monastrol and Breast-Neoplasms

Novel pyrimidinic selenoureas were synthesized and evaluated against tumour and normal cell lines. Among these, the compound named 3j initially showed relevant cytotoxicity and selectivity for tumour cells. Three analogues of 3j were designed and synthesized keeping in view the structural requirements of this compound. Almost all the tested compounds displayed considerable cytotoxicity. However, 8a, one of the 3j analogues, was shown to be highly selective and cytotoxic, especially for breast carcinoma cells (MCF-7) (IC

Topics: Antineoplastic Agents; Apoptosis; Breast Neoplasms; Cell Cycle Checkpoints; Cell Proliferation; DNA Damage; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Female; HeLa Cells; Humans; MCF-7 Cells; Molecular Structure; Organoselenium Compounds; Pyrimidines; Structure-Activity Relationship; Tumor Cells, Cultured; Urea

Circular RNAs (circRNAs), a class of endogenous RNAs, have emerged as an enigmatic class of genes. However, little is known about their value in the progression and chemoresistance of cancers. The present study sought to determine the expression profiles and potential modulatory role of circRNAs on breast cancer cell viability and monastrol resistance. Monastrol-resistant cell lines were established by exposing breast cancer cells to increasing concentrations of monastrol. A human circRNA microarray was used to search for dysregulated circRNAs in monastrol-resistant cells, then circRNA‑MTO1 (hsa‑circRNA-007874) was validated as a circRNA that exhibited elevated expression levels in monastrol-resistant cells. Mechanistic investigations suggested that upregulation of circRNA‑MTO1 suppressed cell viability, promoted monastrol-induced cell cytotoxicity and reversed monastrol resistance. Subsequently, Eg5 was identified as the functional target of circRNA‑MTO1, and MTO1 inhibited Eg5 protein level but not mRNA level. By treating with protein synthesis inhibitor cycloheximide (CHX), it was revealed that MTO1 did not affect the protein stability of Eg5. RNA-pull down experiments followed by mass spectrometry revealed that MTO1 interacted with tumor necrosis factor receptor associated factor 4 (TRAF4), and sequester TRAF4 from activating Eg5 translation, thereby inhibiting the Eg5 protein level. Taken together, the data reveal a regulatory mechanism by circRNA‑MTO1 to control cell viability and monastrol resistance in breast cancer cells.

Topics: Antimitotic Agents; Breast Neoplasms; Carrier Proteins; Cell Line, Tumor; Cell Survival; Cycloheximide; Down-Regulation; Drug Resistance, Neoplasm; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Humans; Kinesins; Oligonucleotide Array Sequence Analysis; Pyrimidines; RNA; RNA-Binding Proteins; RNA, Circular; RNA, Messenger; Signal Transduction; Thiones; TNF Receptor-Associated Factor 4; Up-Regulation

A novel series of hybrid analogues of monastrol-1,3,5-triazine were designed and developed via one-pot synthesis using Bi(NO

Topics: Antineoplastic Agents; Antioxidants; Breast Neoplasms; Catalysis; Cell Line, Tumor; Drug Design; Drug Discovery; ErbB Receptors; Female; Humans; Ligands; Molecular Docking Simulation; Phosphorylation; Pyrimidines; Solvents; Thiones; Triazines; Tumor Burden

Monastrol is an allosteric inhibitor of the mitotic kinesin Eg5 that exhibits an antiproliferative effect against several cell lines. We investigated the antiproliferative effect of monastrol on human breast adenocarcinoma cells (MCF-7) and mammary epithelial cells (HB4a, non-tumoral). Monastrol treatment decreased cell viability only in MCF-7 tumor cells. Real-time cell growth kinetic analysis showed a decrease in the proliferation of MCF-7 cells exposed to monastrol, while in the HB4a cells, only a concentration of 100 μM was able to induce this effect. In a cell cycle analysis, exposure of MCF-7 cells to monastrol led to an increased population of cells in both the G1 and G2/M phases. In HB4a cells, the proportion of cells in the G2/M phase was increased. Monastrol led to an increased mitotic index in both cell lines. Monastrol was not able to induce cell death by apoptosis in any of the cell lines studied. Gene expression analysis was performed to measure the mRNA levels of cell cycle genes, DNA damage indicator gene, and apoptotic related genes. Treatment with monastrol induced in MCF-7 cells a 5-fold increase in the mRNA levels of the CDKN1A gene, an inhibitor of CDKs related with cell cycle arrest in response a stress stimulus, and a 2-fold decrease in CDKN1C mRNA levels in HB4a cells. These results provide evidence that monastrol has a greater antiproliferative effect on MCF-7 tumor cells compared with non-tumor HB4a cells; however, no selective is observed.

