scholarly journals The structure-function relationship of oncogenic LMTK3

2020 ◽  
Vol 6 (46) ◽  
pp. eabc3099
Author(s):  
Angeliki Ditsiou ◽  
Chiara Cilibrasi ◽  
Nikiana Simigdala ◽  
Athanasios Papakyriakou ◽  
Leanne Milton-Harris ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Heat Shock Protein 90 ◽  
Kinase Domain ◽  
Time Resolved ◽  
Molecule Inhibitor ◽  
Effective Doses ◽  
Function Relationship ◽  
Relationship Of

Elucidating signaling driven by lemur tyrosine kinase 3 (LMTK3) could help drug development. Here, we solve the crystal structure of LMTK3 kinase domain to 2.1Å resolution, determine its consensus motif and phosphoproteome, unveiling in vitro and in vivo LMTK3 substrates. Via high-throughput homogeneous time-resolved fluorescence screen coupled with biochemical, cellular, and biophysical assays, we identify a potent LMTK3 small-molecule inhibitor (C28). Functional and mechanistic studies reveal LMTK3 is a heat shock protein 90 (HSP90) client protein, requiring HSP90 for folding and stability, while C28 promotes proteasome-mediated degradation of LMTK3. Pharmacologic inhibition of LMTK3 decreases proliferation of cancer cell lines in the NCI-60 panel, with a concomitant increase in apoptosis in breast cancer cells, recapitulating effects of LMTK3 gene silencing. Furthermore, LMTK3 inhibition reduces growth of xenograft and transgenic breast cancer mouse models without displaying systemic toxicity at effective doses. Our data reinforce LMTK3 as a druggable target for cancer therapy.

scholarly journals New multiscale characterisation methodology for effective determination of isolation-structure-function relationship of extracellular vesicles

2021 ◽  
Author(s):  
Thanh Huyen Phan ◽  
Shiva Kamini Divakarla ◽  
Jia Hao Yeo ◽  
Qingyu Lei ◽  
Priyanka Tharkar ◽  
...  
Keyword(s):  
Extracellular Vesicles ◽  
Biological Effects ◽  
Dry Mass ◽  
Experimental Methodology ◽  
Wide Range ◽  
Isolation Methods ◽  
Function Relationship ◽  
Relationship Of

AbstractExtracellular vesicles (EVs) have been lauded as next generation medicines, but very few EV-based therapeutics have progressed to clinical use. Limited clinical translation is largely due to technical barriers that hamper our ability to mass-produce EVs, i.e. to isolate, purify and characterise them effectively. Technical limitations in comprehensive characterisation of EVs leads to unpredicted biological effects of EVs. Here, using a range of optical and non-optical techniques, we showed that the differences in molecular composition of EVs isolated using two isolation methods correlated with the differences in their biological function. Our results demonstrated that the isolation method determines the composition of isolated EVs at single and sub-population levels. Besides the composition, we measured for the first time the dry mass and predicted sedimentation of EVs. These parameters were shown to correlate well with the biological and functional effects of EVs on single cell and cell cultures. We anticipate that our new multiscale characterisation approach, which goes beyond traditional experimental methodology, will support fundamental understanding of EVs as well as elucidate the functional effects of EVs in in vitro and in vivo studies. Our findings and methodology will be pivotal for developing optimal isolation methods and establishing EVs as mainstream therapeutics and diagnostics. This innovative approach is applicable to a wide range of sectors including biopharma and biotechnology as well as to regulatory agencies.

scholarly journals Insights on the Quest for the Structure–Function Relationship of the Mitochondrial Pyruvate Carrier

Biology ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 407
Author(s):  
José Edwin Neciosup Quesñay ◽  
Naomi L. Pollock ◽  
Raghavendra Sashi Krishna Nagampalli ◽  
Sarah C. Lee ◽  
Vijayakumar Balakrishnan ◽  
...  
Keyword(s):  
Molecular Structures ◽  
Computational Tools ◽  
Protein Subunits ◽  
Molecular Identity ◽  
Current State ◽  
Mitochondrial Pyruvate Carrier ◽  
Function Relationship ◽  
Relationship Of

The molecular identity of the mitochondrial pyruvate carrier (MPC) was presented in 2012, forty years after the active transport of cytosolic pyruvate into the mitochondrial matrix was first demonstrated. An impressive amount of in vivo and in vitro studies has since revealed an unexpected interplay between one, two, or even three protein subunits defining different functional MPC assemblies in a metabolic-specific context. These have clear implications in cell homeostasis and disease, and on the development of future therapies. Despite intensive efforts by different research groups using state-of-the-art computational tools and experimental techniques, MPCs’ structure-based mechanism remains elusive. Here, we review the current state of knowledge concerning MPCs’ molecular structures by examining both earlier and recent studies and presenting novel data to identify the regulatory, structural, and core transport activities to each of the known MPC subunits. We also discuss the potential application of cryogenic electron microscopy (cryo-EM) studies of MPC reconstituted into nanodiscs of synthetic copolymers for solving human MPC2.

