Tumor mitochondrial oxidative phosphorylation stimulated by the nuclear receptor RORγ represents an effective therapeutic opportunity in osteosarcoma
Ontology highlight
ABSTRACT: Osteosarcoma (OS) is the most common malignant bone tumor with a poor prognosis. The treatment strategy has remained virtually unchanged over the past 40 years. Here, we show that the nuclear receptor RORγ may serve as a potential therapeutic target in osteosarcoma. OS exhibits a hyperactivated OXPHOS program, which fuels the carbon source to promote tumor progression. We found that RORγ is overexpressed in OS tumors and is linked to hyperactivated OXPHOS. RORγ induces the expression of PGC-1β and physically interacts with it to activate the OXPHOS program by upregulating the expression of respiratory chain component genes. Knockdown or pharmacological inhibition of RORγ strongly inhibits OXPHOS activation, downregulates mitochondrial functions and increases ROS production, which results in OS cell apoptosis and ferroptosis. RORγ inverse agonists strongly suppressed OS tumor growth and progression in multiple cell-based xenograft models and in chemotherapy-resistant, patient-derived xenograft (PDX) models and sensitized OS tumors to chemotherapy without obvious toxicity in mice. Taken together, our results indicate that RORγ is a critical regulator of the OXPHOS program in OS and provide a potential therapeutic strategy for this deadly disease.
Project description:Peritoneal metastasis (PM) is diagnosed in almost half of patients with advanced gastric cancer (GCa) and has a very poor prognosis. However, the molecular mechanisms of PM in GCa remain poorly understood. Here, we show that the elevated expression of RAR-related orphan receptor gamma (RORγ) in GCa tumors is a key driver of PM. RORγ drives GCa progression and metastasis by assembling a transcriptional complex with HIF-1α that regulates the expression of HIF-1α targets via recruitment of RNA polymerase II and p300. Mechanistically, RORγ hijacks HIF-1α to disrupt the interaction between HIF-1α and PHD3, leading to decreased HIF-1α hydroxylation, ubiquitylation and increased HIF-1α accumulation, nuclear translocation, and transactivation. RORγ antagonists block tumor growth and PM in multiple xenograft GCa models, and they effectively sensitize GCa tumors to chemotherapy in mice. Thus, our study uncovers a mechanism of RORγ-driven PM and offers a potential therapeutic option against advanced GCa.
Project description:Peritoneal metastasis (PM) is diagnosed in almost half of patients with advanced gastric cancer (GCa) and has a very poor prognosis. However, the molecular mechanisms of PM in GCa remain poorly understood. Here, we show that the elevated expression of RAR-related orphan receptor gamma (RORγ) in GCa tumors is a key driver of PM. RORγ drives GCa progression and metastasis by assembling a transcriptional complex with HIF-1α that regulates the expression of HIF-1α targets via recruitment of RNA polymerase II and p300. Mechanistically, RORγ hijacks HIF-1α to disrupt the interaction between HIF-1α and PHD3, leading to decreased HIF-1α hydroxylation, ubiquitylation and increased HIF-1α accumulation, nuclear translocation, and transactivation. RORγ antagonists block tumor growth and PM in multiple xenograft GCa models, and they effectively sensitize GCa tumors to chemotherapy in mice. Thus, our study uncovers a mechanism of RORγ-driven PM and offers a potential therapeutic option against advanced GCa.
Project description:We show that triple-negative breast cancer (TNBC) exhibits a hyper-activated MVA-CB program that is strongly linked to nuclear receptor RORγ, compared to estrogen receptor-positive breast cancer. Genetic and pharmacological inhibition of RORγ reduces tumor cholesterol contents and synthesis rate while preserving host cholesterol homeostasis. We demonstrate, for the first time, that RORγ functions as a master activator of the entire MVA-CB program, dominantly over SREBP2, through its own direct binding and facilitating the recruitment of SREBP2. RORγ inhibition disrupts its association with SREBP2 and reduces MVA-CB chromatin acetylation. RORγ antagonists cause sustained TNBC tumor regression in patient-derived and immune-intact models. Their combination with cholesterol-lowering statins elicits superior anti-tumor synergy selectively in TNBC. Together, our studies uncover a previously unsuspected master regulator of MVA-CB and an attractive target for TNBC.
