Spatiotemporal control of SMARCA5 by a MAPK-RUNX1 axis distinguishes mutant KRAS-driven pancreatic malignancy from tissue regeneration (ATAC-Seq)

De-differentiation or trans-differentiation is a common response to injury in many tissues, and the processes predispose cells to cancer. Acute pancreatitis-induced acinar-to-ductal metaplasia (ADM) is similar to pancreatic ductal adenocarcinoma (PDAC) at both the chromatin level and gene expression level. Mutant KRAS induces chromatin remodeling activities required for both regeneration and tumorigenesis at the peak of ADM, and it blocks regeneration. We show that chromatin remodeler SMARCA5 (SNF2H) can promotes the regeneration defects caused by mutant KRAS by maintaining chromatin accessibility at regions specifically required for malignancy. Mechanistically, regeneration-related chromatin remodeling activities are shared between wild-type and mutant KRAS and they occur very early upon pancreatitis, while the malignancy-related chromatin regions become accessible much later. The activity of SMARCA5 is controlled spatiotemporally by transcription factor RUNX1, which is only accumulated at sufficient levels at late ADM lock-in stage. Finally, we show that the malignancy regulation activity of SMARCA5 is different from its general function in CTCF recruitment. In summary, we have identified a specific function of a general chromatin remodeler that is precisely controlled during acinar cell trans-differentiation to separate malignancy from tissue regeneration.