Vacuolar ATPase 'a2' isoform exhibits distinct cell surface accumulation and modulates matrix metalloproteinase activity in ovarian cancer

Tumor associated vacuolar H+-ATPases (V-ATPases) are multi-subunit proton pumps that acidify tumor microenvironment, thereby promoting tumor invasion. Subunit ‘a’ of its V0 domain is the major pH sensing unit that additionally controls sub-cellular targeting of V-ATPase and exists in four different isoforms. Our study reports an elevated expression of the V-ATPase-V0a2 isoform in ovarian cancer(OVCA) tissues and cell lines(A2780, SKOV-3 and TOV-112D). Among all V0’a’ isoforms, V0a2 exhibited abundant expression on OVCA cell surface while normal ovarian epithelia did not. Sub-cellular distribution of V-ATPase-V0a2 confirmed its localization on plasma-membrane, where it was also co-associated with cortactin, an F-actin stabilizing protein at leading edges of cancer cells. Additionally, V0a2 was also localized in early and late endosomal compartments that are sites for modulations of several signaling pathways in cancer. Targeted inhibition of V-ATPase-V0a2 suppressed matrix metalloproteinase activity(MMP-9 & MMP-2) in OVCA cells. In conclusion, V-ATPase-V0a2 isoform is abundantly expressed on ovarian tumor cell surface in association with invasion assembly related proteins and plays critical role in tumor invasion by modulating the activity of matrix-degrading proteases. This study highlights for the first time, the importance of V-ATPase-V0a2 isoform as a distinct biomarker and possible therapeutic target for treatment of ovarian carcinoma.

Natural history of asymptomatic gallstones: differential behaviour in male and female subjects

OBJECTIVE

The natural history of asymptomatic (silent) gallstones has been inadequately studied. Existing information derives from studies based on oral cholecystography or relatively small sample sizes. We planned a retrospective cohort study in subjects with gallstones to determine conversion rates from asymptomatic to symptomatic.

METHODS

We extracted data from computerised databases of one government hospital and two private clinics in Malaysia. Files were scrutinised to ensure that criteria for asymptomatic gallstones were fulfilled. Patients were called on telephone, further questioned to confirm that the gallstones at detection were truly asymptomatic, and asked about symptoms that were consistent with previously defined criteria for biliary colic. Appropriate ethical clearances were taken.

RESULTS

213 (112 males) patients fulfilled the criteria for asymptomatic gallstones and could be contacted. 23 (10.8%) developed pain after an average follow up interval of 4.02 years (range 0.1-11 years). Conversion rates from asymptomatic to symptomatic gallstones were high in the first two years of follow up, averaging 4.03±0.965 per year. Over time the conversion rates slowed, and by year 10 the annual conversion rate averaged only 1.38±0.29. Conversion rates were much higher for females compared to males (F:M hazard ratio 3.23, SE 1.54, p>z 0.014). The lifetime risks for conversion approached 6.15% for males, and 22.1% for females.

CONCLUSION

In conclusion, asymptomatic gallstones are much more likely to convert to symptomatic in females than in males. Males in whom asymptomatic stones are discovered should be advised conservative treatment. Surgery may be preferable to conservative management if the subject is a young female.

Bioactivity studies and adhesion of human osteoblast (hFOB) on silicon-biphasic calcium phosphate material

