Characteristics Of Breast Cancer Cells Research Articles

Super-enhancer profiling reveals ThPOK/ZBTB7B, a CD4 + cell lineage commitment factor, as a master regulator that restricts breast cancer cells to a luminal non-migratory phenotype.

Despite efforts to understand breast cancer biology, metastatic disease remains a clinical challenge. Identifying suppressors of breast cancer progression and mechanisms of transition to more invasive phenotypes could provide game changing therapeutic opportunities. Transcriptional deregulation is central to all malignancies, highlighted by the extensive reprogramming of regulatory elements that underlie oncogenic programs. Among these, super-enhancers (SEs) stand out due to their enrichment in genes controlling cancer hallmarks. To reveal novel breast cancer dependencies, we integrated the analysis of the SE landscape with master regulator activity inference for a series of breast cancer cell lines. As a result, we identified T - h elper-inducing Poxviruses and Zinc-finger ( PO Z)/ K rüppel-like factor (ThPOK, ZBTB7B ), a CD4 + cell lineage commitment factor, as a breast cancer master regulator that is recurrently associated with a SE. ThPOK expression is highest in luminal breast cancer but is significantly reduced in the basal subtype. Manipulation of ThPOK levels in cell lines shows that its repressive function restricts breast cancer cells to an epithelial phenotype by suppressing the expression of genes involved in the epithelial-mesenchymal transition (EMT), WNT/β-catenin target genes, and the pro-metastatic TGFβ pathway. Our study reveals ThPOK as a master transcription factor that restricts the acquisition of metastatic features in breast cancer cells.

The mevalonate pathway contributes to breast primary tumorigenesis and lung metastasis.

The mevalonate pathway plays an important role in breast cancer and other tumor types. However, many issues remain obscure as yet regarding its mechanism of regulation and action. In the present study, we report that the expression of mevalonate pathway enzymes is mediated by theRHO guanosine nucleotide exchange factors VAV2 and VAV3 in a RAC1- and sterol regulatory element-binding factor (SREBF)-dependent manner in breast cancer cells. Furthermore, in vivo tumorigenesis experiments indicated that the two most upstream steps of this metabolic pathway [3-hydroxy-3-methylglutaryl-coenzyme A synthase 1 (HMGCS1) and 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR)] are important for primary tumorigenesis, angiogenesis, and cell survival in breast cancer cells. HMGCR, but not HMGCS1, is also important for the extravasation and subsequent fitness of breast cancer cells in the lung parenchyma. Genome-wide expression analyses revealed that HMGCR influences the expression of gene signatures linked to proliferation, metabolism, and immune responses. The HMGCR-regulated gene signature predicts long-term tumor recurrence but not metastasis in cohorts of nonsegregated and chemotherapy-resistant breast cancer patients. These results reveal a hitherto unknown, VAV-catalysis-dependent mechanism involved in the regulation of the mevalonate pathway in breast cancer cells. They also identify specific mevalonate-pathway-dependent processes that contribute to the malignant features of breast cancer cells.

Deciphering the TCF19/miR-199a-5p/SP1/LOXL2 pathway: Implications for breast cancer metastasis and epithelial-mesenchymal transition

Globally, breast cancer (BC) is the predominant malignancy with a significant death rate due to metastasis. The epithelial-mesenchymal transition (EMT) is a fundamental initiator for metastatic progression. Through advanced computational strategies, TCF19 was identified as a critical EMT-associated gene with diagnostic and prognostic significance in BC, based on a novel EMT score. Molecular details and the pro-EMT impact of the TCF19/miR-199a-5p/SP1/LOXL2 axis were explored in BC cell lines through in vitro validations, and the oncogenic and metastatic potential of TCF19 and LOXL2 were investigated using subcutaneous and tail-vein models. Additionally, BC-specific enrichment of TCF19 and LOXL2 was measured using a distribution landscape driven by diverse genomic analysis techniques. Molecular pathways revealed that TCF19-induced LOXL2 amplification facilitated migratory, invasive, and EMT activities of BC cells in vitro, and promoted the growth and metastatic establishment of xenografts in vivo. TCF19 decreases the expression of miR-199a-5p and alters the nuclear dynamics of SP1, modulating SP1’s affinity for the LOXL2 promoter, leading to increased LOXL2 expression and more malignant characteristics in BC cells. These findings unveil a novel EMT-inducing pathway, the TCF19/miR-199a-5P/SP1/LOXL2 axis, highlighting the pivotal role of TCF19 and suggesting potential for novel therapeutic approaches for more focused BC interventions.

