Knockdown of the SELENOK gene induces ferroptosis in cervical cancer cells.

Selenoprotein K (SELENOK) is one of the endoplasmic reticulum (ER) proteins that mainly functions in the regulation of ER stress, calcium flux, and antioxidant defense. Reactive oxygen species (ROS) is one of the key indicators of ferroptosis, and SELENOK inhibition could disrupt ROS balance, and consequently might cause ferroptosis. However, there are no previous studies about the mechanism of SELENOK in ferroptosis by regulating ROS. In this study, we report the effect of SELENOK inhibition on cell proliferation, viability, iron recycling-associated proteins, ROS, antioxidant enzymes, and lipid peroxidation of cervical cancer cells (HeLa cells). The results showed that ROS levels and iron-dependent lipid peroxidation were significantly enhanced, whereas cell viability and proliferation were significantly downregulated, and resulted in marked reductions in tumor size after SELENOK knockdown. SELENOK knockdown also caused steep decreases in glutathione peroxidase 4/glutathione levels and deterioration in ROS scavenging ability, and exacerbated ferroptosis in HeLa cells. Our findings elucidated that SELENOK knockdown could shrink tumor size by regulating ferroptosis, which might provide a theoretical basis for treating cervical cancer.

Selenomethionine Attenuates the Amyloid-ß Level by Both Inhibiting Amyloid-ß Production and Modulating Autophagy in Neuron-2a/AßPPswe Cells.

Alzheimer's disease (AD) is a complex and progressive neurological disorder, and amyloid-ß (Aß) has been recognized as the major cause of AD. Inhibiting Aß production and/or enhancing the clearance of Aß to reduce its levels are still the effective therapeutic strategies pursued in anti-AD research. In previous studies, we have reported that selenomethionine (Se-Met), a major form of selenium in animals and humans with significant antioxidant capacity, can reduce both amyloid-ß (Aß) deposition and tau hyperphosphorylation in a triple transgenic mouse model of AD. In this study, a Se-Met treatment significantly decreased the Aß levels in Neuron-2a/AßPPswe (N2asw) cells, and the anti-amyloid effect of Se-Met was attributed to its ability to inhibit Aß generation by suppressing the activity of BACE1. Furthermore, both the LC3-II/LC3-I ratio and the number of LC3-positive puncta were significantly decreased in Se-Met-treated cells, suggesting that Se-Met also promoted Aß clearance by modulating the autophagy pathway. Subsequently, Se-Met inhibited the initiation of autophagy through the AKT-mTOR-p70S6K signaling pathway and enhanced autophagic turnover by promoting autophagosome-lysosome fusion and autophagic clearance. Our results further highlight the potential therapeutic effects of Se-Met on AD.

Selenomethionine Mitigates Cognitive Decline by Targeting Both Tau Hyperphosphorylation and Autophagic Clearance in an Alzheimer's Disease Mouse Model.

Tau pathology was recently identified as a key driver of disease progression and an attractive therapeutic target in Alzheimer's disease (AD). Selenomethionine (Se-Met), a major bioactive form of selenium (Se) in organisms with significant antioxidant capacity, reduced the levels of total tau and hyperphosphorylated tau and ameliorated cognitive deficits in younger triple transgenic AD (3xTg-AD) mice. Whether Se-Met has a similar effect on tau pathology and the specific mechanism of action in older 3xTg-AD mice remains unknown. Autophagy is a major self-degradative process to maintain cellular homeostasis and function. Autophagic dysfunction has been implicated in the pathogenesis of multiple age-dependent diseases, including AD. Modulation of autophagy has been shown to retard the accumulation of misfolded and aggregated proteins and to delay the progression of AD. Here, we found that 3xTg-AD mice showed significant improvement in cognitive ability after a 3-month treatment with Se-Met beginning at 8 months of age. In addition to attenuating the hyperphosphorylation of tau by modulating the activity of Akt/glycogen synthase kinase-3ß and protein phosphatase 2A, Se-Met-induced reduction of tau was also mediated by an autophagy-based pathway. Specifically, Se-Met improved the initiation of autophagy via the AMP-activated protein kinase-mTOR (mammalian target of rapamycin) signaling pathway and enhanced autophagic flux to promote the clearance of tau in 3xTg-AD mice and primary 3xTg neurons. Thus, our results demonstrate for the first time that Se-Met mitigates cognitive decline by targeting both the hyperphosphorylation of tau and the autophagic clearance of tau in AD mice. These data strongly support Se-Met as a potent nutraceutical for AD therapy.SIGNIFICANCE STATEMENT Selenium has been widely recognized as a vital trace element abundant in the brain with effects of antioxidant, anticancer, and anti-inflammation. In this study, we report that selenomethionine rescues spatial learning and memory impairments in aged 3xTg-AD mice via decreasing the level of tau protein and tau hyperphosphorylation. We find that selenomethionine promotes the initiation of autophagy via the AMPK-mTOR pathway and enhances autophagic flux, thereby facilitating tau clearance in vivo and in vitro We have now identified an additional, novel mechanism by which selenomethionine improves the cognitive function of AD mice. Specifically, our data suggest the effect of selenium/selenomethionine on an autophagic pathway in Alzheimer's disease.

Selenomethionine promoted hippocampal neurogenesis via the PI3K-Akt-GSK3ß-Wnt pathway in a mouse model of Alzheimer's disease.

