bluuebunny/crossref_metadata_2025_split huggingface dataset:
Notch and breast cancer: effects of a γ-secretase inhibitor on cell cycle.
Authors: Luraguiz NS , Yong TH , Sun AW 
Published: December 2010

Abstract
Abstract #3016
Background:&#x2028; Notch ligands and receptors are type I membrane proteins that regulate cell fate during cell-cell contact. Notch activation is oncogenic in many instances. Within the mammary gland, aberrant activation of the Notch pathway leads to adenocarcinoma. In human, high level of Notch1 expression in breast tumor is associated with reduced patient survival while better survival was observed where tumors expressed higher level of Notch2. In a recent report, it was observed that accumulation of Notch1 NICD increase Notch signaling in a wide variety of human breast carcinomas. Breast cancer is one of the most common malignancies in women with a cumulative lifetime risk of developing the disease as high as one in every eight women. Current research focused on treatment that disrupt the molecular mechanisms leading to breast carcinogenesis, which may be a more effective in treating breast cancer. GSI (g-secretase inhibitor) which blocks the activation of Notch is presently undergoing Phase I clinical trial conducted by Merck in breast cancer patients. We have investigated the different effects of GSI treatments on ER- and ER+ breast cancer cells and the results are discussed.&#x2028; Material and Methods:&#x2028; The human breast cancer cells lines MCF-7 and T47D (ER+), MDA-MB-435S and MDA-MB-231 (ER-) were treated with GSI, a Notch inhibitor, Tamoxifen, a selective estrogen receptor modulator (SERM) and combination of both drugs. Cell proliferation was determined by BrDU ELISA assay (Roche). Apoptosis following treatment was measured with TUNEL Assay Kit (Roche). The Cellular DNA Flow Cytometric Analysis Kit was used to determine the treatment on cell cycle. Trizol Reagent was use to extracted the RNA and Real Time PCR and RT Profiler PCR Array System were perform to detected the expression of genes.&#x2028; Results and Discussion:&#x2028; GSI alone is very effective on inhibiting the proliferation and promoting apoptosis of ER- cells but not ER+ cells. When combined with Tamoxifen, however, a significant killing effect was seen in ER+ cells. Cell cycle analysis revealed S phase block. The fold repression of Hes1 and Bcl2 was confirm after treatment with GSI in both cell lines. Together, these data strengthen the rationale for applying Notch inhibitors therapeutically. It also indicates the differences of the GSI treatment on ER+ vs ER- cells. In ER+ cells, both ER and Notch signaling pathways need to be targeted to effectively inhibit tumor cell growth and induce apoptosis. In ER- cells, targeting Notch signaling pathway is sufficient in achieving the same effects. The information will be critical when translating such research into clinic on deciding treatments for the breast cancer patients.
Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 3016.
Kruppel-like transcription factor 5 promotes breast cell survival through pERK-mediated MKP-1 protein stabilization.
Authors: Liu R , Zhou Z , Chen C 
Published: December 2010

Abstract
Abstract #3019
Kruppel-like Factor 5 (KLF5) is a transcription factor promoting cell survival and tumorigenesis in multiple cancers. High level of KLF5 mRNA is associated with a shorter survival for breast cancer patients. However, the role of KLF5 and mechanism of KLF5 actions in breast cancer remain unclear. In this study, we found that KLF5 knockdown by siRNA in two basal type breast cell lines MCF10A and BT20 induces apoptosis, as indicated by loss of cell viability and cleaved PARP and caspase 3. Interestingly, a survival phosphotase, MKP-1, is downregulated at protein level by KLF5 ablation. Consistently, KLF5 over-expression increases the MKP-1 protein expression. However, MKP-1 is not a KLF5 direct target gene because the MKP-1 mRNA level is not regulated by KLF5. By the cycloheximide chase assays, we found that KLF5 decreases the MKP-1 protein degradation. However, KLF5 does not decrease the MKP-1 E3 ubiquitin ligase SKP2 expression. The ERK inhibitor U0126 specifically blocks the KLF5 induced MKP-1, suggesting that KLF5 up-regulates MKP-1 through activating ERK signaling. Finally, we demonstrated that MKP-1 over-expression blocks KLF5 knockdown induced apoptosis in MCF10A cells. These findings suggest that KLF5 is a survival factor which promotes breast cell survival partially through pERK-mediated MKP-1 stabilization. The KLF5-pERK-MKP-1 signaling axis may provide new therapeutic targets for invasive breast cancer.
Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 3019.
Activated c-Src (Y215) kinase expression predicts for early relapse on tamoxifen in human breast cancer.
Authors: Tovey SM , Tan BA , Campbell J , Elsberger B , Brunton V , Mallon E , Cooke TC , Edwards J 
Published: December 2010

