MCF-7 Human Mammary Carcinoma Research Articles

Validity of the cell-extracted proteome as a substrate pool for exploring phosphorylation motifs of kinases.

Three representative protein kinases with different substrate preferences, ERK1 (Pro-directed), CK2 (acidophilic), and PKA (basophilic), were used to investigate phosphorylation sequence motifs in substrate pools consisting of the proteomes from three different cell lines, MCF7 (human mammary carcinoma), HeLa (human cervical carcinoma), and Jurkat (human acute T-cell leukemia). Specifically, recombinant kinases were added to the cell-extracted proteomes to phosphorylate the substrates in vitro. After trypsin digestion, the phosphopeptides were enriched and subjected to nanoLC/MS/MS analysis to identify their phosphorylation sites on a large scale. By analyzing the obtained phosphorylation sites and their surrounding sequences, phosphorylation motifs were extracted for each kinase-substrate proteome pair. We found that each kinase exhibited the same set of phosphorylation motifs, independently of the substrate pool proteome. Furthermore, the identified motifs were also consistent with those found using a completely randomized peptide library. These results indicate that cell-extracted proteomes can provide kinase phosphorylation motifs with sufficient accuracy, even though their sequences are not completely random, supporting the robustness of phosphorylation motif identification based on phosphoproteome analysis of cell extracts as a substrate pool for a kinase of interest.

Synthesis and Cytotoxicity Evaluation of Tyrosine-5 Fluorinated Analogues of RA-VII, An Antitumor Bicyclic Hexapeptide

AbstractRA-VII analogues fluorinated at each ε-position of Tyr-5 were designed. The synthesis of these peptide analogues commenced with the preparation of atropisomeric fluorocycloisodityrosines from protected 3-fluoro-L-tyrosyl-3-boronyl-L-tyrosine mediated by copper(II) acetate and 4-(dimethylamino)pyridine. After N-methylation, the tetrapeptide segment was coupled with the N-terminus of each fluorocycloisodityrosine to afford a hexapeptide. After removal of the C- and N-terminal protecting groups, each peptide was subjected to macrocyclization to produce an analogue. The analogue with a β-oriented fluorine atom was equipotent to RA-VII with regard to cytotoxicity toward human mammary carcinoma MCF-7 cells, and showed 2.1-fold and 1.4-fold lower cytotoxicities than RA-VII toward human promyelocytic leukemia HL-60 and human colorectal cancer HCT-116 cells, respectively, whereas the analogue with an α-oriented fluorine atom showed 7.7-fold, 6.0-fold, and 14-fold lower cytotoxicities than RA-VII toward those cells, respectively.

O-GlcNAcylation Enhances Double-Strand Break Repair, Promotes Cancer Cell Proliferation, and Prevents Therapy-Induced Senescence in Irradiated Tumors

The metabolic reprogramming associated with characteristic increases in glucose and glutamine metabolism in advanced cancer is often ascribed to answering a higher demand for metabolic intermediates required for rapid tumor cell growth. Instead, recent discoveries have pointed to an alternative role for glucose and glutamine metabolites as cofactors for chromatin modifiers and other protein posttranslational modification enzymes in cancer cells. Beyond epigenetic mechanisms regulating gene expression, many chromatin modifiers also modulate DNA repair, raising the question whether cancer metabolic reprogramming may mediate resistance to genotoxic therapy and genomic instability. Our prior work had implicated N-acetyl-glucosamine (GlcNAc) formation by the hexosamine biosynthetic pathway (HBP) and resulting protein O-GlcNAcylation as a common means by which increased glucose and glutamine metabolism can drive double-strand break (DSB) repair and resistance to therapy-induced senescence in cancer cells. We have examined the effects of modulating O-GlcNAcylation on the DNA damage response (DDR) in MCF7 human mammary carcinoma in vitro and in xenograft tumors. Proteomic profiling revealed deregulated DDR pathways in cells with altered O-GlcNAcylation. Promoting protein O-GlcNAc modification by targeting O-GlcNAcase or simply treating animals with GlcNAc protected tumor xenografts against radiation. In turn, suppressing protein O-GlcNAcylation by blocking O-GlcNAc transferase activity led to delayed DSB repair, reduced cell proliferation, and increased cell senescence in vivo. Taken together, these findings confirm critical connections between cancer metabolic reprogramming, DDR, and senescence and provide a rationale to evaluate agents targeting O-GlcNAcylation in patients as a means to restore tumor sensitivity to radiotherapy. IMPLICATIONS: The finding that the HBP, via its impact on protein O-GlcNAcylation, is a key determinant of the DDR in cancer provides a mechanistic link between metabolic reprogramming, genomic instability, and therapeutic response and suggests novel therapeutic approaches for tumor radiosensitization.

