Detection of cytotoxic activity of lectin on human colon adenocarcinoma (Sw480) and epithelial cervical carcinoma (C33-A)

Lectins comprise a heterogeneous class of proteins that recognize the carbohydrate moieties of glycoconjugates with high specificity. Numerous studies have shown that lectins are capable of recognizing specific carbohydrate moieties displayed by malignant cells or tissues. The present work was performed to investigate the effects of tepary bean (Phaseolus acutifolius) lectins on proliferation, colony formation, and alteration of DNA synthesis of human malignant cells. Tepary bean lectin showed dose dependent  effects on the inhibition of viability as well as on colony formation in two human malignant cells lines (C33-A, Sw480); By contrast, tepary bean lectin only showed significant effects on DNA synthesis on Sw480 cells. Our results provide evidence of the anti- proliferative and cytotoxic effects of the tepary bean lectins on C33-A and Sw480 cells lines.

The efficacy of NP11-4-derived immunotoxin scFv-artesunate in reducing hepatic fibrosis induced by Schistosoma japonicum in mice

Schistosomiasis is one of the most prevalent parasitic diseases in China, and hepatic fibrosis caused by schistosome infection is the principal cause of death. The aim of this study was to evaluate the efficacy of NP11-4-derived immunotoxin scFv-artesunate on Schistosoma japonicum-induced hepatic fibrosis. A single-chain variable fragment (scFv) was generated from the murine anti-Schistosoma japonicum (S. japanicum) monoclonal antibody NP11-4. The scFv was expressed as a soluble protein and purified by Ni-affinity chromatography. After conjugation with artesunate, the binding ability with soluble egg antigens (SEA) was determined by an enzyme-linked immunosorbent assay (ELISA). The biological activity of purified scFv, scFv-artesunate (immunotoxin), and artesunate was detected in vivo. Image-Pro Plus software was used to analyze the size of egg granuloma and the extent of liver fibrosis. The recombinant scFv expession vector was constructed and expressed successfully. After purification by a His-trap Ni-affinity column, the scFv yield was approximately 0.8 mg/L of culture medium. ELISA results showed that chemical conjugation did not affect the binding activity of the immunotoxin. Our animal experiments indicated that the immunotoxin could significantly reduce the size of egg granuloma in the liver and inhibit hepatic fibrosis. The immunotoxin could be used as a promising candidate in the targeted therapy of S. japonicum-induced hepatic fibrosis.

Current status of Barrett's esophagus research in Asia

In Western countries, the epidemiology of esophageal cancer has changed considerably over the past decades with a rise in the ratio of adenocarcinoma to squamous cell carcinoma. Although the prevalence of gastroesophageal reflux is increasing in Asia, the prevalences of Barrett's esophagus (BE) and esophageal adenocarcinoma (EAC) have remained low in most Asian countries. The Asian Barrett's Consortium recently conducted a review of published studies on BE from Asia to assess the current status of BE research in Asia, and to recommend potential areas for future BE research in the region. Differences in study design, enrolled population, and endoscopic biopsy protocols used have led to substantial variability in the reported BE prevalence (0.06% to 19.9%) across Asia. In particular, some Japanese studies used diagnostic criteria that differed considerably from what was used in most Asian studies. As in Western countries, increased age, male sex, tobacco smoking, reflux symptoms, and erosive esophagitis have been found to be risk factors for BE in several case-control studies from Asia. The Prague C and M criteria, developed to provide better interobserver reliability in diagnosis and grading of BE, are currently under extensive evaluation in the Asian population. There is a need for standardized protocols for endoscopic and histopathologic diagnosis before initiating collaborative projects to identify etiologic determinants of BE and its ensuing malignant transformation. At present, data regarding the management and long-term outcome of BE are extremely limited in Asia. More studies of BE in this geographic area are warranted.

