The application of antimicrobial peptides (AMPs) is largely hindered by their non-specific toxicity against mammalian cells, which is usually associated with helical structure, hydrophobicity, and charge density. A random coil-to-helix transition mechanism has now been introduced into the design of AMPs, minimizing the toxicity against mammalian cells while maintaining high antimicrobial activity. By incorporating anionic phosphorylated tyrosine into the cationic polypeptide, the helical structure of AMPs was distorted owing to the side-chain charge interaction. Together with the decreased charge density, the AMPs exhibited inhibited toxicity against mammalian cells. At the infectious site, the AMPs can be activated by bacterial phosphatase to restore the helical structure, thus contributing to strong membrane disruptive capability and potent antimicrobial activity. This bacteria-activated system is an effective strategy to enhance the therapeutic selectivity of AMPs.
Controlling the topology of polymer-modified proteins has attracted growing interest. However, one of the main challenges in this field is the lack of efficient and site-specific methods for installing multiple bioorthogonal functionalities on substrate polymers. We report here an orchestrating strategy that provides easy access to various topological protein-poly(amino acid) (PAA) conjugates in high yields. This method features the in situ installation of two "chemical handles", including a thioester for native chemical ligation and a polyglycine nucleophile for sortase A-mediated ligation, at both ends of substrate PAAs. As a result, neither pre-functionalization of initiator or monomer units, nor post-polymerization modification of the resultant polymers, is necessary. Site-specific topological conjugates, particularly circular conjugates, can be conveniently synthesized under mild conditions from the functionalized PAAs. The biomedical utility of our method is demonstrated by the rapid and efficient generation of several therapeutic interferon-α conjugates, which exhibit significantly enhanced protease resistance and thermostability. Given the versatility of both PAAs and proteins, the method offers a convenient approach to producing libraries of conjugates for biological applications.
Purpose: Genomic analyses of small-cell lung cancer (SCLC) are limited by the availability of tumor specimens. This study aimed to investigate the suitability of single-cell sequencing of circulating tumor cells (CTC) as a method of inferring the evolution and progression of SCLCs.
Purpose: Chemoresistance in small-cell lung cancer (SCLC) is reportedly attributed to the existence of resistant cancer stem cells (CSC). Studies involving CSC-specific markers and related mechanisms in SCLC remain limited. This study explored the role of the voltage-dependent calcium channel a2d1 subunit as a CSC marker in chemoresistance of SCLC, and explored the potential mechanisms of a2d1-mediated chemoresistance and strategies of overcoming the resistance. Experimental Design: a2d1-positive cells were identified and isolated from SCLC cell lines and patient-derived xenograft (PDX) models, and CSC-like properties were subsequently verified. Transcriptome sequencing and Western blotting were carried out to identify pathways involved in a2d1mediated chemoresistance in SCLC. In addition, possible interventions to overcome a2d1-mediated chemoresistance were examined. Results: Different proportions of a2d1 þ cells were identified in SCLC cell lines and PDX models. a2d1 þ cells exhibited CSClike properties (self-renewal, tumorigenic, differentiation potential, and high expression of genes related to CSCs and drug resistance). Chemotherapy induced the enrichment of a2d1 þ cells instead of CD133 þ cells in PDXs, and an increased proportion of a2d1 þ cells corresponded to increased chemoresistance. Activation and overexpression of ERK in the a2d1-positive H1048 cell line was identified at the protein level. mAb 1B50-1 was observed to improve the efficacy of chemotherapy and delay relapse as maintenance therapy in PDX models. Conclusions: SCLC cells expressing a2d1 demonstrated CSClike properties, and may contribute to chemoresistance. ERK may play a key role in a2d1-mediated chemoresistance. mAb 1B50-1 may serve as a potential anti-SCLC drug. Clin Cancer Res; 24(9); 2148-58. Ó2018 AACR.
