Analytical evaluation and critical appraisal of early commercial SARS-CoV-2 immunoassays for routine use in a diagnostic laboratory

Background: The objective of this study was to evaluate the performance characteristics of early commercial SARS-CoV-2 antibody assays in mild and asymptomatic subjects to enable the selection of suitable immunoassays for routine diagnostic use.

Methods: We used serum samples from a pre-COVID era patient cohort (n = 50, pre-December 2019), designated SARS-CoV-2 negative, and serum samples from a SARS-CoV-2 RT-PCR-positive cohort (n = 90) taken > 14 days post-symptom onset (April–May 2020). Six ELISA assays were evaluated, including one confirmation assay to investigate antibody specificity. We also evaluated one point-of-care lateral flow device (LFIA) and one high throughput electrochemiluminescence immunoassay (CLIA).

Results: The ELISA specificities ranged from 84% to 100%, with sensitivities ranging from 75.3% to 90.0%. The LFIA showed 100% specificity and 80% sensitivity using smaller sample numbers. The Roche CLIA immunoassay showed 100% specificity and 90.7% sensitivity. When used in conjunction, the Euroimmun nucleocapsid (NC) and spike-1 (S1) IgG ELISA assays had a sensitivity of 95.6%. The confirmation Dia.Pro IgG assay showed 92.6% of samples tested contained both NC and S1 antibodies, 32.7% had NC, S1 and S2 and 0% had either S1 or S2 only.

Conclusions: The Roche assay and the Euroimmun NC and S1 assays had the best sensitivity overall. Combining the assays detecting NC and S1/S2 antibody increased diagnostic yield. These first-generation assays were not calibrated against reference material and the results were reported qualitatively. A portfolio of next-generation SARS-CoV-2 immunoassays will be necessary to investigate herd and vaccine-induced immunity.

Abstract P2-06-07: Investigating the role of focal adhesion kinase in regulating CSC activity in invasive ductal carcinoma

Background

Breast Cancer Stem-like Cells (BCSCs) have been associated with tumour development, metastasis and recurrence1. Focal Adhesion Kinase (FAK) is a non-receptor tyrosine kinase classically known for its role in metastasis, proliferation and survival. We have previously shown FAK plays a role in regulating CSC activity in DCIS2. We aimed to investigate FAK and CSC marker expression in a retrospective patient cohort. We aimed to evaluate the effects of FAK inhibition on CSC activity in Invasive Ductal Carcinoma.

Methods

Using a retrospective case-control cohort of 244 patients across a range of molecular phenotypes we evaluated FAK Immunohistochemical expression alongside CSC markers; Aldehyde Dehydrogenase 1 (ALDH1) and Integrin Alpha 6 (ITGa6). FAK expression was measured in IDC cell lines and ALDEFLUOR high expressing cells. FAK was inhibited using 0.5μM VS4718 or SiRNA and CSC activity evaluated in 5 cell lines and 25 patient samples. We determined the effects of 50mg/kg VS4718 for 4 weeks as single agent or in combination with Paclitaxel 7.5mg/kg in a ER-/PR-/HER- Patient Derived Xenograft model (PDX).

Results

Total FAK expression was associated with reduced breast cancer survival. Co-expression of FAK and either BCSC marker was associated with the poorest survival.

FAK and CSC marker expression pFAKtFAKALDH1ITGα6tFAK and ALDH1tFAK and ITGα6Recurrence Risk0.58 (0.31-1.08) p = 0.0842.05 (1.23-3.43) p = 0.0062.21 (1.20-4.05) p=0.0111.54 (0.92-2.23) p=0.107  Breast Cancer Death0.41 (0.12-1.51) p=0.1824.84 (2.33 -10.04) p = <0.0016.58 (1.87-23.10) p=0.0032.23 (1.08-4.58) p=0.03016.7 (3.7-73.9) p=<0.00112.8 (1.37-13.2,) p=0.012Hazard ratios calculated using cox-proportional hazard regression analysis.

pFAK was higher in ALDEFLUOR expressing cells and triple negative cell lines. SiRNA knockout of FAK reduced mammosphere formation, self-renewal and ALDEFLUOR expression from 1.2% to 0.2% (p=<0.01, unpaired t-test) in MDA-MB-231 cells. VS4718 reduced primary mammosphere forming efficiency in all cell lines and reduced self-renewal in ER negative cell lines. FAK inhibition led to a reduction in mammosphere forming efficiency and self-renewal in 25 primary breast cancer specimens as outlined below:

FAK inhibition reduces MFE Primary Breast Cancer samples  ER negative cell lines   ER+/PR+/ Her2-ER-/PR-/Her2+ER-/PR-/Her2-SKBr3MDA-MB-231SUM159Primary mammosphere formation51.1% (n=17)53.2% (n=4)49.6% (n=5)74.1%84.8%67.6%Secondary mammosphere formation45.8% (n=8) 43.9% (n=3)42.1%57.9%47.5%Percentage of mammospheres formed given relative to control. Cell line work, minimum n=6. All above significant p=<0.05, One way Anova used with post hoc Tukeys test.

