Effect of mass rearing on life history traits and inbreeding depression in the sweetpotato weevil (Coleoptera: Brentidae).

Inadvertent selection is an important genetic process that frequently occurs during laboratory culture and maintenance of biological control agents and other beneficial organisms used in procedures such as the sterile insect technique (SIT). We investigated effects of mass rearing and inbreeding depression on life history traits (number of progeny emerging from host plants, body weight, developmental period, and starvation tolerance) in the sweetpotato weevil, Cylas formicarius elegantulus (Summers) (Coleoptera: Brentidae). The effect of inbreeding was measured by comparing the results obtained from the full-sib crosses with those obtained from nonkin crosses in both wild and mass-reared strains. The mass-reared strain had more progeny than the wild strain. The developmental period of mass-reared strain was shorter than that of the wild strain. Other traits did not differ significantly between strains. We detected inbreeding depression effects on numbers of progeny, and the effects were more pronounced in the mass-reared strain. Hence, laboratory adaptation to mass rearing can produce changes in important biological attributes of sweetpotato weevils.

Assessment of effect of partial sterility on mating performance in sweetpotato weevil (Coleoptera: Curculionidae).

The sterile insect technique (SIT) is widely used to suppress or eradicate target pest insect populations. Although the effectiveness of SIT depends on the ability of released sterile males to mate with and inseminate wild females, the use of gamma radiation to induce sterility negatively impacts reproductive cells as well as somatic cells. Consequently, sterilization by irradiation drastically diminishes mating performance over time. In the current study, we evaluated the effect of irradiation dose intensity on fertility, mating propensity, and mating competitiveness in sweetpotato weevil, Cylas formicarius elegantulus (Summers) (Coleoptera: Curculionidae), for 16 d after irradiation. Although the mating propensity of males irradiated with 200 Gy, the dose currently used to induce complete sterility of C. f. elegantulus in the SIT program in Okinawa Prefecture, was equal to that of nonirradiated weevils for the first 6 d, the mating propensity of males irradiated with doses between of 75 and 150 Gy was maintained for the first 12 d. The potential fertilization ability of weevils was highly depressed compared with the control weevils, even in those treated with 75 Gy. Mating performance was severely compromised in weevils that were irradiated with a dose of 100 Gy or more. These results demonstrate that partial sterilization can be highly advantageous in eradication programs for the sweetpotato weevil. We discuss the advantages of the application of partial irradiation in insect eradication programs.

Effect of irradiation on mating ability in the male sweetpotato weevil (Coleoptera: Curculionidae).

The sterile insect technique (SIT) is widely used for suppressing or eradicating target pest insect populations. The effectiveness of SIT depends on the ability of released sterile males to mate with and inseminate wild females. Irradiation is the effective manner to sterilize mass-reared insects. The negative impacts of this procedure are not limited to damage on reproductive cells. Gamma-radiation damages the epithelial tissue of midgut, which affects the alimentation in insects. Irradiated males alter their mating behavior over time because of the depression of metabolic activity by sterilization. In this study, we evaluated the male mating performance and sexually compatibility of irradiated male Cylas formicarius elegantulus (Summers) (Coleoptera: Curculionidae) with a 200-Gy dose, as currently used in the SIT program in Okinawa Prefecture, throughout 16 d after irradiation in the laboratory. The mating ability of irradiated males did not differ from that of control males for about a week. However, the mating ability of irradiated male drastically decreased thereafter. We consider that irradiated male C. formicarius elegantulus with a 200-Gy dose had no major effect on male mating behavior approximately for a week after irradiation.

Prognostic value of nucleolar protein p120 in patients with resected lung adenocarcinoma.

PURPOSE: In this study we investigated the prognostic significance of proliferation-associated nucleolar protein p120 in primary resected lung adenocarcinoma because it reflects tumor growth fractions in vitro. PATIENTS AND METHODS: Expression levels of p120 in tumors were assessed by immunohistochemistry in 74 patients who underwent radical resection. With clinical follow-up data, the prognostic significance of p120 calculated by labeling indices was evaluated using the Cox proportional hazards model. RESULTS: p120 protein was clearly detected in nucleoli of adenocarcinoma cells. Its expression levels widely varied in each sample from 8.5% to 67. 2%, with a mean +/- SD of 35.2% +/- 15.1%. No significant correlation was found between expression levels of p120 and clinicopathologic factors. However, the expression levels of p120 were negatively correlated with the tumor doubling time calculated with retrospective chest roentgenograms. Using a cutoff value of 35% in the labeling index of p120, patients with high expression of p120 experienced early recurrence and shorter survival compared with those who had low expression of p120. Multivariate analysis showed that p120 served as an independent, as well as the strongest, prognostic factor for resected lung adenocarcinoma. CONCLUSION: This report provides the first evidence that expression levels of p120 in tumor tissues can be used as an independent and powerful prognostic marker for resected lung adenocarcinoma.

