Breast Cancer Susceptibility Gene 1 mRNA Research Articles

Expression of HER2 and BRCA1 Correlates with Prognosis in Patients with Breast Cancer After Radiotherapy: A Case-Control Study.

Background: This study aims to explore the associations of human epidermal growth factor receptor 2 (HER2) and breast cancer susceptibility gene 1 (BRCA1) expression levels with prognosis and radiation sensitivity in patients with breast cancer. Materials and Methods: Breast cancer tissues, adjacent normal breast tissues, and benign breast lesions were initially obtained from 256 breast cancer patients as well as an additional 245 patients with breast lesions. Reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR) was conducted to assess the expression of HER2 and BRCA1 in the collected tissues. Immunohistochemistry was performed to examine HER2 and BRCA1-positive expression levels in the tissues. The relationship between HER2 and BRCA1 expression levels and radiation sensitivity as well breast cancer prognosis was assessed by the Spearman correlation analysis and Kaplan-Meier survival analysis. Results: Compared with adjacent normal breast tissues and benign breast lesions, the breast cancer tissues exhibited high expression of HER2 mRNA and protein, and low expression of BRCA1 mRNA and protein. Patients with positive HER2 expression had a significantly shorter survival time, and survival time of patients with positive BRCA1 expression was markedly longer, which were consistent with RT-qPCR results. After radiotherapy, the local failure rate of HER2-positive patients was higher than that of the negative ones, while that of BRCA1-positive patients was lower than that of the negative ones. Conclusions: This study suggested that breast cancer patients with high HER2 expression and low BRCA1 expression were less sensitive to radiotherapy with poor prognosis in breast cancer.

Abstract 4846: Targeting BRCA1-mutated cancer cells with elesclomol

Abstract The breast cancer susceptibility gene 1 (BRCA1) encodes a tumor-suppressor protein that maintains genetic stability through DNA damage response pathways. Specifically, BRCA1 has a well-established role in double-strand DNA break repair, and emerging evidence supports a role for BRCA1 in repair of oxidative DNA damage via the base-excision repair (BER) pathway. We and others have shown that cells with mutant/deficient BRCA1 harbor defective BER of oxidative DNA damage. Interestingly, defective BER of oxidative DNA damage in breast cancer cells rendered sensitivity to elesclomol, an experimental therapeutic that induces reactive oxygen species to levels beyond a viable threshold. Given that BRCA1-mutated cancers associate with a poor prognosis and are in need of targeted treatment options, we hypothesized that breast or ovarian cancer cells with mutant BRCA1 would exhibit selective sensitivity to elesclomol or treatment regimens containing elesclomol. First, we determined the effect of BRCA1 on the cellular response to oxidative stress and elesclomol using human ovarian cancer cells isogenic for BRCA1. Compared to mutant BRCA1 cells (UWB1.289), wild-type BRCA1 cells (UWB1.289+BRCA1) produced significantly greater levels of BRCA1 mRNA (p=0.009), expressed markedly higher levels of BRCA1 protein in the nucleus, and showed significantly greater sensitivity to hydrogen peroxide (p=0.002) as evidenced by RTqPCR, Western blot analysis, and MTT assay, respectively. Importantly, mutant BRCA1 cells displayed an approximate 100-fold greater sensitivity to elesclomol compared to wild-type BRCA1 cells as determined by MTT assay. These data suggest that the oxidative stress induced by elesclomol may be used to selectively target cancer cells with mutant BRCA1 due to their defective BER phenotype. We next asked whether elesclomol may be combined with other agents used clinically or experimentally for the treatment of BRCA1-mutated cancers, including standard chemotherapy drugs and PARP inhibitors. Elesclomol exhibited synergistic sensitivity when combined with DNA-damaging agents, including doxorubicin or cisplatin, in breast cancer cells with mutant BRCA1 (SUM149) as determined by combination index and isobologram analysis. On the other hand, a synergistic effect was not observed with the anti-microtubule agent paclitaxel, which is consistent with a phase III study that evaluated this combination for the treatment of advanced melanoma. However, elesclomol in combination with PARP inhibitors, including rucaparib or talazoparib, indeed showed synergism in breast cancer cells with mutant BRCA1. These data suggest that elesclomol may be used in combination with other anticancer agents to further exploit defects in DNA repair due to mutant BRCA1. In conclusion, elesclomol may be explored as a novel component of treatment regimens for targeting BRCA1-mutated breast and ovarian cancers. Citation Format: Maria Kammire, Emily Fannin, James M. Ford, Elizabeth Alli. Targeting BRCA1-mutated cancer cells with elesclomol [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4846.

