Figure 7
Microscopic images of in vitro epithelial cysts exhibiting characteristics of early-stage epithelial glandular tumor. (A-B) Loss of PALS1 expression results in the disruption of MDCK cell polarity and impaired development of cyst lumen [33]. PALS1 is involved in the establishment of cell polarity. Cysts composed of PALS1-ablated cells exhibited multiple small lumens (A) or developed a larger but incomplete lumen (arrow in B). (C-D) Overexpression of ErbB2 receptor leads to the formation of multi-acinar structures with filled lumens in 3D Matrigel [34]. (C) The structures consisted of multiple acinar-like units with filled lumens. The size range of at least 200 structures is shown. (D) Optical section of a single structure along the z-axis. (E-F) Inhibition of luminal apoptosis in proliferating structures results in lumen filling [3]. MCF-10A cells were infected with retroviruses encoding expression of proliferative oncoproteins--cyclin D1 or human papilloma virus (HPV) 16 E7--and anti-apoptotic Bcl family proteins (Bcl-2 or Bcl-XL). (E) Acinar structures formed by cells expressing HPV 16 E7 and Bcl-2. (F) Structures formed by cells expressing cyclin D1 and Bcl-XL. Panels A-B were reproduced with permission from [33]© The American Society for Cell Biology. Panels C-D were reproduced with permission from [34]© Nature Publishing Group. Panels E-F were reproduced with permission from [3]© Nature Publishing Group.