Human Breast Cancer Stem Cells Research Articles

<span>Identification of the potential compounds for inhibition CD44 target of human breast cancer stem cells by docking method</span>

In a recent cell-based assay, it has been demonstrated that the F-19848A compound inhibits the binding of hyaluronan to the CD44 receptor, which is a cell-surface glycoprotein and a receptor for hyaluronan, a major component of the tumor extracellular matrix. The interaction between CD44 and hyaluronan has been shown to promote breast cancer metastasis according to evidence. In this study, the PubChem database contains more than 112 million compounds. This data is inputted for virtual screening find out top hits by combining Lipinski’s rule and docking method. With 20 configurations obtained by docking method, the lowest binding affinity ΔEbind achieved in the best docking mode was chosen as a scoring function for picking out top ligands. For inhibition the CD44 target, the top-leads compounds with binding energy less than -9.0 kcal.mol-1 and F-19848A have selected. By docking method, the binding site and other quantities were determined such as the number of hydrogen bonds (HB), non-bond contacts (NBC) of top ligands with CD44 target. Besides, the results also showed that the non-bonded contacts dominate over hydrogen bonds in the interaction between top ligands with CD44 target.

Tackling suppressive cancer microenvironment by NARF-derived immune modulatory vaccine and its validation using simulation strategies

Introduction: Targeting tumor microenvironment is beneficial and present an ideal setting for the development of futuristic immunotherapy. Here, we make use of Nuclear prelamin A recognition factor (NARF), a protein linked to the coactivation of transcriptional regulators in human breast cancer stem cells (CSC) in our investigation.Methods: In this study, we initially computed the epitope regions possessing the ability to stimulate both T and B cells within the NARF protein. These identified epitope areas were fused with an adjuvant such as RpfB and RpfE as well as linkers like AAY, GPGPG, KK, and EAAAK. The constructed vaccine was further characterized by assessing its physicochemical properties and population coverage. The potential interactions of the designed vaccine with different toll-like receptors were examined by a sequence of computational studies. Of note, docking study were employed to understand its mechanism of action. Molecular dynamics and immune simulation studies were conducted to comprehend more into their structural stability and immune responses. The resultant vaccine was back-translated, codon-optimised and introduced into pET-28 (+) vector.Results and discussion: We hypothesize from the results that the designed NARF protein-based vaccine in our analysis could effectively provoke the immune responses in the target organism through TLR-7 binding and promotes MHC class-II mediated antigen presentation. Indeed, comprehensive evaluations conducted in both in vitro and in vivo settings are imperative to substantiate the safety and efficacy of the developed vaccine.

Central Role of β-1,4-GalT-V in Cancer Signaling, Inflammation, and Other Disease-Centric Pathways.

