Lidamycin Induces Apoptosis of B-Cell Lymphoma Cells and Inhibits Xenograft Growth in Nude Mice

OBJECTIVE To study the cytotoxicity of Lidamycin (LDM) and its induction of apoptosis in Raji and Daudi cells of B-cell lymphoma, and the inhibition of growth of the lymphoma Raji xenograft in nude mice.METHODS MTT assay was used to observe the inhibition by LDM on the proliferation of the Raji and Daudi cells. Annexin V-FITC/PI double-stain, in combination with flow cytometry (FCM), was used to determine the induction of apoptosis by LDM in Raji cells. The B-cell lymphoma Raji xenograft model in nude mice was set up to detect the in vivo antitumor activity of LDM.RESULTS LDM markedly inhibited the proliferation of the Raji and Daudi cells in vitro, with IC50 values of 7.13×10-11 mol/L and 2.91×10-10 mol/L, respectively. The apoptotic rates of Raji cells were respectively 77.98% and 67.63% at 0.5 nmol/L and 0.25 nmol/L of LDM, indicating an obvious induction of apoptosis in Raji cells. LDM inhibited the formation and growth of human B-cell lymphoma Raji xenograft in nude mice. The inhibition rates of tumor growth were respectively 74.9% and 65.2% in LDM at dosage group of 0.05 mg/kg and 0.025 mg/kg, suggesting an apparent prolongation of survival time in the nude mouse bearing lymphoma.CONCLUSION LDM can effectively induce apoptosis of the B-cell lymphoma cells and inhibit the xenograft growth in nude mice.     

MDA-7/IL-24对Burkitt淋巴瘤细胞的诱导分化作用

目的:研究黑色素瘤分化相关基因-7(melanoma differentiation associated gene 7,MDA-7)/IL-2对Burkitt淋巴瘤细胞的促分化作用并探讨其作用机制.方法:构建稳定过表达MDA-7/IL-24的人Burkitt淋巴瘤Raji和Daudi细胞株,MTS法检测稳定转染MDA-7/IL-24对Raji和Daudi细胞活力的影响;Transwell小室实验检测转染MDA-7/IL-24对Raji和Daudi细胞侵袭和迁移能力的影响;流式细胞术检测细胞凋亡水平及免疫表型;Western blotting技术检测转染MDA-7/IL-24对Raji和Daudi细胞表达分化相关蛋白Myb、BLIMP1及BCL-6的影响;建立裸鼠Raji细胞移植瘤模型,检测在体内环境中稳定转染MDA-7/IL-24对Raji细胞生物活性的影响.结果:过表达MDA-7/IL-24的Raji和Daudi细胞其增殖(P.＜0.05)、侵袭(P＜0.01)及迁移(P＜0.01)能力均明显下降,但凋亡细胞无明显增加(P＞0.05),表达CD45及CD138的水平均明显增加(P＜0.01),而表达CD10的水平明显下降(P＜0.01).过表达MDA-7/IL-24的Raji和Daudi细胞表达BLIMP1的水平明显增加(P＜0.01),而表达Myb及BCL-6的水平均明显减低(P＜0.01).MDA-7/IL-24过表达组裸鼠模型Raji细胞移植瘤质量明显低于对照组[(1.23±0.21)vs(1.96±0.24)g,P＜0.01].结论:转染MDA-7/IL-24可能通过诱导分化作用抑制Burkitt淋巴瘤细胞的生物活性.     

Anti-tumor effect and its mechanisms of ursolic acid on human esophageal carcinoma cell Eca-109 <Emphasis Type="Italic">in vivo</Emphasis>

Objective： To investigate the anti-tumor effect and possible mechanisms of ursolic acid on human esophageal carcinoma in vivo. Methods： Atransplanted tumor model by injecting Eca-109 cells into subcutaneous tissue of BALB/c nude mice was established. 40 nude mice bearing tumors were randomly divided into 4 groups and 0.2 ml saline or 0.2 ml ursolic acid （25-100 mg·kg^-1·d^-1） was injected into abdominal cavity respectively once everyday and lasted for fourteen days. The changes of tumor volume were measured continuously and tumor inhibition rate was calculated. The morphological changes of apoptosis were observed by electron microscope. The expressions of COX-2, bcl-2 and Bax protein in transplanted tumors were detected by immunohistochemistry. At last the PGE2 level of transplanted tumors was detected byradioimmunoassay. Results： Treatment of nude mice with 25, 50, or 100 mg·kg^-1·d^-1 of ursolic acid significantly inhibited the growth of the human esophageal carcinoma tumor in nude mice and induced Eca-109 cells apoptosis as demonstrated by electron microscopy analyses. The expressions of COX-2 and bcl-2 in the transplanted tumors were decreased in ursolic acid groups, while the Bax increased. The PGE2 level of transplanted tumors was decreased in ursolic acid groups with adose-relatedmanner. Conclusion： Ursolic acid has anti-tumor effects against human esophageal carcinoma cells in vivo, which are likely mediated via induction of tumor cell apoptosis and inhibition of COX-2 and PGE2.     

