Sweroside eradicated leukemia cells and attenuated pathogenic processes in mice by inducing apoptosis

Acute myeloid leukemia (AML), characterized by extremely heterogeneous molecular and biologic abnormalities, is an aggressive hematologic malignancy, hampering the research and development of effective targeted treatment modalities. Sweroside (SWE), an iridoid glycoside, is isolated from Lonicera japonIca. It has diverse biological activities, but little is known in human leukemia. Here, our study showed the potential of sweroside as an effective agent against human leukemia using in vitro and in vivo approaches. Sweroside treatment obviously reduced the cell viability in human leukemia cell lines and primary human leukemia cells. S and G2/M cell-cycle arrest were induced by sweroside, associated with the down-regulation of Cyclin D1, cyclin-dependent kinase 4 (CDK4), CDC2 and CDC25 as well as the up-regulation of p53 and p21. In addition, apoptosis was highly induced by sweroside both in vitro and in vivo through enhancement of cleaved Caspase-3 and poly (ADP-ribosyl) transferase (PARP). Consistently, anti-apoptotic molecule of B cell CLL/lymphoma 2 (Bcl-2) was impeded by sweroside, while pro-apoptotic signal of Bcl-2-associated X protein (Bax) was elevated. In vivo, HL-60-bearing tumor growth was considerably inhibited by sweroside, which was related to proliferation suppression and apoptosis induction. Our study highlighted the therapeutic potential of sweroside, and provided new insights into the molecular mechanism of sweroside chemosensitization in human leukemia.