Stable Transfected Cell Lines Research Articles

Buyang Huanwu decoction promotes angiogenesis after cerebral ischemia through modulating caveolin-1-mediated exosome MALAT1/YAP1/HIF-1α axis

BackgroundAngiogenesis is an effective method for promoting neurological function recovery after cerebral ischemia (CI). Buyang Huanwu decoction (BHD) is a traditional Chinese medicinal recipe that is frequently employed for CI treatment. Previous investigations have validated that it promotes angiogenesis following CI. Nevertheless, the precise mechanism by which it does this has yet to be completely understood. ObjectiveThis study aims to examine the underlying mechanism through which BHD facilitates angiogenesis following CI by regulating the exosomal MALAT1/YAP1/HIF-1α signaling axis, specifically via the involvement of caveolin-1 (Cav1), an endocytosis-associated protein. MethodsA CI model was created using middle cerebral artery occlusion (MCAO). Following the administration of multiple doses of BHD, various parameters, including the neurobehavioral score, pathological damage, and angiogenesis, were assessed in each group of mice to identify the optimal dosage of BHD for treating CI. The molecular processes underlying the angiogenic implications of BHD following CI were investigated exhaustively by employing single-cell sequencing. Finally, the involvement of Cav1 was confirmed in Cav1 knockout mice and Cav1-silenced stably transfected strains to validate the mechanism by which BHD increases angiogenesis following CI. ResultsBHD could promote angiogenesis after CI. Single-cell sequencing results suggested that its potential mechanism of action might be connected with Cav1 and the exosomal MALAT1/YAP1/HIF-1α signaling axis. BHD could promote angiogenesis after CI by regulating the exosomal MALAT1/YAP1/HIF-1α axis through Cav1, as validated in vivo and in vitro experiments. Accordingly, Cav1 may be a key target of BHD in promoting angiogenesis after CI. ConclusionThis investigation represents the initial attempt to comprehensively ascertain the underlying mechanism of action of BHD in treating CI using single-cell sequencing, gene-knockout mice, and stable transfected cell lines, potentially associated with the modulation of the exosomal MALAT1/YAP1/HIF-1α axis by Cav1. Our findings offer novel empirical evidence for unraveling the regulatory pathways through which Cav1 participates in angiogenesis following CI and shed light on the potential mechanisms of BHD.

Knockdown of NR3C1 inhibits the proliferation and migration of clear cell renal cell carcinoma through activating endoplasmic reticulum stress–mitophagy

BackgroundClear cell renal cell carcinoma (ccRCC) is closely associated with steroid hormones and their receptors affected by lipid metabolism. Recently, there has been growing interest in the carcinogenic role of NR3C1, the sole gene responsible for encoding glucocorticoid receptor. However, the specific role of NR3C1 in ccRCC remains unclear. The present study was thus developed to explore the underlying mechanism of NR3C1’s carcinogenic effects in ccRCC.MethodsExpression of NR3C1 was verified by various tumor databases and assessed using RT-qPCR and western blot. Stable transfected cell lines of ccRCC with NR3C1 knockdown were constructed, and a range of in vitro and in vivo experiments were performed to examine the effects of NR3C1 on ccRCC proliferation and migration. Transcriptomics and lipidomics sequencing were then conducted on ACHN cells, which were divided into control and sh-NR3C1 group. Finally, the sequencing results were validated using transmission electron microscopy, mitochondrial membrane potential assay, immunofluorescence co-localization, cell immunofluorescent staining, and Western blot. The rescue experiments were designed to investigate the relationship between endoplasmic reticulum stress (ER stress) and mitophagy in ccRCC cells after NR3C1 knockdown, as well as the regulation of their intrinsic signaling pathways.ResultsThe expression of NR3C1 in ccRCC cells and tissues was significantly elevated. The sh-NR3C1 group, which had lower levels of NR3C1, exhibited a lower proliferation and migration capacity of ccRCC than that of the control group (P < 0.05). Then, lipidomic and transcriptomic sequencing showed that lipid metabolism disorders, ER stress, and mitophagy genes were enriched in the sh-NR3C1 group. Finally, compared to the control group, ER stress and mitophagy were observed in the sh-NR3C1 group, while the expression of ATF6, CHOP, PINK1, and BNIP3 was also up-regulated (P < 0.05). Furthermore, Ceapin-A7, an inhibitor of ATF6, significantly down-regulated the expression of PINK1 and BNIP3 (P < 0.05), and significantly increased the proliferation and migration of ccRCC cells (P < 0.05).ConclusionsThis study confirms that knockdown of NR3C1 activates ER stress and induces mitophagy through the ATF6-PINK1/BNIP3 pathway, resulting in reduced proliferation and migration of ccRCC. These findings indicate potential novel targets for clinical treatment of ccRCC.Graphical

HLA DQ protein changes the cell surface distribution pattern of HLA proteins as monitored by Förster resonance energy transfer and high-resolution electron microscopy.

