Fig. 3. Western blotting analysis of CDK8 protein, MTT analysis and bright field microscopy measurements in MDA-MB-231 cells. (a) Western blotting analysis of CDK8 levels. Immobilization of siRNA on NP surface shuts down the activity of siRNA (lanes 2 vs. 1) whereas addition of the tetrazine 2 activates the siRNA resulting in a remarkable decrease in the expression of CDK8 (lanes 3 vs. 1). β-Actin was used as a loading control. (b) Relative levels of cell proliferation measured by MTT assay; activated siRNA slows down proliferation of MDA-MB-231 cells due to knockdown of the CDK8 gene. (c) Brightfield image illustrating decreased population of MDA-MB-231 cells after silencing of CDK8 gene with the activation of prodrug using tetrazine.
