Oridonin induces NPM mutant protein translocation and apoptosis in NPM1c＋ acute myeloid leukemia cells in vitro

Aim： Skewed cytoplasmic accumulation of NPM mutant protein （NPM1c＋） is close related to leukemia pathogenesis. The aim of this study was to investigate whether oridonin, a diterpenoid isolated from the Chinese traditional medicine Rabdosia rubescens, was able to interfere with NPM1c＋ protein trafficking and induce apoptosis in NPM1c＋ acute myeloid leukemia cells in vitro.
Methods： OCI-AML3 cell line harboring a NPM1 gene mutation was examined. Cell growth was detected by MTT assay. Cell apoptosis was evaluated using flow cytometry and Hoechst 33258 staining. The expression and subcellular localization of relevant proteins were detected by Western blot and immunofluorescent staining. The mRNA expression was detected by RT-PCR.
Results： Oridonin （2–12 μmol/L） dose-dependently inhibited the viability of OCI-AML3 cells （the IC50 value was 3.27±0.23 μmol/L at 24 h）. Moreover, oridonin induced OCI-AML3 cell apoptosis accompanied by activation of caspase-3 and nuclear translocation of NPM1c＋ protein. Oridonin did not change the expression of Crm1 （the export receptor for nuclear export signal-containing proteins）, but induced nuclear translocation of Crm1. Oridonin markedly increased the expression of nucleoporin98 （Nup98）, which had an important role in Crm1-mediated nuclear protein export, and induced nuclear accumulation of Nup98. Furthermore, oridonin markedly increased the expression of p14arf and p53.
Conclusion： In NPM1c＋ leukemia cells, oridonin induces NPM1c＋ protein translocation into the nucleus possibly via nuclear accumulation of Crm1; the compound markedly increases p53 and p14arf expression, which may contribute to cell apoptosis.     

The antiproliferative effects of somatostatin receptor subtype 2 in breast cancer cells

Aim： Somatostatin receptor subtype 2 （SSTR2） is the principal mediator of somatostatin＇s （SST） antiproliferative effects on normal and cancer cells. Therefore, we investigated whether the enhanced expression of SSTR2 could inhibit the proliferation of tumor cells, and, if so, the mechanisms that might be involved.
Methods： SSTR2 expression levels were determined by qRToPCR in several tumor cell lines. Then, a plasmid plRES2-EGFP-SSTR2 （pSlG） was constructed and stably transfected into MCF-7 cells （MCF-7/pSIG）. After SSTR2 overexpression was identified by qRT-PCR, immunofluorescence staining and a receptor binding assay, the MCF-7/pSIG cells were analyzed by PI staining for apoptosis and cell cycle arrest was tested by flow cytometry for epidermal growth factor receptor （EGFR） expression. The EGF-stimulated proliferation of MCF-7 cells was assayed by MTT.
Results： The human breast cancer cell line MCF-7 expresses a lower level of SSTR2, thereby partly accounting for the decreased response to SST. The overexpression of SSTR2 in MCF-7 cells resulted in apoptosis, cytostasis and G1/S cell cycle arrest. Furthermore the expression of EGFR, together with EGF-stimulated proliferation, was markedly decreased in the MCF-7/pSlG cells.
Conclusion： Enhanced SSTR2 expression played an antiproliferative role in MCF-7 cells through inducing apoptosis and G1/S cell cycle arrest, and also by decreasing EGFR expression, thereby counteracting the growth-stimulating effect of EGF. Our data seem to indicate that developing a new therapeutic agent capable of upregulating SSTR expression could potentially be a way to block tumor progression.     

Calcineurin-NFAT signaling is involved in phenylephrine-induced vascular smooth muscle cell proliferation

Aim： Catecholamine-induced vascular smooth muscle cell （VSMC） proliferation is one of the major events in the pathogenesis of atherosclerosis and vascular remodeling. The calcineurin-NFAT pathway plays a role in regulating growth and differentiation in various cell types. We investigated whether the calcineurin-NFAT pathway was involved in the regulation of phenylephrine-induced VSMC proliferation. Methods： Proliferation of VSMC was measured using an MTT assay and cell counts. Localization of NFATcl was detected by immunofluorescence staining. NFATcl-DNA binding was determined by EMSA and luciferase activity analyses. NFATcl and calcineurin levels were assayed by immunoprecipitation. Results： Phenylephrine （PE, an α1-adrenoceptor agonist） increased VSMC proliferation and cell number. Prazosin （an α1-adrenoceptor antagonist）, cyclosporin A （CsA, an inhibitor of calcineurin） and chelerythrine （an inhibitor of PKC） decreased PE-induced proliferation and cell number. Additional treatment of VSMC with CsA or chelerythrine further inhibited proliferation and cell number in the chelerythrine-pretreatment group and the CsA-pretreatment group. CsA and chelerythrine alone had no effect on either absorbance or cell number. CsA decreased PE-induced calcineurin levels and activity. NFATcl was translocated from the cytoplasm to the nucleus upon treatment with PE. This translocation was reversed by CsA. CsA decreased the PE-induced NFATcl level in the nucleus. PE increased NFAT＇s DNA binding activity and NFAT-dependent reporter gene expression. CsA blocked these effects. Conclusion： CsA partially suppresses PE-induced VSMC proliferation by inhibiting calcineurin activity and NFATcl nuclear translocation. The calcineurin-NFATcl pathway is involved in the hyperplastic growth of VSMC induced by phenylephrine.     