SMARCC2 silencing suppresses oncogenic activation through modulation of chromatin accessibility in breast cancer

SWI/SNF chromatin remodeling complexes play a key role in gene transcription as epigenetic regulators and are typically considered to act as tumor suppressors in cancers. Compared to other cancer-related components of the SWI/SNF complex, research on SMARCC2, a component of the initial BAF core, has been relatively limited. This study aimed to elucidate the role of SMARCC2 in breast cancer by employing various in vitro and in vivo methods including cell proliferation assays, mammosphere formation, and xenograft models, complemented by RNA-seq, ATAC-seq, and ChIP analyses. The results showed that SMARCC2 silencing surprisingly led to the suppression of breast tumorigenesis, indicating a pro-tumorigenic function for SMARCC2 in breast cancer, which contrasts with the roles of other SWI/SNF subunits. In addition, SMARCC2 depletion reduces cancer stem cell features of breast cancer cells. Mechanistic study showed that SMARCC2 silencing downregulated the oncogenic Ras-PI3K signaling pathway, likely by directly regulating the chromatin accessibility of the enhancers of the key genes such as PIK3CB. Together, these results expand our understanding of the SWI/SNF complex's role in cancer development and identify SMARCC2 as a promising new target for breast cancer therapies.

Abstract PO3-25-12: Tigecycline-Induced Metabolic Reprogramming and Cytokine Modulation Suppress the Characteristics of Breast Cancer Cells

Abstract Objective: Patients with advanced breast cancer are prone to recurrence and metastasis. Hence, there is still a need to find new potential drugs or adjuvants to improve prognosis. The Warburg effect, which is highly dependent on glycolysis, has been found to be present in the energy metabolism of tumors, including breast cancer. The effect also promotes the production of cytokines, to adapt the inflammatory microenvironment of tumor. However, drugs targeting Warburg effect and inflammatory environment are rarely reported in the treatment of breast cancer. Tigecycline (Tige) is a commonly used glycylcycline antibiotic. Previous research has indicated it impede mitochondrial oxidative phosphorylation (OXPHOS) in various solid tumors. Based on the team's previous research, our study aimed to investigate whether Tige could inhibit breast cancer development by interfering with the Warburg effect and the inflammatory environment. Methods: MB231, MB468 and MCF7, T47D, which represent triple-negative and estrogen receptor positive breast cancers, were treated with Tige at different concentrations for different periods of time. CCK8, colony formation and sphere formation assays were used to evaluate the effects on proliferation and tumor stemness in vitro, respectively. The effects on migration and invasion were evaluated by wound healing assay and Transwell. RNA sequencing was used to explore the genes altered and analyze the pathways involved. After labeling with probes, the changes of reactive oxygen species (ROS) were detected by fluorescence microscope, microplate reader, and flow cytometry. Cell cycle and apoptosis were detected by flow cytometry. Liquid cytokine chip was used to analyze the secretion of cytokines. Electron microscopy was performed to observe the changes in mitochondrial morphology. RT-PCR was used to detect the expression of rate-limiting enzymes in glycolysis pathway. Glucose consumption, lactate and pyruvate production were measured using glucose, lactate and pyruvate detection kits, respectively. Western blot was used to detect the changes of respiratory chain protein complex and other related pathway proteins in OXPHOS. Results: Four breast cancer cells showed a significant decrease in cell proliferation, invasion and migratory ability after Tige treatment. Sphere-forming assays also showed that Tige had an effect on the stemness of breast cancer. RNA-sequencing showed that glycolysis, cell cycle, and immune-related pathways were inhibited after Tige treatment, and ROS production analysis revealed a decrease in ROS production. Flow cytometry also revealed that the cell cycle was arrested in S phase without significant apoptosis. Cytokine liquid chip analysis showed that the secretion of many cytokines, mainly interleukin (such as IL-1B), was inhibited after Tige intervention. RT-PCR results showed that the expression of several rate-limiting enzymes of the glycolytic pathway decreased. Glucose, lactate and pyruvate assay results showed that Tige reduced glucose uptake and lactate, pyruvate production. Electron microscopy results revealed that mitochondria in Tige treated cells showed significant contractures. WB results also showed a decrease in the expression of OXPHOS-related proteins. However, due to the heterogeneity of the four breast cancer cells, the degree of change in these capacities was not entirely consistent. Conclusions: Tige not only inhibits mitochondrial OXPHOS, but also inhibits the glycolysis pathway, which results in the inhibition of glucose uptake and the production of pyruvate and lactate. The secretion of early pro-inflammatory cytokines also affected. Therefore, this study suggests that Tige may change the glucose metabolism and energy metabolism, and also change the inflammatory environment of breast tumors, which provides new evidence for the anti-tumor effect of Tige in breast cancer. Citation Format: Haochen Yu, Lingfeng Tang, Shengchun Liu. Tigecycline-Induced Metabolic Reprogramming and Cytokine Modulation Suppress the Characteristics of Breast Cancer Cells [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO3-25-12.

