Treatment Of Breast Cancer Brain Metastases Research Articles

Protecting the Brain: Novel Strategies for Preventing Breast Cancer Brain Metastases through Selective Estrogen Receptor β Agonists and In Vitro Blood-Brain Barrier Models.

Breast cancer brain metastasis (BCBM) is a challenging condition with limited treatment options and poor prognosis. Understanding the interactions between tumor cells and the blood-brain barrier (BBB) is critical for developing novel therapeutic strategies. One promising target is estrogen receptor β (ERβ), which promotes the expression of key tight junction proteins, sealing the BBB and reducing its permeability. In this study, we investigated the effects of 17β-estradiol (E2) and the selective ERβ agonist diarylpropionitrile (DPN) on endothelial and cancer cells. Western blot analysis revealed the expression patterns of ERs in these cell lines, and estrogen treatment upregulated claudin-5 expression in brain endothelial cells. Using in vitro models of the BBB, we found that DPN treatment significantly increased BBB tightness about suppressed BBB transmigration activity of representative Her2-positive (BT-474) and triple-negative (MDA-MB-231) breast cancer cell lines. However, the efficacy of DPN treatment decreased when cancer cells were pre-differentiated in the presence of E2. Our results support ERβ as a potential target for the prevention and treatment of BCBM and suggest that targeted vector-based approaches may be effective for future preventive and therapeutic implications.

Abstract 673: p38γ MAPK remodels tumor microenvironment facilitating breast cancer progression and brain metastasis

Abstract Major neoplastic diseases have high incidences of brain metastasis (BrM) which is a clinically dreadful consequence of advanced cancers with an abysmal prognosis. Unfortunately, our understanding of the biology and molecular mechanisms underlying BrM remains rudimentary. Improving our understanding of the pathogenesis of BrM will facilitate the rational development and prioritization of new therapeutic strategies. Mitogen-activated protein kinases (MAPKs) are a group of serine/threonine protein kinases that are key players in various intracellular signaling pathways controlling many cellular processes, e.g., growth, differentiation, stress responses, and immune defense which have a key role in cancer progression. However, little is known regarding the role of MAPKs in the pathogenesis of BrM. Here, we report that p38γ mitogen-activated protein kinase (MAPK12) is overexpressed in multiple tumor types and associated with aggressive breast cancer progression and a poor outcome in BrM patients. Interestingly, we found that the lack of p38γ did not impact the proliferation of tumor cells ex vivo, but significantly reduced both the primary tumor growth and BrM in EO771 and other mammary tumor-bearing immunocompetent mouse models. Our preclinical data indicated that p38γ promoted tumor progression and BrM through remodeling tumor microenvironments in vivo. We have mapped the immune landscape of BrM lesions of EO771-bearing mice using high-dimensional single-cell profiling. Clearly, cytometry by time-of-flight (CyTOF) analysis of the BrM immune infiltrates revealed reprogramming of the immunosuppressive brain microenvironment toward a proinflammatory and antitumoral state with tumor-intrinsic p38γ depletion, as indicated by highly enriched dendritic cell (DC) and cytolytic T cell (CTL) populations in BrM. To explore the impact of p38γ depletion in breast cancer cells, we performed RNA sequencing on EO771 cells having p38γ knocked down versus the control cells. We found that p38γ knocked down led to the upregulation of pathways related to immune cell movement, thereby leading to an increased accumulation of antitumor immune cells in BrM. Together, our findings uncover an important role for tumor-intrinsic p38γ in shaping the brain immune microenvironment and underscore the potential of specific p38γ blockade in enhancing antitumor immunity for the treatment of breast cancer BrM. Citation Format: Xiangliang Yuan, Hao-Nien Chen, Akosua Badu-Nkansah, Yimin Duan, Dihua Yu. p38γ MAPK remodels tumor microenvironment facilitating breast cancer progression and brain metastasis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 673.

Treatment Patterns and Outcomes of Women with Symptomatic and Asymptomatic Breast Cancer Brain Metastases: A Single-Center Retrospective Study.

