UBE2T mediates the stemness properties of breast cancer cells through the mTOR signaling pathway

Objectives:This study aimed to reveal the role and possible mechanism of the ubiquitin-conjugating enzyme 2T(UBE2T)in the biological activities of breast cancer stem cells(BCSCs).Methods:The specific protein and gene expression were quantified by Western blotting and quantitative real-time polymerase chain reaction,the proportion of BCSCs was examined by flow cytometry,and the self-renewal and proliferation of BCSCs were verified by serial sphere formation and soft agar.Results:Increasing expression of UBE2T was drastically found in breast cancer than that in adjacent tissues.Furthermore,UBE2T overexpression significantly increased the proportion of BCSCs in breast cancer cells and promoted their self-renewal and proliferation.Silent UBE2T exhibited the opposite functions.UBE2T increased the levels of the mammalian target of rapamycin and the phosphorylated mammalian target of rapamycin.Mammalian target of rapamycin(mTOR)inhibitor rapamycin inhibited the function of UBE2T in BCSCs.Conclusion:UBE2T plays a role in BCSCs through mTOR pathway and may suggest a novel therapeutic strategy for breast cancer.

IN SITU IMAGING OF BREAST CANCER CELLS USING GREEN SEMICONDUCTOR QUANTUM DOTS

The breast cancer is the most common cause of cancer death in women. To establish an early stage in situ imaging of breast cancer cells, green quantum dots （QDs） are used as a fluorescent signal generator. The QDs based imaging of breast cancer cells involves anti-HER2/neu antibody for labeling the over expressed HER2 on the surface of breast cancer cells. The complete assay involves breast cancer cells, biotin labeled antibody and streptavidin conjugated QDs. The breast cancer cells are grown in culture plates and exposed to the biotin labeled antibodies, and then exposed to streptavidin labeled QDs to utilize the strong and stable biotin-streptavidin interaction. Fluorescent images of the complete assay for breast cancer cells are evaluated on a microscope with a UV light source. Results show that the breast cancer cells in the complete assay are used as fluorescent cells with brighter signals compared with those labeled by the organic dye using similar parameters and the same number of cells.

Piperine suppresses growth and migration of human breast cancer cells through attenuation of Rac1 expression

Objective:To investigate the effect of piperine on human breast cancer cells.Methods:The effect of piperine on proliferation and migration of human breast cancer cells,MCF-7 and MDA-MB-231,was investigated using colony formation assays,wound healing assays,Matrigel migration assays,flow cytometry,RT-qPCR,and Western blotting assays.Results:Piperine inhibited the growth of MCF-7 and MDA-MB-231 cells and suppressed colony formation.Cell reduction at the G_(0)/G_(1) phase and cell arrest at the G_(2)/M phase were observed in breast cancer cells.However,the significant effect was only demonstrated in MDA-MB-231 cells.Moreover,cancer cell migration was suppressed by piperine at low concentration.RT-qPCR and Western blotting assays showed that piperine downregulated Rac1 gene and protein expression.Conclusions:Piperine could inhibit growth and migration of breast cancer cells by reducing Rac1 gene and protein expression.

Effects of bisphenol compounds on the growth and epithelial mesenchymal transition of MCF-7 CV human breast cancer cells

Bisphenol-A（BPA） has been considered as an endocrine disrupting chemical（EDC） because it can exert estrogenic properties.For bisphenol-S（BPS） and bisphenol-F（BPF） that are BPA analogs and substitutes,their risk to estrogendependent cancer has been reported rarely compared with the numerous cases of BPA.In this study,we examined whether BPA,BPS,and BPF can lead to the proliferation,migration,and epithelial mesenchymal transition（EMT） of MCF-7 clonal variant（MCF-7 CV） breast cancer cells expressing estrogen receptors（ERs）.In a cell viability assay,BPA,BPS,and BPF significantly increased proliferation of MCF-7 CV cells compared to control（DMSO） as did17β-estradiol（E2）.In Western blotting assay,BPA,BPS,and BPF enhanced the protein expression of cell cycle progression genes such as cyclin D1 and E1.In addition,MCF-7 CV cells lost cell to cell contacts and acquired fibroblast-like morphology by the treatment of BPA,BPS,or BPF for 24 hours.In cell migration assay,BPA,BPS,and BPF accelerated the migration capability of MCF-7 CV cells as did E2.In relation with the EMT process,BPA,BPS,and BPF increased the protein expression of N-cadherin,while they decreased the protein expression of Ecadherin.When BPA,BPS,and BPF were co-treated with ICI 182,780,an ER antagonist,proliferation effects were reversed,the expression of cyclin D1 and cyclin E1 was downregulated,and the altered cell migration and expression of N-cadherin and E-cadherin by BPA,BPS,and BPF were restored to the control level.Thus,these results imply that BPS and BPF also have the risk of breast cancer progression as much as BPA in the induction of proliferation and migration of MCF-7 CV cells by regulating the protein expression of cell cycle-related genes and EMT markers via the ER-dependent pathway.

