De-An Guo

Paraptosis accompanied by autophagy and apoptosis was induced by celastrol, a natural compound with influence on proteasome, ER stress and Hsp90.

In the present study, we found that celastrol, a natural compound with well‐known apoptosis‐inducing effect, could also induce paraptosis‐like cytoplasmic vacuolization in cancer cell lines including HeLa cells, A549 cells and PC‐3 cells derived from cervix, lung and prostate, respectively. Further study using HeLa cells indicated that the vacuoles induced by celastrol might be derived from dilation of endoplasmic reticulum. And, in celastrol‐treated cells, markers of autophagy such as transformation of microtubule‐associated protein 1 light chain 3 (LC3)I to LC3II and LC3 punctates formation were identified. Interestingly, autophagy inhibitors could not interrupt but enhance the induction of cytoplasmic vacuolization. Furthermore, MAPK pathways were activated by celastrol and inhibitors of MEK and p38 pathways could prevent the formation of cytoplasmic vacuolization. Celastrol treatment also induced G2/M cell cycle arrest and apoptosis in HeLa cells. In conclusion, celastrol induced a kind of paraptosis accompanied by autophagy and apoptosis in cancer cells. The coincidence of apoptosis and autophagy together with paraptosis might contribute to the unique characteristics of paraptosis in celastrol‐treated cells such as the dependence of paraptosis on MAPK pathways and dynamic change of LC3 proteins. Both paraptosis and apoptosis could contribute to the cell death induced by celastrol while autophagy might serve as a kind of survival mechanism. The potency of celastrol to induce paraptosis, apoptosis and autophagy at the same dose might be related to its capability to affect a variety of pathways including proteasome, ER stress and Hsp90. J. Cell. Physiol. 227: 2196–2206, 2012.

Saponins in the genus Panax L. (Araliaceae): a systematic review of their chemical diversity.

The Panax genus is a crucial source of natural medicines that has benefited human health for a long time. Three valuable medicinal herbs, namely Panax ginseng, Panax quinquefolius, and Panax notoginseng, have received considerable interest due to their extensive application in clinical therapy, healthcare products, and as foods and food additives world-wide. Panax species are known to contain abundant levels of saponins, also dubbed ginsenosides, which refer to a series of dammarane or oleanane type triterpenoid glycosides. These saponins exhibit modulatory effects to the central nervous system and beneficial effects to patients suffering from cardiovascular diseases, and also have anti-diabetic and anti-tumor properties. To the end of 2012, at least 289 saponins were reported from eleven different Panax species. This comprehensive review describes the advances in the phytochemistry of the genus Panax for the period 1963-2012, based on the 134 cited references. The reported saponins can be classified into protopanaxadiol, protopanaxatriol, octillol, oleanolic acid, C17 side-chain varied, and miscellaneous subtypes, according to structural differences in sapogenins. The investigational history of Panax is also reviewed, with special attention being paid to the structural features of the six different subtypes, together with their (1)H and (13)C NMR spectroscopic characteristics which are useful for determining their structures and absolute configuration.

Ruggedness and robustness of conversion factors in method of simultaneous determination of multi-components with single reference standard

Single standard to determine multi-components (SSDMC) is a novel and rational method for quality control of botanical products and traditional Chinese medicines (TCMs). However, it is restricted to wide application due to unknown fluctuation in conversion factors when it is performed in different laboratories. To evaluate the fluctuations of conversion factors, we selected Salvia miltiorrhiza as an example to determine three components of tanshinones by SSDMC method. Then ruggedness and robustness test were adopted to comprehensively investigate three kinds of factors that may influence stability of conversion factors, which were related with environmental parametric variables, operational parametric variables and peak measurement parametric variables. Nested-factorial-design was used to perform ruggedness tests. One-variable-at-a-time (OVAT) procedure and Plackett-Burman (PB) design were both used in robustness test. The results showed that stability of conversion factors was principally related with accuracy of wavelength of UV detector, peak measurement parameters and concentration of standard solution. The acceptable range of conversion factors was obtained from robustness test. Our results showed that conversion factors were inevitable to change, but when key parameters were well controlled, the range of its fluctuation was acceptable and the SSDMC method could be used widely in different laboratories.

Cytotoxic triterpenoids from Ganoderma lucidum.

