Abstract OT2-09-01: Pilot study of denosumab in BRCA1/2 mutation carriers scheduling for risk-reducing salpingo-oophorectomy

Background: Denosumab is a monoclonal antibody that inhibits RANKL and is approved for the prevention of fractures in patients with osteoporosis or bone metastases. The RANKL signaling pathway is also involved in BRCA1-associated mammary tumorigenesis via a progesterone-induced paracrine effect of RANKL on luminal progenitor cells. Pre-clinical studies have demonstrated that RANKL inhibition resulted in reduced proliferation of mammary tumors. Early findings from an ongoing pre-surgical study demonstrated that denosumab treatment resulted in decreased Ki67 proliferation index in benign breast tissue. Based on these data, denosumab is being pursued as a potential preventive agent for breast cancer in BRCA1 mutation carriers. While promising, the effect of RANKL inhibition on gynecologic tissues such as the ovaries and fallopian tubes, in which progesterone has a protective effect, is unknown.

Trial design: We will conduct a multicenter, open-label randomized pilot study of presurgical administration of denosumab versus no treatment in premenopausal women with BRCA1/2 mutations undergoing risk-reducing salpingo-oophorectomy (RRSO). A total of 60 women will be randomized 1:1 to Arm 1) 3-4 doses of 120 mg denosumab subcutaneously every 4 weeks or Arm 2) No treatment. Participants will be stratified by 1) BRCA1 versus BRCA2 mutation status and 2) Use of hormonal contraceptives within the past 3 months (yes/no). Assuming a 10% unevaluable rate, we expect to have 54 evaluable participants (27 per arm).

Eligibility criteria: 1) Premenopausal women (defined as < 3 months since last menstrual period OR serum follicle-stimulating hormone (FSH) < 20 mIU/mL), age > 18 years; 2) Documented germline pathogenic mutation or likely pathogenic variant in the BRCA1 or BRCA2 gene; 3) Plan for RRSO with or without hysterectomy; 4) ECOG performance status ≤ 1 (Karnofsky ≥ 70%); 5) Normal organ and marrow function; 6) Negative pregnancy test and use of adequate contraception; 7) Willingness to take supplemental oral calcium and vitamin D3; 8) Dental examination within 6 months of enrollment and no evidence of active dental issues; 9) Ability to understand and willingness to provide informed consent.

Specific aims: Our primary objective is to compare the effect of denosumab to no treatment on Ki67 expression in the fimbrial end of the fallopian tube. Secondary objectives are to assess Ki67 in ovary and endometrium; cleaved caspase-3, RANK/RANKL, ER/PR, CD44, and STAT3/pSTAT3 expression in fallopian tube, ovary, and endometrium; gene expression profiling in the fallopian tube and ovary; serum markers (progesterone, estradiol, C-terminal telopeptide) and denosumab levels; and toxicity.

Statistical methods: The primary endpoint is post-treatment Ki67 expression in the fimbrial end of the fallopian tube in the denosumab arm compared to the no treatment arm. Assuming a standard deviation of 5.0%, we will have 82% power to detect a 4.0% absolute difference (or effect size of 0.8) in Ki67 proliferation index between the denosumab and no treatment groups by applying a 2-sample t-test at a 0.05 significance level.

Target accrual: 60 participants, to be activated in Summer 2018.

Citation Format: Trivedi MS, Samimi G, Wright JD, Holcomb K, Garber JE, Horowitz NS, Arber N, Friedman E, Wenham RM, House M, Parnes H, Lee JJ, Abutaseh S, Vornik LA, Heckman-Stoddard BM, Brown PH, Crew KD. Pilot study of denosumab in BRCA1/2 mutation carriers scheduling for risk-reducing salpingo-oophorectomy [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 OT2-09-01.

Abstract OT2-09-02: A phase I dose escalation study of topical bexarotene in women at high risk for breast cancer

Background: Breast cancer prevention with anti-estrogens, including tamoxifen, raloxifene, and exemestane, has been shown to reduce the incidence of hormone receptor-positive breast cancer. However, agents that can reduce the incidence of hormone receptor negative breast cancer are currently lacking. Rexinoids such as bexarotene are vitamin A analogues that have been shown to be involved in cell differentiation, growth, and apoptosis. In preclinical mouse models that develop ER-negative breast cancers, bexarotene showed a significant reduction in mammary tumor development. Oral bexarotene has been evaluated in BRCA mutation carriers and significant decreases in cyclin D1 were noted in breast cells suggesting biological activity of bexarotene on breast tissue. Systemic side effects of hyperlipidemia and hypothyroidism were also found. Data from chemoprevention studies with topical 4-hydroxytamoxifen support the concept of topical agents penetrating into the breast tissue and exhibiting biological activity in the tissue. We hypothesize that topical bexarotene can be applied to the breast as a chemoprevention agent with penetration to the breast tissue without subsequent systemic side effects and toxicity as seen with oral bexarotene.

Trial Design: Women at high risk for breast cancer will be recruited and assigned to one of three different dose levels: 10mg (1ml) every other day, 10mg (1ml) daily, 20mg (2ml) daily to one unaffected breast for 4 weeks. The primary endpoint of the study is to determine the recommended phase II dose of topical bexarotene 1% gel for evaluation in healthy at-risk women. Dose Limiting Toxicity (DLT) is defined as a grade 2 skin adverse event that persists for at least 6 days or any grade 3 or greater adverse event related to the study drug. A grade 2 skin adverse event that recurs and persists for at least 3 days is also a DLT. The Maximum Tolerated Dose (MTD) will be defined as the highest dose level at which no more than 2 participants experience a DLT among 10 participants treated. A conservative modification of the standard “3+3” design will be applied. The first three participants will be assigned to the lowest dose level. New cohorts of 3-4 participants will not be treated until toxicity has been fully evaluated for all current participants through 4 weeks. Once the MTD has been determined, an expansion cohort of an additional 10 patients will be recruited at the MTD to further evaluate safety and toxicity at this dose level as well bexarotene concentration in the breast tissue. Secondary endpoints include serum bexarotene level, tissue bexarotene levels, and changes in thyroid function tests, lipid profile, and calcium. The planned accrual for this study if maximally accrued to all dose levels and the dose expansion cohort will be 40 participants.

Citation Format: Thomas PS, Patel AB, Contreras A, Liu DD, Lee JJ, Khan S, Vornik LA, Dimond EP, Perloff M, Heckman-Stoddard BM, Brown PH. A phase I dose escalation study of topical bexarotene in women at high risk for breast cancer [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 OT2-09-02.

Abstract PD3-07: A phase II pre-surgical trial of lapatinib for the treatment of women with HER2 positive or EGFR positive ductal carcinoma in situ

Background: Estrogen receptor (ER)-negative tumors and human epidermal growth factor 2-Neu (HER2) positive breast cancers are known to be more clinically aggressive subtypes of breast cancer and account for 30% of all breast cancers. Women with HER2 + breast cancers, whether ER+ or ER -, require cytotoxic chemotherapy with a HER2-targeting agent, and often have adverse outcomes. Thus, preventive agents are needed to reduce the incidence of these subtypes of aggressive breast cancer. Lapatinib, a dual tyrosine kinase inhibitor, inhibits epidermal growth factor receptors (EGFR) and HER2 kinases and has shown to decrease breast cell proliferation in invasive breast cancer and adjacent premalignant lesions. Therefore, we conducted a multi-institutional randomized Phase II clinical trial to study the effects of the signal transduction inhibitor lapatinib in women with HER2-positive or EGFR-positive ductal carcinoma in situ (DCIS).

Methods: Randomized participants received either lapatinib (750mg, 1000mg, or 1500mg) or placebo daily for 2-6 weeks prior to their surgery. After minimal accrual, the trial was later amended to lapatinib 1000mg or placebo. Pre-treatment breast tissue was obtained from initial diagnostic core biopsy and post-treatment breast tissue was obtained from surgical excision specimen. Blood was obtained prior to surgery to assess serum lapatinib level. Participants kept a daily symptom assessment log and had a cardiac assessment at baseline and prior to surgery. Patients were instructed to take drug up to and including the day before surgery. The dual primary endpoint for this study was change in proliferation in pre- versus post-treatment biopsies between the two treatment arms, as measured by Ki67 as well as toxicity assessment. Secondary endpoints included incidence of DCIS at surgery and modulation of tissue biomarker expression in growth factor receptors (EGFR, ErbB2); phosphorylated growth factor receptor (phospho-ErbB2); signal transduction markers (MAPK, phospho-MAPK); hormone receptors (ER, PR); and p27.

Results:Twenty-two women (mean age: 51; range: 32-66) with HER2+ or EGFR+ DCIS were treated with lapatinib (1,000 or 1,500 mg) or placebo for 2–6 weeks prior to surgical excision. Ki67 expression was significantly decreased in the lapatinib treatment arms compared to placebo (p=0.0122). Diarrhea, fatigue, and skin reactions were notable adverse events that occurred predominately in the lapatinib arm compared to placebo. No grade 3 or 4 events related to the study drug were noted during the study. No changes were noted in cardiac function. DCIS was present in all surgical specimens in both arms. Invasive breast cancer was noted in 1 patient on lapatinib 1000mg and 3 patients on placebo. No statistically significant changes were noted in signal transduction biomarkers

Conclusion:These results demonstrate the effectiveness of lapatinib in reducing proliferation in women with EGFR+ or HER2+ DCIS. Even low-grade toxicities can deter use of an agent in the prevention setting. This and the lack of a risk model for HER2+ and triple negative breast cancer make the development of larger scale clinical prevention trials of lapatinib for the prevention a challenge.

Citation Format: Thomas PS, Contreras A, Pruthi S, Krontiras H, Rimawi M, Garber J, Wang T, Hilsenbeck SG, Vornik LA, Gilmer T, Friedman R, Heckman-Stoddard BM, Dunn B, Kuerer H, Brown PH. A phase II pre-surgical trial of lapatinib for the treatment of women with HER2 positive or EGFR positive ductal carcinoma in situ [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 PD3-07.

Abstract P5-15-02: Withdrawn

This abstract was withdrawn by the authors.

