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The miRNAs have been shown to be involved in breast cancer. The aim of the present research was to evaluate the impacts of extract from Euphorbia szovitsii FischC.A. Mey on the expression level of microRNAs in triple-negative breast cancer (MDA-MB-231) cell line.The alterations in the expression level of miRNAs in MDA-MB-231 cell line exposed to the extract of E. szovitsii were determined exploiting qRT-PCR technique. The expression of MDA-MB-231 cell microRNAs including miR-15, miR-16, miR-21, miR-29, miR-34a, miR-146b, miR-151, miR-155, miR-181b, miR-221, miR-222, and Let-7 was evaluated at 24 and 48 h after treatment with the E. szovitsii extract. The treatment of MDA-MB-231 cells with E. szovitsii caused a significant elevation in the expression of miR-155, miR-146b (P0.05), miR-16, miR-21, miR-151 (P0.01), and miR-34a (P 0.001) after 24 h, and also miR-155, Let-7 (P 0.05), miR-15, miR-29, miR-151 (P 0. 01), miR-146b and miR-34a (P0.001) after 48 h.The qRT-PCR findings at 24 and 48 h after treatment revealed that the MDA-MB-231 cell line in the presence of E. szovitsii extract showed an alteration in the expression profile of miRNAs implicated in the induction of cell proliferation, apoptosis and migration. These results may be helpful in determining the anticancer activity of E. szovitsii in MDA-MB-231 cell line.

Self-assembled nanocarriers (SANs) as a novel colloidal controlled delivery for docetaxel trihydrate (DTX) were engineered by high-pressure homogenization method to overcome the several clinical problems. Drug-excipient compatibility was studied using DSC and FTIR spectroscopy. The fabricated SANs was characterized by particle size, zeta potential, and SEM. QbD based central composite design of experiment was employed for formula optimization. The cell viability of DTX-hydroalcoholic solution (DTX-HA) and DTX-loaded SANs has been determined in MDA-MB-231 cell line by MTT assay. The stability study of selected SANs formulations were carried out at various storage conditions as per ICH guidelines. The summary of results obtained shows high drug content with higher entrapment efficiency (91.23 ± 3.41% w/w) of DTX-loaded SANs. It shows diffusion controlled release of DTX over the period of 12 h which is higher than DTX-HA solution, releases the DTX within 4 h. The MTT assay expressed lower cellular viability and improved cell inhibition leads to increase cytotoxicity of formulations towards cells. The stability study reveals stability of DTX-loaded SANs formulations at various storage conditions over a period of three months. The strong experimental evidence confirms the SANs as an effective approach to formulate the controlled delivery system of antineoplastics with improved stability.

BackgroundThe humanSH3 domain Binding Glutamic acid Rich Like 3(SH3BGRL3) gene is highly conserved in phylogeny and widely expressed in human tissues. However, its function is largely undetermined. The protein was found to be overexpressed in several tumors, and recent work suggested a possible relationship with EGFR family members.We aimed at further highlighting on these issues and investigated SH3BGRL3 molecular interactions and its role in cellular migration ability.ResultsWe first engineered the ErbB2-overexpressing SKBR3 cells to express exogenous SH3BGRL3, as well as wild type Myo1c or different deletion mutants. Confocal microscopy analysis indicated that SH3BGRL3 co-localized with Myo1c and ErbB2 at plasma membranes. However, co-immunoprecipitation assays and mass spectrometry demonstrated that SH3BGRL3 did not directly bind ErbB2, but specifically recognized Myo1c, on its IQ-bearing neck region. Importantly, the interaction with Myo1c was Ca2+-dependent.A role for SH3BGRL3 in cell migration was also assessed, as RNA interference of SH3BGRL3 in MDA-MB-231 cells, used as a classical migration model, remarkably impaired the migration ability of these cells. On the other side, its over-expression increased cell motility.ConclusionThe results of this study provide insights for the formulation of novel hypotheses on the putative role of SH3BGRL3 protein in the regulation of myosin-cytoskeleton dialog and in cell migration. It could be envisaged the SH3BGRL3-Myo1c interaction as a regulation mechanism for cytoskeleton dynamics. It is well known that, at low Ca2+concentrations, the IQ domains of Myo1c are bound by calmodulin. Here we found that binding of Myo1c to SH3BGRL3 requires instead the presence of Ca2+. Thus, it could be hypothesized that Myo1c conformation may be modulated by Ca2+-driven mechanisms that involve alternative binding by calmodulin or SH3BGRL3, for the regulation of cytoskeletal activity.

We have previously reported the anti-metastatic effects of 2-methoxy-1,4-naphthoquinone (MNQ) against MDA-MB-231 cell line.To investigate the molecular mechanism underlying the anti-metastatic effects of MNQ towards MDA-MB-231 cell line via the comparative proteomic approach.Differentially expressed proteins in MNQ-treated MDA-MB-231 cells were identified by using two-dimensional gel electrophoresis coupled with tandem mass spectrometry. Proteins and signalling pathways associated with the identified MNQ-altered proteins were studied by using Western blotting.Significant modulation of MDA-MB-231 cell proteome was observed upon treatment with MNQ in which the expressions of 19 proteins were found to be downregulated whereas another eight were upregulated (1.5 fold, p0.05). The altered proteins were mainly related to cytoskeletal functions and regulations, mRNA processing, protein modifications and oxidative stress response. Notably, two of the downregulated proteins, protein S100-A4 (S100A4) and laminin-binding protein (RPSA) are known to play key roles in driving metastasis and were verified using Western blotting. Further investigation using Western blotting also revealed that MNQ decreased the activations of pro-metastatic ERK1/2 and NF-κB signalling pathways. Moreover, MNQ was shown to stimulate the expression of the metastatic suppressor, E-cadherin.This study reports a proposed mechanism by which MNQ exerts its anti-metastatic effects against MDA-MB-231 cell line. The findings from this study offer new insights on the potential of MNQ to be developed as a novel anti-metastatic agent.

A new combination of sulforaphane (a natural compound obtained from Brassicaceae vegetables) and the cytostatic drug doxorubicin was entrapped in nanometer-sized liposomes. In vitro experiments were performed to investigate the cytotoxicity of these structures on the human breast cancer cell line MDA-MB-231. Confocal microscopy studies revealed enhanced cellular endocytotic internalization, followed by the release of the examined combination from the lysosomes. The in vitro interaction analysis using the Chou-Talalay approach showed high synergistic activity of the examined combination. This synergistic activity enables a considerable reduction in cytostatic dosage and an increase in cancer treatment efficiency.

Triple-negative breast cancers (TNBCs) are aggressive cancers that do not benefit from hormonal therapy or therapies that target HER2 receptors. Insulin-like growth factor 1 receptor (IGF-1R), which has been shown to be overexpressed in breast cancer, activates numerous downstream kinases that associate with cell proliferation and survival. This study compared the effects caused by dual treatments targeting IGF-1R, PI3K, mTORC, or MEK with those by single treatments in a TNBC cell line, MDA-MB-231. We used small-molecule kinase inhibitors, namely, NVP-AEW541, NVP-BKM120, KU0063794, and PD0325901 to target IGF-1R, PI3K, mTORC, and MEK, respectively. Combination treatments of PD0325901 with NVP-AEW541, NVP-BKM120 or KU0063794 and NVP-AEW541 with KU0063794 demonstrated a significant synergistic growth inhibition. These dual treatments increased apoptosis and/or cell cycle arrest at G0/G1 phase and enhanced the inhibition of phosphorylation of Akt or downstream molecules of mTORC1, as compared to the single treatments. Our study suggests that targeting multiple kinases in IGF-1R signaling may be a promising therapeutic approach.

The main intention of this study was the investigation of impact of natural biologically active ligands of nuclear retinoid/retinoid X receptors (all-trans and 9-cis retinoic acid) on proteomic pattern in human estrogen receptor negative breast cancer cell line MDA-MB-231. For this purpose, proteomic strategies based on bottom-up method were applied. The total cell proteins were extracted utilizing a commercially Radio-Immunoprecipitation Assay (RIPA) buffer and separated on 2D sodium dodecyl sulfate polyacrylamide gel electrophoresis (2D SDS-PAGE). The proteins were subsequently digested in-gel by trypsin and their characterization was achieved by MALDI-TOF/TOF. By employing PDQuest™ software, we identified more than 50 proteins affected by retinoic acid isomers. For more information, 9 proteins which are associated with tumor process were selected. We determined that derivatives of retinoic acid led to significantly reduced level of proteins belonging to metabolic pathway (e.g. glyceraldehyde-3-phosphate dehydrogenase or pyruvate kinase 2) or to other cellular processes as apoptosis, regulation of transcription process or epithelial-mesenchymal transition (e.g. annexins, nucleoside diphosphate kinase B, vimentin). On the other hand all-trans retinoic acid treatment indicates up-regulated effect for heterogeneous nuclear ribonucleoprotein A2/B1.

