xct790 and Breast-Neoplasms

Monocarboxylate transporters (MCTs) and lactate dehydrogenase A (LDH-A) play important roles in sustaining the glycolytic phenotype seen in cancer. Endurance training improves aerobic capacity; however, whether endurance training alters the metabolic phenotype of a solid tumour, from the perspective of lactate metabolism, is yet to be proven. This study showed that endurance training decreases expression of the MCT1 basigin (CD147) and LDH-A , and also increases LDH-B expression in solid tumours and attenuates tumour lactate metabolism. Similar results for MCT1 and LDH-B were found with inhibition of the oestrogen-related receptor alpha (ERRα). The training effects were not additive to the ERRα effects on MCT1 and LDH-B expression in the tumour, which indicated that exercise-induced alterations in MCT1 and LDH-B expression were modulated by ERRα. These results suggest that endurance training could be a useful tool in cancer therapy, especially in basal-like and luminal-like breast carcinomas.. Several factors, including overexpression of lactate dehydrogenase (LDH) and monocarboxylate transporters (MCTs), promote an aerobic lactate production that allows some cancer cells to sustain higher proliferation rates in hostile environments outside the cell. To elucidate the effect of endurance training on the metabolic phenotype of solid tumours, we focused on the tumour expression of LDH-A, LDH-B, MCT1, MCT4, oestrogen-related receptor alpha (ERRα) and LDH isozymes in control (C), trained (T), control+XCT790 (CX) and trained+XCT790 (TX) mice. First, we found that the metabolically altered tumours from the trained animals exhibited lower values for lactate concentration than the control group. The decreased lactate concentration was associated with a shift in the tumour LDH isozyme profile towards LDH-1. These exercise-induced changes were also associated with decreases in the expression of the tumour MCT1, ERRα and CD147 in the trained animals. Secondly, the inhibition of ERRα by treatment of MC4-L2 human breast cancer cells with XCT790 (inverse agonist ligand of ERRα) before injection into the animals not only increased LDH-B expression in the tumour, but also decreased MCT1 expression in the CX group in comparison to the C group. The effects of ERRα inhibition were not additive to the training effects on the expressions of MCT1 and LDH-B in the solid tumours. In conclusion, our results suggest that exercise-induced suppression of ERRα expression modulates alterations in solid tumour expression of LDH-B and MCT1 and contributes towards the prevention of tumour development.

Topics: Animals; Basigin; Breast Neoplasms; Cell Line, Tumor; ERRalpha Estrogen-Related Receptor; Female; Humans; Isoenzymes; L-Lactate Dehydrogenase; Lactate Dehydrogenase 5; Lactic Acid; Mice, Inbred BALB C; Monocarboxylic Acid Transporters; Muscle Proteins; Nitriles; Physical Conditioning, Animal; Receptors, Estrogen; Symporters; Thiazoles; Tumor Burden

Here, we show that new mitochondrial biogenesis is required for the anchorage independent survival and propagation of cancer stem-like cells (CSCs). More specifically, we used the drug XCT790 as an investigational tool, as it functions as a specific inhibitor of the ERRα-PGC1 signaling pathway, which governs mitochondrial biogenesis. Interestingly, our results directly demonstrate that XCT790 efficiently blocks both the survival and propagation of tumor initiating stem-like cells (TICs), using the MCF7 cell line as a model system. Mechanistically, we show that XCT790 suppresses the activity of several independent signaling pathways that are normally required for the survival of CSCs, such as Sonic hedgehog, TGFβ-SMAD, STAT3, and Wnt signaling. We also show that XCT790 markedly reduces oxidative mitochondrial metabolism (OXPHOS) and that XCT790-mediated inhibition of CSC propagation can be prevented or reversed by Acetyl-L-Carnitine (ALCAR), a mitochondrial fuel. Consistent with our findings, over-expression of ERRα significantly enhances the efficiency of mammosphere formation, which can be blocked by treatment with mitochondrial inhibitors. Similarly, mammosphere formation augmented by FOXM1, a downstream target of Wnt/β-catenin signaling, can also be blocked by treatment with three different classes of mitochondrial inhibitors (XCT790, oligomycin A, or doxycycline). In this context, our unbiased proteomics analysis reveals that FOXM1 drives the expression of >90 protein targets associated with mitochondrial biogenesis, glycolysis, the EMT and protein synthesis in MCF7 cells, processes which are characteristic of an anabolic CSC phenotype. Finally, doxycycline is an FDA-approved antibiotic, which is very well-tolerated in patients. As such, doxycycline could be re-purposed clinically as a 'safe' mitochondrial inhibitor, to target FOXM1 and mitochondrial biogenesis in CSCs, to prevent tumor recurrence and distant metastasis, thereby avoiding patient relapse.

