Abstract
Adipocytokines have gained significant attention in the scientific community over the past few decades. They are a family of enzymes, hormones, growth factors, proteins, and other bioactive molecules that are important regulators of many processes. Adipocytokines are predominantly produced by preadipocytes and mature adipocytes to act through a network of autocrine, paracrine, and endocrine pathways. Leptin (LEP) is the first adipocytokine discovered that has a role in modulating adiposity and has been shown to exert pleiotropic effects on many metabolic pathways through the leptin receptors (LEPRs). LEP has pro-tumoral roles; it promotes angiogenesis, proliferation, survival of tumor cells, and inhibits apoptosis. To exercise its role in tumorigenesis, LEP-LEPR signaling and epithelial-mesenchymal transitions (EMTs) play a significant role. LEP is an oncogenic factor mainly due to its proinflammatory and proangiogenic effects. In angiogenesis, LEP acts directly as an endothelial growth factor or indirectly through cellular pathways, such as STAT3/ERK1/2, JAK2/STAT3, MAPK/ERK, PI3K/AKT, p38, p53, MAPK, and Wnt/β-catenin.