MDA-MB231 Breast Cancer Cell Lines Research Articles

Nobiletin bioactivation in MDA-MB-468 breast cancer cells by cytochrome P450 CYP1 enzymes

Nobiletin is a fully methoxylated flavone that has demonstrated anticancer activity via multiple modes of action. In the present study, the metabolism and further antiproliferative activity of nobiletin was evaluated in the CYP1 expressing human breast cancer cell line MDA–MB–468 and the normal breast cell line MCF10A. Nobiletin was metabolized in MDA–MB–468 cells to a single-demethylated derivative assigned NP1. This metabolite was absent in MCF10A cells that did not express CYP1 enzymes. Nobiletin exhibited submicromolar IC50 (0.1 ± 0.04 μM) in MDA–MB–468 cells, whereas it was considerably less active in MCF10A cells (40 μM). In MDA–MB–468 cells that were coincubated with the CYP1 inhibitor acacetin, an approximately 300–fold increase was noted in the IC50 (30 ± 2.4 μM) of nobiletin. In the presence of the CYP1 inhibitor acacetin, the conversion of nobiletin to NP1 was significantly reduced in MDA–MB–468 cells. Furthermore, a significant increase was noted in the population of the cells at the G1 phase, following treatment with nobiletin (10 μM) for 24 h compared with the control cells treated with DMSO (0.1%) alone (55.9 ± 0.14 vs. 45.6 ± 1.96), whereas the cell cycle of MCF10A cells was not significantly altered under the same treatment conditions. Taken collectively, the results suggest that nobiletin is selectively bioactivated in MDA–MB–468 breast cancer cells via metabolism by the cytochrome P450 CYP1 family of enzymes.

The Protein Extract of Chlorella minutissima Inhibits The Expression of MMP-1, MMP-2 and MMP-9 in Cancer Cells through Upregulation of TIMP-3 and Down Regulation of c-Jun.

Objective Considering the bioactivities exhibited by microalgae, the effect of protein extract of Chlorella minutissimma (CP extract) was investigated on the expression of human matrix metalloproteinases-1 (MMP-1) in the breast cancer cell line MDA-MB231, and that of MMP-2 and -9 in hepatocellular cancer cell line HepG2 at different expression levels. The study aimed identification and analysis of inhibitory activity of microalgal components extracted from Chlorella minutissima against human MMPs. Materials and Methods In this experimental study, we analysed the effect of Chlorella extracts on MMP-1, -2, and -9 expression at various levels. Gelatin zymography was performed to study the inhibitory effect of Chlorella exracts on human gelatinases at the activity level, followed by western blotting to analyse the expression of all three MMPs at the protein level. The similar effect at the mRNA level along with the probable mechanism underlying inhibition of MMPs was assessed using real-time polymerase chain reaction (PCR). Results The results reveal that the treatment with CP extract decreased the mRNA expression of MMP-1, MMP-2, and MMP-9 by 0.26-, 0.29-, and 0.40-fold, respectively, at 20 μg/ml concentration as well as inhibited the activity of MMP-2 and MMP-9 by 37.56 and 42.64%, respectively, at 15 μg/ml concentration. Additionally, upregulated mRNA expression of tissue inhibitor of metalloproteinases-3 (TIMP-3) by 1.68-fold was seen in HepG2 cells at 20 μg/ml concentration treatment group. However, CP extract did not induce any change in the mRNA expression of the TIMP-1, -2 and -4 in HepG2 and TIMP-1, -2, -3 and -4 in MDA-MB231 cells. Activator protein-1 (AP-1)-dependent c-Jun-mediated transcriptional regulation of MMP-1, -2, and -9 was also studied to elucidate the appropriate mechanism involved in the inhibition of MMPs. ConclusionThe CP extract successfully inhibited MMP-1, -2, and -9 at different expression levels through TIMP-3 upregulation and c-Jun downregulation.

