A small molecule induces integrin ß4 nuclear translocation and apoptosis selectively in cancer cells with high expression of integrin ß4.

Increased integrin ß4 (ITGB4) level is accompanied by malignant progression of multiple carcinomas. However, selective therapeutic strategies against cancer cells expressing a high level of ITGB4 have not been reported. Here, for the first time, we report that a chiral small molecule, SEC, selectively promotes apoptosis in cancer cells expressing a high level of ITGB4 by inducing ITGB4 nuclear translocation. Nuclear ITGB4 can bind to the ATF3 promoter region and activate the expression of ATF3, then upregulate the downstream pro-apoptosis genes. Furthermore, SEC promoted the binding of annexin A7 (ANXA7) to ITGB4 and increased ANXA7 GTPase activity. Activated ANXA7 promoted ITGB4 nuclear translocation by triggering ITGB4 phosphorylation at Y1494. SEC also inhibited the growth of xenograft tumors in the avian embryo model. We identified a small molecule, SEC, with selective pro-apoptosis effects on cancer cells with high expression of ITGB4, both in vitro and in vivo, by triggering the binding of ITGB4 and ANXA7, ITGB4 nuclear trafficking, and pro-apoptosis gene expression.

Novel ferrocenyl derivatives exert anti-cancer effect in human lung cancer cells in vitro via inducing G1-phase arrest and senescence.

AIM: To investigate the effects of 7 novel 1-ferrocenyl-2-(5-phenyl-1H-1,2,4-triazol-3-ylthio) ethanone derivatives on human lung cancer cells in vitro and to determine the mechanisms of action. METHODS: A549 human lung cancer cells were examined. Cell viability was analyzed with MTT assay. Cell apoptosis and senescence were examined using Hoechst 33258 and senescence-associated-ß-galactosidase (SA-ß-gal) staining, respectively. LDH release was measured using a detection kit. Cell cycle was analyzed using a flow cytometer. Intracellular ROS level was measured with the 2',7'-dichlorodihydrofluorescein probe. Phosphorylation of p38 was determined using Western blot. RESULTS: Compounds 5b, 5d, and 5e (40 and 80 µmol/L) caused significant decrease of A549 cell viability, while other 4 compounds had no effect on the cells. Compounds 5b, 5d, and 5e (80 µmol/L) induced G1-phase arrest (increased the G1 population by 22.6%, 24.23%, and 26.53%, respectively), and markedly increased SA-ß-gal-positive cells. However, the compounds did not cause nuclear DNA fragmentation and chromatin condensation in A549 cells. Nor did they affect the release of LDH from the cells. The compounds significantly elevated the intracellular ROS level, decreased the mitochondrial membrane potential, and increased p38 phosphorylation in the cells. In the presence of the antioxidant and free radical scavenger N-acetyl-L-cysteine (10 mmol/L), above effects of compounds 5b, 5d, and 5e were abolished. CONCLUSION: The compounds 5b, 5d, and 5e cause neither apoptosis nor necrosis of A549 cells, but exert anti-cancer effect via inducing G1-phase arrest and senescence through ROS/p38 MAP-kinase pathway.

The effect of novel magnetic nanoparticles on vascular endothelial cell function in vitro and in vivo.

Manufactured nanoparticles are currently used for many fields. However, their potential toxicity provides a growing concern for human health. In our previous study, we prepared novel magnetic nanoparticles (MNPs), which could effectively remove heavy metal ions and cationic dyes from aqueous solution. To understand its biocompatibility, we investigated the effect of the nanoparticles on the function of vascular endothelial cells. The results showed that the nanoparticles were taken up by human umbilical vein endothelial cells (HUVECs) and could inhibit cell proliferation at 400 µg/ml. An increase in nitric oxide (NO) production and endothelial nitric oxide synthase (eNOS) activity were induced, which companied with the decrease in caveolin-1 level. The endothelium in the aortic root was damaged and the NO level in serum was elevated after treated mice with 20mg/kg nanoparticles for 3 days, but it was integrated after treated with 5mg/kg nanoparticles. Meanwhile, an increase in eNOS activity and decrease in caveolin-1 level were induced in the endothelium. The data suggested that the low concentration of nanoparticles could not affect the function and viability of VECs. The high concentration of nanoparticles could inhibit VEC proliferation through elevation of the eNOS activity and NO production and thus present toxicity.

