NNMT and cancer: DNMT1 inhibition and NNMT activation render OXPHOS‐sensitive cancer cells resistant in vitro (Figure 4E–M); we thus further examined the effects of S‐Gboxin and Berberine on tumor xenografts by NCI‐H82 cancer cells with NNMT overexpression and DNMT1 knockdown (NCI‐H82‐OE‐NNMT/sh‐DNMT1).