Scavenger Receptor A1 Prevents Non-Small Cell Lung Cancer Metastasis by Suppressing Macrophage Serum Amyloid A1 Expression

ABSTRACT: Metastasis is the key determinant of poor prognosis for advanced-stage NSCLC patients. Although an important contributor to metastasis is cross-talk between tumor-associated macrophages (TAMs) and tumor cells, its regulation is not fully understood. Expressed primarily in macrophages, scavenger receptor A1 (SR-A1) has been associated with lung tumorigenesis. Here, the mechanistic basis for the involvement of SR-A1 in lung cancer prognosis was investigated using population genetics, transcriptomics, and functional analyses. SR-A1 genetic variants were investigated for possible association with survival of advanced-stage NSCLC patients in the Harvard Lung Cancer Study cohort. Two SNPs (rs17484273, rs1484751) in SR-A1 were significantly associated with poor overall survival of NSCLC patients. Further, data from The Cancer Genome Atlas showed a considerable down-regulation of SR-A1 in lung tumor tissues. The association of SR-A1 with prognosis was validated in animal models in the context of lung cancer metastasis. Macrophages derived from SR-A1 knockout mice accelerated metastasis in a lung cancer mouse model. On the other hand, tumor cell seeding, migration, and invasion as well as macrophage accumulation in lung cancer tissue were enhanced in SR-A1 knockout mice. Furthermore, SR-A1 deficiency promoted up-regulation of serum amyloid A1 (SAA1) in macrophages, which appeared to be mediated by MAPK/Ikappa-B/NF-kappaB signaling. Further, SAA1 exposure promoted tumor cell invasion and macrophage migration in vitro and in vivo, but these effects were blocked by administration of an anti-SAA1 antibody. These findings suggest that SR-A1 may suppress lung cancer metastasis by down-regulating SAA1 production in macrophages.

ORGANISM(S): Mus musculus

PROVIDER: GSE83473 | GEO | 2019/06/16

REPOSITORIES: GEO