wogonin and Leukemia

Chronic lymphocytic leukemia is a malignancy of mature B cells that strongly depend on microenvironmental factors, and their deprivation has been identified as a promising treatment approach for this incurable disease. Cytokine array screening of 247 chronic lymphocytic leukemia serum samples revealed elevated levels of tumor necrosis factor (TNF) receptor-1 which were associated with poor clinical outcome. We detected a microenvironment-induced expression of TNF receptor-1 in chronic lymphocytic leukemia cells

Topics: Adoptive Transfer; Animals; Coculture Techniques; Flavanones; Humans; Leukemia; Leukemia, Lymphocytic, Chronic, B-Cell; Lymph Nodes; Mice; Receptors, Tumor Necrosis Factor; Receptors, Tumor Necrosis Factor, Type I; Signal Transduction; Tumor Cells, Cultured; Tumor Microenvironment

A rich flavonoid plant extensively used in traditional medicine is Scutellaria (Lamiaceae). In this study the cytotoxic effects of different extracts of Scutellaria pinnatifida were explored on two different cancer cell lines including K562 and HL-60 and a normal cell line. Also, the role of apoptosis on this toxicity was explored. The cell viability was quantitated by alamarBlue(®) assay. S. pinnatifida could effectively decrease the viability of malignant cells and the CH2Cl2 extract of S. pinnatifida had showed the most cytotoxic effects among other extracts. Apoptosis was confirmed after propidium iodide staining of DNA fragments and detection of the sub-G1 peak in the related flow cytometry histogram of cells. The results of western blot assay showed that CH2Cl2 extract has been able to increase the amount of Bax and cleavage of PARP protein after a 48h contact with cells. Neobaicalein (skullcapflavone II) and wogonin were identified in the extract of S. pinnatifida as the active components. The result of the present study confirmed the putative role of neobaicalein (skullcapflavone II) and wogonin as cytotoxic components in the CH2Cl2 extract of S. pinnatifida.

Topics: Antineoplastic Agents, Phytogenic; Apoptosis; Cell Proliferation; Flavanones; Flavonoids; HL-60 Cells; Humans; K562 Cells; Leukemia; Plant Extracts; Plant Roots; Scutellaria

Wogonin is a flavonoid isolated from Scutellaria baicalensis root and has multiple pharmacological effects, including anticancer effects. Recent studies have shown that wogonin induces cell cycle arrest and reverses multi-drug resistance in the human K562 leukemia cell line. However, its pharmacological function in the apoptosis of leukemia cells remains unknown. Therefore, we hypothesized that wogonin can induce apoptosis in the HL-60 leukemia cell line. In the present study, the HL-60 cells were treated with different doses of wogonin (0-150 µM). Wogonin inhibited the viability of HL-60 cells in a dose-dependent and time-dependent manner. Flow cytometry and analyses of caspase and PARP-1 activation and the Bax/Bcl-2 ratio, demonstrated that the cytotoxic effect of wogonin on HL-60 cells was mediated by caspase-dependent and mitochondrial-dependent apoptosis. Wogonin also induced the expression of certain members of the endoplasmic reticulum (ER) stress pathway (CHOP, GRP94 and GRP78) and the activation of multiple branches of ER stress transducers (IRE1α, PERK-eIF2α and ATF6) in the HL-60 cells. In addition, wogonin reduced the phosphorylation of PI3K and AKT in the HL-60 cells. Furthermore, constitutive activation of AKT induced by adenoviral vectors inhibited the pro-apoptotic effects and ER stress induced by wogonin in the HL-60 cells. In summary, our results indicated that wogonin induced apoptosis and ER stress in HL-60 cells, which was mediated by the inhibition of the PI3K-AKT signaling pathway.

Topics: Animals; Apoptosis; Cell Proliferation; Drug Resistance, Multiple; Endoplasmic Reticulum Chaperone BiP; Endoplasmic Reticulum Stress; Flavanones; Gene Expression Regulation, Leukemic; HL-60 Cells; Humans; Leukemia; Neoplasm Proteins; Oncogene Protein v-akt; Phosphatidylinositol 3-Kinases; Reactive Oxygen Species; Signal Transduction

