Project description:Brain metastases from breast and other cancers constitute an important part of therapeutic failures and are associated with severe morbidity and mortality. Here, we have examined histopathological data and generated gene expression data in two independent cohorts of primary tumors from HER2-positive advanced breast cancer patients. We report that the combination of estrogen receptor (ER) negativity and expression of a novel 13-gene signature identify a subset of patients with rapid (median, 31 and 41 months in discovery and validation cohorts, respectively) versus slower (median, 66 months and 77 months in discovery and validation cohorts, respectively) development of brain metastases (P<0.0001). The 13-gene signature also predicted rapid brain metastasis formation within the ER-negative subset of patients (P=0.014). Interestingly, three of the genes in the signature (RAD51, BARD1, FANCG) function in DNA double strand break repair. Overexpression of RAD51 in immortal MCF-10A breast epithelial cells altered their three-dimensional acinar morphology to increase the percentage of invasive structures by 6.5 fold, in the presence or absence of HER2 overexpression. In summary, ER negativity and a novel 13-gene signature may have the potential to identify subpopulations at highest immediate risk for the development of brain metastases in HER2-positive advanced breast cancer. Our results also suggest that RAD51, found in the 13-gene signature, may promote aggressiveness in breast epithelial cells. These data may be useful in the design of brain metastasis preventive trials and may prompt new treatment strategies Median normalized data provided
Project description:Purpose: There is an unmet clinical need for biomarkers to identify breast cancer patients who are at increased risk of developing brain metastases. The objective is to identify gene signatures and biological pathways associated with HER2+ brain metastasis. Experimental Design: Gene expression of 19 HER2+ breast cancer brain metastases was compared with HER2+ nonmetastatic primary tumors. Gene Set Enrichment Analysis was used to identify a signature, which was evaluated for correlation with BRCA1 mutation status and clinical outcome using published microarray datasets and for correlation with pharmacological inhibition by a PARP inhibitor and temozolomide using published microarray datasets of breast cancer cell lines. Results: A BRCA1 Deficient-Like (BD-L) gene signature is significantly correlated with HER2+ metastases in both our and an independent cohort. BD-L signature is enriched in BRCA1 mutation carrier primary tumors and HER2-/ER- sporadic tumors, but high values are found in a subset of ER+ and HER2+ tumors. Elevated BD-L signature in primary tumors is associated with increased risk of overall relapse, brain relapse, and decreased survival. The BD-L signature correlates with pharmacologic response to PARP inhibitor and temozolomide in two independent microarray datasets, and the signature outperformed four published gene signatures of BRCA1/2 deficiency. Conclusions: The BD-L signature is enriched in breast cancer brain metastases and identifies a subset of primary tumors with increased propensity for brain metastasis. Furthermore, this signature may serve as a biomarker to identify sporadic breast cancer patients who could benefit from a therapeutic combination of PARP inhibitor and temozolomide. Gene expression of 19 HER2+ human breast cancer brain metastases was compared with gene expression of 19 HER2+ nonmetastatic primary human breast tumors.
Project description:Breast cancer in young patients is known to exhibit more aggressive biological behavior and is associated with a less favorable prognosis than the same disease in older patients, owing in part to an increased incidence of brain metastases, the mechanistic explanations behind which remain poorly understood. We recently reported that young mice, compared to older mice, showed about a three-fold increase in the development of brain metastases in mouse models of triple-negative and luminal B breast cancer. Here we have performed a quantitative mass spectrometry-based proteomic analysis to identify proteins contributing to age-related disparities in the development of breast cancer brain metastases. Using a mouse model of brain-tropic (MDA-MB-231BR) triple-negative breast cancer, we harvested subpopulations of tumor metastases, the tumor-adjacent metastatic microenvironment, and uninvolved brain tissues via laser microdissection followed by quantitative proteomic analysis using high resolution mass spectrometry to characterize differentially abundant proteins contributing to age-dependent rates of brain metastasis.
