Chemotherapy of human alpha-fetoprotein-producing gastric carcinomas grown in nude mice

We have examined the effects of chemotherapeutic drugs on tumor growth and metastasis of human alpha-fetoprotein-producing gastric carcinoma (AFPGC) xenografts growing in nude mice. These xenografts consisted of 3 hepatoid adenocarcinomas and 2 non-hepatoid, poorly differentiated adenocarcinomas. Mitomycin C and cisplatin inhibited the tumor growth and liver metastasis of hepatoid adenocarcinomas in nude mice. 5-fluorouracil also inhibited the growth of hepatoid adenocarcinomas but did not exhibit a significant antimetastatic action. Doxorubicin was effective only against non-hepatoid adenocarcinomas. These results indicate that chemotherapeutic drugs for AFPGC should be used according to the subtype of the tumor.     

Growth kinetics of four human breast carcinomas grown in nude mice

Summary The immune-deficient nude mouse with human tumor xenografts is an appropriate model system for performing detailed growth kinetic examinations. In the present study one estrogen and progesterone receptor-negative (T60) and three receptor-positive (Br-10, MCF-7, T61) human breast cancer xenografts in nude mice were investigated. The proliferative tumor characteristics were examined by growth curves, thymidine labelling technique, and flow cytometric DNA analysis performed on fine-needle aspirations. The results showed that the tumors had growth kinetics comparable to other human tumor types with cell generation times of 42 to 60 hours. The three receptor-positive tumors had slower growth rate, larger tumor volume doubling time, and smaller growth fraction and labelling index than the receptor-negative tumor. However, no single proliferation parameter was sufficient to characterize the growth kinetics of individual tumors or to describe proliferative differences between the tumors.     

Intrinsic and acquired multidrug resistance in human lung carcinomas grown in nude mice

Human epidermoid lung carcinoma xenografts with intrinsic and induced resistance were analyzed with regarding to different parameters. The xenografts with intrinsic resistance to vincristine (HXL 54) and induced drug-resistance sublines to vincristine (HXL 55/VCR), actinomycin D (HXL 55/AD) and cisplatin (HXL 55/DDP) were characterized in terms of the degree of resistance, cross-resistance, proliferation kinetics, tumorigenicity, keratin and P-glycoprotein expression. The results demonstrate that xenografts with intrinsic or induced resistance to vincristine or actinomycin D exhibit a similar general pattern of cross-resistance to that observed in multidrug-resistant cell lines. The resistance cannot be attributed to differences in proliferation kinetics. Development of resistance is associated with loss of tumorigenicity and features of differentiation, P-glycoprotein is little expressed in the resistant xenograft lines and corresponds well with the low grade of resistance.     

Cyclooxygenase inhibitors decrease the growth and induce regression of human esophageal adenocarcinoma xenografts in nude mice

Cyclooxygenase (COX) inhibition has been shown to prevent the development of esophageal adenocarcinoma (EAC). However, the potential of this approach for treatment of established cancer has been poorly investigated. Our objective was to determine whether non-selective or selective inhibition of the COX pathway affects the growth of esophageal adenocarcinoma xenografts in nude mice. A human esophageal adenocarcinoma xenograft model was established by subcutaneous inoculation of OE33 cells in nude mice. Small tumor slices harvested from four OE33 xenografts were implanted in the flanks of new mice that were randomized to different treatments (6 animals per group): indomethacin (3 mg/kg/day), parecoxib (0.11 and 0.22 mg/kg/day) or a selective prostaglandin E? receptor antagonist (AH-23848B, 1 mg/kg/day). For each treatment, a control group of 6 animals (vehicle) carrying xenografts from the same OE33 tumor was included. Tumor growth was measured twice a week. After 8 weeks mice were euthanized. Tumors were assessed by histological analysis, mRNA expression of COX isoenzymes, PGE? receptors and PGE? content. All OE33 tumors were poorly differentiated esophageal adenocarcinomas. Tumors expressed COX-2, EP?, EP? and EP? receptor mRNA. Treatment with parecoxib, higher dose or indomethacin significantly inhibited tumor growth. Furthermore, indomethacin induced tumor regression (74 vs 582% in control animals; p<0.01). However, AH-23848B or parecoxib low dose failed to affect tumor growth significantly. PGE? content in tumors was significantly decreased by high-dose parecoxib and indomethacin. Indomethacin and parecoxib inhibit the growth of human esophageal adenocarcinoma xenografts in nude mice, which suggests a potential role for NSAIDs or selective COX-2 inhibitors for EAC chemotherapy.     

