Variation in IL6ST cytokine family function and the potential of IL6 trans-signalling in ERα positive breast cancer cells

High expression of the transmembrane receptor IL6ST (gp130) has been identified as a predictive biomarker of endocrine treatment response in ERα-positive breast cancers. To investigate its function further in this disease, this study evaluated the expression, function and signalling of IL6ST in ERα-positive breast cancer cell lines and investigated crosstalk between ERα and IL6ST. IL6ST was differentially expressed in ERα-positive breast cancer cell lines (low in MCF-7, high in ZR751 and T47D), while multiple soluble isoforms of IL6ST were identified. IL6ST is the common signal transducing receptor component for the IL6ST family of cytokines and the effects of seven IL6ST cytokines on these cell lines were studied. These cytokines caused differential growth and migration effects in these cell lines e.g. MCF-7 cells were growth-stimulated, while ZR751 cells were inhibited by IL6 and OSM.. Activation of the STAT and ERK pathways is associated with these responses. Evidence to support trans-signalling involved in cell growth and migration was obtained in both MCF-7 and ZR751 models. Interaction between cytokines and estrogen on ERα-positive cell lines growth were analysed. High expression of IL6ST (in ZR751) may lead to growth inhibition by interacting cytokines while lower expression (in MCF-7) appears associated with proliferation. High IL6ST expression is consistent with a more beneficial clinical outcome if cytokine action contributes to anti-estrogen action.

Control of cell state transitions

Understanding cell state transitions and purposefully controlling them is a longstanding challenge in biology. Here we present cell state transition assessment and regulation (cSTAR), an approach for mapping cell states, modelling transitions between them and predicting targeted interventions to convert cell fate decisions. cSTAR uses omics data as input, classifies cell states, and develops a workflow that transforms the input data into mechanistic models that identify a core signalling network, which controls cell fate transitions by influencing whole-cell networks. By integrating signalling and phenotypic data, cSTAR models how cells manoeuvre in Waddington's landscape1 and make decisions about which cell fate to adopt. Notably, cSTAR devises interventions to control the movement of cells in Waddington's landscape. Testing cSTAR in a cellular model of differentiation and proliferation shows a high correlation between quantitative predictions and experimental data. Applying cSTAR to different types of perturbation and omics datasets, including single-cell data, demonstrates its flexibility and scalability and provides new biological insights. The ability of cSTAR to identify targeted perturbations that interconvert cell fates will enable designer approaches for manipulating cellular development pathways and mechanistically underpinned therapeutic interventions.

Predicting Response to Radiotherapy in Cancer-Induced Bone Pain: Cytokines as a Potential Biomarker?

AIMS

Radiotherapy (XRT) for cancer-induced bone pain (CIBP) has varying levels of efficacy. A biomarker that predicts likely efficacy could stratify XRT to those most likely to benefit. No biomarker is used in clinical practice, but potential candidate cytokines have been identified. The aim of the present study was to examine the relationship between candidate cytokines and analgesic response after XRT.

MATERIALS AND METHODS

An exploratory analysis was undertaken on biobank data from patients who had received single fraction (8 Gy) XRT for CIBP. The biobank data were prospectively collected from multiple centres in the UK as part of a larger clinical trial, which had institutional review board approval and all patients provided written informed consent for the use of their data in future research. Phenotypic data, pain assessments as well as plasma samples were collected at baseline (within the 24 h before the XRT) and at follow-up (4 weeks after XRT). Baseline and follow-up samples were analysed and levels of 16 pre-identified cytokines were compared in patients classified as XRT 'responders' or 'non-responders'.

RESULTS

Data from 60 patients were analysed. Insulin-like growth factor binding protein 9 (NOV/CCN3/IGFBP-9) and interleukin-1ß (IL-1ß) were identified as potential predictors of response to XRT. A significant relationship was shown between the response to XRT and the ratio of the median level of NOV/CCN3/IGFBP-9 at baseline:follow-up (P = 0.024). Furthermore, for the patients up to 64 years of age, the median level of NOV/CCN3/IGFBP-9 was significantly different between responders and non-responders (P = 0.047). For IL-1ß, the median level was significantly different between responders and non-responders in patients with breast cancer (P = 0.006).

CONCLUSION

Although the present findings do not identify robust biomarkers, this is the first such study to examine the role of cytokines in predicting response to XRT in patients with CIBP, and studies that build on these findings are encouraged.

Combined targeting of MEK and the glucocorticoid receptor for the treatment of RAS-mutant multiple myeloma

BACKGROUND

Multiple myeloma (MM) remains incurable despite recent therapeutic advances. RAS mutations are frequently associated with relapsed/refractory disease. Efforts to target the mitogen-activated protein kinase (MAPK) pathway with the MEK inhibitor, trametinib (Tra) have been limited by toxicities and the development of resistance. Dexamethasone (Dex) is a corticosteroid commonly used in clinical practice, to enhance efficacy of anti-myeloma therapy. Therefore, we hypothesised that the combination of Tra and Dex would yield synergistic activity in RAS-mutant MM.

METHODS

The response of human MM cell lines to drug treatment was analysed using cell proliferation assays, Western blotting, Annexin V and propidium iodide staining by flow cytometry and reverse phase protein arrays. The efficacy of trametinib and dexamethasone treatment in the MM.1S xenograft model was assessed by measuring tumor volume over time.

