bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract P6-01-05: Enhancement of18F-FDG uptake and glycolysis by epidermal growth factor via PI3K activation in T47D breast cancer cells
Authors: Lee EJ , Park JW , Cung Q , Jung K-H , Lee JH , Paik J-Y , Lee K-H 
Published: August 2014

Abstract
It is well known that the binding of epidermal growth factor (EGF) to EGF receptors (EGFR) stimulates proliferation of breast cancer cells via activation of mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3-kinase (PI3K)-protein kinase B (Akt) signaling pathways. There was a report that glucose consumption and lactate production were increased in MDA-MB-468 breast cancer cells following EGF exposure. However, the effect of EGF in enhancing glucose uptake and signaling pathways that are involved have not been clearly revealed. We thus investigated the role of EGF in stimulation of18F-FDG uptake in T47D breast cancer cells, and further elucidated the molecular mechanisms that are involved.
Exposure of T47D cells to 100 ng/mL EGF for 24 h caused a substantial augmentation of18F-FDG uptake to even greater extents to 310.8% ± 30.1% of control cells (P &lt; 0.001), and this effect of EGF showed dose- and time-dependency. Increased glucose uptake by EGF occurred through enhanced membrane GLUT-1 expression as well as hexokinase activity. Inhibition experiments with cycloheximide showed that the metabolic effect by EGF required new protein biosynthesis. Stimulation of glucose uptake by EGF was dependent on sufficient EGFR expression because18F-FDG uptake in MCF-7 cells weakly expressing EGFR was not affected by EGF treatment. Although EGF was also a stimulator of T47D cell proliferation (137.3 ± 7.3% of basal levels at 24 h, P &lt; 0.001), the metabolic effect occurred in a manner that clearly preceded and surpassed the proliferative effect. EGF-stimulated proliferation was significantly inhibited by the EGFR inhibitor BIBX1382, the PI3K inhibitor LY294002 and the specific MAPK inhibitor PD98059. Unlike proliferation, the ability of EGF to augment18F-FDG uptake was found to be dependent on PI3K but not on MAPK activity.
These findings yield the insight into our understanding of the role of EGF and the molecular basis that are involved in glucose metabolism of breast cancer cells.
Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P6-01-05.
Abstract P6-02-08: Molecular drivers of adipogenotoxicosis in breast tumor-associated adipose
Authors: Ellsworth RE , Field LA , van Laar R , Deyarmin B , Hooke JA , Shriver CD 
Published: August 2014

Abstract
Background: Having long been thought to function only as an inert energy storage depot, the role of adipose tissue in tumorigenesis has been largely ignored; however, adipose is an active endocrine organ that can directly influence tumor growth. Improved understanding of the role of adipose in tumorigenesis is crucial given the association between obesity and breast cancer risk in post-menopausal women, increasing rates of obesity and use of autologous fat transfer in breast reconstruction.
Methods: Adipose, adjacent to and distant from (&gt;3 cm from the closest tumor margin) invasive breast tumors, was laser microdissected from 20 post-menopausal women, and from 22 post-menopausal women with non-malignant breast disease. Gene expression data were generated using U133A 2.0 microarrays. Data were analyzed to identify significant patterns of differential expression between adipose classes at the individual gene and molecular pathway level. Gene expression differences were validated using qRT-PCR in an additional set of 29 specimens.
Results: SPP1, RRM2, MMP9 and PLA2G7 were expressed at &gt;3-fold (P &lt; 0.01) higher levels in adjacent adipose compared to distant adipose from the same breast. A number of immune response genes including MARCO, FABP7, ELF5, MYBPC1, MMP7, CLDN8, HLA-DQB1 and HLA-DQA1 were differentially expressed in distant adipose compared to adipose from non-malignant breasts. The most significant gene expression differences were detected between tumor-adjacent and non-malignant adipose with &gt;3-fold higher expression of EGFL6 and ITGB2 and &gt;3-fold lower levels of PIP, which are involved in growth, proliferation, and cellular adhesion in adjacent compared to non-malignant adipose. Pathway analysis revealed that immune response differs between non-malignant, distant and tumor-adjacent adipose with an enhanced B- and T-cell response detected in adjacent compared to distant or non-malignant adipose. Inflammatory response as well as DNA transcription and replication pathways were differentially expressed in distant compared to non-malignant adipose.
