| 1. |
- Bhadury, Joydeep, et al.
(författare)
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Hypoxia-regulated gene expression explains differences between melanoma cell line-derived xenografts and patient-derived xenografts.
- 2016
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Ingår i: Oncotarget. - : Impact Journals, LLC. - 1949-2553. ; 7:17
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Tidskriftsartikel (refereegranskat)abstract
- Cell line-derived xenografts (CDXs) are an integral part of drug efficacy testing during development of new pharmaceuticals against cancer but their accuracy in predicting clinical responses in patients have been debated. Patient-derived xenografts (PDXs) are thought to be more useful for predictive biomarker identification for targeted therapies, including in metastatic melanoma, due to their similarities to human disease. Here, tumor biopsies from fifteen patients and ten widely-used melanoma cell lines were transplanted into immunocompromised mice to generate PDXs and CDXs, respectively. Gene expression profiles generated from the tumors of these PDXs and CDXs clustered into distinct groups, despite similar mutational signatures. Hypoxia-induced gene signatures and overexpression of the hypoxia-regulated miRNA hsa-miR-210 characterized CDXs. Inhibition of hsa-miR-210 with decoys had little phenotypic effect in vitro but reduced sensitivity to MEK1/2 inhibition in vivo, suggesting down-regulation of this miRNA could result in development of resistance to MEK inhibitors.
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| 2. |
- Podraza, Agnieszka, et al.
(författare)
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ENPL-1, the Caenorhabditis elegans homolog of GRP94, promotes insulin secretion via regulation of proinsulin processing and maturation
- 2020
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Ingår i: Development. - Cambridge : The Company of Biologists. - 1477-9129 .- 0950-1991. ; 147:20
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Tidskriftsartikel (refereegranskat)abstract
- © 2020. Published by The Company of Biologists Ltd. Insulin/IGF signaling in Caenorhabditis elegans is crucial for proper development of the dauer larva and growth control. Mutants disturbing insulin processing, secretion and downstream signaling perturb this process and have helped identify genes that affect progression of type 2 diabetes. Insulin maturation is required for its proper secretion by pancreatic β cells. The role of the endoplasmic reticulum (ER) chaperones in insulin processing and secretion needs further study. We show that the C. elegans ER chaperone ENPL-1/GRP94 (HSP90B1), acts in dauer development by promoting insulin secretion and signaling. Processing of a proinsulin likely involves binding between the two proteins via a specific domain. We show that, in enpl-1 mutants, an unprocessed insulin exits the ER lumen and is found in dense core vesicles, but is not secreted. The high ER stress in enpl-1 mutants does not cause the secretion defect. Importantly, increased ENPL-1 levels result in increased secretion. Taken together, our work indicates that ENPL-1 operates at the level of insulin availability and is an essential modulator of insulin processing and secretion.
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| 3. |
- Podraza-Farhanieh, Agnieszka, 1991, et al.
(författare)
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A proinsulin-dependent interaction between ENPL-1 and ASNA-1 in neurons is required to maintain insulin secretion in C. elegans.
- 2023
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Ingår i: Development (Cambridge, England). - : The Company of Biologists. - 1477-9129 .- 0950-1991. ; 150:6
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Tidskriftsartikel (refereegranskat)abstract
- Neuropeptides, including insulin, are important regulators of physiological functions of the organisms. Trafficking through the Golgi is crucial for the regulation of secretion of insulin-like peptides. ASNA-1 (TRC40) and ENPL-1 (GRP94) are conserved insulin secretion regulators in Caenorhabditis elegans (and mammals), and mouse Grp94 mutants display type 2 diabetes. ENPL-1/GRP94 binds proinsulin and regulates proinsulin levels in C. elegans and mammalian cells. Here, we have found that ASNA-1 and ENPL-1 cooperate to regulate insulin secretion in worms via a physical interaction that is independent of the insulin-binding site of ENPL-1. The interaction occurs in DAF-28/insulin-expressing neurons and is sensitive to changes in DAF-28 pro-peptide levels. Consistently, ASNA-1 acted in neurons to promote DAF-28/insulin secretion. The chaperone form of ASNA-1 was likely the interaction partner of ENPL-1. Loss of asna-1 disrupted Golgi trafficking pathways. ASNA-1 localization to the Golgi was affected in enpl-1 mutants and ENPL-1 overexpression partially bypassed the ASNA-1 requirement. Taken together, we find a functional interaction between ENPL-1 and ASNA-1 that is necessary to maintain proper insulin secretion in C. elegans and provides insights into how their loss might cause diabetes in mammals.
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| 4. |
- Podraza-Farhanieh, Agnieszka, 1991
(författare)
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Exploring mechanisms of insulin secretion regulators using C. elegans
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Diabetes mellitus is a group of disorders characterized by disrupted glucose homeostasis. Diabetes is one of the most dangerous diseases worldwide since it affects currently more than 500 million people. The pathogenesis of the disease is associated with the insufficient production of insulin and is characterized by increased blood glucose levels. Insulin secretion takes place in pancreatic β-cells in the response to elevated glucose levels and is regulated by various factors. This thesis is aimed to understand the functions of three proteins and characterize their novel roles in the regulation of insulin signaling and secretion. The first study showed the role of ENPL-1 in the positive regulation of insulin secretion. Loss of enpl-1 resulted in reduced insulin signaling and inhibited insulin secretion. Furthermore, we identified proinsulin as a novel client protein of ENPL-1 and showed that ENPL-1 was required for its maturation. The next study was based on the previous findings showing that ASNA-1 is a positive regulator of insulin secretion. Our study showed that ASNA-1 is present in two redox states, oxidized and reduced and that the multiple functions of ASNA-1 are dependent on its redox states. Our analysis showed, that forcing ASNA-1 into the oxidized state, reduced its function of inserting tail-anchored proteins into the endoplasmic reticulum, without affecting the insulin secretion function. In the next study, we focused on the mutual role of both previously mentioned proteins. We identified the interaction of ASNA-1 and ENPL-1 and showed that proinsulin is required for this interaction to take place. Our study indicated that oxidized ASNA-1 rather than the reduced form was likely interacting with ENPL-1. In the last study, we focused on the role of a third protein, SMN-1, and its impact on the regulation of insulin secretion. Our analysis showed that loss of SMN-1 resulted in neuropeptide secretion defect and caused redistribution of insulin from its original place. In summary, we characterized the functions of three proteins and indicated their importance in the regulation of insulin secretion processes.
