Efficient production process of bioactive recombinant human leukemia inhibitory factor in Chinese hamster ovary cells

The rhLIF is widely used as an essential factor in stem cell cultures for cell therapies. However, all the recombinant LIFs commercially available are expensive, and no commercially available rhLIF meet the standards recommended by USP for use in cell therapies. The current study reports the efficient production of N-glycosylated and bioactive rhLIF in CHO cells. The production rate of established rhLIF-expressing rCHO cells was approximately 0.85 g/l in 12-day fed-batch cultures using a 7.5 l bioreactor. The rhLIF protein was purified via a four-step purification procedure with approximately 57% recovery rate and greater than 99% purity. The purified rhLIF was N-glycosylated and biologically active with an EC₅₀ of 0.167 ng/ml and a specific activity of 0.86 × 10³ IU/mg. The purification procedure controlled the levels of process-related impurities below critical levels recommended by USP for cytokines used in cell therapies. The current work is the first production process of N-glycosylated and bioactive rhLIF, which can be applied to large-scale manufacture of GMP-grade rhLIF for use as an ancillary material in cell therapy.

A Kelch domain-containing KLHDC7B and a long non-coding RNA ST8SIA6-AS1 act oppositely on breast cancer cell proliferation via the interferon signaling pathway

In our previous study, the Kelch domain-containing 7B (KLHDC7B) was revealed to be hypermethylated at the promoter but upregulated in breast cancer. In this study, we identified a long non-coding RNA, ST8SIA6-AS1 (STAR1), whose expression was significantly associated with KLHDC7B in breast cancer (R2 = 0.3466, P < 0.01). Involvement of the two genes in tumorigenesis was examined via monitoring their effect on cellular as well as molecular events after each gene dysregulation in cultured mammary cell lines. Apoptosis of MCF-7 decreased by 49.5% and increased by 33.1%, while proliferation noted increase and decrease by up- and downregulation of KLHDC7B, respectively, suggesting its oncogenic property. STAR1, however, suppressed cell migration and increased apoptosis. Network analysis identified many target genes that appeared to have similar regulation, especially in relation to the interferon signaling pathway. Concordantly, expression of genes such as IFITs, STATs, and IL-29 in that pathway was affected by KLHDC7B and STAR1. Taken together, KLHDC7B and STAR1 are both overexpressed in breast cancer and significantly associated with gene modulation activity in the interferon signaling pathway during breast tumorigenesis.

SCTR regulates cell cycle-related genes toward anti-proliferation in normal breast cells while having pro-proliferation activity in breast cancer cells

Secretin receptor (SCTR), the G-protein coupled receptor (GPCR) for secretin, has been observed to be upregulated in a few tumor types while downregulated in others, promoting or suppressing the proliferation of tumor cells, respectively. However, little is known about the molecular regulatory mechanism of dysregulation in cancer. In the present study, an analysis of the biological pathways affected by methylation in breast cancer using the methylome databases revealed that GPCRs played a major part in the affected pathway. SCTR, one of the dysregulated GPCRs, showed hypermethylation (p<0.01) and downregulation (p<0.05) in breast cancer tissues. Pathway analysis after the downregulation of SCTR by siRNA in MCF-10A cells identified the G2/M stage checkpoint as the top-scored pathway. Cell cycle-related genes were all upregulated or downregulated suppressing cell proliferation. However, the overexpression of SCTR in MCF-7 cells led to a 35% increase of the cell proliferation index and 2.1-fold increase of cellular migration. Our findings indicate that SCTR suppresses the proliferation of normal breast cells, while the gene stimulates the proliferation and migration of cancer cells being downregulated by promoter methylation.

Nuclear-encoded mitochondrial MTO1 and MRPL41 are regulated in an opposite epigenetic mode based on estrogen receptor status in breast cancer

BACKGROUND

MTO1 and MRPL41 are nuclear-encoded mitochondrial genes encoding a mitochondrial tRNA-modifying enzyme and a mitochondrial ribosomal protein, respectively. Although both genes have been known to have potential roles in cancer, little is known about their molecular regulatory mechanism, particularly from an epigenetic approach. In this study, we aimed to address their epigenetic regulation through the estrogen receptor (ER) in breast cancer.

