Mitochondrial KATP Channels Control Glioma Radioresistance by Regulating ROS-Induced ERK Activation

Malignant glioma is the most prevalent form of malignant brain tumor. Although radiotherapy is widely used in glioma treatment, the radioresistance of glioma cells limits the success of the glioma treatment. The lack of effective targets and signaling pathways to reverse glioma radioresistance is the critical obstacle in successful treatment. In this study, we demonstrate that mitochondrial ATP-sensitive potassium channels (mtK(ATP) channels) are overexpressed in glioma cells and are closely related to the malignancy grade and the overall survival of the patients. Importantly, we showed that mtK(ATP) channels could control glioma radioresistance by regulating reactive oxygen species (ROS)-induced ERK activation. The inhibition of mtK(ATP) channels suppresses glioma radioresistance by inhibiting ERK activation both in vitro and in vivo. These findings reveal the important roles of the mitochondria and mtK(ATP) channels as key regulators in the radioresistance of glioma cells, and suggest that mtK(ATP) channel blockers and MAPK/ERK kinase (MEK) inhibitors are potential targets for drug development of glioma treatments.

The association between HLA-DQB1 polymorphism and antituberculosis drug-induced liver injury: a Case-Control Study

WHAT IS KNOWN AND OBJECTIVE

Research on genetic factors associated with antitubercular drug-induced liver injuries (ATLI) has been reported. However, most of the research has focused on genetic polymorphisms of genes encoding metabolic enzymes, including NAT2, GST and CYP450. It is probable that the immune system also contributes to the onset of drug adverse effects. A few small studies have explored the possible association of HLA genes with drug-induced liver injuries (DILI), but more supportive evidence from larger studies or prospective cohort designs is needed. We aim to explore the possible association of HLA-DQB1 gene polymorphisms with ATLI in a case-control study.

METHODS

A case-control study design was used. ATLI was recorded in a prospectively followed-up cohort of patients receiving antituberculosis treatment. Identified cases were matched with control tuberculosis patients within the same cohort but with no adverse effects in 1 : 1 ratio. We used the sequence-based typing method to determine the HLA-DQB1 genotypes. Odds ratios (OR) and 95% confidence intervals (CI) were calculated using conditional logistic regression.

RESULTS AND DISCUSSION

Eighty-nine cases were included in this case-control study. HLA-DQB1 typing was successful for 177 subjects. No association between frequency of HLA-DQB1 genotypes and ATLI was statistically significant in univariate analyses. Multivariate analysis using the conditional logistic regression model revealed that the individuals with two DQB1*05 alleles were at higher risk of ATLI than control subjects. The OR was 5.28 adjusted for use of liver protective drugs and weight (10/88 VS 2/88, 95% CI: 1.134-24.615, P = 0.034). Analysis according to the liver injury type showed that both mixed liver injury patients and cholestatic/mixed liver injury patients had higher proportions of DQB1*05 : 02 alleles (P values were 0.028 and 0.005, respectively).

WHAT IS NEW AND CONCLUSION

This study suggests that ATLI was more likely in subjects of HLA-DQB1*05/*05 genotype. Further studies are needed to verify this association.

Removing arsenic from groundwater in Cambodia using high performance iron adsorbent

