Human Mammary Epithelial Cell Line Research Articles

Abstract PO1-16-04: Targeting PKMYT1 Kinase as a Therapeutic Strategy for Treatment of Triple Negative Breast Cancer with Low Molecular Weight Cyclin E (LMW-E) Expression

Abstract Purpose: Low molecular weight isoforms of cyclin E (LMW-E) have been implicated in various human cancers, including triple negative breast cancer (TNBC), and are associated with a poor prognosis. However, targeted therapies for TNBC based on biomarkers are currently lacking. This study aims to investigate LMW-E as a potential therapeutic target in TNBC and evaluate the efficacy of RP-6306, a selective inhibitor of the Protein Kinase, Membrane Associated Tyrosine/Threonine 1 (PKMYT1), in LMW-E-positive breast tumors. Experimental Design: Immunohistochemical (IHC) analysis was performed on pre-treatment tumor specimens from TNBC patients (n=36) to assess the correlation between LMW-E expression, CDK1 phosphorylation at Threonine 14 (pT14), and pathologic complete response to neoadjuvant chemotherapy. LMW-E inducible human mammary epithelial cells (hMEC) and breast cancer cell lines were used to investigate the regulatory effect of LMW-E on PKMYT1, the kinase responsible for CDK1 phosphorylation at T14, and the response to RP-6306, a first in-class and selective inhibitor of PKMYT1. Patient-derived xenograft (PDX) models and transgenic mouse mammary tumor virus (MMTV) models of TNBC expressing human LMW-E (hLMW-E) were also utilized to assess LMW-E as a biomarker for predicting response to RP-6306. Results. Analysis of TNBC tumor biopsies revealed a significant positive correlation between LMW-E expression and CDK1 pT14, and both biomarkers were associated with a lack of pathological complete response to neoadjuvant chemotherapy. In vitro results using LMW-E inducible hMECs and breast cancer cell lines demonstrated that LMW-E up-regulates PKMYT1 and CDK1 pT14, acting as a PKMYT1 binding protein and enhancing PKMYT1 protein stability. High LMW-E protein levels predicted a favorable response to RP-6306, resulting in the accumulation of sub-G1 and polyploid cells, decreased tolerance to replication stress, increased DNA damage, chromosomal breakage, and apoptosis. In vivo treatment of TNBC PDX models and hLMW-E transgenic tumors with RP-6306 resulted in a significant reduction in tumor volume only in mice harboring high LMW-E tumors, while low cyclin E models showed no response. Immunohistochemical analysis confirmed increased γ-H2AX and decreased CDK1-pT14 and Ki67 levels, indicating the efficacy of RP-6306 in both PDX and transgenic models. Conclusion: This study highlights the regulatory axis from LMW-E to PKMYT1 and its predictive value for pathological complete response in TNBC patients receiving neoadjuvant chemotherapy. The selective PKMYT1 kinase inhibitor RP-6306 consistently induced DNA damage and inhibited tumor growth in in vitro and in vivo pre-clinical breast tumor models. Co-expression of LMW-E and CDK1-pT14 in TNBC can be used to stratify patients whose tumors are likely to respond to RP-6306, emphasizing its therapeutic significance. Citation Format: Mi Li, Amriti Lulla, Cansu Karakas, Spiridon Tsavaschidis, Yan Wang, Tuyen Nguyun, Tuyen Bui, Gary Marshall, Kelly Hunt, Khandan Keyomarsi. Targeting PKMYT1 Kinase as a Therapeutic Strategy for Treatment of Triple Negative Breast Cancer with Low Molecular Weight Cyclin E (LMW-E) Expression [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 PO1-16-04.

