2-hydroxy-3-methylanthraquinone and Leukemia

The herb of Hedyotis diffusa Willd (H. diffusa Willd), an annual herb distributed in northeastern Asia, has been known as a traditional oriental medicine for the treatment of cancer. Recently, Chinese researchers have discovered that two anthraquinones isolated from a water extract of H. diffusa Willd showed apoptosis-inducing effects against cancer cells. However, the cellular and molecular mechanisms responsible for this phenomenon are poorly understood. The current study determines the role of mitogen-activated protein kinases (MAPK) in human leukemic U937 cells apoptosis induced by 2-hydroxy-3-methylanthraquinone from H. diffusa. Our results showed that 2-hydroxy-3-methylanthraquinone decreased phosphorylation-ERK1/2 (p-ERK1/2), and increased p-p38MAPK, but did not affect expressions of p-JNK1/2 in U937 cells. Moreover, treatment of U937 cells with 2-hydroxy-3-methylanthraquinone resulted in activation of caspase-3. Furthermore, PD98059 (ERK1/2 inhibitor) significantly enhanced 2-hydroxy-3-methylanthraquinone-induced apoptosis in U937 cells, whereas caspase-3 inhibitor or SB203580 (p-p38MAPK inhibitor), decreased apoptosis in U937 cells. Taken together, our study for the first time suggests that 2-hydroxy-3-methylanthraquinone is able to enhance apoptosis of U937 cells, at least in part, through activation of p-p38MAPK and downregulation of p-ERK1/2. Moreover, the triggering of caspase-3 activation mediated apoptotic induction.

Topics: Anthraquinones; Apoptosis; Caspase 3; Down-Regulation; Hedyotis; Humans; Leukemia; MAP Kinase Signaling System; Medicine, East Asian Traditional; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; p38 Mitogen-Activated Protein Kinases; Phosphorylation; U937 Cells

Numerous studies have shown that Hedyotis diffusa WILLD (H. diffusa) could promote apoptosis in several cancer cell lines. However, the cellular and molecular mechanisms responsible for this phenomenon are still poorly understood. The current study determines the role of Fas/FasL in THP-1 cell apoptosis induced by 2-hydroxy-3-methylanthraquinone from H. diffusa.. THP-1 cells were treated with 2-hydroxy-3-methylanthraquinone from H. diffusa. The effect on the cell viability of THP-1 cells was evaluated using the trypan blue assay, and cell apoptosis was measured by Giemsa staining and flow cytometry. Protein expression was assayed using the Western blot method.. Our results showed that 2-hydroxy-3-methylanthraquinone from H. diffusa induced THP-1 cell apoptosis in a time- and dose-dependent manner. Apoptosis was associated with a more prominent induction expression of Fas/FasL, DR4 and TRAIL in a time-dependent manner. Moreover, treatment of THP-1 cells with 2-hydroxy-3-methylanthraquinone from H. diffusa resulted in activation of caspase-8.. For the first time, our study suggests that 2-hydroxy-3-methylanthraquinone from H. diffusa is able to enhance apoptosis of THP-1 cells, at least in part, through activation of Fas/FasL, DR4 and TRAIL. Moreover, triggering of caspase-8 activation mediated apoptotic induction.

Topics: Anthraquinones; Apoptosis; Blotting, Western; Caspase 8; Cell Line, Tumor; Dose-Response Relationship, Drug; Enzyme Activation; Fas Ligand Protein; fas Receptor; Flow Cytometry; Hedyotis; Humans; Leukemia