Background: Bladder cancer (BC) is one of the most prevalent malignancies of the genitourinary system, yet the underlying mechanism of BC progression still remains unclear. Growth arrest and DNA damage-inducible 45 alpha (GADD45a) is a repressive gene implicated in cell cycle regulation, as well as in human cancers development. However, its role in BC remains to be determined.
Methods: First, quantitative real-time polymerase chain reaction (PCR) and Western blot assays were used to detect GADD45a expression in BC tissues and adjacent non-tumor tissues, as well as in bladder cancer cell lines, respectively. Then, cell counting kit-8 (CCK-8) assays, colony formation assays, and flow cytometry assays were used to measure the ability of cell growth, proliferation and cell cycle distribution. Lentiviral infection technology was used to increase gene expression, while siRNA interfering technology was used to knockdown gene expression. Finally, nude mice were used to construct tumor-burdened models in vivo by injecting tumor cells subcutaneously.
Results: PCR results showed that the level of GADD45a mRNA and protein levels were lower in BC tissues than in adjacent normal tissues. After increasing GADD45a expression, both the ability of growth and proliferation of BC cells were seriously impaired. Additionally, the upregulation of GADD45a expression resulted in BC cell cycle in G2/M and S phases in a p53-regulated pathway.
Conclusion: GADD45a-mediated cell cycle inhibition is regulated by p53 in bladder cancer cells.
Keywords: GADD45a, bladder cancer, cell cycle, p53, proliferation