Fig. 5

Identification of biomarkers associated with sensitivity to SHR6390. a Baseline expressions of CDK4/6 pathway related molecules in ESCC cell lines. The ESCC cell lines with high levels of CDK6 or low levels of Cyclin D1 expressions associated with reduced sensitivity to SHR6390. b Baseline expressions of CDK4/6 pathway related molecules in ESCC PDXs. The ESCC tumors untreated, from the same initial engraft were individually processed, and the levels of certain cell cycle proteins were analyzed. The PDXs with high levels of CDK6 or low levels of Cyclin D1 expressions associated with reduced sensitivity to SHR6390. c, d siRNA-mediated knockdown of CDK6 on CDK4/6 inhibition. Eca 109 and Eca 9706 cell lines were transfected with CDK6 siRNA or control siRNA. SHR6390 added 48 h after transfection. Cell proliferation was measured. After RNA interference against CDK6, Eca 109 and Eca 9706 cell lines showed an increased sensitivity to SHR6390