Recombinant human soluble domain of CD39L3 and ticagrelor: cardioprotective effects in experimental myocardial infarction

BACKGROUND AND AIMS

The ecto-nucleoside triphosphate diphosphohydrolases of the CD39 family degrade ATP and ADP into AMP, which is converted into adenosine by the extracellular CD73/ecto-5-nucleotidase. This pathway has been explored in antithrombotic treatments but little in myocardial protection. We have investigated whether the administration of solCD39L3 (AZD3366) confers additional cardioprotection to that of ticagrelor alone in a pre-clinical model of myocardial infarction (MI).

METHODS

Ticagrelor-treated pigs underwent balloon-induced MI (90 min) and, before reperfusion, received intravenously either vehicle, 1 mg/kg AZD3366 or 3 mg/kg AZD3366. All animals received ticagrelor twice daily for 42 days. A non-treated MI group was run as a control. Serial cardiac magnetic resonance (baseline, Day 3 and Day 42 post-MI), light transmittance aggregometry, bleeding time, and histological and molecular analyses were performed.

RESULTS

Ticagrelor reduced oedema formation and infarct size at Day 3 post-MI vs. controls. A 3 mg/kg AZD3366 provided an additional 45% reduction in oedema and infarct size compared with ticagrelor and a 70% reduction vs. controls (P < .05). At Day 42, infarct size declined in all ticagrelor-administered pigs, particularly in 3 mg/kg AZD3366-treated pigs (P < .05). Left ventricular ejection fraction was diminished at Day 3 in placebo pigs and worsened at Day 42, whereas it remained unaltered in ticagrelor ± AZD3366-administered animals. Pigs administered with 3 mg/kg AZD3366 displayed higher left ventricular ejection fraction upon dobutamine stress at Day 3 and minimal dysfunctional segmental contraction at Day 42 (χ2P < .05 vs. all). Cardiac and systemic molecular readouts supported these benefits. Interestingly, AZD3366 abolished ADP-induced light transmittance aggregometry without affecting bleeding time.

CONCLUSIONS

Infusion of AZD3366 on top of ticagrelor leads to enhanced cardioprotection compared with ticagrelor alone.

Recombinant Apyrase (AZD3366) Against Myocardial Reperfusion Injury

PURPOSE

Recombinant apyrase (AZD3366) increases adenosine production and ticagrelor inhibits adenosine reuptake. We investigated whether intravenous AZD3366 before reperfusion reduces myocardial infarct size (IS) and whether AZD3366 and ticagrelor have additive effects.

METHODS

Sprague-Dawley rats underwent 30 min ischemia. At 25 min of ischemia, animals received intravenous AZD3366 or vehicle. Additional animals received intravenous CGS15943 (an adenosine receptor blocker) or intraperitoneal ticagrelor. At 24 h reperfusion, IS was assessed by triphenyltetrazolium chloride. Other rats were subjected to 30 min ischemia followed by 1 h or 24 h reperfusion. Myocardial samples were assessed for adenosine levels, RT-PCR, and immunoblotting.

RESULTS

AZD3366 and ticagrelor reduced IS. The protective effect was blocked by CGS15943. The effect of AZD3366 + ticagrelor was significantly greater than AZD3366. One hour after infarction, myocardial adenosine levels significantly increased with AZD3366, but not with ticagrelor. In contrast, 24 h after infarction, adenosine levels were equally increased by AZD3366 and ticagrelor, and levels were higher in the AZD3366 + ticagrelor group. One hour after reperfusion, AZD3366 and ticagrelor equally attenuated the increase in interleukin-15 (an early inflammatory marker after ischemic cell death) levels, and their combined effects were additive. AZD3366, but not ticagrelor, significantly attenuated the increase in RIP1, RIP3, and P-MLKL (markers of necroptosis) 1 h after reperfusion. AZD3366, but not ticagrelor, significantly attenuated the increase in IL-6 and GSDMD-N (markers of pyroptosis) 1 h after reperfusion. At 24 h of reperfusion, both agents equally attenuated the increase in these markers, and their effects were additive.

CONCLUSIONS

AZD3366 attenuated inflammation, necrosis, necroptosis, and pyroptosis and limited IS. The effects of AZD3366 and ticagrelor were additive.

Administration of a human recombinant apyrase (AZD3366) limits myocardial tissue injury and improves cardiac function in a pig model of STEMI assessed by serial CMR

Background

Mitigating myocardial tissue injury (MTI) remains an unmet clinical need in the reperfusion era. Stimulating adenosine synthesis through the breakdown of adenosine triphosphate (ATP) by apyrase (CD39), an endothelial ADPase, has emerged as a potential new avenue in the reduction of MTI.

Purpose

In this study we examined whether the intravenous administration of a recombinant soluble form of human apyrase (AZD3366) prior to reperfusion limits MTI and improves cardiac function in a pig model of STEMI as assessed by serial cardiac magnetic resonance (CMR) imaging.

Methods

Pigs (n=16) were subjected to STEMI induction (1.5h closed-chest complete LAD coronary balloon occlusion). Immediately prior to reperfusion, pigs were randomized to intravenously receive one single dose of 3 mg/kg AZD3366 (n=8) or vehicle (n=8). Serial-CMR imaging was performed at baseline, 3 days, and 42 days post-MI for the assessment of structural and functional readouts at rest and during dobutamine stress. Light transmittance aggregometry (LTA; challenged by 5, 10 and 20 μM ADP) and ear bleeding time were monitored pre-MI, post-MI and at day 3.

Results

AZD3366 significantly reduced MTI by limiting (around 60%) oedema formation (21.3±6.7 vs. 12.3±6.7 g LV) and infarct size (14.3±6.1 vs. 8.4±3.4 g LV) and preventing microvascular obstruction (2.3±0.9 vs. 0.5±0.5 g LV) at 3 days post-MI, compared to vehicle-administered STEMI pigs (p&lt;0.05). At a functional level, LVEDV and LVESV showed less deterioration in AZD3366 treated animal as compared to vehicle 3 days post-MI (p&lt;0.05) and less numerical decrease of LVEF. Furthermore, AZD3366-treated animals showed no deterioration in LVEF upon dobutamine stress in contrast to vehicle-infused animals, (p&lt;0.05). AZD3366 treatment nearly abolished LTA at all tested ADP doses early post-STEMI, an effect that remained up to 3 days post-infusion but did not affect ear bleeding time at any of the tested time points. No additional effects were seen at 42 days.

Conclusion

Infusion of one single dose of the soluble recombinant apyrase AZD3366 prior to reperfusion exerts cardioprotection by reducing oedema formation, microvascular obstruction and necrosis and improving cardiac performance at rest and after dobutamine stress during the acute post-MI period. Administration of AZD3366 as an adjunctive therapy to standard of care for STEMI patients undergoing primary PCI may reduce myocardial tissue injury.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): AstraZeneca, Gothenburg, Sweden

Helios represses megakaryocyte priming in hematopoietic stem and progenitor cells

Our understanding of cell fate decisions in hematopoietic stem cells is incomplete. Here, we show that the transcription factor Helios is highly expressed in murine hematopoietic stem and progenitor cells (HSPCs), where it is required to suppress the separation of the platelet/megakaryocyte lineage from the HSPC pool. Helios acts mainly in quiescent cells, where it directly represses the megakaryocyte gene expression program in cells as early as the stem cell stage. Helios binding promotes chromatin compaction, notably at the regulatory regions of platelet-specific genes recognized by the Gata2 and Runx1 transcriptional activators, implicated in megakaryocyte priming. Helios null HSPCs are biased toward the megakaryocyte lineage at the expense of the lymphoid and partially resemble cells of aging animals. We propose that Helios acts as a guardian of HSPC pluripotency by continuously repressing the megakaryocyte fate, which in turn allows downstream lymphoid priming to take place. These results highlight the importance of negative and positive priming events in lineage commitment.

Health status and health care utilization after discharge from geriatric in-hospital stay - description of a register-based study

Background

This study is the first part of a register-based research program with the overall aim to increase the knowledge of the health status among geriatric patients and to identify risk factors for readmission in this population. The aim of this study was two-fold: 1) to evaluate the validity of the study cohorts in terms of health care utilization in relation to regional cohorts; 2) to describe the study cohorts in terms of health status and health care utilization after discharge.

Methods

The project consist of two cohorts with data from patient records of geriatric in-hospital stays, health care utilization data from Stockholm Regional Healthcare Data Warehouse 6 months after discharge, socioeconomic data from Statistics Sweden. The 2012 cohort include 6710 patients and the 2016 cohort, 8091 patients; 64% are women, mean age is 84 (SD 8).

