Induction of malignant transformation in vitro and mammary tumors in rats by two new potent anthracycline antitumor antibiotics,morpholinodaunomycin and cyanomorpholinoadriamycin

The two new potent anthracycline antitumor antibiotics, morpholinodaunomycin and cyanomorpholinoadriamycin, are nonmutagenic or weakly mutagenic in Salmonella typhimurium or V79 Chinese hamster cells, but highly active inducing DNA repair in in cultured rat hepatocytes. Both agents were found to induce malignant transformation in vitro of C3H M2 mouse fibroblasts and mammary tumors in female Sprague-Dawley rats. The data indicate a) that these new anthracyclines, too, are highly oncogenic and b) in conjunction with previously published results, that the predictive value of in vitro short-term tests for in vivo carcinogenicity is dependent on the employment of a battery of such tests.Abbreviations ADM adriamycin - CNMoADM cyanomorpholinoadriamycin - DNM daunomycin - MNNG N-methyl-N-nitro-N-nitrosoguanidine Dedicated to Dr. J.H. Weisburger on his 65th birthday     

Reactive oxygen-mediated damage to murine mammary tumor cells

We have shown, in a preliminary report, that macrophages can induce strand breaks in the DNA of co-cultured tumor cells (Chong et al., 1988). The present study is designed to determine if oxygen-centered species generated by the cell-free enzyme-substrate combination of hypoxanthine and xanthine oxidase can induce similar lesions and to identify the specific mediator(s). We report that co-incubation of murine mammary tumor cell lines with hypoxanthine and xanthine oxidase leads to the induction of DNA-strand breaks as determined by fluorescence analysis of DNA unwinding (FADU) assay or alkaline elution techniques. This damage is preventable by catalase which removes hydrogen peroxide but no protection is provided by agents to remove or prevent the formation of superoxide anion (superoxide dismutase), or hydroxyl radical (mannitol or the iron chelator o-phenanthroline). Likewise, cyclooxygenase or lipoxygenase inhibitors of arachidonate metabolism (indomethacin, nordihydroguaiaretic acid, caffeic acid) or bromophenacyl bromide do not alter the degree of DNA scission. Treatment with higher doses of oxygen species leads to significant toxicity as determined by evaluation of cell growth potential or colony-forming ability. Again, toxicity is prevented only by the presence of catalase. Tumor cells are able to rejoin strand breaks at lower, less toxic doses. When comparing different tumor cell subpopulations at various stages of progression, i.e., metastatic vs. nonmetastatic, for sensitivity to hydrogen peroxide-induced strand breakage, we found that at lower concentrations (less than 5μM) metastatic populations are sensitive whereas nonmetastatic populations exhibit no significant breakage. At higher concentrations of hydrogen peroxide, all lines were sensitive, suggesting that a lower threshold of sensitivity may exist for more progressed tumour cell lines.     

Immunotoxins up to the present day

Immunotoxins consist of monoclonal or polyclonal antibodies conjugated to bacterial or plant toxins. The toxins used are typically of the A-B type in which a toxic A chain is coupled to a B chain responsible for cell binding and facilitation of A chain entry into the cytosol. Two broad strategies have been followed: coupling intact toxins, or A chains alone, to antibodies. This review examines current progress inin vitro andin vivo research, including recent clinical studies, concentrating principally on ricin or ricin A chain conjugates. The future role of conjugates using membrane-acting toxins, immunolysins, is also discussed.     

Cell kinetic studies of endothelial cells in the adenocarcinoma EO 771 and the effect of cyclophosphamide

Cell kinetic studies of endothelial cells in the adenocarcinoma EO 771 growing in C57bl/6j mice and after transplantation into Balb/c-nu/nu mice, as well as of the effect of cyclophosphamide treatment have been carried out. The³H-thymidine labelling index of endothelial cells decreases from about 8% 3–6 days after tumour inoculation to about 3% at 18 days. This decrease parallels that of the labelling index of tumour cells, i.e. there is a positive correlation between the labelling index of endothelial cells and that of tumour cells. The labelling index of endothelial cells in the tumour periphery is two to three times as high as that in the tumour centre reflecting corresponding differences in the rate of proliferation. There is no difference in the proliferation of endothelial cells whether the tumour grows in C57bl/6j or in Balb/c-nu/nu mice. After treatment with cyclophosphamide the labelling index of endothelial cells decreases within 2 days to 1–2% and remains that low despite regrowth of the tumour with increased tumour cell proliferation, indicating that tumour relapse does not depend on tumour angiogenesis.     

Diagnosis of a peripheral neuroectodermal tumour by fine needle aspiration

One case of malignant peripheral neuroectodermal tumour successfully diagnosed by cytology is presented. Although a Papanicolaou stained smear could not lead to a diagnosis more specific than a malignant small cell tumour, ancillary analytic methods performed on the cytologic material including immunocytochemistry and electron microscopy yielded the correct diagnosis of peripheral neuroectodermal tumour. This case demonstrates that a precise categorization of small round cell tumours may be achieved by cytology as long as some material is kept for immunocytochemical and ultrastructural studies.     