A systematic study of the metabolites in Ganoderma lucidum led to isolation of 43 triterpenoids, six of them (1-6) are hitherto unknown. The structures of the latter were elucidated on the basis of spectroscopic studies and comparison with the known related compounds. All of the compounds were assayed for their inhibitory activities against human HeLa cervical cancer cell lines. Some compounds exhibit significant cytotoxicity, and their structure-activity relationships are discussed.

Osteoclast-derived exosomal miR-214-3p inhibits osteoblastic bone formation.

Emerging evidence indicates that osteoclasts direct osteoblastic bone formation. MicroRNAs (miRNAs) have a crucial role in regulating osteoclast and osteoblast function. However, whether miRNAs mediate osteoclast-directed osteoblastic bone formation is mostly unknown. Here, we show that increased osteoclastic miR-214-3p associates with both elevated serum exosomal miR-214-3p and reduced bone formation in elderly women with fractures and in ovariectomized (OVX) mice. Osteoclast-specific miR-214-3p knock-in mice have elevated serum exosomal miR-214-3p and reduced bone formation that is rescued by osteoclast-targeted antagomir-214-3p treatment. We further demonstrate that osteoclast-derived exosomal miR-214-3p is transferred to osteoblasts to inhibit osteoblast activity in vitro and reduce bone formation in vivo. Moreover, osteoclast-targeted miR-214-3p inhibition promotes bone formation in ageing OVX mice. Collectively, our results suggest that osteoclast-derived exosomal miR-214-3p transfers to osteoblasts to inhibit bone formation. Inhibition of miR-214-3p in osteoclasts may be a strategy for treating skeletal disorders involving a reduction in bone formation.

Microbial transformation of ginsenoside Rb-1 by Acremonium strictum

Preparative-scale fermentation of ginsenoside Rb1 (1) with Acremonium strictum AS 3.2058 gave three new compounds, 12β-hydroxydammar-3-one-20 (S)-O-β-d-glucopyranoside (7), 12β, 25-dihydroxydammar-(E)-20(22)-ene-3-O-β-d-glucopyranosyl-(1→2)-β-d-glucopyranoside (8), and 12β, 20 (R), 25-trihydroxydammar-3-O-β-d-glucopyranosyl-(1→2)-β-d-glucopyranoside (9), along with five known compounds, ginsenoside Rd (2), gypenoside XVII (3), ginsenoside Rg3 (4), ginsenoside F2 (5), and compound K (6). The structural elucidation of these metabolites was based primarily on one- and two-dimensional nuclear magnetic resonance and high-resolution electron spray ionization mass spectra analyses. Among these compounds, 2–6 are also the metabolites of ginsenoside Rb1 in mammals. This result demonstrated that microbial culture parallels mammalian metabolism; therefore, A. strictum might be a useful tool for generating mammalian metabolites of related analogs of ginsenosides for complete structural identification and for further use in pharmaceutical research in this series of compounds. In addition, the biotransformation kinetics was also investigated.

Microtubule-binding natural products for cancer therapy.

Natural products, especially microtubule-binding natural products, play important roles in the war against cancer. From the clinical use of vinblastine in 1961, paclitaxel in 1992, to ixabepilone in 2007, microtubule-binding natural products have continually contributed to the development of cancer therapy. The present review summarizes the development of representative microtubule-binding natural products including agents binding to the colchicine-binding site, the VINCA alkaloid-binding site, the taxane-binding site and other binding sites. Future directions for the development of new anticancer microtubule-binding natural products are discussed. Finding new formulations, new targets and new sources of microtubule-binding natural products may enable more members of this kind of agent to be introduced into the clinic for cancer therapy.

