Clinical implications of PNA‑sequencing as a complementary test for EGFR mutation analysis in human lung cancer

Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) are the first-line regimen for the treatment of non-small cell lung cancer (NSCLC) patients with EGFR mutations. However, false-negative results are occasionally observed, even with FDA-approved molecular tests. Such examples in have been reported in our pilot study showing a slightly upward-shifted amplification curve using commercial reverse transcription-quantitative (RT-q)PCR. Verification using peptide nucleic acid (PNA) clamping-sequencing, which has a sensitivity of ~0.1%, may allow better prediction of which patients will benefit from EGFR-TKI therapy. To confirm this hypothesis, samples were prospectively collected from 1,783 lung cancer cases diagnosed in National Cheng Kung University Hospital between 2012-2018. An independent lung cancer cohort of 1,944 cases was also recruited from other hospitals. The clinical significance of mutant-enriched PCR with PNA-sequencing was analyzed and patient outcomes were followed. A total of 17 of 34 cases (50%) were found to harbor EGFR mutations by PNA-sequencing. A total of 22 cases were discovered in the independent lung cancer cohort, and 14 of these (63.6%) cases had EGFR mutations. TKIs were administered to 14 of the 17 mutation-positive patients, and a partial response was observed in 4 cases and stable disease in 10 cases. Patients with EGFR mutations receiving a TKI regimen had a longer overall survival (OS) (median: 40.0 vs. 10.0 months) compared with those without treatment. The difference in OS was not significant. Based on the results of the present study, combining RT-qPCR with PNA-sequencing may be a practical supplementary technology in a clinical molecular laboratory for a subset of lung cancer patients in selection of EGFR TKI therapy.

CircRNA expression profiling of PBMCs from patients with hepatocellular carcinoma by RNA-sequencing

Circular RNAs (circRNAs) are differentially expressed in various cancer types. The present study aimed to investigate the expression and clinical implication of circRNAs in hepatocellular carcinoma (HCC) and to evaluate the potential of circRNAs as diagnostic biomarkers for HCC. CircRNA expression was profiled in 19 patients with HCC and 19 normal controls using ribosomal RNA-depleted RNAs. Differentially expressed circRNAs (DE-circRNAs) between HCC and controls were identified using CIRI2 and distinct circRNA expression signatures were screened. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes were used to predict the potential functions of these DE-circRNAs and the circRNA-miRNA-mRNA regulatory networks were then constructed. Several DE-circRNAs were selected and confirmed by RT-qPCR. A total of 40 DE-circRNAs (27 upregulated and 13 downregulated) were identified between patients with HCC and controls. Functional annotation indicated that these DE-circRNAs were involved in cellular components, molecular functions and cancer-associated pathways related to HCC. These included pathways in cancer, TNF signaling pathway, hepatitis B, hepatitis C and hepatocyte differentiation. The circRNA-miRNA-mRNA regulatory network was generated based on 11 candidate circRNAs. Receiver operating characteristic curve analysis indicated that Homo sapiens (hsa)_circ_0073239, hsa_circ_007090, hsa_circ_0008304, hsa_circ_0017586, hsa_circ_0000369 and hsa_circ_0001181 may serve as potential biomarkers for HCC. Results from Cell Counting Kit-8 assay suggested that small interfering RNA targeting hsa_circ_0001181 reduced the proliferation of HepG2 cells, which implicated it as a potential therapeutic target for HCC. Therefore, in the present study, the differential expression pattern and important role of circRNAs in HCC were determined. The present results highlight the diagnostic potential of circRNAs in HCC and provide novel insight into the development of and treatment approaches for HCC.

