Yanna Cheng

Genome shuffling improves production of cellulase by Penicillium decumbens JU-A10

Aims:  Improvement of cellulase production of Penicillium decumbens by genome shuffling of an industrial catabolite‐repression‐resistant strain JU‐A10 with its mutants.

Reversal effect of a macrocyclic bisbibenzyl plagiochin E on multidrug resistance in adriamycin-resistant K562/A02 cells

Plagiochin E is a new macrocyclic bisbibenzyl compound isolated from Marchantia polymorpha. In the previous studies, we reported that when combined with fluconazole, plagiochin E had synergetic effects against the resistant strain of Candida albicans. Herein, we examined the reversal effect of plagiochin E on multidrug resistance in adriamycin-induced resistant K562/A02 cells and the parental K562 cells. Its cytotoxicity and reversal effects on multidrug resistance were assessed by MTT (3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyl-tetrazolium bromide) assay. Apoptosis percentage of cells was obtained from Annexin V/fluorescein isothiocyanate (FITC) and propridium iodide (PI) double-staining. The effects of plagiochin E on P-glycoprotein activity were evaluated by measuring rhodamine 123 (Rh123)-associated mean fluorescence intensity and P-glycoprotein expression on the basis of the flow cytometric technology, respectively. The results showed that plagiochin E ranging from 2 to 12 mug/ml had little cytotoxicity against K562/A02 cells. When combined with adriamycin, it significantly promoted the sensitivity of K562/A02 cells toward adriamycin through increasing intracellular accumulation of adriamycin in a dose-dependent manner. Further study demonstrated that the inhibitory effect of plagiochin E on P-glycoprotein activity was the major cause of increased stagnation of adriamycin inside K562/A02 cells, indicating that plagiochin E, as a new class of mutidrug resistance inhibitor, may effectively reverse the multidrug resistance in K562/A02 cells via inhibiting expression and drug-transport function of P-glycoprotein.

Protective effects of Salvia plebeia compound homoplantaginin on hepatocyte injury.

Salvia plebeia R. Br is a traditional Chinese herb which has been considered as an inflammatory mediator used for treatment of many infectious diseases including hepatitis. Previously, the compound homoplantaginin was isolated in our group. Hence, we evaluated the protective effects of homoplantaginin on hepatocyte injury. Homoplantaginin displayed an antioxidant property in a cell-free system and showed IC(50) of reduction level of DPPH radical at 0.35 microg/ml. In human hepatocyte HL-7702 cells exposed to H(2)O(2), the addition of 0.1-100 microg/ml of homoplantaginin, which did not have a toxic effect on cell viability, significantly reduced lactate dehydrogenase (LDH) leakage, and increased glutathione (GSH), glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) in supernatant. In vivo assay, we employed the model of Bacillus Calmette-Guérin (BCG)/lipopolysaccharide (LPS)-induced hepatic injury mice to evaluate efficacy of homoplantaginin. Homoplantaginin (25-100mg/kg) significantly reduced the increase in serum alanine aminotranseferase (ALT) and aspartate aminotransferase (AST), decreased the levels of tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 (IL-1). The same treatment also reduced the content of thiobarbituric acid-reactive substances (TBARS), elevated the levels of GSH, GSH-Px and SOD in hepatic homogenate. The histopathological analysis showed that the grade of liver injury was ameliorated with reduction of inflammatory cells and necrosis of liver cells in homoplantaginin treatment mice. These results suggest that homoplantaginin has a protective and therapeutic effect on hepatocyte injury, which might be associated with its antioxidant properties.

Marchantin C, a novel microtubule inhibitor from liverwort with anti-tumor activity both in vivo and in vitro.

Microtubules are long-standing targets in cancer chemotherapy. Previously, we reported that marchantin C triggers apoptosis of human tumor cells. We show here that marchantin C induced cell cycle arrest at G(2)/M phase in A172 and HeLa cells. In addition, marchantin C decreased the quantity of microtubules in a time- and dose-dependent manner in these cells. Exposure of purified bovine brain tubulin to marchantin C inhibited polymerization of gross tubulin in vitro. Moreover, marchantin C potently suppressed the growth of human cervical carcinoma xenografts in nude mice. Marchantin C-treated xenografts showed decreased microtubules, Bcl-2 and increased cyclin B1, Bax, caspase-3, indicating that marchantin C possess the same ability to induce microtubules depolymerization and tumor cell apoptosis in tumor-bearing mice as in vitro. In conclusion, marchantin C is a novel microtubule inhibitor that induces mitotic arrest of tumor cells and suppresses tumor cell growth, exhibiting promising antitumor therapeutic potential.

