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High-throughput Screening for Chemical Modulators of Post-transcriptionally Regulated Genes
Published on: March 3, 2015
Chemical Genetics Screen Identifies COPB2 Tool Compounds That Alters ER Stress Response and Induces RTK Dysregulation
Punit Saraon1, Jamie Snider2, Wiebke Schormann3
1Drug Discovery Program, Ontario Institute for Cancer Research, Ontario, Canada.
Abstract:
Activating mutations in the epidermal growth factor receptor (EGFR) are common driver mutations in non-small cell lung cancer (NSCLC). First, second and third generation EGFR tyrosine kinase inhibitors (TKIs) are effective at inhibiting mutant EGFR NSCLC, however, acquired resistance is a major issue, leading to disease relapse. Here, we characterize a small molecule, EMI66, an analog of a small molecule which we previously identified to inhibit mutant EGFR signalling via a novel mechanism of action. We show that EMI66 attenuates receptor tyrosine kinase (RTK) expression and signalling and alters the electrophoretic mobility of Coatomer Protein Complex Beta 2 (COPB2) protein in mutant EGFR NSCLC cells. Moreover, we demonstrate that EMI66 can alter the subcellular localization of EGFR and COPB2 within the early secretory pathway. Furthermore, we find that COPB2 knockdown reduces the growth of mutant EGFR lung cancer cells, alters the post-translational processing of RTKs, and alters the endoplasmic reticulum (ER) stress response pathway. Lastly, we show that EMI66 treatment also alters the ER stress response pathway and inhibits the growth of mutant EGFR lung cancer cells and organoids. Our results demonstrate that targeting of COPB2 with EMI66 presents a viable approach to attenuate mutant EGFR signalling and growth in NSCLC.
Insights
A novel molecule, EMI66, targets Coatomer Protein Complex Beta 2 (COPB2) to inhibit mutant epidermal growth factor receptor (EGFR) signaling. This approach shows promise for treating non-small cell lung cancer (NSCLC) resistant to current therapies.
Area of Science:
- Oncology
- Molecular Biology
- Drug Discovery
Background:
- Activating mutations in epidermal growth factor receptor (EGFR) drive non-small cell lung cancer (NSCLC).
- Acquired resistance to EGFR tyrosine kinase inhibitors (TKIs) limits treatment efficacy and leads to relapse.
Purpose of the Study:
- To characterize a novel small molecule, EMI66, as a potential therapeutic agent against mutant EGFR NSCLC.
- To elucidate the mechanism of action of EMI66, focusing on its effects on EGFR signaling and cellular pathways.
Main Methods:
- Utilized mutant EGFR NSCLC cell lines and organoids for experimental validation.
- Investigated the effects of EMI66 on receptor tyrosine kinase (RTK) expression, signaling, and protein modifications.
- Assessed the impact of EMI66 and COPB2 knockdown on cellular localization, growth, and endoplasmic reticulum (ER) stress pathways.
Main Results:
- EMI66 attenuates RTK expression and signaling, and alters Coatomer Protein Complex Beta 2 (COPB2) protein mobility.
- EMI66 modifies the subcellular localization of EGFR and COPB2 within the early secretory pathway.
- COPB2 knockdown and EMI66 treatment inhibit mutant EGFR NSCLC cell and organoid growth, impacting RTK processing and ER stress.
Conclusions:
- Targeting COPB2 with EMI66 offers a novel strategy to overcome resistance and inhibit mutant EGFR signaling in NSCLC.
- EMI66 demonstrates therapeutic potential by modulating key cellular pathways involved in cancer progression.
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