Oridonin-induced mitochondria-dependent apoptosis in esophageal cancer cells by inhibiting PI3K/AKT/mTOR and Ras/Raf pathways.

Oridonin, an active diterpenoid isolated from Rabdosia rubescens, has been reported for its antitumor activity on several cancers. However, its effect on human esophageal cancer remains unclear. In this study, we demonstrated that oridonin could inhibit the growth of human esophageal cancer cells both in vitro and in vivo. Oridonin not only suppressed the proliferation, but also induced cell cycle arrest and mitochondrial-mediated apoptosis in KYSE-30, KYSE-150, and EC9706 cells with dose-dependent manner. Further mechanism studies revealed that oridonin led cell cycle arrest in esophageal cancer cells via downregulating cell cycle-related proteins, such as cyclin B1 and CDK2, while upregulating p53 and p21. Oridonin also increased proapoptotic protein Bax and reduced antiapoptotic protein Bcl-2, as well as the increased expression of cleaved caspase-3, -8, and -9. In addition, oridonin treatment could significantly inhibit the PI3K/Akt/mTOR and Ras/Raf signaling pathway. In vivo results further demonstrated that oridonin treatment markedly inhibited tumor growth in the esophageal cancer xenograft mice model. Taken together, these results suggest that oridonin may be a potential anticancer agent for the treatment of esophageal cancer.

Synthesis, Spectroscopic Study and Radical Scavenging Activity of Kaempferol Derivatives: Enhanced Water Solubility and Antioxidant Activity.

Kaempferol (Kae) is a natural flavonoid with potent antioxidant activity, but its therapeutic use is limited by its low aqueous solubility. Here, a series of Kae derivatives were synthesized to improve Kae dissolution property in water and antioxidant activity. These compounds included sulfonated Kae (Kae-SO3), gallium (Ga) complexes with Kae (Kae-Ga) and Kae-SO3 (Kae-SO3-Ga). The compound structures were characterized by high-resolution mass spectrometry (HRMS), nuclear magnetic resonance (NMR) spectroscopy, ultraviolet-visible (UV-Vis) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy and thermal methods (TG/DSC). The results showed that a sulfonic group (-SO3) was successfully tethered on the C3' of Kae to form Kae-SO3. And in the metal complexation, 4-CO and 3-OH of the ligand participated in the coordination with Ga(III). The metal-to-ligand ratio 1:2 was suggested for both complexes. Interestingly, Kae-SO3-Ga was obviously superior to other compounds in terms of overcoming the poor water-solubility of free Kae, and the solubility of Kae-SO3-Ga was about 300-fold higher than that of Kae-Ga. Furthermore, the evaluation of antioxidant activities in vitro was carried out for Kae derivatives by using α,α-diphenyl-ß-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzo-thiazoline-6-sulfonic acid) diammonium salt (ABTS) free radical scavenging. The results showed that Kae-SO3-Ga was also optimal for scavenging free radicals in a dose-dependent manner. These data demonstrate that sulfonate kaempferol-gallium complex has a promising future as a potential antioxidant and as a potential therapeutic agent for further biomedical studies.

Synthesis, characterization and anticancer activity of kaempferol-zinc(II) complex.

According to the previous studies, the anticancer activity of flavonoids could be enhanced when they are coordinated with transition metal ions. In this work, kaempferol-zinc(II) complex (kaempferol-Zn) was synthesized and its chemical properties were characterized by UV-VIS, FT-IR, (1)H NMR, elemental analysis, electrospray mass spectrometry (ES-MS) and fluorescence spectroscopy, which showed that the synthesized complex was coordinated with a Zn(II) ion via the 3-OH and 4-oxo groups. The anticancer effects of kaempferol-Zn and free kaempferol on human oesophageal cancer cell line (EC9706) were compared. MTT results demonstrated that the killing effect of kaempferol-Zn was two times higher than that of free kaempferol. Atomic force microscopy (AFM) showed the morphological and ultrastructural changes of cellular membrane induced by kaempferol-Zn at subcellular or nanometer level. Moreover, flow cytometric analysis indicated that kaempferol-Zn could induce apoptosis in EC9706 cells by regulating intracellular calcium ions. Collectively, all the data showed that kaempferol-Zn might be served as a kind of potential anticancer agent.