Semi-Automatic Quantification Of mRNA Expression In Whole-Slide Tissue Images

Introduction/ Background For complex diseases, commercially available anti- bodies directed again specific protein sometimes lack the specificity required for clinical purpose. Therefore, novel techniques have been proposed recently to better assess the expression status of molecules at the mRNA level, e.g. by in situ hybridization. With such a technique, single-molecule signals can then be quantified on a cell-by-cell basis in whole tissue slides. However, highly heterogeneous expression of mRNA is often observed at the tissue level, requiring the development of accurate and reproducible quantification methods. Aims In this work, our aim is to propose and evaluate a methodology for the quantification of mRNA expression in digital slides to help biomedical researchers to analyze their large-scale imaging data. In particular, we will work on a dataset of breast cancer tissue samples and evaluate the accuracy of such a methodology to quantify Breast cancer susceptibility gene 1 (BRCA1) mRNA expression levels. BRCA1 is a tumor suppressor gene associated with the triple negative breast cancer (TNBC) subtype. An accurate technique to determine BRCA1 protein tumoral expression status in TNBC would allow for informed decision and choosing adapted treatments. Methods D a t a: To design and evaluate our methodology, we use the data from [1]. In that study, the BRCA1 mRNA expression was assessed by in situ hybridization using RNAscope technology [2] (ACD-Bioke) for formalin-fixed, paraffin-embedded tissue samples. 88 glass slides were scanned (Hamamatsu, 40X, 0.23µm/pixel) and transferred on a Cytomine server (h t tp://www.cytomine.be/) [3]. These slides correspond to 62 tumours (TNBC subtype). Using Cytomine web manual annotation tools, a total of more than 200 regions of interest were manually drawn by an expert in these whole-slide images. Then, independent assessment was performed by two observers in these ROI: they manually draw point annotations corresponding to tens of thousands of BRCA1 mRNA expression signals. Algorithms: We have developed the Icytomine plugin to communicate between Icy and Cytomine. It allows the importation of the subtumor images at a desired resolution and the expert annotations from Cytomine and the exportation of detection results from Icy software ( http://icy.bioim ageanalysis.org) [4]. In order to quantify mRNA signals, we combined several image processing routines in the Icy. Our workflow is composed of three steps: 1) color deconvolution [5] to extract the dark brown staining, 2) detection of spots based on undecimated wavelet transform [6], 3) post-processing to remove artifacts based on size, shape and color features. This transform is fast and ideal for representing isotropic objects. We will use a colocalisation coefficient to quantify the concordance between the experts. For a purpose of automation, we use scripts and protocols of Icy. Results An illustration of our results is given in F ig ure Our ongoing large-scale empirical study stresses the need for more confident ground-truths hence more robust algorithms. Interestingly, our current strategy detects accurately spot locations. We believe it will help us to create a larger ground-truth dataset using expert proofreading. We will report at the conference our best quantitative results. Overall, we believe that our approach will speedup in a confident way the quantification of mRNA signals in whole-slide tissue samples.

