Single-Cell Transcriptome Identifies Drug-Resistance Signature and Immunosuppressive Microenvironment in Metastatic...

Area of Science:

• Oncology
• Genomics
• Immunology

Background:

• Small cell lung cancer (SCLC) is a highly metastatic neuroendocrine cancer.
• Understanding the single-cell heterogeneity of metastatic SCLC is crucial for developing effective treatments.
• Current knowledge of SCLC's metastatic landscape and tumor microenvironment is limited.

Purpose of the Study:

• To characterize the inter-patient and intra-tumor heterogeneity of metastatic SCLC at the single-cell level.
• To investigate genomic alterations and immune infiltration in metastatic SCLC.
• To compare the immune microenvironment of SCLC with non-small cell lung cancer (NSCLC).

Main Methods:

• Single-cell transcriptome analysis of 24,081 cells from lymph node metastases of seven SCLC patients.
• Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) for sample collection.
• Whole exome sequencing (WES) for genomic alterations and comparison with public scRNA-seq data for immune infiltration.

Main Results:

• Malignant SCLC cells exhibit distinct inter-patient and intra-tumor heterogeneity based on ASCL1 and NEUROD1 expression.
• High FZD8 expression in the WNT pathway correlates with drug resistance in malignant cells.
• SCLC presents a unique immunosuppressive tumor microenvironment compared to NSCLC, with attenuated MHC-I presentation and impaired NK cell function (high TGFBR2 expression).

Conclusions:

• Metastatic SCLC displays significant cellular heterogeneity, impacting treatment strategies.
• Unique immune evasion mechanisms, including impaired NK cell antitumor activity, are identified in SCLC.
• Findings suggest novel therapeutic avenues for SCLC, potentially involving immune checkpoint blockade and targeting WNT pathway genes.