Induction of G(1) cell cycle arrest and p27(KIP1) increase by panaxydol isolated from Panax ginseng

Key Targets and Molecular Mechanisms of the Fat-soluble Components of Ginseng for Lung Cancer Treatment

OBJECTIVE

To analyze the regulatory effects and key targets of the fat-soluble components of ginseng in lung cancer.

METHODS

Gas chromatography-mass spectrometry and the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform were used to analyze and identify the fat-soluble components of ginseng. Network pharmacology was used to analyze the therapeutic targets of the fat-soluble components of ginseng in lung cancer and screen key proteins. In vitro assays were conducted to verify the effects of the active fat-soluble components of ginseng on proliferation and apoptosis in lung cancer cells and to verify the regulation of key proteins.

RESULTS

Ten active fat-soluble components of ginseng were screened for follow-up. Network pharmacology showed 33 overlapping targets between the active fat-soluble components of ginseng and lung cancer, and functional enrichment of the targets showed involvement of response to nitrogen, hormone response, membrane raft, and positive regulation of external stimulus. Pathway enrichment analysis showed vascular endothelial growth factor (VEGF) signaling, adipocyte lipolysis regulation, chronic myelogenous leukemia, endocrine resistance, and NSCLC-related pathways. A protein-protein interaction network was constructed, and the top 10 targets were selected in accordance with their scores. Ultimately, five target genes (EGFR, KDR, MAPK3, PTPN11, and CTNNB1) were selected in combination with literature mining for subsequent experimental verification. Proliferation assays showed that the growth of lung cancer cells was significantly decreased in a concentration-dependent manner in the fat-soluble components of ginseng intervention group compared with controls. Flow cytometry showed that active fat-soluble components of ginseng promoted apoptosis in a concentration-dependent manner in lung cancer cells. Western blot and quantitative real-time PCR showed that levels of the five key proteins and mRNAs were significantly decreased in the intervention group; furthermore, histone protein and mRNA levels were significantly higher in the high-concentration intervention group compared with the low-concentration group.

CONCLUSION

The active fat-soluble components of ginseng inhibited the growth of lung cancer cells and promoted apoptosis. The underlying regulatory mechanisms may be related to signaling pathways involving EGFR, KDR, MAPK3, PTPN11, and CTNNB1.

d-Borneol enhances cisplatin sensitivity via p21/p27-mediated S-phase arrest and cell apoptosis in non-small cell lung cancer cells and a murine xenograft model

Background

Cisplatin (CDDP) is commonly used to treat non-small cell lung cancer (NSCLC), but the appearance of drug resistance greatly hinders its efficacy. Borneol may promote drug absorption; however, synergism between borneol and CDDP in suppressing NSCLC is not clearly understood. Hence, we investigated borneol as a novel chemosensitizer to support chemotherapeutic efficacy and reduce side effects.

Methods

We compared viability after exposure to d-borneol, l-borneol, and synthetic borneol in two NSCLC cell lines, A549 and H460, and selected the most sensitive cells. We then assessed synergy between borneol forms and CDDP in cisplatin-resistant NSCLC cells, H460/CDDP. Next, we identified effective concentrations and exposure times. Subsequently, we evaluated cell migration via wound healing and cell proliferation via clone formation assay. Then, we focused on P-glycoprotein (P-gp) function, cell cycle, apoptosis, and RNA sequencing to elucidate underlying molecular mechanisms for synergy. Finally, we used an H460/CDDP xenograft tumor model to verify antitumor activity and safety in vivo. Data were examined using one-way analysis of variance (ANOVA) for multiple datasets or t-test for comparisons between two variables.

Results

d-Borneol was more effective in H460 than A549 cells. d-Borneol combined with CDDP showed greater inhibition of cell proliferation, migration, and clone formation in H460/CDDP cells than CDDP alone. RNA sequencing (RNA-seq) analysis identified differentially expressed genes enriched in cell cycle pathways. The impact of d-borneol on CDDP chemosensitivity involved arrest of the cell cycle at S phase via p27/p21-mediated cyclinA2/D3-CDK2/6 signaling and activation of intrinsic apoptosis via p21-mediated Bax/Bcl-2/caspase3 signaling. Further, d-borneol ameliorated drug resistance by suppressing levels and activity of P-gp. Cotreatment with d-borneol and CDDP inhibited tumor growth in vivo and reduced CDDP-caused liver and kidney toxicity.

Conclusions

d-Borneol increased the efficacy of cisplatin and reduced its toxicity. This compound has the potential to become a useful chemosensitizer for drug-resistance NSCLC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s11658-022-00362-4.