Expression of immune check point gene TIM-3 in patients newly diagnosed with acute myeloid leukemia: Significance and impact on outcome

Despite recent advancements in the therapeutic landscape of acute myeloid leukemia (AML), the prognosis of patients remains poor. Immune check point inhibitors have been investigated in hematological malignancies, including AML; however, the role of T-cell immunoglobulin and mucin domain 3 (TIM-3) in AML has not yet been fully elucidated. Thus, the present study aimed to investigate TIM-3 gene expression in patients with AML and determine its associations with prognostic variables and clinical outcome. A total of 60 patients newly diagnosed with AML and 15 healthy matching individuals were recruited in the present study, and reverse transcription-quantitative PCR analysis was performed to detect TIM-3 expression. The results demonstrated that TIM-3 expression was significantly upregulated in patients with AML compared with that in healthy individuals (P<0.001). In addition, patients with extramedullary disease (EMD) exhibited significantly lower median TIM-3 expression levels compared with those without EMD (P=0.001). Furthermore, patients with high TIM-3 expression had significantly lower complete remission rates following induction chemotherapy compared with those with low TIM-3 expression (P=0.004). High TIM-3 expression was significantly associated with lower overall survival rates during the 1-year follow-up (P=0.001). Taken together, the results of the present study suggest that TIM-3 may act as a biomarker of a poor prognosis in patients with AML, and be used as a therapeutic target.

EZH2 and SMYD3 expression in papillary thyroid cancer

Recent studies have revealed the significant role of SMYD3 and EZH2 genes in the development and aggressiveness of numerous types of malignant tumor. Therefore, the present study aimed to investigate the expression of SMYD3 and EZH2 in papillary thyroid cancer, and to determine the correlation between the expression of these genes and clinical characteristics. Resected thyroid tissue samples from 62 patients with papillary thyroid cancer were investigated. Thyroid tissue derived from the healthy regions of removed nodular goiters from 30 patients served as the control group. Reverse transcription-quantitative PCR analysis was employed to detect relative mRNA expression levels. Primer sequences and TaqMan^® hydrolysis probe positions for EZH2 and SMYD3 were determined using the Roche Universal ProbeLibrary Assay Design Center version 2.50. EZH2 expression was detected in all thyroid cancer samples and in 83.3% of benign lesions. Notably, EZH2 was revealed to be upregulated in thyroid cancer tissues compared with control tissues (P=0.0002). EZH2 expression was positively correlated with tumor stage (P<0.0001; r=0.504), and multiple comparison analysis revealed that the highest expression of EZH2 was detected in samples staged pT4 (P=0.0001). SMYD3 expression was detected in all thyroid cancer samples and in 96.7% of healthy thyroid tissues; notably, the expression levels were similar in both groups. In addition, there was no correlation between SMYD3 expression and the aggressiveness of papillary thyroid cancer. In conclusion, overexpression of the EZH2 gene may be associated with the development of papillary thyroid cancer and EZH2 may be a potential therapeutic target in papillary thyroid cancer.

Selection and validation of optimal endogenous reference genes for analysis of quantitative PCR in four tissues pathologically associated with Kidney-yang deficiency syndrome following influenza A infection

Kidney-yang deficiency syndrome (KYDS) infected with the influenza virus is a suitable model to imitate a population at high-risk to influenza infection with a high rate of morbidity and mortality. However, the specific molecular mechanisms underlying this disease remain unclear. A stable reference gene is essential as an internal control for molecular biology research of this condition. Reverse-transcription-quantitative PCR (RT-qPCR) is considered an extremely sensitive technique used for absolute and relative quantification of target genes transcript levels. To accurately estimate the relative expression of genes in cells from mice with KYDS in response to infection with influenza A virus subtype H1N1 (A/H1N1) virus using RT-qPCR, it is necessary to identify suitable reference genes. In the present study, analysis of 10 reference genes (Act-β, β2m, GAPDH, Gusβ, Tubα, Grcc10, Eif4h, Rnf187, Nedd8 and Ywhae) was performed across a set of 4 tissue types: Lung; heart; liver; and kidney. KYDS mice were inoculated with A/H1N1 virus or a mock control. For analysis, geNorm, BestKeeper, NormFinder, and Bio-Rad Maestro^™ statistical programs were used for the estimation of the stability of the reference genes. The results were authenticated through extended experimental settings using a group of 10 samples, parallel to 3 additional innate immune system-associated genes of the host, TLR3, TLR7 and RIG-I, which were also analyzed using the same algorithms. From the 4 algorithms, taking into account the joint analyses of the ranking order outputs, the 2 genes Ywhae and Nedd8 were identified to be the most stable for mice with KYDS following infection with A/H1N1 virus. In contrast, the least stable genes in all 4 tissues were GAPDH and β2m. These results may affect the choice of reference genes in future studies that use RT-qPCR analysis of target genes in experimental conditions, such as mice with KYDS infected with influenza A virus.

