When speed is of the essence: After photoisomerization to its metastable cis form, an azo dye must undergo fast thermal isomerization back to the trans form to be suitable for real‐time information ...transmission. The azopyrimidine shown has a relaxation time (τ) of just 40 ns under physiological conditions, as well as high biocompatibility, as determined by Escherichia coli growth in its presence (see picture).
We report a quantitative proteomics data analysis pipeline, which coupled to protein‐directed dynamic combinatorial chemistry (DDC) experiments, enables the rapid discovery and direct ...characterization of protein‐protein interaction (PPI) modulators. A low‐affinity PD‐1 binder was incubated with a library of >100 D‐peptides under thiol‐exchange favoring conditions, in the presence of the target protein PD‐1, and we determined the S‐linked dimeric species that resulted, amplified in the protein samples versus the controls. We chemically synthesized the target dimer candidates and validated them by thermophoresis binding and protein‐protein interaction assays. The results provide a proof‐of‐concept for using this strategy in the high‐throughput search of improved drug‐like peptide binders that block therapeutically relevant protein‐protein interactions.
A protein‐directed dynamic combinatorial chemistry (DCC) method, coupled to a proteomics data analysis workflow, was used to discover interface blockers of the PD‐1/PD‐L1 interaction. The S‐linked dimeric species that were significantly amplified in the protein‐templated mixture were identified, synthesized, and subjected to biophysical screening.
Background: Most cancers of the uterine cervix are squamous cell carcinomas. Although the incidence of such carcinomas of the uterine cervix has declined over time, that of cervical adenocarcinoma ...has risen in recent years. The extent to which human papillomavirus (HPV) infection and cofactors may explain this differential trend is unclear. Methods: We pooled data from eight case–control studies of cervical cancer that were conducted on three continents. A total of 167 case patients with invasive cervical adenocarcinoma (112 with adenocarcinoma and 55 with adenosquamous carcinoma) and 1881 hospital-based control subjects were included. HPV DNA was analyzed in cervical specimens with the GP5+/6+ general primer system followed by type-specific hybridization for 33 HPV genotypes. Blood samples were analyzed for chlamydial and herpes simplex virus 2 (HSV-2) serology. Multivariable unconditional logistic regression modeling was used to calculate odds ratios (ORs) with 95% confidence intervals (CIs). All tests of statistical significance were two-sided. Results: The adjusted overall odds ratio for cervical adenocarcinoma in HPV-positive women compared with HPV-negative women was 81.3 (95% CI = 42.0 to 157.1). HPV 16 and HPV 18 were the two most commonly detected HPV types in case patients and control subjects. These two types were present in 82% of the patients. Cofactors that showed clear statistically significant positive associations with cervical adenocarcinoma overall and among HPV-positive women included never schooling, poor hygiene, sexual behavior–related variables, long-term use of hormonal contraception, high parity, and HSV-2 seropositivity. Parity had a weaker association with adenocarcinoma and only among HPV-positive women. Use of an intrauterine device (IUD) had a statistically significant inverse association with risk of adenocarcinoma (for ever use of an IUD compared with never use, OR = .41 95% CI = 0.18 to 0.93). Smoking and chlamydial seropositivity were not associated with disease. Conclusions: HPV appears to be the key risk factor for cervical adenocarcinoma. HPV testing in primary screening using current mixtures of HPV types and HPV vaccination against main HPV types should reduce the incidence of this cancer worldwide.
Estimates from the year 2000 indicate that liver cancer remains the fifth most common malignancy in men and the eighth in women worldwide. The number of new cases is estimated to be 564,000 per year, ...including 398,000 in men and 166,000 in women. In high-risk countries, liver cancer can arise before the age of 20 years, whereas, in countries at low risk, liver cancer is rare before the age of 50 years. Rates of liver cancer in men are typically 2 to 4 times higher than in women. The incidence of primary liver cancer is increasing in several developed countries, including the United States, and the increase will likely continue for some decades. The trend is a result of a cohort effect related to infection with hepatitis B and C viruses, the incidence of which peaked in the 1950s to 1980s. In selected areas of some developing countries, the incidence of primary liver cancer has decreased, possibly as a result of the introduction of hepatitis B virus vaccine. The geographic variability in incidence of primary liver cancer is largely explained by the distribution and the natural history of the hepatitis B and C viruses. The attributable risk estimates for the combined effects of these infections account for well over 80% of liver cancer cases worldwide. Primary liver cancer is the first human cancer largely amenable to prevention using hepatitis B virus vaccines and screening of blood and blood products for hepatitis B and C viruses.
In cancer, proliferation of malignant cells is driven by overactivation of growth‐signalling mechanisms, such as the epidermal growth factor receptor (EGFR) pathway. Despite its therapeutic ...relevance, the EGF–EGFR interaction has remained elusive to inhibition by synthetic molecules, mostly as a result of its large size and lack of binding pockets and cavities. Designed peptides, featuring cyclic motifs and other structural constraints, have the potential to modulate such challenging protein–protein interactions (PPIs). Herein, we present the structure‐based design of a series of bicyclic constrained peptides that mimic an interface domain of EGFR and inhibit the EGF–EGFR interaction by targeting the smaller partner (i.e., EGF). This design process was guided by the integrated use of in silico methods and biophysical techniques, such as NMR spectroscopy and surface acoustic wave. The best analogues were able to reduce selectively the viability of EGFR+ human cancer cells. In addition to their efficacy, these bicyclic peptides are endowed with exceptional stability and metabolic resistance—two features that make them suitable candidates for in vivo applications.