Peptide presentation by MHC class I and MHC class II molecules plays important roles in the regulation of the immune response. One factor in these displays is the density of antigen, which must exceed a critical threshold for the effective activation of T cells. Nonrandom distribution of MHC class I and class II has already been detected at the nanometer level and at higher hierarchical levels. It is not clear how the absence and reappearance of some protein molecules can influence the nonrandom distribution. Therefore, we performed experiments on HLA II-deficient bare lymphocyte syndrome (BLS1) cells: we created a stable transfected cell line, tDQ6-BLS-1, and were able to detect the effect of the appearance of HLA-DQ6 molecules on the homo and heteroassociation of different cell surface molecules by comparing Förster resonance energy transfer (FRET) efficiency on transfected cells to that on nontransfected BLS-1 and JY human B-cell lines. Our FRET results show a decrease in homoassociation FRET between HLA I chains in HLA-DQ6-transfected tDQ6-BLS-1 cells compared with the parent BLS-1 cell line and an increase in heteroassociation FRET between HLA I and HLA II (compared with JY cells), suggesting a similar pattern of antigen presentation by the HLA-DQ6 allele. Transmission electron microscopy (TEM) revealed that both HLA class I and class II molecules formed clusters at higher hierarchical levels on the tDQ6-BLS-1 cells, and the de novo synthesized HLA DQ molecules did not intersperse with HLA class I islands. These observations could be important in understanding the fine tuning of the immune response.

Identification of Biological Functions and Prognostic Value of NNMT in Oral Squamous Cell Carcinoma.

Background: Nicotinamide N-methyltransferase (NNMT) is a metabolic enzyme that catalyzes the methylation of nicotinamide (NAM) to generate 1-methyl nicotinamide (MNAM). Although previous studies have shown that NNMT is frequently dysregulated to promote the onset and progression of many malignancies, its expression profile, prognostic value and function in oral squamous cell carcinoma (OSCC) are still unknown. Methods: We used untargeted metabolomics based on mass spectrometry to analyze potential metabolite differences between tumors and matched adjacent normal tissues in 40 OSCC patients. Immunohistochemistry (IHC) was used to analyze the NNMT expression profile in OSCC, and the diagnostic and prognostic values of NNMT were evaluated. Next, qPCR and Western blot were used to compare the expression of NNMT in five OSCC cell lines. Stable transfected cell lines were constructed, and functional experiments were carried out to elucidate the effects of NNMT on the proliferation and migration of OSCC cells. Finally, gene set enrichment analysis (GSEA) was performed using The Cancer Genome Atlas (TCGA) data to investigate the potential functional mechanisms of NNMT in OSCC. Results: We found that the nicotinamide metabolic pathway was abnormally activated in OSCC tumor tissues compared with normal tissues. NNMT was expressed ubiquitously in tumor cells (TCs) and fibroblast-like cells (FLCs) but was absent in tumor-infiltrating lymphocytes (TILs). OSCC patients with highly expressed NNMT in TCs had higher risk of lymph node metastasis and showed a worse pattern of invasion (POI). Moreover, patients with highly expressed NNMT were also susceptible to postoperative recurrence. Highly expressed NNMT can independently predict shorter disease-free survival and recurrence-free survival. Functionally, we demonstrated that the ectopic expression of NNMT promoted OSCC tumor cell proliferation and migration in vitro. Conversely, silencing exerted significantly opposite effects in vitro. In addition, GSEA showed that highly expressed NNMT was mainly enriched in the epithelial–mesenchymal transformation (EMT) pathway, which displayed a significant positive correlation with the six classic EMT markers. Conclusions: Our study uncovered that NNMT may be a critical regulator of EMT in OSCC and may serve as a prognostic biomarker for OSCC patients. These findings might provide novel insights for future research in NNMT-targeted OSCC metastasis and recurrence therapy.

CMaf-Inducing Protein Promotes LUAD Proliferation and Metastasis by Activating the MAPK/ERK Pathway.

