title: In Vivo Visualization and Characterization of Epithelial-Mesenchymal Transition in Breast Tumors.
abstract: The activation of the epithelial-to-mesenchymal transition (EMT) program is a critical step in cancer progression and metastasis, but visualization of this process at the single-cell level, especially in vivo, remains challenging. We established an in vivo approach to track the fate of tumor cells based on a novel EMT-driven fluorescent color switching breast cancer mouse model and intravital two-photon laser scanning microscopy. Specifically, the MMTV-PyMT, Rosa26-RFP-GFP, and Fsp1-Cre triple transgenic mouse model was used to monitor the conversion of RFP-positive epithelial cells to GFP-positive mesenchymal cells in mammary tumors under the control of the Fsp1 (ATL1) promoter, a gate-keeper of EMT initiation. RFP-positive cells were isolated from the tumors, sorted, and transplanted into mammary fat pads of SCID mice to monitor EMT during breast tumor formation. We found that the conversion from RFP- to GFP-positive and spindle-shaped cells was a gradual process, and that GFP-positive cells preferentially localized close to blood vessels, independent of tumor size. Furthermore, cells undergoing EMT expressed high levels of the HGF receptor, c-Met, and treatment of RFP-positive cells with the c-Met inhibitor, cabozantinib, suppressed the RFP-to-GFP conversion in vitro Moreover, administration of cabozantinib to mice with palpable RFP-positive tumors resulted in a silent EMT phenotype whereby GFP-positive cells exhibited reduced motility, leading to suppressed tumor growth. In conclusion, our imaging technique provides a novel opportunity for visualizing tumor EMT at the single-cell level and may help to reveal the intricacies underlying tumor dynamics and treatment responses. Cancer Res; 76(8); 2094-104. ©2016 AACR.
authors.affiliation: Department of Radiology, Zhong-Da Hospital, Southeast University, Nanjing 210009, China.|Department of Systems Medicine and Bioengineering, Houston Methodist Research Institute, Weill Cornell Medicine, Houston, TX 77030, USA.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Zhao
authors.affiliation: Department of Systems Medicine and Bioengineering, Houston Methodist Research Institute, Weill Cornell Medicine, Houston, TX 77030, USA.
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Zhu
authors.affiliation: Department of Systems Medicine and Bioengineering, Houston Methodist Research Institute, Weill Cornell Medicine, Houston, TX 77030, USA.
authors.forename: Kemi
authors.initials: K
authors.lastname: Cui
authors.affiliation: Department of Systems Medicine and Bioengineering, Houston Methodist Research Institute, Weill Cornell Medicine, Houston, TX 77030, USA.
authors.forename: James
authors.initials: J
authors.lastname: Mancuso
authors.affiliation: Department of Systems Medicine and Bioengineering, Houston Methodist Research Institute, Weill Cornell Medicine, Houston, TX 77030, USA.
authors.forename: Richard
authors.initials: R
authors.lastname: Federley
authors.affiliation: Department of Cell and Developmental Biology, Weill Cornell Medicine, New York 10065, USA.
authors.forename: Kari
authors.initials: K
authors.lastname: Fischer
authors.affiliation: Department of Radiology, Zhong-Da Hospital, Southeast University, Nanjing 210009, China.
authors.forename: Gaojun
authors.initials: G
authors.lastname: Teng
authors.affiliation: Department of Cell and Developmental Biology, Weill Cornell Medicine, New York 10065, USA.
authors.forename: Vivek
authors.initials: V
authors.lastname: Mittal
authors.affiliation: Department of Cell and Developmental Biology, Weill Cornell Medicine, New York 10065, USA.
authors.forename: Dingcheng
authors.initials: D
authors.lastname: Gao
authors.affiliation: Department of Systems Medicine and Bioengineering, Houston Methodist Research Institute, Weill Cornell Medicine, Houston, TX 77030, USA.|NCI Center for Modeling Cancer Development, Houston Methodist Research Institute, Weill Cornell Medicine, Houston, TX 77030, USA.
authors.forename: Hong
authors.initials: H
authors.lastname: Zhao
authors.affiliation: Department of Systems Medicine and Bioengineering, Houston Methodist Research Institute, Weill Cornell Medicine, Houston, TX 77030, USA.|NCI Center for Modeling Cancer Development, Houston Methodist Research Institute, Weill Cornell Medicine, Houston, TX 77030, USA.|Houston Methodist Cancer Center, Houston Methodist Hospital, Houston, TX 77030, USA.
authors.forename: Stephen Tc
authors.initials: ST
authors.lastname: Wong
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D058750:Epithelial-Mesenchymal Transition; D005260:Female; D008325:Mammary Neoplasms, Experimental / Q000000981:diagnostic imaging / Q000473:pathology*; D051379:Mice; D016513:Mice, SCID; D008822:Mice, Transgenic; D008856:Microscopy, Fluorescence / Q000379:methods