Ketamine Produces Antidepressant Effects by Inhibiting Histone Deacetylases and Upregulating Hippocampal Brain-Derived Neurotrophic Factor Levels in a Diisopropyl Fluorophosphate-Based Rat Model of Gulf War Illness

Approximately one-third of Gulf War veterans suffer from Gulf War Illness (GWI), which encompasses mood disorders and depressive symptoms. Deployment-related exposure to organophosphate compounds has been associated with GWI development. Epigenetic modifications have been reported in GWI veterans. We previously showed that epigenetic histone dysregulations were associated with decreased brain-derived neurotrophic factor (BDNF) expression in a GWI rat model. GWI has no effective therapies. Ketamine (KET) has recently been approved by the Food and Drug Administration for therapy-resistant depression. Interestingly, BDNF upregulation underlies KET's antidepressant effect in GWI-related depression. Here, we investigated whether KET's effect on histone mechanisms signals BDNF upregulations in GWI. Male Sprague-Dawley rats were injected once daily with diisopropyl fluorophosphate (DFP; 0.5 mg/kg, s.c., 5 days). At 6 months following DFP exposure, KET (10 mg/kg, i.p.) was injected, and brains were dissected 24 hours later. Western blotting was used for protein expression, and epigenetic studies used chromatin immunoprecipitation methods. Dil staining was conducted for assessing dendritic spines. Our results indicated that an antidepressant dose of KET inhibited the upregulation of histone deacetylase (HDAC) enzymes in DFP rats. Furthermore, KET restored acetylated histone occupancy at the Bdnf promoter IV and induced BDNF protein expression in DFP rats. Finally, KET treatment also increased the spine density and altered the spine diversity with increased T-type and decreased S-type spines in DFP rats. Given these findings, we propose that KET's actions involve the inhibition of HDAC expression, upregulation of BDNF, and dendritic modifications that together ameliorates the pathologic synaptic plasticity and exerts an antidepressant effect in DFP rats. SIGNIFICANCE STATEMENT: This study offers evidence supporting the involvement of epigenetic histone pathways in the antidepressant effects of ketamine (KET) in a rat model of Gulf War Illness (GWI)-like depression. This effect is achieved through the modulation of histone acetylation at the Bdnf promoter, resulting in elevated brain-derived neurotrophic factor expression and subsequent dendritic remodeling in the hippocampus. These findings underscore the rationale for considering KET as a potential candidate for clinical trials aimed at managing GWI-related depression.

Chronic Epilepsy and Mossy Fiber Sprouting Following Organophosphate-Induced Status Epilepticus in Rats

Organophosphate (OP) compounds are highly toxic and include pesticides and chemical warfare nerve agents. OP exposure inhibits the acetylcholinesterase enzyme, causing cholinergic overstimulation that can evolve into status epilepticus (SE) and produce lethality. Furthermore, OP-induced SE survival is associated with mood and memory dysfunction and spontaneous recurrent seizures (SRS). In male Sprague-Dawley rats, we assessed hippocampal pathology and chronic SRS following SE induced by administration of OP agents paraoxon (2 mg/kg, s.c.), diisopropyl fluorophosphate (4 mg/kg, s.c.), or O-isopropyl methylphosphonofluoridate (GB; sarin) (2 mg/kg, s.c.), immediately followed by atropine and 2-PAM. At 1-hour post-OP-induced SE onset, midazolam was administered to control SE. Approximately 6 months after OP-induced SE, SRS were evaluated using video and electroencephalography monitoring. Histopathology was conducted using hematoxylin and eosin (H&E), while silver sulfide (Timm) staining was used to assess mossy fiber sprouting (MFS). Across all the OP agents, over 60% of rats that survived OP-induced SE developed chronic SRS. H&E staining revealed a significant hippocampal neuronal loss, while Timm staining revealed extensive MFS within the inner molecular region of the dentate gyrus. This study demonstrates that OP-induced SE is associated with hippocampal neuronal loss, extensive MFS, and the development of SRS, all hallmarks of chronic epilepsy. SIGNIFICANCE STATEMENT: Models of organophosphate (OP)-induced SE offer a unique resource to identify molecular mechanisms contributing to neuropathology and the development of chronic OP morbidities. These models could allow the screening of targeted therapeutics for efficacious treatment strategies for OP toxicities.

OP0011 HIGHLY DIFFERENTIATED CD4 AND CD8 T EFFECTOR MEMORY CELLS RE-EXPRESSING CD45RA (TEMRA) ARE ASSOCIATED WITH ACTIVE DISEASE REFRACTORY TO ANTI-TNF THERAPY IN RHEUMATOID ARTHRITIS

Background

Highly differentiated T cells have been reported to be enriched in rheumatoid arthritis (RA) compared to healthy individuals1. The role of terminally differentiated T effector memory re-expressing CD45RA (Temra) in RA pathogenesis and disease activity is still unclear, including whether they can be used as a marker of sustained disease activity in RA patients receiving anti-TNF therapy.

Objectives

To investigate whether the frequency of peripheral blood Temra can be used as a biomarker to identify disease refractory to anti-TNF therapy in RA, if they correlate with inflammation in anti-TNF treated patients, and whether they associate with a flare following tapering anti-TNF.

Methods

RA patients on anti-TNF therapy were recruited from rheumatology clinic (cross-sectional cohort). Clinical data and whole blood were collected. Patients were stratified based on disease activity. Remission was defined as no recorded DAS28-CRP≥2.4, no swollen joints, no C-reactive protein (CRP) of >5mg/L, and on a stable DMARD dose and no reported disease flare/loss of remission in the 6 months prior. Non-remission was defined as any other disease activity which does not fulfil the remission definition. Patients on abatacept, or methotrexate monotherapy and healthy volunteers were recruited as comparison groups. A separate cohort of anti-TNF patients (longitudinal cohort) who have been in remission on a stable dose of anti-TNF for ≥6 months and no use of corticosteroids in the last 6 months, was also recruited. Whole blood was obtained prior to dose tapering (dose halving) and at the point of a flare. Whole blood was processed by gradient centrifugation to obtain peripheral blood mononuclear cells (PBMC). PBMC were stained with fluorochrome-conjugated antibodies for multi-parameter flow cytometry. Analysis was performed on live lymphocytes using FlowJo software version 10.8. Two-tailed Mann-Whitney U test or unpaired t-test were used to obtain unadjusted values, analysis of variance (ANOVA) of log-transformed data was used to obtain age-adjusted values, Spearman’s rank correlation was used to compare correlation between Temra and CRP.

Results

RA patients (36 anti-TNF, 12 abatacept, 16 methotrexate monotherapy) and 14 healthy individuals were recruited. There was a higher proportion of CD4 (age-adjusted p = 0.004) and CD8 Temra (age-adjusted p = 0.0007) in RA patients on anti-TNF with persistent disease activity compared to those who had achieved remission. These differences were confirmed when analysing absolute numbers of CD4 and CD8 Temra. Unexpectedly, the difference in Temra frequency between remission and non-remission RA was not observed in patients treated with methotrexate or abatacept. The median CD4 and CD8 Temra frequencies in RA patients in remission with all treatments studied were similar to healthy individuals.

Temra were not observed to increase with age in the anti-TNF, abatacept, or methotrexate cohorts in contrast to previous reports in healthy individuals2. The frequency of CD4 and CD8 Temra correlated with CRP only in patients on anti-TNF (CD4 Temra Spearman r = 0.5185, p = 0.001, and CD8 Temra Spearman r = 0.5040, p = 0.005).

There was an increase in CD4 (p = 0.003) but not CD8 Temra at 3 months in patients who flared on tapering anti-TNF compared to those who remained in remission (Figure 1).

Conclusion

Increased CD4 and CD8 Temra frequency were associated with persistent disease activity in anti-TNF treated patients but not with other DMARD therapies (abatacept and methotrexate). CD4 Temra increased in those who flared on tapering anti-TNF. These results suggest that Temra may play a role in driving persistent disease activity refractory to anti-TNF therapy rather than merely a marker of inflammation.

References

[1]Weyand CM, Yang Z, Goronzy JJ. T-cell aging in rheumatoid arthritis. Curr Opin Rheumatol. 2014;26(1):93-100.

[2]Callender LA, Carroll EC, Bober EA, et al. Mitochondrial mass governs the extent of human T cell senescence. Aging Cell. 2020;19(2):e13067.

