal stem cells (MSCs) on surface roughness gradients are systematically studied. The broad range of topographical scales and high‐throughput imaging is achieved based on a catecholic polyglycerol coating fabricated by a one‐step‐tilted dip‐coating approach. It is revealed that the adhesion of MSCs is biphasically regulated by interfacial roughness. The cell mechanotransduction is investigated from focal adhesion to transcriptional activity, which explains that cellular response to interfacial roughness undergoes a direct force‐dependent mechanism. Moreover, the optimized roughness for promoting cell fate specification is explored.

Material surface topographic features have been shown to be crucial for tissue regeneration and surface treatment of implanted devices. Many biomaterials were investigated with respect to the response of cells on surface roughness. However, some conclusions even conflicted with each other due to the unclear interplay of surface topographic features and substrate elastic features as well as the lack of mechanistic studies. Herein, wide-scale surface roughness gradient hydrogels, integrating the surface roughness from nanoscale to microscale with controllable stiffness, were developed via soft lithography with precise surface morphology. Based on this promising platform, we systematically studied the mechanosensitive response of human mesenchymal stem cells (MSCs) to a broad range of roughnesses (200 nm to 1.2 μm for R q) and different substrate stiffnesses. We observed that MSCs responded to surface roughness in a stiffness-dependent manner by reorganizing the surface hierarchical structure. Surprisingly, the cellular mechanoresponse and osteogenesis were obviously enhanced on very soft hydrogels (3.8 kPa) with high surface roughness, which was comparable to or even better than that on smooth stiff substrates. These findings extend our understanding of the interactions between cells and biomaterials, highlighting an effective noninvasive approach to regulate stem cell fate via synergetic physical cues.

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Our previous study demonstrated that conditional reprogramming (CR) allows the establishment of patient-derived normal and tumor epithelial cell cultures from a variety of tissue types including breast, lung, colon and prostate. Using CR, we have established matched normal and tumor cultures, GUMC-29 and GUMC-30 respectively, from a patient's prostatectomy specimen. These CR cells proliferate indefinitely in vitro and retain stable karyotypes. Most importantly, only tumor-derived CR cells (GUMC-30) produced tumors in xenografted SCID mice, demonstrating maintenance of the critical tumor phenotype. Characterization of cells with DNA fingerprinting demonstrated identical patterns in normal and tumor CR cells as well as in xenografted tumors. By flow cytometry, both normal and tumor CR cells expressed basal, luminal, and stem cell markers, with the majority of the normal and tumor CR cells expressing prostate basal cell markers, CD44 and Trop2, as well as luminal marker, CD13, suggesting a transit-amplifying phenotype. Consistent with this phenotype, real time RT-PCR analyses demonstrated that CR cells predominantly expressed high levels of basal cell markers (KRT5, KRT14 and p63), and low levels of luminal markers. When the CR tumor cells were injected into SCID mice, the expression of luminal markers (AR, NKX3.1) increased significantly, while basal cell markers dramatically decreased. These data suggest that CR cells maintain high levels of proliferation and low levels of differentiation in the presence of feeder cells and ROCK inhibitor, but undergo differentiation once injected into SCID mice. Genomic analyses, including SNP and INDEL, identified genes mutated in tumor cells, including components of apoptosis, cell attachment, and hypoxia pathways. The use of matched patient-derived cells provides a unique in vitro model for studies of early prostate cancer.

Cells reside in a dynamic microenvironment in which adhesive ligand availability, density, and diffusivity are key factors regulating cellular behavior. Here, the cellular response to integrin‐binding ligand dynamics by directly controlling ligand diffusivity via tunable ligand–surface interactions is investigated. Interestingly, cell spread on the surfaces with fast ligand diffusion is independent of myosin‐based force generation. Fast ligand diffusion enhances α5β1 but not αvβ3 integrin activation and initiates Rac and RhoA but not ROCK signaling, resulting in lamellipodium‐based fast cell spreading. Meanwhile, on surfaces with immobile ligands, αvβ3 and α5β1 integrins synergistically initiate intracellular‐force‐based canonical mechanotransduction pathways to enhance cell adhesion and osteogenic differentiation of stem cells. These results indicate the presence of heretofore‐unrecognized pathways, distinct from canonical actomyosin‐driven mechanisms, that are capable of promoting cell adhesion.