Topics: Acetylcarnitine; Breast Neoplasms; Cell Adhesion; Cell Proliferation; Cell Survival; Chromatography, Liquid; Doxycycline; ERRalpha Estrogen-Related Receptor; Forkhead Box Protein M1; Forkhead Transcription Factors; Glycolysis; Humans; MCF-7 Cells; Mitochondria; Neoplastic Stem Cells; Nitriles; Oligomycins; Organelle Biogenesis; Oxidative Phosphorylation; Proteomics; Receptors, Estrogen; Signal Transduction; Spheroids, Cellular; Tandem Mass Spectrometry; Thiazoles; Wnt Signaling Pathway

Estrogen-related receptor α is a potential candidate target for therapeutic treatment of breast cancer. We describe the discovery and structure-activity relationship study of a series of 1-phenyl-4-benzoyl-1H-1,2,3-triazoles as novel suppressors of ERRα transcriptional functions. The most promising compound, 2-aminophenyl-(1-(3-isopropylphenyl)-1H-1,2,3-triazol-4-yl)methanone (14n), potently suppressed the transcriptional functions of ERRα with IC50 = 0.021 μM in a cell-based reporter gene assay and also decreased both the mRNA levels and the protein levels of ERRα and the downstream targets. This compound inhibited the proliferation and migration of breast cancer cells with high level of ERRα. Preliminary pharmacokinetic studies suggested that it possessed a good pharmacokinetic profile with an oral bioavailability of 71.8%. The compounds may serve as novel small molecule probes for further validation of ERRα as a molecular target for anticancer drug development.

Topics: Administration, Oral; Aniline Compounds; Animals; Antineoplastic Agents; Biological Availability; Breast Neoplasms; Cell Line; Cell Line, Tumor; Drug Screening Assays, Antitumor; ERRalpha Estrogen-Related Receptor; Female; Genes, Reporter; Humans; Luciferases; Male; Rats; Rats, Sprague-Dawley; Receptors, Estrogen; RNA, Messenger; Structure-Activity Relationship; Transcription, Genetic; Triazoles

A genomic signature designed to assess the activity of the estrogen-related receptor alpha (ERRα) was used to profile more than 800 breast tumors, revealing a shorter disease-free survival in patients with tumors exhibiting elevated receptor activity. Importantly, this signature also predicted the ability of an ERRα antagonist, XCT790, to inhibit proliferation in cellular models of breast cancer. Using a chemical genomic approach, it was determined that activation of the Her2/IGF-1R signaling pathways and subsequent C-MYC stabilization upregulate the expression of peroxisome proliferator-activated receptor gamma coactivator-1 beta (PGC-1β), an obligate cofactor for ERRα activity. PGC-1β knockdown in breast cancer cells impaired ERRα signaling and reduced cell proliferation, implicating a functional role for PGC-1β/ERRα in the pathogenesis of breast cancers.

Topics: Breast Neoplasms; Carrier Proteins; Cell Proliferation; ERRalpha Estrogen-Related Receptor; Female; Humans; Nitriles; Receptor, ErbB-2; Receptor, IGF Type 1; Receptors, Estrogen; RNA-Binding Proteins; Signal Transduction; Thiazoles

ICI182,780 (Fulvestrant) is a pure anti-estrogen used in adjuvant therapies of breast cancer. This compound not only inhibits the transcriptional activities of the estrogen receptor-alpha (ER alpha) but also induces its proteasome-dependent degradation. The latter activity is believed to be required for the antiproliferative effects of ICI182,780. Estrogen receptor-related receptor-alpha (ERR alpha) is an orphan member of the nuclear receptor superfamily that is expressed in a wide range of tissues including breast tumors, in which its high expression correlates with poor prognosis. Although not regulated by any natural ligand, ERR alpha can be deactivated by the synthetic molecule XCT790. Here we demonstrate that this compound also induces a proteasome degradation of ERR alpha. We also show that although it does not act directly on the steady-state level of ER alpha, XCT790 potentiates the ICI182,780-induced ER alpha degradation. We suggest that treatment with XCT790 could thus enhance the efficacy of ICI182,780 in ER alpha-dependent pathologies such as breast cancer.

Topics: Antineoplastic Agents, Hormonal; Breast Neoplasms; Cell Line, Tumor; Drug Synergism; ERRalpha Estrogen-Related Receptor; Estradiol; Estrogen Receptor alpha; Female; Fulvestrant; Gene Expression Regulation, Neoplastic; Humans; Nitriles; Prognosis; Proteasome Endopeptidase Complex; Receptors, Estrogen; Thiazoles