Co-cultivation Of Fibroblasts Research Articles

Three-dimensional hierarchical cultivation of human skin cells on bio-adaptive hybrid fibers.

The human skin comprises a complex multi-scale layered structure with hierarchical organization of different cells within the extracellular matrix (ECM). This supportive fiber-reinforced structure provides a dynamically changing microenvironment with specific topographical, mechanical and biochemical cell recognition sites to facilitate cell attachment and proliferation. Current advances in developing artificial matrices for cultivation of human cells concentrate on surface functionalizing of biocompatible materials with different biomolecules like growth factors to enhance cell attachment. However, an often neglected aspect for efficient modulation of cell-matrix interactions is posed by the mechanical characteristics of such artificial matrices. To address this issue, we fabricated biocompatible hybrid fibers simulating the complex biomechanical characteristics of native ECM in human skin. Subsequently, we analyzed interactions of such fibers with human skin cells focusing on the identification of key fiber characteristics for optimized cell-matrix interactions. We successfully identified the mediating effect of bio-adaptive elasto-plastic stiffness paired with hydrophilic surface properties as key factors for cell attachment and proliferation, thus elucidating the synergistic role of these parameters to induce cellular responses. Co-cultivation of fibroblasts and keratinocytes on such fiber mats representing the specific cells in dermis and epidermis resulted in a hierarchical organization of dermal and epidermal tissue layers. In addition, terminal differentiation of keratinocytes at the air interface was observed. These findings provide valuable new insights into cell behaviour in three-dimensional structures and cell-material interactions which can be used for rational development of bio-inspired functional materials for advanced biomedical applications.

Induction of matrix metalloproteinase 9 expression in breast carcinoma cells by a soluble factor from fibroblasts.

Tumor-stromal interactions appear to play an important role in the induction of metalloproteinase expression in malignant tumors. We describe a tissue culture system in which expression of MMP-9 (gelatinase B or the 92 kDa type IV collagenase/gelatinase) was induced by co-cultivation of fibroblasts with breast cancer cell lines. While neither the breast cancer cells nor the normal rat embryo fibroblasts made MMP-9 alone in culture, human MMP-9 was made in the co-cultures. The MMP-9 was secreted in a latent form. The induction occurred at least in part through increases in the MMP-9 mRNA levels in the breast cancer cells. These increases did not appear to require protein synthesis. Conditioned medium from the fibroblasts could duplicate the induction of MMP-9 in the breast cancer cell lines. The active factor in the medium was inactivated by heat or by trypsin suggesting that it was a protein. This protein was in the size range of 30-100 kDa. Thus, fibroblasts could secrete a factor which was able to regulate the expression of MMP-9 in breast cancer cells.