Nuclear death receptor TRAIL-R2 inhibits maturation of let-7 and promotes proliferation of pancreatic and other tumor cells

BACKGROUND & AIMS

Tumor necrosis factor-related apoptosis inducing ligand (TRAIL-R1) (TNFRSF10A) and TRAIL-R2 (TNFRSF10B) on the plasma membrane bind ligands that activate apoptotic and other signaling pathways. Cancer cells also might have TRAIL-R2 in the cytoplasm or nucleus, although little is known about its activities in these locations. We investigated the functions of nuclear TRAIL-R2 in cancer cell lines.

METHODS

Proteins that interact with TRAIL-R2 initially were identified in pancreatic cancer cells by immunoprecipitation, mass spectrometry, and immunofluorescence analyses. Findings were validated in colon, renal, lung, and breast cancer cells. Functions of TRAIL-R2 were determined from small interfering RNA knockdown, real-time polymerase chain reaction, Drosha-activity, microRNA array, proliferation, differentiation, and immunoblot experiments. We assessed the effects of TRAIL-R2 overexpression or knockdown in human pancreatic ductal adenocarcinoma (PDAC) cells and their ability to form tumors in mice. We also analyzed levels of TRAIL-R2 in sections of PDACs and non-neoplastic peritumoral ducts from patients.

RESULTS

TRAIL-R2 was found to interact with the core microprocessor components Drosha and DGCR8 and the associated regulatory proteins p68, hnRNPA1, NF45, and NF90 in nuclei of PDAC and other tumor cells. Knockdown of TRAIL-R2 increased Drosha-mediated processing of the let-7 microRNA precursor primary let-7 (resulting in increased levels of mature let-7), reduced levels of the let-7 targets (LIN28B and HMGA2), and inhibited cell proliferation. PDAC tissues from patients had higher levels of nuclear TRAIL-R2 than non-neoplastic pancreatic tissue, which correlated with increased nuclear levels of HMGA2 and poor outcomes. Knockdown of TRAIL-R2 in PDAC cells slowed their growth as orthotopic tumors in mice. Reduced nuclear levels of TRAIL-R2 in cultured pancreatic epithelial cells promoted their differentiation.

CONCLUSIONS

Nuclear TRAIL-R2 inhibits maturation of the microRNA let-7 in pancreatic cancer cell lines and increases their proliferation. Pancreatic tumor samples have increased levels of nuclear TRAIL-R2, which correlate with poor outcome of patients. These findings indicate that in the nucleus, death receptors can function as tumor promoters and might be therapeutic targets.

Catecholamines reduce dose-dependent oedema formation and inflammatory reaction in an isolated rat lung model

AIM

Since we detected that donor dopamine pre-treatment ameliorates lung function after hypothermia and ischaemia/reperfusion in an isolated rat lung model we studied, whether other catecholamines have beneficial effects on lungs.

MATERIALS AND METHODS

Rats were treated with noradrenaline, adrenaline or dobutamine in different doses. Thereafter lungs were explanted, flushed with Perfadex® solution and stored at 4°C for different time periods. Oedema production was measured and inflammatory mediators were analysed after reperfusion and ventilation.

RESULTS

Low-dose noradrenaline or dobutamine did not reduce tissue oedema after eight hours of hypothermia, whereas higher doses significantly reduced oedema formation. Low-dose catecholamines did not prevent the inflammatory response, whereas higher doses of beta-receptor-stimulating catecholamines significantly blunted inflammatory reaction.

CONCLUSION

This study demonstrates that adrenergic-receptor-stimulating catecholamines have a protective dose-dependent effect on lungs after hypothermia and ischaemia/reperfusion. Although noradrenaline and dobutamine have similar dose-dependent organ-protective effects to dopamine, they have more side-effects.

[Skin barrier defects in atopic dermatitis: new treatments?]

Atopic dermatitis (AD) is a chronic inflammatory skin disorder and the most frequent skin disease in children. Skin barrier defects play a crucial role in its pathogenesis. 50% of patients suffering from AD present mutations in the filaggrin gene, coding for a key protein of the upper layer of the skin. However these mutations alone are not sufficient for disease development, suggesting that environmental factors are also of great importance in the genesis of AD. In particular skin infections frequently provoke clinical exacerbations in patients suffering from AD. New insights into skin barrier dysfunctions have facilitated the development of drugs targeting the sustainable restitution of the skin's physiologic function. These agents could modify the pharmacological approach of AD treatments in the future.

