Abstract P5-06-10: ErbB Signaling Is Required for Activation of Phosphatidylinositol-3 Kinase and Transformation of Mammary Epithelial Cells by Polyomavirus Middle T Antigen

Summary

Polyomavirus middle T (PyVmT) transforms cells through phosphatidylinositol 3-kinase (PI3K). Overexpression of ErbB2/ErbB3 heterodimers, potent activators of PI3K, occurs in PyVmT-driven mouse mammary tumors, but without known cause and consequence. Inhibition of ErbB2 with lapatinib, or genetically engineered loss of ErbB3, decreased PI3K signaling and tumor growth in mice, suggesting ErbB2/ErbB3 is required by PyVmT. ErbB2/ErbB3 formed signaling complexes containing PyVmT, p85 and Src. EZN-3920, a novel high-affinity oligonucleotide targeting ErbB3 transcripts, impaired ErbB3 expression in vivo, decreased PI3K signaling, cell survival, and growth of tumors, and improved response to lapatinib. Therefore, PyVmT utilizes ErbB2/ErbB3 overexpression to drive PI3K signaling. Furthermore, the challenge of ErbB3 as a kinase-inactive therapeutic target can be overcome by targeting ErbB3 mRNA transcripts in vivo. Significance

Given the widespread use of, and knowledge gained from the MMTV-PyVmT transgenic mouse breast cancer model, understanding how PyVmT utilizes existing cell signaling programs is necessary to interpret how results impact our understanding/treatment of human breast cancers. We found that ErbB2/ErbB3 heterodimers were a necessary part of PyVmT signaling complexes involving Src and PI3K, and that PyVmT depends on ErbB3 in the breast epithelium for PI3K activity and tumor growth. Because ErbB3 harbors a weak/inactive tyrosine kinase, therapeutic anti-ErbB3 interventions present with challenges. Further, anti-ErbB3 antibodies that block ligand interaction with ErbB3 do not alter ligand-independent ErbB3 signaling. However. these challenges were overcome using high-affinity oligonucleotides targeting ErbB3 mRNA. Use of the oligonucleotide EZN-3920 effectively reduced ErbB3 expression, inhibited PyVmT tumor growth, and improved the response of tumors to lapatinib. These results support oligonucleotide knock-down of targets as potential therapeutic strategy.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P5-06-10.

Transcriptional and Post-Translational Upregulation of HER3 (ErbB3) Counteracts Antitumor Effect of HER2 Tyrosine Kinase Inhibitors

