Cyclophosphamide pretreatment in tumor cryotherapy: A comparison with alternative drugs

The method of Turk and Lagrange for modulating immune responses in favor of the cell-mediated effector arm by using single high doses of cyclophosphamide 3 days before antigen has previously been shown to cause decreased rates of local tumor recurrence when adapted as an adjunctive therapy to cryosurgery in a murine model. This series of experiments compares cyclophosphamide, azathioprine, and methotrexate against cryosurgery alone in the same therapeutic protocol. Only cyclophosphamide gave enhanced numbers of cures; azathioprine caused an increase in metastases arising concurrently with local tumor recrudescence.     

Enhancing tumor implantation and growth rate of Ramos B-cell lymphoma in nude mice

The ability of a human B-cell lymphoma cell line to grow subcutaneously as tumors in nude mice was investigated. The effect of pretreating mice with cyclophosphamide or whole-body irradiation (WBI) was compared with no pretreatment of the mice. Both methods of pretreatment resulted in a higher tumor implantation rate, compared with that for non-pretreated controls. In mice that underwent WBI-pretreatment, a tumor implantation rate of 100% was observed, whereas mice pretreated with cyclophosphamide had a tumor implantation rate of 80%. In non-pretreated control mice, an implantation rate of only 50% was observed. Three weeks after injection, tumor size was significantly larger in mice of the pretreated groups, compared with that in mice of the group that did not receive pretreatment. Furthermore, particularly in the group pretreated with WBI, the tumors grew more synchronously, compared with tumors in the control group. Results of this study indicate that pretreatment with cyclophosphamide or WBI improves the tumor implantation rate of Ramos cells in nude mice, providing a workable animal model for studying human B-cell lymphoma.     

Enhancement of artificial lung metastases in mice caused by cyclophosphamide

Summary The capacity of IV injected fibrosarcoma cells to form metastatic nodules in the lungs of corresponding syngeneic CBA mice was enhanced by pretreatment of tumor cell recipients with cyclophosphamide. The effet depended upon the dose but not upon the injection route of cyclophosphamide. The enhancement of lung-colony formation lasted for about 10 days after injection of the drug, with its maximum at day 1. Cyclophosphamide was also effective in whole body-irradiated and TIR mice. Its effect, however, was abolished to a great extent by reconstituting mice with nonseparated or nonadherent spleen and bone marrow cells from either normal or TIR mice. Lymphoid cells from CY-treated mice, however, had no such reconstitutive capacity. These observations imply that the cyclophosphamide-induced enhancement of tumor metastasis formation was partly due to nonimmunologic factors and partly due to suppression of non-T lymphocytes.     

Basic studies of cryochemotherapy in a murine tumor system

The combined effect of cryosurgery and anticancer drugs (cryochemotherapy) was studied in an experimental B16 melanoma/BDF1 tumor system. Vascular volume and vascular permeability after cryosurgery of normal skin and the tumor were measured by using 51Cr-labeled red blood cells and 125I-labeled serum albumin. The vascular volume and vascular permeability of both the normal vessels and the tumor vessels greatly increased immediately after cryosurgery, and their vascular volume decreased to less than the normal level within a few hours. However, the tumor vessels showed less dilatation and increase in permeability than the vessels of normal tissue. There was a difference in functional characteristics in response to cryoinjury between the normal vessels and the tumor vessels. The anticancer drugs, peplomycin and adriamycin, were administered intraperitoneally in combination with cryosurgery. When peplomycin was administered 5 min, 1 hr, and 3 hr after cryosurgery, the drug concentration in the frozen tumor was higher than that in the untreated tumor. But when administered 1 hr before cryosurgery, peplomycin was not trapped in the tumor. Trapping of adriamycin was not observed after the same treatment. In cryochemotherapy, it is necessary to administer the appropriate drug at the appropriate time. However, the trapping of the anticancer drug results in a high concentration and lasts for a long time, so that cryochemotherapy is expected to be a new mode of cancer therapy, particularly as a multidisciplinary treatment for cancer.     

