3.

CSN6 negatively regulates the expression of p16. (A) Protein expression levels of CSN6, cyclin D, CDK4, p16 and p21 were analyzed by Western blot in MKN-45 and MGC-803 cells after knockdown or overexpression of CSN6. Lysates were immunoblotted with the indicated antibodies. (B) CSN6 reduced the protein level of p16 in a dose-dependent manner in MKN-45 and MGC-803 cell lines. Equal amounts of cell lysates were immunoblotted with the indicated antibodies. (C) MKN-45 and MGC-803 cells were co-transfected with p16 plasmid and increasing amounts of CSN6. CSN6 negatively regulates the steady-state expression of p16 in a dose-dependent manner. Equal amounts of cell lysates were immunoblotted with the indicated antibodies. (D) Overexpression of CSN6 promoted the cell clone formation. Restoration of p16 rescued the augmention of cell clone formation. (E) Overexpression of CSN6 promoted cell proliferation. Restoration of p16 rescued the promotion of cell proliferation. The data represent the mean ± SD (* or ^#P ≤ 0.05, ** or ^##P ≤ 0.01).