Growth of human bronchial carcinomas in nude mice

Two hundred and thirteen lung tumours of primary site and 42 metastases were heterotransplanted into nude mice with an overall success rate of 44%. There were differences in success between the histological types. Squamous cell and adenocarcinoma had the highest success rate (51% and 43%, respectively) whereas large cell and small cell carcinoma had a lower success rate (38% for both). The average volume doubling times in the first passage in nude mice ranged from 8.2 in large cell carcinomas to 18.9 days in adenocarcinomas. In subsequent passages an increase in growth rate was found, the overall average doubling time falling from 14.5 days in the first passage to 7.1 days in the second passage. In a study with 171 non-small cell lung carcinomas (NSCLC), the growth data in nude mice were correlated with the clinical data of the corresponding patients. A relationship between the growth parameters in nude mice and prognosis of patients could not be found.     

The effects of alpha and gamma interferons on human lung cancer cells grown in vitro or as xenografts in nude mice

We have compared the effects of alpha and recombinant gamma interferons (IFNs) on the growth of human lung cancer cell lines in vitro. There was a diversity of response amongst the lines studied, the most sensitive being COR-L23 (a large cell anaplastic carcinoma line) and POC (a small cell line). In these two lines, IFN-gamma was found to be more potent than IFN-alpha. During cell growth of line POC in the presence of IFN-gamma no significant shift in cell cycle distribution occurred. When lines COR-L23 and POC were grown as xenograft tumours in nude mice, daily injection of 4 X 10(5) units per mouse per day of IFN-gamma produced no discernible retardation of tumour growth.     

Endocrine therapy of human breast cancer grown in nude mice

Although there have been extensive studies of rodent breast tumor models, and of human breast cancer cell lines in culture, there is still need for a human tumor model which can be manipulated experimentally but also provides a valid expression of the tumor cells in a host environment. Athymic nude mice bearing transplanted human breast tumors have been proposed as such a model. This review therefore discusses the use of the athymic nude mouse model of the study of human breast cancer biology, and focuses on four subjects: 1. biological characteristics of heterotransplanted breast tumors; 2. endocrinology and pharmacology of hormonal agents in the nude mouse; 3. endocrine sensitivity of heterotransplanted tumors; and 4. applicability and limitations of this model for the study of human breast cancer.     

Transformation of immortal, non-tumorigenic osteoblast-like human osteosarcoma cells to the tumorigenic phenotype by nickel sulfate

Epidemiological studies have indirectly linked compounds ofchromium, nickel and arsenic to human carcinogenesis. However,there is no evidence that metal compounds can transform humancells to the tumorigenic phenotype in culture. We show herethat exposure to 36 µM NiS0₄ for 48–96 h resultsin transformation of an immortal, non-tumorigenic, osteoblast-likecell line, HOS TE85, to the tumorigenic phenotype. Continuouspassaging following treatment leads to the formation of a fewdense foci. The cells isolated and expanded from the foci aremorphologically transformed, and form anchorage-independentcolonies of the size and abundance comparable to that formedby Kirsten murine sarcoma virus transformed HOS TE85 cells.The transformed cells from tumors in nude mice, have enhancedlevels of plasminogen activators and have lost the ability toform model bone matrix on extended culture in the presence ofascorbic acid and ß-glycerophosphate. A number ofcell lines have been established from nude mouse tumors. Cytogeneticanalysis reveals 16 marker chromosomes and an aberrant chromosome16. This is the first report of the transformation of a humancell line to tumorigenic phenotype by a metal carcinogen.     

