Human neuroblastoma serially transplanted in nude mice and metastases

Animal models of extracranial pediatric solid tumors

Animal models, including xenografts, models of metastatic invasion, syngeneic models and transgenic models, are important tools for basic research in solid pediatric tumors, while humanized animal models are useful for novel immunotherapeutical approaches. Optical and molecular imaging techniques are used for in vivo imaging and may be used in conjunction with alternative treatment approaches, including photodynamic therapy. The aim of this review is to highlight the various animal models that may be used for basic research in pediatric solid tumors.

Distinct morphological and immunohistochemical features and different growth rates among four human neuroblastomas heterotransplanted into nude mice

To elucidate more precisely the biological characteristics of neuroblastomas, we examined four human neuroblastomas heterotransplanted into athymic nude mice NB-39 (undifferentiated type), NB-45 (poorly differentiated type with undifferentiated component), NB-52 (poorly differentiated type), and NB-726 (differentiating type) by electron microscopy, immunohistochemistry, and radioimmunoassay for the peptides in tumors. Ultrastructurally, NB-45, NB-52, and NB-726 contained more numerous and variously sized neurosecretory granules than did NB-39. Immunohistochemistry revealed neurofilament proteins, tyrosine hydroxylase, neuropeptide Y (NPY), and chromogranin A-positive cells in the four tumors in the following order of frequency: NB-726, NB-45, NB-52, and NB-39. NB-726, NB-45, and NB-52, but not NB-39, contained galanin-positive tumor cells. NB-45 and NB-726 harbored a few positive cells for calcitonin gene-related peptide. Furthermore, NB-726 exhibited positivity to leu-enkephalin, met-enkephalin, vasoactive intestinal peptide (VIP), and serotonin. Radioimmunoassay substantiated the results of immunohistochemistry, showing NPY in all tumors and either galanin or VIP in three tumors, excepting NB-39. Average doubling time of the tumor was as follows: 2 days in NB-39, 10 days in NB-45, 22 days in NB-52, and 45 days in NB-726. These results indicate that human neuroblastoma cells have different biological characteristics and reduced growth rate with differentiation in terms of ultrastructure and of peptide production abilities.

Tumorigenicity, invasion, and metastasis of human gastric cancer in nude mice

Tumors derived from 105 patients with gastric cancer were subcutaneously heterotransplanted into nude mice in order to study their tumorigenicity and malignant behavior. Of the 105 gastric cancers, 45 were successfully transplanted (a 42.9% tumorigenesis rate). The tumorigenesis rate of Borrmann type 1 and 2 cancers (77.8%) was significantly higher than that of type 3 and 4 cancers (34.6%). Also, the tumorigenesis rate of differentiated carcinoma (57.1%) was significantly higher than that of undifferentiated carcinoma (30.9%). Spontaneous metastases from the subcutaneous tumors were observed in 5 of the 37 established tumor lines (13.5%), and macroscopic pulmonary metastases were common with one tumor line (SCK-29). Although most of the subcutaneous gastric cancers showed local expansion without distant metastasis, the same tumor cells implanted into the peritoneal cavity exhibited invasive growth and/or metastasis. Thus, the expression of a metastatic phenotype by human gastric cancer was influenced by the host microenvironment. The SCK-29 tumor line with its high metastatic potential may be useful for studies on the mechanism of blood-borne metastasis.

Mesenchymal differentiation of cell lines obtained from human gliomas inoculated into nude mice

Tumor formation in nude mice (nu/nu Balb c outbred) inoculated with cells from four new permanent human glioma cell lines was studied. Three of these lines had previously been shown to display features of striated muscle in vitro. Histochemical and immunochemical techniques together with electron microscopic study confirmed that striated muscle differentiation continued to be expressed in vivo. Two of the cell lines arguably showed greater striated muscle differentiation in vivo, whereas one has lost this ability. In one of the two, further mesodermal differentiation was evident with the formation of cartilage.

