Effects of Renal Denervation vs Sham in Resistant Hypertension After Medication Escalation: Prespecified Analysis at 6 Months of the RADIANCE-HTN TRIO Randomized Clinical Trial

Importance

Although early trials of endovascular renal denervation (RDN) for patients with resistant hypertension (RHTN) reported inconsistent results, ultrasound RDN (uRDN) was found to decrease blood pressure (BP) vs sham at 2 months in patients with RHTN taking stable background medications in the Study of the ReCor Medical Paradise System in Clinical Hypertension (RADIANCE-HTN TRIO) trial.

Objectives

To report the prespecified analysis of the persistence of the BP effects and safety of uRDN vs sham at 6 months in conjunction with escalating antihypertensive medications.

Design, Setting, and Participants

This randomized, sham-controlled, clinical trial with outcome assessors and patients blinded to treatment assignment, enrolled patients from March 11, 2016, to March 13, 2020. This was an international, multicenter study conducted in the US and Europe. Participants with daytime ambulatory BP of 135/85 mm Hg or higher after 4 weeks of single-pill triple-combination treatment (angiotensin-receptor blocker, calcium channel blocker, and thiazide diuretic) with estimated glomerular filtration rate (eGFR) of 40 mL/min/1.73 m2 or greater were randomly assigned to uRDN or sham with medications unchanged through 2 months. From 2 to 5 months, if monthly home BP was 135/85 mm Hg or higher, standardized stepped-care antihypertensive treatment starting with aldosterone antagonists was initiated under blinding to treatment assignment.

Interventions

uRDN vs sham procedure in conjunction with added medications to target BP control.

Main Outcomes and Measures

Six-month change in medications, change in daytime ambulatory systolic BP, change in home systolic BP adjusted for baseline BP and medications, and safety.

Results

A total of 65 of 69 participants in the uRDN group and 64 of 67 participants in the sham group (mean [SD] age, 52.4 [8.3] years; 104 male [80.6%]) with a mean (SD) eGFR of 81.5 (22.8) mL/min/1.73 m2 had 6-month daytime ambulatory BP measurements. Fewer medications were added in the uRDN group (mean [SD], 0.7 [1.0] medications) vs sham (mean [SD], 1.1 [1.1] medications; P = .045) and fewer patients in the uRDN group received aldosterone antagonists at 6 months (26 of 65 [40.0%] vs 39 of 64 [60.9%]; P = .02). Despite less intensive standardized stepped-care antihypertensive treatment, mean (SD) daytime ambulatory BP at 6 months was 138.3 (15.1) mm Hg with uRDN vs 139.0 (14.3) mm Hg with sham (additional decreases of -2.4 [16.6] vs -7.0 [16.7] mm Hg from month 2, respectively), whereas home SBP was lowered to a greater extent with uRDN by 4.3 mm Hg (95% CI, 0.5-8.1 mm Hg; P = .03) in a mixed model adjusting for baseline and number of medications. Adverse events were infrequent and similar between groups.

Conclusions and Relevance

In this study, in patients with RHTN initially randomly assigned to uRDN or a sham procedure and who had persistent elevation of BP at 2 months after the procedure, standardized stepped-care antihypertensive treatment escalation resulted in similar BP reduction in both groups at 6 months, with fewer additional medications required in the uRDN group.

Trial Registration

ClinicalTrials.gov Identifier: NCT02649426.

Six-Month Results of Treatment-Blinded Medication Titration for Hypertension Control After Randomization to Endovascular Ultrasound Renal Denervation or a Sham Procedure in the RADIANCE-HTN SOLO Trial

BACKGROUND

The multicenter, international, randomized, blinded, sham-controlled RADIANCE-HTN SOLO trial (A Study of the ReCor Medical Paradise System in Clinical Hypertension) demonstrated a 6.3 mm Hg greater reduction in daytime ambulatory systolic blood pressure (BP) at 2 months by endovascular ultrasound renal denervation (RDN) compared with a sham procedure among patients not treated with antihypertensive medications. We report 6-month results after the addition of a recommended standardized stepped-care antihypertensive treatment to the randomized endovascular procedure under continued blinding to initial treatment.

METHODS

Patients with a daytime ambulatory BP ≥135/85 mm Hg and <170/105 mm Hg after a 4-week discontinuation of up to 2 antihypertensive medications, and a suitable renal artery anatomy, were randomized to RDN (n=74) or sham (n=72). Patients were to remain off antihypertensive medications throughout the first 2 months of follow-up unless safety BP criteria were exceeded. Between 2 and 5 months, if monthly measured home BP was ≥135/85 mm Hg, a standardized stepped-care antihypertensive treatment was recommended consisting of the sequential addition of amlodipine (5 mg/d), a standard dose of an angiotensin-converting enzyme inhibitor/angiotensin receptor blocker, and hydrochlorothiazide (12.5 mg/d), followed by the sequential uptitration of hydrochlorothiazide (25 mg/d) and amlodipine (10 mg/d). Outcomes included the 6-month (1) change in daytime ambulatory systolic BP adjusted for medications and baseline systolic BP, (2) medication burden, and (3) safety.

