18β-Glycyrrhetinic acid potentiates Hsp90 inhibition-induced apoptosis in human epithelial ovarian carcinoma cells via activation of death receptor and mitochondrial pathway

The Hsp90 inhibition has been shown to induce apoptosis in various cancer cells. The licorice compounds may enhance the anti-cancer drug effect. However, effect of the licorice compounds on the Hsp90 inhibition-induced apoptosis in ovarian cancer cells has not been studied. To assess the ability of 18β-glycyrrhetinic acid to promote apoptosis, we examined whether 18β-glycyrrhetinic acid potentiated the Hsp90 inhibitor-induced apoptosis in the human epithelial ovarian carcinoma cell lines OVCAR-3 and SK-OV-3. Radicicol and geldanamycin induced a decrease in Bid, Bcl-2, Bcl-xL and survivin protein levels, an increase in Bax levels, the mitochondrial transmembrane potential loss, cytochrome c release, activation of caspases (-8, -9, and -3), cleavage of PARP-1, and an increase in the tumor suppressor p53 levels. 18β-Glycyrrhetinic acid enhanced Hsp90 inhibitor-induced apoptosis-related protein activation, nuclear damage, and cell death. The results suggest that 18β-glycyrrhetinic acid may potentiate the Hsp90 inhibition-induced apoptosis in ovarian carcinoma cell lines via the activation of the caspase-8- and Bid-dependent pathways and the mitochondria-mediated cell death pathway, leading to activation of caspases. Combination of Hsp90 inhibitors and 18β-glycyrrhetinic acid may confer a benefit in the treatment of epithelial ovarian adenocarcinoma.     

Discovery of Tumor Markers for Gastric Cancer by Proteomics

Gastric cancer (GC) has a high rate of morbidity and mortality among various cancers worldwide. The development of noninvasive diagnostic methods or technologies for tracking the occurrence of GC is urgent, and searching reliable biomarkers is considered.This study intended to directly discover differential biomarkers from GC tissues by two-dimension-differential gel electrophoresis (2D-DIGE), and further validate protein expression by western blotting (WB) and immunohistochemistry (IHC).Pairs of GC tissues (gastric cancer tissues and the adjacent normal tissues) obtained from surgery was investigated for 2D-DIEG.Five proteins wereconfirmed by WB and IHC, including glucose-regulated protein 78 (GRP78), glutathione s-transferase pi (GSTpi), apolipoprotein AI (ApoAI), alpha-1 antitrypsin (A1AT) and gastrokine-1 (GKN-1). Among the results, GRP78, GSTpi and A1ATwere significantlyup-regulated and down-regulated respectively in gastric cancer patients. Moreover, GRP78 and ApoAI were correlated with A1AT for protein expressions.This study presumes these proteins could be candidates of reliable biomarkers for gastric cancer.     

Suppression of tumor angiogenesis by targeting the protein neddylation pathway

Inhibition of protein neddylation, particularly cullin neddylation, has emerged as a promising anticancer strategy, as evidenced by the antitumor activity in preclinical studies of the Nedd8-activating enzyme (NAE) inhibitor MLN4924. This small molecule can block the protein neddylation pathway and is now in clinical trials. We and others have previously shown that the antitumor activity of MLN4924 is mediated by its ability to induce apoptosis, autophagy and senescence in a cell context-dependent manner. However, whether MLN4924 has any effect on tumor angiogenesis remains unexplored. Here we report that MLN4924 inhibits angiogenesis in various in vitro and in vivo models, leading to the suppression of tumor growth and metastasis in highly malignant pancreatic cancer, indicating that blockage of angiogenesis is yet another mechanism contributing to its antitumor activity. At the molecular level, MLN4924 inhibits Cullin–RING E3 ligases (CRLs) by cullin deneddylation, causing accumulation of RhoA at an early stage to impair angiogenic activity of vascular endothelial cells and subsequently DNA damage response, cell cycle arrest and apoptosis due to accumulation of other tumor-suppressive substrates of CRLs. Furthermore, we showed that inactivation of CRLs, via small interfering RNA (siRNA) silencing of its essential subunit ROC1/RBX1, recapitulates the antiangiogenic effect of MLN4924. Taken together, our study demonstrates a previously unrecognized role of neddylation in the regulation of tumor angiogenesis using both pharmaceutical and genetic approaches, and provides proof of concept evidence for future development of neddylation inhibitors (such as MLN4924) as a novel class of antiangiogenic agents.     