Topics: Adenocarcinoma; Antineoplastic Agents; Breast Neoplasms; Cell Proliferation; Cell Survival; Cyclin-Dependent Kinase Inhibitor p57; Dose-Response Relationship, Drug; Female; G1 Phase Cell Cycle Checkpoints; G2 Phase Cell Cycle Checkpoints; Gene Expression Regulation, Neoplastic; Humans; Kinetics; Mammary Glands, Human; MCF-7 Cells; Mitotic Index; Pyrimidines; RNA, Messenger; Thiones

Development of new, targeted antibreast cancer drug which can treat both the hormone receptor (positive and negative) breast cancers is a very challenging task. The concept of molecular hybridization led us to discover a novel class of coumarin-monastrol hybrid, as a novel breast cancer agent which selectively induce apoptosis in both primary and metastatic breast cancer cell lines.

Topics: Antineoplastic Agents; Apoptosis; Breast Neoplasms; Cell Cycle; Cell Proliferation; Cell Survival; Coumarins; Dose-Response Relationship, Drug; Drug Discovery; Drug Screening Assays, Antitumor; Female; Humans; MCF-7 Cells; Molecular Structure; Pyrimidines; Structure-Activity Relationship; Thiones; Tumor Cells, Cultured

Microtubule-disturbing drugs inhibit lysosomal trafficking and induce lysosomal membrane permeabilization followed by cathepsin-dependent cell death. To identify specific trafficking-related proteins that control cell survival and lysosomal stability, we screened a molecular motor siRNA library in human MCF7 breast cancer cells. SiRNAs targeting four kinesins (KIF11/Eg5, KIF20A, KIF21A, KIF25), myosin 1G (MYO1G), myosin heavy chain 1 (MYH1) and tropomyosin 2 (TPM2) were identified as effective inducers of non-apoptotic cell death. The cell death induced by KIF11, KIF21A, KIF25, MYH1 or TPM2 siRNAs was preceded by lysosomal membrane permeabilization, and all identified siRNAs induced several changes in the endo-lysosomal compartment, i.e. increased lysosomal volume (KIF11, KIF20A, KIF25, MYO1G, MYH1), increased cysteine cathepsin activity (KIF20A, KIF25), altered lysosomal localization (KIF25, MYH1, TPM2), increased dextran accumulation (KIF20A), or reduced autophagic flux (MYO1G, MYH1). Importantly, all seven siRNAs also killed human cervix cancer (HeLa) and osteosarcoma (U-2-OS) cells and sensitized cancer cells to other lysosome-destabilizing treatments, i.e. photo-oxidation, siramesine, etoposide or cisplatin. Similarly to KIF11 siRNA, the KIF11 inhibitor monastrol induced lysosomal membrane permeabilization and sensitized several cancer cell lines to siramesine. While KIF11 inhibitors are under clinical development as mitotic blockers, our data reveal a new function for KIF11 in controlling lysosomal stability and introduce six other molecular motors as putative cancer drug targets.

Topics: Apoptosis; Autophagy; Breast Neoplasms; Cell Death; Cell Membrane Permeability; Cytoskeletal Proteins; Female; HeLa Cells; Humans; Kinesins; Lysosomes; Minor Histocompatibility Antigens; Myosins; Pyrimidines; RNA, Small Interfering; Thiones; Tropomyosin

A series of conformationally flexible and restricted dimers of monastrol as well as related dihydropyrimidones have been synthesized by employing one-pot Biginelli multicomponent reaction. These dimers have been evaluated for cytotoxic potency against selected human cancer cell lines and some of the compounds have exhibited more cytotoxic potency than the parent monastrol. Further, the DNA binding ability by thermal denaturation studies and antimicrobial activities of these compounds are also discussed.

