Identification of ALDH1A3 as a viable therapeutic target in breast cancer metastasis-initiating cells
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ABSTRACT: 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:The survival of women with brain metastases (BM) from breast cancer remains very poor, and more than 80% will die within a year of their diagnosis. Here we define the function of IL13Rα2 in outgrowth of breast cancer brain metastases (BCBM) in vitro and in vivo, and postulate IL13Rα2 as a suitable therapeutic target for BM. Experimental design: We performed IHC staining of IL13Rα2 in BCBM to define its prognostic value. Using inducible-shRNAs in TNBC and HER2+ breast-brain metastatic models we assessed IL13Rα2 function in vitro and in vivo. We performed RNAseq and functional studies to define the molecular mechanisms underlying IL13Rα2 function in BCBM. Results: High IL13Rα2 expression in BCBM predicted worse survival after BM diagnoses. IL13Rα2 was essential for cancer-cell survival, promoting proliferation while repressing invasion. IL13Rα2 KD resulted in repression of cell cycle and proliferation mediator Cyclin D2 and upregulation of Ephrin B1 signaling. Ephrin-B1 (i) promoted invasion of BC cells in vitro, (ii) marked micrometastasis and invasive fronts in BCBM, (iii) predicted shorter disease-free survival (DFS) and BM-free survival (BMFS) in breast primary tumors known to metastasize to the brain. In experimental metastases models, which bypass early tumor invasion, downregulation of IL13Rα2 prior or after tumor seeding and brain intravasation decreased BMs, suggesting that IL13Rα2 and a switch to a more proliferative phenotype is critical to BM outgrowth.
Project description:Metastases in the brain are the most severe and devastating complication of cancer. The incidence of brain metastasis is increasing. Therefore, the need of finding specific druggable targets for brain metastasis is demanding. The aim of this study was to compare the brain (immune) response to brain metastases of the most common tumor lineages, viz., lung adenocarcinoma and breast cancer. Targeted gene expression profiles of 11 brain metastasis of lung adenocarcinoma (BM-LUAD) were compared to 11 brain metastasis of breast cancer (BCBM) using NanoString nCounter PanCancer IO 360™ Panel. The most promising results were validated spatially using the novel GeoMx™ Digital Spatial Profiler (DSP) Technology. Additionally, Immune cell profiles and expression of drug targets were validated by multiplex immunohistochemistry. We found more active immune response in BM-LUAD as compared to BCBM. In the BM-LUAD, 138 genes were upregulated as compared to BCBM (adj. p ≤ 0.05). Conversely, in BCBM 28 genes were upregulated (adj. p ≤ 0.05). Additionally, genes related to CD45+ cells, T cells and cytotoxic T cells showed to be expressed higher in BM-LUAD compared to BCBM (adj. p = 0.01, adj. p = 0.023, adj. p = 0.023, respectively). The spatial quantification of the immune cells using the GeoMx DSP technique revealed the significantly higher quantification of CD14 and CD163 in tumor regions of BM-LUAD as compared to BCBM. Importantly, the immune checkpoint VISTA and IDO1 were identified as highly expressed in the BM-LUAD. Multiplex immunohistochemistry confirmed the finding and showed that VISTA is expressed mainly in BM-LUAD tumor cells, CD3+ cells, and to less levels in some microglial cells in BM-LUAD. This is the first report on differences in the brain immune response between metastatic tumor of different lineages. We found a far more extensive infiltration of immune cells in BM-LUAD as compared to BCBM. In addition, we found higher expression of VISTA and IDO1 in BM-LUAD. Taken together, targeted immune therapy should be considered to treat patients with BM-LUAD.
Project description:Experiment: Expression profiling in breast cancer brain metastases (BC) compared to breast cancers (BC) and primary brain tumors (prBT). The objectives are to identify expression profiles that are specific to BCBM in order to identify new molecular biomarkers. The characterization of the BCBM samples included adjacent genetic techniques.
Project description:Initial screening for potential metastases suppressors down regulated by methylation was performed using breast cancer cell line models specific for site-specific metastasation. Gene expression profiling and qRT-PCR validations were conducted on tumor tissues from primary breast cancer (BC) and BCBM. CADM1 and RECK were further characterized for their methylation patterns and finally the protein expression of CADM1 was validated in a large number of BC and BCBM samples and correlated with clinico-pathologic parameters.
Project description:We used single-cell RNA-sequencing to investigate the role of myeloid cells in a humanized mouse model of breast cancer brain metastasis (BCBM). We generated brain metastases with a cardiac-injection of the human triple-negative breast cancer cell line MDA-MB-231BR2 (231BR) into MITRG mice and allowed tumors to grow in the brain for 25 days. We then took all human cells (includes myeloid cells and 231BR) from these mice verses control MITRG brains (only myeloid cells) to find transcriptional changes associated with BCBM.
Project description:We used single-cell RNA-sequencing to investigate the role of brain-resident microglia versus infiltrating cells in a mouse model of breast cancer brain metastasis (BCBM). We generated brain metastases with a cardiac-injection of the human triple-negative breast cancer cell line MDA-MB-231BR2 (231BR) into Foxn1 nu/nu mice and allowed tumors to grow in the brain for four weeks. We then compared astrocytes (ASCA2+CD45-) and myeloid cells (CD11b+CD45+) from these mice verses control Foxn1 nu/nu brains to find transcriptional changes associated with BCBM.