LINC00460-FUS-MYC feedback loop drives breast cancer metastasis and doxorubicin resistance.

Therapeutic resistance and metastasis largely contribute to mortality from breast cancer and therefore understanding the underlying mechanisms of such remains an urgent challenge. By cross-analysis of TCGA and GEO databases, LINC00460 was identified as an oncogenic long non-coding RNA, highly expressed in Doxorubicin resistant breast cancer. LINC00460 was further demonstrated to promote stem cell-like and epithelial-mesenchymal transition (EMT) characteristics in breast cancer cells. LINC00460 interacts with FUS protein with consequent enhanced stabilization, which further promotes MYC mRNA maturation. LINC00460 expression was transcriptionally enhanced by c-MYC protein, forming a positive feedback loop to promote metastasis and Doxorubicin resistance. LINC00460 depletion in Doxorubicin-resistant breast cancer cells restored sensitivity to Doxorubicin and increased the efficacy of c-MYC inhibitor therapy. Collectively, these findings implicate LINC00460 as a promising prognostic biomarker and potential therapeutic target to overcome Doxorubicin resistance in breast cancer.

Teadenol B as a Component of Microorganism-Fermented Tea Extract Inhibited Breast Cancers by Promoting Autophagy.

Breast cancer is a significant threat to life and health, which needs more safe and effective drugs to be explored. Teadenol B is a characteristic chemical component of microbial fermented tea. This study discovered that teadenol B could exhibit obvious inhibitory effects on all four different clinical subtype characteristics of breast cancer cells. Proteomic studies show that deoxycytidine triphosphate deaminase (DCTD), which could block DNA synthesis and repair DNA damage, had the most significant and consistent reduction in all four types of breast cancer cells with the treatment of teadenol B. Considering MDA-MB-231 cells exhibit poor clinical prognosis and displayed substantial statistical differences in KEGG pathway enrichment analysis results, we investigated its impact on the size and growth of MDA-MB-231 triple-negative breast tumors transplanted into nude mice and demonstrated that teadenol B significantly suppressed tumor growth without affecting body weight significantly. Finally, we found that the conversion of LC3-I to LC3-II in MDA-MB-231 increased significantly with teadenol B treatment. This proved that teadenol B could be a strong autophagy promotor, which explained the down-regulation of DCTD to some extent and may be the potential mechanism underlying teadenol B's anti-breast cancer effects. This finding provides new evidence for drinking fermented tea to prevent breast cancer and highlights the potential of teadenol B as a novel therapeutic option for breast cancer prevention and treatment, necessitating further investigations to clarify its exact target and the details involved.

The Soft Nanodots as Fluorescent Probes for Cell Imaging: Analysis of Cell and Spheroid Penetration Behavior of Single Chain Polymer Dots.

