Distribution of and physiologic factors that affect 131I-antiferritin tumor localization in experimental hepatoma

Polyclonal ¹³¹I rabbit anti-rat ferritin localizes in the H-4-II-E hepatoma model. The effect of tumor size, vascularity, and ferritin content on tumor localization was examined. The extravascular and intravascular quantity and location of ¹³¹I non-specific IgG and ¹³¹I-antiferritin IgG in tumors were determined by gamma counter analysis of tissue samples and autoradiography. Separate groups of 8–10 tumor bearing rats with 0.6–1 g, 1–3 g, 4–8 g, 8–14 g, and > 14 g tumors were injected with 500 μCi (200 μg) of ¹³¹I non-specific IgG or ¹³¹I-antiferritin. Tumor targeting with antiferritin occurred maximally in primary or metastatic lesions less than 1 g in size. Decreased localization occurred with increasing tumor size and no localization took place in tumors > 8 g in size. This finding is independent of administered dose because increasing the amount of injected antiferritin from 2- to 10-fold did not increase the antiferritin/normal IgG targeting ratio in any group of tumors > 4 g. The quantity and physical characteristics of the tumor vasculature may in part explain selective tumor localization. Tumor vascularity per gram as measured by ⁵¹Cr labeled erythrocytes decreased as tumor size increased. Decreased localization was evident in the necrotic portions of large tumors. Autoradiography of tumor sections revealed that most of the ¹²⁵I-IgG activity is deposited perivascularly with decreased deposition of antibody in necrotic areas of tumors and at increasing distance from the lumen of vessels. These findings have clinical importance since this non-homogeneous distribution of antibody could result in the delivery of low doses of radiation to large necrotic areas of tumors. These results help to demonstrate some of the complex physiologic factors that affect tumor localization and antibody distribution.     

Selective tumor localization in experimental hepatoma by radiolabeled antiferritin antibody

The in vivo localization of 131I-radiolabeled antiferritin and normal IgG in the H-4-II-E rat hepatoma model was investigated by serial necropsy. Groups of 14 to 18 animals were injected with 500 microCi (200 micrograms) of normal and antiferritin IgG. The total dose from the nonpenetrating beta radiation was calculated for tumor and normal tissue, and expressed as a targeting ratio of antiferritin to normal IgG for each organ studied. The results demonstrate 2.9 times greater dose deposition in tumors of animals treated with 131I-antiferritin than with 131I-normal IgG. 131I-antiferritin deposited equivalently in primary tumors and metastatic lesions of similar size. The specific binding in tumors could be competitively inhibited by the addition of unlabeled antiferritin but not unlabeled normal IgG. Specific targeting with 131I-antiferritin comparison to 131I-normal IgG did not occur in any normal tissue. There was considerable variation in the dose deposition in different normal tissues.     

Yttrium-90 and iodine-131 radioimmunoglobulin therapy of an experimental human hepatoma

Therapeutic trials were performed on the HepG2 human hepatoblastoma implanted s.c. in the athymic nude mouse. Animals were treated with polyclonal and monoclonal antiferritin and control antibodies labeled with either iodine-131 (131I) or yttrium-90 (90Y). Administration of 400 muCi of 131I-labeled polyclonal antiferritin or 300 muCi of 90Y-labeled polyclonal antiferritin significantly increased survival (P less than 0.001). There were no tumor cures with radiolabeled polyclonal antibody therapy. Animals treated with 200 or 300 muCi of 131I-labeled monoclonal antiferritin (QCI054) did not show increased survival compared to controls. Although 400 muCi of 131I-labeled QCI significantly prolonged survival, treatment resulted in no long-term survivors. Monoclonal antiferritin labeled with 90Y significantly prolonged survival of animals (P less than 0.001) at doses of 100, 200, or 300 muCi compared with untreated controls. Fifty % of the animals treated with 200 muCi and 75% of the animals treated with 300 muCi showed no evidence of disease at 140 days following treatment. Four hundred muCi of 90Y-labeled QCI proved toxic to the animals. Increased survival was accompanied by a decrease in tumor mitotic rate and increase in cellular polymorphism as determined by pathological examination. The radiation dose absorbed in the tumor correlated directly with tumor response following treatment. The absorbed dose in tumors for complete decay of the isotope ranged from 165 and 330 cGy at the periphery and center of small tumors for an administered activity of 200 muCi of 131I-labeled polyclonal antiferritin, to 7,573 and 12,400 cGy for 300 muCi of 90Y-labeled monoclonal antiferritin QCI.     

