Activation of IL-8 via PI3K/Akt-dependent pathway is involved in leptin-mediated epithelial-mesenchymal transition in human breast cancer cells

BACKGROUND INFORMATION

Previous studies have revealed that leptin may be involved in epithelial-mesenchymal transition (EMT), a crucial initiator of cancer progression to facilitate metastatic cascade, increase tumor recurrence, and ultimately cause poor prognosis. However, the underlying mechanism remains unclear. The aim of our present study was to investigate the effect of leptin on EMT of breast cancer cells and the underlying mechanism.

RESULTS

Our data demonstrated that leptin significantly increased the phosphorylation of STAT3, Akt, and ERK1/2, elevated the expression of IL-8, and induced breast cancer cells to undergo EMT. The effect of leptin on IL-8 could visibly abolished by the inhibitor of PI3K LY294002. In addition, leptin-induced EMT of breast cancer cells was blocked by anti-IL-8 antibodies. Examination of the expression of ObR, leptin, IL-8 and EMT-related biomarkers in patient specimens demonstrated that malignant breast carcinoma with lymph node metastases (LNM), which represents poor prognosis, expressed higher levels of ObR, leptin, IL-8 than other types of breast cancer, and displayed more obvious EMT transversion. In vivo xenograft experiment revealed that leptin signally promoted tumor growth and metastasis and increased the expressions of IL-8 and EMT-related biomarkers.

CONCLUSIONS

Our results support that leptin-induced EMT in breast cancer cells requires IL-8 activation via the PI3K/Akt signal pathway.

[The effect of leptin and its mechanisms on the migration and invasion of human breast cancer MCF-7 cells]

OBJECTIVE

To investigate the effect and the relevant molecular mechanisms of leptin on the migration and invasion of human breast cancer MCF-7 cells.

METHODS

The expression of OB-R in MCF-7 cells was measured by RT-PCR and Western blotting. The effects of leptin (100 ng/mL) on the the phosphorylation of a few key cell signaling proteins, p-ERK1/2, p-STAT3, p-AKT in MCF-7 cells were examined by Western blotting. Cell scratch assay and Transwell(TM); assay were utilized to measure the effects of leptin on the migration and invasion capability of MCF-7 cells, respectively. The effects of leptin on the mRNA and protein expression of matrix metalloproteinas 9 (MMP-9) and transforming growth factor β (TGF-β) were measured by RT-PCR and Western blotting.

RESULTS

Both OB-Rb and OB-Rt were expressed in MCF-7 cells. This indicated that leptin may have significant activities in MCF7 cells. Indeed, leptin increased the phosphorylation of p-ERK1/2, p-STAT3, and p-AKT in MCF-7 cells (P < 0.05). Further, leptin promoted migration and invasion of MCF-7 cells, which were attenuated by the JAK/STAT inhibitor AG490 (50 μmol/L), and the PI3K/AKT inhibitor LY294002 (10 μmol/L) (P < 0.05). Similarly, leptin also increased the mRNA and protein expression of MMP-9 and TGF-β, and these effects were blocked by AG490 and LY294002 as well (P < 0.05).

CONCLUSION

Leptin promoted the migration and invasion capabilities of MCF-7 cells. These activities may be achieved by the upregulation of MMP-9 and TGF-β through JAK/STAT and PI3K/AKT signaling pathways.

The brain-derived neurotrophic factor is associated with alcohol dependence-related depression and antidepressant response

Brain-derived neurotrophic factor (BDNF) plays an essential role in neuronal survival, proliferation, and synaptic remodeling and modulates the function of many other neurotransmitters. Additionally, it likely underlies neurodegenerative and psychiatric disorders, including alcohol dependence-related depression (AD-D). Here, we investigated the possible association between three single nucleotide polymorphisms (SNPs) of the BDNF gene (rs13306221, rs6265, rs16917204) and AD-D. Of 548 patients with alcohol dependence (AD), 166 had AD-D and 312 healthy controls. Response to 8-week sertraline treatment was also assessed. The frequency of the A allele of rs6265 (Val66Met) was significantly higher in AD-D patients than in the healthy controls (p=0.009 after Bonferroni correction). The analysis revealed a strong association between the rs6265 genotype distribution and AD-D (p=0.005 after Bonferroni correction), and the A allele of rs6265 was significantly overrepresented in AD-D patients compared to AD without depression (AD-nD) patients (p=0.001 after Bonferroni correction). Additionally, carriers of the A allele of rs6265 responded better to sertraline treatment (p=0.001). Our results suggested a novel association between BDNF rs6265 and AD-D. These findings might lead to earlier detection of AD-D, perhaps providing better tools for clinical care of these patients in the future.

