Study of effects of micheliolide on ovarian cancer cell lines and its mechanism / 中华妇产科杂志

Objective To study the roles of micheliolide on ovarian cancer cells. Methods Firstly, human ovarian cancer cell lines HeyA8, SKOV3 and A2780/DDP were treated with different concentration of micheliolide (0.25, 0.5, 1, 2.5, 5, 10, 20, 50 μmol/L) for 72 hours, then methyl thiazolyl tetrazolium (MTT) assay was used wo detect the growth of the human ovarian cancer cell lines and the stongest inhibited cell line were selected for the following test. Secondly, after HeyA8 cell line was treated with different concentration (5, 10, 20μmol/L) of micheliolide for 24 hours, the HeyA8 cell apoptosis was measured byflow cytometry. Thirdly, the expression of RelA mRNA in HeyA8 cell was detected through real-time PCR, the expressions of nuclear factor κB(NF-κB)signal pathway related protein RelA and the activited cysteinyl aspartate specific proteinase (caspase-9) were detected by western blot analysis. Results (1) The growth of HeyA8, SKOV3 and A2780/DDP cells were all significantly inhibited after being treated with different concentration of micheliolide for 72 hours and the roles of inhibition were all concentration dependant (P<0.05). The half maximal inhibitory concentration (IC50) of HeyA8, SKOV3 and A2780/DDP were (9.8±2.2), (12.0±2.1) and (12.8±1.8)μmol/L, respectively. We chose HeyA8 cell to do the following expreriments because of its best inhibited effect. (2) After HeyA8 cell was treated with micheliolide of different concentrations, as the concentration increased (20 and 0μmol/L, for example), the apoptosis rate of HeyA8 cell raised from (7.2±1.0)%to (17.4±1.1)%, the percentage of survived cells reduce from (92.8 ± 1.3)% to (82.6 ± 1.4)%,and the relative mRNA level of RelA decreased from 1.00 ± 0.13 to 0.18 ± 0.00 (P<0.01); furthermore, the expression of RelA protein was weaken and the activited caspase-9 protein expression was increased gradually. Conclusions Micheliolide plays a significantly inhibited role in HeyA8, SKOV3 and A2780/DDP cells. The inhibited role of micheliolide inovarian cancer cells might through inhibiting nuclear factor-kappa B (NF-кB) signaling pathway, and inducing the expression of activited caspase-9 protein to promoting apoptosis of HeyA8 cell.

Effect of ADAR1 on the development of MLL-AF9 induced murine AML / 中华血液学杂志

<p><b>OBJECTIVE</b>To establish the ADAR1 (adenosine deaminase that act on RNA 1) knockout MLL-AF9 acute myeloid leukemia (AML) mouse model, and to preliminarily investigate the effects of ADAR1 deletion on the development of AML.</p><p><b>METHODS</b>The lineage⁻ (Lin⁻) cells of ER-CreADAR1(lox/lox) mice and their ADAR1(lox/lox) counterparts were enriched by magnetic activated cell sorting (MACS) and then transduced with retrovirus carrying MSCV- MLL/AF9-IRES-GFP fusion gene. The efficiency of transduction was detected by flow cytometry, and equal number of GFP⁺ cells were transplanted into lethally irradiated recipient mice. The recipient mice were treated with tamoxifen at 48 hours after transplantation to induce ADAR1 knockout and divided into following groups: experimental group (ER-Cre;ADAR1(lox/lox)+tamoxifen), control groups ((1)ER-Cre;ADAR1(lox/lox)+vechile, (2)ADAR1(lox/lox)+tamoxifen, (3)ADAR1(lox/lox)+vechile). The percentage of GFP⁺ cells in peripheral blood was examined at 10, 15 and 20 days respectively after transplantation and the survival of the recipient mice was observed. In vitro study, ER-Cre;ADAR1(lox/lox) and ADAR1(lox/lox) AML cells were cultured and the apoptosis rates of these cells 48 hours after 4-hydroxytamoxifen treatment were examined.</p><p><b>RESULTS</b>The ADAR1 deletion MLL-AF9 AML mouse model was successfully established. Deletion of ADAR1 could decrease the percentage of GFP⁺ cells in the peripheral blood and significantly prolong the survival rate of recipient mice（P<0.05）. In vitro study showed that the cultured total cell number, percentage of GFP⁺ cells decreased and the apoptosis rate of AML cells increased.</p><p><b>CONCLUSION</b>Ablation of ADAR1 could delay the progression of AML in recipient mice. ADAR1 plays a critical role in the development and maintenance of murine MLL-AF9 AML.</p>

