Signaling dynamics in coexisting monoclonal cell subpopulations unveil mechanisms of resistance to anti-cancer
Claire E Blanchard1, Alison T Gomeiz1, Kyle Avery1
1School of Systems Biology, George Mason University, 10920 George Mason Circle, Room 2016, Manassas, VA, 20110, USA.
Background:
Tumor heterogeneity is a main contributor of resistance to anti-cancer targeted agents though it has proven difficult to study. Unfortunately, model systems to functionally characterize and mechanistically study dynamic responses to treatment across coexisting subpopulations of cancer cells remain a missing need in oncology.
Methods:
Using single cell cloning and expansion techniques, we established monoclonal cell subpopulations (MCPs) from a commercially available epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer cell line. We then used this model sensitivity to the EGFR inhibitor osimertinib across coexisting cell populations within the same tumor. Pathway-centered signaling dynamics associated with response to treatment and morphological characteristics of the MCPs were assessed using Reverse Phase Protein Microarray. Signaling nodes differentially activated in MCPs less sensitive to treatment were then pharmacologically inhibited to identify target signaling proteins putatively implicated in promoting drug resistance.
Results:
MCPs demonstrated highly heterogeneous sensitivities to osimertinib. Cell viability after treatment increased > 20% compared to the parental line in selected MCPs, whereas viability decreased by 75% in other MCPs. Reduced treatment response was detected in MCPs with higher proliferation rates, EGFR L858R expression, activation of EGFR binding partners and downstream signaling molecules, and expression of epithelial-to-mesenchymal transition markers. Levels of activation of EGFR binding partners and MCPs' proliferation rates were also associated with response to c-MET and IGFR inhibitors.
Conclusions:
MCPs represent a suitable model system to characterize heterogeneous biomolecular behaviors in preclinical studies and identify and functionally test biological mechanisms associated with resistance to targeted therapeutics.
Insights
Tumor heterogeneity drives resistance to targeted cancer therapies. Researchers developed monoclonal cell subpopulations (MCPs) to model and study this resistance, identifying key signaling pathways involved in drug response.
Area of Science:
- Oncology
- Molecular Biology
- Cancer Research
Background:
- Tumor heterogeneity is a significant challenge in developing effective targeted anti-cancer therapies.
- Studying dynamic treatment responses across diverse cancer cell subpopulations requires robust model systems.
Purpose of the Study:
- To establish and utilize a novel model system for investigating tumor heterogeneity and drug resistance in non-small cell lung cancer.
- To functionally characterize the mechanisms underlying differential sensitivity to targeted agents across cancer cell subpopulations.
Main Methods:
- Established monoclonal cell subpopulations (MCPs) from an EGFR-mutant non-small cell lung cancer cell line.
- Assessed osimertinib sensitivity, signaling dynamics via Reverse Phase Protein Microarray, and morphological characteristics of MCPs.
- Pharmacologically inhibited key signaling nodes to identify mechanisms of drug resistance.
Main Results:
- MCPs exhibited significant heterogeneity in osimertinib sensitivity, with some showing increased viability and others decreased viability post-treatment.
- Reduced treatment response correlated with higher proliferation rates, EGFR L858R expression, activated EGFR binding partners, and epithelial-to-mesenchymal transition markers.
- Proliferation rates and EGFR binding partner activation were associated with response to c-MET and IGFR inhibitors.
Conclusions:
- Monoclonal cell subpopulations (MCPs) provide a suitable preclinical model for studying heterogeneous biomolecular behaviors.
- This model system facilitates the identification and functional testing of mechanisms driving resistance to targeted cancer therapeutics.
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