Long Non-Coding RNA (LncRNA) UFC1/miR-34a Contributes to Proliferation and Migration in Breast Cancer

Abstract

BACKGROUND At present, a number of long non-coding RNAs (lncRNAs) have been realized as the critical regulators of breast cancers. Current evidence indicates that dysregulation of UFC1 contributes to the tumorigenesis and progression of various types of human cancer. However, the roles of UFC1 in breast cancer are still unclear. MATERIAL AND METHODS Firstly, we measured the expression of UFC1 in breast cancer tissues and cells lines compared with corresponding controls. Then, cell functional assays were performed to determine the roles of UFC1 in breast cancer progression in vitro. Moreover, the correlation between UFC1 and miR-34a was determined by luciferase reporter assays. Further, the role of miR-34a in regulating biological function of breast cancer and its downstream target CXCL10 was applied by a series of functional assays. RESULTS In present study, we found that UFC1 was highly expressed in breast tissue and cells lines compared with normal tissues and cell lines. Silenced UFC1 suppressed multiple biological activities of breast cancer cells, which also functioned as a miR-34a sponge in breast cancer. Furthermore, over-expressing miR-34a could prominently suppress cell growth, invasion, migration and inducing apoptosis in breast cancer cells. In addition, we verified that miR-34a was a target of CXCL10 by bioinformatics analysis and luciferase reporter assay. CONCLUSIONS LncRNA UFC1 regulated biological activity of breast cancer via miR-34a/CXCL10 axis, providing a novel diagnosis biomarker and potential therapeutic target for breast cancer.

Figure 1

UFC1 was highly expressed in breast tissues, indicating the poor prognosis of breast cancer patients. (A, B) RT-PCR was performed to test UFC1 expression in breast tissue specimens compared with adjacent non-tumor tissue. (C) The prognosis of breast cancer patients who had higher or lower UFC1 expression analyzed by Kaplan-Meier analysis and log-rank test. (D) The expression of UFC1 in human breast cancer cell lines (SKBR-3, BT-474,MDA-MB-231,MDA-MB-453, and MCF-7) as well as normal breast cell line (HBL-100). Data are presented as the mean±standard deviation. ** P<0.01 versus control group. RT-PCR – real-time polymerase chain reaction.

Figure 2

Silenced UFC1 repressed the biological activity breast cancer in vitro. (A) UFC1 expression in BT-474 and MDA-MB-231 cells transfected with si-UFC1 or si-NC was measured by RT-PCR. (B, C) CCK-8 assay and colony formation assay was conducted to evaluate the cell proliferation of breast cancer cells transfected with si-UFC1 or si-NC. (D, E) Transwell assay assessed the migration and invasion abilities of breast cancer cells transfected with si-UFC1 or si-NC. (F, G) The mRNA and protein expression of apoptotic and EMT related genes in breast cancer cells transfected with si-UFC1 or si-NC. Data are presented as the mean±standard deviation. ** P<0.01, * P<0.05 versus control group. NC – negative control; RT-PCR – real-time polymerase chain reaction; CCK-8 – Cell Counting Kit-8; EMT – epithelial-mesenchymal transition.

Figure 3

UFC1 acts as a miR-34a sponge in breast cancer. (A) Putative binding sites of miR-34a within the UFC1 predicted by bioinformatics tools. (B) Luciferase reporter assay was performed to validate relationship between UFC1 and miR-34a. (C) The expression of miR-34a in BT-474 and MAD-MB-231 cells transfected with si-UFC1 or si-vector by using RT-PCR. Data are presented as the mean±standard deviation. ** P<0.01, * P<0.05 versus control group. NC – negative control.

Figure 4

MiR-34a over-expression inhibits biological activity of breast cancer cells by targeting CXCL10. (A) Putative binding sites of miR-34a within the CXCL10 predicted by bioinformatics tools. (B) Luciferase reporter assay was performed to validate relationship between CXCL10 and miR-34a. (C, D) CCK-8 assay and colony formation assay was conducted to evaluate the cell proliferation of breast cancer cells transfected with miR-34a mimics or mimics-NC. (E, F) Transwell assay assessed the migration and invasion abilities of breast cancer cells transfected with miR-34a mimics or mimics-NC. (G, H) The mRNA and protein expression of apoptotic and EMT related genes in breast cancer cells transfected with miR-34a mimics or mimics-NC. (I) The protein levels of CXCL10 in BT-474 and MDA-MB-231 cells transfected with miR-34a mimics or mimics-NC. Data are presented as the mean±standard deviation. ** P<0.01, * P<0.05 versus control group. CCK-8 – Cell Counting Kit-8; NC – negative control; EMT – epithelial-mesenchymal transition.