RESUMO
Many solid cancers are hierarchically organized with a small number of cancer stem cells (CSCs) able to regrow a tumor, while their progeny lacks this feature. Breast CSC is known to contribute to therapy resistance. The study of those cells is usually based on their cell-surface markers like CD44high /CD24low/neg or their aldehyde dehydrogenase (ALDH) activity. However, these markers cannot be used to track the dynamics of CSC. Here, a transcriptomic analysis is performed to identify segregating gene expression in CSCs and non-CSCs, sorted by Aldefluor assay. It is observed that among ALDH-associated genes, only ALDH1A1 isoform is increased in CSCs. A CSC reporter system is then developed by using a far red-fluorescent protein (mNeptune) under the control of ALDH1A1 promoter. mNeptune-positive cells exhibit higher sphere-forming capacity, tumor formation, and increased resistance to anticancer therapies. These results indicate that the reporter identifies cells with stemness characteristics. Moreover, live tracking of cells in a microfluidic system reveals a higher extravasation potential of CSCs. Live tracking of non-CSCs under irradiation treatment show, for the first time, live reprogramming of non-CSCs into CSCs. Therefore, the reporter will allow for cell tracking to better understand the implication of CSCs in breast cancer development and recurrence.
Assuntos
Família Aldeído Desidrogenase 1/genética , Neoplasias da Mama/genética , Rastreamento de Células , Perfilação da Expressão Gênica , Genes Reporter , Células-Tronco Neoplásicas/metabolismo , Células-Tronco Neoplásicas/patologia , Retinal Desidrogenase/genética , Animais , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Biomarcadores Tumorais/metabolismo , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Reprogramação Celular/efeitos dos fármacos , Feminino , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Genoma Humano , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Células Endoteliais da Veia Umbilical Humana/metabolismo , Humanos , Camundongos Endogâmicos NOD , Camundongos SCID , Células-Tronco Neoplásicas/efeitos dos fármacos , Regiões Promotoras Genéticas/genética , Reprodutibilidade dos TestesRESUMO
AIM: To assess the value of post-mastectomy radiation therapy (PMRT) to breast cancer (BC) patients with no or minimal lymph node (LN) involvement. MATERIALS AND METHODS: We retrospectively analysed a French multi-centric cohort of 4283 patients treated by mastectomy and axillary dissection, with or without PMRT, between 1980 and 2013. Practices were analysed for three treatment periods (1980-1999, 2000-2005 and 2006-2013). The impact of PMRT on loco-regional recurrence (LRR), disease-free survival (DFS), BC-specific survival and overall survival was assessed in pN0-1mi patients using multivariate analyses (logistic regression and Cox model). It was subsequently assessed based on the number of clinicopathological recurrence-risk factors, generating a prognostic index (French-PMRT index), to isolate a pN0-1mi patients subgroup that might derive a benefit from PMRT. We tested the accuracy of the Cambridge-PMRT (c-PMRT) index to discriminate between patients with significantly different outcomes and the value of PMRT in each c-PMRT prognostic group. RESULTS: More than half of the pN0-1mi patients of our cohort underwent PMRT, which almost significantly improved LRR-free survival and DFS. Matching pN0-1mi patients based on the number of clinicopathologic recurrence-risk factors identified a higher risk subpopulation (≥3 recurrence-risk factors), but PMRT did not improve patient outcomes. Although the c-PMRT index had the potential to predict patient outcomes, its use did not help in making the decision of whether or not to use PMRT. CONCLUSION: We failed to isolate a subgroup of early BC patients without LN involvement suitable for PMRT, despite studying a large cohort.