Homoharringtonine inhibits melanoma cells proliferation in vitro and vivo by inducing DNA damage, apoptosis, and G2/M cell cycle arrest.

Homoharringtonine (HHT), an approved anti-leukemic alkaloid, has been reported effectively in many types of tumor cells. However, its effect on melanoma cells has not been investigated. And the anti-melanoma mechanism of HHT is still unknown. In this study, we detected the effects of HHT on two melanoma cell lines (A375 and B16F10) and on the A375 xenograft mouse model. HHT significantly inhibited the proliferation of melanoma cells as investigated by the CCK8 method, cell cloning assay, and EdU experiment. HHT induced A375 and B16F10 cells DNA damage, apoptosis, and G2/M cell cycle arrest as proved by TdT-mediated dUTP Nick-End Labeling (TUNEL) and flow cytometry assay. Additionally, the loss of mitochondrial membrane potential in HHT-treated cells were visualized by JC-1 fluorescent staining. For the molecule mechanism study, western blotting results indicated the protein expression levels of ATM, P53, p-P53, p-CHK2, γ-H2AX, PARP, cleaved-PARP, cleaved caspase-3, cleaved caspase-9, Bcl-2, Bax, Aurka, p-Aurka, Plk1, p-Plk1, Cdc25c, CDK1, cyclin B1, and Myt1 were regulated by HHT. And the relative mRNA expression level of Aurka, Plk1, Cdc25c, CDK1, cyclin B1, and Myt1 were ascertained by q-PCR assay. The results in vivo experiment showed that HHT can slow down the growth rate of tumors. At the same time, the protein expression levels in vivo were consistent with that in vitro. Collectively, our study provided evidence that HHT could be considered an effective anti-melanoma agent by inducing DNA damage, apoptosis, and cell cycle arrest.

Evodiamine inhibits vasculogenic mimicry in HCT116 cells by suppressing hypoxia-inducible factor 1-alpha-mediated angiogenesis.

Evodiamine (Evo), a quinazoline alkaloid and one of the most typical polycyclic heterocycles, is mainly isolated from Evodia rugulosa. Vasculogenic mimicry (VM) is a newly identified way of angiogenesis during tumor neovascularization, which is prevalent in a variety of highly invasive tumors. The purpose of this study was to investigate the effect and mechanism of Evo on VM in human colorectal cancer (CRC) cells. The number of VM structures was calculated by the three-dimensional culture of human CRC cells. Wound-healing was used to detect the migration of HCT116 cells. Gene expression was detected by reverse transcription-quantitative PCR assay. CD31/PAS staining was used to identify VM. Western blotting and immunofluorescence were used to detect protein levels. The results showed that Evo inhibited the migration of HCT116 cells, as well as the formation of VM. Furthermore, Evo reduced the expression of hypoxia-inducible factor 1-alpha (HIF-1α), VE-cadherin, VEGF, MMP2, and MMP9. In a model of subcutaneous xenotransplantation, Evo also inhibited tumor growth and VM formation. Our study demonstrates that Evo could inhibit VM in CRC cells HCT116 and reduce the expression of HIF-1α, VE-cadherin, VEGF, MMP2, and MMP9.

Metformin Inhibits the Urea Cycle and Reduces Putrescine Generation in Colorectal Cancer Cell Lines.

