NS-398对人肝癌BEL-7402细胞凋亡作用及其机制的研究

目的：本研究应用NS-398对肝癌细胞株进行药物干预，探讨NS-398对肝细胞癌凋亡的影响。方法：NS-398取0、25、50、75、100μmol／L 5个浓度组，每个浓度组选取24h、48h、72h三个作用时间点。MTT法测定生长抑制情况，FCM检测细胞周期、凋亡率和Survivin、cyclin D1、PTEN的表达。结果：NS-398可以显著抑制BEL-7402细胞增殖，使G0／G1期比例显著降低；G2／M期比例显著增高并且诱导细胞凋亡（P〈0．001），并呈时间和剂量依赖性。与对照组相比．NS-398使Survivin、cyclin D1、PTEN蛋白表达显著下调并呈时间和剂量依赖性关系（P〈0．001）．结论：NS-398可诱导BEL-7402细胞凋亡．可能部分通过下调Survivin和PTEN途径实现的。     

肝、胆

丙型肝炎病毒NS4B对肝细胞c-myc和ras蛋白表达的研究；放射与抗VEGF抗体对人肝癌移植瘤生长的抑制作用；ki-67反义寡核苷酸抑制人肝癌细胞株HEPG-7402生长的体外试验；NS-398对肝细胞VEGF、MMP-9表达的调节；β-catenin、cyclin D1及c—myc在肝细胞癌中的表达.[编者按]     

黄芩素对人肝癌细胞株SMMC-7721体外迁移及侵袭的影响

  目的  通过观察黄芩素对人肝癌细胞株SMMC-7721体外迁移侵袭能力及Ezrin、MMP-9、VEGF表达的影响, 探讨黄芩素对人肝癌细胞株SMMC- 7721体外迁移侵袭的作用及其可能机制。  方法  体外培养SMMC-7721, 经黄芩素干预后用划痕愈合实验和侵袭小室实验分别检测黄芩素对SMMC-7721细胞迁移运动能力和侵袭能力的影响; RT-PCR和免疫细胞化学法检测黄芩素作用于SMMC-7721细胞48h后对Ezrin、MMP-9、VEGF mRNA和蛋白表达的影响。  结果  划痕愈合实验显示各浓度实验组划痕愈合宽度占原宽度的比例比对照组明显下降（P < 0.05）; 体外侵袭实验显示实验组穿过人工基底膜胶的细胞数明显减少（P < 0.05）; 实验组Ezrin、MMP-9、VEGF mRNA和蛋白表达均明显下调（P < 0.05）。  结论  黄芩素可能通过直接或间接下调Ezrin、MMP-9、VEGF mRNA和蛋白的表达而抑制人肝癌细胞株SMMC- 7721体外迁移侵袭, 传统中药黄芩可望为肝癌临床治疗提供新的安全、有效、价廉的治疗方法。      

罗格列酮对肝癌SMMC-7721细胞VEGF蛋白表达的影响

目的探讨过氧化物酶体增殖激活物受体γ( PPARγ) 配体罗格列酮对肝癌SMMC-7721细胞中VEGF表达的影响及其可能机制。方法经不同浓度罗格列酮（0、0.1、1、10、100μmol/L）分别作用SMMC-7721细胞24h、48h、72h后,采用Western印迹法检测细胞VEGF和PTEN、Akt1/2及P-Akt1蛋白表达的变化。结果罗格列酮可以显著抑制SMMC-7721细胞中VEGF蛋白表达水平（P<0.05）,呈时间和剂量依赖性;能上调细胞PTEN的表达,并呈时间和剂量依赖性（P<0.05）,但Akt_1/2及P-Akt₁的表达无明显改变（P>0.05）。结论罗格列酮可抑制SMMC-7721细胞中VEGF蛋白表达,该作用可能是与上调PTEN表达有关,但不是通过直接抑制PI3K/Akt信号转导途径来实现的。     