This study describes the formation, size control, and penetration behavior of polymer nanodots (Pdots) consisting of single or few chain polythiophene-based conjugated polyelectrolytes (CPEs) via nanophase separation between good solvent and poor solvent of CPE. Though the chain singularity may be associated with dilution nanophase separation suggests that molecules of a good solvent create a thermodynamically driven solvation layer surrounding the CPEs and thereby separating the single chains even in their poor solvents. This statement is therefore corroborated with emission intensity/lifetime, particle size, and scattering intensity of polyelectrolyte in good and poor solvents. Regarding the augmented features, Pdots are implemented into cell imaging studies to understand the nuclear penetration and to differentiate the invasive characteristics of breast cancer cells. The python based red, green, blue (RGB) color analysis depicts that Pdots have more nuclear penetration ability in triple negative breast cancer cells due to the different nuclear morphology in shape and composition and Pdots have penetrated cell membrane as well as extracellular matrix in spheroid models. The current Pdot protocol and its utilization in cancer cell imaging are holding great promise for gene/drug delivery to target cancer cells by explicitly achieving the very first priority of nuclear intake.

Single-cell analysis of matrisome-related genes in breast invasive carcinoma: new avenues for molecular subtyping and risk estimation.

The incidence of breast cancer remains high and severely affects human health. However, given the heterogeneity of tumor cells, identifying additional characteristics of breast cancer cells is essential for accurate treatment. This study aimed to analyze the relevant characteristics of matrix genes in breast cancer through the multigroup data of a breast cancer multi-database. The related characteristics of matrix genes in breast cancer were analyzed using multigroup data from the breast cancer multi database in the Cancer Genome Atlas, and the differential genes of breast cancer matrix genes were identified using the elastic net penalty logic regression method. The risk characteristics of matrix genes in breast cancer were determined, and matrix gene expression in different breast cancer cells was evaluated using real-time fluorescent quantitative polymerase chain reaction (PCR). A consensus clustering algorithm was used to identify the biological characteristics of the population based on the matrix molecular subtypes in breast cancer, followed by gene mutation, immune correlation, pathway, and ligand-receptor analyses. This study reveals the genetic characteristics of cell matrix related to breast cancer. It is found that 18.1% of stromal genes are related to the prognosis of breast cancer, and these genes are mostly concentrated in the biological processes related to metabolism and cytokines in protein. Five different matrix-related molecular subtypes were identified by using the algorithm, and it was found that the five molecular subtypes were obviously different in prognosis, immune infiltration, gene mutation and drug-making gene analysis. This study involved analyzing the characteristics of cell-matrix genes in breast cancer, guiding the precise prevention and treatment of the disease.

CD24hiCD27+ Bregs within Metastatic Lymph Nodes Promote Multidrug Resistance in Breast Cancer.

Axillary lymph nodes (LN) are the primary and dominant metastatic sites in breast cancer. However, the interaction between tumor cells and immune cells within metastatic LNs (mLN) remains poorly understood. In our study, we explored the effect of CD24hiCD27+ regulatory B cells (Breg) within mLNs on orchestrating drug resistance of breast cancer cells. We collected mLN samples from patients with breast cancer who had received standard neoadjuvant therapy (NAT) and analyzed the spatial features of CD24hiCD27+ Bregs through multicolor immunofluorescence staining. The effect of CD24hiCD27+ Bregs on drug resistance of breast cancer cells was evaluated via in vitro experiments. A mouse model with mLNs was used to evaluate the strategies with blocking the interactions between Bregs and breast cancer for improving tumor regression within mLNs. In patients with breast cancer who had received NAT, there is a close spatial correlation between activated CD24hiCD27+ Bregs and residual tumor cells within mLNs. Mechanistically, CD24hiCD27+ Bregs greatly enhance the acquisition of multidrug resistance and stem-like features of breast cancer cells by secreting IL6 and TNFα. More importantly, breast cancer cells further promote the activation of CD24hiCD27+ Bregs via CD40L-dependent and PD-L1-dependent proximal signals, forming a positive feedback pattern. PD-L1 blockade significantly attenuates the drug resistance of breast cancer cells induced by CD24hiCD27+ Bregs, and addition of anti-PD-L1 antibody to chemotherapy improves tumor cell remission in mLNs. Our study reveals the pivotal role of CD24hiCD27+ Bregs in promoting drug resistance by interacting with breast cancer cells in mLNs, providing novel evidence for an improved strategy of chemoimmunotherapy combination for patients with breast cancer with mLNs.