BackgroundEpidermal growth factor receptor (EGFR) mutations, including a known exon 19 deletion (19 del) and exon 21 L858R point mutation (L858R mutation), are strong predictors of the response to EGFR tyrosine kinase inhibitor (EGFR-TKI) treatment in lung adenocarcinoma. However, whether patients carrying EGFR 19 del and L858R mutations exhibit different responsiveness to EGFR-TKIs and what are the potential mechanism for this difference remain controversial. This study aimed to investigate the clinical outcomes of EGFR-TKI treatment in patients with EGFR 19 del and L858R mutations and explore the genetic heterogeneity of tumors with the two mutation subtypes.MethodsOf 1127 patients with advanced lung adenocarcinoma harboring EGFR 19 del or L858R mutations, 532 received EGFR-TKI treatment and were included in this study. EGFR 19 del and L858R mutations were detected by using denaturing high-performance liquid chromatography (DHPLC). T790M mutation, which is a common resistant mutation on exon 20 of EGFR, was detected by amplification refractory mutation system (ARMS). Next-generation sequencing (NGS) was used to explore the genetic heterogeneity of tumors with EGFR 19 del and L858R mutations.ResultsOf the 532 patients, 319 (60.0%) had EGFR 19 del, and 213 (40.0%) had L858R mutations. The patients with EGFR 19 del presented a significantly higher overall response rate (ORR) for EGFR-TKI treatment (55.2% vs. 43.7%, P = 0.017) and had a longer progression-free survival (PFS) after first-line EGFR-TKI treatment (14.4 vs. 11.4 months, P = 0.034) compared with those with L858R mutations. However, no statistically significant difference in overall survival (OS) was observed between the two groups of patients. T790M mutation status was analyzed in 88 patients before EGFR-TKI treatment and 134 after EGFR-TKI treatment, and there was no significant difference in the co-existence of T790M mutation with EGFR 19 del and L858R mutations before EGFR-TKI treatment (5.6% vs. 8.8%, P = 0.554) or after treatment (24.4% vs. 35.4%, P = 0.176). In addition, 24 patients with EGFR 19 del and 19 with L858R mutations were analyzed by NGS, and no significant difference in the presence of multiple somatic mutations was observed between the two genotypes.ConclusionsPatients with EGFR 19 del exhibit longer PFS and higher ORR compared with those with L858R mutations. Whether the heterogeneity of tumors with EGFR 19 del and L858R mutations contribute to a therapeutic response difference needs further investigation.
The shell color polymorphism widely exists in economic shellfish, which not only results in a better visual perception but also shows great value as an economic trait for breeding. Small numbers of reddish-orange shell Yesso scallops, Patinopecten yessoensis, were found in cultured populations compared to the brown majority. In this study, a genome-wide association study was conducted to understand the genetic basis of shell color. Sixty-six 2b-RAD libraries with equal numbers of reddish-orange and brown shell individuals were constructed and sequenced using the Illumina HiSeq 2000 platform. A total of 322,332,684 high-quality reads were obtained, and the average sequencing depth was 18.4×. One genomic region on chromosome 11 that included 239 single-nucleotide polymorphisms (SNPs) was identified as significantly associated with shell color. After verification by high-resolution melting in another population, two SNPs were selected as specific loci for reddish-orange shell color. These two SNPs could be used to improve the selective breeding progress of true-breeding strains with complete reddish-orange scallops. In addition, within the significantly associated genomic region, candidate genes were identified using marker sequences to search the draft genome of Yesso scallop. Three genes (LDLR, FRIS, and FRIY) with known functions in carotenoid metabolism were identified. Further study using high-performance liquid chromatography proved that the relative level of carotenoids in the reddish-orange shells was 40 times higher than that in the brown shells. These results suggested that the accumulation of carotenoids contributes to the formation of reddish-orange shells.