In Cambodia, groundwater has been contaminated with arsenic, and purification of the water is an urgent issue. From 2010 to 2012, an international collaborative project between Japan and Cambodia for developing arsenic-removing technology from well water was conducted and supported by the foundation of New Energy and Industrial Technology Development Organization, Japan. Quality of well water was surveyed in Kandal, Prey Veng, and Kampong Cham Provinces, and a monitoring trial of the arsenic removal equipment using our patented amorphous iron (hydr)oxide adsorbent was performed. Of the 37 wells surveyed, arsenic concentration of 24 exceeded the Cambodian guideline value (50 μg L(-1)), and those of 27 exceeded the WHO guideline for drinking water (10 μg L(-1)). Levels of arsenic were extremely high in some wells (>1,000-6,000 μg L(-1)), suggesting that arsenic pollution of groundwater is serious in these areas. Based on the survey results, 16 arsenic removal equipments were installed in six schools, three temples, two health centers, four private houses, and one commune office. Over 10 months of monitoring, the average arsenic concentrations of the treated water were between 0 and 10 μg L(-1) at four locations, 10-50 μg L(-1) at eight locations, and >50 μg L(-1) at four locations. The arsenic removal rate ranged in 83.1-99.7%, with an average of 93.8%, indicating that the arsenic removal equipment greatly lower the risk of arsenic exposure to the residents. Results of the field trial showed that As concentration of the treated water could be reduced to <10 µg L(-1) by managing the As removal equipment properly, suggesting that the amorphous iron (hydr)oxide adsorbent has high adsorbing capacity for As not only in the laboratory environment but also in the field condition. This is one of the succeeding As removal techniques that could reduce As concentration of water below the WHO guideline value for As in situ.

Limited human-to-human transmission of avian influenza A(H7N9) virus, Shanghai, China, March to April 2013

In April 2013, two members of one family were successively confirmed as cases of avian influenza A(H7N9) virus infection in Shanghai, China. Respiratory specimens from the two cases and their close contacts were tested using real-time reverse-transcription (RT)-PCR. Paired serum specimens from contacts were tested by haemagglutination inhibition assay and microneutralisation test. The index patient developed severe pneumonia. Her husband presented with pneumonia shortly thereafter. Both cases had highly similar clinical features and infection with A(H7N9) virus was confirmed in both cases by genetic analysis. Phylogenetic analysis revealed a high level of similarity between the sequences from the two patients and environmental samples collected from wet markets in Minhang and Changning districts. Six samples from the Changning wet market were confirmed as A(H7N9) positive. Of 27 close contacts, one developed mild respiratory symptoms and another tested positive for A(H7N9) antibodies, but both were negative by real-time RT-PCR. The other 25 close contacts of both cases were A(H7N9) negative. Limited human-to-human transmission of the virus most likely occurred in the family cluster. However, other close contacts did not test positive for the virus, suggesting limited potential for extensive human-to-human transmission of the virus.

Association of PAX4 genetic variants with oral antidiabetic drugs efficacy in Chinese type 2 diabetes patients

The aim of this study was to investigate the association of PAX4 variants with therapeutic effect of oral antidiabetic drugs in Chinese type 2 diabtes mellitus (T2DM) patients. A total of 209 newly diagnosed T2DM patients were randomly assigned to treatment with repaglinide or rosiglitazone for 48 weeks, and the therapeutic effects were compared. In the rosiglitazone cohort, rs6467136 GA+AA carriers showed greater decrease in 2-h glucose levels (P=0.0063) and higher cumulative attainment rates of target 2-h glucose levels (Plog rank=0.0093) than GG homozygotes. In the subgroup with defective β-cell function, rs6467136 GA+AA carriers exhibited greater decrements of 2-h glucose level and improvement of homeostasis model assessment of insulin resistance (P=0.0143). Moreover, GA+AA carriers were more likely to attain the target fasting and 2-h glucose level (Plog rank=0.0091 and 0.007, respectively). However, these single-nucleotide polymorphisms showed no effect on repaglinide efficacy. In conclusion, PAX4 variant rs6467136 was associated with the therapeutic effect of rosiglitazone in Chinese T2DM patients.