NS-398对肝癌SMMC-7721和BEL-7402细胞凋亡和survivin、PTEN表达调节作用的研究

目的:研究应用NS398对肝细胞癌细胞株进行药物干预,探讨NS398对肝细胞癌细胞增殖和凋亡的影响。方法:人肝细胞癌细胞株SMMC7721、BEL7402细胞常规培养。NS398取0、25、50、75、100μmol/L5个浓度组,每个浓度组选取24、48、72h三个作用时间点进行检测,观察NS398对各细胞株的作用。MTT法测定2种细胞株的增殖抑制情况,FCM检测对细胞周期和凋亡的影响,FCM定量检测COX2、survivin、PTEN的表达。结果:MTT法结果显示,NS398可以显著抑制SMMC7721、BEL7402细胞增殖。FCM检测结果显示,NS398分别使SMMC7721、BEL7402细胞G0/G1期比例显著降低;G2/M期细胞比例显著增高,S期细胞比例无明显变化,并引起了显著的细胞凋亡(P<0.001),并且呈时间依赖性和剂量依赖性。与对照组相比,NS398使COX2、survivin和PTEN蛋白表达显著下调并且呈时间和剂量依赖性关系(P<0.001)。结论:NS398通过诱导SMMC7721、BEL7402细胞株凋亡而抑制其增殖,可能部分通过下调survivin和PTEN途径实现的。     

miR-148a对肝癌细胞株侵袭和迁移的抑制作用及机制

背景与目的：原发性肝癌是肝细胞或肝内胆管上皮发生的恶性肿瘤,其复发和转移十分常见。本实验以慢病毒介导miR-148a,感染人肝癌SMMC-7721细胞,观察其对SMMC-7721细胞侵袭和迁移能力的影响。方法：选用SMMC-7721肝癌细胞株,进行miR-148a慢病毒载体的构建,筛选稳定表达miR-148a肝癌细胞株。RTPCR检测细胞中miR-148a的表达水平。划痕实验及Transwell侵袭实验检测细胞侵袭迁移能力。采用明胶酶谱法测定MMP-2、MMP-9的活性。蛋白质印迹法(Western blot)检测MMP-2、MMP-9和EMT相关蛋白(E-cadherin、vimentin)的表达情况。结果：RT-PCR结果显示,和对照组相比,LV-miR-148a肝癌细胞感染组表达miR-148a明显增高,体外侵袭实验细胞划痕实验显示过表达miR-148a后SMMC-7721的侵袭和迁移能力明显下降。明胶酶谱法结果显示过表达miR-148a的肝癌细胞,MMP-2和MMP-9降解明胶的能力下降(P<0.05)。过表达miR-148a同时能降低肝癌细胞SMMC-7721中vimentin、MMP-2和MMP-9蛋白的表达,但并未影响E-cadherin的表达。结论：miR-148a在体外能抑制肝癌细胞SMMC-7721的侵袭和迁移,其机制可能与下调MMP-2、MMP-9和vimentin的表达水平有关。     

GDF11对肝细胞癌SMMC-7721细胞增殖能力及顺铂敏感度的影响

目的 研究GDF11（growth differentiation factor 11）过表达对肝细胞癌SMMC-7721细胞体外增殖能力及顺铂敏感度的影响。方法 前期成功构建GDF11过表达的SMMC-7721细胞,同时以空载体感染细胞组及野生型细胞组为对照。CCK-8法检测细胞增殖能力,平板克隆形成实验检测细胞克隆形成能力。CCK-8法检测GDF11过表达对细胞顺铂药物敏感度的影响。结果 Western blot结果验证,已成功构建GDF11过表达的SMMC-7721细胞。GDF11过表达可明显抑制SMMC-7721细胞的体外增殖能力,在96、120及144 h时抑制作用最显著（P<0.05）,且实验组细胞较对照组克隆形成能力明显减弱（P<0.05）。GDF11过表达能够增强肝细胞癌SMMC-7721细胞对顺铂的敏感度,顺铂浓度取20 μg/ml及40 μg/ml时,与对照组相比差异有统计学意义（P<0.05）。结论 肝细胞癌SMMC-7721细胞过表达GDF11蛋白后,其体外增殖及克隆形成能力明显降低,对化疗药物顺铂的敏感度增强。     

