Functional network structure supports resilience to memory deficits in cognitively normal older adults with amyloid-β pathology

Older adults may harbor large amounts of amyloid-β (Aβ) pathology, yet still perform at age-normal levels on memory assessments. We tested whether functional brain networks confer resilience or compensatory mechanisms to support memory in the face of Aβ pathology. Sixty-five cognitively normal older adults received high-resolution resting state fMRI to assess functional networks, 18F-florbetapir-PET to measure Aβ, and a memory assessment. We characterized functional networks with graph metrics of local efficiency (information transfer), modularity (specialization of functional modules), and small worldness (balance of integration and segregation). There was no difference in functional network measures between older adults with high Aβ (Aβ+) compared to those with no/low Aβ (Aβ-). However, in Aβ+ older adults, increased local efficiency, modularity, and small worldness were associated with better memory performance, while this relationship did not occur Aβ- older adults. Further, the association between increased local efficiency and better memory performance in Aβ+ older adults was localized to local efficiency of the default mode network and hippocampus, regions vulnerable to Aβ and involved in memory processing. Our results suggest functional networks with modular and efficient structures are associated with resilience to Aβ pathology, providing a functional target for intervention.

Glycogen synthase 1 targeting reveals a metabolic vulnerability in triple-negative breast cancer

BACKGROUND

Hypoxia-induced glycogen turnover is implicated in cancer proliferation and therapy resistance. Triple-negative breast cancers (TNBCs), characterized by a hypoxic tumor microenvironment, respond poorly to therapy. We studied the expression of glycogen synthase 1 (GYS1), the key regulator of glycogenesis, and other glycogen-related enzymes in primary tumors of patients with breast cancer and evaluated the impact of GYS1 downregulation in preclinical models.

METHODS

mRNA expression of GYS1 and other glycogen-related enzymes in primary breast tumors and the correlation with patient survival were studied in the METABRIC dataset (n = 1904). Immunohistochemical staining of GYS1 and glycogen was performed on a tissue microarray of primary breast cancers (n = 337). In four breast cancer cell lines and a mouse xenograft model of triple-negative breast cancer, GYS1 was downregulated using small-interfering or stably expressed short-hairpin RNAs to study the effect of downregulation on breast cancer cell proliferation, glycogen content and sensitivity to various metabolically targeted drugs.

RESULTS

High GYS1 mRNA expression was associated with poor patient overall survival (HR 1.20, P = 0.009), especially in the TNBC subgroup (HR 1.52, P = 0.014). Immunohistochemical GYS1 expression in primary breast tumors was highest in TNBCs (median H-score 80, IQR 53-121) and other Ki67-high tumors (median H-score 85, IQR 57-124) (P < 0.0001). Knockdown of GYS1 impaired proliferation of breast cancer cells, depleted glycogen stores and delayed growth of MDA-MB-231 xenografts. Knockdown of GYS1 made breast cancer cells more vulnerable to inhibition of mitochondrial proteostasis.

CONCLUSIONS

Our findings highlight GYS1 as potential therapeutic target in breast cancer, especially in TNBC and other highly proliferative subsets.

Radiogenomic analysis of primary breast cancer reveals [18F]-fluorodeoxglucose dynamic flux-constants are positively associated with immune pathways and outperform static uptake measures in associating with glucose metabolism

BACKGROUND

PET imaging of 18F-fluorodeoxygucose (FDG) is used widely for tumour staging and assessment of treatment response, but the biology associated with FDG uptake is still not fully elucidated. We therefore carried out gene set enrichment analyses (GSEA) of RNA sequencing data to find KEGG pathways associated with FDG uptake in primary breast cancers.

METHODS

Pre-treatment data were analysed from a window-of-opportunity study in which 30 patients underwent static and dynamic FDG-PET and tumour biopsy. Kinetic models were fitted to dynamic images, and GSEA was performed for enrichment scores reflecting Pearson and Spearman coefficients of correlations between gene expression and imaging.

RESULTS

A total of 38 pathways were associated with kinetic model flux-constants or static measures of FDG uptake, all positively. The associated pathways included glycolysis/gluconeogenesis ('GLYC-GLUC') which mediates FDG uptake and was associated with model flux-constants but not with static uptake measures, and 28 pathways related to immune-response or inflammation. More pathways, 32, were associated with the flux-constant K of the simple Patlak model than with any other imaging index. Numbers of pathways categorised as being associated with individual micro-parameters of the kinetic models were substantially fewer than numbers associated with flux-constants, and lay around levels expected by chance.

CONCLUSIONS

In pre-treatment images GLYC-GLUC was associated with FDG kinetic flux-constants including Patlak K, but not with static uptake measures. Immune-related pathways were associated with flux-constants and static uptake. Patlak K was associated with more pathways than were the flux-constants of more complex kinetic models. On the basis of these results Patlak analysis of dynamic FDG-PET scans is advantageous, compared to other kinetic analyses or static imaging, in studies seeking to infer tumour-to-tumour differences in biology from differences in imaging. Trial registration NCT01266486, December 24th 2010.

Characterising 18F-fluciclovine uptake in breast cancer through the use of dynamic PET/CT imaging

BACKGROUND

18F-fluciclovine is a synthetic amino acid positron emission tomography (PET) radiotracer that is approved for use in prostate cancer. In this clinical study, we characterised the kinetic model best describing the uptake of 18F-fluciclovine in breast cancer and assessed differences in tracer kinetics and static parameters for different breast cancer receptor subtypes and tumour grades.

METHODS

Thirty-nine patients with pathologically proven breast cancer underwent 20-min dynamic PET/computed tomography imaging following the administration of 18F-fluciclovine. Uptake into primary breast tumours was evaluated using one- and two-tissue reversible compartmental kinetic models and static parameters.

RESULTS

A reversible one-tissue compartment model was shown to best describe tracer uptake in breast cancer. No significant differences were seen in kinetic or static parameters for different tumour receptor subtypes or grades. Kinetic and static parameters showed a good correlation.

CONCLUSIONS

18F-fluciclovine has potential in the imaging of primary breast cancer, but kinetic analysis may not have additional value over static measures of tracer uptake.

CLINICAL TRIAL REGISTRATION

NCT03036943.

Male factor infertility and placental pathology in singleton live births conceived with in vitro fertilization

PURPOSE

We sought to determine whether pregnancies conceived in those with male factor infertility have unique placental pathology profiles compared to those undergoing infertility treatments for other indications.

METHODS

This was a retrospective cohort study of placental pathology from 464 live births conceived from autologous fresh IVF cycles at an academic fertility center from 2004 to 2017. Placental pathology was compared between live births arising from patients with male factor infertility alone and those with another infertility diagnosis. Placental outcomes were compared with parametric or non-parametric tests; logistic regression was performed to account for potential confounders.

RESULTS

Compared to cycles performed for a non-male factor diagnosis, male factor infertility cycles had a higher mean paternal age (38.2 years vs. 36.5 years, p < 0.001), a higher female mean BMI (24.3 vs. 23.3 kg/m2, p = 0.01), and a lower day 3 follicle stimulating hormone (FSH) level (6.8 vs. 7.3 IU/mL, p = 0.02). The mean numbers of embryos transferred, and day of transfer were similar between groups, and more cycles used ICSI in the male factor infertility group (90.6% vs. 22.5%, p < 0.001). Placental pathology in our adjusted model was similar between the male factor and non-male factor groups. In our unadjusted subgroup analysis, cycles for male factor using ICSI appeared to lead to more small placentas by weight compared to cycles performed with conventional insemination (45.8% < 10th percentile vs. 18.8%, p = 0.04).

CONCLUSION

Male factor infertility is not associated with significantly different placental pathology compared to other infertility diagnoses.

Abstract P4-08-17: Expression score (Escore) for the prediction of likelihood of recurrence of DCIS

Background: Ductal carcinoma in situ (DCIS) accounts for at least 20% of breast cancers. Factors associated with recurrence of DCIS or progression to invasive carcinoma are not well delineated. The goals of the current study were to profile the epithelial cells using the GE Cell DIVE™ immuno-fluorescent based analyses. This was coupled with semi-automated algorithms to characterize the inter-relationships between cell populations and likelihood of recurrence.