Results

Mean days to first visit in primary care was 12 (23) and 10 (19) in the 2012 and 2016 cohort, respectively. Readmissions to hospital was 38% in 2012 and 39% in 2016. The validity of the study cohorts was evaluated by comparing them with regional cohorts. The study cohorts were comparable in most cases but there were some significant differences between the study cohorts and the regional cohorts, especially regarding amount and type of primary care.

Conclusion

The study cohorts seem valid in terms of health care utilization compared to the regional cohorts regarding hospital care, but less so regarding primary care. This will be considered in the analyses and when interpreting data in future studies based on these study cohorts. Future studies will explore factors associated with health status and re-admissions in a population with multi-morbidity and disability.

Reduced mTORC1-signaling in retinal ganglion cells leads to vascular retinopathy

BACKGROUND

The coordinated wiring of neurons, glia and endothelial cells into neurovascular units is critical for central nervous system development. This is best exemplified in the mammalian retina where interneurons, astrocytes and retinal ganglion cells sculpt their vascular environment to meet the metabolic demands of visual function. Identifying the molecular networks that underlie neurovascular unit formation is an important step towards a deeper understanding of nervous system development and function.

RESULTS

Here, we report that cell-to-cell mTORC1-signaling is essential for neurovascular unit formation during mouse retinal development. Using a conditional knockout approach we demonstrate that reduced mTORC1 activity in asymmetrically positioned retinal ganglion cells induces a delay in postnatal vascular network formation in addition to the production of rudimentary and tortuous vessel networks in adult animals. The severity of this vascular phenotype is directly correlated to the degree of mTORC1 down regulation within the neighboring retinal ganglion cell population.

CONCLUSIONS

This study establishes a cell nonautonomous role for mTORC1-signaling during retinal development. These findings contribute to our current understanding of neurovascular unit formation and demonstrate how ganglion cells actively sculpt their local environment to ensure that the retina is perfused with an appropriate supply of oxygen and nutrients.

Prognostic role of serum thymidine kinase 1 kinetics during neoadjuvant chemotherapy for early breast cancer

Background

Emerging data support the use of thymidine kinase 1 (TK1) activity as a prognostic marker and for monitoring of response in breast cancer (BC). The long-term prognostic value of TK1 kinetics during neoadjuvant chemotherapy is unclear, which this study aimed to elucidate.

Methods

Material from patients enrolled to the single-arm prospective PROMIX trial of neoadjuvant epirubicin, docetaxel and bevacizumab for early BC was used. Ki67 in baseline biopsies was assessed both centrally and by automated digital imaging analysis. TK1 activity was measured from blood samples obtained at baseline and following two cycles of chemotherapy. The associations of TK1 and its kinetics as well as Ki67 with event-free survival and overall survival (OS) were evaluated using multivariable Cox regression models.

Results

Central Ki67 counting had excellent correlation with the results of digital image analysis (r = 0.814), but not with the diagnostic samples (r = 0.234), while it was independently prognostic for worse OS [adjusted hazard ratio (HR_adj) = 2.72, 95% confidence interval (CI) 1.19-6.21, P = 0.02]. Greater increase in TK1 activity after two cycles of chemotherapy resulted in improved event-free survival (HR_adj = 0.50, 95% CI 0.26-0.97, P = 0.04) and OS (HR_adj = 0.46, 95% CI 0.95, P = 0.04). There was significant interaction between the prognostic value of TK1 kinetics and Ki67 (p_interaction 0.04).

Conclusion

Serial measurement of serum TK1 activity during neoadjuvant chemotherapy provides long-term prognostic information in BC patients. The ease of obtaining serial samples for TK1 assessment motivates further evaluation in larger studies.

•

This is a correlative analysis of a prospective phase II study on neoadjuvant chemotherapy for breast cancer.

•

Serial measurement of serum TK1 activity during treatment provides independent long-term prognostic information.

•

We demonstrate the validity and clinical utility of both central and automated image analysis-based Ki67 assessment.

•

Finally, we explore the biologic correlations between TK1 and Ki67.

Human Embryonic Stem Cell-derived Neural Crest Cells Promote Sprouting and Motor Recovery Following Spinal Cord Injury in Adult Rats

Spinal cord injury results in irreversible tissue damage and permanent sensorimotor impairment. The development of novel therapeutic strategies that improve the life quality of affected individuals is therefore of paramount importance. Cell transplantation is a promising approach for spinal cord injury treatment and the present study assesses the efficacy of human embryonic stem cell–derived neural crest cells as preclinical cell-based therapy candidates. The differentiated neural crest cells exhibited characteristic molecular signatures and produced a range of biologically active trophic factors that stimulated in vitro neurite outgrowth of rat primary dorsal root ganglia neurons. Transplantation of the neural crest cells into both acute and chronic rat cervical spinal cord injury models promoted remodeling of descending raphespinal projections and contributed to the partial recovery of forelimb motor function. The results achieved in this proof-of-concept study demonstrates that human embryonic stem cell–derived neural crest cells warrant further investigation as cell-based therapy candidates for the treatment of spinal cord injury.

Local retinoic acid signaling directs emergence of the extraocular muscle functional unit

Coordinated development of muscles, tendons, and their attachment sites ensures emergence of functional musculoskeletal units that are adapted to diverse anatomical demands among different species. How these different tissues are patterned and functionally assembled during embryogenesis is poorly understood. Here, we investigated the morphogenesis of extraocular muscles (EOMs), an evolutionary conserved cranial muscle group that is crucial for the coordinated movement of the eyeballs and for visual acuity. By means of lineage analysis, we redefined the cellular origins of periocular connective tissues interacting with the EOMs, which do not arise exclusively from neural crest mesenchyme as previously thought. Using 3D imaging approaches, we established an integrative blueprint for the EOM functional unit. By doing so, we identified a developmental time window in which individual EOMs emerge from a unique muscle anlage and establish insertions in the sclera, which sets these muscles apart from classical muscle-to-bone type of insertions. Further, we demonstrate that the eyeballs are a source of diffusible all-trans retinoic acid (ATRA) that allow their targeting by the EOMs in a temporal and dose-dependent manner. Using genetically modified mice and inhibitor treatments, we find that endogenous local variations in the concentration of retinoids contribute to the establishment of tendon condensations and attachment sites that precede the initiation of muscle patterning. Collectively, our results highlight how global and site-specific programs are deployed for the assembly of muscle functional units with precise definition of muscle shapes and topographical wiring of their tendon attachments.

Administration of a soluble ADPase, AZD3366, on top of ticagrelor confers additional cardioprotective benefits to that of ticagrelor alone

Background

Preclinical and pilot human studies suggest platelet-independent cardioprotective effects of ticagrelor most likely due to its ability to block cellular uptake of adenosine. Adenosine is a potent endogenous protective molecule, concentrations of which locally rise as a response to ischemia because of the breakdown of extracellular ATP by an endothelial ADPase (apyrase, CD39) to AMP that is subsequently converted to adenosine by CD73.

Purpose

In the present study we used cardiac magnetic resonance (CMR) imaging in a pig model of myocardial infarction (MI) to examine whether administration of a recombinant soluble form of ADPase, AZD3366 (APT102), confers additional benefits to that of ticagrelor alone in terms of reduced infarct size and improved heart function.

Methods

Pigs (n=20) were administered an oral loading dose of ticagrelor (180mg) and 2h later subjected to MI induction (1.5h closed-chest LAD coronary balloon occlusion). Prior to reperfusion, pigs were randomized to intravenously receive 1) vehicle (n=5); 2) 1mg/kg AZD3366 (n=5); or 3) 3mg/kg AZD3366 (n=5). After reperfusion all pigs were administered ticagrelor (90mg/bid) for 42 days. A non-treated control-MI group (n=5) was run for comparative purposes. Serial-CMR imaging was performed at baseline and 3 and 42 days post-MI for global and regional structural and functional assessments. Light transmittance aggregometry (LTA; challenged by 5, 10 and 20μM ADP) and ear bleeding time were monitored throughout the study.

Results

Ticagrelor significantly reduced edema formation (29.8±1.9 vs. 13.1±0.9%LV) and limited infarct size (17.7±1.5 vs. 8.2±1.2%LV) at 3 days post-MI as compared to control-MI pigs (p&lt;0.05), an effect that persisted up to 42 days. Infusion of 1mg/kg AZD3366 showed a clear signal towards further prevention of myocardial damage that reached significance at doses of 3mg/kg (additional reduction of 35% and 52% in edema and infarct size, respectively, as compared to pigs treated with ticagrelor alone; p&lt;0.05). Left ventricular ejection fraction was higher in all ticagrelor-treated pigs at 3 and 42 days post-MI vs. control (p&lt;0.05). Yet, regional analysis of the jeopardized myocardium revealed that pigs administered 3mg/kg AZD3366 on top of ticagrelor presented minimal dysfunctional segmental contraction as compared to the mild hypokinetic and akinetic disturbances observed in ticagrelor-alone and control-MI pigs (χ2 p&lt;0.05 vs. all). Ticagrelor inhibited ADP-induced platelet aggregation by 30% and addition of AZD3366 acutely abolished (90% inhibition) LTA at all tested ADP doses, an effect remaining significant up to 3 days post-infusion. Ear bleeding time was not affected by AZD3366.

