Bmi-1 was expressed in 53.2% of breast cancer patients by immunohistochemistry, and the expression of Bmi-1 was significantly correlated with favorable prognostic indices at diagnosis.
Bmi-1 mRNA is significantly up-regulated in adjacent normal breast tissue in breast cancer patients compared to normal breast tissue from noncancerous patients.
According to our data, significant elevation of the expression of miR-218 and downregulation of BMI1 were observed in clinical breast cancer specimens compared with normal tissues ( p < 0.0001).
Here we have made an endeavor to search whether any miRNAs are involved in the regulation of BMI1 in breast cancer that leads to mitochondrial dependent apoptotic cell death.
Here, we report that the expression of Bmi-1 and Mel-18 inversely correlates in a number of breast cancer cell lines and in a significant number of breast tumor samples.
In Caucasian populations, high expression of Bmi-1 was associated with better OS in breast cancer (HR=0.70, 95% CI 0.51-0.97), but it showed no significance in oesophageal carcinoma.
In the present study, we further demonstrated that 17-dimethylaminoethylamino-17-demethoxygeldanamycin (17-DMAG), an inhibitor of Hsp90, could suppress the self-renewal of BCSCs by downregulating B lymphoma Mo-MLV insertion region 1 homolog (BMI1), a polycomb family member with oncogenic activity in breast cancer.
Our data shows that PHGDH deficiency impairs the tumorsphere formation capacity in embryonal carcinoma stem-like cells (ECSLCs), breast cancer stem-like cells (BCSLCs) and patient-derived brain tumor-initiating cells (BTICs), which is accompanied by the reduced expression of characteristic stemness-promoting factors, such as Oct4, Nanog, Sox-2, and Bmi-1.
Our data suggest that the oncogenic role of Bmi-1 in human primary breast carcinomas is not determined by its capacity to inhibit INK4a/ARF proteins or to induce telomerase activity.
Polycomb group (PcG) protein BMI1 is an important regulator of oncogenic phenotype and is often overexpressed in several human malignancies including breast cancer.