pyrimidinones and Breast-Neoplasms

Uridine phosphorylase (UPase) is an enzyme that converts the pyrimidine nucleoside uridine into uracil. Upon availability of ribose-1-phosphate, UPase can also catalyze the formation of nucleosides from uracil as well as from 5-fluorouracil, therefore involved in fluoropyrimidine metabolism. UPase gene expression is strictly controlled at the promoter level by oncogenes, tumor suppressor genes, and cytokines. UPase activity is usually elevated in various tumor tissues, including breast cancer, compared to matched normal tissues and this induction appears to contribute to the therapeutic efficacy of fluoropyrimidines in cancer patients. In this review, we will discuss in detail the role of UPase in the activation of fluoropyrimidines and its effect on the prognosis of breast cancer patients.

Topics: Animals; Antimetabolites, Antineoplastic; Biomarkers, Tumor; Breast Neoplasms; Capecitabine; Deoxycytidine; Enzyme Induction; Female; Floxuridine; Fluorouracil; Gene Expression Regulation; Humans; Mice; Prodrugs; Prognosis; Pyrimidinones; Treatment Outcome; Uridine Phosphorylase

Multiple mechanisms have been proposed by which tumors induce T cell apoptosis to circumvent tumor immune-surveillance. Although sarco/endoplasmic reticulum Ca(2+)-ATPase (SERCA) have long been known to regulate intracellular Ca(2+) homeostasis, few studies have examined the role of SERCA in processes of T lymphocyte survival and activation. In this context it remains largely unexplored as to how tumors jeopardize SERCA function to disable T cell-mediated anti-tumor immunity. Here, we show that human CD4(+) T cells in the presence of tumor conditions manifested an up-regulation of SERCA3 expression that resulted in development of endoplasmic reticulum stress leading to CD4(+) T cell apoptosis. Prostaglandin E(2) produced by the tumor cell plays a critical role in up-regulating SERCA3 by enhancing the binding of its transcription factor Sp1. Gene manipulation and pharmacological approaches further established that an increase in SERCA expression also resulted in subsequent inhibition of PKCα and -θ and retention of NFκB in the cytosol; however, down-modulation of SERCA3 expression by a dihydropyrimidone derivative, ethyl-4-(3-nitro)-phenyl-6-methyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5 carboxylate (nifetepimine), protected the CD4(+) T cells from tumor-induced apoptosis. In fact, nifetepimine-mediated restoration of PKC activity resulted in nuclear translocation of p65NFκB, thereby ensuring its survival. Studies further undertaken in a tumor-bearing mice model revalidated the immunoprotective role of nifetepimine. Our present study thus strongly suggests that imbalance in cellular calcium homeostasis is an important factor leading to CD4(+) T cell death during cancer and holds promise that nifetepimine may have the potential to be used as an immunorestoring agent in cancer bearers.

Topics: Animals; Breast Neoplasms; Calcium; CD4-Positive T-Lymphocytes; Cell Survival; Dinoprostone; Endoplasmic Reticulum Stress; Female; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Neoplastic; Humans; Immunologic Factors; Lymphocyte Activation; Male; Mice; Neoplasm Proteins; Neoplasm Transplantation; Protein Kinase C-alpha; Pyrimidinones; Sarcoplasmic Reticulum Calcium-Transporting ATPases; Sp1 Transcription Factor; Transplantation, Heterologous; Tumor Microenvironment; Up-Regulation

To investigate the efficacy of nucleosides as a prophylactic agent against reactivation of hepatitis B virus (HBV) in HBsAg-positive patients with non-hepatic tumors after chemotherapy.. Fifty-eight patients with non-hepatic tumors were divided into prevention group and control group. The patients of prevention group received nucleosides as a prophylactic agent before chemotherapy and were compared with the control ones about the clinical manifestation of HBV reactivation. Then, the patients of the control group were divided into three groups according to antiviral drugs, use or not and time of the use. The patients having HBV reactivation but never received nucleosides were included in the group A, the patients receiving nucleosides after having HBV reactivation were divided into the group B, and the patients receiving nucleosides before HBV reactivation were divided into the group C. The progression, prognosis and curative effect among the three groups were compared.. The rate of HBV reactivation, incidence of severe hepatitis, mortality rate of the control group (61.1%, 27.8%, 16.7%) were significantly higher than those of the prevention group (13.6%, 0, 0), and liver dysfunction was more serious than that in the prevention group. In the control group, all the 5 patients of group A died of liver failure. Of the 13 patients in the group B, 4 cases suffered from severe hepatitis and 1 of them died of the disease. Of the 18 patients in the group C, 4 cases suffered from HBV reactivation, but the clinical manifestation was milder than that of the group B.. Nucleosides can be used as a prophylactic measure to prevent HBV reactivation. If chemotherapy had begun, the use of nucleosides may reduce the risk of HBV reactivation. Even if patients had suffered from HBV reactivation, the use of nucleosides may still help the recovery of liver function and improve prognosis.

Topics: Adult; Antineoplastic Agents; Antiviral Agents; Breast Neoplasms; Female; Follow-Up Studies; Guanine; Hepatitis B; Hepatitis B Surface Antigens; Hepatitis B virus; Humans; Lamivudine; Lung Neoplasms; Lymphoma; Male; Middle Aged; Nucleosides; Pyrimidinones; Retrospective Studies; Telbivudine; Thymidine; Virus Activation

Malignant adenomyoepithelioma (AME) of the breast is an exceptionally rare form of breast cancer, with a significant metastatic potential. Chemotherapy has been used in the management of advanced AME patients, however the majority of treatments are not effective. Recent studies report recurrent mutations in the HRAS Q61 hotspot in small series of AMEs, but there are no preclinical or clinical data showing H-Ras protein as a potential therapeutic target in malignant AMEs. We performed targeted sequencing of tumours' samples from new series of 13 AMEs, including 9 benign and 4 malignant forms. Samples from the breast tumour and the matched axillary metastasis of one malignant HRAS mutated AME were engrafted and two patient-derived xenografts (PDX) were established that reproduced the typical AME morphology. The metastasis-derived PDX was treated in vivo by different chemotherapies and a combination of MEK and BRAF inhibitors (trametinib and dabrafenib). All malignant AMEs presented a recurrent mutation in the HRAS G13R or G12S hotspot. Mutation of PIK3CA were found in both benign and malignant AMEs, while AKT1 mutations were restricted to benign AMEs. Treatment of the PDX by the MEK inhibitor trametinib, resulted in a marked anti-tumor activity, in contrast to the BRAF inhibitor and the different chemotherapies that were ineffective. Overall, these findings further expand on the genetic features of AMEs and suggest that patients carrying advanced HRAS-mutated AMEs could potentially be treated with MEK inhibitors.

Topics: Adenomyoepithelioma; Aged; Aged, 80 and over; Antineoplastic Agents; Breast; Breast Neoplasms; Drug Resistance, Neoplasm; Female; Humans; Imidazoles; Middle Aged; Oximes; Point Mutation; Protein Kinase Inhibitors; Proto-Oncogene Proteins p21(ras); Pyridones; Pyrimidinones

Auranofin is a gold complex used as an anti-rheumatic agent and may act as a potent anticancer drug against breast tumors. Trametinib is a specific mitogen-activated protein kinase inhibitor, approved for the treatment of metastatic melanoma. The aim of this study was to examine the synergistic effects of auranofin and trametinib on apoptosis in MCF-7 human breast cancer cells. The combination treatment inhibited cancer cell proliferation and induced cell cycle arrest at the sub-G1 phase and apoptosis via poly (ADP-ribose) polymerase cleavage and caspase-3/7 activation. It is noteworthy that this treatment significantly increased p38 mitogen-activated protein kinase (MAPK) phosphorylation to induce mitochondrial stress, subsequently promoting cancer cell apoptosis through release of apoptosis-inducing factor. Further data demonstrated that combined treatment significantly induced increase in nuclear translocation of AIF. These results indicated that activation of the p38 MAPK signaling pathway and mitochondrial apoptosis may contribute to the synergistic consequences in MCF-7 cells. Collectively, our data demonstrated that combined treatment with auranofin and trametinib exhibited synergistic breast cancer cell death and this combination might be utilized as a novel therapeutic strategy for breast cancer.

Topics: Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Auranofin; Breast Neoplasms; Cell Proliferation; Female; Humans; MCF-7 Cells; p38 Mitogen-Activated Protein Kinases; Pyridones; Pyrimidinones

Luminal B breast tumors are more aggressive estrogen receptor-positive (ER. We performed large-scale RNA sequencing analysis to identify chimerical transcripts preferentially expressed in luminal B breast cancer. The lead candidate was validated by reverse transcription PCR in breast cancer tissues. The effects of inducible ectopic expression or genetic silencing were assessed by phenotypic assays such as MTS, transwell, and transendothelial migration assays, and by clonogenic assays to assess MEK inhibitor sensitivity. Subcellular fractionation, Western blots, and immunoprecipitation were performed to characterize the protein products and elucidate the engaged mechanisms.. This discovery sheds light on a new area of molecular pathobiology of luminal B tumors and implies potential new therapeutic opportunities for more aggressive breast tumors overexpressing this fusion.