UDP-Galactose: Glucosylceramide, β-1,4-Galactose transferase-V (β-1,4-GalT-V), is a member of a large glycosyltransferase family, primarily involved in the transfer of sugar residues from nucleotide sugars, such as galactose, glucose mannose, etc., to sugar constituents of glycosphingolipids and glycoproteins. For example, UDP-Galactose: Glucosylceramide, β-1,4-galactosyltransferase (β-1,4-GalT-V), transfers galactose to glucosylceramide to generate Lactosylceramide (LacCer), a bioactive "lipid second messenger" that can activate nicotinamide adenine dinucleotide phosphate(NADPH) oxidase (NOX-1) to produce superoxide's (O2-) to activate several signaling pathways critical in regulating multiple phenotypes implicated in health and diseases. LacCer can also activate cytosolic phospholipase A-2 to produce eicosanoids and prostaglandins to induce inflammatory pathways. However, the lack of regulation of β-1,4-GalT-V contributes to critical phenotypes central to cancer and cardiovascular diseases, e.g., cell proliferation, migration, angiogenesis, phagocytosis, and apoptosis. Additionally, inflammation that accompanies β-1,4-GalT-V dysregulation accelerates the initiation and progression of cancer, cardiovascular diseases, as well as inflammation-centric diseases, like lupus erythematosus, chronic obstructive pulmonary disease (COPD), and inflammatory bowel diseases. An exciting development in this field of research arrived due to the recognition that the activation of β-1,4-GalT-V is a "pivotal" point of convergence for multiple signaling pathways initiated by physiologically relevant molecules, e.g., growth factors, oxidized-low density lipoprotein(ox- LDL), pro-inflammatory molecules, oxidative and sheer stress, diet, and cigarette smoking. Thus, dysregulation of these pathways may well contribute to cancer, heart disease, skin diseases, and several inflammation-centric diseases in experimental animal models of human diseases and in humans. These observations have been described under post-transcriptional modifications of β-1,4- GalT-V. On the other hand, we also point to the important role of β-1-4 GalT-V-mediated glycosylation in altering the formation of glycosylated precursor forms of proteins and their activation, e.g., β-1 integrin, wingless-related integration site (Wnt)/-β catenin, Frizzled-1, and Notch1. Such alterations in glycosylation may influence cell differentiation, angiogenesis, diminished basement membrane architecture, tissue remodeling, infiltrative growth, and metastasis in human colorectal cancers and breast cancer stem cells. We also discuss Online Mendelian Inheritance in Man (OMIM), which is a comprehensive database of human genes and genetic disorders used to provide information on the genetic basis of inherited diseases and traits and information about the molecular pathways and biological processes that underlie human physiology. We describe cancer genes interacting with the β-1,4-GalT-V gene and homologs generated by OMIM. In sum, we propose that β-1,4-GalT-V gene/protein serves as a "gateway" regulating several signal transduction pathways in oxidative stress and inflammation leading to cancer and other diseases, thus rationalizing further studies to better understand the genetic regulation and interaction of β-1,4-GalT-V with other genes. Novel therapies will hinge on biochemical analysis and characterization of β-1,4-GalT-V in patient-derived materials and animal models. And using β-1,4-GalT-V as a "bonafide drug target" to mitigate these diseases.

Effects of Combined Exposure to Carbon Ions and Protons on the Pool of MCF-7 Breast Cancer Stem Cells In Vitro.

We studied the effects of single and combined action of protons and carbon ions 12C6+ on the pool of MCF-7 human breast cancer stem cells. Single irradiation with a beam of protons or carbon ions had no significant effects on the relative number of cancer stem cells (CSC). The effects of combined irradiation in a total equieffective dose of 4 Gy depended on the sequence of exposure to ionizing radiations: the relative number of CSC did not change after irradiation with carbon ions and then with protons, but increased in the case of the reverse sequence. The most favorable result, i.e. a decrease in the CSC pool, was observed in the case of sequential irradiation with carbon ions and protons and their equal contribution to total equieffective dose. In this case, the absolute number of CSC decreased by on average 2.1 times in comparison with the control (p<0.05). The revealed regularities are of interest for the further development of new methods of radiation therapy.

Andrographolide Reverses Doxorubicin Resistance in Human Breast Cancer Stem Cells by Regulating Apoptotic Gene Expressions

BACKGROUND: Breast cancer stem cells (BCSCs) have been identified as playing a crucial role in therapeutic resistance. This resistance can be attributed to the anti-apoptotic protein survivin and the antioxidant MnSOD high expression. To overcome the resistance to doxorubicin (DOX), this study proposed the utilization of andrographolide (ANDRO), the primary bioactive compound in Andrographis paniculata leaves. The objective was to examine the role of andrographolide in regulating survivin, caspase-9, and caspase-3 gene expressions to reverse doxorubicin resistance in human BCSCs.METHODS: BCSCs were exposed to 0.1 µM DOX every two days or 50 µM rotenone (ROT) for 6 hours, subsequently supplemented with 0.3 mM ANDRO. Superoxide and peroxide levels were measured using DHE and DCFH-DA assay. The MnSOD, survivin, caspase-9, and caspase-3 mRNA expression levels were analyzed using qRT-PCR. Protein expressions were evaluated using Western blotting assay. MnSOD activity was determined using xanthine oxidase inhibition assay. The apoptotic cells were determined using Annexin-V/PI staining.RESULTS: This study indicated that the cytotoxic mechanisms of DOX, similar to ROT, in BCSCs were attributed to oxidative stress, as evidenced by an elevation in superoxide rather than peroxide levels, accompanied by a decrease in MnSOD activity. This study also highlighted that ANDRO reversed DOX resistance in BCSCs subjected to repeated DOX treatment by downregulating survivin and upregulating caspase-9 and caspase-3 mRNA expressions, thereby activating the intrinsic apoptotic pathway.CONCLUSION: This study provides insights into the role of ANDRO in modulating the expression of apoptotic genes, such as survivin, caspase-9, and caspase-3, to overcome DOX resistance in BCSCs.KEYWORDS: breast cancer, breast cancer stem cell, andrographolide, doxorubicin, oxidative stress, apoptosis