Membrane-type 1 matrix metalloproteinase-mediated progelatinase A activation in non-tumorigenic and tumorigenic human keratinocytes

Elevated expression of type IV collagenases (MMP-2 and MMP-9) has been strongly correlated with tumour progression and metastasis in various tumours. Here, we analysed expression and activation of these MMPs in non-tumourigenic HaCaT cells and the malignant HaCaT variant II-4(rt). In monolayer cultures, both cell types secreted latent MMP-2 (proMMP-2) in comparable amounts, while MMP-9 production was clearly higher in II-4(rt)cells. Upon contact with fibrillar collagen type I the malignant II-4(rt)cells, but not the HaCaT cells, gained the capability to activate proMMP-2. This process is shown to be membrane-associated and mediated by MT1-MMP. Surprisingly, all membrane preparations from either HaCaT cells or II-4(rt)cells grown as monolayers, as well as within collagen gels, contained considerable amounts of active MT1-MMP. However, within collagen gels HaCaT cells showed significantly higher TIMP-2 levels compared to II-4(rt)cells. This indicates that TIMP-2 might play a central role for MT1-MMP-mediated gelatinolytic activity. Indeed, collagen type I-induced MT1-MMP-mediated proMMP-2 activation by II-4(rt)membranes could be completely abolished by an excess of TIMP-2. In conclusion, our data suggest that MT1-MMP-mediated proMMP-2 activation might be associated with malignant progression of epidermal tumour cells.     

Antitumor effect of monoclonal antibody-carboplatin conjugates in nude mice bearing human ovarian cancer cells

Background. The antitumor effect and toxicity of immunoconjugates were studied in nude mice bearing a human ovarian cancer cell line, OVA-1. Methods. We studied the tissue distribution of an anti-cytokeratin-8 monoclonal antibody (6D7) in OVA-1-bearing nude mice by giving 6D7 labelled with ¹²⁵I. The immuno conjugate consisted of 6D7 and carboplatin (6D7-conjugate), coupled via carboxymethyl dextran, and this was intraperitoneally administered to OVA-1 bearing nude mice. The tumor volume and the body weight were measured for 5 weeks. Tissue platinum concentrations in the OVA-1 tumor, blood, liver, kidney, and spleen, were measured from 3 to 120 min after administration of the conjugate. The results were compared with those in nude mice treated with nonspecific mouse IgG coupled with carboplatin (IgG-conjugate) or carboplatin alone. Results. The coupling rate of the drug to 6D7 was approximately 80%, and was stable over several measurements at various times. In-vivo accumulation of 6D7 labelled with ¹²⁵I in the OVA-1 tumors was significantly higher than that in mice that received nonspecific mouse- IgG-¹²⁵I, with tumor/ blood radioactivity ratios of 14.0 and 1.28, respectively. The tumor growth rate in mice that were administered 6D7-conjugate was (at a maximum) 40% lower than the tumor growth rate in mice administered carboplatin. The body weight of the mice that received 6D7-conjugate did not decrease during the 5-week observation period, while the body weight of the mice that received carboplatin decreased by a maximum of 10%. In addition, upon administration of 6D7-conjugate, the platinum concentration in the tumor was maintained for a longer period than after the administration of carboplatin alone. Conclusions. The tumor growth suppression effect was significantly higher in the mice bearing the OVA-1 tumor that received 6D7-conjugate than in the animals that received carboplatin alone. This difference could be caused by differences in the platinum concentrations in the tumor between the two groups. Received: November 9, 1998 / Accepted: March 23, 1999     

The free cytoplasmic calcium concentration of tumorigenic and non-tumorigenic human somatic cell hybrids

The fluorescent indicator of Ca2+ concentration, quin-2, has been used to measure the concentration of free Ca2+ in the cytoplasm of tumorigenic and non-tumorigenic human somatic cell hybrids. The cell hybrids were derived from the fusion of a HeLa derivative (D98 AH2) and normal human fibroblasts. The calcium concentration of the tumorigenic cell lines was 180 +/- 7nM and the level in the non-tumorigenic cells was 136 +/- 6nM. This difference was statistically highly significant (P less than 0.001). Control experiments are reported which show that the level of 3a2+ measured is not influenced by cell density or by the concentration of quin-2-tetra-(acetoxymethyl)ester used in these experiments. The possible implications of this elevated level of cytoplasmic calcium in tumorigenic cells are discussed.     