Tetracaine downregulates matrix metalloproteinase activity and inhibits invasiveness of strongly metastatic MDA-MB-231 human breast cancer cells

Tetracaine, a long-acting amino ester-type local anesthetic, prevents the initiation and propagation of action potentials by reversibly blocking voltage-gated sodium channels (VGSCs). These channels, which are highly expressed in several carcinomas (e.g. breast, prostate, colon and lung cancers) have been implicated in promoting metastatic behaviours. Recent evidence suggests that local anesthetics can suppress cancer progression. In this paper, we aimed to explore whether tetracaine would reduce the invasive characteristics of breast cancer cells. In a comparative approach, we used two cell lines of contracting metastatic potential: MDA-MB-231 (strongly metastatic) and MCF-7 (weakly metastatic). Tetracaine (50 μM and 75 μM) did not affect the proliferation of both MDA-MB-231 and MCF-7 cells. Importantly, tetracaine suppressed the migratory, invasive, and adhesive capacities of MDA-MB-231 cells; there was no effect on the motility of MCF-7 cells. Tetracaine treatment also significantly decreased the expression and activity levels of MMP-2 and MMP-9, whilst increasing TIMP-2 expression in MDA-MB-231 cells. On the other hand, VGSC α/Nav1.5 and VGSC-β1 mRNA and protein expression levels were not affected. We conclude that tetracaine has anti-invasive effects on breast cancer cells and may be exploited clinically, for example, in surgery and/or in combination therapies.

LGR5 As a Potential Therapeutic Target for Breast Cancer: A Systematic Review and Meta-analysis.

Breast cancer is the world's most common malignancy. Despite significant advances in the diagnosis and treatment of the disease, the associated mortality rate is still high. Tumor initiating cells known as cancer stem cells with unique abilities are suspected responsible for therapy failure and poor prognosis. Leucine-rich repeat-containing G-protein-coupled receptor 5 (LGR5) is a cancer stem cell marker that promotes aggressive features in breast cancer cells. So, the aim of this study was to perform a systematic review and meta-analysis to evaluate LGR5 as a therapeutic target for breast cancer. This systematic review and meta-analysis were performed using databases of Web of Science, Scopus, and PubMed. We searched these databases with LGR5 and Breast Cancer and related keywords based on the mesh database until Oct12, 2021. All studies that reported the rate of LGR5 high expression with Immunohistochemistry in breast cancer patients were included in this review. We used the STATA and random effect models for data analysis. Finally, 7 studies including 2632 breast cancer samples were studied. The pooled prevalence of LGR5 high expression in breast cancer was 48.6 % (CI95%: 40.5-56.7%, I2=0.0) and in triple negative was 48.6% (CI95%: 38.4-58.7%, I2= 0.0). Our findings show that the rate of LGR5 high expression in breast cancer in general and especially in triple-negative was considerable and it seems that this is a potential therapeutic target for breast cancer.

Cellular morphology-mediated functional characteristics of breast cancer cells

Cellular morphology-mediated functional characteristics of breast cancer cells

Design and development of a new metamaterial sensor-based Minkowski fractal antenna for medical imaging

The metamaterial sensor antenna is numerically designed to detect breast cancer using breast cancer cell lines, especially relying on the electrical characteristics of breast cancer cells, and designed antenna is measured and the results are observed. The metamaterial sensor antenna is a simple and efficient antenna which is designed using the Minkowski fractal curve with a ring-shaped Split Ring Resonator (SRR). The SRR is chosen because of its inductive and capacitive resonating properties. In addition, the Minkowski fractal curve is used as a defective ground structure to improve sensor sensitivity and selectivity. The numerical investigations are based on different iterations of the Minkowski fractal curve. In that iteration, the third iteration of the Minkowski fractal gives better results. The designed antenna is tested with breast cancer cell lines, and it resonates at a frequency of 2.35, 2.42, and 2.52 GHz for different dielectric constants and conductivity. The simulated design antenna is tested with different cancer cell lines like MDA-MB-231, MCF-7, and HS758-T to ensure its performance and selectivity. The measured result of the fabricated antenna shows that the antenna design resonates at the same frequency as the simulated antenna results.