The maintenance of neural system integrity and function is the ultimate goal for the treatment of neurodegenerative disease such as Alzheimer's disease (AD). Neurogenesis plays an integral role in the maintenance of neural and cognitive functions, and its dysfunction is regarded as a major cause of cognitive impairment in AD. Moreover, the induction of neurogenesis by targeting endogenous neural stem cells (NSCs) is considered as one of the most promising treatment strategies. Our previous studies demonstrated that selenomethionine (Se-Met) was able to reduce ß-amyloid peptide (Aß) deposition, decrease Tau protein hyperphosphorylation and markedly improve cognitive functions in triple transgenic (3xTg) AD mice. In this study, we reported that the therapeutic effect of Se-Met on AD could also be due to neurogenesis modulation. By using the cultured hippocampal NSCs from 3xTg AD mice, we discovered that Se-Met (1-10 µM) with low concentration could promote NSC proliferation, while the one with a high concentration (50,100 µM) inhibiting proliferation. In subsequent studies, we also found that Se-Met activated the signaling pathway of PI3K/Akt, and thereby inhibited the GSK3ß activity, which would further activated the ß-catenin/Cyclin-D signaling pathway and promote NSC proliferation. Besides, after the induction of Se-Met, the number of neurons differentiated from NSCs significantly increased, and the number of astrocytes decreased. After a 90-day treatment with Se-Met (6 µg/mL), the number of hippocampal neurons in 4-month-old AD mice increased significantly, while the one of astrocyte saw a sharp drop. Thus, Se-Met treatment promoted NSCs differentiation into neurons, and subsequently repaired damaged neural systems in AD mice. Being consistent with our in vitro studies, Se-Met acts through the PI3K-Akt- GSK3ß-Wnt signaling pathway in vivo. This study provides an unparalleled evidence that selenium (Se) compounds are, to some extent, effective in promoting neurogenesis, and therefore we propose a novel mechanism for Se-Met treatment in AD.

Karyotype analysis of Gossypium arboreum x G. bickii by genome in situ hybridization.

By using genome in situ hybridization (GISH) on root somatic chromosomes of allotetraploid derived from the cross Gossypium arboreum x G. bickii with genomic DNA (gDNA) of G. bickii as a probe, two sets of chromosomes, consisting of 26 chromosomes each, were easily distinguished from each other by their distinctive hybridization signals. GISH analysis directly proved that the hybrid G. arboreum x G. bickii is an allotetraploid amphiploid. The karyotype formula of the species was 2n = 4x = 52 = 46m (4sat) + 6sm (4sat). We identified four pairs of satellites with two pairs in each sub-genome. FISH analysis using 45S rDNA as a probe showed that the cross G. arboreum x G. bickii contained 14 NORs. At least five pairs of chromosomes in the G sub-genome showed double hybridization (red and blue) in their long arms, which indicates that chromatin introgression from the A sub-genome had occurred.

[Inhibition of tumor angiogenesis in nude mice by adenovirus-mediated PF4 p17-70 cDNA transfection].

OBJECTIVE: To investigate the in vivo effect of modified platelet factor 4 (PF4)-p17-70 cDNA on tumor angiogenesis in nude mice. METHODS: The p17-70 cDNA was cloned into the AdEasy system to transfect packing cell line 293 and produce viral particles encoding p17-70cDNA (Ad p17-70). The integration of p17-70 cDNA was confirmed by RT-PCR and the P17-40 peptide Western blot. The biological activity of purified recombinant adenovirus was determined by umbilical veinal endothelial cell proliferation assay in vitro and in vivo tumor angiogenesis suppression of nude mice bearing human head and neck carcinoma. RESULTS: p17-70 significantly inhibited in vitro proliferation of endothelial cells being 58% lower than that of empty vector and reduced tumor volume in vivo. The tumor mass was (0.086 +/- 0.054) g, (0.171 +/- 0.076) g and (0.195 +/- 0.067) g, the tumor volume was (16.7 +/- 5.2) mm(3), (36.5 +/- 23.7) mm(3) and (41.5 +/- 12.2) mm(3) in p17-70 cDNA transfected group, empty vector group and PBS group, respectively. Immunohistochemical staining demonstrated a decreased number of blood vessels in the tumors. CONCLUSION: P17-70 peptide mediated by adenoviral vector could inhibit the endothelial proliferation in vitro and the tumor growth in vivo.

[The effect of platelet factor 4 on the chemoattract function of the cord blood CD34+ cells].

AIM: To study the effect of PF4 and relative peptide PF4 17-70 on the chemoattract ability, the expression of adhesion molecules and CXCR4 on the flesh cord blood CD34+ cells. METHODS: CD34+ cells were separated from the cord blood using MACS immune magnetic beads, the chemoattract ability was assayed using the Transwell board, the expression of adhesion molecules and CXCR4 was measured by FACS. RESULTS: (1) PF4 and PF4 17-70 increased the migration of the CD34+ cells, the chemoattract percentage of PF4 was 157.43% +/- 50.06% (P < 0.05) and PF4 17-70 was 187.02% +/- 10.69% (P < 0.05). (2) The expression of CD49d and CXCR4 on the CD34+ cells increased after PF4 incubated, but the expressions of other adherent molecules including CD31, CD44, CD11a, CD62p, CD62E did not change. CONCLUSION: PF4 has the chemoattract ability on the umbilical blood CD34+ cells by promoting the expression of integrin CD49d and CXCR4, PF4 may help the cord stem cells homing.