Multifaceted roles of Meg3 in cellular senescence and atherosclerosis.

BACKGROUND AND AIMS: Long noncoding RNAs are involved in the pathogenesis of atherosclerosis. As long noncoding RNAs maternally expressed gene 3 (Meg3) prevents cellular senescence of hepatic vascular endothelium and obesity-induced insulin resistance, we decided to examine its role in cellular senescence and atherosclerosis. METHODS AND RESULTS: By analyzing our data and human and mouse data from the Gene Expression Omnibus database, we found that Meg3 expression was reduced in humans and mice with cardiovascular disease, indicating its potential role in atherosclerosis. In Ldlr-/- mice fed a Western diet for 12 weeks, Meg3 silencing by chemically modified antisense oligonucleotides attenuated the formation of atherosclerotic lesions by 34.9% and 20.1% in male and female mice, respectively, revealed by en-face Oil Red O staining, which did not correlate with changes in plasma lipid profiles. Real-time quantitative PCR analysis of cellular senescence markers p21 and p16 revealed that Meg3 deficiency aggravates hepatic cellular senescence but not cellular senescence at aortic roots. Human Meg3 transgenic mice were generated to examine the role of Meg3 gain-of-function in the development of atherosclerosis induced by PCSK9 overexpression. Meg3 overexpression promotes atherosclerotic lesion formation by 29.2% in Meg3 knock-in mice independent of its effects on lipid profiles. Meg3 overexpression inhibits hepatic cellular senescence, while it promotes aortic cellular senescence likely by impairing mitochondrial function and delaying cell cycle progression. CONCLUSIONS: Our data demonstrate that Meg3 promotes the formation of atherosclerotic lesions independent of its effects on plasma lipid profiles. In addition, Meg3 regulates cellular senescence in a tissue-specific manner during atherosclerosis. Thus, we demonstrated that Meg3 has multifaceted roles in cellular senescence and atherosclerosis.

Synthesis and Anti-Pancreatic Cancer Activity Studies of Novel 3-Amino-2-hydroxybenzofused 2-Phospha-γ-lactones.

A series of 3-amino-2-hydroxybenzofused 2-phosphalactones (4a-l) has been synthesized from the Kabachnik-Fields reaction via a facile route from a one-pot three-component reaction of diphenylphosphite with various 2-hydroxybenzaldehyes and heterocyclic amines in a new way of expansion. The in vitro anti-cell proliferation studies by MTT assay have revealed them as potential Panc-1, Miapaca-2, and BxPC-3 pancreatic cell growth inhibitors, and the same is supported by molecular docking, QSAR, and ADMET studies. The MTT assay of their SAHA derivatives against the same cell lines evidenced them as potential HDAC inhibitors and identified 4a, 4b, and 4k substituted with 1,3-thiazol, 1,3,4-thiadiazol, and 5-sulfanyl-1,3,4-thiadiazol moieties on phenyl and diethylamino phenyl rings as potential ones. Additionally, the flow cytometric analyses of 4a, 4b, and 4k against BxPC-3 cells revealed compound 4k as a lead compound that arrests the S phase cell cycle growth at low micromolar concentrations. The ADMET properties have ascertained their inherent pharmacokinetic potentiality, and the wholesome results prompted us to report it as the first study on anti-pancreatic cancer activity of cyclic α-aminophosphonates. Ultimately, this study serves as a good contribution to update the existing knowledge on the anticancer organophosphorus heterocyclic compounds and elevates the scope for generation of new anticancer drugs. Further, the studies like QSAR, drug properties, toxicity risks, and bioactivity scores predicted for them have ascertained the synthesized compounds as newer and potential drug candidates. Hence, this study had augmented the array of α-aminophosphonates by adding a new collection of 3-amino-2-hydroxybenzofused 2-phosphalactones, a class of cyclic α-aminophosphonates, to it, which proved them as potential anti-pancreatic cancer agents.

Biogenesis of silver nanoparticles using endophytic fungus Pestalotiopsis microspora and evaluation of their antioxidant and anticancer activities.