BIOACTIVITIES AND CHEMOPROFILING COMPARISONS OF CHENOPODIUM AMBROSIOIDES L. AND CHENOPODIUM BOTRYS L. GROWING IN KASHMIR, INDIA

Objectives: The objectives of the study were the gas chromatography-mass spectrometry (GC-MS) identification and comparison of the chemical constituents, evaluation of the antifungal and anticancer activities of two species of genus Chenopodium, for example, Chenopodium ambrosioides (Ca) and Chenopodium botrys (Cb) growing in Kashmir, Himalayan region.Methods: The hydrodistilled essential oil of Ca and Cb was subjected to GC-MS analysis and antifungal activity for minimum inhibitory concentration (MIC) determination against different human pathogenic fungal strains using broth microdilution assay in 96-well microtiter plates as per the protocol of the clinical and laboratory standards institute (2008 M27-A3). The anti-proliferative ability of the essential oils was also evaluated against the two cell lines MCF-7 (human mammary carcinoma cells) and A549 (Human lung adenocarcinoma epithelial cells).Results: A total of 34 compounds identified in Ca with α-terpinene (37.17%), isoascaridole (20.48%), and ascaridole (14.83%) as the key compounds. The key compounds of Cb were shyobunol (18.91%), and hedycaryol (9.51%), germacrene-D-4-ol (8.57%), with 65 identified compounds. Both the species were found to have comparable antifungal activities against human pathogenic fungi with MIC80 values in the range of 0.031 mg/ml– 0.256 mg/ml for Ca and 0.031 mg/ml–0.126 mg/ml in case of Cb. Maximum anti-proliferative activity was observed at 125 μg/ml concentration in A549 cell line, while as the oils inhibited the growth of MCF-7 cell line at a lower concentration of 31.25 μg/ml.Conclusion: The essential oils of Ca and Cb were found to have potent anticancer and antifungal activities and can have potential use as a natural fungicide.

BIOACTIVITIES AND CHEMOPROFILING COMPARISONS OF CHENOPODIUM AMBROSIOIDES L. AND CHENOPODIUM BOTRYS L. GROWING IN KASHMIR, INDIA

Objectives: The objectives of the study were the gas chromatography-mass spectrometry (GC-MS) identification and comparison of the chemical constituents, evaluation of the antifungal and anticancer activities of two species of genus Chenopodium, for example, Chenopodium ambrosioides (Ca) and Chenopodium botrys (Cb) growing in Kashmir, Himalayan region.Methods: The hydrodistilled essential oil of Ca and Cb was subjected to GC-MS analysis and antifungal activity for minimum inhibitory concentration (MIC) determination against different human pathogenic fungal strains using broth microdilution assay in 96-well microtiter plates as per the protocol of the clinical and laboratory standards institute (2008 M27-A3). The anti-proliferative ability of the essential oils was also evaluated against the two cell lines MCF-7 (human mammary carcinoma cells) and A549 (Human lung adenocarcinoma epithelial cells).Results: A total of 34 compounds identified in Ca with α-terpinene (37.17%), isoascaridole (20.48%), and ascaridole (14.83%) as the key compounds. The key compounds of Cb were shyobunol (18.91%), and hedycaryol (9.51%), germacrene-D-4-ol (8.57%), with 65 identified compounds. Both the species were found to have comparable antifungal activities against human pathogenic fungi with MIC80 values in the range of 0.031 mg/ml– 0.256 mg/ml for Ca and 0.031 mg/ml–0.126 mg/ml in case of Cb. Maximum anti-proliferative activity was observed at 125 μg/ml concentration in A549 cell line, while as the oils inhibited the growth of MCF-7 cell line at a lower concentration of 31.25 μg/ml.Conclusion: The essential oils of Ca and Cb were found to have potent anticancer and antifungal activities and can have potential use as a natural fungicide.