The urea cycle (UC) removes the excess nitrogen and ammonia generated by nitrogen-containing compound composites or protein breakdown in the human body. Research has shown that changes in UC enzymes are not only related to tumorigenesis and tumor development but also associated with poor survival in hepatocellular, breast, and colorectal cancers (CRC), etc. Cytoplasmic ornithine, the intermediate product of the urea cycle, is a specific substrate for ornithine decarboxylase (ODC, also known as ODC1) for the production of putrescine and is required for tumor growth. Polyamines (spermidine, spermine, and their precursor putrescine) play central roles in more than half of the steps of colorectal tumorigenesis. Given the close connection between polyamines and cancer, the regulation of polyamine metabolic pathways has attracted attention regarding the mechanisms of action of chemical drugs used to prevent CRC, as the drug most widely used for treating type 2 diabetes (T2D), metformin (Met) exhibits antitumor activity against a variety of cancer cells, with a vaguely defined mechanism. In addition, the influence of metformin on the UC and putrescine generation in colorectal cancer has remained unclear. In our study, we investigated the effect of metformin on the UC and putrescine generation of CRC in vivo and in vitro and elucidated the underlying mechanisms. In nude mice bearing HCT116 tumor xenografts, the administration of metformin inhibited tumor growth without affecting body weight. In addition, metformin treatment increased the expression of monophosphate (AMP)-activated protein kinase (AMPK) and p53 in both HCT116 xenografts and colorectal cancer cell lines and decreased the expression of the urea cycle enzymes, including carbamoyl phosphate synthase 1 (CPS1), arginase 1 (ARG1), ornithine trans-carbamylase (OTC), and ODC. The putrescine levels in both HCT116 xenografts and HCT116 cells decreased after metformin treatment. These results demonstrate that metformin inhibited CRC cell proliferation via activating AMPK/p53 and that there was an association between metformin, urea cycle inhibition and a reduction in putrescine generation.

Evodiamine inhibits migration and invasion by Sirt1-mediated post-translational modulations in colorectal cancer.

Colorectal cancer (CRC) is one of the most difficult cancers to cure. An important prognostic factor is metastasis, which precludes curative surgical resection. Recent evidences show that Evodiamine (EVO) exerts an inhibitory effect on cancer cell apoptosis, migration, and invasion. In this study, we investigated the effects of EVO on the metastasis of CRC cells in vitro and in vivo. In vitro, wound-healing and transwell assay showed that migration and invasion of HT-29 and HCT-116 CRC cells were inhibited significantly by EVO. Western blot and RT-PCR showed that EVO reduced the expression of matrix metalloproteinase-9 in a dose-dependent manner. In EVO-induced cells, the intracellular NAD+/NADH ratio was increased, the level of Sirt1 was increased, and acetyl-NF-κB P65 was decreased. This process was inhibited by nicotinamide, an inhibitor of Sirt1. In vivo, EVO reduced tumor metastasis markedly. These findings provide evidences that EVO suppresses the migration and invasion of CRC cells by inhibiting the acetyl-NF-κB p65 by Sirt1, resulting in suppression of metalloproteinase-9 expression in vitro and in vivo.

Evodiamine Induces Apoptosis in SMMC-7721 and HepG2 Cells by Suppressing NOD1 Signal Pathway.

Hepatocellular cancer (HCC) is a lethal malignancy with poor prognosis and easy recurrence. There are few agents with minor toxic side effects that can be used for treatment of HCC. Evodiamine (Evo), one of the major bioactive components derived from fructus Evodiae, has long been shown to exert anti-hepatocellular carcinoma activity by suppressing activation of nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK). In addition, in the Nucleotide-Binding Oligomerization Domain 1 (NOD1) pathway, NOD1 could initiate NF-κB-dependent and MAPK-dependent gene transcription. Recent experimental studies reported that the NOD1 pathway was related to controlling development of various tumors. Here we hypothesize that Evo exerts anti-hepatocellular carcinoma activity by inhibiting NOD1 to suppress NF-κB and MAPK activation. Therefore, we proved the anti-hepatocellular carcinoma activity of Evo on HCC cells and detected the effect of Evo on the NOD1 pathway. We found that Evo significantly induced cell cycle arrest at the G2/M phase, upregulated P53 and Bcl-2 associated X proteins (Bax) proteins, and downregulated B-cell lymphoma-2 (Bcl-2), cyclinB1, and cdc2 proteins in HCC cells. In addition, Evo reduced levels of NOD1, p-P65, p-ERK, p-p38, and p-JNK, where the level of IκBα of HCC cells increased. Furthermore, NOD1 agonist γ-D-Glu-mDAP (IE-DAP) treatment weakened the effect of Evo on suppression of NF-κB and MAPK activation and cellular proliferation of HCC. In an in vivo subcutaneous xenograft model, Evo also exhibited excellent tumor inhibitory effects via the NOD1 signal pathway. Our results demonstrate that Evo could induce apoptosis remarkably and the inhibitory effect of Evo on HCC cells may be through suppressing the NOD1 signal pathway in vitro and in vivo.