Cancer stem-like cells have cisplatin resistance and miR-93 regulate p21 expression in breast cancer

Aim: This study aims to examine the role of microRNAs (miRNAs) in regulating the expression of p21, a cyclin-dependent kinase inhibitor, and in inducing resistance to cisplatin, an anticancer drug. Methods: Human breast cancer cell line MDA-MB231 cells were separated into two subpopulations, cancer stem-like cells (CSCs) and cancer cells, based on the expression of cell surface antigens CD44 and CD24. Results: p21 protein expression was higher in CSCs than in cancer cells. Exposure of MDA-MB-231 cells to cisplatin increased p21 protein expression. However, p21 expression was significantly lower in cisplatin-treated CSCs than in cisplatin-treated cancer cells, suggesting that p21-dependent cell cycle suppression was lower in CSCs than in cancer cells. Moreover, caspase-3 activity was significantly lower in cisplatin-treated CSCs than in cisplatin-treated cancer cells, indicating that CSCs were more resistant to cisplatin-induced apoptosis than cancer cells. Treatment with miR-93 inhibitors increased p21 expression in CSCs, suggesting that miR-93 suppressed p21 expression. Conclusion: The results of the present study indicate that CSCs contribute to cisplatin resistance of MDA-MB231 cells and suggest that miR-93 inhibits the expression of p21, a factor involved in drug resistance.

TGFβ1 Promotes Breast Cancer Local Invasion and Liver Metastasis by Increasing the CD44high/CD24- Subpopulation.

Objective:Previous studies have shown that the transforming growth factor β1 pathway plays an important role in breast cancer metastasis to the liver. However, the mechanism of this metastasis has not been fully clarified. Cancer stem cells are essential for the initiation and propagation of tumor metastasis. The objective of our current study was to define the role of cancer stem cells in transforming growth factor β1-mediated breast cancer hepatic metastases.Method:Hematoxylin and eosin staining was used to assess the formation of breast cancer liver metastases and local invasion. Cancer stem cells surface markers (CD44, CD24, and Epithelial cell adhesion molecule [EpCAM]), luminal/mesenchymal markers (keratin8 and alpha smooth muscle actin), and proliferation markers (Ki-67 and cyclinD1) were detected by immunohistochemistry assays. Flow cytometry was used to evaluate the effect of transforming growth factor β1 on the CD44+/CD24− cancer stem cell population. Quantitative real-time polymerase chain reaction was employed to assess the gene expression of the stem cell self-renewal markers nanog, pou5f1 (coding for Oct4), and sox2.Results:Transforming growth factor β1 increased the formation of liver metastases by the MDA-MB231 (MDA) breast cancer cell line but did not affect the liver metastasis of CD44+/CD24+ noncancer stem cells. Transforming growth factor β1 treatment did not significantly affect tumor proliferation in vitro or in vivo. Transforming growth factor β1 promoted mammary tumor local invasion. Furthermore, the CD44high/CD24− cancer stem cell population was also significantly increased by transforming growth factor β1 treatment. Besides, the gene expression of the stem cell self-renewal markers (nanog, pou5f1, and sox2) and another stem cell surface marker (EpCAM) was increased by transforming growth factor β1 treatment. Finally, clusters of CD44-positive breast cancer cells were observed in the livers of mice from the control and transforming growth factor β1 pretreatment groups.Conclusion:Our results indicate that transforming growth factor β1 increases the local invasive capacity and liver metastasis of breast cancer cells by inducing the CD44high/CD24− cancer stem cell population.

Abstract 51: The eukaryotic translation initiation factor 4H regulates proliferation, migration, and invasion in cancer cells

