# To study the EMT contributions in tumor metastasis and chemoresistance by using lineage tracing models

> **NIH NIH R01** · WEILL MEDICAL COLL OF CORNELL UNIV · 2020 · $506,382

## Abstract

Epithelial to mesenchymal transition (EMT) has been enthusiastically proposed as an essential mechanism for
tumor metastasis, since the EMT-associated features such as migration, invasion, resistance to apoptosis and
stemness properties, adequately meet the requirements for metastasis. Taken the challenges of tracing the EMT
process in vivo, we developed a strategy of using a mesenchymal-specific Cre-mediated switch of fluorescent
markers in a multiple-transgenic mouse (MMTV-PyMT:Fsp1-Cre:Rosa26mT/mG, Tri-PyMT). Surprisingly, we
found that lung metastases were predominantly composed of pre-EMT RFP+ tumor cells exhibiting epithelial
phenotypes under normal conditions. Importantly, the post-EMT tumor cells did exhibit resistance to
chemotherapy, significantly contributed to recurrent lung metastases after chemotherapy. These findings pointed
to the complexity of EMT contributions in tumor progression and revived vigorous discussions in the community.
Given the transient, reversible and dynamic natures of the EMT process, and concerns about the Tri-PyMT
model, we proposed new lineage tracing models to study the roles of EMT in metastasis and chemoresistance.
Aim 1. To explore the contributions of EMT mechanism in tumor metastasis and chemoresistance by
using Snail-CreERT2 mediated EMT lineage tracing model. The Fsp1-Cre mediated Tri-PyMT model may not
be sufficient to report all EMT events. Metastatic cells could undergo EMT by activating distinct EMT transcription
factors (TFs) such as Snail. Therefore, we have established a Snail-CreERT2–mediated EMT lineage tracing
model. In-depth analyses will be performed to clarify the roles of EMT in metastasis and chemoresistance with
this model.
Aim 2. To explore the dynamic changes of EMT statuses in human breast cancer metastasis and
chemoresistance. EMT reporter cell lines (MDA-MB-231:Vim/RFP and BT-474:ECAD/GFP cells) carry knockin
fluorescent tags within EMT marker genes (Vimentin and E-cadherin, respectively). Unlike the Cre-mediated
models, the fluorescence expression in these cells is quantitative and reversible, which allows us to analyze the
dynamic changes of EMT status with and without chemotherapy in human breast cancer models.
Aim 3. To assess the evolutionary lineages of metastasis-initiating cells and the involvement of EMT
mechanism via genetic barcoding models. In addition to using EMT markers, we will genetically barcode the
Tri-PyMT cells using the homing-CRISPR technique. This model will allow us to depict the evolutionary
trajectories from primary tumor cells to individual metastases, and determine the origins of the metastasis (pre-
EMT vs. post-EMT cells). Further, we will develop genetic barcoding mice (MARC:CRISPR:PyMT) for lineage
tracing of spontaneous metastatic cells and assessing the contributions of the EMT program to metastasis.
Impact: Resolving the controversies in the field will not only improve our mechanistic understanding of tumor
metastasis but also provide novel targ...

## Key facts

- **NIH application ID:** 10052263
- **Project number:** 1R01CA244413-01A1
- **Recipient organization:** WEILL MEDICAL COLL OF CORNELL UNIV
- **Principal Investigator:** Dingcheng Gao
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $506,382
- **Award type:** 1
- **Project period:** 2020-07-17 → 2025-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10052263

## Citation

> US National Institutes of Health, RePORTER application 10052263, To study the EMT contributions in tumor metastasis and chemoresistance by using lineage tracing models (1R01CA244413-01A1). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10052263. Licensed CC0.

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