Ferritin involved in the tumor development

Ferritin is a kind of glycoprotein synthesized by the liver. Being the main form of stored iron in the body, it plays an important role in the iron balance. When the iron level in the body increases, ferritin can intake and storage the iron avoid-ing the cytotoxicity caused by the high level of intracellular iron;when body needs more iron, ferritin can release iron at any time. Recent studies have found that tumor tissue can synthesize and secrete ferritin. Ferritin levels increase in liver cancer, lung cancer, pancreatic cancer, breast cancer, leukemia and other malignancies. In this paper, we reviewed the relationship between the changed ferritin and the malignancy disease.     

Deoxycytidylate aminohydrolase activity in the Novikoff hepatoma is dependent on the localization of the tumor

The activity of deoxycytidylate aminohydrolase, a pivotal enzyme for pyrimidine biosynthesis in mammalian tissue, is 100x greater in the Novikoff hepatoma harvested from the intraperitoneal cavity than in the same tumor excised from either subcutaneous or intramuscular sites. The increased enzyme activity in the intraperitoneal tumor is not due to an increase in protein synthesis, since there are no significant differences in enzyme activity between normal liver, and either the subcutaneous or intramuscular hepatomas. Evidence is presented which indicates that deoxycytidylate aminohydrolase activity, and the expression of alternate pathways of pyrimidine biosynthesis in the Novikoff hepatoma, is dependent on the localization of the tumor within the host.     

Creation of porcine liver tumor using human hepatoma cell lines: experimental study

BACKGROUND: Pig is an ideal animal to study the efficacy of surgical and ablative treatment options available for the treatment of liver tumors. But there is no liver tumor model available in pig. This experiment was carried out to create liver tumors in the pig using immunosuppression and portal tolerance. MATERIAL AND METHODS: Two mini pigs (specific pathogen free) were immunosupressed using cyclosporine, azathioprine and prednisolone immunotherapy. Human hepatoma cell line (HepG2) was delivered into the liver through portal vein injection. Engraftment of the tumor cell was monitored using regular measurement of serum alfa- fetoprotein level (AFP). Pigs were sacrificed at the end of six weeks to confirm any evidence of tumor in the liver. RESULT: Although there was rise in serum AFP level in the first week, tumor cells did not engraft in the liver and there was no evidence of liver tumor at the end of experiment. CONCLUSION: Effect of immunosuppression and portal tolerance does not prevent rejection of human hepatoma cells by porcine immune system.     

Ferritin in neuroblastoma. Impact of tumor load and blood transfusions

Serial serum ferritin (SF) levels were measured in 36 patients with neuroblastoma seen at Memorial Sloan-Kettering Cancer Center (MSKCC) between January 1981 and December 1982. The significance of the associations among SF, stage and extent of disease, number of blood transfusions, liver function, serum iron (Fe), total iron-binding capacity (TIBC), and transferrin saturation was investigated. Although a dominant statistical correlation was found between SF and number of blood transfusions, the results suggest that amount of disease contributes to increasing SF levels. Serum ferritin levels increased on average in a linear fashion with number of blood transfusions in patients free of disease or with minimal disease. In patients with bulky disease, this increase was exponential (p value less than 0.01). Application of a reverse hemolytic plaque assay to the analysis of ferritin secretion by cells demonstrates that tumor cells do secrete ferritin in vitro.     