Abstract Background: Dysregulated translation during protein synthesis is a hallmark of multiple human cancers. However, the precise mechanisms remain to be understood. Protein translation of oncogenic mRNAs is highly upregulated in cancer cells and these cells are very sensitive to therapeutic strategies/agents targeting translation inhibition. In this study we investigated the role of translation initiation factor eIF4H in proliferation and survival of cancer cells. Methods: We selected the breast cancer cell line MDA-MB 231 and the CML cell line K562 for our study. We silenced eIF4H by shRNA and cell proliferation were analyzed by MTT assay and flowcytometry. Expression of antiapoptotic and proproliferative proteins were analyzed by Western blotting and for analysis of mRNA expression real-time PCR was used. Effect of eIF4H silencing on cell migration and invasion was analyzed by migration and invasion assays, respectively. Results: Using 2D Gel based proteomics we targeted the translational machinery in chronic myeloid leukemia cell line K562 and identified eIF4H as a critical regulator of carcinogenesis. The eIF4H expression was found to be overexpressed in a variety of cancer cell line vis-à-vis the normal nontransformed cells. Similarly, the real-time PCR analysis showed eIF4H overexpression in chronic myeloid leukemia clinical samples compared to that of the healthy controls. The pharmacologic inhibition of eIF4H induced downregulation of its regulatory proteins cMYC, cyclin D1, and antiapoptotic proteins in breast cancer cell line MDAMB-231 and CML cell line K562 cells. The genomic inhibition of eIF4H decreased cell migration and invasion in vitro in MDA-MB 231 cell line and it also inhibits proliferation of both cell lines. Furthermore, the p65-dependent transcriptional activation of eIF4H was observed to be associated with this process. Conclusion: Our results demonstrate that eIF4H plays an important role in the proliferation, migration, and invasion of cancer cells. Silencing of eIF4H markedly decreased expression of antiapoptotic and proproliferative proteins. Collectively, our findings suggest that eIF4H may have translational relevance as a therapeutic target in cancer therapy. Citation Format: Manohar Singh, Rachana Trivedi, Durga Prasad Mishra. The eukaryotic translation initiation factor 4H regulates proliferation, migration, and invasion in cancer cells [abstract]. In: Proceedings of the Second AACR Conference on Hematologic Malignancies: Translating Discoveries to Novel Therapies; May 6-9, 2017; Boston, MA. Philadelphia (PA): AACR; Clin Cancer Res 2017;23(24_Suppl):Abstract nr 51.

Cytotoxicity of Benzyl Isoquinolinic Alkaloids, Palmatine and Corydaline on MCF-7 and MDAMB231 Breast Cancer Cell Lines

Cytotoxicity of Benzyl Isoquinolinic Alkaloids, Palmatine and Corydaline on MCF-7 and MDAMB231 Breast Cancer Cell Lines

HIV-1 matrix protein p17 and its variants promote human triple negative breast cancer cell aggressiveness

BackgroundThe introduction of cART has changed the morbidity and mortality patterns affecting HIV-infected (HIV+) individuals. The risk of breast cancer in HIV+ patients has now approached the general population risk. However, breast cancer has a more aggressive clinical course and poorer outcome in HIV+ patients than in general population, without correlation with the CD4 or virus particles count. These findings suggest a likely influence of HIV-1 proteins on breast cancer aggressiveness and progression. The HIV-1 matrix protein (p17) is expressed in different tissues and organs of successfully cART-treated patients and promotes migration of different cells. Variants of p17 (vp17s), characterized by mutations and amino acid insertions, differently from the prototype p17 (refp17), also promote B-cell proliferation and transformation.MethodsWound-healing assay, matrigel-based invasion assay, and anchorage-independent proliferation assay were employed to compare the biological activity exerted by refp17 and three different vp17s on the triple-negative human breast cancer cell line MDA-MB 231. Intracellular signaling was investigated by western blot analysis.ResultsMotility and invasiveness increased in cells treated with both refp17 and vp17s compared to untreated cells. The effects of the viral proteins were mediated by binding to the chemokine receptor CXCR2 and activation of the ERK1/2 signaling pathway. However, vp17s promoted MDA-MB 231 cell growth and proliferation in contrast to refp17-treated or not treated cells.ConclusionsIn the context of the emerging role of the microenvironment in promoting and supporting cancer cell growth and metastatic spreading, here we provide the first evidence that exogenous p17 may play a crucial role in sustaining breast cancer cell migration and invasiveness, whereas some p17 variants may also be involved in cancer cell growth and proliferation.