Stratification in French Guiana: Cerambycid Beetles Go Up When Rains Come Down

When tropical rain forest insect species are associated with a particular season or forest stratum, it can imply tolerance for heat and drought—or moisture dependence; attributes that may predict their responses to global climate change. In French Guiana (1995–1996), wood‐boring cerambycid beetles made a seasonal shift in stratum. During the dry season, ground stratum bait branches were densely colonized, but during the rainy season almost all cerambycids emerged from canopy stratum branches. Because the same substrate was available at both levels, abiotic factors probably influenced branch selection. In this study, cerambycids were reared at the same site (2007–2008) to determine if the seasonal shift recurred. Microclimate data (temperature, relative humidity, and wind speed) were collected with portable weather meters to test the hypothesis that microclimate would be similar at ground stratum during the dry season, and at canopy stratum during the rainy season. The seasonal shift in stratum did recur; many cerambycid individuals (56%) belonged to species classified as ‘seasonal shifters’. Temperatures in the preferred microhabitats were intermediate, but relative humidity remained high during the rainy season (regardless of stratum) and it was windier in the canopy (regardless of season). The shifters preferentially colonized branches at moderate mean temperatures (23.0–24.3°C) and high mean relative humidities (91.3–100%). Shifters were considered season and stratum generalists because they were reared at both strata and were present in both seasons, but they may actually track a narrow microclimate window. Should the regional climate become warmer and drier, it would probably favor species currently restricted to the dry season or canopy stratum.     

PRODUCTION OF 7-DEOXY-OKADAIC ACID BY A NEW CALEDONIAN STRAIN OF PROROCENTRUM LIMA (DINOPHYCEAE)

7-Deoxy-okadaic acid and okadaic acid were identified as the major diarrhetic shellfish poisoning (DSP) toxins produced by a New Caledonian strain of Prorocentrum lima Ehrenberg. Dinophysistoxin-1 was not produced by this strain. The cellular concentrations of 7-deoxy-okadaic acid were about one tenth that of okadaic acid and were maximal (∼1.4 pg·cell ^{− 1}) during the stationary growth phase of batch culture. Autolytic hydrolysis of cell extracts did not increase the concentrations of 7-deoxy-okadaic acid, whereas okadaic acid production increased more than 4-fold, indicating that 7-deoxy-okadaic acid, unlike okadaic acid, is not directly derived from large sulfated precursors. 7-Deoxy-okadaic acid could be detected by liquid chromatography-selected reaction monitoring mass spectrometry, HPLC-fluorescence detection after derivatization with 9-anthryldiazomethane (ADAM), and inhibition of protein phosphatases. The solvent washes currently used for solid-phase clean-up of ADAM-derivatized DSP samples elute derivatized 7-deoxy-okadaic acid, indicating that the current sample clean-up protocol for HPLC-fluorescence detection would miss any contamination by this toxin.     

A single amino acid substitution in the movement protein enables the mechanical transmission of a geminivirus

Begomoviruses of the Geminiviridae are usually transmitted by whiteflies and rarely by mechanical inoculation. We used tomato leaf curl New Delhi virus (ToLCNDV), a bipartite begomovirus, to address this issue. Most ToLCNDV isolates are not mechanically transmissible to their natural hosts. The ToLCNDV-OM isolate, originally identified from a diseased oriental melon plant, is mechanically transmissible, while the ToLCNDV-CB isolate, from a diseased cucumber plant, is not. Genetic swapping and pathological tests were performed to identify the molecular determinants involved in mechanical transmission. Various viral infectious clones were constructed and successfully introduced into Nicotiana benthamiana, oriental melon, and cucumber plants by Agrobacterium-mediated inoculation. Mechanical transmissibility was assessed via direct rub inoculation with sap prepared from infected N. benthamiana. The presence or absence of viral DNA in plants was validated by PCR, Southern blotting, and in situ hybridization. The results reveal that mechanical transmissibility is associated with the movement protein (MP) of viral DNA-B in ToLCNDV-OM. However, the nuclear shuttle protein of DNA-B plays no role in mechanical transmission. Analyses of infectious clones carrying a single amino acid substitution reveal that the glutamate at amino acid position 19 of MP in ToLCNDV-OM is critical for mechanical transmissibility. The substitution of glutamate with glycine at this position in the MP of ToLCNDV-OM abolishes mechanical transmissibility. In contrast, the substitution of glycine with glutamate at the 19th amino acid position in the MP of ToLCNDV-CB enables mechanical transmission. This is the first time that a specific geminiviral movement protein has been identified as a determinant of mechanical transmissibility.