Co-treatment inhibits GBM growth and colony forming ability. A, Sample wells from anchorage independent growth assay where HSR-GBM1 cells were treated with vehicle, 2 μM MRK-003, 5 μM cyclopamine, or both drugs. B, upper graph, Growth of HSR-GBM1 in soft agar with treatment, repeated in triplicate; lower graph HSR-GBM1 pre-treated for seven days before plating in soft agar and then grown without drug. C, HSR-GBM2 and U87 grown in soft agar with drug treatment. Performed in triplicate for N=3 for all cell lines. * P<0.02, ** P<0.001, *** P<0.0001, using Student’s t-test.