A Functionally Robust Phenotypic Screen that Identifies Drug Resistance-associated Genes Using 3D Cell Culture

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Sun-Young Lee1, Mina J Bissell1

  • 1Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.

Bio-Protocol
|January 29, 2019
PubMed

Insights

A new 3D cell culture assay identifies novel drug resistance mechanisms in cancer. This method advances understanding of resistance to EGFR tyrosine kinase inhibitors (TKI) and aids in discovering new therapeutic targets.

Area of Science:

  • Oncology
  • Molecular Biology
  • Drug Discovery

Background:

  • Drug resistance, particularly to EGFR tyrosine kinase inhibitors (TKI), is a significant challenge in cancer therapy.
  • Traditional 2D cell culture assays for drug resistance lack physiological relevance and do not accurately predict in vivo outcomes.
  • Identifying novel targets and understanding resistance mechanisms are crucial for improving cancer treatment efficacy.

Purpose of the Study:

  • To develop and validate a physiologically relevant 3D cell culture model for identifying drug resistance mechanisms.
  • To discover novel therapeutic targets and intermediates involved in oncogenic signaling pathways contributing to drug resistance.
  • To establish a phenotype-based genetic screen for evaluating drug resistance in cancer.

Main Methods:

  • A genetic screen utilizing a 3D cell culture model with functional endpoints was developed.
  • The assay was performed over 1-1.5 months using a small cDNA library.
  • Phenotypic changes in response to drug treatment were analyzed to identify resistance mechanisms.

Main Results:

  • The 3D culture assay successfully identified five unknown intermediates in the EGFR and PI3K signaling pathways.
  • One novel molecule's role in drug resistance was characterized, demonstrating the assay's potential.
  • The screening method provides a foundation for high-throughput screening of oncogenic signaling pathways.

Conclusions:

  • The developed 3D culture assay is a powerful tool for discovering novel drug resistance mechanisms and therapeutic targets.
  • This approach offers a more physiologically relevant alternative to traditional 2D assays for cancer research.
  • The methodology can be expanded for high-throughput screening to accelerate drug discovery and development in oncology.
Keywords:
3D CultureDrug resistanceEGFR-TKIExtracellular matrixHMT3522Phenotypic screencDNA overexpression library

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