Montreal, Canada
Montreal, Canada

Time filter

Source Type

Choi Y.H.,Institute of Molecular Biology and Genetics | Kim J.H.,Institute of Molecular Biology and Genetics | Kim D.-H.,Seoul National University | Jang K.-S.,Institute of Molecular Biology and Genetics | And 3 more authors.
Glycobiology | Year: 2014

In the large-quantity production of α2,3- and α2,6- sialyllactose (Neu5Ac(α2,3)Galβ1,4Glc (3′-SL) and Neu5Ac(α2,6)Galβ1,4Glc (6′-SL)) using sialyltransferases (STs), there are major hurdles to overcome for further improvement in yield and productivity of the enzyme reactions. Specifically, Pasteurella multocida α2,3-sialyltransferase (α2,3PST) forms a by-product to a certain extent, owing to its multifunctional activity at pH below 7.0, and Photobacterium damselae α2,6-sialyltransferase (α2,6PdST) shows relatively low ST activity. In this study, α2,3PST and α2,6PdST were successfully engineered using a hybrid approach that combines rational design with site-saturation mutagenesis. Narrowly focused on the substrate-binding pocket of the STs, putative functional residues were selected by multiple sequence alignment and alanine scanning, and subsequently subjected to site-saturation mutagenesis. In the case of α2,3PST, R313N single mutation improved its activity slightly (by a factor of 1.5), and further improvement was obtained by making the double mutants (R313N/T265S and R313H/T265S) resulting in an overall 2-fold improvement in its specific α2,3 ST activity, which is mainly caused by the increase in kcat. It was revealed that the R313 mutations to N, D, Y, H or T greatly reduced the α2,6 ST side-reaction activity of α2,3PST at below pH 7.0. In the case of α2,6PdST, single-mutation L433S/T and double-mutation I411T/L433T exhibited 3- and 5-fold enhancement of the α2,6 ST-specific activity compared with the wild-type, respectively, via increase in kcat values. Our results show a very good model system for enhancing ST activity and demonstrate that the generated mutants could be used efficiently for the mass production of 3′-SL and 6′-SL with enhanced productivity and yield. © The Author 2013.


Cai Q.,Shanghai University | Cai Q.,GeneChem | Zhang W.-J.,Shanghai University | Zhu Q.-Q.,Shanghai University | Chen Q.,Shanghai University
Food Chemistry | Year: 2016

The rAra h 2.02 was studied to determine the influence of heat treatment on its structure and core IgE-binding epitopes. The results of SDS-PAGE, Western blotting, MALDI-TOF-MS, and atomic force microscopy showed that the structure of rAra h 2.02 was altered after boiling (100 °C) or autoclaving (121 °C) for 20 min. Furthermore, some of the protein may be aggregated. Results of circular dichroism spectroscopy showed that the α-helices content was reduced, while β-turns and random coils were increased by 81% and 27%, respectively, after autoclaving. Antibodies of three core IgE-binding epitopes were used to determine the binding capacity of rAra h 2.02 after thermal processing by indirect ELISA. The results showed that the binding capacities of the three core IgE-binding epitopes were changed after different heat treatments. © 2016 Elsevier Ltd. All rights reserved.


PubMed | GeneChem and Convergent
Type: Journal Article | Journal: Glycoconjugate journal | Year: 2016

Epothilone A is a derivative of 16-membered polyketide natural product, which has comparable chemotherapeutic effect like taxol. Introduction of sialic acids to these chemotherapeutic agents could generate interesting therapeutic glycoconjugates with significant effects in clinical studies. Since, most of the organisms biosynthesize sialic acids in their cell surface, they are key mediators in cellular events (cell-cell recognition, cell-matrix interactions). Interaction between such therapeutic sugar parts and cellular polysaccharides could generate interesting result in drugs like epothilone A. Based on this hypothesis, epothilone A glucoside (epothilone A 6-O--D-glucoside) was further decorated by conjugating enzymatically galactose followed by sialic acids to generate epothilone A 7-O--D-glucopyranosyl, 4-O--D-galactoside i.e., lactosyl epothilone A (lac epoA) and two sialosides of epothilone A namely epothilone A 7-O--D-glucopyranosyl, 4-O--D-galactopyranosyl 3-O--N-acetyl neuraminic acid and epothilone A 7-O--D-glucopyranosyl, 4-O--D-galactopyranosyl 6-O--N-acetylneuraminic acid i.e., 3sialyllactosyl epothilone A: 3SL-epoA, and 6sialyllactosyl epothilone A: 6SL-epoA, respectively. These synthesized analogs were spectroscopically analyzed and elucidated, and biologically validated using HUVEC and HCT116 cancer cell lines.


