Indoleamine 2,3-dioxygenase: As a potential prognostic marker and immunotherapeutic target for hepatocellular carcinoma

Tumor cells induce an immunosuppressive microen-vironment which leads towards tumor immune escape. Understanding the intricacy of immunomodulation by tumor cells is essential for immunotherapy. Indoleamine 2,3-dioxygenase(IDO) is an immunosuppressive enzyme which mediates tumor immune escape in various cancers including hepatocellular carcinoma(HCC). IDO up-regulation in HCC may lead to recruitment of regulatory T-cells into tumor microenvironment and therefore inhibit local immune responses and promote metastasis. HCC associated fibroblasts stimulate natural killer cells dysfunction through prostaglandin E2 and subsequently IDO promotes favorable condition for tumor metastasis. IDO up-regulation induces immuno-suppression and may enhance the risk of hepatitis C virus and hepatitis B virus induced HCC. Therefore, IDO inhibitors as adjuvant therapeutic agents may have clinical implications in HCC. This review proposes future prospects of IDO not only as a therapeutic target but also as a prognostic marker for HCC.

Inhibition of allogeneic T-cell response by Kupffer cells expressing indoleamine 2,3-dioxygenase

AIM:To explore the possibility and mechanism of inhibiting allogeneic T-cell responses by Kupffer cells (KC)pretreated with interferon-γ(IFN-γ)in vitro. METHODS:The expressions of indoleamine 2,3-dioxygenase(IDO)mRNA and FasL mRNA in KC pretreated with IFN-γwere studied with real-time polymerase chain reaction(PCR).The catabolism of tryptophan by IDO from KC was analyzed by high performance liquid chromatography.Allogeneic T-cell response was used to confirm the inhibition of KC in vitro.The proliferation of lymphocytes was detected using[ 3 H]thymidine incorporation.Cell cycle and lymphocyte apoptosis were evaluated by flow cytometric assay. RESULTS:Real-time PCR revealed IDO mRNA and FasL mRNA expressions in KC pretreated with IFN-γ,and IDO catabolic effect was confirmed by a decrease in tryptophan and increase in kynurenine concentration. KC expressing IDO and FasL in BABL/c mice acquired the ability to suppress the proliferation of T-cells from C57BL/6,which could be blocked by addition of 1-methyl-tryptophan and anti-FasL antibody.KC expressing IDO could induce allogeneic T-cell apoptosisCONCLUSION:In addition to Fas/FasL pathway,IDO may be another mechanism for KC to induce immune tolerance.

Review of 10 years of research on breast cancer patients:Focus on indoleamine 2,3-dioxygenase

Therapeutic manipulation of the immune system in cancer has been an extensive area of research in the field of oncoimmunology.Immunosuppression regulates antitumour immune responses.An immunosuppressive enzyme,indoleamine 2,3-dioxygenase(IDO)mediates tumour immune escape in various malignancies including breast cancer.IDO upregulation in breast cancer cells may lead to the recruitment of regulatory T(T-regs)cells into the tumour microenvironment,thus inhibiting local immune responses and promoting metastasis.Immunosuppression induced by myeloid derived suppressor cells activated in an IDOdependent manner may enhance the possibility of immune evasion in breast cancer.IDO overexpression has independent prognostic significance in a subtype of breast cancer of emerging interest,basal-like breast carcinoma.IDO inhibitors as adjuvant therapeutic agents may have clinical implications in breast cancer.This review proposes future prospects of IDO not only as a therapeutic target but also as a valuable prognostic marker for breast cancer.

Mesenchymal-epithelial Transition Factor Regulates Monocyte Function during Mycobacterial Infection via Indoleamine 2,3-dioxygenase