Dynamic contrast-enhanced magnetic resonance imaging rapidly indicates vessel regression in human squamous cell carcinomas grown in nude mice caused by VEGF receptor 2 blockade with DC101

The purpose of our study was the investigation of early changes in tumor vascularization during antiangiogenic therapy with the vascular endothelial growth factor (VEGF) receptor 2 antibody (DC101) using dynamic contrast-enhanced magnetic resonance imaging (DCE MRI). Subcutaneous heterotransplants of human skin squamous cell carcinomas in nude mice were treated with DC101. Animals were examined before and repeatedly during 2 weeks of antiangiogenic treatment using Gd-DTPA-enhanced dynamic T1-weighted MRI. With a two-compartment model, dynamic data were parameterized in "amplitude" (increase of signal intensity relative to precontrast value) and k(ep) (exchange rate constant). Data obtained by MRI were validated by parallel examinations of histological sections immunostained for blood vessels (CD31). Already 2 days after the first DC101 application, a decrease of tumor vascularization was observed, which preceded a reduction of tumor volume. The difference between treated tumors and controls became prominent after 4 days, when amplitudes of treated tumors were decreased by 61% (P =.02). In line with change of microvessel density, the decrease in amplitudes was most pronounced in tumor centers. On day 7, the mean tumor volumes of treated (153 +/- 843 mm(3)) and control animals (596 +/- 384 mm(3)) were significantly different (P =.03). After 14 days, treated tumors showed further growth reduction (83 +/- 93 mm(3)), whereas untreated tumors (1208 +/- 822 mm(3)) continued to increase (P =.02). Our data underline the efficacy of DC101 as antiangiogenic treatment in human squamous cell carcinoma xenografts in nude mice and indicate DCE MRI as a valuable tool for early detection of treatment effects before changes in tumor volume become apparent.     

Morphological, biological, and biochemical characteristics of human bladder transitional cell carcinomas grown in tissue culture and in nude mice

The morphological, biological, biochemical, and karyotypic characteristics of four human bladder transitional cell carcinoma lines, SW-780, SW-800, SW-1738, and SW-1710, were investigated. In tissue culture, each cell line presented a distinct phenotypic expression. All but line SW-1710 grew when transplanted in the nude mouse. Light and electron microscopic studies showed morphological characteristics similar to the tumors of origin, being independent of the passages in tissue culture medium, tumor cell extracts, and the plasma of nude mouse-grown tumors, showing isoenzyme quantitative distribution typical for each cell line. In addition, each cell line exhibited a unique genetically determined enzyme phenotypic profile which, along with the karyotypic analysis, makes their identification feasible. These characteristics make the described tumor lines a valuable tool in studying various aspects of the biology of human bladder transitional cell carcinoma.     

Inhibition of human ovarian cancer cell growth in vitro and in nude mice by prostaglandin D2

In vitro and in vivo effects of prostaglandin D2 on human ovarian tumor growth were examined by using a cell line, designated HR, derived from ascites of a patient with serous cystadenocarcinoma of the ovary. The HR cell proliferation in vitro was dose dependently inhibited between concentrations of 0.1 and 4.0 micrograms of prostaglandin D2 per ml. From results of 51Cr release assays and trypan blue dye exclusion tests the inhibitory effect seemed to result from a direct cytotoxic effect by prostaglandin D2. All DNA, RNA, and protein syntheses by the HR cells were also inhibited in a dose-dependent manner with exposure time of 48 h to prostaglandin D2. When 5 X 10(5) HR cells were inoculated to nude mice, the 50% survival time of them in untreated groups was 52 days after inoculation. Although 4 mg of prostaglandin D2 per kg caused inhibition of the tumor growth, a significant prolongation of the survival time was not observed. On the other hand, the 50% survival time of nude mice treated with 12 mg of prostaglandin D2 per kg was significantly (P less than 0.05) prolonged to 67 days, in addition to a significant inhibition of the tumor growth.     

