Degradation of CCNB1 mediated by APC11 through UBA52 ubiquitination promotes cell cycle progression and proliferation of non-small cell lung cancer cells.

OBJECTIVE

Mechanism by which CCNB1 regulates the cell cycle progression and its prognostic function in non-squamous non-small cell lung cancer (NSCLC) are necessary to be further elucidated.

METHODS

Data retrieved from gene expression omnibus (GEO) and cancer genome atlas (TCGA) combined with clinical data were used. Survival analysis was conducted in public datasets. Proteomics and co-immunoprecipation assays were designed to unravel proteins with interaction with CCNB1. Short hairpin RNA and small interfering RNA as well as overexpressing genes of interest were used.

RESULTS

CCNB1 was not implicated in apoptosis, migration and invasion of NSCLC cells. After either knockdown or overexpression of CCNB1, the occurrence of cell cycle arrest in G2/M phase, fewer cloning formation and diminished dimension of xenograft tumors were observed. CCNB1 expression level was clinically associated with several clinicopathological parameters including gender, smoking, T stage and N stage. Survival analysis showed that the higher level of CCNB1, the more dismal outcome in overall survival as well as in disease-free survival. Mechanistically, we confirmed that the role of CCNB1 on cell cycle and cloning formation was dependent on UBA52, which was able to promote degradation of CCNB1; nevertheless, this consequence relied on APC11. Knockdown of APC11 led to cell cycle arrest in G2/M and less cloning formation even in the presence of overexpressed UBA52. Following upregulation of APC11, the protein of CCNB1 degraded with resultant cell cycle progression and more cloning formation.

CONCLUSION

Degradation of CCNB1 by APC11 via UBA52 ubiquitylation was critical in cell cycle progression and proliferation of NSCLC cell lines.