Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    ISSN: 1573-0778
    Keywords: antisense ; apoptosis ; cell cycle ; c-jun ; protein production
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Expression of c-jun gene induces apoptosis ofcells cultured in serum-free medium. It also promotescell-cycling in serum-containing medium, leading cellsto die by overgrowth. Previously, we established anapoptosis-suppressible, cell-cycle arrestable cellline, c-jun AS, by transfecting Friend murineerythroleukemia (F-MEL) cells with adexamethasone-inducible antisense c-jun gene.Induction of the antisense c-jun transcriptionwith dexamethasone suppressed c-jun expression.As a result, c-jun AS cells survived inserum-free medium containing dexamethasone for a longtime, while F-MEL cells died quickly in the presenceor absence of dexamethasone. In serum-containingmedium, the growth of c-jun AS cells was viablyblocked by inducing antisense c-juntranscription, and the cells survived at thenon-growth state avoiding overgrowth. In the presentstudy, protein productivity of c-jun AS cellswas examined in comparison with that of wild typeF-MEL cells. C-jun AS and F-MEL cells werefurther transfected with a vector for expressingalkaline phosphatase as a protein to be produced, andnamed c-jun AS-SEAP and F-MEL-SEAP cells,respectively. In the serum-free medium withdexamethasone, c-jun AS-SEAP cells produced theprotein for up to 6 days, while F-MEL-SEAP cellsstopped production on day 3 due to cell death causedby serum deprivation. In the serum-containing mediumwith dexamethasone, c-jun AS-SEAP cells wereviably arrested in the cell cycle, and cell death dueto overgrowth was avoided. As the result, they couldproduce the protein for up to 18 days, whileF-MEL-SEAP cells stopped production within 7 days dueto cell death caused by overgrowth.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1573-0778
    Keywords: Enhancement of protein production ; growth suppression ; cell differentiation ; mammalian cell culture ; mRNA stability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Suppression of proliferation of cells which contain stable or stabilized mRNA coded for a protein to be produced, a partial mimic of cell differentiation, was examined for enhancing protein production by cultured mammalian cells. Hybridoma 2E3 cells which were adapted to be interleukin-6 sensitively growth-suppressed accumulated the mRNA of IgG1 which is reported stable, and IgG1 production rate increased as a result when their growth was suppressed with interleukin-6. A myeloma cell line was similarly adapted; the obtained myeloma cells can be used as host cells for enhancing production of exogenous proteins by suppressing growth with interleukin-6. Temperature-sensitively growth-suppressible mutants of mouse mammary carcinoma FM3A were transfected with cDNA of IgM λ1 chain and cultured at nonpermissive temperature to enhance production of λ1. Addition of various growth-suppressive reagents to culture medium was studied for finding methods suitable for suppressing growth while maintaining high cell viability. Caffeine yielded the best results among these reagents. Deprivation of various growth-supporting components in culture medium was also tested; simultaneous deprivation of insulin and transferrin viably suppressed growth of hybridoma 2E3 cells, resulting in enhanced antibody productivity.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 0006-3592
    Keywords: c-jun ; cell cycle ; apoptosis ; antisense ; growth deprivation ; F-MEL ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: F-MEL cells were transfected with the c-jun antisense gene located downstream of a glucocorticoid-inducible MMTV promoter, and the obtained cells were named c-jun AS cells. When the c-jun AS cells were treated with dexamethasone (DEX) in DMEM supplemented with 10% serum, the growth of the cells was completely suppressed for a duration of 16 days with a high cell viability exceeding 86%. The c-jun expression in the c-jun AS cells was suppressed moderately in the absence of DEX and strongly in the presence of DEX. The c-jun AS cells grew well and reached a density of 106 cells/mL without supplementation of any serum components. Viability was greater than 80% after the cells had been cultured for 8 days in the absence of DEX. The c-jun AS cells stayed at a constant cell density and high viability above 80% for 8 days when they were cultured in the presence of DEX under serum deprivation. In contrast, the wild type F-MEL cells were unable to grow and died by apoptosis in 3 days under serum deprivation. Internucleosomal cleavage of DNA, a landmark of apoptosis, was clearly detectable. Thus the c-jun AS cell line that is resistant to apoptosis induced by serum deprivation and can reversibly and viably be growth-arrested was established. A dual-signal model was proposed to explain the experimental result, the interlinked regulation of apoptosis, and growth by c-jun.© 1998 John Wiley & Sons, Inc. Biotechnol Bioeng 58:65-72, 1998.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1573-0778
    Keywords: antibody productivity ; growth suppression ; hybridoma ; interleukin-6 ; specific productivity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Monoclonal antibody production by hybridoma cells at moderately slowed growth states would be favorable for commercial scale production since cells can devote their resources to performing the differentiated function, immunoglobulin production. We found that a purified recombinant human interleukin-6, which had been reported to support or stimulate proliferation of B cell hybridoma/plasmacytoma cells, suppressed growth of a hybridoma cell line in serum-free medium. In the presence of the interleukin, the growth-suppressed cells were viable for remarkably long periods in batch culture, and after removal of the interleukin from the culture medium, they started to proliferate at their normal growth rate. As the concentration of the interleukin increased in the culture, the growth rate decreased and the specific antibody productivity (antibody production rate per cell) increased to 5-fold of control at 10 U ml−1 (2 ng ml−1) of the interleukin.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...