Breast cancer is the most common cancer among women worldwide and the second leading cause of brain metastases (BrM). We assessed the treatment patterns and outcomes of women treated for breast cancer BrM at our institution in the modern era of stereotactic radiosurgery (SRS). We conducted a retrospective analysis of women (≥18 years of age) with metastatic breast cancer who were treated with surgery, whole brain radiotherapy (WBRT), or SRS to the brain at the Sunnybrook Odette Cancer Centre, Toronto, Canada, between 2008 and 2018. Patients with a history of other malignancies and those with an uncertain date of diagnosis of BrM were excluded. Descriptive statistics were generated and survival analyses were performed with subgroup analyses by breast cancer subtype. Among 683 eligible patients, 153 (22.4%) had triple-negative breast cancer, 188 (27.5%) had HER2+, 246 (36.0%) had hormone receptor (HR)+/HER2-, and 61 (13.3%) had breast cancer of an unknown subtype. The majority of patients received first-line WBRT (n = 459, 67.2%) or SRS (n = 126, 18.4%). The median brain-specific progression-free survival and median overall survival (OS) were 4.1 months (interquartile range [IQR] 1.0-9.6 months) and 5.1 months (IQR 2.0-11.7 months) in the overall patent population, respectively. Age >60 years, presence of neurological symptoms at BrM diagnosis, first-line WBRT, and HER2- subtype were independently prognostic for shorter OS. Despite the use of SRS, outcomes among patients with breast cancer BrM remain poor. Strategies for early detection of BrM and central nervous system-active systemic therapies warrant further investigation. Although triple-negative breast cancer and HER2+ breast cancer have a predilection for metastasis to the central nervous system (CNS), patients with hormone receptor-positive/HER2- breast cancer represent a high proportion of patients with breast cancer brain metastases (BrM). Hence, clinical trials should include patients with BrM and evaluate CNS-specific activity of novel systemic therapies when feasible, irrespective of breast cancer subtype. In addition, given that symptomatic BrM are associated with shorter survival, this study suggests that screening programs for the early detection and treatment of breast cancer BrM warrant further investigation in an era of minimally toxic stereotactic radiosurgery.

Abstract A011: Preclinical models of breast cancer brain metastasis for drug efficacy studies

Abstract Background: Overall, 10-30% of patients with metastatic breast cancer (BC) will develop brain metastases. Depending on the subtype of the primary breast cancer the incidence of brain metastases varies ranging from 14% (hormone receptor positive BC) to 46% (triple-negative BC) and approximately about 34% for patients with HER2-positive BC. The major impact of the blood-brain-barrier (BBB), BBB efflux pumps and the local microenvironment in the brain represent a challenge for treatment of BC brain metastasis and treatment options remain limited. The aim of this study was to develop a model system of breast cancer brain metastases for evaluation of drugs directed at BC brain metastases. Methods: Models of BC brain metastasis were established by intracranial stereotactic injection of enzymatically digested PDX tumors (ST340, ST941, ST1339, ST1616B, ST1360B, and ST3338) or by intracardiac or intracarotid injection of cell suspensions in nude mice. Contrast-enhanced T1- and T2-weighted magnetic resonance imaging (MRI) or bioluminescence imaging was used to determine tumor take and growth. Drug sensitivity to single agent trastuzumab emtansine (T-DM1) administered intravenously were performed at confirmed tumor take in a subset of the models. Mice were treated with either saline or T-DM1, 10 mg/kg/week x4 or 2 mg/kg/week x4. PET imaging with 18F-FES was applied in estrogen receptor (ER) positive models as a PD biomarker of anti-estrogen receptor endocrine therapy. Results: T-DM1 treatment in the intracranial ST1339 or ST3338 HER2 positive (3+) PDX models inhibited tumor growth and prolonged survival compared to non-treated animals. However, T-DM1 treatment only caused a modest growth delay in the ST3338 model established intracranially compared to a complete response in the model established subcutaneously. Delivery of T-DM1 across the BBB to the intracranial tumors was visualized by 64Cu-trastuzumab PET/CT and high tumor uptake was associated with a response to T-DM1 therapy in the ST1339 model. Models of BC brain metastasis were successfully established by the intracardiac or intracarotid methods for the triple negative BC cell line MDA-MB-231, the HER2 positive cell line BT474, and an ER positive cell line (ST941C). In vivo imaging with 18F-FES PET/CT was able to visualize intracranial ER positive BC tumors, and animals treated with fulvestrant exhibited reduced 18F-FES tumor uptake. Conclusion: We have established model systems of BC brain metastasis and drug efficacy evaluation. Treatment response to T-DM1 was observed in intracranial HER2 positive models and delivery of T-DM1 to the tumors was visualized by 64Cu-trastuzumab PET/CT imaging. Together, the established breast cancer brain metastases models in combination with advanced non-invasive imaging can be used as a relevant translational platform for evaluation of new drugs. Citation Format: Carsten H. Nielsen, Michael J. Wick, Lotte K. Kristensen, Henriette S. Joergensen, Maria Z. Alfsen, Mark U. Juul, Alyssa Moriarty, Kyriakos P. Papadopoulos, Andreas Kjaer. Preclinical models of breast cancer brain metastasis for drug efficacy studies [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr A011. doi:10.1158/1535-7163.TARG-19-A011

