Transient Transfection Of Cells Research Articles

Optimizing high-yield production of SARS-CoV-2 soluble spike trimers for serology assays

The SARS-CoV-2 spike trimer is the primary antigen for several serology assays critical to determining the extent of SARS-CoV-2 exposure in the population. Until stable cell lines are developed to increase the titer of this secreted protein in mammalian cell culture, the low yield of spike protein produced from transient transfection of HEK293 cells will be a limiting factor for these assays. To improve the yield of spike protein and support the high demand for antigens in serology assays, we investigated several recombinant protein expression variables by altering the incubation temperature, harvest time, chromatography strategy, and final protein manipulation. Through this investigation, we developed a simplified and robust purification strategy that consistently yields 5 mg of protein per liter of expression culture for two commonly used forms of the SARS-CoV-2 spike protein. We show that these proteins form well-behaved stable trimers and are consistently functional in serology assays across multiple protein production lots.

LncRNA TP73-AS1 Regulates miR-21/PTEN Axis to Affect Cell Proliferation in Acute Myeloid Leukemia

Objective: TP73-AS1 has been reported as an overexpressed oncogenic lncRNA in several types of cancer. However, these analyses of The Cancer Genome Atlas data set revealed downregulation of TP73-AS1 in acute myeloid leukemia (AML). In this study, we aimed to study the molecular mechanism between TP73-AS1 and cell proliferation in AML. Methods: Bone marrow (BM) samples were obtained from 50 AML patients and 50 healthy controls. Cell transient transfections were performed to analyze gene interactions. Dual-luciferase reporter assay, quantitative polymerase chain reaction and Western blot were used to study the gene expressions. Cell proliferation was analyzed by CCK-8 method. Results: TP73-AS1 was confirmed to be downregulated in AML. TP73-AS1 was predicted to interact with miR-21, while overexpression of TP73-AS1 and miR-21 did not affect the expression of each other. Instead, overexpression of TP73-AS1 led to the upregulation of phosphatase and tensin homologue (PTEN), a downstream target of miR-21. Cell proliferation analysis showed that overexpression of TP73-AS1 and PTEN led to a decreased proliferation rate of AML cells. Overexpression of miR-21 played an opposite role and reduced the effects of overexpressing TP73-AS1 and PTEN. Conclusion: TP73-AS1 may regulate the miR-21/PTEN axis to affect cell proliferation in AML.

OR24-05 Identifying Regulatory Elements Within a Novel Enhancer of FSHB Containing Two PCOS-Associated Single Nucleotide Polymorphisms

Polycystic ovary syndrome (PCOS) is the most common cause of female infertility, affecting approximately 10 percent of women by Rotterdam criteria, and is comorbid with obesity, type II diabetes, hypertension, and non-alcoholic fatty liver disease. As twin studies reveal that genetics account for approximately 70% of PCOS risk, genome-wide association studies (GWAS) can provide powerful insight into PCOS etiology. PCOS GWAS studies from several populations identified a risk locus containing the FSHB gene, which encodes the beta subunit of follicle-stimulating hormone (FSH). As FSH supplementation can restore ovulation in some PCOS patients, deficient FSH signaling could be a causative factor of anovulation and potentially other facets of PCOS. Two of the lead single nucleotide polymorphisms (SNPs) in association with PCOS, rs11031005 and rs11031006, fall within a highly conserved genomic region in mammals. We hypothesized that the conserved region (~450 base pairs) enhances FSHB transcription, and that one or both PCOS-related SNPs alter its function. We have shown that the conserved region from both human and mouse can act as an enhancer of FSHB in LβT2 cells, an immortalized, mouse-derived, mature pituitary gonadotrope cell line, and that its function is altered by the rs11031006 minor allele through modification of an SF1 consensus site. As elimination of the SF1 site reduced but did not completely abolish the function of the enhancer, we continued our investigation to identify additional regulatory sites. Transient transfection of LβT2 cells revealed a possible role for the rs11031005 SNP in FSHB regulation, with the minor allele decreasing enhancer-mediated FSHB transcription. This effect may be due to decreased binding of an unidentified transcription factor, as gel shift revealed that the rs11031005 minor allele reduced the intensity of a binding complex. Using truncations and sliding deletions, we identified three additional putative transcription factor binding sites with consensus sequences for ZEB1, PTX1, and SMAD. To support a role for the conserved region as an enhancer in native chromatin, we assessed the histone status in LβT2 chromatin. Compared to the proximal Fshb promoter, the enhancer-specific marker, H3K4me1, was enriched near the conserved region. Neither promoter/enhancer markers of active (H3K27Ac) or repressed (H3K27me3) chromatin were enriched near the conserved region, although levels of both modifications were consistent with the Fshb proximal promoter. Overall, our data support the role of this conserved region as a novel regulator of FSHB/Fshb transcription and reveal a possible mechanism to explain the contribution of PCOS-associated SNPs through FSHB regulation.

