scholarly journals Novel FGFR1 Variants Are Associated with Congenital Scoliosis

Genes ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 1126
Author(s):  
Shengru Wang ◽  
Xiran Chai ◽  
Zihui Yan ◽  
Sen Zhao ◽  
Yang Yang ◽  
...  
Keyword(s):  
Protein Function ◽  
Hypogonadotropic Hypogonadism ◽  
Congenital Scoliosis ◽  
Wild Type ◽  
Conservation Analysis ◽  
Gene Assay ◽  
Protein Expressions ◽  
Patient Series ◽  
Reduced Activity

FGFR1 encodes a transmembrane cytokine receptor, which is involved in the early development of the human embryo and plays an important role in gastrulation, organ specification and patterning of various tissues. Pathogenic FGFR1 variants have been associated with Kallmann syndrome and hypogonadotropic hypogonadism. In our congenital scoliosis (CS) patient series of 424 sporadic CS patients under the framework of the Deciphering disorders Involving Scoliosis and COmorbidities (DISCO) study, we identified four unrelated patients harboring FGFR1 variants, including one frameshift and three missense variants. These variants were predicted to be deleterious by in silico prediction and conservation analysis. Signaling activities and expression levels of the mutated protein were evaluated in vitro and compared to that of the wild type (WT) FGFR1. As a result, the overall protein expressions of c.2334dupC, c.2339T>C and c.1261A>G were reduced to 43.9%, 63.4% and 77.4%, respectively. By the reporter gene assay, we observed significantly reduced activity for c.2334dupC, c.2339T>C and c.1261A>G, indicating the diminished FGFR1 signaling pathway. In conclusion, FGFR1 variants identified in our patients led to only mild disruption to protein function, caused milder skeletal and cardiac phenotypes than those reported previously.

scholarly journals Novel Salmonella enterica Serovar Typhimurium Protein That Is Indispensable for Virulence and Intracellular Replication

2001 ◽  
Vol 69 (12) ◽  
pp. 7413-7418 ◽  
Author(s):  
Tahar van der Straaten ◽  
Angela van Diepen ◽  
Kitty Kwappenberg ◽  
Sjaak van Voorden ◽  
Kees Franken ◽  
...  
Keyword(s):  
Amino Acid ◽  
Protein Function ◽  
Salmonella Enterica ◽  
Host Cells ◽  
Wild Type ◽  
Intracellular Replication ◽  
Oxygen Intermediates ◽  
Serovar Typhimurium

ABSTRACT Upon contact with host cells, the intracellular pathogenSalmonella enterica serovar Typhimurium promotes its uptake, targeting, and survival in intracellular niches. In this process, the bacterium evades the microbicidal effector mechanisms of the macrophage, including oxygen intermediates. This study reports the phenotypic and genotypic characterization of an S. enterica serovar Typhimurium mutant that is hypersusceptible to superoxide. The susceptible phenotype is due to a MudJ insertion-inactivation of a previously undescribedSalmonella gene designated sspJ that is located between 54.4 and 64 min of the Salmonellachromosome and encodes a 392-amino-acid protein. In vivo, upon intraperitoneal injection of 104 to 107bacteria in C3H/HeN and 101 to 104 bacteria in BALB/c mice, the mutant strain was less virulent than the wild type. Consistent with this finding, during the first hour after ingestion by macrophage-like J774 and RAW264.7 cells in vitro, the intracellular killing of the strain carrying sspJ::MudJ is enhanced fivefold over that of wild-type microorganisms. Wild-type salmonellae displayed significant intracellular replication during the first 24 h after uptake, but sspJ::MudJ mutants failed to do so. This phenotype could be restored to that of the wild type by sspJ complementation. The SspJ protein is found in the cytoplasmic membrane and periplasmic space. Amino acid sequence homology analysis did reveal a leader sequence and putative pyrroloquinoline quinone-binding domains, but no putative protein function. We excluded the possibility that SspJ is a scavenger of superoxide or has superoxide dismutase activity.

scholarly journals The Protein Translocation Defect of MCT8L291R Is Rescued by Sodium Phenylbutyrate

2020 ◽  
Vol 9 (5) ◽  
pp. 269-280
Author(s):  
Doreen Braun ◽  
Ulrich Schweizer
Keyword(s):  
Plasma Membrane ◽  
Protein Function ◽  
Monocarboxylate Transporter ◽  
Cell Surface Expression ◽  
Mrna Levels ◽  
Wild Type ◽  
Chemical Chaperone ◽  
Mct8 Deficiency ◽  
Sodium Phenylbutyrate