Topics: Breast; Breast Neoplasms; Cell Line, Tumor; Datasets as Topic; DNA-Binding Proteins; Drug Resistance, Neoplasm; Dyrk Kinases; Female; Gene Expression Regulation, Neoplastic; Gene Knockdown Techniques; Humans; MAP Kinase Signaling System; Mitogen-Activated Protein Kinase Kinases; Oncogene Proteins, Fusion; Protein Serine-Threonine Kinases; Protein-Tyrosine Kinases; Pyridones; Pyrimidinones; RNA-Binding Proteins; RNA-Seq

Breast cancer (BC) is the leading cause of death in women all over the world. Currently, combined chemotherapy with two or more agents is considered a promising anti-cancer tool to achieve better therapeutic response and to reduce therapy-related side effects. In our study, we demonstrated an antagonistic effect of cytostatic agent-cisplatin (CDDP) and histone deacetylase inhibitor: cambinol (CAM) for breast cancer cell lines with different phenotypes: estrogen receptor positive (MCF7, T47D) and triple negative (MDA-MB-231, MDA-MB-468). The type of pharmacological interaction was assessed by an isobolographic analysis. Our results showed that both agents used separately induced cell apoptosis; however, applying them in combination ameliorated antiproliferative effect for all BC cell lines indicating antagonistic interaction. Cell cycle analysis showed that CAM abolished cell cycle arrest in S phase, which was induced by CDDP. Additionally, CAM increased cell proliferation compared to CDDP used alone. Our data indicate that CAM and CDDP used in combination produce antagonistic interaction, which could inhibit anti-cancer treatment efficacy, showing importance of preclinical testing.

Topics: Apoptosis; Breast Neoplasms; Cell Cycle; Cisplatin; Drug Antagonism; Female; Histone Deacetylase Inhibitors; Humans; MCF-7 Cells; Models, Biological; Naphthalenes; Pyrimidinones

Although trastuzumab has greatly improved the outcome of HER2-positive breast cancer, the emergence of resistance hampers its clinical benefits. Trastuzumab resistance is a multi-factorial consequence predominantly due to presence of cancer stem-like cells (CSCs). AZD1775, a potent anti-cancer agent targeting WEE1 kinase to drive tumor cells with DNA damage to premature mitosis, has previously shown high efficacies when targeting different cancers with a well-tolerated cytotoxic profile, but has not been evaluated in trastuzumab-resistant (TrR) breast cancer. We sought to investigate the effect of AZD1775 on cancer stem-like cell (CSC) properties, apoptosis, cell cycle regulation in TrR breast cancer. Our study for the first time demonstrated that AZD1775 induces apoptosis and arrests TrR cells at G2/M phase. More importantly, AZD1775 effectively targeted CSC properties by suppressing MUC1 expression levels. AZD1775 administration also induced apoptosis in our in-house patient-derived tumor cell line at passage 0, implying its significant clinical relevance. These findings highlight the potential clinical application of AZD1775 in overcoming trastuzumab resistance in breast cancer.

Topics: Animals; Breast Neoplasms; Cell Cycle Proteins; Cell Line, Tumor; Cell Proliferation; Drug Resistance, Neoplasm; Female; Gene Expression Regulation, Neoplastic; Gene Silencing; Heterografts; Humans; Mice; Neoplastic Stem Cells; Protein-Tyrosine Kinases; Pyrazoles; Pyrimidinones; Receptor, ErbB-2; Trastuzumab

A multicomponent synthesis was empolyed for the synthesis of ethyl 2-amino-4,5,6,7-tetrahydrobenzo[

Topics: Alkylation; Antineoplastic Agents; Apoptosis; Breast Neoplasms; Cell Line, Tumor; Cell Proliferation; Hep G2 Cells; Humans; MCF-7 Cells; Pyrimidinones; Structure-Activity Relationship; Thiophenes

Monocarboxylate transporter 1 (MCT1) represents a potential therapeutic target in cancer. The objective of this study was to determine the efficacy of AZD3965 (a specific inhibitor of MCT1) and α-cyano-4-hydroxycinnamic acid (CHC, a nonspecific inhibitor of MCTs) in the murine 4T1 tumor model of triple-negative breast cancer (TNBC). Expression of MCT1 and MCT4 in 4T1 and mouse mammary epithelial cells were determined by Western blot. Inhibition of MCT1-mediated L-lactate uptake and cellular proliferation by AZD3965 and CHC was determined. Mice bearing 4T1 breast tumors were treated with AZD3965 100 mg/kg i.p. twice-daily or CHC 200 mg/kg i.p. once-daily. Tumor growth, metastasis, intra-tumor lactate concentration, immune function, tumor MCT expression, and concentration-effect relationships were determined. AZD3965 and CHC inhibited cell growth and L-lactate uptake in 4T1 cells. AZD3965 treatment resulted in trough plasma and tumor concentrations of 29.1 ± 13.9 and 1670 ± 946 nM, respectively. AZD3965 decreased the tumor proliferation biomarker Ki67 expression, increased intra-tumor lactate concentration, and decreased tumor volume, although tumor weight was not different from untreated controls. CHC had no effect on tumor volume and weight, or intra-tumor lactate concentration. AZD3965 treatment reduced the blood leukocyte count and spleen weight and increased lung metastasis, while CHC did not. These findings indicate AZD3965 is a potent MCT1 inhibitor that accumulates to high concentrations in 4T1 xenograft tumors, where it increases tumor lactate concentrations and produces beneficial effects on markers of TNBC; however, overall effects on tumor growth were minimal and lung metastases increased.

Topics: Animals; Breast Neoplasms; Cell Line, Tumor; Coumaric Acids; Dose-Response Relationship, Drug; Female; Lung Neoplasms; Mice; Mice, Inbred BALB C; Monocarboxylic Acid Transporters; Pyrimidinones; Symporters; Thiophenes; Treatment Outcome; Tumor Burden; Xenograft Model Antitumor Assays

Inhibition of WEE1 kinase by AZD1775 has shown promising results in clinical cancer trials, but markers predicting AZD1775 response are lacking. Here we analysed AZD1775 response in a panel of human breast cancer (BC) cell lines by global proteome/transcriptome profiling and identified two groups of basal-like BC (BLBCs): 'PTEN low' BLBCs were highly sensitive to AZD1775 and failed to recover following removal of AZD1775, while 'PTEN high' BLBCs recovered. AZD1775 induced phosphorylation of DNA-PK, protecting cells from replication-associated DNA damage and promoting cellular recovery. Deletion of DNA-PK or PTEN, or inhibition of DNA-PK sensitized recovering BLBCs to AZD1775 by abrogating replication arrest, allowing replication despite DNA damage. This was linked to reduced CHK1 activation, increased cyclin E levels and apoptosis. In conclusion, we identified PTEN and DNA-PK as essential regulators of replication checkpoint arrest in response to AZD1775 and defined PTEN as a promising biomarker for efficient WEE1 cancer therapy.

Topics: Antineoplastic Agents; Breast Neoplasms; Cell Cycle Proteins; Cell Line, Tumor; DNA-Activated Protein Kinase; Female; Gene Expression Profiling; Humans; Protein-Tyrosine Kinases; Proteome; PTEN Phosphohydrolase; Pyrazoles; Pyrimidinones

As standard treatments for cancer, DNA-damaging chemotherapeutic agents and irradiation therapy improve survival in patients with various cancers. Wee1, a kinase associated with the cell cycle, causes G2/M cell cycle arrest to allow repair of injured DNA in cancer cells, and a Wee1 inhibitor has been confirmed to lead to apoptosis in cancer cells. Recently, there has been renewed interest in exploring the immune environment which plays a significant role in tumour suppression. A Wee1 inhibitor combined with radiotherapy has been tested in lung, pancreatic, and prostate cancer and melanoma in vivo or in vitro. There is still no research evaluating the immunoregulatory effects of AZD1775 plus high-dose irradiation (IR) in vivo. T cell killing and CD8+ T cell depletion assays demonstrated that the combination of AZD1775 and IR delayed tumour growth in breast cancer mouse models. Additionally, combination treatment also suppressed the expression of PD-L1, a co-inhibitor, through the STAT3-IRF1 axis. The importance and originality of this study are that it explores the internal and external mechanisms of AZD1775 combined with a single high dose of IR and provides a rationale for applying the combination therapy described above in a clinical trial.

Topics: Animals; Breast Neoplasms; CD8-Positive T-Lymphocytes; Cell Cycle Proteins; Cell Line, Tumor; Combined Modality Therapy; Dendritic Cells; Disease Models, Animal; Enzyme Inhibitors; Female; Humans; Mice; Mice, Inbred BALB C; Protein-Tyrosine Kinases; Pyrazoles; Pyrimidinones; Radiation, Ionizing

Adavosertib (also known as AZD1775 or MK1775) is a small-molecule inhibitor of the protein kinase Wee1, with single-agent activity in multiple solid tumors, including sarcoma, glioblastoma, and head and neck cancer. Adavosertib also shows promising results in combination with genotoxic agents such as ionizing radiation or chemotherapy. Previous studies have investigated molecular mechanisms of primary resistance to Wee1 inhibition. Here, we investigated mechanisms of acquired resistance to Wee1 inhibition, focusing on the role of the Wee1-related kinase Myt1. Myt1 and Wee1 kinases were both capable of phosphorylating and inhibiting Cdk1/cyclin B, the key enzymatic complex required for mitosis, demonstrating their functional redundancy. Ectopic activation of Cdk1 induced aberrant mitosis and cell death by mitotic catastrophe. Cancer cells with intrinsic adavosertib resistance had higher levels of Myt1 compared with sensitive cells. Furthermore, cancer cells that acquired resistance following short-term adavosertib treatment had higher levels of Myt1 compared with mock-treated cells. Downregulating Myt1 enhanced ectopic Cdk1 activity and restored sensitivity to adavosertib. These data demonstrate that upregulating Myt1 is a mechanism by which cancer cells acquire resistance to adavosertib. SIGNIFICANCE: Myt1 is a candidate predictive biomarker of acquired resistance to the Wee1 kinase inhibitor adavosertib.

