The expression and organization of epidermal growth factor (EGF) receptor gene in cultured human lung cancer cell lines (5 adenocarcinomas, 3 squamous cell carcinomas, 2 small cell carcinomas and 1 large cell carcinoma) have been studied. Two (PC-8 and PC-9) of the adenocarcinomas overproduced EGF receptor mRNA and protein, and exhibited gene amplification, the magnitude of which was comparable to that of A431 cells. Six cell lines (3 adenocarcinomas, 2 squamous cell carcinomas and 1 small cell carcinoma) expressed EGF receptor gene and its product to a significant level without gene amplification, and the other three cell lines were found to be negative as regards expression.

View full abstract

Four female rabbits were given twiceweekly oral inoculation of 2-4×10⁷ cells from a male rabbit lymphoid cell line persistently infected with human T-cell leukemia virus type I (HTLV-I). After 8 weeks, one of them was found to be seroconverted for HTLV-I. Peripheral lymphocytes from the 4 rabbits were cultured in the presence of T-cell growth factor, and a lymphoid cell line with a normal female karyotype was established only from the seroconverted rabbit. This cell line was reactive with a monoclonal antibody to rabbit T-cells and expressed HTLV-I antigens and virus particles.

View full abstract

Fifteen human breast milk samples obtained from mothers seropositive for human T-cell lymphotropic virus type-I (HTLV-I) antigen were kept frozen overnight at -20°. Each milk sample was then co-cultivated with cord lymphocytes obtained from 15 anti-HTLV-I antibody-negative mothers. No HTLV-I antigen-positive cells were detected among the cord lymphocytes subjected to co-cultivation. These results suggest that thawing of frozen breast milk may prevent HTLV-I transmission from mother to child via breast milk.

View full abstract

Two types of DNAs were clonally purified from the virion fraction which was obtained by the cesium chloride density gradient centrifugation of a homogenate of scrapings from benign lesions of typical epidermodysplasia verruciformis. Restriction-enzyme maps were made for these DNAs, and the DNA-DNA hybridization of these cloned DNAs with 25 different types of human papilloma virus DNAs indicated that one of the DNA clones isolated is a new type of human papilloma virus DNA, and the other is the DNA of human papilloma virus type 21 or its subtype.

View full abstract

The effects of physical restraint on the development of Friend erythroleukemia in ddY mice were examined. Restraint was applied by immobilizing the mice in wire cages. In both sexes there was a reduction in the weight of the whole body, thymus and spleen, though the food intake was not reduced. The incidence of leukemia was reduced in the males, but not in the females, while the latent period was prolonged in both sexes. This sex dependency is characteristic of the stress response.

View full abstract

For the purpose of clarifying the relation between hepatitis B virus (HBV) and hepatocellular carcinoma (HCC), a follow-up study of 1, 614 HBV carriers (910 males and 704 females) was conducted at Kure National Hospital from 1970 to 1984. During the follow-up period (40.3 months on average), 247 HBV carriers died. Deaths from HCC and liver cirrhosis (LC) numbered 99 of 168 males (58.9%) and 38 of 79 females (48.2%), the chi-square test revealing no sex difference. Of 142 deaths from malignant neoplasm, HCC accounted for 52 of 96 males (54.2%) and 19 of 46 females (41.3%), the chi-square test again revealing no sex difference. The adjusted odds ratio of death from HCC among HBV carriers (1, 614) with respect to HBV non-carriers (176, 909) in this hospital during the study period (14-years) was 9.52 (males 7.94, females 13.39). The expected number of deaths was calculated based on the population of Hiroshima Prefecture (1978-1980) as a standard. The adjusted O/E (observed number/expected number) ratio of death from HCC was 6.66 for males and 12.13 for females, and the adjusted O/E ratio of death from LC was 5.41 for males and 11.02 for females. These findings suggest that HBV is a high risk factor of both HCC and LC, and, unlike the general population, female HBV carriers may have a rather higher risk of death from HCC and LC than male HBV carriers.

