Curcumin: a bioactive compound with molecular targets for human malignancies

Cancer is the second leading cause of death in the world and one of the major public health problems. Curcumin has anticancer activity including inducing apoptosis and inhibiting proliferation and invasion of tumours by suppressing a variety of cellular signalling pathways. It also possesses anti-tumour activity on different human cancers such as breast cancer, lung cancer, head and neck squamous cell carcinoma, prostate cancer, and brain tumours. In vitro and in vivo trails, curcumin inhibits tumour development and metastasis by inhibiting many pathways that regulate signalling in malignant cells, including Ras, p53, extracellular signal-regulated kinases (ERK), Wnt-protein kinase B (Akt), MAPKs, and PI3K. Curcumin can also inhibit IKK, EGFR, -catenin, cyclin D1, tumour necrosis factor (TNF), and anti-apoptotic genes such as Bcl-X and Bcl-2 along with downregulating nuclear transcription factors like NF-kappa B, which reduces the formation of pro-inflammatory cytokines like chemokines, TNF-, Interleukins and IL-1, IL-2, IL-6, IL-8, IL-12.Abbreviations: AP-1, activated protein 1; Bax, BCL-2-associated X protein; Bcl-XL, B-cell leukaemia extralarge; Cdc, cell division cycle; COX, cyclooxygenase; CY, cytochrome; DPPC, dipalmitoylphosphatidylcholine; EGFR, epidermal growth factor receptor; eIF, eukaryotic initiation factors; FOX, Forkhead box; FPTase, farnesyl protein transferase; HIF, hypoxia-inducible factor; histone deacetylase inhibitors, HLJ, DnaJ-like heat shock protein; Hsp, heat shock proteins; IL, interleukin; miRNA, micro ribonucleic acid; MMC, mitomycin-C; mTOR, mammalian target of rapamycin; NF-kappa B, nuclear transcription factor-kappa-B; PG, prostaglandins; PKB, protein kinase B; Ras, reticular activating system; TargOncol, human small cell lung cancer cell lines; TGF, transforming growth factor; TNF, tumour necrosis factor; TP, thymidine phosphorylase; TPA3, 12-O-tetradecanoylphorbol-13-acetate; u-PA, urokinase-type plasminogen activator; VEGF, vascular endothelial growth factors; XIAP, Xlinked inhibitor of apoptosis