Enhancement of cytotoxicities of ricin and Pseudomonas toxin in Chinese hamster ovary cells by nigericin

1981 ◽  
Vol 1 (6) ◽  
pp. 552-559
Author(s):  
B Ray ◽  
H C Wu
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Protein Synthesis ◽  
Cell Line ◽  
Chinese Hamster Ovary ◽  
Cho Cells ◽  
Diphtheria Toxin ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Ovary Cells ◽  
Pseudomonas Aeruginosa Exotoxin

Nigericin and monensin, ionophores for Na+ and K+, have been found to enhance the cytotoxicities of abrin, ricin, and Pseudomonas aeruginosa exotoxin A in Chinese hamster ovary (CHO) cells. They do not affect the cytotoxicity of diphtheria toxin in the same cell line. Maximal sensitization of the CHO cells toward ricin and Pseudomonas toxin requires preculture of CHO cells in the presence of nigericin. Inhibition of protein synthesis in CHO cells by ricin or Pseudomonas toxin is also enhanced by preculture of CHO cells in the presence of nigericin. These results suggest a common step in the intoxication process of ricin and Pseudomonas toxin, the rate of which is facilitated by pretreatment with nigericin. This step is, however, not shared by the intoxication of CHO cells with diphtheria toxin.

scholarly journals Enhancement of cytotoxicities of ricin and Pseudomonas toxin in Chinese hamster ovary cells by nigericin.

1981 ◽  
Vol 1 (6) ◽  
pp. 552-559 ◽  
Author(s):  
B Ray ◽  
H C Wu
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Protein Synthesis ◽  
Cell Line ◽  
Chinese Hamster Ovary ◽  
Cho Cells ◽  
Diphtheria Toxin ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Ovary Cells ◽  
Pseudomonas Aeruginosa Exotoxin

Nigericin and monensin, ionophores for Na+ and K+, have been found to enhance the cytotoxicities of abrin, ricin, and Pseudomonas aeruginosa exotoxin A in Chinese hamster ovary (CHO) cells. They do not affect the cytotoxicity of diphtheria toxin in the same cell line. Maximal sensitization of the CHO cells toward ricin and Pseudomonas toxin requires preculture of CHO cells in the presence of nigericin. Inhibition of protein synthesis in CHO cells by ricin or Pseudomonas toxin is also enhanced by preculture of CHO cells in the presence of nigericin. These results suggest a common step in the intoxication process of ricin and Pseudomonas toxin, the rate of which is facilitated by pretreatment with nigericin. This step is, however, not shared by the intoxication of CHO cells with diphtheria toxin.

scholarly journals Enhancement of ricin cytotoxicity in Chinese hamster ovary cells by depletion of intracellular K+: evidence for an Na+/H+ exchange system in Chinese hamster ovary cells.

1985 ◽  
Vol 101 (2) ◽  
pp. 350-357 ◽  
Author(s):  
P C Ghosh ◽  
R B Wellner ◽  
E J Cragoe ◽  
H C Wu
Keyword(s):  
Chinese Hamster Ovary ◽  
Cho Cells ◽  
Diphtheria Toxin ◽  
Chinese Hamster Ovary Cells ◽  
Human Fibroblasts ◽  
Chinese Hamster ◽  
Coated Pits ◽  
Ovary Cells ◽  
Pseudomonas Exotoxin A ◽  
K Depletion

Depletion of intracellular K+ has been reported to result in an arrest of the formation of coated pits in human fibroblasts (Larkin, J.M., M.S. Brown, J.L. Goldstein, and R.G.W. Anderson, 1983, Cell, 33:273-285). We have studied the effects of K+ depletion on the cytotoxicities of ricin, Pseudomonas exotoxin A, and diphtheria toxin in Chinese hamster ovary (CHO) cells. The cytotoxicities of ricin and Pseudomonas toxin were enhanced in K+-depleted CHO cells whereas the cytotoxicity of diphtheria toxin was reduced by K+ depletion. The effects of NH4Cl on the cytotoxicities of ricin, Pseudomonas toxin, and diphtheria toxin were found to be similar to those of K+ depletion, and there were no additive or synergistic effects on ricin cytotoxicity by NH4Cl in K+-depleted medium. The enhancement of ricin cytotoxicity by K+ depletion could be completely reversed by the addition of K+, Rb+, and partially by the addition of Cs+, before the ricin treatment, whereas Li+ was ineffective. These protective effects of K+ or Rb+ requires a functional Na+/K+ ATPase. CHO cells grown in K+-depleted media were found to contain 6.3-fold increase in intracellular Na+ level, concomitant with a 10-fold reduction in intracellular K+ level. The enhanced cytotoxicity of ricin in K+-free medium and the increased uptake of Na+ could be abolished by amiloride or amiloride analogues, which are known to be potent inhibitors of the Na+/H+ antiport system. Our results suggest that a depletion of intracellular K+ results in an influx of Na+, which is accompanied by the extrusion of H+. Consequently, there is an alkalinization of the cytosol and the ricin-containing endosomes. As a result, ricin is more efficiently released from the endosomes in-K+-depleted cells. Results from the studies of the binding, internalization, and degradation of 125I-ricin, and the kinetics of inhibition of protein synthesis by ricin in K+-depleted cells are consistent with this working hypothesis.