DTYMK promote hepatocellular carcinoma proliferation by regulating cell cycle

Overexpression of DTYMK is related with tumorigenesis and progression in several human tumors. However, the role of upregulated DTYMK in hepatocellular carcinoma (HCC) patients still remains unclear. In this study, the DTYMK expression in HCC tumors was evaluated in three GEO series (GSE14520, GSE54236, GSE63898), TCGA-LIHC, and ICGC-IRLR-JP cohorts. Survival analysis of DTYMK based on TCGA-LIHC and ICGC-LIRI-JP cohorts was conducted. We found that DTYMK was dramatically upregulated in tumor tissue compared with that in adjacent liver tissue. Kaplan-Meier analysis revealed that high expression of DTYMK in HCC patients' tumor tissue was significantly corresponded to worse overall survival (OS) (P < 0.05). Further analysis showed that overexpressing DTYMK led to poor relapse free survival (RFS) and disease-specific survival (DSS) (all P < 0.05). In conclusion, DTYMK is upregulated in tumors and correlated with poor prognosis in HCC patients. In our report, DTYMK is higher expression in HCC cancer tissue and cell line than tumor adjacent tissue and normal liver cell line. Knocking down DTYMK can inhabit tumor cell proliferation by interfering cell cycle, whereas overexpression of DTYMK can promote tumor cell proliferation. These findings indicate that upregulation of DTYMK enhances tumor growth and proliferation by promoting cell cycle.

Design, Synthesis, Characterization, and Crystal Structure Studies of Nrf2 Modulators for Inhibiting Cancer Cell Growth In Vitro and In Vivo

Nrf2 is one of the important therapeutic targets studied extensively in several cancers including the carcinomas of the colon and rectum. However, to date, not many Nrf2 inhibitors showed promising results for retarding the growth of colorectal cancers (CRCs). Therefore, in this study, first, we have demonstrated the therapeutic effect of siRNA-mediated downmodulation of Nrf2 on the proliferation rate of CRC cell lines. Next, we have designed, synthesized, characterized, and determined the crystal structures for a series of tetrahydrocarbazoles (THCs) and assessed their potential to modulate the activity of Nrf2 target gene NAD(P)H:quinone oxidoreductase (NQO1) activity by treating colorectal carcinoma cell line HCT-116. Later, the cytotoxic potential of compounds was assessed against cell lines expressing varying amounts of Nrf2, viz., breast cancer cell lines MDA-MB-231 and T47D (low functionally active Nrf2), HCT-116 (moderately active Nrf2), and lung cancer cell line A549 (highly active Nrf2), and the lead compound 5b was tested for its effect on cell cycle progression in vitro and for retarding the growth of Ehrlich ascites carcinomas (EACs) in mice. Data from our study demonstrated that among various compounds 5b exhibited better therapeutic index and retarded the growth of EAC cells in mice. Therefore, compound 5b is recommended for further development to target cancers.

Fraxetin inhibits the growth of colon adenocarcinoma cells via the Janus kinase 2/signal transducer and activator of transcription 3 signalling pathway

OBJECTIVE

Fraxetin, extracted from the bark of Fraxinus rhynchophylla, has been shown to exhibit antitumour and anti-inflammatory pharmacological properties. However, the mechanism underlying its anticancer activity towards colon adenocarcinoma (COAD) is not well understood. We aimed to determine the antitumour effect of fraxetin on COAD cell lines and elucidate its biochemical and molecular targets.

METHODS

The cell lines HCT116 and DLD-1 were used to evaluate the in vitro antitumour efficacy of fraxetin. Cytotoxicity and viability were assessed by CCK-8 and plate colony formation assays. Flow cytometry was used to assess apoptosis and cell cycle progression in fraxetin-treated COAD cells. Western blot, RT-qPCR, molecular docking, immunohistochemical, and immunofluorescence analyses were used to gain insights into cellular and molecular mechanisms. Preclinical curative effects were evaluated in nude mouse xenograft models.

RESULTS

Fraxetin significantly inhibited COAD cell proliferation in both dose- and time-dependent manners, specifically by inducing S-phase cell cycle arrest and triggering intrinsic apoptosis. Additionally, the level of p-JAK2 was decreased by fraxetin via the Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) signalling pathway. Interestingly, in COAD cells, fraxetin directly targeted the Y¹⁰⁰⁷ and Y¹⁰⁰⁸ residues of JAK2 to suppress its auto- or transphosphorylation, leading to decreased activation of its downstream effector STAT3 and blocking its nuclear translocation. Finally, fraxetin exhibited good tumour growth suppression activity and low toxicity.

CONCLUSIONS

Fraxetin inhibits the proliferation of COAD cells by regulating the JAK2/STAT3 signalling pathway, providing evidence that targeting JAK2 with fraxetin may offer a novel potential auxiliary therapy for COAD treatment.