Cu(II) Benzoylpyridine Thiosemicarbazone Complexes: Inhibition of Human Topoisomerase IIα and Activity against Breast Cancer Cells

The focus of this research is on the study of a series of copper (II) benzoylpyridine thiosemicarbazone complexes. Of the six benzoylpyridine thiosemicarbazone ligands used in this study, two are reported for the first time;2-benzoylpyridine tert-butyl thiosemicarbazone (BZP-tBTSC), and 2-benzoylpyridine benzyl thiosemicarbazone (BZP-BzTSC). Once characterized by NMR, melting point, and MS, these mono-anionic tridentate ligands were then reacted with Cu2+ to form the new square planar metal complexes [Cu(BZP-tBTSC)Cl] and [Cu(BZP-BzTSC)Cl]. All of the copper complexes display marked inhibition of human topoisomerase IIα. The [Cu(BZP-tBTSC)Cl] complex shows marked activity against human breast cancer cell lines.

QCM Detection of Adhesion, Spreading and Proliferation of Human Breast Cancer Cells (MCF-7) on a Gold Surface

The quartz crystal microbalance （QCM） was used to monitor the one-day incubation of human breast cancer cells （MCF-7） on the gold electrode. In combination with an optical microscope simulation experiment, the cell-population pictures at various stages, the QCM responses to the cells＇ adhesion, spreading and proliferation on the electrode surface were discussed. The △f0 and △R1 responses were found mainly from mixed effects of viscodensity and surface stress, and in proportion to the cell coverage, rather than to the number of cells at the electrode. The significant fore-and-aft changes in cyclic voltammetry and electrochemical impedance spectroscopy of the ferri-ferrocyanide redox couple also proved that the cells were adhesion to the gold surface.

Investigating the effects of Pentoxifylline on human breast cancer cells using Raman spectroscopy

Breast cancer is one of the leading causes of cancer-related deaths in a global scenario.In the present study,biochemical changes exerted upon Pentoxifylline(PTX)treatment had been ap-praised in human breast cancer cells using Raman spectrosecopy.There are no clinically approved methods to monitor such therapeutic responses available.The spectral profiling is suggestive of changes in DNA,protein and lipid contents showing a linear relationship with drug dosage.Further,multivariate analysis using principal component based linear-discriminant-analysis(PC-LDA)was employed for dlassifying the control and the PTX treated groups.These findings support the feasibility of Raman spectroscopy as an alternate/adjunct label-free,objective method for monitoring drug-induced modifications against breast cancer cells.

Effect of Estrogen on Telomerase Activity in Human Breast Cancer Cells

To investigate the effects of estrogen(E 2) on telomerase activity and its mechanism in human breast cancer cells, estrogen receptor positive MCF-7 cells were treated with different concentrations of E 2 Telomerase activity was measured by using TRAP-ELISA method, the cell cycle phases analyzed by using flow cytometry, and the expression of Cyclin D 1 detected by using immunohistochemistry method The results showed that telomerase activity levels were increased in MCF-7 cells treated with 10 -8 mol/L E 2 during the observed period ( P <0 05), and E 2 increased telomerase activity levels in a dose-dependent manner(10 -10 -10 -8 mol/L); Simultaneously, the cell cycle phases of MCF-7 cells treated with 10 -8 mol/L E 2 were changed significantly: G 0/G 1 phase decreased from 60 52% to 50 93%, S phase increased from 29 03% to 30 83%; However, the expression of Cyclin D 1 was decreased It was concluded that estrogen can upregulate telomerase activity of MCF-7 cells, and the effect can be blocked by antiestrogen tamoxifen Its mechanism may be closely associated with modulation of cell cycle phases