Human vascular endothelial cells reduce sphingosylphosphorylcholine-induced smooth muscle cell contraction in co-culture system through integrin ß4 and Fyn.

AIM: In vascular strips, the adjacent endothelial cells modulate the contraction of vascular smooth muscle cells (VSMCs) induced by sphingosylphosphorylcholine (SPC) through nitric oxide (NO). The aim of this study was to elucidate the mechanisms by which vascular endothelial cells (VECs) reduce the SPC-induced contraction of VSMCs in a co-culture system. METHODS: Human umbilical VECs and VSMCs were co-cultured. The VECs were transfected with integrin ß4- or Fyn-specific siRNA. The areas of VSMCs that are involved in cell contractility were quantified using the Leica confocal software and collagen contractility assay. The production of NO in VECs was measured in the cell supernatants using NO Detection Kit. The levels of integrin ß4 and Fyn in VECs and the levels of Rho kinase (ROCK) in VSMC were detected using immunofluorescence assays or Western blots. RESULTS: Co-culture with VECs reduced the contraction of VSMCs induced by SPC (30 µmol/L). The down-regulation of integrin ß4 or Fyn in VECs by the specific siRNA (20 nmol/L) was able to counteract the effects of VECs on the SPC-induced VSMC contractions. Furthermore, the integrin ß4-specific siRNA (20 and 40 nmol/L) significantly reduced the level of Fyn protein and the production of NO in VECs, while increased the level of ROCK in VSMCs that had been stimulated by SPC. CONCLUSION: The VECs reduced the SPC-induced contraction of VSMCs in the co-culture system through integrin ß4 and Fyn proteins. In this process, NO may be the factor downstream of integrin ß4 in VECs, while ROCK may be the key protein regulating the contraction of VSMCs.

Safrole oxide induces human umbilical vein endothelial cell transdifferentiation to 5-hydroxytryptaminergic neuron-like cells through tropomyosin receptor kinase A/cyclooxygenase 2/nuclear factor-kappa B/interleukin 8 signaling.

The phenomenon of endothelial-neural transdifferentiation has been observed for a long time, but the mechanism is not clear. We previously found that safrole oxide induced human umbilical vein endothelial cell transdifferentiation into neuron-like cells. In this study, we first validated that these cells induced by safrole oxide were functional 5-hydroxytryptaminergic neuron-like cells. Then, we performed microarray analysis of safrole oxide-treated and -untreated human umbilical vein endothelial cells. Safrole oxide elevated the levels of cyclooxygenase 2 (COX-2), interleukin-8 (IL-8) and reactive oxygen species (ROS), which was accompanied by nuclear factor-kappa B (NF-κB) nuclear translocation during the transdifferentiation. Blockade of tropomyosin receptor kinase A (TrkA) by an inhibitor or short hairpin RNA inhibited the levels of COX-2/IL-8 and the nuclear translocation of NF-κB but did not suppress the increased ROS level. As a result, cells underwent apoptosis. Therefore, via TrkA, safrole oxide may induce endothelial cell transdifferentiation into functional neuron-like cells. During this process, the increased levels of COX-2/IL-8 and the subsequent elevation of ROS production induced NF-κB nuclear translocation and IL-8 secretion. With the activity of TrkA inhibited, the inactive NF-κB regulated the ROS level in a negative feedback manner. Finally, the transdifferentiation pathway was blocked and cells became apoptotic. The TrkA/COX-2/IL-8 signal pathway may have an important role in endothelial-neural transdifferentiation, and safrole oxide may trigger this process by activating TrkA.

Microwave-assisted synthesis, crystal structure of pyrazolo[1,5-a]pyrazin-4(5H)-ones and their selective effects on lung cancer cells.

A series of novel pyrazolo[1,5-a]pyrazin-4(5H)-one derivatives with hydrophilic group was synthesized under general heating condition and microwave-assisted condition. The structures of compounds were determined by IR, 1H NMR and HRMS, moreover, representative crystal structures were characterized by using X-ray diffraction analysis. Preliminary biological evaluation showed that some compounds could inhibit the growth of A549, H322 and H1299 cells in dosage dependent manners. The compounds could inhibit growth of A549, H322 and H1299 cells in different mechanism. Compounds 3e-h inhibited growth of A549 cells by inducing a strong G1-phase arrest. Whereas these compounds inhibited growth of H1299 and H322 cells by inducing apoptosis.