Soloxolone methyl induces apoptosis and oxidative/ER stress in breast cancer cells and target cancer stem cell population.

One of the most prevalent malignancies in women and one of the leading causes of cancer-related death is breast cancer. There is a need for new treatment approaches and drugs for breast cancer. Many studies show the high potential of triterpene compounds and their semisynthetic derivatives as anticancer agents due to their ability to induce apoptosis and suppress tumorigenesis. The effects of soloxolone methyl (SM), a semisynthetic derivative of 18-H-glycyrrhetinic acid, on the cytotoxicity and apoptosis of human breast cancer cell line (T-47D) and cancer stem cell (CSCs) population (mammospheres; CD44+/CD24-antigen) derived from breast cancer cells, were examined in this work. The ATP assay was used to determine SM growth-inhibitory effects. Fluorescent staining, caspase-cleaved cytokeratin 18, and flow cytometry analysis were used to determine the mode of the cell death. In addition, cell death was investigated at protein and gene levels by Western Blotting and PCR, respectively. SM resulted in cytotoxicity in a time and dose dependent manner via ROS production and ER stress in T-47D cells in 2 models. The mode of cell death was apoptosis, evidenced by phosphatidylserine exposure, caspase activation, and bax overexpression. In mammospheres as 3D model, SM decreased stem cell properties and induced cell death. Taken together, SM may be a promising agent in the treatment of breast cancer, especially due to its antigrowth activity on CSCs.

Expression of Nuclear Factor – kappa B (NF-kB) in Human Breast Cancer Stem Cells (CD 24-/CD 44+) Treated with H2O2 and Its Relationship with Cell Viability

Introduction: Breast cancer is one of the highest causes of death from cancer in women in Indonesia. This is partly due to the resistance of ROS-based therapies such as radiotherapy and chemotherapy. Breast cancer stem cells (cancer stem cells, CSCs) have a role in this resistance mechanism. Previous studies demonstrated the ability of CSC to survive oxidative stress conditions due to rotenone administration. Therefore, in this study an analysis was carried out on the transcription factor NF-kB in breast cancer cells, both CSCs and Non CSCs, related to the role of NF-kB in maintaining the survival of cancer cells under conditions of oxidative stress. Methods: The study was conducted on human breast cancer stem cells (CD24-/CD44+) and non stem cells (CD24-/CD44-) which were given H2O2 at concentrations of 1.1µM, 11µM, and 110µM with control cells not given H2O2. Assessment was carried out on the parameters of NF-kB mRNA expression, and cell viability. Results: Administration of H2O2 at a concentration of 11µM showed a significant increase in the expression of NFk-B CSCs mRNA compared to non CSCs (p&lt;0.05). As for the viability test results, at all concentrations of H2O2 it appears that CSCs was able to maintain its viability compared to non CSCs which experienced a decrease in viability (p&lt;0.05). Conclusion: In this study, conditions of oxidative stress due to the administration of H2O2 led to an increase in the expression of NF-kB mRNA in CSCs so that cell viability could be maintained.

Vandetanib alters the tumoricidal capacity of human breast cancer stem cells via inhibiting vasculogenic capacity.