Rapid improvement of chronic stroke deficits after perispinal etanercept: three consecutive cases

BACKGROUND

Thrombolytic therapy reduces stroke size and disability by reperfusion and salvage of ischaemic penumbra. Emerging evidence suggests that retrieved penumbra may be the site of ongoing inflammatory pathology that includes extensive microglial activation. Microglial activation may be associated with excessive levels of tumour necrosis factor (TNF) and resultant neurotoxicity. Etanercept, a potent biologic TNF antagonist, reduces microglial activation in experimental models and has been therapeutically effective in models of brain and neuronal injury. Perispinal administration of etanercept, previously reported to be beneficial for the treatment of Alzheimer's disease, may facilitate delivery of etanercept into the brain.

OBJECTIVE

The objective of this report is to document the initial clinical response to perispinal etanercept in the first chronic stroke cohort so treated.

METHODS

Three consecutive patients with stable and persistent chronic neurological deficits due to strokes that had failed to resolve despite previous treatment and rehabilitation were evaluated at an outpatient clinic. They were treated off-label with perispinal etanercept as part of the clinic's practice of medicine.

RESULTS

All three patients had chronic hemiparesis, in addition to other stroke deficits. Their stroke distributions were right middle cerebral artery (MCA), brainstem (medulla) and left MCA. The two patients with MCA strokes had both received acute thrombolytic therapy. Each of the three patients was treated with an initial dose of perispinal etanercept 13, 35 and 36 months following their acute stroke, respectively. Significant clinical improvement following perispinal etanercept administration was observed in all patients. Onset of clinical response was evident within 10 minutes of perispinal injection in all patients. Improvements in hemiparesis, gait, hand function, hemi-sensory deficits, spatial perception, speech, cognition and behaviour were noted among the patients treated. Each patient received a second perispinal etanercept dose at 22-26 days after the first dose that was followed by additional clinical improvement.

CONCLUSIONS

Open-label administration of perispinal etanercept resulted in rapid neurological improvement in three consecutive patients with chronic neurological dysfunction due to strokes occurring 13-36 months earlier. These results suggest that stroke may result in chronic TNF-mediated pathophysiology that may be amenable to therapeutic intervention long after the acute event. Randomized clinical trials of perispinal etanercept for selected patients with chronic neurological dysfunction following stroke are indicated.

Antisense oligonucleotide inhibits avian influenza virus H5N1 replication by single chain antibody delivery system

H5N1 avian influenza virus (AIV) causes widespread infections in poultry and wild birds, and has the potential to emerge as a pandemic threat to human. Antisense oligonucleotides (AS ODNs) are highly effective at inhibiting gene replication. Antibody-mediated delivery is a novel approach to target specific cells and tissues. In this study, we designed and synthesized three AS ODNs (PA4, PA492 and PA1203) specific for conserved region of AIV PA protein, and all the three AS ODNs could inhibit viral replication. The PA492 ODN showed the best antiviral effect by viral titers and quantitative RT-PCR in MDCK cells. The fusion protein scFv-tP was constructed as a single chain variable fragment (scFv) against AIV hemaglutinin antigen with a truncated protamine (tP). The results showed that scFv-tP fusion improved the antiviral effectiveness of PA492 in MDCK cells as measured by viral titers, quantitative RT-PCR and indirect immunofluorescence (IFA) assays. In addition, scFv-tP-delivered PA492 was also found to partially protect mice from lethal H5N1 influenza virus challenge. Using scFv-tP delivery, fluorescein isothiocyanate labeled-PA492 was found to be significantly localized in the lungs, compared to liposome-delivered PA492. Moreover, the fusion protein mediated PA492 had a lower lung index and viral titers in the infected mice as compared with the liposome method. These results provided a potential method for using anti-HA fusion protein for the targeted delivery of AS ODNs against AIV H5N1.

