A cell growth inhibitor was isolated from an avian sarcoma virus-transformed rat cell line (77N1), from which we had previously obtained a novel transforming growth factor, TGFγ2. The growth inhibitor (named SGI) was found in cell extract of 77N1 cells and was separable from TGFγ2 by means of ion exchange chromatography. SGI inhibited the DNA synthesis of serum-starved, TGFγ2-stimulated BALB3T3 cells as well as the spontaneous and TGF-induced colony formation of various cells in semisolid agar. We present evidence that SGI is distinct from the ubiquitous growth modulator TGFβ, and we discuss the possible role of SGI in the neoplastic cell proliferation.

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In the course of screening for inhibitors of reverse transcriptase, we have isolated an inhibitor from a strain of Nocardia and identified it as sakyomicin A. The antibiotic blocks avian myeloblastosis virus reverse transcriptase reaction: IC₅₀ was ca. 30μg/ml by the method employed. The drug affects proliferation of HTLV-III/LAV in HTLV-I-carrying MT-4 cells: ca. 60% inhibition was observed at an antibiotic concentration of 1.0μg/ml and ca. 20% inhibition at 0.1μg/ml, and there was no significant cytotoxicity.

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The developmental potential of a mutator strain Ara C^r (1.5)4 of mouse teratocarcinoma cells was examined by injecting these cells into host blastocysts. Analysis of developing embryos at 9.5 days of gestation showed the mutator strain gave chimeras at a rate comparable with that of the parent strain. However, most of these chimerice mbryos with the mutator strain were abnormal, and the extent of abnormality seems to be related to the proportion of the mutator-derived cells in the embryos. When injected embryos were allowed to develop to 14.5 days, the number of developing embryos decreased, and only a few were chimeric in limited tissues. The results suggest that the mutator strain is lethal to early gestational development, and only those chimeras with limited colonization of the strain can develop normally beyond this stage.

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A cloned cDNA segment of 442bp which contains the region coding the N-terminal sequence of rat DNA polymerase β polypeptide was used as a probe in Southern hybridization analysis to identify the gene for this enzyme. This probe hybridized with DNA from mouse and human in addition to rat DNA, and the BamHI fragment containing DNA polymerase β gene sequence was unique in size in each species: 15.8kb for rat DNA, 8.7kb for mouse DNA and 10.1kb for human DNA. DNA extracted from a panel of 12 independent human-mouse somatic cell hybrids was analyzed by Southern blot hybridization with the cloned cDNA probe. The results indicate that the gene for the human DNA polymerase β sequence (POLB) is located on chromosome 8.

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Three patients with malignant lymphoma, two of T-cell type and the other probably also of T-cell type, had an interstitial deletion of the short arm of chromosome 6, del (6)(p21p23), in common in their lymphoma cells. These findings suggest that this new type of chromosome deletion may be a specific marker for T-cell lymphoma and may play an important role in the lymphomagenesis and the expression of the T-cell phenotype.

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Monoclonal antibody NCC-pX-1G (IgG₁, κ) was obtained by the hybridoma technique by immunization of mice with the C-terminal 54 amino acids of the pX protein, made from the 3'-terminal portion of the pX gene conjugated with bovine growth hormone gene transfected in E. coli. NCC-pX-1G recognized 41 kilodalton pX protein of HTLV-I, and immunocytochemically stained HUT102 and other HTLV-I-infected cell lines, but no reaction was observed with non-HTLV-I-infected cell lines or normal human tissue cells.

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The effects of interferons (IFNs) and interleukin 2 (IL 2) on endogenous production of tumor necrosis factor (TNF) were investigated in mice. Production of serum TNF was triggered by iv injection of OK-432 and tested by in vitro cytotoxicity assay. Injection of recombinant IFN-γ with OK-432 or of IFN-α/β, recombinant IFN-β, recombinant IFN-α A/D or recombinant IL 2 six hours before OK-432 enhanced TNF production about 10-fold, which indicated priming actions of these compounds in TNF production. These findings suggest that these compounds could also be used as priming agents for endogenous production of TNF in cancer patients.

