Synergistic promotion of transient transgene expression in CHO cells by PDI/XBP-1s co-transfection and mild hypothermia.

Transient gene expression system is an important tool for rapid production of recombinant proteins in Chinese hamster ovary (CHO) cells. However, their low productivity is the main hurdle to overcome. An effective approach through which to obtain high protein yield involves targeting transcriptional, post-transcriptional events (PTEs), and culture conditions. Here, we investigated the effects of protein disulfide isomerase (PDI) and spliced X-box binding protein 1 (XBP-1s) co-overexpression combined with mild hypothermia on the transient yields of recombinant proteins in CHO cells. The results showed that the gene of interest (GOI) and the PDI/XBP-1s helper vector at a co-transfection ratio of 10:1 could obviously increase transient expression level of recombinant protein in CHO cells. However, PDI/XBP-1s overexpression had no significance effect on the mRNA levels of the recombinant protein, suggesting that it targeted PTEs. Moreover, the increased production was due to the enhancing of cell specific productivity, not related to cell growth, viability, and cell cycle. In addition, combined PDI/XBP-1s co-overexpression and mild hypothermia could further improve Adalimumab expression, compared to the control/37 °C and PDI/XBP-1s/37 °C, the Adalimumab volume yield of PDI/XBP-1s/33 °C increased by 203% and 142%, respectively. Mild hypothermia resulted in 3.52- and 2.33-fold increase in the relative mRNA levels of PDI and XBP-1s, respectively. In conclusion, the combination of PDI/XBP-1s overexpression and culture temperature optimization can achieve higher transient expression of recombinant protein, which provides a synergetic strategy to improve transient production of recombinant protein in CHO cells.

Cytosolic Cadherin 4 promotes angiogenesis and metastasis in papillary thyroid cancer by suppressing the ubiquitination/degradation of ß-catenin.

BACKGROUND: Although the long-term prognosis of papillary thyroid cancer (PTC) is favorable, distant metastasis significantly compromises the prognosis and quality of life for patients with PTC. The Cadherin family plays a pivotal role in tumor metastasis; however, the involvement of Cadherin 4 (CDH4) in the metastatic cascade remains elusive. METHODS: The expression and subcellular localization of CDH4 were determined through immunohistochemistry, immunofluorescence, and western blot analyses. The impact of CDH4 on cell migration, invasion, angiogenesis, and metastasis was assessed using transwell assays, tube formation assays, and animal experiments. Immunoprecipitation assay and mass spectrometry were employed to examine protein associations. The influence of CDH4 on the subcellular expression of ß-catenin and active ß-catenin was investigated via western blotting and immunofluorescence. Protein stability and ubiquitination assay were employed to verify the impact of CDH4 on ß-catenin degradation. Rescue experiments were performed to ensure the significance of CDH4 in regulating nuclear ß-catenin signaling. RESULTS: CDH4 was found to be significantly overexpressed in PTC tissues and predominantly localized in the cytoplasm. Furthermore, the overexpression of CDH4 in tumor tissues is associated with lymph node metastasis in PTC patients. Cytosolic CDH4 promoted the migration, invasion, and lung metastasis of PTC cells and stimulated the angiogenesis and tumorigenesis of PTC; however, this effect could be reversed by Tegavivint, an antagonist of ß-catenin. Mechanistically, cytosolic CDH4 disrupted the interaction between ß-catenin and ß-TrCP1, consequently impeding the ubiquitination process of ß-catenin and activating the nuclear ß-catenin signaling. CONCLUSIONS: CDH4 induces PTC angiogenesis and metastasis via the inhibition of ß-TrCP1-dependent ubiquitination of ß-Catenin.

Intranasal B5 promotes mucosal defence against Actinobacillus pleuropneumoniae via ameliorating early immunosuppression.