Introduction: The monocarboxylate transporter 8 (MCT8; SLC16A2) is a specific transporter for thyroid hormones. MCT8 deficiency, formerly known as the Allan-Herndon-Dudley syndrome, is a rare genetic disease that leads to neurological impairments and muscle weakness. Current experimental treatment options rely on thyromimetic agonists that do not depend on MCT8 for cellular uptake. Another approach comes from studies with the chemical chaperone sodium phenylbutyrate (NaPB), which was able to stabilize MCT8 mutants having protein folding defects in vitro. In addition, NaPB is known as a compound that assists with plasma membrane translocation. Objective: The pathogenic MCT8L291R leads to the same severe neurological impairments found for other MCT8-deficient patients but, unexpectedly, lacks alterations in plasma 3,3′,5-triiodothyronine (T3) levels. Here we tried to unravel the underlying mechanism of MCT8 deficiency and tested whether the pathogenic MCT8L291R mutant responds to NaPB treatment. Therefore, we overexpressed the mutant in Madin-Darby canine kidney cells in the human choriocarcinoma cell line JEG1 and in COS7 cells of African green monkey origin. Results: In our recent study we describe that the MCT8L291R mutation most likely leads to a translocation defect. The pathogenic mutant is not located at the plasma membrane, but shows overlapping expression with a marker protein of the lysosome. Mutation of the corresponding amino acid in murine Mct8 (Mct8L223R) displays a similar effect on cell surface expression and transport function as seen before for MCT8L291R. NaPB was able to correct the translocation defect of MCT8L291R/Mct8L223R and restored protein function by increasing T3 transport activity. Furthermore, we detected enhanced mRNA levels of wild-type and mutant MCT8/Mct8 after NaPB treatment. The increase in mRNA levels could be an explanation for the positive effect on protein expression and function detected for wild-type MCT8. Conclusion: NaPB is not only suitable for the treatment of mutations leading to misfolding and protein degradation, but also for a mutant wrongly sorted inside a cell which is otherwise functional.

scholarly journals Mutational analysis of the necdin gene in patients with congenital isolated hypogonadotropic hypogonadism

2011 ◽  
Vol 165 (1) ◽  
pp. 145-150 ◽  
Author(s):  
Daiane Beneduzzi ◽  
Anita K Iyer ◽  
Ericka Barbosa Trarbach ◽  
Acacio P Silveira-Neto ◽  
Letícia G Silveira ◽  
...  
Keyword(s):  
Mutational Analysis ◽  
Hypogonadotropic Hypogonadism ◽  
Kallmann Syndrome ◽  
Luciferase Reporter ◽  
Causative Role ◽  
Wild Type ◽  
Protein Activity ◽  
Functional Studies ◽  
Significant Impairment

ContextNecdin activates GNRH gene expression and is fundamental for the development, migration, and axonal extension of murine GNRH neurons. In humans, necdin plays a potential role in the hypogonadotropic hypogonadism phenotype in patients with Prader–Willi syndrome.AimTo investigate necdin gene (NDN) variants in patients with isolated hypogonadotropic hypogonadism (IHH).Patients and methodsWe studied 160 Brazilian patients with IHH, which includes 92 with Kallmann syndrome and 68 with normosmic IHH. Genomic DNA was extracted and the single NDN exon was amplified and sequenced. To measure GNRH transcriptional activity, luciferase reporter plasmids containing GNRH regulatory regions were transiently transfected into GT1-7 cells in the presence and absence of overexpressed wild-type or mutant necdin.ResultsA heterozygous variant of necdin, p.V318A, was identified in a 23-year-old male with Kallmann syndrome. The p.V318A was also present in affected aunt and his father and was absent in 100 Brazilian control subjects. Previous FGFR1 gene analysis revealed a missense mutation (p.P366L) in this family. Functional studies revealed a minor difference in the activation of GNRH transcription by mutant protein compared with wild type in that a significant impairment of the necdin protein activity threshold was observed.ConclusionA rare variant of necdin (p.V318A) was described in a family with Kallmann syndrome associated with a FGFR1 mutation. Familial segregation and in vitro analysis suggested that this non-synonymous variant did not have a direct causative role in the hypogonadism phenotype. NDN mutations are not a frequent cause of congenital IHH.

