Novel NO-releasing scopoletin derivatives induce cell death via mitochondrial apoptosis pathway and cell cycle arrest

A series of phenylsulfonyfuroxan-based NO-releasing scopoletin derivatives were designed and synthesized in the study. All target compounds showed significantly improved antiproliferative activity against four cancer cell lines (MDA-MB-231, MCF-7, HepG2 and A459) and lower cytotoxicity toward normal liver LO2 cells. Derivative 47 concentration-dependently inhibited the colony formation of MDA-MB-231 cells. NO-releasing assessment indicated that the intracellular NO level was almost positively correlated with the antiproliferative ability. Compound 47, which released the highest amounts of NO, showed the best potency (IC₅₀ = 1.23 μM) against MDA-MB-231 cells. Mechanism research revealed for the first time that 47 blocked the proliferation of MDA-MB-231 cells by activating mitochondrial apoptosis pathway and arresting cell cycle at G2/M phase. Taken together, as a novel scopoletin derivative, 47 exhibited excellent inhibitory effects against malignant cancer cells and lower toxicity on normal cells. Thus, an in-depth evaluation of 47 to explore its complete therapeutic potential for cancer treatment is warranted.