The Influence of Phorbol Ester on the Effect of Tamoxifen in Breast Cancer Cells

To investigate the correlation between the activity of kinases in the growth factor signal transduction pathway and the development of resistance of breast cancer to tamoxifen, reporter gene regulated by the regulating fragment of CCD1 was transfected into the MCF 7 cells, and the influence of tamoxifen on the reporter gene expression was examined under different conditions of TPA treatment. Our results showed that the reporter gene expression was inhibited by tamoxifen and promoted by TPA. Furthermore, tamoxifen exerts an agonist effect on the reporter gene expression when the cells was treated by TPA previously for 12 h. It is concluded that TPA could induce estrogen like effect of tamoxifen on estrogen receptor positive breast cancer cells and it may be one of the mechanisms responsible for the development of tamoxifen resistance.

In Vivo Selection of Phage Sequences and Characterization of Peptide-specific Binding to Breast Cancer Cells

OBJECTIVE To screen specific polypeptide target binding to breast cancer xenografts in vivo from a phage-displayed peptide library in order to provide peptide sequences for breast cancer tumor-targeting diagnosis and therapy. METHODS A mouse model for carrying breast cancer xenografts was established using Tientsin Albinao Ⅱ mice （TA Ⅱ）. A 12-peptide library was biopanned through 4 rounds. Phages were recovered and titrated from tumor xenografts and control tissue （liver）. The distribution of phages was detected by immunohistochemical staining. RESULTS Phage homing to breast cancer was enriched through 4 rounds of biopanning, being 14-fold of that recovered from liver tissue. A peptide sequence, ASANPFPTKALL was characterized by randomly picked-up clones which appeared most frequently. Immunohistochemical staining revealed phage localization in cancer xenografts 40 min after injection of the enriched phages. When a specific phage was tested individually, the phage reclaimed from breast cancer xenografts was 14 times as those from control tissues. CONCLUSION Tumor-specific homing peptides may provide an effective tool for breast cancer target therapy. The in vivo phage display selection technique employed in this study was feasible and applicable to screening peptides that home to breast cells.

Inhibitory Effects of Mild Hyperthermia plus Docetaxel Therapy on ER(+/–) Breast Cancer Cells and Action Mechanisms

Summary： The purpose of this study was to verify that a combination of mild hyperthermia and do- cetaxel chemotherapy produces synergistic antitumor effects and to explore the action mechanisms of this treatment approach. The effects of docetaxel on the proliferation of cells from the estrogen receptor （ER）-positive human breast cancer cell line MCF-7 and the ER-negative human breast cancer cell line MDA-MB-453 were examined by 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide （MTT） assay, and effective experimental concentrations of docetaxel were determined. The effects of mild hy- perthermia plus docetaxel therapy on apoptosis rate in the MCF-7 and MDA-MB-453 human breast cancer cell lines were analyzed by using flow cytometry with Annexin-V fluorescein isothiocyanate （FITC）/propidium iodide （PI） staining. The effects of these combined treatments on cell cycle progres- sion in the MCF-7 and MDA-MB-453 human breast cancer cell lines were examined by using flow cy- tometry. The effects of these combined treatments on the expression of apoptosis-related proteins and proteins in the mitogen-activated protein kinase （MAPK） pathways were analyzed by using Western blotting. The effects of these combined treatments on the expression of the heat shock protein 70 （HSP70） and the multi-drug resistance （MDR） gene product P-glycoprotein （Pgp） were examined by using Western blotting. The results showed that the half-maximal inhibitory concentration （IC50） of do- cetaxel for MCF-7 and MDA-MB-453 cells was 19.57±1.12 and 21.64±2.31 gmol/L respectively. Mild hyperthermia with docetaxel therapy could increase apoptosis rate in the MCF-7 and MDA-MB-453 cells. Apoptosis rate in MCF-7 and MDA-MB-453 cells was increased from （23.66±3.59）% and （18.51±3.17）% in docetaxel treatment group to （47.12±6.73）% and （55.16±7.42）% in mild hyperthermia plus docetaxel group, indicating that the mild hyperthermia and docetaxel therapeutic approaches exhib- ited significant synergistic antitumor effects. Treatments of mild hyperthermia plus docetaxel induced G2/M cell cycle arrest in the MCF-7 and MDA-MB-453 cells. Western blotting demonstrated that pro- teins in the MAPK pathway were expressed at higher levels in docetaxel-treated cells following mild hypothermia than those in cells treated with docetaxel alone. As compared with blank control group, cells from the mild hyperthermia plus docetaxel group exhibited significantly decreased B-cell lym- phoma 2 （Bcl-2） protein expression but slightly increased Bcl-2-associated X protein （Bax） expression. Western blotting results revealed that HSP70 and Pgp expression levels were significantly increased following mild hypothermia. It was concluded that treatments of mild hyperthermia plus docetaxel in- hibited the proliferation of human breast cancer cells, promoted apoptosis of breast cancer cells, and produced synergistic antitumor effects.