The inhibition of vascularization into tumor stroma as well as dynamic cell growth is the center of attention. Here, we aimed to examine the role of vandetanib on angiogenesis capacity of breast cancer stem cell (CSCs). MDA-MB-231 cells were exposed to different doses of vandetanib and survival rate was monitored. Stimulatory effects of vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF), and epidermal growth factor (EGF) were evaluated in vandetanib-treated MDA-MB-231 cells. In vitro tubulogenesis capacity was studied on the Matrigel surface. The synergistic effects of vandetanib on cell survival were also assessed after PI3K and/or Wnt3a inhibition. Vascular endothelial (VE)-cadherin, matrix metalloproteinase-2 (MMP-2), -9, Wnt3a, and p-Akt/Akt ratio were measured using western blotting. Vandetanib reduced survival rate in a dose-dependent manner (P<0.05). Proliferative effects associated with VEGF, FGF, and EGF were blunted in these cells pre-exposed to vandetanib (P<0.05). The microcirculation pattern's triple-negative breast cancer (TNBC) was suppressed by 1, 5 µM of vandetanib (P<0.05). Hence 1, 5 µM of vandetanib potentially decreased the population of CD24- cells. 1 and 5 µM of vandetanib inhibited cell proliferation by blocking PI3K and Wnt3a pathways and decreased the p-Akt/Akt ratio, Wnta3 protein levels (P<0.05). 1 and 5 µM vandetanib combined with PI3K inhibitor diminished metastatic markers including, MMP-2, and MMP-9. The concurrent treatment (PI3K, inhibitor+ 1, 5 µM vandetanib) also considerably reduced epithelial-mesenchymal transition (EMT) markers such as VE-cadherin (P<0.05). Vandetanib suppressed vasculogenic mimicry (VM) networking through blunting stemness properties, coincided with suppression of VE-cadherin in CSCs.

Bilateral Feedback in Oscillator Model Is Required to Explain the Coupling Dynamics of Hes1 with the Cell Cycle

Biological processes are governed by the expression of proteins, and for some proteins, their level of expression can fluctuate periodically over time (i.e., they oscillate). Many oscillatory proteins (e.g., cell cycle proteins and those from the HES family of transcription factors) are connected in complex ways, often within large networks. This complexity can be elucidated by developing intuitive mathematical models that describe the underlying critical aspects of the relationships between these processes. Here, we provide a mathematical explanation of a recently discovered biological phenomenon: the phasic position of the gene Hes1’s oscillatory expression at the beginning of the cell cycle of an individual human breast cancer stem cell can have a predictive value on how long that cell will take to complete a cell cycle. We use a two-component model of coupled oscillators to represent Hes1 and the cell cycle in the same cell with minimal assumptions. Inputting only the initial phase angles, we show that this model is capable of predicting the dynamic mitosis to mitosis behaviour of Hes1 and predicting cell cycle length patterns as found in real-world experimental data. Moreover, we discover that bidirectional coupling between Hes1 and the cell cycle is critical within the system for the data to be reproduced and that nonfixed asymmetry in the interactions between the oscillators is required. The phase dynamics we present here capture the complex interplay between Hes1 and the cell cycle, helping to explain nongenetic cell cycle variability, which has critical implications in cancer treatment contexts.

Impairment of Glucose Metabolism and Suppression of Stemness in MCF-7/SC Human Breast Cancer Stem Cells by Nootkatone.

