-
Annals of Oncology : Official Journal... Jun 2024Amivantamab-lazertinib significantly prolonged progression-free survival (PFS) versus osimertinib in patients with epidermal growth factor receptor (EGFR)-mutant...
Amivantamab plus lazertinib versus osimertinib in first-line EGFR-mutant advanced non-small-cell lung cancer with biomarkers of high-risk disease: a secondary analysis from MARIPOSA.
BACKGROUND
Amivantamab-lazertinib significantly prolonged progression-free survival (PFS) versus osimertinib in patients with epidermal growth factor receptor (EGFR)-mutant advanced non-small-cell lung cancer [NSCLC; hazard ratio (HR) 0.70; P < 0.001], including those with a history of brain metastases (HR 0.69). Patients with TP53 co-mutations, detectable circulating tumor DNA (ctDNA), baseline liver metastases, and those without ctDNA clearance on treatment have poor prognoses. We evaluated outcomes in these high-risk subgroups.
PATIENTS AND METHODS
This analysis included patients with treatment-naive, EGFR-mutant advanced NSCLC randomized to amivantamab-lazertinib (n = 429) or osimertinib (n = 429) in MARIPOSA. Pathogenic alterations were identified by next-generation sequencing (NGS) of baseline blood ctDNA with Guardant360 CDx. Ex19del and L858R ctDNA in blood was analyzed at baseline and cycle 3 day 1 (C3D1) with Biodesix droplet digital polymerase chain reaction (ddPCR).
RESULTS
Baseline ctDNA for NGS of pathogenic alterations was available for 636 patients (amivantamab-lazertinib, n = 320; osimertinib, n = 316). Amivantamab-lazertinib improved median PFS (mPFS) versus osimertinib for patients with TP53 co-mutations {18.2 versus 12.9 months; HR 0.65 [95% confidence interval (CI) 0.48-0.87]; P = 0.003} and for patients with wild-type TP53 [22.1 versus 19.9 months; HR 0.75 (95% CI 0.52-1.07)]. In patients with EGFR-mutant, ddPCR-detectable baseline ctDNA, amivantamab-lazertinib significantly prolonged mPFS versus osimertinib [20.3 versus 14.8 months; HR 0.68 (95% CI 0.53-0.86); P = 0.002]. Amivantamab-lazertinib significantly improved mPFS versus osimertinib in patients without ctDNA clearance at C3D1 [16.5 versus 9.1 months; HR 0.49 (95% CI 0.27-0.87); P = 0.015] and with clearance [24.0 versus 16.5 months; HR 0.64 (95% CI 0.48-0.87); P = 0.004]. Amivantamab-lazertinib significantly prolonged mPFS versus osimertinib among randomized patients with [18.2 versus 11.0 months; HR 0.58 (95% CI 0.37-0.91); P = 0.017] and without baseline liver metastases [24.0 versus 18.3 months; HR 0.74 (95% CI 0.60-0.91); P = 0.004].
CONCLUSIONS
Amivantamab-lazertinib effectively overcomes the effect of high-risk features and represents a promising new standard of care for patients with EGFR-mutant advanced NSCLC.
PubMed: 38942080
DOI: 10.1016/j.annonc.2024.05.541 -
ELife Jun 2024Genetic diversity is a hallmark of RNA viruses and the basis for their evolutionary success. Taking advantage of the uniquely large genomic database of SARS-CoV-2, we...
Genetic diversity is a hallmark of RNA viruses and the basis for their evolutionary success. Taking advantage of the uniquely large genomic database of SARS-CoV-2, we examine the impact of mutations across the spectrum of viable amino acid sequences on the biophysical phenotypes of the highly expressed and multifunctional nucleocapsid protein. We find variation in the physicochemical parameters of its extended intrinsically disordered regions (IDRs) sufficient to allow local plasticity, but also observe functional constraints that similarly occur in related coronaviruses. In biophysical experiments with several N-protein species carrying mutations associated with major variants, we find that point mutations in the IDRs can have nonlocal impact and modulate thermodynamic stability, secondary structure, protein oligomeric state, particle formation, and liquid-liquid phase separation. In the Omicron variant, distant mutations in different IDRs have compensatory effects in shifting a delicate balance of interactions controlling protein assembly properties, and include the creation of a new protein-protein interaction interface in the N-terminal IDR through the defining P13L mutation. A picture emerges where genetic diversity is accompanied by significant variation in biophysical characteristics of functional N-protein species, in particular in the IDRs.
