scholarly journals Dissociation of centrosome replication events from cycles of DNA synthesis and mitotic division in hydroxyurea-arrested Chinese hamster ovary cells.

1995 ◽  
Vol 130 (1) ◽  
pp. 105-115 ◽  
Author(s):  
R Balczon ◽  
L Bao ◽  
W E Zimmer ◽  
K Brown ◽  
R P Zinkowski ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Synthesis ◽  
Cho Cells ◽  
Molecular Mechanisms ◽  
Chinese Hamster Ovary Cells ◽  
Somatic Cells ◽  
Chinese Hamster ◽  
Mitotic Division ◽  
Northern Blotting ◽  
Dialyzed Serum

Relatively little is known about the mechanisms used by somatic cells to regulate the replication of the centrosome complex. Centrosome doubling was studied in CHO cells by electron microscopy and immunofluorescence microscopy using human autoimmune anticentrosome antiserum, and by Northern blotting using the cDNA encoding portion of the centrosome autoantigen pericentriolar material (PCM)-1. Centrosome doubling could be dissociated from cycles of DNA synthesis and mitotic division by arresting cells at the G1/S boundary of the cell cycle using either hydroxyurea or aphidicolin. Immunofluorescence micros-copy using SPJ human autoimmune anticentrosome antiserum demonstrated that arrested cells were able to undergo numerous rounds of centrosome replication in the absence of cycles of DNA synthesis and mitosis. Northern blot analysis demonstrated that the synthesis and degradation of the mRNA encoding PCM-1 occurred in a cell cycle-dependent fashion in CHO cells with peak levels of PCM-1 mRNA being present in G1 and S phase cells before mRNA amounts dropped to undetectable levels in G2 and M phases. Conversely, cells arrested at the G1/S boundary of the cell cycle maintained PCM-1 mRNA at artificially elevated levels, providing a possible molecular mechanism for explaining the multiple rounds of centrosome replication that occurred in CHO cells during prolonged hydroxyurea-induced arrest. The capacity to replicate centrosomes could be abolished in hydroxyurea-arrested CHO cells by culturing the cells in dialyzed serum. However, the ability to replicate centrosomes and to synthesize PCM-1 mRNA could be re-initiated by adding EGF to the dialyzed serum. This experimental system should be useful for investigating the positive and negative molecular mechanisms used by somatic cells to regulate the replication of centrosomes and for studying and the methods used by somatic cells for coordinating centrosome duplication with other cell cycle progression events.

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.

scholarly journals Chinese hamster ovary cells replicate adenovirus deoxyribonucleic acid.

1981 ◽  
Vol 1 (3) ◽  
pp. 208-215 ◽  
Author(s):  
M Longiaru ◽  
M S Horwitz
Keyword(s):  
Dna Synthesis ◽  
Chinese Hamster Ovary ◽  
Cho Cells ◽  
Deoxyribonucleic Acid ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Adenovirus Type ◽  
Viral Dna ◽  
Nuclear Extracts

Chinese hamster ovary (CHO) cells infected with adenovirus type 2 (Ad2) produced amounts of viral deoxyribonucleic acid (DNA) equal to that synthesized in permissively infected HeLa cells. However, there was 6,000-fold less virion produced in CHO cells. Since the structural viral polypeptides were not detected by pulse-labeling CHO cells at various times postinfection, the block in virion formation is located between the synthesis of viral DNA and late proteins. Extracts of CHO cells could also function in a recently reported in vitro Ad2 DNA synthesis system which is dependent upon the addition of exogenous Ad2 DNA covalently linked to a 5'-terminal protein (Ikeda et al., Proc. Natl. Acad. Sci. U.S.A. 77:5827-5831, 1980). Extracts of infected CHO cytoplasm were able to complement uninfected CHO nuclear extracts to synthesize viral DNA on Ad2 templates. This in vitro replication system has the potential to probe host DNA synthesis requirements as well as viral factors.

scholarly journals CHANGES IN SURFACE MORPHOLOGY OF CHINESE HAMSTER OVARY CELLS DURING THE CELL CYCLE

1973 ◽  
Vol 57 (3) ◽  
pp. 815-836 ◽  
Author(s):  
Keith Porter ◽  
David Prescott ◽  
Jearl Frye
Keyword(s):  
Cell Cycle ◽  
Chinese Hamster Ovary ◽  
Cho Cells ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Ovary Cells ◽  
Confluent Culture ◽  
Large Numbers ◽  
Wide Range ◽  
Surface Changes

