High percentage of Cancer Stem cells in metastatic locations: Upregulation of cicBIRC6 in highly metastatic breast Cancer Subline.

Abstract

Metastasis is a devastating complication of breast cancer. Cancer relapse and metastasis are associated with cancer stem cells. CicBIRC6 is a circular RNA that is proposed to be involved in the stemness of stem cells. In breast cancer, metastatic tumor cells have higher stem cell properties. In the present study, we evaluate the expression of cicBIRC6 in these cells. After the development of a syngeneic animal model of TNBC, primary breast cancer cells named 4T1T were isolated from the tumor mass. Highly metastatic tumor cells named 4T1B and 4T1L were isolated and expanded from brain metastasis lesions and lungs of cancerous mice respectively. Sphere formation ability in metastatic and primary tumor cells was evaluated separately. The quantitative real-time polymerase chain reaction was performed to analyze the expression of cicBIRC6 in primary and metastatic tumor cells. Our data revealed that, sphere formation ability among metastatic tumor cells was significantly higher. Surprisingly expression of cicBIRC6 was significantly upregulated in these metastatic tumor cells. In comparison with 4T1T, cicBIRC6 was upregulated 5.7 and 3.5 times in 4T1B and 4T1L respectively. These findings provided important insights regarding the molecular properties of metastatic tumor cells and can be used for designing a targeted therapeutic strategy in combat with these cells.