Topics: Animals; Breast; Breast Neoplasms; CDC2 Protein Kinase; Cell Cycle Proteins; Cell Line, Tumor; Disease-Free Survival; Drug Resistance, Neoplasm; Female; Gene Expression Regulation, Neoplastic; Humans; Membrane Proteins; Mice; Protein Serine-Threonine Kinases; Protein-Tyrosine Kinases; Pyrazoles; Pyrimidinones; RNA, Small Interfering; Up-Regulation; Xenograft Model Antitumor Assays

AR-C155858 and AZD3965, pyrrole pyrimidine derivatives, represent potent monocarboxylate transporter 1 (MCT1) inhibitors, with potential immunomodulatory and chemotherapeutic properties. Currently, there is limited information on the inhibitory properties of this new class of MCT1 inhibitors. The purpose of this study was to characterize the concentration- and time-dependent inhibition of L-lactate transport and the membrane permeability properties of AR-C155858 and AZD3965 in the murine 4T1 breast tumor cells that express MCT1. Our results demonstrated time-dependent inhibition of L-lactate uptake by AR-C155858 and AZD3965 with maximal inhibition occurring after a 5-min pre-incubation period and prolonged inhibition. Following removal of AR-C155858 or AZD3965 from the incubation buffer, inhibition of L-lactate uptake was only fully reversed after 3 and 12 h, respectively, indicating that these inhibitors are slowly reversible. The uptake of AR-C155858 was concentration-dependent in 4T1 cells, whereas the uptake of AZD3965 exhibited no concentration dependence over the range of concentrations examined. The uptake kinetics of AR-C155858 was best fitted to a Michaelis-Menten equation with a diffusional clearance component, P (K

Topics: Animals; Breast Neoplasms; Cell Line, Tumor; Coumaric Acids; Drug Screening Assays, Antitumor; Female; Humans; Hydrogen-Ion Concentration; Lactic Acid; Mice; Monocarboxylic Acid Transporters; Pyrimidinones; Symporters; Thiophenes; Uracil

AZD3965, a pyrole pyrimidine derivative, is a potent and orally bioavailable inhibitor of monocarboxylate transporter 1 (MCT1), currently in a Phase I clinical trial in UK for lymphomas and solid tumors. There is currently no published assay for AZD3965. The objectives of this study were to develop and validate a LC/MS/MS assay for quantifying AZD3965 in mouse plasma and tumor tissue. Protein precipitation with 0.1% formic acid in acetonitrile was used for sample preparation. Chromatographic separation was achieved on a C18 column followed by tandem mass spectrometry detection in multiple reaction monitoring mode with utilizing Atmospheric Pressure Chemical Ionization. AR-C155858 was used as the internal standard. The inter-day and intra-day precision and accuracy of quality control samples evaluated in plasma and tumor tissue were less than ±7% of the nominal concentrations. The extraction recovery, matrix effect and stability values were all within acceptable levels. Sample dilution integrity, accessed by diluting plasma spiked with AZD3965 10-fold with blank plasma, was 101%. The lower limit of quantification (LLOQ) and upper limit of quantification (ULOQ) were 0.15 ng/mL and 12 μg/mL, respectively, in plasma. The assay of AZD3965 in tumor tissue was also validated with good precision and accuracy. The LLOQ was 0.15 ng/mL in tumor tissue. This assay was successfully applied to pharmacokinetic and murine 4T1 breast tumor xenograft studies of AZD3965 in mice.

Topics: Acetonitriles; Animals; Atmospheric Pressure; Breast Neoplasms; Cell Line, Tumor; Chromatography, Liquid; Female; Heterografts; Mice; Plasma; Pyrimidines; Pyrimidinones; Reproducibility of Results; Tandem Mass Spectrometry; Thiophenes; Uracil

The CDC7 kinase, by phosphorylating the MCM DNA helicase, is a key switch for DNA replication initiation. ATP competitive CDC7 inhibitors are being developed as potential anticancer agents; however how human cells respond to the selective pharmacological inhibition of this kinase is controversial and not understood. Here we have characterized the mode of action of the two widely used CDC7 inhibitors, PHA-767491 and XL-413, which have become important tool compounds to explore the kinase's cellular functions. We have used a chemical genetics approach to further characterize pharmacological CDC7 inhibition and CRISPR/CAS9 technology to assess the requirement for kinase activity for cell proliferation. We show that, in human breast cells, CDC7 is essential and that CDC7 kinase activity is formally required for proliferation. However, full and sustained inhibition of the kinase, which is required to block the cell-cycle progression with ATP competitor compounds, is problematic to achieve. We establish that MCM2 phosphorylation is highly sensitive to CDC7 inhibition and, as a biomarker, it lacks in dynamic range since it is easily lost at concentrations of inhibitors that only mildly affect DNA synthesis. Furthermore, we find that the cellular effects of selective CDC7 inhibitors can be altered by the concomitant inhibition of cell-cycle and transcriptional CDKs. This work shows that DNA replication and cell proliferation can occur with reduced CDC7 activity for at least 5 days and that the bulk of DNA synthesis is not tightly coupled to MCM2 phosphorylation and provides guidance for the development of next generation CDC7 inhibitors.

Topics: Adenosine Triphosphate; Binding, Competitive; Breast Neoplasms; Cell Cycle; Cell Line, Tumor; Cell Proliferation; DNA Replication; Female; Humans; Phosphorylation; Piperidones; Protein Serine-Threonine Kinases; Pyrimidinones; Pyrroles

Targeting of human cancer stem cells (CSCs) requires the identification of vulnerabilities unique to CSCs versus healthy resident stem cells (SCs). Unfortunately, dysregulated pathways that support transformed CSCs, such as Wnt/β-catenin signaling, are also critical regulators of healthy SCs. Using the ICG-001 and CWP family of small molecules, we reveal Sam68 as a previously unappreciated modulator of Wnt/β-catenin signaling within CSCs. Disruption of CBP-β-catenin interaction via ICG-001/CWP induces the formation of a Sam68-CBP complex in CSCs that alters Wnt signaling toward apoptosis and differentiation induction. Our study identifies Sam68 as a regulator of human CSC vulnerability.

Topics: Adaptor Proteins, Signal Transducing; Adult; Aged; Animals; Apoptosis; Azabicyclo Compounds; beta Catenin; Breast Neoplasms; Bridged Bicyclo Compounds, Heterocyclic; Cell Differentiation; Cells, Cultured; Colonic Neoplasms; DNA-Binding Proteins; Female; Humans; Leukemia, Myeloid, Acute; Male; Mice; Mice, Inbred NOD; Middle Aged; Neoplastic Stem Cells; Organophosphates; Peptide Fragments; Proto-Oncogene Proteins c-myc; Pyrimidinones; RNA Interference; RNA-Binding Proteins; Sialoglycoproteins; Sumoylation; Transcriptome; Wnt Signaling Pathway

The presence of tumor-infiltrating lymphocytes in triple-negative breast cancers is correlated with improved outcomes. Ras/MAPK pathway activation is associated with significantly lower levels of tumor-infiltrating lymphocytes in triple-negative breast cancers and while MEK inhibition can promote recruitment of tumor-infiltrating lymphocytes to the tumor, here we show that MEK inhibition adversely affects early onset T-cell effector function. We show that α-4-1BB and α-OX-40 T-cell agonist antibodies can rescue the adverse effects of MEK inhibition on T cells in both mouse and human T cells, which results in augmented anti-tumor effects in vivo. This effect is dependent upon increased downstream p38/JNK pathway activation. Taken together, our data suggest that although Ras/MAPK pathway inhibition can increase tumor immunogenicity, the negative impact on T-cell activity is functionally important. This undesirable impact is effectively prevented by combination with T-cell immune agonist immunotherapies resulting in superior therapeutic efficacy.MEK inhibition in breast cancer is associated with increased tumour infiltrating lymphocytes (TILs), however, MAPK activity is required for T cells function. Here the authors show that TILs activity following MEK inhibition can be enhanced by agonist immunotherapy resulting in synergic therapeutic effects.

Topics: 4-1BB Ligand; Animals; Breast Neoplasms; Cell Line, Tumor; Cell Proliferation; Female; Humans; Immunotherapy; Lymphocytes, Tumor-Infiltrating; Mammary Neoplasms, Animal; MAP Kinase Kinase 1; MAP Kinase Kinase 2; MAP Kinase Signaling System; Mice; OX40 Ligand; Protein Kinase Inhibitors; Pyridones; Pyrimidinones; T-Lymphocyte Subsets; T-Lymphocytes; Triple Negative Breast Neoplasms

Malignant melanomas presenting with unknown primaries are uncommon. In the majority of cases metastases of occult melanoma were detected in skin or in lymph nodes. Melanoma can rarely occur as a primary or metastatic intramammary tumor.. We report the case of a 58-year-old Caucasian woman who came to our department with a voluminous mass in her right breast. Histopathological examination found metastasis of epithelioid melanoma with unknown primary lesion. Our patient underwent a radical enlarged mastectomy, but due to the extension a radical removal was not possible.. In 2.2% of cases, melanoma may present with a metastasis without an identifiable primary lesion; this case should be considered a stage IV melanoma (Tx; N1; M1) due to the extension of the lesion and the infiltration of adjacent structures.. In literature, the presence of a breast metastasis of melanoma with unknown primary origin was reported just in one case. The execution of histopathological analysis is mandatory for a correct differential diagnosis with primary carcinoma of the breast. Palliative metastasectomy should be discussed with multidisciplinary melanoma board.. Breast metastases, Metastatic melanoma, Unknown primary site.. Il melanoma maligno, nel 2.2% dei casi, si presenta in forma metastatica con localizzazione primaria non identificabile, si parla in questi casi di metastasi da melanoma primitivo occulto. Le metastasi di melanoma sono localizzate più frequentemente a livello cutaneo e linfonodale, mentre la presenza di metastasi mammarie è poco frequente. In letteratura è riportato un solo caso di metastasi intramammarie da melanoma primitivo occulto, in questo lavoro ne presentiamo un nuovo caso. Si tratta di una donna caucasica di 58 anni che è giunta alla nostra attenzione per una voluminosa massa a livello della mammella destra. L’esame istologico della lesione ha diagnosticato la presenza di metastasi mammaria da melanoma cutaneo. La paziente è stata quindi sottoposta ad un accurato esame dermatologico, oftalmologico, pneumologico e gastroenterologico ma non è stata identificata la lesione primitiva. Si tratta di un caso molto particolare e di difficile gestione ed inquadramento terapeutico per le dimensioni della massa e l’estesa infiltrazione alla parete toracica anteriore. La paziente è stata sottoposta a mastectomia radicale allargata, ma a causa dell’estensione della lesione non è stata possibile un’escissione radicale. Sebbene la stadiazione del melanoma occulto sia difficile a causa dell’impossibilità di determinare se si tratti di metastasi regionali o a distanza, questo caso dovrebbe essere considerato uno stadio IV (Tx; N1; M1) per l’estensione e l’infiltrazione delle strutture adiacenti. Nei casi di metastasi intramammarie l’esame istopatologico è dirimente per una corretta diagnosi differenziale con il carcinoma mammario primitivo. La mastectomia palliativa dovrebbe essere attentamente valutata con un team multidisciplinare per la cura del melanoma.