Abstract
Abstract #3025
Recent studies have demonstrated activation of the non-receptor tyrosine kinase c-Src in tamoxifen resistant breast cancer cell lines, which when treated with Src inhibitors demonstrate a reduction in motility and invasiveness. However, there are little published translational studies confirming a role for c-Src in tamoxifen resistance in vivo. We aim to determine if activated c-Src expression correlates clinically with increased recurrence on tamoxifen.&#x2028; Methods&#x2028; Tissue microarrays were constructed from a patient cohort of 402 Tamoxifen treated ER positive patients. Immunohistochemistry was performed using commercially available antibodies to Total Src as well as to activated (phosphorylated) c-Src at 2 sites (Y416 and Y215) (pSrc416 and pSrc215 respectively). Expression was assessed by 2 independent scorers (weighted histoscore method). HER1-3 status and expression of membranous phosphorylated ER (sites serine 118 and 167) had previously been determined. All statistical calculations were performed using SPSS 15, including Kaplan-Meier life table analysis with log rank testing of differences in breast cancer related relapse whilst on tamoxifen.&#x2028; Results&#x2028; Membranous pSrc215 was observed in 20.3% of the cases but was more frequently observed in the cytoplasm (85.9%) and nucleus (90.5%). Overexpression of cytoplasmic pSrc215 was associated with an earlier time to recurrence (p = 0.037).&#x2028; &#x2028; Cox regression analysis confirmed this to be independent of grade, nodal and HER1-3 status (p=0.028, HR 3.17 (1.14–8.85)). Cytoplasmic pSrc215 was also strongly correlated with membranous phospho-ER, EGFR and HER3 status (Mann Whitney; p&lt;0.001, p=0.026, p&lt;0.001 respectively). Membranous and nuclear pSrc215 staining were not associated with time to relapse.&#x2028; Over expression of Total Src and pSrc416 did not predict for relapse.&#x2028; Discussion&#x2028; Our findings provide support to in vitro studies linking c-Src with tamoxifen resistance. The phosphorylation site pSrc215 is a putative site of activation by HER2 and PGFR resulting in up to 50 fold activation of Src in vitro. The correlations demonstrated with HER status and membranous ER lead us to speculate that this interplay between non genomic ER and Src activation may provide a mechanism for the lack of response to tamoxifen in these patients.&#x2028; Further studies are required to determine if activated pSrc215 represents activated c-Src alone or may also represent activation of other Src family members as the Y416 and Y215 sequences are highly conserved amongst the Src kinases with homologous activation sites. If confirmed, future use of novel combination therapies with Src inhibitors may have an important role in combating tamoxifen resistance.
Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 3025.
Lapatinib can activate or supress estrogen receptor (ER) signaling in cell models of endocrine resistant breast cancer.
Authors: Leary AF , Martin L , Lykkesfeldt AE , Dowsett M , Johnston SR 
Published: December 2010