Abstract 265: Reconstructing the early steps of breast tumor initiation

Abstract Breast cancer screening programs, detect not only the early stages of the disease but also various preneoplastic lesions which are very difficult to predict if and when they may develop into cancer. This uncertainty can lead to over-diagnosis, over-treatment and stress for millions of screened women. As consequence, discovering reliable biomarkers of this evolution could make it possible to monitor these patients appropriately and propose an effective prevention strategy. To meet this challenge, we urgently need to better understand the mechanisms that regulate human mammary homeostasis during early steps of tumor initiation. The hierarchy and the composition of human mammary epithelium, composed of stem, myoepithelial, luminal progenitors and mature luminal cells, are complex. This complexity raises the question of whether a given mammary epithelial cell is equally likely to be the cell-of-origin of breast cancer. Interestingly, increasing evidences show that disruption of lineage integrity can be a precursor of breast tumor initiation, and the basal and the luminal lineages respond differently to a given oncogenic stress and may each follow their own rule towards malignant transformation. These results strongly suggest that each lineage may have its own pliancy to be transformed by a given oncogene, hijacking the inter-tumoral heterogeneity observed in breast cancers. The objectives of this study are to develop a model to reconstruct the early steps of breast tumor initiation and understand the interplay between the initiating oncogenic event and the cell-of-origin. To answer these questions, we used a human mammary epithelial cell lines (HME) that maintains a cellular hierarchy with mammary stem cells (MaSC) and luminal cells (LC). Upon oncogenic expression of HRASG12V or c-Myc, we observed different modifications of cell homeostasis, with altered proportions of the lineages populations in the cell line. Depending on the oncogenic stress induced, we also demonstrated a modification in the morphology and the cellular composition of HME organoids, as well as in the capacity to form tumors. HRASG12V induces increase of MaSC compartment, formation of more branched organoids and generate aggressive basal-like tumors. Conversely, c-MYC leads to an almost loss of MaSC and formation of more proliferative unbranched organoid and generate tumors with limited growth. To address more precisely how cell-of-origin and lineage plasticity influence malignant transformation, we are developing for the first time a lineage tracing model in human mammary epithelium with HME. Moreover, a single cell RNA-seq was performed at different early time points during HME cellular differentiation in homeostasis and upon oncogenic stress to decipher the molecular mechanisms that underpin the very earliest steps of breast tumor initiation. Citation Format: Anaïs Grandon, Shuheng Lin, Martin Castagné, Julien Wicinski, Olivier Rosnet, Christophe Ginestier, Emmanuelle Charafe-Jauffret. Reconstructing the early steps of breast tumor initiation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 265.

Abstract A084: DEK overexpression in the murine mammary gland promotes epithelial hyperplasia

Abstract Introduction: Breast cancer (BC) remains a leading cause of cancer-associated mortality for women in the USA, which makes it critically important to identify and study molecular drivers of pathogenesis. We have previously identified the chromatin modifying DEK protein to have oncogenic properties. DEK is a histone H3 chaperone that is over-expressed in over 60% of breast cancers, particularly triple negative breast cancers, and is associated with poor survival. To date, all studies regarding the role of DEK in BC have manipulated DEK expression in cultured immortalized MCF10A human mammary epithelial cells and BC cell lines. However, the oncogenic functions of DEK in vivo and in normal mammary epithelium have remained unexplored. Methods: We utilized a tetracycline-off regulated, DEK overexpressing (DEK-OE) transgenic mouse model that targets mammary epithelium through the mouse mammary tumor virus (MMTV) promoter. We subsequently performed bulk RNA-Seq transcriptomic analyses, western blotting, and both histological and morphological assessments of control vs. DEK-OE mammary gland tissue to identify the oncogenic effects of DEK over-expression in vivo. Results: Bulk RNA sequencing and gene ontology analyses identified cell cycle regulation as a significantly upregulated biological process in DEK-OE versus control glands. Subsequent studies confirmed upregulation of proteins that promote the G1-S cell cycle transition including cyclins A and D and CDKs 2, 4, and 6 as well as increased numbers of Ki67+ cells. We also observed down-regulation of genes that inhibit entry the G1-S transition, such as p21 and p27. This pro-proliferative molecular status correlated with the development of mammary gland hyperplasia. Importantly, in silico analyses demonstrated gene correlations between DEK and cell cycle regulators that were also evident in human breast cancers. One potential mechanism for this transcriptional deregulation is that we identified increased histone H3K27me3 epigenetic modifications in DEK-OE cells, in both mouse and human models, which may occur through EZH2 activity. Conclusions: Combined, our work indicates that DEK is not a tumor initiator, but its oncogenic activities are likely due to its ability to promote proliferation of mammary epithelial cells. Furthermore, we report a novel function for DEK in the epigenetic regulation of histone H3 K27 trimethylation, which is mediated by the well-known EZH2 oncogene in triple negative breast cancers. Citation Format: Megan Johnstone, Ashley Leck, Taylor Lange, Lisa Privette Vinnedge. DEK overexpression in the murine mammary gland promotes epithelial hyperplasia [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Breast Cancer Research; 2023 Oct 19-22; San Diego, California. Philadelphia (PA): AACR; Cancer Res 2024;84(3 Suppl_1):Abstract nr A084.

New pyrrolidine-carboxamide derivatives as dual antiproliferative EGFR/CDK2 inhibitors.