Conclusion

Infusion of a soluble recombinant ADPase (AZD3366) on top of ticagrelor leads to a greater cardioprotection as compared to ticagrelor alone. Co-administration of both drugs in AMI patients undergoing revascularization deserves to be investigated.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Ministerio de Ciencia, Innovaciόn y Universidades / Instituto de Salud Carlos III

Fluconazole Therapy for Fungal Peritonitis in Continuous Ambulatory Peritoneal Dialysis (CAPD): A Case Report

Fluconazole proved effective in treating fungal peritonitis caused by Trichosporon cutaneum. Fluconazole seems to offer several advantages over other antifungal drugs in the treatment of fungal peritonitis in continuous ambulatory peritoneal dialysis (CAPD) patients.

P2Y12 antagonists and cardiac repair post-myocardial infarction: global and regional heart function analysis and molecular assessments in pigs

Aims

P2Y12 antagonists are the standard in antiplatelet therapy but their potential effects on functional myocardial recovery and cardioprotection post-myocardial infarction (MI) are unknown. We investigated in a preclinical model of MI whether ticagrelor and clopidogrel differently affect cardiac repair post-MI.

Methods and results

Pigs either received: (i) clopidogrel (600 mg; 75 mg/qd); (ii) ticagrelor (180 mg; 90 mg/bid); and (iii) placebo control. MI was induced by mid-left anterior descending coronary artery balloon occlusion (60 min) and animals received the maintenance doses for the following 42 days. Serial cardiac magnetic resonance was performed at Day 3 and Day 42 for the assessment of global and regional cardiac parameters. We determined cardiac AMP-activated protein kinase (AMPK), Akt/PKB, aquaporin-4, vascular density, and fibrosis. In comparison to controls, both P2Y12 antagonists limited infarct expansion at Day 3, although ticagrelor induced a further 5% reduction (P < 0.05 vs. clopidogrel) whereas oedema was only reduced by ticagrelor (≈23% P < 0.05). Scar size decreased at Day 42 in ticagrelor-treated pigs vs. controls but not in clopidogrel-treated pigs. Left ventricular ejection fraction was higher 3 days post-MI in ticagrelor-treated pigs and persisted up to Day 42 (P < 0.05 vs. post-MI). Regional analysis revealed that control and clopidogrel-treated pigs had severe and extensive wall motion abnormalities in the jeopardized myocardium and a reduced myocardial viability that was not as evident in ticagrelor-treated pigs (χ2P < 0.05 vs. ticagrelor). Only ticagrelor enhanced myocardial AMPK and Akt/PKB activation and reduced aquaporin-4 levels (P < 0.05 vs. control and clopidogrel). No differences were observed in vessel density and fibrosis markers among groups.

Conclusions

Ticagrelor is more efficient than clopidogrel in attenuating myocardial structural and functional alterations post-MI and in improving cardiac healing. These benefits are associated with persistent AMPK and Akt/PKB activation.

Reduced mTORC1-signalling in retinal progenitor cells leads to visual pathway dysfunction

Development of the vertebrate central nervous system involves the co-ordinated differentiation of progenitor cells and the establishment of functional neural networks. This neurogenic process is driven by both intracellular and extracellular cues that converge on the mammalian target of rapamycin complex 1 (mTORC1). Here we demonstrate that mTORC1-signalling mediates multi-faceted roles during central nervous system development using the mouse retina as a model system. Downregulation of mTORC1-signalling in retinal progenitor cells by conditional ablation of Rptor leads to proliferation deficits and an over-production of retinal ganglion cells during embryonic development. In contrast, reduced mTORC1-signalling in postnatal animals leads to temporal deviations in programmed cell death and the consequent production of asymmetric retinal ganglion cell mosaics and associated loss of axonal termination topographies in the dorsal lateral geniculate nucleus of adult mice. In combination these developmental defects induce visually mediated behavioural deficits. These collective observations demonstrate that mTORC1-signalling mediates critical roles during visual pathway development and function.

Summary: Conditional deletion of Rptor in retinal progenitor cells demonstrates that mTORC1-signalling is critical for visual pathway development and function.

Abstract P1-16-09: Low-dose chemotherapy (CT) + bevacizumab (Bev) combined with unchanged endocrine treatment (ET) in patients with recurrent luminal breast cancer progressing during ET – Effect determined by standard imaging and changes in ctDNA and CTC during treatment

Background: Several mechanisms are involved in the development of endocrine resistance, such as mutations in the ESR1, PIK3CA, and TP53 genes and/or up-regulation of tyrosine kinase receptors such as the endothelial growth factor (VEGF) receptor. Preclinical data have revealed that sensitivity to endocrine therapy may be restored if these pathways are blocked.

Aims: To investigate the progression-free survival (PFS), overall response rate (ORR), and the toxicity of the study treatment. To use circulating tumor cells (CTC) and circulating tumor DNA (ct-DNA) at base-line and during treatment for next generation sequencing (NGS) to investigate whether changes in tumor mutations or in levels of CTC/ct-DNA correlate to treatment efficacy.

Patients and methods: Thirty-two patients aged 46-77 years with confirmed advanced breast cancer (ABC) progressing during ET were included. Treatment consisted of unchanged ET with the addition of cyclophosphamide 50mg x 1 and capecitabine 500mg x 3 daily + bevacizumab 15mg/kg iv. every third week (q21). Blood samples for analysis of CTC and ctDNA were collected at base-line, after the 1st and 2nd course, and at progression. CTC were isolated by use of an immune-magnetic selection (ADNA-test) and sequenced by NGS. ctDNA were analysed by the SiMSen-Seq (Simple Multiplexed PCR-based barcoding of DNA for Sensitive mutation detection using Sequencing) that allows mutant frequencies &lt; 0.1% to be detected.

Results: One patient did not start treatment and 2 were not evaluable. Palliative chemotherapy (1-2 lines) had been delivered before inclusion to 28% and &gt; 1 line of palliative ET to 58% of the patients. A total of 72% (n=21) of the patients had visceral disease (of whom 7 had liver metastases), and 28% (n=8) patients bone-only disease. Median PFS was 9.1 months (range 2.1-59.3 months). Best responses were: 1 patient (3%) received complete remission; 7 patients (24%) partial response; 16 patients (55%) SD (of whom 12 had CB, defined as SD &gt; 24 weeks), and 5 (17%) had progressive disease. The ORR (defined as CR, PR, or CB) was 69%. The most common toxicity was hypertension (62%), that resulted in termination in 2 patients, and 1 patient stopped treatment due to thrombocytopenia. Other side-effects were proteinuria grade 1-3 (24%); hand-foot-syndrome grade 1-2 (45%); mucositis grade 1 (14%); nausea grade 1 (14%) and diarrhea grade 1-3 (10%). CTC was isolated in 12 patients (37%). Three out of the 5 patients with PD at 12 weeks had detectable CTCs at base-line. Base-line ESR1, PIK3CA and TP53 mutations were found in CTC from 2 patients (17%), 7 patients (58%), and 5 patients (42%), respectively, but did not correlate to response.

Conclusion: The treatment was well tolerated with an ORR of 69%, which is considered very good in this setting. CTCs were only isolated in 37% of the patients which is comparable to previously reported results in metastatic luminal breast cancer and thus not a feasible method for monitoring treatment effect. Results on levels of consecutive ctDNA, as well as mutation pattern in relation treatment effect will be presented.

Citation Format: Linderholm BK, Ekholm M, Wännstig A-K, Lundstedt D, Carlsson L, Tzikas A-K, Svensson J, Kristiansson H, Filges S, Ståhlberg A. Low-dose chemotherapy (CT) + bevacizumab (Bev) combined with unchanged endocrine treatment (ET) in patients with recurrent luminal breast cancer progressing during ET – Effect determined by standard imaging and changes in ctDNA and CTC during treatment [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-16-09.

