Diagnostic and prognostic value of miR-200 family in breast cancer: A meta-analysis and systematic review

BackgroundBreast cancer (BC) is the most common cancer for women all over the world. Great interests have been paid to discover accurate and noninvasive methods for breast cancer diagnosis and prognosis. Although the diagnostic and prognostic value of microRNA-200 (miRNA- 200, miR-200) family has been revealed in many studies, the results were inconsistent. Thus, this meta-analysis aims to assess the overall value of miRNA-200 family in breast cancer diagnosis and prognosis.MethodRelevant studies were searched from the following databases: PubMed, PMC, EMBASE, and ScienceDirect using key words: ("miRNA-200 family" or "miR-141" or "miR-200a" or "miR-200b" or "miR-200c" or "miR-429") and (“HER2” or “Luminal A” or “Luminal B” or “TNBC”) and ("breast cancers" or "breast carcinoma" or "breast malignancy" or "breast tumor"). The sensitivity, specificity, AUC were then calculated to estimate the diagnostic accuracy of the miR-200 family. As for the prognostic value of the miR-200 family, the pooled hazard ratio (HR) was assessed. Heterogeneity among individual studies was also examined by subgroup analyses.ResultA total of 24 articles were included in the meta-analysis. The diagnostic value of miR-200s in BC was presented by the pooled sensitivity was 0.86 (95% CI: 0.83-0.88); the pooled specificity was 0.82 (95% CI: 0.72-0.89); the pooled AUC was 0.931 (95% CI: 0.919-0.942). Besides, expression of miR-200s in metastatic breast cancer has sensitivity, specificity and AUC of 0.70 (95%CI: 0.56-0.81), 0.72 (95%CI: 0.61-0.81), and 0.814 (95%CI: 0.741-0.903), respectively. The meta-analysis then revealed that high expression of miR-200 family corresponded to poor OS (HR: 1.63, 95% CI: 1.03-2.52), poor DFS (HR: 1.55, 95% CI: 0.95-2.56) in BC patients while downregulation of miRNA-200s corresponded to poor OS (HR= 0.84, 95%CI: 0.46-1.63) in TNBC patients and poor OS (HR=0.49; 95%CI: 0.27-0.88) in luminal BC patient.ConclusionThe MiR-200 family has high diagnostic accuracy and can be used as an important biomarker to prognosticate breast cancer.     

Glutamine-Fructose-6-Phosphate Transaminase 2 (GFPT2) Is Upregulated in Breast Epithelial–Mesenchymal Transition and Responds to Oxidative Stress

Breast cancer cells that have undergone partial epithelial–mesenchymal transition (EMT) are believed to be more invasive than cells that have completed EMT. To study metabolic reprogramming in different mesenchymal states, we analyzed protein expression following EMT in the breast epithelial cell model D492 with single-shot LFQ supported by a SILAC proteomics approach. The D492 EMT cell model contains three cell lines: the epithelial D492 cells, the mesenchymal D492M cells, and a partial mesenchymal, tumorigenic variant of D492 that overexpresses the oncogene HER2. The analysis classified the D492 and D492M cells as basal-like and D492HER2 as claudin-low. Comparative analysis of D492 and D492M to tumorigenic D492HER2 differentiated metabolic markers of migration from those of invasion. Glutamine-fructose-6-phosphate transaminase 2 (GFPT2) was one of the top dysregulated enzymes in D492HER2. Gene expression analysis of the cancer genome atlas showed that GFPT2 expression was a characteristic of claudin-low breast cancer. siRNA-mediated knockdown of GFPT2 influenced the EMT marker vimentin and both cell growth and invasion in vitro and was accompanied by lowered metabolic flux through the hexosamine biosynthesis pathway (HBP). Knockdown of GFPT2 decreased cystathionine and sulfide:quinone oxidoreductase (SQOR) in the transsulfuration pathway that regulates H₂S production and mitochondrial homeostasis. Moreover, GFPT2 was within the regulation network of insulin and EGF, and its expression was regulated by reduced glutathione (GSH) and suppressed by the oxidative stress regulator GSK3-β. Our results demonstrate that GFPT2 controls growth and invasion in the D492 EMT model, is a marker for oxidative stress, and associated with poor prognosis in claudin-low breast cancer.     

