Jami Mandelin

Publications (2)32.04 Total impact

• Source

  Available from: Jennifer R Molina

  Article: Three-dimensional tissue culture based on magnetic cell levitation.

  Glauco R Souza, Jennifer R Molina, Robert M Raphael, Michael G Ozawa, Daniel J Stark, Carly S Levin, Lawrence F Bronk, Jeyarama S Ananta, Jami Mandelin, Maria-Magdalena Georgescu, James A Bankson, Juri G Gelovani, T C Killian, Wadih Arap, Renata Pasqualini
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  ABSTRACT: Cell culture is an essential tool in drug discovery, tissue engineering and stem cell research. Conventional tissue culture produces two-dimensional cell growth with gene expression, signalling and morphology that can be different from those found in vivo, and this compromises its clinical relevance. Here, we report a three-dimensional tissue culture based on magnetic levitation of cells in the presence of a hydrogel consisting of gold, magnetic iron oxide nanoparticles and filamentous bacteriophage. By spatially controlling the magnetic field, the geometry of the cell mass can be manipulated, and multicellular clustering of different cell types in co-culture can be achieved. Magnetically levitated human glioblastoma cells showed similar protein expression profiles to those observed in human tumour xenografts. Taken together, these results indicate that levitated three-dimensional culture with magnetized phage-based hydrogels more closely recapitulates in vivo protein expression and may be more feasible for long-term multicellular studies.
  Nature Nanotechnology 03/2010; 5(4):291-6. · 27.27 Impact Factor
• Article: Extracellular and intracellular mechanisms that mediate the metastatic activity of exogenous osteopontin.

  Jami Mandelin, Emme C K Lin, Dana D Hu, Susan K Knowles, Kim-Anh Do, Xuemei Wang, E Helene Sage, Jeffrey W Smith, Wadih Arap, Renata Pasqualini
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  ABSTRACT: Osteopontin affects several steps of the metastatic cascade. Despite direct correlation with metastasis in experimental systems and in patient studies, the extracellular and intracellular basis for these observations remains unsolved. In this study, the authors used human melanoma and sarcoma cell lines to evaluate the effects of soluble osteopontin on metastasis. Exogenous osteopontin or negative controls, including a site-directed mutant osteopontin, were used in functional assays in vitro, ex vivo, and in vivo that were designed to test the extracellular and intracellular mechanisms involved in experimental metastasis. In the extracellular environment, the results confirmed that soluble osteopontin is required for its prometastatic effects; this phenomenon is specific, arginine-glycine-aspartic acid (RGD)-dependent, and evident in experimental models of metastasis. In the intracellular environment, osteopontin initially induced rapid tyrosine 418 (Tyr-418) dephosphorylation of the cellular homolog of the Rous sarcoma virus (c-Src), with decreases in actin stress fibers and increased binding to the vascular endothelium. This heretofore undescribed Tyr dephosphorylation was followed by a tandem c-Src phosphorylation after tumor cell attachment to the metastatic site. The results of this study revealed a complex molecular interaction as well as a dual role for osteopontin in metastasis that depends on whether tumor cells are in circulation or attached. Such context-dependent functional insights may contribute to antimetastasis strategies.
  Cancer 03/2009; 115(8):1753-64. · 4.77 Impact Factor