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AMP-activated protein kinase (AMPK) serves as an energy sensor and is considered a promising drug target for treatment of type II diabetes and obesity. A previous report has shown that mammalian AMPK ␣1 catalytic subunit including autoinhibitory domain was inactive. To test the hypothesis that small molecules can activate AMPK through antagonizing the autoinhibition in ␣ subunits, we screened a chemical library with inactive human ␣1 394 (␣1, residues 1-394) and found a novel small-molecule activator, PT1, which dose-dependently activated AMPK ␣1 394 , ␣1 335 , ␣2 398 , and even heterotrimer ␣1␤1␥1. Based on PT1-docked AMPK ␣1 subunit structure model and different mutations, we found PT1 might interact with Glu-96 and Lys-156 residues near the autoinhibitory domain and directly relieve autoinhibition. Further studies using L6 myotubes showed that the phosphorylation of AMPK and its downstream substrate, acetyl-CoA carboxylase, were dose-dependently and time-dependently increased by PT1 without an increase in cellular AMP:ATP ratio. Moreover, in HeLa cells deficient in LKB1, PT1 enhanced AMPK phosphorylation, which can be inhibited by the calcium/calmodulin-dependent protein kinase kinases inhibitor STO-609 and AMPK inhibitor compound C. PT1 also lowered hepatic lipid content in a dose-dependent manner through AMPK activation in HepG2 cells, and this effect was diminished by compound C. Taken together, these data indicate that this small-molecule activator may directly activate AMPK via antagonizing the autoinhibition in vitro and in cells. This compound highlights the effort to discover novel AMPK activators and can be a useful tool for elucidating the mechanism responsible for conformational change and autoinhibitory regulation of AMPK.The AMP-activated protein kinase (AMPK) 3 is a highly conserved serine/threonine protein kinase that is widely expressed in higher eukaryotes, yeast, and plants and plays a unique and central role in the responses of cells to metabolic stresses such as nutrient starvation, heat shock, ischemia/hypoxia, and vigorous muscular exercise by depleting cellular ATP and elevating AMP levels (1, 2). Once activated, AMPK prevents depletion of ATP by increasing the rate of ATP generation, triggering changes in the rates of glucose transport, fatty acid oxidation, lipogenesis, sterol synthesis, and gluconeogenesis through direct regulation of key metabolic enzymes and transcriptional control of specific genes (1-4). There is mounting evidence of the involvement of AMPK in human physiological and pathological processes, especially type 2 diabetes and obesity. Previous studies indicate that several of the beneficial effects of rosiglitazone and metformin, two widely used antidiabetic drugs, are mediated by indirect activation of AMPK, suggesting the potential role of the AMPK pathway in the treatment of type 2 diabetes (5, 7). Two adipocyte-derived hormones, leptin and adiponectin, stimulate fatty acid oxidation and glucose uptake in peripheral tissues such as skeletal muscle and liver, whic...

The YAP-TEAD protein-protein interaction (PPI) mediates the oncogenic function of YAP, and inhibitors of this PPI have potential usage in treatment of YAP-involved cancers. Here we report the design and synthesis of potent cyclic peptide inhibitors of the YAP-TEAD interaction. A truncation study of YAP interface 3 peptide identified YAP(84-100) as a weak peptide inhibitor (IC50 = 37 μM), and an alanine scan revealed a beneficial mutation, D94A. Subsequent replacement of a native cation-π interaction with an optimized disulfide bridge for conformational constraint and synergistic effect between macrocyclization and modification at positions 91 and 93 greatly boosted inhibitory activity. Peptide 17 was identified with an IC50 of 25 nM, and the binding affinity (K d = 15 nM) of this 17mer peptide to TEAD1 proved to be stronger than YAP(50-171) (K d = 40 nM).

Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR TKIs) have been first-line therapy in the treatment of non-small cell lung cancer (NSCLC) harboring EGFR sensitive mutations. Progression inevitably happens after 10–14 months of first- or second-generation EGFR TKIs treatment for acquired resistance. Owing to the successful identification of EGFR T790M, third-generation EGFR TKIs such as osimertinib were developed to target such resistance mutation. Nowadays, osimertinib has shown its efficacy both in first-line and second-line after resistance to previous generations of TKI treatment of EGFR-mutant NSCLC. However, drug resistance also emerges on third-generation EGFR TKIs. Multiple mechanisms of acquired resistance have been identified, and some novel strategies were reported to overcome third-generation TKI resistance. Immune checkpoint inhibitors (ICIs) have dramatically changed the prognosis of selected patients. For patients with EGFR-addicted metastatic NSCLC, ICIs have also revealed a potential role. In this review, we will take stock of mechanisms of acquired resistance to third-generation TKIs and discuss current challenges and future perspectives in clinical practice.

Flaxseed oil is rich in linolenic acid, and being accepted in diet by more and more people. The characteristics of flaxseed oil from two different varieties, namely fibre-flax seed and oil-flax seed, were evaluated. It was shown that fatty acids of flaxseed oil were mainly constituted by linolenic, oleic, linoleic, stearic, and palmitic acids, and the oil-flax seed oil contained more linolenic acid (58.03%) compared with the fibre-flax seed oil (47.37%). The fibre-flax seed oil showed a higher absorbance at 290-800 nm. Thermogravimetric curves showed that the oil-flax seed oil was more stable than the fibre-flax seed oil. Thermal profiles indicated that the fibre-flax seed oil had higher melting peak temperature and larger enthalpy. Rheological studies indicated that the apparent viscosity of the fibre-flax seed oil was higher than that of the oil-flax seed oil. It can be concluded that the oil-flax seed oil is better than the fibre-flax seed oil in terms of edibility.

Herein we report the identification of a novel class of HDAC6 and HDAC8 selective inhibitors through a unique chemistry and phenotypic screening strategy. Tetrahydroisoquinoline 12 was identified as a potent HDAC6 and HDAC8 dual inhibitor from a focused library through cellular tubulin acetylation and p21 induction screening assays. Scaffold hopping from 12 led to the discovery of an aminotetralin class of HDAC inhibitors. In particular, the 3-R stereoisomer 32 showed highly potent inhibition against HDAC6 and HDAC8 with IC50 values of 50 and 80 nM, respectively. Treatment of neuroblastoma BE(2)C cells with 32 resulted in elevated levels of acetylated tubulin, TrkA, and neurite outgrowth with only marginal effects on p21 induction and histone H3 acetylation. Consistent with its weak enzymatic inhibition of HDAC1, 32 showed significantly less cytotoxicity than SAHA and moderately inhibited the growth of myeloma NCI-H929 and OPM-2 cells.

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