不同剂量朱砂七总蒽醌对H22荷瘤小鼠免疫功能及抗氧化能力的影响

目的:探讨不同剂量朱砂七总蒽醌对H22荷瘤小鼠免疫功能及抗氧化能力的影响。方法:选取清洁级昆明小鼠60只,按照随机数字表法分为正常对照组、H22荷瘤组、环磷酰胺组、低剂量组、中剂量组、高剂量组,每组各10只。除正常对照组外,其余5组小鼠建立H22荷瘤小鼠模型。低剂量组、中剂量组、高剂量组分别给予0.3 g/kg、0.6 g/kg、1.2 g/kg的朱砂七总蒽醌悬浊液干预,环磷酰胺组给予0.02 g/kg的环磷酰胺干预,正常对照组和H22荷瘤组给予等剂量的1%的羧甲基纤维素钠干预。比较各组小鼠的肿瘤体质量、抑瘤率、T淋巴细胞亚群以及血清超氧化歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)、丙二醛(MDA)、乳酸脱氢酶(LDH)水平。结果:环磷酰胺组、高剂量组的肿瘤体质量低于低剂量组,抑瘤率高于低剂量组,差异具有统计学意义(P0.05)。高剂量组的CD4+、CD4+/CD8+均高于环磷酰胺组、低剂量组、中剂量组,CD8+低于环磷酰胺组、低剂量组、中剂量组,差异均有统计学意义(P0.05)。高剂量组血清SOD、GSH-Px水平高于其他5组,MDA、LDH水平低于H22荷瘤组、低剂量组、中剂量组,差异均有统计学意义(P0.05)。结论:朱砂七总蒽醌具有明显的抗肿瘤作用,可增强小鼠的免疫功能和抗氧化能力,且具有剂量效应。     

Late appearance of resistance to tumor rechallenge following cryosurgery: A study in an experimental mammary tumor of the rat

Resistance to tumor challenge following surgical and cryosurgical eradication of the tumor was studied, using an experimental mammary tumor of the rat, MRMT-1. It was revealed that rejection rate of the challenged tumor increased gradually following cryosurgery and reached its peak at 10 weeks after cryosurgery. No such phenomenon was observed after surgical excision of the tumor. Decreased incidence of lymph node metastases and decreased tumor weights in “take” cases also suggested an increased immunological activity against the tumor at 10 weeks after cryosurgery.     

Cryosurgery and rhTNF-α play synergistic effects on a rat cortex C6 glioma model

Glioma, a type of brain tumor originating from glioma cells, varies widely in aggressiveness and causes serious symptoms, but the treatments are limited. Studies have shown that cryosurgery has multiple effects on tumor treatments, and administration of human tumor necrosis factor-alpha (rhTNF-α) arguments the anti-tumor effect of cryotherapy in breast and prostate cancers. To test the hypothesis that cryosurgery and rhTNF-α play synergistic effects against brain tumors, we established a brain glioma model on rat cortex regions following different treatments: the G1 group was sham-operated; the G2 group was treated with cryosurgery; the G3 group was treated with rhTNF-α; and G4 group received combined treatment with cryosurgery and rhTNF-α. Tumor sizes were measured by magnetic resonance imaging; DNA fragmentation was detected by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL assay); P21(WAF1/CIP1) and proliferating cell nuclear antigen (PCNA) expression levels were scored using immunohistochemical staining. G2 and G4 rats had significantly longer survival time than did G1 rats. Tumor sizes in each group were significantly decreased as compared with those in G1 rats. PCNA-positive cells were significantly decreased in G2, G3 and G4 rats as compared with G1 rats. In contrast, DNA fragmentation and P21(WAF1/CIP1)-positive cells were significantly increased in each treatment group. Importantly, a combined treatment enhanced the effects of cryosurgery. Combined treatment with cryosurgery and rhTNF-α may have a synergistic effect on glioma tumor therapy, enhancing the inhibition of proliferation and the induction of apoptosis.     

