Photoredox-catalysed hydroaminoalkylation of on-DNA N-arylamines.

An efficient approach to the photoredox-catalysed hydroaminoalkylation between on-DNA secondary N-substituted (hetero)arylamines and vinylarenes has been developed and explored. The methodology was examined with a broad scope of vinylarenes and secondary arylamines to establish a preferred building block profile for the process. Compatible substrates furnished the desired derivitised amine products in modest to excellent conversions and with minimal or no detectable by-products.

Role of the Wnt and GTPase pathways in breast cancer tumorigenesis and treatment.

Breast cancer (BC) is the most frequently diagnosed cancer among women in all the populations of the world. Although the BC mortality rate has declined, resistance to treatment is still a significant challenge for patient survival. Various cellular signaling pathways, such as Wnt and Rho/GTPase have been linked to the development, migration, and metastasis of BC, and also in treatment resistance mechanisms. Some studies have shown an association between two important cellular pathways, Wnt and Rho/GTPase, in cytoskeleton activation and cancer invasion. However, their involvement in BC has received little attention. This review summarizes the Wnt and Rho/GTPases signaling pathway functions, and also the crosstalk between these pathways in the progression, metastasis, and drug resistance mechanisms in BC. Considering the signaling pathways involved in BC tumorigenesis, future studies will need to investigate possible molecular interventions and new opportunities for the development of personalized strategies for BC treatment in order to improve overall outcomes.

PhOxi-Seq: Single-Nucleotide Resolution Sequencing of N2-Methylation at Guanosine in RNA by Photoredox Catalysis.

Chemical modifications regulate the fate and function of cellular RNAs. Newly developed sequencing methods have allowed a deeper understanding of the biological role of RNA modifications; however, the vast majority of post-transcriptional modifications lack a well-defined sequencing method. Here, we report a photo-oxidative sequencing (PhOxi-seq) approach for guanosine N2-methylation, a common methylation mark seen in N2-methylguanosine (m2G) and N2,N2-dimethylguanosine (m22G). Using visible light-mediated organic photoredox catalysis, m2G and m22G are chemoselectively oxidized in the presence of canonical RNA nucleosides, which results in a strong mutation signature observed during sequencing. PhOxi-seq was demonstrated on various tRNAs and rRNA to reveal N2-methylation with excellent response and markedly improved read-through at m22G sites.

Biological and pharmacological effects and nutritional impact of phytosterols: A comprehensive review.

Phytosterols (PSs), classified into plant sterols and stanols, are bioactive compounds found in foods of plant origin. PSs have been proposed to exert a wide number of pharmacological properties, including the potential to reduce total and low-density lipoprotein (LDL) cholesterol levels and thereby decreasing the risk of cardiovascular diseases. Other health-promoting effects of PSs include anti-obesity, anti-diabetic, anti-microbial, anti-inflammatory, and immunomodulatory effects. Also, anticancer effects have been strongly suggested, as phytosterol-rich diets may reduce the risk of cancer by 20%. The aim of this review is to provide a general overview of the available evidence regarding the beneficial physiological and pharmacological activities of PSs, with special emphasis on their therapeutic potential for human health and safety. Also, we will explore the factors that influence the physiologic response to PSs.

The Effect of Garlic (Allium sativum L) Supplementation on Circulating Adiponectin: a Systematic Review and Meta-Analysis of Randomized Controlled Trials.

Our aim was to conduct a systematic review and meta-analysis on randomized controlled trials (RCTs) evaluating the effect of garlic on serum adiponectin levels. We searched Scopus, Web of Science, PubMed, and Cochrane Library to databases up to January 2021. RCTs investigating the effects of garlic on serum adiponectin levels in adult participants were included. The change in serum adiponectin levels was estimated using weighted mean differences (WMD) and standard deviations (SD). The random effects model was used to provide a summary of mean estimates and their SDs. Out of 386 records, 6 trials with 8 arms treatment which enrolled 266 subjects were included. Garlic supplementation resulted in a non-significant increase in adiponectin concentrations when compared to placebo, according to the pooled data (WMD, 0.27 Hedges' g; 95% confidence interval [CI], -0.07, 0.62; p = 0.124). Greater effects on adiponectin were observed in trials with supplementation dose less than 1.5 gram per day (WMD, 0.71 Hedges' g; 95% CI, -0.01, 1.43; p = 0.600) and in trials with female subset (WMD, 0.62 Hedges' g; 95% CI, -0.96, 2.21; p = 0.441). Garlic boosts adiponectin levels in general. However, due to different target population, various units for reporting adiponectin level and few eligible studies in final analysis, more research is needed to get a firm conclusion about the influence of garlic on adiponectin levels.

