Clare Orange

High Expression of Sphingosine 1-Phosphate Receptors, S1P1 and S1P3, Sphingosine Kinase 1, and Extracellular Signal-Regulated Kinase-1/2 Is Associated with Development of Tamoxifen Resistance in Estrogen Receptor-Positive Breast Cancer Patients

Various studies in cell lines have previously demonstrated that sphingosine kinase 1 (SK1) and extracellular signal-regulated kinase 1/2 (ERK-1/2) interact in an estrogen receptor (ER)-dependent manner to influence both breast cancer cell growth and migration. A cohort of 304 ER-positive breast cancer patients was used to investigate the prognostic significance of sphingosine 1-phosphate (S1P) receptors 1, 2, and 3 (ie, S1P1, S1P2, and S1P3), SK1, and ERK-1/2 expression levels. Expression levels of both SK1 and ERK-1/2 were already available for the cohort, and S1P1, S1P2, and S1P3 levels were established by immunohistochemical analysis. High membrane S1P1 expression was associated with shorter time to recurrence (P=0.008). High cytoplasmic S1P1 and S1P3 expression levels were also associated with shorter disease-specific survival times (P=0.036 and P=0.019, respectively). Those patients with tumors that expressed high levels of both cytoplasmic SK1 and ERK-1/2 had significantly shorter recurrence times than those that expressed low levels of cytoplasmic SK1 and cytoplasmic ERK-1/2 (P=0.00008), with a difference in recurrence time of 10.5 years. Similarly, high cytoplasmic S1P1 and cytoplasmic ERK-1/2 expression levels (P=0.004) and high cytoplasmic S1P3 expression and cytoplasmic ERK-1/2 expression levels (P=0.004) were associated with shorter recurrence times. These results support a model in which the interaction between SK1, S1P1, and/or S1P3 and ERK-1/2 might drive breast cancer progression, and these findings, therefore, warrant further investigation.

Epigenetic downregulation of human disabled homolog 2 switches TGF-beta from a tumor suppressor to a tumor promoter

The cytokine TGF-beta acts as a tumor suppressor in normal epithelial cells and during the early stages of tumorigenesis. During malignant progression, cancer cells can switch their response to TGF-beta and use this cytokine as a potent oncogenic factor; however, the mechanistic basis for this is poorly understood. Here we demonstrate that downregulation of disabled homolog 2 (DAB2) gene expression via promoter methylation frequently occurs in human squamous cell carcinomas (SCCs) and acts as an independent predictor of metastasis and poor prognosis. Retrospective microarray analysis in an independent data set indicated that low levels of DAB2 and high levels of TGFB2 expression correlate with poor prognosis. Immunohistochemistry, reexpression, genetic knockout, and RNAi silencing studies demonstrated that downregulation of DAB2 expression modulated the TGF-beta/Smad pathway. Simultaneously, DAB2 downregulation abrogated TGF-beta tumor suppressor function, while enabling TGF-beta tumor-promoting activities. Downregulation of DAB2 blocked TGF-beta-mediated inhibition of cell proliferation and migration and enabled TGF-beta to promote cell motility, anchorage-independent growth, and tumor growth in vivo. Our data indicate that DAB2 acts as a tumor suppressor by dictating tumor cell TGF-beta responses, identify a biomarker for SCC progression, and suggest a means to stratify patients with advanced SCC who may benefit clinically from anti-TGF-beta therapies.

Comparison of visual and automated assessment of Ki-67 proliferative activity and their impact on outcome in primary operable invasive ductal breast cancer.

