Therapy-induced self-renewal of CD133hi cells regulates escape from tumor dormancy and endocrine-resistant metastatic luminal breast cancer. Homo sapiens

HT induces an OXPHOS metabolic editing of ER+ breast cancers, paradoxically establishing HT-driven self-renewal of dormant CD133hi/ERlo cells mediating metastatic progression, which is sensitive to dual targeted therapy In this study, we demonstrated that CD133hi cells can mediate HT resistance and metastatic progression. Using human luminal breast cancer cell lines we have developed an in vivo model of spontaneous metastatic disease recapitulating what is observed in patients. Combining in vivo and in vitro studies we identified a de-novo cancer stem cell population (CSCs) “CD133hi/ERlo/Notch3hi/IL6hi”, which are generated from non-CSCs via the sustained suppression of ER activity. We provide evidence that an ER-IL6-IL6R-CD133 loop is a mechanism mediating HT-resistance. Overall design: Cancer cells were isolated from primary tumor and metastases, labeled with anti-CD133/CD44 conjugated antibodies and FACS sorted (gated on GFP, cancer cells).For microarray gene expression profiling and real time PCR (QPCR), we extracted RNA using Trizol (Invitrogen) from FACS sorted tumour derived cells. RNA concentration was determined with a NanoDrop 2000. The samples were prepared according to standard protocols and hybridized them on Affymetrix HG-U133 A 2.0 microarrays. We normalized the data using Microarray Suite 5.0. Differentially expressed genes between groups were identified with fold-change and t-test cut-offs.