Mouse A6-positive hepatic oval cells derived from embryonic stem cells.

Oval cells have a potential to differentiate into a variety of cell lineages including hepatocytes and biliary epithelia. Several models have been established to activate the oval cells by incorporating a variety of toxins and carcinogens, alone or combined with surgical treatment. Those models are obviously not suitable for the study on human hepatic oval cells. It is necessary to establish a new and efficient model to study the human hepatic oval cells. In this study, the hepatocyte growth factor (HGF) and epidermal growth factor (EGF) were used to induce differentiation of mouse embryonic stem (ES) cells into hepatic oval cells. We first confirmed that hepatic oval cells derived from ES cells, which are bipotential, do exist during the course of mouse ES cells' differentiation into hepatic parenchymal cells. RT-PCR and transmission electron microscopy were applied in this study. The ratio of Sca-1+/CD34+ cells sorted by FACS in the induction group was increased from day 4 and reached the maximum on the day 8, whereas that in the control group remained at a low level. The differentiation ratio of Sca-1+/CD34+ cells in the induction group was significantly higher than that in the control group. About 92.48% of the sorted Sca-1+/CD34+ cells on the day 8 were A6 positive. Highly purified A6+/Sca-1+/CD34+ hepatic oval cells derived from ES cells could be obtained by FACS. The differentiation ratio of hepatic oval cells in the induction group (up to 4.46%) was significantly higher than that in the control group. The number of hepatic oval cells could be increased significantly by HGF and EGF. The study also examined the ultrastructures of ES-derived hepatic oval cells' membrane surface by atomic force microscopy. The ES-derived hepatic oval cells cultured and sorted by our protocols may be available for the future clinical application.

Synthesis and biological evaluation of Germanium(IV)-polyphenol complexes as potential anti-cancer agents.

Germanium (Ge) is considered to play a key role in the pharmacological effects of some medicinal plants. Here, two new Ge(IV)-polyphenol complexes were synthesized and measured for their potential biological activities. The results indicated that these Ge(IV)-polyphenol complexes possessed great anti-oxidative activities, both showing stronger hydroxyl scavenging effects than their corresponding ligands. We also demonstrated the strong intercalating abilities of Ge(IV)-polyphenol complexes into calf thymus-DNA molecules. In addition, these two Ge(IV)-polyphenol complexes showed strong proliferative inhibition effect on HepG2 cancer cells. Moreover, the morphological changes in HepG2 cells induced by Ge(IV)-polyphenol complexes were detected by atomic force microscopy. All these results collectively suggested that Ge(IV)-polyphenol complexes could be served as promising pharmacologically active substances against cancer treatment.

Anti-tumor activity evaluation of novel chrysin-organogermanium(IV) complex in MCF-7 cells.

Chrysin (5,7-dihydroxylflavone, Chry) is a natural product extracted from plants, honey, and propolis. In this work, a novel chrysin-organogermanium(IV) complex (Chry-Ge) with enhanced anticancer activities was synthesized, and its potential anticancer effects against cancer cells were measured using various methods. MTT results showed that Chry-Ge had significant inhibition effects on the proliferation of MCF-7, HepG2 and Colo205 human cancer cell lines in a dose-dependent manner while had little cytotoxic effects on MCF-10A human normal cells (MCF-10A cells) with the same treatment of Chry-Ge. These results suggested that Chry-Ge possessed enhanced anticancer effects and high selectivity between cancer cells and normal cells. The immuno-staining results showed that the nuclei of MCF-7 cells represented a total fragmented morphology and a disorganized cytoskeletal network in MCF-7 cells after Chry-Ge treatment. Besides, atomic force microscopy (AFM) was applied to detect the changes of ultrastructural and biomechanical properties of MCF-7 cellular membrane induced by Chry-Ge. The AFM data indicated that Chry-Ge treatment directly caused the decrease of cell rigidity and adhesion force of MCF-7 cells, suggesting that membrane toxicity might be one of the targets for Chry-Ge in MCF-7 cells. Moreover, the fluorescence-based flow cytometric analysis demonstrated that Chry-Ge could induce apoptosis in MCF-7 cells in ROS-dependent mitochondrial pathway. All results collectively showed that Chry-Ge could be as a promising anticancer drug for cancer therapy.

