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1.
J Cell Biol ; 221(2)2022 02 07.
Article in English | MEDLINE | ID: mdl-34935867

ABSTRACT

Cancer patients frequently develop chemotherapy-induced peripheral neuropathy (CIPN), a painful and long-lasting disorder with profound somatosensory deficits. There are no effective therapies to prevent or treat this disorder. Pathologically, CIPN is characterized by a "dying-back" axonopathy that begins at intra-epidermal nerve terminals of sensory neurons and progresses in a retrograde fashion. Calcium dysregulation constitutes a critical event in CIPN, but it is not known how chemotherapies such as paclitaxel alter intra-axonal calcium and cause degeneration. Here, we demonstrate that paclitaxel triggers Sarm1-dependent cADPR production in distal axons, promoting intra-axonal calcium flux from both intracellular and extracellular calcium stores. Genetic or pharmacologic antagonists of cADPR signaling prevent paclitaxel-induced axon degeneration and allodynia symptoms, without mitigating the anti-neoplastic efficacy of paclitaxel. Our data demonstrate that cADPR is a calcium-modulating factor that promotes paclitaxel-induced axon degeneration and suggest that targeting cADPR signaling provides a potential therapeutic approach for treating paclitaxel-induced peripheral neuropathy (PIPN).


Subject(s)
Armadillo Domain Proteins/metabolism , Axons/metabolism , Calcium/metabolism , Cyclic ADP-Ribose/metabolism , Cytoskeletal Proteins/metabolism , Nerve Degeneration/pathology , Paclitaxel/adverse effects , Peripheral Nervous System Diseases/chemically induced , Peripheral Nervous System Diseases/metabolism , Animals , Calcium Channels/metabolism , Cyclic ADP-Ribose/antagonists & inhibitors , Female , HEK293 Cells , Humans , Mice, Inbred C57BL , Rats, Sprague-Dawley
2.
Mol Cancer Ther ; 20(1): 64-75, 2021 01.
Article in English | MEDLINE | ID: mdl-33087508

ABSTRACT

Small cell carcinoma of the ovary, hypercalcemic type (SCCOHT) is a rare but often lethal cancer that is diagnosed at a median age of 24 years. Optimal management of patients is not well defined, and current treatment remains challenging, necessitating the discovery of novel therapeutic approaches. The identification of SMARCA4-inactivating mutations invariably characterizing this type of cancer provided insights facilitating diagnostic and therapeutic measures against this disease. We show here that the BET inhibitor OTX015 acts in synergy with the MEK inhibitor cobimetinib to repress the proliferation of SCCOHT in vivo Notably, this synergy is also observed in some SMARCA4-expressing ovarian adenocarcinoma models intrinsically resistant to BETi. Mass spectrometry, coupled with knockdown of newly found targets such as thymidylate synthase, revealed that the repression of a panel of proteins involved in nucleotide synthesis underlies this synergy both in vitro and in vivo, resulting in reduced pools of nucleotide metabolites and subsequent cell-cycle arrest. Overall, our data indicate that dual treatment with BETi and MEKi represents a rational combination therapy against SCCOHT and potentially additional ovarian cancer subtypes.


Subject(s)
Epigenesis, Genetic , Mitogen-Activated Protein Kinases/antagonists & inhibitors , Nucleotides/metabolism , Protein Kinase Inhibitors/pharmacology , Animals , Azetidines/pharmacology , Cell Cycle Checkpoints/drug effects , Cell Line, Tumor , Cell Proliferation/drug effects , Down-Regulation/drug effects , Drug Synergism , Epigenesis, Genetic/drug effects , Female , Gene Knockdown Techniques , HEK293 Cells , Humans , Mice, Inbred NOD , Mice, SCID , Mitogen-Activated Protein Kinase Kinases/antagonists & inhibitors , Mitogen-Activated Protein Kinase Kinases/metabolism , Mitogen-Activated Protein Kinases/metabolism , Neoplasm Proteins/metabolism , Ovarian Neoplasms/drug therapy , Piperidines/pharmacology , Protein Kinase Inhibitors/therapeutic use , S Phase/drug effects , Xenograft Model Antitumor Assays
3.
Cell Rep ; 32(12): 108170, 2020 09 22.
Article in English | MEDLINE | ID: mdl-32966787

ABSTRACT

The replication cycle and pathogenesis of the Plasmodium malarial parasite involves rapid expansion in red blood cells (RBCs), and variants of certain RBC-specific proteins protect against malaria in humans. In RBCs, bisphosphoglycerate mutase (BPGM) acts as a key allosteric regulator of hemoglobin/oxyhemoglobin. We demonstrate here that a loss-of-function mutation in the murine Bpgm (BpgmL166P) gene confers protection against both Plasmodium-induced cerebral malaria and blood-stage malaria. The malaria protection seen in BpgmL166P mutant mice is associated with reduced blood parasitemia levels, milder clinical symptoms, and increased survival. The protective effect of BpgmL166P involves a dual mechanism that enhances the host's stress erythroid response to Plasmodium-driven RBC loss and simultaneously alters the intracellular milieu of the RBCs, including increased oxyhemoglobin and reduced energy metabolism, reducing Plasmodium maturation, and replication. Overall, our study highlights the importance of BPGM as a regulator of hemoglobin/oxyhemoglobin in malaria pathogenesis and suggests a new potential malaria therapeutic target.


Subject(s)
Anemia/etiology , Anemia/prevention & control , Bisphosphoglycerate Mutase/deficiency , Malaria, Cerebral/enzymology , Malaria, Cerebral/prevention & control , Amino Acid Sequence , Amino Acid Substitution , Animals , Base Sequence , Bisphosphoglycerate Mutase/chemistry , Bisphosphoglycerate Mutase/genetics , Bisphosphoglycerate Mutase/metabolism , Enzyme Stability , Erythrocytes/enzymology , Erythrocytes/parasitology , Erythropoiesis , Extracellular Matrix/metabolism , Female , HEK293 Cells , Humans , Malaria, Cerebral/complications , Male , Mice , Mice, Inbred C57BL , Mice, Mutant Strains , Mutation/genetics , Parasites/growth & development , Plasmodium/growth & development , Polycythemia
4.
Anal Methods ; 3(3): 552-556, 2011 Mar 01.
Article in English | MEDLINE | ID: mdl-32938071

ABSTRACT

The citrus greening (or huanglongbing) disease has caused serious problems in citrus crops around the world. An early diagnostic method to detect this malady is needed due to the rapid dissemination of Candidatus Liberibacter asiaticus (CLas) in the field. This analytical study investigated the fluorescence responses of leaves from healthy citrus plants and those inoculated with CLas by images from a stereomicroscope and also evaluated their potential for the early diagnosis of the infection caused by this bacterium. The plants were measured monthly, and the evolution of the bacteria on inoculated plants was monitored by real-time quantitative polymerase chain reaction (RT-qPCR) amplification of CLas sequences. A statistical method was used to analyse the data. The selection of variables from histograms of colours (colourgrams) of the images was optimized using a paired Student's t-test. The intensity of counts for green colours from images of fluorescence had clearly minor variations for healthy plants than diseased ones. The darker green colours were the indicators of healthy plants and the light colours for the diseased. The method of fluorescence images is novel for fingerprinting healthy and diseased plants and provides an alternative to the current method represented by PCR and visual inspection. A new, non-subjective pattern of analysis and a non-destructive method has been introduced that can minimize the time and costs of analyses.

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