Patients and Methods: A TMA-based (total 8 TMAs) cohort of cases of DCIS with and without recurrence was obtained from Oxford University. Recurrence in this cohort was defined as ipsilateral DCIS, ipsilateral invasive, contralateral invasive and metastatic. Analysis for 31 epithelial markers (HER4, CK56, ABCG2, PTEN, S6, CKAE1, PR, ER, NaKATPase, CK19, ALDH1, CK PCK26, cMET, CD44v6, HER2, CDCP1, p53, CK15, COX2, VEGFR2, ABCb1, HTF9C, CD10, MRP4, CEACAM5, EGFR, p21, MRP5, SLC7A5, Ki67, DAPI) was performed on a single FFPE TMA section containing cases of DCIS. Briefly, FFPE sections from TMAs containing DCIS were sequentially (cyclically) stained for the markers. Each cycle entailed staining with 2-3 markers followed by imaging, dye inactivation, and re-staining. DAPI was used for nuclear demarcation and for registration of the images, while S6, pan-cadherin, Na+K+ATPase and pan-cytokeratin were used for epithelial segmentation. K-means clustering followed regression analysis was performed to identify inter-relationships between markers and association with likelihood of recurrence. Log-rank analysis was performed and the relapse-free survival data depicted using Kaplan Meier plots. Escore was developed by logistic regression model, classification model on recurrence

Results: Filtering of the expression analysis by the quality, specificity, compartment localization and fields entirely composed of DCIS, in addition to availability of clinical data resulted final analysis of 31 markers in 67 cases. Correlation analyses were performed on each of the markers to identify markers that were significantly correlated in univariate analysis. K-means cluster analysis was performed using a set of 4 markers (ER, HER2, SLC7A5 and cMET) to identify 6 clusters. High cMET (cluster 1; low HER2 and SLC7A5) and High ER (low cMET, HER2, SLC7A5; Cluster 5) were associated with low risk of recurrence (p values 0.014 and &lt;0.0001). In contrast, Cluster 2 (High HER2, high SLC7A5, low ER) and Cluster 3 (High HER2, low ER, SLC7A5and cMET) were associated with increased risk of recurrence (P values 0.038 and 0.076). A regression analysis based algorithm was developed using these markers to calculate a numerical score which could predict likelihood of recurrence. As depicted in the KM plots, the HR for recurrence increases significantly (P-value 2.4E-05; p=0.02 with LOOCV) with increase in expression score (Escore).

Conclusions: We describe the development of an Escore using expression 4 markers to predict likelihood of recurrence. Additional ongoing studies will seek to validate the utility of the Escore in predicting likelihood of recurrence of DCIS and development of invasive carcinomas and comparison with other scoring systems.

Citation Format: Badve SS, Cho S, Gokmen-Polar Y, Zavodszky M, Sui Y, Chadwick C, Tan PH, Gerdes M, Harris AL, Ginty F. Expression score (Escore) for the prediction of likelihood of recurrence of DCIS [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 P4-08-17.

Antiangiogenic and tumour inhibitory effects of downregulating tumour endothelial FABP4

Fatty acid binding protein 4 (FABP4) is a fatty acid chaperone, which is induced during adipocyte differentiation. Previously we have shown that FABP4 in endothelial cells is induced by the NOTCH1 signalling pathway, the latter of which is involved in mechanisms of resistance to antiangiogenic tumour therapy. Here, we investigated the role of FABP4 in endothelial fatty acid metabolism and tumour angiogenesis. We analysed the effect of transient FABP4 knockdown in human umbilical vein endothelial cells on fatty acid metabolism, viability and angiogenesis. Through therapeutic delivery of siRNA targeting mouse FABP4, we investigated the effect of endothelial FABP4 knockdown on tumour growth and blood vessel formation. In vitro, siRNA-mediated FABP4 knockdown in endothelial cells led to a marked increase of endothelial fatty acid oxidation, an increase of reactive oxygen species and decreased angiogenesis. In vivo, we found that increased NOTCH1 signalling in tumour xenografts led to increased expression of endothelial FABP4 that decreased when NOTCH1 and VEGFA inhibitors were used in combination. Angiogenesis, growth and metastasis in ovarian tumour xenografts were markedly inhibited by therapeutic siRNA delivery targeting mouse endothelial FABP4. Therapeutic targeting of endothelial FABP4 by siRNA in vivo has antiangiogenic and antitumour effects with minimal toxicity and should be investigated further.

Abstract P1-06-02: Impact of heterogeneity of DCIS on immune cell infiltrations

Background: Ductal carcinoma in situ (DCIS) accounts for at least 20% of breast cancers. Factors associated with recurrence of DCIS or progression to invasive carcinoma are not well delineated. The goals of the current study were to profile the epithelial and immune cells using the MultiOmyx hyperplexed immuno-fluorescent based analyses. This was coupled with semi-automated algorithms to characterize the inter-relationships between cell populations within individual DCIS lesions.

Patients and Methods: Analysis for 15 antibody markers (EGFR, Her2, Her4, S6, pMTOR, PCAD, CD44v6, NaKATPase, SLC7A5, CD4, CD8, CD20, CD68, and CD10) was performed on a single FFPE section containing 10-20 distinct ducts from 13 cases of DCIS. Briefly, approximately 40 fields of view (FOV) from digitized sections containing DCIS or normal tissue were sequentially (cyclically) stained for the 15 markers. Each cycle entailed staining with 2-3 markers followed by imaging, dye inactivation, and re-staining. DAPI was used for nuclear demarcation and for registration of the images, while S6, pan-cadherin, Na+K+ATPase and pan-cytokeratin were used for epithelial segmentation. K-means clustering was used to determine patterns of co-expression of markers at the single cell, duct, and patient levels. These clusters were then correlated with immune marker expression by tumor infiltrating lymphocytes (TILs) by marker type (CD4, CD8, and CD20) and tumor compartment (stromal versus intraepithelial).

Results: Analysis of the epithelial component in each of 13 cases of DCIS (n= 415 ducts) revealed 8 distinct expression patterns (clusters) using a panel of 7 markers (EGFR, Her2, Her4, pmTOR, CD44v6, SLC7A5, and CD10). The frequency and distribution of clusters, annotated at the single cell level, showed that 4 DCIS's were dominated (&gt;80%) by a single cell phenotype represented by cluster groups 3 and 7 (high Her2), cluster 6 (High Her4 and SLC7A5 and low Her2), or cluster 4 (non-descript). In 5 pts, the pattern was more heterogeneous consisting of mixture of cell populations with 50-70% of the cells belonging to cluster 1 (moderate to high levels for all markers except EGFR and CD10). The remaining pts had a strong representation of cluster 4 and 5 (CD44v6 and phospho-mTOR) cells. The distribution of both intra-epithelial and stromal TILs in DCIS cases were either consisted of a mixed B-cell (CD20+) and T-cell response (n=4), or one dominated by T-cells. Cluster 2 (High EGFR and CD10) was associated with a largely T-cell response (rs = 0.83, P value = 0.0004), while Cluster 7 (strong HER2) was associated with a B-cell response (rs = 0.68, P value = is 0.009).

Conclusions: Analysis 15 markers and use of K-means clustering algorithm, shows prominent inter-tumoral (but not intra-tumoral) heterogeneity in DCIS. Furthermore, epithelial cell specific clusters (high HER2 or EGFR) were associated with distinct B or T cell infiltration by TILs. Additional ongoing studies will determine the clinical significance of the clusters with respect to recurrence of DCIS and development of invasive carcinomas.

Citation Format: Badve S, Gökmen-Polar Y, Harris AL, Sui Y, Sevinsky C, Santamaria-Pang A, Ginty F, Tan PH, Gerdes MJ. Impact of heterogeneity of DCIS on immune cell infiltrations [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 P1-06-02.

The BET inhibitor JQ1 selectively impairs tumour response to hypoxia and downregulates CA9 and angiogenesis in triple negative breast cancer

The availability of bromodomain and extra-terminal inhibitors (BETi) has enabled translational epigenetic studies in cancer. BET proteins regulate transcription by selectively recognizing acetylated lysine residues on chromatin. BETi compete with this process leading to both downregulation and upregulation of gene expression. Hypoxia enables progression of triple negative breast cancer (TNBC), the most aggressive form of breast cancer, partly by driving metabolic adaptation, angiogenesis and metastasis through upregulation of hypoxia-regulated genes (for example, carbonic anhydrase 9 (CA9) and vascular endothelial growth factor A (VEGF-A). Responses to hypoxia can be mediated epigenetically, thus we investigated whether BETi JQ1 could impair the TNBC response induced by hypoxia and exert anti-tumour effects. JQ1 significantly modulated 44% of hypoxia-induced genes, of which two-thirds were downregulated including CA9 and VEGF-A. JQ1 prevented HIF binding to the hypoxia response element in CA9 promoter, but did not alter HIF expression or activity, suggesting some HIF targets are BET-dependent. JQ1 reduced TNBC growth in vitro and in vivo and inhibited xenograft vascularization. These findings identify that BETi dually targets angiogenesis and the hypoxic response, an effective combination at reducing tumour growth in preclinical studies.