Objective Previous studies have shown that cMaf-inducing protein (CMIP) promotes tumorigenesis and progression, however, the role of CMIP in lung adenocarcinoma (LUAD) and its molecular mechanism remain unclear. Methods In this study, the Human Protein Atlas and Kaplan–Meier Plotter database were used to analyze the expression and prognostic value of CMIP in LUAD. Then, the expression levels of CMIP in LUAD tissues and cells were detected by qRT-PCR and western blot. The lentiviral vector was used to establish a stable transfected cell line, and the transfection efficiency was detected by qRT-PCR. MTT assay, colony formation assay, transwell assay, and wound healing assay were used to evaluate the function of CMIP in LUAD. In addition, the effect of CMIP on the MAPK/ERK pathway in LUAD cells was analyzed by western blot. Results The expression level of CMIP was significantly increased in LUAD cell and tissue samples, and the high expression of CMIP was associated with overall survival (OS) and progression-free survival (PFS) in LUAD patients. In vitro experiments showed that CMIP overexpression significantly promoted the proliferation, migration, and invasion of A549 cells. CMIP knockout significantly inhibited the proliferation, migration, and invasion of H1299 cells. In addition, it was observed that the expression levels of the MAPK/ERK pathway-related proteins were significantly increased in CMIP-overexpressed A549 cells, and promoted cell proliferation, migration, and invasion, while U0126 could significantly reverse the activation of the MAPK/ERK pathway by CMIP overexpression, and inhibit the proliferation, migration, and invasion of A549 cells. Conclusion Our study shows that CMIP, as an oncogene, is associated with poor patient prognosis, and may promote the proliferation and metastasis of LUAD by activating the MAPK/ERK pathway. Therefore, CMIP may be a new potential therapeutic target for LUAD.

NEK2 promotes the progression of liver cancer by resisting the cellular senescence.

Liver cancer is the sixth most common malignant tumor in the world. Hepatocellular carcinoma (HCC) accounts for 85%-90% of all patients with liver cancer. It possesses the characteristics of insidious onset, rapid progression, early recurrence, easy drug resistance, and poor prognosis. NIMA related kinase 2 (NEK2) is a cell cycle regulating kinases, which regulates cell cycle in mitosis. Cellular senescence is a complex heterogeneous process, and is a stable form of cell cycle arrest that limits the proliferative potential of cells. This study aims to investigate the relationship between the expression level of NEK2 and the senescence in hepatoma cells, and to explore the effect of NEK2 expression on hepatoma cell senescence and the underlying molecular mechanism. A total of 581 senescence-relevant genes were obtained from the GenAge website. The gene expression data of tumor tissues of 370 HCC patients were downloaded from the Cancer Genome Atlas database. The co-expression of NEK2 and aging-related genes was analyzed by R-package. KEGG was used to analyze the significant gene enrichment pathway of differentially expressed genes in NEK2 overexpression HEK293. The stable transfected cell lines with overexpression and knockdown of NEK2 were constructed in hepatoma cell line SMMC-7721 and HepG2, and senescence-associated β-galactosidase (SA-β-gal) staining was used to detect senescence, the cell proliferation was detected by CCK-8 method and clone formation experiment, the cell cycle was analyzed by flow cytometry, and the expression of proteins related to p53/p21, p16/Rb, and phosphatase and tensin homolog deleted on chromosome ten (PTEN)/Akt signal transduction pathway was detected by Western blotting. There were 320 senescence related genes co-expressed with NEK2. KEGG analysis showed that the senescence signaling pathway was significantly enriched in HEK293 cells with overexpression of NEK2.Compared with SMMC-7721 or HepG2 without knockdown of NEK2, the senescent cells of SMMC-7721 and HepG2 with knockdown of NEK2 were increased, cell proliferation and clone formation were decreased significantly, the percentage of cells in G0/G1 phase was increased, the expression levels of phospho-Akt (p-Akt) and phospho-Rb (p-Rb) protein were decreased significantly, and the expression level of p16 protein was increased significantly (all P<0.05). Compared with SMMC-7721 or HepG2 transfected with blank plasmid, the senescent cells of SMMC-7721 and HepG2 overexpressing NEK2 were decreased, the cell proliferation and clone formation were increased significantly, the percentage of cells in G0/G1 phase were decreased, the expression levels of p-Akt and p-Rb protein were increased significantly, and the expression level of p16 protein was decreased significantly (all P<0.05). NEK2 may mediate the anti-aging effect of hepatoma cells through p16/Rb and PTEN/Akt signal transduction pathways, which provides a new theoretical basis for NEK2 to promote the progress of liver cancer and a new idea for the targeting treatment for liver cancer.

Study of lncRNA TPA in Promoting Invasion and Metastasis of Breast Cancer Mediated by TGF-β Signaling Pathway.

PurposeThis study was to investigate the effects of lncRNA TPA overexpression and knockdown in stable transfected cell lines on the EMT, migration and invasion capabilities of breast cancer cells.MethodsWB and qRT-PCR were used to detect the expression of E-cadherin, Vimentin, fibronectin and N-cadherin, the key molecules of EMT, to determine whether lncRNA regulates EMT; scratch, migration and invasion assay were used to detected the effect of lncRNA TPA on the migration and invasion of breast cancer cells. The effect of lncRNA TPA on breast cancer metastasis was observed in nude mice model. Pierce Magnetic RNA-Protein Pull-Down Kit was used to bind the 3′-terminal desulfurized biotin-labeled lncRNA TPA with Magnetic beads, and then incubated with the proteins extracted from cell line C and D, respectively. After elution of the binding proteins, the interacting proteins were further identified by mass spectrometry to screen out the interacting proteins. The candidate proteins were expressed and purified in vitro, and the interaction between lncRNA-candidate proteins were verified by RNA-EMSA.ResultsOverexpression of lncRNA TPA decreased the expression of E-cadherin, and significantly increased the expression of Vimentin, fibronectin and TGF-β1 (p < 0.01), and increased the migration rate, migration ability and invasion ability of cell group (P < 0.01). Multiple lung metastases were observed in the lung tissue of nude mice with overexpression of lncRNA TPA.ConclusionLncRNA TPA affects the occurrence of breast cancer EMT through TGF-β signaling pathway, and then promotes the invasion and metastasis of breast cancer. LncRNA TPA may affect the corresponding signaling pathways through one or more interacting proteins, and ultimately promote the invasion and metastasis of breast cancer.

