An autocrine ATP release mechanism regulates basal ciliary activity in airway epithelium

KEY POINTS

Extracellular ATP, in association with [Ca²⁺ ]_i regulation, is required to maintain basal ciliary beat frequency. Increasing extracellular ATP levels increases ciliary beating in airway epithelial cells, maintaining a sustained response by inducing the release of additional ATP. Extracellular ATP levels in the millimolar range, previously associated with pathophysiological conditions of the airway epithelium, produce a transient arrest of ciliary activity. The regulation of ciliary beat frequency is dependent on ATP release by hemichannels (connexin/pannexin) and P2X receptor activation, the blockage of which may even stop ciliary movement. The force exerted by cilia, measured by atomic force microscopy, is reduced following extracellular ATP hydrolysis. This result complements the current understanding of the ciliary beating regulatory mechanism, with special relevance to inflammatory diseases of the airway epithelium that affect mucociliary clearance.

ABSTRACT

Extracellular nucleotides, including ATP, are locally released by the airway epithelium and stimulate ciliary activity in a [Ca²⁺ ]_i -dependent manner after mechanical stimulation of ciliated cells. However, it is unclear whether the ATP released is involved in regulating basal ciliary activity and mediating changes in ciliary activity in response to chemical stimulation. In the present study, we evaluated ciliary beat frequency (CBF) and ciliary beating forces in primary cultures from mouse tracheal epithelium, using videomicroscopy and atomic force microscopy (AFM), respectively. Extracellular ATP levels and [Ca²⁺ ]_i were measured by luminometric and fluorimetric assays, respectively. Uptake of ethidium bromide was measured to evaluate hemichannel functionality. We show that hydrolysis of constitutive extracellular ATP levels with apyrase (50 U ml^-1 ) reduced basal CBF by 45% and ciliary force by 67%. The apyrase effect on CBF was potentiated by carbenoxolone, a hemichannel inhibitor, and oxidized ATP, an antagonist used to block P2X7 receptors, which reduced basal CBF by 85%. Additionally, increasing extracellular ATP levels (0.1-100 μm) increased CBF, maintaining a sustained response that was suppressed in the presence of carbenoxolone. We also show that high levels of ATP (1 mm), associated with inflammatory conditions, lowered basal CBF by reducing [Ca²⁺ ]_i and hemichannel functionality. In summary, we provide evidence indicating that airway epithelium ATP release is the molecular autocrine mechanism regulating basal ciliary activity and is also the mediator of the ciliary response to chemical stimulation.

[Treatment of bilateral spontaneous pneumothorax during pazopanib therapy for pulmonary soft tissue sarcoma metastases. What to do when there is so few evidence?]

Soft tissue sarcomas are rare malignant tumors with a great variety of histological types and different response to multimodality treatment. Pazopanib has been recently introduced for the treatment of non-adipocytic metastatic soft tissue sarcomas which are resistant to conventional chemotherapy. Spontaneous pneumothorax is a rare but well recognized complication of this molecule and its treatment is quite challenging. The case reported herein describes the surgical management of a simultaneous bilateral spontaneous pneumothorax in a patient with pulmonary metastases treated with pazopanib. It underlines the fact that the main objective should be the maintenance of the treatment in patients who benefit from it. Close oncologic and surgical collaboration is crucial in order to deal with adverse effects due to the anti-angiogenic action of pazopanib.

Abstract P1-08-06: SToRM: A prospective clinical trial of 1502 metastatic breast cancer (mBC) patients with detail of clinical presentation, molecular subtype, treatment modalities, prognosis and GWAS genotyping

Background: Due to better molecular classification and new treatment options, epidemiology and prognosis of mBC is rapidly changing. Clinical data extracted from randomized studies are only relevant to specific subpopulations and retrospective studies are prone to selection bias. SToRM is a prospective clinical trial that aims to create a cohort of 1500 mBC patients, with the ultimate goal of identifying germ line polymorphisms associated with prognosis of breast cancer (BC) and response to treatment in the metastatic phase.

