An HLA-G/SPAG9/STAT3 axis promotes brain metastases

Area of Science:

• Oncology
• Molecular Biology
• Cancer Metastasis Research

Background:

• Brain metastases (BM) are the most frequent brain tumors in adults.
• Current BM therapies have limited efficacy and survival outcomes, necessitating deeper understanding.
• The early stages of brain metastasis are critical for lesion establishment.

Purpose of the Study:

• To analyze the transcriptional profiles of brain metastasis initiating cells (BMICs) at premetastatic and established macrometastatic stages.
• To identify common molecular signatures of early-stage BMICs across different primary cancers.
• To elucidate the functional role of identified molecular pathways in brain metastasis.

Main Methods:

• RNA sequencing of premetastatic and macrometastatic BMICs from lung, breast, and melanoma.
• Comparative transcriptomic analysis to identify shared signatures.
• Functional studies to validate the role of HLA-G in the metastatic cascade.

Main Results:

• A common transcriptomic signature distinguishes premetastatic BMICs from non-premetastatic counterparts across lung, breast, and melanoma.
• Premetastatic BMICs show increased expression of HLA-G.
• An HLA-G/SPAG9/STAT3 axis was identified to promote the establishment of brain metastatic lesions.

Conclusions:

• The molecular landscape of premetastatic BMICs offers insights into early brain metastasis.
• HLA-G plays a crucial role in the early stages of brain metastasis establishment via the SPAG9/STAT3 axis.
• Targeting premetastatic BMIC pathways, such as the HLA-G axis, may lead to novel preventive or therapeutic strategies for brain metastases.