ARID1B/SUB1-activated lncRNA HOXA-AS2 drives the malignant behaviour of hepatoblastoma through regulation of HOXA3.

It has been becoming increasingly evident that long non‐coding RNAs (lncRNAs) play important roles in various human cancers. However, the biological processes and clinical significance of most lncRNAs in hepatoblastoma (HB) remain unclear. In our previous study, genome‐wide analysis with a lncRNA microarray found that lncRNA HOXA‐AS2 was up‐regulated in HB. Stable transfected cell lines with HOXA‐AS2 knockdown or overexpression were constructed in HepG2 and Huh6 cells, respectively. Our data revealed knockdown of HOXA‐AS2 increased cell apoptosis and inhibited cell proliferation, migration and invasion in HB. Up‐regulation of HOXA‐AS2 promoted HB malignant biological behaviours. Mechanistic investigations indicated that HOXA‐AS2 was modulated by chromatin remodelling factor ARID1B and transcription co‐activator SUB1, thereby protecting HOXA3 from degradation. Therefore, HOXA‐AS2 positively regulates HOXA3, which might partly demonstrate the involvement of HOXA3 in HOXA‐AS2‐mediated HB carcinogenesis. In conclusion, HOXA‐AS2 is significantly overexpressed in HB and the ARID1B/HOXA‐AS2/HOXA3 axis plays a critical role in HB tumorigenesis and development. These results might provide a potential new target for HB diagnosis and therapy.

Development of a CRISPR/Cas9 system in Entamoeba histolytica: proof of concept

The protozoan parasite Entamoeba histolytica is an important human pathogen and a leading parasitic cause of death on a global scale. The lack of molecular tools for genome editing hinders the study of important biological functions of this parasite. Due to its versatility, the CRISPR (clustered regularly interspaced short palindromic repeat)-Cas9 system has been successfully used to induce site-specific genomic alterations, including in protozoan parasites. In this study, we optimised CRISPR-Cas9 for use as a genetic tool in E. histolytica. We chose a single plasmid approach containing both guide RNA (gRNA) and Cas9 nuclease expression cassettes. The amebic U6 promoter was used to drive the expression of the gRNA and its expression was confirmed by Northern blot analysis. Stable transfectant cell lines were obtained using a destabilising domain of dihydrofolate reductase fused to myc-tagged Cas9 (ddCas9). With this system, we were able to induce ddCas9 expression 16 h following treatment with the small molecule ligand trimethoprim (TMP). Stable cell lines expressing ddCas9 and Luc-gRNA or non-specific (NS)-gRNA were transiently transfected with a plasmid containing a mutated luciferase gene (pDeadLuc) targeted by Luc-gRNA and another plasmid with a truncated luciferase gene (pDonorLuc) to restore luciferase expression and consequent activity. We observed that luminescence signal increased for the cell line expressing Luc-gRNA, suggesting that homologous recombination was facilitated by Cas9 activity. This evidence is supported by the presence of chimeric DNA detected by PCR and confirmed by sequencing of the resulting repaired DNA obtained by homologous recombination. We believe this represents the first report of a CRISPR/Cas9 system use in Entamoeba and provides evidence that this genome editing approach can be useful for genetic studies in this early branching eukaryote.

Chinese herbal formula QHF inhibits hepatocellular carcinoma metastasis via HGF/c-Met signaling pathway