Acknowledgements

SAY is funded by research grants by Versus Arthritis, Royal College of Physicians/Rosetrees Trust, NIHR University College London Hospitals Biomedical Research Centre and UCLH Charities.

Disclosure of Interests

Su-Ann Yeoh: None declared, James Kimpton: None declared, Muhammad Shipa: None declared, Eleanor Hawkins: None declared, Arne Akbar Grant/research support from: AA has received funding from the Leo Skin Foundation (Denmark), Michael Ehrenstein Consultant of: MRE has received consultancy fees from Galapagos and Sanofi., Grant/research support from: MRE has received financial grants from GlaxoSmithKline.

Epigenetic histone acetylation and Bdnf dysregulation in the hippocampus of rats exposed to repeated, low-dose diisopropylfluorophosphate

AIMS

Deployment-related exposures to organophosphate (OP) compounds are implicated for Gulf War Illness (GWI) development in First GW veterans. However, reasons for the persistence of GWI are not fully understood. Epigenetic modifications to chromatin are regulatory mechanisms that can adaptively or maladaptively respond to external stimuli. These include DNA methylation and histone acetylation. DNA methylation changes have been reported in GWI but the role of histone acetylation in GWI has been less explored, despite its importance as an epigenetic mechanism for neurological disorders.

MAIN METHODS

Male Sprague-Dawley rats were exposed to OP diisopropyl fluorophosphate (DFP, 0.5 mg/kg s.c., 5-d) and 6-m later brains were dissected for hippocampus. Western blotting, activity assays and chromatin immunoprecipitation (ChIP) were utilized for epigenetic analyses. Behavior was assessed using the Forced Swim Test (FST) and the Elevated Plus Maze (EPM).

KEY FINDINGS

We observed a significant upregulation in HDAC1 protein along with a significant increase in HDAC enzyme activity in the hippocampus of DFP rats. A locus-specific ChIP study revealed decreases in H3K9ac at the brain derived neurotrophic factor (Bdnf) promoter IV coupled with a significant decrease in BDNF protein in DFP rat hippocampus. Treatment with HDAC inhibitor valproic acid reduced HDAC activity and decreased the FST immobility time in DFP rats.

SIGNIFICANCE

Our research suggests that epigenetic alterations to histone acetylation pathways and decreased BDNF expression could represent novel mechanisms for GWI symptomatology and may provide new targets for developing effective drugs for GWI treatment.

AB0220 ANTI-CITRULLINATED PROTEIN ANTIBODY (ACPA) POSITIVITY IS ASSOCIATED WITH REDUCED WITHDRAWAL RATES OF ABATACEPT IN RHEUMATOID ARTHRITIS BUT ONLY IN PATIENTS WHO ARE ANTI-NUCLEAR ANTIBODY (ANA) NEGATIVE

Background:

Abatacept, a selective inhibitor of T cell co-stimulation, is often used as a second-line biologic disease-modifying anti-rheumatic drug (bDMARD) after the failure of tumour necrosis factor inhibitor (TNFi) in Rheumatoid Arthritis (RA). However, in comparison to TNFi very few survival analyses of abatacept have been reported.1,2

Objectives:

To investigate predictors of abatacept discontinuation due to either inefficacy or adverse events in RA patients over 5-years.

Methods:

A retrospective observational analysis was conducted on a tertiary hospital dataset of RA (according to 2010 ACR/EULAR criteria) patients who started abatacept (either intravenous or subcutaneous). Time to abatacept discontinuation over 5-years was estimated using Kaplan-Meier survival analyses. A multivariate cox-regression model to predict abatacept discontinuation was chosen by elastic net regularisation.

Results:

A total of 112 patients with RA [81% female, mean age 58.1 (SD 13.5) years] commenced abatacept therapy during the study period. 88 (78.6%) patients received intravenous abatacept, 14 (15.9%) of whom switched to subcutaneous injection, and 24 (21.4%) were initially treated with subcutaneous abatacept, 2 (8.3%) of whom switched to intravenous. More than half of the patients (65/112) were treated with at least one concomitant conventional synthetic DMARD (csDMARD). Methotrexate was the most commonly used (n = 37) csDMARD, followed by hydroxychloroquine (n = 23), sulfasalazine (n= 15), and leflunomide (n = 7). 42 (37.5%) patients were treated with glucocorticoids (either oral, intra-articular, or intramuscular injection) during the time they were treated with abatacept. Abatacept was most commonly used as 4th (n = 29) and 3rd line (n = 24) bDMARD but 19 patients received abatacept as their first line bDMARD. 75 (67%) patients were rheumatoid factor (RF) positive and 73 (65.2%) were anti-citrullinated protein antibody (ACPA) positive. Anti-nuclear antibody (ANA) was positive in 32 patients. Abatacept was discontinued in 54 patients (48.2%); 19 (35.2%) due to an adverse event and 35 (64.8%) due to loss of efficacy. Overall, the median time to discontinuation of abatacept was 3.8 years.

Multivariate cox regression (variables chosen by the elastic net and adjusted by whether or not abatacept was used as first-line therapy) showed that ACPA positivity was associated with a reduced risk of abatacept discontinuation with a hazard ratio (HR) of 0.40 (95% CI 0.18 to 0.85, p=0.02, N. of events 16/47) compared to ACPA negative patients (N. of events 15/23), but only if ANA was negative. In contrast, ACPA positivity did not reveal any retention benefit over ACPA negative patients, if they were ANA positive.

ACPA positive patients without positive ANA increased the time-to-discontinuation of abatacept predominantly after 3-months (unadjusted log-rank p=0.02), compared to ACPA, and ANA negative patients (Figure 1). Adding csDMARDs with abatacept, reduced the risk of discontinuation of abatacept by 59% (95% CI 24% to 77%, p = 0.004, N. of events 26/65) compared to monotherapy (N. of events 28/47).

Conclusion:

Our data suggests patients who are ACPA positive and ANA negative are more likely to remain on abatacept therapy. Concomitant csDMARD use also acts as a positive predictor of abatacept treatment retention.

References:

[1]Cagnotto G, et al. Arthritis Res Ther. 2020;22(1):15.

[2]Alten R, et al. Clin Rheumatol. 2019;38(5):1413-1424.

Figure 1.

Kaplan-Meier survival curve of retention of abatacept, stratified by Anti-citrullinated protein antibody (ACPA) and antinuclear antibody (ANA).+ACPA/-ANA = ACPA positive and ANA negative, +ACPA/+ANA = ACPA positive and ANA positive, -ACPA/-ANA = ACPA negative and ANA negative, -ACPA/+ANA = ACPA negative and ANA positive, HR = Hazard ratio.

Acknowledgements:

I have no acknowledgements to declare.

Disclosure of Interests:

None declared

POS1465-HPR THE RELATIONSHIP BETWEEN SEDENTARY BEHAVIOR AND SLEEP IN RHEUMATOID ARTHRITIS: A CROSS-SECTIONAL STUDY

Background:

Rheumatoid arthritis (RA) is a chronic, autoimmune inflammatory condition that affects 0.5% of the adult population worldwide (1). Sedentary behavior (SB) is any waking behavior characterized by an energy expenditure of ≤1.5 METs (metabolic equivalent) and a sitting or reclining posture, e.g. computer use (2) and has a negative impact on health in the RA population (3). Sleep is an important health behavior, but sleep quality is an issue for people living with RA (4, 5). Poor sleep quality is associated with low levels of physical activity in RA (4) however the association between SB and sleep in people who have RA has not been examined previously.

Objectives:

The aim of this study was to investigate the relationship between SB and sleep in people who have RA.

Methods:

A cross-sectional study was conducted. Patients were recruited from rheumatology clinics in a large acute public hospital serving a mix of urban and rural populations. Inclusion criteria were diagnosis of RA by a rheumatologist according to the American College of Rheumatology criteria age ≥ 18 and ≤ 80 years; ability to mobilize independently or aided by a stick; and to understand written and spoken English. Demographic data on age, gender, disease duration and medication were recorded. Pain and fatigue were measured by the Visual Analogue Scale (VAS), anxiety and depression were assessed using the Hospital Anxiety and Depression Scale (HADS), and sleep quality was assessed using the Pittsburgh Sleep Quality Index. SB was measured using the ActivPAL4™ activity monitor, over a 7-day wear period. Descriptive statistics were calculated to describe participant characteristics. Relationships between clinical characteristics and SB were examined using Pearson’s correlation coefficients and regression analyses.