Conclusions: Gene expression levels differ in breast adipose depending on presence of and proximity to tumor cells. Adipose adjacent to the tumor demonstrated the largest immune response, supporting the idea of adipogenotoxicosis, which through pro-inflammatory and genotoxic responses, promotes tumor development. In addition, genes involved in cellular proliferation, degradation of the extracellular matrix and angiogenesis are differentially expressed in adjacent compared to distant or non-malignant adipose, thus tumor-adjacent adipose may be contributing to the growth and invasion of the primary tumor. These data thus suggest that adipose is not an inert component of the breast microenvironment but plays an active role in tumorigenesis.
Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P6-02-08.
Abstract P6-02-09: Role of HGF in obesity-associated tumorigenesis: C3(1)-Tag mice as a model for human basal-like breast cancer
Authors: Sundaram S , Freemerman AJ , Hamilton J , McNaughton K , Galanko JA , Darr DB , Perou CM , Troester MA , Makowski L 
Published: August 2014

Abstract
Obesity is associated with basal-like breast cancer (BBC), an aggressive breast cancer subtype. The objective of this study was to determine whether high fat diet-induced obesity promotes BBC onset in adulthood and to evaluate the role of stromal-epithelial interactions in obesity-associated tumorigenesis. Specifically, we hypothesized that hepatocyte growth factor (HGF) plays a promoting role in BBC, which tends to express the HGF receptor, c-Met. In C3(1)-Tag mice, a murine model of BBC, we demonstrate that obesity leads to a significant increase in HGF secretion and an associated decrease in tumor latency. By immunohistochemical analysis, normal mammary tissue exhibit obesity-induced hepatocyte growth factor (HGF) in stroma and corresponding epithelial expression of c-Met. HGF secretion was also increased in primary mammary fibroblasts isolated from normal mammary and tumors of obese mice compared to lean. These results show that diet-induced elevation of HGF expression is a stable phenotype, maintained after several passages and after removal of dietary stimulation. In cocultures, neutralization of HGF blunted tumor cell migration; further linking diet-mediated HGF-dependent effects in tumor aggressiveness. In sum, these results suggest that HGF plays an important role in obesity-associated carcinogenesis and raise the hypothesis that diet may affect lasting changes in stroma, potentially through epigenetic means. Understanding the effects of obesity on risk and progression is important given epidemiologic studies that imply half of BBC could be eliminated by reducing obesity. Our findings suggest the possibility that reducing obesity may be useful in preventing obesity-associated breast cancer mediated by the HGF/c-Met pathway.
Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P6-02-09.
Abstract P6-04-02: Final progression-free survival analysis of BOLERO-2: a phase III trial of everolimus for postmenopausal women with advanced breast cancer
Authors: Piccart M , Baselga J , Noguchi S , Burris H , Gnant M , Hortobagyi G , Mukhopadhyay P , Taran T , Sahmoud T , Rugo H 
Published: August 2014

Abstract
Introduction: Treatment options for postmenopausal women with hormone receptor-positive (HR+) breast cancer (BC) who relapse or progress on a nonsteroidal aromatase inhibitor (NSAI) are limited. Interim analyses of the BOLERO-2 trial demonstrated that combining the oral mammalian target of rapamycin (mTOR) inhibitor, everolimus (EVE), with the steroidal aromatase inhibitor, exemestane (EXE), significantly prolonged progression-free survival (PFS) in this patient population. Protocol-specified final PFS analyses are presented.
Methods: The phase III, double-blind, BOLERO-2 trial randomized postmenopausal women with HR+ BC progressing or recurring after NSAIs to EVE (10 mg once daily; n = 485) plus EXE (25 mg once daily) or placebo (PBO; n = 239) plus EXE. The primary endpoint was PFS. Secondary endpoints included overall survival, safety, bone turnover, and overall response rate.