Lipopolysaccharide activated phosphatidylcholine-specific phospholipase C and induced IL-8 and MCP-1 production in vascular endothelial cells.

Secretion of proinflammatory cytokines by lipopolysaccharide (LPS) activated vascular endothelial cells (VECs) contributes substantially to the pathogenesis of several inflammatory diseases such as atherosclerosis and septic shock. However, the mechanisms involved in this process are not well understood. Here, we investigated the role of phosphatidylcholine-specific phospholipase C (PC-PLC) in LPS-induced IL-8 and MCP-1 production in VECs. The results showed that LPS elevated the level of PC-PLC and the production of IL-8 and MCP-1 in Human umbilical vein vascular endothelial cells (HUVECs). Blocking the function of PC-PLC by exploiting the neutralization antibody of PC-PLC or tricyclodecan-9-yl-xanthogenate (D609), an inhibitor of PC-PLC, significantly inhibited LPS-induced production of IL-8 and MCP-1 in HUVECs. Furthermore, the in vivo experimental results showed that the levels of PC-PLC, IL-8, and MCP-1 in the aortic endothelium and serum were increased in mice injected with LPS. The increased levels of these molecules were also inhibited by the treatment with D609. The data suggested that blocking PC-PLC function significantly inhibited LPS-induced IL-8 and MCP-1 production in cultured HUVECs and in vivo. PC-PLC might be a potential target for therapy in inflammation associated-diseases such as atherosclerosis.

N-benzyl-5-phenyl-1H-pyrazole-3-carboxamide promotes vascular endothelial cell angiogenesis and migration in the absence of serum and FGF-2.

AIM: To investigate the effect of N-benzyl-5-phenyl-1H-pyrazole-3-carboxamide (BPC) on angiogenesis in human umbilical vein endothelial cells (HUVECs). METHODS: Capillary-like tube formation on matrigel and cell migration analyses were performed in the absence of serum and fibroblast growth factor (FGF-2). Reactive oxygen species (ROS) were measured using a fluorescent probe, 2', 7'- dichlorodihydrofluorescein (DCHF). The nitric oxide (NO) production of HUVECs was examined using a NO detection kit. Morphological observation under a phase contrast microscope, a viability assay using 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyl-tetrazolium (MTT) and a lactate dehydrogenase (LDH) activity analysis by a detection kit were performed to evaluate the toxicity of BPC on HUVECs in the presence of serum and FGF-2. The level of hypoxia-inducible factor 1α (HIF-1α) and the release of vascular endothelial growth factor (VEGF) were measured by Western blot and ELISA, respectively. RESULTS: In the absence of serum and FGF-2, cells treated with BPC (5-20 µmol/L) rapidly aligned with one another and formed tube-like structures within 12 h. In the presence of serum and FGF-2, cells treated with BPC for 24, 48 and 72 h had no changes in morphology, viability or LDH release compared with the control group. Cell migration in the BPC-treated group was significantly increased compared with the control group. During this process, NO production and ROS level were elevated dramatically, and the levels of HIF-1α and VEGF were increased dependent on the generation of ROS. CONCLUSION: BPC most effectively promoted angiogenesis and migration in HUVECs in the absence of FGF-2 and serum.

5-Alkyl-2-ferrocenyl-6,7-dihydropyrazolo[1,5-a]pyrazin-4(5H)-one derivatives inhibit growth of lung cancer A549 cell by inducing apoptosis.

we found that 5-alkyl-2-ferrocenyl-6,7-dihydropyrazolo[1,5-a]pyrazin-4(5H)-one derivatives 8d, 8e and 8f could effectively induce apoptosis in A549 lung cancer cells and elevate the levels of integrin beta4 and ROS. The data suggested that these compounds might be promising agents for the cancer therapy, and these compounds would be useful tools for further investigate the functions of integrin beta4 in regulation of the cancer cell apoptosis.

Synthesis and discovery of a novel pyrazole derivative as an inhibitor of apoptosis through modulating integrin beta4, ROS, and p53 levels in vascular endothelial cells.