Surface reactivity of bioactive ceramics contributes in accelerating bone healing by anchoring osteoblast cells and the connection of the surrounding bone tissues. The presence of silicon (Si) in many biocompatible and bioactive materials has been shown to improve osteoblast cell adhesion, proliferation and bone regeneration due to its role in the mineralisation process around implants. In this study, the effects of Si-biphasic calcium phosphate (Si-BCP) on bioactivity and adhesion of human osteoblast (hFOB) as an in vitro model have been investigated. Si-BCP was synthesised using calcium hydroxide (Ca(OH)₂) and phosphoric acid (H₃PO₄) via wet synthesis technique at Ca/P ratio 1.60 of material precursors. SiO₂ at 3 wt% based on total precursors was added into apatite slurry before proceeding with the spray drying process. Apatite powder derived from the spray drying process was pressed into discs with Ø 10 mm. Finally, the discs were sintered at atmospheric condition to obtain biphasic hydroxyapatite (HA) and tricalcium phosphate (TCP) peaks simultaneously and examined by XRD, AFM and SEM for its bioactivity evaluation. In vitro cell viability of L929 fibroblast and adhesion of hFOB cell were investigated via AlamarBlue® (AB) assay and SEM respectively. All results were compared with BCP without Si substitution. Results showed that the presence of Si affected the material’s surface and morphology, cell proliferation and cell adhesion. AFM and SEM of Si-BCP revealed a rougher surface compared to BCP. Bioactivity in simulated body fluid (SBF) was characterised by pH, weight gain and apatite mineralisation on the sample surface whereby the changes in surface morphology were evaluated using SEM. Immersion in SBF up to 21 days indicated significant changes in pH, weight gain and apatite formation. Cell viability has demonstrated no cytotoxic effect and denoted that Si-BCP promoted good initial cell adhesion and proliferation. These results suggest that Si-BCP’s surface roughness (164 nm) was significantly higher than BCP (88 nm), thus enhancing the adhesion and proliferation of the osteoblast.

Tetrabutylammonium methacrylate as a novel receptor for selective extraction of sulphonylurea drugs from biological fluids using molecular imprinting

Glibenclamide (GLIB), an oral antidiabetic medication of the sulphonylurea drug family, was stoichiometrically imprinted using tetrabutylammonium methacrylate as the functional monomer, for the first time in molecular imprinting, and utilising the sulphonylurea affinity for carboxylate anions. Solution association between the drug and the novel functional monomer was studied by ¹H-NMR titrations, whereby evidence of sulphonylurea deprotonation followed by the formation of "narcissistic" GLIB dimers was found when tested in CDCl₃, while an affinity constant in excess of 10⁵ L mol^-1 was measured in DMSO-d₆. Detailed analysis of GLIB binding on the subsequently prepared imprinted and non-imprinted polymers confirmed the deactivation of binding sites by exchange of a proton between GLIB and methacrylate, followed by extraction of the tetrabutylammonium counterion from the polymer matrix, resulting in overall reduced binding capacities and affinities by the imprinted material under equilibrium conditions. An optimised MI-SPE protocol, which included a binding site re-activation step, was developed for the extraction of GLIB from blood serum, whereby recoveries of up to 92.4% were obtained with an exceptional sample cleanup.

MicroRNA-regulated molecular mechanism underlying bovine subclinical endometritis

An impaired uterine environment triggered by the incidence of subclinical endometritis often compromises fertility in the bovine. The uterus is a dynamic organ with tight regulation of specific genes at the transcriptional and translational levels. Herein, we hypothesised that subclinical endometritis alters the expression of uterine microRNAs (miRNAs), which may result in the dysregulation of corresponding target genes and biological pathways. To test this hypothesis, we used a genome-wide RT(2) (Exiqon, Vedbaek, Denmark) miRNA PCR array consisting of 354 miRNA primers and analysed miRNA expression in uterine cytobrush samples taken from cows with and without subclinical endometritis. The results revealed aberrant expression of 23 miRNAs in cows with subclinical endometritis compared with healthy cows. Furthermore, we designed an in vitro endometrial cell culture model challenged by lipopolysaccharide (LPS) to validate the differential regulation of miRNAs in cytobrush samples. Interestingly, we observed similar expression miRNA patterns in cytobrush samples taken from cows with or without subclinical endometritis and in vitro cultured endometrial cells challenged by LPS. To trace signalling pathways and biological functions potentially controlled by the aberrantly expressed miRNAs, we filtered high-ranking target genes from miRBase and analysed them using ingenuity pathway analysis. The gene networks, canonical pathways and biological functions strikingly converged to signalling pathways that mediate inflammatory responses, cellular proliferation, cell movement, the cell cycle and apoptosis in the bovine endometrium. In addition, expression analysis of key genes from the gene networks confirmed their presence and the potential regulation of these genes by uterine miRNAs. Furthermore, luciferase assay data substantiated the primary information from bioinformatic prediction that generated potential target genes for the dysregulated miRNAs in subclinical endometritis. Together, these data suggest the potential regulatory role of uterine miRNAs in the development and progression of bovine subclinical endometritis.

