Downregulation of alpha-fetoprotein siRNA inhibits proliferation of SMMC-7721 cells

AIM: To study the function of α-fetoprotein (AFP) in SMMC-7721 hepatoma cells.METHODS: A hairpin siRNA expressing plasmid pSilencer3.0-H1-afp was constructed and transfected into SMMC-7721 cells with Lipofectamine 2000. The expression of AFP was monitored by real-time RT-PCR and immunoassays, its effect on SMMC-7721 cell proliferation and cell death was detected by MTT and fluorescenceactivated cell sorter (FACS).RESULTS: The AFP-siRNA expressing plasmid downregulated the expression of AFP obviously (about 34%), and inhibited SMMC-7721 cell proliferation, but did not induce apoptosis.CONCLUSION: Downregulation of AFP siRNA inhibits proliferation of SMMC-7721 cells, but cannot cause apoptosis.

Effects of cytotoxic T lymphocytes on hepatoma cell line SMMC-7721 induced by different subsets of dendritic cells in vitro

BACKGROUND: Dendritic cells (DCs) loaded with complex antigen are always used to induce cytotoxic T lymphocytes (CTLs) which have a specific anti-tumor activity. However, CTLs can assault autologous cells induced by DCs loaded with autologous antigen. This study aimed to explore how to weaken the autoimmune reaction induced by DC vaccine by combining mature DC (mDC) activating immunity and immature DC (imDC) leading to immune tolerance to make hepatocellular carcinoma (HCC) vaccine in vitro. METHODS: DC progenitors derived from human peripheral blood were assigned to two groups. One was cultured to mDC and pulsed with frozen-thawed antigen (FTA) of human HCC cell line SMMC-7721 cells (mDC group), and the other was cultured to imDC and pulsed with FTA of human liver cell line L-02 cells (imDC group). The morphology of DCs was monitored and cells phenotypes including HLA-DR, CD80, CD1α, CD83 were assayed by flowcytometry (FCM). The concentrations of interleukin-12 (IL-12) in the supernatant were assayed by ELISA. Methyl thiazolyl tetrazolium (MTT) was used to evaluate T cell proliferation induced by mDC and imDC and the killing rate of CTL induced by mDC and imDC respectively/together on SMMC-7721 and L-02 cells. RESULTS: Compared with the imDC group, the mDC group was characterized by the following: increased secretion of IL-12 (P【0.05); higher expression of HLA-DR, CDla, CD80, CD83; and stronger activity in stimulating proliferation of isogenic T cells (P【0.05). CTL induced by the mDC group had a significant killing response to SMMC-7721 as well as a higher killing rate for L-02 (P】0.05). CTL induced by mDC and imDC together had a higher killing response to SMMC-7721, but a lower killing rate for L-02(P【0.01). CONCLUSIONS: CTL induced by mDC and imDC together has a higher antigen-specific killing response in vitro than that induced by mDC alone. This may be of greater clinical value.

Positional and expressive alteration of prohibitin during the induced differentiation of human hepatocarcinoma SMMC-7721 cells

AIM： To explore the existence and distribution of prohibitin （PHB） in nuclear matrix and its co-localization with products of some related genes during the differentiation of human hepatocarcinoma SNMC-7721 cells. METHODS： The nuclear matrix of the SMMC-7721 cells cultured with or without 5 × 10^-3 mmol/L hexamethylene bisacetamide （HNBA） was selectively extracted. Western blot was used to analyze the expression of PHB in nuclear matrix; immunofluorescence microscope observation was used to analyze the distribution of PHB in cell. LCSM was used to observe the co-localization of PHB with products of oncogenes and tumor suppressor genes. RESULTS： Western blot analysis showed that PHB existed in the composition of nuclear matrix proteins and was down-regulated by HMBA treatment. Immunofluorescence observation revealed that PHB existed in the nuclear matrix, and its distribution regions and expression levels were altered after HMBA treatment. Laser scanning confocal microscopy revealed the co-localization between PHB and the products of oncogenes or tumor repression genes including c-los, c-myc, p53 and Rb and its alteration of distributive area in the cells treated by HMBA. CONCLUSION： These data confirm that PHB is a nuclear matrix protein, which is located in the nuclear matrix, and the distribution and expression of PHB and its relation with associated genes may play significant roles during the differentiation of SMMC-7721 cells.

