BRCA1 Gene Research Articles

Enhanced cancer cell proliferation and aggressive phenotype counterbalance in breast cancer with high BRCA1 gene expression.

While comprehensive research exists on the mutation of the DNA repair gene BRCA1, limited information is available regarding the clinical significance of BRCA1 gene expression. Given that cancer cell proliferation is aggrevated by DNA repair, we hypothesized that high BRCA1 gene expression breast cancer (BC) might be linked with aggressive tumor biology and poor clinical outcomes. The cohorts: The Cancer Genome Atlas (TCGA, n = 1069), METABRIC (n = 1903), and SCAN-B (n = 3273) were utilzed to obtain data of 6245 BC patients. BC patients without BRCA1 mutation exhibited higher BRCA1 expression, which was associated with DNA repair functionality. However, no such correlation was observed with BRCA2 expression. The association of high BRCA1 expression with cancer cell proliferation was evidenced by significant enrichment of cell proliferation-related gene sets, higher histological grade, and proliferation score. Furthermore, increased levels of homologous recombination deficiency, intratumoral heterogeneity, and altered fractions were associated with high BRCA1 expression. Moreover, BC with high BRCA1 expression exhibited reduced infiltration of dendritic cells and CD8 T-cells, while showing increased infiltration of Th1 cells. Surprisingly, BRCA1 expression was not associated with the survival of BC irrespective of the subtypes. Conversely, BC with low BRCA1 expression enriched cancer aggravating pathway gene sets, such as Cancer Stem Cell-related signaling (NOTCH and HEDGEHOG), Angiogenesis, Epithelial-Mesenchymal Transition, Inflammatory Response, and TGF-beta signaling. Despite being linked to heightened proliferation of cancer cells and unassertive phenotype, BRCA1 expression did not show any association with survival in BC.

Tetrahedral DNA nanostructures, graphene and carbon nanodots-based electrochemiluminescent biosensor for BRCA1 gene mutation detection.

Tetrahedral DNA nanostructures, graphene and carbon nanodots-based electrochemiluminescent biosensor for BRCA1 gene mutation detection.

The signature of SARS-CoV-2-related genes predicts the immune therapeutic response and prognosis in breast cancer

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an exceptionally contagious single-stranded RNA virus with a strong positive contagion. The COVID-19 pandemic refers to the swift worldwide dissemination of SARS-CoV-2 infection, which began in late 2019. The COVID-19 epidemic has disrupted many cancer treatments. A few reports indicate that the prevalence of SARS-CoV-2 has disrupted the treatment of breast cancer patients (BCs). However, the role of SARS-CoV-2 in the occurrence and prognosis of BC has not been elucidated. Here, we applied bioinformatics to construct a prognostic signature of SARS-CoV-2-related genes (SCRGs). Specifically, weighted gene co-expression network analysis (WGCNA) was utilized to extract co-expressed genes of differentially expressed genes (DEGs) in breast cancer and SCRGs. Then, we utilized the least absolute shrinkage and selection operator (LASSO) algorithm and univariate regression analysis to screen out three hub genes (DCTPP1, CLIP4 and ANO6) and constructed a risk score model. We further analyzed tumor immune invasion, HLA-related genes, immune checkpoint inhibitors (ICIs), and sensitivity to anticancer drugs in different SARS-CoV-2 related risk subgroups. In addition, we have developed a nomination map to expand clinical applicability. The results of our study indicate that BCs with a high-risk score are linked to negative outcomes, lower immune scores, and reduced responsiveness to anticancer medications. This suggests that the SARS-CoV-2 related signature could be used to guide prognosis assessment and treatment decisions for BCs.

