Early detection of malignant pleural mesothelioma (MPM) is likely to improve outcome in affected patients. From our previous studies (MesoBreath 1 & 2) we developed a screening tool in which volatile organic compounds (VOCs) in breath allowed discrimination of MPM patients from at risk controls. However it is not yet clear which VOCs arise from the neoplastic cells themselves or from the host response. Identifying the cancer cell-specific compounds should increase the specificity of our breathomic signature model. Therefore, we set up an in vitro experimental setup model for VOC analysis from the headspace of mesothelioma cell lines.
Standard polystyrene culture flasks (NunclonTM Delta Surface, Thermo Scientific) were mounted with an adapted cap accommodating teflon inlet and outlet tubes. The inlet tube provides environmental air while an external pump (Gilian GilAir Plus, Sensidyne) draws headspace air from the outlet tube over an adsorption column (Tenax GR, Markes International, UK). The adsorption columns were further processed on a GC-MS platform (GC: Focus GC, Thermo Finnigan, Milan, Italy; DSQII Single Quadrupole MS, Thermo Finnigan, Austin, TX, USA). VOC profiles were processed using supervised clustering algorithms and principal component analysis.
Using this setup, we have investigated the impact of flow and total sampled volume on the concentration and range of VOCs detected. For a constant flow, VOCs were detected in higher concentrations with increasing sample volume. For a constant volume, a lower sampling flow yielded a higher concentration of detected VOCs. Most of the VOCs obtained were alkanes and ketones. We will show data illustrating the differential VOC profiles of container plastic, cell culture medium and growing mesothelioma cancer cells, as well as the differential VOC output of epithelioid vs sarcomatoid mesothelioma cell lines.
We have succesfully developed an in vitro experimental setup allowing collection and analysis of VOCs emanating from mesothelioma cancer cell line cultures. This platform will allow us to investigate how VOC profiles are impacted in different experimental conditions (e.g. hypoxia, nutrient deprivation, cytostatics, co-culture with leukocytes). The data collected will help us to pinpoint the cancer cell-derived VOCs from patient exhaled breath, and increase the robustness of our mesothelioma breathomic signature.
Note: This abstract was not presented at the meeting.
Citation Format: Sabrina Lagniau, Kevin Lamote, Lore Vandermeersch, Herman Van Langenhove, Jan P. van Meerbeeck, Karim Y. Vermaelen. In vitro metabolomics of mesothelioma: Challenges and outcomes [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 204. doi:10.1158/1538-7445.AM2017-204