Project description:Patients with metastatic breast cancer (MBC) typically have short survival times and their successful treatment represents one of the most challenging aspects of patient care. This poor prognostic behavior is in part due to molecular features including increased tumor cell clonal heterogeneity, multiple drug resistance mechanisms, and alterations of the tumor microenvironment. The AURORA US Metastasis Project was established with the goal to identify molecular features specifically associated with metastasis. We therefore collected and molecularly characterized specimens from 55 metastatic breast cancer (BC) patients representing 51 primary cancers and 102 metastases. The 153 unique tumors were assayed using RNAseq, tumor/germline DNA exomes and low pass whole genome sequencing, and global DNA methylation microarrays. We found intrinsic molecular subtype differences between primary tumors and their matched metastases to be rare in triple negative breast cancer (TNBC)/Basal-like subtype tumors. Conversely, tumor subtype changes were relatively frequent in estrogen receptor positive (ER+) cancers where ~30% of Luminal A cases switched to Luminal B or HER2-enriched (HER2E) subtypes. Clonal evolution studies identified changes in expression subtype coincident with DNA clonality shifts, especially involving HER2 amplification and/or the HER2E expression subtype. In contrast, we found remarkable conservation of cancer-associated DNA hypermethylation profiles within primary tumor-metastasis pairs. We further found evidence for ER-mediated downregulation of genes involved in cell-cell adhesion in metastases. Microenvironment differences varied according to tumor subtype where ER+/Luminal metastases had lower fibroblast and endothelial cell content, while TNBC/Basal-like metastases showed a dramatic decrease in B cells and T cells. In 17% of metastatic tumors, we identified DNA hypermethylation and/or focal DNA deletions near HLA-A that were associated with its significantly reduced expression, and with lower immune cell infiltrates. We also identified low immune cell features in brain and liver metastases when compared to other metastatic sites, even within the same patient. These findings have implications for the treatment of metastatic breast cancer patients with immune- and HER2-targeting therapies and suggest potential novel therapeutic avenues for the improvement of outcomes for some patients with MBC

Project description:The goal of this dataset is to compare the gene expression patterns between primary and metastatic tumors Metastatic cancer patients typically have short survival times and their successful treatment represents one of most challenging aspects of patient care. This poor prognostic behavior is likely due to many factors, including increased clonal heterogeneity, multiple drug resistance mechanisms, and the role of the tumor microenvironment. The AURORA US Metastasis Project was established to collect and molecularly characterize specimens from 55 breast cancer (BC) patients representing 51 primary cancers and 102 metastases. The 153 unique tumors were assayed using RNAseq, tumor/germline DNA exomes and low pass whole genome sequencing, and global DNA methylation microarrays. We found intrinsic molecular subtype differences between primary tumors and their matched metastases to be rare in triple negative breast cancer (TNBC)/Basal-like subtype tumors. Conversely, tumor subtype changes were relatively frequent in estrogen receptor positive (ER+) cancers where ~30% of Luminal A cases switched to Luminal B or HER2-enriched (HER2E) subtype. Clonal evolution studies identified changes in expression subtype coincident with DNA clonality shifts, especially involving HER2 amplification and/or the HER2E expression subtype. Microenvironment differences varied according to tumor subtype where ER+/Luminal metastases had lower fibroblast and endothelial cell content, while TNBC/Basal-like metastases showed a dramatic decrease in adaptive immunity. In 17% of metastatic tumors, we identified DNA methylation and/or focal DNA deletions near HLA-A that were associated with its significantly reduced expression, and with lower immune cell infiltrates. We also identified low immune cell features in brain and liver metastases when compared to other metastatic sites, even within the same patient. These findings have direct implications for the treatment of metastatic breast cancer patients with immune- and HER2-targeting therapies and suggest potential novel therapeutic avenues for the improvement of outcomes for some MBC patients.

