Trichomonas vaginalis polyamine metabolism is linked to host cell adherence and cytotoxicity

Trichomonas vaginalis secretes putrescine that is readily detected in vaginal secretions. We wanted to examine the effect of decreased putrescine synthesis by inhibition of ornithine decarboxylase (ODC) on T. vaginalis. One reason is because inhibition of Tritrichomonas foetus ODC results in growth arrest, destruction of hydrogenosomes, and decreased amounts of hydrogenosomal enzymes. Treatment of T. vaginalis T016 with >/=20 mM 1,4-diamino-2-butanone (DAB) to inhibit ODC resulted in growth arrest, which was reversed by addition of exogenous putrescine. No similar reversal of growth arrest was achieved with the polyamines spermine or spermidine or with iron. Electron microscopic examination of control versus DAB-treated trichomonads did not reveal any adverse effects on the number and integrity of hydrogenosomes. Further, the adhesins AP65, AP51, and AP33 mediating binding to immortalized vaginal epithelial cells (VECs) share identity to enzymes of the hydrogenosome organelle, and there was no difference in amounts of adhesins between control versus DAB-treated T. vaginalis parasites. Likewise, similar patterns and extent of fluorescence were evident for the prominent AP65 adhesin. Surprisingly, DAB treatment increased by 4- to 20-fold above untreated trichomonads handled identically the level of adherence mediated by adhesins. Interestingly, the enhanced attachment to VECs was reversed by exogenous putrescine added to DAB-treated trichomonads. Equally noteworthy was that DAB-treated T. vaginalis with enhanced adherence did not possess the previously reported ability to kill host cells in a contact-dependent fashion mediated by cysteine proteinases, and total cysteine proteinase activity patterns were identical between control and DAB-treated trichomonads. Overall, these data suggest that polyamine metabolism and secreted putrescine are linked to host cell adherence and cytotoxicity.     

Inhibition of Trichomonas vaginalis motility by monoclonal antibodies is associated with reduced adherence to HeLa cell monolayers.

Adherence of trichomonads to host epithelial cells appears to be a critical step in the pathogenesis of trichomoniasis. We evaluated the effect of a panel of 10 monoclonal antibodies on attachment of [35S]methionine-radiolabeled Trichomonas vaginalis strains to HeLa cell monolayers. Of 10 monoclonal antibodies, 3 totally eliminated motility of PHS2J strain trichomonads and reduced their adherence to 48 to 60% of control values (P less than 0.001). However, none of the monoclonal antibodies affected motility or adherence of STD13 strain trichomonads. Although the antibodies all reacted with PHS2J trichomonads by immunofluorescence, there was no correlation between inhibition of adherence and findings on either immunofluorescence or radioimmunoprecipitation. Direct microscopic observations showed that incubation with the monoclonal antibodies did not cause cytolysis of T. vaginalis. In quantitative cultures there was no difference in the number of colonies produced by parasites that had been incubated with antibodies that inhibited or had no effect on adherence. We conclude that our monoclonal antibodies reduced adherence not by cytotoxic effects or by competing for specific sites mediating adherence of the protozoa, but by inhibiting motility of T. vaginalis.     

Specific parasitism of purified vaginal epithelial cells by Trichomonas vaginalis.

Human vaginal epithelial cells (VECs) from vaginal swabs obtained from normal women or from patients with trichomoniasis were purified, and VEC parasitism by Trichomonas vaginalis was examined. Trichomonads bound equally well to live or dead VECs, and up to 20% of VECs were parasitized. Trichomonal cytadherence of human VECs was time, temperature, and pH dependent. Saturation binding levels of live trichomonads to VECs gave approximately 2 organisms adherent to parasitized VEC. No differences in cytadherence levels were detected by different isolates to VECs from the same patient compared with adherence to VECs from normal individuals. Trypsinized, live T. vaginalis organisms failed to recognize VECs. A ligand assay identified four adhesin candidates, and only organisms without a prominent immunogen on the surface (negative phenotype) cytadhered to VECs and synthesized the adhesins, confirming the results of a recently published report by us on adherence to HeLa cell monolayers (J. F. Alderete and G. E. Garza, Infect. Immun. 56:28-33, 1988). These data show the ability of T. vaginalis to parasitize human vaginal epithelial cells in a specific receptor-ligand manner.     

