In vitro combinatorial anti-proliferative and immunosuppressive effects of Brucea javanica extract with CX-4945 and imatinib in human T-cell acute lymphoblastic leukemia cells.

Since 1970, the isolated and identified components of Brucea javanica (L.) Merr. have been known to contain anticancer effects, particularly antileukemic effect. In this study, the inhibitory effect of Brucea javanica (BJ) on cell growth and inflammation was confirmed in human T-cell acute lymphocytic leukemia (T-ALL) cells, and its efficacy as an antileukemic agent was verified. Our results showed that BJ extract induced caspase-dependent apoptosis of T-ALL Jurkat cells through inhibition of the CK2-mediated signaling pathway, while exerting no significant cytotoxicity in normal peripheral blood mononuclear cells. Moreover, BJ extract suppressed the NF-κB signaling pathway, thus, inhibiting the interleukin (IL)-2 expression induced by phorbol 12-myristate 13-acetate (PMA) and phytohemagglutinin (PHA). Notably, combined treatment with BJ extract plus CX-4945 or imatinib exerted enhanced inhibitory effects on T-ALL cell growth and IL-2 production. Overall, these results suggest that BJ extract can be a potent therapeutic herbal agent for T-ALL treatment and prevention of IL-2 mediated inflammatory immune responses.