Abstract OT3-01-04: VADIS trial: Phase II trial of the nelipepimut-S peptide v accine in women with DCIS of the breast

Background: Our group has been investigating vaccination strategies in breast cancer. Specifically, we have been evaluating HER2-derived peptide vaccines including nelipepimut-S+GM-CSF administered adjuvantly to breast cancer patients who have been rendered disease-free with standard of care therapy but are at high risk for recurrence. Early phase clinical trials showed an approximately 50% reduction in relative recurrence risk in vaccinated patients. Based on these data, nelipepimut-S+GM-CSF is being evaluated in a phase III registration trial. Having shown the vaccine to be safe, effective in stimulating an antigen-specific immune response and potentially having clinical efficacy in the setting of secondary prevention, the current study was initiated to evaluate vaccination in DCIS patients. This trial represents an initial step to move the vaccine into the primary prevention setting.

Trial Design: Phase II, randomized, single-blind study. Patients will be randomized 2:1 to receive vaccine or GM-CSF alone. After enrollment, patients will receive 3 inoculations administered every other week preoperatively followed by surgery then completion of the vaccination series (3 additional inoculations) in the adjuvant setting.

Eligibility: The trial will enroll pre- or post-menopausal women with a diagnosis of DCIS made by core biopsy. The area of radiographic abnormality must measure at least 1 cm. Because the vaccine is a MHC class I, CD8+ T cell-eliciting vaccine, it is HLA restricted, and patients must be HLA-A2+ to enroll. Participants must also have an ECOG performance status <2, adequate cardiac, kidney and liver function and be willing to comply with all study interventions and follow-up procedures.

Specific Aims: The trial's primary endpoint is to evaluate for nelipepimut-specific CD8+ T cells in the peripheral blood of vaccinated patients compared to patients receiving GM-CSF alone. Secondary endpoints include evaluating toxicity; determining the immune response in vivo by DTH, in vitro by evaluating for epitope spreading to other tumor antigens, and importantly in the tumor by assessing the degree of lymphocytic infiltration in surgically resected specimens. The extent of HER2 expression, Ki67 and cleaved caspase 3 in the resected specimen will also be assessed.

Statistical Methods: A total of 108 DCIS patients will be consented and screened for eligibility. 48 (45%) are expected to be HLA-A2 positive. These 48 patienst will be randomized 2:1 to vaccine or GM-CSF alone groups. Accounting for 10% attrition rate and for an approximately 5% non-evaluable sample rate, we expect to have 40 evaluable patients, 27 in the vaccine group and 13 in the GM-CSF alone group, that have baseline, pre-surgery, and post-surgery measures of nelipepimut-S-specific CD8+ T cells. We will have 82% power to detect a significant increase in nelipepimut-S-specific CD8+ T cells in the vaccine group versus the GM-CSF alone group.

Contact Info: The study is accruing at four sites to include Columbia University, Dana Farber Cancer Institute, MD Anderson Cancer Center and Memorial Sloan Kettering Cancer Center. Additional information can be obtained from the overall study PI, Dr. Elizabeth Mittendorf (eamitten@mdanderson.org). NCT0236582.

Citation Format: Mittendorf EA, Plitas G, Garber J, Crew K, Heckman-Stoddard B, Wojtowicz M, Vornik L, Peoples GE, Brown PH. VADIS trial: Phase II trial of the nelipepimut-S peptide vaccine in women with DCIS of the breast [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr OT3-01-04.

Abstract P3-07-07: Inhibition of death-associated protein kinase 1 enhances chemotherapy action against triple-negative breast cancer

Background: Triple negative breast cancers (TNBCs) are the most aggressive ER negative breast cancers with limited therapy strategies and poor prognosis. P53 gene is frequently mutated in approximately 80% of TNBCs. To identify novel molecular targets for ER negative breast cancer, particularly the more aggressive TNBC, we conducted a human kinome screen and identified death-associated protein kinase 1 (DAPK1) as one of the kinases that are highly expressed in ER negative breast cancer. Deletion or inhibition of DAPK1 suppresses growth of p53-mutant but not p53-wildtype breast cancer cells. Here we investigate whether DAPK1 inhibition will enhance chemotherapy action against p53-mutant TNBCs.

Experimental design and methods: We performed experiments to test cell growth of p53-mutant TNBCs that were treated with DAPK1 siRNA or DAPK1 inhibitors in combination with different doses of chemotherapy drugs including 5-FU (5-Fluorouracil), doxorubicin, cisplatin, PARP inhibitor (BMN673), paclitaxel, gemcitabine and vinorelbine.

Results: Our results show that DAPK1 inhibitors enhance the growth inhibitory effects of cisplatin and PARP inhibitor in p53-mutant TNBCs. Furthermore, combined DAPK1 inhibition (via siRNA knockdown) with cisplatin synergistically inhibits cell growth of p53-mutant TNBCs.

Conclusion: DAPK1 is a novel, promising target for the treatment of triple-negative p53-mutant breast cancer. Our studies demonstrate that DAPK1 inhibition sensitizes TNBCs to the cytotoxic effects of cisplatin or the PARP inhibitor. We are now conducting studies to determine whether DAPK1 inhibition will sensitize TNBC tumors and patient-derived TNBC xenografts to the effects of cisplatin and PARP inhibition. These studies suggest that the combination of DAPK1 inhibition with drugs that interfere with DNA repair will be useful for the treatment of the most aggressive form of breast cancer, triple-negative breast cancer.

Funding: This study was funded by a Susan G. Komen Promise grant (SAB12-00006 to P.H. Brown), a MD Anderson Knowledge Gap Moonshot grant (to P.H. Brown) and a Breast Cancer Research Foundation grant (BCRF 15101807, 2015–2016 to P.H. Brown).

Citation Format: Zhao D, Zhao J, Mazumadar A, Bollu L, Shepherd J, Ma Y, Zhang Y, Hill JL, Savage MI, Brown PH. Inhibition of death-associated protein kinase 1 enhances chemotherapy action against triple-negative breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-07-07.

Abstract P4-14-22: A single-center, open-label phase 1b study of entinostat, and lapatinib alone, and in combination with and trastuzumab in patients with HER2+ metastatic breast cancer after progression on trastuzumab

Background: Our in vitro and in vivo preclinical data showed that entinostat enhances the efficacy of lapatinib in HER2 positive (HER2+) breast cancer cells via FOXO3-mediated Bim1 expression, which resulted in enhanced apoptosis in HER2 targeted therapy (lapatinib and trastuzumab)-resistant breast cancer (IBC and non-IBC) cells [Lee et al.]. Based on these findings, we conducted a phase 1b trial of entinostat to determine the maximal tolerated dose (MTD) in combination with lapatinib alone and in combination with lapatinib and trastuzumab for metastatic HER2+ breast cancer patients (pts), who progressed on trastuzumab.

Method: This was a single-center, open-label phase 1b study to evaluate the dose limiting toxicity (DLT) and determine MTD. 3+3 dose escalation schedule was used for Cohorts 1 and 2. Pts received lapatinib and entinostat (Cohort 1) or entinostat, lapatinib, and trastuzumab (Cohort 2). Initial dose of lapatinib 1250mg in Cohort 1 and 1000mg for Cohort 2 to match standard dose in combination with trastuzumab dose. In Cohort 1, entinostat was given PO on day 1 and 15 every 28 days cycle at dose levels 10 mg (level 0), 12 mg (level 1), or 15 mg (level 2). The dose levels for Cohort 2 were 12 mg (co-level 0) or 15 mg (co-level 1) on day 1 and 15 every 28 days cycle. While lapatinib and entinostat were given 28 days cycle due to entinostat dosing, the dosing of trastuzumab followed approved schedule every 21 days starting at 8mg/kg loading followed by 6mg/kg q 3 wks in Cohort 2 and 3. After the MTD of entinostat in cohort 2 was determined at 12mg, an expansion cohort of 10 pts (cohort 3) was conducted.

Results: Median age was 52 (26-69 yrs). Median number of prior trastuzumab-based regimens was 2 (1-6), 8 pts had lapatinib containing treatment prior to the trial, including 5 pts who had clinical benefit. 16 had ER+ and 13 ER negative, and 9 had IBC. Clinical efficacy and toxicity of treatment is summarized in table 1. Out of 14 pts who had clinical benefit (CR, PR, SD), 6 had IBC. Three pts are still on therapy (1CR, 1PR, 1SD).

Table 1. Clinical Efficacy, Toxicity of combination Receptor StatusResponseGrade 3 toxicityGrade 4 toxicityCohort 1HER2+/ER- (N=8) HER2+/ER+ (N=7)CR (N=1; 8M), SD (N=4;1,2,4M)Lapatinib dose reduction: 3 pts Rash (2) Abdominal pain + dyspnea (1)Entinostat dose reduction: 2pts Neutropenia (1 at 12mg, 1 at 15mg)Cohort 2/3HER2+/ER- (N=8) HER2+/ER+ (N=6)CR (N=2; 3,6M), PR (N=2;4,5M) SD (N=5;1,2,4,6M)Lapatinib dose reduction: 2 pts Diarrhea (N=1 at 12mg N=1 at 10mg) Entinostat dose reduction: 5 pts Neutropenia (N=2 at 12 mg) Leukopenia (N=1 at 12mg) Anemia (N=1 at 12mg)Entinostat dose reduction: 2pts Hypokalemia (N=1 at 12mg) Thrombocytopenia (N=1 at 15mg)CR: complete response, PR: partial response, SD: stable disease, N=number of pts, M=months

Conclusion: MTD was reached at 12mg q 2wkly entinostat, lapatinib 1000 mg daily and trastuzumab 8 mg/kg followed by 6mg/kg q 3 wks. This combination was safe and had promising clinical efficacy in patients with trastuzumab-resistant metastatic HER2+ breast cancer including IBC, warranting further study.

Citation Format: Lim B, Jackson S, Alvarez RH, Ibrahim NK, Willey JS, Murthy RK, Booser DJ, Giordano SH, Barcenas CH, Brewster A, Walters RS, Brown PH, Tripathy D, Valero V, Ueno NT. A single-center, open-label phase 1b study of entinostat, and lapatinib alone, and in combination with and trastuzumab in patients with HER2+ metastatic breast cancer after progression on trastuzumab. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-14-22.

Long-term effects of inhaled budesonide on screening-detected lung nodules

BACKGROUND

A previously carried out randomized phase IIb, placebo-controlled trial of 1 year of inhaled budesonide, which was nested in a lung cancer screening study, showed that non-solid and partially solid lung nodules detected by low-dose computed tomography (LDCT), and not immediately suspicious for lung cancer, tended to regress. Because some of these nodules may be slow-growing adenocarcinoma precursors, we evaluated long-term outcomes (after stopping the 1-year intervention) by annual LDCT.