Bioactive C17 and C18 Acetylenic Oxylipins from Terrestrial Plants as Potential Lead Compounds for Anticancer Drug Development

Bioactive C₁₇ and C₁₈ acetylenic oxylipins have shown to contribute to the cytotoxic, anti-inflammatory, and potential anticancer properties of terrestrial plants. These acetylenic oxylipins are widely distributed in plants belonging to the families Apiaceae, Araliaceae, and Asteraceae, and have shown to induce cell cycle arrest and/or apoptosis of cancer cells in vitro and to exert a chemopreventive effect on cancer development in vivo. The triple bond functionality of these oxylipins transform them into highly alkylating compounds being reactive to proteins and other biomolecules. This enables them to induce the formation of anti-inflammatory and cytoprotective phase 2 enzymes via activation of the Keap1–Nrf2 signaling pathway, inhibition of proinflammatory peptides and proteins, and/or induction of endoplasmic reticulum stress, which, to some extent, may explain their chemopreventive effects. In addition, these acetylenic oxylipins have shown to act as ligands for the nuclear receptor PPARγ, which play a central role in growth, differentiation, and apoptosis of cancer cells. Bioactive C₁₇ and C₁₈ acetylenic oxylipins appear, therefore, to constitute a group of promising lead compounds for the development of anticancer drugs. In this review, the cytotoxic, anti-inflammatory and anticancer effects of C₁₇ and C₁₈ acetylenic oxylipins from terrestrial plants are presented and their possible mechanisms of action and structural requirements for optimal cytotoxicity are discussed.

Ginseng aqueous extract ameliorates lambda-cyhalothrin-acetamiprid insecticide mixture for hepatorenal toxicity in rats: Role of oxidative stress-mediated proinflammatory and proapoptotic protein expressions

This study was carried out to evaluate the protective effects of Panax ginseng aqueous extract (GAE) against hepatorenal toxicity induced by lambda-cyhalothrin-acetamiprid insecticide mixture in rats. A total of 32 male albino rats were assigned into four groups. Normal control group received distilled water. Insecticide control group intoxicated with the insecticide at a dose of 2.14 mg/kg b.wt orally day after day for 45 days. GAE control group was treated with GAE at a dose 200 mg/kg b.wt orally. GAE experimental group was administered GAE 1 hour before insecticide administration. Intoxication of rats with the insecticide caused a significant increase in serum aspartate aminotransferase and alanine aminotransferase activities and urea and creatinine levels as well as malondialdehyde concentration and proteins expression of caspase-3 and induced nitric oxide synthase in hepatic and renal tissues. However, it decreased the serum levels of total protein and globulin and reduced the glutathione content and catalase activity in hepatic and renal tissues. In addition, insecticide induced histopathological alterations in both hepatic and renal tissues. In contrast, GAE modulated insecticide-induced alterations in liver and kidney functions and structures as it ameliorated the effects of insecticide on the above mentioned parameters. These results indicated that GAE was a potent antioxidant agent that could protect rats against insecticide-induced hepatorenal toxicity.

Panaxydol Derived from Panax ginseng Inhibits G1 Cell Cycle Progression in Non-small Cell Lung Cancer via Upregulation of Intracellular Ca2+ Levels

Panaxydol, a polyacetylenic compound derived from Panax ginseng has been reported to suppress the growth of cancer cells. However, the molecular mechanisms underlying cell cycle arrest by this compound in non-small cell lung cancer (NSCLC) are unknown. Our study found that panaxydol treatment induced cell cycle arrest at G₁ phase in NSCLC cells. The cell cycle arrest was accompanied by down-regulation of the protein expression of cyclin-dependent kinase (CDK) 2, CDK4, CDK6, cyclin D₁ and cyclin E, and decrease in the phosphorylation of retinoblastoma (Rb) protein. Furthermore, up-regulation of cyclin-dependent kinase inhibitor (CDKI) p21^CIP1/WAF1 and p27^KIP1 was observed in panaxydol-treated NSCLC cells. In addition, panaxydol also induced accumulation of intracellular Ca²⁺ ([Ca²⁺]_i). (Acetyloxy)methyl 2-({2-[(acetyloxy)methoxy]-2-oxoethyl}[2-(2-{2-[bis({2-[(acetyloxy)methoxy]-2-oxoethyl})amino]phenoxy}ethoxy)phenyl]amino)acetate (BAPTA-AM), the Ca²⁺ chelator, attenuated not only panaxydol-induced accumulation of [Ca²⁺]_i, but also G₁ cell cycle arrest and decrease of CDK6 and cyclin D₁ protein expression level. These results demonstrated that the anti-proliferative effects of panaxydol were caused by cell cycle arrest, which is closely linked to the up-regulation of [Ca²⁺]_i and represents a promising approach for the treatment of lung cancer.

Fresh red raspberry phytochemicals suppress the growth of hepatocellular carcinoma cells by PTEN/AKT pathway

The red raspberry (Rubus idaeus L.) is a common fruit worldwide and its extract has been found to inhibit the growth of many types of tumors, mainly because it is rich in bioactive phytochemicals. However, the mechanism underlying its anticancer activity in hepatocellular carcinoma (HCC) is not well understood. Herein, the aim of this study was to determine the effects of red raspberry phytochemicals on the proliferation of hepatocellular carcinoma cells and to elucidate its biochemical and molecular targets. CCK8 and colony formation, as well as flow cytometry assays, were employed to determine the effects of red raspberry extract (RRE) on cell proliferation and cell cycle distribution in HCC cells. Our results showed that RRE significantly inhibited cell proliferation and arrested cell cycle progression at the S phase in HCC cells. RRE increased the expression of phosphatase and tensin homologue deleted on chromosome 10 (PTEN) by reducing the methylation status of the PTEN gene promoter and inhibiting DNMT1 expression and regulated AKT signaling pathway. These findings show that red raspberry phytochemicals inhibit the proliferation of HCC cells by regulating PTEN/AKT signaling pathway, providing evidence that RRE may be used as a potential auxiliary therapy for patients with HCC.

