Modulation of apoptosis and Bcl-2 expression by prostaglandin E2 in human colon cancer cells

Previously, we have shown that forced expression of prostaglandin endoperoxide synthase-2 [also called cyclooxygenase (COX) 2] leads to inhibition of programmed cell death in intestinal epithelial cells. More recently, we have demonstrated that growth of human colonic cancer xenografts is inhibited by treatment with a highly selective COX-2 inhibitor in tumors that express COX-2 (HCA-7) but not in those that lack COX-2 expression (HCT-116). To explore the biochemical mechanisms involved in these effects, we have evaluated the role of COX-2-derived eicosanoid products on programmed cell death in human colon cancer cells. Here we report that PGE2 treatment of human colon cancer cells leads to increased clonogenicity of HCA-7, but not HCT-116 cells. Treatment with a highly selective COX-2 inhibitor (SC-58125) decreases colony formation in monolayer culture and this growth inhibition was reversed by treatment with PGE2. Additionally, PGE2 inhibits programmed cell death caused by SC-58125 and induces Bcl-2 expression, but did not affect Bcl-x or Bax expression in human colon cancer (HCA-7) cells. Therefore, decreased cell death caused by PGE2 would enhance the tumorigenic potential of intestinal epithelial cells. Thus, these results may help to explain a component of the mechanism by which COX inhibitors prevent colorectal cancer in humans.

Studies on the genotoxicity of molybdenum salts in human cells in vitro and in mice in vivo

Molybdenum is an essential element in plants and animals as a cofactor for enzymes. Molybdenum trioxide is used in metallurgical processes, in cosmetics as a pigment, and in contact lens solution, yet limited information is available on molybdenum genotoxicity. In the present study the micronucleus (MN) assay in human lymphocytes and mouse bone marrow and the dominant lethal assay in mice were used to assess the genotoxic effects of molybdenum salts in vitro and in vivo. Two salts of molybdenum were tested in whole blood cultures. Ammonium molybdate was more potent than sodium molybdate in causing a dose-dependent decrease in viability and replicative index and an increase in MN formation in binucleated lymphocytes (P < 0.001). A dose-response in both kinetochore-positive MN (caused by chromosome lagging) and kinetochore-negative MN (associated with chromosome breakage) was observed. Based on the results of a toxicity study of sodium molybdate, two doses, 200 and 400 mg/kg, were assessed in the bone marrow MN assay in mice (two i.p. injections 24 and 48 hr prior to euthanasia). A modest but statistically significant increase in MN frequency in polychromatic erythrocytes was observed (P < 0.05). The same treatment protocol was used to analyze dominant lethality. A dose-dependent increase in postimplantation loss represented mostly by early resorptions was observed the first week after treatment (P = 0.003). These preliminary data suggest that sodium molybdate induces dominant lethality at the postmeiotic stage of spermatogenesis. Overall, molybdenum salts produced moderately positive results both in vitro in human cells and in vivo in mice.

Expression of anti-CD4 human/murine chimeric antibody and their killer tumor activity

From the mouse hybridoma cell line secreting an anti-CD4 monoclonal antibody (McAb), total RNA was prepared. The VH and VL genes were amplified by RT-PCR with family specific primer pairs. The PCR products were cloned into pGEM-T vectors, then tranfected into JM109. The VH and VL genes were analyzed by automatic DNA sequencer. According to Kabat classification, the VH and VL genes belong to the mouse Ig heavy subgroup II (A) and kappa chain subgroup III, respectively. The VH and VL genes were subcloned into p gamma 1-Expr and p kappa-Expr respectively, then transfected into XL2-Blue. The VH- p gamma 1 and VL- p kappa were transfected by electroporation into mouse myeloma cell X63Ag8. 653. The transfectoma cells were selected by G418 screening, and then supernatant of cultured transfectoma were analyzed by ELISA and immunofluorescence techniques. We have acquired transfectoma cells secreting anti-CD4 chimeric antibodies. These chimeric antibodies are able to kill tumor cells specifically in vitro.