RESULTS

The Tra/Dex combination demonstrated synergistic cytotoxicity in KRAS^G12A mutant lines MM.1S and RPMI-8226. The induction of apoptosis was associated with decreased MCL-1 expression and increased BIM expression. Reverse phase proteomic arrays revealed suppression of FAK, PYK2, FLT3, NDRG1 and 4EBP1 phosphorylation with the Tra/Dex combination. Notably, NDRG1 expression was associated with the synergistic response to Tra/Dex. MM cells were sensitive to PDK1 inhibition and IGF1-induced signalling partially protected from Tra/Dex treatment, highlighting the importance of this pathway. In the MM.1S tumor xenograft model, only the combination of Tra/Dex resulted in a significant inhibition of tumor growth.

CONCLUSIONS

Overall Tra/Dex demonstrates antiproliferative activity in RAS-mutant MM cell lines associated with suppression of pro-survival PDK1 signalling and engagement of apoptotic pathways. Our data support further investigation of this combination in RAS-mutant MM.

Abstract 2933: Application of a mouse model humanized for the major pathways of drug disposition in anticancer drug development and use

A vast number of targeted anticancer drugs are being developed in the pharmaceutical industry whose efficacy will only become fully realized through their combination with other established or novel anti-tumor agents. This is particularly the case because combination chemotherapy is a major approach being taken to overcome the rapid onset of drug resistance which current dosing regimens can cause. This has raised the conundrum of which of the large number of possible drug combinations, which may involve combinations of more than two drugs, have the greatest chance of success. It is not possible to test all the possible combinations by clinical trial alone so more informative preclinical models are badly needed. Nearly all targeted anti-tumor agents are substrates for the cytochrome P450-dependent monooxygenase system. The testing of novel drug regimens in mice is severely compromised by the major species differences in this enzyme system both in catalytic function, in the pattern of metabolite formation and the regulation by transcription factors such as CAR and PXR. In order to circumvent this problem we have created a mouse model where thirty four murine P450’s have been deleted from the mouse genome and substituted for the major enzymes involved in drug disposition in man ie CYP1A1, CYP1A2, CYP2C9, CYP2D6, CYP3A4 and CYP3A7. The mice have also been humanized for the transcription factors CAR and PXR. CYP3A4 and CYP2D6 are expressed off the human promoters. We report the validation the utility of this model by studying the in vivo metabolism and disposition of model drugs and the metabolism and disposition of the EGFR inhibitor, osimertinib and the BRAF inhibitor, dabrafenib. We show that the use of this model allows accurate prediction of clinically observed drug exposures, in the generation of human metabolites and drug/drug interactions. This model has therefore great potential for the development of combination therapies involving complex drug regimens and in the design of clinical trials targeted at overcoming drug resistance.

Citation Format: Colin J. Henderson, Nico Scheer, Yury Kapelyukh, Aileen McLaren, Kenneth MacLeod, Anja Rode, De Lin, C Roland Wolf. Application of a mouse model humanized for the major pathways of drug disposition in anticancer drug development and use [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2933.

Mechanical and energetic properties of papillary muscle from ACTC E99K transgenic mouse models of hypertrophic cardiomyopathy

We compared the contractile performance of papillary muscle from a mouse model of hypertrophic cardiomyopathy [α-cardiac actin (ACTC) E99K mutation] with nontransgenic (non-TG) littermates. In isometric twitches, ACTC E99K papillary muscle produced three to four times greater force than non-TG muscle under the same conditions independent of stimulation frequency and temperature, whereas maximum isometric force in myofibrils from these muscles was not significantly different. ACTC E99K muscle relaxed slower than non-TG muscle in both papillary muscle (1.4×) and myofibrils (1.7×), whereas the rate of force development after stimulation was the same as non-TG muscle for both electrical stimulation in intact muscle and after a Ca²⁺ jump in myofibrils. The EC₅₀ for Ca²⁺ activation of force in myofibrils was 0.39 ± 0.33 μmol/l in ACTC E99K myofibrils and 0.80 ± 0.11 μmol/l in non-TG myofibrils. There were no significant differences in the amplitude and time course of the Ca²⁺ transient in myocytes from ACTC E99K and non-TG mice. We conclude that hypercontractility is caused by higher myofibrillar Ca²⁺ sensitivity in ACTC E99K muscles. Measurement of the energy (work + heat) released in actively cycling heart muscle showed that for both genotypes, the amount of energy turnover increased with work done but with decreasing efficiency as energy turnover increased. Thus, ACTC E99K mouse heart muscle produced on average 3.3-fold more work than non-TG muscle, and the cost in terms of energy turnover was disproportionately higher than in non-TG muscles. Efficiency for ACTC E99K muscle was in the range of 11-16% and for non-TG muscle was 15-18%.

“When can I return to driving?”

Clinicians are often asked by patients, “When can I drive again?” after lower limb injury or surgery. This question is difficult to answer in the absence of any guidelines. This review aims to collate the currently available evidence and discuss the factors that influence the decision to allow a patient to return to driving. Medline, Web of Science, Scopus, and EMBASE were searched using the following terms: ‘brake reaction time’, ‘brake response time’, ‘braking force’, ‘brake pedal force’, ‘resume driving’, ‘rate of application of force’, ‘driving after injury’, ‘joint replacement and driving’, and ‘fracture and driving’. Of the relevant literature identified, most studies used the brake reaction time and total brake time as the outcome measures. Varying recovery periods were proposed based on the type and severity of injury or surgery. Surveys of the Driver and Vehicle Licensing Agency, the Police, insurance companies in the United Kingdom and Orthopaedic Surgeons offered a variety of opinions.

There is currently insufficient evidence for any authoritative body to determine fitness to drive. The lack of guidance could result in patients being withheld from driving for longer than is necessary, or returning to driving while still unsafe.

