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Human mutT homolog 1(MTH1), the oxidized dNTP pool sanitizer enzyme, has been reported to be highly expressed in various malignant tumors. However, the oncogenic role of MTH1 in gastric cancer remains to be determined. In the current study, we found that MTH1 was overexpressed in human gastric cancer tissues and cells. Using an in vitro MTH1 inhibitor screening system, the compounds available in our laboratory were screened and the small molecules containing 5-cyano-6-phenylpyrimidine structure were firstly found to show potently and specifically inhibitory effect on MTH1, especially compound MI-743 with IC 50  = 91.44 ± 1.45 nM. Both molecular docking and target engagement experiments proved that MI-743 can directly bind to MTH1. Moreover, MI-743 could not only inhibit cell proliferation in up to 16 cancer cell lines, especially gastric cancer cells HGC-27 and MGC-803, but also significantly induce MTH1-related 8-oxo-dG accumulation and DNA damage. Furthermore, the growth of xenograft tumours derived by injection of MGC-803 cells in nude mice was also significantly inhibited by MI-743 treatment. Importantly, MTH1 knockdown by siRNA in those two gastric cancer cells exhibited the similar findings. Our findings indicate that MTH1 is highly expressed in human gastric cancer tissues and cell lines. Small molecule MI-743 with 5-cyano-6-phenylpyrimidine structure may serve as a novel lead compound targeting the overexpressed MTH1 for gastric cancer treatment.

Photobiomodulation therapy (PBMT) has been demonstrated as regulating osteoblast proliferation. MicroRNAs (miRNAs) are involved in various pathophysiologic processes in osteoblast, but the role of miRNAs in the PBMT-based promotion of osteoblast proliferation remains unclear. This study aimed to investigate the effects of PBMT treatment (3.75 J/cm 2 ) on mouse pre-osteoblast cell line MC3T3-E1 proliferation and apoptosis via the miR-503/Wnt3a pathway; meanwhile, detect the expressions of miR-503 and Wnt3a after PBMT treatment and the role of miR-503 in regulating Wnt signaling molecules Wnt3a, β-catenin, Runx2, apoptotic proteins caspase-3, and Bcl-2 in vitro. The PBMT parameters were as follows: 808 nm continuous wavelength, 0.401 W output power, 0.042 W/cm 2 power density, 9.6 cm 2 spot size, 36 J energy, 3.75 J/cm 2 energy density, 90 s irradiation for three times per 12 h, 14.5 cm distance of the laser source and the angle of divergence of the laser beam was 7°. In our present study, the target relationship was predicted and verified by bioinformatics analysis and luciferase reporter assays. Gene mRNA and protein expressions were examined by qPCR and western blot analysis. The MTT method was used to evaluate the effect of miR-503 on MC3T3-E1 cells proliferation. And cell apoptosis was examined by flow cytometry. The results showed that PBMT treatment reduced the expression of miR-503 and increased the level of Wnt3a (p < 0.01). Bioinformatics analysis and luciferase reporter assays revealed that Wnt3a was a target of miR-503, and Wnt3a was regulated by miR-503. Furthermore, miR-503 was found to functionally inhibit proliferation and promote apoptosis (p < 0.01). And during this process, Wnt3a, β-catenin, Runx2, and Bcl-2 expressions were significantly inhibited (p < 0.01); however, caspase-3 level was upregulated (p < 0.01). These results suggest that miR-503 plays a role in osteoblast proliferation and apoptosis in response to PBMT, which is potentially amenable to therapeutic manipulation for clinical application.