Anticancer effect of aloe-emodin on cervical cancer cells involves G2/M arrest and induction of differentiation

Aim： The aim of this study was to investigate the effects of aloe-emodin, a natural compound from the root and rhizome of Rheum palmatum, on the growth of hu- man cervical cancer cells, HeLa. Methods： HeLa cells were treated with various concentrations of aloe-emodin for 1-5 d, and cell growth was measured by 3-（4, 5- dimethylthiazol-2-yl）-2, 5-diphenyl tetrazolium bromide assay. The long-term growth effect was investigated by crystal violet assay. The distributions of the cell cycle and apoptosis were analyzed by flow cytometry. The alkaline phos- phatase （ALP） activity was analyzed by a chemical analyzer. Finally, Western blotting was used to indicate the abundant changes of protein kinase C （PKC）, c- myc, cyclins, cyclin-dependent kinases （CDK）, and proliferating cell nuclear anti- gen （PCNA）. Results： Aloe-emodin inhibited the growth of HeLa cells in a dose- dependent manner at concentrations ranging between 2.5 and 40 0rnol/L. The flow cytometric analysis showed that HeLa cells were arrested at the G2/M phase. This effect was associated with the decrease in cyclin A and CDK2, and the increase in cyclin B 1 and CDK1. More importantly, the ALP activity was found to be increased by aloe-emodin treatment, and accompanied by the inhibition of PCNA expression. In addition, aloe-emodin suppressed the expression of PKCα and c-myc. Conclusion： These findings provide a possible mechanistic explana- tion for the growth inhibitory effect of aloe-emodin on HeLa, which includes cell cycle arrest and inducing differentiation.     

Inhibition of epidermal growth factor receptor expression by RNA interference in A549 cells

AIM: To investigate the biological features of A549 cells in which epidermal growth factor (EGF) receptors expression were suppressed by RNA interference (RNAi). METHODS: A549 cells were transfected using short small interfering RNAs (siRNAs) formulated with Lipofectamine 2000. The EGF receptor numbers were determined by Western blotting and flowcytometry. The antiproliferative effects of sequence specific double stranded RNA (dsRNA) were assessed using cell count, colony assay and scratch assay. The chemosensitivity of transfected cells to cisplatin was measured by MTT. RESULTS: Sequence specific dsRNA-EGFR down-regulated EGF receptor expression dramatically. Compared with the control group, dsRNA-EGFR reduced the cell number by 85.0 %, decreased the colonies by 63.3 %, inhibited the migration by 87.2 %, and increased the sensitivity of A549 to     

Biological characterization of a novel and potent gonadotropin releasing hormone （GnRH） antagonist LXT-101

AIM The biological characterization of LXT-101 was investigated in vivo using intact male rats and nude mice bearing xenografts of LNCaP prostate cancer. The effect of LXT-101 on the proliferation of androgen -sensitive prostate cancer cell LNCaP and androgen-insensitive DU145 and PC-3M in vitro was also determined. METHODS Rats were injected subcutaneously with LXT-101 while control animals received only vehicle (5% mannitol). Blood samples were collected at different time after adminis-tration of LXT-101. The androgen-dependent LNCaP prostate cancer cells were grown, mixed with Matrigel and injected subcutaneously into nude mice. Experimental group received LXT-101 injectionfor up to 4 weeks. At the end point, blood samples were drawn and the excised tumors and sex organswere weighted. The serum testosterone was determined by specific immunochemiluminescence assay using kits produced by Beckman-Counter Co. The mRNA expressions of the genes of hormone receptor related to the gonadal axis were investigated by real-time RT-PCR technique. Cell viability was determined by MTT method.     