Next-generation transfection reagent for large scale AAV manufacturing

Background & Aim The number of ATMP therapeutic-based medicines for inherited genetic disorders is in constant growth, with a global 32% increase in new clinical trials in the last 4 years. ATMPs have demonstrated their success with already more than ten approved for commercialization. The success of AAV as the most promising viral vector for gene therapy is due to low immunogenicity, broad tropism and non-integrating properties. One major challenge for translation of promising research to clinical development is the manufacture of sufficient quantities of AAV. Methods, Results & Conclusion Transient transfection of suspension cells is the most commonly used production platform, as it offers significant flexibility for cell and gene therapy development. However, this method shows some limitations in large scale bioreactors: inadequate transfection protocol, reduced transfection efficiency and lower productivity. To address this concern, we present data on the novel transfection reagent showing: i) increased AAV titers, ii) improved transfection protocol for large scale bioreactors and iii) reproducibility of viral titers at different production scale. The aforementioned optimized parameters make this novel transfection reagent ideal for cell and gene therapy developers by combining the flexibility of transient transfection with scalability and speed to market. The number of ATMP therapeutic-based medicines for inherited genetic disorders is in constant growth, with a global 32% increase in new clinical trials in the last 4 years. ATMPs have demonstrated their success with already more than ten approved for commercialization. The success of AAV as the most promising viral vector for gene therapy is due to low immunogenicity, broad tropism and non-integrating properties. One major challenge for translation of promising research to clinical development is the manufacture of sufficient quantities of AAV. Transient transfection of suspension cells is the most commonly used production platform, as it offers significant flexibility for cell and gene therapy development. However, this method shows some limitations in large scale bioreactors: inadequate transfection protocol, reduced transfection efficiency and lower productivity. To address this concern, we present data on the novel transfection reagent showing: i) increased AAV titers, ii) improved transfection protocol for large scale bioreactors and iii) reproducibility of viral titers at different production scale. The aforementioned optimized parameters make this novel transfection reagent ideal for cell and gene therapy developers by combining the flexibility of transient transfection with scalability and speed to market.

Production of Vesicular Stomatitis Virus Glycoprotein-Pseudotyped Lentiviral Vector Is Enhanced by Ezrin Silencing.

Human immunodeficiency virus type 1 (HIV-1)-based viral vector is widely used as a biomaterial to transfer a gene of interest into target cells in many biological study fields including gene therapy. Vesicular stomatitis virus glycoprotein (VSV-G)-containing HIV-1 vector much more efficiently transduces various mammalian cells than other viral envelope proteins-containing vectors. Understanding the mechanism would contribute to development of a novel method of efficient HIV-1 vector production. HIV-1 vector is generally constructed by transient transfection of human 293T or African green monkey COS7 cells. It was found in this study that HIV-1 Gag protein is constitutively digested in lysosomes of African green monkey cells. Surprisingly, VSV-G elevated HIV-1 Gag protein levels, suggesting that VSV-G protects Gag protein from the lysosomal degradation. Unphosphorylated ezrin, but not phosphorylated ezrin, was detected in COS7 cells, and ezrin silencing elevated Gag protein levels in the presence of VSV-G. Expression of unphosphorylated ezrin reduced Gag protein amounts. These results indicate that unphosphorylated ezrin proteins inhibit the VSV-G-mediated stabilization of HIV-1 Gag protein. Trafficking of HIV-1 Gag-associated intracellular vesicles may be controlled by ezrin. Finally, this study found that ezrin silencing yields higher amount of VSV-G-pseudotyped HIV-1 vector.