Cite this article: Bone Joint J 2013;95-B:290–4.

The components of the female athlete triad do not identify all physically active females at risk

The purpose of the present study was to assess the effectiveness of the triad components (amenorrhoea, disordered eating, and osteoporosis) in identifying physically active women at risk of long-term health problems. Eighty-two females (mean age 31.1 years, s = 6.7; body mass 58.4 kg, s = 6.6; stature 1.65 m, s = 0.06) completed training, menstrual, and dietary questionnaires. Bone mineral density and size-adjusted bone mineral density were assessed at the femoral neck and lumbar spine using dual energy X-ray absorptiometry. Seventy-eight percent of participants were eumenorrhoeic, 20% were oligomenorrhoeic, and 2% were amenorrhoeic. Thirty-six percent and 55% reported disordered eating practices in the present and past respectively. Eighty-one percent, 17%, and 2% were classified as normal, osteopaenic, and osteoporotic at the femoral neck respectively; 92% were normal, 7% osteopaenic, and 1% osteoporotic at the lumbar spine. No significant differences in femoral neck size-adjusted bone mineral density were observed between eumenorrhoeic and oligo/amenorrhoeic participants (F(2,80) = 0.119, P = 0.73); eumenorrhoeic participants had significantly greater lumbar spine size-adjusted bone mineral density (F(2,80) = 9.79, P = 0.003). Disordered eating participants had significantly lower femoral neck size-adjusted bone mineral density than those reporting no disordered eating (F(2,80) = 13.816, P = 0.000). Twenty-two percent of participants fulfilled triad criteria, while 55% were "at risk" of long-term health problems. An accumulation of conditions resulted in lower lumbar spine size-adjusted bone mineral density (F(1,80) = 6.074, P = 0.004). The current triad components do not identify all women "at risk" and more appropriate criteria such as exercise-related menstrual alterations, disordered eating, and osteopaenia are suggested.

Progressive loss of estrogen receptor alpha cofactor recruitment in endocrine resistance

Differential expression of estrogen receptor-alpha (ERalpha) cofactors has been implicated in endocrine resistance in breast cancer. Using a three-stage MCF-7 cell-based model that emulates the clinical manifestation of acquired endocrine resistant breast cancer we now show, using a combination of chromatin immunoprecipitation and RNA interference, that there is a progressive loss of ERalpha cofactor recruitment to the estrogen-dependent pS2 gene and reduced requirement for cofactor expression. Maximal estrogen induced pS2 induction requires ERalpha and cofactor recruitment in MCF-7 cells, but in the progression to endocrine resistance these requirements are altered and expression has become less dependent on cofactors. Additionally, in estrogen-resistant MCF-7 cells there is a global loss of requirement of individual cofactors for proliferative cell growth indicating that other genes have lost the need for transcriptional cofactors. This loss of the requirement for cofactors may represent an important mechanism for gene misregulation in cancer.

Estrogen-regulated gene expression predicts response to endocrine therapy in patients with ovarian cancer

OBJECTIVE

To explore the predictive value of estrogen-regulated gene changes as indicators of sensitivity in ovarian cancer patients treated with the aromatase inhibitor Letrozole.

METHODS

Expression of a range of proteins was assessed by semi-quantitative immunohistochemistry in tissue sections from the tumors of patients treated with Letrozole. Expression was correlated with clinical response to Letrozole. Corresponding mRNA in ovarian cancer cell lines treated with 17beta-estradiol (E2) was measured by quantitative RT-PCR.

RESULTS

In an estrogen receptor (ER)-positive ovarian cancer cell line, quantitative RT-PCR analysis demonstrated that PLAU, VIM, BIGH3, CDH6, FN1, CASP4, KRT4, KRT7, KRT13, TRAM and NGAL were down-regulated and TFF1, TFF3, TRAP1, TFAP4, MYC, CTSD, IL17BR, TOP2A, CCNB1, CCNB2, PDZK1 and UBE2C were up-regulated by E2. The E2 modulation of these genes was reversed by the anti-estrogen tamoxifen and was ERalpha-dependent. For ovarian cancer patients treated with Letrozole, we tested the predictive value of the majority of these genes in paraffin sections from their primary tumors by semi-quantitative immunohistochemistry. Significant differences in expression levels of TFF1, TFF3, BIGH3, TRAP1, VIM, TOP2A, PLAU and UBE2C were observed between tumors from CA125 responsive/stable patients as opposed to tumors from patients whose disease progressed, using serum levels of CA125 as an indicator of response. Aromatase expression in the ovarian cancers also differed between these 2 groups of patients.

CONCLUSION

These results suggest that expression levels of certain proteins in ovarian cancers are estrogen-regulated and could help identify patients who would benefit from endocrine therapy.

Insulin-like growth factor binding proteins IGFBP3, IGFBP4, and IGFBP5 predict endocrine responsiveness in patients with ovarian cancer

PURPOSE

This study sought to explore the predictive value of the insulin-like growth factor (IGF) binding proteins (IGFBP) as markers of response in ovarian cancer patients treated with the aromatase inhibitor letrozole.

EXPERIMENTAL DESIGN

IGFBP mRNA expression in cell lines was measured by quantitative reverse transcription-PCR and IGFBP protein expression measured in sections from primary tumors of patients treated with letrozole by semiquantitative immunohistochemistry.

