An inverse relationship between the growth rate of human melanoma xenografts and their response to some cytostatic drugs.
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Animals↗
Biomedical subjects
O Fodstad
Publications and source records attributed to O Fodstad.
Assessment of tumour growth and of response to chemotherapy of human melanomas in athymic, nude mice.
The growth of 6 different human melanomas xenografted into athymic mice was followed by measuring 2 vertical diameters twice weekly. The growth rate of the xenografts was expressed as the tumour doubling time, measured in the volume range 30-60 mm3. None of the xenografts increased their growth rate with increasing number of passages. The tumour lines, which were histologically very similar, showed individual, characteristic growth rates differing by a factor of 3. Evidence was obtained that resistance to cytostatic drugs in the patients is retained in the xenograft. Procedures for evaluating response to chemotherapy are discussed.
Animals↗
Synergistic effect of adriamycin and ricin on L1210 leukemic cells in mice.
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Animals↗
Human embryonal carcinoma grown in athymic mice and in vitro.
Tissue from 19 human testis tumors was transplanted into athymic mice. One embryonal carcinoma, ECCS, grew rapidly, and this tumor was studied both as a xenograft and an in vitro culture of xenograft-derived tumor cells. Xenografts showed no evidence of differentiation. The embryonal carcinoma cells were heteroploid and showed alkaline phosphatase activity. When tumor cells from the xenografts were grown in vitro, the cells formed aggregates resembling embryoid bodies with epithelium-like cells in the periphery. Regularly, another population of mouse cells which showed several criteria of malignancy overgrew the culture and could be subcultured continuously. These abnormal cells may result from an in vivo or in vitro transformation of mouse stromal cells.
Alkaline Phosphatase↗
Doxorubicin and ricin, a strongly synergistic combination in mouse leukemia.
The effect of combinations of doxorubicin (Adriamycin) and the cancerostatic plant lectin ricin on L1210 leukemic cells in mice was assessed by end-point dilution and spleen-colony assays. The combinations, which were well-tolerated by the mice, acted synergistically on leukemic cells in liver, spleen, and brain. In the bone marrow, a dramatically synergistic effect was obtained with combinations that had only slight effect on the survival of normal stem cells.
Animals↗
Treatment of micrometastases from Lewis lung carcinoma with abrin and cyclophosphamide, given singly and in combination.
The effect of the plant toxin abrin and of cyclophosphamide given as adjuvant chemotherapy after irradiation of the primary tumor was studied in mice bearing intramuscularly growing Lewis lung carcinoma. The chemotherapy was given immediately after irradiation performed 9 days after inoculation of 10(5) tumor cells. The drugs were given in bolus injections either as single agents or concurrently. The therapeutic effect was assessed by recording the appearance of lung metastases on day 21 or the number of long-term survivors, i.e. animals alive at day 60. In the control group 21 +/- 3.4 (SD) macroscopic lung colonies was recorded on day 21. Mean survival time was 25.5 days with none of the mice alive at day 60. The optimal abrin dose (612.5 ng/kg IV) reduced the number of lung metastases to 2.6 +/- 0.8 and yielded 37% long-term survivors (11/30). The optimal dose of cyclophosphamide (150 mg/kg IP) reduced the number of lung colonies to less than 1 and yielded 61% survivors (14/23). Small to moderate doses of abrin significantly potentiated the therapeutic effect of cyclophosphamide without increasing the toxicity. The best results (18/20 or 90% long-term survivors) were obtained when the optimal dose of cyclophosphamide, 150 mg/kg, was combined with 350 ng/kg of abrin. The results obtained in this highly resistant tumor suggest that combinations of the two drugs may be useful also in other tumor types.
Abrin↗
Toxicity of abrin and ricin in mice and dogs.
