DDR1 and pancreatic ductal adenocarcinoma: Moreover, the cleavage of COL1 by MMPs differently affects the bioenergetics and growth of pancreatic ductal adenocarcinoma via DDR1: matrix-metalloprotease-cleaved COL1 (cCOL1) activates a signaling cascade that promotes tumor growth, while intact COL1 (iCOL1) induces DDR1 degradation, resulting in opposite effects.