[Research progress on anti-cancer mechanisms of arsenic trioxide and artemisinin].

The formation and metastasis of tumor cells are closely related to the gene regulation. It is critical to elucidate the molecular mechanism of a compound using in cancer therapy. In this article, we reviewed the anti-cancer molecular mechanism of arsenic trioxide and artemisinin. Its anti-cancer function mainly includes: regulation of cell cycle regulatory proteins to inhibit tumor cell proliferation, cell apoptosis signal transduction pathway to promote apoptosis in tumor cells, immortalization associated genes to reduce the life of tumor cells, angiogenesis/invasion/metastasis gene to block the spread of tumor cells, promoter methylation and protein ubiquitination gene to enhance anti-oncogene expression and ubiquitin- mediated protein degradation, micro RNA to inhibit proliferation or induce apoptosis in tumor cells, DNA synthesis and repair of DNA damage and repair gene to decrease the DNA synthesis of tumor cells, signal transduction pathways of cell proliferation/apoptosis and invasion/metastasis etc., the expression of hormone receptors and so on. We indicated the problems existing in current studies and also prospected the future of using the compound to fight cancer.

Proteomic and bioinformatic analyses of possible target-related proteins of gambogic acid in human breast carcinoma MDA-MB-231 cells.

Gambogic acid (GA) is an anticancer agent in phase ‖b clinical trial in China but its mechanism of action has not been fully clarified. The present study was designed to search the possible target-related proteins of GA in cancer cells using proteomic method and establish possible network using bioinformatic analysis. Cytotoxicity and anti-migration effects of GA in MDA-MB-231 cells were checked using MTT assay, flow cytometry, wound migration assay, and chamber migration assay. Possible target-related proteins of GA at early (3 h) and late stage (24 h) of treatment were searched using a proteomic technology, two-dimensional electrophoresis (2-DE). The possible network of GA was established using bioinformatic analysis. The intracellular expression levels of vimentin, keratin 18, and calumenin were determined using Western blotting. GA inhibited cell proliferation and induced cell cycle arrest at G2/M phase and apoptosis in MDA-MB-231 cells. Additionally, GA exhibited anti-migration effects at non-toxic doses. In 2-DE analysis, totally 23 possible GA targeted proteins were found, including those with functions in cytoskeleton and transport, regulation of redox state, metabolism, ubiquitin-proteasome system, transcription and translation, protein transport and modification, and cytokine. Network analysis of these proteins suggested that cytoskeleton-related proteins might play important roles in the effects of GA. Results of Western blotting confirmed the cleavage of vimentin, increase in keratin 18, and decrease in calumenin levels in GA-treated cells. In summary, GA is a multi-target compound and its anti-cancer effects may be based on several target-related proteins such as cytoskeleton-related proteins.

Pungent ginger components modulates human cytochrome P450 enzymes in vitro.

AIM: Ginger rhizome is used worldwide as a spicy flavor agent. This study was designed to explore the potential effects of pungent ginger components, 6-, 8-, and 10-gingerol, on human cytochrome P450 (CYP450) enzymes that are responsible for the metabolism of many prescription drugs. METHODS: The activities of human CYP2C9, CYP2C19, CYP2D6, and CYP3A4 were analyzed using Vivid P450 assay kits. The mRNA expression of CYP3A4 in human hepatocellular carcinoma cell line HepG2 was measured using quantitative real-time PCR assay. RESULTS: All three gingerols potently inhibited CYP2C9 activity, exerted moderate inhibition on CYP2C19 and CYP3A4, and weak inhibion on CYP2D6. 8-Gingerol was the most potent in inhibition of P450 enzymes with IC50 values of 6.8, 12.5, 8.7, and 42.7 µmol/L for CYP2C9, CYP2C19, CYP3A4, and CYP2D6, respectively. By comparing the effects of gingerols on CYP3A4 with three different fluorescent substrate probes, it was demonstrated that the inhibition of gingerols on CYP3A4 had no substrate-dependence. In HepG2 cells, 8-gingerol and 10-gingerol inhibited, but 6-gingerol induced mRNA expression of CYP3A4. CONCLUSION: 6-, 8-, and 10-gingerol suppress human cytochrome P450 activity, while 8- and 10-gingerol inhibit CYP3A4 expression. The results may have an implication for the use of ginger or ginger products when combined with therapeutic drugs that are metabolized by cytochrome P450 enzymes.

Proteomic studies on protective effects of salvianolic acids, notoginsengnosides and combination of salvianolic acids and notoginsengnosides against cardiac ischemic-reperfusion injury.