Results:

N=76 participants enrolled in the study with valid data provided by N=72 participants. Mean age of participants was 61.5years (SD10.6) and the majority 63% (n = 47) were female. Participant mean disease duration was 17.8years (SD10.9). Mean SB time was 533.7 (SD100.1) minutes (8.9 hours per day/59.9% of waking hours). Mean sleep quality score was 7.2 (SD5.0) (Table 1). Correlation analysis and regression analysis found no significant correlation between sleep quality and SB variables. Regression analysis demonstrated positive statistical associations for SB time and body mass index (p-value=0.03846, R2 = 0.05143), SB time and pain VAS (p-value=0.009261, R2 = 0.07987), SB time and HADS (p-value = 0.009721, R2 = 0.08097) and SB time and HADSD (p-value = 0.01932, R2 = 0.0643).

Conclusion:

We found high levels of sedentary behavior and poor sleep quality in people who have RA, however no statistically significant relationship was found in this study. Future research should further explore the complex associations between sedentary behavior and sleep quality in people who have RA.

References:

[1]Carmona L, et al. Rheumatoid arthritis. Best Pract Res Clin Rheumatol 2010;24:733–745.

[2]Anon. Letter to the editor: standardized use of the terms “sedentary” and “sedentary behaviours”. Appl Physiol Nutr Metab = Physiol Appl Nutr Metab 2012;37:540–542.

[3]Fenton, S.A.M. et al. Sedentary behaviour is associated with increased long-term cardiovascular risk in patients with rheumatoid arthritis independently of moderate-to-vigorous physical activity. BMC Musculoskelet Disord 18, 131 (2017).

[4]McKenna S, et al. Sleep and physical activity: a cross-sectional objective profile of people with rheumatoid arthritis. Rheumatol Int. 2018 May;38(5):845-853.

[5]Grabovac, I., et al. 2018. Sleep quality in patients with rheumatoid arthritis and associations with pain, disability, disease duration, and activity. Journal of clinical medicine, 7(10)336.

Table 1.

Sleep quality in people who have RA

Sleep variableBed Time N(%) before 10pm13(18%) 10pm-12pm43 (60%) after 12pm16 (22%)Hours Sleep mean(SD)6.56 (1.54)Fall Asleep minutes mean(SD)33.3(27.7)Night Waking N(%)45(63%)Self-Rate Sleep mean(SD)2.74 (0.90)Hours Sleep mean(SD)6.56 (1.54)

Disclosure of Interests:

None declared

Molecular mechanisms for the antidepressant-like effects of a low-dose ketamine treatment in a DFP-based rat model for Gulf War Illness

Exposure to organophosphates (OP) during the First Gulf War is among one of the factors for Gulf War Illness (GWI) development in veterans and it has been challenging to treat GWI symptoms with existing therapies. Ketamine produces a rapid-onset and sustained antidepressant response, but there is no evidence whether ketamine treatment is effective for GWI depression. Repeated, low-dose exposure to diisopropyl fluorophosphate (DFP) mimic Gulf War related OP exposures and produces a chronic depressive state in rats. In this study, DFP-exposed rats treated with ketamine (10 mg/kg, i.p.) exhibited antidepressant-like effect on the Forced Swim Test at 1-h. This effect persisted at 24-h post ketamine, a time-point by which it is eliminated from the brain suggesting involvement of mechanisms that affect long-term synaptic plasticity. Western blot analysis showed significantly lower Brain-Derived Neurotrophic Factor (BDNF) levels in DFP rat brains. Ketamine produced a nonsignificant increase in BDNF expression at 1-h but produced a larger, significant (2.2-fold) increase at 24-h in DFP rats. We previously reported chronic hippocampal calcium elevations ([Ca2+]i) in DFP rats. Ketamine-treated DFP rats exhibited significantly lower [Ca2+]i at 1-h but not at 24-h. Interestingly, treatment with ANA-12, a TrkB-BDNF receptor antagonist, in DFP rats blunted ketamine's antidepressant-like effect at 24-h but not at 1-h. These experiments suggest that in a rat model of DFP-induced depression, inhibition of the NMDAR-Ca2+ contributes to the rapid-onset antidepressant effects of ketamine while the antidepressant actions that persisted at 24-h post ketamine administration involve upregulation of BDNF signaling.

Assessment of Ketamine and Its Enantiomers in an Organophosphate-Based Rat Model for Features of Gulf War Illness

Approximately 33% of U.S. soldiers from the first Gulf War suffer from a multi-system disorder known as the Gulf War Illness (GWI). GW veterans suffer from a cluster of symptoms that prominently include fatigue and can include mood-related symptoms. Compared to traditional antidepressants, ketamine (KET) produces a fast-onset and long-lasting antidepressant response, but assessments of KET for GWI-related depression are lacking. The etiology of GWI is multi-factorial and exposure to organophosphates (OP) during deployment is one of the factors underlying GWI development. Here, male Sprague-Dawley rats were repeatedly exposed to an OP DFP and three months later these rats, when assessed on a battery of rodent behavioral assays, displayed signs consistent with aspects of GWI characteristics. When treated with a sub-anesthetic dose of KET (3, 5, or 10 mg/kg, i.p.), DFP-treated rats exhibited a significant improvement in immobility time, open-arm exploration, and sucrose consumption as early as 1 h and much of these effects persisted at 24-h post-KET injection. KET's stereoisomers, R-KET and S-KET, also exhibited such effects in DFP rats, with R-KET being the more potent isomer. Our studies provide a starting point for further assessment of KET for GWI depression.

AB1349-HPR IMPLEMENTATION OF A GROUP EDUCATION SERVICE FOR RHEUMATOLOGY OUTPATIENTS COMMENCING BIOLOGIC THERAPY AT UNIVERSITY COLLEGE LONDON HOSPITAL (UCLH)

Background:

Biologic therapies are commonly prescribed in a range of rheumatic conditions. From 2016 - 2018, a mean of 226 rheumatology outpatients at UCLH commenced biologic therapy per year for inflammatory arthritis alone1. Patient education is required prior to initiation. At UCLH this is delivered via individual appointments with specialist nurses, contributing to waiting times for nurse appointments and thus delays in starting treatment.

Objectives:

1.To evaluate patient satisfaction following group education.

2.To reduce the burden on specialist nurses delivering multiple individual sessions.

Methods:

A once-weekly group education service was set up at UCLH. This comprised: an oral PowerPoint presentation; injection demonstration; question and answer session; and written leaflets. Patients were provided with pre- and post-session questionnaires to evaluate the service.

Results:

Over the first five weeks of the service, 18 patients attended group education (a median of 4 patients per session). Nine patients (50%) had previously researched the medication via internet search engines. Patients’ questions prior to the session were most commonly centred on side effects and long-term risks. All of the patients (100%) felt that “most or all” of their questions were answered during the session. Patients gave their awareness of the reason for therapy a median score of 7/10 pre-education; this rose to a median of 10/10 post-education. The median score given for confidence to self-administer the drug was 5.5/10 pre-education; this rose to a median of 10/10 post-education. The median anxiety score was 3/5 pre-education; this dropped to 2/5 post-education. The presentation was adapted based on questions that arose during the sessions. Multiple patients gave informal, verbal feedback stating that they found the group environment to be beneficial, providing a chance to meet others with similar conditions, share experiences and feel reassured that they are not alone in starting biologic therapy.

Conclusion:

Patient feedback demonstrated that the group education sessions at UCLH were effective in improving their understanding of the rationale for biologic treatment, increasing their confidence in self-administration, and reducing anxiety. Verbal feedback illustrated that many patients enjoyed the group environment, and the opportunity to interact and share experiences with others. At an average rate of 4 patients currently being seen a week, it is estimated that this will save 192 specialist nurse appointments per year (out of an estimated 226 commencing biologic therapy). There is scope for further research into the effects that this has had on waiting times to receive education / start treatment, and on drug compliance.

References:

[1]Greenwood, Mandy. UCLH Rheumatology Database. UCLH, 2020.

Disclosure of Interests:

None declared

Correction: Synergistic interactions between PLK1 and HDAC inhibitors in non-Hodgkin's lymphoma cells occur in vitro and in vivo and proceed through multiple mechanisms

[This corrects the article DOI: 10.18632/oncotarget.15649.].

Homoharringtonine interacts synergistically with bortezomib in NHL cells through MCL-1 and NOXA-dependent mechanisms

Background

Interactions between the protein synthesis inhibitor homoharringtonine (HHT) and the proteasome inhibitor bortezomib were investigated in DLBCL and mantle cell lymphoma cells (MCL).

