DHODH inhibition modulates glucose metabolism and circulating GDF15, and improves metabolic balance

Dihydroorotate dehydrogenase (DHODH) is essential for the de novo synthesis of pyrimidine ribonucleotides, and as such, its inhibitors have been long used to treat autoimmune diseases and are in clinical trials for cancer and viral infections. Interestingly, DHODH is located in the inner mitochondrial membrane and contributes to provide ubiquinol to the respiratory chain. Thus, DHODH provides the link between nucleotide metabolism and mitochondrial function. Here we show that pharmacological inhibition of DHODH reduces mitochondrial respiration, promotes glycolysis, and enhances GLUT4 translocation to the cytoplasmic membrane and that by activating tumor suppressor p53, increases the expression of GDF15, a cytokine that reduces appetite and prolongs lifespan. In addition, similar to the antidiabetic drug metformin, we observed that in db/db mice, DHODH inhibitors elevate levels of circulating GDF15 and reduce food intake. Further analysis using this model for obesity-induced diabetes revealed that DHODH inhibitors delay pancreatic β cell death and improve metabolic balance.publishedVersio

A DHODH inhibitor increases p53 synthesis and enhances tumor cell killing by p53 degradation blockage

ML, CD, IvL, GP, TM, SD, MS, APF, CT, DL, MAH, KL and SL: project grants from the Swedish Research Council, the Swedish Cancer Society and the Swedish Childhood Cancer Foundation. MHi and JC: Cancer Research UK (C8/A6613). MC, EP and WE: Wellcome Trust (073915). MN and BV: projects MEYS-NPS-LO1413 and GACR P206/12/G151. EMC, MP, MMS, ZF and PG: Norwegian Cancer Society (182735, 732200) and Helse Vest (911884, 911789). RB and SC: NIH (R01 CA95684), the Leukemia and Lymphoma Society and the Waxman Foundation. NW, AH, Ad’H: Cancer Research UK (C21383/A6950) and Engineering and Physical Sciences Research Council Doctoral Training Program. JL and YZ: Cancer Research UK (C240/A15751). MH and BW: SARomics Biostructures ABUY, KF: DDDP SciLife, Sweden. LJ, MHa, RS and A-LG: CBCS, Sweden. VP: SciLife fellowship. AT: Breast Cancer Research Scotland.The development of non-genotoxic therapies that activate wild-type p53 in tumors is of great interest since the discovery of p53 as a tumor suppressor. Here we report the identification of over 100 small-molecules activating p53 in cells. We elucidate the mechanism of action of a chiral tetrahydroindazole (HZ00), and through target deconvolution, we deduce that its active enantiomer (R)-HZ00, inhibits dihydroorotate dehydrogenase (DHODH). The chiral specificity of HZ05, a more potent analog, is revealed by the crystal structure of the (R)-HZ05/DHODH complex. Twelve other DHODH inhibitor chemotypes are detailed among the p53 activators, which identifies DHODH as a frequent target for structurally diverse compounds. We observe that HZ compounds accumulate cancer cells in S-phase, increase p53 synthesis, and synergize with an inhibitor of p53 degradation to reduce tumor growth in vivo. We, therefore, propose a strategy to promote cancer cell killing by p53 instead of its reversible cell cycle arresting effect.Publisher PDFPeer reviewe