Relationship of tumor hypoxia and response to photodynamic treatment in an experimental mouse tumor

The relationship between tumor oxygenation and the effectiveness of photodynamic therapy (PDT) was studied in vitro and in vivo using the RIF mouse tumor model. The oxygen dependence of photodynamic inactivation of RIF cells, which had been exposed to 25 mg/kg porphyrin (dihematoporphyrin ether) in vivo, isolated and illuminated in vitro, was determined. No cell kill was achieved under anoxic conditions, full effect was reached at 5% O2, and the half value of cell inactivation was found to be at 1% O2. Tumor hypoxia was assessed after in vivo gamma-irradiation of control and PDT-treated tumors by in vitro clonogenic assay of cell radiosensitivity. In vitro control experiments established that the radio-sensitivity of PDT-surviving RIF cells was identical to that of untreated control cells. RIF tumors of treatment size (80-120 mg) contained no detectable hypoxic tumor cell fraction. PDT treatment consisting of i.p. injection of 10 mg/kg dihematoporphyrin ether 24 h prior to 45 J/cm2 of 630 nm light, rendered approximately 9% of tumor cells severely hypoxic within 10 min of treatment time. An illumination period of 30 min (135 J/cm2) induced a hypoxic tumor cell fraction of 17%, which increased to 47% within 1 h posttreatment. Despite the prompt induction of tumor hypoxia during PDT light treatment, the tumors proved highly curable (81% cures) under the present treatment conditions (depilation of tumor area, 10 mg/kg dihematoporphyrin ether i.p., 135 J/cm2). Considering the reduced effectiveness of photodynamic cell kill at low oxygen concentrations, the rapid induction of tumor hypoxia by PDT itself, and the high tumor cure rate, it has to be concluded that in the RIF tumor hypoxic tumor cells are inactivated by a mechanism other than direct photodynamic cytotoxicity, and are thus not limiting to PDT tumor response.     

铁蛋白为肿瘤诊治提供新的视角

铁既是生命所必须,又与肿瘤的发生、发展密切相关。铁在氧化态和还原态之间循环导致自由基形成,由此产 生包括肿瘤形成在内的有害作用。异常铁代谢增加肿瘤发病风险,促进肿瘤的生长。铁蛋白是一种由肝脏合成的糖蛋白, 在铁的平衡中起至关重要的作用。铁蛋白通过将铁摄入并贮存,避免了细胞内高浓度游离铁对细胞的毒性作用。血清铁蛋 白是反映体内铁储备的主要指标,大多数肿瘤患者中铁蛋白的表达增加。铁蛋白通过参与抗氧化损伤、血管生成、免疫抑制、 促进细胞增殖等促进肿瘤的发生、发展。高表达铁蛋白的患者生存期短,提示其可作为评估肿瘤预后的指标。下调铁蛋白 的表达不仅能够抑制肿瘤增殖,还能增加化疗药物的敏感性,提示其在抗肿瘤治疗中的潜在前景。许多新发现让我们重新 认识铁蛋白,但是仍需要更深入的研究来继续揭示铁蛋白的新功能。本文拟通过阐述铁蛋白促进肿瘤增殖机制的最新研究 及其与肿瘤预后的相关性,对铁蛋白在抗肿瘤治疗中的临床意义以及进一步应用进行综述。     

Pharmacokinetics and tumor localization of 131I-labeled anti-tenascin monoclonal antibody 81C6 in patients with gliomas and other intracranial malignancies

We previously have reported that radioiodinated anti-tenascin monoclonal antibody 81C6 exhibits therapeutic potential against both s.c. and intracranial human glioma xenografts in athymic mice and rats. Herein we report the selective tumor localization of 131I-labeled 81C6 in patients with gliomas and other intracranial malignancies. Nine patients were simultaneously administered 5-50 mg of 131I-labeled 81C6 and 1-2 mg of 125I-labeled 45.6, an isotype-matched control monoclonal antibody. The blood clearance half-time for 81C6, normalized to that of 45.6 in the same patient, appeared to decrease with 81C6 protein dose. Gamma camera images obtained at 1 to 3 days exhibited increased uptake of 131I in regions corresponding to tumor with varying degrees of contrast to surrounding normal brain. Biopsy specimens of tumor and normal brain were obtained and analyzed histologically for tumor content. The average uptake of 81C6 in tumor ranged from 0.6 to 4.3 x 10(-3)% of the injected dose per gram. In patients receiving 20-50 mg of 81C6, the average tumor-to-normal-brain ratio was 25:1 with ratios as high as 200:1 seen in some samples. Localization indices were calculated by normalizing the uptake of 81C6 per gram tumor to the uptake of 81C6 per gram blood and dividing by the same ratio for 45.6 control monoclonal antibody. Localization indices for muscle and brain were about 1, in contrast to up to five for tumor. These studies demonstrate that the tumor uptake of 131I-labeled 81C6 in patients with gliomas and other intracranial malignancies is due to specific processes.     