Background: Breast cancer is the most diagnosed and the major cause of cancer death in women worldwide. Metastasis is the main cause of these deaths. The metastatic cascade involves multiple steps and it has been described that adrenergic receptors can modulate this process at multiple levels. However, β-adrenergic action in breast cancer is controversial. We have previously shown that β-adrenergic agonists inhibit cell proliferation and tumor growth of numerous breast cancer models. Objective: The purpose of the present investigation was to evaluate adrenergic effect in parameters related to tumor progression (migration, invasion and metastases) in two human breast cancer cell lines. Method: Migration was assessed in IBH-6 and MDA-MB-231 cells by time-lapse videomicroscopy and modified Boyden chambers. Invasion was evaluated by Transwells coated with Matrigel and expression of pro-metastatic genes was determined by RT-qPCR. Experimental metastases studies were performed by injection of the cells in the tail vein of NSG immuno-deficient mice. Results: In both cell lines, salbutamol (β2-agonist) and propranolol (β-blocker) significantly diminished cell migration while epinephrine exerted opposite effects. Moreover, salbutamol inhibited invasion of both breast cancer cell lines and enhanced adhesion to extracellular matrix. Salbutamol treatment was also able to decrease the expression of pro-metastatic genes in MDA-MB-231 cells. Finally, this compound decreased the number and size of MDA-MB-231 lung experimental metastases in NSG immuno- deficient mice. No effect on the establishment of IBH-6 metastases was observed. Conclusion: Our results suggest that salbutamol could be an effective adjuvant drug for the treatment of metastatic breast cancer. Fil: Rivero, Ezequiel Mariano. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentina Fil: Perez, Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentina Fil: Gargiulo, Lucía. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentina Fil: Entschladen, Frank. Witten/Herdecke University; Alemania Fil: Zänker, Kurt. Witten/herdecke University; Alemania Fil: Bruzzone, Ariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; Argentina Fil: Luthy, Isabel Alicia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentina

Interaction between urokinase-type plasminogen activator (uPA) and its receptor (uPAR) plays an important role in the progression of numerous cancer types including breast cancer by promoting tumor initiating, proliferation, invasion and metastasis. Hence, disruption of this interaction inhibits their downstream cascades and subsequently tumor growth. For this, we created two series of 8 and 10 amino acids linear peptides, derived from uPA binding region to target uPAR and studied the inhibition of proliferation in MDA-MB-231 cell line. Results revealed that all of the 10-mer peptides inhibited breast cancer cell proliferation significantly with maximum 40% inhibition of 103 peptides. Meanwhile, none of the 8-mer peptides showed significant toxicity. Current results indicate that the linear 10-mer peptides which mimic a small part of a sequence of a binding domain of uPA to uPAR could be exploited to design a novel class of anti-cancer agents.

27-O-(E)-p-coumaric acyl ursolic acid( DY-17) from Ilex latifolia is a compound of the monomer. To investigate the DY-17 inducing apoptosis in the human breast cancer cell line, the MDA-MB-231 cells were used as research object in this experiment. The proliferation activity of the MDA-MB-231 cells stimulated with the different concentrations of DY-17 (20, 40 µmol · L(-1)) was detected at different time( 12, 24, 36, 48, 60,72 h) . We surveyed the DY-17 inducing apoptosis of the MDA-MB-231 cells with the fluorescent staining technology. The rate of MDA-MB-231 cells apoptosis and necrosis was determined by flow cell cytometry (FCC). Moreover, expression of JNK, phosphorylated JNK, Bax, PARP shear and caspase-3 shear related to JNK/SAPK pathways were investigated in every group ( control group, EGF group, EGF + DY-17 40 µmol · L(1) group and EGF + SP600125 group) with Western blot. The MTT results showed that, in the presence of DY-17, the proliferation activity of MDA-MB-231 cells decreased in a dose-dependent and time-dependent manner. The apoptosis and necrosis rates of MDA-MB-231 cells with DY-17(20, 40 µmol · L(-1)) groups was respectively 31.86%, 49.91% by flow cytometry and significantly increased compared with control group under Fluores- cence microscopy. Up-regulation of the JNK phosphorylation protein expression was observed in EGF group compared with control group. In addition, markedly decreased the expression of JNK phosphorylation protein were also surveyed in EGF + DY-17 40 µmol · L(-1) group compared with EGF group. The expression of Bax, shear PARP and shear caspase-3 protein in EGF + DY-17 40 µmol · L(-1) group were significantly increased in comparison with EGF group. The results showed DY-17 induced apoptosis of human breast cancer MDA-MB-231 cell line related to down-regulating JNK/SAPK signal pathways.

Ethopharmacological relevance Uncaria tomentosa (Willd.) DC. (Rubiaceae) (Ut), also known as cat's claw, is a woody liana widely spread throughout the Amazon rainforest of Central and South America, containing many chemical constituents such as oxindole alkaloids, which are responsible for various biological activities. Since ancient times, the indigenous people of Peru have used it as a bark infusion for the treatment of a wide range of health problems gastric ulcers, arthritis and rheumatism. Recently, Ut is distributed worldwide and used as an immunomodulatory and anti-inflammatory herbal remedy. Additionally, U. tomentosa also has antitumural activity. However, little is known about the action of U. tomentosa on the purinergic system mechanisms, which is involved in tumor progression. Aim of the study Considering the pharmacological properties of U. tomentosa, we sought to evaluate the hydroalcoholic extract U tomentosa is able to influence the purinergic system in breast cancer cells, MDA-MB-231. Through the activity and expression of ectonucleotidases (NTPDase – CD39; Ecto-5′-nucleotidase – CD73) and purinergic repceptores (P2X7 and A1). Materials and methods A hydroalcoholic extract was prepared in two concentrations, 250 and 500 μg/mL. (Ut250; Ut500). The effect of these concentrations on the activity and expression of ectonucleotidases, as well as on the density of purinergic receptors were investigated in MDA-MB-231 breast cancer cells. Cells were treated with the hydroalcoholic extract of Uncaria tomentosa and/or doxorubicin (Doxo 1 μM; Ut250+Doxo; Ut500+Doxo) for 24 h. Results Although the results were not significant for the hydrolysis of the ATP, they presented an increase in the ADP hydrolysis in the Ut500+Doxo group when compared to the control group. Additionally, the activity of 5′-nucleotidase was inhibited in all groups when compared with the untreated group of cells. Inhibition of the enzyme was more evident in groups with U. tomentosa per se. The expression of CD39 was increased in the Ut250 and Ut250+Doxo groups when compared to the control group. No changes were found in the CD73 expression. Furthermore, a reduction in the density of the P2X7 receptor in all treated groups was detected. On the other hand, the density of the A1 receptor increased in all groups compared to the control group, with the exception of the Ut500+Doxo group. Conclusion Therefore, we conclude that hydroalcoholic extract of U. tomentosa may be responsible for the reduction of adenosine levels in the extracellular medium, which accelerates tumor progression. Interestingly, the dysregulation of A1 and P2X7 receptors in the MDA-MB-231 cells exacerbate the proliferation of this cells and U. tomentosa treatment may be stimulate the antitumor activity of adenosine A1 receptor and control the P2X7 effects. Our study demonstrates the significant participation of purinergic pathway in the regulation of MDA-MB-231 progression; additionally, U. tomentosa treatment alone or combined with chemotherapy may favor the action of doxorubicin.

Lactobacilli are probiotics shown to have antitumor activities. In addition, they can regulate gene expression through epigenetic mechanisms. In this study, we aimed to assess anti tumor activities of Lactobacillus acidophilus and Lactobacillus crispatus on the MDA-MB-231 breast cancer cell line. The effects of culture supernatants were determined by MTT [3-(4,5-dimethylthiazol-2-y-2,5-diphenyltetrazolium bromide] assay. Changes in expression of 5 cancer-testis antigens (CTAs), namely AKAP4, ODF4, PIWIL2, RHOXF2 and TSGA10 ,were analyzed by quantitative real time RT-PCR. The culture supernatants of the 2 lactobacilli inhibited MDA-MB-231 cell proliferation. In addition, transcriptional activity of all mentioned CTAs except AKAP4 was significantly decreased after 24 hour treatment with culture supernatants. This study shows that Lactobacillus acidophilus and Lactobacillus crispatus have antiproliferative activity against MDA-MB-231 cells. In addition, these lactobacilli could decrease transcriptional activity of 4 CTAs. Previous studies have shown that expression of CTAs is epigenetically regulated, so it is possible that lactobacilli cause this expression downregulation through epigenetic mechanisms. As expression of CTAs in cancers is usually associated with higher grades and poor prognosis, downregulation of their expression by lactobacilli may have clinical implications.

The aim of this study was to establish a bioluminescent MDA-MB-231 cell line stably expressing luciferase and green fluorescent protein for the generation of a xenografted model of human triple-negative breast cancer (TNBC) in nude mice. Lentivirus vectors carrying eGFP, firefly luc2 and neo fusion genes were used to transduce the MDA-MB-231 human TNBC cells in vitro. After 8 weeks of G418 selection, eGFP and luc2 expression was determined using a fluorescence microscope and a Xenogen IVIS200 bioluminescent imaging system, respectively. The MTT, transwell invasion and wound healing assays were performed to confirm whether cellular proliferation, invasion and migration were altered by lentiviral infection. Cells were orthotopically implanted into female BALB/c nude mice to test the sensitivity and stability of reporter gene expression. Growth of the tumors was monitored with the in vivo imaging system once a week until they were large enough for experiments. The tumor tissues were resected for histology, and cancer cells were harvested for culture. The lentivirus-transduced MDA-MB-231 cells could stably express luc2 and eGFP, and the luciferase activity reached 9689 photons/sec/cell. Meanwhile, no significant difference in biological activities was observed between the lentivirus-transduced MDA-MB-231 cells and parental cells. An orthotopically implanted tumor model of human TNBCs was successfully established in BALB/c nude mice. Lentiviruses may be ideal carriers for luciferase genes due to their highly efficient infectivity and stable transgene expression. The modified MDA-MB-231 cell line stably expressing luciferase could be detected, allowing for immediate and sensitive detection of metastasis sites in nude mice. As the eGFP and luc2 combination are superior to single reporter genes in their ability to mark cells in vivo and in vitro, these cells may provide a visualizable, convenient and sensitive platform for research on the mechanisms of metastasis and the development of new antitumor drugs for human TNBC.