Induction of specific-locus and dominant-lethal mutations by cyclophosphamide and combined cyclophosphamide-radiation treatment in male mice

Cyclophosphamide is the most widely used antineoplastic agent. It is also used to condition patients for bone-marrow transplantations. Because of the general interest of this compound we initiated a systematic study of the induction of dominant-lethal and specific-locus mutations in male mice. In addition, we investigated the induction of specific-locus mutations by the combined treatment of cyclophosphamide and ionizing radiation.A dose of 40 mg/kg bw of cyclophosphamide caused dominant-lethal mutations in male mice only in the 1st and 2nd week after treatment. A dose of 120 mg/kg induced dominant-lethal mutations in the mating intervals 1–21 days posttreatment. No dominant lethal mutations were observed after the 3rd week. The same differential spermatogenic response was observed for the induction of specific-locus mutations. Cyclophosphamide induced recessive mutations exclusively in spermatozoa and spermatids. No mutations were recovered from treated spermatocytes and spermatogonia. In contrast to cyclophosphamide, radiation induces specific-locus mutations in all germ-cell stages.The pretreatment with cyclophosphamide 24 h before radiation enhanced the frequency of specific-locus mutations in spermatogonia. The distribution of the observed mutations among the 7 loci and their viability supports the hypothesis that these mutations were induced by radiation rather than by cyclophosphamide. The compound causes an immediate inhibition of DNA and RNA synthesis in spermatogonia. The inhibition very likely interferes with the repair process. The disturbance of the repair process is probably the cause of the synergistic effect for the induction of specific-locus mutations in spermatogonia of mice after pretreatment with cyclophosphamide 24 h before irradiation.     

Pre-conditioning cryosurgery: cellular and molecular mechanisms and dynamics of TNF-α enhanced cryotherapy in an in vivo prostate cancer model system

Cryosurgery is increasingly being used to treat prostate cancer; however, a major limitation is local recurrence of disease within the previously frozen tissue. We have recently demonstrated that tumor necrosis factor alpha (TNF-α), given 4h prior to cryosurgery can yield complete destruction of prostate cancer within a cryosurgical iceball. The present work continues the investigation of the cellular and molecular mechanisms and dynamics of TNF-α enhancement on cryosurgery. In vivo prostate tumor (LNCaP Pro 5) was grown in a dorsal skin fold chamber (DSFC) on a male nude mouse. Intravital imaging, thermography, and post-sacrifice histology and immunohistochemistry were used to assess iceball location and the ensuing biological effects after cryosurgery with and without TNF-α pre-treatment. Destruction was specifically measured by vascular stasis and by the size of histologic zones of injury (i.e., inflammatory infiltrate and necrosis). TNF-α induced vascular pre-conditioning events that peaked at 4h and diminished over several days. Early events (4-24 h) include upregulation of inflammatory markers (nuclear factor-κB (NFκB) and vascular cell adhesion molecule-1 (VCAM)) and caspase activity in the tumor prior to cryosurgery. TNF-α pre-conditioning resulted in recruitment of an augmented inflammatory infiltrate at day 3 post treatment vs. cryosurgery alone. Finally, pre-conditioning yielded enhanced cryosurgical destruction up to the iceball edge at days 1 and 3 vs. cryosurgery alone. Thus, TNF-α pre-conditioning enhances cryosurgical lesions by vascular mechanisms that lead to tumor cell injury via promotion of inflammation and leukocyte (esp. neutrophil) recruitment.     

