m6A-induced lncRNA RP11 triggers the dissemination of colorectal cancer cells via upregulation of Zeb1.

BACKGROUND: Long noncoding RNAs (lncRNAs) have emerged as critical players in cancer progression, but their functions in colorectal cancer (CRC) metastasis have not been systematically clarified. METHODS: lncRNA expression profiles in matched normal and CRC tissue were checked using microarray analysis. The biological roles of a novel lncRNA, namely RP11-138 J23.1 (RP11), in development of CRC were checked both in vitro and in vivo. Its association with clinical progression of CRC was further analyzed. RESULTS: RP11 was highly expressed in CRC tissues, and its expression increased with CRC stage in patients. RP11 positively regulated the migration, invasion and epithelial mesenchymal transition (EMT) of CRC cells in vitro and enhanced liver metastasis in vivo. Post-translational upregulation of Zeb1, an EMT-related transcription factor, was essential for RP11-induced cell dissemination. Mechanistically, the RP11/hnRNPA2B1/mRNA complex accelerated the mRNA degradation of two E3 ligases, Siah1 and Fbxo45, and subsequently prevented the proteasomal degradation of Zeb1. m6A methylation was involved in the upregulation of RP11 by increasing its nuclear accumulation. Clinical analysis showed that m6A can regulate the expression of RP11, further, RP11 regulated Siah1-Fbxo45/Zeb1 was involved in the development of CRC. CONCLUSIONS: m6A-induced lncRNA RP11 can trigger the dissemination of CRC cells via post-translational upregulation of Zeb1. Considering the high and specific levels of RP11 in CRC tissues, our present study paves the way for further investigations of RP11 as a predictive biomarker or therapeutic target for CRC.

The miRNA-Mediated Post-Transcriptional Regulation of Maize in Response to High Temperature.

High temperature (HT) has recently become one of the most important abiotic stresses restricting crop production worldwide. MicroRNAs (miRNAs) are important regulators in plant development and stress responses. However, knowledge of miRNAs of maize in response to HT is limited. In this study, we simultaneously adopted miRNA sequencing and transcriptome profiling to analyze the differential expression of miRNAs and mRNAs in maize during exposure to HT stress. Our analysis revealed 61 known miRNAs belonging to 26 miRNA families and 42 novel miRNAs showing significant differential expression, with the majority being downregulated. Meanwhile, the expression of 5450 mRNAs was significantly altered in the same stressed tissues. Differentially expressed transcripts were most significantly associated with response to stress, photosynthesis, biosynthesis of secondary metabolites, and signal transduction pathways. In addition, we discovered 129 miRNA­mRNA pairs that were regulated antagonistically, and further depiction of the targeted mRNAs indicated that several transcription factors, protein kinases, and receptor-like-protein-related transmembrane transport and signaling transduction were profoundly affected. This study has identified potential key regulators of HT-stress response in maize and the subset of genes that are likely to be post-transcriptionally regulated by miRNAs under HT stress.

A Pilot Study of Radiomic Based on Routine CT Reflecting Difference of Cerebral Hemispheric Perfusion.

Background: To explore the effectiveness of radiomics features based on routine CT to reflect the difference of cerebral hemispheric perfusion. Methods: We retrospectively recruited 52 patients with severe stenosis or occlusion in the unilateral middle cerebral artery (MCA), and brain CT perfusion showed an MCA area with deficit perfusion. Radiomics features were extracted from the stenosis side and contralateral of the MCA area based on precontrast CT. Two different region of interest drawing methods were applied. Then the patients were randomly grouped into training and testing sets by the ratio of 8:2. In the training set, ANOVA and the Elastic Net Regression with fivefold cross-validation were conducted to filter and choose the optimized features. Moreover, different machine learning models were built. In the testing set, the area under the receiver operating characteristic (AUC) curve, calibration, and clinical utility were applied to evaluate the predictive performance of the models. Results: The logistic regression (LR) for the triangle-contour method and artificial neural network (ANN) for the semiautomatic-contour method were chosen as radiomics models for their good prediction efficacy in the training phase (AUC = 0.869, 0.873) and the validation phase (AUC = 0.793, 0.799). The radiomics algorithms of the triangle-contour and semiautomatic-contour method were implemented in the whole training set (AUC = 0.870, 0.867) and were evaluated in the testing set (AUC = 0.760, 0.802). According to the optimal cutoff value, these two methods can classify the vascular stenosis side class and normal side class. Conclusion: Radiomic predictive feature based on precontrast CT image could reflect the difference of cerebral hemispheric perfusion to some extent.

