The role of EGFR MAbs C225 in breast cancer stem cells

e22093

Background: The epithermal growth factor receptor(EGFR) signaling pathways has been implicated in self-renewal of breast cancer stem cells. It has been proved that the EGFR tyrosine kinase inhibitor-gefitinib significantly decreased the mammosphere- forming efficiency(MFE) in ductal carcinoma in situ (DCIS) derived cancer cells. We investigated the response of breast cancer stem cells in breast cancer cell line MCF-7 to EGFR MAbs C225(cetuximab). Methods: Cells were used for nonadherent (i.e.,mammosphere) culture and were divided into four groups according to the different culture medium whether or not including exogenous EGF and MAbs C225. MFE was calculated as the number of mammospheres (≥60um) and was expressed as a percentage. We Compared the percentage of CD44+/CD24- cells from the four groups, and measured the levels of the Wnt and Notch-3 gene expression of the four groups. Results: There was no significant difference of MFE between groups. In the presence of exogenous EGF, MAbs C225 significantly decreased the MFE and the percentage of CD44+/CD24- cells of mammospheres compared with exogenous EGF alone(0.7% versus 1.5%, P < 0.001 and 4% versus 11%P < 0.001;respectively). In the absence of exogenous EGF, MAbs C225 aslo statistically decreased the MFE and the percentage of CD44+/CD24- cells of mammospheres compared with that of lacking exogenous EGF and MAbs C225(0.53% versus 1.3%,P = 0.003 and 9% versus 3%, P < 0.01;respectively). And we observed that the Notch-3 gene expression was compensativly increased in the two groups of addition of MAb C225. No significant differences of Wnt gene expression were observed between groups. Conclusions: EGFR MAbs C225 could disrupt mammoshpere formation and decrease the percentage of CD44+/CD24- cells of mammoshpere cells. The expression of Notch-3 is increased with the EGFR antagonistics in breast cancer stem cells.

No significant financial relationships to disclose.

Screening of medicinal plants from Reunion Island for antimalarial and cytotoxic activity

AIM OF THE STUDY

Nine plants from Reunion Island, selected using ethnopharmacology and chemotaxonomy, were investigated for their potential antimalarial value.

MATERIALS AND METHODS

Thirty-eight extracts were prepared by maceration using CH(2)Cl(2) and MeOH, and were tested for in vitro activity against the 3D7 and W2 strain of Plasmodium falciparum. The most active extracts were then tested for in vitro cytotoxicity on human WI-38 fibroblasts to determine the selectivity index. Those extracts were also investigated in vivo against Plasmodium berghei infected mice.

RESULTS

Most active of the extracts tested were the dichloromethane leaves extracts of Nuxia verticillata Lam. (Buddlejaceae), Psiadia arguta Voigt. (Asteraceae), Lantana camara L. (Verbenaceae), the methanol extracts from Aphloia theiformis (Vahl) Benn. (Aphloiaceae) bark, and Terminalia bentzoe L. (Combretaceae) leaves displaying in vitro IC(50) values ranging from 5.7 to 14.1mug/ml. Extracts from Psiadia, Aphloia at 200mg/(kgday) and Teminalia at 50mg/(kgday) also exhibited significant (p<0.0005) parasite inhibition in mice: 75.5%, 65.6% and 83.5%, respectively.

CONCLUSION

Two plants showed interesting antimalarial activity with good selectivity: Aphloia theiformis and Terminalia bentzoe. Nuxia verticillata still needs to be tested in vivo, with a new batch of plant material.

Estrogen modulates cytokine expression in human periodontal ligament cells

Although systemic bone loss accompanying estrogen deficiency has been proposed as a risk factor for periodontal disease in post-menopausal women, the mechanisms involved remain unclear. The objective of this study was to elucidate the potential bone-sparing effect of estrogen (17beta-estradiol, E(2)) via modulation of inflammatory cytokine production in human periodontal ligament (hPDL) cells. E. coli lipopolysaccharide (LPS) increased the production of pro-inflammatory cytokines TNF-alpha, IL-1beta, IL-6, and receptor activator of NF- B ligand (RANKL) by hPDL cells at both mRNA and protein levels. E(2) treatment reversed the stimulatory effects of LPS on pro-inflammatory cytokine expression by hPDL cells. Moreover, E(2) up-regulated osteoprotegerin (OPG) expression and therefore attenuated the reduction of the OPG vs. RANKL ratio. Our results suggested that estrogen may play a significant role in modulating periodontal tissue responses to LPS, and may exert its bone-sparing effects on periodontal tissues via altering the expression of inflammatory cytokines in hPDL cells.