Immunological response of regional lymph nodes after tumor cryosurgery: experimental study in rats

Seven days after inoculation of metastasizing rat mammary tumor No. 1 into the thigh of 5-week-old female Sprague-Dawley rats, the tumor was treated cryosurgically by two-cycle freezing and by contact methods at -170 degrees C. Weights of the thymus and the spleen, histological findings of the lumbar lymph nodes, phytohemagglutinin (PHA)-induced blastogenesis of lymphocytes obtained from the lumbar lymph nodes and peripheral blood, and resistance rate to tumor rechallenge were examined 1, 3, 6, 10, and 17 week(s) after cryosurgery, with the following results: Thymus weight gradually decreased by 3 weeks after cryosurgery, while spleen weight increased by 1 week, recovering the preoperative level at 6 weeks. Paracortical hyperplasia of the lumbar lymph nodes markedly increased in 1 week and sinus histiocytosis increased after 3 weeks, both remaining at high values until 10 weeks, while germinal center hyperplasia showed a high value at 3 weeks and thereafter decreased gradually. PHA-induced blastogenesis of the lumbar lymph nodes significantly increased 1 week after cryosurgery and remained at its high value until 10 weeks. PHA-induced blastogenesis of peripheral lymphocytes showed the lowest value at 3 weeks and then significantly increased at 6 weeks. Resistance rate to rechallenge showed the lowest value at 3 weeks, reaching the highest level 10 weeks after cryosurgery. From the above results, it was suggested that anti-tumor immunity (resistance to tumor rechallenge) induced by cryosurgery was at the lowest level at 3 weeks after cryosurgery, and gradually increased starting at 6 weeks.(ABSTRACT TRUNCATED AT 250 WORDS)     

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。     

新加良附方对移植性小鼠肝癌抑制率及其凋亡影响研究

目的:观察新加良附方对移植性小鼠肝癌(H22)生长抑制作用及其对肿瘤组织中Bcl-2和Bax表达影响。方法:建立移植型H22动物模型,并将动物模型随机分模型对照、环磷酰胺(CTX)与新加良附方大、中、小剂量5组。新加良附大、中、小剂量组给药量分别为10g/kg、5g/kg和2.5g/kg;CTX组给药计量为17mg/kg;模型组给予等量无菌生理盐水。连续给药、给水12天处死模型小鼠分离肿瘤,检测肿瘤大小、称重计算肿瘤抑制率,并将肿瘤组织切片,免疫组化法检测Bcl-2和Bax基因。结果:新加良附大剂量组肿瘤抑制率为48.5%,与模型对照组比较,有统计学意义(P<0.01);新加良附大、中剂量可降低肿瘤组织中Bcl-2蛋白基因表达,升高Bax蛋白基因表达,与模型组比较,有显著性差异(P<0.01,P<0.05)。结论:新加良附方可抑制H22瘤体生长,且下调Bcl-2蛋白基因表达,上调Bax基因,提示新加良附方在抗肿瘤方面具有进一步深入研究价值。     

Responsiveness to humoral factors of mouse marrow colony forming cells after treatment with cyclophosphamide.

Humoral factors affecting granulopoiesis have been detected by culturing bone marrow cells in intraperitoneal diffusion chambers. This study investigated the possibility that treatment with drugs alters the ability of cells to respond to these factors. Three days after treatment with 200 mg kg-1 cyclophosphamide, donor marrow cells were more responsive than normal cells to the factors produced in cyclophosphamide pretreated hosts. The optimum timing of host pretreatment for maximum colony stimulation also differed for cells from cyclophosphamide treated and untreated donors and these effects were found to depend on the dose of drug given to the animals.     

RESPONSIVENESS TO HUMORAL FACTORS OF MOUSE MARROW COLONY FORMING CELLS AFTER TREATMENT WITH CYCLOPHOSPHAMIDE

Humoral factors affecting granulopoiesis have been detected by culturing bone marrow cells in intraperitoneal diffusion chambers. This study investigated the possibility that treatment with drugs alters the ability of cells to respond to these factors. Three days after treatment with 200 mg kg^-1 cyclophosphamide, donor marrow cells were more responsive than normal cells to the factors produced in cyclophosphamide pretreated hosts. The optimum timing of host pretreatment for maximum colony stimulation also differed for cells from cyclophosphamide treated and untreated donors and these effects were found to depend on the dose of drug given to the animals.     

