scholarly journals Rare Trafficking CFTR Mutations Involve Distinct Cellular Retention Machineries and Require Different Rescuing Strategies

2021 ◽  
Vol 23 (1) ◽  
pp. 24
Author(s):  
Sofia S. Ramalho ◽  
Iris A. L. Silva ◽  
Margarida D. Amaral ◽  
Carlos M. Farinha
Keyword(s):  
Cystic Fibrosis ◽  
Drug Discovery ◽  
Cell Lines ◽  
Class Ii ◽  
Molecular Defects ◽  
Knock Down ◽  
Intestinal Organoids ◽  
Cftr Mutations ◽  
Cellular Machinery

Most of the ~2100 CFTR variants so far reported are very rare and still uncharacterized regarding their cystic fibrosis (CF) disease liability. Since some may respond to currently approved modulators, characterizing their defect and response to these drugs is essential. Here we aimed characterizing the defect associated with four rare missense (likely Class II) CFTR variants and assess their rescue by corrector drugs. We produced CFBE cell lines stably expressing CFTR with W57G, R560S, H1079P and Q1100P, assessed their effect upon CFTR expression and maturation and their rescue by VX-661/VX-445 correctors. Results were validated by forskolin-induced swelling assay (FIS) using intestinal organoids from individuals bearing these variants. Finally, knock-down (KD) of genes previously shown to rescue F508del-CFTR was assessed on these mutants. Results show that all the variants preclude the production of mature CFTR, confirming them as Class II mutations. None of the variants responded to VX-661 but the combination rescued H1079P- and Q1100P-CFTR. The KD of factors that correct F508del-CFTR retention only marginally rescued R560S- and H1079P-CFTR. Overall, data evidence that Class II mutations induce distinct molecular defects that are neither rescued by the same corrector compounds nor recognized by the same cellular machinery, thus requiring personalized drug discovery initiatives.

scholarly journals Nanomolar-potency ‘co-potentiator’ therapy for cystic fibrosis caused by a defined subset of minimal function CFTR mutants

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Puay-Wah Phuan ◽  
Joseph-Anthony Tan ◽  
Amber A. Rivera ◽  
Lorna Zlock ◽  
Dennis W. Nielson ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Class Ii ◽  
Bronchial Epithelial Cell ◽  
Therapeutic Benefit ◽  
Initial Structure ◽  
Transmembrane Conductance Regulator ◽  
Loss Of Function ◽  
Nonsense Mutations ◽  
Minimal Function ◽  
Cftr Mutations

AbstractAvailable CFTR modulators provide no therapeutic benefit for cystic fibrosis (CF) caused by many loss-of-function mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel, including N1303K. We previously introduced the concept of ‘co-potentiators’ (combination-potentiators) to rescue CFTR function in some minimal function CFTR mutants. Herein, a screen of ~120,000 drug-like synthetic small molecules identified active co-potentiators of pyrazoloquinoline, piperidine-pyridoindole, tetrahydroquinoline and phenylazepine classes, with EC50 down to ~300 nM following initial structure-activity studies. Increased CFTR chloride conductance by up to 8-fold was observed when a co-potentiator (termed ‘Class II potentiator’) was used with a classical potentiator (‘Class I potentiator’) such as VX-770 or GLPG1837. To investigate the range of CFTR mutations benefitted by co-potentiators, 14 CF-associated CFTR mutations were studied in transfected cell models. Co-potentiator efficacy was found for CFTR missense, deletion and nonsense mutations in nucleotide binding domain-2 (NBD2), including W1282X, N1303K, c.3700A > G and Q1313X (with corrector for some mutations). In contrast, CFTR mutations G85E, R334W, R347P, V520F, R560T, A561E, M1101K and R1162X showed no co-potentiator activity, even with corrector. Co-potentiator efficacy was confirmed in primary human bronchial epithelial cell cultures generated from a N1303K homozygous CF subject. The Class II potentiators identified here may have clinical benefit for CF caused by mutations in the NBD2 domain of CFTR.