Clinical Outcomes of Poly(ADP–Ribose) Polymerase Inhibitors as Maintenance Therapy in Patients with Ovarian Cancer in the Southeastern Region of Korea

Purpose: In this study, we aimed to retrospectively investigate the real-world clinical efficacy and adverse events of poly(adenosine diphosphate [ADP]-ribose) polymerase (PARP) inhibitors in real-world clinical practice among patients with newly diagnosed epithelial ovarian cancer. Methods: We retrospectively reviewed the medical records from hospitals. Patients with epithelial ovarian cancer treated with olaparib or niraparib as frontline maintenance treatment between 1 January 2014 and 31 December 2022 were included. Progression-free survival (PFS) was analyzed using the Kaplan–Meier method, and adverse events associated with PARP inhibitor treatment were investigated. Results: Ninety-six patients treated with PARP inhibitors were identified. The median follow-up period was 21.8 months (95% confidence interval [CI] 19.4–24.0). Twenty (20.1%) patients experienced disease progression, and two patients died. The median PFS was 45.3 months (95% CI 39.4–NA). BRCA1 or BRCA2 gene mutations and primary cytoreductive surgery were associated with better PFS. Adverse events of any grade occurred in 74 (77.1%) patients. Nineteen (19.8%) patients experienced PARP inhibitor therapy interruptions, and 35 (36.5%) patients experienced dose reductions. Only three patients discontinued the drug due to adverse events. Conclusions: In a real-world setting, PARP inhibitors showed efficacy comparable to that reported in published randomized controlled trials and had acceptable safety profiles.

An interpretable deep learning model for detecting BRCA pathogenic variants of breast cancer from hematoxylin and eosin-stained pathological images.

Determining the status of breast cancer susceptibility genes (BRCA) is crucial for guiding breast cancer treatment. Nevertheless, the need for BRCA genetic testing among breast cancer patients remains unmet due to high costs and limited resources. This study aimed to develop a Bi-directional Self-Attention Multiple Instance Learning (BiAMIL) algorithm to detect BRCA status from hematoxylin and eosin (H&E) pathological images. A total of 319 histopathological slides from 254 breast cancer patients were included, comprising two dependent cohorts. Following image pre-processing, 633,484 tumor tiles from the training dataset were employed to train the self-developed deep-learning model. The performance of the network was evaluated in the internal and external test sets. BiAMIL achieved AUC values of 0.819 (95% CI [0.673-0.965]) in the internal test set, and 0.817 (95% CI [0.712-0.923]) in the external test set. To explore the relationship between BRCA status and interpretable morphological features in pathological images, we utilized Class Activation Mapping (CAM) technique and cluster analysis to investigate the connections between BRCA gene mutation status and tissue and cell features. Significantly, we observed that tumor-infiltrating lymphocytes and the morphological characteristics of tumor cells appeared to be potential features associated with BRCA status. An interpretable deep neural network model based on the attention mechanism was developed to predict the BRCA status in breast cancer. Keywords: Breast cancer, BRCA, deep learning, self-attention, interpretability.

Identification of SLC31A1 as a prognostic biomarker and a target for therapeutics in breast cancer

Copper-induced cell death is regulated through protein lipoylation, which is critical for gene expression and phenotypic regulation. Neverless, the role of Cuproptosis-related genes in breast cancer (BC) remains unknown. This study aimed to construct a prognostic signature based on the expression of Cuproptosis-related genes in order to guide the diagnosis and treatment for BC. Cuproptosis-related genes prognostic signature has ata of 1250 BC tissues and 583 normal breast tissues were obtained from The Cancer Genome Atlas (TCGA), Genotype Tissue Expression (GTEx), and GEO GSE65212. The prognostic signature was established and evaluated with nineteen Cuproptosis-related genes. A series of in silico analyses based on SLC31A1, included expression analysis, independent prognostic analysis, correlation analysis, immune-related analysis and survival analysis. Finally, a series of cell experiments (including quantitative real-time polymerase chain reaction and western blot), and mice experiments were applied to evaluate the impact of SLC31A1 on BC. Cuproptosis-related genes prognostic signature has good predictive promising for survival in BC patients. We discovered that SLC31A1SLC31A1 was overexpressed in BC and was its independent prognostic factor. High expression of the SLC31A1 was correlated with poor prognosis and immune infiltrating of BC. SLC31A1 expression is associated with immune, chemotherapeutic and targeted therapy outcomes in BC. The proliferation, migration, and invasiveness of Her2 + enriched BC cells were decreased by SLC31A1 knockdown, also resulting in a decrease in tumor volume in mouse model. SLC31A1 is a candidate biomarker or therapeutic target in precision oncology, with diagnostic and prognostic significance in BC.