Protocatechualdehyde Induces S-Phase Arrest and Apoptosis by Stimulating the p27(KIP1)-Cyclin A/D1-CDK2 and Mitochondrial Apoptotic Pathways in HT-29 Cells

Protocatechualdehyde (PCA) extracted from Phellinus gilvus exhibits anti-cancer activity in human colorectal carcinoma cells (HT-29). However, the underlying mechanisms remain poorly understood. We performed an in vitro study involving MTT, flow cytometry, RT-PCR, and western blot analyses to investigate the effects of PCA treatment on cell proliferation, cell cycle distribution, apoptosis, and expression of several cell cycle-related genes in HT-29 cells. The treatment enhanced S-phase cell cycle and apoptosis in HT-29 cells in a dose-dependent manner. Western blot results showed that PCA treatment decreased the expression levels of cyclin A, cyclin D1, and p27^KIP1 but increased those of cyclin-dependent kinase 2 (CDK2) in HT-29 cells. Furthermore, the expression levels of B-cell lymphoma/leukemia-2 (Bcl-2) and B-cell lymphoma/leukemia-xL (Bcl-xL) were down-regulated, whereas the levels of BH3-interacting domain death agonist (Bid), Bcl-2 homologous antagonist/killer (Bak), and cytosolic cytochrome c were significantly upregulated. Thus, the enzymes caspases-9, -3, -8, and -6 were found to be activated in HT-29 cells with PCA treatment. These results indicate that PCA-induced S-phase cell cycle arrest and apoptosis involve p27^KIP1-mediated activation of the cyclin-A/D1-Cdk2 signaling pathway and the mitochondrial apoptotic pathway.

Anti-proliferation Effect on Human Breast Cancer Cells via Inhibition of pRb Phosphorylation by Taiwanin E Isolated from Eleutherococcus trifoliatus

Eleutherococcus trifoliatus has been used as a folk medicine since ancient times, especially as refreshing qi medicines. In our current study, taiwanin E, which possesses strong cytotoxicity, was isolated from the branches of E. trifoliatus by using a bioactivity guided fractionation procedure. Taiwanin E presented a potent anti-proliferation activity on the growth of a human breast adenocarcinoma cell line (MCF-7), with an IC50 value for cytotoxicity of 1.47 μM. Cell cycle analysis revealed that the proportion of cells in the G0/G1 phase increased in a dose-dependent manner (from 79.4% to 90.2%) after 48 h exposure to taiwanin E at a dosage range from 0.5 to 4μM. After treatment with taiwanin E, phosphorylation of retinoblastoma protein (pRb) in MCF-7 cells was inhibited, accompanied by a decrease in the levels of cyclin D1, cyclin D3 and cyclin-dependent kinase 4 (cdk4) and cdk6; in addition, there was an increase in the expression of cyclin-dependent kinase inhibitors p21WAF-1/Cip1 and p27Kip1. The results suggest that taiwanin E inhibits cell cycle progression of MCF-7 at the G0/G1 transition.

Oridonin induces apoptosis and cell cycle arrest of gallbladder cancer cells via the mitochondrial pathway

Background

Gallbladder cancer is the most frequent malignancy of the bile duct with high aggressive and extremely poor prognosis. The main objective of the paper was to investigate the inhibitory effects of oridonin, a diterpenoid isolated from Rabdosia rubescens, on gallbladder cancer both in vitro and in vivo and to explore the mechanisms underlying oridonin-induced apoptosis and cell cycle arrest.

Methods

The anti-tumor activity of oridonin on SGC996 and NOZ cells was assessed by the MTT and colony forming assays. Cell cycle changes were detected by flow cytometric analysis. Apoptosis was detected by annexin V/PI double-staining and Hoechst 33342 staining assays. Loss of mitochondrial membrane potential was observed by Rhodamine 123 staining. The in vivo efficacy of oridonin was evaluated using a NOZ xenograft model in athymic nude mice. The expression of cell cycle- and apoptosis-related proteins in vitro and in vivo was analyzed by western blot analysis. Activation of caspases (caspase-3, -8 and -9) was measured by caspases activity assay.

Results

Oridonin induced potent growth inhibition, S-phase arrest, apoptosis, and colony-forming inhibition in SGC996 and NOZ cells in a dose-dependent manner. Intraperitoneal injection of oridonin (5, 10, or 15 mg/kg) for 3 weeks significantly inhibited the growth of NOZ xenografts in athymic nude mice. We demonstrated that oridonin regulated cell cycle-related proteins in response to S-phase arrest by western blot analysis. In contrast, we observed inhibition of NF-κB nuclear translocation and an increase Bax/Bcl-2 ratio accompanied by activated caspase-3, caspase-9 and PARP-1 cleavage after treatment with oridonin, which indicate that the mitochondrial pathway is involved in oridonin-mediated apoptosis.