Serum deprivation enhances DNA synthesis of human hepatoma SMMC-7721 cells

AIM To determine the relationship between serum deprivation or serum levels and cell proliferation of human hepatoma SMMC 7721 cells. METHODS Human hepatoma SMMC 7721 cells were grown in RPMI 1640 supplemented with 10% fetal calf (FCS) in 5% CO 2 incubator at 37℃ for 24h , and culture media were replaced to serum free or different serum FCS levels (2 5%, 5%, 10%, 20% and 25%). Six h, 12h , 18h and 24h after the culture, the cells were incorporated TdR for 4h . At last TdR incorporation was detected with liquid scintillation counting. RESULTS DNA synthesis of SMMC 7721 cells could be sharply stimulated by short time (6h) serum deprivation (the cpm value of 3H TdR incorporation of cells in serum free was 39 32 fold higher than cells in 25% serum), and the incorporation of 3H TdR was negatively related to the serum levels. Longer time serum starvation ( 12h , 18h and 24h ) also greatly stimulated DNA synthesis, although the cpm value of 3H TdR incroporation was less than that in 6h serum deprivation. Morphology of cells cultured in different serum levels also showed significant difference. CONCLUSIONS Compared with other cell lines such as BEL7404 and Swiss 3T3, human hepatoma SMMC 7721 cells had different response to the serum deprivation. Short time serum deprivation could greatly stimulate DNA synthesis of human hepatoma SMMC 7721 cells. Precautions must be given to the changes of serum levels for the detection of growth factors and drugs using SMMC 7721 cells as a model.

Anti-cancer Effects of Deguelin on Human Leukemia K562 and K562/ADM Cells In Vitro

In order to investigate the anti-cancer effects of deguelin and on K562 and K562/ADM cells in vitro and the underlying molecular mechanism and compare the cytotoxicity of deguelin on K562, K562/ADM cells and human peripheral blood mononuclear cells （PBMCs）. The effects of deguelin on cell proliferation were assessed by MTT assay. Apoptosis were detected by Annexin V/PI double-labeled cytometry. The effects of deguelin on the cell cycle were studied by a propidium iodide method. Our study showed that deguelin inhibited the proliferation of K562 cell and K562/ADM cell in a time- and dose-dependent manner and had minimal effects on normal human peripheral blood mononuclear cells. The ratio of IC50 value of deguelin of 24 h on K562/ADM cells to K562 cells was only 1.27, which was significantly lower than the ratio of IC50 value of ADM （higher than 20）. Deguelin could induce apoptosis of K562 cells and K562/ADM cells. K562 cells were arrested at G2/M phase while K562/ADM cells were arrested at G0/G~ phase. Our results suggested that deguelin was a novel anti-leukemia agents with high efficacy and low toxicity and it is also a promising agent for reversing drug resistance.

白藜芦醇通过下调PRMT5表达抑制肝胆管癌SMMC-7721细胞的增殖、侵袭和细胞周期

目的:探究白藜芦醇(Res)通过调控PRMT5表达对肝胆管癌SMMC-7721细胞增殖、侵袭、细胞周期的影响及其机制。方法:常规培养正常肝细胞LO2和SMMC-7721细胞,用0、20、40、80μmol/L的Res进行处理,用qPCR法、MTT法、Transwell实验、流式细胞术和WB法分别检测Res处理后PRMT5 mRNA在LO2和SMMC-7721细胞中的表达,Res对SMMC-7721细胞增殖能力、侵袭能力、细胞周期和凋亡,以及PRMT5、cyclin D1和cyclin E1蛋白表达的影响。结果:PRMT5在SMMC-7721细胞中呈高表达(P<0.01);20、40、80μmol/L Res均能明显抑制PRMT5 mRNA和蛋白在SMMC-7721细胞中的表达(均P<0.01),抑制SMMC-7721细胞的增殖能力(P<0.01)和侵袭能力(P<0.05),阻滞SMMC-7721细胞周期于G0/G1期并促进其凋亡(P<0.01),明显抑制SMMC-7721细胞中周期蛋白cyclin D1、cyclin E1蛋白的表达(P<0.01)。结论:PRMT5在SMMC7721细胞中呈高表达,Res可有效抑制SMMC-7721细胞的增殖和侵袭能力并诱导其凋亡,其机制可能与抑制PRMT5表达相关。