Material and methods: Any newly (within 1 year) diagnosed mBC patients were eligible. Whole blood samples were drawn and germline DNA extracted for genetic analysis. Extensive epidemiologic data, disease history from primary diagnosis to metastatic spread, pathological characteristics and ER, PR and HER2 status were collected. Patients are prospectively followed until death. Genotyping using the HumanCoreExome chipset from Illumina is currently underway and will be completed in early summer 2015.

Results: 1502 patients were included from March 2012 to May 2014 from 71 French institutions. Median age at metastatic relapse was 60 years (range 26-93). Median time from primary diagnosis to metastatic relapse was 30 months (range 0-473) with 24% of patients already metastatic at initial diagnosis. 78% of patients were ER+, 18% were HER2+ and only 16% were triple negative. Molecular subtype classification derived from pathological data following St Gallen consensus recommendations is presented below:

 n (%)Luminal A like261 (22.2%)Luminal B like HER2 negative476 (40.5%)Luminal B like HER2 positive134 (11.4%)HER2 positive non Luminal (ER-)111 (9.5%)Triple negative193 (16.4%)Missing data327

64% of the patients had received previous adjuvant treatment, among which 81% received adjuvant chemotherapy and 9% trastuzumab.

At metastatic relapse, loco-regional progression, liver, lung and bone metastasis were documented in 301 (20%), 494 (33%), 410 (27%) and 1017 (68%) patients respectively. 313 patients (21%) had bone only metastatic disease. First line treatment included: chemotherapy (71%), endocrine therapy (50%) and anti-HER2 treatments (17%). Survival data will be presented at the meeting.

Conclusion: Despite a theoretically better prognosis and widespread use of adjuvant hormonal treatment, ER+/HER2- breast cancer still account for more than 60% of mBC. The proportion of patients with HER2+ disease (18%) and triple negative disease (16%) is consistent with percentages observed in early BC populations. In comparison with a cohort of "cured", localized cancer, such as the SIGNAL/PHARE study, GWAS analysis will allow for the identification of genetic polymorphisms correlated with treatment resistance. Fundamentally, such variants will provide insight into the molecular mechanisms responsible for host-genetic influence on BC progression. From a clinical perspective, genetic variants that predispose to metastatic disease can serve as stratification variables in future clinical trials, particularly as the development of new treatment options for resistant BC is needed.

Citation Format: Bachelot T, Lavergne E, Romieu G, Rios M, Heudel P-E, Roemer-Becuwe C, Jouannaud C, Tredan O, Chaigneau L, Arnedos M, Orfeuvre H, Petit T, Quenel-Tueux N, Jacquin J-P, Ferrero J-M, Moullet I, Abadie-Lacourtoisie S, Penault-Llorca F, Blanc E, Cox D. SToRM: A prospective clinical trial of 1502 metastatic breast cancer (mBC) patients with detail of clinical presentation, molecular subtype, treatment modalities, prognosis and GWAS genotyping. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P1-08-06.

Low physiological levels of prostaglandins E2 and F2α improve human sperm functions

Prostaglandins (PGs) have been reported to be present in the seminal fluid and cervical mucus, affecting different stages of sperm maturation from spermatogenesis to the acrosome reaction. This study assessed the effects of low physiological PGE2 and PGF2α concentrations on human sperm motility and on the ability of the spermatozoa to bind to the zona pellucida (ZP). Human spermatozoa were isolated from seminal samples with normal concentration and motility parameters and incubated with 1 μM PGE2, 1 μM PGF2α or control solution to determine sperm motility and the ability to bind to human ZP. The effects of both PGs on intracellular calcium levels were determined. Incubation for 2 or 18 h with PGE2 or PGF2α resulted in a significant (P < 0.05) increase in the percentage of spermatozoa with progressive motility. In contrast with PGF2α, PGE2 alone induced an increase in sperm intracellular calcium levels; however, the percentage of sperm bound to the human ZP was doubled for both PGs. These results indicate that incubation of human spermatozoa with low physiological levels of PGE2 or PGF2α increases sperm functions and could improve conditions for assisted reproduction protocols.