A novel panel of differentially-expressed microRNAs in breast cancer brain metastasis may predict patient survival

Breast cancer brain metastasis (BCBM) is an area of unmet clinical need. MicroRNAs (miRNAs) have been linked to the metastatic process in breast cancer (BC). In this study, we aim to determine differentially-expressed miRNAs utilising primary BCs that did not relapse (BCNR, n = 12), primaries that relapsed (BCR) and their paired (n = 40 pairs) brain metastases (BM) using the NanoString™ nCounter™ miRNA Expression Assays. Significance analysis of microarrays identified 58 and 11 differentially-expressed miRNAs between BCNR vs BCR and BCR vs BM respectively and pathway analysis revealed enrichment for genes involved in invasion and metastasis. Four miRNAs, miR-132-3p, miR-199a-5p, miR-150-5p and miR-155-5p, were differentially-expressed within both cohorts (BCNR-BCR, BCR-BM) and receiver-operating characteristic curve analysis (p = 0.00137) and Kaplan-Meier survival method (p = 0.0029, brain metastasis-free survival; p = 0.0007, overall survival) demonstrated their potential use as prognostic markers. Ingenuity pathway enrichment linked them to the MET oncogene, and the cMET protein was overexpressed in the BCR (p < 0.0001) and BM (p = 0.0008) cases, compared to the BCNRs. The 4-miRNAs panel identified in this study could be potentially used to distinguish BC patients with an increased risk of developing BCBM and provide potential novel therapeutic targets, whereas cMET-targeting warrants further investigation in the treatment of BCBM.

Abstract 49: Stromal platelet derived growth factor receptor (PDGFRβ) signaling: A novel therapeutic target for breast cancer brain metastasis (BCBM)

Abstract Stromal PDGFRβ has emerged as an actionable mediator of breast tumor-stromal communication. As a receptor tyrosine kinase, PDGFRβ is activated by its ligand, PDGFB, which is released by neighboring tumor epithelium and endothelium. However, how PDGF signaling mediates breast cancer initiation, progression, and metastasis remains unclear. To evaluate PDGFRβ in this disease, we developed a mouse model of stromal-specific PDGFRβ activation using the Fsp-cre transgene previously published by our group (PDGFRβ mutant). PDGFRβ mutant mammary glands exhibit increased tertiary side-branching and epithelial proliferation confirming a stromal-specific PDGFRβ effect on neighboring epithelium. To evaluate the functional relevance of PDGFRβ activation on metastatic progression, we performed tail vein injection of PDGFB expressing murine mammary tumor cells and, surprisingly, observed brain metastases in 50% of the PDGFRβ mutant mice while no brain lesions were seen in controls. There was no difference in the incidence of lung, liver or bone metastases. Mammary tumor cells expressing low PDGFB did not exhibit a similar increase in brain metastases in mutant mice. While there is no observable difference in blood brain barrier permeability in the mutant mice, we bypassed this variable by intracranially injecting mammary tumor cells and found that larger tumors formed in the brains of PDGFRβ mutant mice versus controls. To our knowledge, this is the first example where genetic manipulation of the stroma leads to an increased incidence of BCBM. Also, our pre-clinical data suggests that primary breast tumors that express high PDGFB could preferentially metastasize to the brain. To test this in patients, we analyzed PDGFB protein expression in a tissue microarray comprised of HER2-positive and triple negative breast cancer (TNBC) primary tumors. While high PDGFB did not correlate with site-independent metastatic recurrence, it was prognostic of brain metastasis, mirroring our mouse data. Evaluation of PDGFB in a small cohort of matched primary breast tumors with associated brain (n=5) and lung metastases (n=2) revealed intense PDGFB staining in 100% of the brain metastases, but only 50% of the lung metastases. Our findings suggest high primary tumor PDGFB expression defines a subset of breast cancer patients predisposed to brain metastases. These patients may benefit from therapeutic intervention of PDGFRβ signaling. To test this pre-clinically, we treated mice harboring intracranial tumors with the PDGFR specific inhibitor, Crenolanib. Excitingly, Crenolanib treatment significantly inhibited the brain tumor burden in these mice. Combined, our findings (1) advocate that primary tumor expression of PDGFB is a novel prognostic biomarker for the development of BCBM and (2) support clinical trial evaluation of PDGFR inhibitors for the prevention and treatment of BCBM. Citation Format: Katie A. Thies, Anisha M. Hammer, B. Eason Hildreth, Luke O. Russell, Steven T. Sizemore, Anthony J. Trimboli, Raleigh D. Kladney, Chelsea M. Bolyard, Robert Pilarski, Lynn Schoenfield, Jose Otero, Arnab Chakravarti, Matthew Ringel, Balveen Kaur, Gustavo Leone, Michael C. Ostrowski, Gina M. Sizemore. Stromal platelet derived growth factor receptor (PDGFRβ) signaling: A novel therapeutic target for breast cancer brain metastasis (BCBM) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 49.