Methods

Various DLBCL and MCL cells were exposed to HHT and bortezomib alone or together after which apoptosis and signaling pathway perturbations were monitored by flow cytometry and Western blot analysis. Xenograft mouse models were used to assess tumor growth and animal survival.

Results

HHT and bortezomib co-administration synergistically induced apoptosis in GC-, ABC- and double-hit DLBCL cells. Similar interactions were observed in MCL cells and in primary lymphoma cells. HHT/bortezomib co-administration diminished binding of MCL-1 to both BAK and NOXA. Knock-down of NOXA significantly diminished lethality whereas MCL-1 knock-down or ectopic NOXA expression increased cell death. Notably, HHT/bortezomib lethality was dramatically reduced in BAK knockout or knockdown cells. Finally, HHT/bortezomib co-administration significantly improved survival compared to single agents in GC- and ABC- xenograft models while exhibiting little toxicity.

Conclusions

These findings indicate that HHT and bortezomib cooperate to kill DLBCL and MCL cells through a process involving MCL-1 down-regulation, NOXA up-regulation, and BAK activation. They also suggest that a strategy combining HHT with bortezomib warrants attention in DLBCL and MCL.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-5018-x) contains supplementary material, which is available to authorized users.

Cotargeting BCL-2 and PI3K Induces BAX-Dependent Mitochondrial Apoptosis in AML Cells

Inhibitors targeting BCL-2 apoptotic proteins have significant potential for the treatment of acute myeloid leukemia (AML); however, complete responses are observed in only 20% of patients, suggesting that targeting BCL-2 alone is insufficient to yield durable responses. Here, we assessed the efficacy of coadministration of the PI3K/mTOR inhibitor GDC-0980 or the p110β-sparing PI3K inhibitor taselisib with the selective BCL-2 antagonist venetoclax in AML cells. Tetracycline-inducible downregulation of BCL-2 significantly sensitized MV4-11 and MOLM-13 AML cells to PI3K inhibition. Venetoclax/GDC-0980 coadministration induced rapid and pronounced BAX mitochondrial translocation, cytochrome c release, and apoptosis in various AML cell lines in association with AKT/mTOR inactivation and MCL-1 downregulation; ectopic expression of MCL-1 significantly protected cells from this regimen. Combined treatment was also effective against primary AML blasts from 17 patients, including those bearing various genetic abnormalities. Venetoclax/GDC-0980 markedly induced apoptosis in primitive CD34⁺/38^-/123⁺ AML cell populations but not in normal hematopoietic progenitor CD34⁺ cells. The regimen was also active against AML cells displaying intrinsic or acquired venetoclax resistance or tumor microenvironment-associated resistance. Either combinatorial treatment markedly reduced AML growth and prolonged survival in a systemic AML xenograft mouse model and diminished AML growth in two patient-derived xenograft models. Venetoclax/GDC-0980 activity was partially diminished in BAK^-/- cells and failed to induce apoptosis in BAX^-/- and BAX^-/-BAK^-/- cells, whereas BIM^-/- cells were fully sensitive. Similar results were observed with venetoclax alone in in vitro and in vivo systemic xenograft models. Collectively, these studies demonstrate that venetoclax/GDC-0980 exhibits potent anti-AML activity primarily through BAX and, to a lesser extent, BAK. These findings argue that dual BCL-2 and PI3K inhibition warrants further evaluation in AML.Significance: Combined treatment with clinically relevant PI3K and BCL-2 inhibitors may prove effective in the treatment of acute myeloid leukemia. Cancer Res; 78(11); 3075-86. ©2018 AACR.

Abstract 2018: Synergistic interactions between PLK1 and HDAC inhibitors in non-Hodgkin’s lymphoma cells occur in vitro and in vivo and proceed through multiple mechanisms

The mitotic kinase polo-like kinase 1 (PLK1) is over-expressed in neoplastic cells, including non-Hodgkin’s lymphoma (NHL) cells, but not in normal cells, prompting development of PLK1 inhibitors e.g., volasertib (Boehringer-Ingelheim). PLK1 plays key roles in cell cycle progression, mitosis, cytokinesis, centriole duplication, and the DNA damage response (DDR). Notably, volasertib demonstrated preliminary signs of activity in NHL patients in a phase I trial. HDAC inhibitors (HDACIs) modify chromatin structure and gene expression, but also induce multiple mitotic abnormalities including mitotic slippage and DNA damage checkpoint disruption. Given these complementary mechanisms, we sought to examine volasertib interactions with the pan-HDACI belinostat (Spectrum Pharmaceuticals) in diffuse large B-cell lymphoma (DLBCL) and mantle cell lymphoma (MCL) cells in vitro and in vivo. Exposure of DLBCL cells to extremely low (e.g., 5-30 nM), minimally toxic concentrations of volasertib and low (e.g., 100-400 nM), marginally toxic belinostat concentrations for 48 hr synergistically increased apoptosis in SU-DHL16, SU-DHL4, SU-DHL8 (GC subtype), HBL-1, U2932 (ABC-subtype), and OCI-LY18, Carnaval (double hit) DLBCL cells. Similar interactions occurred in primary lymphoma cells, Granta-519 and Rec-1 (MCL), SU-DHL4/BR and SU-DHL16/BR (bortezomib-resistant cells exhibiting up-regulation of the proteasome sub-unit PSMB5 and bortezomib binding site mutation (Ala49Val). In contrast, identical regimens were minimally toxic to normal hematopoietic progenitors. Volasertib/belinostat induced massive M-phase arrest, p-histone H3 up-regulation, a marked increase in mitotic errors, and pronounced M-phase cell death associated with striking DNA damage (γH2A.X formation). Belinostat diminished c-Myc mRNA and protein in DLBCL cells, an effect significantly enhanced by volasertib. Notably, PLK1 knock-down in DLBCL cells significantly increased belinostat-induced M-phase accumulation, phospho-histone H3 accumulation, γH2AX generation, and apoptosis. Analogously, c-Myc knock-down increased DNA damage and apoptosis in response to volasertib, arguing that c-Myc down-regulation plays a functional role in lethality. Volasertib/belinostat co-administration dramatically reduced tumor growth in an ABC-DLBCL flank model (U2932) and significantly increased survival (56.2 vs 39.7 days; p < 0.001) without weight loss or other toxicities. The regimen also enhanced survival and reduced tumor cell bone marrow engraftment in a systemic double-hit lymphoma model (OCI-Ly18). Together, these findings indicate that PLK1/HDAC inhibition warrants attention as a therapeutic strategy in NHL. Accordingly, based on these findings, a phase I volasertib/belinostat trial in patients with aggressive NHL is planned (NCT02875002).

Citation Format: Tri Nguyen, Rebecca Parker, Elisa Hawkins, Victor Yazbeck, Akhil Kolluri, Maciej Kmieciak, Mohamed Rahmani, Steven Grant. Synergistic interactions between PLK1 and HDAC inhibitors in non-Hodgkin’s lymphoma cells occur in vitro and in vivo and proceed through multiple mechanisms [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2018. doi:10.1158/1538-7445.AM2017-2018

Synergistic interactions between PLK1 and HDAC inhibitors in non-Hodgkin's lymphoma cells occur in vitro and in vivo and proceed through multiple mechanisms

Interactions between the polo-like kinase 1 (PLK1) inhibitor volasertib and the histone deacetylase inhibitor (HDACI) belinostat were examined in diffuse large B-cell lymphoma (DLBCL) and mantle cell lymphoma (MCL) cells in vitro and in vivo. Exposure of DLBCL cells to very low concentrations of volasertib in combination with belinostat synergistically increased cell death (apoptosis). Similar interactions occurred in GC-, ABC-, double-hit DLBCL cells, MCL cells, bortezomib-resistant cells and primary lymphoma cells. Co-exposure to volasertib/belinostat induced a marked increase in M-phase arrest, phospho-histone H3, mitotic errors, cell death in M-phase, and DNA damage. Belinostat diminished c-Myc mRNA and protein expression, an effect significantly enhanced by volasertib co-exposure. c-Myc knock-down increased DNA damage and cell death in response to volasertib, arguing that c-Myc down-regulation plays a functional role in the lethality of this regimen. Notably, PLK1 knock-down in DLBCL cells significantly increased belinostat-induced M-phase accumulation, phospho-histone H3, γH2AX, and cell death. Co-administration of volasertib and belinostat dramatically reduced tumor growth in an ABC-DLBCL flank model (U2932) and a systemic double-hit lymphoma model (OCI-Ly18), accompanied by a pronounced increase in survival without significant weight loss or other toxicities. Together, these findings indicate that PLK1/HDAC inhibition warrants attention as a therapeutic strategy in NHL.