Current good manufacturing practice production of an oncolytic recombinant vesicular stomatitis viral vector for cancer treatment

Vesicular stomatitis virus (VSV) is an oncolytic virus currently being investigated as a promising tool to treat cancer because of its ability to selectively replicate in cancer cells. To enhance the oncolytic property of the nonpathologic laboratory strain of VSV, we generated a recombinant vector [rVSV(MΔ51)-M3] expressing murine gammaherpesvirus M3, a secreted viral chemokine-binding protein that binds to a broad range of mammalian chemokines with high affinity. As previously reported, when rVSV(MΔ51)-M3 was used in an orthotopic model of hepatocellular carcinoma (HCC) in rats, it suppressed inflammatory cell migration to the virus-infected tumor site, which allowed for enhanced intratumoral virus replication leading to increased tumor necrosis and substantially prolonged survival. These encouraging results led to the development of this vector for clinical translation in patients with HCC. However, a scalable current Good Manufacturing Practice (cGMP)-compliant manufacturing process has not been described for this vector. To produce the quantities of high-titer virus required for clinical trials, a process that is amenable to GMP manufacturing and scale-up was developed. We describe here a large-scale (50-liter) vector production process capable of achieving crude titers on the order of 10(9) plaque-forming units (PFU)/ml under cGMP. This process was used to generate a master virus seed stock and a clinical lot of the clinical trial agent under cGMP with an infectious viral titer of approximately 2 × 10(10) PFU/ml (total yield, 1 × 10(13) PFU). The lot has passed all U.S. Food and Drug Administration-mandated release testing and will be used in a phase 1 clinical translational trial in patients with advanced HCC.

Analysis of the effect of copper on the virulence of a pathogenic Edwardsiella tarda strain

AIM

To investigate the effect of copper on the virulence of Edwardsiella tarda.

METHODS AND RESULTS

The pathogenic Edw. tarda strain TX5 was cultured under copper-stressed conditions and examined for any potential alteration in capacities that are associated with pathogenicity. The results showed that compared to untreated TX5, Cu-treated TX5 exhibits reduced planktonic and biofilm growth, an impaired ability to adhere to host mucus, modulation of host immune response, and dissemination in host blood and liver. Consistent with these observations, the overall bacterial virulence of Cu-treated TX5 is significantly attenuated. SDS-PAGE analyses of whole cell protein production showed that Cu-treated TX5 differs from the untreated TX5 in its production of at least one protein. Quantitative real time reverse transcriptase PCR analyses showed that copper treatment decreased the expression of virulence-associated genes encoding components of the type III and type VI secretion systems, the Eth haemolysin system, and the LuxS/AI-2 quorum-sensing system.

CONCLUSIONS

Prolonged exposure to copper has multiple effects on TX5 and results in significant attenuation of bacterial virulence.

SIGNIFICANCE AND IMPACT OF THE STUDY

The results of this study demonstrate that copper treatment has a broad and profound effect on the virulence-associated capacities of TX5, which is exerted at least in part at the transcription level. These findings provide new insights to the antimicrobial mechanism of copper.

XmAb Fc engineered anti-CD19 monoclonal antibodies with enhanced in vitro efficacy against multiple lymphoma cell lines

3021

Background: CD19 is a pan-B cell surface receptor that is expressed from early stages of pre-B cell development through terminal differentiation into plasma cells. It is an attractive immunotherapy target for cancers of lymphoid origin since it is also expressed on the vast majority of Non-Hodgkin Lymphoma (NHL) cells as well as some leukemias. Despite major improvements in response rates and progression free survival the majority of NHL patients will relapse under the current combination chemotherapy with anti-CD20. Thus salvage regimens with new non-cross resistant antibody therapies are warranted. Methods: We employ our XmAb antibody engineering technology to increase the affinity of IgG antibodies for Fc gamma receptors (FcγR), improve the effector function of antibodies, and significantly increases their antitumor potency; we also we humanize and affinity mature such antibodies. Results: The XmAb technology was applied to a humanized anti-CD19 antibody to engineer a variant with significantly enhanced (10- to 100-fold) antibody-dependent cell-mediated cytotoxicity (ADCC). The resulting XmAb CD19 variant was assayed for ADCC against multiple cell lines representative of follicular lymphoma (FL), chronic lymphocytic leukemia (CLL), B-cell acute lymphoblastic leukemia (B-ALL), mantle cell lymphoma (MCL), hairy cell leukemia (HCL), chronic myelogenous leukemia (CML), and Burkitt’s lymphoma (BL). The ADCC activity of the XmAb CD19 was in striking contrast to a wild type IgG1 version of the antibody that mediates little ADCC. Moreover, ADCC potency and efficacy of the anti-CD19 Fc variant antibody were superior to that of rituximab: CLL - 10- and 1.5-fold higher, ALL - 10- and 100-fold higher, and HCL - 6- and 1.2-fold higher, respectively. Further, we observed no correlation between ADCC and antigen expression based on the measured cell surface density of CD19 for these cell lines. Conclusions: The increased affinity for FcγRs exhibited by the anti-CD19 Fc variant antibody overcomes much of the dependence of cytotoxicity on surface antigen density. Our data suggest that the anti-CD19 Fc variant antibody engineered for increased effector function could be a promising next-generation NHL immunotherapeutic.