Project description:Metabolic rewiring is essential for breast tumor growth and progression to metastatic disease, yet little is known regarding how cancer cells modify their acquired metabolic programs in response to different metastatic microenvironments. Transcriptional and metabolomic analysis have previously shown that liver-metastatic breast cancer cells adopt an intrinsic metabolic profile characterized by increased HIF-1α activity and dependence on glycolysis. Stable isotope tracing analysis (SITA) performed in vivo confirmed that the glycolytic nature of liver-metastatic breast cancer cells is retained when these cells are grown as primary tumors or as liver metastases. However, our data also reveal that unique metabolic adaptations are specifically induced by the liver microenvironment. Indeed, liver metastases display elevated expression of genes involved in glutathione (GSH) biosynthesis and reactive oxygen species (ROS) detoxification when compared to primary tumors. Moreover, breast cancer liver metastases rely strongly on glucose and glutamine-derived carbons to support de novo GSH synthesis. Glutathione is a tripeptide that acts as a major scavenger for reactive oxygen species (ROS). Liver metastases display reduced levels of 8-Oxo-2'-deoxyguanosine, confirming their increased capacity to buffer ROS. We demonstrated the dependence of liver metastases formation on these distinct metabolic adaptations by depleting glutamate-cysteine ligase (Gcl), the rate-limiting enzyme in glutathione biosynthesis. Gcl depletion, and decreased GSH levels, strongly reduced the capacity of liver-metastatic cells to form distant metastasis within the liver. We performed gene expression analysis of liver metastasis and primary tumors from liver-metastatic breast cancer cells derived from 4T1 cells. 4T1-2776 (76) and 4T1-2792 (92) cells were injected in the mammary fat pads of BALB/c and grown as primary tumors or were grown as liver metastasis after splenic injection. Tissues were harvested from primary tumors and liver metastasis and submitted to laser-capture microdissection (LCM). For liver metastasis, tumour tissue was harvested at 10 days, 2 weeks and 3 weeks after splenic injection. For each time point, tissue was isolated from the tumor centre (core), a peripheral area of the tumor (margin), a region of the liver proximal to the tumor (adjacent) and a region of the liver far from the tumor (distant). For primary tumors from 4T1-2776 cells (1034, 1036, 1043) and 4T1-2792 (MFP2L, MFP3L, MFP5L) tissue was collected from the tumor core and margin, at the experimental endpoint.

Project description:Background & Aims: The metastatic process is complex and remains a major obstacle in the management of colorectal cancer (CRC). To gain a better insight into the biologic events driving the metastatic process we investigated genomic aberrations in a large cohort of matched CRC primaries and distant metastases from various sites. Methods: In total, 62 primary colorectal cancers, 62 matched normal specimens, and 68 matched metastases (from liver, lung, ovary, omentum, and distant lymph nodes) were analyzed by high resolution array comparative genomic hybridization (array CGH) for DNA copy number changes. Findings were validated using a publicly available dataset consisting of 21 primary tumors and matched liver metastases. Fluorescence in situ hybridization (FISH) was used to confirm some of the DNA copy number changes observed. Results: Overall patterns of DNA copy number aberrations were highly similar between primary tumors and their metastases, confirming clonality. Additional copy number aberrations in metastasis are rare and rather than recurrent they were sporadic for individual patients. The only recurrent differences between primary tumors and their metastases were two chromosomal regions, 6q21 and 8q24.21 encompassing the MYC oncogene, that coamplified in three metastases of two patients (3.2%). FISH analysis confirmed the high level co-amplification in the metastasis, which were not detected in their primary tumors. Conclusions: Primary CRC and their metastases show highly similar patterns of DNA copy number changes, additional copy number aberrations in metastasis are rare and recurrences exceptional. These observations are consistent with the hypothesis that the metastatic potential is predestined early in the development of the primary tumor. In total, 62 primary colorectal cancers, 62 matched normal specimens, and 68 matched metastases (liver, lung, ovarian, omentum and distant lymph nodes) were analyzed by high resolution array comparative genomic hybridization (array CGH).

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Targeting Metabolic Adaptations in the Breast Cancer–Liver Metastatic Niche Using Dietary Approaches to Improve Endocrine Therapy Efficacy

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