CCL5 mediates target-kinase independent resistance to FLT3 inhibitors in FLT3-ITD-positive AML.

FLT3‐ITD tyrosine kinase inhibitors (TKI) show limited clinical activity in acute myeloid leukemia (AML) due to emerging resistance. TKI resistance is mediated by secondary FLT3‐ITD mutations only in a minority of cases. We hypothesize that the cytokine CCL5 protects AML cells from TKI‐mediated cell death and contributes to treatment resistance. We generated PKC412‐ and sorafenib‐resistant MOLM‐13 cell lines as an in vitro model to study TKI resistance in AML. Increased CCL5 levels were detected in supernatants from PKC412‐resistant cell lines compared to TKI‐sensitive cells. Moreover, CCL5 treatment of TKI‐sensitive cells induced resistance to PKC412. In resistant cell lines with high CCL5 release, we observed a significant downregulation of the CCL5‐receptor CCR5 and CXCR4. In these cell lines, TKI resistance could be partly overcome by addition of the CXCR4‐receptor antagonist plerixafor. Microarray and intracellular flow cytometry analyses revealed increased p‐Akt or p‐Stat5 levels in PKC412‐resistant cell lines releasing high amounts of CCL5. Treatment with the CXCR4 antagonist plerixafor, αCCL5, or CCR5‐targeting siRNA led to a decrease of p‐Akt‐positive cells. Transient transfection of sensitive MOLM‐13 cells with a CCL5‐encoding vector mediated resistance against PKC412 and led to an increase in p‐Akt‐positive and p‐Stat5‐positive cells. Isolated AML blasts from patients treated with PKC412 revealed that CCL5 transcript levels increase significantly at relapse. Taken together, our findings indicate that CCL5 mediates resistance to FLT3‐TKIs in FLT3‐ITD‐mutated AML and could possibly serve as a biomarker to predict drug resistance.

TGF-β1 fucosylation enhances the autophagy and mitophagy via PI3K/Akt and Ras-Raf-MEK-ERK in ovarian carcinoma

Transforming growth factor-β, a cell secretion factor of the TGF-β superfamily, is involved in the regulation of cell proliferation, differentiation, cytoskeleton formation, migration, invasion and other biological behaviors. Autophagy and mitophagy play an important role in tumor progression by regulating self-digestion, and degradation and reuse of cells and mitochondria. In this study, changes in autophagy and mitophagy processes in ovarian cancer cells under TGF-β1 treatment were detected via Western blot and immunofluorescence, as well as the role of fucosylation modification. Changes in mitochondrial membrane potential in response to TGF-β1 and fucosylation were detected via immunofluorescence. The effects of TGF-β1 and its fucosylation on autophagic flux were further determined by transient transfection of cells with Ad-mRFP-GFP-LC3 adenovirus. TGF-β1 clearly promoted autophagy and mitophagy in ovarian cancer cells. TGF-β1 fucosylation stimulated these regulatory effects on ovarian cancer cells via modulation of PI3K/Akt and Ras-Raf-MEK-ERK pathways through TAK1. Our collective data support the physiological significance of TGF-β1 and provide a novel direction for targeted therapy for ovarian cancer.

LncRNA GAS8-AS1 downregulates lncRNA UCA1 to inhibit osteosarcoma cell migration and invasion

BackgroundOsteosarcoma (OS) is the most common type of primary bone tumor that mainly affects adolescents and young adults. The present study explored the role of lncRNA GAS8-AS1 in OS.MethodsA total of 48 OS patients were selected from the 82 OS patients admitted by Luoyang Orthopedic Hospital of Henan Province between May 2010 and May 2013. Transient cell transfections, Transwell cell migration and invasion assay, RT-qPCR, and patient follow-up were carried out during the research.ResultsThe results showed that GAS8-AS1 was downregulated, while UCA1 was upregulate in cancer tissues in comparison to adjacent non-cancer tissues of OS patients. GAS8-AS1 was not affected by clinical stage. Follow-up study showed that downregulated GAS8-AS1 in cancer tissues was closely correlated with poor survival. GAS8-AS1 and UCA1 were inversely correlated in cancer tissues. Overexpression of UCA1 failed to affect the expression of GAS8-AS1, while overexpression of GAS8-AS1 led to downregulated expression of UCA1 in OS cells, while the molecular mediators between these two lncRNAs are unknown. Overexpression of GAS8-AS1 did not affect OS cell proliferation but significantly inhibited cancer cell migration and invasion. Overexpression of UCA1 promoted the migration and invasion of OS cells and attenuated the effects of overexpressing GAS8-AS1.ConclusionsTherefore, GAS8-AS1 may inhibit OS cell migration and invasion by downregulating oncogenic UCA1.