Abstract P6-17-24: Use of subcutaneous and intravenous trastuzumab: Real-world experience from three hospitals in Sweden

Background

Trastuzumab (H; F. Hoffmann-La Roche Ltd, Basel, CH) reduces recurrence and improves survival in patients (pts) with HER2-positive early breast cancer (EBC). Two formulations which are noninferior in terms of pathologic complete response and serum trough concentration (Ismael et al. Lancet Oncol 2012) are available, for intravenous (IV) and subcutaneous (SC) administration. A randomized open-label study, PrefHer, reported compelling pt preference for H SC (Pivot et al. Lancet Oncol 2013; Ann Oncol 2014), and a prospective observational study reported less societal cost and pt time associated with H SC vs H IV in Sweden (Olofsson et al. Breast 2016), which may allow for earlier release of pts from hospital. To assess how this may translate to actual practice, we aimed to describe H SC and H IV use in a real-world setting and investigated a potential switch from one formulation to the other in the real world.

Methods

This observational, retrospective, longitudinal cohort study evaluated electronic medical records of adult female pts with a first incident diagnosis of EBC (neoadjuvant or adjuvant settings) and first use of H from 01/01/10–04/24/18 in three mid-size hospitals in Sweden (Sundsvall, Eskilstuna, and Kalmar). Data from first H administration (index date) until last recorded visit up to the day before metastasis (if any) were analyzed. Combination anticancer treatment was defined as any drug recorded from index date to index date +28 days. A switch between formulations was defined as any H administration using a formulation different from that given at the index date.

Results

Four hundred twenty-one pts received initial H (median age 60.2 years, range 23.3–88.5). Of these, 260 (61.8%) started treatment with H SC and 161 (38.2%) with H IV. After H SC was introduced in Nov 2013, use of H SC as the initial formulation increased from 72.7% in 2014 to 100% in 2017 (Table). Both H SC and H IV were mostly initiated with a combination IV chemotherapy e.g., a taxane (65.8% vs 74.5%, respectively). Some combination pertuzumab (F. Hoffmann-La Roche Ltd) was observed (2.3% vs 1.9%). Since 2013, 40 of 63 pts (63.5%) switched from initial H IV to H SC; ten (25.0%) switched back to H IV. Four of 260 pts (1.5%) switched from H SC to H IV; three (75.0%) switched back to H SC.

 H SC n=260H IV n=161Calendar year of the index date, n (%/year)  2010021 (100)2011026 (100)2012051 (100)20131 (3.7)26 (96.3)201448 (72.7)18 (27.3)201555 (79.7)14 (20.3)201677 (93.9)5 (6.1)201772 (100)0 (0)20187 (100)0 (0)Combination anticancer treatment, n (% of all)  Taxanes171 (65.8)120 (74.5)Anthracyclines5 (1.9)1 (0.6)Pertuzumab6 (2.3)3 (1.9)Other (platinum salts, metabolites, other cytotoxic/cytostatic agents)11 (4.2)4 (2.5)

Conclusion

H SC quickly became the prevailing (practically exclusive) formulation for treatment of pts with HER2-positive EBC. Furthermore, most pts who started on H IV switched to H SC, while a minority switched from H SC to H IV. Most pts also received similar combination IV treatment (e.g., pertuzumab or chemotherapy) regardless of H formulation. Results are in line with pt preference for H SC in the PrefHer study, and the body of evidence that oncology units switch to SC formulations of biologics as an integral part of routine care.

Citation Format: Valachis A, Carlsson L, Sundqvist M, Li B, Chiesa F, Uhde M, Sanglier T. Use of subcutaneous and intravenous trastuzumab: Real-world experience from three hospitals in Sweden [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-17-24.

Rapid Production of Human VEGF-A following Intradermal Injection of Modified VEGF-A mRNA Demonstrated by Cutaneous Microdialysis in the Rabbit and Pig In Vivo

Chemically modified mRNA is a novel, highly efficient, biocompatible modality for therapeutic protein expression that may overcome the challenges and safety concerns with current gene therapy strategies. We explored the efficiency of intradermally injected modified VEGF-A165 mRNA (VEGF-A mRNA) formulated in a biocompatible citrate/saline buffer to locally produce human VEGF-A165 protein. Rabbits (n=4) and minipigs (n=3) were implanted with subcutaneous microdialysis probes close to the injection sites and interstitial-fluid samples and skin biopsies were analysed for production of VEGF-A protein over time for up to 8 hours. Three to 4 hours after the intradermal injection of VEGF-A mRNA, detectable levels of human VEGF-A protein were seen in the microdialysis eluates in both species. In the pig, the VEGF-A concentrations increased dose-dependently reaching a maximum 6 hours after dosing (62.7±28.4, 357.6±240.6, and 746.3±210.2 pg/mL following injection of 24, 120, and 600 μg VEGF-A mRNA, respectively). Likewise, in tissue biopsies harvested at study end (8 hours after VEGF-A mRNA injection), the content of VEGF-A protein increased dose-dependently. In contrast, VEGF-A protein was not detected in eluates originating from sites injected with citrate/saline vehicle. It is concluded that intradermal injection of VEGF-A mRNA is associated with a rapid and local production of VEGF-A protein. Considering the pro-angiogenic effect of VEGF-A, VEGF-A mRNA may hold promise for regenerative treatment of patients with diabetic wounds and ischemic cardiovascular disease.

Biocompatible, Purified VEGF-A mRNA Improves Cardiac Function after Intracardiac Injection 1 Week Post-myocardial Infarction in Swine

mRNA can direct dose-dependent protein expression in cardiac muscle without genome integration, but to date has not been shown to improve cardiac function in a safe, clinically applicable way. Herein, we report that a purified and optimized mRNA in a biocompatible citrate-saline formulation is tissue specific, long acting, and does not stimulate an immune response. In small- and large-animal, permanent occlusion myocardial infarction models, VEGF-A 165 mRNA improves systolic ventricular function and limits myocardial damage. Following a single administration a week post-infarction in mini pigs, left ventricular ejection fraction, inotropy, and ventricular compliance improved, border zone arteriolar and capillary density increased, and myocardial fibrosis decreased at 2 months post-treatment. Purified VEGF-A mRNA establishes the feasibility of improving cardiac function in the sub-acute therapeutic window and may represent a new class of therapies for ischemic injury.

Regenerative effects of human embryonic stem cell-derived neural crest cells for treatment of peripheral nerve injury

Surgical intervention is the current gold standard treatment following peripheral nerve injury. However, this approach has limitations, and full recovery of both motor and sensory modalities often remains incomplete. The development of artificial nerve grafts that either complement or replace current surgical procedures is therefore of paramount importance. An essential component of artificial grafts is biodegradable conduits and transplanted cells that provide trophic support during the regenerative process. Neural crest cells are promising support cell candidates because they are the parent population to many peripheral nervous system lineages. In this study, neural crest cells were differentiated from human embryonic stem cells. The differentiated cells exhibited typical stellate morphology and protein expression signatures that were comparable with native neural crest. Conditioned media harvested from the differentiated cells contained a range of biologically active trophic factors and was able to stimulate in vitro neurite outgrowth. Differentiated neural crest cells were seeded into a biodegradable nerve conduit, and their regeneration potential was assessed in a rat sciatic nerve injury model. A robust regeneration front was observed across the entire width of the conduit seeded with the differentiated neural crest cells. Moreover, the up-regulation of several regeneration-related genes was observed within the dorsal root ganglion and spinal cord segments harvested from transplanted animals. Our results demonstrate that the differentiated neural crest cells are biologically active and provide trophic support to stimulate peripheral nerve regeneration. Differentiated neural crest cells are therefore promising supporting cell candidates to aid in peripheral nerve repair.

Life situation 5 years after subarachnoid haemorrhage

OBJECTIVES

Subarachnoid haemorrhage (SAH) has high mortality and morbidity among survivors. SAH mainly affects young people and may result in long-term disabilities such as decreased Health-related Quality of Life (HRQoL), mental health and cognitive function. The aim of this study was to investigate the life situation 5 years after a SAH including physical/emotional status, participation and HRQoL.

MATERIALS & METHODS

In this cross-sectional descriptive study, a mail survey was sent to all persons treated at a neurosurgery unit in Gothenburg, Sweden, for non-traumatic SAH in 2009-2010, approximately 5 years post-SAH. The survey included questions regarding HRQoL; EuroQol 5-Dimensions (EQ-5D), the impact of the SAH; Stroke Impact Scale (SIS), Occupational Gaps Questionnaire and participation in society; Impact of Participation and Autonomy (IPA).

RESULTS

Forty-two 5 year survivors were sent the survey, of whom 26 (62%) responded (59 years old, range 33-85). The participants had generally low HRQoL and scored low in the domain of anxiety and depression. Many reported problems with emotions, fatigue, memory and executive function, but few problems with physical condition. However, nearly all participants reported to have an acceptable level of participation and 64% were independent in their daily life.

CONCLUSIONS

In this 5-year follow-up after SAH, the participants reported to have a greater number of hidden disabilities compared to physical problems, whereas most had acceptable participation in society. A yearly follow-up after a SAH could be suggested aiming to improving the cognitive and mental health.