BRCA1 germline mutation and glioblastoma development: report of cases

BackgroundGermline mutations in breast cancer susceptibility gene 1 (BRCA1) increase the risk of breast and ovarian cancers. However, no association between BRCA1 germline mutation and glioblastoma malignancy has ever been highlighted.Here we report two cases of BRCA1 mutated patients who developed a glioblastoma multiform (GBM).Cases presentationTwo patients diagnosed with triple negative breast cancer (TNBC) were screened for BRCA1 germline mutation. They both carried a pathogenic mutation introducing a premature STOP codon in the exon 11 of the BRCA1 gene. Few years later, both patients developed a glioblastoma and a second breast cancer. In an attempt to clarify the role played by a mutated BRCA1 allele in the GBM development, we investigated the BRCA1 mRNA and protein expression in breast and glioblastoma tumours for both patients. The promoter methylation status of this gene was also tested by methylation specific PCR as BRCA1 expression is also known to be lost by this mechanism in some sporadic breast cancers.ConclusionOur data show that BRCA1 expression is maintained in glioblastoma at the protein and the mRNA levels, suggesting that loss of heterozygosity (LOH) did not occur in these cases. The protein expression is tenfold higher in the glioblastoma of patient 1 than in her first breast carcinoma, and twice higher in patient 2. In agreement with the high protein expression level in the GBM, BRCA1 promoter methylation was not observed in these tumours.In these two cases, despite of a BRCA1 pathogenic germline mutation, the tumour-suppressor protein expression is maintained in GBM, suggesting that the BRCA1 mutation is not instrumental for the GBM development.

Clinicopathological Significance of BRCA1 Promoter Hypermethylation in Thai Breast Cancer Patients

Breast cancer susceptibility gene 1 (BRCA1), mapped on chromosome 17q21, is implicated in the mechanisms of cellular DNA repair. Inactivation of this gene is involved in the development of many human cancers, including breast cancer. This study aimed to investigate the prognostic value of BRCA1 promoter hypermethylation and expression in breast cancer cases. Sixty-one breast cancers were examined for BRCA1 hypermethylation by methylation-specific polymerase chain reaction (PCR), and 45 paired normal breast tissues were analyzed for altered BRCA1 mRNA levels by quantitative real-time reverse transcription-polymerase chain reaction (qRT- PCR). Aberrant methylation status in BRCA1 was detected in 15 of 61 cases (24.6%), while reduced expression was found in 7 of 45 (15.6%). BRCA1 hypermethylation was statistically associated with tumor grade III (p=0.04), a high frequency of stage IIB (p=0.02), and triple-negative phenotype (OR= 3.64, 95%CI =1.1-12.3, p=0.03). Our findings indicated that BRCA1 promoter hypermethylation is a useful prognostic marker for breast cancer.

Cinnamaldehyde/chemotherapeutic agents interaction and drug-metabolizing genes in colorectal cancer

Cinnamaldehyde is an active monomer isolated from the stem bark of Cinnamomum cassia, a traditional oriental medicinal herb, which is known to possess marked antitumor effects in vitro and in vivo. The aim of the present study was to examine the potential advantages of using cinnamaldehyde in combination with chemotherapeutic agents commonly used in colorectal carcinoma (CRC) therapy, as well as to investigate the effect of cinnamaldehyde on chemotherapeutic-associated gene expression. The synergistic interaction of cinnamaldehyde and chemotherapeutic agents on human CRC HT-29 and LoVo cells was evaluated using the combination index (CI) method. The double staining with Annexin V conjugated to fluorescein-isothiocyanate and phosphatidylserine was employed for apoptosis detection. The expression of drug-metabolizing genes, including excision repair cross‑complementing 1 (ERCC1), orotate phosphoribosyltransferase (OPRT), thymidylate synthase (TS), breast cancer susceptibility gene 1 (BRCA1) and topoisomerase 1 (TOPO1), all in HT-29 and LoVo cells, with or without the addition of cinnamaldehyde, was examined by quantitative polymerase chain reaction (PCR). Cinnamaldehyde had a synergistic effect on the chemotherapeutic agents cytotoxicity in HT-29 and LoVo cells. In addition, cinnamaldehyde suppressed BRCA1, TOPO1, ERCC1 and TS mRNA expression, except for OPRT expression, which was markedly upregulated. Our findings indicate that cinnamaldehyde appears to be a promising candidate as an adjuvant in combination therapy with 5-fluorouracil (5-FU) and oxaliplatin (OXA), two chemotherapeutic agents used in CRC treatment. The possible mechanisms of its action may involve the regulation of drug‑metabolizing genes.