Transcriptome signatures reveal candidate key genes in the whole blood of patients with lumbar disc prolapse

The present study aimed to investigate differentially expressed genes (DEGs) in whole blood (WB) obtained from patients with lumbar disc prolapse (LDP) and healthy volunteers. A total of 8 patients with LDP and 8 healthy volunteers were recruited. An Agilent SurePrint G3 human gene expression microarray 8×60 K was used to perform the microarray analyses. R was employed to identify DEGs, which were then subjected to bioinformatics analysis, including a Gene Ontology (GO) analysis, Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathway analysis and protein-protein interaction (PPI) network analysis. DEGs in the degenerative annulus fibrosis (AF) and nucleus pulposus (NP) compared with non-degenerative tissues were also identified based on microarray data and the intersections of the three were assessed. Furthermore, reverse transcription-quantitative (RT-q)PCR was performed to confirm the aberrant expression levels of selected DEGs in the WB of all subjects. A total of 161 DEGs between LDP patients and the healthy controls were identified (128 upregulated and 33 downregulated). These DEGs were enriched in 293 biological process, 36 cellular component and 21 molecular function GO terms, as well as in 24 KEGG pathways. The PPI network contained 4 submodules, and Toll-like receptor 4 had the highest degree centrality. A total of 22 DEGs were common to the three groups of DEGs. The RT-qPCR assay confirmed that the expression levels of cytochrome P450 family 27 subfamily A member 1, superoxide dismutase 2, protein disulfide isomerase family A member 4, FKBP prolyl isomerase 11 and ectonucleotide pyrophosphatase/phosphodiesterase 4 were significantly different between the patient group and the volunteer group. In conclusion, several genes were identified as potential biomarkers in WB that should be further explored in future studies to determine their potential application in the clinical treatment and diagnosis of LDP, and the present bioinformatics analysis revealed several GO terms, KEGG pathways and submodules of the PPI network that may be involved in LDP, although the exact mechanisms remain elusive.

High interleukin-8 and/or extracellular signal-regulated kinase 2 expression predicts poor prognosis in patients with hepatocellular carcinoma

Interleukin (IL)-8 and extracellular signal-regulated kinase (ERK) 2 play key roles in tumor progression, but the relationship between IL-8 and/or ERK2 expression in hepatocellular carcinoma (HCC) tissues and postoperative recurrence or survival is unclear. The expression levels of IL-8 and ERK2 in both HCC tissues and non-tumor liver tissues were analyzed using the Oncomine™ database and immunohistochemistry assay. Reverse transcription-quantitative PCR was then used to evaluate the expression levels of IL-8 and ERK2 in the tumor tissues of 67 patients with HCC undergoing radical hepatectomy. Pearson's correlation, Kaplan-Meier, Cox univariate and multivariate survival analyses were utilized to determine the correlation between IL-8 and ERK2 expression in HCC tissues, and their potential prognostic significance. As indicated by the data from the Oncomine™ database, and the patient samples, IL-8 and ERK2 were expressed at significantly higher levels in HCC tissues than in non-tumor liver tissues (P<0.05). The rates of high IL-8 and ERK2 expression in HCC tissues were 43.28 (29/67) and 34.33% (23/67), respectively, and the IL-8 and ERK2 expression levels were positively correlated (r=0.764; P<0.001). Both ERK2 expression and IL-8/ERK2 co-expression were significantly associated with tumor size and differentiation (P<0.05). Additionally, high expression levels of IL-8, ERK2 and IL-8/ERK2 co-expression were all significantly associated with poor overall survival (OS; P<0.05) and disease-free survival (DFS; P<0.05). Multivariate Cox regression analysis also showed that high expression levels of IL-8, ERK2, and IL-8 and ERK2 were independent prognostic factors for OS and DFS (P<0.05). The results of the present study indicate a significant increase in the risk of recurrence and mortality in HCC patients with high expression levels of IL-8 and/or ERK2, compared with patients with low expression. Therefore, IL-8 and ERK2 may be predictors of postoperative prognosis in patients with HCC.