PATIENTS AND METHODS

We analyzed the evolution of target and non-target trial nodules detected by LDCT in the budesonide and placebo arms up to 5 years after randomization. The numbers and characteristics of lung cancers diagnosed during follow-up were also analyzed.

RESULTS

The mean maximum diameter of non-solid nodules reduced significantly (from 5.03 mm at baseline to 2.61 mm after 5 years) in the budesonide arm; there was no significant size change in the placebo arm. The mean diameter of partially solid lesions also decreased significantly, but only by 0.69 mm. The size of solid nodules did not change. Neither the number of new lesions nor the number of lung cancers differed in the two arms.

CONCLUSIONS

Inhaled budesonide given for 1 year significantly decreased the size of non-solid nodules detected by screening LDCT after 5 years. This is of potential importance since some of these nodules may progress slowly to adenocarcinoma. However, further studies are required to assess clinical implications.

CLINICAL TRIAL NUMBER

NCT01540552.

Estimates of benefits and harms of prophylactic use of aspirin in the general population

BACKGROUND

Accumulating evidence supports an effect of aspirin in reducing overall cancer incidence and mortality in the general population. We reviewed current data and assessed the benefits and harms of prophylactic use of aspirin in the general population.

METHODS

The effect of aspirin for site-specific cancer incidence and mortality, cardiovascular events was collated from the most recent systematic reviews. Studies identified through systematic Medline search provided data regarding harmful effects of aspirin and baseline rates of harms like gastrointestinal bleeding and peptic ulcer.

RESULTS

The effects of aspirin on cancer are not apparent until at least 3 years after the start of use, and some benefits are sustained for several years after cessation in long-term users. No differences between low and standard doses of aspirin are observed, but there were no direct comparisons. Higher doses do not appear to confer additional benefit but increase toxicities. Excess bleeding is the most important harm associated with aspirin use, and its risk and fatality rate increases with age. For average-risk individuals aged 50-65 years taking aspirin for 10 years, there would be a relative reduction of between 7% (women) and 9% (men) in the number of cancer, myocardial infarction or stroke events over a 15-year period and an overall 4% relative reduction in all deaths over a 20-year period.

CONCLUSIONS

Prophylactic aspirin use for a minimum of 5 years at doses between 75 and 325 mg/day appears to have favourable benefit-harm profile; longer use is likely to have greater benefits. Further research is needed to determine the optimum dose and duration of use, to identify individuals at increased risk of bleeding, and to test effectiveness of Helicobacter pylori screening-eradication before starting aspirin prophylaxis.

Abstract OT3-3-01: A multicenter phase II study of docosahexaenoic acid (DHA) in triple negative breast cancer (TNBC) survivors

Background: The development of effective chemopreventive strategies to reduce the risk of TNBC, is a critical unmet need. Obesity is associated with a chronic inflammatory condition in the white adipose tissue of the breast, characterized microscopically by crown-like structures of the breast (CLS-B). The presence and extent of these lesions is associated with a series of proinflammatory mediators, including tumor necrosis factor-α (TNF-α), cyclooxygenase-2 (COX-2), interleukin-1β (IL-1β) and aromatase. Importantly these proinflammatory mediators are known to be involved in breast carcinogenesis. In translational studies to date, the strongest correlations have been seen between CLS-B and TNF-α. Therefore, we aim to evaluate whether treatment with a dietary supplement, DHA, an omega-3 fatty acid, with potent effects on TNF-α, can decrease obesity-related breast inflammation in women.

Trial design: This is a randomized phase II placebo-controlled, double-blinded study of DHA in overweight/obese patients (pts), defined as body mass index (BMI) ≥25 with a history of TNBC. Pts will receive DHA or placebo twice daily for 24 weeks and will undergo core biopsies from normal (non-irradiated contralateral) breast tissue before and after the treatment to determine whether DHA can decrease obesity-related breast inflammation.

Eligibility: Inclusion criteria: 1) Age ≥ 18. 2) BMI ≥ 25. 3) Completed treatment for stage I-III TNBC ≥ 6 months prior. 4) No clinical evidence of disease. 5) Adequate accessible breast tissue for pre- and post- treatment biopsy, consisting of one breast unaffected by invasive cancer, which has not been radiated or surgically augmented. 6) Adequate organ and bone marrow function. 7) ECOG status ≤2. Exclusion criteria: 1) DHA supplementation. 2) Aspirin/NSAID use in the month preceding and during the trial. 3) Therapeutic anticoagulation. 4) Regular use of statins, steroids, or immunomodulators.

Specific aims: The primary objective is to determine whether treatment with DHA for 24 weeks at 1,000 mg twice daily as compared to placebo reduces normal breast tissue levels of TNF-α in overweight/obese pts with a history of TNBC. The secondary objective is to evaluate the effect of DHA on the change from baseline in levels of the following tissue biomarkers: COX-2, IL-1β, aromatase, and CLS-B. Exploratory endpoints include assessment of age as a predictor of CLS-B and inflammatory biomarkers and the evaluation of red blood cell fatty acid levels as a surrogate of DHA compliance.

Statistical methods: Percent change in TNF-α mRNA levels in normal breast tissue between DHA and placebo arm will be compared using two-sample t-test. If normality assumptions are violated, a two-sample Wilcoxon rank-sum test will be used. With 30 subjects in each arm, we will have 80% power to detect effect size as small as 0.74 at 0.05 significance level using a two-sided, two-sample, Student t-test.

Accrual: A total of 60 evaluable pts will be enrolled. Assuming a 10% dropout rate and 10% non-evaluable rate, up to 76 participants will be randomized in this study. This trial is currently enrolling pts.

Contact information: For more information on this trial, please visit clinicaltrials.gov (NCT01849250) or contact Ayca Gucalp MD (gucalpa@mskcc.org).

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr OT3-3-01.

Abstract P4-06-01: Expression and DNA copy number profiling suggest novel therapeutic approaches for triple negative breast cancer subtypes

The aggressive triple negative breast cancers (TNBCs), which lack ER, PR and HER2, comprise a high-risk subset of human breast cancers which remain poorly characterized and lack effective treatments. While recent meta-analyses indicate the complexity of these tumors, no robust independently validated phenotypes have been defined. We have identified four distinct molecular subtypes through independent non-negative matrix factorization of expression data from 84 Discovery and 114 Validation Set TNBCs profiled at a single institution, with matching CNV data (SNP array). We then classified 485 publically available TNBCs via a centroid signature of only 80 genes. All three sets supported stratification of tumors by cell cycle, DNA repair, and immunological signaling pathways that have significantly different clinical outcomes. The first subtype, composed of intermediate grade tumors, resembles the “Molecular Apocrine” or “Luminal AR” subtype described previously and was defined by enrichment of prolactin, aryl hydrocarbon receptor, and ERBB4 signaling with activated downstream expression patterns of ESR1 signaling. Large deletions of chromosome 6 were specific to this subtype. While focal deletions at 14q21.2 and 12q13.13 were present in >60% of tumors of the other subtypes, the genes at these loci (FOXA1 and ERBB3) were overexpressed in the first subtype. Inhibitors of AR and MUC1, both overexpressed, may prove effective for these tumors. A second subtype defined as “Claudin-Low” or “Mesenchymal Stem-Like” showed overexpression of markers of mesenchymal lineage (ADIPOQ and OGN). Targets responsive to beta-blockers (ADRB2), and targetable molecules associated with platelet and endothelial function (EDNRB, PLA2G2A, PTGER3/4, PTGFR, PTGFRA) were also upregulated. Two basal-like subtypes were found with significant differences in DFS and OS, even after correction for available clinical covariates. The high-risk (31% 5-year DFS), low immune function subtype was regulated by SOX 10, 8, and 6 and had unique copy-number driven expression of FGFR2. The second, low-risk (78% 5-year DFS) basal-like subtype was enriched for overexpression of many immune pathways, regulated by increased STAT1 and activated STAT downstream signaling, as well as exclusive upregulation of CTLA4. This subtype also had the lowest tumor cell fraction as calculated by allele specific copy number analysis of tumors (ASCAT). Both basal-like subtypes expressed TTK, CHEK1, TOP2A, and AURKA. CDK1 was correlated with copy number variation at 10q21.1. We proposed and validated four molecular subtypes of TNBC before applying the resulting gene signature to 7 external expression sets. The described subtypes vary by clinical behavior and inferred biology. Each subtype appears to have specific gene expression regulated by copy number variation and a set of genes targetable by currently available agents. These findings further define the heterogeneity of TNBCs and suggest potential therapeutic targets for each subtype.

This work was supported by a Promise grant from the Susan G. Komen for the Cure Foundation (KG081694).

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-06-01.

Abstract OT3-3-02: Phase IIB randomized double-blind placebo-controlled biomarker modulation study of high dose vitamin D in premenopausal women at high-risk for breast cancer: SWOG S0812

Background: Priorities in breast cancer chemoprevention include developing agents effective against estrogen receptor (ER)-negative breast cancer and validating intermediate biomarkers which correlate with breast cancer risk. Vitamin D is a fat-soluble vitamin which regulates calcium and bone homeostasis, but also has diverse biological effects relevant to breast carcinogenesis. The biologically active form of vitamin D [1,25(OH)D] interacts with the vitamin D receptor (VDR) to modulate cell proliferation, differentiation, apoptosis, and angiogenesis. Epidemiologic data suggests that serum 25(OH)D levels >40-50 ng/ml are associated with a 40-50% reduction in breast cancer risk compared to women with vitamin D deficiency (<20 ng/ml). Given the high prevalence of vitamin D deficiency in the general population, vitamin D3 3000-4000 IU daily would be required to raise 25(OH)D to this putative target level. The central hypothesis of this proposal is that high-dose vitamin D will modulate biomarkers of breast cancer risk.

Trial Design: This trial is a phase IIB, randomized, double-blind, placebo-controlled study of oral vitamin D3 (cholecalciferol) 20,000 IU (2 capsules) weekly for one year in 200 premenopausal women at high-risk for breast cancer. Both groups will be supplemented with a standard dose of vitamin D3 600 IU daily. Participants will undergo a mammogram and optional random core breast biopsy timed within 10 days after the start of their menstrual cycle at baseline and 1 year and blood collections at baseline, 6, and 12 months. Participants will be monitored for toxicity, particularly hypercalcemia and hypercalciuria, every 3 months during the 1-year intervention.

