Overexpression of Notch1 could reverse EGFR inhibitor-induced cell toxicity, suggesting that Notch and EGFR signaling may be positively cross-linked in human breast cancer.
Additionally, GASC1 demethylase activity regulates the expression of genes critical for stem cell self-renewal, including NOTCH1, and may be linked to the stem cell phenotypes in breast cancer.
Overall, we detected three NOTCH mutations in the cancers, which consisted of one NOTCH1 mutation in the T-ALLs (25.0%), one NOTCH2 mutation in the breast carcinomas (2.1%), and one NOTCH3 mutation in the colorectal carcinomas (2.0%).
Consistent with this mechanistic link, Notch1 and Myc expression is positively correlated by immunostaining in 38% of examined human breast carcinomas.
We show here that 17 beta-estradiol promoted a 6-fold increase in Jagged1 expression and an 8-fold increase in Notch1 expression by cDNA arrays in breast cancer MCF7 cells.