Combined therapy with cyclophosphamide and DNA preparation inhibits the tumor growth in mice

Background

When cyclophosphamide and preparations of fragmented exogenous genomic double stranded DNA were administered in sequence, the regressive effect on the tumor was synergic: this combined treatment had a more pronounced effect than cyclophosphamide alone. Our further studies demonstrated that exogenous DNA stimulated the maturation and specific activities of dendritic cells. This suggests that cyclophosphamide, combined with DNA, leads to an immune response to the tumors that were grafted into the subjects post treatment.

Methods

Three-month old CBA/Lac mice were used in the experiments. The mice were injected with cyclosphamide (200 mkg per 1 kg body weight) and genomic DNA (of human, mouse or salmon sperm origin). The DNA was administered intraperitoneally or subcutaneously. After 23 to 60 days, one million tumor cells were intramuscularly grafted into the mice. In the final experiment, the mice were pre-immunized by subcutaneous injections of 20 million repeatedly thawed and frozen tumor cells. Changes in tumor growth were determined by multiplying the three perpendicular diameters (measured by caliper). Students' t-tests were used to determine the difference between tumor growth and average survival rate between the mouse groups and the controls.

Results

An analysis of varying treatments with cyclophosphamide and exogenous DNA, followed by tumor grafting, provided evidence that this combined treatment had an immunizing effect. This inhibitory effect in mice was analyzed in an experiment with the classical immunization of a tumor homogenate. The strongest inhibitory action on a transplanted graft was created through the following steps: cyclophosphamide at 200 mg/kg of body weight administered as a pretreatment; 6 mg fragmented exogenous DNA administered over the course of 3 days; tumor homogenate grafted 10 days following the final DNA injection.

Conclusion

Fragmented exogenous DNA injected with cyclophosphamide inhibits the growth of tumors that are grafted to mice after this combined treatment.     

Effect of nonspecific immune stimulation with BCG and polidin on the Ehrlich ascites tumor growth

Investigations were performed to study: 1) the antitumor effect of BCG pretreatment on the development of Ehrlich ascites tumor in mice; 2) the effect of BCG administration in relation to the period of time before tumor inoculation and the dose levels used, and 3) the antitumor effect of an associated pretreatment of BCG and Polidin on the development of Ehrlich ascites tumor. BCG administered prior to Ehrlich ascites tumor inoculation have a protective effect evidenced by a delay in tumor development, a prolonged survival of the tumor host and, in some cases, even inhibition of tumor growth. The effect of BCG was highly dependent on 1) the dose and the time of administration of BCG and) 2 the combined pretreatment of BCG and Polidin.     

Pre-conditioning cryosurgery: Cellular and molecular mechanisms and dynamics of TNF-α enhanced cryotherapy in an in vivo prostate cancer model system

