title: Curcumin p38-dependently enhances the anticancer activity of valproic acid in human leukemia cells.
abstract: Valproic acid (VPA) is a broad-spectrum inhibitor of histone deacetylase, which has been used in cancer therapy. Recently, the combination of VPA with other anticancer agents has been considered as a useful and necessary strategy to specifically induce anticancer gene expression. Curcumin (Cur) is a promising natural anticancer agent that can specifically regulate the expression of NF-kappaB, bcl-2, and bax in leukemia cells. However, no literature is available on the anticancer effects of the combination of VPA and Cur. Here we show that this combination significantly increases Sp1 binding, histone H3 and H4 acetylation in the promoter region of bax, but not in that of bcl-2. This specifically up-regulates bax expression and leads to HL-60 cell proliferation arrest, sub-G1 DNA accumulation and cell death. Further studies reveal that Cur specifically activates p38 MAPK, an essential factor for Sp1 binding at the bax promoter. Moreover, both inhibition of p38 MAPK and knock-down of bax expression significantly prevent VPA and Cur-induced proliferation arrest and death in HL-60 cells. These results suggest that Cur could p38-dependently promote bax expression and hence enhance the anticancer activity of VPA in human leukemia cells.
authors.affiliation: Department of Hematology, Changhai Hospital, The Second Military Medical University, Shanghai, People's Republic of China.
authors.forename: Jie
authors.initials: J
authors.lastname: Chen
authors.forename: Guiying
authors.initials: G
authors.lastname: Wang
authors.forename: Libing
authors.initials: L
authors.lastname: Wang
authors.forename: Jiuhong
authors.initials: J
authors.lastname: Kang
authors.forename: Jianmin
authors.initials: J
authors.lastname: Wang
mesh_terms: D000107:Acetylation; D000970:Antineoplastic Agents / Q000494:pharmacology*; D001483:Base Sequence; D047369:Chromatin Immunoprecipitation; D003474:Curcumin / Q000494:pharmacology*; D017931:DNA Primers; D004357:Drug Synergism; D005434:Flow Cytometry; D018922:HL-60 Cells; D006801:Humans; D015473:Leukemia, Promyelocytic, Acute / Q000473:pathology*; D034622:RNA Interference; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014635:Valproic Acid / Q000494:pharmacology*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism*
chemical_list: D000970:Antineoplastic Agents; D017931:DNA Primers; D014635:Valproic Acid; D048051:p38 Mitogen-Activated Protein Kinases; D003474:Curcumin