Development of novel inorganic strontium nanoparticles for delivery of pDNA and siRNA to breast cancer cell

Event Abstract Back to Event Development of novel inorganic strontium nanoparticles for delivery of pDNA and siRNA to breast cancer cell ATHIRAH BAKHTIAR1*, Md Ezharul H. Chowdhury2, Iekhsan Othman3 and Anuar Zaini3 1 Faculty of Pharmacy, Mahsa University, Malaysia 2 Monash University Malaysia, Malaysia 3 Monash University, Australia Background Recent studies have been focused on developing smart nanoparticles for efficient delivery of transgenes and siRNAs into cancerous cells of an animal model through active and passive targeting. Precipitation reaction is one of the facile and convenient ways to generate inorganic strontium nanoparticles, in which an insoluble salt is formed after mixing two water-soluble salts. Advantages in comparison with other methods include requiring only simple equipment, ability to prepare and control particle size and composition in near ambient temperature and pressure. The approach would pave a new way for facile, low toxicity and large-scale synthesis of inorganic nanoparticles with well-controlled dimensions and properties. Methods The study involved the formation of 5 different types of inorganic strontium nanocrystals via precipitation reactions, with various observational studies involving pH, temperature, salt concentration and time of incubation. Strontium particle sizes were determined using zetasizer and scanning electron microscope prior to binding studies. The nanoparticles were then subjected to various cellular studies including cellular uptake and cytotoxicity studies through incorporation of p53 and MAPK siRNA, forming gene-nanoparticle complexes onto human and mice mammary carcinoma cells, MCF-7 and 4T1 cells, respectively. Unloaded strontium nanoparticles formed were also observed for toxicity effect against both cells. Results Studies showed that strontium fluoride and strontium carbonate were smaller in size in comparison to other strontium salt particles, averaging in 100-300nm in diameter. Additionally, cellular studies revealed that gene-loaded strontium sulfite and strontium fluoride were responsible for greater cytotoxicity effect, in comparison naked gene treatment. Low toxicity effect was seen with unloaded strontium nanoparticles. Studies were compared against established inorganic carbonate apatite nanoparticles. Conclusion Nano-sized strontium particles showed great potential to be applied for in vivo studies, ideally seen with strontium sulfite and strontium fluoride, via the gene delivery system in the cellular level. Keywords: breast cancer, pDNA delivery, siRNA, Strontium, Nanoparticles Conference: International Conference on Drug Discovery and Translational Medicine 2018 (ICDDTM '18) “Seizing Opportunities and Addressing Challenges of Precision Medicine”, Putrajaya, Malaysia, 3 Dec - 5 Feb, 2019. Presentation Type: Poster Presentation Topic: Cancer Citation: BAKHTIAR A, Chowdhury MH, Othman I and Zaini A (2019). Development of novel inorganic strontium nanoparticles for delivery of pDNA and siRNA to breast cancer cell. Front. Pharmacol. Conference Abstract: International Conference on Drug Discovery and Translational Medicine 2018 (ICDDTM '18) “Seizing Opportunities and Addressing Challenges of Precision Medicine”. doi: 10.3389/conf.fphar.2018.63.00137 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 04 Oct 2018; Published Online: 17 Jan 2019. * Correspondence: Dr. ATHIRAH BAKHTIAR, Faculty of Pharmacy, Mahsa University, Bandar Saujana Putra, Selangor, 42610, Malaysia, athirahbakhtiar@gmail.com Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers ATHIRAH BAKHTIAR Md Ezharul H Chowdhury Iekhsan Othman Anuar Zaini Google ATHIRAH BAKHTIAR Md Ezharul H Chowdhury Iekhsan Othman Anuar Zaini Google Scholar ATHIRAH BAKHTIAR Md Ezharul H Chowdhury Iekhsan Othman Anuar Zaini PubMed ATHIRAH BAKHTIAR Md Ezharul H Chowdhury Iekhsan Othman Anuar Zaini Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Micelles with Sheddable Dendritic Polyglycerol Sulfate Shells Show Extraordinary Tumor Targetability and Chemotherapy in Vivo.

