Antineoplastic mechanism of Octreotide actionin human hepatoma

Objectives To investigate whether apoptosis can be induced by Octreotide in human hepatoma cells in vitro and elucidate the antineoplastic mechanism of Octreotide in hepat oma. Methods A cultured human hepatoma cell line, BEL-7402, was exposed to Octreotide and ap optosis was evaluated by cytochemical staining (Hochesst 33 258), transmiss ion electron microscopy, agarose gel electrophoresis and flow cytometry (FCM).Results After exposure to 0.2 μg/ml Octreotide, apoptosis with nuclear chromatin cond ensation as well as fragmentation, cell shrinkage and the formation of apoptotic bodies was observed using cytochemical staining and transmission electron micros copy. A DNA ladder in agarose gel electrophoresis was also displayed. FCM show ed that the apoptotic cell number rose with an increase in the concentration of Octreotide (0-2 μg/ml). There was a positive correlation between Octreotide concentration and apoptotic rate in BEL-7402 cells (r=0.809, P<0.05) .Conclusion Apoptosis in human hepatoma cells can be induced by Octreotide, which may be rel ated to the mechanism of antineoplastic action ofOctreotide in hepatoma.     

Effect of lidamycin on telomerase activity in human hepatoma BEL-7402 cells

Objective To investigate the effect of lidamycin (LDM) on telomerase activity in human hepatoma BEL-7402 cells under the condition of LDM inducing mitotic cell death and senescence. Methods Chromatin condensation was detected by co-staining with Hoechst 33342 and PI. Cell multinucleation was observed by Giemsa staining and genomic DNA was separated by agarose gel electrophoresis. Fluorescent intensity of Rho123 was determined for mitochondrial membrane potential. MTT assay and SA-β-gal staining were employed to analyze the senescence-like phenotype. The expression of proteins was analyzed by Western blot. Telomerase activity was assayed by telomerase PCR-ELISA. Results Mitotic cell death occurred in LDM-treated cells characterized by unique and atypical chromatin condensation, multinucleation and increased mitochondrial membrane potential. However, no apoptotic bodies or DNA ladders were found. In addition, apoptosis-related proteins remained nearly unaltered. Senescence-like phenotype was identified by increased and elongated size of cells, growth retardation, enhanced SA-β-gal activity and the changes of senescence-related protein expression. Telomerase activity markedly decreased (P<0.01) in LDM-treated hepatoma BEL-7402 cells. Conclusion Mitotic cell death and senescence could be triggered simultaneously or sequentially after exposure of hepatoma BEL-7402 cells to LDM. The decrease in telomerase activity may play a key role in the defective mitosis and aging morphology. Further investigation of detailed mechanism is needed.     

Effect of NS398 on inducing apoptosis and down-regulating Bcl-2 protein in human osteosarcoma cell MG-63 line

Objective： This study investigated the effect of NS398 on anti-proliferation and the mechanism of inducing apoptosis of human osteosarcoma cell MG-63 line in vitro. Methods： Growth suppression was detected by MTT method. Special morphological changes of apoptosis were observed by transmission electron microscopy （TEM） and DNA fragments electrophoresis. The apoptotic rates were quantified by flow cytometry （FCM）. And Bcl-2 protein level were detected by Western Blotting assay. Results： Different concentration NS398 inhibited the cell growth. Through TEM and DNA electrophoresis, the special morphological changes were observed after 24, 48 and 72 h treatment with NS398. The apoptotic rates of MG-63 cells treated with NS398 were respectively, significantly higher than that of the control group（ P 〈0.01 ）. Western blot assay showed that NS398 reduced Bcl-2 protein expression. Conclusion： NS398 suppressed the proliferation of human osteosarcoma cell MG-63 line and induced apoptosis. The mechanism may be associated with down-regulation expression level of bcl-2 protein.     

