Anoikis-related lncRNA signature predicts prognosis and is associated with immune infiltration in hepatocellular carcinoma.

Anoikis is a programmed cell death process triggered when cells are dislodged from the extracellular matrix. Numerous long noncoding RNAs (lncRNAs) have been identified as significant factors associated with anoikis resistance in various tumor types, including glioma, breast cancer, and bladder cancer. However, the relationship between lncRNAs and the prognosis of hepatocellular carcinoma (HCC) has received limited research attention. Further research is needed to investigate this potential link and understand the role of lncRNAs in the progression of HCC. We developed a prognostic signature based on the differential expression of lncRNAs implicated in anoikis in HCC. A co-expression network of anoikis-related mRNAs and lncRNAs was established using data obtained from The Cancer Genome Atlas (TCGA) for HCC. Cox regression analyses were conducted to formulate an anoikis-related lncRNA signature (ARlncSig) in a training cohort, which was subsequently validated in both a testing cohort and a combined dataset comprising the two cohorts. Receiver operating characteristic curves, nomograms, and decision curve analyses based on the ARlncSig score and clinical characteristics demonstrated robust predictive ability. Moreover, gene set enrichment analysis revealed significant enrichment of several immune processes in the high-risk group compared to the low-risk group. Furthermore, significant differences were observed in immune cell subpopulations, expression of immune checkpoint genes, and response to chemotherapy and immunotherapy between the high- and low-risk groups. Lastly, we validated the expression levels of the five lncRNAs included in the signature using quantitative real-time PCR. In conclusion, our ARlncSig model holds substantial predictive value regarding the prognosis of HCC patients and has the potential to provide clinical guidance for individualized immunotherapy. In this study, we obtained 36 genes associated with anoikis from the Gene Ontology and Gene Set Enrichment Analysis databases. We also identified 22 differentially expressed lncRNAs that were correlated with these genes using data from TCGA. Using Cox regression analyses, we developed an ARlncSig in a training cohort, which was then validated in both a testing cohort and a combined cohort comprising data from both cohorts. Additionally, we collected eight pairs of liver cancer tissues and adjacent tissues from the Affiliated Tumor Hospital of Nantong University for further analysis. The aim of this study was to investigate the potential of ARlncSig as a biomarker for liver cancer prognosis. The study developed a risk stratification system called ARlncSig, which uses five lncRNAs to categorize liver cancer patients into low- and high-risk groups. Patients in the high-risk group exhibited significantly lower overall survival rates compared to those in the low-risk group. The model's predictive performance was supported by various analyses including the receiver operating characteristic curve, nomogram calibration, clinical correlation analysis, and clinical decision curve. Additionally, differential analysis of immune function, immune checkpoint, response to chemotherapy, and immune cell subpopulations revealed significant differences between the high- and low-risk groups. Finally, quantitative real-time PCR validated the expression levels of the five lncRNAs. In conclusion, the ARlncSig model demonstrates critical predictive value in the prognosis of HCC patients and may provide clinical guidance for personalized immunotherapy.

Upregulation of TTK expression is associated with poor prognosis and immune infiltration in endometrial cancer patients.

BACKGROUND: Threonine and tyrosine kinase (TTK) is associated with invasion and metastasis in various tumors. However, the prognostic importance of TTK and its correlation with immune infiltration in endometrial cancer (EC) remain unclear. METHODS: The expression profile of TTK was analyzed using data from The Cancer Genome Atlas (TCGA) and the Clinical Proteome Cancer Analysis Consortium (CPTAC). TTK protein and mRNA levels were verified in EC cell lines. Receiver operating characteristic (ROC) curve analysis was used to evaluate the ability of TTK to distinguish between normal and EC tissues. K-M survival analysis was also conducted to evaluate the impact of TTK on survival outcomes. Protein‒protein interaction (PPI) networks associated with TTK were explored using the STRING database. Functional enrichment analysis was performed to elucidate the biological functions of TTK. TTK mRNA expression and immune infiltration correlations were examined using the Tumor Immune Estimation Resource (TIMER) and the Tumor-Immune System Interaction Database (TISIDB). RESULTS: TTK expression was significantly greater in EC tissues than in adjacent normal tissues. Higher TTK mRNA expression was associated with tumor metastasis and advanced TNM stage. The protein and mRNA expression of TTK was significantly greater in tumor cell lines than in normal endometrial cell lines. ROC curve analysis revealed high accuracy (94.862%), sensitivity (95.652%), and specificity (94.894%) of TTK in differentiating EC from normal tissues. K-M survival analysis demonstrated that patients with high TTK expression had worse overall survival (OS) and disease-free survival (DFS) rates. Correlation analysis revealed that TTK mRNA expression was correlated with B cells and neutrophils. CONCLUSION: TTK upregulation is significantly associated with poor survival outcomes and immune infiltration in patients with EC. TTK can serve as a potential biomarker for poor prognosis and a promising immunotherapy target in EC. Further investigation of the role of TTK in EC may provide valuable insights for therapeutic interventions and personalized treatment strategies.

