BCSC-1 suppresses human breast cancer metastasis by inhibiting NF-κB signaling

Breast cancer suppressor candidate-1 (BCSC-1; also termed von Willebrand factor A domain containing 5A and LOH11CR2A) is a newly identified candidate tumor suppressor gene that has been implicated in several types of cancer in previous studies. However, there have been few reports about the association between BCSC-1 and human breast cancer in recent years. In the present study, the expression of BCSC-1 in breast cancer was determined by immunohistochemistry (IHC) staining of tissue microarrays and clinical tissue specimens. Subsequently, BCSC-1 gene expression was evaluated in different breast cancer cell lines by quantitative polymerase chain reaction and the MDA-MB-231 cell line was selected for further use in subsequent experiments, due to its low BCSC-1 expression. An MDA-MB-231 cell line with stable overexpression of BCSC-1 was established through transfection with plasmid containing the BCSC-1 gene, and then screening for G418 resistance. Wound-healing, migration and invasion assays were conducted to detect the effect of BCSC-1 on MDA-MB-231 cells. Furthermore, changes in matrix metalloproteinases (MMPs), osteopontin (OPN) and the nuclear factor-κB (NF-κB) pathway were detected in the current study. Additionally, stable silencing of BCSC-1 expression in MCF-7 cells was performed using a lentivirus. The results of IHC indicated that BCSC-1 is expressed at low levels in breast cancer tissues compared with in normal breast tissue. Results of the wound healing, migration and invasion assays demonstrated that BCSC-1 overexpression reduced the metastasis ability of MDA-MB-231 cells in vitro. Further research confirmed that the BCSC-1 overexpression reduced the expression levels of MMP7, MMP9 and OPN, and the phosphorylation of NF-κB p65. Furthermore, inhibition of BCSC-1 via lentivirus-mediated RNA interference revealed that the downregulation of BCSC-1 increased the invasive ability of MCF-7 cells. In summary, the results demonstrated that BCSC-1 is expressed at low levels in breast cancer tissues, and that it can suppress human breast cancer cell migration and invasion, potentially altering the expression of MMP7, MMP9, OPN, and the activity of the NF-κB pathway. Therefore, BCSC-1 may be useful as a biomarker for the treatment of breast cancer in the future.