Actinobacillus pleuropneumoniae (APP) is an important pathogen of the porcine respiratory disease complex, which leads to huge economic losses worldwide. We previously demonstrated that Pichia pastoris-producing bovine neutrophil ß-defensin-5 (B5) could resist the infection by the bovine intracellular pathogen Mycobacterium bovis. In this study, the roles of synthetic B5 in regulating mucosal innate immune response and protecting against extracellular APP infection were further investigated using a mouse model. Results showed that B5 promoted the production of tumour necrosis factor (TNF)-α, interleukin (IL)-1ß, and interferon (IFN)-ß in macrophages as well as dendritic cells (DC) and enhanced DC maturation in vitro. Importantly, intranasal B5 was safe and conferred effective protection against APP via reducing the bacterial load in lungs and alleviating pulmonary inflammatory damage. Furthermore, in the early stage of APP infection, we found that intranasal B5 up-regulated the secretion of TNF-α, IL-1ß, IL-17, and IL-22; enhanced the rapid recruitment of macrophages, neutrophils, and DC; and facilitated the generation of group 3 innate lymphoid cells in lungs. In addition, B5 activated signalling pathways associated with cellular response to IFN-ß and activation of innate immune response in APP-challenged lungs. Collectively, B5 via the intranasal route can effectively ameliorate the immune suppression caused by early APP infection and provide protection against APP. The immunization strategy may be applied to animals or human respiratory bacterial infectious diseases. Our findings highlight the potential importance of B5, enhancing mucosal defence against intracellular bacteria like APP which causes early-phase immune suppression.

Long non-coding RNA MEG3 acts as a suppressor in breast cancer by regulating miR-330/CNN1.

BACKGROUND: The current study aimed to investigate the molecular mechanism of long non-coding RNA (lncRNA) MEG3 in the development of breast cancer. METHODS: The regulating relationships among lncRNA MEG3, miRNA-330 and CNN1 were predicted by bioinformatics analysis of breast cancer samples in the Cancer Genome Atlas database. The differential expression of lncRNA MEG3, miRNA-330 and CNN1 was first validated in breast cancer tissues and cells. The effects of lncRNA MEG3 on breast cancer malignant properties were evaluated by manipulating its expression in MCF-7 and BT-474 cells. Rescue experiments, dual-luciferase assays, and RNA immunoprecipitation (RIP) experiments were further used to validate the relationships among lncRNA MEG3, miRNA-330 and CNN1. RESULTS: Bioinformatics analysis showed that lncRNA MEGs and CNN1 were significantly downregulated in breast cancer tissues, while miR-330 was upregulated. These differential expressions were further validated in our cohort of breast cancer samples. High expression levels of lncRNA MEG3 and CNN1 as well as low expression of miR-330 were significantly associated with favorable overall survival. Overexpression of lncRNA MEG3 significantly inhibited cell viability, migration and invasion, decreased cells in S stage and promoted cell apoptosis. Dual-luciferase reporter gene assay and RIP experiments showed that lncRNA MEG3 could directly bind to miR-330. Moreover, miR-330 mimics on the basis of lncRNA MEG3 overexpression ameliorated the tumor-suppressing effects of lncRNA MEG3 in breast cancer malignant properties by decreasing CNN1 expression. CONCLUSION: Our study indicated lncRNA MEG3 is a breast cancer suppressor by regulating miR-330/CNN1 axis.

Serum sex hormones correlate with pathological features of papillary thyroid cancer.