To evaluate the alleviating action of exogenous N-acyl-homoserine lactones (AHLs) on NaCl toxicity, morphological, physiological and proteomic changes were investigated in Arabidopsis thaliana seedlings. Salinity stress decreased growth parameters, increased malondialdehyde (MDA) contents and antioxidant enzymes such as superoxide dismutase (SOD), guaiacol peroxidase (POD) and catalase activities. Application of lower concentration of AHL had a relieving effect on Arabidopsis seedlings under salinity stress which dramatically decreased MDA content, and increased growth parameters as well as SOD and POD activities. Total proteins were extracted from the control, NaCl-, AHL- and NaCl + AHL-treated seedlings and were separated using two-dimensional gel electrophoresis. A total of 127 protein spots showed different expression compared with the control. Mass spectrometry analysis allowed the identification of 97 proteins involved in multiple pathways, i.e. defense/stress/detoxification, photosynthesis, protein metabolism, signal transduction, transcription, cell wall biogenesis, metabolisms of carbon, lipid, energy, sulfur, nucleotide and sugar. These results suggest that defense/stress response, metabolism and energy, signal transduction and regulation, protein metabolism and transcription-related proteins may be particularly subjected to regulation in salt stressed Arabidopsis seedlings, when treated with AHL and that this regulation lead to improved salt tolerance and plant growth. Overall, this study provides insight to the effect of AHL on salinity stress for the first time, and also sheds light on overview of the molecular mechanism of AHL-regulated plant growth promotion and salt resistance., (© 2016 Scandinavian Plant Physiology Society.)

The mechanism of interactions between a flavonoid glycoside (linarin) and 6 flavonoids with various hydroxyl and methoxyl substituents (luteolin, apigenin, acacetin, tricin, 5,3',4'-trihydroxy-6,7-dimethoxyflavone, and 5,7,4'-trihydroxy-6,3',5'-trimethoxyflavone) and bovine serum albumin (BSA) were investigated by multi-spectroscopy, molecular docking, and quadrupole (Q)-time of flight (TOF) high resolution (HR) mass spectrometry (MS). Fluorescence spectra and molecular docking predicted that each of the flavonoids had only one probable binding site inside the hydrophobic cleft of BSA. The binding constants appeared to correlate positively with the number of hydroxyl groups, and negatively with the number of methoxyl groups. In addition, hydroxyls on ring B bound more easily with BSA than those on ring A. The change in conformation of BSA after binding suggested that the quenching mechanism was static quenching combined with nonradiative energy transfer. The results of Q-TOF HR-MS were consistent with fluorescence quenching and molecular docking., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Main Conclusion: Phosphorylation and dephosphorylation events were initiated in wheat scab resistance. The putative FHB-responsive phosphoproteins are mainly involved in three functional groups and contain at least one tyrosine, serine, or threonine phosphorylation site. Fusarium head blight (FHB), caused by Fusarium graminearum, is a severe disease in wheat. Protein phosphorylation plays an important role in plant-pathogen interactions, however, a global analysis of protein phosphorylation in response to FHB infection remains to be explored. To study the effect of FHB on the phosphorylation state of wheat proteins, proteins extracted from spikes of a resistant wheat cultivar after 6 h of inoculation with F. graminearum or sterile H2O were separated by two-dimensional gel electrophoresis, and then the immunodetection of putative phosphoproteins was conducted by Western blotting using specific anti-phosphotyrosine antibody, anti-phosphothreonine antibody and anti-phosphoserine antibody. A total of 35 phosphorylated signals was detected and protein identities of 28 spots were determined. Functional categorization showed that the putative FHB-responsive phosphoproteins were mainly involved in defense/stress response, signal transduction, and metabolism. The phosphorylation status of proteins associated with signaling pathways mediated by salicylic acid, calcium ions, small GTPase, as well as with detoxification, reactive oxygen species scavenging, antimicrobial compound synthesis, and cell wall fortification was regulated in wheat spikes in response to F. graminearum infection. The present study reveals dynamics of wheat phosphoproteome in response to F. graminearum infection and suggests an important role of protein Ser/Thr/Tyr phosphorylation in fundamental mechanisms of wheat scab resistance.

