Expression Levels of Co-Regulators in Early Breast Cancer

Introduction: The p160 (SRC) family of estrogen receptor (ER) co-activators have important implications in tamoxifen resistance. The SRC family play a central role in ER mediated transcription. There are three family members; SRC-1, SRC-2 and AIB1. AIB1 is amplified in 5-10% of human breast cancers. SRC-1 expression is associated with HER2 expression, increased risk of recurrence and insensitivity to endocrine treatment. Co-factors interact with the ER and basal transcriptional machine to activate or repress ER-mediated transcription. To investigate the role of ER and its co-factors in breast cancer we have carried out quantitative RT-PCR (qRT-PCR) to measure the relative expression of ERa and its co-factors.Methods: In this study we examined patients which were untreated or treated with chemotherapy or hormonal therapy following breast conservation surgery. RNA was extracted from 340 early breast cancer specimens from the Edinburgh Breast Conserving Surgery cohort (BCS). The BCS is a fully documented consectutive cohort of breast cancers treated by conservation surgery, axillary node sampling or clearance, and whole breast radiotherapy between 1981-1998. Clinico-pathological features and complete follow up (duration >10 years) is available for this cohort. qRT-PCR was carried out using primers for ER, SRC-1, SRC-2, AIB1, NCoR1 and SMRT.Results: This study demonstrated SRC-1 expression to be negatively correlated with both SRC-2 and AIB1 expression. SRC-1 expression was also negatively correlated with the co-repressors NCoR1 and SMRT expression. There was a strong correlation between the co-repressors, NCoR1 and SMRT and the co-activators SRC-2 and AIB1. Relapse-free survival (RFS) was estimated using Kaplan-Meier curves. Patients who had high expression of all three co-activators had reduced relapse-free survival (HR: 2.15 95%C.I. 1.175-3.921, p=0.01). No significant association was noted with overall survival. Exploratory subgroup analysis was under powered and showed no significant association with outcome.Conclusion: In conclusion, our study of expression levels of ER and its cofactors by quantitative RT-PCR in breast cancer samples revealed a correlation between the co-factors and co-repressors. These findings would suggest that ER and cofactors may play a synergistic role in the development and progression of breast cancer.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2127.

The Expression of Insulin-Like Growth Factor-1 Receptor (IGF-1R) in Early Breast Cancer

Background: The insulin-like growth factor-1 receptor (IGF-1R) is expressed in normal breast epithelial cells and breast carcinomas. A number of studies have examined the over-expression of IGF-1R in breast cancer with the range of between 39% to 93%. However, many of these studies were carried out using ELISAs, radioimmunoassay with small patient cohorts. Phosphorylation of IGF-1R results in the activation of the MAPK and PI3K/Akt pathway. Activation of the PI3K/Akt pathway under the influence of IGF-1R plays an important role in maintaining the proliferation of breast cancer cells that are resistant to gefitnib, trastuzumab or chemoradiotherapy in vitro and in vivo. In the present study, we examined the expression of IGF-1R in early breast cancer and investigated the clinicopathological implications using immunohistochemistry and FISH.Methods: TMAs from a consecutive series (1981-98) of 1,812 women managed by wide local excision and postoperative radiotherapy (45Gy in 20-25 fractions) were collected following appropriate ethical review. Of 1686 cases stained, 198 received no adjuvant hormonal or chemotherapy, 1106 received tamoxifen only as adjuvant therapy and 144 received a combination of hormonal and chemotherapy. Median age at diagnosis was 56, 72% were post-menopausal, 23.9% node positive, median size was 1.5 cm. Samples were stained, using triplicate 0.6mm2 TMA cores for IGF-1R.Results: FISH for IGF1R gene amplification was successful in 343/408 cases (84%). Only 7 cases of IGF1R amplification were observed (2%). IGF1R expression was successfully evaluated in 1597 of 1686 (94.7%) cases. High levels of IGF-1R expression was weakly associated with tumour ER-a (correlation coefficient, 0.108; p=2.2 x 10-5) and PgR levels (correlation coefficient 0.162; p=1.86x10-10) and inversely correlated with EGFR expression (correlation coefficient -0.189; p=6.33x10-6). No association was noted between IGF1R expression and other molecular or clinical markers, such as tumour size. There was a trend for over-expression of IGF-1R to link with increased distant relapse free survival, particularly in ER positive breast cancers. This trend is time dependent, such that no difference in outcome is observed at 15 years.Conclusions: We have demonstrated in a large cohort of patients that IGF-1R gene amplification is a rare event, and over-expression is weakly associated with good prognostic features (ERa and PgR, lack of EGFR and better outcome).

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2128.

Effect of low-dose theophylline plus beclometasone on lung function in smokers with asthma: a pilot study

Smoking is common in asthma and is associated with worse asthma control and a reduced therapeutic response to corticosteroids. The present authors hypothesised that treating smokers with asthma with low-dose theophylline added to inhaled corticosteroids would enhance steroid sensitivity and thereby improve lung function and symptoms. In a double-blind, parallel group exploratory trial, 68 asthmatic smokers were randomised to one of three treatments for 4 weeks: inhaled beclometasone (200 microg day(-1)), theophylline (400 mg day(-1)) or both treatments combined. Outcome measures included change in lung function and Asthma Control Questionnaire (ACQ) scores. At 4 weeks, theophylline added to inhaled beclometasone produced an improvement in peak expiratory flow (39.9 L min(-1), 95% confidence intervals (CI) 10.9-68.8) and ACQ score (-0.47, 95% CI -0.91- -0.04) and a borderline improvement in pre-bronchodilator forced expiratory volume in one second (mean difference 165 mL, 95% CI -13-342) relative to inhaled corticosteroid alone. Theophylline alone improved the ACQ score (-0.55, 95% CI -0.99- -0.11), but not lung function. In the present pilot study, the combination of low-dose theophylline and inhaled beclometasone produced improvements in both lung function and symptoms in a group of smokers with asthma. Larger trials are required to extend and confirm these findings.