Abstract 4939: The baffling effect of bafilomycin on Notch signaling in triple-negative breast cancer

Triple Negative Breast Cancers (TNBC) constitute 15 to 20% of all breast cancers and lack expression of ER/PR and Her2 receptors. Owing to an aggressive phenotype and lack of targeted therapies, TNBC has poor prognosis. Notch signaling is an evolutionarily conserved signaling pathway known to be important for normal mammary development and breast cancer progression. Although there has been considerable research on the role of Notch in TNBC, little is known about its regulation. Identifying novel molecules that regulate Notch can lead to the development of effective combinatorial treatments. The Vacuolar ATPase (V-ATPase) is a proton pump responsible for maintaining pH. Expression of V-ATPase is upregulated in tumor cells, promoting cancer proliferation and metastasis. We have previously identified the role of V-ATPase a2 isoform (V0a2) in pregnancy and cancer. Here, we report that V-ATPase regulates Notch Signaling in TNBC. Upon treatment with Bafilomycin A1 (BafA1), a specific V-ATPase inhibitor, Notch and Wnt Signaling genes were significantly upregulated in TNBC cell lines MDA-MB-231 and MDA-MB-468 (p<0.005) as determined by PCR arrays. BafA1 induced dose dependent increase of Notch pathway genes as measured by Notch luciferase reporter assay. To investigate the hypothesis that V-ATPase inhibition activates Notch Signaling by autophagy, we tested the expression of LC3B. BafA1 treatment in MDA-MB-231 cells led to accumulation of LC3B, thereby inhibiting autophagy. V-ATPase inhibition also induced a cytoprotective response by increasing expression of Hif1α, a gene recently reported to activate Notch signaling. Given that both Notch pathway and V-ATPases are involved in tumor cell proliferation, we tested the effect of Baf A1 and Notch Signaling inhibitor - GSI on TNBC cell viability. MDA-MB-231 cells showed a significant decrease in proliferation upon treatment with Baf A1 (p<0.0001) or GSI (p<0.001) as measured by MTT assay. However, combinatorial treatment with BafA1 and GSI was not as efficient, an effect that can be attributed to enhanced Notch Signaling through V-ATPase inhibition. A similar trend was observed with apoptosis induction as measured by Caspase 3/7 activation assay. Effect of V-ATPase inhibition on cell proliferation was corroborated by Concanamycin A, another V-ATPase inhibitor. In summary, our results show that V-ATPase regulates cell survival pathways like Notch Signaling in TNBC. Through this study, we have deciphered a novel role of V-ATPase inhibitors in cell signaling regulation, a finding that may be useful for combinatorial therapy regimens.

Citation Format: Sahithi Pamarthy, Mukesh K. Jaiswal, Arpita Kulshrestha, Gajendra Katara, Safaa Ibrahim, Alice Gilman-Sachs, Kenneth D. Beaman. The baffling effect of bafilomycin on Notch signaling in triple-negative breast cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4939. doi:10.1158/1538-7445.AM2015-4939

The Rubber Stopper: A Simple and Inexpensive Technique to Prevent Pin Tract Infection following Kirschner Wiring of Supracondylar Fractures of Humerus in Children

Percutaneous pinning after closed reduction is commonly used to treat supracondylar fractures of the humerus in children. Minor pin tract infections frequently occur. The aim of this study was to prevent pin tract infections using a rubber stopper to reduce irritation of the skin against the Kirschner (K) wire following percutaneous pinning. Between July 2011 and June 2012, seventeen children with closed supracondylar fracture of the humerus of Gartland types 2 and 3 were treated with this technique. All patients were treated with closed reduction and percutaneous pinning and followed up prospectively. Only one patient, who was a hyperactive child, developed pin tract infection due to softening of the plaster slab. We found using the rubber stopper to be a simple and inexpensive method to reduce pin tract infections following percutaneous pinning.

