Activity In MCF-7 Research Articles

Abstract 2984: Plumbagin induces p53-dependent apoptosis via generation of reactive oxygen species in human cancer cells

Abstract Plumbagin [5-hydroxy-2-methyl-1,4-naphthaquinone], a major constituent derived from Drosera and Plumbago, displays antitumor activity both in vitro and animal models, but the molecular mechanisms of p53-mediated antitumor effects have not been clearly explored. The aim of this study is to determine the anticancer effects of plumbagin on MCF-7 (wild type p53) or Ishikawa (p53-mutant type) cells. We compared the cytotoxicity, cell cycle regulation, apoptotic cell death, and generation of intracellular reactive oxygen species (ROS) in these cancer cells. Plumbagin inhibits the growth of Ishikawa (endometrial cancer cells) and SKOV-3 cells, particularly MCF-7 cells. Plumbagin significantly increased the expression of p53 and reduced Murine Double Minute 2 (MDM2) in the MCF-7 cells. Plumbagin up-regulated the expression of p21(CIP1/WAF1) causing cell cycle arrest in the G2/M-phase by down-regulating cyclin B1 and Cdc2 in MCF-7 as well as Ishikawa cells. Plumbagin altered the ratio of Bax/Bcl-2 and cytochrome c released resulting apoptotic cell death in MCF-7 cells. Furthermore, plumbagin dramatically increased the intracellular ROS level, and pretreatment with the ROS scavenger, N-acetyl cysteine (NAC), protected against growth inhibition by plumbagin, suggesting that ROS play a pivotal role in the antitumor activity in MCF-7 cells. In mice bearing the MCF-7 cell xenografts, plumbagin significantly reduced the tumor growth and weight, without apparent side effects. In conclusion, plumbagin exerted anticancer activity in MCF-7 by generation of intracellular ROS that causes induction of apoptosis via Bcl-2/Bax pathways as well as cell cycle arrest. KEYWORDS: Plumbagin; breast cancer; apoptosis; p53, reactive oxygen species Citation Format: Umasankar De, Amit Kundu, Eunbin Kim, Jonghwan Kwack, Hyungsik Kim. Plumbagin induces p53-dependent apoptosis via generation of reactive oxygen species in human cancer cells. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2984.

Abstract 4803: A novel class of phenylacrylonitrile-based small molecules selectively induce double-strand DNA damage in breast cancer cells

Abstract We have discovered a class of phenylacrylonitrile-based small molecules that selectively target breast cancer cell lines while having little to no effect on normal breast cancer cells or on cell lines derived from other tumour types including colon, ovarian, lung, skin, prostate and pancreatic carcinomas, neuroblastoma and glioblastoma. Indeed these molecules show more than 200-fold selectivity towards breast cancer cells compared with other tumour types, while maintaining nM potency, as determined by the MTT growth inhibition (GI50) assay with GI50 values of 0.2-2.0μM (72h exposure). Moreover, the sensitive breast cancer cell lines represent tumour types from the four main breast cancer classifications including ER+ luminal A (MCF-7, T47-D and ZR-75-1 cells), ER+ luminal B (BT-474), HER2+ (SKBR-3), and most importantly the Basal (triple negative MDA-MB-468 and BT20) classification which traditionally carries a very poor prognosis. Our novel class of molecules also retain activity in MCF-7/VP16 cells (GI50 0.2μM) which overexpresses the drug resistance ABCC1 gene. Only one breast cancer cell line has shown insensitivity, MDA-MB-231 (Basal triple negative), which unlike all of the other breast cell types has amplifying mutations in KRas and BRaf activity, a genotype found in less than 5% of breast cancer tumours. Furthermore, our novel compounds induce minimal effects on the growth of normal MCF10A breast cells. Analysis of our most sensitive breast cancer cell line (MDA-MB-468) shows a significant increase in gammaH2AX within 12h of exposure to our lead phenylacrylonitrile molecule, indicative of DNA double strand breakage. This response is concomitant with an increase in the phosphorylation of the cell cycle check point activator CHK2. Cell cycle analysis shows an increase in the proportion of cells in the S-phase of the cell cycle within 24h of exposure, concomitant with a decrease in the proportion of cells in the G1-phase, and preceding an increase in the sub-G1 cell death population. The ability to specifically target breast tumours, while having little or no effect on normal breast cells, or other tumour types is a unique finding. Elucidating the mechanism controlling this phenomenon is now the focus of our research efforts. Citation Format: Jennette A. Sakoff, Jayne Gilbert, Geoff De Iuliis, Adam McCluskey. A novel class of phenylacrylonitrile-based small molecules selectively induce double-strand DNA damage in breast cancer cells. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4803.