S phase kinase-associated protein 2 (Skp2) has been shown to be required for spontaneous tumor development that occurs in the retinoblastoma protein (pRb) deficient mice. Here we have demonstrated that flavokawain A (FKA), a novel chalcone from the kava plant, selectively inhibited the growth of pRb deficient cell lines and resulted in a proteasome-dependent and ubiquitination-mediated Skp2 degradation. Degradation of Skp2 by FKA was found to be involved in a functional Cullin1, but independent of Cdh1 expression. Further studies have demonstrated that FKA docked into the ATP binding pocket of the precursor cell-expressed developmentally down-regulated 8 (NEDD8)-activating enzyme (NAE) complex, inhibited NEDD8 conjugations to both Cullin1 and Ubc12 in PC3 cells and Ubc12 NEDDylation in an in vitro assay. Finally, dietary feeding of the autochthonous transgenic adenocarcinoma of the mouse prostate (TRAMP) mice with FKA inhibited the formation of high-grade prostatic intra-epithelial neoplasia lesions (HG-PIN) and prostate adenocarcinomas, reduced the tumor burden and completely abolished distant organ metastasis. Immunohistochemistry studies revealed that dietary FKA feeding resulted in marked anti-proliferative and apoptotic effects via down-regulation of Skp2 and NEDD8 and up-regulation of p27/Kip1 in the prostate of TRAMP mice. Our findings therefore provide evidence that FKA is a promising NEDDylation inhibitor for targeting Skp2 degradation in prostate cancer prevention and treatment.

When treated with 17β-estradiol, female ACI rats (Rattus norvegicus) rapidly develop mammary cancers that share multiple phenotypes with luminal breast cancers. Seven distinct quantitative trait loci that harbor genetic determinants of susceptibility to 17β-estradiol-induced mammary cancer have been mapped in reciprocal intercrosses between susceptible ACI rats and resistant Brown Norway (BN) rats. A panel of unique congenic rat strains has now been generated and characterized to confirm the existence of these quantitative trait loci, designated Emca3 through Emca9, and to quantify their individual effects on susceptibility to 17β-estradiol-induced mammary cancer. Each congenic strain carries BN alleles spanning an individual Emca locus, introgressed onto the ACI genetic background. Data presented herein indicate that BN alleles at Emca3, Emca4, Emca5, Emca6, and Emca9 reduce susceptibility to 17β-estradiol-induced mammary cancer, whereas BN alleles at Emca7 increase susceptibility, thereby confirming the previous interval mapping data. All of these Emca loci are orthologous to regions of the human genome that have been demonstrated in genome-wide association studies to harbor genetic variants that influence breast cancer risk. Moreover, four of the Emca loci are orthologous to loci in humans that have been associated with mammographic breast density, a biomarker of breast cancer risk. This study further establishes the relevance of the ACI and derived congenic rat models of 17β-estradiol-induced mammary cancer for defining the genetic bases of breast cancer susceptibility and elucidating the mechanisms through which 17β-estradiol contributes to breast cancer development., (Copyright © 2014 Colletti II et al.)

The ability of cells of the human monocyte/macrophage lineage to host HIV-1 replication while resisting cell death is believed to significantly contribute to their ability to serve as a reservoir for viral replication in the host. Although macrophages are generally resistant to apoptosis, interruption of anti-apoptotic pathways can render them susceptible to apoptosis. Here we report that HIV-1(BAL )infection of primary human monocyte-derived macrophages (MDM) upregulates the mRNA and protein levels of the anti-apoptic gene, Bcl-2. Furthermore, this upregulation can be quantitatively mimicked by treating MDM with soluble HIV-1 Tat-86 protein. These results suggest that in infecting cells of the monocyte/macrophage lineage, HIV-1 may be benefiting from additional protection against apoptosis caused by specific upregulation of cellular anti-apoptotic genes., (Copyright 2002 National Science Council, ROC and S. Karger AG, Basel)