dehydroxymethylepoxyquinomicin and Breast-Neoplasms

There have been great advances in the therapy of cancer and leukemia. However, there are still many neoplastic diseases that are difficult to treat. For example, it is often difficult to find effective therapies for aggressive cancer and leukemia. An NF-κB inhibitor named dehydroxymethylepoxyquinomicin (DHMEQ) was discovered in 2000. This compound was designed based on the structure of epoxyquinomicin isolated from a microorganism. It was shown to be a specific inhibitor that directly binds to and inactivates NF-κB components. Until now, DHMEQ has been used by many scientists in the world to suppress animal models of cancer and inflammation. Especially, it was shown to suppress difficult cancer models, such as hormone-insensitive breast cancer and prostate cancer, cholangiocarcinoma, and multiple myeloma. No toxicity has been reported so far. DHMEQ was administered via the intraperitoneal (IP) route in most of the animal experiments because of its simplicity. In the course of developmental studies, it was found that IP administration never increased the blood concentration of DHMEQ because of the instability of DHMEQ in the blood. It is suggested that inflammatory cells in the peritoneal cavity would be important for cancer progression, and that IP administration, itself, is important for the effectiveness and safety of DHMEQ. In the present review, we describe mechanism of action, its in vivo anticancer activity, and future clinical use of DHMEQ IP therapy.

Topics: Animals; Antineoplastic Agents; Benzamides; Breast Neoplasms; Cyclohexanones; Female; Humans; Injections, Intraperitoneal; Lymphoma; Male; Mice; Multiple Myeloma; Neoplasms; NF-kappa B

The three-dimensional (3D) culture of cancer cells provides an environmental condition closely related to the condition in vivo. It would especially be an ideal model for the early phase of metastasis, including the detachment and invasion of cancer cells from the primary tumor. In one hand, dehydroxymethylepoxyquinomicin (DHMEQ), an NF-κB inhibitor, is known to inhibit cancer progression and late phase metastasis in animal experiments. In the present research, we studied the inhibitory activity on the 3D invasion of breast carcinoma cells. Breast carcinoma MDA-MB-231 cells showed the most active invasion from spheroid among the cell lines tested. DHMEQ inhibited the 3D invasion of cells at the 3D-nontoxic concentrations. The PCR array analysis using RNA isolated from the 3D on-top cultured cells indicated that matrix metalloproteinase (MMP)-2 expression is lowered by DHMEQ. Knockdown of MMP-2 and an MMP inhibitor, GM6001, both inhibited the invasion. DHMEQ was shown to inhibit the promoter activity of MMP-2 in the reporter assay. Thus, DHMEQ was shown to inhibit NF-κB/MMP-2-dependent cellular invasion in 3D-cultured MDA-MB-231 cells, suggesting that DHMEQ would inhibit the early phase of metastasis.

Topics: Antineoplastic Agents; Benzamides; Breast; Breast Neoplasms; Cell Line, Tumor; Cyclohexanones; Down-Regulation; Female; Gene Expression Regulation, Neoplastic; Humans; Matrix Metalloproteinase 2; Matrix Metalloproteinase Inhibitors; Neoplasm Invasiveness; NF-kappa B; Promoter Regions, Genetic

We previously discovered (-)-DHMEQ as a selective inhibitor of NF-κB, and it was shown to suppress many cancer and inflammation models in animals. (-)-DHMEQ directly binds to NF-κB components to inhibit DNA binding, and moreover, it often inhibits nuclear translocation of NF-κB. The mechanism of inhibiting nuclear translocation has been elucidated for RelB, a main noncanonical NF-κB component. However, it was not elucidated for p65, a main canonical NF-κB component. In the present research, we studied how (-)-DHMEQ inhibits nuclear localization of p65. First, (-)-DHMEQ inhibited p65 nuclear accumulation in adult T-cell leukemia MT-2 cells in which canonical p65 is constitutively activated. But there was no change in the stability and importin-α3 affinity of p65. Then, we prepared a p65 mutant protein with Arg35Ala and Tyr36Ala (AA) mutations having no DNA-binding ability in HeLa cells. The p65 AA mutant showed reduced nuclear localization without changing the stability and importin affinity. Taken together, the mechanism of inhibition is different between RelB and p65, and inhibition of p65 nuclear localization is likely to be due to the inhibition of DNA binding changing the equilibrium between the nuclear and cytoplasmic amounts of p65.