No significant financial relationships to disclose.

Anti-EpCAM XmAb antibodies with improved cytotoxicity

12506

Background: The epithelial cell adhesion molecule (EpCAM), also known as epithelial protein 2 (EGP-2) or 17–1A antigen, is a trans-membrane protein expressed on the surfaces of most carcinomas, including those of pancreatic, colorectal, prostate, breast, kidney, lung, and ovarian origins. Moderate affinity antibodies (Abs) such as 17–1A (Kd ∼ 10−7 nM) have been safe in humans albeit with limited clinical efficacy. Attempts to improve clinical efficacy by enhancing antigen affinity (Kd ∼ 10−9 nM) have led to serious clinical toxicity, including pancreatitis. These observations raise the question of whether a moderate affinity Ab with enhanced effector function will be both safe and clinically efficacious. Methods: We applied our proprietary XmAb™ technologies to humanize the 17–1A variable domain and engineer a human IgG1 Fc domain to increase affinity for the activating receptor FcγRIIIa. Ab binding to Ep-CAM or to Fc receptors was tested with Biacore and/or AlphaScreen binding assays. In vitro cytotoxic activity against representative cancer cell lines was measured with Antibody Dependent Cell-mediated Cytotoxicity (ADCC) assays, using human PBMC as effector cells. Results: Humanized anti-EpCAM Abs have affinity for EpCAM similar to the parent 17–1A. Affinity for the activating FcγRIIIa was increased 100-fold relative to a control Ab with an IgG1 Fc domain. As expected, these Abs exhibit dramatically enhanced ADCC against multiple cancer cell lines relative to 17–1A and IgG1 control Abs. Despite their moderate affinity for EpCAM, these novel Abs have in vitro cytotoxicity comparable to the high affinity Ab ING-1. CDC activities of these Abs were similar to chimeric 17–1A. Conclusions: We have demonstrated that antibodies with moderate affinity for EpCAM and increased FcγRIIIa affinity exhibit superior cancer cell killing via an ADCC mechanism. The humanized nature and the increased cytotoxicity of anti-EpCAM XmAb™ antibodies make them promising candidates for clinical development of a novel pan-carcinoma Ab that is superior to 17–1A.

[Table: see text]

Enhanced efficacy of a novel controlled release paclitaxel formulation (PACLIMER delivery system) for local-regional therapy of lung cancer tumor nodules in mice

The efficacy of systemic chemotherapy for non-small cell lung cancer (NSCLC) has improved with newer agents. However, the response rates and prolonged survival times achieved by chemotherapy remain modest, and these small gains are obtained at the cost of significant toxicity. In this study, the efficacy of a controlled release formulation of paclitaxel was compared with conventional paclitaxel in animals with human lung cancer xenografts. Paclitaxel (10%) was encapsulated in a proprietary polymer in the form of microspheres (PACLIMER Delivery System). Tumor nodules comprised of two different cell lines (A549 and H1299) were treated by a single i.p. or intratumoral administration of conventionally formulated paclitaxel or a single intratumoral injection of the PACLIMER Delivery System. In vitro testing demonstrated that paclitaxel was released slowly from the microspheres with >80% released after 90 days. Direct comparison of the highest dose for all formulations (24 mg/kg) showed that for nodules comprised of either NSCLC cell line, growth of the PACLIMER Delivery System-treated nodules were inhibited significantly more than the groups treated with conventional paclitaxel or the vehicle controls. Tumor volume doubling times for A549 and H1299 nodules treated with PACLIMER Delivery System were 60 and 35 days, respectively, compared with 10 and 11 days, respectively, in the nodules treated with the conventional paclitaxel by intratumoral administration. We conclude that intratumoral administration of the PACLIMER Delivery System may substantially increase the efficacy of paclitaxel for the therapy of local-regional NSCLC.