Foliar Application of Spermidine Alleviates Waterlogging-Induced Damages to Maize Seedlings by Enhancing Antioxidative Capacity, Modulating Polyamines and Ethylene Biosynthesis.

Waterlogging is a major threat to maize production worldwide. The exogenous application of spermidine is well known to enhance plant tolerance to abiotic stresses. The role of exogenous spermidine application in waterlogging tolerance in maize was investigated in this study. Two maize varieties (a waterlogging-tolerant variety: Xundan 20 (XD20) and a waterlogging-sensitive variety: Denghai 662 (DH662)) were subjected to waterlogging stress at the seedling stage, and then foliar spraying of 0.75 mM spermidine or purified water. Findings demonstrated lower chlorophyll content, reduced growth indices, considerable increase in superoxide anion (O2-) generation rate, and H2O2/malondialdehyde accumulation in the two maize varieties under waterlogging stress compared to the control treatment. However, the tolerance variety performed better than the sensitive one. Foliar application of spermidine significantly increased antioxidant enzyme activities under waterlogging stress. In addition, the application of spermidine increased polyamine levels and led to the reduction of ethylene levels under waterlogging. Consequences of spermidine application were most apparent for the waterlogging-sensitive cultivar DH662 under waterlogging than the waterlogging-tolerant variety XD20.

Ovary Abortion Induced by Combined Waterlogging and Shading Stress at the Flowering Stage Involves Amino Acids and Flavonoid Metabolism in Maize.

Maize (Zea mays L.) crops on the North China Plain are often subject to continuous overcast rain at the flowering stage. This causes waterlogging and shading stresses simultaneously and leads to huge yield losses, but the causes of these yield losses remain largely unknown. To explore the factors contributing to yield loss caused by combined waterlogging and shading stress at the flowering stage, we performed phenotypic, physiological, and quasi-targeted metabolomics analyses of maize plants subjected to waterlogging, shading, and combined waterlogging and shading (WS) treatments. Analyses of phenotypic and physiological indexes showed that, compared with waterlogging or shading alone, WS resulted in lower source strength, more severe inhibition of ovary and silk growth at the ear tip, a reduced number of emerged silks, and a higher rate of ovary abortion. Changes in carbon content and enzyme activity could not explain the ovary abortion in our study. Metabolomic analyses showed that the events occurred in ovaries and silks were closely related to abortion, WS forced the ovary to allocate more resources to the synthesis of amino acids involved in the stress response, inhibited the energy metabolism, glutathione metabolism and methionine salvage pathway, and overaccumulation of H2O2. In silks, WS led to lower accumulation levels of specific flavonoid metabolites with antioxidant capacity, and to over accumulation of H2O2. Thus, compared with each single stress, WS more seriously disrupted the normal metabolic process, and resulted more serious oxidative stress in ovaries and silks. Amino acids involved in the stress response in ovaries and specific flavonoid metabolites with antioxidant capacity in silks play important roles during ovary abortion. These results identify novel traits for selection in breeding programs and targets for genome editing to increase maize yield under WS stress.

HDAC8 promotes the dissemination of breast cancer cells via AKT/GSK-3ß/Snail signals.

The mechanistic action of histone deacetylase 8 (HDAC8) in cancer motility, including epithelial-mesenchymal transition (EMT), remains largely undefined. We found that the expression of HDAC8 was upregulated in breast cancer (BC) cells and tissues as compared to the controls. Further, BC tissues had the highest values of HDAC8 expression among 31 kinds of cancers. Cellular study indicated that HDAC8 can positively regulate the dissemination and EMT of BC cells. It increased the protein stability of Snail, an important regulator of EMT, by phosphorylation of its motif 2 in serine-rich regions. There are 21 factors that have been reported to regulate the protein stability of Snail. Among them, HDAC8 can decrease the expression of GSK-3ß through increasing its Ser9-phosphorylation. Mass spectrum analysis indicated that HDAC8 interact with AKT1 to decrease its acetylation while increase its phosphorylation, which further increased Ser9-phosphorylation of GSK-3ß. The C-terminal of AKT1 was responsible for the interaction between HDAC8 and AKT1. Further, Lys426 was the key residue for HDAC8-regulated deacetylation of AKT1. Moreover, HDAC8/Snail axis acted as adverse prognosis factors for in vivo progression and overall survival (OS) rate of BC patients. Collectively, we found that HDAC8 can trigger the dissemination of BC cells via AKT/GSK-3ß/Snail signals, which imposed that inhibition of HDAC8 is a potential approach for BC treatment.