[Antiseptic anaphylaxis]

Antiseptics are widely used in medical practice. Their cutaneous secondary effects such as allergic contact dermatitis are well known. However, anaphylactic reactions are less. The scope of this article is to describe antiseptics currently used which cause immediate hypersensitivity reactions. Finally, the diagnostic tools and therapeutic approach will be discussed.

Undergraduate research. Genomics Education Partnership

The Genomics Education Partnership offers an inclusive model for undergraduate research experiences incorporated into the academic year science curriculum, with students pooling their work to contribute to international data bases.

Undergraduate research. Genomics Education Partnership

The Genomics Education Partnership offers an inclusive model for undergraduate research experiences incorporated into the academic year science curriculum, with students pooling their work to contribute to international data bases.

[Chronic urticaria]

Chronic urticaria (CU) is a common disease of unknown origin. Its impact on the quality of life is significant. Antibodies to high affinity receptors expressed on mast cells and basophiles (FcepsilonRI) are found in 30% of cases and may be associated with more severe and prolonged symptoms. A wide variety of disorders can be associated with CU. However, in the absence of suggestive signs or symptoms, an extensive workup rarely permits the diagnosis of an underlying pathology. In this case, the work up should be minimal. The newer generation oral anti-histamines represent the first line treatment. In the refractory cases, other drugs may be considered but few controlled studies support their use.

[Pratical aspects of anti-Ige therapy in severe allergic asthma]

Omalizumab is an anti-IgE monoclonal antibody, available on the swiss market since november 2006, with the indication as add on therapy for the treatment of poorly controlled severe persistent allergic asthma. These severe asthmatics consume a great share of the resources dedicated to asthma. Many randomised controlled studies have demonstrated the efficacy of omalizumab in reducing exacerbation and requirement of inhaled corticosteroids and in improving quality of life. Omalizumab is reimbursed in Switzerland for adults and children over 12 years of age, with objective markers of atopy and total IgE ranging between 30 et 700 UI/ml. Only allergists and respiratory physician can prescribe this drug in Switzerland. This reyiew focuses on the rationale, indications and practical use of anti-IgE therapy.

Cell-specific enhancement of liposomal transfection by steroids in steroid receptor expressing cells

The DNA transfer efficiency in liposomal versus viral transfection is very low, mainly due to an insufficient nuclear transport of the delivered DNA after its endocytotic uptake to the cell. Ligand activation of intracellular steroid receptors and their subsequent mobilization to the nucleus could result in a co-transport of DNA to the nucleus. The augmentation of nuclear transport of DNA after steroid addition might cause enhanced transfection efficiency. We used cell lines from gynecologic malignoma expressing steroid receptors, such as T47D and Mcf-7 breast cancer cell lines, as well as receptor-negative cell lines, such as Hec1A from endometrium carcinoma or the breast cancer cell line MDA-MB-231. The cells were transfected by the liposomal transfection agent Dotap with the gene for firefly-luciferase as a reporter gene and transfection efficiencies were determined in the luciferase assay. We compared the effect of the addition of cholesterol and steroids in different cell lines on the transfection efficiency. The addition of cholesterol to transfection agents led to an enhancement of the luciferase activity in all cell lines. Steroids enhanced the transfection efficiency only in receptor-positive cell lines. The transfection efficiencies of HEC-1A or MDA-MB-231 cells were not enhanced by steroids. A progesterone preincubation of receptor-positive T47D cells resulted in a decrease of progesterone receptors and afterwards the progesterone enhanced transfection was dramatically diminished. We presume that the transfection enhancement by steroids is dependent on increased nuclear import of the delivered DNA only in the presence of steroid receptors. Steroid enhancement of transfection is different from the benefit of cholesterol for transfection that acts on general cellular properties or the transfection complex as such. Liposomal transfection in combination with steroids might be useful for a cell-specific enhancement of gene transfer for example in gynecological malignoma where subgroups are expressing high levels of steroid receptors.