Identification and performance evaluation of housekeeping genes for microRNA expression normalization by reverse transcription-quantitative PCR using liquid-based cervical cytology samples

Screening for cervical cancer by cytology has been effective in reducing the worldwide incidence and mortality rates of this disease. However, a number of studies have demonstrated that the sensitivity of conventional cervical cytology may be too low for detection of cervical intraepithelial neoplasias (CIN). Therefore, it is important to incorporate more sensitive molecular diagnostic tests that could substantially improve the detection rates and accuracy for identifying CIN lesions. MicroRNAs (miRNAs) are a class of small non-coding RNAs with the potential to provide robust non-invasive cancer biomarkers for detecting CIN lesions in liquid-based cervical cytology (LBC) samples. At present, there is no consensus on which are the best housekeeping genes for miRNA normalization in LBC. The present study aimed to identify housekeeping genes with consistent and reproducible performance for normalization of reverse transcription-quantitative PCR (RT-qPCR) expression analysis of miRNA using LBC samples. The present study firstly selected six potential candidate housekeeping genes based on a systematic literature evaluation. Subsequently, the expression levels of microRNAs U6, RNU-44, RNU-47, RNU-48, RNU-49 and hsa-miR-16 were measured in 40 LBC samples using RT-qPCR. The stability of each potential housekeeping gene was assessed using the NormFinder algorithm. The results revealed that U6 and RNU-49 were the most stable genes among all candidates requiring fewer amplification cycles and smaller variation across the sample set. However, RNU-44, RNU-47, RNU-48 and hsa-miR-16 stability exceeded the recommended housekeeping value suitable for normalization. The findings revealed that U6 may be a reliable housekeeping gene for normalization of miRNA RT-qPCR expression analysis using LBC samples.

LncRNA TUG1 promotes the development of osteosarcoma through RUNX2

The lncRNA taurine-upregulated gene 1 (TUG1) is known to serve a role as an oncogene in the development of a number of human malignancies. However, the functionality of TUG1 in osteosarcoma remains poorly characterized. Therefore, the aim of the present study was to explore the role of TUG1 in osteosarcoma. TUG1 expression in tumor tissues, adjacent healthy tissues and plasma from 40 osteosarcoma patients and 40 healthy controls was detected using reverse transcription-quantitative PCR. Receiver operating characteristic curves were used to analyze the diagnostic value of TUG1 for osteosarcoma while the prognostic value of TUG1 for osteosarcoma was analyzed using the Kaplan-Meier method. TUG1 expression vectors and siRNAs were transfected into MG-63 and U2OS osteosarcoma cell lines, and the effects on osteosarcoma cell viability, migration and invasion were tested using Cell Counting kit-8 and Transwell assays. The effects of TUG1 overexpression on runt-related transcription factor 2 (RUNX2) expression were also detected using western blotting. TUG1 expression was found to be significantly higher in osteosarcoma tissues compared with adjacent healthy tissues, and in the plasma of osteosarcoma patients compared with healthy controls. TUG1 expression also exhibited significant diagnostic and prognostic value for osteosarcoma. TUG1 overexpression and knockdown respectively increased and reducedosteosarcoma cell viability, migration and invasion. In addition, TUG1 overexpression upregulated RUNX2 expression. These results suggest that lncRNA TUG1 may promote the development of osteosarcoma by modulating RUNX2 and TUG1 expression, which can serve as prognostic and diagnostic markers for this malignancy.