Calpain 2 controls turnover of LFA-1 adhesions on migrating T lymphocytes

The immune cells named T lymphocytes circulate around the body fulfilling their role in immunosurveillance by monitoring the tissues for injury or infection. To migrate from the blood into the tissues, they make use of the integrin LFA-1 which is exclusively expressed by immune cells. These highly motile cells attach and migrate on substrates expressing the LFA-1 ligand ICAM-1. The molecular events signaling LFA-1 activation and adhesion are now reasonably well identified, but the process of detaching LFA-1 adhesions is less understood. The cysteine protease calpain is involved in turnover of integrin-mediated adhesions in less motile cell types. In this study we have explored the involvement of calpain in turnover of LFA-1-mediated adhesions of T lymphocytes. Using live cell imaging and immunohistochemistry, we demonstrate that turnover of adhesions depends on the Ca2+-dependent enzyme, calpain 2. Inhibition of calpain activity by means of siRNA silencing or pharmacological inhibition results in inefficient disassembly of LFA-1 adhesions causing T lymphocyte elongation and shedding of LFA-1 clusters behind the migrating T lymphocytes. We show that calpain 2 is distributed throughout the T lymphocyte, but is most active at the trailing edge as detected by expression of its fluorescent substrate CMAC,t-BOC-Leu-Met. Extracellular Ca2+ entry is essential for the activity of calpain 2 that is constantly maintained as the T lymphocytes migrate. Use of T cells from a patient with mutation in ORAI1 revealed that the major calcium-release-activated-calcium channel is not the ion channel delivering the Ca2+. We propose a model whereby Ca2+ influx, potentially through stretch activated channels, is sufficient to activate calpain 2 at the trailing edge of a migrating T cell and this activity is essential for the turnover of LFA-1 adhesions.

Anticancer properties of 10-hydroxycamptothecin in a murine melanoma pulmonary metastasis model in vitro and in vivo

Lung cancer, including lung metastatic cancer, remains one of the most difficult types of cancer to treat. Therefore, the search for new agents for its treatment is very important. 10-Hydroxycamptothecin (HCPT) was proved to have ideal anticancer activity in curing series cancer cells. In this study, the anticancer effect of HCPT on melanoma lung metastasis cancer was investigated by several administration routes, and whether the effect may be attributed to the induction of tumor cells apoptosis was determined. MTT assay results showed that HCPT exhibited selective cytotoxic activity against B16-F10 cells in a concentration- and time-dependent manner. Hoechst 33258 staining and transmission electron microscopy showed typical apoptotic morphology such as condensed chromatin, irregular nuclei, and apoptotic body formation. Flow cytometry analysis indicated a growth on apoptotic cells and a cell-cycle arrest in S phase after treatment with HCPT. In vivo melanoma pulmonary metastases were inhibited by treatment with HCPT. A more significant inhibition was observed if HCPT was administered by aerosol inhalation than that given by i.v. or i.p. administration. Thus, HCPT exhibited potential anticancer activity against B16-F10 cells in vitro and in vivo. However, the possible mechanisms involved still need to be investigated to explain this behavior.

[The role of adipokines and insulin resistance in the pathogenesis of nonalcoholic fatty liver disease]

Nonalcoholic fatty liver disease (NAFLD) develops in 17-33% of the population of developed countries. The incidence of NAFLD is constantly growing due to the increasing prevalence of obesity. It is estimated that one third of subjects with NAFLD suffer from nonalcoholic steatohepatitis (NASH) and 15% of them develop liver cirrhosis within a five-year period. In recent years this important complication of obesity became the subject of numerous studies. It, the pathogenesis of NAFLD is still unclear. A key role in the development of this disease was attributed to insulin resistance. Hormones and cytokines produced by adipose tissue called adipokines may be a link between obesity, insulin resistance, and NAFLD. However, it is well known that increased levels of adipokines such as TNF-alpha, IL-6, and resistin and a decreased level of adiponectin augment inflammation in the liver. Further studies are necessary to explain the roles of leptin, visfatin, retinol binding protein-4, omentin, and vaspin in the pathogenesis of NAFLD. The aim this paper is to introduce new areas of study on the pathogenesis of NAFLD.