Sentinel lymph node surgery after neoadjuvant chemotherapy in patients with T2 to T4, N0 and N1 breast cancer

BACKGROUND

Histological status of axillary lymph nodes is an important prognostic factor in patients receiving surgery for breast cancer (BC). Sentinel lymph node (SLN) biopsy (B) has rapidly replaced axillary lymph node dissection (ALND), and is now the standard of care for axillary staging in patients with clinically node-negative (N0) operable BC. The aim of this study is to compare pretreatment lymphoscintigraphy with a post primary systemic treatment (PST) scan in order to reduce the false-negative rates for SLNB.

METHODS

In this single-institution study we considered 170 consecutive T2-4 N0-1 M0 BC patients treated with anthracycline-based PST. At the time of incisional biopsy, we performed sentinel lymphatic mapping. After PST, all patients repeated lymphoscintigraphy with the same methodology. During definitive surgery we performed further sentinel lymphatic mapping, SLNB and ALND.

RESULTS

The SLN was removed in 158/170 patients giving an identification rate of 92.9% (95% confidence interval (CI) = 88.0-96.3%) and a false-negative rate of 14.0% (95% CI = 6.3-25.8%). SLNB revealed a sensitivity of 86.0% (95% CI = 74.2-93.7%), an accuracy of 94.9% (95% CI = 90.3-97.8%) and a negative predictive value of 92.7% (95% CI = 86.1-96.8%).

CONCLUSION

Identification rate, sensitivity and accuracy are in accordance with other studies on SLNB after PST, even after clinically negative node conversion following PST. This study confirms that diagnostic biopsy and neoadjuvant chemotherapy maintain breast lymphatic drainage unaltered.

Expression of miR-210 in relation to other measures of hypoxia and prediction of benefit from hypoxia modification in patients with bladder cancer

BACKGROUND

The addition of hypoxia modifiers carbogen and nicotinamide (CON) to radiotherapy (RT) improved overall survival (OS) in bladder cancer patients in the BCON phase III clinical trial. We investigate whether expression of hsa-miR-210 in BCON patient samples reflects hypoxia and predicts benefit from hypoxia modification.

METHODS

In all, 183 T1-T4a bladder cancer samples were available for miR-210 analysis. A total of 86 received RT+CON and 97 received RT alone. TaqMan qPCR plates were used to assess miR-210 expression. Patients were classified as low (

RESULTS

Patients with high miR-210 had a trend towards improved 5-year OS with RT+CON (53.2%) compared with RT alone (37.8%; hazard ratio (HR) 1.68, 95% CI 0.95-2.95, P=0.07). No benefit was seen with low miR-210 (HR 1.02, 95% CI 0.58-1.79, P=0.97). High miR-210 was significantly associated with high HIF-1α protein (P=0.001), CA9 protein (P=0.0004), Glut-1 protein (P=0.001), 26-gene hypoxia score (P=0.007), tumour necrosis (P=0.02) and concurrent pTis (P=0.03).

CONCLUSIONS

High miR-210 may reflect hypoxia in bladder cancer. However, its ability to predict benefit from hypoxia modification does not improve upon other hypoxia markers. Investigation as part of a miRNA hypoxia signature may reveal the full potential of miR-210.

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Key Words

• bladder cancer
• microrna
• hypoxic modification
• necrosis
• biomarker
• radiotherapy
• carbogen and nicotinamide

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MESH Headings

• Aged
• Aged, 80 and over
• Cell Hypoxia/genetics
• Female
• Humans
• Male
• MicroRNAs/genetics
• Middle Aged
• Urinary Bladder Neoplasms/genetics
• Urinary Bladder Neoplasms/pathology

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Grants

• 11359 Cancer Research UK
• G0300648 Medical Research Council
• 16466 Cancer Research UK
• G0801525 Medical Research Council
• 18974 Cancer Research UK

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PAT4 levels control amino-acid sensitivity of rapamycin-resistant mTORC1 from the Golgi and affect clinical outcome in colorectal cancer

Tumour cells can use strategies that make them resistant to nutrient deprivation to outcompete their neighbours. A key integrator of the cell's responses to starvation and other stresses is amino-acid-dependent mechanistic target of rapamycin complex 1 (mTORC1). Activation of mTORC1 on late endosomes and lysosomes is facilitated by amino-acid transporters within the solute-linked carrier 36 (SLC36) and SLC38 families. Here, we analyse the functions of SLC36 family member, SLC36A4, otherwise known as proton-assisted amino-acid transporter 4 (PAT4), in colorectal cancer. We show that independent of other major pathological factors, high PAT4 expression is associated with reduced relapse-free survival after colorectal cancer surgery. Consistent with this, PAT4 promotes HCT116 human colorectal cancer cell proliferation in culture and tumour growth in xenograft models. Inducible knockdown in HCT116 cells reveals that PAT4 regulates a form of mTORC1 with two distinct properties: first, it preferentially targets eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1), and second, it is resistant to rapamycin treatment. Furthermore, in HCT116 cells two non-essential amino acids, glutamine and serine, which are often rapidly metabolised by tumour cells, regulate rapamycin-resistant mTORC1 in a PAT4-dependent manner. Overexpressed PAT4 is also able to promote rapamycin resistance in human embryonic kidney-293 cells. PAT4 is predominantly associated with the Golgi apparatus in a range of cell types, and in situ proximity ligation analysis shows that PAT4 interacts with both mTORC1 and its regulator Rab1A on the Golgi. These findings, together with other studies, suggest that differentially localised intracellular amino-acid transporters contribute to the activation of alternate forms of mTORC1. Furthermore, our data predict that colorectal cancer cells with high PAT4 expression will be more resistant to depletion of serine and glutamine, allowing them to survive and outgrow neighbouring normal and tumorigenic cells, and potentially providing a new route for pharmacological intervention.

SREBP maintains lipid biosynthesis and viability of cancer cells under lipid- and oxygen-deprived conditions and defines a gene signature associated with poor survival in glioblastoma multiforme

Oxygen and nutrient limitation are common features of the tumor microenvironment and are associated with cancer progression and induction of metastasis. The inefficient vascularization of tumor tissue also limits the penetration of other serum-derived factors, such as lipids and lipoproteins, which can be rate limiting for cell proliferation and survival. Here we have investigated the effect of hypoxia and serum deprivation on sterol regulatory element-binding protein (SREBP) activity and the expression of lipid metabolism genes in human glioblastoma multiforme (GBM) cancer cells. We found that SREBP transcriptional activity was induced by serum depletion both in normoxic and hypoxic cells and that activation of SREBP was required to maintain the expression of fatty acid and cholesterol metabolism genes under hypoxic conditions. Moreover, expression of stearoyl-CoA desaturase, the enzyme required for the generation of mono-unsaturated fatty acids, and fatty acid-binding protein 7, a regulator of glioma stem cell function, was strongly dependent on SREBP function. Inhibition of SREBP function blocked lipid biosynthesis in hypoxic cancer cells and impaired cell survival under hypoxia and in a three-dimensional spheroid model. Finally, gene expression analysis revealed that SREBP defines a gene signature that is associated with poor survival in glioblastoma.

Tumor hypoxia induces nuclear paraspeckle formation through HIF-2α dependent transcriptional activation of NEAT1 leading to cancer cell survival

Correction to: Oncogene (2015) 34, 4482–4490; doi:10.1038/onc.2014.378; published online 24 November 2014. Following the online publication of this article, the authors have noticed a misspelt surname: S Hider should read S Haider. There is also an addition to the acknowledgements to read ‘This study makes use of data generated by the Molecular Taxonomy of Breast Cancer International Consortium, which was funded by Cancer Research UK and the British Columbia Cancer Agency Branch’. The corrected article appears in this issue. The authors would like to apologise for any inconvenience this may cause.

Tumor hypoxia induces nuclear paraspeckle formation through HIF-2α dependent transcriptional activation of NEAT1 leading to cancer cell survival

Activation of cellular transcriptional responses, mediated by hypoxia-inducible factor (HIF), is common in many types of cancer, and generally confers a poor prognosis. Known to induce many hundreds of protein-coding genes, HIF has also recently been shown to be a key regulator of the non-coding transcriptional response. Here, we show that NEAT1 long non-coding RNA (lncRNA) is a direct transcriptional target of HIF in many breast cancer cell lines and in solid tumors. Unlike previously described lncRNAs, NEAT1 is regulated principally by HIF-2 rather than by HIF-1. NEAT1 is a nuclear lncRNA that is an essential structural component of paraspeckles and the hypoxic induction of NEAT1 induces paraspeckle formation in a manner that is dependent upon both NEAT1 and on HIF-2. Paraspeckles are multifunction nuclear structures that sequester transcriptionally active proteins as well as RNA transcripts that have been subjected to adenosine-to-inosine (A-to-I) editing. We show that the nuclear retention of one such transcript, F11R (also known as junctional adhesion molecule 1, JAM1), in hypoxia is dependent upon the hypoxic increase in NEAT1, thereby conferring a novel mechanism of HIF-dependent gene regulation. Induction of NEAT1 in hypoxia also leads to accelerated cellular proliferation, improved clonogenic survival and reduced apoptosis, all of which are hallmarks of increased tumorigenesis. Furthermore, in patients with breast cancer, high tumor NEAT1 expression correlates with poor survival. Taken together, these results indicate a new role for HIF transcriptional pathways in the regulation of nuclear structure and that this contributes to the pro-tumorigenic hypoxia-phenotype in breast cancer.

