Short/long-term cryopreservation prior to comet assay of whole-blood leukocytes and in vitro-cultured lung fibroblasts

Single-cell gel electrophoresis (comet assay) is a valuable test that can be used in ecotoxicological, epidemiological, and biomonitoring contexts. We assessed the effects of short- (without cryopreservation) and long-term (with cryopreservation) storage of DMEM-cultivated human peripheral blood leukocytes (HPBLs) and a human lung fibroblast cell line (FLECH-104) on comet assay results. Samples were stored for 6 or 24 h at room temperature (23°С) or 4 °C and frozen at -80 °C or -196 °C for 1, 2, or 4 weeks. Short-term storage led to significant increases in the comet tail intensity (TI) and Olive tail moment (OTM) in HPBL and FLECH-104 samples. Freezing FLECH-104 samples at -80°С and -196°С resulted in TI mean increases, with no differences in OTM. All frozen HPBL samples did not exhibit significant increases in TI or OTM, and instead exhibited a slight decrease in TI versus the control at both -80 °C and -196 °C. Increased frequency of highly damaged cells was observed in FLECH-104 and HPBL cultures during both short-term storage and after freezing, which may indicate a significant destructive effect. Therefore, freezing of cell cultures and whole blood according to our protocol is not recommended.

[Limb-shaking transitory ischaemic attack in a patient with subocclusion of the internal carotid artery]

Described in the article is a clinical case report concerning symptomatic subocclusion of the internal carotid artery in a male patient with a rare variant of recurrent limb-shaking transitory ischaemic attacks (LS-TIA). The patient presented with a three-month history of episodes of involuntary jerky movements in his left hand. These episodes occurred invariably on assuming a vertical position. The findings of duplex scanning revealed subocclusion of the right internal carotid artery. The patient was subjected to stenting with the use of the system of proximal cerebral protection. The postoperative period was complicated by the development of cerebral hyperperfusion syndrome the risk of which in patients with LS-TIA is known to be elevated. Via telephone interviewing carried out at 1, 6 and 12 months after the intervention, the patient confirmed that the episodes of hand shaking did not recur. This case report highlights the importance of accurately assessing the clinical findings while selecting patients for carotid revascularization, since such ischaemic episodes are strongly suggestive of a severe lesion of the contralateral carotid artery. Once subocclusion is revealed, it is optimal to perform stenting with the use of a system of proximal protection, as a safer and more effective method of surgical revascularization in such conditions.

[Retrograde type A aortic dissection after endovascular repair of the thoracic artery]

Retrograde type A aortic dissection is a severe and prognostically unfavourable complication of endovascular repair of the thoracic aorta. The aim of the present article is to describe a clinical case report concerning a hybrid operative intervention for retrograde type A aortic dissection in a patient having endured two-stage endovascular repair of the thoracic artery.

Abstract P5-09-01: Comprehensive gene assessment of estrogen receptor positive breast cancer reveals that HER2 plays an important role in resistance to neoadjuvant letrozole

Background

10% of all breast cancers are HER2+/ER+ and these cancers exhibit both intrinsic and acquired resistance to endocrine therapy. They have a worse prognosis than HER2-/ER+ cancers.

Aims

1. To investigate the role of HER2 in response to neoadjuvant Letrozole.

2. To predict which HER2+ cancers do not respond to Letrozole.

Methods

23 postmenopausal women with large, operable, locally advanced HER2+/ER+ breast cancer treated with neoadjuvant Letrozole had response assessed by periodic 3D ultrasound. Core biopsies taken at 0, 14 days and 3 months of treatment. RNA were extracted, amplified, labelled and hybridised to Illumina HT-12 whole genome beadarrays. A group of patients with ER+/HER2- disease were identified to compare clinical and molecular response.

Results

13 (57%) HER2+/ER+ patients responded (R) and 10 (43%) patients did not (NR). HER2 expression was significantly higher at baseline in the NR group (p = 0.005). There were differences in gene expression between HER2+/ER+ R and NR and between the HER2+/ER+ and HER2-/ER+ NR groups. In the HER2+/ER+ NR group, there was virtually no change in gene expression during treatment with Letrozole.

Table 1  Up Regulated GenesDown Regulated Genes n0-14 days14 days-3 months0-3 months0-14 days14 days-3 months0-3 monthsHER2-ve Responders43122833505127213HER2-ve Non Responders1588361432340129HER2+ve Responders13541272703831125HER2+ve Non Responders10851117106

Considerable gene changes with overlap in the genes that changed most was evident in HER2+/ER+ and HER2-/ER+ responders.

Analysis of 55 estrogen sensitive proliferation genes revealed significantly less reduction in the HER2+/ER+ NR group than in the HER2+/ER+ R group (AUC = 10.57 vs 27.93 respectively; p<0.0001). This difference was apparent by 14 days (AUC = 25.55 vs 17.94; p = 0.005).

The HER2+/ER+ NR group had significantly less reduction in these 55 estrogen sensitive proliferation genes when compared to the HER2-/ER+ NR group at 14 days (AUC = 17.94 vs 18.05 respectively; p = 0.0007) and by 3 months (AUC = 10.57 vs 26.26; p<0.0001).

In logistic regression analysis, HER2 status was predictive of disease progression (p = 0.048). A single gene classifier predicted response to endocrine therapy in the ER+/HER2+ group. This was accurate in 94% of patients in the test set (n = 23). This classifier was also predictive of progression free survival (p = 0.006) in HER2+/ER+ patients.

Conclusions

In this large cohort of patients treated with neoadjuvant letrozole:

• HER2+/ER+ cancers have a low rate of response.

• Changes in gene expression are similar in HER2+/ER+ and HER2-/ER+ responders.

• HER2+/ER+ cancers that do not respond to letrozole have few gene changes and little reduction in estrogen signalling pathways.

• In contrast HER2-/ER+ non responders show significant gene changes and reduced expression of estrogen sensitive proliferation genes.

• A single gene classifier at diagnosis in ER+/HER2+ has been identified which predicts response to Letrozole with 94% accuracy.

• Validation continues. This single gene classifier may provide a simple test to predict which HER2+/ER+ cancers are endocrine resistant.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-09-01.

