• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2001년도 추계학술발표대회
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• pp.221-224
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• 2001

Effect of hyperosmotic pressure on growth of recombinant Chinese hamster 。 vary cells and Erythropoietin (EPO) production was investigated. Cells were cultivated in batch modes at various osmolalities. When the osmolality increased from 314 to 463mOsm/Kg, specific EPO productivity (qp) was increased up to 1.6-fold but cell growth was inhibited. EPO has a complex oligosaccharide structure that plays an important role in biological activity in vivo. To investigate the influence of hypoerosmotic pressure on the glycosylation, structural analysis of oligosaccharide was calTied out. Recombinant human EPO was produced by CHO cells grown under various osmotic pressure and purified from culture supernatants by heparin-sepharose affinity column and immunoaffinity column. N-linked oligosaccharides were released enzymatically and isolated by paper chromatography. The isolated oligosaccharides were labeled with fluorescent dye, 2-aminobenzamide and analyzed with MonoQ anion exchange chromatography and GlycosepN amide chromatography for the assignment of GU (glucose unit) value. Glycan analysis by HPLC showed that neutral (asialo) oligosaccharide was increased slightly with an increase in osmolality. In portion of sialylated glycan, total relative amount of mono- and di-sialyated glycan was increased but that of tri- and tetra-sialylated glycan decreased as osmolality was increased.

• Biomolecules & Therapeutics
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• 제4권4호
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• pp.330-333
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• 1996

Acute intravenous toxicities of rHu-EPO (recombinant human erythropoietin) were investigated in Sprague-Dawley rats. Seven days after administration of rHu-EPO, we examined the clinical signs, mortalities, body weight and etc. No clinical signs and mortalities of toxicity were observed in animals. Also, a significant change of body weights was not observed. These results suggest that LD$_{50}$ value was >25,000 unit/ kg in Sprague-Dawley rats and the acute intravenous toxicities of rHu-EPO were not significant.t.

• 한국독성학회:학술대회논문집
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• 한국독성학회 2001년도 International Symposium on Dietary and Medicinal Antimutgens and Anticarcinogens
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• pp.168-168
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• 2001

To investigate the safety and toxicity of a recombinant human erythropoietin, YHB216, we performed 4-week repeated dose toxicity test in 4-month-old Beagle dogs. We injected intravenously everyday for 28 days with dosages of 0, 500, 2,500 and 12,500 I.U/kg body weight. There were not observed clinical signs or motality in the animals treated with YHB216. There were no significant changes in body weight, feed, or water consumption.(omitted)

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2-2
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• pp.170.3-171
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• 2003

An efficient Erythropoietin (EPO)-expression system in mammalian cells is required for massive production for therapeutic use. Ammonium ion is a major problem in the production of valuable recombinant proteins in cultured animal cells. Therefore, it is of importance to devise a system by which a high productivity of human therapeutic recombinant protein can be maintained or enhanced under low ammonium concentration. To reduce the ammonium ion accumulated in EPO producing Chinese Hamster Ovary (CHO) ceels, IBE, we introduced the first two genes of the urea cycle, carbamoyl phosphate synthetase (CPSI) and arnithine transcarbamoylase (OTC), into IBE using a stable transfection method. (omitted)

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2005년도 생물공학의 동향(XVII)
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• pp.146-147
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• 2005

• 대한임상약리학회:학술대회논문집
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• 대한임상약리학회 1992년도 정기총회 및 추계학술대회
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• pp.43-43
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• 1992

• Biomolecules & Therapeutics
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• 제6권1호
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• pp.82-88
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• 1998

LBO0014, a new recombinant human erythropoietin, was at dose levels of 0, 120, 600, and 3,000 IU/kg/day administered intravenously to pregnant Sprague-Dawley rats during the organogenetic period. All dams were subjected to caesarean section on day 20 of pregnancy, Effects of test substance on dams and embryonic development of Fl fetuses were examined. No treatment-related changes in clinical signs, body weight, and food consumption were observed at all doses tested. At necropsy spleen enlargement was found at 3,000 lU/kg. There was an ulcrease in the spleen weight at 600 and 3,0007/kg. Developmental toxicity was evident as increased resorptions at 3,000 lU/kg. At 600 and 3,000 RJ/kg, retarded ossification of fetuses occurred at an incidence of 31.3% and 64.7%, respectively. In addition, there was a delay in ossification of sternebrae and sacrocaudal vertebrae at 600 and 3,000 lU/kg. A decrease in the number of metacarpi and metatarsi was also seen at 3,000 nJ/kg. The results show that the no observed adverse effect dose level (NOAEL) for material toxicity was over 3,000 IU/kg/day and the NOAEL for developmental toxicity was 120 IU/kg/day.