High-Throughput Screening Identifies Two Novel Small Molecule Enhancers of Recombinant Protein Expression.

As a primary strategy for production of biological drugs, recombinant proteins produced by transient transfection of mammalian cells are essential for both basic research and industrial production. Here, we established a high-throughput screening platform for improving the expression levels of recombinant proteins. In total, 10,011 small molecule compounds were screened through our platform. After two rounds of screening, we identified two compounds, Apicidin and M-344, that significantly enhanced recombinant protein expression. Both of the selected compounds were histone deacetylase inhibitors, suggesting that the two small molecules increased the expression levels of recombinant proteins by promoting histone acetylation. Moreover, both molecules showed low cytotoxicity. Therefore, our findings suggest that these small molecules may have wide applications in the future.

Recombinant mucin-type proteins carrying LacdiNAc on different O-glycan core chains fail to support H. pylori binding.

The β4-N-acetylgalactosaminyltransferase 3 (B4GALNT3) transfers GalNAc in a β1,4-linkage to GlcNAc forming the LacdiNAc (LDN) determinant on oligosaccharides. The LacdiNAc-binding adhesin (LabA) has been suggested to mediate attachment of Helicobacter pylori to the gastric mucosa via binding to the LDN determinant. The O-glycan core chain specificity of B4GALNT3 is poorly defined. We investigated the specificity of B4GALNT3 on GlcNAc residues carried by O-glycan core 2, core 3 and extended core 1 precursors using transient transfection of CHO-K1 cells and a mucin-type immunoglobulin fusion protein as reporter protein. Binding of the LabA-positive H. pylori J99 and 26695 strains to mucin fusion proteins carrying the LDN determinant on different O-glycan core chains and human gastric mucins with and without LDN was assessed in a microtiter well-based binding assay, while the binding of 125I-LDN-BSA to various clinical H. pylori isolates was assessed in solution. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) and western blotting confirmed the requirement of a terminal GlcNAc for B4GALNT3 activity. B4GALNT3 added a β1,4-linked GalNAc to GlcNAc irrespective of whether the latter was carried by a core 2, core 3 or extended core 1 chain. No LDN-mediated adhesion of H. pylori strains 26 695 and J99 to LDN determinants on gastric mucins or a mucin-type fusion protein carrying core 2, 3 and extended core 1 O-glycans were detected in a microtiter well-based adhesion assay and no binding of a 125I-labelled LDN-BSA neoglycoconjugate to clinical H. pylori isolates was identified.

Self-Assembled Nanoparticles Prepared from Low-Molecular-Weight PEI and Low-Generation PAMAM for EGFRvIII-Chimeric Antigen Receptor Gene Loading and T-Cell Transient Modification.

