NDRG1 and lung cancer: Digoxin was found to inhibit HIF-1α effectively to suppress tumor growth [36], and it also prohibited HIF-1α synthesis, vascular endothelial growth factor (VEGF), and N-Myc downregulated gene 1 (NDRG1) in A549 human lung cancer cells to show its cytotoxicity [37]; it suppressed HIF-1α and blood vessel formation in C4-2 castration-resistant prostate tumors [38].