Mice and dogs, were treated iv with the cytostatic proteins abrin and ricin and observed for clinical, biochemical, and morphological aberrations. In both mice and dogs death occurred within a narrow dose range. Dogs given toxic doses of ricin and abrin showed weakness, anorexia, apathy, and moderate fever. No signs attributable to the central nervous system were observed. Dogs dying from intoxication expired after 15-40 h. After nonlethal doses the animals recovered, apparently completely, in 1-3 wk. No delayed changed were observed in dogs after 4 mo. Abrin and ricin, in contrast to most other cytostatic agents, did not inhibit myelopolesis. However, after sublethal dpses a rapid but translent decrease of peripheral thrombocytes was observed. No evidence for specific liver damage or impairment of kidney function was obtained. Few abnormalities were observed at autopsy or on microscopic and electron microscopic examination of the tissues, in contrast to the findings of some earlier investigators. The results indicate that in mice and dogs given sublethal doses of highly purified toxins the symptoms are reversible. There was no finding militating against a phase 1 clinical trial.
Abrin↗
Human gastrointestinal cancer grown in nude mice used to test new chemotherapeutic agents.
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Abrin↗
Effect of ricin and abrin on survival of L1210 leukemic mice and on leukemic and normal bone-marrow cells.
The effect of ricin and abrin on the survival of mice treated with L1210 leukemic cells intraperitoneally or intravenously was studied. In mice given 1 X 10(5) L1210 leukemia cells intraperitoneally a single dose of ricin (2.1 microgram/kg) intraperitoneally gave the best results, an increased life span (ILS) of 59%. Abrin also increased the life span of such animals although to a lesser extent. The effect of ricin was superior to that of 5-fluorouracil, but inferior to that of adriamycin, which gave a maximum ILS of 280%. In mice given L1210 cells intravenously no increase in life span was obtained with ricin, abrin or adiramycin, whereas 5-fluorouracil gave an ILS of 40-50%. In spleen colony assays the differential effect of ricin and abrin on the proliferative capacity of normal hematopoietic and leukemic colony-forming cells in bone marrow was studied. The differential effect of ricin was as good as that of adriamycin and considerably better than that of 5-fluorouracil. Abrin had a much smaller effect than ricin on both normal and leukemic cells. The effect of abrin on the leukemic cells was too small to be of therapeutic value. The results warrant exploration of the use of ricin in the treatment of human leukemia.
Abrin↗
Studies on the accessability of ribosomes to inactivation by the toxic lectins abrin and ricin.
The rate of protein synthesis in HeLa cells was measured at various periods of time after addition of abrin and ricin to the medium and compared with the concurrent ability of the isolated ribosomes to support poly(U)-stimulated synthesis of polyphenylalanine in a cell-free system. Similarly, the endogenous synthesis in unfractionated cell-free systems from HeLa cells and rabbit reticulocytes was compared with the ability of the isolated ribosomes to support poly(U)-stimulated polymerization of phenylalanine. In the intact cells and the unfractionated cell-free systems protein synthesis decreased progressively with the time after addition of toxins or toxin A chains. In contrast, the ability of the isolated ribosomes to support polyphenylalanine synthesis was only moderately reduced initially and then remained constant or even increased. The activity of isolated monosomes decreased progressively with time after addition of toxin A chain, whereas polysomes were only partly inactivated and the extent of inactivation varied from one experiment to another. The results indicate that the inactivation of one or a few ribosomes per polysome stops the translation of mRNA. It is suggested that the intact ribosomes thus trapped are inaccessible to the toxins and that the isolation of polysomes results in release of functionally intact ribosomes capable of supporting poly(U)-directed polymerization of phenylalanine.
Abrin↗
Inhibitory effect of abrin and ricin on the growth of transplantable murine tumors and of abrin on human cancers in nude mice.
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Abrin↗
Toxicity, distribution and elimination of the cancerostatic lectins abrin and ricin after parenteral injection into mice.