VS4718 reduced tumour growth, Ki67 staining and CSC activity in our triple negative PDX model. VS4718 administration reduced ex-vivo mammosphere formation, tumour initiating capacity and prevented ALDEFLUOR enrichment when used in combination with Paclitaxel.

Conclusions

FAK, ALDH1 and ITGa6 are associated with increased breast cancer mortality in early breast cancer. Inhibition of FAK reduces CSC activity in vitro and in vivo in cell lines and patient samples. This data suggest that FAK inhibition may be used to reduce CSC activity in triple negative carcinoma.

1. Williams et al, Stem cells 2015.

Citation Format: Timbrell S, Aglan H, Cramer A, Foden P, Weaver D, Pachter J, Farnie G, Clarke R, Bundred N. Investigating the role of focal adhesion kinase in regulating CSC activity in invasive ductal carcinoma [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-06-07.

Hypoxia in Combination With Muscle Contraction Improves Insulin Action and Glucose Metabolism in Human Skeletal Muscle via the HIF-1α Pathway

Skeletal muscle insulin resistance is the hallmark of type 2 diabetes and develops long before the onset of the disease. It is well accepted that physical activity improves glycemic control, but the knowledge on underlying mechanisms mediating the beneficial effects remains incomplete. Exercise is accompanied by a decrease in intramuscular oxygen levels, resulting in induction of HIF-1α. HIF-1α is a master regulator of gene expression and might play an important role in skeletal muscle function and metabolism. Here we show that HIF-1α is important for glucose metabolism and insulin action in skeletal muscle. By using a genome-wide gene expression profiling approach, we identified RAB20 and TXNIP as two novel exercise/HIF-1α-regulated genes in skeletal muscle. Loss of Rab20 impairs insulin-stimulated glucose uptake in human and mouse skeletal muscle by blocking the translocation of GLUT4 to the cell surface. In addition, exercise/HIF-1α downregulates the expression of TXNIP, a well-known negative regulator of insulin action. In conclusion, we are the first to demonstrate that HIF-1α is a key regulator of glucose metabolism in skeletal muscle by directly controlling the transcription of RAB20 and TXNIP These results hint toward a novel function of HIF-1α as a potential pharmacological target to improve skeletal muscle insulin sensitivity.

Adipocyte-derived factors impair insulin signaling in differentiated human vascular smooth muscle cells via the upregulation of miR-143

Cardiovascular complications are common in patients with type 2 diabetes. Adipokines have been implicated in the induction of proliferative and pro-atherogenic alterations in human vascular smooth muscle cells (hVSMC). Other reports demonstrated the importance of the miRNA cluster miR-143/145 in the regulation of VSMC homeostasis and insulin sensitivity. Here we investigated whether the detrimental effects of adipokines on hVSMC function could be ascribed to alterations in miR-143/145 expression. The exposure of hVSMC to conditioned media (CM) from primary human subcutaneous adipocytes increased the expression of smooth muscle α-actin (SMA), and the miR-143/145 cluster, but markedly impaired the insulin-mediated phosphorylation of Akt and its substrate endothelial nitric oxide synthase (eNOS). Furthermore, CM promoted the phosphorylation of SMAD2 and p38, which have both been linked to miR-143/145 induction. Accordingly, the induction of miR-143/145 as well as the inhibition of insulin-mediated Akt- and eNOS-phosphorylation was prevented when hVSMC were treated with pharmacological inhibitors for Alk-4/5/7 and p38 before the addition of CM. The transfection of hVSMC with precursor miR-143, but not with precursor miR-145, resulted in impaired insulin-mediated phosphorylation of Akt and eNOS. This inhibition of insulin signaling by CM and miR-143 is associated with a reduction in the expression of the oxysterol-binding protein-related protein 8 (ORP8). Finally, the knock-down of ORP8 resulted in impaired insulin-mediated phosphorylation of Akt in hVSMC. Thus, the detrimental effects of adipocyte-derived conditioned media on insulin action in primary hVSMC can be ascribed to the Alk- and p38-dependent induction of miR-143 and subsequent downregulation of ORP8.