PURPOSE: Sex hormones are thought to be responsible for the unique gender differences in papillary thyroid cancer(PTC). Most previous studies on these have focused on the expression of estrogen receptors, or have been limited to animal studies. The aim of our study was to explore the relationship between serum sex hormones and the pathological features of PTC in the clinical setting, as further evidence of the role of sex hormones in PTC. METHODS: Retrospective data analysis of patients who underwent thyroid surgery at the Department of Thyroid Surgery, Nanjing Drum Tower Hospital from January 2022 to September 2022 Correlation between serum sex hormone and pathological features was analyzed in male patients and in menopausal female patients. Serum sex hormones include luteinizing hormone(LH), follicle stimulating hormone(FSH), estradiol(E2), total testosterone(TT), progesterone(P), and prolactin(PRL). Tumor pathological characteristics include the number and size of tumor, presence of extrathyroidal extension(ETE), presence of lymph node metastasis(LNM). RESULTS: Preoperative serum E2 in male patients was positively correlated with tumor size in PTC, LH was negatively correlated with LNM, while TT and P were negatively correlated with ETE. Similar findings were not observed in menopausal female patients. CONCLUSION: We observed that serum sex hormones correlate with the pathological features of PTC in male patients, for the first time in a clinical study. High serum estrogens may be a risk factor for PTC, while androgens are the opposite. This somewhat corroborates previous research and provides new variables for future PTC prediction models.

Development of an amoxicillin-radix scutellaria extract formulation and evaluation of its pharmacokinetics in pigs.

BACKGROUND: A new antibacterial compound powder of amoxicillin (AMO)/Radix Scutellaria extract (RSE) was developed, and its pharmacokinetics were determined in pigs following oral administration. RESULTS: The MIC ranges of AMO against Escherichia coli, Staphylococcus aureus and Streptococcus were 1-8 µg/mL, 0.5-4 µg/mL and 0.5-64 µg/mL, respectively. The MIC ranges of RSE against E. coli, S. aureus, and Streptococcus were greater than 2.5 mg/mL, 0.156-2.5 mg/mL, and greater than 2.5 mg/mL, respectively. For S. aureus, the combined drug susceptibility test showed that AMO and RSE had an additive or synergistic effect. The results of compatibility test, the excipient screening test and the drug quality control test showed that the formulation had stable quality and uniform properties under the test conditions. Two studies were conducted to investigate the pharmacokinetics of the compound product in pigs. First, the pharmacokinetics of the AMO-RSE powder were compared with those of their respective single products. The results showed no significant change in the main pharmacokinetic parameters when either component was removed from the compound formulation; thus, AMO and RSE have no pharmacokinetic interaction in pigs. Second, pigs were orally administered three different doses of AMO-RSE powder. The Cmax and AUC increased proportionally with increasing p.o. dose; thus, the λz, t1/2λ, MRT, and Tmax were unchanged for the doses of 10, 20, and 30 mg/kg AMO and the doses of 5, 10, and 15 mg/kg BCL, showing that AMO/baicalin in AMO-RSE powder showed linear pharmacokinetic characteristics in pigs. CONCLUSIONS: The combined drug sensitivity test of AMO and RSE against S. aureus showed that the combination was additive or synergistic. Pharmacokinetic studies indicated that AMO and BCL do not interfere with each other in pigs when used in a compound formulation. The pharmacokinetic parameters remained unchanged regardless of the dose for p.o. administration, indicating linear pharmacokinetic properties over the tested dose range. The quality of the AMO-RSE powder was good and stable, providing a foundation for its clinical application in veterinary medicine. Further bioavailability, PK/PD and clinical trials are still needed to determine the final dosage regimen.

Deciphering the map of METTL14-mediated lncRNA m6A modification at the transcriptome-wide level in breast cancer.