人肝癌细胞耐药模型-7721/Adm的建立及其部分生物学特性

建立耐药肝癌细胞模型 7721/Adm并研究其生物学特性。方法 :应用人肝癌细胞株 7721(简称7721细胞株 ) ,采用阿霉素 (Adm)高浓度间歇诱导法 ,建立耐药人肝癌细胞模型 7721/Adm(简称7721/Adm细胞株 )。观察该细胞的生长规律 ;用MTT法检测该耐药细胞模型的多药耐药性 ;以流式细胞术检测该耐药模型细胞周期中的分布、细胞表面多药耐药基因 (mdr)的表达产物P 糖蛋白 (P gp)、多药耐药相关蛋白 (MRP)及谷胱甘肽硫转移系统 (GSH/GST)的表达等。结果 :1 经MTT法检测7721/Adm细胞较HCC 7721细胞的阿霉素半数抑制浓度 (IC50)增大99 9倍 ,并对多种抗癌药物产生耐药性。2 耐药细胞的倍增时间明显延长 ,S期细胞减少 ,G1、G2 期细胞增多。3 该耐药模型细胞表面多药耐药基因 (mdr)的表达产物P 糖蛋白 (P gp)、多药耐药相关蛋白 (MRP)有非常显著的升高 (P<0 01) ,P gp 表达为94 6 %、MRP表达为69 4% ,而谷胱甘肽硫转移系统 (GSH/GST)的表达无明显变化 (P>0 05)。结论 :7721/Adm细胞是一个明确的多药耐药模型 ;具有耐药细胞的基本生物学特性 :同亲本细胞相比 ,IC50提高99 9倍、倍增时间延长4 2倍、细胞内药物蓄积明显降低、细胞周期分布发生变化 ;其多药耐药性与P gp。

阿霉素对热处理的人肝癌细胞-7721/Adm耐药株细胞毒性的影响

目的： 探讨比较阿霉素（ ADM）与 43℃加热单独或合并处理人肝癌细胞 7721敏感株（简称 7721细胞）和人肝癌细胞 7721/Adm耐药株（简称 7721/Adm细胞）的细胞毒作用。方法：以体外培养的人肝癌细胞 7721敏感株和已经建立的人肝癌细胞 7721/Adm耐药株为研究对象，采用水浴加温法 ,体外细胞毒试验（ MTT法） ,观察 ADM与加热处理对细胞生长抑制的影响；采用流式细胞技术检测热处理对 7721细胞和 7721/Adm细胞胞内阿霉素浓度的影响。结果： (1)热处理可以明显提高两种细胞对阿霉素的敏感性： 7721细胞、 7721/Adm细胞经阿霉素及 43.5℃热处理，其细胞存活率分别下降 35.2％（ 30 min）、 24.8％（ 60 min）和 29.4％（ 30 min）、 22.8％（ 60 min）； (2)流式细胞仪检测显示，热处理可明显提高这两种细胞尤其是 7721/Adm细胞内的阿霉素浓度： 7721细胞组提高 30.8％， HCC 7721/Adm组提高 51％。结论：热处理可以显著提高人肝癌细胞 7721敏感株和人肝癌细胞 7721/Adm耐药株对阿霉素的敏感性。

人肝细胞癌耐阿霉素细胞亚株SMMC-7721/ADM的诱导及其特征研究

目的 建立人肝细胞癌多药耐药亚株并对其主要特征进行研究。方法 应用SMMC 772 1细胞株 ,通过不断提高培养液中阿霉素 (ADM)的浓度 ,长期筛选培养 ,得到了人肝细胞癌多药耐药亚株SMMC 772 1/ADM后 ,对其特征进行研究。结果 ①SMMC 772 1/ADM对ADM的抗药性提高了 33.3倍 ,对长春新碱的抗药性提高了 16 .8倍 ,对顺铂的抗药性提高了 2 .8倍 ;②耐药细胞与亲代细胞的生长速度基本相同 ,倍增时间分别为 32 .0h和 30 .5h ,呈现相似的生长曲线 ;③利用扫描和透射电镜发现 ,耐药细胞与亲代细胞形态上的明显差别是前者微绒毛变得粗短、稀疏、分布不均 ;④耐药细胞保持着肝细胞癌的特征 ,能在裸小鼠皮下移植再现 ;⑤SMMC 772 1/ADM在去药培养 1个月和 2个月后耐药指数下降为 2 8.0 %和 9.2 % ,而在ADM( 0 .0 4 μg/ml)存在下生长 2个月后 ,耐药倍数可保持稳定 ( 35 .4倍 )。结论 SMMC 772 1/ADM细胞亚株具有稳定的耐药性细胞株的基本特征。