Functional tests for assessment of residual CFTR channel activity and personalized selection of efficacious CFTR-modulators for cystic fibrosis patients with ‘mild’ and ‘severe’ genetic variants

2021 ◽  
Vol 31 (2) ◽  
pp. 167-177
Author(s):  
E. L. Amelina ◽  
A. S. Efremova ◽  
Yu. L. Melyanovskaya ◽  
N. V. Bulatenko ◽  
T. B. Bukharova ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Clinical Data ◽  
Genetic Variant ◽  
Functional Tests ◽  
Channel Activity ◽  
Intestinal Organoids ◽  
Cftr Mutations ◽  
Rectal Biopsies ◽  
Cftr Modulators

Intestinal current measurement (ICM) and forskolin-induced swelling (FIS) assay in human intestinal organoids from rectal biopsies of cystic fibrosis (CF) patients are the new functional tests for assessment of CFTR channel activity that are widely used in the leading laboratories worldwide for scientific and clinical studies.The aim of the study was to assess the use of the new functional tests in adult CF patients with identified N1303K and R334W CFTR gene variants.Methods. Rectal suction biopsies were obtained from the two CF patients aged 36 and 27 years with N1303K/3821delT and R334W/F508del CFTR mutations, respectively. Results of the ICM and FIS assay in intestinal organoids were compared to the clinical data.Results. ICM has demonstrated that R334W is a ‘mild’ genetic variant with high residual CFTR channel activity. At the same time, N1303K is a ‘severe’ genetic variant and leads to a severe loss of CFTR channel function. These findings correlate with the clinical data. CFTR modulators compensate for the reduced activity of the R334W CFTR variant, as shown by the FIS assay. But there was a limited response of the forskolin-stimulated organoids to VX-770 potentiator and VX-809 corrector in the cells with N1303K genetic variant.Conclusion. ICM and FIS assay in human intestinal organoids are reliable methods for quantification of CFTR channel activity. They can also predict the efficacy of the targeted therapy in CF patients in vivo.

Novel Conjugated Quinazolinone-Based Hydroxamic Acids: Design, Synthesis and Biological Evaluation

2020 ◽  
Vol 16 ◽  
Author(s):  
Tran Khac Vu ◽  
Nguyen Thi Thanh ◽  
Nguyen Van Minh ◽  
Nguyen Huong Linh ◽  
Nguyen Thi Phương Thao ◽  
...  
Keyword(s):  
Drug Discovery ◽  
Cell Lines ◽  
Cancer Cell ◽  
Hdac Inhibitors ◽  
Cancer Cell Lines ◽  
Hydroxamic Acids ◽  
Biological Evaluation ◽  
Hdac Inhibition ◽  
Ic50 Value ◽  
Mcf 7

Background: Target-based approach to drug discovery currently attracts a great deal of interest from medicinal chemists in anticancer drug discovery and development. Histone deacetylase (HDAC) inhibitors represent an extensive class of targeted anti-cancer agents. Among the most explored structure moieties, hydroxybenzamides and hydroxypropenamides have been demonstrated to have potential HDAC inhibitory effects. Several compounds of these structural classes have been approved for clinical uses to treat different types of cancer, such as vorinostat and belinostat. Aims: This study aims at developing novel HDAC inhibitors bearing conjugated quinazolinone scaffolds with potential cytotoxicity against different cancer cell lines. Method: A series of novel N-hydroxyheptanamides incorporating conjugated 6-hydroxy-2 methylquinazolin-4(3H)- ones (15a-l) was designed, synthesized and evaluated for HDAC inhibitory potency as well as cytotoxicity against three human cancer cell lines, including HepG-2, MCF-7 and SKLu-1. Molecular simulations were finally performed to gain more insight into the structure-activity. relationships. Results: It was found that among novel conjugated quinazolinone-based hydroxamic acids synthesized, compounds 15a, 15c and 15f were the most potent, both in terms of HDAC inhibition and cytotoxicity. Especially, compound 15f displayed up to nearly 4-fold more potent than SAHA (vorinostat) in terms of cytotoxicity against MCF-7 cell line with IC50 value of 1.86 µM, and HDAC inhibition with IC50 value of 6.36 µM. Docking experiments on HDAC2 isozyme showed that these compounds bound to HDAC2 with binding affinities ranging from -10.08 to -14.93 kcal/mol compared to SAHA (-15.84 kcal/mol). It was also found in this research that most of the target compounds seemed to be more cytotoxic toward SKLu-1than MCF-7 and HepG-2. Conclusion: The resesrch results suggest that some hydroxamic acids could emerge for further evaluation and the results are well served as basics for further design of more potent HDAC inhibitors and antitumor agents.

