Proteomic profiling of CD133 + and CD326 + (EpCAM) subpopulations in A549 cells: insights into pluripotency and tumor heterogeneity.

[OBJECTIVE] This study aimed to isolate different cancer cell populations and characterize their secretome profiles to better understand their functional roles in metastasis and tumor progression. For this purpose, we analyzed the secretomes of CD133 and CD326 (EpCAM) positive subpopulations derived from the A549 cell line.

[METHODS] CD133 positive (cancer stem cell marker) and CD326 positive (pluripotent stem cell marker) cells were isolated from the A549 non-small cell lung cancer cell line using magnetic cell separation. Secretome proteins from these subpopulations, along with parental A549 cells, were analyzed using bottom-up proteomics via liquid chromatography-tandem mass spectrometry (LC-MS/MS). The resulting datasets were further evaluated through bioinformatics analyses.

[RESULTS] CD133 positive cells were associated with angiogenesis, mesenchymal stem cell differentiation, and enhanced cell migration. In contrast, CD326 positive cells demonstrated pluripotent characteristics linked to epithelial-mesenchymal transition, neuronal differentiation, and placental morphogenesis, indicating a potential role in metastatic processes. Additionally, SERPINE2 and ADAM10 were identified as potential biomarkers for lung cancer, while YWHAZ and TRIM28 were associated with pluripotent cancer stem cell phenotypes.

[CONCLUSION] These findings support the existence of distinct cancer stem cell subtypes exhibiting multipotent and pluripotent properties. Secretome profiling provides valuable insights into tumor heterogeneity and highlights novel biomarker candidates, offering potential avenues for improved diagnosis and targeted therapeutic strategies in lung cancer.