Inhibition of human B-cell lymphoma by an anti-CD20 antibody and its chimeric F(ab')2 fragment via induction of apoptosis

Monoclonal antibodies (mAb) directed against CD20, either unmodified or in radiolabeled forms, have been successfully used in clinic as effective therapeutic agents in the management of non-Hodgkin's B-cell lymphoma. Despite all clinical success the exact mechanisms of action of various anti-CD20 antibodies remains mostly unclear. Several mechanisms have been proposed to be responsible for the therapeutic activity of anti-CD20 antibodies, including antibody-dependent cell-mediated cytotoxicity, complement-mediated cytotoxicity, and direct inhibition of tumor growth via induction of apoptosis. We previously produced an anti-CD20 mAb, HI47, and showed that the antibody effectively blocked human B-cell proliferation in vitro and inhibited xenografted B-cell lymphoma in nude mice. In this study, we engineered the chimeric versions of both the Fab and F(ab)'2 fragments of HI47 and produced the fragments in E. coli. Both fragments competed efficiently with HI47 for binding to CD20+ B cells, and inhibited proliferation of B-lymphoma cells in a dose-dependent manner. Mechanistic studies revealed that both antibody fragments induced significant degree of B-cell apoptosis that is independent of any cross-linking agents. Further, both the F(ab)'2 and Fab fragments when administered in vivo significantly inhibited the growth of human B-cell lymphoma xenografts in nude mice. The bivalent F(ab)'2 fragment showed consistently better efficacy compared to its monovalent Fab counterpart in inducing apoptosis and inhibiting B-cell lymphoma growth both in vitro and in vivo. Taken together, these observations suggest that HI47 and its fragments most likely exert their antitumor activity through induction of cell apoptosis, and cross-linking/dimerization of CD20 molecules on B- cell surface is an important, but not essential, process for therapeutic efficacy of HI47 and its fragments.     

Biodistribution and anti-tumor activities of the 131I-labeled rituximab in nude mice bearing human Burkitt’s lymphoma

OBJECTIVE To explore the biodistribution and anti-tumor activity of 131 I labeled rituximab injected intratumorally or intraperitoneally in vivo in nude mice bearing Raji human Burkitt＇ s lymphoma xenografts. METHODS The rituximab and the mouse IgG were labeled with Na131 I using the IODO-GEN method. BALB/C nude mice were xenografted with 131 I-Rituximab or 131I-IgG and killed on the 1st, 3rd, 7th, and 15th day after injection. The tumor/non-tumor ratio （T/ NT） and the dose injected in each gram of the tissue （%ID/g） from 12 organs or tissues of interest, e.g. tumor, blood, were calculated. The long and short axes of each tumor were measured by calipers at 2-3-day intervals after treatment, and the growth inhibition of the tumor was calculated using the MIRD formula. RESULTS When comparing intraperitoneal injection （IP） and intratumoral injection （IT） of 131 I-IgG, intratumoral injection of 131 I-rituximab produced a significantly higher tumor/non-tumor ratio in all tissues and organs of interest on the 1st, 3rd, and 7th day, respectively （P 〈 0.05）. The %ID/g of tumor was 1.4-1.7-fold and 1.5-3.7-fold in the IP and IgG IT groups, respectively, but the %ID/g of non-tumors was significantly lower in the IP group and IgG IT group. Similarly, the tumor growth was greatly inhibited by intratumoral injection of the 131 I-rituximab, whereas it was less inhibited by other forms of the treatment （P 〈 0.05）. However 131 I-rituximab injected intratumorally inhibited tumor growth in a dose-dependent manner. The inhibition rate was less with a low dose （75 μCi） and greater with a high dose （150 μCi）, yet the difference was not significant （P 〉 0.05）. CONCLUSION Tumors can absorb the highest amount of the radiolabelled antibodies, and the tumor/non-tumor ratios in the group with intratumoral injection of the 131 I-rituximab resulted in the optimal anti-tumor activity.     

