A hairpin-mediated nicking enzymatic signal amplification for nucleic acids detection.

A novel signal amplification to detect nucleic acid, called hairpin-mediated nicking enzymatic signal amplification (HNESA), is developed. This method overcomes the limitation of conventional nicking enzymatic signal amplification (NESA) that the target must contain the nicking endonuclease recognition site by using a hairpin probe containing the nicking endonuclease recognition site as an intermediary. Nucleic acid with any sequence can be amplified by HNESA which substantially improves the substrate-scope of traditional NESA. HNESA could detect nucleic acids (ssDNA and RNA) with a detection limit of 8.3 pM at 55 °C. As low as 68 fM could also be detected by integrating HNESA and strand-displacement amplification (SDA). More importantly, HNESA is quite efficient in distinguish single base mismatched sequences. HNESA has potential application for nucleic acid detection in complex biological samples. Therefore, HNESA with high sensitivity and ultrahigh selectivity, should be a promising tool for nucleic acid research, especially for single nucleotide polymorphism (SNP) detection.

Inhibitory mechanism of muscone in liver cancer involves the induction of apoptosis and autophagy.

Traditionally, musk has been used as an analgesic to treat pain associated with cancer. Hepatocellular carcinoma (HCC) is an aggressive tumor; however, patients with liver cancer that received musk were reported to live longer and have a higher quality of life. Thus, the present study aimed to investigate whether muscone, a macrocyclic compound of musk, demonstrated potential as an anti­liver cancer drug for the non­surgical treatment of advanced liver cancer. Briefly, liver cancer cells were treated with muscone and the rates of cellular apoptosis and autophagy were investigated using staining techniques and western blotting. The underlying molecular mechanisms of muscone were evaluated using high­throughput sequencing and the in vitro effects of muscone were subsequently validated in vivo using a nude mouse model. Muscone increased the rates of apoptosis and autophagy in liver cancer cells; the increase in cellular apoptosis was observed to occur through endoplasmic reticulum stress responses, whereas muscone­induced autophagy was closely associated with the AMP kinase/mTOR complex 1 signaling pathway. These findings were verified in vivo. Notably, sestrin­2 expression levels were also significantly decreased in liver cancer tissues compared with paracancerous tissues. In conclusion, the present study suggests that muscone demonstrates potential as an anticancer drug, and the findings of the present study provide the basis for the development of effective anticancer drugs derived from natural compounds.

LncRNA GABPB1-AS1 and GABPB1 regulate oxidative stress during erastin-induced ferroptosis in HepG2 hepatocellular carcinoma cells.

Ferroptosis is a non-apoptotic, iron-dependent oxidative form of cell death that is specifically induced by erastin in RAS mutant cancer cells. Ferroptotic cell death is the result of membrane lipid peroxide damage caused by the accumulation of hydroxyl radicals derived from H2O2 by the Fenton reaction. Peroxidases are key cellular antioxidant enzymes that block such damaging processes. Few studies have examined the roles of long non-coding RNAs (lncRNAs) in the regulation of cellular oxidative stress, especially in ferroptosis. Here, we demonstrated that erastin upregulated the lncRNA GABPB1-AS1, which downregulated GABPB1 protein levels by blocking GABPB1 translation, leading to the downregulation of the gene encoding Peroxiredoxin-5 (PRDX5) peroxidase and the eventual suppression of the cellular antioxidant capacity. Such effects critically inhibited the cellular antioxidant capacity and cell viability. Additionally, high expression levels of GABPB1 were correlated with poor prognosis of hepatocellular carcinoma (HCC) Patients, while high GABPB1-AS1 levels in HCC patients correlated with improved overall survival. Collectively, these data demonstrate a mechanistic link between GABPB1 and its antisense lncRNA GABPB1-AS1 in erastin-induced ferroptosis and establish GABPB1 and GABPB1-AS1 as attractive therapeutic targets for HCC.

A long noncoding RNA distributed in both nucleus and cytoplasm operates in the PYCARD-regulated apoptosis by coordinating the epigenetic and translational regulation.

Long noncoding RNAs (lncRNAs) participate in various biological processes such as apoptosis. The function of lncRNAs is closely correlated with their localization within the cell. While regulatory potential of many lncRNAs has been revealed at specific subcellular location, the biological significance of discrete distribution of an lncRNA in different cellular compartments remains largely unexplored. Here, we identified an lncRNA antisense to the pro-apoptotic gene PYCARD, named PYCARD-AS1, which exhibits a dual nuclear and cytoplasmic distribution and is required for the PYCARD silencing in breast cancer cells. The PYCARD-regulated apoptosis is controlled by PYCARD-AS1; moreover, PYCARD-AS1 regulates apoptosis in a PYCARD-dependent manner, indicating that PYCARD is a critical downstream target of PYCARD-AS1. Mechanistically, PYCARD-AS1 can localize to the PYCARD promoter, where it facilitates DNA methylation and H3K9me2 modification by recruiting the chromatin-suppressor proteins DNMT1 and G9a. Moreover, PYCARD-AS1 and PYCARD mRNA can interact with each other via their 5' overlapping region, leading to inhibition of ribosome assembly in the cytoplasm for PYCARD translation. This study reveals a mechanism whereby an lncRNA works at different cellular compartments to regulate the pro-apoptotic gene PYCARD at both the epigenetic and translational levels, contributing to the PYCARD-regulated apoptosis, and also sheds new light on the role of discretely distributed lncRNAs in diverse biological processes.

Antibacterial coordination polymer hydrogels composed of silver(i)-PEGylated bisimidazolylbenzyl alcohol.

Herein, antibacterial coordination polymer hydrogels were conveniently fabricated in water via coordination between silver nitrate and PEGylated bisimidazolylbenzyl alcohol (1a-c). These coordination polymer hydrogels exhibit much better antibacterial activity than silver nitrate against both Gram-negative and Gram-positive pathogens including multidrug-resistant pathogens. The coordination polymer Ag/1c with a long PEG chain (PEG1000) was demonstrated to be the most effective antibacterial material, and its minimum inhibition concentrations (MICs) could be as low as 15.2 times for common Staphylococcus aureus and 4.8 times for methicillin-resistant Staphylococcus aureus over that of silver nitrate. With improved antibacterial performance, easy preparation method, improved stability, sustained releasability, outstanding ductility and low cytotoxicity, the as-prepared coordination polymer hydrogels should find various potential applications such as in clinical burn and wound dressings, biofilms, bioadhesives, and coatings of biomedical materials.