BRCA1 and ERCC1mRNA levels are associated with lymph node metastasis in Chinese patients with colorectal cancer

BackgroundAlthough both excision repair cross-complementing group 1 (ERCC1) and breast cancer susceptibility gene 1 (BRCA1) can be effective biomarkers for chemosensitivity in primary malignant tumors, their applicability to metastases is poorly understood. Here, ERCC1 and BRCA1, which are linked to lymph node metastasis (LNM) in colorectal cancer (CRC), were evaluated in primary CRC samples from Chinese patients with LNM (LNM CRC) or without LNM (non-LNM CRC). mRNA levels of ERCC1 and BRCA1 in CRC samples, and their relationships to primary CRC and LNM, were also examined.MethodsDifferences in BRCA1 and ERCC1 gene expression between primary CRC with or without LNM were assessed in CRC samples from 120 Chinese patients, using real-time polymerase chain reaction. Relationships between ERCC1 and BRCA1 expression and clinicopathological parameters and prognoses were also examined.ResultsERCC1 and BRCA1 were significantly down-regulated in LNM CRC compared with non-LNM CRC. Down-expression of ERCC1 and BRCA1 was significantly associated with LNM (P < 0.001), advanced TNM stage (P < 0.001), and decreased 5-year overall survival rate (P < 0.001). Univariate and multivariate analyses showed ERCC1 and BRCA1 expression as independent predictors of recurrence and survival in CRC patients (P < 0.05).ConclusionsERCC1 and BRCA1 mRNA expression levels correlate inversely to CRC metastasis. ERCC1 and BRCA1 might serve as biomarkers for LNM and as prognostic indicators for CRC; their down-expressions are predictors of poor outcome in CRC patients.

BRCA1 mRNA Expression as a Predictive and Prognostic Marker in Advanced Esophageal Squamous Cell Carcinoma Treated with Cisplatin- or Docetaxel-Based Chemotherapy/Chemoradiotherapy

BackgroundThe molecular backgrounds that determine therapeutic effectiveness in esophageal cancer remain largely unknown. Breast cancer susceptibility gene 1 (BRCA1) expression has been found to switch the response to cisplatin- or paclitaxel-based chemotherapy. It remains unclear how variations in BRCA1 expression influence clinical outcomes in esophageal cancer.Patients and MethodsQuantitative real-time polymerase chain reaction (qPCR) was performed to examine BRCA1 mRNA expressions in paraffin-embedded specimens from 144 patients with advanced or metastatic esophageal squamous cell carcinoma who received cisplatin- or docetaxel-based first-line treatments.ResultsLow BRCA1 mRNA expression correlated with increased response rate (RR; P = 0.025 and 0.017, respectively) and median overall survival (mOS; P = 0.002 and P<0.001, respectively) in cisplatin-based chemotherapy or chemoradiotherapy group and also correlated with decreased RR (P = 0.017 and 0.024, respectively) and mOS (both P<0.001) in docetaxel-based chemotherapy or chemoradiotherapy group. Multivariate analysis revealed that low BRCA1 expression was an independent prognostic factor in cisplatin-based chemotherapy (HR 0.29; 95%CI 0.12–0.71; P = 0.007) or chemoradiotherapy (HR 0.12; 95%CI 0.04–0.37; P<0.001) group and higher risk for mortality in docetaxel-based chemotherapy (HR 5.02; 95%CI 2.05–12.28; P<0.001) or chemoradiotherapy (HR 7.02; 95%CI 2.37–27.77; P<0.001) group.ConclusionsBRCA1 mRNA expression could be used as a predictive and prognostic marker in esophageal cancer who underwent first-line cisplatin- or docetaxel-based treatments.