Project description:We show that triple-negative breast cancer (TNBC) exhibits a hyper-activated MVA-CB program that is strongly linked to nuclear receptor RORγ, compared to estrogen receptor-positive breast cancer. Genetic and pharmacological inhibition of RORγ reduces tumor cholesterol contents and synthesis rate while preserving host cholesterol homeostasis. We demonstrate, for the first time, that RORγ functions as a master activator of the entire MVA-CB program, dominantly over SREBP2, through its own direct binding and facilitating the recruitment of SREBP2. RORγ inhibition disrupts its association with SREBP2 and reduces MVA-CB chromatin acetylation. RORγ antagonists cause sustained TNBC tumor regression in patient-derived and immune-intact models. Their combination with cholesterol-lowering statins elicits superior anti-tumor synergy selectively in TNBC. Together, our studies uncover a previously unsuspected master regulator of MVA-CB and an attractive target for TNBC.
Project description:Approximately 80%-90% of hepatocellular carcinomas (HCC) occur in a premalignant environment of fibrosis and abnormal extracellular matrix (ECM), predicting an essential role of abnormal matrix in the tumorigenesis and progress of HCC. However, the determinants of ECM in HCC are poorly defined. Here, we show that nuclear receptor RORγ is highly expressed and amplified in HCC tumors. RORγ functions as an essential activator of the matrisome program via directly driving the expression of major ECM genes in HCC cells. The elevated RORγ increased Fibronectin-1 deposition, cell-matrix adhesion, collagen production and cross-linkling, creating a favorable microenvironment to boost liver cancer metastasis. Moreover, RORγ antagonists effectively inhibit tumor growth and metastasis via ECM remodeling in multiple HCC xenografts and immune-intact models, and they effectively sensitize HCC tumors to sorafenib therapy in mice. Notably, the elevated RORγ expression is associated with ECM remodeling and metastasis in patients with HCC. Taken together, we identify RORγ as a key player in HCC progression by remodeling ECM and as an attractive therapeutic target for advanced HCC.
Project description:We show that RORγ functions as a master activator of the entire mevalonate pathway-cholesterol biosynthesis program in the porcine liver. RORγ genome-wide binding enrichments in the liver were significantly reduced in response to mycotoxin exposure.
Project description:Osteosarcoma (Osteosarcoma) is a type of bone cancer. Eighty percent of this tumor will be metastatic to the lungs or liver, and as a result, patients generally need chemotherapy to improve survival possibility. Recently, anti-tumor activity has been reported in Ocimum gratissimum aqueous extract (OGE), which has been the focus of recent extensive studies on therapeutic strategies due to its antioxidant properties. We used microarrays to identify potential and novel target genes responsive to the anticancer effect in OGE treatment in osteosarcoma cells, We performed pharmacogenomics analyses for the effect of OGE on human osteosarcoma U2-OS and HOS cell growth. Cell viability, Western blot and flow cytometry analysis were performed before performing pharmacogenomics analyses for the effect of OGE on human osteosarcoma U2-OS and HOS cell growth, including cDNA microarray and RT-PCR assays.
Project description:Although the introduction of combined neoadjuvant chemotherapy has significantly prolonged the survival, the outcome of OS patients with poor response to chemotherapy is still unfavorable. To develop new therapeutics the elucidation of the entire molecular pathway regulating OS cell proliferation is warranted. We analysed the expression levels of 933 miRNA probes in surgical 24 samples and 8 cell lines of osteosarcoma with 3D-Gene human miRNA oligo chips. Total RNA was extracted from 24 fresh frozen tumour specimens and 8 OS cell lines. We analysed the global miRNA exprssion profiles of these osteosarcoma cases in order to find new novel potential targets for the development of therapeutic targeting OS.
Project description:We report here that RORγ, a nuclear receptor family member, unexpectedly mediates MDR1/ABCB1 overexpression. RORγ plays an important role in controlling the functions of subsets of immune cells and has been an attractive target for autoimmune diseases. We found that its small-molecule antagonists are efficacious in re-sensitizing DTX and CTX cross-resistant CRPC cells and tumors to taxanes in both androgen receptor (AR)-positive and -negative models. Our mechanistic analyses revealed that combined treatment with RORγ antagonists and taxane elicited a robust synergy in killing the resistant cells, which involves a coordinated alteration of p53, Myc and E2F-controlled programs critical for both intrinsic and extrinsic apoptosis, survival and cell growth. Our results suggest that targeting RORγ with small-molecule inhibitors is a novel strategy for chemotherapy resensitization in tumors with MDR1 overexpression.
Project description:Cancer stem cells (CSCs) are proposed to be unique subsets of clones within a tumor, attributed with tumor progression, resistance to chemotherapy, and metastases. However, little is known about the molecular mechanisms regulating the acquisition and maintenance of CSC properties in cancers, especially in rare cancers, such as osteosarcoma (OS). In this study, we generated OS cells with CSC properties following transduction of defined factors. This method enabled us to obtain abundant OS CSC material. The results of our study could facilitate a better understanding of the mechanisms of OS progression, and aid in the development of new therapies targeting CSCs in patients with OS.