IGHG1 promotes malignant progression in breast cancer cells through the regulation of AKT and VEGF signaling.

Immunoglobulin heavy constant chain gamma 1 (IGHG1) is highly expressed in a variety of cancers and is considered an emerging prognostic marker. Overexpression of IGHG1 in breast cancer tissues has also been demonstrated, but an in-depth analysis of its role in disease progression has not been explored. In this study, we used a range of molecular and cell-based assays to show that increased expression of IGHG1 in breast cancer cells activates AKT and vascular endothelial growth factor (VEGF) signaling, leading to enhanced cell proliferation, invasion, and angiogenesis. We further showed that IGHG1-silencing can suppress the neoplastic characteristics of breast cancer cells in vitro and suppresses tumor growth in nude mice. These data reveal a key role of IGHG1 in the malignant progression of breast cancer cells and highlight its potential as a prognostic marker and therapeutic target to control metastasis and angiogenesis in malignant breast tissue.

MiR 216b modulates cisplatin resistance and stem cell like features in breast cancer cells by targeting E2F4

Purpose: To study the influence of miR-216b expression in breast cancer (BC), and the underlying mechanism(s) of action. Methods: Viability of BC cell lines was determined using CCK-8 as well as colony formation assays, while the abundance of mRNAs of key genes was assessed by quantitative reverse transcription polymerase chain reaction (qRT-PCR). Western blot assay was utilized to measure protein expressions of E2F4 and stem cell markers. Bioinformatics and dual-luciferase procedures were deployed to predict the targets of miR-216b on 3′-UTR of E2F4.
 Results: MiR-216b was reduced in BC tissues and mammary carcinoma cell line, MCF-7, relative to those in paracancerous tissue and normal breast cell line, MCF-10A (p < 0.05). Compared with miR-NC group, cell viability, median inhibitory concentration (IC50), and potential to form colonies in cisplatin-insensitive cell line MCF-7/DDP were reduced by miR-216b. Moreover, MiR-216b suppressed stem cell characteristics and decreased the expressions of ALDH1 and Oct-4 in BC cells. Inhibition of miR-216b resulted in significant increase in microsphere formation and expressions of ALDH1 and Oct-4, when compared with NC-inhibitor group. In addition, E2F transcription factor 4 (E2F4) was identified as the downstream gene of miR-216b. Knockdown of E2F4 annulled the influence of miR-216b on insensitivity to cisplatin and stem cell likeness of MCF-7/DDP.
 Conclusion: MiR-216b induces increase in BC response to cisplatin and suppressed stem cell characteristics by regulating E2F4. This finding may be useful for developing strategies aimed at reversing cisplatin insensitivity in BC.

Cellular morphology and functional characteristics of breast cancer cells

When traction forces are generated in the cells underlying extracellular matrix (ECM) including artificial scaffolds, the cells feel essentially stiffness of the surrounding microenvironment and respond to applied forces and exert forces in the matrix, in which the traction forces can change cellular morphology and cytoskeletal structure. To date, analysis of cell morphology, including quantitative measurements such as cytoplasm roundness, cytoplasm elongation factor, nuclear elongation factor, ratio nuclear area to cytoplasm area ratio (AN/AC), nuclear dimension, and nuclear height, has been widely used in cancer diagnostics and hematology. Increasing evidence suggests that the extracted morphological features such as cell area and the length of major and minor axes, could also be used to analyze the dynamic changes of cells in diseases of the nervous system and cellular stress related phenomena. Furthermore, multivariate analyses of morphological data suggest that quantitative cytology may be a useful adjunct to conventional tests for the selection of new substances. Thus, understanding the interaction between microenvironment and cancer cells via cellular morphology is critical subject to tackle metastatic spread of cancer cells and its many associated issues. In this topic, the cellular morphological parameters and functional characteristics of cancer cells are summarized.

