Estrogen-like effects of tamoxifen on human endometrial carcinoma transplanted into nude mice

The effect of tamoxifen (TAM) on human endometrial carcinoma was investigated in nude mice bearing an estrogen receptor-positive or estrogen receptor-negative tumor. The receptor-negative tumor grew rapidly, and the rates of tumor growth of 17 beta-estradiol or TAM-treated animals were identical to the rate of controls. The estradiol receptor and progesterone receptor (PR) concentrations in the tumor cytosol remained undetectable under all experimental conditions. In contrast, the rate of growth of steroid receptor positive tumor was significantly accelerated in the presence of TAM compared to controls (p less than 0.02). The increased tumor growth rate was, however, significantly lower (p less than 0.01) than that observed in animals receiving 17 beta-estradiol. The PR concentration in these tumors was elevated in response to TAM treatment. That the TAM-induced PR was indeed functional was evident from (a) increased activities of the progestin-sensitive enzyme, 17 beta-estradiol hydroxysteroid dehydrogenase and (b) histological appearance of subnuclear vacuolization in these tumors after progestin administration. These studies indicate that continuous, short-term administration of TAM to nude mice results in an estrogen-like effect on endometrial carcinoma. Based on the finding that TAM induces functional PR, we predict that steroid receptor-positive endometrial carcinoma may show a greater response rate to combined, long-term treatment with TAM and progestin.     

Incorporation of alpha-1-antichymotrypsin into carcinoma cell nuclei of human stomach adenocarcinoma transplanted into nude mice

Human stomach adenocarcinomas containing alpha-1-antichymotrypsin (ACT) in their cell nuclei were transplanted into nude mice. The presence of ACT was monitored using an immunohistochemical technique with horseradish peroxidase-labeled rabbit anti-ACT Fab' as well as single radial immunodiffusion. Two weeks after transplantation, ACT could be found neither in transplanted carcinoma cells nor in the sera of carcinoma-bearing nude mice. However, if human ACT was injected i.v., it could be detected in the transplanted carcinoma cell nuclei 2 h after injection. The ACT was detected immunohistochemically and was confirmed by biochemical fractionation using 125I-labeled ACT. On the other hand, the amount of ACT production was not sufficient to indicate biosynthesis. These results demonstrated that ACT detected in stomach carcinoma cell nuclei was not synthesized in carcinoma cells but was incorporated from the blood circulation.     

Long-term observation on transplanted tumors of human intestinal mucoid adenocarcinoma in nude mice

Long-term observation on transplanted tumor of human intestinal mucoid adenocarcinoma in nude mice is reported. The transplanted tumor which has been passed 57 passages in 151 nude mice with transplant survival rate of 99.34% in more than 5 years is the tumor with the utmost number of passages domestically undertaken as yet. During the long-term observation, the transplanted tumor was not only identical to the primary tumor in histopathology, ultrastructure and chromosome pattern, but also constant in biological characteristics, such as secretion of mucin and production of carcinoembryonic antigen. These tumor cells were able to combine with CEA mcAb specifically by obviously showing the scanning image of transplanted tumor of human intestinal mucoid adenocarcinoma in nude mice with 131I-CEAmcAb. The roles of the transplanted tumor model in cancer research are discussed.     

Antitumor effect of human leukocyte interferon on human osteosarcoma transplanted into nude mice

We studied the effect of human leukocyte interferon (HuIFN-α) on a human osteosarcoma (OS-OH) transplanted and passed serially in athymic mice. The growth of OS-OH was strikingly inhibited by HuIFN-α (50,000 IU/mouse), regardless of whether the interferon treatment was initiated 24 hr after tumor inoculation or 2 weeks later, when tumors had grown to an appreciable size (4–6 mm). The antitumor effect of HuIFN-α was found to be dose-dependent and a daily administration of HuIFN-α(50,000 IU/mouse) all but completely arrested the tumor growth.     

