Downregulation of GDF15 suppresses ferroptosis and predicts unfavorable prognosis in clear cell renal cell carcinoma

Abstract

Growth differentiation factor 15 (GDF15), a member of the transforming growth factor beta (TGF-β) superfamily, is involved in various pathophysiological processes such as anorexia, obesity, inflammation, and tumorigenesis. However, the role of GDF15 in clear cell renal cell carcinoma (ccRCC) remains poorly understood. Clinical significance of GDF15 in ccRCC as well as other types of human cancers was analyzed using the TCGA PANCAN dataset. Gene Set Enrichment Analysis (GSEA) was used to study the significantly enriched pathways associated with GDF15 expression. qRT-PCR was used to quantitatively assess relative mRNA expression level. Flow cytometry was used to detect cell cycle. CCK-8 assay, colony formation assay, wound healing assay, Transwell migration/invasion assay, and EdU assay were used to comprehensively examine tumor viability and aggressiveness. MDA and iron assays were used to determine ferroptosis-related intracellular changes. We found that GDF15 expression is decreased in renal carcinoma tissue. In 769-p and Caki-1 cells, GDF15 knockdown significantly promoted tumor viability, proliferation, and migration. Conversely, overexpression of GDF15 suppressed cell proliferation and invasion. Results from GSEA suggested that GDF15 might play a crucial role in ferroptosis. We further demonstrated that GDF15 is correlated with intracellular iron and lipid peroxidation MDA in 769-p and Caki-1 cells. In summary, we conclude that GDF15 inhibits migration and invasion of ccRCC cells by regulating ferroptosis. Our study demonstrates that GDF15 downexpression promotes viability and aggressiveness of ccRCC cells by abolishing ferroptosis, which confers unfavorable patient survival outcomes.