The high mobility group protein A2 (HMGA2) has been demonstrated as an architectural transcription factor that is associated with pathogenesis of many malignant cancers, however, its role in prostate cancer cells remains largely unknown. To explore whether HMGA2 participates in the development and progression of prostate cancer, small interfering RNA (siRNA) targeted on human HMGA2 was transfected to suppress the HMGA2 expression in prostate cancer PC3 and DU145 cells, and then we examined the cellular biology changes after decreased the expression of HMGA2. Our results showed that knockdown of HMGA2 markedly inhibited cell proliferation, this reduced cell proliferation was due to the promotion of cell apoptosis as the Bcl-xl was decreased, whereas Bax was up-regulated. In addition, we found that HMGA2 knockdown resulted in reduction of cell migration and invasion, as well as repressed the expression of matrix metalloproteinases (MMPs) and affected the occurrence of epithelial-mesenchymal transition (EMT) in both cell types. We further found that decreased HMGA2 expression inhibited the transforming growth factor-β (TGF-β)/Smad signaling pathway in cancer cells. In conclusion, our data indicated that HMGA2 was associated with apoptosis, migration and invasion of prostate cancer, which might be a promising therapeutic target for prostate cancer.

Cripto-1 (CR-1) is a member of the epidermal growth factor-Cripto-1/FRL1/Cryptic gene family that plays a key role in thevarious malignant cancers. However, the role of CR-1 in prostate carcinoma (PCa) remains limited. The expression of CR-1was down-regulated by small interfering RNA (siRNA). Western blot measured the expression levels of CR-1 and somerelated proteins. We performed Cell Counting Kit-8, 5-ethynyl-2-deoxyuridine (EdU) incorporation assay and flowcytometry to detect the cellular proliferation and cycle. The transwell assay was used to observe cellular migration andinvasion. The ability of angiogenesis was evaluated by tube formation assay. Our results showed that CR-1 knockdownmarkedly inhibited cell proliferation and induced cycle arrest in G1 phase, as p21 and p27 were up-regulated, whereascyclin D1 and cyclin E1 were diminished. Moreover, silencing of CR-1 dramatically inhibited cell migration and invasion,repressed matrix metalloproteinases, and disturbed epithelial-mesenchymal transition. CR-1 siRNA suppressed the secretedlevel of vascular endothelial growth factor, and reduced protein level of Vascular endothelial growth factor receptor 2. Wefurther found that decreased CR-1 expression inhibited FAK/Src/PI3K and Wnt/b-catenin signalling in PCa cells. Theseresults suggested CR-1 might be served as an effective therapeutic target in PCa.

The Homeobox B9 (HOXB9) is a homeodomain-containing transcription factor that participates in the progressionof various malignancies. Nevertheless, the functional role of HOXB9 in prostate cancer cells is largelyunknown. Hence, we aimed to address the effect of HOXB9 on the progression of prostate cancer cells. Smallinterfering RNA (siRNA) against HOXB9 was used to downregulate HOXB9 expression in PC3 and DU145cells. Western blotting was performed to detect the expression levels of HOXB9 and other related proteins. Cellproliferation was tested by the Cell Counting Kit-8 (CCK-8) and cell cycle and apoptosis were investigated byflow cytometry. Angiogenesis was examined using tube formation assays The Transwell assays were carriedout to assess the migratory and invasive capacities of cells. Here, we found that HOXB9 knockdown significantlyreduced cell proliferation via inducing cell cycle arrest at G1 phase. This treatment also reducedangiogenesis, migration and invasion abilities of PC3 and DU145 cells in vitro. We also found that HOXB9knockdown inhibits the activation of the PI3K/AKT signaling pathway in prostate cancer cells. In conclusion,our findings revealed that HOXB9 promotes prostate cancer progression and might be a novel and effectivetherapeutic target for human prostate cancer.