Μελέτη της επίδρασης της ελευρωπαΐνης στην ομοιοστασία των λιπιδίων

2017 ◽  
Author(s):  
Φωτεινή Μάλλιου
Keyword(s):  
Reporter Gene ◽  
In Silico ◽  
Reporter Gene Assay ◽  
Luciferase Reporter ◽  
Wild Type ◽  
Luciferase Reporter Gene ◽  
Luciferase Reporter Gene Assay ◽  
Gene Assay

Η Ελευρωπαΐνη, το κύριο πολυφαινολικό συστατικό της ελιάς, παρουσιάζει αντιοξειδωτικές και υπολιπιδαιμικές ιδιότητες. Ο ενεργοποιημένος υποδοχέας επαγωγής του πολλαπλασιασμού των υπεροξεισωμάτων τύπου α (PPARα), διαδραματίζει καίριο ρόλο στον έλεγχο του μεταβολισμού των λιπιδίων και στην ενεργειακή ομοιαστασία του κυττάρου. Η συγκεκριμένη έρευνα εστιάζει στους μηχανισμούς της υπολιπιδαιμικής δράσης της Ελευρωπαΐνης με έμφαση στο ρόλο της Ελευρωπαΐνης στην ενεργοποίηση του PPARα. Για τον σκοπό αυτό, έγινε αξιολόγηση in silico της ικανότητας της Ελευρωπαΐνης να προσδένεται στον PPARα. Θεωρητικά μοντέλα πρόσδεσης στην κρυσταλλική δομή του PPARα με τη χρήση Μοριακής Προσομοίωσης Πρόσδεσης, επιβεβαιώνουν την υπόθεσή μας ότι η Ελευρωπαΐνη είναι αγωνιστής του PPARα. Επιπλέον, διερευνήθηκε in vitro με το Luciferase reporter gene assay η ικανότητα της Ελευρωπαΐνης να προσδένεται στον υποδοχέα PPARα και να τον ενεργοποιεί. Τα αποτελέσματα από την in silico και την in vitro μελέτη δείχνουν σαφώς ότι η ελευρωπαΐνη ενεργοποιεί τον PPARα. Στη συνέχεια έγινε in vivo διερεύνηση της ενεργοποίησης του PPARα από την Ελευρωπαΐνη και αξιολόγηση της επίδρασής της στο λιπιδαιμικό προφίλ των πειραματόζωων. Αγωγή αρσενικών μυών άγριου τύπου (SV129 Wild Type) με Ελευρωπαΐνη σε δοσολογία 100mg/kg, p.o, τα οποία ακολούθησαν τυπική δίαιτα για τρωκτικά, για 6 εβδομάδες, είχε ως αποτέλεσμα επαγωγή του Pparα και των γονιδίων-στόχων του στο ήπαρ, πιθανώς μέσω ενεργοποίησης του PI3K/AKT/p70S6K σηματοδοτικού μονοπατιού. Αυτή η επίδραση της Ελευρωπαΐνης φαίνεται να σχετίζεται άμεσα με σημαντική μείωση των επιπέδων των TGs του ορού και της ολικής χοληστερόλης, γιατί η Ελευρωπαΐνη δεν είχε καμία επίδραση σε αυτούς τους λιπιδαιμικούς δείκτες σε διαγονιδιακούς Pparα null μύες. Στην κατεύθυνση της διερεύνησης της επίδρασης της Ελευρωπαΐνης σε ηπατικούς παράγοντες και σε παράγοντες, που εκφράζονται στο λευκό λιπώδη, κρίσιμους για την ομοιοστασία των Τριγλυκεριδίων, διαπιστώθηκαν τα ακόλουθα: 1) Ενεργοποίηση της ορμονο-ευαίσθητης λιπάσης (HSL) στο λευκό λιπώδη ιστό (W.A.T.) των άγριου τύπου μυών, 2) επαγωγή ποικίλλων ηπατικών παραγόντων, που συμμετέχουν στη σύνθεση, τη μεταφορά, τον μεταβολισμό και την απέκκριση των τριγλυκεριδίων. Αυτή η ενεργοποίηση της HSL στον W.A.T. και των ηπατικών παραγόντων, που συμμετέχουν στην ομοιοστασία των λιπιδίων, είναι πιθανόν να ενισχύει την επαγόμενη από την Ελευρωπαΐνη μείωση των επιπέδων των τριγλυκεριδίων και της χοληστερόλης στον ορό. Συνοψίζοντας, φαίνεται ότι η Ελευρωπαΐνη μειώνει τα τριγλυκερίδια και την ολική χοληστερόλη του ορού σε μύες μέσω ενεργοποίησης του PPARα. Τα δεδομένα αυτής της μελέτης δείχνουν επίσης, ότι στην υπολιπιδαιμική δράση της Ελευρωπαΐνης συμμετέχει και η ενεργοποίηση της HSL στο λευκό λιπώδη ιστό καθώς και η επαγωγή ηπατικών γονιδίων, που διαδραματίζουν βασικό ρόλο την ομοιοστασία των τριγλυκεριδίων, δηλαδή τη σύνθεση, την μεταφορά, τον μεταβολισμό και την κάθαρσή τους. Συμπερασματικά, η μελέτη έδειξε τις υπολιπιδαιμικές δυνατότητες της Ελευρωπαΐνης σε μύες και αποσαφήνισε σε σημαντικό βαθμό τους μηχανισμούς της υπολιπιδαιμικής δράσης της, φωτίζοντας κυρίως τον ρόλο του PPARα. Επειδή η διατήρηση της ομοιοστασίας των λιπιδίων είναι μια πολύπλοκη διαδικασία, που ρυθμίζεται από πολλούς παράγοντες, πιστεύουμε ότι πιθανώς εμπλέκονται και άλλοι μηχανισμοί στην δράση της Ελευρωπαΐνης, η διερεύνηση των οποίων είναι αντικείμενο μελλοντικών μελετών.