Dioscin strengthens the efficiency of adriamycin in MCF-7 and MCF-7/ADR cells through autophagy induction: More than just down-regulation of MDR1.

The purpose of present study was to investigate the effect of dioscin on activity of adriamycin (ADR) in ADR-sensitive (MCF-7) and ADR-resistant (MCF-7/ADR) human breast cancer cells and to clarify the molecular mechanisms involved. Antiproliferation effect of ADR was enhanced by dioscin in MCF-7 and MCF-7/ADR cells. Dioscin significantly inhibited MDR1 mRNA and protein expression and MDR1 promoter and nuclear factor κ-B (NF-κB) activity in MCF-7/ADR cells. Additionally, inhibitor κB-α (IκB-α) degradation was inhibited by dioscin. Moreover, dioscin induced the formation of vacuoles in the cytoplasm and protein level of LC3-II in MCF-7 and MCF-7/ADR cells. Autophagy inhibitor 3-MA abolished the effect of dioscin on ADR cytotoxicity. Dioscin inhibited phosphorylation of PI3K and Akt, resulting in upregulation of LC3-II expression. In conclusion, dioscin increased ADR chemosensitivity by down-regulating MDR1 expression through NF-κB signaling inhibition in MCF-7/ADR cells. Autophagy was induced by dioscin to ameliorate the cytotoxicity of ADR via inhibition of the PI3K/AKT pathways in MCF-7 and MCF-7/ADR cells. These findings provide evidence in support of further investigation into the clinical application of dioscin as a chemotherapy adjuvant.

Design, synthesis, and evaluation of water-soluble morpholino-decorated paclitaxel prodrugs with remarkably decreased toxicity

Novel water-soluble paclitaxel prodrugs were designed and synthesized by introducing morpholino groups through different linkers. These derivatives showed 400–20,000-times greater water solubility than paclitaxel as well as comparable activity in MCF-7 and HeLa cell lines. The prodrug PM4 was tested in the S-180 tumor mouse model, with paclitaxel as the positive control. The results showed that PM4 had comparable antitumor activity as paclitaxel, with tumor inhibition of 54% versus 56%, and remarkably decreased toxicity. The survival rate of treated mice was 8/8 in the PM4 group, compared to 3/8 in the paclitaxel group.

Reversal of efflux of an anticancer drug in human drug-resistant breast cancer cells by inhibition of protein kinase Cα (PKCα) activity.

P-glycoprotein (Pgp) is a 170-kDa transmembrane protein that mediates the efflux of anticancer drugs from cells. Pgp overexpression has a distinct role in cells exhibiting multidrug resistance (MDR). We examined reversal of drug resistance in human MDR breast cancer cells by inhibition of protein kinase Cα (PKCα) activity, which is associated with Pgp-mediated efflux of anticancer drugs. PKCα activity was confirmed by measurement of phosphorylation levels of a PKCα-specific peptide substrate (FKKQGSFAKKK-NH2), showing relatively higher basal activity in drug-resistant MCF-7/ADR cells (84%) than that in drug-sensitive MCF-7 cells (63%). PKCα activity was effectively suppressed by the PKC inhibitor, Ro-31-7549, and reversal of intracellular accumulation of doxorubicin was observed by inhibition of PKCα activity in MCF-7/ADR cells compared with their intrinsic drug resistance. Importantly, increased accumulation of doxorubicin could enhance the therapeutic efficacy of doxorubicin in MDR cells significantly. These results suggest a potential for overcoming MDR via inhibition of PKCα activity with conventional anticancer drugs.

