A228: Idenfitication of cancer cell responses to hypoxia mediated by protein cysteine modifications
1The Francis Crick Institute, Mill Hill Laboratory, London NW7 1AA, UK,2Department of Chemistry, Boston College, 2609 Beacon Street, Chestnut Hill, MA 02467, USA,3University of Leicester, University Road, Leicester LE1 7RH, UK
In many solid tumours, hypoxic regions can develop where local oxygen supply is unable to cover cellular metabolic demands due to rapid proliferation of cancer cells and a highly disorganized vasculature. Intratumoral hypoxia has been linked to tumour invasiveness, metastasis and resistance to anticancer therapy and has been proposed as a prognostic marker.
Microenvironmental factors, such as limited drug penetration and ineffectiveness of ionising radiation due to low oxygen pressure, are thought to partly cause hypoxia-associated resistance to anticancer therapies. However, cellular hypoxia signalling and adaptation to low oxygen concentrations itself are emerging as important promoters of cancer cell growth and survival.
An early cellular response to hypoxia is increased production of reactive oxygen species (ROS). ROS have been implicated in cellular signalling primarily through their ability to oxidise reactive cysteines in proteins. Previous findings1 suggest that ROS are required for hypoxia signalling and mediate some aspects of metabolic adaptation to hypoxia.
In this project we aim to systematically investigate ROS-dependent regulatory mechanisms in hypoxia. We identified targets of ROS-mediated cysteine oxidation in cancer cells using an unbiased, proteome-wide method for detection and quantification of differential cysteine modifications2.
We present a workflow for identification and quantification of cysteine modifications from human cancer cells lines in hypoxia, including statistical evaluation using empirical Bayesian analysis3 to separate reliably detected modifications from technical noise.
Using this workflow, we have identified a number of promising candidates that we are currently validating and we will investigate their roles in cancer cell physiology under hypoxia.