Recently, pyrazole derivatives as high affinity and selective A2A adenosine receptor antagonists have been reported. But, so far, there are no reports about the inhibitory effects of multi-substituted pyrazole derivatives on apoptosis of vascular endothelial cells (VECs). In this study, we synthesized six pyrazole derivatives and characterized the structures of the compounds by IR, (1)H NMR, mass spectroscopy, and element analysis. The biology assay showed that a novel pyrazole derivative, ethyl 3-(o-chlorophenyl)-5-methyl-1-phenyl-1H-pyrazole-4-carboxylate (MPD) at low concentration (25muM) increased VECs viability and inhibited VECs apoptosis induced by deprivation of serum and FGF-2. During this process, the levels of integrin beta4, reactive oxygen species (ROS), and p53 were depressed obviously. The data suggested that MPD was a potential inhibitor of apoptosis associated with the signal pathway mediated by integrin beta4, ROS, and p53 in VECs.

Heterologous expression of vacuolar H(+)-PPase enhances the electrochemical gradient across the vacuolar membrane and improves tobacco cell salt tolerance.

The vacuolar H(+)-translocating inorganic pyrophosphatase (H(+)-PPase) uses pyrophosphate as substrate to generate the proton electrochemical gradient across the vacuolar membrane to acidify vacuoles in plant cells. The heterologous expression of H(+)-PPase genes (TsVP from Thellungiella halophila and AVP1 from Arabidopsis thaliana) improved the salt tolerance of tobacco plants. Under salt stress, the transgenic seedlings showed much better growth and greater fresh weight than wild-type plants, and their protoplasts had a normal appearance and greater vigor. The cytoplasmic and vacuolar pH in transgenic and wild-type cells were measured with a pH-sensitive fluorescence indicator. The results showed that heterologous expression of H(+)-PPase produced an enhanced proton electrochemical gradient across the vacuolar membrane, which accelerated the sequestration of sodium ions into the vacuole. More Na(+) accumulated in the vacuoles of transgenic cells under salt (NaCl) stress, revealed by staining with the fluorescent indicator Sodium Green. It was concluded that the tonoplast-resident H(+)-PPase plays important roles in the maintenance of the proton gradient across the vacuolar membrane and the compartmentation of Na(+) within vacuoles, and heterologous expression of this protein enhanced the electrochemical gradient across the vacuolar membrane, thereby improving the salt tolerance of tobacco cells.

Safrole oxide induced human umbilical vein vascular endothelial cell differentiation into neuron-like cells by depressing the reactive oxygen species level at the low concentration.

Previously, we found that 5-25 microg/ml safrole oxide could inhibit apoptosis and dramatically make a morphological change in human umbilical vein vascular endothelial cells (HUVECs). But the possible mechanism by which safrole oxide function is unknown. To answer this question, in this study, we first investigated the effects of it on the activity of nitric oxide synthetase (NOS), the expressions of Fas and integrin beta4, which play important roles in HUVEC growth and apoptosis, respectively. The results showed that, at the low concentration (10 microg/ml), safrole oxide had no effects on NOS activity and the expressions of Fas and integrin beta4. Then, we investigated whether HUVECs underwent differentiation. We examined the expressions of neuron-specific enolase (NSE) and neurofilament-L (NF-L). Furthermore, we analyzed the changes of intracellular reactive oxygen species (ROS). After 10 h of treatment with 10 microg/ml safrole oxide, some HUVECs became neuron-like cells in morphology, and intensively displayed positive NSE and NF-L. Simultaneously, ROS levels dramatically decreased during HUVECs differentiation towards neuron-like cells. At the low concentration, safrole oxide induced HUVECs differentiation into neuron-like cells. Furthermore, our data suggested that safrole oxide might perform this function by depressing intracellular ROS levels instead of by affecting cell growth or apoptosis signal pathways.

Discovery of a novel small molecule, 1-ethoxy-3-(3,4-methylenedioxyphenyl)-2-propanol, that induces apoptosis in A549 human lung cancer cells.