A variation in the structure of the protein-coding region of the human p53 gene

An extensive analysis of genomic DNA preparations from a number of normal and malignant tissues revealed BglII site polymorphism of the human p53 gene. Approximately 10% of p53 gene alleles were found to contain an additional BglII site localized in a region of intron I. This allelic form of p53 gene was also responsible for p53 protein having altered electrophoretic mobility. Molecular cloning and sequencing of both the alleles of p53 gene revealed a base-pair change in codon 72 causing arginine → proline substitution in the allele with the additional BglII site. Both variants of the p53 gene may occur in homozygous state and are therefore functional.     

Serum copper,zinc levels,and copper

Serum copper and zinc levels were determined in 20 healthy women and in 100 women with gynecological tumors. Malignant and benign tumor cases were separated according to their postoperative, histopathological examinations. The stages of malignant and benign tumors were also established histologically. Seventy benign and 30 malignant genital tumors (carcinoma of cervix in situ, cervix, ovary endometrium, and vulva) of the patients were differentiated histopathologically. The serum Cu/Zn ratios of patients were increased significantly from the control group (0.32±0.35) to the benign group (1.22±0.63) and from the benign group to the malignant group (2.24±1.03). Nine of 30 malignant cases were determined as false negative (30%) and 15 of 70 benign cases were determined as false positive (14.2%) according to the serum Cu/Zn ratios of patients. Serum copper levels of 30 malignant and 10 benign tumor cases showed linear correlation with serum ceruloplasmin values.     

Effects of tumour necrosis factor-α (cachectin) on glucose metabolism in the rat

Intravenous administration of a single dose (20 g) of recombinant tumour necrosis factor- (TNF, cachectin) to rats decreased the rate of intestinal glucose absorption. In vivo, the oxidation of [U-¹⁴C]glucose to ¹⁴CO₂ was significantly increased by the cytokine. In addition, [¹⁴C]lipid accumulation from [U-¹⁴C]glucose was increased both in liver and brown adipose tissue of the TNF-injected animals. The decrease observed in intestinal glucose absorption was not associated with changes in intestinal metabolism. There was no difference in glucose metabolism by isolated enterocytes from either control or TNF-injected rats whether in the absence or presence of different concentrations of the cytokine in the incubation medium. In contrast, tumour necrosis factor altered the rate of gastric emptying as measured by the gastrointestinal distribution of [³H]inulin following an intragastric glucose load. These results suggest that the cytokine profoundly alters glucose metabolism by increasing its whole-body oxidation rate and delaying intestinal absorption through a reduced gastric emptying.     

Inhibition of rat yolk sac tumour growth in vivo by a monoclonal antibody to the retroviral molecule P15E

Summary A monoclonal mouse IgG2b antibody 19F8, directed towards a determinant on the retroviral transmembranous molecule p15E, binds selectively to certain rat tumours, including all tested yolk sac tumours, one rat colon carcinoma, one spontaneous kidney carcinoma and an adenovirus-type-9-induced rat breast tumour, as tested by antibody-dependent cellular cytotoxicity (ADCC) and immunohistochemistry. Groups of rats receiving yolk sac tumour F56 isografts intraperitoneally (i.p.) or subperitoneally (s.p.) were treated with this monoclonal antibody (mAb), 19F8, inoculated twice a week in doses of 100 µg. Parallel control groups received analogous inoculations of an isotype-matched monoclonal antibody. A significant growth inhibitory effect was observed with 19F8. In 5/10 rats isografted i.p., tumour outgrowth was completely inhibited and in the other 5 rats the outgrowth was delayed compared to the 10 rats in the control group, which all developed tumours. All rats of the control group developed large volumes of ascites, whereas the 5 rats in the therapy group with eventual tumour outgrowth had little or no ascites. In two experiments with rats carrying subperitoneal isografts and treated with the 19F8 mAb, tumour grew out in 4/5 and 5/10 rats, though growth was delayed compared to the control groups, in which 5/5 and 9/9 rats developed tumours. The tumours grew significantly more slowly in the therapy groups compared to the controls. All rats that developed tumours in the therapy groups showed an anti-idiotypic response against mAb 19F8. The single tumour-free rat in the first experiment and 1/5 tumour-free rats in the other showed no such response. The draining lymph node cells from the tumour-free animals showed a specific proliferative response to yolk sac tumour F56 cells in a mixed lymphocyte tumour cell culture (MLTC), and the MLTC-induced cells were cytotoxic to F56 but not to the natural-killer-sensitive rat T cell lymphoma G1—Tc1. The cytotoxic cell population was more than 90% CD4⁺. It is concluded that the two test systems for identification of the epitope of p15E detected by mAb 19F8 correlated well in detection of the epitope in the cells (immunohistochemistry) and at the cell surface (ADCC). It is also concluded that mAb 19F8 has a growth-inhibitory effect on yolk sac tumour F56 and that, as a result of the treatment, T cells with specificity for F56 are appearing in draining lymph nodes of tumour-free animals.     

Ecological aspects of a silicified bivalve fauna from the Silurian of Gotland

The silicified Wenlockian (Silurian) bivalve fauna from MÖllbos, Gotland, is part of a life assemblage. The vast number of shells show unusual phenomena, e.g. shell repair, pearl and tumour formation, etc. A number of shells contain epibionts and bored, round holes. Presumptive predators of the bivalve community are discussed. Size-frequency distribution of the two most abundant species possibly reflects age classes. The fauna, comprising eleven species, is dominated by deposit-feeders (90 %). They exhibit niche diversification, including at least three different feeding levels within the sediment.