Conclusions

Oridonin possesses potent anti-gallbladder cancer activities that correlate with regulation of the mitochondrial pathway, which is critical for apoptosis and S-phase arrest. Therefore, oridonin has potential as a novel anti-tumor therapy for the treatment of gallbladder cancer.

Secretome profiling reveals the signaling molecules of apoptotic HCT116 cells induced by the dietary polyacetylene gymnasterkoreayne B

Dietary polyacetylenes from various foods have been receiving attention as promising cancer chemopreventive agents. However, until now, the detailed molecular mechanism and the regulatory proteins underlying these effects have not been elucidated. We investigated the effects of gymnasterkoreayne B (GKB), a model dietary polyacetylene from wild vegetables, on the programmed cell death of HCT116 human colorectal cancer cells. GKB inhibited HCT116 cell proliferation by inducing apoptotic cell death. GKB treatment resulted in ROS accumulation, leading to the activation of both intrinsic and extrinsic apoptotic pathway. We also found that FN1, TGFB1, APP, SERPINE1, HSPD1, SOD1, TXN, and ACTN4 may act as secretory signaling molecules during GKB-induced apoptotic cell death using LC-MS/MS identification followed by spectrum counting, statistical calculation, and gene ontology analysis. The secretory proteins suggested in this study may be promising candidates involved in apoptotic cell death of cancer cells induced by GKB that warrant further functional study.

Activation of P27kip1-cyclin D1/E-CDK2 pathway by polysaccharide from Phellinus linteus leads to S-phase arrest in HT-29 cells

Our previous study showed that polysaccharide (P1) from Phellinus linteus exhibits a significant inhibitive activity on human colorectal carcinoma cells (HT-29). However its novel molecular mechanism remains unknown. To obtain insights into P1's mechanism of action, we examined its effects on cell proliferation in vitro and in vivo, cell cycle distribution, apoptosis, autophagy, and expression of several cell cycle interrelated proteins in HT-29 cells. Interestingly, we found that volume and weight of the solid tumor significantly decreased in P1 (200mg/kg)-treated mice compared with the control. However, slightly increased the body weight of the P1 treated tumor-bearing mice, with no significant increased ALT, AST levels in serum and LPO concentration in liver and kidney indicated that P1 has no toxicity to mammals at a dose of 200mg/kg. Furthermore, P1 caused a significantly dose-dependent increase in the S-phase cell cycle, but no apoptosis and autophagy in HT-29 cells. RT-PCR and Western blot results showed significantly down-regulated expressions of cyclin D1, cyclin E, and CDK2, as well as increased expressions of P27kip1 in P1 (100 μg/mL)-treated HT-29 cells. These results suggested that the activation of P27kip1-cyclin D1/E-CDK2 pathway is involved in P1-induced S-phase cell cycle arrest in HT-29 cells.

Growth inhibition and induction of differentiation by panaxydol in rat C6 glioma cells

OBJECTIVES

Panaxydol is a naturally occurring non-peptidyl small molecule isolated from the lipophilic fractions of Panax notoginseng, a well-known Chinese traditional medicine. In this study, we aimed to investigate the effects of panaxydol on growth inhibition and its mechanisms in C6 rat glioma cells.

METHODS

The effects of panaxydol on cell proliferation, morphologic changes, glial fibrillary acidic protein (GFAP) expression and cell cycle regulation in rat C6 cells were evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay, hematoxylin and eosin (HE) staining, immunocytochemistry, flow cytometric analysis and Western blot respectively.

RESULTS

Panaxydol markedly inhibited the proliferation of C6 cells in a dose-dependent manner with IC50 of 39.5 +/- 2.3 microM. In addition, the cell morphologic changes and increased expression of GFAP in C6 cells in the presence of panaxydol implied a cellular differentiation. Flow cytometric analysis revealed that panaxydol-treated cells accumulated in G0/G1 phase with a marked decrease in the number of C6 cells at S phase. Western blot analysis demonstrated that panaxydol resulted in an increase in the protein expression of p27 in C6 cells as early as 3 hours after treatment consistent with the differentiation response, but protein expression of p53, p21, p16 and pRb remained unchanged.

CONCLUSION

These findings suggest that panaxydol inhibits the proliferation of C6 cells via G0/G1 cell cycle arrest in association with induction of p27 expression and differentiation.

A limited role of p53 on the ability of a Hexane fraction of American ginseng to suppress mouse colitis

Ulcerative colitis (UC) is debilitating and carries a high colon cancer risk. Apoptosis of inflammatory cells is a key mechanism regulating UC. We have recently shown that American ginseng (AG), and to a greater extent, a Hexane fraction of AG (HAG) can cause apoptosis and suppress mouse colitis through a p53-mediated mechanism. Here, we tested the hypothesis that HAG suppresses colitis through a p53 mechanism. We found only a limited impact of p53 in the ability of HAG to induce inflammatory cell apoptosis and suppress mouse colitis in vitro and in vivo. Finally, we asked whether HAG could cause cell cycle arrest of HCT116 colon cancer cells in vitro. Interestingly, HAG caused a G1 arrest of such cells independent of p53 status. Findings are significant because HAG suppresses colitis and associated colon cancer, and mutation in p53 is observed in most colitis-driven colon cancers. Therefore, HAG might be very effective in targeting the inflammatory cells and cancer cells since it induces apoptosis of inflammatory cells and cell cycle arrest in both p53^−/− and WT p53 colon cancer cells.