Growth and metastasis of human tumors in nude mice following tumor-cell inoculation into a vascularized polyurethane sponge matrix

Growth and metastasis of human tumor cells in immunodeficient nude mice were improved when tumor cells were inoculated within a vascularized artificial polyurethane sponge matrix. The sponges had been implanted 7-10 days earlier and were vascularized at the time of cell injection. All cell lines tested, including colon carcinoma-derived lines from primary tumors (HT29, PT3 and PT4) or from liver metastasis (LM3), and a metastatic variant from a melanoma (MeWo-Met) grew in a high percentage (78-94%) of the inoculated sponge grafts. When growth in sponge grafts is compared with growth at a subcutaneous site, the sponge matrix appears to increase tumorigenicity, at least for some cell lines. Regular formation of metastases was observed when cells had been injected into sponges. Most metastases were found in a second sponge graft implanted at a contralateral site, but some were also found at other s.c. sites. In vivo depletion of NK cells by pre-treatment with cyclophosphamide could not further enhance the formation of metastasis. Tumor cells from fresh surgical specimens could be propagated in sponge matrix grafts and subsequently established as cell lines in tissue culture.

Invasion and metastasis of SY86B human gastric carcinoma cells in nude mice

A moderately differentiated tubular adenocarcinoma of human stomach, named SY86B, was successfully transplanted subcutaneously to nude mice of different genetic backgrounds (BALB/CA/PBI-nu, C57BL/6J.615/PBI-nu and ICR.BALB/CA/PBI-nu). The tumor has been passaged for 13 generations and the transplantability was 100%. The SY86B cells retained the capacity of invasive and metastatic growth in the nude mice and showed a high rate of metastasis to the regional lymph nodes and to such distant organs as the lungs, liver and pancreas. The overall rate of metastasis was 77.7%. The species of the nude mice, their age and sex apparently did not significantly affect the occurrence of metastasis. Tumor-bearing time and the aggressive character of the tumor cells themselves appeared important for the genesis of metastasis. This experimental model can provide a new approach to basic and clinical studies of cancer metastasis.

Novel experimental models of human cancer metastasis in nude mice: lung metastasis, intraabdominal carcinomatosis with ascites, and liver metastasis

The ability of RPMI 4788 cells, a human colon cancer cell line, to produce experimental metastases in the lung, intraperitoneal cavity, and liver was studied in nude mice. Injection of 2 X 10(6) tumor cells into the tail vein of nude mice produced metastatic lung tumors, and an intraportal injection of 5 X 10(6) cells produced metastatic liver tumors. An intraabdominal carcinomatosis with ascites was formed after an i.p. injection of 5 X 10(6) tumor cells. The nude mice with lung metastasis or intraabdominal carcinomatosis always died within a few weeks. Macroscopic observation showed that the number of lung metastatic nodules on day 21 after tumor inoculation was 311.3 +/- 78.2 (mean +/- SD) in BALB/C nude mice, and 187.5 +/- 26.7 in ICR nude mice. In survival experiments, the mice with intraabdominal carcinomatosis showed a mean survival of 29.0 +/- 1.7 (mean +/- SD) days in BALB/C nude mice and 43.6 +/- 6.1 days in ICR nude mice. These novel experimental models of metastases in nude mice produced by injection of RPMI4788 cells had high reproducibility and may be useful not only for the study of the metastatic process but also for testing anticancer drugs.

Metastatic neuroblastoma arising in an ovarian teratoma with long-term survival. Case report and review of the literature

A case of neuroblastoma arising in an immature teratoma of the ovary in a 22-year-old woman is reported. Differentiation was grade 3 in the primary and metastases. Metastases to retroperitoneal, mediastinal, and supraclavicular lymph nodes and to bone were diagnosed 2 years after presentation of the primary tumor. Electron microscopic study demonstrated dense-core granules of the neurosecretory elements. Treatment with combination chemotherapy followed by radiotherapy resulted in complete remission which continues to the time of this report, more than 4 years after diagnosis of the primary tumor. Prolonged survival of metastasizing grade 3 immature teratoma is distinctly uncommon. The literature pertaining to this unusual tumor and to neuroblastoma of adults is reviewed.