A novel mouse model of anterior segment dysgenesis (ASD): conditional deletion of Tsc1 disrupts ciliary body and iris development

Development of the cornea, lens, ciliary body and iris within the anterior segment of the eye involves coordinated interaction between cells originating from the ciliary margin of the optic cup, the overlying periocular mesenchyme and the lens epithelium. Anterior segment dysgenesis (ASD) encompasses a spectrum of developmental syndromes that affect these anterior segment tissues. ASD conditions arise as a result of dominantly inherited genetic mutations and result in both ocular-specific and systemic forms of dysgenesis that are best exemplified by aniridia and Axenfeld-Rieger syndrome, respectively. Extensive clinical overlap in disease presentation amongst ASD syndromes creates challenges for correct diagnosis and classification. The use of animal models has therefore proved to be a robust approach for unravelling this complex genotypic and phenotypic heterogeneity. However, despite these successes, it is clear that additional genes that underlie several ASD syndromes remain unidentified. Here, we report the characterisation of a novel mouse model of ASD. Conditional deletion of Tsc1 during eye development leads to a premature upregulation of mTORC1 activity within the ciliary margin, periocular mesenchyme and lens epithelium. This aberrant mTORC1 signalling within the ciliary margin in particular leads to a reduction in the number of cells that express Pax6, Bmp4 and Msx1 Sustained mTORC1 signalling also induces a decrease in ciliary margin progenitor cell proliferation and a consequent failure of ciliary body and iris development in postnatal animals. Our study therefore identifies Tsc1 as a novel candidate ASD gene. Furthermore, the Tsc1-ablated mouse model also provides a valuable resource for future studies concerning the molecular mechanisms underlying ASD and acts as a platform for evaluating therapeutic approaches for the treatment of visual disorders.

A low-carbohydrate high-fat diet decreases lean mass and impairs cardiac function in pair-fed female C57BL/6J mice

Background

Excess body fat is a major health issue and a risk factor for the development of numerous chronic diseases. Low-carbohydrate diets like the Atkins Diet are popular for rapid weight loss, but the long-term consequences remain the subject of debate. The Scandinavian low-carbohydrate high-fat (LCHF) diet, which has been popular in Scandinavian countries for about a decade, has very low carbohydrate content (~5 E %) but is rich in fat and includes a high proportion of saturated fatty acids. Here we investigated the metabolic and physiological consequences of a diet with a macronutrient composition similar to the Scandinavian LCHF diet and its effects on the organs, tissues, and metabolism of weight stable mice.

Methods

Female C57BL/6J mice were iso-energetically pair-fed for 4 weeks with standard chow or a LCHF diet. We measured body composition using echo MRI and the aerobic capacity before and after 2 and 4 weeks on diet. Cardiac function was assessed by echocardiography before and after 4 weeks on diet. The metabolic rate was measured by indirect calorimetry the fourth week of the diet. Mice were sacrificed after 4 weeks and the organ weight, triglyceride levels, and blood chemistry were analyzed, and the expression of key ketogenic, metabolic, hormonal, and inflammation genes were measured in the heart, liver, and adipose tissue depots of the mice using real-time PCR.

Results

The increase in body weight of mice fed a LCHF diet was similar to that in controls. However, while control mice maintained their body composition throughout the study, LCHF mice gained fat mass at the expense of lean mass after 2 weeks. The LCHF diet increased cardiac triglyceride content, impaired cardiac function, and reduced aerobic capacity. It also induced pronounced alterations in gene expression and substrate metabolism, indicating a unique metabolic state.

Conclusions

Pair-fed mice eating LCHF increased their percentage of body fat at the expense of lean mass already after 2 weeks, and after 4 weeks the function of the heart deteriorated. These findings highlight the urgent need to investigate the effects of a LCHF diet on health parameters in humans.

Protective Effects of Ticagrelor on Myocardial Injury After Infarction

BACKGROUND

The P2Y₁₂ receptor antagonist ticagrelor has been shown to be clinically superior to clopidogrel. Although the underlying mechanisms remain elusive, ticagrelor may exert off-target effects through adenosine-related mechanisms. We aimed to investigate whether ticagrelor reduces myocardial injury to a greater extent than clopidogrel after myocardial infarction (MI) at a similar level of platelet inhibition and to determine the underlying mechanisms.

METHODS

Pigs received the following before MI induction: (1) placebo-control; (2) a loading dose of clopidogrel (600 mg); (3) a loading dose of ticagrelor (180 mg); or (4) a loading dose of ticagrelor followed by an adenosine A1/A2-receptor antagonist [8-(p-sulfophenyl)theophylline, 4 mg/kg intravenous] to determine the potential contribution of adenosine in ticagrelor-related cardioprotection. Animals received the corresponding maintenance doses of the antiplatelet agents during the following 24 hours and underwent 3T-cardiac MRI analysis. Platelet inhibition was monitored by ADP-induced platelet aggregation. In the myocardium, we assessed the expression and activation of proteins known to modulate edema formation, including aquaporin-4 and AMP-activated protein kinase and its downstream effectors CD36 and endothelial nitric oxide synthase and cyclooxygenase-2 activity.

RESULTS

Clopidogrel and ticagrelor exerted a high and consistent antiplatelet effect (68.2% and 62.2% of platelet inhibition, respectively, on challenge with 20 μmol/L ADP) that persisted up to 24 hours post-MI (P<0.05). All groups showed comparable myocardial area-at-risk and cardiac worsening after MI induction. 3T-Cardiac MRI analysis revealed that clopidogrel- and ticagrelor-treated animals had a significantly smaller extent of MI than placebo-control animals (15.7 g left ventricle and 12.0 g left ventricle versus 22.8 g left ventricle, respectively). Yet, ticagrelor reduced infarct size to a significantly greater extent than clopidogrel (further 23.5% reduction; P=0.0026), an effect supported by troponin-I assessment and histopathologic analysis (P=0.0021). Furthermore, in comparison with clopidogrel, ticagrelor significantly diminished myocardial edema by 24.5% (P=0.004), which correlated with infarct mass (r=0.73; P<0.001). 8-(p-Sulfophenyl)theophylline administration abolished the cardioprotective effects of ticagrelor over clopidogrel. At a molecular level, aquaporin-4 expression decreased and the expression and activation of AMP-activated protein kinase signaling and cyclooxygenase-2 increased in the ischemic myocardium of ticagrelor- versus clopidogrel-treated animals (P<0.05). These protein changes were not observed in those animals administered the adenosine receptor blocker 8-(p-sulfophenyl)theophylline.

CONCLUSIONS

Ticagrelor, beyond its antiplatelet efficacy, exerts cardioprotective effects by reducing necrotic injury and edema formation via adenosine-dependent mechanisms.

A novel mouse model of tuberous sclerosis complex (TSC): eye-specific Tsc1-ablation disrupts visual-pathway development

Tuberous sclerosis complex (TSC) is an autosomal dominant syndrome that is best characterised by neurodevelopmental deficits and the presence of benign tumours (called hamartomas) in affected organs. This multi-organ disorder results from inactivating point mutations in either the TSC1 or the TSC2 genes and consequent activation of the canonical mammalian target of rapamycin complex 1 signalling (mTORC1) pathway. Because lesions to the eye are central to TSC diagnosis, we report here the generation and characterisation of the first eye-specific TSC mouse model. We demonstrate that conditional ablation of Tsc1 in eye-committed progenitor cells leads to the accelerated differentiation and subsequent ectopic radial migration of retinal ganglion cells. This results in an increase in retinal ganglion cell apoptosis and consequent regionalised axonal loss within the optic nerve and topographical changes to the contra- and ipsilateral input within the dorsal lateral geniculate nucleus. Eyes from adult mice exhibit aberrant retinal architecture and display all the classic neuropathological hallmarks of TSC, including an increase in organ and cell size, ring heterotopias, hamartomas with retinal detachment, and lamination defects. Our results provide the first major insight into the molecular etiology of TSC within the developing eye and demonstrate a pivotal role for Tsc1 in regulating various aspects of visual-pathway development. Our novel mouse model therefore provides a valuable resource for future studies concerning the molecular mechanisms underlying TSC and also as a platform to evaluate new therapeutic approaches for the treatment of this multi-organ disorder.

Editors' choice: Conditional deletion of Tsc1 in the eye results in hamartoma formation and defects in retinal ganglion cell development – a novel mouse model providing insights into visual pathway involvement in TSC.

Molecular subtype and tumor characteristics of breast cancer metastases as assessed by gene expression significantly influence patient post-relapse survival

BACKGROUND

We and others have recently shown that tumor characteristics are altered throughout tumor progression. These findings emphasize the need for re-examination of tumor characteristics at relapse and have led to recommendations from ESMO and the Swedish Breast Cancer group. Here, we aim to determine whether tumor characteristics and molecular subtypes in breast cancer metastases confer clinically relevant prognostic information for patients.