Co-administration of the mTORC1/TORC2 inhibitor INK128 and the Bcl-2/Bcl-xL antagonist ABT-737 kills human myeloid leukemia cells through Mcl-1 down-regulation and AKT inactivation

Effects of concurrent inhibition of mTORC1/2 and Bcl-2/Bcl-xL in human acute myeloid leukemia cells were examined. Tetracycline-inducible Bcl-2/Bcl-xL dual knockdown markedly sensitized acute myeloid leukemia cells to the dual TORC1/2 inhibitor INK128 in vitro as well as in vivo. Moreover, INK128 co-administered with the Bcl-2/xL antagonist ABT-737 sharply induced cell death in multiple acute myeloid leukemia cell lines, including TKI-resistant FLT3-ITD mutants and primary acute myeloid leukemia blasts carrying various genetic aberrations e.g., FLT3, IDH2, NPM1, and Kras, while exerting minimal toxicity toward normal hematopoietic CD34(+) cells. Combined treatment was particularly active against CD34(+)/CD38(-)/CD123(+) primitive leukemic progenitor cells. The INK128/ABT-737 regimen was also effective in the presence of a protective stromal microenvironment. Notably, INK128 was more potent than the TORC1 inhibitor rapamycin in down-regulating Mcl-1, diminishing AKT and 4EBP1 phosphorylation, and potentiating ABT-737 activity. Mcl-1 ectopic expression dramatically attenuated INK128/ABT-737 lethality, indicating an important functional role for Mcl-1 down-regulation in INK128/ABT-737 actions. Immunoprecipitation analysis revealed that combined treatment markedly diminished Bax, Bak, and Bim binding to all major anti-apoptotic Bcl-2 members (Bcl-2/Bcl-xL/Mcl-1), while Bax/Bak knockdown reduced cell death. Finally, INK128/ABT-737 co-administration sharply attenuated leukemia growth and significantly prolonged survival in a systemic acute myeloid leukemia xenograft model. Analysis of subcutaneous acute myeloid leukemia-derived tumors revealed significant decrease in 4EBP1 phosphorylation and Mcl-1 protein level, consistent with results obtained in vitro. These findings demonstrate that co-administration of dual mTORC1/mTORC2 inhibitors and BH3-mimetics exhibits potent anti-leukemic activity in vitro and in vivo, arguing that this strategy warrants attention in acute myeloid leukemia.

A Tutorial on Target-Mediated Drug Disposition (TMDD) Models

Target-mediated drug disposition (TMDD) is the phenomenon in which a drug binds with high affinity to its pharmacological target site (such as a receptor) to such an extent that this affects its pharmacokinetic characteristics.1 The aim of this Tutorial is to provide an introductory guide to the mathematical aspects of TMDD models for pharmaceutical researchers. Examples of Berkeley Madonna2 code for some models discussed in this Tutorial are provided in the Supplementary Materials.

Pharmacokinetics of tenofovir during pregnancy and postpartum

OBJECTIVES

Tenofovir disoproxil fumarate (TDF) is increasingly used in the highly active antiretroviral therapy (HAART) regimens of pregnant women, but limited data exist on the pregnancy pharmacokinetics of chronically dosed TDF. This study described tenofovir pharmacokinetics during pregnancy and postpartum.

METHODS

International Maternal Pediatric and Adolescent AIDS Clinical Trials (IMPAACT) P1026s is a prospective, nonblinded pharmacokinetic study of HIV-infected pregnant women that included a cohort receiving 300 mg TDF once daily. Steady-state 24-hour pharmacokinetic profiles were measured at the second and third trimesters, postpartum, and in maternal and umbilical cord samples collected at delivery. Tenofovir was measured by liquid chromatography-mass spectrometry (LC-MS). The target area under the concentration versus time curve from time 0 to 24 h post dose (AUC) was ≥ 1.99 μg h/mL (nonpregnant historical control 10th percentile).

RESULTS

The median tenofovir AUC was decreased during the second (1.9 μg h/mL) and third (2.4 μg h/mL; P = 0.005) trimesters versus postpartum (3.0 μg h/mL). Tenofovir AUC exceeded the target for two of four women (50%) in the second trimester, 27 of 37 women [73%; 95% confidence interval (CI) 56%, 86%] in the third trimester, and 27 of 32 women (84%; 95% CI 67%, 95%) postpartum (P > 0.05). Median second/third-trimester troughs were lower (39/54 ng/mL) than postpartum (61 ng/mL). Median third-trimester weight was greater for subjects below the target AUC versus those above the target (97.9 versus 74.2 kg, respectively; P = 0.006). The median ratio of cord blood to maternal concentrations was 0.88. No infants were HIV infected.

CONCLUSIONS

This study found lower tenofovir AUC and troughs during pregnancy. Transplacental passage with chronic TDF use during pregnancy was high. Standard TDF doses appear to be appropriate for most HIV-infected pregnant women but therapeutic drug monitoring with dose adjustment should be considered in pregnant women with high weight (> 90 kg) or inadequate HIV RNA response.

Plasma sphingolipids are biomarkers of metabolic syndrome in non-human primates maintained on a Western-style diet

BACKGROUND

The intake of a Western diet enriched in animal fat has been shown to be a major risk factor for Type 2 diabetes and obesity. Previous rodent studies have indicated that these conditions may be triggered by the accumulation of the sphingolipid ceramide in insulin-sensitive tissues. However, data are lacking in this regard from both humans and non-human primates.

OBJECTIVE

Here we have investigated the relationship between plasma ceramides and metabolic syndrome in Rhesus macaques fed a high-fat and high-fructose (HFFD) 'western' diet.

METHODS

We investigated this relationship in cohorts of monkeys fed a HFFD for a period of 8 months to 5 years. Animals were classified as control, pre-diabetic or diabetic based on fasting plasma parameters and insulin sensitivity.

RESULTS

HFFD treatment produced significant increases in body weight and body fat and also resulted in a decline in insulin sensitivity. In parallel to the reduction in insulin sensitivity, significant increases in both plasma ceramide and dihydroceramide levels were observed, which further increased as animals progressed to the diabetic state. Plasma levels of the rare sphingolipid C18:0 deoxysphinganine, a marker of increased metabolic flux through serine palmitoyl transferase (SPT), were also elevated in both pre- and diabetic animals. Furthermore, plasma serine levels were significantly elevated in diabetic monkeys, which may indicate a shift in SPT substrate selectivity from serine to alanine or glycine. In contrast, branch chain amino acids were unchanged in pre-diabetic non-human primates, and only plasma valine levels were elevated in diabetic animals.

CONCLUSION

Together, these data indicate that HFFD induces de novo synthesis of ceramides in non-human primates, and that increased production of plasma ceramides is significantly correlated with the decline in insulin sensitivity.

Loss to follow-up among infants in a study of isoniazid prophylaxis (P1041) in South Africa

OBJECTIVE

To assess risk factors for loss to follow-up (LFU) from the IMPAACT P1041 study, an isoniazid (INH) prophylaxis study conducted in southern Africa.

DESIGN

Infants in two cohorts, human immunodeficiency virus-infected (HIV+) and HIV-exposed but non-infected (HIV-), were randomized to INH or placebo for 96 weeks. LFU was evaluated at week 96.

RESULTS

Of 1351 infants, 12.9% were LFU (10.4% HIV+, 14.7% HIV-); 65% of the HIV+ cohort was asymptomatic. Among HIV+ infants, large household size (>6 vs. <4 members, P = 0.035) and presence of an elder (≥55 years, P = 0.05) were associated with better retention. Although attenuated in adjusted analysis, these associations held among HIV- infants. Among HIV- infants, having a younger mother increased the risk (P = 0.008) and maternal history of TB reduced the risk of LFU, the latter by nearly 70% (P = 0.048 univariate, 0.09 adjusted). LFU was largely due to inability to contact the participant (58% HIV+, 30% HIV-), and inability to attend the clinic and withdrawal of consent (HIV-).

CONCLUSIONS

Household support was an important factor in participant retention, particularly for the non-HIV-infected cohort, as young maternal age was a risk factor for LFU. Retaining study participants from this mobile population can be challenging and may warrant additional support.

