scholarly journals RNF13 Dileucine Motif Variants L311S and L312P Interfere with Endosomal Localization and AP-3 Complex Association

Cells ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 3063
Author(s):  
Valérie C. Cabana ◽  
Antoine Y. Bouchard ◽  
Audrey M. Sénécal ◽  
Kim Ghilarducci ◽  
Saïd Kourrich ◽  
...  
Keyword(s):  
Genetic Alterations ◽  
Wild Type ◽  
Cellular Mechanisms ◽  
Dileucine Motif ◽  
Epidermal Growth ◽  
Refractory Seizures ◽  
Temporal And Spatial ◽  
Endosomal Vesicles ◽  
Protein Variants ◽  
Severe Epilepsy

Developmental and epileptic encephalopathies (DEE) are rare and serious neurological disorders characterized by severe epilepsy with refractory seizures and a significant developmental delay. Recently, DEE73 was linked to genetic alterations of the RNF13 gene, which convert positions 311 or 312 in the RNF13 protein from leucine to serine or proline, respectively (L311S and L312P). Using a fluorescence microscopy approach to investigate the molecular and cellular mechanisms affected by RNF13 protein variants, the current study shows that wild-type RNF13 localizes extensively with endosomes and lysosomes, while L311S and L312P do not extensively colocalize with the lysosomal marker Lamp1. Our results show that RNF13 L311S and L312P proteins affect the size of endosomal vesicles along with the temporal and spatial progression of fluorescently labeled epidermal growth factor, but not transferrin, in the endolysosomal system. Furthermore, GST-pulldown and co-immunoprecipitation show that RNF13 variants disrupt association with AP-3 complex. Knockdown of AP-3 complex subunit AP3D1 alters the lysosomal localization of wild-type RNF13 and similarly affects the size of endosomal vesicles. Importantly, our study provides a first step toward understanding the cellular and molecular mechanism altered by DEE73-associated genetic variations of RNF13.

scholarly journals Genomic Profiling of Premenopausal HR+ and HER2– Metastatic Breast Cancer by Circulating Tumor DNA and Association of Genetic Alterations With Therapeutic Response to Endocrine Therapy and Ribociclib

2021 ◽  
pp. 1408-1420
Author(s):  
Aditya Bardia ◽  
Fei Su ◽  
Nadia Solovieff ◽  
Seock-Ah Im ◽  
Joohyuk Sohn ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Tyrosine Kinases ◽  
Growth Factor Receptor ◽  
Circulating Tumor Dna ◽  
Genetic Alterations ◽  
Wild Type ◽  
Hormone Receptor Positive ◽  
Epidermal Growth ◽  
Premenopausal Patients ◽  
Tumor Dna

PURPOSE This analysis evaluated the genomic landscape of premenopausal patients with hormone receptor–positive and human epidermal growth factor receptor 2–negative advanced breast cancer and the association of genetic alterations with response to ribociclib in the phase III MONALEESA-7 trial. METHODS Premenopausal patients were randomly assigned 1:1 to receive endocrine therapy plus ribociclib or placebo. Plasma collected at baseline was sequenced using targeted next-generation sequencing for approximately 600 relevant cancer genes. The association of circulating tumor DNA alterations with progression-free survival (PFS) was evaluated to identify biomarkers of response and resistance to ribociclib. RESULTS Baseline circulating tumor DNA was sequenced in 565 patients; 489 had evidence of ≥ 1 alteration. The most frequent alterations included PIK3CA (28%), TP53 (19%), CCND1 (10%), MYC (8%), GATA3 (8%), receptor tyrosine kinases (17%), and the Chr8p11.23 locus (12%). A treatment benefit of ribociclib was seen with wild-type (hazard ratio [HR] 0.45 [95% CI, 0.33 to 0.62]) and altered (HR 0.57 [95% CI, 0.36 to 0.9]) PIK3CA. Overall, patients with altered CCND1 had shorter PFS regardless of treatment, suggesting CCND1 as a potential prognostic biomarker. Benefit with ribociclib was seen in patients with altered (HR 0.21 [95% CI, 0.08 to 0.54]) or wild-type (HR 0.52 [95% CI, 0.39 to 0.68]) CCND1, but greater benefit was observed with altered, suggesting predictive potential of CCND1. Alterations in TP53, MYC, Chr8p11.23 locus, and receptor tyrosine kinases were associated with worse PFS, but ribociclib benefit was independent of alteration status. CONCLUSION In this study—to our knowledge, the first large study of premenopausal patients with hormone receptor–positive and human epidermal growth factor receptor 2–negative advanced breast cancer—multiple genomic alterations were associated with poor outcome. A PFS benefit of ribociclib was observed regardless of gene alteration status, although in this exploratory analysis, a magnitude of benefits varied by alteration.

