Treosulfan (Treosulphan, NSC 39069, AbMole, M13635) is an alkylator that undergoes non-enzymatic hydrolysis under physiological conditions to generate active metabolites, exhibiting significant cell proliferation inhibitory effects. It serves as a critical tool in various tumor models and hematopoietic stem cell transplantation studies. The chemical structure of treosulfan features a six-carbon sugar alcohol backbone, in which four hydroxyl groups are methylated, the hydroxyl group at the C2 position is substituted with a sulfhydryl group, and sulfate ester groups are attached to the C1 and C4 positions, respectively. This structural design imparts chemical stability under neutral pH conditions, whereas hydrolysis occurs under weakly acidic environments: the sulfate ester groups are first removed to generate an intermediate monoepoxide derivative (EBDM), which subsequently undergoes spontaneous cyclization to form the electrophilic diepoxide metabolite (DEB). This activation process does not require enzymatic catalysis. As the ultimate active form of treosulfan (NSC 39069), DEB attacks nucleophilic sites (primarily the N7 position of guanine) in DNA molecules, forming intra- and interstrand crosslinks. These crosslinks distort the DNA double helix, impede the normal functions of DNA polymerases and topoisomerases, and ultimately induce S-phase cell cycle arrest and activation of apoptotic pathways. Compared to traditional nitrogen mustard alkylating agents, the diepoxide structure of treosulfan exhibits higher DNA crosslinking efficiency, with IC₅₀ values reaching micromolar or even nanomolar levels in various tumor cell lines.

Treosulfan (Treosulphan, AbMole, M13635) has garnered extensive attention in the field of hematopoietic stem cell transplantation. Treosulfan effectively eliminates host hematopoietic cells while causing minimal damage to non-hematopoietic tissues. For instance, in NOD/SCID mouse models, preconditioning with treosulfan (CAS No.: 299-75-2) (1.5 g/kg/day for 3 days) significantly improves the engraftment success rate of CD34⁺ cells. Beyond hematologic malignancy research, treosulfan (NSC 39069) is also applicable to cell- and animal-level studies of other tumors. For example, treosulfan in combination with fludarabine synergistically kills ovarian cancer cell lines SKOV3 and OVCAR4 ^[1]. In an Ewing’s sarcoma A673 cell xenograft model, intraperitoneal injection of treosulfan (150 mg/kg, twice weekly) reduces tumor volume by 64% while downregulating the expression of ETS fusion genes ^[2].

References and Acknowledgments

[1] I. El-Serafi, I. Micallef Nilsson, A. Moter, et al., Impact of fludarabine and treosulfan on ovarian tumor cells and mesothelin chimeric antigen receptor T cells, Cancer immunology, immunotherapy : CII 73(9) (2024) 163.

[2] Sebastian Werner, Arnulfo Mendoza, Ralf A Hilger, et al., Preclinical studies of treosulfan demonstrate potent activity in Ewing’s sarcoma, 62(1) (2008) 19-31.