Differential impact of oleate, palmitate, and adipokines on expression of NF-κB target genes in human vascular smooth muscle cells

It is widely accepted that obesity is a major risk factor for the development of atherosclerosis. In this context, adipose tissue produces a variety of adipokines and releases free fatty acids, contributing to a chronic-low grade inflammation state implicated in vascular complications. In this study, we investigated the role of adipokines, oleic acid (OA), palmitic acid (PA), and the combinations on activation of NF-κB target genes in human vascular smooth muscle cells (SMC) to assess the hypothesis of synergistic interactions between these molecules. Adipocyte-conditioned medium (CM), generated from human adipocytes, in combination with low concentrations of OA, but not PA, induces SMC proliferation and activation of the transcription factor NF-κB in a synergistic way. Combined treatment of CM and OA further regulates a set of downstream NF-κB target genes including angiopoietin-1, activin A, and MMP-1, all critically involved in SMC dysfunction. This suggests that the lipotoxic potential of fatty acids is substantially enhanced by the presence of adipocyte-derived factors.

[I can hear you, but I don't understand you. Why is it so important to perceive high frequencies?]

The word personality is derived from the Latin word "persona" (mask, person); "per sona" means "by the sound or through the sound". In order to look through speech, to hear "behind the mask of a person", we have to be able to hear properly. Especially the frequencies between 2 kHz and 5 kHz and the overtones (the higher we can perceive them, the better) play a central role for decoding vowels, consonants and effects of emotions in voice and speech; beyond that they provide the perfect enjoyment of music and sound. Obviously they are also a vital physical necessity. High frequencies stimulate, they provoke attentiveness and concentration. The activity level of the reticular formation is affected by the influent of the sensory organs with a crucial role by the hearing sense. Hearing in high frequencies leads to higher metabolism, to better motility, to an activation of the gamma nervous system and to a better transfer of information.

P1-12-16: HER-2 Testing and Treatment – Is Age a Factor?

Aims: Elderly breast cancer patients have a poorer prognosis due to late diagnosis and sub-optimal treatment. In the UK, HER-2 testing was introduced in 2005 and we sought to determine whether HER-2 testing was performed on patients of all ages and whether HER-2 positive patients of all ages subsequently received Herceptin, from implementation in 2005 until 2008.

Methods: Review of all newly diagnosed breast cancers in women over 50 in our Unit between January 2005 and December 2008 was performed. Cases were identified from the hospital pathology electronic database. Patients were considered HER-2 positive if tissue sections scored 3+ on immunohistochemical analysis (intense membranous staining) or if gene amplification was detected using fluorescence in-situ hybridisation (FISH). Patients were eligible for treatment with Herceptin if the tumour exceeded 1cm in size or if they had lymph-node positive disease, per UK guidelines. Herceptin treatment was determined for all patients.

Results: In total 703 patients with a median age of 68 years (range 56 to 98) were identified and 628 (89.3%) underwent definitive surgery (mastectomies: 246; wide local excisions: 382) and axillary surgery. In total 371 patients (52.8%) underwent HER-2 testing by immunohistochemistry or FISH. HER-2 tests performed by year: 2005 (51/131; 38.9%); 2006 (59/187; 31.6%); 2007 (71/189; 37.6%) and 2008 (190/196; 96.9%). Fifty six patients (15.1%) were HER-2 positive by immunohistochemistry or FISH. Median age of HER2 positive patients was 66 years (range 57 to 98); median age of HER2 negative patients was 68 years (range 56 to 96). Forty four HER-2 positive patients (78.6%) were eligible for treatment with Herceptin; of these 28 patients (63.6%) were treated with Herceptin. HER2 testing, treatment with Herceptin and overall 5-year mortality rate for patients between 50 to 69 years and patients aged 70 years or older is summarised in Table1.

Insights from studies with oral cleft genes suggest associations between WNT-pathway genes and risk of oral cancer

Oral squamous cell carcinoma (OSCC) accounts for more than 90% of the malignant neoplasms that arise in the mucosa of the upper aerodigestive tract. Recent studies of cleft lip/palate have shown the association of genes involved in cancer. WNT pathway genes have been associated with several types of cancer and recently with cleft lip/palate. To investigate if genes associated with cleft lip/palate were also associated with oral cancer, we genotyped 188 individuals with OSCC and 225 control individuals for markers in AXIN2, AXIN1, GSK3β, WNT3A, WNT5A, WNT8A, WNT11, WNT3, and WNT9B. Statistical analysis was performed with PLINK 1.06 software to test for differences in allele frequencies of each polymorphism between cases and controls. We found association of SNPs in GSK3B (p = 0.0008) and WNT11 (p = 0.03) with OSCC. We also found overtransmission of GSK3B haplotypes in OSCC cases. Expression analyses showed up-regulation of WNT3A, GSK3B, and AXIN1 and down-regulation of WNT11 in OSCC in comparison with control tissues (P < 0.001). Additional studies should focus on the identification of potentially functional variants in these genes as contributors to human clefting and oral cancer.