HAX-1: a multifaceted antiapoptotic protein localizing in the mitochondria and the sarcoplasmic reticulum of striated muscle cells

HAX-1 comprises a family of ubiquitously expressed proteins with antiapoptotic properties. In the current study, we investigated HAX-1's temporospatial distribution in rat striated muscles during development and in adulthood. In cardiocytes, HAX-1 is organized at the level of Z-disks throughout embryogenesis and adulthood; however, in skeletal myofibers, it is in register with M-bands during embryonic and early postnatal life and Z-disks during late postnatal and adult life. Immunoelectron microscopy and subcellular fractionation demonstrated that HAX-1 proteins localize at the mitochondrial and sarcoplasmic reticulum (SR) membranes, as well as at sites where the two are closely apposed. Variants I and II selectively concentrate in the mitochondrial membranes, whereas variants III, IV, and V localize in both organelles, albeit to varying extents. Deletion analysis combined with cellular transfections indicated that elimination of HAX-1's NH(2)-terminus abolishes its mitochondrial targeting and attenuates its antiapoptotic capacity, while removal of its binding site for the SR protein phospholamban (PLN) prevents its translocation to the SR. Consistent with this, HAX-1 is preferentially lost from the SR of PLN-deficient hearts. Our findings are the first to present a comprehensive characterization of HAX-1's expression in striated muscles and to provide insights on the mechanisms through which it may modulate apoptosis.

Hepatitis C virus core protein and cellular protein HAX-1 promote 5-fluorouracil-mediated hepatocyte growth inhibition

Hepatitis C virus (HCV) often causes chronic infection and may lead to hepatocellular carcinoma (HCC). We have shown previously that HCV core protein has pleiotropic functions, including transcriptional regulation of a number of cellular genes, although the mechanism for gene regulation remains unclear. In this study, a mammalian two-hybrid screen identified a novel binding partner, HS1-associated protein X-1 (HAX-1), for HCV core protein from a human liver cDNA library. An association between HAX-1 and HCV core protein was further verified by confocal microscopy and coimmunoprecipitation in HepG2 cells expressing HCV core or full-length (FL) gene. Both HCV core protein and a chemotherapeutic agent for HCC, 5-flouorouracil (5-FU), are known to modulate p53. We examined here whether an association between core and HAX-1 has any functional relevance to p53 modulation in 5-FU-treated cells. For this, the role of HAX-1 on 5-FU treatment was examined in HepG2 cells expressing HCV core or FL gene using cell proliferation, p53 expression, and caspase activation analysis. Cells expressing HCV-core or FL gene were more susceptible to 5-FU-induced growth inhibition than control cells, whereas cell survival was enhanced after suppression of HAX-1 by small interfering RNA. Further, 5-FU-mediated p53 expression was reduced with concurrent HAX-1 suppression in core- or polyprotein-expressing cells compared to control HepG2 cells, and caspase-2 and -7 activities were diminished. On the other hand, HCV core protein did not play a detectable role in 5-FU-mediated caspase-7 activation in the absence of functional p53 in Hep3B or Huh-7 cells. These observations underscore an association between HCV core and HAX-1, which promotes 5-FU mediated p53-dependent caspase-7 activation and hepatocyte growth inhibition.

HAX-1: a multifunctional protein with emerging roles in human disease

HS-1-associated protein X-1 (HAX-1) was identified more than 10 years ago as a novel protein with ubiquitous tissue expression and a predominantly mitochondrial localization at the subcellular level. Recent studies have shown that homozygous mutations in the HAX1 gene are associated with autosomal recessive forms of severe congenital neutropenia (also known as Kostmann disease), and results from studies in mice and men are beginning to unravel a prominent role for HAX-1 in apoptosis signaling not only in the hematopoietic compartment, but also in the central nervous system. Moreover, several different cellular and viral binding partners of HAX-1 have been identified thus pointing toward a complex and multifunctional role of this protein. HAX-1 has also been shown to bind to the 3' untranslated regions of certain mRNAs and could therefore contribute to the regulation of transport and/or stability of such transcripts. The present review discusses the emerging and divergent roles of HAX-1, including its involvement in cell migration, apoptosis signaling, and mRNA surveillance. The importance of HAX-1 in human disease is also highlighted and outstanding questions that remain to be addressed are identified.