Abstract PD3-2: Accurate and robust prediction of clinical response to aromatase inhibitors by two weeks of neoadjuvant breast cancer treatment

Background: Aromatase inhibitors (AIs) have an established role in the treatment of estrogen receptor alpha positive (ER+) post-menopausal breast cancer. Response rates are 50-70% in the neoadjuvant setting and lower in advanced disease. There is a need to identify biomarkers to predict response that outperform those currently available, to be able to offer more stratified treatments and improved patient care.

Methods: Pre- and on-treatment (at 14 days and 3-months) biopsies were obtained from 89 post-menopausal women with ER+ breast cancer receiving 3 months of neoadjuvant Letrozole. Illumina Beadarray gene expression data (n = 34) were combined with Affymetrix GeneChip data (n = 55) and cross-platform integration approaches developed as part of this study were implemented to combine data. Dynamic clinical response was assessed for each patient using periodic 3D ultrasound measurements performed during treatment. A gene classifier was developed from pre and 14 day gene array expression data to predict response. An independent series from the Royal Marsden was used to validate the classifier.

Results: Response to endocrine therapy in the neoadjuvant setting based on the expression of 4 genes has been developed. The classifier comprises baseline expression of an immune signalling gene and an apoptosis related gene, together with 14 day expression of two proliferation genes. Early on-treatment gene changes in combination with pre-treatment gene expression significantly improve predictive power compared to pre-treatment gene expression alone. The classifier had a 96% accuracy in a training dataset (n = 73) and 91% accuracy in an independent validation dataset (n = 44) dataset.

Table 1 AccuracySensitivitySpecificityPPVNPVAUC (ROC)Training0.960.890.980.890.960.96Validation0.910.80.970.920.9NASensitivity and specificity of model in training and validation datasets

Expression of the pre-treatment immune signalling gene alone predicted for response with 85% and 82% accuracy in training and validation datasets respectively. Higher pre-treatment levels of this gene were associated with a significantly better 1 year progression free survival (PFS) (P = 0.0001). In a larger series of patients treated with neoadjuvant Letrozole (n = 129) higher expression of this gene alone was associated with a significantly improved 10 year RFS (p = 0.0359). In a separate tamoxifen treated cohort (n = 212) higher expression of this gene at diagnosis was associated with a significantly improved 5 year (p = 0.0015) and 10 year (p = 0.04) recurrence free survival (RFS).

Conclusion:

• A 4 gene classifier has been developed and validated to predict response to neoadjuvant Letrozole.

• One of the genes identified is a significant predictor in independent data sets of long term RFS in endocrine treated patients.

• This new classifier has the potential to predict accurately the benefit of endocrine therapy and has huge potential clinical value.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr PD3-2.

Abstract P6-04-09: Lack of response to aromatase inhibitors involves distinct mechanisms

Background: Estrogen is a key hormone involved in cancer cell development. It forms a complex with estrogen receptor alpha (ER) which binds to estrogen response elements (EREs) in the promoter regions of genes under its transcriptional control. Letrozole inhibits local production of estrogen. Despite the prevalent use of such drugs little is known about their effect at molecular and transcriptomic level. A better understanding of the molecular mechanisms underlying why approximately 75% of ER rich cancers respond might help to elucidate the mechanisms characterising a lack of response in some patients.

Methods: A new gene expression dataset was generated from sequential core biopsy/theatre samples (before treatment, 10–14 days on treatment and at surgery) taken from ER+ patients undergoing neo-adjuvant letrozole treatment. Clinical response to treatment was assessed by changes in tumour volume based on 3D ultrasound (performed by a single operator).

Results: On letrozole the majority of ER+ tumours respond with dramatic early transcriptomic changes. A significant reduction in proliferation is seen through down-regulation of key cell cycle control genes such as CyclinD1, CyclinA, CyclinB1, CyclinB2 and CDK2, and genes involved with the initiation phase of DNA replication such as the MCM complex. Several of these (including CyclinD1, CyclinB2 and MCM2) have been shown to contain candidate ERE sequences in their promoter region and therefore down-regulation of these would be concordant with deprivation of estrogen. There is also a significant up-regulation of genes including collagens, lamanins, integrins and others involved with intra-cellular adhesion and extra-cellular matrix (ECM) remodelling. Preliminary analysis suggests the involvement of a local immune response as a potential mechanism for tumour cell death, as genes involved with antigen presentation, leukocyte trans-endothelial mediation, natural killer cell mediated cytotoxicity and T-cell mediated cell death are significantly up-regulated within the clinically responding group.

Two distinct subsets were seen in non-responders. The first subgroup shows a ‘classical non-response profile’ with very little change in expression of genes involved with cell cycle, ECM remodelling, cellular adhesion and antigen presentation between baseline and 14-days of treatment. The second subgroup have a gene expression profile similar to the responding group with a down-regulation of cell cycle and up-regulation of genes involved with ECM remodelling, cellular adhesion and antigen presentation. Whether these are true non-responders is not clear.

Conclusion: Approximately half of clinically non-responding patients have molecular profiles similar to responding patients whilst the other half have a distinct pattern of expression with significantly less change in genes associated with cell cycle control, ECM remodelling, intra-cellular adhesion and antigen presentation. On-going work will elucidate long term outcomes in these two groups.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P6-04-09.

Abstract P6-04-06: Inverse regulation of Neuregulin1 and HER-3 during treatment with aromatase inhibitors of estrogen receptor-positive breast cancer

Background: Resistance to endocrine therapy may be promoted by deregulation of growth factor signaling pathways in addition to its intimate bidirectional crosstalk with the estrogen receptor (ER) signaling pathway. We have previously shown HER-2/neu mRNA upregulation in HER-2/neu non-amplified tumors responding to therapy with aromatase inhibitors (AIs) [1]. Targeting HER-downstream signaling pathways may represent a strategy to overcome acquired endocrine resistance. Here, we aim at exploring the effect of treatment with AIs on the HER-receptor family members and the HER-3/-4 ligand neuregulin1 (NRG1) in ER+ breast cancers.