Abstract 50: Elucidating the role of MUC5AC-MET axis in breast cancer brain metastasis

Abstract Metastasis of breast cancer (BC) is the leading cause of mortality in American women. In particular, brain metastasis is a significant clinical problem present in 30-40% of triple receptor negative (TN) and epidermal growth factor receptor 2 (HER2) positive BC patients. These patients also have the worst prognosis of all breast cancers in women. Due to advances in clinical management at both the diagnostic and therapeutic levels, the lifespan or overall survival of these patients has increased, but the manifestation of brain metastasis at later stages of the disease remains an unfortunate burden for these patients. In addition, the blood-brain barrier (BBB) poses an additional hurdle for treatment of BC brain metastases, because the majority of chemotherapeutic drugs fail to cross the BBB. Furthermore, there is no single targeted therapy available for TNBC patients with brain metastasis, and thus there is an urgent requirement to discover novel biomarkers and therapeutics to address BC brain metastasis. In this regard, using a bioinformatics approach, we observed that several mucins, including MUC5AC, are significantly up-regulated in brain metastases of BC compared to primary tumors. However, we found the secretory mucin MUC5AC protein to be substantially high in brain-seeking BC (BSBC) cell lines and metastatic brain tissues. We also observed that knockdown of MUC5AC reduced proliferation and metastatic potential in these cell lines. Furthermore, we observed that MUC5AC colocalizes with activated MET receptor. MUC5AC knockdown in BSBC cell lines reduced MET activation and its downstream targets FAK and paxillin. Interestingly, MET and FAK inhibition using pharmacological inhibitors led to substantial decrease in MUC5AC expression. Overall, these studies suggest that MUC5AC-MET axis may regulate breast cancer brain metastasis. Understanding the MUC5AC-MET axis could be a novel approach for the development of better prognosis and prevention of life-threatening and treatment-resistant breast cancer brain metastasis. Citation Format: Mohd W. Nasser, Shailendra K. Gautam, Ranjana Kanchan, Pranita Atri, Jawed Siddiqui, Rakesh Bhatia, Joseph Carmicheal, Dario Ghersi, Sukhwinder Kaur, Siddharth Mahapatra, Maneesh Jain, Surinder K. Batra. Elucidating the role of MUC5AC-MET axis in breast cancer brain metastasis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 50.

Abstract P2-05-03: Whole genome transcriptome analysis of sequential breast to brain metastasis uncovers new signalling pathways and druggable targets