Cancer is one of the leading causes of mortality worldwide, making it a public health concern. A novel series of pyrrolidine-carboxamide derivatives 7a-q were developed and examined in a cell viability assay utilizing a human mammary gland epithelial cell line (MCF-10A), where all the compounds exhibited no cytotoxic effects and more than 85% cell viability at a concentration of 50 μM. Antiproliferative activity was evaluated invitro against four panels of cancer cell lines A-549, MCF-7, Panc-1, and HT-29. Compounds 7e, 7g, 7k, 7n, and 7o were the most active as antiproliferative agents capable of triggering apoptosis. Compound 7g was the most potent of all the derivatives, with a mean IC50 of0.90 μM compared to IC50 of 1.10 μM for doxorubicin. Compound 7g inhibited A-549 (epithelial cancer cell line), MCF-7 (breast cancer cell line), and HT-29 (colon cancer cell line) more efficiently than doxorubicin. EGFR inhibitory assay results of 7e, 7g, 7k, 7n, and 7o demonstrated that the tested compounds inhibited EGFR with IC50 values ranging from 87 to 107 nM in comparison with the reference drug erlotinib (IC50 = 80 nM). 7e, 7g, 7k, 7n, and 7o inhibited CDK2 efficiently in comparison to the reference dinaciclib (IC50 = 20 nM), with IC50 values ranging from 15 to 31 nM. The results of inhibitory activity assay against different CDK isoforms revealed that the tested compounds had preferential inhibitory activity against the CDK2 isoform.

Sulfated polysaccharides of Laetiporus sulphureus fruiting bodies exhibit anti-breast cancer activity through cell cycle arrest, apoptosis induction, and inhibiting cell migration

Ethnopharmacological relevanceLaetiporus sulphureus has long been used as an edible and medicinal mushroom in Asia, America, and Europe. Its fruiting bodies are widely used in folk medicine for treating cancer, gastric diseases, cough, and rheumatism. Polysaccharides are an important bioactive component of mushrooms. In nature, sulfated polysaccharides have never been reported in mushrooms. Furthermore, there is no information on differences in physicochemical properties and anti-breast cancer activities between polysaccharides (PS) and sulfated polysaccharides (SPS) of L. sulphureus. Aim of the studyThis study aimed to investigate the physicochemical properties of PS and SPS isolated from fruiting bodies of L. sulphureus and examine their anti-proliferative effects and mechanism(s) of action on MDA-MB-231 breast cancer cells. MethodsPolysaccharides (PS) were isolated using hot water and ethanol precipitation methods. Sulfated polysaccharides (SPS) were isolated by the papain-assisted hydrolysis method. Physicochemical properties comprising sugar, protein, uronic acid, and sulfate contents, and molecular weight, monosaccharide composition, and structural conformation were analyzed on PS and SPS. In the anti-cancer study, a triple-negative breast cancer cell line (MDA-MB-231) and a normal human mammary epithelial cell line (H184B5F5/M10) were used to evaluate the anti-proliferative activity of PS and SPS, and their mechanism(s) of action. ResultsThe results showed that SPS, which had higher sulfate and protein contents and diversified monosaccharide composition, exhibited more potent anti-proliferative activity against MDA-MB-231 cells than PS. Furthermore, it had a selective cytotoxic effect on breast cancer cells but not the normal cells. SPS induced cell cycle arrest at G0/G1 phase via down-regulating CDK4 and cyclin D1 and up-regulating p21 protein expression. Breast cancer cell apoptosis was not observed until 72 h after SPS treatment. In addition, SPS also markedly inhibited breast cancer cell migration. ConclusionThis study demonstrates that SPS exhibited selective cytotoxicity and was more potent than PS in inhibiting MDA-MB-231 cell proliferation. The contents of sulfate and protein, and monosaccharide composition could be the main factors affecting the anti-breast cancer activity of L. sulphureus SPS.

An Increase in HSF1 Expression Directs Human Mammary Epithelial Cells toward a Mesenchymal Phenotype.

HSF1 is a well-known heat shock protein expression regulator in response to stress. It also regulates processes important for growth, development or tumorigenesis. We studied the HSF1 influence on the phenotype of non-tumorigenic human mammary epithelial (MCF10A and MCF12A) and several triple-negative breast cancer cell lines. MCF10A and MCF12A differ in terms of HSF1 levels, morphology, growth in Matrigel, expression of epithelial (CDH1) and mesenchymal (VIM) markers (MCF10A are epithelial cells; MCF12A resemble mesenchymal cells). HSF1 down-regulation led to a reduced proliferation rate and spheroid formation in Matrigel by MCF10A cells. However, it did not affect MCF12A proliferation but led to CDH1 up-regulation and the formation of better organized spheroids. HSF1 overexpression in MCF10A resulted in reduced CDH1 and increased VIM expression and the acquisition of elongated fibroblast-like morphology. The above-mentioned results suggest that elevated levels of HSF1 may direct mammary epithelial cells toward a mesenchymal phenotype, while a lowering of HSF1 could reverse the mesenchymal phenotype to an epithelial one. Therefore, HSF1 may be involved in the remodeling of mammary gland architecture over the female lifetime. Moreover, HSF1 levels positively correlated with the invasive phenotype of triple-negative breast cancer cells, and their growth was inhibited by the HSF1 inhibitor DTHIB.