Malignant retroperitoneal and abdominal germ cell tumors: an intergroup study

BACKGROUND/PURPOSE

This randomized study examined survival (S) and event-free survival (EFS) rates using high-or standard-dose cisplatin-based combination chemotherapy and surgical resection for this subset of germ cell tumors.

METHODS

Twenty-six of 317 patients enrolled on the POG 9049/COG 8882 intergroup study for malignant germ cell tumors had abdomen or retroperitoneum as the primary site. Twenty-five of 26 were eligible for inclusion (n = 25). Patients had biopsy or resection at diagnosis and randomization to chemotherapy including etoposide, bleomycin, and either standard-dose (PEB) or high-dose cisplatin (HDPEB). In patients with initial biopsy, delayed resection was planned.

RESULTS

Median age was 26 months. There were 14 girls and 11 boys. There were 3 stage I to II, 5 stage III, and 17 stage IV patients. Surgical management included primary resection in 5, resection after chemotherapy in 13, and biopsy or partial resection in 7 patients. Overall 6-year EFS rate was 82.8% +/- 10.9%, and 6-year survival rate was 87.6% +/- 9.3%. By group, 6-year survival rate was 90.0% +/- 11.6% for PEB and 85.7 +/- 14.5% for HDPEB. Deaths include one from sepsis, one from malignant tumor progression, and one from bulky disease caused by benign components despite response of the malignant elements to chemotherapy.

CONCLUSIONS

Malignant germ cell tumors arising in the abdomen and retroperitoneum have an excellent prognosis despite advanced stage in most children. Aggressive resection need not be undertaken at diagnosis, but a concerted attempt at complete surgical removal after chemotherapy is important to distinguish viable tumor from necrotic tumor or benign elements that will not benefit from further chemotherapy.

Long-term follow-up of bone mass after orthotopic liver transplantation: effect of steroid withdrawal from the immunosuppressive regimen

Glucocorticoids have been suggested to play a major role in transplantation-related osteopenia. In this study we assess the long-term changes and the effect of steroid withdrawal from the standard immunosuppressive regimen on bone mineral density (BMD) after orthotopic liver transplantation (OLT). Sixty-nine non-osteoporotic patients (20 women, 49 men), aged 48 +/- 9.5 years (mean +/- SD), and with a follow-up of 58.3 +/- 23.2 months (range 24-121 months) were studied. Immunosuppressive treatment consisted of prednisone, cyclosporin A and azathioprine. In 41 patients (group A), prednisone was tapered and withdrawn after 36.2 +/- 19.3 months (range 13-79 months), whereas in 28 patients (group B) prednisone was maintained. BMD in the spine (L1-L4) was serially measured by dual-energy X-ray absorptiometry (Hologic QDR 1,000w) at baseline, before steroid withdrawal and at the end of study. Age- and sex-matched Z-scores of BMD were calculated. No differences were found in age, body mass index, time since OLT, or baseline BMD between the two groups. BMD had significantly increased in both groups at the end of follow-up period (group A, +8.1 +/- 8.7%; group B, +3.2 +/- 8.0%, p < 0.05). However, the Z-score was significantly higher in group A than in group B at the end of study (-0.44 +/- 1.05 vs -0.99 +/- 0.77; p<0.05). BMD recovery was lower in pre-OLT biliary cirrhosis patients. Bone mass improvement was independent of the time since OLT in both groups, and of the time of steroid withdrawal in group A. Our data confirm that steroid withdrawal accelerates the recovery of bone mass in patients who have undergone a successful liver transplantation.

Validation and development of fluorescence two-dimensional differential gel electrophoresis proteomics technology

Fluorescence two-dimensional differential gel electrophoresis (2-D DIGE*) is a new development in protein detection for two-dimensional gels. Using mouse liver homogenates (control and paracetamol (N-acetyl-p-aminophenol, APAP)-treated), we have determined the quantitative variation in the 2-D DIGE process and established statistically valid thresholds for assigning quantitative changes between samples. Thresholds were dependent on normalised spot volume, ranged from approximately 1.2 fold for large volume spots to 3.5 fold for small volume spots and were not markedly affected by the particular cyanine dye combination or by multiple operators carrying out the dye labelling reaction. To minimise the thresholds, substantial user editing was required when using ImageMaster 2D-Elite software. The difference thresholds were applied to the test system and quantitative protein differences were determined using replicate gels of pool samples and single gels from multiple individual animals (control vs treated in each gel). Throughout, the differences revealed with a particular cyanine dye combination were mirrored almost without exception when the dye combination was reversed. Both pool and individual sample analyses provided unique data to the study. The inter-animal response variability in inbred mice was approximately nine times that contributed by the 2-D DIGE process. A number of the most frequently observed protein changes resulting from APAP-treatment were identified by mass spectrometry. Several of these can be rationalised based on available data on the mechanism of APAP hepatotoxicity but others cannot, indicating that proteomics can provide further insights into the biochemical basis of APAP toxicity.

The landing of the NEAR-Shoemaker spacecraft on asteroid 433 Eros

The NEAR-Shoemaker spacecraft was designed to provide a comprehensive characterization of the S-type asteroid 433 Eros (refs 1,2,3), an irregularly shaped body with approximate dimensions of 34 x 13 x 13 km. Following the completion of its year-long investigation, the mission was terminated with a controlled descent to its surface, in order to provide extremely high resolution images. Here we report the results of the descent on 12 February 2001, during which 70 images were obtained. The landing area is marked by a paucity of small craters and an abundance of 'ejecta blocks'. The properties and distribution of ejecta blocks are discussed in a companion paper. The last sequence of images reveals a transition from the blocky surface to a smooth area, which we interpret as a 'pond'. Properties of the 'ponds' are discussed in a second companion paper. The closest image, from an altitude of 129 m, shows the interior of a 100-m-diameter crater at 1-cm resolution.

Proteinuria and perinatal lethality in mice lacking NEPH1, a novel protein with homology to NEPHRIN

A high-throughput, retrovirus-mediated mutagenesis method based on gene trapping in embryonic stem cells was used to identify a novel mouse gene. The human ortholog encodes a transmembrane protein containing five extracellular immunoglobulin-like domains that is structurally related to human NEPHRIN, a protein associated with congenital nephrotic syndrome. Northern analysis revealed wide expression in humans and mice, with highest expression in kidney. Based on similarity to NEPHRIN and abundant expression in kidney, this protein was designated NEPH1 and embryonic stem cells containing the retroviral insertion in the Neph1 locus were used to generate mutant mice. Analysis of kidney RNA from Neph1(-/-) mice showed that the retroviral insertion disrupted expression of Neph1 transcripts. Neph1(-/-) pups were represented at the expected normal Mendelian ratios at 1 to 3 days of age but at only 10% of the expected frequency at 10 to 12 days after birth, suggesting an early postnatal lethality. The Neph1(-/-) animals that survived beyond the first week of life were sickly and small but without edema, and all died between 3 and 8 weeks of age. Proteinuria ranging from 300 to 2,000 mg/dl was present in all Neph1(-/-) mice. Electron microscopy demonstrated NEPH1 expression in glomerular podocytes and revealed effacement of podocyte foot processes in Neph1(-/-) mice. These findings suggest that NEPH1, like NEPHRIN, may play an important role in maintaining the structure of the filtration barrier that prevents proteins from freely entering the glomerular urinary space.

Surgery for ovarian masses in infants, children, and adolescents: 102 consecutive patients treated in a 15-year period

BACKGROUND/PURPOSE

Ovarian pathology, although rare in children, must be included in the differential diagnosis of all girls who present with abdominal pain, an abdominal mass, or precocious puberty.

METHODS

To improve clinical appreciation of these lesions, the authors reviewed the presentation, evaluation, and outcome of all patients with ovarian pathology surgically treated at their institution since 1985.

RESULTS

One hundred two girls (aged 9.8 +/- 5.5 years; range, 2 days to 20 years) underwent 106 separate ovarian operations (43 salpingo-oophorectomies, 21 oophorectomies, 33 ovarian cystectomies, and 9 ovarian biopsies). Of those presenting with acute abdominal pain (n = 59), 25 (42%) had ovarian torsion (14 associated with a mature teratoma), and only 1 (2%) had a malignant tumor. In contrast, of those presenting with an abdominal mass (n = 23), 6 (26%) had malignancies. There was no age difference between those with benign disease (9.9 +/- 5.6 years; n = 96) and those with malignant tumors (8.6 +/- 3.9 years, n = 10). Nine children had 10 operations for presumed malignant tumors (3 dysgerminomas, 2 immature teratomas with foci of yolk sac tumor, 2 juvenile granulosa cell tumors, 1 yolk sac tumor, and 1 Sertoli-Leydig cell tumor). These patients all had unilateral salpingo-oophorectomy, 4 had chemotherapy, and all are now disease free at 8.4 +/- 4.1 years follow-up.

