Stromal architecture directs early dissemination in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDA) is an extremely metastatic and lethal disease. Here, in both murine and human PDA, we demonstrate that extracellular matrix architecture regulates cell extrusion and subsequent invasion from intact ductal structures through tumor-associated collagen signatures (TACS). This results in early dissemination from histologically premalignant lesions and continual invasion from well-differentiated disease, and it suggests TACS as a biomarker to aid in the pathologic assessment of early disease. Furthermore, we show that pancreatitis results in invasion-conducive architectures, thus priming the stroma prior to malignant disease. Analysis in potentially novel microfluidic-derived microtissues and in vivo demonstrates decreased extrusion and invasion following focal adhesion kinase (FAK) inhibition, consistent with decreased metastasis. Thus, data suggest that targeting FAK or strategies to reengineer and normalize tumor microenvironments may have roles not only in very early disease, but also for limiting continued dissemination from unresectable disease. Likewise, it may be beneficial to employ stroma-targeting strategies to resolve precursor diseases such as pancreatitis in order to remove stromal architectures that increase risk for early dissemination

Discutindo a educação ambiental no cotidiano escolar: desenvolvimento de projetos na escola formação inicial e continuada de professores

A presente pesquisa buscou discutir como a Educação Ambiental (EA) vem sendo trabalhada, no Ensino Fundamental e como os docentes desta escola compreendem e vem inserindo a EA no cotidiano escolar., em uma escola estadual do município de Tangará da Serra/MT, Brasil. Para tanto, realizou-se entrevistas com os professores que fazem parte de um projeto interdisciplinar de EA na escola pesquisada. Verificou-se que o projeto da escola não vem conseguindo alcançar os objetivos propostos por: desconhecimento do mesmo, pelos professores; formação deficiente dos professores, não entendimento da EA como processo de ensino-aprendizagem, falta de recursos didáticos, planejamento inadequado das atividades. A partir dessa constatação, procurou-se debater a impossibilidade de tratar do tema fora do trabalho interdisciplinar, bem como, e principalmente, a importância de um estudo mais aprofundado de EA, vinculando teoria e prática, tanto na formação docente, como em projetos escolares, a fim de fugir do tradicional vínculo “EA e ecologia, lixo e horta”.Facultad de Humanidades y Ciencias de la Educació

Pathway to metastasis: carcinoma dissemination via organized collagen tracks

University of Minnesota Ph.D. dissertation.December 2017. Major: Biomedical Engineering. Advisor: Paolo Provenzano. 1 computer file (PDF); xv, 185 pages + supplementary video filesA vital part of the metastatic cascade that leads to cancer-related deaths is the initial dissemination of cancer cells from a confined lesion into neighboring tissue by migration and invasion. Breast and pancreatic carcinomas are often associated with increased deposition of collagen-I, which can assemble into aligned fiber tracks in mature breast tumors. Such aligned tracks provide contact guidance cues for directed cancer cell migration and dissemination leading to increased invasion, metastasis and decreased disease-free survival in breast cancer patients. Using multiphoton imaging, we demonstrate that organized collagen architectures develop in the pancreatic ductal adenocarcinoma (PDA) stroma even at the pre-invasive stage with single cells and multicellular clusters interacting with aligned collagen tracks in vivo. Mimicking the collagen patterns with microfabricated substrates, we show that for single cells, aligned architectures induce constrained focal adhesion maturation and associated F-actin alignment, consequently orchestrating anisotropic traction stresses that drive cell orientation and directional migration. While such interactions allow single mesenchymal-like cells to spontaneously “sense” and follow topographic alignment, intercellular interactions within epithelial clusters counteract anisotropic cell-substratum forces, resulting in substantially lower directional response. Indeed, anisotropic cell-substratum interactions from organized periductal collagen may contribute to cell extrusion and dissemination from pre-invasive ductal epithelia in PDA. Such contact guided spreading of cancer cells may be inhibited by dismantling the fiber architecture, diminishing its density or by abrogating cell-ECM interactions. To validate our findings in 3D we engineered novel in vitro substrates using a simple method to align 3D collagen gels by guided cellular compaction, to produce highly aligned, acellular collagen constructs as a controlled microenvironment in vitro. Additionally, we integrated the aligned collagen matrices to cell dense tumor-like plugs, allowing tracking of the temporal evolution of the advancing invasion fronts over several days. Live cell imaging and analysis of 3D cell migration revealed profoundly enhanced motility in aligned collagen matrices for the putative cancer stem cell subpopulation. Heterogeneity in cell migration behavior was also observed between cells at the leading edge and those within the tumor boundary, thus demonstrating the versatility of these platforms in capturing the dynamics of contact guided carcinoma dissemination

Aligned forces: Origins and mechanisms of cancer dissemination guided by extracellular matrix architecture

Organized extracellular matrix (ECM), in the form of aligned architectures, is a critical mediator of directed cancer cell migration by contact guidance, leading to metastasis in solid tumors. Current models suggest anisotropic force generation through the engagement of key adhesion and cytoskeletal complexes drives contact-guided migration. Likewise, disrupting the balance between cell-cell and cell-ECM forces, driven by ECM engagement for cells at the tumor-stromal interface, initiates and drives local invasion. Furthermore, processes such as traction forces exerted by cancer and stromal cells, spontaneous reorientation of matrix-producing fibroblasts, and direct binding of ECM modifying proteins lead to the emergence of collagen alignment in tumors. Thus, as we obtain a deeper understanding of the origins of ECM alignment and the mechanisms by which it is maintained to direct invasion, we are poised to use the new paradigm of stroma-targeted therapies to disrupt this vital axis of disease progression in solid tumors