Immunoregulation of lupus-like NZB/W F1 mice by anti-murine IL-1 alpha, IL-6 antibodies

Anti-murine IL-1 alpha, IL-6 antibodies were intra-peritoneally injected to the lupus-like NZB/W F1 mice of 4 months with the dosage of 10 micrograms per day for three days and then per month for three months. The mice were killed at the age of 11 months. The results showed that the treatment of the dosage could not absolutely prevent lupus nephritis--it could alleviate proteinuria, obviously reduce the levels of serum IL-1 alpha and inhibit the secretion of IL-1 alpha by celiac macrophage. As to the level of IL-6 and TNF-alpha no significant change was observed.

A selective cyclooxygenase 2 inhibitor suppresses the growth of H-ras-transformed rat intestinal epithelial cells

BACKGROUND & AIMS

Constitutive expression of cyclooxygenase 2 (COX-2) has been found in 85% of colorectal cancers. Ras mutations are found in 50% of colorectal adenocarcinomas. The aim of this study was to determine the role of COX-2 in ras-induced transformation in rat intestinal epithelial (RIE) cells.

METHODS

Cell growth was determined by cell counts. The expression of COX-2 was examined by Northern and Western analyses. For tumorigenicity assays, cells were inoculated into dorsal subcutaneous tissue of athymic nude mice. DNA-fragmentation assays were performed to detect apoptosis.

RESULTS

The expression of COX-2 was increased in RIE-Ras cells at both messenger RNA (9-fold) and protein (12-fold) levels. Prostaglandin I2 levels were elevated 2.15-fold in RIE-Ras cells. Serum deprivation further increased COX-2 expression 3.8-fold in RIE-Ras cells. Treatment with a selective COX-2 antagonist (SC58125) inhibited the growth of RIE-Ras cells through inhibition of cell proliferation and by induction of apoptosis. SC-58125 treatment reduced the colony formation in Matrigel by 83.0%. Intraperitoneal administration of SC-58125 suppressed RIE-Ras tumor growth in nude mice by 60.3% in 4 weeks. SC-58125 treatment also induced apoptosis in RIE-Ras cells as indicated by increased DNA fragmentation.

CONCLUSIONS

Overexpression of COX-2 may contribute to tumorigenicity of ras-transformed intestinal epithelial cells. Selective inhibition of COX-2 activity inhibits growth of ras-transformed intestinal epithelial cells and induces apoptosis.

[Simulation of a decoupling generalized predictive control algorithm for temperature-humidity system]

A decoupling generalized predictive control algorithm was presented in this paper. This algorithm was proposed to control the temperature-humidity system of a practical air-conditioning environmental chamber. By introducing absolute humidity as an intermediate variable, temperature and humidity of the system can be decoupled. Then the two decoupled systems are controlled by generalized predictive control (GPC) algorithm at different sample rates. Many simulation experiments demonstrated the effectiveness of the algorithm. Besides, decoupling of temperature and humidity will be extremely helpful to the application of GPC on the real system. This is also the effective method to control the temperature and humidity system.

Molecular cloning and sequencing of the cDNA encoding mouse glutamate-cysteine ligase regulatory subunit

Reverse transcription-polymerase chain reaction (RT-PCR) was used to amplify and clone the regulatory subunit of mouse glutamate-cysteine ligase (Glclr) using primers adapted from the published rat Glclr cDNA sequence, and from mouse genomic DNA. Amplified cDNA was cloned into a plasmid vector, and additional RT-PCR reactions coupled with 3' RACE were used to amplify and sequence 3' regions covered by the rat primer. Comparison of the mouse Glclr cDNA sequence and predicted protein sequence with that of rat Glclr and human GLCLR revealed extensive homology in cDNA and amino acid sequences among these species.