Chemotherapy treatment induces an increase of autophagy in the luminal breast cancer cell MCF7, but not in the triple-negative MDA-MB231

Autophagy is one of the chemotherapy resistance mechanisms in breast cancer. The aim of this study was to determine the level of recruitment of the autophagy pathway in the triple-negative breast cancer (TNBC) cell line MDA-MB231 compared with that in the control luminal breast cancer cell line MCF7 before and after treatment with chemotherapy drugs. Furthermore, we investigated the relationship between autophagy and EGFR, MUC1 and IL17-receptors as activators of autophagy. Immunohistochemistry was performed in cell culture blocks using LC3b, MUC1-C, EGFR, IL17A, IL17-RA and IL17-RB antibodies. We found that the basal autophagy level in MDA-MB231 was high, whereas it was low in MCF7. However, in contrast to MDA-MB231, the autophagy level was increased in MCF7 upon treatment with chemotherapy agents. Interestingly, we observed that the expression levels of MUC1-C, EGFR, IL17-RA, and IL17-RB were not modified by the same treatments. Furthermore, the chemotherapy treatments did not increase autophagy in TNBC cells without affecting the expression levels of MUC1-C, EGFR, IL17-RA or IL17-RB.

Analysis of the microvascular morphology and hemodynamics of breast cancer in mice using SPring-8 synchrotron radiation microangiography.

Tumor vasculature is characterized by morphological and functional abnormalities. However, analysis of the dynamics in blood flow is still challenging because of limited spatial and temporal resolution. Synchrotron radiation (SR) microangiography above the K-edge of the iodine contrast agent can provide high-contrast imaging of microvessels in time orders of milliseconds. In this study, mice bearing the human breast cancer cell lines MDAMB231 and NOTCH4 overexpression in MDAMB231 (MDAMB231NOTCH4+) and normal mice were assessed using SR microangiography. NOTCH is transmembrane protein that has crucial roles for vasculogenesis, angiogenesis and tumorigenesis, and NOTCH4 is considered to be a cause of high-flow arteriovenous shunting. A subgroup of mice received intravenous eribulin treatment, which is known to improve intratumor core circulation (MDAMB231_eribulin). Microvessel branches from approximately 200 µm to less than 20 µm in diameter were observed within the same visual field. The mean transition time (MTT) was measured as a dynamic parameter and quantitative analysis was performed. MTT in MDAMB231 was longer than that in normal tissue, and MDAMB231NOTCH4+ showed shorter MTT [5.0 ± 1.4 s, 3.6 ± 1.0 s and 3.6 ± 1.1 s (mean ± standard deviation), respectively]. After treatment, average MTT was correlated to tumor volume (r = 0.999) in MDAMB231_eribulin, while in contrast there was no correlation in MDAMB231 (r = -0.026). These changes in MTT profile are considered to be driven by the modulation of intratumoral circulation dynamics. These results demonstrate that a SR microangiography approach enables quantitative analysis of morphological and dynamic characteristics of tumor vasculature in vivo. Further studies will reveal new findings concerning vessel function in tumors.

Effects of siRNAs targeting CD97 immune epitopes on biological behavior in breast cancer cell line MDA-MB231

To investigate the effects of siRNAs targeting CD97 immune epitopes on proliferation, infiltration, apoptosis and cell cycle of breast cancer cells. siRNA sequences targeting CD97EGF and CD97Stalk immune epitopes were designed according to Gene Bank NM_001025160.2 with smart siCatchTM siRNA design software. CD97siRNAs were transfected into MDA-MB231 cells in which CD97 was highly expressed. Highest sensitive CD97EGF and CD97Stalk siRNA were screened by Western blotting. Inverted microscope was used to observe the growth of CD97siRNAs-transfected MDA-MB231 cells; the proliferation activity of MDA-MB231 cells was detected by MTT method; the wound healing assay and Transwell migration test were performed to examine the migration and infiltration ability of CD97EGF and CD97Stalk siRNA-transfected MDA-MB231 cells; the effects of CD97EGF siRNA and CD97Stalk siRNA on cell apoptosis and cell cycle of MDA-MB231 cells were detected by TUNEL and flow cytometry. The growth and proliferation activity of CD97siRNAs-transfected MDA-MB231 cells were significantly lower than those in the control groups, and such differences were more significant in CD97Stalk siRNA-transfected group (all P<0.05); scratch test showed that the wound healing rate was lower in CD97siRNAs-transfected groups, especially in CD97Stalk siRNA-transfected group (all P<0.05); Transwell migration showed that the number of MDA-MB231 cells crossing through chambers were less in CD97siRNAs-transfected groups, especially in CD97Stalk siRNA-transfected group (all P<0.05); no significant difference in cell apoptosis was observed between CD97siRNAs-transfected groups and control groups; cell cycle detection showed that CD97siRNAs-transfected groups had less cells in G0/G1 phase and more cells in S phase compared with the control groups, and such effect on cell cycle was more marked in CD97Stalk siRNA-transfected group (all P<0.05). CD97 plays an important role in the cell growth, proliferation, migration and invasion of breast cancer MDA-MB231 cells, and compared with CD97EGF, CD97Stalk may have more effective inhibitory effects on cellular malignant behaviors.