Overexpression of coxsackie and adenovirus receptor inhibit growth of human bladder cancer cell in vitro and in vivo

Aim： To study the effect of the overexpression of coxsackie and the adenovirus receptor （CAR） on the growth of the human bladder cancer cell in vitro and in vivo. Methods： A retroviral vector pLXSN-CAR expressing CAR was constructed and confirmed by restriction enzyme mapping. The pLXSN-CAR vector and con- trol vector pLXSN were transfected into the PT67 packaging cell line to generate retrovirus with high titer. The CAR-negative T24 cell was infected with the pLXSNCAR and the pLXSN retrovirus, respectively. The positive clone cells were selected with G418 for 2 weeks. The expression level of the CAR protein was detected by Western blot assay. T24 cell growth in vitro was determined by 3-（4, 5-dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide （MTT） assay. Anchorage-independent growth was measured by soft-agar colony formation assay. In vivo cell growth was determined by a nude mice xenograft model. Results： The pLXSN-CAR vector containing full-length CAR cDNA was successfully constructed. Western blot analysis showed that a 46 kDa specific band was found in pLXSN-CA-transfected T24 cells. MTT assay identified the growth inhibition of T24/pLXSN-CAR cells. The cell colony forming ability of T24/pLXSNCAR cells was significantly lower than that of T24/pLXSN and parental T24 cells. There was a reduction in the tumor size in the T24/pLXSN-CAR group as compared with that of the T24/pLXSN group and parental T24 group. Conclusion： The overexpression of CAR in T24 bladder cancer cells can inhibit cell growth both in vitro and in vivo.     

Effect of α-pinene on nuclear translocation of NF-κB in THP-1 cells

AIM: To study the effects of α-pinene on nuclear translocation of nuclear factor-κB (NF-κB) and the expression of the inhibitor of NF-κB (IκBα) in human monocyte THP-1 cell line. METHODS: THP-1 cells were incubated with α-pinene (1, 10, and 100 mg/L, for 30 min) before being stimulated with lipopolysaccharide (LPS, 1 mg/L, 30 min).The location of NF-κB p65 subunit (NF-κB/p65) in THP-1 cells was detected by immunofluorescence and laser scanning confocal microscope (LSCM). The expression of NF-κB/p65 in nuclei and that of IκBα in cytoplasm were measured by Western-blot analysis. RESULTS: The majority of FITC-labelled NF-κB/p65 was located in the nuclei being stimulated with LPS. Whereas, no such fluorescence was seen in the nuclei of the groups pretreated with α-pinene or control cells, α-Pinene pretreatment decreased the NF-κB/p65 nuclear translocation in LPS-stimulated THP-1 cells, and this effect was dose-dependent, but there was no reaction in LPS-unstimulated THP-1 cells, α-Pinene pretreatment increased IκBα protein level in cytoplasm, compared with that in LPS-stimulated THP-1 cells. CONCLUSION: In a dose-related fashion, α-pinene inhibits the nuclear translocation of NF-κB induced by LPS in THP- 1 cells, and this effect is partly due to the upregulation of IκBα expression.     

Trafficking of α1B-adrenergic receptor mediated by inverse agonist in living cells

AIM The project is aimed at understanding the action of inverse agonist at single molecule level and capturing the real time picture of molecular behavior of α1B-adrenergic receptor (AR) mediated by inverse agonist in living cells by single molecule detection (SMD). METHODS The location and distribution of α1B-AR was detected by laser confocal and whole cell ^3H-prazosin binding assay. Dynamic imaging of BODIPY-FL-labeled prazosin (Praz), specific antagonist of (1-AR, was observed in α1B-AR stably expressed human embryonic kidney 293 (HEK293) living cells. The detection of real-time dynamic behaviors of AR was achieved by using fluorescence-labeled AR and its ligand combined with SMD techniques. RESULTS α1B-AR was predominantly distributed on the cell surface and 8.2% of the total receptors were located in cytosol.     

Polypeptide from Chlamys farreri attenuates murine thymocytes damage induced by ultraviolet B

Aim： Polypeptide from Chlamysfarreri （PCF, molecular mass is 879） is a new marine polypeptide compound isolated from Chlamysfarreri. This study investigates the possible protective roles and the mechanism of PCF against ultraviolet B （UVB）-induced apoptosis in murine thymocytes. Methods： The rate of apoptosis and caspase-3 activation was measured by flow cytometry. The expression of stress-response genes c-fos and c-jun was observed by RT-PCR. Western blot analysis was performed to determine the release of cytochrome c. Results： It was found that UVB induced murine thymocyte death. The cells treated with UVB showed an increase in cytochrome c release, caspase-3 activity, as well as in the expression of c-fos and c-jun. In addition, all were involved in UVB-induced cell apoptosis. Conclusion： Our present observations pointed to the ability of PCF to avert UVB-induced apoptosis in thymocytes by modulating c-fos and c-jun expression, cytochrome c release, and the consequent activation of caspase-3, which were essential components of the UV-induced cell apoptotic pathway. The results suggested that PCF is a promising protective substance against UV radiation.     