scholarly journals TERT promoter hotspot mutations and gene amplification in metaplastic breast cancer

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Edaise M. da Silva ◽  
Pier Selenica ◽  
Mahsa Vahdatinia ◽  
Fresia Pareja ◽  
Arnaud Da Cruz Paula ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Gene Amplification ◽  
Genetic Alterations ◽  
Wild Type ◽  
Histologic Subtype ◽  
Exact Test ◽  
Fisher's Exact Test ◽  
Fisher’S Exact Test ◽  
Hotspot Mutations ◽  
Or Gene

AbstractMetaplastic breast cancers (MBCs) are characterized by complex genomes, which seem to vary according to their histologic subtype. TERT promoter hotspot mutations and gene amplification are rare in common forms of breast cancer, but present in a subset of phyllodes tumors. Here, we sought to determine the frequency of genetic alterations affecting TERT in a cohort of 60 MBCs with distinct predominant metaplastic components (squamous, 23%; spindle, 27%; osseous, 8%; chondroid, 42%), and to compare the repertoire of genetic alterations of MBCs according to the presence of TERT promoter hotspot mutations or gene amplification. Forty-four MBCs were subjected to: whole-exome sequencing (WES; n = 27) or targeted sequencing of 341-468 cancer-related genes (n = 17); 16 MBCs were subjected to Sanger sequencing of the TERT promoter, TP53 and selected exons of PIK3CA, HRAS, and BRAF. TERT promoter hotspot mutations (n = 9) and TERT gene amplification (n = 1) were found in 10 of the 60 MBCs analyzed, respectively. These TERT alterations were less frequently found in MBCs with predominant chondroid differentiation than in other MBC subtypes (p = 0.01, Fisher’s exact test) and were mutually exclusive with TP53 mutations (p < 0.001, CoMEt). In addition, a comparative analysis of the MBCs subjected to WES or targeted cancer gene sequencing (n = 44) revealed that MBCs harboring TERT promoter hotspot mutations or gene amplification (n = 6) more frequently harbored PIK3CA than TERT wild-type MBCs (n = 38; p = 0.001; Fisher’s exact test). In conclusion, TERT somatic genetic alterations are found in a subset of TP53 wild-type MBCs with squamous/spindle differentiation, highlighting the genetic diversity of these cancers.

Cell cycle arrest and astrocytic differentiation resulting from PTEN expression in glioma cells

1999 ◽  
Vol 91 (5) ◽  
pp. 822-830 ◽  
Author(s):  
Jun-ichi Adachi ◽  
Katsumi Ohbayashi ◽  
Tomonari Suzuki ◽  
Tomio Sasaki
Keyword(s):  
Expression System ◽  
Biological Significance ◽  
Glioma Cells ◽  
Genetic Alterations ◽  
Pten Expression ◽  
Human Glioma ◽  
Wild Type ◽  
Content Type ◽  
Astrocytic Differentiation ◽  
Fine Print

Object. Genetic alterations of the PTEN gene (also known as MMAC1 or TEP1) have frequently been identified in high-grade gliomas, indicating that inactivation of PTEN plays a crucial role in human glioma progression. The aim of this study was to assess the biological significance of PTEN inactivation in the development of glioma.Methods. The authors introduced wild-type PTEN complementary DNA into four human glioma cell lines (T98G, U-251MG, U-87MG, and A172) containing endogenous aberrant PTEN alleles. The number of colonies transfected with the wild-type PTEN was reduced to 15 to 32% of those found after transfection of a control vector, suggesting growth suppression by the exogenous PTEN. To analyze phenotypic alterations produced by PTEN expression, T98G-derived clones with inducible PTEN expression were further established using a tetracycline-regulated inducible gene expression system. Induction of PTEN expression suppressed the in vitro growth of T98G cells with accumulation of G1 phase cells. Furthermore, when cells were cultured in the presence of the extracellular matrix (ECM), PTEN expression caused distinct morphological changes, with multiple and elongated cytoplasmic processes similar to those of normal astrocytes. The level of glial fibrillary acidic protein, an intermediate protein specifically expressed in differentiated astrocytes, was upregulated concomitantly.Conclusions. These findings strongly indicate that exogenous PTEN expression inhibits the proliferation of glioma cells by inducing G1 arrest and elicits astrocytic differentiation in the presence of the ECM. Inactivation of PTEN would play an important role in the enhancement of unregulated growth of undifferentiated glioma cells.

scholarly journals Chemotherapy versus erlotinib as second-line treatment in patients with advanced non-small cell lung cancer and wild-type epidermal growth factor receptor: an individual patient data (IPD) analysis