Antitrypanosomal properties of Panax ginseng C. A. Meyer: new possibilities for a remarkable traditional drug

African trypanosomiasis is still a major health problem in many sub-Saharan countries in Africa. We investigated the effects of three preparations of Panax ginseng, Panax notoginseng, isolated ginsenosides, and the polyacetylene panaxynol on Trypanosoma brucei brucei and the human cancer cell line HeLa. Hexane extracts and the pure panaxynol were toxic and at the same time highly selective against T. b. brucei, whereas methanol extracts and 12 isolated ginsenosides were significantly less toxic and showed only weak selectivity. Panaxynol was cytotoxic against T. b. brucei at the concentration of 0.01 µg/mL with a selectivity index of 858, superior even to established antitrypanosomal drugs. We suggest that the inhibition of trypanothione reductase, which is only found in trypanosomes, might explain the observed selectivity. The high selectivity together with a cytotoxic concentration in the range of the bioavailability makes panaxynol and other polyacetylenes in general very promising lead compounds for the treatment of African trypanosomiasis.

Induction of differentiation by panaxydol in human hepatocarcinoma SMMC-7721 cells via cAMP and MAP kinase dependent mechanism

Panaxydol (PND) is one of the main non-peptidyl small molecules isolated from the lipophilic fractions of Panax notoginseng. The present study was carried out to demonstrate the potential effects of panaxydol on the induction of differentiation of human liver carcinoma cell lines SMMC-7721. Cell viability was evaluated by MTT method and Trypan blue exclusion assay respectively. The changes of morphology were detected by transmission electron microscope. Inhibitors were applied to detect the signaling pathway of differentiation. The level of intracellular cyclic AMP was determined by radioimmunoassay. The expression of p-ERK, Id1, and p21 were determined by Western blot. We found that panaxydol inhibit the proliferation of SMMC-7721 cells and caused the morphology and ultrastructure changes of SMMC-7721. Moreover, panaxydol dose-dependently increased the secretion of albumin and alkaline phosphatase activity, and decreased the secretion of AFP correspondingly. These changes of differentiation markers in SMMC-7721 can be reversed by the protein kinase A inhibitor RpcAMPS and by MAP kinase kinase 1/2 inhibitor U0126 or sorafenib. Intracellular cAMP was elevated by panaxydol in SMMC-7721 cells. Panaxydol dose-dependently decreased the expression of regulatory factors Id1 and increased the protein levels of p21 and p-ERK1/2 correspondingly. It suggested panaxydol might be of value for further exploration as a potential anti-cancer agent via cAMP and MAP kinase-dependent mechanism.

Panaxydol induces apoptosis through an increased intracellular calcium level, activation of JNK and p38 MAPK and NADPH oxidase-dependent generation of reactive oxygen species

Panaxydol, a polyacetylenic compound derived from Panax ginseng roots, has been shown to inhibit the growth of cancer cells. In this study, we demonstrated that panaxydol induced apoptosis preferentially in transformed cells with a minimal effect on non-transformed cells. Furthermore, panaxydol was shown to induce apoptosis through an increase in intracellular Ca(2+) concentration ([Ca(2+)](i)), activation of JNK and p38 MAPK, and generation of reactive oxygen species (ROS) initially by NADPH oxidase and then by mitochondria. Panaxydol-induced apoptosis was caspase-dependent and occurred through a mitochondrial pathway. ROS generation by NADPH oxidase was critical for panaxydol-induced apoptosis. Mitochondrial ROS production was also required, however, it appeared to be secondary to the ROS generation by NADPH oxidase. Activation of NADPH oxidase was demonstrated by the membrane translocation of regulatory p47(phox) and p67(phox) subunits and shown to be necessary for ROS generation by panaxydol treatment. Panaxydol triggered a rapid and sustained increase of [Ca(2+)](i), which resulted in activation of JNK and p38 MAPK. JNK and p38 MAPK play a key role in activation of NADPH oxidase, since inhibition of their expression or activity abrogated membrane translocation of p47(phox) and p67(phox) subunits and ROS generation. In summary, these data indicate that panaxydol induces apoptosis preferentially in cancer cells, and the signaling mechanisms involve a [Ca(2+)](i) increase, JNK and p38 MAPK activation, and ROS generation through NADPH oxidase and mitochondria.

Induction of cell cycle arrest at G1 and S phases and cAMP-dependent differentiation in C6 glioma by low concentration of cycloheximide

Background

Differentiation therapy has been shown effective in treatment of several types of cancer cells and may prove to be effective in treatment of glioblastoma multiforme, the most common and most aggressive primary brain tumor. Although extensively used as a reagent to inhibit protein synthesis in mammalian cells, whether cycloheximide treatment leads to glioma cell differentiation has not been reported.