[Roles of E-cadherin in enhancing the in vitro differentiation of hepatocytes from murine embryonic stem cells].

OBJECTIVE: To investigate the roles of E-cadherin (E-cad) in enhancing the in vitro differentiation of hepatocytes from murine embryonic stem cells (ESCs). METHODS: Exogenous E-cad was transfected into BALB/c murine ESCs to enable its stable expression. Then hepatic differentiation from E-cad-ESCs was induced by such growth factors as hepatocyte growth factor (HGF), fibroblast growth factor (FGF) and transforming growth factor (TGF). And the expressions of hepatic markers ALB, TAT, Cyp7a1 and urea were detected. The morphology of hepatic differentiation was observed under microscopy. RESULTS: E-cad expression gradually decreased in normal ESC differentiation, but was stably expressed in E-cad-ESCs. In E-cad-ESC group, hepatic markers ALB, TAT and CYP7a1 were expressed earlier or higher than that in normal ESC group, and the concentrations of ALB and urea were significantly higher than that in normal ESC group. The adhesion of the differentiated E-cad-ESCs was significantly enhanced compared with the normal ESCs. They maintained close connections and multidimensional growth. Cell number of hepatocytes from ESC increased significantly in E-cad-ESC group. CONCLUSION: E-cad enhances the hepatic differentiation of ESC by increasing the number of differentiated cells and increasing the synthetic capacity of ALB and urea.

Oridonin exhibits anti-angiogenic activity in human umbilical vein endothelial cells by inhibiting VEGF-induced VEGFR-2 signaling pathway.

Oridonin has been found to be a potential anti-angiogenesis agent. However, its functional targets and the underlying mechanisms are still vague. In vitro studies we found that oridonin not only inhibited VEGF-induced cell proliferation, migration and tube formation but also caused G2/M phase arrest and triggered cellular apoptosis in HUVECs. In mechanistic studies revealed that oridonin exhibited the anti-angiogenic potency, at least in part, through the down-regulation of VEGFR2-mediated FAK/MMPs, mTOR/PI3K/Akt and ERK/p38 signaling pathways which led to reduced invasion, migration, and tube formation in HUVECs. Our results could provide evidence that oridonin exerts strong anti-angiogenesis activities via specifically targeting VEGFR2 and its signaling pathway.

[Nanogold inhibits angiogenesis and growth of liver cancer: experiment with mice].

OBJECTIVE: To investigate the effects of nanogold in inhibition of angiogenesis and growth of liver cancer cells. METHODS: Nanogold was co-incubated with VEGF165 and VDGF121 respectively. Atomic force microscopy (AFM) was used to observe the changes of the form of the particles. Human umbilical vascular endothelial cells (HUVEC) were serum-starved for 24 hours, then co-cultured with VEGF165 + nanogold or VEGF121 + nanogold for 24 h. ATM was used to observe the ultrastructure of the cells. Another HUVEC were serum-starved for 24 hours and then cultured with VEGF165 (10 microg/L) 100 microl + nanogold 125, 250, and 500 nmol/L 100 microl respectively for 5 min. Then Western blotting was used to detect the phosphorylation protein of phospholipase C (PLC)-gamma1 on VEGFR-2. Hepatocellular cancer cells of the line H22 were injected subcutaneously into the right armpit of 20 Balb/c nude mice. When the size of transplanted tumor reached about 8 mm, the mice were divided into 2 equal groups: experimental group undergoing injection of nanogold into the tumor once a day for 8 days, and control group injected with normal saline. On day 14 the mice were sacrificed with the liver tumors taken out to measure the size and weight. The microvascular density (MVD) of tumor was determined by immunohistochemical staining. RESULTS: ATM showed that acted with VEGF165, the size of nanogold became over 30 nm. Treated with VEGF165 the HUVEC became larger with obvious pseudopodium. However, such changes were obviously milder in those HUVEC treated with nanogold + VEGF165. The PLC-gamma1 phosphorylation level VEGF receptor-2 was decreased along with the increase of the concentration of nanogold. The MVD of liver cancer tissue in the experimental group was 14.27 +/- 1.08, significantly lower than that of the control group [(23.52 +/- 1.36), P < 0.01]. The mean weight and volume of tumor of the experimental group were (1.39 +/- 0.08) g and (1.37 +/- 0.34) cm(3) respectively, both significantly lower than those of the control group [(2.47 +/- 0.15) g and (2.49 +/- 0.78) cm(3) respectively, both P < 0.05] with a tumor growth inhibition rate of 43.72%. CONCLUSION: Nanogold significantly inhibits the angiogenesis and growth of liver cancer cells with the possible mechanism that nanogold inhibits the VEGF165-induced signaling.