Impact of MTHFD2 Expression in Bladder/Breast Cancer and Screening of Its Potential Inhibitor.

Genes of folate-mediated 1 carbon metabolism are found to be highly upregulated in tumor cells and promote cancer cell proliferation. The current study aimed to determine the expression of the MTHFD2 gene in bladder and breast cancers. Furthermore, the determination of potential ligand-based inhibitors against MTHFD2 was performed in comparison with those of chemotherapeutic drugs and natural plant-based compounds. Semiquantitative expression analysis along with structure-based virtual ligand library screening was done to find plausible inhibitors. MTHFD2 expression was significantly increased with tumor stage progression both in low- and high-grade bladder cancer and especially in triple-negative breast cancer. Virtual ligand-based library screening against the three-dimensional MTHFD2 protein structure led to the identification of plausible inhibitors like MCULE-8109969891-0 and MCULE-9715677418-0-1 that displayed lower binding free energy as compared to that of already documented LY345899. Similar scaffold commercial drugs leucal (LEU), epirubicin (EPI), and lometrexol also displayed strong binding to the active site of MTHFD2. EPI and LEU in combinatorial therapy were also tested in vitro on MDA-MB-231 cells. The high doses of LEU in combination with EPI showed a significant reduction in cell viability at 2 and 3 μM concentrations. The interaction of breast cancer serum with high expression of MTHFD2 also showed an increase in binding of epirubicin in the presence of leucovorin. The decrease in the absorbance spectra of epirubicin at 37 and 53 °C displayed the stability induced by LEU on the interaction of EPI with the MTHFD2 binding pocket. Leucovorin tends to stabilize the interaction as the binding affinity is high even at 53 °C. Thus, MTHFD2 might be used as a cancer biomarker since its expression level changes drastically with tumor progression. Further experimental studies are required to establish the potential mode of inhibition of the novel small ligands. Future in vivo trials may validate the effectiveness of the combinatorial therapy.

Strong association of single nucleotide polymorphisms in BRCA1, ATM, and CHEK2 with breast cancer susceptibility in a sub-population of Iranian women.

Breast cancer (BC) is the most prevalent malignancy in females worldwide. Mutations in the DNA repair pathway genes contribute to a significant increase in BC risk. The present study aimed to assess the frequency of polymorphisms in BRCA1, ATM, and CHEK2 genes and their association with BC susceptibility in the Kurdish population from the West of Iran. In the present case-control study, the distribution of single nucleotide polymorphisms (SNPs) in CHEK2 (rs17879961), ATM (rs28904921), and BRCA1 (rs80357906, rs1555576855, rs1555576858, and rs397509247) genes were investigated in 335 BC cases and 354 healthy-matched controls by Taqman allelic discrimination assay. The chi-square goodness-of-fit test was employed for the assessment of Hardy-Weinberg Equation. Relative risk and odds ratios were calculated based on the Koopman asymptotic score and the Baptista-Pike method, respectively. Also, the sensitivity and specificity of each polymorphism were assessed using the Wilson-Brown test and a P-value < 0.05 indicating significant differences between the two groups in all assessments. Data showed there was a strong association between rs397509247 (OR = 7.53, 95% CI 1.88-90.91, p = 0.004), rs1555576858 (OR = 10.53, 95% CI 0.01-0.51, p = 0.0005), and rs80357906 (OR = 6.33, 95% CI 0.05-0.043, p < 0.0001) in BRCA1 gene and rs17879961 (OR = 3.52, 95% CI 0.084-0.946, p = 0.02) in CHEK2 gene, with BC risk in the population of interest. Among these, rs28904921 in ATM gene demonstrated the strongest association (OR = 72.66, 95% CI 0.007-0.214, p < 0.0001). This suggests that these SNPs, particularly rs28904921, are significantly associated with an increased risk of BC in the studied population. Our results indicated that BRCA1, ATM, and CHEK2 polymorphisms have a high frequency in the Iranian breast cancer population, with some mutant allele frequencies being much higher than those reported in other populations. We have also provided a simple, multiplex, rapid, and accurate genotyping assay that is useful in clinical settings.