Abstract 4: Inhibitory effects of aprotinin on survival and local invasion of human breast cancer cell lines

Abstract Background: Aprotinin is a nonspecific serine protease inhibitor, which can inhibit kallikrein and many downstream extracellular matrix degrading enzymes. In this study, we assessed inhibitory effects of aprotinin on local invasion of human breast cancer cell lines. Methods: We assessed effects of aprotinin on local invasion and survival of human breast cancer cell lines MDA-MB231 and SK-BR-3 in vitro. CHEMICON Cell Invasion Assay Kit was used to assess local invasion of tumoral cells. MTT assay was used to determine the anti-proliferative activity of aprotinin on different cancer cell lines. Mean optical densities of duplicate experiments were calculated for both assays. HDF-1 human fibroblast cell line was used as control normal cell. In addition, local invasion and survival of tumor cell lines treated with aprotinin were compared with untreated experiments. Results: Cancer cell lines showed more invasion compared to HDF-1. Aprotinin significantly decreased the invasiveness of MDA-MB231 in concentration of 1 TIU/ml, 1.3 TIU/ml, and 1.7 TIU/ml in comparison with untreated group (ANOVA P &amp;lt;0.001). Treatment of SK-BR-3 with 1.3 TIU/ml aprotinin trended towards reduction of invasion optical density (P = 0.06). Treatment with different concentrations of aprotinin significantly decreased the surviving fraction and significantly inhibited the growth of all cell lines tested in this study (ANOVA P &amp;lt;0.001). Conclusion: Aprotinin inhibited the survival and local invasion of human breast cancer cell lines MDA-MB231 and SK-BR-3. Although the growth inhibitory effect was significant in both cell lines, inhibition of local invasion was more pronounced in case of MDA-MB231. Future molecular studies could shed further lights on mechanisms underlying anti-neoplastic effects of aprotinin and its potential therapeutic effects. Citation Format: Saeed Soleyman-Jahi, Kazem Zendehdel, Fatemeh Sadeghi, Ziba Afshari, Tahereh Barati, Samad Mohammadnezhad, Sevil Ghasemi, Saeed Amanpour. Inhibitory effects of aprotinin on survival and local invasion of human breast cancer cell lines [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4. doi:10.1158/1538-7445.AM2017-4

Preparation and nanoformulation of new quinolone scaffold-based anticancer agents: Enhancing solubility for better cellular delivery

A new series of 5,7-dibromoquinoline scaffold-based derivatives with varied flexibility substituents at position 8 of the ring system has been synthesized as potential anticancer agents. The new compounds were evaluated for their in vitro antiproliferative activity versus the human breast cancer cell lines MCF-7 and MDA-MB231. Generally, both cell lines were responsive to the cytotoxic effect of the synthesized analogues. Compounds 4a, 5c and 7b were chosen for nanoformulation studies to assess the effect of enhancing their solubility profile on their cytotoxic ability. Indeed, the pluronic nanomicelles of the three formulated derivatives showed an observable significant increase in their cytotoxic efficacy demonstrating a positive impact of the used nanoformulations on the delivery of the active compounds to their cellular biological targets.

U94 of human herpesvirus 6 down-modulates Src, promotes a partial mesenchymal-to-epithelial transition and inhibits tumor cell growth, invasion and metastasis.