RESULTS

A total of 69/74 RDN patients and 71/72 sham patients completed the 6-month ambulatory BP measurement. At 6 months, 65.2% of patients in the RDN group were treated with the standardized stepped-care antihypertensive treatment versus 84.5% in the sham group (P=0.008), and the average number of antihypertensive medications and defined daily dose were less in the RDN group than in the sham group (0.9±0.9 versus 1.3±0.9, P=0.010 and 1.4±1.5 versus 2.0±1.8, P=0.018; respectively). Despite less intensive standardized stepped-care antihypertensive treatment, RDN reduced daytime ambulatory systolic BP to a greater extent than sham (-18.1±12.2 versus -15.6±13.2 mm Hg, respectively; difference adjusted for baseline BP and number of medications: -4.3 mm Hg, 95% confidence interval, -7.9 to -0.6, P=0.024). There were no major adverse events in either group through 6 months.

CONCLUSIONS

The BP-lowering effect of endovascular ultrasound RDN was maintained at 6 months with less prescribed antihypertensive medications compared with a sham control.

CLINICAL TRIAL REGISTRATION

URL: https://www.

CLINICALTRIALS

gov. Unique identifier: NCT02649426.

Correlation of Preoperative Ki67 and Serum CA15.3 Levels with Outcome in Early Breast Cancers a Multi Institutional Study

BACKGROUND

To investigate the association between preoperative pathological Ki67 labeling index and serum tumor marker cancer antigen 153 (CA 153) with clinicpathological parameters and treatment outcomes in early breast cancer.

MATERIALS AND METHODS

A retrospective study at 4 cancer centers in Saudi Arabia and Egypt was performed. Data were collected for female patients diagnosed with unilateral early breast cancer between March 2010 and October 2013. Cases treated with neoadjuvant chemotherapy (NACT) followed by surgery and radiotherapy were included. NACT included 68 cycles of anthracycline and taxane based regimens. Trastuzumab and hormonal treatments were added according to HER2 and hormone receptor status. Baseline serum CA15.3 and pathological Ki67 levels were evaluated and correlated with disease free survival (DFS) and overall survival (OS).

RESULTS

A total of 280 pts was included. The median age was 49 years (3866 y) and median overall survival was 35 (2038) months (mo). Estrogen receptors (ER), progesterone receptors (PR) and HER 2 receptors were positive in 233 (83.2%), 198 (70%) and 65 cases (23.2%), respectively. High preoperative Ki67 and CA15.3 were noted in 177 (63.2%) and 131 (46.8%). A total of 45 (16%) patients had distal or local recurrence and 24 (8.6%) died of their disease. Most of the relapsed cases had high preoperative Ki67 (n=41, 91%) and CA15.3 (n=28, 62%) values. All of the patients who died had a high Ki67 but CA15.3 was high in 9 (37%) only. Mean DFS/OS in patients with high preoperative Ki67 was 32 months /32 months as compared to 37 months/35 months in those with normal Ki67 (p<0.001). Correlation of preoperative CA15.3 and survival was statistically not significant.

CONCLUSIONS

Preoperative Ki67 can be a predictive and prognostic marker. Higher levels are associated with poor DFS and OS in patients with early BC.

Results of trastuzumab targeted therapy in metastatic breast cancer (MBC): The Sultanate of Oman experience 2002–2006

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Background: The first random study of incidence of Her-2 over expression among Omani breast cancer patients was carried out by the Medical Oncology Department, the Royal Hospital in 2001. The incidence was reported as 40% (higher than international published figures). The Herceptest was routinely performed on all new patients for a whole year (2004) and the incidence was found to be 36%. Trastuzumab was approved for use in the Sultanate of Oman in 2002, since then a total of 26 patients with metastatic breast cancer received Trastuzumab, the results are presented. Methods: Prospective, single arm, single centre experience. Patients with confirmed metastatic breast cancer (at presentation or after adjuvant treatment), HER-2 positive (+++ by Herceptest, or FISH positive), age > 18, ECOG PS ≤ 2, LVEF = 50% and adequate renal & liver function, were included. Treatment consisted of trastuzumab as single agent or in combination with chemotherapy as indicated. A loading dose of 8mg/kg was followed by 6mg/kg q3 weeks. The endpoints were response rate (RR) progression free survival (PFS) and survival (OS). Results: a total of 26 patients were included between October 2002-October 2006, median age was 45.5years (27–60), 12 patients presented with metastasis at first presentation and 14 had metastatic disease 6 months or more after finishing adjuvant chemotherapy. The median number of received cycles was 10 (range 4–30), the overall response rate was 77% (54% CR and 23% PR), the median survival 15 months (range 4–36m), median Time to Progression 9m (range 4–33m). Six patients (23%) developed brain metastasis while on herceptin. There were 8 events (disease related deaths) during the study period. Conclusions: The incidence of Her-2 +ve breast cancer in Omani patients is slightly higher than the reported figures in international studies. The response to trastuzumab in metastatic disease is comparable to other similar studies.

No significant financial relationships to disclose.

Evaluation of the prevalence, pattern and management of cancer pain in Oncology Department, The Royal Hospital, Oman

INTRODUCTION

Pain is under-treated in all parts of the world. Moderate to severe pain is experienced by the majority of patients with advanced disease. The aim of this study is to evaluate the prevalence, pattern and pain management in Oman.

