ABSTRACT: Discordant cellular response to pre-surgical letrozole in bilateral synchronous ER+ breast cancers with a KRAS mutation or FGFR1 gene amplification
Project description:This clinical case resulted from an ongoing trial at Vanderbilt University and abroad where ER+ breast cancer patients are administered 2-3 weeks of aromatase inhibitor therapy leading up to definitive surgical resection of the tumor. In this case, we describe a study patient presenting with bilateral primary ER+ breast tumors. Short term hormonal therapy substantially reduced proliferation in one tumor, while the second was essentially unchanged. Extensive molecular and genetic workup of the two tumors yielded divergent lesions in the two tumors; an activating KRAS mutation in the responsive tumor, and an amplification of the FGFR1 locus in the treatment-refractory tumor. Surgical tumor specimens from ER+ breast cancer patient 7603 who was administered letrozole for 16 days leading up to definitive surgery were utilized for RNA extraction and hybridization to Affymetrix Gene expression microarrays.
Project description:This clinical case resulted from an ongoing trial at Vanderbilt University and abroad where ER+ breast cancer patients are administered 2-3 weeks of aromatase inhibitor therapy leading up to definitive surgical resection of the tumor. In this case, we describe a study patient presenting with bilateral primary ER+ breast tumors. Short term hormonal therapy substantially reduced proliferation in one tumor, while the second was essentially unchanged. Extensive molecular and genetic workup of the two tumors yielded divergent lesions in the two tumors; an activating KRAS mutation in the responsive tumor, and an amplification of the FGFR1 locus in the treatment-refractory tumor.
Project description:Multiple tumours from the same patient were analysed for copy number alterations to assess tumour clonality. Seventy-four tumours corresponding to 37 patients were stratified into four groups based on the anatomic location of the multiple breast cancers (ipsilateral or bilateral) and time interval between the diagnoses (synchronous or metachronous). Ipsilateral was defined as tumours occurring in the same breast while bilateral was defined as the occurrence of tumours in both breasts. Metachronicity was defined as a time interval greater than six months between the diagnoses of the first and second tumours, while synchronicity specified that the two tumours occurred concurrently (BM: bilateral-metachronous; BS: bilateral-synchronous; IM: ipsilateral-metachronous; IS: ipsilateral-synchronous).
Project description:The gene encoding fibroblast growth factor receptor 1 (FGFR1) amplification is associated with poor prognosis in estrogen receptor positive (ER+) breast cancer, and thus represents a potential therapeutic target. Fluorescent in situ hybridization (FISH) has been used as the gold standard methodology for detection of FGFR1 amplification, but it is a relatively long labor-intensive procedure and not efficient to process a large number of patient samples, especially formalin fixed paraffin embedded (FFPE) samples. This study sought to identify genes discriminative at the mRNA level for FGFR1 amplification and to construct a multi-gene test to facilitate efficient screening for FGFR1 amplified ER+ breast tumors.
Project description:Multiple tumours from the same patient were analysed for DNA methylation to assess tumour clonality. Seventy-four tumours corresponding to 37 patients were stratified into four groups based on the anatomic location of the multiple breast cancers (ipsilateral or bilateral) and time interval between the diagnoses (synchronous or metachronous). Ipsilateral was defined as tumours occurring in the same breast while bilateral was defined as the occurrence of tumours in both breasts. Metachronicity was defined as a time interval greater than six months between the diagnoses of the first and second tumours, while synchronicity specified that the two tumours occurred concurrently (BM: bilateral-metachronous; BS: bilateral-synchronous; IM: ipsilateral-metachronous; IS: ipsilateral-synchronous). A subset of 16 samples was randomly selected to represent each clinical group with four samples corresponding to two patients per group and analysed for DNA methylation using Illumina Infinium Human MethylationEPIC BeadChips.