Identification of a hypoxia-regulated miRNA signature in bladder cancer and a role for miR-145 in hypoxia-dependent apoptosis

BACKGROUND

Hypoxia leads to the stabilisation of the hypoxia-inducible factor (HIF) transcription factor that drives the expression of target genes including microRNAs (miRNAs). MicroRNAs are known to regulate many genes involved in tumourigenesis. The aim of this study was to identify hypoxia-regulated miRNAs (HRMs) in bladder cancer and investigate their functional significance.

METHODS

Bladder cancer cell lines were exposed to normoxic and hypoxic conditions and interrogated for the expression of 384 miRNAs by qPCR. Functional studies were carried out using siRNA-mediated gene knockdown and chromatin immunoprecipitations. Apoptosis was quantified by annexin V staining and flow cytometry.

RESULTS

The HRM signature for NMI bladder cancer lines includes miR-210, miR-193b, miR-145, miR-125-3p, miR-708 and miR-517a. The most hypoxia-upregulated miRNA was miR-145. The miR-145 was a direct target of HIF-1α and two hypoxia response elements were identified within the promoter region of the gene. Finally, the hypoxic upregulation of miR-145 contributed to increased apoptosis in RT4 cells.

CONCLUSIONS

We have demonstrated the hypoxic regulation of a number of miRNAs in bladder cancer. We have shown that miR-145 is a novel, robust and direct HIF target gene that in turn leads to increased cell death in NMI bladder cancer cell lines.

Cooling of burns: Mechanisms and models

The role of cooling in the acute management of burns is widely accepted in clinical practice, and is a cornerstone of basic first aid in burns. This has been underlined in a number of animal models. The mechanism by which it delivers its benefit is poorly understood, but there is a reduction in burns progression over the first 48 h, reduced healing time, and some subjective improvements in scarring when cooling is administered after burning. Intradermal temperature normalises within a matter of seconds to a few minutes, yet the benefits of even delayed cooling persist, implying it is not simply the removal of thermal energy from the damaged tissues. Animal models have used oedema formation, preservation of dermal perfusion, healing time and hair retention as indicators of burns severity, and have shown cooling to improve these indices, but pharmacological or immunological blockade of humoural and cellular mediators of inflammation did not reproduce the benefit of cooling. More recently, some studies of tissue from human and animal burns have shown consistent, reproducible, temporal changes in gene expression in burned tissues. Here, we review the experimental evidence of the role and mechanism of cooling in burns management, and suggest future research directions that may eventually lead to improved treatment outcomes.

Imaging tumour hypoxia with positron emission tomography

Hypoxia, a hallmark of most solid tumours, is a negative prognostic factor due to its association with an aggressive tumour phenotype and therapeutic resistance. Given its prominent role in oncology, accurate detection of hypoxia is important, as it impacts on prognosis and could influence treatment planning. A variety of approaches have been explored over the years for detecting and monitoring changes in hypoxia in tumours, including biological markers and noninvasive imaging techniques. Positron emission tomography (PET) is the preferred method for imaging tumour hypoxia due to its high specificity and sensitivity to probe physiological processes in vivo, as well as the ability to provide information about intracellular oxygenation levels. This review provides an overview of imaging hypoxia with PET, with an emphasis on the advantages and limitations of the currently available hypoxia radiotracers.

Combination of letrozole, metronomic cyclophosphamide and sorafenib is well-tolerated and shows activity in patients with primary breast cancer

PURPOSE

To assess whether the combination of letrozole, metronomic cyclophosphamide and sorafenib (LCS) is well tolerated and shows activity in primary breast cancer (BC).

METHODS

Thirteen oestrogen receptor-positive, postmenopausal, T2-4, N0-1 BC patients received the LCS combination for 6 months. In these patients we examined the pharmacokinetics of sorafenib and cyclophosphamide, toxicity of the regimen, the clinical response to therapy and changes in the levels of biologically relevant biomarkers.

RESULTS

Adequate plasma concentrations of sorafenib were achieved in patients when it was dosed in combination with L+C. The mean plasma concentrations of C were consistently lower following administration of LCS, compared with administration of L+C only. The most common drug-related grade 3/4 adverse events were skin rash (69.3%), hand-foot skin reaction (69.3%) and diarrhoea (46.1%). According to RECIST Criteria, a clinical complete response was observed in 6 of 13 patients. A significant reduction in tumour size, evaluated with MRI, was also observed between baseline and 14 days of treatment in all 13 patients (P=0.005). A significant reduction in SUV uptake, measured by (18)FDG-PET/CT, was observed in all patients between baseline and 30 days of treatment (P=0.015) and between baseline and definitive surgery (P=0.0002). Using modified CT Criteria, a response was demonstrated in 8 out of 10 evaluable patients at 30 days and in 11 out of 13 evaluable patients at the definitive surgery. A significant reduction in Ki67 expression was observed in all patients at day 14 compared with baseline (P<0.00001) and in 9 out of 13 patients at the definitive surgery compared with baseline (P<0.03). There was also a significant suppression of CD31 and VEGF-A expression in response to treatment (P=0.01 and P=0.007, respectively).

CONCLUSIONS

The LCS combination is feasible and tolerable. The tumour response and target biomarker modulation indicate that the combination is clinically and biologically active.

COX-2 expression is predictive for early relapse and aromatase inhibitor resistance in patients with ductal carcinoma in situ of the breast, and is a target for treatment

BACKGROUND

Stratification of patients for treatment of ductal carcinoma in situ (DCIS) is suboptimal, with high systemic overtreatment rates.

METHODS

A training set of 95 tumours from women with pure DCIS were immunostained for proteins involved in cell survival, hypoxia, growth factor and hormone signalling. A generalised linear regression with regularisation and variable selection was applied to a multiple covariate Cox survival analysis with recurrence-free survival 10-fold cross-validation and leave-one-out iterative approach were used to build and test the model that was validated using an independent cohort of 58 patients with pure DCIS. The clinical role of a COX-2-targeting agent was then tested in a proof-of-concept neoadjuvant randomised trial in ER-positive DCIS treated with exemestane 25 mg day(-1)± celecoxib 800 mg day(-1).

RESULTS

The COX-2 expression was an independent prognostic factor for early relapse in the training (HR 37.47 (95% CI: 5.56-252.74) P=0.0001) and independent validation cohort (HR 3.9 (95% CI: 1.8-8.3) P=0.002). There was no significant interaction with other clinicopathological variables. A statistically significant reduction of Ki-67 expression after treatment with exemestane ± celecoxib was observed (P<0.02) with greater reduction in the combination arm (P<0.004). Concomitant reduction in COX-2 expression was statistically significant in the exemestane and celecoxib arm (P<0.03) only.

CONCLUSIONS

In patients with DCIS, COX-2 may predict recurrence, aiding clinical decision making. A combination of an aromatase inhibitor and celecoxib has significant biological effect and may be integrated into treatment of COX2-positive DCIS at high risk of recurrence.

Stable isotope imaging of biological samples with high resolution secondary ion mass spectrometry and complementary techniques

Stable isotopes are ideal labels for studying biological processes because they have little or no effect on the biochemical properties of target molecules. The NanoSIMS is a tool that can image the distribution of stable isotope labels with up to 50 nm spatial resolution and with good quantitation. This combination of features has enabled several groups to undertake significant experiments on biological problems in the last decade. Combining the NanoSIMS with other imaging techniques also enables us to obtain not only chemical information but also the structural information needed to understand biological processes. This article describes the methodologies that we have developed to correlate atomic force microscopy and backscattered electron imaging with NanoSIMS experiments to illustrate the imaging of stable isotopes at molecular, cellular, and tissue scales. Our studies make it possible to address 3 biological problems: (1) the interaction of antimicrobial peptides with membranes; (2) glutamine metabolism in cancer cells; and (3) lipoprotein interactions in different tissues.

Prospective neoadjuvant analysis of PET imaging and mechanisms of resistance to Trastuzumab shows role of HIF1 and autophagy

Background:

Although Trastuzumab has improved survival of HER2+ breast cancer patients, resistance to the agent pre-exists or develops through the course of therapy. Here we show that a specific metabolism and autophagy-related cancer cell phenotype relates to resistance of HER2+ breast cancer to Trastuzumab and chemotherapy.

