Interaction with adipocytes induces lung adenocarcinoma A549 cell migration and tumor growth

Adipocytes have been demonstrated to promote the progression of various tumors through modulation of cancer cell metabolism. However, their role in lung cancer progression remains undetermined. In the present study, adipocytes and lung adenocarcinoma A549 cells were cultured in a Transwell co-culture system. Cancer cells were additionally cultured in conditioned medium, obtained from adipocytes or co-cultured cells. A MTT and colony formation assay were performed to assess A549 cell proliferation. The expression of epithelial-mesenchymal transition protein markers E-cadherin and vimentin were measured by western blotting. A549 cell migration and invasion was determined with wound healing, Transwell and Matrigel assays. Oil Red-O staining was used to evaluate intracellular lipid content. Colorimetric assays were utilized to detect free fatty acid, glucose uptake, lactate production and triglyceride content in cells. The results revealed a reciprocal interaction between adipocytes and A549 cells, which significantly enhanced A549 cell proliferation and metastasis; whereas, the expression of E-cadherin was decreased and vimentin was increased in A549 cells. Additionally, A549 cells exhibited metabolic reprogramming in vitro following co-culture with adipocytes. It was demonstrated that lipid droplets accumulation, glucose consumption and lactate production increased in tumor cells exposed to adipocytes. Furthermore, adipocytes co-cultured with A549 cells exhibited a decrease in the number and size of lipid droplets, a decrease in the intracellular triglyceride content and a significant increase in the release of free fatty acids. These findings highlighted the crucial role of adipocytes in the modulation of lung adenocarcinoma A549 cell metabolism and suggested the involvement of adipocytes in lung cancer progression.