To establish a bioluminescent MDA-MB-231 cell line which can stably express luciferase and green fluorescent protein to allow bioluminescent imaging in nude mouse models bearing human triple-negative breast cancer xenografts.The lentivirus carrying luc2, eGFP and neo fusion genes were packaged in 293T cells via calcium phosphate co-precipitation. Human triple-negative breast cancer cell line MDA-MB-231 was infected by the lentivirus, and the positive cell clones were tested for eGFP and luc2 expressions by fluorescence microscopy and Xenogen IVIS200 bioluminescent imaging system, respectively. MTT assay, transwell invasion assay and wound healing assay were performed to evaluate the changes in the proliferation, invasion and migration abilities of the infected cells. The cells were then orthotopically implanted into the right second mammary fat pat of female BALB/c nude mice. The tumor growth was monitored by the in vivo imaging system every week, and the tumor tissues were harvested to evaluate the in vivo stability and tumorigenicity of the modified cells using cryosection and HE staining.The lentivirus-infected MDA-MB-231cells could stably express luc2 and eGFP, and the luciferase activity reached 9689 phontons/s/per cell. No significant changes occurred in the biological activities of the lentivirus-infected MDA-MB-231 cells. We successfully established the nude mouse model bearing orthotopically implanted human triple-negative breast cancer cells.The modified MDA-MB-231 cell line can be detected sensitively at the primary implantation site and distant metastasis site in nude mice, which provides a convenient and sensitive platform for the research of metastatic mechanism and new antitumor drugs of human triple-negative breast cancer. The combination of eGFP and luc2 is superior to single reporter gene.

To investigate the effect of proteasomes reactivator REG gamma on cell cycle and apoptosis in vitro and in vivo. In vitro, we first constructed recombinant plasmid of PcDNA3.1-REGgamma and then transfected REGgamma into MDA-MB-231 cell line. We confirmed the transfection efficiency by Western blot. Subsequently, we observed cell growth, cycle and colony formation. Specific proliferative molecule proliferating cell nuclear antigen (PCNA) and apoptosis related signal molecule Caspase-3 was assayed by immmunohistochemistry and absorption spectrometry, respectively. In vivo, we successfully established transplantation tumor nude mice model. We determined REGgamma mRNA level in the transplantation tumor tissue. Then, FCM was used to determine cell cycle, apoptosis and CD16. Finally, we employed immunohistochemistry to determine P21 positive expression. However, the cells transfected with REGgamma grew more rapidly compared with non-transfected ones. Increased cells were observed in S+G2+M phase and S phase in the REGgamma transfected group. PCNA expression level in the transfected cells was higher than that in non-transfected ones. In vivo, we observed the similar phenomenon including more rapid tumor growth, higher REGgamma mRNA expression, decreased cells number in G0/G1 phase and G2/M phase, increased cells in S phase and decreased apoptosis in the transfected group. In the study of related molecules, we also found related molecules P21 and CD16 positive expression rate were obviously lower than non-infected ones. In present study, we found oncogenicity of MDA-MB-231 cell transfected with REGgamma was enhanced, which might be realized via REGgamma promoting cell growth, inhibiting cell apoptosis, degrading P21 and suppressing activation of NK, suggesting REGgamma promoting tumor growth is a process involving multiple factor mechanisms.

Normal human somatic cells have a limited division potential when they grow in vitro. It is believed that shortening of telomeres, specialized structures at the chromosome ends, controls cell growth. When one telomere achieves critical minimal length, the cell cycle control mechanism recognizes it as a DNA damage and cause exit from cell cycle in G1-phase. Due to the fact that it is not possible to extend the telomeres in normal cells, this non-dividing state is prolonged indefinitely, and it is known as cellular senescence. Immortal cell line MDA-MB-231 has an active telomerase, which stops shortening of their telomeres and allows them permanent divisions. However, there is a fraction of cells that do not divide during several days in culture as it was documented for some other tumor cell lines. The combination of few methods made it possible to isolate these non-growing cells and compare them with the fraction of fast growing cells from the same culture. Although non-growing fraction contains a significant percentage of typical senescent cells, both fractions have an equal telomerase activity and telomere length. In this paper we discuss possible mechanisms that cause appearance of observed non-growing fraction of cells in immortal MDA-MB-231 cell line which point to stress and genome instability rather than variation in telomerase activity or telomere shortening among individual cells.

Breast cancer (BC) is the most prevalent cancer and the one with the highest mortality among women worldwide. Although the molecular classification of BC has been a helpful tool for diagnosing and predicting the treatment of BC, developments are still being made to improve the diagnosis and find new therapeutic targets. Mitochondrial dysfunction is a crucial feature of cancer, which can be associated with cancer aggressiveness. Although the importance of mitochondrial dynamics in cancer is well recognized, its involvement in the mitochondrial function and bioenergetics context in BC molecular subtypes has been scantly explored. In this study, we combined mitochondrial function and bioenergetics experiments in MCF7 and MDA-MB-231 cell lines with statistical and bioinformatics analyses of the mitochondrial proteome of luminal A and basal-like tumors. We demonstrate that basal-like tumors exhibit a vicious cycle between mitochondrial fusion and fission; impaired but not completely inactive mitochondrial function; and the Warburg effect, associated with decreased oxidative phosphorylation (OXPHOS) complexes I and III. Together with the results obtained in the cell lines and the mitochondrial proteome analysis, two mitochondrial signatures were proposed: one signature reflecting alterations in mitochondrial functions and a second signature exclusively of OXPHOS, which allow us to distinguish between luminal A and basal-like tumors.

In this work, mixed ligand complexes of Co(II) Ni(II) and Cu(II) were synthesized using quercetin and diimine (1,10-phenanthroline or 2,2 '-bipyiridine) ligands. The obtained Ni(II) and Co(II) complexes are new and the Cu(II) complexes are synthesized by different method from the literature. The characterization of complexes was performed by elemental analysis, thermogravimetric analysis, ESI-MS, UV-visible and infrared spectral analyses, magnetic susceptibility and molar conductivity measurements. It was found that quercetin, diimine and metal(II) ion form 1:1:1 complexes. Resulting data supported octahedral geometry for Ni(II) and Co(II) complexes and square pyramidal geometry for Cu(II) complexes. The proposed compositions are [Co(queH-1)Cl(phen)(H2O)]center dot 2H(2)O (1, queH = quercetin, phen = 1,10-phenanthroline), [Ni(queH-1)Cl(phen)(H2O)]center dot 2H(2)O (2), [Cu(queH-1)Cl(phen)]center dot 2.5H(2)O (3) and [Cu(queH-1)Cl(bpy)]center dot 2H(2)O (4, bpy = 2,2 '-bipyiridine). Antioxidant capacity and total phenolic content of complexes measured by Folin-Ciocalteu and ABTS methods. Anti-cancer effect of these compounds were tested against different cancer cells (A549, PC-3, HeLa and MCF-7). Apoptosis identified by the fluorescence imaging, caspase cleaved cytokeratin-18 and flow cytometry analysis (annexin V, caspase 3/7, mitochondria membrane potential and oxidative stress). As a result, Cu(II) complexes are more effective than the other compounds and Complex 3 is a promising anti-cancer compound against breast cancer MCF-7 and MDA-MB-231 cells (IC50 values are 2.4 and 5.4 mu M for 48 h, respectively). Flow cytometry analysis exhibited that Complex 3 caused apoptosis in MCF-7 cells. These results support that Complex 3 has anticancer activity and can be a potential anticancer agent especially in breast cancer. WOS:000519936700015 31832781 Q2

The main aim of this study is to assess the safety and antitumor efficacy of a palladium(II) (Pd)-saccharinate complex with terpyridine. To characterize the Pd(II) complex in vitro, its cytotoxicity was evaluated using a water-soluble tetrazolium salt cell viability assay and the mechanism of cell death was assessed by DNA fragmentation/condensation and live cell imaging analyses. The antitumor efficacy and safety of the Pd(II) complex in-vivo were examined by analyzing reduction in tumor size, changes in body and organ weight, histopathological analysis of liver, kidney, and tumor sections, and biochemical analysis of serum in C57BL/6 mice. Our results showed that the Pd(II) complex was more cytotoxic to cancer cells than noncancer cell lines and caused cell death through apoptotic pathways. The treatment of the Pd(II) complex in tumor-bearing mice effectively reduced the tumor size at half the dose used for cisplatin. The Pd(II) complex appeared to exert less liver damage than the cisplatin-based complex on changes in the hepatic enzymes levels in the serum. Hence, the complex appears to be a potential chemotherapeutic drug with high antitumor efficacy and fewer hepatotoxic complications, providing an avenue for further studies. Anti-Cancer Drugs 28: 898-910 Copyright (C) 2017 Wolters Kluwer Health, Inc. All rights reserved. Scientific and Technological Research Institute of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) This work was supported by the internal funding of The Scientific and Technological Research Institute of Turkey (TUBITAK). WOS:000408162400009 28657910 Q3