Methods

C6 glioma cell was treated with or without cycloheximide at low concentrations (0.5-1 μg/ml) for 1, 2 and 3 days. Cell proliferation rate was assessed by direct cell counting and colony formation assays. Apoptosis was assessed by Hoechst 33258 staining and FACS analysis. Changes in several cell cycle regulators such as Cyclins D1 and E, PCNA and Ki67, and several apoptosis-related regulators such as p53, p-JNK, p-AKT, and PARP were determined by Western blot analysis. C6 glioma differentiation was determined by morphological characterization, immunostaining and Western blot analysis on upregulation of GFAP and o p-STAT3 expression, and upregulation of intracellular cAMP.

Results

Treatment of C6 cell with low concentration of cycloheximide inhibited cell proliferation and depleted cells at both G2 and M phases, suggesting blockade at G1 and S phases. While no cell death was observed, cells underwent profound morphological transformation that indicated cell differentiation. Western blotting and immunostaining analyses further indicated that changes in expression of several cell cycle regulators and the differentiation marker GFAP were accompanied with cycloheximide-induced cell cycle arrest and cell differentiation. Increase in intracellular cAMP, a known promoter for C6 cell differentiation, was found to be elevated and required for cycloheximide-promoted C6 cell differentiation.

Conclusion

Our results suggest that partial inhibition of protein synthesis in C6 glioma by low concentration of cycloheximide induces cell cycle arrest at G1 and M phases and cAMP-dependent cell differentiation.

Hydrophobic constituents and their potential anticancer activities from Devil's Club (Oplopanax horridus Miq.)

ETHNOPHARMACOLOGICAL RELEVANCE

Devil's Club (Oplopanax horridus) is one of the most important spiritual and medicinal plants to many indigenous peoples of Alaska and the Pacific Northwest. It is widely used for external and internal infections as well as arthritis, respiratory ailments, digestive tract ailments, broken bones, fever, headaches, and cancer.

AIM OF THE STUDY

To investigate hydrophobic constituents and their potential anticancer activity from Devil's Club, Oplopanax horridus.

MATERIALS AND METHODS

The root bark extract of Oplopanax horridus was isolated by chromatographic techniques. Structures of isolated compounds were identified by spectroscopic methods and comparison with published data. The anti-proliferation of isolated hydrophobic constituents in human breast cancer MCF-7 cells, human colon cancer SW-480 and HCT-116 cells were tested. The potential mechanism of anti-proliferation was also investigated using cell cycle and apoptosis assays.

RESULTS AND DISCUSSION

Six compounds were isolated and structurally identified as 9,17-octadecadiene-12,14-diyne-1,11,16-triol, 1-acetate (1), oplopandiol acetate (2), falcarindiol (3), oplopandiol (4), trans-nerolidol (5) and t-cadinol (6). These compounds showed potential anticancer activities on human breast cancer and colon cancer cells, of which compound 3 possesses the strongest activity. Further cell cycle and apoptosis tests by flow cytometry showed the polyacetylenes 1-4 induced HCT-116 cell arresting in G2/M phase and inhibited proliferation by the induction of apoptosis at both earlier and later stages.

CONCLUSION

These results provide promising baseline information for the potential use of Oplopanax horridus, as well as some of the isolated compounds in the treatment of cancer.

NMR-based metabolomics approach for the differentiation of ginseng (Panax ginseng) roots from different origins

Agro-herbal materials vary in prices and qualities depending on the origin and age and the differentiation is both scientific and public health issue. Here, we describe a metabolomics approach used to discriminate ginseng roots from different sources. Six different types of ginseng roots from China and Korea were analyzed by NMR-based metabolomics. Chinese Dangsam showed prominent differences and was easily differentiated. The difference was mainly due to the large signals in the sugar region. We further analyzed the metabolomics results in subgroups. Jeonra (Korean), Choongcheong (Korean), and Chinese ginseng in subgroup 1 could be easily differentiated by the first two principal components. The loading plot for PC1 showed that the Jeonra and Chinese ginseng roots were mainly separated by sugar signals and methyl signals but that they were reverse-correlated. A diffusion-ordered spectroscopy (DOSY) analysis showed that the methyl signals are from high molecular weight compounds and that the sugar signals are either from oligosaccharides or ginsenosides. In subgroup 2, composed of Korean Choongcheong ginseng at different ages, we were able to see age-dependent transitions in the score plot. We believe our approach can be applied to detecting the adulteration of ginseng root powders and other herbal products from different origins.

Pesticide multiresidue analysis in Panax ginseng (C. A. Meyer) by solid-phase extraction and gas chromatography with electron capture and nitrogen-phosphorus detection

An analytical multi-residue method using gas chromatography coupled with electron capture and a nitrogen-phosphorus detector was investigated for the simultaneous determination of 18 commonly used insecticides and fungicides in Korean ginseng (Panax ginseng C. A. Meyer). Samples were previously extracted with an acetonitrile and cleaned up by solid-phase extraction (SPE). The calibration curves were linear, with determination coefficients higher than 0.989. Recoveries at concentrations between 0.01 and 14.9 ppm ranged from 72.3 to 117.2%, with precision, which was expressed as relative standard deviation (RSD), at values lower than 5%. The proposed method was applied to the determination of pesticide levels from 12 ginseng samples, taken from four different agricultural areas of Jeonnam province, where several insecticides and fungicides were applied. Except in one sample, tolclofos-m was the only pesticide contained at a level lower than the maximum residue limits (MRL) authorized by the Korea Food and Drug Administration (KFDA) in real ginseng samples grown for 4, 5 and 6 years.