U94, the latency gene of human herpesvirus 6, was found to inhibit migration, invasion and proliferation of vascular endothelial cells (ECs). Because of its potent anti-migratory activity on ECs, we tested the capability of U94 to interfere with the individual steps of the metastatic cascade. We examined the U94 biological activity on the human breast cancer cell line MDA-MB 231, as a model of highly aggressive cancer cell. Here we show that the expression of U94 delivered by an HSV-1-based amplicon promoted down-modulation of Src and downstream molecules linked to cell motility and proliferation. Indeed, U94 expression strongly inhibited cell migration, invasiveness and clonogenicity. We investigated the effects of U94 in a three-dimensional rotary cell-culture system and observed the ability of U94 to modify tumor cell morphology by inducing a partial mesenchymal-to-epithelial transition. In fact, despite U94 did not induce any expression of the epithelial marker E-cadherin, it down-modulated different mesenchymal markers as β-catenin, Vimentin, TWIST, Snail1, and MMP2. In vivo data on the tumorigenicity of MDA-MB 231 displayed the capability of U94 to control tumor growth, invasiveness and metastasis, as well as tumor-driven angiogenesis. The antitumor U94 activity was also confirmed on the human cervical cancer cell line HeLa. The ability of U94 to inhibit cell growth, invasion and metastasis opens the way to a promising field of research aimed to develop new therapeutic approaches for treating tumor and cancer metastasis.

Development of Murine Model for Breast Cancer Metastasis to Bone

Breast cancer is the second most common diagnosed cancer. 70% of breast cancers metastasize to the bone. This metastasis is more serious than the original tumor. The present study deals with the generation of animal (rat) model for breast cancer metastasis to bone by insertion of human breast cancer cell line MDA-MB 231. The cell line MDA-MB 231 was administered in the immunosupressed rat femur bone and tumor formation was observed for two months. Blood parameters viz; SGOT, SGPT, ALP, TRAP and calcium and antioxidant enzymes (catalase, SOD, GSH, GSSG, GST, MDA and GPX) in liver tissue were studied after one month and two months of insertion. In our study we observed increase in the antioxidant liver enzyme levels i.e. Catalase, SOD, GSH, GSH and MDA, and SGOT, ALP, TRAP and calcium levels also were increased in serum. Increased levels of antioxidant enzymes are indicative of increases Reactive oxygen species (oxidative stress) are involved in initiation, promotion and progression of carcinogenesis. Further, bone histopathology results indicate necrotic bone in experimental rats, which suggests osteolytic bone metastasis. This developed model for breast cancer metastasisto bone is cost effective and gives insight into the metastatic colonization, in which initially formed micrometastasis succeed in colonizing the marrow and generating osteolytic metastasis.

Abstract P6-01-05: Novel cytotoxic RNA aptamers that distinguish between metastasis-prone and indolent breast and prostate cancers

Abstract Background: Prostate and breast cancers are, respectively, the most common malignancies diagnosed in men and women worldwide. These cancers develop in different organs but have significant biological similarities: both are typically hormone-dependent, and both require early detection and treatment, as metastatic disease is incurable. At the same time, early stage tumors are often over-treated. Better markers for tumor aggressiveness would help to optimize treatment strategies in both breast and prostate cancer. Objective: Develop high affinity nucleic acid oligomers (aptamers) that can distinguish between indolent tumors that will remain organ-confined and those with heightened potential to metastasize. Methods: We performed subtractive RNA Cell-SELEX to select for surface ligands specific to aggressive tumors, using as a positive selector the highly metastasis-competent LN3 subclone of prostate cancer cell line LNCaP, and as negative selectors parental LNCaP and a non-metastasizing subclone, Pro5. . The RNA aptamer pool was PCR amplified from a 40-mer random nucleotide cDNA library with appropriate flanking sequences, and transcribed in vitro. After 11 SELEX cycles, aptamer pools from cycles 0, 4, 9, and 11 were subjected to high-throughput sequencing. Eight aptamers, representing 4 sequence families, were chosen for further study. Representative relevant and irrelevant aptamers were labeled with Cy3 and used to stain LNCaP-LN3 and LNCaP-Pro5 in culture and as xenografts in NOD-SCID-gamma mice. Additional cell and tumor lines from both breast and prostate cancer were used for validation. Results: Two aptamers bound avidly to the surface of the aggressive LNCaP-LN3 subclone, both in culture and in fixed xenograft tumors, but not to the indolent Pro5 subclone. Aptamer binding led to rapid and specific cytotoxicity in vitro but had no effect on other cell lines to which the aptamer did not bind. The same aptamers showed similar high specificity for multiple other metastasis-competent cancer cells, including the prostate adenocarcinoma PC-3 and PC-3ML subclones, breast cancer cell lines MDA-MB436 and MDA-MB231, and the primary dissociated breast tumor DT28 , while exhibiting no detectable binding to the non-metastasizing MCF-7 breast cancer cell line and DT22 primary dissociated breast tumor cells, and the non-tumorigenic prostate epithelial cell line RPWE-1. Conclusion: We identified RNA aptamers that specifically bind to metastasis-prone prostate cancer and breast cancer cell surface targets, and exert cell-specific toxicity dependent upon aptamer binding. While the target(s) remain to be identified, we propose that these aptamers may discriminate between progressive and indolent breast and prostate cancers, and may have substantial promise as anticancer agents either alone or suitably liganded to toxic moieties. Citation Format: Bishopric NH, Speransky S, Serafini P, De la Fuente AC, Bicciato S, El-Ashry D, Lippman ME. Novel cytotoxic RNA aptamers that distinguish between metastasis-prone and indolent breast and prostate cancers [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P6-01-05.