[Immobilization of anti-transferrin on nano-gold and its immune recognition of transferrin].

A novel strategy based on antigen-antibody interaction was developed by means of backfilling transferrin on antibody functionalized gold nanoparticles surfaces in the present study. Nano gold particles were immobilized with cysteamine layer by self-assembly, whose surfaces were chemically coupled with anti-transferrin antibodies by using EDCX, forming the anti-transferrin-Au immuno-probes. The particles and the nano-probes were characterized by the integrated tools of resonance Rayleigh scattering (RRS), UV-Vis absorption spectra, transmission electron microscopy (TEM) and laser light scattering. The result showed that the nano-probe with the ability of specific recognition of transferrin had good immune activity. The RRS peak at 470 nm was amplified obviously by using this signal amplification, and the antigen recognition was monitored via the enhancement of 470 nm RRS intensity when this binding event occurred. The result showed that the amplification strategy led to a dramatic improvement of the detection sensitivity of transferrin, and the detection of transferrin featured a linear range of 0.85 to 33.9) x 10(-10) mol x L(-1) with the detection limit of 8.5 x 10(-11) mol x L(-1).

Live morphological analysis of taxol-induced cytoplasmic vacuolization [corrected] in human lung adenocarcinoma cells.

Taxol (paclitaxel), one of the most active cancer chemotherapeutic agents, can cause programmed cell death (PCD) and cytoplasmic vacuolization. The objective of this study was to analyze the morphological characteristics induced by taxol. Human lung adenocarcinoma (ASTC-a-1) cells were exposed to various concentration of taxol. CCK-8 was used to assay the cell viability. Atomic force microscopy (AFM), plasmid transfection and confocal fluorescence microscopy were performed to image the cells morphological change induced by taxol. Fluorescence resonance energy transfer (FRET) was used to monitor the caspase-3 activation in living cells during taxol-induced cell death. Cells treated with taxol exhibited significant swelling and cytoplasmic vacuolization which may be due to endoplasmic reticulum (ER) vacuolization. Caspase-3 was not activated during taxol-induced cytoplasmic vacuolization and cell death. These findings suggest that taxol induces caspase-3-independent cytoplasmic vacuolization, cell swelling and cell death through ER vacuolization.

Functional graphene oxide as cancer-targeted drug delivery system to selectively induce oesophageal cancer cell apoptosis.

Graphene oxides (GO) is a promising building material to fabricate desired drug delivery system due to its excellent physicochemical properties. In this study, an innovative nano-drug (Ori@GE11-GO) was constructed based on GE11 peptide functionalized GO for targeted delivery of oridonin to realize the specific recognition of tumour cells and enhance anticancer efficiency. GE11 surface modification onto GO significantly increased the cellular uptake of GO in EGFR overexpressed oesophageal cancer cells (KYSE-30 and EC109 cells) than that of normal cells, indicating the EGFR targeting effects of Ori@GE11-GO. The internalized Ori@GE11-GO could accumulate into lysosomes and significantly inhibit the viability of cancer cells. Moreover, Ori@GE11-GO could effectively induce KYSE-30 and EC109 cells cycle arrest, apoptosis, mitochondrial membrane potential (△Ψm) disruption through the activation of apoptotic signalling pathways and the inhibition of EGFR/Ras/Raf/MEK/ERK signalling pathway, showing potential use of Ori@GE11-GO for cancer treatment. Taken together, this study demonstrates a good strategy for the construction of bio-functionalized GO drug delivery nanosystem to improve the cancer targeting efficiency of anticancer medicines.

Chinese herb medicine matrine induce apoptosis in human esophageal squamous cancer KYSE-150 cells through increasing reactive oxygen species and inhibiting mitochondrial function.

