BECN1 and melanoma: Notably, in contrast to the results in rapamycin‐treated melanoma cells, OPTN inhibition significantly attenuated global autophagic flux in MUM2B cells, with a decreased LC3 II/I ratio, Beclin1 level and ATG5 level and increased p62 accumulation, which is in accordance with the metformin‐treated group (Figure S9C).