Methods: Matched tumor biopsies were collected from 85 ER+ breast cancers before and after three months of neo-adjuvant treatment with the AIs letrozole or anastrozole. For 64 of the patients, tumor biopsies were also available at two weeks of treatment. The patients were classified as either responders or non-responders depending on more or less than 50% reduction in tumor size, respectively. RNA was extracted from tumors and mRNA expression analyses of HER-1-4 and NRG1 were performed by real-time PCR using gene-specific primers. Changes in mRNA levels during treatment were estimated using the non-parametric Wilcoxon sign-rank test, while the correlations between mRNA levels were analyzed using 2-tailed Spearman rank test.

Results: Among all the ER+ HER-2/neu non-amplified tumors we observed a significant increase in mRNA expression of EGFR/HER-1 (51/64 tumors, p < 0.001) and NRG1 (49/63, p < 0.001) during three months of treatment with AIs. The increased expressions were most prominent in the time interval from two weeks to three months of treatment (p < 0.001 for both). In contrast, HER-3 decreased significantly during treatment (p = 0.023, 27 up and 39 down). Consequently, changes in NRG1 during treatment correlated negatively with HER-3 (r = −0.274, p = 0.036) and positively with EGFR/HER-1 (r = 0.557, p < 0.001). Interestingly, in a subgroup of patients responding to treatment, HER-3 increased during the first two weeks of treatment (21 up and 8 down; p = 0.031) followed by a decrease (10 up and 19 down; p = 0.033) from two weeks to three months of treatment.

Discussion: We report an increase in NRG1 expression during estrogen deprivation. This may be explained by a biological reprogramming causing the cells to be more sensitive to mitogenic signals. Elevated NRG1 level activates the HER-2/neu:HER-3 complex in tumors which in ovarian cancer lead to downregulation of HER-3 [2]. In line with this, we observed downregulation of HER-3 in tumors with increased NRG1 expression. As EGFR/HER-1 is known to be transcriptionally repressed by estrogen, it is conceivable that the stimulation of EGFR/HER-1 is caused by estrogen depletion. We propose that treatment with AIs leads to increased signaling through the HER-2/neu:HER-3 complex in ER+ HER2/neu non-amplified breast tumors.

1. Flageng, M.H., L.L. Moi, J.M. Dixon, J. Geisler, E.A. Lien, W.R. Miller, P.E. Lonning, and G. Mellgren, Br J Cancer, 2009.101: 1253–60. 2. Makhija, S., L.C. Amler, D. Glenn, F.R. Ueland, M.A. Gold, D.S. Dizon, V. Paton, C.Y. Lin, T. Januario, K. Ng, A. Strauss, S. Kelsey, M.X. Sliwkowski, and U. Matulonis, J Clin Oncol, 2010. 28:1215–23.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P6-04-06.

Abstract P3-06-23: Predicting response to neoadjuvant letrozole

Background: Approximately 75% of older postmenopausal patients with large operable or locally advanced oestrogen receptor positive breast cancer respond to treatment with neoadjuvant letrozole. Prediction of response is required as approximately 25% fail to respond. The aim of this study was to design a response predicting classifier with two data sets, one published previously [1] and secondly a new dataset.

Methods: Patients were treated with Letrozole (Femara, 2.5 mg daily) and tissues were collected before treatment, 2 or 3 weeks on treatment, and between 3 and 5 months on treatment. Response was based on a 3D ultrasound, with response being classified as a 50% reduction in tumour volume at 3 months. To ensure biological relevance of the response groups we also separated patients into Quick Stable Responders (QSR) and Long-Term Non-responders (LNR), as summarised in Table 1.

Abstract P6-04-10: Comprehensive gene and protein assessment of the role of Her2 in the response to neoadjuvant Letrozole suggests patients without amplification may also benefit from anti-Her2 treatment

Background: Older postmenopausal patients with large operable or locally advanced oestrogen receptor positive, invasive breast cancers are candidates for treatment with neoadjuvant letrozole. HER2 positivity is a potential marker for early endocrine therapy resistance. In this study we have evaluated the effects of HER2 amplification, gene and protein expression at diagnosis and following 14 and 90 days of treatment with neoadjuvant Letrozole.

Methods: 70 postmenopausal women with large operable and locally advanced oestrogen receptor (ER) positive invasive breast cancers were treated with neoadjuvant letrozole. Response was assessed by 3D ultrasound. Sequential core biopsies were taken at 0, 14 days and 3 months of treatment. 12 patients were HER2 positive (either 3+ or 2+ FISH positive), 20 were HER2 2+ FISH negative and 38 were HER2 negative (0 or +).

Results: 43 patients were responders to letrozole and 17 were non-responders. 7 of the 17 non-responders were HER2 positive. Analysing response in two groups (HER2 2+ and 3+ together versus 0 or +) there was a greater difference in response rate between these two groups than when splitting into conventional HER2 positive and negative groups (P < 0.0001). In non-responding patients HER2 gene expression levels from the microarrays taken at baseline were significantly higher than the HER2 expression in responding patients (p = 0.01). There was also an increase in HER2 gene expression seen during the first 14 days of treatment in non-responding but not responding patients (p = 0.08). Rank product analysis of gene expression identified 34 down-regulated genes and 7 up-regulated genes which were shared between the HER2 2+ FISH negative samples and samples which were HER2 3+ or HER2 2+ FISH positive.

Conclusion: This large cohort of patients treated with neoadjuvant letrozole shows that:

HER2 expression correlates with response to letrozole.

A better cut off for prediction of response to letrozole is the split between 0 and + versus 2+ and 3+ rather than the traditional 3+.

Patients with increased MRNA expression at diagnosis for HER2 have a significantly lower response rate to neoadjuvant letrozole.

Endocrine therapy together with anti-HER2 therapies should be considered for patients having neoadjuvant endocrine therapy for cancers which over express HER2.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P6-04-10.