Minichromosome maintenance protein family member 6 mediates hepatocellular carcinoma progression by recruiting UBE3A to induce P53 ubiquitination.

With limited therapeutic options for hepatocellular carcinoma (HCC), it is of great significance to investigate the underlying mechanisms and identifying tumor drivers. MCM6, a member of minichromosome maintenance proteins (MCMs), was significantly elevated in HCC progression and associated with poor prognosis. Knockdown of MCM6 significantly inhibited the proliferation and migration of HCC cells with the increased apoptosis ratio and cell cycle arrest, whereas overexpression of MCM6 induced adverse effects. Mechanistically, MCM6 could decrease the P53 activity by inducing the degradation of P53 protein. In addition, MCM6 enhanced the ubiquitination of P53 by recruiting UBE3A to form a triple complex. Furthermore, overexpression of UBE3A significantly rescued the P53 activation and suppression of malignant behaviors mediated by MCM6 inhibition. In conclusion, MCM6 facilitated aggressive phenotypes of HCC cells by UBE3A/P53 signaling, providing potential biomarkers and targets for HCC.

CRTC2 promotes paclitaxel resistance by inducing autophagy in ovarian cancer in part via the PI3K-AKT signaling axis.

Background: Ovarian cancer is the most malignant gynecological disease, which seriously threatens female physical and mental health. Paclitaxel is a first-line chemotherapy drug in the clinical treatment of ovarian cancer, but drug resistance has become an important factor affecting the survival of ovarian cancer patients. However, the main mechanism of chemotherapy resistance in ovarian cancer remains unclear. In this study, we analyzed the Integrated Gene Expression Database (GEO) dataset using comprehensive bioinformatics tools to provide new therapeutic strategies and search for prognostic targets for ovarian cancer. Methods: Ovarian cancer related genes were extracted from GSE18520 by bioinformatics method. Differentially expressed genes (DEGs) were obtained by differential analysis, and related genes and functions were elucidated. The key gene CRTC2 was identified by prognostic analysis. Immunohistochemistry was used to detect the expression of CRTC2 in chemotherapy-resistant and chemotherapy-sensitive ovarian cancer tissues. Functional analysis (cell assay) confirmed the role of CRTC2 in paclitaxel resistance. Autophagy related proteins were detected by Western blot. Autophagy flux analysis was performed using the GFP/RFP-LC3 adenovirus reporter. Results: A total of 3,852 DEGs were identified in the GEO microarray dataset. Key genes were screened by prognostic analysis. We found that CRTC2 was highly expressed in chemoresistant tissues of ovarian cancer. In 110 patients with ovarian cancer, high expression of CRTC2 was associated with poorer prognostic factors and shorter survival. At the same time, we found that CRTC2 can promote the proliferation and invasion ability of ovarian cancer cells. In addition, CRTC2 can affect the expression of PI3K, AKT, autophagic flux and sensitivity to paclitaxel chemotherapy in ovarian cancer. Conclusion: CRTC2 can affect autophagy partially through PI3K-AKT signaling pathway, and then affect the sensitivity of ovarian cancer to paclitaxel chemotherapy. CRTC2 may be a potential predictor or target for ovarian cancer therapy.

An immune-related signature for optimizing prognosis prediction and treatment decision of hepatocellular carcinoma.