Cryosurgery is increasingly being used to treat prostate cancer; however, a major limitation is local recurrence of disease within the previously frozen tissue. We have recently demonstrated that tumor necrosis factor alpha (TNF-α), given 4 h prior to cryosurgery can yield complete destruction of prostate cancer within a cryosurgical iceball. The present work continues the investigation of the cellular and molecular mechanisms and dynamics of TNF-α enhancement on cryosurgery. In vivo prostate tumor (LNCaP Pro 5) was grown in a dorsal skin fold chamber (DSFC) on a male nude mouse. Intravital imaging, thermography, and post-sacrifice histology and immunohistochemistry were used to assess iceball location and the ensuing biological effects after cryosurgery with and without TNF-α pre-treatment. Destruction was specifically measured by vascular stasis and by the size of histologic zones of injury (i.e., inflammatory infiltrate and necrosis). TNF-α induced vascular pre-conditioning events that peaked at 4 h and diminished over several days. Early events (4–24 h) include upregulation of inflammatory markers (nuclear factor-κB (NFκB) and vascular cell adhesion molecule-1 (VCAM)) and caspase activity in the tumor prior to cryosurgery. TNF-α pre-conditioning resulted in recruitment of an augmented inflammatory infiltrate at day 3 post treatment vs. cryosurgery alone. Finally, pre-conditioning yielded enhanced cryosurgical destruction up to the iceball edge at days 1 and 3 vs. cryosurgery alone. Thus, TNF-α pre-conditioning enhances cryosurgical lesions by vascular mechanisms that lead to tumor cell injury via promotion of inflammation and leukocyte (esp. neutrophil) recruitment.     

Experimental cryosurgery on bone: A light and electron microscopical investigation

Three rabbits were treated with cryosurgery on the lateral surface of the mandible. Osteocytes with normal appearance were not detected in the cortex after 2 or 7 days following cryosurgery. In the marrow cavity, cells appeared more resistant and often showed a normal morphology as studied with both light and electron microscopy. The reason why cells survived in the marrow cavity is probably due to a combination of sheltering bone and the near proximity to an intact circulation due to a patent alveolar artery.The uncertain extension of the cold front beyond the cortex may indicate that cryosurgery alone is not suitable if a tumor has invaded the marrow cavity, while more superficially located tumors can be eradicated. However, tumor invasion itself destroys the cortex and thus the marrow cavity will be more readily exposed to the more extensive cryosurgical techniques used in clinical cryosurgery.     

Cryosurgery of pulmonary metastases.

Indications and results of 33 cryosurgical interventions for metastatic tumors in the lung are presented. Regression of local and metastatic pulmonary growth on the contralateral side was observed in four cases. Nine cases showed temporary halt of metastatic pulmonary tumor growth. The technique of cryosurgery for pulmonary metastases is reviewed. The procedure of cryosurgery of pulmonary metastases was found to be an innocuous method to attempt both tumor destruction and eventually specific immunologic stimulation. Preliminary observations with the lymphocytes and sera indicate that cryosurgery of pulmonary metastases induces an increase in specific cell mediated immune response without producing blocking serum factors and may give rise to specific, complement dependent cytotoxic antibodies. In one case both mechanisms were observed after cryotherapy. In three cases with progressive disease, lymphocyte mediated cytotoxicity alone was stimulated.     

Investigation of the mechanism and the effect of cryoimmunology in the Copenhagen rat

This study examined the potential for "cryoimmunology" to increase the destruction of the Dunning AT-1 prostate tumor after cryosurgery. Two possible mechanisms explaining the cryoimmunologic response were studied. The first was that an antitumor antibody is produced after cryosurgery. The second was that freezing induces an immunostimulatory signal that creates a T-cell response to the tumor. Six groups of animals (three experimental groups and three control groups) were treated once per week for 4 weeks with different therapies designed to investigate these mechanisms. Three types of immune response were measured: (1) the anti-AT-1 tumor immune titer (Ab response) by serum ELISA, (2) the effect on secondary tumor growth after challenge with live AT-1 cells (size and weight of the secondary tumor over time), and (3) the nature of the immunologic infiltrate into the secondary tumors by immunoperoxidase stain. ELISA showed that immune titers were present in the experimental groups after therapy, but the presence of an immune titer did not have a significant effect on tumor propagation. Histology showed the immunologic infiltrate was similar in all groups. These results showed that an immune response to AT-1 tumor was measurable by serum antibody, but it did not significantly limit secondary tumor growth or affect tumor histology. This suggests that the growth of AT-1 tumors is not inhibited by a cryoimmunological response. Thus, the effect of in vivo cryosurgery in the AT-1 tumor system would likely be limited to cellular and vascular changes.