METHODS

A prospective study was carried out during a 3 months period. We evaluated all admitted patients and only patients who were complaining of pain were eligible. Assessment of pain intensity and pain relief were done using measuring scales. All patients received pharmacological treatment according to WHO analgesic ladder.

RESULTS

A total of 335 admissions were recorded during the study period of which 100 patients (30%) were eligible for the study, 52% of cases were males. The mean age was 45 years +/- 16.2 years and the most common tumours were GIT and breast cancer. Sixty four patients had pain but did not complain about it. Forty-five patients (45%) had moderate pain but they did not routinely complain about it. The mean hospital stay was 3.5 days and the range 1- 10 days.

CONCLUSIONS

Most cancer patients deny pain for various reasons. Thorough history and repeated pain assessment are very important. Following the WHO analgesic ladder is simple and effective.

Long-term efficacy and safety of fluticasone propionate powder administered once or twice daily via inhaler to patients with moderate asthma

OBJECTIVE

To evaluate the efficacy and safety of fluticasone propionate administered as a once-daily or twice-daily regimen over a period of 1 year to patients with moderate asthma.

DESIGN

Double-blind, randomized, parallel group, and placebo-controlled phase (12 weeks) and an open-label phase (54 weeks).

SETTING

Multicenter study in an outpatient setting.

PARTICIPANTS

Patients (n = 253; age, > or = 12 years) with a mean FEV(1) of 67% predicted normal were stratified according to baseline therapy of maintenance inhaled corticosteroids vs beta(2)-agonists alone.

MEASUREMENTS AND INTERVENTIONS

Fluticasone propionate (250 microg bid or 500 microg qd) or placebo (bid) was administered via the Diskus multidose powder inhaler (Glaxo Wellcome; Research Triangle Park, NC) for 12 weeks. During open-label treatment, patients were re-randomized to once-daily or twice-daily fluticasone propionate.

RESULTS

Compared to placebo, fluticasone propionate administered qd or bid significantly improved FEV(1) (p < 0.001), morning (p < 0.001) and evening peak expiratory flow (PEF; p < 0.001), asthma symptom scores (p < or = 0.001), and albuterol use (p </= 0.001), and decreased nighttime awakenings. By the end of 12 weeks, withdrawal due to lack of efficacy was significantly higher in the placebo group than in the once-daily (p = 0.001) or twice-daily (p < 0.001) groups. When comparing the two active dosing regimens, significant differences in favor of twice-daily dosing were noted in FEV(1), albuterol use, and withdrawal due to lack of efficacy. During 54 weeks of open-label treatment, FEV(1) and PEF continued to improve with both regimens, and improvements seen in the first 12 weeks were maintained in patients who switched from twice-daily to once-daily dosing. Fluticasone propionate treatment over a 54-week period was well tolerated, with few drug-related adverse events, which were primarily topical effects of inhaled corticosteroids.

CONCLUSIONS

Fluticasone propionate powder improved lung function when administered either qd or bid over a 1-year period to patients with moderate asthma, with twice-daily dosing demonstrating significantly greater improvement in some efficacy parameters than once-daily dosing over the first 12 weeks of treatment. Fluticasone propionate treatment was not associated with significant systemic effects.

Inhaled antimicrobial therapy

Although antimicrobial therapy has been administered through the inhaled route for decades, it has always been controversial. There are relatively few accepted indications for this mode of administration. Well-controlled studies of aerosolized antibiotics in cystic fibrosis demonstrate that tobramycin on a cyclical basis may reduce sputum volume, bacterial counts, and improve pulmonary function. Preliminary data indicate that inhaled antibiotic therapy of ventilator-associated tracheobronchitis may reduce sputum volume, but the clinical significance of this finding remains to be determined. Inhaled pentamidine is used for prophylaxis of Pneumocystis carinii in patients with human immunodeficiency virus infection who are intolerant of oral prophylactic agents. Ribavirin has been used for 30 years to treat respiratory syncytial virus. The role, if any, of inhaled antifungal therapy with amphotericin B remains undetermined.

Fas activates the JNK pathway in human colonic epithelial cells: lack of a direct role in apoptosis

Fas is expressed constitutively by colonic epithelial cells, and its ligand is expressed by intraepithelial and lamina propria lymphocytes. Fas ligation induces apoptosis in colonic epithelial cells and is implicated in the epithelial damage seen in ulcerative colitis. To understand the pleiotropic effects of Fas in the intestinal mucosa, we have examined signaling pathways activated by Fas in HT-29 colonic epithelial cells. HT-29 cells were stimulated with anti-Fas in the presence or absence of interferon-gamma (IFN-gamma). Activation of mitogen-activated protein kinase pathways was assessed by kinase assay, Western blots, and promoter-reporter assays. Electromobility shift assays were used to assess activator protein-1 (AP-1) binding activity. IFN-gamma increases expression of Fas on HT-29 cells. Signaling via Fas receptor, as determined by induction of c-Jun NH2-terminal kinase (JNK) activity and transcriptional activation of AP-1, is enhanced in IFN-gamma-primed cells. Dominant-interfering mutants of the JNK pathway do not block Fas-mediated apoptosis. Signaling through Fas results in activation of JNK and AP-1 binding activity that is increased in the presence of IFN-gamma. Inhibition of JNK does not block Fas-mediated apoptosis in these cells. Fas-Fas ligand interactions in the intestinal mucosa may lead to complex signal transduction cascades and gene regulation that culminate in apoptosis, cytokine secretion, or other novel functions.