Duodenal Carbonic Anhydrase: Mucosal Protection, Luminal Chemosensing, and Gastric Acid Disposal

The duodenum serves as a buffer zone between the stomach and jejunum. Over a length of only 25 cm, large volumes of strong acid secreted by the stomach must be converted to the neutral-alkaline chyme of the hindgut lumen, generating large volumes of CO2, which the duodenum then absorbs. The duodenal mucosa consists of epithelial cells connected by low-resistance tight junctions, forming a leaky epithelial barrier. Despite this high permeability, the epithelial cells, under intense stress from luminal mineral acid and highly elevated P(CO2), maintain normal functioning. Furthermore, the duodenum plays an active role in foregut acid-base homeostasis, absorbing large amounts of H+ and CO2 that are recycled by the gastric parietal cells. Prompted by the high expression of cytosolic and membrane carbonic anhydrase (CAs) in duodenal epithelial cells, and the intriguing observation that CA activity appears to augment cellular acid stress, we formulated a novel hypothesis regarding the role of CA in duodenal acid absorption, epithelial protection, and chemosensing. In this review, we will describe how luminal CO2/H+ traverses the duodenal epithelial cell brush border membrane, acidifies the cytoplasm, and is sensed in the subepithelium.

Extracellular calcium acts as a "third messenger" to regulate enzyme and alkaline secretion

It is generally assumed that the functional consequences of stimulation with Ca²⁺-mobilizing agonists are derived exclusively from the second messenger action of intracellular Ca²⁺, acting on targets inside the cells. However, during Ca²⁺ signaling events, Ca²⁺ moves in and out of the cell, causing changes not only in intracellular Ca²⁺, but also in local extracellular Ca²⁺. The fact that numerous cell types possess an extracellular Ca²⁺ “sensor” raises the question of whether these dynamic changes in external [Ca²⁺] may serve some sort of messenger function. We found that in intact gastric mucosa, the changes in extracellular [Ca²⁺] secondary to carbachol-induced increases in intracellular [Ca²⁺] were sufficient and necessary to elicit alkaline secretion and pepsinogen secretion, independent of intracellular [Ca²⁺] changes. These findings suggest that extracellular Ca²⁺ can act as a “third messenger” via Ca²⁺ sensor(s) to regulate specific subsets of tissue function previously assumed to be under the direct control of intracellular Ca²⁺.

Asymmetrical, agonist-induced fluctuations in local extracellular [Ca(2+)] in intact polarized epithelia

We recently proposed that extracellular Ca(2+) ions participate in a novel form of intercellular communication involving the extracellular Ca(2+)-sensing receptor (CaR). Here, using Ca(2+)-selective microelectrodes, we directly measured the profile of agonist-induced [Ca(2+)]ext changes in restricted domains near the basolateral or luminal membranes of polarized gastric acid-secreting cells. The Ca(2+)-mobilizing agonist carbachol elicited a transient, La(3+)-sensitive decrease in basolateral [Ca(2+)] (average approximately 250 microM, but as large as 530 microM). Conversely, carbachol evoked an HgCl2-sensitive increase in [Ca(2+)] (average approximately 400 microM, but as large as 520 microM) in the lumen of single gastric glands. Both responses were significantly reduced by pre-treatment with sarco-endoplasmic reticulum Ca(2+) ATPase (SERCA) pump inhibitors or with the intracellular Ca(2+) chelator BAPTA-AM. Immunofluorescence experiments demonstrated an asymmetric localization of plasma membrane Ca(2+) ATPase (PMCA), which appeared to be partially co-localized with CaR and the gastric H(+)/K(+)-ATPase in the apical membrane of the acid-secreting cells. Our data indicate that agonist stimulation results in local fluctuations in [Ca(2+)]ext that would be sufficient to modulate the activity of the CaR on neighboring cells.