Effect of angiotensin Ⅱ type 1 receptor on delayed rectifier potassium current in catecholaminergic CATH.a cells

AIM: To study the modulatory effects of angiotensin Ⅱ (Ang Ⅱ) on the delayed rectifier potassium (Kv) current (IKv) and its underlying intracellular mechanism in the catecholaminergic system of rats. METHODS: AT1 and AT2 receptors of the differentiated and undifferentiated CATH.a cells were determined by radioligands binding assay. The IKv was recorded with the whole cell patch-clamp configuration in voltage clamp mode on CATH.a cells. RESULTS: The Ang Ⅱ receptor proteins including AT1 and AT2 receptors were expressed in CATH.a cells, and the number of the former was significantly more than the latter (P<0.01). The IKv of CATH.a cells was reduced by superfusion with the Ang Ⅱ (100 nmol/L) (P<0.05) in the presence of the AT2 receptor antagonist PD123319, but was not affected by only superfusion with PD123319. The effect of Ang Ⅱ on IKv in CATH.a cells was completely inhibited by addition of AT1 receptor antagonist losartan. Superfusion with Ang Ⅱ (100 nmol/L) plus U73122, an inhibitor of     

A novel PPAR alpha／gamma dual agonist inhibits cell growth and induces apoptosis in human glioblastoma T98G cells

AIM: To examine the effect of a novel peroxisome proliferator-activated receptor (PPAR) α/γ dual agonist TZD 18 on cell proliferation and apoptosis in human glioblastoma T98G cells and its possible mechanism. METHODS: RTPCR, MTT, TUNEL, Flow cytometry, and Western blot analysis were employed. RESULTS: TZD18 inhibited the growth of T98G cells in a concentration-dependent manner, which was associated with a GI to S cell cycle arrest. Besides, significant apoptosis was induced after treatment with a non-toxic dose of TZD 18. During the process, the expression of Bcl-2 protein was down-regulated, while that of Bax and p27^kip proteins was up-regulated, and the activity of caspase-3 was elevated. However, this effect appeared to be PPARα and PPARγ/independent since their antagonists could not reverse this effect. CONCLUSIONS: TZD18, a novel PPARα/γ dual agonist, inhibited cell growth and induce apoptosis in human glioblastoma T98G cells in vitro, indicating a therapeutic potential for TZD18 in the treatment of glioblastoma.     

Ric-3 chaperone-mediated stable cell-surface expression of the neuronal α7 nicotinic acetylcholine receptor in mammalian cells

Aim： Studies of the α7-type neuronal nicotinic acetylcholine receptor （AChR）, one of the receptor forms involved in many physiologically relevant processes in the central nervous system, have been hampered by the inability of this homomeric protein to assemble in most heterologous expression systems. In a recent study, it was shown that the chaperone Ric-3 is necessary for the maturation and functional expression of α7-type AChRs. The current work aims at obtaining and characterizing a cell line with high functional expression of the human α7 AChR. Methods： Ric-3 cDNA was incorporated into SHE-P1-hα7 cells expressing the α7-type AChR. Functional studies were undertaken using single-channel patch-clamp recordings. Equilibrium and kinetic [125Ⅰ]α-bungarotoxin binding assays, as well as fluorescence microscopy using fluorescent α-bungarotoxin, anti-α7 antibody, and GFP-α7 were performed on the new clone. Results： The human α7-type AChR was stably expressed in a new cell line, which we coined SHE-P1-hα7-Ric-3, by co-expression of the chaperone Ric-3. Cell-surface AChRs exhibited [125Ⅰ]aBTX saturable binding with an apparent KD of about 55 nmol/L. Fluorescence microscopy revealed dispersed and micro-clustered AChR aggregates at the surface of SHE-PI-hα7- Ric-3 cells. Larger micron-sized clusters were observed in the absence of receptor-clustering proteins or upon aggregation with anti-α7 antibodies. In contrast, chaperone-less SHE-PI-hα7 cells expressed only intracellular α7 AChRs and failed to produce detectable single-channel currents. Conclusion： The production of a stable and functional cell line of neuroepithelial lineage with robust cell-surface expression of neuronal α7-type AChR, as reported here, constitutes an important advance in the study of homomeric receptors in mammalian cells.     

