Live imaging study of metabolic change in pre-neoplastic cells and the host inflammation response in a zebrafish tumour model

The development and progression of cancer involves complex interplay between transformed cell and the host’s environment. Until recently, it was not possible to live image the earliest interactions between host and oncogene-transformed cells during tumour initiation. Earlier work in the lab using zebrafish as model organism has made it possible to visualize a transformed cell at its inception in vivo, and has revealed that the transformed cell elicits a Trophic Inflammatory response, in which recruited leukocytes promote transformed cell growth, at least in part, through COX-2 mediated PGE2 production. However, the mechanisms as to how and what inflammation modulating signals generated within the local milieu where the transformed-cell grows and interacts with its normal neighbours to elicit such a response remains unclear. One of the hallmarks for cancer is altered metabolism to meet the requirement of its fast growth rate. This has been described as the “Warburg effect”, which is characterised by an increased uptake of nutrients such as glucose. Moreover, in contrast to most normal tissues, where much of the glucose is oxidized through the tricarboxylic acid cycle in the mitochondria, transformed-cells preferentially convert glucose to lactate through glycolysis. The altered metabolism of cancer cells leads to generation of alternative metabolite. The current project aims to test whether these alternative metabolite might be involved in modulating immune cell interactions with pre-neoplastic cells in our zebrafish model. For this project we will be using a novel zebrafish inducible skin tumourigenesis model, in which pre-neoplastic cell clones expressing HRASG12V-eGFP can be induced in larval skin tissue with precise temporal control. We will characterize genetic encoded fluorescent reporters for several metabolites. We will then combine our inducible tumour model with metabolite reporters and use a live imaging approach to visualize the onset of metabolic change in the pre-neoplastic cells in real time and follow the movement of fluorescently labeled immune cells in response to the metabolic change of pre-neoplastic cells in vivo. We wish to learn when is the earliest detectable metabolic change in the pre-neoplastic cells after they emerge? Whether immune cell recruitment to pre-neoplastic cells is mediated by altered metabolites? And whether altered metabolites influence immune cell phenotype?