沉默FOXQ1基因抑制肝细胞癌SMMC-7721细胞迁移侵袭能力

目的：探讨沉默叉头框蛋白Q1(forkhead box Q1,FOXQ1)基因后对肝细胞癌（hepatocellular carcinoma,HCC）SMMC-7721细胞迁移侵袭能力的影响及其机制。方法: 制备FOXQ1-shRNA、NC-shRNA重组慢病毒,将其感染到SMMC-7721细胞中;实验设干扰组、阴性对照组和空白组,用Transwell小室法检测细胞迁移、侵袭能力;利用qRT-PCR和Western blotting法检测SMMC-7721细胞中FOXQ1、MMP-2和MMP-9mRNA和蛋白的表达。结果: 随着肝癌SMMC-7721细胞的迁移侵袭能力的增强,FOXQ1的表达逐渐增加;干扰组较阴性对照组与空白组FOXQ1表达水平降低\[（0.34±0.03）vs（0.89±007）和（0.84±0.05）,P<0.05\];沉默FOXQ1基因后,SMMC-7721细胞的迁移侵袭能力显著下降\[(9.67±1.15) vs （25.67±208）和(27.33±2.52),P<0.05\],MMP-2与MMP-9表达水平下降\[MMP-2：(0.35±0.04) vs (0.61±0.05)和(065±008);MMP-9： (0.40±0.05) vs (0.73±0.07)和(0.77±0.06),均P<0.05\]。结论: 沉默FOXQ1基因的表达能够抑制肝癌SMMC-7721细胞的迁移、侵袭能力,其机制可能与MMP-2与MMP-9的表达下调有关。     

Survivin反义寡核苷酸对肝癌细胞增殖和凋亡的影响

目的：观察Survivin反义寡核苷酸对SMMC-7721细胞增殖、凋亡的影响.方法：设计合成特异性Survivin 反义寡核苷酸,转染肝癌SMMC-7721细胞,MTT法测定Survivin ASODN对细胞增殖抑制情况的影响,FCM法检测对细胞周期、凋亡及Survivin蛋白表达的影响.结果：Survivin ASODN可抑制SMMC-7721细胞的生长增殖,并呈浓度和时间依赖性.ASODN转染组可诱导SMMC-7721细胞凋亡（P＜0.01）,细胞周期阻滞于G2/M期（P＜0.05）.ASODN转染组Survivin蛋白表达水平显著降低（P＜0.01）.结论：Survivin ASODN能下调SMMC-7721细胞Survivin表达,并可抑制其增殖并诱导凋亡.     

蛇毒精氨酸酯酶Agkihpin抑制人肝癌SMMC-7721细胞株MRP1表达

  目的   探讨蛇毒精氨酸酯酶Agkihpin对人肝癌细胞株SMMC-7721中多药耐药相关蛋白1(multidrug resistance associated protein 1, MRP1)表达的影响, 并阐明Agkihpin抑制人肝癌SMMC-7721细胞活力的机制。   方法   目的: 方法: 采用不同浓度的Agkihpin处理SMMC-7721细胞72 h后, 应用免疫细胞化学、Western blot和RT-PCR等方法检测MRP1在SMMC-7721细胞中的转录和表达。   结果   不同浓度Agkihpin作用SMMC-7721细胞72 h后MRP1表达均降低, 显示Agkihpin可显著下调SMMC-7721细胞中MRP1转录和表达(P < 0.05), 并呈现出一定的浓度依赖效应。   结论   Agkibpin能抑制人低分化肝癌细胞株SMMC-7721中MRP1的表达, 并呈一定程度的浓度依赖效应, 提示Agkihpin在一定程度上可用于提高肝癌细胞对化疗药物的敏感性。      

Induction of G0/G1 cell cycle arrest in ovarian carcinoma cells by the anti-inflammatory drug NS-398, but not by COX-2-specific RNA interference