Oxidative modulation of marcaine and lekoptin in H9C2 rat myoblasts

Aim： The cytotoxicity of marcaine was estimated in combination with a calcium channel blocker. In addition, the influence of marcaine and marcaine plus lekoptin on a model system using the H9C2 cardiac cell line was investigated. Methods： Cells were incubated for five hours with marcaine, lekoptin, or with both drugs simultaneously. Apoptotic cells were detected using the TUNEL assay and the alkaline comet assay. Mitochondrial cell function after drug uptake was examined using the MTT assay. The concentration of MDA （malondialdehyde） - the final product of fatty-acid peroxidation, was quantified spectrophotometrically. The expression of glutathione S-transferase n （GST-rI） was detected by immunofluorescence （IF） and Western blotting （WB） and inducible nitric oxide synthase （iNOS） was assessed by immuno-cytochemical staining （ABC）. Results： Incubation with marcaine resulted in the highest number of apoptotic cells. After incubation with both marcaine and lekoptin, moderate damage to cells （54.2%＋1.775% of DNA destruction） was observed. The highest levels of iNOS and GST-n expression were observed in cells treated with marcaine and marcaine plus lekoptin. The characteristic nuclear GST-n expression was observed in cells treated with both drugs. Conclusion： Lekoptin stimulated cells to proliferate. Marcaine caused membrane damage and ultimately cell death.     

Genipin inhibits endothelial exocytosis via nitric oxide in cultured human umbilical vein endothelial cells

Aim： Exocytosis of endothelial Weibel-Palade bodies, which contain von Willebrand factor （VWF）, P-selectin and other modulators, plays an important role in both inflammation and thrombosis. The present study investigates whether genipin, an aglycon of geniposide, inhibits endothelial exocytosis. Methods： Human umbilical vein endothelial cells （HUVECs） were isolated from umbilical cords and cultured. The concentration of VWF in cell supernatants was measured using an ELISA Kit. P-selectin translocation on the cell surface was analyzed by cell surface ELISA. Cell viability was measured using a Cell Counting Kit-8. Mouse bleeding times were measured by amputating the tail tip. Western blot analysis was used to determine the amount of endothelial nitric oxide synthase （eNOS） and phospho-eNOS present. Nitric oxide （NO） was measured in the cell supernatants as nitrite using an NO Colorimetric Assay. Results： Genipin inhibited thrombin-induced VWF release and P-selectin translocation in HUVECs in a dose- and time- dependent manner. The drug had no cytotoxic effect on the cells at the same doses that were able to inhibit exocytosis. The functional study that demonstrated that genipin inhibited exocytosis in vivo also showed that genipin prolonged the mouse bleeding time. Furthermore, genipin activated eNOS phosphorylation, promoted enzyme activation and increased NO production. L-NAME, an inhibitor of NOS, reversed the inhibitory effects of genipin on endothelial exocytosis. Conclusion： Genipin inhibits endothelial exocytosis in HUVECs. The mechanism by which this compound inhibits exocytosis may be related to its ability to stimulate eNOS activation and NO production. Our findings suggest a novel antiinflammatory mechanism for genipin. This compound may represent a new treatment for inflammation and/or thrombosis in which excess endothelial exocytosis plays a pathophysiological role.     

Dihydroartemisinin is an inhibitor of ovarian cancer cell growth

Aim： To investigate the anticancer activity of dihydroartemisinin （DHA）, a derivative of antimalaria drug artemisinin in a panel of human ovarian cancer cell lines. Methods： Cell growth was determined by the MTT viability assay. Apoptosis and cell cycle progression were evaluated by a DNA fragmentation gel electro-phoresis, flow cytometry assay, and TUNEL assay; protein and mRNA expression were analyzed by Western blotting and RT-PCR assay. Results： Artemisinin and its derivatives, including artesunate, arteether, artemether, arteannuin, and DHA, exhibit anticancer growth activities in human ovarian cancer cells. Among them, DHA is the most effective in inhibiting cell growth. Ovarian cancer cell lines are more sensitive （5-10-fold） to DHA treatment compared to normal ovarian cell lines. DHA at micromolar dose levels exhibits a dose- and time-dependent cytotoxicity in ovarian cancer cell lines. Furthermore, DHA induced apoptosis and G2 cell cycle arrest, accompanied by a decrease of Bcl-XL and Bcl-2 and an increase of Bax and Bad. Conclusion： The promising results show for the first time that DHA inhibits the growth of human ovarian cancer cells. The selective inhibition of ovarian cancer cell growth, apoptosis induction, and G2 arrest provide in vitro evidence for further studies of DHA as a possible anticancer drug in the clinical treatment of ovarian cancer.