Expression of LINC00461 in breast cancer cells and its modulatory effect on miR-607/SLCLA3 axis

Purpose: To investigate the role and mechanisms of action of long non-coding RNA (lncRNA) (LINC00461) in breast cancer. 
 Methods: Human breast cancer cell lines and normal mammary epithelial cell lines as well as their corresponding negative controls (NC) were cultured and co-transfected with Lipofectamine 3000. Expressions of LINC00461 and miR-607 were analyzed by quantitative real-time polymerase chain reaction (qRT-PCR), while the SLC1A3 level was evaluated by western blot. The role of LINC00461 in cell proliferation, apoptosis, cycle arrest, glycolysis, and chemoresistance was determined by MTT, colony formation, flow cytometry, and ELISA assays. 
 Results: The LINC00461 level was overexpressed in breast cancer cell lines (p ˂ 0.05). Knockdown of LINC00461 in MCF-7 cells inhibited cell viability (p ˂ 0.01) and the degree of colony formation (p ˂ 0.001), induced cell apoptosis (p ˂ 0.001) and cycle arrest (p ˂ 0.01), and suppressed glucose consumption (p ˂ 0.001), lactate production (p ˂ 0.001), LDHA activity (p ˂ 0.05) and cisplatin sensitivity (p ˂ 0.05). Overexpression of LINC00461 in MDA-MB-468 cells resulted in reverse outcomes. LINC00461 positively regulated the expression of SLC1A3 via miR-607 in breast cancer cells. It was mechanistically established that LINC00461 is bound to miR-607 and miR-607 bound to SLC1A3, and this was confirmed by luciferase assay. 
 Conclusion: LINC00461 induces cell proliferation, cycle arrest, glycolysis, and chemoresistance by modulating miR-607/SLC1A3 axis in breast cancer. The results lay the theoretical basis for monitoring and therapy of breast cancer.

Differences in the Cell Type-Specific Toxicity of Diamond Nanoparticles to Endothelial Cells Depending on the Exposure of the Cells to Nanoparticles.

Diamond nanoparticles are considered to be one of the most cytocompatible carbon nanomaterials; however, their toxicity varies significantly depending on the analysed cell types. The aim was to investigate the specific sensitivity of endothelial cells to diamond nanoparticles dependent on exposure to nanoparticles. Diamond nanoparticles were characterized with Raman spectroscopy, Fourier-transform infrared spectroscopy (FTIR) and dynamic light scattering (DLS). Toxicity of diamond nanoparticles was assessed for endothelial cells (HUVEC), human mammary epithelial cells (HMEC) and HS-5 cell line. The effect of diamond nanoparticles on the level of ROS, NO, NADPH and protein synthesis of angiogenesis-related proteins of endothelial cells was evaluated. Our studies demonstrated severe cell type-specific toxicity of diamond nanoparticles to endothelial cells (HUVEC) depending on nanoparticle surface interaction with cells. Furthermore, we have assessed the effect on cytotoxicity of the bioconjugation of nanoparticles with a peptide containing the RGD motive and a serum protein corona. Our study suggests that the mechanical interaction of diamond nanoparticles with the endothelial cell membranes and the endocytosis of nanoparticles lead to the depletion of NADPH, resulting in an intensive synthesis of ROS and a decrease in the availability of NO. This leads to severe endothelial toxicity and a change in the protein profile, with changes in major angiogenesis-related proteins, including VEGF, bFGF, ANPT2/TIE-2, and MMP, and the production of stress-related proteins, such as IL-6 and IL-8. We confirmed the presence of a relationship between the toxicity of diamond nanoparticles and the level of cell exposure to nanoparticles and the nanoparticle surface. The results of the study give new insights into the conditioned toxicity of nanomaterials and their use in biomedical applications.