Involvement of a P2X7 Receptor in the Acrosome Reaction Induced by ATP in Rat Spermatozoa

The acrosome reaction (AR) is the exocytosis of the acrosomal vesicle in response to different physiological and non-physiological stimuli. Particularly in mammals, the AR is needed for sperm to fuse with the oocyte plasma membrane, and it occurs only in capacitated sperm. Previous evidence in the literature indicates that extracellular ATP induces the AR in capacitated human and bovine spermatozoa, but its receptor has not yet been identified. The aim of this work was to define a putative ATP receptor in rat spermatozoa using pharmacological and biochemical approaches. We found that ATP induced the AR only in capacitated rat spermatozoa, which was inhibited in the presence of two general inhibitors of ATP receptors (P2 receptors), Suramin, and oxidized ATP (oATP), and one inhibitor of P2X receptor (pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid [PPADS]). In addition, the AR induced by ATP in capacitated rat spermatozoa was inhibited by brilliant blue-G (BB-G) and 17-β-oestradiol, two blockers of P2X7 receptors. Moreover, the ATP analog 2'(3')-O-(4-benzoylbenzoyl) ATP (BzATP) was almost 500 times more potent than ATP to induce the AR, which agrees with the pharmacology of a P2X7 receptor. Here, we show the presence of P2X7 receptor by Western blot and its localization in the tail and acrosome by indirect immunofluorescence. Finally, we quantify the presence of ATP in the rat oviduct during the estrous cycle. We found that the ATP concentration within the lumen of the oviduct is similar to those required to induce acrosome reaction, which agree with its role during in vivo fertilization. Therefore, our results strongly suggest that ATP induces the AR in capacitated rat spermatozoa through a P2X7 receptor, which may be functional during in vivo fertilization.

Efficacy of trabectedin in malignant solitary fibrous tumors: a retrospective analysis from the French Sarcoma Group

Background

Advanced malignant solitary fibrous tumors (SFTs) are rare soft-tissue sarcomas with a poor prognosis. Several treatment options have been reported, but with uncertain rates of efficacy. Our aim is to describe the activity of trabectedin in a retrospective, multi-center French series of patients with SFTs.

Methods

Patients were mainly identified through the French RetrospectYon database and were treated between January 2008 and May 2013. Trabectedin was administered at an initial dose of 1.5 mg/m², q3 weeks. The best tumor response was assessed according to the Response Evaluation Criteria In Solid Tumors 1.1. The Kaplan–Meier method was used to estimate median progression-free survival (PFS) and overall survival (OS). The growth-modulation index (GMI) was defined as the ratio between the time to progression with trabectedin (TTP_n) and the TTP with the immediately prior line of treatment (TTP_n-1).

Results

Eleven patients treated with trabectedin for advanced SFT were identified. Trabectedin had been used as second-line treatment in 8 patients (72.7 %) and as at least third-line therapy in a further 3 (27.3 %). The best RECIST response was a partial response (PR) in one patient (9.1 %) and stable disease (SD) in eight patients (72.7 %). Disease-control rate (DCR = PR + SD) was 81.8 %. After a median follow-up of 29.2 months, the median PFS was 11.6 months (95 % CI = 2.0; 15.2 months) and the median OS was 22.3 months (95 % CI = 9.1 months; not reached). The median GMI was 1.49 (range: 0.11–4.12).

Conclusion

Trabectedin is a very promising treatment for advanced SFTs. Further investigations are needed.