View full abstract

Treatment of cloned low-metastatic Lewis lung carcinoma cells (P-29) with dimethylsulfoxide or butyric acid resulted in enhancement of their lung-colonizing ability. This was accompanied with increases in cathepsin B activity, the production of plasminogen activator, and adhesiveness, mainly heterotypic adhesion (adhesion to monolayers of endothelial cells) of dimethylsulfoxide-treated cells and homotypic aggregation of butyric acid-treated cells. Treatment of P-29 cells with 8-bromo-adenosine 3':5'-cyclic monophosphate (8-bromo-cyclic AMP) also resulted in increases in cathepsin B activity and the production of plasminogen activator. However, it did not enhance either heterotypic adhesion or homotypic aggregation of the cells. The lung-colonizing ability of 8-bromo-cyclic AMP-treated P-29 cells was examined after their intravenous injection into male C57BL/6 mice. It was found that these cells did not have enhanced lung-colonizing ability. These results suggest that high activities of proteolytic enzymes such as cathepsin B and plasminogen activator in tumor cells are not sufficient alone for completing the metastatic process, but that other properties of tumor cells such as adhesiveness are also necessary.

View full abstract

Antigenic variations of carcinoembryonic antigens (CEAs) produced by 8 human tumor cell lines of various organ origins-4 derived from colonic, one from gastric, one from pancreatic, and 2 from lung cancers-were investigated on the basis of reactivity with several monoclonal antibodies recognizing either the peptide or the carbohydrate moiety of the CEA molecule by using a sandwich-type solid-phase radioimmunoassay (RIA). CEAs from all the cell lines revealed nearly uniform reactivities with the monoclonal antibodies recognizing the peptide epitopes, and no difference was observed between the reactivities of CEAs released into culture medium (m-CEAs) and of those extracted from cells (c-CEAs). On the other hand, with each of 4 monoclonal antibodies recognizing the carbohydrate epitopes, the reactivities of CEAs were found to be highly variable from one cell line to another, and a marked difference was detected between the reactivities of m-CEA and of c-CEA in every cell line. In general, c-CEA reacted much more strongly than m-CEA with these antibodies. The reactivities of some of the CEAs with 2 out of 4 antibodies to sugar epitopes increased significantly after treatment of CEAs with neuraminidase. These results suggest that distinct structural changes in the carbohydrate moiety may occur during the releasing process of CEA from cells, and that, in some cases, some epitopes may be masked by attachment of sialic acid residues.

View full abstract

Monoclonal antibodies with fine specificities distinguishing alpha-fetoproteins of hepatoma (HEP-AFP) and yolk sac tumor (YST-AFP) origin have been obtained. These murine antibodies were produced by hybridomas made by fusion of X63-Ag8.653 myeloma cells with BALB/c spleen cells immunized with either HEP-AFP or YST-AFP and selected for their differential association with these antigens on the basis of Scatchard plot analysis. Three monoclonals (MA120, MA132 and MA136) selectively reacted with HEP-AFP. Their reactivity with YST-AFP was low. One monoclonal (MA122) reacted strongly with YST-AFP, whereas the reaction with HEP-AFP was significantly less strong. The difference in the association constants of these antibodies for the two AFPs appeared to be due to their specificity for the carbohydrate portions of the AFPs, which are different, at least in part. Indirect immunoperoxidase staining confirmed that MA122 was able to stain sections of an infantile embryonal carcinoma, but not of hepatoma.

View full abstract

Medullasin, a serine protease in granulocytes, has been shown to stimulate human natural killer cell activity through its proteolytic activity, without interferon induction. The protease is considered to exert its effect directly on large granular lymphocytes, because firstly the extent of activation of natural killer cell activity by medullasin was the same between peripheral blood lymphocytes and purified large granular lymphocytes, and secondly, addition of medullasin-treated lymphocyte fractions containing few large granular lymphocytes to the large granular lymphocyte fraction failed to enhance the natural killer cell activity of that fraction. Studies employing inhibitors of DNA, RNA and protein synthesis showed that both RNA and protein synthesis, but not DNA synthesis of lymphocytes are necessary for the enhancement of natural killer cell activity by medullasin. These results indicate that medullasin in granulocytes enhances the natural killer cell activity by directly stimulating large granular lymphocytes to induce certain protein(s).