BackgroundThe complex preparation procedures and severe toxicities are two major obstacles facing the wide use of chimeric antigen receptor-modified T (CAR-T) cells in clinical cancer immunotherapy. The nanotechnology-based T cell temporary CAR modification may be a potential approach to solve these problems and make the CAR-T cell-based tumor therapy feasible and broadly applicable.MethodsA series of plasmid DNA-loaded self-assembled nanoparticles (pDNA@SNPsx/y) prepared from adamantane-grafted polyamidoamine (Ad-PAMAM) dendrimers of different generations (G1 or G5) and cyclodextrin-grafted branched polyethylenimine (CD-PEI) of different molecular weights (800, 2000, or 25,000 Da) were characterized and evaluated. The detailed physicochemical properties, cellular interaction, and cytotoxicity of selected pDNA@SNPG1/800 were systematically investigated. Thereafter, the epidermal growth factor receptor variant III (EGFRvIII) CAR-expression plasmid vector (pEGFRvIII-CAR) was constructed and encapsulated into SNPG1/800. The resulting pEGFRvIII-CAR@SNPG1/800 was used for Jurkat cell transient transfection, and the EGFRvIII-CAR expressed in transfected cells was measured by flow cytometry and Western blot. Finally, the response of EGFRvIII CAR-positive Jurkat T cell to target tumor cell was evaluated.ResultsThe pDNA@SNPG1/800 showed the highest efficacy in Jurkat cell gene transfection and exhibited low cytotoxicity. pEGFRvIII-CAR@SNPG1/800 can efficiently deliver pEGFRvIII-CAR into Jurkat T cells, thereby resulting in transient EGFRvIII-CAR expression in transfected cells. EGFRvIII-CAR that is present on the cell membrane enabled Jurkat T cells to recognize and bind specifically with EGFRvIII-positive tumor cells.ConclusionThese results indicated that pEGFRvIII-CAR@SNPG1/800 can effectively achieve T-cell transient CAR modification, thereby demonstrating considerable potential in CAR-T cancer therapy.

MYC regulates coelomocytes apoptosis by targeting Bax expression in sea cucumber Apostichopus japonicus

Myelocytomatosis viral oncogene (MYC), a multifunctional transcription factor, (TF) exerts various physiological and pathological effects on animals. AjMYC could induce coelomocyte apoptosis in Apostichopus japonicus, but the underlying molecular mechanism remains poorly understood. In this study, the promoter sequence of apoptosis regulator Bcl-2-associated X (Bax) was cloned by genomic walking. The AjBax promoter region spaning 1189 bp, containing several transcription factor binding sites, included four potential E-boxes (−1030 bp to −1019 bp, −785 bp to −774 bp, −570 bp to −559 bp, −100 bp to −89 bp), two P53 binding sites (−439 bp to −430 bp, −845 bp to −836 bp), and one NF-κB site (−191 bp to −182 bp). Transient transfection of EPC cells with 5′–deletion constructs linked to luciferase reporter revealed that the region −1189/+454 contributed importantly to the expression of the AjBax. In addition, the AjBax promoter was induced by LPS, PGN or MAN. The four potential MYC binding sites were cotransfected with AjMYC in EPC cell whether AjMYC could activate AjBax expression as a transcriptional factor. Only P1 (−1189/+454) fragment containing the first MYC binding site transfection increased the luciferase activity by 2.08-fold (p < 0.01) compared with the control. The first MYC binding site −1030/−1019 was essential to induce AjBax transcription. Further functional assay indicated that AjBax was significantly induced by 3.54-fold increase (p < 0.01) after AjMYC overexpression in sea cucumber coelomocytes. All our findings supported that AjMYC could regulate coelomocyte apoptosis by directly targeting AjBax expression in A. japonicus.

Preclinical Validation of Ubiquitin Receptor PSMD4 As Therapeutic Target in Multiple Myeloma

