Abstract P3-12-09: CYP2D6*10 genotype was associated with worse outcome of premenopausal breast cancer patients receiving adjuvant tamoxifen but not toremifene: A single institution expericence

Background: Tamoxifen(TAM), a selective estrogen receptor modulator(SERM), is the most widely used adjuvant endocrine therapy for premenopausal breast cancer patients. Cytochrome P-450(CYP450) enzyme, CYP2D6, is involved in the conversion of tamoxifen to endoxifen which is one of the main active metabolites of tamoxifen in vivo. Variants of CYP2D6 gene may result in a decreased enzyme activity and lead to poor prognosis of the patients. Different from caucasians, the most common polymorphism among Chinese women is allelic variant *10, which generates a 188 C to T transition, resulting in a lower activity of the enzyme. Based on some retrospective studies, tamoxifen-treated patients with the CYP2D6*10 T/T genotype have a worse clinical outcome. Toremifene(TOR), another kind of SERM is not metabolited by CYP2D6 enzyme thus may not be influenced by its polymorphism. We conducted this study to validate the association between CYP2D6*10 genotype and the outcomes of patients receiving TAM and TOR respectively.

Methods: A total of 276 patients with primary early-stage ER-positive breast cancer received adjuvant tamoxifen (n=169) or toremifene (n=107) therapy at Natinal Cancer Center from 2004-2012 were analyzed. All patients had received 5-year endocrine therapy after completion of surgery. TaqMan SNP genotyping assays was performed on CYP2D6*10 from blood samples. The association of CYP2D6 *10 genotype with disease free survival (DFS) and clinicopathological characteristics was analyzed in patients receiving tamoxifen and toremifen.

Results: 32.6% (90 of 276) of the patients were homozygous for wild-type C/C genotype, 47.1% (130 of 276) were heterozygous for C/T genotype, and 20.3% (56 of 276) were homozygous for variant T/T genotype. The frequency of CYP2D6 *10 allele in our study was 43.8%. The 5-year DFS rate for tamoxifen and toremifene treatment group were 81.6% and 83.2% respectively. There was no significant difference of DFS between the two groups(P=0.274). Among 169 patients in tamoxifen group, 5-year DFS rate was considerably lower in patients with homozygous variant T/T genotype than those with wild-type C/C or C/T genotype (73.4% versus 83.2%, P=0.004). And the T/T genotype was found to be a significant prognostic marker for DFS in multivariate analysis (hazard ratio = 4.7; P<0.001) after adjusting for patient's characteristics mentioned above. For the toremifene group, there was no difference of DFS between T/T genotype and the others(P=0.332). For all the 56 homozygous variant T/T genotype patients, patients receiving toremifene treatment had a much higher 5-year DFS rate than those receiving tamoxifen but unfortunately it was not statistically significant (90.0% versus 73.4%, P=0.192).

Conclusions: About one fifth of Chinese breast cancer patients had homozygous T/T genotype which might get less benefit from TAM adjuvant treatment. Toremifene may be a better option for this kind of patients. Further large-scale prospective clinical studies are warranted to validate this concept.

Citation Format: Lan B, Ma F, Fan Y, Zhai X, Xu B. CYP2D6*10 genotype was associated with worse outcome of premenopausal breast cancer patients receiving adjuvant tamoxifen but not toremifene: A single institution expericence [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P3-12-09.

Quality of meta-analyses in major leading orthopedics journals: A systematic review

BACKGROUND

Meta-Analyses are the basis of professional and healthcare agencies recommendations and have a growing importance. Quality of meta-analyses has been investigated in some medical fields but to our best knowledge this issue remains under investigated in orthopedics. Therefore, we performed a systematic analysis to: 1) after the introduction of PRISMA statement as a comprehensive guideline and the use of the AMSTAR tool as the standard for sufficient review methodology, has the quality of MAs improved because of that? 2) have some general characteristics influenced the quality of MAs (country, funding source, number of authors)?