ETHNOPHARMACOLOGICAL RELEVANCE: Salvia miltiorrhiza and Panax notoginseng are popularly used traditional Chinese medicine for cardiovascular disorders and they are often used in the form of combination. However, mechanisms of their cardioprotective effects were still not clear. In the present study, the protective effects of salvianolic acids (SA), notoginsengnosides (NG) and combination of SA and NG (CSN) against rat cardiac ischemia-reperfusion injury were checked and the protein expression profiles of heart tissues were examined to search their possible protein targets. MATERIALS AND METHODS: The cardioprotective effects of SA, NG and CSN were checked in a rat model of ischemia-reperfusion (IR) by temporarily occluding coronary artery for 20 min followed by reperfusion. Rats were grouped into sham-operation group, IR group, IR+SA group, IR+NG group and IR+CSN group. The plasma creatine kinase (CK) activities were measured using commercial kit and the percentages of infarcted area in total ventricle tissue were calculated after nitroblue-tetrazolium (N-BT) staining of heart tissue slices. Two-dimensional protein electrophoresis (2-DE) was used to check the protein expression profiles of heart tissues. Then, proteins differentially expressed between IR group and sham-operation group were identified using matrix assisted laser desorption ionization-time of flight-mass spectrometry/mass spectrometry (MALDI-TOF MS/MS). The regulative effects of SA, NG and CSN on these IR-related proteins were analyzed. RESULTS: Treatments including SA, NG and CSN all showed cardioprotective effects against ischemia-reperfusion injury and CSN exhibited to be the best. Eighteen proteins involved in IR injury were found. These proteins are involved in pathways including energy metabolism, lipid metabolism, muscle contraction, heat shock stress, cell survival and proliferation. The regulation of these proteins by SA, NG or CSN suggested possible protein targets in their cardioprotective effects. CONCLUSIONS: SA and NG showed both similarity and difference in their protein targets involved in cardioprotective effects. The capability of CSN to regulate both protein targets of SA and NG might be the basis of CSN to show cardioprotective effects better than that of SA or NG.

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.

Differential proteomic analysis of platelets suggested possible signal cascades network in platelets treated with salvianolic acid B.

BACKGROUND: Salvianolic acid B (SB) is an active component isolated from Danshen, a traditional Chinese medicine widely used for the treatment of cardiovascular disorders. Previous study suggested that SB might inhibit adhesion as well as aggregation of platelets by a mechanism involving the integrin α2ß1. But, the signal cascades in platelets after SB binding are still not clear. METHODOLOGY/PRINCIPAL FINDINGS: In the present study, a differential proteomic analysis (two-dimensional electrophoresis) was conducted to check the protein expression profiles of rat platelets with or without treatment of SB. Proteins altered in level after SB exposure were identified by MALDI-TOF MS/MS. Treatment of SB caused regulation of 20 proteins such as heat shock-related 70 kDa protein 2 (hsp70), LIM domain protein CLP-36, copine I, peroxiredoxin-2, coronin-1 B and cytoplasmic dynein intermediate chain 2C. The regulation of SB on protein levels was confirmed by Western blotting. The signal cascades network induced by SB after its binding with integrin α2ß1 was predicted. To certify the predicted network, binding affinity of SB to integrin α2ß1 was checked in vitro and ex vivo in platelets. Furthermore, the effects of SB on protein levels of hsp70, coronin-1B and intracellular levels of Ca²+ and reactive oxygen species (ROS) were checked with or without pre-treatment of platelets using antibody against integrin α2ß1. Electron microscopy study confirmed that SB affected cytoskeleton structure of platelets. CONCLUSIONS/SIGNIFICANCE: Integrin α2ß1 might be one of the direct target proteins of SB in platelets. The signal cascades network of SB after binding with integrin α2ß1 might include regulation of intracellular Ca²+ level, cytoskeleton-related proteins such as coronin-1B and cytoskeleton structure of platelets.

Cytotoxicity of 9,11-dehydroergosterol peroxide isolated from Ganoderma lucidum and its target-related proteins.

The cytotoxicty of 9,11-dehydroergosterol peroxide (DHEP) isolated from the fruiting bodies of Ganoderma lucidum on HeLa cells was studied. DHEP treatment for 48 h inhibited the proliferation of HeLa human cervical carcinoma cells with an IC50-value of 8.58 +/- 0.98 microM. Morphological changes of DHEP-treated cells indicated that DHEP induced apoptosis in HeLa cells. To identify the cellular targets of DHEP, two-dimensional electrophoresis analysis was performed to compare the protein expression profiles of DHEP-treated cells with that of control cells. Proteins altered in expressional level after DHEP exposure were identified by MALDI-TOF MS/MS. The cytotoxic effect of DHEP was associated with regulated expression of 6 proteins. Stathmin 1 might be an important target-related protein of DHEP. The regulation of stathmin 1 by DHEP treatment was also confirmed by Western blotting.