Background:Immunohistochemistry of Ki-67 protein is widely used to assess tumour proliferation, and is an established prognostic factor in breast cancer. There is interest in automating the assessment of Ki-67 labelling index (LI) with possible benefits in handling increased workload, with improved accuracy and precision.Patients and methods:Visual and automated assessment of Ki-67 LI and survival were examined in patients with primary operable invasive ductal breast cancer. Tissue microarrays (n=379 patients) immunostained for Ki-67 were scored visually and automatically with the Slidepath Tissue IA system.Results:Visual and automated Ki-67 LI were in excellent agreement (ICCC=0.96, P<0.001). On univariate analysis, visual (P<0.001) and automated Ki67 LI (P<0.05) were associated with cancer-specific survival in patients with invasive ductal breast cancer overall and in patients who received endocrine therapy (Tamoxifen) (P<0.01 for visual and P<0.05 for automated scoring).Conclusion:Automated assessment of Ki-67 LI would appear to be comparable to visual Ki-67 LI. However, automated Ki-67 LI assessment was inferior in predicting cancer survival in patients with breast cancer, including patients who received Tamoxifen.

NFκB signalling is upregulated in a subset of castrate-resistant prostate cancer patients and correlates with disease progression.

Background:Cell line models suggest that activation of NFκB is associated with progression of prostate cancer. This pathway may be a therapeutic target if these observations translate to clinical specimens.Methods:Immunohistochemistry measured NFκBp65 (p65), NFκBp65 nuclear localisation signal (NLS), NFκBp65 phosphorylated at ser 276 (p65ser276), NFκBp65 phosphorylated at ser 536 (p65ser536), IκBα phosphorylated at ser 32/36 (pIκBαser32/36) and MMP-9 protein expression in 61 matched hormone naive prostate cancer (HNPC) and castrate-resistant prostate cancer (CRPC) tumours. Animal and cell models were used to investigate the role of NFκB inhibition in prostate carcinogenesis.Results:In HNPC tumours, NLS expression significantly associated with a shorter time to disease recurrence and disease-specific death. In CRPC tumours p65, pIκBαser32/36 and MMP-9 expression significantly associated with shorter time to death from disease recurrence and shorter disease-specific death. MMP-9 and pIκBαser32/36 expression significantly associated with metastases at recurrence and were independent of Gleason sum and prostate-specific antigen at recurrence. Expression of phosphorylated Akt was associated with increased p65 activation in mouse models and inhibition of NFκB in LNCaP cells significantly reduced cellular proliferation and induced apoptosis.Conclusion:These results provide further evidence that the NFκB pathway could be exploited as a target for CRPC.

Expression of sphingosine 1-phosphate receptor 4 and sphingosine kinase 1 is associated with outcome in oestrogen receptor-negative breast cancer

Background:We previously reported that sphingosine 1-phosphate receptor 4 (S1P4) is expressed and stimulates the ERK-1/2 pathway via a human epidermal growth factor receptor 2 (HER2)-dependent mechanism in oestrogen receptor-negative (ER−) MDA-MB-453 breast cancer cells.Methods:Clinical relevance of S1P4 and sphingosine kinase 1 (SK1, which catalyses the formation of S1P) was assessed in a cohort of 140 ER− breast tumours by immunohistochemistry (IHC) and the weighted histoscore method. Additional evidence for a functional interaction between S1P4 and SK1 and between HER2 and SK1 was obtained using MDA-MB-453 cells.Results:High S1P4 expression is associated with shorter disease-free (P=0.014) and disease-specific survival (P=0.004), and was independent on multivariate analysis. In addition, patients with tumours that contain high and low levels of SK1 and S1P4, respectively, have a significantly shorter disease-free survival (P=0.043) and disease-specific survival (P=0.033) compared with patients whose tumours contain both low S1P4 and SK1 levels. In addition, high tumour expression of SK1 was significantly associated with shorter disease-specific survival (P=0.0001) in patients with HER2-positive tumours. Treatment of MDA-MB-453 cells with the SK1 inhibitor, SKi (2-(p-hydroxyanilino)-4-(p-chlorophenyl)thiazole) reduced the basal and S1P/S1P4-induced activation of ERK-1/2 and altered HER2 trafficking in these cells.Conclusion:These findings highlight an important role for S1P4 and SK1 in ER− breast cancer progression.