Objective Mycobacterium tuberculosis(Mtb),the causative agent of tuberculosis(TB),causes an estimated 1.6 million human deaths annually,but the pathogenesis of TB remains unclear.Immunity plays a critical role in the onset and outcome of TB.This study aimed to uncover the roles of innate and adaptive immunity in TB.Methods The gene expression profiles generated by RNA sequencing from human peripheral blood mononuclear cells(PBMCs)stimulated with or without Mtb strain H37Rv antigens were analyzed.A total of 973 differentially expressed mRNAs were identified.Results The differentially expressed genes were enriched in innate immunity signaling functions.The mesenchymal-epithelial transition factor(MET)gene was significantly upregulated in CD14^(+)monocytes.A MET inhibitor improved the uptake of the BCG strain by monocytes and macrophages as well as inhibited the expression of indoleamine 2,3-dioxygenase(IDO).The expression of IDO was increased in PBMCs stimulated with Mtb antigens,and the IDO inhibitor promoted the expression of CD40,CD83,and CD86.Conclusion Our results might provide clues regarding the immunomodulatory mechanisms used by Mtb to evade the host defense system.

Expression of indoleamine 2,3-dioxygenase in a murine model of Aspergillus fumigatus keratitis

AIM： To observe the presence and expression of indoleamine 2,3-dioxygenase（IDO） during the corneal immunity to Aspergillus fumigatus（A. fumigatus） in the murine models.·METHODS： The murine model of fungal keratitis was established by smearing with colonies of A. fumigatus after scraping central epithelium of cornea and covering with contact lenses in C57BL/6 mice. The mice were randomly divided into control group, sham group and A.fumigatus keratitis group. The cornea was monitored daily using a slit lamp and recorded disease score after infection. Corneal lesion was detected by immunofluorescence staining. IDO m RNA and protein were also detected by quantitative reverse transcription-polymerase chain reaction（q RT-PCR） and Western blot.· RESULTS： The disease score and slit lamp photography indicated that disease severity was consistent with corneal inflammation in the murine models, and the disease scores in A. fumigatus keratitis group were obviously higher than those in the sham group. By immunofluorescence staining, IDO was mainly localized in corneal epithelium and stroma in the murine corneal tissues with A. fumigatus keratitis. Compared with the sham group, IDO m RNA expression was significantly enhanced in corneal epithelium infected by A. fumigatus. Furthermore, IDO protein expression detected by Western blot was in accord with transcript levels of IDO m RNA measured by q RT-PCR. IDO protein expression was enhanced after A. fumigatus infection compared with the sham group.·CONCLUSION： IDO is detected in corneal epithelium and stroma locally, which indicates IDO takes part in the pathogenesis of A. fumigatus keratitis and plays a key role in immune regulation at the early stage.

Molecular Cloning and Characterization of Porcine Indoleamine 2,3-Dioxygenase and Its Expression in Various Tissues

In order to confirm the existence of indoleamine 2,3-dioxygenase(IDO) gene in swine,and to clone the novel gene followed by the molecule structure properties and expression pattern analysis,the porcine mRNA sequences homologous to human IDO were obtained from GenBank database by bioinformatics method.By using RT-PCR,the IDO gene was cloned from porcine endothelial cell line and the accuracy of the nucleic acid sequence was confirmed,and the expression pattern of the gene was detected.The three-dimensional structure model of porcine IDO was built referring to the tertiary structure of human IDO using biological sequence analysis software and database.The results showed that the porcine IDO was identified by sequencing.The nucleotide sequences were confirmed as a novel gene after submitted to Genbank.Porcine IDO was expressed in the lung,thymus,epididymis and anterior chamber with a basic level,however in peripheral blood mononuclear cells(PBMCs) the IDO gene was highly expressed.The three-dimensional structure model of porcine IDO was similar to that of human IDO.It was suggested that identification of the structure information of porcine IDO is essential to further investigate the immunologic function of the gene.Study of IDO on NK cells-mediated xenograft rejection will be a novel therapeutic target for the development of xenotransplantation.

Relationship of Abortion and the Expression of Indoleamine 2,3- dioxygenase (IDO) in Villus and Syncytiotrophoblasts

Objective To study the relationship of abortion and the expression of indoleamine 2, 3- dioxygenase （IDO） in villus and syncytiotrophoblast in vitro. Methods RT-PCR was applied to analyze the mRNA transcription of lDO in villus of normal pregnancy and inevitable abortion and JAR cells as well. Immunohistochemistry was applied to analyze the expression of IDO protein in villus. Western blot was applied to determinate the expression of IDO protein on cultured syncytiotrophoblast. Highperformance liquid chromatography was applied to determinate whether there was kynurenine in cell culture medium of syncytiotrophoblast. Results The expression of IDO mRNA and protein in villus of inevitable abortion was lower than that of normal pregnancy; IDO mRNA did not express in JAR cells. IDO protein expressed on cultured syncytiotrophoblast, and there was kynurenine in cell culture medium of syncytiotrophoblast. Conclusion Appropriate expression of IDO in villus is necessary.for maintenance of normal pregnancy and an active IDO protein expresses in syncytiotrophoblast.