Specific nature of Trichomonas vaginalis parasitism of host cell surfaces.

The adherence of Trichomonas vaginalis NYH 286 to host cells was evaluated by using monolayer cultures of HeLa and HEp-2 epithelial cells and human fibroblast cell lines. Saturation of sites on HeLa cells was achieved, yielding a maximal T. vaginalis NYH 286-to-cell ratio of two. The ability of radiolabeled NYH 286 to compete with unlabeled trichomonads for attachment and the time, temperature, and pH-dependent nature of host cell parasitism reinforced the idea of specific parasite-cell associations. Other trichomonal isolates (JH31A, RU375, and JHHR) were also found to adhere to cell monolayers, albeit to different degrees, and all isolates produced maximal contact-dependent HeLa cell cytotoxicity. The avirulent trichomonad, Trichomonas tenax, did not adhere to cell monolayers and did not cause host cell damage. Interestingly, parasite cytadherence was greater with HeLa and HEp-2 epithelial cells than with fibroblast cells. In addition, cytotoxicity with fibroblast cells never exceeded 20% of the level of cell killing observed for epithelial cells. Elucidation of properties of the pathogenic human trichomonads that allowed for host cell surface parasitism was also attempted. Treatment of motile T. vaginalis NYH 286 with trypsin diminished cell parasitism. Incubation of trypsinized organisms in growth medium allowed for regeneration of trichomonal adherence, and cycloheximide inhibited the regeneration of attachment. Organisms poisoned with metronidazole or iodoacetate failed to attach to host cells, and adherent trichomonads exposed to metronidazole or iodoacetate were readily released from parasitized cells. Coincubation experiments with polycationic proteins and sugars and pretreatment of parasites or cells with neuraminidase or periodate had no effect on host cell parasitism. Colchicine and cytochalasin B, however, did produce some inhibition of adherence to HeLa cells. The data suggest that metabolizing T. vaginalis adheres to host cells via parasite surface proteins in a specific receptor-ligand fashion. Furthermore, parasitism of epithelial cells appears to render this cell type more susceptible than fibroblast cell types to contact-dependent cytotoxicity.     

Trichomonas vaginalis surface proteinase activity is necessary for parasite adherence to epithelial cells.

The role of cysteine proteinases in adherence of Trichomonas vaginalis NYH 286 to HeLa and human vaginal epithelial cells was evaluated. Only pretreatment of trichomonads, but not epithelial cells, with N-alpha-p-tosyl-L-lysine chloromethyl ketone (TLCK), an inhibitor of trichomonad cysteine proteinases, greatly diminished the ability of T. vaginalis to recognize and bind to epithelial cells. Leupeptin and L-1-tosylamide-2-phenylethyl chloromethyl ketone, other cysteine proteinase inhibitors, also decreased T. vaginalis cytadherence. Parasites incubated with TLCK and washed extensively still did not adhere to cells at levels equal to those seen for control trichomonads treated with phosphate-buffered saline or culture medium alone. Exposure of TLCK-treated organisms with other cysteine proteinases restored cytadherence levels, indicating that proteinase action on the parasite surface is prerequisite for host cell attachment. Concentrations of TLCK which inhibited cytadherence did not alter the metabolism of T. vaginalis, as determined by metabolic labeling of trichomonad proteins; the protein patterns of T. vaginalis in the presence and absence of TLCK were identical. Kinetics of TLCK-mediated inhibition of cytadherence of other T. vaginalis isolates with different levels of epithelial-cell parasitism were similar to the concentration-dependent inhibition seen for isolate NYH 286. Incubation of TLCK-treated, washed organisms in growth medium resulted in regeneration of adherence. Finally, treatment of T. vaginalis organisms with proteinase inhibitors for abrogation of cytadherence effectively rendered the trichomonads unable to kill host cells, which is consistent with the contact-dependent nature of host cytotoxicity. These data show for the first time the involvement of T. vaginalis cysteine proteinases in parasite attachment to human epithelial cells. These results have implications for future pharmacologic intervention at a key step in infection.     

Identification and properties of Trichomonas vaginalis proteins involved in cytadherence.

