Figure 2.

Nimbolide induces dose-dependent apoptosis in WM cells. (a and b) WM cell lines were treated with nimbolide at different concentrations for 6 h. Cell death was analyzed by annexin V staining followed by flow cytometry. Nimbolide induced apoptosis was dose dependent with maximum cell death at 1 μM, most notably in ibrutinib-resistant (BC/IR) cells (51% cell death). (c) Peripheral blood mononuclear cells from healthy human donors (n=3) were treated with indicated concentrations of nimbolide and stained with annexin V to assess apoptosis. Toxicity from nimbolide was minimal ranging between 0.15 and 4.7% of % control cell death, with the latter only seen at the highest concentration tested (1 μM). (d) Western blot analysis of WM cells treated with nimbolide at 0 and 1 μM confirms apoptosis by cleavage of caspases 3, 9 and PARP-1. All experiments were performed in triplicate. NS, Not statistically significant; **P<0.01. WM tumor cell lines: BC, BCWM.1; BC/IR, BCWM.1/IR; BC/BR, BCWM.1/BR; MW, MWCL-1; RP, RPCI-WM1