In two separate experiments, 2.0mg of 3-amino-1-methyl-5H-pyrido [4, 3-b] indole (Trp-P-2) was applied to the back of female CD-1 mice twice weekly for 5 weeks followed by application of 2.5μg of 12-O-tetradecanoylphorbol-13-acetate (TPA) twice weekly for 47 weeks. Skin squamous cell papillomas and carcinomas developed in 6 of 20 mice (30%) in Experiment 1 and in 3 of 19 mice (16%) in Experiment 2. In contrast, application of 2.0mg of Trp-P-2 twice weekly for 52 weeks did not produce any skin tumors. These data suggest that Trp-P-2 acts primarily as an initiator, not as a complete carcinogen, for mouse skin.

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Infectivity was assayed by infecting human T-lymphocytes, H9, Molt-4, and MT-4 cells with different strains of AIDS viruses (HTLV-III, LAV, ARV, and YU viruses). Human T-lymphotropic virus type-III (HTLV-III), lymphadenopathy-associated virus (LAV), and AIDS-associated retrovirus (ARV) were able to infect all kinds of target cells tested and to induce virus-specific antigens, whereas Japanese isolates, YU viruses, infected only interleukin-2-dependent human T-lymphocytes. Long-term propagation of the YU viruses and pretreatment of the cells with Polybrene did not allow the YU virus to produce viral antigens by infecting H9, Molt-4, and MT-4 cells. Thus, YU viruses have a rather narrow host range as compared with HTLV-III, LAV, and ARV. These different infectivities may be reflected in the progress and symptoms of AIDS in vivo.

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c-Ha-ras oncogene product in human gastric carcinomas was examined by Western blotting and immunohistochemistry using anti-Ha-ras p21 antibody. In Western blotting, high levels of c-Ha-ras p21s were found in gastric carcinomas. Immunohistochemically, c-Ha-ras p21 was detected in 3 (11.1%) of 27 early carcinomas and in 63 (43.8%) of 144 advanced carcinomas. In advanced carcinomas, c-Ha-ras p21-immunoreactivity was correlated with the depth of tumor invasion and was stronger in metastatic tumors than in primary tumors. Patients with c-Ha-ras p21-positive carcinomas had a significantly worse prognosis than those with p21-negative carcinomas.

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Seventeen liposoluble bis (carboxylato)-cyclohexane-1, 2-diammineplatinum (II) and bis (carboxylato)-cis-diammineplatinum(II) complexes were synthesized and tested for antitumor activity against leukemia L1210 cells in mice. The former complexes had excellent antitumor activity without any toxicity to the host at the therapeutic dose when used with lipiodol as a carrier solvent. The latter complexes had neither antitumor activity nor toxicity in vivo. The former complexes were gradually released from lipiodol to saline in vitro; the latter were not. The activity depended on the chain length of the carboxylato residue and also on the molecular shape of the ligand part of the complexes.

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The topical application of quercetin, an anti-tumor promoter, to mouse skin reduced the number of phorbol ester receptors, although quercetin did not inhibit specific ³H-12-O-tetradecanoylphorbol-13-acetate binding to a mouse skin particulate fraction. Quercetin, morin, kaempferol and luteolin inhibited activation of protein kinase C by teleocidin, and caused half-maximal activation at 25μM. (+)-Catechin, which has been reported not to inhibit tumor-promoting activity, did not have any effect on these reactions. The modulation of phorbol ester receptors and inhibition of activation of protein kinase C are considered to be involved in the anti-tumor-promoting effect of quercetin in mouse skin. Diet containing 4% or 1% quercetin did not influence the action of teleocidin on mouse skin in a two-stage carcinogenesis experiment.

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At 22hr after ip injection into adult male Wistar rats, 1, 1, 2-trichloroethane was covalently bound to DNA, RNA and proteins of the liver, kidney, lung and stomach, as has been found with various weakly carcinogenic halo compounds. The extent of interaction of 1, 1, 2-trichloroethane with mouse liver DNA was much higher than that with rat liver DNA. This result provides evidence of a correlation between adducts formation and species susceptibility to hepatocarcinogenesis (only the mouse is sensitive to the oncogenic effect of this compound). Interaction with DNA mediated by murine liver microsomes occurred in vitro. No particular differences between the two species were found. In vitro binding was enhanced (-5-fold) by pretreatment in vivo with phenobarbitone but was suppressed by addition of 2-diethylamino-ethyl-2, 2-diphenylvalerate•HCl in vitro. Cytochrome P-450 was, therefore, involved in the interaction process. Glutathione suppressed the microsome-mediated interaction, acting as a “scavenger” of reactive intermediate (s). Murine lung microsomes were less effective bioactivators than liver microsomes for the interaction with DNA and microsomal RNA, but not microsomal protein. Kidney and stomach microsomes were ineffective, as were cytosolic fractions from all of the assayed organs of the two species. The extent of in vitro interaction of 1, 1, 2-trichloroethane with synthetic polyribonucleotides was of the same order of magnitude as that with DNA. The results represent further clear evidence for genotoxicity of 1, 1, 2-trichloroethane.

