建立小鼠淋巴瘤模型所需环磷酰胺最佳预处理剂量探索

目的:探讨不同剂量环磷酰胺对小鼠肿瘤成模情况的影响,寻找一种简单、有效的建立肿瘤模型的预处理方法。方法:给予BALB/c裸鼠腹腔注射不同剂量环磷酰胺,72小时后再给予小鼠皮下接种淋巴瘤细胞,观察预处理前后小鼠外周血白细胞数量及体重变化情况,以及肿瘤成模率、急性死亡率等。结果:①组1(NS对照组)、组2(100mg/kg×1d)、组3(125mg/kg×1d)、组4(75mg/kg×2d)预处理后体重较处理前无显著性变化,亦无急性死亡情况发生;而组5(125mg/kg×2d)、组6(200mg/kg×2d)、组7(125mg/kg×3d)、组8(250mg/kg×3d)小鼠体重较预处理前明显减轻,且急性死亡率依次为30%、58.3%、50%、75%;②组1和组2小鼠预处理后72小时外周血白细胞数较处理前无明显差异,同时均未成模;而组3、组4、组5、组6、组7、组8小鼠白细胞较预处理前均显著下降,成模率依次为20%、83.3%、60%、33.3%、50%、25%。结论:使用环磷酰胺75mg/kg连续2天腹腔注射的预处理方案,操作简单,成本低廉,通过观察外周血白细胞数和小鼠体重水平等指标即可初步判断建模情况,同时肿瘤成模率高,毒副作用小,是理想的预处理方案。     

Induction of tolerance in athymic mice with an antigen which is highly immunogenic in euthymic mice.

Adult congenitally athymic (nu/nu) mice were found to be unable to respond to aggregated human γ-globulin (AHGG), the normally immunogenic form of HGG, unless first reconstituted with specific T cells. However, pretreatment of nude mice with AHGG prior to T-cell reconstitution resulted in the induction of unresponsiveness. This state of tolerance was specific since pretreated animals responded normally to the noncross-reacting antigens turkey γ-globulin or DNP-Ficoll. Transfer of spleen cells from nude mice pretreated with AHGG into normal littermates did not significantly affect a subsequent anti-HGG response of the recipients. Conversely, nude mice pretreated with AHGG and reconstituted with normal littermate spleen cells were hyporesponsive to challenge with AHGG. The results of these experiments are discussed in reference to various models for the induction of B-cell unresponsiveness.     

Growth of tumor cells with different sensitivities for murine natural killer cells in young and adult athymic nude mice

Of four tumor cell lines, the murine YAC lymphoma, the human K562 lymphoma, and the human prostatic carcinomas PC3 and PC93, the susceptibility to murine natural killer (NK) cells as well as the tumorigenicity in young (3.5-4 weeks old) and in adult (8-10 weeks old) nude mice were studied. In young nude mice, which exhibited a lower level of NK cell activity than adult nude mice, the formation of solid tumors after inoculation of tumor cell suspensions occurred more frequently and with a shorter time lag than in adult animals. These effects were observed not only with the NK-sensitive YAC cells, but also with the relatively NK-insensitive PC3 and PC93 cells, indicating that also factors other than NK cell susceptibility may influence the growth of tumor cells in nude mice. Therefore, the use of young nude mice may enhance the rate of success of heterotransplantation of human tumors, regardless of the NK cell susceptibility of the tumor cells.     

Cyclophosphamide pretreatment in tumor cryotherapy: A murine model

Following the protocol of Turk and Lagrange for selective potentiation of cell-mediated immunity, a single high dose of cyclophosphamide was given to inbred mice bearing subcutaneous tumors 3 days before cryosurgery. Cyclophosphamide pretreatment caused a rise in the rate of total tumor ablation and local recurrence was delayed. The dose response to tumor size, cyclophosphamide, and freeze parameters indicated that these effects were the result of synergistic rather than additive processes. Instances of metastatic tumor growth and immunologically mediated complications of cryosurgery were also lower when the cryosurgery was accompanied by cyclophosphamide pretreatment.     