Abstract P4-05-05: Stromal Response to 14-Day Preoperative Therapy in Postmenopausal Oestrogen Receptor Positive Breast Cancer

Background: Stromal-epithelial interaction is a key factor in tumour progression. Cancer-associated fibroblasts (CAFs) and macrophage infiltration have been associated with early relapse in breast cancer. Bisphosphonates are effective inhibitors of osteoclast activation in metastatic breast cancer but also have a general inhibitory effect on breast cancer progression. In order to monitor a potential tumour stromal response in breast cancer during treatment with an aromatase inhibitor and a bisphosphonate we analysed pre-and post-treatment samples from a neoadjuvant window study and focused on the presence of macrophages and CAFs.

Materials and methods: Tissue microarrays (TMAs) from surgical samples and pre-operative core biopsies were immunohistochemically stained for aSMA (CAF marker), CD68 (macrophages) and epithelial proliferation (Ki67). In order to validate if the presence of macrophages and aSMA could be monitored by the TMA approach, we initially analysed a screening cohort of 144 breast cancer samples. We then studied pre-and post-treatment samples from 110 postmenopausal ER-positive invasive breast cancer patients randomised to receive 14 days of preoperative treatment (placebo, Letrozole, or Letrozole plus Zoledronate). Results: In the screening cohort, we observed significant links between aSMA positive fibroblasts and disease recurrence as well as between CD68 positive macrophages and tumour size, grade, lymph node positivity and recurrence. This validated the use of TMAs for stromal analyses and furthersupported a link with key tumour biological events. In both treatment arms, there was a significant drop in absolute Ki67 value compared to placebo (-9.3% Letrozole and -13.1% combination reduction versus 1% increase, P&lt;0.001). Post-treatment CD68 (median 35, range 3 to 117) was significantly linked to a Ki67 drop (p=0.045). Interestingly, this effect was mainly observed in the combination treatment group (p=0.002). aSMA expression was unaffected during treatment in 52%, increased in 35% and decreased in 13% of cases. Patients with aSMA reduction post treatment had a larger Ki67 fall compared to patients with increase or no change in aSMA (p=0.007).

Conclusion: Short term treatment response in the epithelial component of cancers was paralleled by specific responses in the tumour stromal component. These novel findings suggest that bisphosphonates and aromatase inhibitors have major effects on tumour stroma in vivo which might augment their inhibitory effect on tumour progression.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P4-05-05.

Abstract P3-10-31: Epithelial Proliferation (Ki67) Is Not an Independent Variable for Breast Cancer Relapse in Symptomatic or Screen Detected Breast Cancers (SDBC)

Background: UK screen detected breast cancers (SDBC) (aged 50-65 years) have an overall 97.2% 5 year relative survival compared to 77.6% for symptomatic cancers. Epithelial proliferation has been used to determine therapy in the St. Gallen guidelines (Ki67 ≥30% indicates the need for chemotherapy).

Methods: To determine the value of Ki67 in post-menopausal breast cancer in women aged 50-65 years, we have studied Ki67 in 1270 women aged 50-65 years (mean 57 years) with either symptomatic cancers (n=412) or SDBC (n=858) with a 10 year follow up.

Results: Ki67 predicted relapse and death in both symptomatic and SDBC. Mode of detection, size, grade, node status and oestrogen receptor (ER) were independently predictive of breast cancer mortality and Ki67 was not an independent variable. In small size ≤15mm ER positive SDBC (n=248) or symptomatic cancers (n=146), Ki67 was not prognostic (p=0.13 and 0.59 respectively). Twelve per cent of symptomatic and 2% of SDBC had died within 5 years. Mean Ki67 in SDBC was 21.4 (SD 10.3) and 34.2 (SD 16.2) in symptomatic cancers (p=≤0.001). ER positive cancers had lower Ki67 levels (p=0.002). For each 10 unit increase in Ki67, increases in distant relapse occurred (RR 1.43:95%CI;1.32-1.55).

Ten Year Survival According to Ki67 and Mode of Presentation

Discussion: Epithelial proliferation is prognostic in breast cancer but its value is predominantly in large size (≥15mm) symptomatic tumours and Ki67 alone cannot be used to determine therapy.