Stress-induced Fas ligand expression in T cells is mediated through a MEK kinase 1-regulated response element in the Fas ligand promoter

T lymphocytes undergo apoptosis in response to a variety of stimuli, including exposure to UV radiation and gamma-irradiation. While the mechanism by which stress stimuli induce apoptosis is not well understood, we have previously shown that the induction of Fas ligand (FasL) gene expression by environmental stress stimuli is dependent on c-Jun N-terminal kinase (JNK) activation. Using inducible dominant-active (DA) JNK kinase kinase (MEKK1) expression in Jurkat cells, we map a specific MEKK1-regulated response element to positions -338 to -316 of the Fas ligand (FasL) promoter. Mutation of that response element abrogated MEKK1-mediated FasL promoter activation and interfered in stress-induced activation of that promoter. Using electrophoretic mobility shift assays, we demonstrate that activator protein 1 (AP-1) binding proteins, namely, activating transcription factor 2 (ATF2) and c-Jun, bind to the MEKK1 response element. Transient transfection of interfering c-Jun and ATF2 mutants, which lack the consensus JNK phosphorylation sites, abrogated the transcriptional activation of the FasL promoter, demonstrating the involvement of these transcription factors in the regulation of the FasL promoter. Taken together, our data indicate that MEKK1 and transcription factors regulated by the JNK pathway play a role in committing lymphocytes to undergo apoptosis by inducing FasL expression via a novel response element in the promoter of that gene.

Thioredoxin peroxidase (natural killer enhancing factor) regulation of activator protein-1 function in endothelial cells

Thioredoxin peroxidase-1 (TxP-1), originally cloned as natural killer enhancing factor-B, belongs to a highly conserved antioxidant family. Tumor necrosis factor-alpha (TNF) activates the expression of activator protein-1 (AP-1) responsive genes. We show here that over-expression of TxP-1 blocks TNF-induced AP-1 activation in endothelial ECV304 cells, which was demonstrated by three independent experimental protocols: electromobility shift assay with AP-1 oligonucleotide probe; reporter gene expression with AP-1 binding site, and interleukin-8 production, which is dependent on AP-1. These results are consistent with the role of TxP-1 as an antioxidant and the previous reports that TNF-induced reactive oxygen species were responsible for AP-1 activation.

A patient with breast cancer and paraneoplastic cerebellar syndrome associated with anti-Purkinje cell antibodies: response to CMF chemotherapy

A 41-year-old lady underwent a left mastectomy and axillary clearance in 1992, for T2N0 breast cancer. She remained well until December 1995, when she presented with a rapidly progressive cerebellar ataxia. Full investigations for metastatic disease were negative. A clinical diagnosis of paraneoplastic cerebellar degeneration was confirmed by a high titre of anti-Purkinje cell antibodies. She was treated with cyclophosphomide, methotrexate and 5-fluorouracil. The improvement in neurological symptoms was dramatic and has been maintained by further hormone manipulation (ovarian ablation). The patient now leads a normal life without medication.

Macrophage activation by polycyclic aromatic hydrocarbons: evidence for the involvement of stress-activated protein kinases, activator protein-1, and antioxidant response elements

Polycyclic aromatic hydrocarbons (PAH) contained in fossil fuel combustion particles enhance the allergic response to common environmental Ags. A key question is: what are molecular pathways in the immune system by which PAH and conversion products drive allergic inflammation? Circumstantial evidence suggests that macrophages are involved in PAH-induced responses. We demonstrate that a representative PAH, beta-napthoflavone (BNF), and a representative quinone metabolite, tert-butylhydroxyquinone (tBHQ), induce Jun kinase and p38 mitogen-activated protein kinase activities in parallel with the generation of activator protein-1 (AP-1) mobility shift complexes in THP-1 and RAW264.7 macrophage cell lines. Activation of mitogen-activated protein kinases was dependent on generation of oxidative stress, and could be inhibited by N-acetylcysteine. Another genetic response pathway linked to PAH is the antioxidant response element (ARE), which regulates expression of detoxifying enzymes. BNF and tBHQ activated a human ARE (hARE) reporter gene in RAW264.7 cells. Interestingly, bacterial lipopolysaccharide also induced hARE/chloramphenicol acetyltransferase activity. While the hARE core, GTGACTCAGC, contains a consensus AP-1 sequence (underlined), AP-1 was not required for hARE activation. This suggests that PAH and their conversion products operate via ARE-specific transcription factors in the immune system. BNF and tBHQ did, however, induce AP-1 binding to the hARE, while constitutively active Jun kinase interfered in hARE/chloramphenicol acetyltransferase activation. This suggests that AP-1 proteins negatively regulate the hARE. These data establish important activation pathways for PAH in the immune system and provide us with targets to modulate the effect of environmental pollutants on allergic inflammation.