Cancer nanomedicines are typically stealthed by a poly(ethylene glycol) layer that is important to obtain extended blood circulation and elevated tumor accumulation. PEG stealth, however, also leads to poor tumor cell selectivity and uptake thereby reducing treatment efficacy. Here, we report that biodegradable micelles with sheddable dendritic polyglycerol sulfate (dPGS) shells show an unusual tumor targetability and chemotherapy in vivo. The self-assembly of dPGS-SS-poly(ε-caprolactone) amphiphilic block copolymer with an Mn of 4.8-3.7 kg mol-1 affords negatively charged and small sized micelles (dPGS-SS-PCL Ms). dPGS-SS-PCL Ms reveal a low cytotoxicity, decent doxorubicin (DOX) loading, and accelerated drug release under a reductive condition. Notably, DOX-loaded dPGS-SS-PCL Ms exhibit a high tolerable dosage of more than 40 mg kg-1, a long plasma half-life of ca. 2.8 h, and an extraordinary tumor accumulation. Intriguingly, therapeutic results demonstrate that DOX-loaded dPGS-SS-PCL Ms induce complete tumor suppression, significantly improved survival rate, and diminishing adverse effects as compared to free drug (DOX·HCl) in MCF-7 human mammary carcinoma models. Dendritic polyglycerol sulfate with a superior tumor homing ability appears to be an attractive alternative to PEG in formulating targeted cancer nanomedicines.

The combined effects of all-trans-retinoic acid and docosahexaenoic acid on the induction of apoptosis in human breast cancer MCF-7 cells.

Breast cancer is one of the most women's cancers in the worldwide. In vivo and in vitro studies showed that all-trans-retinoic acid (ATRA) and docosahexaenoic acid (DHA) can modulate differentiation and apoptosis in both cancer and immune cells. Nuclear retinoic acid receptors (RARs) and retinoid X receptors (RXRs) activation in the presence of their ligands, plays a critical role in the proliferation, differentiation, and apoptosis of normal cells. We hypothesized that ATRA and DHA, as ligands of RARs and RXRs respectively, may have synergistic effects on the induction of apoptosis in MCF-7 human mammary carcinoma cell lines. MCF-7 cells were seeded in a 24-well plate at 3 × 105 cells per well. The cells were treated with 5 µM ATRA, 30 DHA, and various combinations of them over a 3-day trial. Apoptosis was measured by Annexin V-FITC kit and flow cytometery. Our results showed that the combination treatment of ATRA and DHA (5 µM and 30 µM and half dose at 2.5 µM and 15 µM, respectively) in a dose-dependent manner induced apoptosis rate in MCF-7 cells significantly more than single treatment of ATRA or DHA, as compared to control group (P < 0.05). We conclude that the combination of ATRA and DHA at the well-balanced proportion may be effective in cancer cell apoptosis. Further studies provide details about the potential synergistically effects of combination treatment of ATRA and DHA in growth inhibition and differentiation of human mammary cancer cells.

Frequent infection of human cancer xenografts with murine endogenous retroviruses in vivo.