Cell proliferation effects of calix[4]arene derivatives

A series of para-tert-butylcalix[4]arene containing amide macrocyclic and acyclic derivatives at the lower rim are synthesized in this paper and their cellular effects are evaluated. G-quadruplex interaction and stabilization are assessed with compound calix-NH2 to relate it strong antiproliferative effect on cancer cell lines with G-quadruplex recognition.The calix-NH2 interact and stabilize the G-quadruplexes MYC22 and h22L and show activity in MCF-7, LNCaP, U87 cancer cell lines at low micromolar range of concentrations.

Abstract 4534: Cyclooxygenase inhibitors as delivery vehicles for histone deacetylase inhibitors

Abstract Reversible acetylation state of histones determines the existence of the chromatin in either the euchromatin state or the heterochromatin state, which in turn control the accessibility of transcription factors to promoter regions of genes on the chromatin. This reversible acetylation state is regulated by two enzymes: histone deacetylases (HDAC) and histone acetyl transferases (HAT). Imbalance in the expression of these enzymes is associated with many diseases, with equilibrium tilted towards HDAC in tumors. Reversal of the HDAC enzymes to their basal expression level, by small molecule inhibition, has been shown to significantly reduce the growth of tumors and/or completely eliminate them. Currently, there are three (3) FDA approved HDAC inhibitors in the market: vorinostat, FK228 and belinostat (all approved by the FDA for treatment of cutaneous T-cell lymphoma). Although highly effective, these compounds suffer drawbacks such as lack of activity against solid tumors, off-target toxicities, short half-life, and lack of HDAC isoform selectivity. To address some of these challenges, we chose to incorporate a targeting moiety to the head group in the classical vorinostat pharmacophoric model (comprising head group, linker and zinc binding group (ZBG)). We envisaged that selective toxicity towards tumors (hence, reduction in off-target toxicities), may be achieved if the HDAC inhibitor is selectively delivered to tumor cells expressing cyclooxygenase 2 (COX-2) enzyme. COX-2, which catalyzes the conversion of arachidonic acid to prostaglandins, is ubiquitously expressed in a wide range of cancer types and has been exploited to selectively image cancer cells in the past. To achieve this, we designed and synthesized series of hydroxamic acid-based compounds having either celecoxib or indomethacin (COX-2 inhibitors) as the targeting moiety. In addition to these compounds, we made compounds having “biaryl group” as ZBG. Compounds based on this ZBG have been reported to selectively inhibit HDAC isoforms 1&2, both culprits in a wide range of cancer types. Consistent with the reported HDAC isoform selectivity, our “biaryl” ZBG compounds potently and selectively inhibited HDACs 1& 2. Also, our hydroxamic acid-based compounds were better than vorinostat in cell-free assay and showed potent activity in MCF-7, A549 and HCT-116 cancer cell lines. Effort is underway to evaluate the in vivo activity of our lead compounds in animal models. Citation Format: Idris Olawale Raji, Emily Janeira, Fatima Yadudu, Fathi Shaghayegh, James Kornacki, Milan Mrksich, Adegboyega Oyelere. Cyclooxygenase inhibitors as delivery vehicles for histone deacetylase inhibitors. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4534. doi:10.1158/1538-7445.AM2015-4534

17β-estradiol induces stearoyl-CoA desaturase-1 expression in estrogen receptor-positive breast cancer cells.