Molecular analysis of BRCA1 and BRCA2 genes in La Rioja (Spain): five new variants.

To study BRCA1/2 gene variants in La Rioja in the northcentral area of Spain. We performed a molecular analysis of BRCA1 and BRCA2 in 642 individuals from 427 different families from June 2008 to December 2019. We identified 71 families with pathogenic variants in these genes, 32 families with BRCA1 variants and 39 families with BRCA2 variants. The pathogenic variants c.959delG in BRCA1 and c.1363_1369delTCAGAGA, c.1397dupA, c.4234_4236delACTinsC and c.8387delC in BRCA2 have not been previously described. The c.81-2A > T variant in BRCA1, detected in two unrelated families, has not been reported previously in the Spanish population. Two large genomic deletions were found in the BRCA1 gene in exons (Ex) 23-24 and Ex1A-1B-2, and one deletion was found in the BRCA2 gene in Ex2. The pathogenic variant c.5123C > A in BRCA1 was detected in 8 unrelated families and was the most frequent pathogenic variant in our population. The c.6024dupG mutation in BRCA2 was detected in 6 unrelated families; the c.2808_2011delACAA mutation in BRCA2 was found in 5 different families; the c.211A > G mutation in BRCA1 was found in three different families; and the c.68_69delAG, c81-2A > T, c.4038_4039delAA, and c.5266dupC variants in BRCA1 and the c.2457delA, c.2701delC, c.5116_5119delAATA, c.6275delTT, c.7558C > T and c.7617 + 1G > A variants in BRCA2 were found in two different families. The spectrum of pathogenic variants in the BRCA1/2 genes in La Rioja is similar to that in other Spanish regions, with some unique characteristics. The pathogenic c.6024dupG variant in the BRCA2 gene was detected in a large number of families and could have a founding effect in the Ebro riverside areas in the regions of La Rioja and Navarra. Not applicable.

Senescence-related genes as prognostic indicators in breast cancer survival.

Breast cancer is a leading cause of cancer-related mortality among women worldwide, particularly affecting those in their later years. As the incidence of breast cancer increases with age, understanding the biological mechanisms that link aging and cancer becomes crucial. Cellular senescence, a hallmark of aging, plays a dual role in cancer by inhibiting tumorigenesis while also contributing to tumor progression through the senescence-associated secretory phenotype (SASP). This study aims to investigate the prognostic significance of senescence-related genes in breast cancer. We utilized the SenMayo gene list, a comprehensive set of senescence-related genes, to analyze gene expression data from a large cohort of breast cancer samples. The data was sourced from the Kaplan-Meier plotter, an integrated database that compiles gene expression information from multiple independent cohorts. Cox proportional hazards regression and false discovery rate (FDR) corrections were employed to evaluate the correlation between gene expression and survival outcomes, aiming to establish a prognostic signature. Our findings demonstrate that higher expression levels of senescence-related genes are significantly associated with improved survival, while lower expression levels correlate with shorter survival outcomes. These results suggest that senescence-related pathways play a protective role in breast cancer, potentially serving as valuable prognostic indicators. The identification of a prognostic signature based on senescence-related genes underscores the importance of cellular senescence in breast cancer progression and survival. Our study highlights the potential of senescence-related biomarkers in enhancing patient stratification and informing treatment strategies, contributing to the growing body of literature on the intersection of aging and cancer.

UL16‑binding protein 1 is a significant prognostic and diagnostic marker for breast cancer.