Randomised Placebo Controlled Trial Studying Short Term Biological Effects of the Combination of Letrozole and Zoledronic Acid on Invasive Breast Cancer

To determine whether the addition of Zoledronic Acid to endocrine therapy increases apoptosis or decreases proliferation in early invasive breast cancer, a placebo controlled randomised trial comparing 14 days treatment with Letrozole or Letrozole and Zoledronic Acid pre-operatively was performed.PatientsIn total 109 postmenopausal women with early invasive hormone receptor positive breast cancer were randomised (1:1:1) to either placebo, Letrozole 2.5mg/day or Letrozole with Zoledronic Acid 4mg single dose intravenously 2-4 days before definitive surgical excision. Epithelial proliferation and apoptosis were measured on paired baseline and surgical biopsy specimens (after 14 days of treatment) using Ki67 and Activated Caspase 3 immunohistochemistry. Alterations in angiogenic markers (VCAM/VEGF and CD31) were also studied. The primary endpoint was fall in Ki67 between diagnosis and surgical excision.ResultsOverall 109 women were enrolled but paired biopsies were only available for 101 patients. PlaceboLetrozoleLet + Zoln323435Absolute Ki67 change (median,range)-0.8 (-12,12)8.6 (-14,37)12.9 (-12,29)    Caspase 3 change (median,range)0.1 (-3.8, 9.3)0.4 (-2.7, -4.1)0.2 (-10.9, -14.4)    Absolute change (Cell turnover index)-0.3 (-142, -59)18.9 (-201, 192)17.7 (-14, 379) Statistically significant reductions in Ki67 and Cell Turnover Index were seen with Letrozole and Let & Zol (p ≤ 0.001) but there was no significant different between Letrozole and Letrozole plus Zoledronic Acid groups (p = 0.26). Apoptosis did not change between the three groups.ConclusionLetrozole reduces proliferation by 70% when used for 14 days prior to surgery. Zoledronic Acid administration prior to surgery is safe but when administered as a single dose at a median of 3 days before surgery did not significantly increase apoptosis or decrease proliferation compared to Letrozole alone.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2009.

Chemerin is a novel adipocyte-derived factor inducing insulin resistance in primary human skeletal muscle cells

OBJECTIVE

Chemerin is an adipokine that affects adipogenesis and glucose homeostasis in adipocytes and increases with BMI in humans. This study was aimed at investigating the regulation of chemerin release and its effects on glucose metabolism in skeletal muscle cells.

RESEARCH DESIGN AND METHODS

Human skeletal muscle cells were treated with chemerin to study insulin signaling, glucose uptake, and activation of stress kinases. The release of chemerin was analyzed from in vitro differentiated human adipocytes and adipose tissue explants from 27 lean and 26 obese patients.

RESULTS

Human adipocytes express chemerin and chemokine-like receptor 1 (CMKLR1) differentiation dependently and secrete chemerin (15 ng/ml from 10(6) cells). This process is slightly but significantly increased by tumor necrosis factor-alpha and markedly inhibited by >80% by peroxisome proliferator-activated receptor-gamma activation. Adipose tissue explants from obese patients are characterized by significantly higher chemerin secretion compared with lean control subjects (21 and 8 ng from 10(7) cells, respectively). Chemerin release is correlated with BMI, waist-to-hip ratio, and adipocyte volume. Furthermore, higher chemerin release is associated with insulin resistance at the level of lipogenesis and insulin-induced antilipolysis in adipocytes. Chemerin induces insulin resistance in human skeletal muscle cells at the level of insulin receptor substrate 1, Akt and glycogen synthase kinase 3 phosphorylation, and glucose uptake. Furthermore, chemerin activates p38 mitogen-activated protein kinase, nuclear factor-kappaB, and extracellular signal-regulated kinase (ERK)-1/2. Inhibition of ERK prevents chemerin-induced insulin resistance, pointing to participation of this pathway in chemerin action.

CONCLUSIONS

Adipocyte-derived secretion of chemerin may be involved in the negative cross talk between adipose tissue and skeletal muscle contributing to the negative relationship between obesity and insulin sensitivity.

Addition of pathology and biomarker information significantly improves the performance of the Manchester scoring system for BRCA1 and BRCA2 testing

BACKGROUND

Selection for genetic testing of BRCA1/BRCA2 is an important area of healthcare. Although testing costs for mutational analysis are falling, costs in North America remain in excess of US$3000 (UK price can be 690 pounds). Guidelines in most countries use a 10-20% threshold of detecting a mutation in BRCA1/2 combined within a family before mutational analysis is considered. A number of computer-based models have been developed. However, use of these models can be time consuming and difficult. The Manchester scoring system was developed in 2003 to simplify the selection process without losing accuracy.