Immunotherapy of established murine B cell lymphoma. Combination of idiotype immunization and cyclophosphamide

A murine B cell lymphoma (38C13) was used to study the efficacy of idiotype immunotherapy against established tumors. Immunization of mice with 38C13 tumor-derived Ig, administered after a lethal tumor inoculation, significantly prolonged survival of animals compared to control groups. The efficacy of active immunotherapy was dramatically enhanced when combined with chemotherapy. Cyclophosphamide (100 mg/kg), administered in combination with idiotype immunization to mice bearing 10-day-old, 1 to 2 cm diameter s.c. tumors, resulted in a significant prolongation of survival as compared with either cyclophosphamide or immunization alone and yielded approximately 50% cures. Additional studies combining active immunotherapy with surgical excision of the primary s.c. tumor nodule were less effective than combination chemoimmunotherapy, indicating that reduction of tumor burden was necessary, but not sufficient for effective treatment of established 38C13 lymphoma.     

Chemo-immunotherapy of murine tumors using interleukin-2 (IL-2) and cyclophosphamide

Summary The antitumor effect of interleukin-2 (IL-2), alone and in combination with cyclophosphamide was assessed in mice with established sarcoma (MCA 105, H-2^b), carcinoma (M109, H-2^d) and T lymphoma (PIR-2, H-2^b). Whereas administration of IL-2 alone (5×10⁴–10×10⁴ U, i.p. twice daily, for 4–8 consecutive days) prolonged the survival of mice with the solid neoplasms, it enhanced tumor growth and decreased survival of mice with the lymphoma. In the PIR-2 lymphoma, no IL-2 receptor (TAC) could be detected, nor could we demonstrate IL-2 tumor growth stimulation in vitro. A synergistic therapeutic effect was achieved in mice with the solid tumors, but not in mice with the lymphoma, only when IL-2 was given 1–4 days after cyclophosphamide (100–200 mg/kg). Conversely, administration of IL-2 1–4 days prior to cyclophosphamide resulted, in all three tumor systems, in enhanced tumor growth and in decreased survival as compared with mice receiving cyclophosphamide alone. Similarly, treatment with IL-2 both before and after cyclophosphamide was less efficacious than a single course of IL-2 given after-wards. It is concluded that for maximal therapeutic efficacy, IL-2 should be administered following chemotherapy, and that certain tumors may respond adversely to IL-2 treatment.     

Response of human squamous cell carcinoma xenografts of different sizes to irradiation: relationship of clonogenic cells, cellular radiation sensitivity in vivo, and tumor rescuing units

The relationship of clonogenic cells, cellular radiation sensitivity at tumor control does in vivo, and tumor rescuing units at different tumor sizes was investigated in the human squamous cell carcinoma FaDu growing in NCr/Sed nude mice. The composition of the tumors was determined in single cell suspensions and compared to tumor control data after single-dose irradiation. To avoid the influence of varying oxygen concentrations in the tumors, all irradiations were performed under clamp hypoxia. Nude mice and animals further immunosuppressed by 6-Gy whole-body irradiation were used to assess the immunological effects. The numbers of total cells, cells excluding trypan blue, host cells, and colony-forming cells increased linearly with the weight of FaDu tumors. Comparable results were obtained for cell suspensions prepared from tumors growing in nude of pretreated nude mice. The radiation dose required to control 50% of tumors (TCD50) of different sizes between 36 and 470 mm3 increased from 52.1 to 60.1 Gy when the tumors were maintained in normal nude mice and from 50.8 to 61.3 Gy in whole-body-irradiated mice. The D0 of FaDu cells in vivo was calculated by regression analysis of TCD50 vs the logarithm of the clonogenic cell number, assuming an oxygen enhancement ratio of 3.0. The resultant D0S of 1.1 and 1.2 Gy in vivo correspond well to the radiosensitivity of FaDu cells in vitro determined previously. Assuming the single-hit multitarget model of cell killing and extrapolation numbers between 2 and 20, the mean number of tumor rescuing units would be 10(5) to 10(6) for a 100-mm3 tumor growing in whole-body-irradiated nude mice. Comparison of the number of tumor rescuing units to the estimated number of clonogenic cells does not conflict with the assumption that every surviving clonogenic cell is able to repopulate FaDu tumors after irradiation; however, it seems more likely that more than one clonogenic cells is necessary. The proportion of tumor rescuing units in the clonogenic cell population is independent of tumor size.     

Efficient immobilization technique for enhancement of cellobiose dehydrogenase activity on silica gel

In this study, cellobiose dehydrogenase (CDH) of Phanerochaete chrysosporium ATCC 32629 was immobilized on silica gel for the further application of CDH in the saccharification process of biomass. To prevent the loss of enzyme activity during enzyme immobilization, the pretreatment of CDH was performed by various pretreatment materials before immobilization. When pretreated enzymes were used in immobilization, the activities of immobilized CDH were higher than non-pretreated CDH even in same amounts of immobilized protein. The specific activity of pretreated immobilized CDH with lactose was about two times higher than that of non-pretreated immobilized CDH. Moreover, the pretreated immobilized CDH showed better reusability than non-pretreated immobilized CDH, with 67.3% of its original activity being retained after 9 reuses.     