686P - Overall Survival (OS) to First- and Second-Line Chemotherapy Associated with Mrna Expression of Multiple Myeloma Set (MMSET) Domain, P53-Binding Protein 1 (53bp1) and Breast Cancer Susceptibility Gene 1 (BRCA1) in advanced Gastric Cancer Patients (P)

ABSTRACT Background Low BRCA1 expression enhances sensitivity to platinum, while high levels increase sensitivity to taxanes (Quinn et al. Cancer Res 2003). In response to cisplatin-induced DNA double strand breaks (DSBs), MDC1 binds to γH2AX, promoting DSB repair by 53BP1 and BRCA1. MMSET is required for the accretion of 53BP1, PIAS4 and Ubc9 to DSB sites. We hypothesized that the mRNA expression of these components of the MDC1-MMSET-53BP1 pathway could impact the predictive model based on BRCA1 mRNA expression (Wei et al. JNCI 2011). Methods Tumor samples were obtained from 132 advanced gastric cancer p treated with first-line FOLFOX, 58 of whom also received second-line docetaxel. mRNA expression of MDC1, MMSET, 53BP1, PIAS4, Ubc9 and BRCA1 was analyzed by real-time PCR. Results A close correlation was found between MMSET and BRCA1 (r = 0.28; P = 0.002), 53BP1 (r = 0.54; p Conclusions Longer OS to FOLFOX was associated with low levels of both MMSET and 53BP1, while longer OS to second-line docetaxel was associated with high levels of both MMSET and BRCA1. MMSET, together with 53BP1 or BRCA1 can be useful for customizing chemotherapy in advanced gastric cancer p. Disclosure All authors have declared no conflicts of interest.

Relationship between BRCA1 mRNA expression in tumor cells from malignant effusions and chemosensitivity to cisplatin in patients with metastatic malignant effusions

To explore the mRNA expression of breast cancer susceptibility gene 1 (BRCA1) in tumor cells isolated from malignant pleural and peritoneal effusions, and the predictive role of BRCA1 related to the efficacy of cisplatin-based chemotherapy. Tumor cells were isolated from malignant pleural and peritoneal effusions of 31 cancer patients. The response of these tumor cells to cisplatin was determined by CCK8 assay. Real time quantitative RT-PCR was used to examine the BRCA1 mRNA level in the primary culture cancer cells. The expression level of BRCA1 mRNA was 0.618 (0.014 - 18.063) in primary culture tumor cells. The IC(50) of DDP was 2.809 µg/ml in the primary culture tumor cells (0.118 - 19.439 µg/ml). Both BRCA1 mRNA expression and the tumor cells IC(50) of DDP were not significantly related with patient age, gender, the type of primary tumor, whether to accept the chemotherapy and effusion type (P > 0.05). The level of BRCA1 mRNA was negatively correlated with the chemosensitivity in terms of IC(50) of cisplatin (P < 0.001). Assessment of expression level of BRCA1 mRNA may be useful in predicting the efficacy of cisplatin-based chemotherapy in patients with metastatic malignant effusions.

ERCC1 and BRCA1 mRNA expression levels in metastatic malignant effusions is associated with chemosensitivity to cisplatin and/or docetaxel.

BackgroundOne of the major challenges in currently chemotherapeutic theme is lacking effective biomarkers for drug response and sensitivity. Our current study focus on two promising biomarkers, ERCC1 (excision repair cross-complementing group 1) and BRCA1 (breast cancer susceptibility gene 1). To investigate their potential role in serving as biomarkers for drug sensitivity in cancer patients with metastases, we statistically measure the mRNA expression level of ERCC1 and BRCA1 in tumor cells isolated from malignant effusions and correlate them with cisplatin and/or docetaxel chemosensitivity.MethodsReal-time quantitative PCR is used to analysis related genes expression in forty-six malignant effusions prospectively collected from non-small cell lung cancer (NSCLC), gastric and gynecology cancer patients. Viable tumor cells obtained from malignant effusions are tested for their sensitivity to cisplatin and docetaxel using ATP-TCA assay.ResultsERCC1 expression level is negatively correlated with the sensitivity to cisplatin in NSCLC patients (P = 0.001). In NSCLC and gastric group, BRCA1 expression level is negatively correlated with the sensitivity to cisplatin (NSCLC: P = 0.014; gastric: P = 0.002) while positively correlated with sensitivity to docetaxel (NSCLC: P = 0.008; gastric: P = 0.032). A significant interaction is found between ERCC1 and BRCA1 mRNA expressions on sensitivity to cisplatin (P = 0.010, n = 45).ConclusionOur results demonstrate that ERCC1 and BRCA1 mRNA expression levels are correlated with in vitro chemosensitivity to cisplatin and/or docetaxel in malignant effusions of NSCLC and gastric cancer patients. And combination of ERCC1 and BRCA1 may have a better role on predicting the sensitivity to cisplatin than the single one is considered.

