Inhibitor of apoptosis protein-like protein-2: A novel growth accelerator for breast cancer cells

Although the inhibitor of apoptosis protein-like protein-2 (ILP-2) has been shown as a serological biomarker for breast cancer, its effect on breast cancer cell growth remains elusive. The present study aimed to determine the role of ILP-2 in breast cancer cell growth. We used immunohistochemistry to analyze ILP-2 expression in 59 tissue paraffin-embedded blocks, which included 35 breast cancer tissues and 24 galactophore hyperplasia tissues. Western blot analysis was used to detect protein expression levels of ILP-2 in breast cancer cell lines such as HCC-1937, MX-1 and MCF-7 as well as breast gland cell line MCF 10A. ILP-2 was silenced by siRNA in HCC-1937, MX-1 and MCF-7 cell lines. MTT assays, scratch assays and AO-EB double staining analysis were conducted to evidence the role of ILP-2 on breast cancer cell growth. Results from this study showed increased ILP-2 expression in breast cancer tissues and breast cancer cell lines such as HCC-1937, MX-1 and MCF-7. Cell viability or rate of cell migration of HCC-1937, MX-1 and MCF-7 cell lines was significantly inhibited when ILP-2 was knocked down by siRNA. The apoptosis rate of HCC-1937, MX-1 and MCF-7 cell lines was increased when compared with that of the control group. Thus, ILP-2 plays an active role in the growth of breast cancer cells.