METHODS

In order to increase accuracy of prediction, breast pathology of the index case was incorporated into the Manchester scoring system based on 2156 samples from unrelated non-Jewish patients fully tested for BRCA1/2, and the scores were adapted accordingly. Results/

DISCUSSION

Data from breast pathology allowed adjustment of BRCA1 and combined BRCA1/2 scores alone. There was a lack of pathological homogeneity for BRCA2, therefore specific pathological correlates could not be identified. Upward adjustments in BRCA1 mutation prediction scores were made for grade 3 ductal cancers, oestrogen receptor (ER) and triple-negative tumours. Downward adjustments in the score were made for grade 1 tumours, lobular cancer, ductal carcinoma in situ and ER/HER2 positivity. Application of the updated scoring system led to four and nine more mutations in BRCA1 being identified at the 10% and 20% threshold, respectively. Furthermore, 65 and 58 fewer cases met the 10% and 20% threshold, respectively, for testing. Moreover, the adjusted score significantly improved the trade-off between sensitivity and specificity for BRCA1/2 prediction.

Short-term biological effects of zoledronic acid combined with letrozole in postmenopausal women with estrogen receptor-positive invasive breast cancer

e11625

Background: Aromatase inhibitors (AIs) reduce tumor cell proliferation and improve breast cancer survival. Recent evidence from in vivo models and the ABCSG-12 Trial suggests that bisphosphonates such as zoledronic acid add to the inhibitory effect of AIs but the mechanism is unclear. We assessed the effect of letrozole alone and in combination with zoledronic acid in a 14 day pre-surgical study in women with primary breast cancer. Methods: Postmenopausal women (n=109) aged 50–75 years with untreated estrogen receptor positive invasive breast cancer (no prior hormonal therapy) gave written informed consent to the study and were randomized to letrozole (2.5mg) or placebo tablets (2:1). Letrozole treated patients were randomized further to zoledronic acid 4mg intravenously or no treatment 2–4 days prior to surgery. Epithelial proliferation and apoptosis was measured pre and post treatment by immunohistochemistry for Ki67 and activated caspase 3 respectively counting at least 1,000 cells. Smooth Muscle Actin immunohistochemistry was also assessed pre and post treatment to determine fibroblast activation. Results: The study is powered to detect a 10% difference in epithelial proliferation with the combination arm (80% chance) compared to the letrozole alone arm. Conclusions: This preoperative biological study should provide important insight into the cellular mechanism or action of zoledronic acid in addition to AIs on primary breast cancer.

[Table: see text]

Cannabinoid type 1 receptors in human skeletal muscle cells participate in the negative crosstalk between fat and muscle

AIMS/HYPOTHESIS

Cannabinoid type 1 receptor (CB1R) antagonists such as rimonabant (Rim) represent a novel approach to treat obesity and related metabolic disorders. Recent data suggest that endocannabinoids are also produced by human adipocytes. Here we studied the potential involvement of endocannabinoids in the negative crosstalk between fat and muscle.

METHODS

The protein level of CB1R in human skeletal muscle cells (SkM) during differentiation was analysed using western blotting. SkM were treated with adipocyte-conditioned medium (CM) or anandamide (AEA) in combination with the CB1R antagonists Rim or AM251, and insulin-stimulated Akt phosphorylation and glucose uptake were determined. Furthermore, signalling pathways of CB1R were investigated.

RESULTS

We revealed an increase of CB1R protein in SkM during differentiation. Twenty-four hour incubation of SkM with CM or AEA impaired insulin-stimulated Akt(Ser473) phosphorylation by 60% and up to 40%, respectively. Pretreatment of cells with Rim or AM251 reduced the effect of CM by about one-half, while the effect of AEA could be prevented completely. The reduction of insulin-stimulated glucose uptake by CM was completely prevented by Rim. Short-time incubation with AEA activated extracellular regulated kinase 1/2 and p38 mitogen-activated protein kinase, and impaired insulin-stimulated Akt(Ser473) phosphorylation, but had no effect on Akt(Thr308) and glycogen synthase kinase 3alpha/beta phosphorylation. In addition, enhanced IRS-1 (Ser307) phosphorylation was observed.

CONCLUSIONS/INTERPRETATION

Our results show that the CB1R system may play a role in the development of insulin resistance in human SkM. The results obtained with CM support the notion that adipocytes may secrete factors which are able to activate the CB1R. Furthermore, we identified two stress kinases in the signalling pathway of AEA and enhanced IRS-1(Ser307) phosphorylation, potentially underlying the development of insulin resistance.