BACKGROUND: Emerging studies have demonstrated the critical role of RNA m6A methylation in tumor progression, whereas lncRNA m6A modification profiles in breast cancer remain largely unknown. Our previous study has shown that METTL14 accelerates breast cancer migration and invasion in an m6A-dependent manner, making it critical to analyze METTL14-mediated m6A modification at a transcriptome-wide scale in breast cancer. METHODS: Here, we performed MeRIP-seq analysis in METTL14 overexpressed and control MDA-MB-231 cells. Conjoint analysis of MeRIP-seq and RNA-seq data was used to select lncRNAs with m6A methylation and differential expression. Finally, the screened lncRNA was verified by MeRIP-PCR and its function was studied via transwell assay. RESULTS: Our results determined that high expression of METLL14 results in 3996 hypermethylation peaks from 3107 transcripts, and 4100 hypomethylation peaks from 2918 transcripts. Furthermore, conjoint analysis of MeRIP-seq and RNA-seq data identified 25 lncRNAs with discrepant methylation and simultaneously discrepant expression, among which the top 10 differentially expressed LncRNAs were AC026401.3, CYTOR, LINC01943, AC084125.2, FLJ20021, LINC00472, and NORAD, MALAT1, AL161431.1, and LINC01764. Moreover, over-expressed METTL14 stimulated the m6A modification of AC084125.2, while decreasing its expression. Compared to adjacent tissues, AC084125.2 was lowly expressed in tumors and could be used as a biomarker in the diagnosis of breast cancer. Meanwhile, AC084125.2 inhibited the migration and invasion of cancer cells. CONCLUSION: In conclusion, METTL14-mediated m6A modification of lncRNAs, which might provide reference for future intervention in tumor progression.

Preparation, Characterization and Pharmacokinetics of Tolfenamic Acid-Loaded Solid Lipid Nanoparticles.

The clinical use of nonsteroidal anti-inflammatory drugs is limited by their poor water solubility, unstable absorption, and low bioavailability. Solid lipid nanoparticles (SLNs) exhibit high biocompatibility and the ability to improve the bioavailability of drugs with low water solubility. Therefore, in this study, a tolfenamic acid solid lipid nanoparticle (TA-SLN) suspension was prepared by a hot melt-emulsification ultrasonication method to improve the sustained release and bioavailability of TA. The encapsulation efficiency (EE), loading capacity (LC), particle size, polydispersity index (PDI), and zeta potential of the TA-SLN suspension were 82.50 ± 0.63%, 25.13 ± 0.28%, 492 ± 6.51 nm, 0.309 ± 0.02 and -21.7 ± 0.51 mV, respectively. The TA-SLN suspension was characterized by dynamic light scattering (DLS), fluorescence microscopy (FM), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and Fourier transform infrared (FT-IR) spectroscopy. The TA-SLN suspension showed improved sustained drug release in vitro compared with the commercially available TA injection. After intramuscular administration to pigs (4 mg/kg), the TA-SLN suspension displayed increases in the pharmacokinetic parameters Tmax, T1/2, and MRT0-∞ by 4.39-, 3.78-, and 3.78-fold, respectively, compared with TA injection, and showed a relative bioavailability of 185.33%. Thus, this prepared solid lipid nanosuspension is a promising new formulation.

MTHFD1L knockdown diminished cells growth in papillary thyroid cancer.

Methylenetetrahydrofolate dehydrogenase (NADP+ dependent) 1 like (MTHFD1L) is a mitochondrial enzyme involved in the synthesis of tetrahydrofolate (THF). This study aimed to investigate the effect of MTHFD1L in papillary thyroid cancer (PTC). Tumor tissues and adjacent tissues from 11 patients with PTC were collected, the expression level of MTHFD1L mRNA was detected by quantitative real-time polymerase chain reaction (qRT-PCR). The cancer genome atlas (TCGA) database was used for analysis MTHFD1L differentially expressed between tumor tissue and adjacent tissues. MTHFD1L was knocked down by a lentivirus-based system and CRISPR-Cas9. Affymetrix genechip human transcriptome array 2.0 was used to assess gene expression. Cell growth and motility were evaluated in vivo and in vitro. Cell apoptosis and cell cycle were investigated by flow cytometry assay. The expression levels of proteins were detected by western blotting. MTHFD1L mRNA and protein expression levels significantly increased in tumor tissues and CAL-62, K1 and TPC-1 cell lines. After knockdown MTHFD1L, the growth of cells were reduced while cell apoptosis was increased. In addition, tumor growth was inhibited after MTHFD1L knockdown in nude mice. Affymetrix genechip human transcriptome array 2.0 was founded that MTHFD1L knockdown can inhibit the expression levels of CCND1 and Notch2. Furthermore, we identified that MTHFD1L knockdown inhibited cells growth and induced cell apoptosis in PTC. Importantly, MTHFD1L knockdown decreased the expression levels of Notch2, Hes1 CCND1, Bcl-2, and PCNA protein, whereas the level of Bax increased. Our study suggested MTHFD1L knockdown could diminished PTC cell proliferation. MTHFD1L serves as a valuable therapeutic target.

