The gold standard for understanding the connection between tumor metabolism, tumor progression and ultimately therapeutic efficacy is the human subject, but more detailed information is needed from appropriate better controlled models. We have begun a Stable Isotope Resolved Metabolomics (SIRM) study of non-small cell lung cancer (NSCLC) from patients who underwent surgical resection. In our pilot study we capitalized on the inherent power of the matched pairs of malignant and benign lung tissue and the use of """"""""C-labeled glucose administered iv prior to surgery to map in situ intracellular metabolic pathways for the first time. This led to the discovery that mitochondrial pyruvate carboxylase (PCB) is activated to replenish Krebs cycle intermediates required for biosynthesis (i.e. anaplerosis) in tumors. This was further corroborated by increased mRNA and protein expression of PCB in the tumors compared with the paired benign lung tissue, as well as growth inhibition of NSCLC cells by PCB knockdown. Critical to the interpretation of these studies was the additional detailed information that we obtained on cell culture, and mouse models, which provided metabolic signatures to look for in the tumor tissue.). Our preliminary findings also indicate that there are many more metabolic distinctions in lung tumors;the underlying pathways and regulation have yet to be defined. We now seek to extend the approach to a larger cohort of NSCLC and added a new ex vivo """"""""Warburg"""""""" tissue slice approach to better define in large-scale the metabolic reprogrammings in NSCLC with prevailing driver gene defects. These direct human studies will be conducted in parallel with model cell (Project 1) and animal studies (Project 2) to facilitate interpretation. We will also apply this integrated approach to explore the metabolic mechanism underlying the tumor-regressive effect of a pre-operative treatment with beta-glucans. We hypothesize that this effect may be in part mediated by beta-glucan's activation of glucose and Gin metabolism in resident macrophages, a key immune modulator in the tumor microenvironment, based on our most recent data and the literature (cf. Project 2). We will further explore the linkage of lung tumor tissue to blood plasma metabolism via the lipidic microvesicles (MV), known to be released by lung cancer cells with metastasis-promoting capacity. We have new evidence that the lipid profile of plasma MV is distinct among early stages of lung and breast cancer patients and healthy subjects. We will test if beta-glucan treatment can alter MV metabolic signatures for future application as clinical indicators. These goals will be achieved via the three specific aims.
Deaths from lung cancer are the highest among all cancers in North America and cure rates remain low. We seek to gain a deeper understanding of lung cancer biochemistry using a novel approach we developed. Improved knowledge will have direct impact on early diagnosis and prognosis. The biochemical differences between lung cancer subtypes can be related to appropriate treatments.
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