Breast cancer is the most common
malignancy in females and poses a significant health threat to women.
Pregnancy-associated plasma protein-A (PAPPA) is highly expressed in pregnancy-associated
breast cancer (
PABC) tissues. In this study, we investigated the functional role of PAPPA in regulating the malignant phenotype of
breast cancer. We first examined the expression level of PAPPA in
PABC tissue and
breast cancer cell lines using quantitative real-time polymerase-chain reaction (qRT-PCR) and western blot. Next, the functional role of PAPPA in
breast cancer cells was validated by overexpression and knockdown experiments. Cell counting kit-8 (CCK-8) proliferation assay,
5-ethynyl-2'-deoxyuridine (EdU) incorporation assay, wound healing and transwell invasion assay were used to examine cell proliferation, migration, and invasion ability. We further identified the
microRNA target regulating PAPPA and studied its functional role. Finally, we examined the impact of PAPPA on the
tumorigenesis and
metastasis of
breast cancer in mice model. Our study revealed that PAPPA was upregulated in
PABC tissues and
breast cancer cells. Overexpression of PAPPA promoted cell proliferation, motility, invasion, and epithelial-mesenchymal transition (EMT). We further identified miR-497-5p as a negative regulator of PAPPA, which suppressed cell proliferation, migration, invasion, and EMT in
breast cancer cells. We also validated the oncogenic role of PAPPA in the mouse xenograft model. Collectively, our study suggests that PAPPA is an oncogenic
protein highly expressed in
PABC tissues and promotes
breast cancer progression, which could serve as a novel therapeutic target for
breast cancer.