Project description:Circulating tumour cells in women with advanced oestrogen-receptor (ER)-positive/human epidermal growth factor receptor 2 (HER2)-negative breast cancer acquire a HER2-positive subpopulation after multiple courses of therapy. In contrast to HER2-amplified primary breast cancer, which is highly sensitive to HER2-targeted therapy, the clinical significance of acquired HER2 heterogeneity during the evolution of metastatic breast cancer is unknown. Here we analyse circulating tumour cells from 19 women with ER+/HER2- primary tumours, 84% of whom had acquired circulating tumour cells expressing HER2. Cultured circulating tumour cells maintain discrete HER2+ and HER2- subpopulations: HER2+ circulating tumour cells are more proliferative but not addicted to HER2, consistent with activation of multiple signalling pathways; HER2- circulating tumour cells show activation of Notch and DNA damage pathways, exhibiting resistance to cytotoxic chemotherapy, but sensitivity to Notch inhibition. HER2+ and HER2- circulating tumour cells interconvert spontaneously, with cells of one phenotype producing daughters of the opposite within four cell doublings. Although HER2+ and HER2- circulating tumour cells have comparable tumour initiating potential, differential proliferation favours the HER2+ state, while oxidative stress or cytotoxic chemotherapy enhances transition to the HER2- phenotype. Simultaneous treatment with paclitaxel and Notch inhibitors achieves sustained suppression of tumorigenesis in orthotopic circulating tumour cell-derived tumour models. Together, these results point to distinct yet interconverting phenotypes within patient-derived circulating tumour cells, contributing to progression of breast cancer and acquisition of drug resistance.
Project description:Circulating tumour cells in women with advanced oestrogen-receptor (ER)-positive/human epidermal growth factor receptor 2 (HER2)-negative breast cancer acquire a HER2-positive subpopulation after multiple courses of therapy. In contrast to HER2-amplified primary breast cancer, which is highly sensitive to HER2-targeted therapy, the clinical significance of acquired HER2 heterogeneity during the evolution of metastatic breast cancer is unknown. Here we analyse circulating tumour cells from 19 women with ER+/HER2- primary tumours, 84% of whom had acquired circulating tumour cells expressing HER2. Cultured circulating tumour cells maintain discrete HER2+ and HER2- subpopulations: HER2+ circulating tumour cells are more proliferative but not addicted to HER2, consistent with activation of multiple signalling pathways; HER2- circulating tumour cells show activation of Notch and DNA damage pathways, exhibiting resistance to cytotoxic chemotherapy, but sensitivity to Notch inhibition. HER2+ and HER2- circulating tumour cells interconvert spontaneously, with cells of one phenotype producing daughters of the opposite within four cell doublings. Although HER2+ and HER2- circulating tumour cells have comparable tumour initiating potential, differential proliferation favours the HER2+ state, while oxidative stress or cytotoxic chemotherapy enhances transition to the HER2- phenotype. Simultaneous treatment with paclitaxel and Notch inhibitors achieves sustained suppression of tumorigenesis in orthotopic circulating tumour cell-derived tumour models. Together, these results point to distinct yet interconverting phenotypes within patient-derived circulating tumour cells, contributing to progression of breast cancer and acquisition of drug resistance. Seventy-four single candidate CTCs from two representative ER+/HER2- patients (BRx-42 and BRx-82) and 14 triple negative patients were isolated via micromanipulation and subjected to single-cell RNA-sequencing. Thirteen candidate CTCs expressed PTPRC at a level higher than 10 reads-per-million, so were deemed potential White Blood Cells and therefore dropped from further consideration. Expression profiles of CTCs expressing ERBB2 at a level greater than 10 RPM were compared with those expressing ERBB2 at a level less than 10 RPM.