CONCLUSION

Ovarian pathology remains a rare indication for surgery in girls less than 20 years of age. Because most of these lesions are benign, ovarian-preserving operations should be performed whenever feasible.

Imaging of small-scale features on 433 Eros from NEAR: evidence for a complex regolith

On 25 October 2000, the Near Earth Asteroid Rendevous (NEAR)-Shoemaker spacecraft executed a low-altitude flyover of asteroid 433 Eros, making it possible to image the surface at a resolution of about 1 meter per pixel. The images reveal an evolved surface distinguished by an abundance of ejecta blocks, a dearth of small craters, and smooth material infilling some topographic lows. The subdued appearance of craters of different diameters and the variety of blocks and different degrees of their burial suggest that ejecta from several impact events blanketed the region imaged at closest approach and led to the building up of a substantial and complex regolith consisting of fine materials and abundant meter-sized blocks.

Safety of 2 recombinant human immunodeficiency virus type 1 (HIV-1) envelope vaccines in neonates born to HIV-1-infected women

To determine the safety of 2 candidate vaccines against human immunodeficiency virus type 1 (HIV-1), a randomized, placebo-controlled, multicenter trial compared low, medium, and high doses of the vaccines or an adjuvant among infants born to HIV-infected women. No local or systemic reactions of grade 2 or greater were reported 48 h after the subjects underwent immunization. Grade 3 or 4 chemistry toxicities occurred in 5 (3%) and grade 3 or 4 hematologic toxicities in 17 (11%) of 154 vaccinated subjects (not significantly different from 29 adjuvant recipients). CD4(+) cell percentages of < or = 20% occurred at least once in 9 vaccinated subjects and 1 control subject. Sustained CD4(+) cell percentages of < or = 20% occurred in 4 HIV-infected children. Fourteen infants (8%) were confirmed to be HIV-infected; median CD4(+) cell counts among these children were 2074, 1674, 1584, and 821 cells/mm(3) at birth and weeks 24, 52, and 104, respectively. Thus, both vaccines were safe and well tolerated in neonates, and there was no evidence of accelerated immunologic decline in HIV-infected infants.

Validation and development of fluorescence two-dimensional differential gel electrophoresis proteomics technology

Fluorescence two-dimensional differential gel electrophoresis (2-D DIGE*) is a new development in protein detection for two-dimensional gels. Using mouse liver homogenates (control and paracetamol (N-acetyl-p-aminophenol, APAP)-treated), we have determined the quantitative variation in the 2-D DIGE process and established statistically valid thresholds for assigning quantitative changes between samples. Thresholds were dependent on normalised spot volume, ranged from approximately 1.2 fold for large volume spots to 3.5 fold for small volume spots and were not markedly affected by the particular cyanine dye combination or by multiple operators carrying out the dye labelling reaction. To minimise the thresholds, substantial user editing was required when using ImageMaster 2D-Elite software. The difference thresholds were applied to the test system and quantitative protein differences were determined using replicate gels of pool samples and single gels from multiple individual animals (control vs treated in each gel). Throughout, the differences revealed with a particular cyanine dye combination were mirrored almost without exception when the dye combination was reversed. Both pool and individual sample analyses provided unique data to the study. The inter-animal response variability in inbred mice was approximately nine times that contributed by the 2-D DIGE process. A number of the most frequently observed protein changes resulting from APAP-treatment were identified by mass spectrometry. Several of these can be rationalised based on available data on the mechanism of APAP hepatotoxicity but others cannot, indicating that proteomics can provide further insights into the biochemical basis of APAP toxicity.

Malignant mediastinal germ cell tumors: an intergroup study

PURPOSE

This review was conducted to determine clinical characteristics and response to therapy in this rare pediatric neoplasm.

METHODS

An intergroup Pediatric Oncology Group (POG) 9049/Children's Cancer Study Group (CCG) 8882 randomized trial was conducted to evaluate response rate and survival with chemotherapy using etoposide, bleomycin, and high or standard dose cisplatin for high-risk malignant germ cell tumors at extragonadal sites. For this review, a secondary analysis of clinical and operative findings in patients with primary site in the mediastinum was carried out.

RESULTS

Of the 38 children with malignant mediastinal germ cell tumors (MGCT), 36 had sufficient data to be included in this review. Thirty-four tumors were anterior mediastinal, 2 were intrapericardial. Younger patients had respiratory complaints; older patients had chest pain, precocious puberty, or facial fullness. Yolk sac tumor was the only malignant element in girls. Boys had yolk sac tumor in 7, germinoma in 3, choriocarcinoma in 2, and mixed malignant elements in 15. Benign teratoma elements coexisted in 22 patients. Four patients had biopsy and chemotherapy without tumor resection, and only 1 survived. Fourteen patients had resection at diagnosis followed by chemotherapy with 12 survivors. Eighteen patients had biopsy followed by chemotherapy and postchemotherapy tumor resection with 13 survivors. Tumor size in response to chemotherapy for these 18 patients was stable or increased in 6, and decreased in 12 (mean decrease of 57% in greatest dimension). Overall, 26 of 36 patients survived, with a 4-year patient survival rate of 71%+/-10%, and a 4-year event-free survival rate of 69%+/-10%. Ten patients died: 5 of tumor (all boys > or =15 yr), 2 of sepsis, and 3 of second malignancy.

CONCLUSIONS

Malignant MGCT is a complex tumor of varied histology with frequent coexistence of benign elements. Lesions often have incomplete regression with chemotherapy alone. Tumor resection may be undertaken at diagnosis or after attempted shrinkage with chemotherapy. Aggressive attempt at complete tumor resection should be offered to all patients even if bulky tumor persists after induction chemotherapy with expectation of a significant salvage rate. Boys > or =15 years may be a high-risk subgroup for mortality from tumor progression.

The effect of cisplatin dose and surgical resection in children with malignant germ cell tumors at the sacrococcygeal region: a pediatric intergroup trial (POG 9049/CCG 8882)

PURPOSE

This study was designed to evaluate (1) the efficacy of standard or high-dose cisplatin with etoposide and bleomycin and (2) the role of surgical resection in infants and children with malignant germ cell tumors of the sacrococcygeal region (SCT).

METHODS

Seventy-four of 317 children presenting to Pediatric Oncology Group (POG)/Children's Cancer Group (CCG) institutions from 1990 through 1996 with malignant germ cell tumors had malignant SCT. There were 62 girls and 12 boys with a median age of 21 months (range, 3 days to 37 months) and median serum alpha-fetoprotein of 35,500 ng/mL. Twelve had undergone resection of a benign SCT as a newborn. Forty-four (59%) had evidence of metastatic disease at time of diagnosis. Presentation by type (Altman classification) was I, 0; II, 2; III, 30; and IV, 42. The initial procedure was biopsy in 45 and resection in 29. Patients were assigned randomly to receive 4 cycles of chemotherapy with etoposide (E) and bleomycin (B) and either high-dose cisplatin (200 mg/m(2) per cycle; HDP) or standard dose cisplatin (100 mg/m(2) per cycle; P). After completion of chemotherapy, 42 of 45 initially treated with biopsy underwent resection.

RESULTS

Overall 4-year survival rate is 90% (SE = 4%) and 4-year event-free survival (EFS) is 84% (SE = 6%). Event-free survival data for subgroups of interest are as follows: 4-yr EFS% (SE) P Values Mets (44) 88 (6).48 No Mets (30) 80 (8) HDP EB (37) 89 (6).21 P EB (37) 78 (7) Initial Resection (29) 90 (7).50 Delayed Resection (42) 83 (7) Complete Resection (49) 90 (5).19 CR/PR Partial Resection (22) 77 (10) Biopsy Only (3) 33 (27).005 (3 way)

CONCLUSIONS

(1) The current survival rate of malignant sacrococcygeal tumors is excellent even with metastases. (2) Delayed surgical resection is not associated with an adverse outcome. (3) In this subset the treatment comparison was inconclusive however, followed the trend in the overall study of more than 300 children in which the high-dose cisplatin group had superior EFS (P<.05).