Myricetin inhibits interferon-γ-induced programmed death ligand-1 and indoleamine 2,3-dioxygenase 1 expression in lung cancer cells

OBJECTIVE Programmed death ligand-1(PD-L1)and indoleamine 2,3-dioxygenase 1(IDO1)are immune checkpoints which can be induced by interferon-γ(IFN-γ)in the tumor microenvironment,leading to immune escape of tumors.Myricetin(MY)is a flavonoid distributed in many edible and medicinal plants.The aim of this study is to clarify the effect and the mechanism of MY on inhibiting IFN-γ-induced PD-L1 and IDO1 in lung cancer cells.METHODS Expressions of PD-L1 and major histocompatibility complex-I(MHC-I)were evaluated by flow cytometry and Western blotting,and the expression of IDO1 was measured by Western blotting.qRT-PCR was used to detect their mRNA levels.The function of T cells was evaluated using a co-culture system consist of lung cancer cells and the Jurkat-PD-1 T cell line that overexpressing PD-1.Molecular docking analysis,Western blotting and immunofluorescence were used for mechanism study.RESULTS MY potently inhibited IFN-γ-induced PD-L1 and IDO1 expression in human lung cancer cells,while didn't show obvious effect on the expression of MHC-I.In addition,MY restored the survival,proliferation,CD69 expression and interleukin-2(IL-2)secretion of Jurkat-PD-1 T cells suppressed by IFN-γ-treated lung cancer cells in the co-culture system.Mechanistically,IFN-γup-regulated PD-L1 and IDO1 at the transcriptional level through the JAK-STAT-IRF1 axis,which was targeted and inhibited by MY.CONCLUSION Our research revealed a new insight into the anti-tumor effects of MY which inhibited IFN-γ-induced PD-L1 and IDO1 expression,supporting the potential of MY in anti-tumor immunotherapy.

Forkhead box P3 and indoleamine 2,3-dioxygenase co-expression in Pakistani triple negative breast cancer patients

BACKGROUND Forkhead box P3(FOXP3)is a specific marker for immunosuppressive regulatory T(T-reg)cells.T-regs and an immunosuppressive enzyme,indoleamine 2,3-dioxygenase(IDO),are associated with advanced disease in cancer.AIM To evaluate the co-expression of FOXP3 and IDO in triple negative breast cancer(TNBC)with respect to hormone-positive breast cancer patients from Pakistan.METHODS Immunohistochemistry was performed to analyze the expression of FOXP3,IDO,estrogen receptor,progesterone receptor,and human epidermal growth factor receptor on tissues of breast cancer patients(n=100):Hormone-positive breast cancer(n=51)and TNBC(n=49).A total of 100 patients were characterized as FOXP3 negative vs positive and further categorized based on low,medium,and high IDO expression score.Univariate and multivariate logistic regression models were used.RESULTS Out of 100 breast tumors,25%expressed FOXP3 positive T-regs.A significant coexpression of FOXP3 and IDO was observed among patients with TNBC(P=0.01)compared to those with hormone-positive breast cancer.Two variables were identified as significant independent risk factors for FOXP3 positive:IDO expression high(adjusted odds ratio(AOR)5.90;95%confidence interval(CI):1.22-28.64;P=0.03)and TNBC(AOR 2.80;95%CI:0.96-7.95;P=0.05).CONCLUSION Our data showed that FOXP3 positive cells might be associated with high expression of IDO in TNBC patients.FOXP3 and IDO co-expression may also suggest its involvement in disease,and evaluation of FOXP3 and IDO expression in TNBC patients may offer a new therapeutic option.