Hepatocellular Carcinoma (HCC) is one of the most common malignant tumors, and high recurrence and metastasis are the major obstacles to successful treatment of HCC. Traditional Chinese medicine has little known and unique advantages in the treatment of HCC. Previous studies have confirmed that Chinese herbal formula Qingrejiedu (clears away heat and toxins), Huoxuehuayu (promotes blood flow to remove stasis) and Fuzhengguben (strengthens healthy qi and root) (QHF) has a significant effect on patients with advanced HCC, improves the quality of life and prolongs the survival time of patients significantly. In this study, we investigated the effect of QHF on proliferation, migration and invasion of human high metastatic hepatocellular carcinoma cell line HCCLM3 and its underlying mechanism. The results from our in vitro experiments showed that QHF has the ability to inhibit the proliferation by inducing G2/M phase cell cycle arrest and induce apoptosis. Moreover, QHF can also inhibit migration and invasion of HCCLM3 cells and the expression of the p-c-Met protein in HCCLM3 cells was down-regulated. c-Met is closely related to the metastasis of HCC, then we constructed a stable transfected cell line HepG2-met with high expression of c-Met by transfection. Further study in vivo revealed that c-Met gene will promote the growth of tumors and lung metastases in nude mice, and QHF intervention can reduce tumor lung metastases by inhibiting the HGF/c-Met signaling pathway. In conclusion, our study reveals that QHF can inhibit the proliferation, migration and invasion of HCCLM3, and this effect may be related to inhibiting HGF/c-Met signaling pathway.

Small-molecule PD-L1 inhibitor BMS1166 abrogates the function of PD-L1 by blocking its ER export

ABSTRACT Therapeutic monoclonal antibodies against the PD-L1/PD-1 (programmed death ligand-1/programmed cell death protein-1) axis have achieved great successes in cancer treatments, but the development of small-molecule immunomodulators of the pathway has lagged far behind. We established a cellular coculture assay with two stable transfectant cell lines, a PD-L1-expressing tumor cell line PC9/PD-L1 and a PD-1-expressing T cell line Jurkat/PD-1. Western blotting analyses were used to monitor the PD-L1/PD-1 interaction and signaling. We analyzed PD-L1 glycosylation by lectin binding assay and glycosidase digestion, and examined subcellular localization of PD-L1 by immunocytochemical staining. Luciferase assay and real-time PCR were used to evaluate T cell activation in the coculture experiments. We found that coculturing of the PC9/PD-L1 cells with the Jurkat/PD-1 cells induced a lysosomal degradation of PD-1. A small-molecule PD-L1 inhibitor BMS1166 developed by Bristol-Myers Squibb inhibited the coculture-induced PD-1 degradation through a unique mechanism. BMS1166 specifically affected PD-L1 glycosylation and prevented transporting of the under-glycosylated form of PD-L1 from endoplasmic reticulum (ER) to Golgi, leading to accumulation of PD-L1 in ER. In doing so, BMS1166 blocked PD-L1/PD-1 signaling. Coculturing PD-L1-expressing cells with PD-1-expressing cells induced degradation of PD-1, which could be used as a readout to identify inhibitors of PD-L1/PD-1 signaling. The small-molecule PD-L1 inhibitor BMS1166 abolished the glycosylation and maturation of PD-L1 by blocking its exporting from ER to Golgi. Our study discovered a new strategy to identify inhibitors of the PD-L1/PD-1 signaling pathway and to develop new drugs for the treatment of cancer.

Anti-oral Squamous Cell Carcinoma Effects of a Potent TAZ Inhibitor AR-42.

Oral squamous cell carcinoma (OSCC) is one of the most common malignancies worldwide. Although great progress has been made in diagnosis and treatment strategies in recent years, the 5-year survival rate of OSCC patients is still disappointingly low. Hence, there is still an unmet medical need for sufferers with OSCC. As a downstream effector of Hippo pathway, TAZ was up-regulated in multiple cancers including OSCC, and considered as an effective therapeutic target. In this study, we constructed a stable transfected cell line HEK293-TAZ to screen TAZ inhibitor using dual-luciferase reporter assay, and found a potential TAZ inhibitor AR-42. The results showed that AR-42 effectively suppressed the viability and proliferation of OSCC cells, and induced cellular apoptosis and cell cycle arrest in G2/M phase. Moreover, AR-42 potently inhibited cell invasion and the capacity of sphere-forming, as well as the expression of EMT and cancer stem cell related proteins in OSCC cells, exhibiting potential efficacy against OSCC metastasis and self-renewal of oral cancer stem cell. Further mechanism studies showed that AR-42 inhibited the total amount of TAZ and its paralog YAP mainly through blockade of TAZ/YAP transcription and promotion of TAZ/YAP protein degradation. Additionally, the inhibitory effect of AR-42 against TAZ, as well as its anti-OSCC activity could be also observed in SCC9 xenograft model. Taken together, AR-42 deserves to be further studied as a TAZ inhibitor, and is worthy to be further assessed as a potential drug candidate for OSCC treatment.

Research on the establishment of a TPM3 monoclonal stable transfected PANC-1 cell line and the experiment of the EMT occurrence in human pancreatic cancer.