Topics: Antineoplastic Combined Chemotherapy Protocols; Breast Neoplasms; Carcinoma, Ductal, Breast; Combined Modality Therapy; Diagnosis, Differential; Female; Humans; Imidazoles; Mastectomy; Melanoma; Middle Aged; Neoplasm Invasiveness; Neoplasm Staging; Neoplasms, Unknown Primary; Oximes; Palliative Care; Pyridones; Pyrimidinones

Monocarboxylate transporter 1 (MCT1) inhibition is thought to block tumor growth through disruption of lactate transport and glycolysis. Here, we show MCT1 inhibition impairs proliferation of glycolytic breast cancer cells co-expressing MCT1 and MCT4 via disruption of pyruvate rather than lactate export. MCT1 expression is elevated in glycolytic breast tumors, and high MCT1 expression predicts poor prognosis in breast and lung cancer patients. Acute MCT1 inhibition reduces pyruvate export but does not consistently alter lactate transport or glycolytic flux in breast cancer cells that co-express MCT1 and MCT4. Despite the lack of glycolysis impairment, MCT1 loss-of-function decreases breast cancer cell proliferation and blocks growth of mammary fat pad xenograft tumors. Our data suggest MCT1 expression is elevated in glycolytic cancers to promote pyruvate export that when inhibited, enhances oxidative metabolism and reduces proliferation. This study presents an alternative molecular consequence of MCT1 inhibitors, further supporting their use as anti-cancer therapeutics.

Topics: Animals; Antineoplastic Agents; Biological Transport; Breast Neoplasms; Cell Line, Tumor; Cell Proliferation; Citric Acid Cycle; Epithelial Cells; Female; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Glycolysis; Humans; Lung Neoplasms; Mice; Monocarboxylic Acid Transporters; Muscle Proteins; Oxidative Phosphorylation; Pyrimidinones; Pyruvic Acid; Signal Transduction; Symporters; Thiophenes; Tumor Burden; Xenograft Model Antitumor Assays

Breast cancer is one of the leading causes of death for women worldwide. Among various subtypes of breast cancer, human epidermal growth factor receptor 2 (HER2)-positive and phosphatase and tensin homolog (PTEN) loss breast cancer is a cause of great concern in terms of its resistance to HER2-targeted therapies and its poor prognosis. Phosphatidylinositol 3-kinase (PI3K)/AKT hyperphosphorylation is considered one of key mechanisms leading to this resistance, thus combination therapy of PI3K inhibitors and HER2 antibodies is promising for overcoming this problem, and more specific regimens should be designed in this age of precision medicine. In this study, we established an HER2-positive and PTEN loss cell line and confirmed it by western blot analysis. This cell line and its orthotopic xenograft models were exposed to p110α-specific inhibitor BYL719, p110β-specific inhibitor AZD6482, or pan-PI3K inhibitor BKM120, respectively, and the results showed sensitivity to both BYL719 and BKM120 but not AZD6482, which indicated a p110α-reliance for HER2-positive-PTEN-loss breast cancer. Then, the addition of BYL719 to HER2 antibody greatly reduced tumor growth both in vitro and in vivo, accompanied by inhibited PI3K effector phosphorylation. Therefore, our findings suggest that the combination of p110α-selective inhibitor BYL719 with HER2 antibody could be a potential strategy for more personalized treatment of HER2-posistive-PTEN-loss breast cancer; and in addition, the optimal schedule of this combination therapy needs to be further explored.

Topics: Aminopyridines; Animals; Antibodies; Breast Neoplasms; Cell Line, Tumor; Cell Proliferation; Cell Survival; Female; Humans; Lapatinib; Mice; Morpholines; ortho-Aminobenzoates; Phosphoinositide-3 Kinase Inhibitors; Phosphorylation; PTEN Phosphohydrolase; Pyrimidinones; Quinazolines; Receptor, ErbB-2; Thiazoles; Xenograft Model Antitumor Assays

BYL719, which selectively inhibits the alpha isoform of the phosphatidylinositol 3-kinase (PI3K) catalytic subunit (p110a), is currently in clinical trials for the treatment of solid tumors, especially luminal breast cancers with PIK3CA mutations and/or HER2 amplification. This study reveals that, even among these sensitive cancers, the initial efficacy of p110α inhibition is mitigated by rapid re-accumulation of the PI3K product PIP3 produced by the p110β isoform. Importantly, the reactivation of PI3K mediated by p110β does not invariably restore AKT phosphorylation, demonstrating the limitations of using phospho-AKT as a surrogate to measure PI3K activation. Consistently, we show that the addition of the p110β inhibitor to BYL719 prevents the PIP3 rebound and induces greater antitumor efficacy in HER2-amplified and PIK3CA mutant cancers.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Breast Neoplasms; Cell Line, Tumor; Class I Phosphatidylinositol 3-Kinases; Female; Gene Expression Regulation, Neoplastic; Humans; MCF-7 Cells; Mice; Mice, Nude; Neoplasm Transplantation; ortho-Aminobenzoates; Pyrimidinones; Receptor, ErbB-2; Signal Transduction; Thiazoles

In this issue of Cancer Cell, Schwartz and colleagues and Costa and colleagues demonstrate that inhibition of PI3Kα or PI3Kβ in cancer cells with hyperactivated PI3Kα or PI3Kβ, respectively, activates the other isoform, leading to a "rebound" of the PI3K activity through different compensation mechanisms.

Topics: Aniline Compounds; Animals; Antineoplastic Combined Chemotherapy Protocols; Breast Neoplasms; Chromones; Class I Phosphatidylinositol 3-Kinases; Female; Humans; Neoplasms; ortho-Aminobenzoates; Phosphoinositide-3 Kinase Inhibitors; Protein Kinase Inhibitors; PTEN Phosphohydrolase; Pyrimidinones; Thiazoles

ERBB2/HER2 belongs to the EGFR-family of receptor tyrosine kinases and its overexpression can promote tumor progression. Breast cancer patients with ERBB2 amplifications are currently treated with lapatinib, a small-molecule kinase inhibitor that specifically blocks EGFR/ERBB2 signaling. Here, we show that hypoxia, via HIF-1, induces resistance to lapatinib-mediated effects in ERBB2-expressing mammary epithelial and ERBB2-positive breast cancer cells. Lapatinib-mediated growth inhibition and apoptosis in three-dimensional (3D) cultures are decreased under hypoxic conditions. Hypoxia can maintain activation of signaling pathways downstream from ERBB2 including AKT and ERK in the presence of lapatinib. HIF-1 is both required and sufficient to induce lapatinib resistance as overexpression of stable HIF-1 in ERBB2-expressing cells blocks lapatinib-mediated effects and maintains ERBB2-downstream signaling under normoxic conditions. Under hypoxia, activation of ERK signaling is required for lapatinib resistance as treatment with MEK inhibitor trametinib reverses hypoxia-mediated lapatinib resistance. HIF-1 can bypass the lapatinib-treated inhibition of the ERK pathway via inhibition of the dual-specificity phosphatase 2 (DUSP2). Indeed, overexpression of DUSP2 in ErbB2-positve breast cancer cells reverses hypoxia-mediated lapatinib resistance. Thus, our results provide rationale for therapeutic evaluation of the treatment of hypoxic ERBB2 expressing breast tumors with a combination of lapatinib and MEK inhibitors.