Trichomonas vaginalis NYH286 surface proteins which are candidates for mediating parasite cytadherence (adhesins) were identified. At least four trichomonad protein ligands ranging in relative molecular mass from 65 to less than or equal to 21 kilodaltons were found to selectively bind to chemically stabilized HeLa cells. The proteins were present on the surfaces of 10 different isolates of T. vaginalis examined; however, the nonpathogenic trichomonad T. tenax did not possess similar HeLa cell-binding proteins under identical experimental conditions, suggesting that these proteins are unique to the pathogenic human trichomonads. The surface nature of the candidate adhesins was confirmed by the ability of the proteins on intact, live organisms to be radioiodinated and to be removed with trypsin treatment. Rabbit antiserum (immunoglobulin G fraction) generated against adhesin proteins electroeluted from acrylamide preparations inhibited cytadherence compared with control immunoglobulin G. An adherence-negative subpopulation of T. vaginalis NYH286 organisms was also isolated. These nonadherent trichomonads did not synthesize the adhesin proteins. Interestingly, absence of adhesins from these parasites paralleled expression of a major immunogen known to undergo phenotypic variation. Revertant organisms derived from the adherence-minus subpopulation synthesized the adhesins and attached to HeLa cells. The emergence of revertant adherent T. vaginalis organisms also corresponded with the appearance of parasites which were without the major immunogen on their surface. Finally, it was determined that only those parasites lacking the major surface immunogen were capable of adherence and toxicity to HeLa cells.     

Surface properties and in vitro cytopathic effect of various strains of Trichomonas vaginalis

The in vitro cytopathic effect of four strains of Trichomonas vaginalis on cultured epithelial monolayers was analyzed through electrophysiology and electron microscopy. Interaction of trichomonads of two virulent strains (GT-10 and GT-13) with cultured MDCK cell monolayers mounted in Ussing chambers produced a rapid decrease in transepithelial resistance to less than 30% of control values after only 15 min. By 30 min the electrical resistance was practically abolished by the virulent parasites. In contrast, of two attenuated strains of trichomonads (GT-3 and GT-7) analyzed under similar conditions, GT-3 trophozoites required 180 min to reduce transepithelial resistance to 9% of control values, while monolayers in contact with GT-7 parasites still showed 28% of control values at this time of incubation. Sequential scanning electron microscopy confirmed the much faster and widespread cytopathic effect of virulent parasites. In contrast, the slow lytic process produced by attenuated trophozoites was reduced to focal areas of direct contact with epithelial cells. Another difference was found by measurement of the surface charge of the four strains of T. vaginalis by means of cell microelectrophoresis. While the two virulent strains showed a negative surface charge, the two attenuated strains had no detectable surface charge at neutral pH. When parasites were incubated with cationized ferritin and studied with transmission electron microscopy the surface of virulent trichomonads appeared heavily labeled, whereas the surface of attenuated parasites had only sparse and irregular ferritin binding.     

尿道致病性大肠埃希菌感染对人膀胱上皮细胞基因表达谱的影响

目的 研究尿道致病性大肠埃希菌(UPEC)菌株132与人膀胱上皮EJ细胞的相互作用,分析该菌株感染对EJ细胞基因表达谱的改变.方法 UPEC132感染EJ细胞,用倒置显微镜观察细菌与细胞的黏附,计算黏附率,并通过激光共聚焦显微镜观察UPEC132对细胞的侵袭.感染UPEC132的EJ细胞与未经细菌感染的细胞提取总RNA,用人类全基因组寡核苷酸微阵列芯片分析差异表达基因,并采用RT-PCR对基因芯片数据进行验证.结果 UPEC132能够黏附于EJ细胞表面,黏附率为(73.20±5.26)%;激光共聚焦显微镜观察发现部分细菌位于细胞内部,证实该菌对EJ细胞具有侵袭性.UPEC132感染后的EJ细胞与未经感染的细胞相比,共有28个基因上调,1个基因下调,主要涉及细胞增殖、炎症反应、细胞凋亡等相关基因.结论 UPEC与尿路上皮细胞的相互作用激活宿主细胞内部多种应答反应与信号转导途径,本研究为深入探索UPEC致病机制奠定基础.     