Project description:Background MicroRNA expression is frequently dysregulated in cancer and it could be used potentially as a disease classifier and a prognostic tool in cancer. It has been reported that the cancer associated specific microRNAs were stably detected in blood. The objective of this study was to discover a panel of circulating microRNAs as potential ER+/HER2- breast cancer biomarkers. Methods We compared levels of circulating microRNAs in blood samples from 11 ER+/HER2- advanced breast cancer patients with age-matched 5 control subjects by using microarray-based expression profiling. We validated the level of microRNAs by real-time quantitative polymerase cycle reaction (RT-qPCR) in 40 control subjects, 180 early breast cancer patients (EBC), and 52 metastatic breast cancer patients (MBC). Then, we assessed the association between the levels of microRNA and clinical outcomes of ER+/HER2- metastatic breast cancer. Background MicroRNA expression is frequently dysregulated in cancer and it could be used potentially as a disease classifier and a prognostic tool in cancer. It has been reported that the cancer associated specific microRNAs were stably detected in blood. The objective of this study was to discover a panel of circulating microRNAs as potential ER+/HER2- breast cancer biomarkers. Methods We compared levels of circulating microRNAs in blood samples from 11 ER+/HER2- advanced breast cancer patients with age-matched 5 control subjects by using microarray-based expression profiling. We validated the level of microRNAs by real-time quantitative polymerase cycle reaction (RT-qPCR) in 40 control subjects, 180 early breast cancer patients (EBC), and 52 metastatic breast cancer patients (MBC). Then, we assessed the association between the levels of microRNA and clinical outcomes of ER+/HER2- metastatic breast cancer. Controls: 5 cases; ER +/HER2- breast cancer patients : 11 cases
Project description:By applying RNA-ISH and RNAseq to circulating tumor cells (CTCs), the study provides definitive evidence of epithelial to mesenchymal transition (EMT) across all histological types of breast cancer, identifying mediators such as FOXC1 and TGF-β signaling, and demonstrating dynamic treatment-associated changes in EMT within clusters of CTCs. Epithelial to mesenchymal transition (EMT) has been postulated to contribute to the migration and dissemination of cancer cells, but supporting histopathological evidence is limited. We used a microfluidic device to isolate circulating tumor cells (CTCs), combined with multiplex fluorescent RNA-in-situ hybridization (ISH) and RNA sequencing, to quantify and characterize EMT in breast cancer cells within the bloodstream. Whereas only rare (0.1-10%) cells in the primary tumor expressed both mesenchymal and epithelial markers, such biphenotypic as well as purely mesenchymal cells were enriched among CTCs, across all histological subtypes of breast cancer. In an index patient followed longitudinally, fluctuation in epithelial and mesenchymal states was observed as a function of initial response and subsequent resistance to therapy. Mesenchymal markers were predominant in clusters of tumor cells, many of which had adherent platelets. Finally, RNA sequencing of CTC clusters identified TGF-β and other EMT-related signatures, which were absent from more epithelial CTCs. FOXC1, a known regulator of EMT, was abundantly expressed in mesenchymal CTCs and was detectable within localized regions of the primary breast tumor. Together, these data support a role for EMT in the blood-borne dissemination of breast cancer and point to the dynamic nature of this cell fate change.
Project description:Background MicroRNA expression is frequently dysregulated in cancer and it could be used potentially as a disease classifier and a prognostic tool in cancer. It has been reported that the cancer associated specific microRNAs were stably detected in blood. The objective of this study was to discover a panel of circulating microRNAs as potential ER+/HER2- breast cancer biomarkers. Methods We compared levels of circulating microRNAs in blood samples from 11 ER+/HER2- advanced breast cancer patients with age-matched 5 control subjects by using microarray-based expression profiling. We validated the level of microRNAs by real-time quantitative polymerase cycle reaction (RT-qPCR) in 40 control subjects, 180 early breast cancer patients (EBC), and 52 metastatic breast cancer patients (MBC). Then, we assessed the association between the levels of microRNA and clinical outcomes of ER+/HER2- metastatic breast cancer. Background MicroRNA expression is frequently dysregulated in cancer and it could be used potentially as a disease classifier and a prognostic tool in cancer. It has been reported that the cancer associated specific microRNAs were stably detected in blood. The objective of this study was to discover a panel of circulating microRNAs as potential ER+/HER2- breast cancer biomarkers. Methods We compared levels of circulating microRNAs in blood samples from 11 ER+/HER2- advanced breast cancer patients with age-matched 5 control subjects by using microarray-based expression profiling. We validated the level of microRNAs by real-time quantitative polymerase cycle reaction (RT-qPCR) in 40 control subjects, 180 early breast cancer patients (EBC), and 52 metastatic breast cancer patients (MBC). Then, we assessed the association between the levels of microRNA and clinical outcomes of ER+/HER2- metastatic breast cancer.