RESULTS

Quantitative reverse transcription-PCR analysis showed that IGFBP3 and IGFBP5 were down-regulated and IGFBP4 was up-regulated by 17beta-estradiol (E(2)) in an estrogen receptor (ER)-positive ovarian cancer cell line. Expressions of IGFBP1, IGFBP2, and IGFBP6 were unaffected by E(2). The E(2) modulation of these genes was reversed by tamoxifen. Using ERalpha-specific (propyl pyrazole triol) and ERbeta-specific (diarylpropionitrile) agonists, the gene expression modulations produced by E(2) could be replicated by propyl pyrazole triol but not by diarylpropionitrile. For ovarian cancer patients being treated with letrozole, we tested the predictive value of the IGFBPs in paraffin-fixed sections from their primary tumors by semiquantitative immunohistochemistry. Using serum CA125 as an indicator of progression/response, significant differences in expression levels of IGFBPs were observed between tumors from CA125 responding/stable patients compared with tumors from progressing patients. Mean immunoscores for IGFBP3 and IGFBP5 were significantly lower, and mean expression of IGFBP4 was significantly higher in tumors from patients demonstrating CA125 response or stabilization compared with CA125 progression.

CONCLUSION

These results indicate that expression levels of certain IGFBP family members in ovarian cancers are estrogen regulated and can, thus, help identify patients who could benefit from endocrine therapy.

[Metabolic control by means of insulin in patients with type 2 diabetes and acute myocardial infarction (DIGAMI 2): effects on mortality and morbidity--secondary publication]

Patients with diabetes have an unfavourable prognosis after an acute myocardial infarction. The DIGAMI 2 study investigated the effect of various metabolic treatment strategies in type 2 diabetic patients with acute myocardial infarction: acutely introduced, long-term insulin treatment did not improve survival when compared with conventional management at similar levels of glucose control. However, good glucose control seems important since the glucose level was found to be a strong predictor of long-term mortality in this patient category.

Intense metabolic control by means of insulin in patients with diabetes mellitus and acute myocardial infarction (DIGAMI 2): effects on mortality and morbidity

AIMS

Patients with diabetes have an unfavourable prognosis after an acute myocardial infarction. In the first DIGAMI study, an insulin-based glucose management improved survival. In DIGAMI 2, three treatment strategies were compared: group 1, acute insulin-glucose infusion followed by insulin-based long-term glucose control; group 2, insulin-glucose infusion followed by standard glucose control; and group 3, routine metabolic management according to local practice.

METHODS AND RESULTS

DIGAMI 2 recruited 1253 patients (mean age 68 years; 67% males) with type 2 diabetes and suspected acute myocardial infarction randomly assigned to groups 1 (n=474), 2 (n=473), and 3 (n=306). The primary endpoint was all-cause mortality between groups 1 and 2, and a difference was hypothesized as the primary objective. The secondary objective was to compare total mortality between groups 2 and 3, whereas morbidity differences served as tertiary objectives. The median study duration was 2.1 (interquartile range 1.03-3.00) years. At randomization, HbA1c was 7.2, 7.3, and 7.3% in groups 1, 2, and 3, respectively, whereas blood glucose was 12.8, 12.5, and 12.9 mmol/L, respectively. Blood glucose was significantly reduced after 24 h in all groups, more in groups 1 and 2 (9.1 and 9.1 mmol/L) receiving insulin-glucose infusion than in group 3 (10.0 mmol/L). Long-term glucose-lowering treatment differed between groups with multidose insulin (> or =3 doses/day) given to 15 and 13% of patients in groups 2 and 3, respectively compared with 42% in group 1 at hospital discharge. By the end of follow-up, HbA1c did not differ significantly among groups 1-3 ( approximately 6.8%). The corresponding values for fasting blood glucose were 8.0, 8.3, and 8.6 mmol/L. Hence, the target fasting blood glucose for patients in group 1 of 5-7 mmol/L was never reached. The study mortality (groups 1-3 combined) was 18.4%. Mortality between groups 1 (23.4%) and 2 (22.6%; primary endpoint) did not differ significantly (HR 1.03; 95% CI 0.79-1.34; P=0.831), nor did mortality between groups 2 (22.6%) and 3 (19.3%; secondary endpoint) (HR 1.23; CI 0.89-1.69; P=0.203). There were no significant differences in morbidity expressed as non-fatal reinfarctions and strokes among the three groups.

CONCLUSION

DIGAMI 2 did not support the fact that an acutely introduced, long-term insulin treatment improves survival in type 2 diabetic patients following myocardial infarction when compared with a conventional management at similar levels of glucose control or that insulin-based treatment lowers the number of non-fatal myocardial reinfarctions and strokes. However, an epidemiological analysis confirms that the glucose level is a strong, independent predictor of long-term mortality in this patient category, underlining that glucose control seems to be an important part of their management.

Antisense oligonucleotide targeting of Raf-1: importance of raf-1 mRNA expression levels and raf-1-dependent signaling in determining growth response in ovarian cancer

PURPOSE

We sought to identify determinants of growth response to the Raf-1-targeted antisense oligonucleotide (ASO; ISIS 5132) using a large panel of ovarian cancer cell lines.

EXPERIMENTAL DESIGN

First-(ISIS 5132) and second-generation (ISIS 13650) anti-Raf 1 ASOs were compared with control oligonucleotides. Growth was assessed by cell counts; apoptosis was assessed by poly(ADP-ribose) polymerase cleavage; and cell cycle analysis was assessed by flow cytometry. Protein expression was detected by Western blot analysis, and mRNA expression was detected by quantitative reverse transcription-PCR. Raf-1 kinase activity was detected by anti-Raf-1 immunoprecipitation, followed by myelin basic protein phosphorylation.

