Fig. 5.

Tumor cell in vitro intravasation in the heterogeneous ECM with various degree of local collagen fiber alignment. (A) The distribution of invading tumor cells in the sandwiched ECM after 96 h (B, 1–3 and C, 1–3). Enlarged Insets respectively show the bright field and fluorescent images of the spatial distribution and morphology of cells invading in the Matrigel region (B, 1 and C, 1), the aligned collagen region (B, 2 and C, 2), and the randomly oriented collagen region (B, 3 and C, 3). The Insets in C, 1–3 illustrate the magnifications of the corresponding areas, representing alignments of the cell nucleus (vertical, random, and horizontal alignment, as indicated by arrows). (D, 1–3) The quantitative analysis of cell orientation distributions in the aforementioned corresponding regions.