Carolan

Malignant pleural mesothelioma (MPM) is an aggressive cancer associated with asbestos exposure. MPM is often diagnosed late, at a point where limited treatment options are available, but early intervention could improve the chances of successful treatment for MPM patients. Biomarkers to detect MPM in at-risk individuals are needed to implement early diagnosis technologies. Volatile organic compounds (VOCs) have previously shown diagnostic potential as biomarkers when analysed in MPM patient breath. In this study, chorioallantoic membrane (CAM) xenografts of MPM cell lines were used as models of MPM tumour development for VOC biomarker discovery with the aim of generating targets for investigation in breath, biopsies or other complex matrices. VOC headspace analysis of biphasic or epithelioid MPM CAM xenografts was performed using solid-phase microextraction and gas chromatography-mass spectrometry. We successfully demonstrated the capture, analysis and separation of VOC signatures from CAM xenografts and controls. A panel of VOCs was identified that showed discrimination between MPM xenografts generated from biphasic and epithelioid cells and CAM controls. This is the first application of the CAM xenograft model for the discovery of VOC biomarkers associated with MPM histological subtypes. These findings support the potential utility of non-invasive VOC profiling from breath or headspace analysis of tissues for detection and monitoring of MPM.

Malignant mesothelioma (MM) is an incurable cancer. MM is often misdiagnosed, with a poor 5-year survival and limited treatment options. The discovery of endogenous volatile organic compounds (VOCs) is required in order to accelerate the development of a breath test as an alternative to conventional MM diagnosis. For the first time, this study used solid-phase microextraction and gas chromatography-mass spectrometry to identify VOCs released directly from the biphasic MM cell line MSTO-211H and the epithelioid MM cell line NCI-H28 as well as the non-malignant mesothelial cell line MET-5A. Multivariate statistical analysis showed separation between MSTO-211H, NCI-H28 and MET-5A results. 2-ethyl-1-hexanol was significantly increased in both MSTO-211H and NCI-H28 cells compared to MET-5A controls. In addition, ethyl propionate and cyclohexanol were significantly increased in MSTO-211H cells and dodecane was significantly increased in NCI-H28 cells. This is the first study reporting headspace analysis of these MM cell lines and the first to consider the effects of mesothelioma sub-type on VOC profile. Current results further highlight the potential for a diagnostic mesothelioma breath test as well as providing proof of concept for the differentiation between biphasic and epithelioid mesothelioma based on VOC profiles.

This study investigates the identity of two unexpected arsenic species found separately in a number of urine samples sent to the Health and Safety Executive’s Health and Safety Laboratory for arsenic speciation (arsenobetaine, AB; arsenite, As³⁺; arsenate, As⁵⁺; monomethylarsonic acid, MMA⁵⁺; and dimethylarsinic acid, DMA⁵⁺). Micro liquid chromatography coupled to inductively coupled plasma mass spectrometry (µLC-ICP-MS) and electrospray time of flight tandem mass spectrometry (ESI-QqTOF-MS/MS) were used to identify the two arsenic peaks by comparison to several characterized arsenicals: arsenocholine, AC; trimethyl arsine oxide, TMAO; dimethylarsenoacetate, DMAA; dimethylarsenoethanol, DMAE; thio-dimethylarsinate, thio-DMA; thio-dimethylarsenoacetate, thio-DMAA and thio-dimethylarsenoethanol, thio-DMAE. The results from both the ICP-MS and ESI-QqTOF-MS/MS investigations indicate that the unexpected arsenic species termed peak 1 was thio-DMA. While the unexpected arsenic species termed peak 2 has yet to be identified, this investigation shows that it was not AC, TMAO, DMAA, DMAE, thio-DMA, thio-DMAA or thio-DMAE. This study demonstrates the incidence of unexpected arsenic species in both routine and non-routine urine samples from both workers and hospital patients.

Rationale: 5,6‐Dimethylxanthenone‐4‐acetic acid (DMXAA) is a low molecular weight drug of the flavonoid group, which has an anti‐vascular effect in tumours causing endothelial cell apoptosis and activation of cytokines. Flavonoid‐based compounds have been reported to lead to an upregulation in the expression of lysophosphatidylcholines (LPC)‐type lipids in solid tumours. A study employing TLC/MALDI‐MS and MALDI‐MS imaging to examine LS174T colorectal adenocarcinoma xenografts following administration of DMXAA has been conducted into this effect. Methods: LS174T colorectal adenocarcinoma xenografts grown in male immune‐deficient mice were treated with 27.5 mg/kg DMXAA. The control (before treatment) and 4 h and 24 h post‐treatment tumours were excised and divided into two. MALDI‐MS imaging experiments were carried out on 12 µm cryosections sections taken from one half of the tumours and from the other half the lipids were extracted and analysed by TLC/MALDI‐MS. These experiments were carried out in triplicate. Results: Statistical analysis of the MALDI‐MS imaging data set indicated an increased amount of LPC in the 24 h post‐treated sample and a decreased amount of PC in the 24 h post‐treated sample, compared with the 4 h post‐treated sample and the control. These effects were confirmed by the TLC/MALDI‐MS data. The lipid extracts were separated into six spots on the TLC plate. These were identified as arising from different lipids classes, i.e. LPC, sphingomyelins (SM), phosphatidylcholines (PC) and phosphatidylethanolamines (PE). The TLC/MALDI‐MS data indicated that LPC were highly expressed in the 4 h and 24 h post‐treated tumour samples compared with the control. Examination of the mass spectrometric images confirms this increase and demonstrates additionally that the increase in the signals arising from LPC appears to be localised primarily within the central areas of the xenograft. Conclusions: An increase in expression of LPC lipids in solid tumours treated with DMXAA has been demonstrated and shown to be localised in the central area of the tumour. Copyright © 2015 John Wiley & Sons, Ltd.

Abstract: Hypoxia is a common feature observed in solid tumours. It is a target of interest in oncology as it has been found to be closely associated with tumour progression, metastasis and aggressiveness and confers resistance to a variety of chemotherapeutic agents as well as radiotherapy. AQ4N, also known as banoxatrone or 1,4-bis-[2-(dimethylamino-Noxide) ethyl]amino-5,8-dihydroxyanthracene-9,10-dione is a very promising bioreductive prodrug. This paper, describes an application of MALDI-MSI combined with ion mobility separation and an "on-tissue" bottom up proteomic strategy to obtain proteomic data from AQ4N dosed tumour xenograft tissue sections. These data are then correlated with the drug distribution determined also using MALDI-ion mobility separation-mass spectrometry imaging (MALDI-IMS-MSI). PCA-DA and OPLS-DA have been used to compare treated and untreated xenografts and of note is the marked increase in expression of Histone H3.

Inorganic and methylmercury content in human hair has previously been determined using different analytical techniques for each species. In this study a single method, allowing the separation and determination of mercury species in human hair, is developed. Using a HPLC-ICP-MS system it is possible to separate inorganic and methylmercury in hair, without any modifications to the existing instrumentation. The results showed that in order to determine methylmercury as well as inorganic mercury the hair sample must be cold digested with 2 ml of concentrated nitric acid plus 1 ml of hydrogen peroxide and that a minimum of 0.1 g hair is required. Hair washing procedures are also investigated to remove exogenously bound species. It is seen that when hair is soaked with simulated sweat solution containing both inorganic and methylmercury and then washed with 0.1 M HCl all the methylmercury, both existing and spiked, can be removed from the hair sample. However, only 65% of the spiked inorganic mercury can be removed by washing with 0.1 M HCl, the rest being irreversibly bound to the hair.