BackgroundTo sustain cell growth, cancer cells exhibit an altered metabolism characterized by increased lipogenesis. Stearoyl-CoA desaturase-1 (SCD-1) catalyzes the production of monounsaturated fatty acids that are essential for membrane biogenesis, and is required for cell proliferation in many cancer cell types. Although estrogen is required for the proliferation of many estrogen-sensitive breast carcinoma cells, it is also a repressor of SCD-1 expression in liver and adipose. The current study addresses this apparent paradox by investigating the impact of estrogen on SCD-1 expression in estrogen receptor-α-positive breast carcinoma cell lines.MethodsMCF-7 and T47D mammary carcinomas cells and immortalized MCF-10A mammary epithelial cells were hormone-starved then treated or not with 17β-estradiol. SCD-1 activity was assessed by measuring cellular monounsaturated/saturated fatty acid (MUFA/SFA) ratios, and SCD-1 expression was measured by qPCR, immunoblot, and immunofluorescence analyses. The role of SCD-1 in cell proliferation was measured following treatment with the SCD-1 inhibitor A959372 and following SCD-1 silencing using siRNA. The involvement of IGF-1R on SCD-1 expression was measured using the IGF-1R antagonist AG1024. The expression of SREBP-1c, a transcription factor that regulates SCD-1, was measured by qPCR, and by immunoblot analyses.Results17β-estradiol significantly induced cell proliferation and SCD-1 activity in MCF-7 and T47D cells but not MCF-10A cells. Accordingly, 17β-estradiol significantly increased SCD-1 mRNA and protein expression in MCF-7 and T47D cells compared to untreated cells. Treatment of MCF-7 cells with 4-OH tamoxifen or siRNA silencing of estrogen receptor-α largely prevented 17β-estradiol-induced SCD-1 expression. 17β-estradiol increased SREBP-1c expression and induced the mature active 60 kDa form of SREBP-1. The selective SCD-1 inhibitor or siRNA silencing of SCD-1 blocked the 17β-estradiol-induced cell proliferation and increase in cellular MUFA/SFA ratios. IGF-1 also induced SCD-1 expression, but to a lesser extent than 17β-estradiol. The IGF-1R antagonist partially blocked 17β-estradiol-induced cell proliferation and SCD-1 expression, suggesting the impact of 17β-estradiol on SCD-1 expression is partially mediated though IGF-1R signaling.ConclusionsThis study illustrates for the first time that, in contrast to hepatic and adipose tissue, estrogen induces SCD-1 expression and activity in breast carcinoma cells. These results support SCD-1 as a therapeutic target in estrogen-sensitive breast cancer.

Stearoyl-CoA desaturase 1 and paracrine diffusible signals have a major role in the promotion of breast cancer cell migration induced by cancer-associated fibroblasts.

Background:Despite the recognised contribution of the stroma to breast cancer development and progression, the effective targeting of the tumor microenvironment remains a challenge to be addressed. We previously reported that normal fibroblasts (NFs) and, notably, breast cancer-associated fibroblasts (CAFs) induced epithelial-to-mesenchymal transition and increases in cell membrane fluidity and migration in well- (MCF-7) and poorly-differentiated (MDA-MB-231) breast cancer cells. This study was designed to better define the role played, especially by CAFs, in promoting breast tumor cell migration.Methods:Fibroblast/breast cancer cell co-cultures were set up to investigate the influence of NFs and CAFs on gene and protein expression of Stearoyl-CoA desaturase 1 (SCD1), the main enzyme regulating membrane fluidity, as well as on the protein level and activity of its transcription factor, the sterol regulatory element-binding protein 1 (SREBP1), in MCF-7 and MDA-MB-231 cells. To assess the role of SREBP1 in the regulation of SCD1 expression, the desaturase levels were also determined in tumor cells treated with an SREBP1 inhibitor. Migration was evaluated by wound-healing assay in SCD1-inhibited (by small-interfering RNA (siRNA) or pharmacologically) cancer cells and the effect of CAF-conditioned medium was also assessed. To define the role of stroma-derived signals in cancer cell migration speed, cell-tracking analysis was performed in the presence of neutralising antibodies to hepatocyte growth factor, transforming growth factor-β or basic fibroblast growth factor.Results:A two to three fold increase in SCD1 mRNA and protein expression has been induced, particularly by CAFs, in the two cancer cell lines that appear to be dependent on SREBP1 activity in MCF-7 but not in MDA-MB-231 cells. Both siRNA-mediated and pharmacological inhibition of SCD1 impaired tumor cells migration, also when promoted by CAF-released soluble factors. Fibroblast-triggered increase in cancer cell migration speed was markedly reduced or abolished by neutralising the above growth factors.Conclusion:These results provide further insights in understanding the role of CAFs in promoting tumor cell migration, which may help to design new stroma-based therapeutic strategies.

