Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0006142 (breast cancer)
 160,383 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Breast cancer cells pose a difficult target for detection due to their lack of tumor specific markers. Small numbers of metastatic cells circulate through the blood and reach target organs, but current methods are presently not sensitive enough to allow for early detection. Our goal is to develop a method for specific and sensitive detection for breast cancer tumor cells by using cell enrichment coupled to RT-PCR with selective primer pairs. Fifty million normal donor mononuclear cells (NDMNC) were spiked with serial dilutions of a breast cancer cell line, positively selected for surface expression of the epithelial cell adhesion molecule (EPCAM) with anti-Ber-EP4 mAb. Total RNA was isolated and the cDNA was transcribed and measured by quantitative PCR for cytokeratin 19 (CK19), epidermal growth factor receptor (EGF-R), and beta-2-microglobulin (beta2M) transcripts using specific hybridization probes with the LightCycler System. A sensitivity of 1 tumor cell in 5 million NDMNC was consistently achieved with a metastatic breast cancer cell line with target primer sets for CK19 and EGF-R. Less, but appreciable sensitivity was achieved by spiking NDMNC with other breast cancer cells. Detection of both gene targets ranged between 1 in 5,000 to 5 million cells. The method described, a cell enrichment procedure and RT-PCR using specific hybridization probes (spanning introns and hybridizing to areas that discriminate transcribed pseudogenes), results in increased sensitivity while decreasing false positives above those methods previously reported. This general approach may have wide applicability to increasing sensitivity of minimal residual disease detection in other cancers.
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PMID:Minimal residual disease detection in breast cancer: improved sensitivity using cytokeratin 19 and epidermal growth factor receptor RT-PCR. 1501 Aug 23

EpCAM (epithelial cell adhesion molecule) is a cell surface molecule that is known to be highly expressed in colon and other epithelial carcinomas. EpCAM is involved in cell-to-cell adhesion and has been the target of antibody therapy in several clinical trials. To assess the value of EpCAM as a novel target for breast cancer gene therapy, we performed real-time reverse transcription-PCR to quantify the level of EpCAM mRNA expression in normal breast tissue and primary and metastatic breast cancers. We found that EpCAM is overexpressed 100- to 1000-fold in primary and metastatic breast cancer. Silencing EpCAM gene expression with EpCAM short interfering RNA (siRNA) resulted in a 35-80% decrease in the rate of cell proliferation in four different breast cancer cell lines. EpCAM siRNA treatment decreased cell migration by 91.8% and cell invasion by 96.4% in the breast cancer cell line MDA-MB-231 in vitro. EpCAM siRNA treatment was also associated with an increase in the detergent-insoluble protein fraction of E-cadherin, alpha-catenin, and beta-catenin, consistent with the known biology of EpCAM as a regulator of cell adhesion. Our hypothesis is that modulation of EpCAM expression can affect cell migration, invasion, and proliferation by enhancing E-cadherin-mediated cell-to-cell adhesion. These data provide compelling evidence that EpCAM is a potential novel target for breast cancer gene therapy and offer insights into the mechanisms associated with EpCAM gene silencing.
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PMID:EpCAM is overexpressed in breast cancer and is a potential target for breast cancer gene therapy. 1531 25

Disseminated tumor cells (DTC) in bone marrow are independently related to poor outcome in patients with breast cancer. Phenotypic characterization of DTC may be useful to improve evaluation of the metastasizing potential of DTC and also to more accurately target aggressive tumor cells. DTC were screened in bone marrow aspirates from breast cancer patients by immunocytochemistry with an anticytokeratin (anti-CK) antibody (A45B/B3). Because the cell permeabilization and fixation required for intracellular CK staining is deleterious for mRNA, we used microaspiration to isolate single tumor cells stained with a monoclonal antibody directed against a membrane epitope, epithelial cell adhesion molecule (EpCAM), in CK-positive cases. Urokinase-type plasminogen activator receptor (uPAR) was quantified by real-time quantitative RT-PCR. The SKBR3 human breast cancer cell line was used to calibrate RT-PCR. A linear relationship was observed between the cycle threshold (Ct) of uPAR and 18S gene expression and SKBR3 cells spiked (1, 3, 7, 10 and 20) in control patient bone marrow. EpCAM-positive cells were aspirated in 21 out of 25 bone marrow specimens from breast cancer patients with CK-positive cells and uPAR mRNA expression was determined in 16 cases. A high level of uPAR mRNA in DTC was detected in 8 out of 16 patients (50%) and was associated with a more aggressive primary tumor phenotype (estrogen receptor [ER]-negative, progesterone receptor [PR]-negative or HER2-positive) (p = 0.01). We demonstrated that real-time quantitative RT-PCR was reliably adapted to phenotype analysis of isolated micrometastatic cells. A larger study would be useful to confirm the importance of uPAR to define higher risk subgroups of breast cancer patients with micrometastatic disease.
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PMID:Real-time quantitative PCR determination of urokinase-type plasminogen activator receptor (uPAR) expression of isolated micrometastatic cells from bone marrow of breast cancer patients. 1554 15