Expression of heat shock protein 90 alpha (Hsp90α) in primary neonatal rat myocardial cells exposed to various periods of heat stress in vitro

The objective of this study was to investigate the mechanism of heat shock protein 90 alpha (Hsp90α) protection against heart damage resulting from heat stress by detecting Hsp90α mRNA, Hsp90α protein, protein localization, and cell damage in primary myocardial cells of neonatal rats in response to heat stress in vitro. The cells were heat-stressed at 42°C in an incubator with 95% air and 5% CO2 for different periods. Levels of Hsp90α, protein localization, enzymes, and cytopathological lesions were detected using Western blot, immunocytochemistry enzymatic assays, and cytopathological techniques. Aspartate aminotransferase, lactate dehydrogenase, and creatine kinase enzyme levels were elevated during heat stress, and acute cellular lesions that were characterized by vacuolar degeneration and necrosis were observed. Hsp90α levels decreased between 10 and 60 min of heat stress and increased after 360 and 480 min, while Hsp90α mRNA decreased after 360 min. These results indicate that heat stress might induce irreversible damage in certain myocardial cells. The elevated Hsp90α level at the end of heat stress and its positive signal in the cytoplasm of myocardial cells after heat stress could be associated with its protective role. Additionally, the consumption of Hsp90α exceeded its production in the first period of treatment.

Detection of autoantibodies to a panel of tumor-associated antigens for the diagnosis values of gastric cardia adenocarcinoma

To evaluate the diagnostic values of using autoantibodies in sera to a panel of eight tumor-associated antigens (TAAs) of P53, Koc, P62, C-myc, IMP1, Survivn, P16 and Cyclin B1 full-length recombinant proteins for early detection of patients with gastric cardia adenocarcinoma (GCA) and high-risk subjects screening. Enzyme-linked immunosorbent assay was used to detect autoantibodies against the eight selected TAAs in 383 sera samples from four groups, including 140 subjects with normal gastric cardia epithelia (NOR), 76 patients with chronic atrophic gastritis (CAG), 79 patients with gastric cardia dysplasia (DYS) and 88 patients with GCA. In addition, the expression of the eight antigens was analyzed in gastric cardia tissues by immunohistochemical method. The individual autoantibodies to six TAAs (P53, P62, IMP1, Survivn P16 and Cyclin B1) were significantly higher in sera from patients with GCA than that in normal subjects (P < 0.05). When autoantibody assay successively accumulated to seven TAAs (P53, Koc, P62, C-myc, IMP1, Survivn and P16), a stepwise increased detection frequency of autoantibodies was found in the four sera groups (13% in NOR, 39% in CAG, 46% in DYS, and 64% in GCA, respectively), the risks to CAG, DYS and GCA steadily increased about 4.4-, 5.7- and 12.0-fold. The sensitivity and the specificity for autoantibodies against the seven TAAs in diagnosing GCA reached up to 64% and 87%, respectively. The area under the receiver operating characteristic curve for the seven anti-TAA autoantibodies was 0.73 (95%CI: 0.68-0.78) No more increase in sensitivity was found with the addition of new anti-TAA autoantibodies. A combination detection of autoantibodies to TAAs might be helpful to distinguish GCA patients from normal subjects and the patients with gastric cardia precancerous lesions. In addition, further studies in patients with GCA and precancerous lesions using enlarged TAA panels might improve the sensitivity and specificity of cancer detection and high-risk subjects screening.

Mitochondria-targeted antioxidant peptide SS31 protects the retinas of diabetic rats

Oxidative stress is one of the main contributors in the pathogenesis of diabetic retinopathy. The aim of this study is to investigate the effects of SS31 which is a mitochondria-targeted antioxidant peptide on the retinas of streptozotocin (STZ)-induced diabetic rats. Two weeks after induction of diabetes, SS31 (3 mg/kg) or the same volume of normal saline (N.S) was injected subcutaneously into the back of diabetic rats every day. Four months later, the integrity of inner blood retinal barrier (iBRB) was measured by Evans blue perfusion. The expression and distribution of claudin-5, occludin, acrolein, 8-OHdG and nitrotyrosine in the rat retinas were detected by immunofluorescent staining. Retinal ultrastructures were observed by transmission electron microscopy. The protein level of VEGFR2, Trx-2, Bcl-2, Bax, caspase-3, p53, and NF-κB in the rat retinas were assayed by western blot. Four months after subcutaneous injection, the diabetic rats treated with SS31 had better structures of retinal ganglion cells, thinner capillary basement membrane, less iBRB leakage, more uniform staining of claudin-5 and occludin in the retinal vessels, lower levels of acrolein, 8-OHdG, nitrotyrosine, Bax, caspase-3, p53, and NF-κB, and higher levels of Trx-2 and Bcl-2 in the retinas than those treated with N.S. In conclusion, SS31 could protect the retinal structures and inhibit the breakdown of iBRB by reducing oxidative damage, increasing Trx-2 and Bcl-2 expression, and decreasing p53, NF-κB, Bax, caspase-3, and VEGFR2 expression in the retinas of diabetic rats. SS31 could be a potential new treatment for diabetic retinopathy and other oxidative stress-related diseases.