Results: At a median follow-up of 18 months, 510 PFS events were reported. The addition of EVE to EXE significantly prolonged median PFS versus EXE monotherapy as per local assessment (7.8 vs 3.2 mo, respectively; HR = 0.45 [95% CI, 0.38–0.54]; log-rank P &lt; .0001). Furthermore, these data were consistent with results based on central assessment (11.0 mo for EVE + EXE vs 4.1 mo for EXE alone; HR = 0.38 [95% CI, 0.31–0.48]; log-rank P &lt; .0001). Fewer deaths were reported with EVE + EXE (25.4%) vs PBO + EXE (32.2%). In addition to significantly improving PFS and delaying disease progression in bone, PFS benefits with EVE + EXE versus PBO + EXE were consistent in all prospectively defined subgroups, including subsets of patients with visceral metastases (n = 406), 3 or more sites of metastasis (n = 271), and Eastern Cooperative Oncology Group (ECOG) performance status 1 or 2 (n = 274). The safety profile of EVE + EXE was consistent with that reported at the interim analysis and with data for EVE from other oncology settings. Updated overall survival data will be presented.
Conclusions: Adding EVE to EXE markedly prolonged PFS in the overall population and in all patient subsets, validating the rationale of targeting the mTOR pathway to improve clinical outcome in patients with HR+ advanced BC progressing during or after NSAI therapy.
Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P6-04-02.
Abstract P6-04-03: Changes in breast tumor metabolism and estradiol binding as measured by FES PET in patients treated with the histone deacetylace inhibitor vorinostat and aromatase inhibitor therapy
Authors: Linden HM , Kurland BF , Specht JM , Vijayakrishn GK , Gralow JR , Peterson LM , Schubert EK , Link JM , David MA , Eary JF , Krohn KA 
Published: August 2014

Abstract
Background: Some estrogen receptor-positive (ER+) metastatic breast cancers are bone and soft tissue dominant, indolent, and controlled by endocrine therapy. However, these tumors eventually become refractory to endocrine therapy and need a mechanism to reset the “estrogen-dependence” to allow continued benefit upon progression. Histone deacetylase inhibitors (HDACi) act as modulators of gene expression that are promising therapeutic agents for this group of tumors (Huang 2000, Sabnis 2011). Preclinical and clinical data demonstrate in ER-poor tumors and cell lines ER up-regulation and consequently enhanced lethality to endocrine agents. The optimal dose and schedule are not known, but two promising phase II studies show benefit in a continuous schedule (Yardley 2011, Munster 2011). FES PET is a promising imaging agent used as a biomarker to determine which patients will benefit from endocrine therapy, and to monitor estradiol binding during therapy (Mortimer 2001, Linden 2011).
Methods: Patients with ER+ HER2− metastatic breast cancer with prior aromatase inhibitor (AI) exposure and clinical benefit of endocrine therapy were eligible for a phase II study of HDACi therapy to restore sensitivity to AI therapy. Following baseline FDG PET, FES PET and standard imaging (CT, MRI, ultrasound and/or bone scan as indicated by tumor location), patients received 2 weeks of vorinostat therapy (400 mg po daily). FES PET was performed at 2 weeks while on HDACi therapy. Patients then received 6 weeks of AI monotherapy. FDG PET, FES PET and response assessment were performed at 8 weeks. Patients with clinical benefit (stable disease or response) continued on the regimen, 2 weeks of vorinostat followed by 6 weeks of AI.
Results: To date, 8 patients have been enrolled of whom 6 have completed the first 8 weeks of treatment and all correlative imaging studies. FES biomarker imaging results are mixed, with some patients showing an increase in tumor estradiol concentrating ability by FES PET on HDACi therapy, and decline in metabolic activity by FDG. Two patients continue on treatment with clinical benefit. Results will be updated as accrual continues.
Conclusions: Changes in estradiol binding are measured by serial FES PET in patients on HDACi therapy support preclinical concept of HDACi modulation of ER expression in metastatic breast cancer. Molecular imaging is a promising tool to monitor Estradiol binding pharmacodynamics, and Vorinostat HDACi therapy is a promising novel approach to allow patients to avoid toxicities of traditional chemotherapy once their tumor has progressed on endocrine therapy.