耐药人肝癌细胞模型-7721/Adm的建立

目的 培养建立耐药肝癌细胞模型 - 772 1/ Adm并研究其生物学特性 .方法 应用人肝癌细胞株 - 772 1(以下简称772 1细胞 ) ,采用阿霉素 (Adm )大剂量间歇诱导法 ,建立耐药人肝癌细胞模型 - 772 1/ Adm (以下简称 772 1/ Adm ) .观察该细胞的生长规律 ;用 MTT法鉴定该耐药细胞模型对多种抗癌药物的多药耐药性 ;以流式细胞技术检测该耐药细胞模型细胞周期分布、细胞表面多药耐药基因 (MDR)的表达产物 - P-蛋白 (P- gp)、多药耐药相关蛋白 MRP及谷胱甘肽硫转移系统(GSH/ GST)的表达等 .结果 1经 MTT法鉴定 772 1/ Adm细胞较 HCC- 772 1细胞的阿霉素半数致死浓度 (IC5 0 )增大4.6 5倍 ,并对多种抗癌药物产生耐药性 ,其耐药性提高了 2～6倍不等 ;2耐药细胞倍增时间明显延长 ,S期细胞减少 ,而G2期细胞增多 ;3该耐药模型 P- gp,MRP表达有非常显著的升高 (P<0 .0 1) :P- gp表达为 94.6 % ,MRP表达为 6 9.4% ,而 GSH/ GST的表达无明显变化 (P<0 .0 5 ) .结论 1HCC-772 1/ Adm是一个明确的多药耐药细胞模型 ;2 772 1/

川芎嗪对肝癌多药耐药株SMMC-7721/ADM的逆转作用

目的研究川芎嗪对肝癌多药耐药株SMMC-7721/ADM的逆转及其机制。方法用MTT法检测常用化疗药物对SMMC-7721/ADM的毒性。用流式细胞仪(FCM)检测SMMC-7721/ADM细胞表面P糖蛋白(Pgp)的表达及细胞内柔红霉素的相对浓度。结果川芎嗪可提高SMMC-7721/ADM细胞内化疗药物的浓度,增加阿霉素等化疗药物对SMMC7721/ADM的毒性作用。结论川芎嗪可逆转人肝癌多药耐药株SMMC-7721/ADM,其机制可能与胞内ADM浓度有关。

Reversal of Multidrug Resistance by Neferine in Adriamycin Resistant Human Breast Cancer Cell Line MCF-7/ADM

Objective: To study the reversal effect of neferine on adriamycin (ADM) resistant human breast cancer cell line MCF-7/ADM. Methods: The cytotoxic effect of Nef or ADM was determined by 3-[4, 5-dimethylthiazol-2.-yl], 5-diphenyl tetraxolium bromid (MTT) assay. Apoptosis and the expression of P-glycoprotein (P-gp) were detected by flow cytometry (FCM). The intracellular ADM concentration was measured by HPLC. Results: Nef at 1, 5, 10 mol/L decreased the IC50 of ADM to MCF-7/ADM from 11.63 g/mL to 4.59, 2.44, 0.27 g/mL respectively. MCF-7/ADM could resist the apoptosis induced by ADM while Nef (1-10 mol/L) could augment ADR-mediated apoptosis. Nef (10 mol/L) increased the accumulation of ADM up to 2.88 fold in MCF-7/ADM but not in sensitive cells MCF-7/S and reduced the expression of P-gp in MCF-7/ADM cells. Conclusion: Nef can circumvent multidrug resistance (MDR) of MCF-7/ADM cells and the mechanism was associated with the increase of intracellular accumulation of ADM and the reduced expression of P-gp in MCF-7/ADM cells.