[Ginsenoside Rh2 induces apoptosis and autophagy of K562 cells by activating p38].

To study the effect of ginseng saponin Rh2 in inducing apoptosis of human leukemia K562 cells, and explore its mechanism from the aspect of autophagy pathway. CCK-8 assay was used to examine the growth inhibition of human leukemia cell lines K562 treated with ginsenoside Rh2; flow cytometry (FCM) was used to detect cell apoptosis; Hoechst staining was used to observe the changes of cell morphological apoptosis; Acridine and MDC staining were used to detect the effects of the Rh2 on autophagy; Western blot and RT-PCR were used to detect the expression levels of the proteins closely associated with autophagy and apoptosis. In order to study the effect of autophagy in proliferation and apoptosis, we used the autophagy inhibitor (3-MA).CCK-8 indicated that Rh2 at low concentration could effectively inhibit the proliferation of leukemia cellsin dose- and time-dependent manners in K562 cells; FCM indicated that Rh2 induced apoptosis; Hoechest staining showed that K562 cells had typical apoptotic morphological changes by treated Rh2; Acridine and MDC staining showed that Rh2 enhanced the green fluorescence and a large number of acidic autophagy vesicles were present; Western blot and RT-PCR results showed that Rh2 increased the expression levels of Beclin-1, LC3A, LC3B, activated Caspase-3 and p-p38 in K562 cells; application of autophagy inhibitors(3-MA) could weaken the inhibition effect of Rh2 on proliferation and induction effect on apoptosis in K562 cells. Ginsenoside Rh2 inhibited the proliferation and induced apoptosis probably through activating p-p38, and inducing cell autophagy signaling pathway in K562 cells.

[Ginsenoside Rh2-induced inhibition of histone deacetylase 6 promotes K562 cells autophagy and apoptosis in vivo].

To study the in vivo inhibition effect of ginsenoside Rh2 on humanleukemia cells, and explore its mechanism from autophagy and apoptosis aspects, human leukemia K562 cells allograft tumor models were applied, and after administration of ginsenosides Rh2 by gavage, the tumor diameter, volume and inhibitory rate were measured, and the anti-tumor activity of ginsenosides Rh2 was observed. The levels of HAT and HDAC in tumor tissues were detected by chemical colorimetry assay, and expressions of HDAC1, HDAC2, HDAC3, HDAC4, HDAC5 and HDAC6 were detected by Western blotting assay. The expression levels of vital genes closely associated with autophagy and mRNA expressions of HDAC6 and Hsp90 were detected by Real time-PCR. HE staining was used to observe apoptosis, and immunohistochemistry was used to detect the protein expressions of HDAC6, Hsp90 and activated caspases 3. The results showed that ginsenoside Rh2 could inhibit the growth of k562 cells allograft tumor, with a tumor inhibition rate up to 53.10%. Ginsenoside Rh2 could significantly decrease HDAC activity and decrease the expressions of HDAC1, HDAC2 and HDAC6, and inhibit the expressions of HDAC6 and HSP90, increase the expressions of vital autophagy genes (beclin-1, LC3A and LC3B). Histopathological results showed that ginsenosides Rh2 could significantly increase the tumor apoptosis. Therefore, ginsenoside Rh2 had good anti-tumor effect in vivo, and the mechanism maybe associated with regulating autophagy and apoptosis through HDAC6 and Hsp90 pathways and inhibiting the in vivo proliferation of tumor cells.

Evodiamine Induces Apoptosis and Inhibits Migration of HCT-116 Human Colorectal Cancer Cells.