Targeting cancer stem cell metabolism has emerged as a promising therapeutic strategy for cancer treatment. Breast cancer stem cells (BCSCs) exert distinct metabolism machinery, which plays a major role in radiation and multidrug resistance. Therefore, exploring the mechanisms involved in energy utilization of BCSCs could improve the effectiveness of therapeutic strategies aimed at their elimination. This study was conducted to clarify the glucose metabolism machinery and the function of nootkatone, a bioactive component of grapefruit, in regulating glucose metabolism and stemness characteristics in human breast carcinoma MCF-7 stem cells (MCF-7SCs). In vivo experiments, transcriptomic analysis, seahorse XF analysis, MTT assay, Western blotting, mammosphere formation, wound healing, invasion assay, flow cytometric analysis, reverse transcription-quantitative polymerase chain reaction, and in silico docking experiments were performed. MCF-7SCs showed a greater tumorigenic capacity and distinct gene profile with enrichment of the genes involved in stemness and glycolysis signaling pathways compared to parental MCF-7 cells, indicating that MCF-7SCs use glycolysis rather than oxidative phosphorylation (OXPHOS) for their energy supply. Nootkatone impaired glucose metabolism through AMPK activation and reduced the stemness characteristics of MCF-7SCs. In silico docking analysis demonstrated that nootkatone efficiently bound to the active site of AMPK. Therefore, this study indicates that regulation of glucose metabolism through AMPK activation could be an attractive target for BCSCs.

Therapeutic Effect of Anti-miRNA Mediated by RNA Nanoparticles Targeting CD133 on Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is a malignant tumor with a high mortality. Herein, anti-miRNA was investigated for TNBC treatment and explored therapeutic effect was assessed to provide a theoretical basis for treating TNBC. The thermodynamic and chemically stable 3WJ served as a scaffold to construct an RNA nucleic acid ligand that bonded to the CD133 receptor and an LNA sequence containing anti-miRNA21. The constructed nanoparticles were characterized and then applied to TNBC animal models, human breast cancer cells and stem cells (BCSCs), to explore the effect of RNA nanoparticles on TNBC. The study on CD133 aptamers mainly focused on TNBC cells and BCSCs. Results from the study showed specific uptake of nanoparticles. Functional assays showed that treatment with 3WJ/CD133apt/anti-miR21 decreased cell migration and miR21 expression, and increased the expression of PTEN and PDCD, but cytokine secretion did not affect the content of cytokine. Animal experiments proved that the RNA nanoparticles had high targeting of TNBC tumors and had a good suppressive effect on tumor growth. Nanoparticles carrying anti-miR21 could be used an effective treatment method for TNBC. The current study elucidated nanoparticles carrying anti-miR21exerted a significant therapeutic effect on TNBC, helping the development of targeted treatment of TNBC.

Glycosphingolipids in human embryonic stem cells and breast cancer stem cells, and potential cancer therapy strategies based on their structures and functions.

Expression profiles of glycosphingolipids (GSLs) in human embryonic stem cell (hESC) lines and their differentiated embryoid body (EB) outgrowth cells, consisting of three germ layers, were surveyed systematically. Several globo- and lacto-series GSLs were identified in undifferentiated hESCs and during differentiation of hESCs to EB outgrowth cells, and core structure switching of these GSLs to gangliosides was observed. Such switching was attributable to altered expression of key glycosyltransferases (GTs) in GSL biosynthetic pathways, reflecting the unique stage-specific transitions and mechanisms characteristic of the differentiation process. Lineage-specific differentiation of hESCs was associated with further GSL alterations. During differentiation of undifferentiated hESCs to neural progenitor cells, core structure switching from globo- and lacto-series to primarily gangliosides (particularly GD3) was again observed. During differentiation to endodermal cells, alterations of GSL profiles were distinct from those in differentiation to EB outgrowth or neural progenitor cells, with high expression of Gb4Cer and low expression of stage-specific embryonic antigen (SSEA)-3, -4, or GD3 in endodermal cells. Again, such profile changes resulted from alterations of key GTs in GSL biosynthetic pathways. Novel glycan structures identified on hESCs and their differentiated counterparts presumably play functional roles in hESCs and related cancer or cancer stem cells, and will be useful as surface biomarkers. We also examined GSL expression profiles in breast cancer stem cells (CSCs), using a model of epithelial-mesenchymal transition (EMT)-induced human breast CSCs. We found that GD2 and GD3, together with their common upstream GTs, GD3 synthase (GD3S) and GD2/GM2 synthase, maintained stem cell phenotype in breast CSCs. Subsequent studies showed that GD3 was associated with epidermal growth factor receptor (EGFR), and activated EGFR signaling in breast CSCs and breast cancer cell lines. GD3S knockdown enhanced cytotoxicity of gefitinib (an EGFR kinase inhibitor) in resistant MDA-MB468 cells, both in vitro and in vivo. Our findings indicate that GD3S contributes to gefitinib resistance in EGFR-positive breast cancer cells, and is a potentially useful therapeutic target in drug-resistant breast cancers.