Comparison of transcriptome alterations induced by pendimethalin or its commercial formulation Stomp Aqua in human MCF-7, MCF-10 A and MCF-12 A mammary epithelial cells

ObjectiveThe toxicology of herbicides, which are currently in use is under-explored. One highly used but under investigated herbicide is pendimethalin. Here we mined high-throughput data from the US National Toxicology Program (NTP) to identify whether pendimethalin possesses an estrogenic capability in human cells. We also evaluated effects of pendimethalin and its reference commercial formulated herbicide Stomp Aqua on the transcriptome profile of three human mammary epithelial cell lines, cancerous MCF-7 and non-cancerous MCF-10 A and MCF-12 A to see whether this compound could have endocrine disrupting effects and if co-formulants present in the commercial formulation could amplify its toxicity.ResultsThe data mined from the US NTP database suggests that pendimethalin activates estrogen receptors at a concentration of approximately 10?M. MCF-7, MCF-10A and MCF-12A cells were exposed to 10 ?M pendimethalin and Stomp Aqua at an equivalent concentration. Transcriptome analysis showed changes in gene expression patterns implying that pendimethalin affected ubiquitin-mediated proteolysis and the function of the spliceosome. The formulated pendimethalin product Stomp Aqua gave comparable effects suggesting pendimethalin was responsible for the observed transcriptome alterations. Given the lack of information on the exposure to this pesticide, our study prompts the need for biomonitoring studies, especially under occupational use scenarios, to understand if low level exposure to pendimethalin could have endocrine disrupting effects on populations exposed to this compound. A deeper understanding of the exposure and mechanisms of action of this endocrine-disrupting pesticide is needed.

Activation of an actin signaling pathway in pre-malignant mammary epithelial cells by P-cadherin is essential for transformation.

Alterations in the expression or function of cell adhesion molecules have been implicated in all steps of tumor progression. Among those, P-cadherin is highly enriched in basal-like breast carcinomas, playing a central role in cancer cell self-renewal, collective cell migration and invasion. To establish a clinically relevant platform for functional exploration of P-cadherin effectors in vivo, we generated a humanized P-cadherin Drosophila model. We report that actin nucleators, Mrtf and Srf, are main P-cadherin effectors in fly. We validated these findings in a human mammary epithelial cell line with conditional activation of the SRC oncogene. We show that, prior to promoting malignant phenotypes, SRC induces a transient increase in P-cadherin expression, which correlates with MRTF-A accumulation, its nuclear translocation and the upregulation of SRF target genes. Moreover, knocking down P-cadherin, or preventing F-actin polymerization, impairs SRF transcriptional activity. Furthermore, blocking MRTF-A nuclear translocation hampers proliferation, self-renewal and invasion. Thus, in addition to sustaining malignant phenotypes, P-cadherin can also play a major role in the early stages of breast carcinogenesis by promoting a transient boost of MRTF-A-SRF signaling through actin regulation.

Design, synthesis, docking and mechanistic studies of new thiazolyl/thiazolidinylpyrimidine-2,4-dione antiproliferative agents

In this article, we display on the synthesis and biological evaluation of a new series of thiazolylpyrimidine 3a-l and thiazolidinylpyrimidine derivatives 5a-e. The structures of the new compounds were confirmed by using different spectral techniques including NMR, IR, mass spectroscopy in addition to elemental analyses. The cell viability of the new compounds was assessed against normal human mammary gland epithelial (MCF-10A) cell line. Data revealed that none of the compounds examined exhibited cytotoxic effects, and the cell viability for the compounds examined at 50 µM was greater than 87%. The antiproliferative activity of 3a-l and 5a-e was evaluated against four human cancer cell lines where the compounds showed promising activity. The most potent derivatives were compounds 3a, 3c, 3f, 3i, and 5b with GI50 values ranging from 0.90 µM to 1.70 µM against the four cancer cell lines in comparison to doxorubicin (GI50 = 1.10 µM). Compounds 3a, 3c and 3i showed potent antiproliferative activity with dual inhibitory action against EGFR and BRAFV600E. Compounds 3a, 3c, and 3i demonstrated promising AutoDock scores towards EGFR and BRAFV600E with values of − 9.1 and − 8.6, −9.0 and − 8.5, and − 8.4 and − 8.0 kcal/mol, respectively. The physicochemical and pharmacokinetic characteristics of 3a, 3c, and 3i were anticipated, demonstrating their oral bioavailability.

Downregulation of Mucin1 in Cancer Cells is Associated with Modulation of Calcium Signalling Pathways and Alteration in Procoagulant Related Activity

