RESUMO
CD133 has been associated with cell properties such as self renewal, migration and vasculogenic mimicry, potentially involved in generation of circulating tumor cells (CTCs). We characterized CD133 expression in CTCs of 98 nometastatic breast cancer (BC) patients. CTCs were isolated by immunomagnetic techniques using magnetic beads labeled with a multicytokeratin(CK)-specific antibody (CK3-11D5) and CTCs and CD133 detection through immunocytochemical methods. CK(+) /CD133(+) CTCs were identified in 65% of patients at baseline and 47.8% after systemic therapy (p = 0.53). Correlation of CD133 status in CTCs with classical clinicopathological characteristics and response to therapy was performed. Her2 not amplified and low Ki-67 index were positively correlated with presence of CK(+) /CD133(+) CTCs. Before any treatment, CK(+) /CD133(+) CTCs were more frequently isolated in patients with luminal BC subtype. No statistically significant differences were found between proportion of CK(+) /CD133(+) CTCs and BC subtypes after systemic therapy, implying a relative enrichment of CK(+) /CD133(+) CTCs in triple negative and HER2-amplified tumors. While CK(+) /CTCs decreases after chemotherapy when analyzing the whole population, CK(+) /CD133(+) CTCs were enriched in post-treatment samples in nonluminal BC subtypes. These findings suggest the potential role of CD133 as a promising marker of chemoresistance in nonluminal BC patients. Further prospective studies and extensive preclinical modeling will be needed to confirm whether CD133 is a marker of resistance to chemotherapy, and its role as a target for novel anticancer therapies targeting cancer stem cells and tumor vasculature.
Assuntos
Antígenos CD/biossíntese , Glicoproteínas/biossíntese , Células Neoplásicas Circulantes/metabolismo , Neoplasias de Mama Triplo Negativas/metabolismo , Neoplasias de Mama Triplo Negativas/patologia , Antígeno AC133 , Antígenos CD/genética , Antígenos CD/metabolismo , Linhagem Celular Tumoral , Resistencia a Medicamentos Antineoplásicos , Feminino , Glicoproteínas/genética , Glicoproteínas/metabolismo , Humanos , Separação Imunomagnética/métodos , Antígeno Ki-67/genética , Antígeno Ki-67/metabolismo , Células MCF-7 , Pessoa de Meia-Idade , Peptídeos/genética , Peptídeos/metabolismo , Receptor ErbB-2/genética , Receptor ErbB-2/metabolismo , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Neoplasias de Mama Triplo Negativas/genéticaRESUMO
Circulating Tumor Cells (CTCs) are a valuable prognostic factor in several solid tumors. By understanding the biological characteristics of CTCs we could better understand the biology of metastasis. CTCs usually adopt a dormant state that is believed to be a strategy to survive in extreme conditions. To enter a dormant state, CTCs undergo numerous phenotypic, genetic and functional mutations that significantly affect the efficacy of the therapies used to kill dormant CTCs. Hence, understanding the biological events involved in the dormancy process of CTCs would allow the identification of new therapeutic targets. Some experimental studies or preclinical models have explored these biological events, as well as the molecular factors that contribute to the maintenance of and release from dormancy. However, few studies have assessed the effects of anticancer therapies on dormant cells. This study reviews current the data currently available on cell dormancy mechanisms in prostate cancer, with a special focus on the functional, genetic and phenotypic plasticity of CTCs and their potential implications in the clinical and therapeutic management of prostate cancer.