We hypothesized that sustained inhibition of HER3 and its output to PI3K/Akt is required for the optimal antitumor effect of HER2 inhibitors. Therefore, we examined the temporal effect of the HER2 tyrosine kinase inhibitor (TKI) lapatinib (lap) on feedback upregulation of active HER3 in HER2-overexpressing breast cancer cells. A time course with lap-treated cells showed 3 to 5-fold upregulation of HER3 RNA and protein, beginning at 4 h and increasing through 48 h. P-Tyr immunoblot of HER3 immunoprecipitates revealed recovery of HER3 phosphorylation at and beyond 13 h of treatment. Site-specific antibodies revealed HER3 phosphorylation at Y1197 and Y1289, two of the six p85 binding sites in HER3. Recovery of P-HER3 correlated temporally with recovery of T308 P-Akt. The upregulation of HER3 RNA upon treatment with lap suggested that inhibition of active HER2 and PI3K/Akt derepresses the transcription factor FoxO3a. Putative FoxO3a binding sites were identified within the 5' flanking region upstream of the HER3 transcription start site. Transfection with FoxO3a siRNA reduced basal and lap-induced HER3 RNA levels 2 to 5-fold compared to control cells. Conversely, overexpression of FoxO3a increased HER3 RNA 2.5-fold, which could be further enhanced by lap treatment. In addition to these transcriptional mechanisms, the recovery of P-HER3 upon lap-induced inhibition of HER2 suggested engagement of another tyrosine kinase transactivating HER3 and/or that HER2 had been incompletely inhibited by the TKI. However, IGF-IR, Src, and MET TKIs did not inhibit the recovery of P-HER3. On the other hand, the addition of trastuzumab (tz) to lap-treated cells prevented recovery of P-HER3, suggesting that disruption of a ligand-independent HER2-HER3 interaction was involved in partial maintenance of HER3 phosphorylation.The upregulation of HER3 RNA and partial maintenance of P-HER3 and P-Akt suggested that combined inhibition of HER2 and HER3 will synergistically inhibit tumor cell viability. Transfection with HER3 siRNA sensitized HER2+ breast cancer cells to each lap and tz as assessed by Apo-BrdU (apoptosis) and 3D-Matrigel growth assays. Further, treatment with AMG-888, a HER3 monoclonal antibody (AMGEN-U3), sensitized cells to each lap and tz. Ongoing studies include the treatment of BT474 xenografts in athymic mice with lap ± AMG-888 using [18F]-FDG-PET as a non-invasive imaging biomarker to predict treatment outcome. Finally, we examined HER3 levels by immunohistochemistry in sections from tumor blocks of patients enrolled in a neoadjuvant trial where lap was given alone during the first 6 weeks of therapy. The percent and intensity of tumor cell staining was calculated as a histoscore (Human Pathol. 26:291, 1995). On week 2 of therapy, HER3 levels increased 135% above pre-therapy levels (n=8; p=0.03, Mann-Whitney). These data suggest that upon inhibition of the HER2 tyrosine kinase, HER2+ breast cancers 1) upregulate HER3 by transcriptional mechanisms and partially maintain HER3 function by post-translational mechanisms; 2) this compensatory phosphorylation of HER3 partially maintains PI3K/Akt; and 3) inhibition of HER3 sensitizes HER2-dependent breast cancer cells to HER2 inhibitors.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 63.

A survey of respiratory and sleep services in New Zealand undertaken by the Thoracic Society of Australia and New Zealand (TSANZ)

AIMS

In 2004, the NZ Branch of the TSANZ published "Standards for Adult Respiratory and Sleep Services" on the Ministry of Health's (MoH) website.1 The aim of this survey was to evaluate each of the 21 District Health Boards' (DHBs) performance against the published standards, concentrating particularly on staffing, infrastructure, clinical support services, implementation of guidelines, quality assurance activity, and basic services (sleep, lung function, and oxygen).

METHODS

Postal questionnaire survey of all DHBs in late 2006.

RESULTS

All 21 DHBs responded. Only 10 of 21 DHBs were complying with the minimum standards of care. Main deficiencies in care related to: inadequate medical staffing rates, lack of quality assurance measures and insufficient laboratory testing (sleep and lung function). The lack of monitoring of such basic activities as outpatient clinic attendances, oxygen and sleep services, and the non implementation of treatment guidelines were of particular concern. Seven-fold variations in prescription of assisted ventilation equipment and oxygen therapy exist across the country.

CONCLUSIONS

When evaluated against minimum standards of care published in 2004, major gaps in service provision exist in New Zealand. Access to services is variable. There is a lack of national leadership and insufficient regional organisation leading to large gaps in service provision of even basic respiratory services. Immediate changes to the current service provision structures are required.

Characterization of formulated microbial products by denaturing gradient gel electrophoresis, total cellular fatty acid analysis, and DNA microarray analysis

Two commercial products, Biotize and Cycle, containing bacteria as an active ingredient were characterized for species identification and batch-to-batch variation by denaturing gradient gel electrophoresis (DGGE), total cellular fatty acid analysis (FAA), and a taxonomic DNA microarray. DGGE was useful at assessing the stability of consortia in different batches, and cluster analysis differentiated each batch even when only slight differences in species composition were observed. DGGE, FAA, and DNA microarray results indicated little batch-to-batch variation in Biotize and some batch variation in Cycle. The 3 methods agreed well with species identification in Biotize but generated conflicting results in the species composition of Cycle. This multi-method approach was useful in determining if the observed bacterial species present in the products matched the expected species composition.