scholarly journals Mutations of the KISS1 Gene in Disorders of Puberty

2010 ◽  
Vol 95 (5) ◽  
pp. 2276-2280 ◽  
Author(s):  
L. G. Silveira ◽  
S. D. Noel ◽  
A. P. Silveira-Neto ◽  
A. P. Abreu ◽  
V. N. Brito ◽  
...  
Keyword(s):  
Human Serum ◽  
Precocious Puberty ◽  
Inositol Phosphate ◽  
Pubertal Development ◽  
Hypogonadotropic Hypogonadism ◽  
Central Precocious Puberty ◽  
Control Group ◽  
Missense Mutations ◽  
Wild Type

Abstract Context: Kisspeptin, encoded by the KISS1 gene, is a key stimulatory factor of GnRH secretion and puberty onset. Inactivating mutations of its receptor (KISS1R) cause isolated hypogonadotropic hypogonadism (IHH). A unique KISS1R-activating mutation was described in central precocious puberty (CPP). Objective: Our objective was to investigate KISS1 mutations in patients with idiopathic CPP and normosmic IHH. Patients: Eighty-three children with CPP (77 girls) and 61 patients with IHH (40 men) were studied. The control group consisted of 200 individuals with normal pubertal development. Methods: The promoter region and the three exons of KISS1 were amplified and sequenced. Cells expressing KISS1R were stimulated with synthetic human wild-type or mutant kisspeptin-54 (kp54), and inositol phosphate accumulation was measured. In a second set of experiments, kp54 was preincubated in human serum before stimulation of the cells. Results: Two novel KISS1 missense mutations, p.P74S and p.H90D, were identified in three unrelated children with idiopathic CPP. Both mutations were absent in 400 control alleles. The p.P74S mutation was identified in the heterozygous state in a boy who developed CPP at 1 yr of age. The p.H90D mutation was identified in the homozygous state in two unrelated girls with CPP. In vitro studies revealed that the capacity of the P74S and H90D mutants to stimulate IP production was similar to the wild type. After preincubation of wild-type and mutant kp54 in human serum, the capacity to stimulate signal transduction was significantly greater for P74S compared with the wild type, suggesting that the p.P74S variant is more stable. Only polymorphisms were found in the IHH group. Conclusion: Two KISS1 mutations were identified in unrelated patients with idiopathic CPP. The p.P74S variant was associated with higher kisspeptin resistance to degradation in comparison with the wild type, suggesting a role for this mutation in the precocious puberty phenotype.