BET抑制剂对弥漫性大B细胞淋巴瘤细胞生长及外周血Th17细胞数量和相关细胞因子表达的影响

目的:探讨溴结构域和超末端结构域（bromodomain and extra terminal domain，BET）抑制剂对弥漫性大B细胞淋巴瘤CRL-2630细胞生长的影响，以及对弥漫性大B细胞淋巴瘤BALB/c-nu裸鼠外周血中辅助性T细胞17（helper T cells,Th17）数量和相关细胞因子表达的影响。方法:培养弥漫性大B细胞淋巴瘤株CRL-2630，使用不同浓度BET抑制剂（2、4、8、16、32 nmol/L）处理48 h，32 nmol/L BET抑制剂处理不同时间（12、24、36、48 h），CCK-8法检测各处理细胞活性；集落形成实验检测不同BET抑制剂浓度处理后细胞集落形成能力；Annexin V-FITC/PI双染法检测不同BET抑制剂浓度处理后细胞凋亡情况；实时荧光定量PCR与Western blot检测32 nmol/L BET抑制剂处理CRL-2630细胞48 h后HMGA1 mRNA与蛋白的表达水平；构建HMGA1过表达载体并通过脂质体介导法转染CRL-2630细胞，并用32 nmol/L BET抑制剂处理48 h，检测细胞活性与凋亡情况；构建裸鼠弥漫性大B细胞淋巴瘤模型并采集外周血，流式细胞术检测Th17细胞比例，ELISA法检测相关细胞因子的含量。结果:在一定范围内，BET抑制剂呈剂量依赖性地抑制CRL-2630细胞的活性，32 nmol/L BET抑制剂以时间依赖性地抑制CRL-2630细胞的活性。随着BET抑制剂处理浓度的增高，CRL-2630细胞集落形成能力逐渐下降，凋亡率逐渐升高。32 nmol/L BET抑制剂处理CRL-2630细胞48 h后，细胞中HMGA1的mRNA和蛋白水平均明显下降。pcDNA3.4-HMGA1转染CRL-2630细胞再使用BET抑制剂处理后，细胞的活性升高而凋亡率明显下降。弥漫性大B细胞淋巴瘤裸鼠经BET抑制剂作用后，外周血Th17细胞比例和IL-6、IL-17、IL-23含量较生理盐水组明显下降。结论:BET抑制剂能有效抑制 CRL-2630细胞活性，并诱导其凋亡，在一定范围内呈时效和量效关系。BET抑制剂还可以抑制弥漫性大B细胞淋巴瘤裸鼠外周血Th17细胞数量和相关细胞炎性因子的分泌，其作用机制可能与HMGA1的表达下调有关。     

Oligonucleotides complementary to c-myb messenger RNA inhibit growth and induce apoptosis in human Burkitt lymphoma cells

A 24-mer (antisense) phosphorothioate oligonucleotide (ODN) corresponding to the codons 2-9 of the c-myb gene was evaluated for its effects on the growth of a human Burkitt lymphoma cell line (Raji) in vitro. Raji cells incubated with different concentrations of c-myb antisense ODN (5-15 mu g/ml) for 24-72 h showed a significant dose-dependent decrease in growth. The same concentrations of control (sense) or scrambled c-myb phosphorothioate ODNs did not inhibit Raji cell growth. The c-myb antisense ODN, but not the control ODNs, significantly decreased c-myb mRNA levels in treated cells as determined by RT-PCR. Additionally, the c-myb antisense ODN induced apoptosis of Raji cells as demonstrated by i) flow cytometry to enumerate the A(o) (apoptotic cell population) population of propidium iodide stained cells; ii) electron microscopy to evaluate the cell morphology; and iii) DNA fragmentation pattern. Thus, an antisense c-myb ODN causes significant growth inhibition of Burkitt lymphoma cells, and one mechanism of growth inhibition is the induction of apoptosis of the lymphoma cells. In addition, antisense c-myb ODN did not reduce CFU-GM or BFU-e colony-forming ability of normal hematopoietic stem/progenitor cells. Because the inhibition is sequence-specific and Burkitt lymphoma cell selective, evaluation of the therapeutic effects of c-myb antisense ODN against Burkitt lymphoma is warranted.     