[Stabilization of cellular membranes as a target of vascular therapy]

We present data of the study of effect of trimetazidine MB on the state of cellular membranes assessed on lymphocytes as highly sensitive model of hypoxia and endothelial dysfunction. Detection of external cytoplasmatic membrane blebbing and registration of quantity of membrane released microparticles by the method of phase-contrast microscopy were carried out in groups of patients with hypertensive disease without and with ischemic heart disease (IHD). It was found that number of cells in the state of terminal blebbing statistically significantly decreased and number of cells with intact cytoplasmic membrane increased at the background of intake of trimetazidine in all groups of patients. With correlation coefficient 0.76 (p<0.05) between content of membrane microparticles and terminal blebbing lowering of content of membrane released microparticles was noted in peripheral blood of patients of all studied groups. The investigation conducted allows to make conclusion that stabilization of cellular membranes is one of spectra of trimetazidine actions underlying improvement of self feeling of patients with vascular pathology.

[Modulation of membrane blebbing and microparticle sheddimg as a target of cardiovascular prophylaxis]

Physicocemical and antigenic properties of peripheral blood lymphocytes and shed membrane microparticles were studied in patients with CHD and angina of effort and in those with hypertensive disease. The frequency of lymphocyte blebbing in CHD and angina patients was significantly higher than in those with HD (70.56, 52, 25.7% respectively). Incubation with rotenone and zymosan resulted in an increase of lymphocyte blebbing to 77.34 and 86.5% vs the initial level of 70.56% (p < 0.05). Patients of both groups had an increased number of membrane microparticles in peripheral blood (59.6 and 78.2 U/4 cm2 respectively). It is concluded that modulation of Imphocyte blebbing and microparticle shedding may be a promising target of cardiovascular prophylaxis.

Abstract P4-02-02: Epidermal Growth Factor Receptors (ErbB/HER) and the Ligand Neuregulin 1 (NRG1) Increase in Breast Tumors during Short Time Endocrine Treatment

Background: Cross-talk between estrogen receptor (ER) and growth factor signaling pathways has been suggested to play a role in development of resistance to endocrine treatment with tamoxifen or aromatase inhibitors (AIs). While HER-2/neu amplification has been associated with lack of endocrine sensitivity in ER+ breast cancer, recent data have suggestedanti-HER-2 therapy to enhance efficacy of AIs in a subset of HER-2/neu non-amplified breast cancers [1], and we found HER-2/neu upregulation in tumors responding to therapy with AIs [2]. Here, we aimed at exploring the effect of treatment with AIs on other components of the HER family, including NRG1, recently reported to be subject to silencing through promoter methylation in breast cancers [3].

Methods: Tumor biopsies were collected from 60 ER + breast cancers before and after 3 months treatment with the AIs, Anatrozole or Letrozole. Tumor biopsies after 2 weeks of treatment were available for 39 of the patients. RNA was extracted from the tumors and mRNA expression analysis of HER-1, HER-2/neu, HER-3, HER-4 and NRG1 were performed with gene-specific primers and probes by real-time PCR. Changes in mRNA expression during treatment were analyzed by Wilcoxon Sign Rank tests, and correlation between expression groups by Spearman correlation.

Results: Among HER-2/neu non-amplified tumors (n=56), we observed a significant increase in mRNA expression for HER-1 (40/50 tumors; mean increase 2.0-fold) and NRG1 (38/54 tumors; mean increase 2.9-fold) during treatment independent of treatment response (P&lt;0.001 for both). A non-significant increase in Her-2/neu was observed in 28/54 tumors (18/38 responders). Interestingly, individual alterations in tumor HER-2/neu correlated negatively to change in HER-1 (R=-0.414, p=0.001). Data on DNA methylation at the NRG1 gene will be presented. While no statistical significant increase or decrease in HER-3 or -4 were observed, individual variations in these two parameters were statistically correlated among individual tumors (R=0.621, P&lt;0.001).

Conclusions: Estrogen suppression with use of AIs significantly increased intratumor expression levels of HER-1 and NRG1 in HER-2/neu non-amplified tumors, while HER-2/neu increased in a subset of tumors. These findings suggest extensive cross-talks between estrogen stimulation and the HER system, indicating potential mechanisms of therapy resistance. The increase in NRG1 during treatment with AIs may represent a cellular response that leads to changes in its tumor suppressor activity. These findings merits further explorations.

1. Johnston, S., et al., Lapatinib combined with letrozole versus letrozole and placebo as first-line therapy for postmenopausal hormone receptor-positive metastatic breast cancer. J Clin Oncol, 2009. 27(33): p. 5538-46.

2. Flageng, M.H., et al., Nuclear receptor co-activators and HER-2/neu are upregulated in breast cancer patients during neo-adjuvant treatment with aromatase inhibitors. Br J Cancer, 2009. 101(8): p. 1253-60.

3. Chua, Y.L., et al., The NRG1 gene is frequently silenced by methylation in breast cancers and is a strong candidate for the 8p tumour suppressor gene. Oncogene, 2009. 28(46): p. 4041-52.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P4-02-02.

Abstract P4-02-03: Gene Copy Number Alterations Related to mRNA and miRNA Expression in Endocrine Resistant Breast Cancers

Background

Endocrine resistance is a major clinical issue in breast cancer. Multiple studies provide data relating molecular features of primary tumours on their response to endocrine treatment. However, there is a paucity of data on molecular profiles of breast tumours at time when endocrine resistance has already manifested.

Aim

Provide multilayer molecular profiling of a series of breast tumours at time of relapse or progression on endocrine treatment.

Results

High density microarray-comparative genomic hybridisation (aCGH) analysis was performed in 39 endocrine treated breast tumours at time of progression or relapse. 25 of these tumours were also profiled using whole genome mRNA and miRNA arrays (HT-12 mRNA array and DASL Sentrix Array Matrix micro-RNA array, Illumina).

