Inhibition of Lkb1 results in pancreatic cystic neoplasias but not polarity defects. (A) Lkb1^WT/WT (top) and Lkb1^MG/MG (bottom) E12.5 pancreatic explants were cultured on transwell filters for 3 DIV with 1 µM 1NMPP1. General pattern of growth and branching is visualized using Pdx1-GFP. (B) 1NMPP1-treated Lkb1^WT/WT (top) and Lkb1^MG/MG (bottom) E12.5 pancreatic explants show similar patterns of Muc-1, E-cadherin, and ZO-1 staining. (C) Lkb1^WT/WT (top) and Lkb1^MG/MG (bottom) E16.5 pancreatic explants were cultured with 1 µM 1NMPP1 for 3 d. Lkb1^MG/MG explants develop multiple fluid-filled cysts lined by Pdx1-expressing epithelial cells. Phase microscopy (left), hematoxylin-eosin stained sections (middle), and fluorescence microscopy of Pdx1-GFP–expressing explants (right). (D) 1NMPP1-treated Lkb1^WT/WT (top) and Lkb1^MG/MG (bottom) E16.5 pancreatic explants show similar patterns of Muc-1, E-cadherin, ZO-1, and actin staining. (E) E-cadherin and ZO-1 pattern of staining in a developing cyst (note: ZO-1 pattern is a projection across a 10-µm z-stack). Bars: (A) 500 µm; (B) 50 µm; (C) 1,000 µm (phase), 400 µm (fluorescence); (D) 10 µm; (E) 100 µm.