Anchor placement and subsequent movement in a mesh kit with self-fixating tips: 6-month follow-up of a prospective cohort

OBJECTIVE

To describe the initial placement of Elevate single-incision mesh kit device tips relative to the sacrospinous ligament, and to measure tip movement over a 6-month period from initial placement.

DESIGN

Prospective cohort.

SETTING

Tertiary care urogynaecology centre in Calgary, Canada.

POPULATION

Women electing for surgical management of anterior vaginal wall prolapse.

METHODS

Ten women underwent anterior prolapse repair using the Elevate single-incision mesh kit with a metallic fiducial marker attached to the tips of the surgical device. Women were imaged by magnetic resonance imaging (MRI) within 48 hours of surgery, and again 6 months later to investigate the position of the device tips and change ≥4 mm over the 6-month postoperative period.

MAIN OUTCOME MEASURE(S)

Position of self-fixating tips within 48 hours of surgery, and at six months post-operative.

RESULTS

Anchor insertion was directly into the sacrospinous ligament in 10 of 20 insertion points (50%, 95% CI 27-73%). Movement was most often noted in the cranial-caudal direction: a change in location of ≥4 mm was observed for 8/20 anchors (40%, 95% CI 19-64%). Cranial-caudal movement was observed less frequently among sacrospinous anchors than among anchors inserted into other pelvic structures (1/10 versus 7/10, P = 0.020, difference in proportion -60%, 95% CI -94 to -26%). PFDI-20 scores improved statistically significantly by 6 months (P = 0.008, mean change -62.9%, 95% CI -105.1 to -20.7%), but PFIQ-7 scores did not change statistically significantly over the same time period (P = 0.523, mean change -12.4%, 95% CI -54.5 to 29.8%).

CONCLUSIONS

The novel self-fixating anchoring tips of this single-incision mesh kit do not reliably anchor into the sacrospinous ligament. The tips have been shown to move with time, although not all cases of anchor movement were associated with recurrent prolapse.

Abstract P5-17-01: A definition of a high-risk early-breast cancer population based on data from the collaborative trials in neoadjuvant breast cancer (CTNeoBC) meta-analysis

Background: Pathological complete response (pCR) is a proposed surrogate endpoint for predicting long-term clinical benefit on endpoints such as event-free survival (EFS) or overall survival (OS). The CTNeoBC meta-analysis did not validate the surrogacy of pCR for EFS or OS, and there is no precedent for its use as a regulatory endpoint in oncology. Use of the accelerated approval pathway has been proposed for neoadjuvant therapies that substantially improve pCR as a means to expedite widespread access to highly effective therapies for high-risk, early breast cancer. Potential risks of this approach include approving an agent that ultimately does not demonstrate clinical benefit and, in the interim, exposing curable patients to the toxicity of therapy without certainty of benefit. To mitigate the risks of this pathway, enrollment to neoadjuvant trials intended to support accelerated approval should be restricted to patients presenting with high-risk early-stage breast cancer. The 5-year EFS rate by breast cancer subtype in the CTNeoBC meta-analysis population is presented. Methods: We identified 12 neoadjuvant randomized trials (N = 12,993) with pCR clearly defined and long-term follow-up available for EFS and OS. Trials included AGO 1 (n = 668), ECTO (n = 1355), EORTC 10994/BIG 1-00 (n = 1856), GeparDuo (n = 907), GeparQuattro (n = 1495), GeparTrio (n = 2072), GeparTrio-Pilot (n = 285), NOAH (n = 234), NSABP B18 (n = 760), NSABP B27 (n = 2411), PREPARE (n = 733), and TECHNO (n = 217). The key objective of this analysis was to establish a definition of “high-risk” based on the Kaplan-Meier estimates of the 5-year EFS rate in the different clinical breast cancer subtypes (hormone receptor-positive, HER2-positive and triple-negative) analyzed by tumor stage and tumor grade at presentation. Results: The 5-year EFS rate was less than 65% in all the breast cancer subtypes with stage III disease. For patients with stage II disease, the impact of tumor grade varied by hormone receptor status. Patients with hormone receptor-negative breast cancer, regardless of HER2 status had a poor prognosis that was independent of tumor grade. For patients with hormone receptor-positive tumors, regardless of HER2 status, high grade histology was associated with an increased risk of recurrence.