The aim of the present study was to investigate the association between UL16 binding protein 1 (ULBP1) and the prognosis of patients with and immune cell infiltration in breast cancer (BRCA). The mRNA data of BRCA and immune-related genes were extracted from The Cancer Genome Atlas and were analyzed using bioinformatics tools. Subsequently, the results obtained by bioinformatics were validated through the collection of clinical patient data at the Zibo Central hospital (Zibo, China). The difference in the expression of the ULBP1 gene between BRCA tissues and normal precancerous tissues was analyzed, followed by validation using immunohistochemistry. By combining clinical data from patients with BRCA, the prognostic and diagnostic significance of the ULBP1 gene in patients with BRCA was analyzed. Gene enrichment analysis was conducted to gain insight into the molecular mechanisms underlying the regulatory role of ULBP1 in BRCA by analyzing its related functions and signaling pathways. Furthermore, single sample gene set enrichment analysis (ssGSEA) and Spearman's correlation analysis were performed to explore the correlation between ULBP1 as a target gene related with tumor immune cell infiltration. The data revealed that ULBP1 is a target gene associated with immunity and the prognosis of patients with BRCA. Patients with BRCA with a high expression of ULBP1 had a poorer prognosis. ULBP1 expression correlated with progesterone receptor expression, estrogen receptor expression and histological type in patients with BRCA; thus, it may serve as an independent predictor for the overall survival rate of patients. Functional enrichment analysis revealed a significant co-expression between ULBP1 and ULBP2, ULBP3, retinoic acid early transcript 1K, as well as a significant enrichment of pathways associated with carcinogenesis and immune suppression. ssGSEA and Spearman's correlation analysis demonstrated significant correlations between ULBP1 expression and tumor immune cells, as well as immune checkpoints. Overall, the present study demonstrated that ULBP1 was associated with BRCA immunity and might serve as a prognostic and diagnostic biomarker for patients with BRCA. In addition, it might also be a potential target for the immunotherapy of BRCA.

Positioning loss of PARP1 activity as the central toxic event in BRCA-deficient cancer

The mechanisms by which poly(ADP-ribose) polymerase 1 (PARP1) inhibitors (PARPi)s inflict replication stress and/or DNA damage are potentially numerous. PARPi toxicity could derive from loss of its catalytic activity and/or its physical trapping of PARP1 onto DNA that perturbs not only PARP1 function in DNA repair and DNA replication, but also obstructs compensating pathways. The combined disruption of PARP1 with either of the hereditary breast and ovarian cancer genes, BRCA1 or BRCA2 (BRCA), results in synthetic lethality. This has driven the development of PARP inhibitors as therapies for BRCA-mutant cancers. In this review, we focus on recent findings that highlight loss of PARP1 catalytic activity, rather than PARPi-induced allosteric trapping, as central to PARPi efficacy in BRCA deficient cells. However, we also review findings that PARP-trapping is an effective strategy in other genetic deficiencies. Together, we conclude that the mechanism-of-action of PARP inhibitors is not unilateral; with loss of activity or enhanced trapping differentially killing depending on the genetic context. Therefore, effectively targeting cancer cells requires an intricate understanding of their key underlying vulnerabilities.

Phenotypic evaluation of deep learning models for classifying germline variant pathogenicity.

Deep learning models for predicting variant pathogenicity have not been thoroughly evaluated on real-world clinical phenotypes. Here, we apply state-of-the-art pathogenicity prediction models to hereditary breast cancer gene variants in UK Biobank participants. Model predictions for missense variants in BRCA1, BRCA2 and PALB2, but not ATM and CHEK2, were associated with breast cancer risk. However, deep learning models had limited clinical utility when specifically applied to variants of uncertain significance.

Comprehensive analysis of the expression level, prognostic value, and immune infiltration of cuproptosis-related genes in human breast cancer.