The expression of estrogen receptors and the effects of estrogen on human periodontal ligament cells

Osteoporotic women exhibit high frequency of alveolar bone loss and low bone density. Estrogen deficiency, which is vital in the pathogenesis of postmenopausal osteoporosis, has received increasing attention in the studies related to the periodontal diseases. Similar to most hormones, estrogen exerts its influence by binding to specific receptors, estrogen receptor (ER)-alpha and -beta. The periodontal ligament cells (PDLcs) are very important in maintaining the integrity of the periodontal tissue, which is the connective tissue located between the alveolar bone and the root surface of tooth. In this study, we evaluated the effects of estrogen deficiency on the alveolar bone in ovariectomized rats by histometric measurement of attachment level in vivo. Using the reverse transcriptase polymerase chain reaction (RT-PCR) and Western-blot procedure, we also detected mRNA and protein products of ERs and investigated the effects of estrogen on bone-forming capability by monitoring alkaline phosphatase (ALP) activity and osteocalcin production in cultured human PDLcs. Our results demonstrated that both ER-alpha and -beta were expressed in PDLcs. Moreover, when exposed to 17-beta estradiol, PDLcs exhibited positive modulation on ALP activity and osteocalcin production. The study suggests that estrogen and ERs may play an important role in periodontal diseases.

Expression of fibroblast growth factor-8 and regulation of cognate receptors, fibroblast growth factor receptor-3c and -4, in bovine antral follicles

Paracrine cell signaling is believed to be important for ovarian follicle development, and a role for some members of the fibroblast growth factor (FGF) family has been suggested. In the present study, we tested the hypothesis that FGF-8 and its cognate receptors (FGFR3c and FGFR4) are expressed in bovine antral follicles. RT-PCR was used to analyze bovine Fgf8, Fgfr3c and Fgfr4 mRNA levels in oocytes, and granulosa and theca cells. Fgf8 expression was detected in oocytes and in granulosa and theca cells; this expression pattern differs from that reported in rodents. Granulosa and theca cells, but not oocytes, expressed Fgfr3c, and expression in granulosa cells increased significantly with follicle estradiol content, a major indicator of follicle health. Fgfr4 expression was restricted to theca cells in the follicle, and decreased significantly with increasing follicle size. To investigate the potential regulation of Fgfr3c expression in the bovine granulosa, cells were cultured in serum-free medium with FSH or IGF-I; gene expression was upregulated by FSH but not by IGF-I. The FSH-responsive and developmentally regulated patterns of Fgfr3c mRNA expression suggest that this receptor is a potential mediator of paracrine signaling to granulosa cells during antral follicle growth in cattle.

Effects of human soluble BAFF synthesized in Escherichia coli on CD4+ and CD8+ T lymphocytes as well as NK cells in mice

B cell-activating factor belonging to the TNF family (BAFF, also called BLyS, TALL-1, zTNF-4, or THANK) is an important survival factor for B lymphocytes. In this study, we injected mouse abdominal cavity with human soluble BAFF (hsBAFF, 0.01, 0.1, 0.5, 2 mg/kg body mass) synthesized in Escherichia coli. On the 8th day after injection, we investigated the effects of hsBAFF on immune functional activities of splenic B lymphocytes, CD4(+) and CD8(+) T lymphocytes and natural killer (NK) cells in mice. The results showed that B lymphocyte proliferation significantly increased in hsBAFF-treated groups with dosages of 0.1 mg/kg (p<0.05), 0.5 and 2 mg/kg (p<0.01). We observed a dose-dependent increase of CD4(+) T lymphocyte percentage and significantly higher values in 0.5 and 2 mg/kg hsBAFF-treated groups (p<0.05 and p<0.001, respectively) compared to control group, but CD8(+) T lymphocyte percentage remained unchanged. The ratio of CD4(+) to CD8(+) T lymphocytes rose with increasing hsBAFF dosage (p<0.05 for 2 mg/kg hsBAFF vs. control). Significantly stronger NK cell activities were found in 0.5 and 2 mg/kg hsBAFF-treated groups (p<0.05). The main finding of this study is that the hsBAFF can enhance immune responses in the body by increasing B lymphocyte and CD4(+) T lymphocyte function as well as elevating NK cell activity.