Effects of dietary menhaden oil and retinyl acetate on the growth of DU 145 human prostatic adenocarcinoma cells transplanted into athymic nude mice

The effects of feeding menhaden oil (MO), rich in -3 fatty acids,or supplemental vitamin A [as retinyl acetate (RA)], on thegrowth of DU 145 human prostate cancer cells were studied inathymic nude mice. The mice were fed AIN-76A diets containingeither 23% corn oil (CO), a mixture of 17% MO and 6% CO, or23% CO plus RA. After irradiation sterilization, the RA-supplementeddiet was found to contain 15 times the amount of vitamin A presentin the control diet. There were 24 mice in each dietary group.Three weeks after commencement of feeding the experimental diets,1x10⁶ or 5x10⁶ DU 145 cells were inoculated into subgroups of12 animals, and the appearance and growth of solid tumors followedover a 6-week period. There was no significant difference intumor latency between mice fed MO plus CO, and those fed COalone, regardless of the inoculum size. However, the appearanceof palpable tumors was more rapid in mice inoculated with 5x10⁶cells and fed the RA-supplemented CO diet (91% after 17 days)compared with mice receiving the same tumor cell load but fedthe unsup-plemented CO diet (55% after 17 days). Growth of thesolid tumors was retarded significantly in mice inoculated with1x10⁶ cells and fed the MO-containing diet compared with theCO controls; this effect was not evident in animals who received5 10⁶ cells. RA supplementation caused accelerated tumor growth,which, again, only achieved statistical significance in thegroupinoculated with 1 10⁶ cells.     

血管内皮抑制素对Calu-6裸鼠移植瘤的生物学效应

目的 探讨血管内皮抑制素对Calu-6裸鼠移植瘤生长及新生血管形成的影响.方法 在荷瘤裸鼠皮下注射不同剂量的血管内皮抑制素,观察注射后肿瘤体积的变化;应用免疫组化SABC法检测肿瘤组织中血管内皮生长因子(VEGF)、生存素(survivin)和环氧化酶-2(COX-2)蛋白的表达以及微血管密度(MVD)的变化;流式细胞术检测循环血管内皮细胞(CECs)的含量;应用逆转录聚合酶链反应(RT-PCR)和实时定量PCR检测外周血中CD146和CD105 mRNA的表达.结果经血管内皮抑制素治疗后,荷瘤鼠肿瘤体积明显减小;肿瘤组织中VEGF、survivin和COX-2蛋白的表达以及MVD均下降,且各治疗组与阳性对照组间的差异均有统计学意义(均P＜0.05);外周血中CECs、CD146和CD105 mRNA的含量均明显下降;活化CECs的含量与肿瘤组织中survivin和VEGF的表达以及MVD的变化均呈正相关.结论 血管内皮抑制素可通过下调移植瘤中VEGF、survivin和COX.2蛋白的表达以及减少MVD抑制肿瘤生长;活化CECs将可能作为理想的预测抗血管形成治疗预后的标记物应用于临床.     

Chemosensitization with nitroimidazole to human gastric cancer transplanted into nude mice

Combined chemotherapy for human gastric cancer Transplanted into nude mice has been performed to determine whether misonidazole (MIS) and metronidazole (MTR), derivatives of nitroimidazole, would enhance the antitumor activity of MMC. MTR, 500 mg/kg, MIS 500 mg/kg, and MMC 2.0 mg/kg were administered ip twice during a 48-hour interval. The antitumor efficacies of MMC only, MTR only, or MIS only were seen to be much the same as in the controls. The combined treatment with MMC and MTR surpassed the controls in antitumoral activity after the 12th day, whereas it did not surpass a regimen with MMC alone. The addition of MIS to MMC showed an enhanced antitumoral activity after the 10th day compared to the controls and, further, after the 10th day it exceeded the results of MMC only. Tumor tripling time in cases of MMC only, MTR only, MIS only, MMC plus MTR, and MMC plus MIS was 123, 132, 144, 144, and 178 hours, respectively, compared to 110 hours in the controls. Thus, these results suggest that MIS has a chemosensitizing activity under these conditions, while MTR has little activity.     

Experimental combined hormone therapy on human breast carcinomas serially transplanted into nude mice

Experimental combined hormone therapy with tamoxifen, aminoglutethimide and medroxyprogesterone acetate was investigated using three hormone-dependent human breast carcinomas serially transplanted into nude mice. The antitumor effect of combined tamoxifen and aminoglutethimide was better than that of either tamoxifen or aminoglutethimide alone. Since aminoglutethimide significantly reduced the level of estrogen and the uterine weight in normal female mice, the antitumor effect of combined tamoxifen and aminoglutethimide was assumed to be a result of the low estrogen level produced by aminoglutethimide, favoring the competition of tamoxifen with estrogen receptors. There was no additive antitumor effect of the combination of tamoxifen and medroxyprogesterone acetate, although serum medroxyprogesterone acetate levels in nude mice were almost equivalent to those of humans. These results indicate that combination hormone therapy, especially with and aminoglutethimide, might be a promising method for clinical application.     

