Inhibition of the CDK4/6-Cyclin D-Rb Pathway by Ribociclib Augments Chemotherapy and Immunotherapy in Renal Cell Carcinoma

Figure 2

Ribociclib significantly enhances the in vitro efficacy of chemotherapy and immunotherapy in sensitive but not resistant RCC cell lines. Combination of ribociclib with 5-FU (chemotherapeutic agent) or IFN-α (immunotherapeutic agent) is significantly more effective in inhibiting proliferation (a) and inducing apoptosis (b) than 5-FU or IFN-α alone in sensitive but not resistant cell lines. Results shown in (a) are relative to control (value set as 1). 5-FU at 1 μM and IFN-α at 100 IU/ml were used in the combination assays in all tested RCC cell lines. Ribociclib at 0.1 μM in 786-O, CaKi-2, SW839, and UM-RC-2 cell lines, at 0.2 μM in 769-P, A-704, and ACHN, and at 0.8 μM in CaKi-1 and A498 cell lines was used for the proliferation assay. Ribociclib at 0.8 μM in 786-O, CaKi-2, SW839, and UM-RC-2 cell lines and at 1.6 μM in 769-P, A-704, ACHN, CaKi-1, and A498 cell lines was used for the apoptosis assay. , compared to 5-FU or IFN-α alone.

(a)

(b)