人类免疫缺陷病毒-1型感染对U937前单核细胞基因表达的影响

目的：研究人类免疫缺陷病毒-1型(HIV-1) 急性感染对U937前单核细胞基因表达的影响，探索AIDS的病理机制。方法:应用基因芯片技术分析HIV-1感染2-3 d后U937前单核细胞的550个RNA序列的表达水平,并用半定量RT-PCR加以验证。结果:感染HIV-1 后2-3 d的U937细胞有38 个基因受到不同的调节：26个基因被下调，12个基因上调。这些基因编码着功能各异的宿主 蛋白，这些蛋白质涉及不同的细胞内反应过程，包括受体介导的信号转换、亚细胞信号转导 、 凋亡、转录调节和化学趋向等。结论:HIV-1感染能引起U937前单核细胞 许多基因表达发生改变。     

Binding of fibronectin by Trichomonas vaginalis is influenced by iron and calcium

We have reported that Trichomonas vaginalis, the causative agent of the most common, non-viral sexually transmitted disease, bound to cover slips coated with fibronectin (FN) (Crouch & Alderete, Microbiol 1999 145: 2835-43). In this study, we extend that observation by showing that FN binding is specific, and we present data on the requirements of FN binding by T. vaginalis. Immunofluorescence and immuno-gold labelling readily detected FN throughout the trichomonal surface. Parasites bound to(125)I-labelled FN in a time- and concentration-dependent fashion. In the absence of protease inhibitor, iodinated FN was released from the trichomonad surface. Unlabelled FN specifically competed for binding in a concentration-dependent fashion with the(125)I-labelled FN. Interestingly, the amount of FN bound by T. vaginalis organisms was dependent on iron. High-iron-grown trichomonads acquired lower numbers of molecules but with 10-fold higher affinity than low-iron-grown organisms. Further, we show that for iron-replete organisms, calcium (Ca(2+)) at physiological levels increased amounts of bound FN. The increase in binding was rapid, occurring within 5 min of Ca(2+)addition, and required de novo protein synthesis. Co-incubation of live parasites with Ca(2+)in the presence of FN was necessary to increase the amount of FN bound. Treatment of trichomonads with okadaic acid, but not other phosphatase inhibitors, resulted in a 50% decrease in binding of FN, regardless of the presence of Ca(2+), suggesting a role for phosphatase in FN association. These results indicate that depending on the iron status of T. vaginalis organisms in vivo, Ca(2+)may influence trichomonad recognition and binding to FN during host parasitism.     

Contact-dependent cytopathogenic mechanisms of Trichomonas vaginalis.

The cytopathogenic mechanisms of Trichomonas vaginalis have been debated since the 1940s. We examined the following three proposed pathogenic mechanisms: contact-dependent extracellular killing, cytophagocytosis, and extracellular cytotoxins. Serial observations of Chinese hamster ovary (CHO) cell monolayers exposed to trichomonads revealed that (i) trichomonads form clumps, (ii) the clumps adhere to cells in culture, and (iii) monolayer destruction occurs only in areas of contact with T. vaginalis. Kinetic analysis of target cell killing by trichomonads revealed that the probability of CHO cell death was related to the probability of contact with T. vaginalis, supporting the observation by microscopy that trichomonads kill cells only by direct contact. Simultaneous studies of 111indium oxine label release from CHO cells and trypan blue dye exclusion demonstrated that T. vaginalis kills target cells without phagocytosis. Filtrates of trichomonad cultures or from media in which trichomonads were killing CHO cells had no effect on CHO cell monolayers, indicating that trichomonads do not kill cells by a cell-free or secreted cytotoxin. The microfilament inhibitor cytochalasin D (10 micrograms/ml) inhibited trichomonad killing of CHO cell monolayers by 80% (P less than 0.0001). In contrast, the microtubule inhibitor vinblastine (10(-6) M) caused only 17% inhibition of trichomonad destruction of CHO cell monolayers (P less than 0.020), whereas colchicine (10(-6) M) had no effect. T. vaginalis kills target cells by direct contact without phagocytosis. This event requires intact trichomonad microfilament function; microtubule function appears not to be essential.     