Gastric- and intestinal-type properties of human gastric cancers transplanted into nude mice

The gastric- and intestinal-type properties of 15 human gastric cancers, which were transplanted into nude mice, were studied biochemically and histologically. Enzyme activities were determined in the crude extracts of cancer tissues: pepsinogen isozymes as gastric marker enzymes; and sucrase, aminopeptidase (microsomal), and alkaline phosphatase as intestinal marker enzymes. By hematoxylin and eosin staining and paradoxical concanavalin A staining, gastric cancer tissues were classified into gastric type (pyloric gland cell type and surface mucous cell type) and intestinal type (goblet cell type and intestinal absorptive cell type). On the basis of their properties, human gastric cancers were classified into four types: (a) intestinal type; (b) gastric type; (c) intestinal plus gastric type; and (d) unclassified type, showing no gastric- or intestinal-type properties. Of six well-differentiated adenocarcinomas, four were of intestinal type, one of gastric type, and one of intestinal plus gastric type. All of the intestinal-type carcinomas showed sucrase activity. Of the three signet ring cell carcinomas, one was classified as a gastric type, one as an intestinal plus gastric type, and one as an unclassified type. Of the six poorly differentiated adenocarcinomas, five were of the intestinal type and one of the unclassified type. The present results clearly showed the appearance of intestinal-type properties in gastric cancer cells not only in so-called intestinal-type carcinomas, but also in diffuse-type carcinomas.     

Cell kinetics and chemosensitivity of human carcinomas serially transplanted into nude mice

Six human carcinoma xenografts serially transplanted into nude mice were used for the study of chemosensitivity and cell kinetics. Three gastric carcinomas (St-4, St-40 and H-111), two colon carcinomas (Co-3 and Co-4) and one breast carcinoma (MX-1) were inoculated into the subcutaneous tissue of BALB/cA nude mice. The maximum tolerable doses of mitomycin C (MMC), adriamycin (ADM), cyclophosphamide (CPA) and 5-fluorouracil (5-FU) were administered when the tumor weights reached 100-300 mg. The response rates of the tumor to these drugs were found to be 3/6 for MMC, 2/6 for 5-FU and 1/6 for ADM and CPA. Percent labeled mitosis curves obtained from 3H-thymidine pulse labeling were analyzed by the method of Quastler and Sherman. It was found that the antitumor effect of MMC was closely correlated with the growth fractions of the tumors (r = -0.98, P less than 0.001), and it appeared that the tumor cells were more sensitive to MMC in the resting stages during the proliferating phase than in the other cell cycle phases. Cell kinetics is considered to be an important factor in determining chemosensitivity, and the system of human tumor xenografts-nude mice seems to be a suitable experimental model for investigating the correlation between cell kinetics and chemosensitivity in vivo.     

Cell kinetics of human lung small cell carcinomas transplanted into nude mice

Three human lung small cell carcinoma (SCC) xenografts serially transplanted into BALB/c nude mice were used for cell kinetic analysis. SCC strains, Lu-24, Lu-130 and Lu-134, were inoculated into the backs of nude mice, and when each tumor reached more than 300 mg, 50 microCi of 3H-thymidine per mouse was administered ip. The percentage labeled mitosis curve was obtained from the autoradiographic specimens which were labeled by the pulse-chase method. Cell cycle phase, growth fraction (GF) and cell loss factor (CL) were assessed by the methods of Quastler, Fujita and Steel, respectively. These cell kinetic parameters were compared with those of six control human gastrocolic and breast carcinoma xenografts which were previously reported by us. It was noticed that the cell cycle times (Tc) of SCC were statistically shorter than those of controls and this short Tc was found to be dependent on their short post-mitotic resting phases. GFs and labeling indices of SCC were observed to be statistically lower than those of controls, suggesting an incomplete adaptation of SCC xenografts to the host nude mice. Whereas some modifications by the host mice on the cell kinetics were supposed, the characteristics of SCC cell kinetics were thought to be essentially preserved in nude mice and these kinetic parameters were observed to be stable throughout the serial transfers. Accordingly, the SCC xenograft-nude mouse system was considered to be useful as an experimental therapeutic model of human lung small cell carcinomas.     