BACKGROUND: An immune-related gene signature (IGS) was established for discriminating prognosis, predicting benefit of immunotherapy, and exploring therapeutic options in hepatocellular carcinoma (HCC). METHODS: Based on Immune-related hub genes and The Cancer Genome Atlas (TCGA) LIHC dataset (n = 363), an immune-related gene signature (IGS) was established by least absolute shrinkage and selection operator (LASSO) analysis. The prognostic significance and clinical implications of IGS were verified in International Cancer Genome Consortium (ICGC) and Chinese HCC (CHCC) cohorts. The molecular and immune characteristics and the benefit of immune checkpoint inhibitor (ICI) therapy in IGS-defined subgroups were analyzed. In addition, by leveraging the Cancer Therapeutics Response Portal (CTRP) and PRISM Repurposing datasets, we determined the potential therapeutic agents for high IGS-risk patients. RESULTS: The IGS was constructed based on 8 immune-related hub genes with individual coefficients. The IGS risk model could robustly predict the survival of HCC patients in TCGA, ICGC, and CHCC cohorts. Compared with 4 previous established immune genes-based signatures, IGS exhibited superior performance in survival prediction. Additionally, for immunological characteristics and enriched pathways, a low-IGS score was correlated with IL-6/JAK/STAT3 signaling, inflammatory response and interferon α/γ response pathways, low TP53 mutation rate, high infiltration level, and more benefit from ICI therapy. In contrast, high IGS score manifested an immunosuppressive microenvironment and activated aggressive pathways. Finally, by in silico screening potential compounds, vindesine, ispinesib and dasatinib were identified as potential therapeutic agents for high-IGS risk patients. CONCLUSIONS: This study developed a robust IGS model for survival prediction of HCC patients, providing new insights into integrating tailored risk stratification with precise immunotherapy and screening potentially targeted agents.

Significance of Spliceosome-Related Genes in the Prediction of Prognosis and Treatment Strategies for Lung Adenocarcinoma.

Background: The leading cause of cancer-related fatalities globally is lung cancer; lung adenocarcinoma (LUAD) is the most common histological type in it. The spliceosome plays an important role in a majority of malignancies. However, it is yet unclear how spliceosome-related genes affect patients with LUAD in terms of treatment course and prognosis. Methods: Spliceosome-related genes were assessed from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) database to obtain clinical information and gene expression in patients with LUAD. A spliceosome-related gene signature and prognostic model were constructed by using the least absolute shrinkage and selection operator (LASSO), time-dependent receiver operating characteristic (ROC), and nomogram. Immune infiltrate levels, mutation analysis, and pathway enrichment were predicted potential mechanisms of the signature by using single-sample gene set enrichment analysis (ssGSEA), Gene Set Cancer Analysis (GSCA) database, Kyoto Encyclopedia of Genes and Genomes (KEGG), and Gene Ontology (GO) database. Then, a protein-protein interaction (PPI) network and transcription factor- (TF-) hub gene and drug mining network were also established by Cytoscape software. Results: Firstly, we constructed a prognostic model for 11 spliceosome signature genes. Based on the prognostic risk score, we stratified patients with LUAD into high- and low-risk groups. The high- and low-risk groups were closely related to the OS, tumor immune infiltration level, immune checkpoint molecules, and tumor mutation burden (TMB) of LUAD patients. Based on PPI networks, we also predict relevant TF genes that may regulate signature prognostic genes. Finally, drugs including oxaliplatin, arsenic trioxide, cisplatin, and sunitinib were excavated for the treatment of the 11 spliceosome signature genes in LUAD patients. Conclusion: In conclusion, this study is the first to explore the importance of spliceosome-related genes in the prognosis and treatment of LUAD. Through our study, we have innovatively provided potential prognosis genes and new therapeutic drug targets for the treatment of LUAD patients.

Clinical Significance of Serum Biomarkers in Stage IV Non-Small-Cell Lung Cancer Treated with PD-1 Inhibitors: LIPI Score, NLR, dNLR, LMR, and PAB.

Background: To assess the prognostic value of pretreatment serum biomarkers in stage IV non-small-cell lung cancer (NSCLC) patients treated with PD-1 (programmed cell death protein 1) inhibitors and their value as a predictor of benefit. Methods: We performed a retrospective study including patients with stage IV NSCLC who were treated with anti-PD-1 drugs in first or advanced lines of therapy in the Affiliated Tumor Hospital of Nantong University. Serum biomarkers such as NLR, dNLR, LMR, PAB, ALB, and LIPI scores were calculated and analyzed in detail. Results: A total of 85 patients with stage IV NSCLC treated with PD-1 inhibitors in the first or advanced lines of therapy were included in this subject. According to the tumor response of PD-1-based treatment, ORR was 42.4% (36/85) and DCR was 68.2% (58/85). The median OS and PFS were 20.0 months and 7.0 months, respectively. The ROC curves showed that the serum biomarkers of NLR, dNLR, LDH, LMR, PAB, and ALB were significantly associated with overall survival and helped to determine the cut-off value. The multivariate Cox proportional hazard analyses for stage IV NSCLC patients treated with PD-1 inhibitors indicated that dNLR (P < 0.001) and ALB (P = 0.033) were independent prognostic indicators of PFS, while liver metastasis (P = 0.01), NLR (P = 0.01), dNLR (P = 0.001), and LMR (P = 0.006) were independent prognostic indicators of OS. Moreover, patients of the good LIPI group showed prolonged PFS and OS than those with intermediate/poor LIPI score (P < 0.001 and P = 0.006, respectively). Conclusions: Pretreatment dNLR is an independent prognostic indicator of both PFS and OS in stage IV NSCLC patients treated with PD-1 inhibitors. Pretreatment LIPI, combining dNLR > 3 and LDH>ULN, was correlated with worse outcome for stage IV NSCLC patients treated with ICI. High NLR, high dNLR, low LMR, and low ALB at baseline might be useful as an early predictive biomarker of benefit.