RESULTS

A panel of 15 ovarian cancer cell lines was used to model a range of growth responses to ASOs targeting Raf-1 mRNA. Growth inhibition varied from 10% to >90% inhibition. Growth inhibition was associated with increased apoptosis and accumulation of cells in the G(2)-M and S phases of the cell cycle. Growth response was not related to level of Raf-1 protein expression, Raf-1 kinase activity, intracellular ASO uptake, or degree of Raf-1 protein inhibition. However, ASO growth response was associated with a high proportion of Raf-1 mRNA [relative to total (i.e., Raf-1 + A-Raf + B-Raf) Raf mRNA] and significantly higher Raf-1 kinase activity induction following growth factor (transforming growth factor alpha) stimulation in the cell lines consistent with dependency of these cell lines on Raf-1.

CONCLUSIONS

These data indicate that ovarian cancers demonstrate differential sensitivity to ASOs targeted against Raf-1, and target expression levels and degree of utilization of Raf-1 signaling are implicated. Clinically sensitive tumors could feasibly be identified.

Repeated inadvertent endobronchial intubation during laparoscopy

Inadvertent endobronchial intubation occurred twice during laparoscopic surgery, with two different causes. Radiography was the only means of definitive diagnosis.

Insulin-treated diabetes and driving in the UK

Diabetes, and particularly insulin-treated diabetes, has important implications for motor vehicle driving, largely because of its association with potential hypoglycaemia. For this reason, most countries operate some driving restrictions on insulin-treated diabetic patients, as well as systems of intermittent reassessment of hypoglycaemic risk. In the UK, regulations are operated by the Driver and Vehicle Licensing Agency (DVLA), which is an agency of the Department of the Environment, Transport and the Regions (DETR). They are supported by an Expert Panel which advises the Secretary of State on diabetes-related issues relating to fitness to drive. The patient organization Diabetes UK is also concerned with diabetes and driving issues, largely from a position of lobbying policy-influencers and supporting individual cases. All parties involved with diabetes and driving issues recognize the need for more research on the subject, as the current literature is flawed in design, though no convincing excess of accidents amongst diabetic drivers has been conclusively demonstrated. Currently in the UK, Class 2 vehicles (large trucks and passenger vehicles) are barred to diabetic drivers on insulin. European law has recently extended this to so-called C1 (large vans and small lorries) and D1 (minibuses) vehicles, though the law has recently been revised to allow individual consideration for potential diabetic C1 drivers on insulin treatment. Diabetes and insulin-treated diabetes is an emotive and difficult issue, for which a stronger evidence base is urgently needed.

Multiple lysosomal trafficking phenotypes in metastatic mouse mammary tumor cell lines

Although altered synthesis and trafficking of lysosomal proteins and their receptors are associated with a wide range of human and rodent malignancies, the basis for their involvement remains obscure. Here we describe findings on a set of mouse mammary tumor cell lines that we are using as a model to study the role of these proteins in oncogenesis and tumor progression. Three distinct proteinase-secreting phenotypes were identified among the metastatic cell lines of the set. Two phenotypes displayed a high level of secretion of cathepsin L and the third was characterized by elevated secretion of matrix metalloproteinase 9 (MMP-9). The two cathepsin L-secreting phenotypes were distinct in that they displayed differences in cathepsin trafficking, expression of mannose 6-phosphate/insulin-like growth factor receptor and expression of proliferin, a mannose-phosphorylated angiogenic factor. Although cells representing all three phenotypes are capable of dissemination to distant organs when implanted into mouse mammary glands, only cells with the MMP-9 phenotype were found to be capable of direct intravasation. These findings indicate that multiple proteinase-secreting phenotypes can arise from the same tumor and suggest that cathepsin L and other lysosomal proteins may play a role in dissemination of tumor cells via the lymphatic system.

Plant-derived estrogens relax coronary arteries in vitro by a calcium antagonistic mechanism

OBJECTIVES

To investigate the potential for plant derived estrogens (phytoestrogens) genistein, phloretin, biochanin A and zearalanone to relax rabbit coronary arteries in vitro and to determine the mechanism(s) of such relaxation.

BACKGROUND

Epidemiological data suggests a reduction in the incidence of coronary heart disease in humans who have a high intake of phytoestrogens.

METHODS

Isolated rabbit coronary artery rings were suspended in individual organ baths, precontracted with potassium chloride (30 mM), and the relaxing effects and mechanisms of relaxation to genistein, phloretin, biochanin A and zearalanone were determined by measurement of isometric tension.

RESULTS

Genistein, phloretin and biochanin A induced significant gender-independent relaxation in rings with and without endothelium. Inhibition of nitric oxide and prostaglandin synthesis with L-NAME and indomethacin had no effect on genistein-induced relaxation. Relaxation was unaffected by the specific estrogen receptor antagonist ICI 182,780, the ATP-sensitive potassium channel inhibitor glibenclamide and the potassium channel inhibitor, barium chloride. Calcium concentration-dependent contraction curves in high potassium depolarization medium were significantly shifted to the right and downward after incubation with genistein and zearalanone. An inhibitory effect of genistein (2 microM) on L-type calcium current in guinea-pig ventricular myocytes confirmed a calcium antagonist relaxing mechanism of action. In healthy volunteers, plasma genistein levels of approximately 2 microM are achieved after ingestion of a commercially available soy protein drink (Supro) containing 37 mg genistein.

CONCLUSIONS

This study demonstrates that phytoestrogens induce endothelium-independent relaxation of coronary arteries; the mechanism involves calcium antagonism. These mechanisms may contribute to the potential long-term cardiovascular protective effect of these substances.