Expression of nucleolar protein p120 in human lung cancer: difference in histological types as a marker for proliferation.

The function of proliferation-associated nucleolar protein p120 is unclear. A recent report that a yeast protein, NOP2, 67% homologous to human p120, is up-regulated during the onset of growth and influences the morphology of the nucleolus supports the notion that this protein could serve as a marker for proliferation in neoplastic cells. Lung cancer is characteristic in that different histological types show different biological features. We attempted to evaluate the levels of p120 expression in resected human lung cancer tissues of different histological types and the relation of p120 expression and cell proliferation using human lung cancer cell lines. When 37 frozen specimens of human lung cancer and normal lung were stained with a p120 monoclonal antibody, the nucleoli of cancer cells were positively stained, whereas a few macrophages in normal lung revealed only weak staining. The labeling index of p120 in squamous cell carcinoma (67.7 +/- 12.4%) was significantly higher than that in adenocarcinoma (35.3 +/- 12.6%) or in large cell carcinoma (30.1 +/- 17.3%; P < 0.01). In six human lung cancer cell lines and one normal lung fibroblast cell line cultured in vitro, there was a significant correlation between S-phase fraction and p120 mRNA (r = 0.851, P < 0.02)/p120 protein (r = 0.869, P < 0.01) or between doubling time and p120 protein (r = -0.928, P < 0.01). In the context of the reports that indicate higher [3H]thymidine incorporation and shorter doubling time in the squamous cell carcinoma, these results indicate that p120 can be a marker for proliferation in human lung cancer cells in vivo and in vitro, and that it has an important function in the cell cycle of tumor proliferation.

Ubenimex (Bestatin), an aminopeptidase inhibitor, modulates protein kinase C in K562 cells.

Ubenimex (Bestatin) is a potent inhibitor of aminopeptidases (APase) including APase N (EC 3.4.11.2), a widely distributed membrane-bound metalloprotease. Binding of Ubenimex (UBX) to cells has been implicated in a variety of its biological activities, while little evidence has yet been provided as to any subsequent mechanisms of intracellular signal transduction. We now examined the possible involvement of protein kinase C (PKC), a key regulator in transmembrane signaling. Human leukemia K562 cells were cultured in the presence or absence of UBX (1 to 50 micrograms.ml-1, 1 to 72 h), and the subcellular distribution as well as phorbol-12, 13-dibutyrate (PDBu)-induced redistribution of PKC activities were assessed. The membrane-bound enzymatic activity tended to increase in the presence of UBX, while a significant loss of the activity was demonstrable upon subsequent exposure to PDBu (100 nM, 10 min) in both the cytosolic and membrane fractions. Specific binding of [3H]PDBu to intact K562 cells was also down-modulated with UBX concentration- and time-dependently, suggesting loss of PKC enzyme protein on the cell surface. Western blot analysis of the total cell extracts disclosed no appreciable alteration in the amount of PKC protein. APase inhibition with UBX was observable independently of PKC modulation. The present findings were discussed with reference to the possible differential mechanisms of PKC-mediated regulation of cellular responses depending on cell types.

Protein kinase C activity in human leukemia cell lines with reference to sensitivity to antineoplastic agents.

Protein kinase C (PKC) regulates many cellular processes. In view of its possible relevance to the drug resistance, the levels of PKC activity were assessed in human leukemia cell lines with reference to the sensitivity to antineoplastic agents. K562/ADM exhibited approximately 2-fold higher levels of PKC activity as compared with the parental K562. After a 1-hr preincubation with Adriamycin (ADM) (0.5, 1, 10 microM), PKC activity in K562 tended to increase dose-dependently, while no substantial alteration was found in K562/ADM. Cisplatin (CDDP) or etoposide was of no effect. The activity in THP-1/E was slightly lower than THP-1, and the basal level stayed unchanged with any one of the above drugs. These results suggest that in K562 increase in PKC activity with ADM may play a role in the process of acquisition of resistance.

Reduced topoisomerase II-mediated DNA cleavage in VP-16 resistant human leukemic cell line.

