Jiadai Zhai

Guaianolide Sesquiterpene Lactones, a Source To Discover Agents That Selectively Inhibit Acute Myelogenous Leukemia Stem and Progenitor Cells

Small molecules that can selectively target cancer stem cells (CSCs) remain rare currently and exhibit no common structural features. Here we report a series of guaianolide sesquiterpene lactones (GSLs) and their derivatives that can selectively eradicate acute myelogenous leukemia (AML) stem or progenitor cells. Natural GSL compounds arglabin, an anticancer clinical drug, and micheliolide (MCL), are able to reduce the proportion of AML stem cells (CD34⁺CD38⁻) in primary AML cells. Targeting of AML stem cells is further confirmed by a sharp reduction of colony-forming units of primary AML cells upon MCL treatment. Moreover, DMAMCL, the dimethylamino Michael adduct of MCL, slowly releases MCL in plasma and in vivo and demonstrates remarkable therapeutic efficacy in the nonobese diabetic/severe combined immunodeficiency AML models. These findings indicate that GSL is an ample source for chemical agents against AML stem or progenitor cells and that GSL is potentially highly useful to explore anti-CSC approaches.

Sesquiterpene lactones and their derivatives inhibit high glucose-induced NF-κB activation and MCP-1 and TGF-β1 expression in rat mesangial cells.

Diabetic nephropathy (DN) is one of the most common and serious chronic complications of diabetes mellitus, however, no efficient clinical drugs exist for the treatment of DN. We selected and synthesized several sesquiterpene lactones (SLs), and then used the MTT assay to detect rat mesangial cells (MCs) proliferation, ELISA to measure the expression level of monocyte chemoattractant protein-1 (MCP-1), transforming growth factor beta (TGF-β1) and fibronectin(FN), real-time fluorescent quantitative PCR analysis to measure the MCP-1 and TGF-β1 gene expression, western blot to detect the level of IκBα protein and EMSA to measure the activation of nuclear factor kappa B (NF-κB). We discovered that SLs, including parthenolide (PTL), micheliolide (MCL), arglabin, and isoalantolactone (IAL), as well as several synthetic analogs of these molecules, could effectively attenuate the high glucose-stimulated activation of NF-κB, the degradation of IκBα, and the expression of MCP-1, TGF-β1 and FN in rat mesangial cells (MCs). These findings suggest that SLs and their derivatives have potential as candidate drugs for the treatment of DN.

Biomimetic semisynthesis of arglabin from parthenolide.

The semisynthesis of arglabin, an anticancer drug in clinical application, is developed from abundant natural product parthenolide via three steps. Each step in this sequence is highly stereoselective, and the substrate-dependent stereoselectivity in the epoxidation step can be explained by computational calculations. The success of chemical semisynthesis of arglabin suggests that the biosynthesis of arglabin might proceed in a similar pathway.

AOPPs Induce MCP-1 Expression by Increasing ROS-Mediated Activation of the NF-κB Pathway in Rat Mesangial Cells: Inhibition by Sesquiterpene Lactones

Background: Monocyte chemoattractant protein-1 (MCP-1) plays an important role in extracellular matrix accumulation through macrophage recruitment and activation in the development and progression of diabetic nephropathy. Therefore, this study examined whether advanced oxidation protein products (AOPPs) are involved in nuclear factor-κB (NF-κB) activation and MCP-1 mRNA and protein expression in mesangial cells (MCs) and evaluated the effects of derivatives of sesquiterpene lactones (SLs) on AOPP-induced renal damage. Methods: MCP-1 mRNA and protein expression in MCs were determined by quantitative real-time PCR and ELISA, respectively. The level of intracellular reactive oxygen species (ROS) was determined by flow cytometry. The protein expression of tubulin, P47, NF-κB p65, phospho-NF-κB p65, IκB, phospho-IκB, IKKß and phospho-IKKß was evaluated by Western blot. Results: AOPPs caused oxidative stress in MCs and activated the NF-κB pathway by inducing IκBa phosphorylation and degradation. Inhibition of ROS by SOD (ROS inhibitor) blocked the AOPP-mediated NF-κB pathway. Moreover, the inhibition of AOPP-induced overproduction of MCP-1 mRNA and protein was associated with inhibition of IκBa degradation by SLs. Conclusion: AOPPs induce MCP-1 expression by activating the ROS/NF-κB pathway and can be inhibited by SLs. These findings may provide a novel approach to treat inflammatory and immune renal diseases, including diabetic nephropathy.

