Publications by authors named "Yan-Long Jia"

Article Synopsis
  • Epigenetic regulation is crucial for controlling cellular processes like growth and cell death, and small molecule modulators can fine-tune gene expression in these processes.
  • The study found that the dual-HDAC/LSD1 inhibitor I-4 significantly boosted monoclonal antibody production in CHO cells, leading to nearly double the antibody titer despite causing cell cycle arrest.
  • Results indicate that I-4 enhances protein expression by increasing histone acetylation and downregulating the HDAC5 gene, demonstrating a new approach to improve recombinant protein yields.
View Article and Find Full Text PDF

Vascular endothelial growth factor receptors (VEGFRs) have emerged as the most promising anti-angiogenic therapeutic targets for the treatment of recurrent glioblastomas (GBM). However, anti-VEGF treatments led to the high proportion of non-responder patients or non lasting clinical response and the tumor progression to the greater malignant stage. To overcome these problems, there is an utmost need to develop innovative anti-angiogenic therapies.

View Article and Find Full Text PDF

Previous work has shown that the EF-1α promoter of episomal vectors maintains high-level transgene expression in stably transfected Chinese hamster ovary (CHO) cells. However, the transgene expression levels need to be further increased. Here, we first incorporated matrix attachment regions (MARs), ubiquitous chromatin opening element (UCOE), stabilizing anti repressor elements 40 (STAR 40) elements into episomal vector at different sites and orientations, and systemically assessed their effects on transgene expression in transfected CHO-K1 cells.

View Article and Find Full Text PDF
Article Synopsis
  • CHO cells can be genetically engineered to boost their ability to produce therapeutic proteins, with recent focus on cell cycle and autophagy regulation to improve yields.
  • The study explored the small-molecule compound apilimod, which positively impacts recombinant protein expression by blocking the cell cycle at the G0/G1 phase.
  • Apilimod treatment altered the expression of key cell cycle regulators and reduced lysosome biogenesis and autophagy, indicating its potential as an enhancer for protein production in CHO cells.
View Article and Find Full Text PDF
Article Synopsis
  • CHO cells are the main host for producing therapeutic proteins, but higher yields are needed to meet market demands and cut costs.
  • The study explored three SAR elements from the human genome, which were added to a eukaryotic vector and transfected into CHO cells to enhance protein expression.
  • Results indicated that SAR7 and SAR40 significantly boosted and sustained gene expression compared to controls, suggesting these elements could improve the efficiency of recombinant protein production in CHO cells.
View Article and Find Full Text PDF
Article Synopsis
  • The biopharmaceutical industry faces challenges in creating stable cell lines that produce high levels of recombinant proteins, making expression vector optimization important for increasing transgene expression stability.* -
  • The study analyzed various poly A elements in CHO cells, finding that SV40 and synthetic poly A significantly enhanced transgene expression and reduced variability over time.* -
  • Surprisingly, while higher levels of adalimumab were expressed with these elements, the results indicated that protein expression levels were not directly tied to gene copy number or mRNA levels.*
View Article and Find Full Text PDF
Article Synopsis
  • Most therapeutic recombinant proteins are produced in mammalian cell lines like CHO and HEK293F, but proteins from CHO may cause immune responses due to different glycan structures.
  • This study tested eight common promoters in HEK293F cells to find which one yields the highest expression of recombinant proteins, revealing that the CAG promoter combined with the CMV enhancer produced the best results.
  • Additionally, using mild hypothermia post-transfection further boosted the expression levels, confirming that the CAG promoter is highly effective in producing recombinant proteins in HEK293F cells.
View Article and Find Full Text PDF

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.

View Article and Find Full Text PDF

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 β-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.

View Article and Find Full Text PDF

Matrix attachment regions (MARs) are DNA fragments with specific motifs that enhance transgenic expression; however, the characteristics and functions of these elements remain unclear. In this study, we designed and synthesized three short chimeric MARs, namely, SM4, SM5, and SM6, with different numbers and orders of motifs on the basis of the features and motifs of previously reported MARs, namely, SM1, SM2, and SM3, respectively. Expression vectors with six synthetic MARs flanking the down or upstream of the expression cassette for enhanced green fluorescence protein (EGFP) were constructed and introduced into Chinese hamster ovary (CHO) cells.

View Article and Find Full Text PDF

Forests can improve climate and regulate micro-environment. The study of forest micro-climate is of great significance to reveal forest ecosystem function and evaluate the benefits of forest ecological environment. With broadleaved Korean pine forest in Changbai Mountain as test material, the diurnal and seasonal variations of the mean, maximum and minimum temperature, relative humidity and surface soil temperature were analyzed based on the meteorological data of flux tower in the forest and nearby meteorological station in the open land from 2003 to 2014.

View Article and Find Full Text PDF
Article Synopsis
  • The study aimed to examine how DNA topoisomerase I gene (TOP1) matrix attachment regions (MARs) influence transgene expression in Chinese hamster ovary (CHO) cells.
  • Results indicated that including TOP1 MARs at the ends of an enhanced green fluorescence protein (EGFP) gene significantly boosted both transient and stable expression levels, with specific configurations yielding the best outcomes.
  • The research suggests that using TOP1 MARs could enhance the production of recombinant proteins in mammalian cells, although transgene copy number did not impact expression uniformity in monoclonal CHO cells.
View Article and Find Full Text PDF
Article Synopsis
  • The authors requested the retraction of their paper.
  • The retraction indicates that the paper is no longer considered valid or credible.
  • Readers should disregard the findings and conclusions of the retracted paper.
View Article and Find Full Text PDF

CHO cells are the preferred host for the production of complex pharmaceutical proteins in the biopharmaceutical industry, and genome engineering of CHO cells would benefit product yield and stability. Here, we demonstrated the efficacy of a Dnmt3a-deficient CHO cell line created by CRISPR/Cas9 genome editing technology through gene disruptions in Dnmt3a, which encode the proteins involved in DNA methyltransferases. The transgenes, which were driven by the 2 commonly used CMV and EF1α promoters, were evaluated for their expression level and stability.