Photofrin II as an efficient radiosensitizing agent in an experimental tumor.

BACKGROUND AND OBJECTIVE: The use of ionizing irradiation as radiation therapy (RT) for tumor treatment represents a well-established method. The use of photodynamic therapy (PDT), especially with Photofrin II, for tumor treatment is also known. Chemical modifiers enhancing the action of radiation therapy are well known and widely used in medicine. None of these compounds, however, is a selective radiosensitizer. MATERIALS AND METHODS: Several series of animal experiments were performed. The highly differentiated human bladder cancer cell line RT4 was implanted subcutaneously in nude mice. The mice were injected 10 mg/kg Photofrin II and irradiated with 5 Gy. RESULTS: Photofrin II has proved to be a chemical modifier of ionizing irradiation, enhancing the tumor doubling time (tumor growth) from 6.2 to 10.9 days in the control group with the use of irradiation and injection of porphyrin. CONCLUSION: Photofrin II shows a high activity as radiosensitizer and, in the future, can be used as a selective radiosensitizer for tumor treatment with ionizing radiation.     

Ganglioside composition of an experimental mouse brain tumor

The ganglioside composition of an experimental ependymoblastoma was examined in C57BL/6 mice. This tumor was produced by Dr. H. Zimmerman in 1949 from methylcholanthrene implantation in the brain and has been maintained in serial transplants through many generations. The influence of tumor environment on ganglioside composition was determined by studying the tumor growing intracerebrally and s.c. (over the skull and in the flank). The ganglioside composition of this tumor is markedly different from that of adult mouse brain. The total ganglioside sialic acid content (micrograms/100 mg dry weight) of the tumor growing in the cerebrum, s.c. over the skull, and in the flank was 70.4 +/- 3.8 (N = 3), 66.8 (N = 2), and 41.7 +/- 0.7 (N = 3), respectively. These values are about 10-fold lower than the ganglioside content of normal mouse cerebrum. This tumor contained a significant amount of N-glycolyneuraminic acid (NGNA). Histological analysis revealed two basically different cell types. The predominant cell type is densely packed and poorly defined in shape, whereas the minor cell type is less densely packed and fibroblastlike in shape. GM3, which migrates as double bands on thin-layer chromatography, is the predominant ganglioside of this tumor in all three regions of growth. Also present in all regions are gangliosides NGNA-GM3 and GM1. Significant amounts of GD1a, GD1b, GT1b, and GQ1b are present only in the cerebral tumor. These gangliosides therefore represent contaminants from normal brain tissue surrounding the tumor and are not native to the tumor. Ganglioside GD3, however, is a minor component of the tumor. Using a thin-layer chromatography-immunostaining method with anti-GA1 antibody, we found significant amounts of ganglioside with a GA1 oligosaccharide backbone migrating near GD3 and GD2. This tumor is similar to other neural tumors in having elevated amounts of GM3 and reduced amounts of total ganglioside and polysialogangliosides but is unique in having a high content of NGNA-containing gangliosides. The possible origin of the NGNA-containing gangliosides is discussed.     

Dosimetry of 131I-labeled anti-ferritin in hepatoma: a model for radioimmunoglobulin dosimetry