Long non-coding RNA anti-differentiation non-coding RNA affects proliferation, invasion, and migration of breast cancer cells by targeting miR-331.

We aimed to evaluate the effects of long-chain non-coding RNA (lncRNA) anti-differentiation non-coding RNA (ANCR) on the proliferation, invasion, and migration of breast cancer cells by targeting miR-331. Forty-eight breast cancer and paracancerous tissue samples were collected. LncRNA ANCR expressions in breast cancer and adjacent tissues, human breast cancer cells and mammary epithelial cells, and miR-331 expressions in interfering cell line MDA-MB-231 (MCF-7)-shANCR, negative control MDA-MB-231 (MCF-7)-shNC and blank control MDA-MB-231 (MCF-7) were detected by real-time quantitative PCR. The correlations between lncRNA ANCR expression and clinicopathological characteristics were analyzed. Cell proliferation was detected by MTT and colony formation assays. Invasion and migration were tested by Transwell and scratch assays, respectively. The targeting relationship between ANCR and miR-331 was analyzed using the TargetScan database, and their interaction was studied using a dual-luciferase reporter assay. The expression of lncRNA ANCR in breast cancer tissue was significantly lower than that in adjacent normal tissue (p < 0.05). LncRNA ANCR was lowly expressed in various human breast cancer cell lines, being lowest in high-metastatic cell line (MDA-MB-231HM) (p < 0.05). Silencing lncRNA ANCR significantly enhanced the proliferation and invasion capacities of breast cancer cells, and promoted their tumor formation abilities in nude mice (p < 0.05). ANCR bound miR-331 targetedly, and the former negatively regulated the expression of the latter. LncRNA ANCR is lowly expressed upon breast cancer, and inhibits cell proliferation, invasion, and migration in vitro and in vivo. LncRNA ANCR exerts antitumor effects by targetedly binding miR-331 and then inhibiting its expression.

Construction of an expression vector mediated by the dual promoter for prokaryotic and mammalian cell expression system.

The aim of this study was to construct an expression vector mediated by the dual promoter that can simultaneously drive the recombinant protein production in eukaryotic and prokaryotic cells. The prokaryotic T7 promoter and ribosome binding site (RBS) was cloned downstream of CMV promoter in the eukaryotic expression vector pIRES-neo, and T7 termination sequence was inserted upstream of neomycin phosphotransferase gene to generate the dual promoter vector. The enhanced green fluorescent protein (eGFP) gene was used as reporter gene. Then, the resultant vector was transfected into Chinese hamster ovary (CHO) cells and transformed into Escherichia coli (E. coli) BL21, and the eGFP expression levels were analyzed by fluorescence microscopy, flow cytometry and Western blot, respectively. Fluorescence microscopy revealed that the eGFP was expressed in both CHO cells and E. coli BL21. Flow cytometry showed that the eGFP expression level had no significant difference between the dual promoter vector and control vector in transfected CHO cells. Western blot analysis indicated the eGFP expressed in transformed E. coli. In conclusion, a prokaryotic-eukaryotic double expression vector was successfully constructed, which has potential applications in rapid cloning and expression of recombinant proteins in both prokaryotic and eukaryotic expression systems.

METTL14 promotes the migration and invasion of breast cancer cells by modulating N6­methyladenosine and hsa­miR­146a­5p expression.