Study on Taxol in Inhibiting Human Leukemia Cell Proliferation andInducing Apoptosis

Objective: To explore the effects of Taxol in inhibiting human leukemia k562 cell proliferation and inducing apoptosis in vitro. Methods: Human leukemia K562 cells were treated with Taxol of different concentrations for 12-72 hrs. Cell proliferation was evaluated by MTT assay and morphological changes of apoptosis were examined by microscopy. Cell apoptosis was determined by flow cytometry (FCM) and DNA gel electrophoresis. Results: Growth of K562 cells was inhibited by Taxol with an IC50 value of 0. 84μg/ml. Typical nuclear condensation and apoptosis bodies were observed as early as 24 hrs after a 0.5μg/ml Taxol treatment; Apoptotic rate of the Taxol-treated K562 cells increased from 3.7% to 24.0% in 24 hrs. No DNA ladder was observed by DNA gel electrophoresis. Conclusion: Taxol could inhibit K562 cell growth and induce apoptosis in vitro.     

In vitro study on the morphology of human blood dendritic cells and LPAK cells inducing apoptosis of the hepatoma cell line

Objective To observe in vitro effects and morphological changes of human peripheral blood dendritic cells (DCs) on the ability of lymphokine and phytohaemagglutinin um (PHA) activated killer (LPAK) cells to induce apoptosis of the human hepa toma cell line (BEL-7402, B).Methods Experimental groups were divided into LD group （DCs+L+B）, L gro up （L+B）, D group （DCs+B） and B group. The methods of neutral red u ptake, ordinary light microscopy, electron microscopy, TDT mediated X-dUTP nick end labeling (TUNEL) were used.Results The difference between the D group and the B group was not distinct (P&gt;0.05 ). The difference between the LD group and the L group was distinct, with DCs+ LPAK &gt;LPAK (P&lt;0.01) in cytotoxity. Apoptotic cells were TUNEL positive in light microscopy, and apoptotic nuclei were stained yellow brown and dar k brown, with size and shape varying from cell to cell. Ultrastructural cha nge in apoptotic tumor cells comprised of compaction and condensation of nuclear chromatin, and condensation of cytoplasm and apoptotic bodies. At the sam e time, LPAK cells manifested the characteristics of autophagic apoptosis, and t here were some autophagic bodies in it. Conclusions The combination of human blood DCs and LPAK cells could induce apoptosis of BEL -7402 cells effectively, with some LPAK cells manifesting the characteristics o f autophagic apoptosis.     

RASSF1A expression inhibits cell growth and enhances cell chemosensitivity to mitomycin in BEL-7402 hepatocellular carcinoma cells

Background The antitumor role of Ras association domain family 1A （RASSF1A） gene and its potential molecular mechanisms are not well understood. The objective of this study was to observe the antitumor ability of RASSF1A in hepatocellular carcinoma, and study the mechanisms of cell apoptosis induced by RASSF1A. Methods After stably transfecting a RASSFIA （wild-type or mutant） expression vector into the BEL-7402 hepatocellular carcinoma cell line, RT-PCR and Western blotting was used to detect the RASSF1A expression levels in recombinant cells. The effects of wild-type RASSF1A on cell growth were observed in vitro by analyzing cell proliferation rate, cell colony formation, and in vivo by analyzing tumorigenesis in nude mice. In addition, the effect of RASSF1A gene expression on the chemosensitivity of human hepatocellular carcinoma cells to antitumor drugs was examined by inhibition of cell proliferation and the percentage of apoptotic cells. Results Wild-type RASSF1A, not the mutant, suppressed cell growth in vitro and in vivo. Re-expression of wild-type RASSF1A could enhance the inhibition of cell proliferation and the percentage of apoptotic cells following cell treatment with mitomycin, but had no significant effect when combined with adriamycin, etoposide, 5-fluorouracil and cisplatin treatment. Conclusion Wild-type RASSF1A inhibits cell growth and enhances cell chemosensitivity to mitomycin in hepatocellular carcinoma, suggesting that RASSF1A may serve as a new target for gene therapy in hepatocellular carcinoma patients.     

