CTSD and colorectal carcinoma: Mechanistically, we found that acetate promotes LMP and the consequent release of cathepsin D (CatD), but not of cathepsins B or L. We described a novel anti-apoptotic role for this lysosomal protease [13,14], which is often overexpressed in CRC [16,17], since we found that acetate-induced apoptosis of CRC cells was enhanced by the inhibition of CatD, either with siRNA or pepstatin A (PstA), which was associated with higher mitochondrial dysfunction and increased mitochondrial mass [14].