Project description:By utilizing proteomic and transcriptomic analysis coupled with untargeted polar and non-polar metabolite analysis by liquid chromatography/mass spectrometry, we identified a specific metabolic program elicited by c-MET inhibition. Interference with c-MET drives oxidative metabolism by increasing fatty acid oxidation (FAO) and glucose anaplerosis, which was orchestrated by the master-regulator, PGC1α. Based on a drug screen, we further found that the mitochondrial matrix chaperone inhibitor, gamitrinib, along with c-MET inhibition causes synergistic cell death, which was mechanistically related to the ability of gamitrinib to suppress oxidative metabolism. In alignment with these findings, FAO inhibitor, etomoxir, enhanced the anti-proliferative effects of c-MET inhibition as well. Both combination therapies were active in vivo, suggesting two novel potential combination therapies, involving c-MET inhibitors.
Project description:The receptor kinase c-MET has emerged as a target for glioblastoma therapy. However, treatment resistance emerges inevitably. Here, we performed global metabolite screening with metabolite set enrichment coupled with transcriptome and gene set enrichment analysis and proteomic screening, and identified substantial reprogramming of tumor metabolism involving oxidative phosphorylation and fatty acid oxidation (FAO) with substantial accumulation of acyl-carnitines accompanied by an increase of PGC1α in response to genetic (shRNA and CRISPR/Cas9) and pharmacologic (crizotinib) inhibition of c-MET. Extracellular flux and carbon tracing analyses (U-13C-glucose, U-13C-glutamine, and U-13C-palmitic acid) demonstrated enhanced oxidative metabolism, which was driven by FAO and supported by increased anaplerosis of glucose carbons. These findings were observed in concert with increased number and fusion of mitochondria and production of reactive oxygen species. Genetic interference with PGC1α rescued this oxidative phenotype driven by c-MET inhibition. Silencing and chromatin immunoprecipitation experiments demonstrated that cAMP response elements binding protein regulates the expression of PGC1α in the context of c-MET inhibition. Interference with both oxidative phosphorylation (metformin, oligomycin) and β-oxidation of fatty acids (etomoxir) enhanced the antitumor efficacy of c-MET inhibition. Synergistic cell death was observed with c-MET inhibition and gamitrinib treatment. In patient-derived xenograft models, combination treatments of crizotinib and etomoxir, and crizotinib and gamitrinib were significantly more efficacious than single treatments and did not induce toxicity. Collectively, we have unraveled the mechanistic underpinnings of c-MET inhibition and identified novel combination therapies that may enhance its therapeutic efficacy. SIGNIFICANCE: c-MET inhibition causes profound metabolic reprogramming that can be targeted by drug combination therapies.
Project description:Peroxisome proliferator-activated receptor (PPAR) γ coactivator 1α (PGC1α) is a coactivator of various nuclear receptors and other transcription factors that shows increased expression in skeletal muscle during exercise. In skeletal muscle, PGC1α is considered to be involved in contractile protein function, mitochondrial function, metabolic regulation, intracellular signaling, and transcriptional responses. Several isoforms of PGC1α mRNA have recently been identified. PGC1α-a is a full-length isoform of PGC1α that was the first to be isolated. PGC1α-b is another isoform of PGC1α, which is considered to be similar in function to PGC1α-a, differing by only 16 amino acids at the amino terminus. We have previously generated independent lines of transgenic mice that overexpress PGC1α-a or PGC1α-b in skeletal muscle. The microarray data shows that energy metabolism-related pathways such as the TCA cycle, branched-chain amino acid metabolism, purine nucleotide pathway, and malate–aspartate shuttle are activated in PGC1α transgenic mice compared with wild-type mice. For microarray analysis, RNA was isolated from the gastrocnemius skeletal muscle of wild-type control mice (12 weeks of age) as well as transgenic mice [PGC1α-a (E) (Miura et al., J. Biol. Chem. 278:31385-90, 2003), 12 weeks of age; PGC1α-b (02-1) (Miura et al., Endocrinology 149:4527-33, 2008), 14 weeks of age; and PGC1α-b (03-2) (Miura et al., Endocrinology 2008), 14 weeks of age]. Samples from wild-type and transgenic mice (N = 5 for each group) were pooled before use.
