Programmed cell death protein 4 (PDCD4)

Programmed cell death protein 4 (PDCD4) is a highly conserved, non-enzymatic, RNA-binding tumor suppressor protein that acts primarily by inhibiting cap-dependent translation through direct binding to the eukaryotic initiation factor 4A (eIF4A). PDCD4 is widely expressed in immune and non-immune cells and plays a critical role in regulating cell proliferation, apoptosis, and immune responses. PDCD4 suppresses tumorigenesis and tumor progression by blocking translation of growth-promoting and anti-apoptotic mRNAs. Loss of PDCD4 function, whether by genetic downregulation, increased degradation, or suppression by microRNA-21, is observed in various human cancers and is associated with increased cell proliferation, invasion, and metastasis. Beyond oncology, PDCD4 is increasingly recognized for its roles in metabolic diseases (such as diabetes and atherosclerosis), inflammation, and tissue fibrosis, primarily via regulation of metabolic and inflammatory gene expression. Despite its significance as a tumor suppressor, there are currently no clinically approved drugs that directly target PDCD4, but its expression status serves as a valuable prognostic and potentially predictive biomarker in cancer and other diseases.

Other names

Programmed cell death factor 4Pdcd4

Inhibition of PDCD4 (e.g., by microRNA-21) can promote tumorigenesis by lifting suppression on translation of oncogenic mRNAs. Upregulation or delivery of PDCD4 (e.g., via experimental gene therapy, small molecules preventing its degradation) suppresses proliferation and promotes apoptosis in cancer models. Downstream effects involve inhibition of cap-dependent translation and modulation of AP-1 activity.