MATERIAL AND METHODS

We systematically searched the meta-analyses in the top four journals with the impact factor (2015) as following: JBJS, Osteoarthritis Cartilage Arthroscopy and Clin Orthop Relat Res from 2005 to 2008 and from 2012 to 2015. Likewise from 2012-2015, we also analyzed the meta-analyses from OTSR. Characteristics were extracted based on the PRISMA statement and the AMSTAR tool. Country, number of authors, funding source were also extracted.

RESULTS

A total of 154 meta-analyses were included in the present study. Score with PRISMA statement and the AMSTAR checklist were 20.86±3.04 out of a maximum of 27 and 7.86±1.55 out of a maximum of 11. The best journal was OTSR according to the PRISMA (23.06±1.92) and AMSTAR (9.13±0.87) scores. And the worst journal was Clin Orthop Relat Res according to the PRISMA score (19.4±2.70) and JBJS according to the AMSTAR score (6.78±1.65). Twelve items showed significant difference in the PRISMA statement, and five items in the AMSTAR checklist. Integral score of PRISMA statement and AMSTAR checklist has a significant difference between 2005-2008 and 2012-2015. The MAs reported from U.S. (56, 36.4%) were more than any other region in the world. And the MAs published by Asia/Oceania increased remarkably between these two period times [from (4, 10.8%) to (45, 38.5%)].

CONCLUSION

This study showed that methodological reporting quality of meta-analyses in the major orthopedics journals has improved after the publication of the PRISMA statement.

LEVEL OF EVIDENCE

Level III.

Enzyme activation through the utilization of intrinsic dianion binding energy

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We consider 'the proposition that the intrinsic binding energy that results from the noncovalent interaction of a specific substrate with the active site of the enzyme is considerably larger than is generally believed. An important part of this binding energy may be utilized to provide the driving force for catalysis, so that the observed binding energy represents only what is left over after this utilization' [Jencks,W.P. (1975) Adv. Enzymol. Relat. Areas. Mol. Biol. , , 219-410]. The large ~12 kcal/mol intrinsic substrate phosphodianion binding energy for reactions catalyzed by triosephosphate isomerase (TIM), orotidine 5'-monophosphate decarboxylase and glycerol-3-phosphate dehydrogenase is divided into 4-6 kcal/mol binding energy that is expressed on the formation of the Michaelis complex in anchoring substrates to the respective enzyme, and 6-8 kcal/mol binding energy that is specifically expressed at the transition state in activating the respective enzymes for catalysis. A structure-based mechanism is described where the dianion binding energy drives a conformational change that activates these enzymes for catalysis. Phosphite dianion plays the active role of holding TIM in a high-energy closed active form, but acts as passive spectator in showing no effect on transition-state structure. The result of studies on mutant enzymes is presented, which support the proposal that the dianion-driven enzyme conformational change plays a role in enhancing the basicity of side chain of E167, the catalytic base, by clamping the base between a pair of hydrophobic side chains. The insight these results provide into the architecture of enzyme active sites and the development of strategies for the de novo design of protein catalysts is discussed.

The relationship between intracranial pressure and neurocognitive function before and after the repair of a skull injury

OBJECTIVE

This study examines the relationship between intracranial pressure (ICP) changes after skull injury repair and neurocognitive function before and after the repair.

PATIENTS AND METHODS

Sixty patients undergoing skull injury repair participated in the study. A non-invasive detection analyzer was used to detect the ICP 2 days before operation, 10 days after the operation and one month after the operation in all patients. Additionally, the mean cerebral blood flow velocities (MV) in the internal carotid and the medial cerebral arteries were detected using a transcranial Doppler ultrasound (TCD). The neurological and cognitive functions were assessed using the NIHSS and the MMSE scales, respectively. And finally, an ELISA assay was used to detect the plasma insulin-like growth factor (IGF)-1 and beta-amyloid peptide (Ab) levels.

RESULTS

The results showed that all parameters studied improved significantly and continuously after surgery.

CONCLUSIONS

We suggest that the improvement in the ICP values and the neurocognitive functions are related to the resulting decreased expression levels of IGF-1 and Abeta after the repair.