Main Eligibility Criteria: High-risk is defined as a 5-year Gail risk score ≥1.67% or lifetime risk ≥20%, history of atypical hyperplasia, lobular or ductal carcinoma in situ, germline mutations in BRCA1, BRCA2, p53, or PTEN, history of stage I-II breast cancer in remission for >5 years, or baseline mammographic density >50%. Other eligibility criteria include baseline serum 25(OH)D ≤32 ng/ml, normal serum calcium and urine calcium/creatinine ratio, and no history of kidney stones.

Specific Aims: The primary endpoint is change in mammographic density at 12 months compared to baseline between the vitamin D and placebo groups. Secondary exploratory endpoints include breast tissue-based biomarkers (Ki-67, cleaved caspase-3, ER, VDR, and 1α-hydroxylase) and blood-based biomarkers (25(OH)D, 1,25(OH)D, PTH, IGF-1, IGFBP-3, VDR polymorphisms).

Statistical Methods: Power calculations are based on a two-sample comparison of normal deviates, using a 2-sided, 0.05-level test. To be conservative, we assume that 15% will have missing breast density data at 12 months and a 2% difference in mammographic density between intervention and control at 12 months with a the standard deviation for each arm of 4%. With 200 women randomized, the study will have 90% power to detect this difference.

Target Accrual: 200. Sixty-seven patients accrued as of June 2013. Accrual completion expected December 2014.

Contact: Katherine Crew, Columbia University Medical Center, kd59@columbia.edu.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr OT3-3-02.

A SNP in steroid receptor coactivator-1 disrupts a GSK3β phosphorylation site and is associated with altered tamoxifen response in bone

The coregulator steroid receptor coactivator (SRC)-1 increases transcriptional activity of the estrogen receptor (ER) in a number of tissues including bone. Mice deficient in SRC-1 are osteopenic and display skeletal resistance to estrogen treatment. SRC-1 is also known to modulate effects of selective ER modulators like tamoxifen. We hypothesized that single nucleotide polymorphisms (SNP) in SRC-1 may impact estrogen and/or tamoxifen action. Because the only nonsynonymous SNP in SRC-1 (rs1804645; P1272S) is located in an activation domain, it was examined for effects on estrogen and tamoxifen action. SRC-1 P1272S showed a decreased ability to coactivate ER compared with wild-type SRC-1 in multiple cell lines. Paradoxically, SRC-1 P1272S had an increased protein half-life. The Pro to Ser change disrupts a putative glycogen synthase 3 (GSK3)β phosphorylation site that was confirmed by in vitro kinase assays. Finally, knockdown of GSK3β increased SRC-1 protein levels, mimicking the loss of phosphorylation at P1272S. These findings are similar to the GSK3β-mediated phospho-ubiquitin clock previously described for the related coregulator SRC-3. To assess the potential clinical significance of this SNP, we examined whether there was an association between SRC-1 P1272S and selective ER modulators response in bone. SRC-1 P1272S was associated with a decrease in hip and lumbar bone mineral density in women receiving tamoxifen treatment, supporting our in vitro findings for decreased ER coactivation. In summary, we have identified a functional genetic variant of SRC-1 with decreased activity, resulting, at least in part, from the loss of a GSK3β phosphorylation site, which was also associated with decreased bone mineral density in tamoxifen-treated women.

P3-14-09: A Phase II Preoperative Study of Dasatinib, a Multi-Targeted Tyrosine Kinase Inhibitor, in Locally Advanced “Triple-Negative” Breast Cancer Patients

Background: We previously reported that kinases (Src, Yes-1, cKIT, Abl, and EPH4) were druggable in triple negative breast cancer (TNBC). In this clinical trial, we sought to translate these findings by treating TNBC patients with dasatinib, a multi-targeted kinase inhibitor against these targets.

Methods: Women with stage II-III TNBC were eligible. Patients received dasatinib at 100 mg daily for 3 to 4 weeks before standard-of-care definitive surgery and chemotherapy. Biopsies were performed at baseline, week 1, and at the time of surgery. A cohort of patients had positron emission mammography (PEM; baseline and at 2–3 weeks of dasatinib therapy). This study was designed to detect an increase in clinical response rate from 10% to 25%, using a Simon optimal two stage design, with one-sided alpha=5% and power=80%. At least 3 responses out of 22 patients were needed to proceed to the second stage.

Results: 22 patients were enrolled (Table 1). Median tumor size was 7.0 cm (range 2.4-25 cm). Adverse events were modest, mainly grade 1–2 (headache: 45%, abnormal LFTs: 55%, GI: 23%, fatigue: 18%). One patient had a myocardial infarction 24 hours after starting dasatinib. Out of 22 patients, 2 (9%) had a clinical partial response after 3–4 weeks of therapy, 15 had stable disease (68%), while 5 had progressive disease (23%). Of the 8 patients who received paired PEM imaging, metabolic responses were observed in 2 patients (25%). Conclusion: A short course of dasatinib led to clinical responses in 2 out of 22 patients with TNBC, and the study did not proceed to second stage. Since TNBC is a heterogeneous disease, biomarker studies including sequencing of candidate genes like B-RAF for inactivating mutations might enable selection of those TNBC patients who could benefit from dasatinib.

PD03-03: Identification of Transcription Factors Critical for the Growth of Basal Breast Cancer

Background: Basal breast cancers are aggressive, poor prognosis tumors that occur commonly in young women and in African American women. Profiling of breast tumor mRNA has demonstrated that there are differences in gene expression between the basal and luminal subtypes of breast cancer. In this study, we identified response elements in the genes that define basal breast cancers, and identified transcription factors that are critical for the growth of basal breast cancer cells.

Materials and Methods: We performed promoter analysis using 4 published microarray studies (PMID: 12829800; PMID: 19435916; PMID: 17157792; PMID: 11562467) to select genes that are highly expressed in basal tumors compared to luminal tumors. For this analysis we selected 61 genes highly expressed in a set of basal tumors in any of the 4 microarray studies. We next used the online tool, CORE_TF, along with the MATCH algorithm minimizing for the sum of false positives and false negatives to identify binding motifs within the promoter (defined from −1 kb to the first exon) of each gene. The frequency of binding motif occurrence for these 61 basal genes was compared to the frequency within the promoters of 3000 randomly selected genes. Significance was tested using an exact binomial test with a cutoff of p<0.05. RNA expression of motif-identified transcription factors was then analyzed in-silico using all 10 datasets in Oncomine™ that contained annotation for triple-negative status. Expression in triple negative samples was compared to expression in non-triple-negative samples with a cutoff of p <0.05. We next performed siRNA knockdown studies to determine whether the identified TFs regulate basal breast cancer growth. Basal and luminal cells transfected with control and specific siRNAs were grown in triplicate and mean cell counts at day 6 were compared.

Results: Promoter analysis identified 24 binding motifs that were over-represented in basal breast tumor genes compared to a random set of 3000 genes. TransFac analysis indicated that 47 transcription factors bind the 24 identified motifs. Oncomine analysis showed that 8 of the 47 transcription factors were significantly more highly expressed in basal as compared to non-basal tumors. Identified transcription factors include FOXC1, FOXM1, CDC5L, E2F3, CEBP and NF-Y. siRNA to FOXM1 in 2 basal breast cell lines reduced growth by >70% after 6 days, whereas, in the luminal cell line MCF7, growth was reduced by 15%.

Discussion: This study identified transcription factors that are highly expressed in basal breast tumors (as compared to non-basal breast tumors). siRNA knockdown studies showed that FOXM1 is critical for basal breast cancer cell growth. These results suggest that transcription factors highly expressed in basal breast cancers may be novel targets for the treatment of this disease.

These studies were supported by a Promise grant from the Susan G. Komen for the Cure (PB, SGH), and by the Norman E. Brinker Award for Research Excellence (PB).

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr PD03-03.

P4-01-18: AP-1 Blockade Potentiates the Anti-Tumor Effect of Endocrine Treatment and Reverts the Resistant Phenotype in Hormone Receptor-Positive Breast Cancer

Background: Resistance to endocrine therapy is a major clinical issue. The transcription factor AP-1 is a key regulator of cell growth and survival as well as a downstream signaling component of several pathways deregulated in endocrine-resistant breast cancer. We have previously shown that acquired endocrine resistance is associated with increased AP-1 activity. AP-1 has also been shown to interact with and modulate the ER network and transcriptional program, especially under hyperactive growth factor signaling, which is commonly associated with endocrine resistance. We hypothesized that interfering with AP-1 function would circumvent endocrine resistance possibly due to its role in modulating ER transcriptional activity.

Methods and results: We inhibited AP-1 function by a genetic approach. We used two different MCF7 clones stably transfected with a Doxycycline (Dox)-inducible dominant-negative (DN) c-Jun (MCF7/Tet-Off Tam67 clones 62 and 67) and two vector-alone control MCF7 clones. Xenografts of these clones were established in ovariectomized nude mice supplemented with estrogen (E2). Mice were then randomized to continued E2 supplementation (control) or to endocrine therapy with either estrogen deprivation (ED) or tamoxifen (Tam), all in the presence or absence of Dox to induce the DN c-Jun expression. AP-1 blockade in both MCF7/Tet-Off Tam67 clones significantly enhanced sensitivity to Tam by reducing time to tumor size halving (p=.014 and p=.006 for clone 62 and 67, respectively) and time to complete tumor disappearance (p=.001 and p=.0034 for clone 62 and 67, respectively). Similar results were obtained with ED treatment. In addition, AP-1 blockade significantly delayed the onset of Tam resistance by increasing time to tumor size doubling (p=.0028). Furthermore, induction of DN c-Jun resulted in a dramatic shrinkage of growing tumors after long-term Tam treatment, suggesting reversal of endocrine resistance with AP-1 blockade. None of the above effects was observed in control clones upon Dox removal. Interestingly, no significant effect of AP-1 blockade was observed on E2-stimulated tumor growth. IHC analysis showed that AP-1 blockade induced tumor response by reducing proliferation (i.e., decreased % of Ki67- and phospho-Histone 3-positive cells) and by inducing apoptosis (i.e., increased % of cleaved caspase 3/7-positive cells). Bioinformatic analyses were conducted to intersect our MCF7 xenograft/Tam-resistant gene signature and the datasets of genes associated with ER DNA-binding sites obtained by whole-genome ER cistromic analysis under estrogen or epidermal growth factor (EGF) stimulation of MCF7 cells. A significant enrichment of the genes associated with the EGF-unique ER DNA-binding sites was observed within our Tam-resistant signature (p<2E-16). Remarkably, 90% of these DNA binding sites harbored an AP-1 motif.