Inhibition of aminoglycoside-induced nephrotoxicity in rats by polyanionic peptides

In the present study, we compared poly-L-Asp with poly-L-Glu and poly-D-Glu in vitro and in vivo for their ability to inhibit the GM-induced nephrotoxicity. In vitro, all three polyanions (i) bound GM over a wide range of pH; (ii) displaced GM previously bound to negatively charged phospholipid bilayers at acid pH (i.e. under the conditions prevailing in lysosomes in vivo), and thereby (iii) decreased the inhibitory potency of GM towards lysosomal phospholipase A1. Thus, one was tempted to predict that all three polyanions would have the potential of protecting against AG-induced nephrotoxicity. However, when co-administered to rats with GM, poly-L-Asp and poly-D-Glu completely suppressed the development of lysosomal phospholipidosis, as assessed by biochemical criteria and increased drug accumulation, whereas poly-L-Glu did not offer such protection despite a relatively lower increase in drug accumulation levels. Histoautoradiography also confirmed that poly-L-Asp, but not poly-L-Glu, was a nephroprotectant against the tissue proliferative response induced by GM. Morphologically, poly-L-Asp almost completely and poly-D-Glu totally prevented the accumulation of myeloid bodies in lysosomes. In vitro incubation in the presence of purified lysosomal extracts revealed marked differences in the hydrolysis rate of these peptides (poly-D-Glu:poly-L-Asp:poly-L-Glu = 1:1.2:16.9). Assuming that all three polyanionic peptides are transported and accumulated in lysosomes to the same extent, these results not only suggest that their stability in lysosomes is an essential requisite for protection against lysosomal phospholipidosis, but also strengthen our hypothesis that the site of action of poly-L-Asp is inside the lysosomes but not at the level of the renal membranes. In addition, poly-D-Glu alone or combined with GM induced another type of morphological lesion, not related to AG-induced nephrotoxicity which, to our knowledge, has not yet been described.

Transfer of ²¹⁰Po, ²¹⁰Pb and ²³⁸U from some medicinal plants to their essential oils

Essential oils were extracted from 35 medicinal plants used by Syrians, organic compounds were determined in these oils and concentrations of (210)Po (210)Pb and (238)U were determined in the original plants and in the essential oils. The results showed that the highest activity concentrations of (210)Po and (210)Pb were found in leaves with large surfaces and in Sage were as high as 73.5 Bq kg(-1) and 73.2 Bq kg(-1), respectively. The activity concentration of (238)U was as high as 4.26 Bq kg(-1) in Aloe. On the other hand, activity concentrations of (210)Po ranged between 0.2 and 71.1 Bq kg(-1) in extracted essential oils for Rosemary and False yellowhead, respectively. The activity concentration of (210)Pb reached 63.7 Bq kg(-1) in Aloe oil. The activity concentrations of (238)U were very low in all extracted oils; the highest value was 0.31 Bq kg(-1) in peel of Orange oil. The transfer of (210)Po and (210)Pb from plant to its oil was the highest for Eugenia; 7.1% and 5.5% for (210)Po and (210)Pb, respectively. A linear relationship was found between the transfer factor of radionuclides from plant to its essential oil and the chemical content of this oil.

STUDI KINETIKA DEHIDRASI RISINOLEAT DARI MINYAK JARAK

 ABSTRACT Dehydration of ricinoleic of castor oil into mixed of linoleic acid (LA) and conjugated linoleic acid (CLA) named DCO (dehydrated Castor Oil) was conducted by using P2O5 at temperature 125°C and 175°C were held time variety at 1, 2, 3 and 4 hour. Dehydration was maintained under reduced pressure 50 to 70 mmHg, gentle bubbling with Nitrogen , magnetically stirred between 800 to 1000 rpm and 0.1 g Zn powder as antipolymerization agent. The concentration changes of the ricinoleic and DCO followed by contrentation GC. The elucidation of ricinoleic, LA and CLA were analyzed by GC-MS. The result showed that reaction was first order with rate constant (k) was 1.0 × 10-2 h-1 at 125°C and 0.9631 h-1 at 175°C and energy of activation (Ea) was 191.152 kJmol-1and Keywords: Dehydration, Kinetic, Ricinoleic, LA and CLA. 