Objectives: Palladium complexes are potent and less toxic molecules in comparison to other metal based agents. Here, we characterized two palladium(II) saccharinate complexes with terpyridine for their cell cycle specificity. Materials and methods: Cells were arrested at Gl, Gl/S boundary or mitosis using mimosine, double-Thymidine block, aphidicolin, nocodazole or colcemid, and evaluated based on morphology and flow cytometry. Synchronized cells were treated with the Pd(II) complexes, and viability was measured via MTT assay. Results: While treatment of arrested cells with the Pd(II) complexes resulted in no significant change in cell death in HCT-116 and MDA-MB-231 cells, HeLa cells were more sensitive in S/G1. The main form of cell death was found to be apoptosis. Conclusions: Pd(II) complexes appear to be cell-cycle non-specific, while cell line dependent differences may be observed. Cells die through apoptosis regardless of the cell cycle stage, which makes these complexes more promising as anti-cancer agents. İstanbul Üniversitesi - 36696

// Vasiliki Gkretsi 1 , Andreas Stylianou 1 , Maria Louca 1 , Triantafyllos Stylianopoulos 1 1 Cancer Biophysics Laboratory, Department of Mechanical and Manufacturing Engineering, University of Cyprus, Nicosia, Cyprus Correspondence to: Triantafyllos Stylianopoulos, email: tstylian@ucy.ac.cy Keywords: Ras suppressor-1, extracellular matrix stiffness, invasion, tumor spheroids, atomic force microscopy Received: July 16, 2016 Accepted: February 20, 2017 Published: March 09, 2017 ABSTRACT Breast cancer (BC) is the most common malignant disease in women, with most patients dying from metastasis to distant organs, making discovery of novel metastasis biomarkers and therapeutic targets imperative. Extracellular matrix (ECM)-related adhesion proteins as well as tumor matrix stiffness are important determinants for metastasis. As traditional two-dimensional culture does not take into account ECM stiffness, we employed 3-dimensional collagen I gels of increasing concentration and stiffness to embed BC cells of different invasiveness (MCF-7, MDA-MB-231 and MDA-MB-231-LM2) or tumor spheroids. We tested the expression of cell-ECM adhesion proteins and found that Ras Suppressor-1 (RSU-1) is significantly upregulated in increased stiffness conditions. Interestingly, RSU-1 siRNA-mediated silencing inhibited Urokinase Plasminogen Activator, and metalloproteinase-13, whereas tumor spheroids formed from RSU-1-depleted cells lost their invasive capacity in all cell lines and stiffness conditions. Kaplan-Meier survival plot analysis corroborated our findings showing that high RSU-1 expression is associated with poor prognosis for distant metastasis-free and remission-free survival in BC patients. Taken together, our results indicate the important role of RSU-1 in BC metastasis and set the foundations for its validation as potential BC metastasis marker.

Besides being traditionally used to relieve hepatobiliary disorders, Cynara cardunculus L. has evidenced anticancer potential on triple-negative breast cancer (TNBC). This study highlights the antiproliferative effects of lipophilic extracts from C. cardunculus L. var. altilis (DC) leaves and florets, and of their major compounds, namely cynaropicrin and taraxasteryl acetate, against MDA-MB-231 cells. Our results demonstrated that MDA-MB-231 cells were much less resistant to leaves extract (IC50 10.39 µg/mL) than to florets extract (IC50 315.22 µg/mL), during 48 h. Moreover, leaves extract and cynaropicrin (IC50 6.19 µg/mL) suppressed MDA-MB-231 cells colonies formation, via an anchorage-independent growth assay. Leaves extract and cynaropicrin were also assessed regarding their regulation on caspase-3 activity, by using a spectrophotometric assay, and expression levels of G2/mitosis checkpoint and Akt signaling pathway proteins, by Western blotting. Leaves extract increased caspase-3 activity, while cynaropicrin did not affect it. Additionally, they caused p21Waf1/Cip1 upregulation, as well as cyclin B1 and phospho(Tyr15)-CDK1 accumulation, which may be related to G2 cell cycle arrest. They also downregulated phospho(Ser473)-Akt, without changing total Akt1 level. Cynaropicrin probably contributed to leaves extract antiproliferative action. These promising insights suggest that cultivated cardoon leaves lipophilic extract and cynaropicrin may be considered toward a natural-based therapeutic approach on TNBC.

Background: Due to the aggressive clinical behavior, poor outcome, and lack of effective specific targeted therapies, triple-negative breast cancer (TNBC) has currently been recognized as one of the most malignant types of tumors. In the present study, we investigated the cytotoxic effect of ziyuglycoside I, one of the major components extracted from Chinese anti-tumor herbal Radix Sanguisorbae, on the TNBC cell line MDA-MB-231. Methods: The underlying molecular mechanism of the cytotoxic effect ziyuglycoside I on MDA-MB-231 cells was investigated with cell viability assay, flow cytometric analysis and Western blot. Results: Compared to normal mammary gland Hs 578Bst cells, treatment of ziyuglycoside I resulted in a significant growth inhibitory effect on MDA-MB-231 cells. Ziyuglycoside I induced the G2/M phase arrest and apoptosis of MDA-MB-231 cells in a dose-dependent manner. These effects were found to be partially mediated through the up-regulation of p53 and p21WAF1, elevated Bax/Bcl-2 ratio, and the activation of both intrinsic (mitochondrial-initiated) and extrinsic (Fas/FasL-initiated) apoptotic pathways. Furthermore, the p53 specific siRNA attenuated these effects. Conclusion: Our study suggested that ziyuglycoside I-triggered MDA-MB-231 cell cycle arrest and apoptosis were probably mediated by p53. This suggests that ziyuglycoside I might be a potential drug candidate for treating TNBC.

Estrogen receptor (ER)-negative breast cancers have a worse prognosis than ER-positive cancers, being more aggressive and overexposed to stimuli leading to their progression. Hepatocyte growth factor (HGF) has been associated with proliferation, migration and invasion of tumor cells, and several tumors, including those of breast cancer, produce HGF and overexpress its receptor. Diacylglycerol kinases (Dgks), which phosphorylate diacylglycerol to phosphatidic acid, are key regulators of cell signaling. Our research was focused on their role in HGF-induced invasion of MDA-MB-231 cells, a model of ER-negative breast cancer.Dgk activity was evaluated with a kinase assay, MDA-MB-231 cell invasion via culturing of cells in matrigel-coated transwells, and anchorage-independent growth was assessed using a soft agar assay.HGF induces Dgk activation in MDA-MB-231 cells that is required for cell invasiveness. Moreover, Dgks are involved in MDA-MB-231 anchorage-independent growth.Dgks could be a target for ER-negative breast cancer therapy.

Background: Triple Negative Breast Cancer (TNBC) commonly displays Epidermal growth factor receptor (EGFR). Effective EGFR degradation results in the suppression of tumor in various models. Studies have addressed the relevance of this strategy in the treatment of TNBC. In the present study, we examined the effect of 17 β- estradiol on EGFR expression in MDA-MB-231 (TNBC) cell line and assessed whether 17 β-estradiol degrades EGFR by ubiquitination pathway. Objectives: The objectives of this study are to treat MDA-MB-231 cell lines with Cycloheximide with or without 17β-estrdiol to observe whether 17β-estradiol leads to EGFR degradation and to treat with MG-132 to assess whether degradation occurs through ubiquitination pathway. Methods: MDA-MB-231 cells were treated with 17β-estradiol (E2) and EGFR expression was studied by western blotting at different intervals by using Cycloheximide chase. To assess ubiquitination pathway of degradation of EGFR in MDA-MB-231 cell line, MG-132 was used. Results: EGFR expression was reduced with β-estradiol treatment in MDA-MB-231 cell line with Cycloheximide chase. Upon Treatment with MG-132 and E2, EGFR expression did not reduce, suggesting that Estrogen degrades EGFR by ubiquitination pathway. Conclusion: Estrogen degrades EGFR in MDA-MB-231 cells and this degradation occurs by ubiquitination.

The aim of this study was to investigate the expression of miRNA regulated by c-myc and its mechanism in three negative breast cancer (TNBC). We constructed MDA-MB-231 cell line with low expression of c-myc by lentivirus short hairpin RNA (shRNA), analyzed the miRNA expression profile of MDA-MB-231 cell line with different expression levels of c-myc by high-throughput sequencing technology, obtained differential miRNA by bioinformatics analysis and statistical analysis, and verified hsa-mir-4723-5p by Quantitative Real-time polymerase chain reaction(QRT-PCR). The target gene of hsa-mir-4723-5p was analyzed by miRDB and miRWalk database. The results showed that there were significant differences in 126 miRNAs in c-myc knockdown cell lines compared with the control group, of which 84 were significantly up-regulated and 42 were significantly down regulated. According to the results of miRNA sequencing, the miRNA closely related to the expression of c-myc was hsa-mir-4723-5p. QRT PCR showed that the expression of hsa-mir-4723-5p was down regulated in TNBC cell line MDA-MB-231 with low expression of c-myc, which was positively correlated with the expression. The target genes of hsa-mir-4723-5p were predicted according to mirdb and mirwalk database. A total of 112 target genes were obtained, and 107 target genes were related to hsa-mir-4723-5p. Through mirdb and mirwalk databases, it was found that the target gene TRAF4 of hsa-mir-4723-5p may be related to cancer pathway and affect tumor metastasis. In conclusion, the hsa-miR-4723-5p regulated by c-myc may be involved.