Cyclooxygenases, particularly COX-2, play an important role in tumor development and progression. We have previously shown that COX-2 expression is an independent prognostic factor in human ovarian carcinoma. In this study, we investigated the effects of the inhibition of COX isoforms by the NSAID NS-398 as well as by COX-isoform-specific RNA interference (RNAi) in the human ovarian carcinoma cell lines OVCAR-3 and SKOV-3. OVCAR-3 cells showed a constitutive expression of COX-1 and an induction of high levels of COX-2 and PGE(2) after stimulation with interleukin-1beta. In contrast, SKOV-3 cells were negative for both COX isoforms. In OVCAR-3 cells, PGE(2) production was inhibited by NS-398 in concentrations of 1 microM and by a COX-2-specific silencing RNA (siRNA), while a COX-1-specific siRNA did not have an effect. This suggests that COX-2 is the major source of PGE(2) in this cell line. To dissociate COX-2-specific and non-COX-2-specific effects on cell proliferation, a proliferation assay was performed after incubation of cells with NS-398 and COX siRNAs. NS-398 induced an inhibition of cell proliferation at concentrations of 50-500 microM, which are above the concentrations needed for the inhibition of PGE(2) production. This inhibitory effect was present in the COX-positive cell line OVCAR-3 as well as in the COX-negative cell line SKOV-3 and could not be reverted by addition of exogenous PGE(2). Neither COX-1- nor COX-2-specific siRNAs had an effect on cell proliferation of OVCAR-3 cells. Cell cycle analysis showed an increased accumulation of cells in the G0/G1 phase after treatment with NS-398, but not with COX siRNAs. These experiments suggest that NS-398 reduced cell proliferation in ovarian carcinoma cells by induction of G0/G1 cell cycle arrest independent of COX-2 inhibition. Our study shows that specific inhibition of COX isoforms by RNAi could be used to dissociate effects of NSAIDs. Furthermore, our results suggest that cell cycle arrest is one of the primary mechanisms responsible for the antiproliferative effects of NS-398 on ovarian carcinoma cells.     

NS-398逆转结肠癌细胞多药耐药性的作用

目的 观察COX-2选择性抑制剂NS-398对结肠癌耐药细胞HCT-8/Fu多药耐药的逆转作用及其对P-糖蛋白（P-glycoprotein, P-gp）、多药耐药相关蛋白（multi-drug resistance related protein, MRP）的调控,以初步探讨其作用机制。方法 （1）CCK-8法检测NS-398对HCT-8/Fu的毒性作用及对HCT-8/Fu细胞多药耐药（multi-drug resistance, MDR）的逆转作用;（2）将NS-398、5-Fu、NS-398+5-Fu分别作用于HCT-8/Fu 24 h,酶标仪检测Caspase -3活性、Hoechst33342染色观察药物诱导细胞凋亡情况;（3）0、10、20 μmol/L NS-398分别作用癌细胞24 h后ELISA法检测培养液中PGE2含量;0、20 μmol/L NS-398作用癌细胞24 h后,免疫细胞化学检测癌细胞P-gp、MRP的表达。结果 （1）10、20 μmol/LNS-398作用癌细胞24 h,抑制率分别为6%、8%,与各浓度5-Fu联用后,耐药逆转倍数分别为3.42、7.50,且呈剂量依赖性;（2）20 μmol/LNS-398+320 μg/ml 5-Fu组Caspase-3活性增加百分比为386.11%,较320μg/ml 5-Fu组的179.94%、20 μmol/LNS- 3 9 8 组的1 2 5 . 2 3%明显增高;Hoechst33342染色从形态学上也得出相一致的结论;（3）20 μmol/L NS-398作用24 h后,癌细胞P-gp、MRP表达较0μmol/L NS-398显著减少;同时在10、20 μmol/L NS-398作用24 h,细胞培养上清液中PGE2含量分别为189.50、151.25ng/L,较0 μmol/L NS-398时的340.13 ng/L明显下降。结论 COX-2选择性抑制剂NS-398对结肠癌耐药性有显著逆转作用,并呈剂量依赖性,其逆转机制可能是通过抑制P-gp、MRP的表达及抑制PGE2生成而发挥逆转作用的。     

Mechanism of growth inhibitory effects of cyclooxygenase-2 inhibitor-NS398 on cancer cells