RUNX2 correlates with subtype-specific breast cancer in a human tissue microarray, and ectopic expression of Runx2 perturbs differentiation in the mouse mammary gland

RUNX2, a master regulator of osteogenesis, is oncogenic in the lymphoid lineage; however, little is known about its role in epithelial cancers. Upregulation of RUNX2 in cell lines correlates with increased invasiveness and the capacity to form osteolytic disease in models of breast and prostate cancer. However, most studies have analysed the effects of this gene in a limited number of cell lines and its role in primary breast cancer has not been resolved. Using a human tumour tissue microarray, we show that high RUNX2 expression is significantly associated with oestrogen receptor (ER)/progesterone receptor (PR)/HER2-negative breast cancers and that patients with high RUNX2 expression have a poorer survival rate than those with negative or low expression. We confirm RUNX2 as a gene that has a potentially important functional role in triple-negative breast cancer. To investigate the role of this gene in breast cancer, we made a transgenic model in which Runx2 is specifically expressed in murine mammary epithelium under the control of the mouse mammary tumour virus (MMTV) promoter. We show that ectopic Runx2 perturbs normal development in pubertal and lactating animals, delaying ductal elongation and inhibiting lobular alveolar differentiation. We also show that the Runx2 transgene elicits age-related, pre-neoplastic changes in the mammary epithelium of older transgenic animals, suggesting that elevated RUNX2 expression renders such tissue more susceptible to oncogenic changes and providing further evidence that this gene might have an important, context-dependent role in breast cancer.

Upregulation of MAPK pathway is associated with survival in castrate-resistant prostate cancer

Background:Recent evidence has implicated the MAP kinase (MAPK) pathway with the development of castrate-resistant prostate cancer (CRPC). We have previously reported gene amplification of critical members of this pathway with the development of castrate-resistant disease. In addition, we have shown that rising Raf-1 expression, with the development of CRPC, influences time to biochemical relapse. We therefore sought to further analyse the role of both Raf-1 and its downstream target MAPK in the molecular pathogenesis of CRPC.Methods:Protein expression of Raf-1 and MAPK, including their activation status, was analysed using immunohistochemistry in a database of 65 paired tumour specimens obtained before and after the development of CRPC and correlated with other members of the pathway.Results:Patients whose nuclear expression of MAPK rose with the development of CRPC had a significantly shorter median time to death following biochemical relapse (1.40 vs 3.00 years, P=0.0255) as well as reduced disease-specific survival when compared with those whose expression fell or remained unchanged (1.16 vs 2.62 years, P=0.0005). Significant correlations were observed between protein expression of Raf-1 and MAPK with the type 1 receptor tyrosine kinases, Her2 and epidermal growth factor receptor, as well as the transcription factor AP-1 in CRPC tumours.Conclusion:We conclude that the Her2/Raf-1/MAPK/AP-1 axis may promote the development of CRPC, leading to early relapse, and reduced disease-specific survival. In addition, members of the pathway may act as novel therapeutic and/or diagnostic targets for prostate cancer.

Abstract 1: Loss of STAT1 predicts outcome in prostate cancer patients at diagnosis by regulating the proliferation of prostate epithelial cells.

