Base editing with high efficiency in allotetraploid oilseed rape by A3A‐PBE system

CRISPR/Cas‐base editing is an emerging technology that could convert a nucleotide to another type at the target site. In this study, A3A‐PBE system consisting of human A3A cytidine deaminase fused with a Cas9 nickase and uracil glycosylase inhibitor was established and developed in allotetraploid Brassica napus. We designed three sgRNAs to target ALS, RGA and IAA7 genes, respectively. Base‐editing efficiency was demonstrated to be more than 20% for all the three target genes. Target sequencing results revealed that the editing window ranged from C1 to C10 of the PAM sequence. Base‐edited plants of ALS conferred high herbicide resistance, while base‐edited plants of RGA or IAA7 exhibited decreased plant height. All the base editing could be genetically inherited from T₀ to T₁ generation. Several Indel mutations were confirmed at the target sites for all the three sgRNAs. Furthermore, though no C to T substitution was detected at the most potential off‐target sites, large‐scale SNP variations were determined through whole‐genome sequencing between some base‐edited and wild‐type plants. These results revealed that A3A‐PBE base‐editing system could effectively convert C to T substitution with high‐editing efficiency and broadened editing window in oilseed rape. Mutants for ALS, IAA7 and RGA genes could be potentially applied to confer herbicide resistance for weed control or with better plant architecture suitable for mechanic harvesting.     

Acetaminophen sensitizing erastin-induced ferroptosis via modulation of Nrf2/heme oxygenase-1 signaling pathway in non-small-cell lung cancer

Growing evidence confirms that ferroptosis plays an important role in tumor growth inhibition. However, some non-small-cell lung cancer (NSCLC) cell lines are less sensitive to erastin-induced ferroptotic cell death. Elucidating the mechanism of resistance of cancer cells to erastin-induced ferroptosis and increasing the sensitivity of cancer cells to erastin need to be addressed. In our experiment, erastin and acetaminophen (APAP) cotreatment inhibited NSCLC cell viability and promoted ferroptosis and apoptosis, accompanied with attenuation of glutathione and ectopic increases in lipid peroxides. Erastin and APAP promoted NSCLC cell death by regulating nucleus translocation of nuclear factor erythroid 2-related factor 2 (Nrf2); and the ferroptosis induced by erastin and APAP was abrogated by bardoxolone methyl (BM) with less generation of reactive oxygen species and malondialdehyde. As a downstream gene of Nrf2, heme oxygenase-1 expression decreased significantly with the cotreatment of erastin and APAP, which could be rescued by BM. In vivo experiment showed that the combination of erastin and APAP had a synergic therapeutic effect on xenograft of lung cancer. In short, the present study develops a new effective treatment for NSCLC by synergizing erastin and APAP to induce ferroptosis.     

Three Meta-Analyses Define a Set of Commonly Overexpressed Genes from Microarray Datasets on Astrocytomas

Glioma is one of the most common tumors of the central nervous system, and one of its main types is astrocytoma. Microarray technology has been widely used to explore the molecular mechanism of cancer. It is universally accepted that meta-analysis considerably improves the statistical robustness of results, particularly in clinical research. To obtain the maximum reliability, we used three different meta-analyses to integrate the four microarray datasets, GSE16011, GSE4290, GSE2223, and GSE19728 (local), and defined the common differentially expressed genes (DEGs) in astrocytomas compared with normal brain tissue. Four DEGs, PCNA, CDC2, CDK2 and CCNB2, which are components of the cell cycle pathway, were chosen for Real-Time Polymerase Chain Reaction (RT-PCR) and immunohistochemistry validation. PCNA is similar to the P53 gene and has been widely implicated in various cancers including gliomas. Therefore, the expression status of PCNA in our study was considered as a reference to test our whole experimental scheme, and the results indicate that our methodology is valid. Although a few studies have reported the overexpression of the CDC2, CDK2 and CCNB2 genes in glioma cell lines, we are the first to identify the statuses of these genes in human astrocytoma tissues at the mRNA and protein levels. The results of the gene validations strongly suggested that the genes play an important role in astrocytomas and could potentially be valuable in the diagnosis and treatment of astrocytoma.     

Integrated Intercalation‐Based and Interfacial Sodium Storage in Graphene‐Wrapped Porous Li4Ti5O12 Nanofibers Composite Aerogel

Sodium storage in both solid–liquid and solid–solid interfaces is expected to extend the horizon of sodium‐ion batteries, leading to a new strategy for developing high‐performance energy‐storage materials. Here, a novel composite aerogel with porous Li₄Ti₅O₁₂ (PLTO) nanofibers confined in a highly conductive 3D‐interconnected graphene framework (G‐PLTO) is designed and fabricated for Na storage. A high capacity of 195 mA h g^?1 at 0.2 C and super‐long cycle life up to 12 000 cycles are attained. Electrochemical analysis shows that the intercalation‐based and interfacial Na storage behaviors take effect simultaneously in the G‐PLTO composite aerogel. An integrated Na storage mechanism is proposed. This study ascribes the excellent performance to the unique structure, which not only offers short pathways for Na⁺ diffusion and conductive networks for electron transport, but also guarantees plenty of PLTO–electrolyte and PLTO–graphene interfacial sites for Na⁺ adsorption.     