Project description:Background: Up to 40% of patients with estrogen receptor positive (ER+) breast cancer experience treatment resistance and disease recurrence, often caused by the upregulation of growth factor receptors. Understanding the mechanisms of resistance, and the identification of novel therapeutic targets is, therefore, of vital importance if breast cancer prognosis is to be further improved. Fibroblast growth factor receptor 1 (FGFR1) is a potential driver of endocrine resistance; however, clinically successful attempts at targeting FGFR1 activity in breast cancer are rare and may result from an inability to correctly identify patients that could benefit from such treatment. The identification of additional genes associated with an FGFR1-mediated mechanism of resistance will provide a more precise classification scheme for FGFR1-dependency in breast cancer. Methods: Live cell imaging and RNA sequencing of ER+ breast cancer cell lines (CAMA1, T47D, tamoxifen resistant T47D) were used to investigate FGFR1-dependency in breast cancer, mechanisms of endocrine resistance and the effects of treatment with tamoxifen and erdafitinib. An FGFR1-amplified ER+ breast cancer patient-derived xenograft (PDX) model was used to assess the effects of targeting FGFR1 in vivo. Gene expression analysis of human breast cancer from The Cancer Genome Atlas (TCGA) was used for clinical validation. Results: We evaluated the effects of targeting FGFR1 in ER+/HER2- breast cancer with aberrant FGFR1 amplification and/or overexpression. We found that the FGFR tyrosine kinase inhibitor (TKI) erdafitinib inhibited cell proliferation of FGFR1-amplified CAMA1 cells in vitro. Additionally, erdafitinib significantly enhanced the anti-proliferative effect of 4-hydroxytamoxifen (4-OHT) and its anti-tumor effect was also demonstrated in vivo. Further, we demonstrated that the proliferation of FGFR1-overexpressing tamoxifen-resistant T47D (TR-T47D) cells is dependent on FGFR1 activity. Moreover, these TR-T47D cells are re-sensitized to tamoxifen upon treatment with erdafitinib. Finally, we found that upregulation of genes related to epithelial-mesenchymal-transition (EMT) correlates with FGFR1 overexpression, and is reversed by FGFR inhibition. Conclusions: In this study we demonstrated that targeting FGFR1 in ER+/HER2- breast cancer with aberrant FGFR1 activity has the potential to inhibit tumor growth and to re-sensitize resistant tumors to tamoxifen. Furthermore, we identified a functional relationship between EMT, FGFR activity and endocrine resistance in breast tumorigenesis.
Project description:Biopsies were collected from post-menopausal women with ER+ HER2- breast cancer who were subsequently treated with either letrozole or letrozole plus bevacizumab.
Project description:A large-panel gene expression analysis was conducted to identify biomarkers associated with the effectiveness of adding palbociclib to letrozole Cyclin-dependent kinase 4/6 (CDK4/6) inhibitors have demonstrated significant activity in estrogen receptor-positive/human epidermal growth factor receptor 2-negative (ER+/HER2-) advanced breast cancer. Further biomarkers to refine the population beyond ER+/HER2- that benefits remain to be identified. We performed a comprehensive biomarker analysis using patient tissues from PALOMA-2, a randomized phase 3 study of palbociclib-letrozole versus placebo-letrozole, to determine markers of sensitivity and resistance to the combination.
Project description:Fibroblast growth factor receptor 1 (FGFR1) is a heavily N-glycosylated cell surface receptor tyrosine kinase, which in conjunction with fibroblast growth factors (FGFs) transmits signals through the plasma membrane. The balanced FGF/FGFR1 signaling is crucial for the development and homeostasis of human body and aberrant FGFR1 is often observed in various cancers. Besides predominant localization to the plasma membrane, FGFR1 was also detected inside cells, mainly in the nuclear lumen, where it modulates gene expression. However, the exact mechanism of FGFR1 nuclear transport is still unknown. In this study, we generated a glycosylation-free mutant of FGFR1, FGFR1.GF, and demonstrate that it is primarily localized to the nuclear envelope. We show that reintroduction of N-glycans in the D3 domain cannot redirect FGFR1 to the plasma membrane nor exclude the receptor from the nuclear envelope. Reestablishment of N-glycans of the D2 domain largely inhibits FGFR1 accumulation in the nuclear envelope, but receptor still accumulates inside the cell, mainly in the ER. Only the simultaneous presence of N-glycans of the D2 and D3 domains of FGFR1 supports the efficient transport of FGFR1 to the plasma membrane. Intracellular FGFR1.GF displays high level of autoactivation, suggesting the presence of nuclear FGFR1 signaling that is FGF independent. Using mass spectrometry and proximity ligation assay we identified novel binding partners of the nuclear envelope-localized FGFR1, providing insights into its cellular functions. Taken together, our data define N-glycosylation of FGFR1 as a significant regulator of FGFR1 kinase activity, and most importantly a switchable signal for FGFR1 trafficking between the nuclear envelope and the plasma membrane, which, due to the spatial restrictions, shapes the FGFR1 interactome and cellular function.