Antimicrobial and anticancer activities of porous chitosan-alginate biosynthesized silver nanoparticles

The main aim of this study was to obtain porous antimicrobial composites consisting of chitosan, alginate, and biosynthesized silver nanoparticles (AgNPs). Chitosan and alginate were used owing to their pore-forming capacity, while AgNPs were used for their antimicrobial property. The developed porous composites of chitosan-alginate-AgNPs were characterized using Fourier transform infrared spectroscopy (FT-IR), ultraviolet-visible spectroscopy, X-ray diffraction (XRD) analysis, and scanning electron microscopy (SEM). The FT-IR results revealed the presence of a strong chemical interaction between chitosan and alginate due to polyelectrolyte complex; whereas, the XRD results confirmed the presence of AgNPs in the composites. The dispersion of AgNPs in the porous membrane was uniform with a pore size of 50–500μm. Antimicrobial activity of the composites was checked with Escherichia coli and Staphylococcus aureus. The developed composites resulted in the formation of a zone of inhibition of 11±1mm for the Escherichia coli, and 10±1mm for Staphylococcus aureus. The bacterial filtration efficiency of chitosan-alginate-AgNPs was 1.5-times higher than that of the chitosan-alginate composite. The breast cancer cell line MDA-MB–231 was used to test the anticancer activity of the composites. The IC50 value of chitosan-alginate-AgNPs on MDA-MB–231 was 4.6mg. The developed chitosan-alginate-AgNPs composite showed a huge potential for its applications in antimicrobial filtration and cancer treatment.

Silencing HS6ST3 inhibits growth and progression of breast cancer cells through suppressing IGF1R and inducing XAF1

Heparan sulfate 6-O-sulfation is biologically edited by 6-O-sulfotransferases (HS6STs) within heparan sulfate chains. Three isoforms of HS6ST have been identified. These enzymes are found to be differentially expressed in a variety of tissues. Recently, several studies have shown that dysregulation of 6-O-sulfotransferases could be involved in tumorigenesis of several cancers. This study aimed to analyze the expression and function of HS6ST3 in breast cancer. HS6ST3 was found up-regulated in T47D, MCF7 and MDA-MB231 breast cancer cell lines. HS6ST3 was then silenced in T47D and MCF7 using siRNA. Silencing HS6ST3 diminished tumor cell growth, migration and invasion, but enhanced cell adhesion and apoptosis in breast cancer. Gene microarray analysis revealed that silencing HS6ST3 significantly changed the expression of IGF1R and XAF1 in breast cancer cells. Further functional studies showed that the cellular processes were mediated by IGF1R and XAF1 after silencing HS6ST3 in breast cancer cells. Together these results indicate that HS6ST3 might be involved in the tumorigenesis of breast cancer and it could be a promising target in breast cancer therapy.