Indoleamine 2,3-dioxygenase in tumor induced tolerance

Objective To review the recent studies about the role of indoleamine 2,3-dioxygenase （IDO） in tumor induced tolerance. Data sources Published articles （1978-2009） on IDO and tumor induced tolerance were selected from Medline. Study selection Articles selected were relevant to development of IDO in tumor induced tolerance. Of all originally identified articles, 50 specially addressed the stated purpose. Results Recent work has revealed IDO at high levels in tumors and in tumor-draining lymph nodes and a close relationship between IDO activity and the regulatory T cells. Conclusion Up-regulation of IDO is proven to be a mechanism of acquired tolerance in tumors, in which the closely coupled positive feedback system between IDO and reclulatorv T cells may be considered to play an important role.

Indoleamine 2,3-dioxygenase and regulatory dendritic cells contribute to the allograft protection induced by infusion of donor-specific splenic stromal cells

It has been reported that splenic stromal cells(SSCs)are capable of directly supporting the development of CD11c ^(lo)CD45RB^(+) IL-10-producing dendritic cells(DCs)from lineage-negative c-kit^(+) progenitor cells in the absence of exogenous cytokines.In vitro,DCs that differentiate on stromal cells suppress mixed leukocyte reaction responses and induce primary alloreactive CD4^(+) T cells to differentiate into IL-10-producing Tr1 cells.However,the precise mechanisms by which these SSCs exert their regulatory functions in vivo remain undefined.Furthermore,their possible contribution to the development of allograft transplantation tolerance has yet to be examined.Here,we have used both murine skin and cardiac allograft transplantation models to explore whether in vivo alloresponses can be regulated by infusion with donor-derived SSCs and to investigate the possible mechanisms by which SSCs exert regulatory effects to prevent allograft rejection.We show that intravenous SSC infusion prolonged murine skin allograft survival.The prolonged graft survival is associated with augmentation of the generation of regulatory DC subsets and CD4^(+) CD25^(+) Foxp3^(+) regulatory T cells(Tregs),as well as upregulation of the production of suppressive cytokines IL-10 and transforming growth factor(TGF)-b.Moreover,we found that indoleamine 2,3-dioxygenase and SSC-derived regulatory DCs contribute to allograft protection by infusion of donor-specific SSCs.Our data suggest that donor-derived SSCs could be used as a therapeutic target to promote transplantation tolerance.

Indoleamine 2,3-Dioxygenase in Endometriosis

Endometriosis(EMS)is a chronic inflammatory and estrogen-dependent gynecological disease characterized by the presence of endometrial tissue outside the uterine cavity.Although it is a benign disease,EMS is tumor-like in several aspects,which include unrestrained growth,decreased apoptosis,and aggressive invasion.EMS involves endocrine disorders and immunological factors.Indoleamine 2,3-dioxygenase(IDO)is an intracellular enzyme that catalyzes the initial and rate-limiting step of the metabolism of tryptophan.IDO is a potential candidate facilitating EMS development.Increased IDO expression in both eutopic and ectopic endometria of women with EMS is biologically important in aspects,which include regulation of endometrial stromal cell function and modulation of adjacent local immunocytes to generate a supportive microenvironment.In turn,the expression of IDO can be regulated by the complex endocrine-immune microenvironment networks in endometrial lesions.Here,we systematically review the roles of IDO in EMS to explore its pathological implications and treatment potential.

Indoleamine-2,3-dioxygenase 1/cyclooxygenase 2 expression prediction for adverse prognosis in colorectal cancer

