TY - JOUR
T1 - In Vivo Visualization and Characterization of Epithelial-Mesenchymal Transition in Breast Tumors
AU - Zhao, Zhen
AU - Zhu, Xiaoping
AU - Cui, Kemi
AU - Mancuso, James
AU - Federley, Richard
AU - Fischer, Kari
AU - Teng, Gao Jun
AU - Mittal, Vivek
AU - Gao, Dingcheng
AU - Zhao, Hong
AU - Wong, Stephen T.C.
N1 - Funding Information:
This research was funded by NIH U54 CA149196 and a John S. Dunn Research Foundation grant (S.T.C. Wong), and an NIH U54 CA149196 pilot project grant (H. Zhao). The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked advertisement in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
Publisher Copyright:
©2016 American Association for Cancer Research.
PY - 2016/4/15
Y1 - 2016/4/15
N2 - 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 EMTdriven 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 gatekeeper 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 spindleshaped 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.
AB - 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 EMTdriven 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 gatekeeper 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 spindleshaped 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.
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U2 - 10.1158/0008-5472.CAN-15-2662
DO - 10.1158/0008-5472.CAN-15-2662
M3 - Article
C2 - 26893478
AN - SCOPUS:84964560527
SN - 0008-5472
VL - 76
SP - 2094
EP - 2104
JO - Cancer research
JF - Cancer research
IS - 8
ER -