RBC8 is a specific GTPases RalA/RalB inhibitor by inhibiting the binding of Ral to its effector RALBP1, no inhibition on the GTPases RhoA and Ras.

GTPase (H2122 cells):3.5 μM, Ral GTPase (H358 cells):3.4 μM

在负荷H358异种移植物的小鼠体内,RBC8（50 mg/kg,i.p.）可特异性抑制RalA和RalB,从而抑制肿瘤生长.

在活细胞中,RBC8k可诱导RalB–GDP中化学位移改变从而降低RalA的活化作用。在Ral依赖性H2122（IC50：3.5 μM）和H358（IC50：3.4 μM）中,RBC8引起anchorage-非依赖性生长抑制。

Growth inhibition of human lung cancer cells by the compounds is measured under anchorage-independent conditions in soft agar. Cells are seeded into 6-well plates (coated with a base layer made of 2.0 ml of 1% low-melting-point agarose) at 15,000 cells per well in 3.0 mL of 0.4% low-melting-point agarose containing various concentration of drug. Two to four weeks (depending on the cell line) after incubation, the cells are stained with 1.0 mg ml?1 nitroblue tetrazolium, and colonies are counted under a microscope. The IC50 values are defined as the concentration of drug that resulted in a 50% reduction in colony number compared with the DMSO-treated control. (Only for Reference)