Exploring functional redundancy in the immunoglobulin mu heavy-chain gene enhancer

Immunoglobulin (Ig) mu heavy-chain gene enhancer activity is mediated by multiple DNA binding proteins. Mutations of several protein binding sites in the enhancer do not affect enhancer activity significantly. This feature, termed redundancy, is thought to be due to functional compensation of the mutated sites by other elements within the enhancer. In this study, we identified the elements that make the basic helix-loop-helix (bHLH) protein binding sites, muE2 and muE3, redundant. The major compensatory element is a binding site for interferon regulatory factors (IRFs) and not one of several other bHLH protein binding sites. These studies also provide the first evidence for a role of IRF proteins in Ig heavy-chain gene expression. In addition, we reconstituted the activity of a monomeric mu enhancer in nonlymphoid cells and defined the domains of the ETS gene required for function.

Clinical study on acupuncture treatment of stomach carcinoma pain

Clinical observation on 48 cases of stomach carcinoma pain indicated that acupuncture including filiform needle group and point-injection group had better therapeutic effects in treatment of stomach carcinoma pain when patient's mind was concentrated at the site of disease. After treatment for 2 months, the long-term effective rates of analgesia in both the filiform needle group and the point-injection group were similar to that in the western medicine group, all being about 81%. While the long-term markedly effective rates in the two groups were superior to that in the western medicine group. Life quality of the patients in all the groups were improved. The toxic action and side effects caused by chemotherapy were prevented, the high viscous state showed by indexes of blood rheology was improved, and the lowered Cu-Zu-SOD activity in erythrocytes in patients of stomach carcinoma was increased in the filiform needle group and the point-injection group. Based on the results of clinical study, we consider that acupuncture analgesic effect on stomach carcinoma is related to the increase of PLEK, improvement of cellular immune function and the elevation of life quality after acupuncture.

ETS-mediated cooperation between basic helix-loop-helix motifs of the immunoglobulin mu heavy-chain gene enhancer

The muE motifs of the immunoglobulin mu heavy-chain gene enhancer bind ubiquitously expressed proteins of the basic helix-loop-helix (bHLH) family. These elements work together with other, more tissue-restricted elements to produce B-cell-specific enhancer activity by presently undefined combinatorial mechanisms. We found that muE2 contributed to transcription activation in B cells only when the muE3 site was intact, providing the first evidence for functional interactions between bHLH proteins. In vitro assays showed that bHLH zipper proteins binding to muE3 enhanced Ets-1 binding to muA. One of the consequences of this protein-protein interaction was to facilitate binding of a second bHLH protein, E47, to the muE2 site, thereby generating a three-protein-DNA complex. Furthermore, transcriptional synergy between bHLH and bHLH zipper factors also required an intermediate ETS protein, which may bridge the transcription activation domains of the bHLH factors. Our observations define an unusual form of cooperation between bHLH and ETS proteins and suggest mechanisms by which tissue-restricted and ubiquitous factors combine to generate tissue-specific enhancer activity.

A three-protein-DNA complex on a B cell-specific domain of the immunoglobulin mu heavy chain gene enhancer

The lymphoid-specific immunoglobulin mu heavy chain gene intron enhancer (muE) contains multiple binding sites for trans-acting nuclear factors. We have used a combination of in vitro and in vivo assays to reconstruct protein-DNA interactions on a minimal B cell-specific mu enhancer that contains three motifs, muA, muB, and muE3. Using ETS-domain proteins that transactivate the minimal enhancer in non-lymphoid cells, we show that (i) PU.1 binds coordinately to both muA and muB sites in vitro and (ii) in the presence of Ets-1, this factor binds to the muA site and PU.1 to the muB site. Two factors, TFE3 and USF, bind to the muE3 element. When the ETS proteins are present together with muE3 binding proteins, a three-protein-DNA complex is generated. Furthermore, we provide evidence for protein-protein interactions between Ets-1 and PU.1 proteins that bind to muA and muB sites, and between Ets-1 and TFE3 bound to the muA and mu3 sites. We propose that this domain of the mu enhancer is assembled into a nucleoprotein complex that contains two tissue-restricted ETS domain proteins that recognize DNA from the same side of the helix and one ubiquitously expressed bHLH-leucine zipper protein that binds between them, recognizing its site from a different side of the helix.

