Enhanced tumor suppression in vitro and in vivo by co-expression of survivin-specific siRNA and wild-type p53 protein

The development of malignant prostate cancer involves multiple genetic alterations. For example, alterations in both survivin and p53 are reported to have crucial roles in prostate cancer progression. However, little is known regarding the interrelationships between p53 and survivin in prostate cancer. Our data demonstrate that the expression of survivin is inversely correlated with that of wtp53 protein (r(s)=0.548) in prostate cancer and in normal prostate tissues. We have developed a therapeutic strategy, in which two antitumor factors, small interfering RNA-survivin and p53 protein, are co-expressed from the same plasmid, and have examined their effects on the growth of PC3, an androgen-independent prostate cancer cell line. When p53 was expressed along with a survivin-specific short hairpin RNA (shRNA), tumor cell proliferation was significantly suppressed and apoptosis occurred. In addition, this combination also abrogated the expression of downstream target molecules such as cyclin-dependent kinase 4 and c-Myc, while enhancing the expression of GRIM19. These changes in gene expression occurred distinctly in the presence of survivin-shRNA/wtp53 compared with control or single treatment groups. Intratumoral injection of the co-expressed construct inhibited the growth and survival of tumor xenografts in a nude mouse model. These studies revealed evidence of an interaction between p53 and survivin proteins plus a complex signaling network operating downstream of the wtp53-survivin pathway that actively controls tumor cell proliferation, survival and apoptosis.

Integration of CO2 and odorant signals in the mouse olfactory bulb

Carbon dioxide (CO(2)) is an important environmental cue for many animal species. In both vertebrates and invertebrates, CO(2) is detected by a specialized subset of olfactory sensory neurons (OSNs) and mediates several stereotypical behaviors. It remains unknown how CO(2) cues are integrated with other olfactory signals in the mammalian olfactory bulb, the first stage of central olfactory processing. By recording from the mouse olfactory bulb in vivo, we found that CO(2)-activating neurons also respond selectively to odorants, many of which are putative mouse pheromones and natural odorants. In addition, many odorant-responsive bulbar neurons are inhibited by CO(2). For a substantial number of CO(2)-activating neurons, binary mixtures of CO(2) and a specific odorant produce responses that are distinct from those evoked by either CO(2) or the odorant alone. In addition, for a substantial number of CO(2)-inhibiting neurons, CO(2) addition can completely block the action potential firing of the cells to the odorants. These results indicate strong interaction between CO(2) signals and odorant signals in the olfactory bulb, suggesting important roles for the integration of these two signals in CO(2)-mediated behavioral responses.

Embryonic-like stem cell derived from adult bone marrow: immature morphology, cell surface markers, ultramicrostructure and differentiation into multinucleated fibers in vitro

Embryonic-like stem cell (ELSC), expressing part of surface markers of human embryonic stem cells, may be a better candidate for cell therapy of degenerative muscular disease than mesenchymal stem cell (MSC). We isolated ELSC and MSC from bone marrow, respectively, and compared their differences in the characteristics and the capacity of myogenic differentiation. Results showed that ELSC could be isolated successfully from 3 adult bone marrow samples by using serum-free medium with 10ng/ml basic fibroblast growth factor (bFGF). At the same cell density, MSC could also be isolated from the same samples by using DMEM/F12 medium containing 10% new cattle serum. However, ELSC appeared as small, morphologically slenderer, upregulated expression of SSEA-4 and ultramicroscopically more immature than MSC derived from the same samples. Immunofluorescent staining and RT-PCR analysis showed ELSC weakly expressed Oct-4, Nanog-3 and Sox-2. Moreover, ELSC and MSC could be induced into long, multinucleated fibers expressing myogenin and myosin heavy chain (MHC) in myogenic differentiation medium, but by day 10, proportion of multinucleated fibers positive for MHC was respectively 25.0%+/-6.9% and 13.8%+/-7.6% in ELSC and MSC culture. These data suggest that bone marrow derived ELSC represent an ideal candidate for cell therapy of degenerative muscular disease.