As a novel cell death form, cuproptosis results from copper combining with lipidated proteins in the tricarboxylic acid cycle. To the best of our knowledge no study has yet comprehensively analyzed the relationship between cuproptosis-related genes and breast cancer. The expression, prognostic value, mutations, chemosensitivity, and immune infiltration of cuproptosis-related genes in breast carcinoma patients were analyzed, PPI networks were constructed, and enrichment analyses were performed based on these genes. TIMER, UALCAN, Kaplan-Meier plotter, Human Protein Atlas, cBioPortal, STRING, GeneMANIA, DAVID, and R program v4.0.3 were used to accomplish the analyses above. Compared to normal breast tissues, FDX1, LIAS, LIPT1, DLD, DLAT, PDHA1, MTF1, and GLS were down-regulated in breast cancer tissues, while CDKN2A was up-regulated. High expression of FDX1, LIAS, DLD, DLAT, MTF1, GLS, and CDKN2A were associated with favorable overall survival. Cuproptosis-related genes showed a high alteration rate (51.3%) in breast cancer, contributing to worse clinical outcomes. The expression levels of FDX1, LIPT1, DLD, DLAT, PDHA1, PDHB, MTF1, GLS, and CDKN2A were associated positively with 1 or more immune cell infiltrations in breast cancer. Patients with high levels of B cell, CD4+ T cell, CD8+ T cell, and dendritic cell infiltration had a higher survival rate at 10 years. This study comprehensively investigated relationships between cuproptosis and breast cancer by bioinformatic analyses. We found that cuproptosis-related genes were generally lowly expressed in breast carcinoma tissue. As the critical gene of cuproptosis, high expression of FDX1 was related to favorable prognoses in breast cancer patients; thus, it might be a potential prognostic marker. Moreover, genes associated with cuproptosis were linked to immune infiltration in breast cancer and this relationship affected the prognosis of breast cancer.

PARP Pioneers: Using BRCA1/2 Mutation-targeted Inhibition to Revolutionize Breast Cancer Treatment.

Breast Cancer stands on the second position in the world in being common and women happen to have it with high rate of about five-folds around the world. The causes of occurrence can matter with different humans be it external factors or the internal genetic ones. Breast cancer is primarily driven by mutations in the BRCA1 and BRCA2 susceptibility genes. These BC susceptibility genes encode proteins critical for DNA homologous recombination repair (HRR). Poly (ADP ribose) polymerases (PARP) are the essential enzymes involved in the repairing of the damaged DNA. So the inhibition of these inhibitors can be considered as the promising strategy for targeting cancers with defective damage in the deoxyribonucleic acid. Olaparib and talazoparib are PARP inhibitors (PARPi) are being employed for the monotherapies in case of the deleterious germline HER2-negative and BRCA-mutated breast cancer. The potency of PARP for trapping on DNA and causes cytotoxicity may have difference in the safety and efficacy with the PARPi. The PARPi have been found its place in the all different types of Breast Cancers and have shown potential benefits. The purpose of this review is to provide an update on the oral poly(ADP-ribose) polymerase (PARP)inhibitors for the improvement in the treatment and management of Breast Cancer.

Differential methylation of circulating free DNA assessed through cfMeDiP as a new tool for breast cancer diagnosis and detection of BRCA1/2 mutation

BackgroundRecent studies have highlighted the importance of the cell-free DNA (cfDNA) methylation profile in detecting breast cancer (BC) and its different subtypes. We investigated whether plasma cfDNA methylation, using cell-free Methylated DNA Immunoprecipitation and High-Throughput Sequencing (cfMeDIP-seq), may be informative in characterizing breast cancer in patients with BRCA1/2 germline mutations for early cancer detection and response to therapy.MethodsWe enrolled 23 BC patients with germline mutation of BRCA1 and BRCA2 genes, 19 healthy controls without BRCA1/2 mutation, and two healthy individuals who carried BRCA1/2 mutations. Blood samples were collected for all study subjects at the diagnosis, and plasma was isolated by centrifugation. Cell-free DNA was extracted from 1 mL of plasma, and cfMeDIP-seq was performed for each sample. Shallow whole genome sequencing was performed on the immuno-precipitated samples. Then, the differentially methylated 300-bp regions (DMRs) between 25 BRCA germline mutation carriers and 19 non-carriers were identified. DMRs were compared with tumor-specific regions from public datasets to perform an unbiased analysis. Finally, two statistical classifiers were trained based on the GLMnet and random forest model to evaluate if the identified DMRs could discriminate BRCA-positive from healthy samples.ResultsWe identified 7,095 hypermethylated and 212 hypomethylated regions in 25 BRCA germline mutation carriers compared to 19 controls. These regions discriminate tumors from healthy samples with high accuracy and sensitivity. We show that the circulating tumor DNA of BRCA1/2 mutant breast cancers is characterized by the hypomethylation of genes involved in DNA repair and cell cycle. We uncovered the TFs associated with these DRMs and identified that proteins of the Erythroblast Transformation Specific (ETS) family are particularly active in the hypermethylated regions. Finally, we assessed that these regions could discriminate between BRCA positives from healthy samples with an AUC of 0.95, a sensitivity of 88%, and a specificity of 94.74%.ConclusionsOur study emphasizes the importance of tumor cell-derived DNA methylation in BC, reporting a different methylation profile between patients carrying mutations in BRCA1, BRCA2, and wild-type controls. Our minimally invasive approach could allow early cancer diagnosis, assessment of minimal residual disease, and monitoring of response to therapy.

