Remodeling metabolic pathways to regenerate new vulnerabilities in endocrine resistant breast tumors is novel, and given the need for better strategies to improve therapy response in relapsed ERα (+) tumors, our findings show great promise for uncovering the role that ERα-XPO1 crosstalk plays in reducing cancer recurrences.
Despite the effectiveness of endocrine therapies to treat estrogen receptor-positive (ER+) breast tumours, two thirds of patients will eventually relapse due to de novo or acquired resistance to these agents.
Comprehensive biomarker analysis of estrogen receptor (ER), progesterone receptor (PR), HER2, and Ki67 labeling index was performed on each tissue block of 100 entirely submitted breast tumors in 99 patients.
In in vivo study, CTX significantly inhibits growth of ER overexpressing breast tumor and, more importantly, based on the mechanism of CTX interacting with ERα, we found that CTX can target ER overexpressing breast tumors in vivo.
We assessed the associations between BMI and gene expression of both breast tumor and adjacent tissue in estrogen receptor-positive (ER+) and estrogen receptor-negative (ER-) diseases to help elucidate the mechanisms linking obesity with breast cancer biology in 519 post-menopausal women from the Nurses' Health Study (NHS) and NHSII.
Endogenous levels of both esterified and free sidechain-hydroxylated oxysterols were examined in breast cancer tumours from Estrogen Receptor positive and negative breast tumours, using a novel fast liquid chromatography tandem mass spectrometry method.
We found that low-density lipoprotein receptor-related protein 8 (LRP8) was more strongly expressed in estrogen receptor-negative breast tumors, including TNBCs and those overexpressing HER2, than in luminal breast tumors and normal breast tissues.
Immunohistochemical testing for estrogen receptor (ER), progesterone receptor (PR), human epidermal receptor factor-2 (HER-2), and Ki-67 proliferation index is performed daily to categorize breast tumors into different molecular subtypes.
Our findings were substantiated in a cohort of breast tumors in which IGF-1R expression was positively correlated with ERα/Src and ERα/PI3K expression, hallmarks of nongenomic estrogen signaling, reinforcing the link between IGF-1R and mERα.
Using publicly available data from The Cancer Genome Atlas, an amplification and gain of copy number of IGF1R was observed in 38% of triple-negative breast tumors (n=82), 26% of estrogen receptor (ER)-negative tumors (n=174) and 10% of ER-positive tumors (n=594).
ER can be classified into two receptors: estrogen receptor alpha (ERα) and beta (ERβ), and the former is expressed in 50~80% of breast tumors and has been extensively investigated in breast cancer for decades.