Intraperitoneal xenografts of human epithelial ovarian cancer in nude mice

Using continuous human ovarian cancer cell lines, i.p. xenografts were successfully established in nude mice from four of four attempts. When primary tumor material was used, xenografts grew in 8 of 10 attempts. From these eight, three passageable xenograft cell lines have been established. To our knowledge, this is the first report published of such xenografts. I.p. xenografts closely mimic the clinical behavior of human ovarian cancer, and those developed from primary tumor material maintain close morphological similarity to the parent primary tumor. When expression of placental alkaline phosphatase and the tumor associated antigens defined by the monoclonal antibodies HMFG1, HMFG2, AUA1, and F36/22 by these models was determined, those i.p. xenografts derived from primary tumor material exactly matched the original tumor, while none of the xenografts derived from the cell lines expressed these antigens. These models will be useful for investigating the biology and treatment of ovarian cancer.     

Blood coagulation changes in nude mice bearing human colon carcinomas.

We studied several blood coagulation parameters and tumor tissue procoagulant activity (PCA) in nude mice bearing human colorectal carcinomas (HCC). In a control group of 51 tumor-free nude mice, platelet number was 1.2 +/- 0.03 x 10(6)/microliters, thrombotest activity 90% +/- 2.6 and fibrinogen 172 +/- 11 mg/dl. The same parameters were studied in nude mice (n = 71) bearing 7 different HCC lines subcutaneously (s.c.). The results did not significantly differ from those in control mice but there was broad variability among groups of mice injected with different HCC lines, ranging from 0.36 to 2.55 x 10(6)/microliters for platelets, from 100 to 28% for thrombotest activity and from 42 to 460 mg/dl for fibrinogen. The results were significantly (p less than 0.05) different from those in the tumor-free group when each group of HCC-bearing animals was analyzed individually. A malignant HCC line that grew in the liver of nude mice (n = 24) significantly (p less than 0.001) reduced thrombotest activity (58% +/- 5.9). The PCA of tissue extracts from tumors grown s.c. in nude mice was assayed. All the HCC xenografts expressed PCA which differed significantly for the various tumor lines (from 25.5 +/- 1.9 to 2.8 +/- 0.6 unit/mg in tumor tissue). Cancer procoagulant (CP), a cysteine proteinase with a direct factor-X-activating effect, was present in different amounts (84.7 +/- 4.3 to 59.5 +/- 9.0%) in the tumors. Our results indicates that the nude mouse is a suitable model for evaluating the hemostatic changes induced by human tumors and may represent a tool for investigating the underlying biochemical mechanisms.     

Evaluation of new anticancer agents against human pancreatic carcinomas in nude mice

Heterotransplantation of human cancers in nude mice has provided an in vivo model for studying the biologic characteristics of human tumors, particularly their response to chemotherapy. In an effort to identify cytotoxic agents effective against pancreatic carcinoma, this model was used to evaluate the efficacy of three new anticancer agents--menogarol, 4'-epirubicin, and taxol--against two human transplanted pancreatic tumors. Relative area (tumor length X width) differed significantly between menogarol-treated and control groups (p = 0.034). A marked response was also observed in the tumors to 4'-epirubicin (p = 0.01). Taxol was ineffective in controlling tumor growth; by the fourth week, the size of treated tumors was similar to that of the control group (p = 0.55). No toxicity was observed in either the menogarol- or taxol-treated animals. Animals bearing the P2 tumor, and treated with 4' epirubicin displayed severe toxicity by day 18 with death by day 21 in most animals. For the second tumor, Capan-1, relative area differed significantly between the menogarol-treated and the control group (p = 0.003). In animals given 4'-epirubicin, a smaller difference was observed when comparing the relative areas (p = 0.09). Animals treated with taxol again showed no difference in the tumors when compared with controls (p = 1.0). The use of the nude mouse system has evolved so that tumor-oriented trials are now feasible with the hope of clinical applicability. This study illustrates that at least two agents--menogarol and 4'-epirubicin--may have some antitumor activity against pancreatic carcinoma in this system.