The survival time of mice after i.v. injection of the cancerostatic lectins, abrin and ricin was recorded. The LD50 dose was found to be 10-13 ng and 55-65 ng per mouse for abrin and ricin, respectively. Increasing amounts of toxin reduced the survival time, reaching a minimum of about 10 h. Lactose injected with ricin, provided partial protection against ricin, as measured by the survival time. Abrin and ricin labelled with 125I, and shown to retain their full toxic activity, were injected into mice. Most of the radioactivity found in the organs was present in the form of intact toxins, at least up to 5 h after injection. After i.v. injection the highest concentration/g tissue was found in spleen, followed by kidneys, heart, liver and thymus. The relative concentration in liver was considerably higher for ricin than for abrin. Similar results were found after i.p. injection. When lactose was administered together with ricin, almost 80% of the ricin injected was found in the liver after 30 min, compared to 48% without lactose, and the amount in other organs was concurrently reduced. The elimination of total radioactivity was much faster for ricin than abrin. The radioactivity found in the urine was largely present in non-trichloroacetic acid precipitable form, indicating that the toxins were extensively degraded before excretion.
Abrin↗
Athymic rats in preclinical immunodiagnostic studies.
The usefulness of nude rat xenograft systems in immunolocalization studies was investigated using the monoclonal antibody 9.2.27 which binds to melanomas and osteosarcomas. Three human tumors, two melanomas (LOX and FEMX-I) and one osteosarcoma (OHSX), were used. They were established as s.c. xenografts in congenitally athymic (rnu/rnu) nude rats. These serially transplantable tumors showed the same morphology, take rate and growth properties in nude rats as in nude mice. Radiolabeled 9.2.27 F(ab')2 fragments injected i.v. into nude rats were concentrated in s.c. LOX and OHSX xenografts, reaching tumor to blood ratios of up to 30 after 3-4 days. However, the injected antibody failed to concentrate in FEMX-I xenografts, in contrast to previous findings in mice. This discrepancy could be attributed neither to significant differences in in vivo distribution of the labeled antibody nor to the presence of blocking factors in the serum of nude rats. In immunoscintigraphic studies clear images of s.c. LOX tumors were obtained, whereas lung colonies were less well visualized. Biodistribution studies showed a low tumor to blood ratio of about 4 in the latter animals, suggesting a tumor site-dependent variation in homing of labeled antibodies. Radiography was found to be superior to immunoscintigraphy in detecting the lung tumors. The present findings demonstrate that results of immunolocalization studies in nude mice cannot readily be extrapolated to other species. For the purpose of preclinical evaluation of new methods in cancer diagnosis and treatment, tumor xenografts in nude rats may represent a valuable complement to nude mouse models.
Animals↗
Methodological aspects of the 6-day subrenal capsule assay for measuring the response of human tumors to anticancer agents.
Methodological aspects of testing chemosensitivity by the 6-day subrenal capsule (SRC) assay in immunocompetent mice were investigated. Human tumor xenografts, serially transplanted in athymic nude mice, were used as source of material. All drugs were given by the intravenous route. Administration of the drugs on days 1 and 2 gave the same results as when they were given daily for 5 days in equitoxic total doses, and a clear dose-response relationship was demonstrated. High reproducibility was found with different anti-cancer agents when 15 different tumors (4 melanomas, 7 soft tissue sarcomas, 2 colon carcinomas, and 2 lung carcinomas) were tested repeatedly over a period of several years. The tumors examined showed individual chemosensitivity profiles. The same ranking of drugs was found when the results in the SRC assay were compared with those obtained in the sc nude mouse model, using the same tumors (a colon carcinoma and a leiomyosarcoma), supporting the validity of the SRC assay. Altogether, the results strongly support the view that the 6-day SRC assay in immunocompetent mice is a useful method for assessing the response of human tumors to anticancer agents.
Animals↗
Expression and release of plasminogen activators, their inhibitors and receptor by human tumor cell lines.