Topics: Apoptosis; Breast Neoplasms; Cell Hypoxia; Cell Line; Cell Line, Tumor; Cell Proliferation; Drug Resistance, Neoplasm; Dual Specificity Phosphatase 2; Extracellular Signal-Regulated MAP Kinases; Female; Gene Expression Regulation, Neoplastic; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Immunoblotting; Kaplan-Meier Estimate; Lapatinib; Prognosis; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-akt; Pyridones; Pyrimidinones; Quinazolines; Receptor, ErbB-2; Reverse Transcriptase Polymerase Chain Reaction; RNA Interference; Signal Transduction

Overexpression of adenine triphosphate (ATP)-binding cassette (ABC) transporters is one of the main reasons of multidrug resistance (MDR) in cancer cells. Trametinib, a novel specific small-molecule mitogen-activated extracellular signal-regulated kinase (MEK) inhibitor, is currently used for the treatment of melanoma in clinic. In this study, we investigated the effect of trametinib on MDR mediated by ABC transporters. Trametinib significantly potentiated the effects of two ABCB1 substrates vincristine and doxorubicin on inhibition of growth, arrest of cell cycle and induction of apoptosis in cancer cells overexpressed ABCB1, but not ABCC1 and ABCG2. Furthermore, trametinib did not alter the sensitivity of non-ABCB1 substrate cisplatin. Mechanistically, trametinib potently blocked the drug-efflux activity of ABCB1 to increase the intracellular accumulation of rhodamine 123 and doxorubicin and stimulates the ATPase of ABCB1 without alteration of the expression of ABCB1. Importantly, trametinib remarkably enhanced the effect of vincristine against the xenografts of ABCB1-overexpressing cancer cells in nude mice. The predicted binding mode showed the hydrophobic interactions of trametinib within the large drug binding cavity of ABCB1. Consequently, our findings may have important implications for use of trametinib in combination therapy for cancer treatment.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; ATP Binding Cassette Transporter, Subfamily B; ATP Binding Cassette Transporter, Subfamily G, Member 2; ATP-Binding Cassette Transporters; Breast Neoplasms; Cell Cycle Checkpoints; Cell Line, Tumor; Cisplatin; Doxorubicin; Drug Resistance, Multiple; Drug Resistance, Neoplasm; Female; Humans; MCF-7 Cells; Mice; Mice, Inbred BALB C; Mice, Nude; Molecular Docking Simulation; Moths; Multidrug Resistance-Associated Proteins; Neoplasm Proteins; Pyridones; Pyrimidinones; Rhodamine 123; Vincristine; Xenograft Model Antitumor Assays

Rapamycin analogues have antitumor efficacy in several tumor types, however few patients demonstrate tumor regression. Thus, there is a pressing need for markers of intrinsic response/resistance and rational combination therapies. We hypothesized that epithelial-to-mesenchymal transition (EMT) confers rapamycin resistance. We found that the epithelial marker E-cadherin protein is higher in rapamycin sensitive (RS) cells and mesenchymal breast cancer cell lines selected by transcriptional EMT signatures are less sensitive to rapamycin. MCF7 cells, transfected with constitutively active mutant Snail, had increased rapamycin resistance (RR) compared to cells transfected with wild-type Snail. Conversely, we transfected two RR mesenchymal cell lines-ACHN and MDA-MB-231-with miR-200b/c or ZEB1 siRNA to promote mesenchymal-to-epithelial transition. This induced E-cadherin expression in both cell lines, and ACHN demonstrated a significant increase in RS. Treatment of ACHN and MDA-MB-231 with trametinib modulated EMT in ACHN cells in vitro. Treatment of MDA-MB-231 and ACHN xenografts with trametinib in combination with rapamycin resulted in significant growth inhibition in both but without an apparent effect on EMT. Future studies are needed to determine whether EMT status is predictive of sensitivity to rapalogs and to determine whether combination therapy with EMT modulating agents can enhance antitumor effects of PI3K/mTOR inhibitors.

Topics: Animals; Antigens, CD; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Breast Neoplasms; Cadherins; Cell Proliferation; Dose-Response Relationship, Drug; Drug Resistance, Neoplasm; Epithelial-Mesenchymal Transition; Extracellular Signal-Regulated MAP Kinases; Female; Gene Expression Regulation, Neoplastic; Histone Deacetylase Inhibitors; Homeodomain Proteins; Humans; MCF-7 Cells; Mice, Nude; MicroRNAs; Mitogen-Activated Protein Kinase Kinases; Mutation; Phosphorylation; Protein Kinase Inhibitors; Pyridones; Pyrimidinones; RNA Interference; Sirolimus; Snail Family Transcription Factors; Time Factors; TOR Serine-Threonine Kinases; Transcription Factors; Transfection; Tumor Burden; Xenograft Model Antitumor Assays; Zinc Finger E-box-Binding Homeobox 1

The Wnt signaling pathway is often chronically activated in diverse human tumors, and the Frizzled (FZD) family of receptors for Wnt ligands, are central to propagating oncogenic signals in a β-catenin-dependent and independent manner. SIRT1 is a class III histone deacetylase (HDAC) that deacetylates histone and non-histone proteins to regulate gene transcription and protein function. We previously demonstrated that SIRT1 loss of function led to a significant decrease in the levels of Dishevelled (Dvl) proteins. To further explore this connection between the sirtuins and components of the Wnt pathway, we analyzed sirtuin-mediated regulation of FZD proteins. Here we explore the contribution of sirtuin deacetylases in promoting constitutive Wnt pathway activation in breast cancer cells. We demonstrate that the use of small molecule inhibitors of SIRT1 and SIRT2, and siRNA specific to SIRT1, all reduce the levels of FZD7 mRNA. We further demonstrate that pharmacologic inhibition of SIRT1/2 causes a marked reduction in FZD7 protein levels. Additionally, we show that β-catenin and c-Jun occupy the 7 kb region upstream of the transcription start site of the FZD7 gene, and SIRT1 inhibition leads to a reduction in the occupancy of both β-catenin and c-Jun at points along this region. This work uncovers a new mechanism for the regulation of FZD7 and provides a critical new link between the sirtuins and FZD7, one of the earliest nodal points from which oncogenic Wnt signaling emanates. This study shows that inhibition of specific sirtuins may provide a unique strategy for inhibiting the constitutively active Wnt pathway at the level of the receptor.

Topics: beta Catenin; Breast Neoplasms; Cell Line, Tumor; Cell Movement; Cell Proliferation; Female; Frizzled Receptors; Gene Expression Regulation, Neoplastic; Gene Knockdown Techniques; Humans; Naphthalenes; Promoter Regions, Genetic; Protein Binding; Pyrimidinones; RNA, Messenger; Sirtuin 1; Sirtuin 2

Cellular signaling pathways involving mTOR, PI3K and ERK have dominated recent studies of breast cancer biology, and inhibitors of these pathways have formed a focus of numerous clinical trials. We have chosen trametinib, a drug targeting MEK in the ERK pathway, to address two questions. Firstly, does inhibition of a signaling pathway, as measured by protein phosphorylation, predict the antiproliferative activity of trametinib? Secondly, do inhibitors of the mTOR and PI3K pathways synergize with trametinib in their effects on cell proliferation? A panel of 30 human breast cancer cell lines was chosen to include lines that could be classified according to whether they were ER and PR positive, HER2 over-expressing, and "triple negative". Everolimus (targeting mTOR), NVP-BEZ235 and GSK2126458 (both targeting PI3K/mTOR) were chosen for combination experiments. Inhibition of cell proliferation was measured by IC50 values and pathway utilization was measured by phosphorylation of signaling kinases. Overall, no correlation was found between trametinib IC50 values and inhibition of ERK signaling. Inhibition of ERK phosphorylation was observed at trametinib concentrations not affecting proliferation, and sensitivity of cell proliferation to trametinib was found in cell lines with low ERK phosphorylation. Evidence was found for synergy between trametinib and either everolimus, NVP-BEZ235 or GSK2126458, but this was cell line specific. The results have implications for the clinical application of PI3K/mTOR and MEK inhibitors.

Topics: Antineoplastic Agents; Blotting, Western; Breast Neoplasms; Cell Line, Tumor; Cell Proliferation; Drug Synergism; Everolimus; Extracellular Signal-Regulated MAP Kinases; Female; Humans; Imidazoles; Inhibitory Concentration 50; MAP Kinase Signaling System; MCF-7 Cells; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Phosphorylation; Proto-Oncogene Proteins c-akt; Pyridazines; Pyridones; Pyrimidinones; Quinolines; Signal Transduction; Sirolimus; Sulfonamides; TOR Serine-Threonine Kinases

To explore the reversal effect of (- )-5-N-acetylardeemin on adriamycin resistance in multidrug-resistant cancer cells including human breast cancer cells MCF-7/Adr and human non-small cell lung cancer cells A549/Adr in vitro.. The multidrug-resistant cancer cells MCF-7/Adr, A549/Adr and their respective parental cells were treated with different concentrations of (- )-5-N-acetylardeemin and adriamycin individually or in combination. Cell death was detected based on the release of lactate dehydrogenase (LDH) using a cytotoxicity detection kit. Intracellular accumulation of adriamycin was measured by the detection of fluorescence intensity of cell lysates using microplate reader. The expression of P-glycoprotein (P-gp) was evaluated by Western blot.. (-)-5-N-acetylardeemin significantly reversed the adriamycin resistance in MCF-7/Adr and A549/ Adr in a dose-dependent manner, and the reversal folds were 10. 8 in MCF-7/Adr cells and 20.1 in A549/Adr cells with the treatment of 10 μmol/L (-)-5-N acetylardeemin. (- )-5-N-acetylardeemin also enhanced the sensitivity of parental MCF-7 and A549 cells to adriamycin. The fluorescence intensity in both MCF-7/Adr and A549/Adr cells, which reflected the intracellular accumulation of adriamycin, were significantly enhanced by ( -)5-N- acetylardeemin in a dose-dependent manner. The expressions of P-gp in MCF-7/Adr and A549/Adr cells were significantly inhibited by (- )-5-N-acetylardeemin.. (- )5-N-acetylardeemin could reverse the multidrug resistance in cancer cells through inhibiting the expression of P-gp and enhancing the intracellular accumulation of cytotoxic drug.

Topics: Antibiotics, Antineoplastic; ATP Binding Cassette Transporter, Subfamily B, Member 1; Breast Neoplasms; Carcinoma, Non-Small-Cell Lung; Cell Line, Tumor; Doxorubicin; Drug Resistance, Multiple; Drug Resistance, Neoplasm; Humans; Pyrimidinones

MEK1/2 inhibitors such as AZD6244 are in clinical trials for the treatment of multiple cancers, including breast cancer. Targeted kinase inhibition can induce compensatory kinome changes, rendering single therapeutic agents ineffective. To identify target proteins to be used in a combinatorial approach to inhibit tumor cell growth, we used a novel strategy that identified microRNAs (miRNAs) that synergized with AZD6244 to inhibit the viability of the claudin-low breast cancer cell line MDA-MB-231. Screening of a miRNA mimic library revealed the ability of miR-9-3p to significantly enhance AZD6244-induced extracellular signal-regulated kinase inhibition and growth arrest, while miR-9-3p had little effect on growth alone. Promoter methylation of mir-9 genes correlated with low expression of miR-9-3p in different breast cancer cell lines. Consistent with miR-9-3p having synthetic enhancer tumor suppressor characteristics, miR-9-3p expression in combination with MEK inhibitor caused a sustained loss of c-MYC expression and growth inhibition. The β1 integrin gene (ITGB1) was identified as a new miR-9-3p target, and the growth inhibition seen with small interfering RNA knockdown or antibody blocking of ITGB1 in combination with MEK inhibitor phenocopied the growth inhibition seen with miR-9-3p plus AZD6244. The miRNA screen led to identification of a druggable protein, ITGB1, whose functional inhibition synergizes with MEK inhibitor.