Design, synthesis and in vitro evaluation of novel anti-cancer compounds

THESIS 7335The purpose of this thesis was the design, synthesis and in vitro appraisal of a novel class of ITP/APN dual inhibitory compounds. Additionally, a class of novel biaryls, which were synthesised within the research group, were assayed to evaluate their ability to inhibit tubulin polymerisation (ITP). The introductory chapter commences with brief overview of the history of cancer and role of natural products in conventional chemotherapeutic regimes and adjuvant immunotherapies. Subsequently, the biological mechanisms of mitosis and metastasis are discussed with special emphasis on the importance of tubulin and the spindle apparatus, and the proteolytic degradation of the extracellular matrix by the angiogenic marker, aminopeptidase N (APN). Following, a review of the structural activity requisites of particular aminopeptidase N and antimitotic compounds, a discussion on the novel development of a novel class of dual ITP/APN inhibitory compoimds ensues. The chapter concludes with the rationalisation of the proposed synthetic strategies, and the obligatory development of tubulin extraction, purification and assay procedures. Chapter 2 proceeds with the synthesis a series of investigational compounds coupling colchicbe to several dicarboxylic amino acids and (2S.3R)-2-hydroxy-3-amino-4- phenylbutanoic acid (AHPA), probing the optimum chain length compulsory to fulfil both requirements of minimal disruption to ITP whilst maintaining fianctionality necessary for APN/CD13 inhibition. Consequent ITP in vitro assay results are analysed and the importance of Aspartic acid (Asp) as a linker molecule discussed

High expression of the p53 isoform γ is associated with reduced progression-free survival in uterine serous carcinoma

Abstract Background Uterine serous carcinoma (USC) is a rare but aggressive subtype of endometrial carcinoma. Large-scale comprehensive efforts have resulted in an improved molecular understanding of its pathogenesis, and the p53 pathway has been proposed as a key player and is potentially targetable. Here we attempt to further portray the p53 pathway in USC by assessing p53 isoform expression. Methods We applied quantitative Real-Time PCRs (RT-qPCR) for expression analyses of total p53 mRNA as well as quantitative distinction of p53β, p53γ, and the total mRNA of amino-terminal truncated Δ40p53 and Δ133p53 in a retrospective cohort of 37 patients with USC. TP53 mutation status was assessed by targeted massive parallel sequencing. Findings were correlated with clinical data. Results The p53 isoform expression landscape in USCs was heterogeneous and dominated by total Δ133p53, while the distinct p53β and p53γ variants were found at much lower levels. The isoform expression profiles varied between samples, while their expression was independent of TP53 mutation status. We found high relative p53γ expression to be associated with reduced progression-free survival (PFS). Conclusions This is the first indication that elevated p53γ expression is associated with reduced PFS in USC. This single-center study may offer some insight in the landscape of p53 isoform expression in USC, but further validation studies are crucial to understand the context-dependent and tissue-specific role of the p53 isoform network in gynecological cancer

A human clinical trial using ultrasound and microbubbles to enhance gemcitabine treatment of inoperable pancreatic cancer

Background: The primary aim of our study was to evaluate the safety and potential toxicity of gemcitabine combined with microbubbles under sonication in inoperable pancreatic cancer patients. The secondary aim was to evaluate a novel image-guided microbubble-based therapy, based on commercially available technology, towards improving chemotherapeutic efficacy, preserving patient performance status, and prolonging survival. Methods: Ten patients were enrolled and treated in this Phase I clinical trial. Gemcitabine was infused intravenously over 30 min. Subsequently, patients were treated using a commercial clinical ultrasound scanner for 31.5 min. SonoVue® was injected intravenously (0.5 ml followed by 5 ml saline every 3.5 min) during the ultrasound treatment with the aim of inducing sonoporation, thus enhancing therapeutic efficacy. Results: The combined therapeutic regimen did not induce any additional toxicity or increased frequency of side effects when compared to gemcitabine chemotherapy alone (historical controls). Combination treated patients (n = 10) tolerated an increased number of gemcitabine cycles compared with historical controls (n = 63 patients; average of 8.3 ± 6.0 cycles, versus 13.8 ± 5.6 cycles, p = 0.008, unpaired t-test). In five patients, the maximum tumour diameter was decreased from the first to last treatment. The median survival in our patients (n = 10) was also increased from 8.9 months to 17.6 months (p = 0.011). Conclusions: It is possible to combine ultrasound, microbubbles, and chemotherapy in a clinical setting using commercially available equipment with no additional toxicities. This combined treatment may improve the clinical efficacy of gemcitabine, prolong the quality of life, and extend survival in patients with pancreatic ductal adenocarcinoma