Funding: P01, MKA, Merck
Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P6-04-03.
Abstract P6-04-11: Combination of PI3K-AKT-mTOR and MEK-ERK pathway inhibitors overcome acquired resistance to letrozole in ER+ breast cancer models
Authors: De P , Sun Y , Friedman LS , Chen S , Dey N , Leyland-Jones B 
Published: August 2014

Abstract
Background: Approximately 60–70% of breast cancers (BC) express estrogen receptor (ERα) and/or progesterone receptor (PR), the most common malignancy in women in the US and Europe. Many though not all patients with ER+ BC respond to hormonal therapy (e.g. tamoxifen and aromatase-inhibitor) but a large number will eventually develop resistance to long term therapy.
Purpose: Development of resistance to endocrine therapy is a clinical issue in ER+ BC. Studies with human cell lines have shown that upregulation of PI3K-AKT-mTOR and MEK-ERK pathways contributes to resistance to endocrine therapy (Miller TW et al JCO 2011; Sanchez CG et al Breast Cancer Res 2011). Using leterozole-resistant ER+ BC model, we investigated the effects of PI3K-AKT-mTOR pathway inhibitor alone and in combination with MEK1/2 inhibitor.
Methodology: The anti-proliferative, anti-migratory, and intracellular signaling (pAKT, pS6RP, p4EBP1 and pERK) effects of GDC-0941 (Class I PI3K inhibitor) or GDC-0980 (dual PI3K/mTOR inhibitor) alone and in combination with GDC-0973 (MEK1/2 inhibitor) were evaluated in aromatase overexpressed (MCF-7aro), letrozole-resistant (MCF-7aro/LetR) and long-term-estrogen-deprived (LTEDaro) BC cell lines by MTT assays, integrin-mediated migration assay and Western blots.
Results: 1) Both GDC-0980 and GDC-0941 exhibited excellent in vitro cell killing activity in MTT assay in all cell lines with IC50's 10–30 nM & 0.2–1.5 µM respectively. PI3K pathway inhibitors were more potent when combined with GDC-0973; 2) Integrin-mediated migration was significantly higher in both MCF-7aro/LetR andLTEDaro cells than MCF-7 and MCF-7aro cells; 3) Both MCF-7aro/LetR and LTEDaro cells movement were significantly abrogated following the treatment of GDC-0980, and the combination of GDC-0980 plus GDC-0973 more effectively blocked integrin-mediated migration; 4) Inhibition of phosphorylation of AKT (S473/T308), S6RP and 4EBP1 (T37/46) was observed following PI3K pathway inhibitors; 5) pERK was upregulated following the treatment of GDC-0941 (PI3K inhibitor); 6) Basal level of pERK was significantly high in MCF7/LetR and MCF7/LTED cells, and GDC-0980 failed to change the level of pERK in those cell lines; and 7) Combination of PI3K pathway inhibitor plus MEK1/2 inhibitor significantly blocked activation of both pathways.
Conclusion: Our in vitro data suggest that therapeutic targeting of the PI3K-AKT-mTOR and the MEK-ERK signaling pathways should be effective in abrogating aromatase-inhibitor-resistance in ER+ BC.
Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P6-04-11.
Abstract P6-04-18: Evaluation of the molecular mechanisms behind fulvestrant resistant breast cancer
Authors: Kirkegaard T , Hansen SK , Reiter BE , Sorensen BS , Lykkesfeldt AE 
Published: August 2014

Abstract
To study the mechanisms behind treatment resistance, we have previously established a large panel of antiestrogen resistant breast cancer cell lines based on the estrogen receptor (ER)-positive breast cancer cell line, MCF-7. It seems to be a general phenomenon that MCF-7 cells switch from ER driven to human epidermal growth factor receptor (HER) driven cell growth upon development of fulvestrant resistance. To obtain a broader knowledge of the resistance mechanisms, we have established four fulvestrant resistant subclones from the ER-positive breast cancer cell line, T47D.