Arsenic and Chromium Induced Toxicity on Zebrafish Kidney: Mixture Effects on Oxidative Stress and Involvement of Nrf2-Keap1-ARE, DNA Repair, and Intrinsic Apoptotic Pathways.

In polluted water, cooccurrences of two carcinogens, arsenic (As) and chromium (Cr), are extensively reported. Individual effects of these heavy metals have been reported in kidney of fishes, but underlying molecular mechanisms are not well established. There is no report on combined exposure of As and Cr in kidney. Thus, the present study investigated and compared individual and combined effects of As and Cr on zebrafish (Danio rerio) kidney treating at their environmentally relevant concentrations for 15, 30, and 60 days. Increased ROS levels, lipid peroxidation, GSH level, and decreased catalase activity implied oxidative stress in treated zebrafish kidney. Damage in histoarchitecture in treated groups was also noticed. The current study involved gene expression study of Nrf2, an important transcription factor of cellular stress responses along with its negative regulator Keap1 and downstream antioxidant genes nqo1 and ho1. Results indicated activation of Nrf2-Keap1 pathway after combined exposure. Expression pattern of ogg1, apex1, polb, and creb1 revealed the inhibition of base excision repair pathway in treatments. mRNA expression of tumor suppressor genes p53 and brca2 was also altered. Expressional alteration in bax, bcl2, caspase9, and caspase 3 indicated apoptosis (intrinsic pathway) induction, which was maximum in combined group. Inhibition of DNA repair and induction of apoptosis indicated that the activated antioxidant system was not enough to overcome the damage caused by As and Cr. Overall, this study revealed additive effects of As and Cr in zebrafish kidney after chronic exposure focusing cellular antioxidant and DNA damage responses.

TGFβ1-TNFα regulated secretion of neutrophil chemokines is independent of epithelial-mesenchymal transitions in breast tumor cells.

Neutrophils have tumor-promoting roles in breast cancer and are detected in higher numbers in aggressive breast tumors. How aggressive breast tumors recruit neutrophils remains undefined. Here, we investigated the roles of TGF-β1 and TNF-α in the regulation of neutrophil recruitment by breast cancer cells. TGF-β1 and TNF-α are pro-inflammatory factors upregulated in breast tumors and induce epithelial to mesenchymal transitions (EMT), a process linked to cancer cell aggressiveness. We report that, as expected, dual treatment with TGF-β1 and TNF-α induces EMT signatures in premalignant M2 cells, which are part of the MCF10A breast cancer progression model. Conditioned media (CM) harvested from M2 cells treated with TGF-β1/TNF-α gives rise to amplified neutrophil chemotaxis compared to CM from control M2 cells. This response correlates with higher levels of the neutrophil chemokines CXCL1, CXCL2, and CXCL8 and is significantly attenuated in the presence of a CXCL8-neutralizing antibody. Furthermore, we found that secretion of CXCL1 and CXCL8 from treated M2 cells depends on p38MAPK activity. By combining gene editing, immunological and biochemical approaches, we show that the regulation of neutrophil recruitment and EMT signatures are not mechanistically linked in treated M2 cells. Finally, analysis of publicly available cancer cell line transcriptomic databases revealed a significant correlation between CXCL8 and TGF-β1/TNF-α-regulated or effector genes in breast cancer. Together, our findings establish a novel role for the TGF-β1/TNF-α/p38 MAPK signaling axis in regulating neutrophil recruitment in breast cancer, independent of TGF-β1/TNF-α regulated EMT.