Topics: 3' Untranslated Regions; Benzimidazoles; Breast Neoplasms; Cell Movement; Cell Proliferation; Claudins; Enzyme Inhibitors; Epigenesis, Genetic; Female; Gene Expression Regulation, Neoplastic; Genes, myc; Humans; Integrin beta1; MAP Kinase Kinase Kinases; MicroRNAs; Pyridones; Pyrimidinones

Perturbations in the adipocytokine profile, especially higher levels of leptin, are a major cause of breast tumor progression and metastasis; the underlying mechanisms, however, are not well understood. In particular, it remains elusive whether leptin is involved in epithelial-mesenchymal transition (EMT). Here, we provide molecular evidence that leptin induces breast cancer cells to undergo a transition from epithelial to spindle-like mesenchymal morphology. Investigating the downstream mediator(s) that may direct leptin-induced EMT, we found functional interactions between leptin, metastasis-associated protein 1 (MTA1), and Wnt1 signaling components. Leptin increases accumulation and nuclear translocation of β-catenin leading to increased promoter recruitment. Silencing of β-catenin or treatment with the small molecule inhibitor, ICG-001, inhibits leptin-induced EMT, invasion, and tumorsphere formation. Mechanistically, leptin stimulates phosphorylation of glycogen synthase kinase 3β (GSK3β) via Akt activation resulting in a substantial decrease in the formation of the GSK3β-LKB1-Axin complex that leads to increased accumulation of β-catenin. Leptin treatment also increases Wnt1 expression that contributes to GSK3β phosphorylation. Inhibition of Wnt1 abrogates leptin-stimulated GSK3β phosphorylation. We also discovered that leptin increases the expression of an important modifier of Wnt1 signaling, MTA1, which is integral to leptin-mediated regulation of the Wnt/β-catenin pathway as silencing of MTA1 inhibits leptin-induced Wnt1 expression, GSK3β phosphorylation, and β-catenin activation. Furthermore, analysis of leptin-treated breast tumors shows increased expression of Wnt1, pGSK3β, and vimentin along with higher nuclear accumulation of β-catenin and reduced E-cadherin expression providing in vivo evidence for a previously unrecognized cross-talk between leptin and MTA1/Wnt signaling in epithelial-mesenchymal transition of breast cancer cells.

Topics: beta Catenin; Breast Neoplasms; Bridged Bicyclo Compounds, Heterocyclic; Cadherins; Cell Line, Tumor; Cell Nucleus; Epithelial-Mesenchymal Transition; Female; Gene Expression Regulation, Neoplastic; Glycogen Synthase Kinase 3; Glycogen Synthase Kinase 3 beta; Histone Deacetylases; Humans; Leptin; Phosphorylation; Proto-Oncogene Proteins c-akt; Pyrimidinones; Repressor Proteins; Trans-Activators; Vimentin; Wnt Signaling Pathway; Wnt1 Protein

A series of PI3K-beta selective inhibitors, imidazo[1,2-a]-pyrimidin-5(1H)-ones, has been rationally designed based on the docking model of the more potent R enantiomer of TGX-221, identified by a chiral separation, in a PI3K-beta homology model. Synthesis and SAR of this novel chemotype are described. Several compounds in the series demonstrated potent growth inhibition in a PTEN-deficient breast cancer cell line MDA-MB-468 under anchorage independent conditions.

Topics: Antineoplastic Agents; Binding Sites; Breast Neoplasms; Cell Line, Tumor; Drug Screening Assays, Antitumor; Female; Gene Deletion; Humans; Imidazoles; Isoenzymes; Kinetics; Models, Molecular; Phosphatidylinositol 3-Kinase; Phosphoinositide-3 Kinase Inhibitors; Protein Binding; Protein Kinase Inhibitors; PTEN Phosphohydrolase; Pyrimidinones; Structure-Activity Relationship

Recent evidence suggests that human breast cancer is sustained by a minor subpopulation of breast tumor-initiating cells (BTIC), which confer resistance to anticancer therapies and consequently must be eradicated to achieve durable breast cancer cure.. To identify signaling pathways that might be targeted to eliminate BTIC, while sparing their normal stem and progenitor cell counterparts, we performed global gene expression profiling of BTIC- and mammary epithelial stem/progenitor cell- enriched cultures derived from mouse mammary tumors and mammary glands, respectively. Such analyses suggested a role for the Wnt/Beta-catenin signaling pathway in maintaining the viability and or sustaining the self-renewal of BTICs in vitro. To determine whether the Wnt/Beta-catenin pathway played a role in BTIC processes we employed a chemical genomics approach. We found that pharmacological inhibitors of Wnt/β-catenin signaling inhibited sphere- and colony-formation by primary breast tumor cells and primary mammary epithelial cells, as well as by tumorsphere- and mammosphere-derived cells. Serial assays of self-renewal in vitro revealed that the Wnt/Beta-catenin signaling inhibitor PKF118-310 irreversibly affected BTIC, whereas it functioned reversibly to suspend the self-renewal of mammary epithelial stem/progenitor cells. Incubation of primary tumor cells in vitro with PKF118-310 eliminated their capacity to subsequently seed tumor growth after transplant into syngeneic mice. Administration of PKF118-310 to tumor-bearing mice halted tumor growth in vivo. Moreover, viable tumor cells harvested from PKF118-310 treated mice were unable to seed the growth of secondary tumors after transplant.. These studies demonstrate that inhibitors of Wnt/β-catenin signaling eradicated BTIC in vitro and in vivo and provide a compelling rationale for developing such antagonists for breast cancer therapy.

Topics: Animals; beta Catenin; Breast Neoplasms; Cell Proliferation; Cells, Cultured; Disease Models, Animal; Epithelial Cells; Female; Gene Expression Profiling; Mammary Glands, Animal; Mice; Neoplastic Stem Cells; Pyrimidinones; Receptor, ErbB-2; Triazines; Wnt Proteins; Wnt Signaling Pathway

Inhibition of the protein kinase WEE1 synergizes with chemotherapy in preclinical models and WEE1 inhibitors are being explored as potential cancer therapies. Here, we investigate the mechanism that underlies this synergy. We show that WEE1 inhibition forces S-phase-arrested cells directly into mitosis without completing DNA synthesis, resulting in highly abnormal mitoses characterized by dispersed chromosomes and disorganized bipolar spindles, ultimately resulting in mitotic exit with gross micronuclei formation and apoptosis. This mechanism of cell death is shared by CHK1 inhibitors, and combined WEE1 and CHK1 inhibition forces mitotic entry from S-phase in the absence of chemotherapy. We show that p53/p21 inactivation combined with high expression of mitotic cyclins and EZH2 predispose to mitotic entry during S-phase with cells reliant on WEE1 to prevent premature cyclin-dependent kinase (CDK)1 activation. These features are characteristic of aggressive breast, and other, cancers for which WEE1 inhibitor combinations represent a promising targeted therapy.

Topics: Animals; Antineoplastic Agents; Apoptosis; Breast Neoplasms; Cell Cycle Proteins; Cell Line; Cell Line, Tumor; Checkpoint Kinase 1; Cyclins; Deoxycytidine; DNA-Binding Proteins; Enhancer of Zeste Homolog 2 Protein; Female; Gemcitabine; Gene Expression Regulation, Neoplastic; Humans; Mice; Mice, SCID; Mitosis; Nuclear Proteins; Polycomb Repressive Complex 2; Protein Kinase Inhibitors; Protein Kinases; Protein-Tyrosine Kinases; Pyrazoles; Pyrimidines; Pyrimidinones; Quinolines; S Phase; Thiazoles; Thiophenes; Transcription Factors; Tumor Burden; Tumor Suppressor Protein p53; Urea; Xenograft Model Antitumor Assays

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

Radiotherapy is commonly used to treat a variety of solid tumors. However, improvements in the therapeutic ratio for several disease sites are sorely needed, leading us to assess molecularly targeted therapeutics as radiosensitizers. The aim of this study was to assess the wee1 kinase inhibitor, MK-1775, for its ability to radiosensitize human tumor cells.. Human tumor cells derived from lung, breast, and prostate cancers were tested for radiosensitization by MK-1775 using clonogenic survival assays. Both p53 wild-type and p53-defective lines were included. The ability of MK-1775 to abrogate the radiation-induced G₂ block, thereby allowing cells harboring DNA lesions to prematurely progress into mitosis, was determined using flow cytometry and detection of γ-H2AX foci. The in vivo efficacy of the combination of MK-1775 and radiation was assessed by tumor growth delay experiments using a human lung cancer cell line growing as a xenograft tumor in nude mice.. Clonogenic survival analyses indicated that nanomolar concentrations of MK-1775 radiosensitized p53-defective human lung, breast, and prostate cancer cells but not similar lines with wild-type p53. Consistent with its ability to radiosensitize, MK-1775 abrogated the radiation-induced G₂ block in p53-defective cells but not in p53 wild-type lines. MK-1775 also significantly enhanced the antitumor efficacy of radiation in vivo as shown in tumor growth delay studies, again for p53-defective tumors.. These results indicate that p53-defective human tumor cells are significantly radiosensitized by the potent and selective wee1 kinase inhibitor, MK-1775, in both the in vitro and in vivo settings. Taken together, our findings strongly support the clinical evaluation of MK-1775 in combination with radiation.