Methods:

Twenty-eight patients with locally advanced primary breast cancer were prospectively scheduled to received one cycle of Trastuzumab followed by a new biopsy on day 21, followed by taxol/Trastuzumab chemotherapy for four cycles before surgery. FDG PET/CT scan was used to monitor tumour response. Tissue samples were immunohistochemically analysed for metabolism and autophagy markers.

Results:

In pre-Trastuzumab biopsies, the LC3A+/HER2+ cell population was correlated with HIF1α expression (P=0.01), while GLUT1 and LC3B expression were correlated with Ki67 proliferation index (P=0.01 and P=0.01, respectively). FDG PET tumour dimensions before therapy were correlated with LC3B expression (P=0.005). Administration of Trastuzumab significantly reduced clinical and PET-detected tumour dimensions (P<0.01). An inverse association of tumour response with the percentage of cells expressing HIF1α at baseline was documented (P=0.01). Administration of Trastuzumab resulted in a decrease of the proliferation index (P=0.004), GLUT1 (P=0.04) and HER2 (P=0.01) expression. In contrast, the percentage of LC3A+/HER2+ cells was increased (P=0.01). High baseline HIF1α expression was the only parameter associated with poorer pathological response to preoperative chemotherapy (P=0.001).

Conclusions:

As the HER2+/LC3A+ phenotype, which often overexpresses HIF1α, is a major subpopulation increasing after therapy with Trastuzumab, LC3A- and HIF1α-targeting therapies should be investigated for the augmentation of anti-HER2 therapy efficacy.

Abstract BS02-1: Hypoxia metabolism in breast cancer – How to overcome resistance to anti-angiogenic therapy

Background. Hypoxia is recognised to induce a multigene programme mainly via HIF1a and also HIF2a transcription factors. Bioinformatics analysis of multiple gene array data sets in breast cancer showed a core hypoxia response programme of approximately 90 genes associated with poor outcome independently of other factors. This core response was significantly over-expressed in triple receptor negative cancers. Additionally, microRNAs associated with hypoxia were shown to give additional worse prognosis associations (mir-210). mir-210 targeted the mitochondrial iron chaperone responsible for regulation of key enzymes in the Krebs cycle and showed an adaptive response to hypoxia involving switching off the mitochondrial metabolism.

Aims and methods. To assess in human breast cancer the hypoxia transcriptome we conducted gene microarray studies before and after 2 weeks of bevacizumab 15mg/kg single dose before neoadjuvant chemotherapy. This was correlated with imaging by DCE-MRI Ktrans analysis.

Results. The study showed that high Ktrans was an excellent predictor for the biological affect of VEGF inhibition and extensive gene induction occurred, including many components of the HIF pathway, but also glycogen metabolism and lipid metabolism.

We investigated these further in xenograft models to see which of the adaption pathways may be most important for survival under hypoxic conditions. We showed that induction of CA9, a key enzyme regulating extracellular pH, was critical for survival under anti-angiogenic therapy and blocking CA9 could synergise and also produce radiosensitivity. Reactivating mitochondria under hypoxic conditions induced by angiogenesis also showed additional anti-cancer benefits and is the basis now for a new phase I study in our department.

Additionally, surprisingly, induction of glycogen and lipid storage occurred and this was essential for survival on reoxygenation and for protection against free radical damage, which greatly increased when either pathway was inhibited.

We investigated, by bioinformatic approaches, the expression of 133 key enzymes in metabolism, showed that they were strongly associated with different subtypes of breast cancer, which may help in selection of patients for future intervention studies.

To additionally define the hypoxia transcription, we conducted RNA sequencing of MCF7 cells in normoxia and mild hypoxia. This revealed marked induction of many long non-coding RNAs, suppression of all transfer RNAs and induction of novel antisense RNAs.

Conclusions. Overall, therefore, although anti-angiogenic therapy alone is now withdrawn from clinical utility in breast cancer, the massive induction of hypoxic microenvironment and synergy with many other therapeutics, suggests that as new approach using induced essentiality should be reassessed in breast cancer.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr BS02-1.

Autophagy and hypoxia in colonic adenomas related to aggressive features

AIM

The study investigated whether autophagic activity and hypoxia parallel the adenoma-carcinoma sequence.

METHOD

The study comprised 120 tubular adenomas with high-grade dysplasia, including 22 with questionable evidence of invasion, 37 with definite stromal invasion and 29 with severely dysplastic adenoma, 10 traditional serrated adenomas and 22 classical tubular adenomas lacking aggressive features. The samples were stained immunohistochemically for autophagy (LC3A and Beclin-1) and hypoxia-inducible factor1-alpha (HIF1α) markers.

RESULTS

LC3A was detected as diffuse cytoplasmic staining and as dense "stone-like" structures (SLS) within cytoplasmic vacuoles. Beclin-1 reactivity was purely cytoplasmic, whereas that of HIF1α was both cytoplasmic and nuclear. SLS counts in noninvasive, nontransformed areas of tubular adenomas were consistently low (median SLS = 0.5; 200× magnification), whereas a progressive increase was noted from areas of equivocal invasion (median SLS = 1.3; 200× magnification) and intramucosal carcinoma (median SLS = 1.4; 200× magnification) to unequivocal invasive foci (median SLS = 2.1; 200× magnification) (P < 0.0001). A similar association was shown for Beclin-1 and HIF1α expression (P < 0.05). Traditional serrated adenomas yielded low SLS counts and weak HIF1α reactivity, but high cytoplasmic LC3A and Beclin-1 expression (P < 0.01).

CONCLUSION

A hypoxia-driven autophagy in adenomatous polyps, when particularly intense and localized, is commonly associated with early invasion or severely dysplastic adenoma.

Increased pathological complete response rate after a long-term neoadjuvant letrozole treatment in postmenopausal oestrogen and/or progesterone receptor-positive breast cancer

Background:

The objective of this study was to determine the optimal scheduling of 2.5 mg daily letrozole in neoadjuvant breast cancer patients to obtain pathological complete response (pathCR) and assess Ki-67 expression as an early predictor of response.

Patients and methods:

This single institution study comprised 120 oestrogen receptor (ER)-positive postmenopausal women with primary breast cancer (clinical stage ⩾T2, N0–1), from three sequential cohorts (cohort A of 40, cohort B of 40 and cohort C of 40 patients, respectively) based on different duration of the neoadjuvant letrozole. Biological markers such as ER, progesterone receptor, HER2 and Ki-67 expression were tested at diagnosis and at definitive surgery.

Results:

A total of 89 patients (75.4%) achieved an objective response with 44 (37.3%) clinical CRs and 45 (38.1%) partial responses. The clinical CRs were significantly observed in cohort C (23 out of 40 patients, 57.5%) and B (16 out of 38 patients, 42.1%) compared with cohort A (5 out of 40 patients, 12.5%) (P-value for trend <0.001). Letrozole induced a similar significant reduction in Ki-67 index after treatment in all cohorts. The pathCR rate was significantly more frequent in cohort C (7 out of 40 patients, 17.5%) than in cohort A (1 out of 40 patients, 2.5%) and B (2 out of 40 patients, 5.0%) (P-value for trend <0.04).

Conclusion:

One-year neoadjuvant letrozole therapy leads to a higher pathCR rate and may be the optimal length of drug exposure.

miR-210 is a target of hypoxia-inducible factors 1 and 2 in renal cancer, regulates ISCU and correlates with good prognosis

BACKGROUND

Clear cell renal cancer frequently harbours von Hippel-Lindau (VHL) gene mutations, leading to stabilisation of the hypoxia-inducible factors (HIFs) and expression of their target genes. We investigated HIF-1 and HIF-2 in the regulation of microRNA-210 (miR-210), and its clinical relevance in renal tumours.

METHODS

RCC4 and 786-O renal cancer cell lines transfected with either an empty vector or functional VHL and incubated in normoxia or hypoxia were examined for miR-210 expression. Hypoxia-inducible factor siRNAs were used to examine their regulation of miR-210. Seventy-one clear cell renal tumours were sequenced for VHL mutations. Expression of miR-210, VHL, CA9, ISCU and Ki-67 were determined by immunohistochemistry and qRT-PCR.

RESULTS

In addition to HIF-1 regulating miR-210 in renal cancer, HIF-2 can regulate this microRNA in the absence of HIF-1. MicroRNA-210 is upregulated in renal cancer compared with normal renal cortex tissue. MicroRNA-210 correlates negatively with its gene target ISCU at the protein and mRNA level. MicroRNA-210 correlated with positive outcome variables and negatively with Ki-67.

CONCLUSION

We provide further evidence of miR-210 activity in vivo, and show that high miR-210 expression is associated with better clinico-pathological prognostic factors.