scholarly journals Reduced Activity of Mutant Calcium-Dependent Protein Kinase 1 Is Compensated in Plasmodium falciparum through the Action of Protein Kinase G

mBio ◽  
2016 ◽  
Vol 7 (6) ◽  
Author(s):  
Abhisheka Bansal ◽  
Kayode K. Ojo ◽  
Jianbing Mu ◽  
Dustin J. Maly ◽  
Wesley C. Van Voorhis ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Protein Kinase ◽  
Protein Kinase G ◽  
Wild Type ◽  
Dependent Protein Kinase ◽  
Calcium Dependent ◽  
Dependent Protein ◽  
Reduced Activity ◽  
Calcium Dependent Protein Kinase

ABSTRACT We used a sensitization approach that involves replacement of the gatekeeper residue in a protein kinase with one with a different side chain. The activity of the enzyme with a bulky gatekeeper residue, such as methionine, cannot be inhibited using bumped kinase inhibitors (BKIs). Here, we have used this approach to study Plasmodium falciparum calcium-dependent protein kinase 1 ( Pf CDPK1). The methionine gatekeeper substitution, T145M, although it led to a 47% reduction in transphosphorylation, was successfully introduced into the CDPK1 locus using clustered regularly interspaced short palindromic repeat (CRISPR)/Cas9. As methionine is a bulky residue, BKI 1294 had a 10-fold-greater effect in vitro on the wild-type enzyme than on the methionine mutant. However, in contrast to in vitro data with recombinant enzymes, BKI 1294 had a slightly greater inhibition of the growth of CDPK1 T145M parasites than the wild type. Moreover, the CDPK1 T145M parasites were more sensitive to the action of compound 2 (C2), a specific inhibitor of protein kinase G (PKG). These results suggest that a reduction in the activity of CDPK1 due to methionine substitution at the gatekeeper position is compensated through the direct action of PKG or of another kinase under the regulation of PKG. The transcript levels of CDPK5 and CDPK6 were significantly upregulated in the CDPK1 T145M parasites. The increase in CDPK6 or some other kinase may compensate for decrease in CDPK1 activity during invasion. This study suggests that targeting two kinases may be more effective in chemotherapy to treat malaria so as not to select for mutations in one of the enzymes. IMPORTANCE Protein kinases of Plasmodium falciparum are being actively pursued as drug targets to treat malaria. However, compensatory mechanisms may reverse the drug activity against a kinase. In this study, we show that replacement of the wild-type threonine gatekeeper residue with methionine reduces the transphosphorylation activity of CDPK1. Mutant parasites with methionine gatekeeper residue compensate the reduced activity of CDPK1 through the action of PKG possibly by upregulation of CDPK6 or some other kinase. This study highlights that targeting one enzyme may lead to changes in transcript expression of other kinases that compensate for its function and may select for mutants that are less dependent on the target enzyme activity. Thus, inhibiting two kinases is a better strategy to protect the antimalarial activity of each, similar to artemisinin combination therapy or malarone (atovaquone and proguanil).

scholarly journals Inhibition of TATA-Binding Protein Function by SAGA Subunits Spt3 and Spt8 at Gcn4-Activated Promoters

2000 ◽  
Vol 20 (2) ◽  
pp. 634-647 ◽  
Author(s):  
Rimma Belotserkovskaya ◽  
David E. Sterner ◽  
Min Deng ◽  
Michael H. Sayre ◽  
Paul M. Lieberman ◽  
...  
Keyword(s):  
Transcriptional Activation ◽  
Protein Function ◽  
Associated Factors ◽  
Transcriptional Start Site ◽  
Wild Type ◽  
Yeast Protein ◽  
Related Factors ◽  
Cell Extracts

ABSTRACT SAGA is a 1.8-MDa yeast protein complex that is composed of several distinct classes of transcription-related factors, including the adaptor/acetyltransferase Gcn5, Spt proteins, and a subset of TBP-associated factors. Our results indicate that mutations that completely disrupt SAGA (deletions of SPT7 orSPT20) strongly reduce transcriptional activation at theHIS3 and TRP3 genes and that Gcn5 is required for normal HIS3 transcriptional start site selection. Surprisingly, mutations in Spt proteins involved in the SAGA-TBP interaction (Spt3 and Spt8) cause derepression of HIS3 andTRP3 transcription in the uninduced state. Consistent with this finding, wild-type SAGA inhibits TBP binding to theHIS3 promoter in vitro, while SAGA lacking Spt3 or Spt8 is not inhibitory. We detected two distinct forms of SAGA in cell extracts and, strikingly, one lacks Spt8. Conditions that induceHIS3 and TRP3 transcription result in an altered balance between these complexes strongly in favor of the form without Spt8. These results suggest that the composition of SAGA may be dynamic in vivo and may be regulated through dissociable inhibitory subunits.