Chen Z.,PLA Fourth Military Medical University | Zhang L.,PLA Fourth Military Medical University | Xia L.,PLA Fourth Military Medical University | Jin Y.,GeneChem | And 7 more authors.
Cancer Letters | Year: 2014

Understanding the mechanism underlying multidrug resistance and identifying effective targets that can overcome it is of critical importance. In this study, mRNA and miRNA expression profiling of the drug resistant sublines, SGC7901/VCR and SGC7901/ADR, and their parental gastric cancer cell line SGC7901 were performed. A significant number of genes and a limited subset of miRNAs were commonly dysregulated, which were further validated using qRT-PCR. GO and KEGG pathway analyses of the commonly dysregulated genes indicated that the MAPK signalling pathway may be involved in multidrug resistance, which was further validated using immunoblotting and MTT assay. Finally a primary multidrug resistance network in gastric cancer, consisting of the commonly dysregulated genes and miRNAs, was established and functional miRNA-mRNA pairs were identified. The commonly dysregulated genes and miRNAs identified in this study may represent good therapeutic targets and further study of these targets may increase our understanding of the mechanisms underlying multidrug resistance. © 2014 Elsevier Ireland Ltd.


Patent
GeneChem | Date: 2012-01-18

The present invention discloses the use of a human NLK gene and associated drugs thereof. The present invention discloses the use of the NLK gene for tumor treatment, tumor diagnosis and drug preparation. The present invention further constructs an isolated molecule that attenuates expression of the NLK gene of tumor cells, cells comprising the isolated molecule and a NLK interference lentivirus, and discloses the use thereof as well. The isolated molecule or the NLK interference lentivirus that attenuates expression of the NLK gene provided in the present invention can specifically attenuate expression of the human NLK gene, especially the lentivirus, can effectively infect target cells, efficiently inhibit the expression of the NLK gene in target cells, and inhibit the growth of tumor cells, thus has great significance in tumor treatment.


Patent
GeneChem | Date: 2016-04-20

The present invention relates to a method for preparing a sialic acid derivative, wherein the method is characterized in that a process of using N-acetyl-D-glucosamine to prepare CMP-M-acetylneuraminic acid and a process of combining sialic acid with galactose or a galactose derivative to prepare a sialic acid (neuraminic acid) derivative are performed together in one reactor. According to the present invention, a high-priced cytidine 5-monophosphoric acid (CMP) can be recycled in a reaction container, thereby reducing the amount of cytidine 5-monophosphoric acid (CMP) introduced into the reaction, producing a sialic acid derivative using low-priced N-acetyl-D-glucosamine and pyruvic acid as substrates, and producing the sialic acid derivative at higher efficiency.


Patent
GeneChem | Date: 2014-05-30

The present invention relates to a method for preparing a sialic acid derivative characterized by performing both of a process for preparing CMP-N-acetylneuraminic acid using N-acetyl-D-glucosamine and a process for preparing the sialic acid (neuraminic acid) derivative that combines a sialic acid with a galactose derivative or a lactose derivative, together, in one reactor. According to the method for preparing a sialic acid derivative of the present invention, expensive cytidine 5-monophosphate (CMP) is capable of being recycled in a reactor, such that an amount of the CMP introduced into the reactor may be reduced, and the sialic acid derivative is capable of being prepared at a significantly high efficiency by using cheap N-acetyl-D-glucosamine, and pyruvate as substrates.


The present invention discloses uses of the human ZFX gene and drugs associated therewith. Also disclosed are uses of the human ZFX gene in tumor treatment, tumor diagnosis, and drug preparation. Further disclosed are small interfering RNA (siRNA), and nucleic acid and lentivirus encoding the siRNA to the human ZFX gene and uses thereof. The siRNA and nucleic acid and lentivirus encoding the siRNA provided by the present invention can specifically inhibit the expression of human ZFX gene. Lentiviruses in particular can efficiently infect target cells, inhibit ZFX expression in target cells, and inhibit the growth of tumor cells, thus promote tumor apoptosis and have great significance in tumor treatment.


News Article | July 9, 2007
Site: venturebeat.com

Woburn, Mass.-based BioVex, a biotech working on new ways to attack cancer and infections, raised $22 million in a fifth funding round. Triathlon Medical Ventures led the round, joined by New Science Ventures, Forbion Capital Ventures, Avalon Ventures, Credit Agricole Private Equity, GeneChem Management, Innoven Partners and Scottish Equity Partners. BioVex is developing so-called oncolytic viruses, which are designed to infect and destroy tumor cells — long a promising but never-proven anti-cancer technique. The company put an unusual twist on the concept by adding a gene to a herpes simplex virus that expresses GM-CSF (granulocyte macrophage-colony stimulating factor), a molecule that stimulates a strong immune response. Ideally, this virus should infect tumor cells while leaving healthy cells alone, then hijack the tumor cells’ own internal machinery to manufacture GM-CSF, stimulating an immune response that should also be directed at the tumor cells. That experimental drug, OncoVex GM-CSF, is currently in mid-stage human tests against skin cancer and early tests against head and neck cancer. BioVex is also developing a vaccine against genital herpes. The company had filed to go public last year, but withdrew its proposed offering last October.

Loading GeneChem collaborators
Loading GeneChem collaborators