Plasminogen activators (PAs) and their inhibitors (PAIs) can be produced by tumor cells and surrounding inflammatory cells and fibroblasts. The present study evaluate both the expression and release of PAs (uPA and tPA) and PAIs (PAI-1 and PAI-2) from cultured cells, and also the expression of uPA receptor (uPAR). Immunocytochemistry showed that PAs, PAIs and uPAR were present to different extents on the surface of colon carcinoma cells (Caco-2, HT-29), malignant melanoma cells (LOX) and normal fibroblasts. uPA immunoreactivity was intermediate in Caco-2, HT-29 and LOX and weak in the fibroblasts. tPA immunoreactivity was intermediate in Caco-2 and LOX and weak in HT-29 and fibroblasts. PAI-1 and PAI-2 immunoreactivities were absent in HT-29, weak in Caco-2 and strong in fibroblasts. In LOX the immunoreactivity was intermediate for PAI-1 and strong for PAI-2. uPAR immunoreactivity was weak in Caco-2, HT-29 and LOX and negative in fibroblasts. ELISAs on conditioned medium detected that the colon carcinoma cells Caco-2 and HT-29 did not release any PAs or PAIs. LOX released tPA (median 9 ng/million cells at 72 hours), PAI-1 (1050 ng/million cells) and PAI-2 (245 ng/million cells), and fibroblasts released uPA (1 ng/million cells) and PAI-1 (910 ng/million cells). These results show that both tumor cells and fibroblasts express tissue destructive enzymes, PAs and PAIs, whereas only the tumor cells express the uPAR required for focalization and regulation of PA activity at the cell surface. The melanoma cells LOX and fibroblasts also released PAs and PAIs, in contrast to the colon carcinoma cells Caco-2 and HT-29.
Cell Line↗
Cysteine proteinase inhibitors reduce malignant melanoma cell invasion in vitro.
Proteolytic enzymes are believed to be necessary for tumor cell invasion. We have studied the effects of the cysteine proteinase inhibitor E-64 and the serine and cysteine proteinase inhibitor leupeptin, on the ability of human malignant melanoma cells (LOX) to pass through an artificial basement membrane. Transwell chambers containing filters coated with the reconstituted basement membrane, Matrigel, were used. Nontoxic concentrations of the proteinase inhibitors reduced the invasion of LOX cells through Matrigel. E-64 (250 mumol/l) by 27% and leupepetin (250 micrograms/ml) by 46%. The proteinase inhibitors did not alter the growth rate of the tumor cells, their motility through uncoated filters, or their attachment to the Matrigel coated wells. Our results indicate that cysteine proteinases are involved in the degradation of basement membranes and thus contribute to the invasion of malignant melanoma cells.
Animals↗
Interleukin-1 alpha and basic fibroblast growth factor induction of matrix metalloproteinases and their inhibitors in osteosarcoma cells is modulated by the metastasis associated protein CAPL.
BACKGROUND: Several recent investigations have shown that the expression of the CAPL protein seems to be of importance in the metastatic potential in some types of cancer. However, the mechanisms behind this and other biological functions of CAPL are still largely unknown. The aim of the present work was to investigate whether CAPL could affect the expression of candidate proteolytic facilitators of the metastatic process, i.e. matrix metalloproteinases (MMPs) and their inhibitors (TIMPs). MATERIALS AND METHODS: A highly metastatic osteosarcoma cell-line with a high expression of CAPL was transfected with either a vector containing a ribozyme against this transcript, or with the vector alone as a control. The expression of MMPs and TIMPs was investigated with ELISA and gelatin zymography. RESULTS: The cell-line with a low CAPL expression (III-14) responded to bFGF treatment by an increased synthesis of MMP-1 and MMP-9 and to Il-1 alpha treatment by an increased synthesis of MMP-9. In contrast, the cell-line with a high CAPL expression (pH beta-1) did not respond with an altered expression of these MMPs. Neither of these two cell-lines responded with an altered expression of MMP-2. bFGF treatment resulted in an increased expression of TIMP-1 in both cell-lines, while Il-1 alpha treatment resulted in a decreased production of TIMP-1 in pH beta-1 cells, and III-14 cells were unaffected. CONCLUSIONS: The CAPL protein expressed in cell-cultures appear to block the MMP induction by bFGF and Il-1 alpha. However, the induction of TIMP-1 by bFGF must proceed through a pathway different from the MMP induced pathway, i.e. a pathway unaffected by CAPL. In addition, CAPL appeared to act in synergy with Il-1 alpha to reduce the synthesis of TIMP-1.
Bone Neoplasms↗