Evodiamine (EVO) exhibits strong anti-cancer effects. However, the effect of EVO on the human colorectal cancer cell line HCT-116 has not been explored in detail, and its underlying molecular mechanisms remain unknown. In the present study, cell viability was assessed by Cell Counting Kit-8 (CCK-8). Cell cycle and apoptosis were measured by flow cytometry, and morphological changes in the nucleus were examined by fluorescence microscopy and Hoechst staining. Cell motility was detected by Transwell assay. ELISA was used to assess the protein levels of autocrine motility factor (AMF) in the cell supernatant, and protein expression was determined by Western blotting. Our results showed that EVO inhibited the proliferation of HCT-116 cells, caused accumulation of cells in S and G2/M phases, and reduced the levels of the secreted form of AMF. The protein levels of tumor suppressor protein (p53), Bcl-2 Associated X protein (Bax), B cell CLL/lymphoma-2 (Bcl-2), phosphoglucose isomerase (PGI), phosphorylated signal transducers and activators of transcription 3 (p-STAT3) and matrix metalloproteinase 3 (MMP3) were altered in cells treated with EVO. Taken together, our results suggest that EVO modulates the activity of the p53 signaling pathway to induce apoptosis and downregulate MMP3 expression by inactivating the JAK2/STAT3 pathway through the downregulation of PGI to inhibit migration of HCT-116 human colorectal cancer cells.

Ganoderic acids alleviate atherosclerosis by inhibiting macrophage M1 polarization via TLR4/MyD88/NF-κB signaling pathway.

BACKGROUND AND AIMS: Atherosclerosis (AS) is a chronic inflammatory disease characterized by lipid infiltration and plaque formation in blood vessel walls. Ganoderic acids (GA), a class of major bioactive compounds isolated from the Chinese traditional medicine Ganoderma lucidum, have multiple pharmacological activities. This study aimed to determine the anti-atherosclerotic effect of GA and reveal the pharmacological mechanism. METHODS: ApoE-/- mice were fed a high-cholesterol diet and treated with GA for 16 weeks to induce AS and identify the effect of GA. Network pharmacological analysis was performed to predict the anti-atherosclerotic mechanisms. An invitro cell model was used to explore the effect of GA on macrophage polarization and the possible mechanism involved in bone marrow dereived macrophages (BMDMs) and RAW264.7 cells stimulated with lipopolysaccharide or oxidized low-density lipoprotein. RESULTS: It was found that GA at 5 and 25 mg/kg/d significantly inhibited the development of AS and increased plaque stability, as evidenced by decreased plaque in the aorta, reduced necrotic core size and increased collagen/lipid ratio in lesions. GA reduced the proportion of M1 macrophages in plaques, but had no effect on M2 macrophages. In vitro experiments showed that GA (1, 5, 25 µg/mL) significantly decreased the proportion of CD86+ macrophages and the mRNA levels of IL-6, IL-1ß, and MCP-1 in macrophages. Experimental results showed that GA inhibited M1 macrophage polarization by regulating TLR4/MyD88/NF-κB signaling pathway. CONCLUSIONS: This study demonstrated that GA play an important role in plaque stability and macrophage polarization. GA exert the anti-atherosclerotic effect partly by regulating TLR4/MyD88/NF-κB signaling pathways to inhibit M1 polarization of macrophages. Our study provides theoretical basis and experimental data for the pharmacological activity and mechanisms of GA against AS.

The anti-hepatocellular carcinoma effects of polysaccharides from Ganoderma lucidum by regulating macrophage polarization via the MAPK/NF-κB signaling pathway.

