Exploration of Pericyte-Derived Factors Implicated in Lung Cancer Brain Metastasis Protection: A Pilot Messenger RNA Sequencing Using the Blood-Brain Barrier In Vitro Model.

Metastatic brain tumors have poor prognoses and pose unmet clinical problems for the patients. The blood-brain barrier (BBB) implication is supposed to play a major role in brain metastasis. However, the role of pericytes remains to be elucidated in the brain metastasis. This pilot study described the expression profile of interactions between pericytes, endothelial cells, and cancer cells. We applied an in vitro BBB model with rat primary cultured BBB-related cells (endothelial cells and pericytes), and performed the gene expression analyses of pericytes under the lung cancer cells coculture conditions. Pericytes demonstrated inhibition of the cancer cell proliferation significantly (p < 0.05). RNA was extracted from the pericytes, complementary DNA library was prepared, and RNA-seq was performed. The sequence read data were analyzed on the Management and Analysis System for Enormous Reads and Tag Count Comparison-Graphical User Interface platforms. No statistically or biologically significant differentially expressed genes (DEGs) were detected in the explanatory analyses. Lot-specific DEG detection demonstrated significant decreases in the expression of two genes (Wwtr1 and Acin1), and enrichment analyses using Metascape software revealed the inhibition of apoptotic processes in fibroblasts. Our results suggest that the expression profiles of brain pericytes are partially implicated in the prevention of lung cancer metastasis to the brain. Pericytes exerted an anti-metastatic effect in the BBB model, and their neurohumoral factors remain to be elucidated.