Search for human DNA topoisomerase II poisons in the group of 2,5-disubstituted-1,3,4-thiadiazoles

A series of six 2,5-disubstituted 1,3,4-thiadiazole derivatives was synthesized and examined for cytotoxic activity in MCF-7 and MDA-MB-231 breast cancer cells. MTT assay confirmed that 2-(3-fluorophenylamino)-5-(3-hydroxyphenyl)-1,3,4-thiadiazole (2), 2-(4-bromophenylamino)-5-(2,4-dichlorophenyl)-1,3,4-thiadiazole (3), 2-(4-fluorophenylamino)-5-(2,4-dichlorophenyl)-1,3,4-thiadiazole (4), had ability to inhibit MCF-7 and MDA-MB-231 cells proliferation. The IC50 values for the mentioned compounds ranged between 120 and 160 μM (with respect to MCF-7 cells) and from 70 to 170 μM (with respect to MDA-MB-231 cells). It turned out, moreover, that compound 2 is a human topoisomerase II (topoII) catalytic inhibitor whereas the two other compounds (i.e. 3 and 4) are capable of stabilizing DNA-topoII cleavage complex and thus are topoII poisons.

Synthesis and biological evaluation of geldanamycin analogs against human cancer cells.

To find novel potential and less toxic benquinone anamycin heat shock protein 90 (Hsp90) inhibitors as anticancer agents, a limited series of 17-substituted or 17,19-disubstituted 17-demethoxygeldanamycin analogs were synthesized and tested for anti-proliferation activity against human cancer cells. Liver toxicity was also tested in vivo. Five 17-alkylamino-17-demethoxygeldanamycins and two 17-alkylamino-19-methylthio-17-demethoxygeldanamycins were synthesized from geldanamycin (GA) and 19-methylthiogeldanamycin (19-S(methyl)-GA), respectively. Anti-proliferation activities of the GA analogs were determined in MCF7, HeLa, HCT116 and HepG2 cells using the MTT method. Western blot and cell cycle analyses were performed for mechanistic study. The growth inhibition effect of potential geldanamycins was also investigated in normal Buffalo rat liver (BRL) cells. In vivo liver toxicity was tested in Institute of Cancer Research (ICR) mice by tail vein injection of the tested compounds. Most of the 17-alkylaminogeldanamycins exhibited obvious growth inhibition effects on multiple human cancer cell lines. The anti-proliferation activity of 19-methylthio-substituted geldanamycins was significantly lower compared with no 19-substitution geldanamycins in all tested cancer cells. The compound 1b (17-[2-(piperidinyl-1'-yl)-ethylamino]-17-demethoxygeldanamycin) exhibited the highest anti-proliferation activity in MCF7, HeLa and HCT116 cells, which was much more effective than GA and the developing Hsp90 inhibitor 17-AAG (17-allylamino-17-demethoxygeldanamycin). Meanwhile, compound 1b exhibited weaker growth inhibition effect on BRL cell line than GA and 17-AAG. 1b induced cell cycle arrest at the G2/M phase in MCF7 cells. Cleavage of PARP associated with apoptosis and degradation of the Hsp90 client protein Akt and Her2 was also induced by treatment of 1b in HeLa and MCF7 cell lines. In spite of the relatively weaker activity of 1b compared with GA and 17-AAG against HepG2 cells, 1b was further identified with lower hepatotoxicity than GA in vivo. Compound 1b is regarded as a new potential Hsp90 inhibitor with low hepatotoxicity for further study.

Arsenic trioxide downregulates cancer procoagulant activity in MCF-7 and WM-115 cell lines in vitro.

The aim of the studyTo analyze human breast cancer cell line MCF-7 and human malignant melanoma cell line WM-115 in order to characterize the cellular expression of CP and to evaluate whether ATO may affect this activity, as well as the viability of the cells.Material and methodsThe inhibitory effect of arsenic trioxide on the proliferation of MCF-7 and WM-115 cells were measured with MTT test. The activity of cancer procoagulant after ATO exposure was determined by a specific three-stage chromogenic assay.ResultsATO decreased the CP activity in a dose- and time-dependent manner in MCF-7 cells with no effect on cell proliferation at the same time. However, it affected the CP activity of WM-115 cells in a different way. Reduction in CP activity was followed by an increase after 48 h incubation. The cells viability results showed dose-and time-correlated response within high arsenic concentrations.ConclusionsArsenic trioxide downregulates the CP expression in human breast cancer and melanoma cells.

