CS1 is a potent DNA Topo II α inhibitor that exhibits broad-spectrum antitumor effects in vitro, low toxicity in vivo, and potential anti-multidrug resistance capabilities. CS1 induces DNA damage, G2/M phase cell cycle arrest, and apoptosis [1].

CS1 exhibits cytotoxicity with IC50 values of 16.92 and 18.88 μM for MCF-7 and MCF7/ADR cells, respectively [1]. CS1 (10, 50, 100 μM) inhibits topoisomerase IIα (Topo IIα) activity [1] and shows antiproliferative effects in cancer cells at concentrations ranging from 0-20 μM [1]. Additionally, CS1 (2.5, 5, 10 μM) induces G2/M phase cell cycle arrest and apoptosis [1], and at concentrations of 5, 10, and 15 μM for 24 hours, it causes DNA breaks in MDA-MB-231 cells [1]. Cell cycle analysis with MDA-MB-231 cells at 2.5, 5, and 10 μM concentrations revealed G2/M phase arrest, while apoptosis analysis showed induction of apoptosis [1].

CS1, administered intravenously at a dosage of 20 mg/kg every other day for two weeks, demonstrated antitumor activity [1]. This was observed in an animal model using five-week-old female athymic nude mice (BALB/c-nu) [1].