Micheliolide Derivative DMAMCL Inhibits Glioma Cell Growth In Vitro and In Vivo

Background There is no highly effective chemotherapy for malignant gliomas to date. We found that dimethylaminomicheliolide (DMAMCL), a selective inhibitor of acute myeloid leukemia (AML) stem/progenitor cells, inhibited the growth of glioma cells. Methods The distribution of DMAMCL in brain was analyzed by an ultraperformance liquid chromatography-mass spectrometry (UPLC-MS/MS) system. The anti-tumor evaluations of DMAMCL in vitro were performed by MTT, FACS and RT-PCR. In vivo, the mixture of C6 cells and matrigel was injected into caudatum, and the anti-tumor activity of DMAMCL was evaluated by tumor growth and rat survival. The toxicity of DMAMCL was evaluated by body weight, daily food intake, hematological or serum biochemical analyses, and histological appearance of tissues. Results The IC50 values of DMAMCL against the C6 and U-87MG cell lines in vitro were 27.18 ± 1.89 μM and 20.58 ± 1.61 μM, respectively. DAMMCL down-regulated the anti-apoptosis gene Bcl-2 and increased apoptosis in C6 and U-87MG cells in a dose-dependent manner. In a C6 rat tumor model, daily administration of DMAMCL for 21 days reduced the burden of C6 tumors by 60% to 88% compared to controls, and more than doubled the mean lifespan of tumor-bearing rats. Distribution analysis showed that the DMAMCL concentration was higher in the brain than in plasma. Evaluations for toxicity revealed that oral administration of DMAMCL at 200 or 300 mg/kg once a day for 21 days did not result in toxicity. Conclusions These results suggest that DMAMCL is highly promising for the treatment of glioma.

Epothilone D and its 9-Methyl analogues: combinatorial syntheses, conformation, and biological activities.

Epothilone D (Epo D) and its 9-Methyl conformational analogues were synthesized through a highly efficient combinatorial approach. The fragment E was synthesized in 11 total steps with 6 longest linear steps, and each aldehyde B was prepared via a 3-step sequence. Starting from the common precursor E and a suitable aldehydes B, each target molecule were obtained in only 4 steps. The 9-(S)-epo D and 9-(R)-epo D demonstrated significant difference in inhibition activities against cancer cell lines and in conformational analysis.

Abstract 3350: Inhibition of breast cancer and cancer stem cells via a novel micheliolide analogue CY-9

Proceedings: AACR 102nd Annual Meeting 2011‐‐ Apr 2‐6, 2011; Orlando, FL Natural products that target cancer stem cells (CSCs) have the potential to treat cancers and reduce the occurrence of relapse. The sesquiterpene lactone parthenolide has received much attention for its ability to preferentially target CSCs over their normal equivalents. However, poor pharmacokinetics have severely limited the clinical use of parthenolide, and prompted synthesis of a water soluble analogue, LC-1. Although currently in Phase I trials for disseminated cancers, LC-1 suffers from a short half-life, which could potentially limit its efficacy. In order to identify new sesquiterpene lactones which function similarly to parthenolide and LC-1 but with improved pharmacokinetics, we tested a new micheliolide analogue CY-9 for activity against both breast cancer and CSCs. Using the MTS assay, SUM159 breast cancer cells displayed sensitivity to CY-9 with an IC50 of 5 μM, which is similar to reported inhibitory concentrations of parthenolide. SUM159 cells assayed for Aldefluor expression after a three day treatment with CY-9 (1, 2.5, 5 μM) showed a 27%, 64%, and 83% reduction in their CSC populations, respectively. This CSC depletion was largely reversed in SUM159 cells that were pre-treated with the antioxidant N-Acetyl-Cysteine (NAC) before exposure to CY-9. Inhibition of SUM159 CSC self-renewal after CY-9 treatment was assayed using tumorsphere formation of single SUM159 Aldefluor-positive cells. A seven day treatment of 5 μM CY-9 reduced SUM159 Aldefluor-positive cell tumorsphere formation by 74%. Under drug-free conditions, tumorsphere formation was reduced by 26% in the second passage, but returned to control levels by the third passage. Western blotting also showed that 5 μM CY-9 reduced the levels of nuclear NF-κB. These results demonstrate the effectiveness of our new micheliolide analogue CY-9 at targeting populations of both bulk breast tumor cells and CSCs. The slight reduction in tumorsphere formation under drug-free conditions suggests that inhibition of self-renewal plays a minor role in CY-9s activity against CSCs. Loss of CY-9 activity with cells pre-treated with NAC suggests that the inhibitory effect of CY-9 is partially mediated by its interaction with biologically relevant cysteines and/or ROS generation. Additionally, as NF-κB is vital for defense against cellular stressors such as ROS, depletion of nuclear NF-κB might also explain the observed inhibition with CY-9. Together, these results warrant further study of CY-9 as a potential therapy for breast cancer and CSCs. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3350. doi:10.1158/1538-7445.AM2011-3350