ESMO Open ◽  
2018 ◽  
Vol 3 (6) ◽  
pp. e000327
Author(s):  
Marina Chiara Garassino ◽  
Tomoya Kawaguchi ◽  
Vanesa Gregorc ◽  
Eliana Rulli ◽  
Masahiko Ando ◽  
...  
Keyword(s):  
Epidermal Growth Factor Receptor ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Individual Patient Data ◽  
Growth Factor Receptor ◽  
Line Treatment ◽  
Second Line ◽  
Wild Type ◽  
Mean Survival Time ◽  
Epidermal Growth

The efficacy of second-line treatment in patients with epidermal growth factor receptor (EGFR) wild-type tumours is still debatable. We assessed the efficacy of a standard second-line chemotherapy compared with erlotinib in an individual patient data approach for meta-analysis. The primary endpoint was overall survival (OS), and secondary endpoint was progression-free survival (PFS). Both were compared by log-rank test. The ‘restricted mean survival time’ (RMST) was estimated in each study and the difference in mean survival time up to the last available time point was calculated. The Cox proportional hazards model was used on survival analyses to provide HRs, to adjust for confounding variables and to test possible interaction with selected factors. Three randomised trials comparing chemotherapy versus erlotinib were analysed, including 587 randomised patients. Overall, 74% of patients included in the original trials were considered. 464 deaths and 570 progressions or deaths were observed. Compared with erlotinib, chemotherapy was associated to a decreased risk of progression (29%; HR: 0.71, 95% CI: 0.60 to 0.84, p< 0.0001;) but with no statistical significant reduction in OS (HR: 0.89, 95% CI: 0.74 to 1.06; p<0.20). No heterogeneity was found in both analyses. Patients treated with chemotherapy gained an absolute 1.5 and 1.6 months, respectively, in PFS and lifetime (RMST 95% CI: PFS 0.49 to 2.44; OS 95% CI: −1.04 to 4.25). These results showed that patients without a constitutively activated EGFR had better PFS with chemotherapy rather than with erlotinib while no statistical difference was observed in OS.

scholarly journals SERCA Cys674 sulphonylation and inhibition of L-type Ca2+ influx contribute to cardiac dysfunction in endotoxemic mice, independent of cGMP synthesis

2013 ◽  
Vol 305 (8) ◽  
pp. H1189-H1200 ◽  
Author(s):  
Ion A. Hobai ◽  
Emmanuel S. Buys ◽  
Justin C. Morse ◽  
Jessica Edgecomb ◽  
Eric H. Weiss ◽  
...  
Keyword(s):  
Posttranslational Modifications ◽  
Cardiac Dysfunction ◽  
Ryanodine Receptors ◽  
Soluble Guanylyl Cyclase ◽  
Wild Type ◽  
Cellular Mechanisms ◽  
Channel Current ◽  
Lps Challenge ◽  
Cgmp Synthesis ◽  
Phospholamban Phosphorylation

The goal of this study was to identify the cellular mechanisms responsible for cardiac dysfunction in endotoxemic mice. We aimed to differentiate the roles of cGMP [produced by soluble guanylyl cyclase (sGC)] versus oxidative posttranslational modifications of Ca2+ transporters. C57BL/6 mice [wild-type (WT) mice] were administered lipopolysaccharide (LPS; 25 μg/g ip) and euthanized 12 h later. Cardiomyocyte sarcomere shortening and Ca2+ transients (ΔCai) were depressed in LPS-challenged mice versus baseline. The time constant of Ca2+ decay (τCa) was prolonged, and sarcoplasmic reticulum Ca2+ load (CaSR) was depressed in LPS-challenged mice (vs. baseline), indicating decreased activity of sarco(endo)plasmic Ca2+-ATPase (SERCA). L-type Ca2+ channel current ( ICa,L) was also decreased after LPS challenge, whereas Na+/Ca2+ exchange activity, ryanodine receptors leak flux, or myofilament sensitivity for Ca2+ were unchanged. All Ca2+-handling abnormalities induced by LPS (the decrease in sarcomere shortening, ΔCai, CaSR, ICa,L, and τCa prolongation) were more pronounced in mice deficient in the sGC main isoform (sGCα1−/− mice) versus WT mice. LPS did not alter the protein expression of SERCA and phospholamban in either genotype. After LPS, phospholamban phosphorylation at Ser16 and Thr17 was unchanged in WT mice and was increased in sGCα1−/− mice. LPS caused sulphonylation of SERCA Cys674 (as measured immunohistochemically and supported by iodoacetamide labeling), which was greater in sGCα1−/− versus WT mice. Taken together, these results suggest that cardiac Ca2+ dysregulation in endotoxemic mice is mediated by a decrease in L-type Ca2+ channel function and oxidative posttranslational modifications of SERCA Cys674, with the latter (at least) being opposed by sGC-released cGMP.

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