The RON receptor tyrosine kinase is a potential therapeutic target in Burkitt lymphoma

Background: Aberrant expression of the RON receptor tyrosine kinase is associated with tumor progression and carcinogenesis. The aims of this study were to determine the role and functional mechanisms of RON in Burkitt lymphoma (BL) and to document its potential as a therapeutic target. Methods: RON expression was determined in BL cell lines by western blot analysis and examined in human lymphoma specimens by both western blotting and immunohistochemistry. The correlation between RON expression and Epstein-Barr virus (EBV) infection was investigated. Raji cells were treated with the Zt/f2 anti-RON mAb and cell viability, colony formation, apoptosis and cell cycle arrest were measured in vitro using cell proliferation assays, colony-forming assays and flow cytometry. Downregulation of RON by Zt/f2 was validated in mice bearing Raji cell xenografts.Results: Immunohistostaining showed a high frequency of RON⁺ cells in BL tissues and RON expression strongly correlated with EBV positivity. RON downregulation significantly decreased cell proliferation and colony formation via promotion of apoptosis and cell cycle arrest in Raji cells. The in vivo study showed that RON knockdown inhibits the tumorigenic potential of Raji cells in nude mice.Conclusions: RON acts as an oncogene in the carcinogenesis and progression of BL and is therefore a potential target for therapeutic intervention.     

二烯丙基二硫对人胃癌细胞裸鼠移植瘤的抗肿瘤作用

背景与目的:既往研究发现二烯丙基二硫(diallyldisulfide,DADS)在体外可抑制多种肿瘤细胞生长,但在体内抗肿瘤作用的研究报道较少。本实验旨在探讨DADS对人胃癌细胞移植瘤在BALB/C裸鼠体内生长的影响。方法:未经药物处理和经30mg/LDADS处理1天的胃癌细胞MGC803接种于裸鼠皮下;观察体外DADS处理MGC803细胞裸鼠移植瘤的成瘤情况和未处理MGC803细胞移植瘤成瘤后腹腔注射DADS对胃癌移植瘤在BALB/c裸鼠体内生长情况的影响。Westernblot检测瘤组织中增殖细胞核抗原(proliferatingcellnuclearantigen,PCNA)的表达情况。结果:30mg/LDADS处理的MGC803细胞移植裸鼠体内无一成瘤。荷瘤裸鼠腹腔注射DADS剂量为50、100和200mg/kg时的抑瘤率分别为27.8%、66.1%和73.0%,同时可抑制移植瘤癌细胞PCNA的表达。结论:DADS可明显降低胃癌细胞裸鼠移植瘤的成瘤性,并对移植瘤生长有明显抑制作用。     

Effects of interferon-α on human b cells: Repression of apoptosis and prevention of cell growth are independent responses of burkitt lymphoma lines

We have previously shown that interferon-α (IFN-α) can repress apoptosis in Burkitt lymphoma (BL) cells. In this study, we have compared this protective response with a further, well-established effect of IFN-α on BL cells, that of growth arrest. Of a panel of BL lines comprising (i) EBV-positive and -negative lines that retain the phenotype of the parental tumour cells and (ii) the prototype IFN-α-growth-inhibited line, Daudi, only Daudi cells were found to undergo substantial growth inhibition in response to the cytokine. By contrast, all lines, with the notable exception of Daudi, were protected by IFN-α from high-rate apoptosis initiated by the Ca²⁺ ionophore ionomycin. lonomycin failed to elicit an IFN-α-repressible apoptotic response in either wild-type Daudi cells or IFN-resistant sublines that were refractory to the growth-arresting effects of the cytokine. Analysis of c-myc protein levels confirmed previous observations that repression of apoptosis in IFN-α-rescuable BL cells was associated with an early inhibition of myc that was followed by a return to high-level expression. Significantly, ionomycin alone induced a comparable transient inhibition of myc protein in Daudi cells. In Daudi cells, but not in IFN-α-rescuable BL cells, renewed expression of myc observed after the early, transient down-regulation was followed by sustained down-regulation of the protein, which paralleled growth arrest. Our results indicate that long-term growth arrest and repression of apoptosis in BL are distinct cellular responses to IFN-α. © 1995 Wiley-Liss, Inc.     