Morphological characterization of polyanhydride biodegradable implant gliadel during in vitro and in vivo erosion using scanning electron microscopy

PURPOSE

The objectives of the current study are to characterize the distribution of the chemotherapeutic agent carmustine (BCNU) in spray dried polyanhydride microspheres and to describe the morphological changes that occur during the in vitro and in vivo erosion of the polyanhydride implant--GLIADEL, which consists of BCNU distributed in the copolymer matrix of poly(carboxyphenoxy propane:sebacic acid) in a 20:80 molar ratio (p(CPP:SA, 20:80)).

METHODS

Scanning electron microscopy (SEM) was used to visualize the morphological changes of the polymer during the manufacturing process and in vitro and in vivo erosion.

RESULTS

This study revealed that BCNU was homogeneously distributed within spray dried polyanhydride microspheres with no phase separation. The porosity of the wafer fabricated from spray dried polyanhydride microspheres gradually increased during erosion. During the initial period following wafer implantation in the brains of rats, erosion was mainly confined to the surface layer of the wafer with the majority of the wafer remaining intact. The eroding front gradually advanced from the surface to the interior of the wafer in a layerwise fashion, creating pores and connecting channel. Eventually both the interior and exterior of the wafers were eroded and the same porous structure was seen throughout the whole wafer.

CONCLUSIONS

This study provides the first visual observation of the morphological changes of the GLIADEL(R) wafer during erosion of the polyanhydride matrix and release of the drug substance BCNU. The observations in this study support the conclusion that BCNU release from a polyanhydride wafer is controlled both by diffusion of the drug and erosion of the polymer matrix.

Interaction of Ca2(+)-activated K+ channels with refolded charybdotoxins mutated at a central interaction residue

Charybdotoxin is a small peptide blocker of K+ channels, rigidly held in active conformation by three disulfide bonds. The toxin blocks K+ channels by binding to a receptor site located at the external "vestibule", and thus physically occluding the outer opening of the K+ conduction pore. In the blocked complex, K27, a residue on the toxin's molecular surface, projects its epsilon-amino group into the K(+)-selective pore. The results here show that CTX, produced by heterologous expression in E. coli, may be manipulated to place unnatural positively charged residues at position 27. The toxin folds faithfully to its native conformation when the crucial lysine at position 27 is replaced by a cysteine residue, a maneuver that allows specific chemical modification of this side-chain. Replacements of K27 by side-chains slightly shorter or slightly longer than lysine yield active toxins. The toxin variant with ornithine at this position interacts much less strongly with K+ ions in the pore of slowpoke-type Ca2(+)-activated K+ channels than does wild-type toxin. This result argues that the epsilon-amino group of K27 in bound toxin lies only a few ångstroms away from a K+ ion occupying the blocked pore. The peptide folds with high efficiency to form the correct disulfides even in the presence of strong denaturants.

Controlled release of macromolecules from a degradable polyanhydride matrix

Polymeric matrices that slowly release macromolecules may be useful for the controlled delivery of proteins or polymer-drug conjugates for targeted drug delivery. Solid particles of fluorescein and fluorescently-labeled, size-fractionated dextran (4000-150,000 number average molecular weight) were dispersed in degradable polyanhydride matrices composed of a 1:1 copolymer of fatty acid dimers and sebacic acid. The release of macromolecules from the polymer matrix into buffered saline was measured; changes in the polymer during immersion were monitored by infrared spectroscopy, differential scanning calorimetry, and scanning electron microscopy. Although significant hydrolysis of the polymer occurred within the first day, the matrices remained intact and water-soluble tracers were slowly released for several days. During polymer hydrolysis and erosion, micron-sized pores developed throughout the 2 mm thick polymer matrix, permitting water penetration into the matrix and tracer diffusion out of the matrix. The rate of tracer release from the matrix depended on tracer particle size; rates of fluorescein isothiocyanate dextran release were controlled by adjusting the size of particles dispersed in the matrix.

Interleukin-1 receptor antagonist suppresses human chorionic gonadotropin-induced ovulation in the rat