Breast cancer (BC) is the most frequently diagnosed cancer and the leading cause of cancer­related death among women worldwide. Evidence indicates that posttranscriptional N6­methyladenosine (m6A) modification modulates BC development. In the present study, we assessed BC and normal tissues to investigate this connection. RNA m6A levels were determined by methylation quantification assay. The effects of methyltransferase­like 14 (METTL14) gain­of­expression or co­transfection with an m6A inhibitor on cell migration and invasion abilities were determined by Transwell assays. The levels of differentially expressed (DE) miRNAs were verified by real­time quantitative PCR (RT­qPCR). Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes analyses (KEGG) were performed to analyze potential function of target genes of the DE miRNAs. The effects of candidate miRNAs modulated by METTL14 on cell migration and invasion abilities were confirmed by Transwell assays. We demonstrated that m6A methyltransferase METTL14 was significantly upregulated in BC tissues compared with normal tissues. METTL14 gain­ and loss­of­expression regulated m6A levels in MCF­7 and MDA­MB­231 cells. The cell function assays revealed that METTL14 overexpression enhanced the migration and invasion capacities of BC cells. Moreover, treatment with the m6A inhibitor suppressed this enhanced cell migration and invasion. Additionally, aberrant expression of METTL14 reshaped the miRNA profile in BC cell lines. The remodeled DE miRNA/mRNA network was found to be most enriched in cancer pathways, and DE miRNAs were enriched in cell adhesion terms. hsa­miR­146a­5p modulated by METTL14 promoted cell migration and invasion. METTL14 modulates m6A modification and hsa­miR­146a­5p expression, thereby affecting the migration and invasion of breast cancer cells.

Effect of promoter, promoter mutation and enhancer on transgene expression mediated by episomal vectors in transfected HEK293, Chang liver and primary cells.

The episomal vector cannot integrate into the host cell chromosome, which has no potential risk in gene therapy. However, the low level of transgene expression driven by episomal vectors needs to be solved. In this study, we investigated the effects of enhancers, promoters and promoter variants on transgene expression levels driven by episomal vectors in HEK293, Chang liver and primary cells. Results showed that all eight cis-acting elements used could increase transfection efficiency and transient eGFP expression in transfected HEK293 and Chang liver cells. In stably transfected mammalian cells, the elongation factor-1 alpha (EF-1α) promoter and mutant-404 showed high and stable transgene expression. The mechanisms might be related to the type and quantity of transcription factor regulatory elements. Moreover, quantitative reverse transcription polymerase chain reaction analysis showed that mRNA expression levels were not directly proportional to protein expression levels. Furthermore, the EF-1α promoter conferred high transgene expression levels in primary cells, and the plasmid was also present in the episomal state. Taken together, these results provided valuable information for improving transgene expression with episomal vectors in mammalian cells.

Shortened nuclear matrix attachment regions are sufficient for replication and maintenance of episomes in mammalian cells.

Matrix attachment regions (MARs) can mediate the replication of vector episomes in mammalian cells; however, the molecular mode of action remains unclear. Here, we assessed the characteristics of MARs and the mechanism that mediates episomal vector replication in mammalian cells. Five shortened subfragments of ß-interferon MAR fragments were cloned and transferred into CHO cells, and transgene expression levels, presence of the gene, and the episomal maintenance mechanism were determined. Three shortened MAR derivatives (position 781-1320, 1201-1740, and 1621-2201) retained full MAR activity and mediated episomal vector replication. Moreover, the three shortened MARs showed higher transgene expression levels, greater efficiency in colony formation, and more persistent transgene expression compared with those of the original pEPI-1 plasmid, and three functional truncated MARs can bind to SAF-A MAR-binding protein. These results suggest that shortened MARs are sufficient for replication and maintenance of episomes in CHO cells.

Assessing concordance among human, in silico predictions and functional assays on genetic variant classification.

