title: 6-C-methyl flavonoids isolated from Pinus densata inhibit the proliferation and promote the apoptosis of the HL-60 human promyelocytic leukaemia cell line.
abstract: Three structurally related 6-C-methyl flavonoids isolated from Pinus densata, including 5,4'-dihydroxy-3,7,8-trimethoxy-6-C-methylflavone (PD1), 5,7,4'-trihydroxy-3,8-dimethoxy-6-C-methylflavone (PD2), and 5,7,4'-trihydroxy-3-methoxy-6-C-methylflavone (PD3), were tested for their ability to inhibit the proliferation and promote the apoptosis of the HL-60 human leukaemia cell line. Cytotoxicity assays in the HL-60 human cancer cell line demonstrated that 5,4'-dihydroxy-3,7,8-trimethoxy-6-C-methylflavone exhibited the most potent cytotoxicity of the three structurally related 6-C-methyl flavonoids. 5,4'-Dihydroxy-3,7,8-trimethoxy-6-C-methylflavone inhibited the proliferation of HL-60 cells in a dose-dependent manner with an IC₅₀ of 7.91 µM (48 h treatment). Furthermore, 5,4'-dihydroxy-3,7,8-trimethoxy-6-C-methylflavone-induced apoptosis was associated with mitochondrial membrane disruption and cytochome c release. Flow cytometry analyses revealed an increase in the hypodiploid population in 5,4'-dihydroxy-3,7,8-trimethoxy-6-C-methylflavone-treated HL-60 cells. Treatment with a concentration of 5,4'-dihydroxy-3,7,8-trimethoxy-6-C-methylflavone that induced apoptosis activated caspase-3 but did not activate caspase-1. A caspase-3 inhibitor (Ac-DEVD-CHO), but not a caspase-1 inhibitor (Ac-YVAD-CHO), reversed the cytotoxic effects of 5,4'-dihydroxy-3,7,8-trimethoxy-6-C-methylflavone in HL-60 cells. These data demonstrated that 5,4'-dihydroxy-3,7,8-trimethoxy-6-C-methylflavone effectively induced the apoptosis of HL-60 cells and exhibited significant anticancer activity via the mitochondrial caspase-3-dependent apoptosis pathway.
authors.affiliation: School of Pharmacy, Second Military Medical University, Shanghai, China.
authors.forename: Rongcai
authors.initials: R
authors.lastname: Yue
authors.forename: Bo
authors.initials: B
authors.lastname: Li
authors.forename: Yunheng
authors.initials: Y
authors.lastname: Shen
authors.forename: Huawu
authors.initials: H
authors.lastname: Zeng
authors.forename: Bo
authors.initials: B
authors.lastname: Li
authors.forename: Hu
authors.initials: H
authors.lastname: Yuan
authors.forename: Yiren
authors.initials: Y
authors.lastname: He
authors.forename: Lei
authors.initials: L
authors.lastname: Shan
authors.forename: Weidong
authors.initials: W
authors.lastname: Zhang
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D020170:Caspase 1 / Q000378:metabolism*; D053148:Caspase 3 / Q000378:metabolism*; D061945:Caspase Inhibitors / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005419:Flavonoids / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D005434:Flow Cytometry; D018922:HL-60 Cells; D006801:Humans; D015473:Leukemia, Promyelocytic, Acute / Q000188:drug therapy; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D028223:Pinus / Q000737:chemistry*; D018515:Plant Leaves / Q000737:chemistry; D018547:Plant Stems / Q000737:chemistry
chemical_list: D061945:Caspase Inhibitors; D005419:Flavonoids; D053148:Caspase 3; D020170:Caspase 1