Effects of feeding on metabolism, gas transport, and acid-base balance in the bullfrog Rana catesbeiana

Massive feeding in ectothermic vertebrates causes changes in metabolism and acid-base and respiratory parameters. Most investigations have focused on only one aspect of these complex changes, and different species have been used, making comparison among studies difficult. The purpose of the present study was, therefore, to provide an integrative study of the multiple physiological changes taking place after feeding. Bullfrogs (Rana catesbeiana) partly submerged in water were fed meals (mice or rats) amounting to approximately (1)/(10) of their body weight. Oxygen consumption increased and peaked at a value three times the predigestive level 72-96 h after feeding. Arterial PO(2) decreased slightly during digestion, whereas hemoglobin-bound oxygen saturation was unaffected. Yet, arterial blood oxygen content was pronouncedly elevated because of a 60% increase in hematocrit, which appeared mediated via release of red blood cells from the spleen. Gastric acid secretion was associated with a 60% increase in plasma HCO3(-) concentration ([HCO3(-)]) 48 h after feeding. Arterial pH only increased from 7.86 to 7.94, because the metabolic alkalosis was countered by an increase in PCO(2) from 10.8 to 13.7 mm Hg. Feeding also induced a small intracellular alkalosis in the sartorius muscle. Arterial pH and HCO3(-) returned to control values 96-120 h after feeding. There was no sign of anaerobic energy production during digestion as plasma and tissue lactate levels remained low and intracellular ATP concentration stayed high. However, phosphocreatine was reduced in the sartorius muscle and ventricle 48 h after feeding.

The gastric mucosal barrier and ulceration

The gastric mucosal barrier is that property which defends against acid and which impedes diffusion of acid from the lumen into the mucosa. The disappearance of luminal H+ is linearly related to luminal (H+) both in the normal stomach and in stomachs exposed to barrier breakers. The latter invaribaly produce anatomic evidence of surface cellular injury. Strong direct evidence for back diffusion of luminal H+ derives from the recent demonstration of a highly significant correlation between the disappearance of luminal H+ and the pH of the lamina propria measured by an implanted microelectrode. The permeabilities of the antrum and fundus to H+ differ from each other in the same species and in different species. Gastric ulceration does not occur in the absence of luminal acid and is not dependent upon the absolute loss of H+ from the luminal solution. Mucosal ischemia induced by hemorrhage reduces tolerance against ulceration as does inhibition of acid secretion, acidification of the tissue caused by absence of nutrient bicarbonate, inhibition of carbonic anhydrase, and blockade of anion exchange by SITS. A tentative schema is proposed by which defense against luminal acid is accomplished in gastric mucosa.

Effect of Krebs cycle intermediates and inhibitors on toad gastric mucosa

An attempt to increase the permeability of gastric mucosa to exogenous Krebs cycle intermediates seemed advisable for a better understanding their relationship with acid secretion. At pH 7.4, citrate, oxoglutarate, fumarate, and malate had no significant effect on oxygen uptake (QO2) nor on acid secretion (QH+) by toad gastric mucosa; succinate increased QO2 slightly and had no effect on QH+; but at pH 5.0, oxoglutarate and succinate increased QO2 by 18 and 21%, respectively. 14CO2 evolved by gastric mucosa incubated with [14C]oxoglutarate, succinate, malate, or citrate was 155, 92, 128, and 353%, respectively, greater at pH 5. Citrate, oxoglutarate, succinate, fumarate, and malate increased QH+ by theophylline-stimulated mucosa at pH 5.0 by 25, 39, 35, 17 and 28%, respectively. Oxoglutarate-dependent respiration was shown to correlate with oxoglutarate oxidation. Malonate and arsenite inhibited QO2 and QH+; malonate inhibition was reversed by washout or by succinate. Arsenite was reversed by washout and accelerated by addition of lipoate immediately after washout. The results suggest that the Krebs cycle has concomitant roles in the regulation of QH+ and oxidative metabolism in the toad gastric mucosa.