[Lake Geneva Region guidelines on management of adult asthma]

Asthma is a major cause of chronic morbidity throughout the world. In Switzerland, 6.9% of the adult population is suffering from asthma. The standards of treatment are unfortunately not met in most western countries, as well as in Switzerland. We put forward a complete guideline on management of adult asthma, inspired from GINA and BTS guidelines, and adapted to the specific needs of general practitioners working in french part of Switzerland. This guideline reflects a consensus between allergy, lung and emergency specialists, working in the 2 university hospitals of the Lake Geneva Region (HUG and CHUV).

Ragweed (Ambrosia) progression and its health risks: will Switzerland resist this invasion?

The purpose of this article is to alert physicians for the environmental and health threats of Ambrosia artemisiifolia (common ragweed) in Switzerland. Switzerland borders several heavily ragweed colonised areas. Up to 12% of the population suffers from allergies (hay fever, asthma) to ragweed pollen in these areas. Switzerland is beginning to be invaded by this plant. Currently, the ragweed pollen counts are still low but can reach local peaks that induce symptoms in allergic individuals. Ragweed allergy, however, is still rare in Switzerland. Because the amount of ragweed pollen was increasing in the last few years, identification and surveillance of ragweed plant foci was started. Colonisation is currently systematically monitored in Geneva and southern Tessin. Major accumulation of ragweed foci have been detected in the canton of Geneva, the western shore of the lake of Geneva belonging to the canton of Vaud, and in the southern part of the canton of Tessin, aside from minor foci registered all over Switzerland. The routes of ragweed invasion are presented and discussed. Current measures of ragweed containment and needs for the future are presented. The urge for these measures at an early stage of ragweed spread is underlined by the impracticability of eradication in highly colonised areas. The costs of preventing ragweed spread in Switzerland are likely to be several magnitudes lower than the treatment of a significant percentage of the Swiss population for ragweed pollen allergy. Because areas can change from low to heavy ragweed colonisation within a few years, the current window of opportunity to prevent further colonisation by ragweed should not be missed.

Ragweed (Ambrosia) progression and its health risks: will Switzerland resist this invasion?

The purpose of this article is to alert physicians for the environmental and health threats of Ambrosia artemisiifolia (common ragweed) in Switzerland. Switzerland borders several heavily ragweed colonised areas. Up to 12% of the population suffers from allergies (hay fever, asthma) to ragweed pollen in these areas. Switzerland is beginning to be invaded by this plant. Currently, the ragweed pollen counts are still low but can reach local peaks that induce symptoms in allergic individuals. Ragweed allergy, however, is still rare in Switzerland. Because the amount of ragweed pollen was increasing in the last few years, identification and surveillance of ragweed plant foci was started. Colonisation is currently systematically monitored in Geneva and southern Tessin. Major accumulation of ragweed foci have been detected in the canton of Geneva, the western shore of the lake of Geneva belonging to the canton of Vaud, and in the southern part of the canton of Tessin, aside from minor foci registered all over Switzerland. The routes of ragweed invasion are presented and discussed. Current measures of ragweed containment and needs for the future are presented. The urge for these measures at an early stage of ragweed spread is underlined by the impracticability of eradication in highly colonised areas. The costs of preventing ragweed spread in Switzerland are likely to be several magnitudes lower than the treatment of a significant percentage of the Swiss population for ragweed pollen allergy. Because areas can change from low to heavy ragweed colonisation within a few years, the current window of opportunity to prevent further colonisation by ragweed should not be missed.

[Anaphylaxis: initial management]

Anaphylaxis is an immediate systemic reaction caused by an external agent. Its initial management depends on the severity of the reaction. In case of benign to moderate reaction, anti-histamine and steroid treatment are sufficient to control the process, and management is ambulatory. A severe reaction (hypotension, dyspnea) can be life threatening and adrenalin administration by the intramuscular route is indicated. In this case, it is advocated to observe the evolution for 24 hours in the hospital and the patient should be prescribed adrenaline auto-injectors. It is recommended that individuals who have experienced anaphylaxis should receive consultation from an allergist regarding diagnosis, prevention and treatment.