Review of the current methods of Chinese Hamster Ovary (CHO) cells cultivation for production of therapeutic protein

2020 ◽  
Vol 17 ◽  
Author(s):  
Shazid Md. Sharker ◽  
Md. Atiqur Rahman
Keyword(s):  
Chinese Hamster Ovary ◽  
Cho Cells ◽  
Mass Production ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Therapeutic Protein ◽  
Specific Productivity ◽  
Ovary Cells ◽  
Further Development ◽  
Interesting Area

Most of clinical approved protein-based drugs or under in clinical trial have a profound impact in the treatment of critical diseases. The mammalian eukaryotic cells culture approaches, particularly the CHO (Chinese Hamster Ovary) cells are mainly used in the biopharmaceutical industry for the mass-production of therapeutic protein. Recent advances in CHO cell bioprocessing to yield recombinant proteins and monoclonal antibodies have enabled the expression of quality protein. The developments of cell lines are possible to upgrade specific productivity. As a result, it holds an interesting area for academic as well as industrial researchers around the world. This review will concentrate on the recent progress of the mammalian CHO cells culture technology and the future scope of further development for the mass-production of protein therapeutics.

scholarly journals Cloning and characterization of small circular DNA from Chinese hamster ovary cells.

1984 ◽  
Vol 4 (1) ◽  
pp. 173-180 ◽  
Author(s):  
S W Stanfield ◽  
D R Helinski
Keyword(s):  
Chinese Hamster Ovary ◽  
Cho Cells ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Single Copy ◽  
Chromosomal Dna ◽  
Cho Cell ◽  
Ovary Cells ◽  
Chromosomal Sequences

Small polydisperse circular (spc) DNA was isolated and cloned, using BglII from Chinese hamster ovary (CHO) cells. The properties of 47 clones containing at least 43 different BglII fragments are reported. The majority of the clones probably contain entire sequences from individual spcDNA molecules. Most of the clones were homologous to sequences in CHO cell chromosomal DNA, and many were also homologous to mouse LMTK- cell chromosomal sequences. The majority of homologous CHO cell chromosomal sequences were repetitive, although a few may be single copy. Only a small fraction of cloned spcDNA molecules were present in every cell; most occurred less frequently than once in 15 cells. Localization studies indicated that at least a portion of spcDNA is associated with the nucleus in CHO cells.

scholarly journals Continued initiation of DNA synthesis in arginine-deprived Chinese hamster ovary cells.

1977 ◽  
Vol 73 (1) ◽  
pp. 200-205 ◽  
Author(s):  
A S Weissfeld ◽  
H Rouse
Keyword(s):  
Cell Cycle ◽  
Dna Synthesis ◽  
Chinese Hamster Ovary ◽  
Cho Cells ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Cell Multiplication ◽  
Ovary Cells ◽  
Cell Cycle Phases

When exponentially growing CHO cells were deprived of arginine (Arg), cell multiplication ceased after 12 h, but initiation of DNA synthesis continued: after 48 h of starvation with continuous [3H]thymidine exposure, 85% of the population had incorporated label, as detected autoradiographically. Consideration of the distribution of exponential cells in the various cell cycle phases leads to a calculation that most cells in G1 at the time that Arg was removed, as well as those in S, engaged in some DNA synthesis during starvation. In contrast, isoleucine (Ile)-starved cells did not initiate DNA synthesis, as has been reported by others. Experiments with cells synchronized by mitotic selection confirmed this difference in Arg- and Ile- deprived behavior, but also showed that cells which underwent the mitosis leads to G1 transition during Arg starvation remained arrested in G1 (G0?). The results suggest that Arg-deprived cells continue to maintain some proliferative function(s) while Ile-deprived cells do not.

In vitro biosynthesis of diphthamide, studied with mutant Chinese hamster ovary cells resistant to diphtheria toxin

1984 ◽  
Vol 4 (4) ◽  
pp. 642-650
Author(s):  
T J Moehring ◽  
D E Danley ◽  
J M Moehring
Keyword(s):  
Chinese Hamster Ovary ◽  
Diphtheria Toxin ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Elongation Factor ◽  
Synthetase Activity ◽  
Post Translational Modification ◽  
Ovary Cells ◽  
Elongation Factor 2

Diphthamide, a unique amino acid, is a post-translational derivative of histidine that exists in protein synthesis elongation factor 2 at the site of diphtheria toxin-catalyzed ADP-ribosylation of elongation factor 2. We investigated steps in the biosynthesis of diphthamide with mutants of Chinese hamster ovary cells that were altered in different steps of this complex post-translational modification. Biochemical evidence indicates that this modification requires a minimum of three steps, two of which we accomplished in vitro. We identified a methyltransferase activity that transfers methyl groups from S-adenosyl methionine to an unmethylated form of diphthine (the deamidated form of diphthamide), and we tentatively identified an ATP-dependent synthetase activity involved in the biosynthesis of diphthamide from diphthine. Our results are in accord with the proposed structure of diphthamide (B. G. VanNess, et al., J. Biol. Chem. 255:10710-10716, 1980).

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