AIM To evaluate indoleamine-2,3-dioxygenase 1/cyclooxygenase 2(IDO1/COX2) expression as an independent prognostic biomarker for colorectal cancer(CRC) patients.METHODS We retrospectively studied the medical records of 95 patients who received surgical resection from August 2008 to January 2010. All patients were randomly assigned to adjuvant treatment with or without celecoxib groups after surgery. We performed standard immunohistochemistry to assess the expression levels of IDO1/COX2 and evaluated the correlation of IDO1/COX2 with clinicopathological factors and overall survival(OS) outcomes.RESULTS The expression of nuclear IDO1 was significantly correlated with body mass index(P < 0.001), and IDO1 expression displayed no association with sex, age, tumor differentiation, T stage, N stage, carcinoembryonic antigen, cancer antigen 19-9, CD3+ and CD8+ tumor infiltrating lymphocytes, and COX2. In univariate analysis, we found that nuclear IDO1(P = 0.039), nuclear/cytoplasmic IDO1 [hazard ratio(HR) = 2.044, 95% confidence interval(CI): 0.871-4.798, P = 0.039], nuclear IDO1/COX2(HR = 3.048, 95%CI: 0.868-10.7, P = 0.0049) and cytoplasmic IDO1/COX2(HR = 2.109, 95%CI: 0.976-4.558, P = 0.022) all yielded significantly poor OS outcomes. Nuclear IDO1(P = 0.041), nuclear/cytoplasmic IDO1(HR = 3.023, 95%CI: 0.585-15.61, P = 0.041) and cytoplasmic IDO1/COX2(HR = 2.740, 95%CI: 0.764-9.831, P = 0.038) have significantly poor OS outcomes for the CRC celecoxib subgroup. In our multivariate Cox model, high coexpression of cytoplasmic IDO1/COX2 was found to be an independent predictor of poor outcome in CRC(HR = 2.218, 95%CI: 1.011-4.48, P = 0.047) and celecoxib subgroup patients(HR = 3.210, 95%CI: 1.074-9.590, P = 0.037).CONCLUSION Our results showed that cytoplasmic IDO1/COX2 coexpression could be used as an independent poor predictor for OS in CRC.

吲哚胺2,3-双加氧酶1在胃癌中的研究进展

胃癌(Gastric Cancer,GC)是全球第五大最常见的恶性肿瘤,也是第四大癌症死亡相关原因。胃癌异质性明显,肿瘤微环境复杂,免疫检查点抑制剂虽然在晚期胃癌中展现出一定抗肿瘤疗效,但获益人群仍在少数。吲哚胺2,3-双加氧酶1(Indoleamine 2,3-Dioxygenase 1,IDO1)是色氨酸沿犬尿氨酸途径代谢中的关键酶,对肿瘤免疫逃逸起到了关键作用。目前已有多项研究表明IDO1在胃癌发生发展及幽门螺杆菌感染和EB病毒感染中发挥重要作用,所以靶向IDO1有望成为胃癌免疫治疗的新策略。本文就IDO1作用机制、IDO1在胃癌及相关疾病中的研究进展及IDO1抑制剂在胃癌中的应用前景进行综述。

基于虚拟筛选的新型吲哚胺2,3-双加氧酶抑制剂的发现及活性评价

目的应用药效团模型及分子对接的综合虚拟筛选策略,对Specs及Chembridge数据库进行筛选并进行生物学活性评价,以期发现新型吲哚胺2,3-双加氧酶(IDO1)抑制剂。方法基于已报道IDO1抑制剂,利用Discovery Studio 2019软件的Pharmacophores(Hiphop)模块构建药效团模型。通过最优药效团模型初步筛选了Specs及Chembridge数据库,后采用LibDock及CDOCKER程序靶向IDO1活性位点进行层级分子对接,最终保留了40个苗头化合物,并在100μmol/L浓度下进行了细胞水平IDO1酶抑制活性初筛。选取初筛抑制率大于50%的11个化合物进行细胞水平及生化水平抑酶活性的进一步测定。采用SPR及分子对接模型进一步确证及阐明化合物与IDO1酶之间的相互作用方式。结果发现羟基嘧啶类化合物29在细胞水平及生化水平上均呈现了IDO1酶抑制活性,EC50和IC50分别为(53.93±1.22)μmol/L和(179±8.12)μmol/L。SPR研究进一步确证了化合物29与IDO1之间的直接结合(KD=65.92μmol/L)。分子对接模型研究显示羟基嘧啶基团与IDO1的卟啉环之间存在较为丰富的相互作用,是靶向识别的关键基团。结论羟基嘧啶类化合物29是一类新型IDO1抑制剂,可作为IDO1酶抑制剂的先导物,通过进一步结构改造及优化,有望获得高效、结构新颖的IDO1抑制剂及新型肿瘤免疫治疗药物。