Background and Rationale Our preclinical studies have focused on Identification and validation of components within the ubiquitin proteasome system which can be targeted with novel therapies to overcome proteasome-inhibitor (PI)-resistance in multiple myeloma (MM). Our siRNA screening studies identified ubiquitin Receptor (UbR) PSMD4/Rpn10 as a mediator of MM cell growth and survival. Rpn10 is localized on the 19S regulatory lid of the proteasome, and plays a key role in chaperoning ubiquitinated substrate proteins for downstream 20S proteasomal degradation. Here, we show that inhibition of Rpn10 triggers potent anti-MM activity using both in in vitro and in vivo models of MM, including against PI-resistant MM cells. Materials and Methods Rpn10 knockout 293 cell line was generated using CRISPR/Cas9. Rpn10-inducible knockdown (KD) MM.1S cell line was generated using shRNA. Drug sensitivity, cell viability, and apoptosis assays were performed using WST/CellTiter-Glo assay, and Annexin V staining, respectively. Cell signaling and caspase activity were determined by western blotting. Proteasome activity was measured as previously described (Chauhan et al., Cancer Cell 2012, 22:345-358). A xenograft human MM model was used to characterize the role of Rpn10 on tumor progression. Statistical significance was assessed with Student's t test. Results 1) Analysis of MM patient gene expression profiling database showed that Rpn10 expression inversely correlates with overall survival (n=175; p= 0.00064). 2)Real-time PCR, immunoblotting, and immunohistochemistry of MM patient bone marrow showed higher Rpn10 levels in patient MM cells and MM cell lines versus normal cells. 3)Transient transfection of MM cells with Rpn10-siRNA decreased their viability; conversely, transfection with Rpn10-WT specifically rescued cells from growth-inhibitory activity of Rpn10-siRNA. Immunoblot analysis confirmed significant knockdown of Rpn10 by Rpn10-siRNA versus scrambled (scr)-siRNA, and restoration of Rpn10 levels in cells transfected with Rpn10-WT versus Rpn10-siRNA. 4)Genetic blockade of Rpn10 decreased viability in bortezomib-resistant MM cells. 5)CRISPR/Cas9-mediated knockout (KO) of Rpn10 decreased cell growth. 5)Both Rpn10-KO and inducible Rpn10-KD cells showed elevated levels of polyubiquitylated proteins. 6)Inhibition of Rpn10 induced apoptosis, cell-cycle arrest, activation of caspases, and endoplasmic reticulum stress response signaling. 7)Reduced tumor growth was noted in mice xenografted with Rpn10-KD MM.1S cells versus mice engrafted with WT-MM.1S cells. Conclusion Our data demonstrate the therapeutic potential of targeting ubiquitin receptor Rpn10/PSMD4, and provide the preclinical basis for development of Rpn10 inhibitors to overcome PI-resistance in MM. Disclosures Chauhan: C4 Therapeutics.: Equity Ownership; Stemline Therapeutics: Consultancy. Anderson:Sanofi-Aventis: Other: Advisory Board; Takeda: Consultancy, Speakers Bureau; Celgene: Consultancy, Speakers Bureau; Bristol-Myers Squibb: Other: Scientific Founder; Oncopep: Other: Scientific Founder; Amgen: Consultancy, Speakers Bureau; Janssen: Consultancy, Speakers Bureau.

A high yielding IFNAR1 ECD mammalian expression process for use in autoimmune disease drug development

Interferon-alpha receptor 1 (IFNAR1) is a target of interest for recombinant biotherapeutics that block the JAK/STAT pathway. This pathway is believed to play a role in many diseases including Hepatitis B and C, Herpes Simplex, Multiple Sclerosis, and other autoimmune disorders. By using IFNAR1 as a target to block Type I IFN from binding to the JAK/STAT pathway and prevent activation of this target, autoimmune disease progression can be modulated. Current IFNAR1 extracellular domain (ECD) expression and purification protocols are labor intensive with low product yield and limited scalability. In this work, we evaluate three different expression systems (baculovirus, human embryonic kidney 293 (HEK293×), and Chinese hamster ovary (CHO)) to improve expression of IFNAR1 ECD. We demonstrate the benefits of utilizing mammalian CHO cell transient transfection to increase expression titer, as well as an improved two-step purification process performed using immobilized metal affinity chromatography (IMAC) as the capture step and Ceramic Hydroxyapatite (CHT) Type II for HMW impurity removal in flow through mode. This process showed an 20-fold increase in productivity compared to the baseline process as measured by grams purified per liter of cell culture fluid. Lastly, the improved process showed good scalability, enabling efficient purification of 3.6 g of product from a 30 L scale bioreactor.

Cocaine- and amphetamine-regulated transcript promoter regulated by nicotine in nerve growth factor-treated PC12 cells.

