Multiomic Analysis of Lung Tumors Defines Pathways Activated in Neuroendocrine Transformation

Area of Science:

• Oncology
• Cancer Biology
• Molecular Pathology

Background:

• Lineage plasticity, particularly the transformation of lung adenocarcinoma (LUAD) to small cell lung cancer (SCLC), is a significant mechanism of treatment resistance.
• Understanding the molecular underpinnings of this neuroendocrine (NE) transformation is crucial but limited by scarce pre/post-transformation clinical samples.

Purpose of the Study:

• To elucidate the molecular mechanisms driving NE transformation in lung cancer.
• To identify genomic contexts, molecular pathways, and potential therapeutic vulnerabilities associated with LUAD to SCLC transformation.

Main Methods:

• Comprehensive characterization of combined LUAD/SCLC tumors and pre/post-transformation samples using genomic, epigenomic, transcriptomic, and proteomic analyses.
• Investigation of specific genomic alterations, such as 3p chromosome arm loss.
• Evaluation of pathway involvement, including PRC2, PI3K/AKT, and NOTCH.
• Assessment of pharmacologic inhibition of the PI3K/AKT pathway in patient-derived xenograft models.

Main Results:

• NE transformation is primarily driven by transcriptional reprogramming rather than accumulating mutations.
• Frequent loss of the 3p chromosome arm is associated with NE transformation.
• Enhanced expression of genes in the PRC2 complex, PI3K/AKT, and NOTCH pathways was observed.
• Inhibition of the PI3K/AKT pathway demonstrated potential in delaying tumor growth and NE transformation in an EGFR-mutant model.

Conclusions:

• The study defines a novel molecular landscape of NE transformation in lung cancer, highlighting transcriptional reprogramming as the key driver.
• Identified genomic contexts and pathway dysregulations provide insights into LUAD-to-SCLC transformation.
• Targeting the PI3K/AKT pathway represents a potential therapeutic vulnerability for NE transformation in lung cancer.