Synchronized populations of Chinese hamster ovary (CHO) cells in confluent culture have been examined by scanning electron microscopy and their surface changes noted as the cells progress through the cycle. During G1 it is characteristic for cells to show large numbers of microvilli, blebs, and ruffles. Except for the ruffles, these tend to diminish in prominence during S and the cells become relatively smooth as they spread thinly over the substrate. During G2 microvilli increase in number and the cells thicken in anticipation of rounding up for mitosis. It appears that the changes observed here reflect the changing capacity of CHO cells during the cycle to respond to contact with other cells in the population, because, as noted in the succeeding paper (Rubin and Everhart), CHO cells in sparse nonconfluent cultures do not show the same wide range of changes during the cell cycle. Normal, nontransformed cells of equivalent type in confluent culture are essentially devoid of microvilli, blebs, and ruffles. The relation of these surface configurations to the internal structure of the cell is discussed.

SPRR1B overexpression enhances entry of cells into the G0 phase of the cell cycle

2003 ◽  
Vol 285 (4) ◽  
pp. L889-L898 ◽  
Author(s):  
Yohannes Tesfaigzi ◽  
Paul S. Wright ◽  
Steven A. Belinsky
Keyword(s):  
Cell Cycle ◽  
Cell Lines ◽  
Cho Cells ◽  
Chinese Hamster ◽  
Human Tumor ◽  
Northern Blotting ◽  
G0 Phase ◽  
In Situ Hybridizations ◽  
Respiratory Epithelial ◽  
Lung Adenocarcinomas

Many studies have established the role of SPRR1B during squamous differentiation of skin and respiratory epithelial cells. However, its role in nonsquamous cells is largely unknown. We reported that expression of SPRR1B in Chinese hamster ovary (CHO) cells is increased as they enter the G0 phase of the cell cycle. The purpose of this study was to further investigate the SPRR1B expression pattern in nonsquamous tumors and to study its role in these cells. Expression of SPRR1B was detected by Northern blotting in a higher percentage of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone-induced compared with beryllium metal-induced rat lung adenocarcinomas. In situ hybridizations confirmed that SPRR1B is expressed in individual or clusters of cells of nonsquamous cells from mouse, rat, and human adenocarcinomas. The same pattern of expression was observed in adenocarcinomas formed in nude mice from cell lines established from adenocarcinomas. SPRR1B expression was downregulated in the cell lines derived from adenocarcinoma when cells were enriched in G0 at low confluence. Tetraploidy was induced in CHO, mouse, and human tumor cell lines by stably overexpressing SPRR1B, whereas control cells showed no change in ploidy. Inducible expression of this protein for shorter periods using the ecdyson system did not affect growth rate or the ploidy of CHO cells but accelerated entry into G0/G1 compared with controls. These findings indicate that SPRR1B is likely coupled primarily to signals responsible for withdrawal from the proliferative state rather than the final stages of cellular quiescence and that its overexpression for prolonged periods may disrupt the normal progression of mitosis.

scholarly journals Effects of turmeric and its active principle, curcumin, on bleomycin-induced chromosome aberrations in Chinese hamster ovary cells

1999 ◽  
Vol 22 (3) ◽  
pp. 407-413 ◽  
Author(s):  
Maria Cristina P. Araújo ◽  
Francisca da Luz Dias ◽  
Sergio N. Kronka ◽  
Catarina S. Takahashi
Keyword(s):  
Cell Cycle ◽  
Chinese Hamster Ovary ◽  
Cho Cells ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Active Principle ◽  
Chromosomal Damage ◽  
Ovary Cells ◽  
Naturally Occurring ◽  
Plant Constituents