Des-γ-carboxy prothrombin stimulates human vascular endothelial cell growth and migration

Des-γ-carboxy prothrombin (DCP) is an aberrant prothrombin produced by hepatocellular carcinoma (HCC) cells. Serum and tissue DCP expressions are thought to reflect the biological malignant potential of HCC. However, the role of DCP in the development of angiogenesis is not well understood. Herein, we report the effects of DCP on growth and migration of human vascular endothelial cells. DCP significantly stimulated the proliferation of HUVEC (ECV304) cells in a dose and time dependent manner, as measured by the MTT assay. A continuous rapid migration of ECV304 cells was observed in the presence of DCP measured by the scratch wound assay. The continuous rapid invasive activity, measured by transwell chamber assay also showed that DCP increased endothelial cells migration through the reconstituted extracellular matrix (Matrigel). Further, the tube formation of vascular endothelial cells on 3-D Matrigel showed an increased number of branch points of ECV304 cells induced by DCP in a dose dependent manner. The levels of vascular endothelial cell growth-related angiogenic factors and matrix metalloproteinase were also examined. DCP significantly stimulated the expression levels of epidermal growth factor receptor (EGFR), vascular endothelial growth factor (VEGF), and matrix metalloproteinase (MMP)-2 (latent and active). Together, these data suggest that DCP is a novel type of vascular endothelial growth factor that possesses potent mitogenic and migrative activities in angiogenesis of HCC.

Anti-metastatic and anti-angiogenic activities of sulfated polysaccharide of Sepiella maindroni ink.

A previous study demonstrated that SIP-SII, a sulfated Sepiella maindroni ink polysaccharide, suppressed the invasion and migration of cancer cells via the inhibition of the proteolytic activity of matrix metalloproteinase-2 (MMP-2). Therefore, this study investigated the anti-metastatic effect of SIP-SII in vivo. SIP-SII (15 and 30 mg/kg d) markedly decreased B16F10 pulmonary metastasis in mice models by 85.9% and 88.0%, respectively. Immunohistochemistry showed that SIP-SII decreased the expression of the intercellular adhesion molecule 1 (ICAM-1) and basic fibroblast growth factor (bFGF) in lung metastasis nodules. In addition, SIP-SII inhibited neovascularization in chick chorioallantoic membrane assay at 0.08-2 mg/mL. In the in vitro experiments, SIP-SII (0.8-500 μg/mL) significantly decreased the protein and mRNA expression of ICAM-1 and bFGF in SKOV3 and EA.hy926 cells, respectively. These results suggested that SIP-SII might suppress melanoma metastasis via the inhibition of the tumor adhesion mediated by ICAM-1 and the angiogenesis mediated by bFGF, as well as resulting in depression of the invasion and migration of carcinoma cells.

Hematopoietic effects and mechanisms of Fufang e׳jiao jiang on radiotherapy and chemotherapy-induced myelosuppressed mice.