Matrine, as a natural alkaloid isolated from the traditional herb medicine sophora flavescens, has been proved to possess excellent biological activities, including anticancer effects. Now, this research aims to assess the anticancer activities and the mechanism of matrine against esophageal cancer cells, we investigated the proliferative inhibition, apoptosis induction, as well as the underlying mechanism of matrine on esophageal cancer KYSE-150 cells. It was found that matrine could suppress KYSE-150 cell proliferation and significantly mediate cell apoptosis in a dose-dependent relation by increasing intracellular reactive oxygen species level and triggering mitochondrial membrane potential disruption. More precise mechanism studies demonstrated that matrine could up-regulate the expression of Bax proteins and down-regulate the expression of Bcl-2 proteins, as well as the activation about caspase-3, 8 and 9 in KYSE-150 cells. The morphological analysis of KYSE-150 cells exhibited that matrine could destroy the F-actin and nuclei structures and induce morphological damage with increased surface height distribution and roughness of cell membrane. These results not only demonstrated the potential anticancer activity mechanism of matrine at nanoscale, but also provide preliminary guidance for the treatment of esophageal cancer using matrine.

High-level expression of acidic partner-mediated antimicrobial peptide from tandem genes in Escherichia coli.

A novel strategy for constructing multiple joined genes of acidic partner-mediated antimicrobial peptide is described. This strategy allows the expression of antimicrobial peptide by Escherichia coli in a stable form and with high yield. Cecropin A (1-8)-melittin (1-10) (CAME) hybrid peptide was selected as a model of antimicrobial peptide. An acidic fragment from magainin intervening sequence was fused to the antimicrobial peptide as a partner to neutralize the lethal effects on the host cells. Multiple copies of the fusion peptide gene were tandemly linked and cloned into the expression vector pET21a. Multimers were expressed at high levels, reaching up to 36% of total cell proteins, and expression levels were proportional to the degree of multimerization. The fusion proteins were mainly expressed as inclusion bodies, probably owing to cysteine residues in the multimers. The target CAME peptide was obtained by cleaving the multimers with cyanogen bromide and purified by cation-exchange chromatography. Recombinant CAME peptide showed strong antimicrobial activities against both Gram-negative and -positive bacteria. These results might provide an efficient solution for high-level expression of various kinds of antimicrobial peptides that are toxic to the host.

[Curative effects of transplantation of hepatocytes differentiated from embryonic stem cells on treatment of fulminant hepatic failure: experiment with mice].

OBJECTIVE: To investigate the curative effects of transplantation of hepatocytes differentiated from embryonic stem cells (ESCs) on treatment of fulminant hepatic failure (FHF). METHODS: Mouse ESCs transfected with green fluorescent protein were cultured. RT-PCR was used to detect the mRNA expression of alpha-fetoprotein (AFP), transthyretin (TTR), hepatic nuclear factor (HNF), albumin (ALB), glucose-6-phosphate (G6P), and tyrosine aminotransferase (TAT) at different time points. Immunocytochemistry (ICC) was used to detect the expression of AFP, ALB, cytokeratin 8 (CK8), and CK11 in the cells. The morphology and distribution of the cells were observed with microscope. Forty mice were randomly divided into 2 equal groups: ESC transplantation group, undergoing transplantation of ICC positive ESCs (hepatocytes) into the hepatic capsule, and control group, undergoing injection of normal saline in the hepatic capsule. Twenty-four hours later carbon tetrachloride was injected intra-peritoneally to induce FHF. The survival status of the mice was observed. Twenty-four hours later venous blood samples were collected to examine the levels of total bilirubin (TB), alanine aminotransferase (ALT), ALB, blood sugar (BS), and prothrombin time (PT). After the death of the mice, their livers were taken out to undergo microscopy and immunohistochemistry to observe the structure of liver tissue, growth of tumor, and expression of ALB. RESULTS: RT-PCR showed that the mRNA expression of AFP, TTR, HNF, ALB, G6P, and TAT emerged since days 3, 3, 5, 9, and 11 respectively and then gradually increased till day 19. ICC showed that the EB cells began to express AFP since day 7, to express CK8 and CK11 since day 9, and to express ALB since day 11. The ICC-positive cells were consistent with the mouse hepatocytes morphologically and were distributed only in the central and marginal areas of the EB cell community. Injected with carbon tetrachloride, the mice showed manifestations of FHF. However, the symptoms of central nervous system emerged later in the mice implanted with the hepatocytes in comparison with the control mice; 8 of the 20 mice in the transplantation group showed ascites in comparison with 14 in the control group. The mean survival time of the transplantation group was 62 hours, significantly longer than that of the control group (23 hours, P < 0.05). Compare with the normal mice, the FHF mice in both groups showed higher ALT and TB and lower ALB and BS (all P < 0.01), however, the levels of ALT and TB were lower, the level of BS was higher, and PT was shorter significantly in the transplantation group than in the control group (all P < 0.05). Pathology showed that no tumor formation was found in both groups and that the transplanted hepatocytes were incorporated well into the liver parenchymal structure and expressed ALB. CONCLUSION: Hepatocytes originating from ESCs exercise the functions of normal hepatocytes. Transplantation of hepatocytes differentiated from ESCs is able to improve the life quality and lengthen the survival time of FHF mice.

