The effect of proteoglycans inhibited by RNA interference on metastatic characters of human salivary adenoid cystic carcinoma

<p>Abstract</p> <p>Background</p> <p>Salivary adenoid cystic carcinoma (SACC) is one of the most common malignancies of salivary gland. Recurrence or/and early metastasis is its biological properties. In SACC, neoplastic myoepithelial cells secrete proteoglycans unconventionally full of the cribriform or tubular and glandular structures of SACC. Literatures have demonstrated that extracellular matrix provided an essential microenvironment for the biological behavior of SACC. However, there is rare study of the effect of proteoglycans on the potential metastasis of SACC.</p> <p>In this study, human xylosyltransferase-I (XTLY-I) gene, which catalyzes the rate-limited step of proteoglycans biosynthesis, was knocked down by RNA interference (RNAi) to inhibit the proteoglycans biosynthesis in SACC cell line with high tendency of lung metastasis (SACC-M). The impact of down-regulated proteoglycans on the metastasis characters of SACC-M cells was analyzed and discussed. This research could provide a new idea for the clinical treatment of SACC.</p> <p>Methods</p> <p>The eukaryotic expression vector of short hairpin RNA (shRNA) targeting XTLY-I gene was constructed and transfected into SACC-M cells. A stably transfectant cell line named SACC-M-WJ4 was isolated. The XTLY-I expression was measured by real-time PCR and Western blot; the reduction of proteoglycans was measured. The invasion and metastasis of SACC-M-WJ4 cells were detected; the effect of down-regulated proteoglycans on the potential lung metastasis of nude mice was observed, respectively.</p> <p>Results</p> <p>The shRNA plasmid targeting XTLY-I gene showed powerful efficiency of RNAi. The mRNA level of target gene decreased by 86.81%, the protein level was decreased by 80.10%, respectively. The silence of XTLY-I gene resulted in the reduction of proteoglycans significantly in SACC-M-WJ4 cells. The inhibitory rate of proteoglycans was 58.17% (24 h), 66.06% (48 h), 57.91% (72 h), 59.36% (96 h), and 55.65% (120 h), respectively. The reduction of proteoglycans suppressed the adhesion, invasion and metastasis properties of SACC-M cells, and decreased the lung metastasis of SACC-M cells markedly either.</p> <p>Conclusion</p> <p>The data suggested that the silence of XTLY-I gene in SACC-M cells could suppress proteoglycans biosynthesis and secretion significantly. The reduction of proteoglycans inhibited cell adhesion, invasion and metastasis of SACC-M cells. There is a close relationship between proteoglycans and the biological behavior of SACC.</p

Developmental iodine deficiency resulting in hypothyroidism reduces hippocampal ERK1/2 and CREB in lactational and adolescent rats

BACKGROUND: Developmental iodine deficiency (ID) leads to inadequate thyroid hormone that impairs learning and memory with an unclear mechanism. Here, we show that hippocampal extracellular signal-regulated kinase (ERK1/2) and cAMP response element-binding protein (CREB) are implicated in the impaired learning and memory in lactational and adolescent rat hippocampus following developmental ID and hypothyroidism. METHODS: Three developmental rat models were created by administrating dam rats with either iodine-deficient diet or propylthiouracil (PTU, 5 ppm or 15 ppm)-added drinking water from gestational day (GD) 6 till postnatal day (PN) 28. Then, the total and phorsporylated ERK1/2 and total and phorsporylated CREB in the hippocampus were detected with western blot on PN14, PN21, PN28 and PN42. RESULTS: The iodine-deficient and hypothyroid pups showed lower serum FT3 and FT4 levels, smaller body size, and delayed eyes opening. The mean number of surviving cells in the hippocampus of the iodine-deficient and 15 ppm PTU-treated rats was significantly reduced compared to controls (P < 0.05). Iodine-deficient and 15 ppm PTU-treatment groups demonstrated significantly lower level of total and phosphorylated ERK1/2 and CREB than the controls on PN14, PN21 and PN28 (P < 0.05, respectively). The reduction of ERK1/2 and CREB was not reversible with the restoration of serum thyroid hormone concentrations on PN42. CONCLUSIONS: Developmental ID and hypothyroidism down-regulate hippocampal ERK1/2 and CREB in lactational and adolescent rats

GraphMAE2: A Decoding-Enhanced Masked Self-Supervised Graph Learner

Graph self-supervised learning (SSL), including contrastive and generative approaches, offers great potential to address the fundamental challenge of label scarcity in real-world graph data. Among both sets of graph SSL techniques, the masked graph autoencoders (e.g., GraphMAE)--one type of generative method--have recently produced promising results. The idea behind this is to reconstruct the node features (or structures)--that are randomly masked from the input--with the autoencoder architecture. However, the performance of masked feature reconstruction naturally relies on the discriminability of the input features and is usually vulnerable to disturbance in the features. In this paper, we present a masked self-supervised learning framework GraphMAE2 with the goal of overcoming this issue. The idea is to impose regularization on feature reconstruction for graph SSL. Specifically, we design the strategies of multi-view random re-mask decoding and latent representation prediction to regularize the feature reconstruction. The multi-view random re-mask decoding is to introduce randomness into reconstruction in the feature space, while the latent representation prediction is to enforce the reconstruction in the embedding space. Extensive experiments show that GraphMAE2 can consistently generate top results on various public datasets, including at least 2.45% improvements over state-of-the-art baselines on ogbn-Papers100M with 111M nodes and 1.6B edges.Comment: Accepted to WWW'2

Studies on the properties and the thermal decomposition kinetics of natural rubber prepared with calcium chloride

To evaluate calcium chloride coagulation technology, two kinds of raw natural rubber samples were produced by calcium chloride and acetic acid respectively. Plasticity retention index (PRI), thermal degradation process, thermal degradation kinetics and differential thermal analysis of two samples studied. Furthermore, thermal degradation activation energy, pre-exponential factor and rate constant were calculated. The results show that natural rubber produced by calcium chloride possesses good mechanical property and poor thermo-stability in comparison to natural rubber produced by acetic acid.<br /

Computational identification of rare codons of Escherichia coli based on codon pairs preference

<p>Abstract</p> <p>Background</p> <p>Codon bias is believed to play an important role in the control of gene expression. In <it>Escherichia coli</it>, some rare codons, which can limit the expression level of exogenous protein, have been defined by gene engineering operations. Previous studies have confirmed the existence of codon pair's preference in many genomes, but the underlying cause of this bias has not been well established. Here we focus on the patterns of rarely-used synonymous codons. A novel method was introduced to identify the rare codons merely by codon pair bias in <it>Escherichia coli</it>.</p> <p>Results</p> <p>In <it>Escherichia coli</it>, we defined the "rare codon pairs" by calculating the frequency of occurrence of all codon pairs in coding sequences. Rare codons which are disliked in genes could make great contributions to forming rare codon pairs. Meanwhile our investigation showed that many of these rare codon pairs contain termination codons and the recognized sites of restriction enzymes. Furthermore, a new index (F_rare) was developed. Through comparison with the classical indices we found a significant negative correlation between F_rareand the indices which depend on reference datasets.</p> <p>Conclusions</p> <p>Our approach suggests that we can identify rare codons by studying the context in which a codon lies. Also, the frequency of rare codons (F_rare) could be a useful index of codon bias regardless of the lack of expression abundance information.</p