NEAR at eros: imaging and spectral results

Eros is a very elongated (34 kilometers by 11 kilometers by 11 kilometers) asteroid, most of the surface of which is saturated with craters smaller than 1 kilometer in diameter. The largest crater is 5.5 kilometers across, but there is a 10-kilometer saddle-like depression with attributes of a large degraded crater. Surface lineations, both grooves and ridges, are prominent on Eros; some probably exploit planes of weakness produced by collisions on Eros and/or its parent body. Ejecta blocks (30 to 100 meters across) are abundant but not uniformly distributed over the surface. Albedo variations are restricted to the inner walls of certain craters and may be related to downslope movement of regolith. On scales of 200 meters to 1 kilometer, Eros is more bland in terms of color variations than Gaspra or Ida. Spectra (800 to 2500 nanometers) are consistent with an ordinary chondrite composition for which the measured mean density of 2.67 +/- 0.1 grams per cubic centimeter implies internal porosities ranging from about 10 to 30 percent.

Use of human immunodeficiency virus (HIV) human hyperimmune immunoglobulin in HIV type 1-infected children (Pediatric AIDS clinical trials group protocol 273)

The clinical, immunologic, and virologic effects and the pharmacokinetics of human immunodeficiency virus (HIV) human hyperimmune immunoglobulin (HIVIG) were assessed in 30 HIV-infected children aged 2-11 years. All had moderately advanced disease with an immune complex-dissociated (ICD) p24 antigen >70 pg/mL and were on stable antiviral therapy. Three groups of 10 children received 6 monthly infusions of 200, 400, or 800 mg/kg of HIVIG, and serial immunologic and virologic assays were performed. HIVIG doses as high as 800 mg/kg were safe and well tolerated. The half-life of HIVIG, determined by serial p24 antibody titers, was 13-16 days, the volume of distribution was 102-113 mL/kg, and clearance was 5.6-6.0 mL/kg/day. Plasma ICD p24 decreased during the infusions, but CD4 cell levels, plasma RNA copy number, cellular virus, immunoglobulin levels, and neutralizing antibody titers were minimally affected by the infusions. Clinical status did not change during the 6-month infusion and 3-month follow-up periods.

Surgical resection alone is effective treatment for ovarian immature teratoma in children and adolescents: a report of the pediatric oncology group and the children's cancer group

OBJECTIVE

In both adult women and children the potential for malignant recurrence from ovarian immature teratoma has prompted the standard use of chemotherapy after complete resection of the primary tumor. The efficacy of postoperative chemotherapy in children and adolescents with ovarian immature teratoma, however, has not been established. A pediatric intergroup trial (INT 0106) was designed to determine the need for postoperative chemotherapy in patients with ovarian immature teratoma after management with surgical resection only.

STUDY DESIGN

Between 1990 and 1995, 44 patients with completely resected ovarian immature tumor and without postoperative chemotherapy, who were able to undergo assessment, were accrued. Tumor tissue was evaluated by central pathology review to confirm diagnosis and determine tumor grading of immature neural elements. Patients were followed carefully for recurrence of disease with appropriate diagnostic imaging and serum marker studies.

RESULTS

Thirty-one patients had pure ovarian immature teratoma with a tumor grade of 1 (n = 17), 2 (n = 12), or 3 (n = 2). Age at diagnosis ranged between 1.5 and 15 years (median, 10). Of the 29 patients studied, the serum alpha-fetoprotein level was elevated in 10 (34%); the median level was 25 ng/ml. Thirteen patients had ovarian immature teratoma plus microscopic foci of yolk sac tumor. Tumor grade was 1, 2, or 3 in 1, 6, and 6 patients, respectively. Age ranged between 6 and 20 years (median, 12). In the 12 patients evaluated for serum alpha-fetoprotein, 10 (83%) had elevated levels; the median level was 262 ng/ml. The 4-year event-free and overall survival for the ovarian immature teratoma group and for the ovarian immature teratoma plus yolk sac tumor group was 97.7% (95% confidence interval, 84.9%-99.7%) and 100%, respectively. The only yolk sac tumor relapse occurred in a child with ovarian immature teratoma and yolk sac tumor who was then treated with chemotherapy and is alive and free of disease 57 months after recurrence.

CONCLUSION

The results of this study suggest that surgery alone is curative for most children and adolescents with resected ovarian immature teratoma of any grade, even when elevated levels of serum alpha-fetoprotein or microscopic foci of yolk sac tumor are present. This experience strongly supports avoiding the long-term effects of chemotherapy in most children with ovarian immature teratoma by reserving postoperative therapy for cases with relapse.

Imaging of asteroid 433 eros during NEAR's flyby reconnaissance

During the 23 December 1998 flyby of asteroid 433 Eros, the Near-Earth Asteroid Rendezvous (NEAR) spacecraft obtained 222 images of Eros, as well as supporting spectral observations. The images cover slightly more than two-thirds of Eros (best resolution is approximately 400 meters per pixel) and reveal an elongated, cratered body with a linear feature extending for at least 20 kilometers. Our observations show that Eros has dimensions of 33 x 13 x 13 kilometers. The volume, combined with the mass determined by the NEAR radio science experiment, leads to a density of 2.5 +/- 0.8 grams per cubic centimeter. This relatively high density, and the presence of an extensive linear feature, suggest that Eros may be a structurally coherent body.

Complete surgical excision is effective treatment for children with immature teratomas with or without malignant elements: A Pediatric Oncology Group/Children's Cancer Group Intergroup Study

PURPOSE

To determine whether the 3-year event-free survival (EFS) of children with completely resected immature teratomas is greater than 85%.

PATIENTS AND METHODS

Patients with immature teratomas treated at Pediatric Oncology Group or Children's Cancer Group institutions were eligible. Pathology was centrally reviewed to confirm diagnosis and tumor grading. Follow-up included physical examination, measurement of tumor markers (alpha fetoprotein and human chorionic gonadotropin), and imaging. All patients were monitored for events, defined as tumor recurrence, second malignancy, or death.

RESULTS

Seventy-three children (median age, 7.8 years) with extracranial immature teratomas were enrolled on study. Primary tumor sites included ovarian (n = 44), testicular (n = 7), and extragonadal (n = 22). However, on review, 23 patients had foci of yolk sac tumor (n = 21) or primitive neuroectodermal tumor (n = 2), whereas 50 had pure immature teratomas. Twenty-five patients had increased alpha fetoprotein (n = 18), human chorionic gonadotropin (n = 5), or both (n = 2); nine had foci of yolk sac tumor on review. Pathology review identified 23 patients with grade 1, 29 with grade 2, and 21 with grade 3 immature teratomas. With a median follow-up of 35 months, the overall 3-year EFS was 93% (95% confidence interval, 86% to 98%), with 3-year EFS of 97.8%, 100%, and 80% for patients with ovarian, testicular, and extragonadal tumors, respectively. Only four of 23 patients with immature teratoma and malignant foci developed recurrence, suggesting that surgical resection followed by close observation are effective treatment. Overall, five patients had disease recurrence 4 to 7 months from diagnosis, and four (80%) are disease free after platinum-based therapy. The fifth patient has residual tumor after cisplatin, etoposide, and bleomycin treatment requiring further therapy.

CONCLUSION

Surgical excision is safe and effective treatment for 80% to 100% of children with immature teratoma.

Safety and immunogenicity of HIV recombinant envelope vaccines in HIV-infected infants and children. National Institutes of Health-sponsored Pediatric AIDS Clinical Trials Group (ACTG-218)

Study objectives were to evaluate the safety and immunogenicity of three HIV recombinant glycoproteins in HIV-infected infants and children between 1 month and 18 years of age with asymptomatic (P-1) infection. Using Chiron rgp 120 (SF-2) 15 or 50 microg; MicroGeneSys rgp 160 (IIIB) 40 or 320 microg; Genentech rgp120 (MN) 75 or 300 microg; or adjuvant control (Alum or MF-59), children were randomized to a double-blind, placebo-controlled, dose-escalating study of vaccine administered intramuscularly at entry and 1, 2, 3, 4, and 6 months later. No adverse events were attributed to study vaccines. Between 30% and 56% of volunteers exhibited a lymphoproliferative response as defined in terms of stimulation index (SI) to vaccine antigens; 65% of vaccinees but none of placebo recipients exhibited moderate or strong responses after enzyme immunoassay to HIV specific antigens. CD4 cell counts and quantitative HIV culture did not differ significantly among vaccine and control groups, nor were differences found among groups in HIV disease progression. The rgp160 and gp120 subunit vaccines were safe and immunogenic in this population.