Dosimetric studies are reported for four hepatoma patients treated with ¹³¹I-labeled anti-ferritin following combination radiation and chemotherapy. Administered activities of radiolabeled antibody ranged from 93 to 157 mCi. Studies included liver and tumor volume calculations from sequences of computerized axial tomographic (CAT) scan slices, in-vivo gnantitation of radiolabeled antibody in the liver and tumor, determination of kinetic parameters of radioimmmioglubulin for liver, tumor, and the total body, and computation of dose rates (rad/boor) and dose (rad) for these tissues. Tumor volumes for these patients prior to the administration of radiolabeled antibody ranged from 370 to 920 cm³ and liver volumes from 900 to 1980 cm³. In-vivo quantitation, carried out 4 to 8 days following infusion of ¹³¹I-labeled anti-ferritin, demonstrated tumor-to-liver ratios of about 2:1 for the deposition of radioimmunoglobuBn in these tissues. Mean values of the effective half-life for radiolabeled antibody in the liver and tumor were 7.4 days and for total-body activity 3.6 days, respectively. For the four patients, the calculated ¹³¹I radiation dose for tumor tissue ranged from 1500 to 2200 rad, for liver tissue from 400 to 1000 rad, and for total-body irradiation (TBI) from 110 to 220 rad.     

131I-angoistatin对H22肝癌小鼠的治疗作用

目的:研究肿瘤血管抑制剂血管抑素和放射性核素131I以及两者联合对H22肝癌小鼠的抑瘤作用。方法:选择40只C57雄性小鼠,分别以每只0.20ml（含H22肝癌细胞2.8×106个）接种于小鼠右后肢根部腹侧皮下,待移植瘤长至直径约10mm时,开始进行干预实验。全部小鼠随机分为4组,分别经尾静脉注射AS(12.5mg／kg)、131I-AS(含131I 10MBq、AS 12.5mg／kg)、131I（10MBq)和生理盐水各0．2ml,分别于3、6、10、14天测量肿瘤体积(肿瘤体积V=ab／2,a、b分别为肿瘤的最大径和最小径),以生理盐水组作为对照组,计算各治疗组的抑瘤率,抑瘤率=(对照组V-实验组V）／对照组V×100％。结果:在治疗结束时,对照组与三个实验治疗组肿瘤体积分别是:NS组（6670±23）mm3、131I-AS组（1979±31）mm3、131I组（5219±19.6）mm3、AS组（3849±11.9）mm3。与对照组相比各治疗组均有明显的抑瘤效应,其中131I-AS组抑瘤效果明显。结论:131I和AS以及131I-AS均可抑制肿瘤的生长,其中131I与AS两者联合对H22荷瘤鼠具有明显的抗肿瘤协同效应,差异具有统计学意义。     

Gangliosides influence angiogenesis in an experimental mouse brain tumor.

Gangliosides are sialated glycosphingolipids present on the plasma membranes of all vertebrate cells. Tumors shed gangliosides into the extracellular microenvironment, which may influence tumor-host cell interactions. We have investigated the role of gangliosides on the growth and angiogenesis of the EPEN experimental mouse brain tumor. EPEN cells express only ganglioside G(M3), and the solid tumors formed in vivo are sparsely vascularized with extensive necrosis. We stably transfected the EPEN cells with the cDNA for N-acetylgalactosaminyl transferase, a key enzyme for the synthesis of complex gangliosides. In addition to G(M3), the transfected cell line (EPEN-GNT) expressed complex gangliosides G(M2), G(M1), and G(D1a). The EPEN-GNT tumor was more densely vascularized with less necrosis and grew more rapidly than the nontransfected EPEN or mock-transfected (EPEN-V) control tumors. Also, VEGF gene expression was higher in the EPEN-GNT tumor than in the control tumors. The synthesis of complex gangliosides in the EPEN-GNT tumor cells also stimulated vascularization in an in vivo Matrigel assay for angiogenesis. These results indicate that the ratio of G(M3) to complex gangliosides can influence the growth and angiogenic properties of the EPEN experimental brain tumor and are consistent with previous findings in other systems. We conclude that gangliosides may be important modulators of brain tumor angiogenesis.     