Activation of Rac1-PI3K/Akt is required for epidermal growth factorinduced PAK1 activation and cell migration in MDA-MB-231 breast cancer cells

Epidermal growth factor （EGF） may increase cell motility, an event implicated in cancer cell invasion and metastasis. However, the underlying mechanisms for EGF-induced cell motility remain elusive. In this study, we found that EGF treatment could activate Ras-related C3 botulinum toxin substrate 1 （Racl）, PI3K/Akt and p21- actived kinase （PAK1） along with cell migration. Ectopic expression of PAK1 K299R, a dominant negative PAK1 mutant, could largely abolish EGF-induced cell migration. Blocking PI3K/Akt signalling with LY294002 or Akt siRNA remarkably inhibited both EGF-induced PAK1 activation and cell migration. Furthermore, expression of dominant-negative Racl （T17N） could largely block EGF-induced PI3K/Akt-PAK1 activation and cell migration. Interestingly, EGF could induce a significant production of ROS, and N-acetyl-L-cysteine, a scavenger of ROS which abolished the EGF-induced ROS generation, cell migration, as well as activation of PI3K/Akt and PAK, but not Racl. Our study demonstrated that EGF-induced cell migration involves a cascade of signalling events, including activation of Racl, generation of ROS and subsequent activation of PI3K/Akt and PAK1.

Cyclin E Expression and Chemotherapeutic Sensitivity in Breast Cancer Cells

The effects of the cyclin E expression levels on chemotherapeutic sensitivity of breast cancer cell line were explored. After the cyclin E expression was knockdown in MDA-MB-435 by RNA interference, FACS analysis and SA-β-gal staining were used to evaluate the response sensitivity of breast cancer cells to DNA damage drugs （adriamycin, etc.）. Adriamycin could induce G1 arrest in cyclin E knockdown MDA-MB-435 breast cell line and increase the percentage of cell senescence in cyclin E knockdown MDA-MB-435 cells. It was suggested that cyclin E knockdown could increase the chemotherapeutic sensitivity of breast cancer cells to DNA damage drugs.

Research Progress of Breast Cancer Stem Cell Stemness and Breast Cancer Recurrence

Currently, breast cancer is the most common malignant tumour in Chinese women with a high incidence rate, and recurrence and metastasis are the main reasons affecting survival. Breast Cancer Stem Cells (BCSCs) are stem cells capable of continuous regeneration in vivo with strong self-renewal ability and multidirectional differentiation potential, which are highly tumourigenic and insensitive to radiotherapy and chemotherapy, and are highly susceptible to breast cancer recurrence. Therefore, exploring the stemness of BCSCs and their mechanism associated with recurrence is important for developing new therapeutic strategies, improving therapeutic efficacy, and improving patient prognosis.

Retroviral vector containing human p16 gene and its inhibitory effect on Bcap-37 breast cancer cells

Objective To study the effects of the p16 gene on tumor cell growth inhibition and cell cycle arrest. Methods The recombinant retroviral vector pLp16SN was constructed by cloning the human p16 cDNA into the retroviral vector pLXSN. Retroviruses with or without the p16 gene were obtained by transfecting pLp16SN and pLXSN vectors into PA317 cells. Bcap-37 human breast cancer cells were infected with these retroviruses followed by selection with G418. The expression of p16 was detected by Northern and Westem blots. Cell biological characteristics, including cell growth rate, cell cycle and tumorigenesis in nude mice were assessed.Results Both mRNA and protein expression of p16 in Bcap-37 cells transfected with retroviral vector containing the p16 gene were much higher than that in Bcap-37 cells transfected with empty vector or parental Bcap-37 cells. Cell overexpressing the p16 gene exhibited a slower rate of growth, a higher percentage of cells in the G1 phase, and smaller tumors in nude mice, compared with parental Bcap-37 cells and cells transfected with empty vector.Conclusion Overexpression of the p16 gene could suppress the growth of Bcap-37 breast cancer cells by arresting the cell cvcle at the G1 to S-phase.