Nicotine and cocaine- and amphetamine-regulated transcripts (CART) have several overlapping functions, such as the regulation of reward, feeding behavior, stress response, and anxiety. Previous studies showed that nicotine regulates CART expression in various brain regions. However, the molecular mechanisms underlying this regulation are not known. This study investigated the regulatory effect of nicotine on promoter activity of the CART gene in PC12 cells, which were differentiated into a neuronal phenotype by nerve growth factor (NGF) treatment. Two vectors containing reporter genes (Gaussia luciferase or mCherry) and the 1,140-bp upstream of the transcriptional start site of the mouse CART gene are used to analyze the CART promoter activity. Transient transfection of PC12 cells with either vector displayed strong promoter activity in both undifferentiated and differentiated PC12 cells. CART promoter activity in the PC12 cell line is increased by forskolin or NGF treatment. In differentiated PC12 cells, exposure to 50nM nicotine for 6h increased CART promoter activity. However, treatment with higher nicotine doses for 6h and treatment with all nicotine doses for 24h showed no effect. A nicotine concentration of 50nM is comparable to brain nicotine levels experienced by chronic smokers over long periods of time. Taken together, these data indicate that nicotine may exert some of its actions through the regulation of CART transcription in the brain.

LncRNA PLAC 2 downregulated miR-21 in non-small cell lung cancer and predicted survival

BackgroundLncRNA PLAC2 has been characterized as a tumor suppressive lncRNA in glioma. We investigated the role of PLAC2 in non-small cell lung cancer (NSCLC).MethodsA total of 187 NSCLC patients were admitted by The First Hospital of Jilin University from December 2010 to December 2014. All the patients were diagnosed by histopathological approaches. Transient cell transfections, RT-qPCR, invasion, and migration ability measurement, were applied for the experiments.ResultsPLAC2 was down-regulated, while miR-21 was up-regulated in NSCLC tissues compared to non-cancer tissues. Low PLAC2 levels in NSCLC tissues were associated with poor survival of NSCLC patients. PLAC2 and miR-21 were inversely correlated, and PLAC 2 over-expression in NSCLC cells resulted in the down-regulation of miR-21. However, miR-21 over-expression did not significantly affect PLAC2 expression. In addition, PLAC2 over-expression resulted in decreased migration and invasion rates of NSCLC cells. MiR-21 over-expression played the opposite role and attenuated the effects of PLAC2 over-expression.ConclusionsIn conclusion, lncRNA PLAC2 down-regulated miR-21 in NSCLC and inhibited cancer cell migration and invasion.

High cell density transient transfection of CHO cells for TGF-β1 expression.

High cell densities for transient transfection with polyethyleneimine (PEI) can be used for rapid and maximal production of recombinant proteins. High cell densities can be obtained by different cultivation systems, such as batch or perfusion systems. Herein, densities up to 18 million cells/mL were obtained by centrifugation for transfection evaluation. PEI transfection efficiency was easily determined by transfected enhanced green fluorescence protein (EGFP) reporter plasmid DNA (pDNA). A linear correlation between fluorescence intensity and transfection efficiency was improved. The transfection efficiency of PEI was highly dependent on the transfection conditions and directly related to the level of recombinant protein. Several factors were required to optimize the transient transfection process; these factors included the media type (which is compatible with low or high cell density transfection), the preculture CHO-K1 suspension cell density, and the pDNA to PEI level. Based on design of experiment (DoE) analyses, the optimal transfection conditions for 10×106cells/mL in the CHOMACS CD medium achieved 73% transfection efficiency and a cell viability of over 80%. These results were confirmed for the production of transforming growth factor-beta 1 (TGF-β1) in a shake flask. The purified TGF-β1 protein concentration from 60mL supernatant was 27µg/mL, and the protein was biologically active.

TGF-β1 mediates lncRNA GAPLINC expression to promote the migration and invasion of non-small cell lung cancer.

Purpose: The present study aims to investigate the involvement of lncRNA GAPLINC in non-small lung cancer (NSCLC).Patients and methods: The study included 70 patients with NSCLC (39 males and 31 females, 33 to 68 years, 49.3 ± 6.4 years). RT-qPCR, transient cell transfections, measurement of in vitro cell migration and invasion abilities and western blot were carrying out during the research.Results: We showed that GAPLINC was up-regulated in NSCLC tissues and positively correlated with TGF-β1. In vitro cell experiment showed that over-expression of TGF-β1 significantly up-regulated the expression of GAPLINC, while over-expression of GAPLINC failed to affect TGF-β1. Follow-up study showed that high GAPLINC level in NSCLC tissue was closely correlated with poor survival rate of NSCLC patients. Over-expressions of TGF-β1 and GAPLINC resulted to accelerated migration and invasion of NSCLC cells. In addition, the silencing of GAPLINC siRNA attenuated the effect of TGF-β1 treatment.Conclusion: TGF-β1 may mediate lncRNA GAPLINC expression to promote NSCLC cell invasion and migration.