建立小鼠膀胱肿瘤原位模型的优化方法

目的探讨硝酸银、盐酸、胰酶和乙醇预处理构建鼠膀胱肿瘤的成瘤机制。方法 24G静脉留置针插入膀胱,PBS冲洗后,将小鼠随机分为5组,每组6只:(1)乙醇作用组:22%乙醇0.1 mL保留20 min;(2)胰酶作用组:0.2%胰酶保留30 min;(3)酸碱作用组:0.1 mmol/L HCl 0.1 mL作用15 s后,PBS冲洗,0.1 mmol/L NaOH0.1 mL作用5 s,排空膀胱;(4)硝酸银作用组:0.15 mol/L硝酸银保留10 s;(5)对照组:0.1 mL生理盐水。术后1和24h随机处死每组3只小鼠,摘取膀胱,HE染色观察膀胱黏膜病理变化;戊二醛固定,电镜下观察膀胱黏膜细胞微结构变化;甲苯胺蓝染色,观察膀胱黏膜固有层肥大细胞数目变化;过碘酸-希夫(PAS)染色,观察膀胱黏膜GAG层变化。40只小鼠应用上述前四组预处理因素处理膀胱后,建立膀胱癌原位模型,计算各组成瘤率。结果胰酶和乙醇处理1h后,局部上皮伞状细胞脱落,黏膜下层暴露;酸碱和硝酸银处理组大部黏膜完整性破坏,黏膜下层暴露较多,连续性中断;对照组和实验组间炎症细胞浸润均不表现出统计学差异。24 h后,胰酶和乙醇组可见局部轻度水肿并充血,黏膜完整性恢复较好,细胞间见紧密连接;而酸碱和硝酸银组上皮黏膜薄厚不均一,仍可见部分脱落黏膜。结论利用硝酸银和酸碱预处理膀胱可作为鼠膀胱肿瘤原位模型构建的首选方法。     

促吞噬肽衍生物 T 肽对裸鼠术后残瘤 VEGF 表达的影响

目的：探讨促吞噬肽衍生物T肽抑制裸鼠术后残瘤生长的作用机理。方法：建立MCF-7乳腺癌裸鼠皮下移植瘤术后残瘤模型,观察8mg／kg剂量T肽对残余肿瘤组织的生长情况,并采用免疫组化和Western印迹检测给药后残瘤组织血管内皮生长因子（VEGF）的表达,采用RT-PCR检测不同T肽浓度对血管内皮细胞VEGF基因转录的影响。结果：T肽对MCF-7乳腺癌裸鼠皮下移植瘤术后残瘤生长表现出良好的抑制作用,按照瘤重得出的抑制率为68．2％,按照肿瘤体积得出的抑制率为67．6％,T肽给药组裸鼠残瘤组织中VEGF的表达量较空白对照组明显减少。血管内皮细胞中T肽呈剂量相关性抑制VEGF基因的转录。结论：T肽的抗癌作用与其抑制肿瘤微环境肿瘤组织和血管内皮细胞中VEGF的表达有密切联系,预示着T肽有潜力成为预防术后残瘤生长的抗癌新药。     

Antisense oligonucleotide Elk-1 suppresses the tumorigenicity of human hepatocellular carcinoma cells

In previous studies, we showed that reducing Ets-like protein-1 (Elk-1) expression inhibited protein kinase C alpha (PKC alpha) expression and decreased cell migration and invasion in human hepatocellular carcinoma (HCC). In this study, we have investigated the role of Elk-1 in tumorigenesis. SK-Hep-1 HCC cells were transfected with the ElK-1 antisense oligonucleotide (ODN). In the pretreated cells we detected a reduction of mRNA level using RT-PCR. The inhibitory rate of cell growth was measured by MTT assay. Pretreated-SK-Hep-1 HCC cells were implanted subcutaneously into nude mice to observe the tumor growth and calculate tumor inhibitory rate. The results showed that 5 microM of the antisense ODN Elk-1 suppressed both Elk-1 and PKC alpha production by SK-Hep-1 HCC cells after cationic liposome-mediated transfection, to 8% and 1% of control values, respectively, and the growth of SK-Hep-1 HCC cells was inhibited at 2-5 microM doses of the antisense ODN Elk-1. The control reagent, sense ODN Elk-1, showed no effects. In BALB/nude mice, SK-Hep-1 HCC cells transfected with the 5 microM antisense ODN Elk-1 formed tumors much smaller than those of sense ODN Elk-1 pretreated cells. The maximum inhibitory rate of tumor growth was 80.8+/-12.6% and the tumor formation time was prolonged from 13 to 25 days. These findings suggested the usefulness of antisense ODN Elk-1 as a new reagent for liver cancer therapy.     

