Optimization of glycosylation type of recombinant human growth hormone-Fc fusion protein expressed in CHO cells / 中国生物制品学杂志

@#Objective To optimize the expression of recombinant human growth hormone-Fc(rhGH-Fc)fusion protein in CHO cells in order to obtain better glycosylation ratio and lower content of highmannose.Methods CHO cells expressing rhGH-Fc were cultured in a 7 L bioreactor.The glycosylation modifications of rhGH-Fc were adjusted by improving the composition of feeding media(using three commercial media:Gly-1:EX-CELL Glycosylation Adjust,Gly-2:SHEFF-CHO PLUS PG ACF and Gly-3:EfficientFeed C + AGT Supplement & GlycanTune C + Total Feed),and the glycosylation type and proportion of the target proteins were analyzed by mass spectrometry.Results The G0F(main glycosylation types:G0,G1 and G2;F:fucose)of Gly-1,Gly-2 and Gly-3 were 32.89%,58.66% and 33.28%,the G1F were 31.39%,18.03%and 34.90%,and the G2F were 31.39%,18.03% and 34.90%,respectively.Gly-1 and Gly-3 made the target protein contain less G0F while more G2F;Gly-3 feeding scheme-showed less high mannose modification than the other two schemes.Conclusion Gly-1 medium changed the glycosylation modification from G0F to G1F and G2F,while Gly-2 medium changed that from G2F and G1F to G0F.However,Gly-3 medium changed the glycosylation modification from G0F to G1F and G2F,and the contentof high mannose was less than 5%,which may have a better effect on modifying glycosylation type and proportion of the target protein.

Antiproliferative evaluation of tall-oil docosanol and tetracosanol over CHO-K1 and human melanoma cells

Background Polycosanols derived from plant species have traditionally been used in medicine as antiproliferative agents for treating various viruses (primarily the herpes simplex virus). However, few studies have studied their effects on hyperproliferative cell lines. In this work, the antiproliferative capacity of polycosanols from tall-oil pitch, obtained from black liquor soaps in the kraft pulping process of cellulose (specifically from Pinus radiata, Pinus taede, and Eucalyptus globulus), was evaluated on CHO-K1 and CRL-1974 human melanoma cell lines. Results The proliferative capacities and cell viabilities were measured for 72 and 140 h, respectively. Treatment with docosanol produced differential effects on the CHO-K1 and human melanoma cells and significantly affected their proliferation rates, but not their cell viabilities. Tetracosanol produced a significant negative effect on the proliferation of human melanoma cells, and this effect was less than that caused by docosanol. However, it had no effect on the proliferation of CHO-K1 cells and did not induce any significant effect on the viability of the studied cell lines. Conclusion Docosanol and tetracosanol induced antiproliferative effects on the studied cell lines and exhibited significantly greater effects on the oncogenic cell lines. Prior to this study, the capacity of these polycosanols has never been investigated. Future studies will be necessary to determine their mechanisms of action on these cell systems.

Determination of the antimutagenicity of an aqueous extract of Rhizophora mangle L. (Rhizophoraceae), using in vivo and in vitro test systems

An aqueous extract of Rhizophora mangle L. bark is used as raw material in pottery making in the State of Espirito Santo, Brazil. This extract presents large quantities of tannins, compounds possessing antioxidant properties. Tannin antioxidant activity, as a plant chemical defense mechanism in the process of stabilizing free radicals, has been an incentive to studies on anti-mutagenicity. The present work aimed to evaluate possible antimutagenic activity of a R. mangle aqueous extract, using the Allium cepa test-system and micronuclear (MN) assay with blockage of cytokinesis in Chinese hamster ovary cells (CHO-K1). The Allium cepa test-system indicated antimutagenic activity against the damage induced by the mutagenic agent methyl methanesulfonate. A reduction in both MN cell frequency and chromosome breaks occurred in both the pre and post-treatment protocols. The MN testing of CHO-K1 cells revealed anti-mutagenic activity of the R. mangle extract against methyl methanesulfonate and doxorubicin in pre, simultaneous and post-treatment protocols. These results suggest the presence of phyto-constituents in the extract presenting demutagenic and bio-antimutagenic activities. Since the chemical constitution of Rhizophora mangle species presents elevated tannin content, it is highly probable that these compounds are the antimutagenic promoters themselves.

