Maraviroc cooperated with trabectedin to decrease cell viability in three-dimensional heterospheroids formed by Hodgkin and Reed-Sternberg cells and classical Hodgkin lymphoma mesenchymal stromal cells. (A) Schedule of treatment of Hodgkin and Reed-Sternberg (HRS) cells and classical Hodgkin lymphoma mesenchymal stromal cells (cHL-MSC). (B) L-1236, or (C) HDLM-2 cells were cultured in non-adherent conditions with cHL-MSC (1.0 x 104/mL of each cell type) in 24-well plates and treated with trabectedin (360 pM) alone, maraviroc (100 mM) alone or in combination. Drugs were added immediately (add. T= 0) and after heterospheroid formation (add. T=24h). After 6 days, cell viability was evaluated using the PrestoBlue Cell Viability Reagent (Invitrogen). Values are mean and standard deviation of three experiments. °P<0.05 for T=0 vs. T=24h, Student t-test. *P<0.05 treatments vs. medium, One-way analysis of variance followed by the Dunnett test. (D) Representative phase contrast micrographs of heterospheroids cultured with trabectedin, maraviroc and their combination (T=0). MVC, maraviroc; TB, trabectedin. add., added.