Activity Determination of 8 Chinese Herbs against Hepatoma Cell SMMC-7721 in Vitro by MTT Method

[Objective] The aim was to build up a set of efficient and rapid models for laboratory to screen anti-hepatocellular carcinoma active substance in vitro. [ Method] By using MTT method, the activities of anti-hepatocellular carcinoma SMMC-7721 in vitro from Cymbopogon distans, Lobelia chinensis, Buddleja offlcinalis, Glycyrrhiza uralensis, Sanguisorba officinalis, Bupleurum chinense, Apium graveolen and Curuma zedoaria were tested. The growth curve of hepatoma cell was described, and the growth status in different periods were observed by inverted microscope. [ Result] Cells induced by active substance would be condensing, clear brim, which have significant differences from normal SMMC- 7721 cells. The results suggested that ESCG, ESCC, ESCB could inhibit proliferation of SMMC-7721 cells at the concentration of 1.0 -1.5 mg/ml, and the inhibition rate were 51.6%, 48.5%, 52.9% respectively. With the increasing of concentration, the inhibition strengthened. [ Conclusion] MTT method could be used as a basic model for screening important anti-hepatoma.

Holotransferrin Enhances Selective Anticancer Activity of Artemisinin against Human Hepatocellular Carcinoma Cells

Artemisinin, also termed qinghaosu, is extracted from the traditional Chinese medicine ar- temesia annua L. （the blue-green herb） in the early 1970s, which has been confirmed for effectively treating malaria, Additionally, emerging data prove that artemisinin exhibits anti-cancer effects against many types of cancers such as leukemia, melanoma, etc. Artemisinin becomes cytotoxic in the presence of ferrous iron. Since iron influx is high in cancer cells, artemisinin and its analogs selectively kill can- cer cells with increased intracellular iron concentrations. This study is aimed to investigate the selective inhibitory effects of artemisinin on SMMC-7721 cells in vitro and determine the effect of holotransfer- fin, which increases the concentration of ferrous iron in cancer cells, combined with artemisinin on the anticancer activity. MTT assay was used for assessing the proliferation of SMMC-7721 cells treated with artemisinin. The induction of apoptosis and inhibition of colony formation in SMMC-7721 cells treated with artemisinin were determined by TdT-mediated dUTP nick end labeling （TUNEL） and col- ony formation assay, respectively. The results showed that artemisinin at various concentrations signifi- cantly inhibited growth, colony formation and cell viability of SMMC-7721 cells （P〈0.05）, likely due to induction of apoptosis of SMMC-7721 cells. Of interest, it was found that incubation of artemisinin combined with holotransferrin sensitized the growth inhibitory effect of artemisinin on SMMC-7721 cells （P〈0.01）. Our data suggest that treatment with artemisinin leads to inhibition of viability and pro- liferation, and apoptosis of SMMC-7721 ceils. Furthermore, we observed that holotransferrin signifi- cantly enhanced the anti-cancer activity of artemisinin. This study may provide a potential therapeutic choice for liver cancer.

High-density lipoprotein as a potential carrier for delivery of a lipophilic antitumoral drug into hepatoma cells