Abstract P1-06-01: Upregulation of metabolism as a potential resistance mechanism to bevacizumab in primary breast cancer

Background: Recently the FDA has withdrawn the indication for bevacizumab in metastatic breast cancer after several clinical studies failed to demonstrate an overall survival benefit. These studies however did report an increase in response rates to chemotherapy and improvement in progression free survival, suggesting a pattern of response to the drug followed by the development of resistance. We have little knowledge of the molecular mechanisms driving the development of resistance to bevacizumab. To better understand these mechanisms, we have conducted a window of opportunity study using a single cycle of bevacizumab with detailed pharmacodynamic assessments using gene expression arrays and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI).

Methods: After ethical approval, 47 newly diagnosed locally advanced breast cancer patients were prospectively enrolled in this trial. Patients received single dose bevacizumab (15mg/ kg) 2 weeks prior to neoadjuvant chemotherapy and underwent core biopsies for gene expression and immunohistochemistry analysis and DCE-MRI scans before and 2 weeks after bevacizumab. 35 patients who had invasive ductal carcinoma together with good quality MRI scans and core biopsies before and after bevacizumab were included in this analysis. Pharmacokinetic (PK) modelling techniques were used to quantify PK parameters (Ktrans, kep, ve) from the DCE-MRI data. Gene expression profiling was performed using the Affymetrix Human Exon 1.0 ST arrays.

Results: The majority of patients (28/35) showed a significant reduction in vessel permeability and blood flow of at least 30% following bevacizumab, with a mean decrease in the forward transfer constant (P &lt; 0.0001) and the reverse rate constant kep (P &lt; 0.0001). From gene expression and immunohistochemistry analyses, we identified several key metabolism-related genes that are significantly up-regulated after bevacizumab treatment, including pyruvate dehydrogenase kinase isozyme 1 (PDK1) (fig.1) and carbonic anhydrase 9 (CA9). In addition, we found a number of interesting genes that are down-regulated after bevacizumab treatment, including sulfatase-1 (SULF1), and cyclin E1 (CCNE1).

Discussion: This study highlights that the combination of DCE-MRI and gene expression arrays can lead to an improved understanding of the molecular mechanisms governing response and resistance to anti-angiogenic therapy. Heterogeneity of response to bevacizumab was demonstrated, with some tumours showing increases or no change in Ktrans and others marked reductions, which may be of value in early stratification for therapy maintenance. Furthermore, the gene expression analysis showed activation of pathways, which could contribute to the development of resistance. For example, we observed significant up regulation of genes involved in regulating the switch from mitochondrial metabolism to glycolysis, such as PDK1. This suggests that using bevacizumab with the other targeted agents such as Dichloroacetate, a PDK1 inhibitor might be helpful in overcoming the development of resistance and ultimately lead to improved patient survival. Our preclinical studies strongly support this possibility.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P1-06-01.

Igf2 ligand dependency of Pten(+/-) developmental and tumour phenotypes in the mouse

The tumour suppressor PTEN is a key negative regulator of the PI3K-Akt pathway, and is frequently either reduced or lost in human tumours. Murine genetic studies have confirmed that reduction of Pten promotes tumourigenesis in multiple organs, and demonstrated dependency of tumour development on the activation of downstream components such as Akt. Insulin-like growth factors (IGFs) act via IGF1R to activate the PI3K-Akt pathway, and are commonly upregulated in cancer. A context-dependent interplay between IGFs and PTEN exists in normal tissue and tumours; increased IGF2 ligand supply induces Pten expression creating an autoregulatory negative feedback loop, whereas complete loss of PTEN may either cooperate with IGF overexpression in tumour promotion, or result in desensitisation to IGF ligand. However, it remains unknown whether neoplasia associated with Pten loss is dependent on upstream IGF ligand supply in vivo. We evaluated this by generation of Pten^+/− mice with differing allelic dosage of Igf2, an imprinted gene encoding the potent embryonic and tumour growth factor Igf2. We show that biallelic Igf2 supply potentiates a previously unreported Pten^+/− placental phenotype and results in strain-dependent cardiac hyperplasia and neonatal lethality. Importantly, we also show that the effects of Pten loss in vivo are modified by Igf2 supply, as lack of Igf2 results in extended survival and delayed tumour development while biallelic supply is associated with reduced lifespan and accelerated neoplasia in females. Furthermore, we demonstrate that reduction of PTEN protein to heterozygote levels in human MCF7 cells is associated with increased proliferation in response to IGF2, and does not result in desensitisation to IGF2 signalling. These data indicate that the effects of Pten loss at heterozygote levels commonly observed in human tumours are modified by Igf2 ligand, and emphasise the importance of the evaluation of upstream pathways in tumours with Pten loss.

The cost-effectiveness of adjuvant chemotherapy for early breast cancer: A comparison of no chemotherapy and first, second, and third generation regimens for patients with differing prognoses

BACKGROUND

The risk of recurrence following surgery in women with early breast cancer varies, depending upon prognostic factors. Adjuvant chemotherapy reduces this risk; however, increasingly effective regimens are associated with higher costs and toxicity profiles, making it likely that different regimens may be cost-effective for women with differing prognoses. To investigate this we performed a cost-effectiveness analysis of four treatment strategies: (1) no chemotherapy, (2) chemotherapy using cyclophosphamide, methotrexate, and fluorouracil (CMF) (a first generation regimen), (3) chemotherapy using Epirubicin-CMF (E-CMF) or fluorouracil, epirubicin, and cyclophosphamide (FEC60) (a second generation regimens), and (4) chemotherapy with FEC60 followed by docetaxel (FEC-D) (a third generation regimen). These adjuvant chemotherapy regimens were used in three large UK-led randomised controlled trials (RCTs).

METHODS

A Markov model was used to simulate the natural progression of early breast cancer and the impact of chemotherapy on modifying this process. The probability of a first recurrent event within the model was estimated for women with different prognostic risk profiles using a parametric regression-based survival model incorporating established prognostic factors. Other probabilities, treatment effects, costs and quality of life weights were estimated primarily using data from the three UK-led RCTs, a meta-analysis of all relevant RCTs, and other published literature. The model predicted the lifetime costs, quality adjusted life years (QALYs) and cost-effectiveness of the four strategies for women with differing prognoses. Sensitivity analyses investigated the impact of uncertain parameters and model assumptions.

FINDINGS

For women with an average to high risk of recurrence (based upon prognostic factors and any other adjuvant therapies received), FEC-D appeared most cost-effective assuming a threshold of £20,000 per QALY for the National Health Service (NHS). For younger low risk women, E-CMF/FEC60 tended to be the optimal strategy and, for some older low risk women, the model suggested a policy of no chemotherapy was cost-effective. For no patient group was CMF chemotherapy the preferred option. Sensitivity analyses demonstrated cost-effectiveness results to be particularly sensitive to the treatment effect estimate for FEC-D and the future price of docetaxel.

INTERPRETATION

To our knowledge, this analysis is the first cost-effectiveness comparison of no chemotherapy, and first, second, and third generation adjuvant chemotherapy regimens for early breast cancer patients with differing prognoses. The results demonstrate the potential for different treatment strategies to be cost-effective for different types of patients. These findings may prove useful for policy makers attempting to formulate cost-effective treatment guidelines in the field of early breast cancer.

Continuous low-dose cyclophosphamide and methotrexate combined with celecoxib for patients with advanced cancer

BACKGROUND

Combined therapy of metronomic cyclophosphamide, methotrexate and high-dose celecoxib targeting angiogenesis was used in a phase II trial.

METHODS

Patients with advanced cancer received oral cyclophosphamide 50 mg o.d., celecoxib 400 mg b.d. and methotrexate 2.5 mg b.d. for two consecutive days each week. Response was determined every 8 weeks; toxicity was evaluated according to CTC version 2.0. Plasma markers of inflammation, coagulation and angiogenesis were measured.

RESULTS

Sixty-seven of 69 patients were evaluable for response. Twenty-three patients had stable disease (SD) after 8 weeks, but there were no objective responses to therapy. Median time to progression was 57 days. There was a low incidence of toxicities. Among plasma markers, levels of tissue factor were higher in the SD group of patients at baseline, and levels of both angiopoietin-1 and matrix metalloproteinase-9 increased in the progressive disease group only. There were no changes in other plasma markers.

CONCLUSION

This metronomic approach has negligible activity in advanced cancer albeit with minimal toxicity. Analysis of plasma markers indicates minimal effects on endothelium in this trial. These data for this particular regimen do not support basic tenets of metronomic chemotherapy, such as the ability to overcome resistant tumours by targeting the endothelium.

