title: In vivo cell-cycle profiling in xenograft tumors by quantitative intravital microscopy.
abstract: Quantification of cell-cycle state at a single-cell level is essential to understand fundamental three-dimensional (3D) biological processes such as tissue development and cancer. Analysis of 3D in vivo images, however, is very challenging. Today's best practice, manual annotation of select image events, generates arbitrarily sampled data distributions, which are unsuitable for reliable mechanistic inferences. Here, we present an integrated workflow for quantitative in vivo cell-cycle profiling. It combines image analysis and machine learning methods for automated 3D segmentation and cell-cycle state identification of individual cell-nuclei with widely varying morphologies embedded in complex tumor environments. We applied our workflow to quantify cell-cycle effects of three antimitotic cancer drugs over 8 d in HT-1080 fibrosarcoma xenografts in living mice using a data set of 38,000 cells and compared the induced phenotypes. In contrast to results with 2D culture, observed mitotic arrest was relatively low, suggesting involvement of additional mechanisms in their antitumor effect in vivo.
authors: Department of Cell Biology, Harvard Medical School, Boston, Massachusetts, USA.
authors: Deepak R
authors: DR
authors: Chittajallu
authors: Department of Systems Biology, Harvard Medical School, Boston, Massachusetts, USA.
authors: Stefan
authors: S
authors: Florian
authors: Center for Systems Biology, Massachusetts General Hospital, Boston, Massachusetts, USA.
authors: Rainer H
authors: RH
authors: Kohler
authors: Center for Systems Biology, Massachusetts General Hospital, Boston, Massachusetts, USA.
authors: Yoshiko
authors: Y
authors: Iwamoto
authors: Molecular, Cellular and Developmental Biology, University of Colorado Boulder, Boulder, Colorado, USA.
authors: James D
authors: JD
authors: Orth
authors: 1] Department of Systems Biology, Harvard Medical School, Boston, Massachusetts, USA. [2] Center for Systems Biology, Massachusetts General Hospital, Boston, Massachusetts, USA.
authors: Ralph
authors: R
authors: Weissleder
authors: Department of Cell Biology, Harvard Medical School, Boston, Massachusetts, USA.
authors: Gaudenz
authors: G
authors: Danuser
authors: Department of Systems Biology, Harvard Medical School, Boston, Massachusetts, USA.
authors: Timothy J
authors: TJ
authors: Mitchison
mesh_terms: D000818:Animals; D002453:Cell Cycle / Q000502:physiology*; D015972:Gene Expression Regulation, Neoplastic; D007091:Image Processing, Computer-Assisted; D051379:Mice; D008853:Microscopy / Q000379:methods*; D009374:Neoplasms, Experimental / Q000378:metabolism*; D059467:Transcriptome