View full abstract

An experimental tumor system consisting of single cells, spheroids, and solid tumors was developed using the EMT6/KU cell-line for evaluation of new hypoxic cell sensitizers. This paper describes the radiation dose-survival curves of the system and the effects of four sensitizers [misonidazole, Ro 03-8799, KB-11 (a sulfonyltetrazole derivative), and DNIE (a dinitroimidazole derivative)] in this system. Dose-survival curves of the spheroids varied significantly depending on the irradiation conditions, but it was found that the spheroids could model the solid tumors when they were irradiated in flat-bottomed flasks. These spheroids and solid tumors contained substantial fractions of hypoxic cells, and hence were suitable for testing hypoxic cell sensitizers. Misonidazole at a concentration of 1mM or 1mmol/kg showed a constant enhancement ratio (ER) of 1.55 in all of the systems. The ERs of the other three compounds for single cells, spheroids, and solid tumors were 2.1, 1.9, and 1.65, respectively, for Ro 03-8799 (1mM or 1mmol/kg); 2.6, 1.6, and 1.0, respectively, for KB-11 (0.5mM or 0.5 mmol/kg); 1.8, 1.2, and 1.1, respectively, for DNIE (0.5mM or 0.5mmol/kg). These results indicated that the ER for spheroids is closer to the ER for solid tumors than is the ER for single cells in most cases. It was also suggested that an efficient sensitizer in vivo shows little or no difference between its ER for single cells and that for spheroids.

View full abstract

The antimetastatic effect of biological response modifiers (BRM) in a new experimental mouse model was studied. Intratumoral administration of BRMs (PSK, OK-432, interferon αA/D) strongly inhibited the growth of Meth-A solid tumors in male BALB/c mice and led to a complete regression of tumors and resistance to reinoculated tumors. Subsequently, the antimetastatic effect of BRMs was examined in the “double grafted tumor system, ” in which mice first received simultaneous intradermal inoculations of Meth-A in the right (10⁶ cells) and left (2×10⁵ cells) flanks and were then injected with BRMs in the right tumor on day 3. PSK and interferon (IFN) significantly inhibited the growth of the left (non-treated) tumor. This finding suggests that intratumoral BRM immunotherapy in one region has an effect on tumor growth in another region. Immunized spleen cells were taken from mice which had been cured by the intratumoral administration of BRMs and had rejected reinoculated tumors. One hour after intravenous injection of cyclophosphamide (2 mg/mouse), immunized spleen cells (2×10⁷cells/mouse) were injected into the Meth-A tumor on day 3. Adoptive transfers of PSK and IFN immunized spleen cells caused the complete regression of Meth-A tumors. These results suggest that the intratumoral administration of BRMs might induce cytotoxic cells in the left non-treated tumor of the “double grafted tumor system” and bring about the regression of metastatic tumors.

View full abstract

Saframycins Yd-1 and Y3, which have an amino functional group in the side chain, were recently obtained by a directed biosynthesis. Twenty-eight side chain-modified chemical derivatives were prepared from these saframycins, and their in vitro and in vivo antitumor activities were studied. Among these new derivatives, three saframycins, namely, two N-acyl derivatives, pivaloyl- and n-caproylsaframycin Y3, and one water-soluble type, saframycin Yd-1•HCl, were found to show marked antitumor activity against L1210 mouse leukemia cells. Further studies of these saframycin derivatives using B16-F10 melanoma and Lewis lung carcinoma indicated that all three saframycins are also active against B16-F10 melanoma; saframycin Yd-1•HCl showed the greatest prolongation of survival time. Marked inhibition of spontaneous metastasis of Lewis lung carcinoma was observed in mice treated with these new derivatives. Structure-activity relationships among these semisynthetic saframycins are discussed.

View full abstract