Infection of human cancer xenografts in mice with murine leukemia viruses (MLVs) is a long-standing observation, but the likelihood of infection in vivo and its biological consequences are poorly understood. We therefore conducted a prospective study in commonly used xenograft recipient strains. From BALB/c nude mice engrafted with MCF7 human mammary carcinoma cells, we isolated a virus that was virtually identical to Bxv1, a locus encoding replication-competent xenotropic MLV (XMLV). XMLV was detected in 9/17 (53%) independently isolated explants. XMLV was not found in primary leukemias or in THP1 leukemia cells grown in Bxv1-negative NSG (NOD/SCID/γCnull) mice, although MCF7 explants harbored replication-defective MLV proviruses. To assess the significance of infection for xenograft behavior in vivo, we examined changes in growth and global transcription in MCF7 and the highly susceptible Raji Burkitt lymphoma cell line chronically infected with XMLV. Raji cells showed a stronger transcriptional response that included up-regulation of chemokines and effectors of innate antiviral immunity. In conclusion, the risk of de novo XMLV infection of xenografts is high in Bxv1 positive mice, while infection can have positive or negative effects on xenograft growth potential with significant consequences for interpretation of many xenograft studies.

Using a sequence of estrogen response elements as a DNA aptamer for estrogen receptors in vitro.

Estrogen receptors (ERs) are overexpressed in approximately 70% of breast cancer cases, and they play an important role in tumorigenesis. ERs are strong predictive factors for measuring responses to hormonal therapies. Aptamers are short and single stranded oligonucleotides that are able to recognize target molecules with high affinity. In the present study, we selected and synthesized an oligonucleotide, which has a similar sequence to estrogen response element in the Xenopus Vitellogenin A2 gene. The synthesized oligonucleotide was evaluated by using immunostaining of paraffin-embedded breast cancer tissues and treating MCF-7 human mammary carcinoma cell line in vitro. We found that the synthesized oligonucleotide had a high binding affinity to ER similar to estradiol. Using a specific anti-ER antibody as a standard control, we showed that the synthesized oligonucleotide specifically recognized and immunostained tumor cells of breast cancer without cross-reaction with normal tissues. The overall agreement of ER detection between the anti-ER antibody and the ER aptamer was 97.1% (kappa value=0.943; 95% CI=0.879-1.006; p<0.002). Similar to tamoxifen or fulvestrant, the oligonucleotide also had an inhibitory effect on cell proliferation of MCF-7 cell line in a dose- and time-dependent fashion but had no cytotoxic effect on human normal mammary epithelial cells. Therefore, the synthesized oligonucleotide may be used as an aptamer for immunostaining of paraffin-embedded tissue sections for breast cancer diagnosis, as well as a potential ER antagonist in the treatment of breast cancer.

Identification of lipidomic biomarkers for coexposure to subtoxic doses of benzo[a]pyrene and cadmium: the toxicological cascade biomarker approach.

The search for model bioassay systems indicating activation of different toxicological signaling pathways is one of the paramount goals of modern toxicology. Especially coexposure scenarios need to be investigated with respect to synergistic and interdependent effects for the activation of toxicological signaling pathways. The present study introduces an experimental in vitro model system for nontoxic and low-dose coexposures of human mammary carcinoma MCF-7 cells against polycyclic aromatic hydrocarbons (PAHs) such as benzo[a]pyrene (BP) and heavy metals such as cadmium. For the first time, a multivariate model that identifies 18 metabolic biomarkers has been shown to be sufficient to separate BP-treated cells from coexposed or control cells. A "toxicological pathway color code model" is introduced to visualize the results. Different biomarker subsets can be associated with specific HER2 signaling steps. A tiered cascade biomarker approach is proposed that could be used to identify profiles associated with tumorigenic potency of environmental toxicants in coexposure scenarios, including possible synergistic or additive effects.