Based on the Development and Verification of a Risk Stratification Nomogram: Predicting the Risk of Lung Cancer-Specific Mortality in Stage IIIA-N2 Unresectable Large Cell Lung Neuroendocrine Cancer Compared With Lung Squamous Cell Cancer and Lung Adenocarcinoma.

Background: The purpose of this study is to predict overall survival (OS) and lung cancer-specific survival (LCSS) in patients with stage IIIA-N2 unresectable lung squamous cell cancer (LUSC), lung adenocarcinoma (LUAD), and large cell neuroendocrine cancer (LCNEC) by constructing nomograms and to compare risk and prognostic factors affecting survival outcomes in different histological subtypes. Methods: We included 11,505 unresectable NSCLC patients at stage IIIA-N2 between 2010 and 2015 from the Surveillance, Epidemiology, and End Results (SEER) database. Moreover, competition models and nomograms were developed to predict prognostic factors for OS and LCSS. Results: Analysis of the SEER database identified 11,505 NSCLC patients, of whom 5,559 (48.3%) have LUAD, 5,842 (50.8%) have LUSC, and 104 (0.9%) have LCNEC. Overall, both OS and LCSS were significantly better in stage IIIA-N2 unresectable LUAD than in LCNEC, while there was no statistically significant difference between LUSC and LCNEC. Age, gender, T stage, chemotherapy, and radiotherapy were significantly associated with OS rates in LUAD and LUSC. However, chemotherapy was the only independent factor for LCNEC (p < 0.01).From competitive risk models, we found that older age, larger tumors, non-chemotherapy and non-radiotherapy were associated with a increased risk of death from LUAD and LUSC. Unlike prognostic factors for OS, our study showed that both chemotherapy and radiotherapy were all LCNEC-specific survival factors for both LCSS and non-LCSS LCNEC. Conclusion: Our study reports that unresectable patients with stage IIIA-N2 LCNEC and LUSC have worse LCSS than LUAD. The study's first prognostic nomogram constructed for patients with unresectable stage IIIA-N2 NSCLC can accurately predict the survival of different histological types, which may provide a practical tool to help clinicians assess prognosis and stratify these prognostic risks to determine which patients should be given an optimized individual treatment strategy based on histology.

Joint Progressive and Coarse-to-Fine Registration of Brain MRI via Deformation Field Integration and Non-Rigid Feature Fusion.

Registration of brain MRI images requires to solve a deformation field, which is extremely difficult in aligning intricate brain tissues, e.g., subcortical nuclei, etc. Existing efforts resort to decomposing the target deformation field into intermediate sub-fields with either tiny motions, i.e., progressive registration stage by stage, or lower resolutions, i.e., coarse-to-fine estimation of the full-size deformation field. In this paper, we argue that those efforts are not mutually exclusive, and propose a unified framework for robust brain MRI registration in both progressive and coarse-to-fine manners simultaneously. Specifically, building on a dual-encoder U-Net, the fixed-moving MRI pair is encoded and decoded into multi-scale sub-fields from coarse to fine. Each decoding block contains two proposed novel modules: i) in Deformation Field Integration (DFI), a single integrated deformation sub-field is calculated, warping by which is equivalent to warping progressively by sub-fields from all previous decoding blocks, and ii) in Non-rigid Feature Fusion (NFF), features of the fixed-moving pair are aligned by DFI-integrated deformation field, and then fused to predict a finer sub-field. Leveraging both DFI and NFF, the target deformation field is factorized into multi-scale sub-fields, where the coarser fields alleviate the estimate of a finer one and the finer field learns to make up those misalignments insolvable by previous coarser ones. The extensive and comprehensive experimental results on both private and two public datasets demonstrate a superior registration performance of brain MRI images over progressive registration only and coarse-to-fine estimation only, with an increase by at most 8% in the average Dice.