Project description:Eighteen independent neurospheres derived from patients affected by primary glioblastoma were grouped into “classical”, “mesenchymal” or “proneural” subtypes according to analysis of genetic lesions and gene expression profiling. Here we show that expression of the MET oncogene, encoding the tyrosine kinase receptor for HGF, associates with mesenchymal and proneural neurospheres (Met-pos-NS). Met expression is almost absent from classical neurospheres (Met-neg-NS), and mutually exclusive with amplification and expression of the EGF receptor gene. Met-pos-NS and Met-neg-NS display distinct growth factor requirements, differentiate along divergent pathways, and generate tumors with distinctive histological features. Met-pos-NS contain a variable percentage of Met positive (Methigh) and Met negative (Metneg) cells. After purification, only Methigh cells display clonogenic ability in vitro, and regenerate neurospheres containing both Methigh and Metneg cells. After in vivo transplantation, Methigh cells display highly enriched tumorigenic potential as compared with Metneg cells. At functional level, in Methigh cells, HGF concomitantly sustains proliferation, clonogenicity, expression of self-renewal markers, migration and invasion. These data show that Met is a functional marker of glioblastoma stem cells, and a candidate target for molecular diagnosis and therapy of a glioblastoma subset. 37 samples (17 replicate samples and 1 triplicate sample)
Project description:Eighteen independent neurospheres derived from patients affected by primary glioblastoma were grouped into “classical”, “mesenchymal” or “proneural” subtypes according to analysis of genetic lesions and gene expression profiling. Here we show that expression of the MET oncogene, encoding the tyrosine kinase receptor for HGF, associates with mesenchymal and proneural neurospheres (Met-pos-NS). Met expression is almost absent from classical neurospheres (Met-neg-NS), and mutually exclusive with amplification and expression of the EGF receptor gene. Met-pos-NS and Met-neg-NS display distinct growth factor requirements, differentiate along divergent pathways, and generate tumors with distinctive histological features. Met-pos-NS contain a variable percentage of Met positive (Methigh) and Met negative (Metneg) cells. After purification, only Methigh cells display clonogenic ability in vitro, and regenerate neurospheres containing both Methigh and Metneg cells. After in vivo transplantation, Methigh cells display highly enriched tumorigenic potential as compared with Metneg cells. At functional level, in Methigh cells, HGF concomitantly sustains proliferation, clonogenicity, expression of self-renewal markers, migration and invasion. These data show that Met is a functional marker of glioblastoma stem cells, and a candidate target for molecular diagnosis and therapy of a glioblastoma subset.
Project description:The current view of cellular transformation and cancer progression supports the notion that cancer cells must reprogram their metabolism in order to survive and progress in different microenvironments. Master co-regulators of metabolism orchestrate the modulation of multiple metabolic pathways through transcriptional programs, and hence constitute a probabilistically parsimonious mechanism for general metabolic rewiring. Here we show that the transcriptional co-activator PGC1α suppresses prostate cancer progression and metastasis. A metabolic co-regulator data mining analysis unveiled that PGC1α is consistently down-regulated in multiple prostate cancer patient datasets and its alteration is associated with reduced disease-free survival and metastasis. Genetically engineered mouse model studies revealed that compound prostate epithelium-specific deletion of Pgc1a and Pten promotes prostate cancer progression and metastasis, whereas, conversely, PGC1α expression in cell lines inhibits the pre-existing metastatic capacity. Through the application of integrative metabolomics and transcriptomics we demonstrate that PGC1α expression in prostate cancer is sufficient to elicit a global metabolic rewiring that opposes cell growth, consisting of sustained oxidative metabolism at the expense of anabolism. This metabolic program is regulated downstream the Oestrogen-related receptor alpha (ERRα), and PGC1α mutants lacking ERRα activation capacity lack metabolic rewiring capacity and metastasissuppressive function. Importantly, an ERRα signature in prostate cancer recapitulates the prognostic features of PGC1A. Our findings uncover an unprecedented causal contribution of PGC1α to the metabolic switch in prostate cancer and to the suppression of metastatic dissemination.
Project description:We described the metabolic alterations in glioblastoma model systems elicited by AURKA inhibition. By utilizing proteomic and transcriptomic analyses coupled with untargeted polar and nonpolar metabolite analysis by LC/MC, we found that AURKA inhibition leads to a profound reprogramming of tumor metabolism, which suppresses c-Myc protein levels and increases pro-survival PGC1α which in concert mediate a suppression of glycolysis and a concomitant activation of oxidative phosphorylation (OXPHOS) that is fueled by enhanced fatty acid oxidation (FAO). We targeted these metabolic aberrations with novel combination therapies involving clinical approved drugs in glioblastoma system both in vitro and in vivo. We used microarrays to detail the global programme of gene expression underlying cellularisation and identified distinct classes of up-regulated and down-regulated genes in Alisertib resistant cells.
Project description:Peroxisome proliferator-activated receptor (PPAR) γ coactivator 1α (PGC1α) is a coactivator of various nuclear receptors and other transcription factors that shows increased expression in skeletal muscle during exercise. In skeletal muscle, PGC1α is considered to be involved in contractile protein function, mitochondrial function, metabolic regulation, intracellular signaling, and transcriptional responses. Several isoforms of PGC1α mRNA have recently been identified. PGC1α-a is a full-length isoform of PGC1α that was the first to be isolated. PGC1α-b is another isoform of PGC1α, which is considered to be similar in function to PGC1α-a, differing by only 16 amino acids at the amino terminus. We have previously generated independent lines of transgenic mice that overexpress PGC1α-a or PGC1α-b in skeletal muscle. The microarray data shows that energy metabolism-related pathways such as the TCA cycle, branched-chain amino acid metabolism, purine nucleotide pathway, and malate–aspartate shuttle are activated in PGC1α transgenic mice compared with wild-type mice.