The response of macrophages to environmental signals demonstrates its heterogeneity and plasticity. After different forms of polarized activation, macrophages reach the M1 or M2 activation state according to their respective environment. Ganoderma lucidum polysaccharide (GLPS) is a major bioactive component of Ganoderma lucidum, a well-known medicinal mushroom. Although the immunomodulatory and anti-tumor effects of GLPS have been proven, GLPS's effect on inhibiting hepatocellular carcinoma (HCC) by regulating macrophage polarization is little known. Our data showed that GLPS notably inhibited the growth of a Hepa1-6 allograft. The expression of M1 marker CD86 was higher in the tumor tissue of the GLPS treatment group than in the control group in vivo. In vitro, the phagocytic activity and NO production of macrophages were increased by GLPS treatment. Moreover, it was discovered that GLPS was able to increase the expression of the M1 phenotype marker CD86, iNOS, and pro-inflammatory cytokines comprising IL-12a, IL-23a, IL-27 and TNF-α, but inhibited macrophage polarization towards the M2 phenotype by decreasing the expression of CD206, Arg-1, and inflammation-related cytokines comprising IL-6 and IL-10. The data suggest that GLPS may regulate macrophage polarization. Mechanistically, GLPS increased the phosphorylation of MEK and ERK. In addition, the phosphorylation of IκBα and P65 was increased by GLPS treatment. These data showed that GLPS can regulate the MAPK/NF-κB signaling pathway responsible for M1 polarization. In a nutshell, our research puts forward a new application of GLPS in anti-HCC treatment by regulating macrophage polarization through activating MAPK/NF-κB signaling.

Brusatol Inhibits Proliferation and Metastasis of Colorectal Cancer by Targeting and Reversing the RhoA/ROCK1 Pathway.

Brusatol (BRU) is an important compound extracted from Brucea javanica oil, whose pharmacological effects are able to induce a series of biological effects, including inhibition of tumor cell growth, anti-inflammatory, antiviral, and antitumor. Currently, there are so few studies about the brusatol effects on colorectal cancer that its anticancer mechanism has not been clearly defined. In this study, we made an in-depth investigation into the brusatol effect towards the proliferation and metastasis of colon cancer and the possible mechanism. The inhibitory effect of BRU on the proliferation of colorectal cancer cells was unveiled via CCK-8 method and colony formation assay, while the inhibitory effect of BRU on migration and invasion of colorectal cancer cells was revealed by scratch assay and transwell assay. In addition, Western blot results also revealed that BRU inhibited not only the expressions of RhoA and ROCK1 but also the protein expressions of EMT-related markers e-cadherin, N-cadherin, Vimentin, MMP2, and MMP9 in colon cancer cells. Through the xenotransplantation model, our in vivo experiment further verified the antitumor effect of BRU on colon cancer cells in vitro, and the results were consistent with the protein expression trend. In conclusion, BRU may inhibit the proliferation and metastasis of colorectal cancer by influencing EMT through RhoA/ROCK1 pathway.

Evodiamine inhibits proliferation and promotes apoptosis of hepatocellular carcinoma cells via the Hippo-Yes-Associated Protein signaling pathway.

AIMS: Dysfunction of the Hippo-Yes-Associated Protein (YAP) signaling pathway is known to be associated with hepatocellular carcinoma (HCC). Evodiamine (Evo), a plant-derived bioactive alkaloid, exerts inhibitory effects on cancer. However, the precise influence of Evo on HCC and its potential effects on Hippo-YAP signaling have yet to be ascertained. Here, the effects of Evo on cell proliferation and apoptosis were evaluated using HCC cell lines (HepG2 and Bel-7402) and nude mice with xenograft tumors. We further investigated whether Evo exerts anti-HCC activity through effects on Hippo-YAP signaling in vitro with the aid of XMU-MP-1, an inhibitor of the key component of this pathway, mammalian sterile 20-like kinase 1/2. MAIN METHODS: Cell proliferation and apoptosis were assessed using 5-ethynyl-2'-deoxyuridine staining, colony formation, flow cytometry, hematoxylin-eosin and dUTP nick-end labeling experiments. Bioinformatics and real-time quantitative polymerase chain reaction (RT-qPCR) arrays were performed to determine the associations among Evo, HCC progression and the Hippo-YAP pathway. The expression patterns of components of Hippo-YAP signaling and apoptotic genes were further examined via RT-qPCR and immunoblotting. KEY FINDINGS: Evo inhibited proliferation and promoted apoptosis of HCC cell lines in vitro, and attenuated xenograft tumor formation in nude mice in vivo. Mechanistically, Evo treatment stimulated the Hippo-YAP signaling pathway. In vitro, the effects of Evo on HCC cell proliferation and apoptosis were alleviated by XMU-MP-1. SIGNIFICANCE: Our collective results revealed that the anti-HCC effects of Evo were correlated with the Hippo-YAP signaling pathway.