Prevalence of Giardia in symptomatic dogs and cats throughout the United States as determined by the IDEXX SNAP Giardia test

National prevalence of Giardia infection in dogs and cats presenting to clinics with vomiting and/or diarrhea was examined using the IDEXX SNAP Giardia test kit. Veterinary practices across the United States were sent an invitation to participate in the survey and asked to use the test on fecal samples from the target population. The survey requested that the clinics report the results of 20 or more tests. A total of 21,092 results were reported, comprised of 16,114 dogs and 4,978 cats. Analysis of the data (excluding the handful of results reported from Puerto Rico) showed a Giardia prevalence of 15.6% among dogs tested, and 10.8% among cats. This difference was statistically significant (p < 0.001). Regional categorization into Northeast, Southeast, West, and Midwest drew out significant (p < 0.001) differences in prevalence in most cases for dogs; the differences were not significant for cats. These differences and other variables are currently being examined with this and additional data sets. We conclude on the basis of the SNAP test diagnostic that Giardia is a common enteric agent among dogs and cats with gastrointestinal signs.

Allergic bronchopulmonary aspergillosis in a lung transplant patient successfully treated with nebulized amphotericin

A case of allergic bronchopulmonary Aspergillosis (ABPA) complicating lung transplantation for cystic fibrosis is described. Control of ABPA was only achieved with 20 mg of prednisone and 600 mg of itraconazole per day. However, a prompt clinical and physiologic response was observed when nebulized amphotericin was introduced, which allowed prednisone to be reduced to 7.5 mg per day and, in time, all anti-fungal therapy to be withdrawn.

Management of solitary pulmonary nodules: how do thoracic computed tomography and guided fine needle biopsy influence clinical decisions?

BACKGROUND

Computed tomography (CT) and fine needle guided biopsy (FNB) are often used in the assessment of patients with lung nodules. The influence of these techniques on clinical decision making has not been quantified, especially for small solitary pulmonary nodules (SPN) where the probability of malignancy is lower. A study was undertaken to determine the effect of CT and FNB derived information on clinical decision making in patients with a solitary pulmonary nodule < or = 3 cm in diameter on initial chest radiography.

METHODS

Clinical, physiological, and outcome data on 114 patients with an SPN < or = 3 cm who had subsequent thoracic CT and FNB were extracted from the records of a specialist cardiorespiratory hospital in Auckland, New Zealand. Chest radiographs and CT scans were reported according to specified criteria by a thoracic radiologist. Computer generated summary sheets were used to present cases to each of six clinicians. Each case was presented three times: (1) with clinical data and chest radiograph only; (2) with the addition of the CT report; and (3) with all data including the result of the FNB. Clinicians were asked to specify their management on each occasion and to estimate the probability of the lesion being malignant. Reproducibility was assessed by re-evaluating 24 cases 1 month later.

RESULTS

33 (29%) nodules were benign, 35 (31%) nodules (malignant) were resected with negative node sampling, and 46 (40%) had a non-curative outcome (radiotherapy, incomplete resection, refused therapy). Intra-clinician decision making was consistent for all three levels of clinical data (median kappa values 0.79-0.89). Agreement between clinicians on the need for surgery was lowest with chest radiography alone (kappa=0.33), rose with CT information (kappa=0.44), and increased further with the addition of the FNB data (kappa=0.57). The proportion of successful decisions on surgical intervention (against the known outcome) increased with the addition of CT reports and further with FNB reports (p=0.006, Friedman's test). The major benefit of the information added by CT and FNB reports was a reduction in unnecessary surgery, especially when the clinical perception of pre-test probability of malignancy was intermediate (31-70%). FNB data contributed most to the benefit (p<0.001). The addition of CT and FNB was cost efficient and can be applied specifically to patients with a low or intermediate probability of malignancy.

CONCLUSION

Both CT and FNB make cost effective contributions to the clinical management of SPN < or = 3 cm in diameter by reducing unnecessary operations and increasing agreement between physicians on the need for surgery.