Abstract
Abstract #3031
Background&#x2028; Growth factor (GF) signaling is frequently upregulated in hormone resistant breast cancer (BC) and provides the rationale for using the dual EGFR/HER2 inhibitor, lapatinib (LAP) in an effort to overcome endocrine resistance. Hormone resistant BC can also vary in its degree of continued ER dependence. We previously demonstrated potent synergy between LAP and TAM in cell models of acquired endocrine resistance to tamoxifen (TAMR cells), and to estrogen deprivation (LTED cells)1. This study aimed to characterize the phenotype of these two models with a focus on the ER pathway, and to determine the biological basis for the observed synergy between LAP and TAM.&#x2028; Methods&#x2028; LTED cells and TAMR cells were both derived from hormone-sensitive MCF7 parental cells as previously described1. The differential effects of LAP, TAM, estrogen deprivation (ED) or the combination were assessed by proliferation assays, ERE reporter assays, quantitative PCR and western blot analyses.&#x2028; Results&#x2028; In LTEDs: Increased ER expression and ERE transactivation were seen in LTEDs compared to MCF7 cells, as well as continued sensitivity to the ER downregulator, fulvestrant (FUL), indicating that in LTEDs, ER activity is not only enhanced but is also a significant driver of growth. In LTEDs, LAP alone suppressed ER activity as measured by both ERE transactivation and ER phosphorylation at Ser118; the most effective suppression of ER activity was achieved with a combination of LAP+TAM/ED where the effects were additive.&#x2028; In TAMRs: In contrast, TAMRs demonstrated decreased ER activity (low basal ERE transactivation and loss of PgR) and ER independent proliferation (FUL had minimal growth inhibitory effects despite ER downregulation). In TAMRs, neither LAP nor TAM had significant antiproliferative effects on their own: LAP alone decreased pMAPK/pAkt but increased basal ERE transactivation and transcription of the ER-responsive gene pS2. TAM alone inhibited ERE activation but increased HER2 gene and protein expression. Inhibiting both HER2 and ER pathways with LAP+TAM resulted in synergistic growth inhibition.&#x2028; Conclusions&#x2028; In LTED cells with enhanced ER function attributable in part to GF receptor activation, the synergistic antiproliferative effects from LAP and TAM or ED may be largely due to enhanced inhibition of ER signaling. In contrast in TAMR cells with suppressed ER activity, LAP alone appears to enhance ER signaling, while TAM alone inhibits ER activity but increases HER2 expression. In TAMRs, the combination of TAM+LAP is required to interrupt both ER and GF signaling. These results suggest that the basis for synergy between LAP and endocrine therapy in hormone resistant BC may vary depending on the nature of the cross-talk between the ER and GF pathways.&#x2028; 1SABCS, 2006 Abs 303.
Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 3031.
Association of the polymorphisms CYP19 (TTTA)n in treatment response to hormone therapy based in aromatase inhibitors in breast cancer patients.
Authors: Murillo-Ortiz B , Castillo-Valenzuela R , Martínez-Garza S , Moreno-Perez A , Silva A , Ruiz-García E , Astudillo-de la Vega H 
Published: December 2010

Abstract
Abstract #3033
Background &#x2028; Case-control studies have reported inconsistent results concerning breast cancer risk and polymorphisms in genes that control endogenous estrogen biosynthesis. We report findings from the first study in Mexican women examining associations between female with breast cancer and polymorphisms CYP19 (TTTA repeated polymorphism).&#x2028; Methods &#x2028; We conducted a study among 180 healthy women and 70 women with breast cancer underwent hormone therapy with aromatase inhibitor. DNA and questionnaire data was obtained. Tandem repeated (TTTA)n polymorphism in CYP19 gene was determined by PCR followed by electrophoresis on denaturalizing acrilamide gel stained with silver nitrate. Differences were visualized with Gel-Doc BioRad. Estrone, estradiol and FSH levels were measured by RIA and IRMA. We used likelihood-based statistical methods to examine allelic associations.&#x2028; Results:&#x2028; 250 women (age 55 ± 12 years) were included. BMI was 30 ± 7.1 Kg/m2. We found a distribution of different CYP19 allele frequencies. In healthy women the allele frequencies with 6 (32.7 %) and 7 (21.6 %) tandem repetitions were the most frequent, in women with breast cancer the alleles with 6(29%) and 10(26%) tandem repeated were the most frequent. A relationship between hormonal levels and number of (TTTA) repeated was not found. Anastrozol reduced significantly estrona and estradiol. Surpriseling we found in a patients with 10 or more (TTTA)n repeated an association with a mayor tumoral activity (p=0.04).&#x2028; Conclusion &#x2028; This study indicates that status of CYP19 &gt;10 TTTA repeated might be related to increased breast cancer risk and with the clinical response (aromatase inhibitor). Because of this is the first study to report an association between CYP19 &gt;10 TTTA repeated and treatment hormonal response in breast cancer.
Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 3033.
The developmental protein HOXc11 as a mediator of endocrine resistance in breast cancer.
Authors: McCartan DP , McIlroy M , Eary S , Hill AD , Young LS 
Published: December 2010