Abstract The occurrence of brain metastasis (BM) in breast cancer (BC) is currently on the rise across all molecular subtypes with 10-30% reported incidence. The need to uncover the mechanisms underlying this clinically devastating complication is apparent, and in the current study we sought to identify BC cell mediators of BM. In our cohort of metastatic patients (n=196) we found that BM developed in 13% of the cases. Despite the previous reports of negative ER status being a risk factor for BM, the ER+ve patients accounted for 42% of all diagnosed BM. To elucidate the gene alterations required for successful colonisation of the brain we undertook RNA sequencing (RNA-seq) of sequential breast to brain metastasis of known receptor status (n=7).This study presents the first whole transcriptome next-generation RNA-seq analysis of resected BM and their matching primary breast tumours. We identified 500 differentially expressed genes (DEGs) (&amp;lt; 0.05, fcThreshold &amp;gt;±1.5), accounting for those that were both upregulated and downregulated in BM compared to the primary. Analysis of protein-coding genes identified collective ER-specific metastatic pathways. Additionally, common functional pathways altered included ECM, cell adhesion and neuronal differentiation. Our analysis of the BM transcriptomic landscape and verification in cell line models that preferentially metastasise to the brain has unravelled a complex network of driver genes, cooperating with stromal derived factors, responsible for the organ-specific behaviour of the metastatic cells. Genes such as ANTRX1, THBS2, FAP, VCAN and TIMP2 were found to be part of the invasion and migration network that drives the extravasation of the BM cells. Furthermore, an EMT stemness signalling network driven by ANTRX1and WNT pathway driven RUNX was prominent in the cells acquiring the ability to migrate to the brain. Additional work is being carried out on uncovering the adaptations that re-activate the dormant brain metastatic cells and the contribution of the neuronal niche in the facilitating the colonisation by the MBC. This study highlights the requirement of unique gene sets for the invasion, migration and colonisation to the brain and that functional characterisation of the DEGs will enable the identification of novel molecular targets for prevention and treatment of breast cancer BM. Citation Format: Varešlija D, Fagan A, Buckley P, Farrell M, Hill A, Young L. Whole genome transcriptome analysis of sequential breast to brain metastasis uncovers new signalling pathways and druggable targets. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P2-05-03.

Abstract P1-07-26: Global analysis of the transcriptome in matched primary and metastatic tumours defines ER specific gene alterations

Abstract The incidence of brain metastasis (BM) among women with metastatic breast cancer (MBC) is currently on the rise, and it is estimated that between 10-30% of patients diagnosed with breast cancer may also develop BM (Weil 2005). BM is considered a late complication in the clinical setting and is an infrequent occurrence even in mice studies that readily metastasise to other organs (Valiente 2014). While pre-menopausal status and negative estrogen receptor (ER) status are seen as main risk factors (Gil-Gil 2013), it is now recognised that BM is emerging as an increasing clinical problem across the various MBC subtypes. BM patients have very poor overall survival and as a result it is crucial to identify the factors that promote the survival and adaptation of breast cancer cells to allow them to colonise distant sites such as the brain. The ability to predict the BM potential could be of great clinical importance and in this study we decided to investigate the mechanisms underlying BM across the various MBC subtypes. To our surprise, in a cohort of breast cancer patients we found a comparable number of ER positive and ER negative BM. We established that ER positive patients (n=10) had a substantially longer disease latency period (median disease free survival (DFS) 36 months, range 8-85 months) in comparison to ER negative patients (n=8, HER2 positive, n=2, triple negative, n=6), (median DFS 24 months, range 9-60 months). To understand and elucidate the gene alterations required for successful colonisation of the brain we undertook RNAseq of sequential primary and brain metastatic tumours from ER positive (n=4) and ER negative (n=3) breast cancer patients. Significant elevations in gene expression were observed in the brain metastatic tumours in comparison to the matched primary. Though a large degree of patient heterogeneity was observed, common ER-specific metastatic pathways were identified. This study highlights the requirement of unique gene sets for the colonisation to the brain and that functional characterisation of the differentially expressed genes will enable the identification of novel molecular targets for prevention and treatment of breast cancer BM. Citation Format: Damir Vareslija, Ailis Fagan, Jean McBryan, Patrick Buckley, Michael Farrell, Arnold DK Hill, Leonie Young. Global analysis of the transcriptome in matched primary and metastatic tumours defines ER specific gene alterations [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P1-07-26.

Abstract P6-11-11: Characteristics of long-term survivors after brain metastases in breast cancer patients