STUDI PENGARUH WAKTU, SUHU DAN JUMLAH DEHIDRATOR PADA DEHIDRASI RISINOLEAT MINYAK JARAK DENGAN P2O5

 The aims of study are to optimize the reaction’s parameters i.e. time, temperature, and amount of dehydrator’s agent on the dehydration of ricinoleic of castor oil into dehydrated castor oil (DCO) by mean P2O5. DCO is the mixed of linoleic acid (LA) and conjugated linoleic acid (CLA). Dehydration were carried out using various of time, temperature, and amount of dehydrator. The reaction medium was maintained under vacuum, gentle bubbling with nitrogen, magnetically stirred and used Zn’s powder as antipolymerization’s agent. The changes composition of DCO were analyzed by GC, and identification by FTIR and GC-MS and compared to CLA’s standard. Best result were obtain for 4 h, at 200°C and 3% (w/w) P2O5. DCO compositions were : 1.02% of (9c/t – 12c/t) linoleic; 41.97% of (9c/t – 12t/c) linoleic ; 19.50% of (9c/t – 11t/c) CLA ; 19.79% of (9t – 11t) CLA; and 0.90% of residual’s of ricinoleic. The yields of dehydration was 98.98%, and the decreased 92.98% intensities of –OH wives number in FTIR spectra’s castor oil comparison with DCO to indicated transform of ricinoleic by dehydration. Both wave number of alkenes (C=C) at FTIR DCO spectra was indicated to formed of conjugated alkenes (CLA). The ratio of CLA : linoleic was 0.92 : 1 with achievement of 63.5% relatively to CLA standard with ratio of CLA : linoleic was 1.45 : 1. Keywords: Time, Temperature, Amount of dehydrator, Dehydration of ricinoleic   

ALK5 inhibition maintains islet endothelial cell survival but does not enhance islet graft revascularisation or function

Islet transplantation is a potential treatment for Type 1 diabetes but long term graft function is suboptimal. The rich supply of intraislet endothelial cells diminishes rapidly after islet isolation and culture, which affects the revascularisation rate of islets after transplantation. The ALK5 pathway inhibits endothelial cell proliferation and thus inhibiting ALK5 is a potential target for improving endothelial cell survival. The aim of the study was to establish whether ALK5 inhibition prevents the loss of intraislet endothelial cells during islet culture and thus improves the functional survival of transplanted islets by enhancing their subsequent revascularisation after implantation. Islets were cultured for 48 h in the absence or presence of 2 different ALK inhibitors: SB-431542 or A-83-01. Their vascular density after culture was analysed using immunohistochemistry. Islets pre-cultured with the ALK5 inhibitors were implanted into streptozotocin-diabetic mice for either 3 or 7 days and blood glucose concentrations were monitored and vascular densities of the grafts were analysed. Islets cultured with ALK5 inhibitors had higher vascular densities than control-cultured islets. Three days after implantation, endothelial cell numbers in islet grafts were minimal, irrespective of treatment during culture. Seven days after implantation, endothelial cells were evident within the islet grafts but there was no difference between control-cultured islets and islets pre-treated with an ALK5 inhibitor. Blood glucose concentrations were no different between the treatment groups. In conclusion, inhibition of ALK5 improved intraislet endothelial cell numbers after islet culture, but this effect was lost in the early post-transplantation period.

Warfarin or dabigatran for treatment of atrial fibrillation

BACKGROUND

New antithrombotic drugs for prevention and treatment of thromboembolic disorders in AF that are less demanding on local staff and facilities than warfarin should be welcomed if proved successful.

OBJECTIVES

The comparative value and possible dangers of substituting the new drug dabigatran as a replacement remain to be established. Its safety and effectiveness must be reviewed and assessed by further study.

METHODS

Clinical results of the European Action on Anticoagulation (EAA) computer-assisted dosage study and the Randomized Evaluation of Long-Term Anticoagulation Therapy (RE-LY) trial have been compared.

RESULTS

Clinical events were lower in patients on warfarin in the EAA study compared to patients on both warfarin and dabigatran in the RE-LY study.

CONCLUSION

Evaluations should recognize optimum requirements for safe and effective administration of both types of drug. In the warfarin arm improvements in effectiveness and safety recently introduced (i.e. the PT/INR line and variance growth analysis) should be included as they have been shown to be successful in improved prediction of bleeding and further thromboembolism. The incidence of bleeding with dabigatran, for which there is no antidote, will require evaluation.

Lupus - the cold, hard facts

Systemic lupus erythematosus (SLE) is a multisystem chronic disease with a multitude of clinical presentations. We review and synthesize how an environmental insult (exposure to extreme cold for a short duration) and endogenous (antiphospholipid antibody syndrome, SLE vasculitis) insults in a susceptible young female with lupus (peripheral arterial disease, smoking, SLE) led to a perfect storm resulting in catastrophic injuries (frostbite).