Triple-negative breast cancer (TNBC) is the most outrageous subtype of breast cancer. Emphasizing the urge of new approach in cancer therapy, combinational drug therapy may be proven as an effective strategy. In our previous study, we reported that coralyne (COR) with paclitaxel (PTX) efficiently decreases the proliferation of MDA-MB-231 compared with MCF-7 cell line. Thus, we studied the effect of COR and PTX in combination on apoptosis of MDA-MB-231 cell line. In silico results demonstrated that COR intercalates DNA at a minor groove. In vitro approaches revealed that in combination (COR and PTX) increases the efficacy of apoptosis in MDA-MB-231 cell line by a significant increase in G1/S phase arrest, DNA fragmentation, and change in mitochondria membrane potential. The expression of ATM and ATR a serine/threonine-protein kinase, ataxia telangiectasia and Rad3-related protein were depleted with an increase in time from 24 to 48 hours in concurrent with increased levels of γH2AX indicating that DNA damage routes cells to enter apoptosis. This was confirmed by high levels of caspase-3 and cytochrome c. Also, the decrease in the expression levels of matrix metalloproteinase-9 confirmed the antimetastatic efficacy of COR + PTX. The present study indicates that the synergistic effect of COR and PTX can enhance apoptosis in MDA-MB-231 cell line and may be proven as a potential anticancer therapy against TNBC.

Glycosphingolipid expression differs between human breast cancer stem cells (CSC) and cancer non-stem cells (non-CSC). We performed studies of viability, type of cell death, cancer stem cell percent and glycosphingolipid expression on CSC and non-CSC after treatment of MDA-MB-231 and MDA-MB-453 triple-negative breast cancer cells with a newly developed thienopyridine anticancer compound (3-amino-N-(3-chloro-2-methylphenyl)-5-oxo-5,6,7,8-tetrahydrothieno[2,3-b]quinoline-2-carboxamide, 1). Compound 1 was cytotoxic for both breast cancer cell lines and the majority of cells died by treatment-induced apoptosis. The percent of cancer stem cells and number of formed mammospheres was significantly lower. Glycosphingolipids IV6Neu5Ac-nLc4Cer and GalNAc-GM1b (IV3Neu5Ac-Gg5Cer) not reported previously, were identified in both CSCs and non-CSCs. IV6Neu5Ac-nLc4Cer had increased expression in both CSCs and non-CSCs of both cell lines after the treatment with 1, while GM3 (II3Neu5Ac-LacCer) had increased expression only on both cell subpopulations in MDA-MB-231 cell line. GalNAc-GM1b, Gb4Cer (GalNAcβ1-3Galα1-4Galβ1-4Glcβ1-1Cer) and GM2 (II3Neu5Ac-GalNAcβ1-4Galβ1-4Glcβ1-1Cer) were increased only in CSCs of both cell lines while GD3 was decreased in CSC of MDA-MB-231 cell line. Due to its effect in reducing the percentage of cancer stem cells and number of mammospheres, and its influence upon several glycosphingolipid expressions, it can be concluded that compound 1 deserves attention as a potential new drug for triple-negative breast cancer therapy.

A large number of Euphorbia species have been evaluated for anticancer effects; however, their anticancer mechanisms have not been established up to now.The present study aimed to evaluate the effects of Euphorbia microsciadia (E. microsciadia) Boiss on the modulation of micro (mi) RNAs in MDA-MB-231 cell line.As the first step, the inhibitory concentration of hydroalcoholic extract of E. microsciadia on MDA-MB-231 cells was examined using the MTT assay, bypassing 24 and 48h from seeding. The real-time quantitative Reverse Transcription Polymerase Chain Reaction (qRT-PCR) was also utilized to determine Let-7, miR-15, miR-16, miR-29, miR-151, miR-155, miR-21, miR-146b, miR-181b, miR-221, miR-222, miR-21, and miR-146b expressions in MDA-MB-231 cells, by passing 24 and 48h from treating with the extract of E. microsciadia.The results reveal the cytotoxic effects of E. microsciadia on MDA-MB-231 cell line in a dose-dependent manner. The half maximal Inhibitory Concentrations (IC50) were also equal to 275 and 240μg/ml for E. microsciadia, by passing 24 and 48h from the treatment, respectively. Furthermore, it was confirmed that, E. microsciadia had augmented the expression levels of Let-7, miR-15, miR-16, miR-29, and miR-34a, which lead to an increase in apoptosis.E. microsciadia could modulate some miRNAs involved in cell cycle arrest and apoptosis in MDA-MB-231 cell line. Accordingly, targeting miRNAs by E. microsciadia can open some newer avenues for breast cancer therapy.

Tumor cells modulate immune responses by secreting exosomes. Tumor exosomes can affect the metabolism of immune cells and increase immune inhibitory molecules such as programmed cell death protein 1 (PD-1). PD-1 inhibits the glycolysis pathway in immune cells. We investigated the role of tumor exosomes in how metabolic changes occur through the PD1-GLUT1-HK2 metabolic axisin peripheral blood mononuclear cells (PBMCs). The MDA-MB-231 cell line was cultured, serum samples from breast cancer patients were collected, and exosomes purified from serum samples and the MDA-MB-231 cell line. PBMCs were treated with purified exosomes for 72 h and, the expression of PD1-GLUT1-HK2 genes was measured by real-time PCR. Our study results showed relative expression of the HK2 gene in both groups treated with MDA-MB-231 cell line exosomes and serum exosomes of breast cancer patients was significantly increased compared to the control group (p < 0.0001). Also, the relative expression of the PD1 gene and GLUT1 gene showed a significant increase compared to the control group only in the group treated with MDA-MB-231 cell line exosomes (p < 0.0001). Therefore, Breast cancer exosomes increased the expression of key genes in the glycolysis pathway, increasing the glycolysis pathway in PBMCs. Increased expression of PD-1 could not prevent the expression of critical genes in the glycolysis pathway as in previous studies.

Background Propolis and its major constituent – caffeic acid phenethyl ester (CAPE) have good abilities on antitumor and anti-inflammation. However, little is known about the actions of propolis and CAPE on tumor in inflammatory microenvironment, and inflammatory responses play decisive roles at different stages of tumor development. To understand the effects and mechanisms of ethanol-extracted Chinese propolis (EECP) and its major constituent - CAPE in inflammation-stimulated tumor, we investigated their effects on Toll-like receptor 4 (TLR4) signaling pathway which plays a crucial role in breast cancer MDA-MB-231 cell line. Methods 80% confluent breast cancer MDA-MB-231 cells were stimulated with 1 μg/mL lipopolysaccaride (LPS). Then the cells were divided for treatment by CAPE (25 μg/mL) and EECP (25, 50 and 100 μg/mL), respectively. Cell viability, nitric oxide (NO) production and cell migration were measured by sulforhodamine B assay, chemical method and scratch assay. The levels of TLR4, MyD88, IRAK4, TRIF, caspase 3, PARP, LC3B and p62 were investigated through western blotting. The expression of TLR4, LC3B and nuclear factor-κB p65 (NF-κB p65) were tested by immunofluorescence microscopy assay. Results Treatment of different concentrations of EECP (25, 50 and 100 μg/mL) and CAPE (25 μg/mL) significantly inhibited LPS-stimulated MDA-MB-231 cell line proliferation, migration and NO production. Furthermore, EECP and CAPE activated caspase3 and PARP to induce cell apoptosis, and also upregulated LC3-II and decreased p62 level to induce autophagy during the process. TLR4 signaling pathway molecules such as TLR4, MyD88, IRAK4, TRIF and NF-κB p65 were all down-regulated after EECP and CAPE treatment in LPS-stimulated MDA-MB-231 cells. Conclusions These findings indicated that EECP and its major constituent - CAPE inhibited breast cancer MDA-MB-231 cells proliferation in inflammatory microenvironment through activating apoptosis, autophagy and inhibiting TLR4 signaling pathway. EECP and CAPE may hold promising prospects in treating inflammation-induced tumor.

The cytotoxicity of two recently synthesized triorganotin isothiocyanate derivatives, nuclear retinoid X receptor ligands, was tested and compared in estrogen-receptor-positive MCF 7 and -negative MDA-MB-231 human breast carcinoma cell lines. A 48 h MTT assay indicated that tributyltin isothiocyanate (TBT-ITC) is more cytotoxic than triphenyltin isothiocyanate (TPT-ITC) in MCF 7 cells, and the same trend was observed in the MDA-MB-231 cell line. A comet assay revealed the presence of both crosslinks and increasing DNA damage levels after the 17 h treatment with both derivatives. Differences in cytotoxicity of TBT-ITC and TPT-ITC detected by FDA staining correspond to the MTT data, communicating more pronounced effects in MCF 7 than in the MDA-MB-231 cell line. Both derivatives were found to cause apoptosis, as shown by the mitochondrial membrane potential (MMP) depolarization and caspase-3/7 activation. The onset of caspase activation correlated with MMP dissipation and the total cytotoxicity more than with the amount of active caspases. In conclusion, our data suggest that the DNA damage induced by TBT-ITC and TPT-ITC treatment could underlie their cytotoxicity in the cell lines studied.