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This study was carried out to clarify the promoting effect of glycerol on 4-nitroquinoline 1-oxide (4NQO) tumorigenesis in the lung. Animals used were 80 ddY male mice, 6 weeks old. 4NQO, dissolved in olive oil-cholesterol (20:1) mixture, was injected subcutaneously at a dose of 10mg/kg body weight per mouse. Drinking water contained 5% glycerol. Mice were divided into the following 4 groups of 20 animals each: non-treated mice (group I), mice given glycerol alone (group II), mice given 4NQO alone (group III), mice receiving combined administration of 4NQO and glycerol (group IV). The percent of mice having induced pulmonary tumors and the mean number of tumors per mouse were 2 and 0.10±0.07 (mean±SE), 2 and 0.10±0.07, 9 and 0.45±0.25, and 58 and 2.90±0.62, respectively. A significantly higher rate was seen in group IV, as compared with the 4NQO-treated control. This result showed that glycerol has a promoting action on 4NQO-induced pulmonary tumorigenesis in mice.

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The effects of the newly synthesized polyprenoic acid, 3, 7, 11, 15-tetramethyl-2, 4, 6, -10, 14-hexadecapentaenoic acid (E-5166) on N-2-fluorenylacetamide (FAA)-initiated hepatocarcinogenesis were examined in 6 groups of male ACI rats. The numbers of altered hepatocellular foci in rats of group 1 given a basal diet containing 0.02% FAA for 13 weeks and in rats of group 2 which received E-5166 by gavage (40mg/kg, 3 times/week) at the same time as receiving the FAA diet were almost the same, indicating that E-5166 had no effect at the stage of carcinogen exposure. However, the number of foci in group 4, in which rats were given the basal diet and E-5166 after the termination of the carcinogen exposure, and were sacrificed 16 weeks later, was significantly smaller than that in group 3 maintained on the basal diet alone (P<0.05). The result suggests some anticarcinogenic activity of E-5166, possibly involving the phenotypic expression of the preneoplastic foci. Furthermore, the number of altered foci in rats of group 6 (given the liver-tumor promoter phenobarbital with E-5166 for 16 weeks after the administration of carcinogen) was also significantly smaller than that in rats of group 5, which received the promoter (P<0.05). The incidence of neoplastic nodules of the liver in group 6 at the end of the experiment was also lower than in group 5 (P<0.0014). These results suggest an antipromoting effect of the polyprenoic acid E-5166 on rat chemical hepatocarcinogenesis.

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The distribution, covalent binding and metabolism of radioactive 1-nitropyrene (1-NP) were examined following its oral administration to conventional and germ-free male Wistar rats. With both groups of animals, the liver, kidney, bladder, adipose tissue and gastrointestinal tract had the highest specific radioactivity. However, the maximum concentration of radioactivity occurred at 12hr in conventional rats as compared to 24hr in germ-free animals. This difference may be due to the faster transit time of the intestinal contents through conventional rats. At 48hr after treatment, the covalent binding of 1-NP metabolites was greatest in liver and kidney of conventional rats, while in germ-free rats, substantial binding was also found in the gastrointestinal tract. The mutagenic activity inSalmonella typhimurium TA98 of fecal extracts and urine from conventional rats was greater in the presence of an S9 mix, whereas similar extracts from germ-free animals were more mutagenic in the absence of S9. The major fecal metabolites in germ-free rats were (in order of decreasing concentration): 3-nitropyrenol>1-NP>4, 5-dihydroxy-4, 5-dihydro-l-NP>6-nitropyrenol>8-nitropyrenol. With the exception of 1-NP, similar metabolites were found in the urine as their glucuronide conjugates. In the feces from conventional rats, substantial nitro reduction and N-acetylation occurred with the major metabolites being: 1-NP>1-aminopyrene>8-acetylaminopyrenol>6-acetylaminopyrenol>3-acetylaminopyrenol. The major metabolites identified in the urine from conventional rats were glucuronide conjugates of 6- and 8-acetylaminopyrenol, while the major biliary conjugates indentified were glucuronide conjugates of 4, 5-dihydroxy-4, 5-dihydro-1-NP and 3-, 6-, and 8-nitropyrenol, although the relative proportion of glucuronide conjugates of 6- and 8-aminopyrenol and 6- and 8-acetylaminopyrenol increased in later stages of the biliary excretion. The polar and β-glucuronidase-refractory metabolites, which may be sulfate and glutathione conjugates, remain to be identified.

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Activated c-Ki-ras with a point mutation (GGT to CGT) at codon 12, resulting in the substitution of arginine for glycine, was found in DNA from metastatic pancreatic adenocarcinoma in a lymph node. By means of restriction endonuclease length polymorphism with SacI digestion, we were able to demonstrate that the same point mutation of c-Ki-ras was present in the primary tumor and in metastases in lymph nodes. DNA from the normal spleen of the patient did not have this type of point mutation. Moreover, amplifications of 3- to 6-fold of the activated c-Ki-ras and 50-fold of c-myc were found in the primary tumor and the metastases in the two lymph nodes, indicating that point mutation had occurred at a relatively early stage of the tumor development, before amplification of the gene. This is the first clear demonstration of amplification of activated c-Ki-ras accompanied by amplification of c-myc in both primary and metastatic human tumors in vivo.

