N-linked glycoproteomic profiling in esophageal squamous cell carcinoma

BACKGROUND Mass spectrometry-based proteomics and glycomics reveal post-translational modifications providing significant biological insights beyond the scope of genomic sequencing.AIM To characterize the N-linked glycoproteomic profile in esophageal squamous cell carcinoma(ESCC)via two complementary approaches.METHODS Using tandem multilectin affinity chromatography for enrichment of N-linked glycoproteins,we performed N-linked glycoproteomic profiling in ESCC tissues by two-dimensional gel electrophoresis(2-DE)-based and isobaric tags for relative and absolute quantification(iTRAQ)labeling-based mass spectrometry quantitation in parallel,followed by validation of candidate glycoprotein biomarkers by Western blot.RESULTS 2-DE-based and iTRAQ labeling-based quantitation identified 24 and 402 differentially expressed N-linked glycoproteins,respectively,with 15 in common,demonstrating the outperformance of iTRAQ labeling-based quantitation over 2-DE and complementarity of these two approaches.Proteomaps showed the distinct compositions of functional categories between proteins and glycoproteins with differential expression associated with ESCC.Western blot analysis validated the up-regulation of total procathepsin D and high-mannose procathepsin D,and the downregulation of total haptoglobin,high-mannose clusterin,and GlcNAc/sialic acid-containing fraction of 14-3-3ζ in ESCC tissues.The serum levels of glycosylated fractions of clusterin,prolinearginine-rich end leucine-rich repeat protein,and haptoglobin in patients with ESCC were remarkably higher than those in healthy controls.CONCLUSION Our study provides insights into the aberrant N-linked glycoproteome associated with ESCC,which will be a valuable resource for future investigations.

New perspectives on epigenetic modifications and PARP inhibitor resistance in HR-deficient cancers

The clinical treatment of DNA-repair defective tumours has been revolutionised by the use of poly(ADP)ribose polymerase(PARP)inhibitors.However,the efficacy of these compounds is hampered by resistance,which is attributed to numerous mechanisms including rewiring of the DNA damage response to favour pathways that repair PARP inhibitor-mediated damage.Here,we comment on recent findings by our group identifying the lysine methyltransferase SETD1A as a novel factor that conveys PARPi resistance.We discuss the implications,with a particular focus on epigenetic modifications and H3K4 methylation.We also deliberate on the mechanisms responsible,the consequences for the refinement of PARP inhibitor use in the clinic,and future possibilities to circumvent drug resistance in DNA-repair deficient cancers.

Genetic factors for differentiated thyroid cancer in French Polynesia:new candidate loci

Background:Populations of French Polynesia(FP),where France performed atmospheric tests between 1966 and 1974,experience a high incidence of differentiated thyroid cancer(DTC).However,up to now,no sufficiently large study of DTC genetic factors in this population has been performed to reach definitive conclusion.This research aimed to analyze the genetic factors of DTC risk among the native FP populations.Methods:We analyzed more than 300000 single nucleotide polymorphisms(SNPs)genotyped in 283 DTC cases and 418 matched controls born in FP,most being younger than 15 years old at the time of the first nuclear tests.We analyzed the genetic profile of our cohort to identify population subgroups.We then completed a genome-wide analysis study on the whole population.Results:We identified a specific genetic structure in the FP population reflecting admixture from Asian and European populations.We identified three regions associated with increased DTC risk at 6q24.3,10p12.2,and 17q21.32.The lead SNPs at these loci showed respective p-values of 1.66×10^(−7),2.39×10^(−7),and 7.19×10^(−7) and corresponding odds ratios of 2.02,1.89,and 2.37.Conclusion:Our study results suggest a role of the loci 6q24.3,10p12.2 and 17q21.32 in DTC risk.However,a whole genome sequencing approach would be better suited to characterize these factors than genotyping with microarray chip designed for the Caucasian population.Moreover,the functional impact of these three new loci needs to be further explored and validated.