Mesenchymal stem cells inhibition of chronic ethanol-induced oxidative damage via upregulation of phosphatidylinositol-3-kinase/Akt and modulation of extracellular signal-regulated kinase 1/2 activation in PC12 cells and neurons

It is well known that chronic ethanol consumption damages CNS through oxidative stress which results in many dysfunctions. Recently, it has been demonstrated that as a promising strategy to treat several neurological diseases, transplanted bone marrow-derived mesenchymal stem cells (MSCs) can secrete lots of protective factors that in turn promote function recovery. In the present study, we assessed the potential effects of MSCs conditioned medium (MSC-CM) against chronic ethanol-associated damage on PC12 cells and primary cortical neurons. We found that pretreatment with MSC-CM notably improved cell survival, prevented chronic ethanol-associated apoptosis and abolished the robust deterioration in oxidative status. In addition, we also discovered that chronic ethanol exposure induced an inactivation of phosphatidylinositol-3-kinase (PI3K)/Akt and a lasting activation of extracellular signal-regulated kinase 1/2 (ERK1/2) in both PC12 cells and primary cortical neurons which were able to be reversed by MSC-CM. The PI3K inhibitor (LY294002) was able to reduce the antioxidative and cytoprotective effects conferred by MSC-CM, in part, and the ERK1/2 inhibitor (PD98059) was able to elicit significant protection from chronic ethanol cytotoxicity but not rescue the deterioration in oxidative status induced by chronic ethanol. Taken together, these findings provide the first evidence that MSCs might have potent antioxidant action to shield the apoptotic impairment from chronic ethanol exposure in PC12 cells and neurons, which is involved in upregulation of PI3K/Akt and modulation of ERK1/2 activation, at least partially.

Spatial and Temporal Incidences of Pineapple mealybug wilt-associated viruses in Pineapple Planting Blocks

A complex of Pineapple mealybug wilt-associated viruses (PMWaVs) that can infect pineapple (Ananas comosus) is correlated with reduced yields and mealybug wilt of pineapple. The incidences of PMWaV-1 and PMWaV-2 at planting, fruit harvest, the beginning of the ratoon crop, and ratoon fruit harvest were determined for end, side, and central regions of planting blocks in eight commercial fields. Differences in virus incidence for the three regions at ratoon harvest were highly significant (P = 0.0018). Central regions of planting blocks had lower virus incidences at the time of ratoon fruit harvest. Collection of propagation material from the central regions of planting blocks will help to minimize PMWaV incidence in fields planted with this material.

Invasive Lobular Carcinoma: Imaging Characteristics, Size at Presentation and Bilaterality

Aims: Invasive Lobular Carcinoma (ILC) is often described as elusive to standard imaging modalities and usually requiring mastectomy to obtain clear margins. Its reputation of being bilateral has been disputed by most recent studies. The aim of this study is to investigate whether the radiological diagnosis of ILC at first symptomatic presentation is more difficult than that of Invasive Ductal Carcinoma (IDC) in a modern breast clinic; also whether its size, surgical treatment at presentation and bilaterality is different from IDC and its subtypes.Materials & Methods: The radiological codes given to all new symptomatic patients with invasive breast cancer, presenting at the breast clinic of St Mary's Hospital and undergoing surgery as first treatment, (n=754), were collected prospectively between 1998 and 2005 and final mastectomy rates were also recorded. Histological reports of all synchronous and metachronous bilateral cancers presenting with at least one tumour between 1998 and 2007 were analyzed (n=65).Results: ILC was given suspicious radiological codes as often as IDC (90% vs 93%). On final histology, ILC measured on average 3.6cm compared to 2.5cm for IDC (p<0.05). There was a trend of ILC requiring mastectomy more often (51% vs 43%). 12.7% of patients with at least one ILC diagnosis have developed bilateral breast cancer compared to 4.5% of patients who have never had an ILC diagnosis (p<0.05).Results IDCILCMixedSpecialUnknownTotalNo of patients551 (73%)86 (11%)52 (7%)62 (8%)3 (0.4%)754Age (mean)5861596157.659Mastectomy191 (43%)36 (51%)23 (49%)13 (25%) 263Breast conservation257 (58%)36 (51%)24 (51%)41 (77%) 358Size cm (mean)2.53.62.52.0-2.7USS suspicious473 (93%)72 (90%)41 (90%)42 (76%)2 (100%)630MMG suspicious412 (81%)58 (73%)39 (80%)43 (80&)2 (100%)554 Conclusions: ILC is as easy to diagnose radiologically as IDC in symptomatic breast patients. However, ILC is larger at first presentation. In our database, ILC identified a subgroup of breast cancer patients who have a 3-fold higher risk of developing bilateral breast cancer of various histological types.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 4015.