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Chromosome studies were carried out on 12 tumors induced by subcutaneous injection of 0.005-0.5mg of 3-methylcholanthrene in female mice carrying Cattanach's X-autosome translocation. Using the asynchronously replicating (hence genetically inactive) X chromosome as a marker, we obtained evidence showing that most or all of these tumors were monoclonal in origin. A single case, in which cell fusion occurred early in tumorigenesis, demonstrated that simultaneous expression of two different X chromosomes is not always incompatible with monoclonality.

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The effects of etoposide (VP-16) on sister chromatid exchange (SCE) and chromosome abnormalities were studied by using human peripheral lymphocytes. This drug produced a significant increase in the SCE frequency and chromosomal aberrations such as breaks, exchanges, and tetraploidy with or without endoreduplication. Analysis of the breakpoints of chromatid deletion with respect to their association with SCE in the metaphases from the second division demonstrated that VP-16-induced deletions arose with little dependence on the site of SCE. It is suggested that chromatid deletions induced by this drug derive from unrepaired chromatid breaks rather than from incomplete exchanges.

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Among normal lymphocytes, T cells can readjust their volume rapidly following initial swelling in a hypotonic medium, whereas B cells do not have this ability. Based on this finding, we examined the volume regulation of malignant cells from 40 patients with lymphocytic and nonlymphocytic malignancies. The T lineage cells were able to regulate their volume in response to hypotonic stress, whereas B lineage cells were not able to do so. In contrast to lymphoid lineage cells, nonlymphocytic leukemia cells as well as undifferentiated cells did not show a consistent tendency in their volume regulation. These results showed that the difference in the ability to regulate cell volume in response to hypotonic stress is available as a marker for identifying the cellular lineage of lymphoid malignancies.

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To evaluate epidemiologically the efficacy of mass screening for uterine cancer, we compared the changes in the age-adjusted death rates from cancer of the uterus from 1969-1972 to 1973-1977 between the high coverage-rate areas and the control areas. The main results were: (a) the decrease in the average age-adjusted death rate from cancer of the uterus was greater in the overall high coverage-rate (20% and over) areas (33.4%) than in the control areas (26.9%), but this difference was not statistically significant, (b) when the high coverage-rate areas were limited to those where the uterine cancer death rate in 1969-1972 was greater than 90% of the average rate of all Japan, the decrease in the average age-adjusted death rate from cancer of the uterus was also greater in these high coverage-rate areas (68.1%) than in the control areas (44.2%) and this difference was statistically significant (P<0.01), (c) when the high coverage-rate areas were limited to municipalities with a population size larger than 5, 000, similar trends were observed. These results suggested that if mass screening for uterine cancer is widely conducted in areas with relatively high mortality rate from uterine cancer, it may be possible to reduce the mortality from this cancer at the community level.

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Phytohemagglutinin (PHA)-induced interleukin 2 (IL-2) production and lymphocyte proliferation were measured in former workers of the Okunojima Poison Gas Factory (poison gas workers), who have a high incidence of lung cancer, and the efficacy of administration of Nocardia rubra cell wall skeleton (N-CWS) was studied. In comparison with normal controls and poison gas workers receiving N-CWS, lymphocyte proliferation in posion gas workers not receiving N-CWS showed a significant decrease, while IL-2 production showed a slight though not statistically significant decrease. When N-CWS was administered to poison gas workers, IL-2 production and lymphocyte proliferation were significantly elevated, with a peak two weeks after administration. N-CWS, by elevating IL-2 production of lymphocytes, is considered to have improved the depression of lymphocyte proliferation.

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Recombinant human inrerferon αA/D (IFNαA/D) is known to be as active on murine cells as on human cells. We studied the antitumor effect of pure IFNαA/D on Meth-A sarcoma subcutaneously transplanted into female syngeneic BALB/c mice. When administered systematically (intraperitoneally), IFNαA/D was only marginally (but significantly, P<0.05) effective in inhibiting tumor growth. With intralesional injection, however, IFNαA/D strongly suppressed the growth of Meth-A sarcoma, even leading to complete tumor regression and to subsequent immunity to Meth-A sarcoma cells in the host mice when the treatment was started early after tumor transplantation and with a high IFNαA/D dose. We also found that treatment of mice with IFNαA/D increased the level of serum α₁-acid glycoprotein, one of the acute-phase proteins.

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