Mucosal immunity in extrinsic allergic alveolitis: salivary immunoglobulins and antibody against inhaled avian antigens among pigeon breeders

BACKGROUND

Inhaled antigens from pigeons can cause extrinsic allergic alveolitis (EAA); a model disease of pulmonary inflammation. Among pigeon breeders, serum antibody and sensitized lymphocytes specific for these antigens have been described primarily, but not always, with disease. Antibody activity within the lung may have a closer association with disease, however, sampling by alveolar lavage at bronchoscopy is impractical for screening, therefore we used saliva to quantify the mucosal antibody response.

OBJECTIVE

To establish: (a) if antibody activity against inhaled avian antigens was detectable in the saliva of pigeon breeders, (b) if the distribution of saliva antibody and total immunoglobulin levels were quantitatively or qualitatively different from serum, and (c) whether the hypersensitivity symptoms of EAA were associated more with the mucosal or the systemic humoral immune response.

MEASURES

Saliva and serum total and avian antigen-specific IgG, IgA (IgA1 and IgA2) antibody activity in 87 pigeon breeders and 24 control subjects with no avian exposure. Albumin levels were used as a protein reference and cotinine levels confirmed smoking status. Specific hypersensitivity symptoms and various exposure indices to pigeons were established by interview.

RESULTS

Absolute levels and relative proportions (vs albumin) of IgG, IgA and IgA1 in saliva, and IgG in serum, were significantly higher in pigeon breeders compared with controls, suggesting mucosal inflammation. Avian antigen-specific antibody of all isotypes was readily demonstrable in saliva (predominantly IgA) and serum (predominantly IgG) from pigeon breeders, and there were no significant titres in controls. The levels of IgG antibody in saliva and in serum correlated significantly (r = 0.52, P < 0.001), and both correlated with the raised immunoglobulin levels. In both saliva and serum the IgG rather than the IgA antibody activity was associated with symptoms of EAA.

CONCLUSIONS

Antibody activity in saliva and serum, representing the mucosal and systemic responses, respectively, were both strongly stimulated by inhaled antigens. The IgG antibody titres of saliva and serum correlated significantly and were a useful index of inflammation, as measured by the raised total immunoglobulin levels, and symptoms. This suggests that IgG antibody in serum may reflect clinical and immunological sensitization of the lung mucosa. Collecting saliva is noninvasive, and saliva antibody measurement is a convenient method for monitoring EAA, especially in children, and will facilitate sampling for example in epidemiological studies of antibody prevalence.

Biomarkers of oxidative stress are significantly elevated in Down syndrome

There is convincing epidemiological and in vitro evidence of chronic oxidative stress in individuals with Down syndrome (DS). These individuals develop Alzheimer like changes in the brain in their 30s and 40s. The incidence of autoimmune diseases and cataracts is significantly increased, and the overall ageing process is accelerated. In vitro studies show that impaired viability of DS neurons may be amended by simple chemical antioxidants, such as vitamin E, BHT and propyl gallate, clearly indicative of oxyl radical involvement. However, because of the lack of in vivo experiments, the role of oxidative stress in DS remains controversial. We report here on the results of the chemical analyses of urine samples of 166 individuals, where DS subjects were matched by their siblings. The levels of 8-hydroxy-2'-deoxyguanosine (2.35 +/- 1.69 in DS vs. 1.35 +/- 1.04 in controls, P = 0.00011), a biomarker of oxidative damage to DNA, and malondialdehyde (0.255 +/- 0.158 in DS vs. 0.204 +/- 0.128 in controls, P = 0.033), a biomarker of lipid peroxidation, are significantly elevated in individuals with DS. Dietary influences failed to show any significant correlation with the oxidative stress biomarkers. These results provide direct evidence for increased oxidative stress in individuals with DS.

Who reads temporal information contained across synchronized and oscillatory spike trains?

Our inferences about brain mechanisms underlying perception rely on whether it is possible for the brain to 'reconstruct' a stimulus from the information contained in the spike trains from many neurons. How the brain actually accomplishes this reconstruction remains largely unknown. Oscillatory and synchronized activities in the brain of mammals have been correlated with distinct behavioural states or the execution of complex cognitive tasks and are proposed to participate in the 'binding' of individual features into more complex percepts. But if synchronization is indeed relevant, what senses it? In insects, oscillatory synchronized activity in the early olfactory system seems to be necessary for fine odour discrimination and enables the encoding of information about a stimulus in spike times relative to the oscillatory 'clock. Here we study the decoding of these coherent oscillatory signals. We identify a population of neurons downstream from the odour-activated, synchronized neuronal assemblies. These downstream neurons show odour responses whose specificity is degraded when their inputs are desynchronized. This degradation of selectivity consists of the appearance of responses to new odours and a loss of discrimination of spike trains evoked by different odours. Such loss of information is never observed in the upstream neurons whose activity is desynchronized. These results indicate that information encoded in time across ensembles of neurons converges onto single neurons downstream in the pathway.