View Article and Find Full Text PDF
Article Synopsis
  • Chinese hamster ovary (CHO) cells are commonly used for producing recombinant proteins, but face challenges with unstable transgene expression and low copy numbers.
  • This study tested eleven internal ribosome entry site (IRES) elements to improve foreign gene expression in CHO-S cells by constructing plasmids with various IRES sequences linked to the enhanced green fluorescent protein (EGFP) gene.
  • The results revealed that the IRES from human rhinovirus (HRV) led to the highest levels of EGFP and erythropoietin (EPO) expression, indicating its effectiveness for enhancing stable expression in CHO-S cells.
View Article and Find Full Text PDF

Chinese hamster ovary (CHO) cells have become the most widely utilized mammalian cell line for the production of recombinant proteins. However, the product yield and transgene instability need to be further increased and solved. In this study, we investigated the effect of five different introns on transgene expression in CHO cells.

View Article and Find Full Text PDF

Chinese hamster ovary (CHO) cells are one of the most commonly used expression systems for the production of recombinant proteins but low levels of transgene expression and transgene silencing are frequently encountered. Epigenetic regulatory elements such as the chicken β-globin locus control region hypersensitive site 4 (HS4) and scaffold/matrix attachment regions (S/MARs) have positive effects on transgene expression. In this study, a chimeric HS4-SAR was cloned upstream or downstream of an enhanced green fluorescent protein (eGFP) expression cassette in a eukaryotic vector, and the resulting vectors were transfected into CHO cells.

View Article and Find Full Text PDF

In the present study, six commonly used promoters, including cytomegalovirus major immediate-early (CMV), the CMV enhancer fused to the chicken beta-actin promoter (CAG), human elongation factor-1α (HEF-1α), mouse cytomegalovirus (mouse CMV), Chinese hamster elongation factor-1α (CHEF-1α), and phosphoglycerate kinase (PGK), a CMV promoter mutant and a CAG enhancer, were evaluated to determine their effects on transgene expression and stability in transfected CHO cells. The promoters and enhancer were cloned or synthesized, and mutation at C-404 in the CMV promoter was generated; then all elements were transfected into CHO cells. Stably transfected CHO cells were identified via screening under the selection pressure of G418.

View Article and Find Full Text PDF

A chimeric DNA fragment containing an interferon-beta matrix attachment region (MAR) and an immunoglobulin MAR (PSAR2) was synthesized. PSAR2 was cloned into the upstream or downstream region of an enhanced green fluorescent protein (eGFP) expression cassette in a eukaryotic vector, which was then transfected into CHO cells. The results showed that PSAR2 did not effectively increase transgene expression when it was cloned into the upstream region of the eGFP expression cassette.

View Article and Find Full Text PDF

Matrix attachment regions (MARs) are cis-acting DNA elements that can increase transgene expression levels in a CHO cell expression system. To investigate the effects of MAR combinations on transgene expression and the underlying regulatory mechanisms, we generated constructs in which the enhanced green fluorescent protein (eGFP) gene flanked by different combinations of human β-interferon and β-globin MAR (iMAR and gMAR, respectively), which was driven by the cytomegalovirus (CMV) or simian virus (SV) 40 promoter. These were transfected into CHO-K1 cells, which were screened with geneticin; eGFP expression was detected by flow cytometry.

View Article and Find Full Text PDF

Background: Gene therapy in mammalian cells requires vectors exhibiting long-term stability and high expression. Episomal gene expression vectors offer a safe and attractive alternative to those that integrate into the host cell genome.

Materials & Methods: In the present study, we developed a new episomal vector based on the insulator, chicken hypersensitive site 4 (cHS4).

View Article and Find Full Text PDF

The characteristic sequence of β-interferon matrix attachment regions (MARs) can mediate transgene expression via episomal vectors in Chinese hamster ovary (CHO) cells. However, the host cells were from hamster ovaries, which are not suitable target cells for gene therapy. In this study, we aimed to evaluate the suitability of 12 different human cell lines as target cells for gene therapy.

View Article and Find Full Text PDF

Romidepsin (FK228) is one of the most promising histone-deacetylase inhibitors due to its potent antitumor activity, and has been used as a practical option for cancer therapy. However, FK228-induced changes in protein modifications and the crosstalk between different modifications has not been reported. To better understand the underlying mechanisms of FK228-related cancer therapy, we investigated the acetylome, phosphorylation, and crosstalk between modification datasets in colon cancer cells treated with FK228 by using stable-isotope labeling with amino acids in cell culture and affinity enrichment, followed by high-resolution liquid chromatography tandem mass spectrometry analysis.

View Article and Find Full Text PDF
Article Synopsis
  • - Dunaliella salina, a salt-tolerant marine alga, serves as a crucial model for understanding how extremophiles survive and their practical uses.
  • - The study utilized 2D-DIGE and MALDI-TOF/TOF MS to analyze protein expression under different salt concentrations, identifying 141 protein spots with significant changes.
  • - Key proteins linked to stress responses, photosynthesis, respiration, and amino acid synthesis were identified, indicating their roles in managing salt stress and maintaining cellular functions.
View Article and Find Full Text PDF