A novel small molecule, 1-ethoxy-3-(3,4-methylenedioxyphenyl)-2-propanol (EOD), was synthesized in our laboratory. Previously, we reported pharmacological properties of EOD, triggering apoptosis in Human umbilical vein endothelial cells (HUVECs). Here, we further investigated the effects of EOD on the growth of A549 human lung cancer cells. EOD treatment induced apoptosis in A549 cells via up-regulating the expression of P53 protein, blocking cell cycle partly at G1 phase, and ultimately activating caspase-3. In contrast, caspase-8 might be irrelevant to EOD-triggered apoptosis. This study indicated that EOD might be a potential chemopreventive agent for lung cancer. The work would encourage us to add more novel compounds to our 'library' of small molecules derived through modern synthetic organic chemistry, and would drive us to determine the proteins that the compounds target.

Integrin beta4 mAb inhibited apoptosis induced by deprivation of growth factors in vascular endothelial cells.

AIM: To understand the mechanism by which anti-beta4 integrin monoclonal antibody (mAb) inhibits apoptosis of vascular endothelial cells (VEC). METHODS: Viability was determined by counting the cells that attached to dishes after treatments. DNA fragmentation was analyzed by agarose gel electrophoresis and fluorescence microscopy. The intracellular content of cAMP was measured by radioimmunoassay (RIA). The levels of p53 and Ras expressions were analyzed by fluorescence microscopy combined with immunofluorescence under laser scanning confocal microscopy. RESULTS: After the cells were deprived of fibroblast growth factor (FGF) and serum were exposed to the mAb 5 mg/L for 24 h, the detachment and DNA fragmentation of these cells were suppressed. When cells were deprived of FGF and serum, the intracellular cAMP level and Ras protein content decreased (P<0.05), while the level of p53 protein expression increased (P<0.05). But in the presence of anti-beta4 integrin mAb, VEC apoptosis was inhibited, and at the same time, the changes mentioned above were obviously blocked (P<0.05). CONCLUSION: Anti-4 integrin mAb inhibited apoptosis by affecting the level of cAMP, and blocking down-regulation of Ras protein and up-regulation of p53 protein in VEC.

D609 induces vascular endothelial cells and marrow stromal cells differentiation into neuron-like cells.

AIM: To investigate the effect of tricyclodecane-9-yl-xanthogenate (D609) on cell differentiation in vascular endothelial cells (VECs) and marrow stromal cells (MSCs). METHODS: Morphological changes were observed under phase contrast microscope. Electron microscope and immunostaining were used for VECs identification. The expressions of neuron-specific enolase (NSE) and glial fibrillary acidic protein (GFAP) were examined by immunohistochemistry. RESULTS: After 6 h of induction with D609, some VECs showed morphological changes characteristic of neurones. 9 h later, more VECs became neuron-like cells. About 30.8% of VECs displayed positive NSE (P<0.01), while the expression of GFAP was negative. When MSCs were exposed to D609, the cells displayed neuronal morphologies, such as pyramidal cell bodies and processes formed extensive networks at 3 h. 6 h later, almost all of the cells exhibited a typical neuronal appearance, and 85.6% of MSCs displayed intensive positive NSE, but GFAP did not express. CONCLUSION: D609 induces VECs and MSCs differentiation into neuron-like cells.

Effect of safrole oxide on vascular endothelial cell growth and apoptosis induced by deprivation of fibroblast growth factor.

AIM: To investigate effect of safrole oxide on cell growth and apoptosis induced by deprivation of survival factors (fibroblast growth factors, aFGF and bFGF) in vascular endothelial cells (VEC). METHODS: Morphological changes were observed by light microscopy. Cell growth was determined by MTT (3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium) method. DNA fragmentation was analyzed by agarose gel electrophoresis and fluorescence microscopy. Cell cycle distribution was analyzed by flow cytometry (FCM). RESULTS: The cells deprived of FGF were exposed to safrole oxide 5-25 mg/L for 24 h. Cells spreading and growth were promoted (P<0.01), detachment and DNA fragmentation of these cells were suppressed (P<0.01), safrole oxide 10 mg/L had no obvious effect on cell cycle distribution (P>0.05). When the cells were treated with safrole oxide 50-100 mg/L, detachment and DNA fragmentation of VEC were promoted (P<0.01). The cell cycle was blocked at G2-M phase by safrole oxide 100 mg/L. CONCLUSION: Safrole oxide 10 mg/L inhibited, but 100 mg/L promoted apoptosis of VEC. Safrole oxide might be an important compound that affects VEC growth and apoptosis.