5-year Event-Free Survival Rate (EFS) 5-year EFS Rate Estimate (95% confidence interval)TNMStage IIStage III Grade IIGrade IIIGrade IIGrade IIIHormone Receptor + HER2-83% (80%, 85%)71% (65%, 77%)63% (58%, 69%)51% (42%, 59%)HER2+ HR+81% (75%, 86%)69% (60%, 76%)50% (41%, 59%)48% (37%, 59%)HER2+ HR-61% (51%, 70%)66% (57%, 73%)58% (46%, 69%)46% (36%, 55%)Triple Negative66% (58%, 72%)72% (67%, 76%)38% (27%, 48%)37% (29%, 45%)

Conclusions: This analysis estimated the 5-year EFS rate in the breast cancer subtypes from the CTNeoBC meta-analysis population. The HER2-positive population in the meta-analysis was at particularly high risk because most of the patients had locally advanced breast cancer and only 39% of these patients received trastuzumab therapy. We propose defining less than 75% 5-year EFS rate as “high-risk” for the purposes of designing neoadjuvant trials that intend to use pCR to support accelerated approval.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-17-01.

Topical (intra-articular) tranexamic acid reduces blood loss and transfusion rates following total hip replacement: a randomized controlled trial (TRANX-H)

BACKGROUND

Approximately one-third of patients undergoing total hip replacement surgery require one to three units of blood postoperatively. Tranexamic acid is a synthetic antifibrinolytic agent that has been successfully used intravenously to control bleeding after total hip replacement. A topical application is easy to administer, provides a maximum concentration of tranexamic acid at the bleeding site, and is associated with little or no systemic absorption of the tranexamic acid.

METHODS

A double-blind, randomized controlled trial of 161 patients undergoing unilateral primary total hip replacement investigated the effect of topical (intra-articular) application of tranexamic acid on blood loss. The primary outcome was the blood transfusion rate. Secondary outcomes included the drain blood loss, hemoglobin concentration drop, generic quality of life (EuroQol), Oxford Hip Score, length of stay, a cost analysis, and complications.

RESULTS

Tranexamic acid reduced the absolute risk of blood transfusion by 19.6% (95% confidence interval [CI], 6.9% to 32.1%; p = 0.004), from 32.1% to 12.5%, and reduced blood loss by 129 mL (95% CI, 47 to 211 mL; p = 0.002), the hemoglobin concentration drop by 0.84 g/dL (95% CI, 0.41 to 1.27; p &lt; 0.0001), the length of stay by 1.0 days (95% CI, -0.2 to 2.3 days; p = 0.109), and the cost per episode by £305 (95% CI, £0 to £610; p = 0.05). (In 2010, £1 = 1.5 U.S. dollars.) Oxford Hip Scores and EuroQol scores were similar at three months.

CONCLUSIONS

Topically applied tranexamic acid was effective in reducing blood loss and the need for blood transfusion following total hip replacement, avoiding the potential complications of intravenous tranexamic acid administration.