Regional chemotherapy in an experimental model of Wilms' tumor in rats

Summary A s. c. experimental model of Wilms' tumor in rats was used to compare the effects of intratumoral treatment with vincristine plus actinomycin D to i.v. treatment with these chemotherapeutic drugs. The Wilms' tumor model is a fast-growing solid tumor that has been shown to be resistant to traditional clinical treatment procedures used for Wilms' tumor in man. Injection of the chemotherapeutic drugs directly into the tumor mass was found to be more effective than i.v. therapy in causing long-term remission of the tumor. Intratumoral therapy was also less toxic to the animals than i.v. therapy when measured by post-treatment survival rates and weight loss during the 1st week following treatment. However, intratumoral treatment caused an initial fibrosis of the tumor tissue, which resulted in a slower rate of absorption of the resultant fibrotic tumor mass than was seen in tumors treated i.v. Also, intratumoral injection resulted in necrosis of the overlying skin, which healed as the fibrotic tumor tissue was absorbed. Intratumoral treatment of a cervical tumor was found to cause the remission of a second major tumor mass located at some distance from the initial injection (i.e., in the lumbar region). No significant benefits were noted when dimethylsulfoxide (DMSO) was used in place of aqueous mannitol as a vehicle to deliver the chemotherapeutic agents. There was a significant correlation between the drug dose-to-tumor-size ratio (D/T ratio) and the effectiveness of the chemotherapy. When this ratio was high enough, a single treatment with a combination of vincristine and actinomycin D usually resulted in total remission of the experimental Wilms' tumor in response to either intratumoral or i.v. therapy.     

小鼠肝癌休眠模型的建立

目的：建立小鼠肝癌休眠模型并验证休眠细胞的存在。方法：30只昆明种小鼠均右侧腋下接种1×106个H22腹水型肝癌细胞,常规喂养2周,第15天选择表皮肿瘤直径〉0.5cm的小鼠,进行姑息性手术,将肉眼可见肿瘤组织全部切除。手术后的小鼠再常规喂养8周,如接种处未见肿瘤组织生长,即认为肝癌小鼠休眠模型建立成功（按照平均寿命折算,小鼠生存期8周,即相当于人类寿命5年）。其后模型小鼠分为复发对照组和复发实验组,复发对照组小鼠常规喂养;复发实验组模型小鼠给予连续外伤刺激。6周后处死全部模型小鼠,接种部位取材,组织固定和HE染色观察肿瘤再生成情况确定休眠细胞的存在。结果：肝癌细胞接种于小鼠并行手术后,有20%小鼠成瘤,80%处于休眠状态。复发实验组给予连续外伤刺激6周后,100%小鼠成瘤,而复发对照组只有8.3%,两组差异有统计学意义,P=0.000。结论：本方法成功建立了小鼠肝癌休眠模型,并用外伤刺激引起肝癌休眠细胞增殖,验证了休眠肿瘤细胞在体内的存在。     

Biodistribution and localization of iodine-131-labeled metuximab in patients with hepatocellular carcinoma

PURPOSE: Radioimmunotherapy may improve the outcome of hepatocellular carcinoma (HCC) patients by delivering targeted radiation to liver lesion tissue while relatively sparing nontarget tissues. This study was designed to observe the biodistribution, localization and imaging characteristics of 131I -labeled Metuximab in 24 patients with HCC to determine the diagnostic and therapeutic potential of this antibody. METHODS: Twenty-four HCC patients were randomly divided into three groups to receive 18.5, 27.75 and 37 MBq/kg of 131I-labeled Metuximab per kilogram of body weight, respectively. 99mTc-sodium phytate was administered intravenously and the single photon emission computed tomography (SPECT) scanning was performed. After 48 h, 131I -labeled Metuximab was injected by hepatic artery intubation, and SPECT scan performed at 7 d. The percentage of absorbed 131I (%ID) and the time-dependent 131I tumor:nontumor tissue (T/NT) ratios were calculated at 12, 48, 96 and 192 h after injection. RESULTS: The positive Imaging result of MAb scanning in 24 patients showed that the iodine 131 conjugated to Metuximab was apparently accumulated more in hepatoma. Biodistribution studies of 131I-Metuximab in trial I demonstrated that the comparable % ID uptake in tumor (with a T/NT ratio at 12, 48, 96 and 192 h) to that in such normal organs, as thyroid, heart, lung, spleen and intestines were all more than one. The optimal imaging time for the highest T/NT ratio in liver was at 192 h. CONCLUSION: 131I-labeled Metuximab could deliver relatively selective radiation to tumor tissues and may have potential efficacy in relieving hepatocellular carcinoma.