Management of solitary pulmonary nodules: how do thoracic computed tomography and guided fine needle biopsy influence clinical decisions?

BACKGROUND

Computed tomography (CT) and fine needle guided biopsy (FNB) are often used in the assessment of patients with lung nodules. The influence of these techniques on clinical decision making has not been quantified, especially for small solitary pulmonary nodules (SPN) where the probability of malignancy is lower. A study was undertaken to determine the effect of CT and FNB derived information on clinical decision making in patients with a solitary pulmonary nodule < or = 3 cm in diameter on initial chest radiography.

METHODS

Clinical, physiological, and outcome data on 114 patients with an SPN < or = 3 cm who had subsequent thoracic CT and FNB were extracted from the records of a specialist cardiorespiratory hospital in Auckland, New Zealand. Chest radiographs and CT scans were reported according to specified criteria by a thoracic radiologist. Computer generated summary sheets were used to present cases to each of six clinicians. Each case was presented three times: (1) with clinical data and chest radiograph only; (2) with the addition of the CT report; and (3) with all data including the result of the FNB. Clinicians were asked to specify their management on each occasion and to estimate the probability of the lesion being malignant. Reproducibility was assessed by re-evaluating 24 cases 1 month later.

RESULTS

33 (29%) nodules were benign, 35 (31%) nodules (malignant) were resected with negative node sampling, and 46 (40%) had a non-curative outcome (radiotherapy, incomplete resection, refused therapy). Intra-clinician decision making was consistent for all three levels of clinical data (median kappa values 0.79-0.89). Agreement between clinicians on the need for surgery was lowest with chest radiography alone (kappa=0.33), rose with CT information (kappa=0.44), and increased further with the addition of the FNB data (kappa=0.57). The proportion of successful decisions on surgical intervention (against the known outcome) increased with the addition of CT reports and further with FNB reports (p=0.006, Friedman's test). The major benefit of the information added by CT and FNB reports was a reduction in unnecessary surgery, especially when the clinical perception of pre-test probability of malignancy was intermediate (31-70%). FNB data contributed most to the benefit (p<0.001). The addition of CT and FNB was cost efficient and can be applied specifically to patients with a low or intermediate probability of malignancy.

CONCLUSION

Both CT and FNB make cost effective contributions to the clinical management of SPN < or = 3 cm in diameter by reducing unnecessary operations and increasing agreement between physicians on the need for surgery.

A child with Miller Fisher syndrome

We describe the case of a six-year-old girl who presented with a 3-day history of diplopia and gait disturbance following a febrile flu-like illness. On examination she was found to have ataxia, areflexia and ophthalmoplegia, and a diagnosis of Miller Fisher syndrome was made after the exclusion of other conditions. This report outlines the frequency of Miller Fisher syndrome and lists the differential diagnoses that should be considered in Australia. In addition, the occurrence of pupillary dysfunction is discussed.

Case-control study of severe life threatening asthma (SLTA) in adults: psychological factors

BACKGROUND

Severe life threatening asthma (SLTA) is important in its own right and as a proxy for asthma death. In order to target hospital based intervention strategies to those most likely to benefit, risk factors for SLTA among those admitted to hospital need to be identified. Adverse psychological factors are purported risk factors for asthma death and SLTA /near fatal asthma. A study was undertaken to determine whether, in comparison with patients admitted to hospital with acute asthma, those with SLTA have specific adverse psychological factors.

METHODS

A case-control study was undertaken. Cases (n=77) were admitted to the intensive care unit with SLTA (mean (SD) pH 7.17 (0.15), PaCO(2) 10.7 (5.0) kPa). Controls (n=239) were admitted to general wards with acute asthma and were matched only by date of index attack. An interviewer administered questionnaire was undertaken 24-48 hours after admission. A random sample of community based asthmatics was recruited to provide normative data on asthmatics for comparison with cases and hospital controls.