Clinical value of microRNA-198-5p downregulation in lung adenocarcinoma and its potential pathways

Lung adenocarcinoma (LUAD), the main subtype of non-small cell lung cancer, is known to be regulated by various microRNAs (miRs/miRNAs); however, the role of miR-198-5p in LUAD has not been clarified. In the present study, the clinical value of miR-198-5p in LUAD and its potential molecular mechanism was evaluated. miR-198-5p expression was examined by reverse transcription-quantitative PCR (RT-qPCR) in 101 paired LUAD and adjacent normal lung tissues. Subsequently, the miR-198-5p expression level was determined from microarray data from the Gene Expression Omnibus, ArrayExpress and by meta-analyses. Furthermore, the target mRNAs of miR-198-5p from 12 miRNA-mRNA predictive tools were intersected with The Cancer Genome Atlas (TCGA)-based differentially expressed genes. In addition, Gene Ontology annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were conducted to determine the possible mechanism of miR-198-5p in LUAD. The Search Tool for the Retrieval of Interacting Genes/Proteins database was employed to construct a protein-protein interaction network among the potential target genes of miR-198-5p. The results showed that miR-198-5p expression was lower in LUAD tissues than in adjacent non-cancerous lung tissues (4.469±2.495 vs. 5.301±2.502; P=0.015). Meta-analyses, including the data from the present study and online microarray data, also verified the downregulation of miR-198-5p in 584 cases of LUAD. The expression of miR-198-5p was associated with the age, blood vessel invasion, Tumor-Node-Metastasis stage, and lymph node metastasis of patients with LUAD and served as an independent prognostic factor for survival. The hub genes of miR-198-5p were upregulated in LUAD, according to TCGA and The Human Protein Atlas. For the KEGG pathway analysis, the most enriched KEGG pathway was the p53 signaling pathway (P=1.42×10⁻⁶). These findings indicated that the downregulation of miR-198-5p may play a pivotal role in the development of LUAD by targeting various signaling pathways.

Comparison of Reliable Reference Genes Following Different Hormone Treatments by Various Algorithms for qRT-PCR Analysis of Metasequoia

Quantitative reverse transcription polymerase chain reaction (qRT-PCR) is the most sensitive technique for evaluating gene expression levels. Choosing appropriate reference genes for normalizing target gene expression is important for verifying expression changes. Metasequoia is a high-quality and economically important wood species. However, few systematic studies have examined reference genes in Metasequoia. Here, the expression stability of 14 candidate reference genes in different tissues and following different hormone treatments were analyzed using six algorithms. Candidate reference genes were used to normalize the expression pattern of FLOWERING LOCUS T and pyrabactin resistance-like 8. Analysis using the GrayNorm algorithm showed that ACT2 (Actin 2), HIS (histone superfamily protein H3) and TATA (TATA binding protein) were stably expressed in different tissues. ACT2, EF1α (elongation factor-1 alpha) and HIS were optimal for leaves treated with the flowering induction hormone solution, while Cpn60β (60-kDa chaperonin β-subunit), GAPDH (glyceraldehyde-3-phosphate dehydrogenase) and HIS were the best reference genes for treated buds. EF1α, HIS and TATA were useful reference genes for accurate normalization in abscisic acid-response signaling. Our results emphasize the importance of validating reference genes for qRT-PCR analysis in Metasequoia. To avoid errors, suitable reference genes should be used for different tissues and hormone treatments to increase normalization accuracy. Our study provides a foundation for reference gene normalization when analyzing gene expression in Metasequoia.