Flk-1+ mesenchymal stem cells aggravate collagen-induced arthritis by up-regulating interleukin-6

The immunomodulatory ability of mesenchymal stem cells (MSCs) may be used to develop therapies for autoimmune diseases. Flk-1(+) MSCs are a population of MSCs with defined phenotype and their safety has been evaluated in Phase 1 clinical trials. We designed this study to evaluate whether Flk-1(+) MSCs conferred a therapeutic effect on collagen-induced arthritis (CIA), an animal model of rheumatic arthritis, and to explore the underlying mechanisms. Flk-1(+) MSCs, 1-2 x 10(6), were injected into CIA mice on either day 0 or day 21. The clinical course of arthritis was monitored. Serum cytokine profile was determined by cytometric bead array kit or enzyme-linked immunosorbent assay. Flk-1(+) MSCs and splenocytes co-culture was conducted to explore the underlying mechanisms. Flk-1(+) MSCs did not confer therapeutic benefits. Clinical symptom scores and histological evaluation suggested aggravation of arthritis in mice treated with MSCs at day 21. Serum cytokine profile analysis showed marked interleukin (IL)-6 secretion immediately after MSC administration. Results of in vitro culture of splenocytes confirmed that the addition of Flk-1(+) MSCs promoted splenocyte proliferation and increased IL-6 and IL-17 secretion. Moreover, splenocyte proliferation was also enhanced in mice treated with MSCs at day 21. Accordingly, MSCs at low concentrations were found to promote lipopolysaccharide-primed splenocytes proliferation in an in vitro co-culture system. We propose that Flk-1(+) MSCs aggravate arthritis in CIA model by at least up-regulating secretion of IL-6, which favours Th17 differentiation. When Flk-1(+) MSCs are used for patients, we should be cautious about subjects with rheumatoid arthritis.

The influence of exon 7 Phe389Leu polymorphism on P120 catenin interactions with E-cadherin and three-dimensional model rebuilt

The significance of endothelial P120 catenin (P120ctn) activity has been recognized for many years, however it was only recently that the complicated regulation of this constitutively expressed enzyme in endothelial cells was identified. A critical component of the P120ctn regulatory cycle in endothelial cells is its intracellular localization to caveolae. The caveolar coordination of P120ctn, more specifically its interaction with E-cadherin plays a major role in normal endothelial P120ctn activity and vascular bioavailability of nitric oxide. We have recently shown that the presence of P120ctn exon 7 Phe389Leu polymorphism caused diminished shear which was dependent catenin activation, was less extensively associated with caveolae, and had a decreased degree of interaction with E-cadherin. Here, we carried out preliminary investigations to identify possible mechanisms of the genotype-dependent endothelial cell responses we observed in our previous investigations. Through this approach we tested the hypothesis that computer simulations could provide insights regarding the contribution of this single nucleotide polymorphism to regulation of the P120ctn isoform. We observed that in the Phe/Leu and Leu/Leu mutant genotypes, the amount of P120ctn associated with E-cadherin was significantly lower. Additionally, we have shown, using a theoretical computational model, that mutation of an amino acid at position 389 might affect the protein-protein interactions and localization of the P120ctn protein. These alterations might also affect the protein function and explain the enhanced disease risk associated with the presence of Phe389Leu polymorphism in the P120ctn protein.