METHODS

Digital differential display (DDD) was conducted to identify mammary gland-specific gene candidates including MTO1 and MRPL41. Promoter CpG methylation and expression in breast cancer cell lines and tissues were examined by methylation-specific PCR and real time RT-PCR. Effect of estradiol (E2), tamoxifen, and trichostatin A (TSA) on gene expression was examined in ER + and ER- breast cancer cell lines. Chromatin immunoprecipitation and luciferase reporter assay were performed to identify binding and influencing of the ER to the promoters.

RESULTS

Examination of both cancer tissues and cell lines revealed that the two genes showed an opposite expression pattern according to ER status; higher expression of MTO1 and MRPL41 in ER- and ER+ cancer types, respectively, and their expression levels were inversely correlated with promoter methylation. Tamoxifen, E2, and TSA upregulated MTO1 expression only in ER+ cells with no significant changes in ER- cells. However, these chemicals upregulated MRPL41 expression only in ER- cells without significant changes in ER+ cells, except for tamoxifen that induced downregulation. Chromatin immunoprecipitation and luciferase reporter assay identified binding and influencing of the ER to the promoters and the binding profiles were differentially regulated in ER+ and ER- cells.

CONCLUSIONS

These results indicate that different epigenetic status including promoter methylation and different responses through the ER are involved in the differential expression of MTO1 and MRPL41 in breast cancer.

Stage-specific methylome screen identifies that NEFL is downregulated by promoter hypermethylation in breast cancer

Aberrant hypermethylation of promoter regions in specific genes is a key event in the formation and progression of breast cancers, and an increasing number of marker genes have been identified. However, few genes which show methylation change in accordance with the progression of breast cancer have been identified. To identify genes which consistently undergo promoter methylation alterations as the tumor develops from a benign to a malignant form, genome-wide methylation databases of breast cancer cell lines from stage I to stage IV were analyzed. Heatmap and cluster analysis revealed that the genome-wide methylation changes showed a good accordance with tumor progression. Seven out of 14,495 genes were found to be consistently increased alongside the promoter methylation level through the normal cell line to the cancer stage IV cell lines. NEFL, one of the in silico hypermethylated genes in cancer, showed hypermethylation and lower expression in the cancer cell line MDA-MB-231, as well as in cancer tissues (methylation, p<0.05; expression, p<0.01). The expression was restored by inducing demethylation of the promoter in MDA-MB-231 cells. Our findings may lend credence to the possibility of using tumor stage-specific alterations in methylation patterns as biomarkers for estimating prognosis and assessing treatment options for breast cancer.

Vessel Boundary Detection for its 3D Reconstruction by Using a Deformable Model (GVF Snake)

Vessel boundary detection and 3D modeling is a difficult but necessary task in analyzing the mechanics of inflammation and the structure of the microvasculature. We present in this paper a method of analyzing this structure by the means of the deformable model (using GVF Snake) for vessel boundary detection and three-dimensional reconstruction. For this purpose, we used a virtual vessel model and produced synthetic images. From these images, we obtained contours of vessels by the GVF Snake and then reconstructed a three-dimensional structure by using the coordinates of the Snakes.

FIP200 inhibits β-catenin-mediated transcription by promoting APC-independent β-catenin ubiquitination

Focal adhesion kinase-family-interacting protein of 200 kDa (FIP200) has been shown to regulate multiple cellular functions, including cell adhesion, autophagy, development and proliferation. Furthermore, FIP200 is considered to have tumor-suppressive activity, which may be correlated with its inactivation in human breast cancers, in addition to its role as an important signal transduction node. Herein, we report that FIP200 interacts with the oncoprotein β-catenin. Moreover, FIP200 promotes destabilization of wild-type β-catenin, but not a cancer-causing form of β-catenin, and as a result represses the β-catenin-mediated transcription. FIP200-induced degradation of β-catenin is independent of adenomatous polyposis coli (APC) of the well-established β-catenin destruction complex (glycogen synthase kinase-3β/axin/APC), in a component of β-catenin E3 ubiquitin ligase, β-TrCP-dependent manner. Thus, the APC-independent β-catenin degradation by FIP200 suggests a role for FIP200 in tumor suppression in the presence of APC dysfunction. These findings reveal a new and important function of FIP200 in regulation of the Wnt/β-catenin pathway.

