Ribociclib

The following antibodies: anti-GAPDH (FL-335), anti-K19 (A53-B/A2), anti-K8 (C51), anti-K18 (C-04), anti-cyclin D1 (DCS-6), anti-cyclin E (E-4), anti-cyclin A (H-3), anti-CDK1 (CDC2 p34(17)), anti-CDK4 (DCS-35), anti-CDK7 (C-4), anti-E2F1 (KH95) and anti-α tubulin (B-7) were from Santa Cruz Biotechnology (Santa Cruz, CA); anti-Rb (4H1), anti-phospho-Rb (Ser807/811), anti-E2F1, anti-cyclin D3 (DCS22) and anti-cyclin B1 (D5C10) were from Cell Signaling Technology (Danvers, MA). Palbociclib and ribociclib were from LC Laboratories (Woburn, MA) and THZ1 was from Cayman chemical (Ann Arbor, MI).

5×10³ cells were seeded in 12 well plates and treated 36 h later with the following drugs: CBZ (C-2581 LC Laboratories), DTX (D-1000, LC Laboratories), Camptothecin (CPT, 11694, Cayman Chemicals), Cytarabine (Ara-C, 16069, Cayman Chemicals), Doxorubicin (Dox, D-4000, LC Laboratories), Irinotecan (CPT-11; I-4122, LC Laboratories), ABCB1i Elacridar (# S7772, Selleck); CDK4/6 inhibitors: Palbociclib (P-7788, LC Laboratories), Ribociclib (R-8200, LC Laboratories), Abemaciclib (S5716, Selleckhem) according to protocols specified in individual experiments for the indicated time. Cells were fixed 9 days after seeding for 10 min with 4% formaldehyde and stained with crystal violet (0.5%). Images were acquired with Epson photo scanner and area of colonies were calculated using ImageJ software. Experiments were independently repeated at least three times in technical triplicates.