An endophytic fungal strain isolated from the leaves of Gymnema sylvestre was identified as Pestalotiopsis microspora VJ1/VS1 based on nucleotide sequencing of internal transcribed spacer region (ITS 1-5.8S-ITS 2) of 18S rRNA gene (NCBI accession number KX213894). In this study, an efficient and ecofriendly approach has been reported for the synthesis of silver nanoparticles (AgNPs) using aqueous culture filtrate of P. microspora. Ultraviolet-visible analysis confirmed the synthesis of AgNPs by showing characteristic absorption peak at 435 nm. Fourier transform infrared spectroscopy analysis revealed the presence of phenolic compounds and proteins in the fungal filtrate, which are plausibly involved in the biosynthesis and capping of AgNPs. Transmission electron microscopy (TEM) showed that the AgNPs were spherical in shape of 2-10 nm in size. Selected area electron diffraction and X-ray diffraction studies determined the crystalline nature of AgNPs with face-centered cubic (FCC) lattice phase. Dynamic light scattering analysis showed that the biosynthesized AgNPs possess high negative zeta potential value of -35.7 mV. Biosynthesized AgNPs were proved to be potential antioxidants by showing effective radical scavenging activity against 2,2'-diphenyl-1-picrylhydrazyl and H2O2 radicals with IC50 values of 76.95±2.96 and 94.95±2.18 µg/mL, respectively. The biosynthesized AgNPs exhibited significant cytotoxic effects against B16F10 (mouse melanoma, IC50 =26.43±3.41 µg/mL), SKOV3 (human ovarian carcinoma, IC50 =16.24±2.48 µg/mL), A549 (human lung adenocarcinoma, IC50 =39.83±3.74 µg/mL), and PC3 (human prostate carcinoma, IC50 =27.71±2.89 µg/mL) cells. The biosynthesized AgNPs were found to be biocompatible toward normal cells (Chinese hamster ovary cell line, IC50 =438.53±4.2 µg/mL). Cytological observations on most susceptible SKOV3 cells revealed concentration-dependent apoptotic changes that include cell membrane blebbing, cell shrinkage, pyknotic nuclei, karyorrhexis followed by destructive fragmentation of nuclei. The results together in this study strongly provided a base for the development of potential and versatile biomedical applications of biosynthesized AgNPs in the near future.

Development of novel HER2 inhibitors against gastric cancer derived from flavonoid source of Syzygium alternifolium through molecular dynamics and pharmacophore-based screening.

Continuous usage of synthetic chemotherapeutic drugs causes adverse effects, which prompted for the development of alternative therapeutics for gastric cancer from natural source. This study was carried out with a specific aim to screen gastroprotective compounds from the fruits of Syzygium alternifolium (Myrtaceae). Three flavonoids, namely, 1) 5-hydroxy-7,4'-dimethoxy-6,8-di-C-methylflavone, 2) kaempferol-3-O-ß-d-glucopyranoside, and 3) kaempferol-3-O-α-l-rhamnopyranoside were isolated from the above medicinal plant by employing silica gel column chromatography and are characterized by NMR techniques. Antigastric cancer activity of these flavonoids was examined on AGS cell lines followed by cell cycle progression assay. In addition, pharmacophore-based screening and molecular dynamics of protein-ligand complex were carried out to identify potent scaffolds. The results showed that compounds 2 and 3 exhibited significant cytotoxic effect, whereas compound 1 showed moderate effect on AGS cells by inhibiting G2/M phase of cell cycle. Molecular docking analysis revealed that compound 2 has higher binding energies on human growth factor receptor-2 (HER2). The constructed pharmacophore models reveal that the compounds have more number of H-bond Acc/Don features which contribute to the inhibition of HER2 activity. By selecting these features, 34 hits were retrieved using the query compound 2. Molecular dynamic simulations (MDS) of protein-ligand complexes demonstrated conspicuous inhibition of HER2 as evidenced by dynamic trajectory analysis. Based on these results, the compound ZINC67903192 was identified as promising HER2 inhibitor against gastric cancer. The present work provides a basis for the discovery a new class of scaffolds from natural products for gastric carcinoma.