四硫化四砷对裸鼠卵巢癌皮下移植瘤生长的影响

目的 利用BALB／C裸鼠和人卵巢癌细胞株SKOV3建立裸鼠皮下移植瘤,探讨四硫化四砷在卵巢癌组织中的抑瘤作用及机制。方法 建立卵巢癌SKOV3裸鼠皮下移植瘤模型,按照给药剂量（50mg／kg和100mg／kg）及肿瘤生成大小（3mm×3mm和10mm×10mm）将裸鼠随机分成小剂量早期治疗组、大剂量早期治疗组、小剂量治疗组和大剂量治疗组,分别予四硫化四砷隔日灌胃,并设裸鼠生理盐水对照组。观察四硫化四砷对肿瘤的生长的影响;RT-PCR法及Western blotting法检测四硫化四砷对肿瘤组织中Bcl-2／Bax蛋白和mRNA表达的影响。结果 各组裸鼠一般情况良好。小剂量早期治疗组、大剂量早期治疗组和大剂量治疗组的抑瘤率分别为84.98％、87. 55％和74.25％,与小剂量治疗组的35.19%相比,差异均有统计学意义（P＜0.05）。RT-PCR显示肿瘤组织Bcl-2 mRNA表达下调和Bax mRNA表达上调,Western blotting显示其Bcl-2蛋白表达降低和Bax蛋白表达增加。结论 四硫化四砷可以抑制卵巢癌裸鼠皮下移植瘤的生长,并诱导卵巢癌细胞凋亡。其作用机制可能与凋亡调控基因Bcl-2／Bax表达的改变有关。     

Glucocorticoid-induced growth inhibition with enhanced expression of ductal epithelium of human salivary gland adenocarcinoma cells transplanted into athymic nude mice

The effect of glucocorticoid on growth and the histologic features of adenocarcinoma induced in nude mouse by the inoculation of neoplastic epithelial cells of salivary duct origin (HSG) were studied. Subcutaneous injection of dexamethasone (low-dose group: 0.05 micrograms/g, high-dose group: 0.25 micrograms/g) four times a week for 8 weeks significantly (P less than 0.05) inhibited tumor growth, and in one mouse the tumor had almost completely disappeared by the middle of the sixth week of treatment. In addition, dexamethasone induced an apparent luminal structure in the tissue section of the tumor and enhanced the immunoperoxidase reaction to epithelial membrane antigen. The results indicate that dexamethasone inhibited the proliferation of HSG cells in the nude mouse transplantation system probably by inducing the cellular differentiation of the HSG cells toward the more differentiated ductal epithelia via glucocorticoid receptors.     

Synergistic effect of recombinant human interferon-beta and -gamma on human colon cancer transplanted into nude mice

The antitumor effect of recombinant human interferon-beta (r IFN-beta) and recombinant interferon-gamma (r IFN-gamma) was studied in vivo using a pulmonary metastatic model involving nude mouse human colon cancer xenografts. The results indicated that both r IFN-beta and r IFN-gamma had an inhibitory effect on pulmonary metastases. Furthermore, a combination of r IFN-beta and r IFN-gamma acted synergistically in the inhibition of pulmonary metastases. These results suggested that a combination of r IFN-beta and -gamma could be a most effective form of interferon therapy for cancer.     

Estrogen- and androgen-responsive growth of human ovarian adenocarcinoma heterotransplanted into nude mice

A new line of human serous cystadenocarcinoma of the ovary, designated OVA-5, has been established in athymic nude mice. A strong correlation was noted between tumor volume and plasma CA125 levels in mice bearing OVA-5 tumor. Growth of the OVA-5 tumor in castrated male nude mice was accelerated by s.c. administration of estradiol-17 beta and 5 alpha-dihydrotestosterone but not by progesterone. Estradiol-17 beta and 5 alpha-dihydrotestosterone also accelerated the growth of the OVA-5 tumor heterotransplanted into sialoadenectomized castrated male nude mice. No remarkable change was observed in the histological appearances of the tumors between control groups and hormone-treated groups. Receptor assays revealed that the OVA-5 tumor had both estrogen and androgen receptors. Growth of the OVA-5-tumor is thus responsive to estrogen and androgen.