Role of symptoms and lung function in determining asthma control in smokers with asthma

BACKGROUND

Cigarette smoking in asthma increases the severity and accelerates the decline in lung function. The relative role of symptoms and lung function in determining asthma control in smokers with asthma is not known.

AIM OF THE STUDY

The aim of this study was to compare asthma control in smokers vs never-smokers with asthma, using the validated Juniper asthma control questionnaire (ACQ), and assess if any difference was because of a particular symptom or the forced expiratory volume in one second (FEV(1)) value.

METHODS

This was a cross-sectional study of 134 asthmatics (74 never-smokers and 60 smokers) with >or=15% reversibility in FEV(1) after salbutamol. All subjects completed the ACQ, recording FEV(1) and asthma symptoms (night awakening, morning symptoms, dyspnoea, wheeze, activity limitation and use of reliever inhaler).

RESULTS

Compared with the never-smokers, smokers with asthma had significantly worse median (IQR) total asthma control score [1.6 (1.1-2.3) vs 2.8 (1.7-3.4); (P < 0.0001)] and in each of the six individual symptom question scores (P < 0.001), but no difference in FEV(1) levels (P = 0.908).

CONCLUSION

Asthma control is significantly worse in asthmatics who smoke compared with never-smokers, with all symptoms related to asthma control uniformly worse in smokers, independent of FEV(1).

Peroxisome proliferator-activated receptor-gamma agonists as potential anti-inflammatory agents in asthma and chronic obstructive pulmonary disease

Inhaled corticosteroids are the most effective therapy for chronic persistent asthma and have a role in the treatment of chronic obstructive pulmonary disease (COPD). However, corticosteroids have reduced efficacy in some patients with asthma and fail to halt the progressive deterioration in lung function characteristic of COPD. Additional or alternative drug treatments to corticosteroids are required to improve control of inflammation in patients with therapy resistant airway disease. Peroxisome proliferator-activated receptor-gamma (PPAR-gamma) agonists have displayed potent anti-inflammatory properties in experimental models of asthma and other airway diseases and as a result have the potential to become an additional treatment for asthma and COPD. We review the evidence from these experimental models and their applicability to asthma and COPD and the requirements for future clinical and experimental research.

Effects of smoking cessation on lung function and airway inflammation in smokers with asthma

RATIONALE

Active smoking in asthma is associated with worsening of symptoms, accelerated decline in lung function, and impaired response to corticosteroids.

OBJECTIVES

To examine the short-term effects of smoking cessation on lung function, airway inflammation, and corticosteroid responsiveness in smokers with asthma.

METHODS AND MEASUREMENTS

Smokers with asthma were given the option to quit or continue smoking. Both groups underwent spirometry and induced sputum at baseline and at 1, 3, and 6 wk. Cutaneous vasoconstrictor response to topical beclometasone, airway response to oral prednisolone, and sensitivity of peripheral blood lymphocytes to corticosteroids were measured before smoking cessation and at 6 wk.

MAIN RESULTS

Of 32 subjects recruited, 11 opted to continue smoking (smoking control group). Of 21 subjects who opted for smoking cessation, 10 quit smoking for 6 wk (quit group). In the comparison of quitters with smokers at 6 wk, the mean (confidence interval [CI]) difference in FEV(1) was 407 ml (21, 793), p = 0.040, and the proportion of sputum neutrophils was reduced by 29 (51, 8), p = 0.039. Total cutaneous vasoconstrictor response score to topical beclometasone improved after smoking cessation with a mean (CI) difference of 3.56 (0.84, 6.28), p = 0.042, between quitters and smokers. There was no change in airway corticosteroid responses after smoking cessation.

CONCLUSIONS

By 6 wk after smoking cessation, subjects who quit smoking had achieved considerable improvement in lung function and a fall in sputum neutrophil count compared with subjects who continued to smoke. These findings highlight the importance of smoking cessation in asthma.

The influence of smoking on the treatment response in patients with asthma

PURPOSE OF REVIEW

Cigarette smoking and asthma are associated with poor symptom control and impaired therapeutic responses to corticosteroids. We summarize the clinical evidence for corticosteroid resistance, the mechanisms which could be responsible and potential management of this resistance. We also consider the effect smoking has on other drugs commonly used to treat patients with asthma.

RECENT FINDINGS

In most developed countries the prevalence of active smoking in adults with asthma is about 25%. Compared with nonsmokers with asthma, active smokers have more severe asthma symptoms, accelerated decline in lung function and impaired short-term therapeutic responses to corticosteroids. The mechanism of corticosteroid resistance in smokers with asthma is currently unexplained but could be due to alterations in airway inflammatory cell phenotypes, changes in glucocorticoid receptor alpha to beta ratio, and reduced histone deacetylase activity. Cigarette smoking also increases the clearance of drugs such as theophylline by induction of metabolizing enzymes. Alternative or additional treatment to inhaled corticosteroids may be required for individuals with asthma who are unable to stop smoking or who have persistent symptoms following smoking cessation.

SUMMARY

Smokers with chronic asthma have a reduced response to short-term corticosteroid therapy. Every effort should be made to encourage individuals with asthma who smoke to stop. Alternative or additional therapies to inhaled corticosteroids are needed for individuals with asthma who are unable to quit smoking.