Integrated Application of Multiomics Strategies Provides Insights Into the Environmental Hypoxia Response in Pelteobagrus vachelli Muscle

Increasing pressures on aquatic ecosystems because of pollutants, nutrient enrichment, and global warming have severely depleted oxygen concentrations. This sudden and significant lack of oxygen has resulted in persistent increases in fish mortality rates. Revealing the molecular mechanism of fish hypoxia adaptation will help researchers to find markers for hypoxia induced by environmental stress. Here, we used a multiomics approach to identify several hypoxia-associated miRNAs, mRNAs, proteins, and metabolites involved in diverse biological pathways in the muscles of Pelteobagrus vachelli. Our findings revealed significant hypoxia-associated changes in muscles over 4 h of hypoxia exposure and discrete tissue-specific patterns. We have previously reported that P. vachelli livers exhibit increased anaerobic glycolysis, heme synthesis, erythropoiesis, and inhibit apoptosis when exposed to hypoxia for 4 h. However, the opposite was observed in muscles. According to our comprehensive analysis, fishes show an acute response to hypoxia, including activation of catabolic pathways to generate more energy, reduction of biosynthesis to decrease energy consumption, and shifting from aerobic to anaerobic metabolic contributions. Also, we found that hypoxia induced muscle dysfunction by impairing mitochondrial function, activating inflammasomes, and apoptosis. The hypoxia-induced mitochondrial dysfunction enhanced oxidative stress, apoptosis, and further triggered interleukin-1β production via inflammasome activation. In turn, interleukin-1β further impaired mitochondrial function or apoptosis by suppressing downstream mitochondrial biosynthesis–related proteins, thus resulting in a vicious cycle of inflammasome activation and mitochondrial dysfunction. Our findings contribute meaningful insights into the molecular mechanisms of hypoxia, and the methods and study design can be utilized across different fish species.     

Characterization of two M17 family members in Escherichia coli, Peptidase A and Peptidase B

Escherichia coli encodes two aminopeptidases belonging to the M17 family: Peptidase A (PepA) and Peptidase B (PepB). To gain insights into their substrate specificities, PepA or PepB were overexpressed in ΔpepN, which shows greatly reduced activity against the majority of amino acid substrates. Overexpression of PepA or PepB increases catalytic activity of several aminopeptidase substrates and partially rescues growth of ΔpepN during nutritional downshift and high temperature stress. Purified PepA and PepB display broad substrate specificity and Leu, Lys, Met and Gly are preferred substrates. However, distinct differences are observed between these two paralogs: PepA is more stable at high temperature whereas PepB displays broader substrate specificity as it cleaves Asp and insulin B chain peptide. Importantly, this strategy, i.e. overexpression of peptidases in ΔpepN and screening a panel of substrates for cleavage, can be used to rapidly identify peptidases with novel substrate specificities encoded in genomes of different organisms.     

Mouse erythroid cells express multiple putative RNA helicase genes exhibiting high sequence conservation from yeast to mammals

RNA secondary structure is a critical determinant of RNA function in ribosome assembly, pre-mRNA splicing, mRNA translation and RNA stability. The ‘DEAD/H’ family of putative RNA helicases may help regulate these processes by utilizing intrinsic RNA-dependent ATPase activity to catalyze conformational changes in RNA secondary structure. To investigate the repertoire of DEAD/H box proteins expressed in mammals, we used PCR techniques to clone from mouse erythroleukemia (MEL) cells three new DEAD box cDNAs with high similarity to known yeast (Saccharomyces cerevisiae) genes. mDEAD2 and mDEAD3 (mouse DEAD box proteins) are >95% identical to mouse PL10 but exhibit differential tissue-specific expression patterns; mDEAD2 and mDEAD3 are also approx. 70% identical (at the aa level) to yeast DED1 and DBP1 proteins. Members of this DEAD box subclass contain C-terminal domains with high content of Arg, Ser, Gly and Phe, reminiscent of the RS domain in several Drosophila and mammalian splicing factors. mDEAD5 belongs to a second class related to translation initiation factors from yeast (TIF1/TIF2) and mammals (eIF-4A); this class contains a novel conserved peptide motif not found in other DEAD box proteins. Northern blotting shows that mDEAD5 is differentially expressed in testis vs. somatic tissues. Thus, mouse erythroid cells produce two highly conserved families of putative RNA helicases likely to play important roles in RNA metabolism and gene expression.     