Development of a new bimodal imaging methodology: a combination of fluorescence microscopy and high-resolution secondary ion mass spectrometry

In this paper, we present a new experimental methodology to combine mass spectrometry (NanoSIMS) with fluorescence microscopy to provide subcellular information on the location of small molecules in cultured cells. We demonstrate this by comparing the distribution of 5-bromo-2-deoxyuridine in the same cells given by both NanoSIMS analysis and by fluorescence immunohistochemistry. Fiducial markers in the substrates ensured that the images formed by SIMS mapping of bromine ions could be co-registered exactly with images from fluorescence microscopy. The NanoSIMS was shown to faithfully reproduce the information from fluorescence microscopy, but at a much higher spatial resolution. We then show preliminary SIMS images on the distribution of ATN-224, a therapeutic copper chelator for which there is no fluorescent marker, co-registered with conventional Lysotracker and Hoechst stains on the same cells.

Abstract P2-02-07: Predicting Response to Bevacizumab Therapy in Primary Breast Cancer Using Dynamic Contrast-Enhanced Magnetic Resonance Imaging

Background: Anti-angiogenic therapy holds much promise for the treatment of breast cancer. In practice however, only a subset of patients who receive these drugs demonstrate a significant response to therapy. A key challenge therefore is to elucidate markers that are predictive of response to anti-angiogenic agents such as bevacizumab, and which would enable the selection of patients who would get the most benefit from these expensive therapies.

Materials and Methods: We used high temporal resolution dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) to assess tumor vascularity in 20 patients with primary breast cancer. Patients were imaged both before and two weeks after single dose Bevacizumab therapy (15mg/kg). Pharmacokinetic modelling techniques were used to quantify the volume transfer constant Ktrans, the rate constant kep, and the fractional volume of the extra-vascular extracellular space ve. Specifically, we used Tofts model with a population-based arterial input function (modified Fritz-Hansen) to model the contrast agent concentration time courses on a voxel-wise basis. Non-enhancing voxels were detected automatically with the use of a Bayesian noise model, and the corresponding pharmacokinetic parameter values for these voxels were set to zero. The median pharmacokinetic parameter values over the tumor volumes of interest were then computed both pre-and post Bevacizumab. Results: We found marked variation across patients in the baseline level and percentage change in median Ktrans, kep and ve following Bevacizumab. In particular, median Ktrans at baseline ranged form 0.12 to 0.88. Changes in median Ktrans varied from −97% to +19% across all patients, with an average change of −49%. Notably, we found a highly significant negative correlation (r = −0.92, P = 1e-08) between the absolute change in median Ktrans and the median Ktrans at baseline. In particular, tumors with a high median Ktrans at baseline demonstrated the greatest change in Ktrans following Bevacizumab therapy, whereas tumors with low median Ktrans at baseline demonstrated relatively little change in Ktrans. Discussion: Although Ktrans is a complex function of vessel permeability, surface area, and tumor blood flow, it has previously been demonstrated to be a reliable biomarker of response to anti-angiogenic therapy in a number of different cancers. Our results illustrate that therapy-induced changes in Ktrans can be predicted from the value of Ktrans at baseline, and hence DCE-MRI scans may enable the selection of primary breast cancer patients who show the greatest response to single-dose Bevacizumab therapy. Whether this will translate into longer term benefit and improvements in outcome for patients remains to be shown. The relationship between baseline and pre-/post-therapy change in Ktrans with the corresponding changes in gene expression is currently under study in a larger number of patients. Figure available in online version.

Estimation and external validation of a new prognostic model for predicting recurrence-free survival for early breast cancer patients in the UK

Background:

We aimed to estimate and externally validate a new UK-specific prognostic model for predicting the long-term risk of a first recurrent event (local recurrence, metastatic recurrence, or second primary breast cancer) in women diagnosed with early breast cancer.

Methods:

Using data on the prognostic characteristics and outcomes of 1844 women treated for early breast cancer at the Churchill Hospital in Oxford, parametric regression-based survival analysis was used to estimate a prognostic model for recurrence-free survival. The model, which incorporated established prognostic factors, was externally validated using independent data. Its performance was compared with that of the Nottingham Prognostic Index (NPI) and Adjuvant! Online.

Results:

The number of positive axillary lymph nodes, tumour grade, tumour size and patient age were strong predictors of recurrence. Oestrogen receptor (ER) positivity was shown to afford a moderate protective effect. The model was able to separate patients into distinct prognostic groups, and predicted well at the patient level, mean Brier Accuracy Score=0.17 (s.e.=0.004) and overall C=0.745 (95% CI, 0.717–0.773). Its performance diminished only slightly when applied to a second independent data set. When compared with the NPI, the model was able to better discriminate between women with excellent and good prognoses, and it did not overestimate 10-year recurrence-free survival to the extent observed for Adjuvant! Online.

Conclusion:

The model estimated here predicts well at both the individual patient and group levels, and appears transportable to patients treated at other UK hospitals. Its parametric form permits long-term extrapolation giving it an advantage over other prognostic tools currently in use. A simple point scoring system and reference table allow 5-, 10-, and 15-year predictions from the model to be quickly and easily estimated. The model is also available to download as an interactive computer program.

STUDIES ON IMMUNOLOGICAL RELATIONSHIPS AMONG THE PNEUMOCOCCI : II. A COMPARISON OF THE ANTIBODY RESPONSES OF MICE AND OF RABBITS TO IMMUNIZATION WITH TYPICAL TYPE III PNEUMOCOCCI AND TO IMMUNIZATION WITH A RELATED STRAIN

The paper reports an experimental comparison of the antibody responses of mice and of rabbits to immunization with typical Type III pneumococci and a strain related to Type III. The results as a whole show that the relative antigenic effectiveness of these two kinds of related pneumococci, is different in different animals. In rabbits the strain related to but not identical with Type III elicits the better response; in mice, the typical Type III strain is more effective. These relationships furnish an example of the influence of the species of animal upon the effectiveness of even closely related bacterial antigens.

An oncogenic role of eIF3e/INT6 in human breast cancer

Altered expression of the eukaryotic translation initiation factor 3 (eIF3) subunit eIF3e/INT6 has been described in various types of human cancer, but the nature of its involvement in tumorigenesis is not yet clear. Using immunohistochemical analysis of 81 primary breast cancers, we found that high tumor grade correlated significantly with elevated cytoplasmic eIF3e level in epithelial tumor cells. Analysis of protein synthesis after siRNA-mediated knockdown in breast cancer cell lines indicated that eIF3e is not required for bulk translation. Microarray analysis of total and polysomal RNAs nonetheless identified distinct sets of mRNAs regulated either positively or negatively by eIF3e; functional classification of these revealed a marked enrichment of genes involved in cell proliferation, invasion and apoptosis. Validated mRNA targets regulated positively at the translational level by eIF3e included urokinase-type plasminogen activator and apoptotic regulator BCL-XL, whereas synthesis of proteins including the mitotic checkpoint component MAD2L1 was negatively regulated. Finally, eIF3e-depleted breast carcinoma cells showed reduced in vitro invasion and proliferation. Taken together, our study data suggest that eIF3e has a positive role in breast cancer progression. It regulates the translation, and in some cases abundance, of mRNAs involved in key aspects of cancer cell biology.

Large meta-analysis of multiple cancers reveals a common, compact and highly prognostic hypoxia metagene

Background:

There is a need to develop robust and clinically applicable gene expression signatures. Hypoxia is a key factor promoting solid tumour progression and resistance to therapy; a hypoxia signature has the potential to be not only prognostic but also to predict benefit from particular interventions.

Methods:

An approach for deriving signatures that combine knowledge of gene function and analysis of in vivo co-expression patterns was used to define a common hypoxia signature from three head and neck and five breast cancer studies. Previously validated hypoxia-regulated genes (seeds) were used to generate hypoxia co-expression cancer networks.

Results:

A common hypoxia signature, or metagene, was derived by selecting genes that were consistently co-expressed with the hypoxia seeds in multiple cancers. This was highly enriched for hypoxia-regulated pathways, and prognostic in multivariate analyses. Genes with the highest connectivity were also the most prognostic, and a reduced metagene consisting of a small number of top-ranked genes, including VEGFA, SLC2A1 and PGAM1, outperformed both a larger signature and reported signatures in independent data sets of head and neck, breast and lung cancers.

Conclusion:

Combined knowledge of multiple genes' function from in vitro experiments together with meta-analysis of multiple cancers can deliver compact and robust signatures suitable for clinical application.

Circulating tumour cells demonstrate an altered response to hypoxia and an aggressive phenotype

Background:

Tumours contain hypoxic regions that select for an aggressive cell phenotype; tumour hypoxia induces metastasis-associated genes. Treatment refractory patients with metastatic cancer show increased numbers of circulating tumour cells (CTCs), which are also associated with disease progression. The aim of this study was to examine the as yet unknown relationship between hypoxia and CTCs.