20(S)-ginsenoside Rh2 inhibits the proliferation and induces the apoptosis of KG-1a cells through the Wnt/ß-catenin signaling pathway.

Previous research has shown that total saponins of Panax ginseng (TSPG) and other ginsenoside monomers inhibit the proliferation of leukemia cells. However, the effect has not been compared among them. Cell viability was determined by Cell Counting Kit-8 assay, and ultra-structural characteristics were observed under transmission electron microscopy. Cell cycle distribution and apoptosis were determined by flow cytometry (FCM). Real-time fluorescence quantitative­PCR, western blotting and immunofluorescence were used to measure the expression of ß-catenin, TCF4, cyclin D1 and NF-κBp65. ß-catenin/TCF4 target gene transcription were observed by ChIP-PCR assay. We found that 20(S)-ginsenoside Rh2 [(S)Rh2] inhibited the proliferation of KG-1a cells more efficiently than the other monomers. Moreover, (S)Rh2 arrested KG-1a cells in the G0/G1 phase and induced apoptosis. In addition, the levels of ß-catenin, TCF4, cyclin D1 mRNA and protein were decreased. The ChIP-PCR showed that (S)Rh2 downregulated the transcription of ß-catenin/TCF4 target genes, such as cyclin D1 and c-myc. These results indicated that (S)Rh2 induced cell cycle arrest and apoptosis through the Wnt/ß-catenin signaling pathway, demonstrating its potential as a chemotherapeutic agent for leukemia therapy.

Anticancer effect of 20(S)-ginsenoside Rh2 on HepG2 liver carcinoma cells: Activating GSK-3ß and degrading ß-catenin.

20(S)-ginsenoside Rh2 [(S)Rh2] possesses potential to prevent cancer in vitro as well as in vivo, but the underlying mechanism is still unknown. First, we infected HepG2 cells with lentivirus which carries ß­catenin. We detected the pharmacological effects of (S)Rh2 on HepG2 and HepG2­ß­catenin cells and found that the IC50 of (S)Rh2 exposure on HepG2-ß-catenin cells was higher than HepG2 cells. Flow cytometry (FCM) indicated that (S)Rh2 could be arrested in G0/G1 phase and induce early apoptosis in HepG2 and HepG2­ß­catenin cells. Second, ELISA kit was used to check the activity of glycogen synthase kinase­3ß (GSK­3ß), which was upregulated by (S)Rh2. GSK­3ß inhibitor BIO, was used to verify that (S)Rh2 activated GSK­3ß. PCR and western blotting results indicated that (S)Rh2 could degrade the expression of ß­catenin, which combined with TCF in the nucleus and activate transcription of Wnt target genes, such as Bax, Bcl­2, cyclin D1, MMP3, which were checked by chromatin immunoprecipitation (ChIP), PCR and western blotting. The results showed that the expression of Bax mRNA and proteins increased, while the cyclin D1, Bcl­2, MMP3 mRNA and proteins were downregulated in HepG2 and HepG2­ß­catenin cells which was induced by (S)Rh2. By contrast, with the HepG2-ß-catenin + (S)Rh2 group, the expression of other mRNA and proteins in HepG2 + (S)Rh2 group changed significantly. In vivo, experiments were performed using a nude mouse xenograft model to investigate the (S)Rh2 effect. So these results suggested that (S)Rh2 could suppress proliferation, promote apoptosis and inhibit metastasis of HepG2, decrease weight of tumor by downregulating ß­catenin through activating GSK­3ß and the pharmacological effect of (S)Rh2 on HepG2 cells might be weakened by overexpression of ß­catenin.

Induction of Apoptosis in Human Leukemic Cell Lines by Diallyl Disulfide via Modulation of EGFR/ERK/PKM2 Signaling Pathways.