Comparative Efficacy of Extracts from Lycium Barbarum Bark and Fruit on Estrogen Receptor Positive Human Mammary Carcinoma MCF-7 Cells

Chemo-endocrine therapy for estrogen receptor positive (ER+) breast cancer exhibits acquired tumor resistance. Herbal medicines provide integrative support for breast cancer patients. Present study compared the efficacy of aqueous extracts from Lycium barbarum bark (LBB) and Lycium barbarum fruit (LBF) on ER+ MCF-7 cells. Cellular growth and 17ß-estradiol (E2) metabolism quantified the efficacy. MCF-7 cells maintained in serum depleted medium+ E2 exhibited increased anchorage-dependent and anchorage-independent growth. LBB exhibited greater potency than LBF (95% reduction in IC50). LBB produced a 6.8-fold increase, 40% decrease, and a 3.7-fold increase in 2-hydroxyestrone (2-OHE1), 16α-hydroxyestrone (16α-OHE1), and estriol (E3) formation. The corresponding values for LBF were 3.9, 33, and 10.5. LBB produced a16.3-fold and a twofold increase in 2-OHE1:16α-OHE1 and E3:16α-OHE1 ratios, whereas LBF produced a sixfold and a 2.9-fold increase. The efficacy of LBB is due to increased 2-OHE1 formation, whereas that of LBF is due to accelerated conversion of 16α-OHE1 to E3. Specific growth inhibitory profiles of LBB and LBF may be due to their distinct chemical composition and their complementary actions on E2 metabolism. This study validates a mechanistic approach to identify efficacious herbal extracts for clinical ER+ breast cancer.

Effects of triclocarban on the transcription of estrogen, androgen and aryl hydrocarbon receptor responsive genes in human breast cancer cells

Triclocarban (TCC) is an antimicrobial agent that is used in detergents, soaps and other personal hygiene products. Similarly to triclosan the widespread use of TCC has raised concerns about its endocrine potential. In luciferase-based reporter assays TCC has been shown to enhance estrogenic and androgenic activities following cellular coexposure with estrogen or dihydrotestosterone, respectively. The present study demonstrates that although coexposure with TCC enhances the estrogenic and androgenic readout of luciferase-based reporter cell lines such as HeLa9908 and MDA-kb2, it fails to act as a xenoandrogen on transcriptional level, nor does it induce cell proliferation in the estrogen sensitive E-screen. In addition TCC did not alter the expression of estrogen responsive genes in human mammary carcinoma MCF-7 cells exposed to 17β-estradiol, bisphenol A, butylparaben or genistein.However, TCC was shown to interfere with the regulon of the aryl hydrocarbon receptor (AhR) as TCC showed a costimulatory effect on transcription of CYP1A1 and CYP1B1, effectively lowering the transcriptional threshold for both genes in the presence of estrogens. It thus seems, that while the induction of the respective luciferase reporter assays by TCC is an unspecific false positive signal caused by luciferase stabilisation, TCC has the potential to interfere with the regulatory crosstalk of the estrogen receptor (ER) and the AhR regulon.

Calpain 2 Regulates Akt-FoxO-p27Kip1 Protein Signaling Pathway in Mammary Carcinoma

Calpain 2 Regulates Akt-FoxO-p27Kip1 Protein Signaling Pathway in Mammary Carcinoma

Effect of xanthopterin and isoxanthopterin on nitric oxide production by a RAW264.7 cell line

The pteridines xanthopterin (2‐amino‐4,6(3H,5H)‐pteridinedione) and isoxanthopterin (2‐amino‐4,7(3H,8H)‐pteridinedione) are products of the degradation of tetrahydrobiopterin, a coenzyme used by aryl amino acid hydroxylases, glyceryl ether monooxidase and nitric oxide synthases. These pteridines have cytotoxic effects on a number of cell lines including human mammary carcinoma MCF‐7 cell lines (Lord et al 2005, Cancer Lett. 222, 119). We wished to test the possibility that the pteridines could affect the activity of a nitric acid synthase. Accordingly, we performed experiments in which xanthopterin and isoxanthopterin were tested for their effect on nitric oxide (NO) production by a RAW264.7 mouse macrophage cell line with the resultant nitrite detected by the Griess assay. Both pteridines showed a dose‐dependent reduction of nitric oxide production with respect to controls. Whether this lowering of nitric oxide concentrations is due to inhibition of the inducible nitric oxide synthase will have to be examined. Furthermore, this finding may be significant since nitric oxide affects apoptosis (Brüne 2003, Cell Death and Differentiation 10, 864) and because of the well‐recognized association between chronic inflammation, cell proliferation, cancer and other diseases (Korhonen et al 2005 Current Drug Targets – Inflammation and Allergy 4, 471).

