CCND1 and hepatocellular carcinoma: As expected, western blot analysis showed that the protein expression of two major G1–S checkpoint regulators cyclin D1 and cyclin-dependent kinase was decreased in SNU-368 cells with H1HR knockdown, while overexpression of H1HR in HLE cells had opposite effect (Fig. 3b), confirming role of H1HR in promoting cell cycle progression in HCC cells.