Caffeic acid phenethyl ester, derived from natural propolis, has been reported to have anti-cancer properties. Voltage-gated sodium channels are upregulated in many cancers where they promote metastatic cell behaviours, including invasiveness. We found that micromolar concentrations of caffeic acid phenethyl ester blocked voltage-gated sodium channel activity in several invasive cell lines from different cancers, including breast (MDA-MB-231 and MDA-MB-468), colon (SW620) and non-small cell lung cancer (H460). In the MDA-MB-231 cell line, which was adopted as a 'model', long-term (48 h) treatment with 18 μM caffeic acid phenethyl ester reduced the peak current density by 91% and shifted steady-state inactivation to more hyperpolarized potentials and slowed recovery from inactivation. The effects of long-term treatment were also dose-dependent, 1 μM caffeic acid phenethyl ester reducing current density by only 65%. The effects of caffeic acid phenethyl ester on metastatic cell behaviours were tested on the MDA-MB-231 cell line at a working concentration (1 μM) that did not affect proliferative activity. Lateral motility and Matrigel invasion were reduced by up to 14% and 51%, respectively. Co-treatment of caffeic acid phenethyl ester with tetrodotoxin suggested that the voltage-gated sodium channel inhibition played a significant intermediary role in these effects. We conclude, first, that caffeic acid phenethyl ester does possess anti-metastatic properties. Second, the voltage-gated sodium channels, commonly expressed in strongly metastatic cancers, are a novel target for caffeic acid phenethyl ester. Third, more generally, ion channel inhibition can be a significant mode of action of nutraceutical compounds.

Lapatinib, one of the tyrosine kinase inhibitors (TKIs), is used to reduce epidermal growth factor family proteins overexpression. This study aims to assess the cytotoxic and genotoxic effects of lapatinib on the triple negative breast cancer cell line “MDA-MB-231”. We investigated the cytotoxicity of lapatinib by MTT assay, mode of cell death using apoptosis-necrosis assay, DNA damage using micronucleus test, EGFR protein expression by immunocytochemistry, and assessed its effect on EGFR (7p11.2 locus) and TP53 (17p13 locus) genes using interphase-FISH technique. Lapatinib induced cytotoxicity on MDA-MB-231 cell line by elevating the concentration and its IC 50 value was 32.5 μM after 24 h. Lapatinib increased apoptotic cells and micronuclei in binucleated cells gradually by increasing the concentration for 24 h. The EGFR protein expression was reduced by double fold that expressed in non-treated cells. Lapatinib enhanced deletion of EGFR gene signals highly significantly from the lowest concentration. Alternatively, lapatinib amplified signals of TP53 gene effectively by raising the concentration. In conclusion, lapatinib induced cytotoxic and genotoxic effects on MDA-MB-231 cell line. However, laptinib reduced the EGFR protein expression and EGFR signals, it raised the apoptotic cells and TP53 gene signals, which triggered extensive DNA damage. Therefore, lapatinib is an effective TKI in triple negative breast cancer cells as elucidated by its mode of cell death.

Arylamine N-acetyltransferase 1 (NAT1) expression is reported to affect proliferation, invasiveness, and growth of cancer cells. MDA-MB-231 breast cancer cells were engineered such that NAT1 expression was elevated or suppressed, or treated with a small molecule inhibitor of NAT1. The MDA-MB-231 human breast cancer cell lines were engineered with a scrambled shRNA, a NAT1 specific shRNA or a NAT1 overexpression cassette stably integrated into a single flippase recognition target (FRT) site facilitating incorporation of these different genetic elements into the same genomic location. NAT1-specific shRNA reduced NAT1 activity in vitro by 39%, increased endogenous acetyl coenzyme A levels by 35%, and reduced anchorage-independent growth (sevenfold) without significant effects on cell morphology, growth rates, anchorage-dependent colony formation, or invasiveness compared to the scrambled shRNA cell line. Despite 12-fold overexpression of NAT1 activity in the NAT1 overexpression cassette transfected MDA-MB-231 cell line, doubling time, anchorage-dependent cell growth, anchorage-independent cell growth, and relative invasiveness were not changed significantly when compared to the scrambled shRNA cell line. A small molecule (5E)-[5-(4-hydroxy-3,5-diiodobenzylidene)-2-thioxo-1,3-thiazolidin-4-one (5-HDST) was 25-fold more selective towards the inhibition of recombinant human NAT1 than N-acetyltransferase 2. Incubation of MDA-MB-231 cell line with 5-HDST resulted in 60% reduction in NAT1 activity and significant decreases in cell growth, anchorage-dependent growth, and anchorage-independent growth. In summary, inhibition of NAT1 activity by either shRNA or 5-HDST reduced anchorage-independent growth in the MDA-MB-231 human breast cancer cell line. These findings suggest that human NAT1 could serve as a target for the prevention and/or treatment of breast cancer.

Background The malignant potential of triple negative breast cancer (TNBC) is also dependent on a sub-population of cells with a stem-like phenotype. Among the cancer stem cell markers, CD133 and EpCAM strongly correlate with breast tumor aggressiveness, suggesting that simultaneous targeting of the two surface antigens may be beneficial in treatment of TNBC. Since in TNBC-derived cells we demonstrated that PLC-β2 induces the conversion of CD133high to CD133low cells, here we explored its possible role in down-modulating the expression of both CD133 and EpCAM and, ultimately, in reducing the number of TNBC cells with a stem-like phenotype. Methods A magnetic step-by-step cell isolation with antibodies directed against CD133 and/or EpCAM was performed on the TNBC-derived MDA-MB-231 cell line. In the same cell model, PLC-β2 was over-expressed or down-modulated and cell proliferation and invasion capability were evaluated by Real-time cell assays. The surface expression of CD133, EpCAM and CD44 in the different experimental conditions were measured by multi-color flow cytometry immunophenotyping. Results A CD133+/EpCAM+ sub-population with high proliferation rate and invasion capability is present in the MDA-MB-231 cell line. Over-expression of PLC-β2 in CD133+/EpCAM+ cells reduced the surface expression of both CD133 and EpCAM, as well as proliferation and invasion capability of this cellular subset. On the other hand, the up-modulation of PLC-β2 in the whole MDA-MB-231 cell population reduced the number of cells with a CD44+/CD133+/EpCAM+ stem-like phenotype. Conclusions Since selective targeting of the cells with the highest aggressive potential may have a great clinical importance for TNBC, the up-modulation of PLC-β2, reducing the number of cells with a stem-like phenotype, may be a promising goal for novel therapies aimed to prevent the progression of aggressive breast tumors. Electronic supplementary material The online version of this article (10.1186/s12885-017-3592-y) contains supplementary material, which is available to authorized users.

Diêgo dos Santos Ferreira,1,2 Samilla Dornelas Faria,1 Sávia Caldeira de Araújo Lopes,1 Cláudia Salviano Teixeira,1 Angelo Malachias,3 Rogério Magalhães-Paniago,3 José Dias de Souza Filho,4 Bruno Luis de Jesus Pinto Oliveira,2 Alexander Ramos Guimarães,2 Peter Caravan,2 Lucas Antônio Miranda Ferreira,1 Ricardo José Alves,1 Mônica Cristina Oliveira1 1Department of Pharmaceutical Products, Faculty of Pharmacy,Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil; 2Athinoula A Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA; 3Department of Physics, 4Department of Chemistry, Institute of Exact Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil Background: Despite recent advances in cancer therapy, the treatment of bone tumors remains a major challenge. A possible underlying hypothesis, limitation, and unmet need may be the inability of therapeutics to penetrate into dense bone mineral, which can lead to poor efficacy and high toxicity, due to drug uptake in healthy organs. The development of nanostructured formulations with high affinity for bone could be an interesting approach to overcome these challenges.Purpose: To develop a liposomal formulation with high affinity for hydroxyapatite and the ability to release doxorubicin (DOX) in an acidic environment for future application as a tool for treatment of bone metastases.Materials and methods: Liposomes were prepared by thin-film lipid hydration, followed by extrusion and the sulfate gradient-encapsulation method. Liposomes were characterized by average diameter, ζ-potential, encapsulation percentage, X-ray diffraction, and differential scanning calorimetry. Release studies in buffer (pH 7.4 or 5), plasma, and serum, as well as hydroxyapatite-affinity in vitro analysis were performed. Cytotoxicity was evaluated by MTT assay against the MDA-MB-231 cell line, and biodistribution was assessed in bone metastasis-bearing animals.Results: Liposomes presented suitable diameter (~170 nm), DOX encapsulation (~2 mg/mL), controlled release, and good plasma and serum stability. The existence of interactions between DOX and the lipid bilayer was proved through differential scanning calorimetry and small-angle X-ray scattering. DOX release was faster when the pH was in the range of a tumor than at physiological pH. The bone-targeted formulation showed a strong affinity for hydroxyapatite. The encapsulation of DOX did not interfere in its intrinsic cytotoxicity against the MDA-MB-231 cell line. Biodistribution studies demonstrated high affinity of this formulation for tumors and reduction of uptake in the heart.Conclusion: These results suggest that bone-targeted pH-sensitive liposomes containing DOX can be an interesting strategy for selectively delivering this drug into bone-tumor sites, increasing its activity, and reducing DOX-related toxicity. Keywords: hydroxyapatite-targeted formulations, bisphosphonates, pH-responsive nanostructures, bone-tumor treatment