Abstract
Abstract #3034
The nuclear receptor coactivator, SRC-1, has been implicated as an important mediator of resistance to endocrine therapy in breast cancer through work from our group and others. Using mass spectrometry we identified the homeobox protein HOXc11 as an interacting partner for the nuclear receptor coactivator SRC-1 in endocrine resistant breast cancer cells. Homeobox genes control cell differentiation. The processes of neoplasia and normal development are closely linked, therefore it is little surprise that increasing evidence implicates these genes in neoplasia development.&#x2028; We propose that the interaction between SRC-1 and HOXc11 plays an important role in the development of endocrine resistance. Our aim was to identify potential HOXc11/SRC-1 target genes and assess the clinical significance of these genes.&#x2028; Co-immunprecipitation assays confirmed the SRC-1 and HOXc11 interaction after treatment with tamoxifen for 2 hours in the endocrine resistant LY2 breast cancer cell line, an interaction that was not present in endocrine sensitive MCF-7 cells under the same treatment conditions. A target gene for HOXc11, S100β, has previously been identified in neuronal cells. Based on this we sought the presence of either protein at the promoter region for S100β. Chromatin immunoprecipitation (ChIP) assays in LY2 cells confirmed recruitment of both HOXc11 and SRC-1 to the promoter region of S100β after treatment with tamoxifen at both 45 minutes and 2 hours when compared to control.&#x2028; To assess the clinical significance of S100β, we used immunohistochemistry on a paraffin embedded tissue microarray to examine itÂs expression in a large cohort of breast cancer patients (n=560). S100β was a strong predictor of reduced disease free survival in patients receiving adjuvant endocrine treatment (Hazard ratio 5.82; p&lt;0.0001). This also showed that expression of S100β was associated with expression of HOXc11 and SRC-1. Given that S100β is a secreted protein, we hypothesized that elevated levels could be detected in patients with breast cancer at time of diagnosis. Using an ELISA to measure S100β levels, we found elevated levels in one quarter of breast cancer patients, pre treatment, when compared to age matched controls.&#x2028; Investigation into non steroidal SRC-1 binding partners in endocrine resistant breast cancer identified the homeobox protein HOXc11. A target gene for the interaction between SRC-1 and HOXc11, S100β, is a secreted protein and raises the exciting possibility that it may offer potential as a biomarker for endocrine resistance in breast cancer.
Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 3034.
Novel non-steroidal p160 coactivator interactions in tamoxifen resistant breast cancer.
Authors: McIlroy M , McCartan D , Early S , Hill AD , Young LS 
Published: December 2010

Abstract
Abstract #3038
While most breast cancer patients initially respond to endocrine therapy, 30-40% of cases relapse within 5 years of treatment. Translational studies from our group and others have provided substantial evidence of a significant role for p160 family of Steroid Receptor Co-activator (SRC) proteins in the development of resistance to endocrine therapy. In this study we have investigated novel non-steroidal SRC-1 interactions in endocrine resistant breast cancer.&#x2028; A mass-spectrometry-based screen was used to identify proteins which differentially interact with SRC-1 in endocrine resistant compared with endocrine sensitive breast cancer cells. The developmental protein, HOXC11, was confirmed as an SRC-1 interacting partner. HOXC11 was shown to be over-expressed in tamoxifen-resistant cells using immunocytochemistry and was observed to translocate to the nucleus and peri-nuclear region when cells were treated with tamoxifen. In a breast cancer TMA (n=560) HOXC11 was found to correlate with disease recurrence and metastasis (local and distant). Moreover, in addition to associating with SRC-1, HOXC11 was found to be a strong predictor of reduced disease-free survival on endocrine treatment (Hazard ratio: 5.79; p&lt;0.0001).&#x2028; Bioinformatic analysis identified S100β as a target gene of the HOXC11 transcription factor. Interestingly, the s100 family of calcium binding proteins has been associated with poor outcome and reduced disease-free survival in melanoma. Reporter assays were used to confirm HOXC11 as a mediator of S100β transcription. Regulation of the target gene in the presence of tamoxifen was shown to be modified by activation of protein kinase A (PKA) which has previously been implicated in the enhancement of tamoxifenÂs agonist profile. Here we have defined HOXC11 as a non-steroidal interacting partner of SRC-1; furthermore, this interaction appears to be regulated by the activation of PKA. HOXC11 expression in our breast cancer patient cohort associated with poor survival and the development of metastatic disease. This study provides evidence of a novel mechanism at play in endocrine resistant breast cancer cells.
Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 3038.
Persistence of isolated tumor cells in the bone marrow of breast cancer patients predicts increased risk for relapse – a European pooled analysis.
Authors: Naume B , Fehm T , Wiedswang G , Jückstock J , Borgen E , Rack B , Synnestvedt M , Braun S , Sommer H , Solomayer E , Pantel K , Friese K , Janni W 
Published: December 2010