RESULTS

The risk of SLTA increased with age (OR 1.04/year, 95% CI 1.01 to 1.07) and was less for women (OR 0.36, 95% CI 0.20 to 0.68). These variables were controlled for in all further analyses. There was a high prevalence of psychological disorder in both cases and matched controls, but there was no difference in prevalence of caseness for anxiety or depression, total (or individual) life events in last 12 months, availability of general or disease specific social support, nor in any of the domains of the Attitudes and Beliefs about Asthma Questionnaire (emotional (mal) adjustment, doctor-patient relationship, stigma, self-efficacy). Cases (SLTA) were less likely to have had previous emotional counselling (25% v. 35%, p<0.05). However, when comparison was made with a community based group of asthmatic patients, those admitted to hospital with acute asthma (SLTA and hospital controls) had a higher prevalence of anxiety and depression, higher total life events, and higher prevalence of certain specific life events.

CONCLUSIONS

There was considerable psychological morbidity generally (and anxiety specifically) in those admitted with acute asthma. Specific adverse psychological factors were not risk factors for SLTA, when comparison was made with those admitted to hospital with acute asthma, but adverse psychological factors were a risk factor for hospitalisation for acute asthma (including SLTA). Psychological risk factors for adverse events in asthma are dependent both on the type of event under study and the comparison group used.

Normal midtrimester (17-20 weeks) genetic sonogram decreases amniocentesis rate in a high-risk population

OBJECTIVE

To evaluate a screening protocol using advanced maternal age, triple-marker screening, and genetic sonography.

METHODS

We compared adverse chromosomal outcomes of pregnancy in 1556 women referred for increased risk of aneuploidy because of either advanced maternal age or triple-marker test results. Patients were counseled about the results of the triple-marker test and subsequent sonography, which led to a patient decision of whether to pursue amniocentesis. Fetal measurements and structural abnormalities were compared with chromosomal findings. When patients elected amniocentesis, karyotypes were obtained.

RESULTS

Genetic sonography reduced the rate of amniocentesis by 61% overall and by 40% when compared with an alpha-fetoprotein profile alone. The sensitivity of sonography combined with the triple-marker screen for the detection of trisomy 21 was 87% compared with 91% for the triple-marker screen alone.

CONCLUSIONS

This study confirmed that sonographic findings in a targeted population, in combination with other risk markers (advanced maternal age and triple-marker screening), can be used to assess the risk of aneuploidy. Biometry provides additional information for assessing the risk of aneuploidy. Combining advanced maternal age, serum triple-marker screening, and sonographic screening may provide better risk prediction for use in clinical counseling.

Synthesis, anticonvulsant properties and pharmacokinetic profile of novel 10,11-dihydro-10-oxo-5H-dibenz/b,f/azepine-5-carboxamide derivatives

A series of novel derivatives of oxcarbazepine (5), 10,11-dihydro-10-oxo-5H-dibenz/b,f/azepine-5-carboxamide was synthesised and evaluated for their anticonvulsant activity and sodium channel blocking properties. The oxime 8 was found to be the most active compound from this series, displaying greater potency than its geometric isomer 9 and exhibiting also the highest protective index value. Importantly, the metabolic profile of 8 differs from the already established dibenz/b,f/azepine-5-carboxamide drugs such as 1 and 5 which undergo rapid and complete conversion in vivo to several biologically active metabolites. In contrast 8 is metabolised to only a very minor extent leading to the conclusion that the observed anti-convulsant effect is solely attributable to 8. It is concluded that 8 may be as effective as 1 and 5 at controlling seizures and that the low toxicity and consequently high protective index should provide the compound with an improved side-effect profile.

Lung volume reduction surgery: the Thoracic Society of Australia and New Zealand

Lung volume reduction surgery involves the removal of emphysematous lung tissue with the aim of palliating symptoms in selected patients with severe emphysema. This form of surgery is being practised in Australia with favourable short-term outcomes, similar to those reported in the literature. Large multicentre trials are currently underway in North America and the United Kingdom to clarify issues of safety and long-term efficacy. As a result, it is too early to apply an evidence-based approach to this procedure. In the meantime, local audits of practice need to be undertaken to define patient subgroups at higher risk of morbidity and mortality.