Figure 4.

Oncogenic perturbations and evolution of cancer-evocative morphology. Evolution of multicellular architecture consistent with cribriform (A–C), micropapillary (D–F), and high-grade (G–I) cancer morphology. The causal morphogenic defect is highlighted by a blue oval or circle in each cartoon. A: Misorientation of the mitotic spindle to lie parallel to the cell long axis (blue circle) induced inappropriate epithelial stratification (yellow cells) and generation of ectopic apical membrane foci (red) that become expanded by secretion to form multiple lumens. In combination, these phenomena promote development of back-to-back lumens bordered by atypical stratified epithelium. B: Cribriform morphology phenotype induced by mitotic spindle misorientation in three-dimensional Caco-2 organotypic. Staining DAPI for DNA, protein kinase C ζ (PKCζ) for apical membrane, and β-catenin for basolateral membranes. These features were evocative of cribriform colorectal cancer (CRC) morphology. C: Staining hematoxylin and eosin. D: Schematic shows that blockade of extracellular matrix (ECM):integrin receptor signaling (blue oval) impeded transcytosis, causing retention of apical membrane (AM) functional components at the ECM-facing basolateral membrane. Inverted multicellular polarity enabled outward secretion. E: Inverted polarity and expression of the AM marker podocalyxin (red), at the ECM-facing basolateral membrane in organotypic culture. The boxed area inset shows a high power view of podocalyxin accumulation at the basolateral membrane (yellow arrowhead). F: These features were evocative of micropapillary CRC morphology, stained by MUC1 immunohistochemistry. The Muc1 AM marker is localized on the ECM-facing exterior of cohesive cell nests, surrounded by clear lacunar spaces. In cancer cells, supernumerary centrosomes were common. G: Impaired clustering of extra centrosomes (blue oval) drove multipolar mitotic spindle formation. In a proportion of cells, these changes promoted multipolar division and pleomorphic progeny.⁴⁴H: Representative changes in three-dimensional organotypic culture of Caco-2 clones. Forced multipolar spindle formation (inset, shown at higher magnification) was accompanied by gross cellular and nuclear pleomorphism, dispersed apical membrane foci (red), and loss of glandular architecture. Genomically unstable cells with multipolar spindles frequently extend across the basement membrane:ECM interface. Staining DAPI for DNA; PKCζ for apical membrane, and α-tubulin for microtubules. These changes were evocative of high-grade CRC morphology. I: Loss of glandular architecture, cellular and nuclear pleomorphism, and atypical mitotic figure (inset, shown at higher magnification) at basement membrane:ECM interface in a high-grade CRC histological section. Staining hematoxylin and eosin. Scale bars: 20 μm (B, E and H). Original magnification: ×10 (C and F); ×20 (I).

Reprinted from Deevi¹⁰ et al with permission from Oncotarget (B); from Bryant et al⁹ with permission from Elsevier (E); and from Deevi et al¹¹ with permission from the Journal of Pathology (H).