CDK4 and glioma: For example, some studies showed that the TRPC6 deficient mice is normal34, while knockdown TRPC6 arrested cell cycle at G2/M stage in U87 and U251 glioma cell lines35.Moreover, the Western blot assay showed that knockdown of RNF135 could attenuate the expression of the cell cycle protein CDK4 but enhance the expression of p27 Kip1 and p21 Waf1/Cip1.