Effect of Cell Culture Medium on the Proliferation and Stemness of CD24-/CD44+ Human Breast Cancer Stem Cells

BACKGROUND: Cancer stem cells (CSCs) is defined as tumor initiating cells within tumor that maintain stemness properties and tumorigenicity. Extracellular pH of CSCs in in vitro condition is important for supporting cell proliferation which may also regulate the expression of stemness markers such as OCT4. This work aimed to examine the effect of cell culture media on the proliferation and stemness of human breast cancer stem cells (BCSCs).METHODS: Human CD24-/CD44+ BCSCs were grown in Dulbecco's Modified Eagle Medium/F-12 (DMEM/F-12) with 15mM 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES), without HEPES and adjusted to pH 7.4, or without HEPES but pH was not adjusted. BCSCs were grown under standard conditions for various days. Viable cell number was measured using trypan blue exclusion, whereas proliferation rate using MTS assay. OCT4 mRNA and protein were analyzed using quantitative real time PCR (qRT-PCR) and Western Blot assay, respectively. In vitro tumorigenic activity was determined using mammosphere formation unit (MFU) assay.RESULTS: Our results showed a higher viable cell number and proliferation of BCSCs in DMEM/F-12 HEPES (-) compared to HEPES (+) medium until 4 day incubation. OCT4 mRNA and protein level, as well as MFU of BCSCs were significantly higher in HEPES (-) compared to HEPES (+) medium on day 2.CONCLUSION: DMEM/F-12 medium without HEPES facilitates CD24-/CD44+ BCSCs to have higher proliferation and stemness on day 2 incubation compared to those with HEPES.KEYWORDS: breast cancer, cancer stem cell, OCT4, stemness, proliferation

Thymoquinone inhibited vasculogenic capacity and promoted mesenchymal-epithelial transition of human breast cancer stem cells

BackgroundVasculogenic mimicry (VM) is characterized by the formation of tubular structure inside the tumor stroma. It has been shown that a small fraction of cancer cells, namely cancer stem cells (CSCs), could stimulate the development of vascular units in the tumor niche, leading to enhanced metastasis to the remote sites. This study aimed to study the inhibitory effect of phytocompound, Thymoquinone (TQ), on human breast MDA-MB-231 cell line via monitoring Wnt/PI3K signaling pathway.MethodsMDA-MB-231 CSCs were incubated with different concentrations of TQ for 48 h. The viability of CSCs was determined using the MTT assay. The combination of TQ and PI3K and Wnt3a inhibitors was examined in CSCs. By using the Matrigel assay, we measured the tubulogenesis capacity. The percent of CD24− CSCs and Rhodamine 123 efflux capacity was studied using flow cytometry analysis. Protein levels of Akt, p-Akt, Wnt3a, vascular endothelial-cadherin (VE-cadherin), and matrix metalloproteinases-2 and -9 (MMP-2 and -9) were detected by western blotting.ResultsTQ decreased the viability of CSCs in a dose-dependent manner. The combination of TQ with PI3K and Wnt3a inhibitors reduced significantly the survival rate compared to the control group (p < 0.05). TQ could blunt the stimulatory effect of vascular endothelial growth factor (VEGF), epidermal growth factor (EGF), fibroblast growth factor (FGF) on CSCs (p < 0.05). The vasculogenic capacity of CSCs was reduced after being-exposed to TQ (p < 0.05). Western blotting revealed the decrease of CSCs metastasis by suppressing MMP-2 and -9. The protein level of VE-cadherin was also diminished in TQ-treated CSCs as compared to the control cell (p < 0.05), indicating inhibition of mesenchymal-endothelial transition (MendT). TQ could suppress Wnt3a and PI3K, which coincided with the reduction of the p-Akt/Akt ratio. TQ had the potential to decrease the number of CD24− CSCs and Rhodamine 123 efflux capacity after 48 h.ConclusionTQ could alter the vasculogenic capacity and mesenchymal-epithelial transition of human breast CSCs in vitro. Thus TQ together with anti-angiogenic therapies may be a novel therapeutic agent in the suppression of VM in breast cancer.

