Journal: PLoS ONE
Article Title: Desmoplasia and oncogene driven acinar-to-ductal metaplasia are concurrent events during acinar cell-derived pancreatic cancer initiation in young adult mice
doi: 10.1371/journal.pone.0221810
Figure Lengend Snippet: (A) Histochemical visualization of HA (brown) counterstained with hematoxylin (blue). Representative micrographs depict the pancreata of KPT and KP mice 1 month, 2 months, and 3 months post-tamoxifen injection. Images of KPT pancreata depict dysplastic regions containing ADM and/or PanIN. Masson’s trichrome staining depicting collagen deposition (blue) in serial sections from the same KPT pancreata as shown in (A) , n = 7 for KP mice, n = 4 for 1M KPT mice, n = 6 for 2M KPT, n = 6 for 3M KPT. Magnification of bright field images is 20X. (B) Representative multiplexed IF micrographs for detection of nuclei (DAPI, blue), αSMA (white), CK19 (red), and Cpa1 (green). Rows depict healthy acinar tissue (acinar), a region of ADM and PanIN lesions. Micrographs are representative of the pancreata of KPT mice 2 months post tamoxifen treatment ( n = 3), magnification is 63X. All scale bars represent 100 μm.We sought to identify the source of HA in regions of ADM, via the detection of activated PSC. Increased activation and proliferation of PSC are directly involved in the development of PDAC associated fibrosis via the deposition of ECM components including HA and collagen in the tumor microenvironment . Multiplexed IF staining against αSMA, CK19 and Cpa1 revealed the presence of activated PSC in proximity to PanIN lesions and infiltrating regions of ADM in KPT mice. Activated αSMA-positive PSCs were not observed in regions of Cpa1 + /CK19 - healthy acinar tissue ( Fig 5B , top panel). Activated PSC were observed infiltrating regions of ADM containing Cpa1 + /CK19 + cells undergoing ADM ( Fig 5B , middle panel), and CK19 + /Cpa1 - PanIN lesions were surrounded by activated PSC ( Fig 5B , bottom panel). These observations indicate that PSC recruitment and/or activation occur during ADM and that neoplasia-associated HA production and PSC activation precede collagen deposition, which is associated with PanIN lesions. To our knowledge, the role of desmoplasia in general, or HA deposition specifically, in the initiation of PDAC has not been investigated in detail, due to the paucity of animal models. While PSC activation in regions of ADM is associated with HA deposition, additional experiments are necessary to definitively identify the specific cellular origin of HA in regions of ADM. These results establish the KPT model as an ideal model to study the role of the desmoplastic response in PDAC development from a defined population of adult cells.
Article Snippet: Primary antibodies were diluted in PBS-T and used at the following concentration CK19 1/20 (DSHB Cat# TROMA-III, RRID:AB_2133570), Cpa1 1/1000 (R&D Systems Cat# AF2765, RRID:AB_2085841), Sox9 1/5000 (Millipore Cat# AB5535, RRID:AB_2239761), αSMA 1/200 (Thermo Fisher Scientific Cat# 14-9760-80, RRID:AB_2572995), mCherry 1/50 (Rockland Cat# 600-401-379, RRID:AB_2209751).
Techniques: Injection, Staining, Activation Assay