Hippocampal UCP2 is essential for cognition and resistance to anxiety but not required for the benefits of exercise

Uncoupling protein-2 (UCP2) reduces oxidative stress by facilitating the influx of protons into mitochondrial matrix, thus dissociating mitochondrial oxidation from ATP synthesis. UCP2 is expressed abundantly in brain areas and plays a key role in neuroprotection. Here, we sought to determine if UCP2 deficiency produces cognitive impairment and anxiety in young mice, and to determine if hippocampal UCP2 is essential for the beneficial effects of voluntary exercise. Antisense oligonucleotide (ASO) was used to produce UCP2 knockdown in mice. Our results firstly showed that UCP2-targeted ASO significantly reduced UCP2 mRNA and protein expression in the hippocampus. ASO treatment impaired learning and memory of the mice in Y-maze, T-maze, and object recognition tests (ORT). ASO-treated mice exhibited more anxiously in OPT, light/dark box test, and elevated plus maze (EPM) than the control mice. We also found that wheel running ameliorated cognitive dysfunction and anxiety-like behaviors in ASO-treated mice. Furthermore, voluntary exercise reversed ASO-induced changes in hippocampal levels of serotonin (5-HT), dopamine (DA), and norepinephrine (NE). However, UCP2 protein in the hippocampus was not correlated with cognitive and anxiolytic benefits of exercise. These findings suggest that hippocampal UCP2 is essential for cognitive function and the resistance to anxiety of mice, but not required for the beneficial effects of exercise.

Selective inhibition of protein kinase C β2 attenuates the adaptor P66 Shc-mediated intestinal ischemia-reperfusion injury

Apoptosis is a major mode of cell death occurring during ischemia–reperfusion (I/R) induced injury. The p66^Shc adaptor protein, which is mediated by PKCβ, has an essential role in apoptosis under oxidative stress. This study aimed to investigate the role of PKCβ₂/p66^Shc pathway in intestinal I/R injury. In vivo, ischemia was induced by superior mesenteric artery occlusion in mice. Ruboxistaurin (PKCβ inhibitor) or normal saline was administered before ischemia. Then blood and gut tissues were collected after reperfusion for various measurements. In vitro, Caco-2 cells were challenged with hypoxia–reoxygenation (H/R) to simulate intestinal I/R. Translocation and activation of PKCβ₂ were markedly induced in the I/R intestine. Ruboxistaurin significantly attenuated gut damage and decreased the serum levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). Pharmacological blockade of PKCβ₂ suppressed p66^Shc overexpression and phosphorylation in the I/R intestine. Gene knockdown of PKCβ₂ via small interfering RNA (siRNA) inhibited H/R-induced p66^Shc overexpression and phosphorylation in Caco-2 cells. Phorbol 12-myristate 13-acetate (PMA), which stimulates PKCs, induced p66^Shc phosphorylation and this was inhibited by ruboxistaurin and PKCβ₂ siRNA. Ruboxistaurin attenuated gut oxidative stress after I/R by suppressing the decreased expression of manganese superoxide dismutase (MnSOD), the exhaustion of the glutathione (GSH) system, and the overproduction of malondialdehyde (MDA). As a consequence, ruboxistaurin inhibited intestinal mucosa apoptosis after I/R. Therefore, PKCβ₂ inhibition protects mice from gut I/R injury by suppressing the adaptor p66^Shc-mediated oxidative stress and subsequent apoptosis. This may represent a novel therapeutic approach for the prevention of intestinal I/R injury.

Effects of Zn deficiency, antioxidants, and low-dose radiation on diabetic oxidative damage and cell death in the testis

Infertility is one of the common complications in diabetic men and mainly due to the loss of germ cells by apoptotic cell death. Although several mechanisms have been proposed to explain the induction of testicular cell death by diabetes, diabetic induction of testicular oxidative stress and damage may be the predominant mechanism responsible for the testicular cell death in diabetes. To explore whether factors that either increase or decrease the testicular oxidative stress and damage will enhance or prevent diabetes-induced testicular cell death, the effect of zinc (Zn) deficiency on diabetes-induced cell death has been examined since Zn was found to play an important role in the protection of testis from oxidative stress and damage. Zn deficiency, induced by its chelator N,N,N,N-Tetrakis(2-pyridylmethyl)-1,2-ethylenediamine, was found to exacerbate diabetes-induced testicular oxidative damage and cell death. In contrast, treatment of diabetic rats with antioxidant N-acetylcysteine or low-dose radiation that can up-regulate endogenous antioxidants significantly attenuated diabetes-induced testicular cell death. These results suggest that diabetes-induced testicular cell death that may eventually cause men's infertility is predominantly mediated by the oxidative stress and damage. To prevent or delay diabetes-caused infertility, diabetic patients should avoid Zn deficiency, and might consider antioxidant supplementation.