Topics: Benzamides; Breast Neoplasms; Cell Line, Tumor; Cell Nucleus; Cyclohexanones; DNA; Enzyme Activation; Gene Expression; HeLa Cells; Humans; Leukemia-Lymphoma, Adult T-Cell; Models, Biological; Mutation; NF-kappa B; Protein Binding; Protein Transport; Transcription Factor RelA

Galectin-3-binding protein (G3BP) is highly expressed in various types of cancer and is thought to be involved in cancer malignancy; however, the role of G3BP in breast cancer cells is not fully understood. In this study, we investigated the role of NF-κB in the adhesion of breast cancer cells to a substrate by using (-)-DHMEQ, a specific inhibitor of NF-κB. (-)-DHMEQ inhibited both TNF-α-induced G3BP expression and cell adhesion in human breast cancer cell lines. We also found that knockdown of G3BP suppressed the adhesion, while its overexpression increased the adhesion. These data reveal that (-)-DHMEQ suppresses breast cancer cell adhesion by inhibiting NF-κB-regulated G3BP expression.

Topics: Antigens, Neoplasm; Benzamides; Biomarkers, Tumor; Breast Neoplasms; Carrier Proteins; Cell Adhesion; Cell Line, Tumor; Cyclohexanones; Female; Glycoproteins; Humans; NF-kappa B; RNA Interference; RNA, Small Interfering; Tumor Necrosis Factor-alpha

Coffee is a beverage that is consumed world-wide on a daily basis and is known to induce a series of metabolic and pharmacological effects, especially in the digestive tract. However, little is known concerning the effects of coffee on transporters in the gastrointestinal tract. To elucidate the effect of coffee on intestinal transporters, we investigated its effect on expression of the breast cancer resistance protein (BCRP/ABCG2) in a human colorectal cancer cell line, Caco-2. Coffee induced BCRP gene expression in Caco-2 cells in a coffee-dose dependent manner. Coffee treatment of Caco-2 cells also increased the level of BCRP protein, which corresponded to induction of gene expression, and also increased cellular efflux activity, as judged by Hoechst33342 accumulation. None of the major constituents of coffee tested could induce BCRP gene expression. The constituent of coffee that mediated this induction was extractable with ethyl acetate and was produced during the roasting process. Dehydromethylepoxyquinomicin (DHMEQ), an inhibitor of nuclear factor (NF)-κB, inhibited coffee-mediated induction of BCRP gene expression, suggesting involvement of NF-κB in this induction. Our data suggest that daily consumption of coffee might induce BCRP expression in the gastrointestinal tract and may affect the bioavailability of BCRP substrates.

Topics: ATP Binding Cassette Transporter, Subfamily G, Member 2; ATP-Binding Cassette Transporters; Benzamides; Benzimidazoles; Breast Neoplasms; Caco-2 Cells; Cell Culture Techniques; Coffee; Cyclohexanones; Dose-Response Relationship, Drug; Drug Evaluation, Preclinical; Female; Gene Expression; Humans; Molecular Targeted Therapy; Neoplasm Proteins; NF-kappa B; Plant Extracts

