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Updated: Jun 28, 2025
Utilizing Functional Genomics Screening to Identify Potentially Novel Drug Targets in Cancer Cell Spheroid Cultures
Published on: December 26, 2016
ABCG2 and SLC1A5 functionally interact to rewire metabolism and confer a survival advantage to cancer cells under
Jia Shi1, Kirk Pabon1, Rui Ding2
1Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers Biomedical Health Sciences, Rutgers, The State University of New Jersey, Piscataway, New Jersey, USA.
Abstract:
ABCG2, a member of the ABC transporter superfamily, is overexpressed in many human tumors and has long been studied for its ability to export a variety of chemotherapeutic agents, thereby conferring a multidrug resistance (MDR) phenotype. However, several studies have shown that ABCG2 can also confer an MDR-independent survival advantage to tumor cells exposed to stress. While investigating the mechanism by which ABCG2 enhances survival in stressful milieus, we have identified a physical and functional interaction between ABCG2 and SLC1A5, a member of the solute transporter superfamily and the primary transporter of glutamine in cancer cells. This interaction was accompanied by increased glutamine uptake, increased glutaminolysis, and rewired cellular metabolism, as evidenced by an increase in key metabolic enzymes and alteration of glutamine-dependent metabolic pathways. Specifically, we observed an increase in glutamine metabolites shuttled to the TCA cycle, and an increase in the synthesis of glutathione, accompanied by a decrease in basal levels of reactive oxygen species and a marked increase in cell survival in the face of oxidative stress. Notably, the knockdown of SLC1A5 or depletion of exogenous glutamine diminished ABCG2-enhanced autophagy flux, further implicating this solute transporter in ABCG2-mediated cell survival. This is, to our knowledge, the first report of a functionally significant physical interaction between members of the two major transporter superfamilies. Moreover, these observations may underlie the protective role of ABCG2 in cancer cells under duress and suggest a novel role for ABCG2 in the regulation of metabolism in normal and diseased states.
Insights
The ATP-binding cassette transporter ABCG2 interacts with the glutamine transporter SLC1A5, enhancing cancer cell survival under stress by altering metabolism and increasing glutathione synthesis.
Area of Science:
- Cancer Biology
- Molecular Biology
- Cellular Metabolism
Background:
- ABCG2 (ATP-binding cassette transporter G2) is overexpressed in tumors, contributing to multidrug resistance (MDR).
- ABCG2 also confers an MDR-independent survival advantage to tumor cells under stress.
- The precise mechanisms underlying ABCG2's role in stress survival are not fully understood.
Purpose of the Study:
- To investigate the mechanism by which ABCG2 enhances tumor cell survival under stress.
- To identify interacting partners of ABCG2 involved in stress response.
- To elucidate the role of ABCG2-mediated metabolic alterations in cancer cell survival.
Main Methods:
- Co-immunoprecipitation to identify physical interactions between ABCG2 and SLC1A5.
- Measurement of glutamine uptake and metabolic flux analysis.
- Assessment of reactive oxygen species (ROS) levels and glutathione synthesis.
- Knockdown of SLC1A5 and glutamine depletion experiments.
Main Results:
- A physical and functional interaction between ABCG2 and SLC1A5 (solute carrier family 1 member 5) was identified.
- This interaction increased glutamine uptake, glutaminolysis, and shunting of metabolites to the TCA cycle.
- Increased glutathione synthesis and decreased ROS levels were observed, enhancing cell survival under oxidative stress.
- SLC1A5 knockdown or glutamine depletion reduced ABCG2-enhanced autophagy and cell survival.
Conclusions:
- ABCG2 physically and functionally interacts with the glutamine transporter SLC1A5.
- This interaction rewires cancer cell metabolism, promoting survival under stress through enhanced glutaminolysis and glutathione synthesis.
- This study reveals a novel role for ABCG2 in regulating cellular metabolism and stress adaptation, potentially impacting cancer therapy.
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