Effects of thymus grafts in nude mice transplated with human malignant tumors

The effect of neonatal thymus grafts implanted in nude mice previously transplanted with three different human malignant tumors - an adenocarcinoma of the colon, a malignant melanoma and a Burkitt's lymphoma - were studied. In all immunologically reconstituted animals tumord were rejected. Tumor rejection stated 2-3 weeks after thymus implantation, and was completed after 30-6 weeks. Histological examination of lymphoid tissues showed a correlation between immunological reconstitution and tumor rejection. The rejection process showed a characteristic histologic picture with 3 phases - an early, an intermediate and a late phase - these were similar in the three tumor types examined. The possible mechanisms of reconstitution and tumor rejection are discussed.     

Induction of B-Cell Lymphoma in BALB/c Nude Mice with an Ecotropic, B-Tropic Helper Virus Present in the Murine AIDS Virus Stock

The pathogenicities of the murine AIDS (MAIDS) virus complex (LP-BM5) and ecotropic helper virus (BM5eco) isolated from the complex to BALB/c nude mice were studied to elucidate the possible role of replication-competent helper virus in inducing the monoclonal outgrowth of lymphoid cells. Neither LP-BM5 nor BM5eco was pathogenic in adult BALB/c nude mice. However, B-cell lymphoma developed with a very high frequency when either virus was inoculated into newborn BALB/c nude (nu/nu) mice. The cells from the B-cell lymphoma were easily transplanted into nude mice. These results suggested that ecotropic helper virus in the MAIDS virus complex plays an important role in inducing the monoclonal outgrowth of lymphoid cells under immunodeficient conditions caused by defective virus.     

贝伐单抗对ALA—PDT诱导的新生血管形成和胶质瘤生长的影响

探讨贝伐单抗对低剂量5-氨基乙酰丙酸（5-Aminolevulinicacid,ALA）介导的光动力学疗法（photodynamic therapy,PDT）诱导的脑组织新生血管形成和U87脑胶质瘤生长的影响。通过将裸小鼠随机分为对照组、ALA．PDT预处置组（ALA：2．3×10-3mol／kg,能量密度：10J／cm2）、贝伐单抗预处置组（1．6×10-5mol／kg）和联合预处置组（ALA—PDT＋贝伐单抗）,并接受相应处置。第10d,检测PDT照射及相应区域内新生血管形成和VEGF表达并种植U87脑胶质瘤细胞,21d后观察肿瘤体积。与对照组比较,低剂量ALA-PDT预处置后新生血管增多、VEGF表达增高,肿瘤体积增大,这些变化在联合预处置组被抑制;贝伐单抗预处置组的血管形态和VEGF表达虽无明显变化,但肿瘤体积减小。研究结果表明低剂量ALA-PDT可通过刺激VEGF表达诱导照射区新生血管形成,这种微环境的改变有利于U87胶质瘤细胞生长,但这些作用可被贝伐单抗所抑制。     

Dual-modality monitoring of tumor response to cyclophosphamide therapy in mice with bioluminescence imaging and small-animal positron emission tomography

The purpose of this study was to noninvasively monitor the therapeutic efficacy of cyclophosphamide (CTX) in a mouse model by dual-modality molecular imaging: positron emission tomography (PET) and bioluminescence imaging (BLI). Firefly luciferase (fLuc) transfected HCC-LM3-fLuc human hepatocellular carcinoma cells were injected subcutaneously into BALB/c nude mice to establish the experimental tumor model. Two groups of HCC-LM3-fLuc tumor-bearing mice (n = 7 per group) were treated with saline or CTX (100 mg/kg on days 0, 2, 5, and 7). BLI and (18)F-fluorodeoxyglucose ((18)F-FDG) PET scans were done to evaluate the treatment efficacy. CTX induced a 25.25 ± 13.13% and 35.91 ± 25.85% tumor growth inhibition rate on days 9 and 12 posttreatment, respectively, as determined by BLI. A good linear correlation was found between the tumor sizes measured by caliper and the BLI signals determined by optical imaging (R(2) = .9216). (18)F-FDG imaging revealed a significant uptake reduction in the tumors of the CTX-treated group compared to that in the saline control group (5.30 ± 1.97 vs 3.00 ± 2.11% ID/g) on day 16 after CTX treatment. Dual-modality molecular imaging using BLI and small-animal PET can play important roles in the process of chemotherapy and will provide noninvasive and reliable monitoring of the therapeutic response.     