Cyclooxygenase (COX)-2 appears to play an important role in gastrointestinal carcinogenesis, and COX-2 overexpression has been demonstrated both in esophageal adenocarcinomas and lymph nodes metastasis. The aim of our study was to investigate the mechanism of growth inhibitory effect of selective inhibition of COX-2 by NS-398 on human cancer cells. The esophageal cancer cell lines (EC9706) that express COX-2 permanently and hepatocellular carcinoma cell lines (SMMC7721) while no expression of COX-2 were studied. Two kinds of cell lines were treated with various concentrations of NS-398 (selective for COX-2 inhibition) at 0.01-0.1 mM for 24 h, 48 h and 72 h. Antiproliferation effect was measured by 3H-TdR incorporation. The cell apoptosis were determined by flow cytometry (FCM) and DNA fragmentation analysis. Survivin was detected by immunocytochemical technique. The growth inhibition could be induced by NS398 in a dose- and time-dependent manner in two kinds of cell lines. FCM analysis revealed a high sub-G1 cell peak in EC9706 group. Agarose electrophroesis showed marked apoptosis ladder pattern, but no apoptosis by NS-398 in SMMC7721. The difference of apoptosis percentage in EC9706 and SMMC7721 was (45.23 +/- 1.08)% and (3.05 +/- 0.15)% (p < 0.001). After 24 h incubation with NS-398 at concentration of 0.1 dmM, the expression of survivin was markedly reduced in EC9706, but not in SMMC7721. We conclude that the administration of a selective inhibitor of COX-2 significantly decreases cell growth in cancer cell lines by different mechanism. NS-398 could inhibit cell proliferation in cancer cells whether or no COX-2 expression. Nevertheless, apoptosis in the cancer cells expressing COX-2 protein increase more than those lacking COX-2.     

Effect of NS-398, a cyclooxygenase-2 selective inhibitor, on the cytotoxicity of cytotoxic T lymphocytes to ovarian carcinoma cells

Cyclooxygenase-2 (COX-2) is a key limited enzyme of prostaglandin (PG) synthesis and has been demonstrated to be overexpressed in cancer. N-[2-(cyclohexyloxy)-4-nitropheny]-methane sulfonamide (NS-398) is a special inhibitor of COX-2 and may suppress PGE2 release and promote immune response mechanism of cytotoxic T lymphocytes (CTLs). We aimed to investigate the effect of NS-398 on the PGE2 release, proliferation of ovarian carcinoma cell line CAOV3, and immune cytotoxicity of CTLs. CAOV3 cells were incubated with 0, 50, and 100 μmol/L NS-398 for 24, 48, and 72 h. Cell viability was determined by trypan blue staining. PGE₂ was measured using radioimmunoassay. CTLs were generated from peripheral blood mononuclear cells after stimulated by CAOV3 cells or CAOV3 cells treated with NS-398 when IL-2 existed. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was used to evaluate the cytotoxicity of CTLs. As expected, the amount, cell density, cellular volume, and growth speed of CAOV3 cells incubated with NS-398 were significantly decreased compared with control group. This difference became more obvious with an increase in the NS-398 concentration and incubation time. Similarly, PGE₂ released from CAOV3 cells treated with 50 and 100 μmol/L NS-398 was significantly decreased compared with control group (P?<?0.05). There was also significance in PGE₂ between the two groups treated with 50 and 100 μmol/L NS-398 (P?<?0.05). Compared with control group, the killing rates of CTLs to CAOV3 treated with 50 and 100 μmol/L NS-398 were significantly increased (P?<?0.05). However, there is no significant difference between them. Together, our results suggest that NS-398 could be useful in prevention and therapy of ovarian carcinoma.     

体外联合应用NS-398与5-FU抑制肝癌HepG2细胞生长的研究

目的研究体外联合应用选择性COX-2抑制剂NS-398与5-氟尿嘧啶(5-FU)对肝癌细胞生长的抑制作用.方法应用MTT法观察NS-398、5-FU及NS-398 5-FU对人肝癌细胞株HepG2的生长抑制作用;通过荧光显微镜、透射电镜、流式细胞仪研究NS-398、5-FU及NS-398 5-FU对HepG2的凋亡诱导作用.结果NS-398和5-FU对肝癌细胞HepG2的生长有显著抑制作用,NS-398和5-FU联合应用时抑制效应较单一应用更为明显.透射电镜、荧光显微镜观察和流式细胞仪检测显示,HepG2细胞经NS-398、5-FU及NS-398 5-FU处理后出现典型的细胞凋亡形态变化和Sub-G1峰.结论联合应用选择性COX-2抑制剂NS-398有增强5-FU抑制肝癌细胞生长的作用.     