Project description:Connexin 43 (Cx43) is a protein encoded by the GJA1 gene and is a component of cell membrane structures called gap junctions, which facilitate intercellular communication. Prior evidence indicates that elevated GJA1 expression in the HER2-positive (HER2+) subtype of breast cancer is associated with poor prognosis. Prior evidence also suggests that HER2+ breast cancers that have become refractory to HER2 targeted agents have a loss of Cx43 gap junction intercellular communication (GJIC). In this study, a Cx43 targeted agent called alpha-connexin carboxyl-terminal peptide (aCT1) is examined to determine whether GJIC can be rescued in refractory HER2+ breast cancer cells. A proposed mechanism of action for aCT1 is binding to the tight junction protein Zonal Occludens-1 (ZO-1). However, the true scope of activity for aCT1 has not been explored. In this study, proteomic analysis is used to determine the breadth of aCT1 interacting proteins. The NanoString nCounter Breast Cancer 360 panel was also used to examine the effect of aCT1 on cancer signaling in HER2+ breast cancer cells. Findings from this study show a dynamic range of binding partners for aCT1, many of which regulate gene expression and RNA biology. nCounter analysis shows that a number of pathways are significantly impacted by aCT1 including upregulation of apoptotic factors, leading to the prediction and demonstration that aCT1 can boost the cell death effects of cisplatin and lapatinib in HER2+ breast cancer cells that have become resistant to HER2 targeted agents.
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:HER2 is a transmembrane receptor tyrosine kinase, which plays a key role in breast cancer due to a common genomic amplification. It is used as a marker to stratify patients in the clinic and is targeted by a number of drugs including Trastuzumab and Lapatinib. HER2 has previously been shown to translocate to the nucleus. In this study, we have explored the properties of nuclear HER2 by analysing the binding of this protein to the chromatin in three breast cancer cell lines. We find genome-wide re-programming of HER2 binding after treatment with the growth factor EGF. Over 4,000 HER2 binding sites are found in all three breast cancer cell lines, and these occur near genes involved in protein kinase activity and signal transduction. HER2 was shown to co-localise at a subset of regions demarcated by H3K4me1, a hallmark of functional enhancer elements and HER2/H3K4me1 co-bound regions were enriched near EGF regulated genes providing evidence for their functional role as regulatory elements. A chromatin bound role for HER2 was verified by independent methods, including Proximity Ligation Assay (PLA), which confirmed a close association between HER2 and H3K4me1. Interestingly, HER2 bound to the ErbB2 gene itself indicating a potential self-regulatory mechanism for HER2. Mass spectrometry analysis of the chromatin bound HER2 complex identified EGFR and STAT3 as interacting partners. These findings reveal a global role for HER2 as a chromatin-associated factor that binds to enhancer elements to elicit direct gene expression events in breast cancer cells.
Project description:We have assayed differential miRNA expression between late stage (stage IV) metastatic Her2+ and Her2- breast cancer. 4 late stage metastatic Her2- samples were compared to 3 late stage metastatic Her2+ samples. There are 4 within array replicates for each sample.
Project description:Two TMT-6 plex experiments were performed to quantify two states of breast cancer circulating tumor cells (CTCs) from 3 patients. The data was acquired on an Orbitrap Fusion using the SPS-MS3 method.