Abstract
For studying cellular communications ex-vivo, two-dimensional (2D) cell culture model currently is widely used as the golden standard, such as, examining exosome RNA expression profiles from tumor cells and tumor biomarker discovery. Although the 2D culture system is simple and easily accessible, the culture environment is unable to represent the in vivo extracellular matrix (ECM) microenvironment. Our study observed that 2D culture derived exosomes showed significantly different profiles in terms of secretion dynamics and essential signaling molecular contents (RNAs and DNAs), compared to the 3D culture derived exosomes. By using the next-generation sequencing of cervical cancer cells and cervical cancer patient plasma-derived exosomal RNA, we observed that 3D culture derived exosomal RNAs may undergo specific sorting process and differ from their parent cells. Most importantly, the 3D culture derived exosomal RNA profile exhibited a much higher similarity (~96%) to in vivo circulating exosomes from cervical cancer patient plasma. However, 2D culture derived exosomal RNA profile is irrelevant and only correlated to their parent cells cultured in 2D. On the other hand, DNA sequencing analysis suggests that culture and growth conditions do not affect the genomic information carried by exosome secretion. This work also suggest that tackling exosomal molecular contents and alterations secreted into interstitial fluids can provide an alternative, non-invasive approach for investigating 3D tissue behaviors at the molecular precision. This work could serve as a foundation for building precise model employed in mimicking in vivo tissue system with exosomes as the molecular vehicle for investigating tumor biomarkers, drug screening, and understanding tumor progression and metastasis.
