title: A 3D in situ cell counter reveals that breast tumor cell (MDA-MB-231) proliferation rate is reduced by the collagen matrix density.
abstract: Many cell types require the biophysical and biochemical cues within the 3D extracellular matrix (ECM) to exhibit their true physiologically relevant behavior. As a result, cell culture platforms have been evolving from traditional 2D petridish plates into 3D biomatrices, and there is a need for developing analytic tools to characterize 3D cell culture. The existing cell counting method, using a hemocytometer or coulter counter, requires that cells are suspended in fluids prior to counting. This poses a challenge for 3D cell culture as cells are embedded in a 3D biomatrix. We use a facile 3D cell counting method that overcomes this limitation and allows for in situ cell counting in a 3D cell culture using equipment that is commonly available in a biology lab. Using a breast tumor cell line, MDA-MB-231, as a model system, we demonstrated that MDA-MB-231 cells (1) grow slower within a 3D collagen matrix than on a 2D substrate for an extended growth time (a week) with a comparable, initial cell-to-cell distance, (2) their cell growth rate decreases with the increase of collagen concentration, showing a linear growth rate rather than an exponential growth rate. Further work using flow cytometry showed that the observed growth rate reduction was consistent with the retardation of the transition to S (synthesis) phase in the cell cycle. This work demonstrates the validity of the 3D cell counting method and the importance of cell-ECM interactions in cell proliferation.
authors: Dept. of Biological and Environmental Engineering, Cornell University, Ithaca, NY 14853.
authors: Beum Jun
authors: BJ
authors: Kim
authors: Dept. of Biological and Environmental Engineering, Cornell University, Ithaca, NY 14853.
authors: Shuting
authors: S
authors: Zhao
authors: Dept. of Biomedical Sciences, Cornell University, Ithaca, NY 14853.
authors: Rodica P
authors: RP
authors: Bunaciu
authors: Dept. of Biomedical Sciences, Cornell University, Ithaca, NY 14853.
authors: Andrew
authors: A
authors: Yen
authors: Dept. of Biological and Environmental Engineering, Cornell University, Ithaca, NY 14853.
authors: Mingming
authors: M
authors: Wu
mesh_terms: D002452:Cell Count / Q000295:instrumentation* / Q000379:methods*; D018929:Cell Culture Techniques / Q000295:instrumentation / Q000379:methods*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D003094:Collagen / Q000494:pharmacology*; D006801:Humans; D015203:Reproducibility of Results
chemical_list: D003094:Collagen
keywords: 3D ECM; cell cycle; cell growth; collagen; hemocytometer