A study of the phase behavior of a simple model of chiral molecules and enantiomeric mixtures

We present a study of the solid-fluid and solid-solid phase equilibrium for molecular models representative of chiral molecules and enantiomeric mixtures. The models consist of four hard sphere interaction sites of different diameters in a tetrahedral arrangement with the fifth hard sphere interaction site at the center of the tetrahedron. The volumetric properties and free energies of the pure enantiomers and binary mixtures were calculated in both fluid and solid phases using isobaric Monte Carlo simulations. The models exhibit essentially ideal solution behavior in the fluid phase with little chiral discrimination. In the solid phase the effects of chirality are much greater. Solid-fluid phase behavior involving the pure enantiomer solids and also racemic compounds was calculated. The calculations indicate that, depending on the relative sizes of the hard sphere interaction sites, packing effects alone can be sufficient to stabilize a racemic compound with respect to the pure enantiomer solids.

Platelet characteristic antigens of CD34+ cells in cryopreserved cord blood: a study of platelet-derived microparticles in transplant processing

BACKGROUND AND OBJECTIVES

In previous studies, we found that platelet microparticles (PMPs) bind to cord blood (CB) CD34+ cells and transfer adhesion molecules to them, which enhances their engraftment. Before applying this phenomenon in actual transplants, we investigated the effect of PMPs on cryopreserved CD34+ cells in CB.

MATERIALS AND METHODS

We cryopreserved 18 CB units, then evaluated the binding of PMPs to CD34+ cells after thawing, by varying the expression of platelet characteristic antigens (CD41a, CD61, CD62P and CXCR4) on these cells. Adherence of the CD34+ cells, coated with freeze/thaw-induced PMPs, to endothelium and fibronectin was also studied, as were the effects of thrombin-induced PMPs from both fresh and preserved CB platelets.

RESULTS

PMPs induced by freezing and thawing adhered less well to CD34+ cells than did those from fresh CB, and cells coated with these PMPs had poor adherence. However, thrombin-induced PMPs from both fresh and preserved CB platelets bound equally well to cryopreserved CD34+ cells and improved their adhesion properties.

CONCLUSIONS

PMPs could be a useful tool for enhancing engraftment after CB transplantation.

The dual-wave bolus feature in continuous subcutaneous insulin infusion pumps controls prolonged post-prandial hyperglycaemia better than standard bolus in Type 1 diabetes

The dual-wave bolus delivers a combination of an immediate normal pre-meal insulin bolus (approximately 3 min) followed by an extended (or square-wave) bolus that is evenly delivered over several hr as programmed by the patient. The purpose of this study was to compare post-prandial glycaemic excursions following a high-fat meal after administration of insulin by normal vs dual-wave bolus. During this prospective, cross-over, repeated measures study, subjects with diabetes and treated with insulin pump therapy were evaluated using the continuous glucose monitoring system (CGMS) following three combinations of meal and bolus type. A control meal or a high-fat meal was given in place of the evening meal on three separate occasions and comparisons were made between: a) the control meal with normal insulin bolus delivery, b) the high-fat meal with normal insulin bolus delivery, and c) the high-fat meal with dual-wave insulin bolus delivery. Although mean baseline CGMS values were similar in each of the three combinations of meal and bolus type (p=0.54) and in the three hr immediately following the meal (p=0.64, p=0.83, p=1.0), when compared to the control meal/normal bolus and high-fat meal/dual-wave bolus combinations, CGMS profiles disclosed significantly elevated post-prandial glucose in hr 5 through 14 (p<0.05) following the high-fat/normal bolus combination. Prolonged post-prandial glycaemic excursions are identified using the CGMS. Treating post-prandial hyperglycaemia with dual-wave insulin delivery may help manage chronic hyperglycaemia in patients with diabetes.