Gabapentin Attenuates the Activation of Transient Receptor Potential A1 by Cinnamaldehyde

Gabapentin is used as an effective drug for relieving pain, but the main mechanism is still unclear. Recently, voltage-gated Ca2+ channel subunits are suggested for the main target for the analgesic action of gabapentin. We wonder whether gabapentin directly modulates other specific ion channels peripherally expressed in the sensory neurons. To test this, we used a heterologous expression system in which the cell lines transiently expressed thermosensitive transient receptor potential ion channels (thermoTRPs) as well as the primary cultured mouse trigeminal neurons. The application of gabapentin reduced the increases in the intracellular Ca2+ level caused by TRPA1 activation in the heterologous expression system whereas the responses via actions of other thermoTRPs were not dramatically affected by the gabapentin treatment. Gabapentin also attenuated the TRPA1-mediated intracellular Ca2+ increases in the cultured trigeminal neurons. These findings suggest TRPA1 in the peripheral sensory neurons as a novel target for the analgesic of gabapentin.

First genotoxicity study of Paraná river water from Argentina using cells from the clam Corbicula fluminea (Veneroida Corbiculidae) and Chinese hamster (Cricetulus griseus Rodentia, Cricetidae) K1 cells in the comet assay

High concentrations of xenobiotics from urban and industrial wastes have contributed to the contamination of many aquatic environments. We used the comet assay to evaluate the genotoxic potential of water collected from the River Paraná, which receives a great deal of waste, at three points (Puerto Piray, Eldorado and Montecarlo) in the Misiones Province of Argentina. The in vivo comet assay used 40 freshwater clams (Corbicula fluminea) while the in vitro comet assay used Chinese hamster (Cricetulus griseus) K1 cell (CHO-K1) cultures with the mutagen ethyl methanesulfonate (EMS) as the positive control and phosphate buffered saline (PBS) as the negative control. Both assays showed statistically significant differences between the three sampling sites in relation to the negative control, the results of this preliminary study indicating that at these three sites water from the Paraná River presents genotoxic potential.

Evaluating kinetic and physiological features of rCHO-K1 cells cultured on microcarriers for production of a recombinant metalloprotease/disintegrin

We present kinetic and physiological data regarding the culturing of rCHO-K1 cells on various microcarriers, to evaluate the potential of this culture strategy for mass production of these cells and expression of a recombinant disintegrin. Cultures were performed in 500 mL spinner flasks in DMEM culture medium with 10 percent v/v fetal calf serum, gently shaken at 37 C, pH 7.4, in a 10 percent v/v CO2 atmosphere. The following values were obtained, respectively, for the adhesion time-constant Ka (h) and specific growth rate micron max (d-1) on each microcarrier: Cytodex 1 (0.91, 0.45), Cultispher S (0.28, 0.34), Immobasil FS (0.85, 0.52) and Pronectin F (5.12, 0.67). Metabolic characteristics showed some variation among the cultures with the four microcarriers, the most significant being the higher production of ammonia with microcarriers coated with adhesive molecules (Cultispher S and Pronectin F) relative to the uncoated carriers (Cytodex 1 and Immobasil FS). Experiments where the DMEM medium was gradually replaced by the serum-free medium (CHO-SFM-II) revealed important advantages over media containing serum, not only for assay purposes, but also for purification of the disintegrin. Altogether these results demonstrate that cultures on microcarriers, especially on Pronectin F, show good potential for larger scale cultures of rCHO-K1 cell.

