CD44+ Lung Cancer Stem Cell-derived Vascular Pericytes Cause Brain Metastases through GPR124-mediated Trans-endothelial Migration [I]

Brain metastasis of lung cancer causes high mortality, but the exact mechanisms underlying the metastasis remain unclear. Here we report that vascular pericytes derived from CD44+ lung cancer stem cells (CSCs) in lung adenocarcinoma (ADC) potently cause brain metastases through GPR124-mediated trans-endothelial migration (TEM). CD44+ CSCs in the perivascular niche generate the majority of vascular pericytes in lung ADC. CSC-derived pericyte-like cells (Cd-pericytes) exhibit remarkable TEM capacity to effectively intravasate into vessel lumina, survive in the circulation, extravasate into the brain parenchyma, and then de-differentiate into tumorigenic CSCs to form metastases. Moreover, Cd-pericytes uniquely express GPR124, a G-protein-coupled receptor. GPR124 mediates through Wnt7-β-Catenin activation to enhance TEM capacity of Cd-pericytes for intravasation and extravasation, two critical steps during tumor metastasis. Furthermore, selective disruption of Cd-pericytes, GPR124 or Wnt7-β-Catenin signaling markedly reduced brain and liver metastases of lung ADC. Our findings uncover an unappreciated cellular and molecular paradigm driving tumor metastasis. Lung adenocarcinoma cell derived pericytes were transduced with non-targeting shRNA or shRNA targeting GPR124 genes. The gene expressions were analized by high throughput RNA sequencing.