Molecular characterization of Asian maize inbred lines by multiple laboratories

This study focuses on the standardization of techniques across laboratories to enable multiple datasets to be compared and combined in order to obtain reliable and robust wide-scale patterns of diversity. A set of protocols using a core collection of simple sequence repeat (SSR) markers, reference lines and standard alleles, plus a common system of allele nomenclature, was adopted in the study of maize genetic diversity in a network of laboratories in Asia. Pair-wise allele comparisons of the reference lines, done to assess the general agreement between datasets from four laboratories, showed error rates (raw) ranging from 5.8% to 9.7%, which were reduced to less than 8% after adjustments of correctable errors, and further reduced to less than 6% after the exclusion of all markers with greater than 10% individual error rates. Overall, 45% of the total mismatches were due to frameshift errors, 39% to wrong allele size, 15% to failed amplification and 1% to "extra" alleles. Higher genetic similarity values of the reference lines were achieved using fewer markers with data of higher quality rather than with more markers of questionable quality. Cluster analysis of the merged datasets showed the lines from southern China to be highly diverse, falling into six of the seven clusters observed and all well represented by tester lines. The lines from Indonesia fell into five of six groups, with two main groups represented by tester lines. The CIMMYT lines developed for the Asian region showed a relatively narrow genetic base, falling in two out of seven and in three out of six clusters in China and Indonesia, respectively. In contrast to the case in southern China where 95% of the lines clustered separately from the CIMMYT lines, lines in the Indonesian breeding program show a closer relationship with the CIMMYT lines, reflecting a long history of germplasm exchange.

Solid–fluid and solid–solid phase equilibrium in a model of n-alkane mixtures

Solid-fluid and solid-solid phase equilibrium for binary mixtures of hard sphere chains modeling n-hexane, n-heptane, and n-octane has been calculated using Monte Carlo computer simulations. Thermodynamic integration was used to calculate the Gibbs free energy and chemical potentials in the solid and fluid phases from pure component reference values. A multiple stage free energy perturbation method was used to calculate the composition derivative of the Gibbs free energy. Equation of state and free energy data for the fluid phase indicate ideal solution behavior. Nonideality is much more significant in the solid phase with only partial solubility of shorter chains in the longer chains and essentially no solubility at the other end of the composition range. The miscibility decreases with increasing chain length difference between the components. For the model of n-hexane/n-octane mixtures solid--solid phase separation has been observed directly in some of the simulations, with the components segregating between the layers of the solid structure. The behavior is similar to that seen in some binary n-alkane mixtures with longer chain lengths but comparable chain length ratios between the components. Such phase separation, although indicated thermodynamically, is not seen directly in the simulations of the n-heptane/n-octane mixture due to the difference in the pure component crystal structures.

[Relationship between brain edema induced by freezing injury and concentration of Evan blues and cytosolic free calcium in brain tissues]

The authors studied the changes of Evan blues(EB) of brain tissues and concentration of cytosolic free calcium ([Ca2+]i), and relationship between them and water content of brain tissues following freezing brain edema in rats, to elucidate mechanism and type of brain edema induced by freezing injury. The results indicated that there were close positive relationship between water content and EB of brain tissues, and between [Ca2+]i and water content. We found that not only cytotoxic brain edema(intracellular edema) occurred but also occurred vasogenic brain edema(extracellular edema) followed by blood brain barrier breakdown after brain edema. Freezing brain edema is mixed brain edema.

Nutrient cycling in a tropical seasonal rain forest of Xishuangbanna, Southwest China. Part 1: tree species: nutrient distribution and uptake

Tropical rain forests are characterized by large numbers of the species with diverse growth habits. The objective of the present study was to determine the distribution of nutrient content in the major trees of the tropical rain forests in Xishuangbanna. This will improve the understanding of the nutrient losses from such sites that result from harvesting and flow of nutrients within the ecosystem and lead to the development of effective and rational forest management strategies. Based on the results in this study, the distribution of nutrients among biomass components of trees varied: The ordering of major elements concentrations was K > N > Mg > Ca > P in branch, stem and root tissues but was N > K > Mg > Ca > P in leaves. The maximum amount of all nutrients per ha occurred in the stems followed by branches, roots and leaves. Of the total uptake of 6167.7 kg ha(-1) of all nutrients, the contribution of various nutrients was found to be N (2010.6 t ha(-1)), P (196.3 t ha(-1)), K (2123.8 kg ha(-1)), Ca (832 kg ha(-1)) and Mg (1005 kg ha(-1)). However, comparing the nutrient uptake of other tropical and sub tropical forests, the results indicated that rates for the Xishuangbanna forests were 20-35% lower than previously reported values.