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High levels of c-myc mRNA were observed in two human tumor cell lines, a giant cell carcinoma of the lung (C-Lu99) and a colon cancer (C1). The increased expression of c-myc in these cell lines, which was comparable with those in cell lines in which the c-myc gene is amplified, was not due to gene amplification. Run-on transcription revealed that the transcriptional rate of the c-myc gene was greatly increased in these cell lines.

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When proteins in the tissue extracts of lung cancers were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (PAGE), a 37, 000-dalton protein (37K) was detected as a prominent form in all cases thus far examined. This protein was barely detectable or its amount was very small in the normal lung tissue extracts. Two-dimensional PAGE of lung tumor extracts showed 37K as a major spot with an isoelectric point of 7.6. An antibody against 37K was raised in a rabbit by injecting purified 37K. Immunoblot analysis of normal lung and lung tumor tissues revealed that the affinity-purified anti-37K antibody specifically recognized 37K and that the intensities of immunostaining corresponded to those of Coomassie brilliant blue staining.

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Human lung cancers of all histological types contain a protein of 37, 000 daltons (37K) as an abundant component. Partial sequence analysis of purified 37K revealed a strong homology with glyceraldehyde-3-phosphate dehydrogenase (GAPDH, EC 1.2.1.12). Tryptic peptide mapping analysis showed that the pattern of 37K was very similar to those of GAPDHs both purified from lung tumor and obtained commercially. An antibody raised against 37K in a rabbit also reacted with authentic GAPDH. These results suggest a possible involvement of GAPDH itself or a GAPDH-related protein in lung tumorigenesis.

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Activity of transforming growth factor (TGF) in urine was examined by the use of cloned BALB/3T3 A31-1-1 indicator cells. When urine was extracted by an acid-ethanol method, fractionated on a Bio-Gel P-100 column, and analyzed for TGF activity, samples from healthy persons showed no activity, but 80% of the samples from advanced cancer patients had the activity. Activity observed in tumor-bearing patients was eliminated after therapy. Further analysis was carried out in a much simpler way by the fractionation of urine samples after only dialysis and lyophilization. An extensive survey of TGF activity in urine using BALB/3T3 indicator cells revealed weak or intermediate (19%) activity in healthy persons and high (56%) or intermediate (31%) activity in advanced cancer patients. When urine samples were analyzed and compared using both BALB/3T3 cells and NRK 49F cells, the BALB/3T3 cells were shown to form colonies in response to β-type TGF but not to α-type TGF. The present results are the first demonstration of an elevated level of β-type TGF in urine from cancer patients.

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The effect of nude gene heterozygosity on spontaneous AKR thymic lymphoma-genesis was studied by comparing female littermates of AKR/Ms-nu/+and+/+. As previously reported in nude gene heterozygotes with genetic background other than AKR, AKR/Ms-nu/+ mice had a significantly smaller thymus than the +/+ littermates. Overall incidences of thymic lymphomas were comparable in the two genotypes, but the mean latent period for lymphoma development was significantly shorter in the nu/+mice (266.3±11.6 days) than in the +/+ mice (319.3±7.9 days). Both genotypes of mice expressed a high level of XC⁺-ecotropic murine leukemia virus. Expression of xenotropic virus was more variable, but there was no consistent difference in onset of virus expression or in virus titer that could explain accelerated lymphomagenesis in the nude gene heterozygotes.

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The role of the thymus in propylnitrosourea (PNU)-induced thymic lymphomagenesis was studied in F344 rats with genetically determined high susceptibility. The thymus was absolutely required for thymic lymphomagenesis, since thymectomy prior to or after PNU treatment abolished lymphomagenesis, whereas grafting of a normal neonatal thymus before PNU treatment restored it. Exposure to PNU for 42 days resulted in the appearance of potentially lymphomatous cells first in the thymus, and overt T-lymphomas subsequently appeared. Such cells seemed to be thymus-dependent, since intrathymic transfer of the thymus cells from 42-day PNU-treated rats induced T-lymphomas much more efficiently than intravenous transfer. Further, grafting of the thymus from 42-day PNU-treated rats into thymectomized rats resulted in T-lymphomas of donor origin without additional PNU treatment. Cells from the spleen or bone marrow from the same donors did not give rise to T-lymphomas irrespective of the route of cell transfer and sublethal irradiation of the recipients. Morphologically atypical cell foci were detected first on the 28th day in the thymus and were most pronounced during the 35th-42nd days. Therefore, the thymus is the essential organ in which the early events of PNU-induced rat T-lymphomagenesis take place.