Conclusions: We show that AP-1 blockade increases tumor sensitivity and circumvents resistance to endocrine therapy, thus warranting the development of AP-1-targeted therapy to improve endocrine treatment outcomes. Overall, we suggest that AP-1 is critical in induction of a switch in the ER transcriptional program and may be a new hallmark of endocrine resistance.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-01-18.

Plant nutrition for sustainable development and global health

BACKGROUND

Plants require at least 14 mineral elements for their nutrition. These include the macronutrients nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg) and sulphur (S) and the micronutrients chlorine (Cl), boron (B), iron (Fe), manganese (Mn), copper (Cu), zinc (Zn), nickel (Ni) and molybdenum (Mo). These are generally obtained from the soil. Crop production is often limited by low phytoavailability of essential mineral elements and/or the presence of excessive concentrations of potentially toxic mineral elements, such as sodium (Na), Cl, B, Fe, Mn and aluminium (Al), in the soil solution.

SCOPE

This article provides the context for a Special Issue of the Annals of Botany on 'Plant Nutrition for Sustainable Development and Global Health'. It provides an introduction to plant mineral nutrition and explains how mineral elements are taken up by roots and distributed within plants. It introduces the concept of the ionome (the elemental composition of a subcellular structure, cell, tissue or organism), and observes that the activities of key transport proteins determine species-specific, tissue and cellular ionomes. It then describes how current research is addressing the problems of mineral toxicities in agricultural soils to provide food security and the optimization of fertilizer applications for economic and environmental sustainability. It concludes with a perspective on how agriculture can produce edible crops that contribute sufficient mineral elements for adequate animal and human nutrition.

The relationship of the female reproductive success of Eucalyptus globulus to the endogenous properties of the flower

Low capsule and seed set is a major factor limiting seed production in Eucalyptus globulus seed orchards. Controlled pollination studies showed that the reproductive success (number of seeds produced per flower pollinated) was primarily determined by the female. We aimed to identify the factors contributing to the differences in reproductive success between female genotypes in terms of the physical and anatomical properties of the flower. We studied pairs of genotypes of high and low reproductive success from each of three races (Furneaux Group, Strzelecki Ranges and Western Otways) growing in a seed orchard. Controlled pollinations were performed on six females and along with flower physical measurements, pollen tube growth and seed set were assessed. Overall tree reproductive success was positively correlated with flower size, ovule numbers, style size, cross-sectional area of conductive tissue within the style (all of which were inter-correlated) and the proportion of pollen tubes reaching the bottom of the style. Significant positive correlations of reproductive success and flower physical properties between different ramets of the same genotypes across seasons suggests a genetic basis to the variation observed. The majority of pollen tube attrition occurred within the first millimetre of the cut style and appeared to be associated with differences in style physiology. When examined as pairs within races the difference in reproductive success for the Western Otways pair was simply explained by differences in flower size and the number of ovules per flower. Physical features did not differ significantly for the Strzelecki Ranges pair, but the proportion of pollen tubes reaching the bottom of the style was lower in the less reproductively successful genotype, suggesting an endogenous physiological constraint to pollen tube growth. The difference in reproductive success between the females from the Furneaux Group was associated with a combination of these factors.

The rexinoid, bexarotene, prevents the development of premalignant lesions in MMTV-erbB2 mice

Retinoids, vitamin A analogues that bind to retinoic acid receptor (RAR) or retinoid X receptor (RXR), play important roles in regulating cell proliferation, apoptosis, and differentiation. Recently, RXR-selective ligands, also referred to as rexinoids, have been investigated as potential chemopreventive agents for breast cancer. Our previous studies demonstrated that the rexinoid bexarotene significantly prevented ER-negative mammary tumourigenesis with less toxicity than naturally occurring retinoids in animal models. To determine whether bexarotene prevents cancer at the early stages during the multistage process of mammary carcinogenesis, we treated MMTV-erbB2 mice with bexarotene for 2 or 4 months. The development of preinvasive mammary lesions such as hyperplasias and carcinoma-in-situ was significantly inhibited. This inhibition was associated with reduced proliferation, but no induction of apoptosis. We also examined the regulation of a number of rexinoid-modulated genes including critical growth and cell cycle regulating genes using breast cell lines and mammary gland samples from mice treated with rexinoids. We showed that two of these genes (DHRS3 and DEC2) were modulated by bexarotene both in vitro and in vivo. Identification of these rexinoid-modulated genes will help us understand the mechanism by which rexinoid prevents cancer. Such rexinoid-regulated genes also represent potential biomarkers to assess the response of rexinoid treatment in clinical trials.

The AP-1 transcription factor regulates breast cancer cell growth via cyclins and E2F factors

The activating protein-1 (AP-1) transcription factor transduces growth signals through signal transduction pathways to the nucleus, leading to the expression of genes involved in growth and malignant transformation in many cell types. We have previously shown that overexpression of a dominant negative form of the cJun proto-oncogene, a cJun dominant negative mutant (Tam67), blocks AP-1 transcriptional activity, induces a G(1) cell cycle block and inhibits breast cancer cell growth in vitro and in vivo. We found that AP-1 blockade by Tam67 in MCF-7 breast cancer cells downregulates cyclin D1 transcriptional activity by at least two mechanisms: by suppressing transcription at the known AP-1 binding site (-934/-928) and by suppressing growth factor-induced expression through suppressing E2F activation at the E2F-responsive site (-726/-719). AP-1 blockade also led to reduced expression of E2F1 and E2F2, but not E2F4, at the mRNA and protein levels. Chromatin immunoprecipitation and supershift assays demonstrated that AP-1 blockade caused decreased binding of E2F1 protein to the E2F site in the cyclin D1 promoter. We also found that Tam67 suppressed the expression of the E2F1 dimerizing partner, DP1 and E2F-upregulated cell cycle genes (cyclins E, A, B and D3) and enhanced the expression of E2F-downregulated cell cycle genes (cyclins G(2) and I). Reduced expression of other E2F-regulated genes was also seen with AP-1 blockade and E2F suppression. Thus, the AP-1 factor regulates the expression of cyclin D and E2F (the latter in turn regulates E2F-downstream genes), leading to cell cycle progression and breast cancer cell proliferation.

Horse rug lung: toxic pneumonitis due to fluorocarbon inhalation

Fluorocarbons are widely used in industry, and manifestations of inhalation toxicity include polymer fume fever, reactive airways dysfunction, and bronchospasm. Only seven cases of alveolitis occurring acutely after inhalation have been reported. This paper presents four cases of toxic pneumonitis due to direct inhalation of industrial fluorocarbon used as a waterproofing spray for horse rugs. These cases differ from previous reports and show that chronic as well as acute alveolitis can result from fluorocarbon inhalation. Corticosteroid treatment may be beneficial. The need for stricter control in the workplace is emphasised.

Pollination biology of oilseed poppy, Papaver somniferum L

Although poppies (Papaver somniferum L.) are one of the oldest cultivated plants relatively little is known of their pollination biology. We have investigated the relative importance of wind and insects in the pollination of poppies and identified potential insect pollinators. Wind pollination was found to be negligible, insect pollination was responsible for the majority of out-crossing, and self-pollination was the dominant mode of poppy fertilisation. Honeybees and flies were identified as the main potential cross-pollinators of Tasmanian poppies. Using a transgenic poppy field trial in which approximately 50% of the pollen grains produced were transgenic, we have determined the level of pollen-mediated gene flow by scoring over 50 000 seeds for the presence of a selectable marker gene. Gene flow was measured using a 10-m buffer area that surrounded the field trial. It was highest at 0.1 m with 3.26% of seeds found to be transgenic and declined over distance with 1.73% transgenic seeds at 0.5 m, 1.80% at 1 m, 0.86% at 2 m, 0.34% at 5 m, 0.12% at 9 m, and 0.18% at 10 m. These results demonstrate that under Tasmanian conditions, pollen-mediated gene flow occurs at modest levels in poppies that are in close proximity to each other and is most probably mediated by honeybees and flies.

Lung cancer: the importance of seeing a respiratory physician

Patients with lung cancer present to and are managed by a variety of clinicians. In this study the effect of involvement by a respiratory physician on the diagnosis, staging, treatment and survival of a large unselected group of lung cancer patients was investigated. The study population was derived from the Scottish Cancer Registry. A total of 3,855 patients diagnosed during 1995 with lung cancer were studied. The data were validated and supplemented by references to medical records. The study found that a respiratory physician had been involved in the initial management of 2,901 (75.3%) patients. These patients were found more likely to have had the cancer diagnosis confirmed by histological methods and to have received active treatment with surgery, radiotherapy or chemotherapy. Survival, 1 yr after diagnosis was higher in patients who saw a respiratory physician (24.4 versus 11.1%) and benefit was found to have remained 3 yrs after diagnosis (8.1 versus 3.7%). Although the patients who had not seen a respiratory physician were generally older, and had more extensive disease, after correcting for age, stage and other prognostic factors, the relative hazard ratio of death for those not managed by a respiratory physician was 1.44. The data from this study supports the recommendations of recent lung cancer guidelines for the early involvement by a respiratory physician.

Pre-clinical applications of transgenic mouse mammary cancer models

Breast cancer is a leading cause of cancer morbidity and mortality. Given that the majority of human breast cancers appear to be due to non-genetic factors, identifying agents and mechanisms of prevention is key to lowering the incidence of cancer. Genetically engineered mouse models of mammary cancer have been important in elucidating molecular pathways and signaling events associated with the initiation, promotion, and the progression of cancer. Since several transgenic mammary models of human breast cancer progress through well-defined cancer stages, they are useful pre-clinical systems to test the efficacy of chemopreventive and chemotherapeutic agents. This review outlines several oncogenic pathways through which mammary cancer can be induced in transgenic models and describes several types of preventive and therapeutic agents that have been tested in transgenic models of mammary cancer. The effectiveness of farnesyl inhibitors, aromatase inhibitors, differentiating agents, polyamine inhibitors, anti-angiogenic inhibitors, and immunotherapeutic compounds including vaccines have been evaluated in reducing mammary cancer and tumor progression in transgenic models.