Ring finger protein 126 promotes breast cancer metastasis and serves as a potential target to improve the therapeutic sensitivity of ATR inhibitors

Background/aimsThis study explores the relationship between the E3 ubiquitin ligase Ring finger protein 126 (RNF126) and early breast cancer metastasis and tests the hypothesis that RNF126 determines the efficacy of inhibitors targeting Ataxia telangiectasia mutated and Rad3-related kinase (ATR).MethodsVarious metastasis-related genes were identified by univariable Cox proportional hazards regression analysis based on the GSE11121 dataset. The RNF126-related network modules were identified by WGCNA, whereas cell viability, invasion, and migration assays were performed to evaluate the biological characteristics of breast cancer cells with or without RNF126 knockdown. MTT, immunoblotting, immunofluorescence, and DNA fiber assays were conducted to determine the efficiency of ATR inhibitor in cells with or without RNF126 knockdown.ResultsRNF126 was associated with early breast cancer metastasis. RNF126 promoted breast cancer cell proliferation, growth, migration, and invasion. ATR inhibitors were more effective at killing breast cancer cells with intact RNF126 due to replication stress compared with the corresponding cells with RNF126 knockdown. Cyclin-dependent kinase 2 (CDK2) was involved in regulating replication stress in breast cancer cells with intact RNF126.ConclusionA high level of expression of RNF126 in early breast cancer patients without lymph node metastases may indicate a high-risk type of metastatic disease, possibly due to RNF126, which may increase breast cancer cell proliferation and invasion. RNF126-expressing breast cancer cells exhibit CDK2-mediated replication stress that makes them potential targets for ATR inhibitors.

Glycosylation Alterations in Cancer Cells, Prognostic Value of Glycan Biomarkers and Their Potential as Novel Therapeutic Targets in Breast Cancer.

Although we are lately witnessing major improvements in breast cancer treatment and patient outcomes, there is still a significant proportion of patients not receiving efficient therapy. More precisely, patients with triple-negative breast cancer or any type of metastatic disease. Currently available prognostic and therapeutic biomarkers are not always applicable and oftentimes lack precision. The science of glycans is a relatively new scientific approach to better characterize malignant transformation and tumor progression. In this review, we summarize the most important information about glycosylation characteristics in breast cancer cells and how different glycoproteins and enzymes involved in glycosylation could serve as more precise biomarkers, as well as new therapeutic targets.

BRCA1 overexpression attenuates breast cancer cell growth and migration by regulating the pyruvate kinase M2-mediated Warburg effect via the PI3K/AKT signaling pathway.

This work explored the mechanism of the effect of breast-cancer susceptibility gene 1 (BRCA1) on the metabolic characteristics of breast cancer cells, including the Warburg effect and its specific signaling. We transfected MCF-7 cells with a BRCA1-encoding LXSN plasmid or PKM2 siRNA and examined cancer cell metabolism using annexin V staining, inhibitory concentration determination, Western blotting, glucose uptake and lactic acid content measurements, and Transwell assays to assess glycolytic activity, cell apoptosis, and migration, and sensitivity to anti-cancer treatment. The BRCA1-expressing MCF-7 cells demonstrated low PKM2 expression and decreased glycolytic activity (downregulated hexokinase 2 (HK2) expression, upregulated isocitrate dehydrogenase 1 (IDH1) expression, and reduced O2 and glucose consumption and lactate production) via regulation of PI3K/AKT pathway compared with the empty LXSN group. BRCA1 transfection slightly increased apoptotic activity, decreased cell migration, and increased the IC50 index for doxorubicin, paclitaxel, and cisplatin. Inhibiting PKM2 using siRNA attenuated the IC50 index for doxorubicin, paclitaxel, and cisplatin compared with the control. Inhibiting PKM2 activated PI3K/AKT signaling, increased apoptosis, and decreased MCF-7 cell migration. Our data suggest that BRCA1 overexpression reverses the Warburg effect, inhibits cancer cell growth and migration, and enhances the sensitivity to anti-cancer treatment by decreasing PKM2 expression regulated by PI3K/AKT signaling. These novel metabolic findings represent a potential mechanism by which BRCA1 exerts its inhibitory effect on breast cancer.