Abstract
Abstract #304
Purpose:&#x2028; The prognostic significance of DTC in the BM of breast cancer pts at the time of primary diagnosis has already been confirmed by a large pooled analysis. In view of the lack of early indicators for secondary adjuvant treatment, we here evaluated whether the persistence of DTC after adjuvant therapy confers a risk for relapse and breast cancer-related death.&#x2028; Patients and Methods:&#x2028; We analyzed BM aspirates of 723 pts from academic breast cancer units in Oslo (n=356), Munich (n=228) and Tuebingen (n=139) during recurrence-free follow-up at a mean interval of 31.7 months (standard deviation [std] 19.4 months) after primary diagnosis of breast cancer pT1-4, pN0-3 pM0. Carcinoma cells were detected using a standardized immunoassay with the monoclonal antibodies A45-B/B3 (Munich, Tuebingen), or AE1 and AE3 (Oslo), directed against cytokeratin (CK). Pts were followed for a median of 54.5 months (SD 25.1 months) after primary diagnosis.&#x2028; Results:&#x2028; Persistent DTC in the BM was detected in 15.5% of the pts (n=112). The Kaplan-Meier estimate for mean distant relapse-free survival was 162.5 months (157.9 – 167.0 95%CI) in pts with negative and 102.4 months (94.2 – 110.6, 95% CI, p&lt; .0001, log rank test) in pts with positive BM status. The mean overall survival was 170.1 months, (167.7 – 172.5 95% CI), compared to 113.4 months in patients with persistent DTC in BM (107.3 – 119.5, p &lt; .0001). In multivariate Cox regression analysis, allowing for BM status, tumor size, nodal status and histopathological grading, presence of DTC was an independent prognostic factor for reduced breast cancer specific survival ((RR 3.42, 1.64 – 7.13 95% CI, p= .001).&#x2028; Conclusion:&#x2028; Persistent DTC significantly predicts an increased risk for subsequent relapse, and, therefore, might serve as a potent monitoring tool for the follow-up of breast cancer pts. Future therapeutic intervention trials are currently being initiated to assess the benefit of secondary adjuvant treatment based on DTC detection as stratification parameter.
Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 304.
Outcomes of triple negative breast cancer in African-Americans vs. Caucasians: a community-based study.
Authors: Shah MM , Patel JK , Fischbach NA 
Published: December 2010

Abstract
Abstract #3043
Background: Breast cancers with a triple negative tumor (TNT) subtype are associated with inferior outcomes and more recently racial disparities in patients with TNT have been demonstrated with African American women experiencing worse outcomes compared to Caucasians. This study examines association of race (AA vs. Caucasians) and breast cancer outcomes in a large community hospital TNT population.&#x2028; Methods: Breast cancers of the TNT subtype were reviewed from a hospital-based tumor registry. Cases diagnosed from 1999 to 2006 were included in the study. Multivariate regression analyses were conducted including socio-demographic, and treatment factors. Endpoints were local/systemic recurrence and death.&#x2028; Results: Of 1827 newly diagnosed cases of breast cancer from 1999- 2006, 93 were of the TNT subtype. A higher number of AA (17.58%) had TNT compared to Caucasians (3.7%). In patients with TNT, AA presented at a younger age (mean age 51.78 years vs. 58.52 years, (&lt;50 years) (p value=0.07), had more advanced disease at diagnosis (stage 3) (5.38% vs. 1.08%; p value 0.001) and had a poor insurance status (uninsured and Medicaid) (9.68% vs. 4.30%; p value 0.004). There was no difference in the histologic grade of the tumors. AA had a higher rate of local recurrence (4.30% vs. 2.15%; p value 0.029), systemic recurrence (19% vs. 10%; p value 0.02) [Figure 2] and death (17.20% vs. 13.98%; p value 0.005) [Figure 1] compared to Caucasians.&#x2028; &#x2028; &#x2028; &#x2028; Even after adjusting for insurance status and treatment modalities, AA had a higher mortality rate compared to Caucasians (p value 0.014).&#x2028; Conclusions: The high prevalence of TNTs among AA women and poorer survival in spite of adjusting for insurance and treatment modalities, suggests an underlying biologic variation with respect to race/ ethnicity.
Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 3043.