Related Experiment Video
Updated: Jun 22, 2026
Generation of Genomic Deletions in Mammalian Cell Lines via CRISPR/Cas9
Published on: January 3, 2015
MCF7 breast cancer anabolic capacity reduced with CRISPR/Cas9-mediated stable overexpression of DEPTOR
J William Deaver1, Patrick J Ryan1, Colleen L O'Reilly1
1Department of Kinesiology and Sports Management, Texas A&M University, College Station, Texas, United States.
Abstract:
The hyperactivation of mTOR is a significant contributor to the development and progression of a number of human diseases, including a majority of human cancers. Although there have been many scientific and clinical efforts to reduce the impact of mTOR hyperactivation on downstream cellular metabolism, we aimed to mitigate this hyperactivation through a novel targeted gene edit of the intrinsic mTOR inhibitor, DEP domain containing MTOR interacting protein (DEPTOR), in MCF7 human breast cancer cells. Using publicly available bioinformatics tools, we demonstrate that DEPTOR gene expression is low in breast cancers compared with healthy tissues and that DEPTOR expression predicts overall survival, recurrence-free survival, and distant metastasis-free survival in breast cancer patients. We show that a directed overexpression of DEPTOR protein leads to significant alteration of downstream mTORC1 targets and subsequently reduces overall rates of protein synthesis. In addition, treatment of DEPTOR overexpressing cells with small-molecule DEPTOR inhibitor NSC126405 leads to a reversal of this effect, indicating a direct causal mechanism between DEPTOR protein levels and mTORC1 activation.NEW & NOTEWORTHY We identify DEPTOR as a predictor of mortality in breast cancer and show that precision gene editing to restore DEPTOR expression in breast cancer slows cell growth by inhibiting mTOR activity.
Insights
Restoring DEPTOR expression in breast cancer cells inhibits mTOR activity, slowing cancer cell growth. Low DEPTOR levels predict poor survival, highlighting DEPTOR as a potential therapeutic target for breast cancer.
Area of Science:
- Oncology
- Molecular Biology
- Genetics
Background:
- Hyperactivation of the mechanistic target of rapamycin (mTOR) pathway is implicated in numerous human diseases, particularly cancers.
- DEP domain containing MTOR interacting protein (DEPTOR) is an intrinsic inhibitor of mTOR.
- DEPTOR's role in breast cancer and its therapeutic potential remain underexplored.
Purpose of the Study:
- To investigate the role of DEPTOR in breast cancer progression and its potential as a therapeutic target.
- To assess the impact of restoring DEPTOR expression on mTOR activity and breast cancer cell growth.
- To evaluate DEPTOR expression as a prognostic biomarker in breast cancer patients.
Main Methods:
- Bioinformatic analysis of DEPTOR gene expression in breast cancer tissues versus healthy controls.
- Correlation analysis of DEPTOR expression with patient survival outcomes (overall survival, recurrence-free survival, distant metastasis-free survival).
- Gene editing to overexpress DEPTOR in MCF7 human breast cancer cells and assessment of downstream mTORC1 targets and protein synthesis rates.
- Treatment of DEPTOR-overexpressing cells with a small-molecule DEPTOR inhibitor (NSC126405) to assess reversibility of effects.
Main Results:
- DEPTOR gene expression is significantly lower in breast cancers compared to healthy tissues.
- Lower DEPTOR expression is associated with poorer overall survival, recurrence-free survival, and distant metastasis-free survival in breast cancer patients.
- Overexpression of DEPTOR in MCF7 cells led to reduced mTORC1 signaling and decreased protein synthesis rates.
- Inhibition of DEPTOR in DEPTOR-overexpressing cells reversed the observed effects, confirming a direct link between DEPTOR levels and mTORC1 activity.
Conclusions:
- DEPTOR is a significant predictor of mortality and disease progression in breast cancer.
- Precision gene editing to restore DEPTOR expression effectively inhibits mTOR activity and slows breast cancer cell growth.
- Targeting DEPTOR represents a promising novel therapeutic strategy for breast cancer treatment.