Overall the aCGH profiles of resistant tumours were similar to aCGH profiles of un-selected luminal breast tumours and cell lines published earlier. The most common gene copy gain areas (&gt;10M of length) were located in 1q23.1-44, 5p13.1-33, 8p11.23-q24.3, 16p12.1-13.3, 17q21.33-24.1 and 20q13.2-13.33, while the most common losses were in 1p33-36.32, 8p12-23.3, 11q22.3-24.1, 16q12.2-24.3 and 17p11.2-13.3. Unsupervised hierarchical clustering by gene copy number profiles split of the resistant tumours into 3 groups. As expected, on average mRNAs and microRNAs were higher expressed in tumours carrying gains of their genes and were decreased in tumours carrying the losses. Copy number gains in this series were associated with the upregulation of multiple RNAs, including C8orf76, TATDN1, CYC1, ZBTB10, C16orf63, THUMPD1, TFB2M, miR-454, miR-301a and miR-296-3p/5p. Losses were associated with the downregulation of RNAs including ACADVL, BNIP3L, UBE4A, REXO2, ATP5L, PPP2CB, NBL1 and PCM1. Of the above genes UBE4A and ATP5L are closely co-localised in 11q23.3; miR454-miR301a are located closely in 17q22. Such associations suggest that changes in expression of these genes in breast cancers may be driven by alterations in the gene copy number. Analysis of the recurrent amplification regions on this dataset is underway.

Conclusions

aCGH profiles of endocrine resistant tumours at time of relapse or progression are similar to those found in un-selected and non-treated luminal tumours. The study provides the first dataset integrating gene copy number with mRNA and microRNA gene expressions in clinical specimens of endocrine resistant breast cancers.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P4-02-03.

Sequential changes in gene expression profiles in breast cancers during treatment with the aromatase inhibitor, letrozole

The study aim was to identify early (within 14 days) and late changes (by 3 months) in breast cancer gene expression profiles associated with neoadjuvant therapy with letrozole. RNA from sequential tumour biopsies in 54 patients was analyzed on microarrays; changes were determined by frequency, magnitude and significance analyses. Substantially more genes were changed at 3 months (1503) than at 14 days (237). Early changed genes were associated with cell cycle (downregulation), blood vessel development and extracellular matrix (upregulation); late changes included 'cellular metabolic process', 'generation of precursor metabolites and energy' (decreased) and 'cell adhesion' 'biological adhesion' (increased). A striking difference between the early and late changes was the general location of downregulated genes-nuclear structures at 14 days and mitochondria after 3 months. These changes in gene expression profiles provide a new and important database by which to understand molecular mechanisms of letrozole in breast cancers.

miRNA Profiling of Endocrine-Resistant Breast Tumours

RationalemiRNAs are a relatively recently discovered class of molecules with major implications in cellular biology, including tumorigenesis; yet little is known about their possible involvement in the development of endocrine resistance in breast cancer. The aim of this study was to identify sub-groups of endocrine-resistant tumours with distinctive miRNA profiles.Methods and ResultsFrozen biopsies were obtained from a series of 51 breast cancers, which were either progressing primary tumours, local recurrences or contra-lateral breast lesions developed while patients received endocrine treatment. Hormonal treatment included aromatase inhibitors or tamoxifen, most of the patients reached post-menopausal age, miRNA profiles were obtained using Illumina DASL® Sentrix Array Matrix.Un-supervised hierarchical clustering split 51 studied endocrine resistant tumours into two major groups, distinctive in their miRNA profiles. Several of miRNAs discriminating between the clusters have already been implemented in breast cancer (mir7, mir10a, mir205, mir206, mir 210). Most of the other miRNAs associated with the main tumour clusters are yet to be studied in relation to breast cancer biology (e.g. mir192, mir625, mir941, mir145 and mir512 among others). The miRNA-based tumour clusters were not clearly associated with a specific treatment or type of resistance. The miRNAs most clearly able to discriminate between tumours resistant to AIs and Tamoxifen included mir186, mir196a, mir196b and miR-594:9.1 (p&lt;0.05, fold change &gt;1.2).DiscussionThe results show heterogeneity of miRNA profiles in endocrine resistant breast cancers, for the first time suggesting that endocrine resistant tumours can be split into two major molecular sub-groups basing on their miRNA profiles. The results suggest that (i) miRNA-mediated gene expression regulation may be involved in the mechanisms of endocrine resistance and (ii) miRNA profiling allows different molecular sub-classes of endocrine-resistant tumours to be distinguished.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 5130.

Gene Expression Profiles of Endocrine Resistant Breast Tumours

AimTo identify molecular sub-classes of endocrine-resistant breast tumours.MethodsWhole genome expression profiles of 55 endocrine-resistant tumours were obtained using Illumina HT-12 BeadChip arrays. Endocrine resistance was defined as either (i) tumour increased in size during hormonal treatment or (ii) appearance of local recurrence or (iii) contra-lateral breast lesion (metastases or new cancers) during hormonal treatment. Most of the treated patients were post-menopausal. Hormonal treatment included either aromatase inhibitors (letrozole, anastrazole, arimidex) or tamoxifen.ResultsUnsupervised hierarchical clustering using 500 most variable genes split tumours into three major clusters of approximately equal size. The genes discriminating between these clusters included oestrogen receptor- and proliferation- associated set of genes (ESR1, TFF1, TFF3, FOXA1, AGR2, AGR3, XBP1, GATA3, PRAD6B, MYB, CCND1), and stroma-related genes (DCN, COL1A1, COL1A2, COL3A1, COL5A2). Initial analysis of the studied tumours was unable to identify genes associated with clinical features. Sub-division of the dataset may be required to identify these genes more clearly. Genes that tended to separate between tumours resistant to AI and Tamoxifen included MYB, GPR137B, RNF19A, FRMD6, ZNF217 and RPS12. More detailed analysis of the data is underway.DiscussionUnderstanding and overcoming of endocrine resistance will improve treatment results for the majority of breast cancer patients. This abstract reports a new gene expression dataset to compare molecular features of biopsies collected from tumours growing while on endocrine treatment. The initial analysis demonstrates diversity of the resistance mechanisms, enhancing development of individual approaches to endocrine-resistant tumours.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 5132.

Role of CD38 in cell-cell interactions under conditions of endothelial dysfunction

We studied the role of receptor/ectoenzyme CD38 in the formation of endothelial damage and pathogenesis of endothelial dysfunction. CD38 was located in sites of protrusion of the outer cytoplasmic membrane. The majority of CD38+ accumulation sites coincided with the protrusion pole, while in some cells expression of CD38 was spread along the entire cell membrane surface or located on the pole opposite to the protrusion. We hypothesized that these states reflect the processes of rafting and clustering of the receptor, which are essential for cell-cell interactions in the pathogenesis of endothelial dysfunction.