To investigate the influence of siRNA-mediated down-regulation of CD147 on growth, proliferation and movement of human breast cancer cell line MDA-MB-231.The protein expression of CD147, MMP-2 and TIMP-2 of the MDA-MB-231 cells were analyzed by ABC. Lentiviral expression vector of CD147 gene was constructed and transfected into MDA-MB-231 cells. RT-PCR and Western blot were used to detect the mRNA and protein level changes of CD147 genes to identify the optimal time point, followed by detection of changes of mRNA and protein expression of MMP-2 and TIMP-2 genes. CCK-8 reagent method and cell scratch test were used to detect the proliferation and migration change of MDA-MB-231 cells. The nude mouse model of breast cancer by hypodermic injection with MDA-MB-231 cells was established to document the effect of CD147 siRNA on the tumor transplants.After transfection of lentiviral expression vector of CD147 gene, protein of CD147, MMP-2 and TIMP-2 were weakly or negative expressed, significantly weaker than those of control group (P0.01). After 72 hours of transfection, average down-regulation rate of CD147 and MMP-2 were 96.03% ± 0.84% and 96.03% ± 0.84%, respectively. Both CD147 mRNA and MMP-2 mRNA expression were down-regulated (P0.05), while TIMP-2 mRNA expression showed no significant deference (P0.05). No less than 2 days after transfection, cell growth of MDA-MB-231 cell line was found significantly inhibited (P0.05). After 24 hours of transection, average migration distance of MDA-MB-231 cell line and control group were (0.64 ± 0.12) mm and (4.69 ± 0.85) mm, respectively, which indicated a lower migrate speed. Down regulation of CD147 led to reduction of volume and mass of nude mouses. The growth of the carcinoma transplant was inhibited upon siRNA-mediated down-regulation of CD147 (P0.05), with an average tumor mass of (1.85 ± 0.98) g and both reduction of tumor size and tumor mass.CD147 may alter the MMP-2/TIMP-2 balance in MDA-MB-231 cells. CD147 gene silencing inhibits the proliferation and migration of MDA-MB-231 cells and the growth of carcinoma transplants in nude mice.

Oestrogen related receptor α participated in the regulation of oxidative metabolism and mitochondrial biogenesis, and was overexpressed in many cancers including triple-negative breast cancer. A set of new ERRα inverse agonists based on p-nitrobenzenesulfonamide template were discovered and compound 11 with high potent activity (IC50 = 0.80 μM) could significantly inhibit the transcription of ERRα-regulated target genes. By regulating the downstream signalling pathway, compound 11 could suppress the migration and invasion of the ER-negative MDA-MB-231 cell line. Furthermore, compound 11 demonstrated a significant growth suppression of breast cancer xenograft tumours in vivo (inhibition rate 23.58%). The docking results showed that compound 11 could form hydrogen bonds with Glu331 and Arg372 in addition to its hydrophobic interaction with ligand-binding domain. Our data implied that compound 11 represented a novel and effective ERRα inverse agonist, which had broad application prospects in the treatment of triple-negative breast cancer.

Background: Breast cancer is the second most common cancer in women worldwide. Developing drugs increase the radiosensitivity effect of tumoral tissue, while protecting normal tissues has gained much attention. Ginsenoside Rg3, one of the active components of ginseng, has been shown to possess various pharmacological effects and antiproliferation activity on cancer cell lines. In this study, we assessed the anti-cancer effect of co-treatment with ginsenoside 20(S)-Rg3 and curcumin on MDA-MB-231 breast cancer cells with and without radiotherapy. Methods: MTT assay was applied using different concentrations of ginsenoside 20(S)-Rg3 (0, 10, 80, 150 µmol/l) and curcumin (0, 10, 30, 50, 90 µg/mL). The inhibitory effect of co-treatment with these herbal drugs with and without 4 Gy radiotherapy on the MDA-MB-231 cell line was examined. Flow cytometry was applied to measure the effect of co-treatment of the drugs on radiation-induced apoptosis. The data were analyzed using ANOVA and Kruskal-Wallis tests. P values

Background Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer, with poor prognosis and limited treatment options. Hypoxia is a key hallmark of TNBC. Metabolic adaptation promotes progression of TNBC cells that are located within the hypoxic tumor regions. However, it is not well understood regarding the precise molecular mechanisms underlying the regulation of metabolic adaptions by hypoxia. Methods RNA sequencing was performed to analyze the gene expression profiles in MDA-MB-231 cell line (20% O2 and 1% O2). Expressions of Slc6a8, which encodes the creatine transporter protein, were detected in breast cancer cells and tissues by quantitative real-time PCR. Immunohistochemistry was performed to detect SLC6A8 protein abundances in tumor tissues. Clinicopathologic correlation and overall survival were evaluated by chi-square test and Kaplan-Meier analysis, respectively. Cell viability assay and flow cytometry analysis with Annexin V/PI double staining were performed to investigate the impact of SLC6A8-mediated uptake of creatine on viability of hypoxic TNBC cells. TNBC orthotopic mouse model was used to evaluate the effects of creatine in vivo. Results SLC6A8 was aberrantly upregulated in TNBC cells in hypoxia. SLC6A8 was drastically overexpressed in TNBC tissues and its level was tightly associated with advanced TNM stage, higher histological grade and worse overall survival of TNBC patients. We found that SLC6A8 was transcriptionally upregulated by p65/NF-κB and mediated accumulation of intracellular creatine in hypoxia. SLC6A8-mediated accumulation of creatine promoted survival and suppressed apoptosis via maintaining redox homeostasis in hypoxic TNBC cells. Furthermore, creatine was required to facilitate tumor growth in xenograft mouse models. Mechanistically, intracellular creatine bolstered cell antioxidant defense by reducing mitochondrial activity and oxygen consumption rates to reduce accumulation of intracellular reactive oxygen species, ultimately activating AKT-ERK signaling, the activation of which protected the viability of hypoxic TNBC cells via mediating the upregulation of Ki-67 and Bcl-2, and the downregulation of Bax and cleaved Caspase-3. Conclusions Our study indicates that SLC6A8-mediated creatine accumulation plays an important role in promoting TNBC progression, and may provide a potential therapeutic strategy option for treatment of SLC6A8 high expressed TNBC.

To construct a CXCR4 specific recombinant plasmid vector and study its inhibiting effect on invasion capacity in vitro of human breast cancer MDA-MB-231 cell line and its metastatic potential to the lung in nude mice.A CXCR4 specific recombinant plasmid vector was constructed and transfected into the cultured MDA-MB-231 cell line with lipofectamine 2000. RT-PCR and Western blot were used to detect the mRNA and protein expression of CXCR4, respectively. Invasion capability in vitro of the cells was evaluated by Boyden chamber. The cell proliferation capacity was detected by MTT method. The nude mouse model of lung metastasis was established by injection of MDA-MB-231 cells into the tail vein. The animals were sacrificed at 6 weeks after the tumor cells injection. Whole lung tissues were harvested, embedded in paraffin, sectioned serially, and the HE-stained paraffin sections were examined pathologically to evaluate the presence and number of metastatic tumors.The CXCR4 mRNA expression rate was 29.5% +/- 3.8% in the CXCR4-shRNA group, significantly lower than that of the control group (69.7% +/- 2.6%, P0.01) and mock-control group (67.8% +/- 3.5%, P0.01). The CXCR4 protein expression rate was 15.4% +/- 1.1% in the CXCR4-shRNA group, significantly lower than that of the control group (39.0% +/- 2.4%, P0.01) and mock-control group (35.9% +/- 3.9%, P0.01). Silencing of CXCR4 by shRNA lead to a significant decrease in breast cancer cell invasion and proliferation capacity in vitro. Furthermore, tumor cells with CXCR4 shRNA permanent transfcetion had a much lower lung metastatic potential in nude mice than control cells and mock control cells in vivo.CXCR4 shRNA can inhibit the expression of CXCR4 and decrease the invasion and lung metastatic potential of human breast cancer cells.

Hypoxia plays a vital role in tumor microenvironment by allowing development and maintenance of cancer cells thereby led to major hindrance for effective anticancer therapy and main reason for failure of most anticancer drugs. We herein investigated the therapeutic efficacy and molecular mechanism of action of aqua-(2-formylbenzoato) triphenyltin (IV) compound (OTC) in MDA-MB-231 cell line. Cobalt chloride induced hypoxic MDA-MB-231 cells treated with OTC were used to access cytotoxicity, ROS, cellular apoptosis, and cell cycle progression. Further, expression of HIF-1α and VEGF, as well as apoptotic proteins like p53, Bax, Bcl-2 and caspase 3 were assessed. The findings indicated that OTC is more effective towards CoCl

One of the best strategies to circumvent drug resistance is the employment of nanocarriers. For the current study, we have employed a nanoemulsion formulation of paclitaxel (PTX) to bypass drug resistance in the MDA-MB-231 cell line and impedance sensing biosensors to determine the exact time that PTX-NE induced apoptosis. Our MTT results demonstrated that PTX treatment could not reduce MDA-MB-231 cell viability to IC50 even after three days. However, the employment of the reagent TPGS (inhibitor of drug resistance) combined with paclitaxel could partially obviate PTX resistance. Next, the nanoemulsion form of PTX (PTX-NE) was fabricated employing the essential oil of the Satureja khuzestanica plant and was characterized using DLS and TEM methods. Our data showed that after 72 hours, PTX-NE at 250 nM concentration could induce a 50% reduction in cell viability. Moreover, annexin/PI and cell cycle analysis confirmed the apoptotic effect of PTX-NE on cancer cells. Lastly, we measured the impedance of MDA-MB-231 cells treated with the free and nanoemulsion forms of PTX. A significant decrease in the mean impedance of PTX-NE treated cells could be observed after 40 hours. To conclude, we have demonstrated here that PTX-NE could circumvent resistance and induce apoptosis in PTX-resistant breast cancer cells, which could be inferred from their impedance measurement.