ETHNOPHARMACOLOGICAL RELEVANCE Fufang e׳jiao jiang (FEJ), which has been widely used in clinic to replenish qi (vital energy) and nourish blood, is a famous traditional Chinese medicine formula made up of Colla corii asini (donkey-hide gelatin prepared by stewing and concentrating from the hide of Equus asinus Linnaeus.), Radix codonopsis pilosulae (the root of Codonopsis pilosula (Franch.) Nannf.), Radix ginseng rubra (the steamed and dried root of Panax ginseng C.A. Mey.), Fructus crataegi (the fruit of Crataegus pinnatifida Bunge) and Radix rehmanniae preparata (the steamed and sun dried tuber of Rehmannia glutinosa (Gaertn.) Libosch. ex Fisch. & C.A. Mey.). The present study aimed to investigate the hematopoietic effects of FEJ on myelosuppressed mice induced by radiotherapy and chemotherapy systematically and to explore the underlying hematopoietic regulation mechanisms. METHODS The myelosuppressed mouse model was induced by (60)Co radiation, cyclophosphamide and chloramphenicol. FEJ was then administered by i.g. at the dosages of 5, 10, or 20 mL/kg·d for 10d. The numbers of blood cells from peripheral blood and bone marrow nucleated cells (BMNC) were counted. Body weight and the thymus and spleen indices were also measured. The numbers of hemopoietic progenitor cells and colony-forming unit-fibroblast (CFU-F) were measured in vitro. The ratio of hematopoietic stem cells (HSC) in BMNC, cell cycle and apoptosis of BMNC were determined by flow cytometry. The histology of femoral bone was examined by H&E staining. The levels of transforming growth factor-β (TGF-β), tumor necrosis factor-α (TNF-α), erythropoietin (EPO), granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-3 (IL-3) and interleukin-6 (IL-6) in serum were measured by ELISA. IL-1β, IL-3, IL-6 mRNA levels in spleen were detected by real-time quantitative PCR (RT-qPCR). In addition, bone marrow stromal cells (BMSC) were cultured in vitro followed by treatment with different doses of FEJ (2.5, 5, 10 μL/mL) for 48 h. Then the levels of cytokines (IL-6, SCF, GM-CSF) in the conditioned media and their mRNA levels in BMSC were determined by ELISA and RT-qPCR, respectively. RESULTS FEJ could significantly increase the numbers of peripheral blood cells and BMNC, and reverse the loss of body weight and the atrophy of thymus and spleen in a dose-dependent manner. The quantities of hemopoietic progenitor cells and CFU-F in bone marrow were also significantly increased in a dose-dependent manner after FEJ administration. A high-dose FEJ of 20 mL/kg·d could significantly increase the ratio of HSC in BMNC, promote bone marrow cells entering the proliferative cycle phase (S+G2/M) and prevent cells from proceeding to the apoptotic phase. FEJ could also improve the femoral bone marrow morphology. Furthermore, FEJ could increase the levels of GM-CSF and IL-3 and reduce the level of TGF-β in serum, and enhance the expressions of IL-1β and IL-3 mRNA in spleen. Lastly, the levels of cytokines (IL-6, SCF, GM-CSF) in the conditioned media and their mRNA levels in BMSC were elevated after treatment with FEJ. CONCLUSIONS FEJ was clearly confirmed to promote the recovery of bone marrow hemopoietic function in a myelosuppressed mouse model, which may be attributed to (i) improving bone marrow hematopoietic microenvironment; (ii) facilitating the cell proliferation and preventing BMNC from apoptosis; (iii) stimulating the expressions of IL-1β, IL-3, IL-6, SCF and GM-CSF and inhibiting the expression of TGF-β.

Riccardin D, a novel macrocyclic bisbibenzyl, induces apoptosis of human leukemia cells by targeting DNA topoisomerase II

SummaryWe studied the effect of riccardin D, a macrocyclic bisbibenzyl, which was isolated from the Chinese liverwort plant, on human leukemia cells and the underlying molecular mechanism. Riccardin D had a significant antiproliferative effect on human leukemia cell lines HL-60, K562 and its multidrug resistant (MDR) counterpart K562/A02 cells, but showed no effect on the topoisomerase-II-deficient HL-60/MX2 cells, as measured by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay. The pBR322 DNA relaxation assay revealed that riccardin D selectively inhibited the activity of topoisomerase II (topo II). The suppression of topo II activity by riccardin D was stronger than that of etoposide, a known topo II inhibitor. After treatment with riccardin D, nuclear extracts of leukemia K562 and K562/A02 cells left the majority of pBR322 DNA in a supercoiled form. Further examination showed that riccardin D effectively induced HL-60, K562 and K562/A02 apoptosis as evidenced by externalization of phosphatidylserine and formation of DNA ladder fragments. The activation of cytochrome c, caspase-9, caspase-3 and cleaved poly ADP-ribose polymerase (PARP) was also enhanced, as estimated by Western blot analysis. By contrast, riccardin D was unable to induce apoptosis in the topoisomerase-II-deficient HL-60/MX2 cells, indicating that the induction of apoptosis by riccardin D was due to the inhibition of topo II activity. In addition, riccardin D was able to significantly decrease P-glycoprotein (P-gp) expression in K562/A02 cells. Taken together, our data demonstrate that riccardin D is a novel DNA topo II inhibitor which can induce apoptosis of human leukemia cells and that it has therapeutic potential for both regular and MDR strains of leukemia cells.

