Background/aim: Accurate regulation of the spindle assembly checkpoint (SAC) and anaphase promoting complex/cyclosome (APC/C) are essential for the correct execution of mitosis. In this work, we focused on MAD2L2 (REV7), a central translesion (TLS) protein, which also functions as a mitotic regulator by inhibiting APC/C in prometaphase.
Materials and methods: Using bioinformatics analysis, live cell imaging and APC/C protein binding and degradation assays, we explored the influence of MAD2L2 over-expression in breast cancer.
Results: A significant over-expression of MAD2L2 was found in triple negative breast cancers (TNBC), compared to other breast cancers, correlating to poor patient prognosis. We also identified significant over-expression of MAD2L2 in the MDA-MB-157 triple negative (TN) cell line. A high percentage of MDA-MB-157 cells failed to complete mitosis and died during mitosis or shortly after. In addition, these cells completed mitosis at a significantly slower rate than control cells. MDA-MB-157 cells present high levels of mitotic slippage upon nocodazole treatment and acute dysregulation in APC/C function and substrate degradation. Moreover, silencing of MAD2L2 in the MDA-MB-157 cell line improved mitotic phenotypes.
Conclusion: MAD2L2 over-expression supports the carcinogenic phenotype of MDA-MB-157 cells by promoting uncontrolled mitosis.
Keywords: APC/C; MAD2L2; TNBC.
Copyright© 2020, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.