Ceramide synthases CerS4 and CerS5 are upregulated by 17β-estradiol and GPER1 via AP-1 in human breast cancer cells

Ceramide synthases (CerS) are important enzymes of the sphingolipid pathway, responsible for the production of ceramides with distinct chain lengths. In human breast cancer tissue, we detected a significant increase in CerS4 and CerS6 mRNA in estrogen receptor positive (ER+) cancer tissue. To clarify the molecular mechanism of this upregulation, we cloned CerS2, -4, -5 and CerS6 promoter and 3′-UTR fragments into luciferase reporter gene plasmids and determined luciferase activity in MCF-7 (ERα/β) and MDA-MB-231 (ERβ) cells after 17β-estradiol treatment. Only the activities of CerS4 and CerS5 promoter Luc constructs, as well as CerS2- and CerS5-3′-UTR Luc constructs increased after estradiol treatment in MCF-7 cells, and this could be inhibited by the anti-estrogen fulvestrant. Co-transfection with the G protein-coupled estrogen receptor 1 (GPER1) also enhanced CerS2, CerS4 and CerS6 promoter activity whereas CerS5 promoter activity was inhibited in both cell lines. Promoter deletion and mutation constructs from CerS4 and CerS5 promoters revealed that estradiol and GPER1 mediate their effects on both promoters by activating AP-1, most likely through dimerization of c-Jun and c-Fos. At least we could show, that cell proliferation induced by estradiol could be blocked by co-treatment with Fumonisin B1, indicating that upregulation of CerS in breast cancer cells by estrogen is important for cell proliferation and possibly tumor development. In conclusion, our data highlight transcriptional and posttranscriptional mechanisms regulating CerS expression in human cells which provide the basis for further studies investigating the regulation of CerS expression and ceramide synthesis after diverse stimuli in physiological and pathophysiological processess.

Indirubin derivatives alter DNA binding activity of the transcription factor NF-Y and inhibit MDR1 gene promoter

Indirubin derivatives exert antitumor activity. However, their effects on the expression of multidrug resistance gene 1 (MDR1) have not been investigated. Here we found three derivatives that inhibit the MDR1 gene promoter. To investigate the effects of indirubins on the DNA binding of NF-Y, a major MDR1 gene transcription factor that recognizes an inverted CCAAT element in the promoter, gel mobility shift assay was performed using the element as a probe with nuclear extracts from NG108-15, MCF7, HepG2, C2C12, and SK-N-SH cells. Among 17 compounds, 5-methoxyindirubin inhibited the DNA binding of NF-Y significantly, whereas indirubin-3′-oxime and 7-methoxyindirubin 3′-oxime increased the binding considerably. After evaluating a suitable concentration of each compound for transcription analysis using living tumor cells, we performed a reporter gene assay using a reporter DNA plasmid containing EGFP cDNA fused to the MDR1 gene promoter region. Indirubin-3′-oxime exerted a significant inhibitory effect on the MDR1 promoter activity in MCF7 and HepG2 cells, and 5-methoxyindirubin inhibited the activity only in MCF7 cells; 7-methoxyindirubin 3′-oxime suppressed the activity in all of the cell lines. We further confirmed that the compounds reduced endogenous MDR1 transcription without any inhibitory effect on NF-Y expression. Moreover, each compound increased the doxorubicin sensitivity of MCF7 cells. These results indicate that each indirubin derivative acts on the DNA binding of NF-Y and represses the MDR1 gene promoter with tumor cell-type specificity.

A771726, an anti-inflammatory drug, exerts an anticancer effect and reverses tamoxifen resistance in endocrine-resistant breast cancer cells.

