Metastatic progression of cancer is associated with poor outcome, and here we examine metabolic changes underlying this process. Although aerobic glycolysis is known to promote metastasis, we have ...now identified a different switch primarily affecting mitochondria. The switch involves overload of the electron transport chain (ETC) with preserved mitochondrial functions but increased mitochondrial superoxide production. It provides a metastatic advantage phenocopied by partial ETC inhibition, another situation associated with enhanced superoxide production. Both cases involved protein tyrosine kinases Src and Pyk2 as downstream effectors. Thus, two different events, ETC overload and partial ETC inhibition, promote superoxide-dependent tumor cell migration, invasion, clonogenicity, and metastasis. Consequently, specific scavenging of mitochondrial superoxide with mitoTEMPO blocked tumor cell migration and prevented spontaneous tumor metastasis in murine and human tumor models.
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•Tumor metastasis is under metabolic control•Both mitochondrial overload and mild respiration dysfunction promote metastasis•Mitochondrial superoxide promotes tumor cell migration, invasion, and clonogenicity•Scavenging mitochondrial superoxide prevents spontaneous tumor metastasis
Cancer is a leading cause of death worldwide and metastatic progression is associated with poor outcome. Porporato et al. have identified a metabolic switch that allows tumor cell mitochondria to drive successful metastatic progression. At the dissemination stage, some metastatic progenitor cells undergo a mitochondrial overload, whereas others experience a moderate respiration dysfunction. Both events promote superoxide-dependent metastasis. Consequently, mitochondria-specific superoxide scavenging inhibits metastatic dissemination, which opens a new avenue for therapeutic prevention.
The binding interactions of PD-1 and PD-L1 have been studied by surface plasmon resonance (SPR) and isothermal titration calorimetry (ITC) over the past few years, but these investigations resulted ...in controversy regarding the values of the dissociation constant (K
) ( Freeman
, 2000 ). MST is a powerful new method for the quantitative analysis of protein-protein interactions (PPIs) with low sample consumption. The technique is based on the movement of molecules along microscopic temperature gradients, and it detects changes in their hydration shell, charge or size. One binding partner is fluorescently labeled, while the other binding partner remains label-free. We used a protocol that allows the determination of the binding affinity by MST without purification of the target protein from the cell lysate. The application of this MST method to PD-1-eGFP and PD-L1-eGFP expressed in CHO-K1 cells allowed us, for the first time, to determine the affinity of the complex formed between PD-1 and its ligand PD-L1 during tumor escape. The protocol has a variety of potential applications for studying the interactions of proteins with small molecules.
Metabolic adaptability is essential for tumor progression and includes cooperation between cancer cells with different metabolic phenotypes. Optimal glucose supply to glycolytic cancer cells occurs ...when oxidative cancer cells use lactate preferentially to glucose. However, using lactate instead of glucose mimics glucose deprivation, and glucose starvation induces autophagy. We report that lactate sustains autophagy in cancer. In cancer cells preferentially to normal cells, lactate dehydrogenase B (LDHB), catalyzing the conversion of lactate and NAD+ to pyruvate, NADH and H+, controls lysosomal acidification, vesicle maturation, and intracellular proteolysis. LDHB activity is necessary for basal autophagy and cancer cell proliferation not only in oxidative cancer cells but also in glycolytic cancer cells.
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•Lactate supports lysosomal acidification and autophagy in cancer•Lactate oxidation by LDHB yields protons that fuel lysosomal V-ATPase•Targeting LDHB selectively blocks autophagy in oxidative and glycolytic cancer cells•Targeting LDHB is a promising anticancer approach
Brisson et al. show that lactate dehydrogenase B (LDHB) is critical for lysosomal activity and autophagy in cancer cells. Silencing LDHB selectively inhibits the proliferation of both oxidative and glycolytic cancer cells over normal cells, suggesting inhibition of LDHB as a promising anticancer approach.
Immuno-therapy has become a leading strategy to fight cancer. Over the past few years, immuno-therapies using checkpoint inhibitor monoclonal antibodies (mAbs) against programmed death receptor 1 ...(PD-1) and programmed death ligand 1 (PD-L1) have demonstrated improved survival compared with chemotherapy. We describe the microwave-assisted synthesis and the characterization of an innovative series of synthetic compounds endowed with nanomolar activity against PD-L1. The properties of the compounds were characterized using several biophysical techniques including microscale thermophoresis (MST) and fluorescence resonance energy transfer (FRET) measurements. A few small molecules demonstrated a high affinity for human PD-L1, potently disrupted the PD-L1:PD-1 interaction and inhibited Src homology region 2 domain-containing phosphatase (SHP2) recruitment to PD-1. More than 30 molecules from the pyrazolone family have been synthesized and 5 highly potent “PD-L1 silencing compounds” have been identified, based on in vitro measurements. Structure-activity relationships have been defined and ADME properties were evaluated. The phenyl-pyrazolone unit offers novel perspectives to design PD-L1-targeting agents, potentially useful to combat cancer and other pathologies implicating the PD-1/PD-L1 checkpoint.
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•PD-1/PD-L1 is a major immuno-checkpoint is oncology. Anti-PD-1/PD-L1 antibodies are used to treat cancer patients.•A novel family of pyrazolone-type small molecules targeting PD-L1 has been discovered.•We report the synthesis and characterization of 39 phenyl-pyrazolone derivatives and their activities against PD-L1.•Compounds targeting PD-L1 with nanomolar affinities have been designed and structure-activity relationships are described.