Human Primary Breast Cancer Stem Cells Are Characterized by Epithelial-Mesenchymal Plasticity.

Triple-negative breast cancer (TNBC) is one of the most aggressive subtypes of breast cancer, with only limited treatment options available. Recently, cancer stem cells (CSCs) have emerged as the potential drivers of tumor progression due to their ability to both self-renew and give rise to differentiated progeny. The CSC state has been linked to the process of epithelial-mesenchymal transition (EMT) and to the highly flexible state of epithelial-mesenchymal plasticity (EMP). We aimed to establish primary breast cancer stem cell (BCSC) cultures isolated from TNBC specimens. These cells grow as tumor spheres under anchorage-independent culture conditions in vitro and reliably form tumors in mice when transplanted in limiting dilutions in vivo. The BCSC xenograft tumors phenocopy the original patient tumor in architecture and gene expression. Analysis of an EMT-related marker profile revealed the concomitant expression of epithelial and mesenchymal markers suggesting an EMP state for BCSCs of TNBC. Furthermore, BCSCs were susceptible to stimulation with the EMT inducer TGF-β1, resulting in upregulation of mesenchymal genes and enhanced migratory abilities. Overall, primary BCSC cultures are a promising model close to the patient that can be used both in vitro and in vivo to address questions of BCSC biology and evaluate new treatment options for TNBC.

In silico and in vitro studies on the anti-cancer activity of andrographolide targeting survivin in human breast cancer stem cells.

Breast cancer stem cells (BCSCs) express high levels of the anti-apoptotic protein, survivin. This study aimed to discover a natural active compound with anti-cancer properties that targeted survivin in human breast cancer stem cells. From the seven examined compounds, andrographolide was selected as a lead compound through in silico molecular docking with survivin, caspase-9, and caspase-3. We found that the affinity between andrographolide and survivin is higher than that with caspase-9 and caspase-3. Human CD24-/CD44+ BCSCs were treated with andrographolide in vitro for 24 hours. The cytotoxic effect of andrographolide on BCSCs was compared to that on human mesenchymal stem cells (MSCs). The expression of survivin, caspase-9, and caspase-3 mRNA was analyzed using qRT-PCR, while Thr34-phosphorylated survivin and total survivin levels were determined using ELISA and Immunoblotting assay. Annexin-V/PI flow cytometry assays were performed to evaluate the apoptotic activity of andrographolide. Our results demonstrate that the CC50 of andrographolide in BCSCs was 0.32mM, whereas there was no cytotoxic effect in MSCs. Moreover, andrographolide decreased survivin and Thr34-phosphorylated survivin, thus inhibiting survivin activation and increasing survivin mRNA in BCSCs. The apoptotic activity of andrographolide was revealed by the increase of caspase-3 mRNA and protein, as well as the increase in both the early and late phases of apoptosis. In conclusion, andrographolide can be considered an anti-cancer compound that targets BCSCs due to its molecular interactions with survivin, caspase-9, and caspase-3, which induce apoptosis. We suggest that the binding of andrographolide to survivin is a critical aspect of the effect of andrographolide.

Effects of Quinacrine on Expression of Hippo signaling Pathway Components (LATS1, LATS2, and YAP) in Human Breast Cancer Stem Cells.