Topics: Animals; Antineoplastic Agents; Breast Neoplasms; Cell Cycle Proteins; Cell Line, Tumor; Combined Modality Therapy; Female; G2 Phase Cell Cycle Checkpoints; Humans; Lung Neoplasms; Male; Mice; Mice, Nude; Neoplasms; Nuclear Proteins; Prostatic Neoplasms; Protein Kinase Inhibitors; Protein-Tyrosine Kinases; Pyrazoles; Pyrimidines; Pyrimidinones; Radiation-Sensitizing Agents; Transplantation, Heterologous; Tumor Suppressor Protein p53; Xenograft Model Antitumor Assays

The chaperone Hsp90 is required for the correct folding and maturation of certain "client proteins" within all cells. Hsp90-mediated folding is particularly important in cancer cells, because upregulated or mutant oncogenic proteins are often Hsp90 clients. Hsp90 inhibitors thus represent a route to anticancer agents that have the potential to be active against several different types of cancer. Currently, various Hsp90 inhibitors that bind to Hsp90 at its ATP-binding site are in preclinical and clinical trials. Some of the most promising Hsp90 ATP-binding site inhibitors are the well characterized geldanamycin derivative 17-AAG and the recently described compounds PU-H71 and NVP-AUY922. An undesirable characteristic of these compounds is the transcriptional upregulation of Hsp70 that has prosurvival effects. Here we characterize the activity of a new type of chaperone inhibitor, 1,6-dimethyl-3-propylpyrimido[5,4-e][1,2,4]triazine-5,7-dione (named C9 for simplicity). Using purified protein components in vitro, C9 prevents Hsp90 from interacting with the cochaperone HOP and is thus expected to impair the Hsp90-dependent folding pathway in vivo. We show that this compound is effective in killing various breast cancer cell lines including the highly metastatic MDA-MB-231. An important property of this compound is that it does not induce the transcriptional upregulation of Hsp70. Moreover, when cells are treated with a combination of C9 and either 17-AAG or NVP-AUY922, the overexpression of Hsp70 is counteracted considerably and C9's lethal-IC50 decreases compared to its value when added alone.

Topics: Antineoplastic Agents; Apoptosis; Blotting, Western; Breast Neoplasms; Cell Line, Tumor; Cell Survival; Female; Fibroblasts; Homeodomain Proteins; HSP90 Heat-Shock Proteins; Humans; Inhibitory Concentration 50; Molecular Structure; Pyrimidinones; Triazines; Tumor Suppressor Proteins

Phosphatidylinositol-3-kinase beta (PI3Kβ) is an important therapeutic target in arterial thrombosis and special types of cancer. In this study, a new series of aminopyridine-based PI3Kβ selective inhibitors have been developed by the structure-based design strategy. When incorporated with the phenyl ring on sulfonamide moiety, aminopyrimidine analogs showed good potency on PI3Kβ and selectivity over PI3Kα. Intriguingly, replacement of phenyl group on sulfonamide with naphthyl group enhanced selectivity over PI3Kα while retaining submicromolar PI3Kβ potency. Molecular modeling suggests that increased PI3Kβ specificity is caused by the interaction with salt bridge (Lys782-Asp923) and Asp862 that creat a unique pocket in PI3Kβ. These results clearly provide useful insight in the design of new PI3Kβ inhibitors with high potency and selectivity.

Topics: Aminopyridines; Binding Sites; Breast Neoplasms; Cell Line, Tumor; Drug Discovery; Enzyme Activation; Enzyme Inhibitors; Female; Humans; Hydrogen Bonding; Inhibitory Concentration 50; Models, Molecular; Molecular Structure; Morpholines; Phosphatidylinositol 3-Kinase; Phosphoinositide-3 Kinase Inhibitors; Protein Isoforms; Pyrimidinones; Substrate Specificity

The calcium-permeable cation channel TRPM8 (melastatin-related transient receptor potential member 8) is over-expressed in several cancers. The present study aimed at investigating the expression, function and potential regulation of TRPM8 channels by ER alpha (estrogen receptor alpha) in breast cancer.. RT-PCR, Western blot, immuno-histochemical, and siRNA techniques were used to investigate TRPM8 expression, its regulation by estrogen receptors, and its expression in breast tissue. To investigate the channel activity in MCF-7 cells, we used the whole cell patch clamp and the calcium imaging techniques.. TRPM8 channels are expressed at both mRNA and protein levels in the breast cancer cell line MCF-7. Bath application of the potent TRPM8 agonist Icilin (20 microM) induced a strong outwardly rectifying current at depolarizing potentials, which is associated with an elevation of cytosolic calcium concentration, consistent with established TRPM8 channel properties. RT-PCR experiments revealed a decrease in TRPM8 mRNA expression following steroid deprivation for 48 and 72 hours. In steroid deprived medium, addition of 17-beta-estradiol (E2, 10 nM) increased both TRPM8 mRNA expression and the number of cells which respond to Icilin, but failed to affect the Ca2+ entry amplitude. Moreover, silencing ERalpha mRNA expression with small interfering RNA reduced the expression of TRPM8. Immuno-histochemical examination of the expression of TRPM8 channels in human breast tissues revealed an over-expression of TRPM8 in breast adenocarcinomas, which is correlated with estrogen receptor positive (ER+) status of the tumours.. Taken together, these results show that TRPM8 channels are expressed and functional in breast cancer and that their expression is regulated by ER alpha.

Topics: Adenocarcinoma; Blotting, Western; Breast Neoplasms; Calcium; Cell Line, Tumor; Estradiol; Estrogen Receptor alpha; Female; Gene Expression Regulation, Neoplastic; Humans; Immunohistochemistry; Membrane Potentials; Patch-Clamp Techniques; Pyrimidinones; Reverse Transcriptase Polymerase Chain Reaction; RNA Interference; RNA, Messenger; Time Factors; TRPM Cation Channels

Many breast tumors are hormone-dependent, and estrogens, especially estradiol (E2), have a pivotal role in their growth and development. 17beta-Hydroxysteroid dehydrogenase type 1 (17beta-HSD1) is a key enzyme in the biosynthesis of female sex steroids, catalyzing the NADPH-dependent reduction of estrone into biologically active estradiol. In this study, a library of fused (di)cycloalkeno thieno[2,3-d]pyrimidin-4(3H)-one based compounds was synthesized, and the biological activities against 17beta-HSD1 in a cell-free and in a cell-based assay were evaluated. Several thieno[2,3-d]pyrimidin-4(3H)-one based compounds, at 0.1 and 1 muM test concentrations, were found to be potent 17beta-HSD1 inhibitors. For example, 4-(3-hydroxyphenylthio)-1,2,7,8,9,10,11,13-octahydro-13-oxo-[1]benzothieno[2',3':4,5]-pyrimido[1,2-a]azepine-3-carboxaldehyde (7f) is one of the most potent nonsteroidal 17beta-HSD1 inhibitors reported to date with 94% inhibition of the recombinant enzyme at 0.1 muM test concentration. Importantly, the majority of these compounds exhibited excellent selectivity over the oxidative isoform 17beta-HSD2 and lacked estrogenic effects in an estrogen receptor (ER) binding assay.

Topics: 17-Hydroxysteroid Dehydrogenases; Antineoplastic Agents; Azepines; Breast Neoplasms; Cell Line, Tumor; Estradiol Dehydrogenases; Estrogen Receptor alpha; Estrogen Receptor beta; Estrogens; Female; Humans; Isoenzymes; Models, Molecular; Neoplasms, Hormone-Dependent; Pyrimidinones; Recombinant Proteins; Structure-Activity Relationship; Thiophenes

The Hsp70 molecular chaperones are ATPases that play critical roles in the pathogenesis of many human diseases, including breast cancer. Hsp70 ATP hydrolysis is relatively weak but is stimulated by J domain-containing proteins. We identified pyrimidinone-peptoid hybrid molecules that inhibit cell proliferation with greater potency than previously described Hsp70 modulators. In many cases, anti-proliferative activity correlated with inhibition of J domain stimulation of Hsp70.

Topics: Adenosine Triphosphatases; Breast Neoplasms; Cell Proliferation; Female; HSP70 Heat-Shock Proteins; Humans; Molecular Chaperones; Peptoids; Pyrimidinones

The role of organoselenium compounds as potent cancer chemopreventive and chemotherapeutic agents has been supported by epidemiological, preclinical and clinical studies. In this study, a novel selenadiazole derivative, 1,2,5-selenadiazolo-[3,4-d]pyrimidine-5,7-(4H,6H)-dione (SPO), is identified as a potent antiproliferative agent against human breast adrenocarcinoma MCF-7 cells, human hepatoma HepG2 cells and human melanoma A375 cells. Induction of apoptosis in MCF-7 and A375 cells by SPO was evidenced by accumulation of sub-G1 cell population, DNA fragmentation and nuclear condensation. Further investigation on intracellular mechanisms found that SPO treatments induced activation of caspase-8 and caspase-9, overproduction of reactive oxygen species, and depletion of mitochondrial membrane potential (Delta Psi m) through regulating the expression of pro-survival and pro-apoptotic Bcl-2 family members. Our findings suggest that SPO is a promising novel organoselenium compound with potential in the treatment of human cancers.

