Pancreatic cancer (PC) is highly lethal, with a five-year survival rate of only ~13%. PC is characterised by progressive cancer-associated fibrosis. We and others have shown that targeting cancer fibrosis can improve chemotherapy efficacy and impair metastasis in pre-clinical models (1-4). As such, we aimed to use proteomics to dissect the matrix signatures of pancreatic tumours from the highly-metastatic KPC (Pdx1-Cre; LSL-KrasG12D/+; LSL-Trp53R172H/+) and poorly-metastatic KPflC (Pdx1-Cre; LSL-KrasG12D/+; Trp53fl/+) mouse models, with an aim to identify new fibrotic drivers in metastatic cascade of this deadly disease (5).
We collected pancreatic tissue from KPflC, KPC and wildtype (WT) controls at early (~50 days), mid (~90 days) and late-stage disease (~200 days), enriched them for matrix proteins using ISDoT de-cellularisation and analysed them using data independent acquisition liquid chromatography-tandem mass spectrometry (DIA LC-MS/MS) (5).
DIA LC-MS/MS revealed an increased abundance of nidogen-2 (NID2) in KPC tumours compared to KPflC (5). 3D organotypic matrices generated with NID2 CRISPR-interference (CRISPRi) CAFs had reduced fibrosis, shown via second harmonic generation (SHG) imaging and Picrosirius Red/birefringence analysis (5). Organotypic invasion assays revealed that reduction of CAF NID2 significantly impeded the invasion of cancer cells (5).
Subcutaneous and orthotopic co-seeding experiments using NID2 CRISPRi CAFs with cancer cells showed that NID2 inhibition impeded tumour growth and fibrosis (5). Intravital (in vivo) imaging with quantum dots revealed improved vascular patency in NID2 knockdown tumours, with improved response to chemotherapy (5). Strikingly, in orthotopic models, mice bearing NID2 CRISPRi tumours had reduced liver metastasis and increased median survival, revealing NID2 as a potential new stromal co-target in this aggressive disease (5).