Morphology and function of human neuroblastoma xenotransplanted in nude mice

Nine human neuroblastomas were serially transplanted in nude mice. All transplanted tumors were taken from patients older than the age of 1 year 10 months. In contrast, the authors were unable to transplant tumors from patients younger than 1 year 7 months of age, in spite of many attempts. All transplanted tumors produced varying amounts of cathecolamines as revealed by the liquid chromatography and formalin-induced fluorescence techniques. The content of the cathecolamines was closely correlated with the number and size of secretory granules. In high cathecolamine-producing tumors, cell clusters showing strong yellow-orange fluorescence plus a positive argyrophil reaction suggesting pheochromoblastic differentiation were demonstrated by our combined cathecolamine fluorescence and argyrophil reaction method. One of the transplantable tumor lines was demonstrated by unique host responses and biochemical data, to produce adrenocorticotropic hormone and increased cathecolamines. Our observations indicate that neuroblastoma derived from neural crest cells seem to have a nearly complete hormone production function as compared with their normal counterparts.

Plasminogen activator activity of metastatic variants from a murine fibrosarcoma; effect of thrombin in vitro

In order to investigate the possible correlation between plasminogen activator (PA) activity and metastatic potential of tumour cells, we studied cultured cells from the murine fibrosarcoma mFS6 and from its two sublines M4 and M9 which differ markedly in their capacity to cause spontaneous metastases in the lung. PA activity was detected in all the sublines by an amidolytic method and was almost completely inhibited by treatment with antiurokinase antiserum. No significant differences were shown between mFS6, M4 and M9. Moreover, molecular analysis of PA by SDS-PAGE electrophoresis and fibrin overlay revealed in all the cell types a single species having a mol. wt. of approximately 48,000 daltons. Thrombin treatment dramatically inhibited the amidolytic activity of all cells, suggesting a role for this enzyme in the modulation of fibrin formation and dissolution within the primary neoplasm.

Metastasis of a human pancreatic adenocarcinoma (RWP-1) in nude mice

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Establishment of an experimental model of human hepatoblastoma

Establishment of xenografts or cell culture lines in which the alpha-fetoprotein (AFP) characteristic of clinical hepatoblastoma persists have been difficult. The serially transplantable strain (HB-3) of highly AFP-producing hepatoblastoma was successfully established in nude mice. And a highly AFP producing cell line (c-HB-3) is easily obtained by HB-3. This strain and line give us an ideal experimental model of hepatoblastoma in vivo and in vitro.

Heterotransplantation of small-cell carcinoma of the lung into nude mice: comparison of intracranial and subcutaneous routes

We compared and contrasted intracranial (i.c.) and subcutaneous (s.c.) heterotransplantation of small-cell carcinoma of the lung (SCCL) into athymic nude mice. Fresh human SCCL tumor specimens, tumor colonies grown in soft agarose and continuous cell lines were used. Tumors induced by the three types of specimens were similar, but s.c. and i.c. transplants differed. S.c. tumors had longer latent times, were non-invasive and non-lethal. I.c. tumors has shorter latent periods, invariably grew in the meninges, frequently invaded and destroyed the underlying brain, and were lethal. The tumor-inducing dose for i.c. transplantation was 10 to 1,000 times lower than for s.c. transplantation. Pooled colonies of SCCL tumor specimens grown in soft agarose were inoculated i.c. While they contained relatively small numbers of cells (400-10,000), 83% of these colony specimens induced tumors after 58-243 days, confirming the "stem-cell" origin of the colonies. I.c. and s.c. transplants retained the characteristic morphology of SCCL, and, with one exception, did not metastasize to distant organs. Continuous cell lines could be established readily from both types of transplants, and they retained the characteristic cytology, growth and biochemical properties of the original SCCL tumors. I.c. heterotransplantation of SCCL is a useful tool, especially when small numbers of tumor cells are available, and may provide a model to study the biology and therapy of meningeal carcinomatosis.

A transplantable human malignant Schwannoma

A human malignant Schwannoma was serially transplanted through three generations in nude mice. The tumours grew readily and the take-up rate was 100 per cent. No metastasis was observed in nude mice. Morphological features of the original tumour were strictly maintained through all the transplant generations. The tumour cells of the original and of the transplants showed features of primitive Schwann cells of embryonic nerve trunks.