A novel anticancer property of Lycium barbarum polysaccharide in triggering ferroptosis of breast cancer cells

Breast cancer is one of the most malignant tumors and is associated with high mortality rates among women.Lycium barbarum polysaccharide(LBP)is an extract from the fruits of the traditional Chinese herb,L.barbarum.LBP is a promising anticancer drug,due to its high activity and low toxicity.Although it has anticancer properties,its mechanisms of action have not been fully established.Ferroptosis,which is a novel anticancer strategy,is a cell death mechanism that relies on iron-dependent lipid reactive oxygen species(ROS)accumulation.In this study,human breast cancer cells(Michigan Cancer Foundation-7(MCF-7)and MD Anderson-Metastatic Breast-231(MDA-MB-231))were treated with LBP.LBP inhibited their viability and proliferation in association with high levels of ferroptosis.Therefore,we aimed to ascertain whether LBP reduced cell viability through ferroptosis.We found that the structure and function of mitochondria,lipid peroxidation,and expression of solute carrier family 7 member 11(SLC7 A11,also known as x CT,the light-chain subunit of cystine/glutamate antiporter system X_(c)^(-))and glutathione peroxidase 4(GPX4)were altered by LBP.Moreover,the ferroptosis inhibitor,Ferrostatin-1(Fer-1),rescued LBP-induced ferroptosis-associated events including reduced cell viability and glutathione(GSH)production,accumulation of intracellular free divalent iron ions and malondialdehyde(MDA),and down-regulation of the expression of x CT and GPX4.Erastin(x CT inhibitor)and RSL3(GPX4 inhibitor)inhibited the expression of x CT and GPX4,respectively,which was lower after the co-treatment of LBP with Erastin and RSL3.These results suggest that LBP effectively prevents breast cancer cell proliferation and promotes ferroptosis via the x CT/GPX4 pathway.Therefore,LBP exhibits novel anticancer properties by triggering ferroptosis,and may be a potential therapeutic option for breast cancer.

Aidi Injection (艾迪注射液) Alters the Expression Profiles of MicroRNAs in Human Breast Cancer Cells

Objective: To investigate the effects of Aidi Injection (艾迪注射液 ADI) on the MicroRNAs (miRNA) expression profiles in human breast cancer cells and explore the potential targets of the cancer treatment. Methods: MCF-7 breast cancer cells were grown in RPMI 1640 medium supplemented with different concentrations of ADI. The inhibition of cell proliferation was measured by MTT assay. MCF-7 cells were treated by ADI with above 50% inhibiting concentration (IC50) for 48 h. The expression profiles of miRNA in ADI-treated and ADI-untreated MCF-7 cells were detected with miRNA microarray chips and the array data were verified by quantitative RT-PCR. MCF-7 cells were transiently transfected with miRNA mimics by liposome method. Potential mRNA targets were predicted by informatics analysis with TargetScan and PicTar software. Results: ADI significantly inhibited the proliferation of MCF-7 cells in a dose-dependent manner. The IC50 of ADI was 55.71 mg/mL after treatment for 48 h. The 60 mg/mL ADI was used as the therapeutic drug concentration. Microarray analysis identified 45 miRNAs that were up-regulated and 55 miRNAs that were down-regulated in response to ADI treatment. Many ADI-induced miRNAs were related to breast cancers. The microarray data were validated by qRT-PCR. Ectopic expression of 100 nmol/L mir-126 mimics significantly inhibited the proliferation of MCF-7 cells. The 12 potential target genes of mir-126 were predicted by both TargetScan and PicTar software. Conclusions: The miRNA may serve as therapeutic targets, and the modulation of miRNA expression is an important mechanism of ADI inhibiting breast cancer cell growth.