Coordinated evolution of the hepatitis B virus polymerase

The detection of compensatory mutations that abrogate negative fitness effects of drug-resistance and vaccine-escape mutations indicates the important role of epistatic connectivity in evolution of viruses, especially under the strong selection pressures. Mapping of epistatic connectivity in the form of coordinated substitutions should help to characterize molecular mechanisms shaping viral evolution and provides a tool for the development of novel anti-viral drugs and vaccines. We analyzed coordinated variation among amino acid sites in 370 the hepatitis B virus (HBV) polymerase sequences using Bayesian networks. Among the HBV polymerase domains the spacer domain separating terminal protein from the reverse-transcriptase domain, showed the highest network centrality. Coordinated substitutions preserve the hydrophobicity and charge of Spacer. Maximum likelihood estimates of codon selection showed that Spacer contains the highest number of positively selected sites. Identification of 67% of the domain lacking an ordered structure suggests that Spacer belongs to the class of intrinsically disordered domains and proteins whose crucial functional role in the regulation of transcription, translation and cellular signal transduction has only recently been recognized. Spacer plays a central role in the epistatic network associating substitutions across the HBV genome, including those conferring viral virulence, drug resistance and vaccine escape. The data suggest that Spacer is extensively involved in coordination of HBV evolution.

Interfacial ferromagnetism and exchange bias in CaRuO3/CaMnO3 superlattices

We have found ferromagnetism in epitaxially grown superlattices of CaRuO(3)/CaMnO(3) that arises in one unit cell at the interface. Scanning transmission electron microscopy and electron energy loss spectroscopy indicate that the difference in magnitude of the Mn valence states between the center of the CaMnO(3) layer and the interface region is consistent with double exchange interaction among the Mn ions at the interface. Polarized neutron reflectivity and the CaMnO(3) thickness dependence of the exchange bias field together indicate that the interfacial ferromagnetism is only limited to one unit cell of CaMnO(3) at each interface. The interfacial moment alternates between the 1 μ(B)/interface Mn ion for even CaMnO(3) layers and the 0.5 μ(B)/interface Mn ion for odd CaMnO(3) layers. This modulation, combined with the exchange bias, suggests the presence of a modulating interlayer coupling between neighboring ferromagnetic interfaces via the antiferromagnetic CaMnO(3) layers.

Participation of haemocytes in fat body degradation via cathepsin L expression

Insect haemocytes are known to participate in innate immunity via the phagocytosis of pathogens. However, the function of haemocytes in tissue remodelling is less understood. We report here that haemocytes play roles in fat body degradation by expressing a cysteine proteinase cathepsin L in the lepidopteran Helicoverpa armigera. During metamorphosis, haemocytes undergo morphological changes by increasing their cell size and transforming their granulocytes into macrogranulocytes. The population of haemocytes also changes with increased number of granulocytes and decreased plasmatocytes. The expression level of cathepsin L in haemocytes, mainly in granulocytes and plasmatocytes, increases. The steroid hormone 20-hydroxyecdysone is able to promote the transformation of granulocytes into macrogranulocytes, and up-regulate the expression level of cathepsin L. The knock-down of the cathepsin L gene by RNA interference in haemocytes in vitro results in deficient granulocytes transforming into macrogranulocytes. Haemocytes are able to enter the decomposed fat body during metamorphosis. The over-expression of the proteinase domain C1A of cathepsin L results in cell apoptosis. Haemocytes, especially macrogranulocytes, undergo apoptosis and cathepsin L is released into haemolymph and the fat body during metamorphosis for fat body decomposition and degradation. These results suggest that cathepsin L is related to the transformation of granulocytes to macrogranulocytes to enter the fat body, and induce haemocyte apoptosis for further tissue degradation.