Additive effect of steroids and cholesterol on the liposomal transfection of the breast cancer cell line T-47D

The efficiency of gene transfer is many times higher in viral than in liposomal transfection. One reason for this is an insufficient intracellular transport of the exogenous DNA into the nucleus in lipofection. Using liposomal transfection techniques for gene therapy is safer than viral approaches, so it would be of great importance to find solutions for their enhancement. We found a 4.51-fold increase in liposomal transfection of T-47D breast cancer cells by the addition of progesterone and a 2.81-fold increase by the addition of cholesterol. The transfection efficiency was measured as the activity of the delivered reporter gene luciferase. The addition of progesterone and cholesterol in combination led to a further enhancement of the transfection efficiency up to 13.72-fold. This additive effect could also be seen when we combined cholesterol with other steroids, but not by the combination of different steroids. All of these steroids alone had also the potential to increase liposomal transfection. Therefore we suggest that steroids and cholesterol enhance liposomal transfection by different mechanisms. Both substances have been shown to shift the exogenous DNA from the cytosol to the nucleus. Steroids normally act through intracellular steroid receptors, which migrate into the nucleus upon activation. The transfected DNA might be co-transported to the nucleus together with the migration of the activated steroid receptors. Even if cholesterol causes also an intracellular shift of DNA to the nucleus, its impact on the fluidity of cellular membranes or on the stability of lipoplexes in serum containing media could be mainly responsible for its effect. If the steroid enhanced liposomal transfection is dependent on the presence of steroid receptors, a specifically-enhanced gene delivery for a subgroup of gynecological tumours expressing high levels of steroid receptors could be possible.

[Enhanced liposomal transfection through the application of sex steroids in gynecological cancer cells]

OBJECTIVE

Liposomal transfection in gene therapeutic application against gynecological malignoma does not reach satisfying efficacy. A desirable goal would be the specific intensification of transfection in these kind of cells. Steroids have successfully been used in other systems to increase liposomal transfection and hopefully there might be a specific impact of sexual steroids in cells from high sex steroid receptor expressing malignoma, like some mamma- and endometrium cancer.

MATERIAL AND METHODS

The mamma carcinoma cell line T-47D was transfected with the transfection agent DOTAP and cyclodextrin solubilized steroids and cholesterol were co-applied. The efficiency of transfection was followed by luciferase activity resulting from the transfected reporter gene.

RESULTS

Like cholesterol, which is already established as transfection co-agent, also the steroids progesterone, estrogen, testosterone and hydrocortisone provoked a clear increase in transfection efficiency shown in a dose dependent manner.

CONCLUSIONS

These results indicate the usefulness of steroids as additives for liposomal transfection procedures in gene therapeutic application. As sexual steroid receptors migrate into the nucleus of a cell after binding its specific ligand a targeted enhancement of transfection is supposable in malignoma overexpressing steroid receptors. There is evidence that plasmid DNA can be co-transported with nuclear proteins into the nucleus.

Transcriptional regulation of tumor necrosis factor-alpha in keratinocytes mediated by interleukin-1beta and tumor necrosis factor-alpha

Irritant contact dermatitis (ICD) is an inflammatory skin reaction in which cytokines are thought to play a crucial role. In particular, tumor necrosis factor-alpha (TNF-alpha) has been implicated in the mechanism of this reaction. We report that interleukin-1beta (IL-1beta) that has been reported up-regulated in many inflammatory skin conditions is capable of increasing TNF-alpha mRNA and protein expression in murine keratinocytes. Furthermore, we show that TNF-alpha is capable of up-regulating itself in keratinocytes most likely in an autocrine manner. The signalling mechanisms involved in both IL-1beta- and TNF-alpha-mediated regulation of TNF-alpha are critically dependent upon protein kinase C (PKC), as demonstrated by blocking studies using protein kinase inhibitors. Furthermore, the increase in TNF-alpha mRNA expression seen after stimulation with rTNF-alpha and rIL-1beta involved increased transcription of TNF-alpha mRNA. This was demonstrated in a chloramphenicol acetyltransferase (CAT) assay using a CAT-construct containing the full-length TNF-alpha promoter. These observations support the notion of keratinocytes functioning as an amplifier of pro-inflammatory cytokine generation in the epidermis during ICD and other inflammatory skin conditions.