MiR-448 suppresses cell proliferation and glycolysis of hepatocellular carcinoma through inhibiting IGF-1R expression.

Background: Microribonucleic acids (miRNAs) have been shown to play important roles in hepatocellular carcinoma (HCC) progression. MiR-448 has frequently been shown to be a tumor suppressor, and is abnormally expressed in HCC tumor tissues. However, little is known about the role of miR-448 in HCC development. In this article, the regulatory role of miR-448 on insulin-like growth factor 1 receptor (IGF-1R) in modulating hepatoma cell viability and glycolysis was investigated. Methods: The expression of miR-448 profiles in clinical tumor tissues and cell lines was examined using quantitative real-time polymerase chain reaction (qRT-PCR). HepG2 and Huh7 cells were transfected with miR-448 mimics, inhibitors, and scramble sequences. Cell viability and apoptosis were determined by a Cell Counting Kit-8 assay and a flow cytometry analysis. IGF-1R, a potential target of miR-448, was selected following a bioinformatic analysis, and the regulatory effects of miR-448 on IGF-1R expression was confirmed by luciferase reporter assay, qRT-PCR, and western blot. Glucose uptake, lactate production, and adenosine triphosphate (ATP) generation were detected by corresponding kits. Results: Decreased miR-448 expression was observed in both HCC patients' tumor tissues and hepatoma cells in vitro. The overexpression of miR-448 in HepG2 and Huh7 cells decreased cell viability and increased apoptosis. Additionally, the overexpression of miR-448 or the knockdown of IGF-1R lowered the level of glucose uptake, lactate production, and ATP generation, while the knockdown of miR-448 increased glycolysis. Further, aberrantly expressed miR-448 downregulated IGF-1R levels, while the inhibition of miR-448 resulted in the upregulation of IGF-1R in both HepG2 and Huh7 cells. In addition, miR-448 interacted with the wild-type 3'untranslated regions (3'UTRs) of IGF-1R, but had no effect on the mutant 3'UTRs. The expression of IGF-1R was increased in HCC patients' tumor tissues and serum, and was inversely correlated with miR-448 expression. Conclusions: The increased expression of miR-448 appears to downregulate the expression of IGF-1R by interacting with the 3'UTR in HCC progression. These findings highlight its role as a potential target for HCC therapy.

Competing endogenous RNA network for esophageal cancer progression.

BACKGROUND: Esophageal cancer (ESCA) constitutes one of the most common cancers worldwide. The identification of potential biomarkers is important to improving the diagnostic accuracy and treatment efficiency for patients with ESCA. In this study, we aimed to identify biomarkers related to ESCA progression through a comprehensive analysis of long non-coding RNAs (lncRNAs), microRNA (miRNAs), and mRNA expression profiles in ESCA. METHODS: Differentially expressed lncRNAs, miRNAs, and mRNAs (DElncRNAs, DEmiRNAs, and DEmRNAs, respectively) in ESCA samples compared with normal controls were obtained. A competing endogenous RNA (ceRNA) network consisting of interacting DElncRNAs, DEmiRNAs, and DEmRNAs was constructed using a combination of the miRCode and TargetScan databases. Relationships between RNAs in the ceRNA network and overall survival in patients with EC were explored through another independent ESCA dataset from The Cancer Genome Atlas. RESULTS: A total of 1,014 DElncRNAs, 3,677 DEmRNAs, and 35 DEmiRNAs were identified in ESCA samples compared with normal samples. Functional enrichment analysis indicated that the DEmRNAs were involved in cell activity, inflammatory response, and oxygen metabolism-related biological processes. A ceRNA network containing 5 DEmiRNAs, 582 DEmRNAs and 764 DElncRNAs was obtained. In the survival analysis, 39 genes were found to be significantly associated with overall survival in patients with EC, including GOLGA7, NFYB, TOP1, and TMTC3. CONCLUSIONS: Our study constructed a ceRNA network for ESCA for the first time, which will be helpful for the disease's diagnosis and treatment.

Phylogenetic insights into chroococcus-like taxa (Chroococcales, Cyanobacteria), describing Cryptochroococcus tibeticus gen. nov. sp. nov. and Limnococcus fonticola sp. nov. from Qinghai-Tibet plateau.