Involvement of fatty acid metabolism in the hepatotoxicity induced by divalproex sodium

Divalproex sodium is an antiepileptic drug. Hepatotoxicity is one of the most common side effects induced by divalproex sodium. Impaired fatty acid metabolism is considered to play an important role in the drug-induced hepatotoxicity. The sterol regulatory element-binding protein 1c (SREBP-1c) and peroxisome proliferator-activated receptor α (PPARα) are two key transcription factors involved, respectively, in fatty acid synthesis and degradation in liver. In the present study, we investigated the hepatotoxicity induced by divalproex sodium and its potential mechanism. The results indicated that divalproex sodium significantly decreased the cell viability and increased lactate dehydrogenase leakage in hepatocytes. The activities of alanine aminotransferase and aspartate transaminase were increased in hepatocytes treated with divalproex sodium. Furthermore, divalproex sodium activated SREBP-1c and increased the mRNA expressions of acetyl-CoA carboxylase 1, fatty acid synthase and stearoyl-CoA desaturase 1. Divalproex sodium also inhibited PPARα and decreased the messenger RNA expressions of 3-hydroxy-3-methylglutaryl-CoA synthase 2 and carnitine palmitoyltransferase 1A. These results suggest that the hepatotoxicity induced by divalproex sodium may be related with fatty acid synthesis and degradation mediated by SREBP-1c and PPARα in hepatocytes.

Human islet distribution program for basic research at a single center

The Clinical Islet Laboratory at the University of Alberta/Alberta Health Services distributes human islets for basic research when islet preparations fail to meet defined release criteria for transplantation. This report highlights our islet distribution activity for diabetes research over a 3-year period. Shipments of the acinar-enriched fraction for research were not included in this report. In 2010, we distributed 6.3 million islet equivalents (IEQs) of islets through 127 shipments to 8 researchers, locally, nationally, and internationally. The number of preparations for research use was stable over the 3-year period (26, 23, and 29 preparations in 2008, 2009, and 2010, respectively). Islet yield distributed for research per isolation was 201, 212, and 218 × 10(3) IEQs, respectively. The number of basic researchers was stable as well, although there were only 2 researchers before 2007. Recently, each researcher has received fewer islets per shipment (49,820 IEQs in 2010 vs 75,635 IEQs in 2008) but more frequently (21.5 in 2010 vs 11.2 times per year in 2008). This paradigm shift would be desirable for researchers, because in our experience, most require <30,000 IEQs per shipment, and more frequent islet shipments results in a larger sample size for experimentation. After an initial expansion in the number of researchers requesting islets, our islet distribution activity has remained stable over the years in terms of total productivity of islets utilized for research. The current supply-versus-demand ratio in our program appears to be appropriate.

Diabetic inhibition of preconditioning- and postconditioning-mediated myocardial protection against ischemia/reperfusion injury

Ischemic preconditioning (IPC) or postconditioning (Ipost) is proved to efficiently prevent ischemia/reperfusion injuries. Mortality of diabetic patients with acute myocardial infarction was found to be 2-6 folds higher than that of non-diabetic patients with same myocardial infarction, which may be in part due to diabetic inhibition of IPC- and Ipost-mediated protective mechanisms. Both IPC- and Ipost-mediated myocardial protection is predominantly mediated by stimulating PI3K/Akt and associated GSK-3β pathway while diabetes-mediated pathogenic effects are found to be mediated by inhibiting PI3K/Akt and associated GSK-3β pathway. Therefore, this review briefly introduced the general features of IPC- and Ipost-mediated myocardial protection and the general pathogenic effects of diabetes on the myocardium. We have collected experimental evidence that indicates the diabetic inhibition of IPC- and Ipost-mediated myocardial protection. Increasing evidence implies that diabetic inhibition of IPC- and Ipost-mediated myocardial protection may be mediated by inhibiting PI3K/Akt and associated GSK-3β pathway. Therefore any strategy to activate PI3K/Akt and associated GSK-3β pathway to release the diabetic inhibition of both IPC and Ipost-mediated myocardial protection may provide the protective effect against ischemia/reperfusion injuries.