Drug resistance in the VP-16 resistant human leukemic cell line (THP-1/E) was studied the possible relevance of topoisomerase II activity. Strand-passing activity in crude nuclear extract from sensitive and resistant cells was comparable and equally sensitive to inhibition by VP-16. However, it was demonstrated that VP-16-mediated pBR322 DNA cleavage in the presence of nuclear extract from resistant cells was reduced to one-tenth of that from sensitive cells. These results suggested that the resistance of THP-1/E cells to VP-16 was due to reduced DNA cleavage activity.

Characterization of resistance to VP-16 in human leukemic cell line.

Resistance mechanism was studied in the VP-16-resistant human leukemic cell line (THP-1/E) which was developed by continuous drug exposure. The drug uptake and efflux studies revealed no decrease in net cellular drug accumulation. VP-16-induced DNA single- and double-strand breaks in the whole THP-1/E cells decreased significantly compared to the sensitive counterpart as assessed by alkaline elution methods. Decrease in DNA SSBs was also observable in the isolated nuclei from the THP-1/E cells. The resistance to VP-16 in THP-1/E appeared to be independent of altered membrane permeability, and more likely to be associated with decreased VP-16-mediated DNA cleavage.

Establishment of an etoposide (VP-16)-resistant subline of THP-1 human monocytic leukemia cell line.

A VP-16-resistant subline was established from THP-1 human monocytic leukemia cells by subculturing in stepwise increasing concentrations of the drug. The resistant cells (THP-1/E) were capable of sustaining continuous growth in 1.0 microgram/ml VP-16. The 50% inhibition dose (IC50) was 1.4 micrograms/ml or a 35-fold of the parent cells. A more than 18-fold IC50 was also obtained with teniposide (VM-26). However, no substantial cross-resistance was observed with 5 other antineoplastic drugs, IC50 values being limited below several times of THP-1.

Conversion of Lewis lung carcinoma into ascitic form.

Lewis lung carcinoma (3LL), which has been most frequently used for various investigations of cancer, was converted to an ascitic form designated 3LL-SA. Ascites tumor cells showed a mixed population of single cells and about 10% islands which were made up of 2 to about 50 cells. Transplantability was 100%. The biological and metastatic capacities were preserved in this line as shown by its ability to form hemorrhagic and necrotic tumors, and by its multiple lung metastases. Moreover, histological and ultrastructural characteristics of this tumor line were identical to those of the parental 3LL. Thus, it can be seen that 3LL-SA will be a useful tool for the study of cancer.

Antitumor activity of cyclophosphamide and lipopolysaccharide in tumor-bearing mice pretreated with BCG.

Antitumor effects of cyclophosphamide (CY) and lipopolysaccharide (LPS) were investigated in BCG-treated mice. C3H/He mice and CDF1 mice were injected with BCG and were inoculated subcutaneously with syngeneic mouse hepatoma and mastocytoma P815 respectively. A subsequent injection of LPS caused hemorrhagic necrosis and retarded growth of tumor. When mice were treated with LPS plus suboptimal dose of CY, tumor growth was retarded and survival time was prolonged. The antitumor effects were more remarkable when mice were treated with CY prior to the injection of LPS. Without BCG pretreatment, LPS showed no antitumor activity in mice. Sera from mice treated with BCG plus LPS was cytotoxic for cultured tumor cells. However treatment of mice with CY did not increase the in vitro cytotoxicity. In this experimental condition, CY had no effect on delayed type hypersensitivity when evaluated by the footpad reaction to purified protein derivative (PPD). These results seem to indicate that the antitumor effects of the treatment with CY and LPS in BCG-treated mice are mediated by the reduction of tumor burden by CY and a serum factor induced by LPS.

Antitumor activity of lipopolysaccharide in tumor-bearing mice pretreated with BCG.

The antitumor activity of lipopolysaccharide (LPS) was investigated in BCG-treated mice. C3H/He mice and CDF1 mice were injected with BCG and then were inoculated with syngeneic mouse hepatoma MH134 and mastocytoma P815 respectively. Hemorrhagic necrosis and retarded growth of tumor were observed after an intravenous (i.v.) injection of LPS, when tumor cells had been inoculated subcutaneously (s.c.). However an intraperitoneal (i.p.) injection of BCG plus LPS did not increase the mean survival time of mice that had been inoculated with tumor cells i.p. Sera from mice that had been treated with BCG plus LPS i.v. were cytotoxic for cultured tumor cells. These results seemed to indicate that growth-inhibitory effects of LPS on tumors inoculated s.c. were mediated by a humoral factor.