Effect of soft segment crystallization and hard segment physical crosslink on shape memory function in antibacterial segmented polyurethane ionomers

Shape memory polyurethane (SMPU) ionomers containing constant 75 wt.% soft segment content were synthesized using poly(epsilon-caprolactone)diol, 4,4'-diphenylmethane diisocyanate, 1,4-butanediol and/or N,N-bis(2-hydroxyethyl)-isonicotinamide. To introduce substrate bonding antibacterial activity, pyridinium was prepared through a neutralization reaction using 1-iodooctane as neutralization agent. For the SMPU ionomer film obtained, tensile testing at 70 degrees C and dynamic mechanical analysis suggests that, at temperatures>T(ms) (the melting point of soft segments), 6.72 and 29.55 mol.% pyridinium within hard segments significantly decreased the mechanical properties such as the stress at 100% elongation (70 degrees C), the initial modulus (70 degrees C) and the elastic modulus (75-110 degrees C). Cyclic tensile investigation demonstrated that the two factors, soft segment crystallization and hard segment physical crosslink, play a very important role in shape memory function in SMPU ionomers. For the each individual specimen, the fixity ratio increased, and the recovery ratio decreased with the extension of cooling time. After sufficient cooling time, the fixity ratio of all specimens can reach a high value (approximately 95%). Owing to the disrupted physical crosslink in the sample containing 29.55 mol.% pyridinium, the crystallization rate of soft segments has less effect on shape fixity. Therefore, a high fixity ratio (93.8%) can be achieved in a short cooling time (30 s). In the control sample, the fixity ratio is only 73.7% after 30 s cooling. In addition, the admirable substrate bonding antibacterial activity of prepared SMPU ionomers was verified using standards AACTT 147 and ASTM E2149 in comparison with the control sample. The antibacterial activity of SMPU ionomers on Gram-positive bacteria (Staphylococcus aureus) is significant, and the rate of reduction of bacteria is 100%; the antibacterial activity on Gram-negative bacteria (Klebsiella pneumoniae) increases from 83.6% to 90.7% with increase in pyridinium content from 6.72 to 29.55 mol.%.

Risk behaviours in HIV-positive men who have sex with men participating in an intervention in a primary care setting

Men who have sex with men receiving HIV care reported their sexual behaviours and their intentions, classified according to the Transtheoretical Model of Change, to modify the following behaviours: (1) condom use by partner type and activity type; (2) reduction of partner number; and (3) disclosure of HIV serostatus to partners. Most participants were white (68.8%) or black (29.5%) and were more likely to report unprotected sex with HIV-positive than with serodiscordant partners for most activities. Whites reported more partners than black patients (mean 4.1 versus 2; P < 0.0001) and black participants reported fewer HIV-negative (P = 0.0084) and -unknown status partners (P = 0.00095) than whites. Cocaine/crack use was associated with more sexual partners (P = 0.001) and more frequent unprotected sex with HIV-negative or -unknown status partners (P = 0.036). Readiness to change risk behaviour varied by partner status and type of sexual activity. Understanding patients' risks and their readiness to change behaviours may help providers to promote sexual health.

Regional hypoxia correlates with the uptake of a radiolabeled targeted marker of angiogenesis in rat model of myocardial hypertrophy and ischemic injury

BACKGROUND

Non-invasive imaging strategies play a critical role for assessment of the efficacy of angiogenesis therapies. Hypoxia resulting from deficient blood flow is a potent stimulator of angiogenesis which is marked by upregulated alphavbeta3 integrin receptor.

