Enzastaurin inhibits MM-cell growth. (A-B) Dose-related effects of enzastaurin on proliferation of indicated MM cell lines (A) and patient cells (B). Cells were cultured with indicated concentrations of enzastaurin. Uptake of [³H]-thymidine was measured during the last 10 hours of 48-hour cultures. (C) Enzastaurin decreases MM-cell adhesion to BMSCs. Spontaneous adherence of enzastaurin-treated and untreated MM cells to BMSCs was measured using calcein-am. (D-E) Enzastaurin inhibits proliferation of MM cells adherent to BMSCs. MM.1S cells (MM; D) or CD138⁺ MM cells (pat. MM) isolated from a multidrug-resistant patient with clinically progressive disease (E) were cultured with or without BMSCs. Enzastaurin was added in the indicated concentrations, and proliferation was measured using [³H]-thymidine uptake. Data shown are the mean ± SD of experiments performed in quadruplicate.