PMC

Examples of immunofluorescent images of insulin (A, B) and endocrine cocktail (C, D) immunoreactivity in islets or as clustered cells in four different pancreas sections of non‐pregnant and pregnant cases. Merged images showing insulin in white (A and B) and endocrine cocktail in green (C and D) with DAPI in blue (all images). Yellow arrows indicate clustered β‐cells and white arrows indicate clustered endocrine cocktail cells in both non‐pregnant and pregnant cases. There was no change in frequency of total clustered endocrine cells (of total endocrine cells counted in all compartments of pancreas) in pregnancy (3.8 ± 0.7 vs. 3.5 ± 0.5% of clustered endocrine cells, Pregnant vs. non‐pregnant, p = ns) (E). Frequency of clustered β‐cells (of total clustered endocrine cells) was higher in pregnant cases compared to non‐pregnant cases (46.6 ± 5.0 vs. 31.8 ± 5.0% of clustered β‐cells, pregnant vs. non‐pregnant, p < .05) (F). The frequency of clustered endocrine cocktail cells (of total clustered endocrine cells) was lower in pregnant cases compared to non‐pregnant cases (57.02 ± 6.8 vs. 36.2 ± 4.02% of clustered endocrine cocktail cells, pregnant vs. non‐pregnant, p < .01) (G). Scale bar, 100 μm (all images)

(A-E) PECAM-1 staining of endocrine hormone-negative EGFP-positive islet cells. Pancreas sections from ERTF-Pdx1-EGFP mice 10 weeks after Dox withdrawal were stained with the anti-GFP antibody (green), anti-PECAM-1 antibody (light blue), a mixture of antibodies against the endocrine hormones insulin, glucagon, PP, and somatostatin (red), and DAPI (blue). Single staining views and merged views are shown. Arrowhead indicates an endocrine hormone-negative EGFP-positive islet cell, which was also negative for PECAM-1, suggesting that it was not from the endothelial lineage. Arrows indicate endocrine hormone-negative EGFP-negative islet cells. These cells were positive for PECAM-1, suggesting that they were from the endothelial lineage. Bar = 50 μm. (F-J) Pancreas sections from ERTF-Pdx1-EGFP mice with Dox (F) and without Dox for 10 weeks (G-J) were stained with the anti-GFP antibody (green) (H, J), anti-Nkx6.1 antibody (light blue), a mixture of antibodies against the endocrine hormones insulin, glucagon, PP, and somatostatin (red), and DAPI (blue). Arrows indicate endocrine hormone-negative EGFP-positive Nkx6.1 positive islet cells. No endocrine hormone-negative Nkx6.1 positive islet cells were seen when Dox treatment was continued (F). Bar = 50 μm.

Both endocrine sensitive and resistant breast cancer cells express all components of the RET signaling pathway, but endocrine sensitive breast cancer cells lack GDNF to initiate the resistance pathway. By contrast, endocrine resistant cells secret GNDF, which acts in an autocrine or paracrine fashion to promote endocrine resistance in nearby cells.

a Syt13 localizes to the apical PM in polarized MDCK cells. b Western blot showing the close proximity of Syt13 with different apical proteins in MDCK cells. c Surface biotinylation assay showing Syt13 localization to the plasma membrane. d Apical localization of Syt13 full-length and the C2 truncated variants. e Quantification of apical localization of Syt13 protein variants. n = 4 independent experiments for d and e. f Scheme of positioning of an epithelium-residing endocrine precursor and an egressing endocrine cell. Distal (front) and proximal (rear) domains to the central lumen are defined in egressing endocrine cells. Created with BioRender.com. g Syt13 localizes to the apical PM (arrowhead) in differentiated endocrine cells fully residing within the pancreatic epithelium. Syt13 localizes at the front domain (arrowheads) of endocrine cells that are not in direct contact with the epithelial lumen in 3D epithelial cysts (h) and in vivo (i). j Pancreatic section showing the expression of aPKC at the front domain (arrowhead) of egressing endocrine cells. k Quantification of Syt13 and aPCK expression at the distal and proximal domains of newly formed endocrine cells. For Syt13, n = 54 endocrine cells from five independent pancreata (i and k). For aPKC, n = 38 endocrine cells from four independent pancreata (j and k). (l) Quantification of aPCK expression at the distal and proximal domains of newly formed endocrine cells in control and Syt13 KO pancreatic sections. For control, n = 43 endocrine cells from 4 independent pancreata. For KO n = 36 endocrine cells from three independent pancreata. m Binding of purified Syt13-C2AB protein variant to 100 nm sized LUVs containing different species of phosphatidylinositol phospholipids (POPC/cholesterol/phosphoinositide 65/30/5 mol %) assessed by electrochemiluminescence-based immunoassay (EIA). n = 3 independent experiments. n, o Treatment of explant culture of E13.5 Ngn3^Cre/+; ROSA26^mTmG/mTmG pancreata with PIP3 inhibitor PIT-1 for 48 h impairs endocrine cell egression. n = 3 independent experiments. Arrowheads indicate endocrine cells. L lumen. Scale bar 10 µm (d, g–j); 20 µm (a, n). Representative pictures from 2 (b, c) and 3 (a, g, h) independent experiments. Tukey’s multiple comparisons test (e) and two-sided t-test (k, l, o) were used for statistics. Data are represented as mean ± SD. Source data are provided as a Source Data file.