MOTIVATION: A variety of in silico tools have been developed and frequently used to aid high-throughput rapid variant classification, but their performances vary, and their ability to classify variants of uncertain significance were not systemically assessed previously due to lack of validation data. This has been changed recently by advances of functional assays, where functional impact of genetic changes can be measured in single-nucleotide resolution using saturation genome editing (SGE) assay. RESULTS: We demonstrated the neural network model AIVAR (Artificial Intelligent VARiant classifier) was highly comparable to human experts on multiple verified datasets. Although highly accurate on known variants, AIVAR together with CADD and PhyloP showed non-significant concordance with SGE function scores. Moreover, our results indicated that neural network model trained from functional assay data may not produce accurate prediction on known variants. AVAILABILITY AND IMPLEMENTATION: All source code of AIVAR is deposited and freely available at https://github.com/TopGene/AIvar. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Enhancing expression level and stability of transgene mediated by episomal vector via buffering DNA methyltransferase in transfected CHO cells.

Nonviral episomal vectors present attractive alternative vehicles for gene therapy applications. Previously, we have established a new type of nonviral episomal vector-mediated by the characteristic motifs of matrix attachment regions (MARs), which is driven by the cytomegalovirus (CMV) promoter. However, the CMV promoter is intrinsically susceptible to silencing, resulting in declined productivity during long-term culture. In this study, Chinese hamster ovary (CHO) cells and DNA methyltransferase-deficient (Dnmt3a-deficient) CHO cells were transfected with plasmid-mediated by MAR, or CHO cells were treated with the DNA methylation inhibitor 5-Aza-2'-deoxycytidine. Flow cytometry, plasmid rescue experiments, fluorescence in-situ hybridization (FISH), and bisulfite sequencing were performed to observe transgene expression, its state of existence, and the CpG methylation level of the CMV promoter. The results indicated that all DNA methylation inhibitor and methyltransferase deficient cells could increase transgene expression levels and stability in the presence or absence of selection pressure after a 60-generation culture. Plasmid rescue assay and FISH analysis showed that the vector still existed episomally after long-time culture. Moreover, a relatively lower CMV promoter methylation level was observed in Dnmt3a-deficient cell lines and CHO cells treated with 5-Aza-2'-deoxycytidine. In addition, Dnmt3a-deficient cells were superior to the DNA methylation inhibitor treatment regarding the transgene expression and long-term stability. Our study provides the first evidence that lower DNA methyltransferase can enhance expression level and stability of transgenes mediated by episomal vectors in transfected CHO cells.

Germline TP53 and MSH6 mutations implicated in sporadic triple-negative breast cancer (TNBC): a preliminary study.

BACKGROUND: Germline BRCA1/2 prevalence is relatively low in sporadic triple-negative breast cancer (TNBC). We hypothesized that non-BRCA genes may also have significant germline contribution to Chinese sporadic TNBC, and the somatic mutational landscape of TNBC may vary between ethnic groups. We therefore conducted this study to investigate germline and somatic mutations in 43 cancer susceptibility genes in Chinese sporadic TNBC. PATIENTS AND METHODS: Sixty-six Chinese sporadic TNBC patients were enrolled in this study. Germline and tumor DNA of each patient were subjected to capture-based next-generation sequencing using a 43-gene panel. Standard bioinformatic analysis and variant classification were performed to identify deleterious/likely deleterious germline mutations and somatic mutations. Mutational analysis was conducted to identify significantly mutated genes. RESULTS: Deleterious/likely deleterious germline mutations were identified in 27 (27/66, 40.9%) patients. Among the 27 patients, 9 (9/66, 13.6%) were TP53 carriers, 5 (5/66, 7.6%) were MSH6 carriers, and 5 (5/66, 7.6%) were BRCA1 carriers. Somatic mutations were identified in 64 (64/66, 97.0%) patients. TP53 somatic mutations occurred in most of the patients (45/66, 68.2%) and with highest mean allele frequency (28.1%), while NF1 and POLE were detected to have the highest mutation counts. CONCLUSIONS: Our results supported our hypotheses and suggested great potentials of TP53 and MSH6 as novel candidates for TNBC predisposition genes. The high frequency of somatic NF1 and POLE mutations in this study showed possibilities for clinical benefits from androgen-blockade therapies and immunotherapies in Chinese TNBC patients. Our study indicated necessity of multi-gene testing for TNBC prevention and treatment.

