3-Chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX) induces gene mutations and inhibits metabolic cooperation in cultured Chinese hamster cells.

Investigations were carried out on 3‐chloro‐4‐(dichloromethyl)‐5‐hydroxy‐2(5H)‐furanone (MX), a potent direct‐acting bacterial mutagen found in chlorinated tap water, for the potential to induce 6‐thioguanine (6‐TG) resistant mutations in cultured Chinese hamster V79 cells. The mutagenicity of MX was manifested when cells were treated with MX in Hanks balanced salt solution, but not in serum‐free Eagle's minimal essential medium. A 12‐fold higher mutation frequency over control was obtained at 12.5 μg/ml MX. In addition, the inhibitory effect of MX on metabolic cooperation between cocultivated 6‐TG‐sensitive (6‐TG5) and ‐resistant (6‐TG1) V79 cells was investigated. Recovery of 6‐TG1 cells significantly increased at 0.8–2.0 μg/ml MX due to impaired intercellular communication with 6‐TGs cells. MX is believed to exert tumor‐promoting and mutagenic activity in mammalian cells.