AIM: To investigate the possibility of recombinant highdensity lipoprotein (rHDL) being a carrier for delivering antitumoral drug to hepatoma cells. METHODS: Recombinant complex of HDL and aclacinomycin (rHDL-ACM) was prepared by cosonication of apoproteins from HDL (Apo HDL) and ACM as well as phosphatidylcholine. Characteristics of the rHDL-ACM were elucidated by electrophoretic mobility, including the size of particles, morphology and entrapment efficiency. Binding activity of rHDL-ACM to human hepatoma cells was determined by competition assay in the presence of excess native HDL. The cytotoxicity of rHDL-ACM was assessed by MTT method. RESULTS: The density range of rHDL-ACM was 1.063-1.210 g/mL, and the same as that of native HDL. The purity of all rHDL-ACM preparations was more than 92%. Encapsulated efficiencies of rHDL-ACM were more than 90%. rHDL-ACM particles were typical sphere model of lipoproteins and heterogeneous in particle size. The average diameter was 31.26±5.62 nm by measure of 110 rHDL-ACM particles in the range of diameter of lipoproteins. rHDL-ACM could bind on SMMC-7721 cells, and such binding could be competed against in the presence of excess native HDL. rHDL-ACM had same binding capacity as native HDL. The cellular uptake of rHDL-ACM by SMMC-7721 hepatoma cells was significantly higher than that of free ACM at the concentration range of 0.5-10 μg/mL (P<0.01). Cytotoxicity of rHDL-ACM to SMMC-7721 cells was significantly higher than that of free ACM at concentration range of less than 5 ug/mL (P<0.01) and IC50 of rHDL-ACM was lower than IC50 of free ACM (1.68 nmol/L vs3 nmol/L). Compared to L02 hepatocytes, a normal liver cell line, the cellular uptake of rHDL-ACM by SMMC-7721 cells was significantly higher (P<0.01) and in a dose-dependent manner at the concentration range of 0.5-10 μg/mL.Cytotoxicity of the rHDL-ACM to SMMC- 7721 cells was significantly higher than that to L02 cells at concentration range of 1-7.5μg/mL (P<0.01). IC50 for SMMC-7721 cells (1.68 nmol/L) was lower than that for L02 cells (5.68 nmol/L), showing a preferential cytotoxicity of rHDL-ACM for SMMC-7721 cells. CONCLUSION: rHDL-ACM complex keeps the basic physical and biological binding properties of native HDL and shows a preferential cytotoxicity for SMMC-7721 hepatoma to normal L02 hepatocytes, HDL is a potential carrier for delivering lipophilic antitumoral drug to hepatoma cells.

Protein profile of human hepatocarcinoma cell line SMMC-7721:Identification and functional analysis

AIM： TO investigate the protein profile of human hepatocarcinoma cell line SMMC-7721, to analyze the specific functions of abundant expressed proteins in the processes of hepatocarcinoma genesis, growth and metastasis, to identify the hepatocarcinoma-specific biomarkers for the early prediction in diagnosis, and to explore the new drug targets for liver cancer therapy. METHODS： Total proteins from human hepatocarcinoma cell line SMMC-7721 were separated by two-dimensional electrophoresis （2DE）. The silver-stained gel was analyzed by 2DE software Image Master 2D Elite. Interesting protein spots were identified by peptide mass fingerprinting based on matrix-assisted laser desorption/ ionization time-of-flight mass spectrometry （MALDI-TOF-MS） and database searching. RESULTS： We obtained protein profile of human hepatocarcinoma cell line SMMC-7721. Among the twenty-one successfully identified proteins, mitofilin, endoplasmic reticulum protein ERp29, ubiquinol-cytochrome C reductase complex core protein I, peroxisomal enoyl CoA hydratase, peroxiredoxin-4 and probable 3-oxoacid CoA transferase 1 precursor were the six novel proteins identified in human hepatocarcinoma cells or tissues. Specific functions of the identified heat-shock proteins were analyzed in detail, and the results suggested that these proteins might promote tumorigenesis via inhibiting cell death induced by several cancer-related stresses or via inhibiting apoptosis at multiple points in the apoptotic signal pathway. Other identified chaperones and cancer-related proteins were also analyzed.CONCLUSION： Based on the protein profile of SMMC-7721 cells, functional analysis suggests that the identified chaperones and cancer-related proteins have their own pathways to contribute to the tumorigenesis, tumor growth and metastasis of liver cancer. Furthermore, proteomic analysis is indicated to be feasible in the cancer study.

Inhibitory activity of polysaccharide extracts from three kinds of edible fungi on proliferation of human hepatoma SMMC-7721 cell and mouse implanted S180 tumor