Selective cyclooxygenase-2 inhibitors inhibit growth and induce apoptosis of bladder cancer

Selective COX-2 inhibitors such as celecoxib and NS-398 are being evaluated as chemopreventive and therapeutic agents for bladder and other cancers. We investigated the effects of these nonsteroidal anti-inflammatory agents on a panel of bladder cancer cell lines, and assessed their effects on anchorage-dependent and -independent growth, cell cycle, apoptosis and morphology. The human bladder cancer cell lines UM-UC-1, -3, and -6 were assayed for COX-2 expression by Western analysis using a monoclonal antibody to COX-2. UM-UC-1, -3, and -6 cells were grown in the presence of increasing concentrations of NS-398 and celecoxib, and cell growth was quantitated over 7 days by crystal violet elution. The cell lines were treated with NS-398 and celecoxib for 48 h and analyzed by flow cytometry with propidium iodide staining and Br-dUTP staining for apoptosis. Anchorage-independent growth was assessed using an agarose growth assay. Western analysis demonstrated that COX-2 expression in UM-UC-1, -6, and -3 was high, low, and undetectable, respectively. NS-398 and celecoxib produced dose-dependent growth inhibition of UM-UC-1 and -6. Both NS-398 and celecoxib also inhibited anchorage-dependent and -independent growth of UM-UC-3 in a dose-dependent fashion, despite the low basal expression of COX-2 in this cell line. Cell cycle analyses of UM-UC-1 and -6 revealed a 50% reduction in S-phase in the presence of 100 microM NS-398 whereas a smaller reduction in S-phase was noted in UM-UC-3 cells. Furthermore, treatment with 100 microM celecoxib resulted in significant apoptosis in all three cell lines, which was associated with downregulation of Bcl-2. COX-2 selective inhibitors NS-398 and celecoxib produced dose-dependent growth inhibition of bladder cancer cells associated with a significant reduction in S-phase. Induction of apoptosis in all three cell lines by celecoxib was associated with downregulation of Bcl-2. These changes occur independently of COX-2 expression levels suggesting the presence of a COX-2 independent pathway.     

A cyclooxygase-2 inhibitor NS-398-enhanced apoptosis of esophageal carcinoma cell EC9706 by adjusting expression of survivin and caspase-3

The aim of this study is to examine the effect and mechanism of a selective cyclooxygenase-2 (COX-2) inhibitor NS-398 on inducing apoptosis of esophageal cancer cells. After the treatment with NS-398 on esophageal carcinoma EC9706 cell, MTT assay was used to observe the inhibition of EC9706 cell growth and apoptosis was determined by electronic microscopy and flow cytometry. The expression of survivin and caspase-3 was examined using immunocytochemical technique. The dose of 0.01–0.1 mM NS398 showed the inhibitory effect on growth of EC9706 cell lines and induce apoptosis in a dose- and time-effective manner; moreover, NS-398 also downregulated the level of expression of survivin and elevated the expression of capase-3. NS-398 can induce apoptosis of the esophageal carcinoma EC9706 cells by means of adjusting expression of survivin and caspase-3.     

NS-398对人胃癌细胞系SGC-7901增殖、凋亡和COX-2表达的影响

目的 探讨环氧合酶-2(COX-2)抑制剂NS-398对人胃癌细胞系SGC-7901增殖、凋亡及COX-2表达的影响,并进一步探讨其作用的可能机制.方法 采用四甲基偶氮唑蓝(MTT)法检测NS-398对SGC -7901细胞的杀伤抑制作用;免疫细胞化学法检测SGC-7901细胞内COX-2的蛋白表达情况;ELISA法检测NS-398作用于SGC-7901细胞后PGE2释放水平;流式细胞仪检测SGC-7901细胞的凋亡情况.结果 NS-398对胃癌SGC-7901细胞具有较强的抑制作用,且这种抑制作用随浓度和时间的增加而增强,呈剂量-时间双效应关系(P＜0.05);不同浓度NS-398作用下的SGC-7901细胞中,COX-2的表达明显减弱,且呈剂量梯度下降(P＜ 0.05);NS-398可抑制PGE2释放,并且这种抑制作用呈剂量效应关系,与对照组相比差异有统计学意义(P＜ 0.05);NS-398作用于SGC-7901细胞48 h后,细胞凋亡率升高,且呈剂量效应(P＜0.05).结论 NS-398通过COX-2依赖途径抑制SGC-7901细胞增殖并促进其凋亡.     

