The role of SLC7A11 in arsenite-induced oncogenic phenotypes of human bronchial epithelial cells: A metabolic perspective.

Chronic arsenic exposure enhances the probability of lung cancer with the underlying mechanisms remain unknown. Glutamine-driven synthetic metabolism, including nucleotide synthesis, amino acid production, TCA cycle replenishment, glutathione synthesis, and lipid biosynthesis, is crucial for both cancer initiation and progression. This study demonstrated that chronic exposure to 0.1 μM arsenite for as long as 36 weeks induced malignant transformation in human bronchial epithelial cells (BEAS-2B). Metabolomics were used to systematically disclose metabolic characteristics in arsenic-transformed malignant (As-TM) cells. Significantly changed metabolites were enriched in alanine, aspartate and glutamate metabolism, arginine biosynthesis, glutamine and glutamate metabolism, glutathione metabolism, butanoate metabolism, TCA cycle, and arginine and proline metabolism. It is worth noting that glutamate located at the intersection of the enriched metabolism pathways. Glutamine deprivation attenuated the oncogenic phenotypes, including capacity of wound healing and proliferation, in As-TM cells. And the expression levels of mRNA and proteins associated with glutamine metabolism-related transporters and enzymes, including SLC7A11, GCLM, and GCLC, were significantly increased, with SLC7A11 exhibiting the most substantial increase. Moreover, arsenite transformation progressively elevated SLC7A11 mRNA and protein levels over time. The SLC7A11 inhibitor sulfasalazine remarkably attenuated arsenite-induced oncogenic phenotypes. Collectively, our data suggest that chronic arsenite exposure enhances glutamine metabolism through upregulation of SLC7A11, thereby promoting cell proliferation and malignant transformation. These results provide new insights for preventive and therapeutic strategies for lung cancer linked to arsenic exposure.