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ORAL 07 - Lung Cancer Pathogenesis (ID 91)
- Event: WCLC 2015
- Type: Oral Session
- Track: Biology, Pathology, and Molecular Testing
- Presentations: 1
ORAL07.02 - Metabolic Reprogramming in the Airway Epithelium of Individuals at High Risk for Lung Cancer (ID 2493)
10:45 - 12:15 | Author(s): S.M.J. Rahman
What defines the high risk airway epithelium for lung cancer remains a major challenge. Airway epithelium is prone to assault by the risk factors and considered to be the primary cell type involved in the field cancerization. Transcriptomic aberrations in the airway epithelium of individuals at risk for lung cancer have been reported earlier. However, very limited information exists about proteomic alterations in the airway epithelium. We investigated the molecular underpinnings of risk from proteomic alterations in the cytologically normal airway epithelium from individuals at risk for developing lung cancer.
Bronchial brushings specimens were collected from individuals categorized as low, medium and high risk groups based on Bach risk model. Shotgun proteomic profiling data were acquired by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Proteins were identified using a combination of database search tools and candidate proteins were selected based on Jonckheere-Terpstra trend analysis. Pathway analysis was performed using WebGestalt. In vitro model of human bronchial epithelial cell line treated with cigarette smoke condensate (CSC) was used for metabolic flux experiments by gas chromatography mass spectrometry (GC MS) analyses.
We identified 2901 proteins in bronchial epithelial cells from risk stratified individuals. Jonckheere-Terpstra trend test resulted significantly altered expression of 315 proteins (trend p <0.05) with 238 up and 77 down trends. KEGG pathway analysis with the 315 proteins revealed very early events of possible metabolic reprogramming in the cytologically normal bronchial epithelium of individuals at high risk for lung cancer development. Fourteen enzymes of the glycolytic pathway, TCA cycle, pentose phosphate pathway, and glycogenolysis were over expressed. Six of these fourteen enzymes, PYGB, PFKP, PFKL, PKM2, IDH1, and IDH2 were rate limiting enzymes. In in vitro culture of human bronchial epithelial cells treated with CSC, lactate production and glucose consumption were increased suggesting Warburg effect and metabolic reprogramming. Evidence of glutamine metabolism through reductive carboxylation in CSC treated cells was obtained from the metabolic flux analyses of cells from this in vitro model. Contribution of labeled carbon from [U-C5]-glutamine to TCA cycle in CSC treated cells were more than untreated control cells and there was strong M+5 citrate labeling in CSC-treated cells.
Shotgun proteomic analysis of cytologically normal bronchial epithelial cells in individuals at increasing risk for lung cancer revealed over expression of carbohydrate metabolic enzymes in high risk individuals suggesting possible metabolic reprogramming. The altered profile of metabolic enzymes may provide a signature of lung cancer risk assessment and serve as the basis of patient selection for surveillance programs and chemoprevention.