Integrated analysis of gene expression and methylation profiles of novel pancreatic cancer cell lines with highly metastatic activity

Pancreatic cancer is one of the most lethal human malignancies, partly because of its propensity for metastasis. However, highly metastatic human pancreatic cancer cell lines suitable for studies of metastasis are currently lacking. Here we established two highly metastatic human pancreatic cancer cell lines, MIA PaCa-2 In8 and Panc-1 In8, by Matrigel induction assay. The cell lines were further characterized both in vitro and in vivo. MIA PaCa-2 In8 and Panc-1 In8 cells demonstrated increased migration and invasion compared with their respective parental cells. Following injection into nude mice, MIA PaCa-2 In8 and Panc-1 In8 cells resulted in more pulmonary metastases compared with the parental cells. Furthermore, analyses of m RNA, long non-coding RNA, micro RNA, and methylation profiling revealed that these factors were aberrantly regulated in the highly metastatic cells,indicating that they probably affected metastasis. We thus established and characterized two highly metastatic human pancreatic cell lines that could be used as valuable tools for future investigations into the pathogenesis, metastasis, and potential treatment of human pancreatic cancer.     

Anti-oncogenic PTEN induces ovarian cancer cell senescence by targeting P21

Deletion and mutation of phosphatase and tensin homolog deleted on chromosome10 (PTEN) are closely associated with the occurrence of tumors. Tumor suppressor gene PTEN mutation plays an important role in the pathogenesis of ovarian cancer. However, it has been unclear whether it can regulate the senescence of ovarian cancer cells. We speculated that PTEN might inhibit the occurrence and development of ovarian cancer by promoting the expression of P21. We found that the expression of TRIM39 in human ovarian cancer was significantly diminished. In SKOV3 cells treated with naringin, the expression of TRIM39, which binds P21 and inhibits P21 degradation, was significantly elevated. Real-time polymerase chain reaction (PCR), Western blot, and immunofluorescence were used to detected the expression of PTEN, p21, and TRIM39, β-galactosidase Staining was used to detect cell senescence, Ki67 staining was used to observe cell proliferation, Trim39 interference or overexpression assay was used to detect its function. We speculated that PTEN might promote SKOV3 cell senescence by increasing TRIM39 expression and decreasing P21 degradation. Furthermore, by interfering with TRIM39 in SKOV3 cells, we found that the expression of P21 was downregulated, and the number of senescent SKOV3 cells decreased. With overexpression of TRIM39 in SKOV3 cells, the expression of P21 was upregulated, and the number of senescent SKOV3 cells increased. When naringin, a PTEN agonist, was added to SKOV3 cells in which TRIM39 protein was interfered with, the expression of P21 was significantly lower than that in the control group, and the number of senescent ovarian cancer cells was significantly diminished. Our results indicated that PTEN maintained the stability of P21 and decreased the degradation of P21 by increasing TRIM39 expression, thus promoting the senescence of SKOV3 cells, and PTEN maintained the stability of p21 and promoted the aging of SKOV3 cells might be a novel therapeutic target for ovarian cancer.     

微嗜酸寡养单胞菌中的漆酶对黄曲霉毒素B1降解脱毒的生物活性

[目的]探究微嗜酸寡养单胞菌中的漆酶对AFB1的降解活性,并确定漆酶在菌株CW117降解代谢AFB1过程中的贡献.[方法]从微嗜酸寡养单胞菌基因组中,共筛选到两个漆酶基因lc1和lc2,并用大肠杆菌BL21外源表达蛋白rLC1和rLC2,在体外检测其对AFB1的降解活性.同时参考前人报道,研究了氧化性辅剂对漆酶AFB1...     

Bcl‐2 hijacks the arsenic trioxide resistance in SH‐SY5Y cells

Aresenic trioxide (ATO) is proven to be active against leukaemia cells by inducing apoptosis and differentiation. Even though ATO could effectively induce remissions of leukaemia cells, the drug resistance was observed occasionally. To further dissect the mechanism of ATO resistance, we selected the ATO‐resistant SH‐SY5Y cells and found that Bcl‐2 controlled the sensitivity of ATO in SH‐SY5Y cells. We report that necroptosis, autophagy, NF‐ƘB and MAPK signalling pathway are not involved in ATO‐induced apoptosis. Moreover, the ATO‐resistant cells showed distinct mitochondrial morphology compared with that of ATO‐sensitive cells. Intriguingly, nude mice‐bearing ATO‐sensitive cells derived xenograft tumours are more sensitive to ATO treatment compared with that of ATO‐resistant cells. These data demonstrate that cancer cells can acquire the ATO‐resistance ability by increasing the Bcl‐2 expression.     

一种降低dATP用量的简单易错PCR方法

易错PCR是基因体外诱变的主要方法之一,是通过在PCR体系中添加Mn2+、提高Mg2+浓度和dCTP/dTTP浓度等措施达到基因诱变的目的。【目的和方法】本研究在不添加Mn2+、不调整其它任何PCR成分的情况下,通过降低dATP浓度的底物不平衡作用,对洋葱抗菌蛋白基因Ace-AMP1和苏云金芽胞杆菌毒蛋白(Bt)基因cry1A(c)进行了PCR诱变。【结果】结果表明:随着dATP浓度的降低,序列变异率和碱基突变率均呈升高趋势。当dTTP/dCTP/dGTP∶dATP在20∶1-40∶1时,碱基突变率介于1.4%-1.8%之间,序列变异率介于77.8%-100%之间。【讨论和结论】该方法简化了常规易错PCR诱变中的条件优化过程,简单实用。降低dATP浓度的诱变方法主要引起AT→GC的变异,适用于提高靶基因GC含量的体外诱变。本研究降低单一底物浓度的诱变方法可以提高诱变基因的AT或GC含量,是对易错PCR诱变方法的拓展。