Further delineation of the phenotype resulting fromBRAForMEK1germline mutations helps differentiate cardio-facio-cutaneous syndrome from Costello syndrome

Because Cardio-facio-cutaneous (CFC) syndrome has significant phenotypic overlap with Costello syndrome, it may be difficult to establish the diagnosis on a clinical basis. The recent discoveries of germline HRAS mutations in patients with Costello syndrome and mutations in BRAF, MEK1, and MEK2 in CFC syndrome uncovered the biologic mechanism for the shared phenotypic findings based on the close interaction of the affected gene products within the MAP kinase pathway. We evaluated a series of patients who were either clinically diagnosed with Costello syndrome, or in whom the diagnoses of both Costello and CFC syndromes were considered. After excluding mutations in HRAS, we identified eight changes in BRAF and five in MEK1. Five mutations are novel, and all changes occurred de novo among those triads tested. A review of the clinical abnormalities showed important differences between patients with either a BRAF or MEK1 mutation, and those previously reported with an HRAS mutation. Statistical significance was achieved, despite the relatively small number of patients with BRAF and MEK1 mutations reported here, for polyhydramnios, growth hormone deficiency and the presence of more than one papilloma, which were less common in CFC compared to HRAS mutation positive patients. Although both CFC and Costello syndrome are characterized by cardiac abnormalities in about three-fourths of patients, the pattern of congenital heart defects (CHD), hypertrophic cardiomyopathy (HCM), and tachycardia differs somewhat. CHD, especially pulmonic stenosis associated with a secundum-type atrial septal defect, are more common in CFC than Costello syndrome (P = 0.02). Atrial tachycardia is less frequent in CFC patients with BRAF or MEK1 mutations, compared to Costello syndrome patients with HRAS mutation (P = 0.04). Chaotic atrial rhythm or multifocal atrial tachycardia was observed only in Costello syndrome. Malignant tumors have been viewed as characteristic for Costello syndrome due to HRAS mutations, however, we report here on a MEK1 mutation in a patient with a malignant tumor, a hepatoblastoma. Although this indicates that the presence of a tumor is not specific for Costello syndrome with HRAS mutation, it is noteworthy that the tumor histology differs from those commonly seen in Costello syndrome. Based on these clinical differences we suggest that patients with BRAF and MEK mutations should be diagnosed with CFC syndrome, and the diagnosis of Costello syndrome be reserved for patients with HRAS mutations.

Activated c-SRC in ductal carcinoma in situ correlates with high tumour grade, high proliferation and HER2 positivity

Overexpression and/or activity of c-Src non-receptor tyrosine kinase is associated with progression of several human epithelial cancers including breast cancer. c-Src activity in ‘pure’ ductal carcinoma in situ (DCIS) was measured to assess whether this predicts recurrence and/or correlates with HER2 expression and other clinical parameters. Activated c-Src levels were evaluated in DCIS biopsies from 129 women, with median follow-up at 60 months. High levels of activated c-Src correlated with HER2 positivity, high tumour grade, comedo necrosis and elevated epithelial proliferation. In univariate analysis, high activated c-Src level associated with lower recurrence-free survival at 5 years (P=0.011). Thus, high c-Src activity may identify a subset of DCIS with high risk of recurrence or progression to invasive cancer where therapeutics targeting c-Src may benefit this patient subset.

Primary synovial chondromatosis of the elbow

Very few cases of primary synovial chondromatosis of the elbow have been reported in the literature. This is a study concerning the late outcome of primary synovial chondromatosis in the elbows of 12 patients, 10 men and 2 women, with a mean follow-up of 16 years 10 months. The average age at the time of the initial complaint was 29 years. The histories of 10 patients revealed elbow strain as a consequence of work-related activities. Surgery included removal of loose bodies and partial synovectomy in all patients. A moderate to severe osteoarthritis was found preoperatively in 5 of 12 patients and during follow-up in 7 of 10 patients. The degree of osteoarthritis deteriorated after surgery in 5 of these cases, depending on patient age, length of presurgical history, length of follow-up, and strenuous activities. However, the functional deficiencies were usually moderate and had little significance with respect to the activities of daily living. No recurrence of primary synovial chondromatosis was found.

A qualitative analysis of family member needs and concerns in the population of patients with burns

The importance of family support to ameliorate the recovery of a patient with burns has been documented in the literature. However, there is a dearth of research that identifies family members' needs and concerns during the hospitalization of patients with burns. Study aims were as follows: (1) identify support needs and concerns of family members of adult and pediatric patients currently in a burn center and (2) explore the relationship between family needs and the patient's severity of injury. An observational design was used that incorporated semistructured interviews with family members 1 to 3 days after the burn. A convenience sample of family members of burn center patients (n = 97) was recruited over 9 months. Content analysis was used to establish themes from interview data. Interrater reliability on coding of thematic units from 15% of the interviews was 86%; discrepancies were corrected to 100%. The average family member was 42.3 years old, female, white, and at least a high school graduate. Family members' concerns included general patient concerns, physical concerns about the patient, satisfaction of personal needs, and psychologic concerns about the patient. Major sources of support were family and friends, burn center staff, and spirituality. Family members of pediatric patients identified pain and skin graft surgery as priority worries. Satisfaction of personal needs, financial support, and information needs were greater among family members of intensive care unit patients in comparison with step-down patients. These findings underscore the importance of communication and reassurance between the burn team and the family members. Alterations to the support provided to families can be made on the basis of study subjects' responses.