Outcomes of conventional surgery and combined with endovascular intervention for acute thromboses of atherosclerotically arteries comparative study

The study was aimed at early outcome retrospective analysis of conventional surgery (CS) for acute arterial obstruction (AAO) of lower limb arteries with atherosclerotic lesions and of simultaneous combined treatment (SCT) - endovascular intervention undertaken during open surgery.

MATERIALS AND METHODS

166 histories of patients with AAO and atherosclerotic lesions of lower limb arteries, treated during 1998-2005. Conventional surgical therapy was used in 72 cases and comprised open and indirect thrombectomy with endarterectomy and/or femoral arterioplasty if indicated. In 94 eases open surgery was combined with pre- or intraoperative angiography and endovascular balloon angioplasty.

RESULTS

restoration of blood flow during primary intervention was achieved in 58.3% of patients after CS and in 72.3% of patients after SCT; the rate of amputations was 31.9% and 18.1%, respectively, mortality - 16.6% and 6.3%, respectively, favorable outcome at the discharge - 62.5% and 79.9%.

CONCLUSION

endovascular angioplasty of atherosclerotic stenoses during open surgery for acute thromboses of lower limb arteries has distinct benefits over conventional surgical treatment.

Aromatase inhibitors: cellular and molecular effects

Marked cellular and molecular changes may occur in breast cancers following treatment of postmenopausal breast cancer patients with aromatase inhibitors. Neoadjuvant protocols, in which treatment is given with the primary tumour still within the breast, are particularly illuminating. In Edinburgh, we have shown that 3 months treatment with either anastrozole, exemestane or letrozole produces pathological responses in the majority of oestrogen receptor (ER)-rich tumours (39/59) as manifested by reduced cellularity/increased fibrosis. Changes in histological grading may also take place, most notably a reduction in mitotic figures. This probably reflects an influence on proliferation as most tumours (82%) show a marked decrease in the proliferation marker, Ki67. These effects are generally more dramatic than seen with tamoxifen given in the same setting. Differences between aromatase inhibitors and tamoxifen are also apparent in changes in steroid hormone expression. Thus, immuno-staining for progesterone receptor (PgR) is reduced in almost all cases by aromatase inhibitors, becoming undetectable in many. This contrasts with effects of tamoxifen in which the most common change on PgR is to increase expression. Changes in proliferation occur rapidly following the onset of exposure to aromatase inhibitors. Thus, neoadjuvant studies with letrozole in which tumour was sampled before and after 14 days and 3 months treatment show that decreased expression of Ki67 occur at 14 days and, in many cases, the effect is greater at 14 days than 3 months. These early changes precede evidence of clinical response but do not predict for it. However, this study design has allowed RNA analysis of sequential biopsies taken during the neoadjuvant therapy. Based on clustering techniques, it has been possible to subdivide tumours into groups showing distinct patterns of molecular changes. These changes in tumour gene expression may allow definition of tumour cohorts with differing sensitivity to aromatase inhibitors and permit early recognition of response and resistance.

[Esophagoplasty with the colon in flap patients with burn strictures of the esophagus]

Results of coloesophagoplasty in 366 patients with long burn strictures of the esophagus are presented. The lesion was total in 74 (21.2%) of them. Inefficacy of bougieurage was indication for plastic surgery in 133 (36.3%) patients, complete obliteration of esophagus--in 53 (14.5%). Left half of the colon was used in 296 (80.9%) cases, transverse colon--in 48 (13.1%), right half of the colon--in 22 (6.0%) cases. Retrosternal shunting esophagoplasty was performed in 247 (67.5%) patients. Complications were in 84 (34.0%), necrosis of the transplant--in 4 (1.6%) patients. Extirpation of the esophagus with posteriormediastinoplasty was performed in 16 (4.4%) patients, in 14 of them--transhiatally. Complications occurred in 7 patients coloesophagopharyngoplasty was carried out in 52 (14.2%) patients with combined stricture of the esophagus and the pharynx, in 23 of them--simultaneously. Complications were in 28 (53.8%) patients. Intrapleural of coloesophagoplasty was performed in 51 patients. General hospital lethality was 3.3%. Long-term results were studied in 259 patients. Good results of esophagoplasty were seen in 135 (52.1%) patients, satisfactory--in 65 (25.1%), unsatisfactory--in 59 (22.8%) patients. Dysfunction of the artificial esophagus was seen in 22.0% patients, 12.7% patients underwent repeated reconstructive surgeries.

Aromatase in skeletal muscle

Aromatase gene expression and activity have been studied in human skeletal muscle. Using two separate rounds of RT-nested PCR, transcripts from the coding region of aromatase mRNA were detected in 32 of 34 samples. In terms of the non-coding exon I, PCR product for I.4 was detected in 13 cases (38%), I.3 in 10 cases (29%), P.II in 6 cases (18%) and I.1 was not detected in any case. No transcripts for any studied variants of exon I were detected in 18 samples (53%). Aromatase activity was assessed using two different methodologies: in 19 cases by definitive product isolation (DPI) and in 42 cases by tritium-release assay (TRA). Using both methods detectable activity was present in 52% of cases. Average values for the cases with detectable activity were 2.2 fmol/mg protein/h for DPI and 6.5 fmol/mg protein/h for TRA. In the cohort studied by TRA, a positive correlation of aromatase activity with age of the donor was observed (r=0.34, P=0.03). In six cases paired comparison of aromatase activity in muscle and associated fat tissue were performed by DPI. When expressed per milligram of protein the activity was always higher in fat. However, this difference disappeared when activity was based on the gram of wet tissue. Taking into account bulk in the body it is concluded that muscle can be an important source of estrogens in men and post-menopausal women and its contribution to the circulating pool of estrogens may be comparable to that of adipose tissue. The nature of mRNA transcripts in muscle suggests that estrogen formation may be controlled by glucocorticoid- as well as cAMP-dependent promoters of the aromatase gene.

