Upregulation of C-X-C chemokine receptor type 4 (CXCR4) in the breast cancer stem like cells.

BACKGROUND AND OBJECTIVES: Breast cancer stem like cells (CSCs) as a subset of cancer cells exhibit similar properties with normal stem cells. These cells are responsible for cancer metastasis and recurrence. Pivotal roles of CXCR4 in metastasis, chemoresistance and stemness of tumor cells have been showed previously. Here, we aim to explore the relationship between CXCR4 and CSCs in primary and metastatic breast tumor cells.

METHODS AND RESULTS: Primary and highly metastatic breast tumor cells were isolated in our laboratory. Spheroid formation was used to confirm the presence of CSCs and their self-renewal capability. CXCR4 expression was evaluated using real-time polymerase chain reaction in monolayer culture and multicellular spheroids. Our data showed that in all tested cells, CXCR4 expression was significantly increased in CSCs. In parallel, compared with primary tumor cells, downregulation of CXCR4 in metastatic tumor cells was confirmed.

CONCLUSION: These results provided new insights related to significant alteration of CXCR4 expression in multicellular spheroids. Analysis of molecular properties of spheroids could be used to detect molecular and genetic aspects of CSCs and also created a targeted therapeutic strategy against breast CSCs.