BACKGROUND: Diallyl disulfide (DADS) may exert potent anticancer action both in vitro and in vivo. Although its effects on cancer are significant, the underlying mechanisms remain unknown. In this study, we sought to elucidate possible links between DADS and pyruvate kinase (PKM2). MATERIALS AND METHODS: KG1α, a leukemia cell line highly expressing PKM2 was used with a cell counting kit (CCK)-8 and flow cytometry (FCM) to investigate the effects of DADS. Relationships between PKM2 and DADS associated with phosphorylation of EGFR, ERK1/2 and MEK, were assessed by western blot analysis. RESULTS: In KG1α cells highly expressing PKM2, we found that DADS could affect proliferation, apoptosis and EGFR/ERK/PKM2 signaling pathways, abrogating EGF-induced nuclear accumulation of PKM2. CONCLUSIONS: These results suggested that DADS suppressed the proliferation of KG1α cells, providing evidence that its proapoptotic effects are mediated through the inhibition of EGFR/ERK/PKM2 signaling pathways.

Ginsenoside 20(s)-Rh2 as potent natural histone deacetylase inhibitors suppressing the growth of human leukemia cells.

BACKGROUND AND OBJECTIVE: Activation and abnormal expression of histone deacetylase (HDAC) which is important target for cancer therapeutics are related to the occurrence of human leukemia. 20(s)-Ginsenoside Rh2 (20(s)-Rh2) may be a potential HDAC inhibitor (HDACi) of leukemia, but the mechanism has not been reported. METHODS: The cell proliferation and apoptosis was assessed in cultured K562 and KG-1α cells. The protein expression was measured with immunoblotting. The activities of HDAC and histone acetyltransferase (HAT) were measured with BCA. In vivo experiments were performed on naked mice carrying K562 cells for assessment of tumor growth, apoptosis, protein expression, and HDAC/HAT activities. RESULTS: 20(s)-Rh2 effectively induced cell cycle arrest at G0/G1 phase and apoptosis in K562 and KG1-α cells, decreased the levels of proteins associated with cell proliferation (Cyclin D1, Bcl-2, ERK, p-ERK) and activated pro-apoptotic proteins (Bax, cleaved Caspase-3, p38, p-p38, JNK, p-JNK). 20(s)-Rh2 down-regulated HDAC1, HDAC2, HDAC6, increased histone H3 acetylation and HAT activity. Moreover, 20(s)-Rh2 inhibited the growth of human leukemia xenograft tumors in vivo. CONCLUSION: 20(s)-Rh2 inhibited the proliferation of K562 and KG1-α cell by reducing the expression and activity of HDACs, increasing histone acetylation, and regulating key proteins in the downstream signaling pathways. Therefore, 20(s)-Rh2 could become a potential natural HDACi for chemotherapy of leukemia.

Down-regulation of phosphoglucose isomerase/autocrine motility factor enhances gensenoside Rh2 pharmacological action on leukemia KG1α cells.

AIMS AND BACKGROUND: Ginsenoside Rh2, which exerts the potent anticancer action both in vitro and in vivo, is one of the most well characterized ginsenosides extracted from ginseng. Although its effects on cancer are significant, the underlying mechanisms remain unknown. In this study, we sought to elucidate possible links between ginsenoside Rh2 and phosphoglucose isomerase/autocrine motility factor (PGI/AMF). METHODS: KG1α, a leukemia cell line highly expressing PGI/AMF was assessed by western blot analysis and reverse transcription- PCR (RT-PCR) assay after transfection of a small interfering (si)-RNA to silence PGI/AMF. The effect of PGI/ AMF on proliferation was measured by typan blue assay and antibody array. A cell counting kit (CCK)-8 and flow cytometry (FCM) were adopted to investigate the effects of Rh2 on PGI/AMF. The relationships between PGI/AMF and Rh2 associated with Akt, mTOR, Raptor, Rag were detected by western blot analysis. RESULTS: KG1α cells expressed PGI/AMF and its down-regulation significantly inhibited proliferation. The antibody array indicated that the probable mechanism was reduced expression of PARP, State1, SAPK/JNK and Erk1/2, while those of PRAS40 and p38 were up-regulated. Silencing of PGI/AMF enhanced the sensibility of KG1α to Rh2 by suppressing the expression of mTOR, Raptor and Akt. CONCLUSION: These results suggested that ginsenoside Rh2 suppressed the proliferation of KG1α, the same as down-regulation of PGI/AMF. Down-regulation of PGI/ AMF enhanced the pharmacological effects of ginsenoside Rh2 on KG1α by reducing Akt/mTOR signaling.

