Abstract 4139: Prolyl 4-hydroxylase subunit alpha 1 acts as a novel target for lung adenocarcinoma brain metastasis

Abstract Lung cancer is the most lethal cancer worldwide, with a high incidence of distant metastasis. Many lung adenocarcinoma (LUAD) patients experience brain metastasis during the disease process with unfavorable prognosis. Our previous study has discovered that P4HA1 was exclusively upregulated in brain metastatic cells. Through the analysis of single-cell RNA sequencing of LUAD samples, we found that the expression of P4HA1 in brain metastatic tumor cells is higher than that in primary tumor cells. This finding was further confirmed by immunohistochemical staining. Significantly, a strong presence of P4HA1 in primary tumors is associated with a reduced duration of disease-free survival in individuals with LUAD. Overexpression of P4HA1 in A549 and PC9 cell lines significantly increased the incidence of brain metastasis in BALB/c nude mice, whereas knockdown of P4HA1 in high brain metastatic cells significantly decreased the incidence of brain metastasis and reduced the tumor foci in brain with improved survival. Utilization of DHB, a P4HA1 inhibitor, exerts both therapeutic and preventive effects in relieving brain metastases in nude mice. Furthermore, remarkable inhibition of tumor growth by DHB was observed in patient derived xenograft (PDX) models. RNA sequencing analysis demonstrated that the reduction of P4HA1 expression had a substantial impact on cell adhesion and extracellular matrix (ECM)-receptors interactions. Western blotting analysis verified that the decrease in P4HA1 expression led to a drop in the expression of adhesion molecules ICAM1, VCAM1, NCAM1, as well as integrin molecules ITGA2 and ITGA3. Furthermore, when endothelial cells were co-cultured with conditioned medium from tumor cells, it was observed that the expression of the tight junction molecule ZO1 was reduced after co-culturing with conditioned medium from P4HA1 knockdown A549 cells. The results from the in vitro blood-brain barrier (BBB) model and in vivo biofluorescence imaging indicate that P4HA1 promoted brain metastasis of LUAD via modulating the ability of tumor cells to cross the blood-brain barrier. In conclusion, our study reveals that overexpression of P4HA1 promotes metastatic spread to the brain, and targeting P4HA1 could be a promising therapeutic strategy for the treatment of lung adenocarcinoma brain metastasis. Citation Format: Yan He, Zhenyu Luo, Yucheng Dong, Rui Wan, Xue Zhang, Hua Bai, Jie Wang. Prolyl 4-hydroxylase subunit alpha 1 acts as a novel target for lung adenocarcinoma brain metastasis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4139.