scholarly journals Sirtuin 2 in Endometrial Cancer: A Potential Regulator for Cell Proliferation, Apoptosis and RAS/ERK Pathway

2020 ◽  
Vol 19 ◽  
pp. 153303382098078
Author(s):  
Yanjuan Guo ◽  
Nannan Zhao ◽  
Jianli Zhou ◽  
Jianxin Dong ◽  
Xing Wang
Keyword(s):  
Cell Proliferation ◽  
Endometrial Cancer ◽  
Western Blot ◽  
Cell Line ◽  
Cell Lines ◽  
Erk Pathway ◽  
Uterine Epithelial Cell ◽  
Knock Down ◽  
Ishikawa Cells ◽  
And Control

Objective: The present study aimed to explore the function of sirtuin 2 (SIRT2) on cell proliferation, apoptosis, rat sarcoma virus (RAS)/ extracellular signal-regulated kinase (ERK) pathway in endometrial cancer (EC). Methods: SIRT2 expression in human EC cell lines and human endometrial (uterine) epithelial cell (HEEC) line was assessed by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot. SIRT2 knock-down and control knock-down plasmids were transfected into HEC1A cells, respectively; SIRT2 overexpression and control overexpression plasmids were transfected into Ishikawa cells, respectively. After transfection, SIRT2, HRas proto-oncogene, GTPase (HRAS) expressions were evaluated by RT-qPCR and western blot. ERK and phosphorylated ERK (pERK) expressions were evaluated by western blot. Meanwhile, cell proliferation and cell apoptosis were measured. Results: Compared to normal HEEC cell line, SIRT2 mRNA and protein expressions were increased in most human EC cell lines (including HEC1A, RL952 and AN3CA), while were similar in Ishikawa cell line. In HEC1A cells, SIRT2 knock-down decreased cell proliferation but increased apoptosis. In Ishikawa cells, SIRT2 overexpression induced cell proliferation but inhibited apoptosis. For RAS/ERK pathway, SIRT2 knock-down reduced HRAS and inactivated pERK in HEC1A cells, whereas SIRT2 overexpression increased HRAS and activated pERK in Ishikawa cells, suggesting that SIRT2 was implicated in the regulation of RAS/ERK pathway in EC cells. Conclusion: SIRT2 contributes to the EC tumorigenesis, which appears as a potential therapeutic target.

scholarly journals Human Immunodeficiency Virus Type 1 Replication in the Absence of Integrase-Mediated DNA Recombination: Definition of Permissive and Nonpermissive T-Cell Lines

2001 ◽  
Vol 75 (17) ◽  
pp. 7944-7955 ◽  
Author(s):  
Noriko Nakajima ◽  
Richard Lu ◽  
Alan Engelman
Keyword(s):  
Human Immunodeficiency Virus ◽  
Cell Lines ◽  
Dna Recombination ◽  
Cell Types ◽  
Class Ii ◽  
Class I ◽  
Immunodeficiency Virus ◽  
T Cell Lines ◽  
Hiv 1

ABSTRACT Functional retroviral integrase protein is thought to be essential for productive viral replication. Yet, previous studies differed on the extent to which integrase mutant viruses expressed human immunodeficiency virus type 1 (HIV-1) genes from unintegrated DNA. Although one reason for this difference was that class II integrase mutations pleiotropically affected the viral life cycle, another reason apparently depended on the identity of the infected cell. Here, we analyzed integrase mutant viral infectivities in a variety of cell types. Single-round infectivity of class I integration-specific mutant HIV-1 ranged from <0.03 to 0.3% of that of the wild type (WT) across four different T-cell lines. Based on this approximately 10-fold influence of cell type on mutant gene expression, we examined class I and class II mutant replication kinetics in seven different cell lines and two primary cell types. Unexpectedly, some cell lines supported productive class I mutant viral replication under conditions that restricted class II mutant growth. Cells were defined as permissive, semipermissive, or nonpermissive based on their ability to support the continual passage of class I integration-defective HIV-1. Mutant infectivity in semipermissive and permissive cells as quantified by 50% tissue culture infectious doses, however, was only 0.0006 to 0.005% of that of WT. Since the frequencies of mutant DNA recombination in these lines ranged from 0.023 to <0.093% of the WT, we conclude that productive replication in the absence of integrase function most likely required the illegitimate integration of HIV-1 into host chromosomes by cellular DNA recombination enzymes.

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