Induction of SiHa Cells Apoptosis by Nanometer Realgar Suspension and Its Mechanism

The effects of nanometer realgar uterine cervix cancer cell line SiHa cells and suspension on proliferation and apoptosis of human oncogenic genes HPV16E6/E7 were investigated. A ＂micro-jet effiux＂ strategy was used for the preparation of nanometer realgar suspension. SiHa cells were treated with nanometer Realgar suspension in various concentrations （6.25, 12.5, 25 and 50 mg/L） for different durations （12, 24, 48 and 72 h）. The inhibitive effect of nanometer realgar suspension on growth of SiHa cells was detected by MTT method. Special morphological changes of apoptosis were observed by transmission electron microscopy （TEM） and DNA fragments electrophoresis. The apoptotic rate was quantified by flow cytometry （FCM）. The expression of HPV 16E6/E7 mRNA and protein was assayed by RT-PCR and Western blot respectively. The results showed after being treated with 25--50 mg/L nanometer realgar suspension for 48 h, the survival rate of SiHa cells was decreased, and apoptotic rate markedly increased in a time- and concentration-dependent manner. TEM and DNA electrophoresis revealed the special morphological changes of apoptosis. The apoptotic rate of SiHa cells treated with nanometer realgar suspension was significantly higher than in the control group （P〈0.01）, and G0/G1 phase arrest appeared following treatment with nanometer realgar suspension in 25 and 50 mg/L for 48 h. RT-PCR and Western blot assay indicated that nanometer realgar suspension reduced the HPV16E6/E7 gene expression. Nanometer realgar suspension could inhibit the proliferation and induce apoptosis of SiHa cells. The mechanism may be related to the down-regulation of the HPV16E6/E7 gene expression.     

Effect of Quercetin on Proliferation and Apoptosis of Human Nasopharyngeal Carcinoma HEN1 Cells

The effect of quercetin （Que） on proliferation and apoptosis of human nasopharyngeal carcinoma HEN1 cells was investigated. Inhibition rate of quercetin on HEN1 was assayed by MTT method, apoptosis by flow cytometry （FCM）, and the caspase-3 expression of each group by colorimetry set respectively. Quercetin inhibited HEN1 cells in in a dose-（r=0.709, P〈0.01） and time-dependent manner （r=0.703, P〈0.01）. The ratio of apoptotic and necrosis cells was increased in the cells treated with quercetin. Cell cycle was specificly arrested in G2/M phase. Apoptosis cusp was revealed by FCM. The activity of caspase-3 was significantly up-regulated in 5 groups treated with quecetin as compared with control group （P〈0.05）. It was concluded that the growth inhibition of quercetin was highly related to cell cycle arrest at the G2/M phase and induction of caspase-dependent apoptosis in human nasopharyngeal carcinoma HEN 1 cells.     

Replication-incompetent Adenovirus Vector-mediated MDA-7/IL-24 Selectively Induces Growth Suppression and Apoptosis of Hepatoma Cell Line SMMC-7721

In order to investigate the effect of replication-incompetent adenovirus vector expressing MDA-7/IL-24 on tumor growth and apoptosis of human hepatocellular carcinoma （HCC） cell line SMMC-7721 and normal liver cell line L02, the recombinant replication-incompetent Ad.mda-7 virus vector was constructed and infected into the HCC cell line SMMC-7721 and normal liver cell line L02. RT-PCR was performed to examine the expression of MDA-7 mRNA. The concentrations of MDA-7/IL-4 in culture superuatants were determined by using ELISA. MTT and Hoechst staining assay were applied to observe the inhibitory and killing effects of MDA-7 on the HCC cells. By using flow cytometry, the apoptosis, cell cycle and proliferation of SMMC-7721 and L02 cells were measured. The results showed recombinant replication-incompetent virus expressing MDA-7/IL-24 was constructed successfully, and RT-PCR revealed that it could mediate the high expression of the exogenous gene MDA-7/IL-24 in SMMC-7721 and L02 cells. The expression of MDA-7/IL-24 proteins in the culture superuatant was detectable by ELISA. Ad.mda-7 infection induced apoptosis and growth suppression in SMMC-7721 cells and an increased percentage of HCC cells in the GyM phase of the cell cycle, but not in L02 cells. It was concluded that mda-7/IL-24 gene, mediated with replication-incompetent adenovirus vector, could selectively induce growth suppression and apoptosis in HCC cell line SMMC-7721 but without any toxic side-effect on normal liver line L02.     

