Figure 1. MLS-2438 suppresses viability of human melanoma cells and tumor growth in a mouse xenograft model. (A) structure of MLS-2438. Indirubin molecule was derivatized with a bromo-group at the 7-position on one indole ring and a hydrophilic group at the 3′-position on the other indole ring. The synthesis of this 7-bromoindirubin derivative was reported previously.³¹ (B) A2058, A375, G361 and MeWo human melanoma cells were treated with MLS-2438 at various concentrations for 24 h. Viable cells were counted by using a cell viability analyzer. The values of cell viability were calculated as percentages of viable cell numbers from bromoindirubin-treated cells to viable cell numbers from the DMSO-treated cells. (C) MLS-2438 suppressed tumor growth of MeWo human melanoma xenografts in NSG mice. (D) Body weight change. MLS-2438-or vehicle- treated mice were weighed on the same dates as tumors were measured. Body weight change is shown as percentage to the weight on the starting date. Points, mean (n = 8); bars, SE; *p < 0.01 vs. control.