The mechanism of kaempferol induced apoptosis and inhibited proliferation in human cervical cancer SiHa cell: From macro to nano.

Kaempferol has been identified as a potential cancer therapeutic agent by an increasing amount of evidences. However, the changes in the topography of cell membrane induced by kaempferol at subcellular- or nanometer-level were still unclear. In this work, the topographical changes of cytomembrane in human cervical cancer cell (SiHa) induced by kaempferol, as well as the role of kaempferol in apoptosis induction and its possible mechanisms, were investigated. At the macro level, MTT assays showed that kaempferol inhibited the proliferation of SiHa cells in a time- and dose-dependent manner. Flow cytometry analysis demonstrated that kaempferol could induce SiHa cell apoptosis, mitochondrial membrane potential disruption, and intracellular free calcium elevation. At the micro level, fluorescence imaging by laser scanning confocal microscopy (LSCM) indicated that kaempferol could also destroy the networks of microtubules. Using high resolution atomic force microscopy (AFM), we determined the precise changes of cellular membrane induced by kaempferol at subcellular or nanometer level. The spindle-shaped SiHa cells shrank after kaempferol treatment, with significantly increased cell surface roughness. These data showed structural characterizations of cellular topography in kaempferol-induced SiHa cell apoptosis and might provide novel integrated information from macro to nano level to assess the impact of kaempferol on cancer cells, which might be important for the understanding of the anti-cancer mechanisms of drugs. SCANNING 38:644-653, 2016. © 2016 Wiley Periodicals, Inc.

Differentiation of hepatocytes from mouse embryonic stem cells and its significance.

BACKGROUND: There have been lots of important discoveries in the research on embryonic stem (ES) cells; but few studies have been involving in the differentiation and differentiation ratio of hepatic stem cells. To provide a new source of hepatocytes in hepatocytes transplantation and liver tissue engineering, we investigated the differentiation and differentiation ratio of hepatocytes in the ES cells differentiating system in a certain length of time. METHODS: BALB/c ES cells from mice were cultured for differentiation in medium without leukemia inhibitory factor (LIF). During the period of differentiation of ES cells, dual immunofluorescence was performed to analyze the expression of hepatic proteins in cytoplasm such as alpha-fetoprotein (AFP) and albumin (ALB). The count of relative hepatocyte-like cells was analyzed by flow cytometry (FCM) and the hepatic differentiation ratio was obtained. RESULTS: The expression of AFP was first determined at day 7 and that of ALB at day 13. The expressions of AFP and ALB became stronger with the extention of the differentiation time. The hepatic differentiation ratio at day 13 and 21 was 5.5% and 10.4%, respectively. CONCLUSION: ES cells could differentiate into hepatocytes, which should be a new source of hepatocytes in transplantation of hepatocytes and liver engineering.

[Directional differentiation of embryonic stem cells into biliary epithelium cells in vitro: an experiment with mice].