Mannan-binding lectin in the sub-Saharan HIV and tuberculosis epidemics

Inherited deficiency of mannan-binding lectin (MBL) has been shown to predispose to infections. Conversely, it has also been suggested that MBL might facilitate the uptake of certain intracellular microbes. The aim of this study was to investigate whether MBL plays a role in the HIV and tuberculosis epidemics in Africa. Thus, the authors determined the MBL serum concentration in 173 HIV infected patients (150 with concomitant tuberculosis), 94 patients with tuberculosis without being HIV infected, and 113 controls from Tanzania. The frequency of MBL deficiency was significantly increased in HIV infected patients compared with controls (12.1% and 3.5%, respectively). The frequency of patients deficient of MBL did not differ between controls and HIV negative patients with tuberculosis. However, HIV negative patients with tuberculosis had significantly higher MBL levels than both controls and HIV infected patients with or without tuberculosis. These results indicate that low levels of MBL are associated with increased risk of sexually transmitted HIV infection in Africans. By contrast, high levels of MBL may be involved in the pathogenesis of tuberculosis in immunocompetent individuals.

Prediction bounds for random shelf-lives

Every drug product requires indication of a shelf-life on the immediate container label. The labelled shelf-life is usually determined by a stability analysis with several batches of the drug product. Because of the existence of batch-to-batch variation, the true shelf-lives of different batches differ and can be treated as random variables. To obtain a single labelled shelf-life applicable to all future batches of the drug product, we propose to use a prediction bound of the random shelf-life of a future batch. Under some assumptions, the proposed labelled shelf-life (prediction bound) is lower than the true random shelf-life with a probability approximately equal to a pre-assigned level. For illustration, we provide an example concerning a new drug application stability analysis conducted in a pharmaceutical company. We also discuss an application of our technique to the problem of clean-up of contaminated soils.

Statistical methods for two-sequence three-period cross-over designs with incomplete data

In clinical trials, and in bioavailability and bioequivalence studies, one often encounters replicate cross-over designs such as a two-sequence three-period cross-over design to assess treatment and carry-over effects of two formulations of a drug product. Because of the potential dropout (or for some administrative reason), however, the observed data set from a replicate cross-over design is incomplete or unbalanced so that standard statistical methods for a cross-over design may not apply directly. For inference on the treatment and carry-over effects, we propose a method based on differences of the observations that eliminates the random subject effects and thus does not require any distributional condition on the random subject effects. When no datum is missing, this method provides the same results as the ordinary least squares method. When there are missing data, the proposed method still provides exact confidence intervals for the treatment and carry-over effects, as long as the dropout is independent of the measurement errors. We provide an example for illustration.

Inhibition of human colon cancer cell growth by selective inhibition of cyclooxygenase-2

A considerable amount of evidence collected from several different experimental systems indicates that cyclooxygenase-2 (COX-2) may play a role in colorectal tumorigenesis. Large epidemiologic studies have shown a 40-50% reduction in mortality from colorectal cancer in persons taking aspirin or other nonsteroidal antiinflammatory drugs on a regular basis. One property shared by all of these drugs is their ability to inhibit COX, a key enzyme in the conversion of arachidonic acid to prostaglandins. Two isoforms of COX have been characterized, COX-1 and COX-2. COX-2 is expressed at high levels in intestinal tumors in humans and rodents. In this study, we selected two transformed human colon cancer cell lines for studies on the role of COX-2 in intestinal tumorigenesis. We evaluated HCA-7 cells which express high levels of COX-2 protein constitutively and HCT-116 cells which lack COX-2 protein. Treatment of nude mice implanted with HCA-7 cells with a selective COX-2 inhibitor (SC-58125), reduced tumor formation by 85-90%. SC-58125 also inhibited colony formation of cultured HCA-7 cells. Conversely, SC-58125 had no effect on HCT-116 implants in nude mice or colony formation in culture. Here we provide evidence that there may be a direct link between inhibition of intestinal cancer growth and selective inhibition of the COX-2 pathway.

