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Updated: May 10, 2026
Rat Model of Blood-brain Barrier Disruption to Allow Targeted Neurovascular Therapeutics
Published on: November 30, 2012
A blood-brain barrier-like vascular gate limits immunotherapy efficacy in neuroendocrine cancers
Yiyun Wang1, Ailing Zhong1, Bo Wang2
1Department of Thoracic Oncology, State Key Laboratory of Biotherapy, Cancer Center, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China.
Abstract:
Small cell lung cancer (SCLC), a highly aggressive neuroendocrine malignancy, exhibits poor response to immunotherapy, and the underlying mechanisms remain unclear. Here, we identify a blood-brain barrier-like vascular gate (BVG) in SCLC, distinct from non-SCLC (NSCLC) and other cancers, composed of tightly connected endothelial cells, a thickened basement membrane, and dense pericyte coverage. Functionally, this blood-brain barrier-like vascular gate restricts immune cell infiltration, contributing to SCLC's immunotherapy resistance. Mechanistically, achaete-scute family basic-helix-loop-helix (bHLH) transcription factor 1 (ASCL1), the master transcription factor of SCLC, is essential for BVG formation by regulating insulin-like growth factor-binding protein 5 (IGFBP5), which activates the IGF1 signaling in endothelial cells. IGFBP5 knockout or treatment with the IGF1R inhibitor OSI-906 enhances CD8+ T cell infiltration and synergizes with anti-PD1 therapy. Furthermore, this ASCL1-IGFBP5-IGF1R axis and the BVG are conserved across multiple neuroendocrine cancers (NECs). Our findings reveal a previously unrecognized vascular gate in NECs and propose novel therapeutic strategies to enhance immunotherapy efficacy in these recalcitrant cancers.
Insights
Small cell lung cancer (SCLC) has a unique vascular gate hindering immunotherapy. Targeting the ASCL1-IGFBP5-IGF1R pathway can improve treatment efficacy in SCLC and other neuroendocrine cancers.
Area of Science:
- Oncology
- Cancer Biology
- Immunotherapy
Background:
- Small cell lung cancer (SCLC) shows poor response to immunotherapy.
- Mechanisms of SCLC immunotherapy resistance are not well understood.
- Neuroendocrine cancers (NECs) often exhibit resistance to current therapies.
Purpose of the Study:
- To identify novel mechanisms contributing to SCLC immunotherapy resistance.
- To investigate the role of vascular structures in immune cell infiltration in SCLC.
- To explore potential therapeutic targets for enhancing immunotherapy in SCLC and NECs.
Main Methods:
- Identification and characterization of a blood-brain barrier-like vascular gate (BVG) in SCLC.
- Investigating the role of achaete-scute family basic-helix-loop-helix transcription factor 1 (ASCL1) in BVG formation.
- Assessing the impact of IGFBP5 modulation and IGF1R inhibition on immune cell infiltration and anti-PD1 therapy response.
- Evaluating the conservation of the identified pathway in other neuroendocrine cancers.
Main Results:
- A distinct blood-brain barrier-like vascular gate (BVG) was identified in SCLC, characterized by specific endothelial cell junctions, basement membrane, and pericyte coverage.
- The ASCL1 transcription factor is crucial for BVG formation, regulating IGFBP5 expression and activating IGF1 signaling in endothelial cells.
- IGFBP5 knockout or IGF1R inhibition (using OSI-906) significantly increased CD8+ T cell infiltration and enhanced the efficacy of anti-PD1 therapy.
- The ASCL1-IGFBP5-IGF1R axis and the BVG were found to be conserved across various neuroendocrine cancers.
Conclusions:
- The study reveals a novel vascular gate (BVG) in SCLC that restricts immune cell infiltration, contributing to immunotherapy resistance.
- The ASCL1-IGFBP5-IGF1R signaling pathway plays a critical role in the formation and maintenance of the BVG.
- Targeting this pathway offers a promising therapeutic strategy to overcome immunotherapy resistance in SCLC and other neuroendocrine cancers.
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