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Sato G.H.,Manzanar Project Foundation | Sato J.D.,Manzanar Project Foundation | Okamoto T.,Hiroshima University | McKeehan W.L.,Texas A&M University | Barnes D.W.,Mount Desert Island Biological Laboratory
In Vitro Cellular and Developmental Biology - Animal | Year: 2010

Lack of tissue-specific differentiated functions of cells in tissue culture, once thought to be due to "dedifferentiation", was shown to be due to selective overgrowth of fibroblasts by a series of simple experiments that challenged the prevailing dogma. Following this insight, enrichment culture techniques (alternate animal and culture passage) were designed to give functionally differentiated tumor cells selective advantage over the fibroblasts. These experiments resulted in the derivation of a large number of functionally differentiated clonal strains of a range of cell types, providing the final point of destruction of the dogma of "dedifferentiation." Instead, the hypothesis was proposed that cells in culture accurately represent cells in vivo, but without the complex in vivo environment. With the development of hormonally defined media and its combination with functionally differentiated clonal cell lines, this concept has been strengthened and the potential of tissue culture studies has been greatly augmented. Hormonally defined media allow the culture of cell types that cannot be grown in conventional, serum-supplemented media. These approaches demonstrate that hormonal responses and dependencies can be discovered in culture. Following this thinking and the discovery of hormonal dependencies of cancer cells has led to a new rationale for therapy. Tissue culture and cell technology continue to play an important role in solving human health problems. © 2010 The Society for In Vitro Biology. Source


Okamoto T.,Hiroshima University | Sato J.D.,Manzanar Project Foundation | Barnes D.W.,Georgia Gwinnett College | Sato G.H.,Manzanar Project Foundation
Cytotechnology | Year: 2013

The demonstration that the "dedifferentiation" of cells commonly observed in the early days of tissue culture was due to selective overgrowth of fibroblasts led to enrichment culture techniques (alternate animal and culture passage) designed to give a selective advantage to functionally differentiated tumor cells. These experiments resulted in the derivation of a large number of functionally differentiated clonal strains of a range of cell types. These results gave rise to the hypothesis that cells in culture accurately represent cells in vivo but without the complex in vivo environment. This concept has been strengthened with the development of hormonally defined culture media in combination with functionally differentiated clonal cell lines, which have augmented the potential of tissue culture studies. The use of hormonally defined media in place of serum-supplemented media demonstrates that hormonal responses and dependencies can be discovered in culture. Discoveries of hormonal dependencies of cancer cells has led to therapies targeting intracellular signaling pathways while discoveries of hormonal responses of pluripotent cells are helping to identify the potential application of stem cells. In these and other ways tissue culture technology will continue to contribute to solving problems of human health. © 2013 Springer Science+Business Media Dordrecht. Source


Yamasaki S.,Hiroshima University | Nabeshima K.,Hiroshima University | Sotomaru Y.,Hiroshima University | Taguchi Y.,Hiroshima University | And 4 more authors.
International Journal of Developmental Biology | Year: 2013

Mouse embryonic stem (mES) cells and mouse induced pluripotent stem (miPS) cells are commonly maintained on inactivated mouse embryonic fibroblast feeder cells in medium supplemented with fetal bovine serum or proprietary replacements. An undefined medium containing unknown quantities of reagents has limited the development of applications for pluripotent cells because of the relative lack of knowledge regarding cell responses to differentiating growth factors. Therefore we developed a serum-free medium, designated ESF7, in which mES cells can be maintained in an undifferentiated state without feeder cells. The medium was tested for culturing miPS cells. The miPS cells have been maintained in ESF7 medium for more than 3 years with an undifferentiated phenotype manifested by the expression of pluripotency marker genes and alkaline phosphatase, and these cells exhibited largely normal karyotypes. Furthermore, we found that fibroblast growth factor-2 (FGF-2) with heparin induced miPS cell differentiation into neuronal cells, both in an adherent monolayer and in embryoid body suspension culture. Moreover, we found that FGF-2 with bone morphogenetic protein 2 induced miPS cell differentiation into cardiomyocytes in embryoid body suspension culture. Furthermore, we transplanted subcutaneously miPS cells maintained in ESF7 into the dorsal flanks of SCID mice; all of the transplants produced tumors with tissues derived from all three embryonic germ layers. As this simple serum-free adherent monoculture system supports the long-term propagation of pluripotent iPS cells in vitro, it will allow us to elucidate cell responses to growth factors under defined conditions, and it should provide useful information for differentiation protocols for human iPS cells. © 2013 UBC Press. Source

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