Ursolic acid induces human hepatoma cell line SMMC-7721 apoptosis via p53-dependent pathway

Background Ursolic acid （UA） is a ubiquitous molecule in the plant kingdom with specific anticancer effects that have been shown in vitro and in vivo. Although UA can inhibit the proliferation of liver cancer cells and induce apoptosis of many types of tumor cells, the molecular mechanism of its anti-hepatoma activity is still not well defined. The objective of this study was to investigate the inhibitory effect and mechanisms of UA on the human hepatoma cell line SMMC-7721. Methods After treatment with UA, the growth inhibition of SMMC-7721 cells was assessed by MTT assay. Cells were also evaluated by flow cytometric analysis, Wright-Giemasa staining, Hoechst 33258 staining and transmission electron microscope after they were induced by UA. DNA microarray technology was used to investigate the gene expression pattern of SMMC-7721 cells exposed to UA 40 pmol/L. The molecular mechanism of cells death was analyzed by real-time RT-PCR and Western blotting. Results The proliferation of SMMC-7721 cells was significantly inhibited in a dose- and time-dependent manner after UA treatment. UA induced cell cycle arrest and apoptosis. The DNA microarray analysis indicated that 64 genes were found to be markedly up- or down-expressed, including GDF15, SOD2, ATF3, and fos. The result of Western blotting showed the apoptotic proteins p53 and Bax were up-regulated while the anti-apoptotic protein Bcl-2 was down-regulated. Real-time RT-PCR confirmed UA could up-regulate the mRNA expressions of GDF15, SOD2, ATF3 and down-regulate the mRAN expression of fos. Meanwhile these effects were partly blocked by pretreatment with the p53 inhibitor Pft-a. Conclusion Activation of the p53 pathway is involved in UA inhibition of SMMC-7721 human hepatocellular carcinoma cell growth and induction of apoptosis.     

DETECTION OF B LYMPHOMA CELLS UNDERGOING APOPTOSIS BY ANNEXIN—V ASSAY

Objecte.To quantitatively analyze apoptotic and secondary necrotic cells under apoptosis conditions.Methods.The cells of Burkitt lymphoma (BL) cell line Raji were incubated with 1.0μmol/L dexamethaone(DEX) for 2,4 and 8h respectively,then stained with Annexin V-FITC (fluorescein isothiocyanate conjugated)which was used to detect the exposed phosphatidylserine(PS) on the epimembrane resulting from a loss of phospholipid asymmetry in the early stage of apoptosis ,and also stained with propidium iodide(PI)which allows analysis of secondary necrotic cells related with cell membrane and DNA damage that probably represent late stage of apoptosis,then apoptotic cells were quantified by flow cytometry(FCM).Furthermore,Annexin^ /PI^- and Annexin^ /PI^ cells were sorted by fluoresence-activated cell sorter(FACS),and identified by electron microscopy(EM)and DNA gel electrophoresis.Reuslts.The percentage of apoptotic cells was fund to increase with the incubation time(r=0.97).This method was senitive with low detection limit(0.02%) ,and was reproducible with low coefficient variance (CV)(4.2%).Meanwhile,the Annexin^ /PI^- and Annexin^ /PI^- cells were identified as apoptotic and necrotic cells under EM,and DNA extracted from the Annexin^ /PI^- cell was characteriazed by “ladder pattern“.Conclusions.Annexin-V assay is a specific,sensitive,accurate,reproductive and quantitative method for analyzing apoptotic cells.     