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Potential risks of gastrointestinal cancers after cholecystectomy were examined among 1238 patients who had had their gallbladders extirpated for benign biliary diseases from 1951 to 1970. The observed deaths between 1953 and 1984 were compared with the expected values which were calculated from death rates in Japan. No appreciable excess mortality was found for stomach cancer, colorectal cancer or pancreas cancer in relation to cholecystectomy. Observed and expected deaths during the whole observation period were 29 vs. 31.58 for stomach cancer, 8 vs. 6.50 for colorectal cancer overall, 5 vs. 3.19 for colon cancer and 3 vs. 3.51 for pancreas cancer. The corresponding figures in the 10 years or more after cholecystectomy were 14 vs. 19.06 for stomach cancer, 5 vs. 4.66 for colorectal cancer and 3 vs. 2.38 for colon cancer. A notably increased mortality from liver cancer was observed, but it was considered to be related not to cholecystectomy itself but to blood transfusion.

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The cell membranes of human melanoma express a tumor-associated ganglioside, GD2. We previously established a human melanoma cell line, M14-A, that metastasizes to the lung, liver, skin, lymph nodes, and abdominal organs of nude mice in addition to forming ascites and pleural effusions. We also reported the successful in vitro production of human IgM monoclonal antibody to GD2. In the present study, we evaluated the GD2 expression of human melanoma cells at the primary and metastatic sites and their reactivity to human monoclonal anti-GD2 antibody in vivo. GD2 was expressed strongly on the melanoma cells from both primary and metastatic sites, except for cells from pleural effusions and ascites. When M14-A-bearing nude mice received systemic injections of the human monoclonal antibody, the anti-GD2 titer in the sera was reduced markedly at 2 hours, whereas the reduction was minimal in sera from tumor-free mice and mice bearing GD2-negative human M24 cells. The immune adherence test confirmed that antibody was fixed on cells of primary subcutaneous M14-A tumors and on their metastases to liver, lung, abdominal organs and skin. These results suggest that this large molecule protein can penetrate the blood-tumor barrier and bind immunologically to antigen-positive melanoma cells in vivo.

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An objective method to evaluate experimental lung metastasis of murine melanoma has been established by sandwich radioimmunoassay using monoclonal anti-melanoma antibody (M2590). The assay system quantitatively detected melanoma antigens metastasized in the lung. The data obtained by radioimmunoassay were consistent with those obtained by the usual colony-counting method. By the use of these detection systems for lung metastasis, we found that only one particular syngeneic monoclonal antibody (M562) recognizing a proteinaceous determinant on melanoma antigen significantly inhibited experimental lung metastasis of melanoma cells (1/7-1/10 of controls), whereas other syngeneic monoclonal antibodies with the same specificity and the same immunoglobulin class or control antibody did not. It is therefore strongly suggested that the molecule recognized by M562 antibody plays an important role in lung metastasis of melanoma cells.

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The antitumor effect on Meth-A fibrosarcoma in BALB/c mice of a synthetic cord factor, 6, 6'-di-O-decanoyl-α, α-trehalose (designated as SS554), was examined. Only intratumoral injection had a curative effect; subcutaneous, per oral, or intravenous routes had no such effect. The co-presence of an oily vehicle has been shown to be necessary for antitumor activity of a natural cord factor. When SS554 was examined in suspensions of sesame oil, squalane, squalene or sesame oil and water emulsion, a 60% cure rate was achieved. However, no such effect was obtained with a suspension in Tween-PBS or a solution. It should also be noted that sequential but independent administrations of SS554 and oil were found to be as effective as the simultaneous administration of oil and SS554 in emulsion form. In the case of the emulsion, the amount of sesame oil necessary was over 10%, or 0.01ml in absolute terms. Cures were obtained in a dose-dependent manner by injection of SS554 in amounts in excess of 1mg. The effect of the time of administration was also examined; the best result was obtained when intratumoral injection was done on day 3 after tumor implantation. Mice cured by SS554 exhibited growth inhibition and rejection of rechallenged Meth-A cells. However, this immunity was specific; it did not extend to a rechallenge with RL_??_-1 leukemia cells.

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