Several coccoid cyanobacterial strains, morphologically similar to typical characteristics of Chroococcus, from the Qinghai-Tibet Plateau were isolated and characterized using a polyphasic approach including morphological and molecular information. Morphological characteristics, the phylogeny based on 16S rRNA gene, and 16S-23S internal transcribed spacer secondary structures support establishing a novel Chroococcus-like genus, Cryptochroococcus gen. nov., as well as Limnococcus fonticola sp. nov. Limnococcus is phylogenetically included in Chroococcaceae and has irregularly arranged thylakoids. Therefore, it should no longer be a member of Merismopediaceae (Synechococcales). The phylogeny based on the 16S rRNA gene revealed that Chroococcus-associated genera were monophyletic.

Occurrence of Raphidiopsis raciborskii blooms in cool waters: Synergistic effects of nitrogen availability and ecotypes with adaptation to low temperature.

Raphidiopsis raciborskii is a diazotrophic and potentially toxic cyanobacterium. To date, this species has successfully invaded many regions from the tropics to sub-tropical and temperate regions, typically forming blooms at temperatures greater than 25 °C. However, there have been a few cases in which R. raciborskii blooms have occurred at low temperatures (below 15 °C), but its cause and mechanisms remain unclear. In this study, field investigations revealed that R. raciborskii blooms occurred at 10-15 °C in Lake Xihu, Yunnan, China. The biomass of R. raciborskii was found to be positively related to nitrate concentrations in this lake. Three strains of R. raciborskii, two isolated from Lake Xihu (CHAB 6611 and CHAB 6612) and one from Lushui Reservoir in central China (CHAB 3409), were used for growth experiments at 15 °C. The three strains exhibited genotypic (16S rRNA and ITS-L genes) and physiological differences in response to nitrogen concentrations at low temperature. The growth rates of strains CHAB 6611 and CHAB 6612 increased with nitrogen concentration while CHAB 3409 could not grow at 15 °C. Furthermore, the growth and phenotypic responses of CHAB 6611 and CHAB 6612 to nitrogen concentrations were different, despite the closer genetic relationship shared by these two strains. Thus, increased nitrogen concentration in water may enhance the biological availability and utilization of nitrogen by R. raciborskii, which is the external promoter, leading to improving the resistance of R. raciborskii to low temperature. The internal cause is the presence of ecotypes in R. raciborskii populations with adaptation to low temperature. With increasing global eutrophication, the distribution range of R. raciborskii as well as the scale of its blooms will increase. As such, the risk of exposure of aquatic biota and humans to cylindrospermopsin is also expected to increase.

Interspecific competition reveals Raphidiopsis raciborskii as a more successful invader than Microcystis aeruginosa.

As a successful invasive cyanobacterial species, Raphidiopsis raciborskii is distributed globally and shows a tendency to replace Microcystis aeruginosa in many subtropical and temperate waters, but the ecological traits that contribute to its invasiveness are still unclear. In this study, we found that R. raciborskii occurred in 149 sites in 42 lakes in eastern and central China and coexisted with M. aeruginosa at most sites. Based on field results, a combination of invasion and competition experiments using a biomass gradient to evaluate the invasiveness and competitiveness of R. raciborskii compared with M. aeruginosa was conducted. In invasive groups, both R. raciborskii and M. aeruginosa were shown to have positive specific growth rates, indicating that R. raciborskii could coexist with M. aeruginosa. Furthermore, R. raciborskii was shown to grow faster from invasion while M. aeruginosa reduced growth for invasion. In competitive groups, R. raciborskii reached a higher maximum biomass and grew longer than M. aeruginosa. The specific growth rate of R. raciborskii was not inhibited by M. aeruginosa biomass, whereas the growth of M. aeruginosa was inhibited by R. raciborskii biomass. It was shown during the whole experiment that R. raciborskii tended to replace M. aeruginosa to become dominant owing to its faster growth rate and the eventual decline in growth of M. aeruginosa. With an increase in biomass of M. aeruginosa, the vegetative cell size and filament length of R. raciborskii gradually increased. This study has demonstrated that the inherent invasive traits of R. raciborskii, size differences, niche differences, and relative fitness differences between R. raciborskii and M. aeruginosa are crucial reasons for the invasive success of R. raciborskii. Our results revealed the invasiveness and domination of R. raciborskii from a new perspective.

Toxicity-associated changes in the invasive cyanobacterium Cylindrospermopsis raciborskii in response to nitrogen fluctuations.

