Inferring alterations in cell-to-cell communication in HER2+ breast cancer using secretome profiling of three cell
David J Klinke1, Yogesh M Kulkarni, Yueting Wu
1Department of Chemical Engineering and Mary Babb Randolph Cancer Center, West Virginia University, P.O. Box 6102, Morgantown, West Virginia; Department of Microbiology, Immunology, & Cell Biology, West Virginia University, Morgantown, West Virginia. david.klinke@mail.wvu.edu.
Abstract:
Challenges in demonstrating durable clinical responses to molecular-targeted therapies have sparked a re-emergence in viewing cancer as an evolutionary process. In somatic evolution, cellular variants are introduced through a random process of somatic mutation and are selected for improved fitness through a competition for survival. In contrast to Darwinian evolution, cellular variants that are retained may directly alter the fitness competition. If cell-to-cell communication is important for selection, the biochemical cues secreted by malignant cells that emerge should be altered to bias this fitness competition. To test this hypothesis, we compared the proteins secreted in vitro by two human HER2+ breast cancer cell lines (BT474 and SKBR3) relative to a normal human mammary epithelial cell line (184A1) using a proteomics workflow that leveraged two-dimensional gel electrophoresis (2DE) and MALDI-TOF mass spectrometry. Supported by the 2DE secretome maps and identified proteins, the two breast cancer cell lines exhibited secretome profiles that were similar to each other and, yet, were distinct from the 184A1 secretome. Using protein-protein interaction and pathway inference tools for functional annotation, the results suggest that all three cell lines secrete exosomes, as confirmed by scanning electron microscopy. Interestingly, the HER2+ breast cancer cell line exosomes are enriched in proteins involved in antigen-processing and presentation and glycolytic metabolism. These pathways are associated with two of the emerging hallmarks of cancer: evasion of tumor immunosurveillance and deregulating cellular energetics.
Insights
Cancer cells evolve by altering secreted biochemical cues to influence their survival. HER2+ breast cancer cells release exosomes enriched in proteins related to immune evasion and energy metabolism, supporting cancer
Area of Science:
- Cancer Biology
- Molecular Oncology
- Cellular Evolution
Background:
- Durable clinical responses to molecular-targeted therapies remain a challenge.
- Cancer is increasingly viewed as an evolutionary process driven by somatic mutations and cellular competition.
- Altered biochemical cues secreted by malignant cells may bias this fitness competition.
Purpose of the Study:
- To investigate if HER2+ breast cancer cells alter their secreted proteome to influence cellular fitness.
- To compare the secretome profiles of HER2+ breast cancer cell lines with a normal mammary epithelial cell line.
Main Methods:
- Proteomics workflow utilizing two-dimensional gel electrophoresis (2DE) and MALDI-TOF mass spectrometry.
- In vitro secretion analysis of two HER2+ breast cancer cell lines (BT474, SKBR3) and one normal mammary epithelial cell line (184A1).
- Exosome isolation and characterization via scanning electron microscopy, alongside protein-protein interaction and pathway inference for functional annotation.
Main Results:
- Secretome profiles of BT474 and SKBR3 cells were similar to each other but distinct from the 184A1 cell line.
- All three cell lines were confirmed to secrete exosomes.
- Exosomes from HER2+ breast cancer cells were enriched in proteins associated with antigen processing and presentation, and glycolytic metabolism.
Conclusions:
- HER2+ breast cancer cells exhibit distinct secretome profiles compared to normal cells.
- Cancer cell-derived exosomes are implicated in pathways linked to immune evasion and altered cellular energetics.
- These findings support the role of altered secreted factors in cancer evolution and hallmark acquisition.