Retroviral vector production by transient transfection of 293VEC-GALV cells

Background & Aim Introduction Retroviral vectors can permanently integrate their genetic material into chromosomes in the target cells for long-term, stable expression of the introduced genetic elements. It has been widely used since the 1980s and is the second most commonly employed system for gene transfer. Traditionally, retroviral vector production involves the preparation and characterization of a stable producer cell line from which the vector is produced as supernatant. It usually takes about 12 to 20 months from generation the stable producer cell line clone to the final release of the retroviral vector for clinical use. Due to the recent rapid growth of CAR-T cell therapies, a faster, more efficient method for retroviral vector production is required. We have, therefore, employed a novel manufacturing system using transient transfection for rapid GMP preparation of retroviral vectors. Methods, Results & Conclusion Methods Clinical retroviral vectors are produced from a master cell bank of 293Vec-Galv (BioVec Pharma, Quebec, Canada), a human embryonic kidney HEK293-based packaging cell line that stably expresses the Moloney Murine Leukemia gag-pol and Gibbon Ape Leukemia Virus envelope viral proteins. The cells are transfected with plasmid DNA that carries the gene(s) of interest (purified plasmid DNAs are produced by Puresyn Inc. Malvern PA, USA or Aldevron Inc. Fargo ND, USA). The transfection is carried out at 37°C and is mediated by PEIpro®-HQ (Polyplus Transfection, Illkirch, France), which is a highly qualified grade of polyethylenimine developed for large-scale bioproduction processes. About 24 hours post-transfection the medium is replaced by fresh complete medium. Supernatant containing the retrovirus is harvested at 48, 72 and 96 hours post-transfection and filtered through 0.45µm filter. The filtered supernatant is aliquoted, snap frozen and immediately transferred to storage in -80°C freezers. Results and Conclusion Eight retroviral vectors have been manufactured using this novel system at the CAGT GMP Vector Production Facility. Vector production from a single master cell bank of 293Vec-Galv takes about 4 weeks. Four vectors have been released for clinical trials. The transduction rate, phenotype and cytotoxic effect of T cells transduced by vectors produced by this novel system met release requirements, including absence of replication-competent retrovirus. Retroviral vector production by transient transfection of 293Vec-Galv cells saves time, is cost-efficient and safe ( Table 1 ).

Optimizing the production and affinity purification of HIV-1 envelope glycoprotein SOSIP trimers from transiently transfected CHO cells.

We describe methods to improve the efficiency with which HIV-1 Envelope glycoprotein SOSIP trimer immunogens can be produced by transient transfection of ExpiCHO-S cells and then affinity purified using the trimer-specific human monoclonal antibody PGT145. The specificity of PGT145 for properly folded trimers allows for the facile, one-step, isolation of these immunogens in research laboratories. PGT145 columns are also valuable as a component of more complex purification processes in current Good Manufacturing Practice programs. However, we found that PGT145 purification was highly variable and markedly inefficient when used to process supernatants from transiently transfected ExpiCHO-S cells expressing the BG505 SOSIP.664 and other trimeric Env proteins. In contrast, no such problems arose when the same Env proteins derived from a stable CHO cell line were processed on the same PGT145 columns, or with transient transfection supernatants from 293F cells. An investigation of the ExpiCHO-S transfection system identified the presence of polyanions, including but perhaps not limited to dextran sulfate, in the Enhancer component of the transfection system. We hypothesized that these polyanions bound to the cationic PGT145 epitope on the trimers and impeded their ability to bind to the PGT145 affinity column. We found that replacing the Enhancer component with alternative culture medium supplements substantially increased the yield of PGT145-purifiable trimers, and we also confirmed that both dextran sulfate and the Enhancer component were indeed inhibitors of PGT145 binding to BG505 SOSIP.664 trimers in immunoassays. The presence of polyanions, including but not limited to nucleic acids, should be considered in other circumstances where PGT145 columns are less efficient than expected at purifying native-like trimers.