MT201 is a fully human monoclonal IgG1 antibody with moderate affinity for epithelial cell adhesion molecule (Ep-CAM) being clinically developed for the treatment of carcinomas. Like many other clinically validated IgG1 monoclonal antibodies, MT201 primarily acts by antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC). Here, we analysed ADCC and CDC induced by MT201 and, as reference, trastuzumab against a panel of nine human breast cancer cell lines expressing distinct surface levels of Ep-CAM and human epithelial growth factor receptor type 2 antigen. Maximal cell lysis by ADCC by MT201 and trastuzumab in the presence of peripheral mononuclear cells did not significantly differ when averaged over the nine cell lines, but showed marked differences with respect to individual cell lines. The extent of cell lysis at intermediate surface target density was highly variable, suggesting a dominant influence of other susceptibility factors. Only one breast cancer cell line was eliminated via CDC, but only by MT201. Resistance to CDC appeared to correlate with high expression levels of complement resistance factors. Our present data as well as recent data on the prevalence and prognostic relevance of Ep-CAM expression in metastatic breast cancer suggest that Ep-CAM-specific monoclonal IgG1 antibodies may have a significant therapeutic potential in the treatment of breast cancer.
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PMID:Cellular and complement-dependent cytotoxicity of Ep-CAM-specific monoclonal antibody MT201 against breast cancer cell lines. 1565 55

The epithelial cell adhesion molecule, EpCAM, is a transmembrane glycoprotein associated with both benign and malignant proliferation. In cancer cells, expression levels of this tumour-associated antigen correlate positively with the grade of dysplasia and are also a negative prognostic factor for breast cancer patients. De novo expression of EpCAM resulted in the rapid upregulation of the proto-oncogene c-Myc along with enhanced cell proliferation and metabolism. Here, we analyzed the effects of EpCAM onto the proteome of epithelial cells. The epidermal fatty acid binding protein, E-FABP, was identified as a new EpCAM-regulated protein. E-FABP is a major target of c-Myc and was rapidly upregulated upon induction of EpCAM. Additionally, E-FABP levels correlated with the amount of EpCAM in permanent squamous cell carcinoma lines and in vivo in primary head and neck carcinomas. Taken together, these results provide further evidence for the direct involvement of EpCAM in signalling processes, gene regulation, and cellular metabolism supporting its important role in tumour biology.
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PMID:The tumour-associated antigen EpCAM upregulates the fatty acid binding protein E-FABP. 1592 67

When cells transform, phenotypic and genetic profiles can be dramatically altered. Nevertheless, a recent report identifying IgG in breast cancer cells was unexpected, revealing differentiation features normally associated with B lymphocytes. To extend these findings, we focused on immunoglobulin variable (V) region gene analysis using well-defined breast cancer cell lines expressing the epithelial marker, epithelial cell adhesion molecule (EpCAM). V(H) gene transcripts were identifiable by nested reverse transcription-PCR either as single or dual V, diversity (D), and joining (J) rearrangements in four of six lines, most being potentially functional. V(D)J transcripts were observed in sequential cultures, indicating stable expression. To exclude coexisting lymphocytes, each cell line was shown to be EBV negative, with CD19/CD20 and cytoplasmic/surface immunoglobulin also absent by flow cytometry. Identified V(H) transcripts were then sought in individual tumor cells, isolated as EpCAM+ single cells by flow cytometry. Importantly, in three of three selected cell lines, V(H) genes were identifiable in a significant fraction (approximately 32%) of single cells. In five of six identified V(H) genes, somatic mutations were apparent with no intraclonal variation, indicating cessation of mutational activity. V(H) transcripts were pre- and post-isotype switch, with activation of switch events evident from expressed germ-line switch transcripts in two of six lines. Strikingly, six of six cell lines expressed activation-induced cytidine deaminase (AID) essential for mutational and switch activity. These data suggest either a de novo rearrangement and modification of V(H) genes in epithelial tumor cells or assimilation of lymphocyte-derived chromatin. Constitutive AID activation in malignant epithelial cells further raises a potential for inducing aberrant mutational activity.
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PMID:Immunoglobulin heavy chain locus events and expression of activation-induced cytidine deaminase in epithelial breast cancer cell lines. 1661 18

The development of distant metastases is the major cause of death from breast cancer. In order to predict and prevent tumour spreading, many attempts are being made to detect small numbers of tumour cells that have shed from the primary lesions and have moved to lymph nodes, blood or bone marrow. This article presents the advantages and the limitations of techniques used for disseminated tumour cells (DTC) detection. DTC markers are listed and the most currently used of them (KRT19, CEACAM5, TACSTD1, MUC1, EGFR, ERBB2, SCGB2A2, SCGB2A1, SCGB1D2, PIP, SBEM, TFF1, TFF3, ANKRD30A, SPDEF, ESR1, SERPINB5 and GABRP) are discussed, notably on the basis of recent data on breast tumour portraits (luminal epithelial-like, basal/myoepithelial-like and ERBB2). The significance of DTC for the prognosis and prediction of response to therapy is examined. DTC viability, the notion of cell dormancy and the concept of breast cancer stem cells are also discussed.
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PMID:Significance, detection and markers of disseminated breast cancer cells. 1715 53