Effects of the Extract of Ammopiptanthus mongolicus cheng f. （JA1） on Induction of Apoptosis of HepG2 in vitro and Its Molecular Mechanisms

Objective To study the effects and the mechanisms of extract from a leguminous plant （Ammopiptanthus mongolicus cheng f.） （JAl ） in northwest China on inducing apoptosis and inhibiting proliferation of HepG2 hepatocarcinoma cell in vitro. Methods The HepG2 cell line was used as target cells. The effect of 3A 1 on HepG2 cell growth was detected by microculture tetrazolium assay （MTr）, flow cytometry assay, DNA agarose gel electrophoresis and transmission electronic microscopy. The expressive effect of the wt-p53 in HepG2 cells was analyzed with p53 protein test-reagent. Results JAl not only had significant anti-proliferative effects depending upon time and dosage, but also induced apoptosis of HepG2 cells. Apoptotic typical morphological changes were observed in JAl-treated HepG2 cells under transmission electronic microscope, ＂Sub-G 1＂ phase peak occurred in flow cytometry and DNA ＂ladder＂ was found in DNA agarose gel electrophoresis. The expression of the wt-p53 increased in vitro, and 3Al-treated HepG2 and the positive cell percentage of the wt-p53 protein also increased. Conclusions JAl could obviously induce apoptosis and inhibit proliferation of HepG2 cells in vitro, and these effects are closely related with the increase of wt-p53 expression. JAl can be used as a good source of medicinal plant for the treatment of hepatocarcinoma.     

Suppressive effects of genomic imprinted gene PEG10 on hydrogen peroxide-induced apoptosis in L0<Subscript>2</Subscript> cells

The effects of PEG10 on hydrogen peroxide （H2O2）-induced apoptosis in human normal liver cell line L02 were investigated. The PEG10 gene was transfected into L02 cells by lipofectamine, the positive clone was screened by G418 and defined as L02/PEG10, while the cell transfected with empty expression vector （pEGFP-N1） was defined as L02/vector. L02/vector and parental L02 cells served as control. RT-PCR and Western blotting were employed to detect the expression of target genes. H2O2 （50–400 mmol/L） was administered to induce the apoptosis of L02 cells. Cells viability was measured by MTT and the morphological changes of apoptotic cells were determined by fluorescence microscopy using hoechst33342 nuclei staining. DNA fragmentation was observed by agarose gel electrophoresis. PEG10 mRNA and protein levels in L02/PEG10 cells were significantly increased as compared with those in the control cells. After treatment with 400 mmol/L H2O2 for 24 h, the cellular growth inhibition rate of L02/PEG10 cells was significantly lower （58.2%） than that of L02 （92.5%） and L02/vector （88%）. Distinct morphological changes characteristic of cell apoptosis such as karyopyknosis and conglomeration were not observed in L02/PEG10. Ladder-like DNA fragmentation in a dose-dependent manner was observed in both L02 and L02/vector cell lines, but not in L02/PEG10. PEG10 over-expression significantly inhibited cytotoxicity induced by H2O2 on human normal liver cell line L02 by antagonizing H2O2-induced apoptosis.     