Background Intracellular calcium ions play an essential role in regulating numerous physiological functions by acting as a second messenger in signal transduction pathways. Alterations in calcium signaling are also implicated in several pathological conditions including cancer. Aim The purpose of this study is to investigate whether MUC1, a well-established tumor marker, plays a role in modulating calcium signalling in cancer cells. Methods MUC1 knockdown breast cancer MCF-7 cells were used to investigate whether the overexpression of MUC1 by cancer cells has an influence on calcium signalling pathways, by determining the level of a range of calcium signalling proteins and the dynamics of intracellular calcium mobilization as well as the cellular effects induced by calcium treatment. The investigation was also extended to normal human mammary epithelial, human breast and pancreatic cancer cell lines, which express different levels of MUC1. Result MUC1 downregulation altered the aberrant expression of several calcium transporter proteins in MCF-7 cancer cells. The level of each of these calcium signaling pathways proteins was correlated to MUC1 level in normal human mammary epithelial, human breast and pancreatic cancer cell lines. Consequently, a number of proteins whose activities are calcium dependent such as p-CaMKII, and pro-coagulant proteins Va, Xa and thrombin were found to be reduced in MUC1 downregulated MCF-7 cells. In addition, the effect of thrombin on calcium mobilization and the cleavage of the thrombin receptors was also reduced in MUC1 downregulated MCF-7 cells. Conclusion The downregulation of MUC1 is capable of modulating calcium cellular effects via alteration in the expression of calcium signalling proteins and by impacting calcium induced initiation of procoagulant activity, which is capable of influencing the effect of thrombin on cancer cells. Such properties contribute to another crucial role for MUC1 within the signalling network associated with tumorigenesis.

A pyroptosis-related gene signature for prognostic and immunological evaluation in breast cancer.

Pyroptosis exerts an undesirable impact on the clinical outcome of breast cancer. Since any single gene is insufficient to be an appropriate marker for pyroptosis, our aim is to develop a pyroptosis-related gene (PRG) signature to predict the survival status and immunological landscape for breast cancer patients. The information of breast cancer patients was retrieved from The Cancer Genome Atlas (TCGA) and the Gene Expression Omnibus (GEO) databases. Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to verify the gene expressions of this signature in breast cancer. Its prognostic value was evaluated by univariate Cox analysis, least absolute shrinkage and selection operator (LASSO) regression analysis, receiver operating characteristics (ROCs), univariate/multivariate analysis, and nomogram. Analyses of Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were performed to explore its potential biological function in breast cancer. The potential correlation between this signature and tumor immunity was revealed based on single sample gene set enrichment analysis (ssGSEA), ESTIMATE and CIBERSORT algorithms. A PRG signature containing GSDMC, GZMB, IL18, and TP63 was created in a TCGA training cohort and validated in two validation GEO cohorts GSE58812 and GSE37751. Compared with a human mammary epithelial cell line MCF-10A, the expression levels of GSDMC, GZMB and IL18 were upregulated, while TP63 was found with lower expression level in breast cancer cells SK-BR-3, BT-549, MCF-7, and MDA-MB-231 using RT-qPCR assay. Based on univariate and multivariate Cox models, ROC curve, nomogram as well as calibration curve, it was revealed that this signature with high-risk score could independently predict poor clinical outcomes in breast cancer. Enrichment analyses demonstrated that the involved mechanism was tightly linked to immune-related processes. SsGSEA, ESTIMATE and CIBERSORT algorithms further pointed out that the established model might exert an impact on immune cell abundance, immune cell types and immune-checkpoint markers. Furthermore, individuals with breast cancer responded differently to these therapeutic agents based on this signature. Our data suggested that this PRG signature with high risk was tightly associated with impaired immune function, possibly resulting in an unfavorable outcome for breast cancer patients.

Therapeutic Evaluation of Ethanolic Bee Pollen Extract from Malaysian Stingless Bee in MCF-7 and MCF-10A Cell Lines

Bee pollen is a complete food containing comprehensive nutrients and therapeutic properties that could eliminate free radicals. Three stingless bee species native to Malaysia were used to prepare bee pollen ethanolic extracts (BPE): Geniotrigona thoracica, Heterotrigona itama, and Tetrigona apicalis. The methodology used in this study was a trypan blue exclusion assay for cell proliferation activity in cultured breast adenocarcinoma human cell lines (MCF-7) and mammary epithelial human cell lines (MCF-10A). In addition, the therapeutic index (TI) was analyzed to assess the relative antiproliferative activity of BPE on cancer versus normal cells. Geniotrigona thoracica, BPE exhibited the highest therapeutic index (TI = 3.12) compared to H. itama (TI = 1.16) and T. apicalis (TI = 0.90) BPE. Each species represents different bioactive compounds due to different pollen foraging activities. Therefore, the highest TI species (G. thoracica) could be a potential candidate to be developed as a potential chemotherapeutic agent.

Borealin-Derived Peptides as Survivin-Targeting Cancer Imaging and Therapeutic Agents.