• Toxicological Research
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• 제14권3호
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• pp.415-425
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• 1998

A recombinant human erythropoietin (rHuEPO) was administered intravenously at dosage levels of 0, 100, 500, and 2500IU/kg/day for a period of 3 weeks. There were no observed clinical signs and deaths related to treatment in all groups tested. Decreases in body weight gain and food consumption were observed only in males of 2,5000IU/kg group after 2 weeks. In hematological parameters, erythrocyte content, hematocrit values and hemoglobin concentration were dose- dependently increased in rHuEPO treated groups. The ratio between kidney weight and whole body weight was significantly increased in females of 500 and 2,500IU/kg groups. The spleen weight was also increased in both sexes of 500 and 2,500IU/kg groups. However, the absolute weight change of other organs was not observed. In histopathological examinations, the renal tubular basophilia was observed only in males and females of 2,500IU/kg groups. From these results, it is concluded that the no-observed adverse effect level (NOAEL) of rHuEPO is 100 IU/kg in rats in the present study.

• Journal of Microbiology and Biotechnology
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• 제18권12호
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• pp.1945-1952
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• 2008

Sialylation, the attachment of sialic acid residues to a protein, can affect the biological activity and in vivo circulatory half-life of glycoproteins. Human ${\alpha}2$,3-sialyltransferase (${\alpha}2$,3-ST) and ${\beta}1$,4-galactosyltransferase (${\beta}1$,4-GT) are responsible for terminal sialylation and galactosylation, respectively. Enhanced sialylation of human erythropoietin (EPO) by the expression of ${\alpha}2$,3-ST and ${\beta}1$,4-GT was achieved using recombinant Chinese hamster ovary (CHO) cells (EC1). The sialic acid content and sialylation of N-glycans were evaluated by HPLC. When ${\alpha}2$,3-ST was expressed in CHO cells (EC1-ST2), the sialic acid content (moles of sialic acid/mole of EPO) increased from 6.7 to 7.5. In addition, the amount of trisialylated glycans increased from 17.3% to 26.1 %. When ${\alpha}2$,3-ST and ${\beta}1$,4-GT were coexpressed in CHO cells (EC1-GTST15), the degree of sialylation was greater than that in EC1-ST2 cells. In the case of EC1-GTST15 cells, the sialic acid content increased to 8.2 and the proportion of trisialylated glycans was markedly increased from 17.3% to 35.5%. Interestingly, the amount of asialoglycans decreased only in the case of GTST15 cells (21.4% to 14.2%). These results show that coexpression of ${\alpha}2$,3-ST and ${\beta}1$,4-GT is more effective than the expression of ${\alpha}2$,3-ST alone. Coexpression of ${\alpha}2$,3-ST and ${\beta}1$,4-GT did not affect CHO cell growth and metabolism or EPO production. Thus, coexpression of ${\alpha}2$,3-ST and ${\beta}1$,4-GT may be beneficial for producing therapeutic glycoproteins with enhanced sialylation in CHO cells.

• Toxicological Research
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• 제21권3호
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• pp.209-218
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• 2005

We investigated effects of recombinant human erythropoietin (rHuEPO) on profiles of mRNA transcripts in 6 male cynomolgus (M. fascicularis) monkey's spleen for 4 weeks. Six monkeys, composed of control and treatment group (Control : M1, M2, M3: Treatment : M4, M5, M6) were intravenously administered 3 times per week without or with a dose of rHuEPO 2730 IU/0.1 ml/kg. After 4 weeks rHuEPO treatment, spleen was removed for RNA isolation. Splenic gene expression was assessed using Affymetrix U133A 2.0 arrays containing 18,400 transcripts and variants, including 14,500 well-characterized human genes. Gene expression pattern was very different between individuals even in same treatment. In rHuEPO treated groups showed number of genes were up- or down-regulated (M4: 79: M5: 48; M6: 73 genes). Six genes (epidermal growth factor receptor, calgranulin A, estrogen receptor binding site associated antigen, matrix metalloproteinase 19, zinc finger and BTB domain containing 16, progestin and adipoQ receptor) were commonly expressed in rHuEPO treated group. The different individual response could be major considering factor in monkey experiment. Further study is needed to clarify the different individual response to rHuEPO in molecular level. This study will be valuable in the fundamental understanding and validation of molecular toxicology for bio-generic drugs including rHuEPO in cynomolgus monkey.