Fine structure of excitons in InAs/GaAs coupled auantum dots: a sensitive test of electronic coupling

Exciton fine structure in InAs/GaAs coupled quantum dots has been studied by photoluminescence spectroscopy in magnetic fields up to 8 T. Pronounced anticrossings and mixings of optically bright and dark states as functions of magnetic field are seen. A theoretical treatment of the mixing of the excitonic states has been developed, and it traces observed features to structural asymmetries. These results provide direct evidence for coherent coupling of excitons in quantum dot molecules.

Local uptake and synthesis of oestrone in normal and malignant postmenopausal breast tissues

Uptake and local formation of oestrone (E1) were studied in vivo by a double isotopic technique in normal and malignant breast tissues from 24 postmenopausal women with breast cancer. Active uptake of radio-labelled E1 beyond plasma was found both in normal and malignant tissue, the effect being significantly greater in non-malignant compared with cancer tissue. The presence of local E1 formation was also demonstrated in most samples. Both uptake and synthesis positively correlated with total amount of radioactive E1 found in the tissues. Uptake appeared to make a greater contribution to E1 levels within the breast than in situ synthesis, although there were marked variations between specimens from different patients and the relative proportion of synthesis to uptake was higher in tumour compared with non-malignant tissue. These results demonstrate quantitative differences in the different compartments by which postmenopausal breasts obtain oestrogen and highlight variations between individual breasts. This may be important in optimising oestrogen deprivation therapy for postmenopausal patients with hormone-dependent cancers.

Aromatase (CYP19) expression in tumor-infiltrating lymphocytes and blood mononuclears

PURPOSE

To clarify the role of lymphocytes as a possible source of estrogens.

METHODS

In the present study, lymphocytes were isolated from 11 surgical samples of breast cancer after tumor enzyme digestion and Ficoll/Verographine procedure. Simultaneously, using the latter procedure, mononuclears were separated from the blood of 15 female volunteers.

RESULTS

Expression of the aromatase (CYP19) gene was readily demonstrated by standard RT-PCR in blood mononuclears cultivated in the presence of 10% fetal calf serum for 48 h. In the tumor-infiltrating lymphocytes (TIL) of breast cancer patients, CYP19 expression was discovered only with the aid of nested PCR.

CONCLUSIONS

The data obtained suggest that aromatase gene expression is presented in TIL at a rather low level. Nevertheless, this can have some functional significance for the estrogen-dependent growth of breast cancer tissue.

[Neoadjuvant use of the aromatase inhibitor letrozole in uterine cancer: endocrine and clinical effects]

Endometrial cancer (EC) is estrogen-dependent tumor in the hormonal treatment of which mostly progestins are used. During last 5-7 years feasibility of aromatase inhibitors use in EC is discussed without any special practical move in this direction. To evaluate possible biological response of tumor and patients to such treatment, we conducted a short pilot study involving 10 primary postmenopausal EC patients, mostly stage Ia,b (average age 59) who received letrozole (Femara, Novartis) 2.5 mg/day during 14 days before operation. Clinical, sonographical, morphological, cytological and hormonal-metabolic (blood estradiol, FSH, LH, glucose, lipid fractions by RIA or enzyme-colorimetric methods; tumor progesterone receptors by LBA and aromatase activity by 3H-water release assay) studies were included into the protocol before and after treatment. Tolerability of letrozole was satisfactory in all patients. 2 patients reported decrease of pain and pathological secretions from uterine cavity. In 3 patients, decrease in M-sonographical endometrial signal was registered; average value after treatment was 31.1% lower than before it. Tendency to the decrease in estrogenicity of vaginal smears was revealed. Average decrease in blood estradiol was 37.8% and in progesterone receptor level and aromatase activity 34.4% and 17.5% respectively. Decrease of aromatase activity in tumor tissue was registered mostly in normal weight patients. A more detailed and longer randomized study of aromatase inhibitors in EC performed in neoadjuvant setting deserves consideration.

Inhibition and enhancement of the spontaneous emission of quantum dots in structured microresonators

Spontaneous emission of quantum dot systems in laterally structured microcavities that exhibit photon confinement in all three directions has been studied by time-resolved photoluminescence spectroscopy. For on-resonance conditions, we find that the dot emission rate is increased substantially over that of the unstructured planar cavity. For off-resonance conditions, we are able to suppress the emission rate by an order of magnitude by using cavities with metal coatings, which we attribute to the suppression of leaky optical modes in these structures.

[Aromatase gene expression and its modifying factors in breast tumor tissue]

Aromatase (CYP 19) gene expression was studied in 70 breast tumors. When RNA-dot-blot or rt-polymerase chain reaction were used expression frequency was 60.4 and 91.7%, respectively. An analysis of individual variants of non-coding exon of aromatase gene confirmed that, unlike normal mammary tissue, tumor switched from activation of exon I.4 ("sensitive" to glucocorticoids) to exons II ("sensitive" to cAMP) or I.3. This difference was relatively somewhat more pronounced in the Russian material. Direct correlation between aromatase enzymatic activity and expression of exons II and I.3 in tumor tissue appeared more significant than that of aromatase gene coding site. An evaluation of the expression of adenylate cyclase G-protein alpha-subunit genes established an inverse correlation between expression of Gi2a and exon I.3. Breast tumors with elevated basal aromatase activity were more sensitive to aromatase inhibitors (letrozole, 4-OHA) in vitro although no relationship between use of CYP19 (aromatase) 5' exon variant and in vitro inhibition of aromatase was detected. A correlation was observed between expression of aromatase gene and variants of its 5' exon, on the one hand, and age, tumor grade, steroid receptor presence and tumor lymphocytic infiltration, on the other. To summarize, local estrogen production in breast tumor tissue is regulated by a wide range of factors expression both aromatase gene influencing and its enzymatic activity, thus providing leverage on both.

[Aromatase (estrogen synthetase) gene expression in human leukocytes]

Extragonadal aromatization plays an important role in many physiological and pathological conditions. It has been found that incubation of the peripheral blood mononuclears in the RPMI-1640 medium with 10% fetal calf serum during 48 hrs is able to induce the aromatase gene expression. The latter did not occur in 11 samples of mononuclears of the intra-tissue leukocyte infiltration which finding needs further investigation. The data obtained suggest that the possibility of the aromatase gene induction in leukocytes is associated with the cellular fraction capable of the substrate adhesion.