Single-nucleotide resolution of N 6-adenine methylation sites in DNA and RNA by nitrite sequencing.

A single-nucleotide resolution sequencing method of N 6-adenine methylation sites in DNA and RNA is described. Using sodium nitrite under acidic conditions, chemoselective deamination of unmethylated adenines readily occurs, without competing deamination of N 6-adenine sites. The deamination of adenines results in the formation of hypoxanthine bases, which are read by polymerases and reverse transcriptases as guanine; the methylated adenine sites resist deamination and are read as adenine. The approach, when coupled with high-throughput DNA sequencing and mutational analysis, enables the identification of N 6-adenine sites in RNA and DNA within various sequence contexts.

Evolutionary Outcomes of Diversely Functionalized Aptamers Isolated from in Vitro Evolution.

Expanding the chemical diversity of aptamers remains an important thrust in the field in order to increase their functional potential. Previously, our group developed LOOPER, which enables the incorporation of up to 16 unique modifications throughout a ssDNA sequence, and applied it to the in vitro evolution of thrombin binders. As LOOPER-derived highly modified nucleic acids polymers are governed by two interrelated evolutionary variables, namely, functional modifications and sequence, the evolution of this polymer contrasts with that of canonical DNA. Herein we provide in-depth analysis of the evolution, including structure-activity relationships, mapping of evolutionary pressures on the library, and analysis of plausible evolutionary pathways that resulted in the first LOOPER-derived aptamer, TBL1. A detailed picture of how TBL1 interacts with thrombin and how it may mimic known peptide binders of thrombin is also proposed. Structural modeling and folding studies afford insights into how the aptamer displays critical modifications and also how modifications enhance the structural stability of the aptamer. A discussion of benefits and potential limitations of LOOPER during in vitro evolution is provided, which will serve to guide future evolutions of this highly modified class of aptamers.

Influence of Linker Length on Ligase-Catalyzed Oligonucleotide Polymerization.

Ligase-catalyzed oligonucleotide polymerization (LOOPER) that enables the sequence-defined generation of DNA with up to 16 different modifications has recently been developed. This approach was used to develop new classes of diversely modified DNA aptamers for molecular recognition through in vitro evolution. The modifications in LOOPER are appended by use of a long hexane-1,6-diamine linker, which could negatively impact binding thermodynamics. Here we explore the incorporation of modifications with the aid of shorter linkers and the use of commercially available phosphoramidites and assess their efficiency and fidelity of incorporation. We observed that shorter linkers are less tolerated during LOOPER, with very short linkers providing high levels of error and sequence bias. An ethane-1,2-diamine linker was found to be optimal in terms of yield, efficiency, and bias; however, codon adjustment was necessary. This shorter-linker anticodon set for LOOPER should prove valuable in exploring the impact of diverse chemical modifications on the molecular function of DNA.

Mechanism-based candidate inhibitors of uridine diphosphate galactopyranose mutase (UGM).

Uridine diphosphate-galactopyranose mutase (UGM), an enzyme found in many eukaryotic and prokaryotic human pathogens, catalyzes the interconversion of UDP-galactopyranose (UDP-Galp) and UDP-galactofuranose (UDP-Galf), the latter being used as the biosynthetic precursor of the galactofuranose polymer portion of the mycobacterium cell wall. We report here the synthesis of a sulfonium and selenonium ion with an appended polyhydroxylated side chain. These compounds were designed as transition state mimics of the UGM-catalyzed reaction, where the head groups carrying a permanent positive charge were designed to mimic both the shape and positive charge of the proposed galactopyranosyl cation-like transition state. An HPLC-based UGM inhibition assay indicated that the compounds inhibited about 25% of UGM activity at 500 µM concentration.