A771726, an orally available anti-inflammatory agent, has been approved for the treatment of multiple sclerosis by diminishing entire inflammatory responses through multiple signaling pathways. Recently, a few emerging studies have focused on the potential application of A771726 in cancer therapy, less on the treatment of breast cancer and particularly on overcoming drug resistance in breast cancer. We report here for the first time the cytotoxic activity and drug resistance reversal of A771726 in acquired tamoxifen-resistant breast cancer cell line MCF-7/LCC9. We discovered that A771726 treatment showed antiproliferative activities in MCF-7/LCC9 cells, which were even more sensitive to A771726 than their parental tamoxifen-sensitive cells (MCF‑7). A771726 also exerted pro-apoptotic activities and induced cell cycle arrest at the G1 phase. Notably, treatment of A771726 restored the sensitivity of MCF-7/LCC9 cells to tamoxifen. Western blot analysis revealed that A771726 decreased the phosphorylation level of Src, one key driver of tamoxifen resistance. Moreover, in order to comprehensively clarify the mechanisms of A771726 in anti-estrogen-resistant cells, we explored a genome-wide transcriptomic analysis, and showed that A771726 could modulate multiple signaling pathways (e.g. cell cycle, apoptosis, MAPK, metabolism and p53 signaling pathway) and cellular processes (e.g. signal transduction, transcription and cell cycle). Overall, our results indicate that A771726 alone and the combination of A771726 with anti-estrogens may be of therapeutic benefit for ER-positive and endocrine-resistant breast cancer.

Pterostilbene as a Potential Novel Telomerase Inhibitor: Molecular Docking Studies and Its in vitro Evaluation

Pterostilbene is a naturally occurring dimethyl ether analog of resveratrol identified in several plant species. Telomerase is important in tumor initiation and cellular immortalization. Given the striking correlations between telomerase activity and proliferation capacity in tumor cells, telomerase had been considered as a potentially important molecular target in cancer therapeutics. Molecular docking studies were performed on pterostilbene with the crystal structure of telomerase (3DU6). Pterostilbene was evaluated for its in vitro cytotoxicity in breast (MCF7) and lung cancer (NCI H-460) cell lines, antimitotic activity in green grams and telomerase activity. Curcumin was used as a standard. Docking results indicated good interaction between pterostilbene and the active site of telomerase and the docked energy of pterostilbene was -7.10 kcal/mol. Pterostilbene showed strong inhibitory effect on in vitro telomerase activity and cell growth in both the cell lines tested in a dose dependent manner. Cancer cells treated with 80 µM pterostilbene exhibited significant telomerase inhibition, after 72 hours (MCF-7 and NCI H-460; 81.52% and 74.69% reduction, respectively, compared to control). The IC50 of pterostilbene for anti-proliferative activity in MCF7 and NCI H-460 cell lines were found to be 30.0 and 47.2 µM, respectively. The best antimitotic activity was obtained with 80 μM of pterostilbene (100% reduction in water imbibition). All the above results were comparable to that of curcumin. The drug-related properties of pterostilbene were calculated using Molinspiration, Osiris Property Explorer and ACD/Chemsketch softwares. Pterostilbene obeyed Lipinski's Rule of Five indicating its therapeutic potential in humans. It was found that the telomerase inhibitory activity exhibited by pterostilbene was dependent of the cell viability and has the potential to be a new drug candidate against breast and lung cancers.

Comparision influence of conditioned medium of human mesenchimal cells and interferon-α on development of tumor cell population

This work is a study of mediators and mechanisms of the effect of human mesenchymal stem cells from bone marrow (hMSC BM) on the tumor cell population line MCF-7 (breast adenocarcinoma). It is known that MSCs produce a wide range of cytokines and chemokines, and provide humoral cells interaction. BM MSCs produce tumor necrosis factor (TNF-α), interleukin (IL-1β, IL-2, IL-4, IL-6, IL-8), interferon-alpha (IFN-α). In this study we compared the proliferation, adhesion, survival and antigenic profile of breast adenocarcinoma cells that were cultured with conditioned medium (с-medium) of the MSC and IFN-α. Consequently, it was found that с-medium from MSC inhibited proliferation activity of MCF-7, increased cells adhesion, suppressed the ability to migrate, and reduced the expression of estrogen receptor and epidermal growth factor receptor. Conversely expression of cytokeratins increased, which is a positive sign for the tumor cells of epithelial origin. IFN-α showed a more pronounced effect on the tumor population. These findings suggest that cryopreserved MSC BM has antitumor activity. Also, our data suggest that IFN-alpha is one of the mediators of antitumor effect of MSCs.

In-Vitro and in-Silico characterization of Sophora interrupta plant extract as an anticancer activity.