Naturally occurring antioxidants have been extensively studied for their capacity to protect organisms and cells from oxidative damage. Many plant constituents including turmeric and curcumin appear to be potent antimutagens and antioxidants. The effects of turmeric and curcumin on chromosomal aberration frequencies induced by the radiomimetic agent bleomycin (BLM) were investigated in Chinese hamster ovary (CHO) cells. Three concentrations of each drug, turmeric (100, 250 and 500 <FONT FACE="Symbol">m</FONT>g/ml) and curcumin (2.5, 5 and 10 <FONT FACE="Symbol">m</FONT>g/ml), were combined with BLM (10 <FONT FACE="Symbol">m</FONT>g/ml) in CHO cells treated during the G1/S, S or G2/S phases of the cell cycle. Neither turmeric nor curcumin prevented BLM-induced chromosomal damage in any phases of the cell cycle. Conversely, a potentiation of the clastogenicity of BLM by curcumin was clearly observed in cells treated during the S and G2/S phases. Curcumin was also clastogenic by itself at 10 µg/ml in two protocols used. However, the exact mechanism by which curcumin produced clastogenic and potentiating effects remains unknown.

scholarly journals Effect of taxol on chromosome aberrations induced by gamma radiation or by doxorubicin in Chinese hamster ovary cells

1997 ◽  
Vol 20 (3) ◽  
pp. 389-395 ◽  
Author(s):  
Francisca da Luz Dias ◽  
Lusânia M.G. Antunes ◽  
Catarina S. Takahashi
Keyword(s):  
Cell Cycle ◽  
Gamma Radiation ◽  
Chromosomal Aberrations ◽  
Chinese Hamster Ovary ◽  
Cho Cells ◽  
Chinese Hamster Ovary Cells ◽  
Combined Therapy ◽  
Chinese Hamster ◽  
Simultaneous Treatment ◽  
G2 Phase

Combined therapy with radiation and chemotherapy has being increasingly used in cancer treatment. The effect of combinations of taxol (0.08 mug/ml) with doxorubicin (DXR, 0.5 or 1.0 mug/ml) or gamma radiation (20 or 40 cGy) was examined in two different treatment schedules (pretreatment or simultaneous treatment) using Chinese hamster ovary (CHO) cells treated at the G2 phase of the cell cycle. The results showed that taxol did not have a radiosensitizing effect on the chromosomal aberrations induced by gamma radiation nor did it have a potentiating effect on the chromosomal aberrations induced by DXR in CHO cells treated in the G2 phase of the cell cycle

Chinese hamster ovary cells replicate adenovirus deoxyribonucleic acid

1981 ◽  
Vol 1 (3) ◽  
pp. 208-215
Author(s):  
M Longiaru ◽  
M S Horwitz
Keyword(s):  
Dna Synthesis ◽  
Chinese Hamster Ovary ◽  
Cho Cells ◽  
Deoxyribonucleic Acid ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Adenovirus Type ◽  
Viral Dna ◽  
Nuclear Extracts

Chinese hamster ovary (CHO) cells infected with adenovirus type 2 (Ad2) produced amounts of viral deoxyribonucleic acid (DNA) equal to that synthesized in permissively infected HeLa cells. However, there was 6,000-fold less virion produced in CHO cells. Since the structural viral polypeptides were not detected by pulse-labeling CHO cells at various times postinfection, the block in virion formation is located between the synthesis of viral DNA and late proteins. Extracts of CHO cells could also function in a recently reported in vitro Ad2 DNA synthesis system which is dependent upon the addition of exogenous Ad2 DNA covalently linked to a 5'-terminal protein (Ikeda et al., Proc. Natl. Acad. Sci. U.S.A. 77:5827-5831, 1980). Extracts of infected CHO cytoplasm were able to complement uninfected CHO nuclear extracts to synthesize viral DNA on Ad2 templates. This in vitro replication system has the potential to probe host DNA synthesis requirements as well as viral factors.

scholarly journals DNA replication in Chinese hamster ovary cells made permeable to nucleotides by tween-80 treatment.

1976 ◽  
Vol 69 (3) ◽  
pp. 732-736 ◽  
Author(s):  
D Billen ◽  
A C Olson
Keyword(s):  
Dna Replication ◽  
Dna Synthesis ◽  
Chinese Hamster Ovary ◽  
Cho Cells ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Tween 80 ◽  
S Phase ◽  
Ovary Cells ◽  
Permeabilized Cells

We have developed a method for permeabilizing CHO cells to nucleotides under conditions which allow most cells to remain viable. Permeabilized cells can carry out ATP-dependent, semiconservative synthesis of DNA. The data are consistent with the continuation of DNA synthesis in those cells in S phase at the time of treatment, possibly limited to completion of replicon synthesis without new initiations.

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.

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