Cytotoxic Activities of Total Saponins from Plena Clematis on Human Tumor Cell Lines In Vitro

Objective: To investigate the anti-proliferative effects of saponins prepared from Plena Clematis (PC) cultured in Fujian Province, China on 4 human tumor cell lines and its possible anti-tumor mechanism. Methods: The growth inhibition assays of saponins on human esophageal squamous carcinoma cell line (EC9706), human hepatoma cell line (HepG-2), human oral cancer cell line (KB) and human gastric cancer cell line (BGC-823) were evaluated in vitro by thiazolyl blue (MTT) method. The inhibitory effects on EC9706 treated with different concentrations of saponins (15.62, 31.25, 62.50, 125, 250 and 500 μg/mL) were performed in vitro by MTT method. The morphology and nuclear staining with acridine orange/ethidium bromide of EC9706 cells treated with saponins were illustrated under an inverted phase fluorescence microscope. The apoptotic effects of saponins were further evaluated by annexin-V/propidium iodide dual staining experiment to examine the occurrence of phosphatidylserine externalization onto the cell surface by a flow cytometer. Results: MTT assay showed that the saponins could inhibit the proliferation of 4 tumor cell lines. Among them, the maximum inhibition rate of 73.1% was detected in EC9706 cells at the saponins concentration of 250 μg/mL for 24 h. Further investigation indicated that the saponins induced EC9706 cells apoposis. The EC9706 cells presented apoptotic characteristics when treated with saponins, including that the morphologies of EC9706 cells were appeared round-shaped with higher refraction, and the cell nuclear stained orange with EB after 250 μg/mL saponins exposure. The flow cytometry analysis results showed that the induction of cell cycle arrest in apoptotic system may participate in the anti-proliferative activity of saponins on EC9706 cells. Conclusion: The saponins from PC exhibited significant cytotoxicity against human EC9706, KB, BGC-823, and HepG-2 cells and might be beneficial to development of ethnic pharmaceutical plant for potential anti-tumor drugs.     

Enhanced effects of TRAIL-endostatin-based double-gene-radiotherapy on suppressing growth, promoting apoptosis and inducing cell cycle arrest in vascular endothelial cells

This study examined the effects of TRAIL-endostatin-based gene-radiotherapy on cellu-lar growth, apoptosis and cell cycle progression in human vascular endothelial cells ECV304 in vitro. The expression of TRAIL and endostatin protein in ECV304 cells was detected by ELISA after the transfection of recombinant plasmid pshuttle-Egr1-shTRAIL-shES and X-ray irradiation. Then MTT assay was used for determining the cellular proliferation, and flow cytometry (FCM) plus Annexin V and propidium iodide (PI) double-staining or PI single-staining were employed for the detection of apoptosis and cell cycle progression. The results showed that expression of TRAIL and endostatin protein exhibited a time- and dose-dependent change in ECV304 cells after pshut-tle-Egr1-shTRAIL-shES transfection in conjunction with irradiation. In the TRAIL-endostatin-based single- or double-gene-radiotherapy, the cell viability declined in a time- and dose-dependent manner, the percentage of cells at G2/M phase and apoptotic rate was increased, and the percentage of cells at G0/G1 phase was lowered as compared with those receiving radiotherapy alone. Moreover, TRAIL-endostatin-based double-gene-radiotherapy demonstrated better effects on growth inhibition, promotion of apoptosis and induction of cell cycle arrest in ECV304 cells than sin-gle-gene-radiotherapy.     

Expression of EPO Receptor in Pancreatic Cells and Its Effect on Cell Apoptosis

In order to explore the expression of erythropoietin receptor （EPOR） in pancreatic cell line NIT-1 and its effect on cell apoptosis after binding with erythropoietin （EPO）, NIT-1 cells were cultured and expanded. The expression of EPOR was detected using electrophoresis. NIT-1 apoptosis was induced by cytokines and their effects on cell apoptosis and cell insulin secretion were assayed after binding of EPO to EPOR. The results showed that EPOR was expressed in NIT-1 cells. Recombinant human EPO （rHuEPO） had no effect on cell apoptosis but significantly inhibited apoptosis induced by cytokines, rHuEPO had no effect on cell insulin secretion but significantly improved insulin secretion inhibited by cytokines. From these findings, it was concluded that EPOR was expressed in NIT- 1 cells and EPO could protect NIT- 1 cells from apoptosis induced by cytokines.