Background: Pancreatic cancer is one of the most aggressive human malignancies that is associated with early metastasis and chemoresistance. Tropomyosin (TPM) is an indispensable regulatory protein for muscle contraction, Abnormal expressions of TPM gene are closely related to the carcinogenesis and metastasis of malignant tumors.Purpose: In this experiment, a monoclonal stable transfected cell line was established by the knock-down of TMP3 expression in PANC-1 cells with the lentivirus method, and the impacts of the downregulated TPM3 gene expression on the EMT-related molecules and biological behaviors of PANC-1 cells were explored.Methods: Based on the TPM3 gene sequence, we designed the RNA interference sequence, constructed and screened out the recombinant plasmid segment TPM3-shRNA with the optimal silencing effect, and carried out lentivirus titer determination and packaging. The recombinant lentiviral interference vector LV-TPM3-shRNA was transfected into PANC-1 cells; the transfection efficiency was then evaluated to screen out the monoclonal stable transfected PANC-1 cell line with downregulated TPM3 expression. The qRT-PCR and Western blot were used to detect the changes in the gene- and protein-levels expressions of EMT-related transcription factors in the target cell line and to respectively test the variations of the invasion and proliferation capacities.Results: It is shown that the monoclonal stable transfected PANC-1 cell line with downregulated TPM3 expression was successfully established with the recombinant lentiviral vector. After knocking down the expression of TPM3 gene in PANC-1 cells, EMT occurred in the cells; the cell phenotype showed malignant transformation, and the in vitro biological behaviors of the cells (such as proliferation and invasion) were enhanced to different degrees.Conclusion: It is indicated that the TPM3 gene can be a potential target spot for the treatment of pancreatic cancer.

Construction of lentivirus-mediated mito-OGG1 gene overexpression and OGG1 gene knockdown model in 661W cells

Objective To construct and authenticate the lentiviral-mediated overexpression of mouse mitochondrial-targeted-8-oxoguanine DNA-glycosylase 1 (mito-OGG1) gene and the lentiviral-mediated short hairpin RNA (shRNA) down-regulation of OGG1 gene expression model in 661W cells. Methods Constructed the target plasmids, including pLenti-EF1a-EGFP-P2A-Puro-CMV-Mito-OGG1-3Flag (pLenti-OGG1-GFP) and pLKD-CMV-G&PR-U6-shRNA (pLKD-shRNA).293T cells were used to obtain green fluorescent protein (GFP)-tagged lentiviral vector of interest by using a second generation lentivirus packaging system.293T cells were also used for the virus titer estimation.The multiplicity of infection (MOI) of 661W cells was detected by fluorescence microscopy.A stable transfected cell line was screened by puromycin.Immunofluorescence was used to detect transfection efficiency and cytochrome C oxidase Ⅳ(COXⅣ)-OGG1 co-localization.OGG1 mRNA and protein expression levels were detected by real-time qantitative PCR (QPCR) and Western blot. Results Sequencing results showed that the inserted sequence in the over-expression plasmid was consistent with the mouse OGG1 (NM_010957.4) gene sequence in the gene library.The original lentiviral titer after packaging and purification was between 2.0×107 to 6.0×107 TU/ml.The optimal MOI of 661W cells was 40, and puromycin with a concentration of 4.0 μg/ml successfully screened stable transformation.The transfection efficiency was up to 100% after screening.Immunofluorescence demonstrated successful co-localization of OGG1 and COXⅣ.The relative expression levels of OGG1 mRNA in the blank control group, OGG1 group, overexpression control group, shRNA group and low expression control group were 1.000±0.000, 41.581±12.206, 0.888±0.056, 0.239±0.121 and 1.081±0.083, and the relative expression levels of OGG1 protein were 1.029±0.153, 1.657±0.237, 0.752±0.143, 0.471±0.149 and 1.036±0.185, respectively, with significant differences between them (F=44.654, 30.948; both at P<0.05), the relative expression levels of OGG1 mRNA and protein in the OGG1 group were significantly higher than those in the overexpression control group, the relative expression levels of OGG1 mRNA and protein in the shRNA group were significantly lower than those in the lower expression control group, with significant differences between them (all at P<0.05). Conclusions The mito-OGG1 overexpression and OGG1 knockdown models of 661W cells are successfully constructed, which provides the preliminary experimental basis for follow-up study. Key words: Lentivirus vector; Overexpression; Short hairpin RNA; OGG1 gene; 661W cell; Mitochondrial targeting sequence

Epithelial ovarian cancer stem‑like cells are resistant to the cellular lysis of cytokine‑induced killer cells via HIF1A‑mediated downregulation of ICAM‑1.