吲哚胺2,3-双加氧酶1对急性放射性肠道损伤的保护作用

目的:探讨吲哚胺2,3-双加氧酶1(IDO1)对急性放射性肠道损伤的作用。方法:使用TCGA和GTEX数据集中结肠癌、直肠癌组织和正常对照组织的测序结果,分析IDO1基因在肠癌组织及正常肠道组织中的表达情况。使用CRISPR/Cas9技术敲除鼠正常肠上皮IEC-6细胞中IDO1基因的部分第2、3外显子序列,建立鼠IEC-6的IDO1 KO(IDO1^(-/-))细胞系,并给予两个细胞系(野生型和IDO1^(-/-))放射处理。C57BL/6野生型小鼠和IDO1基因敲除(IDO1^(-/-))小鼠也给予腹部X射线照射以建立细胞和动物急性放射性肠道损伤模型。使用蛋白质印记法(Western blot)检测野生型和IDO1^(-/-)的IEC-6细胞及小鼠肠道组织中上皮紧密连接蛋白在放射前、后的蛋白表达水平。结果:Western blot证实IDO1在鼠IEC-6细胞、肠道组织中均有表达。对TCGA和GTEX数据集分析后也同样看到IDO1基因在结肠癌、直肠癌、正常肠道组织中均有表达,但癌组织中IDO1水平较正常肠道组织高(P<0.05)。体内外的放射照射后,IDO1、Claudin 1、Occludin、ZO-1等出现明显变化:与放射前比,放射后的细胞和小鼠组织中的IDO1的表达水平升高(P<0.05),而紧密连接蛋白Claudin 1、Occludin、ZO-1则下降(P<0.05);与野生型IEC-6细胞和小鼠相比,在IDO1^(-/-)IEC-6细胞和小鼠肠组织中,Claudin 1、Occludin、ZO-1下降更显著(P<0.05)。结论:IDO1在急性放射性肠道损伤中起保护作用,其保护作用可能是通过保护肠上皮细胞间紧密连接功能而实现的。

复发性流产患者子宫内膜IDO、CD56、CD163表达变化及其临床预测价值

目的:分析复发性流产患者子宫内膜吲哚胺2,3-双加氧酶(IDO)、CD56、CD163表达变化及其临床预测价值。方法:选取82例复发性流产患者为研究对象(研究组);95例人工流产终止妊娠的健康孕妇为对照组。比较两组患者子宫内膜IDO、CD56、CD163表达情况、临床资料;多因素Logistic回归分析引起复发性流产的危险因素;绘制受试者工作特征曲线(ROC)分析子宫内膜IDO、CD56单独及联合检测对复发性流产的预测价值。结果:研究组IDO阴性率、CD56^(+)细胞百分率均高于对照组(P<0.05)。多因素Logistic回归分析显示,吸烟、被动吸烟、作息不规律、IDO阴性、CD56^(+)细胞百分率升高均为复发性流产的危险因素(P<0.05)。ROC曲线分析显示,IDO、CD56单独及联合检测对复发性流产的曲线下面积(AUC)为0.810、0.698、0.878,联合检测最高。结论:复发性流产患者子宫内膜IDO阳性表达更低,CD56表达水平更高,但CD163表达水平变化不明显,吸烟或被动吸烟、作息不规律、IDO阴性、CD56^(+)细胞百分率升高均是复发性流产的危险因素,IDO、CD56联合检测复发性流产预测价值更高。