The cyanobacterium Cylindrospermopsis raciborskii is of particular concern due to its ability to fix nitrogen (N), sporadic bloom, potential toxicity and apparent invasiveness. However, the toxicity associated behavior and response of toxic C. raciborskii under N fluctuations in water have been poorly investigated. The present study initiated based on the field survey in which Cylindrospermopsis species was found to have a high fitness under nitrate concentrations fluctuating from 0.02 mg L-1 to 2.90 mg L-1 in Chinese freshwater lakes. Examination on the role of short-term N fluctuations was conducted in two C. raciborskii strains which were exposed to a range of N concentrations supplied in two patterns, namely one-time pattern and ten-time pattern in which the equal amount of N was divided into ten-time accretions. The results showed the growth of both strains were not vulnerable to the transient nutrient fluctuations. The toxic strain showed considerable toxicological flexibility with the highest yield of cylindrospermopsin (CYN) obtained in the absence of N and the lowest in full medium. Generally, larger amounts of total CYN were observed at lower N levels, indicating that N deficiency promoted the intracellular accumulation and simultaneously restrained the extracellular release of CYN. Furthermore, CYN production was significantly different in two N supply patterns. The maximum quotas of intracellular and extracellular CYN in one-time pattern were respectively 2.79-3.53 and 3.94-7.20 times higher compared to the ten-time pattern. To our knowledge, our results are the first evidence of toxicity variations of C. raciborskii to the impermanent N fluctuations, shedding new light on its toxicological plasticity.

Geosmin production and polyphasic characterization of Oscillatoria limosa Agardh ex Gomont isolated from the open canal of a large drinking water system in Tianjin City, China.

Taste and odor (T & O) episodes always cause strong effects on drinking water supply system. Luanhe River diversion into Tianjin City in China is an important drinking water resource. Massive growth of a benthic filamentous cyanobacterium with geosmin production in the open canal caused a strong earthy odor episode in Tianjin. On the basis of the morphological and molecular identification of this cyanobacterium as Oscillatoria limosa Agardh ex Gomont, the genetic basis for geosmin biosynthesis and factors influencing growth and geosmin production of O. limosa CHAB 7000 were studied in this work. A 2268-bp open reading frame, encoding 755 amino acids, was amplified and characterized as the geosmin synthase gene (geo), followed by a cyclic nucleotide-binding protein gene (cnb). Phylogenetic analysis implied that the evolution of the geosmin genes in O. limosa CHAB 7000 might involve a horizontal gene transfer event. Examination on the growth and geosmin production of O. limosa CHAB 7000 at different light intensities showed that the maximum geosmin production was observed at 10µmol photons m-2s-1, while the optimum growth was at 60µmol photons m-2s-1. Under three temperature conditions (15°C, 25°C, and 35°C), the maximum growth and geosmin production were observed at 25°C. Most amounts of geosmin were retained in cells during the growth phase, but high temperature and low light intensity increased the release of geosmin into the medium, implying that O. limosa CHAB 7000 had a high potential harm for the release of geosmin from its cells at these adverse conditions.

Inhibition of the growth of hepatocellular carcinoma cells through fibroblast growth factor 18 suppressed by miR-139.

Hepatocellular carcinoma (HCC) is a highly malignant tumor and one of the most common causes for human cancer-related deaths. Fibroblast growth factor 18 (FGF18) is overexpressed in many types of cancer, and is associated with cell proliferation, invasion and angiogenesis. miR-139 has recently been reported as a tumor suppressor in various types of cancer and it can regulate many tumor-related genes, however its association with FGF18 expression in HCC has not been reported and thus remains unknown. In the present study, to explore the potential regulation mechanism of miR-139 with FGF18 in HCC, HCC tissues and cell lines were used. The results revealed that FGF18 was highly expressed in HCC tissues and cells, however miR-139 was lowly expressed. FGF18 was demonstrated to be a direct target of miR-139. Furthermore, the suppressive effect of miR-139 on FGF18 and in turn on proliferation, apoptosis, invasion, migration and tumor-induced angiogenesis of HCC cells was investigated. FGF18 was suggested as a prognostic biomarker and therapeutic target in HCC patients and miR-139 may be a promising strategy used in HCC treatment via the suppression of FGF18.

Candidate miRNAs and pathogenesis investigation for hepatocellular carcinoma based on bioinformatics analysis.