BackgroundThe Th1 cell-specific transcription factor TBX21 functions as a regulator of expression of a Th1 cytokine, interferon gamma (IFN-γ). However, the specific function of TBX21 correlated with cancer stemness remains unclear.MethodsUsing univariate and multivariate survival analysis, TBX21was identified as an independent predictive factor and was associated with poor prognosis in 1389 patients with lung adenocarcinoma (LUAD). Its mechanism in the prognosis was explored by functional enrichment analysis and validated in bioexperiments.ResultsIn the training and test sets, TBX21 could classify 1389 LUAD patients into high and low-risk groups with significantly different prognosis (P < 0.01). Its prognostic power was independent of other clinical factors including stage, age, gender and smoking status. Functional studies indicated that downregulating TBX21 in lung cancer cells decreased the fraction of cancer stem cells and their sphere and tumor initiation frequency. Furthermore, the study showed that TBX21 activation transduced a TBX21–IL-4 signaling cascade to promote tumor initiation, tumor growth and expression of stemness markers.ConclusionsThese data demonstrated a key role of TBX21 in the maintenance of cancer stemness and that the TBX21–IL-4 pathway is a crucial factor contributing to lung carcinogenesis.Graphical abstractTBX21 prognostic model correlated with cancer stemness via TBX21-IL-4 pathway in LUAD patientsElectronic supplementary materialThe online version of this article (10.1186/s13287-018-0820-6) contains supplementary material, which is available to authorized users.
BackgroundChildhood Takayasu’s arteritis (c-TA) is scarcely reported but is characterized by devastating morbidity and mortality. This study aims to investigate the clinical course of c-TA and prognostic factors associated with rehospitalization and events including vascular complications, flares, and death.MethodsAn ambispective study of 101 c-TA patients satisfying the American College of Rheumatology (ACR) criteria and/or the European League against Rheumatism (EULAR)/Pediatric Rheumatology International Trials Organization (PRINTO)/Pediatric Rheumatology European Society (PReS) criteria was conducted from January 2002 to December 2017. Data on demographic, clinical, laboratory, imaging, and therapeutic features were collected. Event-free survival, complication-free survival, flare-free survival, rehospitalization-free survival, and associated prognostic factors were assessed by Kaplan-Meier survival curve and propensity score analysis.ResultsThe median age at c-TA onset was 14 (interquartile range (IQR) 12–16) years and 76.2% were female. Hypertension (70.3%), blood pressure discrepancy (55.4%), bruits (51.5%), and pulse deficits (37.6%) were core presentations. Major vascular involvement included the renal artery (62.4%), abdominal aorta (42.6%), subclavian artery (43.6%), and carotid artery (42.6%). Glucocorticoids (78.2%), antihypertensive drugs (72.3%), antiplatelet agents (72.3%), and revascularization (57.4%) were made up the majority administered. At a median 2.4 (IQR 0.7–6.1) years of follow-up, events, rehospitalization, vascular complications, flares and death were observed in 44.6%, 37.6%, 44.6%, 26.7%, and 3%, respectively. The 5-year event-free survival, rehospitalization-free survival, vascular complication-free survival, and flare-free survival were 42.8%, 55.8%, 45.9%, and 62.3%, respectively. Body mass index (BMI) (hazard ratio (HR) = 0.49, 95% confidence interval (CI) 0.30–0.81, p = 0.005), stroke (HR = 7.37, 95% CI 2.35–23.1, p = 0.001), and revascularization (HR = 0.51, 95% CI 0.27–0.94, p = 0.032) were independent prognostic predictors of events. Predictors for rehospitalization include age at admission (HR = 0.81, 95% CI 0.69–0.94, p = 0.006), renal artery involvement (HR = 0.49, 95% CI 0.25–0.96, p = 0.037), and elevated C-reactive protein (CRP; HR = 2.50, 95% CI 1.24–5.00, p = 0.01). BMI level (p = 0.024) and renal artery involvement (p = 0.015) were also associated with vascular complications, while revascularization (p = 0.002) independently correlated with re-flares.ConclusionsThis large ambispective study of c-TA revealed an early 3% mortality at the first year and around 50% morbidity within 5 years after diagnosis. Hypertension, renal artery involvement, and revascularization based on anti-inflammation, antihypertension, and antiplatelet medications dominated c-TA with indications for optimistic prognosis. Patients with initial lower BMI level, a younger age at admission, stroke, and elevated CRP have a high risk of poor outcomes, requiring close c-TA monitoring and more aggressiv...
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