Effect of methyltransferase inhibitors on the regulation of baculovirus protein synthesis

In the presence of the methyltransferase inhibitor 3-deazaadenosine (3DA-Ado) the production of infectious Autographa californica nuclear polyhedrosis virus (AcMNPV) in tissue culture was only slightly affected, while the synthesis of very late proteins (polyhedrin and p10) was abolished. The synthesis of the influenza virus proteins NS1 and HA, expressed under the polyhedrin promoter, was also abolished by 3DA-Ado. Furthermore, 3DA-Ado interfered with the shut-off of early and late AcMNPV proteins. Most of these results were also obtained with 5-azadeoxycytidine (5A-dCyt). In cells in which NS1 was produced abundantly, at least one specific AcMNPV protein was not synthesized. However, if the production of NS1 was inhibited by 3DA-Ado, or if HA was synthesized instead, this AcMNPV protein showed up normally.

Endotoxin "priming" potentiates lung vascular abnormalities in response to Escherichia coli hemolysin: an example of synergism between endo- and exotoxin

The pore-forming hemolysin of Escherichia coli (HlyA), an important virulence factor in extraintestinal E. coli infections, causes thromboxane generation and related vasoconstriction in perfused rabbit lungs (Seeger, W., H. Walter, N. Suttorp, M. Muhly, and S. Bhakdi. 1989. J. Clin. Invest. 84:220). We investigated the influence of pulmonary vascular "priming" with endotoxin on the responsiveness of the lung to a low-dose HlyA challenge. Rabbit lungs were perfused with Krebs Henseleit buffer containing 0.1-100 ng/ml Salmonella abortus equii lipopolysaccharide (LPS) for 60-180 min. This treatment caused protracted release of tumor necrosis factor into the recirculating medium, but did not induce significant alterations of pulmonary hemodynamics and fluid balance. At a dose of 1 ng/ml, HlyA elicited only moderate thromboxane release (< 200 pg/ml) and pulmonary artery pressure increase (< or = 6 mmHg) in control lungs. Acceleration and potentiation of both the metabolic and vasoconstrictor response occurred in lungs primed with LPS. This priming effect displayed dose (threshold integral of 0.1-1 ng/ml LPS) and time dependencies (threshold integral of 60-90 min LPS incubation). Maximum thromboxane release and pulmonary artery pressure increase surpassed the responses to HlyA in nonprimed lungs by more than 15-fold. Cyclooxygenase inhibition and thromboxane-receptor antagonism blocked these effects. These data demonstrate that LPS priming synergizes with HlyA challenge to provoke vascular abnormalities that are possibly relevant to the pathogenesis of organ failure in severe local and systemic infections.

Rescue of vector-expressed fowl plague virus hemagglutinin in biologically active form by acidotropic agents and coexpressed M2 protein

The hemagglutinin of the Rostock strain of fowl plague virus was expressed in CV-1 cells by a simian virus 40 vector, and its stability in the exocytotic transport process was examined by a fusion assay. A 50-fold increase in the fusion activity of the hemagglutinin was observed when expression occurred in the presence of ammonium chloride, Tris-HCl, or high doses of amantadine. When chloroquine, another acidotropic agent, was used, the hemagglutinin exposed at the cell surface had to be activated by trypsin, because intracellular cleavage was inhibited by this compound. Hemagglutinin mutants resistant to intracellular cleavage did not require acidotropic agents for full expression of fusion activity, when treated with trypsin after arrival at the cell surface. These results indicate that fowl plague virus hemagglutinin expressed by a simian virus 40 vector is denatured in the acidic milieu of the exocytotic pathway and that cleavage is a major factor responsible for the pH instability. Coexpression with the M2 protein also markedly enhanced the fusion activity of the hemagglutinin, and this effect was inhibited by low doses of amantadine. These results support the concept that M2, known to have ion channel function, protects the hemagglutinin from denaturation by raising the pH in the exocytotic transport system. The data also stress the importance of acidotropic agents or coexpressed M2 for the structural and functional integrity of vector-expressed hemagglutinin.