[Aromatase activity and its gene expression in tumor tissue of smokers and non-smokers with breast cancer]

Tissue was sampled from 121 tumors of the breast. The activity of aromatase (estrogen synthetase) was assessed by radiobiochemical means in 61 cases; gene expression was evaluated with the aid of polymerase chain reaction in 14 and the same--by the dot-blot procedure in 46 patients. Inveterate smokers (15 years and more) made up 16.5%. The smokers revealed a distinct tendency towards aromatase activity decreasing in tumor tissue (chiefly in menopausal patients) as well as lower intensity of aromatase gene expression assessed in terms of polymerase chain reaction. Alongside with other evidence, our finding point to long-term-smoking-related sensitivity of intratissular estrogen synthesis being higher than in general circulation. It also demonstrated local aromatization inhibition in tumor tissue, the latter being a possible mechanism which causes tumor tissue hormone sensitivity to change in smokers and affects course of disease.

[Distraction osteosynthesis in occlusive diseases of the limb arteries]

The method of distraction osteosynthesis was used in 265 patients with arterial occlusions of the upper and lower limbs, which developed due to obliterative thromboangiitis and atherosclerosis. Surgical treatment of patients with distal type of occlusive disease of the arteries was followed by steady compensation of ischemic disturbances after bone chip formation and its dosage across transfer with formation of distraction regenerate transforming into mature osseous tissue. Favourable results of the treatment were observed in 236 patients (88.9%). They persisted during 3 years in 86% of patients. Analysis of outcomes after treatment demonstrated the best results in patients with grade II ischemia. Distraction osteosynthesis ensured protracted remission of the disease and elimination of its symptoms.

[Metabolism of the androgenic precursor androstenedione and effects of aromatase inhibitors in cultured blood lymphocytes]

Blood lymphocytes from 26 women were cultivated in RPMI-1640 for 72 hrs with or without dexamethasone, dbcAMP, and TPA. Androstenedione conversion was most often activated by the dbcAMP, then by Dex and TPA. Response to dbcAMP was most obvious in women under 50, whereas response to Dex--in women over 50. Aromatase inhibitor fadrosol displayed a tendency towards prevention of the activation of androstenedione conversion in cultivated lymphocytes. A possibility of aromatase gene induction in cultivated lymphocytes cannot be completely excluded and demands further investigation with the aid of molecular-genetic methods.

Ability of lymphocytes infiltrating breast-cancer tissue to convert androstenedione

Lymphocytes were isolated from 43 surgical samples of breast cancer after tumor enzyme digestion and Ficoll/Verographine procedure. In all, 23 specimens from lymphocytic-tissue infiltrates were analyzed (in some cases, material from 2 or 3 patients was combined). The ability of tumor-infiltrating lymphocytes (TIL) to convert androstenedione was demonstrated, as evaluated by hard-water release from the androgenic precursor 3H-1beta-androstenedione. In material obtained from menopausal women this ability was higher than in the women of reproductive age. A positive correlation was revealed between the level of androstenedione conversion in TIL and aromatase activity in tumor tissue, while no correlation was shown between androstenedione conversion in TIL and percentage of tumor cells in lymphocytic suspension. The data obtained suggest that factors secreted by a neoplasm are able to induce aromatase gene expression in TIL.

[Correlation between tumor tissue aromatase, histological pattern and reproductive status in patients with breast cancer]

Aromatase levels were measured in tumor tissue vis-a-vis clinico-morphological patterns of tumor, menopausal status and sex hormone concentration in blood in 50 patients with breast tumors. The test was based on heavy water release from 1 beta-3H-androstenedione. Direct correlation was established between aromatase concentration, on the one hand, and tumor size, cell differentiation status and blood-testosterone on the other. The data point to the role of aromatase concentration in situ during breast tumor genesis, its dependence on hormonal environment of tumor and its presence in breast tumor cells.

Aromatase in breast cancer tissue--localization and relationship with reproductive status of patients

The precise place of local estrogen production in mammary cancer is still controversial. In this investigation localization of aromatase (the key enzyme of estrogen biosynthesis) was studied in breast cancer tissue by immunohistochemical method using polyclonal rabbit antibodies. The cytoplasmic staining was found in different cell types, but the most intensive specific staining was found in malignant cells and it was stronger (P < 0.01) in postmenopausal patients than in patients of reproductive age.

[Aromatase activity in human muscle tissue]

Activity of aromatase (estrogen synthetase) was investigated in muscle tissue of 14 women and 2 men. The method of hard water release from androgenic precursor 3H-beta-androstendione was used. In men aromatase activity in muscle tissue is lower than women. For the latter group the enzyme activity is highest after 5-10 year of menopause and in the case of increased body fat content. In the future it looks interesting to correlate muscle tissue aromatase activity level with blood estrogens concentration, prevailing type of muscle fibers and physical activity rate of probands.

[Correlation of lymphocytic infiltration of tumor tissue with the hormonal and metabolic state in patients with breast cancer]

Lymphocyte infiltration of tumor was studied vis-a-vis hormone metabolic status, tumor tissue hormone sensitivity and tobacco smoking, in 113 breast cancer patients, aged 25-77. On the average, no correlation was established between degree of lymphocyte infiltration in breast tumor and age and menopause onset. In smoking menopausal patients, lymphocyte infiltration was found to be higher than in non-smokers (p < 0.05). There was a direct correlation between the rate of lymphocyte infiltration and the level of progesterone receptors in tumor. Some subgroups displayed a direct correlation between infiltration and sex-binding globulin, cholesterol, luteinizing hormone in blood, and lean body mass. It was matched by an inverse correlation between lymphocyte infiltration and blood-thyroid hormone concentration, urine catecholamines and free cortisol excretion and fat/lean body mass ratio. Considering the abovesaid as well as the lymphocyte ability to perform the dual function of immunocytes and hormonocytes, it is suggested that the results may be used in both the study of lymphocyte infiltration and research in means of its control.