Effects of triterpenes from Ganoderma lucidum on protein expression profile of HeLa cells

To elucidate the cytotoxicity mechanism of Ganoderma triterpenes, a chemoproteomic study using five purified ganoderic acids, ganoderic acid F (GAF), ganoderic acid K (GAK), ganoderic B (GAB), ganoderic acid D (GAD) and ganoderic acid AM1 (GAAM1) was conducted. GAF, GAK, GAB, GAD and GAAM1 treatment for 48 h inhibited the proliferation of HeLa human cervical carcinoma cells with IC(50) values of 19.5+/-0.6 microM, 15.1+/-0.5 microM, 20.3+/-0.4 microM, 17.3+/-0.3 microM, 19.8+/-0.7 microM, respectively. The protein expression profiles of HeLa cells treated with each ganoderic acid at dose of 15 microM for 48 h were checked using two-dimensional electrophoresis (2-DE). The possible target-related proteins of ganoderic acids, i.e. proteins with same change tendency in all five ganoderic acids-treated groups compared with control, were identified using MALDI-TOF MS/MS. Twelve proteins including human interleukin-17E, eukaryotic translation initiation factor 5A (eIF5A), peroxiredoxin 2, ubiquilin 2, Cu/Zn-superoxide dismutase, 14-3-3 beta/alpha, TPM4-ALK fusion oncoprotein type 2, PP2A subunit A PR65-alpha isoform, nucleobindin-1, heterogeneous nuclear ribonucleoprotein K, reticulocalbin 1 and chain A of DJ-1 protein were identified. Ganoderic acids might exert their cytotoxicity by altering proteins involved in cell proliferation and/or cell death, carcinogenosis, oxidative stress, calcium signaling and ER stress.

Tanshinone IIA sodium sulfonate protects against cardiotoxicity induced by doxorubicin in vitro and in vivo.

Although doxorubicin (DXR) is an effective antineoplastic agent; the serious cardiotoxicity mediated by the production of reactive oxygen species has remained a considerable clinical problem. Our hypothesis is that tanshinone IIA sodium sulfonate (TSNIIA-SS), which holds significant affects on cardioprotection in clinic, protects against DXR-induced cardiotoxicity. In vitro investigation on H9c2 cell line, as well as in vivo study in animal model of DXR-induced chronic cardiomyopathy were performed. TSNIIA-SS significantly increased cell viability and ameliorated apoptosis of DXR-injured H9c2 cells using CCK-8 assay and Hoechst 33342 stain respectively. Furthermore, the cardio-protective effects of TSNIIA-SS were confirmed with decreasing ST-interval and QRS interval by electrocardiography (ECG); improving appearance of myocardium with haematoxylin and eosin (H&E) stain; increasing myocardial tensile strength using tension to rupture (TTR) assay and decreasing fibrosis through picric-sirius red staining comparing with those receiving DXR alone. These data have provided the considerable evidences that TSNIIA-SS is a protective agent against DXR-induced cardiac injury.

Interaction of Ganoderma triterpenes with doxorubicin and proteomic characterization of the possible molecular targets of Ganoderma triterpenes

Triterpenes are the main components with cytotoxicity in Ganoderma lucidum, which is used popularly as a complementary treatment for cancer therapy in traditional Chinese medicine. To investigate the possible interaction between chemotherapeutic agents and triterpenes extracted from G. lucidum, the cytotoxicity of doxorubicin (DOX) combined with Ganoderma triterpenes (GTS) or lucidenic acid N (LCN), a purified compound, was examined in HeLa cells. The combinations targeting DOX with GTS or LCN resulted in a synergistic interaction in HeLa cells. Moreover, to identify the molecular targets of GTS, two‐dimensional gel electrophoresis‐based comparative proteomics was carried out and proteins with altered expression levels after GTS treatment in HeLa cells were identified by matrix‐assisted laser desorption/ionization time‐of‐flight tandem mass spectrometry. The results of our proteomic study indicated that the GTS treatment caused regulated expression of 14 proteins, which play important roles in cell proliferation, the cell cycle, apoptosis, and oxidative stress. Flow cytometric analysis confirmed that GTS could induce weak G0–G1 phase arrest and combined use of GTS with DOX could induce apoptosis in cells. Furthermore, GTS enhanced the reactive oxygen species (ROS)‐producing effect of DOX, and a ROS scavenger could affect the synergism between GTS and DOX. In cells with high Ku80 protein expression, the synergism between GTS and DOX was also partly affected. Importantly, in cells with high Ku80 expression that were treated with a ROS scavenger, the synergism between GTS and DOX totally disappeared. These results suggest that the synergism between GTS and DOX might be based on GTS‐induced sensitization of cells to chemotherapeutics through enhanced oxidative stress, DNA damage, and apoptosis. (Cancer Sci 2008; 99: 1461–1470)