Treatment of melanoma cells with DC661 induced the accumulation of the autophagic vacuole marker LC3B-II, which was more pronounced and lower than that of Lys05 or HCQ. At concentrations of it greater than 10 μM, all cells died. Compared with HCQ and Lys05, DC661 inhibited autophagic flux more significantly in melanoma cells expressing the mCherry-eGFP-LC3B reporter gene; in melanoma cells expressing the GFP-LC3B reporter gene, the expression level was higher of free GFP levels. It can cause a more pronounced lysosomal deacidification effect. In a variety of cancer cell lines, including colon and pancreatic cancer cells, the IC50 of DC661 was 100-fold lower than that of HCQ as measured by MTT assay after 72 hours of drug incubation. In BRAF-mutated melanoma cell lines, it inhibited the clonal growth of long-term melanoma cells more effectively and induced more apoptosis than Lys05, HCQ or BRAF/MEK dual inhibition conditions.