Epithelial ovarian cancer(EOC) is the most lethal of all gynecologic tumors. Cancer spheroid culture is a widely used model to study cancer stem cells. Previous studies have demonstrated the effectiveness of cytokine‑induced killer(CIK) cell‑based therapies against cancer and cancer stem cells. However, it is not clear how EOC spheroid cells respond to CIK‑mediated cellular lysis, and the mechanisms involved have never been reported before. A flow cytometry‑based method was used to evaluate the anti‑cancer effects of CIK cells against adherent A2780 cells and A2780 spheroids. To demonstrate the association between hypoxia inducible factor‑1α(HIF1A) and intercellular adhesion molecule‑1(ICAM‑1), two HIF1A short hairpin RNA(shRNA) stable transfected cell lines were established. Furthermore, the protein expression levels of hypoxia/HIF1A‑associated signaling pathways were evaluated, including transforming growth factor‑β1(TGF‑β1)/mothers against decapentaplegic homologs(SMADs) and nuclear factor‑κB(NF‑κB) signaling pathways, comparing A2780 adherent cells and cancer spheroids. Flow cytometry revealed that A2780 spheroid cells were more resistant to CIK‑mediated cellular lysis, which was partially reversed by an anti‑ICAM‑1 antibody. HIF1A was significantly upregulated in A2780 spheroids compared with adherent cells. Using HIF1A shRNA stable transfected cell lines and cobalt chloride, it was revealed that hypoxia/HIF1A contributed to downregulation of ICAM‑1 in A2780 spheroid cells and adherent cells. Furthermore, hypoxia/HIF1A‑associated signaling pathways, TGF‑β1/SMADs and NF‑κB, were activated in A2780 spheroid cells by using western blotting. The findings indicate that EOC stem‑like cells resist the CIK‑mediated cellular lysis via HIF1A‑mediated downregulation of ICAM‑1, which may be instructive for optimizing and enhancing CIK‑based therapies.

Construction of human ubiquitin specific peptidase 53 overexpressing cell line

Objective To construct an Esophageal cancer Eca109 cell line which can stably overexpressing the ubiquitin specific peptidase 53 (USP53). Methods The USP53 full-length gene was amplified by Polymerase Chain Reaction (PCR) using a plasmid containing the full-length sequence of USP53 purchased by GE. The constructed USP53 lentiviral plasmid and packaging plasmid were co-transfected into 293T cells to obtain concentrated lentiviral particles, and then the lentiviral particles were infected with Eca109 cells. The medium containing puromycin was selected for stable transfected cell lines. Results The mRNA expression of USP53 in overexpressing cell lines (45.070±0.942) was significantly higher than that in the control group (1.091±0.075) and the normal group (1.000±0.023). The difference was statistically significant (P<0.05), Western blotting showed that the expression of the tagged protein HA was significant expressed in the overexpressed cell line, and no tagged protein expression was observed in the control group and the normal group. Conclusion Human ubiquitin specific peptidase 53 overexpressing cell line was successfully constructed. Key words: Esophageal cancer; Eca109; Ubiquitin specific peptidase 53; Lentivirus

Evaluation of Possible Proarrhythmic Potency: Comparison of the Effect of Dofetilide, Cisapride, Sotalol, Terfenadine, and Verapamil on hERG and Native IKr Currents and on Cardiac Action Potential.

The proarrhythmic potency of drugs is usually attributed to the IKr current block. During safety pharmacology testing analysis of IKr in cardiomyocytes was replaced by human ether-a-go-go-related gene (hERG) test using automated patch-clamp systems in stable transfected cell lines. Aim of this study was to compare the effect of proarrhythmic compounds on hERG and IKr currents and on cardiac action potential. The hERG current was measured by using both automated and manual patch-clamp methods on HEK293 cells. The native ion currents (IKr, INaL, ICaL) were recorded from rabbit ventricular myocytes by manual patch-clamp technique. Action potentials in rabbit ventricular muscle and undiseased human donor hearts were studied by conventional microelectrode technique. Dofetilide, cisapride, sotalol, terfenadine, and verapamil blocked hERG channels at 37°C with an IC50 of 7 nM, 18 nM, 343 μM, 165 nM, and 214 nM, respectively. Using manual patch-clamp, the IC50 values of sotalol and terfenadine were 78 µM and 31 nM, respectively. The IC50 values calculated from IKr measurements at 37°C were 13 nM, 26 nM, 52 μM, 54 nM, and 268 nM, respectively. Cisapride, dofetilide, and sotalol excessively lengthened, terfenadine, and verapamil did not influence the action potential duration. Terfenadine significantly inhibited INaL and moderately ICaL, verapamil blocked only ICaL. Automated hERG assays may over/underestimate proarrhythmic risk. Manual patch-clamp has substantially higher sensitivity to certain drugs. Action potential studies are also required to analyze complex multichannel effects. Therefore, manual patch-clamp and action potential experiments should be a part of preclinical safety tests.