Inflammatory cytokines induce the expression of basic fibroblast growth factor (bFGF) isoforms required for the growth of Kaposi's sarcoma and endothelial cells through the activation of AP-1 response elements in the bFGF promoter

BACKGROUND

The growth of Kaposi's sarcoma (KS) spindle cells is dependent on a number of inflammatory cytokines as well as the autocrine growth factor, basic fibroblast growth factor (bFGF). Moreover, inflammatory cytokines, found at increased levels in KS lesions, promote bFGF production in KS and endothelial cells.

OBJECTIVES

To determine the induction of bFGF isoforms, role of bFGF in cell growth and activation of the bFGF promoter by inflammatory cytokines.

DESIGN AND METHOD

3H-Thymidine uptake, bFGF immunoblotting and transfection of dominant-negative MAP kinase components were used to study the effect of cytokines on the bFGF promoter, bFGF isoform expression and proliferation of KS cells.

RESULTS

Treatment with oncostatin M (OSM), interleukin (IL)-1 and tumor necrosis factor (TNF)-alpha induced the expression of 18, 22 and 24 kDa bFGF isoforms in KS and human umbilical vein endothelial cells (HUVEC). Antisense bFGF oligonucleotides interfered in the induction of KS cell proliferation by individual cytokines. OSM, IL-1 and TNF-alpha induced the transcriptional activation of a bFGF promoter reporter gene in parallel with the activation of an AP-1 reporter. Dominant-negative ERK and dominant-negative JNK mutants interfered in cytokine-induced activation of these reporters in accordance with the role of the MAP kinase cascades in individual cytokine signaling pathways.

CONCLUSIONS

OSM, IL-1 and TNF-alpha induce KS cell growth by inducing the expression of various bFGF isoforms. Moreover, bFGF production by KS and HUVEC is dependent on the activation of the ERK and JNK cascades, which result in the transcriptional activation of the bFGF promoter.

The c-Jun N-terminal kinase cascade plays a role in stress-induced apoptosis in Jurkat cells by up-regulating Fas ligand expression

T lymphocytes undergo apoptosis in response to cellular stress, including UV exposure and gamma irradiation. However, the mechanism by which stress stimuli induce apoptosis is not well understood. While stress stimuli induce the activation of the c-Jun N-terminal kinase (JNK) pathway, it is not clear whether the JNK cascade is activated as a result of cell death or whether the cascade participates in inducing apoptosis. Using a Jurkat T cell line transfected with dominant active (DA)-mitogen-activated protein kinase kinase kinase (MEKK1) in a tetracycline-regulated expression system, we found that expression of DA-MEKK1 results in the apoptosis of Jurkat cells in parallel with prolonged JNK activation. Moreover, DA-MEKK1 induced Fas ligand (FasL) cell surface and mRNA expression, as well as FasL promoter activation. Interference with Fas/FasL interaction prevented DA-MEKK1-mediated apoptosis. In comparing the effect of different stress stimuli to DA-MEKK1, we found that UV, gamma irradiation, and anisomycin prolonged JNK activation in parallel with FasL expression and onset of cell death. In addition, these stimuli also enhance cell surface expression of FasL. Interference with Fas/FasL interactions inhibited anisomycin but not UV- or gamma irradiation-induced apoptosis. Our data show that while the JNK pathway contributes to stress-induced apoptosis in T lymphocytes by regulating FasL expression, not all stress stimuli use the same cell death pathway.

Involvement of Stat3 in interleukin-6-induced IgM production in a human B-cell line

Interleukin-6 (IL-6) is an important B-cell growth and differentiation factor. IL-6 treatment of the human lymphoblastoid cell line, SKW6.4, leads to increased IgM production. We have previously shown that IL-6 induces activation of JAK1 and JAK2 in human B cell lines. A chimeric IL-6 receptor, comprised of the intracellular tail of the IL-6 receptor subunit gp130 fused to the extracellular domain of the epidermal growth factor (EGF) receptor, was stably transfected into SKW6.4 cells. EGF treatment induced IgM production in cells transfected with an intact gp130 cytoplasmic tail, but not in untransfected cells or cells transfected with a cytoplasmic tail lacking all four signal transducers and activators of transcription (Stat) binding sites. Moreover, EGF treatment induced Stat3 phosphorylation in cells transfected with the intact chimeric EGF-gp130 receptor along with induction of DNA-mobility shift of a classical interferon-gamma-activated site. To define further the relation between Stat3 activation and enhanced IgM production, we determined the effect of chimeric gp130 on the transcriptional activation of a genetic element linked to immunoglobulin production, namely the immunoglobulin heavy chain enhancer (IgH-enhancer). Parental as well as transfected SKW6.4 cells were transiently transfected with an IgH-enhancer-luciferase construct. The transcriptional activity of the IgH-luciferase construct was induced upon ligation of the full-length chimeric receptor but not by truncated gp130 receptors. Moreover, the gp130-induced activity of this reporter gene was abrogated by Stat3EE, a mutant Stat3 incapable of binding DNA. These results indicate that IL-6-induced B-cell differentiation, as measured by IgM production, may be controlled by Stat3 proteins.