Project description:Breast cancer is the most common malignancy that develops in women, responsible for the highest cancer-associated death rates. Triple negative breast cancers (TNBC) represent an important subtype that have an aggressive clinical phenotype, are associated with a higher likelihood of metastasis and are not responsive to current targeted therapies. miRNAs have emerged as an attractive candidate for molecular biomarkers and treatment targets in breast cancer, but their role in the progression of TNBC remains largely unexplored. This study has investigated miRNA expression profiles in 31 primary TNBC cases and in 13 lymph node metastases compared with 23 matched normal breast tissues to determine miRNAs associated with the initiation of this disease subtype and those associated with its metastasis. 71 miRNAs were differentially expressed in TNBC, the majority of which have previously been associated with breast cancer, including members of the miR-200 family and the miR-17-92 oncogenic cluster, suggesting that miRNAs involved in the initiation of TNBC are not subtype specific. However, the repertoire of miRNAs expressed in lymph node negative and lymph node positive TNBCs were largely distinct from one another. In particular, miRNA profiles associated with lymph node negative disease tended to be up-regulated, while those associated with lymph node positive disease were down-regulated and largely overlapped with the profiles of their matched lymph node metastases. miRNA expression profiles were examined in 31 primary TNBC cases and in 13 lymph node metastases compared with 23 matched normal breast tissues
Project description:Purpose Triple negative breast cancer (TNBC) is the most aggressive breast cancer subtype with no targeted treatment available. Our previous study identified 38 TNBC-specific genes with altered expression in tumour samples compared to normal samples. This study aimed to identify whether DNA methylation contributed to these gene expression changes in the same breast cancer cohort. Additionally, we aimed to identify a whole genome methylation profile that contributes to the progression from primary breast tumour to lymph node metastasis. Methods We used the DNA of 23 primary TNBC samples, 12 matched lymph node metastases, and 11 matched normal adjacent tissues to perform 450K Illumina methylation arrays. The results were validated in an independent cohort of 70 primary TNBC samples. Results The gene expression of 16/38 TNBC-specific genes was associated with significantly altered methylation. Furthermore, altered methylation of 18 genes associated with lymph node metastasis was identified and validated in an independent cohort. Additionally, novel methylation changes between primary tumours and lymph node metastases, as well as those associated with survival were identified. Conclusion This study has shown that DNA methylation plays an important role in altered gene expression patterns of TNBC-specific genes and is the first study to perform whole genome DNA methylation analysis that includes matched lymph node metastases in this breast cancer subtype. This novel insight into the progression of TNBC to secondary cancers may provide potential prognostic indicators for this hard-to-treat breast cancer subtype. study cohort
Project description:Triple-negative breast cancer (TNBC) is a heterogeneous subtype with varying disease outcomes. Tumor infiltrating lymphocytes (TILs) are frequent in TNBC and have been shown to correlate with outcome, suggesting an immunogenic component in this subtype. However, other factors, intrinsic to the cancer cells, may also influence outcome. To identify proteins and molecular pathways associated with recurrence in TNBC, 34 formalin-fixed paraffin-embedded (FFPE) primary TNBC tumors were investigated by global proteomic profiling using TMT-HILIC-LC-MS/MS. Approximately half of the patients were lymph node-negative and remained free of local or distant metastasis within 10 years follow-up, while the other half developed distant metastasis. Proteomic profiling identified >4000 proteins, of which 63 exhibited altered expression in primary tumors of recurrence versus recurrence-free patients. Importantly, down-regulation of proteins in the major histocompatibility complex (MHC) class I antigen presentation pathways were enriched, including TAP1, TAP2, CALR, HLA-A, ERAP1 and TAPBP, and were associated with significantly shorter recurrence-free and overall survival. In addition, proteins involved in cancer cell proliferation and growth, including GBP1, RAD23B, WARS and STAT1, also exhibited altered expression in primary tumors of recurrence versus recurrence-free patients. The association between the antigen-presentation pathway and outcome were validated in a second sample set of 10 primary TNBC tumors and corresponding metastases using proteomics and in a large public gene expression database of 249 TNBC and 580 basal-like breast cancer cases. Our study demonstrates that down-regulation of antigen presentation is a key mechanism for TNBC cells to avoid immune surveillance, allowing continued growth and spread.
Project description:Purpose Triple negative breast cancer (TNBC) is the most aggressive breast cancer subtype with no targeted treatment available. Our previous study identified 38 TNBC-specific genes with altered expression in tumour samples compared to normal samples. This study aimed to identify whether DNA methylation contributed to these gene expression changes in the same breast cancer cohort. Additionally, we aimed to identify a whole genome methylation profile that contributes to the progression from primary breast tumour to lymph node metastasis. Methods We used the DNA of 23 primary TNBC samples, 12 matched lymph node metastases, and 11 matched normal adjacent tissues to perform 450K Illumina methylation arrays. The results were validated in an independent cohort of 70 primary TNBC samples. Results The gene expression of 16/38 TNBC-specific genes was associated with significantly altered methylation. Furthermore, altered methylation of 18 genes associated with lymph node metastasis was identified and validated in an independent cohort. Additionally, novel methylation changes between primary tumours and lymph node metastases, as well as those associated with survival were identified. Conclusion This study has shown that DNA methylation plays an important role in altered gene expression patterns of TNBC-specific genes and is the first study to perform whole genome DNA methylation analysis that includes matched lymph node metastases in this breast cancer subtype. This novel insight into the progression of TNBC to secondary cancers may provide potential prognostic indicators for this hard-to-treat breast cancer subtype. Validation cohort (70 IDC TNBC samples)