Project description:Purpose: There is an unmet clinical need for biomarkers to identify breast cancer patients who are at increased risk of developing brain metastases. The objective is to identify gene signatures and biological pathways associated with HER2+ brain metastasis. Experimental Design: Gene expression of 19 HER2+ breast cancer brain metastases was compared with HER2+ nonmetastatic primary tumors. Gene Set Enrichment Analysis was used to identify a signature, which was evaluated for correlation with BRCA1 mutation status and clinical outcome using published microarray datasets and for correlation with pharmacological inhibition by a PARP inhibitor and temozolomide using published microarray datasets of breast cancer cell lines. Results: A BRCA1 Deficient-Like (BD-L) gene signature is significantly correlated with HER2+ metastases in both our and an independent cohort. BD-L signature is enriched in BRCA1 mutation carrier primary tumors and HER2-/ER- sporadic tumors, but high values are found in a subset of ER+ and HER2+ tumors. Elevated BD-L signature in primary tumors is associated with increased risk of overall relapse, brain relapse, and decreased survival. The BD-L signature correlates with pharmacologic response to PARP inhibitor and temozolomide in two independent microarray datasets, and the signature outperformed four published gene signatures of BRCA1/2 deficiency. Conclusions: The BD-L signature is enriched in breast cancer brain metastases and identifies a subset of primary tumors with increased propensity for brain metastasis. Furthermore, this signature may serve as a biomarker to identify sporadic breast cancer patients who could benefit from a therapeutic combination of PARP inhibitor and temozolomide.
Project description:The development of efficacious therapies targeting metastatic spread of breast cancer to the brain represents an unmet clinical need. Accordingly, an improved understanding of the molecular underpinnings of central nervous system spread and progression of breast cancer brain metastases (BCBM) is required. In this study, the clinical burden of disease in BCBM was investigated, as well as the role of aldehyde dehydrogenase 1A3 (ALDH1A3) in the metastatic cascade leading to BCBM development. Initial analysis of clinical survival trends for breast cancer and BCBM determined improvement of breast cancer survival rates, however this has failed to positively impact the prognostic milestones of triple-negative breast cancer (TNBC) brain metastases (BM). ALDH1A3 and a representative epithelial-mesenchymal transition (EMT) gene signature (mesenchymal markers CD44, Vimentin) were compared in tumors derived from BM, lung metastases (LM) or bone metastases (BoM) of patients as well as mice post-injection of TNBC cells. Selective elevation of the EMT signature and ALDH1A3 were observed in BM, unlike LM and BoM, especially in the tumor edge. Furthermore, ALDH1A3 was determined to play a role in BCBM establishment via regulation of circulating tumor cell (CTC) adhesion and migration phases in the BCBM cascade. Validation through genetic and pharmacologic inhibition of ALDH1A3 via lentiviral shRNA knockdown and a novel small molecule inhibitor demonstrated selective inhibition of BCBM formation with prolonged survival of tumor-bearing mice. Given the survival benefits via targeting ALDH1A3, it may prove an effective therapeutic strategy for BCBM prevention and/or treatment.
Project description:To gain insights into tumor heterogeneity in anti-cancer drug responses of patient-derived xenograft models of HER2+ breast cancer brain metastases, we performed transcriptome gene expression profiling by Ion AmpliSeq™ Transcriptome sequencing that targets more than 20,000 human genes. Our data found that all anti-cancer drugs responders have significantly higher expression levels of AKT-mTOR-dependent signature genes as compared to the non-responders, suggesting that most HER2+ breast cancer brain metastases are depend on the AKT-mTOR pathway
Project description:Genome-wide DNA methylation profiling of brain metastases from lung cancer, breast cancer, and melanoma samples. The Illumina Infinium 450K Human DNA methylation Beadchip was used to obtain DNA methylation profiles across approximately 450,000 methylation sites in formalin-fixed paraffin-embedded (FFPE) samples from brain metastases. Samples included 30 breast cancer brain metastases, 18 lung cancer brain metastases, 37 melanoma brain metastases, and 4 samples with brain metastases from patients with uncertain primary.