BRCA1 Gene Expression in Breast Cancer: A Correlative Study between Real-time RT-PCR and Immunohistochemistry

Breast cancer is a major cause of cancer-related mortality in women. There are major discrepancies concerning the usefulness of various antibodies in detecting breast cancer susceptibility gene 1 (BRCA1) protein and its subcellular localization. The aim of the present study was to determine the specificity and sensitivity of immunohistochemistry (IHC) as a screening method for demonstrating BRCA1 expression. BRCA1 gene expression in archival paraffin-embedded breast cancer tissues was studied simultaneously at the protein and mRNA levels, and the two findings were compared. Forty-eight archival paraffin-embedded breast cancer tissues were studied for BRCA1 gene expression at protein level by IHC using four different antibodies against different BRCA1 epitopes and at mRNA level using real-time RT-PCR. BRCA1 mRNA expression was reduced or absent in 79% of the samples, and this finding correlated significantly with loss of BRCA1 protein expression in 83% of breast cancer tissues using one BRCA1 antibody studied (AB-1, against N-terminus epitope). The specificity of this antibody was 91.3%, and its sensitivity was 66.6%. There was no significant correlation between BRCA1 mRNA and protein expression as demonstrated by the remaining three antibodies. Antibody 8F7 had the highest sensitivity of 100%, but its specificity was 30.4% if mRNA levels were considered as the reference standard.

Role of BRCA1 in heat shock response.

The heat shock response is an evolutionarily conserved response to heat and other stresses that promotes the maintenance of key metabolic functions and cell survival. We report that exposure of human prostate (DU-145) and breast (MCF-7) cancer cells to heat (42 degrees C) caused a rapid disappearance of the breast cancer susceptibility gene-1 (BRCA1) protein, starting at approximately 1 h after the onset of heating and slightly lagging behind the increase in heat shock protein 70 (HSP70) levels. The heat-induced loss of BRCA1 occurred at the protein level, since: (1) BRCA1 mRNA expression was unaffected; and (2) the BRCA1 protein loss was also observed in DU-145 cells that expressed exogenous wild-type BRCA1 (wtBRCA1). In addition to heat regulation of BRCA1 protein levels, we also found that BRCA1 could modulate the heat shock response. Thus, wtBRCA1 overexpressing DU-145 cell clones showed significantly decreased sensitivity to heat-induced cytotoxicity; and Brca1 mutant mouse embryo fibroblasts showed increased sensitivity to heat. The DU-145 wtBRCA1 clones also showed increased expression of the small heat shock protein HSP27; and reporter assays revealed that wtBRCA1 stimulated a two to four-fold increase in HSP27 promoter activity, consistent with its ability to upregulate HSP27 mRNA and protein levels. In studies using epitope-tagged truncated BRCA1 proteins, the ability to stimulate the HSP27 promoter and to mediate heat-induced degradation required the amino-terminus but not the carboxyl-terminus of BRCA1. Although the heat-induced loss of BRCA1 appeared to be due to protein degradation, various protein metabolic agents (or combinations) failed to block this event, including: MG132 (a 26S proteasomal inhibitor), N-acetyl-leucyl-leucyl-norleucinal (a calpain inhibitor), z-VAD-fmk (a pan-caspase inhibitor), and ammonium chloride and chloroquine (which stabilize lysosomes). These findings suggest that in addition to its other functions, BRCA1 may participate in mammalian heat shock response pathways.