EGFR antisense RNA blocks expression of the epidermal growth factor receptor and partially reverse the malignant phenotype of human breast cancer MDA-MB-231 cells

The effects of human EGFR to the malignant phenotype of human breast cancer cell line MDA-MB-231 were investigated experimentally. A retroviral vector containing a 5'1350bp fragment of the human EGFR cDNA in the antisense orientation was transfected into targeted cells by lipofectamine. The effects on cell proliferation, cell cycle and adherent ability to extracellular matrix (ECM) components were studied after the expression of antisense transcripts to EGFR 5'1350bp fragment in target cells. In vitro studies showed that the growth ability of the transfected cells was partialy inhibited in comparison to parental cells and to cells transfected with the plasmid containing the neomycin resistance gene only. It was found that EGF (10ng/ml) had an augmenation effect on the growth of transfected MDA-AS10 cells but not MDA-MB-231 cells.Flow cytometric analysis showed that the cell cycle of the transfected cells was abnormal with a decrease of cells in G2/M and S phases and an increase of cells in G1 phase,indicating a blockage in phase G1. Immunofluorescence of EGFR expression in transfectants stained with an antiEGFR antibody was decreased and their growth in soft agarose was also severely impaired. The transfected cells showed less adherence to laminin (LN) and fibronectin (FN). In short, EGFR antisense RNA decreases the expression of EGFR on MDA-MB-231 cells and partially reverses their malignant phenotype as well.Effects of antisense EGFR on human breast cancer MDA-MB-231 cells

Novel 2H-pyrazolo[4,3-c]hexahydropyridine derivatives: Synthesis, crystal structure, fluorescence properties and cytotoxicity evaluation against human breast cancer cells

A series of novel 2H-pyrazolo[4,3-c]hexahydropyridine derivatives （II） have been designed and synthesized. The target com- pounds have been identified by elemental analysis and spectral （1H NMR, IR, and MS） data and the absolute configuration of compound （IIl） was confirmed by single crystal X-ray diffraction. The cytotoxicity of the target compounds have been evalu- ated in vitro against two human breast cancer cell lines MCF-7 and MDA-MB-231 by MTT assay. Most compounds exhibited good inhibition, and compounds II21 （IC50 = 4.7 μM for MCF-7 and IC50 = 9.3 μM for MDA-MB-231）, 1133 （IC50 = 2.4 μM for MCF-7 and IC50 = 4.2 gM for MDA-MB-231） and 114o （IC50 = 3.3 μM for MCF-7 and IC5o =8.6 μM for MDA-MB-231） dis- played better inhibitory activity than 5-fluorouracil （IC50 = 4.8 μM for MCF-7 and IC50 = 9.6 I, tM for MDA-MB-231, respec- tively）. Flow cytometric analysis and DNA fragmentation suggest that II33 is cytotoxic and able to induce the apoptosis of MCF-7 cells. The fluorescence properties of compounds IIl, II6, II11,II16, II23, Il2s, and II3s were also studied and compound Ilzs afforded the highest photoluminescence quantum yield （38%）.

A comparison study of the cytotoxicity of salinomycin and salinomycin sodium toward human breast cancer stem cells as well as breast cancer cells

Salinomycin（SAL）,a polyether antibiotic isolated from Streptomyces albus,is widely used as an anticoccidial drug in poultry and other livestock and is furthermore fed to ruminescent animals to improve nutrient absorption and feed efficiency.It has recently been shown to act as a specific inhibitor of cancer stem cells.At present,the price of salinomycin sodium（SAL-Na） is 10 fold lower than that of salinomycin,however,there is no report about the comparison of the inhibitory effects of SAL and SAL-Na on cancer stem cells as well as cancer cells.In the present study,side population cells（SP cells）and non-SP cells （NSP cells）sorted from human breast cancer cell line MCF-7 were chosen as the models of cancer stem cells and cancer cells, respectively.SRB assay was performed to compare the cytotoxicity of SAL and SAL-Na.First of all,SP cells were sorted from MCF-7 cells via FACSDiva flow cytometry.Secondly,the sorted SP cells were identified with the surface makers（CD44~＋/CD24^-） of breast cancer stem cells.Finally,the inhibitory effects of SAL and SAL-Na were evaluated on the sorted SP cells and NSP cells.Results showed that,as compared to breast cancer cells,the inhibitory effect of free SAL or free SAL-Na was more potent in breast cancer stem cells.Furthermore,the inhibitory effects of free SAL and free SAL-Na had no significant difference for the SP cells as well as the NSP cells when they were in the same concentration.Thus,it suggested that salinomycin sodium should be considered as a potential candidate to take the place of salinomycin in cancer stem cells research,due to their similar inhibitory effects on cancer stem cells.