Regulation of interleukin-2 transcription by inducible stable expression of dominant negative and dominant active mitogen-activated protein kinase kinase kinase in jurkat T cells. Evidence for the importance of Ras in a pathway that is controlled by dual receptor stimulation

Engagement of the T cell receptor induces the activation of several mitogen-activated protein kinase modules, including the extracellular signal-regulated kinase and c-Jun N-terminal kinase (JNK) cascades. Whereas extracellular signal-regulated kinase is activated by T cell receptor/CD3 ligation alone, activation of JNK requires co-stimulation by the CD28 receptor. Activation of MEKK-1, which acts as a mitogen-activated protein kinase kinase kinase in the JNK pathway, was also induced by CD3 plus CD28 (CD3/CD28) ligation in Jurkat cells. To study the significance of the JNK cascade in T lymphocytes, we established stable Jurkat cell lines that inducibly express dominant active (DA) or dominant negative (DN) MEKK-1. Whereas expression of DA-MEKK-1 resulted in the constitutive activation of JNK along with the transcriptional activation of the minimal interleukin-2 (IL-2) promoter, DN-MEKK-1 inhibited JNK responsiveness during CD3/CD28 co-stimulation. In addition to inhibiting CD3/CD28-induced IL-2 mRNA expression, DN-MEKK-1 abrogated the transcriptional activation of the IL-2 promoter and the distal nuclear factor of activated T cells (NFAT)-activating protein 1 (AP-1) response element in that promoter. A c-Jun mutant lacking activation sites for JNK also interfered with the activation of the distal NFAT/AP-1 complex, suggesting that the JNK pathway functions by controlling AP-1 response elements in the IL-2 promoter. Using inducible stable expression of DA- and DN-Ras in Jurkat cells, we found that Ras regulates JNK activation in these cells. Our results suggest that the dual ligation of CD3 and CD28 in T cells triggers a cascade of events that involve Ras, the JNK cascade, and one or more AP-1 response elements in the IL-2 promoter.

Differential activation of the extracellular signal-regulated kinase, Jun kinase and Janus kinase-Stat pathways by oncostatin M and basic fibroblast growth factor in AIDS-derived Kaposi's sarcoma cells

OBJECTIVES

To determine the integration of signalling pathways associated with two recognized Kaposi's sarcoma (KS) growth factors, oncostatin M (OSM) and basic fibroblast growth factor (bFGF), in the induction of KS cell proliferation.

DESIGN AND METHODS

We used protein kinase assays, protein-DNA interactions and AP-1 luciferase assays to study the extracellular signal-regulated kinase (ERK), Janus kinase (JAK)-Stat and Jun kinase (JNK) pathways in AIDS-derived KS cells during stimulation with OSM and bFGF.

RESULTS

Treatment with OSM-induced activation of receptor-associated JAK and phosphorylation of Stat1 and Stat3. Stat1/Stat3 heterodimers interacted with known gamma-interferon-activated sites like elements such as the sis-inducible element (SIE) in the C-fos promoter. In contrast, ligation of the bFGF receptor induced Stat3 phosphorylation and its association with the bFGF receptor, but failed to induce JAK activity or protein complexes which interact with GAS-like oligonucleotides. OSM also induced the activation of ERK2 by activating the serine/threonine kinases Raf-1 and [mitogenactivated protein kinase (MAPK) ERK kinase (MEK1)]-1, while bFGF failed to activate any of the above components. Both OSM and bFGF activated the JNK pathway, along with the activation of MEKkinase (MEKK)-1. JNK control the transcriptional activation of c-Jun. Because the above pathways exert an effect on the expression or activation of activation protein (AP)-1 components, we confirm that OSM and bFGF induce TPA response element (TRE)-luciferase activity synergistically.

CONCLUSION

We demonstrate that OSM and bFGF activate distinct as well as shared signalling cascades in KS cells, which integrate to provide a synergistic AP-1 response by which OSM and bFGF may sustain KS cell growth.

CD40 signaling pathway: anti-CD40 monoclonal antibody induces rapid dephosphorylation and phosphorylation of tyrosine-phosphorylated proteins including protein tyrosine kinase Lyn, Fyn, and Syk and the appearance of a 28-kD tyrosine phosphorylated protein

CD40 plays an important role in B cell activation, proliferation, and Ig class switching. The signal transduction pathway mediated by CD40 was studied using monoclonal antibody (mAb) 626.1 to CD40. Burkitt's lymphoma and Epstein-Barr virus-transformed B cell lines and tonsilar B lymphocytes were treated with the anti-CD40 mAb for various lengths of time. The early events triggered by CD40 were examined by monitoring the changes in tyrosine phosphorylation of cellular proteins with anti-phosphotyrosine mAb. Dephosphorylation of specific proteins ranging between 50-110 kD and the appearance of a 28-kD tyrosine phosphorylated protein were seen within 30 s in human B cell lines. The dephosphorylation was reversed and the 28-kD protein was dephosphorylated in cells stimulated for 1 min. In resting B cells, the appearance of the 28-kD phosphoprotein was observed in 30 s after the addition of the anti-CD40 mAb. The tyrosine phosphorylation of this protein persisted. The patterns of protein tyrosine phosphorylation differed from those induced by an anti-immunoglobulin M mAb. The changes in the state of tyrosine phosphorylation induced by the anti-CD40 mAb were obviated by mAb to CD45, a protein tyrosine phosphatase (PTP) or by the addition of sodium orthovanadate, a broad PTP inhibitor. They were also blocked by protein tyrosine kinase (PTK) inhibitors, herbimycin A and genistein, and PKC and protein serine/threonine kinase inhibitors, H7 and HA1004. In addition, the alteration in the tyrosine phosphorylation of PTKs Lyn, Fyn, and Syk was directly demonstrated. Engagement of CD40 for 30 s induced a transient decrease in tyrosine phosphorylation of these PTKs. These results indicate that the early events in CD40 signaling involve the complex interaction between PTP and protein kinases.