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| 5. |
- Raj, Dorota, et al.
(författare)
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Alternative redox forms of ASNA-1 separate insulin signaling from tail-anchored protein targeting and cisplatin resistance in C. elegans
- 2021
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Cisplatin is a frontlinecancer therapeutic, but intrinsic or acquired resistance is common. We previouslyshowed that cisplatin sensitivity can be achieved by inactivation ofASNA-1/TRC40in mammalian cancer cells and inCaenorhabditiselegans. ASNA-1 has two more conservedfunctions: in promoting tail-anchored protein (TAP) targeting to theendoplasmicreticulum membrane and in promoting insulin secretion. However, the relationbetween its different functions has remained unknown. Here, we show that ASNA-1exists in two redox states that promote TAP-targeting and insulin secretion separately.The reduced state is the one required for cisplatin resistance: an ASNA-1 point mutant, in which the protein preferentially was found in the oxidized state, was sensitive to cisplatin and defective for TAP targeting but had no insulin secretion defect. The same was true for mutants inwrb-1,which we identifyas theC. eleganshomolog of WRB, the ASNA1/TRC40 receptor. Finally,we uncover a previously unknown action of cisplatin induced reactive oxygen species: cisplatin inducedROSdrives ASNA-1 into the oxidized form, andselectively prevents an ASNA-1-dependent TAP substrate from reaching the endoplasmicreticulum. Our work suggests that ASNA-1 acts as aredox-sensitive target forcisplatin cytotoxicity and that cisplatin resistance is likely mediated by ASNA-1-dependent TAP substrates. Treatments that promote an oxidizing tumor environmentshould be explored as possible means to combatcisplatin resistance. © 2021, The Author(s).
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| 6. |
- Raj, Dorota, et al.
(författare)
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Cisplatin toxicity is counteracted by the activation of the p38/ATF-7 signaling pathway in post-mitotic C. elegans
- 2023
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Ingår i: Nature Communications. - 2041-1723. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- Cisplatin kills proliferating cells via DNA damage but also has profound effects on post-mitotic cells in tumors, kidneys, and neurons. However, the effects of cisplatin on post-mitotic cells are still poorly understood. Among model systems, C. elegans adults are unique in having completely post-mitotic somatic tissues. The p38 MAPK pathway controls ROS detoxification via SKN-1/NRF and immune responses via ATF-7/ATF2. Here, we show that p38 MAPK pathway mutants are sensitive to cisplatin, but while cisplatin exposure increases ROS levels, skn-1 mutants are resistant. Cisplatin exposure leads to phosphorylation of PMK-1/MAPK and ATF-7 and the IRE-1/TRF-1 signaling module functions upstream of the p38 MAPK pathway to activate signaling. We identify the response proteins whose increased abundance depends on IRE-1/p38 MAPK activity as well as cisplatin exposure. Four of these proteins are necessary for protection from cisplatin toxicity, which is characterized by necrotic death. We conclude that the p38 MAPK pathway-driven proteins are crucial for adult cisplatin resilience. In contrast to mammalian cells, C. elegans models can be useful because of cells being post-mitotic in adults. Here the authors show activation of the p38 pathway in cisplatin resistant adult animals and characterise the proteins upstream and downstream of the p38 MAPK signalling pathway that are involved in the cisplatin response.
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| 7. |
- Raj, Dorota, et al.
(författare)
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Identification of C. elegans ASNA-1 domains and tissue requirements that differentially influence platinum sensitivity and growth control.
- 2022
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Ingår i: PLoS genetics. - : Public Library of Science (PLoS). - 1553-7404. ; 18:12
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Tidskriftsartikel (refereegranskat)abstract
- ASNA1 plays an essential role in cisplatin chemotherapy response, type 2 diabetes, and heart disease. It is also an important biomarker in the treatment response of many diseases. Biochemically, ASNA1 has two mutually exclusive redox-modulated roles: a tail-anchored protein (TAP) targeting function in the reduced state and a holdase/chaperone function in the oxidized state. Assigning biochemical roles of mammalian ASNA1 to biomedical functions is crucial for successful therapy development. Our previous work showed the relevance of the C. elegans ASNA-1 homolog in modeling cisplatin response and insulin secretion. Here we analyzed two-point mutants in highly conserved residues in C. elegans ASNA-1 and determined their importance in separating the cisplatin response function from its roles in insulin secretion. asna-1(ΔHis164) and asna-1(A63V) point mutants, which both preferentially exist in the oxidized state, displayed cisplatin sensitivity phenotype as well as TAP insertion defect but not an insulin secretion defect. Further, using targeted depletion we analyzed the tissue requirements of asna-1 for C. elegans growth and development. Somatic depletion of ASNA-1 as well as simultaneous depletion of ASNA-1 in neurons and intestines resulted in an L1 arrest. We concluded that, targeting single residues in ASNA-1 affecting Switch I/Switch II domain function, in comparison to complete knockdown counteracted cisplatin resistance without jeopardizing other important biological functions. Taken together, our study shows that effects on health caused by ASNA1 mutations can have different biochemical bases.
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