Ginsenoside Rg1 induces apoptosis through inhibition of the EpoR-mediated JAK2/STAT5 signalling pathway in the TF-1/ Epo human leukemia cell line.

Ginsenoside Rg1 is one effective anticancer and antioxidant constituent of total saponins of Panax ginseng (TSPG), which has been shown to have various pharmacological effects. Our previous study demonstrated that Rg1 had anti-tumor activity in K562 leukemia cells. The aim of this study was designed to investigate whether Rg1 could induce apoptosis in TF-1/Epo cells and further to explore the underlying molecular mechanisms. Here we found that Rg1 could inhibit TF-1/Epo cell proliferation and induce cell apoptosis in vitro in a concentration and time dependent manner. It also suppressed the expression of EpoR on the surface membrane and inhibited JAK2/STAT5 pathway activity. Rg1 induced up-regulation of Bax, cleaved caspase-3 and C-PAPR protein and down-regulation of Bcl-2 and AG490, a JAK2 specific inhibitor, could enhance the effects of Rg1. Our studies showed that EpoR-mediated JAK2/STAT5 signaling played a key role in Rg1-induced apoptosis in TF-1/Epo cells. These results may provide new insights of Rg1 protective roles in the prevention a nd treatment of leukemia.

Effect of trichostatin A on anti HepG2 liver carcinoma cells: inhibition of HDAC activity and activation of Wnt/ß-Catenin signaling.

PURPOSE: To investigate the effect of deacetylase inhibitory trichostatin A (TSA) on anti HepG2 liver carcinoma cells and explore the underlying mechanisms. MATERIALS AND METHODS: HepG2 cells exposed to different concentrations of TSA for 24, 48, or 72h were examined for cell growth inhibition using CCK8, changes in cell cycle distribution with flow cytometry, cell apoptosis with annexin V-FTIC/PI double staining, and cell morphology changes under an inverted microscope. Expression of ß-catenin, HDAC1, HDAC3, H3K9, CyclinD1 and Bax proteins was tested by Western blotting. Gene expression for ß-catenin, HDAC1and HDAC3 was tested by q-PCR. ß-Catenin and H3K9 proteins were also tested by immunofluorescence. Activity of Renilla luciferase (pTCF/LEF-luc) was assessed using the Luciferase Reporter Assay system reagent. The activity of total HDACs was detected with a HDACs colorimetric kit. RESULTS: Exposure to TSA caused significant dose-and time-dependent inhibition of HepG2 cell proliferation (p<0.05) and resulted in increased cell percentages in G0/ G1 and G2/M phases and decrease in the S phase. The apoptotic index in the control group was 6.22±0.25%, which increased to 7.17±0.20% and 18.1±0.42% in the treatment group. Exposure to 250 and 500nmol/L TSA also caused cell morphology changes with numerous floating cells. Expression of ß-catenin, H3K9and Bax proteins was significantly increased, expression levels of CyclinD1, HDAC1, HDAC3 were decreased. Expression of ß-catenin at the genetic level was significantly increased, with no significant difference in HDAC1and HDAC3 genes. In the cytoplasm, expression of ß-catenin fluorescence protein was not obvious changed and in the nucleus, small amounts of green fluorescence were observed. H3K9 fluorescence protein were increased. Expression levels of the transcription factor TCF werealso increased in HepG2 cells following induction by TSA, whikle the activity of total HDACs was decreased. CONCLUSIONS: TSA inhibits HDAC activity, promotes histone acetylation, and activates Wnt/ß-catenin signaling to inhibit proliferation of HepG2 cell, arrest cell cycling and induce apoptosis.