The induction of persistence of I-A expression by macrophages from Bcgr mice occurs via a protein kinase C-dependent pathway

We have described conditions by which MHC class II (I-A) glycoproteins can be induced to be differentially expressed after treatment of macrophages with rIFN-gamma. Treatment of macrophages from BCG-resistant mice with 1 U of rIFN-gamma induced transient I-A expression that decayed in the presence of cycloheximide. Subsequent treatment of these macrophages with 100 U of rIFN-gamma induced the persistence of I-A that was not affected by cycloheximide. The aim of this investigation was to define, by pharmacologic intervention, the second signals that resulted in the induction of persistence of I-A. Treatment of the macrophages that transiently expressed I-A with PMA resulted in the induction of persistence. When we compared the effect of different protein kinase C (PKC) inhibitors with the induction of persistence by rIFN-gamma, we found that H-7 blocked the induction of persistence only when added before or at the same time as the addition of a high dose of rIFN-gamma. In contrast, the addition of staurosporine to macrophages as late as 2 h after treatment with high doses of rIFN-gamma inhibited the induction of I-A persistence. The addition of a high dose of rIFN-gamma to macrophages previously treated with a low dose of rIFN-gamma resulted in the synergistic activation of PKC. The effect of H-7 and of staurosporine on the activation of PKC activity coincided with the effect of these inhibitors on the induction of persistent I-A expression. Tyrosine kinase inhibitors genistein and herbimycin did not affect the induction of I-A persistence nor of PKC activation. Antibody to the IFN-gamma receptor inhibited PKC activation. Finally, the addition of the high dose of rIFN-gamma to macrophages from BALB/c.Bcgs mice, previously treated with the low dose of rIFN-gamma, failed to activate high levels of PKC activity attained after similar treatment of macrophages from BALB/c.Bcgr mice. One effect of the Bcg gene may be to regulate the activation of PKC activity.

The induction of persistence of I-A expression by macrophages from Bcgr mice occurs via a protein kinase C-dependent pathway

We have described conditions by which MHC class II (I-A) glycoproteins can be induced to be differentially expressed after treatment of macrophages with rIFN-gamma. Treatment of macrophages from BCG-resistant mice with 1 U of rIFN-gamma induced transient I-A expression that decayed in the presence of cycloheximide. Subsequent treatment of these macrophages with 100 U of rIFN-gamma induced the persistence of I-A that was not affected by cycloheximide. The aim of this investigation was to define, by pharmacologic intervention, the second signals that resulted in the induction of persistence of I-A. Treatment of the macrophages that transiently expressed I-A with PMA resulted in the induction of persistence. When we compared the effect of different protein kinase C (PKC) inhibitors with the induction of persistence by rIFN-gamma, we found that H-7 blocked the induction of persistence only when added before or at the same time as the addition of a high dose of rIFN-gamma. In contrast, the addition of staurosporine to macrophages as late as 2 h after treatment with high doses of rIFN-gamma inhibited the induction of I-A persistence. The addition of a high dose of rIFN-gamma to macrophages previously treated with a low dose of rIFN-gamma resulted in the synergistic activation of PKC. The effect of H-7 and of staurosporine on the activation of PKC activity coincided with the effect of these inhibitors on the induction of persistent I-A expression. Tyrosine kinase inhibitors genistein and herbimycin did not affect the induction of I-A persistence nor of PKC activation. Antibody to the IFN-gamma receptor inhibited PKC activation. Finally, the addition of the high dose of rIFN-gamma to macrophages from BALB/c.Bcgs mice, previously treated with the low dose of rIFN-gamma, failed to activate high levels of PKC activity attained after similar treatment of macrophages from BALB/c.Bcgr mice. One effect of the Bcg gene may be to regulate the activation of PKC activity.

