xct790 and Triple-Negative-Breast-Neoplasms

The estrogen-related receptor α (ERRα) is an orphan receptor and a novel target for solid tumor therapy, conceivably through effects on the regulation of tumor cell energy metabolism associated with energy stress within solid tumor micro environments. Here we describe the discovery of novel potent inverse agonists of ERRα. In vitro, compound 11 potently inhibits ERRα's transcriptional activity by preventing endogenous PGC-1α and ERRα binding and suppresses the proliferation of different human cancer cell lines and the migration of breast cancer cells (MDA-MB-231). In vivo, compound 11 demonstrates a strong inhibitory effect on the growth of human breast cancer xenografts (MDA-MB-231) and the tumor growth is inhibited by 40.9% after treating with compound 11 (30 mg/kg). The binding mode shows that compound 11 interacts with the binding pocket of ERRα through hydrogen interactions with the residue Gly397 and hydrophobic interactions with the hydrophobic residues. All these results suggest that compound 11 represents a novel potent ERRα inverse agonist and is promising in the discovery of antitumor compounds for the treatment of triple negative breast cancer.

Topics: Antineoplastic Agents; Cell Line, Tumor; Cell Proliferation; Dose-Response Relationship, Drug; Drug Discovery; Drug Screening Assays, Antitumor; ERRalpha Estrogen-Related Receptor; Female; Humans; Molecular Structure; Nitriles; Receptors, Estrogen; Structure-Activity Relationship; Thiazoles; Triple Negative Breast Neoplasms

There is an urgent clinical need for targeted therapy approaches for triple-negative breast cancer (TNBC) patients. Increasing evidences suggested that the expression of estrogen-related receptor alpha (ERRα) was correlate with unfavorable clinical outcomes of breast cancer patients. We here show that inhibition of ERRα by its inverse agonist XCT-790 can suppress the proliferation, decrease G2/M phases, and induce mitochondrial-related apoptosis of TNBC cells. XCT-790 elevates the proteins related to endoplasmic reticulum (ER) stress such as ATF4/6, XBT-1 and CHOP. It also increases the expression of growth inhibition related proteins such as p53 and p21. Further, XCT-790 can increase the generation of reactive oxygen species (ROS) in TNBC cells mainly through inhibition of SOD1/2. While ROS scavenger NAC abolishes XCT-790 induced ER-stress and growth arrest. XCT-790 treatment can rapidly activate the signal molecules including ERK1/2, p38-MAPK, JNK, Akt, p65, and IκBα, while NAC attenuates effects of XCT-790 induced phosphorylation of ERK1/2, p38-MAPK and Akt. Further, the inhibitors of ERK1/2, JNK, Akt, and NF-κB attenuate XCT-790 induced ROS generation. These data suggest that AKT/ROS and ERK/ROS positive feedback loops, NF-κB/ROS, and ROS/p38-MAPK, are activated in XCT-790 treated TNBC cells. In vivo experiments show that XCT-790 significantly suppresses the growth of MDA-MB-231 xenograft tumors, which is associated with up regulation of p53, p21, ER-stress related proteins while down regulation of bcl-2. The present discovery makes XCT-790 a promising candidate drug and lays the foundation for future development of ERRα-based therapies for TNBC patients.

Topics: Animals; Antineoplastic Agents; Cell Line, Tumor; Cell Proliferation; ERRalpha Estrogen-Related Receptor; Female; Humans; Mice; Nitriles; Reactive Oxygen Species; Receptors, Estrogen; Signal Transduction; Thiazoles; Triple Negative Breast Neoplasms; Xenograft Model Antitumor Assays

Triple-negative breast cancer (TNBC) patients have poor prognosis due to the aggressive metastatic behaviors. Our study reveals that expression of estrogen related receptor α (ERRα) is significantly (p < 0.01) positively associated with high grade tumors and lymph node metastasis, while negatively correlated with overall survival (OS), in 138 TNBC patients. Targeted inhibition of ERRα by its inverse agonist XCT-790 or si-RNA obviously inhibits in vitro motility of TNBC cells. While over expression of ERRα triggers the invasion and migration of TNBC cells. Further, si-ERRα and XCT-790 inhibit the epithelial mesenchymal transition (EMT) of TNBC cells with increasing the expression of E-cadherin and decreasing fibronectin (FN) and vimentin. While XCT-790 has no effect on the expression of EMT related transcription factors such as Snail or Slug. Further, inhibitors of MAPK, PI3K/Akt, NF-κB signal molecules, which are activated by XCT-790, can not attenuate the suppression effects of XCT-790 on EMT. Alternatively, luciferase reporter gene assays and ChIP analysis indicate that ERRα can directly bind with FN promoter at ERR response element-3 (ERRE-1), ERRE-3, and ERRE-4, while XCT-790 reduces this bond. In vivo data show that ERRα expression is significantly (p < 0.05) correlated with FN in clinical TNBC patients. In MDA-MB-231 tumor xenograft models, XCT-790 decreases the expression of FN, inhibits the growth and lung metastasis, and suppresses the EMT. Our results demonstrate that ERRα functions as a metastasis stimulator and its targeted inhibition may be a new therapeutic strategy for TNBC treatment.

Topics: Animals; Antineoplastic Agents; Binding Sites; Cell Movement; Dose-Response Relationship, Drug; Drug Inverse Agonism; Epithelial-Mesenchymal Transition; ERRalpha Estrogen-Related Receptor; Female; Fibronectins; Gene Expression Regulation, Neoplastic; Hep G2 Cells; Humans; Lung Neoplasms; MCF-7 Cells; Mice, Nude; Middle Aged; Nitriles; Promoter Regions, Genetic; Protein Binding; Receptors, Estrogen; Retrospective Studies; RNA Interference; Signal Transduction; Thiazoles; Time Factors; Transfection; Triple Negative Breast Neoplasms; Xenograft Model Antitumor Assays