External quality assessment of p210 BCR-ABL1 transcript quantification by RT-qPCR: Findings and recommendations

INTRODUCTION

External quality assessment (EQA) is an essential tool for quality assurance of analytical testing processes of p210 BCR-ABL1 transcripts by RT-qPCR. As an EQA provider, the National Center for Clinical Laboratories organized an EQA scheme of p210 BCR-ABL1 testing in China for the first time to identify existing problems and ensure the reliability of p210 BCR-ABL1 testing.

METHODS

Using armored RNA technology, we first constructed pACYC-MS2-p210 and CG recombinant plasmids and expressed p210 and CG armored RNAs, with packaging segments of p210 BCR-ABL1 fusion gene (FG) and four common control gene (CG) transcripts. Using these armored RNAs, we prepared lyophilized p210 quality control (QC) sample panels and evaluated detection performance of participating laboratories in China.

RESULTS

Of the 66 participating laboratories, great variation was found with coefficient of variation (CV%) of raw p210 BCR-ABL1 results basically ranging from 60.0% to 100.0%. In 24 International Scale (IS) laboratories, the CV% of results decreased from 82.4% to 61.6%, and the percentage of laboratories within 2-, 3-, and 5-fold of the median values increased from 78.2%, 87.0%, and 92.1% to 80.1%, 89.4%, and 97.2%, respectively, after conversion with a laboratory-specific conversion factor (CF); however, poorly converted results were also observed in laboratories resulting from changed components of RT-qPCR procedures. False-negative and false-positive results were also found in the EQA.

CONCLUSIONS

Various problems were found for p210 BCR-ABL1 detection in the EQA. By solving the existing problems, the performance of p210 BCR-ABL1 detection can be improved, ensuring robust laboratory diagnostic capacities in China.

Evaluation of reference genes for reverse transcription-quantitative PCR assays in organs of zebrafish exposed to glyphosate-based herbicide, Roundup

Roundup is a glyphosate-based herbicide (GBH) widely used in agriculture and may cause toxic effects in non-target organisms. Model organisms, as zebrafish, and analysis of gene expression by reverse transcription-quantitative PCR (RT-qPCR) could be used to better understand the Roundup toxicity. A prerequisite for RT-qPCR is the availability of appropriate reference genes; however, they have not been described for Roundup-exposed fish. The aim of this study was to evaluate the expression stability of six reference genes (rpl8, β-act, gapdh, b2m, ef1α, hprt1) and one expressed repetitive element (hatn10) in organs of males (brain, gill, testis) and females (ovary) of zebrafish exposed to Roundup WG at three concentrations (0.065, 0.65 and 6.5 mg N-(phosphonomethyl) glycine/l) for 7 days. Genes were ranked by geNorm, NormFinder, BestKeeper, Delta C t and RefFinder, and their best combinations were determined by geNorm and NormFinder programs. The two most stable ranked genes were specific to each organ: gill (β-act; rpl8); brain (rpl8; β-act); testis (ef1α; gapdh); and ovary (rpl8; hprt1). The cat transcript level was used to evaluate the effect of normalization with these reference genes. These are the first suitable reference genes described for the analysis of gene expression in organs of Roundup-exposed zebrafish, and will allow investigations of the molecular mechanisms of Roundup toxicity.

Analysis of Different Approaches for the Selection of Reference Genes in RT-qPCR Experiments: A Case Study in Skeletal Muscle of Growing Mice

The reliability of reverse transcription-quantitative PCR (RT-qPCR) results in gene expression studies depends on the approaches used to account for non-biological variations. In order to find a proper normalization strategy for the study of genes related to growth hormone signaling in skeletal muscle of growing mice, nine unrelated genes were evaluated as internal controls. According to the most used algorithms–geNorm, the Comparative ΔCq method, NormFinder and BestKeeper–GSK3B, YWHAZ, RPL13A and RN18S were found as the most stable. However, the relative expression levels of eight of the potential reference genes assessed decreased with age in cDNA samples obtained from the same amount of total RNA. In a different approach to analyze this apparent discrepancy, experiments were performed with cDNA obtained from equal amounts of purified mRNA. Since the decline was still observed, the hypothesis of an age-related change in mRNA to total RNA ratio that could account for the systematic decrease was rejected. Differences among experimental groups could be due to a substantial increase with age in highly expressed mRNAs, which would bias the quantitation of the remaining genes. Consequently, those reference genes reflecting this dilution effect, which would have been discarded considering their variable relative expression levels, arose as suitable internal controls.

