title: Gallic acid induces G₀/G₁ phase arrest and apoptosis in human leukemia HL-60 cells through inhibiting cyclin D and E, and activating mitochondria-dependent pathway.
abstract: Gallic acid (GA) induces apoptosis in different types of cancer cell lines. In this study, we investigate the apoptotic effects induced by GA in human promyelocytic leukemia HL-60 cells, and clarify the underlying mechanism. Our results showed that GA reduced the viability of HL-60 cells in a dose- and time-dependent manner. GA led to G(0)/G(1) phase arrest in HL-60 cells through promoting p21 and p27 and inhibiting the levels of cyclin D and cyclin E. GA caused DNA damage and fragmentation in HL-60 cells as assayed using DAPI staining and Comet assay. Flow cytometric analysis revealed that GA increased Ca(2+) levels and reduced the mitochondrial membrane potential (ΔΨ(m)) in HL-60 cells. Apoptotic protein expressions were determined by Western blotting. The results indicated that GA-mediated apoptosis of HL-60 cells mainly depended on mitochondrial pathway, by promoting the release of cytochrome c, apoptosis-inducing factor (AIF) and endonuclease G (Endo G) and by up-regulating the protein expression of Bcl-2-associated X protein (BAX), caspase-4, caspase-9 and caspase-3. In addition, GA also activated the death receptor-dependent pathway by enhancing the protein expressions of fatty acid synthase (FAS), FAS ligand (FASL), caspase-8 and BCL-2 interacting domain (BID). We determined the mRNA expression of the gene levels of these proteins by real-time PCR. The results showed that GA-mediated apoptosis of HL-60 cells mainly depended on up-regulation of the mRNA of caspase-8, caspase-9, caspase-3, AIF and Endo G. In conclusion, GA-induced apoptosis occurs through the death receptor and mitochondria-mediated pathways. The evaluation of GA as a potential therapeutic agent for treatment of leukemia seems warranted.
authors.affiliation: The School of Chinese Medicine for Post-baccalaureate, I-Shou University, Kaohsiung 824, Taiwan, ROC.
authors.forename: Ru-Duan
authors.initials: RD
authors.lastname: Yeh
authors.forename: Jung-Chou
authors.initials: JC
authors.lastname: Chen
authors.forename: Tung-Yuan
authors.initials: TY
authors.lastname: Lai
authors.forename: Jai-Sing
authors.initials: JS
authors.lastname: Yang
authors.forename: Chun-Shu
authors.initials: CS
authors.lastname: Yu
authors.forename: Jo-Hua
authors.initials: JH
authors.lastname: Chiang
authors.forename: Chi-Cheng
authors.initials: CC
authors.lastname: Lu
authors.forename: Su-Tso
authors.initials: ST
authors.lastname: Yang
authors.forename: Chien-Chih
authors.initials: CC
authors.lastname: Yu
authors.forename: Shu-Jen
authors.initials: SJ
authors.lastname: Chang
authors.forename: Hui-Yi
authors.initials: HY
authors.lastname: Lin
authors.forename: Jing-Gung
authors.initials: JG
authors.lastname: Chung
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D001483:Base Sequence; D020552:Comet Assay; D056741:Cyclin D / Q000037:antagonists & inhibitors*; D019927:Cyclin E / Q000037:antagonists & inhibitors*; D017931:DNA Primers; D005434:Flow Cytometry; D016193:G1 Phase / Q000187:drug effects*; D005707:Gallic Acid / Q000494:pharmacology*; D018922:HL-60 Cells; D006801:Humans; D008928:Mitochondria / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D016192:Resting Phase, Cell Cycle / Q000187:drug effects*
chemical_list: D056741:Cyclin D; D019927:Cyclin E; D017931:DNA Primers; D005707:Gallic Acid