Collaborative study for the characterization of a chikungunya virus RNA reference reagent for use in nucleic acid testing

BACKGROUND AND OBJECTIVES

Infections with the mosquito-borne chikungunya virus (CHIKV) can cause febrile illness or be asymptomatic. Laboratory diagnosis of CHIKV is often made with laboratory-developed nucleic acid amplification technology (NAT) assays because there are no U.S. Food and Drug Administration (FDA)-approved diagnostic or blood screening assays. We aimed to produce a well-characterized CHIKV RNA reference reagent (CHIKV-RR) for use in NAT assays.

MATERIALS AND METHODS

A CHIKV RNA-RR consisting of cell culture-grown, heat-inactivated CHIKV diluted in human plasma was assessed by 8 laboratories in a collaborative study. The participants were asked to test the CHIKV-RR using their NAT assay(s) by qualitative testing (determination of RNA end-point by testing log and half-log dilutions followed by calculation of estimated NAT-detectable units/ml, after adjustment for the sample volume used for testing), and by quantitative testing, when available.

RESULTS

Results from the testing showed that the CHIKV-RR had an estimated overall mean of 7.56 log10 detectable units/ml, ranging from 6.2 log10 to 8.6 log10.

CONCLUSIONS

The Center for Biologics for Evaluation and Research/FDA CHIKV RNA-RR for NAT was established with a concentration of 7.56 log10 detectable units/ml.

Force-time course parameters and force fatigue model during an intermittent fatigue protocol in motorcycle race riders

Fatigue in forearm muscles may be critical for motorcycle riders in relation to performance and forearm disorders. Force-time course parameters were examined to better characterize the reduction in the maximal force generating capacity (MVC) during an intermittent fatigue protocol (IFP) specifically designed for motorcycle riders. Also, a mathematical force fatigue model is proposed. Forty motorcyclists (aged 27.6 ± 6.8 years) performed an IFP that simulated the braking gesture and posture of a rider. Fatigue was confirmed by a 40% decrement of the normalized MVC in comparison with basal value. Contraction time increased in comparison with basal condition (P ≤ 0.034). Relaxation kinetics presented two phases: (a) a pre-fatigue phase where half relaxation time (HRTraw ) and normalized (HRTnor ) decreased (P ≤ 0.013) while relaxation rate (RRraw ) remained unchanged; and (b) a fatiguing phase where HRTraw , HRTnor increased and RRraw decreased (P ≤ 0.047). Normalized RRraw (RRnor ) declined progressively (P ≤ 0.016). The proposed nonlinear force fatigue model confirmed a satisfactory adjustment (R(2)  = 0.977 ± 0.018). This mathematical expression derived three patterns of force fatigue: three-phase, exponential and linear, representing 70%, 13%, and 17% of the participants, respectively. Overall, these results provided further support to force fatigue theoretical and applied proposals.

Neurotrophins and the regulation of energy balance and body weight

Complex interactions between the brain and peripheral tissues mediate the effective control of energy balance and body weight. Hypothalamic and hindbrain neural circuits integrate peripheral signals informing the nutritional status of the animal and in response regulate nutrient intake and energy utilization. Obesity and its many medical complications emerge from the dysregulation of energy homeostasis. Excessive weight gain might also arise from alterations in reward systems of the brain that drive consumption of calorie dense, palatable foods in the absence of an energy requirement. Several neurotrophins, most notably brain-derived neurotrophic factor, have been implicated in the molecular and cellular processes underlying body weight regulation. Here, we review investigations interrogating their roles in energy balance and reward centers of the brain impacting feeding behavior and energy expenditure.

Abstract P1-08-27: Quantitative analysis of tumor expression of phosphoproteins from PI3-kinase and MAP-kinase signaling pathways as biomarkers of the biological and clinical activity of trastuzumab and everolimus in breast cancer: Unicancer RADHER phase II trial results

Background: PI3-kinase (PI3K) and MAP kinase (MAPK) are the main signaling pathways implicated in molecular oncogenesis. In breast cancer, inhibition of these signaling pathways has been largely envisaged by means of targeted therapy. Unicancer RADHER study aimed at evaluating the efficacy of adding everolimus (E) to trastuzumab (T) as preoperative therapy for primary HER2+ operable breast cancer patients and to evaluate molecular response biomarkers. We report here the investigation of the expression of phosphoproteins from PI3K and MAPK signaling pathways as predictive biomarkers of clinical and pathological response as well as pharmacodynamic markers of treatment activity.