Lymphangioleiomyomatosis. A series of three case reports illustrating the link with high oestrogen states

Lymphangioleiornyomatosis is a rare lung disorder characterised by cystic air spaces and smooth muscle proliferation. The condition, which most commonly presents with dyspnoea, pneumothoraces or cough, is only described in females and is most commonly diagnosed during childbearing years. Three cases are presented which illustrate typical features of the disease and the association with high oestrogen levels. The first had recurrent pneumothoraces during her first pregnancy. The second lady was post menopausal at diagnosis but her symptoms predated her menopause. The third, presented with dyspnoea, abnormal chest sensations and a pneumothorax. She had a history of hyperprolactinaemia with secondary amenorhoea due to low oestrogen levels which had been corrected prior to her presentation. All three patients had reduced gas transfer and abnormalities in spirometry, two had reticular shadowing on their chest radiograph and all had typical appearances on lung computerised tomography. Although disease progression was variable, all patients showed a gradual decline in lung function.

Permeability and the mechanism of transport of boric acid across the plasma membrane of Xenopus laevis oocytes

Boron is an essential element for vascular plants and for diatoms, cyanobacteria, and a number of species of marine algal flagellates. Boron was recently established as an essential micronutrient for frogs (Xenopus laevis) and preliminary evidence suggests that it may be essential for all animals. The main form of B, which is available in the natural environment, is in the form of undissociated boric acid. The permeability coefficient and the mechanism of transport of boric acid, however, have not been experimentally determined across any animal membrane or cell. In the experiments described here, the permeability coefficient of boric acid in Xenopus oocytes was 1.5 x 10(-6) cm/s, which is very close with the permeability across liposomes made with phosphatidylcholine and cholesterol (the major lipids in the oocyte membrane). Moreover, we investigated the mechanism of boric acid movement across the membrane of Xenopus oocytes and we compared it with the transport across artificial liposomes. The transport of boric acid across Xenopus oocytes was not affected by inhibitors such as HgCl2, phloretin, or 4,4-diisothiocyanatostilbene-2,2'-D-sulfonic acid (DIDS). The kinetics of B uptake was linear with concentration changes, and the permeability remained the same at different external boric acid concentrations. These results suggest that B transport occurs via simple passive diffusion through the lipid bilayer in Xenopus oocytes.

AP-1 blockade inhibits the growth of normal and malignant breast cells

We have previously demonstrated that basal AP-1 transcriptional activity is high in normal human mammary epithelial cells, intermediate in immortal breast cells, and relatively low in breast cancer cells. In this study we investigated whether differences in AP-1 transcriptional activity reflect differences in breast cells' dependence on AP-1 for proliferation. The cJun dominant negative, TAM-67, was used to determine the effect of AP-1 blockade on the growth of normal, immortal and malignant breast cells. We first showed that TAM-67 inhibits AP-1 activity in normal and malignant breast cells. We then determined whether this AP-1 inhibitor affected colony forming efficiency of the immortalized and malignant breast cells. The AP-1 inhibitor reduced colony formation of immortal breast cells by over 50% (by 58% in 184B5 cells and 62% in MCF10A cells), and reduced colony formation in the breast cancer cell line MCF7 by 43%, but did not reduce colony formation in the other breast cancer cell lines (T47D, MDA MB231 and MDA MB 435). We also determined the effect of AP-1 blockade on the growth of normal breast cells using a single cell proliferation assay. Using this assay, the growth of normal breast cells was extremely sensitive to AP-1 blockade, while immortal breast cells were moderately sensitive. We next directly tested the effect of TAM-67 expression on the growth of MCF7 breast cancer cells, using cells stably transfected with TAM-67 under the control of a doxycycline-inducible promoter. Upon induction, TAM-67 was expressed and AP-1 activity was inhibited in these cells. We then measured the growth of these cells in the presence or absence of TAM-67. The results of these studies show that the growth of MCF7 cells was suppressed by the AP-1 inhibitor, TAM-67. These results demonstrate that normal and immortalized breast cells, and some breast cancer cells (such as MCF7), require AP-1 to transduce proliferative signals, while other breast cancer cells (such as T47D, MDA MB 231 and MDA MB 435) do not. These studies suggest that the AP-1 transcription factor is a potential target for future agents for the prevention or treatment of breast cancer.

Forkhead homologue in rhabdomyosarcoma functions as a bifunctional nuclear receptor-interacting protein with both coactivator and corepressor functions

In a search for novel transcriptional intermediary factors for the estrogen receptor (ER), we used the ligand-binding domain and hinge region of ER as bait in a yeast two-hybrid screen of a cDNA library derived from tamoxifen-resistant MCF-7 human breast tumors from an in vivo athymic nude mouse model. Here we report the isolation and characterization of the forkhead homologue in rhabdomyosarcoma (FKHR), a recently described member of the hepatocyte nuclear factor 3/forkhead homeotic gene family, as a nuclear hormone receptor (NR) intermediary protein. FKHR interacts with both steroid and nonsteroid NRs, although the effect of ligand on this interaction varies by receptor type. The interaction of FKHR with ER is enhanced by estrogen, whereas its interaction with thyroid hormone receptor and retinoic acid receptor is ligand-independent. In addition, FKHR differentially regulates the transactivation mediated by different NRs. Transient transfection of FKHR into mammalian cells dramatically represses transcription mediated by the ER, glucocorticoid receptor, and progesterone receptor. In contrast, FKHR stimulates rather than represses retinoic acid receptor- and thyroid hormone receptor-mediated transactivation. Most intriguingly, overexpression of FKHR dramatically inhibits the proliferation of ER-dependent MCF-7 breast cancer cells. Therefore, FKHR represents a bifunctional NR intermediary protein that can act as either a coactivator or corepressor, depending on the receptor type.

Kinetic analysis of boron transport in Chara

The permeability of biological membranes to boric acid was investigated using the giant internodal cells of the charophyte alga Chara corallina (Klein ex Will. Esk. R.D. Wood). The advantage of this system is that it is possible to distinguish between membrane transport of boron (B) and complexing of B by plant cell walls. Influx of B was found to be rapid, with equilibrium between the intracellular and extracellular phases being established after approximately 24 h when the external concentration was 50 microM. The intracellular concentration at equilibrium was 55 microM, which is consistent with passive distribution of B across the membrane along with a small amount of internal complexation. Efflux of B occurred with a similar half-time to influx, approximately 3 h, which indicates that the intracellular B was not tightly complexed. The concentration dependence of short-term influx measured with 10B-enriched boric acid was biphasic. This was tentatively attributed to the operation of two separate transport systems, a facilitated system that saturates at 5 microM, and a linear component due to simple diffusion of B through the membrane. Vmax and Km for the facilitated transport system were 135 pmol m(-2) s(-1) and 2 microM, respectively. The permeability coefficient for boric acid in the Chara plasmalemma estimated from the slope of the linear influx component was 4.4 x 10(-7) cm s(-1) which is an order of magnitude lower than computed from the ether:water partition coefficient for B.

Oxidative stress and AP-1 activity in tamoxifen-resistant breast tumors in vivo

BACKGROUND

Most breast cancers, even those that are initially responsive to tamoxifen, ultimately become resistant. The molecular basis for this resistance, which in some patients is thought to involve stimulation of tumor growth by tamoxifen, is unclear. Tamoxifen induces cellular oxidative stress, and because changes in cell redox state can activate signaling pathways leading to the activation of activating protein-1 (AP-1), we investigated whether tamoxifen-resistant growth in vivo is associated with oxidative stress and/or activation of AP-1 in a xenograft model system where resistance is caused by tamoxifen-stimulated growth.

METHODS

Control estrogen-treated, tamoxifen-sensitive, and tamoxifen-resistant MCF-7 xenograft tumors were assessed for oxidative stress by measuring levels of antioxidant enzyme (e.g., superoxide dismutase [SOD], glutathione S-transferase [GST], and hexose monophosphate shunt [HMS]) activity, glutathione, and lipid peroxidation. AP-1 protein levels, phosphorylated c-jun levels, and phosphorylated Jun NH(2)-terminal kinase (JNK) levels were examined by western blot analyses, and AP-1 DNA-binding and transcriptional activities were assessed by electrophoretic mobility shift assays and a reporter gene system. All statistical tests are two-sided.

RESULTS

Compared with control estrogen-treated tumors, tamoxifen resistant tumors had statistically significantly increased SOD (more than threefold; P=.004) and GST (twofold; P=.004) activity and statistically significantly reduced glutathione levels (greater than twofold; P<.001) and HMS activity (10-fold; P<.001). Lipid peroxides were not significantly different between control and tamoxifen-resistant tumors. We observed no differences in AP-1 protein components or DNA-binding activity. However, AP-1-dependent transcription (P=.04) and phosphorylated c-Jun and JNK levels (P<.001) were statistically significantly increased in the tamoxifen-resistant tumors.

CONCLUSION

Our results suggest that the conversion of breast tumors to a tamoxifen-resistant phenotype is associated with oxidative stress and the subsequent antioxidant response and with increased phosphorylated JNK and c-Jun levels and AP-1 activity, which together could contribute to tumor growth.

Uterine arterial embolization: factors influencing patient radiation exposure

PURPOSE

To investigate patient radiation exposures during uterine arterial embolization and the factors responsible for those exposures.

MATERIALS AND METHODS

Clinical and procedural factors were evaluated for 42 consecutive procedures performed in 39 patients by one operator. Seven patients were excluded because of early termination (n = 1) or unusual conditions that necessitated extended procedures (n = 6). Fluoroscopic time, number of images acquired, height, and weight were available in the 35 remaining patients, and dose-area product (DAP) was available in 20. Equipment factors were evaluated by using a Lucite phantom in four angiography units from three manufacturers.

RESULTS

The mean fluoroscopic time per case decreased from 30.6 to 14.2 minutes between the 1st and 5th quintiles. Mean DAP decreased from 211.4 to 30.6 Gy. cm(2) with dose reduction techniques; this primarily reflected a decreased number of acquired images. Phantom studies demonstrated many significant dose variations with magnification and equipment position. Low-dose and pulsed fluoroscopic modes reduced exposure rates in units so equipped, but roadmapping caused a silent switch to continuous fluoroscopy in two such units, which doubled the exposure rate.