不同棘球蚴抗原诱导树突状细胞表达吲哚胺2,3-双加氧酶的实验研究

目的检测不同的棘球蚴抗原体外诱导树突状细胞(DCs)表达吲哚胺2,3-双加氧酶(IDO)的情况。方法从C57BL/6小鼠股骨中分离出骨髓细胞,用小鼠重组巨噬细胞集落刺激因子(rmGM-CSF)诱导后,获得小鼠骨髓源树突状细胞(BMDCs)。分别用重组抗原B(rAgB,15μg/ml)、小鼠细粒棘球蚴囊液(MHF,5 mg/ml)、γ干扰素(IFN-γ,1 000 U/ml,为阳性对照)和RPMI 1640完全培养液(阴性对照)刺激DCs,于18、24和48 h后收集细胞和细胞上清。采用流式细胞术检测各组DCs的表面标志物CD40、CD80、CD86和I-A/I-E的阳性表达情况,并利用实时荧光定量PCR(FQ-RT-PCR)检测各组的IDO mRNA相对转录水平。利用高效液相色谱法(HPLC)检测各组细胞上清中的色氨酸(Try)浓度。结果流式细胞术检测结果显示,DCs受rAgB和MHF刺激后,其表面标志物CD40、CD80、CD86和I-A/I-E的阳性表达率均降低。刺激24 h后,rAgB组的CD40、CD86和I-A/I-E阳性表达率分别为(22.60±2.69)%、(35.50±4.38)%和(57.30±4.38)%,与MHF组[(38.00±3.54)%、(53.00±3.39)%和(77.10±1.70)%]和阴性对照[(37.95±3.61)%、(19.55±1.06)%和(85.45±1.63)%]的差异均有统计学意义(P<0.05)。FQ-RT-PCR结果显示,刺激18、24和48 h后,rAgB组的IDO mRNA水平[(9.20±0.01)、(29.44±0.02)和(16.48±0.04)]和MHF组的[(9.67±0.02)、(17.52±0.01)和(16.81±0.01)]均高于阴性对照组[(2.46±0.01)、(7.77±0.01)和(10.56±0.01)](P<0.01),rAgB组和MHF组IDO mRNA水平的差异均有统计学意义(P<0.05)。HPLC结果显示,刺激18、24和48 h后,rAgB组DCs上清中的色氨酸浓度[(23.65±0.64)、(13.95±1.06)和(19.05±0.64)μmol/L]均较其他3组低,刺激24 h后的色氨酸浓度与阴性对照组(22.90±0.14)和MHF组(20.65±0.35)的差异均有统计学意义(P<0.05)。结论在体外实验条件下,rAgB、MHF均可上调DCs表面IDO的表达,作用24 h后,rAgB上调IDO的能力强于MHF。

急性髓细胞白血病细胞的吲哚胺2,3-双加氧酶介导免疫逃逸的实验研究

为了探讨急性髓细胞白血病细胞的吲哚胺2,3-双加氧酶(IDO)参与肿瘤免疫逃逸的机制,从23例急性髓性白血病患者获取骨髓细胞,采用免疫组织化学染色法和RT-PCR法检测白血病细胞IDO的表达;在有或无1-甲基色氨酸(1-MT)存在下,以白血病细胞为刺激细胞,外周T淋巴细胞为反应细胞建立单向混合淋巴细胞反应体系(MLR),利用MTT法检测T淋巴细胞增殖率,并以反相高效液相色谱法检测相应MLR体系上清液中的IDO活性。结果显示,在23例急性髓细胞白血病患者中17例患者的骨髓白血病细胞上有IDO的表达;白血病细胞上的IDO活性抑制MLR体系中T淋巴细胞的增殖。结论:白血病细胞表达的IDO活性能阻抑外周T淋巴细胞的增殖,它可能参与了肿瘤免疫逃逸。

吲哚胺2,3双加氧酶促进血管形成的体外实验研究

目的:观察吲哚胺2,3双加氧酶(Indoleamine2,3-dioxygenase,IDO)对人脐静脉内皮细胞(Human umbilical veinendothelial cells,HUVEC)增殖、CD105表达及成管能力的影响。方法:利用Transwell小室建立高表达IDO的MCF-7与HUVEC共培养模型,通过IDO抑制剂1-甲基色氨酸(1-MT)阻滞IDO活性,观察共培养后HUVEC的增殖情况,流式细胞仪检测其表面CD105的表达率,基质胶成管实验观察管样结构的形成。结果:MCF-7的IDO表达水平较高且具有功能活性。与MCF-7共培养后,HUVEC增殖明显,CD105的表达增加,管样结构形成的数量增加,经IDO抑制剂1-MT处理后HUVEC增殖受到抑制,CD105表达降低,管样结构数量明显减少。结论:IDO可以促进HUVEC的增殖、活化并提高其形成管样结构的能力,为进一步研究IDO促进肿瘤进展的机制提供了实验基础。