Survivin is overexpressed in most cancer cells but is rarely expressed in normal adult tissues. It is associated with poor prognosis and resistance to radiation therapy and chemotherapy. In this study, we designed and synthesized borealin-derived small peptides (Bor peptides) to function as survivin-targeting agents for the diagnosis and treatment of cancers. These peptides exhibited binding affinities for recombinant human survivin (Kd = 49.6-193 nM), with Bor65-75 showing the highest affinity (Kd = 49.6 nM). Fluorescence images of fluorescein isothiocyanate-labeled Bor65-75 showed its co-localization with survivin expression in the human pancreatic cancer cell line, MIA PaCa-2. In the WST-1 assay, cell penetrable nona-d-arginine-conjugated Bor65-75 (r9-Bor65-75) inhibited the growth of MIA PaCa-2 cells and MDA-MB-231 cells (89 and 88% inhibition at 10 μM, respectively), whereas it had almost no effect on the human mammary epithelial cell line, MCF-10A, that inherently does not have high survivin expression. Flow cytometry with annexin V and propidium iodide staining revealed that r9-Bor65-75 induced apoptosis in MIA PaCa-2 cells in a dose-dependent manner. An increase in cleaved poly ADP-ribose polymerase protein expression was observed in MIA PaCa-2 cells exposed to r9-Bor65-75 by western blotting, suggesting that r9-Bor65-75 inhibits cell proliferation by inducing apoptosis. In vivo, r9-Bor65-75 significantly suppressed tumor growth in MIA PaCa-2 xenograft mice, without any marked weight loss. Hence, Bor peptides are promising candidates for the development of cancer imaging and anticancer agents targeting survivin.

AJAP1 Gene Silencing Alters Protein Expression in Epithelial Cells

IntroductionThe epicardial layer of the heart is formed during cardiovascular development from a transitory structure known as the proepicardium (PE). Proepicardial cells migrate out of the PE to surround and adhere to the myocardium to form a layer of epithelial cells that compose the epicardium. A subset of the epicardial cells delaminate and migrate into the subepicardial space where they undergo epithelial‐mesenchymal transition (EMT) to become epicardial‐derived cells (EPDCs). These EPDCs invade the myocardium and differentiate into a subset of cells that make up the coronary vessels. During this entire process, the epicardium receives input from several transcription factors including Tbx5. Mice with a conditional deletion of Tbx5 exhibit impaired epicardium formation and coronary vessel development. Tbx5‐deficient mouse hearts have a significant decrease in mRNA expression of adherens junction associated protein (Ajap1). Our studies show that knockdown of endogenous AJAP1 (AJAP1 KD) mRNA expression in epithelial cells leads to increased cell adhesion, reduced cell migration, enhanced expression of epithelial markers of EMT, and altered expression of transcripts associated with adherens junctions, tight junctions and EMT. Specifically, our qPCR array data shows a significant alteration in ZEB2 mRNA expression in AJAP1 KD cells versus negative control cells.Study ObjectiveThe goal of this study was to examine the role of AJAP1 in regulating protein expression of ZEB2 as it may be necessary for epicardium formation. Based on previous cell function and mRNA expression data, we hypothesize that the ZEB2 protein is an important functional mediator of AJAP1 in epithelial cells for undergoing EMT.MethodsWe utilized the primary human mammary epithelial cell line (HMEpiC) as an in vitro system to examine contributions of AJAP1 to epithelial cell biology. We silenced AJAP1 mRNA expression in HMEpiCs using small interfering RNAs and examined protein expression of ZEB2. We compared ZEB2 expression in negative control versus AJAP1 KD HMEpiCs.ResultsReduced expression of AJAP1transcripts produced noticeable changes in protein expression of ZEB2 in epithelial cells, and it had significant effects on expression of adherens junction‐related transcripts. Western blot analysis revealed an increase in ZEB2 protein expression in AJAP1 KD versus negative control HMEpiCs.ConclusionOur data indicate that AJAP1 contributes to epithelial cell function, and it does this potentially by mediating ZEB2 protein expression. ZEB2 is known to regulate EMT, which is a biological process that is crucial for the formation of the epicardium and its subsequent formation of the coronary vasculature.

Targeting Cell Death Mechanism Specifically in Triple Negative Breast Cancer Cell Lines.

Triple negative breast cancer (TNBC) is currently associated with a lack of treatment options. Arsenic derivatives have shown antitumoral activity both in vitro and in vivo; however, their mode of action is not completely understood. In this work we evaluate the response to arsenate of the double positive MCF-7 breast cancer cell line as well as of two different TNBC cell lines, Hs578T and MDA-MB-231. Multimodal experiments were conducted to this end, using functional assays and microarrays. Arsenate was found to induce cytoskeletal alteration, autophagy and apoptosis in TNBC cells, and moderate effects in MCF-7 cells. Gene expression analysis showed that the TNBC cell lines’ response to arsenate was more prominent in the G2M checkpoint, autophagy and apoptosis compared to the Human Mammary Epithelial Cells (HMEC) and MCF-7 cell lines. We confirmed the downregulation of anti-apoptotic genes (MCL1, BCL2, TGFβ1 and CCND1) by qRT-PCR, and on the protein level, for TGFβ2, by ELISA. Insight into the mode of action of arsenate in TNBC cell lines it is provided, and we concluded that TNBC and non-TNBC cell lines reacted differently to arsenate treatment in this particular experimental setup. We suggest the future research of arsenate as a treatment strategy against TNBC.