Inhibition of BRD4 suppresses the malignancy of breast cancer cells via regulation of Snail.

The mechanistic action of bromodomain-containing protein 4 (BRD4) in cancer motility, including epithelial-mesenchymal transition (EMT), remains largely undefined. We found that targeted inhibition of BRD4 reduces migration, invasion, in vivo growth of patient-derived xenograft (PDX), and lung colonization of breast cancer (BC) cells. Inhibition of BRD4 rapidly decreases the expression of Snail, a powerful EMT transcription factor (EMT-TF), via diminishing its protein stability and transcription. Protein kinase D1 (PRKD1) is responsible for BRD4-regulated Snail protein stability by triggering phosphorylation at Ser11 of Snail and then inducing proteasome-mediated degradation. BRD4 inhibition also suppresses the expression of Gli1, a key transductor of Hedgehog (Hh) required to activate the transcription of SNAI1, in BC cells. The GACCACC sequence (-341 to -333) in the SNAI1 promoter is responsible for Gli1-induced transcription of SNAI1. Clinically, BRD4 and Snail levels are increased in lung-metastasized, estrogen receptor-negative (ER-), and progesterone receptor-negative (PR-) breast cancers and correlate with the expression of mesenchymal markers. Collectively, BRD4 can regulate malignancy of breast cancer cells via both transcriptional and post-translational regulation of Snail.

Targeting CDK7 increases the stability of Snail to promote the dissemination of colorectal cancer.

Targeted inhibition of cyclin-dependent kinase 7 (CDK7) via its covalent inhibitor THZ1 can suppress the growth of various cancers, while its roles on colorectal cancer (CRC) remain obscure. Here we report that the expression of CDK7 is upregulated in CRC cells and tissues. THZ1 exhibits high potency and selectivity against CRC cells both in vitro and in vivo via induction of cell apoptosis rather than cell cycle disruption. Intriguingly, THZ1 treatment increases the ability of epithelial mesenchymal transition (EMT) and in vivo metastasis to liver of CRC cells. Mechanistical studies reveal that THZ1 increases the expression of Snail, while not other EMT-transcription factors, via enhancing its protein stability rather than mRNA expression or translation. By screening Snail stability related factors via qRT-PCR, results indicate THZ1 and si-CDK7 decrease the expression of protein kinase D1 (PKD1) in CRC cells. Down regulation of PKD1 mediates THZ1 up regulated Snail via dephosphorylation of Snail Ser 11 and prevention of proteasome mediated degradation. Clinical analysis confirms that CDK7 is significantly (p < 0.05) negatively correlated with the expression of mesenchymal markers including FN1, VIM, and MMP2. CRC patients whose tumors expressing less CDK7/SNAI1 or PKD1/SNAI1 showed significant (p < 0.05) poorer overall survival (OS) rate as compared with those with greater levels. Collectively, our data suggest that targeted inhibition of CDK7 can trigger the metastasis of CRC during cancer development via PKD1/Snail axis, which imposes great challenge that inhibition of CDK7 is a potential approach for cancer treatment.

Histone deacetylase 8 triggers the migration of triple negative breast cancer cells via regulation of YAP signals.

Triple-negative breast cancer (TNBC) shows highly aggressive clinical behaviors and poor prognosis compared to other breast cancer subtypes. Histone deacetylases (HDACs) can regulate the progression of various cancers, but the role of HDAC8 in TNBC remains unexplored. Here, we found that HDAC8 enhanced the in vitro migration abilities of breast cancer cells. Targeted inhibition of HDAC8 via si-HDAC8 and its selective inhibitor PCI34051 could suppress the migration of cells. In TNBC cells, HDAC8 stabilized the expression and increased the nuclear localization of YAP, a major downstream effector of Hippo pathway. While silencing YAP could attenuate HDAC8 triggered migration of TNBC cells. Mechanistically, HDAC8 suppressed the phosphorylation of YAPSer127, which was related to its cytoplasmic sequestration degradation. Our data revealed that HDAC8 could trigger the migration of TNBC cells via regulation of Hippo-YAP signals, suggesting that HDAC8 might be a potential target for TNBC therapy.