Suppression of Angiogenesis and Therapy of Human Colon Cancer Liver Metastasis by Systemic Administration of Interferon-α

The purpose of this study was to determine whether systemic administration of interferon-alpha (IFN-α) can inhibit liver metastasis produced in nude mice by human colon cancer cells. KM12L4 (IFN-α-sensitive) or KM12L4 IFN^R (IFN-α-resistant) cells were injected into the spleen of nude mice. Seven days later, the mice were treated with subcutaneous (s.c.) injections of IFN-α (70,000 units/week) at different dosing schedules (1, 2, or 7 times/week). Significant inhibition of tumor growth, vascularization and expression of basic fibroblast growth factor (bFGF) or matrix metalloproteinase-9 (MMP-9) mRNA and protein occurred in mice given daily injections of IFN-α. Kinetic analysis of therapy showed that daily s.c. administrations of 10,000 units of IFN-α induced apoptosis in liver metastasis-associated endothelial cells, followed by inhibition of tumor cell division and apoptosis of tumor cells. These data suggest that the antiangiogenic activity of IFN-α-2a depends on frequent administration of the optimal biologic dose.     

AEE788, a dual tyrosine kinase receptor inhibitor, induces endothelial cell apoptosis in human cutaneous squamous cell carcinoma xenografts in nude mice.

PURPOSE: We investigated whether concomitant blockade of the epidermal growth factor receptor (EGFR) and vascular endothelial growth factor receptor (VEGFR) signaling pathways by AEE788, a dual inhibitor of EGFR and VEGFR tyrosine kinases, would inhibit the growth of cutaneous squamous cell carcinoma (SCC) cells and human cutaneous cancer xenografts in nude mice. EXPERIMENTAL DESIGN: We examined the effects of AEE788 on the phosphorylation of EGFR and VEGFR-2 in cutaneous SCC cells expressing EGFR and VEGFR-2 and cutaneous SCC cell growth and apoptosis. We assessed the in vivo antitumor effects of AEE788 in a xenograft model in nude mice. AEE788 (50 mg/kg) was given orally thrice weekly to mice that had been s.c. injected with Colo16 tumor cells. Mechanisms of in vivo AEE788 activity were determined by immunohistochemical analysis. RESULTS: Treatment of cutaneous SCC cells with AEE788 led to dose-dependent inhibition of EGFR and VEGFR-2 phosphorylation, growth inhibition, and induction of apoptosis. In mice treated with AEE788, tumor growth was inhibited by 54% at 21 days after the start of treatment compared with control mice (P < 0.01). Immunohistochemical analysis revealed that AEE788 inhibited phosphorylation of EGFR and VEGFR and induced apoptosis of tumor cells and tumor-associated endothelial cells. CONCLUSIONS: In addition to inhibiting cutaneous cancer cell growth by blocking EGFR and VEGFR signaling pathways in vitro, AEE788 inhibited in vivo tumor growth by inducing tumor and endothelial cell apoptosis.     

A bispecific recombinant immunotoxin, DT2219, targeting human CD19 and CD22 receptors in a mouse xenograft model of B-cell leukemia/lymphoma.

A novel bispecific single-chain fusion protein, DT2219, was assembled consisting of the catalytic and translocation domains of diphtheria toxin (DT(390)) fused to two repeating sFv subunits recognizing CD19 and CD22 and expressed in Escherichia coli. Problems with yield, purity, and aggregation in the refolding step were solved by incorporating a segment of human muscle aldolase and by using a sodium N-lauroyl-sarcosine detergent-based refolding procedure. Problems with reduced efficacy were addressed by combining the anti-CD19 and anti-CD22 on the same single-chain molecule. DT2219 had greater anticancer activity than monomeric or bivalent immunotoxins made with anti-CD19 and anti-CD22 sFv alone and it showed a higher level of binding to patient leukemia cells and to CD19(+)CD22(+) Daudi or Raji cells than did anti-CD19 and anti-CD22 parental monoclonal antibodies. The resulting DT2219, mutated to enhance its avidity, was cytotoxic to Daudi cells in vitro (IC(50) = 0.3 nmol/L). In vivo, DT2219 was effective in a flank tumor therapy model in which it significantly inhibited tumor growth (P < 0.05) and in a systemic model in which it significantly prolonged survival of severe combined immunodeficient mice with established Daudi (P < 0.008) compared with controls. DT2219 has broader reactivity in recognizing B-cell malignancies, has more killing power, and requires less toxin than using individual immunotoxin, which warrants further investigation as a new drug for treating B leukemia/lymphoma.     