CONCLUSION

With operator experience and careful technique, uterine arterial embolization can be performed at radiation exposures comparable to those used in routine diagnostic studies. However, operators must be familiar with the technical parameters of their angiographic equipment.

Applying Nuclear Regulatory Commission guidelines to the release of patients treated with sodium iodine-131

OBJECTIVE

This article presents a brief synopsis of the 1997 regulations from the Nuclear Regulatory Commission concerning the release from the hospital of patients treated for thyroid disease with 131I. A simplified checklist is provided to demonstrate the instructions to patients and the new conditions for release of patients containing a higher level of 131I radioactivity than was allowed under the older regulations.

Permeability and channel-mediated transport of boric acid across membrane vesicles isolated from squash roots

Boron is an essential micronutrient for plant growth and the boron content of plants differs greatly, but the mechanism(s) of its uptake into cells is not known. Boron is present in the soil solution as boric acid and it is in this form that it enters the roots. We determined the boron permeability coefficient of purified plasma membrane vesicles obtained from squash (Cucurbita pepo) roots and found it to be 3 x 10(-7) +/-1.4 x 10(-8) cm s(-1), six times higher than the permeability of microsomal vesicles. Boric acid permeation of the plasma membrane vesicles was partially inhibited (30%-39%) by mercuric chloride and phloretin, a non-specific channel blocker. The inhibition by mercuric chloride was readily reversible by 2-mercaptoethanol. The energy of activation for boron transport into the plasma membrane vesicles was 10.2 kcal mol(-1). Together these data indicate that boron enters plant cells in part by passive diffusion through the lipid bilayer of the plasma membrane and in part through proteinaceous channels. Expression of the major intrinsic protein (MIP) PIP1 in Xenopus laevis oocytes resulted in a 30% increase in the boron permeability of the oocytes. Other MIPs tested (PIP3, MLM1, and GlpF) did not have this effect. We postulate that certain MIPs, like those that have recently been shown to transport small neutral solutes, may also be the channels through which boron enters plant cells.

9-cis-Retinoic acid suppresses mammary tumorigenesis in C3(1)-simian virus 40 T antigen-transgenic mice

Retinoids have been investigated as potential agents for the prevention and treatment of human cancers. These compounds play an important role in regulating cell growth, differentiation, and apoptosis. 9-cis-Retinoic acid (9cRA) is a naturally occurring ligand with a high affinity for both the retinoic acid receptors and the retinoid X receptors. We hypothesized that treatment with 9cRA would prevent mammary tumorigenesis in transgenic mice that spontaneously develop mammary tumors. To test this hypothesis, C3(1)-SV40 T antigen (Tag) mice, which develop mammary tumors by the age of 6 months, were treated daily p.o. with vehicle or two different dose levels of 9cRA (10 or 50 mg/kg) from 5 weeks to 6 months of age. Tumor size and number were measured twice each week, and histological samples of normal and malignant tissue were obtained from each mouse at time of sacrifice. Our results demonstrate that 9cRA suppresses mammary tumorigenesis in C3(1)-SV40 Tag-transgenic mice. Time to tumor development was significantly delayed in treated mice; median time to tumor formation for vehicle-treated mice was 140 days versus 167 days for mice treated with 50 mg/kg 9cRA (P = 0.05). In addition, the number of tumors per mouse was reduced by >50% in mice treated with 9cRA (3.43 for vehicle, 2.33 for 10 mg/kg 9cRA, and 1.13 for 50 mg/kg 9cRA, P < or = 0.002). Histological analysis of the mammary glands from vehicle and treated mice demonstrated that 9cRA treatment also did not affect normal mammary gland development. Immunohistochemical staining of normal and malignant breast tissue and Western blot analysis demonstrated that SV40 Tag expression was not affected by treatment with retinoids. Single doses of 10 and 50 mg/kg resulted in peak plasma concentrations of 3.4 and 6.71 microM, respectively. Daily doses of 9cRA for 28 days resulted in plasma concentrations of 0.86 and 1.68 microM, respectively, concentrations consistent with that seen in humans treated with 9cRA in clinical trials. These results demonstrate that 9cRA suppresses mammary carcinogenesis in transgenic mice without any major toxicity and suggest that retinoids are promising agents for the prevention of human breast cancer.

Chemoprevention of breast cancer

Despite a recent trend toward improvement in the U.S. breast cancer mortality rate, breast cancer incidence (182,800 new cases anticipated in 2000) and mortality figures (over 40,800 anticipated deaths) remain the highest and second highest, respectively, of all cancers in U.S. women. In 1998, the selective-estrogen-receptor-modulator (SERM) tamoxifen achieved positive results in the Breast Cancer Prevention Trial (BCPT), leading to the Food and Drug Administration (FDA) approval of tamoxifen for risk reduction in women at high risk of breast cancer (the historic first FDA approval of a cancer preventive agent). This brought about a paradigm shift in new approaches for controlling breast cancer toward pharmacologic preventive regimens, called chemoprevention. This paper presents a comprehensive clinical review of breast cancer prevention study, highlighting issues of the extensive study of tamoxifen. These issues include the record of primary tamoxifen results in several breast-cancer risk-reduction settings (primary, adjuvant, and ductal carcinoma in situ [DCIS]); critical secondary BCPT risk-benefit findings (including quality of life issues) and their effects on counseling patients on use of tamoxifen for prevention; ethic minorities; optimal tamoxifen dose/duration; and potential impact on mortality and other issues involved with potential net benefit to society. Other breast-cancer chemoprevention issues reviewed here include women at high genetic risk (especially BRCA1 mutation carriers); raloxifene in breast cancer prevention; other SERMs; SERM resistance; and new agents and combinations currently in development. Very recent developments involving PPAR-gamma ligands, COX-2 inhibitors, and RXR-ligands are discussed in the section on new drug development.

Permeability of boric acid across lipid bilayers and factors affecting it

Boron enters plant roots as undissociated boric acid (H(3)BO(3)). Significant differences in B uptake are frequently observed even when plants are grown under identical conditions. It has been theorized that these differences reflect species differences in permeability coefficient of H(3)BO(3) across plasma membrane. The permeability coefficient of boric acid however, has not been experimentally determined across any artificial or plant membrane. In the experiments described here the permeability coefficient of boric acid in liposomes made of phosphatidylcholine was 4.9x10(-6) cm sec(-1), which is in good agreement with the theoretical value. The permeability coefficient varied from 7x10(-6) to 9.5x10(-9) cm sec(-1) with changes in sterols (cholesterol), the type of phospholipid head group, the length of the fatty acyl chain, and the pH of the medium. In this study we also used Arabidopsis thaliana mutants which differ in lipid composition to study the effect of lipid composition on B uptake. The chs1-1 mutant which has lower proportion of sterols shows 30% higher B uptake compared with the wild type, while the act1-1 mutant which has an increased percentage of longer fatty acids, exhibited 35% lower uptake than the wild type. Lipid composition changes in each of the remaining mutants influenced B uptake to various extents. These data suggest that lipid composition of the plasma membrane can affect total B uptake.

A multihospital survey of radiation exposure and image quality in pediatric fluoroscopy

BACKGROUND

Traditionally, pediatric radiologists have been advocates of fluoroscopy systems that provide diagnostic images at the lowest possible radiation dose to the pediatric patient. Manufacturers of fluoroscopic equipment vary as to their claims of "low radiation" exposures.

OBJECTIVES

To obtain comparative data on radiation exposure and image quality from four pediatric hospitals, across variants of fluoroscopic equipment (such as pulsed versus continuous fluoroscopy).

MATERIALS AND METHODS

Images were acquired from phantoms that simulated the size of a 3-year-old child. Phantom results, both stationary and rotating dynamic, were evaluated for radiation exposure and for image resolution of high- and low-contrast objects.

RESULTS

Radiation exposure from the four fluoro units varied widely; the lowest-dose selectable fluoro mode produced exposures varying between 34 and 590 mrads/min among the four fluoro units, and the highest-dose selectable fluoro mode produced 540-2,230 mrads/min. The lowest radiation exposures were produced by pulsed fluoro units, and the very lowest radiation exposure was produced by a fluoroscope that had been especially optimized for pediatric imaging. There was only a small variation in image quality among the hospitals for visualization of stationary objects. A wide variability was noted for detection of objects on the moving phantom.

CONCLUSIONS

The variability in the number of detected objects was considerably smaller than the variability in radiation exposure. Pulsed fluoroscopy provides improved resolution for moving objects. Optimization of one hospital's fluoroscope especially for pediatric imaging produced the best ratio of image quality to radiation exposure.

Optimization of a fluoroscope to reduce radiation exposure in pediatric imaging

BACKGROUND

A new children's hospital provided the impetus to investigate radiation dose and image quality in a fluoroscope that was specially engineered for pediatric fluoroscopy. Radiation protection management recommends radiation exposures that are as low as reasonably achievable, while still maintaining diagnostic image quality.

OBJECTIVES

To obtain comparative phantom imaging data on radiation exposure and image quality from a newly installed fluoroscope before and after optimization for pediatric imaging.

MATERIALS AND METHODS

Images were acquired from various thickness phantoms, simulating differing patient sizes. The images were evaluated for visualization of high- and low-contrast objects and for radiation exposure. Effects due to use of the image intensifier anti-scatter grid were also investigated.

RESULTS

The optimization of the new fluoroscope for pediatric operation reduced radiation exposure by about 50% (compared to the originally installed fluoroscope), with very little loss of image quality. Pulsed fluoroscopy was able to lower radiation dose to less than 10% of continuous fluoroscopy, while still maintaining acceptable phantom image quality.

CONCLUSION

Radiation exposure in pediatric fluoroscopy can be reduced to values well below the exposure settings that are typically found on unoptimized fluoroscopes. Pulsed fluoroscopy is considered a requisite for optimal pediatric fluoroscopy.

The effect of gadolinium contrast media on radioiodine uptake by the thyroid gland

OBJECTIVE

Patients with thyroid cancer may require detailed anatomic imaging before 131I therapy. Imaging by contrast-enhanced CT is contraindicated because it may result in saturation of tissues with iodine, decreasing the avidity of thyroid or thyroid cancer cells to subsequent radioiodine for extended intervals. Gadolinium-enhanced MRI offers an alternative to CT for detailed anatomic imaging. However, it is not known whether gadolinium contrast affects uptake of iodine by the thyroid gland since lanthanides affect ion transport in a variety of ways. The objective of this project was to determine whether the gadolinium MRI contrast injection alters thyroid uptake of radioiodine.