Immunomodulatory effects of specific bacterial components of Lactobacillus plantarum KFCC11389P on the murine macrophage cell line RAW 264.7

AIMS

The objective of this study was to investigate the ability of specific bacterial components of Lactobacillus plantarum KFCC11389P to induce anti-inflammatory mediators in cell cultures of the murine macrophage cell line, RAW 264.7.

METHODS AND RESULTS

The RAW 264.7 cells were stimulated with viable bacterial cells (VC), heat-killed (HK) cells, cell walls (CW) or ultrafiltrates of metabolic products (UF). An increase in the levels of tumour necrosis factor (TNF)-alpha was observed in VC, HK and CW, but this effect was much lower in UF. VC stimulated higher levels of interleukin (IL)-6 releases as well as nitric oxide production than HK. In contrast, UF and its separated molecule, fraction 4, were much strong IL-10 inducers. Fraction 4 (8.1 kDa), especially, inhibited the production of pro-inflammatory cytokines, IL-6 (89% decrease) and TNF-alpha (55% decrease), in lipopolysaccharide (LPS)-stimulated murine macrophages.

CONCLUSIONS

The results of this study indicate that metabolic products of Lact. plantarum KFCC11389P could influence the immune-modulating activity via IL-10, and pretreatment with this specific molecule could inhibit LPS-induced release of IL-6 and TNF-alpha.

SIGNIFICANCE AND IMPACT OF THE STUDY

Our findings suggest that the specific molecules of Lact. plantarum KFCC11389P may be useful for the treatment of acute inflammatory responses such as Crohn's disease or ulcerative colitis.

A Polynomial Approximation Approach for Analyzing ST Shape Change

ST segment is the most important diagnostic parameter to finding myocardial ischemia. Generally physicians make theirs effort to find the change of ST level and shape in ECG to diagnose myocardial ischemia. Most of algorithms that have been developed until now place importance on the ST segment depression and elevation. However, ST change in shape is also good parameter to find a heart disease and it should be considered prudently. The aim of this study is to detect the change of ST in shape using a polynomial approximation method. The developed algorithm finds the least squares curve for the data between S wave and T wave in ECG and calculates the variance of ST shape. An approximate curve of ST is represented by one polynomial over the whole ST or three polynomials for the segmented ST by three parts. The algorithm considers only the relative change of ST shape based on the reference ST, normal shape typically. From the results of the developed algorithm, we can acquire visually the information about the place to include the change of ST shape in the test ECG provided by European ST database.

Non-surgical management of microperforation induced by EMR of the stomach

BACKGROUND

Perforation and bleeding are major complications associated with gastric endoscopic mucosal resection. Evident perforation during endoscopic mucosal resection can be managed by endoscopic clipping. However, management of microperforation is not well established.

PATIENT AND METHOD

From January 2002 to June 2004, 109 early gastric cancers and 300 adenomas were treated with endoscopic mucosal resection. Iatrogenic perforations occurred in 4.16% (n=17) patients. Following exclusion of four evident perforations, microperforation was observed in 3.18% (n=13) patients. The clinical features of microperforation in patients were retrospectively reviewed.

RESULTS

In a total of 13 microperforation cases, 2 patients were managed surgically. The remaining patients successfully recovered without surgical management. In the case of 11 patients without surgery, 7 experienced abdominal pain, which required analgesics, 2 patients experienced mild discomfort and 2 patients experienced no symptoms. A body temperature above 37.5 degrees C was observed in 9.1% (n=1) patients and leucocytosis above 9000 microL-1 was in 72.7% (n=8) patients. The mean duration of nasogastric tube drainage was 2.36+/-1.03 days, of fasting 4.18+/-1.17 days, of intravenous antibiotics 5.55+/-1.44 days and of hospitalisation 7.45+/-1.04 days.

CONCLUSION

Microperforation induced by gastric endoscopic mucosal resection can be managed successfully using a non-surgical approach including fasting, nasogastric tube drainage and intravenous antibiotics.