Effects of adenoviral wild-type p53 gene transfer in p53-mutated lymphoma cells

The present study assessed the role of adenoviral vector-mediated wild-type p53 gene transfer in B lymphoma cells. Deficiency of p53-mediated cell death is common in human cancer contributing to both tumorigenesis and chemoresistance. Lymphoma cells are being considered as suitable targets for gene therapy protocols. Recently, we reported an adenoviral protocol leading to highly efficient gene transfer to B lymphoma cells. All lymphoma cell lines (n=5) tested here showed mutations in the p53 gene locus. The aim of this work was to transduce lymphoma cells with the wild-type p53 gene. Using this protocol, 88% of Raji, 75% of Daudi, and 45% of OCI-Ly8-LAM53 cells were transfected with the reporter gene green fluorescent protein at a multiplicity of infection of 200. The expression of green fluorescent protein in CA46 and BL41 cells was 27% and 42%, respectively. At this multiplicity of infection, growth characteristics of lymphoma cell lines were not changed significantly. In contrast, cells transduced with wild-type p53 gene showed an inhibition of proliferation as well as an increase in apoptosis. Cell loss by apoptosis after p53 gene transfer was up to 40% as compared to transduction with an irrelevant vector. In addition, we determined the effects of DNA damage produced by the DNA topoisomerase II inhibitor etoposide on wild-type p53 transfected lymphoma cells. In Ad-p53-transfected Raji cells, treatment with the drug resulted in a marked increase of cell loss in comparison to Ad-beta-Gal-transfected cells (45% vs. 77%). Interestingly, performing cytotoxicity studies, we could show an increased sensitivity of Raji and Daudi cells against immunological effector cells. In conclusion, transduction of wild-type p53 into lymphoma cells expressing mutated p53 was efficient and led to inhibition of proliferation and increase in apoptotic rate in some cell lines dependent on p53 mutation. This protocol should have an impact on the use of lymphoma cells in cancer gene therapy protocols.     

Novel oral histone deacetylase inhibitor,MPT0E028, displays potent growth-inhibitory activity against human B-cell lymphoma in vitro and in vivo

Histone deacetylase (HDAC) inhibitor has been a promising therapeutic option in cancer therapy due to its ability to induce growth arrest, differentiation, and apoptosis. In this study, we demonstrated that MPT0E028, a novel HDAC inhibitor, reduces the viability of B-cell lymphomas by inducing apoptosis and shows a more potent HDAC inhibitory effect compared to SAHA, the first HDAC inhibitor approved by the FDA. In addition to HDACs inhibition, MPT0E028 also possesses potent direct Akt targeting ability as measured by the kinome diversity screening assay. Also, MPT0E028 reduces Akt phosphorylation in B-cell lymphoma with an IC₅₀ value lower than SAHA. Transient transfection assay revealed that both targeting HDACs and Akt contribute to the apoptosis induced by MPT0E028, with both mechanisms functioning independently. Microarray analysis also shows that MPT0E028 may regulate many oncogenes expression (e.g., TP53, MYC, STAT family). Furthermore, in vivo animal model experiments demonstrated that MPT0E028 (50–200 mg/kg, po, qd) prolongs the survival rate of mice bearing human B-cell lymphoma Ramos cells and inhibits tumor growth in BJAB xenograft model. In summary, MPT0E028 possesses strong in vitro and in vivo activity against malignant cells, representing a potential therapeutic approach for cancer therapy.     

三氧化二砷的抗大肠癌作用及其机制

目的观察三氧化二砷(As2O3)对大肠癌LS-174T细胞生长及端粒酶活性的影响。方法As2O3作用于大肠癌LS-174T细胞和裸鼠移植瘤后,采用噻唑盐(MTT)比色法检测结肠癌细胞生长抑制情况,电镜检测细胞超微结构的改变,荧光染色观察细胞核形态变化,流式细胞术(FCM)检测As2O3对细胞周期的影响,聚合酶链反应-酶联免疫反应(PCR-ELISA)试剂盒检测细胞中端粒酶活性变化。结果MTT法显示,随着As2O3浓度的升高,LS-174T细胞存活率明显下降,IC50= 5.23μmol/L。As2O3作用于LS-174T细胞24 h即出现凋亡峰,凋亡细胞的数量随着作用时间增加而增加。As2O3对LS-174T细胞提取液端粒酶活性有一定的抑制作用,对癌细胞端粒酶活性抑制作用随作用时间的延长而加强。从实验动物瘤体积和瘤重两个指标分析,As2O3组与对照组相比具有明显的抑癌作用(P<0.05)。结论经体外、体内实验证实,As2O3对结肠癌LS-174T细胞生长和裸鼠移植瘤均有抑制作用,其抗癌机制可能与诱导细胞凋亡和抑制端粒酶活性有关。     