Zoledronic Acid Inhibits the Motility of Cancer Stem-like Cells from the Human Breast Cancer Cell Line MDA-MB 231.

Various effects on tumor cells have been described for zoledronic acid (ZOL). However, only limited data exist regarding its influence on the motility of tumor cells. Since migration of tumor stem cells is a decisive step in metastasis, we examined whether ZOL reduces their motility. We investigated the effects of ZOL on stem-like progenitor cells obtained via the formation of spheroids from the human breast cancer cell line MDA-MB 231. Stem cell properties were verified by measurement of high CD44 expression and absence of CD24 expression. Motility was explored by time-resolved videography, protein expression by western blotting. ZOL strongly reduced the migration of stem-like progenitor cells. Cellular velocity was reduced by 61% following exposure to 1 μM ZOL and by 82% after exposure to 10 μM ZOL. Accumulated distance traveled by the cells was reduced by 60% and 79% after exposure to 1 μM and 10 μM ZOL, respectively. The remaining cellular motility led to very little change in distance, with cellular activity appearing more as "stepping on the spot". The reduced motility might be due to reduced phosphorylation of focal adhesion kinase (FAK), an important enzyme in cellular migration. ZOL reduces the motility and cellular velocity of breast cancer cells in vitro. The reduced mobility might slow down or even stop metastasis, which is a known result of adjuvant ZOL therapy in breast cancer patients. In vivo studies are warranted to evaluate the impact of the reduced motility on the metastatic cascade.

Dose Effect of Rhenium (I)-diselenoether as Anticancer Drug in Resistant Breast Tumor-bearing Mice After Repeated Administrations.

Rhenium (I)-diselenoether has shown promising antiproliferative efficacy in both in vitro and in vivo models. However, the maximal tolerated dose and dose-effect relationships have not been fully addressed for this compound. Here, we evaluated the tolerance and efficacy of three dose-levels (namely 10, 40 and 100 mg/kg) intraperitoneally administered daily over 28 days in mice bearing the resistant MDA-MB231 breast cancer cell line. The upper dose was found to be toxic and was reduced to 60 mg/kg. The 10 mg/kg dose well tolerated, whereas 40 mg/kg was associated with 10% mortality (LD10). Both 10 and 40 mg/kg dosing achieved a significantly similar regression of tumor growth compared with untreated animals. This study suggests that 10 mg/kg daily is the recommended dose for rhenium (I) diselenoether.

Extracellular matrix 1 (ECM1) regulates the actin cytoskeletal architecture of aggressive breast cancer cells in part via S100A4 and Rho-family GTPases.

ECM1 overexpression is an independent predictor of poor prognosis in primary breast carcinomas, however the mechanisms by which ECM1 affects tumor progression have not been completely elucidated. ECM1 was silenced in the triple-negative breast cancer cell lines Hs578T and MDAMB231 using siRNA and the cells were evaluated for changes in morphology, migration, invasion and adhesion. Actin cytoskeleton alterations were evaluated by fluorescent staining and levels of activated Rho GTPases by pull down assays. ECM1 downregulation led to significantly diminished cell migration (p=0.0005 for Hs578T and p=0.02 for MDAMB231) and cell adhesion (p<0.001 for Hs578T and p=0.01 for MDAMB231). Cell invasion (matrigel) was reduced only in the Hs578T cells (p<0.01). Silencing decreased the expression of the prometastatic molecules S100A4 and TGFβR2 in both cell lines and CD44 in Hs578T cells. ECM1-silenced cells also exhibited alterations in cell shape and showed bundles of F-actin across the cell (stress fibers) whereas NT-siRNA treated cells showed peripheral membrane ruffling. Downregulation of ECM1 was also associated with an increased F/G actin ratio, when compared to the cells transfected with NT siRNA (p<0.001 for Hs578T and p<0.00035 for MDAMB231) and a concomitant decline of activated Rho A in the Hs578T cells. Re-expression of S100A4 in ECM1-silenced cells rescued the phenotype in the Hs578T cells but not the MDAMB231 cells. We conclude that ECM1 is a key player in the metastatic process and regulates the actin cytoskeletal architecture of aggressive breast cancer cells at least in part via alterations in S100A4 and Rho A.