Damage to DNA can lead to many different acute and chronic pathophysiological conditions, ranging from cancer to endothelial damage. The current study has been initiated to determine whether the flavonoid wogonin can attenuate etoposide-induced oxidative DNA damage and apoptosis in mouse bone marrow cells. We found that oral administration of wogonin before etoposide injection significantly attenuates etoposide-induced oxidative DNA damage and apoptosis in a dose dependent manner. Etoposide induced a significant down-regulation of mRNA expression of the OGG1 repair gene and marked biochemical alterations characteristic of oxidative DNA stress, including increased 8-OHdG, enhanced lipid peroxidation and reduction in reduced glutathione. Prior administration of wogonin ahead of etoposide challenge restored these altered parameters. Importantly, wogonin had no antagonizing effect on etoposide-induce topoisomerase-II inhibition. Conclusively, our study indicates that wogonin has a protective role in the abatement of etoposide-induced oxidative DNA damage and apoptosis in the bone marrow cells of mice via suppression of oxidative DNA stress and enhancing DNA repair through modulation of OGG1 repair gene expression. Therefore, wogonin can be a promising chemoprotective agent and might be useful to avert secondary leukemia and other drug-related cancers in cured cancer patients and medical personnel exposing to the potent carcinogen etoposide.

Topics: Animals; Anticarcinogenic Agents; Antioxidants; Apoptosis; Bone Marrow Cells; DNA Damage; DNA Glycosylases; Dose-Response Relationship, Drug; Etoposide; Flavanones; Gene Expression Regulation; Leukemia; Male; Mice; Micronucleus Tests; Mutagenicity Tests; Oxidative Stress; Random Allocation; RNA, Messenger; Topoisomerase II Inhibitors

We investigate the roles of methoxyl (OCH(3)) and hydroxyl (OH) substitutions at C8 of flavonoids on their apoptosis-inducing activities. Wogonin (Wog) and nor-wogonin (N-Wog) are structurally related flavonoids, and respectively contain an OH and OCH(3) at C8. In leukemia HL-60 cells, N-Wog exhibited more-potent cytotoxicity than Wog according to the MTT and LDH release assays, and the IC(50) values of Wog and N-Wog in HL-60 cells were 67.5 +/- 2.1 and 21.7 +/- 1.5 microM, respectively. Apoptotic characteristics including DNA ladders, apoptotic bodies, and hypodiploid cells accompanied by the induction of caspase 3 protein processing appeared in Wog- and N-Wog-treated HL-60 cells. Interestingly, an increase in intracellular peroxide production was detected in N-Wog- but not Wog-treated HL-60 cells by the DCHF-DA assay, and the reduction of intracellular peroxide by catalase (CAT) induced by N-Wog significantly reduced the N-Wog- but not the Wog-induced cytotoxic effect according to the MTT assay in accordance with the blocking of DNA ladder formation and caspase 3 and PARP protein processing elicited by N-Wog. We further analyzed the effect of six structurally related compounds, including 5-OH, 7-OH, 5,7-diOH, 5,7-diOCH(3), 7,8-diOCH(3), and 7-OCH(3)-8-OH flavones, on apoptosis induction in HL-60 cells. Results suggested that OH at C5 and C7 is essential for both the apoptosis-inducing activity of flavonoids, and OH at C8 may contribute to apoptosis induction ability. Evidence to support a distinct structure-activity relationship in apoptosis induction of flavonoids is provided for the first time in this study.

Topics: Apoptosis; Caspase 3; DNA Fragmentation; Flavanones; Flavones; Flavonoids; HL-60 Cells; Humans; Leukemia; Reactive Oxygen Species; Structure-Activity Relationship

TNFalpha has previously been used in anticancer therapy. However, the therapeutic application of TNFalpha was largely limited due to its general toxicity and the fact that it activates the NF-kappaB-family transcription factors, which are proinflammatory and antiapoptotic. To overcome this problem in vitro, specific NF-kappaB inhibitors or transcription or protein synthesis inhibitors such as actinomycin D and cycloheximide are usually used in combination to increase TNFalpha killing of tumor cells. However, these agents also cause harmful side effects in vivo. We show here that wogonin, derived from the popular Chinese herb Huang-Qin, attenuates NF-kappaB activity by shifting TNFalpha-induced free radical .O(2)(-) to a more reduced nonradical product, H(2)O(2), and thereby sensitizes TNFalpha-resistant leukemia cells to TNFalpha-induced apoptosis. Importantly, wogonin does not affect the viability of normal peripheral blood T cells. Wogonin also sensitizes TRAIL-induced apoptosis. Our data suggest a potential use of wogonin as a TNFalpha or TRAIL adjuvant for cancer treatment. Our data also demonstrate how a herbal compound enhances killing of tumor cells with reduced side effects compared with other treatments.

Topics: Apoptosis; Cell Line, Tumor; Chemotherapy, Adjuvant; Cycloheximide; Dactinomycin; Drug Evaluation, Preclinical; Drugs, Chinese Herbal; Flavanones; Humans; Hydrogen Peroxide; Leukemia; NF-kappa B; Protein Synthesis Inhibitors; Superoxides; T-Lymphocytes; TNF-Related Apoptosis-Inducing Ligand; Tumor Necrosis Factor-alpha