转染TRAIL的内皮祖细胞对人卵巢癌裸鼠皮下移植瘤的抑制作用

背景与目的:肿瘤坏死因子相关凋亡诱导配体(tumornecrosisfactor-relatedapoptosisinducingligand,TRAIL)有广谱的抗瘤作用,且对正常组织细胞无毒性,因此有望应用于肿瘤基因治疗。内皮祖细胞(endothelialprogenitorcells,EPCs)在体内能定向归巢于肿瘤,参与肿瘤新生血管的建立。本研究以EPC为载体,观察TRAIL转染EPCs对人卵巢上皮癌裸鼠皮下移植瘤的治疗作用。方法:用磁珠分离法从脐血中分离EPCs,并进行体外培养扩增。用脂质体将带有GFP-TRAIL基因的质粒转入EPCs(TRAIL-EPCs)。将转染后的EPC经尾静脉注入3AO卵巢癌裸鼠皮下移植瘤模型。流式细胞仪检测各组中绿色荧光蛋白(Green-Fluoroprotein,GFP)表达情况,观察各组移植瘤体积的变化,计算抑瘤率。结果:静脉注射转染TRAIL后的EPC,对卵巢上皮癌裸鼠皮下移植瘤生长具有明显抑制作用,对照组裸鼠的瘤重(0.226±0.209)g,而TRAIL细胞因子治疗组、GFP-TRAIL转染组裸小鼠的瘤重分别为(0.118±0.164)g、(0.075±0.084)g;TRAIL细胞因子组的抑瘤率为48.1%,TRAIL转染组抑瘤率为66.9%。肿瘤组织石蜡切片HE染色检查显示TRAIL细胞因子组,TRAIL转染组转对照组有更多的出血坏死区。TRAIL细胞因子组,TRAIL转染组均无明显毒副作用的表现。结论:TRAIL细胞因子和TRAIL-EPCs对人卵巢癌裸鼠皮下移植瘤均有明显的抑制作用,EPC在裸鼠皮下移植瘤模型体内有一定的导向作用,有希望成为基因治疗的载体。     

不同给药方式下三氧化二砷对T细胞淋巴瘤EL4细胞体内及体外抑制作用

背景与目的：体外实验证明,三氧化二砷（arsenictrioxide,As2O3）单药可抑制多种恶性淋巴瘤细胞的增殖,并呈时间依赖性和浓度依赖性。临床研究也提示,As2O3单药治疗多种病理亚型淋巴瘤有效。但目前As2O3的剂量、具体用法仍未确定。本实验研究不同给药方式As2O3对鼠源性T细胞淋巴瘤EIA细胞体内外的抗瘤作用,旨在了解As2O3不同给药方法对T细胞淋巴瘤疗效及不良反应。方法：MTT法检测8种浓度As2O3对EL4细胞的抑制作用,流式细胞仪分析、AnnexinV—FITC／PI双标记检测细胞凋亡,电镜观察凋亡形态变化。建立EIA细胞裸鼠移植瘤模型,观察不同方案腹腔注射As2O3对EIA裸鼠移植瘤的抑制作用及裸鼠的耐受情况。结果：与对照组相比,不同浓度As2O3对EL4细胞均存在直接抑制作用（P〈0．05）,作用72h时的IC50为1．28μmol／L。体内实验显示,4mg·（kg·d）^-1×7d与2mg·（kg·d）^-1×14d给药对裸鼠移植瘤的抑制作用相近,抑瘤率分别为58．8％和55．6％（P〈0．351）。移植瘤组织凋亡细胞增多并可见凋亡小体生成。毒性表现主要为急性肝损害的病理学变化。结论：As20,体外可抑制EIA细胞增殖并可以诱导细胞凋亡,在总剂量相同的情况下,4mg·（kg·d）^-1×7d与2mg·（kg·d）^-1×14d的给药方式对裸鼠移植瘤生长的抑制作用近似。