scholarly journals Modular Structure of PACT: Distinct Domains for Binding and Activating PKR

2001 ◽  
Vol 21 (6) ◽  
pp. 1908-1920 ◽  
Author(s):  
Gregory A. Peters ◽  
Rune Hartmann ◽  
Jun Qin ◽  
Ganes C. Sen
Keyword(s):  
Protein Domain ◽  
Affinity Binding ◽  
Translation Inhibition ◽  
High Affinity ◽  
Cellular Apoptosis ◽  
Domain 3 ◽  
Function Relationship ◽  
Relationship Of

ABSTRACT PACT is a 35-kDa human protein that can directly bind and activate the latent protein kinase, PKR. Here we report that PKR activation by PACT causes cellular apoptosis in addition to PKR autophosphorylation and translation inhibition. We analyzed the structure-function relationship of PACT by measuring its ability to bind and activate PKR in vitro and in vivo. Our studies revealed that among three domains of PACT, the presence of either domain 1 or domain 2 was sufficient for high-affinity binding of PACT to PKR. On the other hand, domain 3, consisting of 66 residues, was absolutely required for PKR activation in vitro and in vivo. When fused to maltose-binding protein, domain 3 was also sufficient for efficiently activating PKR in vitro. However, it bound poorly to PKR at the physiological salt concentration and consequently could not activate it properly in vivo. As anticipated, activation of PKR by domain 3 in vivo could be restored by attaching it to a heterologous PKR-binding domain. These results demonstrated that the structure of PACT is modular: it is composed of a distinct PKR-activation domain and two mutually redundant PKR-interacting domains.

scholarly journals Characterizing the structure-function relationship of a naturally-occurring RNA thermometer

2017 ◽  
Author(s):  
Sarai Meyer ◽  
Julius B. Lucks
Keyword(s):  
Heat Shock ◽  
Rna Structure ◽  
Structural Changes ◽  
Structural Motif ◽  
Ribosome Binding ◽  
Heat Shock Responses ◽  
Function Relationship ◽  
Relationship Of

AbstractA wide number of bacteria have been found to govern virulence and heat shock responses using temperature-sensing RNAs known as RNA thermometers. A prime example is theagsAthermometer known to regulate the production of the AgsA heat shock protein inSalmonella entericausing a “fourU” structural motif. Using the SHAPE-Seq RNA structure-probing methodin vivoandin vitro, we found that the regulator functions by a subtle shift in equilibrium RNA structure populations that lead to a partial melting of the helix containing the ribosome binding site. We also demonstrate that ribosome binding to theagsAmRNA causes changes to the thermometer structure that appear to facilitate thermometer helix unwinding. These results demonstrate how subtle RNA structural changes can govern gene expression and illuminate the function of an important bacterial regulatory motif.

scholarly journals Tumor suppressor PLK2 may serve as a biomarker in triple-negative breast cancer for improved response to PLK1 therapeutics

2021 ◽  
Author(s):  
Yang Gao ◽  
Elena B Kabotyanski ◽  
Elizabeth Villegas ◽  
Jonathan H. Shepherd ◽  
Deanna Acosta ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Triple Negative Breast Cancer ◽  
Triple Negative ◽  
Kinase Domain ◽  
Null Mouse ◽  
Mouse Tumor ◽  
Breast Cancers ◽  
Cancer Subtypes

Polo-like kinase (PLK) family members play important roles in cell cycle regulation. The founding member PLK1 is oncogenic and preclinically validated as a cancer therapeutic target. Paradoxically, PLK2 (chromosome 5q11.2) is frequently deleted in human breast cancers, preferentially in basal-like and triple-negative breast cancer subtypes. Here, we found that PLK2 was tumor suppressive in breast cancer and knockdown of PLK1 rescued phenotypes induced by PLK2-loss both in vitro and in vivo. We also demonstrated that PLK2 directly interacted with PLK1 at prometaphase and that mutations in the kinase domain of PLK2, but not polo-box binding domains, changed their interaction pattern. Furthermore, treatment of syngeneic transplantation mouse tumor models and patient-derived xenografts using the PLK1 inhibitor volasertib alone, or in combination with carboplatin, indicated that PLK2-low breast tumors had a significantly better response to these drugs. Re-expression of PLK2 in an inducible PLK2-null mouse model reduced the therapeutic efficacy of volasertib. Taken together, our data suggest PLK2 loss may serve as a biomarker to predict response to PLK1 therapeutics, alone and in combination with chemotherapy.

scholarly journals Auranofin and ICG-001 Emerge Synergistic Anti-tumor Effect on Canine Breast Cancer by Inducing Apoptosis via Mitochondrial Pathway

2021 ◽  
Vol 8 ◽  
Author(s):  
Zhaoyan Lin ◽  
Zixiang Lin ◽  
Ying Zhao ◽  
Nan Cheng ◽  
Di Zhang ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Mitochondrial Pathway ◽  
Clinical Treatment ◽  
Gold Complex ◽  
Intact Female ◽  
Molecule Inhibitor ◽  
Mitochondrial Signaling ◽  
Tumor Agent

