Characterizing combination autophagy inhibition and exogenous stress in murine triple negative breast cancer
Public Deposited- Last Modified
- February 26, 2019
- Creator
-
Lawton, Jack
- Affiliation: Gillings School of Global Public Health, Department of Nutrition
- Abstract
- Background:Triple negative breast cancer represents a significant treatment challenge due to its inherent aggressiveness and lack of targetable receptors, consequently generating a need for novel treatment approaches. Autophagy, a self-degradative pathway that provides metabolic substrates and recycles damaged proteins and organelles, has been implicated in supporting cancer survival, progression towards metastasis, and chemotherapeutic resistance. Autophagy inhibition has exhibited weak effects on cancer by itself but provides a quality therapeutic target in combination with agents that exploit autophagy deficient cell vulnerabilities, classically through nutrient or chemotherapeutic stress. However, the success of autophagy inhibition in combination therapies has been shown to be highly tumor type, stage, and oncogene dependent, thus making researching the effect of autophagy and exogenous stress on Triple negative breast cancer an important avenue for continuing autophagy and cancer research. Methods: In order to characterize autophagy deficient metastatic TNBC in vitro, ATG5, an essential autophagy protein, was knocked out using a CRISPR/Cas 9 construct in both a mesenchymal mouse derived TNBC cell dubbed the M-Wnt and in a metastatic line developed from M-Wnt lung metastases, called the metM-Wntlung. Experiments using both Wild-Type and autophagy deficient lines assayed relative growth, energy generation potential, EMT phenotype, and response to stress in the form of chemotherapeutics and nutrient starvation. Results: Relative to their autophagy competent counterparts, Atg5-/- cells showed decreased growth and significantly altered metabolism, displaying high basal energetics but reduced maximum energy production. Autophagy inhibition alone also resulted in downregulation of EMT regulators Twist, Snail, and Slug, and morphologically exhibited signs of an EMT reversion. Growth and metabolic effects were not observed across all exogenous stressors; only serum starvation and doxorubicin treatment appeared to act synergistically with autophagy inhibition to reduce cancer growth. Reactive oxygen species induced by doxorubicin and an inability to balance redox stress via an antioxidant response (NRF2) may underlie synergistic chemotherapy effects. Conclusions: These findings suggest that autophagy inhibition induces broad cellular changes, including metabolic alterations that strengthen specific nutrient and chemotherapeutic treatments. Further investigation of this model in vivo and identification of a molecular target to maximize autophagy inhibition effects have potential to lead to practical, effective adjuvant or neoadjuvant combination therapies.
- Date of publication
- April 2018
- Keyword
- DOI
- Resource type
- Rights statement
- In Copyright
- Advisor
- Hursting, Stephen
- Degree
- Bachelor of Science in Public Health
- Academic concentration
- Nutrition
- Honors level
- Honors
- Degree granting institution
- University of North Carolina at Chapel Hill
- Graduation year
- 2018
- Language
- English
Relations
- Parents:
This work has no parents.
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