Sophora interrupta belongs to the family of Fabaceae and the species in this genus have a diverse medicinal importance as a folk medicine for preventing many ailments including cancer. In order to evaluate the anticancer activity of S.interrupta, we have performed in vitro anti-oxidant, anti-inflammatory, anti-proliferative, and cell based anticancer activity in MCF-7 and PC-3 cell lines. Secondary metabolites of S.interrupta were used to identify anticancer compounds using Open Eye software. The antioxidant activity of the S.interrupta root ethylacetate (SEA) extract at 100 µg/ml is equal to that of ascorbic acid at 50 µg/ml. The antiinflammatory activity of SEA is half of that of diclofenac at 50 µg/ml. Anticancer activity was detected by measuring the mitochondrial dehydrogenase activity (MTT assay). The half maximal inhibitory concentrations (IC50) for MCF-7 and PC-3 cell lines are 250 and 700 µg/ml respectively. This was supported by the morphological changes such as membrane blebbing, cell detachment and rounded cell morphology when compared to the parental cells. In addition, we observed few green cells (live) over red cells (dead) based on the uptake of acridine orange and ethidium bromide dyes. Kaempferol-3-O-b-D-glucopyranoside, a Secondary metabolite of S.interrupta form 6 hydrogen bond interactions with Arg 202, Gln 207, Gly 227, Gly 229, Thr 231 and Ala 232 human DEAD box RNA helicase, DDX3 protein and is equivalent to crystal structure of adenosine mono phosphate to DDX3. Overall, it suggests that the SEA extract has anticancer compounds, and it can be used to enhance death receptor mediated cancer cell death.

Neutral and Ionic Cycloruthenated 2-Phenylindoles as Cytotoxic Agents

The synthesis and characterization of two families of cyclometalated Ru(II) complexes with the new (Csp2,Nindole)− motif formed by activation of the C–H bonds of 2-phenylindole ligands of the general formula {(4′-R1-C6H4)-3-NOMe-5-R2-6-R3-(C6H2N)} are presented. The novel ruthenacycles show a remarkable cytotoxic activity in MCF7 and MDA-MB231 breast cancer cell lines, which clearly exceeds those of the trans and cis isomers of [PtCl2(L)(DMSO)] derived from the same ligands and even that of cisplatin.

Clofarabine, a novel adenosine analogue, reactivates DNA methylation-silenced tumour suppressor genes and inhibits cell growth in breast cancer cells

Clofarabine (2-chloro-2′-fluoro-2′-deoxyarabinosyladenine, ClF) is a second-generation 2′-deoxyadenosine analogue that is structurally related to cladribine (2-chloro-2′-deoxyadenosine, 2CdA) and fludarabine (9-beta-d-arabinosyl-2-fluoroadenine, F-ara-A). It demonstrates potent antitumour activity at much lower doses than parent compounds with high therapeutic efficacy in paediatric blood cancers. Our previous studies in breast cancer cells indicate that 2CdA and F-ara-A are involved in epigenetic regulation of gene transcription. We therefore investigated whether ClF influences methylation and expression of selected tumour suppressor genes, such as adenomatous polyposis coli (APC), phosphatase and tensin homologue (PTEN), and retinoic acid receptor beta 2 (RARbeta2), as well as expression of p53, p21 and DNA methyltransferase 1 (DNMT1) in MCF-7 and MDA-MB-231 breast cancer cell lines with different invasive potential. Promoter methylation and gene expression were estimated using methylation-sensitive restriction analysis (MSRA) and real-time PCR, respectively. ClF demonstrated potent growth inhibitory activity in MCF-7 and MDA-MB-231 cells after 96h treatment with IC50 determined as equal to 640nM and 50nM, respectively. In both breast cancer cell lines, ClF led to hypomethylation and up-regulation of APC, PTEN and RARbeta2 as well as increase in p21 expression. Only in non-invasive MCF-7 cells, these changes were associated with down-regulation of DNMT1. Our results provide first evidence of ClF implications in epigenetic regulation of transcriptional activity of selected tumour suppressor genes in breast cancer. It seems to be a new important element of ClF anticancer activity and may indicate its potential efficacy in epigenetic therapy of solid tumours, especially at early stages of carcinogenesis.