Assays were conducted at neutral pH in the culture medium to assess whether CatS could degrade recombinant occludin as well as archetypal adhesion/junction proteins, including claudin-3; E-cadherin, which was identified as a CatS substrate in a mouse model of pancreatic cancer [41]; and JAM-B, which was proposed as a CatS target promoting blood–brain barrier transmigration during brain metastasis [42]. Here, CLDN3 is linked to pancreatic neoplasm.