Tumour-initiating cells (TICs) or cancer stem cells can exist as a small population in malignant tissues. The signalling pathways activated in TICs that contribute to tumourigenesis are not fully understood.. Several breast cancer cell lines were sorted with CD24 and CD44, known markers for enrichment of breast cancer TICs. Tumourigenesis was analysed using sorted cells and total RNA was subjected to gene expression profiling and gene set enrichment analysis (GSEA).. We showed that several breast cancer cell lines have a small population of CD24(-/low)/CD44(+) cells in which TICs may be enriched, and confirmed the properties of TICs in a xenograft model. GSEA revealed that CD24(-/low)/CD44(+) cell populations are enriched for genes involved in transforming growth factor-beta, tumour necrosis factor, and interferon response pathways. Moreover, we found the presence of nuclear factor-kappaB (NF-kappaB) activity in CD24(-/low)/CD44(+) cells, which was previously unrecognised. In addition, NF-kappaB inhibitor dehydroxymethylepoxyquinomicin (DHMEQ) prevented tumourigenesis of CD24(-/low)/CD44(+) cells in vivo.. Our findings suggest that signalling pathways identified using GSEA help to identify molecular targets and biomarkers for TIC-like cells.

Topics: Animals; Benzamides; Biomarkers; Breast Neoplasms; CD24 Antigen; Cell Separation; Cyclohexanones; Female; Gene Expression Profiling; Genetic Vectors; Humans; Hyaluronan Receptors; Mice; Mice, Inbred NOD; Mice, SCID; Neoplasm Proteins; Neoplastic Stem Cells; NF-kappa B; Oligonucleotide Array Sequence Analysis; Signal Transduction; Transduction, Genetic; Xenograft Model Antitumor Assays

We previously designed and synthesized the new nuclear factor kappaB (NF-kappaB) inhibitor dehydroxymethylepoxyquinomicin (DHMEQ) derived from the structure of the antibiotic epoxyquinomicin C. We looked into the effect of DHMEQ on cellular phenotypes and tumor growth in mice injected with human breast carcinoma cell line MDA-MB-231 or MCF-7. In estrogen-independent breast adenocarcinoma cell line MDA-MB-231, NF-kappaB is constitutively activated. The addition of DHMEQ (10 microg/mL) completely inhibited the activated NF-kappaB for at least 8 hours. On the other hand, NF-kappaB is not activated in estrogen-dependent MCF-7 cells. In this cell line, DHMEQ completely inhibited the tumor necrosis factor-alpha-induced activation of NF-kappaB. DHMEQ did not inhibit the degradation of IkappaB but inhibited the nuclear translocation of NF-kappaB by both p65/p50 and RelB/p52 pathways. MDA-MB-231 cells secrete interleukin (IL)-6 and IL-8 without stimulation, and DHMEQ decreased the secretion levels of both cytokines. When MDA-MB-231 or MCF-7 cells were stimulated by tumor necrosis factor-alpha, the inhibitory effects of DHMEQ were still maintained. I.p. administration of DHMEQ (thrice a week) significantly inhibited the tumor growth of MDA-MB-231 (12 mg/kg) or MCF-7 (4 mg/kg) in severe combined immunodeficiency mice. No toxicity was observed during the experiment, including the loss of body weight. An immunohistological study on resected MCF-7 tumors showed that DHMEQ inhibited angiogenesis and promoted apoptosis. Furthermore, in Adriamycin-resistant MCF-7 cells highly expressing multidrug resistance gene-1, DHMEQ also exhibited the above capability, including down-regulation of IL-8. Thus, DHMEQ might be a potent drug for the treatment of various breast carcinomas by inhibiting the NF-kappaB activity.

Topics: Angiogenesis Inhibitors; Animals; Antineoplastic Agents; Apoptosis; Benzamides; Breast Neoplasms; Cell Line, Tumor; Cyclohexanones; Dose-Response Relationship, Drug; Doxorubicin; Female; Humans; Interleukin-6; Interleukin-8; Lymphotoxin-alpha; Male; Mice; Mice, Inbred BALB C; Mice, SCID; NF-kappa B; Phosphorylation; Signal Transduction; Time Factors; Tumor Necrosis Factor-alpha; Xenograft Model Antitumor Assays