Cystemustine is a DNA inhibitor that induces DNA cross-linking, thereby preventing tumor cell proliferation. It exerts cytotoxic effects by disrupting the cell cycle, inducing cell redifferentiation, and altering phospholipid metabolism. Cystemustine shows high antitumor activity and a short plasma half-life in mice, influenced by the timing of administration. It is applicable in research on various malignancies, including melanoma, glioma, renal cancer, head and neck cancer, and colorectal cancer.

Cystemustine (100, 200 μM, 2 h) does not cause DNA damage when used alone, but significantly increases DNA damage in M3Dau cells when combined with BNAG. At 50 μM for 4 hours, Cystemustine induces cytotoxicity in M4Beu cells, and this effect is enhanced when combined with lGgBZ [an O6-alkylguanine-DNA alkyltransferase inhibitor].

Cystemustine administered at 35 mg/kg intravenously with a single dose over 55 days exhibits significant circadian variations in toxicity, with the minimal toxicity occurring 15-19 hours after light onset and the peak toxicity at 7 hours. When administered at 15 mg/kg either intravenously or directly into tumors from days 1 to 19 in a murine melanoma model, Cystemustine induces changes in cellular morphology, cell cycle, and melanin content. Additionally, direct intratumoral injection of 15 mg/kg from days 11 to 18 leads to a novel phospholipid metabolic phenotype in melanoma tumors in the mouse model.