Indirect evidence has implicated the interleukin-1 (IL-1) system in ovulation. Thus, the ability of IL-1 beta to induce ovulation in rat and rabbit perfused ovaries has been demonstrated. In the present study, the involvement of the IL-1 system in ovulation was directly tested in vivo, in the rat model. For this purpose, the natural inhibitor of the IL-1 system, interleukin-1 receptor antagonist (IL-1ra), was administered locally by use of an intrabursal injection route. Twenty-six-day-old Sprague-Dawley rats received injections of eCG (10 IU), followed 56 h later by hCG (15 IU). IL-1ra (75 micrograms/bursa) was administered locally into the periovarian sac, 6 h (n = 5), 2 h (n = 11), and 0 h (n = 5) before hCG administration. Control animals (n = 10) received injections of the same volume (50 microliters) of vehicle (PBS). IL-1ra administered locally into the periovarian sac inhibited ovulation from the treated ovary, reaching 40% inhibition (p < 0.05) when injected 2 h prior to hCG, as compared to the untreated contralateral ovary (6 +/- 1.4 ova vs. 10 +/- 1.8 ova) and PBS-injected control ovaries (6 +/- 1.4 ova vs. 8.2 +/- 0.7). Injection of IL-1ra 6 h before or concomitantly with hCG did not affect the ovulation rate. Internucleosomal DNA fragmentation was evaluated by 3' end-labeling and autoradiography for detecting apoptotic changes. No difference in DNA fragmentation was found between treated and untreated ovaries.(ABSTRACT TRUNCATED AT 250 WORDS)

Covalent coupling of methotrexate to dextran enhances the penetration of cytotoxicity into a tissue-like matrix

For antitumor agents introduced directly into the intracranial space, the extent of penetration into tissue, and hence the effectiveness of therapy, depends on the rate of drug elimination from the tissue. To test the hypothesis that slowly eliminated agents would penetrate further through tissues, methotrexate (MTX)-dextran conjugates were produced by covalently linking MTX to dextran through a short-lived ester bond (MTX-ester-dextran; t1/2 approximately 3 days in buffered saline) and a longer-lived amide bond (MTX-amide-dextran; t1/2 > 20 days in buffered saline). The ability of these agents to kill cells and to penetrate through tissue was evaluated using: (a) human brain tumor (H80) cells in a standard format; (b) H80 cells in a novel three-dimensional format that mimics many characteristics of intracranial tumors; and (c) 9L gliosarcoma in the rat brain. Penetration into three-dimensional tissue-like matrices was performed by suspending H80 cells in agarose gels within a hollow fiber that was permeable to MTX but not dextran and injecting MTX or MTX-dextran conjugates into one end of the fiber. The cytotoxicity of MTX-ester-dextran and MTX-amide-dextran against H80 was equivalent to unmodified MTX (50% inhibitory concentration, approximately 0.01 microgram/ml). When released from a biodegradable polyanhydride polymer matrix, MTX and MTX-dextran conjugates retained their ability to inhibit dihydrofolate reductase activity. When MTX or MTX-dextran was diffused into the three-dimensional tumor cell matrix for 10 days, cytotoxic activity penetrated > 2 cm for MTX-amide-dextran and approximately 1 cm for MTX or MTX-ester-dextran; this enhanced penetration correlated with the stability of the MTX-dextran linkage. Intracranial polymeric delivery of MTX or MTX-amide-dextran to rats with intracranial 9L gliosarcoma produced modest but significant increases in survival; conjugation of MTX to dextran appeared to shift the dose-response curve to a lower dosage.

Interleukin-10 promotes the growth of megakaryocyte, mast cell, and multilineage colonies: analysis with committed progenitors and Thy1loSca1+ stem cells

The growth-promoting activities of interleukin-10 (IL-10) were assessed in hematopoietic colony-forming assays. We found that IL-10 failed to support the clonal growth of normal and lineage-depleted (Lin-) bone marrow (BM) cells. Furthermore, IL-10 neither enhanced nor suppressed colony formation by eosinophil, neutrophil, or macrophage progenitors when combined with a variety of factors. IL-10 stimulated a modest increase in erythropoietin (Epo)-dependent erythroid colonies but had no effect on the burst-promoting activities of IL-3. However, the combination of IL-10 plus IL-3 resulted in the enhanced growth of mast cell progenitors. In addition to its mast cell stimulating activity, IL-10 promoted the growth of megakaryocyte (Mk) and Mk-mixed colonies when combined with Epo or with Epo plus IL-3, IL-6, or IL-11. Comparative studies showed that the megakaryocyte potentiating activity of IL-10 is roughly equivalent to that of IL-6 and IL-11. In experiments using Thy1loSca1+ stem cells, IL-10 was shown to enhance the number of cells initiating IL-3-dependent colony formation. IL-10 also costimulated increased colony formation when used with IL-3 and another factor such as IL-1, IL-6, and granulocyte colony-stimulating factor (G-CSF). Cellular analysis of the resulting colonies indicated that IL-10 increases the formation of multilineage colonies containing erythrocytes, megakaryocytes, and/or mast cells. The ability of IL-10 to cooperatively regulate various stages of hematopoietic development is discussed.