Topics: SARS-CoV-2; Coronavirus Nucleocapsid Proteins; Mutation; COVID-19; Humans; Intrinsically Disordered Proteins; Phosphoproteins; Nucleocapsid Proteins; Thermodynamics; Protein Stability
PubMed: 38941236
DOI: 10.7554/eLife.94836 -
ELife Jun 2024A new study reveals how naturally occurring mutations affect the biophysical properties of nucleocapsid proteins in SARS-CoV-2.
A new study reveals how naturally occurring mutations affect the biophysical properties of nucleocapsid proteins in SARS-CoV-2.
Topics: SARS-CoV-2; Mutation; COVID-19; Humans; Coronavirus Nucleocapsid Proteins; Phosphoproteins
PubMed: 38941233
DOI: 10.7554/eLife.99991 -
STAR Protocols Jun 2024A gene-rescue experiment under a mutant background is essential to clarify gene function and the resulting biological potential in vivo. Here, we present a protocol for...
A gene-rescue experiment under a mutant background is essential to clarify gene function and the resulting biological potential in vivo. Here, we present a protocol for determining the change in interferon response by microinjecting plasmids into one-cell-stage zebrafish embryos. We describe steps for comparing the resistance potential to virus infection in wild-type and knockout zebrafish larvae following plasmid microinjection. We then detail how to link the enhanced interferon immunity to the improved resistance in knockout zebrafish larvae by gene-rescue experiments. For complete details on the use and execution of this protocol, please refer to Qu et al..
PubMed: 38941183
DOI: 10.1016/j.xpro.2024.103156 -
Cancer Science Jun 2024Osimertinib induces a marked response in non-small-cell lung cancer (NSCLC) patients harboring epidermal growth factor receptor (EGFR) gene mutations. However, acquired...
Osimertinib induces a marked response in non-small-cell lung cancer (NSCLC) patients harboring epidermal growth factor receptor (EGFR) gene mutations. However, acquired resistance to osimertinib remains an inevitable problem. In this study, we aimed to investigate osimertinib-resistant mechanisms and evaluate the combination therapy of afatinib and chemotherapy. We established osimertinib-resistant cell lines (PC-9-OR and H1975-OR) from EGFR-mutant lung adenocarcinoma cell lines PC-9 and H1975 by high exposure and stepwise method. Combination therapy of afatinib plus carboplatin (CBDCA) and pemetrexed (PEM) was effective in both parental and osimertinib-resistant cells. We found that expression of thrombospondin-1 (TSP-1) was upregulated in resistant cells using cDNA microarray analysis. We demonstrated that TSP-1 increases the expression of matrix metalloproteinases through integrin signaling and promotes tumor invasion in both PC-9-OR and H1975-OR, and that epithelial-to-mesenchymal transition (EMT) was involved in H1975-OR. Afatinib plus CBDCA and PEM reversed TSP-1-induced invasion ability and EMT changes in resistant cells. In PC-9-OR xenograft mouse models (five female Balb/c-Nude mice in each group), combination therapy strongly inhibited tumor growth compared with afatinib monotherapy (5 mg/kg, orally, five times per week) or CBDCA (75 mg/kg, intraperitoneally, one time per week) + PEM (100 mg/kg, intraperitoneally, one time per week) over a 28-day period. These results suggest that the combination of afatinib plus CBDCA and PEM, which effectively suppresses TSP-1 expression, may be a promising option in EGFR-mutated NSCLC patients after the acquisition of osimertinib resistance.