scholarly journals Selinexor Improves the Anti-Cancer Effect of Tucidinostat on TP53 Wild-type Breast Cancer

2021 ◽  
Author(s):  
Shengxi Xu ◽  
Yingfang Shi ◽  
Sen Li
Keyword(s):  
Breast Cancer ◽  
Cyclin D1 ◽  
Effective Strategy ◽  
Wild Type ◽  
Expression Levels ◽  
Anti Cancer ◽  
Protein Expressions ◽  
Proliferation And Invasion ◽  
Mcf 7

Abstract Background: Histone deacetylase (HDAC) is closely related to the occurrence and development of breast cancer (BC). Its inhibitor (HDACi) has been used to treat BC, while the efficacy of clinical trials was not reached expectations. HDACi combined with other drugs may be an effective strategy. This study explored the effect of HDACitucidinostat combined with selinexor, anexportin 1 (XPO1) inhibitor, on BC cellsin vitro. Methods: BC cell lines of MCF-7 (wt-TP53), MDA-MB-175 (wt-TP53), MDA-MB-134 (mut-TP53), T47D (mut-TP53) were cultured. The IC50 values of tucidinostat and selinexor on BC cells were calculated. The effects of tucidinostat and selinexor on proliferation, invasion and apoptosis of BC cells were observed accordingly. Western blotting was used to detect the protein expressions of p53, p21, Cyclin D1, Bcl-2 and Bax.Results:Compared with mut-TP53 BC, both tucidinostat and selinexor showed better inhibitory activitiesonwt-TP53 BC including MCF-7 and MDA-MB-175. Tucidinostat combined with selinexor significantly improved the effects of tucidinostat alone on the proliferation and invasion inhibitions and apoptosis promotionsof MCF-7 and MDA-MB-175 cells in vitro. It also significantly enhanced the effects of tucidinostat on up-regulating the expression levels of acetyl-p53, nuclear p53, total p53, p21 and Bax, and down-regulating the expression levels of Cyclin D1 and Bcl-2 in MCF-7 or MDA-MB-175 cells. Conclusion: Taken together, we believe that tucidinostat and selinexor are potentially effective drug combinations for the treatment of wt-TP53 BC, and the molecular mechanism may be throughenhancing the activity of p53 in the nucleus of BC cells to suppress proliferation and invasion and promote apoptosis of BC cells.

scholarly journals Requirement of Cysteines and Length of the Human Respiratory Syncytial Virus M2-1 Protein for Protein Function and Virus Viability

2001 ◽  
Vol 75 (23) ◽  
pp. 11328-11335 ◽  
Author(s):  
Roderick S. Tang ◽  
Nick Nguyen ◽  
Xing Cheng ◽  
Hong Jin
Keyword(s):  
Amino Acids ◽  
Respiratory Syncytial Virus ◽  
Protein Function ◽  
Rna Synthesis ◽  
Human Respiratory Syncytial Virus ◽  
Wild Type ◽  
C Terminus ◽  
Cotton Rats ◽  
Syncytial Virus

ABSTRACT The M2-1 protein of human respiratory syncytial virus (hRSV) promotes processive RNA synthesis and readthrough at RSV gene junctions. It contains four highly conserved cysteines, three of which are located in the Cys3-His1motif at the N terminus of M2-1. Each of the four cysteines, at positions 7, 15, 21, and 96, in the M2-1 protein of hRSV A2 strain was individually replaced by glycines. When tested in an RSV minigenome replicon system using β-galactosidase as a reporter gene, C7G, C15G, and C21G located in the Cys3-His1motif showed a significant reduction in processive RNA synthesis compared to wild-type (wt) M2-1. C96G, which lies outside the Cys3-His1 motif, was fully functional in supporting processive RNA synthesis in vitro. Each of these cysteine substitutions was introduced into an infectious antigenomic cDNA clone derived from hRSV A2 strain. Except for C96G, which resulted in a viable virus, no viruses were recovered with mutations in the Cys3-His1 motif. This indicates that the Cys3-His1 motif is critical for M2-1 function and for RSV replication. The functional requirement of the C terminus of the M2-1 protein was examined by engineering premature stop codons that caused truncations of 17, 46, or 67 amino acids from the C terminus. A deletion of 46 or 67 amino acids abolished the synthesis of full-length β-galactosidase mRNA and did not result in the recovery of viable viruses. However, a deletion of 17 amino acids from the C terminus of M2-1 reduced processive RNA synthesis in vitro and was well tolerated by RSV. Relocation of the M2-1 termination codon upstream of the M2-2 initiation codons did not significantly affect the expression of the M2-2 protein. Both rA2-Tr17 and rA2-C96G did not replicate as efficiently as wt rA2 in HEp-2 cells and was restricted in replication in the respiratory tracts of cotton rats.