Topics: Antineoplastic Agents; Apoptosis; Breast Neoplasms; Caspase 8; Caspase 9; Cell Line, Tumor; DNA Fragmentation; Female; G1 Phase; Gene Expression Regulation; Humans; Liver Neoplasms; Melanoma; Mitochondria; Proto-Oncogene Proteins c-bcl-2; Pyrimidinones; Reactive Oxygen Species

The 17beta-hydroxysteroid dehydrogenase type 1 (17beta-HSD1) enzyme plays a crucial role in female hormonal regulation by catalysing the NADPH-dependent reduction of the less potent estrone E1 into the biologically active estradiol E2. Because 17beta-HSD1 is a key enzyme in E2 biosynthesis, it has emerged as an attractive drug target for inhibitor development. Herein we report the plausible binding modes and a 3D QSAR model of 17beta-HSD1 inhibitors based on a (di)cycloalkenothieno[2,3-d]pyrimidin-4(3H)-one core. Two generated enzyme complexes with potent inhibitors were subjected to molecular dynamics simulation to mimic the dynamic process of inhibitor binding. A set of 17beta-HSD1 inhibitors based on the thieno[2,3-d]pyrimidin-4(3H)-one core were docked into the resulting active site, and a CoMFA model employing the most extensive training set to date was generated. The model was validated with an external test set. Active site residues involved in inhibitor binding and CoMFA fields for steric and electrostatic interactions were identified. The model will be used to guide structural modifications of 17beta-HSD1 inhibitors based on a thieno[2,3-d]pyrimidin-4(3H)-one core in order to improve the biological activity as well as in the design of novel 17beta-HSD1 inhibitors.

Topics: 17-Hydroxysteroid Dehydrogenases; Algorithms; Binding Sites; Breast Neoplasms; Catalysis; Computer Simulation; Enzyme Inhibitors; Female; Humans; Ligands; Molecular Conformation; NADP; Pyrimidinones; Quantitative Structure-Activity Relationship; Thiophenes

A pulsed (17 nanoseconds) Nd:YAG laser (1064 nm) was used to inject impermeable dyes (propidium iodide andiodide and merocyanine 540) and a plasmid (pEGFP-N1) encoding green fluorescent protein (GFP) into human breast adenocarcinoma cells (MCF-7). The cell membrane integrity and viability were fully preserved in this laser-assisted transfer.

Topics: Adenocarcinoma; Breast Neoplasms; Cell Membrane Permeability; Cell Survival; Drug Delivery Systems; Green Fluorescent Proteins; Humans; Lasers; Luminescent Proteins; Microinjections; Plasmids; Propidium; Pyrimidinones; Transfection; Transformation, Genetic; Tumor Cells, Cultured

High-dose chemotherapy combined with autologous stem cell support has improved response rates in high-risk and metastatic breast cancer, but has failed to improve long-term survival. Breast cancer has a tendency to metastasize to the bone marrow, and live tumor cells are known to circulate in the peripheral blood of breast cancer patients. Sensitive immunohistochemical, culture-based, and reverse transcriptase polymerase chain reaction (RT-PCR)-based methods have shown that about 50% of histologically normal stem cell grafts from breast cancer patients are contaminated with occult tumor cells, which may cause or contribute to tumor recurrences. Merocyanine 540 (MC540)-mediated photodynamic therapy (PDT) inactivates a wide range of leukemia and lymphoma cells and is well tolerated by normal hematopoietic stem and progenitor cells. Unfortunately, most solid tumor cells (including breast cancer cells) are only moderately sensitive or refractory to MC540-PDT. We report here that if MC540-PDT is followed by a 1-h incubation with the alkyl-lysophospholipid, Edelfosine (ET-18-OCH(3)), the depletion of murine and human breast cancer cells is greatly enhanced whereas the recovery of normal hematopoietic stem and progenitor cells is only minimally degraded. When used under conditions that reduce CD34-positive human bone marrow cells only 5.1-fold, and murine and human granulocyte/macrophage progenitors 6.8- and 3-fold, respectively, combination purging with MC540-PDT and Edelfosine depletes murine (Mm5MT) and human (MDA-MB-435S) breast cancer cells >17,000- and >125,000-fold, respectively. These data suggest that combination purging with MC540-PDT and Edelfosine may offer a simple, safe and effective method for the ex vivo purging of autologous stem cell grafts from breast cancer patients.

Topics: Animals; Antigens, CD; Antigens, CD34; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Breast Neoplasms; Cryopreservation; Female; Hematopoietic Stem Cells; Humans; Mice; Phospholipid Ethers; Photochemotherapy; Pyrimidinones; Radiation-Sensitizing Agents; Tumor Cells, Cultured; Tumor Stem Cell Assay

In previous studies we have reported that preactivated merocyanine 540 (pMC540) and its chemically synthesized isolates merocil and merodantoin mediate their preferential cytotoxicity towards certain types of malignant cells including human breast cancer cells in vitro and in vivo. The mechanism of cytotoxic action appears to be, in part, via initial interaction with topoisomerase II leading to apoptosis. To further build upon these findings we now show that pMC540 and merodantoin disrupt mitochondrial morphology and function in intact MCF-7 human breast cancer cells as seen by their causing the release of rhodamine 123 from prestained cells, a rapid reduction in ATP levels, inhibition of succinate dehydrogenase activity and oxygen consumption. These data suggest that mitochondria may also be an important target for the cytotoxic action of pMC540 and merodantoin mediated through disruption of the energy balance.

Topics: Adenosine Triphosphate; Antineoplastic Agents; Breast Neoplasms; Cell Survival; Ethylenethiourea; Fluorescent Dyes; Humans; Microscopy, Electron; Microscopy, Fluorescence; Mitochondria; Oxygen Consumption; Pyrimidinones; Rhodamine 123; Rhodamines; Succinate Dehydrogenase; Tumor Cells, Cultured

Preactivation is a novel photochemical method for the production of chemotherapeutic compounds that exert their biologic effects independent of light. The compounds that are produced, preactivated merocyanine 540 (pMC540) and merodantoin, are cytotoxic to cultured human breast cancer cells but are only minimally cytotoxic toward normal cells. Their effects against breast cancer have not been studied in vivo.. Estrogen-stimulated human MCF-7 breast adenocarcinoma cells were grown as solid tumors in athymic carrier mice. Animals bearing defined sizes of subcutaneously transplanted solid breast tumors received injections of pMC540 (250 mg/kg) with or without concurrent treatment with tamoxifen. Growth inhibitory effects of merodantoin (N,N'-dibutyl-2-thio-4,5-imidazolidion) on the breast tumor growth were determined.. Direct injection of established tumors with eight doses of pMC540 (250 mg/kg) administered on alternate days resulted in significant tumor regression (P = 0.002). In three of seven animals, palpable tumors could not be detected after this treatment (16 days). Treatment through intramuscular injections (20 doses) with pMC540 (250 mg/kg) also caused a significant suppression of tumor area (P = 0.004; P = 0.0882; P = 0.0903) and a marginally significant suppression of tumor weight and volume, respectively. Combined treatment with tamoxifen and pMC540 (100 mg/kg) caused a 67% suppression of breast tumor growth. Treatment with 20 doses of merodantoin (75 mg/kg) suppressed the growth of breast tumors by 98%.. To the authors' knowledge, these results show for the first time that photochemically generated novel compounds in pMC540 alone and in combination with tamoxifen are effective in suppressing in vivo growth of xenografted human MCF-7 breast tumors.

Topics: Animals; Breast Neoplasms; Cell Division; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Ethylenethiourea; Humans; Mice; Mice, Inbred BALB C; Mice, Nude; Neoplasms, Hormone-Dependent; Pyrimidinones; Tamoxifen; Transplantation, Heterologous

Topics: Bone Marrow; Bone Marrow Transplantation; Breast Neoplasms; Cell Survival; Colony-Forming Units Assay; Combined Modality Therapy; Doxorubicin; Female; Humans; Laser Therapy; Photochemotherapy; Pyrimidinones; Radiation-Sensitizing Agents; Transplantation, Autologous; Tumor Cells, Cultured

5-fluoro-3,4-dihydro-2,4-dioxo-N-[2-2- (dimethylphenylsilyl)ethylthioethyl]-1(2H)-pyrimidinocarb oxamide (SDK-12B-5), a novel antitumor agent, is covalently linked with 5-fluorouracil (5-FU) and 2-[(2-dimethylphenylsilyl)ethylthio] ethylamine(SDK-103) which possesses itself antitumor activity against murine solid tumors. It has a broad antitumor spectrum in experimental tumor systems including murine leukemias. Furthermore, SDK-12B-5 administered p.o. with various treatment schedules inhibited significantly the tumor growth of human breast cancer (MX-1), colon cancer (Co-4) and lung cancer (LX-1 and OAT) cells in BALB/c nu/nu mice and the chemotherapeutic index was about 10 for 4 different human cancer xenografts. In the Lewis lung carcinoma (LLC) metastasis model, SDK-12B-5 in combination with amputation of tumors inhibited significantly both the lymph node metastases and lung metastases of LLC and prolonged the life span (%ILS:91%) of BDF1 mice. We also found that the cell killing effect of SDK-12B-5 was affected by both concentration and exposure time in cultured human lung cancer (OAT) cells using soft-agar colony assay. A significant augmentation of delayed type hypersensitivity (DTH) response induced by SDK-12B-5 in comparison with the mixture of SDK-103 and 5-FU was seen when it was administered p.o. simultaneously with the immunization of sheep red blood cell (SRBC) in retired CD1 mice. From the studies on tissue distribution and pharmaco-kinetics of SDK-12B-5 by HPLC and ICP analysis. the persistence of SDK-12B-5 levels in serum and tumors was correlated with the findings that a maximum chemotherapeutic effect was obtained when SDK-12B-5 was administered p.o. repeatedly with every other day to avoid the cumulative toxicity.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Breast Neoplasms; Colonic Neoplasms; Ethylamines; Female; Fluorouracil; Humans; Lung Neoplasms; Mammary Neoplasms, Experimental; Mice; Mice, Inbred Strains; Mice, Nude; Neoplasm Transplantation; Neoplasms, Experimental; Organosilicon Compounds; Pyrimidinones; Sarcoma, Experimental; Transplantation, Heterologous