Abstract
Immuno-therapy has become a leading strategy to fight cancer. Over the past few years, immuno-therapies using checkpoint inhibitor monoclonal antibodies (mAbs) against programmed death ...receptor 1 (PD-1) and programmed death ligand 1 (PD-L1) have demonstrated improved survival compared with chemotherapy. We describe the identification and characterization of an innovative series of synthetic compounds (named PyrDLones, patented) endowed with nanomolar activity against PD-L1. PyrDLones properties were characterized using several biophysical techniques including microscale thermophoresis (MST) and fluorescence resonance energy transfer (FRET) measurements. In vitro, selected small molecules demonstrate a high affinity for human PD-L1, potently disrupt the PD-L1:PD-1 interaction (<2nM), and inhibit Src homology region 2 domain-containing phosphatase (SHP2) recruitment to PD-1 (<4nM). As a result, upon binding to and inhibiting PD-L1, these molecules reactivate proliferation of CTL-L2 cells expressing PD-1 (EC50=44nM). More than 150 molecules have been synthesized and a dozen of highly potent “PD-L1 silencing compounds” have been identified, based on in vitro measurements. Structure-activity relationships have been defined and an in silico drug-target model supporting the mechanism of action has been built. Experiments are on-going to delineate further the molecular mechanism of action of the PyrDLones (drug-induced PD-L1 dimer formation), the cellular consequences of the PD-L1 silencing (reactivation of cytotoxic T cells in the tumor microenvironment) and to characterize their activity in vivo. In summary, we have discovered a novel series of potent, small molecule PD-L1 antagonists, amenable to the design of orally active drugs for immuno-therapy of cancers.
Citation Format: Romain Magnez, Natascha Leleu-Chavain, Morgane Tardy, Hassiba El Bouazzati, Fréderique Klupsch, Christian Bailly, Régis Millet, Bruno Quesnel, Xavier Thuru. Novel small-molecule antagonists of the PD1/PD-L1 axis abstract. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5340.
The Wnt signaling pathway controls multiple events during embryonic development of multicellular animals and is carcinogenic when aberrantly activated in adults. Breast cancers are dependent on Wnt ...pathway overactivation mostly through dysregulation of pathway component protein expression, which necessitates the search for therapeutically relevant compounds targeting them. Highly diverse microorganisms as endophytes represent an underexplored field in the therapeutic natural products research. In the present work, the objective was to explore the chemical diversity and presence of selective Wnt inhibitors within a unique collection of fungi isolated as foliar endophytes from the long-lived tropical palm
Astrocaryum sciophilum
. The fungi were cultured, extracted with ethyl acetate, and screened for their effects on the Wnt pathway and cell proliferation. The endophytic strain
Lasiodiplodia venezuelensis
was prioritized for scaled-up fractionation based on its selective activity. Application of geometric transfer from analytical HPLC conditions to semi-preparative scale and use of dry load sample introduction enabled the isolation of 15 pure compounds in a single step. Among the molecules identified, five are original natural products described for the first time, and six are new to this species. An active fraction obtained by semi-preparative HPLC was re-purified by UHPLC-PDA using a 1.7 µm phenyl column. 75 injections of 8 µg were necessary to obtain sufficient amounts of each compound for structure elucidation and bioassays. Using this original approach, in addition to the two major compounds, a third minor compound identified as (
R
)-(-)-5-hydroxymellein (18) was obtained, which was found to be responsible for the significant Wnt inhibition activity recorded. Further studies of this compound and its structural analogs showed that only 18 acts in a highly specific manner, with no acute cytotoxicity. This compound is notably selective for upstream components of the Wnt pathway and is able to inhibit the proliferation of three triple negative breast cancer cell lines. In addition to the discovery of Wnt inhibitors of interest, this study contributes to better characterize the biosynthetic potential of
L. venezuelensis
.
Abstract Background Protein S (PS) is an essential component of the protein C pathway and PS deficiency can explain a poor response to activated protein C. It has recently been shown that PS also ...acts as a cofactor of Tissue Factor Pathway Inhibitor (TFPI). Objectives In the present study, we investigated whether PS deficiency could be responsible for a poor response to TFPI. Patients/Methods Thirty-one patients with inherited PS deficiency, seven pregnant women and 36 controls were enrolled in the study. We measured the plasma response to added TFPI using a two-step diluted prothrombin time (dPT) assay. The response of the different plasmas to the anticoagulant activity of TFPI was expressed as TFPI Normalised Ratio (TFPI NR). Results The median TFPI NR was statistically significantly lower in patients with inherited PS deficiency (0.5) than in controls (1.0) (p < 0.0001). It was statistically significantly lower in patients with type I inherited PS deficiency (0.47) compared to patients with type III inherited PS deficiency (0.58) (p = 0.018). In contrast, it did not differ between patients with and without thrombosis. Median TFPI NR values were statistically significantly lower during pregnancy (0.54) than 3 months after delivery (0.71) (p = 0.016). TFPI NR values correlated well with PS activity values (R2 = 0.681) whatever the nature of the PS deficiency. Conclusions Our findings confirm that PS deficiency results in a poor anticoagulant response to TFPI, demonstrating again the cofactor role of PS in TFPI activity.
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