Biological characteristics of Chinese hamster ovary cells transfected with bovine Prnp

A normal prion protein (PrPc) is converted to a proteaseresistant isoform by an apparent self-propagating activity in transmissible spongiform encephalopathy, a neurodegenerative disease. The cDNA encoding open reading frame (ORF) of the bovine prion protein gene (Prnp) was cloned from Korean cattle by PCR, and was transfected into Chinese hamster ovary (CHO-K1) cells using lipofectamine. The gene expression of the cloned cDNA was confirmed by RT-PCR and Western blotting with the monoclonal antibody, 6H4. Cellular changes in the transfected CHO-K1 cells were investigated using parameters such as MTT, lactate dehydrogenase (LDH), and superoxide dismutase (SOD) activities, as well as nitric oxide (NO) production, and an apoptosis assay. In the MTT and LDH assays, the bovine PrnP-transfectant showed a lower proliferation rate than the wild-type (p < 0.05). Production of NO, after LPS or ConA stimulation, was not detected in either transfectants or CHO-K1 cells. In SOD assay under ConA stimulation, the SOD activity of transfectants was 10 times higher than that of CHO-K1 cells at 6 h after treatment (p < 0.05). The genomic DNA of both the transfectants and control cells began to be fragmented at 6 h after treatment with cyclohexamide. Caspase-3 activity was reduced by transfection with the bovine Prnp (p < 0.05). Conclusively, the viability of transfectants expressing exogenous bovine Prnp was decreased while the capacities for cellular protection against antioxidative stress and apoptosis were increased.

Expression of Recombinant sPDGFR?-Fc in CHO and Its Anti-proliferation Analysis / 中国生物工程杂志

Orjective:To obtain recombinant CHO-K1 with expressing sPDGFR? and to identify the biological activities of sPDGFR? secreted in non-serum medium.Methods:Recombinant human sPDGFR? expression vector pIRES-Neo3-sPDGFR?-Fc was constructed and then transfected into CHO-K1 cells by using LipofectamineTM 2000.After screened with G418 in 8 weeks,some monoclone cells were selected randomly to amplify in 96-well-plate to 24-well-plates,and then to identify positive cell clones by RT-PCR.Furthermore,the candidate cell clones were test by Real-Time PCR and Western blot assays.Finally,anti-proliferation activities of the expressed sPDGFR? were analyzed by MTT.Results:sPDGFR?-Fc was cloned into pIRES-Neo3 correctly.The sPDGFR?-Fc expression level in recombinant CHO-K1 cell clones were concordant in between Realtime PCR and Western blot assay.sPDGFR?-Fc obtained from cultured non-serum medium of positive CHO-K1 could significantly inhibit proliferation of vascular endothelial cell.Conclusion:Successed to select recombinant CHO-K1 cell lines with high expressed sPDGFR?-Fc.The sPDGFR?-Fc can inhibit the cell proliferation significantly and it means sPDGFR?-Fc might be a new anti-cancer drug in the future.

Establishment and application of the engineered cells expressing a human G-protein-coupled receptor c / 中国药理学通报

Aim To establish a screening system of orphan G protein-coupled receptors (oGPCRs) for their ligands based on monitoring [Ca 2+]_i in engineered cells. Methods The whole ORF of a member of human oGPCR, designated human G-protein-coupled receptor c (hGPCRc), was amplified by RT-PCR from human colon tissue and its structure was analyzed with softwares. CHO-K_1 cells were transfected with the recombinant pcDNA 3.1(+)-hGPCRc to obtain engineered CHO-hGPCRc cells. As fluorescence probe, Fluo-3 was used in assaying the [Ca 2+]_i changes induced by different compounds in the CHO- hGPCRc cells.Results Bioinformatic analysis showed that hGPCRc was localized at 13q32.2, and its corresponding amino acids formed seven-transmembrane domains and was close to human P2Y_1 receptor. It was indicated that hGPCRc was a new member of human GPCR. CHO- hGPCRc cells expressing hGPCRc were obtained successfully but no one was able to activate hGPCRc among the tested compounds indicated by the [Ca 2+]_i changes. Conclusion Although hGPCRc was even though close to human P2Y_1 receptor, it can not be activated by the known compounds which activate the P2Y_1 receptor. hGPCRc might be a new member of purine receptor family but dose not belong to P2Y_1 subfamily.