Genetics of female functional virginity in the parthenogenesis-Wolbachia infected parasitoid wasp Telenomus nawai (Hymenoptera: Scelionidae)

A lepidopteran egg parasitoid species Telenomus nawai consists of two distinct populations with different reproductive modes. One is a completely thelytokous population consisting of females only, whereas the other displays arrhenotokous reproduction where fertilized eggs develop into diploid females and unfertilized eggs into haploid males. Thelytoky in T. nawai is caused by a bacterial symbiont, the parthenogenesis-inducing (PI) Wolbachia. Recent theoretical studies have shown that when a PI-Wolbachia is spreading in a population, mutations that allow uninfected females to produce more male offspring will spread rapidly eventually becoming fixed. The consequence of such a mutation is that sexual reproduction is no longer successful in infected females. Here we determine the genetic basis of the females' inability to reproduce sexually by introgressing the genome of a thelytokous line into an arrhenotokous line. The results suggest that the mutations are recessive and inherited either as a single-locus major gene with some modifiers, or as two partially linked loci.

Deficiency of D-erythroascorbic acid attenuates hyphal growth and virulence of Candida albicans

In some lower eukaryotes, D-erythroascorbic acid, a five-carbon analog of L-ascorbic acid, is present instead of L-ascorbic acid. We have cloned ALO1, the gene encoding D-arabinono-1,4-lactone oxidase, which catalyzes the final step of D-erythroascorbic acid biosynthesis in Candida albicans. The ALO1 gene contained a continuous open reading frame of 1,671 bp that encodes a polypeptide consisting of 557 amino acids with a calculated molecular mass of 63,428 Da. To investigate the functional roles of D-erythroascorbic acid in C. albicans, we disrupted or overexpressed the ALO1 gene. In the alo1/alo1 null mutants, the activity of D-arabinono-1,4-lactone oxidase was completely lost and D-erythroascorbic acid could not be detected. When ALO1 on a multicopy plasmid was transformed in C. albicans, the enzyme activity and the intracellular D-erythroascorbic acid level were increased up to 3.4-fold and 4.0-fold, respectively. The alo1/alo1 null mutants of C. albicans showed increased sensitivity towards oxidative stress. Overexpression of ALO1 made the cells more resistant to the same stress. The alo1/alo1 mutants showed defective hyphal growth and attenuated virulence. Taken together, our results suggest that D-erythroascorbic acid functions as an important antioxidant and can be considered one of the virulence factors enhancing the pathogenicity of C. albicans.

Even-odd alternation in mass spectrum of thymine and uracil clusters: evidence of intracluster photodimerization

Multiphoton ionization of thymine and uracil clusters generated by a supersonic molecular beam gave rise to a remarkable alternation of mass spectral intensities between even- and odd-numbered clusters. Such alternation was observed in clusters of up to 30 molecules. Excitation to the two lowest electronically excited states seemed to be a strong prerequisite. In view of the well known photodimerization reaction of thymine and uracil in the bulk phase, it is proposed that such alternation in the mass spectral intensity resulted from formation of photodimer units within the cluster on intense UV irradiation. Several analogues of thymine with no known propensity for photodimerization in the bulk phase did not exhibit any sign of such alternation in the cluster mass spectrum. The intrinsic UV window for photodimerization, and hence photoinduced mammalian mutagenesis, was estimated to be approximately 210-280 nm, significantly narrower than the previously reported bulk values of 150-300 nm.

Monoclonal antibodies raised against infectious haematopoietic necrosis virus (IHNV) G protein and a cellular 90 kDa protein neutralize IHNV infection in vitro

Immune sera were obtained from four rainbow trout that had survived natural infection by infectious haematopoietic necrosis virus (IHNV), and five monoclonal antibodies (MAbs) were prepared against a Korean isolate of IHNV, IHNV-PRT. These immune sera and MAbs were characterized in terms of IHNV-neutralizing properties and reactivity in Western blots with the viral proteins of IHNV-PRT. All five MAbs and four immune sera neutralized IHNV-PRT to various extents. Antibodies in these immune sera recognized two structural proteins of IHNV, G and M1, and one protein with a molecular mass of 90 kDa. Of the five MAbs, three (AB9, AF6 and AG6) recognized the IHNV G protein, and the other two (AB7 and BC2) recognized the 90 kDa protein. The 90 kDa protein was found to be a cellular protein constitutively expressed at low levels in fish cells and expression of this protein was augmented by infection with IHNV and heat shock. MAbs specific to four stress proteins, hsp60, hsp70, hsp90 and grp94, failed to bind to this 90 kDa protein. MAbs AB9 and AB7 reacted fairly broadly with six different IHNV strains. Together, these results indicate that (1) two IHNV proteins, G and M1, and a 90 kDa cellular protein are immunogenic, (2) G and the 90 kDa proteins contain neutralizing epitopes, and (3) the epitopes recognized by MAbs AB9 and AB7 are conserved among the six different IHNV strains.