Methods: 82 eligible patients were randomized to receive T alone (loading dose 4 mg/kg, then 2 mg/kg/week), or T+E (10 mg/day) for a 6-week pre-operative treatment. Clinical response rate (cRR) was determined from OMS criteria with complete and partial responses being considered as “ responders “ and stable and progressive diseases as “ non responders “. Pathological response rate was evaluated according to Sataloff classification, with Ta and Tb being considered as “ responders “ and, Tc and Td as “ non responders “. The expression levels of phosphorylated-AKT (p-AKT), p-GSK3b, p-S6 kinase, p-MEK1, p-ERK1/2, p-P90RSK, p-IGF1R as well as p-P38MAPK were quantitatively assessed using multiplex bead immuno-assay. All patients had baseline needle frozen biopsies taken before initiation of the treatment, at cycle 4 as an option and at surgery. Before being submitted to total protein extraction, all biopsies were validated by a senior pathologist after HE slide examination to ensure a tumor content &gt;50%. 36 pairs associating baseline + surgery tumor specimens and 4 pairs of baseline + cycle 4 biopsies were eligible for protein extraction. Results: No statistically significant relationship was observed between the expression level of any of the phosphoproteins in the initial biopsies and neither the clinical nor the pathological response, overall. After treatment, as compared to the level of expression measured in the initial biopsies, a significant increase of p-GSK3β, p-MEK1, p-ERK1/2, p-P38MAPK was observed in T+E arm and a significant decrease in p-S6 kinase expression in the global patient population. No significant variation was observed in T arm. Additional analysis with immunohistochemistry data is planned and will be presented.

Conclusion: In the present study, measuring phosphoproteins expression showed that combining E with T, altered the regulation of signaling proteins from PI3-Kinase and MAP-kinase pathways. No response predictive biomarker could be identified among the phosphoproteins analyzed tending to show that the clinical and pathological response to T and T+E should be driven by additional mechanisms. As a whole, these results validate the use of multiplex bead immuno-analysis for determination of phosphorylated signaling proteins in clinical needle biopsies from breast cancer specimens and its prospective evaluation as biomarker for the activity of targeted therapies.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-08-27.

Tumours and pseudotumours of the soft tissue in adults: perspectives and current role of sonography

Soft tissue tumours of the musculoskeletal system are reported relatively frequently. The quality of the information gained from different imaging modalities (Doppler sonography, multislice CT, MRI spectroscopy, and diffusion MRI) means that in a growing number of situations, we can envisage determining with great accuracy not only the usual information of tumour size and topography, but often the exact nature of the tissue, almost always identifying whether a lesion is aggressive or not. Of all these techniques, Doppler sonography has become the most widely used due to the striking improvements in its sensors, especially for superficial applications. Some other recent developments are: panoramic imaging, elastography (although its current contribution is still to be determined but it seems to offer promising potential), and, most importantly, specific contrast agents. These techniques have considerably refined the quality of the information obtained, and have particularly enhanced the degree of sensitivity with which lesion progression can be assessed. Ultrasonography is the very first investigation in our protocol. It is also very often used to close investigations, as it accurately guides core needle biopsy from these generally accessible lesions. The purpose of this article is to bring together updated information on the various collections of sonographic features seen in soft tissue tumours and pseudotumours and to emphasise the considerable contributions of these new technological developments, in particular contrast-enhanced sonography. The discussion will follow the World Health Organisation's anatomical pathology classifications of soft tissue tumours. We will close with a synthesis that summarises the main steps in our diagnostic process.