PubMed: 38941131
DOI: 10.1111/cas.16199 -
Membrane protein Bcsdr2 mediates biofilm integrity, hyphal growth and virulence of Botrytis cinerea.Applied Microbiology and Biotechnology Jun 2024Grey mould caused by Botrytis cinerea is a devastating disease responsible for large losses to agricultural production, and B. cinerea is a necrotrophic model fungal...
Grey mould caused by Botrytis cinerea is a devastating disease responsible for large losses to agricultural production, and B. cinerea is a necrotrophic model fungal plant pathogen. Membrane proteins are important targets of fungicides and hotspots in the research and development of fungicide products. Wuyiencin affects the permeability and pathogenicity of B. cinerea, parallel reaction monitoring revealed the association of membrane protein Bcsdr2, and the bacteriostatic mechanism of wuyiencin was elucidated. In the present work, we generated and characterised ΔBcsdr2 deletion and complemented mutant B. cinerea strains. The ΔBcsdr2 deletion mutants exhibited biofilm loss and dissolution, and their functional activity was illustrated by reduced necrotic colonisation on strawberry and grape fruits. Targeted deletion of Bcsdr2 also blocked several phenotypic defects in aspects of mycelial growth, conidiation and virulence. All phenotypic defects were restored by targeted gene complementation. The roles of Bcsdr2 in biofilms and pathogenicity were also supported by quantitative real-time RT-PCR results showing that phosphatidylserine decarboxylase synthesis gene Bcpsd and chitin synthase gene BcCHSV II were downregulated in the early stages of infection for the ΔBcsdr2 strain. The results suggest that Bcsdr2 plays important roles in regulating various cellular processes in B. cinerea. KEY POINTS: • The mechanism of wuyiencin inhibits B. cinerea is closely associated with membrane proteins. • Wuyiencin can downregulate the expression of the membrane protein Bcsdr2 in B. cinerea. • Bcsdr2 is involved in regulating B. cinerea virulence, growth and development.
Topics: Botrytis; Biofilms; Virulence; Hyphae; Plant Diseases; Fragaria; Fungal Proteins; Membrane Proteins; Vitis; Spores, Fungal; Gene Deletion
PubMed: 38940906
DOI: 10.1007/s00253-024-13238-8 -
MBio Jun 2024Inositol pyrophosphate 1,5-IP regulates expression of a fission yeast phosphate homeostasis regulon, comprising phosphate acquisition genes , , and , via its action as...
UNLABELLED
Inositol pyrophosphate 1,5-IP regulates expression of a fission yeast phosphate homeostasis regulon, comprising phosphate acquisition genes , , and , via its action as an agonist of precocious termination of transcription of the upstream lncRNAs that repress mRNA synthesis. 1,5-IP levels are dictated by a balance between the Asp1 N-terminal kinase domain that converts 5-IP to 1,5-IP and three inositol pyrophosphatases-the Asp1 C-terminal domain (a histidine acid phosphatase), Siw14 (a cysteinyl-phosphatase), and Aps1 (a Nudix enzyme). In this study, we report the biochemical and genetic characterization of Aps1 and an analysis of the effects of Asp1, Siw14, and Aps1 mutations on cellular inositol pyrophosphate levels. We find that Aps1's substrate repertoire embraces inorganic polyphosphates, 5-IP, 1-IP, and 1,5-IP. Aps1 displays a ~twofold preference for hydrolysis of 1-IP versus 5-IP and ∆ cells have twofold higher levels of 1-IP vis-à-vis wild-type cells. While neither Aps1 nor Siw14 is essential for growth, an ∆ ∆ double mutation is lethal on YES medium. This lethality is a manifestation of IP toxicosis, whereby excessive 1,5-IP drives derepression of leading to Tgp1-mediated uptake of glycerophosphocholine. We were able to recover an ∆ ∆ mutant on ePMGT medium lacking glycerophosphocholine and to suppress the severe growth defect of ∆ ∆ on YES by deleting . However, the severe growth defect of an ∆ strain could not be alleviated by deleting , suggesting that 1,5-IP levels in this double-pyrophosphatase mutant exceed a threshold beyond which overzealous termination affects other genes, which results in cytotoxicity.