METHODS AND RESULTS

The use of dual-isotope radiotracers targeted at alphavbeta3 and myocardial hypoxia has been demonstrated to non-invasively track hypoxia-induced angiogenesis in ischemic rat model of myocardial hypertrophy, which was induced by non-occlusive abdominal aortic banding followed by myocardial infarction at 6 weeks after the banding procedure. The pressure overload-induced myocardial hypertrophy was confirmed by 2D echocardiography. Two radiotracers; 111In-labeled agent targeted at the alphavbeta3 (RP748) and 99mTc-labeled nitroimidazole retained in hypoxic myocardium (BRU-5921) have been used. Gamma well counting analysis demonstrated an inverse linear relationship (R2=0.5) between BRU-5921 myocardial uptake and the degree of hypoperfusion assessed by 201Tl chloride. 111In-RP748 was found to be preferentially retained in hypoxic myocardium identified by increased BRU-5921 uptake and localized to anterior-lateral wall as assessed by dual-isotope microautoradiography. There was a significant (P<0.01) almost four-fold increase in RP748 uptake in myocardial segments with highest relative BRU-5921 retention (200-600% non-ischemic). Immunohistochemical staining confirmed that increased RP748 uptake is associated with an augmented alphav and beta3 integrin expression within infarcted myocardium.

CONCLUSIONS

Angiogenesis in the rodent model of combined myocardial hypertrophy and infarction was successfully assessed with alphavbeta3-targeted agent in relation to tissue hypoxia measured with 99mTc -labeled nitroimidazole retained in hypoxic myocardium. Regional retention of RP748 correlated well with BRU-5921 retention, supporting the role of RP748 as a targeted marker of hypoxia-stimulated angiogenesis with a potential clinical use to track naturally occurring and therapeutic angiogenesis and to predict the left ventricular remodeling in patients following myocardial infarction.

Poly-GLP-1, a novel long-lasting glucagon-like peptide-1 polymer, ameliorates hyperglycaemia by improving insulin sensitivity and increasing pancreatic beta-cell proliferation

AIM

The clinical value of glucagon-like peptide-1 (GLP-1) is restricted because of its short half-life. To overcome this limitation, a new polymer of GLP-1 was developed by prodrug strategy, termed Poly-GLP-1, and its pharmacological properties were investigated.

METHODS

The in vitro release kinetics of GLP-1 from Poly-GLP-1 was analysed by Western blot. Plasma GLP-1 levels following a single administration of Poly-GLP-1 were determined by enzyme-linked immunosorbent assay. The in vitro effects of Poly-GLP-1 were evaluated using isolated pancreatic islets. The acute effects on glycaemic control and food intake were investigated in C57BL/6J mice s.c. administered with Poly-GLP-1. The chronic effects of Poly-GLP-1 on glycaemic control were further assessed in C57BL/6J and db/db mice treated twice daily for 6 weeks.

RESULTS

Pro-GLP-1 dose dependently increased insulin secretion and decreased glucose, but did not exhibit the insulinotropic action in isolated pancreatic islets without plasma. The glucose-lowering actions of Poly-GLP-1 (3 nmol/kg) remained no less than 12 h after a single injection. Poly-GLP-1 caused a durable restoration of glycaemic control, food intake and body weight gain in db/db mice following 6-week administration. The chronic treatment with Poly-GLP-1 improved glucose tolerance and insulin sensitivity and increased beta-cell mass and proliferation in db/db mice. There was little effect on normal mice treated in the same manner.

CONCLUSIONS

Our results indicated that Poly-GLP-1, a novel GLP-1 polymer, has long-lasting and potent effects on glycaemic control in vivo, and these beneficial effects may be because of improvement of insulin sensitivity and promotion of islet growth and function.

Tolerant T cells inhibit natural killer cells function in antigen-presenting cells in an independent fashion

Understanding the relationships among immune cells in the setting of immunologic tolerance is imperative to maintain organ and tissue transplants. T cells and natural killer (NK) cells are responsible for both immune tolerance and immune rejection; however, there is only limited knowledge about the relevance of T and NK cells in tolerance. To address this issue, we explored the possible actions of tolerant T cells on NK cells by the means of mixed lymphocyte co-cultures and NK cytotoxicity assays. We showed that tolerant T cell-induced blockade of the co-stimulatory pathway significantly inhibited NK cell function in vitro regarding antigen-presenting cells. This action was cell-cell-contact dependent. We argue that tolerant T cells and NK cells impart synergistic cooperation to maintain transplant tolerance.