HMOX1 and mantle cell lymphoma: In addition, pretreatment of SnPP led to a reduced autophagy formation in both REC-1 and BACH2KD Jeko cells (Fig. 3d, e), suggesting that the enhanced cytoprotective autophagy caused by decreased BACH2 is partly mediated by upregulation of HO-1 in BTZ-resistant MCL cells.