Characterization of the induction of persistence of major histocompatibility complex class II by hybrids of macrophages from bacillus Calmette Guerin-resistant mice

Peritoneal macrophages (M phi) from mice that are resistant to infection by Mycobacterium bovis (strain BCG) (Bcgr) can be induced to express major histocompatibility complex (MHC) class II glycoproteins (I-A) continuously upon treatment with 100 units of recombinant interferon-gamma (rIFN-gamma). In contrast, M phi from mice that are susceptible to BCG (Bcgs) express I-A transiently. Persistent expression of I-A does not require the continued synthesis of the glycoprotein. Thus, treatment with cycloheximide (CHX) reduces I-A expression by M phi that express I-A transiently but does not affect the expression of I-A that is persistently expressed. It was not possible, in these studies, to characterize the induction of persistence independent of MHC class II expression because of the 24-48 h required for MHC class II synthesis and cycling to the cell surface. During this time, persistence was also induced. To characterize persistence independent of MHC class II induction we have produced M phi-M phi somatic cell hybrids that express I-A constitutively by fusing cells from a Bcgs M phi cell line with M phi from Bcgr mice. Treatment of some of the hybrids with CHX reduced MHC class II expression. The M phi hybrids required treatment with high doses of rIFN-gamma to induce CHX-resistant I-A expression. The induction of the persistence of I-A, following the addition of rIFN-gamma, required a short burst of protein synthesis as well as the presence of rIFN-gamma for at least 3 h. The addition of actinomycin D simultaneously with rIFN-gamma did not prevent the induction of the persistence of I-A expression by one of the M phi hybrids (F6.4). In contrast, the induction of persistence of I-A expression required a longer period of induction than was observed for hybrid F6.4, which was attributed to the requirement for new RNA and protein synthesis by the A1.8 hybridoma.

Characterization of the induction of persistent I-A expression by macrophages from Bcgr mice

Peritoneal macrophages from mice that are resistant to Mycobacterium bovis (strain BCG) [Gros et al., J. Immunol. 127,2417, 1981] can be induced to express persistently or transiently major histocompatibility complex (MHC) class II glycoproteins. The induction of persistent expression is dependent on the dose of recombinant interferon-gamma (rIFN-gamma). High doses of rIFN-gamma (100 U) induce persistent Ia expression, whereas lower doses induce only transient Ia expression. Once induced, the persistent expression of Ia does not require its continued synthesis. We show that the expression of Ia by macrophages that transiently express MHC class II glycoproteins is reduced by the addition of cycloheximide or monensin, whereas Ia expression by macrophages that persistently express Ia is not affected. The differential sensitivity of Ia expression to cycloheximide was used to study the induction of persistence that is linked to the Bcg gene. Macrophages were primed with low doses of rIFN-gamma in order to induce transient, cycloheximide-sensitive Ia expression. The cells were then treated with high doses of rIFN-gamma in order to induce persistent, cycloheximide-resistant Ia expression. We found that the induction of persistent Ia expression requires at least 3 hr of exposure to rIFN-gamma. Furthermore, the addition of rIFN-gamma to primed macrophages is followed by a short burst of protein synthesis that is independent of the production of new mRNA. The rapidity with which persistent Ia expression is induced is consistent with the rapid onset of innate resistance to Mycobacterium following injection of BCG.

Differential effect of restraint stress on MHC class II expression by murine peritoneal macrophages

The effect of restraint stress on the expression of MHC class II glycoproteins by peritoneal macrophages was evaluated. Restraint suppressed the expression of I-A by macrophages from mice that are susceptible to Mycobacterial infection. In contrast, restraint did not affect I-A expression by macrophages from resistant mice. The suppression of MHC class II expression required at least 8 h of restraint and recovered within 4 h after stress. The amount of restraint necessary to suppress I-A expression also resulted in higher levels of plasma corticosterone. Changes in I-A expression were under circadian rhythm control. The differences in the effect of restraint stress on expression of I-A by peritoneal macrophages from resistant and susceptible mice may, in part, be due to differences in the effect of corticosterone in MHC class II expression.

Restraint stress-induced suppression of major histocompatibility complex class II expression by murine peritoneal macrophages

The macrophage plays a central role in the development of immune responses. Macrophages take up and process antigen which is presented to antigen-responsive T lymphocytes in association with major histocompatibility complex class II (Ia) glycoproteins. We have investigated the effect of restraint stress on Ia expression by murine peritoneal macrophages. Stress resulted in a suppression of Ia expression which coincided with an increase in plasma corticosterone levels. In vitro experiments indicate that suppression of Ia expression can occur within 2 h after exposure to corticosterone. The suppression of this important aspect of macrophage function by stressors has important implications regarding the possible immunosuppressive effects of stress on the response of lymphocytes to antigens that depend on intact macrophage function.

Somatic cell hybrids between macrophages from Bcgr and Bcgs mice: characterization of MHC class II expression

In order to gain a better understanding of the regulation of MHC class II expression related to the Bcg gene, we have produced macrophage-macrophage somatic cell hybrids by fusing the RAW 309 macrophage cell line derived from BALB/c.Bcgs mice with peritoneal macrophages from Bcgr C3H/HeN mice. The differential screening of the hybrids was based on the differential sensitivity of Ia expression to suppression with cycloheximide. We found that most of the hybrids expressed Ia without further stimulation with rIFN-gamma. Cycloheximide suppressed the expression of Ia by some of the hybrids. Treatment of these cells with rIFN-gamma resulted in a cycloheximide resistant Ia expression of both parental haplotypes. The macrophage hybrids produced IL-1 beta, IL-1 alpha, and TNF-alpha when stimulated with LPS. There was no correlation between the levels of monokines produced and the persistence of Ia expression. The results of this investigation indicate that the product of the Bcg gene contributed by macrophages from C3H/HeN mice will affect the expression of the I-Ad glycoprotein that is normally transiently expressed by the RAW 309 cell line.