Objective:The Hippo signaling pathway has important role in the pathogenesis of some tumors. Breast cancer is the most prevalent cancer among females in the world. In recent years, various articles referred to inhibiting effect of quinacrine, a derivative of 9-aminoacridine, on the growth of several types of cancer cells. In this study, we evaluated the effect of quinacrine on expression of LATS1, LATS2, and YAP genes of the Hippo signaling pathway and YAP level in human breast cancer stem cells (MDA-MB 231 cell line). This cell line of breast cancer expresses the triple negative characteristics. Methods:MDA-MB 231 cells was treated with 0.5 µM of quinacrine for 3 days. The dose was selected using MTT assays. The expression of genes was quantified by Real-time PCR. The protein expression was performed by Western blotting. Significance of observations were checked by means of Mann-Whitney test using p<0.05 as the level of significance. Results:The present study demonstrated that expression of YAP gene in MDA-MB 231 cell line significantly down regulated by quinacrine. Quinacrine significantly decreased the amount of YAP protein. Moreover, quinacrine did not have meaningful effect on LATS1 and LATS2 genes expression. Conclusion: YAP gene is an oncogene and inhibition of its expression by quinacrine could effect on breast cancer cell progression.

Isolation and Functional Assessment of Human Breast Cancer Stem Cells from Cell and Tissue Samples.

Breast cancer stem cells (BCSCs) are cancer cells with inherited or acquired stem cell-like characteristics. Despite their low frequency, they are major contributors to breast cancer initiation, relapse, metastasis and therapy resistance. It is imperative to understand the biology of breast cancer stem cells in order to identify novel therapeutic targets to treat breast cancer. Breast cancer stem cells are isolated and characterized based on expression of unique cell surface markers such as CD44, CD24 and enzymatic activity of aldehyde dehydrogenase (ALDH). These ALDHhighCD44+CD24- cells constitute the BCSC population and can be isolated by fluorescence-activated cell sorting (FACS) for downstream functional studies. Depending on the scientific question, different in vitro and in vivo methods can be used to assess the functional characteristics of BCSCs. Here, we provide a detailed experimental protocol for isolation of human BCSCs from both heterogenous populations of breast cancer cells as well as primary tumor tissue obtained from breast cancer patients. In addition, we highlight downstream in vitro and in vivo functional assays including colony forming assays, mammosphere assays, 3D culture models and tumor xenograft assays that can be used to assess BCSC function.

Isolation and Functional Assessment of Human Breast Cancer Stem Cells from Cell and Tissue Samples

Isolation and Functional Assessment of Human Breast Cancer Stem Cells from Cell and Tissue Samples

Suppression of Rotenone-Treated Human Breast Cancer Stem Cell Survival Using Survivin Inhibitor YM155 is Associated to Oxidative Stress Modulation.

Background:Despite recent progress in molecular-targeted therapies, breast cancer remains the primary leading cause of cancer related death among women worldwide. Breast cancer stem cells (BCSCs) are believed to be responsible for therapy resistance and cancer recurrence. We recently demonstrated that human BCSCs (CD24-/CD44+) could survive better than their counterpart non-BCSCs (CD24-/CD44-) when treated with rotenone, possibly due to lower levels of reactive oxygen species (ROS) production, high expression of antioxidant manganese superoxide dismutase (MnSOD), and anti-apoptotic survivin. The aim of this study was to verify the role of survivin on human BCSCs survival under oxidative stress modulation by suppressing its expression using YM155, a survivin inhibitor. Methods:Human BCSCs (ALDH+ cells) were treated with YM155 for 24 h prior to treatment with rotenone for a further 6 h. We determined intracellular superoxide levels were determined using dihydroethidium assay, survivin and MnSOD expression using qRT-PCR, survivin protein level using ELISA, as well as cell viability using trypan blue exclusion and acridine orange/ethidium bromide apoptosis assay. Results:Suppression of survivin expression using YM155 could reduce the survival of rotenone-treated BCSCs, which may be associated with oxidative stress modulation, as shown by increased ROS levels and decreased MnSOD expression. We confirm that survivin is responsible for maintaining BCSCs survival under oxidative stress modulation. Furthermore, YM155 could modulate oxidative stress in BCSCs by reducing MnSOD expression and increasing ROS levels. Conclusion:YM155 treatment could be used to overcome BCSCs resistance to oxidative stress-based anticancer therapies.