Excite and receive solenoid radiofrequency coil for MRI-guided breast interventions

A radiofrequency coil based on a solenoid design was developed and integrated with a novel device for MR-guided breast interventions using a circumferential approach. The transmit/receive tapered solenoid design conforms to the shape of the pendent breast, and provides open circumferential needle access to breast tissue under rotational symmetry. Phantom and in vivo studies using a healthy volunteer demonstrated a superior uniformity using the tapered solenoid coil compared with a commercial 8-channel diagnostic imaging coil. The solenoid coil design has important advantages due to localized transmit/receive such as B(1) -homogeneity and reduced specific absorption ratio (SAR) especially at high-field strengths. Because it provides open access and a rotationally symmetric local field, the tapered solenoid design can easily be adapted for bilateral imaging and 3D MR-guided breast interventions.

Enhanced ordering temperatures in antiferromagnetic manganite superlattices

The disorder inherent to doping by cation substitution in the complex oxides can have profound effects on collective-ordered states. Here, we demonstrate that cation-site ordering achieved through digital-synthesis techniques can dramatically enhance the antiferromagnetic ordering temperatures of manganite films. Cation-ordered (LaMnO3)m/(SrMnO3)2m superlattices show Néel temperatures (TN) that are the highest of any La(1-x)Sr(x)MnO3 compound, approximately 70 K greater than compositionally equivalent randomly doped La(1/3)Sr(2/3)MnO3. The antiferromagnetic order is A-type, consisting of in-plane double-exchange-mediated ferromagnetic sheets coupled antiferromagnetically along the out-of-plane direction. Through synchrotron X-ray scattering, we have discovered an in-plane structural modulation that reduces the charge itinerancy and hence the ordering temperature within the ferromagnetic sheets, thereby limiting TN. This modulation is mitigated and driven to long wavelengths by cation ordering, enabling the higher TN values of the superlattices. These results provide insight into how cation-site ordering can enhance cooperative behaviour in oxides through subtle structural phenomena.

Metal-insulator transition and its relation to magnetic structure in (LaMnO3)2n/(SrMnO3)n superlattices

Superlattices of (LaMnO3){2n}/(SrMnO3){n} (1<or=n<or=5), composed of the gapped insulators LaMnO3 and SrMnO3, undergo a metal-insulator transition as a function of n, being metallic for n<or=2 and insulating for n>or=3. Measurements of transport, magnetization, and polarized neutron reflectivity reveal that the ferromagnetism is relatively uniform in the metallic state, and is strongly modulated in the insulating state, being high in LaMnO3 and suppressed in SrMnO3. The modulation is consistent with a Mott transition driven by the proximity between the (LaMnO3)/(SrMnO3) interfaces. The insulating state for n>or=3 obeys variable range hopping at low temperatures. We suggest that this is due to states at the Fermi level that emerge at the (LaMnO3)/(SrMnO3) interfaces and are localized by disorder.

Nanoparticle-textured surfaces from spin coating

Rough surfaces composed of discrete but relatively uniform nanoparticles were prepared from a lightly sulfonated polystyrene ionomer by spin coating from tetrahydrofuran (THF) or a THF/methanol mixture onto a silica surface. The particle morphology is consistent with the spinodal decomposition of the film surface occurring during spin coating. The particles are well wetted to the silica, and if heated for a long time above the ionomer's glass-transition temperature, the particles flow and coalesce into a smooth, homogeneous film.

Viscous spin exchange torque on precessional magnetization in (LaMnO3)2n/(SrMnO3)n superlattices

Photoinduced magnetization dynamics is investigated in chemically ordered (LaMnO3)2n/(SrMnO3)n superlattices using the time-resolved magneto-optic Kerr effect. A monotonic frequency-field dependence is observed for the n=1 superlattice, indicating a single spin population consistent with a homogeneous hole distribution. In contrast, for n> or =2 superlattices, a large precession frequency is observed at low fields indicating the presence of an exchange torque in the dynamic regime. We attribute the emergence of exchange torque to the coupling between two spin populations-viscous and fast spins.