Topics: Anti-Infective Agents; Antineoplastic Agents; Breast Neoplasms; Cell Line, Tumor; Colonic Neoplasms; Differential Thermal Analysis; Dimerization; DNA; Drug Screening Assays, Antitumor; Female; Gram-Negative Bacteria; Gram-Positive Bacteria; Humans; Inhibitory Concentration 50; Lung Neoplasms; Microbial Sensitivity Tests; Molecular Conformation; Pyrimidines; Pyrimidinones; Skin Neoplasms; Structure-Activity Relationship; Thiones

HsEg5 (Eg5) is a kinesin required for proper execution of mitosis. Several compounds that specifically block Eg5 are in clinical development and have the potential to be used in the treatment of breast cancer. In this study, we investigated the interaction between Eg5 and estrogen receptor signaling. We observed decreased Eg5 expression after treatment of estrogen receptor-positive human breast cancer MCF-7 cells with the estrogen receptor downregulator fulvestrant. Downregulation of Eg5 expression in response to fulvestrant was also observed in another estrogen receptor-positive cell line ZR-75, but not in the estrogen receptor-negative breast cancer cell line MDA-231. Moreover, in MCF-7 cells previously arrested in the G0/G1 phase of the cell cycle by fulvestrant, addition of estrogen increased Eg5 expression. This upregulation correlated with progression through S-phase. Nevertheless, the effect of fulvestrant in Eg5 expression could not be explained solely by cell cycle arrest, because treatments that blocked cell cycle progression did not consistently decrease Eg5 expression. Pharmacological inhibition of Eg5 function, with either S-trityl-L-cysteine or monastrol, prevented growth of estrogen-treated MCF-7 cells with an IC50 of 0.46 and 29.71 micromol/l, respectively. Simultaneous inhibition of estrogen receptor function with fulvestrant increased the IC50 for S-trityl-L-cysteine to 2.30 micromol/l and for monastrol to 112.69 micromol/l. Our results suggest that pharmacological inhibition of Eg5 may be an effective treatment for estrogen receptor-positive breast cancer, even without concomitant hormonal therapy.

Topics: Blotting, Western; Breast Neoplasms; Cell Cycle; Cell Line, Tumor; Cysteine; Dose-Response Relationship, Drug; Down-Regulation; Estradiol; Estrogen Antagonists; Estrogens; Female; Flow Cytometry; Fulvestrant; Humans; Inhibitory Concentration 50; Kinesins; Mitosis; Pyrimidines; Receptors, Estrogen; Signal Transduction; Thiones; Up-Regulation

A secondary ion mass spectrometry (SIMS) based isotopic imaging technique was used for studies of i/ total calcium stored in cancerous and normal cell lines and ii/ intracellular chemical composition (total K, Na, and Ca) in relation to DNA staining patterns in taxol-treated breast cancer cells. A Cameca IMS-3f ion microscope with 0.5 microm spatial resolution was used. Observations were made on frozen freeze-dried cells. In MCF-10A non-tumorigenic breast epithelial cells, the nucleus contained 0.6 +/- 0.10 mM and the cytoplasm 1.1 +/- 0.30 mM total calcium per unit volume (mean +/- S.D.). MCF-7 tumorigenic breast epithelial cells revealed an abnormal total calcium distribution. Their nuclei and cytoplasm were not significantly different in stored calcium concentrations (0.5 +/- 0.08 mM total calcium in the nucleus and 0.6 +/- 0.07 mM in the cytoplasm). Furthermore, in MCF-7 cells the cytoplasmic total calcium is significantly less than in MCF-10A cells. Both cell lines contained approximately 150 mM intracellular potassium and 13 mM sodium. As 80% of the cytoplasmic total calcium pool in MCF-10A cells could be released with thapsigargin, it is plausible that the calcium storage capacity of the endoplasmic reticulum in tumorigenic MCF-7 cells is compromised. Correlative SIMS and confocal laser scanning microscopy (CLSM) revealed an increase in intracellular sodium and a redistribution of calcium in taxol-arrested M-phase cells prior to any noticeable DNA fragmentation. This novel correlative approach opens new avenues of research for understanding intracellular ionic composition in relation to therapeutic cytotoxicity. Other valuable features of SIMS for cancer research shown in this study include subcellular imaging of calcium influx using 44Ca, 127I from iododeoxyuridine for S-phase recognition, and 19F from fluorinated deoxyglucose.

Topics: Animals; Breast; Breast Neoplasms; Calcium; Cations; Cell Cycle; Cell Death; Cell Line; Epithelial Cells; Female; Fluorine; Fluorodeoxyglucose F18; Freeze Drying; HeLa Cells; Humans; Kidney; Microscopy, Confocal; Pyrimidines; S Phase; Spectrometry, Mass, Secondary Ion; Swine; Thapsigargin; Thiones; Tumor Cells, Cultured