Proceedings: AACR 104th Annual Meeting 2013; Apr 6-10, 2013; Washington, DC Background. Dysregulation of STAT factors along with the negative feedback regulators of the Janus-activated kinase (JAK)-STAT pathway, such as members of the SOCS family have been implicated in prostate cancer (PCa) cell growth and survival. Although STAT3 involvement in PCa has been extensively studied, little is known about the role of STAT1. In this study, we aim to determine the clinical significance and functional role of STAT1 expression in PCa. Material and Methods. STAT1 cytoplasmic, nuclear and membrane expression in PCa epithelial cells, was measured by immunohistochemistry (IHC) on 78 patients with hormone naive prostate adenocarcinoma recruited at a referral centre between 1992 -2002. Biochemical relapse, survival from biochemical relapse and disease-specific survival according to high/low protein expression were analysed using Kaplan-Meier methods. Significant findings were included in a cox-regression model. Chi square test was used to assess associations with clinical parameters and Pearsons rank correlation coefficients (c.c) to assess association between protein expression. In in vitro studies we assessed the role of STAT1 in PCa epithelial cell (LNCaP and PC3) proliferation by wst-1 incorporation and real time tracking of growth of cells using XCELLigence (Roche, UK), apoptosis by DNA fragmentation and clonogenic capacity following transient silencing of STAT1 with siRNA (SmartPool, Dharmacon, UK). Results. At diagnosis PCa patients with low membrane expression of STAT1 had significantly shorter time to biochemical relapse (3.8 vs 7.3 years, p=0.021) and overall survival (6.62 vs 9.34 years, p=0.056). To test whether these results stemmed from the functional role of STAT1 in regulating the proliferation of prostate epithelial cells, we silenced STAT1 in PCa cell lines. STAT1 silencing resulted in a moderate increase in LNCaP cells (72h, control: 100 ± 18 %; siRNA STAT1 treated: 114 ± 4.5 %, n=3), however a very pronounced increase was observed in the proliferation of PC3 cells (72h, control: 100 ± 12.1 %; siRNA STAT1 treated: 177.4 ± 38 %, n=4, p<0.001). These results were in accordance with data collected from XCELLigence showing increased PC3 cell numbers in STAT1 silenced cells over 10 days. In clonogenic assay an increased surviving fraction of cells was recorded after 10 days of silecing the cells with STAT1 compared to control. Furthermore, there was no significant change in apoptosis recorded in siRNA STAT1 treated cells. Conclusion. Our results enable us to conclude that loss of STAT1 favors tumor formation in hormone naive PCa cells by leading to increased proliferation of PCa cells. We are currently investigating downstream transcription factors that STAT1 might employ in order to control the proliferation of PCa cells. Citation Format: Sophia Hatziieremia, Pamela McCall, Jennifer Willder, Clare Orange, Morag Seywright, Mark A. Underwood, Joanne Edwards. Loss of STAT1 predicts outcome in prostate cancer patients at diagnosis by regulating the proliferation of prostate epithelial cells. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1. doi:10.1158/1538-7445.AM2013-1

Identification of novel functional and spatial associations between sphingosine kinase 1, sphingosine 1‐phosphate receptors and other signaling proteins that affect prognostic outcome in estrogen receptor‐positive breast cancer

Sphingosine kinase is an enzyme that catalyses the phosphorylation of sphingosine to form sphingosine 1‐phosphate. Sphingosine 1‐phosphate is a bioactive lipid, which has been shown to have an important role in promoting the survival, growth and invasiveness of cancer cells. Sphingosine 1‐phosphate binds to five different plasma membrane sphingosine 1‐phosphate receptors (S1P1–5) and can regulate intracellular target proteins. We have used immunohistochemical analysis to determine the concurrent expression levels of sphingosine kinase 1 or S1P receptors and other signaling proteins in estrogen receptor‐positive breast cancer tumors and have then assessed the impact of these combinations on clinical outcome. This approach has enabled identification of (i) novel biomarkers and (ii) several spatially controlled associations between either sphingosine kinase 1 or S1P1–3 and other signaling proteins whose combination affect prognosis. For instance, the translocation of sphingosine kinase 1 to the plasma membrane has been shown to be a critical determinant in cancer progression. However, our findings identify an additional novel role for the nuclear localization of sphingosine kinase 1 combined with either ERK‐1/2 or SFK or LYN or AKT or NF‐κB, which significantly shortens disease‐specific survival and/or recurrence. We also demonstrate that nuclear S1P2 receptor and c‐SRC are associated with improved prognosis and this is linked with a reduction in the nuclear localization of sphingosine kinase 1. These findings identify potential novel biomarker associations, which might serve as new targets for drug intervention designed to improve treatment of estrogen receptor‐positive breast cancer.

Breast cancer outcomes by steroid hormone receptor status assessed visually and by computer image analysis

Mohammed Z M A, Edwards J, Orange C, Mallon E, Doughty J C, McMillan D C & Going J J 
(2012) Histopathology 61, 283–292