LEVEL OF EVIDENCE

Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Retinoic acid alters the proliferation and survival of the epithelium and mesenchyme and suppresses Wnt/β-catenin signaling in developing cleft palate

Retinoic acid (RA) contributes to cleft palate; however, the cellular and molecular mechanisms responsible for the deleterious effects on the developing palate are unclear. Wnt signaling is a candidate pathway in the cleft palate and is associated with RA in organ development; thus, we aim to investigate whether RA-induced cleft palate also results from altered Wnt signaling. Administration of RA to mice altered cell proliferation and apoptosis in craniofacial tissues by regulating molecules controlling cell cycle and p38 MAPK signaling, respectively. This altered cell fate by RA is a crucial mechanism contributing to 100% incidence of cleft palate. Moreover, Wnt/β-catenin signaling was completely inhibited by RA in the early developing palate via its binding and activation with RA receptor (RAR) and is responsible for RA-induced cleft palate. Furthermore, PI3K/Akt signaling was also involved in actions of RA. Our findings help in elucidating the mechanisms of RA-induced cleft palate.

Association between KCNQ1 genetic variants and QT interval in a Chinese population

AIM

There is a close link between electrocardiographic ventricular repolarization QT parameters and Type 2 diabetes. The aim of the present study was to assess the effects of QT-related and diabetes-related variants in KCNQ1 on QT interval in a Chinese population.

METHODS

We recruited 2415 patients with Type 2 diabetes and 1163 subjects with normal glucose regulation in the present study. QT interval was obtained and the heart rate-corrected QT interval (QTc) was calculated using Bazett's formula. Four single nucleotide polymorphisms in KCNQ1 were selected (rs12296050, rs12576239, rs2237892 and rs2237895) and genotyped.

RESULTS

In participants with normal glucose regulation, the minor allele T of rs12296050 was associated with a 3.46-ms QTc prolongation under an additive model (P = 0.0109, empirical P = 0.0498). In patients with Type 2 diabetes, we did not find any association for the single nucleotide polymorphisms.

CONCLUSIONS

Our findings indicate that KCNQ1 is associated with QT interval in a Chinese population with normal glucose regulation.

Two-step retrograde closed stenting: a novel method for treating canalicular lacerations in Chinese patients

PURPOSE

To evaluate the efficacy of two-step retrograde closed stenting for treating canalicular laceration. methods: Forty-eight consecutive canalicular laceration cases (48 eyes) were randomised and divided into two groups: a one-step group and a two-step group. In the two-step group (23 cases), the first step was performed in the outpatient department and included identifying the medial cut end of the canaliculus and probing under a slit-lamp microscope, followed by a retrograde canalicular stenting assisted by a memory titanium stylet. The second step was canalicular anastomosis, which was performed in the operating room. In the one-step group (25 cases), all of the surgical procedures were performed when preoperative preparations were simultaneously available.

RESULTS

The time elapsed from the doctor visit to the treatment was 4.3 ± 2.4 h in the two-step group and 18.8 ± 6.3 h in the one-step group (P<0.01). The canalicular medial cut ends were found in all cases, but 8.6 ± 3.5 min was needed in the two-step group, and 51.4 ± 24.2 min was needed in the one-step group (P<0.01). The numerical rating scale for pain during surgery was 1.8 ± 1.2 in the two-step group and 5.4 ± 2.2 in the one-step group (P<0.01). One case (2.63%) in the two-step group and nine cases (36%) in the one-step group required other assisted methods to locate the medial cut end (P=0.007). Twenty-one cases (91.3%) in the two-step group and 20 cases (80%) in the one-step group achieved patent lacrimal drainage systems during a 12-month follow-up (P=0.528).

CONCLUSIONS

The two-step canalicular anastomosis method allows an early search for the medial cut end of the canaliculus and improves the chances of finding it; it is also a quicker, less invasive method for treating canalicular lacerations.