Overexpression of 14-3-3γ causes polyploidization in H322 lung cancer cells

The 14-3-3 proteins are a family of highly conserved proteins that participate in a wide variety of cellular processes. Mounting evidence suggests that 14-3-3 proteins have a role in human cancers, however their role in tumorigenesis is unclear. Here we report that over-expression of 14-3-3 γ protein in human lung cancer cell line H322 results in abnormal DNA replication and polyploidization. Cells that overexpress 14-3-3 γ are resistant to microtubule inhibitors and can reenter the cell cycle in the absence of mitosis suggesting that elevated levels of 14-3-3 γ may enable cells to bypass the mitotic checkpoint. Taken together, our data indicate that 14-3-3γ may contribute to tumorigenesis by promoting genomic instability.