Tumor histology and the immunoregulatory T lymphocyte subsets in lung cancer patients.

The immunoregulatory T lymphocyte subsets (CD4+, CD8+) in 39 patients with primary lung cancer were analyzed as for the possible correlation with tumor histology. Compared to the healthy controls (n = 36), cancer lymphocytes were generally characterized by a higher proportion of CD8+ subset (p less than 0.01) with no difference in either CD4+ subset or CD3+ cells. There was, however, a significant difference (p less than 0.05) between one extreme of epidermoid carcinoma with the highest CD8+ and the lowest ratio (CD4+/8+) and the other end of adenocarcinoma with the lowest CD8+ and the highest ratio. Large cell and small cell carcinomas were of the intermediate values. A spectrum of the subset marker profiles was thus found in associated with tumor histology. A diversity in the host immune status was suggested in primary lung cancer, although clinical implication remains to be clarified.

cis-Diamminedichloroplatinum (CDDP)-fosfomycin (FOM) combination in lung cancer patients with respect to the peripheral T lymphocyte subsets.

An antibiotic FOM was found to be preventive of the side effect of an antineoplastic drug CDDP on the peripheral T lymphocytes in lung cancer patients. Whereas finding a significant decrease in T3+ cells (p less than 0.01) and T4+ subset (p less than 0.05) with CDDP alone, the initial levels of these cell populations were kept unchanged in combination with FOM. T8+ subset showed no substantial change. A protective effect of FOM on T4+ subset was suggested to be an additional aspect of its action at least in combination with CDDP.

Imbalance of T cell subsets in cancer patients and its modification with bestatin, a small molecular immunomodifier.

The peripheral T lymphocyte subsets and natural killer (NK) cells of patients with cancer were studied by monoclonal antibody assays in comparison with those of non-cancer individuals. An imbalance of immunoregulatory T cell subsets was frequently found in the group of cancer patients (n = 26), being characterized by a relatively high proportion of OKT8+ cells (45.0 +/- 12.0%, p less than 0.01) and a low OKT4+/OKT8+ ratio (1.29 +/- 0.56, p less than 0.05). T cell level showed no significant difference as assessed by either OKT3 or rosette formation with sheep erythrocytes (E). The effect of bestatin was examined in 10 of these cancer patients. The relative proportion of T cell subsets tended to normalize 2 to 6 weeks after starting the daily doses of 30 mg per body. The mean percentage of OKT8+ cells decreased from 47.2 to 33.4 (p less than 0.01), while the helper to suppressor ratio increased from 1.18 to 1.79 (p less than 0.01). A significant increase was also found in the percentage and number of OKT4+ cells and HNK-1+ cells after the drug administration, while T cell level tended to converge to a normal range.

Changes in the immunological parameters after a single dose of forphenicinol, a new small molecular immunomodifier.

Forphenicinol [L-2-(3-hydroxy-4-hydroxymethyl-phenyl) glycine, M.W. 197.19] is a derivative of forphenicine, an inhibitor of alkaline phosphatase discovered by Umezawa. In order to find an optimal dose, a single dose of the drug ranging from 10 to 600 mg per body was orally administered to a total of 55 patients (36 cancer, 13 tuberculosis, and 6 others). The possible changes in the percentages of the peripheral T and B lymphocytes, natural killer (NK) activity, and the proliferative response to phytohemaglutinin (PHA) were studied as immunological parameters. A significant effect of forphenicinol was demonstrated in restoring the normal proportion of T and B cells, especially in those who had 'low'-T and/or 'high'-B before administration of the drug. No difference was found between cancer and tuberculosis. The mean percentage of T cells increased from the low initial level of 68.0 to 75.6 in cancer (n = 12, p less than 0.05) or from 63.1 to 78.5 in tuberculosis (n = 7, p less than 0.05), while that of B cells decreased from the high initial level of 34.6 to 26.9 in cancer (n = 7) or from 34.9 to 14.3 in tuberculosis (n = 6, p less than 0.025). The effect of a single dose of the drug tended to disappear by day 8, a peak response being found on day 3 in most cases. With respect to this parameter, an optimal dose was found in a range from 60 to 100 mg. Forphenicinol was rather inhibitory on the NK activity, while it exerted diverse effect on the lymphocyte proliferation. No evidence of adverse effect was observed.