Canine breast cancer (CBC) is the most common spontaneous tumor in intact female dogs, especially in developing countries. The effective anti-tumor agents or therapies for the clinical treatment of CBC are still in need. Auranofin (AF) is a gold complex that has been attested by FDA for treating human rheumatism, which has been found as a great anti-tumor agent in recent years. ICG-001 is a small molecule inhibitor of Wnt/β-catenin pathway. In the present study, we demonstrated that a combination of AF and ICG-001 could synergistically suppress the proliferation of CBC in vitro and in vivo. Moreover, the synergistical effect was related with apoptosis caused by mitochondrial damage and ROS production. In conclusion, combination of AF and ICG-001 could synergistically suppress the growth of CBC in vitro and in vivo by leading apoptosis via mitochondrial signaling pathway and might provide a novel potential choice for the clinical treatment of CBC.

scholarly journals New Multiscale Characterization Methodology for Effective Determination of Isolation–Structure–Function Relationship of Extracellular Vesicles

2021 ◽  
Vol 9 ◽  
Author(s):  
Thanh Huyen Phan ◽  
Shiva Kamini Divakarla ◽  
Jia Hao Yeo ◽  
Qingyu Lei ◽  
Priyanka Tharkar ◽  
...  
Keyword(s):  
Extracellular Vesicles ◽  
Biological Effects ◽  
Dry Mass ◽  
Experimental Methodology ◽  
Wide Range ◽  
Isolation Methods ◽  
Function Relationship ◽  
Relationship Of

Extracellular vesicles (EVs) have been lauded as next-generation medicines, but very few EV-based therapeutics have progressed to clinical use. Limited clinical translation is largely due to technical barriers that hamper our ability to mass produce EVs, i.e., to isolate, purify, and characterize them effectively. Technical limitations in comprehensive characterization of EVs lead to unpredicted biological effects of EVs. Here, using a range of optical and non-optical techniques, we showed that the differences in molecular composition of EVs isolated using two isolation methods correlated with the differences in their biological function. Our results demonstrated that the isolation method determines the composition of isolated EVs at single and sub-population levels. Besides the composition, we measured for the first time the dry mass and predicted sedimentation of EVs. These parameters were likely to contribute to the biological and functional effects of EVs on single cell and cell cultures. We anticipate that our new multiscale characterization approach, which goes beyond traditional experimental methodology, will support fundamental understanding of EVs as well as elucidate the functional effects of EVs in in vitro and in vivo studies. Our findings and methodology will be pivotal for developing optimal isolation methods and establishing EVs as mainstream therapeutics and diagnostics. This innovative approach is applicable to a wide range of sectors including biopharma and biotechnology as well as to regulatory agencies.

Melatonin modifies tumor hypoxia and metabolism by inhibiting HIF-1α and energy metabolic pathway in the in vitro and in vivo models of breast cancer

2019 ◽  
Vol 2 (4) ◽  
pp. 83-98 ◽  
Author(s):  
André De Lima Mota ◽  
Bruna Vitorasso Jardim-Perassi ◽  
Tialfi Bergamin De Castro ◽  
Jucimara Colombo ◽  
Nathália Martins Sonehara ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Glucose Metabolism ◽  
Tumor Growth ◽  
Tumor Cells ◽  
Carbonic Anhydrases ◽  
In Vivo Models ◽  
Ca Ix ◽  
Gene And Protein Expression

Breast cancer is the most common cancer among women and has a high mortality rate. Adverse conditions in the tumor microenvironment, such as hypoxia and acidosis, may exert selective pressure on the tumor, selecting subpopulations of tumor cells with advantages for survival in this environment. In this context, therapeutic agents that can modify these conditions, and consequently the intratumoral heterogeneity need to be explored. Melatonin, in addition to its physiological effects, exhibits important anti-tumor actions which may associate with modification of hypoxia and Warburg effect. In this study, we have evaluated the action of melatonin on tumor growth and tumor metabolism by different markers of hypoxia and glucose metabolism (HIF-1α, glucose transporters GLUT1 and GLUT3 and carbonic anhydrases CA-IX and CA-XII) in triple negative breast cancer model. In an in vitro study, gene and protein expressions of these markers were evaluated by quantitative real-time PCR and immunocytochemistry, respectively. The effects of melatonin were also tested in a MDA-MB-231 xenograft animal model. Results showed that melatonin treatment reduced the viability of MDA-MB-231 cells and tumor growth in Balb/c nude mice (p <0.05). The treatment significantly decreased HIF-1α gene and protein expression concomitantly with the expression of GLUT1, GLUT3, CA-IX and CA-XII (p <0.05). These results strongly suggest that melatonin down-regulates HIF-1α expression and regulates glucose metabolism in breast tumor cells, therefore, controlling hypoxia and tumor progression. 

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