Embryonic implantation in mice is blocked by interleukin-1 receptor antagonist

We have investigated the relevance of interleukin-1 receptor type I (IL-1R tI) in the implantation process in vivo in a murine model. Indirect immunofluorescence experiments demonstrate that IL-1R tI is located in mouse endometrial lumenal epithelium with increased intensity in the periimplantation period, whereas IL-1 beta staining is located in the mouse placenta. PMSG/human CG (hCG)-stimulated and mated 12-week-old B6C3F-1 female mice were randomly allocated to three groups: A, control noninjected; B, buffer-injected animals; and C, animals injected ip with 20 micrograms recombinant human IL-1 receptor antagonist (rhIL-1ra) every 12 h beginning on pregnancy day 3. Injections were continued until day 9, and animals were killed 12 h after the last injection. Pregnancy rates in the three groups were: noninjected, 58.8% (10 of 17); buffer-injected, 73.7% (14 of 19); rhIL-1ra-injected, 6.7% (1 of 15), P = 0.0001155, Fisher exact test. To rule out the possibility that pregnancy failure was due to an embryotoxic effect of rhIL-1ra, 2-cell mouse embryos (n = 276) were flushed from the same group of animals used for in vivo experiments and cultured with increasing concentrations of rhIL-1ra: 0 microgram/ml (n = 91), 1 microgram/ml (n = 36), 50 micrograms/ml (n = 36), 100 micrograms/ml (n = 52), and 200 micrograms/ml (n = 61) rhIL-1ra. The percentages of 2-cell mouse embryos reaching the blastocyst stage after 72 h in culture were 85.7%, 91.6%, 94.4%, 96%, and 85.2%, respectively. We further cultured these blastocysts for 5 days on fibronectin-coated plates with or without 200 micrograms/ml rhIL-1ra. In both groups, hatching, attachment to fibronectin, outgrowth, and migration were documented to be similar. Furthermore, our longitudinal morphological study of embryonic implantation in control and rhIL-1ra-injected mice shows that the blockade of IL-1R tI interferes with the attachment of mouse blastocysts to maternal endometrium in vivo. In summary, we demonstrate that blockade of maternal endometrial IL-1R tI with IL-1ra prevents implantation in the mouse by interfering with embryonic attachment, without adverse effects on blastocyst formation, hatching, fibronectin attachment, outgrowth, and migration in vitro.

Effects of IL-13 on phenotype, cytokine production, and cytotoxic function of human monocytes. Comparison with IL-4 and modulation by IFN-gamma or IL-10

Recently, we described the cloning and expression of a human cDNA which is the homologue to P600, a gene transcribed by mouse Th2 clones. Based on its activities on human monocytes and B cells this gene was designated IL-13. In the present study we investigated the effects of IL-13 alone or in combination with IL-4, IFN-gamma, or IL-10 on human monocytes. IL-13 induced significant changes in the phenotype of monocytes. Like IL-4, it enhanced the expression of CD11b, CD11c, CD18, CD29, CD49e (VLA-5), class II MHC, CD13, and CD23, whereas it decreased the expression of CD64, CD32, CD16, and CD14 in a dose-dependent manner. IL-13 induced up-regulation of class II MHC Ag and its down-regulatory effects on CD64, CD32, and CD16 expression were prevented by IL-10. IFN-gamma could also partially prevent the IL-13-induced down-regulation of CD64, but not that of CD32 and CD16. However, IL-13 strongly inhibited spontaneous and IL-10- or IFN-gamma-induced ADCC activity of human monocytes toward anti-D coated Rh+ erythrocytes, indicating that the cytotoxic activity of monocytes was inhibited. Furthermore, IL-13 inhibited production of IL-1 alpha, IL-1 beta, IL-6, IL-8, IL-10, IL-12 p35, IL-12 p40, macrophage inflammatory protein-1 alpha, granulocyte/macrophage-CSF, granulocyte-CSF, IFN-alpha, and TNF alpha by monocytes activated with LPS. In contrast, IL-13 enhanced the production of IL-1 ra by these cells. Similar results on cytokine production were observed or have been obtained with IL-4. Thus IL-13 shares most of its activities on human monocytes with IL-4, but no additive or synergistic effects of IL-4 and IL-13 on human monocytes were observed, suggesting that these cytokines may share common receptor components. Taken together, these results indicate that IL-13 has anti-inflammatory and important immunoregulatory activities.