The parental T47D cells were confirmed to be estrogen responsive and short-term treatment of the parental T47D cells with fulvestrant severely reduced cell growth as well as protein expression of ER and the estrogen regulated proteins, insulin-like growth factor 1 receptor alpha (IGF-1Rα) and progesterone receptor (PR). All four fulvestrant resistant cell lines had reduced mRNA and protein expression of HER1 and HER4 compared to T47D, while HER2 was highly up regulated in the fulvestrant resistant cell lines and ER was lost. No difference in response to the HER2 inhibitor trastuzumab or the specific HER2 kinase inhibitor AG825 was observed between the fulvestrant resistant cell lines and T47D, indicating that HER2 is not the main driver of fulvestrant resistance in T47D cells. We found no indication of involvement of the two classical signaling pathways downstream of the HER receptors (Ras/Raf/Erk and PI3K/Akt). However, the JNK inhibitor SP600125 preferentially inhibited growth of two tested fulvestrant resistant cell lines. Withdrawal of fulvestrant for several weeks did not result in regain of ER expression, or in change of HER receptor expression, supporting a stable resistant phenotype.
In conclusion, loss of ER expression explains the lack of effect of fulvestrant in the T47D fulvestrant resistant cell lines. Noteworthy, the observed over expression of HER2 in the fulvestrant resistant T47D cells does not seem to be the main driver of cell growth, as HER2 targeted therapies like trastuzumab and HER2 kinase inhibitor did not exert a preferential growth inhibition of resistant cells. These breast cancer cells with high endogenous HER2 expression will be used as a model mimicking HER2 positive breast cancer which does not respond to standard HER2 targeted therapies.
Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P6-04-18.
Abstract P6-04-22: Regulation of Notch localization by endocrine therapy in Estrogen Receptor positive breast cancer cells: Clinical implications for endocrine resistance
Authors: Espinoza I , Caskey M , Baker RC , Miele L 
Published: August 2014

Abstract
Background: Estrogen receptors occur in about two-thirds of breast tumors and endocrine therapy is probably the most important systemic therapy for hormone receptor positive breast cancer. However, after an initial response to hormonal therapy, most tumors develop resistance leading to disease progression. Central mechanisms thought to be involved in this process include: 1) alterations in tumor cell physiology causing insensitivity to drug-induced apoptosis or induction of drug-detoxifying mechanisms; 2) expression of energy-dependent transporters that eject anti-cancer drugs from cells and 3) the emergence of cancer stem-like cell clones that are estrogen-independent and/or antiestrogen resistant. We and others have shown that Notch signaling mediates survival signals in ER+ breast cancer cells; induces expression of drug transporter ABCG2 (BCRP), activates ERα in the absence of estrogen and mediates survival of breast cancer stem-like cells. Previously, we demonstrated a crosstalk between ERα and Notch signaling whereby estrogen inhibits Notch activation and estrogen withdrawal or tamoxifen re-activate Notch, a possible mechanism of resistance. The mechanism of these effects has remained elusive.
Methods: we used sub-cellular fractionation and immunofluorescence staining to investigate the total expression and cellular distribution of Notch signaling components in MCF-7 cells treated with 17-β-estradiol, or estrogen-free medium.
Results: Our data shows that in cells treated with estrogen-free medium, Notch1 is located in the Lipid Rafts (LR) in the plasma membrane, along with Notch signaling components such as presenilin 1 (the catalytic subunit of γ-secretase), ADAM10 and Notch negative regulator NUMB. There is published evidence that γ-secretase is most active in lipid rafts.17-β-Estradiol modifies the membrane lipid composition and change the localization of Notch and Notch regulators (such as ADAM10, presenilin-1 and NUMB) at the plasma membrane, thereby altering the activation of Notch. These observations are consistent with a model in which the lipid composition of the plasma membrane is a critical factor in regulating the rate of Notch activation. FDA-approved cholesterol lowering drugs affect Notch signaling in ways consistent with this model.
Conclusions: Our findings indicate that endocrine therapy affects Notch signaling at least in part through alterations in membrane composition and lipid raft localization of Notch signaling components.
Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P6-04-22.