Iron Modulates Phenotypic Variation and Phosphorylation of P270 in Double-Stranded RNA Virus-Infected Trichomonas vaginalis

Trichomonas vaginalis infected with a double-stranded RNA virus undergoes phenotypic variation on the basis of surface versus cytoplasmic expression of the immunogenic protein P270. Examination of batch cultures by flow cytofluorometry with monoclonal antibody (MAb) to P270 yields both fluorescent and nonfluorescent trichomonads. Greater numbers and intensity of fluorescent organisms with surface P270 reactive with MAb were evident in parasites grown in medium depleted of iron. Placement of iron-limited organisms in medium supplemented with iron gave increased numbers of nonfluorescent trichomonads. Purified subpopulations of trichomonads with and without surface P270 obtained by fluorescence-activated cell sorting reverted to nonfluorescent and fluorescent phenotypes when placed in high- and low-iron media, respectively. No similar regulation by iron of P270 was evident among virus-negative T. vaginalis isolates or virus-negative progeny trichomonads derived from virus-infected isolates. Equal amounts of P270 were detectable by MAb on immunoblots of total proteins from identical numbers of parasites grown in low- and high-iron media. Finally, P270 was found to be highly phosphorylated in high-iron parasites. Iron, therefore, plays a role in modulating surface localization of P270 in virus-harboring parasites.     

Gene expression in Porphyromonas gingivalis after contact with human epithelial cells

Porphyromonas gingivalis, a gram-negative oral anaerobe, is strongly associated with adult periodontitis. The adherence of the organism to host epithelium signals changes in both cell types as bacteria initiate infection and colonization and epithelial cells rally their defenses. We hypothesized that the expression of a defined set of P. gingivalis genes would be consistently up-regulated during infection of HEp-2 human epithelial cells. P. gingivalis genome microarrays were used to compare the gene expression profiles of bacteria that adhered to HEp-2 cells and bacteria that were incubated alone. Genes whose expression was temporally up-regulated included those involved in the oxidative stress response and those encoding heat shock proteins that are essential to maintaining cell viability under adverse conditions. The results suggest that contact with epithelial cells induces in P. gingivalis stress-responsive pathways that promote the survival of the bacterium.     

去卵巢和雌激素替代治疗对心肌细胞基因表达谱的影响

目的：本实验通过高通量的cDNA微阵列技术，研究去卵巢和雌激素替代治疗对心肌细胞基因表达谱的影响，寻找雌激素的靶基因。方法:用 1 400 个基因构建的cDNA微阵列检测假手术组（Ⅰ）、去卵巢组（Ⅱ，去势组）和雌激素替代治疗组（Ⅲ，替代组）3组SD雌鼠心肌组织的基因表达差异,随机选2个基因用半定量RT-PCR验证检测结果。结果:假手术组和去势组共检出心肌差异表达的基因177个，其中去卵巢导致上调的基因91个，下调的基因86个；去势组和替代组共检出心肌差异表达的基因164个，其中雌激素替代治疗后导致上调的基因113个，下调的基因54个。Ⅰ/Ⅱ和Ⅲ/Ⅱ比较，相同的差异表达基因54个，雌激素明显影响心肌膜通道和载体（18个）、细胞受体（9个）、信号转导相关基因（7个）和细胞代谢（6个）的mRNA水平。而大部分基因（45个）是在去势组表达下调，在雌激素替代组表达上调。RT-PCR实验证实了cDNA微阵列结果 。结论：长期雌激素替代治疗明显影响心肌细胞膜通道和载体、信号转导、细胞受体和细胞代谢等相关基因的表达。长期雌激素替代治疗可通过增加Na+,K+-ATPase和Na+/H+交换蛋白的基因表达，稳定心肌细胞内Na+和K+的浓度。雌激素还可抑制多巴胺受体基因的表达，预防心肌肥大、充血性心衰等心脏疾病的发生。     

Acquisition of alpha 1-Antitrypsin by a pathogenic strain of Trichomonas vaginalis.

The interaction of alpha 1-Antitrypsin, the major serine protease inhibitor in plasma, with pathogenic Trichomonas vaginalis and the acquisition by trichomonads of this host protein from normal human plasma were investigated. alpha 1-Antitrypsin acquired by intact parasites could not be removed by repeated washings in phosphate-buffered saline. Saturation kinetics were observed after incubation of glutaraldehyde-fixed organisms with 125I-labeled alpha 1-antitrypsin. Evidence suggesting that specific parasite membrane sites were responsible for trichomonal acquisition of alpha 1-antitrypsin was obtained through competitive binding experiments using purified preparations of homologous versus heterologous plasma proteins. No evidence of degradation of bound antitrypsin by live parasites was observed. The avid binding of alpha 1-antitrypsin by pathogenic T. vaginalis after incubation in normal human plasma was demonstrated by using sensitive electrophoretic and immunodetection techniques. Radioimmunoprecipitation of intrinsically labeled, detergent-solubilized extracts of T. vaginalis incubated with monospecific antisera against alpha 1-antitrypsin and other human plasma proteins revealed the inability of parasites to biosynthesize any substance cross-reactive with host plasma proteins. Finally, T. vaginalis organisms pretreated with alpha 1-antitrypsin inhibited trypsin caseinase activity in an in vitro assay. The implications of these observations are discussed.     