Effects of IL-13 on phenotype, cytokine production, and cytotoxic function of human monocytes. Comparison with IL-4 and modulation by IFN-gamma or IL-10

Recently, we described the cloning and expression of a human cDNA which is the homologue to P600, a gene transcribed by mouse Th2 clones. Based on its activities on human monocytes and B cells this gene was designated IL-13. In the present study we investigated the effects of IL-13 alone or in combination with IL-4, IFN-gamma, or IL-10 on human monocytes. IL-13 induced significant changes in the phenotype of monocytes. Like IL-4, it enhanced the expression of CD11b, CD11c, CD18, CD29, CD49e (VLA-5), class II MHC, CD13, and CD23, whereas it decreased the expression of CD64, CD32, CD16, and CD14 in a dose-dependent manner. IL-13 induced up-regulation of class II MHC Ag and its down-regulatory effects on CD64, CD32, and CD16 expression were prevented by IL-10. IFN-gamma could also partially prevent the IL-13-induced down-regulation of CD64, but not that of CD32 and CD16. However, IL-13 strongly inhibited spontaneous and IL-10- or IFN-gamma-induced ADCC activity of human monocytes toward anti-D coated Rh+ erythrocytes, indicating that the cytotoxic activity of monocytes was inhibited. Furthermore, IL-13 inhibited production of IL-1 alpha, IL-1 beta, IL-6, IL-8, IL-10, IL-12 p35, IL-12 p40, macrophage inflammatory protein-1 alpha, granulocyte/macrophage-CSF, granulocyte-CSF, IFN-alpha, and TNF alpha by monocytes activated with LPS. In contrast, IL-13 enhanced the production of IL-1 ra by these cells. Similar results on cytokine production were observed or have been obtained with IL-4. Thus IL-13 shares most of its activities on human monocytes with IL-4, but no additive or synergistic effects of IL-4 and IL-13 on human monocytes were observed, suggesting that these cytokines may share common receptor components. Taken together, these results indicate that IL-13 has anti-inflammatory and important immunoregulatory activities.

Interleukin 13, a T-cell-derived cytokine that regulates human monocyte and B-cell function

We have isolated the human cDNA homologue of a mouse helper T-cell-specific cDNA sequence, called P600, from an activated human T-cell cDNA library. The human cDNA encodes a secreted, mainly unglycosylated, protein with a relative molecular mass of approximately 10,000. We show that the human and mouse proteins cause extensive morphological changes to human monocytes with an associated up-regulation of major histocompatibility complex class II antigens and the low-affinity receptor for immunoglobulin E (Fc epsilon RII or CD23). In addition, they stimulate proliferation of human B cells that have been activated by anti-IgM antibodies or by anti-CD40 monoclonal antibodies presented by a mouse Ltk- cell line transfected with CDw32. Furthermore, the human protein induced considerable levels of IgM and IgG, but no IgA production, in cultures in which highly purified human surface IgD+ or total B cells were cocultured with an activated CD4+ T-cell clone. Based on these findings, we propose that this immunoregulatory protein be designated interleukin 13.

Dextran retention in the rat brain following release from a polymer implant

Intracranial controlled release polymers may improve drug administration to the brain, where therapy is frequently limited due to the low permeability of brain capillaries to therapeutic agents. On the basis of drug transport and elimination rates, we proposed that high molecular weight, water-soluble molecules would be retained in the brain space following release from an intracranial implant. To test this hypothesis, solid particles of different molecular weight fractions of fluorescein isothiocyanate labeled dextran (FITC-dextran; 4 x 10(3) Da (4 kDa) < weight-averaged molecular weight (Mw) < 150 kDa) or fluorescein were uniformly dispersed in matrices of a polyanhydride copolymer synthesized from a fatty acid dimer and sebacic acid in a 50:50 ratio, P(FAD:SA). When incubated in buffered saline, FITC-dextran fractions of 70 kDa Mw were released from the polymer within 48 h; 4 kDa Mw FITC-dextran and fluorescein were released more slowly. Following implantation of P(FAD:SA) matrices containing either 70 kDa Mw FITC-dextran, 4 kDa Mw FITC-dextran, or fluorescein into the brains of normal rats, fluorescent tracers were continuously released into the brain tissue for 30 days. Tracer concentrations within the brain were significantly higher for large molecular weight tracers (70 kDa Mw FITC-dextran >> 4 kDa Mw FITC-dextran > fluorescein). The rate of elimination, kapp, of each tracer from the brain was determined by comparing experimental data with a model describing tracer diffusion/elimination in the brain extracellular space; kapp decreased with increasing molecular weight (fluorescein > 4 kDa Mw FITC-dextran > 70 kDa Mw FITC-dextran).