Single electron transfer by an extracellular laccase from the white-rot fungus Pleurotus ostreatus

Two different bands with laccase activity were obtained after nondenaturing PAGE of the culture filtrate of Pleurotus ostreatus. Immunoblot analysis revealed that antisera raised against laccase I were not reactive to laccase II. Laccase I, which exhibited faster mobility on nondenaturing polyacrylamide gel, was purified 42.9-fold with an overall yield of 10.8%. Gel filtration and SDS-PAGE revealed that laccase I is a single polypeptide with a molecular mass of approximately 64 kDa. Laccase I contained 12.5% carbohydrate by weight and 3.9 mol copper (mol protein)-1. The absorption spectrum of laccase I showed a type 1 signal at 605 nm and EPR spectra showed that the parameters of the type 1 and type 2 Cu signals were g parallel = 2.197 and A parallel = 0.009 cm-1, and g parallel = 2.263 and A parallel = 0.0176 cm-1, respectively. The data obtained from the pH profiles suggested that two ionization groups, whose pKa values were 5.60-5.70 and 6.70-6.85, may play an important role in the active site of laccase I as the ligand of copper metal. The optimal pH and temperature for the activity of laccase I were 6.0-6.5 and 30-35 degrees C, respectively. The enzyme had affinity for various lignin-related phenolic compounds: the Km values for ferulic acid and syringic acid were 48 and 89 microM, respectively. EPR spectroscopic study of the action of laccase I on 3,5-dimethoxy-5-hydroxyacetophenone indicated that this enzyme catalyses single electron transfer with the formation of the phenoxy radical as an intermediate.

Independent regulation of B-cell inducing factor and IL-2 production by T lymphocytes, and direct and indirect promotion of immunoglobulin secretion by glucocorticosteroid

The conditions for induction of B-cell inducing factor (BIF) by human peripheral blood T cells was investigated. BIF was assayed by induction of immunoglobulin secreting cells (ISC) in peripheral blood B (non-T) cells stimulated with Staphylococcus aureus bacteria strain Cowan I (Sac), and in the IgM cell line SKW6.4. Maximum BIF production occurred with high concentrations of the T-cell mitogens phytohemagglutinin, concanavalin A, and PWM. Dexamethasone (Dex) also induced BIF production in T cells at 10(-5) to 10(-7) M. At 10(-5) and 10(-6) M Dex, the T-cell supernatants had to be dialyzed before testing because Dex alone stimulated variable levels of ISC in both test B-cell assays. Dex did not enhance BIF production by T cells that were optimally stimulated by lectin. BIF levels were maximum by Day 2 of T-cell cultures and remained high at Days 3 and 4. In contrast, IL-2 reached a peak at Day 1 and declined drastically by Day 4. We previously showed that IL-2 at less than 100 U/ml did not induce ISC in B cells and did not alter ISC induction by BIF. Dex did not induce IL-2 production and inhibited IL-2 production induced by Con A, in contrast to the promoting effects of Dex on BIF production, providing further evidence for the independence of BIF and IL-2 production and B-cell stimulation.