EpCAM (CD326) is one of the most frequently and highly expressed tumor-associated antigens known and recently has also been found on cancer stem cells derived from human breast, colon, prostate, and pancreas tumors. However, like many other tumor-associated antigens used for antibody-based immunotherapeutic approaches, EpCAM is expressed on normal tissues including epithelia of pancreas, colon, lung, bile ducts, and breast. To assess the therapeutic window of an EpCAM/CD3-bispecific single-chain antibody construct of the bispecific T-cell engager (BiTE) class, we constructed murine surrogate of MT110 (muS110) from single-chain antibodies specific for murine EpCAM and CD3 antigens. Immunhistochemical analysis showed that, with minor differences, the expression of EpCAM protein on a large variety of tissues from man and mouse was similar with respect to distribution and level. MuS110 exhibited significant antitumor activity at as low as 5 microg/kg in both syngeneic 4T1 orthotopic breast cancer and CT-26 lung cancer mouse models. Dosing of muS110 for several weeks up to 400 microg/kg by intraanimal dose escalation was still tolerated, indicating existence of a significant therapeutic window for an EpCAM-specific BiTE antibody in mice. MuS110 was found to have similar in vitro characteristics and in vivo antitumor activity as MT110, a human EpCAM/human CD3-bispecific BiTE antibody that currently is in formal preclinical development.
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PMID:Therapeutic window of MuS110, a single-chain antibody construct bispecific for murine EpCAM and murine CD3. 1817 6

We designed a new efficient and reliable immunosensor and demonstrated its analytic performance to capture breast cancer MCF7 and T47D cells, under laminar flow, onto antibody-coated long alkylsilane self-assembled monolayers (SAMs) in a parallel plate flow chamber. The surface floor of the laminar flow chamber was grafted with an amino-terminated long alkyl chain spacer, 21-aminohenicosyl trichlorosilane (AHTS) followed by tethering a specific monoclonal antibody directed against the human epithelial cell adhesion molecule (EpCAM) antigen, which is overexpressed in primary breast cancer. Properties of the AHTS- and antibody-grafted surface floor were compared to that of surface floors coated with the short alkyl spacers 3-glycidoxy-propyl trimethoxysilane (GPTS) or 3-aminopropyl triethoxysilane (APTES) and antibodies. A theoretical model was constructed according to the geometry of the flow chamber in order to calculate the trajectories that would use cell flows. Cell capture experiments demonstrated that cell immobilization was optimized throughout the whole flow chamber. High cell capture was yielded on antibody-tethered long alkyl AHTS surface. This new procedure offers multiple advantages: a versatile tool readily applied to a panel of purified antibodies, an enrichment of cell immobilization using repetitive cell flow, and a stable capturing surface suitable for long term storage and handling.
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PMID:A new immunosensor for breast cancer cell detection using antibody-coated long alkylsilane self-assembled monolayers in a parallel plate flow chamber. 1854

A novel microfluidic device that can selectively and specifically isolate exceedingly small numbers of circulating tumor cells (CTCs) through a monoclonal antibody (mAB) mediated process by sampling large input volumes (>/=1 mL) of whole blood directly in short time periods (<37 min) was demonstrated. The CTCs were concentrated into small volumes (190 nL), and the number of cells captured was read without labeling using an integrated conductivity sensor following release from the capture surface. The microfluidic device contained a series (51) of high-aspect ratio microchannels (35 mum width x 150 mum depth) that were replicated in poly(methyl methacrylate), PMMA, from a metal mold master. The microchannel walls were covalently decorated with mABs directed against breast cancer cells overexpressing the epithelial cell adhesion molecule (EpCAM). This microfluidic device could accept inputs of whole blood, and its CTC capture efficiency was made highly quantitative (>97%) by designing capture channels with the appropriate widths and heights. The isolated CTCs were readily released from the mAB capturing surface using trypsin. The released CTCs were then enumerated on-device using a novel, label-free solution conductivity route capable of detecting single tumor cells traveling through the detection electrodes. The conductivity readout provided near 100% detection efficiency and exquisite specificity for CTCs due to scaling factors and the nonoptimal electrical properties of potential interferences (erythrocytes or leukocytes). The simplicity in manufacturing the device and its ease of operation make it attractive for clinical applications requiring one-time use operation.
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PMID:Highly efficient circulating tumor cell isolation from whole blood and label-free enumeration using polymer-based microfluidics with an integrated conductivity sensor. 1855 14


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