The present study aimed to explore the mechanisms behind the development and progression of hepatocellular carcinoma (HCC) and identify information regarding HCC-related microRNAs (miRNAs) or marker genes for the gene therapy of HCC. Gene expression profile of GSE67882, generated from 4 hepatitis B virus infected HCC tissue samples (HCC group) and 8 chronic hepatitis B tissue samples with no fibrosis (control group) were downloaded from the Gene Expression Omnibus database. The differentially expressed miRNAs functional enrichment and pathway analyses of HCC were revealed, followed by transcription factor-miRNA interaction network construction and analyses. A total of 14 upregulated miRNAs and 16 downregulated miRNAs between HCC and control samples were obtained. Differentially expressed miRNAs were mainly involved in biological processes like the regulation of histone H3-K9 methylation, and the KEGG pathways in cancer map05200 demonstrates their involvement in cancer. A total of 3 outstanding regulatory networks of miRNAs: hsa-miR-15a, hsa-miR-125b and hsa-miR-122 were revealed. A total of 11 differentially expressed miRNAs including hsa-miR-146p-5b that regulated the marker genes of HCC were explored. miRNAs such as hsa-miR-15a, hsa-miR-125b, hsa-miR-122 and hsa-miR-146b-5p may be new biomarkers for the gene therapy of HCC. Furthermore, histone H3-K9 methylation and other pathways in cancer observed in the KEGG map05200 may be closely related with the development of HCC.

Bioinformatics analysis of gene expression alterations in microRNA­122 knockout mice with hepatocellular carcinoma.

Reduced microRNA (miR)­122 expression levels are frequently observed in hepatocellular carcinoma (HCC). The present study was conducted to investigate potential targets of miR­122 and determine the underlying regulatory mechanisms of miR­122 in HCC development. The public dataset GSE31731 was utilized, consisting of 8 miR­122 knockout (KO) mice (miR­122 KO) and 8 age­matched wild­type mice (WT group). Following data preprocessing, the differentially expressed genes (DEGs) were selected, followed by enrichment analysis. A protein­protein interaction (PPI) network was established, and a module network was further extracted. Combining the DEGs with microRNA targeting databases permitted the screening of the overlapping targets of miR­122. Furthermore, previously reported genes were screened out by literature mining. Transcription factors (TFs) of the targets were subsequently investigated. DEGs between miR­122 KO and WT groups were selected, including 713 upregulated and 395 downregulated genes. Of these, upregulated genes were enriched in cell cycle­associated processes [including nucleolar and spindle associated protein 1 (NUSAP1)], the cytokine­cytokine receptor interaction pathway [including C­X­C motif chemokine receptor 4 (CXCR4) and C­C motif chemokine receptor 2 (CCR2)], and the extracellular matrix­receptor interaction pathway [including integrin subunit alpha V (ITGAV)]. In addition, multiple overlapping targets were highlighted in the PPI network, including NUSAP1, CXCR4, CCR2 and ITGAV. Notably, CXCR4 and CCR2 were linked in module C, enriched in the cytokine­cytokine receptor interaction pathway. Furthermore, upregulated sex determining region Y­box 4 (SOX4) was identified as a TF. The results of the present study may provide a theoretical basis for further studies on the mechanisms of miR­122 in the development of HCC.

Reversal of multidrug resistance of hepatocellular carcinoma cells by metformin through inhibiting NF-κB gene transcription.

AIM: To interfere with the activation of nuclear factor-κB (NF-κB) with metformin and explore its effect in reversing multidrug resistance (MDR) of hepatocellular carcinoma (HCC) cells. METHODS: Expression of P-glycoprotein (P-gp) and NF-κB in human HepG2 or HepG2/adriamycin (ADM) cells treated with pCMV-NF-κB-small interference RNA (siRNA) with or without metformin, was analyzed by Western blot or fluorescence quantitative PCR. Cell viability was tested by CCK-8 assay. Cell cycle and apoptosis were measured by flow cytometry and Annexin-V-PE/7-AnnexinV apoptosis detection double staining assay, respectively. RESULTS: P-gp overexpression in HepG2 and HepG2/ADM cells was closely related to mdr1 mRNA (3.310 ± 0.154) and NF-κB mRNA (2.580 ± 0.040) expression. NF-κB gene transcription was inhibited by specific siRNA with significant down-regulation of P-gp and enhanced HCC cell chemosensitivity to doxorubicin. After pretreatment with metformin, HepG2/ADM cells were sensitized to doxorubicin and P-gp was decreased through the NF-κB signaling pathway. The synergistic effect of metformin and NF-κB siRNA were found in HepG2/ADM cells with regard to proliferation inhibition, cell cycle arrest and inducing cell apoptosis. CONCLUSION: Metformin via silencing NF-κB signaling could effectively reverse MDR of HCC cells by down-regulating MDR1/P-gp expression.