N-(4-hydroxyphenyl)retinamide induces apoptosis in T lymphoma and T lymphoblastoid leukemia cells

We demonstrate that N-(4-hydroxyphenyl)-all-trans-retinamide (4-HPR), a synthetic retinoic acid (RA) derivative, is a potent and selective inducer of apoptosis in malignant T lymphoid cells, but has little effect on normal lymphoid cells of the thymus or spleen. 4-HPR and its stereoisomer, 9-cis-4-HPR, are 50 to > 150 times more potent than 7 other retinoids in killing CEM-C7 human T lymphoblastoid leukemia cells and P1798-C7 murine T lymphoma cells. 4-HPR's apoptotic action requires the intact molecule bearing both the retinoid moiety and the hydroxyphenol ring; 4-HPR remains unmetabolized after uptake into CEM-C7 and P1798-C7 cells for up to 24 hours. We also show that glucocorticoid (GC)-resistant variants are equally susceptible to 4-HPR as are GC-sensitive cells. Thus, 4-HPR may be potentially important as a new chemotherapeutic drug for use as alternative to, or in combination with, conventional drugs for treating lymphoid malignancies.

Cyclooxygenase-2 induction and transforming growth factor beta growth inhibition in rat intestinal epithelial cells

Rat intestinal epithelial cells (RIE-1) permanently transfected with the prostaglandin endoperoxide synthase 2 (also referred to as cyclooxygenase-2; COX-2) gene exhibit decreased cyclin D1 levels, decreased cdk4-associated kinase activity, and delayed G1 cell cycle progression, which represents a phenotype similar to that which follows transforming growth factor beta (TGF-beta) treatment. In the current study, we have found that addition of TGF-beta 1 to the parental RIE-1 cells (designated RIE-P) caused a rapid induction of COX-2 mRNA and protein. COX-2 protein levels progressively increased and reached peak levels 6 h after TGF-beta 1 addition. Cyclin D1 was decreased by 74% at 6 h and was undetectable 24 h after addition of TGF-beta 1. In RIE cells transfected with the COX-2 antisense expression vector (RIE-AS cells), TGF-beta 1 induction of COX-2 protein was reduced greater than 90%. Addition of TGF-beta 1 did not reduce the abundant cyclin D1 protein expression in the RIE-AS cells, unlike the effect in RIE-P cells. TGF-beta 1 treatment reduced peak [3H]thymidine incorporation by 60% and delayed G1/S-phase transition by at least 4 h in the RIE-P cells. In contrast, S-phase entry occurred at 16 h in RIE-AS cells and was not altered by TGF-beta 1 treatment. Restoration of cyclin D1 expression by transfection of the cyclin D1 cDNA under transcriptional control of the cytomegalovirus promoter/enhancer in the COX-2-overexpressing (RIE-S) cells decreased the time required for S-phase entry by at least 4 h and increased the peak level of [3H]thymidine incorporation. Taken together, the results demonstrate that TGF-beta 1 strongly induces COX-2 at both the mRNA and protein levels and suggest that this induction of COX-2 is involved in the down-regulation of cyclin D1 and inhibition of cell growth caused by TGF-beta 1 in rat intestinal epithelial cells.