PATIENTS AND METHODS

The translational aspect of the Swedish multicenter randomized trial called TEX included 111 patients with at least one biopsy from a morphologically confirmed locoregional or distant breast cancer metastasis diagnosed from December 2002 until June 2007. All patients had detailed clinical information, complete follow-up, and metastasis gene expression information (Affymetrix array GPL10379). We assessed the previously published gene expression modules describing biological processes [proliferation, apoptosis, human epidermal receptor 2 (HER2) and estrogen (ER) signaling, tumor invasion, immune response, and angiogenesis] and pathways (Ras, MAPK, PTEN, AKT-MTOR, PI3KCA, IGF1, Src, Myc, E2F3, and β-catenin) and the intrinsic subtypes (PAM50). Furthermore, by contrasting genes expressed in the metastases in relation to survival, we derived a poor metastasis survival signature.

RESULTS

A significant reduction in post-relapse breast cancer-specific survival was associated with low-ER receptor signaling and apoptosis gene module scores, and high AKT-MTOR, Ras, and β-catenin module scores. Similarly, intrinsic subtyping of the metastases provided statistically significant post-relapse survival information with the worst survival outcome in the basal-like [hazard ratio (HR) 3.7; 95% confidence interval (CI) 1.3-10.9] and HER2-enriched (HR 4.4; 95% CI 1.5-12.8) subtypes compared with the luminal A subtype. Overall, 25% of the metastases were basal-like, 32% HER2-enriched, 10% luminal A, 28% luminal B, and 5% normal-like.

CONCLUSIONS

We show that tumor characteristics and molecular subtypes of breast cancer metastases significantly influence post-relapse patient survival, emphasizing that molecular investigations at relapse provide prognostic and clinically relevant information. CLINICALTRIALS.GOV: This is the translational part of the Swedish multicenter and randomized trial TEX, clinicaltrials.gov identifier nct01433614 (http://www.clinicaltrials.gov/ct2/show/nct01433614).

Is the acetylcholine-regulated inwardly rectifying potassium current a viable antiarrhythmic target? Translational discrepancies of AZD2927 and A7071 in dogs and humans

AIMS

We aimed at examining the acetylcholine-dependent inward-rectifier current (IKAch) as a target for the management of atrial fibrillation (AF).

METHODS AND RESULTS

The investigative agents AZD2927 and A7071 concentration-dependently blocked IKACh in vitro with minimal off-target activity. In anaesthetized dogs (n = 17) subjected to 8 weeks of rapid atrial pacing (RAP), the left atrial effective refractory period (LAERP) was maximally increased by 50 ± 7.4 and 50 ± 4.8 ms following infusion of AZD2927 and A7071. Ventricular refractoriness and the QT interval were unaltered. During sustained AF, both drugs significantly reduced AF frequency and effectively restored sinus rhythm. AZD2927 successfully restored sinus rhythm at 10/10 conversion attempts and A7071 at 14/14 attempts, whereas saline converted 4/17 episodes only (P<0.001 vs. AZD2927 and A7071). In atrial flutter patients (n = 18) undergoing an invasive investigation, AZD2927 did not change LAERP, the paced QT interval, or ventricular refractoriness when compared with placebo. To address the discrepancy on LAERP by IKACh blockade in man and dog and the hypothesis that atrial electrical remodelling is a prerequisite for IKACh blockade being efficient, six dogs were studied after 8 weeks of RAP followed by sinus rhythm for 4 weeks to reverse electrical remodelling. In these dogs, both AZD2927 and A7071 were as effective in increasing LAERP as in the dogs studied immediately after the 8-week RAP period.

CONCLUSION

Based on the present series of experiments, an important role of IKACh in human atrial electrophysiology, as well as its potential as a viable target for effective management of AF, may be questioned.

Canonical Wnt/β-catenin signalling is essential for optic cup formation

A multitude of signalling pathways are involved in the process of forming an eye. Here we demonstrate that β-catenin is essential for eye development as inactivation of β-catenin prior to cellular specification in the optic vesicle caused anophthalmia in mice. By achieving this early and tissue-specific β-catenin inactivation we find that retinal pigment epithelium (RPE) commitment was blocked and eye development was arrested prior to optic cup formation due to a loss of canonical Wnt signalling in the dorsal optic vesicle. Thus, these results show that Wnt/β-catenin signalling is required earlier and play a more central role in eye development than previous studies have indicated. In our genetic model system a few RPE cells could escape β-catenin inactivation leading to the formation of a small optic rudiment. The optic rudiment contained several neural retinal cell classes surrounded by an RPE. Unlike the RPE cells, the neural retinal cells could be β-catenin-negative revealing that differentiation of the neural retinal cell classes is β-catenin-independent. Moreover, although dorsoventral patterning is initiated in the mutant optic vesicle, the neural retinal cells in the optic rudiment displayed almost exclusively ventral identity. Thus, β-catenin is required for optic cup formation, commitment to RPE cells and maintenance of dorsal identity of the retina.

Angiogenic factors in relation to clinical effect in a phase II trial of weekly paclitaxel

BACKGROUND

Several anticancer agents including paclitaxel have an inhibitory effect on angiogenesis.

AIMS

To compare the overall response rate and time to progression with changes in circulating angiogenic factors during palliative treatment with weekly paclitaxel.

MATERIAL AND METHODS

Patients with metastatic BC, ECOG 0-2, received weekly paclitaxel, concomitant with trastuzumab if HER2+ BC (n = 7). Circulating vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) were determined at base-line and before start of new course.

RESULTS

Fifty-five of 63 included patients were evaluable. The overall response rate including stable disease ≥24 weeks (CR + PD + SD) was obtained in 25 of the evaluable patients (45%). The median time to progression (TTP) was 5.3 months and overall survival (OS) 16.7 months. Patients with triple negative breast cancer (TNBC) showed a trend towards higher base-line VEGF compared with hormone receptor positive or HER2+ tumours and had shorter TTP. Significant differences in VEGF and bFGF levels at 12 weeks were found between patients with longer versus shorter TTP (VEGF: p = 0.046, bFGF: p = 0.005) and between patients gaining versus lacking clinical benefit (VEGF: p = 0.05, bFGF: p = 0.02).

CONCLUSIONS

The clinical utility of circulating VEGF may be a useful tool for monitoring treatment efficacy.

Serum thymidine kinase activity compared with CA 15-3 in locally advanced and metastatic breast cancer within a randomized trial

The primary objective was to estimate serum thymidine kinase 1 (TK1) activity, reflecting total body cell proliferation rate including cancer cell proliferation, in women with loco regional inoperable or metastatic breast cancer participating in a prospective and randomized study. Secondary objectives were to analyze TK1 in relation to progression-free survival (PFS), overall survival (OS), therapy response and other tumour characteristics, including CA 15-3, widely used as a standard serum marker for disease progression. TK1 and CA 15-3 were analysed in 198 serum samples collected prospectively from women included in the randomized TEX trial between December 2002 and June 2007. TK1 activity was determined by the ELISA based DiviTum™ assay, and CA 15-3 analyses was generated with the electrochemiluminescence immunoassay Cobas Elecsys CA 15-3 II. High pre-treatment TK1 activity predicted shorter PFS (10 vs. 15 months p = 0.02) and OS (21 vs. 38 months, p < 0.0001), respectively. After adjustment for age, metastatic site and study treatment TK1 showed a trend as predictor of PFS (p = 0.059) and was an independent prognostic factor for OS, (HR 1.81, 95 % confidence interval (CI) 1.26-2.61, p = 0.001). There was a trend of shortened OS for women with high CA 15-3 (p = 0.054) in univariate analysis, but not after adjustment for the above mentioned covariates. Both TK1 (p = 0.0011) and CA 15-3 (p = 0.0004) predicted response to treatment. There were statistically different distributions of TK1 and CA 15-3 in relation to the site of metastases. TK1 activity measured by DiviTum™ predicted therapy response, PFS and OS in loco regional inoperable or disseminated breast cancer. These results suggest that this factor is a useful serum marker. In the present material, a prognostic value of CA 15-3 could not be proven.

Assessment of ventricular repolarization variability with the DeltaT50 method improves identification of patients with congenital long QT syndromes

BACKGROUND

We analyzed ventricular repolarization variability in genotyped long QT syndrome (LQTS) patients and in healthy volunteers (HV).

METHOD

The deltaT50, that is, the temporal variability of ventricular repolarization at 50% of the T-wave downslope, was analyzed every 15th minute on 175 and 390 Holter electrocardiogram (ECG) recordings from HV and genotyped LQTS patients, respectively. The average deltaT50 and QTcF were calculated in each subject.