Des-gamma-carboxy prothrombin increases the expression of angiogenic factors in human hepatocellular carcinoma cells

AIMS Des-gamma-carboxyl prothrombin (DCP) is a serum protein produced by hepatocellular carcinoma (HCC) cells. The aim of this study was to evaluate the angiogenic activity of DCP in HCC cells. MAIN METHODS The proliferation of HCC cells was measured by 3-[4, 5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide (MTT) assay. The growth of HCC cells was also evaluated in vivo by using the xenografts in nude mice. The enzyme-linked immunosorbent assay (ELISA) was employed to measure the levels of angiogenic factors in supernatant of cell culture. The expression of angiogenic factors was examined by Western blot analysis and immunohistochemical staining. KEY FINDINGS DCP displayed the stimulation of HCC cell growth in a dose (5-80 ng/ml) and time (24-96 h) dependent manner. The increase of cell growth was also observed in nude mice bearing well-established, palpable HepG2 and SMMC-7721 xenografts after 2 weeks administration of DCP. HCC cell growth was accompanied by the elevated levels of angiogenic factors. The levels of vascular endothelial growth factor (VEGF), transforming growth factor-alpha (TGF-alpha) and basic fibroblast growth factor (bFGF) in supernatant of SMMC-7721 cells were increased from 47, 126, and 60 pg/10(6) cells/24 h to 400, 208, and 298 pg/10(6) cells/24 h, respectively, after 72 h incubation with 80 ng/ml of DCP. The results of Western blot analysis and immunohistochemical staining of HCC xenografts also showed the significant increase of VEGF, TGF-alpha, and bFGF in HCC cells. SIGNIFICANCE These results provide the information that DCP is a type of growth factor in progression of HCC.

Inhibition of angiogenesis involves in anticancer activity of riccardin D, a macrocyclic bisbibenzyl, in human lung carcinoma

Riccardin D is a novel macrocyclic bisbibenzyl compound extracted from Chinese liverwort plant Dumortiera hirsuta. Our previous studies showed that riccardin D is a DNA topo II inhibitor and has therapeutic potential for treatment of cancers. In this combined in vitro and in vivo study, we examined the inhibitory effects of riccardin D on tumor angiogenesis and the subsequent effect of anticancer activity was evaluated. Incubation with riccardin D weakly inhibited the proliferation of human umbilical vascular endothelial cells (HUVEC) as estimated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The scratch wound experiment showed that riccardin D effectively decreased the motility and migration of HUVEC cells. Riccardin D inhibited the formation of capillary tube as demonstrated by decrease of branch points formed by HUVEC cells on 3-D Matrigel. We examined the levels of angiogenic factors including vascular endothelial growth factor (VEGF), VEGF receptor 2, epidermal growth factor receptor (EGF receptor), and matrix metalloproteinase (MMPs) in HUVEC cells. The expressions of VEGF, phospho-VEGF receptor 2, EGF receptor and MMP-2 were significantly reduced by riccardin D as estimated by Western blot assay and real-time quantitative PCR analysis. The decrease of VEGF was also detected in riccardin D-treated human lung cancer H460 cells. The anticancer activity of riccardin D was then evaluated in a mouse model in which riccardin D delayed the growth of H460 xenografts without obvious toxicity to animals after three weeks injection. To evaluate the role of antiangiogenesis of riccardin D in mice, CD34 immunohistochemical staining was employed to analyze the mean vascular density in H460 xenograft tissues. The number of blood vessels was significantly decreased after riccardin D treatment. These results suggest that riccardin D display the inhibitory effect on growth of human lung carcinoma cells and that the inhibition of angiogenesis may involve in anticancer activity of riccardin D.