Exploration and characterization of a universal piggyBac transposon vector for efficient transgene studies in sheep

piggyBac (PB) is a DNA transposon that mediates transposition in various animal cells. As an efficient tool, PB transposons are applied to various transgenic research and optimized for different species, which is an essential means to enhance its versatility. To construct a universal PB transposase (PBase) vector for ovine transgene manipulation, the gene expression box of PBase with optimized bias for sheep codons was inserted into the pBNW-TP1 vector. The vector pBNW-TP2 with a single plasmid was successfully constructed. Then, pBNW-TP2 was transfected into ovine fibroblasts and mammary epithelial cells. The stable transfected cell lines were selected by G418 and the PB transposition sites were determined by Tail-PCR in the stable transfected cell lines. The transposition efficiency was verified by student's t-tests for cell clones with methylene blue staining. The results showed that pBNW-TP2 successfully guided the production of transgenic ovine fibroblasts and mammary epithelial cell lines. The PB transposition test indicated that the pBNW-TP2 vector can be specifically integrated into the TTAA sites of the sheep genome. The statistical analysis of methylene blue staining results suggested that the transgenic efficiency mediated by the pBNW-TP2 vector increased significantly. In summary, we verified and analyzed characteristics of the universal PB transposon vector pBNW-TP2 for sheep in this study, which will provide a scientific basis for future transgenic research mediated by the PB transposon in ovine somatic cells.

Assessment of Proinflammatory Mediators of Beta-Cell Circadian Clock Dysfunction in Diabetes

Both type 1 and type 2 diabetes are characterized by a decline in β-cell function and mass partly attributed to exposure of β-cells to proinflammatory cytokines. The molecular mechanisms underlying this process are not well understood, however several lines of evidence have linked the circadian clock with regulation of the deleterious proinflammatory effects in diabetes. Therefore, in this study, we assessed the effect of known proinflammatory mediators of β-cell failure in diabetes (IL-1β, TNFα, IL-6, and IFNγ) on the β-cell circadian clock. Through real-time bioluminescence tracking of islets from Per2:luciferase (a key circadian clock gene reporter) knock-in mice, our data revealed that IL-1β (2 ng/ml) diminished β-cell circadian rhythmicity via impairment of the amplitude and the phase of oscillations (p&amp;lt;0.vs. vehicle). This was in contrast to TNFα, IL-6, and IFNγ, which showed either mild suppression or no effect on the β-cell clock. We next assessed the ability of proinflammatory cytokines to modulate Bmal1 and Clock (two main transcription factors in the circadian pathway) gene and protein expression. Interestingly, studies using INS-1 832/13 cells and cadaveric human islets revealed that IL-1β addition (0.2-5 ng/ml) for 24 h significantly reduced Bmal1 (but not Clock) at both the mRNA (∼40-50%, p&amp;lt;0.05) and protein (10-65%, p&amp;lt;0.05) level in a dose dependent manner. In contrast, other cytokines (IL-6, TNFα, and IFNγ) only modestly diminished Bmal1 expression after 24 h. In assessing a molecular link between IL-1β and the β-cell clock, Bmal1 promoter activity was determined using a BMAL1:luciferase expressing INS-1 832/13 stable-transfected cell line. Importantly, IL-1β (0.01-5 ng/ml) showed a dose dependent decrease in Bmal1 promoter activation (up to 90%). This body of work provides the first novel connection between diabetogenic inflammatory cytokines, specifically IL-1β, as the dominant mediator of β-cell clock dysfunction in diabetes. Disclosure N. Javeed: None. K. Rakshit: None. A. Matveyenko: None.

Construction of human ARF4 lentiviral vector and stable expression in ovarian cancer cell line SKOV3

Objective To establish ovarian cancer cell line SKVO3 that can stably express human ADP ribosylation factor-4 (ARF4). Methods A eukaryotic expression vector pCDH-CMV-MCS-EF1-Puro/ARF4 was constructed and transfected into SKOV3 cells after verifying by DNA sequencing. The expression of ARF4 mRNA was verified by real-time quantitative PCR (qRT-PCR). Then, the recombinant plasmid with lentiviral packaging plasmids were co-transfected into SKOV3 cells for packaging. The recombinant lentiviral particles LV-ARF4 were collected and transfected into SKOV3 cells, and the stable transfected SKOV3 cell line was screening by culture with puromycin. The expression of ARF4 gene was detected by qRT-PCR and Western Blot. Results A eukaryotic expression vector pCDH-CMV-MCS-EF1-Puro/ARF4 was successfully constructed. The vector could significantly up-regulate the expression of ARF4 mRNA in SKOV3 cells and be successfully packaged into recombinant lentiviral particles in HEK-293T cells. Compared with the control group, the relative expression level of ARF4 mRNA and protein in SKOV3 cells was significantly increased after the infection with LV-ARF4 (all P<0.001). Conclusion The recombinant plasmid pCDH-CMV-MCS-EF1-Puro/ARF4 and lentiviral vector LV-ARF4 were successfully constructed. The establishment of stably infected SKOV3 cell line with LV-ARF4 provides an experimental foundation for further studies on the biological function of ARF4 in ovarian cancer. Key words: Gene cloning; Lentiviral vector; ADP-ribosylation factor 4; SKOV3 cell line