RESULTS

DeltaT50 was 2.26 ± 0.71 ms (mean ± SD) in the HV and 5.74 ± 2.30 ms in the LQTS population (P < 0.0001). The sensitivity and specificity of QTcF (cutoff value 450 ms) to discriminate between the LQTS patients and the HV were 51.5% and 98.9%, and for deltaT50 (cutoff value 3 ms) 93.9% and 88.6%, respectively. The combination of both variables improved the diagnosis of the LQTS patients even further. Subgroups of LQTS patients at higher risk of cardiac events (with LQTS3, JLN, QTc > 500 ms or symptoms) had higher deltaT50 than subgroups at lower risk (with LQTS1, QTc < 450 ms or without symptoms). The variation in deltaT50 between day and night was concordant with the risk of symptoms; patients with LQTS1 had higher deltaT50 in the daytime and patients with LQTS3 had higher deltaT50 during the night.

CONCLUSION

DeltaT50 more accurately distinguished between LQTS patients and HV than QTcF and was higher in LQTS patients with a higher risk of cardiac events. DeltaT50 can be used together with QTcF to improve the diagnosis in patients with the LQTS phenotype and tentatively also be of value for risk assessment in such patients.

Lhx2-dependent specification of olfactory sensory neurons is required for successful integration of olfactory, vomeronasal, and GnRH neurons

Inactivation of the LIM-homeodomain 2 gene (Lhx2) results in a severe defect in specification of olfactory sensory neurons (OSNs). However, the ramifications of lack of Lhx2-dependent OSN specification for formation of the primary olfactory pathway have not been addressed, since mutant mice die in utero. We have analyzed prenatal and postnatal consequences of conditionally inactivating Lhx2 selectively in OSNs. A cell-autonomous effect is that OSN axons cannot innervate their target, the olfactory bulb. Moreover, the lack of Lhx2 in OSNs causes unpredicted, non-cell-autonomous phenotypes. First, the olfactory bulb shows pronounced hypoplasia in adults, and the data suggest that innervation by correctly specified OSNs is necessary for adult bulb size and organization. Second, absence of an olfactory nerve in the conditional mutant reveals that the vomeronasal nerve is dependent on olfactory nerve formation. Third, the lack of a proper vomeronasal nerve prevents migration of gonadotropin-releasing hormone (GnRH) cells the whole distance to their final positions in the hypothalamus during embryo development. As adults, the conditional mutants do not pass puberty, and these findings support the view of an exclusive nasal origin of GnRH neurons in the mouse. Thus, Lhx2 in OSNs is required for functional development of three separate systems.

The lhx2 transcription factor controls thalamocortical axonal guidance by specific regulation of robo1 and robo2 receptors

The assembly of neural circuits is dependent upon the generation of specific neuronal subtypes, each subtype displaying unique properties that direct the formation of selective connections with appropriate target cells. Actions of transcription factors in neural progenitors and postmitotic cells are key regulators in this process. LIM-homeodomain transcription factors control crucial aspects of neuronal differentiation, including subtype identity and axon guidance. Nonetheless, their regulation during development is poorly understood and the identity of the downstream molecular effectors of their activity remains largely unknown. Here, we demonstrate that the Lhx2 transcription factor is dynamically regulated in distinct pools of thalamic neurons during the development of thalamocortical connectivity in mice. Indeed, overexpression of Lhx2 provokes defective thalamocortical axon guidance in vivo, while specific conditional deletion of Lhx2 in the thalamus produces topographic defects that alter projections from the medial geniculate nucleus and from the caudal ventrobasal nucleus in particular. Moreover, we demonstrate that Lhx2 influences axon guidance and the topographical sorting of axons by regulating the expression of Robo1 and Robo2 guidance receptors, which are essential for these axons to establish correct connections in the cerebral cortex. Finally, augmenting Robo1 function restores normal axon guidance in Lhx2-overexpressing neurons. By regulating axon guidance receptors, such as Robo1 and Robo2, Lhx2 differentially regulates the axon guidance program of distinct populations of thalamic neurons, thus enabling the establishment of specific neural connections.

Pegylated liposomal doxorubicin as first-line monotherapy in elderly women with locally advanced or metastatic breast cancer: novel treatment predictive factors identified

We investigated the efficacy and safety of single-agent pegylated liposomal doxorubicin (PLD) as first-line treatment for elderly women with advanced breast cancer and evaluated predictive markers for response and toxicity. Twenty-five women ≥ 65 years received 40 mg/m(2) PLD every 28 days. Time to treatment failure (TTF), response rate, time to progression (TTP) and overall survival (OS) was calculated. The ABCB1 single nucleotide polymorphisms (SNP), tumor MRN complex, and TOPOIIα were analyzed. A mean of 7.4 cycles PLD were administered and TTF was 5.5 months and OS 20.6 months. ABCB1 SNPs were found to correlate to both efficacy and toxicity, while tumor expression of the MRN complex and TOPOIIα correlated to TTP. PLD is a safe and effective treatment for elderly breast cancer patients. Also potential predictive markers were identified.

P4-10-02: A Meta-Analysis of the Association of Blood Levels of Vitamin-D and the Risk of Breast Cancer

Background: A considerable body of literature has examined the association of vitamin-D with breast cancer risk and the potential role in its prevention. Geographic studies show higher incidence of breast cancer in patients residing at high latitudes. Other data linking vitamin-D deficiency to breast cancer risk are inconsistent.

Materials and Methods: A literature based meta-analysis was conducted. Odds ratios (OR) for breast cancer based on blood levels of 25-hydroxy or 1,25-hydroxy vitamin-D were computed and pooled. Analysis was conducted separately for studies where blood levels were taken before (group A) or after (group B) breast cancer diagnosis.

Results: Thirteen studies were identified. Nine studies were included in group A and 4 studies included in group B. For group A, there was no significant association between lower vitamin-D levels and breast cancer risk (pooled OR = 1.09, 95% confidence intervals 0.99−1.20, p=0.08). For group B, there was a highly significant association between lower vitamin-D levels and breast cancer (pooled OR = 2.81, 95% confidence intervals 1.70−4.65, p&lt;0.001). The test for interaction between groups was highly significant (p&lt;0.001). When all studies were pooled, the OR was 1.38 (95% confidence intervals 1.13−1.70, p=0.002).

Conclusion: When measured before breast cancer diagnosis, blood levels of vitamin-D are not associated with breast cancer risk. Breast tumors have been shown to differentially express vitamin-D hydroxylase. Therefore, any association of vitamin-D and breast cancer in studies measuring blood levels after breast cancer diagnosis may be confounded by reverse causation bias.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-10-02.

P2-12-07: Pooled Analysis of Outcomes of T1a/bN0, HER2−Amplified Breast Cancer

Background: Breast tumors with HER2 amplification have a worse prognosis than those with normal HER2 expression. This finding is independent of tumor size and other classical prognostic factors used in the adjuvant setting. The prognosis of node negative, sub-centimeter (T1a/bN0) tumors is usually excellent. However, little is known about the prognostic impact of HER2−amplification in this group. This study therefore, aimed to evaluate the relative and absolute prognostic impact of HER2−amplification in T1a/bN0 tumors.

Materials and Methods: Published data from studies assessing the outcomes of patients with HER2−amplified, node negative, T1a/bN0 tumors were included in a pooled analysis. Odds ratios (OR), 95% confidence intervals (CI) and absolute risks were computed for recurrence and distant recurrence at 5 years. Pooled hazard ratios (HR) for disease-free survival (DFS), were also assessed.

Results: A total of 3 case-control studies were included in the analysis and comprised 485 patients with HER2−amplified breast cancer (57.3% were also hormone receptor positive) and 1096 patients with HER2−normal disease (82.2% were hormone receptor positive). Among the HER2−amplified group, 4.1% received trastuzumab and 18.6% received chemotherapy. In the HER2−normal group, 4.3% received chemotherapy Estimated median follow-up was 5.7 years. HER2−amplification was associated worse DFS (HR = 2.60, 95% CI 1.53−4.41, p&lt;.001) and increased odds for recurrence at 5 years (OR = 3.79, 95% CI 2.35−6.10, p&lt;.001). There was a non-significant trend towards increased odds of distant recurrence at 5 years (OR = 2.51, 95% CI 0.82−7.67, p=.11). Compared with HER2−normal cancers, those with HER2−amplification showed lower absolute probability of recurrence-free survival at 5 years (90.1% vs. 94.6%, p&lt;.001) and distant recurrence-free survival at 5 years (95.1% vs. 97.6%, p&lt;.001). Among HER2−amplified cancers, tumor size 0.6−1.0cm (T1b) was associated with a trend for higher odds of recurrence at 5 years compared with those 0.5cm or smaller (T1a, pooled OR = 1.58, 95% CI 0.96−2.60, p=.07).