Under the skin: Starting from a key binding domain of the epidermal growth factor receptor (EGFR), we use computational and biophysical methods to design a series of bicyclic constrained peptides—highly resistant to metabolic degradation—that disrupt the EGF–EGFR interaction and block EGFR‐dependent cancer‐cell proliferation.
Tumour suppressor p53 plays a key role in the development of cancer and has therefore been widely studied in recent decades. While it is well known that p53 is biologically active as a tetramer, the ...tetramerisation mechanism is still not completely understood. p53 is mutated in nearly 50% of cancers, and mutations can alter the oligomeric state of the protein, having an impact on the biological function of the protein and on cell fate decisions. Here, we describe the effects of a number of representative cancer-related mutations on tetramerisation domain (TD) oligomerisation defining a peptide length that permits having a folded and structured domain, thus avoiding the effect of the flanking regions and the net charges at the
- and
-terminus. These peptides have been studied under different experimental conditions. We have applied a variety of techniques, including circular dichroism (CD), native mass spectrometry (MS) and high-field solution NMR. Native MS allows us to detect the native state of complexes maintaining the peptide complexes intact in the gas phase; the secondary and quaternary structures were analysed in solution by NMR, and the oligomeric forms were assigned by diffusion NMR experiments. A significant destabilising effect and a variable monomer population were observed for all the mutants studied.
The efficient preparation of novel bioactive peptide drugs requires the availability of reliable and accessible chemical methodologies together with suitable analytical techniques for the full ...characterisation of the synthesised compounds. Herein, we describe a novel acidolytic method with application to the synthesis of cyclic and linear peptides involving benzyl-type protection. The process consists of the in situ generation of anhydrous hydrogen bromide and a trialkylsilyl bromide that acts as protic and Lewis acid reagents. This method proved to be useful to effectively remove benzyl-type protecting groups and cleave Fmoc/
Bu assembled peptides directly attached to 4-methylbenzhydrylamine (MBHA) resins with no need for using mild trifluoroacetic acid labile linkers. The novel methodology was successful in synthesising three antimicrobial peptides, including the cyclic compound polymyxin B3, dusquetide, and RR4 heptapeptide. Furthermore, electrospray mass spectrometry (ESI-MS) is successfully used for the full characterisation of both the molecular and ionic composition of the synthetic peptides.
New approaches are being developed to early detect endometrial cancer using molecular biomarkers. These approaches offer high sensitivities and specificities, representing a promising horizon to ...develop early detection strategies.
To evaluate the effectiveness and cost-effectiveness of introducing molecular testing to detect endometrial cancer in women with postmenopausal bleeding compared to the current strategy using the national healthcare service perspective.
A Markov model was developed to assess the two early detection strategies. The model predicts the number of hysterectomies, lifetime expectancy, quality-adjusted life-years, endometrial cancer prevalence and incidence, mortality from endometrial cancer and the lifetime cost of screening, diagnosis, and treatment. Strategies were compared using the incremental cost-effectiveness ratio.
The molecular strategy reduces 1.9% of the overall number of hysterectomies and the number of undetected cancer cases by 65%. Assuming a molecular test cost of 310€, the molecular strategy has an incremental cost of -32,952€ per QALY gained, being more effective and less expensive than the current strategy.
The introduction of molecular testing to diagnose endometrial cancer in women presenting postmenopausal bleeding provides more health benefit at a lower cost, and therefore has the potential to be cost-effective.
Peptides Targeting EGF Block the EGF-EGFR Interaction Guardiola, Salvador; Díaz-Lobo, Mireia; Seco, Jesús ...
Chembiochem : a European journal of chemical biology,
April 15, 2016, Letnik:
17, Številka:
8
Journal Article
Recenzirano
Epidermal growth factor receptor (EGFR) is a key target in chemotherapy. Some drugs acting on the receptor are currently in use; however, drug resistance, which causes tumour relapse, calls for the ...discovery of alternative inhibitors. Using docking and receptor hotspot mimicry, we have designed novel peptides directed at EGF, the main growth factor ligand of EGFR. An array of biophysical techniques was used to characterise the structure and interaction of these ligands with the target protein. Both design methods identified peptides able to bind EGF, and the capacity of these peptides to inhibit the interaction between EGF and EGFR was demonstrated in two in vitro systems. Based on targeting the smaller companion of a protein–protein interaction, the new approach described herein can be envisaged as a parallel drug design strategy, and our compounds represent the first in a new class of binders that could serve as complementary compounds in potential multidrug cancer therapy.
A novel EGF–EGFR targeting approach: A new class of peptide ligands against EGF has been designed by using computer‐aided docking and EGFR hotspot mimicry. Their binding to EGF was studied in detail, and their ability to disrupt the EGF–EGFR interaction was demonstrated in vitro.
In Pseudomonas aeruginosa, Ttg2D is the soluble periplasmic phospholipid-binding component of an ABC transport system thought to be involved in maintaining the asymmetry of the outer membrane. Here ...we use the crystallographic structure of Ttg2D at 2.5 Å resolution to reveal that this protein can accommodate four acyl chains. Analysis of the available structures of Ttg2D orthologs shows that they conform a new substrate-binding-protein structural cluster. Native and denaturing mass spectrometry experiments confirm that Ttg2D, produced both heterologously and homologously and isolated from the periplasm, can carry two diacyl glycerophospholipids as well as one cardiolipin. Binding is notably promiscuous, allowing the transport of various molecular species. In vitro binding assays coupled to native mass spectrometry show that binding of cardiolipin is spontaneous. Gene knockout experiments in P. aeruginosa multidrug-resistant strains reveal that the Ttg2 system is involved in low-level intrinsic resistance against certain antibiotics that use a lipid-mediated pathway to permeate through membranes.
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