AIM To determine the activities ofpolysaccharide extracts from Flammulina velutipes (Curt. ex Fr. ) Sing (FV), Lentinusedodes (LE) and Agaricus bisporus Sing (AB)on the proliferation of human hepatoma SMMC-7721 cells in vitro and on mouse implanted S-180tumors in vivo.METHODS The polysaccharide extracts were isolated from the fruit bodies of FV, LE and AB by the methods of hot-water extraction, Sevag’sremoval of proteins, ethanol precipitation,trypsin digestion and ethanol fractionalprecipitation. Human hepatoma SMMC-7721 cells were treated with 50 mg/L Polysaccharide extracts, and the mitosis index, mitochondria activity and cell proliferation were detected at different times in both control and experimental groups. The mice with S-180 implanted tumors were injected with the polysaccharide extracts at 24 mg/ kg body weight for 9 d and the tumorweight was measured on the 15th day.RESULTS The mitosis index of hepatoma cells in vitro could be significantly decreased by treatment with the polysaccharide extracts fromthe three kinds of edible fungi (P < 0 .005 ). Thecell numbers and mitochondria activity of SMMC7721 cells treated with polysaccharide extracts were lower than those in control groups (P <0.005). The inhibition rates of polysaccharide extracts against implanted S-180 tumors in mice were 52.8%, 56.6% and 51 .9% respectivelycompared with that in c0ntrol gr0ups.CONCLUSI0N The POIysaccharide extractsfrom the three kinds of edible fungi could inhibitnot only the Cultured malignant cells in vitfO butalso impIanted Sl80 tum0r i0 vivo.

Docetaxel shows radiosensitization in human hepatocellular carcinoma cells

AIM: To determine the radiosensitizing potential of docetaxel in human hepatocellular carcinoma SMMC-7721 cells and its mechanisms.METHODS: SMMC-7721 cells were incubated with docetaxel at 0.125, 0.25, and 0.5 nmoL/L for 24 h and at 0.125 and 0.25 nmol/L for 48 h before irradiation. Radiation doses were given from 0 to 10 Gy. Cell survival was measured by a standard clonogenic assay after a 9-d incubation. The reactive oxygen species (ROS) and glutathione (GSH) are detected after being given the same dose of docetaxel for the same time. RESULTS: The sensitization enhancement ratios (SER) for SMMC-7721 cells determined at the 50% survival level were 1.15, 1.21 and 1.49 at 0.125, 0.25, and 0.5 nmol/L for pre-incubation of 24 h, respectively; the SER were 1.42, 1.67 at 0.125 and 0.25 nmol/L, for pre-incubation of 48 h, respectively. The ROS of SMMC-7721 cells increased and GSH decreased after pretreatment with the same doses of docetaxel for 24 or 48 h.CONCLUSION: A radiosensitizing effect of docetaxel could be demonstrated unambiguously in this cell line used. In addition, our data showed that the mechanism of radiopotentiation by docetaxel probably does not involve a G2/M block in SMMC-7721 cells, and ROS generation and GSH deletion may play a key role in the radiosensitizing effect of docetaxel.

INDEPENDENT AND SYNERGIC INHIBITION OF DIPYRIDAMOLE AND RADIATION ON K562-AND K562/ADM CELL LINES IN VITRO

It is first demonstrated that dipyridamole (DP) and radiation were capable of significantly inhibiting, independently and synerglcally, clonogenlc growth in the two kinds of K562 cell lines, adriamycin (ADM) -sensitive and ADM- resistant. DP or radiation alone Increased clonogenlc Inhibition rate (CIR) in the two kinds of cell lines in a dose- dependent fashion. DP potentiated radiosensitivity and radiation increased inhibition of DP in the two kinds of cell lines. K562/ ADM cell lines were higher sensitive to DP. radiation and combination of them than K562 cell lines (P<0. 01). There was stronger synergic inhibition of clonogenlc growth in the two kinds of cell lines when pretreated with DP than when posttreated with DP (P<0. 01).

INDEPENDENT AND SYNERGIC INHIBITION OF VERAPAMIL AND ELECTRIC BEAM RADIATION ON CLONOGENIC GROWTH IN K562 AND K562/ADM CELL LINES IN VITRO

It was first reported here that verupamil(VP) and electric beam radiation(EBR) were capable of inhibiting,independently or synergically,clonogenic growth in two kinds of K562 cell lines, adriamycin(ADM)-sensitive and ADM-resistant(K562/S and K562/ADM).Results showed that clonogenic rate(CGR) decreased by 3%-99.9% in the prasence of dependent dose-ADM(3.8μg/ml) in K562/ADM cell lines,while treated with 0.5μM-6μM of VP.VP was capable of potentiating radiosensitivity in K562/S and K562/ADM cell lines,whether before or after exposure of them to electric beam radiation,and significantly reduced CGR in these kinds of cell lines(P<0.01).