In vivo functional proteomics: mammalian genome annotation using CD-tagging

A self-inactivating CD-tagging retroviral vector was used to introduce epitope and GFP tags into genes and proteins in NIH 3T3 cells. Several hundred cell clones, each expressing GFP fluorescence in a distinctive pattern, were isolated. Molecular analysis showed that a wide variety of genes and proteins, some known and some newly discovered, had been tagged. The analysis also revealed that, in the great majority of instances, the abundance and cellular location of the tagged protein mirrored that of its untagged counterpart. This approach provides a systematic means for the functional annotation of mammalian genomes and proteomes in living cells.

Influence of occupational exposure to latex on the prevalence of sensitization and allergy to latex in a Swiss hospital

BACKGROUND

Replacement of powdered latex gloves has been recommended in order to prevent the development of latex allergy in health care workers. The conclusion that occupational exposure to latex gloves represents a risk factor for latex allergy is mainly based on studies without exposure controls. Atopy is also thought to be a risk factor for the development of latex allergy.

OBJECTIVE

To determine the prevalence of atopy, sensitization to latex, and symptoms following latex exposure in professionally exposed and nonexposed hospital personnel by means of a cross-sectional study.

METHODS

Six hundred randomly sampled individuals working in medicine and surgery departments and in surgery theaters and 300 sex- and age-matched individuals classified as administrative personnel were selected from the employee data base of the Geneva University Hospital. A questionnaire about exposure to latex and symptoms following this exposure was sent to all individuals. Skin prick test reactions and serum IgE to latex as well as standard environmental allergens were determined in both groups.

RESULTS

Respiratory and skin (local) symptoms but not objective tests of latex sensitization (positive skin prick test and specific IgE to latex) were significantly associated with occupational exposure to latex (p < 0.001). Only among atopics subjects was 15 years or more of occupational exposure associated with a significantly higher prevalence of local symptoms than among those who were exposed from 1 to 9 years (odds ratio: 3.2; 95% confidence interval: 1.6-6.5). Atopy was significantly associated with sensitization to latex (odds ratio: 10.3; 95% confidence interval: 4.0-26.6) but not with local symptoms. Tests of latex sensitization were both frequently positive, less frequently negative, resulting in low kappa values.

CONCLUSION

These results support the current preventive health care recommendation to replace powdered latex gloves. In atopics, increasing years of occupational exposure increase the risk of developing latex allergy. In contrast to questionnaires about local symptoms, skin prick tests and specific serum IgE to latex are of limited value in epidemiologic studies of latex allergy.

Progesterone and estradiol enhance lipid mediated transfection of Sk-Br-3 mammalian cancer cells

Cyclodextrin encapsulated beta-estradiol and progesterone were used for enhancement of gene delivery using the breast cancer cell line Sk-Br-3. A non-toxic concentration of cyclodextrin encapsulated sex steroids (50 microM) added to lipid or liposomal transfection led to a 12-fold increase of reporter gene expression (luciferase) with progesterone and an 8-fold increase with estradiol using Lipofectamine Plus mediated transfection. Using the lipid formulation Fugene-6 the results were a 5.5-fold and a 4.5-fold increase respectively. This enhancement could only be observed if the sex steroids were added to the cells before application of the DNA-Fugene complex supporting the evidence that intracellular processes are responsible for the activity of the steroids. The strong differences between progesterone and estradiol in modifying Lipofectamine Plus transfection in Sk-Br-3 cells may to be explained by differences in the distribution of these receptors in the cellular compartments. These results seem to add evidence on the possibility of using sex steroids to increase the efficiency of non-viral vectors for transfection, and may ultimately prove to be relevant to gene therapy in the treatment of breast cancer as well as other solid tumors.

CD34(+) cord blood cells expressing cutaneous lymphocyte-associated antigen are enriched in granulocyte-macrophage progenitors and support extensive amplification of dendritic cell progenitors

OBJECTIVE

We evaluated the frequency of hematopoietic progenitor cells (HPC) in CD34(+)CLA(+) (cutaneous lymphocyte-associated antigen) and CD34(+)CLA(-) cord blood cells, and followed cellular growth and HPC production during cultures in Flt3 ligand, thrombopoietin, and stem cell factor (FTS).