Influence of cellular models and individual factor in the biological response to chest CT scan exams

BackgroundWhile computed tomography (CT) exams are the major cause of medical exposure to ionising radiation, there is increasing evidence that the potential radiation-induced risks must be documented. We investigated the impact of cellular models and individual factor on the deoxyribonucleic acid double-strand breaks (DSB) recognition and repair in human fibroblasts and mammary epithelial cells exposed to current chest CT scan conditions.MethodTwelve human primary fibroblasts and four primary human mammary epithelial cell lines with different levels of radiosensitivity/susceptibility were exposed to a standard chest CT scan exam using adapted phantoms. Cells were exposed to a single helical irradiation (14.4 mGy) or to a topogram followed, after 1 min, by one single helical examination (1.1 mGy + 14.4 mGy). DSB signalling and repair was assessed through anti-γH2AX and anti-pATM immunofluorescence.ResultsChest CT scan induced a significant number of γH2AX and pATM foci. The kinetics of both biomarkers were found strongly dependent on the individual factor. The topogram may also influence the biological response of radiosensitive/susceptible fibroblasts to irradiation. Altogether, our findings show that a chest CT scan exam may result in 2 to 3 times more unrepaired DSB in cells from radiosensitive/susceptible patients.ConclusionsBoth individual and tissue factors in the recognition and repair of DSB after current CT scan exams are important. Further investigations are needed to better define the radiosensitivity/susceptibility of individual humans.

Mass cytometric and transcriptomic profiling of epithelial-mesenchymal transitions in human mammary cell lines

Epithelial-mesenchymal transition (EMT) equips breast cancer cells for metastasis and treatment resistance. However, detection, inhibition, and elimination of EMT-undergoing cells is challenging due to the intrinsic heterogeneity of cancer cells and the phenotypic diversity of EMT programs. We comprehensively profiled EMT transition phenotypes in four non-cancerous human mammary epithelial cell lines using a flow cytometry surface marker screen, RNA sequencing, and mass cytometry. EMT was induced in the HMLE and MCF10A cell lines and in the HMLE-Twist-ER and HMLE-Snail-ER cell lines by prolonged exposure to TGFβ1 or 4-hydroxytamoxifen, respectively. Each cell line exhibited a spectrum of EMT transition phenotypes, which we compared to the steady-state phenotypes of fifteen luminal, HER2-positive, and basal breast cancer cell lines. Our data provide multiparametric insights at single-cell level into the phenotypic diversity of EMT at different time points and in four human cellular models. These insights are valuable to better understand the complexity of EMT, to compare EMT transitions between the cellular models used here, and for the design of EMT time course experiments.

Replacement of hydrochloride in metformin hydrochloride with caprylic acid to investigate its effects on MCF-7 and MDA-MB-231 breast cancer cell lines

AimsMetformin hydrochloride is a highly hydrophilic molecule with low permeability. In the present study, to develop an effective drug to treat the metastatic breast cancer, metformin caprylic acid was synthesized using metformin hydrochloride as a permeable agent. Main methodsThe cytotoxic effects of various concentrations of metformin caprylic acid and metformin hydrochloride (0 to 20 mM) on MCF-7 and MDA-MB-231 breast cancer cells and MCF-10A human mammary epithelial cell line were assessed by the MTT assay. Furthermore, Annexin V, PI staining, and cell flow cytometry assays were performed to evaluate the apoptotic effects. The invasion and migration ability of these cells were evaluated following treatment with equal concentration (3 mM) of the two compounds. Key findingsThe treatment of tested cell lines with an equal concentration of two chemicals decreased cell viability in a time and dose-dependent manner, where in all cases, metformin caprylic acid caused significantly more apoptosis and invasion inhibition than that of metformin hydrochloride (*p < 0.05). Chemical structures of both compounds were confirmed by FTIR and 1H NMR, 13C NMR. Both chemicals inhibited the migration of MCF-7 and MCF-10A cells, but had no effect on MDA-MB-231 migration. All data are expressed as mean ± SD (n = 3). SignificanceIt seems that in an equal concentration, the similarity of the hydrophobic tail of caprylic acid to the cell membrane improves its entrance, while decreasing the drug excretion.