IMPORTANCE
Repression of the fission yeast genes , , and by lncRNA-mediated interference is sensitive to changes in the metabolism of 1,5-IP, a signaling molecule that acts as an agonist of precocious lncRNA termination. 1,5-IP is formed by phosphorylation of 5-IP and catabolized by inositol pyrophosphatases from three distinct enzyme families: Asp1 (a histidine acid phosphatase), Siw14 (a cysteinyl phosphatase), and Aps1 (a Nudix hydrolase). This study entails a biochemical characterization of Aps1 and an analysis of how Asp1, Siw14, and Aps1 mutations impact growth and inositol pyrophosphate pools . Aps1 catalyzes hydrolysis of inorganic polyphosphates, 5-IP, 1-IP, and 1,5-IP , with a ~twofold preference for 1-IP over 5-IP. ∆ cells have twofold higher levels of 1-IP than wild-type cells. An ∆ ∆ double mutation is lethal because excessive 1,5-IP triggers derepression of , leading to toxic uptake of glycerophosphocholine.
PubMed: 38940614
DOI: 10.1128/mbio.01084-24 -
MBio Jun 2024Transposon sequencing (Tn-seq) is a powerful genome-wide technique to assess bacterial fitness under varying growth conditions. However, screening via Tn-seq is...
UNLABELLED
Transposon sequencing (Tn-seq) is a powerful genome-wide technique to assess bacterial fitness under varying growth conditions. However, screening via Tn-seq is challenging. Dose limitations and host restrictions create bottlenecks that diminish the transposon mutant pool being screened. Here, we have developed a murine model with a disruption in that renders the resulting RECON mouse resistant to high-dose infection. We leveraged this model to perform a Tn-seq screen of the human pathogen . We identified 135 genes which were required for growth in mice including novel genes not previously identified for host survival. We identified organ-specific requirements for survival and investigated the role of the folate enzyme FolD in liver pathogenesis. A mutant lacking was impaired for growth in murine livers by 2.5-log compared to wild type and failed to spread cell-to-cell in fibroblasts. In contrast, a mutant in which encodes a transcription factor that represses an operon involved in D-allose catabolism, was attenuated in both livers and spleens of mice by 4-log and 3-log, respectively, but showed modest phenotypes in models. We confirmed that dysregulation of the D-allose catabolism operon is responsible for the growth defect, as deletion of the operon in the ∆ background rescued virulence. By undertaking an unbiased, genome-wide screen in mice, we have identified novel fitness determinants for host infection, which highlights the utility of the RECON mouse model for future screening efforts.
IMPORTANCE
is the gram-positive bacterium responsible for the food-borne disease listeriosis. Although infections with are limiting in healthy hosts, vulnerable populations, including pregnant and elderly people, can experience high rates of mortality. Thus, understanding the breadth of genetic requirements for survival will present new opportunities for treatment and prevention of listeriosis. We developed a murine model of infection using a RECON mouse that is restrictive to systemic infection. We utilized this model to screen for genes required via transposon sequencing. We identified the liver-specific gene and a repressor, , that only exhibits an growth defect. AlsR controls the expression of the D-allose operon which is a marker in diagnostic techniques to identify pathogenic . A better understanding of the role of the D-allose operon in human disease may further inform diagnostic and prevention measures.
PubMed: 38940553
DOI: 10.1128/mbio.01332-24 -
MSphere Jun 2024The adaptation of gene deletion methods based on the CRISPR-Cas9 system has facilitated the genetic manipulation of the pathogenic yeast , because homozygous mutants of...
Probing gene function in wild-type strains by Cas9-facilitated one-step integration of two dominant selection markers: a systematic analysis of recombination events at the target locus.