Selective cyclooxygenase 2 inhibitor NS-398 induces apoptosis in myeloma cells via a Bcl-2 independent pathway

NS-398, a selective inhibitor of cyclooxygenase 2 (COX-2), has been reported to inhibit growth and induce apoptosis in several cancer cell lines that overexpress COX-2. However it has not been extensively studied in multiple myeloma (MM). Here, we studied the effects of COX-2 inhibitors on MM cell lines and primary myeloma patient cells. We investigated the effects of NS-398 on proliferation and apoptosis in three myeloma cell lines (PCM6, U266 and RPMI8226) and isolated CD138-positive cells from MM patients. Furthermore, the combined effects of NS-398 plus dexamethasone (Dex) or thalidomide (Thal) were investigated. All myeloma cell lines express COX-2. NS-398 inhibited growth and induced apoptosis in PCM6, RPMI8226 and CD138-positive MM cells in a time- and dose-dependent manner. At low concentrations (10 microM), NS-398 primarily induced growth arrest without affecting cell viability, but at higher concentrations (over 25 microM), apoptosis was induced. During the process of apoptosis, the number of Fas-positive cells increased. Downstream signals of Fas, such as caspase 8, 3 and 9, were also activated. On the other hand, protein levels of the Bcl-2 family did not change, although mitochondrial transmembrane potential ((Delta)(psi)m) was decreased. Combined incubation with Dex or Thal enhanced NS-398-induced growth inhibition and apoptosis in RPMI8226 cells. The combined effect of Dex was more potent than that of Thal. Our findings suggests that COX-2 plays an important role in regulation of apoptosis in myeloma cells, and COX-2 inhibitors might serve as an effective tool for future chemoprevention and/or treatment of myeloma.     

Apoptosis induction and cyclooxygenase-2 regulation in human colorectal adenoma and carcinoma cell lines by the cyclooxygenase-2-selective non-steroidal anti-inflammatory drug NS-398

We determined the effect of the highly selective cyclooxygenase-2 (COX-2) inhibitor NS-398 on proliferation, apoptosis and COX-2 regulation in 3 pre-malignant human colorectal adenoma cell lines (RG/C2, AA/C1, RR/C1) and compared its effect on 3 colorectal carcinoma cell lines (HT29, KS, JW2). COX-2 protein was expressed in each cell line derived from an adenoma, thus providing evidence that COX-2 is expressed in the tumour cells themselves at an early stage in human colorectal adenoma formation. NS-398 (20 to 100 microM for 96 h) induced apoptosis and inhibited the proliferation of the adenoma cell lines. Of the 3 carcinoma lines, only HT29 expressed COX-2 protein, yet each line was similarly sensitive to NS-398. There was a positive correlation between overall sensitivity of the cell lines (determined by the attached cell yield) and sensitivity to NS-398-induced apoptosis, suggesting that apoptosis is the dominant anti-proliferative effect of NS-398. Two of the 3 adenoma cell lines (RG/C2, AA/C1) were less sensitive than the carcinoma cell lines. NS-398 up-regulated COX-2 protein expression in the HT29 and adenoma cell lines. This was studied further in HT29 cultures, where treatment with NS-398 inhibited COX-2 activity, reducing prostaglandin E(2) secretion. Here, neither the increase in COX-2 protein expression nor the anti-proliferative and apoptosis-inducing effect of NS-398 was prevented by addition of exogenous prostaglandin E(2). Apoptosis appears to be the dominant anti-proliferative effect of NS-398 and, in COX-2 expressing cells, may be mechanistically linked to the observed induction of COX-2 protein expression upon treatment with NS-398.