Heterogeneity of germline variants in high risk breast and ovarian cancer susceptibility genes in India

Breast and ovarian cancers now account for one in three cancers in Indian women and their incidence is rising.Major differences in the clinical presentation of breast and ovarian cancers exist between India and the United Kingdom.For example,Indian patients with breast cancer typically present a decade earlier than in the UK.Reasons for this could be multifactorial,including differences in underlying biology,environmental risks,and other systematic factors including access to screening.One possible explanation lies in variable incidence or penetrance of germline mutations in genes such as BRCA1 and BRCA2.We performed a methodical database and literature review to investigate the prevalence and spectrum of high-risk cancer susceptibility genes in Indian patients with breast and ovarian cancers.We identified 148 articles,but most studies were small,with inconsistent inclusion criteria and based on heterogeneous technologies,so that mutation frequency could not be reliably ascertained.Data were also often lacking on penetrance,histopathology,and survival outcomes.After filtering out unsuitable studies,only 13 remained,comprising 1028 patients.Large-scale research studies are urgently needed to determine mutation prevalence,spectra,and clinico-pathological features,and hence derive guidelines for screening,treatment,and prevention specific to the Indian population.

Traumatic injury is associated with reduced deoxyribonuclease activity and dysregulation of the actin scavenging system

Background:Traumatic injury is associated with increased concentrations of cell-free DNA(cfDNA)in the circulation,which contribute to post-injury complications.The endonuclease deoxyribonuclease 1(DNase-1)is responsible for removing 90%of circulating cfDNA.Recently,DNase activity was reported to be significantly reduced following major non-traumatic brain injury(TBI),but the processes responsible were not investigated.Moreover,it is not known how quickly following injury DNase activity is reduced and whether this also occurs after TBI.Methods:At 3 post-injury time points(≤1,4–12 and 48–72 hours),blood samples were obtained from 155 adult trauma patients that had sustained an isolated TBI(n=21),TBI with accompanying extracranial injury(TBI^(+))(n=53)or an extracranial injury only(ECI)(n=81).In addition to measuring cfDNA levels and the activity and expression of DNase,circulating concentrations of monomeric globular action(G-actin),an inhibitor of DNase-1,and the actin scavenging proteins gelsolin(GSN)and vitamin D binding protein(VDBP)were determined and values compared to a cohort of healthy controls.Results:Significantly elevated concentrations of plasma cfDNA were seen in TBI,TBI^(+)and ECI patients at all study time points when compared to healthy controls.cfDNA levels were significantly higher at≤1 hour post-injury in ECI patients who subsequently developed multiple organ dysfunction syndrome when compared to those who did not.Plasma DNase-1 protein was significantly elevated in all patient groups at all sampling time points.In contrast,DNase enzyme activity was significantly reduced,with this impaired function evident in TBI^(+)patients within minutes of injury.Circulating concentrations of G-actin were elevated in all patient cohorts in the immediate aftermath of injury and this was accompanied by a significant reduction in the levels of GSN and VDBP.Conclusions:The post-traumatic increase in circulating cfDNA that occurs following extracranial trauma and TBI is accompanied by reduced DNase activity.We propose that,secondary to reduced GSN and VDBP levels,elevated circulating concentrations of G-actin underlie the post-injury reduction in DNase activity.Reducing circulating cfDNA levels via therapeutic restoration of DNase-1 activity may improve clinical outcomes post-injury.

大血管手术的术前锻炼优化措施

大血管手术,例如主动脉瘤修复、颈动脉内膜切除、下肢再血管化等,发病率逐年升高,且都有着很高的风险。全世界约2亿以上的患者都患有外周血管疾病,其中约10%~20%需行手术治疗。在英国,在65岁以上男性人群中,约1.2%~1.5%患有腹主动脉瘤,在2017年共进行了超过4000台腹主动脉瘤修复手术。另外,约7%~18%的脑卒中患者的病因为颈动脉狭窄。在英国,每年有超过4000例患者进行了颈动脉内膜切除手术。