Squamocin modulates histone H3 phosphorylation levels and induces G1 phase arrest and apoptosis in cancer cells

<p>Abstract</p> <p>Background</p> <p>Histone modifications in tumorigenesis are increasingly recognized as important epigenetic factors leading to cancer. Increased phosphorylation levels of histone H3 as a result of aurora B and pMSK1 overexpression were observed in various tumors. We selected <it>aurora B </it>and <it>MSK1 </it>as representatives for testing various compounds and drugs, and found that squamocin, a bis-tetrahydrofuran annonaceous acetogenin, exerted a potent effect on histone H3 phosphorylation.</p> <p>Methods</p> <p>GBM8401, Huh-7, and SW620 cells were incubated with 15, 30, and 60 μM squamocin for 24 h. The expressions of mRNA and proteins were analyzed by qRT-PCR and Western blotting, respectively. The cell viability was determined by an MTT assay. Cell cycle distribution and apoptotic cells were analyzed by flow cytometry.</p> <p>Results</p> <p>Our results showed that squamocin inhibited the proliferation of GBM8401, Huh-7, and SW620 cells, arrested the cell cycle at the G₁phase, and activated both intrinsic and extrinsic pathways to apoptosis. In addition, we demonstrated that squamocin had the ability to modulate the phosphorylation levels of H3S10 (H3S10p) and H3S28 (H3S28p) in association with the downregulation of aurora B and pMSK1 expressions.</p> <p>Conclusions</p> <p>This study is the first to show that squamocin affects epigenetic alterations by modulating histone H3 phosphorylation at S10 and S28, providing a novel view of the antitumor mechanism of squamocin.</p

A Verifiable Multi-authority Secret Election Allowing Abstention From Voting

In this paper, we propose a robust and verifiable multi-authority secret voting scheme which meets the requirements of large-scale general elections. This scheme uses a uniquely blind threshold signature scheme to get blind threshold electronic votes such that any voter can abstain from voting after the registration phase. It also uses the threshold cryptosystem to guarantee fairness among the candidates ’ campaigns and to provide a mechanism for ensuring that any voter can make an open objection to the tally if his vote has not been published. In this scheme, the computations among voters are independent and voters only have to send an anonymous message to the counter after the registration phase. This scheme preserves the privacy of a voter from the counter, administrators, scrutineers and other voters. Completeness, robustness and verifiability of the voting process are ensured and hence no one can produce a false tally or corrupt or disrupt the election

Nitrite Activation to Nitric Oxide via One-fold Protonation of Iron(II)‑<i>O</i>,<i>O</i>‑nitrito Complex: Relevance to the Nitrite Reductase Activity of Deoxyhemoglobin and Deoxyhemerythrin

The reversible transformations [(Bim)₃Fe­(κ²-O₂N)]­[BF₄] (<b>3</b>) ⇌ [(Bim)₃Fe­(NO)­(κ¹-ONO)]­[BF₄]₂ (<b>4</b>) were demonstrated and characterized. Transformation of <i>O</i>,<i>O</i>-nitrito-containing complex <b>3</b> into [(Bim)₃Fe­(μ-O)­(μ-OAc)­Fe­(Bim)₃]³⁺ (<b>5</b>) along with the release of NO and H₂O triggered by 1 equiv of AcOH implicates that nitrite-to-nitric oxide conversion occurs, in contrast to two protons needed to trigger nitrite reduction producing NO observed in the protonation of [Fe^II-nitro] complexes