Spatiotemporal structure of olfactory inputs to the mushroom bodies

A requirement to understand mushroom body (MB) function is to characterize the operations (or transformations) that they impose on incoming signals. Understanding the nature of these integrative operations requires an understanding of the inputs from other brain areas. By inputs we mean not only the anatomical pathways leading to the MBs, but also the dynamic structure of the inflow of sensory (and other) signals. Neurons are complex, capacitative, and generally nonlinear devices that transform barrages of neurochemical packets into electrical waveforms. Their modes of operation are intrinsically time dependent and therefore, their functions or roles in a circuit cannot be inferred only from structural data. Thanks to elegant anatomical, behavioral, genetic, and molecular (for review, see Crittenden et al. 1998; Hammer and Menzel 1998; Heisenberg 1998; Wolf et al. 1998) studies, there is convincing evidence that MB circuits are involved, at least in fruit flies and honeybees, in some forms of odor integration and learning. In vivo electrophysiological studies of MB neurons, however, are rare and mainly restricted to individual (or small populations of) so-called extrinsic neurons, that is, those whose processes link MBs with other brain areas (Schildberger 1983, 1984; Homberg 1984; Hammer 1993; Mauelshagen 1993; Li and Strausfeld 1997). Kaulen et al. (1984) examined extracellular potentials in the MBs of bees, using current source density analysis, and more recently, Laurent and Naraghi (1994) provided a description of stimulus-evoked activity in Kenyon cells (KCs), the intrinsic neurons of the MBs, using intracellular recordings. In this short review we will summarize the recent results from our laboratory in an attempt to provide a description of the spatiotemporal structure of olfactory inputs to the MBs and their intrinsic neurons. We will focus only on the encoding of odor quality. We will then speculate on the possible role of MB circuits for olfactory processing.

Comparison of alternative buffers for use with a new live oral cholera vaccine, Peru-15, in outpatient volunteers

During development of Peru-15, a new live oral vaccine for cholera, the role of buffer needed to be evaluated. Generally, oral bacterial vaccines are acid labile and need to be administered by using a formulation which protects them from gastric acid. We compared three different buffers for use with Peru-15, including a standard bicarbonate-ascorbic acid buffer, Alka-Seltzer, and a new electrolyte-rice buffer, CeraVacx. Saline served as the control. Thirty-nine healthy adult volunteers received Peru-15 (10(8) CFU) with one of the three buffers or saline in a double-masked study. The volunteers were monitored for symptoms for 7 days after the dose, serum was tested for antibody responses by vibriocidal antibody and immunoglobulin G antitoxin enzyme-linked immunosorbent assays, and stool samples were tested for excretion of the vaccine strain. Side effects were minimal in all groups. All 30 volunteers who took Peru-15 with a buffer showed significant rises in vibriocidal antibody titer. The magnitude of the rises was higher in the CeraVacx group than in the other two buffer groups. Four of nine volunteers who took the vaccine with saline also showed increased titers, but they were lower than those in any of the three buffer groups. Excretion of the vaccine strain was similar in the buffer groups, but excretion was not associated with the magnitude of the vibriocidal responses. Excretion of Peru-15 was not detected in the saline group. We conclude that buffer does amplify the serological response to Peru-15 and that CeraVacx may provide benefits not provided by other buffers.

Distinct mechanisms for synchronization and temporal patterning of odor-encoding neural assemblies

Stimulus-evoked oscillatory synchronization of neural assemblies and temporal patterns of neuronal activity have been observed in many sensory systems, such as the visual and auditory cortices of mammals or the olfactory system of insects. In the locust olfactory system, single odor puffs cause the immediate formation of odor-specific neural assemblies, defined both by their transient synchronized firing and their progressive transformation over the course of a response. The application of an antagonist of ionotropic gamma-aminobutyric acid (GABA) receptors to the first olfactory relay neuropil selectively blocked the fast inhibitory synapse between local and projection neurons. This manipulation abolished the synchronization of the odor-coding neural ensembles but did not affect each neuron's temporal response patterns to odors, even when these patterns contained periods of inhibition. Fast GABA-mediated inhibition, therefore, appears to underlie neuronal synchronization but not response tuning in this olfactory system. The selective desynchronization of stimulus-evoked oscillating neural assemblies in vivo is now possible, enabling direct functional tests of their significance for sensation and perception.

Isolation, excessive time demands and sexism face female MDs, CMA workshop told

Networking plays a critical role in the professional development of female physicians and meetings such as a recent CMA-sponsored workshop help encourage it, physicians attending the workshop were told. Janet Bickel told the female doctors hat one of the key problems they face is overcoming structural inflexibility that does not allow a balance between personal and professional concerns: "Meetings like this one help you realize your own strengths, and get a new perspective on your expertise and values.

The response of bone to external loading regimens

The results of Hert et al. have been re-examined using an external pin fixation technique involving New Zealand White rabbits. New bone formation was assessed with tetracycline epifluorescence in 49 animals. The animals were operated upon using inhalational anaesthesia, and pins were placed at opposite ends of the tibia of both hind limbs. Following recovery, oxytetracycline was given at a dosage of 25 mg kg-1 body weight intraperitoneally on the day of loading and on the fourteenth day of the loading regimen. The bones were loaded for 45 min per 24 h. Undemineralized specimens were sectioned and standardized photographs produced. The area of new bone was determined by a planimeter and by digitization. In dynamic loading the shape of the force/time curve is of little significance; the response is frequency dependent and for higher frequencies the response is greater than that from continuous loading; there was no statistical significance between the rapid relief loading regimens. For continuous loading the response is a function of the load value. In all cases more bone is laid down in immature subjects than in adults. With regard to osteoclastic activity, all loading increased the areas of resorption irrespective of character, in all adult animals intermittent loads produced a greater area of ostoeclastic resorption than static loads and produced a greater change as the number of load cycles per minute increased. The adult control animals had more resorptive activity than the immature animals although there was no statistical significance. Loading, irrespective of its character, led to a net increase of bone, the osteoblastic effects thus outweighing the osteoclastic effects.