METHODS

Radioiodine uptake by the thyroid gland was measured at 6 h and 24 h after the oral administration of 100 microCi 123I-Na-I. Three to seven days later, a standard dose (20 mL) of Magnevist (gadolinium DTPA) was administered intravenously. Another capsule of 100 microCi 123I Na-I immediately was given orally, and 6-h and 24-h radioiodine uptake by the thyroid gland was again measured and compared to baseline values.

RESULTS

There was no statistically significant difference in uptake of radioiodine uptake by the thyroid gland between baseline values and those acquired immediately after the administration of Magnevist.

CONCLUSION

Contrast-enhanced MRI may be safely performed before contemplated determinations of thyroid uptake of radioiodine, 131I therapy for hyperthyroidism, and postsurgical 131I imaging and therapy for well-differentiated thyroid cancer.

Emergency pre-hospital management of patients admitted with acute asthma

BACKGROUND

Little is known about the management of acute asthma prior to hospital admission. Pre-hospital treatment of patients referred to hospital with acute asthma was therefore studied in 150 patients divided into three groups: those in the Edinburgh Emergency Asthma Admission Service (EEAAS) who can contact an ambulance and present directly to respiratory services when symptoms arise (n = 38), those under continuing supervision at a hospital respiratory outpatient clinic (n = 54), and those managed solely in primary care (n = 58).

METHODS

Standardised admission forms detailing aspects of pre-hospital management, case records, GP referral letters, and ambulance patient transport forms were analysed.

RESULTS

In each group airflow obstruction had improved upon arrival at hospital, the effect being most marked in patients transported by ambulance (p<0. 001) and in those receiving nebulised beta(2) agonists prior to admission (p<0.005). However, 25% of patients arrived without having nebulised beta(2) agonists and 37% without having glucocorticoids. EEAAS patients were least likely to receive nebulised beta(2) agonists before arrival at hospital (p<0.05). This observation was attributable to a tendency for these patients to travel to hospital by car rather than by ambulance.

CONCLUSIONS

There is an important shortfall in administration of bronchodilators and glucocorticoids for acute asthma before arrival at hospital. Ambulances equipped with nebulised bronchodilators provide the optimal mode of transport to hospital for patients with acute asthma. In Edinburgh ambulances are not being used by a significant proportion of the population with asthma, possibly because of the mistaken belief that personal transport arrangements reduce journey time to hospital.

cJun overexpression in MCF-7 breast cancer cells produces a tumorigenic, invasive and hormone resistant phenotype

We have previously demonstrated decreased Jun/AP-1 activity in the breast cancer cell line MCF-7 when compared to normal or immortalized mammary epithelial cells. In this paper, we overexpress Jun in MCF-7 cells (MCF7Jun) and demonstrate that it results in diverse biologic and biochemical changes, which mimic those seen clinically in breast cancer. Overexpression of Jun causes significant alterations in the composition of AP-1, decreased junB and increased fra-1 expression and results in an increased biologic aggressiveness. MCF7Jun cells exhibit increased cellular motility, increased expression of a matrix degrading enzyme MMP-9, increased in vitro chemoinvasion and tumor formation in nude mice in the absence of exogenous estrogens. Furthermore, MCF7Jun cells are unresponsive to the growth stimulating effects of estrogen and growth inhibitory effects of tamoxifen. Analysis of the estrogen receptor (ER) expression and activity showed that the MCF7Jun cells have no detectable ER. MCF-7 cells overexpressing mutant forms of cJun were responsive to the growth stimulatory effects of estrogen indicating that full-length cJun is required to acquire the estrogen-independent phenotype in breast cancer cells.

Retinoic acid receptor antagonist BMS453 inhibits the growth of normal and malignant breast cells without activating RAR-dependent gene expression

To elucidate the role of RAR-dependent gene transcription in inhibiting breast cell growth, we have investigated the ability of retinoids to suppress growth of normal, immortal, and malignant breast cells. We compared the ability of all trans retinoic acid (atRA) to activate retinoid receptors in normal, immortal, and malignant breast cells, with its ability to inhibit the growth of these cells. Our studies demonstrate that normal breast cells are more sensitive to the growth inhibitory effect of atRA than are immortal nonmalignant breast cells and breast cancer cells. atRA activated RAR-dependent gene transcription in both atRA-sensitive and -resistant breast cells as determined by transfection of a RARE-containing reporter gene. These results demonstrate that activation of RAR-dependent gene transcription by atRA is not sufficient to inhibit growth in atRA-resistant breast cancer cells. To determine whether activation of RAR-dependent gene transcription by atRA is necessary for growth inhibition, we tested the growth suppressive effect of a retinoid (BMS453) which binds RAR receptors and transrepresses AP-1 but does not activate RAR-dependent gene expression. This retinoid inhibited the growth of normal breast cells (HMEC and 184) and T47D breast cancer cells. Breast cancer cells which were resistant to atRA, were also resistant to BMS453. Normal human breast cells were most sensitive to the anti-proliferative effects of BMS453. These results indicate that in some breast cells RAR-dependent transactivation is not necessary for retinoids to inhibit growth. Instead, retinoids may suppress growth by inhibiting transcription factors such as AP-1 through transcription factor crosstalk.

Measuring perceived 3D shape at multiple spatial scales

We present and test a novel multiscale representation of perceived 3D surface orientation: the orientation path. Using a multiscale probe, we measure perceived surface orientation at multiple spatial scales; linking the measurements for a given surface location yields that location's orientation path. The multiscale data obtained show that observers consistently see different surface orientations at different spatial scales. We demonstrate that such multiscale data can reveal multiscale differences between observers' percepts of a stimulus and the stimulus geometry. We also demonstrate the use of the orientation path in evaluating the multiscale effects of adding a depth cue to a 3D display.

Transgenically enhanced sorbitol synthesis facilitates phloem boron transport and increases tolerance of tobacco to boron deficiency

The mobility of elements within plants contributes to a plant species' tolerance of nutrient deficiencies in the soil. The genetic manipulation of within-plant nutrient movement may therefore provide a means to enhance plant growth under conditions of variable soil nutrient availability. In these experiments tobacco (Nicotiana tabacum) was engineered to synthesize sorbitol, and the resultant effect on phloem mobility of boron (B) was determined. In contrast to wild-type tobacco, transgenic tobacco plants containing sorbitol exhibit a marked increase in within-plant B mobility and a resultant increase in plant growth and yield when grown with limited or interrupted soil B supply. Growth of transgenic tobacco could be maintained by reutilization of B present in mature tissues or from B supplied as a foliar application to mature leaves. In contrast, B present in mature leaves of control tobacco lines could not be used to provide the B requirements for new plant growth. 10B-labeling experiments verified that B is phloem mobile in transgenic tobacco but is immobile in control lines. These results demonstrate that the transgenic enhancement of within-plant nutrient mobility is a viable approach to improve plant tolerance of nutrient stress.

Isotope ratio determination in boron analysis

Traditionally, boron (B) isotope ratios have been determined using thermal ionization mass spectrometry (TIMS) and, to some extent, secondary ion mass spectrometry (SIMS). Both TIMS and SIMS use a high-resolution mass analyzer, but differ in analyte ionization methods. TIMS uses electrons from a hot filament, whereas SIMS employs an energetic primary ion beam of Ga+, Cs+, or O- for analyte ionization. TIMS can be used in negative or positive ion modes with high sensitivity and precision of B isotope ratio determination. However, isobaric interferences may be a problem, if the sample is not well purified and/or memory of the previous sample is not removed. Time-consuming sample preparation, analyte (B) purification, and sample determination processes limit the applications of TIMS for routine analyses. SIMS can determine B and its isotope ratio in intact solid samples without destroying them, but has poorer resolution and sensitivity than TIMS, and is difficult to standardize for biological samples. Development of plasma-source mass spectrometry (MS) enabled the determination of B concentration and isotope ratio without requiring sample purification. Commonly used plasma-source MS uses an Ar inductively coupled plasma (ICP) as an ionization device interfaced to a low-resolution quadrupole mass analyzer. The quadrupole ICP-MS is less precise than TIMS and SIMS, but is a popular method for B isotope ratio determination because of its speed and convenience. B determination by ICP-MS suffers no spectroscopic interferences. However, sample matrices, memory effects, and some instrument parameters may affect the accuracy and precision of B isotope ratio determination if adequate precautions are not taken. New generations of plasma-source MS instruments using high-resolution mass analyzers provide better sensitivity and precision than the currently used quadrupole ICP-MS. Because of the convenience and high sample throughput, the high-resolution ICP-MS is expected to be the method of choice for B isotope ratio determination. The current state of instrumental capabilities is adequate for B isotope determination. However, precision and accuracy are primarily limited by sample preparation, introduction, and analytical methodology, including 1. Analyte loss and isotope fractionation during sample preparation. 2. The precision of B isotope determination in small samples, especially those containing low concentrations. 3. Difficult matrices. 4. Memory effects. Sample preparation by alkali fusion allows rapid and complete decomposition of hard-to-digest samples, but high-salt environments of the fused materials require extensive sample purification for B ratio determination. The alternative wet-ashing sample decomposition with HF also results in B loss and isotopic fractionation owing to the high volatility of BF3. Open-vessel dry- or wet-ashing methods usually do not work well for animal samples, and are also prone to B loss and contamination. Closed-vessel microwave digestion overcomes these problems, but the digests of biological materials have high C contents, which cause spectral interference on 11B and affect 11B/10B ratios. Exchange separation/preconcentration of B using exchange (cation or anion exchange, B-specific resin, e.g., Amberlite IRA-743) tend to cause B isotope fractionation, and C eluting from these resin columns may interfere with B isotope ratio determination. Memory effects of B that occur during sample determination may cause serious errors in B isotope ratio determination, especially when samples varying in B concentrations and/or isotope composition are analyzed together. Although the utilization of high-resolution plasma-source MS will undoubtedly improve analytical precision, it is the sample preparation, sample introduction, and analytical methodology that represent the primary limitation to accurate and precise B isotope ratio determination.