Abstract Background: Brain metastases (BM) occur in 10%-15% patients of breast cancer patients. It is associated with poor prognosis, requiring great effort to manage local and systemic treatment for BM. The purpose of this study was to analyze the clinico-pathological characteristics of long-term survivors with BM in breast cancer patients. Method: 63 patients with breast cancer BM diagnosed from 2002 to 2010 at the Tokyo Metropolitan Komagome hospital were included. Long–term survival group (Long) was defined as to be consisted of the patients with survival duration more than 36 months after diagnosed with BM and the patients with less than 36 month was into Short-term survival group (Short) in this study. The clinico-pathological characteristics were compared between these two groups. Survival rate and prognostic factors of BM were analyzed by the Kaplan–Meier method and employed by Log–Rank test. Multivariate analysis was performed by the Cox proportional hazard model. Results: Median age of the 63 patients was 53 years (range, 35–78). Median survival time after BM was 12 months (range, 1–168), with about 90 percent of cause of death related to BM (e.g. failure of PS due to BM). As for ER and HER2 status, the number of ER+/HER2- (Luminal:Lum), ER+or-/HER2+ (HER2-enrich:Her2-E), ER-/HER2- (Basal:Bas) were 18, 27, 18, respectively. Among those 63 patients, 11 survived 36 months or more after BM. However, there was no difference in the rate of ER status between Long (55%) and Short (38%), there were significantly high rate of Her2-E case in Long (73%) as compared with Short (29%). Median survival duration after diagnosed with BM of Lum, Her2-E and Bas were 11, 37, 3 months, respectively. Prognosis of Bas was significantly poor (Bas vs. Her2-E p&amp;lt;0.001), and although Her2-E was not significant as compared with ER (p = 0.188), survival time after BM of Her2-E was the tendency to be long. In univariate analysis, Karnofsky performance status (KPS≥70 or &amp;lt;70), HER2 status, disease free interval (from initial diagnosis to first recurrence, DFI≥2years or &amp;lt;2years) had significant impact on survival time after BM. (p = 0.0458, 0.0398, 0.0385, respectively). Meningitis status was a borderline. (p = 0.052) In multivariate analysis, KPS, HER2 status and DFI were significant prognostic factors. (KPS: RR 2.08, 95% CI 1.08-4.07; HER2: RR 2.911, 95% CI 1.396- 6.484; DFI: RR 1.933, 95% CI 0.83-4.102) Conclusions: Although, it was believed that the prognosis after BM was poor, Her2-E BM had a comparatively good prognosis. An existing report supports extension of the survival time after BM by HER2–targeted treatment in BM cases with Her2 positive breast cancer. This newest study reviles the median survival after BM as 37 months in Her2-E BM group, but that of Bas group was only 3 months and this is not improved at all compared with historically reported survival duration (2.4-4.9months). Our reports suggested that the innovation of Her2–targeted treatment leads this surprising improvement of life extension in HER2 positive BM patients but innovation of cytotoxic agents could not contribute toward improvement of clinical outcome in triple negative BM patients. So the necessity of examining the medical treatment of breast cancer BM according to subtype from now on is also considered. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-11-11.

Abstract C291: Targeting SDF-1 (CXCL12) pathway to inhibit the recurrence of breast cancer brain metastases after whole-brain irradiation.

Abstract The presence of tumor-associated macrophages (TAMs) in tumors strongly correlates with poor outcome. At least one lineage of TAMs originates from the peripheral bone marrow-derived mononuclear cells. We have previously reported that bone marrow-derived CD11b+ myeloid cells contribute to tumor regrowth after irradiation by homing to the irradiated site, where they aid in restoring tumor vasculature. We have also shown that inhibiting the recruitment of CD11b+ monocytes/macrophages by blocking the SDF-1 (CXCL12)-CXCR4 axis prevents or delays recurrence of mouse and rat glioblastoma after irradiation. We further demonstrate that TAMs in the irradiated glioblastoma could be detected in vivo by magnetic resonance (MR) imaging of iron oxide nanoparticles phagocytosed by TAMs. Radiation remains one of the major modalities for treatment of breast cancer brain metastases (BCBMs). We hypothesized that inhibition of SDF-1 mediated neovasculogenesis may be as useful for treatment of BCBMs as it is for treatment of glioblastoma. In this study, brain metastases from MDA-MB-231-BR3 cells injected through intra-carotid artery in nude mice were detected by bioluminescence imaging. SDF-1 activity was inhibited using Spiegelmer NOX-A12. Treatment with NOX-A12 began immediately after irradiation, and continued every second day until the end of the experiment. We show that combination of NOX-A12 with 12Gy resulted in marked delay of metastatic regrowth after irradiation compared to 12Gy alone and a doubling of the survival time of the mice. Detection of TAMs using MR imaging of iron oxide nanoparticles is under way. Citation Information: Mol Cancer Ther 2013;12(11 Suppl):C291. Citation Format: Sophia Chernikova, G-One Ahn, Shie-Chau Liu, Jason Stafford, J. Martin Brown. Targeting SDF-1 (CXCL12) pathway to inhibit the recurrence of breast cancer brain metastases after whole-brain irradiation. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr C291.

Primary systemic treatment of breast-cancer brain metastases

Primary systemic treatment of breast-cancer brain metastases