Background: Breast cancer is among the most common malignant cancers worldwide, and
breast adenocarcinoma in glandular tissue cells has excessive metastasis and invasion capability. However,
little is known on the molecular process by which this disease develops and progresses.
Objective: In this study, we explored the effects of sex-determining region Y-box 4 (SOX4) protein on
proliferation, migration, apoptosis and tumourigenesis of breast adenocarcinoma and its possible
Methods: The SOX4 overexpression or knockdown Michigan Cancer Foundation-7 (MCF-7) cell lines
were established. Among the SOX4 overexpression or MCF-7 knockdown cell lines, proliferation,
migration ability and apoptosis rate were detected. The expression levels of apoptosis-related proteins
(Bax and Cleaved caspase-3) were analysed using Western blot. The effect of SOX4 on tumourigenesis
was analysed using the clone formation assay in vitro and tumour xenograft experiment in nude mice.
Results: Compared with the overexpression of control cells, proliferation and migration ability of
SOX4 overexpression cells significantly increased, the apoptosis rate significantly decreased in addition
to the expression levels of Bax and Cleaved caspase-3 (P < 0.05). Compared with the knockdown of
control cells, proliferation and migration ability of SOX4 knockdown cells significantly decreased, and
the apoptosis rate and expression levels of Bax and Cleaved caspase-3 significantly increased (P < 0.05).
Clone formation and tumour growth abilities of SOX4 overexpression cells were significantly higher
than those of the control cells (P < 0.05), whereas SOX4 knockdown cells had the opposite effect.
Conclusion: SOX4 plays an oncogenic role in breast adenocarcinoma tumourigenesis by promoting
cell proliferation, migration and inhibiting apoptosis. It can be used as a potential molecular target for
breast cancer gene therapy.