Conclusions: HER2−amplification is associated with worse outcome in T1a/bN0 tumors. However, recurrence-free and distant recurrence-free survival at 5 years is excellent in this group, particularly in those with T1a tumors. These data question the role of adjuvant chemotherapy and trastuzumab in these patients unless associated with other high risk features. A differentially lower risk for distant recurrence suggests the possible role for more aggressive local therapy such as surgery and/or radiation therapy.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P2-12-07.

P4-16-08: Pilot Randomized Trial of De-Escalated (q12 Weekly) Versus Standard (q3-4 Weekly) Intravenous Bisphosphonates in Women with Low-Risk Bone Metastases from Breast Cancer

Background: Bone-targeted agent such as bisphosphonates (BPs) can reduce skeletal complications from bone metastases but have no effect on either disease progression or survival. Despite substantial variability in the frequency and severity of skeletal complications, patients are empirically treated with BPs at the same dose and schedule irrespective of their individual risk.

Materials and Methods: A pilot, randomized, non-inferiority trial was conducted. Patients with low-risk bone metastases (serum C-telopeptide [CTx] &lt;600ng/L after at least 3 cycles of monthly IV BP) were assigned to pamidronate 90mg IV either every 3–4 weeks (control) or every 12 weeks (de-escalated). Data on serum CTx and bone alkaline phosphatase (BAP), pain scores (brief pain inventory [BPI] and functional assessment of cancer therapy-bone pain [FACT-BP]) were collected at 12 weekly intervals for 48 weeks.

Results: Fifty-four patients were approached, 44 provided consent and 38 were eligible for randomization. Median age was 55 (range 29–77) and mean baseline CTx was 319ng/L (range 10–526). Thirty-five participants (92%) completed the trial, 2 withdrew consent and one participant died. Fourteen control group participants (73.7%) and 13 experimental group participants (68.4%) maintained CTx in the low risk range (test for two proportions p=0.64). All patients not maintaining CTx in the low risk range showed evidence of both visceral and bone progression. Compared to the control group, there was a trend towards increasing CTx with time in the experimental group (p=0.10). There was no significant difference in BAP (p=0.37), BPI (p=0.21) or FACT-BP scores (p=0.59) between the two groups. Over the 48 week follow-up, two skeletal events were observed in each group.

Conclusions: Randomized trials of de-escalated BP therapy in women with low-risk bone metastases are feasible. Twelve-weekly pamidronate appears non-inferior to 3–4 weekly treatment. Larger trials are required to assess whether; 1) increasing CTx levels with de-escalated therapy will lead to higher rates of skeletal complications and 2) whether BP should be given every 3–4 weeks in patients with progressive visceral and bone disease.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-16-08.

DeltaT50--a new method to assess temporal ventricular repolarization variability

BACKGROUND

Increased beat-to-beat variability in cardiac repolarization time is a tentative risk marker of drug-induced torsades de pointes. We developed a new, automatic method based on the temporal variability of the T-wave down slope to assess this variability.

METHOD AND RESULTS

Leads V(1) to V(6) of resting electrocardiograms were recorded in 42 healthy subjects (18-68 years, 22 men). The temporal variability at 50% of the T-wave down slope, deltaT50 (1.5 ± 0.41 milliseconds; range, 0.86-2.66 milliseconds), was measured with an accuracy of 1 millisecond on at least 9 pairs of electrocardiogram complexes with a signal-to-noise ratio more than 10 and changes in the R-R interval less than 150 milliseconds. The correlation between repeated measurements of deltaT50 was high. DeltaT50 was measured without corrections for age, sex, heart rate, T-wave amplitude, signal-to-noise ratio, R-R variability, and QTcF because none of these factors explained more than 4% of the within-subject deltaT50 variability.

CONCLUSION

The beat-to-beat repolarization variability was measured with high fidelity with the deltaT50 method and was a robust measure in healthy volunteers.

Lhx2 is required for patterning and expansion of a distinct progenitor cell population committed to eye development

Progenitor cells committed to eye development become specified in the prospective forebrain and develop subsequently into the optic vesicle and the optic cup. The optic vesicle induces formation of the lens placode in surface ectoderm from which the lens develops. Numerous transcription factors are involved in this process, including the eye-field transcription factors. However, many of these transcription factors also regulate the patterning of the anterior neural plate and their specific role in eye development is difficult to discern since eye-committed progenitor cells are poorly defined. By using a specific part of the Lhx2 promoter to regulate Cre recombinase expression in transgenic mice we have been able to define a distinct progenitor cell population in the forebrain solely committed to eye development. Conditional inactivation of Lhx2 in these progenitor cells causes an arrest in eye development at the stage when the optic vesicle induces lens placode formation in the surface ectoderm. The eye-committed progenitor cell population is present in the Lhx2^−/− embryonic forebrain suggesting that commitment to eye development is Lhx2-independent. However, re-expression of Lhx2 in Lhx2^−/− progenitor cells only promotes development of retinal pigment epithelium cells, indicating that Lhx2 promotes the acquisition of the oligopotent fate of these progenitor cells. This approach also allowed us to identify genes that distinguish Lhx2 function in eye development from that in the forebrain. Thus, we have defined a distinct progenitor cell population in the forebrain committed to eye development and identified genes linked to Lhx2's function in the expansion and patterning of these progenitor cells.

Continuing high early death rate in acute promyelocytic leukemia: a population-based report from the Swedish Adult Acute Leukemia Registry

Our knowledge about acute promyelocytic leukemia (APL) patients is mainly based on data from clinical trials, whereas population-based information is scarce. We studied APL patients diagnosed between 1997 and 2006 in the population-based Swedish Adult Acute Leukemia Registry. Of a total of 3897 acute leukemia cases, 3205 (82%) had non-APL acute myeloid leukemia (AML) and 105 (2.7%) had APL. The incidence of APL was 0.145 per 100,000 inhabitants per year. The median age at the time of diagnosis was 54 years; 62% were female and 38% male. Among younger APL patients, female sex predominated (89% of patients <40 years). Of the 105 APL patients, 30 (29%) died within 30 days (that is, early death (ED)) (median 4 days) and 28 (26%) within 14 days from diagnosis. In all, 41% of the EDs were due to hemorrhage; 35% of ED patients never received all-trans-retinoic acid treatment. ED rates increased with age but more clearly with poor performance status. ED was also associated with high white blood cells, lactate dehydrogenase, creatinine, C-reactive protein and low platelet count. Of non-ED patients, 97% achieved complete remission of which 16% subsequently relapsed. In total, 62% are still alive at 6.4 years median follow-up. We conclude that ED rates remain very high in an unselected APL population.

Electrophysiologic and antiarrhythmic effects of AZD1305 in canine pulmonary vein sleeves

The objective of this study was to examine the electrophysiologic and antiarrhythmic effects of the new antiarrhythmic agent tert-butyl (2-[7-[2-(4-cyano-2-fluorophenoxy)ethyl]-9-oxa-3,7-diazabicyclo[3.3.1]non3-yl]ethyl)carbamate (AZD1305) in canine pulmonary vein (PV) sleeve preparations isolated from untreated and long-term amiodarone-treated animals. Ectopic activity arising from PV sleeves plays a prominent role in the development of atrial fibrillation (AF). Delayed afterdepolarizations (DADs) and late phase 3 early afterdepolarizations (EADs), originating from the PV have been proposed as potential triggers in initiation of AF. Action potentials were recorded from canine superfused PV sleeves using standard microelectrode techniques. Acetylcholine (1 microM), isoproterenol (1 microM), or their combination was used to induce EADs, DADs, and triggered activity (TA). The effects of AZD1305 (0.1-10 microM) were evaluated in PV sleeve preparations isolated from untreated and amiodarone-treated (40 mg/kg daily for 6 weeks) dogs. AZD1305 (0.1-10 microM, 30 min) significantly prolonged action potential duration and reduced excitability. Abbreviating basic cycle length from 1000 to 300 ms resulted in a decrease of V(max) from 314 +/- 79 to 251 +/- 55 V/s (Delta = -20%) in control and from 177 +/- 53 to 76.5 +/- 33 V/s (Delta = -57%) after AZD1305 (n = 6, p < 0.05). AZD1305 markedly attenuated or suppressed DADs and DAD-induced TA, but not late phase 3 EADs. AZD1305-induced attenuation of excitability, leading to activation failure at much longer cycle lengths, was much more pronounced in PV from amiodarone-treated dogs. Potent effects of AZD1305 to depress excitability, prolong action potential duration, and suppress DAD-induced triggered activity in canine PV sleeve preparations may be effective in suppressing triggers responsible for the genesis of AF and other atrial arrhythmias.