OBJECTIVE: To investigate the mechanism and regulation of differentiation from embryonic stem (ES) cells into biliary epithelium (BE) cells and to find a new source f of BE cells for liver engineering. METHODS: ES cells of BALB/c mice (BALB/c-ES) and ES cells of mice of the line 129 (D3-ES) were cultured in the medium without LIF for 5 days with the result that embryoid bodies (EBs) were developed from the ES cells. For directional differentiation, the EBs were plated onto a 24-well gelatin-coated tissue culture dish and some growth factors, such as transforming growth factor (TGF), acid fibroblast growth factor (aFGF), hepatocyte growth factor (HGF) and epidermal growth factor (EGF) etc were added into the medium successively in the experiment group but not in the control group. The differentiation status was observed by inversion microscope dynamically. The BE cell markers, such as cytokeratin 7 (CK7), cytokeratin 19 (CK19) and gamma-glutamyltransferase (GGT) were detected by immunocytochemistry (ICC) and histochemistry. RESULTS: After the culture for 5 days the ES cells developed into many EBs in the medium without LIF. In the EBs cells clusters, many circular structures appeared on the differentiation day 10. On the days 10 and 13 ICC, CK7 and CK19 began to be expressed respectively. GGT began to be expressed at day 10. CK7, CK19 and GGT were also expressed in the ES cells of the control group, however, appeared remarkably later. CONCLUSION: ES cells can differentiate into BE cells under specific culture condition and the action of growth factors. Such ES cell differentiating system can provide BE cells and may serve as a good new source of differentiated cell types for liver engineering.

[Directed differentiation of Balb/C mouse embryonic stem cells into pancreatic islet-like cell clusters in vitro: observation by atomic force microscope].

OBJECTIVE: To observe the morphological changes of Balb/C mouse embryonic stem cells following directed differentiation into pancreatic islet-like cell clusters (PICC) in vitro using atomic force microscope (AFM). METHODS: Balb/C mouse embryonic stem cells were first cultured into embryonic bodies (EBs) and allowed to differentiate spontaneously for 4 days. The cells were then transferred to gelatin-coated dishes for the EBs to attach and spread on the tissue culture plates, in the course of which a series of cell growth factors such as basic fibroblast growth factor (bFGF), insulin-like growth factor 1 (IGF-1) and nicotinamide were added into the culture medium at specific time points to induce directed differentiation of the stem cells into PICC. Immunocytochemistry was employed to detect the cells positive for insulin and glucagon, which were observed with AFM. RESULTS: The embryonic stem cells developed into cell clusters of different sizes, in which the cells were tightly arranged. Islet B cells were numerous in the center of clusters and darkly stained, but fewer in the peripherals with lighter stains. Islet A cells expressing glucagon were relatively fewer in the cell clusters, found mainly in the peripherals. Scanning of the insulin-positive clusters by AFM revealed large quantity of tissue fibers resembling nerve fibers that formed a reticular structure in disorderly arrangement. Numerous round granules were observed in the cytoplasm of almost identical sizes ranging from 0.5 to 1.0 mum in diameter. CONCLUSION: The cell clusters obtained by directed differentiation are mature in both morphology and function with also well organized structures.

The BH3-mimetic gossypol and noncytotoxic doses of valproic acid induce apoptosis by suppressing cyclin-A2/Akt/FOXO3a signaling.

Previously we reported that valproic acid (VPA) acts in synergy with GOS to enhance cell death in human DU145 cells. However, the underlying mechanism remains elusive. In this study, we observed that such synergistic cytotoxicity of GOS and VPA could be extended to human A375, HeLa, and PC-3 cancer cells. GOS and VPA co-treatment induced robust apoptosis as evidenced by caspase-8/-9/-3 activation, PARP cleavage, and nuclear fragmentation. GOS and VPA also markedly decreased cyclin A2 protein expression. Owing to the reduction of cyclin A2, Akt signaling was suppressed, leading to dephosphorylation of FOXO3a. Consequently, FOXO3a was activated and the expression of its target genes, including pro-apoptotic FasL and Bim, was upregulated. Supporting this, FOXO3a knockdown attenuated FasL and Bim upregulation and apoptosis induction in GOS+VPA-treated cells. Furthermore, blocking proteasome activity by MG132 prevented the downregulation of cyclin A2, dephosphorylation of Akt and FOXO3a, and induction of apoptosis in cells co-treated with GOS and VPA. In mouse model, GOS and VPA combination significantly inhibited the growth of A375 melanoma xenografts. Our findings indicate that GOS and VPA co-treatment induces apoptosis in human cancer cells by suppressing the cyclin-A2/Akt/FOXO3a pathway.