MATERIALS AND METHODS

Immunomagnetic bead-purified CD34(+) cells were sorted into CD34(+)CLA(+) or CD34(+)CLA(-) cells. HPC frequency was assessed by clonal assays in methylcellulose either ex vivo or after, 7, 14, or 21 days of culture with FTS. Dendritic cell (DC) progenitors were evaluated after induction of FTS-amplified cells into DC using secondary cultures containing granulocyte-macrophage colony-stimulating factor and interleukin-4.

RESULTS

Ex vivo, granulocyte-macrophage progenitors were more frequent and erythroid progenitors were less frequent in the CLA(+) fraction. In FTS culture, CD34(+)CLA(+) cells produced greater absolute numbers of CD34(+) cells, granulocyte-macrophage-, erythroid-, and DC (including Langerhans cell-related) progenitors compared to CD34(+)CLA(-) cells. In CD34(+)CLA(+) cultures, CLA(+) cells steadily decreased with time, and CD34(+)CLA(-) cells appeared. In CD34(+)CLA(-) cultures, CLA(+) cells were generated, increased up to day 7, and decreased thereafter. CLA was expressed only on CD34(-) cells in these cultures. Ex vivo, CD34(+)CLA(+) cells could be subdivided further into CD38(low) and CD38(high) cells. Cord blood and growth factor-mobilized CD34(+) cells contained more CLA(+)CD38(low) cells than nonmobilized peripheral blood CD34(+) cells and proliferated more extensively with FTS than the latter cells.

CONCLUSIONS

CD34(+)CLA(+) cells contain a rather immature progenitor capable of high proliferation and extensive amplification of HPC in vitro. This progenitor may be localized in the CD34(+)CLA(+)CD38(low) fraction. In addition, cultures of CD34(+)CLA(+) cells from cord blood produced CD34(+)CLA(-) cells, suggesting that these cells may derive directly from CD34(+)CLA(+) cells in vivo.

Hypothalamic amnesia with spontaneous confabulations: a clinicopathologic study

Previous studies demonstrated that patients producing spontaneous confabulations fail to suppress currently irrelevant memory traces and have anterior limbic lesions, particularly involving the orbitofrontal cortex or the basal forebrain. Here, a woman is described who had sarcoidosis damaging the medial hypothalamus and endocrine dysfunction, and a severe memory failure characterized by spontaneous confabulation, disorientation, and severely impaired free recall with preserved recognition. Isolated hypothalamic damage may produce the same type of memory disorder as orbitofrontal damage.

A critical role for p38 mitogen-activated protein kinase in the maturation of human blood-derived dendritic cells induced by lipopolysaccharide, TNF-alpha, and contact sensitizers

We investigated the involvement of mitogen-activated protein kinases (MAPKs) in the maturation of CD83(-) dendritic cells (DC) derived from human blood monocytes. Maturating agents such as LPS and TNF-alpha induced the phosphorylation of members of the three families of MAPK (extracellular signal-regulated kinase l/2, p46/54 c-Jun N-terminal kinase, and p38 MAPK). SB203580, an inhibitor of the p38 MAPK, but not the extracellular signal-regulated kinase l/2 pathway blocker PD98059, inhibited the up-regulation of CD1a, CD40, CD80, CD86, HLA-DR, and the DC maturation marker CD83 induced by LPS and TNF-alpha. In addition, SB203580 inhibited the enhancement of the allostimulatory capacity and partially prevented the down-regulation of FITC-dextran uptake induced by LPS and TNF-alpha. Likewise, SB203580 partially prevented the up-regulation of IL-1alpha, IL-1beta, IL-lRa, and TNF-alpha mRNA upon stimulation with LPS and TNF-alpha, as well as the release of bioactive TNF-alpha induced by LPS. DC maturation induced by the contact sensitizers 2,4-dinitrofluorobenzene and NiSO(4), as seen by the up-regulation of CD80, CD86, and CD83, was also coupled to the phosphorylation of p38 MAPK, and was inhibited by SB203580. The irritants SDS and benzalkonium chloride that do not induce DC maturation did not trigger p38 MAPK phosphorylation. Together, these data indicate that phosphorylation of p38 MAPK is critical for the maturation of immature DC. These results also suggest that p38 MAPK phosphorylation in DC may become useful for the identification of potential skin contact sensitizers.