Rescue of IgM, IgG, and IgA production in common varied immunodeficiency by T cell-independent stimulation with Epstein-Barr virus

We previously defined three categories of B-cell defects in common varied immunodeficiency (CVI): failure to produce IgG and IgA in response to T cell-dependent (TD) stimulation by Staphylococcus bacteria (Sac) plus pokeweed mitogen or B-cell inducing factor (BIF), failure to produce any immunoglobulin, and failure of Sac-induced proliferation and differentiation. The present study includes the responses of 22 CVI patients to T cell-independent (TI) stimulation by Epstein-Barr virus (EBV). In the majority of patients, EBV-stimulated B cells showed normal proliferation and IgM production. In addition, IgG and IgA production was in the range of that for EBV-stimulated normal cells in many patients. Among 11 patients with no TD production of immunoglobulin of any isotype, two showed normal IgM secretion in response to EBV and five others had significant but subnormal responses. Four patients never had humoral responses despite repeated testing and removal of potentially suppressing T cells and monocytes. Concanavalin A stimulation of the T cells from all the patients tested resulted in the production of B-cell inducing factor at higher levels than for normal donor T cells, as assayed on normal Sac-stimulated B cells. These results show that many cases of B-cell defects in CVI patients involving TD production of IgM, switching to TD production of IgG and IgA, and mitogen responses to Sac are not absolute defects. The B cells will respond normally to some stimuli.

Stimulation of immunoglobulin secretion in human B lymphocytes as a direct effect of high concentrations of IL 2

In certain human IgM and IgG cell lines, immunoglobulin (Ig) secretion is highly stimulated by a B cell inducing factor (BIF) that is free of interleukin 2 (IL 2). BIF also induces Ig secretion in purified peripheral blood B cell populations that have been mitogenically stimulated by Staphylococcus aureus bacteria. Low concentrations of IL 2 (less than 20 U/ml) are not active in these systems. We now show that IL 2 at concentrations above 100 U/ml can induce Ig secretion in these blood B cells and B cell lines. Both conventional IL 2, purified from the human JURKAT and gibbon MLA-144 cell lines, and recombinant IL 2 are active. Very high concentrations approaching 10(4) U/ml are optimal for Ig secretion. Antibody to the T cell IL 2 receptor, anti-Tac, did not inhibit stimulation of the IgM cell line SKW6.4 by IL 2, and no Tac antigen was detected on the cells. The 9B11 monoclonal anti-IL 2 antibody that neutralizes T cell growth activity also abrogates stimulation of Ig secretion by conventional and recombinant IL 2 in the SKW6.4 cell line. However, the 1H11 monoclonal anti-(conventional thr3-glycosylated IL 2), which does not neutralize T cell growth activity, does inhibit induction of Ig secretion by the corresponding IL 2 in the B cell line. These results suggest that IL 2 stimulates B cells via a low-affinity interaction with a receptor different from the Tac receptor identified on T cells, and that the active site on the IL 2 molecule for B cells differs from that for T cell targets. If IL 2 promotes Ig secretion by binding with a low affinity to the B cell BIF receptor, IL 2 and BIF could be homologous proteins.

Stimulation of immunoglobulin secretion in human B lymphocytes as a direct effect of high concentrations of IL 2

In certain human IgM and IgG cell lines, immunoglobulin (Ig) secretion is highly stimulated by a B cell inducing factor (BIF) that is free of interleukin 2 (IL 2). BIF also induces Ig secretion in purified peripheral blood B cell populations that have been mitogenically stimulated by Staphylococcus aureus bacteria. Low concentrations of IL 2 (less than 20 U/ml) are not active in these systems. We now show that IL 2 at concentrations above 100 U/ml can induce Ig secretion in these blood B cells and B cell lines. Both conventional IL 2, purified from the human JURKAT and gibbon MLA-144 cell lines, and recombinant IL 2 are active. Very high concentrations approaching 10(4) U/ml are optimal for Ig secretion. Antibody to the T cell IL 2 receptor, anti-Tac, did not inhibit stimulation of the IgM cell line SKW6.4 by IL 2, and no Tac antigen was detected on the cells. The 9B11 monoclonal anti-IL 2 antibody that neutralizes T cell growth activity also abrogates stimulation of Ig secretion by conventional and recombinant IL 2 in the SKW6.4 cell line. However, the 1H11 monoclonal anti-(conventional thr3-glycosylated IL 2), which does not neutralize T cell growth activity, does inhibit induction of Ig secretion by the corresponding IL 2 in the B cell line. These results suggest that IL 2 stimulates B cells via a low-affinity interaction with a receptor different from the Tac receptor identified on T cells, and that the active site on the IL 2 molecule for B cells differs from that for T cell targets. If IL 2 promotes Ig secretion by binding with a low affinity to the B cell BIF receptor, IL 2 and BIF could be homologous proteins.