DHODH inhibition modulates glucose metabolism and circulating GDF15, and improves metabolic balance

Dihydroorotate dehydrogenase (DHODH) is essential for the de novo synthesis of pyrimidine ribonucleotides, and as such, its inhibitors have been long used to treat autoimmune diseases and are in clinical trials for cancer and viral infections. Interestingly, DHODH is located in the inner mitochondrial membrane and contributes to provide ubiquinol to the respiratory chain. Thus, DHODH provides the link between nucleotide metabolism and mitochondrial function. Here we show that pharmacological inhibition of DHODH reduces mitochondrial respiration, promotes glycolysis, and enhances GLUT4 translocation to the cytoplasmic membrane and that by activating tumor suppressor p53, increases the expression of GDF15, a cytokine that reduces appetite and prolongs lifespan. In addition, similar to the antidiabetic drug metformin, we observed that in db/db mice, DHODH inhibitors elevate levels of circulating GDF15 and reduce food intake. Further analysis using this model for obesity-induced diabetes revealed that DHODH inhibitors delay pancreatic β cell death and improve metabolic balance

Stabilization of β-catenin upon B-cell receptor signaling promotes NF-kB target genes transcription in mantle cell lymphoma

International audienceB-cell receptor (BCR) signaling pathways and interactions with the tumor microenvironment account for mantle cell lymphoma (MCL) cells survival in lymphoid organs. In several MCL cases, the WNT/β-catenin canonical pathway is activated and β-catenin accumulates into the nucleus. As both BCR and β-catenin are important mediators of cell survival and interaction with the microenvironment, we investigated the crosstalk between BCR and WNT/β-catenin signaling and analyzed their impact on cellular homeostasis as well as their targeting by specific inhibitors. β-catenin was detected in all leukemic MCL samples and its level of expression rapidly increased upon BCR stimulation. This stabilization was hampered by the BCR-pathway inhibitor Ibrutinib, supporting β-catenin as an effector of the BCR signaling. In parallel, MCL cells as compared with normal B cells expressed elevated levels of WNT16, a NF-κB target gene. Its expression increased further upon BCR stimulation to participate to the stabilization of β-catenin. Upon BCR stimulation, β-catenin translocated into the nucleus but did not induce a Wnt-like transcriptional response, i.e., TCF/LEF dependent. β-catenin rather participated to the regulation of NF-κB transcriptional targets, such as IL6, IL8, and IL1. Oligo pull down and chromatin immunoprecipitation experiments demonstrated that β-catenin is part of a protein complex that binds the NF-κB DNA consensus sequence, strengthening the idea of an association between the two proteins. An inhibitor targeting β-catenin transcriptional interactions hindered both NF-κB DNA recruitment and induced primary MCL cells apoptosis. Thus, β-catenin likely represents another player through which BCR signaling impacts on MCL cell survival

A DHODH inhibitor increases p53 synthesis and enhances tumor cell killing by p53 degradation blockage

The development of non-genotoxic therapies that activate wild-type p53 in tumors is of great interest since the discovery of p53 as a tumor suppressor. Here we report the identification of over 100 small-molecules activating p53 in cells. We elucidate the mechanism of action of a chiral tetrahydroindazole (HZ00), and through target deconvolution, we deduce that its active enantiomer (R)-HZ00, inhibits dihydroorotate dehydrogenase (DHODH). The chiral specificity of HZ05, a more potent analog, is revealed by the crystal structure of the (R)-HZ05/DHODH complex. Twelve other DHODH inhibitor chemotypes are detailed among the p53 activators, which identifies DHODH as a frequent target for structurally diverse compounds. We observe that HZ compounds accumulate cancer cells in S-phase, increase p53 synthesis, and synergize with an inhibitor of p53 degradation to reduce tumor growth in vivo. We, therefore, propose a strategy to promote cancer cell killing by p53 instead of its reversible cell cycle arresting effect