Effect of PD0332991 on biological activity of hematopoietic stem cells in mice / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate the effect of PD0332991 (C24H29N7O2) on cell cycle, apoptosis, differentiation and self-renewal of hematopoietic stem cells (HSC) in mice.</p><p><b>METHODS</b>The self renewal ability of HSCs was measured by cobblestone forming cell assay (CAFC). The colony-forming cell (CFC) assay was used to quantify the changes of numbers and functions of HPC after the treatment of the compound. The expressions of self-renewal regulation genes, cell cycle-related genes, apoptosis-related genes were measured by real-time PCR. The cell cycle status and apoptosis of HSC and HPC were analyzed by flow cytometry.</p><p><b>RESULTS</b>There were obvious changes in cell cycle regulation between control and PD0332991 groups. HSCs in G1 phase increased significantly from 76.3% to 89.5% after treatment of PD0332991 (P<0.05) while cells in S, G2 and M phase reduced from 20.5% to 7.3% (P<0.05). HPCs in G1 phase also increased from 74% to 87.4% after treatment of PD0332991 (P<0.05) while cells in S, G2 and M phase reduced from 25.54% to 11.6% (P<0.05). The apoptotic fractions between control and PD0332991 groups had no statistical difference (P>0.05). After cultured with PD0332991, the expression levels of cell cycle genes CDK1, CyclinA2, CyclinF, p18, p19 and p27 decreased by 58.77%, 66.35%, 56.33%, 62.18%, 32.28% and 36.53% respectively, while expression of CDK7 increased by 27.27% (P<0.05). No visible expression difference was observed in apoptosis and self-renew related genes. After treatment of PD0332991, the self-renewal ability of HSC decreased significantly. There were almost no CFCs in PD0332991 group in CAFC assay. Similarly, the frequency of CFCs was dramatically lower in PD0332991 group.</p><p><b>CONCLUSION</b>These results suggested that PD0332991 affected HSC/HPC from mice mainly through inhibiting the cell cycle rather than apoptosis. It also suggested that CDK4/6 might play a key role in the regulation of HSC/HPC.</p>

Construction,expression and in vitro specific killing activity of a recombinant fusion protein:anti-CD20Fab-LDM / 中国药理学通报

Aim To construct and express anti-CD20Fab-LDP,generate anti-CD20Fab-LDM and identify its biological activity.Methods PCR and overlapping PCR were used to construct anti-CD20Fab-LDP.DNA sequence was analyzed by the Terminus of Dideoxy Nucleotide.The product was purified by affinity chromatography and analyzed by Western blot and its antigen-binding activity was examined by FACS.Specific killing activity in vitro of anti-CD20Fab-LDM was analyzed by MTT.Results The data of DNA sequence showed that anti-CD20Fab-LDP was correct.The fusion protein was recovered in high yield(up to 4 mg·L~(-1))after proteinG purification.The fusion protein could bind to Raji cells(CD20+),and similar affinity data were obtained with anti-CD20Fab.Anti-CD20Fab-LDP showed potent cytotoxicity to Raji cells with IC_(50) values of 0.9×10~(-10) mol·L~(-1).Conclusions Anti-CD20Fab-LDP with high level expression was successfully obtained and could bind to Raji cells cells.Anti-CD20Fab-LDM showed specific killing activity to Raji cells in vitro.

Construction and expression of disulphide stabilized anti-CD3/anti-Pgp diabody / 生物工程学报

We constructed and expressed an anti-CD3/anti-Pgp (P-glycoprotein) diabody previously. However, the two chains of diabody are associated non-covalently, resulting in being capable of dissociating. The aim of this study is to enhance the stability of the diabody. We introduced cysteine residues into the CD3 or Pgp V-domain to covalently lock the two chains together. The disulphide crosslinked diabody were expressed by Escherichia coli (E. coli) 16C9 and purified by a cation exchange column and an anti-Etag affinity chromatography. The purified proteins were verified through SDS-PAGE. Flow cytometry (FCM) was used to analyse the binding properties, competitive binding capacity and stability in vitro. The dsPpg-diabody failed to form disulphide bond properly. The designed disulphide bridge between the different chains of dsCD3-diabody was formed correctly. FCM demonstrated the dsCD3-diabody has specific antigen binding activity, the same binding activity and competitive binding activity as its parent diabody. The dsCD3-diabody retained the full activity even after 72 h incubation at 37 degrees C in human serum, in contrast, the parent diabody began to lose activity after only 1 h and lose all its activity 24 hours later. The induced disulphide bond in the CD3 V-domain effectively enhanced the stability of anti-CD3/anti-Pgp diabody. The method of stabilizing a diabody by introducing a disulphide bond into is practical.

Design and discovery of novel small-molecule inhibitor of CDK9 / 中国药理学通报

Aim To look for novel small-molecule inhibitors of CDK9 through structure-based virtual screening and biological activity determination.Methods Homology modeling of CDK9 was based on the 3-D structure of other cyclin-dependent kinase family members,and then virtual screening by DOCK(molecular docking)of database of small molecule was carried on.MTT method was used in inhibition of tumor cell growth in vitro,while Western blot was used for further study of molecular mechanisms.Results From the top 1000 compounds with the best DOCK energy score,27 compounds were selected for biological assay based on the diversity of chemical structure and functional group.12 of 27 selected compounds showed significantly inhibition activity on tumor cell proliferation,and only one compound in 12 with half-maximum inhibition concentration(IC50)values less than 20 ?mol?L-1 named C-21 was selected for further molecular mechanism study.The western blotting data showed C-21 compound could effectively inhibit CDK9 from phosphorylating large subunit C-terminal of RNA polymerase Ⅱ in a dose-dependent manner.Conclusions Through homology modeling,virtual screening by computer,determination of biological activity and experimental studies of molecular mechanism,a new promising lead compound targeted for CDK9 was found and confirmed.