Five complete genomes of JC virus type 3 from Africans and African Americans

The central demyelinating disease progressive multifocal leukoencephalopathy (PML) is caused by the human polyomavirus JC virus (JCV). JCV evolved as geographically based genotypes of which Type 3 is an African variant first characterized in HIV-1 positive patients from Tanzania. This study reports the complete sequence of five JCV Type 3 strains. The entire JCV genome was PCR amplified from urine specimens of three African and two African-American individuals. The African consensus sequence was compared to the Type 1 and Type 2 prototype strains, JCV (Mad-1) and JCV(GS/B), respectively. Type 3 differed in 2.2% of its coding region genome from JCV (Mad-1) and in 1.3% from JCV(GS/B). Within the coding region the sequence variation among the three types was higher in the capsid protein VP1 and in the regulatory protein large T antigen than in the agnoprotein or in VP2/3. Notable Type 3-specific changes were located at sites adjacent to the zinc finger motif and near the major donor and acceptor splice junctions of large T antigen. Four of the five urinary Type 3 strains had an unrearranged, archetypal regulatory region. African strain #309 showed a 10-bp deletion at a location similar to that previously described for #307 from Tanzania. The African-American Type 3 strain #312 was closely related to the African consensus sequence. The complete genome of a urinary JCV strain from another African-American male, previously reported as a possible Type 5, showed a sequence difference of only 0.52% from the Tanzanian consensus and has been reclassified as a subtype of Type 3.

Tetrasomy 8 detected by interphase cytogenetics in a child with acute lymphocytic leukemia

Tetrasomy 8 is a rare clonal anomaly in human acute leukemia. Here we present a case of a 7-year-old boy with acute lymphoblastic leukemia (ALL) displaying a tetrasomy 8 clone that could not be detected by conventional cytogenetics. In this study, bone marrow and peripheral blood cells were collected at five different diagnostic stages and analyzed by double targeted fluorescence in situ hybridization (FISH) with centromeric DNA probes for chromosomes 7, 8, 9, and 12. FISH analysis revealed a significant increase in tetrasomy 8 frequency, but not in other chromosomes examined. A smaller increase in trisomy 8 was also detected. At one stage over 60% of the cells were hyperdiploid with 40% being tetrasomic. The size of the tetrasomic clone changed during the course of the disease. The hyperdiploid frequencies of chromosome 8 detected by interphase FISH analysis in bone marrow and peripheral blood were similar. Our findings indicate the utility of FISH analysis in cytogenetic monitoring of leukemia patients and further show that tetrasomy 8 may play a specific role in a subtype of ALL.

[Study of immunoregulation by interleukin-1 receptor antagonist in NZB/W F1 mice]

OBJECTIVE

It is known that the development of systemic lupus erythematosus (SLE) is associated with the highly activated B cells. Interleukin-1 (IL-1) can obviously promote the proliferation and secretive activity of B cells. Moreover, interleukin-1 receptor antagonist (IL-1ra) can block the effect of IL-1 by specifically combining with IL-1 receptor, we, therefore studied the immunoregulative action of IL-1ra in lupus-like NzB/w F1 mice to detect any possible way to prevent lupus nephritis.

METHODS

12 femal NZB/W F1 mice of 13 weeks (Weight: 30-35 g) were divided randomly into 2 groups. Each mouse in the treated group was intraperitoneally injected with IL-1ra once per 2 weeks for 3 times by the dosage of 100 micrograms (0.1 ml) per time, while in the control group injected with 0.1 ml normal saline. All the mice were killed at the age of 9 months and the immunologic function was detected.

RESULTS

This dosage could not prevent absolutely the development of lupus nephritis, but the renal damage was alleviated and the urine protein decreased. Moreover, it could improve the immunofunction by significantly reducing the levels of serum IL-1 alpha and obviously increasing the activities of NK cells and IL-2 induced by ConA in mononuclear cells of spleen. There was no significant difference on the levels of serum IL-6 and TNF-alpha between the treated group and control group.

CONCLUSION

IL-1ra has certain regulatory effect on the immunologic function of lupus-like NZB/W F1 mice.

