Abstract 5059: Cancer cell invasion dynamics in microchannels during stromal cell coculture

Abstract

Abstract Metastasizing cancer cells must escape their tumor microenvironment and invade into surrounding healthy stromal tissue. During this process, they must balance intercellular crosstalk with ECM degradation, physical force generation, and cytoskeletal rearrangement. To mimic this process in vitro, PDMS microchannels fabricated with photolithography and replica molding were used to examine the interaction of cancer cells with healthy stromal cells during physical confinement in three dimensional environments. A focus was placed on understanding the variations in invasion behavior between healthy cells and cancer cells, then attempting to explain these differences by cell mechanical properties and gene expression. Distinct differences in cancer cell invasion characteristics were observed between wide 10 μm channels and narrow 3 μm channels, with the latter exhibiting smooth velocity profiles and increased channel permeation. Live cell actin staining, ECM protein alteration, and chemical inhibition of both Rac1 and RhoA mechanical pathways were all used to better understand these differences, leading to the conclusion that the actin cytoskeleton is greatly altered during invasion into very confined channels. To better understand the role of stromal cells in this process, both indirect and direct coculture of MDA MB-231 basal breast cancer cells and stromal cells were performed in microchannel chips with the aid of live cell permeable tracking dyes. To reflect a diverse range of stromal cell types, cocultures were performed with MCF 10A non-tumorigenic breast epithelial cells, macrophage-differentiated THP-1 monocytes, and HN-CAFs (head and neck carcinoma-associated fibroblasts). Both the cancer cells and the stromal cells exhibited increases in invasion speed upon direct co-culture of the two cancer cell lines, both in wide and narrow channels. The use of stromal cell-conditioned media as well as observed differences in migration speed and persistence when unconfined provided further understanding of the complex processes underlying cancer cell and stromal cell invasion. Citation Format: Andrew W. Holle, Verena Kast, Ralf Kemkemer, Joachim Spatz. Cancer cell invasion dynamics in microchannels during stromal cell coculture. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 5059.