Investigation of the Activity of the Microorganisms in a Reblochon-Style Cheese by Metatranscriptomic Analysis

The microbial communities in cheeses are composed of varying bacteria, yeasts, and molds, which contribute to the development of their typical sensory properties. In situ studies are needed to better understand their growth and activity during cheese ripening. Our objective was to investigate the activity of the microorganisms used for manufacturing a surface-ripened cheese by means of metatranscriptomic analysis. The cheeses were produced using two lactic acid bacteria (Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus), one ripening bacterium (Brevibacterium aurantiacum), and two yeasts (Debaryomyces hansenii and Geotrichum candidum). RNA was extracted from the cheese rinds and, after depletion of most ribosomal RNA, sequencing was performed using a short-read sequencing technology that generated ~75 million reads per sample. Except for B. aurantiacum, which failed to grow in the cheeses, a large number of CDS reads were generated for the inoculated species, making it possible to investigate their individual transcriptome over time. From day 5 to 35, G. candidum accounted for the largest proportion of CDS reads, suggesting that this species was the most active. Only minor changes occurred in the transcriptomes of the lactic acid bacteria. For the two yeasts, we compared the expression of genes involved in the catabolism of lactose, galactose, lactate, amino acids, and free fatty acids. During ripening, genes involved in ammonia assimilation and galactose catabolism were down-regulated in the two species. Genes involved in amino acid catabolism were up-regulated in G. candidum from day 14 to day 35, whereas in D. hansenii, they were up-regulated mainly at day 35, suggesting that this species catabolized the cheese amino acids later. In addition, after 35 days of ripening, there was a down-regulation of genes involved in the electron transport chain, suggesting a lower cellular activity. The present study has exemplified how metatranscriptomic analyses provide insight into the activity of cheese microbial communities for which reference genome sequences are available. In the future, such studies will be facilitated by the progress in DNA sequencing technologies and by the greater availability of the genome sequences of cheese microorganisms.

MicroRNA-711 is a prognostic factor for poor overall survival and has an oncogenic role in breast cancer

MicroRNAs are important in cancer development and progression. In the present study, the clinical significance and function of microRNA-711 (miR-711) expression in breast cancer were investigated. The expression level of miR-711 was analyzed in breast cancer tissue samples using reverse transcription-quantitative polymerase chain reaction. Cell proliferation, colony formation, apoptosis and Transwell assays were performed in breast cancer cell lines transfected with miR-711 mimics or inhibitors, or control sequence. miR-711 was found to be upregulated in 30 formalin-fixed paraffin-embedded breast cancer tissue samples compared with paired non-cancerous breast tissues (P<0.05). Furthermore, a higher miR-711 expression was demonstrated to be associated with poor overall and disease-free survival times in 161 breast cancer patients, and miR-711 was identified as an independent prognostic factor using multivariate Cox regression analysis. In vitro, overexpression of miR-711 resulted in a significant increase in proliferation, colony formation, migration and invasion of breast cancer cells. By contrast, downregulating miR-711 inhibited cell proliferation, colony formation, migration and invasion and enhanced the rate of apoptosis of breast cancer cells. To the best of our knowledge, the present study is the first to demonstrate that miR-711 is an independent prognostic factor and serves an important oncogenic function in breast cancer, suggesting that miR-711 is a potential biomarker of prognosis and a molecular therapeutic target in breast cancer.