Effects of ginseng on the proliferation of human lung fibroblasts

In this study, we investigated the effects of methanolic extracts of white ginseng (Panax ginseng C.A. MEYER) and two kinds of heat-treated ginseng made by steaming fresh ginseng at 100 degrees C for 3 hours (HTG-100) or 120 degrees C for 3 hours (HTG-120) on the cell growth of human fibroblasts. All of the tested ginseng extracts stimulated cell growth, although the effect of HTG-120 was weaker than that of the other extracts. However, none of the ginseng extracts exhibited any effect on the growth of old cells with a population doubling level (PDL) of 48.7. Flow cytometric analysis showed that ginseng extracts raised the population of cells in G0/G1 phase after treatment for 24 hours, but did not exert any effect after treatment for 48 hours. These results suggest that ginsengs exert their cell growth-promoting action mainly on younger cells at an early stage of the cell cycle, and that this effect is closely associated with an increase in the population of cells in the G0/G1 phase.

Simplified extraction of ginsenosides from American ginseng (Panax quinquefolius L.) for high-performance liquid chromatography-ultraviolet analysis

Four methods were tested for extraction and recovery of six major ginsenosides (Rb1, Rb2, Rc, Rd, Re, and Rg1) found in roots of American ginseng (Panax quinquefolius): method A, sonication in 100% methanol (MeOH) at room temperature (rt); method B, sonication in 70% aqueous MeOH at rt; method C, water extraction (90 degrees C) with gentle agitation; and method D, refluxing (60 degrees C) in 100% MeOH. After 0.5-1 h, the samples were filtered and analyzed by high-performance liquid chromatography (HPLC)-UV. A second extraction by methods C and D was done, but 85-90% of ginsenosides were obtained during the first extraction. Lyophilization of extracts did not influence ginsenoside recovery. Method D resulted in the highest significant recoveries of all ginsenosides, except Rg1. Method C was the next most effective method, while method A resulted in the lowest ginsenoside recoveries. Method B led to similar recoveries as method C. All methods used one filtration step, omitted time-consuming cleanup, but maintained clear peak resolution by HPLC, and can be used for quantitative screening of ginsenosides from roots and commercial ginseng preparations.

G1 phase arrest of the cell cycle by a ginseng metabolite, compound K, in U937 human monocytic leukamia cells

We recently reported that the ginseng saponin metabolite, compound K (20-O-beta-D-glucopyranosyl-20(S)-protopanaxadiol, IH901), inhibits the growth of U937 cells through caspase-dependent apoptosis pathway. In this study, we further characterized the effects of compound K on U937 cells and found that, in addition to apoptosis, compound K induced the arrest of the G1 phase. The compound K treated U937 cells showed increased p21 expression; an inhibitory protein of cyclin-cdk complex. The up-regulation of p21 was followed by the inactivation of cyclin D and the cdk4 protein, which act at the early G1 phase, and cyclin E, which acts at the late G1 phase. Furthermore, compound K induced the activation of JNK and the transcription factor AP-1, which is a downstream target of JNK. These findings suggest that the up-regulation of p21 and activation of JNK in the compound K treated cells contribute to the arrest of the G1 phase.

Panax ginseng: a role in cancer therapy?

Panax ginseng is a plant that has been used in traditional medicine in China for thousands of years. It is used as a general tonic or adaptogen with chronically ill patients and is frequently featured in traditional medicine prescriptions from China, Japan, and Korea used by cancer patients. The putative active compounds are the ginsenosides, of which there are more than two dozen. These compounds are found in both Panax ginseng and in other Panax species that are used in herbal medicine. Analysis of ginsenosides is being used in developing quality control assessments for ginseng, which has frequently been adulterated due to its high cost; many currently available standardized extracts do appear to contain the amounts of ginsenosides listed on package labeling. The toxicity of ginseng appears to be low: some of the reports of toxic episodes of ginseng may actually pertain to other components of multicomponent preparations. Very low incidence of toxicity has been observed in ginseng clinical trials using well-characterized preparations. Numerous pharmacological activities of ginseng and the ginsenosides have been explored: the authors review here the activities relating to cancer. Immune system modulation, antistress activities, and antihyperglycemic activities are among the most notable features of ginseng noted in laboratory and clinical analyses. Much testing has been done in humans to explore ginseng's purported antifatigue properties, but this area remains controversial. A number of investigations point to antitumor properties and other pharmacological activities related to cancer, but no trials have yet confirmed a clinically significant anticancer activity. Cancer patients may empirically find ginseng to be useful when they are fatigued, although clinical trials should be conducted to confirm its benefits.