Poultry biogas slurry can partially substitute for mineral fertilizers in hydroponic lettuce production.

Poultry biogas slurry, a by-product of the biogas production process, is rich in nutrients. However, improper handling increases the potential for serious environmental contamination and resource waste. The preparation of nutrient solutions for hydroponic lettuce production requires large amounts of mineral fertilizers, which provides an opportunity for poultry biogas slurry to enter the crop nutrient cycle. To assess the feasibility of the application of poultry biogas slurry, we used different proportions of biogas slurry and mineral fertilizers in a hydroponics experiment with lettuce. Four treatments were established: HS (half-strength Hoagland solution), BS (2.6% biogas slurry), BS + HS (1.3% biogas slurry + quarter-strength Hoagland solution), and BS + MF (2.6% biogas slurry + mineral fertilizers). The addition of poultry biogas slurry (BS + HS) did not have an adverse effect on lettuce growth, significantly increased the soluble sugar concentration, reduced the nitrate concentration, and the concentrations of heavy metals were still within the safety standards. In addition, the application of poultry biogas slurry could effectively reduce the production costs, energy consumption, and greenhouse gas emissions of hydroponically grown lettuce. Based on our study, poultry biogas slurry could replace 50% of the mineral fertilizer used in hydroponic lettuce production. The key is to control the electrical conductivity and replenish the nutrients that are lacking in the biogas slurry, especially magnesium.

miR-381 overcomes cisplatin resistance in breast cancer by targeting MDR1.

Increasing evidence suggests the involvement of microRNA-381 (miR-381) in chemoresistance of cancer treatment. However, its function and molecular mechanisms in breast cancer chemoresistance are still not well elucidated. In the present study, we aimed to investigate the functional role of miR-381 in cisplatin (DDP) resistance of breast cancer and discover the underlying molecular mechanism. The expression levels of miR-381 and MDR1 were detected by quantitative real-time PCR (qRT-PCR) and Western blot analysis in breast cancer tissues and cell lines. The DDP sensitivity and cell apoptosis of breast cancer cells were determined by MTT assay and flow cytometric analysis, respectively. The relationship between miR-381 and MDR1 was explored by target prediction and luciferase reporter analysis. miR-381 was decreased in DDP-resistant breast cancer tissues and cell lines. Low miR-381 expression was correlated with poor prognosis of breast cancer patients. miR-381 overexpression improved DDP sensitivity of MCF-7/DDP and MDA-MB-231/DDP cells. Conversely, miR-381 inhibition lowered the response of MCF-7 and MDA-MB-231 to DPP. Moreover, miR-381 could directly suppress multidrug resistance 1 (MDR1) expression. MDR1 knockdown could overcome DDP resistance in MCF-7/DDP and MDA-MB-231/DDP cells, while MDR1 overexpression led to DDP resistance in MCF-7 and MDA-MB-231 cells. Notably, MDR1 overexpression counteracted the inductive effect of miR-381 mimics on DDP sensitivity of MCF-7/DDP and MDA-MB-231/DDP cells. On the contrary, miR-381 inhibition-mediated DDP resistance in MCF-7 and MDA-MB-231 cells was reversed by MDR1 knockdown. In summary, miR-381 could overcome DDP resistance of breast cancer by directly targeting MDR1, providing a novel therapeutic target for breast cancer chemoresistance.