Xanthopterin‐induced apoptosis in leukemic cell lines

The pteridines xanthopterin (2‐amino‐4,6(3H,5H)‐pteridinedione) and isoxanthopterin (2‐amino‐4,7(3H,8H)‐pteridinedione) exhibit anticancer effects in mice and cytotoxicity in confluent human mammary carcinoma MCF7 cells and other transformed cell lines (Lord et al, Cancer Lett. 2005, 222, 119). We wished to study the effects of these pteridines in additional cell lines in an attempt to understand the mechanism of their cytotoxicity. We now report that xanthopterin shows a dose‐dependent cytotoxic effect on Jurkat cells as shown by the MTT assay for cellular viability (Malich et al, Toxicology 1997, 124, 179). Xanthopterin and, to a much less extent, isoxanthopterin induce apoptotic and necrotic‐like morphology in Jurkat T, 769‐P and EL‐4, but not K‐562, cell lines. Dose response curves and cytofluorometric analysis show that the two pteridines in a time and concentration‐dependent manner decrease Jurkat cell viability by inducing caspase 6 activity and rapid cellular disorganization, nuclear condensation, and fragmentation. This suggests that xanthopterin may have some potential as an apoptosis‐inducing agent in leukemia cells (Korhonen et al 2005 Current Drug Targets – Inflammation and Allergy 4, 471).

Prevention of Doxorubicin Cardiopathic Changes by a Benzyl Styryl Sulfone in Mice

Cardiac toxicity is a major limitation in the use of doxorubicin (and related anthracyclins). ON 1910.Na (Estybon, Rogersitib, or 1910), a substituted benzyl styryl sulfone, is equally active as doxorubicin against MCF-7 human mammary carcinoma xenografted into nude mice. 1910 augments the antitumor activity of doxorubicin when given simultaneously. Furthermore, when given in combination, 1910 protects against cardiac weight loss and against morphological damage to cardiac tissues. Doxorubicin induces inactivation of glucose response protein 78 (GRP78), a principal chaperone that serves as the master regulator of the unfolded protein response (UPR). Inactivated GRP78 leads to an increase in misfolded proteins, endoplasmic reticulum (ER) stress, activation of UPR sensors, and increased CHOP expression. 1910 prevents the inactivation of GRP78 by doxorubicin, and the combination, while more active against the tumor, protects against cardiac weight loss.

Curcumin inhibits metastatic progression of breast cancer cell through suppression of urokinase-type plasminogen activator by NF-kappa B signaling pathways

Curcumin (1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione), is extracted from the plant Curcuma longa. It was recently reported for its anticancer effect on several types of cancer cells in vitro however, the molecular mechanisms of this anticancer effect are not fully understood. In the present study, we evaluated the effects of curcumin on human mammary epithelial carcinoma MCF-7 cells. Cells were treated with curcumin and examined for cell viability by MTT assay. The cells invasion was demonstrated by transwell assay. The binding activity of NF-κB to DNA was examined in nuclear extracts using Trans-AM NF-κB ELISA kit. Western blot was performed to detect the effect of curcumin on the expression of uPA. Our results showed that curcumin dose-dependently inhibited (P<0.05) the proliferation of MCF-7 cells. Meanwhile, the adhesion and invasion ability of MCF-7 cells were sharply inhibited when treated with different concentrations of curcumin. Curcumin also significantly decreased (P<0.05) the expression of uPA and NF-κB DNA binding activity, respectively. It is concluded that curcumin inhibits the adhesion and invasion of MCF-7 cells through down-regulating the protein expression of uPA via of NF-κB activation. Accordingly, the therapeutic potential of curcumin for breast cancer deserves further study.