Inhibition of voltage-dependent Na+ current in cell-fusion hybrids containing activated c-Ha-ras

Summary The electrophysiological properties of EJ (human bladder carcinoma), GM2291 (human fetal lung fibroblast), and of three hybrid cell lines obtained from their cell fusion were investigated using the patch-clamp technique. GM2291 cells, which are nontumorigenic, express voltage-dependent Na⁺ channels. The pharmacology and gating properties of the Na⁺ channels in GM2291 cells are distinct from neuronal and cardiac Na⁺ channels. EJ cells, which are tumorigenic and contain activated c-Ha-ras, express inward rectifier K⁺ channels. The three cell-fusion hybrid lines, named 145 (nontumorigenic), 145L (non-tumorigenic but morphologically altered), and 147TR2 (fully tumorigenic segregant), have been previously shown to express levels of activated c-Ha-ras similar to those of the EJ parental line. Voltage-dependent Na⁺ channels were observed in none of the hybrid cell lines, while inward rectifier K⁺ channels were observed in each of the hybrid cell lines. The possibility that c-Ha-ras inhibits expression of a voltage-dependent Na⁺ channel is discussed.     

Sitosterol 3-O-α-riburonofuranoside from Bauhinia candicans

From the aerial parts of Bauhinia candicans a novel steroidal glycoside was isolated and identified as sitosterol 3-O-α-D-riburonofuranoside.     

DNA sequence analysis and structural relationships among the cytoskeletal actin genes of the sea urchinStrongylocentrotus purpuratus

Summary The general organization and primary amino acid sequences of theS. purpuratus cytoskeletal actin genes CyIIb and CyIIIb have been determined from restriction enzyme analysis, DNA sequencing, and RNA mapping studies. As is the case with the other sea urchin cytoskeletal actin genes previously studied, the CyIIb and CyIIIb genes contain two introns that interrupt the coding DNA following codon 121 and within codon 204. An intron ending 26–27 nucleotides (nt) upstream of the initiation codon has also been localized in the 5-flanking region of both genes. The CyIIb gene, which is part of a cluster of three genes linked in the order CyI-CyIIa-CyIIb, encodes a protein that differs from CyI by a single residue and from CyIIa by three residues. The substitutions observed within this linkage group are relatively conservative changes, and pairwise comparisons between genes indicate less than 5% mismatch in nucleotide sequence within the coding region. Nucleotide sequence comparisons of 5-flanking region and intron DNA, however, indicate greater similarity between the CyI and CyIIb genes than the CyIIa gene that separates them, suggestive of a potential gene conversion event between the flanking genes in the CyI-CyIIa-CyIIb linkage.The CyIIIb gene, part of a separate cluster of two functional genes ordered CyIIIa-CyIIIb, shares little similarity outside of coding DNA with genes of the other linkage group. Although CyIIIb exhibits strong nucleotide sequence similarity outside of coding DNA with the neighboring CyIIIa gene, it differs from that gene at six codons. The CyIIIb gene encodes a protein considerably different from all cytoskeletal actins previously reported, with changes clustered in the latter 40% of the coding sequence. An 81-nt tandem duplication of the C-terminal coding region is located adjacent to the termination codon of the CyIIIb gene, a potential relic of a slipped mispairing and replication event.     

Structure of a rice β-glucanase gene regulated by ethylene,cytokinin, wounding,salicylic acid and fungal elicitors

A rice -glucanase gene was sequenced and its expression analyzed at the level of mRNA accumulation. This gene (Gns1) is expressed at relatively low levels in germinating seeds, shoots, leaves, panicles and callus, but it is expressed at higher levels in roots. Expression in the roots appears to be constitutive. Shoots expressGns1 at much higher levels when treated with ethylene, cytokinin, salicylic acid, and fungal elicitors derived from the pathogenSclerotium oryzae or from the non-pathogenSaccharomyces cereviseae. Shoots also expressGns1 at higher levels in response to wounding. Expression in the shoots is not significantly affected by auxin, gibberellic acid or abscisic acid. The -glucanase shows 82% amino acid similarity to the barley 1,3;1,4--D-glucanases, and from hybridization studies it is the -glucanase gene in the rice genome closest to the barley 1,3;1,4--glucanase EI gene. The mature peptide has a calculated molecular mass of 32 kDa. The gene has a large 3145 bp intron in the codon for the 25th amino acid of the signal peptide. The gene exhibits a very strong codon bias of 99% G+C in the third position of the codon in the mature peptide coding region, but only 61% G+C in the signal peptide region.Abbreviations ABA abscisic acid - 2,4-D 2,4-dichlorophenoxyacetic acid - EtBr ethidium bromide - GA gibberellic acid - n.p. nucleotide position in gene sequence - PCR polymerase chain reaction - 1×SSPE 150 mM NaCl, 10 mM NaH₂PO₄, 1 mM EDTA pH 7.4