Prodigiosin, a secondary metabolite red pigment produced by Serratia marcescens, has an interesting apoptotic efficacy against cancer cell lines with low or no toxicity on normal cells. HSP90α is known as a crucial and multimodal target in the treatment of TNBC. Our research attempts to assess the therapeutic potential of prodigiosin/PU-H71 combination on MDA-MB-231 cell line. The transcription and protein expression levels of different signalling pathways were assessed. Treatment of TNBC cells with both drugs resulted in a decrease of the number of adherent cells with apoptotic effects. Prodigiosin/PU-H71 combination increased the levels of caspases 3,8 and 9 and decreased the levels of mTOR expression. Additionally, there was a remarkable decrease of HSP90α transcription and expression levels upon treatment with combined therapy. Also, EGFR and VEGF expression levels decreased. This is the first study to show that prodigiosin/PU-H71 combination had potent cytotoxicity on MDA-MB-231 cells; proving to play a paramount role in interfering with key signalling pathways in TNBC. Interestingly, prodigiosin might be a potential anticancer agent to increase the sensitivity of TNBC cells to apoptosis. This study provides a new basis for upcoming studies to overcome drug resistance in TNBC cells.

Anti-angiogenesis is an important and promising strategy in cancer therapy. However, the current methods using anti-vascular endothelial growth factor A (VEGFA) antibodies or inhibitors targeting VEGFA receptors are not as efficient as expected partly due to their low efficiencies in blocking VEGFA signaling in vivo. Until now, there is still no method to effectively block VEGFA production in cancer cells from the very beginning, i.e., from the transcriptional level. Here, we aimed to find bioactive small molecules to block VEGFA transcription. Methods: We screened our natural compound pool containing 330 small molecules derived from Chinese traditional herbs for small molecules activating the expression of seryl-tRNA synthetase (SerRS), which is a newly identified potent transcriptional repressor of VEGFA, by a cell-based screening system in MDA-MB-231 cell line. The activities of the candidate molecules on regulating SerRS and VEGFA expression were first tested in breast cancer cells. We next investigated the antiangiogenic activity in vivo by testing the effects of candidate drugs on the vascular development in zebrafish and by matrigel plug angiogenesis assay in mice. We further examined the antitumor activities of candidate drugs in two triple-negative breast cancer (TNBC)-bearing mouse models. Furthermore, streptavidin-biotin affinity pull-down assay, coimmunoprecipitation assays, docking analysis and chromatin immunoprecipitation were performed to identify the direct targets of candidate drugs. Results: We identified emodin that could greatly increase SerRS expression in TNBC cells, consequently reducing VEGFA transcription. Emodin potently inhibited vascular development of zebrafish and blocked tumor angiogenesis in TNBC-bearing mice, greatly improving the survival. We also identified nuclear receptor corepressor 2 (NCOR2) to be the direct target of emodin. Once bound by emodin, NCOR2 got released from SerRS promoter, resulting in the activation of SerRS expression and eventually the suppression of VEGFA transcription. Conclusion: We discovered a herb-sourced small molecule emodin with the potential for the therapy of TNBC by targeting transcriptional regulators NCOR2 and SerRS to suppress VEGFA transcription and tumor angiogenesis.

The absence of receptors in triple-negative breast cancer limits therapeutic choices utilized in clinical management of the disease. Doxorubicin is an important member of therapeutic regimens that is hindered by emergence of resistance. The current work aim to investigate of therapeutic potential of single and combinations of siRNA molecules designed for silencing STAT 3, Notch-1, and β-catenin genes in wild type and doxorubicin resistant MDA-MB-231 triple negative breast cancer cell line. Doxorubicin resistant MDA-MB-231 cell line was developed and characterized for the expression of multidrug resistance-related genes, CD44/CD24 markers, inflammatory cytokines, and the expression of STAT 3, Notch-1, and β-catenin targeted genes. Further, the effect of single and combinations of siRNA on cell viability and chemosensitivity of both wild type MDA-MB-231 cells (MDA-MB-231/WT) and doxorubicin resistant MDA-MB-231 cells (MDA-MB-231/DR250) were assessed by MTT assay. The IC50 of doxorubicin was 10-folds higher in MDA-MB-231/DR250 resistant cells compared to MDA-MB-231/WT control cells, 1.53 ± 0.24 μM compared to 0.16 ± 0.02 μM, respectively. The expression of targeted genes was higher in resistant cells compared to control cells, 3.6 ± 0.16 folds increase in β-catenin, 2.7 ± 0.09 folds increase in Notch-1, and 1.8 ± 0.09 folds increase in STAT-3. Following treatment with siRNAs, there was a variable reduction in mRNA expression of each of the targeted genes compared to scrambled siRNA and a reduction in IC50 in both cell lines. The effect of a combination of three genes produced the largest reduction in IC50 in resistant cell line. Our study showed that the silencing of single and multiple genes involved in drug resistance and tumor progression by siRNA can enhance the chemosensitivity of cancer cells to conventional chemotherapy.

Breast cancer is one of the most common cancers and leading causes of death in the women worldwide. The evidence shows efficacy of apatinib against breast cancer. Accordingly, the present study was conducted to investigate the effect of apatinib on apoptosis, cell cycle, and Mitogen‑Activated Protein Kinase (MAPK) and nuclear factor-κB (NF-κB) signaling pathways in the breast cancer MDA-MB-231 cell line. The effects of apatinib on viability, morphology, tumor spheroid, cell cycle, migration, invasion, and apoptosis of MDA-MB-231 breast cancer cells were evaluated in vitro. In addition, expression of proteins involved in NF-κB and MAPK signaling pathways was evaluated using the western blotting analysis. Apatinib decreased viability, tumor spheroid, migration, and invasion of MDA-MB-231 cells. Furthermore, apatinib altered morphology and regulated cell cycle which followed by apoptosis induction in MDA-MB-231 cells. Apatinib decreased expression of p-p65 and p65 proteins in NF-κB signaling pathways and increased expression of p38, p-p38, JNK, and p-JNK in MAPK signaling pathways. The results suggested that apatinib can inhibit proliferation, migration and invasion of breast cancer cell line MDA-MB-231 through inducing apoptosis, cell cycle arrest, and regulating NF-κB and MAPK signaling pathways.

Deregulation of the basic helix‐loop‐helix family member e41 (BHLHE41) has been characterized as a marker of progression of several cancers. In this study, we aimed to explore the mechanism by which BHLHE41 regulates the invasion of breast cancer cells. BHLHE41 suppresses, whereas the silencing of BHLHE41 promotes tumour invasion of both MCF‐7 and MDA‐MB‐231 cells. Meanwhile, BHLHE41 down‐regulated the transcription and translation of SNAI1, SNAI2, VIM and CDH2, and up‐regulated those of CLDN1, CLDN4 and CDH1. Reporter assay indicated that silencing of BHLHE41 dramatically activated the MAPK/JNK signalling pathway in MCF‐7 cell line and the hypoxia signalling pathway in MDA‐MB‐231 cell line. Furthermore, silencing of BHLHE41 activated the MAPK/JNK signalling pathway by up‐regulating phosphorylated JNK and failed to affect the expression of HIF‐1 alpha in MCF‐7 cells. After blocking the MAPK/JNK signalling pathway by specific inhibitor SP600125, silencing of BHLHE41 failed to promote tumour cell invasion. These results suggest that BHLHE41 facilitates MCF‐7 cell invasion mainly via the activation of MAPK/JNK signalling pathway. In conclusion, although BHLHE41 suppresses tumour invasion in MCF‐7 and MDA‐MB‐231 cell lines, the specific regulatory mechanisms may be different.

Leucine zipper putative tumor suppressor 1 (LZTS1) is a tumor suppressor gene located on chromosome 8p22, and the expression is usually decreased in different types of cancers. Here we analyze the correlation between LZTS1 and paclitaxel sensitivity to breast cancer. LZTS1 expression was investigated in MDA-MB-231 cell line by reverse transcriptase-polymerase chain reaction(RT-PCR) and western blot. Cell cycle and apoptosis were detected using flow cytometry. Cell proliferation/viability assays to test drug sensitivity in breast cancer cell line. Human tumor xenograft models to measure chemo-sensitivity in LZTS1 over-expression tumor. The expression of LZTS1 was detected using immunohistochemistry in breast cancer, and the correlation between the LZTS1expression and the effect of chemotherapy was analyzed. In vitro cell proliferation assays revealed that LZTS1 expression was correlated with paclitaxel sensitivity in breast cancer cells. Cell cycle analysis and apoptosis experiments have demonstrated that LZTS1 could enhance the inhibitory effect of paclitaxel on the breast cancer cell cycle and the ability to induce apoptosis. Overexpression of LZTS1 could sensitize human breast carcinoma xenografts to paclitaxel. In addition, tumor with high LZTS1 expression was more sensitive to chemotherapy with paclitaxel in breast cancer. For the first time, we evaluated the relationship between LZTS1 expression and chemotherapy sensitivity using the Collagen gel droplet drug sensitivity test(CD-DST) in primary cell culture of breast cancer. LZTS1 may play an important role in improving the sensitivity of paclitaxel-based breast cancer chemotherapy.