[The molecular cloning and sequencing of the cobra serum antitoxic protein gene]

In the previous study the authors found at least one peptide of 39 amino acid residues of several purified tryptic-fragments of the cobra serum antitoxic protein (CSAP), whose sequence had shown certain correlation with the rat serum albumin. For further clarification of the toxin-binding activity of CSAP in relation with its corresponding structure, the cDNA gene library of cobra liver cells was established and DNA primers were designed according to the known amino acid sequences of the tryptic peptides of CSAP. The specific probes were prepared and the specific clone was screened out from the library by PCR. Finally, the CSAP cDNA was sequenced from its sub-clones. Then the complete amino acid sequence of CSAP was elucidated. It is a polypeptide chain of 614 amino acid residues with a molecular size of 69.8 KDa. In comparing the whole sequence of CSAP, especially its signal peptide, with mammalian serum albumins, the authors have come to realize that CSAP is just the cobra serum albumin (CSA).

Delayed-type hypersensitivity testing in Tanzanian adults with HIV infection

Delayed-type hypersensitivity (DTH) testing and total lymphocyte counts as measures of cell-mediated immune function were assessed for medical patients in Dar es Salaam, Tanzania. DTH testing was performed with the Multitest CMI device which simultaneously administers seven antigens. Of 201 patients completing DTH testing, 90 were HIV seropositive. Anergy occurred more frequently among HIV-seropositive patients (39 of 90) as compared with HIV-seronegative patients (17 of 111). DTH skin test reactivity, measured by anergy, the number of positive antigens, and the combined DTH response induration, was significantly related to the clinical stage of HIV disease. Median total lymphocyte counts were significantly lower in HIV-seropositive patients than in HIV-seronegative patients (1,130 vs. 1,680 lymphocytes x 10(6)/L). Total lymphocyte counts decreased with increasing severity of HIV disease. In multivariable analysis, the number of positive antigens in DTH testing and lymphopenia significantly predicted HIV infection. The findings suggest that DTH testing and total lymphocyte counts may be useful, inexpensive tests of immune function in African patients with HIV disease.

HIV-1 proviral DNA sequences of env gp41 PCR amplificates from Tanzania

The polymerase chain reaction (PCR) and direct DNA sequencing were used to detect and characterize selected regions of the HIV-1 proviral genome in whole blood samples from Tanzania. Specific PCR amplification products were obtained in gag and/or env (gp41) regions from 15 of the 19 HIV-1 seropositive samples investigated. Env regions from 12 different amplificates were further characterized using the dideoxy sequencing method. Preliminary results indicate that, despite scattered nucleotide mismatches, HIV-1 gp41 amino acid sequences from Tanzania conform to the 1990 Los Alamos African consensus sequence and resemble the HIV-1 subtype A or D consensus sequences in the characterized regions.

CIF, an essential cofactor for TFIID-dependent initiator function

The core promoters for mammalian protein-coding genes often contain a TATA box, an initiator (Inr) element, or both of these control elements. The TFIID complex is essential both for TATA activity and for the activity of a common class of Inr elements characterized by an approximate consensus sequence PyPyA+1NT/APyPy. Although the complete set of proteins required for basal TATA-mediated transcription has been established, the requirements for TFIID-dependent Inr activity remain undefined. In this study we set out to reconstitute Inr activity with purified and recombinant general transcription factors. For this analysis, Inr activity was measured as the ability of an Inr to enhance the strength of a core promoter containing an upstream TATA box. Inr activity was not detected in reactions containing TFIIB, RAP30, RAP74, RNA polymerase II, and either TBP or TFIID, even though these factors were sufficient for TATA-mediated transcription from supercoiled templates. By use of a complementation assay, a factor that imparts Inr activity was identified. This factor, named CIF, stimulated Inr activity in reactions containing the TFIID complex, but activity was not detected with TBP. Further characterization of CIF suggested that it contains multiple components. Functional and immunological experiments demonstrated that one of the CIF components is the mammalian homolog of Drosophila TAF(II)150, which is not tightly associated with mammalian TFIID. These results reveal significant differences in the factor requirements for basal TATA and Inr activity. Further elucidation of these differences is likely to explain the need for the core promoter heterogeneity found within protein-coding genes.