Anti-invasive and anti-metastatic effect of lysine oxidase from Trichoderma sp. in vitro and in vivo]

A new fungal strain, Trichoderma sp., discovered in Moscow, produces the antitumor enzyme, lysine-oxidase, which demonstrates an anti-invasive effect in vitro and anti-metastatic activity in vivo. Maximal inhibition of the in vitro invasion of MM1 clone cells was obtained when the tumor cells were pretreated with 2.5 mU/ml of lysine-oxidase; the pretreatment caused a 1.9-times reduction in cell growth and a 1.6-times reduction in the invasive capacity. We studied its anti-metastatic effect on the spreading Lewis lung carcinoma (3LL) in mice from which the primary tumor had been removed. The administration of the enzyme (50 U/kg, i.v.) significantly decreased not only the extent but the number of lung metastases, as compared with the untreated mice. In addition to that, the lysine-oxidase treatment considerably increases the life-span of mice from which the primary tumor had been removed (200 days after 3LL implantation, lysine-oxidase treatment caused surviving of 50% mice in experimental group).     

Anticancer effects of a plant lignan 7-hydroxymatairesinol on a prostate cancer model in vivo

Clinical intervention studies and experimental studies with lignan-rich diets suggest that lignans may have inhibitory effects on prostate cancer, but no clinical or experimental studies with purified lignans have been published. The purpose of this study was to investigate the effect of a plant lignan 7-hydroxymatairesinol (HMR) on LNCaP human prostate cancer xenografts in athymic mice. Athymic nude male mice were injected subcutaneously with LNCaP cells. Starting 3 days after tumor cell injections, a control diet or a control diet supplemented with 0.15% or 0.30% of HMR was administered to mice and the tumor take rate and growth was observed for 9 weeks. HMR diet inhibited the growth of LNCaP tumors. Mice treated with HMR had smaller tumor volume, lower tumor take rate, increased proportion of nongrowing tumors, and higher tumor cell apoptotic index compared with controls. Furthermore, the cell proliferation index was reduced in mice receiving the 0.30% HMR diet compared with mice receiving the control diet. Our results suggest that dietary HMR started at the early phase of the tumor development inhibits the growth of the LNCaP human prostate cancer xenografts in athymic male mice.     

Suppression of tumorigenicity of human hepatocellular carcinoma cells by antisense oligonucleotide MZF-1

Our previous studies have found that reducing expression of myeloid zinc finger-1 (MZF-1) inhibited protein kinase C alpha (PKCalpha) expression and decreased cell migration and invasion in human hepatocellular carcinoma (HCC). In this study, we further investigated the role of MZF-1 in tumorigenesis. The SK-Hep-1 HCC cells were transfected with the antisense oligonucleotide (ODN) of MZF-1. The pretreated cells was then detected the mRNA and protein levels by RT-PCR and western blotting, and the cell growth was assayed by MTT. Meanwhile, the pretreated-SK-Hep-1 HCC cells were implanted subcutaneously into nude mice to observe the tumor growth and calculated tumor inhibitory rate. The results showed that, at the dosage of 5 microM, the antisense ODN MZF-1 suppressed both MZF-1 and PKCalpha productions by SK-Hep-1 HCC cells after cationic liposome-mediated transfection, to 15% and 30% in control cultures of 0 microM dosage, respectively. The growth of SK-Hep-1 HCC cells was inhibited by the 2-5 microM doses of the antisense ODN MZF-1, whereas the control reagent, the sense ODN MZF-1, showed no effects. In BALB/nude mice, SK-Hep-1 HCC cells pretreated with the 5 microM antisense ODN MZF-1 formed tumors much smaller than the cells with sense ODN. The mean of inhibitory rate of tumor growth was 71.2 +/- 8.6%, and the tumor formation time was prolonged from 14 days to 26 days. These findings suggested the usefulness of antisense ODN MZF-1 as a new reagent for cancer therapy.