Benzisothiazolone Derivatives Exhibit Cytotoxicity in Hodgkin’s Lymphoma Cells through NF-κB Inhibition and are Synergistic with Doxorubicin and Etoposide

2020 ◽  
Vol 20 (6) ◽  
pp. 715-723
Author(s):  
Natarajan Nandakumar ◽  
Pushparathinam Gopinath ◽  
Jacob Gopas ◽  
Kannoth M. Muraleedharan
Keyword(s):  
Synergistic Effect ◽  
Hodgkin’S Lymphoma ◽  
A549 Cells ◽  
Hodgkin's Lymphoma ◽  
Luciferase Reporter ◽  
Luciferase Reporter Gene ◽  
Lymphoma Cells ◽  
Nuclear Extracts ◽  
Gene Assay

Background: The authors investigated the NF-κB inhibitory role of three Benzisothiazolone (BIT) derivatives (1, 2 and 3) in Hodgkin’s Lymphoma cells (L428) which constitutively express activated NF-κB. All three compounds showed dose-dependent NF-κB inhibition (78.3, 70.7 and 34.6%) in the luciferase reporter gene assay and were found cytotoxic at IC50 values of 3.3μg/ml, 4.35μg/ml and 13.8μg/ml, respectively by the XTT assay. BIT 1and BIT 2 (but not BIT 3) suppressed both NF-κB subunits p50 and p65 in cytoplasmic and nuclear extracts in a concentration-dependent manner. Furthermore, BIT 1 showed a moderate synergistic effect with the standard chemotherapy drugs etoposide and doxorubicin, whereas BIT 2 and 3 showed a moderate additive effect to antagonistic effect. Cisplatin exhibited an antagonist effect on all the compounds tested under various concentrations, except in the case of 1.56μg/ml of BIT 3 with 0.156μg/ml of cisplatin. The compounds also inhibited the migration of adherent human lung adenocarcinoma cells (A549) in vitro. We conclude that especially BIT 1 and BIT 2 have in vitro anti-inflammatory and anti-cancer activities, which can be further investigated for future potential therapeutic use. Methods: Inspired by the electrophilic sulfur in Nuphar alkaloids, monomeric and dimeric benzisothiazolones were synthesized from dithiodibenzoic acid and their NF-κB inhibitory role was explored. NF-κB inhibition and cytotoxicity of the synthesized derivatives were studied using luciferase reporter gene assay and XTTassay. Immunocytochemistry studies were performed using L428 cells. Cell migration assay was conducted using the A549 cell line. L428 cells were used to conduct combination studies and the results were plotted using CompuSyn software. Results: Benzisothiazolone derivatives exhibited cytotoxicity in Hodgkin’s Lymphoma cells through NF-κB inhibition. Potent compounds showed suppression of both NF-κB subunits p50 and p65 in a concentrationdependent manner, both in cytoplasmic and nuclear extracts. Combination studies suggest that benzisothiazolone derivatives possess a synergistic effect with etoposide and doxorubicin. Furthermore, the compounds also inhibited the migration of A549 cells. Conclusion: Benzisothiazolones bearing one or two electrophilic sulfur atoms as part of the heterocyclic framework exhibited cytotoxicity in Hodgkin’s Lymphoma cells through NF-κB inhibition. In addition, these derivatives also exhibited a synergistic effect with etoposide and doxorubicin along with the ability to inhibit the migration of A549 cells. Our study suggests that BIT-based new chemical entities could lead to potential anticancer agents.

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