Recurrent WNT pathway alterations are frequent in relapsed small cell lung cancer

Area of Science:

• Oncology
• Molecular Biology
• Genetics

Background:

• Small cell lung cancer (SCLC) frequently relapses with chemoresistant disease.
• The underlying molecular mechanisms of SCLC chemoresistance are not well understood.

Purpose of the Study:

• To investigate the molecular alterations associated with chemoresistance in relapsed SCLC.
• To identify potential therapeutic targets for overcoming SCLC chemoresistance.

Main Methods:

• Whole-exome sequencing of paired diagnostic and relapse SCLC tumor samples.
• Analysis of RNA sequencing data to assess gene expression profiles.
• Functional studies using SCLC cell lines to investigate WNT signaling in chemoresistance.

Main Results:

• Relapsed SCLC samples show copy number alterations (e.g., ABCC1 gains, MYCL deletions) and mutations in WNT signaling regulators (CHD8, APC).
• An ASCL1-low expression subtype and WNT pathway activation are enriched in relapsed SCLC.
• WNT signaling activation, induced by APC knockdown, confers chemoresistance in SCLC cell lines.

Conclusions:

• Activation of WNT signaling is a significant mechanism contributing to chemoresistance in relapsed SCLC.
• Targeting WNT signaling may represent a viable therapeutic strategy for patients with relapsed SCLC.