Methods:

We generated human MDA-MB-231 orthotopic xenografts and, using a new technology, isolated viable human CTCs from murine blood. The CTCs and parental MDA-MB-231 cells were incubated at 21 and 0.2% (hypoxia) oxygen, respectively. Colony formation was assayed and levels of hypoxia- and anoxia-inducible factors were measured. Xenografts generated from CTCs and parental cells were compared.

Results:

MDA-MB-231 xenografts used to generate CTCs were hypoxic, expressing hypoxia factors: hypoxia-inducible factor1 alpha (HIF1α) and glucose transporter protein type 1 (GLUT1), and anoxia-induced factors: activating transcription factor 3 and 4 (ATF3 and ATF4). Parental MDA-MB-231 cells induced ATF3 in hypoxia, whereas CTCs expressed it constitutively. Asparagine synthetase (ASNS) expression was also higher in CTCs. Hypoxia induced ATF4 and the HIF1α target gene apelin in CTCs, but not in parental cells. Hypoxia induced lower levels of carbonic anhydrase IX (CAIX), GLUT1 and BCL2/adenovirus E1B 19-KD protein-interacting protein 3 (BNIP3) proteins in CTCs than in parental cells, supporting an altered hypoxia response. In chronic hypoxia, CTCs demonstrated greater colony formation than parental cells. Xenografts generated from CTCs were larger and heavier, and metastasised faster than MDA-MB-231 xenografts.

Conclusion:

CTCs show an altered hypoxia response and an enhanced aggressive phenotype in vitro and in vivo.

Mechanisms of multidrug resistance in cancer treatment

Advanced breast cancer responds to a range of cytotoxic agents, but resistance always develops. Understanding the mechanisms of resistance may provide new therapeutic options. There are several major groups of resistance mechanisms. 1) The multidrug resistant phenotype. This is due to a membrane pump that can extrude a wide range of anticancer drugs--the P-glycoprotein. It is inhibited by a range of clinically used calcium channel blockers such as nifedipine and verapamil. Several other membrane proteins of 180 KD, 170 KD, 300 KD and 85 KD have been reported and are associated with MDR. 2) Glutathione transferences and detoxification mechanisms. These are a multigene family of enzymes that conjugate glutathione to chemically reactive groups. There are 3 major groups of enzymes--acidic, basic and neutral. They have been implicated in resistance to doxorubicin, melphalan cisplatinum chlorambucil and other alkylating agents. Other protecting systems include metallothionein and selenium dependent glutathione peroxidase. HSP27 confers doxorubicin resistance. 3) Topoisomerase II. DNA topoisomerases are involved in several aspects of DNA metabolism in particular genetic recombination, DNA transcription, chromosome segregation. They are a target for doxorubicin, mitoxantrone, VP16. Low levels of expression are associated with resistance. However, it is oestrogen inducible and this may be of therapeutic value. A novel topo IIb which is more drug resistant has been reported. 4) DNA repair. A score or more of genes are involved in the repair of DNA damage by drugs and radiation. Defective DNA repair may predispose to cancer of the breast and be responsible for adverse radiation reactions. Enhanced repair has been shown to be a mechanism of cisplatinum resistance. Several genes are inducible by DNA damage and may confer resistance e.g. A45. 5) Drug activation. Mitomycin C as well as cyclophosphamide and VP16 require activation for their effects. Low levels of cytochrome p450 reductase are associated with MMC resistance.

Zinc presence in invasive ductal carcinoma of the breast and its correlation with oestrogen receptor status

Zinc is known to play an important role in many cellular processes, and the levels of zinc are controlled by specific transporters from the ZIP (SLC39A) influx transporter group and the ZnT (SLC30A) efflux transporter group. The distribution of zinc was measured in 59 samples of invasive ductal carcinoma of breast using synchrotron radiation micro probe x-ray fluorescence facilities. The samples were formalin fixed paraffin embedded tissue micro arrays (TMAs) enabling a high throughput of samples and allowing us to correlate the distribution of trace metals with tumour cell distribution and, for the first time, important biological variables. The samples were divided into two classes, 34 oestrogen receptor positive (ER+ve) and 25 oestrogen receptor negative (ER-ve) based on quantitative immunohistochemistry assessment. The overall levels of zinc (i.e. in tumour and surrounding tissue) in the ER+ve samples were on average 60% higher than those in the ER-ve samples. The zinc levels were higher in the ER+ve tumour areas compared to the ER-ve tumour areas with the mean levels in the ER+ve samples being approximately 80% higher than the mean ER-ve levels. However, the non-tumour tissue regions of the samples contained on average the same levels of zinc in both types of breast cancers. The relative levels of zinc in tumour areas of the tissue were compared with levels in areas of non-tumour surrounding tissue. There was a significant increase in zinc in the tumour regions of the ER+ve samples compared to the surrounding regions (P < 0.001) and a non-significant increase in the ER-ve samples. When comparing the increase in zinc in the tumour regions expressed as a percentage of the surrounding non-tumour tissue zinc level in the same sample, a significant difference between the ER+ve and ER-ve samples was found (P < 0.01).

Hypoxia-inducible factor-1alpha and -2alpha are expressed in most rectal cancers but only hypoxia-inducible factor-1alpha is associated with prognosis

The hypoxia-mediated response of tumours is a major determining factor in growth and metastasis. Understanding tumour biology under hypoxic conditions is crucial for the development of antiangiogenic therapy. Using one of the largest cohorts of rectal adenocarcinomas to date, this study investigated hypoxia-inducible factor-1α (HIF-1α) and HIF-2α protein expression in relation to rectal cancer recurrence and cancer-specific survival. Patients (n=90) who had undergone surgery for rectal adenocarcinoma, with no prior neoadjuvant therapy or metastatic disease, and for whom adequate follow-up data were available were selected. Microvessel density (MVD), HIF-1α and HIF-2α expressions were assessed immunohistologically with the CD34 antibody for vessel identification and the NB100-131B and NB100-132D3 antibodies for HIF-1α and HIF-2α, respectively. In a multifactorial analysis, results were correlated with tumour stage, recurrence rate and long-term survival. Microvessel density was higher across T and N stages (P<0.001) and associated with poor survival (hazard ratio (HR)=8.7, P<0.005) and decreased disease-free survival (HR=4.7, P<0.005). hypoxia-inducible factor-1α and -2α were expressed in >50% of rectal cancers (HIF-1α, 54%, 48/90; HIF-2α, 64%, 58/90). HIF-1α positivity was associated with both TNM stage (P<0.05) and vascular invasion (P<0.005). In contrast, no associations were shown between HIF-2α expression and any pathological features, and HIF-1α positivity had no effect on outcome. The study showed an independent association between HIF-1α expression and advanced TNM stage with poor outcome. Our results indicate that HIF-1α, but not HIF-2α, might be used as a marker of prognosis, in addition to methods currently used, to enhance patient management.

Assessment of microvessel density and carbonic anhydrase-9 (CA-9) expression in rectal cancer

AIM

The mechanism by which neoplasias respond to hypoxia determines their biological behavior and prognosis. Understanding the biology of tumors under hypoxic conditions is crucial for the development of anti-angiogenic therapy. Using the largest cohort of rectal adenocarcinomas to date, this study aimed to assess microvessel density (MVD) and carbonic anhydrase-9 (CA-9) expression and to correlate the results with recurrence and cancer-specific survival.

MATERIALS AND METHODS

Patients (n=101) who underwent surgery for rectal adenocarcinoma without previous neoadjuvant therapy or metastatic disease were selected. MVD and CA-9 expression were assessed immunohistologically by using the CD34 antibody and the MN/CA9 M75 antibody, respectively. In a multifactorial analysis, the results were correlated with tumor stage, recurrence rate, and long-term survival.

RESULTS

MVD was higher with increased T- and N-stages (p<0.01) and associated positively with poor survival (hazard ratio (HR) 1.3 per 10 vessel increase, p<0.01). CA-9 was expressed in 73% of cancers. Negative lymph node status correlated with CA-9 positivity (p<0.05), reflected in a higher rate of CA-9 positivity in earlier Dukes' stages (p<0.05). CA-9 positivity across tumor node metastasis (TNM) stages approached significance (Stage I/II: 80% CA-9 positive vs. 20% CA-9 negative; Stage III: 63% CA-9 positive vs. 37% negative, p=0.051). A trend was seen towards better cancer-specific survival in patients with CA-9 positive carcinomas (HR 0.51, p=0.07) on univariate analysis.

DISCUSSION

MVD was higher in more advanced T- and N-stages and may be used as a determinant of survival in patients with rectal adenocarcinomas. CA-9 expression was seen more often in earlier Dukes' stages, possibly representing an early tumor hypoxic response. CA-9 expression by adenocarcinoma cells may confer long-term survival advantage in surgically treated rectal cancer.