Benign polymorphisms in the BRCA genes with linkage disequilibrium is associated with cancer characteristics.

Germline pathogenic mutation of the BRCA gene increases the prevalence of breast cancer. Reports on the benign variants of BRCA genes are limited. However, the definition of these variants might be altered with the accumulation of clinical evidence. Therefore, in the present study, we focused on benign single nucleotide polymorphisms (SNPs) of BRCA genes. Linkage disequilibrium was calculated from whole genome sequencing of the BRCA genes obtained from 500 healthy controls and 49 breast cancer patients. Sanger sequencing was used to confirm the mutation. The linkage disequilibrium was noted for seven and three SNPs in the BRCA1 and BRCA2 genes, respectively. Breast cancer with BRCA1/2 linkage disequilibrium was not correlated with a personal history of benign diseases or family history of cancer. Nevertheless, breast cancer with BRCA1 linkage disequilibrium was correlated with high tumor-infiltrating lymphocytes and positive extensive intraductal components. The patients with BRCA1 linkage disequilibrium tended to have worse disease-specific survival. Cancers with BRCA2 linkage disequilibrium are associated with a lower ratio of grade III cancer. Moreover, patients with BRCA2 linkage disequilibrium tended to have better overall survival. In conclusion, linkage disequilibrium from benign SNPs of the BRCA genes potentially affects cancer characteristics.

Molecular mechanisms of novel selective glucocorticoid receptor agonist action in breast cancer cells

Introduction. Glucocorticoids (GC) are widely used in breast cancer (BC) therapy to reduce the side effects of cytostatic drugs and may exhibit antiproliferative effects on luminal BC cells. The biological action of GC is mediated by glucocorticoid receptor (GR) by two mechanisms: transrepression, which determines the therapeutic effect of GC, and transactivation (associated with the development of side effects, resistance to cytotoxic drugs, cancer progression and metastasis). Selective GR agonists (SEGRA) which may selective activate transrepression are a promising alternative to GC to use in combination cancer therapy. One of the most studied SEGRA is Compound A (CpdA). The instability of CpdA limits its use in clinical practice. So recently we performed synthesis and evaluation of biological activities of the CpdA analogue, CpdA-03.Aim. To compare the effects of SEGRA CpdA-03 and CpdA and dexamethasone on proliferative activity of breast cancer cells, as well as receptor nuclear translocation and activation of GR-dependent genes in breast cancer cells.Materials and methods. Luminal (MCF-7) and triple negative (MDA-MB-231) BC cell lines were used. The effect of CpdA-03 on proliferation was evaluated by direct counting of viable cells with trypan blue staining. The effect of the compound on cell distribution by cell cycle phases was assessed by flow cytofluorimetry with propidium iodide staining. Changes in the expression of GR-dependent genes after incubation with CpdA-03 were evaluated by quantitative polymerase chain reaction. Additionally, the ability of the new SEGRA to induce transactivation-associated translocation of the receptor to the nucleus was evaluated by Western blotting.Results. CpdA-03 was shown to suppress proliferation of luminal and triple negative BC cells. This compound causes changes in the expression of a number of GC-inducible genes, but does not stimulate GR phosphorylation and translocation to the nucleus in BC cells.Conclusion. The observed suppression of cell proliferation, as well as the ability of CpdA-03 to reduce gene expression of proteins regulating intercellular adhesion and cell migration, intracellular signaling, stress response, and transcription in BC cells makes it relevant for further development of the drug for use in the combination therapy of cancers including breast cancer.