Prostate Apoptosis Response-4 (PAR4) Suppresses Growth and Invasion of Breast Cancer Cells and Is Positively Associated with Patient Survival.

BACKGROUND

Prostate apoptosis response-4 (PAR4) plays an important role in apoptosis and survival of cancer cells. The current study aimed to further elucidate its role in breast cancer.

MATERIALS AND METHODS

PAR4 expression in human breast cancer tissue was examined using quantitative polymerase chain reaction (qPCR) and immunohistochemical staining (IHC). Plasmids containing full-length human PAR4 coding sequence were used to overexpress PAR4 in breast cancer cells and the effect on cellular functions was examined using both in vitro functional assays and an in vivo murine model.

RESULTS

Patients with low PAR4 transcript levels had poorer overall survival. PAR4 expression may be associated with differential expression of oestrogen receptors α and β in the tumours. Overexpression of PAR4 in MDA-MB-231 cells resulted in reduced cell growth and invasion, and also reduced in vivo tumour growth.

CONCLUSION

Decreased PAR4 expression in breast cancer is associated with shorter survival. PAR4 suppresses growth and invasiveness of breast cancer cells.