UNLABELLED
The adaptation of gene deletion methods based on the CRISPR-Cas9 system has facilitated the genetic manipulation of the pathogenic yeast , because homozygous mutants of this diploid fungus can now be generated in a single step, allowing the rapid screening of candidate genes for their involvement in a phenotype of interest. However, the Cas9-mediated double-strand breaks at the target site may result in an undesired loss of heterozygosity (LOH) on the affected chromosome and cause phenotypic alterations that are not related to the function of the investigated gene. In our present study, we harnessed Cas9-facilitated gene deletion to probe a set of genes that are constitutively overexpressed in strains containing hyperactive forms of the transcription factor Mrr1 for a possible contribution to the fluconazole resistance of such strains. To this aim, we used gene deletion cassettes containing two different dominant selection markers, and , which confer resistance to nourseothricin and hygromycin, respectively, for simultaneous genomic integration in a single step, hypothesizing that this would minimize undesired LOH events at the target locus. We found that selection for resistance to both nourseothricin and hygromycin strongly increased the proportion of homozygous deletion mutants among the transformants compared with selection on media containing only one of the antibiotics, but it did not avoid undesired LOH events. Our results demonstrate that LOH on the target chromosome is a significant problem when using Cas9 for the generation of gene deletion mutants, which demands a thorough examination of recombination events at the target site.
IMPORTANCE
is one of the medically most important fungi and a model organism to study fungal pathogenicity. Investigating gene function in this diploid yeast has been facilitated by the adaptation of gene deletion methods based on the bacterial CRISPR-Cas9 system, because they enable the generation of homozygous mutants in a single step. We found that, in addition to increasing the efficiency of gene replacement by selection markers, the Cas9-mediated double-strand breaks also result in frequent loss of heterozygosity on the same chromosome, even when two different selection markers were independently integrated into the two alleles of the target gene. Since loss of heterozygosity for other genes can result in phenotypic alterations that are not caused by the absence of the target gene, these findings show that it is important to thoroughly analyze recombination events at the target locus when using Cas9 to generate gene deletion mutants in .
PubMed: 38940507
DOI: 10.1128/msphere.00388-24 -
Oncology Letters Aug 2024Glioblastoma multiforme (GBM) is an aggressive brain cancer that occurs more frequently than other brain tumors. The present study aimed to reveal a novel mechanism of...
Glioblastoma multiforme (GBM) is an aggressive brain cancer that occurs more frequently than other brain tumors. The present study aimed to reveal a novel mechanism of temozolomide resistance in GBM using bioinformatics and wet lab analyses, including meta-Z analysis, Kaplan-Meier survival analysis, protein-protein interaction (PPI) network establishment, cluster analysis of co-expressed gene networks, and hierarchical clustering of upregulated and downregulated genes. Next-generation sequencing and quantitative PCR analyses revealed downregulated [tyrosine kinase with immunoglobulin and epidermal growth factor homology domains 1 (), calcium voltage-gated channel auxiliary subunit α2Δ1 (), calpain 6 () and a disintegrin and metalloproteinase with thrombospondin motifs 6 ()] and upregulated [serum amyloid (), growth differentiation factor 15 () and ubiquitin specific peptidase 26 ()] genes. Different statistical models were developed for these genes using the Z-score for P-value conversion, and Kaplan-Meier plots were constructed using several patient cohorts with brain tumors. The highest number of nodes was observed in the PPI network was for and . The PPI network model for all genes contained 35 nodes and 241 edges. Immunohistochemical staining was performed using isocitrate dehydrogenase (IDH)-wild-type or IDH-mutant GBM samples from patients and a significant upregulation of TIE1 (P<0.001) and CAPN6 (P<0.05) protein expression was demonstrated in IDH-mutant GBM in comparison with IDH-wild-type GBM. Structural analysis revealed an IDH-mutant model demonstrating the mutant residues (R132, R140 and R172). The findings of the present study will help the future development of novel biomarkers and therapeutics for brain tumors.
PubMed: 38939621
DOI: 10.3892/ol.2024.14511