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Published on: June 27, 2020

Transcriptional profiling identifies cyclin D1 as a critical downstream effector of mutant epidermal growth factor

Susumu Kobayashi1, Takeshi Shimamura, Stefano Monti

  • 1Division of Hematology/Oncology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA.

Cancer Research
|December 6, 2006
PubMed

Insights

Activating mutations in epidermal growth factor receptor (EGFR) drive non-small cell lung cancer (NSCLC). Cyclin D1 reduction by EGFR inhibitors halts proliferation, suggesting it as a therapeutic target in EGFR-mutant NSCLC.

Area of Science:

  • Molecular oncology
  • Cancer genetics
  • Pharmacogenomics

Background:

  • Activating mutations in the epidermal growth factor receptor (EGFR) are key drivers of non-small cell lung cancer (NSCLC) and determine sensitivity to EGFR tyrosine kinase inhibitors.
  • Acquired resistance to EGFR inhibitors, often mediated by the T790M mutation, remains a significant clinical challenge in NSCLC treatment.
  • The precise transcriptional alterations induced by mutant EGFR signaling and subsequent drug treatment are not fully elucidated.

Purpose of the Study:

  • To identify pivotal transcriptional changes in NSCLC cells harboring activating EGFR mutations upon treatment with different EGFR inhibitors.
  • To investigate the role of cyclin D1 in the proliferation of EGFR-mutant NSCLC cells and its response to targeted therapy.
  • To explore cyclin D1 as a potential therapeutic target in EGFR-driven lung tumorigenesis.

Main Methods:

  • Transcriptional profiling of H1975 NSCLC cells (harboring T790M EGFR mutation) treated with gefitinib (resistant) and CL-387,785 (sensitive) to identify differentially expressed genes.
  • Analysis of cyclin D1 transcription and its downstream effects on E2F-responsive genes.
  • Comparison of cyclin D1 expression between EGFR-mutant and wild-type EGFR NSCLC cells and assessment of sensitivity to flavopiridol (a CDK inhibitor).

Main Results:

  • Treatment with the irreversible EGFR inhibitor CL-387,785, but not gefitinib, significantly reduced cyclin D1 transcription in H1975 cells.
  • Reduced cyclin D1 expression correlated with suppressed E2F-responsive genes, indicating proliferation arrest.
  • EGFR-mutant NSCLC cells exhibited higher cyclin D1 expression and were sensitive to flavopiridol, confirming the functional importance of the cyclin D axis.

Conclusions:

  • Cyclin D1 downregulation is an early transcriptional event following effective EGFR inhibition in resistant NSCLC cells.
  • The cyclin D1/E2F pathway plays a crucial role in the proliferation of EGFR-driven NSCLC.
  • Targeting cyclin D1 represents a promising alternative therapeutic strategy for patients with EGFR-mutant NSCLC.

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