The Effects of n-3 Fatty Acids and Bexarotene on Breast Cancer Cell Progression

Breast cancer cell growth can be inhibited in vivo by retinoid X receptor (RXR) specific retinoids. In both animal and cell culture studies, omega-3 fatty acids share growth regulatory effects similar to those of RXR specific retinoids (rexinoids). One synthetic rexinoid, bexarotene (LCD 1069, Targretin), is used clinically to treat cancer patients. Of concern is that some patients are unable to tolerate high doses of such treatment drugs. We hypothesized that n-3 fatty acids and bexarotene may work synergistically to slow breast cancer cell growth. To test our hypothesis, we used MCF-7 human mammary carcinoma cells and an in vitro cell culture model. We investigated the relationship between the omega-3 fatty acids docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) alone and in conjunction with bexarotene in slowing MCF-7 cell growth. Following a 72 hr incubation with the respective treatments, bexarotene enhanced cell growth (p < 0.05) while DHA showed a strong growth inhibitory effect which was not enhanced by the addition of bexarotene (p < 0.05). EPA alone was not effective in altering cell growth (p < 0.05). Interestingly, when combined with bexarotene, EPA was more effective at slowing cell growth than when cells received EPA alone. Thus, select omega-3 fatty acids alone are more effective than bexarotene in slowing MCF-7 cell progression. However, the use of the RXR-selective retinoids may enhance the growth regulatory mechanisms of the fatty acid EPA.

Abstract 5473: Antiproliferative and antimetastasic activity of a novel vasopressin V2 receptor peptide agonist in a breast cancer model

Abstract Desmopressin (1-deamino-8-D-arginine vasopressin) is a synthetic analog of vasopressin with antimetastatic properties. The molecule is a well known and safe hemostatic compound that acts as a selective agonist for the vasopressin V2 membrane receptor, which is expressed in endothelium and also in some tumor cells. Previous data revealed that perioperative administration of desmopressin can minimize the spread and survival of residual cancer cells. This cyclic nonapeptide was substituted in positions 4 and 5 searching for compounds with improved biological activity and half life. Such positions belong to the disulphide loop (between positions 1-6), which have a major interaction with its receptor. In this work, we evaluated the in vitro biological activity of a novel analog designated VQ (1-deamino-4-valine-5-glutamine-8-D-arginine vasopressin) in MCF7 human mammary carcinoma cells, as well as its in vivo antitumor action in combination with chemotherapy using the syngeneic F3II mammary carcinoma model in Balb/c mice. Because V2 receptor signaling has been associated with cytostatic effects, we have examined peptide ability to modify in vitro cell proliferation of MCF7 cells expressing V2 receptor. Incubation with VQ analog (100-1500 nM) during 72 h significantly reduced cell proliferation (p&amp;lt;0.001) showing a better performance than desmopressin at higher doses of 500-1500 nM (p&amp;lt;0.05). Inhibition of cell proliferation was associated with an increase of intracellular cAMP levels and this was correlated with PKA activation in MCF7 cells. A similar antiproliferative profile was obtained with loop tetrapeptides (aminoacid positions 2-5) at low doses (&amp;lt;500 nM), although cytostatic activity of tetrapeptides was lost at high concentrations. Three weekly i.v. doses of VQ (0.3 µg/kg/dose) reduced by 40% the subcutaneous tumor volume in mice implanted with F3II mammary carcinoma cells, while VQ treatment plus weekly i.p. cycles of carmustine (20 mg/kg/cycle) was even more effective (p&amp;lt;0.001). Furthermore, VQ treatment, either in combination or not with carmustine cycles, prevented lung metastatic progression in tumor-bearing mice. VQ also inhibited F3II lung colonization in the experimental metastasis assay. Our results indicate that the novel cyclic peptide analog VQ can exert a remarkable antitumor and antimetastatic effect in a preclinical model of breast carcinoma. Loop conformation of the peptide seems to be essential for interaction with V2 receptor and for the biological activity of the compound. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 5473.