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.

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.

A new dolabrane-type diterpene from Ceriops tagal.

A new dolabrane-type diterpene named tagalsin O 1, together with six known analogues 2-7, were isolated from the aerial part of the mangrove plant Ceriops tagal. The structures and relative configurations were elucidated on the basis of their spectroscopic data. Cytotoxicity of the isolated compounds against HeLa human cervical carcinoma cancer cell line was evaluated.

Proteomic analysis of possible target-related proteins of cyclophosphamide in mice thymus.

Cyclophosphamide (Cy) could induce immuno-suppression such as thymus atrophy and inhibition of lymphocyte proliferation response in mice. But, the mechanism of its effect is still not clear. Polysaccharides isolated from spore of Ganoderma lucidum (GL-SP) could, at least partly, restore the immunological effects against Cy-induced immuno-suppression. In the present study, a two-dimensional gel electrophoresis (2-DE)-based comparative proteomic method was conducted to identify the possible target-related proteins of Cy in mice thymus including those could be influenced by GL-SP. Fifteen proteins differentially expressed in Cy-treated mice compared with control were identified. Among the fifteen proteins, combined use of GL-SP with Cy could not affect Cy-induced expression change of three proteins, totally prevented Cy-induced expression change of six proteins, partly prevented Cy-induced expression change of four proteins and further enhanced Cy-induced expression change of two proteins. Results of the present study shed light on the mechanism of Cy-induced immuno-suppression as well as the protective effect of GL-SP against toxicity of Cy.

Cytotoxic constituents of chinese propolis.

A pair of new flavanol racemates (1a and 1b) and a new flavanol racemic mixture (2) were isolated from crude propolis from Henan Province, People's Republic of China. Also obtained were nine known compounds, including two flavones, four flavonols, two flavanols, and isoferulic acid. Spectroscopic analysis was employed to assign the structures of these new compounds and the absolute configurations of 1a and 1b. Cytotoxicity of the isolated compounds against the HeLa human cervical carcinoma cancer cell line was evaluated, with only compounds 1a, 1b, 2, and rhamnetin (3) being active.

Cytotoxic polyprenylated xanthones from the resin of Garcinia hanburyi.

Twelve new xanthones (1-12), a pair of new natural products (13 and 14), and 18 known related compounds were isolated from the resin of Garcinia hanburyi. The structures of 1-14 were elucidated by detailed spectroscopic analyses. A cytotoxic assay of the isolated compounds revealed that, with the exception of 2, these compounds were active against the HeLa tumor cell line.

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 G(0)-G(1) 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.

Proteomics characterization of the cytotoxicity mechanism of ganoderic acid D and computer-automated estimation of the possible drug target network.

Triterpenes isolated from Ganoderma lucidum could inhibit the growth of numerous cancer cell lines and were thought to be the basis of the anticancer effects of G. lucidum. Ganoderic acid D (GAD) is one of the major components in Ganoderma triterpenes. GAD treatment for 48 h inhibited the proliferation of HeLa human cervical carcinoma cells with an IC(50) value of 17.3 +/- 0.3 microM. Flow cytometric analysis and DNA fragmentation analysis indicated that GAD induced G(2)/M cell cycle arrest and apoptosis. To identify the cellular targets of GAD, two-dimensional gel electrophoresis was performed, and proteins altered in expressional level after GAD exposure of cells were identified by MALDI-TOF MS/MS. The regulation of proteins was also confirmed by Western blotting. The cytotoxic effect of GAD was associated with regulated expression of 21 proteins. Furthermore these possible GAD target-related proteins were evaluated by an in silico drug target searching program, INVDOCK. The INVDOCK analysis results suggested that GAD could bind six isoforms of 14-3-3 protein family, annexin A5, and aminopeptidase B. The direct binding affinity of GAD toward 14-3-3 zeta was confirmed in vitro using surface plasmon resonance biosensor analysis. In addition, the intensive study of functional association among these 21 proteins revealed that 14 of them were closely related in the protein-protein interaction network. They had been found to either interact with each other directly or associate with each other via only one intermediate protein from previous protein-protein interaction experimental results. When the network was expanded to a further interaction outward, all 21 proteins could be included into one network. In this way, the possible network associated with GAD target-related proteins was constructed, and the possible contribution of these proteins to the cytotoxicity of GAD is discussed in this report.