Differential effects of epinephrine, norepinephrine, and indole on Escherichia coli O157:H7 chemotaxis, colonization, and gene expression

During infection in the gastrointestinal tract, enterohemorrhagic Escherichia coli (EHEC) O157:H7 is exposed to a wide range of signaling molecules, including the eukaryotic hormones epinephrine and norepinephrine, and bacterial signal molecules such as indole. Since these signaling molecules have been shown to be involved in the regulation of phenotypes such as motility and virulence that are crucial for EHEC infections, we hypothesized that these molecules also govern the initial recognition of the large intestine environment and attachment to the host cell surface. Here, we report that, compared to indole, epinephrine and norepinephrine exert divergent effects on EHEC chemotaxis, motility, biofilm formation, gene expression, and colonization of HeLa cells. Using a novel two-fluorophore chemotaxis assay, it was found that EHEC is attracted to epinephrine and norepinephrine while it is repelled by indole. In addition, epinephrine and norepinephrine also increased EHEC motility and biofilm formation while indole attenuated these phenotypes. DNA microarray analysis of surface-associated EHEC indicated that epinephrine/norepinephrine up-regulated the expression of genes involved in surface colonization and virulence while exposure to indole decreased their expression. The gene expression data also suggested that autoinducer 2 uptake was repressed upon exposure to epinephrine/norepinephrine but not indole. In vitro adherence experiments confirmed that epinephrine and norepinephrine increased attachment to epithelial cells while indole decreased adherence. Taken together, these results suggest that epinephrine and norepinephrine increase EHEC infection while indole attenuates the process.     

Trichomonas vaginalis NYH286 phenotypic variation may be coordinated for a repertoire of trichomonad surface immunogens.

Trichomonas vaginalis isolate NYH286 was fractionated with immunoglobulin G of sera from patients with trichomoniasis. Subpopulations of trichomonads with phenotypes of either patient serum-immunoglobulin G reactive (PS+) or nonreactive (PS-) were obtained. Flow cytofluorometry of PS+ and PS- subpopulations with a monoclonal antibody called C20A3 which reacts with a high-molecular-weight immunogen of T. vaginalis gave corresponding fluorescent (positive) and nonfluorescent (negative) phenotypes. No relationship was seen between PS+ and PS- phenotypes and binding of soybean agglutinin, wheat germ agglutinin, and concanavalin A, showing that PS- organisms still possessed carbohydrate moieties on their surfaces based on lectin binding. Phenotypic variation among the PS+ and PS- trichomonads was observed during in vitro growth. A positive-to-negative phenotype shift was also recorded for parasites obtained from lesions of mice subcutaneously infected with PS+ trichomonads. The involvement of surface proteins in the differential PS+ and PS- reactions was supported by soluble antigen and whole cell radioimmunoprecipitation assays. Finally, enhanced parasitism and killing of HeLa cells in monolayer cultures were observed for PS- subpopulations as compared with PS+ counterparts. The data support the idea that phenotypic variation for T. vaginalis may be coordinated for a repertoire of trichomonad immunogens and that such membrane dynamics influence expression of virulence determinants for these sexually transmitted disease agents.     

Lovastatin对肝癌HepG2细胞作用后基因差异表达的初步研究

目的： 用cDNA芯片观察lovastatin作用前后HepG2细胞的差异表达基因。 方法： 20 μmol/L的lovastatin作用于HepG2细胞18 h，各提取实验组与对照组细胞总RNA，用cDNA直接标记法制备探针，进行杂交，杂交信号经扫描后，用软件分析基因表达情况。应用RT-PCR验证部分差异表达基因。 结果： Lovastatin作用后表达上调的基因有30个，表达下调的基因有11个，涉及信号转导、肿瘤免疫、细胞周期等方面，RT-PCR结果符合基因芯片结果。 结论： 用基因芯片筛选出的lovastatin作用后的肝癌细胞差异表达基因为深入研究他汀类药物的抗肿瘤机制提供重要的理论依据。