Pax-QNR/Pax-6, a paired- and homeobox-containing protein, recognizes Ets binding sites and can alter the transactivating properties of Ets transcription factors

We have previously isolated a cDNA clone encoding a protein with a paired- and homeodomain from MC29-transformed quail neuroretina cells that we have termed Pax-QNR. Pax-QNR is homologous to the murine Pax-6, which is mutated in the autosomal dominant mutation small eye (Sey) of the mouse and aniridia in man. The 46 kDa Pax-QNR protein binds specifically to the e5 DNA recognition sequence present upstream of the Drosophila even-skipped gene. The Pax-QNR paired and homeobox domains expressed separately in bacteria are both able to recognize this sequence. The core sequence recognized by the paired domain of Pax genes is TTCC (GGAA), and this sequence is also present in the core recognition site bound specifically by Ets family-encoded proteins. Ets proteins are a family of transcription factors sharing a highly conserved 85 amino acid DNA binding domain. In this article we demonstrate that Pax-QNR/Pax-6 expressed in reticulocyte lysate is able to specifically recognize several Ets binding sites. In addition, we found that the transactivation mediated by the p68c-ets-1 pr p55erg through the Polyomavirus enhancer sequence is specifically inhibited by the p46kDaPax-QNR in transient transfection assay.

Regulation of erythroid cell-specific gene expression during erythropoiesis

The aim of our group's work over the past few years has been to investigate the molecular mechanisms regulating erythroid cell-specific gene expression during erythroid cell differentiation. In addition to the alpha-globin gene, we have focussed on two non-globin genes of interest encoding the rabbit red cell-specific lipoxygenase (LOX) and the mouse glutathione peroxidase (GSHPX), an important seleno-enzyme responsible for protection against peroxide-damage. Characterisation of the GSHPX gene showed that the seleno-cysteine residue in the active site of the enzyme is encoded by UGA, which usually functions as a translation-termination codon. This novel finding has important implications regarding mRNA sequence context effects affecting codon recognition. The regulation of the GSHPX and red cell LOX genes has been investigated by functional transfection experiments. The 700 bp upstream of the GSHPX promoter seems to function equally well when linked to the bacterial chloramphenicol acetyl transferase (CAT) gene and transfected into mouse erythroid or fibroblast cell lines. However, the presence of tissue-specific DNase I hypersensitive sites (DHSS) in the 3' flanking region of the GSHPX gene suggests that such sites may be important in its regulation in the various cell types in which it is highly expressed, i.e., erythroid cells, liver and kidney. The transcription unit of the RBC LOX gene has also been defined and 5' and 3' flanking regions are being investigated for erythroid-specific regulatory elements: a region upstream of the LOX gene gives increased expression of a linked CAT gene when transfected into mouse erythroid cell lines compared to non-erythroid cell lines.(ABSTRACT TRUNCATED AT 250 WORDS)

A double blind placebo controlled comparison of verapamil, atenolol, and their combination in patients with chronic stable angina pectoris

The efficacy and effect on cardiac function of verapamil 120 mg three times a day and atenolol 100 mg once a day, singly and in combination, were evaluated in 15 patients with angina pectoris. While they were on the combination treatment four patients withdrew from the study. Episodes of angina pectoris and glyceryl trinitrate consumption were significantly reduced only on the combination. On the combination only four patients developed evidence of ischaemia during exercise compared with seven on verapamil and ten on atenolol. ST segment depression at peak exercise, assessed by 16 point precordial mapping, was reduced by all active treatments from 7.1 on placebo to 2.7, 0.9, and 0.6 mm on atenolol, verapamil, and the combination respectively. Mean left ventricular ejection fraction fell significantly from 60% on placebo to 53% on the combination but was unchanged on verapamil and atenolol. Verapamil was an effective alternative to atenolol; the combination was the most effective treatment but was associated with a significant morbidity.

Treatment of angina pectoris with nifedipine and atenolol: efficacy and effect on cardiac function

The antianginal effects of nifedipine 20 mg three times a day and atenolol 100 mg once a day singly and in combination were investigated in 16 patients with angina pectoris. The amount of work that could be done before angina and ST depression appeared was significantly increased by atenolol and the combination but not by nifedipine. At peak exercise the number of leads on a 16 point precordial electrocardiogram map that demonstrated greater than or equal to 1 mm ST segment depression was significantly reduced from a mean (SD) of 5.0 (0.4) on placebo to 3.7 (0.6), 2.8 (0.4), and 2.3 (0.7) on nifedipine, atenolol, and the combination respectively. Mean resting left ventricular ejection fraction, assessed by gated radionuclide ventriculography, did not change during any active treatment phase but increased significantly during exercise only on nifedipine and the combination. The nifedipine/atenolol combination was the most effective treatment, and the data suggest that nifedipine may be used to best advantage in combination with a beta blocker.

The effects of preload, after load, and epinephrine on cardiac performance in the sea raven, Hemitripterus americanus

The preparation of the in situ heart was accomplished without any physical disturbance to the heart. The heart generated an intrinsic rhythm which was steady throughout the experiment and apparently was derived from the sinoatrial pacemaker. The power output developed by the in situ heart at physiological preloads and after loads was comparable to in vivo values. The effect of increasing preload (0 to 3 cmH2O) was a fourfold increase in stroke volume with little or no change in heart rate. When after load was changed (25 to 45 cmH2O) heart rate was unchanged and stroke volume was usually maintained. As a consequence, cardiac output was maintained by intrinsic factors alone at a higher work load. Epinephrine (10−9 to 10−5 M) in the perfusate produced relatively weak positive chronotropic and inotropic effects. The increase in cardiac output produced by epinephrine was small compared with the intrinsic changes evoked when preload was raised.