Chronic Exposure to Chewing Tobacco Induces Metabolic Reprogramming and Cancer Stem Cell-Like Properties in Esophageal Epithelial Cells

Abstract

Tobacco in its smoke and smokeless form are major risk factors for esophageal squamous cell carcinoma (ESCC). However, molecular alterations associated with smokeless tobacco exposure are poorly understood. In the Indian subcontinent, tobacco is predominantly consumed in chewing form. An understanding of molecular alterations associated with chewing tobacco exposure is vital for identifying molecular markers and potential targets. We developed an in vitro cellular model by exposing non-transformed esophageal epithelial cells to chewing tobacco over an eight-month period. Chronic exposure to chewing tobacco led to increase in cell proliferation, invasive ability and anchorage independent growth, indicating cell transformation. Molecular alterations associated with chewing tobacco exposure were characterized by carrying out exome sequencing and quantitative proteomic profiling of parental cells and chewing tobacco exposed cells. Quantitative proteomic analysis revealed increased expression of cancer stem cell markers in tobacco treated cells. In addition, tobacco exposed cells showed the Oxidative Phosphorylation (OXPHOS) phenotype with decreased expression of enzymes associated with glycolytic pathway and increased expression of a large number of mitochondrial proteins involved in electron transport chain as well as enzymes of the tricarboxylic acid (TCA) cycle. Electron micrographs revealed increase in number and size of mitochondria. Based on these observations, we propose that chronic exposure of esophageal epithelial cells to tobacco leads to cancer stem cell-like phenotype. These cells show the characteristic OXPHOS phenotype, which can be potentially targeted as a therapeutic strategy.

LncRNA LINC00467 acted as an oncogene in esophageal squamous cell carcinoma by accelerating cell proliferation and preventing cell apoptosis via the miR‐485‐5p/DPAGT1 axis

“…In detail, differentially expressed lncRNAs were generally involved in cellular processes of ESCC cells, suggesting that these lncRNAs could serve as potential diagnostic or therapeutic markers to evaluate the prognosis of ESCC patients 29–32 . Nevertheless, the pathology of ESCC was complicated, and the exploration of the mechanisms underlying ESCC progression was still finite 33 . In this study, we attended to investigate the malignant biological behavior and molecular mechanism of LINC00467 associated with ESCC development.…”

Temporal Quantitative Proteomics Reveals Proteomic and Phosphoproteomic Alterations Associated with Adaptive Response to Hypoxia in Melanoma Cells

“…The phosphopeptide-enriched samples as well as the total proteome samples were analysed on an Orbitrap Fusion Tribrid mass spectrometer (Thermo Electron, Bremen, Germany) coupled to a nanoAcquity UHPLC (Waters, Milford, MA, USA) as described earlier [ 58 ]. The LC settings for both total proteome and phosphoproteome were identical: The peptide samples were first loaded onto an Acquity UPLC M-Class V/M symmetry trap column (Waters, Milford, MA, USA) at a flow rate of 5 µL/min, and then resolved on an Acquity UPLC M-Class Peptide BEH C18 nanoAcquity column (Waters, Milford, MA, USA) over a runtime of 120 min at a flow rate of 300 nl/min.…”

Smokeless Tobacco and Its Ill-Effects: Recent Literature Update

“…A study led by Datta et al aimed at assessing the microscopic and the phenotypic changes in the oesophageal human cell lines. 22 In this study, oesophageal cell lines were treated with chewed tobacco for 8 months. They observed progressive increase in proliferative ability of cells and also increased invasive capabilities with increased duration of exposure to chewed tobacco.…”