Evaluation of Appropriate Reference Genes for Reverse Transcription-Quantitative PCR Studies in Different Tissues of a Desert Poplar via Comparision of Different Algorithms

Despite the unshakable status of reverse transcription-quantitative PCR in gene expression analysis, it has certain disadvantages, including that the results are highly dependent on the reference genes selected for data normalization. Since inappropriate endogenous control genes will lead to inaccurate target gene expression profiles, the validation of suitable internal reference genes is essential. Given the increasing interest in functional genes and genomics of Populus euphratica, a desert poplar showing extraordinary adaptation to salt stress, we evaluated the expression stability of ten candidate reference genes in P. euphratica roots, stems, and leaves under salt stress conditions. We used five algorithms, namely, ΔC_t, NormFinder, geNorm, GrayNorm, and a rank aggregation method (RankAggreg) to identify suitable normalizers. To support the suitability of the identified reference genes and to compare the relative merits of these different algorithms, we analyzed and compared the relative expression levels of nine P. euphratica functional genes in different tissues. Our results indicate that a combination of multiple reference genes recommended by GrayNorm algorithm (e.g., a combination of Actin, EF1α, GAPDH, RP, UBQ in root) should be used instead of a single reference gene. These results are valuable for research of gene identification in different P. euphratica tissues.

The DEAD-box protein Dbp2 functions with the RNA-binding protein Yra1 to promote mRNP assembly

Eukaryotic gene expression involves numerous biochemical steps that are dependent on RNA structure and ribonucleoprotein (RNP) complex formation. The DEAD-box class of RNA helicases plays fundamental roles in formation of RNA and RNP structure in every aspect of RNA metabolism. In an effort to explore the diversity of biological roles for DEAD-box proteins, our laboratory recently demonstrated that the DEAD-box protein Dbp2 associates with actively transcribing genes and is required for normal gene expression in Saccharomyces cerevisiae. We now provide evidence that Dbp2 interacts genetically and physically with the mRNA export factor Yra1. In addition, we find that Dbp2 is required for in vivo assembly of mRNA-binding proteins Yra1, Nab2, and Mex67 onto poly(A)+ RNA. Strikingly, we also show that Dbp2 is an efficient RNA helicase in vitro and that Yra1 decreases the efficiency of ATP-dependent duplex unwinding. We provide a model whereby messenger ribonucleoprotein (mRNP) assembly requires Dbp2 unwinding activity and once the mRNP is properly assembled, inhibition by Yra1 prevents further rearrangements. Both Yra1 and Dbp2 are conserved in multicellular eukaryotes, suggesting that this constitutes a broadly conserved mechanism for stepwise assembly of mature mRNPs in the nucleus.

Cocaine represses protein phosphatase-1Cβ through DNA methylation and Methyl-CpG Binding Protein-2 recruitment in adult rat brain

Repeated cocaine exposure induces epigenetic factors such as DNA methyl-binding proteins, indicating that resulting changes in gene expression are mediated by alterations in brain DNA methylation. While the activity of protein phosphatase type-1 (PP1) is involved in cocaine effects and in brain plasticity, the expression of the PP1Cβ catalytic subunit gene was identified here as modulated by cocaine. Its expression was induced together with that of PP1Cγ in the brain of Methyl-CpG Binding Protein-2 (Mecp2) mutant mice, whereas PP1Cα expression was not affected, illustrating a different regulation of PP1C isoforms. Repeated cocaine administration was found to increase DNA methylation at the PP1Cβ gene together with its binding to Mecp2 in rat caudate putamen, establishing a link between two genes involved in cocaine-related effects and in learning and memory processes. Cocaine also increased DNMT3 expression, resulting in PP1Cβ repression that did not occur in the presence of DNMT inhibitor. Cocaine-induced PP1Cβ repression was observed in several brain structures, as evaluated by RT-qPCR, immunohistochemistry and Western blot, but did not occur after a single cocaine injection. Our data demonstrate that PP1Cβ is a direct MeCP2-target gene in vivo. They suggest that its repression may participate to behavioral adaptations triggered by the drug.